Outcomes of carbapenem-resistant Klebsiella pneumoniae infection and the impact of antimicrobial and adjunctive therapies

Description of carbapenemase-producing Enterobacteriaceae isolates in a Spanish tertiary hospital. Epidemiological analysis and clinical impact

OBJECTIVE

The aim of the study was to carry out an epidemiological analysis of patients with carbapenemase-producing Enterobacteriaceae (CPE) isolations in our hospital as well as to perform a description of the genotypic temporal evolution of CPE isolated.

METHODS

An observational prospective cohort study was performed involving all patients with CPE isolates from clinical samples during November 2014 to November 2016 in a Spanish teaching hospital. Patients were clinically evaluated and classified either as infected or colonized. Information on the consumption of carbapenems in the hospital during the study period was also analyzed. PCR was used for identification of the carbapenemase genes blaKPC, blaVIM, and blaOXA-48.

RESULTS

A total of 301 CPE isolates were obtained (107 in 2014, 89 in 2015 and 105 in 2016). Klebsiella pneumoniae (73.4%) was the most prevalent microorganism. Hundred and seventy (56.7%) of carbapenemases detected were blaOXA-48, 73 (24.3%) were blaKPC and 57 (19%) were blaVIM. In year 2014 KPC was predominant while in 2016 OXA-48 predominated. In 2014 we observed a significant association between the medical wards and the ICU with a higher prevalence of OXA-48 (OR 4.15; P<0.001) and VIM (OR 7.40; P<0.001) in the univariate analysis, in the following years there was no association. Regarding the clinical significance of microbiological results after assessing our patients, 60% of isolates represented infection and 40% behaved as colonizers. One third of hospitalized patients with CPE isolation died within 30 days, regardless of whether they were colonized or infected.

CONCLUSIONS

We have observed an epidemiological change in the genotypes of our isolates along the study period. A thorough knowledge of the CPE's epidemiological distribution in each hospital is fundamental for optimizing antimicrobial chemotherapy.

Reduction of Inappropriate Antimicrobial Prescriptions in a Tertiary Neonatal Intensive Care Unit After Antimicrobial Stewardship Care Bundle Implementation

BACKGROUND

Our objective was to evaluate the appropriateness of antibiotic prescriptions in the neonatal intensive care unit using standardized criteria and determine the effects of an antimicrobial stewardship program (ASP) on patterns of antibiotic usage.

METHODS

A retrospective audit of antibiotic use from July 2010 to June 2013 was conducted, focusing on prescriptions of vancomycin, cefotaxime, meropenem and linezolid for >3 calendar-days. We evaluated the appropriateness of each course of antibiotic treatment based on the Centers for Disease Control and Prevention 12-Step Guidelines to Prevent Antimicrobial Resistance (steps 4, 6 and 9). An ASP was introduced in August 2014, and the same audit criteria were applied to review antimicrobial use in the subsequent 12 months.

RESULTS

In the pre-ASP era, 26.3%, 12.1%, 11.4% and 0% of meropenem, cefotaxime, vancomycin and linezolid courses, respectively, were inappropriate. The most common instance of inappropriate utilization included failure to use narrow-spectrum antimicrobials when appropriate. After the introduction of ASP program, 22.2%, 7.5%, 5.4% and 0% of meropenem, cefotaxime, vancomycin and linezolid courses, respectively, were inappropriate. The numbers of inappropriate antibiotic-days/1000 days of therapy with meropenem, cefotaxime and vancomycin changed from 1.89 to 1.96 [rate ratio (RR), 1.04 (0.70-1.52)], 3.56 to 1.73 [RR, 0.49 (0.33-0.71)] and 2.70 to 1.01 [RR, 0.37 (0.22-0.60)], respectively. In subgroup analysis, very low birth weight infants (birth weight, <1500 g) showed no improvement in the rates of inappropriate antibiotic prescriptions.

CONCLUSIONS

In this study, we found that ASP initiatives can be applied in neonatal populations to reduce inappropriate antimicrobial prescriptions, though a different approach may be needed among very low birth weight infants.

Whole Genome Sequencing detects Inter-Facility Transmission of Carbapenem-resistant Klebsiella pneumoniae

OBJECTIVES

To identify transmission patterns of Carbapenem-resistant Klebsiella pneumoniae infection during an outbreak at a large, tertiary care hospital and to detect whether the outbreak organisms spread to other facilities in the integrated healthcare network.

METHODS

We analyzed 71 K. pneumoniae whole genome sequences collected from clinical specimens before, during and after the outbreak and reviewed corresponding patient medical records. Sequence and patient data were used to model probable transmissions and assess factors associated with the outbreak.

RESULTS

We identified close genetic relationships among carbapenem-resistant K. pneumoniae isolates sampled during the study period. Transmission tree analysis combined with patient records uncovered extended periods of silent colonization in many study patients and transmission routes that were likely the result of asymptomatic patients transitioning between facilities.

CONCLUSIONS

Detecting how and where Carbapenem-resistant K. pneumoniae infections spread is challenging in an environment of rising prevalence, asymptomatic carriage and mobility of patients. Whole genome sequencing improved the precision of investigating inter-facility transmissions. Our results emphasize that containment of Carbapenem-resistant K. pneumoniae infections requires coordinated efforts between healthcare networks and settings of care that acknowledge and mitigate transmission risk conferred by undetected carriage and by patient transfers between facilities.

In vitro activity of flomoxef against extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Korea

To find an alternative regimen for the treatment of extended-spectrum β-lactamase (EBSL)-producing Enterobacteriaceae infections, we examined the in vitro activity of flomoxef against Escherichia coli and Klebsiella pneumoniae having CTX-M-1 group and/or CTX-M-9 group ESBLs. Boronic acid disk methods and polymerase chain reaction amplification were used to detect for ESBL, and AmpC β-lactamase and AmpC β-lactamase co-producers were excluded. Minimum inhibitory concentrations (MICs) were determined for flomoxef by broth microdilution. One hundred seventy-six isolates (E. coli, n = 93 and K. pneumoniae, n = 83) were analyzed for susceptibility test. A total of 94.3% (166/176) of isolates were susceptible to flomoxef (MIC₅₀/MIC₉₀ were 0.5/8 μg/mL); 98.9% of the ESBL-producing E. coli (MIC₅₀/MIC₉₀ were 1/4 μg/mL) and 89.2% of the ESBL-producing K. pneumoniae (MIC₅₀/MIC₉₀ were 0.5/16 μg/mL) were susceptible to flomoxef. Flomoxef has good in vitro activity against ESBL-producing E. coli and K. pneumoniae and could be considered as an alternative for infections caused by these organisms.

Knowledge and Practice of Pharmacists toward Antimicrobial Stewardship in Pakistan

Background: The irrational use, "over the counter supply", and unregulated supply chains of antimicrobials are contributing toward antimicrobial resistance. Antimicrobial stewardship programs regulate antimicrobials usage to prevent resistance and reduce health care burden. Objective: To assess the knowledge and practice of pharmacists' working in various healthcare settings toward antimicrobial stewardship in Pakistan. Method: A cross-sectional study was conducted among pharmacists working in different sectors between March to June 2017. Results: A total of 181 pharmacists participated, of whom (n = 145, 80.1%) were males. The majority of participants were in the 20⁻30 age group (n = 147, 81.2%) and hold Doctor of Pharmacy degrees. More than 80% of pharmacists agreed that "antimicrobial stewardship is essential to improve patient care"; while (n = 159, 87.8%) pharmacists agreed that "pharmacist should be trained on the use of antimicrobial". Close to 90% of pharmacists agreed that "adequate training should be provided to pharmacists on antimicrobial use". Regarding the practice of antimicrobial stewardship, (n = 72, 39.8%) pharmacists often/always "make efforts to prevent or reduce the transmission of infections within the community"; (n = 58, 32%) pharmacists never "dispense antimicrobials without a prescription"; and (n = 60, 32%) pharmacist often/always "communicate with prescribers if unsure about the appropriateness of an antibiotic prescription". Conclusions: Increased antimicrobial stewardship efforts can both optimize the treatment of infections and reduce adverse events associated with antibiotic use. Pharmacists in Pakistan have good knowledge and adopt positive practices toward antimicrobial stewardship. Pharmacist and other health care professionals should collaborate within multi-disciplinary teams to reduce the problem of antimicrobial resistance and improve the quality of life of patients.

Nontoxic Three-Part Combination Local Wound Therapy to Eradicate Carbapenem-Resistant Klebsiella pneumoniae

This case report describes eradication of carbapenem-resistant Klebsiella pneumoniae from an ischial pressure injury in a patient who underwent a 3-week course of nontoxic three-part combination local wound therapy. With this therapy, providers prevented systemic spread of this multidrug-resistant pathogen and avoided the nephrotoxicity associated with conventional triple antibiotic therapy.

