Molecular Characteristics of Staphylococcus aureus from Military Hospital in Abidjan, Côte d’Ivoire

A broad variety of infections, ranging from minor infections of the skin to post-operative wound infections can be caused by Staphylococcus aureus (S. aureus). The adaptive power of S. aureus to antibiotics leaded to the emergence of methicillinresistant S. aureus (MRSA). MRSA strains is characterized by its potential to express many virulence factors, frequently the Panton-Valentine Leukocidin (PVL). Thus MRSA is one of the important pathogens implicated in hospital acquired infection. The main objectives of this study was to find the prevalence of MRSA, the frequency of the PVL and nasal carriage rate in healthy hospital staff. A total of 47 S.aureus strains were isolated, 31 from clinical specimens and 16 from anterior nares swabs from healthy hospital staff. All isolates were tested for the genes of MecA (mecA) and PVL (lukS )using a multiplex PCR (nested PCR). The genes mecA and luks were confirmed respectively in six (19.3%) and twentyfour (77.4%) of clinical isolates. Of the 150 nasal swabs sticks from 30 health-care workers were collected and 16 cultures were positive for S. aureus. The gene mecA was detected in two isolates giving a MRSA nasal carriage level of 1.3%. The luks gene in nasal strain occurred in one case. The results obtained emphasize the continuous monitoring of meticillin susceptibility pattern of S.aureus isolates and the need for high standards of infection control in primary care to prevent MRSA transmission in either direction between healthy hospital staff and patients. Key-words Staphylococcus aureus, méticilline, leucotoxine of Panton-Valentine, pus. INTRODUCTION Staphylococcus aureus (S. aureus) is a leading cause of diseases such as skin and soft tissue infections, pneumonia, bloodstream infections, osteomyelitis and endocarditis, as well as toxin-mediated syndromes like toxic shock and food poisoning [1]. This organism is one of the important pathogens in hospital acquired infection. It has developed resistance to a wide range of antimicrobial drugs, which complicates the treatment of infections. In particular, methicillin-resistant S. aureus (MRSA) has become a notorious etiologic agent for a wide variety of infections and it is one of the most important nosocomial pathogens worldwide [2]. Methicillin-susceptible S. aureus (MSSA) become MRSA through the acquisition and insertion into their genomes of a large DNA fragment known as staphylococcal chromosome cassette mec (SCCmec), which contains the methicillin resistance determinant, mecA [3]. S. aureus is characterized by its potential to express many virulence factors. The Panton-Valentine leucotoxine PVL is a major virulence factor associated with necrotic lesions of the skin and subcutaneous tissues (e.g., furuncles) and also with community-acquired severe necrotic pneumonia [4]. There exists a relationship between antibiotic resistance genes and some virulence genes in the emergence of strains of MRSA from hospital or even community acquired infection. Frequently, MRSA strains carry the gene for PantonValentine Leukocidin (PVL) [5]. Some risk factors are implicated in the transmission of MRSA in hospitals such as the antibiotics selection pressure, use of invasive procedures and ecological niches. In humans, colonization of S.aureus is found in the anterior nares. Nasal carriage of these organisms in hospital staff provides a Original Article Bulletin of Environment, Pharmacology and Life Sciences Online ISSN 2277 – 1808 Bull. Environ. Pharmacol. Life Sci.; Volume 1 [7] June 2012: 54 58 © All Rights Reserved Academy for Environment and Life Sciences, India Website: www.bepls. com