Carbapenem-resistant Enterobacteriaceae: Prevalence and Risk Factors in a Single Community-Based Hospital in Korea

Antimicrobial Use and Carbapenem-Resistant Enterobacterales in Korea: A Nationwide Case-Control Study With Propensity Score Matching

BACKGROUND

Nationwide research on the association between carbapenem-resistant Enterobacterales (CREs) and antibiotic use is limited.

METHODS

This nested case-control study analyzed Korean National Health Insurance claims data from April 2017 to April 2019. Based on the occurrence of CRE, hospitalized patients aged ≥ 18 years were classified into CRE (cases) and control groups. Propensity scores based on age, sex, modified Charlson comorbidity score, insurance type, long-term care facility, intensive care unit stay, and acquisition of vancomycin-resistant Enterococci were used to match the case and control groups (1:3).

RESULTS

After matching, the study included 6,476 participants (1,619 cases and 4,857 controls). Multivariable logistic regression analysis revealed that the utilization of broad-spectrum antibiotics, such as piperacillin/tazobactam (adjusted odds ratio [aOR], 2.178; 95% confidence interval [CI], 1.829-2.594), third/fourth generation cephalosporins (aOR, 1.764; 95% CI, 1.514-2.056), and carbapenems (aOR, 1.775; 95% CI, 1.454-2.165), as well as the presence of comorbidities (diabetes [aOR, 1.237; 95% CI, 1.061-1.443], hemiplegia or paraplegia [aOR, 1.370; 95% CI, 1.119-1.679], kidney disease [aOR, 1.312; 95% CI, 1.105-1.559], and liver disease [aOR, 1.431; 95% CI, 1.073-1.908]), were significantly associated with the development of CRE. Additionally, the CRE group had higher mortality (8.33 vs. 3.32 incidence rate per 100 person-months, P < 0.001) and a total cost of healthcare utilization per person-month (15,325,491 ± 23,587,378 vs. 5,263,373 ± 14,070,118 KRW, P < 0.001) than the control group.

CONCLUSION

The utilization of broad-spectrum antibiotics and the presence of comorbidities are associated with increasing development of CRE. This study emphasizes the importance of antimicrobial stewardship in reducing broad-spectrum antibiotic use and CRE disease burden in Korea.

Epidemiology of Carbapenem-Resistant Enterobacteriaceae Bacteremia in Gyeonggi Province, Republic of Korea, between 2018 and 2021

The incidence of carbapenem-resistant Enterobacteriaceae (CRE) has been increasing since 2008, with Gyeonggi Province in South Korea being particularly vulnerable due to its large number of healthcare facilities. This study examines the trends of CRE occurrence in Gyeonggi Province over the past four years and the epidemiological characteristics of the infected patients. Patients with positive CRE blood cultures admitted to healthcare facilities in Gyeonggi Province from January 2018 to December 2021 were evaluated in this study. Risk factors for CRE-related death were analyzed using data from patients who died within 30 days of the last blood sampling. Older adults aged 70 years and above constituted the majority of patients with CRE bacteremia. Antibiotic use did not significantly affect mortality risk. Non-survivors were more common in tertiary hospitals and intensive care units and included patients with hypertension, malignant tumors, and multiple underlying diseases. Klebsiella pneumoniae was the most common CRE strain, with Klebsiella pneumoniae carbapenemase being the predominant carbapenemase. Our study suggests the endemicity of CRE in Gyeonggi Province and highlights the increasing isolation of CRE strains in South Korean long-term care hospitals within the province. Further, infection control measures and government support specific to each healthcare facility type are crucial.

Klebsiella pneumoniae carbapenamases in Escherichia coli isolated from humans and livestock in rural south-western Uganda

BACKGROUND

The accumulation of resistance genes in Escherichia coli (E. coli) strains imposes limitations in the therapeutic options available for the treatment of infections caused by E.coli. Production of Klebsiella pneumoniae carbapenemase (KPC) by E. coli renders it resistant to broad-spectrum β-lactam antibiotics. Globally there is existing evidence of spread of carbapenem-resistant E. coli in both humans and livestock driven by acquisition of the several other carbapenemase genes. Overall, there is little information regarding the extent of KPC gene distribution in E. coli. We set out to determine the prevalence, and evaluate the phenotypic and genotypic patterns of KPC in E. coli isolated from humans and their livestock in rural south western Uganda.

METHODS

A laboratory-based, descriptive cross-sectional study was conducted involving 96 human and 96 livestock isolates collected from agro-pastoralist communities in Mbarara district in south western Uganda. Phenotypic and molecular methods (PCR) were used for presence and identification of KPC genes in the E. coli isolates. A chi-square test of independence was used to evaluate the differences in resistant patterns between carbapenems and isolates.

