Deconstructing the infection control bundles for the containment of carbapenem-resistant Enterobacteriaceae

Characterization and genome analysis of novel Klebsiella pneumoniae phage vbKpUKJ_2 isolated from hospital sewage water

INTRODUCTION

Multidrug-resistant (MDR) Klebsiella pneumoniae is a critical healthcare challenge due to its extensive resistance to antibiotics and role in causing severe infections. Bacteriophages offer a promising alternative for targeting MDR pathogens. This study characterizes a novel phage, vbKpUKJ_2, isolated from hospital sewage water, against clinical K. pneumoniae isolates.

METHODS

Phage vbKpUKJ_2 was isolated and purified using the double agar overlay method. Host range and sensitivity were tested against 40 clinical K. pneumoniae isolates using growth inhibition assays. Morphological characterization was performed using transmission electron microscopy (TEM). Genomic analysis was conducted to evaluate the absence of antibiotic resistance genes and determine phylogenetic relationships. Stability assays assessed the phage's thermal and pH tolerance.

RESULTS

Phage vbKpUKJ_2 demonstrated broad range activity against clinical K. pneumoniae isolates. TEM revealed it belongs to the Drexlerviridae family. Genomic analysis confirmed the absence of antibiotic resistance genes and identified conserved functional regions shared with related phages. vbKpUKJ_2 exhibited broad pH stability (pH 4-10) and thermal stability between 30 °C and 60 °C. The one-step growth curve indicated rapid lytic activity, with a burst size of 323 phage particles per cell.

CONCLUSION

vbKpUKJ_2 shows promising therapeutic potential against MDR K. pneumoniae. Its stability, absence of resistance genes, and rapid lytic cycle highlight its suitability for inclusion in phage therapy protocols, particularly as part of combination therapies targeting MDR infections.

Facility- and patient-level factors associated with implementation of contact precautions in hospitalized VA patients with positive CRE cultures

Decreasing the time to contact precautions (CP) is critical to carbapenem-resistant Enterobacterales (CRE) prevention. Identifying factors associated with delayed CP can decrease the spread from patients with CRE. In this study, a shorter length of stay was associated with being placed in CP within 3 days.

Bloodstream Infections in Patients with Rectal Colonization by Carbapenem-Resistant Enterobacteriaceae: A Prospective Cohort Study

Purpose

Carbapenem-resistant Enterobacteriaceae (CRE) infection has become a concerning threat, especially in hospital settings; however, its phenotypic characterization, association with rectal colonization and subsequent bloodstream infections (BSI) remain to be clarified. This study aimed to investigate the incidence and risk factors of CRE infection in rectal CRE carriers and to understand the clonality of carbapenem-resistant Klebsiella pneumoniae (CRKP) strains and their association with subsequent BSI in these patients.

Patients and Methods

This was a prospectively designed cohort study. Hospitalized patients treated at our institution from April 2019 to October 2020 with intestinal CRE carriage were screened at admission and weekly thereafter until death or discharge from the hospital. Stool and blood samples were obtained for strain growth and mass spectrometry. The colonization and clinical infection isolates were analyzed by antimicrobial susceptibility testing to identify CRE. The clonality of the CRE strains and their corresponding clinical infection strains was studied by whole-genome sequencing to explore the mechanism of drug resistance and evaluate possible transmission. CRE-associated risk factors were analyzed in combination with epidemiological data.

Results

Of the 1203 patients, 85 were colonized by CRE and 21 developed CRE infection, of whom 13 developed CRE bloodstream infection (BSI). Ninety-one CRE strains were isolated from the rectal specimens of the 85 patients. Tracheotomy and chemotherapy in the past three months were independent risk factors for CRE infection in intestinal CRE carriers. ST11-KL64 (92.3%, 24/26) was the most dominant capsule and multilocus sequence typing (MLST) type among clonal CRKP isolates. Single-nucleotide polymorphism clustering showed homology of representative colonization and infection CRKP strain pairs (n=13) in the same patient. One group of leading clones was endemic in surgical intensive care units (ICUs). Twenty-four CRKP strains carried β-lactamase K. pneumonia carbapenemase 2, and 73.1% (19 strains) of CRKP carried mucoid phenotype regulator genes A2 and iucABCD.

Conclusion

In summary, intestinal CRE colonization was detectable at an elevated rate among hospitalized patients and prevalent in ICU patients, with potential rapid horizontal transmission, providing evidence that CRE BSI infection in hospitalized patients might be due to their colonized strains and indicates the correlation between intestinal colonization and BSI.

Clonal spread of carbapenemase-producing Enterobacteriaceae in a region, China

Background

The increasing number of carbapenemase-producing Enterobacterales (CPE) has become a serious problem globally. This study aimed to elucidate their geographically epidemiological characteristics.

Methods

Resistance genes were identified by polymerase chain reaction (PCR) and sequencing. Bacterial genotyping was studied using multilocus sequence typing (MLST) and wzi typing. The transferability of carbapenemase genes was determined by a broth mating method. The relationships between the rates of antimicrobial consumption and the prevalence of CRE were performed by Pearson's or Spearman's correlation analyses.

Results

A total of 930 phenotypically confirmed carbapenem-resistant Enterobacterales (CRE) isolates collected from 19 hospitals were genotypically characterized. K. pneumoniae (KP) and E. coli isolates were 785 (85.14%) and 96 (10.41%) among 922 CPE isolates. Two major carbapenemase genes blaKPC-2 and blaNDM in CPE isolates accounted for 84.6% (n = 780) and 13.77% (n = 127). ST11 comprised 86.83% (633/729) of KPC-2 KP isolates. Different combinations of extended spectrum-β-lactamase (ESBL) genes of blaSHV, blaCTX, and blaTEM were found in KPC-2 producing KP isolates, and blaCTM-M-14/15, blaSHV-11/12 and blaTEM-1 were common ESBL genotypes. The wzi typing method could further subdivide ST11 KP group into at least five subgroups, among which wzi209 (69.83%, 442/633) was the most frequently isolated, followed by wzi141 (25.28%, 160/633). Conjugation assays showed that high conjugation rates were observed in CPE (15.24%, 32/210) for NDM plasmids, but relatively low (8.1%, 17/210) for KPC-2 plasmids. Different STs, different wzis and temperature could influence plasmid conjugation efficiency. No associations between the rates of antibiotics consumption and CPE prevalence were observed. The number of intra-hospital and inter-hospital transfers of CPE patients increased gradually from 18 (17.82%, 101) and 12 (11.88%, 101) in 2015 to 63 (30.73%, 205) and 51 (24.88%, 205) in 2018 (p = 0.016 and p = 0.008), respectively. Evidence-based measures could effectively reduce the prevalence of ST11-wzi209 clone but failed to control the dissemination of ST11-wzi141 KP clone.

Conclusions

Clonal spread of CPE, especially KPC-2 ST11 KP was the key factor contributing to the CPE increase in the region. Continued vigilance for the importations should be maintained. Coordinated regional interventions are urgently needed to reduce CPE threat.

