Staphylococcus aureus Nasal Carriage Among Patients and Health Care Workers in Sa ˜o Tome ´ and Prı ´ncipe Teresa Conceic ¸a ˜ o, 1 Isabel Santos Silva, 2 Hermı ´nia de Lencastre, 1,3 and Marta Aires-de-Sousa 2 Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen worldwide. However, data on MRSA prevalence in the African continent are scarce and nonexistent for Sa ˜ o Tome ´ and Prı ´ncipe. In November 2010 and April 2012, a total of 332 individuals (258 patients and 74 health care workers [HCW]) from Hospital Dr. Ayres Menezes in Sa ˜ o Tome ´ and Prı ´ncipe, were screened for S. aureus and MRSA carriage. Fifty-two persons (15.7%) were S. aureus nasal carriers out of which 14 (26.9%) were colonized with MRSA. MRSA isolates belonged to three clonal complexes: CC8 (PFGE type B-ST8-t064/t451-IVg/V), CC88 (PFGE E-ST88-t186/t786- IVa), and CC5 (PFGE K-ST5-t105-IVa/PFGE K-ST105-t002-II). A higher genetic diversity was found among methicillin-susceptible S. aureus (MSSA) isolates where 58.5% (n = 24) belonged to four major lineages: PFGE type A-ST15-t084; PFGE C-ST508-t861 or related; PFGE D-ST152-t355 or related; and PFGE G-ST121-t159/t2304. Despite the common nonmultiresistant profile, 98% of the isolates harbored two or more virulence factors. Panton-Valentine leukocidine was detected in 36% of the isolates, all MSSA. S. aureus cross-transmission be- tween HCW and patients in the pediatric and medicine wards and the detection of identical MRSA strains among patients in two different wards evidenced the need of implementation of additional infection control measures in this hospital. Introduction M ethicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen and a serious public health problem worldwide. 16,19 Although efforts to prevent MRSA transmission and infection in the most developed countries receive major research funding, the extent of the MRSA problem remains largely unknown in resource-poor regions. Moreover, surveillance systems to guide interven- tions require expertise and resources, which are very limited in developing countries, where social and health care system deficiencies such as overcrowding and understaffing result in a lack of infection control practices. 8 For an integrated worldwide control of MRSA, studies to appraise the preva- lence and profile of S. aureus disease in developing nations are mandatory. MRSA surveillance data from African countries are scarce, refer to individual hospitals and the different study de- signs and selection of clinical specimens may constrain the comparison of values that are very variable. In West-African countries, MRSA prevalence ranges from 3.7% in carriage and 11% in clinical isolates from Gabon 50 to 15% in infection isolates from five sub-Saharan African towns, 10 16% in Nigeria 54 and 33.6% in Ghana. 38 Higher variability was also reported in East-South Africa: 6.3% in infection and 14.8% in carriage in Madagascar island, 44,45 23% in colonization among Ethiopian children and prisoners, 27 27% in clinical isolates in South Africa, 53 37.5% in surgical site infections and 52% in carriage among health care workers (HCW) and patients in surgical units of Mulago hospital, Uganda, 26,52 and 84.1% in patients with skin and soft tissue infections in Kenya. 31 Sporadic MRSA isolates have been reported in Mali 48 and Tanzania. 57 Information from Portuguese-speaking African countries (PALOP) are almost inexistent and limited to a study that reported an MRSA prevalence of 8% in a single hospital in Mozambique between 2001 and 2006 32 and a study dated from 1997 in Cape Verde islands. 1 Although no MRSA were isolated among nasal swabs from patients and HCW in Cape Verde, an unusually high prevalence (35%) of the highly potent Panton-Valentine leukocidine (PVL) was found among methicillin-susceptible S. aureus (MSSA) iso- lates, sharing the same genetic background as MRSA pan- demic clones. 3 The close relationships between Portugal and PALOP nations may influence the MRSA clonal types circulating in this country. Portugal has been reporting the highest MRSA 1 Laborato ´ rio de Gene ´tica Molecular, Instituto de Tecnologia Quı ´mica e Biolo ´ gica (ITQB), Universidade Nova de Lisboa (UNL), Oeiras, Portugal. 2 Escola Superior de Sau ´ de da Cruz Vermelha Portuguesa (ESSCVP), Lisboa, Portugal. 3 Laboratory of Microbiology, The Rockefeller University, New York, New York. MICROBIAL DRUG RESISTANCE Volume 20, Number 1, 2014 ª Mary Ann Liebert, Inc. DOI: 10.1089/mdr.2013.0136 57