Molecular epidemiology and carbapenem resistance mechanisms in Acinetobacter baumannii strains isolated from different environments in Lebanon

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Extra-human epidemiology of Acinetobacter baumannii in Lebanon

Presence of Acinetobacter baumannii outside hospitals is still a controversial issue. The objective of our study was to explore the extra hospital 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 analysed by cultural methods for the presence of A. baumannii. Species identification was performed by rpoB gene sequencing. Antibiotic susceptibility was investigated and A. baumannii population was studied by two genotyping approaches: Multilocus Sequence Typing (MLST) and blaOXA-51 Sequence-Based Typing (blaOXA-51 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 harboured a blaOXA-143 gene. MLST analysis revealed the presence of 36 sequence types (ST), among them 24 were novel ST(s), reported for the first time in this study. blaOXA-51 SBT showed the presence of 34 variants, among them 21 were novel and all isolated from animal origin. Finally, 30 isolates had new partial rpoB sequences and were considered as putative new Acinetobacter species. In conclusion, animals can be a potential reservoir for A. baumannii and the dissemination of new emerging carbapenemases. The role of novel identified animal clones in community-acquired infections should be investigated

Identification and Characterisation of Pseudomonas 16S Ribosomal DNA from Ileal Biopsies of Children with Crohn's Disease

Molecular analysis of bacterial 16S rRNA genes has made a significant contribution to the identification and characterisation of bacterial flora in the human gut. In particular, this methodology has helped characterise bacterial families implicated in the aetiology of inflammatory bowel disease (IBD). In this study we have used a genus specific bacterial 16S PCR to investigate the prevalence and diversity of Pseudomonas species derived from the ileum of children with Crohn's disease (CD), and from control children with non-inflammatory bowel disease (non-IBD) undergoing their initial endoscopic examination. Fifty eight percent of CD patients (18/32) were positive using the Pseudomonas PCR, while significantly fewer children in the non-IBD group, 33% (12/36), were PCR positive for Pseudomonas (p<0.05, Fischer's exact test). Pseudomonas specific 16S PCR products from 13 CD and 12 non-IBD children were cloned and sequenced. Five hundred and eighty one sequences were generated and used for the comparative analysis of Pseudomonas diversity between CD and non-IBD patients. Pseudomonas species were less diverse in CD patients compared with non-IBD patients. In particular P.aeruginosa was only identified in non-IBD patients

Analysis of the virulence characteristics of three new species of the genus Pseudomonas isolated from Lebanese spring waters

Three new species of the genus Pseudomonas (P. libanensis, P. cedrella, and P. orientalis) isolated from 3 important Lebanese spring waters (Kadicha, Kassam and Mar-Sarkis) in northern Lebanon that feed 45% of the total Lebanese population, were studied for their in vitro virulence factors. We have studied the adhesion, invasion and cytotoxicity properties in HEP-2 cells culture, the production for the following enzymes: proteinase, gelatinase, lipase, lecithinase, DNAse, coagulase, hyaluronidase, chondroitinase, hemolysin, elastase and fibrinolysin, and the acid lability test. All these properties have been studied at 37°C. Two of the P. libanensis strains were cytotoxic, but none of the P. cedrella and P. orientalis strains presents an invasive, adhesive or cytotoxic characters. These new species did not produce a significant enzymes associated with virulence, were not acid resistant

Sensibilité à 23 antibiotiques de 83 souches de Aeromonas hydrophila isolées d'eaux libanaises

Quatre-vingt-trois souches de Aeromonas hydrophila sont isolées de l'environnement aquatique au Liban. Après identification des souches par le système API-20E (bioMérieux - France), la sensibilité vis-à-vis de 23 antibiotiques a été déterminée. L'étude a montré que les souches étaient résistantes à 100 % à l'Amoxicilline. L'Acide Clavulanique n'a restauré l'activité de cette molécule que chez 26,5 % des souches. La sensibilité à la Ticarcilline était de l'ordre de 32,53 %. Deux souches étaient productrice de bêta-lactamases à spectre élargi (BLSE). Plusieurs profils de résistance ont été constatés, le profil le plus important était Amoxicilline + Amoxicilline-Acide Clavulanique + Ticarcilline + Céphalexine

Antibiotic susceptibility, serotyping and determination of minimum inhibitory concentrations of imipenem and meropenem in relation to 88 strains of Pseudomonas aeruginosa isolated in northern Lebanon

ABSTRACT We studied the susceptibility of 88 non-repetitive clinical isolates of Pseudomonas aeruginosa by the agar diffusion method. Serotyping of the strains is determined by the slide agglutination technique using specific antisera, polyvalent and monovalent. The minimum inhibitory concentration (MIC) of imipenem and meropenem was determined by the E-test method. Finally we analyzed the different resistance phenotypes observed in the study. The results obtained from infected sites revealed the predominance of broncho-alveolar secretions (N* = 30, P** = 34.1%), followed by urine samples (N = 23, P = 26.1%).The results of serotyping showed that serotype O11 was the most common (N = 14, P = 16%) followed by serotype O7 (N = 11, P = 12.5%) and serotype O2 (N = 10, P = 11.36%). The strains isolated in broncho-alveolar secretions were the most resistant to antibiotics. The level of susceptibility of 88 strains to ticarcillin and ticarcillin-clavulanate was 66% and 67.1% respectively. The susceptibility to Piperacillin and Piperacillin - Tazobactam was 72.73% and 80.7% respectively. With regard to carbapenems, we tested imipenem and meropenem and the susceptibility was 78.4% and 87.51% respectively. Regarding anti-pyocyanic cephalosporins, we observed that the susceptibility to ceftazidim was 77.37% and that of Cefepim was 80.67%.Susceptibility to aminoglycosides showed good activity for amikacin with an 87.53% susceptibility. By analyzing the MIC values obtained, we observed that for sensitive strains, values of meropenem were lower than those for imipenem.Five strains had intermediate susceptibility to imipenem while they were sensitive to meropenem. Finally 14 strains were resistant to imipenem whereas only 9 were resistant to meropenem. By analyzing the different resistance phenotypes observed in this study, we can report that there were 50 different resistance phenotypes.Based on these results, we concluded that the major phenotype observed was the phenotype of resistance to fosfomycin (13 strains). There was one isolated resistance phenotype to imipenem (one strain) and another strain that showed an intermediate susceptibility phenotype to this antibiotic. * N: Number of strains** P: Percentag