MRSA Clonal Complex 22 Strains Harboring Toxic Shock Syndrome Toxin (TSST-1) Are Endemic in the Primary Hospital in Gaza, Palestine

March MRSA Clonal Complex 22 Strains Harboring Toxic Shock Syndrome Toxin (TSST-1) Are Endemic in the Primary Hospital in Gaza, Palestine Nahed Al Laham 0 1 2 Jos R. Mediavilla 0 1 2 Liang Chen 0 1 2 Nahed Abdelateef 0 1 2 Farid Abu Elamreen 0 1 2 Christine C. Ginocchio 0 1 2 Denis Pierard 0 1 2 Karsten Becker 0 1 2 Barry N. Kreiswirth 0 1 2 0 Funding: The first author (NAL) received support for living expenses from several institutions, including the Fulbright Scholar Program (Department of State, Bureau of Educational and Cultural Affairs, United States), the German Academic Exchange Service (DAAD, Germany), and the Erasmus Mundus External Cooperation Window (EM ECW lot III, Belgium), for support of his work during his visits to 1 Academic Editor: Patrick Butaye, Ross University School of Veterinary Medicine, SAINT KITTS AND NEVIS 2 1 Department of Laboratory Medicine, Al Azhar University-Gaza, Gaza Strip, Palestine, 2 Public Health Research Institute, Rutgers University , Newark , New Jersey, United States of America , 3 The Central Laboratories , Ministry of Health, Gaza Strip, Palestine, 4 Department of Pathology and Laboratory Medicine, North Shore-LIJ Health System, Lake Success, New York, United States of America, 5 Hofstra North Shore- LIJ School of Medicine, Hempstead, New York, United States of America, 6 Institute of Medical Microbiology, University Hospital of Brussels , Brussels , Belgium , 7 Institute of Medical Microbiology, University Hospital of Muenster , Muenster , Germany These authors contributed equally to this work. * 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 AlAll 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. - 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 the Public Health Research Institute, Rutgers University, United States; the University Hospital of Muenster, Germany; and the Free University of Brussels, Belgium, respectively. All funding was for personal living expenses only; the agencies listed did not play any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. (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. Staphylococcus aureus is one of the most prevalent human pathogens isolated from hospitalized patients worldwide, and its importance in community settings continues to increase. S. aureus causes a broad variety of diseases ranging from skin and soft-tissue infections to bacteremia, osteomyelitis, infective endocarditis, and necrotizing pneumonia [13]. In recent decades, MRSA has emerged as the most frequently identified antibiotic-resistant pathogen in many parts of the world, including North Africa and the Middle East [4]. While hospital-acquired MRSA (HA-MRSA) strains remain endemic in most of these regions, in recent years community-acquired (CA-MRSA) strains have emerged as a cause of invasive and life-threatening infections in young, healthy patients with no significant healthcare exposure [2,58]. Within the past few years, livestock-associated MRSA (LA-MRSA) have posed an additional threat [911]. Fortunately, whereas HA-MRSA isolates are generally multi-drug resistant, CA-MRSA and LA-MRSA tend to be resistant primarily to beta-lactam antibiotics and, in the case of LAMRSA CC398, to tetracycline as well. Molecular typing techniques are indispensable for understanding the evolution and epidemiology of S. aureus and MRSA. The most widely used techniques include staphylococcal protein A (spa) typing [12,13], staphylococcal cassette chromosome (SCC) mec typing [14], multilocus sequence typing (MLST) [15], and pulsed-field gel electrophoresis (PFGE) [16]. Other markers of interest include virulence factors such as Panton-Valentine leukocidin (PVL) and TSST-1, the principal cause of staphylococcal toxic shock syndrome [17]. Approximately 20% of S. aureus isolates possess the gene encoding TSST-1 (tst) [18], which is harbored by a family of mobile staphylococcal pathogenicity islands (SaPI) [1921]. The distribution of TSST-1 appears limited to a handful of clonal lineages, and is most frequently associated with methicillin-susceptible S. aureus (MSSA) strains belonging to MLST clonal complex (CC) 30. More recently, a tst-positive strain of CC5 MRSA has been documented in France [22], while several reports have described tst-positive CC22 MRSA strains in Abu Dhabi [23], Jordan [24,25], Kuwait [26], Saudi Arabia [27], India [3], Italy [28,29], the United Kingdom [30], and the United States [31]. Several recent studies have also described tst-positive CC30 [25] and CC80 [24,32] MRSA in Jordan. Molecular epidemiological data about S. aureus and MRSA in the Middle East, including the Palestinian Territories, are generally scarce and insufficient [4,3335], with current knowledge regarding the epidemiology of S. aureus in Gaza based on a single recent communitybased carriage study [36]. The Gaza Strip (geographic coordinates 31250 N, 34 200 E) is a narrow territory (41 km long and 612 km wide) along the eastern Mediterranean coast, with tightly-controlled borders abutting Israel and the Sinai Peninsula of Egypt. It is considered one of the m (...truncated)