Cloacae Isolates Research Articles

In vitro susceptibility to 19 agents other than β-lactams among third-generation cephalosporin-resistant Enterobacteriaceae recovered on hospital admission.

As part of the multicentre Antibiotic Therapy Optimisation Study, MIC values of 19 non-β-lactam agents were determined for third-generation cephalosporin-resistant Escherichia coli , Klebsiella species and Enterobacter species (3GCREB) isolates collected in German hospitals. A total of 328 E. coli , 35 Klebsiella spp. (1 Klebsiella oxytoca and 34 Klebsiella pneumoniae ) and 16 Enterobacter spp. (1 Enterobacter aerogenes and 15 Enterobacter cloacae ) isolates were submitted to broth microdilution antimicrobial susceptibility testing with the MICRONAUT system. MICs of fluoroquinolones (levofloxacin and moxifloxacin), aminoglycosides (gentamicin, tobramycin, amikacin, streptomycin, neomycin and paromomycin), tetracyclines (tetracycline, minocycline and tigecycline), macrolides (erythromycin, clarithromycin and azithromycin) and miscellaneous agents [trimethoprim/sulfamethoxazole, chloramphenicol, nitrofurantoin, colistin and fosfomycin intravenous (iv)] were determined and reviewed against 2016 EUCAST breakpoints. The MIC of levofloxacin was >2 mg/L for 128 of 328 E. coli and 8 of 35 Klebsiella spp., but only 1 of 16 Enterobacter spp. Rates of resistance to trimethoprim/sulfamethoxazole were high (>70%), except for Enterobacter spp. Rates of resistance to colistin and fosfomycin iv were still low. About 20% of the tested isolates were resistant to chloramphenicol. Only 1 (of 328) E. coli isolate had an MIC of amikacin >16 mg/L and only 33 of 328 E. coli and 1 of 35 Klebsiella spp. had an MIC of tobramycin >4 mg/L, whereas average gentamicin MICs were in general more elevated. A tigecycline MIC >2 mg/L was only found for 1 of 16 Enterobacter spp., but in none of the E. coli or Klebsiella spp. isolates. Our study gives insight into previously unreported non-β-lactam MIC distributions of 3GCREB isolates.

Isolation and Identification of Nonoral Pathogenic Bacteria in the Oral Cavity of Patients with Removable Dentures.

Aims and Objectives:Dentures in the oral cavity may act as a reservoir of microorganisms, which may be related to systemic infections. The aim of this study was to investigate the nonoral pathogenic bacteria in the oral cavity of patients with removable dentures in Shiraz, Southern Iran.Materials and Methods:The bacterial flora of saliva samples from 50 men and 50 women with removable dentures and 100 age- and sex-matched controls with normal dentate were compared using culture, Gram staining, and API20E Kit methods. All data were analyzed using SPSS software.Results:Except for Enterobacter cloacae isolate (P = 0.03), there was no significant difference between both groups for the presence of Escherichia coli, Klebsiella pneumoniae, nonfermenting Gram-negative bacilli, Raoultella ornithinolytica, Raoultella planticola, Kluyvera spp., and Enterobacter aerogenes. No significant correlation was noticed between age and presence of bacteria in the oral cavity. The Gram-negative rod bacteria were more in males, but the difference was not significant. When a total of Gram-negative rods were considered, there was a significant difference between case and control groups (P = 0.004).Conclusions:Based on our findings that nonoral pathogenic bacteria are detected from the saliva of the denture wearers, general and oral health measures in patients with removable dentures should be adopted to decrease the risk of cross infection.

Detection of Curlibiogenesis genes among Enterobacter cloacae isolates and their role in biofilm formation in Al-Hilla City, Iraq

