Spread of extended-spectrum β-lactamase genes of blaOXA-10, blaPER-1 and blaCTX-M in Pseudomonas aeruginosa strains isolated from burn patients.
BACKGROUND
Pseudomonas aeruginosa is resistant to many antibiotics due to production of different classes of extended spectrum β-lactamases (ESBLs). Prevalence of ESBLs among P. aeruginosa has been increased in recent years, demonstrate a serious health problem especially in burn units worldwide.


OBJECTIVE
Present study was designed to determine the ESBL producing strains and identify the genes encoding three different ESBLs of bla PER-1, bla OXA-10 and bla CTX-M genes in P. aeruginosa isolates from burn patients.


METHODS
In total 185 clinical isolates of P. aeruginosa were collected from infectious wounds of hospitalized burn patients. Antimicrobial susceptibility testing and phenotypic detection of ESBL were performed by disk diffusion method and Double disk Synergy Test (DDST). Polymerase Chain Reaction (PCR) was done for detection of bla OXA-10, bla PER-1 and bla CTX-M ESBL encoding genes.


RESULTS
In total, 176 (95.13%) isolates were multidrug resistant. The DDST demonstrated 96 (51.9%) isolates as putative ESBL producers with 100% or highly resistance to ofloxacin, cephalexin, aztreonam (97.57%) and ceftriaxone (91.6%). By PCR amplification, bla PER-1, bla OXA-10 and bla CTX-M genes were detected in 52 (54.16%), 66 (68.75%) and 1 (1.04%) isolates of ESBL producers respectively. Forty-three isolates (44.79%) were simultaneously positive for both bla OXA-10 and bla PER-1 related genes.


CONCLUSIONS
The rate of ESBL producing P. aeruginosa was notable in present study. Since there are only limited effective antibiotics against the bacterium, therefore all isolates must be investigated by antimicrobial susceptibility testing, which limits resistance development in burn units and helps the management of treatment strategy.
Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Zahra
Z
Farshadzadeh
Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Electronic address: azarkhosravi69@gmail.com.
Azar Dokht
AD
Khosravi
Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Seyed Mohammad
SM
Alavi
Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Najmeh
N
Parhizgari
Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Hajar
H
Hoveizavi
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins; D002056:Burns / Q000382:microbiology*; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases; C000600039:beta-lactamase blaCTX-M, Pseudomonas aeruginosa; C000600037:beta-lactamase blaOXA-10, Pseudomonas aeruginosa; C000600038:beta-lactamase blaPER-1, Pseudomonas aeruginosa
Burn; DDST; ESBL producing; P. aeruginosa; PCR