Characteristics of Staphylococcus aureus Isolated from Patients in Busia County Referral Hospital, Kenya

Abstract

Staphylococcus aureus is an important pathogen associated with hospital, community, and livestock-acquired infections, with the ability to develop resistance to antibiotics. Nasal carriage by hospital inpatients is a risk for opportunistic infections. Antibiotic susceptibility patterns, virulence genes and genetic population structure of S. aureus nasal isolates, from inpatients at Busia County Referral Hospital (BCRH) were analyzed. A total of 263 inpatients were randomly sampled, from May to July 2015. The majority of inpatients (85.9%) were treated empirically with antimicrobials, including ceftriaxone (65.8%) and metronidazole (49.8%). Thirty S. aureus isolates were cultured from 29 inpatients with a prevalence of 11% (10.3% methicillin-susceptible S. aureus (MSSA), 0.8% methicillin resistant S. aureus (MRSA)). Phenotypic and genotypic resistance was highest to penicillin-G (96.8%), trimethoprim (73.3%), and tetracycline (13.3%) with 20% of isolates classified as multidrug resistant. Virulence genes, Panton-Valentine leukocidin (pvl), toxic shock syndrome toxin-1 (tsst-1), and sasX gene were detected in 16.7%, 23.3% and 3.3% of isolates. Phylogenetic analysis showed 4 predominant clonal complexes CC152, CC8, CC80, and CC508. This study has identified that inpatients of BCRH were carriers of S. aureus harbouring virulence genes and resistance to a range of antibiotics. This may indicate a public health risk to other patients and the community.

Displacement of Hospital-Acquired, Methicillin-Resistant Staphylococcus aureus Clones by Heterogeneous Community Strains in Kenya over a 13-Year Period

“…For insights into temporal changes in strain diversity, we compiled MRSA strain type data from this study (n = 86) and from previous studies by Aiken et al (n = 6) [ 15 ], Omuse et al (n = 24) [ 17 ], Kyany’a et al (n = 8) [ 16 ], Nyasinga et al (n = 6) [ 33 ], Njenga et al (n = 4) [ 34 ], and Obanda et al (n = 2) [ 35 ]. The combined set constituted 136 strains that were split into two periods covering the years 2010–2017 (n = 77) and 2018–2023 (n = 59).…”

“…The cooccurrence of tetK and tetM was infrequent in our study (n = 5). dfrG is dominant among Kenyan strains [ 35 ]; but, in the UK, dfrA is common [ 43 ]. The global distribution of erm genes is variable, with isolates from certain regions showing higher frequencies of ermA (South America), ermB (China), and ermC (Europe and middle East) [ 44 ].…”