Association between Timing of Colonization and Risk of Developing Klebsiella pneumoniae Carbapenemase-Producing K. pneumoniae Infection in Hospitalized Patients

Colonization by KPC-producing Klebsiella pneumoniae (KPC-Kp) is associated with the risk of developing KPC-Kp infection. The impact of the time elapsed since a patient becomes colonized on this risk is not well known. An observational, prospective, longitudinal cohort study of colonized patients undergoing active rectal culture screening to rule out KPC-Kp colonization (July 2012 to November 2017). Patients with a positive culture at inclusion (colonized at start of follow-up) and those with a negative culture at inclusion who became colonized within 90 days (colonized during follow-up) were included in the analysis. CART analysis was used to dichotomize variables according to their association with infection. Kaplan–Meier infection-free survival curves and the log-rank test were used for group comparisons. Logistic regression was used to identify variables associated with KPC-Kp infection. Among 1310 patients included, 166 were colonized at the end of follow-up. Forty-seven out of 118 patients colonized at start of follow-up developed infection (39.8%) versus 31 out of 48 patients colonized during follow-up (64.6%; P = 0.006). Variables associated with KPC-Kp infection in the logistic regression analysis were: colonization detection during follow-up (OR, 2.74; 95% CI, 1.07 to 7.04; P = 0.03), Giannella risk score (OR, 1.51; 95% CI, 1.32 to 1.73; P < 0.001), high-risk ward (OR, 4.77; 95% CI, 1.61 to 14.10; P = 0.005) and urological manipulation after admission (OR, 3.69; 95% CI, 1.08 to 12.60; P = 0.04). In 25 out of 31 patients (80.6%) colonized during follow-up who developed KPC-Kp infection, infection appeared within 15 days after colonization. The risk of KPC-Kp infection was higher when colonization is recently acquired during hospitalization. In this prospective study, we concluded that the timing of colonization was a factor to assess when considering empirical treatment for suspected KPC-Kp infection and prophylaxis or infection control.

IMPORTANCE In this study, it was confirmed that patients who became colonized during hospitalization had a higher risk of developing KPC-Kp infection than hospitalized patients who were already colonized at the start of follow-up. Besides, the risk of infection in the group of patients who became colonized during follow-up was greater in the first weeks immediately after colonization was confirmed. Our findings support the need for designing preventive strategies for patients at the highest risk of infection development, including those admitted in high-risk hospital wards and those undergoing urological procedures.

Association between rectal colonization by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae and mortality: a prospective, observational study

BACKGROUND

We evaluated the association of Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) rectal colonization with crude mortality and whether this association is independent of the risk of KPC-Kp infection..

METHODS

Prospective cohort study of patients followed up 90 days after a study of rectal colonization. Cox-regression was used to study the variables associated with crude mortality. Sensitivity analyses for crude 90-day mortality in different subcohorts were performed.

RESULTS

A total of 1244 patients (1078 non-colonized and 166 colonized) were included. None of the non-colonized patients and 78 (47.0%) of the colonized patients developed KPC-Kp infection. Crude 90-day mortality was 18% (194/1078) in non-colonized patients and 41.6% (69/166) in colonized patients. Rectal colonization was not associated with crude mortality (Hazard Ratio [HR] 1.03; 95% CI 0.69-1.54; p = 0.85) when the model was adjusted for severe KPC-Kp infection (INCREMENT-CPE score [ICS] > 7). KPC-Kp infection with ICS > 7 was associated with an increased risk of all-cause mortality (HR 2.21; 95% CI 1.35-3.63; p = 0.002). In the sensitivity analyses, KPC-Kp colonization was not associated with mortality in any of the analyzed subcohorts, including patients who did not develop KPC-Kp infection (HR 0.93; 95%CI: 0.60-1.43; p=0.74).

CONCLUSIONS

KPC-Kp rectal colonization was not associated with crude mortality. Mortality increased when colonized patients developed severe KPC-Kp infection (ICS > 7). Rectal colonization was a necessary although insufficient condition to die from a KPC-Kp infection.

Outbreaks in Health Care Settings

Outbreaks and pseudo-outbreaks in health care settings are complex and should be evaluated systematically using epidemiologic and molecular tools. Outbreaks result from failures of infection prevention practices, inadequate staffing, and undertrained or overcommitted health care personnel. Contaminated hands, equipment, supplies, water, ventilation systems, and environment may also contribute. Neonatal intensive care, endoscopy, oncology, and transplant units are areas at particular risk. Procedures, such as bronchoscopy and endoscopy, are sources of infection when cleaning and disinfection processes are inadequate. New types of equipment can be introduced and lead to contamination or equipment and medications can be contaminated at the manufacturing source.

Validation and Extrapolation of a Multimodal Infection Prevention and Control Intervention on Carbapenem-Resistant Klebsiella pneumoniae in an Epidemic Region: A Historical Control Quasi-Experimental Study

Objective: To verify the effects of comprehensive infection prevention and control (IPC) interventions for the prevention of the cross-transmission of carbapenem-resistant Klebsiella pneumoniae (CRKP) within intensive care units (ICUs) in an epidemic region.

Methods: A historical control, quasi-experimental design was performed. The study was conducted between January 2017 and December 2019, following the implementation of a multimodal IPC bundle. The baseline period was established from January 2013 to June 2013, when only basic IPC measures were applied.

Results: A total of 748 patients were enrolled during the entire study. The incidence of ICU-acquired CRKP colonization/infection was 1.16 per 1,000 patient-days during the intervention period, compared with 10.19 per 1,000 patient-days during the baseline period (p = 0.002). The slope of the monthly incidence of CRKP at admission showed an increasing trend (p = 0.03). The incidence of ICU-acquired catheter-related bloodstream infections caused by CRKP decreased from 2.54 to 0.96 per 1,000 central-line-days (p = 0.08). Compliance with contact precautions and terminal room disinfection improved during the intervention period. All environmental surface culture samples acquired after terminal room disinfection were negative for CRKP.

Conclusion: Our findings suggest that in epidemic settings, multimodal IPC intervention strategies and consistent monitoring of compliance, may limit the spread of CRKP in ICUs.

Surveillance cultures following a regional outbreak of carbapenem-resistant Acinetobacter baumannii

OBJECTIVES

The primary aim of this study was to assess the epidemiology of carbapenem-resistant Acinetobacter baumannii (CRAB) for 9 months following a regional outbreak with this organism. We also aimed to determine the differential positivity rate from different body sites and characterize the longitudinal changes of surveillance test results among CRAB patients.

DESIGN

Observational study.

SETTING

A 607-bed tertiary-care teaching hospital in Milwaukee, Wisconsin.

PATIENTS

Any patient admitted from postacute care facilities and any patient housed in the same inpatient unit as a positive CRAB patient.

METHODS

Participants underwent CRAB surveillance cultures from tracheostomy secretions, skin, and stool from December 5, 2018, to September 6, 2019. Cultures were performed using a validated, qualitative culture method, and final bacterial identification was performed using mass spectrometry.

RESULTS

In total, 682 patients were tested for CRAB, of whom 16 (2.3%) were positive. Of the 16 CRAB-positive patients, 14 (87.5%) were residents from postacute care facilities and 11 (68.8%) were African American. Among positive patients, the positivity rates by body site were 38% (6 of 16) for tracheal aspirations, 56% (9 of 16) for skin, and 82% (13 of 16) for stool.

CONCLUSIONS

Residents from postacute care facilities were more frequently colonized by CRAB than patients admitted from home. Stool had the highest yield for identification of CRAB.

