Author/Authors :
Rahimi Fateh نويسنده , Bouzari Majid نويسنده Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan , Komijani Majid نويسنده Department of Biology, Faculty of Sciences, University of
Isfahan, Isfahan, IR Iran
Abstract :
Background Approximately 80% of nosocomial infections are caused
by strains of Klebsiella pneumoniae. Resistance to
β-lactam antibiotics is a result of expression of extended-spectrum
β-lactamase (ESBL) genes. Recently, phage therapy has gained increasing
attention due to its many advantages over chemotherapy. Objectives The
aim of this study was to isolate ESBL-positive Klebsiella
pneumoniae strains from different types of wounds, and a lytic
bacteriophage against them. Methods During a two-year period from
January 2013 to February 2015, in a cross-sectional study, 41
K. pneumoniae strains were isolated from 193
categories of infected wounds at three hospitals in Isfahan, Iran.
Phenotypic and genotypic methods were used to detect the ESBL-positive
strains. A lytic phage against K. pneumoniae was
isolated, and its host range, morphology, thermal and pH stability,
saline stress, and estimated genome size were determined. Results Of the
41 K. pneumoniae isolates, 18 were ESBL-producing and
36 carried antibiotic-resistance genes. A total of 36 out of 41 isolated
samples carried one or more resistance genes. The results showed that
the differences between phenotypic and genotypic identification methods
were significant (P = 0.0001). The SHV,
CTX-M, and TEM genes were detected
in 29, 10, and 9 isolates of the tested bacteria, respectively. No
bacteria contained both the SHV and the
CTX-M genes. The frequency of the
SHV gene was significantly higher than that of the
other genes (P = 0.0001). The phage’s morphology features placed it in
the Myoviridae family. Only 38 out of 41 clinical
isolates were susceptible to the phage. Phage titers were completely
preserved after one hour of incubation at 30°C and 40°C, and they were
stable at different pH values. The phage’s survival decreased when the
salt concentration was increased. Conclusions The high rate of isolation
of antibiotic-resistant strains of K. pneumoniae was
consistent with other studies. As the phage was virulent and specific
for K. pneumoniae, and was stable and active at
different pH values, salt concentrations, and temperatures, its
application in phage therapy of infected wounds is suggested.