Characterization of Cephalosporinases Produced by Clinical Isolates of Enterobacteriacae in North Lebanon

Background: The problem of Enterobacteriacae resistance to β-Lactamase drugsis of growing concern in hospitals. Enterobacteria have developed multiple mechanismsof resistance to antibiotics, the main one is the enzymatic resistance mediatedby the beta-lactamases. This study aims to characterize the occurrence ofcephalosporinases in clinical isolates of Enterobacteriacae isolates in North Lebanon.Methods. Twenty two strains of Enterobacteriacae producing high level of cephalosporinaseshave been studied. The antibiotic susceptibility of each strain wastested on Mueller Hinton agar contains cloxacilline (250 mg/L) and by using E-testaccording the guidelines of the Antibiogram Committee of the French Society forMicrobiology. The search for plasmid-mediated cephalosporinases was performedusing PCR and primers for plasmid-mediated cephalosporinases genes (CMY-2,DHA-1, ACT-1, ACC-1, FOX-1 and MOX-1).Results: Thirteen positive strains were detected, of these 9 strains produced theplasmid-mediated cephalosporinase (CMY-2) and one strain produced the plasmidmediatedcephalosporinase (DHA-1). The remaining 9 strains were high-level chromosomalcephalosporinase producers since they belong to group-three Enterobacteria.They did neither produce plasmid-mediated cephalosporinase, nor did theyhave resistance to third generation cephalosporins except for cefepim. Two strains(CMUL E. coli 021) and CMUL E. coli 255) which were not susceptible for cefepim byE-test produced plasmid-mediated cephalosporinase The sequencing result of these2 E.coli strains did not show any mutation in the promoter that is responsible forhigh expression level of the chromosomal cephalosporinase. All examined strainsproducing plasmid-mediated cephalosporinase CMY-2 were analyzed by ERIC-PCRtechnique. The results showed that two of these strains had the same pattern (C4and C5) and three others had another pattern (C10, C12 and C13).Conclusion: This study shows the variations of cephalosporinases produced byclinical isolates of Enterobacteriacae in North Lebanon

Antimicrobial Resistance in Escherichia coli

Multidrug resistance in Escherichia coli has become a worrying issue that is increasingly observed in human but also in veterinary medicine worldwide. E. coli is intrinsically susceptible to almost all clinically relevant antimicrobial agents, but this bacterial species has a great capacity to accumulate resistance genes, mostly through horizontal gene transfer. The most problematic mechanisms in E. coli correspond to the acquisition of genes coding for extended-spectrum β-lactamases (conferring resistance to broad-spectrum cephalosporins), carbapenemases (conferring resistance to carbapenems), 16S rRNA methylases (conferring pan-resistance to aminoglycosides), plasmid-mediated quinolone resistance (PMQR) genes (conferring resistance to [fluoro]quinolones), and mcr genes (conferring resistance to polymyxins). Although the spread of carbapenemase genes has been mainly recognized in the human sector but poorly recognized in animals, colistin resistance in E. coli seems rather to be related to the use of colistin in veterinary medicine on a global scale. For the other resistance traits, their cross-transfer between the human and animal sectors still remains controversial even though genomic investigations indicate that extended- spectrum β-lactamase producers encountered in animals are distinct from those affecting humans. In addition, E. coli of animal origin often also show resistances to other—mostly older—antimicrobial agents, including tetracyclines, phenicols, sulfonamides, trimethoprim, and fosfomycin. Plasmids, especially multiresistance plasmids, but also other mobile genetic elements, such as transposons and gene cassettes in class 1 and class 2 integrons, seem to play a major role in the dissemination of resistance genes. Of note, coselection and persistence of resistances to critically important antimicrobial agents in human medicine also occurs through the massive use of antimicrobial agents in veterinary medicine, such as tetracyclines or sulfonamides, as long as all those determinants are located on the same genetic elements

Study of the molecular mechanism of antibiotic resistance in the mediterranean basin

