Effectiveness of 13-valent pneumococcal conjugate vaccine for prevention of invasive pneumococcal disease among children in the United States between 2010 and 2019: An indirect cohort study

BACKGROUND

A U.S. case-control study (2010-2014) demonstrated vaccine effectiveness (VE) for ≥ 1 dose of the thirteen-valent pneumococcal conjugate vaccine (PCV13) against vaccine-type (VT) invasive pneumococcal disease (IPD) at 86 %; however, it lacked statistical power to examine VE by number of doses and against individual serotypes.

METHODS

We used the indirect cohort method to estimate PCV13 VE against VT-IPD among children aged < 5 years in the United States from May 1, 2010 through December 31, 2019 using cases from CDC's Active Bacterial Core surveillance, including cases enrolled in a matched case-control study (2010-2014). Cases and controls were defined as individuals with VT-IPD and non-PCV13-type-IPD (NVT-IPD), respectively. We estimated absolute VE using the adjusted odds ratio of prior PCV13 receipt (1-aOR x 100 %).

RESULTS

Among 1,161 IPD cases, 223 (19.2 %) were VT cases and 938 (80.8 %) were NVT controls. Of those, 108 cases (48.4 %; 108/223) and 600 controls (64.0 %; 600/938) had received > 3 PCV13 doses; 23 cases (17.6 %) and 15 controls (2.4 %) had received no PCV doses. VE ≥ 3 PCV13 doses against VT-IPD was 90.2 % (95 % Confidence Interval75.4-96.1 %), respectively. Among the most commonly circulating VT-IPD serotypes, VE of ≥ 3 PCV13 doses was 86.8 % (73.7-93.3 %), 50.2 % (28.4-80.5 %), and 93.8 % (69.8-98.8 %) against serotypes 19A, 3, and 19F, respectively.

CONCLUSIONS

At least three doses of PCV13 continue to be effective in preventing VT-IPD among children aged < 5 years in the US. PCV13 was protective against serotypes 19A and 19F IPD; protection against serotype 3 IPD did not reach statistical significance.

Evaluation of Asymptomatic Bordetella Carriage in a Convenience Sample of Children and Adolescents in Atlanta, Georgia, United States

Few data exist on asymptomatic carriage of Bordetella species among populations receiving acellular pertussis vaccine. We conducted a cross-sectional study among acellular-vaccinated children presenting to an emergency department (ED). Bordetella pertussis carriage prevalence was <1% in this population, a lower prevalence than that found in recent studies among whole-cell pertussis-vaccinated participants.

Epidemiology of Invasive Nontypeable Haemophilus influenzae Disease-United States, 2008-2019

BACKGROUND

Nontypeable Haemophilus influenzae (NTHi) is the most common cause of invasive H. influenzae disease in the United States (US). We evaluated the epidemiology of invasive NTHi disease in the US, including among pregnant women, infants, and people with human immunodeficiency virus (PWH).

METHODS

We used data from population- and laboratory-based surveillance for invasive H. influenzae disease conducted in 10 sites to estimate national incidence of NTHi, and to describe epidemiology in women of childbearing age, infants aged ≤30 days (neonates), and PWH living in the surveillance catchment areas. H. influenzae isolates were sent to the Centers for Disease Control and Prevention for species confirmation, serotyping, and whole genome sequencing of select isolates.

RESULTS

During 2008-⁠2019, average annual NTHi incidence in the US was 1.3/100 000 population overall, 5.8/100 000 among children aged <1 year, and 10.2/100 000 among adults aged ≥80 years. Among 225 reported neonates with NTHi, 92% had a positive culture within the first week of life and 72% were preterm. NTHi risk was 23 times higher among preterm compared to term neonates, and 5.6 times higher in pregnant/postpartum compared to nonpregnant women. More than half of pregnant women with invasive NTHi had loss of pregnancy postinfection. Incidence among PWH aged ≥13 years was 9.5 cases per 100 000, compared to 1.1 cases per 100 000 for non-PWH (rate ratio, 8.3 [95% confidence interval, 7.1-9.7]; P < .0001).

CONCLUSIONS

NTHi causes substantial invasive disease, especially among older adults, pregnant/postpartum women, and neonates. Enhanced surveillance and evaluation of targeted interventions to prevent perinatal NTHi infections may be warranted.

Changes in the Incidence of Invasive Bacterial Disease During the COVID-19 Pandemic in the United States, 2014-2020

BACKGROUND

Descriptions of changes in invasive bacterial disease (IBD) epidemiology during the coronavirus disease 2019 (COVID-19) pandemic in the United States are limited.

METHODS

We investigated changes in the incidence of IBD due to Streptococcus pneumoniae, Haemophilus influenzae, group A Streptococcus (GAS), and group B Streptococcus (GBS). We defined the COVID-19 pandemic period as 1 March to 31 December 2020. We compared observed IBD incidences during the pandemic to expected incidences, consistent with January 2014 to February 2020 trends. We conducted secondary analysis of a health care database to assess changes in testing by blood and cerebrospinal fluid (CSF) culture during the pandemic.

RESULTS

Compared with expected incidences, the observed incidences of IBD due to S. pneumoniae, H. influenzae, GAS, and GBS were 58%, 60%, 28%, and 12% lower during the pandemic period of 2020, respectively. Declines from expected incidences corresponded closely with implementation of COVID-19-associated nonpharmaceutical interventions (NPIs). Significant declines were observed across all age and race groups, and surveillance sites for S. pneumoniae and H. influenzae. Blood and CSF culture testing rates during the pandemic were comparable to previous years.

CONCLUSIONS

NPIs likely contributed to the decline in IBD incidence in the United States in 2020; observed declines were unlikely to be driven by reductions in testing.

416. Evaluating Indwelling Devices and Mortality in Invasive Carbapenem-Resistant Enterobacterales Infections, Atlanta, GA, 2012–2019

Background

Carbapenem-resistant Enterobacterales (CRE) infections pose a grave public health threat due to the potentially silent transmission leading to outbreaks, limited therapeutic options and high mortality. We sought to identify risk factors for mortality in patients with invasive CRE infections and describe the association between indwelling medical devices and 90-day mortality.

Methods

The Georgia Emerging Infections Program performs active population and laboratory based surveillance for CRE in the Atlanta, Georgia metropolitan area. Using this data we created a retrospective observational cohort of patients with invasive CRE infections between 2012 and 2019. Invasive infections were defined as resistant isolates obtained from a normally sterile site (Table 1). Indwelling medical devices, including central venous catheters (CVCs), were present within two calendar days prior to infection.

We completed bivariate analyses examining the relationship between covariates and mortality. Multivariable log binomial regression was used to estimate adjusted risk ratios (aRR) for the association of covariates and all-cause 90-day mortality. Sub-group analyses were completed evaluating only those patients with CVCs and those with at least two indwelling devices. Table 1.

Recurrent Candidemia: Trends and Risk Factors Among Persons Residing in 4 US States, 2011-2018

Background

Candidemia is a common healthcare-associated infection with high mortality. Estimates of recurrence range from 1% to 17%. Few studies have focused on those with recurrent candidemia, who often experience more severe illness and greater treatment failure. We describe recurrent candidemia trends and risk factors.

Methods

We analyzed population-based candidemia surveillance data collected during 2011-2018. Persons with >1 episode (defined as the 30-day period after a positive Candida species) were classified as having recurrent candidemia. We compared factors during the initial episode between those who developed recurrent candidemia and those who did not.

Results

Of the 5428 persons identified with candidemia, 326 (6%) had recurrent infection. Recurrent episodes occurred 1.0 month to 7.6 years after any previous episode. In multivariable logistic regression controlling for surveillance site and year, recurrent candidemia was associated with being 19-44 years old (vs ≥65 years; adjusted odds ratio [aOR], 3.05 [95% confidence interval {CI}, 2.10-4.44]), being discharged to a private residence (vs medical facility; aOR, 1.53 [95% CI, 1.12-2.08]), hospitalization in the 90 days prior to initial episode (aOR, 1.66 [95% CI, 1.27-2.18]), receipt of total parenteral nutrition (aOR, 2.08 [95% CI, 1.58-2.73]), and hepatitis C infection (aOR, 1.65 [95% CI, 1.12-2.43]).

Conclusions

Candidemia recurrence >30 days after initial infection occurred in >1 in 20 persons with candidemia. Associations with younger age and hepatitis C suggest injection drug use may play a modifiable role. Prevention efforts targeting central line care and total parenteral nutrition use may help reduce the risk of recurrent candidemia.

Low sensitivity of ICD-10 coding for culture-confirmed candidemia cases in an active surveillance system—United States, 2019–2020

We evaluated healthcare facility use of ICD-10 codes for culture-confirmed candidemia cases detected by active public health surveillance during 2019–2020. Most cases (56%) did not receive a candidiasis code, suggesting that studies relying on ICD-10 codes likely underestimate disease burden.

Phylogenomic comparison of Neisseria gonorrhoeae causing disseminated gonococcal infections and uncomplicated gonorrhea in Georgia, United States

Disseminated gonococcal infection (DGI) is a rare complication caused by the systemic dissemination of Neisseria gonorrhoeae (Ng) to normally sterile anatomical sites. Little is known about the genetic diversity of DGI gonococcal strains and how they relate to other gonococcal strains causing uncomplicated mucosal infections. We used whole genome sequencing to characterize DGI isolates (n = 30) collected from a surveillance system in Georgia (GA), USA during 2017-2020 to understand phylogenetic clustering among DGI as well as uncomplicated uro-and-extragenital gonococcal (UGI) isolates (n = 110) collected in Fulton County, GA during 2017-2019. We also investigated the presence or absence of genetic markers related to antimicrobial resistance (AMR) as well as surveyed the genomes for putative virulence genetic factors associated with normal human-serum (NHS) resistance that might facilitate DGI. We found that DGI strains demonstrated significant genetic variability similar to the population structure of isolates causing UGI, with sporadic incidences of geographically clustered DGI strains. DGI isolates contained various AMR markers and genetic mechanisms associated with NHS resistance. DGI isolates had a higher frequency of the porB1A allele compared with UGI (67% vs. 9%, p &lt; 0.0001); however, no single NHS resistance marker was found in all DGI isolates. Continued DGI surveillance with genome-based characterization of DGI isolates is necessary to better understand specific factors that promote systemic dissemination.

Impact of 13-Valent Pneumococcal Conjugate Vaccine on Invasive Pneumococcal Disease Among Adults With HIV-United States, 2008-2018

BACKGROUND

People with HIV (PWH) are at increased risk for invasive pneumococcal disease (IPD). Thirteen-valent pneumococcal conjugate vaccine (PCV13) was recommended for use in US children in 2010 and for PWH aged 19 years or older in 2012. We evaluated the population-level impact of PCV13 on IPD among PWH and non-PWH aged 19 years or older.

