Carbapenemase-producing Enterobacteriaceae Screening Research Articles

Successful control of an environmental reservoir of NDM-producing Klebsiella pneumoniae associated with nosocomial transmissions in a low-incidence setting

BackgroundThe hospital wastewater system has been reported as a source of nosocomial acquisition of carbapenemase producing Enterobacteriaceae (CPE) in various settings. Cleaning and disinfection protocols or replacement of contaminated equipment often fail to eradicate these environmental reservoirs, which can lead to long-term transmission of CPE. We report a successful multimodal approach to control a New Delhi metallo-beta-lactamase positive Klebsiella pneumoniae (NDM-KP) nosocomial outbreak implicating contamination of sink traps in a low-incidence setting.MethodsFollowing the incidental identification of NDM-KP in a urine culture of an inpatient, we performed an epidemiological investigation, including patient and environmental CPE screening, and whole genome sequencing (WGS) of strains. We also implemented multimodal infection prevention and control (IPC) measures, namely the isolation of cases, waterless patient care, replacement of contaminated P-traps and connecting pieces, and bleach and steam disinfection of sinks for 6 months, followed by patient and environmental screenings for eradication.ResultsBetween February and May 2022, five NDM-KP cases were identified in an eight-bed neurosurgical intermediate care unit. Among the eight sink traps of the unit, three were positive for NDM-KP. Patient and environmental isolates belonged to multilocus sequence typing ST-268. All isolate genomes were genetically very similar suggesting cross-transmission and a potential role of the environment as the source of transmissions. Following the introduction of combined IPC measures, no new case was subsequently detected and sink traps remained negative for NDM-KP within 6 months after the intervention.ConclusionThe implementation of multimodal IPC measures, including waterless patient care combined with the replacement and disinfection of P-traps and connecting pieces, was successful in the control of NDM-KP after eight months. In a low-incidence setting, this approach has made it possible to pursue the objective of zero transmission of carbapenemase-producing Enterobacteriaceae (CPE).

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.

1226. Two consecutive outbreaks of carbapenemase-producing enterobacteriaceae (CPE) in a pediatric hospital

Abstract Background Carbapenemase-producing enterobacteriaceae (CPE) can cause hospital outbreaks with considerable health and economic implications. Intensive infection control measures are implemented to identify CPE carriers and contain outbreaks. Methods We describe a CPE-NDM (New Delhi Metallo-beta-lactamase) hospital wide outbreak, in a tertiary care pediatric hospital, which evolved into a CPE-KPC (Klebsiella pneumoniae carbapenemase) outbreak before subsiding. Results At 10/20/21 rectal screening for CPE was performed in patients in the NICU (neonatal intensive care unit) because of known CPE carriers hospitalized there. Multiple CPE carriers were discovered, and a hospital-wide outbreak of CPE-NDM was identified. All patients who were potential contacts of CPE carriers throughout the hospital were isolated and screened twice a week, as part of intensive infection control measures. Between 10/20/21 and 12/07/21 46 patients carrying CPE-NDM were discovered. Continued screening between 12/15/21 and 04/18/22 identified 81 additional patients carrying CPE, however the carbapenemases identified in 78 of them were KPC. No known CPE-KPC carrier was hospitalized at the beginning of the KPC outbreak. Surprisingly, in 6 of the patients carrying CPE-NDM, repeat screening done months later found the carriage shifted from CPE-NDM to CPE-KPC. The results were validated and analyzed at the National Infection Control Laboratory. No significant morbidity or mortality was observed due to CPE carriage. CPE identification distribution by week and mechanism Conclusion We report an unusual sequence of two CPE outbreaks. We found no previous reports of consecutive outbreaks of CPE. Disclosures All Authors: No reported disclosures.

Audit and feedback as a tool to increase compliance with carbapenemase-producing Enterobacteriaceae (CPE) screening and decrease CPE transmission in the hospital.