In this study, (100) clinical samples were collected from patients with urinary tract infection (UTI). Samples were then subjected for culturing on selective media to isolate Enterobacter cloacae. All clinical samples were positive culture, only (62) samples showed positive cultures, as gram negative bacteria whereas (38) bacterial growth were detected as gram positive bacteria. Among (62)gram negative bacteria, only 12(19.4%) isolates belonged to Enterobacter cloacae, isolates were identified by API20E. Sequencing of hsp60 gene and alignment of (341) base pare confirmed the identity of 8(12.9%) isolates. All DNA samples extracted from bacterial isolates were conducted for polymerase chain reaction to investigate presence of curli genes among isolates. The result revealed that 8(100%) of isolates were positive to Curli-specific Genes D(CsgD)gene, The Curli-specific Genes D (csgD)genes showed a bands of expected size (355) base pare in (8) isolates E. cloacae under study. Six of eight Enterobacter cloacae isolates produced (245) base pare amplification bands of Curli-specific Genes A (csgA)gene (75%). The results display significant positive correlation between biofilm formation and curlifambriae adhesion. Our results conclude the importance of curli fimbriae adhesion in establishment of biofilm and magnitude of biofilm formation in urinary tract infection (UTI)via antibiotics resistance and ascending infections.

The occurrence of CTX-M-25-producing Enterobacteriaceae in day-old broiler chicks in Japan.

Day-old chicks from 3 hatcheries were placed on bedding paper and brought to a commercial broiler farm between January and July 2016. Sixty-six samples of the paper, which were stained with meconium droppings of the chicks, were collected and examined for isolation of cephalosporin-resistant Enterobacteriaceae. Cefotaxime (CTX)-resistant Klebsiella pneumoniae (1 isolate) and Enterobacter cloacae (4 isolates) were isolated from 5 (7.58%) of the 66 samples. Conjugation experiments revealed that the blaCTX-M-25 gene conferring CTX resistance was transferred from the K. pneumoniae isolate and 2 of the 4 E. cloacae isolates to Escherichia coli DH5α via IncA/C plasmids carrying the gene. Our results suggested that the blaCTX-M-25 gene originating from chicks may be spread among commercial broiler farms.

Molecular epidemiology of environmental and clinical carbapenemase-producing Gram-negative bacilli from hospitals in Guelma, Algeria: Multiple genetic lineages and first report of OXA-48 in Enterobacter cloacae.

This study was designed to investigate environmental colonisation in Algerian hospitals by carbapenem-resistant Gram-negative bacilli (GNB), including molecular characterisation of their resistance, and to perform a comparative molecular analysis between clinical and environmental strains. GNB isolated from hospitalised patients and the hospital environment were identified using microbiological methods and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed by disk diffusion and Etest methods. Carbapenemase- and extended-spectrum β-lactamase (ESBL)-encoding genes were searched for using PCR and sequencing. Clonality of the environmental and clinical strains was assessed by multilocus sequencing typing (MLST). A total of 32 carbapenem-resistant GNB were isolated, including 16 (29%) of 56 multidrug-resistant (MDR) GNB from clinical specimens and 16 (48%) of 33 MDR-GNB from inanimate surfaces. Of the 32 carbapenem-resistant isolates, 14 produced a carbapenemase. The blaOXA-48 gene was detected both in clinical and surface isolates of Klebsiella pneumoniae (n=3) and Enterobacter cloacae (n=2). Clinical and surface isolates of Acinetobacter baumannii were found to produce the carbapenemases NDM-1 (7 isolates) and OXA-23 (2 isolates). MLST revealed clonal diversity and a relationship between environmental and clinical strains with identical sequence types. Here we report the first description of an OXA-48-producing E. cloacae isolate in Algeria. We also highlight the important role of inanimate surfaces in the spread of carbapenem-resistant bacteria and the emergence of nosocomial infections.

High prevalence of non-clonal imipenem-nonsusceptible Enterobacter spp. isolates in Korea and their association with porin down-regulation

We investigated the prevalence and clonal distribution of imipenem-nonsusceptible Enterobacter clinical isolates from hospitals in Korea and the contributions of various mechanisms to imipenem nonsusceptibility. The in vitro antimicrobial susceptibility to imipenem of 357 non-duplicated Enterobacter isolates obtained from eight geographically distant tertiary care hospitals in Korea was evaluated. Imipenem-nonsusceptible Enterobacter isolates were genotyped. Additionally, β-lactamase genes were screened using PCR, and the expression of efflux pump and porin genes was investigated using quantitative RT-PCR. A total of 31 isolates (8.7%) were not susceptible to imipenem. Clonal diversity of 17 imipenem-nonsusceptible E. cloacae isolates was demonstrated by multilocus sequence typing. Fourteen imipenem-nonsusceptible E. aerogenes isolates were found to be distantly genetically related by an ERIC-PCR analysis. Expression levels of porin ompD and ompK35 genes were decreased in all imipenem-nonsusceptible E. cloacae and E. aerogenes isolates. However, only two isolates were found positive for blaIMP and blaVIM genes, and expression of the efflux pump gene, acrB, was not associated with reduced imipenem susceptibility. Imipenem resistance seems to have occurred independently in most of the imipenem-nonsusceptible isolates in this study, and decreased porin expression was found to be the main mechanism underlying this reduced susceptibility to imipenem.

