Spa Typing of Staphylococcus aureus Strains Isolated From Clinical Specimens of Patients With Nosocomial Infections in Tehran, Iran.
BACKGROUND
The incidence of nosocomial Staphylococcus aureus infection is increasing annually and becoming a true global challenge. The pattern of Staphylococcus aureus protein A (spa) types in different geographic regions is diverse.


OBJECTIVE
This study determined the prevalence of methicillin-resistant S. aureus and different spa types in S. aureus clinical isolates.


METHODS
During a six-month period, 90 S. aureus isolates were recovered from 320 clinical specimens. The in vitro susceptibility of various S. aureus isolates to 16 antibiotic discs was assessed using the Kirby-Bauer disk diffusion method. Molecular typing was carried out with S. aureus protein A typing via polymerase chain reaction.


RESULTS
The frequency of methicillin-resistant S. aureus in our study was 88.9%. Twenty-three (25.5%) isolates were positive for panton-valentine leukocidin encoding genes. S. aureus presented a high resistance rate to ampicillin (100%) and penicillin (100%). No resistance was observed to vancomycin, teicoplanin, or linezolid. The rates of resistance to the majority of antibiotics tested varied between 23.3% and 82.2%. The rate of multidrug resistance among these clinical isolates was 93.3%. The 90 S. aureus isolates were classified into five S. aureus protein A types: t037 (33.3%), t030 (22.2%), t790 (16.7%), t969 (11.1%), and t044 (7.7%). Eight (8.9%) isolates were not typable using the S. aureus protein A typing method.


CONCLUSIONS
We report a high methicillin-resistant S. aureus rate in our hospital. Additionally, t030 and t037 were the predominant spa-types among hospital-associated S. aureus. Our findings emphasize the need for continuous surveillance to prevent the dissemination of multidrug resistance among different S. aureus protein A types in Iran.
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
Mehdi
M
Goudarzi
WHO Collaborating Center for Reference and Research on Rabies, Pasteur Institute of Iran, Tehran, IR Iran.
Maryam
M
Fazeli
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
Hossein
H
Goudarzi
Department of Medical laboratory Sciences, School of Paramedicine, Qazvin University of Medical Sciences, Qazvin, IR Iran.
Mehdi
M
Azad
Department of Medical Mycology, Pasteur Institute of Iran, Tehran, IR Iran.
Sima Sadat
SS
Seyedjavadi
Methicillin-Resistant Staphylococcus aureus (MRSA); Nosocomial Infection Staphylococcus aureus; Spa Typing
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