La détection, la surveillance et la diffusion de la résistance des bactéries aux antibiotiques est un enjeu majeur au niveau mondial depuis la découverte et la diffusion de bactéries multi résistantes, en particulier la résistance aux carbapénèmes, spécifiquement chez les Entérobactéries et les bactéries du genre Pseudomonas et Acinetobacter. L’émergence et la dissémination des pathogènes Gram- résistants aux carbapénèmes est un contributeur significatif de la morbidité et la mortalité du patient. Malgré les efforts radicaux dans le contrôle de l’infection et les améliorations dans le diagnostique moléculaire, les bacilles Gram- résistants aux carbapénèmes demeurent une formidable menace vue que quelques agents antimicrobiens sont actifs et très peu devraient être disponibles dans le futur proche.L’origine et la source des gènes de résistance dans le monde sont mal connues et des travaux récents suggèrent que les animaux domestiques et sauvages, l’environnement mais également le tube digestif des mammifères et des humains pourraient représenter un réservoir et une source importante de gènes de résistance susceptibles d’être transmissibles à l’homme. C’est dans cette optique que ce projet de thèse s’articule avec comme objectifs : (i) la réalisation d’études épidémiologiques moléculaires d’isolats cliniques et animales résistants aux carbapénèmes isolés dans le basin Méditerranéen et la caractérisation des supports moléculaires de cette résistance ; (ii) la description de nouveaux mécanismes de résistance a l’imipenème ; et enfin (iii) le séquençage de génomes d’isolats cliniques résistants aux carbapénèmes et l’analyse de ces derniers.The detection, monitoring and dissemination of bacterial resistance to antibiotics are a major issue worldwide since the discovery and spread of multi-resistant bacteria, in particular resistance to carbapenems, specifically among Enterobacteriaceae and bacteria of the genus Pseudomonas and Acinetobacter.The emergence and dissemination of carbapenem-resistant Gram-negative pathogens is a significant contributor to patient morbidity and mortality. Despite radical efforts in infection control and improvements in molecular diagnostics, carbapenem-resistant Gram-negative bacilli remain a formidable threat as few antimicrobial agents are reliably active and very little is expected to be available in the near future.The origin and source of resistance genes in the world are not well known and recent works suggest that domestic and wild animals, the environment (soil, water, rivers ..) but also the digestive tract of mammals and humans could represent a reservoir and an important source of resistance genes that may be transmissible to humans.It is in this context that this thesis project articulates with the following objectives: (i) The achievement of molecular epidemiological studies on carbapenem-resistant clinical and animal isolates collected from countries in the Mediterranean basin (Lebanon, Libya, France) and the characterization of the genetic determinants of this resistance; (ii) the description of new resistance mechanisms to imipenem; and finally (iii) The genome sequencing of clinical isolates resistant to carbapenems, the analysis of these genomes and the identification of mechanisms and genetic supports of the resistance to carbapenems and other antibiotics

First detection of insertion sequence element ISPa1328 in the oprD porin gene of an imipenem-resistant Pseudomonas aeruginosa isolate from an idiopathic pulmonary fibrosis patient in Marseille, France

AbstractWe report here the first case of a carbapenem-resistant Pseudomonas aeruginosa clinical isolate harboring the insertion sequence (IS) element ISPa1328 in the oprD gene in an idiopathic pulmonary fibrosis patient in France previously treated with imipenem

Prevalence and emergence of carbapenemases-producing Gram-negative bacteria in Mediterranean basin

International audienceThe emergence and the global spread of carbapenemases concern to health services worldwide. Their celestial rise among Gram-negative bacilli has challenged both the scientific and pharmaceutical sectors. Indeed, infections caused by these bacteria have limited treatment options and have been associated with high mortality and morbidity rates. Carbapenemase producers are mainly identified among Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii and still mostly in hospital settings and rarely in the community. They are closely related to KPC, VIM, IMP, NDM, and OXA-48 types. The encoding genes are mostly plasmid located and associated with various mobile genetic elements. The Mediterranean area is of interest due to a great diversity and population mixing. The prevalence of carbapenemases is particularly high and variant among countries, partially depending on the population exchange relationship between the regions and the possible reservoirs of each carbapenemase. This review described the epidemiology of carbapenemases in this region of the world highlighting the worrisome situation and the need to screen and detect these enzymes to prevent and control their dissemination especially as it is clear that very few novel antibiotics will be introduced in the next few years, making the dissemination of carbapenem-resistant Gram-negative bacteria of crucial importance worldwide

Molecular characterisation of extended-spectrum beta-lactamase- and plasmid AmpC-producing Escherichia coli strains isolated from broilers in Bejaia, Algeria

International audienceThis study aimed to characterise the molecular support of antibiotic resistance in expanded-spectrum cephalosporin (ESC)-resistant Escherichia coli isolates recovered from healthy broilers in Bejaia, northeast Algeria. A total of 61 intestinal swabs from slaughtered broilers from four regions in Bejaia locality, Algeria, were collected between February and April 2014, from which 20 ESC-resistant E. coli strains were isolated. Escherichia coli isolates were identified by classical biochemical and MALDI-TOF methods. Antibiotic susceptibility testing was performed using disk diffusion and Etest methods. Screening for beta-lactamases, aminoglycoside-modifying enzyme (AME)-encoding genes and qnr determinants was performed by PCR and sequencing. Clonal relatedness was determined using molecular typing by multilocus sequence typing (MLST). Antibiotic susceptibility testing revealed that the isolates showed high rates of resistance (>90%) to amoxicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam, aztreonam, ceftazidime, streptomycin, tobramycin, nalidixic acid and ciprofloxacin. Low rates of resistance were observed for kanamycin (35%), amikacin (30%), cefoxitin (20%) and cefotaxime (15%). Molecular characterisation revealed that all of the isolates expressed the bla(TEM-1) gene. Fourteen of them harboured the bla(SHV-12) gene, two harboured the bla(CTX-M-1) gene and four isolates harboured bla(CMY-2). Screening for AME-encoding genes demonstrated that all isolates contained the aadA gene. In addition, qnrA was detected as the quinolone resistance determinant in 13 isolates. MLST revealed four known sequence types (STs), including ST744, ST38, ST1011 and ST2179, as well as one new sequence type (ST5086). Here we report the first study describing the clonal diversity of extended-spectrum beta-lactamase (ESBL)- and plasmid AmpC-producing E. coli isolated from healthy broilers in Algeria. (C) 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved

Bacterial infection during wars, conflicts and post-natural disasters in Asia and the Middle East: a narrative review

International audienc

First Detection of Colistin-Resistant Klebsiella pneumoniae in Association with NDM-5 Carbapenemase Isolated from Clinical Lebanese Patients

International audienc