Author/Authors :
Fazeli Maryam نويسنده Department of Virology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran , Goudarzi Mehdi نويسنده Department of Pharmacology and Toxicology, Pharmacy School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran Goudarzi Mehdi , Rezaee Razieh نويسنده , Rashidi Nezhad Ramin نويسنده Infectious Diseases and Tropical Medicine Research Center,
Shahid Beheshti University of Medical Sciences, Tehran, IR
Iran , Meybodi Seyed Mansour نويسنده Department of Biology, Tonekabon Branch, Islamic Azad
University, Tonekanon, IR Iran
Abstract :
Background Staphylococcus aureus is an
important opportunistic pathogen and can cause a wide range of
infections. The ability of this pathogen to successfully persist within
the hospital and the community is largely due to its remarkable ability
to acquire resistance against various antimicrobial agents. Objectives
The aim of this study was to determine the carriage of antibacterial
resistance genes and virulence markers of S. aureus
isolates from hospitalized patients in intensive care units in Tehran,
the capital of Iran. Methods In this cross-sectional study that was
conducted during an 11-month period since March 2015 to January 2016, a
total of 105 S. aureus strains were investigated.
MRSA screening was performed by phenotypic and genotypic methods. The
Kirby-Bauer disk diffusion method was used to assess the sensitivity of
S. aureus strains. The strains were typed based on
the polymorphisms in SCCmec types. The presence of resistance
(ermA, ermB,
ermC, mupA,
msrA, msrB,
tetM, ant (4΄)-Ia,
aac (6΄)-Ie/aph (2˝),
aph (3΄)-IIIa) and toxin
(etb, eta, pvl,
tst) encoding genes were investigated by the
polymerase chain reaction (PCR) technique. Results In this study, 105
isolates of S. aureus were obtained from 299 various
clinical specimens. Ninety five (90.5%) strains were confirmed as
methicillin-resistant S. aureus. The lowest levels of
resistance were related to quinupristin-dalfopristin (16.8%) while the
highest levels of resistance were related to penicillin (94.7%).
Multi-drug resistance was observed in 91.5% of the isolates. Type IV was
the most prevalent SCCmec type (57.9%), followed by
type III (22.1), type V (12.6%), I (5.3%), and II (2.1%). Overall, 25
isolates (26.3%) harbored PVL-encoding genes, and all of them belonged
to SCCmec type IV. The presence of resistance genes
ant(4΄)-Ia,
aac(6΄)-Ie/aph(2˝),
aph(3΄)-IIIa,
ermA, ermB,
ermC, msrA,
msrB, and tetM was detected in
94.7%, 81.1%, 31.6%, 31.6%, 15.9%, 18.9%, 47.3%, 21.1%, 56.8%. The
frequency of the etb, eta, and
tst genes were 1.1%, 4.2%, and 32.6%, respectively.
Conclusions The results illustrated the diversity of antibacterial
resistance and virulence gene profiles among different
SCCmec types of S. aureus. The
increased prevalence of methicillin-resistant S.
aureus isolates containing different toxin and antibiotic
resistance genes is a serious threat for the hospitalized patients in
the intensive care units.
