Multiple antimicrobial resistance indices of Staphylococcus aureus from the nares of goats and slaughterhouse attendants in Kampala city, Uganda- a cross sectional study.

The emergence of antimicrobial resistance (AMR) is a global menace to both public and animal health sectors with devastating effects in developing countries. Indiscriminate use of antibiotics in human health and livestock management contributes to development and rapid spread of AMR. Staphylococcus aureus is a major opportunistic zoonotic pathogen that colonises the skin and nostrils of human beings and animals and continues to develop antimicrobial resistance against different agents. The study aimed to determine multiple antibiotic resistance indices of S. aureus isolates from healthy domestic goats and slaughterhouse attendants in Kampala, Uganda.Demographic characteristics of consenting slaughterhouse attendants and goat keepers were recorded through a questionnaire. Antibiotics use among slaughterhouse workers and domestic goats and skin infections in the past twelve months were recorded. Nasal swabs were collected from healthy domestic goats at household level (n = 378) and slaughterhouse attendants (n = 131). Isolates were obtained on mannitol salt agar (MSA) upon incubation at 35°C for 24 h. The Kirby-Bauer disc diffusion method was used to determine antimicrobial susceptibility to penicillin, gentamycin, erythromycin, tetracycline, ciprofloxacin, clindamycin, trimethoprim-sulfamethoxazole, linezolid, amoxicillin, ceftriaxone and cefoxitin. In this study, the participating slaughterhouse workers were predominantly male (79%) while does (90%) were the majority of the goats sampled. S. aureus carriage was 32% and 43% among slaughterhouse workers and goats, respectively. Methicillin resistant S. aureus carriage was 12% and 11% among slaughterhouse attendants and goats, respectively. There was a high level of exposure to antibiotics among S. aureus carriers (62%) and goats (41%) in the past one year, including use of critically important antimicrobials in human medicine for livestock disease management. Amoxicillin (17%) and ciprofloxacin (12%) were the most used antibiotics among the S. aureus carriers. Oxytetracycline (33%) and Penicillin-streptomycin combination (21%) were the most used antimicrobials in goat keeping. Close to a quarter of the human participants reported having suffered probable staphylococcal related infections like pustules in the previous months. With the exception of gentamycin and linezolid, all the S. aureus isolates from human nasal swabs were resistant to at least one of the antibiotics used. S. aureus isolates from goats' nasal swabs were resistant to at least one of the antibiotics studied. The multiple antibiotic resistance (MAR) index of 41% of S. aureus isolates from slaughterhouse attendants was greater than 0.2 (mean = 0.2 ± 0.2, range 0.1 to 0.7). The MAR index of 22% of S. aureus isolates from goats was greater than 0.2 (mean = 0.2 ± 0.1, range = 0 to 0.7). The most frequent multidrug resistance (MDR) pattern was FOX, CIP, E, TE, SXT, CRO, and CD among S. aureus isolates from slaughterhouse attendants. The most frequent MDR patterns for the isolates from goats were E, TE, CRO, CD and TE, CRO, CD. Healthy domestic goats and slaughterhouse workers are carriers of multidrug resistant S. aureus strains in Kampala city.