The number of infections caused by antibiotic resistant bacteria is rising worldwide. Fish from multisource pollution waters can harbour multidrug-resistant bacteria that can be disseminated to humans through eating or contact of contaminated fish. A cross-sectional study was carried out to (i) isolate and phenotypically identify bacteria from 36 fish samples from informal market in Mufakose, Harare, and (ii) determine the antibiotic sensitivity pattern of the isolated bacteria against ten available antibiotics (ampicillin 10 μg, gentamycin 30 μg, penicillin G 10 μg, erythromycin 15 μg, tetracycline 30 μg, kanamycin 30 μg, neomycin 10 μg, cloxacillin 5 μg, lincomycin 15 μg, and sulfamethoxazole 25 μg) using the Kirby–Bauer disk agar diffusion method. Eight bacterial genera were isolated and identified, and they wereEscherichia,Aeromonas,Staphylococcus,Pseudomonas,Citrobacter,Klebsiella,Enterobacter, andProteus. Among the isolates,Escherichia coliwas isolated most frequently (44%) followed byStaphylococcus aureus(19%),Enterobacter aerogenes(7%),Aeromonasspp. (5%),Proteus mirabilis(5%),Citrobacter(5%), and coagulase-negativeStaphylococci(5%) and the least frequent wereKlebsiella(3%) andPseudomonas(3%). All isolates were susceptible to gentamycin. Varying antibiotic resistance rates were observed to lincomycin (100%), ampicillin (81%), penicillin (67%), erythromycin (65%), tetracycline (63%), neomycin (61%), cloxacillin (43%), kanamycin (24%), and sulphamethoxazole (13%). All the isolates were multidrug-resistant (resistant to at 3 or more drugs tested) exceptProteus mirabilis.Proteus mirabilishas multiple antibiotic resistance (MAR) index of 0.2, and the other isolated bacteria had MAR indexes greater than 0.2 ranging from 0.3 to 0.7. Those MAR indexes above 0.2 showed that the bacteria isolates are from a high risk source where antibiotics were frequently used, possibly from sewage effluents. Isolation of enteric bacteria such asEscherichia coliis an indication of faecal contamination, and this poses a high risk to animal and human health. These significant findings call for effective risk assessment models and management plans that protect human, animal, and environmental health.

This paper applies a semi-quantitative approach to review the diversity, environmental controls, detection methods, human health risks, and mitigation of cyanotoxins in drinking water systems (DWSs). It discusses the environmental factors controlling the occurrence of cyanotoxins, presents the merits and limitations of emerging methods of their detection (qPCR, liquid chromatography–mass spectrometry, and electrochemical biosensors), and outlines the human exposure pathways and health outcomes with identification of high-risk groups and settings. High-risk groups include (1) communities relying on untreated drinking water from unsafe, polluted water sources and (2) low-income countries where cyanotoxins are not routinely monitored in DWSs. The fate and behavior processes are discussed, including removing cyanotoxins in DWSs based on conventional and advanced treatment processes. The available methods for cyanotoxin removal presented in this paper include (1) polymer-based adsorbents, (2) coagulation/flocculation, (3) advanced oxidation processes, (4) ultra- and nanofiltration, and (5) multi-soil layer systems. Future research should address (1) detection and fate in storage and conveyance facilities and at the point of consumption, (2) degradation pathways and toxicity of by-products or metabolites, (3) interactive health effects of cyanotoxins with legacy and emerging contaminants, (4) removal by low-cost treatment techniques (e.g., solar disinfection, boiling, bio-sand filtration, and chlorination), (5) quantitative health risk profiling of high-risk groups, and (6) epidemiological studies to link the prevalence of human health outcomes (e.g., cancer) to cyanotoxins in DWSs.

Salmonella enterica is a significant zoonotic pathogen, posing a serious public health threat through its presence in the food supply chain, particularly in poultry production facilities. This study aimed to investigate the genetic diversity, antimicrobial resistance (AMR) profiles and phylogenetic relationships of S. enterica serovars isolated from various stages of the broiler supply chain in Harare, Zimbabwe. Whole-genome sequencing was employed to analyse 28 Salmonella isolates from broiler farms, slaughter facilities and retail markets. The overall prevalence of Salmonella was 5.1% out of 552 samples tested. Contamination rates were higher at slaughter facilities, where 11% of 100 samples tested positive and at retail markets, where 20% of 20 samples were contaminated. In contrast, farms had a significantly lower prevalence, with only 3.0% of 432 samples showing Salmonella presence. Eight serovars were identified, with S. enterica subsp. enterica serovar Typhimurium being the most prevalent at 27.6%. Notably, 34.5% of the isolates harboured resistance genes, including fosA3 , fosA7.2 and qnrB19 , and exhibited mutations in the gyrA and parC regions. An extended-spectrum beta-lactamase-producing S. enterica subsp. enterica serovar Kentucky ST198 strain was isolated from retail chicken cuts. All isolates carried virulence genes such as iroC , iroB and sinH , with sodC1 present in 47.4% of the isolates. Approximately 31% of the isolates co-harboured antimicrobial, stress tolerance and virulence genes. Genomic analysis identified distinct sequence types while also revealing identical core SNPs in genomes across various stages of the supply chain. This study highlights the transmission of Salmonella and AMR in the broiler supply chain, emphasizing the urgent need for improved surveillance and intervention strategies to reduce public health risks from contaminated poultry products.

There is a direct association between the concentration of aflatoxin M1 (AFM1) in milk and of aflatoxin B1 (AFB1) in feed for dairy cattle leading to AFM1 to be found in the milk of animals that are fed on AFB1 contaminated feed. The aim of this study was to determine the occurrence of Aspergillusflavus contamination in dairy cattle feed and quantify the amount of AFM1 in raw cow's milk.