METHODS

We identified IPD cases from 2008 to 2018 through the Active Bacterial Core surveillance platform. We estimated IPD incidence using the National HIV Surveillance System and US Census Bureau data. We measured percent changes in IPD incidence from 2008 to 2009 to 2017-2018 by HIV status, age group, and vaccine serotype group, including serotypes in recently licensed 15-valent (PCV15) and 20-valent (PCV20) PCVs.

RESULTS

In 2008-2009 and 2017-2018, 8.4% (552/6548) and 8.0% (416/5169) of adult IPD cases were among PWH, respectively. Compared with non-PWH, a larger proportion of IPD cases among PWH were in adults aged 19-64 years (94.7%-97.4% vs. 56.0%-60.1%) and non-Hispanic Black people (62.5%-73.0% vs. 16.7%-19.2%). Overall and PCV13-type IPD incidence in PWH declined by 40.3% (95% confidence interval: -47.7 to -32.3) and 72.5% (95% confidence interval: -78.8 to -65.6), respectively. In 2017-2018, IPD incidence was 16.8 (overall) and 12.6 (PCV13 type) times higher in PWH compared with non-PWH; PCV13, PCV15/non-PCV13, and PCV20/non-PCV15 serotypes comprised 21.5%, 11.2%, and 16.5% of IPD in PWH, respectively.

CONCLUSIONS

Despite reductions post-PCV13 introduction, IPD incidence among PWH remained substantially higher than among non-PWH. Higher-valent PCVs provide opportunities to reduce remaining IPD burden in PWH.

Clinical Characteristics, Healthcare Utilization, and Outcomes among Patients in a Pilot Surveillance System for Invasive Mold Disease—Georgia, United States, 2017–2019

Background

Invasive mold diseases (IMD) cause severe illness, but public health surveillance data are lacking. We describe data collected from a laboratory-based, pilot IMD surveillance system.

Methods

During 2017–2019, the Emerging Infections Program conducted active IMD surveillance at three Atlanta-area hospitals. We ascertained potential cases by reviewing histopathology, culture, and Aspergillus galactomannan results and classified patients as having an IMD case (based on European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group [MSG] criteria) or a non-MSG IMD case (based on the treating clinician’s diagnosis and use of mold-active antifungal therapy). We described patient features and compared patients with MSG versus non-MSG IMD cases.

Results

Among 304 patients with potential IMD, 104 (34.2%) met an IMD case definition (41 MSG, 63 non-MSG). The most common IMD types were invasive aspergillosis (n = 66, 63.5%), mucormycosis (n = 8, 7.7%), and fusariosis (n = 4, 3.8%); the most frequently affected body sites were pulmonary (n = 66, 63.5%), otorhinolaryngologic (n = 17, 16.3%), and cutaneous/deep tissue (n = 9, 8.7%). Forty-five (43.3%) IMD patients received intensive care unit-level care, and 90-day all-cause mortality was 32.7%; these outcomes did not differ significantly between MSG and non-MSG IMD patients.

Conclusions

IMD patients had high mortality rates and a variety of clinical presentations. Comprehensive IMD surveillance is needed to assess emerging trends, and strict application of MSG criteria for surveillance might exclude &gt; one-half of clinically significant IMD cases.

Surveillance for Disseminated Gonococcal Infections, Active Bacterial Core surveillance (ABCs) - United States, 2015-2019

BACKGROUND

Disseminated gonococcal infections (DGI) are thought to be uncommon; surveillance is limited and case reports are analyzed retrospectively or in case clusters. We describe the population-level burden of culture-confirmed DGI through the Active Bacterial Core surveillance (ABCs) system.

METHODS

During 2015-2016, retrospective surveillance was conducted among residents in two ABCs areas and prospectively in three ABCs areas during 2017-2019. A DGI case was defined as isolation of Neisseria gonorrhoeae (Ng) from a normally sterile site. A case report form was completed for each case and antimicrobial susceptibility testing (AST) was performed on available isolates.

RESULTS

During 2015-2019, 77 DGI cases were identified (~a rate of 0.13 cases per 100,000 population) and accounted for 0.06% of all reported gonorrhea cases in the three surveillance areas. Most DGI cases were male (64%), non-Hispanic Black (68%), and ranged from 16-67 years; blood (55%) and joint (40%) were the most common sterile sites. Among 29 isolates with AST results during 2017-2019, all were susceptible to ceftriaxone.

CONCLUSIONS

DGI is an infrequent complication of Ng; since Ng can quickly develop antimicrobial resistance, continued DGI surveillance, including monitoring trends in antimicrobial susceptibility, could help inform DGI treatment recommendations.

70. Changes in Invasive Pneumococcal Disease among Adults Living with HIV Following Introduction of 13-Valent Pneumococcal Conjugate Vaccine, 2008–2018

Background

People living with HIV (PLHIV) are at increased risk of invasive pneumococcal disease (IPD). The 13-valent pneumococcal conjugate vaccine (PCV13) was recommended for children in 2010, and for immunocompromised adults (including PLHIV) in series with 23-valent polysaccharide vaccine (PPSV23) in 2012. We evaluated changes in IPD incidence in adults ≥19 years old by HIV status after PCV13 introduction and proportion of remaining IPD due to serotypes included in the 15- (PCV15) and 20-valent (PCV20) conjugate vaccines expected to be licensed in 2021.

Methods

IPD cases were identified through CDC’s Active Bacterial Core surveillance (ABCs). HIV status was obtained from medical records. Isolates were serotyped by Quellung reaction, or whole-genome sequencing and grouped into PCV13-types, PPV11-types (unique to PPSV23), or non-vaccine types. We estimated IPD incidence (cases per 100,000 people) using national projections of ABCs cases as numerators and national case-based HIV surveillance (PLHIV) or US census data (non-PLHIV) as denominators. We compared IPD incidence in 2011–12 and 2017–18 to pre-PCV13 baseline (2008–09) by serotype groups. We assessed the proportion of IPD due to serotypes included in PCV15 and PCV20.

Results

Overall IPD incidence at baseline was 306.7 for PLHIV and 15.2 for non-PLHIV. From baseline to 2017–18, IPD incidence declined in PLHIV (-40.3%; 95% CI: -47.7, -32.3%) and non-PLHIV (-28.2%; 95% CI: -30.9, -25.5%). The largest reductions were in PCV13-type IPD during both periods (-44.2% for PLHIV and -42.2% for non-PLHIV in 2011–12; -72.5% for PLHIV and -62.2% for non-PLHIV in 2017–18) compared to baseline (Figures 1, 2). In 2017–2018, overall IPD and PCV13-type rates were 16.8 (95% CI: 15.1, 18.5) and 12.6 (95% CI: 9.9, 15.3) times as high in PLHIV vs non-PLHIV, respectively; PCV13, PCV15/non-PCV13, and PCV20/non-PCV15 serotypes comprised 21.5%, 11.2% and 16.5% of IPD in PLHIV.

IPD incidence rates among adults aged ≥19 years old by serotype group in PLHIV, 2008–2018

IPD incidence rates among adults aged ≥19 years old by serotype group in non-PLHIV, 2008–2018

Conclusion

IPD rates declined significantly in both PLHIV and non-PLHIV during the study period due to reductions in PCV13-type IPD; however, IPD rates remained 17-fold higher in PLHIV compared to non-PLHIV, mainly due to non-PCV13 types. Higher-valent pneumococcal conjugate vaccines provide opportunities to reduce some of the remaining IPD burden in PLHIV.

Disclosures

William Schaffner, MD, VBI Vaccines (Consultant) Lee Harrison, MD, GSK, Merck, Pfizer, Sanofi Pasteur (Consultant)

1299. Epidemiology of Invasive Pneumococcal Disease (IPD) in the United States 2011-2019

Background

Thirteen-valent pneumococcal conjugate vaccine (PCV13) was recommended for U.S. children aged &lt; 5 years in February 2010 and recommended in series with 23-valent pneumococcal polysaccharide vaccine (PPSV23) for adults aged ≥ 65 years in 2014. PCV13 has led to dramatic reductions in invasive pneumococcal disease (IPD) burden. New, higher valency PCVs (PCV15, PCV20) are expected to be licensed for adults in late 2021. We examined remaining PCV13-type IPD among children and adults and assessed IPD burden potentially preventable through PCV15 and PCV20 use.

Methods

IPD cases (isolation of pneumococcus from sterile sites) were identified through CDC’s Active Bacterial Core surveillance during 1998–2019. Isolates were serotyped by Quellung or whole genome sequencing. Incidence rates (cases/100,000) were calculated using U.S. Census Bureau population denominators.

Results

After introduction of PCV13 in children, by 2013–2014, PCV13-type IPD declined 89% (from 15 to 2 cases/100,000) in children age &lt; 5 years and 67% (from 19 to 7 cases/100,000) in adults age ≥ 65 years. During 2014–2019, rates of PCV13-type IPD in children and adults remained stable. In 2018–2019, among children age &lt; 5 years, serotypes 3, 19F, 19A, and 6C accounted for most of the remaining PCV13-type IPD (46%, 32%, 14% and 4% respectively) (Figure 1). Among adults age ≥ 65 years, serotypes 3, 6C, 19A, and 19F accounted for most of the remaining PCV13-type IPD (62%, 12%, 10%, and 9% respectively) (Figure 1). During 2015–2019, rates of PCV15 and PCV20-type IPD have remained stable. In 2018–2019, among adults age ≥ 65 years, PCV15 non-PCV13-type IPD rates were 3.6 cases per 100,000 and accounted for 15% of all IPD. PCV20 non-PCV13-type IPD rates were 6.8 cases per 100,000 and accounted for 29% of all IPD (Figure 2). Among children age &lt; 5 years, PCV15 non-PCV13-type IPD rates were 1.6 cases per 100,000 and accounted for 17% of all IPD. PCV20 non-PCV13-type IPD rates were 2.8 cases per 100,000 and accounted for 39% of all IPD (Figure 2).

Figure 1. Incidence rates of IPD among children &lt; 5 years old, by pneumococcal conjugate vaccine type and individual PCV13 serotypes, 2011–2019

Conclusion

Following the dramatic reductions after PCV13 introduction, PCV13-type IPD has remained stable during the past five years. There are opportunities to prevent an additional 30% IPD burden among adults through new PCV use.

Disclosures

William Schaffner, MD, VBI Vaccines (Consultant) Lee Harrison, MD, GSK, Merck, Pfizer, Sanofi Pasteur (Consultant)

Brucellosis Initially Misidentified as Ochrobactrum anthropi Bacteremia: A Case Report and Review of the Literature

Automated identification systems may misidentify Brucella, the causative agent of brucellosis, which may be re-emerging in the United States as the result of an expanding feral swine population. We present a case of Brucella suis likely associated with feral swine exposure that was misidentified as Ochrobactrum anthropi, a phylogenetic relative.