Prolonged Carriage of Carbapenemase-Producing Enterobacteriaceae: Clinical Risk Factors and the Influence of Carbapenemase and Organism Types

Prolonged carriage of carbapenemase-producing Enterobacteriaceae (CPE) constitutes a substantial epidemiologic threat. This study aimed to evaluate whether the types of carbapenemase and organism can affect the duration of carriage and to evaluate the clinical factors associated with prolonged carriage. We retrospectively reviewed data for patients admitted between May 2013 and August 2018 who were identified as CPE carriers. A total of 702 patients were identified; the major types of carbapenemase and organism were Oxacillinase (OXA)-48-like (n = 480, 68.4%) and Klebsiella pneumoniae (K. pneumoniae) (n = 584, 83.2%). The analyses of time to spontaneous decolonization using the Kaplan–Meier method showed that OXA-48-like and K. pneumoniae were significantly associated with prolonged carriage (log rank, p = 0.001 and p < 0.001). In multivariable logistic analysis to assess the risk factors for CPE prolonged carriage in the 188 patients with available follow-up culture data for 3 months, K. pneumoniae (adjusted odds ratio [aOR] 6.58; 95% confidence interval [CI], 1.05–41.27; p = 0.044), CPE positive clinical specimen (aOR 11.14; 95% CI, 4.73–26.25; p < 0.001), and concurrent Clostridioides difficile infection (CDI) (aOR 3.98, 95% CI 1.29–12.26; p = 0.016) were predictive of prolonged carriage. Our results suggest that CP-K. pneumoniae may have higher probability of prolonged carriage, while the effect of OXA-48-like CPE is inconclusive. Furthermore, patients with CP-K. pneumoniae who had positive clinical specimen or concurrent CDI can cause a vicious circle in prolonged carriage.

Three-Tiered COVID-19 Cohorting Strategy and Implications for Memory-Care

An outbreak of SARS-CoV-2 in a skilled nursing facility (SNF) can be devastating for residents and staff. Difficulty identifying asymptomatic and presymptomatic cases and lack of vaccination or treatment options make management challenging. We created, implemented, and now present a guide to rapidly deploy point-prevalence testing and 3-tiered cohorting in an SNF to mitigate an outbreak. We outline key challenges to SNF cohorting.

Containing Carbapenemase-producing Klebsiella pneumoniae in an endemic setting

Background

Carbapenemase-producing K. pneumoniae (CP-Kp) has been established as important nosocomial pathogen in most tertiary care hospitals in Greece. The aim of the present study was to examine the impact of an enhanced infection control program on the containment of CP-Kp in a haematology unit where the incidence of CP-Kp infections was high.

Methods

The study was conducted from June 2011 to December 2014 in a haematology unit of a tertiary-care 500-bed hospital located in Athens, Greece. A bundled intervention (active surveillance cultures, separation of carriers from non-carriers, assignment of dedicated nursing staff, contact precautions, environmental cleaning, and promotion of hand hygiene) was tested whether would reduce colonization and infection caused by CP-Kp.

Results

A total of 2507 rectal swabs were obtained; 1199 upon admission from June 2011 to June 2013 and 1307 during hospitalization from June 2011 to December 2012. During intervention the admission prevalence of CP-Kp colonization (p < 0.001 for linear trend), the hospitalization prevalence (p = 0.001 for linear trend) and the incidence rate of CP-Kp colonization (p = 0.072 for linear trend) were declining. Application of segmented linear regression revealed that both the change in the level of CP-Kp BSI incidence rates (p = 0.001) as well as the difference between pre- and post-intervention slopes were statistically significant (p < 0.001).

Conclusions

A bundled intervention including active surveillance cultures on admission can attain maximum containment of CP-Kp colonization and infection in endemic acute healthcare settings.

Increased Risk for Carbapenem-Resistant Enterobacteriaceae Colonization in Intensive Care Units after Hospitalization in Emergency Department

Carbapenem-resistant Enterobacteriaceae (CRE) colonization is common in hospital patients admitted to intensive care units (ICU) from the emergency department. We evaluated the effect of previous hospitalization in the emergency department on CRE colonization at ICU admission. Our case–control study included 103 cases and 201 controls; cases were patients colonized by CRE at admission to ICU and controls were patients admitted to ICU and not colonized. Risk factors were emergency department stay, use of carbapenem, Simplified Acute Physiology Score, upper digestive endoscopy, and transfer from another hospital. We found that ED stay before ICU admission was associated with CRE colonization at admission to the ICU. Our findings indicate that addressing infection control problems in EDs will help to control carbapenem resistance in ICUs.

Cohorting for preventing the nosocomial spread of Carbapenemase-Producing Enterobacterales, in non-epidemic settings: is it mandatory?

BACKGROUND

Worldwide dissemination of Carbapenemase-Producing Enterobacterales (CPE) has led to national and international guidance recommending the implementation of cohorting in healthcare settings (HS). However, in view of recent data regarding the spread of Extended-spectrum Beta-lactamase-producing Enterobacterales, we may wonder about the usefulness of this measure in a non-outbreak settings; here, individual contact isolation may be sufficient to control the risk of dissemination.

AIM/METHODS

We conducted a narrative review of the literature and discussed the role of cohorting.

FINDINGS

CPE are responsible for outbreaks in HS, which are considered the epicentre of spread of resistance strains. CPE are responsible for adverse effects such as increases in hospital stay and costs, less therapeutic options and thus higher risk of clinical failures and mortality. Environment and materials have also been described contaminated with CPE and can be the source of outbreak. Even if guidelines and publications have supported implementation of cohorting, there are no randomized studies demonstrating the mandatory nature of this measure. Most studies are descriptive and cohorting is usually one of several other measures to control outbreaks. Cohorting is not adapted to all HS, which requires human and material resources. Other measures must be strengthened such as compliance of hand hygiene, antibiotic stewardship and surveillance of contact patients. Individual risk factors of acquisition should also be evaluated.

CONCLUSION

Local epidemiology and resources must be assessed before implementing cohorting.

Patient care experience with utilization of isolation precautions: systematic literature review and meta-analysis

BACKGROUND

Use of isolation precautions (IP) may represent a trade-off between reduced transmission of infectious pathogens and reduced patient satisfaction with their care.

OBJECTIVE

To perform a systematic literature review and meta-analysis to identify if and how IPs impact patients' care experiences.

DATA SOURCES

Medline, ClinicalTrials.gov, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, PsychInfo, HSRProj and Cochrane Library databases.

STUDY ELIGIBILITY CRITERIA

Interventional and observational studies published January 1990 to May 2019 were eligible for inclusion.

PARTICIPANTS

Patients admitted to an acute-care facility.

INTERVENTIONS

IPs versus no IPs.

METHODS

Six reviewers screened titles, abstracts and full text. Experience of care reported by patients using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey was assessed as the outcome for the meta-analysis. Pooled odds ratios were calculated using the random-effects model. Heterogeneity was assessed using the I² value.

RESULTS

After screening 7073 titles and abstracts, 15 independent studies were included in the review. Pooling of unadjusted estimates from the HCAHPS survey demonstrated that IP patients were less likely to give top scores on questions pertaining to respect, communication, receiving assistance and cleanliness compared to the no-IP patients. Patients under IP with longer length of stay appeared to have more negative experiences with the care received during their stay compared to no IP.

CONCLUSIONS

Patients under IP were more likely to be dissatisfied with several aspects of patient care compared to patients not under IP. It is crucial to educate patients and healthcare workers in order to balance successful implementation of IP and patient care experiences, particularly in healthcare settings where it may be beneficial.

Epidemiology and successful containment of a carbapenem-resistant Enterobacteriaceae outbreak in a Southern Italian Transplant Institute

INTRODUCTION

Carbapenem-resistant enterobacteriaceae (CRE) infections are difficult to treat and pose a serious threat to solid organ transplant (SOT) recipients. At our institute we observed an infection burden in 2012.

METHODS

In order to contain the spread of CRE infections, we established a taskforce to implement guidelines suggested by the Centers for Disease Control and Prevention (CDC) for this type of outbreak. Here, we describe the epidemiology of the outbreak in our SOT population, and the effectiveness of such interventions, by comparing levels of CRE hospital-acquired infection (HAI) pre- and post-task force intervention (from January 2009 to December 2012, and from September 2013 to December 2016, respectively) through a linear regression model.