To increase compliance with carbapenemase-producing Enterobacteriaceae (CPE) screening through real-time audit and feedback in our hospital and decrease CPE transmissions. A before-and-after trial, using active enhanced surveillance of CPE carriers. A 500-bed, secondary, university-affiliated hospital that serves a population of 450,000 in a northern district in Israel. The study was conducted during 2016-2019 and included patients who were admitted to the hospital and fulfilled CPE screening criteria upon admission and during prolonged hospitalizations. On January 1, 2017, the infection control team implemented a new strategy of real-time feedback toward compliance with in-hospital screening guidelines. Other infection control measurements were performed without interventions. The primary outcome was compliance with appropriate CPE screening. Secondary outcomes included CPE acquisition and compliance with hand hygiene and contact precaution practices. Data were analyzed to calculate differences between compliance with CPE screening during the study period and to test the correlation between contact precautions and hand hygiene practices according to compliance with CPE screening. During the study period, 3,131 patients were eligible for CPE screening. We detected a statistically significant increase in compliance to CPE screening from 74% during 2017 to 92% in 2018 and 95% in 2019 (P < .0001 for both comparisons). We detected a decrease in CPE transmission from 12% in 2017 to 2% in 2019 (P < .0001). We did not find any correlation between other infection control interventions and CPE screening and acquisition. Audit and feedback can improve appropriate CPE screening and may reduce CPE transmission in the hospital.

Importance of the Respiratory Tract in Carbapenemase-Producing Enterobacteriaceae Spread

Background: Carbapenemase-producing Enterobacteriaceae (CPE) causes infections associated with high mortality rates among hospitalized patients. CPE transmission occurs frequently, and prevention of patient-to-patient transmission is a priority. However, transmission pathways are not yet completely understood. The colonization of the respiratory tract with a CPE may lead to a higher risk of contamination of the patient’s environment increasing the spread of CPE. Objective: We estimated the rate of CPE spread when respiratory tract infection or colonization is present. Methods: We studied CPE dissemination analyzing a cohort of patients admitted between January 2013 and December 2018 at the university hospital complex of A Corua, a tertiary-care hospital. All patients who were hospitalized in the same room as a patient colonized or infected with a CPE (index case) for at least 24 hours were screened for CPE carriage. The microbiological screening was performed with conventional culture or polymerase chain reaction (PCR) to identified possible CPE patient-to-patient transmission. The screening test included several samples: rectal swab, perineal swab, wound or drainage swab, and low respiratory tract sample. Results: Active screening for CPE carriage was performed in 84 contact patients. Men represent 57.1% of the sample, and the mean age was 78.5 years (men, 68.0 years and women, 80.8 years), with significant differences between sexes (12.9; 95% CI, 19.6 to 6.1). The major group of cases (86.9%) were hospitalized in medical wards. Transmission confirmed by PCR occurred in 13 (15.5%) of 84 contact patients, after a mean exposure to the index case of 13.3 days. No significant differences were detected in terms of mean exposure to index cases between those contact patients who result negative and those who result positive. The 35 index cases (41.7%) tested positive for CPE on the respiratory sample, and exposure to them led to 8 positive contact patients (61.5%). Conclusions: CPE transmission in a tertiary-care hospital occurred frequently. The spread rate is even higher when CPE is present at the respiratory level. Understanding the mode of spread is important for designing effective control measures and adding a respiratory sample to CPE screening could be a key consideration.Funding: NoneDisclosures: None

Epidemiology and control measures of an OXA-48-producing Enterobacteriaceae hospital outbreak

SummaryCarbapenemase-producing Enterobacteriaceae (CPE) are a significant challenge to healthcare and infection prevention and control teams. In the UK, OXA-48-like carbapenemases are frequently reported. We describe an outbreak of OXA-48-like producing Enterobacteriaceae and the control measures that proved effective in containing further spread.AimTo describe epidemiologic and laboratory features of outbreak and highlight key control interventions.FindingsFollowing the introduction of an increased sensitivity CPE screening protocol, OXA-48-like CPE were identified in screening and clinical samples from 96 patients across five hospital wards between November 2017 and July 2018. Klebsiella pneumoniae and Enterobacter cloacae were the most frequently isolated organisms, although a range of OXA-48-like positive organisms were identified. The outbreak was contained utilising certain key interventions, including the modification of laboratory screening processes, engagement of hospital senior management, clear and frequent communication and a strong ‘ward presence’ by the infection prevention and control team (IPCT).ConclusionOur report describes how a change in laboratory CPE screening process unmasked a CPE outbreak. The range of bacterial species harbouring the OXA-48-like mechanism suggested plasmid-mediated transfer of resistance. The timely implementation of interventions using a clinical, ‘ward-based’ approach to infection prevention and control highlights the importance of behavioural change in infection control interventions and enabled the termination of a large outbreak without recourse to environmental sampling, major remedial construction work or extensive molecular strain or plasmid typing.

