Detection of blaSPM-1 Metallo-?-Lactamase Gene in Imipenem-Resistant Pseudomonas aeruginosa Strains Isolated From Hospitalized Patients in Isfahan Hospitals

authors:

avatar Mansour Sedighi 1 , avatar Amir Hasanzadeh 2 , avatar Saeid Safiri 3 , avatar Naeema Syedi 4 , avatar Shayan Mostafaei 5 , avatar Jamshid Faghri 6 , *

Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, IR Iran
Division of Microbiology, Department of Pathobiology, School of Public Health and Institute of Public Health Research, Tehran University of Medical Sciences, Tehran, IR Iran
Department of Public Health, School of Nursing and Midwifery, Maragheh University of Medical Sciences, Maragheh, IR Iran
School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, Australia
Department of Epidemiology and Biostatistics, School of Public Health, Isfahan University of Medical Sciences, Isfahan, IR Iran
Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IR Iran

how to cite: Sedighi M, Hasanzadeh A, Safiri S, Syedi N, Mostafaei S, et al. Detection of blaSPM-1 Metallo-?-Lactamase Gene in Imipenem-Resistant Pseudomonas aeruginosa Strains Isolated From Hospitalized Patients in Isfahan Hospitals. J Arch Mil Med. 2015;3(2):26977. doi: 10.5812/jamm.3(2)2015.26977.

Abstract

Background:

Pseudomonas aeruginosa is an opportunistic human pathogen, which causes serious problems especially in people who have immunodeficiency. Recently, metallo-?-lactamase (MBLs) resistance in this bacterium has led to some difficulties in treating bacterial infections. The blaSPM-1 is one of the MBL gene families, which induces resistance to the carbapenem class antibiotics; this gene has not been previously assessed in Iran.

Objectives:

Detection and quantification of blaSPM-1- metallo-?-lactamase gene among resistant Pseudomonas aeruginosa strains (imipenem), isolated from patients in Isfahan hospitals.

Patients and Methods:

A total of 180 samples were isolated from various nosocomial infections. These isolates were identified as Pseudomonas aeruginosa by using biochemical tests. In order to determine their bacterial drug resistance-pattern the Kirby-Bauer disk diffusion method was utilized. Presence of MBLs in imipenem isolates was detected using the combine disk technique (IMP-EDTA). Similarly, an E-test on Mueller-Hinton agar was used to determine the minimal inhibitory concentration (MIC) of imipenem isolates. The imipenem isolates were then subjected to polymerase chain reaction (PCR) to detect the blaSPM-1 gene. Data were analyzed using the SPSS software (version 16, SPSS Inc., Chicago, IL, USA).

Results:

In total, 96 isolates of Pseudomonas aeruginosa were collected. Of all isolates, 34 (35.41%) were found to be imipenem-resistant P. aeruginosa. The MIC levels in all imipenem-resistant strains were MIC ? 32 ?g/mL. Thirteen (38.23%) of the imipenem-resistant P. aeruginosa isolates were MBL positive. None of the isolates carried the blaSPM-1 gene, as indicated by the PCR assay.

Conclusions:

The rate of imipenem resistance due to MBL has increased dramatically. Early detection and infection-control practices are the best antimicrobial strategy for this organism.

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