Effectiveness of COVID-19 Vaccines in Preventing Hospitalization Among Adults Aged ≥65 Years - COVID-NET, 13 States, February-April 2021

Clinical trials of COVID-19 vaccines currently authorized for emergency use in the United States (Pfizer-BioNTech, Moderna, and Janssen [Johnson & Johnson]) indicate that these vaccines have high efficacy against symptomatic disease, including moderate to severe illness (1-3). In addition to clinical trials, real-world assessments of COVID-19 vaccine effectiveness are critical in guiding vaccine policy and building vaccine confidence, particularly among populations at higher risk for more severe illness from COVID-19, including older adults. To determine the real-world effectiveness of the three currently authorized COVID-19 vaccines among persons aged ≥65 years during February 1-April 30, 2021, data on 7,280 patients from the COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) were analyzed with vaccination coverage data from state immunization information systems (IISs) for the COVID-NET catchment area (approximately 4.8 million persons). Among adults aged 65-74 years, effectiveness of full vaccination in preventing COVID-19-associated hospitalization was 96% (95% confidence interval [CI] = 94%-98%) for Pfizer-BioNTech, 96% (95% CI = 95%-98%) for Moderna, and 84% (95% CI = 64%-93%) for Janssen vaccine products. Effectiveness of full vaccination in preventing COVID-19-associated hospitalization among adults aged ≥75 years was 91% (95% CI = 87%-94%) for Pfizer-BioNTech, 96% (95% CI = 93%-98%) for Moderna, and 85% (95% CI = 72%-92%) for Janssen vaccine products. COVID-19 vaccines currently authorized in the United States are highly effective in preventing COVID-19-associated hospitalizations in older adults. In light of real-world data demonstrating high effectiveness of COVID-19 vaccines among older adults, efforts to increase vaccination coverage in this age group are critical to reducing the risk for COVID-19-related hospitalization.

Epidemiology of Invasive Haemophilus influenzae Serotype a Disease-United States, 2008-2017

BACKGROUND

Haemophilus influenzae serotype a (Hia) can cause invasive disease similar to serotype b; no Hia vaccine is available. We describe the epidemiology of invasive Hia disease in the United States overall and specifically in Alaska during 2008-2017.

METHODS

Active population- and laboratory-based surveillance for invasive Hia disease was conducted through Active Bacterial Core surveillance sites and from Alaska statewide invasive bacterial disease surveillance. Sterile-site isolates were serotyped via slide agglutination or real-time polymerase chain reaction. Incidences in cases per 100 000 were calculated.

RESULTS

From 2008 to 2017, an estimated average of 306 invasive Hia disease cases occurred annually in the United States (estimated annual incidence: 0.10); incidence increased by an average of 11.1% annually. Overall, 42.7% of cases were in children aged <5 years (incidence: 0.64), with highest incidence among children aged <1 year (1.60). Case fatality was 7.8% overall and was highest among adults aged ≥65 years (15.1%). Among children aged <5 years, the incidence was 17 times higher among American Indian and Alaska Native (AI/AN) children (8.29) than among children of all other races combined (0.49). In Alaska, incidences among all ages (0.68) and among children aged <1 year (24.73) were nearly 6 and 14 times higher, respectively, than corresponding US incidences. Case fatality in Alaska was 10.2%, and the vast majority (93.9%) of cases occurred among AI/AN.

CONCLUSIONS

Incidence of invasive Hia disease has increased since 2008, with the highest burden among AI/AN children. These data can inform prevention strategies, including Hia vaccine development.

The landscape of candidemia during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic has resulted in unprecedented healthcare challenges, and COVID-19 has been linked to secondary infections. Candidemia, a fungal healthcare-associated infection, has been described in patients hospitalized with severe COVID-19. However, studies of candidemia and COVID-19 co-infection have been limited in sample size and geographic scope. We assessed differences in patients with candidemia with and without a COVID-19 diagnosis.

METHODS

We conducted a case-level analysis using population-based candidemia surveillance data collected through the Centers for Disease Control and Prevention's Emerging Infections Program during April-August 2020 to compare characteristics of candidemia patients with and without a positive test for COVID-19 in the 30 days before their Candida culture using chi-square or Fisher exact tests.

RESULTS

Of the 251 candidemia patients included, 64 (25.5%) were positive for SARS-CoV-2. Liver disease, solid organ malignancies, and prior surgeries were each >3 times more common in patients without COVID-19 co-infection, whereas intensive care unit-level care, mechanical ventilation, having a central venous catheter, and receipt of corticosteroids and immunosuppressants were each >1.3 times more common in patients with COVID-19. All cause in-hospital fatality was two times higher among those with COVID-19 (62.5%) than without (32.1%).

CONCLUSIONS

One quarter of candidemia patients had COVID-19. These patients were less likely to have certain underlying conditions and recent surgery commonly associated with candidemia and more likely to have acute risk factors linked to COVID-19 care, including immunosuppressive medications. Given the high mortality, it is important for clinicians to remain vigilant and take proactive measures to prevent candidemia in patients with COVID-19.

Treatment Practices for Adults with Candidemia at Nine Active Surveillance Sites - United States, 2017-2018

BACKGROUND

Candidemia is a common opportunistic infection causing substantial morbidity and mortality. Because of an increasing proportion of non-albicans Candida species and rising antifungal drug resistance, the Infectious Diseases Society of America (IDSA) changed treatment guidelines in 2016 to recommend echinocandins over fluconazole as first-line treatment for adults with candidemia. We describe candidemia treatment practices and adherence to the updated guidelines.

METHODS

During 2017-2018, the Emerging Infections Program conducted active population-based candidemia surveillance at nine U.S. sites using a standardized case definition. We assessed factors associated with initial antifungal treatment for the first candidemia case among adults using multivariable logistic regression models. To identify instances of potentially inappropriate treatment, we compared the first antifungal drug received with species and antifungal susceptibility testing (AFST) results from initial blood cultures.

RESULTS

Among 1,835 patients who received antifungal treatment, 1,258 (68.6%) received an echinocandin and 543 (29.6%) received fluconazole as initial treatment. Cirrhosis (adjusted odds ratio = 2.06, 95% confidence interval: 1.29-3.29) was the only underlying medical condition significantly associated with initial receipt of an echinocandin (versus fluconazole). Over half (n = 304, 56.0%) of patients initially treated with fluconazole grew a non-albicans species. Among 265 patients initially treated with fluconazole and with fluconazole AFST results, 28 (10.6%) had a fluconazole-resistant isolate.

CONCLUSIONS

A substantial proportion of patients with candidemia were initially treated with fluconazole, resulting in potentially inappropriate treatment for those involving non-albicans or fluconazole-resistant species. Reasons for non-adherence to IDSA guidelines should be evaluated, and clinician education is needed.

Multistate, Population-Based Distributions of Candidate Vaccine Targets, Clonal Complexes, and Resistance Features of Invasive Group B Streptococci Within the United States, 2015-2017

BACKGROUND

Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and meningitis and an important cause of invasive infections in pregnant and nonpregnant adults. Vaccines targeting capsule polysaccharides and common proteins are under development.

METHODS

Using whole genome sequencing, a validated bioinformatics pipeline, and targeted antimicrobial susceptibility testing, we characterized 6340 invasive GBS isolates recovered during 2015-2017 through population-based Active Bacterial Core surveillance (ABCs) in 8 states.

RESULTS

Six serotypes accounted for 98.4% of isolates (21.8% Ia, 17.6% V, 17.1% II, 15.6% III, 14.5% Ib, 11.8% IV). Most (94.2%) isolates were in 11 clonal complexes (CCs) comprised of multilocus sequence types identical or closely related to sequence types 1, 8, 12, 17, 19, 22, 23, 28, 88, 452, and 459. Fifty-four isolates (0.87%) had point mutations within pbp2x associated with nonsusceptibility to 1 or more β-lactam antibiotics. Genes conferring resistance to macrolides and/or lincosamides were found in 56% of isolates; 85.2% of isolates had tetracycline resistance genes. Two isolates carrying vanG were vancomycin nonsusceptible (minimum inhibitory concentration = 2 µg/mL). Nearly all isolates possessed capsule genes, 1-2 of the 3 main pilus gene clusters, and 1 of 4 homologous alpha/Rib family determinants. Presence of the hvgA virulence gene was primarily restricted to serotype III/CC17 isolates (465 isolates), but 8 exceptions (7 IV/CC452 and 1 IV/CC17) were observed.

CONCLUSIONS

This first comprehensive, population-based quantitation of strain features in the United States suggests that current vaccine candidates should have good coverage. The β-lactams remain appropriate for first-line treatment and prophylaxis, but emergence of nonsusceptibility warrants ongoing monitoring.

Burden of Candidemia in the United States, 2017

BACKGROUND

Candidemia is a common healthcare-associated bloodstream infection with high morbidity and mortality. There are no current estimates of candidemia burden in the United States (US).

METHODS

In 2017, the Centers for Disease Control and Prevention conducted active population-based surveillance for candidemia through the Emerging Infections Program in 45 counties in 9 states encompassing approximately 17 million persons (5% of the national population). Laboratories serving the catchment area population reported all blood cultures with Candida, and a standard case definition was applied to identify cases that occurred in surveillance area residents. Burden of cases and mortality were estimated by extrapolating surveillance area cases to national numbers using 2017 national census data.

RESULTS

We identified 1226 candidemia cases across 9 surveillance sites in 2017. Based on this, we estimated that 22 660 (95% confidence interval [CI], 20 210-25 110) cases of candidemia occurred in the US in 2017. Overall estimated incidence was 7.0 cases per 100 000 persons, with highest rates in adults aged ≥ 65 years (20.1/100 000), males (7.9/100 000), and those of black race (12.3/100 000). An estimated 3380 (95% CI, 1318-5442) deaths occurred within 7 days of a positive Candida blood culture, and 5628 (95% CI, 2465-8791) deaths occurred during the hospitalization with candidemia.

CONCLUSIONS

Our analysis highlights the substantial burden of candidemia in the US. Because candidemia is only one form of invasive candidiasis, the true burden of invasive infections due to Candida is higher. Ongoing surveillance can support future burden estimates and help assess the impact of prevention interventions.

The Changing Epidemiology of Candidemia in the United States: Injection Drug Use as an Increasingly Common Risk Factor-Active Surveillance in Selected Sites, United States, 2014-2017

BACKGROUND

Injection drug use (IDU) is a known, but infrequent risk factor on candidemia; however, the opioid epidemic and increases in IDU may be changing the epidemiology of candidemia.

METHODS

Active population-based surveillance for candidemia was conducted in selected US counties. Cases of candidemia were categorized as IDU cases if IDU was indicated in the medical records in the 12 months prior to the date of initial culture.

