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

PLoS One. 2020 Mar 12;15(3):e0230031. doi: 10.1371/journal.pone.0230031. eCollection 2020.

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.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / classification
  • Bacterial Proteins / genetics
  • Bacterial Toxins / classification
  • Bacterial Toxins / genetics
  • Ceftaroline
  • Cephalosporins / pharmacology
  • Drug Resistance, Bacterial / genetics
  • Ethiopia
  • Exotoxins / classification
  • Exotoxins / genetics
  • Hospitals, Rural
  • Humans
  • Leukocidins / classification
  • Leukocidins / genetics
  • Methicillin-Resistant Staphylococcus aureus / drug effects
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Microbial Sensitivity Tests
  • Multilocus Sequence Typing
  • Penicillins / pharmacology
  • Phylogeny
  • Staphylococcal Infections / diagnosis
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / isolation & purification
  • Staphylococcus aureus / pathogenicity
  • Virulence / genetics*

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Bacterial Toxins
  • Cephalosporins
  • Exotoxins
  • Leukocidins
  • Panton-Valentine leukocidin
  • Penicillins

Grants and funding

The author(s) received no specific funding for this work.