Towards a harmonised approach to Carbapenemase-producing Enterobacteriaceae (CPE) screening and patient management in North East and Cumbria hospitals

In mid-2018, a Carbapenemase-producing Enterobacteriaceae (CPE) cluster was investigated in the North East of England, in which transmission had occurred across several hospital trusts. We undertook a survey of current CPE detection and management practices in North East and Cumbria (NEC) trusts to inform a harmonised approach that could be adopted across the region. A semi-structured survey was carried out with one consultant microbiologist per trust by telephone interview (n=6) or electronic questionnaire (n=3) to determine CPE screening procedures, laboratory techniques and patient management practices. Screening policies were in place in all trusts, including screening protocols for patients previously admitted outside of the UK or those known to be CPE positive, in accordance with PHE guidelines. Policies for screening patients who had been admitted to other UK hospitals varied across trusts, as did laboratory methods used. Over 80% of trusts communicated CPE status to patients and contacts by information leaflet. However, there was no uniform way of communicating CPE status to social care settings, GPs and other hospital trusts in the event of discharge or inter-hospital transfer. The results of the survey suggest improvements could be made to the way information on patient CPE status is shared to ensure that the risk of transmission is reduced. This includes improved communication with residential settings, primary care and other hospital trusts in the event of a discharge or inter-hospital transfer. In addition, this work will inform further discussions across NEC towards developing a single regional Infection Prevention and control strategy for CPE.

534. Active Screening for Carbapenemase Producing Enterobacteriaceae: Yield and Cost Considerations

BackgroundDuring 2016, our hospital experienced an outbreak with carbapenemase-producing Enterobacteriaceae (CPE) in our solid-organ transplant (SOT) population. Since this outbreak and until now, our hospital has implemented active CPE screening of patients admitted to SOT units and point prevalence surveillances in any unit with a known CPE patient. The present study evaluates the yield of these screening tests and their cost since implementation.MethodsThis retrospective cohort was performed in a 600-bed hospital in Milwaukee, WI. CPE screening tests were retrieved from the clinical microbiology laboratory dataset from January 2016 to April 2019. CPE tests are performed on rectal swabs or stool samples using the CDC broth enrichment method followed by MIC confirmation using Etest. CPE patients were placed on enhanced precautions (gowns, gloves, booties) and were cohorted geographically and to 1:1 nursing and nurse aid staff.ResultsA total of 6,684 samples belonging to 3,383 patients were processed (1.9 samples/patient). Two hundred thirty (3.44%) had carbapenem-resistant Enterobacteriaceae, although only 33 isolates (0.49%) were confirmed as either KPC (n = 31) or NDM (n = 2) positive. Out of the 3,383 patients tested, 121 were identified as carriers of carbapenem-resistant isolates but only 11 (0.32%) were CPE (KPC = 11; NDM = 2). The incidence of new CPE patients during 2016 was 0.82% but decreased to 0.28% and 0.33% in 2017 and 2018, respectively. The units with the highest number of CPE patients were the transplant intensive care unit (n = 6) and the step-down SOT unit (n = 3). Negative cultures were quoted at $8.49 per sample but culture plates with colonies increased the cost per test to $28.44. The total cost for all the 6,684 screening tests was calculated at $61,335. The cost of CPE screening per positive CPE patient identified comes up to $5,575 (not including RN collection time).ConclusionIn an institution with staff and CPE patient cohorting, active screening of CPE positive patients was relatively expensive given our low -level of transmission. In the near future, we plan to stop staff and patient cohorting due to the high stress that these interventions place on our hospital staff. This might ensue in increase transmission, which will be detected by CPE screening tests.Disclosures All authors: No reported disclosures.