RESULTS

The overall prevalence of carbapenem resistance by disk diffusion susceptibility testing (DST) for both humans and livestock isolates were 41.7% (80/192). DST-based resistance was identical in both human and livestock isolates (41.7%). The prevalence of carbapenem resistance based on Modified Hodge Test (MHT) was 5% (2/40) and 10% (4/40) for humans and livestock isolates respectively. Both human and livestock isolates, 48.7% (95/192) had the KPC gene, higher than phenotypic expression; 41.7% (80/192). blaKPC gene prevalence was overall similar in human isolates (51%; 49/96) vs livestock isolates (47.9%; 46/96). Approximately, 19% (15/80) of the isolates were phenotypically resistant to carbapenems and over 70% (79/112) of the phenotypically sensitive strains harbored the blaKPC gene.

CONCLUSION

Our results suggest that both human and livestock isolates of E. coli in our setting carry the blaKPC gene with a high percentage of strains not actively expressing the blaKPC gene. The finding of fewer isolates carrying the KPC gene than those phenotypically resistant to carbapenems suggests that other mechanisms are playing a role in this phenomenon, calling for further researcher into this phenomenon.

Prevalence of carbapenemase-producing Enterobacteriaceae from human clinical samples in Ethiopia: a systematic review and meta-analysis

INTRODUCTION

Carbapenemase-producing Enterobacteriaceae are by far the most public health and urgent clinical problems with antibiotic resistance. They cause longer hospital stays, more expensive medical care, and greater mortality rates. This systematic review and meta-analysis aimed to indicate the prevalence of carbapenemase-producing Enterobacteriaceae in Ethiopia.

METHODS

This systematic review and meta-analysis was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Electronic databases like PubMed, Google Scholar, CINAHL, Wiley Online Library, African Journal Online, Science Direct, Embase, ResearchGate, Scopus, and the Web of Sciences were used to find relevant articles. In addition, the Joanna Briggs Institute quality appraisal tool was used to assess the quality of the included studies. Stata 14.0 was used for statistical analysis. Heterogeneity was assessed by using Cochran's Q test and I² statistics. In addition, publication bias was assessed using a funnel plot and Egger's test. A random effect model was used to estimate the pooled prevalence. Sub-group and sensitivity analysis were also done.

RESULTS

The overall pooled prevalence of carbapenemase-producing Enterobacteriaceae in Ethiopia was 5.44% (95% CI 3.97, 6.92). The prevalence was highest [6.45% (95% CI 3.88, 9.02)] in Central Ethiopia, and lowest [(1.65% (95% CI 0.66, 2.65)] in the Southern Nations and Nationalities People Region. In terms of publication year, 2017-2018 had the highest pooled prevalence [17.44 (95% CI 8.56, 26.32)] and 2015-2016 had the lowest [2.24% (95% CI 0.87, 3.60)].

CONCLUSION

This systematic review and meta-analysis showed a high prevalence of carbapenemase-producing Enterobacteriaceae. So, to alter the routine use of antibiotics, regular drug susceptibility testing, strengthening the infection prevention approach, and additional national surveillance on the profile of carbapenem resistance and their determining genes among Enterobacteriaceae clinical isolates are required.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (2022: CRD42022340181).

A Visualized Mortality Prediction Score Model in Hematological Malignancies Patients with Carbapenem-Resistant Organisms Bloodstream Infection

Background

Bloodstream infection (BSI) due to carbapenem-resistant organisms (CROs) has emerged as a worldwide problem associated with high mortality. This study aimed to evaluate the risk factors associated with mortality in HM patients with CROs BSI and to establish a scoring model for early mortality prediction.

Methods

We conducted a retrospective cohort study at our hematological department from January 2018 to December 2021, including all HM patients with CROs BSI. The outcome measured was death within 30-day of BSI onset. Survivor and non-survivor subgroups were compared to identify predictors of mortality. Univariate and multivariate Cox regression analyses were used to identify prognostic risk factors and develop a nomogram.

Results

In total, 150 HM patients were included in the study showing an overall 30-day mortality rate of 56%. Klebsiella pneumonia was the dominant episode. Cox regression analysis showed that pre-infection length of stay was >14 days (score 41), Pitt score >4 (score 100), mucositis (score 41), CAR (The ratio of C-reactive protein to albumin) >8.8 (score 57), early definitive therapy (score 44), and long-duration (score 78) were positive independent risk predictors associated with 30-day mortality, all of which were selected into the nomogram. Furthermore, all patients were divided into the high-risk group (≥160 points) or the low-risk group based on the prediction score model. The mortality of the high-risk group was 8 times more than the low-risk group. Kaplan-Meier analysis showed that empirical polymyxin B therapy was associated with a lower 30-day mortality rate, which was identified as a good prognostic factor in the high-risk group. In comparison, empirical carbapenems and tigecycline were poor prognostic factors in a low-risk group.

