Detection Of Carbapenemase-producing Enterobacteriaceae Research Articles

Infection due to travel-related carbapenemase-producing Enterobacteriaceae, a largely underestimated phenomenon in Belgium

Background:Carbapenemase-producing Enterobacteriaceae (CPE) are emerging worldwide, representing a major threat for public health. Early CPE detection is crucial in order to prevent infections and the development of reservoirs/outbreaks in hospitals. In 2008, most of the CPE strains reported in Belgium were imported from patients repatriated from abroad. Actually, this is no longer the case.Objectives and methods:A surveillance was set up in Belgian hospitals (2012) in order to explore the epidemiology and determinants of CPE, including the link with international travel/hospitalization. The present article describes travel-related CPE reported in Belgium. Different other potential sources for importation of CPE are discussed.Results:Only 12% of all CPE cases reported in Belgium (2012–2013) were travel related (with/without hospitalization). This is undoubtedly an underestimation (missing travel data: 36%), considering the increasing tourism, the immigration from endemic countries, the growing number of foreign patients using scheduled medical care in Belgium, and the medical repatriations from foreign hospitals. The free movement of persons and services (European Union) contributes to an increase in foreign healthcare workers (HCW) in Belgian hospitals. Residents from nursing homes located at the country borders can be another potential source of dissemination of CPE between countries. Moreover, the high population density in Belgium can increase the risk for CPE-dissemination. Urban areas in Belgium may cumulate these potential risk factors for import/dissemination of CPE.Conclusions:Ideally, travel history data should be obtained from hospital hygiene teams, not from the microbiological laboratory. Patients who received medical care abroad (whatever the country) should be screened for CPE at admission.

Global dissemination of extensively drug-resistant carbapenemase-producing Enterobacteriaceae: clinical perspectives on detection, treatment and infection control.

The prevalence of carbapenem-resistant Gram-negative bacilli is on the rise worldwide, posing a major public health threat. Previously, this was mostly a problem in Pseudomonas and Acinetobacter, but during the last decade, carbapenem resistance has escalated in medically important species such as Klebsiella pneumoniae and Escherichia coli. In particular, the rising trend in E.coli is of concern, as this may lead to almost untreatable community-acquired infections. Resistance is conferred by carbapenemases, which are beta-lactamases that can breakdown essentially all beta-lactams. Moreover, bacteria carrying these resistance determinants are often resistant to other treatment options, due to the frequent co-acquisition of non-beta-lactam resistance genes located on the same mobile genetic elements. The detection of carbapenemase-producing Enterobacteriaceae (CPE) is a challenge, because some carbapenemases produce relatively discrete levels of carbapenem resistance. Current clinical evidence for treatment guidance is limited and based on retrospective observational studies and case reports. Existing data support the use of combination therapy for treatment of severe infections caused by CPE. Combination regimens including colistin, carbapenems, tigecycline, aminoglycosides and fosfomycin have been used. Randomized controlled studies of combination regimens are ongoing and may help to determine the optimal therapy. Novel beta-lactamase inhibitors may also have a role in future treatment of these infections. Strict infection control measures including isolation or cohort care of affected patients as well as contact tracing and active screening are needed to curb the spread of CPE. In this review, we provide a clinical perspective on the management of patients infected or colonized with CPE.

Epidemiology of Carbapenem Resistance among Multi-drug Resistant Enterobacteriaceae in Uganda.

BackgroundMulti-drug resistant (MDR) Enterobacteriaceae are on the increase worldwide and their spread has become a global challenge. Escalating the challenge is the possibility that many of these are Carbapenemase-producing Enterobacteriaceae (CPE). This further complicates patient management. The magnitude of MDR-CPE in many developed settings has been reported, however, there is paucity of data from resource limited settings. We evaluated the epidemiology of MDR-CPE of clinical origin in South Western Uganda.MethodsFrom September 2013 to June 2014, all Enterobacteriaceae isolated from diverse specimens obtained from patients attending Mbarara Regional Referral Hospital, South-western Uganda, were screened for MDR in a laboratory-based cross sectional study. Isolates found to be MDR were screened for carbapenem susceptibility/resistance phenotypically by Kirby Bauer disc diffusion method following CLSI guidelines and genetically using the multiplex real-time Polymerase Chain Reaction (RT-PCR).ResultsOf the 658 strains isolated, 183 (27.8%) were MDR and 68 (37.15%) of those MDR exhibited at least one form of carbapenem resistance with 23 (12.57%) and 56 (30.60%) isolates expressing phenotypic and genetic resistance, respectively. Eleven MDR-CPE (6.01%) isolates exhibited both phenotypic and genotypic resistance to carbapenems. Only blaVIM and blaOXA-48 genes were detected among the genetically resistant isolates.ConclusionThe high prevalence of MDR-CPE calls for aggressive infection control and prevention strategies, including reinforcement of hand hygiene, using contact precautions and early detection of CPE through use of targeted surveillance and molecular techniques in resource limited settings.