RESULTS

During 2017, 1191 candidemia cases were identified in patients aged >12 years (incidence: 6.9 per 100 000 population); 128 (10.7%) had IDU history, and this proportion was especially high (34.6%) in patients with candidemia aged 19-44. Patients with candidemia and IDU history were younger than those without (median age, 35 vs 63 years; P < .001). Candidemia cases involving recent IDU were less likely to have typical risk factors including malignancy (7.0% vs 29.4%; relative risk [RR], 0.2 [95% confidence interval {CI}, .1-.5]), abdominal surgery (3.9% vs 17.5%; RR, 0.2 [95% CI, .09-.5]), and total parenteral nutrition (3.9% vs 22.5%; RR, 0.2 [95% CI, .07-.4]). Candidemia cases with IDU occurred more commonly in smokers (68.8% vs 18.5%; RR, 3.7 [95% CI, 3.1-4.4]), those with hepatitis C (54.7% vs 6.4%; RR, 8.5 [95% CI, 6.5-11.3]), and in people who were homeless (13.3% vs 0.8%; RR, 15.7 [95% CI, 7.1-34.5]).

CONCLUSIONS

Clinicians should consider injection drug use as a risk factor in patients with candidemia who lack typical candidemia risk factors, especially in those with who are 19-44 years of age and have community-associated candidemia.

Use of Baricitinib in Patients With Moderate to Severe Coronavirus Disease 2019

Hyperinflammation is associated with increased mortality in coronavirus disease 2019 (COVID-19). In this retrospective, uncontrolled patient cohort with moderate -severe COVID-19, treatment with baricitinib plus hydroxychloroquine was associated with recovery in 11 of 15 patients. Baricitinib for the treatment of COVID-19 should be further investigated in randomized, controlled clinical trials.

Low but Increasing Prevalence of Reduced Beta-lactam Susceptibility Among Invasive Group B Streptococcal Isolates, US Population-Based Surveillance, 1998-2018

BACKGROUND

Invasive group B Streptococcus (iGBS) isolates with mutations in the pbp2x gene that encodes penicillin binding protein 2x can have reduced beta-lactam susceptibility (RBLS) when susceptible by Clinical and Laboratory Standards Institute (CLSI) criteria. We assessed the emergence and characteristics of RBLS strains in US iGBS isolates.

METHODS

We analyzed iGBS isolates from 8 multistate population-based surveillance sites from 1998 to 2018. During 1998-2014, phenotypic antimicrobial susceptibility was determined by broth microdilution; criteria for 6 antibiotics were used to identify RBLS, followed by whole-genome sequencing (WGS). WGS for all isolates was added in 2015; we used phenotypic and genotypic results of >2000 isolates to validate phenotypic RBLS criteria and genotypic predictions. Since 2016, WGS has been used to screen for RBLS with broth microdilution confirmation of predicted RBLS isolates.

RESULTS

Of 28 269 iGBS isolates, 28 (0.1%) were nonsusceptible by CLSI criteria; 137 (0.5%) met RBLS criteria. RBLS isolates were detected in all Active Bacterial Core surveillance sites. The RBLS proportion increased, especially since 2013 (odds ratio, 1.17; 95% CI, 1.03-1.32); the proportion that were nonsusceptible remained stable.

CONCLUSIONS

The RBSL proportion was low but increasing among US iGBS isolates. Ongoing monitoring is needed to detect emerging threats to prevention and treatment of GBS infections.

Outcomes of Immunocompromised Adults Hospitalized With Laboratory-confirmed Influenza in the United States, 2011-2015

BACKGROUND

Hospitalized immunocompromised (IC) adults with influenza may have worse outcomes than hospitalized non-IC adults.

METHODS

We identified adults hospitalized with laboratory-confirmed influenza during 2011-2015 seasons through CDC's Influenza Hospitalization Surveillance Network. IC patients had human immunodefiency virus (HIV)/AIDS, cancer, stem cell or organ transplantation, nonsteroid immunosuppressive therapy, immunoglobulin deficiency, asplenia, and/or other rare conditions. We compared demographic and clinical characteristics of IC and non-IC adults using descriptive statistics. Multivariable logistic regression and Cox proportional hazards models controlled for confounding by patient demographic characteristics, pre-existing medical conditions, influenza vaccination, and other factors.

RESULTS

Among 35 348 adults, 3633 (10%) were IC; cancer (44%), nonsteroid immunosuppressive therapy (44%), and HIV (18%) were most common. IC patients were more likely than non-IC patients to have received influenza vaccination (53% vs 46%; P < .001), and ~85% of both groups received antivirals. In multivariable analysis, IC adults had higher mortality (adjusted odds ratio [aOR], 1.46; 95% confidence interval [CI], 1.20-1.76). Intensive care was more likely among IC patients 65-79 years (aOR, 1.25; 95% CI, 1.06-1.48) and those >80 years (aOR, 1.35; 95% CI, 1.06-1.73) compared with non-IC patients in those age groups. IC patients were hospitalized longer (adjusted hazard ratio of discharge, 0.86; 95% CI, .83-.88) and more likely to require mechanical ventilation (aOR, 1.19; 95% CI, 1.05-1.36).

CONCLUSIONS

Substantial morbidity and mortality occurred among IC adults hospitalized with influenza. Influenza vaccination and antiviral administration could be increased in both IC and non-IC adults.

85. Characterization of Group B streptococcus Strains with Reduced Susceptibility to Beta-lactam Antibiotics, Active Bacterial Core Surveillance, 1998–2017

Background

In the United States, approximately 30,000 invasive group B Streptococcus (iGBS) infections occur annually; beta-lactam antibiotics (BL) are the first choice for prevention in young infants and treatment in all age groups. We obtained phenotypic and genotypic data for iGBS isolates from U.S. population-based surveillance sites to describe the emergence and characteristics of strains with reduced beta-lactam susceptibility (RS) over a 20-year period.

Methods

We analyzed RS iGBS isolates from eight Active Bacterial Core surveillance sites from 1998–2017. Through 2014, minimum inhibitory concentrations (MIC) for six BL were determined by broth microdilution, followed by whole genome sequencing (WGS) of RS isolates exceeding pre-defined breakpoints (Table 1). In 2015, WGS and MIC testing were performed for all isolates. After 2015, all isolates underwent WGS. MIC testing was continued on approximately 25% of isolates; otherwise, only those with modified penicillin binding protein (PBP) 2x transpeptidase amino acid sequence types or suboptimal WGS (< 1 % of isolates) underwent MIC testing. Clinical information on RS cases was abstracted from medical charts.

Results

Of 26,058 out of 27,269 iGBS isolates (95.6%) tested to date, 107 (0.4%) exhibited RS, increasing from 0% in 1998 to a peak of 1.1% in 2016 (P< 0.05 for trend) (Figure 1). Seven (6.5%) RS strains were from infants aged < 90 days; the rest were from adults aged ≥30 years (Table 2). RS strains consisted of 52 PBP2x types with diverse susceptibility patterns (Table 1). Seven RS strains (6.5%) had wild-type (non-modified) PBP2x; all met the RS criteria based on a single cephalosporin with a confirmed (repeated) MIC value at the break point (Table 1). Compared to non-RS strains, RS strains were more common in patients who presented with cellulitis and osteomyelitis and with underlying conditions such as diabetes or chronic skin breakdown (Table 2). Of 82 (85.4%) patients with RS strains and additional clinical information, 8.3% had known prior GBS infection; 26.8% had known BL exposure in the preceding year.

Conclusion

Preliminary results show that RS increased in recent years; strains RS to penicillin and ampicillin remain low. Variable pbp2x mutations have emerged and predominant strains have not yet been identified.

Disclosures

Nisha B. Alden, MPH, CDC (Grant/Research Support) Lee Harrison, MD, Dynavax (Consultant)GSK (Consultant)Merck (Consultant)OMVax (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

1474. Impact of 13-valent Pneumococcal Conjugate Vaccine (PCV13) on Non-bacteremic Pneumococcal Pneumonia (NBPP) among Adults in the United States, 2013-2017

Background

PCV13 was recommended for U.S. children in 2010 and for adults ≥ 65 years in 2014. Vaccine coverage among adults ≥ 65 years was 43% in 2017. We evaluated PCV13 impact on NBPP among adults.

Methods

NBPP cases (clinically or radiographically confirmed pneumonia and a positive pneumococcal urine antigen test (PUAT) in a hospitalized adult aged ≥ 18 years) were identified at select hospitals in 10 sites within CDC’s Active Bacterial Core surveillance during 2013-2017. NBPP rates (per 100,000) were estimated using U.S. Census Bureau population denominators and adjusted for the proportion of pneumonia patients tested by PUAT and the number of pneumonia admissions in the catchment area.

Results

Between 2013 and 2017, 4,430 NBPP cases were identified. Adults aged ≥ 65 years accounted for 49% of cases. Case fatality rate was 6%. From 2013 to 2014, rates of NBPP declined from 153 to 90 (41% reduction, 95%CI 28%, 51%) in ≥ 65 year-olds; 60 to 40 (34% reduction, 95%CI 22%, 45%) in 50-64 year-olds; and 15 to 10 (36% reduction, 95%CI 25%, 47%) in 18-49 year-olds. From 2014 to 2017, rates of NBPP increased in all ages, but remained below 2013 rates (Figure).

Figure. Estimated Annual Non-Bacteremic Pneumococcal Pneumonia Incidence by Age Group, 2013–2017

Conclusion

Reductions in NBPP among adults were primarily due to indirect effects of PCV13 use in children, with no additional declines following PCV13 introduction for adults aged ≥ 65 years.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant) Nisha B. Alden, MPH, CDC (Grant/Research Support)

146. antifungal Susceptibility Patterns of candida Parapsilosis Bloodstream Isolates in the US, 2008–2018

Background

Multidrug resistant Candida is an increasing concern. C. parapsilosis in particular has decreased in vitro susceptibility to echinocandins. As a result, fluconazole had been favored for C. parapsilosis treatment. However, there is growing concern about increasing azole resistance among Candida species. We report on antifungal susceptibility patterns of C. parapsilosis in the US from 2008 through 2018.

Methods

Active, population-based surveillance for candidemia through the Centers for Disease Control and Prevention’s (CDC) Emerging Infections Program was conducted between 2008–2018, eventually encompassing 9 states (GA, MD,OR, TN, NY, CA, CO, MN, NM). Each incident isolate was sent to the CDC for species confirmation and antifungal susceptibility testing (AFST). Frequency of resistance was calculated and stratified by year and state using SAS 9.4

Results

Of the 8,704 incident candidemia isolates identified, 1,471 (15%) were C. parapsilosis; the third most common species after C. albicans and C. glabrata. AFST results were available for 1,340 C. parapsilosis isolates. No resistance was detected to caspofungin (MIC₅₀ 0.25) or micafungin (MIC₅₀ 1.00) with only one (< 1%) isolate resistant to anidulafungin (MIC₅₀ 1.00). In contrast, 84 (6.3%) isolates were resistant to fluconazole and another 44 (3.3%) isolates had dose-dependent susceptibility to fluconazole (MIC₅₀ 1.00). Fluconazole resistance increased sharply from an average of 4% during 2008–2014 to a peak of 14% in 2016 with a subsequent decline to 6% in 2018 (see figure). Regional variation is also observed with fluconazole resistance ranging from 0% (CO, MN, NM) to 42% (NY) of isolates by site.