Conclusion

Our score model can accurately predict 30-day mortality in HM patients with CROs BSI. Early administration of CROs-targeted therapy in the high-risk group is strongly recommended to decrease mortality.

Emergence and clonal spread of KPC-2-producing clinical Klebsiella aerogenes isolates in a hospital from northwest Argentina

Introduction. Klebsiella aerogenes is a nosocomial pathogen associated with drug resistance and healthcare-associated infections.Gap Statement. K. aerogenes is associated with hospital-acquired infections with the ability to acquire mechanisms of resistance to reserve antimicrobials; its clinical behaviour has been poorly documented.Objective. We proposed to investigate an outbreak of carbapenem-resistant K. aerogenes in a hospital that persisted for 4 months.Methods. The primary aim was to evaluate the molecular characteristics and the clonal relationships among the isolates. We characterized isolates by polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE). The information was integrated with clinical and epidemiological data.Results. Fourteen strains were disseminated in an intensive care unit and different wards at the hospital. The overall mortality was 42.8 %, and mortality attributed to infection was 21.4 %; strains showed high rates of resistance to most of the antimicrobials tested and carried bla _KPC-2, bla _SHV-2 and bla _CTXM-15 genes. PFGE analysis indicated 2 PFGE groups; 12/14 isolates were associated with subgroup A and were likely to be primarily responsible for the first isolation and subsequent dissemination. The outbreak characteristics data showed prolonged hospitalization and previous use of antibiotics as potential risk factors.Conclusion. We consider that it is essential to perform phenotypic and genotypic identification of early genetic resistance mechanisms in K. aerogenes isolates, not only from infection sites but also from colonization, to prevent the spread of these multidrug-resistant (MDR) isolates.

Effect of restricting piperacillin/tazobactam prescription on rates of antimicrobial resistance in gram-negative bacteria and antibiotic consumption

The increasing resistance of gram-negative bacteria is a serious global public health concern. One way to prevent increasing antibiotic resistance is by implementing the antibiotic stewardship program. This study aimed to assess the changes in the consumption of antimicrobials and antimicrobial resistance rates after implementing piperacillin/tazobactam restriction. This study was conducted at Kandong Sacred Heart Hospital. We retrospectively collected and analysed data between October 2018 and May 2021 to evaluate antibiotic consumption and resistance patterns after restricting piperacillin/tazobactam. This study included two periods, a 16-month pre-restriction period and a 16-month post-restriction period. During the study period, there was a significant decrease in the consumption of piperacillin/tazobactam after implementing the restriction policy (127.82 ± 9.39 to 104.82 ± 15.66 defined daily doses/1000 patient days, p < 0.001). A significant decrease in the resistance rate of Acinetobacter spp. was observed for cefepime (p = 0.001), ceftazidime (p = 0.004), levofloxacin (p = 0.021), meropenem (p = 0.002) and piperacillin (p = 0.028). The introduction of piperacillin/tazobactam restriction reduced their use and positively impacted the resistance rates of Acinetobacter spp., carbapenem-resistant Pseudomonas spp. and carbapenem-resistant Enterobacteriaceae which are major threats to nosocomial infections.

Korean Guidelines for Use of Antibiotics for Intra-abdominal Infections in Adults

The guidelines are intended to provide practical information for the correct use of antibiotics for intra-abdominal infections in Korea. With the aim of realizing evidence-based treatment, these guidelines for the use of antibiotics were written to help clinicians find answers to key clinical questions that arise in the course of patient care, using the latest research results based on systematic literature review. The guidelines were prepared in consideration of the data on the causative pathogens of intra-abdominal infections in Korea, the antibiotic susceptibility of the causative pathogens, and the antibiotics available in Korea.

Impact of carbapenem resistance on mortality in patients infected with Enterobacteriaceae: a systematic review and meta-analysis

OBJECTIVES

To provide a comprehensive assessment of the impact of carbapenem resistance on mortality among patients infected with Enterobacteriaceae and to explore the source of heterogeneity across studies.

DESIGN

This systematic review was conducted following the guidelines of Cochrane Guidance and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

DATA SOURCES

We conducted a systematic literature search of the PubMed, Embase, Web of Science and Cochrane Library databases to identify relevant studies published between 1 January 1994 and 30 August 2020.

ELIGIBILITY CRITERIA

We included primary observational studies published in English that reported the mortality outcomes for hospitalised patients with confirmed infections due to carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-susceptible Enterobacteriaceae (CSE). Studies with no comparison group or with a comparison group of patients infected with unconfirmed CSE were excluded.

DATA EXTRACTION AND SYNTHESIS

Data extraction and assessment of risk bias were conducted independently by two reviewers. The pooled relative risk and risk difference were calculated as effect measures with 95% CIs using a random effects model. The heterogeneity across studies was assessed by Q-statistic and I² measures.

