Extended-spectrum beta-lactamase-producing bacteria are not detected in supragingival plaque samples from human fecal carriers of ESBL-producing Enterobacteriaceae

Background: The prevalence of infections caused by Cefotaximase-Munich (CTX-M)-type extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) has rapidly increased during the past 15 years. Enterobacteriaceae are commonly found in the gastrointestinal tract and long-term intestinal carriage is considered important for the spread of ESBL and as a source of clinical infections. Oral biofilm such as supragingival plaque is known to contain numerous antibiotic resistance determinants and may also represent a poorly investigated site for ESBL carriage and further spread. Objective: To investigate possible carriage of ESBL-producing bacteria in supragingival plaque of known fecal carriers of these bacteria. Design: We screened for the presence of aerobic and anaerobic ESBL-producing bacteria and blaCTX-M in supragingival plaque samples from healthy human adults with culture-verified fecal carriage of CTX-M-producing Escherichia coli. The presence or absence of Enterobacteriaceae and ESBL-producing bacteria in plaque samples was evaluated using culture-based methods and consensus CTX-M PCR. Results: Oral samples were obtained from 17 participants with known previous carriage of ESBL-producing E. coli. No ESBL-producing bacteria or ESBL genes were detected using culture-based and molecular methods. One colony of Rahnella aquatilis harboring the class A ESBL gene bla RAHN-1/2 was identified in an oral sample from one of the participants. Conclusion: This pilot study supports the notion that the presence of CTX-M-producing bacteria is uncommon in oral plaque of healthy human adult fecal carriers. Due to the limited number of persons tested, a low prevalence of oral ESBL-carriage in healthy adults or carriage in selected groups of patients cannot be excluded. To our knowledge, this is the first description of an R. aquatilis with the RAHN-1/2 gene in the oral cavity

Использование нетрадиционных методов лечения в дерматовенерологии

ВЕНЕРОЛОГИЯДЕРМАТОЛОГИЯМЕДИЦИНА ТРАДИЦИОННА

Antibiotic sensitivity screening of Klebsiella spp. and Raoultella spp. isolated from marine bivalve molluscs reveal presence of CTX-M-producing K. pneumoniae

Klebsiella spp. are a major cause of both nosocomial and community acquired infections, with K. pneumoniae being responsible for most human infections. Although Klebsiella spp. are present in a variety of environments, their distribution in the sea and the associated antibiotic resistance is largely unknown. In order to examine prevalence of K. pneumoniae and related species in the marine environment, we sampled 476 batches of marine bivalve molluscs collected along the Norwegian coast. From these samples, K. pneumoniae (n = 78), K. oxytoca (n = 41), K. variicola (n = 33), K. aerogenes (n = 1), Raoultella ornithinolytica (n = 38) and R. planticola (n = 13) were isolated. The number of positive samples increased with higher levels of faecal contamination. We found low prevalence of acquired resistance in all isolates, with seven K. pneumoniae isolates showing resistance to more than one antibiotic class. The complete genome sequence of cefotaxime-resistant K. pneumoniae sensu stricto isolate 2016-1400 was obtained using Oxford Nanopore and Illumina MiSeq based sequencing. The 2016-1400 genome had two contigs, one chromosome of 5,088,943 bp and one plasmid of 191,744 bp and belonged to ST1035. The β-lactamase genes blaCTX-M-3 and blaTEM-1, as well as the heavy metal resistance genes pco, ars and sil were carried on a plasmid highly similar to one found in K. pneumoniae strain C17KP0055 from South-Korea recovered from a blood stream infection. The present study demonstrates that K. pneumoniae are prevalent in the coastal marine environment and that bivalve molluscs may act as a potential reservoir of extended spectrum β-lactamase (ESBL)-producing K. pneumoniae that may be transmitted through the food chain.publishedVersio

An assessment on potential long-term health effects caused by antibiotic resistance marker genes in genetically modified organisms based on antibiotic usage and resistance patterns in Norway.

