Impact of Multidrug-Resistant Organisms on Severe Acquired Brain Injury Rehabilitation: An Observational Study

Healthcare-associated infections (HAIa) and antimicrobial resistance are expected to be the next threat to human health and are most frequent in people with severe acquired brain injury (SABI), who can be more easily colonized by multidrug-resistant organisms (MDROs). The study's aim is to investigate the impact of MDRO colonizations and infections on SABI rehabilitation outcomes. This retrospective observational study was performed in a tertiary referral specialized rehabilitation hospital. The main outcomes were the presence of carbapenemase-producing Enterobacteriaceae (CPE) colonization, type and timing of HAI and MDRO HAI, and the number of CPE transmissions. We included 48 patients, 31% carrying CPE on admission and 33% colonized during the hospitalization. A total of 101 HAI were identified in 40 patients, with an overall incidence of 10.5/1000 patient days. Some 37% of patients had at least one MDRO infection, with a MDRO infection incidence of 2.8/1000 patient days. The number of HAIs was significantly correlated with the length of stay (LOS) (r = 0.453, p = 0.001). A significant correlation was found between colonization and type of hospital room (p = 0.013). Complications and HAI significantly affected LOS. We suggest that CPE carriers might be at risk of HAI and worse outcomes compared with non-CPE carriers.

Healthcare-associated infections and antimicrobial resistance in severe acquired brain injury: a retrospective multicenter study

Background

Recent studies underscore that healthcare-associated infections (HAIs) and multidrug-resistant (MDR) HAIs affect rehabilitation outcomes and hospital length of stay (LOS) for severe acquired brain injury (sABI).

Objective

This study aimed to estimate HAI incidence in different sABI rehabilitation settings and determine risk factors and HAI impact on neuromotor and cognitive recovery.

Methods

We conducted a retrospective multicenter study in two semi-intensive units (SICUs), two high-specialty post-acute units (PAUs), and one long-term care (LTC) rehabilitation facility. Data extraction was performed by experienced clinicians, using a structured Excel file and they agreed upon criteria for case definitions of healthcare. The main outcome measures were the HAI and MDR HAI incidence and the LOS, the functional recovery was measured using the Level of Cognitive Functioning and Disability Rating Scale.

Results

There were 134 sABI participants. The calculation of the probability level was adjusted for three pairwise comparisons among settings (0.05/3 = 0.017). The HAI and MDR HAI incidences were significantly higher in SICU (3.7 and 1.3 per 100 person-days) than in other settings (LTC: 1.9, p = 0.034 and 0.5, p = 0.026; PAU: 1.2, p < 0.001 and 0.3, p < 0.001). HAI and MDR HAI risk variables included older age, an increased number of devices, and carbapenemase-producing Enterobacteriaceae (CPE) colonization, while a high prealbumin plasma value seemed to have a protective effect.

Conclusion

HAIs are related to longer LOS, and colonization is associated with poor prognosis and poor functional outcomes with reduced ability to achieve the cognitive capacity of self-care, employability, and independent living. The need to ensure the protection of non-colonized patients, especially those with severe disabilities on admission, is highlighted.

First Report of OXA-181-Producing Enterobacterales Isolates in Latin America

We characterized five carbapenemase-producing Enterobacterales (CPE) isolates from two health care institutions in Lima, Peru. The isolates were identified as Klebsiella pneumoniae (n = 3), Citrobacter portucalensis (n = 1), and Escherichia coli (n = 1). All were identified as blaOXA-48-like gene carriers using conventional PCR. Whole-genome sequencing found the presence of the blaOXA-181 gene as the only carbapenemase gene in all isolates. Genes associated with resistance to aminoglycosides, quinolones, amphenicols, fosfomycins, macrolides, tetracyclines, sulfonamides, and trimethoprim were also found. The plasmid incompatibility group IncX3 was identified in all genomes in a truncated Tn6361 transposon flanked by ΔIS26 insertion sequences. The qnrS1 gene was also found downstream of blaOXA-181, conferring fluoroquinolone resistance to all isolates. CPE isolates harboring blaOXA-like genes are an increasing public health problem in health care settings worldwide. The IncX3 plasmid is involved in the worldwide dissemination of blaOXA-181, and its presence in these CPE isolates suggests the wide dissemination of blaOXA-181 in Peru. IMPORTANCE Reports of carbapenemase-producing Enterobacterales (CPE) isolates are increasing worldwide. Accurate detection of the β-lactamase OXA-181 (a variant of OXA-48) is important to initiate therapy and preventive measures in the clinic. OXA-181 has been described in CPE isolates in many countries, often associated with nosocomial outbreaks. However, the circulation of this carbapenemase has yet to be reported in Peru. Here, we report the detection of five multidrug-resistant CPE clinical isolates harboring blaOXA-181 in the IncX3-type plasmid, a potential driver of dissemination in Peru.

Genomic epidemiology of nosocomial carbapenemase-producing Citrobacter freundii in sewerage systems in the Helsinki metropolitan area, Finland

Multi-drug resistance is emerging in Citrobacter freundii, which is the third most common carbapenemase-producing (CP) Enterobacteriaceae in humans in Finland due to recent outbreaks. The objective of this study was to determine if wastewater surveillance (WWS) could detect CP C. freundii strains causing infections in humans. Selective culturing was used to isolate CP C. freundii from the hospital environment, hospital wastewater, and untreated municipal wastewater in Helsinki, Finland, between 2019 and 2022. Species were identified using MALDI-TOF, and presumptive CP C. freundii isolates were subjected to antimicrobial susceptibility testing and further characterized by whole genome sequencing. A genomic comparison was conducted to compare isolates collected from the hospital environment, untreated municipal wastewater, and a selection of isolates from human specimens from two hospitals in the same city. We also examined the persistence of CP C. freundii in the hospital environment and the impact of our attempts to eradicate it. Overall, 27 blaKPC - 2-carrying C. freundii were detected in the hospital environment (ST18; n = 23 and ST8; n = 4), while 13 blaKPC - 2-carrying C. freundii (ST8) and five blaVIM - 1-carrying (ST421) C. freundii were identified in untreated municipal wastewater. CP C. freundii was not identified in hospital wastewater. We found three clusters (cluster distance threshold ≤ 10 allelic difference) after comparing the recovered isolates and a selection of isolates from human specimens. The first cluster consisted of ST18 isolates from the hospital environment (n = 23) and human specimens (n = 4), the second consisted of ST8 isolates from the hospital environment (n = 4), untreated municipal wastewater (n = 6), and human specimens (n = 2), and the third consisted of ST421 isolates from the untreated municipal wastewater (n = 5). Our results support previous studies suggesting that the hospital environment could act as a source of transmission of CP C. freundii in clinical settings. Furthermore, the eradication of CP Enterobacteriaceae from the hospital environment is challenging. Our findings also showed that CP C. freundii is persistent throughout the sewerage system and demonstrate the potential of WWS for detecting CP C. freundii.

Clinical Characteristics and Associated Factors for Mortality in Patients with Carbapenem-Resistant Enterobacteriaceae Bloodstream Infection

BACKGROUND

Bloodstream infection (BSI) caused by carbapenem-resistant Enterobacteriaceae (CRE) significantly influences patient morbidity and mortality. We aimed to identify the characteristics, outcomes, and risk factors of mortality in adult patients with CRE bacteremia and elucidate the differences between carbapenemase-producing (CP)-CRE BSI and non-CP-CRE BSI.

METHODS

This retrospective study included 147 patients who developed CRE BSI between January 2016 and January 2019 at a large tertiary care hospital in South Korea. The patient demographic characteristics and clinical and microbiological data including the Enterobacteriaceae species and carbapenemase type were obtained and analyzed.

RESULTS

Klebsiella pneumoniae was the most commonly detected pathogen (80.3%), followed by Escherichia coli (15.0%). In total, 128 (87.1%) isolates were found to express carbapenemase, and most CP-CRE isolates harbored bla_KPC. The 14-day and 30-day mortality rates for CRE BSI were 34.0% and 42.2%, respectively. Higher body mass index (odds ratio (OR), 1.123; 95% confidence interval (CI), 1.012-1.246; p = 0.029), higher sequential organ failure assessment (SOFA) score (OR, 1.206; 95% CI, 1.073-1.356; p = 0.002), and previous antibiotic use (OR, 0.163; 95% CI, 0.028-0.933; p = 0.042) were independent risk factors for the 14-day mortality. A high SOFA score (OR, 1.208; 95% CI; 1.081-0.349; p = 0.001) was the only independent risk factor for 30-day mortality. Carbapenemase production and appropriate antibiotic treatment were not associated with high 14- or 30-day mortality rates.

CONCLUSIONS

Mortality from CRE BSI was related to the severity of the infection rather than to carbapenemase production or antibiotic treatment, showing that efforts to prevent CRE acquisition rather than treatment following CRE BSI detection would be more effective at reducing mortality.

Dissemination of carbapenemase-producing Enterobacteriaceae and associated resistance determinants through global food systems

Antimicrobial agents are a critical component of modern healthcare systems, fulfilling a core function in patient care and improving individual patient outcomes and consequently overall public health. However, the efficacy of antimicrobial interventions is being consistently eroded by the emergence and dissemination of various antimicrobial resistance (AMR) mechanisms. One highly valued class of antimicrobial compounds is carbapenems, which retain efficacy in treating most multidrug-resistant infections and are considered "last line" agents. Therefore, recent trends in proliferation of carbapenem resistance (CR) via dissemination of carbapenemase-encoding genes among members of the Enterobacteriaceae family pose a significant threat to public health. While much of the focus relating to this has been on nosocomial environments, community-acquired carbapenemase-producing Enterobacteriaceae (CPE) infections and their associated transmission routes are less well studied. Among these community-associated vectors, the role of food chains and contaminated foods is important, since Enterobacteriaceae occupy niches within these settings. This review examines foodborne CPE transmission by exploring how interactions within and between food, the food chain, and agriculture not only promote and disseminate CPE, but also create reservoirs of mobile genetic elements that may lead to further carbapenemase gene proliferation both within and between microbial communities. Additionally, recent developments regarding the global occurrence and molecular epidemiology of CPEs in food chains will be reviewed.