Detection of carbapenemase-producing Enterobacteriaceae in various scenarios and health settings

Detection of carbapenemase-producing Enterobacteriaceae (CPE) is an important task at microbiology laboratories in hospitals. As the prevalence of CPE is increasing worldwide, the implementation of phenotypically based screening as well as confirmatory procedures to detect CPE are important for microbiologists. In addition to detection of carbapenem hydrolysis, the inhibition of activity against a carbapenem in the presence of several inhibitor compounds specific to class A, B, or class C beta-lactamases is a useful method to confirm the presence of carbapenemases in bacterial isolates. There is also a proteomic approach that compares the MALDI-TOF spectrum generated by the intact carbapenem (non-hydrolyzed) with that obtained after hydrolysis of the beta-lactam ring by beta-lactamase to reveal the presence of carbapenemases in bacterial isolates. Proteomic methods will probably be more frequently implemented in laboratories in the near future. Finally, molecular methods to directly or indirectly detect the presence of a carbapenemase genes are increasingly being used in microbiology laboratories. One of the main advantages of these methods is their speed, and also that they can be used directly with the clinical sample without the need for an isolated bacterial colony. Multiplex PCR, real-time PCR, DNA microarrays and pyrosequencing are some examples of molecular-based tests. Their main disadvantage is their cost, although prices are going down as the range of services increases. Surveillance of carriers is also an important task for infection control purposes. In this case, commercially available chromogenic medium supplemented with low carbapenem concentrations has shown an excellent ability to detect CPE. Moreover, molecular methods to detect specific carbapenemase genes directly from rectal swabs, stools, or other colonization sources have had excellent results.

The occurrence of Enterobacteriaceae producing KPC carbapenemases in a general hospital in Curacao.

BackgroundAlthough the presence of Carbapenemase-producing Enterobacteriaceae (CPE) are extensively documented in North and South America. CPE have not been reported from Curacao. However, recently intercontinental spread was suggested of a KPC carbapenemase producing Klebsiella pneumoniae in a patient in the United Kingdom with previous admission to a hospital in Curacao in 2009.FindingsAfter the introduction of the CLSI 2010 revised breakpoints, seven patients with carbapenemase-producing Enterobacteriaceae were found in a general hospital in Curacao over a period of 16 months. Four patients carried KPC-2 positive Klebsiella pneumoniae, ST11. Two patients carried KPC-3 positive Klebsiella pneumoniae ST258 and one patient carried a KPC-3 positive Citrobacter freundii. Furthermore, our Klebsiella pneumoniae KPC-2 ST11 strain was matched to the Klebsiella pneumoniae KPC-2 ST11 strain in the United Kingdom.ConclusionsIntroduction of new laboratory methods, and adoption of new guidelines and breakpoints led to the first detection of CPE in Curacao. By matching our Klebsiella pneumoniae KPC-2 ST11 strain to a Klebsiella pneumoniae KPC-2 ST11 strain in the United Kingdom, we suggest that carbapenemase-producing Enterobacteriaceae are probably more prevalent in Curacao than previously recognized.

Comparison of phenotypic methods for the detection of IMP producing enterobacteriaceae in queensland

Background The prevalence of carbapenemase producing enterobacteriaceae (CPE), particularly IMP producers (IMP), in Australia is increasing. Optimal methods for detection of IMP CPE are unknown. We compare six phenotypic methods to determine the most sensitive method for the detection of IMP CPE. Methods We tested 25 molecularly confirmed IMP CPE producers, including 16 Enterobacter cloacae , collected from Queensland Health hospitals. The following methods were performed: disc susceptibility testing (DST), minimum inhibitory concentrations (MICs) by E-test, broth microdilution (BMD) and Vitek 2, modified hodge test (MHT) and Carba NP test. Results Meropenem MIC range (MIC 50/90 ) was 0.25->32 (4/16), 0.25-32(2/16), 1->16(>16/>16) for BMD, E-test and Vitek 2, respectively. Seventeen percent of isolates had a Vitek 2 meropenem MIC between 1-2 |xg/mL. Using EUCAST breakpoints, all isolates tested resistant by Ertapenem E-test and all except for one isolate was resistant by ertapenem DST. CLSI breakpoints increased detection of CPE with meropenem and imipenem. Carba NP test and MHT provided positive results for all isolates. Conclusion: Our results indicate that isolates with a Vitek 2 meropenem MIC of ≥1 μg/mL should undergo further phenotypic testing. Ertapenem DST, ertapenem E-test, Carba NP test and MHT are the most sensitive methods for detection of IMP CPE.