RESULTS

In this study, we included 933 patients who underwent a total of 1017 SOT procedures, 286 of whom had a CRE-positive culture (28.8%), of which 65 (22.7% of CRE positive) developed infection. One-year mortality post-SOT was significantly higher in patients with CRE infection. After the taskforce intervention, the CRE HAI rate in SOT showed a significant inverse trend (event rate: -1.28, CI -1.70 to 0.86; P < 0.01).

CONCLUSION

In the paucity of treatment options, the application of CDC measures in our SOT institute contributed significantly to containing CRE infections.

Use of a cohorting-unit and systematic surveillance cultures to control a Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae outbreak

OBJECTIVE

Describe the epidemiological and molecular characteristics of an outbreak of Klebsiella pneumoniae carbapenemase (KPC)-producing organisms and the novel use of a cohorting unit for its control.

DESIGN

Observational study.

SETTING

A 566-room academic teaching facility in Milwaukee, Wisconsin.

PATIENTS

Solid-organ transplant recipients.

METHODS

Infection control bundles were used throughout the time of observation. All KPC cases were intermittently housed in a cohorting unit with dedicated nurses and nursing aids. The rooms used in the cohorting unit had anterooms where clean supplies and linens were placed. Spread of KPC-producing organisms was determined using rectal surveillance cultures on admission and weekly thereafter among all consecutive patients admitted to the involved units. KPC-positive strains underwent pulsed-field gel electrophoresis and whole-genome sequencing.

RESULTS

A total of 8 KPC cases (5 identified by surveillance) were identified from April 2016 to April 2017. After the index patient, 3 patients acquired KPC-producing organisms despite implementation of an infection control bundle. This prompted the use of a cohorting unit, which immediately halted transmission, and the single remaining KPC case was transferred out of the cohorting unit. However, additional KPC cases were identified within 2 months. Once the cohorting unit was reopened, no additional KPC cases occurred. The KPC-positive species identified during this outbreak included Klebsiella pneumoniae, Enterobacter cloacae complex, and Escherichia coli. blaKPC was identified on at least 2 plasmid backbones.

CONCLUSIONS

A complex KPC outbreak involving both clonal and plasmid-mediated dissemination was controlled using weekly surveillances and a cohorting unit.

Future Challenges in Pediatric and Neonatal Sepsis: Emerging Pathogens and Antimicrobial Resistance

The incidence of severe infections caused by multidrug-resistant (MDR) pathogens is currently rising worldwide, and increasing numbers of neonates and children with serious bloodstream infections due to resistant bacteria are being reported. Severe sepsis and septic shock due to gram-negative bacteria represent a significant cause of morbidity and mortality, and contribute to high health care costs. Antimicrobial resistance among Enterobacteriaceae represents a major problem in both health care-associated and community-acquired infections, with extended-spectrum β-lactamases (ESBLs) and carbapenem-resistant Enterobacteriaceae (CRE) now presenting the main threat. These infections in adult populations have been associated with poor clinical outcomes, but very limited data have been published so far about risk factors and clinical outcome of ESBL-associated and CRE sepsis in the pediatric population. The treatment of these infections in neonates and children is particularly challenging due to the limited number of available effective antimicrobials. Evidence-based use of new and older antibiotics based on both strategic and regulatory clinical trials is paramount to improve management of these severe infections in neonates and children.

Impact of an alternating first-line antibiotics strategy in febrile neutropenia

Background

Rising antibiotic resistance poses a challenge to the management of febrile neutropenia in patients with haematological malignancies receiving chemotherapy.

Aim

We studied an alternating first-line antibiotic strategy to determine its impact on all-cause mortality and bacteremia rates in patients with febrile neutropenia.

Methods

An alternating first-line antibiotic strategy was established in mid-2013. Data for 2012 (before strategy implementation) and 2014 (post-strategy implementation) were compared. Antibiotic Heterogeneity Index (AHI) for each of the two time-periods was also calculated.

Findings

There were 2012 admissions (26082 patient-days) in 2012 and 1843 admissions (24331 patient-days) in 2014. There was no significant difference in the baseline characteristics of patients in the two groups. The defined daily doses (DDD) of cefepime (CEF) fell while the DDD of piperacillin-tazobactam (PTZ) rose in 2014 compared with 2012. Vancomycin DDD fell in 2014. The AHI was 0.466 in 2012 and 0.582 in 2014. The difference in all-cause mortality was not statistically significant. There was no difference in rates of bacteremia with CEF-resistant, PTZ-resistant and carbapenem-resistant gram-negative organisms in the two groups. Rates of new cases of Methicillin-resistant Staphylococcus aureus (MRSA) were 2.38/1000 and 2.59/1000 patient-days in 2012 and 2014 respectively. Rates of new cases of Vancomycin-resistant Enterococcus (VRE) were 1.84/1000 and 1.81/1000 patient-days in 2012 and 2014 respectively. There was no Carbapenem-resistant Enterobacteriaceae (CRE) bacteremia in 2012 and 1 in 2014.

Conclusion

An alternating first-line antibiotic strategy resulted in an increase in antibiotic heterogeneity, without increasing mortality. There was also no significant increase in bacteremia rates.

Rapid detection of resistance to carbapenems and cephalosporins in Enterobacteriaceae using liquid chromatography tandem mass spectrometry

Carbapenemase producing Enterobacteriaceae (CPE) are becoming a global healthcare concern. Current laboratory methods for the detection of CPE include screening followed by confirmatory phenotypic and genotypic tests. These processes would generally take ≥72 hours, which could negatively impact patient care and Infection Control practices. To this end, we developed a protocol for rapid resistance testing (RRT) to detect hydrolysis in a panel of beta lactam antibiotics consisting of ampicillin, cefazolin, cefotaxime and imipenem, using liquid chromatography tandem mass spectrometry. Ninety—nine beta lactamase producing Enterobacteriaceae isolates were used to evaluate the RRT method, 54 isolates were CPE and 45 isolates were Class A or AmpC beta lactamase producing Enterobacteriaceae but not carbapenemase producers. We also tested 10 E.coli isolates that were susceptible to ampicillin, cefazolin, cefotaxime and imipenem. Receiver Operating Characteristic (ROC) Curves analysis showed that imipenem had a sensitivity and a specificity of 100% for crabapenemase detection at hydrolysis cut off values that are greater than 50% and less than or equal to 80%. The RRT protocol can be conducted in a time frame of less than 2 hours. This preliminary study shows that the rapid resistance testing protocol might have utility for the rapid detection of CPE. Additional work with a greater number and variety of beta- lactamase producing Enterobacteriaceae isolates is required to validate these preliminary findings.

Clinical factors predicting persistent carriage of Klebsiella pneumoniae carbapenemase-producing carbapenem-resistant Enterobacteriaceae among patients with known carriage

BACKGROUND

Information on the natural duration of carbapenem-resistant Enterobacteriaceae (CRE) carriage and factors associated with persistence of carriage is limited.

AIM

To evaluate the clinical variables associated with persistent carriage of Klebsiella pneumoniae carbapenemase (KPC)-producing CRE.

METHODS

Data for patients admitted between June 2015 and December 2016 who were identified as KPC-producing CRE carriers by either rectal swabs or clinical cultures were reviewed retrospectively. Patients with follow-up culture data for three months after initial acquisition were included. Regression models were used to evaluate the clinical variables associated with persistence of carriage.