Epidemiology and Risk Factors of Carbapenemase-Producing Enterobacteriaceae Acquisition and Colonization at a Korean Hospital over 1 Year

Background: Carbapenemase-producing Enterobacteriaceae (CPE) are known to be primarily responsible for the increasing spread of carbapenem-resistant Enterobacteriaceae and have therefore been targeted for preventing transmission and appropriate treatment. This study aimed to describe the clinical and epidemiological characteristics and risk factors of CPE infection in terms of acquisition and colonization. Methods: We examined patients' hospital data, including active screening on patients' admission and in intensive care units (ICUs). We identified risk factors for CPE acquisition by comparing the clinical and epidemiological data of CPE-positive patients between colonization and acquisition groups. Results: A total of 77 CPE patients were included (51 colonized and 26 acquired). The most frequent Enterobacteriaceae species was Klebsiella pneumoniae. Among CPE-colonized patients, 80.4% had a hospitalization history within 3 months. CPE acquisition was significantly associated with treatment in an ICU [adjusted odds ratio (aOR): 46.72, 95% confidence interval (CI): 5.08-430.09] and holding a gastrointestinal tube (aOR: 12.70, 95% CI: 2.61-61.84). Conclusions: CPE acquisition was significantly associated with ICU stay, open wounds, holding catheters or tubes, and antibiotic treatment. Active CPE screening should be implemented on admission and periodically for high-risk patients.

Identification and Preliminary Hierarchisation of Selected Risk Factors for Carbapenemase-Producing Enterobacteriaceae (CPE) Colonisation: A Prospective Study

Drug-resistant bacteria are one of the main reasons of deaths worldwide. One of the significant groups of these bacteria are carbapenemase-producing Enterobacteriaceae (CPE). The goal of this cross-sectional study was the identification and hierarchisation of selected risk factors of CPE colonisation. To achieve that goal, we examined 236 patients for the presence of CPE using the standard method of anal swabs. The patients were divided into three groups: hospitalised patients; those chronically dialysed; those requiring home care. A very thorough medical interview was conducted for comorbidities. A statistical analysis relationship between comorbidities and locations of the patient's stay with the positive result of the culture was investigated. A significant relationship was demonstrated between the positive result of the culture and confirmed dementia, heart failure, connective tissue diseases, and established irregularities in the level of leukocytes. No significant relationship was demonstrated with the remaining comorbidities considered in the study. Afterwards these factors were compared for importance for the assessment of risk of a positive swab result-the biggest importance was found in establishing connective tissue disease. Next were dementia, abnormal values of leukocytes, heart failure, and at the end, stay at the orthopaedics ward. Conclusions: The study identified asymptomatic carriers of CPE, which demonstrates the need for further studies in order to identify infection risk factors. The connective tissue diseases are the most important variable which enable the prediction of CPE colonisation-the next ones are dementia, abnormal values of leukocytes, heart failure, and stay at the orthopaedics ward.

Spread of Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates Producing NDM-Type Metallo-β-Lactamase in Myanmar

A total of 38 isolates of carbapenem-resistant Klebsiella pneumoniae harboring blaNDM were obtained during surveillance of 10 hospitals in Myanmar. Of these 38 isolates, 19 (50%) harbored genes encoding 16S rRNA methylases, such as armA or rmtB. The K. pneumoniae strains tested belonged to 17 sequence types (STs), including the high-risk clonal lineages ST101 and ST147. The ST101 and ST147 isolates carried IncFII plasmids harboring blaNDM-5 and IncFIB(pQil) plasmids harboring blaNDM-1, respectively. These results indicate that IncFII plasmids harboring blaNDM-5 and IncFIB(pQil) plasmids harboring blaNDM-1 have been spreading in K. pneumoniae ST101 and ST147 isolates, respectively, in Myanmar. IMPORTANCE The emergence of carbapenem-resistant K. pneumoniae has become a serious problem in medical settings worldwide. The present study demonstrated that carbapenem-resistant K. pneumoniae strains have been spreading in medical settings in Myanmar. In particular, plasmid genes encoding NDMs and 16S rRNA methylases have been spreading in K. pneumoniae high-risk clones.

Occurrence and Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Strains Isolated from Hospitalized Patients in Poland-A Single Centre Study

The global emergence and spread of genes responsible for the production of ESBL (extended-spectrum beta-lactamases) and carbapenemases in Klebsiella pneumoniae isolates poses a serious threat to public health. The aim of this study was to retrospectively analyze the frequency of occurrence and drug resistance of selected alarm agents isolated from patients of the specialist hospital in Wrocław. A total of 13,528 clinical materials collected from patients of a specialist hospital in Wrocław were analyzed in the period from 1 January 2020 to 31 December 2020. Overall, 3894 bacterial strains were isolated from clinical materials, including 416 K. pneumoniae isolates. K. pneumoniae that showed resistance to ETP (ertapenem) and/or MEM (meropenem) were tested using phenotypic tests for the detection of KPC (carbapenemase-producing Klebsiella), MBL (metallo-β-lactamase) and OXA-48 (oxacilinase-48) carbapenemases. In the case of a positive or doubtful result of the phenotypic test, immunochromatographic tests and the CarbaNP test were performed. In total, 58 K. pneumoniae isolates resistant to 1 or more carbapenem antibiotics were isolated. Of the 58 strains, 16 (27.6%) were isolated from rectal swabs conducted on CPE (carbapenemase-producing Enterobacteriaceae) carriers. In the case of CRE (carbapenem-resistant Enterobacteriaceae) K. pneumoniae, carbapenemases were detected in 28/58 (48.3%) isolates. Notably, 23/28 K. pneumoniae isolates produced MBL/NDM (New Delhi metallo-β-lactamase) (82.1%), 5/28 produced VIM (Verona-intergon-encoded metallo-β-lactamase) (14.3%), and one produced MBL/NDM + OXA-48. Carbapenemases were detected in 13 of 16 (81.3%) carbapenem-resistant K. pneumoniae isolates derived from rectal swabs. The significant participation of CRE and CPE isolates in the infections proves the need to test patients admitted to hospital wards for their status as a CPE carrier in order to limit the emergence of new epidemic outbreaks.

Population Analysis Profiling: Is It Still the Gold Standard for the Determination of Heteroresistance in Carbapenemase-Producing Enterobacteriaceae?

Heteroresistance is the phenomenon wherein subpopulations of presumed isogenic bacteria show varied antibiotic susceptibilities, and the current gold standard for heteroresistance determination is population analysis profiling (PAP). However, when we conducted PAP to confirm carbapenem-heteroresistance in Enterobacteriaceae, we found some isolates that did not seem heteroresistant despite meeting PAP criteria. Here, we elaborate on the validity of PAP for heteroresistance determination, especially among carbapenemase-producing Enterobacteriaceae (CPE). We revealed that the bacterial cells that were originally inviable on the selective agar supplemented with a high concentration of meropenem were occasionally viable, likely owing to the hydrolysis of carbapenems by carbapenemases produced by dying cells, mimicking the emergence of subpopulations with enhanced resistance. PAP for CPE is highly affected by carbapenemases produced by the dying populations, and may not appropriately detect heterogeneity in carbapenem resistance among seemingly isogenic clones.

Carbapenemase producing Enterobacteriaceae: Environmental reservoirs as primary targets for control and prevention strategies

Carbapenemase-producing Enterobacteriaceae (CPE) have become one of the greatest public health challenges globally. In the past decade, antimicrobial resistance (AMR) was viewed as a clinical problem in many parts of the world; hence, the role and magnitude of the contribution of the environment were not well appreciated. This review article was done with online published articles extracted from different databases using search terms related to the work. Evidence has shown that there exists the presence of carbapenemase genes in the environment, consequently fuelling the dissemination with alarming consequences. CPE when acquired causes life-threatening infections in humans. The health and economic impact of these infections are numerous, including treatment failure due to limited therapeutic options which hamper the containment of infectious diseases, further contaminating the environment and worsening the public health challenge. It is a well-known fact that the rate of emergence of resistant genes has outpaced the production of new antimicrobial agents, so it is pertinent to institute effective environmental measures to combat the spread of AMR organisms before it will completely gain a foothold and take us back to 'the pre-antibiotic era'. Environmental sources and reservoirs of resistant genes should therefore be amongst the primary targets for the control and prevention of the spread of resistant genes in the environment. This calls for the effective implementation of the 'one health' strategy with stakeholders committed to the design and enforcement of environmental mitigation policies and guidelines.

Carbapenemase-producing Enterobacteriaceae in an inpatient post-acute care facility: impact on time to functional recovery

BACKGROUND

The carriage of carbapenemase-producing Enterobacteriaceae (CPE) might lengthen the time to functional recovery (TTFR) for inpatients in post-acute care (PAC) units.

OBJECTIVE

We aimed to assess the impact of CPE carriage on TTFR in a PAC facility.

METHODS

This 2-year retrospective cohort study included 20 CPE-positive patients and 54 CPE-negative patients admitted to 3 PAC units (general, orthopaedic and neurologic rehabilitation units) in a teaching hospital from January 2017 to December 2019. Potential risk factors and demographic data were collected from patients' medical records, the French national hospital discharge database, and the hospital's CPE surveillance database. Functional recovery was defined as the median difference in functional independence measure (FIM) between admission and discharge from each unit. Survival analysis and multiple Cox regression models were used to predict the TTFR and identify factors associated with functional recovery.

