Phenotypic and molecular characterization of coagulase negative staphylococci from pigs and humans in Lusaka province, Zambia.

Coagulase-negative staphylococci (CoNS) are normal inhabitants of human and animal skin as well as mucous membranes, yet they have emerged as significant pathogens in healthcare settings, causing serious infections. Initially described as avirulent in 1884, CoNS, particularly Staphylococcus epidermidis, are now recognized for their role in healthcare-associated infections contributing to 30-40% of nosocomial infections. Recent studies have highlighted the public health implications of CoNS as they can transfer antibiotic resistance genes and cause infections such as urinary tract infections, endocarditis and surgical site infections. While CoNS have been primarily studied in hospital environments, data from community settings, particularly in Africa, remain scarce. This gap in knowledge hinders a comprehensive understanding of the epidemiology and challenges associated with CoNS infections in the region. The objective of this study was to characterize CoNS isolated from pigs and humans working with pigs on selected farms in Lusaka Province using phenotypic and molecular techniques including the prevalence and resistance profiles of CoNS in Zambia. This was a cross-sectional study which involved archived CoNS isolates from pigs and humans working with pigs on selected farms in Lusaka Province. Species identification of the CoNS was done using traditional microbiological techniques such as culture and molecular methods like polymerase chain reaction (PCR). Antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method, while data was analyzed using SPSS version 28 (IBM Corp, Armonk, NY, USA). Common species identified were S. captis, S. warneri, S. xylosus, S. sciuri and S. caprae. The isolates were generally susceptible to antibiotics especially gentamycin (97%), chloramphenicol (96.3%) and ciprofloxacin (93.3%). Despite being susceptible, they also expressed a high prevalence of multidrug resistance at 60.7% to beta-lactams, tetracyclines, phenicols, sulfonamides, lincosamides and aminoglycosides. While, Methicillin Resistant-CoNS were prevalent when tested using phenotypic methods, none of the MR-CoNS tested positive for the mecA gene using PCR, suggesting other resistance mechanisms may be at work. These findings are significant to both animal and human health and suggest the importance of increased surveillance, antimicrobial stewardship (AMS) and research into resistance mechanisms of CoNS.

Grantor dc:publisher

The University of Zambia

Year dc:date.issued

2025

Author dc:creator

• Chiyomba, Liswaniso

Language dc:language.iso

en

Repository record dc:identifier.uri

https://dspace.unza.zm/handle/123456789/9172

OAI identifier oai:identifier

oai:dspace.unza.zm:123456789/9172