RESULTS

Of 10 304 studies initially identified, 50 studies were included in the meta-analyses. The results of the meta-analyses showed that carbapenem resistance has a significant positive effect on the probability of death for patients infected with Enterobacteriaceae for any type of mortality outcome. The results of the stratified analysis and meta-regression suggested that the effect of carbapenem resistance on the risk of death varied by infection type, sample size and year of publication.

CONCLUSIONS

Our results suggested that patients with CRE infection still face a greater risk of death than patients with CSE infection do, and an urgent need to develop new antibiotics and appropriate treatments to reduce the risk of death.

PROSPERO REGISTRATION NUMBER

CRD42020176808.

Development of a Candidate Multi-Epitope Subunit Vaccine against Klebsiella aerogenes: Subtractive Proteomics and Immuno-Informatics Approach

Klebsiella aerogenes is a Gram-negative bacterium which has gained considerable importance in recent years. It is involved in 10% of nosocomial and community-acquired urinary tract infections and 12% of hospital-acquired pneumonia. This organism has an intrinsic ability to produce inducible chromosomal AmpC beta-lactamases, which confer high resistance. The drug resistance in K. aerogenes has been reported in China, Israel, Poland, Italy and the United States, with a high mortality rate (~50%). This study aims to combine immunological approaches with molecular docking approaches for three highly antigenic proteins to design vaccines against K. aerogenes. The synthesis of the B-cell, T-cell (CTL and HTL) and IFN-γ epitopes of the targeted proteins was performed and most conserved epitopes were chosen for future research studies. The vaccine was predicted by connecting the respective epitopes, i.e., B cells, CTL and HTL with KK, AAY and GPGPG linkers and all these were connected with N-terminal adjuvants with EAAAK linker. The humoral response of the constructed vaccine was measured through IFN-γ and B-cell epitopes. Before being used as vaccine candidate, all identified B-cell, HTL and CTL epitopes were tested for antigenicity, allergenicity and toxicity to check the safety profiles of our vaccine. To find out the compatibility of constructed vaccine with receptors, MHC-I, followed by MHC-II and TLR4 receptors, was docked with the vaccine. Lastly, in order to precisely certify the proper expression and integrity of our construct, in silico cloning was carried out. Further studies are needed to confirm the safety features and immunogenicity of the vaccine.

Antibiotic Resistance Genes Among Carbapenem-resistant Enterobacterales (CRE) Isolates of Prapokklao Hospital, Chanthaburi Province, Thailand

Background

The global spread of carbapenem-resistant Enterobacterales (CRE) inflicts a severe threat to human health. The CRE infections have resulted in an increased mortality rate in hospitals and other health-care settings worldwide. In this study, the antibiotic-resistance pattern and prevalence of carbapenemase-encoding genes among CRE isolated from patients of one hospital in Thailand were investigated.

Methods

By using conventional biochemical tests, we identified and isolated all species of Enterobacterales from the clinical samples kept at Prapokklao Hospital, Chanthaburi, Thailand, which were collected during 2016–2017. Multidrug-resistant (MDR) bacteria were determined by disc diffusion method and minimum inhibitory concentration (MIC) test strips. Carbapenemase genes were detected by PCR and confirmed by Sanger sequencing.

Results

Klebsiella pneumoniae complex, Escherichia coli, and Enterobacter spp. were isolated from the specimens. Of 9,564 isolated Enterobacterales, 282 were multidrug-resistance (MDR). The MIC test strips revealed that the MDR CRE were resistant to ertapenem (92.9%) and meropenem (81.3%). All these isolates carried carbapenemase-coding genes, including bla_NDM (90%) and bla_IMP (71%), the two most commonly found genes among CRE strains. There were 39.2% of the isolates that carried a combination of bla_NDM-bla_IMP and 22.6% carried combined bla_NDM-bla_IMP-bla_OXA-48-like genes.

Conclusion

This study demonstrates a significantly high prevalence of CRE isolates with the MDR phenotypes. A minority of the isolates carried a single carbapenem-resistant gene, while the majority harbored multiple genes in combination. Regular monitoring of MDR CRE and characterization of their drug resistance are important for guiding treatment, intervention and control of the CRE spread and outbreak in a health-care setting.

Identification and infection control of carbapenem-resistant Enterobacterales in intensive care units

Infections with multidrug-resistant organisms among patients in intensive care units (ICUs) are associated with high mortality. Among multidrug-resistant organisms, carbapenem-resistant Enterobacterales (CRE) harbor important pathogens for healthcare-associated infections, including pneumonia, bacteremia, and urinary tract infections. Risk factors for CRE colonization include underlying comorbid conditions, prior antibiotics exposure, prior use of healthcare facilities, device use, and longer ICU stay. The mortality rate due to invasive CRE infection is 22%–49%, and CRE colonization is associated with an approximately 10-fold increased risk of CRE infection. Infection control measures include hand hygiene, contact precautions, minimizing the use of devices, and environmental control. Additionally, implementing active surveillance of CRE carriage should be considered in ICU settings.