530. Sequential Screening of High-Risk Patients for Carbapenemase-Producing Enterobacteriaceae Colonization

BackgroundEarly identification of patients colonized with carbapenemase-producing Enterobacteriaceae (CPE) facilitates the implementation of appropriate infection control measures and reduces nosocomial transmission. Sequential screening for CPE colonization of close contacts of known cases to confirm initial negative results is recommended. Fraser Health (FH) expanded sequential screening to patients with recent exposure to other risk factors following the identification of CPE in patients who initially screened negative.MethodsFH screens patients for CPE who report healthcare outside of Canada or travel to endemic countries within the previous 12 months. Patients remain on contact precautions and are re-screened 7 and 21 days after the last known exposure date. We reviewed CPE cases with foreign healthcare or travel to endemic countries who screened negative on admission but subsequently screened positive within 30 days. Patients without confirmation of colonization through a rectal screen or possible exposure to a current nosocomial source were excluded. Whole-genome sequencing results were examined to confirm foreign healthcare or travel as the likely source of acquisition. Medical records were reviewed to obtain patient history and clinical details.ResultsBetween November 2015 and January 2019, 21 patients had a positive CPE screen within 30 days of a negative screen, with no known CPE exposures during that time. The median time between the last date of known exposure and positive CPE screen was 20 days (range: 7–77 days). Twelve (57%) cases were hospitalized outside of Canada, 8 (38%) reported other foreign healthcare encounters, and 1 (5%) had no reported healthcare outside of Canada but had traveled to an endemic country. Sixteen (71%) cases received antibiotics prior to the positive CPE screen.ConclusionPatients with unrecognized CPE colonization are a source for nosocomial transmission. Patients screening negative for CPE with recent exposure to risk factors other than contact with a known case may screen positive at a later date. This may be due to higher colonization levels or antibiotic selection pressures. Consideration should be given to sequential CPE screening of high-risk patients based on the last day of exposure.Disclosures All authors: No reported disclosures.

Rectal screening for carbapenemase-producing Enterobacteriaceae: a proposed workflow

ObjectivesActive screening is a crucial element for the prevention of carbapenemase-producing Enterobacteriaceae (CPE) transmission in healthcare settings. Here we propose a culture-based protocol for rectal swab CPE screening that combines CPE detection with identification of the carbapenemase type. MethodsThe workflow integrates an automatic digital analysis of selective chromogenic media (WASPLab®; Copan), with subsequent rapid tests for the confirmation of carbapenemase production [i.e. detection of Klebsiella pneumoniae carbapenemase (KPC)-specific peak by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS) or a multiplex immunochromatographic assay identifying the five commonest carbapenemase types]. To evaluate the performance of this protocol in depth, data for 21 162 rectal swabs submitted for CPE screening to the Microbiology Unit of S. Orsola-Malpighi Hospital (Bologna, Italy) were analysed. ResultsConsidering its ability to correctly segregate plates with/without Enterobacteriaceae, WASPLab Image Analysis Software showed globally a sensitivity and specificity of 100% and 79.4%, respectively. Of the plates with bacterial growth (n = 901), 693 (76.9%) were found to be positive for CPE by MALDI-TOF/MS (KPC-specific peak for K. pneumoniae) or by immunochromatographic assay. Only 2.8% (16/570) of KPC-positive K. pneumoniae strains were missed by the specific MALDI-TOF/MS algorithm, being detected by the immunochromatographic assay. The mean turnaround time needed from sample arrival to the final report ranged between 18 and 24 h, representing a significant time saving compared with manual reading. ConclusionThis workflow proved to be fast and reliable, being particularly suitable for areas endemic for KPC-producing K. pneumoniae and for high-throughput laboratories.

Detection of meticillin-resistant Staphylococcus aureus and carbapenemase-producing Enterobacteriaceae in Danish emergency departments – evaluation of national screening guidelines

Multi-resistant bacteria (MRB) are an emerging problem. Early identification of patients colonized with MRB is mandatory to avoid in-hospital transmission and to target antibiotic treatment. Since most patients pass through specialized emergency departments (EDs), these departments are crucial in early identification. The Danish National Board of Health (DNBH) has developed exposure-based targeted screening tools to identify and isolate carriers of meticillin-resistant Staphylococcus aureus (MRSA) and carbapenemase-producing Enterobacteriaceae (CPE). To assess the national screening tools for detection of MRSA and CPE carriage in a cohort of acute patients. The objectives were to investigate: (i) if the colonized patients were detected; and (ii) if the colonized patients were isolated. This was a multi-centre cross-sectional survey of adults visiting EDs. The patients answered the DNBH questions, and swabs were taken from the nose, throat and rectum. The collected samples were examined for MRSA and CPE. Screening performances were calculated. Of the 5117 included patients, 16 were colonized with MRSA and four were colonized with CPE. The MRSA screening tool had sensitivity of 50% [95% confidence interval (CI) 25-75%] for carrier detection and 25% (95% CI 7-52%) for carrier isolation. The CPE screening tool had sensitivity of 25% (95% CI 1-81%) and none of the CPE carriers were isolated. The national screening tools were of limited use as the majority of MRSA and CPE carriers passed unidentified through the EDs, and many patients were isolated unnecessarily.