National survey of colistin resistance among carbapenemase-producing Enterobacteriaceae and outbreak caused by colistin-resistant OXA-48-producing Klebsiella pneumoniae, France, 2014.

From January 2014 to December 2014, 972 consecutive non-replicate carbapenemase-producing Enterobacteriaceae isolates from colonised or infected patients were collected at the Associated French National Reference Centre as part of the French national survey on antimicrobial resistance. It included 577 Klebsiella spp. (59%), 236 Escherichia coli (24%), 108 Enterobacter spp. (11%), 50 Citrobacter spp. (5%), and a single Salmonella spp. isolate (0.1%). Of 561 K. pneumoniae isolates, 35 were found to be resistant to colistin (6.2%). PFGE analysis revealed a clonal outbreak involving 15 K. pneumoniae isolates belonging to sequence type ST11, recovered in a single hospital in the Picardie region in northern France. Those clonally related isolates showed variable levels of resistance to colistin, ranging from 4 to 64 mg/L. They harboured the blaOXA-48 carbapenemase gene and the blaCTX-M-15 extended-spectrum beta-lactamase gene. Among the 91 Enterobacter cloacae isolates, seven were resistant to colistin and produced different types of carbapenemases. Surprisingly, none of the E. coli and Citrobacter spp. isolates showed resistance to colistin. This national survey including carbapenemase-producing isolates recovered in 2014 reported a high rate of colistin resistance in K. pneumoniae and E. cloacae (6.2% and 7.7%, respectively) in France.

Characterization of extended-spectrum β-lactamase (ESBL)-producing Klebsiella, Enterobacter, and Citrobacter obtained in environmental samples of a Tunisian hospital

The assessment of the hospital environment as a reservoir of ESBL-producing Enterobacteriaceae in Tunisian hospitals is scarcely analyzed, except for Escherichia coli. The aim of this study was to evaluate the presence of ESBL-producing non-E. coli Enterobacteriaceae (ESBL-EbNoEc) in 300 samples of abiotic surfaces and the hands of patients and staff of a Tunisian Hospital, and to characterize the ESBL genes of the recovered isolates. ESBL-EbNoEc were recovered in 28 of 300 (9.3%) analyzed samples and were identified as Klebsiella pneumoniae (n= 11), Enterobacter cloacae (n=11), Citrobacter freundii (n=4) and Klebsiella oxytoca (n=2). The bla genes identified by PCR and sequencing among the strains were as follows: 11 K.pneumoniae strains [blaCTX-M-15+ blaTEM-1+ blaSHV-11 (n=6); blaCTX-M-15+ blaTEM-1+ blaSHV-28 (n=3); blaCTX-M-15+ blaTEM-1+ blaSHV-1 (n=2)], 11 E. cloacae strains [blaCTX-M-15 (n=6); blaCTX-M-15+ blaTEM-1b (n=2); blaCTX-M-15+ blaTEM-1b+ blaOXA-1 (n=1);blaCTX-M-15+ blaOXA-1 (n=1);blaSHV-12 (n=1)], 4 C. freundii strains [blaCTX-M-15] and 2 K. oxytoca strains [blaCTX-M-15 (n=1); blaSHV-12 (n=1)]. The ISEcp1 and orf477 sequences were identified upstream and downstream of the blaCTX-M-15 gene, respectively, in 3 K. pneumoniae and 3 E. cloacae isolates. The PFGE analysis demonstrated three unrelated pulsotypes in K. pneumoniae strains and five pulsotypes in E. cloacae. The uncontrolled dissemination of ESBL-producing bacteria, even in the hospital environment, has become a real problem and new strategies and hygienic rules are needed to stop this bacterial dissemination.

