Characterisation of Staphylococcus aureus isolates from bloodstream infections, Democratic Republic of the Congo

Eur J Clin Microbiol Infect Dis. 2017 Jul;36(7):1163-1171. doi: 10.1007/s10096-017-2904-0. Epub 2017 Jan 23.

Abstract

Staphylococcus aureus is known worldwide as an invasive pathogen, but information on S. aureus from bloodstream infections in Central Africa remains scarce. A collection of S. aureus blood culture isolates recovered from hospitals in four provinces in the Democratic Republic of the Congo (2009-2013) was assessed. A total of 27/108 isolates were methicillin-resistant S. aureus (MRSA), of which >70% were co-resistant to aminoglycosides, tetracyclines, macrolides and lincosamides. For MRSA and methicillin-susceptible S. aureus (MSSA) isolates, resistance to chloramphenicol and trimethoprim-sulphamethoxazole (TMP-SMX) was <10%. However, 66.7% (72/108) of all isolates harboured the trimethoprim resistance gene dfrG. More than three-quarters (84/108, 77.8%) of isolates belonged to CC5, CC8, CC121 or CC152. Genetic diversity was higher among MSSA (31 spa types) compared to MRSA (four spa types). Most MRSA (23/27, 85.2%) belonged to CC8-spa t1476-SCCmec V and 17/23 (73.9%) MRSA ST8 were oxacillin susceptible but cefoxitin resistant. Among MRSA and MSSA combined, 49.1% (53/108) and 19.4% (21/108) contained the genes encoding for Panton-Valentine leucocidin (lukS-lukF PV, PVL) and toxic shock syndrome toxin-1 (tst, TSST-1), respectively. PVL was mainly detected among MSSA (51/53 isolates harbouring PVL were MSSA, 96.2%) and associated with CC121, CC152, CC1 and CC5. TSST-1 was associated with CC8-spa t1476-SCCmec V. The immune evasion cluster (IEC) genes scn, sak and chp were detected in 81.5% of isolates (88/108, equally represented among MSSA and MRSA). The present study confirms the occurrence of MRSA with high levels of multidrug co-resistance and PVL-positive MSSA among invasive S. aureus isolates in Central Africa.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology*
  • Child
  • Child, Preschool
  • Democratic Republic of the Congo
  • Drug Resistance, Bacterial*
  • Female
  • Genetic Variation*
  • Genotype
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Sepsis / microbiology*
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / classification*
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification
  • Virulence Factors / genetics
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Virulence Factors