Incidence and risk factors of carbapenem-resistant Enterobacteriaceae infection in intensive care units: a matched case-control study

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) infection is associated with intensive care admissions, morbidity, and mortality. Our study aimed to determine the incidence, risk factors, and patient outcomes of CRE in the ICU units.

METHODS

This was a retrospective matched case-control study of patients admitted to ICUs. Patients who have positive cultures of CRE and carbapenem-susceptible Enterobacteriaceae (CSE) were included in the study. Patients were randomly selected from a pool of CSE subjects in a ratio of 1:1 of CRE to CSE as control patients.

RESULTS

The infection rate with CRE among all patients admitted to ICUs was 7.6% and the incidence of CRE infection was 5.6 per 1,000 person-day. The risk factors independently associated with CRE infection were: Higher Sequential Organ Failure Assessment (SOFA) and Nutrition Risk in Critically ill (NUTRIC) scores, prolonged ICU length of stay (LOS), previous surgery, dialysis and mechanical ventilation during ICU stay, and previous use of aminoglycoside and carbapenems.

CONCLUSION

In this retrospective study, the incidence of CRE infection was relatively elevated in patients admitted to ICU. Patients with high SOFA and NUTRIC scores, prolonged ICU LOS, previous surgery, dialysis and mechanical ventilation, and prior aminoglycosides and carbapenems use, may have an increased risk of CRE infection.

Positivity of Carbapenemase-producing Enterobacteriaceae in Patients Following Exposure within Long-term Care Facilities in Seoul, Korea

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE) are emerging as a worldwide threat. Long-term care facilities (LTCFs) are considered a reservoir for CPE and play a central role in transmission to acute care hospitals. We investigated the CPE positivity in patients exposed to CPE in LTCFs. Furthermore, we analyzed the CPE positivity rates in the environment exposed to CPE.

METHODS

We collected rectal swab specimens from patients residing in LTCFs who were exposed to CPE. Environmental sampling was performed by infection control practitioners from sites classified as patient private space, common space in the patient room, common space other than patient rooms, and nursing station. Each sample was cultured on a Chrom Klebsiella pneumoniae carbapenemase (KPC) agar for CPE screening. The positive isolates were subjected to a polymerase chain reaction to identify the presence of bla_KPC, bla_VIM, bla_IMP, bla_OXA-48, and bla_NDM and determine CPE genotype.

RESULTS

From 65 index cases, a total of 24 hospitals and 481 patients were enrolled; 414 patients who had resided in the same patient room as a patient with confirmed CPE and 67 patients who were newly admitted to that patient room. A total of 117 (24.3%) patients were positive for CPE among which 93 (22.5%, 93/414) were already admitted patients and 24 (35.8%, 24/67) were newly admitted patients. A total of 163 CPEs were detected and K. pneumoniae (n = 104, 63.8%) was the most common bacteria followed by Escherichia coli (n = 43, 26.4%) and Citrobacter koseri (n = 11, 6.7%). Environmental sampling was performed in 24 hospitals and 604 sites. A total of 12 sites (2.0%) were positive for CPE and sink in the nursing station (n = 6, 4.2%) was the most contaminated space.

CONCLUSION

CPE colonization rates in patients exposed to CPE in LTCFs were higher than those found in acute care hospitals. Proper infection control measures for detecting and reducing CPE colonization in patients residing in LTCFs are required. Newly admitted patients could also be carriers; therefore, infection control for newly admitted patients also needs to be thorough.

Lymphocyte subset counts as diagnostic and prognostic markers for carbapenem-resistant Enterobacteriaceae (CRE) infection in critically ill patients

OBJECTIVES

This study investigated the use of lymphocyte subset counts as diagnostic and prognostic markers for carbapenem-resistant Enterobacteriaceae (CRE) infection.

METHODS

We assessed the lymphocyte subset populations and other clinical parameters of septic patients upon intensive care unit (ICU) admission, and evaluated their potential impact on CRE infection diagnosis and outcome.

RESULTS

Among 373 septic patients, 51 were diagnosed with CRE infection. The 28-day mortality was significantly higher in CRE than non-CRE patients (35.3% vs 14.9%). The T lymphocyte count and CD4⁺CD28⁺ T cell count were both independent risk factors for CRE infection, with the latter had the best diagnostic ability (AUC: 0.908; p < 0.0001). Lower CD4⁺CD28⁺ T cell counts were associated with higher likelihoods of CRE infection. The CRE incidence and 28-day mortality of CRE-infected patients could be predicted using cutoff values of 242 (sensitivity: 83.9%; specificity: 87.5%) and 58.5 (sensitivity: 100%; specificity: 61.1%) CD4⁺CD28⁺ T cells/μl at ICU admission, respectively.