Conclusion

The recent marked increase in fluconazole resistance among C. parapsilosis highlights this pathogen as an emerging drug resistant pathogen of concern and the need for ongoing antifungal resistance surveillance among Candida species. Our data support the empiric use of echinocandins for C. parapsilosis bloodstream infections and underscore the need to obtain AFST prior to fluconazole treatment. Furthermore, regional variation in fluconazole resistance emphasizes the importance of understanding local Candida susceptibility patterns.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

180. Impact of Pneumococcal Conjugative Vaccine on Antibiotic Resistant Invasive Pneumococcal Disease in the United States

Background

Antibiotic-nonsusceptible invasive pneumococcal disease (NS-IPD) in the United States declined dramatically following the introduction of pneumococcal conjugative vaccines (7-valent, PCV7 in 2000, replaced by the 13-valent, PCV13 in 2010). We evaluated the long-term impact of PCV13 on NS-IPD.

Methods

IPD cases were identified through CDC’s Active Bacterial Core surveillance during 2005−2018. We applied 2012 Clinical and Laboratory Standards Institute breakpoints to minimum inhibitory concentrations determined by broth microdilution (2005−2014) or whole genome sequencing (2015−2018) and classified non-susceptible isolates as those intermediate or resistant to ≥1 antibiotic class. Isolates were serotyped and classified as PCV13 or non-vaccine type (NVT). Incidence rates (cases per 100,000) were calculated using United States Census Bureau population denominators.

Results

From 2005 to 2018, NS IPD incidence decreased from 8.5 to 3.2 among children < 5 years old and from 13.0 to 9.4 among adults ≥ 65 years old. Incidence of vaccine-type NS-IPD decreased in all age groups (Figure 1), while incidence of NVT NS-IPD increased in all age groups (Figure 2). The greatest absolute increase in NVT NS-IPD occurred among adults ≥ 65 years from 4.7 in 2005 to 7.2 in 2018. PCV13 serotypes contributed to 62% of NS-IPD (36% of NS-IPD caused by serotype 19A alone) in 2005−2009, and 27% of NS-IPD in 2014−18 (8% of NS-IPD caused by 19A). During 2014–18, NVTs 35B (11%), 33F (9%), 22F (9%), and 15A (9%) were the most common NS-IPD serotypes.

Figure 1. Incidence of vaccine type antibiotic non-susceptible invasive pneumococcal disease by age group, 2005−2018.

Figure 2. Incidence of non-vaccine type antibiotic non-susceptible invasive pneumococcal disease by age group, 2005−2018.

Conclusion

NS-IPD incidence decreased following PCV13 use in the United States, driven by reductions in PCV13 serotypes. Recent increases in NVT NS-IPD, most pronounced among older adults, have started to erode PCV impact on NS-IPD. PCVs in development that contain serotypes 22F and 33F could help to further reduce NS-IPD.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

1470. Epidemiology of Invasive Pneumococcal Disease (IPD) Following 18 years of Pneumococcal Conjugate Vaccine (PCV) Use in the United States

Background

PCVs have been recommended for U.S. children since 2000. A 7-valent vaccine (PCV7) was introduced in 2000. This was replaced by a 13-valent vaccine (PCV13) in 2010. PCV13 was also recommended for adults aged ≥ 65 years in August 2014. We evaluated PCV impact on IPD.

Methods

IPD cases (isolation of pneumococcus from sterile sites) were identified through CDC’s Active Bacterial Core surveillance during 1998-2018. Isolates were serotyped by Quellung or whole genome sequencing and classified as PCV13-type and non-vaccine-type (NVT). Incidence rates (cases/100,000) were calculated using U.S. Census Bureau population denominators.

Results

From 1998 through 2018, overall IPD rates among children aged < 5 years decreased by 93% (from 95 to 7 cases/100,000). PCV13-type IPD decreased by 98% (from 88 to 2 cases/100,000). Among adults aged ≥ 65 years, overall IPD rates decreased by 60% (from 61 to 25 cases/100,000). PCV13-type IPD rates declined 86% (from 46 to 7 cases/100,000). Declines were most dramatic in the years following PCV7 introduction, with additional declines after PCV13 introduction in children (Figures 1 and 2). Serotypes 3, 19A, and 19F caused most of the remaining PCV13-type IPD. NVT IPD rates did not change significantly among children. Among adults aged 50-64 years, NVT IPD increased by 83% (from 6 to 12 cases/100,000) (p< 0.01). Among adults aged ≥ 65 years, NVT IPD increased by 22% (from 15 to 18 cases/100,000) (p< 0.01). The most common NVTs in 2018 were 22F (10% of all IPD), 9N (7%) and 15A (5%). Among children, the proportion of cases with meningitis increased from 5% to 14% (p< 0.01), and the proportion with pneumonia/empyema increased from 17% to 31% (p< 0.01). Among adults, the proportion of cases with meningitis did not change (3%), while the proportion with pneumonia/empyema increased from 72% to 76% (p=0.01).

Figure 1: Incidence of invasive pneumococcal disease among children aged < 5 years, 1998-2018

Figure 2: Incidence of invasive pneumococcal disease among adults aged ≥ 65 years, 1998-2018

Conclusion

Overall IPD incidence among children and adults decreased following PCV introduction for children, driven primarily by reductions in PCV-type IPD. NVT IPD increased in older adults, but these increases did not eliminate reductions from PCV13-type IPD.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

1424. Factors Associated with Failure to Clear Candidemia Infection: Surveillance Data from Eight States, 2017

Background

Candidemia is a bloodstream infection commonly associated with high morbidity and mortality. Failure to clear candidemia can lengthen hospitalization and treatment. Factors associated with candidemia clearance are unknown.

Methods

We analyzed 2017 candidemia surveillance data from the Centers for Disease Control and Prevention’s Emerging Infections Program. Data from eight sites (counties in California, Colorado, Georgia, Minnesota, New Mexico, New York, Oregon, and Tennessee) were included. Clearance was defined as having a blood culture negative for Candida ≤30 days after initial culture date (ICD). Cases with unknown clearance, unknown survival outcome, or death ≤30 days of ICD were excluded. Demographic and clinical factors associated with clearance were assessed with bivariate analysis using chi-square tests and multivariable logistic regression to calculate adjusted odds ratios (aOR) using backward selection (p-value&lt; 0.10).

Results

Of 1,024 candidemia cases, 737 were included and 582 (79%) demonstrated clearance, of which 79% had evidence of clearance ≤5 days after ICD. In bivariate analysis, clearance was associated with central venous catheter (CVC) ≤2 days before ICD, CVC removal ≤7 days after ICD, and systemic antifungal medication within 14 days before ICD. Clearance was inversely associated with black race and admission from another hospital. In multivariable analysis, only race and admission from another hospital were significant predictors; age, sex, and CVC presence and subsequent removal were also retained for their clinical relevance. In the final model, clearance was less likely among black patients (aOR 0.51, 95% confidence interval [CI] 0.29-0.91) and those admitted from another hospital (aOR 0.28, 95% CI 0.11-0.75).

Table 1. Bivariate associations for select variables between individuals with documented candidemia clearance and those without documented clearance in eight Emerging Infections Program surveillance sites, 2017

Conclusion

We found failure to clear candidemia infection to be associated with black race and prior hospital exposure, but not other factors previously shown to be associated (e.g., comorbidities, CVC presence). These associations could reflect illness severity, access to care, or other obstacles to effective treatment. Additional research is needed to investigate these associations further and identify other factors (e.g., treatment type and timing) to improve outcomes.

Disclosures

All Authors: No reported disclosures

912. Beyond the Usual Suspects in Invasive Mold Infections: Public Health Surveillance Identifies Clinical Diversity

Background

Invasive mold infections (IMI) such as aspergillosis and mucormycosis are often fatal among immunocompromised patients and cause high-profile outbreaks. Public health surveillance for IMI is challenging; most epidemiologic studies are limited to transplant and cancer patients at greatest risk of IMI. The established Mycoses Study Group (MSG) case definition is useful for clinical trials but lacks sensitivity. To address these challenges, we created IMI surveillance within the Georgia Emerging Infections Program. Here, we describe cases identified through this system, using both the MSG criteria and a novel, more sensitive surveillance case definition.

Methods

To identify potential IMI cases, we captured 2,363 positive fungal laboratory results, including cultures, histopathology, and galactomannan tests, within a 60-day window at three large Atlanta hospitals during April 2018–March 2019. We excluded yeast and dimorphic fungi, hair and nail specimens, and cystic fibrosis patients. Potential cases underwent chart review and were classified by 2 physicians as proven, probable, or non-case according to MSG criteria. Cases that partially met MSG probable criteria and included antifungal treatment were classified as surveillance cases; definitions were mutually exclusive (Fig 1).

Results

Of 120 potential IMI cases, 46 (38%) met an IMI case definition: 8 proven, 9 probable, and 29 surveillance cases (Fig 2). Of cases, 14 (30%) involved transplant or cancer in the previous year; 8 of these were proven or probable cases. IMI presented primarily as sinusitis among proven cases (50%), and pulmonary infections among probable (56%) and surveillance (45%) cases. Most surveillance cases were caused by Aspergillus spp. (72%) and accounted for all 5 cutaneous IMI (fig 3). Over 80% of cases vs. 10% of non-cases had antifungal treatment.

Conclusion

Of IMI cases identified, nearly two thirds had evidence of infection but did not meet an MSG case definition. MSG captured over half of transplant and cancer-associated cases, but these were uncommon overall, revealing most IMI lack classical risk factors. A more sensitive surveillance case definition can capture a broader spectrum of IMI patients receiving antifungal treatment to help guide clinical and public health interventions.

Disclosures

All Authors: No reported disclosures

Absence of mgrB Alleviates Negative Growth Effects of Colistin Resistance in Enterobacter cloacae

Colistin is an important last-line antibiotic to treat highly resistant Enterobacter infections. Resistance to colistin has emerged among clinical isolates but has been associated with a significant growth defect. Here, we describe a clinical Enterobacter isolate with a deletion of mgrB, a regulator of colistin resistance, leading to high-level resistance in the absence of a growth defect. The identification of a path to resistance unrestrained by growth defects suggests colistin resistance could become more common in Enterobacter.

Transmission Dynamics and Microevolution of Neisseria meningitidis During Carriage and Invasive Disease in High School Students in Georgia and Maryland, 2006-2007

BACKGROUND

The mechanisms by which Neisseria meningitidis cause persistent human carriage and transition from carriage to invasive disease have not been fully elucidated.

METHODS

Georgia and Maryland high school students were sampled for pharyngeal carriage of N. meningitidis during the 2006-2007 school year. A total of 321 isolates from 188 carriers and all 67 invasive disease isolates collected during the same time and from the same geographic region underwent whole-genome sequencing. Core-genome multilocus sequence typing was used to compare allelic profiles, and direct read mapping was used to study strain evolution.