FINDINGS

Of the 100 eligible patients, 50 patients (50%) experienced spontaneous decolonization within three months. Among the 50 patients (50%) who remained culture positive after three months, 26 patients carried KPC-producing CRE after six months. Multi-variable analysis revealed that re-admission [adjusted odds ratio (aOR) 9.96; 95% confidence interval (CI) 1.13-87.98; P=0.039], duration of hospitalization (aOR 1.03; 95% CI 1.01-1.05; P=0.003), positive clinical culture (aOR 6.26; 95% CI 1.28-30.54; P=0.023) and carbapenem use (OR 9.15; 95% CI 1.85-45.27; P=0.007) were predictive for persistent carriage after six months.

CONCLUSION

The results suggest that patients with KPC-producing CRE in clinical specimens who are using carbapenem, particularly those with multiple and prolonged hospitalizations, are more likely to remain carriers after six months of initial acquisition. This information is useful for coordinating strategies for pre-emptive isolation by predicting the CRE carriage status appropriately, and ensuring active surveillance through risk factor stratification.

Emergence and establishment of KPC-2-producing ST11 Klebsiella pneumoniae in a general hospital in Shanghai, China

The aim of this study was to investigate the characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) collected during an outbreak in a Chinese teaching hospital and to provide insights into the prevention and control of nosocomial infection. We collected unique CRKP clinical isolates from 2009 to 2013. Antibiotic-resistant genes were identified by polymerase chain reaction (PCR) and sequencing. The isolates were typed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Plasmids were classified using a PCR-based incompatibility/replicon typing method and a replicon sequence typing method. Conjugation experiments were performed to evaluate the transferability of carbapenem-resistant genes. Whole genome sequencing (WGS) was conducted to further investigate the genetic background of the isolates. Infection control practices were reviewed throughout the study period. Klebsiella pneumoniae sequence type (ST) 11 emerged in 2010 and acquired the bla KPC-2 gene by 2011. From 2011 to 2013, ST11 KPC-2-producing CRKP (G type) prevailed as the most common CRKP in our hospital, causing a prolonged outbreak. The majority of these CRKP strains possess an IncFII plasmid, with Tn1721-bla KPC-2-ΔTn3-IS26 bearing the genetic structure for bla KPC-2. Infection prevention control measures available at the time contained the initial outbreak, but had no effect on the spread of CRKP later. This study demonstrated the seriousness concerning the spread of KPC-2-producing ST11 CRKP in a Chinese hospital, indicating that current prevention and control strategies for carbapenem-resistant Enterobacteriaceae (CRE) nosocomial infection need to be investigated and adjusted.

Stalking a lethal superbug by whole-genome sequencing and phylogenetics: Influence on unraveling a major hospital outbreak of carbapenem-resistant Klebsiella pneumoniae

BACKGROUND

From July 2010-April 2013, Leipzig University Hospital experienced the largest outbreak of a Klebsiella pneumoniae carbapenemase 2 (KPC-2)-producing Klebsiella pneumoniae (KPC-2-Kp) strain observed in Germany to date. After termination of the outbreak, we aimed to reconstruct transmission pathways by phylogenetics based on whole-genome sequencing (WGS).

METHODS

One hundred seventeen KPC-2-Kp isolates from 89 outbreak patients, 5 environmental KPC-2-Kp isolates, and 24 K pneumoniae strains not linked to the outbreak underwent WGS. Phylogenetic analysis was performed blinded to clinical data and based on the genomic reads.

RESULTS

A patient from Greece was confirmed as the source of the outbreak. Transmission pathways for 11 out of 89 patients (12.4%) were plausibly explained by descriptive epidemiology, applying strict definitions. Five of these and an additional 15 (ie, 20 out of 89 patients [22.5%]) were confirmed by phylogenetics. The rate of phylogenetically confirmed transmissions increased significantly from 8 out of 66 (12.1% for the time period before) to 12 out of 23 patients (52.2% for the time period after; P <.001) after implementation of systematic screening for KPC-2-Kp (33,623 screening investigations within 11 months). Using descriptive epidemiology, systematic screening showed no significant effect (7 out of 66 [10.6%] vs 4 out of 23 [17.4%] patients; P = .465). The phylogenetic analysis supported the assumption that a contaminated positioning pillow served as a reservoir for the persistence of KPC-2-Kp.

CONCLUSIONS

Effective phylogenetic identification of transmissions requires systematic microbiologic screening. Extensive screening and phylogenetic analysis based on WGS should be started as soon as possible in a bacterial outbreak situation.

Carbapenem-resistant Enterobacteriaceae at a low prevalence tertiary care center: Patient-level risk factors and implications for an infection prevention strategy

Limited treatment options and a growing global threat from carbapenem-resistant Enterobacteriaceae (CRE) infections illustrate the importance of understanding the epidemiology of CRE. Using a retrospective chart review and point prevalence testing demonstrated specific patient risk factors for CRE-positive clinical cultures in a tertiary medical center with a low CRE prevalence.

Infection control interventions affected by resource shortages: impact on the incidence of bacteremias caused by carbapenem-resistant pathogens

We evaluated an infection control (IC) program influenced by personnel and material resource shortages on the incidence of bloodstream infections (BSI) due to carbapenem-resistant Klebsiella pneumoniae (CRKP), Acinetobacter baumannii (CRAB), and Pseudomonas aeruginosa (CRPA) in an endemic region. Between January 2010 and December 2015, all BSI episodes caused by CRKP, CRAB, and CRPA were recorded. An IC bundle was implemented in January 2012. We evaluated the effect of the interventions on BSI rates between the pre-intervention (2010-2011) and intervention (2012-2013) periods, using an interrupted time-series model. From 2014, when interventions were still applied, BSI incidence was gradually increased. For this reason, we evaluated with a linear mixed effects model several factors possibly contributing to this increase for the years 2012-2015, which was considered as the intervention/follow-up period. During the study period, 351 patients with BSI were recorded, with a total of 538 episodes; the majority (83.6%) occurred in the intensive care unit (ICU). The BSI incidence rate per year during 2010-2015 for ICU patients was 21.03/19.63/17.32/14.45/22.85/25.02 per 1000 patient-days, respectively, with the reduction in BSI levels after the start of intervention marginal (p = 0.054). During the follow-up period (2014-2015), the most influential factors for the increased BSI incidence were the reduced participation in educational courses and compliance with hand hygiene. The implementation of IC interventions reduced the BSI incidence rates, particularly for ICU patients. However, factors possibly related to the restrictions of human and material resources apparently contributed to the observed expansion of BSI in our endemic setting.

The association between infection control interventions and carbapenem-resistant Enterobacteriaceae incidence in an endemic hospital

BACKGROUND

Israel experienced a national outbreak of carbapenem-resistant Enterobacteriaceae (CRE) starting in 2006.

AIM

To assess the association between infection control (IC) interventions implemented in a referral hospital in Israel and CRE incidence.

METHODS

Retrospective quasi-experimental study of prospectively collected data. CRE incidence, defined as the number of patients newly acquiring CRE in surveillance or clinical samples per 100,000 hospital-days, was plotted quarterly between 2005 and 2016. IC interventions were applied at different time-points throughout this period. Data were collected on IC staffing, number of rectal surveillance cultures, and carbapenem consumption. Autocorrelated segmented linear regression analysis was used to assess the time-points at which a significant change in the CRE incidence trend occurred, and the association between the timing of IC intervention implementation and observed CRE trends was assessed. Trends between time-points were expressed as quarterly percent change (QPC) with 95% confidence intervals (CIs).

