title: Molecular characterisation of Panton-Valentine leucocidin-producing methicillin-resistantStaphylococcus aureusclones isolated from the main hospitals in Taif, KSA.
abstract: BACKGROUND
  Panton-Valentine leucocidin (PVL) is a bicomponent pore-forming cytolytic toxin encoded by the lukF-PV and lukS-PV genes. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) may carry the pvl genes which may be related to increased disease severity. This study aimed to characterise the PVL-producing MRSA recovered from different Taif Hospitals, Saudi Arabia.
  
  
  METHODS
  The study included 45 hospital-acquired-MRSA (HA-MRSA) and 26 CA-MRSA strains which were identified from 445 S. aureus strains isolated from different clinical samples. MRSA strains were identified by standard oxacillin salt agar screening procedure and by the detection of the mecA gene by the polymerase chain reaction (PCR). Detection of the S. aureus-specific femA, mecA and pvl genes was performed by multiplex PCR. PCR-restriction fragment length polymorphism (PCR-RFLP) analysis was done for coagulase (coa) gene.
  
  
  RESULTS
  The staphylococcal cassette chromosome mec types of the 45 HA-MRSA strains were Type I (n = 24), Type II (n = 7) and Type III (n = 14) whereas the 26 CA-MRSA strains were Type IV (n = 14), Type V (n = 11) and one isolate was non-typeable. All the HA-MRSA and six CA-MRSA strains were PVL-negative PCR-RFLP analysis of coa gene showed that PVL-positive MRSA (n = 20) isolates showed six different patterns, and five patterns were shared by PVL-positive methicillin-susceptible S. aureus (MSSA). The eighth pattern was the most frequent in both MRSA and MSSA.
  
  
  CONCLUSIONS
  PVL is more frequent among CA-MRSA than MSSA. All the HA-MRSA and 25% of CA-MRSA strains were negative for PVL. The pvl gene was related to the severity of infection but not related to coa gene RFLP pattern.
authors.affiliation: Department of Clinical Laboratories, Faculty of Applied Medical Sciences, Taif University, Taif, Saudi Arabia;Department of Medical Microbiology and Immunology, Faculty of Medicine, Menoufia University, Menofia Governorate, Zagazig, Egypt.
authors.forename: E M
authors.initials: EM
authors.lastname: Eed
authors.affiliation: Department of Clinical Laboratories, Faculty of Applied Medical Sciences, Taif University, Taif, Saudi Arabia;Department of Medical Microbiology and Immunology, Faculty of Medicine, Menoufia University, Menofia Governorate, Zagazig, Egypt.
authors.forename: M M
authors.initials: MM
authors.lastname: Ghonaim
authors.affiliation: Department of Clinical Laboratories, Faculty of Applied Medical Sciences, Taif University, Taif, Saudi Arabia; Department of Medical Biochemistry, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
authors.forename: Y M
authors.initials: YM
authors.lastname: Hussein
authors.affiliation: Department of Clinical Laboratories, Faculty of Applied Medical Sciences, Taif University, Taif, Saudi Arabia; Department of Clinical Pathology, Faculty of Medicine, Menoufia University, Menofia Governorate, Zagazig, Egypt.
authors.forename: S S
authors.initials: SS
authors.lastname: Al-Shehri
authors.affiliation: Department of Clinical Pathology, Faculty of Pharmacy, Taif University, Taif, Saudi Arabia.
authors.forename: A S
authors.initials: AS
authors.lastname: Khalifa
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics*; D001431:Bacteriological Techniques; D003030:Coagulase / Q000235:genetics; D017714:Community-Acquired Infections / Q000382:microbiology; D003428:Cross Infection / Q000382:microbiology; D005098:Exotoxins / Q000235:genetics*; D005838:Genotype; D006761:Hospitals; D006801:Humans; D007956:Leukocidins / Q000235:genetics*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D046915:Penicillin-Binding Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012529:Saudi Arabia; D013203:Staphylococcal Infections / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003030:Coagulase; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D046915:Penicillin-Binding Proteins; D037521:Virulence Factors; C487789:mecA protein, Staphylococcus aureus