Management of bacterial and fungal infections in end stage liver disease and liver transplantation: Current options and future directions

Patients with liver cirrhosis are susceptible to infections due to various mechanisms, including abnormalities of humoral and cell-mediated immunity and occurrence of bacterial translocation from the intestine. Bacterial infections are common and represent a reason for progression to liver failure and increased mortality. Fungal infections, mainly caused by Candida spp., are often associated to delayed diagnosis and high mortality rates. High level of suspicion along with prompt diagnosis and treatment of infections are warranted. Bacterial and fungal infections negatively affect the outcomes of liver transplant candidates and recipients, causing disease progression among patients on the waiting list and increasing mortality, especially in the early post-transplant period. Abdominal, biliary tract, and bloodstream infections caused by Gram-negative bacteria [e.g., Enterobacteriaceae and Pseudomonas aeruginosa (P. aeruginosa)] and Staphylococcus spp. are commonly encountered in liver transplant recipients. Due to frequent exposure to broad-spectrum antibiotics, invasive procedures, and prolonged hospitalizations, these patients are especially at risk of developing infections caused by multidrug resistant bacteria. The increase in antimicrobial resistance hampers the choice of an adequate empiric therapy and warrants the knowledge of the local microbial epidemiology and the implementation of infection control measures. The main characteristics and the management of bacterial and fungal infections in patients with liver cirrhosis and liver transplant recipients are presented.

Risk factors for mortality among carbapenem-resistant enterobacteriaceae carriers with focus on immunosuppression

OBJECTIVES

To identify risk factors for mortality in a cohort of carbapenem-resistant enterobacteriaceae (CRE) carriers, focusing on immunosuppression and other risk factors known at the time of CRE carriage detection.

METHODS

We prospectively followed all new and known CRE carriers admitted between June 2016 and June 2017 to a single tertiary center in Israel. Patients were included in the study after confirmation of the carrier state. Demographic and clinical data were documented on admission or CRE acquisition and patients were followed prospectively post-discharge until January 2018 or death. Risk factors for mortality known at the time of the first encounter with a CRE carrier were sought. Adjusted hazard ratios (HR) for mortality at end of follow-up with 95% confidence intervals (CI) were assessed using Cox regression analysis.

RESULTS

A total of 115 patients were included in the analysis. During the study period, 66 (57.4%) patients died. Immunosuppression was associated with mortality (HR 1.95, CI 95% 1.12-3.44), adjusted to the Charlson co-morbidity score, functional status, chronic renal disease and Klebsiella pneumonia CRE, the latter three also significantly associated with mortality. CRE bacteremia occurred among 24 (20.9%) carriers during follow up, more frequently among immunosuppressed patients and was significantly associated with mortality at end of follow-up (p = 0.015).

CONCLUSION

Immunosuppression is independently associated with mortality among CRE carriers, possibly related to CRE bacteremia that is frequent among these patients. Further research is needed on interventions to prevent deaths among CRE carriers.

The Infinity War: How to Cope with Carbapenem-resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) are now spread worldwide. In Korea, the number of CRE isolation is rapidly increasing, and impending endemicity is a concern. To cope well with CRE, thorough infection control, such as active surveillance, early detection, strict contact precaution, cleaning the environment, and antibiotic stewardship is very important. Therapeutic options include polymyxin, tigecycline, fosfomycin or the combination of them with carbapenem, which is currently the mainstay of treatment. In addition, various combination regimens with new carbapenemase inhibitors such as avibactam, vaborbactam, or relebactam, and other classes of antimicrobials such as plazomicin and siderophore cephalosporin are in the process of evaluation.

[Risk factors and clinical evolution of carbapenemase-producing Klebsiella pneumoniae infections in a university hospital in Spain. Case-control study]

OBJECTIVE

Carbapenemase-producing Enterobacterias is a global health hazard due to their ease of transmission, difficulty of treatment, and their personal and economic impact. We analyze the factors associated with an increased risk of infection by Klebsiella pneumoniae carbapenemase-producing bacteria (KPC) and factors related to poor prognosis.

METHODS

We designed a case-control study. KPC isolates were taken during an outbreak in a hospital in Madrid. A logistic regression was performed with the main variables.

RESULTS

Sixteen cases of clinically documented infections were isolated. Overall mortality rates in the cases group was 25%. The most frequent location was blood (37.5%) followed by urine (25%). All but one were OXA-48. Regarding factors related to an increased risk of developing infection, only previous exposure to antibiotics presented statistical significance difference OR 13 (2.40-70.46). With respect to the overall mortality, the presence of pneumonia OR 25 (1.93-323.55) or the use of invasive mechanical ventilation was associated with greater risk 15 OR 33 (1.92-122.8) For attributable mortality only invasive ventilation had a significant association OR 18 (1.48-218.95).

CONCLUSIONS

Exposure to previous antibiotics is an independent risk factor for developing KPC infection, adjusted for all other clinical and demographic variables. Risk factors such as the presence of pneumonia or the use of invasive mechanical ventilation were associated with a worse prognosis in terms of overall and attributable mortality.

Risk Factors for Carbapenem Resistant Klebsiella pneumoniae Hospital Infection in the Intensive Care Unit

Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) has become a major threat to patients in hospitals, increasing mortality, length of stay and costs.

The aim of this study was to discover risk factors for the development of hospital infections (HIs) caused by CR-Kp.

A prospective cohort study was conducted in the Medical-Surgical Intensive Care Unit of the Clinical Centre in Kragujevac, Kragujevac, Serbia, from January 1, 2011, to December 31, 2015. The “cases” were patients with HIs caused by CR-Kp, while the “controls” were patients infected with carbapenem-sensitive Klebsiella pneumoniae (CS-Kp). The significance of multiple putative risk factors for HIs caused by CR-Kp was tested using multivariate logistic regression.

Although univariate analyses pointed to many risk factors, with a significant influence on the occurrence of hospital CR-Kp infections, the multivariate logistic regression identified five independent risk factors: use of mechanical ventilation (OR=6.090; 95% CI=1.030-36.020; p=0.046); length of antibiotic therapy before HIs (days) (OR=1.080; 95% CI=1.003-1.387; p=0.045); previous use of carbapenems (OR=7.005; 95% CI=1.054-46.572; p=0.044); previous use of ciprofloxacin (OR=20.628; 95% CI=2.292-185.687; p=0.007) and previous use of metronidazole (OR=40.320; 95% CI=2.347-692.795; p=0.011)

HIs caused by CR-Kp are strongly associated with the use of mechanical ventilation and the duration of the previous use of certain antibiotics (carbapenems, ciprofloxacin and metronidazole).

Fecal carriage of carbapenem-resistant Enterobacteriaceae and risk factor analysis in hospitalised patients: A single centre study from India

PURPOSE

Carbapenem-resistant Enterobacteriaceae (CRE) have emerged and disseminated widely causing a variety of infections. In India, the carriage of CRE in hospitalised patients has not been well-studied. Therefore, we conducted the present study to observe gut carriage rate of CRE in patients admitted to our tertiary care hospital.

METHODS

A total of 232 faecal swabs collected from consecutive stool samples from admitted patients were inoculated on ChromID extended spectrum β-lactamase plates and members of Enterobacteriaceae family were subjected to antibiotic susceptibility as per the Clinical Laboratory Standards Institute guidelines. Polymerase chain reaction for blaVIM, blaKPC, blaIMPand blaNDM-1 genes was performed. CRE was identified if the isolates showed resistance to either imipenem or meropenem or showed the presence of resistant genes. Risk factors of patients with or without CRE colonisation were also analysed.

RESULTS

A total of 232 faecal swabs yielded 252 Enterobacteriaceae isolates, of which 49 isolates from 42 patients showed the presence of CRE (occurrence 42/232; 18.1%); 27 isolates from 22 patients carried blaNDM-1, whereas 20 isolates from 17 patients possessed blaVIMgene. No isolate was positive for blaKPCand blaIMPgenes. The CRE was common in both intensive care units (38.4%) and wards (46%) which may reflect the excessive use of broad-spectrum antibiotics in both these settings. The CRE was also found to have a significantly higher antimicrobial resistance as compared to non-CRE isolates. The logistic regression analysis of significance showed the presence of any indwelling device (P = 0.049) and nasogastric tube (P = 0.043) as independent risk factors for acquiring gut colonisation.

CONCLUSIONS

The study is the first from India to show high CRE carriage in patients admitted to a tertiary care centre and emphasises the need of strict antimicrobial stewardship implementation in hospitals to prevent dissemination of multidrug-resistant CRE.

Changes in Antimicrobial Usage Patterns in Korea: 12-Year Analysis Based on Database of the National Health Insurance Service-National Sample Cohort

National antimicrobial usage and prescription patterns during the 12 years from 2002 to 2013 were analyzed using the National Health Insurance Service-National Sample Cohort. Antimicrobial usage was analyzed by major illness, sex, age, area of residence, income rank, diagnosis, and type of medical institution for each year. Total antimicrobial prescriptions increased from 15.943 daily defined dose (DDD)/1,000 inhabitants/day in 2002 to 24.219 in 2013. In 2013, 72% of total prescriptions were administered in clinics. Antimicrobials were most frequently prescribed to children younger than 10 years, followed by adults aged 70 years or older and those aged 60-69 years. Penicillins and cephems were the most popular classes of antimicrobial used. In 2013, 48% of total antibiotic usage (11.683 DDD/1,000 inhabitants/day) was due to respiratory diseases. After the Korean government has implemented a series of healthcare policies, antibiotic prescription decreased for the treatment of upper respiratory infection, the causative agents are mostly viruses.