RESULTS

Among 188 N. meningitidis culture-positive students, 98 (52.1%) were N. meningitidis culture positive at 2 or 3 samplings. Most students who were positive at >1 sampling (98%) had persistence of a single strain. More than a third of students carried isolates that were highly genetically related to isolates from other students in the same school, and occasional transmission within the same county was also evident. The major pilin subunit gene, pilE, was the most variable gene, and no carrier had identical pilE sequences at different time points.

CONCLUSION

We found strong evidence of local meningococcal transmission at both the school and county levels. Allelic variation within genes encoding bacterial surface structures, particularly pilE, was common.

Evaluation of viral co-infections among patients with community-associated Clostridioides difficile infection

We assessed viral co-infections in 155 patients with community-associated Clostridioides difficile infection in five U.S. sites during December 2012–February 2013. Eighteen patients (12%) tested positive for norovirus (n = 10), adenovirus (n = 4), rotavirus (n = 3), or sapovirus (n = 1). Co-infected patients were more likely than non-co-infected patients to have nausea or vomiting (56% vs 31%; p = 0.04), suggesting that viral co-pathogens contributed to symptoms in some patients. There were no significant differences in prior healthcare or medication exposures or in CDI complications.

Toxin Enzyme Immunoassays Detect Clostridioides difficile Infection With Greater Severity and Higher Recurrence Rates

BACKGROUND

Few data suggest that Clostridioides difficile infections (CDIs) detected by toxin enzyme immunoassay (EIA) are more severe and have worse outcomes than those detected by nucleic acid amplification tests (NAATs) only. We compared toxin- positive and NAAT-positive-only CDI across geographically diverse sites.

METHODS

A case was defined as a positive C. difficile test in a person ≥1 year old with no positive tests in the prior 8 weeks. Cases were detected during 2014-2015 by a testing algorithm (specimens initially tested by glutamate dehydrogenase and toxin EIA; if discordant results, specimens were reflexed to NAAT) and classified as toxin positive or NAAT positive only. Medical charts were reviewed. Multivariable logistic regression models were used to compare CDI-related complications, recurrence, and 30-day mortality between the 2 groups.

RESULTS

Of 4878 cases, 2160 (44.3%) were toxin positive and 2718 (55.7%) were NAAT positive only. More toxin-positive than NAAT-positive-only cases were aged ≥65 years (48.2% vs 38.0%; P < .0001), had ≥3 unformed stools for ≥1 day (43.9% vs 36.6%; P < .0001), and had white blood cell counts ≥15 000 cells/µL (31.4% vs 21.4%; P < .0001). In multivariable analysis, toxin positivity was associated with recurrence (adjusted odds ratio [aOR], 1.89; 95% confidence interval [CI], 1.61-2.23), but not with CDI-related complications (aOR, 0.91; 95% CI, .67-1.23) or 30-day mortality (aOR, 0.95; 95% CI, .73-1.24).

CONCLUSIONS

Toxin-positive CDI is more severe, but there were no differences in adjusted CDI-related complication and mortality rates between toxin-positive and NAAT-positive-only CDI that were detected by an algorithm that utilized an initial glutamate dehydrogenase screening test.

Clinical characteristics and adverse clinical outcomes of invasive Haemophilus influenzae serotype a cases - United States, 2011-2015

BACKGROUND

Incidence of invasive disease due to H. influenzae serotype a (Hia) increased an average of 13% annually from 2002-2015. We described clinical characteristics and adverse clinical outcomes of U.S. invasive Hia cases detected through multi-state surveillance during 2011-2015.

METHODS

Medical record data were abstracted for cases reported in eight jurisdictions conducting active population- and laboratory-based surveillance for invasive Hia disease across the United States. Isolates from sterile sites were serotyped by real-time polymerase chain reaction. Adverse clinical outcomes were defined as any possible complication of meningitis, bacteremic pneumonia, or bacteremia (including hearing loss, developmental delay, and speech delay, but excluding death), and were assessed at hospital discharge and one-year post-disease onset.

RESULTS

During 2011-2015, 190 Hia cases were reported to the eight participating sites; 169 (88.9%) had data abstracted. Many patients were aged <5 years (42.6%) or ≥65 years (20.7%). Meningitis was the most common clinical presentation among <1 year olds (71.4%); bacteremic pneumonia was the most common presentation among persons aged ≥50 years (78.7%). Overall, 95.9% of patients were hospitalized: among those hospitalized, 47.5% were admitted to an intensive care unit, and 6.2% died during hospitalization. At hospital discharge and one-year post-disease onset, adverse outcomes were identified in 17.7% and 17.8% of patients overall, and in 43.9% and 48.5% of patients with meningitis (primarily children).

CONCLUSIONS

Hia infection can cause severe disease requiring hospitalization and may also cause short- and long-term adverse clinical outcomes, especially among children. Novel vaccines could prevent morbidity and mortality.

Trends in U.S. Burden of Clostridioides difficile Infection and Outcomes

BACKGROUND

Efforts to prevent Clostridioides difficile infection continue to expand across the health care spectrum in the United States. Whether these efforts are reducing the national burden of C. difficile infection is unclear.

METHODS

The Emerging Infections Program identified cases of C. difficile infection (stool specimens positive for C. difficile in a person ≥1 year of age with no positive test in the previous 8 weeks) in 10 U.S. sites. We used case and census sampling weights to estimate the national burden of C. difficile infection, first recurrences, hospitalizations, and in-hospital deaths from 2011 through 2017. Health care-associated infections were defined as those with onset in a health care facility or associated with recent admission to a health care facility; all others were classified as community-associated infections. For trend analyses, we used weighted random-intercept models with negative binomial distribution and logistic-regression models to adjust for the higher sensitivity of nucleic acid amplification tests (NAATs) as compared with other test types.

RESULTS

The number of cases of C. difficile infection in the 10 U.S. sites was 15,461 in 2011 (10,177 health care-associated and 5284 community-associated cases) and 15,512 in 2017 (7973 health care-associated and 7539 community-associated cases). The estimated national burden of C. difficile infection was 476,400 cases (95% confidence interval [CI], 419,900 to 532,900) in 2011 and 462,100 cases (95% CI, 428,600 to 495,600) in 2017. With accounting for NAAT use, the adjusted estimate of the total burden of C. difficile infection decreased by 24% (95% CI, 6 to 36) from 2011 through 2017; the adjusted estimate of the national burden of health care-associated C. difficile infection decreased by 36% (95% CI, 24 to 54), whereas the adjusted estimate of the national burden of community-associated C. difficile infection was unchanged. The adjusted estimate of the burden of hospitalizations for C. difficile infection decreased by 24% (95% CI, 0 to 48), whereas the adjusted estimates of the burden of first recurrences and in-hospital deaths did not change significantly.

CONCLUSIONS

The estimated national burden of C. difficile infection and associated hospitalizations decreased from 2011 through 2017, owing to a decline in health care-associated infections. (Funded by the Centers for Disease Control and Prevention.).

Clinical Features and Outcomes of Immunocompromised Children Hospitalized With Laboratory-Confirmed Influenza in the United States, 2011-2015

BACKGROUND

Existing data on the clinical features and outcomes of immunocompromised children with influenza are limited.

METHODS

Data from the 2011-2012 through 2014-2015 influenza seasons were collected as part of the Centers for Disease Control and Prevention (CDC) Influenza Hospitalization Surveillance Network (FluSurv-NET). We compared clinical features and outcomes between immunocompromised and nonimmunocompromised children (<18 years old) hospitalized with laboratory-confirmed community-acquired influenza. Immunocompromised children were defined as those for whom ≥1 of the following applies: human immunodeficiency virus/acquired immunodeficiency syndrome, cancer, stem cell or solid organ transplantation, nonsteroidal immunosuppressive therapy, immunoglobulin deficiency, complement deficiency, asplenia, and/or another rare condition. The primary outcomes were intensive care admission, duration of hospitalization, and in-hospital death.

RESULTS

Among 5262 hospitalized children, 242 (4.6%) were immunocompromised; receipt of nonsteroidal immunosuppressive therapy (60%), cancer (39%), and solid organ transplantation (14%) were most common. Immunocompromised children were older than the nonimmunocompromised children (median, 8.8 vs 2.8 years, respectively; P < .001), more likely to have another comorbidity (58% vs 49%, respectively; P = .007), and more likely to have received an influenza vaccination (58% vs 39%, respectively; P < .001) and early antiviral treatment (35% vs 27%, respectively; P = .013). In multivariable analyses, immunocompromised children were less likely to receive intensive care (adjusted odds ratio [95% confidence interval], 0.31 [0.20-0.49]) and had a slightly longer duration of hospitalization (adjusted hazard ratio of hospital discharge [95% confidence interval], 0.89 [0.80-0.99]). Death was uncommon in both groups.

CONCLUSIONS

Immunocompromised children hospitalized with influenza received intensive care less frequently but had a longer hospitalization duration than nonimmunocompromised children. Vaccination and early antiviral use could be improved substantially. Data are needed to determine whether immunocompromised children are more commonly admitted with milder influenza severity than are nonimmunocompromised children.

Invasive Nontypeable Haemophilus influenzae Infection Among Adults With HIV in Metropolitan Atlanta, Georgia, 2008-2018

IMPORTANCE

Invasive nontypeable Haemophilus influenzae (NTHi) infection among adults is typically associated with bacteremic pneumonia. Nontypeable H influenzae is genetically diverse and clusters of infection are uncommon.

OBJECTIVE

To evaluate an increase in invasive NTHi infection from 2017-2018 among HIV-infected men who have sex with men in metropolitan Atlanta, Georgia.

DESIGN, SETTING, AND PARTICIPANTS

A population-based surveillance study with a cohort substudy and descriptive epidemiological analysis identified adults aged 18 years or older with invasive NTHi infection (isolation of NTHi from a normally sterile site) between January 1, 2008, and December 31, 2018 (final date of follow-up).

EXPOSURES

Time period, HIV status, and genetic relatedness (ie, cluster status) of available NTHi isolates.

MAIN OUTCOMES AND MEASURES

The primary outcome was incidence of invasive NTHi infection (from 2008-2016 and 2017-2018) among persons with HIV and compared with NTHi infection from 2008-2018 among those without HIV. The secondary outcomes were assessed among those aged 18 to 55 years with invasive NTHi infection and included epidemiological, clinical, and geographic comparisons by cluster status.