RESULTS

The overall median [interquartile range] TTFR was 50 days [36-66]. Longer median TTFR was associated with CPE carriage (63 vs 47 days in the CPE-negative group; adjusted hazard ratio (aHR) 0.35, 95% CI 0.13-0.97) and presence of a peripheral venous catheter (aHR 3.51, 1.45-8.46); shorter TTFR was associated with admission to an orthopaedic versus general rehabilitation unit (aHR 3.11, 1.24-7.82).

CONCLUSIONS

CPE carriage in inpatient PAC facilities was associated with long TTFR. Further studies are needed to explore the mechanisms involved in these adverse events and to identify possible preventive measures.

In vitro effectiveness of biapenem against IMP-producing Enterobacteriaceae

The options available for treating infections with carbapenemase-producing Enterobacteriaceae (CPE) are limited; with the increasing threat of these infections, new treatments are urgently needed. Biapenem (BIPM) is a carbapenem, and limited data confirming its in vitro killing effect against CPE are available. In this study, we examined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of BIPM for 14 IMP-1-producing Enterobacteriaceae strains isolated from the Okayama region in Japan. The MICs against almost all the isolates were lower than 0.5 µg ml^-1, indicating susceptibility to BIPM, while approximately half of the isolates were confirmed to be bacteriostatic to BIPM. However, initial killing to a 99.9 % reduction was observed in seven out of eight strains in a time-kill assay. Despite the small data set, we concluded that the in vitro efficacy of BIPM suggests that the drug could be a new therapeutic option against infection with IMP-producing CPE.

Epidemiology and Transmission of Carbapenemase-Producing Enterobacteriaceae in a Health Care Network of an Acute-Care Hospital and Its Affiliated Intermediate- and Long-Term-Care Facilities in Singapore

Movement of patients in a health care network poses challenges for the control of carbapenemase-producing Enterobacteriaceae (CPE). We aimed to identify intra- and interfacility transmission events and facility type-specific risk factors of CPE in an acute-care hospital (ACH) and its intermediate-term and long-term-care facilities (ILTCFs). Serial cross-sectional studies were conducted in June and July of 2014 to 2016 to screen for CPE. Whole-genome sequencing was done to identify strain relatedness and CPE genes (bla_IMI, bla_IMP-1, bla_KPC-2, bla_NDM-1, and bla_OXA-48). Multivariable logistic regression models, stratified by facility type, were used to determine independent risk factors. Of 5,357 patients, half (55%) were from the ACH. CPE prevalence was 1.3% in the ACH and 0.7% in ILTCFs (P = 0.029). After adjusting for sociodemographics, screening year, and facility type, the odds of CPE colonization increased significantly with a hospital stay of ≥3 weeks (adjusted odds ratio [aOR], 2.67; 95% confidence interval [CI], 1.17 to 6.05), penicillin use (aOR, 3.00; 95% CI, 1.05 to 8.56), proton pump inhibitor use (aOR, 3.20; 95% CI, 1.05 to 9.80), dementia (aOR, 3.42; 95% CI, 1.38 to 8.49), connective tissue disease (aOR, 5.10; 95% CI, 1.19 to 21.81), and prior carbapenem-resistant Enterobacteriaceae (CRE) carriage (aOR, 109.02; 95% CI, 28.47 to 417.44) in the ACH. For ILTCFs, presence of wounds (aOR, 5.30; 95% CI, 1.01 to 27.72), respiratory procedures (aOR, 4.97; 95% CI, 1.09 to 22.71), vancomycin-resistant enterococcus carriage (aOR, 16.42; 95% CI, 1.52 to 177.48), and CRE carriage (aOR, 758.30; 95% CI, 33.86 to 16,982.52) showed significant association. Genomic analysis revealed only possible intra-ACH transmission and no evidence for ACH-to-ILTCF transmission. Although CPE colonization was predominantly in the ACH, risk factors varied between facilities. Targeted screening and precautionary measures are warranted.

Oral Capsulized Fecal Microbiota Transplantation for Eradication of Carbapenemase-producing Enterobacteriaceae Colonization With a Metagenomic Perspective

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE) infections lead to considerable morbidity and mortality. We assessed the potential of fecal microbiota transplantation (FMT) to eradicate CPE carriage and aimed to explain failure or success through microbiome analyses.

METHODS

In this prospective cohort study, all consenting eligible CPE carriers received oral capsulized FMT for 2 days. Primary outcome was CPE eradication at 1 month, defined by 3 consecutive negative rectal swabs, the last also negative for carbapenemase gene by polymerase chain reaction. Comprehensive metagenomics analysis of the intestinal microbiome of donors and recipients before and after FMT was performed.

RESULTS

Fifteen CPE carriers received FMT, 13 of whom completed 2 days of treatment. CPE eradication at 1 month was successful in 9/15 and 9/13, respectively. Bacterial communities showed significant changes in both beta and alpha diversity metrics among participants who achieved CPE eradication that were not observed among failures. Post-FMT samples' beta-diversity clustered according to the treatment outcome, both in taxonomy and in function. We observed a significant decrease in beta diversity in participants who received post-FMT antibiotics. Enterobacteriaceae abundance decreased in post-FMT samples of the responders but increased among failures. Functionally, a clear demarcation between responders (who were similar to the donors) and failures was shown, driven by antimicrobial resistance genes.

CONCLUSIONS

Our study provides the biological explanation for the effect of FMT against CPE carriage. Decolonization of CPE by FMT is likely mediated by compositional and functional shifts in the microbiome. Thus, FMT might be an efficient strategy for sustained CPE eradication.

CLINICAL TRIALS REGISTRATION

NCT03167398.

Design of Rapid Detection System for Five Major Carbapenemase Families (bla KPC, bla NDM, bla VIM, bla IMP and bla OXA-48-Like) by Colorimetric Loop-Mediated Isothermal Amplification

Purpose

Carbapenemase-producing Enterobacteriaceae (CPE) infection constitutes a public health threat. Timely and efficient diagnosis is of paramount importance for prompt and effective therapy. In order to quickly and comprehensively detect the five major families of carbapenemases (bla_KPC, bla_NDM, bla_VIM, bla_IMP, and bla_OXA-48-like), colorimetric loop-mediated isothermal amplification (LAMP) was employed.

Materials and Methods

Five sets of LAMP primers were designed, each of which can, respectively, amplify all the carbapenemase subtypes described in this work. Twenty whole genome sequencing-verified-“standard strains”, including 1 bla_NDM-1, 1 bla_NDM-5, 1 bla_NDM-6, 1 bla_NDM-7, 2 bla_IMP-4, 1 bla_IMP-8, 2 bla_KPC-2, 1 bla_KPC-3, 1 bla_KPC-4, 1 bla_KPC-5, 1 bla_KPC-6, 1 bla_KPC-7, 1 bla_OXA-48 and 1 bla_OXA-181 carrier, and 1 bla_VIM and bla_OXA-244, 1 bla_KPC-2 and bla_IMP-4, 1 bla_KPC-2 and bla_VIM-1 and 1 bla_KPC-2 and bla_NDM-1-co-carriers, were used to establish a 25-microliter visual LAMP reaction system (kept at 65°C for 30 minutes in water bath). Color change from bright pink to yellow indicated positive amplification. In addition, 126 pre-verified clinical carbapenem-resistant Enterobacteriaceae (CRE) isolates, including 65 CPE (23 bla_NDM, 2 bla_OXA-48-like, 1 bla_KPC and bla_VIM, 2 bla_IMP, and 37 bla_KPC carriers) and 61 non-CPE, were also detected.

Results

With the lowest detection limit of 10 colony forming units (CFU) per reaction for LAMP and 10³ CFU per reaction for PCR, the LAMP system demonstrated dramatically higher sensitivity while retaining the same specificity. Furthermore, we demonstrated concordant results between the two methods for the 126 clinical isolates.

Conclusion

Therefore, LAMP could be used for rapid identification of the five major carbapenemase gene families in routine clinical laboratories.

Neonates with Maternal Colonization of Carbapenemase-Producing, Carbapenem-Resistant Enterobacteriaceae: A Mini-Review and a Suggested Guide for Preventing Neonatal Infection

Carbapenemase-producing, carbapenem-resistant Enterobacteriaceae (CP-CRE) are highly drug-resistant Gram-negative bacteria. They include New Delhi metallo-ß-lactamase (NDM)-producing carbapenemase (50.4% of all species in Ontario). Antibiotic challenges for resistant bacteria in neonates pose challenges of unknown dosing and side effects. We report two antenatally diagnosed CP-CRE colonization scenarios with the NDM 1 gene. The case involves extreme preterm twins who had worsening respiratory distress at birth requiring ventilator support, with the first twin also having cardiovascular instability. They were screened for CP-CRE, and a polymyxin antibiotic commenced. In the delivery room, neonatal intensive care unit (NICU) and the follow-up clinic, in collaboration with the interdisciplinary group, contact precautions and isolation procedures were instituted. None of the infants exhibited infection with CP-CRE. Consolidating knowledge with regard to CP-CRE and modifying human behavior associated with its spread can mitigate potential negative consequences. This relates to now and later, when travel and prolific human to human contact resumes, from endemic countries, after the current COVID-19 pandemic. Standardized efforts to curb the acquisition of this infection would be judicious given the challenges of treatment and continued emerging antibiotic resistance. Simple infection control measures involving contact precautions, staff education and parental cohorting can be useful and cost-effective in preventing transmission. Attention to NICU specific measures, including screening of at-risk mothers (invitro fertilization conception) and their probands, careful handling of breastmilk, judicious antibiotic choice and duration of treatment, is warranted. What does this study add? CP-CRE is a nosocomial infection with increasing incidence globally, and a serious threat to public health, making it likely that these cases will present with greater frequency to the NICU team. Only a few similar cases have been reported in the neonatal literature. Current published guidelines provide a framework for general hospital management. Still, they are not specific to the NICU experience and the need to manage the parents' exposure and the infants. This article provides a holistic framework for managing confirmed or suspected cases of CP-CRE from the antenatal care through the NICU and into the follow-up clinic targeted at preventing or containing the spread of CP-CRE.