Active screening and interfacility communication of carbapenem-resistant Enterobacteriaceae (CRE) in a tertiary-care hospital

BACKGROUND

Hospitals may implement admission screening cultures and may review transfer documentation to identify patients colonized with carbapenem-resistant Enterobacteriaceae (CRE) to implement isolation precautions; however, outcomes and logistical considerations have not been well described.

METHODS

At an academic hospital in Chicago, we retrospectively studied the implementation and outcomes of CRE admission screening from 2013 to 2016 during 2 periods. During period 1, we implemented active CRE rectal culture screening for all adults patients admitted to intensive care units (ICUs) and for those transferred from outside facilities to general wards. During period 2, screening was restricted only to adults transferred from outside facilities. For a subset of transferred patients who were previously reported to the health department as CRE positive, we reviewed transfer paperwork for appropriate documentation of CRE.

RESULTS

Overall, 11,757 patients qualified for screening; rectal cultures were performed for 8,569 patients (73%). Rates of CRE screen positivity differed by period, previous facility type (if transferred), and current inpatient location. A higher combined CRE positivity rate was detected in the medical and surgical ICUs among period 2 patients (3.3%) versus all other ward-period comparisons (P<.001). Among 13 transferred patients previously known to be CRE colonized, appropriate CRE transfer documentation was available for only 4 patients (31%).

CONCLUSIONS

Active screening for CRE is feasible, and screening patients transferred from outside facilities to the medical or surgical ICU resulted in the highest screen positivity rate. Furthermore, CRE carriage was inconsistently documented in transfer paperwork, suggesting that admission screening or enhanced inter-facility communication are needed to improve the identification of CRE-colonized patients.

In Vitro Antimicrobial Activity of Green Synthesized Silver Nanoparticles Against Selected Gram-negative Foodborne Pathogens

Silver nanoparticles (AgNPs) used in this study were synthesized using pu-erh tea leaves extract with particle size of 4.06 nm. The antibacterial activity of green synthesized AgNPs against a diverse range of Gram-negative foodborne pathogens was determined using disk diffusion method, resazurin microtitre-plate assay (minimum inhibitory concentration, MIC), and minimum bactericidal concentration test (MBC). The MIC and MBC of AgNPs against Escherichia coli, Klebsiella pneumoniae, Salmonella Typhimurium, and Salmonella Enteritidis were 7.8, 3.9, 3.9, 3.9 and 7.8, 3.9, 7.8, 3.9 μg/mL, respectively. Time-kill curves were used to evaluate the concentration between MIC and bactericidal activity of AgNPs at concentrations ranging from 0×MIC to 8×MIC. The killing activity of AgNPs was fast acting against all the Gram-negative bacteria tested; the reduction in the number of CFU mL^-1 was >3 Log₁₀ units (99.9%) in 1–2 h. This study indicates that AgNPs exhibit a strong antimicrobial activity and thus might be developed as a new type of antimicrobial agents for the treatment of bacterial infection including multidrug resistant bacterial infection.

Association Between Carbapenem Resistance and Mortality Among Adult, Hospitalized Patients With Serious Infections Due to Enterobacteriaceae: Results of a Systematic Literature Review and Meta-analysis

This study quantified mortality associated with serious infections caused by carbapenem-resistant (CRE) and carbapenem-susceptible Enterobacteriaceae (CSE). A systematic literature review was conducted, evaluating outcomes in hospitalized patients with CRE infections from a blood, urinary, pulmonary, or intra-abdominal source. A meta-analysis (MA) calculating odds ratios (ORs) for mortality was performed. Twenty-two studies met the criteria for inclusion in the MA: 12 included mortality data for CRE vs CSE populations. Compared with CSE, CRE was associated with a significantly higher risk of overall mortality (OR, 3.39; 95% confidence interval [CI], 2.35-4.89), as was monotherapy (vs combination therapy) treatment of patients with CRE infections (OR, 2.19; 95% CI, 1.00-4.80). These results document the increased mortality associated with serious CRE infections compared with CSE infections among hospitalized adults. It will be important to reevaluate the mortality in CRE and CSE populations, especially among patients who receive early appropriate therapy, as new antibiotics become available.

Prevalence of carbapenemase-producing organisms at the Kidney Center of Rawalpindi (Pakistan) and evaluation of an advanced molecular microarray-based carbapenemase assay

AIM

A DNA microarray-based assay for the detection of antimicrobial resistance (AMR) genes was used to study carbapenemase-producing organisms at the Kidney Center of Rawalpindi, Pakistan.

METHODS

The evaluation of this assay was performed using 97 reference strains with confirmed AMR genes. Testing of 7857 clinical samples identified 425 Gram-negative bacteria out of which 82 appeared carbapenem resistant. These isolates were analyzed using VITEK-2 for phenotyping and the described AMR assay for genotyping.

RESULTS

The most prevalent carbapenemase gene was blaNDM and in 12 isolates we detected two carbapenemase genes (e.g., blaNDM/blaOXA-48).

CONCLUSION

Our prevalence data from Pakistan show that - as in other parts of the world - carbapenemase-producing organisms with different underlying resistance mechanisms are emerging, and this warrants intensified and constant surveillance.

Facilitators and Barriers to Antibiotic Stewardship: A Qualitative Study of Pharmacists' Perspectives

Background: The Veterans Affairs (VA) is a leader in the implementation and advancement of antibiotic stewardship programs throughout the nation. The Centers for Disease Control and Prevention (CDC) has also led national antibiotic stewardship efforts and has outlined core elements to improve antibiotic use in hospitals, long-term care, and outpatient settings. Many facilities still face challenges to the implementation and maintenance of successful programs, particularly in nonacute care settings. The objective of this study was to identify barriers and facilitators to antibiotic stewardship within the VA medical centers through qualitative interviews with pharmacists. Methods: Eight semi-structured telephone interviews were conducted with pharmacists from 6 VA medical centers within VA New England Healthcare System. Pharmacist respondents were either pharmacy champions (for medical centers with established programs) or pharmacists with responsibilities in making antibiotic recommendations (locations without established programs). All interviews were audio recorded and transcribed verbatim. NVivo 8 was used for data coding and analysis. Results: Pharmacists from all 8 medical centers were contacted for interviews and pharmacists from 6 medical centers agreed to interviews (75% VA New England medical center participation). Three main themes regarding antibiotic stewardship were identified from the interviews with pharmacists. Respondents described the importance of (1) a supportive organizational culture, (2) protected time for antibiotic stewardship, and (3) a cohesive organizational structure in the success of antibiotic stewardship programs. Conclusions: Our findings support the CDC core elements for antibiotic stewardship, in particular the importance of leadership commitment in the creation of a culture that supports antibiotic stewardship and in ensuring staff are given sufficient time for antibiotic stewardship efforts. Although a strong supportive culture has been built, strategies focused on fostering increased protected time for antibiotic stewardship and a cohesive organizational structure may be helpful in advancing and sustaining successful antibiotic stewardship programs that improve patient outcomes.

Risk factors for carbapenem-resistant K. pneumoniae bloodstream infection and predictors of mortality in Chinese paediatric patients

BACKGROUND

Bloodstream infections (BSI) caused by carbapenem-resistant K. pneumoniae (CRKP) are associated with high rates of morbidity and mortality. Early identification of patients at highest risk is very important. The aim of this study was to describe the clinical characteristics and mortality of K. pneumoniae BSI and to identify risk factors associated with CRKP BSI among paediatric patients.

METHODS

From January 2011 to December 2014, a retrospective case-control study was conducted at Beijing Children's Hospital, China. Risk factors for CRKP BSI and for K. pneumoniae BSI-related death were evaluated. Patients with BSI caused by K. pneumoniae were identified from the microbiology laboratory database. Data regarding demographic, microbiological and clinical characteristics, therapy and outcome were collected from the medical records.

RESULTS

A total of 138 patients with K. pneumoniae BSI were enrolled, including 54 patients with CRKP BSI and 84 patients with carbapenem-susceptible K. pneumoniae (CSKP) BSI. Most of the BSI (114; 82.6%) were healthcare-associated, while the rest (24; 17.4%) were community-acquired. Hematologic malignancies (odds ratio (OR):4.712, [95% CI: 2.181-10.180], P <  0.001) and previous cephalosporin administration (OR: 3.427, [95% CI: 1.513-7.766], P = 0.003) were found to be associated with the development of CRKP BSI. 28-day mortality of K. pneumoniae BSI was 8.7%. Mechanical ventilation (OR:9.502, [95% CI: 2.098-43.033], P = 0.003), septic shock (OR:6.418, [95% CI: 1.342-30.686], P = 0.020), and isolation of CRKP (OR:9.171, [95% CI: 1.546-54.416], P = 0.015) were independent risk factors for 28-day mortality of K. pneumoniae BSI.

