Staphylococcus aureus is an important opportunistic pathogen of both humans and animals. It can cause several diseases, including mastitis, as well as food poisoning by production of heat-stable enterotoxins in food. The aim of this study was to determine the prevalence of S. aureus and the diversity of strains circulating in the Zambian dairy value chain, which have not been studied in detail before. Three provinces were covered by the study (Lusaka, Southern, and Western) and almost 2000 samples along the dairy value chain, covering both the informal and formal market sectors, were taken at two time points (dry and wet season), with a special focus on raw milk. Nearly 300 presumptive S. aureus isolates were confirmed by MALDI-TOF MS and real-time PCR. Raw milk from traditional and smallholder farms was widely contaminated with S. aureus; prevalence was 33-46% depending on the study province. Raw milk from milk collection centres, informal traders, traditional market sellers, and processors were also frequently contaminated with S. aureus. In addition, S. aureus was detected in several milk bucket swabs and nasal and hand swabs of milkers. From industrially processed (heat-treated) milk and dairy products, no S. aureus was isolated. Methicillin-resistant S. aureus (MRSA) were not detected, but around 10% of the S. aureus isolates carried lukS-PV, a marker gene for the virulence factor Pantone-Valentine leucocidin (PVL), which has been associated with severe diseases in human. Molecular typing identified a total of 44 spa types including 13 novel types: t18396, t18397, t18398, t18399, t18400, t18402, t18416, t20459, t20460, t20461, t20462, t20463, and t20464. Furthermore, 12 novel multi-locus sequence types were identified: ST7012, ST7100, ST7101, ST7177, ST7291, ST7304, ST7305, ST7344, ST7596, ST7597, ST7598, and ST7599, of which ST7012, ST7177, and ST7596 fall into the bovine-associated clonal linage CC97. The spa types t084, t267, t355, and the novel type t20464 were common in all three study provinces. The predominant spa type varied depending on the province. Whole genome sequencing (WGS) and core genome multi-locus sequence typing (cgMLST) indicates transmission of strains along the Zambian dairy chain with possible persistence in the chain over time. cgMLST also revealed a very close relatedness between some isolates from milkers and from raw milk or milk buckets. The high prevalence and wide spa type diversity of S. aureus, as well as possible direct or indirect transmission of (potentially highly virulent) S. aureus to humans along the Zambian dairy value chain, are of public health concern, particularly as milk and milk products are often consumed raw by the Zambian population.

Ticks are important vectors for Rickettsia spp. belonging to the Spotted Fever Group responsible for causing Rickettsiosis worldwide. Rickettsioses pose an underestimated health risk to tourists and local inhabitants. There is evidence of the presence of Rickettsia spp. in Zambia, however there is limited data. A total of 1465 ticks were collected in 20 different locations from dogs and cattle including one cat. Ticks were identified by morphological features or by sequencing of the 16S mitochondrial rRNA gene. Individual ticks were further tested for rickettsiae using a pan-Rickettsia real-time-PCR. Rickettsia species in PCR-positive ticks were identified by sequencing the 23S-5S intergenic spacer region or partial ompA gene, respectively. Seven tick species belonging to three different tick genera were found, namely: Amblyomma variegatum, Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) microplus, Rhipicephalus simus, Rhipicephalus sanguineus, Rhipicephalus zambesiensis and Haemaphysalis elliptica. Out of the 1465 ticks collected, 67 (4.6%) tested positive in the pan-Rickettsia PCR. This study provides detailed data about the presence of Rickettsia species in South Luangwa Valley, Eastern Province, Zambia for the first time. High prevalence of Rickettsia africae in Amblyomma variegatum was found, which indicates the potential risk of infection in the investigated area. Furthermore, to our best knowledge, this is the first time Rickettsia massiliae, a human pathogen causing spotted fever, has been detected in Zambia.

Background/Objectives: Antimicrobial Resistance (AMR) remains a growing public health threat, underscoring the need for robust surveillance of Antimicrobial Consumption (AMC) and Antimicrobial Use (AMU). This study analysed AMC and AMU trends in Zambia’s human and animal health sectors, identifying priority areas for antimicrobial stewardship (AMS) under a One Health framework. Methods: A retrospective study was conducted in February 2025, utilising data from 2018 to 2023. Sources of data included the Zambia Medicines Regulatory Authority (ZAMRA) and the WOAH Animal Antimicrobial Use (ANIMUSE) Global Database platform. AMC was analysed using the WHO Global Antimicrobial Resistance and Use Surveillance System (GLASS) methodology. Antimicrobials were classified using the WHO Anatomical Therapeutic Chemical (ATC) system, and consumption was measured in Defined Daily Doses (DDDs) per 1000 inhabitants per day (DID). Antibiotics were further categorised using the WHO Access, Watch, and Reserve (AwaRe) classification. Data analysis was performed using IBM SPPS version 25.0. Results: In the human health sector, oral antibiotics accounted for 88% of total consumption. Penicillins (33%), cephalosporins (19.2%), and macrolides (12.4%) were the most consumed classes. In 2023, 98,651,882.42 DDDs per 1000 inhabitants/day were recorded, with amoxicillin, ceftriaxone, and sulfamethoxazole/trimethoprim leading as the most consumed antibiotics. According to the consumption of antibiotics by the WHO AwaRe classification, 47% were Access, 40% Watch, and 3% Reserve group antibiotics. In animal health, tetracyclines dominated (63%), followed by sulphonamides (26%) and penicillins (11%). AMU in animal health peaked in 2023. Conclusions: This study found high AMC and AMU, especially Watch-group antibiotics and tetracyclines, highlighting the need for strengthened antimicrobial stewardship, regulatory oversight, and integrated One Health surveillance to mitigate AMR risks in Zambia.

