Nasal carriage of sequence type 22 MRSA and livestock-associated ST398 clones in Tangier, Morocco

Abstract

Introduction: This study aimed to provide data of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage as well as to determine the genetic lineages of this circulating MRSA in the Tangier community.

Methodology:  Between 2012 and 2013 two subpopulations consisting of randomly chosen healthy volunteers and outpatients in 11 healthcare facilities were screened. The antibiotic resistance phenotype was determined by disk diffusion. Toxin Panton-Valentin Leukocidin (PVL), toxic shock syndrome toxin-1 gene (tst), and mecA were detected by polymerase chain reaction (PCR). Nasal swabs were obtained from persons with no identified risk factors for MRSA acquisition. MRSA molecular typing was performed by pulsed-field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec, and Staphylococcus protein A (spa) typing.

Results: A total of400 subjects (33.3%) were nasally colonized with S. aureus, and 17 (1.4%) were nasal carriers of MRSA. The analysis did not identify age, gender, and the two subpopulations as predictors for MRSA colonization. MRSA were more likely to harbor the tst gene (p < 0.05). This work highlighted a low prevalence of nasal MRSA carriage, with 52.94% belonging to sequence type (ST) ST22. The remaining isolates were distributed as singletons (ST8, ST1, and ST398), whereas approximately one-third of MRSA was not identified, including three novel spa-types (t13247, t13248, and t13249).

Conclusions: Although we highlighted the current clones present in the Tangier community, they are limited in space and time. Therefore, further studies would be required to obtain a comprehensive picture of the dissemination of MRSA in the community, hospital, and livestock.