Source at https://vkm.no/Usage of antibiotics selects for resistant bacteria, resulting in reduced treatment options, and increased morbidity and mortality from microbial infections. Development of resistance in susceptible bacteria can occur through spontaneous mutation or horizontal gene transfer (HGT). Our current understanding of resistance development in bacterial pathogens is more descriptive than predictive in nature. That is, whereas the acquisition or development of new resistance determinants in bacteria can be retrospectively described relatively easily at the molecular, species and geographical distribution levels, the initial horizontal transfer events, the resistance gene donor, and the environmental location and conditions that produced the first generation of the resistant bacteria remain largely unknown. Without this latter knowledge and without a clear understanding of directional selection and genetic drift in natural bacterial populations, it is impossible to predict accurately further resistance development occurring through HGT. Some of the antibiotic resistance marker (ARM) genes used in the production of genetically modified organisms (GMO) encode resistance to antibiotics in clinical and veterinary use. Thus, concerns have been raised that the large-scale release of such genes in commercialized GMOs may increase the rate of, and broaden the locations where, bacteria horizontally acquire resistance genes

Antimicrobial susceptibility testing of Bacteroides species by disk diffusion: The NordicAST Bacteroides study

Objectives - Antimicrobial susceptibility testing (AST) of anaerobic bacteria has until recently been done by MIC methods. We have carried out a multi-centre evaluation of the newly validated EUCAST disk diffusion method for AST of Bacteroides spp. Methods - A panel of 30 Bacteroides strains was assembled based on reference agar dilution MICs, resistance gene detection and quantification of cfiA carbapenemase gene expression. Nordic clinical microbiology laboratories (n = 45) performed disk diffusion on Fastidious Anaerobe Agar with 5% mechanically defibrinated horse blood (FAA-HB) for piperacillin-tazobactam, meropenem and metronidazole. Results - A total of 43/45 (95.6%) laboratories carried out disk diffusion per protocol. Intraclass correlation coefficients were 0.87 (0.80–0.93) for piperacillin-tazobactam, 0.95 (0.91–0.97) for meropenem and 0.89 (0.83–0.94) for metronidazole. For metronidazole, one media lot yielded smaller zones and higher variability than another. Piperacillin-tazobactam and meropenem zone diameters correlated negatively with cfiA expression. A meropenem zone diameter of Conclusions - Inter-laboratory agreement by disk diffusion was good or very good. The main challenges were media-related variability for metronidazole and categorical disagreement with the reference method for piperacillin-tazobactam in some cfiA-positive strains. An area of technical uncertainty specific for such strains may be warranted

Carbapenem resistance determinants acquired through novel chromosomal integrations in extensively drug-resistant pseudomonas aeruginosa

Two novel blaDIM-1- or blaIMP-1-containing genomic islands (GIs) were discovered by whole-genome sequence analyses in four extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates from inpatients at a tertiary hospital in Ghana. The strains were of sequence type 234 (ST234) and formed a phylogenetic clade together with ST111, which is recognized as a global high-risk clone. Their carbapenem resistance was encoded by two Tn402-type integrons, In1592 (blaDIM-1) and In1595 (blaIMP-1), both carrying complete tni mobilization modules. In1595 was bound by conserved 25-bp inverted repeats (IRs) flanked by 5-bp direct repeats (DRs) associated with target site duplication. The integrons were embedded in two GIs that contained cognate integrases and were distinguished by a lower GC content than the chromosomal average. PAGI-97A (52.659 bp; In1592), which encoded a P4-type site-specific integrase of the tyrosine recombinase family in its 3′ border, was integrated into tRNA-Pro(ggg) and bracketed by a 49-bp perfect DR created by 3′-end target duplication. GIs with the same structural features, but diverse genetic content, were identified in 41/226 completed P. aeruginosa genomes. PAGI-97B (22,636 bp; In1595), which encoded an XerC/D superfamily integrase in its 5′ border, was inserted into the small RNA (sRNA) PrrF1/PrrF2 locus. Specific insertions into this highly conserved locus involved in iron-dependent regulation, all leaving PrrF1 intact, were identified in an additional six phylogenetically unrelated P. aeruginosa genomes. Our molecular analyses unveiled a hospital-associated clonal dissemination of carbapenem-resistant ST234 P. aeruginosa in which the XDR phenotype resulted from novel insertions of two GIs into specific chromosomal sites

