Antibiotics resistance patterns of Panton-Valentine leukocidin-positive methicillin-resistant staphylococci isolated from clinical samples in Abidjan, Cte dIvoire

Abstract

Methicillin-resistant staphylococci have emerged as significant pathogens which cause various infections and its multidrug resistance is a major concern. This study aimed to determine the prevalence of Panton-Valentine leukocidin (PVL) gene and antibiotic resistance patterns of staphylococci isolated from clinical infections in Abidjan. A total of 35 staphylococci strains was obtained from 35 clinical samples (pus, blood, pleural fluid, sputum, wound, and urine), then, characterized by polymerase chain reaction (PCR) to differentiate S. aureus from coagulase-negative staphylococci (CNS) and to detect the presence of PVL genes (LukS). The antimicrobial susceptibility was performed using disk diffusion method and the phenotype of resistance to macrolideslincosamides-streptogramin B (MLSB) was detected. Out of 35 strains, 80% (28/35) were methicillinresistant Staphylococcus aureus (MRSA) and 20% (7/35) were methicillin-resistant CNS (MR-CNS). S. aureus were isolated from 75% of outpatient samples and 84.2% of inpatient samples. However, CNS were isolated from 25% of outpatient samples and 15.8% of inpatient samples. LukS were detected in 68.6% of strains (20 MRSA and 4 MR-CNS) and both inpatients and outpatients. The highest resistance rates were observed for penicillin (100%), cefoxitin (100%), ciprofloxacin (66%), tobramycin (66%), tetracyclin (66%), sulphamethoxazole-trimethoprim (63%), erythromycin (60%), kanamycin (57%) and gentamicin (54%). In addition, S. aureus strains were subdivided into five antibiotics resistance phenotypes: 57.1% belonged to phenotype 1 (Methicillin-resistant and susceptible to Kanamycin-Tobramycin-Gentamicin) followed by 25% of phenotype 4 (Resistant to Methicillin-Kanamycin-Tobramycin-Gentamicin), 7.1% of phenotype 2 (MR with constitutive MLSB), 7.1% of phenotype 5 (MR and resistant to Kanamycin-Tobramycin-Gentamicin with inducible MLSB) and 3.6% of phenotype 3 (MR with inducible MLSB). CNS strains were grouped in three phenotypes (1, 4 and 5). 100% of LukS positive MRSA were multi-drug resistant, with 45% of strains resistant to 6 or more antibiotics. The high level of multi-drug resistance of clinical PVL positive staphylococci with inducible MLSB, suggest increasing the monitoring of these pathogens in Cote d'Ivoire.