Screening for carbapenemase-producing Enterobacteriaceae in previous carriers readmitted to hospital: evaluation of a change in screening policy

Carbapenemase-producing Enterobacteriaceae (CPE) are a growing problem in UK hospitals. Preventing transmission requires early detection. This study evaluates a new screening policy for patients with a history of blaKPC-associated CPE (KPC-CPE) in a higher incidence hospital. Previous policy assumed 'once positive always positive'. New policy uses rapid screening and risk assessment. Results show that most (76.5%) patients with a history of KPC-CPE do not have detectable KPC-CPE on readmission or during their subsequent hospital stay but that repeat screening after an initial negative result is required. The new policy takes a risk-based approach while prioritizing isolation facilities in a higher incidence trust.

The acceptability of screening for Carbapenemase Producing Enterobacteriaceae (CPE): cross-sectional survey of nursing staff and the general publics’ perceptions

BackgroundCarbapenemase Producing Enterobacteriaceae (CPE) has spread rapidly and presents a growing challenge in antimicrobial resistance (AMR) management internationally. Screening for CPE may involve a rectal swab, there are limited treatment options for affected patients, and colonised patients are cared for in isolation to protect others. These measures are sound infection prevention precautions; however, the acceptability of CPE screening and its consequences are currently unknown.The aim of this study was ‘To determine factors influencing acceptability of CPE screening from the perspectives of nursing staff and the general public.’MethodsNational cross-sectional surveys of nursing staff (n = 450) and the general public (n = 261). The Theoretical Domains Framework (TDF) guided data collection and analysis. Regression modelling was used to identify factors that predicted acceptability of CPE screening.ResultsFor nursing staff, the following predictor variables were significant: intention to conduct CPE screening (OR 14.19, CI 5.14–39.22); belief in the severity of the consequences of CPE (OR 7.13, CI 3.26–15.60); knowledge of hospital policy for screening (OR 3.04, CI 1.45–6.34); preference to ask patients to take their own rectal swab (OR 2.89, CI 1.39–6.0); awareness that CPE is an organism of growing concern (OR 2.44, CI 1.22–4.88). The following predictor variables were significant for the general public: lack of knowledge of AMR (β − .11, p = .01); social influences (β .14,p = .032); social norms (β .21p = .00); acceptability of being isolated if colonised (β .22, p = .000), beliefs about the acceptability of rectal swabbing (β .15, p = .00), beliefs about the impact of careful explanation about CPE screening from a health professional (β .32, p = .00).Integrating results from staff and public perspectives points to the importance of knowledge of AMR, environmental resources, and social influences in shaping acceptability.ConclusionsThis is the first study to systematically examine the acceptability of CPE screening across nursing staff and the public. The use of TDF enabled identification of the mechanisms of action, or theoretical constructs, likely to be important in understanding and changing CPE related behaviour amongst professionals and public alike.

Screening for carbapenemase-producing enterobacteriaceae following transmission: Experience at a large victorian healthcare facility

Screening for carbapenemase-producing enterobacteriaceae following transmission: Experience at a large victorian healthcare facility

Epidemiology of carbapenem-resistant Enterobacteriaceae (CRE) and comparison of the phenotypic versus genotypic screening tests for the detection of carbapenemases at a tertiary level, academic hospital in Johannesburg, South Africa