FINDINGS

Between 2005 and 2008, CRE incidence increased significantly (QPC: 19.7%; CI: 11.5-28.4), reaching a peak of 186.6 new acquisitions per 100,000 hospital-days. From mid-2011 until the end of follow-up, there was a significantly decreasing incidence trend (QPC: -4.5; CI: -6.4 to -2.5). Cohorting of patients, screening of contacts and high-risk patients on admission were insufficient to control the epidemic. Improved hand hygiene compliance, cohorting with dedicated nursing staff, addition of regular screening in high-risk departments, and carbapenem restriction were required. Decreasing CRE incidence was observed with an infectious diseases/IC staffing of 1.2-1.5 per 100 beds and 20,000-36,000 yearly CRE surveillance samples.

CONCLUSION

A multi-faceted hospital-wide intervention programme is required to control CRE in hospital settings.

Evaluating the Impact of Antibiotic Exposures as Time-Dependent Variables on the Acquisition of Carbapenem-Resistant Acinetobacter baumannii

OBJECTIVES

To determine the time-dependent effect of antibiotics on the initial acquisition of carbapenem-resistant Acinetobacter baumannii.

DESIGN

Retrospective cohort study.

SETTING

Forty-bed trauma ICU in Miami, FL.

PATIENTS

All consecutive patients admitted to the unit from November 1, 2010, to November 30, 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients underwent surveillance cultures at admission to the unit and weekly thereafter. The primary outcome was the acquisition of carbapenem-resistant A. baumannii on surveillance cultures. Daily antibiotic exposures during the time of observation were used to construct time-dependent variables, including cumulative exposures (in grams and daily observed doses [defined daily doses]). Among 360 patients, 45 (12.5%) became colonized with carbapenem-resistant A. baumannii. Adjusted Cox models showed that each additional point in the Acute Physiologic and Chronic Health Evaluation score increased the hazard by 4.8% (hazard ratio, 1.048; 95% CI, 1.010-1.087; p = 0.0124) and time-dependent exposure to carbapenems quadrupled the hazard (hazard ratio, 4.087; 95% CI, 1.873-8.920; p = 0.0004) of acquiring carbapenem-resistant A. baumannii. Additionally, adjusted Cox models determined that every additional carbapenem defined daily dose increased the hazard of acquiring carbapenem-resistant A. baumannii by 5.1% (hazard ratio, 1.051; 95% CI, 1.007-1.093; p = 0.0243).

CONCLUSIONS

Carbapenem exposure quadrupled the hazards of acquiring A. baumannii even after controlling for severity of illness.

Carbapenem-Resistant Enterobacteriaceae: A Strategic Roadmap for Infection Control

The incidence of carbapenem-resistant Enterobacteriaceae (CRE) has increased worldwide with great regional variability. Infections caused by these organisms are associated with crude mortality rates of up to 70%. The spread of CRE in healthcare settings is both an important medical problem and a major global public health threat. All countries are at risk of falling victim to the emergence of CRE; therefore, a preparedness plan is required to avoid the catastrophic natural course of this epidemic. Proactive and adequate preventive measures locally, regionally, and nationally are required to contain the spread of these bacteria. The keys to success in preventing the establishment of CRE endemicity in a region are early detection through targeted laboratory protocols and containment of spread through comprehensive infection control measures. This guideline provides a strategic roadmap for infection control measures based on the best available evidence and expert opinion, to enable preparation of a multifaceted preparedness plan to abort epidemics of CRE. Infect Control Hosp Epidemiol 2017;38:580-594.

Carbapenem-resistant Klebsiella pneumoniae in high-risk haematological patients: factors favouring spread, risk factors and outcome of carbapenem-resistant Klebsiella pneumoniae bacteremias

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (CRKP) spread and infections in patients with haematological malignancies are a serious concern especially in endemic areas. Treatment failures and delay in appropriate therapy for CRKP infections are frequent and the mortality rate associated with CRKP bacteremia in neutropenic haematological patients is reported about 60%.

METHODS

Haematological patients harboring CRKP hospitalized between February 2012 and May 2013 in an Italian Teaching hospital were examined. Conditions favouring CRKP spread in a haematological unit, risk factors for bacteremia in CRKP-carriers and for CRKP bacteremia-related death were evaluated in this observational retrospective study.

RESULTS

CRKP was isolated in 22 patients, 14 (64%) had bacteremia. Control measures implementation, particularly the weekly rectal screening for CRKP performed in all hospitalized patients and contact precautions for CRKP-carriers and newly admitted patients until proved CRKP-negative, reduced significantly the CRKP spread (14 new carriers identified of 131 screened patients vs 5 of 242 after the intervention, p = 0.001). Fifty-eight percent of carriers developed CRKP bacteremia, and acute myeloid leukemia (AML) resulted independently associated with the bacteremia occurrence (p = 0.02). CRKP bacteremias developed mainly during neutropenia (86%) and in CRKP-carriers (79%). CRKP bacteremias were breakthrough in 10 cases (71%). Ten of 14 patient with CRKP bacteremias died (71%) and all had AML. The 70% of fatal bacteremias occurred in patients not yet recognized as CRKP-carriers and 80% were breakthrough. Initial adequate antibiotic therapy resulted the only independent factor able to protect against death (p = 0.02).

CONCLUSIONS

The identification of CRKP-carriers is confirmed critical to prevent CRKP spread. AML patients colonized by CRKP resulted at high risk of CRKP-bacteremia and poor outcome and the adequacy of the initial antibiotic therapy may be effective to improve survival. To limit the increase of resistance, the extensive use of antibiotics active against CRKP should be avoided, but in the setting of high CRKP pressure and high-risk CRKP-colonized haematological patients, timely empiric antibiotic combinations active against CRKP could be suggested as treatment of febrile neutropenia.

How to measure the impacts of antibiotic resistance and antibiotic development on empiric therapy: new composite indices

OBJECTIVES

We aimed to construct widely useable summary measures of the net impact of antibiotic resistance on empiric therapy. Summary measures are needed to communicate the importance of resistance, plan and evaluate interventions, and direct policy and investment.

DESIGN, SETTING AND PARTICIPANTS

As an example, we retrospectively summarised the 2011 cumulative antibiogram from a Toronto academic intensive care unit.

OUTCOME MEASURES

We developed two complementary indices to summarise the clinical impact of antibiotic resistance and drug availability on empiric therapy. The Empiric Coverage Index (ECI) measures susceptibility of common bacterial infections to available empiric antibiotics as a percentage. The Empiric Options Index (EOI) varies from 0 to 'the number of treatment options available', and measures the empiric value of the current stock of antibiotics as a depletable resource. The indices account for drug availability and the relative clinical importance of pathogens. We demonstrate meaning and use by examining the potential impact of new drugs and threatening bacterial strains.

CONCLUSIONS

In our intensive care unit coverage of device-associated infections measured by the ECI remains high (98%), but 37-44% of treatment potential measured by the EOI has been lost. Without reserved drugs, the ECI is 86-88%. New cephalosporin/β-lactamase inhibitor combinations could increase the EOI, but no single drug can compensate for losses. Increasing methicillin-resistant Staphylococcus aureus (MRSA) prevalence would have little overall impact (ECI=98%, EOI=4.8-5.2) because many Gram-positives are already resistant to β-lactams. Aminoglycoside resistance, however, could have substantial clinical impact because they are among the few drugs that provide coverage of Gram-negative infections (ECI=97%, EOI=3.8-4.5). Our proposed indices summarise the local impact of antibiotic resistance on empiric coverage (ECI) and available empiric treatment options (EOI) using readily available data. Policymakers and drug developers can use the indices to help evaluate and prioritise initiatives in the effort against antimicrobial resistance.

Control of carbapenemase-producing Enterobacteriaceae outbreaks in acute settings: an evidence review

BACKGROUND

In recent years, infections with carbapenemase-producing Enterobacteriaceae (CPE) have been increasing globally and present a major public health challenge.