CONCLUSIONS

Septic patients with CRE infection had higher 28-day mortality. Given that the CD4⁺CD28⁺ T cell count was significantly lower in CRE than non-CRE septic patients and a lower cell count was significantly associated with higher 28-day mortality, CD4⁺CD28⁺ T cell counts may be useful markers for early diagnosis of CRE infection and outcome prediction.

Epidemiology and risk factors for carbapenem-resistant Enterobacteriaceae colonisation and infections: case-controlled study from an academic medical center in a southern area of China

OBJECTIVE

While the emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE) and related infections pose serious threats to global public health, the epidemiology and associated risk factors remain poorly understood and vary by geography.

METHODS

In a case-controlled retrospective study, we examined the prevalence, patient background and risk factors for CRE colonisation and infections, and all patient-derived CRE from January 2015 to January 2017. Isolated carbapenem-susceptible Enterobacteriaceae (CSE) from 2875 enrolled patients were randomly selected during the study.

RESULTS

CRE colonisation and infections detection rates were 47/2875 (1.6%). Respiratory tract specimens were most frequently seen in 20/47 (42.6%) cases. Klebsiella pneumoniae was the main isolate in 35/47 (74.5%) CRE. As for carbapenemase, KPC-2-producing bacteria was most frequently detected in 38/47 (80.9%) Enterobacteriaceae. No underlying conditions (P = 0.004), pulmonary diseases (P = 0.018) and no antibiotics used prior to culture within 30 days (P < 0.001) were statistically significant between the CRE and CSE groups.

CONCLUSION

Klebsiellapneumoniae was the main isolate of CRE. The blaKPC-2 was the predominant CRE gene. Underlying conditions especially pulmonary diseases and antibiotics used prior to culture within 30 days represented key risk factors for acquisition of CRE.

MCR1 and KPC2 Co-producing Klebsiella pneumoniae Bacteremia: First Case in Korea

Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP) has been disseminating nationwide due to clonal spread and is taking a serious action at the national level in Korea. The mobilized colistin resistance (MCR1) gene confers plasmid-mediated resistance to colistin and is known to be capable of horizontal transfer between different strains of a bacterial species. We have experienced a fatal case of the patient who developed MCR1-possessing, ST307/Tn4401a[blaKPC2] K. pneumonia bacteremia in the community of non-capital region after being diagnosed as pancreatic cancer with multiple liver metastases and treated in the capital region. The ST307/Tn4401a[blaKPC2] K. pneumonia was the most commonly disseminated clone in Korea. Our strain is the first MCR1 and KPC2 co-producing K. pneumonia in Korea and our case is the critical example that the multi-drug resistant clone can cause inter-regional spread and the community-onset fatal infections. Fortunately, our patient was admitted to the intensive care unit on the day of visit, and the contact precaution was well maintained throughout and KPC-KP was not spread to other patients. The high risk patients for KPC-KP need to be screened actively, detected rapidly and preemptively isolated to prevent outbreak of KPC-KP. Inter-facility communications are essential and the nationwide epidemiologic data of KPC-KP should be analyzed and reported regularly to prevent spread of KPC-KP. The prompt identification of species and antimicrobial susceptibilities for successful treatment against KPC-KP should be emphasized as well.

Association between carbapenem-resistant Enterobacteriaceae and death: A systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) has emerged in health care facilities around the world. Several studies demonstrated data regarding clinical outcomes for CRE infections including death. This systematic review and meta-analysis summarized literature discussing association between CRE and mortality.

METHODS

A systematic literature review was performed by searching EMBASE, International Pharmaceutical Abstract databases, PubMed, and Scopus and to identify studies that assessed the association between CRE and death published from April 2012 to October 2017. A meta-analysis was performed using a random effect model. Heterogeneity was assessed using the I²-statistic.

RESULTS

Twenty-one studies were included in this meta-analysis. The underlying populations were moderately heterogeneous (I² = 60%; P = .01). Pooled risk estimates from 9 studies revealed a significant association between CRE and death (pooled-adjusted odds ratio: 2.85; 95% confidence interval: 1.88, 4.30). The unadjusted variable pooled from 18 studies demonstrated a significant association between CRE and death (pooled-unadjusted odds ratio: 3.73; 95% confidence interval: 2.02, 6.88).

DISCUSSION

The finding that CRE infection was positively associated with death agreed with the previous meta-analysis of studies published before April 2012.

CONCLUSIONS

This meta-analysis found that CRE was associated with increased risk of death. Our analysis implies a need for strict infection control measures.

Epidemiology of resistance and phenotypic characterization of carbapenem resistance mechanisms in Klebsiella pneumoniae isolates at Sahloul University Hospital-Sousse, Tunisia

Objective

To assess the prevalence of ESBL producing and carbapenem resistant Klebsiella pneumoniae isolated from in-come and out-come patients at Sahloul-university hospital.

