Project description:Fecal carriage of carbapenemase-producing Enterobacteriaceae (CPE) has not been extensively investigated, except in the cases of selected patients at risk, mostly during outbreaks. A total of 1,100 fecal samples randomly collected in our institution in two different periods in 2006 (n = 600) and 2009-2010 (n = 500) from hospitalized (26.8%) and nonhospitalized (73.2%) patients were screened for CPE. The first period coincided with an outbreak of VIM-1-producing Enterobacteriaceae, and the second one coincided with the emergence of KPC enzymes in our hospital. Diluted samples in saline were cultured in Luria-Bertani broth with 1 ?g/ml imipenem and subcultured in MacConkey agar plates with 4 ?g/ml ceftazidime. Growing colonies were screened for CPE (modified Hodge test and EDTA and boronic acid synergy tests). Carbapenemase genes, plasmids in which they are located, and clonal relatedness were determined. Individuals who exhibited fecal carriage of CPE (11/1,043, 1.1%; 95% confidence interval [CI], 0.53 to 1.88) included 8 hospitalized (carriage rate, 2.9%; 95% CI, 1.24 to 5.55) and 3 nonhospitalized patients (carriage rate, 0.4%; 95% CI, 0.08 to 1.14), the latter being identified in 2009. Eighty-two percent of colonized patients were not infected with CPE. Isolates harboring bla(VIM-1) with or without bla(SHV-12) were identified as Klebsiella pneumoniae (n = 8; ST39, ST688, ST253, and ST163), Enterobacter cloacae (n = 3; two pulsed-field gel electrophoresis [PFGE] types), Escherichia coli (n = 2; ST155 and ST2441), and Citrobacter freundii (n = 1). Some of these lineages had previously been detected in our institution. The bla(VIM-1) gene was a member of the class 1 integrons In110 (bla(VIM-1)-aacA4-aadA1) and In113 (bla(VIM-1)-aacA4-dhfrII) located on plasmids IncN (n = 11; 30 to 50 kb) and IncHI2 (n = 3; 300 kb), respectively. Dissemination of bla(VIM-1) class-1 integrons within highly transferable plasmids in a polyclonal population has potentially contributed to the maintenance and spread of CPE.
Project description:Carbapenem antimicrobials are critically important to human health and they are often the only remaining effective antibiotics for treating serious infections. Resistance to these drugs mediated by acquired carbapenemase enzymes is increasingly encountered in gram-negative bacteria and is considered a public health emergency. Animal origin food products are recognized as a potential source of resistant organisms, although carbapenem resistance has only recently been reported. In western countries there are active resistance surveillance programs targeting food animals and retail meat products. These programs primarily target beef, pork and poultry and focus exclusively on E. coli, Salmonella, Campylobacter spp. and Enterococcus spp. This global surveillance strategy does not capture the diversity of foods available nor does it address the presence of resistance gene-bearing mobile genetic elements in non-pathogenic bacterial taxa. To address this gap, a total of 121 seafood products originating in Asia purchased from retail groceries in Canada were tested. Samples were processed using a taxa-independent method for the selective isolation of carbapenem resistant organisms. Isolates were characterized by phenotypic antimicrobial susceptibility testing, PCR and DNA sequencing. Carbapenemase producing bacteria, all blaOXA-48, were isolated from 4 (3.3%) of the samples tested. Positive samples originated from China (n=2) and Korea (n=2) and included squid, sea squirt, clams and seafood medley. Carbapenemase producing organisms found include Pseudomonas, Stenotrophomonas and Myroides species. These findings suggest that non-pathogenic bacteria, excluded from resistance surveillance programs, in niche market meats may serve as a reservoir of carbapenemase genes in the food supply.
Project description:Acquired carbapenemases currently pose one of the most worrying public health threats related to antimicrobial resistance. A NDM-1-producing Salmonella Corvallis was reported in 2013 in a wild raptor. Further research was needed to understand the role of wild birds in the transmission of bacteria resistant to carbapenems. Our aim was to investigate the presence of carbapenem-resistant Escherichia coli in gulls from southern France. In 2012, we collected 158 cloacal swabs samples from two gull species: yellow-legged gulls (Larus michahellis) that live in close contact with humans and slender-billed gulls (Chroicocephalus genei) that feed at sea. We molecularly compared the carbapenem-resistant bacteria we isolated through culture on selective media with the carbapenem-susceptible strains sampled from both gull species and from stool samples of humans hospitalized in the study area. The genes coding for carbapenemases were tested by multiplex PCR. We isolated 22 carbapenem-resistant E. coli strains from yellow-legged gulls while none were isolated from slender-billed gulls. All carbapenem-resistant isolates were positive for blaVIM-1 gene. VIM-1-producing E. coli were closely related to carbapenem-susceptible strains isolated from the two gull species but also to human strains. Our results are alarming enough to make it urgently necessary to determine the contamination source of the bacteria we identified. More generally, our work highlights the need to develop more bridges between studies focusing on wildlife and humans in order to improve our knowledge of resistant bacteria transmission routes.
