Study of susceptibility to antibiotics and molecular characterization of high virulence Staphylococcus aureus strains isolated from a rural hospital in Ethiopia

Abstract

We characterised 80 Staphylococcus aureus strains isolated from human patients with SSTIs at a rural hospital in Ethiopia. Susceptibility to antibiotic of all strains was tested. The MLST method was used to type and a phylogenetic analysis was conducted employing the sequences of 7 housekeeping genes. PCR amplification was used to investigate the presence of the following virulence genes in all strains: hla (α-haemolysin), tstH (toxic shock syndrome toxin), luk PV (Panton-Valentine leukocidin), fnbA (fibronectin binding protein A) and mecA (methicillin resistance). Most of the strains were resistant to penicillin and ampicillin, but only 3 strains were resistant to oxacillin, and 1 of them was a true MRSA. The MLST results showed a high diversity of sequence types (ST), 55% of which were new, and ST152 was the most prevalent. A phylogeny study showed that many of the new STs were phylogenetically related to other previously described STs, but bore little relationship to the only ST from Ethiopia described in the database. Virulence gene detection showed a high prevalence of strains encoding the hla, fnbA and pvl genes (98.77%, 96.3% and 72.84%, respectively), a low prevalence of the tst gene (13.58%) and a markedly low prevalence of MRSA (1.25%). S. aureus strains isolated from patients in a rural area in Ethiopia showed low levels of antibiotic resistance, except to penicillin. Moreover, this study reveals new STs in Eastern Africa that are phylogenetically related to other previously described STs, and confirm the high prevalence of the pvl gene and the low prevalence of MRSA on the continent.

Virulence Factor Genes and Antimicrobial Susceptibility of Staphylococcus aureus Strains Isolated from Blood and Chronic Wounds

“…The luk-F/S-PV gene is detected more often in SSTI isolates than in SAB isolates [ 15 , 26 , 32 , 45 , 46 , 47 , 48 ], which confirms our results. The incidence of luk-F/S-PV gene in this study, however, was not high (3.0%), unlike the results of other researchers, in which it reached about 80% [ 35 , 47 ].…”

Antimicrobial Resistance Rates and Surveillance in Sub-Saharan Africa: Where Are We Now?

“…Moreover, the most prevalent genotypes have been demonstrated to be ST5, ST8, ST15, ST88, ST152, ST241, and ST239. 162 , 169–171 …”

“…Nevertheless, community and healthcare-associated MRSA has been reported in most countries, including Kenya, Uganda, Nigeria, South Africa, Ghana, Mozambique, Ethiopia, and Tanzania, where the MRSA prevalence ranges from 1.25% to 53.4%. [157][158][159][160][161][162][163][164] The most common risk factors associated with MRSA infection are HIV infection, prior antibiotic use, ICU admission, prior or prolonged hospitalization, indwelling catheters, invasive procedures, open wounds and burns, residency at long-term care facilities, mechanical ventilation, renal failure, and MRSA colonization history. 165,166 Laboratory diagnosis is by culture, serology, and molecular assays.…”

Çeşitli Klinik Örneklerden İzole Edilen Metisiline Dirençli ve Duyarlı Staphylococcus aureus Suşlarının Toksin Profillerinin Araştırılması

“…This feature of the agent is due to its genome plasticity of acquiring and incorporating genetic materials from other bacterial species that may have antimicrobial resistance and virulence. Thus, outcome of the infections caused by S. aureus strains are closely related with their resistance and virulence properties (2). S. aureus has the ability to produce several virulence factors such as superantigens (SAgs), hemolysins (HLYs), leukotoxins (LUKs), and exfoliative toxins (ETs).…”

“…Among the exotoxins secreted by S. aureus, staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin-1 (TSST-1) have SAg activity. These toxins are important virulence factors that contribute a variety of pathological conditions, including pneumonia, soft tissue infections, toxic shock syndrome, and infective endocarditis (2,3). Moreover, it has been recently reported that SAgs particularly SEs play a prominent role in the development of asthma of hospitalized patients via induction of IgE (4).…”