Staphylococcus aureus Isolates Carrying Panton-Valentine Leucocidin Genes: Their Frequency, Antimicrobial Patterns, and Association With Infectious Disease in Shahrekord City, Southwest Iran.
BACKGROUND
A diversity of virulence factors work together to create the pathogenicity of Staphylococcus aureus. These factors include cell surface components that promote adherence to surfaces as well as exoproteins such as Panton-Valentine leukocidin (PVL), encoded by the luk-PV genes, that invade or bypass the immune system and are toxic to the host, thereby enhancing the severity of infections caused by methicillin-resistant Staphylococcus aureus (MRSA).


OBJECTIVE
The aim of this study was to determine the frequency of PVL-positive MRSA strains by real-time PCR and their antibiotic susceptibility patterns by phenotypic test.


METHODS
In total, 284 Staphylococcus isolates, identified by phenotypic methods from clinical samples of Shahrekord University Hospitals, Shahrekord, Iran, were tested for nuc, mecA, and PVL genes by TaqMan real-time PCR. The antibiotic susceptibility patterns of PVL-containing MRSA strains were determined via the disk diffusion method.


RESULTS
In total, 196 isolates (69%) were nuc positive (i.e., S. aureus); of those isolates, 96 (49%) were mecA positive (MRSA). Eighteen (18.8%) of the 96 MRSA positive and 3 (3%) of the 100 methicillin-susceptible Staphylococcus aureus (MSSA) strains were PVL positive. PVL-positive MRSA strains were mostly recovered from tracheal specimens. Eight PVL-positive MRSA strains were resistant to all the tested antibiotics except vancomycin. A significant correlation (P = 0.001) was found between the mecA positivity and the presence of luk-PV genes.


CONCLUSIONS
Community acquired (CA)-MRSA is becoming a public health concern in many parts of the world, including Asian countries. The variable prevalence of luk-PV-positive MRSA isolates in different regions and their rather high frequency in pneumonia necessitate the application of rapid diagnostic methods such as real-time PCR to improve treatment effectiveness.
Department of Molecular Medicine, Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, IR Iran.
Laleh
L
Shariati
Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran.
Majid
M
Validi
Department of Nursing, School of Nursing and Midwifery, Shahrekord University of Medical Sciences, Shahrekord, IR Iran.
Ali Mohammad
AM
Hasheminia
Department of Parasitology and Mycology, School of Medicine, Arak University of Medical Sciences, Arak, IR Iran.
Reza
R
Ghasemikhah
Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IR Iran.
Fariborz
F
Kianpour
Department of Microbiology and Immunology, Cellular and Molecular Research Center, Shahrekord University of Medical Sciences, Shahrekord, IR Iran.
Ali
A
Karimi
Department of Microbiology and Immunology, Cellular and Molecular Research Center, Shahrekord University of Medical Sciences, Shahrekord, IR Iran.
Mohammad Reza
MR
Nafisi
Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IR Iran; Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, IR Iran.
Mohammad Amin
MA
Tabatabaiefar
Infectious Disease; Iran; Methicillin-Resistant Staphylococcus aureus; Panton-Valentine leukocidin; Real-Time PCR