In Vitro Activity of Polymyxin B in Combination with Various Antibiotics against Extensively Drug-Resistant Enterobacter cloacae with Decreased Susceptibility to Polymyxin B.

Against extensively drug-resistant (XDR) Enterobacter cloacae, combination antibiotic therapy may be the only option. We investigated the activity of various antibiotics in combination with polymyxin B using time-kill studies (TKS). TKS were conducted with four nonclonal XDR E. cloacae isolates with 5 log10 CFU/ml bacteria against maximum, clinically achievable concentrations of polymyxin B alone and in two-drug combinations with 10 different antibiotics. A hollow-fiber infection model (HFIM) simulating clinically relevant polymyxin B and tigecycline dosing regimens was conducted for two isolates over 240 h. Emergence of resistance was quantified using antibiotic-containing (3× MIC) media. Biofitness and stability of resistant phenotypes were determined. All XDR E. cloacae isolates were resistant to all antibiotics except for polymyxin B (polymyxin B MIC, 1 to 4 mg/liter). All isolates harbored metallo-β-lactamases (two with NDM-1, two with IMP-1). In single TKS, all antibiotics alone demonstrated regrowth at 24 h, except amikacin against two strains and polymyxin B and meropenem against one strain each. In combination TKS, only polymyxin B plus tigecycline was bactericidal against all four XDR E. cloacae isolates at 24 h. In HFIM, tigecycline and polymyxin B alone did not exhibit any killing activity. Bactericidal kill was observed at 24 h for both isolates for polymyxin B plus tigecycline; killing was sustained for one isolate but regrowth was observed for the second. Phenotypically stable resistant mutants with reduced in vitro growth rates were observed. Polymyxin B plus tigecycline is a promising combination against XDR E. cloacae However, prolonged and indiscriminate use can result in resistance emergence.

PDGO100, a type 1 IncC plasmid from 1981 carrying ARI-A and a Tn1696-like transposon in a novel integrating element

Most A/C plasmids sequenced to date were recovered in the last two decades. To gain insight into the evolution of this group, the IncC plasmid pDGO100, found in a multiply antibiotic-resistant Escherichia coli strain isolated in 1981, was sequenced. pDGO100 belongs to the type 1 lineage and carries an ARI-A antibiotic resistance island but not an ARI-B island. The A/C2 backbone of pDGO100 has a deletion in the rhs1 gene previously found in pRMH760 and differs by only six single base pair substitutions from pRMH760, recovered at the same hospital 16years later. This confirms that the separation of type 1 and type 2 IncC plasmids is long standing. The ARI-A islands are also closely related, but pRMH760 contains Tn4352B in tniA of Tn402, while in pDGO100, Tn4352 has inserted into merA of pDUmer. pDGO100 also carries an additional 46kb insertion that includes a Tn1696-like transposon with the dfrB3 gene cassette. This insertion was identified as a novel integrating element, with an int gene at one end, and also includes the fec iron uptake operon that has been acquired from the E. coli chromosome. Related integrating elements carrying the same int gene were found in A/C2, IncHI1, and IncHI2 plasmids, and in the chromosomes of Enterobacter cloacae, Klebsiella oxytoca, and Cronobacter sakazakii isolates. In the Enterobacteriaceae chromosomes, these integrating elements appear to target a gene encoding a radical SAM superfamily protein. In the A/C2, IncHI1, and IncHI2 plasmids, genes encoding a phosphoadenosine phosphosulfate reductase were interrupted. The extremities of the integrating element are highly conserved, whilst the internal gene content varies. The detection of integrative elements in plasmids demonstrates an increased range of locations into which this type of mobile element can integrate and insertion in plasmids is likely to assist their spread.

Neonatal infections with multidrug-resistant ESBL-producing E. cloacae and K. pneumoniae in Neonatal Units of two different Hospitals in Antananarivo, Madagascar.