Antibiotic Resistance in Wastewater Treatment Plants and Transmission Risks for Employees and Residents: The Concept of the AWARE Study

Antibiotic resistance has become a serious global health threat. Wastewater treatment plants may become unintentional collection points for bacteria resistant to antimicrobials. Little is known about the transmission of antibiotic resistance from wastewater treatment plants to humans, most importantly to wastewater treatment plant workers and residents living in the vicinity. We aim to deliver precise information about the methods used in the AWARE (Antibiotic Resistance in Wastewater: Transmission Risks for Employees and Residents around Wastewater Treatment Plants) study. Within the AWARE study, we gathered data on the prevalence of two antibiotic resistance phenotypes, ESBL-producing E. coli and carbapenemase-producing Enterobacteriaceae, as well as on their corresponding antibiotic resistance genes isolated from air, water, and sewage samples taken from inside and outside of different wastewater treatment plants in Germany, the Netherlands, and Romania. Additionally, we analysed stool samples of wastewater treatment plant workers, nearby residents, and members of a comparison group living ≥1000 m away from the closest WWTP. To our knowledge, this is the first study investigating the potential spread of ESBL-producing E. coli, carbapenemase-producing Enterobacteriaceae, and antibiotic resistance genes from WWTPs to workers, the environment, and nearby residents. Quantifying the contribution of different wastewater treatment processes to the removal efficiency of ESBL-producing E. coli, carbapenemase-producing Enterobacteriaceae, and antibiotic resistance genes will provide us with evidence-based support for possible mitigation strategies.

Risk Factors for Intra-Abdominal Infections Caused by Carbapenemase-Producing Enterobacteriaceae in a Surgical Setting

Background: The aim of this study was to identify risk factors for acquisition of intra-abdominal infections (IAI) caused by carbapenemase-producing Enterobacteriaceae (CPE) in surgical patients. Methods: A matched case-control study was performed. We included all cases with CPE-related IAI acquired during admission to a general surgery department from January 2013 to December 2018, and they were matched with control subjects with IAI caused by non-resistant bacteria (ratio 1:3). Independent risk factors were obtained by logistic regression. Results: Forty patients with IAI-CPE were matched with 120 control subjects. Independent risk factors for acquisition of IAI-CPE were previous hospitalization (odds ratio [OR] 2.56; 95% confidence interval [CI] l 1.01-6.49; p = 0.047), digestive endoscopy (OR 4.11; 95% CI 1.40-12.07; p = 0.010), carbapenem therapy (OR 9.54; 95% CI 3.33-27.30; p < 0.001), and aminoglycoside use (OR 45.41; 95% CI 7.90-261.06; p < 0.001). Conclusions: Four clinical factors can identify patients at high-risk of IAI-CPE.

Multiplex Real-Time PCR Assay for Six Major Carbapenemase Genes

The global dissemination of carbapenemase-producing Enterobacteriaceae (CPE) is a major concern in public health. Due to the existence of the diversity of carbapenemases, development of an easily available, cost-effective multiplex detection assay for CPE is required worldwide. Using clinically available and reliable equipment, COBAS^® z480 (Roche Diagnostics K.K., Tokyo, Japan), we developed a multiplex real-time PCR assay for the detection of two combinations of carbapenemases; first, bla_NDM, bla_KPC, and bla_IMP (Set 1), and second, bla_GES, bla_OXA-48, and bla_VIM (Set 2). We constructed standard curves for each carbapenemase gene using serial dilutions of DNA standards, then applied reference or clinical isolates with each carbapenemase gene to this assay. The multiplex assay showed satisfactory accuracy to detect CPE genes, with the correlation coefficients of greater than 0.99 for all genotypes. The assay appropriately differentiated the reference or clinical strains harboring each carbapenemase gene without cross reactivity. Lastly, the assay successfully detected multiple genes without false-positive reactions by applying six clinical isolates carrying both NDM and OXA-48-like carbapenemase genes. Major advantages of our assay include multiplicity, simple operation, robustness, and speed (1 h). We believe that the multiplex assay potentially contributes to early diagnosis of CPE with a diverse genetic background.

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

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

In vitro Activity of Ceftazidime-Avibactam and Aztreonam-Avibactam Against Carbapenem-resistant Enterobacteriaceae Isolates Collected from Three Secondary Hospitals in Southwest China Between 2018 and 2019

Purpose

To assess the antimicrobial activities of ceftazidime/avibactam (CAZ/AVI) and aztreonam/avibactam (ATM/AVI) against carbapenem-resistant Enterobacteriaceae (CRE) isolates collected from three secondary hospitals in Southwest China between 2018 and 2019.

Materials and Methods

A total of 120 unique CRE clinical isolates were collected and carbapenemase genes were detected using PCR. Antimicrobial susceptibility was determined using standard broth microdilution method and the results were interpreted according to CLSI breakpoints.

Results

The 120 carbapenem-resistant strains included 92 Klebsiella pneumoniae, 10 Escherichia coli, 10 Enterobacter cloacae, five Klebsiella aerogenes, and three Klebsiella oxytoca isolates. Seventy-four percent of these 120 CRE isolates were collected from patients located in non-ICUs; 65.0% of these CRE isolates were collected from male patients; and 34.2% of these isolates were isolated from respiratory tracts. Four different carbapenemase genes were identified among 103 carbapenemase-producing Enterobacteriaceae (CPE) isolates, including bla _KPC-2 (n=77), bla _NDM-1 (n=16), bla _NDM-5 (n=12) and bla _IMP-4 (n=2). Overall, 21.7%, 37.5%, 40.8%, 75.0%, and 100% of the CRE strains were susceptible to levofloxacin, trimethoprim/sulfamethoxazole, amikacin, CAZ/AVI, and ATM/AVI, respectively. In addition, antimicrobial susceptibility testing showed that 96.7% isolates (n=116) were resistant to aztreonam, and the addition of avibactam (4 mg/L) significantly reduced the MICs of those aztreonam-resistant isolates by more than 128-fold (range: ≤0.125-4 mg/L), and 90.0% (n=108) of total 120 isolates were inhibited at ATM/AVI concentration ≤1 mg/L.

Conclusion

Our study revealed significant antimicrobial resistance among the CRE isolates against some commonly used antibiotics in three secondary Chinese hospitals. ATM/AVI exhibited potent activity against CRE isolates, including double carbapenemase-producing isolates, whereas CAZ/AVI was active against all KPC producers.

Bloodstream infections due to carbapenemase-producing Enterobacteriaceae in Italy: results from nationwide surveillance, 2014 to 2017

Following the rapid increase of infections due to carbapenemase-producing Enterobacteriaceae (CPE) in Italy, the national surveillance of bloodstream infections (BSI) due to CPE (Klebsiella pneumoniae and Escherichia coli) was instituted in 2013. All CPE-BSI cases reported to the surveillance in the years 2014-17 were analysed in order to investigate incidence rate (IR), trend, main individual characteristics and enzymes involved in CPE resistance. Throughout this period, 7,632 CPE-BSI cases (IR: 3.14/100,000 inhabitants) were reported from all 21 regions and autonomous provinces in Italy, with an increasing number of reported cases (2014: 1,403; 2015: 1,838; 2016: 2,183; 2017: 2,208). CPE-BSI cases mainly occurred in subjects aged over 60 years (70.9%) and more frequently in males (62.7%) than in females. Most of the cases originated in hospitals (87.2%), mainly in intensive care units (38.0%), and were associated with central or peripheral venous catheter use (23.9%) or with urinary tract infections (21.1%). Almost all CPE-BSI (98.1%) were due to K. pneumoniae carrying the K. pneumoniae carbapenemase (KPC) enzyme (95.2%). These data show that carbapenemase-producing K. pneumoniae are endemic in our country, causing a high number of BSI and representing a threat to patient safety.

Intra-Abdominal Infections by Carbapenemase-Producing Enterobacteriaceae in a Surgical Unit: Counting Mortality, Stay, and Costs

Background: Carbapenemase-producing Enterobacteriaceae (CPE)-related infections are a problem in public health at present, including intra-abdominal infections (IAI) and surgical populations. The aim of this study was to determine mortality and related risk factors, length of stay (LOS,) and costs for CPE-IAI in surgical patients. Patients and Methods: Review of CPE-related IAI acquired during admission in a general surgery department from January 2013 to December 2018. A mortality analysis was performed specifically in patients with CPE-IAI, and a global analysis of IAI including patients with CPE-IAI (cases) and matched patients with IAI by non-resistant bacteria (controls). Results: Forty patients with CPE-IAI were included, OXA-48-producing Klebsiella pneumoniae was present in 85%. Global mortality rate at 30 days for CPE-IAI was 17.5%; mortality-related factors were: solid tumor (p = 0.009), metastatic disease (p = 0.005), immunodeficiency (p = 0.039), blood transfusion (p = 0.009), and septic shock (p = 0.011). Predictors related to mortality for IAI in the global analysis included age (p = 0.046), Charlson index (p = 0.036), CPE isolation (p = 0.003), and septic shock (p < 0.001). Median global LOS was 43 days (IQR 27-64) in patients with CPE-IAI, and 27 days (IQR 18-35) in controls (p < 0.001). Median global cost of admission was $31,671 (IQR 14,006-55,745) for patients with CPE-IAI and $20,306 (IQR 11,974-27,947) for controls (p = 0.064). The most relevant locations of underlying disease for CPE-IAI were: colorectal (32.5%) with 57-day LOS (IQR 34-65) and cost of $42,877 (IQR 18,780-92,607), and pancreas (25%) with 60-day LOS (IQR 32-99) and cost of $56,371 (IQR 32,590-113,979). Conclusion: Carbapenemase-producing Enterobacteriaceae-related IAI is associated with substantial mortality, LOS, and costs. Factors related to CPE-IAI mortality are solid tumor, metastatic disease, immunodeficiency, blood transfusion, and septic shock. Carbapenemase-producing Enterobacteriaceae isolation in IAI implies higher risk of mortality.

