Prevalence and clonality of methicillin-resistant Staphylococcus aureus (MRSA) in the Atlantic Azores islands: predominance of SCCmec types IV, V and VI

• Published in: European journal of clinical microbiology & infectious diseases 2010-05, Vol.29 (5), p.543-550
• Main Authors: Conceição, T, Tavares, A, Miragaia, M, Hyde, K, Aires-de-Sousa, M, de Lencastre, H
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotics; Antimicrobial agents; Archipelagoes; Azores - epidemiology; Bacterial diseases; Bacterial Proteins - genetics; Bacterial Toxins - genetics; Bacterial Typing Techniques - methods; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cloning; Electrophoresis, Gel, Pulsed-Field; Epidemiology; Exotoxins - genetics; Gene Transfer, Horizontal; Human bacterial diseases; Humans; Infectious diseases; Internal Medicine; Islands; Leukocidins - genetics; Medical Microbiology; Medical sciences; Methicillin Resistance - genetics; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Microbial Sensitivity Tests; Molecular Diagnostic Techniques - methods; Pediatrics; Population structure; Prevalence; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcal infections, streptococcal infections, pneumococcal infections; Staphylococcus aureus; Staphylococcus infections
• ISSN: 0934-9723; 1435-4373
• DOI: 10.1007/s10096-010-0892-4

In order to obtain insights into the methicillin-resistant Staphylococcus aureus (MRSA) population structure in the Azores archipelago, 106 MRSA isolates were collected from patients attending an Azorean central hospital between January 2007 and February 2008. Antimicrobial resistance was determined for all isolates. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE), spa typing, multilocus sequence typing (MLST), staphylococcal chromosome cassette mec (SCCmec) typing and the presence of Panton-Valentine leukocidin (PVL). The majority of the isolates (87%, n = 92) belonged to the EMRSA-15 clone (ST22, SCCmec-IVh), followed by the Pediatric clone (ST5-VI/IVc) (11%, n = 12). The Berlin clone (ST45-IVa) and a new clone (spa type t1839, ST1339 and SCCmec V variant) were represented by single isolates. All of the isolates carried SCCmec types IV, V or VI and a non-multiresistant antibiotic profile, resembling the currently emerging community MRSA. Moreover, PVL was described for the first time to be associated with the Pediatric clone carrying SCCmec type VI. We provided the first description of the population structure of MRSA in the Azores islands, which seems to be shaped by genetic events occurring locally, as well as by the regular population exchange between the islands, continental Portugal, the United Kingdom and the United States.