BackgroundWe investigated the molecular mechanism of ß-lactam resistance in extended-spectrum ß-lactamase (ESBL)-producing Enterobacterial strains isolated in neonatal units of different hospitals in Anatnanarivo, Madagascar.MethodsBacteria were identified by standard biochemical methods, disc diffusion antibiograms and Etest. Resistance genes were sought by PCR. Strains were characterized by Rep-PCR (Diversilab), plasmid analysis and rep-typing.ResultsFrom April 2012 to March 2013, 29 ESBL-producing E. cloacae and 15 K. pneumoniae were isolated from blood culture (n = 32) or gastric samples (n = 12) performed at day 0 or 2 from 39/303 newborns suspected of early neonatal infection. These infants were treated with expanded spectrum cephalosporins, due to lack of carbapenems, leading to a high mortality rate (45 %). Isolates recovered were all, but 4, multidrug resistant, particularly to fluoroquinolones (FQ) except for 21 E. cloacae isolates. Isolates produced TEM-1 and CTX-M-15 ß-lactamases and their genes were located on several self-transferable plasmids of variable sizes sizes that could not be linked to a major plasmid incompatibility group. E. cloacae isolates belonged to 6 Rep-types among which two counted for 11 isolates each. The FQ resistant E. cloacae isolates belonged to one clone, whereas the FQ susceptible E. cloacae isolates belonged to four clones. The K. pneumoniae isolates belonged to 9 Rep-types among which one included five isolates.ConclusionThis study is the first molecular characterization of ESBL-producing isolates from neonatology units in Madagascar, a country with limited epidemiological data. It revealed an important multi-clonal dissemination of CTX-M-15-producing isolates reflecting both the high community carriage and the very early nosocomial contamination of the neonates.

High prevalence of plasmid-mediated quinolone resistance determinants in Enterobacter cloacae isolated from hospitals of the Qazvin, Alborz, and Tehran provinces, Iran.

Plasmid-mediated quinolone resistance (PMQR) is a growing clinical concern worldwide. The main aims of this study were to detect qnr-encoding genes and to evaluate the clonal relatedness of qnr-positive Enterobacter cloacae isolates. A total of 116 E. cloacae isolates that were not susceptible to quinolone were obtained from seven hospitals in Tehran, five hospitals in Qazvin, and two hospitals in Karaj (Iran). Bacterial identification was performed using standard laboratory methods and API 20E strips. Quinolone resistance was determined using the Kirby-Bauer disk diffusion method according to the Clinical Laboratory Standards Institute (CLSI) guidelines. PCR and sequencing were employed to detect qnrA, qnrB, and qnrS genes, and clonal relatedness was assessed using the enterobacterial repetitive intergenic consensus (ERIC)-PCR method. In total, 45 (38.8%) and 71 (61.2%) of isolates showed high- and low-level quinolone resistance, respectively, and qnr-encoding genes were detected in 70 (60.3%) of them. qnrB1 [45 (38.8%) isolates] was the most commonly detected gene, followed by qnrS1 [28 (24.1%) isolates] and qnrB4 [18 (15.5%) isolates] either alone or in combination with other genes. The results of the ERIC-PCR revealed that 53 (75.7%) qnr-positive isolates were genetically unrelated. This study describes, for the first time, the high prevalence of the qnrB1, qnrS1, and qnrB4 genes among E. cloacae isolates in Iran. The detection of qnr genes emphasizes the need for establishing tactful policies associated with infection control measures in hospital settings in Iran.

Molecular characterization of class b carbapenemases in advanced stage of dissemination and emergence of class d carbapenemases in Enterobacteriaceae from Croatia

Carbapenemases involved in acquired carbapenem resistance in Enterobacteriaceae belong to Ambler class A serin β-lactamases, class B metallo-β-lactamases (MBL) or class D OXA-48-like β-lactamases. The aim of the present study was to analyse the molecular epidemiology and the mechanisms and routes of spread of class B and class D carbapenemases in Croatia.In total 68 isolates were analyzed. Antibiotic susceptibility was determined by broth microdilution method. PCR was used to detect antibiotic-resistance genes. Genotyping was performed by rep-PCR and MLST.Sixty-five isolates were found to harbour VIM-1 carbapenemase, seven of which were positive also for NDM-1, while two strains harboured only NDM-1. OXA-48 was detected in three isolates, two of which coproduced VIM-1. Thirty-six strains possessed additional CTX-M-15 β-lactamase whereas 64 were positive for TEM-1. CMY was found in 18 Citrobacter freundii isolates and DHA-1 in one Enterobacter cloacae isolate. Four different plasmid-incompatibility groups were found: A/C, L/M, N and FIIAs. Unlike C. freundii and E. cloacae, Klebsiella pneumoniae showed high diversity of rep-PCR patterns. E. cloacae and C. freundii predominantly belonged to one large clone which was allocated to ST105 and ST24, respectively.Three different types of carbapenemases were identified showing the complexity of CRE in Croatia.