The most common health risk associated with consumption of beef is microbial contamination, therefore the study was aimed to assess the level of bacterial contamination of beef and evaluate the hygienic practices in butcheries in Kasama district. Beef samples were collected from participating butcheries and a structured questionnaire was also administered to the food handlers. Microbiological quality of the beef samples was determined by Aerobic Plate Count (APC), Faecal Coliform Count (FCC) and bacterial isolation such as Salmonella spp and Staphylococcus aureus . The APC results revealed 40.7% of the butcheries sold meat in good bacterial condition (5 Log10 cfu/g), respectively. The FCC revealed that 74.1% of the butcheries sold meat in good bacterial conditions (3 Log10 cfu/g), respectively. Staphylococcus aureus was isolated from 37% of the butcheries, none of the outlets recorded Salmonella spp. Overall, the microbial quality of most (74.1%) of the market ready beef in Kasama district was acceptable for human consumption. Therefore, regular bacteriological monitoring and maintaining hygiene in the sales outlets and distribution chain is mandatory.

Pigs have been shown to be a reservoir for recently emerging livestock-associated Staphylococcus aureus (LA-SA), including methicillin resistant strains in many countries worldwide. However, there is sparse information about LA-SA strains circulating in Zambia. This study investigated the prevalence, phenotypic and genotypic characteristics of S. aureus from pigs and workers at farms and abattoirs handling pigs in Lusaka Province of Zambia. A total of 492 nasal pig swabs, 53 hand and 53 nasal human swabs were collected from farms and abattoirs in selected districts. Standard microbiological methods were used to isolate and determine antimicrobial susceptibility patterns of S. aureus. Polymerase Chain Reaction was used to confirm the species identity and detect antimicrobial resistance and virulence genes of isolates, whereas genetic diversity was evaluated using spa typing. Overall prevalence of S. aureus was 33.1%, 37.8% for pigs and 11.8% for humans. The isolates were resistant to several antibiotics with resistance ranging from 18% to 98% but were all susceptible to vancomycin. Typical LA-SA spa types were detected. The presence of plasmid mediated resistance genes such as tetM (12.8%), other resistance determinants and immune evasion cluster genes among the isolates is of great public health concern. Thus, continuous surveillance of S. aureus using a “One health” approach is warranted to monitor S.aureus infections and spread of antimicrobial resistance.

Background. Carbapenem and third-generation cephalosporin (3GC) resistance among Gram-negative bacteria poses a serious threat to human and animal health. This study aimed to identify and characterize carbapenem- and 3GC-resistant Enterobacterales isolated from poultry in Lusaka Province, Zambia. Methods. Ninety pooled cloacal samples were collected from market-ready broiler chickens in the Chongwe and Chilanga districts of Lusaka Province. The isolates were screened for 3GC and carbapenem resistance using the disc diffusion and broth microdilution methods. PCR and Sanger sequencing were performed for species identification and detection of β-lactamase-encoding ( bla ) genes, including bla _CTX-M , bla _TEM , bla _OXA-1 and bla _SHV . Hierarchical clustering was used to assess phenotypic and genotypic relationships. Results. A total of 83 3GC-resistant Gram-negative isolates were recovered, of which 12% were also carbapenem resistant. Escherichia coli was the most prevalent species, followed by Klebsiella pneumoniae and Enterobacter spp., then Pseudomonas aeruginosa, other Pseudomonas spp., Acinetobacter baumannii , Citrobacter freundii and Aeromonas caviae . Multidrug resistance occurred in 84.3% of the isolates, with the highest resistance to ampicillin, tetracycline and co-trimoxazole. Overall, 80.7% of the isolates harboured at least one of the four tested bla genes, with bla _CTX-M and bla _TEM being the most common. Hierarchical clustering revealed that isolates from both districts shared similar phenotypic and genotypic resistance patterns. Conclusions. The presence of multidrug- and carbapenem-resistant Enterobacterales from poultry highlights the emergence of carbapenem resistance in Zambia’s food production sector. The detection of imipenem-resistant isolates indicates the potential for transmission of resistance genes between animals and humans. These findings underscore the need for prudent antimicrobial use, strengthened stewardship and a One Health surveillance approach to contain the spread of carbapenem resistance genes.