Methods

A retrospective study over a 3 years period (January 2012 and December 2014) focused on 2160 strains of Klebsiella pneumoniae. Statistical analysis was carried out using SPSS program. ESBL detection was performed using a double disc diffusion method and carbapenemase detection was realized by Rosco-Disk kit.

Results

A total of 2160 Klebsiella pneumoniae strains were isolated during the period of the study, 26.2% (n=566) were ESBL-producers and 15.8% (n=342) showed resistance to carbapenem. The wards most affected by these strains were basically urology and intensive care units. Eighty four percent of studied strains (203/241) were resistant to temocillin, which correlate with the production of a class D (OXA-48-like) carbapenemase and 7% (17/241) showed sensitivity to EDTA and dipicolinic acid, which indicate the production of metallo-enzyme. The rate of resistance to colistin remains low.

Conclusion

Resistance of Enterobacteriaceae, including K. pneumoniae, to third generation cephalosporins (3rd GC) and carbapenem through the mechanism of ESBL and carbapenemases production is becoming increasingly worrying. This suggests a more rational use of antibiotics, as well as the rigorous application of hygiene measurement.

Next-Generation-Sequencing-Based Hospital Outbreak Investigation Yields Insight into Klebsiella aerogenes Population Structure and Determinants of Carbapenem Resistance and Pathogenicity

Klebsiella aerogenes is a nosocomial pathogen associated with drug resistance and outbreaks in intensive care units. In a 5-month period in 2017, we experienced an increased incidence of cultures for carbapenem-resistant K. aerogenes (CR-KA) from an adult cardiothoracic intensive care unit (CICU) involving 15 patients. Phylogenomic analysis following whole-genome sequencing (WGS) identified the outbreak CR-KA isolates to group together as a tight monoclonal cluster (with no more than six single nucleotide polymorphisms [SNPs]), suggestive of a protracted intraward transmission event. No clonal relationships were identified between the CICU CR-KA strains and additional hospital CR-KA patient isolates from different wards and/or previous years. Carbapenemase-encoding genes and drug-resistant plasmids were absent in the outbreak strains, and carbapenem resistance was attributed to mutations impacting AmpD activity and membrane permeability. The CICU outbreak strains harbored an integrative conjugative element (ICE) which has been associated with pathogenic Klebsiella pneumoniae lineages (ICEKp10). Comparative genomics with global K. aerogenes genomes showed our outbreak strains to group closely with global sequence type 4 (ST4) strains, which, along with ST93, likely represent dominant K. aerogenes lineages associated with human infections. For poorly characterized pathogens, scaling analyses to include sequenced genomes from public databases offer the opportunity to identify emerging trends and dominant clones associated with specific attributes, syndromes, and geographical locations.

Prevalence and Risk Factors of Carbapenem-resistant Enterobacteriaceae Acquisition in an Emergency Intensive Care Unit in a Tertiary Hospital in Korea: a Case-Control Study

BACKGROUND

Infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are associated with high mortality rates and their treatment is difficult because treatment is limited to certain antibiotics, such as colistin and tigecycline. We aimed to perform active surveillance culture of CRE (ASC-CRE) to monitor the prevalence of CRE acquisition during intensive care unit (ICU) care and to examine the potential risk factors associated with CRE acquisition.

METHODS

We conducted ASC-CRE on patients who were admitted to the ICU in the emergency room at a tertiary hospital. Rectal swabs were analyzed using methods established by the Centers for Disease Control and Prevention. To detect carbapenemase-producing CRE, a polymerase chain reaction assay to detect five carbapenemase genes (bla_NDM, bla_KPC, bla_VIM, bla_IMP-1, and bla_OXA-48) was performed.

RESULTS

There were 22 CRE acquisition in 21 patients (2.6%, 21/810) and the incidence of CRE acquisition was 4.3/1,000 person-days, respectively. The most common species detected was Klebsiella pneumoniae (72.7%, 16/22), and 9 carbapenemase-producing CREs (7 bla_KPC and 2 bla_NDM) were detected. Independent risk factors associated with CRE acquisition were men gender (adjusted odds ratio [aOR], 5.3; 95% confidence interval [CI], 1.3-21.3), history of admission within one year (aOR, 3.9; 95% CI, 1.2-12.1), co-colonization with multidrug-resistant Acinetobacter baumannii (aOR, 15.6; 95% CI, 3.6-67.8) and extended-spectrum β-lactamases-producing bacteria (aOR, 4.7; 95% CI, 1.5-14.6), and exposure to glycopeptide antibiotics (aOR, 3.6; 95% CI, 1.3-9.9).

CONCLUSION

The identification of patients with risk factors for CRE acquisition and early detection of CRE acquisition using ASC-CRE may be useful for CRE control.