RESULTS

Among 553 adults with invasive NTHi infection (median age, 66 years [Q1-Q3, 48-78 years]; 52% male; and 38% black), 60 cases occurred among persons with HIV. Incidence of invasive NTHi infection from 2017-2018 among persons with HIV (41.7 cases per 100 000) was significantly greater than from 2008-2016 among those with HIV (9.6 per 100 000; P < .001) and from 2008-2018 among those without HIV (1.1 per 100 000; P < .001). Among adults aged 18 to 55 years with invasive NTHi infections from 2017-2018 (n = 179), persons with HIV (n = 31) were significantly more likely than those from 2008-2018 without HIV (n = 124) to be male (94% vs 49%, respectively; P < .001), black (100% vs 53%; P < .001), and have septic arthritis (35% vs 1%; P < .001). Persons with HIV who had invasive NTHi infection from 2017-2018 (n = 31) were more likely than persons with HIV who had invasive NTHi infection from 2008-2016 (n = 24) to have septic arthritis (35% vs 4%, respectively; P = .01). Pulsed-field gel electrophoresis of 174 of 179 NTHi isolates from 18- to 55-year-olds identified 2 genetically distinct clonal groups: cluster 1 (C1; n = 24) and cluster 2 (C2; n = 23). Whole-genome sequencing confirmed 2 clonal lineages of NTHi infection and revealed all C1 isolates (but none of the C2 isolates) carried IS1016 (an insertion sequence associated with H influenzae capsule genes). Persons with HIV were significantly more likely to have C1 or C2 invasive NTHi infection from 2017-2018 (28/31 [90%]) compared with from 2008-2016 among persons with HIV (10/24 [42%]; P < .001) and compared with from 2008-2018 among those without HIV (9/119 [8%]; P < .001). Among persons with C1 or C2 invasive NTHi infection who had HIV (n = 38) (median age, 34.5 years; 100% male; 100% black; 82% men who have sex with men), 32 (84%) lived in 2 urban counties and an area of significant spatial aggregation was identified compared with those without C1 or C2 invasive NTHi infection.

CONCLUSIONS AND RELEVANCE

Among persons with HIV in Atlanta, the incidence of invasive nontypeable H influenzae infection increased significantly from 2017-2018 compared with 2008-2016. Two unique but genetically related clonal strains were identified and were associated with septic arthritis among black men who have sex with men and who lived in geographic proximity.

506. Urinary Catheters Are Associated with Progression from Bacteriuria to Invasive Infections in Patients with Carbapenem-Resistant Enterobacteriaceae, Metropolitan Atlanta, 2011–2017

Background

Patients with carbapenem-resistant Enterobacteriaceae (CRE) bacteriuria have better outcomes than patients with an invasive CRE infection, but patients with bacteriuria may subsequently develop an invasive infection (“progression”). We sought to evaluate risk factors, particularly urinary catheters, for progression from CRE bacteriuria to an invasive CRE infection within one year.

Methods

We used population-based active surveillance data from the Georgia Emerging Infections Program to identify patients in metropolitan Atlanta with CRE in urine, but not in a concomitant or previous sterile site between August 1, 2011 and July 31, 2017. CRE was defined as an isolate resistant to tested third-generation cephalosporins and a minimum inhibitory concentration of ≥4 µg/mL for meropenem, doripenem or imipenem. We then assessed if these patients developed an invasive CRE infection (positive sterile site culture) with the same organism between one day and one year later. Demographics, culture site, comorbidities, and risk factors were obtained by chart review. Univariable analyses and multivariable logistic regression with progression as the outcome were performed in SAS 9.4.

Results

We identified 551 patients with CRE bacteriuria in 6 years, with an annual incidence of 1.1 cases/100,000 population. Many patients previously resided in long-term care facilities (48%), had a Charlson comorbidity index (CCI) >3 (38%), a central venous catheter (CVC, 34%) or a decubitus ulcer (27%, Table 1). Twenty-five patients (5%) progressed from CRE bacteriuria to an invasive CRE infection within one year (median 34 days). Predictors of progression in univariable analyses included the presence of a urinary catheter (OR 6.4 [95% CI: 1.9–21.6]), decubitus ulcer, CVC or other indwelling device, Klebsiella pneumoniae, black race, CCI >3, and ICU stay after urine culture was obtained (Table 2). In a multivariable analysis, urinary catheter (OR 4.6 [95% CI: 1.3–16.1]) predicted progression as well as K. pneumoniae, CCI >3 and CVC.

Conclusion

Progression from CRE bacteriuria to an invasive CRE infection is rare but clinically significant and is associated with urinary catheters. Future interventions should target urinary catheter removal, where possible, in patients with CRE bacteriuria.

Disclosures

All authors: No reported disclosures.

1714. Testing a Novel Clinical Surveillance Case Definition for Invasive Mold Infections

Background

Invasive mold infections (IMI) such as aspergillosis and mucormycosis are often fatal among immunosuppressed patients and have caused high-profile outbreaks. Surveillance for IMI is challenging because distinguishing a case from colonization or contamination is complex. The established case definition, Mycoses Study Group (MSG) criteria, lacks sensitivity. Because the need for surveillance remains, we designed a pilot IMI surveillance system within the Georgia Emerging Infections Program. Here, we describe cases identified through this system, using both the MSG criteria and a novel, more sensitive clinical case definition.

Methods

To identify potential IMI cases, we captured fungal cultures positive for mold, histopathology specimens with evidence of fungal tissue invasion, and positive galactomannan results within a 60-day window at three large hospitals in Atlanta during March 2017–2018. We excluded dimorphic fungi and hair and nail specimens. Of 194 potential cases, we selected 24 for complete medical chart review. Two physicians classified cases as proven, probable, or non-case according to MSG criteria. Cases that partially met MSG probable criteria and included antifungal treatment were classified as clinical cases; definitions were mutually exclusive (Figure 1).

Results

Of 24 potential IMI cases, 16 (66%) met an IMI case definition, including 5 proven, 2 probable and 9 clinical cases. Inter-rater agreement was 92%., Most (5/7) MSG cases involved Aspergillus and were more likely to have cancer, a transplant, or other immunosuppression compared with clinical cases (Figure 2 and 3). Clinical cases included conditions not specified in MSG criteria, including burns (1), wounds (1) or eye (4) infections. MSG and clinical cases more often had antifungal treatment (16/16 vs. 1/8) or died (4/16 vs. 0/8) compared with non-cases.

Conclusion

In this preliminary analysis of potential IMI cases, most represented true invasive infections, indicating effective exclusion of most colonization. Most of the 16 cases were classified as clinical, however, and would have been missed in a system relying on the MSG criteria alone. Results suggest that a less-specific clinical case definition incorporating antifungal treatment may improve the sensitivity and utility of IMI surveillance.

Disclosures

All authors: No reported disclosures.

2741. Seasonal Influenza Vaccine Timing in Children and Adults Hospitalized with Influenza in the United States, FluSurv-NET, 2013–2017

Background

Seasonal influenza vaccine may attenuate disease severity among people infected with influenza despite vaccination, but vaccine effectiveness may decrease with increasing time between vaccination and infection. Patient characteristics may play a role in the timing of vaccine receipt.

Methods

We used data from the Influenza Hospitalization Surveillance Network (FluSurv-NET) and included patients ≥ 9 years hospitalized with laboratory-confirmed influenza during October 1–April 30 of influenza seasons 2013–2014 through 2016–2017 who received seasonal influenza vaccine ≥ 14 days prior to admission. Vaccine history was obtained from vaccine registries, medical charts, and patient interviews. We defined “early vaccination” as vaccine receipt before October 15 and “late vaccination” as receipt after (date selected using typical season onset and median vaccination dates). Early and late groups were compared using Chi-square or Fisher exact tests.

Results

Among 21,751 vaccinated patients, 61% received vaccine before October 15, and distribution of vaccination date was similar across seasons (figure). Vaccination occurred earlier with increasing age (45% were vaccinated early among those 9–17 years but 65% in those ≥ 80 years, P < 0.01). White non-Hispanic patients were more likely to receive vaccine early compared with black non-Hispanic and Hispanic patients (63% vs. 55% and 54%; P < 0.01). Those with metabolic disorders, cardiovascular disease, kidney disease, and cancer were vaccinated earlier whereas those with HIV and liver disease were vaccinated later. Vaccine timing also varied by state (P < 0.01) but not by sex.

Conclusion

Among influenza-vaccinated older children and adults hospitalized with influenza, older age, white race, and certain medical conditions were associated with early receipt of influenza vaccination in unadjusted analysis. This may be due to frequent healthcare encounters and targeted public health strategies in high-risk groups. Understanding how timing of vaccine receipt varies among populations can provide insights into variables that must be controlled for in studying possible vaccine effectiveness waning and attenuation of disease among those who are infected despite vaccination.

Disclosures

All authors: No reported disclosures.

Antibiotic combinations that exploit heteroresistance to multiple drugs effectively control infection

Antibiotic-resistant bacteria are a significant threat to human health, with one estimate suggesting they will cause 10 million worldwide deaths per year by 2050, surpassing deaths due to cancer1. Because new antibiotic development can take a decade or longer, it is imperative to effectively use currently available drugs. Antibiotic combination therapy offers promise for treating highly resistant bacterial infections, but the factors governing the sporadic efficacy of such regimens have remained unclear. Dogma suggests that antibiotics ineffective as monotherapy can be effective in combination2. Here, using carbapenem-resistant Enterobacteriaceae (CRE) clinical isolates, we reveal the underlying basis for the majority of effective combinations to be heteroresistance. Heteroresistance is a poorly understood mechanism of resistance reported for different classes of antibiotics3-6 in which only a subset of cells are phenotypically resistant7. Within an isolate, the subpopulations resistant to different antibiotics were distinct, and over 88% of CRE isolates exhibited heteroresistance to multiple antibiotics ('multiple heteroresistance'). Combinations targeting multiple heteroresistance were efficacious, whereas those targeting homogenous resistance were ineffective. Two pan-resistant Klebsiella isolates were eradicated by combinations targeting multiple heteroresistance, highlighting a rational strategy to identify effective combinations that employs existing antibiotics and could be clinically implemented immediately.

Population-Based Active Surveillance for Culture-Confirmed Candidemia - Four Sites, United States, 2012-2016

PROBLEM/CONDITION

Candidemia is a bloodstream infection (BSI) caused by yeasts in the genus Candida. Candidemia is one of the most common health care-associated BSIs in the United States, with all-cause in-hospital mortality of up to 30%.

PERIOD COVERED

2012-2016.

DESCRIPTION OF SYSTEM

CDC's Emerging Infections Program (EIP), a collaboration among CDC, state health departments, and academic partners that was established in 1995, was used to conduct active, population-based laboratory surveillance for candidemia in 22 counties in four states (Georgia, Maryland, Oregon, and Tennessee) with a combined population of approximately 8 million persons. Laboratories serving the catchment areas were recruited to report candidemia cases to the local EIP program staff. A case was defined as a blood culture that was positive for a Candida species collected from a surveillance area resident during 2012-2016. Isolates were sent to CDC for species confirmation and antifungal susceptibility testing. Any subsequent blood cultures with Candida within 30 days of the initial positive culture in the same patient were considered part of the same case. Trained surveillance officers collected clinical information from the medical chart for all cases, and isolates were sent to CDC for species confirmation and antifungal susceptibility testing.