Project description:The emergence and spread of carbapenemase-producing gram-negative bacteria is a major public health concern. We used data collected from microbiology laboratories as part of the PIRASOA program during 2014-2018 to study the epidemiology of carbapenemase-producing bacteria in Andalusia, Spain. Our findings highlight the importance of ongoing surveillance and epidemiologic studies for these bacteria.
Project description:During 2013-2016, we isolated blaNDM- and blaVIM-harboring Enterobacteriaceae and nonfermentative bacteria from patients in the Philippines. Of 130 carbapenem-resistant isolates tested, 45 were Carba NP-positive; 43 harbored blaNDM, and 2 harbored blaVIM. Multidrug-resistant microbial pathogen surveillance and antimicrobial drug stewardship are needed to prevent further spread of New Delhi metallo-β-lactamase variants.
Project description:BackgroundCarbapenems are the last line of defence against ever more prevalent MDR Gram-negative bacteria, but their efficacy is threatened worldwide by bacteria that produce carbapenemase enzymes. The epidemiology of bacteria producing carbapenemases has been described in considerable detail in Europe, North America and Asia; however, little is known about their spread and clinical relevance in Africa.MethodsWe systematically searched in PubMed, EBSCOhost, Web of Science, Scopus, Elsevier Masson Consulte and African Journals Online, international conference proceedings, published theses and dissertations for studies reporting on carbapenemase-producing bacteria in Africa. We included articles published in English or French up to 28 February 2014. We calculated the prevalence of carbapenemase producers only including studies where the total number of isolates tested was at least 30.ResultsEighty-three studies were included and analysed. Most studies were conducted in North Africa (74%, 61/83), followed by Southern Africa (12%, 10/83), especially South Africa (90%, 9/10), West Africa (8%, 7/83) and East Africa (6%, 6/83). Carbapenemase-producing bacteria were isolated from humans, the hospital environment and community environmental water samples, but not from animals. The prevalence of carbapenemase-producing isolates in hospital settings ranged from 2.3% to 67.7% in North Africa and from 9% to 60% in sub-Saharan Africa.ConclusionsCarbapenemase-producing bacteria have been described in many African countries; however, their prevalence is poorly defined and has not been systematically studied. Antibiotic stewardship and surveillance systems, including molecular detection and genotyping of resistant isolates, should be implemented to monitor and reduce the spread of carbapenemase-producing bacteria.
Project description:BACKGROUND:Carbapenem-resistant Enterobacteriaceae (CRE) are associated with considerable mortality. As mechanisms of carbapenem resistance are heterogeneous, it is unclear if mortality differs based on resistance mechanisms. We sought to determine whether CRE resistance mechanism determination is prognostically informative. METHODS:We conducted an observational study comparing 14-day mortality between patients with carbapenemase-producing (CP)-CRE compared with non-CP-CRE bacteremia. Clinical data were collected on all patients. A comprehensive DNA microarray-based assay was performed on all isolates to identify ?-lactamase-encoding genes. RESULTS:There were 83 unique episodes of monomicrobial CRE bacteremia during the study period: 37 (45%) CP-CRE and 46 (55%) non-CP-CRE. The majority of CP-CRE isolates were bla KPC (92%), followed by bla NDM (5%) and bla OXA-48-type (3%). CP-CRE isolates were more likely to have meropenem minimum inhibitory concentrations (MICs) ?16 µg/mL, while non-CP-CRE isolates were more likely to have meropenem MICs ?1 µg/mL (P value < .001). A total of 18 (22%) patients died within 14 days, including 12 (32%) in the CP-CRE group and 6 (13%) in the non-CP-CRE group. Adjusting for severity of illness on day 1 of bacteremia, underlying medical conditions, and differences in antibiotic treatment administered, the odds of dying within 14 days were more than 4 times greater for CP-CRE compared with non-CP-CRE bacteremic patients (adjusted odds ratio, 4.92; 95% confidence interval, 1.01-24.81). CONCLUSION:Our findings suggest that CP-CRE may be more virulent than non-CP-CRE and are associated with poorer outcomes. This underscores the added importance of delineating underlying resistance mechanisms of CRE to direct antibiotic treatment decisions.