Molecular Epidemiological Characterisation of ESBL- and Plasmid-Mediated AmpC-Producing Escherichia coli and Klebsiella pneumoniae at Kamuzu Central Hospital, Lilongwe, Malawi

The global rise in infections caused by multidrug resistant (MDR) Enterobacterales poses a public health problem. We have performed a molecular epidemiological characterisation of representative plasmid-mediated AmpC (pAmpC) and ESBL-positive clinical isolates of Escherichia coli (n = 38) and Klebsiella pneumoniae (n = 17) from a tertiary hospital in Malawi collected in 2017. BlaCTX-M-15 was the most prevalent ESBL-determinant in E. coli (n = 30/38) and K. pneumoniae (n = 17/17), whereas blaCMY-2 was detected in nearly all AmpC-phenotype E. coli (n = 15/17). Whole genome sequencing revealed dominant globally disseminated E. coli sequence types (STs); ST410 (n = 16), ST131 (n = 7), and ST617 (n = 6). The ST distribution in K. pneumoniae was more diverse but included ST101 (n = 2), ST14 (n = 2), and ST340 (n = 2), all considered high-risk MDR clones. The isolates expressed an MDR profile, including resistance against commonly used antibiotics, such as fluoroquinolones, aminoglycosides, and/or trimethoprim-sulfamethoxazole, and harboured corresponding resistance determinants. Clonal analyses of the major STs of E. coli revealed closely related genetic clusters within ST410, ST131, and ST617 supporting within-hospital transmission between patients and/or via a common reservoir. The overall findings add to the limited knowledge on the molecular epidemiology of MDR E. coli and K. pneumoniae in Malawi and may help health policy makers to identify areas to target when addressing this major threat of antibiotic resistance

High prevalence of multidrug resistant ESBL- and plasmid mediated AmpC-producing clinical isolates of Escherichia coli at Maputo Central Hospital, Mozambique

Background: Epidemiological data of cephalosporin-resistant Enterobacterales in Sub-Saharan Africa is still restricted,and in particular in Mozambique. The aim of this study was to detect and characterize extended-spectrum β-lactamase (ESBL) - and plasmid-mediated AmpC (pAmpC)-producing clinical strains of Escherichia coli at Maputo Central Hospital (MCH), a 1000-bed reference hospital in Maputo, Mozambique. Methods: A total of 230 clinical isolates of E. coli from urine (n = 199) and blood cultures (n = 31) were collected at MCH during August–November 2015. Antimicrobial susceptibility testing was performed by the disc diffusion method and interpreted according to EUCAST guidelines. Isolates with reduced susceptibility to 3rd generation cephalosporins were examined further; phenotypically for an ESBL−/AmpC-phenotype by combined disc methods and genetically for ESBL- and pAmpC-encoding genes by PCR and partial amplicon sequencing as well as genetic relatedness by ERIC-PCR. Results: A total of 75 isolates with reduced susceptibility to cefotaxime and/or ceftazidime (n = 75) from urine (n = 58/199; 29%) and blood (n = 17/31; 55%) were detected. All 75 isolates were phenotypically ESBL-positive and 25/75 (33%) of those also expressed an AmpC-phenotype. ESBL-PCR and amplicon sequencing revealed a majority of blaCTX-M (n = 58/75; 77%) dominated by blaCTX-M-15. All AmpC-phenotype positive isolates (n = 25/75; 33%) scored positive for one or more pAmpC-genes dominated by blaMOX/FOX. Multidrug resistance (resistance ≥ three antibiotic classes) was observed in all the 75 ESBL-positive isolates dominated by resistance to trimethoprimsulfamethoxazole, ciprofloxacin and gentamicin. ERIC-PCR revealed genetic diversity among strains with minor clusters indicating intra-hospital spread. Conclusion: We have observed a high prevalence of MDR pAmpC- and/or ESBL-producing clinical E. coli isolates with FOX/MOX and CTX-Ms as the major β-lactamase types, respectively. ERIC-PCR analyses revealed genetic diversity and some clusters indicating within-hospital spread. The overall findings strongly support the urgent need for accurate and rapid diagnostic services to guide antibiotic treatment and improved infection control measures

Investigating the mobilome in clinically important lineages of Enterococcus faecium and Enterococcus faecalis

