Les Proteus incriminés dans les infections communautaires et hospitalières

Abstract

Proteus, Morganella and Providencia (PMP) are a major cause of bacterial infections causing primary and secondary infections. Epidemiological data on PMP isolates in clinical specimens and their antimicrobial sensitivity testing is important to help clinicians in the empirical selection of medications. Here we performed characterization of PMP clinical isolates using the API 20E system and Bruker MALDI Biotyper 2.0 (MALDI-TOF/MS) platforms for microbial identification. Diagnostic accuracy was determined by independent comparison of each method to phylogenetic analysis based on the 16S rDNA gene sequencing. This study was designed also to evaluate the emergence of multidrug resistance and the prevalence of extended-spectrum β-lactamases (ESBLs), carbapenemases, aminoglycoside-modifying enzymes and resistance to fluoroquinolones among 110 PMP strains that were isolated from a large variety of clinical specimens at University Hospital of Constantine in Algeria. The Api 20E system correctly identified 92.59% to the species level, while, the Bruker Biotyper correctly identified 99.05% isolates to the species level, in comparison with the 16S rDNA gene sequencing. MALDI-TOF MS identifications became concordant with 16S rDNA gene results for all strains except for one strain identified correctly to the genus level only. Antibiotic susceptibility testing was performed on all PMP clinical isolates, and presence of antibiotic resistance genes was screened for by PCR amplification and sequencing. 65.45 % of the strains (72 isolates) were positive for different antibiotic resistance encoding genes: blaCTX-M-15, blaTEM-1, blaTEM-2, blaPER-1, blaSHV-11, aadA1, aadA2, armA, aac(6′)-Ib, aac(6′)-Ib-cr, aac(3)-Ia, ant(2″)-I, and forming different profiles. Moreover, the blaOXA-24 gene was detected in the imipenem-resistant strain. In this study, we found for the first time in Algeria a multidrug resistant P. mirabilis isolates harboring blaOXA-24, armA 16S rDNA methylase and aac(6)-Ib-cr gene.