Metagenomic Characterization of Gut Microbiota of Carriers of Extended-Spectrum Beta-Lactamase or Carbapenemase-Producing Enterobacteriaceae Following Treatment with Oral Antibiotics and Fecal Microbiota Transplantation: Results from a Multicenter Randomized Trial

Background: The R-GNOSIS (Resistance in Gram-Negative Organisms: Studying Intervention Strategies) WP3 study was the first multicenter randomized clinical trial systematically investigating fecal microbiota transplantation (FMT) for intestinal decolonization of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE). Here, we characterized the temporal dynamics of fecal microbiota changes in a sub-cohort of the R-GNOSIS WP3 participants before and after antibiotics/FMT using whole metagenome shotgun sequencing. Methods: We sequenced fecal DNA obtained from 16 ESBL-E/CPE carriers having received oral colistin/neomycin followed by FMT and their corresponding seven donors. Ten treatment-naïve controls from the same trial were included. Fecal samples were collected at baseline (V0), after antibiotics but before FMT (V2) and three times after FMT (V3, V4 and V5). Results: Antibiotic treatment transiently decreased species richness and diversity and increased the abundance of antibiotic resistance determinants (ARDs). Bifidobacterium species, together with butyrate- and propionate-producing species from Lachnospiraceae and Ruminococcaceae families were significantly enriched in post-FMT microbiota of treated carriers. After FMT, the proportion of Enterobacteriaceae was lower compared to baseline but without statistical significance. Conclusions: Combined antibiotic and FMT treatment resulted in enrichment of species that are likely to limit the gut colonization by ESBL-E/CPE.

Healthcare-associated infections and antimicrobial resistance in Canadian acute care hospitals, 2014-2018

Background

Healthcare-associated infections (HAIs) and antimicrobial resistance (AMR) pose serious threats to the health of Canadians due to increased morbidity, mortality and healthcare costs. Epidemiologic and laboratory surveillance data, collected through the Canadian Nosocomial Infection Surveillance Program, are used to inform infection prevention and control and antimicrobial stewardship programs and policies. The objective of this study was to describe the epidemiologic and laboratory characteristics and trends of HAIs and AMR from 2014 to 2018 using surveillance data provided by Canadian hospitals participating in the Canadian Nosocomial Infection Surveillance Program.

Methods

Data were collected from 70 Canadian sentinel hospitals between January 1, 2014 and December 31, 2018 for Clostridioides difficile infection (CDI), methicillin-resistant Staphylococcus aureus bloodstream infections, vancomycin-resistant Enterococci bloodstream infections and carbapenemase-producing Enterobacteriaceae. Case counts, rates, outcome data, molecular characterization and antimicrobial resistance profiles are presented. Additionally, hospital-level Escherichia coli antibiogram data were collected and are described.

Results

Increases in rates per 10,000 patient-days were observed for methicillin-resistant S. aureus bloodstream infections (59%; 0.66-1.05, p=0.023) and vancomycin-resistant Enterococci bloodstream infections (143%; 0.14-0.34, p=0.023). However, CDI rates decreased by 12.5% between 2015 and 2018 (from 6.16-5.39, p=0.042). Carbapenemase-producing Enterobacteriaceae infection rates remained low and stable whereas colonization increased by 375% (0.04-0.19; p=0.014).

Conclusion

Ongoing efforts to prevent HAIs and reduce AMR in Canada require consistent, standardized surveillance data from acute care hospitals. Increased collaboration with provincial, territorial and international partners in infection prevention and control, as well as antimicrobial stewardship, will be essential in reducing the burden of observed HAIs (including antimicrobial resistant organisms).

The experience of 2 years in a tertiary teaching hospital in northern Portugal

Background:

The emergence of carbapenemase-producing Enterobacterales (CPE) represents a major public health threat. Our purpose was to evaluate a surveillance and cohorting program implemented in patients infected or carriers of CPE.

Methods:

A prospective registry of CPE carriers or infected patients was analyzed from October 2015 until December 2017. All inpatients presenting with CPE were included in a hospital cohort with dedicated healthcare staff and contact precaution measures.

Results:

A total of 480 patients were identified, of which 15.8% (n = 76) were infected. Men comprised 56.7% of the cohort (n = 272) and 69.2% (n = 332) were elderly. About 46.3% (n = 222) had a previous hospital admission and 81.7% (n = 392) had at least 1 antibiotic course in the previous 90 days. There was a decline in infected patients in 2017. Periodic and admission screenings accounted for 63% and 74% of cases in 2016 and 2017, with increased detection rate comparing with contact/investigation screenings. In 2017, significantly fewer patients were identified outside the admission/point of prevalence screening (P = .009). In 2017 the proportion of invasive carbapenem-resistant Klebsiella pneumoniae amongst CPE in our center was below the national average (2016: 13.3% vs 5.2%; 2017: 6.6% vs 8.6%). A reduction of the consumption of carbapenems was also observed in 2017.

Conclusion:

The implementation of the program has increased the number of patients identified by the preventive method and stabilized the emergence of new CPE cases. Furthermore, the program cohort compared well with the national picture, with a lower number of infected patients and a lower proportion of carbapenem-resistant K pneumoniae in invasive specimens. These indicators reflect the added value of the CPE surveillance and cohorting program.

In Vitro Efficacy of Meropenem-Cefmetazole Combination Therapy against New Delhi Metallo-β-lactamase-producing Enterobacteriaceae

BACKGROUND

Limited treatment options complicate management of infections with New Delhi metallo-β-lactamase (NDM)-producing organisms. The efficacy of combination therapy with meropenem (MEM) and cefmetazole (CMZ) was assessed against NDM-producing Enterobacteriaceae.

MATERIALS AND METHODS

Twelve Escherichia coli clinical isolates harbouring bla_NDM-1 and a positive control E. coli BAA-2469 harbouring bla_NDM-1 were studied. Minimum inhibitory concentrations (MICs) of MEM, ertapenem (ERT) and CMZ were determined by broth microdilution. Checkerboard and time-kill assays were performed to confirm the in vitro efficacy of the MEM/CMZ combination. Scanning electron microscopy, kinetic studies and whole-genome sequence analysis were used to determine the antimicrobial resistance mechanisms.

RESULTS

MICs of MEM, ERT and CMZ in monotherapy ranged from 8 to 32, 16 to 128, and 32 to 512 µg/mL, respectively. In the checkerboard assay, MEM/ERT resulted in no synergy, whereas MEM/CMZ showed a synergistic effect in all the tested isolates. Furthermore, the MIC of MEM in combination decreased by 2- to 8-fold compared with that of MEM alone. The time-kill study revealed a bactericidal effect in 4 of 13 isolates at 24 h. Scanning electron microscopy showed spheroidisation of the bacterial cell in the MEM/CMZ combination; this was not observed in single antibiotic conditions. Kinetic studies indicated CMZ was a better antagonist for NDM-1 than ERT. Whole-genome sequence analysis did not reveal any explainable differences between isolates susceptible and those non-susceptible to combination therapy.

CONCLUSION

In vitro studies showed the potential effectiveness of MEM/CMZ combination therapy against NDM-producing organisms.

Performance of a Novel Fluorogenic Assay for Detection of Carbapenemase-Producing Enterobacteriaceae from Bacterial Colonies and Directly from Positive Blood Cultures

Rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) is critical for appropriate treatment and infection control. We compared a rapid fluorogenic assay using a carbapenem-based fluorogenic probe with other phenotypic assays: modified carbapenem inactivation method (mCIM), Carba NP test (CNP), and carbapenemase inhibition test (CIT). A total of 217 characterized isolates of Enterobacteriaceae were included as follows: 63 CPE; 48 non-carbapenemase-producing carbapenem-resistant Enterobacteriaceae (non-CP-CRE); 53 extended-spectrum β-lactamase producers; and 53 third-generation-cephalosporin-susceptible isolates. The fluorogenic assay using bacterial colonies (Fluore-C) was conducted by lysing the isolates followed by centrifugation and mixing the supernatant with fluorogenic probe. In addition, for the fluorogenic assay using spiked blood culture bottles (Fluore-Direct), pellets were obtained via the saponin preparation method, which can directly identify the pathogens using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The fluorescence signal was measured over 50 min using a fluorometer. The fluorescent signal of CPE was significantly higher than that of non-CPE in both Fluore-C (median relative fluorescence units [RFU] [range], 5,814 [240 to 32,009] versus 804 [36 to 2,480], respectively; P < 0.0001) and Fluore-Direct (median RFU [range], 10,355 [1,689 to 31,463] versus 1,068 [428 to 2,155], respectively; P < 0.0001) tests. Overall, positive and negative percent agreements of Fluore-C, mCIM, CNP, CIT, and Fluore-Direct were 100% and 98.7%, 98.3% and 97.5%, 88.1% and 100%, 96.4% and 98.7%, and 98.3% and 98.1%, respectively. The relatively lower positive percent agreement (PPA) of CNP was mainly observed in OXA-type CPE. The fluorogenic assay showed excellent performance with bacterial colonies and also directly from positive blood cultures. We included many non-CP-CRE isolates for strict evaluation. The fluorogenic assay will be a useful tool for clinical microbiology laboratories.