Background: The success of Enterococcus faecium and E. faecalis evolving as multi-resistant nosocomial pathogens is associated with their ability to acquire and share adaptive traits, including antimicrobial resistance genes encoded by mobile genetic elements (MGEs). Here, we investigate this mobilome in successful hospital associated genetic lineages, E. faecium sequence type (ST)17 (n=10) and ST78 (n=10), E. faecalis ST6 (n=10) and ST40 (n=10) by DNA microarray analyses. Results: The hybridization patterns of 272 representative targets including plasmid backbones (n=85), transposable elements (n=85), resistance determinants (n=67), prophages (n=29) and clustered regularly interspaced short palindromic repeats (CRISPR)-cas sequences (n=6) separated the strains according to species, and for E. faecalis also according to STs. RCR-, Rep_3-, RepA_N- and Inc18-family plasmids were highly prevalent and with the exception of Rep_3, evenly distributed between the species. There was a considerable difference in the replicon profile, with rep17/pRUM, rep2/pRE25, rep14/EFNP1 and rep20/pLG1 dominating in E. faecium and rep9/pCF10, rep2/pRE25 and rep7 in E. faecalis strains. We observed an overall high correlation between the presence and absence of genes coding for resistance towards antibiotics, metals, biocides and their corresponding MGEs as well as their phenotypic antimicrobial susceptibility pattern. Although most IS families were represented in both E. faecalis and E. faecium, specific IS elements within these families were distributed in only one species. The prevalence of IS256-, IS3-, ISL3-, IS200/IS605-, IS110-, IS982- and IS4-transposases was significantly higher in E. faecium than E. faecalis, and that of IS110-, IS982- and IS1182-transposases in E. faecalis ST6 compared to ST40. Notably, the transposases of IS981, ISEfm1 and IS1678 that have only been reported in few enterococcal isolates were well represented in the E. faecium strains. E. faecalis ST40 strains harboured possible functional CRISPR-Cas systems, and still resistance and prophage sequences were generally well represented. Conclusions: The targeted MGEs were highly prevalent among the selected STs, underlining their potential importance in the evolution of hospital-adapted lineages of enterococci. Although the propensity of inter-species horizontal gene transfer (HGT) must be emphasized, the considerable species-specificity of these MGEs indicates a separate vertical evolution of MGEs within each species, and for E. faecalis within each ST

Molecular and epidemiological characterization of carbapenemase-producing Enterobacteriaceae in Norway, 2007 to 2014

Source at https://doi.org/10.1371/journal.pone.0187832 The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) is increasing worldwide. Here we present associated patient data and molecular, epidemiological and phenotypic characteristics of all CPE isolates in Norway from 2007 to 2014 confirmed at the Norwegian National Advisory Unit on Detection of Antimicrobial Resistance. All confirmed CPE isolates were characterized pheno- and genotypically, including by whole genome sequencing (WGS). Patient data were reviewed retrospectively. In total 59 CPE isolates were identified from 53 patients. Urine was the dominant clinical sample source (37%) and only 15% of the isolates were obtained from faecal screening. The majority of cases (62%) were directly associated with travel or hospitalization abroad, but both intra-hospital transmission and one inter-hospital outbreak were observed. The number of CPE cases/year was low (2–14 cases/year), but an increasing trend was observed. Klebsiella spp. (n = 38) and E. coli (n = 14) were the dominant species and blaKPC (n = 20), blaNDM (n = 19), blaOXA-48-like (n = 12) and blaVIM (n = 7) were the dominant carbapenemase gene families. The CPE isolates were genetically diverse except for K. pneumoniae where clonal group 258 associated with blaKPC dominated. All isolates were multidrug-resistant and a significant proportion (21%) were resistant to colistin. Interestingly, all blaOXA-48-like, and a large proportion of blaNDM-positive Klebsiella spp. (89%) and E. coli (83%) isolates were susceptible in vitro to mecillinam. Thus, mecillinam could have a role in the treatment of uncomplicated urinary tract infections caused by OXA-48- or NDM-producing E. coli or K. pneumoniae. In conclusion, the impact of CPE in Norway is still limited and mainly associated with travel abroad, reflected in the diversity of clones and carbapenemase genes