Project description:Non-carbapenemase-producing Gram negative bacteria, including ESBLs, AmpCs and non-beta-lactamase beta-lactams resistance mechanisms in clinical isolates from MDU Public Health Lab, Victoria, Australia Genome sequencing and assembly
Project description:Carbapenemase-producing Escherichia coli (CP-Ec) represents a major public health threat with a risk of dissemination in the community as has occurred for lineages producing extended-spectrum β-lactamases. To characterize the extent of CP-Ec spread in France, isolates from screening and infection samples received at the French National Reference Center (F-NRC) laboratory for carbapenemase-producing Enterobacterales were investigated. A total of 691 CP-Ec isolates collected between 2012 and 2015 and 22 isolates collected before 2012 were fully sequenced. Analysis of their genome sequences revealed some disseminating multidrug-resistant (MDR) lineages frequently acquiring diverse carbapenemase genes mainly belonging to clonal complex 23 (CC23) (sequence type 410 [ST410]) and CC10 (ST10 and ST167) and sporadic isolates, including rare ST131 isolates (n = 17). However, the most represented sequence type (ST) was ST38 (n = 92) with four disseminated lineages carrying blaOXA-48-like genes inserted in the chromosome. Globally, the most frequent carbapenemase gene (n = 457) was blaOXA-48. It was also less frequently associated with MDR isolates being the only resistance gene in 119 isolates. Thus, outside the ST38 clades, its acquisition was frequently sporadic with no sign of dissemination, reflecting the circulation of the IncL plasmid pOXA-48 in France and its high frequency of conjugation. In contrast, blaOXA-181 and blaNDM genes were often associated with the evolution of MDR E. coli lineages characterized by mutations in ftsI and ompC. IMPORTANCE Carbapenemase-producing Escherichia coli (CP-Ec) might be difficult to detect, as MICs can be very low. However, their absolute number and their proportion among carbapenem-resistant Enterobacterales have been increasing, as reported by WHO and national surveillance programs. This suggests a still largely uncharacterized community spread of these isolates. Here, we have characterized the diversity and evolution of CP-Ec isolated in France before 2016. We show that carbapenemase genes are associated with a wide variety of E. coli genomic backgrounds and a small number of dominant phylogenetic lineages. In a significant proportion of CP-Ec, the most frequent carbapenemase gene blaOXA-48, was detected in isolates lacking any other resistance gene, reflecting the dissemination of pOXA-48 plasmids, likely in the absence of any antibiotic pressure. In contrast, carbapenemase gene transfer may also occur in multidrug-resistant E. coli, ultimately giving rise to at-risk lineages encoding carbapenemases with a high potential of dissemination.
Project description:The aim of this work was to test a surveillance protocol able to detect extended-spectrum β-lactamase (ESBL)-, cephalosporinase (AmpC)- and carbapenemase (CP)-producing gram-negative bacteria in three conveniently chosen dairy farms with known prior occurrences of ESBL- and CP-producing strains. The protocol was applied monthly for a year. At each visit, 10 healthy lactating dairy cows were rectally swabbed, and raw milk filters (RMFs) were sampled in two of the three farms. Bacterial isolation was based on a first screening step with MacConkey agar supplemented with 1 mg/L cefotaxime and commercial carbapenem-supplemented media. We failed to detect CP-producing strains but showed that ESBL-Escherichia strains, found in one farm only (13 strains), were closely associated with multi-drug resistance (12 out of 13). The limited number of conveniently selected farms and the fact that RMFs could not be retrieved from one of them limit the validity of our findings. Still, our results illustrate that ESBL-status changes monthly based on fecal swabs and negative herds should be qualified as "unsuspected" as proposed by previous authors. Although surveillance of farm statuses based on RMF analysis could theoretically allow for a better sensitivity than individual swabs, we failed to illustrate it as both farms where RMFs could be retrieved were constantly negative. Determination of CP herd-level status based on RMFs and our surveillance protocol was hindered by the presence of intrinsically resistant bacteria or strains cumulating multiple non-CP resistance mechanisms which means our protocol is not specific enough for routine monitoring of CP in dairy farms.