title: MRSA clonal complex 22 strains harboring toxic shock syndrome toxin (TSST-1) are endemic in the primary hospital in Gaza, Palestine.
abstract: BACKGROUND
  Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in both community and healthcare-related settings worldwide. Current knowledge regarding the epidemiology of S. aureus and MRSA in Gaza is based on a single community-based carriage study. Here we describe a cross-sectional analysis of 215 clinical isolates collected from Al-Shifa Hospital in Gaza during 2008 and 2012.
  
  
  METHODS
  All isolates were characterized by spa typing, SCCmec typing, and detection of genes encoding Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin (TSST-1). Representative genotypes were also subjected to multilocus sequence typing (MLST). Antibiotic susceptibility testing was performed using VITEK2 and MicroScan.
  
  
  RESULTS
  MRSA represented 56.3% of all S. aureus strains, and increased in frequency from 2008 (54.8%) to 2012 (58.4%). Aside from beta-lactams, resistance was observed to tetracycline, erythromycin, clindamycin, gentamicin, and fluoroquinolones. Molecular typing identified 35 spa types representing 17 MLST clonal complexes (CC), with spa 998 (Ridom t223, CC22) and spa 70 (Ridom t044, CC80) being the most prevalent. SCCmec types I, III, IV, V and VI were identified among MRSA isolates, while type II was not detected. PVL genes (lukF/S-PV) were detected in 40.0% of all isolates, while the TSST-1 gene (tst) was detected in 27.4% of all isolates, with surprisingly high frequency within CC22 (70.4%). Both PVL and TSST-1 genes were found in several isolates from 2012.
  
  
  CONCLUSIONS
  Molecular typing of clinical isolates from Gaza hospitals revealed unusually high prevalence of TSST-1 genes among CC22 MRSA, which is noteworthy given a recent community study describing widespread carriage of a CC22 MRSA clone known as the 'Gaza strain'. While the latter did not address TSST-1, tst-positive spa 998 (Ridom t223) has been detected in several neighboring countries, and described as endemic in an Italian NICU, suggesting international spread of a 'Middle Eastern variant' of pandemic CC22 strain EMRSA-15.
authors.affiliation: Department of Laboratory Medicine, Al Azhar University-Gaza, Gaza Strip, Palestine; Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America.
authors.forename: Nahed
authors.initials: N
authors.lastname: Al Laham
authors.affiliation: Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America.
authors.forename: José R
authors.initials: JR
authors.lastname: Mediavilla
authors.affiliation: Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: The Central Laboratories, Ministry of Health, Gaza Strip, Palestine.
authors.forename: Nahed
authors.initials: N
authors.lastname: Abdelateef
authors.affiliation: The Central Laboratories, Ministry of Health, Gaza Strip, Palestine.
authors.forename: Farid Abu
authors.initials: FA
authors.lastname: Elamreen
authors.affiliation: Department of Pathology and Laboratory Medicine, North Shore-LIJ Health System, Lake Success, New York, United States of America; Hofstra North Shore-LIJ School of Medicine, Hempstead, New York, United States of America.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Ginocchio
authors.affiliation: Institute of Medical Microbiology, University Hospital of Brussels, Brussels, Belgium.
authors.forename: Denis
authors.initials: D
authors.lastname: Pierard
authors.affiliation: Institute of Medical Microbiology, University Hospital of Muenster, Muenster, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Becker
authors.affiliation: Public Health Research Institute, Rutgers University, Newark, New Jersey, United States of America.
authors.forename: Barry N
authors.initials: BN
authors.lastname: Kreiswirth
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics*; D004768:Enterotoxins / Q000235:genetics*; D005098:Exotoxins / Q000235:genetics; D006761:Hospitals; D007956:Leukocidins / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D008877:Middle East; D018089:Superantigens / Q000235:genetics*
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D018089:Superantigens; C030107:enterotoxin F, Staphylococcal