Multiple β-Lactam Resistance Gene-Carrying Plasmid Harbored by Klebsiella quasipneumoniae Isolated from Urban Sewage in Japan

In our investigation of urban wastewater in Japan, carbapenem-resistant Klebsiella quasipneumoniae subsp. quasipneumoniae was isolated that carried the pTMSNI47-1 plasmid, which carries four β-lactamase genes and has transferability among Enterobacteriaceae. pTMSNI47-1 was found to encode a rarely reported carbapenemase, KHM-1. Cooperative effects of β-lactamases encoded by pTMSNI47-1 appeared to have broad-spectrum resistance to β-lactams. The detection of the KHM-1 gene in urban wastewater suggests that such a rare antimicrobial resistance (AMR) gene can be pooled in the environment, potentially emerging as an AMR determinant in a pathogen. When the number of β-lactamase resistance genes is increased in one plasmid, the transfer of this plasmid can confer broad-spectrum resistance to β-lactams, even if the individual gene confers narrow-spectrum resistance. The present study adds important information about the potential risk of sewage treatment plants as reservoirs and environmental suppliers of AMR genes, contributing to the public health from a One Health perspective.

The continuous emergence of carbapenemase-producing Enterobacteriaceae (CPE) presents a great public health challenge. Mitigation of CPE spread in the environment is crucial, particularly from a One Health perspective. Here we describe the isolation of CPE strain SNI47 from influent water of a sewage treatment plant in Japan. SNI47 was identified as Klebsiella quasipneumoniae subsp. quasipneumoniae by phylogenetic analysis and was resistant to β-lactams, including carbapenems. Of four plasmids detected from SNI47, the 185,311-bp IncA/C2 plasmid (pTMSNI47-1), which carried 10 drug resistance genes, including genes for four β-lactamases (bla_CTX-M-2, bla_DHA-1, bla_KHM-1, and bla_OXA-10), was transferred to Escherichia coli J53 via conjugation. The MICs of all tested β-lactams for the transconjugant were higher than for the recipient. We constructed recombinant plasmids, into which each β-lactamase gene was inserted, and used them to transform E. coli DH5α cells, demonstrating that KHM-1 enhanced carbapenem resistance. In addition, these β-lactamases were responsible for a wide-spectrum β-lactam resistance acquisition with mutual compensation. KHM-1, recognized as a rare type of metallo-β-lactamase, was detected in a transferable plasmid, from a sewage treatment plant, involved in horizontal gene transfer. The detection of such plasmids raises a health risk alarm for CPE dissemination.

IMPORTANCE In our investigation of urban wastewater in Japan, carbapenem-resistant Klebsiella quasipneumoniae subsp. quasipneumoniae was isolated that carried the pTMSNI47-1 plasmid, which carries four β-lactamase genes and has transferability among Enterobacteriaceae. pTMSNI47-1 was found to encode a rarely reported carbapenemase, KHM-1. Cooperative effects of β-lactamases encoded by pTMSNI47-1 appeared to have broad-spectrum resistance to β-lactams. The detection of the KHM-1 gene in urban wastewater suggests that such a rare antimicrobial resistance (AMR) gene can be pooled in the environment, potentially emerging as an AMR determinant in a pathogen. When the number of β-lactamase resistance genes is increased in one plasmid, the transfer of this plasmid can confer broad-spectrum resistance to β-lactams, even if the individual gene confers narrow-spectrum resistance. The present study adds important information about the potential risk of sewage treatment plants as reservoirs and environmental suppliers of AMR genes, contributing to the public health from a One Health perspective.

The Role of fosA in Challenges with Fosfomycin Susceptibility Testing of Multispecies Klebsiella pneumoniae Carbapenemase-Producing Clinical Isolates

With multidrug-resistant (MDR) Enterobacterales on the rise, a nontoxic antimicrobial agent with a unique mechanism of action such as fosfomycin seems attractive. However, establishing accurate fosfomycin susceptibility testing for non-Escherichia coli isolates in a clinical microbiology laboratory remains problematic. We evaluated fosfomycin susceptibility by multiple methods with 96 KPC-producing clinical isolates of multiple strains and species collected at a single center between 2008 and 2016.

With multidrug-resistant (MDR) Enterobacterales on the rise, a nontoxic antimicrobial agent with a unique mechanism of action such as fosfomycin seems attractive. However, establishing accurate fosfomycin susceptibility testing for non-Escherichia coli isolates in a clinical microbiology laboratory remains problematic. We evaluated fosfomycin susceptibility by multiple methods with 96 KPC-producing clinical isolates of multiple strains and species collected at a single center between 2008 and 2016. In addition, we assessed the presence of fosfomycin resistance genes from whole-genome sequencing (WGS) data using NCBI’s AMRFinder and custom HMM search. Susceptibility testing was performed using a glucose-6-phosphate-supplemented fosfomycin Etest and Kirby-Bauer disk diffusion (DD) assays, and the results were compared to those obtained by agar dilution. Clinical Laboratory and Standards Institute (CLSI) breakpoints for E. coli were applied for interpretation. Overall, 63% (60/96) of isolates were susceptible by Etest, 70% (67/96) by DD, and 88% (84/96) by agar dilution. fosA was detected in 80% (70/88) of previously sequenced isolates, with species-specific associations and alleles, and fosA-positive isolates were associated with higher MIC distributions. Disk potentiation testing was performed using sodium phosphonoformate to inhibit fosA and showed significant increases in the zone diameter of DD testing for isolates that were fosA positive compared to those that were fosA negative. The addition of sodium phosphonoformate (PPF) corrected 10/14 (71%) major errors in categorical agreement with agar dilution. Our results indicate that fosA influences the inaccuracy of susceptibility testing by methods readily available in a clinical laboratory compared to agar dilution. Further research is needed to determine the impact of fosA on clinical outcomes.

Antecedent Carbapenem Exposure as a Risk Factor for Non-Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae and Carbapenemase-Producing Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) can be mechanistically classified into carbapenemase-producing Enterobacteriaceae (CPE) and non-carbapenemase-producing carbapenem nonsusceptible Enterobacteriaceae (NCPCRE). We sought to investigate the effect of antecedent carbapenem exposure as a risk factor for NCPCRE versus CPE. Among all patients with CRE colonization and infection, we conducted a case-control study comparing patients with NCPCRE (cases) and patients with CPE (controls). The presence of carbapenemases was investigated with phenotypic tests followed by PCR for predominant carbapenemase genes. We included 843 unique patients with first-episode CRE, including 387 (45.9%) NCPCRE and 456 (54.1%) CPE. The resistance genes detected in CPEs were bla _NDM (42.8%), bla _KPC (38.4%), and bla _OXA-48-like (12.1%). After adjusting for confounders and clustering at the institutional level, the odds of prior 30-day carbapenem exposure was three times higher among NCPCRE than CPE patients (adjusted odds ratio [aOR], 3.48; 95% confidence interval [CI], 2.39 to 5.09; P < 0.001). The odds of prior carbapenem exposure and NCPCRE detection persisted in stratified analyses by Enterobacteriaceae species (Klebsiella pneumoniae and Escherichia coli) and carbapenemase gene (bla _NDM and bla _KPC). CPE was associated with male gender (aOR, 1.45; 95% CI, 1.07 to 1.97; P = 0.02), intensive care unit stay (aOR, 1.84; 95% CI, 1.24 to 2.74; P = 0.003), and hospitalization in the preceding 1 year (aOR, 1.42; 95% CI, 1.01 to 2.02; P = 0.05). In a large nationwide study, antecedent carbapenem exposure was a significant risk factor for NCPCRE versus CPE, suggesting a differential effect of antibiotic selection pressure.

Breakthrough bloodstream infections in critically ill non-neutropenic patients: higher incidence and better survival than non-breakthrough infections

Introduction. Breakthrough bloodstream infections (BSIs) are rare among non-neutropenic patients.Aim. Our goal was to determine the risk factors associated with development of breakthrough BSIs among critically ill non-neutropenic patients and its role in mortality.Methodology. During a 24-month period (August 2016 to July 2018), all BSIs among non-neutropenic patients hospitalized at the University General Hospital of Patras, Greece, were included. Antimicrobial resistance of isolates was interpreted according to EUCAST guidelines. BSIs were considered as breakthrough when blood cultures yielded a pathogen in a patient who, for at least the previous 72 h, had been receiving at least one antibiotic to which the isolated microorganism was susceptible.Results. Among 217 episodes of BSI, 118 (54.4 %) developed a breakthrough infection. Primary BSIs predominated (101; 46.5 %), followed by catheter-related BSIs (56; 25.8 %). Gram-negative bacteria represented the most common pathogens isolated (157; 72.4 %), followed by Gram-positive bacteria (36; 16.6 %) and fungi (36; 16.6 %). Factors independently associated with the development of breakthrough BSIs were immunosuppressive therapy, obesity (body mass index ≥30 kg m^{- 2}), infection by Gram-positive bacteria, noradrenaline dose during 24 h from BSI onset, prior use of colistin and antifungal treatment. Overall 14-day mortality was 23.0 % (50 patients). Multivariate analysis revealed noradrenaline dose during 24 h from BSI onset as an independent predictor of mortality, while appropriate empiric antimicrobial treatment and breakthrough BSI were identified as predictors of good prognosis.Conclusion. Breakthrough BSIs were common among critically ill non-neutropenic patients and these patients were associated with better survival because they were de facto receiving appropriate antibiotics.

Patient experience of hospital screening for carbapenemase-producing Enterobacteriaceae: A qualitative study

AIM

To explore patients' accounts of screening and being managed for colonisation with the antimicrobial resistant organism, carbapenemase-producing Enterobacteriaceae (CPE), when in hospital.

BACKGROUND

Antimicrobial resistance (AMR) has been identified as one of the biggest global health challenges of the 21st Century. As the threat from AMR grows, screening to identify patients who are colonised with resistant organisms such as CPE is becoming an increasingly important aspect of nursing practice, in order to reduce risk of transmission of infection within hospitals. There is currently little research evidence on the patient experience of hospital management of CPE colonisation.