Antibiotic failure mediated by a resistant subpopulation in Enterobacter cloacae.

Antibiotic resistance is a major public health threat, further complicated by unexplained treatment failures caused by bacteria that appear antibiotic susceptible. We describe an Enterobacter cloacae isolate harbouring a minor subpopulation that is highly resistant to the last-line antibiotic colistin. This subpopulation was distinct from persisters, became predominant in colistin, returned to baseline after colistin removal and was dependent on the histidine kinase PhoQ. During murine infection, but in the absence of colistin, innate immune defences led to an increased frequency of the resistant subpopulation, leading to inefficacy of subsequent colistin therapy. An isolate with a lower-frequency colistin-resistant subpopulation similarly caused treatment failure but was misclassified as susceptible by current diagnostics once cultured outside the host. These data demonstrate the ability of low-frequency bacterial subpopulations to contribute to clinically relevant antibiotic resistance, elucidating an enigmatic cause of antibiotic treatment failure and highlighting the critical need for more sensitive diagnostics.

Survey of Clinical Extended-Spectrum Beta-Lactamase-Producing Enterobacter cloacae Isolates in a Chinese Tertiary Hospital, 2012-2014.

A total of 72 consecutive and nonduplicate clinical extended-spectrum β-lactamase (ESBL)-producing Enterobacter cloacae isolates were collected from our hospital from 2012 to 2014 for analyzing the prevalence of plasmid-mediated quinolone resistance (PMQR) genes, 16S rRNA methyltransferase (16S-RMTase) encoding genes, and carbapenem-hydrolyzing β-lactamase (CHβL) genes, as well as integrons. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were carried out to characterize the genetic relatedness. The isolates mainly harbored blaCTX-M (n = 51, 70.8%) and blaSHV (n = 46, 63.9%) genes. High prevalence of PMQR genes qnrA1 (n = 24, 33.3%), qnrB (n = 4, 5.6%), qnrS1 (n = 2, 2.8%), and aac(6')-Ib-cr (n = 21, 29.2%) was observed. Furthermore, CHβLs IMP-4 (n = 6, 8.3%) and IMP-8 (n = 4, 5.6%), as well as class I integrons (n = 29, 40.3%), were found in the ESBL-producing E. cloacae isolates. PFGE revealed 69 pulsotypes. MLST distinguished 44 sequence types (STs) with ST124 (n = 7, 9.7%), ST50 (n = 3, 4.2%), ST45 (n = 3, 4.2%), and ST93 (n = 3, 4.2%) being the predominant STs. The results indicate a possible clonal transmission of ST124 isolates in the hospital that needs further surveillance. The genetic diversity of the other numerous distinctive STs indicates that most of the ESBL-producing E. cloacae in our hospital might arise through stepwise accumulations of multiple drug-resistance determinants in different clones.

Species Diversity of Environmental GIM-1-Producing Bacteria Collected during a Long-Term Outbreak.