The epidemiology and risk factor of carbapenem-resistant enterobacteriaceae colonization and infections: Case control study in a single institute in Japan

INTRODUCTION

While the emergence and spread of carbapenem-resistant enterobacteriaceae (CRE) carriage and infections are serious threats to public health worldwide, its prevalence and epidemiology are still unknown.

METHODS AND PATIENTS

For the purpose of examining the prevalence, patients' background and risk factors for CRE carriage and infections, we conducted this case-control study. We retrospectively reviewed all patients isolating CRE at Aichi Medical University hospital from January 2010 until March 2017. The patients isolated with carbapenem-susceptible enterobacteriaceae (CSE) were randomly selected during the study period.

RESULTS

A total of 26 patients, isolating 28 CRE infections were enrolled in this study. The detection rate of CRE carriage and infection was 0.22% (28/12,600). Compared to the CSE group, the CRE group had poorer PS and higher CCI scores. The CRE group tended to stay longer in hospital (121 v.s. 63 days, p = 0.052) and admission fee was much more expensive than CSE group (220,710 v.s. 69,904 JPY, p < 0.001). PS 2-4 (ECOG) and CCI≧3 (p = 0.002), prior hospitalization within 90 days (p = 0.006) and prior antibiotics use within 90 days (p = 0.005) were risk factors for acquisition of CRE by univariate analysis. The combination of PS 2-4 and CCI≧3 was an independent risk factor for CRE carriage and infection by multivariate logistic regression analysis.

CONCLUSION

The combination of PS 2-4 (ECOG) and CCI score≧3 was an independent risk factor of CRE carriage and infections. The CRE group tended to stay longer in hospital, and the medical expense was much more expensive than those in the CSE group.

Epidemiology and treatment of antimicrobialresistant gram-negative bacteria in Korea

Antimicrobial resistance is becoming one of the greatest challenges to public health worldwide. Infections by antimicrobial-resistant organisms could result in the failure of treatment, increased medical costs, prolonged hospital stays, and an increased socioeconomic burden. Antimicrobial usage in Korea remains heavy, even after much effort to reduce their use. According to the Korean antimicrobial resistance surveillance system, the resistance rates of many bacteria are increasing. The resistance rate of Acinetobacter baumannii to imipenem in Korea increased to 85% in 2015, representing a major public threat. The reports of increased carbapenem resistance in Enterobacteriaceae are worrisome. More importantly, some carbapenem-resistant Enterobacteriaceae may result from the production of carbapenemases, which break down carbapenems. There are relatively few treatment options for extensively drug-resistant A. baumannii and carbapenem-resistant Enterobacteriaceae. Most reports are retrospective observational studies. Because there are little published data from randomized controlled trials, more data assessing antimicrobial treatment for extensively drug-resistant A. baumannii and carbapenem-resistant Enterobacteriaceae are needed to make treatment recommendations.

A Systematic Review and Meta-analyses of the Clinical Epidemiology of Carbapenem-Resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) are major health care-associated pathogens and responsible for hospital outbreaks worldwide. To prevent a further increase in CRE infections and to improve infection prevention strategies, it is important to summarize the current knowledge about CRE infection prevention in hospital settings. This systematic review aimed to identify risk factors for CRE acquisition among hospitalized patients. In addition, we summarized the environmental sources/reservoirs and the most successful infection prevention strategies related to CRE. A total of 3,983 potentially relevant articles were identified and screened. Finally, we included 162 studies in the systematic review, of which 69 studies regarding risk factors for CRE acquisition were included in the random-effects meta-analysis studies. The meta-analyses regarding risk factors for CRE acquisition showed that the use of medical devices generated the highest pooled estimate (odds ratio [OR] = 5.09; 95% confidence interval [CI] = 3.38 to 7.67), followed by carbapenem use (OR = 4.71; 95% CI = 3.54 to 6.26). To control hospital outbreaks, bundled interventions, including the use of barrier/contact precautions for patients colonized or infected with CRE, are needed. In addition, it is necessary to optimize the therapeutic approach, which is an important message to infectious disease specialists, who need to be actively involved in a timely manner in the treatment of patients with known CRE infections or suspected carriers of CRE.

Establishment of Experimental Murine Peritonitis Model with Hog Gastric Mucin for Carbapenem-Resistant Gram-Negative Bacteria

Animal models are essential to studies of infectious diseases. The use of mice to test bacterial infection has been extensively reported. However, methods applied to clinical isolates, particularly for carbapenem-resistant bacteria, must be tailored according to the infection models and bacteria used. In this study, we infected 6-week-old female BALB/c mice intraperitoneally with different strains of resistant bacteria plus 3% hog gastric mucin. This method was found to be efficient and readily applicable for investigation of carbapenem-resisant Gram-negative pathogens (e.g., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii) detected in Korea.