METHODS

Qualitative semi-structured telephone interviews were undertaken, using a topic guide. Nine patients participated in the study. The data were analysed thematically, and rigour was maintained through peer review. The COREQ checklist was used.

RESULTS

Two main themes were identified: "I can't make sense of CPE," illustrating limitations in patients' understandings of CPE; and, "I feel as if they are saying it is my fault," indicating the feelings of responsibility and blame which patients experienced.

CONCLUSIONS

This paper contributes original evidence to the limited literature on patients' experiences of being colonised with CPE. The findings suggest that support and information provided for patients by healthcare professionals needs to be based on current evidence-based guidance on the nature of CPE and its implications for patient care, as well as being responsive to patients' emotional needs.

RELEVANCE TO CLINICAL PRACTICE

This study has international relevance for nursing practice. As the global threat of AMR grows, the demands on healthcare providers to manage resistant organisms and their implications for patient care within healthcare settings are increasing. Enabling healthcare professionals to engage sensitively with patients being managed for colonisation with CPE is paramount to providing patient-centred care.

Repeated Detection of Carbapenemase-Producing Escherichia coli in Gulls Inhabiting Alaska

Here, we report the first detection of carbapenemase-producing Escherichia coli in Alaska and in wildlife in the United States. Wild bird (gull) feces sampled at three locations in Southcentral Alaska yielded isolates that harbored plasmid-encoded bla _KPC-2 or chromosomally encoded bla _OXA-48 and genes associated with antimicrobial resistance to up to eight antibiotic classes.

EDTA-Modified Carbapenem Inactivation Method: a Phenotypic Method for Detecting Metallo-β-Lactamase-Producing Enterobacteriaceae

The increase in the prevalence and impact of infections caused by carbapenemase-producing Enterobacteriaceae is a global health concern. Therefore, rapid and accurate methods to detect these organisms in any clinical microbiology laboratory, including those in resource-limited settings, are essential to prevent and contain their spread. It is also important to differentiate between serine- and metal-dependent carbapenemases elaborated by carbapenemase-producing isolates for epidemiologic, infection control and prevention, and therapeutic purposes. Here, we describe the development and evaluation of the EDTA-modified carbapenem inactivation method (eCIM), an assay for discriminating between serine- and metal-dependent (i.e., metallo-β-lactamases [MBLs]) carbapenemases when used in conjunction with the modified carbapenem inactivation method (mCIM). The eCIM had an overall sensitivity and specificity of 100% and was adopted by the Clinical and Laboratory Standards Institute as a method to use in combination with the mCIM to identify MBL-producing Enterobacteriaceae.

Novel Enterobacter Lineage as Leading Cause of Nosocomial Outbreak Involving Carbapenemase-Producing Strains

We investigated unusual carbapenemase-producing Enterobacter cloacae complex isolates (n = 8) in the novel sequence type (ST) 873, which caused nosocomial infections in 2 hospitals in France. Whole-genome sequence typing showed the 1-year persistence of the epidemic strain, which harbored a bla_VIM-4 ST1-IncHI2 plasmid, in 1 health institution and 2 closely related strains harboring bla_CTX-M-15 in the other. These isolates formed a new subgroup in the E. hormaechei metacluster, according to their hsp60 sequences and phylogenomic analysis. The average nucleotide identities, specific biochemical properties, and pangenomic and functional investigations of isolates suggested isolates of a novel species that had acquired genes associated with adhesion and mobility. The emergence of this novel Enterobacter phylogenetic lineage within hospitals should be closely monitored because of its ability to persist and spread.

Australian infection control in endoscopy consensus statements on carbapenemase-producing Enterobacteriaceae

Outbreaks of carbapenemase-producing Enterobacteriaceae clinical infections related to endoscopic transmission are well documented. The high morbidity and mortality associated with these infections emphasizes the need to reassess endoscopic reprocessing protocols. The Gastroenterological Society of Australia established a multi-society committee to formulate evidence-based consensus statements on the prevention and management of endoscopic transmission of carbapenemase-producing Enterobacteriaceae. A literature search was undertaken utilizing the MEDLINE database. Further references were sourced from published paper bibliographies. Nine statements were formulated. Using the Delphi methodology, the statements were initially reviewed electronically by the committee members and subsequently at a face-to-face meeting in Melbourne, Australia. After further discussion, four additional sub-statements were added resulting in a total of 13 statements. Each statement was assessed for level of evidence, recommendation grade and the voting on recommendation was recorded. For a statement to be accepted, five out of six committee members had to "accept completely" or "accept with some reservation." All 13 statements achieved consensus agreement. Eleven statements achieved 100% "accepted completely." Two statements were 83% "accepted completely" and 17% "accepted with some reservation." Of particular significance, automated flexible endoscope reprocessors were mandated for high-level disinfection, and the use of forced-air drying cabinets was mandated for endoscope storage. These evidence-based statements encourage preventative strategies with the aim of ensuring the highest possible standards in flexible endoscope reprocessing thereby optimizing patient safety. They must be considered in addition to the broader published guidelines on infection control in endoscopy.

Evaluation of a novel immunochromatographic lateral flow assay for rapid detection of OXA-48, NDM, KPC and VIM carbapenemases in multidrug-resistant Enterobacteriaceae

PURPOSE

The global spread and increasing clinical impact of carbapenemase-producing bacteria are alarming. Rapid diagnostic techniques for carbapenemase detection are of the utmost importance to prevent delays in efficient antibiotic therapy and the control of spread in hospitals. Recently, multiplex immunochromatographic lateral flow tests (ICTs) for the fast detection of carbapenemase-producers have become commercially available. We evaluated a novel multiplex ICT for the rapid detection of OXA-48, KPC, NDM and VIM carbapenemases.

METHODOLOGY

One hundred well-characterized multidrug-resistant Enterobacteriaceae were analysed by RESIST-4 (Coris, BioConcept, Gembloux, Belgium). The reference standard included confirmation at the molecular level at the German National Reference Laboratory for multidrug-resistant Gram-negative bacteria (Ruhr-University Bochum, Germany).Results/Key findings. The tested ICT was highly reliable, showing 100 % sensitivity and 100 % specificity.

CONCLUSION

As it is fast, easy to perform and has few technical requirements, the ICT represents a good opportunity to improve turnaround times and patient care for the clinical microbiology laboratory.

Molecular Epidemiology and Risk Factors of Carbapenemase-Producing Enterobacteriaceae Isolates in Portuguese Hospitals: Results From European Survey on Carbapenemase-Producing Enterobacteriaceae (EuSCAPE)

In Portugal, the epidemiological stage for the spread of carbapenemase-producing Enterobacteriaceae (CPE) increased from sporadic isolates or single hospital clones (2010–2013), to hospital outbreaks, later. Here we report data from a 6-month study performed under the European Survey on Carbapenemase-Producing Enterobacteriaceae (EuSCAPE). During the study period, 67 isolates (61 Klebsiella pneumoniae and 6 Escherichia coli) non-susceptible to carbapenems were identified in participant hospital laboratories. We detected 37 bla_KPC–type (including one new variant: bla_KPC–21), 1 bla_GES–5, and 1 bla_GES–6 plus bla_KPC–3, alone or in combination with other bla genes. Bioinformatics analysis of the KPC-21-producing E. coli identified the new variant bla_KPC–21 in a 12,748 bp length plasmid. The bla_KPC–21 gene was harbored on a non-Tn4401 element, presenting upstream a partial ISKpn6 (ΔISKpn6/ΔtraN) with the related left IR (IR_L) and downstream a truncated Tn3 transposon. PFGE and MLST analysis showed an important diversity, as isolates belonged to distinct PFGE and STs profiles. In this study, we highlighted the presence of the high-risk clone E. coli sequence-type (ST) 131 clade C/H30. This worldwide disseminated E. coli lineage was already detected in Portugal among other antibiotic resistance reservoirs. This study highlights the intra- and inter-hospital spread and possible intercontinental circulation of CPE isolates.

A Large, Refractory Nosocomial Outbreak of Klebsiella pneumoniae Carbapenemase-Producing Escherichia coli Demonstrates Carbapenemase Gene Outbreaks Involving Sink Sites Require Novel Approaches to Infection Control

Carbapenem-resistant Enterobacteriaceae (CRE) represent a health threat, but effective control interventions remain unclear. Hospital wastewater sites are increasingly being highlighted as important potential reservoirs. We investigated a large Klebsiella pneumoniae carbapenemase (KPC)-producing Escherichia coli outbreak and wider CRE incidence trends in the Central Manchester University Hospital NHS Foundation Trust (CMFT) (United Kingdom) over 8 years, to determine the impact of infection prevention and control measures. Bacteriology and patient administration data (2009 to 2017) were linked, and a subset of CMFT or regional hospital KPC-producing E. coli isolates (n = 268) were sequenced. Control interventions followed international guidelines and included cohorting, rectal screening (n = 184,539 screens), environmental sampling, enhanced cleaning, and ward closure and plumbing replacement. Segmented regression of time trends for CRE detections was used to evaluate the impact of interventions on CRE incidence. Genomic analysis (n = 268 isolates) identified the spread of a KPC-producing E. coli outbreak clone (strain A, sequence type 216 [ST216]; n = 125) among patients and in the environment, particularly on 2 cardiac wards (wards 3 and 4), despite control measures. ST216 strain A had caused an antecedent outbreak and shared its KPC plasmids with other E. coli lineages and Enterobacteriaceae species. CRE acquisition incidence declined after closure of wards 3 and 4 and plumbing replacement, suggesting an environmental contribution. However, ward 3/ward 4 wastewater sites were rapidly recolonized with CRE and patient CRE acquisitions recurred, albeit at lower rates. Patient relocation and plumbing replacement were associated with control of a clonal KPC-producing E. coli outbreak; however, environmental contamination with CRE and patient CRE acquisitions recurred rapidly following this intervention. The large numbers of cases and the persistence of bla _KPC in E. coli, including pathogenic lineages, are of concern.