Reports of outbreaks concerning carbapenemase-producing Gram-negative bacteria in which the main source of transmission is the hospital environment are increasing. This study describes the results of environmental sampling in a protracted polyspecies metallo-beta-lactamase GIM-1 outbreak driven by plasmids and bacterial clones of Enterobacter cloacae and Pseudomonas aeruginosa in a tertiary care center. Environmental sampling targeting wet locations (especially sinks) was carried out on a surgical intensive care unit and on a medical ward on several occasions in 2012 and 2013. We were able to demonstrate 43 blaGIM-1-carrying bacteria (mainly nonfermenters but also Enterobacteriaceae) that were either related or unrelated to clinical strains in 30 sinks and one hair washbasin. GIM-1 was found in 12 different species, some of which are described here as carriers of GIM-1. Forty out of 43 bacteria displayed resistance to carbapenems and, in addition, to various non-beta-lactam antibiotics. Colistin resistance was observed in two E. cloacae isolates with MICs above 256 mg/liter. The blaGIM-1 gene was harbored in 12 different class 1 integrons, some without the typical 3' end. The blaGIM-1 gene was localized on plasmids in five isolates. In vitro plasmid transfer by conjugation was successful in one isolate. The environment, with putatively multispecies biofilms, seems to be an important biological niche for multidrug-resistant bacteria and resistance genes. Biofilms may serve as a "melting pot" for horizontal gene transfer, for dissemination into new species, and as a reservoir to propagate future hospital outbreaks. In Gram-negative bacteria, resistance to the clinically relevant broad-spectrum carbapenem antibiotics is a major public health concern. Major reservoirs for these resistant organisms are not only the gastrointestinal tracts of animals and humans but also the (hospital) environment. Due to the difficulty in eradicating biofilm formation in the latter, a sustained dissemination of multidrug-resistant bacteria from the environment can occur. In addition, horizontal transfer of resistance genes on mobile genetic elements within biofilms adds to the total "resistance gene pool" in the environment. To gain insight into the transmission pathways of a rare and locally restricted carbapenemases resistance gene (blaGIM-1), we analyzed the genetic background of the blaGIM-1 gene in environmental bacteria during a long-term polyspecies outbreak in a German hospital.

What does the susceptible-dose dependent interpretive category for cefepime in ESBL-producing bacteria?

In this study, we investigated the frequency of isolates included in the susceptible-dose dependent (SDD) category, according to the Clinical and Laboratory Standards Institute guidelines, carrying blaTEM, blaSHV and blaCTX genes among 92 Klebsiella pneumoniae and 80 Enterobacter cloacae clinical isolates. The presence of one or more extended-spectrum β-lactamases (ESBLs) genes was observed in 64% K. pneumoniae and 69% E. cloacae isolates. Nineteen isolates were included in SDD interpretive category criteria, of which 15 carried ESBL genes (seven K. pneumoniae and eight E. cloacae). Considering the high proportion of ESBL gene-containing isolates included in the SDD category (79%), we recommend that physicians exercise caution in the use of cefepime for treatment of infections caused by these isolates, reducing possible therapeutic failure, particularly in cases of ESBL-producing bacterial strains.

Extended-spectrum ß-Lactamase-producing Enterobacteriaceae as a Common Cause of Urinary Tract Infections in Sri Lanka.

BackgroundExtended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) are increasingly reported as pathogens in urinary tract infections (UTIs). However, in Sri Lanka, the clinical and molecular epidemiology of ESBL-PE implicated in UTIs has not been well described.Materials and MethodsWe conducted prospective, laboratory-based surveillance from October to December 2013 at a tertiary care hospital in southern Sri Lanka and enrolled patients ≥1 year of age with clinically relevant UTIs due to ESBL-PE. Isolate identity, antimicrobial drug susceptibility, and ESBL production were determined. Presence of ß-lactamase genes, bla SHV, bla TEM, and bla CTX-M, was identified by polymerase chain reaction.ResultsDuring the study period, Enterobacteriaceae were detected in 184 urine samples, with 74 (40.2%) being ESBL producers. Among 47 patients with ESBL-PE who had medical records available, 38 (80.9%) had clinically significant UTIs. Most UTIs (63.2%) were community acquired and 34.2% were in patients with diabetes. Among 36 cultured ESBL-PE isolates, significant susceptibility (>80%) was only retained to amikacin and the carbapenems. The group 1 bla CTX-M gene was present in 90.0% of Escherichia coli isolates and all Klebsiella pneumoniae and Enterobacter cloacae isolates. The bla SHV and bla TEM genes were more common in K. pneumoniae (75% and 50%) and E. cloacae (50% and 50%) isolates than in E. coli (10% and 20%) isolates, respectively.ConclusionThe majority of UTIs caused by ESBL-PE were acquired in the community and due to organisms carrying the group 1 CTX-M ß-lactamase. Further epidemiologic studies of infections due to ESBL-PE are urgently needed to better prevent and treat these infections in South Asia.