Temocillin and piperacillin/tazobactam resistance by disc diffusion as antimicrobial surrogate markers for the detection of carbapenemase-producing Enterobacteriaceae in geographical areas with a high prevalence of OXA-48 producers

To assess the performance of the agar disc diffusion method for the detection of carbapenemase-producing Enterobacteriaceae (CPE) referred to the national reference laboratories (NRLs) in Belgium and France. All Enterobacteriaceae isolates referred to the NRLs for the confirmation of CPE in 2012 were included. The inhibition zone diameters of meropenem, piperacillin/tazobactam and temocillin using CLSI disc diffusion methodology were recorded. Phenotypic and molecular detection of carbapenemases was performed on all isolates. A total of 1354 Enterobacteriaceae isolates, including 435 (32.1%) confirmed CPE isolates [OXA-48 (n = 323), KPC (n = 60), VIM (n = 32) and NDM (n = 20)] and 919 carbapenemase-negative isolates, were tested. Using recommended interpretative criteria, non-susceptibility to meropenem had poor sensitivity (52.0% by CLSI susceptibility breakpoint and 80.0% by EUCAST screening breakpoints), while non-susceptibility to piperacillin/tazobactam (according to CLSI breakpoint) or to temocillin (according to Fuchs, Barry, Thornsberry et al. Eur J Clin Microbiol 1985; 4: 30-3) was highly sensitive (99.8% and 98.2%, respectively) but poorly specific (29.4% and 42.9%, respectively) for the detection of CPE. Temocillin diameters <12 mm alone had high specificity (90.0%) and the combination of temocillin diameters ≥12 mm with piperacillin/tazobactam diameters ≥16 mm observed in 40% of all referred isolates displayed excellent negative predictive value (99.2%). In geographical areas with a high prevalence of OXA-48 producers, recommended meropenem susceptibility or screening breakpoints failed to detect CPE in a large proportion of isolates. The combination of modified zone diameter cut-offs for piperacillin/tazobactam (≥16 mm) and temocillin (≥12 mm) can be used to rule out the presence of carbapenemase and avoid unnecessary additional testing for confirmation of CPE.

Evaluation of the Oxoid Brilliance™ CRE Agar for the detection of carbapenemase-producing Enterobacteriaceae

The adequate detection of carbapenemase-producing Enterobacteriaceae (CPE) is essential for adequate antibiotic therapy and for infection control purposes, especially in an outbreak setting. Selective agars play an important role in the detection of CPE. The Oxoid Brilliance™ CRE Agar (Thermo Fisher Scientific) was evaluated for the detection of CPE using 255 non-repetitive Enterobacteriaceae isolates, including 95 CPE (36 KPC, 4 KPC plus VIM, 4 NDM, 6 GIM, 20 VIM, and 25 OXA-48-producing isolates). The sensitivity of the CRE agar for the detection of CPE was 94 % (89/95), but differed per carbapenemase gene (100 % for KPC, NDM, and GIM, 90 % for VIM, and 84 % for OXA-48-producing isolates). The specificity of the CRE agar was 71 %, due to the growth of AmpC- and/or ESBL-producing isolates. The CRE agar is a sensitive tool for the detection of KPC and metallo-carbapenemase-producing Enterobacteriaceae, although the detection of OXA-48 producers is less optimal. The relatively low specificity requires confirmation of carbapenemase production for isolates recovered from the CRE agar.

Detection, treatment, and prevention of carbapenemase-producing Enterobacteriaceae: Recommendations from an International Working Group

The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has increased during the past 10 years. Its detection is frequently difficult, because they do not always show a minimum inhibitory concentration (MIC) value for carbapenems in the resistance range. Both broth microdilution and agar dilution methods are more sensitive than disk diffusion method, Etest and automated systems. Studies on antimicrobial treatment are based on a limited number of patients; therefore, the optimal treatment is not well established. Combination therapy with two active drugs appears to be more effective than monotherapy. Combination of a carbapenem with another active agent — preferentially an aminoglycoside or colistin — could lower mortality provided that the MIC is ≤4 mg/l and probably ≤8 mg/l, and is administered in a higher-dose/prolonged-infusion regimen. An aggressive infection control and prevention strategy is recommended, including reinforcement of hand hygiene, using contact precautions and early detection of CPE through use of targeted surveillance.

Comparison of four laboratory methods in the detection of carbapenemase-producing Enterobacteriaceae

Comparison of four laboratory methods in the detection of carbapenemase-producing Enterobacteriaceae