Background: Carbapenem-resistant Enterobacteriaceae (CRE) cause significant infections and pose a threat to the viability of available antibiotics. Understanding the epidemiology of these infections will assist in guiding appropriate treatment and infection prevention and control (IPC) practices in an institution. In addition, the phenotypic carbapenemase-producing Enterobacteriaceae (CPE) screening tests are widely used in South Africa. However, there is no published literature on their performance against PCR in that setting. Therefore, CRE epidemiology and performance of the Modified Hodge with Imipenem and Imipenem + EDTA combined disk tests (CDT) was evaluated at a tertiary academic hospital in Johannesburg.Method: A retrospective collection of data was performed. Data from January 2015 to December 2016 of all clinical isolates that were CRE OR carbapenem-susceptible Enterobacteriaceae with at least one positive CPE screening test were collected. Information collected included the ward areas from which samples were sent, specimen type that cultured CRE, CRE identification and carbapenem MIC results, phenotypic and genotypic CPE results.Results: Certain ward areas recurred as predominant areas with CRE infection in the two-year period. The prominent sample types that cultured CRE, the predominant Enterobacteriaceae species and carbapenemases identified corresponded with national surveillance data. The predominant carbapenemase type and level of carbapenem resistance conferred changed within one year. The Hodge test performed poorly for carbapenemase detection. The CDT detected metallo-β-lactamases adequately.Conclusion: In this study, the use of the MHT to screen for CPEs performed poorly. Continued surveillance will (i) lead to an understanding of the patient population (including infection type) affected, (ii) detect changes in the carbapenemase profiles, and (iii) inform infection prevention and control and appropriate clinical management.

Point-prevalence survey of carbapenemase-producing Enterobacteriaceae and vancomycin-resistant enterococci in adult inpatients in a university teaching hospital in the UK

Infections with carbapenemase-producing Enterobacteriaceae (CPE) and vancomycin-resistant enterococci (VRE) are associated with increased morbidity and mortality, but the carriage rates of CRE and VRE among hospital inpatients are unknown. A point-prevalence survey was conducted to determine CPE and VRE carriage rates in hospitalized adults. Eight hundred and eighteen of 960 (85.2%) adult inpatients were invited to participate in the study. Of these, 595 patients (72.7%) consented and provided specimens. Of 540 samples tested, none were positive for CPE. One hundred and thirty of 540 (24.1%) samples were VRE positive, and 34 of 40 (85%) of wards had cases. Universal screening for CPE may not be cost-effective in low-prevalence settings, but targeted screening of high-risk patients should continue. The optimal screening strategy for VRE remains to be determined, as universal screening and isolation is not feasible in the study setting.

Phenotypic and genotypic correlation of carbapenememase-producing Enterobacteriaceae and problems experienced in routine screening.

The emergence and transmission of carbapenem-resistant Enterobacteriaceae (CRE) is a concern in both the clinical and public health arenas. Reliable and accurate detection of these organisms is required for patient management and infection prevention and control purposes. In the routine laboratory, phenotypic methods are utilised for identification of CRE. To investigate the phenotypic profiles of suspected carbapenemase-producing Enterobacteriaceae (CPE) isolates generated by the automated MicroScan Walkaway system making use of the Clinical and Laboratory Standards Institute (CLSI) guidelines, and correlate these with carbapenemase production by molecular methods. Antimicrobial susceptibility testing was performed using the MicroScan Walkaway system, and the presence of six carbapenemase genes (blaNDM, blaVIM, blaIMP, blaOXA-48and variants, blaGESand blaKPC) was screened for using a multiplex real-time polymerase chain reaction. A total of 2 678 isolates were evaluated. Klebsiella pneumoniae accounted for 62.9% of the isolates (n=1 685), followed by Enterobacter cloacae (n=361, 13.5%). Carbapenemases accounted for 75.2% of isolates; blaOXA-48 and its variants predominated (n=978, 36.5%), followed by blaNDM (n=904, 33.8%), blaVIM (n=108, 4.0%), blaIMP (n=35, 1.3%), blaGES (n=24, 0.9%) and blaKPC (n=18, 0.7 %). A considerable number of isolates expressing a carbapenemase or carbapenemases (the majority of which were blaOXA-48 producing) were susceptible to third-and fourth-generation cephalosporins and carbapenems, demonstrating that confirmed carbapenemase-producing isolates are not presenting as possible carriers of carbapenemases using routine diagnostic methods. Similar results were obtained when CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints were applied and are suitable for the purpose of patient management. However, since genotyping assays are costly, it is suggested that routine laboratories first perform comprehensive phenotypic screening for CPE.

