Molecular Epidemiology of Carbapenem-Resistant Pseudomonas aeruginosa Clinical Strains Isolated from Western Algeria Between 2009 and 2012

Abstract

Infections caused by carbapenem-resistant Pseudomonas aeruginosa strains represent a major therapeutic and epidemiological problem. The aim of this study was to characterize carbapenem resistance in 89 clinical strains of P. aeruginosa isolated from three hospitals in western Algeria between October 2009 and November 2012. Minimum inhibitory concentrations (MICs) of imipenem were determined by the Etest method. Screening for metallo-β-lactamase (MβL) was performed using Etest MβL strips, and a PCR was conducted to detect carbapenemase-encoding genes. The amplification of the oprD gene followed by a sequencing reaction was performed for all strains resistant to imipenem. The clonality of 53 P. aeruginosa strains was demonstrated using multilocus sequence typing (MLST). Among the 89 isolates, 35 (39.33%) were found to be resistant to IMP (MICs ≥16 μg/ml). The blaVIM-2 gene was detected in two strains. The remaining imipenem-resistant isolates showed the presence of oprD mutations. The MLST analysis differentiated strains into various clones and the strains from the same clone had an identical sequence of the oprD gene. We report the second detection in 2010 of blaVIM-2 in Algerian P. aeruginosa strains. We also found that oprD mutations were the major determinant of high-level imipenem resistance. We demonstrate that these oprD mutations can be used as a tool to study the clonality in P. aeruginosa isolates.

Emergence of VIM-2 and IMP-15 Carbapenemases and Inactivation of oprD Gene in Carbapenem-Resistant Pseudomonas aeruginosa Clinical Isolates from Lebanon

“…MLST analysis showed that ST233 and ST235 described in western Mediterranean countries (20) are distinct in the phylogenetic tree, suggesting that there are two different successful epidemic clones present in the two sides of the Mediterranean basin. We also confirm our previous findings that oprD mutational group sequences can be used as a surrogate to MLST for typing isolates (21).…”

Real-time video imaging as a new and rapid tool for antibiotic susceptibility testing by the disc diffusion method: A paradigm for evaluating resistance to imipenem and identifying extended-spectrum β-lactamases

“…Molecular evidence in support of the resistance to carbapenems for the carbapenemase-producing bacteria was obtained by PCR and sequencing as previously reported [9,10].…”

“…AST was performed by the disc diffusion method on Mueller-Hinton agar (bioMérieux, Marcy-l'Étoile, France), and minimum inhibitory concentrations (MICs) for imipenem were determined using the Etest method (bioMérieux) as previously reported [10]. Isolates with an imipenem MIC of >8 g/mL and an inhibition zone diameter <17 mm were considered as imipenem-resistant, whereas a diameter ≥24 mm was considered indicative of imipenem susceptibility according to the Comité de l'antibiogramme de la Société Franç aise de Microbiologie (CA-SFM) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) [11].…”

First Detection of VIM-4-Producing Pseudomonas aeruginosa and OXA-48-Producing Klebsiella pneumoniae in Northeastern (Annaba, Skikda) Algeria

“…Several types of metallo-b-lactamases (MBLs) have been described around the world in P. aeruginosa isolates (IMP, VIM, SPM, GIM, SIM, AIM, FIM, and NDM). 4 The most frequent of the MBLs are the VIM types. These have been identified in carbapenem-resistant isolates of P. aeruginosa in European countries with coastlines on the Mediterranean basin: Italy, France, Greece, Spain, Croatia, and Turkey and from African countries: Tunisia, Kenya, Libya, South Africa, 4 and Lebanon.…”

“…4 The most frequent of the MBLs are the VIM types. These have been identified in carbapenem-resistant isolates of P. aeruginosa in European countries with coastlines on the Mediterranean basin: Italy, France, Greece, Spain, Croatia, and Turkey and from African countries: Tunisia, Kenya, Libya, South Africa, 4 and Lebanon. 5 The main porin for uptake of carbapenems in P. aeruginosa is the outer membrane protein, OprD.…”