RESULTS

Across all sites and surveillance years (2012-2016), 3,492 cases of candidemia were identified. The crude candidemia incidence averaged across sites and years during 2012-2016 was 8.7 per 100,000 population; important differences in incidence were found by site, age group, sex, and race. The crude annual incidence was the highest in Maryland (14.1 per 100,000 population) and lowest in Oregon (4.0 per 100,000 population). The crude annual incidence of candidemia was highest among adults aged ≥65 years (25.5 per 100,000 population) followed by infants aged <1 year (15.8). The crude annual incidence was higher among males (9.4) than among females (8.0) and was approximately 2 times greater among blacks than among nonblacks (13.7 versus 5.8). Ninety-six percent of cases occurred in patients who were hospitalized at the time of or during the week after having a positive culture. One third of cases occurred in patients who had undergone a surgical procedure in the 90 days before the candidemia diagnosis, 77% occurred in patients who had received systemic antibiotics in the 14 days before the diagnosis, and 73% occurred in patients who had had a central venous catheter (CVC) in place within 2 days before the diagnosis. Ten percent were in patients who had used injection drugs in the past 12 months. The median time from admission to candidemia diagnosis was 5 days (interquartile range [IQR]: 0-16 days). Among 2,662 cases that were treated in adults aged >18 years, 34% were treated with fluconazole alone, 30% with echinocandins alone, and 34% with both. The all-cause, in-hospital case-fatality ratio was 25% for any time after admission; the all-cause in-hospital case-fatality ratio was 8% for <48 hours after a positive culture for Candida species. Candida albicans accounted for 39% of cases, followed by Candida glabrata (28%) and Candida parapsilosis (15%). Overall, 7% of isolates were resistant to fluconazole and 1.6% were resistant to echinocandins, with no clear trends in resistance over the 5-year surveillance period.

INTERPRETATION

Approximately nine out of 100,000 persons developed culture-positive candidemia annually in four U.S. sites. The youngest and oldest persons, men, and blacks had the highest incidences of candidemia. Patients with candidemia identified in the surveillance program had many of the typical risk factors for candidemia, including recent surgery, exposure to broad-spectrum antibiotics, and presence of a CVC. However, an unexpectedly high proportion of candidemia cases (10%) occurred in patients with a history of injection drug use (IDU), suggesting that IDU has become a common risk factor for candidemia. Deaths associated with candidemia remain high, with one in four cases resulting in death during hospitalization.

PUBLIC HEALTH ACTION

Active surveillance for candidemia yielded important information about the disease incidence and death rate and persons at greatest risk. The surveillance was expanded to nine sites in 2017, which will improve understanding of the geographic variability in candidemia incidence and associated clinical and demographic features. This surveillance will help monitor incidence trends, track emergence of resistance and species distribution, monitor changes in underlying conditions and predisposing factors, assess trends in antifungal treatment and outcomes, and be helpful for those developing prevention efforts. IDU has emerged as an important risk factor for candidemia, and interventions to prevent invasive fungal infections in this population are needed. Surveillance data documenting that approximately two thirds of candidemia cases were caused by species other than C. albicans, which are generally associated with greater antifungal resistance than C. albicans, and the presence of substantial fluconazole resistance supports 2016 clinical guidelines recommending a switch from fluconazole to echinocandins as the initial treatment for candidemia in most patients.

Invasive Meningococcal Disease due to Nongroupable Neisseria meningitidis-Active Bacterial Core Surveillance Sites, 2011-2016

We characterized 22 meningococcal disease cases due to nongroupable Neisseria meningitidis, a rare cause of invasive disease. Disease presentation and severity were similar to those for serogroupable meningococcal disease. However, 7 (32%) patients had complement deficiency or abnormal complement testing results, highlighting the importance of complement testing for nongroupable cases.

Epidemiology of Invasive Group B Streptococcal Infections Among Nonpregnant Adults in the United States, 2008-2016

IMPORTANCE

Group B Streptococcus (GBS) is an important cause of invasive bacterial disease. Previous studies have shown a substantial and increasing burden of GBS infections among nonpregnant adults, particularly older adults and those with underlying medical conditions.

OBJECTIVE

To update trends of invasive GBS disease among US adults using population-based surveillance data.

DESIGN, SETTING, AND PARTICIPANTS

In this population-based surveillance study, a case was defined as isolation of GBS from a sterile site between January 1, 2008, and December 31, 2016. Demographic and clinical data were abstracted from medical records. Rates were calculated using US Census data. Antimicrobial susceptibility testing and serotyping were performed on a subset of isolates. Case patients were residents of 1 of 10 catchment areas of the Active Bacterial Core surveillance (ABCs) network, representing approximately 11.5% of the US adult population. Patients were included in the study if they were nonpregnant, were 18 years or older, were residents of an ABCs catchment site, and had a positive GBS culture from a normally sterile body site.

MAIN OUTCOMES AND MEASURES

Trends in GBS cases overall and by demographic characteristics (sex, age, and race), underlying clinical conditions of patients, and isolate characteristics are described.

RESULTS

The ABCs network detected 21 250 patients with invasive GBS among nonpregnant adults from 2008 through 2016. The GBS incidence in this population increased from 8.1 cases per 100 000 population in 2008 to 10.9 in 2016 (P = .002 for trend). There were 3146 cases reported in 2016 (59% male; median age, 64 years; age range, 18-103 years). The GBS incidence was higher among men than women and among blacks than whites and increased with age. Projected to the US population, an estimated 27 729 cases of invasive disease and 1541 deaths occurred in the United States in 2016. Ninety-five percent of cases in 2016 occurred in someone with at least 1 underlying condition, most commonly obesity (53.9%) and diabetes (53.4%). Resistance to clindamycin increased from 37.0% of isolates in 2011 to 43.2% in 2016 (P = .02). Serotypes Ia, Ib, II, III, and V accounted for 86.4% of isolates in 2016; serotype IV increased from 4.7% in 2008 to 11.3% in 2016 (P < .001 for trend).

CONCLUSIONS AND RELEVANCE

The public health burden of invasive GBS disease among nonpregnant adults is substantial and continues to increase. Chronic diseases, such as obesity and diabetes, may contribute.

Epidemiology of Invasive Early-Onset and Late-Onset Group B Streptococcal Disease in the United States, 2006 to 2015: Multistate Laboratory and Population-Based Surveillance

IMPORTANCE

Invasive disease owing to group B Streptococcus (GBS) remains an important cause of illness and death among infants younger than 90 days in the United States, despite declines in early-onset disease (EOD; with onset at 0-6 days of life) that are attributed to intrapartum antibiotic prophylaxis (IAP). Maternal vaccines to prevent infant GBS disease are currently under development.

OBJECTIVE

To describe incidence rates, case characteristics, antimicrobial resistance, and serotype distribution of EOD and late-onset disease (LOD; with onset at 7-89 days of life) in the United States from 2006 to 2015 to inform IAP guidelines and vaccine development.

DESIGN, SETTING, AND PARTICIPANTS

This study used active population-based and laboratory-based surveillance for invasive GBS disease conducted through Active Bacterial Core surveillance in selected counties of 10 states across the United States. Residents of Active Bacterial Core surveillance areas who were younger than 90 days and had invasive GBS disease in 2006 to 2015 were included. Data were analyzed from December 2017 to April 2018.

EXPOSURES

Group B Streptococcus isolated from a normally sterile site.

MAIN OUTCOMES AND MEASURES

Early-onset disease and LOD incidence rates and associated GBS serotypes and antimicrobial resistance.

RESULTS

The Active Bacterial Core surveillance program identified 1277 cases of EOD and 1387 cases of LOD. From 2006 to 2015, EOD incidence declined significantly from 0.37 to 0.23 per 1000 live births (P < .001), and LOD rates remained stable (mean, 0.31 per 1000 live births). Among the mothers of 1277 infants with EOD, 617 (48.3%) had no indications for IAP and did not receive it, and 278 (21.8%) failed to receive IAP despite having indications. Serotype data were available for 1743 of 1897 patients (91.3%) from 7 sites that collect GBS isolates. Among patients with EOD, serotypes Ia (242 [27.3%]) and III (242 [27.3%]) were most common. Among patients with LOD, serotype III was most common (481 [56.2%]), and this increased from 2006 to 2015 from 0.12 to 0.20 cases per 1000 live births (P < .001). Serotype IV caused 53 cases (6.2%) of EOD and LOD combined. The 6 most common serotypes (Ia, Ib, II, III, IV, and V) caused 881 EOD cases (99.3%) and 853 LOD cases (99.7%). No β-lactam resistance was identified; 359 isolates (20.8%) tested showed constitutive clindamycin resistance. In 2015, an estimated 840 EOD cases and 1265 LOD cases occurred nationally.

CONCLUSIONS AND RELEVANCE

The rates of LOD among US infants are now higher than EOD rates. Combined with addressing IAP implementation gaps, an effective vaccine covering the most common serotypes might further reduce EOD rates and help prevent LOD, for which there is no current public health intervention.

Streptococcus pneumoniae colonization after introduction of 13-valent pneumococcal conjugate vaccine for US adults 65 years of age and older, 2015-2016

BACKGROUND

Vaccination of children with 13-valent pneumococcal conjugate vaccine (PCV13) led to declines in vaccine-type pneumococcal nasopharyngeal carriage among adults through indirect effects. In August 2014, PCV13 immunization of all U.S. adults ≥65 years of age was recommended. This study sought to define prevalence and serotype distribution of pneumococcal carriage among adults ≥65 years of age and to describe risk factors for colonization soon after introduction of PCV13 in adults.

METHODS

A cross-sectional survey of non-institutionalized U.S. adults ≥65 years of age was conducted in four states in 2015-2016. Demographic information, risk factors for disease, PCV13 vaccination history, and nasopharyngeal (NP) and oropharyngeal (OP) swabs were collected. NP and OP swabs were processed separately and pneumococcal isolates were serotyped by Quellung reaction. Antimicrobial susceptibility of pneumococcal isolates was performed. NP swabs also underwent real-time PCR for pneumococcal detection and serotyping.

RESULTS

Of 2989 participants, 45.3% (1354/2989) had been vaccinated with PCV13. Fifty-five (1.8%) carried pneumococcus (45 identified by culture and 10 by real-time PCR only) and PCV13 serotypes were found in eight (0.3%) participants. Almost half (22/45) of pneumococcal isolates were not susceptible to at least one of the antibiotics tested. Vaccine-type carriage among vaccinated and unvaccinated individuals was similar (0.2% vs. 0.1%, respectively). Respiratory symptoms were associated with higher odds of pneumococcal colonization (adjusted OR: 2.1; 95% CI = 1.1-3.8).

CONCLUSIONS

Pneumococcal carriage among non-institutionalized adults ≥65 years of age was very low. Less than 0.5% of both vaccinated and unvaccinated individuals in our study carried vaccine-type serotypes. Over a decade of PCV vaccination of children likely led to indirect effects in adults. However, given the low vaccine-type carriage rates we observed in an already high PCV13 adult coverage setting, it is difficult to attribute our findings to the direct versus indirect effects of PCV13 on adult carriage.