CONCLUSION

Hematologic malignancies and previous cephalosporin administration were associated with the development of CRKP BSI, while mechanical ventilation, septic shock and CRKP infection were independent mortality predictors for K. pneumoniae BSI. More attention should be paid to CRKP BSI in the paediatric population.

Epidemiology of carbapenem-resistant Klebsiella pneumoniae bloodstream infections after renal transplantation from donation after cardiac death in a Chinese hospital: a case series analysis

Background

Although the high mortality rates have been extensively reported worldwide, few studies have investigated the epidemiology of CRKP-BSIs in the early stage after kidney transplantation (KTx) from donation after cardiac death (DCD). We sought to describe the epidemiological and clinical characteristics of cases of carbapenem resistant Klebsiella pneumoniae bloodstream infections (CRKP-BSIs) in kidney transplantation recipients (KTRs) from DCD in our hospital.

Methods

A retrospective analysis of clinical data of CRKP-BSIs in KTRs admitted to a Chinese hospital in Beijing, China, between January 1, 2012 and December 31, 2016 was performed. The annual percentage of patients with CRKP, the annual number of total KTRs and KTRs from DCD were determined. The genetic relatedness of the strains was determined by polymerase chain reaction and pulse field gel electrophoresis (PFGE).

Results

During the study period, there were total 947 KTRs in our hospital, including 275 KTRs from DCD. Five incidences of CRKP-BSIs in KTRs were identified, and two of them (Case 1,3) from the same foreign hospital. The incidence of CRKP-BSIs in the early stage (within 3 months) following kidney transplantation (KTx) from DCD was about 1.1% (3/275). In Case 1–3 and 5, the rupture of renal transplant artery was presented on the 40th, 16th, 43th and 74th day after KTx, and in Case 4, the thrombus of renal transplant artery was presented on the 13th day after KTx. Three cases (Case 1,2,5) occurring pneumothorax on the 45th, 51th and 32th day after KTx. Four cases (Case 1–4) received the excision of the transplanted kidney for the treatment. Polymerase chain reaction showed the bands for case 2 were distinctive from other cases. Pulse field gel electrophoresis showed mainly three clusters of the bands for all the isolates.

Conclusions

During the study period, we observed an increase in the occurrence of CRKP-BSIs among KTRs from DCD in our hospital. We demonstrated that rupture/thrombus of the renal transplant artery was associated with CRKP-BSI in the early stage after KTx from DCD. Albeit the low incidence of CRKP-BSI (1.1%) after KTx from DCD, the high mortality (4/5) had been observed from the prognosis of the patients. Thorough surveillance of DCD donors, early identification of CRKP-BSI, necessary preventative measurements and use of appropriate treatments should be the strategy for CRKP-BSI in the early stage after KTx from DCD.

Electronic supplementary material

The online version of this article (10.1186/s13756-018-0355-8) contains supplementary material, which is available to authorized users.

The Epidemiology, Evolution, and Treatment of KPC-Producing Organisms

PURPOSE OF REVIEW

The purpose of this review is to investigate the evolution and epidemiology of Klebsiella pneumoniae carbapenemase (KPC)-producing organisms and the current and future treatment options for infections caused by KPC-producing isolates.

RECENT FINDINGS

The emergence of resistance in Enterobacteriaceae producing carbapenemases globally has increased the challenges in treating infections caused by these organisms. One of the prominent mechanisms of resistance is the production of KPC enzymes. Infections caused by organisms producing KPCs have limited treatment options and are associated with poor clinical outcomes. The rapid rise of KPC-producing organisms necessitated the use of drugs with pharmacokinetic and toxicity limitations, including polymyxins, tigecycline, fosfomycin, and aminoglycosides. The availability of new beta-lactamase inhibitor combinations that are effective against KPC-producing organisms represent an advance in safety and efficacy. Several agents are currently being studied that have activity against KPC-producing organisms and appear to represent promising additions to our armamentarium. KPC-producing organisms cause infections with high morbidity and mortality. Limited treatment options are available, though new therapies have been developed. Pipeline agents are likely to have a place in therapy for the treatment of infections caused by KPC-producing isolates.

Treatment with Atorvastatin Provides Additional Benefits to Imipenem in a Model of Gram-Negative Pneumonia Induced by Klebsiella pneumoniae in Mice

The clinical pathogen Klebsiella pneumoniae is a relevant cause of nosocomial infections, and resistance to current treatment with carbapenem antibiotics is becoming a significant problem. Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) used for controlling plasma cholesterol levels. There is clinical evidence showing other effects of statins, including decrease of lung inflammation. In the current study, we show that pretreatment with atorvastatin markedly attenuated lung injury, which was correlated with a reduction in the cellular influx into the alveolar space and lungs and downmodulation of the production of proinflammatory mediators in the initial phase of infection in C57BL/6 mice with K. pneumoniae However, atorvastatin did not alter the number of bacteria in the lungs and blood of infected mice, despite decreasing local inflammatory response. Interestingly, mice that received combined treatment with atorvastatin and imipenem displayed better survival than mice treated with vehicle, atorvastatin, or imipenem alone. These findings suggest that atorvastatin could be an adjuvant in host-directed therapies for multidrug-resistant K. pneumoniae, based on its powerful pleiotropic immunomodulatory effects. Together with antimicrobial approaches, combination therapy with anti-inflammatory compounds could improve the efficiency of therapy during acute lung infections.

A systematic review of the epidemiology of carbapenem-resistant Enterobacteriaceae in the United States

Background

Carbapenem-resistant Enterobacteriaceae (CRE) pose an urgent public health threat in the United States. An important step in planning and monitoring a national response to CRE is understanding its epidemiology and associated outcomes. We conducted a systematic literature review of studies that investigated incidence and outcomes of CRE infection in the US.

Methods

We performed searches in MEDLINE via Ovid, CDSR, DARE, CENTRAL, NHS EED, Scopus, and Web of Science for articles published from 1/1/2000 to 2/1/2016 about the incidence and outcomes of CRE at US sites.

Results

Five studies evaluated incidence, but many used differing definitions for cases. Across the entire US population, the reported incidence of CRE was 0.3–2.93 infections per 100,000 person-years. Infection rates were highest in long-term acute-care (LTAC) hospitals. There was insufficient data to assess trends in infection rates over time. Four studies evaluated outcomes. Mortality was higher in CRE patients in some but not all studies.

Conclusion

While the incidence of CRE infections in the United States remains low on a national level, the incidence is highest in LTACs. Studies assessing outcomes in CRE-infected patients are limited in number, small in size, and have reached conflicting results. Future research should measure a variety of clinical outcomes and adequately adjust for confounders to better assess the full burden of CRE.

Electronic supplementary material

The online version of this article (10.1186/s13756-018-0346-9) contains supplementary material, which is available to authorized users.

A retrospective, comparative analysis of risk factors and outcomes in carbapenem-susceptible and carbapenem-nonsusceptible Klebsiella pneumoniae bloodstream infections: tigecycline significantly increases the mortality

Background

Carbapenem-nonsusceptible Klebsiella pneumoniae (CnSKP) is rapidly emerging as a life-threatening nosocomial infection. The efficacy of tigecycline in the treatment of bloodstream infections (BSIs) remains controversial.

Methods

Data from a total of 428 patients with carbapenem-susceptible Klebsiella pneumoniae (CSKP) and CnSKP BSIs were collected at a single center between January 2013 and December 2015. A three-part analysis was conducted to identify the risk factors associated with CnSKP, explore prognosis, and evaluate treatments.

Results

Data from 428 patients with Klebsiella pneumoniae (KP) BSIs were included, 31.5% (n=135) of them with CnSKP. Multivariate analysis showed that prior hospitalization, urinary catheterization, the use of immunosuppressive agents, prior use of antibiotics, pulmonary disease, and high Acute Physiology and Chronic Health Evaluation (APACHE) II scores were independent risk factors for CnSKP-BSIs. The 30-day mortality was higher in patients with CnSKP than in those with CSKP (58.5% vs 15.4%; P<0.001). In patients with KP-BSIs, neutropenia, multiple organ dysfunction, respiratory failure, CnSKP infection, high APACHE II score, and tigecycline therapy were independently associated with higher mortality risk. Among patients whose APACHE II score was <15, higher mortality rates were observed in patients treated with tigecycline than in those treated with other antibiotics (45.3% vs 7.7%; P<0.001). Central venous catheterization, multiple organ dysfunction, and high APACHE II scores were independent risk factors for death from CnSKP.

Conclusion

A significant increase in the incidence of CnSKP-BSIs was observed during the study period, with a higher mortality rate found in these patients. Exposure to carbapenems and severe illness were independent risk factors for the development of CnSKP-BSIs, and tigecycline therapy resulted in a significant increase in mortality.

Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 Klebsiella pneumoniae

Carbapenem-resistant Enterobacteriaceae, including K. pneumoniae, are a major health care concern worldwide because they cause a wide range of infection and are resistant to all or nearly all antibiotics. To cause infection, these bacteria must acquire iron, and a major mechanism of acquiring iron is by secreting a molecule called enterobactin that strips iron from host proteins. However, a subset of carbapenem-resistant K. pneumoniae strains that lack a portion of the entS gene that is required for enterobactin secretion was recently discovered. To understand how these mutant strains obtain iron, we studied their transcriptional responses, bacterial growth, and enterobactin secretion under iron-limited conditions. We found that strains both with mutated and intact entS genes grow under iron-limiting conditions, secrete enterobactin, and utilize an alternate iron source, hemin, for growth. Our data indicate that carbapenem-resistant K. pneumoniae can use varied methods for iron uptake during infection.

Klebsiella pneumoniae is rapidly acquiring resistance to all known antibiotics, including carbapenems. Multilocus sequence type ST258 (sequence type 258), carrying a gene encoding the K. pneumoniae carbapenemase (bla_KPC) on a transmissible plasmid, is the most prevalent carbapenem-resistant Enterobacteriaceae (CRE) in the United States and has disseminated worldwide. Previously, whole-genome sequencing identified core genome single nucleotide variants that divide ST258 into two distinct clades, ST258a and ST258b. Furthermore, a subset of ST258b strains have a 347-base deletion within the enterobactin (Ent) exporter gene entS. Despite the predicted inability of these strains to secrete the siderophore Ent, this clade is prevalent among clinical isolates, indicating that a full-length entS gene is not necessary for infection. To compare the transcriptional responses of ST258 subtypes to iron limitation, we performed transcriptome sequencing (RNA-Seq) in minimal medium alone or supplemented with iron or human serum and measured gene expression patterns. Iron limitation induced differential expression of distinct iron acquisition pathways when comparing ST258a and ST258b strains, including the upregulation of the hemin transport operon in entS partial deletion isolates. To measure how K. pneumoniae strains vary in iron chelation and siderophore production, we performed in vitro chrome azurol S (CAS) and Arnow assays as well as mass spectrometry. We determined that both ST258a and ST258b strains grow under iron-depleted conditions, can utilize hemin for growth, and secrete Ent, despite the partial entS deletion in a subset of ST258b strains. All carbapenem-resistant (CR) K. pneumoniae strains tested were susceptible to growth inhibition by the Ent-sequestering innate immune protein lipocalin 2.

IMPORTANCE Carbapenem-resistant Enterobacteriaceae, including K. pneumoniae, are a major health care concern worldwide because they cause a wide range of infection and are resistant to all or nearly all antibiotics. To cause infection, these bacteria must acquire iron, and a major mechanism of acquiring iron is by secreting a molecule called enterobactin that strips iron from host proteins. However, a subset of carbapenem-resistant K. pneumoniae strains that lack a portion of the entS gene that is required for enterobactin secretion was recently discovered. To understand how these mutant strains obtain iron, we studied their transcriptional responses, bacterial growth, and enterobactin secretion under iron-limited conditions. We found that strains both with mutated and intact entS genes grow under iron-limiting conditions, secrete enterobactin, and utilize an alternate iron source, hemin, for growth. Our data indicate that carbapenem-resistant K. pneumoniae can use varied methods for iron uptake during infection.

Genomic Analysis of a Pan-Resistant Isolate of Klebsiella pneumoniae, United States 2016

Antimicrobial resistance is a threat to public health globally and leads to an estimated 23,000 deaths annually in the United States alone. Here, we report the genomic characterization of an unusual Klebsiella pneumoniae, nonsusceptible to all 26 antibiotics tested, that was isolated from a U.S. patient. The isolate harbored four known beta-lactamase genes, including plasmid-mediated bla_NDM-1 and bla_CMY-6, as well as chromosomal bla_CTX-M-15 and bla_SHV-28, which accounted for resistance to all beta-lactams tested. In addition, sequence analysis identified mechanisms that could explain all other reported nonsusceptibility results, including nonsusceptibility to colistin, tigecycline, and chloramphenicol. Two plasmids, IncA/C2 and IncFIB, were closely related to mobile elements described previously and isolated from Gram-negative bacteria from China, Nepal, India, the United States, and Kenya, suggesting possible origins of the isolate and plasmids. This is one of the first K. pneumoniae isolates in the United States to have been reported to the Centers for Disease Control and Prevention (CDC) as nonsusceptible to all drugs tested, including all beta-lactams, colistin, and tigecycline.

Antimicrobial resistance is a major public health threat worldwide. Bacteria that are nonsusceptible or resistant to all antimicrobials available are of major concern to patients and the public because of lack of treatment options and potential for spread. A Klebsiella pneumoniae strain that was nonsusceptible to all tested antibiotics was isolated from a U.S. patient. Mechanisms that could explain all observed phenotypic antimicrobial resistance phenotypes, including resistance to colistin and beta-lactams, were identified through whole-genome sequencing. The large variety of resistance determinants identified demonstrates the usefulness of whole-genome sequencing for detecting these genes in an outbreak response. Sequencing of isolates with rare and unusual phenotypes can provide information on how these extremely resistant isolates develop, including whether resistance is acquired on mobile elements or accumulated through chromosomal mutations. Moreover, this provides further insight into not only detecting these highly resistant organisms but also preventing their spread.

Occurrence and Characterization of Carbapenemase-Producing Enterobacteriaceae in a Tunisian Hospital

Carbapenem-resistant Enterobacteriaceae have become of particular concern, since they were quickly disseminated in various areas in the world. The aim of the study was to investigate the prevalence of carbapenemase production among clinical isolates of Enterobacteriaceae recovered from the Military Hospital of Tunisia. Bacterial isolates (n = 125) were recovered from patients in diverse services from March 2014 to February 2016 and identified by Vitek II Compact^®. The multiplex PCR for bla_VIM, bla_IMP, bla_NDM, bla_KPC, and bla_OXA-48 with subsequent amplicon detection by reverse hybridization was performed with the Hyplex SuperBug ID test system (AmplexDiagnostics GmbH, Gars-Bahnhof, Germany). The 125 strains showed resistance to carbapenems of which 102 strains (81.6%) were carbapenemase-producing Enterobacteriaceae and were identified as Klebsiella pneumoniae (85.2%), Enterobacter cloacae (9.8%), Escherichia coli (2.9%), Providencia stuartii (0.9%) and Enterobacter aerogenes (0.9%). These strains were isolated mainly from blood, anal, and urine samples. Patients were mainly hospitalized in the intensive care units, surgery, and medical services. All strains were resistant to ertapenem (100%) and 55.8% showed resistance to imipenem. Carbapenemases genes detected in our study were as follows: bla_OXA-48 (84 isolates), bla_NDM-1 (8 isolates), bla_OXA-48 + bla_VIM (5 isolates), and bla_OXA-48 + bla_NDM-1 (5 isolates). Our research provides epidemiological data showing the quick spread of carbapenem-resistant bacteria in our region, which calls for new surveillance strategies and strict hygiene rules.

Clinical Significance of Gastrointestinal Carriage of Klebsiella Pneumoniae-Producing Extended-Spectrum Beta-Lactamases in Kidney Graft Recipients

The burden of Klebsiella pneumoniae (KP) producing extended-spectrum beta-lactamases (ESBL+) urinary tract infections (UTIs) is a growing problem after kidney transplantation (KTX). The study was aimed at evaluating the incidence of KP ESBL+ gut colonization in KTX recipients and its correlation with clinical outcomes with special regard to UTIs. The study included all KTX patients hospitalized in our department between January 2014 and December 2016. During this period 2018 KTX patients were admitted: 605 in 2014, 750 in 2015, and 663 in 2016, respectively. Screening for drug-multiresistant Enterobacteriaceae gut carriage was performed in 104 patients (2014), 122 (2015), and 166 (2016). In 2014, 2015, and 2016, 18 (17.3%), 26 (21.3%), and 30 (18.1%) patients had positive test results, and 44 (42.3%), 36 (29.5%), and 45 (27.4%) KTX patients were diagnosed with KP ESBL+ UTI. In 2014, KP ESBL+ UTI was diagnosed in 30 (34.9%) cases with negative anal swab and in 14 patients (77.8%) with positive test result (P = .0008). In 2015, KP ESBL+ UTI was diagnosed in 21 patients (21.9%) with negative anal swab and in 15 (57.7%) with positive test result (P = .0004). In 2016, KP ESBL+ UTI was diagnosed in 24 patients (17.8%) with negative anal swab and in 21 (72.4%) with positive test result (P = .000001). In conclusion, we have revealed a strong association between gut K. pneumoniae colonization, female sex, and MPA intake and KP ESBL+ urinary tract infections in kidney transplant recipients. Our results indicate the very important role of KP ESBL+ screening, while strategies of identified carriers require further research.

Factors associated to prevalence and treatment of carbapenem-resistant Enterobacteriaceae infections: a seven years retrospective study in three tertiary care hospitals

Background

The increasing incidence of carbapenem-resistant Enterobacteriaceae (CRE), has resulted in a difficult problem in the current clinical anti-infective treatment. We performed a retrospective analysis of prevalence and treatment for CRE infections patients.