Epidemiologic and Genotypic Review of Carbapenemase-Producing Organisms in British Columbia, Canada, between 2008 and 2014.

Carbapenemase-producing organisms (CPOs) are a serious emerging problem for health care facilities worldwide. Owing to their resistance to most antimicrobial therapies, CPOs are difficult to treat and pose a challenge for infection prevention and control. Since 2010, lab-based surveillance for CPOs and PCR-based testing were implemented in British Columbia (BC), Canada. A review of CPOs in BC from 2008 to March 2014 was done to characterize the resistance mechanisms and possible clonal strain transmission and to compare pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and plasmid restriction fragment length polymorphism (RFLP) as molecular typing tools. During this study period, a total of 177 CPO cases were identified. Patient demographics and travel history were reviewed, and a descriptive analysis was carried out. PFGE profiles, MLST, and plasmid RFLP analysis for a subset of Escherichia coli, Klebsiella pneumoniae, and Enterobacter species isolates were obtained and analyzed. Our findings demonstrate that CPOs have been increasing in number in BC over time, from 1 isolate/year retrospectively identified in 2008 and 2009 to 82 isolates in 2013 and 30 isolates in the first quarter of 2014. Overall, K. pneumoniae isolates lack clonality, although some seemingly related clusters have been found. Plasmid analysis showed evidence of the spread of plasmids carrying carbapenemase-encoding genes between the examined isolates. Analysis of Enterobacter cloacae isolates revealed a more clonal nature of these CPOs in BC. The presence of related clusters provides evidence of interpatient organism transmission both within and between institutions. Although in our study, NDM-harboring E. cloacae isolates appeared to spread clonally, the spread of carbapenem resistance in K. pneumoniae seems to be plasmid mediated.

The spread of bla OXA-48 and bla OXA-244 carbapenemase genes among Klebsiella pneumoniae, Proteus mirabilis and Enterobacter spp. isolated in Moscow, Russia

BackgroundThe spread of carbapenemase-producing Enterobacteriaceae (CPE) is a great problem of healthcare worldwide. Study of the spread for blaOXA-48-like genes coding epidemically significant carbapenemases among hospital pathogens is important for the regional and global epidemiology of antimicrobial resistance.MethodsAntibacterial resistant isolates of Klebsiella pneumoniae (n = 95) from 54 patients, P.mirabilis (n = 32) from 20 patients, Enterobacter aerogenes (n = 6) from four patients, and Enterobacter cloacae (n = 4) from four patients were collected from January, 2013 to October, 2014 in neurosurgical intensive care unit (ICU) of the Burdenko Neurosurgery Institute, Moscow. Characteristics of the isolates were done using susceptibility tests, PCR detection of the resistance genes, genotyping, conjugation, DNA sequencing, and bioinformatic analysis.ResultsMajor strains under study were multi drug resistant (MDR), resistant to three or more functional classes of drugs simultaneously—98.9 % K. pneumoniae, 100 % P.mirabilis, one E.aerogenes isolate, and one E.cloacae isolate. Molecular-genetic mechanism of MDR in K.pneumoniae and P.mirabilis isolates were based on carrying of epidemic extended-spectrum beta-lactamase blaCTX-M-15 gene (87.2 and 90.6 % accordingly), carbapenemase blaOXA-48-like gene (55.3 and 23.3 % accordingly), and class 1 (54.8 and 31.3 % accordingly) and class 2 (90.6 % P. mirabilis) integrons. The blaOXA-48-like-positive K. pneumoniae were collected during whole two-year surveillance period, while P. mirabilis and Enterobacter spp. carrying blaOXA-48-like genes were detected only after four and 18 months after the research start, respectively. The blaOXA-48-like gene acquisition was shown for P. mirabilis isolates collected from five patients and for E. cloacae isolate collected from one patient during their stay in the ICU, presumably from blaOXA-48-like-positive K. pneumoniae. The source of the blaOXA-244 gene acquired by E. aerogenes isolates and the time of this event were not recognized.ConclusionsThe expanding of CPE in the surveyed ICU was associated with the spread of blaOXA-48 and blaOXA-244 carbapenemase genes documented not only among K.pneumoniae, well-known bacterial host for such genes, but among P.mirabilis, E.aerogenes, and E. cloacae.