Antibiotic resistance and molecular epidemiology of Staphylococcus aureus in Nigeria

Abstract

BackgroundStaphylococcus aureus is an important pathogen causing a wide range of infections in the hospital and community setting. In order to have adequate information for treatment of S. aureus infections, it is crucial to understand the trends in the antibiotic-resistance patterns. In addition, the occurrence and changes in types of S. aureus, clonal identities, and their geographic spread is essential for the establishment of adequate infection control programmes. In this study, 68 S. aureus isolates obtained from clinical and non-clinical sources in Nigeria between January and April 2009 were characterized using phenotypic and molecular methods.ResultsAll the S. aureus isolates were susceptible to teicoplanin, vancomycin, phosphomycin, fusidic acid, rifampicin, daptomycin, mupirocin, linezolid and tigecycline. Sixteen percent of the isolates were resistant to oxacillin, while 55% and 72% of isolates were resistant to tetracycline and trimethoprim/sulphamethoxazole (cotrimoxazole), respectively (Table 1). There was excellent correlation between the broth microdilution assay and detection of antibiotic resistance genes by the multiplex PCR, in the determination of S. aureus resistance to erythromycin, gentamicin, methicillin and tetracycline. A total of 28 spa types were identified in the study, and the predominant spa type among the methicillin-susceptible S. aureus (MSSA) isolates was t084 (13 isolates). The t037-ST241-SCCmecIII type was the only clone identified in Maiduguri (North-East Nigeria) while in South-West Nigeria, diversity among the MRSA isolates (t451-ST8-SCCmecV; t008-ST94-SCCmecIV; t002-ST5-SCCmecV; t064-ST8-SCCmecV) was observed. The toxin genes seh and etd were detected in isolates affiliated with clonal complexes CC1, CC80 and sequence type ST25, respectively. The proportion of PVL-positive isolates among MSSA was high (40%). Most of the PVL-positive MSSA isolates were obtained from wound infections and associated with clonal complexes CC1, CC30, CC121 and with sequence type ST152.Table 1Antibiotic resistance profile of S. aureus (MSSA and MRSA) from NigeriaNumber (%) of resistant isolates among:AntibioticMSSA(n = 57)MRSA(n = 11)Total(n = 68)Penicillin49 (86)11 (100)60 (88.2)Oxacillin0 (0)11 (100)11 (16.2)Teicoplanin0 (0)0 (0)0 (0)Vancomycin0 (0)0 (0)0 (0)Gentamicin1 (1.8)9 (81.8)10 (14.7)Tetracycline27 (47.4)11 (100)38 (55.9)Ciprofloxacin12 (21.1)8 (72.7)20 (29.4)Moxifloxacin0 (0)7 (63.6)7 (10.3)Trimethoprim/sulfamethoxazole39 (68.4)10 (90.9)49 (72.1)Phosphomycin0 (0)0 (0)0 (0)Fusidic acid0 (0)0 (0)0 (0)Erythromycin2 (3.5)6 (54.5)8 (11.8)Clindamycin0 (0)6 (54.5)6 (8.8)Rifampicin0 (0)0 (0)0 (0)Daptomycin0 (0)0 (0)0 (0)Mupirocin0 (0)0 (0)0 (0)Linezolid0 (0)0 (0)0 (0)Tigecycline0 (0)0 (0)0 (0)ConclusionsThe use of phenotypic and molecular methods provided useful information on antibiotic resistance and molecular diversity of S. aureus in Nigeria. The high proportion of PVL-positive MSSA isolates affiliated to various clonal complexes and detected in all the health institutions is a major conc...

<i>Staphylococcus aureus</i> Prevalence and Antibiotic Susceptibility Profile in Anyigba, North-Central Nigeria

“…In this present study, Staphylococcus aureus isolates were resistant to tetracycline and cotrimoxazole. This compares favourably with reports published by some researchers (Shittu et al, 2011). Egah et al (1999) in their work on antimicrobial susceptibility pattern of Staphylococcus aureus in Jos, documented Staphylococcus aureus as resistant to tetracycline.…”

“…Tetracycline and cotrimoxazole are listed in many developing countries as antimicrobial agents that have been rendered ineffective or with serious concerns regarding bacterial resistance (Okeke, 2003). In Nigeria, they are orally administered and available from various sources where they are sold with or without prescription (Shittu et al, 2011). Staphylococcus aureus susceptibility to Gentamicin and Ofloxacin were 100% and 81.8% respectively.…”

Nasal Carriage of Staphylococcus Aureus among Apparently Healthy School Children in Owerri Metropolis, Nigeria

“…[14][15][16][17][18] To the best of our knowledge, no population-based prevalence study has been carried out to determine Nasal carriage of S. aureus amongst school children in Owerri metropolis, Southeast Nigeria. This study was therefore, aimed at determining the nasal carriage of S. aureus amongst school children in various schools in Owerri and their susceptibility to conventional antibiotics used in the study area.…”

Molecular characterization of methicillin-resistantStaphylococcus aureusisolates in three different Arab world countries

“…Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen associated with signifi cant morbidity, mortality, and hospitalization costs [1][2][3][4][5][6][7]. Currently, sequence-based methods and protein A-encoding gene (spa) typing offer excellent intra-and inter-laboratory reproducibility and the opportunity to compare results internationally [8].…”