Methods

This study was conducted in three tertiary care hospitals from January 1, 2010 to December 30, 2016. Baseline data, treatment, and outcomes were collected in patients with ventilator-associated bacterial pneumonia (VABP), bacteremia, complicated urinary tract infection (cUTI)/acute pyelonephritis (AP), hospital-acquired bacterial pneumonia (HABP), superficial wound infection (SWI), biliary tract infection (BTI), deep wound infection (DWI) and sterile body fluids infection (SBFI) due to CRE.

Results

One hundred twenty-four cases of CRE infection were identified: 31 VABP, 22 bacteremia, 18 cUTI/AP, 16 HABP, 16 SWI, 9 BTI, 7 DWI and 5 SBFI. The patient population had significant immunocompromised (33 of 124, 26.6%) and severe sepsis (43 of 124, 34.7%). The most common CRE pathogens were Klebsiella pneumoniae (84 of 124, 67.7%) and Enterobacter cloacae (24 of 124, 19.4%). And the production of IMP-type carbapenemase was the main antibiotic resistance mechanism. The majority of patients to take monotherapy for empiric therapy and dual therapy for direct treatment. Outcomes were universally poor (28-day mortality was 22.6%, 28 of 124) across all sites of infection.

Conclusions

We identified a large number of cases of CRE infection in 7 years from different parts, most of these pathogens have been confirmed to produce IMP-type carbapenemases. The retrospective analysis of cases of such bacterial infections will help to control future infections of these pathogens. Despite the high mortality rate, we still found that the selection of quinolone antibiotics can be effective in the treatment of CRE producing IMP type enzymes.

Carbapenem-Resistant Klebsiella pneumoniae Exhibiting Clinically Undetected Colistin Heteroresistance Leads to Treatment Failure in a Murine Model of Infection

Antibiotic resistance is a growing crisis and a grave threat to human health. It is projected that antibiotic-resistant infections will lead to 10 million annual deaths worldwide by the year 2050. Among the most significant threats are carbapenem-resistant Enterobacteriaceae (CRE), including carbapenem-resistant Klebsiella pneumoniae (CRKP), which lead to mortality rates as high as 40 to 50%. Few treatment options are available to treat CRKP, and the polymyxin antibiotic colistin is often the "last-line" therapy. However, resistance to colistin is increasing. Here, we identify multidrug-resistant, carbapenemase-positive CRKP isolates that were classified as susceptible to colistin by clinical diagnostics yet harbored a minor subpopulation of phenotypically resistant cells. Within these isolates, the resistant subpopulation became predominant after growth in the presence of colistin but returned to baseline levels after subsequent culture in antibiotic-free media. This indicates that the resistance was phenotypic, rather than due to a genetic mutation, consistent with heteroresistance. Importantly, colistin therapy was unable to rescue mice infected with the heteroresistant strains. These findings demonstrate that colistin heteroresistance may cause in vivo treatment failure during K. pneumoniae infection, threatening the use of colistin as a last-line treatment for CRKP. Furthermore, these data sound the alarm for use of caution in interpreting colistin susceptibility test results, as isolates identified as susceptible may in fact resist antibiotic therapy and lead to unexplained treatment failures.IMPORTANCE This is the first report of colistin-heteroresistant K. pneumoniae in the United States. Two distinct isolates each led to colistin treatment failure in an in vivo model of infection. The data are worrisome, especially since the colistin heteroresistance was not detected by current diagnostic tests. As these isolates were carbapenem resistant, clinicians might turn to colistin as a last-line therapy for infections caused by such strains, not knowing that they in fact harbor a resistant subpopulation of cells, potentially leading to treatment failure. Our findings warn that colistin susceptibility testing results may be unreliable due to undetected heteroresistance and highlight the need for more accurate and sensitive diagnostics.

Risk Factors for Carbapenem-Resistant Klebsiella pneumoniae Infection: A Meta-Analysis

AIMS

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection has been rapidly emerging as a life-threatening nosocomial disease in many countries. However, studies on the corresponding risk factors of CRKP infection showed inconsistent results. To resolve these inconsistencies, we conducted a meta-analysis of previous studies on the potential risk factors of CRKP infection. The results of this study could be used to develop CRKP infection prevention strategies.

METHODS

Relevant works were systematically searched from five electronic databases up to September 2016. Z-test was used to determine the significance of the pooled odds ratios (ORs). ORs and 95% confidence intervals were utilized to compare the risk factors of CRKP infection.

RESULTS

Sixteen studies that involved 3,627 participants were included in the meta-analysis. We identified the following risk factors that were associated with CRKP infection: (1) longer length of hospital stay (LOS) (OR = 12.92), (2) admission to intensive care unit (ICU) (OR = 2.48), (3) prior hospitalization (OR = 1.85), (4) longer days of ICU stay (OR = 4.58), (5) transplant recipient (OR = 2.01), (6) steroid use (OR = 1.43), (7) central venous catheter use (OR = 2.30), (8) mechanical ventilation (OR = 2.54), (9) presence of tracheostomy (OR = 3.63), (10) parenteral nutrition (OR = 2.38), (11) previous antibiotic use (OR = 3.31), and (12) exposure to carbapenems (OR = 4.01), (13) aminoglycosides (OR = 2.05), (14) glycopeptides (OR = 2.40), (15) quinolones (OR = 2.28), and (16) anti-pseudomonal penicillins (OR = 2.67).

CONCLUSIONS

Sixteen risk factors including longer LOS, admission to ICU, previous antibiotic use, and exposure to carbapenems were associated with the development of CRKP infection. Identification of modifiable risk factors could play an important role in the prevention of CRKP infection.

Multifactorial chromosomal variants regulate polymyxin resistance in extensively drug-resistant Klebsiella pneumoniae

Extensively drug-resistant Klebsiella pneumoniae (XDR-KP) infections cause high mortality and are disseminating globally. Identifying the genetic basis underpinning resistance allows for rapid diagnosis and treatment. XDR isolates sourced from Greece and Brazil, including 19 polymyxin-resistant and five polymyxin-susceptible strains, were subjected to whole genome sequencing. Seventeen of the 19 polymyxin-resistant isolates harboured variations upstream or within mgrB. The most common mutation identified was an insertion at nucleotide position 75 in mgrB via an ISKpn26-like element in the ST258 lineage and ISKpn13 in one ST11 isolate. Three strains acquired an IS1 element upstream of mgrB and another strain had an ISKpn25 insertion at 133 bp. Other isolates had truncations (C28STOP, Q30STOP) or a missense mutation (D29E) affecting mgrB. Complementation assays revealed all mgrB perturbations contributed to resistance. Missense mutations in phoQ (T281M, G385C) were also found to facilitate resistance. Several variants in phoPQ co-segregating with the ISKpn26-like insertion were identified as potential partial suppressor mutations. Three ST258 samples were found to contain subpopulations with different resistance-conferring mutations, including the ISKpn26-like insertion colonizing with a novel mutation in pmrB (P158R), both confirmed via complementation assays. These findings highlight the broad spectrum of chromosomal modifications which can facilitate and regulate resistance against polymyxins in K. pneumoniae.

Surveillance-guided selective digestive decontamination of carbapenem-resistant Enterobacteriaceae in the intensive care unit: A cost-effectiveness analysis

BACKGROUND

Clinical findings have shown effectiveness and safety of selective digestive decontamination (SDD) for eradication of carbapenem-resistant Enterobacteriaceae (CRE) in high-risk carriers. We aimed to evaluate the cost-effectiveness of SDD guided by CRE surveillance in the intensive care unit (ICU).

METHODS

Outcomes of surveillance-guided SDD (test-guided SDD) and no screening (control) in the ICU were compared by Markov model simulations. Model outcomes were CRE infection and mortality rates, direct costs, and quality-adjusted life year (QALY) loss. Model inputs were estimated from clinical literature. Sensitivity analyses were conducted to examine the robustness of base case results.

RESULTS

Test-guided SDD reduced infection (4.8% vs 5.0%) and mortality (1.8% vs 2.1%) rates at a higher cost ($1,102 vs $1,074) than the control group in base case analysis, respectively. Incremental cost per QALY saved (incremental cost-effectiveness ratio [ICER]) by the test-guided SDD group was $557 per QALY. Probabilistic sensitivity analysis showed that test-guided SDD was effective in saving QALYs in 100% of 10,000 Monte Carlo simulations, and cost-saving 59.1% of time. The remaining 40.9% of simulations found SDD to be effective at an additional cost, with ICERs accepted as cost-effective per the willingness-to-pay threshold.

CONCLUSIONS

Surveillance-guided SDD appears to be cost-effective in reducing CRE infection and mortality with QALYs saved.

