Clonal diversity and genomic characterization of Panton-valentine Leukocidin (PVL)-positive Staphylococcus aureus in Tehran, Iran

Abstract

Background Some Staphylococcus aureus strains produce Panton-Valentine leukocidin (PVL), a bi-component pore-forming toxin, which causes leukocyte lysis and tissue necrosis. Currently, there is very limited information on the molecular epidemiology of PVL-encoding S. aureus strains in Iran. This study aimed to determine the molecular epidemiology and genetic background of PVL-positive S. aureus clinical strains isolated from Iranian patients. Methods A total of 28 PVL-positive S. aureus strains were detected from 600 S. aureus isolates between February 2015 and March 2018 from different hospitals in Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Molecular genotyping was performed using SCCmec and accessory gene regulator (agr) typing, PVL haplotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Results The highest antibiotic resistance rate was found to be against erythromycin (57.1%), followed by ciprofloxacin (42.8%) and clindamycin (35.7%). Moreover, 19 (67.9%) out of 28 S. aureus isolates were identified as MRSA, including CA-MRSA (14/19, 73.7%) and HA-MRSA (5/19, 26.3%). SCCmec type IVa was detected as the predominant type (10/19, 52.6%), followed by type III (5/19, 26.3%) and type V (4/19, 21.1%). The agr type I was identified as the most common type (14/28, 50%), and H and R haplotype groups were observed at frequencies of 67.9 and 32.1%, respectively. Among H variants, the predominant variant was H2 (78/9%). The isolates encompassed 21 different sequence types (STs), including 16 new STs (ST5147 to ST5162). Based on eBURST analysis, the isolates were clustered into five CCs, including CC30, CC22, CC1, CC8, and CC5 (ST5160), and nine singletons. PFGE typing showed that 24 isolates were clustered into A (4 pulsotypes), B (9 pulsotypes), and C (11 pulsotypes) clusters. Conclusions A high prevalence of PVL-positive CA-MRSA strains was detected in Iran. The majority of PVL-positive isolates were of H (mostly H2) variant, while R variant was harbored by 100% of PVL-positive MRSA strains. Also, CC8, CC22, and CC30 were identified as the dominant clones among PVL-encoding S. aureus strains. This study promotes a better understanding of the molecular epidemiology and evolution of PVL-positive S. aureus strains in Iran.

Determining the Molecular Identity of Two Virulence Genes mec-A and lukS/F-PV of Staphylococcus aureus Isolated From the Lung Secretions of Patients Admitted to Intensive Care Units in Kerman, Iran

“…Based on the results of the first comprehensive study by Najafi Olya et al, investigating the clonal diversity and genomic characteristics of positive S. aureus (PVL) in Iran, it was determined that PVL-positive MRSA strains are highly prevalent in Iran. The results of this study, compared to those of the present study, on the prevalence of methicillin-resistant S. aureus and the mec-A gene, lukS/ FPV, may contribute to the understanding of molecular epidemiology and evolution (15). In a study by Trevizani Rocchetti et al, out of 85 samples (23.0%) of blood cultures, S. aureus and CoNS were detected in 286 samples (77.0%).…”

Prevalence of panton–Valentine leukocidin and toxic shock syndrome toxin-1 genes in methicillin-resistant Staphylococcus aureus isolated from nose of restaurant workers in Kirkuk city

“…All isolates were also sensitive to gentamicin and chloramphenicol at 100%, whereas they were resistant to clindamycin, erythromycin, and tetracycline with percentages of 35%, 45%, and 15%, respectively, our results match the results obtained by Najafi Olya et al . [ 22 ] Furthermore, all isolates were sensitive to rifampin, an inhibitor of RNA synthesis by 100%. Moreover, they were resistant by 20% to ciprofloxacin and levofloxacin.…”

Molecular characterisation of Staphylococcus aureus in school-age children in Guangzhou: associations among agr types, virulence genes, sequence types, and antibiotic resistant phenotypes

“…Panton–Valentine leukocidin S/F (lukS/F-PV, composed of leukocidin S and leukocidin F subunits) is a virulence factor that disrupts the cell membranes of polymorphonuclear neutrophils. lukS/F-PV- S.aureus is involved in invasive infection, such as necrotizing pneumonia, and can be utilized as an epidemiological marker for invasive diseases [ 19 ]. The surface protein SasX, discovered in ST239 in the UK, contributes to MRSA outbreaks by enhancing nasal colonisation, bacterial aggregation, lung diseases, and immune evasion mechanisms [ 20 , 21 ].…”