Antimicrobial resistance activity and molecular characterization of methicillin-resistant staphylococci isolates in Tripoli Central Hospital, Libya

Background: Nosocomial infections caused by methicillin-resistant Staphylococci could lead to increased morbidity and mortality, but little is known about the prevalence of infections with these organisms in healthcare facilities and in the community in Tripoli. This study investigated the in vitro susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase negative staphylococci (MRCNS) to antimicrobial agents, and determined the molecular characteristics of MRSA.Methods: This is a retrospective observational study aiming at determining the prevalence and antibiotic resistance pattern of (MRSA) and (MRCNS) isolated from non-duplicated clinical specimens in Tripoli Central Hospital (TCH) between June 2013 and June 2014. Isolates were identified using standard laboratory procedures. Antimicrobial susceptibility tests were carried out by disk diffusion method and automated systems. DNA of the MRSA isolates was used for PCR to determine the molecular analysis.Results: 218 isolates of Staphylococci were obtained, 71.6% were coagulase positive staphylococci (CPS) and 28.4% were coagulase negative staphylococci (CNS). 39.7% of CPS were MRSA, while 75.8% of CNS were MRCNS. The rates of hospital-acquired MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA) among MRSA isolates were 61.3% and 38.7% respectively. A similar trend was detected among MRCNS isolates, where 74.5% were HA-MRCNS and 25.5% were CA-MRCNS. All the MRSA and MRCNS isolates were susceptible (100%) to vancomycin, tigecycline, linezolid, quinupristin/dalfopristin, daptomycin and moxifloxacin. Generally, hospital-acquired strains showed higher resistance rates than community-acquired ones to the most commonly tested non-beta-lactam antibiotics. 35.5% of all staphylococcal isolates exhibited mecA+ gene and 12.9% expressed mecC+. Meanwhile, 38.7% of MRSA isolates harbored both mecA and mecC. However, 12.9% of MSSA isolates were negative for both mecA and mecC. The mecA gene was detectable in 59.1% and 40.9 % of HA-MRSA and CA-MRSA isolates respectively.Conclusion: Hospital-acquired MRSA and MRCNS isolates had higher resistance rates to non-beta lactam antimicrobial drugs than the respective community-acquired isolates. This was shown by early detection of mecC gene among MRSA isolates

Isolement et caracterisation de Burkholderia cepacia lors d'infections hospitalieres

"Le developpement des techniques de reanimation et d'explorations fonctionnelles a entraine une ""explosion des infections nosocomiales"". Cette etude porte sur les souches de Burkholderia cepacia isolees en 1996 dans un hopital pediatrique du CHU de Dakar; suite a l'installation d'aspirateurs tracheo-bronchiques servant au desencombrement des enfants. Les 44 souches de B.cepacia etudiees proviennent de 42 hemocultures pratiquees chez 29 garcons et 13 filles ages de 5 jours a 7 ans et de 2 aspirateurs. Les aspirateurs constituent la source de contamination. Toutes les souches produisent un pigment jaune-orange. Un seul biotype a ete identifie. Le profil de sensibilite aux antibiotiques est presque univoque pour les 44 souches testees. La transmission de B. cepacia resulte de l'installation d'appareil de reanimation medicale dont l'entretien pose probleme. Les infections nosocomiales constatees sont jusqu'ici des bacteriemies simples. L'identification phenotypique et genotypique des souches a montre la circulation d'un seul clone. Le renforcement des mesures d'hygiene est la meilleure solution a ces infections nosocomiales."