Evaluation of the Carbapenem Detection Set™ for the detection and characterization of carbapenemase-producing Enterobacteriaceae

The objective of this study was to assess the performance of the Carbapenemase Detection Set™ (CDS; Mast Diagnostics) in association with i) the EUCAST meropenem screening cut-off and ii) the faropenem–temocillin algorithm (FTa) for the screening of carbapenemase-producing Enterobacteriaceae (CPE). A total of 200 well-characterized enterobacterial isolates with reduced susceptibility to at least one carbapenem including 63 non-CPEs and 137 CPEs belonging to different Ambler classes were initially screened for CPEs using i) the EUCAST meropenem cut-off (diameter <25 mm) and ii) the FTa. Highly suspected CPEs underwent further testing using the CDS, which is based on the inhibition zone diameters determination of combined disks (A: meropenem, B: meropenem + dipicolinic acid, C: meropenem + cloxacillin, and D: meropenem + boronic acid). With the FTa, 66.7% of the non-CPE isolates were correctly identified. Most OXA-48-like producers (90.5%) were detected with 98.6% specificity. The FTa discriminates CPE from non-CPE with 100% sensitivity, but complementary tests were still needed for 59 % (118/200) of the strains. The EUCAST cut-off led to 3 false-negative results (2 OXA-181 and 1 NMC-A producer) resulting in a sensitivity of 97.8% for the discrimination between CPE and non-CPE, and 75.5% (151/200) of the strains still required complementary test. The CDS reduced the number of isolates requiring additional tests from 59% to 22%, and from 75.5% to 38% for FTa and EUCAST cut-off, respectively. FTa possesses very good specificities for the detection and classification of Ambler class A and most class B carbapenemase-producers, except for IMP producers, which were almost not detected (10/11). In conclusion, the association of the CDS with the FTa presented only 22% of inconclusive results, while this number was 38% with the EUCAST meropenem CPE screening cut-off.

Recommendations for the control of carbapenemase-producing Enterobacteriaceae (CPE): A guide for acute care health facilities

Gram-negative bacteria that are resistant to antimicrobials, including carbapenems, have emerged as a significant global public health threat. Multidrug-resistant gram-negative bacteria, including carbapenemase-producing Enterobacteriaceae (CPE), place patients at risk of potentially untreatable infection. Australia has not reported a large number of CPE cases compared to Europe, North America, and the Middle East, creating an opportunity to prevent CPE from becoming established in Australia.An outbreak of Klebsiella pneumoniae carbapenemase in 2014 demonstrated there was variable testing, reporting, response to and communication of CPE. In response, the Australian Commission on Safety and Quality in Health Care formed a taskforce to assist health facilities to respond to the threat of CPE. Recommendations for state and territory health departments include coordinating a risk assessment, undertaking epidemiological and microbiological investigations, determining the requirement for control measures, and coordinating risk-communication activities. The response should take advice from experts in infectious diseases, microbiology, public health, infection prevention and control and epidemiologists.The guide aims to:•Alert healthcare professionals, health departments and hospital executives to the emerging threat of CPE in Australia•Recommend strategies to prevent, detect and contain CPE•Provide information and resources for hospital executives, healthcare professionals and consumers•Recommend laboratory screening and confirmation methods.The recommendations with rationale and commentary have been structured into sections depending on the burden of CPE in the health facility. The sections include: planning, preparing and prevention; CPE screening and surveillance; strategies to reduce CPE transmission; outbreak management; laboratory screening and confirmation methods.

Optimal detection of carbapenemase-producing Enterobacteriaceae from rectal samples: a role for enrichment?

Successful laboratory detection of carbapenemase-producing Enterobacteriaceae (CPE) in patient surveillance samples is a diagnostic challenge. In the absence of a reference standard for screening rectal swabs for CPE, many phenotypic, genotypic, culture- and non-culture-based assays have been proposed for identifying these bacteria. To develop and optimize a CPE screening protocol capable of identifying all frequently encountered CPE, including those producing OXA-48-like carbapenemases. Faropenem susceptibility testing was performed on 507 presumptive CPE isolated from diagnostic samples and CPE rectal screens between March and August 2016. Results from this CPE screening method were compared to those from direct culture on mSuperCARBA™, temocillin enrichment culture, and use of an antibiotic resistance algorithm, to determine the optimal method to employ in the detection of CPE. Faropenem was a poor predictor of carbapenemase production (58% true positives). The combination of a temocillin enrichment stage and interpretive reading of antibiotic resistance phenotypes improved the recovery and identification of CPE significantly (91% true positives), especially for OXA-48 producers (P=0.03). The combination of temocillin enrichment, a selective chromogenic medium, and an antibiotic resistance-based algorithm significantly improved the detection of all CPE recovered from routine and targeted surveillance samples.