Frequent Community Use of Antibiotics among a Low-Economic Status Population in Manila, the Philippines: A Prospective Assessment Using a Urine Antibiotic Bioassay

The widespread unregulated use of antibiotics without medical consultation contributes to the burden of antibiotic resistance in Southeast Asian countries. This study investigated antibiotic use before hospital consultation. In a prospective observational study from February 2, 2015, to July 2, 2015, we enrolled febrile patients attending the emergency room in San Lazaro Hospital, Manila, the Philippines. A urine sample was collected and a bioassay was used to detect antibiotic activity in urine using Bacillus stearothermophilus (ATCC7953), Escherichia coli (ATCC25922), and Streptococcus pyogenes (ATCC19615). Patients or caregivers reported their medication history, clinical information, and socioeconomic status. During the study period, 410 patients were enrolled. The median (interquartile range) age was 14 (7-23) years and 158 (39%) reported prior antibiotic use, predominantly a beta-lactam antibiotic. A total of 164 (40%, 95% confidence interval [CI]: 35-45) patients were urine bioassay positive with any of three organisms. The Bacillus assay was the most sensitive, detecting 162 (99%, 95% CI: 96-100) cases. Among bioassay positive patients, dengue (N = 91, 55%, 95% CI: 48-63) was the most frequent diagnosis, followed by other viral infections, including measles, rubella, and mumps (N = 17, 10%, 95% CI: 6-16). Patients with a positive bioassay were significantly more likely to be from the lowest-income group (adjusted odds ratio [AOR]: 1.7; 95% CI: 1.1-2.6) and required hospital admission (AOR: 2.1; 95% CI: 1.3-3.5). Unnecessary antibiotic use for febrile illnesses before hospital consultation is common in a low-income, highly populated urban community in Manila. Education targeting this group should be implemented to reduce unnecessary antibiotic use.

Prediction of imipenem-resistant microorganisms among the nosocomial critically ill patients with Gram-negative bacilli septicemia: a simple risk score

Objectives

The increasing number of reports on infections due to carbapenem-resistant Gram-negative bacilli (GNB) has raised concerns, because they have complicated empiric or guided antibiotic therapy for critically ill patients. We aimed to develop a scoring system to predict nosocomial imipenem-resistant GNB (IR-GNB) septicemia among the critically ill patients.

Materials and methods

The study included critically ill adult patients with nosocomial GNB septicemia at Kaohsiung Chang Gung Memorial Hospital (CGMH) in 2013-2015, and the scoring system for predicting IR-GNB septicemia was developed, followed by prospective validation conducted among patients at Linkou CGMH and Kaohsiung CGMH between January and June, 2016.

Results

In the development of the scoring system, 748 patients were included. The independent factors associated with IR-GNB septicemia were prior exposure (days) to carbapenems (adjusted odds ratio [aOR] per 1-day increase, 1.1; 1-3 days: 2 points, 4-6 days: 5 points, 7-9 days: 8 points, and ≥10 days: 13 points), use of mechanical ventilation (aOR 3.7; 5 points), prior colonization with IR-GNB strains (aOR 3.5; 5 points) within 30 days before the onset of GNB septicemia, and comorbid condition with chronic kidney disease (aOR 2.1; 3 points). The internal validation showed an area under the receiver operating characteristic curve (ROC) of 0.75; and an external validation among 314 patients showed similarly good performance (ROC 0.77). Youden's index indicated the score of ≥6 as the best cutoff value with sensitivity of 75% and specificity of 79%.

Conclusion

This scoring system might help clinicians stratify the risk for developing IR-GNB septicemia among critically ill patients and combined antibiotics may be used until antimicrobial de-escalation/adjustment is clearly indicated by the subsequently identified GNB and its susceptibility profile.

Effects of clinical pathway implementation on antibiotic prescriptions for pediatric community-acquired pneumonia

BACKGROUND

Italian pediatric antimicrobial prescription rates are among the highest in Europe. As a first step in an Antimicrobial Stewardship Program, we implemented a Clinical Pathway (CP) for Community Acquired Pneumonia with the aim of decreasing overall prescription of antibiotics, especially broad-spectrum.

MATERIALS AND METHODS

The CP was implemented on 10/01/2015. We collected antibiotic prescribing and outcomes data from children aged 3 months-15 years diagnosed with CAP from 10/15/2014 to 04/15/2015 (pre-intervention period) and from 10/15/2015 to 04/15/2016 (post-intervention period). We assessed antibiotic prescription differences pre- and post-CP, including rates, breadth of spectrum, and duration of therapy. We also compared length of hospital stay for inpatients and treatment failure for inpatients and outpatients. Chi-square and Fisher's exact test were used to compare categorical variables and Wilcoxon rank sum test was used to compare quantitative outcomes.

RESULTS

120 pre- and 86 post-intervention clinic visits were identified with a diagnosis of CAP. In outpatients, we observed a decrease in broad-spectrum regimens (50% pre-CP vs. 26.8% post-CP, p = 0.02), in particular macrolides, and an increase in narrow-spectrum (amoxicillin) post-CP. Post-CP children received fewer antibiotic courses (median DOT from 10 pre-CP to 8 post-CP, p<0.0001) for fewer days (median LOT from 10 pre-CP to 8 post-CP, p<0.0001) than their pre-CP counterparts. Physicians prescribed narrow-spectrum monotherapy more frequently than broad-spectrum combination therapy (DOT/LOT ratio 1.157 pre-CP vs. 1.065 post-CP). No difference in treatment failure was reported before and after implementation (2.3% pre-CP vs. 11.8% post-CP, p = 0.29). Among inpatients we also noted a decrease in broad-spectrum regimens (100% pre-CP vs. 66.7% post-CP, p = 0.02) and the introduction of narrow-spectrum regimens (0% pre-CP vs. 33.3% post-CP, p = 0.02) post-CP. Hospitalized patients received fewer antibiotic courses post-CP (median DOT from 18.5 pre-CP to 10 post-CP, p = 0.004), while there was no statistical difference in length of therapy (median LOT from 11 pre-CP to 10 post-CP, p = 0.06). Days of broad spectrum therapy were notably lower post-CP (median bsDOT from 17 pre-CP to 4.5 post-CP, p <0.0001). No difference in treatment failure was reported before and after CP implementation (16.7% pre-CP vs. 15.4% post-CP, p = 1).

CONCLUSIONS

Introduction of a CP for CAP in a Pediatric Emergency Department led to reduction of broad-spectrum antibiotic prescriptions, of combination therapy and of duration of treatment both for outpatients and inpatients.

Precision antimicrobial therapeutics: the path of least resistance?

The emergence of drug-resistant pathogens has led to a decline in the efficacy of traditional antimicrobial therapy. The rise in resistance has been driven by widespread use, and in some cases misuse, of antibacterial agents in treating a variety of infections. A growing body of research has begun to elucidate the harmful effects of broad-spectrum antibiotic therapy on the beneficial host microbiota. To combat these threats, increasing effort is being directed toward the development of precision antimicrobial therapeutics that target key virulence determinants of specific pathogens while leaving the remainder of the host microbiota undisturbed. This includes the recent development of small molecules termed “mannosides” that specifically target uropathogenic E. coli (UPEC). Mannosides are glycomimetics of the natural mannosylated host receptor for type 1 pili, extracellular appendages that promotes UPEC colonization in the intestine. Type 1 pili are also critical for colonization and infection in the bladder. In both cases, mannosides act as molecular decoys which potently prevent bacteria from binding to host tissues. In mice, oral treatment with mannosides simultaneously clears active bladder infection and removes intestinal UPEC while leaving the gut microbiota structure relatively unchanged. Similar treatment strategies successfully target other pathogens, like adherent-invasive E. coli (AIEC), an organism associated with Crohn’s disease (CD), in mouse models. While not without its challenges, antibiotic-sparing therapeutic approaches hold great promise in a variety of disease systems, including UTI, CD, otitis media (OM), and others. In this perspective we highlight the benefits, progress, and roadblocks to the development of precision antimicrobial therapeutics.

Detection of different classes of carbapenemases: Adaptation and assessment of a phenotypic method applied to Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii, and proposal of a new algorithm

A new phenotypic method for detecting carbapenemases has been adapted (assembling of two MAST® kits, including one that contains faropenem to which a temocillin disk has been added) then assessed using 101 bacterial strains (Enterobacteriaceae with assays on Pseudomonas aeruginosa and Acinetobacter baumannii) including 62 which produce genetically identified carbapenemases. Concerning Carbapenemase-Producing Enterobacteriaceae (CPE), there is 100% sensitivity for Klebsiella pneumoniae carbapenemase (KPC, Ambler class A) and OXA-48 (Ambler class D), and 91% for metallo-beta-lactamase (MBL, Ambler class B), with a 97% sensitivity for all carbapenemases, with a specificity of 100%. The test is also efficient for detecting Pseudomonas aeruginosa carbapenemases (sensitivity between 82 and 100% and 100% specificity). The major innovation is the combined use of faropenem and temocillin for reliable detection (excellent performance with 100% sensitivity and specificity) of OXA-48. This study has led to the development of a new algorithm to detect the different classes of carbapenemases, for first-line diagnosis, by combining this modified MAST® test with immunochromatographic methods and molecular biology techniques.