AIM

To review the international literature: (i) to describe CPE outbreaks in acute hospital settings globally; and (ii) to identify the control measures used during these outbreaks and report on their effectiveness.

METHODS

A systematic search of MEDLINE and EMBASE databases, abstract lists for key conferences and reference lists of key reviews was undertaken, and information on unpublished outbreaks was sought for 2000-2015. Where relevant, risk of bias was assessed using the Newcastle-Ottawa scale. A narrative synthesis of the evidence was conducted.

FINDINGS

Ninety-eight outbreaks were eligible. These occurred worldwide, with 53 reports from Europe. The number of cases (CPE infection or colonization) involved in outbreaks varied widely, from two to 803. In the vast majority of outbreaks, multi-component infection control measures were used, commonly including: patient screening; contact precautions (e.g. gowns, gloves); handwashing interventions; staff education or monitoring; enhanced environmental cleaning/decontamination; cohorting of patients and/or staff; and patient isolation. Seven studies were identified as providing the best-available evidence on the effectiveness of control measures. These demonstrated that CPE outbreaks can be controlled successfully using a range of appropriate, commonly used, infection control measures. However, risk of bias was considered relatively high for these studies.

CONCLUSION

The findings indicate that CPE outbreaks can be controlled using combinations of existing measures. However, the quality of the evidence base is weak and further high-quality research is needed, particularly on the effectiveness of individual infection control measures.

Active surveillance of carbapenem-resistant Enterobacteriaceae in intensive care units: Is it cost-effective in a nonendemic region?

OBJECTIVE

Carbapenem-resistant Enterobacteriaceae (CRE) cause significant morbidity and mortality in intensive care unit (ICU) settings. We examined potential cost-effectiveness of active CRE surveillance at ICUs in a nonendemic region from the perspective of a Hong Kong health care provider.

METHODS

A decision analytic model was designed to simulate outcomes of active CRE surveillance in ICUs. Outcome measures included CRE-associated direct medical cost, infection rate, mortality rate, quality-adjusted life year (QALY) loss, and incremental cost per QALY saved by active surveillance. Model inputs were derived from the literature. Sensitivity analyses evaluated the influence of uncertainty of model variables.

RESULTS

In base-case analysis, the surveillance group was more costly ($1,260 vs $1,256) with lower CRE infection rate (5.670% vs 5.902%), CRE-associated mortality rate (2.139% vs 2.455%), and CRE-associated QALY loss (0.3335 vs 0.3827) than the control group. Incremental cost per QALY saved of active surveillance was $81 per QALY saved. One-way sensitivity analyses found base-case results to be robust to a variety of model inputs. In 10,000 Monte Carlo simulations, the surveillance group was the preferred option 99.98% of time.

CONCLUSIONS

Active CRE surveillance in ICUs appears to be highly cost-effective to reduce CRE infection rate, mortality rate, and QALY loss in a low CRE burden region.

Epidemiologic and Genotypic Review of Carbapenemase-Producing Organisms in British Columbia, Canada, between 2008 and 2014

Carbapenemase-producing organisms (CPOs) are a serious emerging problem for health care facilities worldwide. Owing to their resistance to most antimicrobial therapies, CPOs are difficult to treat and pose a challenge for infection prevention and control. Since 2010, lab-based surveillance for CPOs and PCR-based testing were implemented in British Columbia (BC), Canada. A review of CPOs in BC from 2008 to March 2014 was done to characterize the resistance mechanisms and possible clonal strain transmission and to compare pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and plasmid restriction fragment length polymorphism (RFLP) as molecular typing tools. During this study period, a total of 177 CPO cases were identified. Patient demographics and travel history were reviewed, and a descriptive analysis was carried out. PFGE profiles, MLST, and plasmid RFLP analysis for a subset of Escherichia coli, Klebsiella pneumoniae, and Enterobacter species isolates were obtained and analyzed. Our findings demonstrate that CPOs have been increasing in number in BC over time, from 1 isolate/year retrospectively identified in 2008 and 2009 to 82 isolates in 2013 and 30 isolates in the first quarter of 2014. Overall, K. pneumoniae isolates lack clonality, although some seemingly related clusters have been found. Plasmid analysis showed evidence of the spread of plasmids carrying carbapenemase-encoding genes between the examined isolates. Analysis of Enterobacter cloacae isolates revealed a more clonal nature of these CPOs in BC. The presence of related clusters provides evidence of interpatient organism transmission both within and between institutions. Although in our study, NDM-harboring E. cloacae isolates appeared to spread clonally, the spread of carbapenem resistance in K. pneumoniae seems to be plasmid mediated.

Carbapenem-resistant Enterobacteriaceae carriers in acute care hospitals and postacute-care facilities: The effect of organizational culture on staff attitudes, knowledge, practices, and infection acquisition rates

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) carriers are frequently transferred between acute care hospitals (ACHs) and postacute-care facilities (PACFs). Compliance of health care workers with infection prevention guidelines in both care settings may be influenced by the institution's organizational culture.

OBJECTIVES

To assess the association between organizational culture and health care workers' attitudes, knowledge, practices, and CRE acquisition rate and to identify differences between different care settings and health care workers' sectors.

METHODS

Cross-sectional descriptive design. Self-administered questionnaires were distributed to a sample of 420 health care workers from 1 ACH and 1 PACF belonging to the same health maintenance organization located in central Israel.

RESULTS

The organizational culture factor known as staff engagement was positively correlated with infection prevention attitudes and compliance with contact precaution protocols and negatively correlated with CRE acquisition rate. In the 2 care settings, health care workers' attitudes, knowledge, and practices were found to be similar, but CRE acquisition rate was lower in PACFs. Compliance with contact precaution protocols by physicians was lower than compliance reported by other health care workers. Auxiliary staff reported lower knowledge.

CONCLUSIONS

In a setting of endemic CRE where a multifaceted intervention is already being implemented, organizational culture variables can predict health care workers' attitudes, knowledge, and practices and in turn can affect CRE acquisition rates.

Four Cases of Carbapenem-Resistant Enterobacteriaceae Infection from January to March in 2014

Infection with carbapenem-resistant Enterobacteriaceae (CRE) and other multidrug resistant bacteria has increased rapidly in Korea. The Korea Centers for Disease Control and Prevention reported 1,609 cases of CRE infection in the country in 2013. The risk factors for CRE infection include history of treatment with antibiotics such as cephalosporins or carbapenem, trauma, diabetes, cancer, and history of ventilator support. Herein, we report four cases of CRE infection seen during a 3-month period in our hospital in 2014. CRE infection is associated with a high mortality rate of 30% to 50%, even with combination antibiotic therapy. Prevention of CRE infection in hospital settings is fundamental to controlling its transmission. Key preventive measures include, contact precautions, hand hygiene, education of healthcare personnel, screening for CRE when indicated, and exercising discretion in prescribing carbapenem or cephalosporins.

Carbapenemase-Producing Klebsiella pneumoniae, a Key Pathogen Set for Global Nosocomial Dominance

The management of infections due to Klebsiella pneumoniae has been complicated by the emergence of antimicrobial resistance, especially to carbapenems. Resistance to carbapenems in K. pneumoniae involves multiple mechanisms, including the production of carbapenemases (e.g., KPC, NDM, VIM, OXA-48-like), as well as alterations in outer membrane permeability mediated by the loss of porins and the upregulation of efflux systems. The latter two mechanisms are often combined with high levels of other types of β-lactamases (e.g., AmpC). K. pneumoniae sequence type 258 (ST258) emerged during the early to mid-2000s as an important human pathogen and has spread extensively throughout the world. ST258 comprises two distinct lineages, namely, clades I and II, and it seems that ST258 is a hybrid clone that was created by a large recombination event between ST11 and ST442. Incompatibility group F plasmids with blaKPC have contributed significantly to the success of ST258. The optimal treatment of infections due to carbapenemase-producing K. pneumoniae remains unknown. Some newer agents show promise for treating infections due to KPC producers; however, effective options for the treatment of NDM producers remain elusive.