Genomic Characterization of Carbapenemase-Producing Klebsiella pneumoniae with Chromosomally Carried bla NDM-1

We report here Klebsiella pneumoniae strains carrying chromosomal bla _NDM-1 in Thailand. The genomes of these two isolates include a 160-kbp insertion containing bla _NDM-1, which is almost identical to that in the IncHI1B-like plasmid. Further analysis indicated that IS5-mediated intermolecular transposition and Tn3 transposase-mediated homologous recombination resulted in the integration of bla _NDM-1 into the chromosome from an IncHI1B-like plasmid. The spread of this type of carbapenem-resistant Enterobacteriaceae may threaten public health and warrants further monitoring.

Prospective evaluation of a screening algorithm for carbapenemase-producing Enterobacteriaceae

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE) have become a major public health issue. The objective of the present study was to prospectively assess the analytical performance of a CPE detection algorithm based on phenotypic tests (the screening test) and MALDI-ToF hydrolysis (the confirmatory test).

METHODS

Over a 6-month period and based on a disk diffusion method, 74 carbapenem-resistant strains were included in this study.

RESULTS

Of the collected isolates, 54 turned out to be negative after phenotypic tests. Hence, 20 strains (including all of the CPEs) were checked with the confirmation test. Seven strains were positive. After molecular biology assessments in a reference center, three of the seven were found to be false positives. The algorithm had a negative predictive value and a sensitivity of 100%, a specificity of 77%, and a positive predictive value of 20%.

CONCLUSION

The algorithm has a 24-hour turnaround time and helps to avoid using expensive molecular biology tests; we consider that it can be used on a routine basis for screening clinical strains.

Phenotypic Detection of Carbapenemase-Producing Organisms from Clinical Isolates

The rapid spread of multidrug-resistant Gram-negative organisms constitutes one of the greatest challenges to global health. While Gram-negative organisms have developed several mechanisms to avert the bactericidal effects of commonly prescribed antibiotic agents, the increasing prevalence of carbapenemase-producing organisms (CPO) is particularly concerning given the rapid spread of mobile genetic elements containing carbapenemase genes, the limited treatment options for infections caused by these organisms, and the high mortality rates associated with CPO infections. Understanding if an organism is carbapenemase producing and, if so, the class of carbapenemase(s) produced has treatment implications, as some agents preferentially have activity against specific carbapenemases. Furthermore, CPO disseminate between patients with greater ease than non-CP-carbapenem-resistant organisms and warrant more intensive infection control measures than would be employed in the absence of carbapenemase production. Phenotypic assays currently used in clinical practice to detect CPO consist of the following: (i) growth-based assays which measure carbapenem resistance based on organism growth in the presence of a carbapenem antibiotic (e.g., modified Hodge test and modified carbapenem inactivation method), (ii) hydrolysis methods which detect carbapenem degradation products (e.g., Carba NP test and matrix-assisted laser desorption-ionization time of flight mass spectrometry), and (iii) lateral flow immunoassays which detect carbapenemase enzymes through the use of specific antibodies. Although there is no single phenotypic test that meets all specifications of the ideal test, as we describe in this review, there are a number of tests that are user-friendly, affordable, accurate, and feasible for implementation in clinical microbiology laboratories of all sizes.

Ertapenem non-susceptibility and independent predictors of the carbapenemase production among the Enterobacteriaceae isolates causing intra-abdominal infections in the Asia-Pacific region: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART)

Objectives

This study investigated the prevalence rates of carbapenemase positivity, antibiotic susceptibility, and independent predictors of carbapenemase producers among the Enterobacteriaceae isolates recovered from patients with intra-abdominal infections (IAI) in the Asia-Pacific region between 2008 and 2014.

Materials and methods

Multiplex PCR was used for the detection of specific β-lactamases, while the broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of antibiotics among the IAI-related Enterobacteriaceae isolates. We studied the abovementioned parameters in 484 ertapenem-non-susceptible (Erta-NS) isolates and explored the independent predictors of carbapenemase-producing Enterobacteriaceae (CPE) isolates.

Results

Eighty (16.5%) Erta-NS-IAI Enterobacteriaceae isolates were found to be CPE. Vietnam and the Philippines had the highest CPE prevalence rates. The IAI isolates of Enterobacter species and Klebsiella pneumoniae followed by Escherichia coli were the three major pathogens with 77.4%, 40.9%, and 11.7% Erta-NS prevalence rates, respectively. Furthermore, the highest CPE prevalence (35%) was noted among the Erta-NS-K. pneumoniae isolates. The CPE isolates harboring the bla_NDM, bla_KPC, or blaOXA-48-like alleles had higher imipenem MIC levels than those harboring the bla_IMP alleles. Using multivariate logistic regression analysis, we concluded that Erta-NS-IAI isolates with an imipenem non-susceptible phenotype (OR, 56.4), with cefepime MIC >8 µg/mL (OR, 4.4), cultured from the peritoneal space samples (tissue or abscess; OR, 3.3), and harboring the extended-spectrum β-lactamase encoding allele (OR, 11.5) are independent predictors of CPE.

Conclusion

Imipenem non-susceptibility, cefepime MIC >8 µg/mL, and the peritoneal space as a culture site are independent clinical predictors of CPE among the Erta-NS-IAI Enterobacteriaceae isolates in the Asia-Pacific region.

Comparative Evaluation of Four Phenotypic Methods for Detection of Class A and B Carbapenemase-Producing Enterobacteriaceae in China

The objective of this study was to evaluate the performance of four phenotypic methods in the detection of carbapenemase-producing Enterobacteriaceae (CPE) in China. We evaluated the performance of four carbapenemase detection methods, the modified Hodge test (MHT), the Carba NP test, the meropenem hydrolysis assay (MHA) with 1- and 2-h incubation, and the modified carbapenem inactivation method (mCIM) with meropenem, imipenem, and ertapenem, on 342 carbapenem-resistant Enterobacteriaceae isolates (CRE) in China. PCR was used as the gold standard. The 2-h-incubation MHA performed the best in carbapenemase detection (overall sensitivity, specificity, positive predictive value, and negative predictive value all 100%). Second was the Carba NP test, with a sensitivity of 99.6%. The 1-h-incubation MHA performed poorly in Klebsiella pneumoniae carbapenemase (KPC) detection (sensitivity, 71.3%). For mCIM, the best performance was observed with the meropenem disk. The MHT exhibited the worst performance, with a specificity of 88.8%. All assays except 1-h-incubation MHA, which failed to identify 68 KPC-2s, had a sensitivity of >98% in the detection of 172 KPCs. Likewise, all assays had a sensitivity of >95% in the detection of 70 class B carbapenemases, except for MHT (82.9%). The 2-h-incubation MHA significantly improved the accuracy in CPE detection compared with that for 1-h incubation and performed the best in the detection of class A and B carbapenemases. Our findings suggest that the MHA is the most practical assay for carbapenemase detection. For those who cannot afford the associated equipment, both the Carba NP test and mCIM are good alternatives with regard to the practical requirements of time and cost.

MASTDISCS combi Carba plus, a simple method for discriminating carbapenemase-producing Enterobacteriaceae, including OXA-48-type producers

Accurate and rapid detection of carbapenemases and identification of their types in Enterobacteriaceae are both still major challenges for clinical laboratories in attempting to prevent the intrusion and transmission of carbapenemase-producing Enterobacteriaceae. This study aimed to evaluate the performance of the MASTDISCS combi Carba plus disc system in identification of different carbapenemase types, including OXA-48-type carbapenemase, for which no specific enzyme inhibitors have so far been available. The simple disc system discriminates carbapenemases, including OXA-48-types exhibiting low carbapenem minimum inhibitory concentrations, by targeting Enterobacteriaceae isolates with a EUCAST meropenem screening cut-off of ≥0.25 mg/L.

New Delhi Metallo-Beta-Lactamase-Producing Enterobacteriaceae in South Korea Between 2010 and 2015

This study was carried out to investigate the epidemiological time-course of New Delhi metallo-beta-lactamase- (NDM-) mediated carbapenem resistance in Enterobacteriaceae in South Korea. A total of 146 non-duplicate NDM-producing Enterobacteriaceae recovered between 2010 and 2015 were voluntarily collected from 33 general hospitals and confirmed by PCR. The species were identified by sequences of the 16S rDNA. Antimicrobial susceptibility was determined either by the disk diffusion method or by broth microdilution, and the carbapenem MICs were determined by agar dilution. Then, multilocus sequence typing and PCR-based replicon typing was carried out. Co-carried genes for drug resistance were identified by PCR and sequencing. The entire genomes of eight random selected NDM producers were sequenced. A total of 69 Klebsiella pneumoniae of 12 sequence types (STs), 34 Escherichia coli of 15 STs, 28 Enterobacter spp. (including one Enterobacter aerogenes), nine Citrobacter freundii, four Raoultella spp., and two Klebsiella oxytoca isolates produced either NDM-1 (n = 126), NDM-5 (n = 18), or NDM-7 (n = 2). The isolates co-produced CTX-M-type ESBL (52.1%), AmpCs (27.4%), additional carbapenemases (7.1%), and/or 16S rRNA methyltransferases (4.8%), resulting in multidrug-resistance (47.9%) or extensively drug-resistance (52.1%). Among plasmids harboring bla_NDM, IncX3 was predominant (77.4%), followed by the IncFII type (5.8%). Genome analysis revealed inter-species and inter-strain horizontal gene transfer of the plasmid. Both clonal dissemination and plasmid transfer contributed to the wide dissemination of NDM producers in South Korea.