Active surveillance for carbapenem-resistant Enterobacteriaceae, vancomycin-resistant enterococci and toxigenic Clostridium difficile among patients transferred from long-term care facilities in Korea

A 10-month active surveillance study was conducted to assess carriage of carbapenemase-producing Enterobacteriaceae (CPE), vancomycin-resistant enterococci (VRE) and toxigenic Clostridium difficile colonization among patients transferred to hospital from long-term care facilities (LTCFs). Four (1.4%) patients with carbapenem-resistant Enterobacteriaceae (none of which were CPE), 59 (21%) patients with VRE and 20 (7.1%) patients colonized with toxigenic C. difficile were identified from 282 rectal specimens. There was no outbreak of VRE infection during the study period. The low prevalence of CPE carriage suggests that screening all admissions from LTCFs for CPE would not be cost-effective, and that screening and use of contact precautions for VRE should be reconsidered.

The challenge of converting Gram-positive-only compounds into broad-spectrum antibiotics

Multidrug resistant Gram-negative bacterial infections are on the rise, and there is a lack of new classes of drugs to treat these pathogens. This drug shortage is largely due to the challenge of finding antibiotics that can permeate and persist inside Gram-negative species. Efforts to understand the molecular properties that enable certain compounds to accumulate in Gram-negative bacteria based on retrospective studies of known antibiotics have not been generally actionable in the development of new antibiotics. A recent assessment of the ability of >180 diverse small molecules to accumulate in Escherichia coli led to predictive guidelines for compound accumulation in E. coli. These "eNTRy rules" state that compounds are most likely to accumulate if they contain a nonsterically encumbered ionizable Nitrogen (primary amines are the best), have low Three-dimensionality (globularity ≤ 0.25), and are relatively Rigid (rotatable bonds ≤ 5). In this review, we look back through 50+ years of antibacterial research and 1000s of derivatives and assess this historical data set through the lens of these predictive guidelines. The results are consistent with the eNTRy rules, suggesting that the eNTRy rules may provide an actionable and general roadmap for the conversion of Gram-positive-only compounds into broad-spectrum antibiotics.

High-dose tigecycline for the treatment of nosocomial carbapenem-resistant Klebsiella pneumoniae bloodstream infections: A retrospective cohort study

Carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI) has become increasingly frequent threat recently, especially in the intensive care unit (ICU). High-dose tigecycline (TGC) regimen is proposed due to the limitation of treatment options. We investigated the efficacy and safety of high-dose TGC combination regimens for treating CRKP BSI. Furthermore, the risk factors for mortality were also determined.This was a single center retrospective cohort study conducted from 2014 to 2016. A total of 40 patients with nosocomial CRKP BSI admitted to the ICU were included; they were classified into two groups according to the treatment regimens with high-dose TGC (HD group) or not (non-HD group). In-hospital mortality rates and microbiologic responses from both groups were reviewed and compared. Besides, the survival and non-survival groups were compared to identify the risk factors of mortality.Twenty-three patients constituted the HD group (high-dosage TGC regimen was administered as 200 mg loading dose followed by 100 mg every 12 h) and 17 patients constituted the non-HD group (standard dose TGC therapy as 100 mg loading dose followed by 50 mg every 12 h and other antibiotics). The in-hospital mortality was 52.2% in the HD group and 76.5% in the non-HD group (P = .117). The Kaplan-Meier test showed significantly longer survival times in the HD group (mean: 83 days vs 28 days; P = .027). Microbiological eradication was observed in 13 patients (56.5%) in the HD group and 6 patients (36.3%) in the non-HD group (P = .184). A smaller fraction of patients in the HD group were subjected to vasoactive therapy (52.2% vs 88.2%; P = .016) compared to the non-HD group. There was no significant difference in the manifestation of adverse effects between the two groups. In the multivariate analysis, multiple organ dysfunction syndrome (MODS), vasoactive therapy, and exposure to carbapenems were regarded as the independent predictors of mortality.A therapeutic regimen consisting of a high dose of TGC was associated with significantly longer survival time and numerically lower mortality in CRKP BSI. Adverse events were not increased with the double dose therapy.

Clinical and Molecular Epidemiology of Carbapenem-Resistant Enterobacteriaceae Among Adult Inpatients in Singapore

Background

Since 2010, the incidence of carbapenem-resistant Enterobacteriaceae (CRE) has been increasing in Singapore. We analyzed the clinical and molecular epidemiology of CRE among adult inpatients in Singapore.

Methods

Quarterly incidence of unique subjects (per 100000 patient-days) with positive clinical and surveillance cultures for CRE were estimated based on mandatory data submitted to the National Public Health Laboratory by public hospitals between 2010 and 2015. CRE-positive adult inpatients were prospectively recruited from 6 public sector hospitals between December 2013 and April 2015. Subjects answered a standardized epidemiologic questionnaire and provided samples for this study. Further clinical information was extracted from subjects' electronic medical records. Whole-genome sequencing was performed on study isolates to determine transmission clusters.

Results

Incidence of CRE clinical cultures among adult inpatients plateaued from 2013 (range: 7.73 to 10.32 per 100000 patient-days) following an initial increase between 2010 and end-2012. We prospectively recruited 249 subjects. Their median age was 65 years, 108 (43%) were female, and 161 (64.7%) had carbapenemase-producing Enterobacteriaceae (CPE). On multivariate analysis, prior carbapenem exposure (OR: 3.23; 95% CI: 1.67-6.25) and hematological malignancies (OR: 2.85; 95% CI: 1.10-7.41) were associated with non-carbapenemase-producing CRE (NCPE) (n = 88) compared with CPE (n = 161) subjects. Among 430 CRE isolates from the 249 subjects, 307(71.3%) were CPE, of which 154(50.2%) were blaKPC-positive, 97(31.6%) blaNDM-positive, and 42 (13.7%) blaOXA-positive. Klebsiella pneumoniae (n = 180, 41.9%), Escherichia coli (n = 129, 30.0%) and Enterobacter cloacae (n = 62, 14.4%) were the main Enterobacteriaceae species. WGS (n = 206) revealed diverse bacterial strain type (STs). The predominant blaKPC-positive plasmid was pHS102707 (n = 62, 55.4%) and the predominant blaNDM-positive plasmid was pNDM-ECS01 (n = 46, 48.9%). Five transmission clusters involving 13 subjects were detected.

Conclusions

Clinical CRE trend among adult inpatients showed stabilization following a rapid rise since introduction in 2010 potentially due to infection prevention measures and antimicrobial stewardship. More work is needed on understanding CPE transmission dynamics.

Evaluation of Sensititre Broth Microdilution Plate for determining the susceptibility of carbapenem-resistant Klebsiella pneumoniae to polymyxins

Colistin and polymyxin B MICs were determined for 106 carbapenem-resistant Klebsiella pneumoniae (CR-Kp) isolates using Sensititre Research Use Only GNX2F plates (Thermo Fisher) and compared to CLSI broth macrodilution (BMD) as the reference method. For colistin, EUCAST breakpoints were applied and testing of isolates with very major (VM) errors was repeated in duplicate by both methods to determine a majority result. Essential agreement (MIC ± one dilution) of GNX2F with the reference method was 97.1% for polymyxin B and 92.5% for colistin (7 VM errors, 22.6%). After discrepancy testing, there were 28 colistin resistant isolates by BMD and essential agreement was 94.3% with 4 VM errors (14.3%). Colistin and polymyxin B GNX2F results showed acceptable essential agreement with BMD for MICS without interpretation. Colistin VM errors with EUCAST breakpoints were due to MIC variability in the 2 to 4 μg/mL range that could be addressed by establishing an intermediate category.

The Expanding Role of Antimicrobial Stewardship Programs in Hospitals in the United States: Lessons Learned from a Multisite Qualitative Study

BACKGROUND

Misuse of antibiotics can lead to the development of antibiotic resistance, which adversely affects morbidity, mortality, length of stay, and cost. To combat the threat of antimicrobial resistance, The Joint Commission and the Centers for Medicare & Medicaid Services have initiated or proposed requirements for hospitals to have antimicrobial stewardship programs (ASPs), but implementation remains challenging. A key-informant interview study was conducted to describe the characteristics and innovative strategies of leading ASPs.

METHODS

Semistructured interviews were conducted with 12 program leaders at four ASPs in the United States, chosen by purposive sampling on the basis of national reputation, scholarship, and geography. Questions focused on ASP implementation, program structure, strengths, weaknesses, lessons learned, and future directions. Content analysis was used to identify dominant themes.

RESULTS

Three major themes were identified. The first was evolution of ASPs from a top-down structure to a more diffuse approach involving unit-based pharmacists, multidisciplinary staff, and shared responsibility for antimicrobial prescribing under the ASPs' leadership. The second theme was integration of information technology (IT) systems, which enabled real-time interventions to optimize antimicrobial therapy and patient management. The third was barriers to technology integration, including limited resources for data analysis and poor interoperability between software systems.

CONCLUSION

The study provides valuable insights on program implementation at a sample of leading ASPs across the United States. These ASPs used expansion of personnel to amplify the ASP's impact and integrated IT resources into daily work flow to improve efficiency. These findings can be used to guide implementation at other hospitals and aid in future policy development.