Gram-positive pathogens in skin and soft tissue infections: is resistance a challenge in clinical practice?

Abstract

Background: The emergence and spread of drug-resistant pathogens continue to threaten the ability to treat common infections. Thus, the current antimicrobial resistance (AMR) survey seeks to present the antibiotic profile of Gram-positive pathogens in skin and soft tissue infections (SSTIs). The objective was to determine the antibiotic susceptibility profile of Gram-positive pathogens causing SSTIs isolated in patients admitted to two tertiary hospitals in Limpopo, South Africa.
Methods: Five-year laboratory-based antibiotic susceptibility data from 2016 to 2020 was reviewed. Susceptibility determinations were done at the National Health Laboratory Service (NHLS), Microbiology Laboratory, according to Clinical & Laboratory Standards Institute (CLSI) guidelines. Data was obtained retrospectively from the central data warehouse (CDW) in Johannesburg. Susceptibility percentages were calculated and reported as a simple percentage of the total number of same-species microbes against which the antibiotic was tested for susceptibility.
Results: A total of 1 669 Gram-positive isolates were analysed. The proportions of males and females were 50.5% and 49.5% respectively. The predominant pathogen was S. aureus representing 67.3% of the isolates. E. faecalis was the second most isolated pathogen (11.7%), followed by Streptococcus group A (3.0%), E. faecium (2.9%), Viridians group Streptococcus (2.6%), and Streptococcus agalactiae (2.3%). A high level of resistance was noted among Staphylococcus aureus due to the presence of methicillin-resistant Staphylococcus aureus (MRSA) at 11.9% and vancomycin-resistant Staphylococcus aureus (VRSA) at < 1%, and in the Enterococcus species, vancomycin-resistant Enterococcus (VRE) at 4% and linezolid-resistant Enterococcus at 2%.
Conclusion: The current AMR survey reports the presence of highly resistant isolates of S. aureus and Enterococcus species at two tertiary hospitals in Limpopo. The present resistant strains, especially MRSA and VRE mean efforts and resources should be channelled to the development of novel antibiotics, while intense infection prevention and control (IPC) measures continue to be adhered to in healthcare facilities.