Prevalence of Klebsiella pneumoniae strains producing carbapenemases and increase of resistance to colistin in an Italian teaching hospital from January 2012 To December 2014

Background

The aim of this study was to characterize the spread of carbapenemase-producing Klebsiella pneumoniae (CPKP) in a tertiary level hospital using ongoing active surveillance with rectal swab cultures. Furthermore, this study analyzed the presence of CPKP in the clinical samples (CS) of a single patient as well as the evolution of Colistin-sensitive strains (CoS) to Colistin-resistant strains (CoR).

Methods

This study was performed from January 1, 2012 to December 31, 2014. In 2012, a survey was conducted in the Intensive Care Department. In autumn 2013, active monitoring was extended to the Surgery Department, and since mid-2014, the surveillance has included the Medical Department as well. Only the first isolated strain from each patient was included. Antimicrobial susceptibility testing was performed on CPKP isolates: Klebsiella pneumoniae carbapenemase, oxacillinase-48, Verona integron-encoded metallo-β-lactamase and New Delhi metallo-β-lactamase were detected using a validated in-house PCR method, and multilocus sequence typing (MLST) was used to investigate the clonal transmission of strains.

Results

A total of 15,104 patients were included in the study, and 496 consecutive non-replicated strains of CPKP were collected: 149 strains were collected in 2012 (39 [26.2 %] from surveillance rectal swabs [SRS]), 133 strains were collected in 2013 (70 [52.6 %] from SRS) and 214 strains were collected in 2014 (164 [76.6 %] from SRS). We observed a significant increase in the percentage of positive SRS cases in 2014 relative to 2013 and 2012 (p = 0.0001 and p = 0.0172, respectively) and in the proportion of CPKP first isolated by SRS relative to those identified by CS (p < 0.0001). Among all available samples, the number of CoR isolated from SRS was higher in 2013 and 2014 compared with 2012 (p = 0.0019 and p = 0.008, respectively). ST-258 and ST-512 were more prevalent in the tested specimens, and a new single locus variant (SLV) of ST-512 (ST-745) was isolated.

Conclusions

The results of this 3-year study of 15,104 patients highlight the clinical relevance of antimicrobial resistance as well as the drug-selection pressure of colistin therapy. The active surveillance in the three different departments increased the level of CPKP cases isolated by SRS.

Effectiveness of contact precautions against multidrug-resistant organism transmission in acute care: a systematic review of the literature

Contact precautions are widely recommended to prevent multidrug-resistant organism (MDRO) transmission. However, conflicting data exist regarding their effectiveness. Prior systematic reviews examined contact precautions as part of a larger bundled approach, limiting ability to understand their effectiveness. The aim of this review was to characterize the effectiveness of contact precautions alone against transmission of any MDRO among adult acute care patients. Directed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, comprehensive searches of four electronic scientific literature databases were conducted for studies published in English from January 2004 to June 2014. Studies were included if interventional, original research, evaluating contact isolation precautions against MDRO transmission among inpatients. Searches returned 284 studies, six of which were included in the review. These studies measured four different MDROs with one study showing a reduction in transmission. Whereas studies were of high quality regarding outcome operationalization and statistical analyses, overall quality was moderate to low due to poor intervention description, population characterization and potential biases. Where compliance was measured (N = 4), it presented a threat to validity because it included select parts of the intervention, ranged from 21% to 87%, and was significantly different across study phases (N = 2). The poor quality of evidence on this topic continues to limit interpretation of these data. Hence, this conflicting body of literature does not constitute evidence for or against contact precautions. We recommend that researchers consider power calculation, compliance monitoring, non-equivalent concurrent controls when designing future studies on this topic.

Carbapenem-resistant Klebsiella pneumoniae producing New Delhi metallo-β-lactamase at an acute care hospital, Colorado, 2012

OBJECTIVE

To investigate an outbreak of New Delhi metallo-β-lactamase (NDM)-producing carbapenem-resistant Enterobacteriaceae (CRE) and determine interventions to interrupt transmission.

DESIGN, SETTING, AND PATIENTS

Epidemiologic investigation of an outbreak of NDM-producing CRE among patients at a Colorado acute care hospital.

METHODS

Case patients had NDM-producing CRE isolated from clinical or rectal surveillance cultures (SCs) collected during the period January 1, 2012, through October 20, 2012. Case patients were identified through microbiology records and 6 rounds of SCs in hospital units where they had resided. CRE isolates were tested by real-time polymerase chain reaction for blaNDM. Medical records were reviewed for epidemiologic links; relatedness of isolates was evaluated by pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Infection control (IC) was assessed through staff interviews and direct observations.

RESULTS

Two patients were initially identified with NDM-producing CRE during July-August 2012. A third case patient, admitted in May, was identified through microbiology records review. SC identified 5 additional case patients. Patients had resided in 11 different units before identification. All isolates were highly related by PFGE. WGS suggested 3 clusters of CRE. Combining WGS with epidemiology identified 4 units as likely transmission sites. NDM-producing CRE positivity in certain patients was not explained by direct epidemiologic overlap, which suggests that undetected colonized patients were involved in transmission.

CONCLUSIONS

A 4-month outbreak of NDM-producing CRE occurred at a single hospital, highlighting the risk for spread of these organisms. Combined WGS and epidemiologic data suggested transmission primarily occurred on 4 units. Timely SC, combined with targeted IC measures, were likely responsible for controlling transmission.

Genome sequencing of an extended series of NDM-producing Klebsiella pneumoniae isolates from neonatal infections in a Nepali hospital characterizes the extent of community- versus hospital-associated transmission in an endemic setting

NDM-producing Klebsiella pneumoniae strains represent major clinical and infection control challenges, particularly in resource-limited settings with high rates of antimicrobial resistance. Determining whether transmission occurs at a gene, plasmid, or bacterial strain level and within hospital and/or the community has implications for monitoring and controlling spread. Whole-genome sequencing (WGS) is the highest-resolution typing method available for transmission epidemiology. We sequenced carbapenem-resistant K. pneumoniae isolates from 26 individuals involved in several infection case clusters in a Nepali neonatal unit and 68 other clinical Gram-negative isolates from a similar time frame, using Illumina and PacBio technologies. Within-outbreak chromosomal and closed-plasmid structures were generated and used as data set-specific references. Three temporally separated case clusters were caused by a single NDM K. pneumoniae strain with a conserved set of four plasmids, one being a 304,526-bp plasmid carrying bla(NDM-1). The plasmids contained a large number of antimicrobial/heavy metal resistance and plasmid maintenance genes, which may have explained their persistence. No obvious environmental/human reservoir was found. There was no evidence of transmission of outbreak plasmids to other Gram-negative clinical isolates, although bla(NDM) variants were present in other isolates in different genetic contexts. WGS can effectively define complex antimicrobial resistance epidemiology. Wider sampling frames are required to contextualize outbreaks. Infection control may be effective in terminating outbreaks caused by particular strains, even in areas with widespread resistance, although this study could not demonstrate evidence supporting specific interventions. Larger, detailed studies are needed to characterize resistance genes, vectors, and host strains involved in disease, to enable effective intervention.