The presence of Acinetobacter baumannii outside hospitals is still a controversial issue. The objective of our study was to explore the extrahospital epidemiology of A. baumannii in Lebanon. From February 2012 to October 2013, a total of 73 water samples, 51 soil samples, 37 raw cow milk samples, 50 cow meat samples, 7 raw cheese samples, and 379 animal samples were analyzed by cultural methods for the presence of A. baumannii. Species identification was performed by rpoB gene sequencing. Antibiotic susceptibility was investigated, and the A. baumannii population was studied by two genotyping approaches: multilocus sequence typing (MLST) and bla OXA-51 sequence-based typing (SBT). A. baumannii was detected in 6.9% of water samples, 2.7% of milk samples, 8.0% of meat samples, 14.3% of cheese samples, and 7.7% of animal samples. All isolates showed a susceptible phenotype against most of the antibiotics tested and lacked carbapenemase-encoding genes, except one that harbored a bla OXA-143 gene. MLST analysis revealed the presence of 36 sequence types (STs), among which 24 were novel STs reported for the first time in this study. bla OXA-51 SBT showed the presence of 34 variants, among which 21 were novel and all were isolated from animal origins. Finally, 30 isolates had new partial rpoB sequences and were considered putative new Acinetobacter species. In conclusion, animals can be a potential reservoir for A. baumannii and the dissemination of new emerging carbapenemases. The roles of the novel animal clones identified in community-acquired infections should be investigated.
Purpose. Streptococcus pneumoniae is a commensal bacterium that normally colonizes the human nasopharyngeal cavity. Once disseminated, it can cause several diseases, ranging from non-invasive infections such as acute otitis media and sinusitis through to invasive infections with higher mortality, including meningitis and septicaemia. Since the identification of the first S. pneumoniae strain with decreased susceptibility to penicillin in the 1960s, antibiotic resistance among S. pneumoniae has increased disturbingly and the mechanisms of resistance have begun to unfold.Methodology. This work briefly reviewed the available data on the molecular mechanisms underlying antimicrobial resistance and its epidemiology among pneumococcal strains in Middle Eastern countries.Key findings. Both intrinsic and acquired mechanisms (mutations, acquisition of novel mobile genetic elements and sometimes gene duplication and overexpression) affect susceptibility to a large variety of antibiotics. In Middle Eastern countries, including Lebanon, Iran, Saudi Arabia and Turkey, surveillance showed a disturbing increase in the strength and prevalence of resistance to antibiotics over the years, especially in the last decade. However, no surveillance reports were found in other Middle Eastern countries, such as Syria and Iraq.Conclusion. In order to better survey, control and prevent the emergence of multidrug-and extremely drug-resistant S. pneumoniae strains, antimicrobial stewardship, national surveillance and public awareness programmes should be developed urgently in Middle Eastern countries.
These findings show that Syria constitutes a reservoir for NDM-1-producing bacteria. These results also highlight the need for effective measures to stop the threatening spread of such strains.
The laboratory surveillance of bacillary dysentery is based on a standardised Shigella typing scheme that classifies Shigella strains into four serogroups and more than 50 serotypes on the basis of biochemical tests and lipopolysaccharide O-antigen serotyping. Real-time genomic surveillance of Shigella infections has been implemented in several countries, but without the use of a standardised typing scheme. Here, we study over 4000 reference strains and clinical isolates of Shigella, covering all serotypes, with both the current serotyping scheme and the standardised EnteroBase core-genome multilocus sequence typing scheme (cgMLST). The Shigella genomes are grouped into eight phylogenetically distinct clusters, within the E. coli species. The cgMLST hierarchical clustering (HC) analysis at different levels of resolution (HC2000 to HC400) recognises the natural population structure of Shigella. By contrast, the serotyping scheme is affected by horizontal gene transfer, leading to a conflation of genetically unrelated Shigella strains and a separation of genetically related strains. The use of this cgMLST scheme will facilitate the transition from traditional phenotypic typing to routine whole-genome sequencing for the laboratory surveillance of Shigella infections.
BackgroundA. baumannii has emerged as an important nosocomial pathogen with an outstanding ability to acquire multidrug resistant mechanisms. In this study, we investigate the molecular epidemiology and carbapenem resistance mechanisms of A. baumannii in Tripoli, Northern Lebanon.MethodsOne hundred sixteen non-duplicate isolates isolated between 2011 and 2013 in different hospitals in Tripoli, Lebanon from Lebanese patients and wounded Syrian patients during Syrian war were studied. Antibiotic susceptibility testing was determined by agar disc diffusion and Etest. Carbapenemase-encoding genes were investigated by PCR. All isolates were typed by blaOXA-51-like sequence based typing (SBT) and 57 isolates were also analysed by MLST using Pasteur’s scheme followed by eBURST analysis.ResultsOf the 116 isolates, 70 (60 %) showed a carbapenem resistance phenotype. The blaOXA-23 with an upstream insertion of ISAba1 was the major carbapenem resistance mechanism and detected in 65 isolates. Five isolates, including four from wounded Syrian patients and one from a Lebanese patient, were positive for blaNDM-1. blaOXA-51-like SBT revealed the presence of 14 variants, where blaOXA-66 was the most common and present in 73 isolates, followed by blaOXA-69 in 20 isolates. MLST analysis identified 17 sequence types (ST) and showed a concordance with blaOXA-51-like SBT. Each clonal complex (CC) had a specific blaOXA-51-like sequence such as CC2, which harboured blaOXA-66 variant, and CC1 harbouring blaOXA-69 variant. NDM-1 producing isolates belonged to ST85 (4 Syrian isolates) and ST25 (1 Lebanese isolate).ConclusionsOur results showed a successful predominance of international clone 2 with a widespread occurrence of OXA-23 carbapenemase in Lebanese hospitals. These findings emphasise the urgent need of effective measures to control the spread of A. baumannii in this country.
This study analyzed 42 Acinetobacter baumannii strains collected between 2009–2012 from different hospitals in Beyrouth and North Lebanon to better understand the epidemiology and carbapenem resistance mechanisms in our collection and to compare the robustness of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), repetitive sequence-based PCR (rep-PCR) and bla OXA-51 sequence-based typing (SBT). Among 31 carbapenem resistant strains, we have detected three carbapenem resistance genes: 28 carried the bla OXA-23 gene, 1 the bla OXA-24 gene and 2 strains the bla OXA-58 gene. This is the first detection of bla OXA-23 and bla OXA-24 in Lebanon. PFGE identified 11 types and was the most discriminating technique followed by rep-PCR (9 types), bla OXA-51 SBT (8 types) and MLST (7 types). The PFGE type A'/ST2 was the dominant genotype in our collection present in Beyrouth and North Lebanon. The clustering agreement between all techniques was measured by adjust Wallace coefficient. An overall agreement has been demonstrated. High values of adjust Wallace coefficient were found with followed combinations: PFGE to predict MLST types = 100%, PFGE to predict bla OXA-51 SBT = 100%, bla OXA-51 SBT to predict MLST = 100%, MLST to predict bla OXA-51 SBT = 84.7%, rep-PCR to predict MLST = 81.5%, PFGE to predict rep-PCR = 69% and rep-PCR to predict bla OXA-51 SBT = 67.2%. PFGE and MLST are gold standard methods for outbreaks investigation and population structure studies respectively. Otherwise, these two techniques are technically, time and cost demanding. We recommend the use of bla OXA-51 SBT as first typing method to screen isolates and assign them to their corresponding clonal lineages. Repetitive sequence-based PCR is a rapid tool to access outbreaks but careful interpretation of results must be always performed.
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