The use of untreated livestock manure in urban agriculture sustains soil fertility but risks disseminating antimicrobial resistance (AMR) in resource-limited settings. This study characterized antibiotic-resistant bacteria (ARB) prevalence across manure–soil–vegetable pathways in Blantyre, Malawi. Using a cross-sectional design, we collected 35 samples (poultry/pig manure, farm/home soils, Brassica rapa subsp. chinensis, Brassica rapa, and Amaranthus spp.) from five livestock farms. Microbiological analysis with API 20E identification and disk diffusion testing revealed clear differences in contamination: Escherichia coli dominated pig manure (52%) and farm soil (35%), with detection in vegetables suggesting possible transfer (e.g., 20% in Brassica rapa subsp. chinensis), while Klebsiella pneumoniae contaminated all sample types (peak: 60% vegetables and 67% home soils). All manure isolates exhibited sulfamethoxazole–trimethoprim resistance, with 50% of pig manure E. coli showing cefotaxime resistance. Soil isolates mirrored these patterns (100% ampicillin resistance in K. pneumoniae and 77% cefotaxime resistance in farm soil E. coli). Vegetables displayed severe multidrug resistance (100% E. coli and 80% K. pneumoniae resistant to ≥3 classes), including critical gentamicin resistance (100% E. coli). Composting for ≤6 weeks, as practiced on the studied farms, did not eliminate ARBs, suggesting that longer durations may be needed. Notably, this study provides the first phenotypic evidence of presumptive Pasteurella-like organisms on edible leafy vegetables, specifically 45% in Amaranthus spp. and 6.1% in Brassica rapa, suggesting a potential zoonotic transmission route from livestock farms that requires molecular confirmation. These findings demonstrate manure-amended farms as AMR reservoirs, necessitating extended composting and antibiotic stewardship to mitigate One Health risks.

Urban and peri-urban farmers in Malawi increasingly use treated and untreated wastewater for vegetable production, but little is known about the extent of heavy metal accumulation in both exotic and indigenous vegetables, particularly with respect to differences between edible tissues (leaves vs. stems). This study addresses this gap by measuring the concentrations of cadmium (Cd), chromium (Cr), lead (Pb), zinc (Zn), and copper (Cu) in wastewater, soils, and six vegetables including three exotic and three indigenous irrigated with effluent from the Soche Wastewater Treatment Plant in Blantyre. Metal concentrations were determined using Atomic Absorption Spectrophotometry. Wastewater contained Zn (0.01 ± 0.001 mg/L) and Cu (0.02 ± 0.018 mg/L), both below World Health Organization (WHO) and Malawi Bureau of Standards (MBS) limits (Zn: 0.2 mg/L; Cu: 2 mg/L), while Cd, Cr, and Pb were below detection limit. In soils, Zn reached 56.4 ± 0.5 mg/kg, exceeding the WHO limit of 36 mg/kg; other metals remained within WHO permissible values. Vegetables showed species- and tissue-specific variation in metal accumulation: Cr reached 4.65 mg/kg in Cucurbita moschata stems, Cd up to 0.31 mg/kg in Amaranthus retro-flexus leaves, and Pb up to 4.09 mg/kg in Brassica rapa stems—all above FAO/WHO permissible limits (2.3, 0.2, and 0.3 mg/kg, respectively). Duncan’s post hoc analysis confirmed significant differences (p < 0.05) across matrices and plant parts, with leaves generally accumulating more Zn and Cu than stems. Principal component analysis (PCA) revealed that Zn, Cu, Cr, and Pb in the wastewater-soil-vegetable system largely share a common source, likely wastewater effluent and historical soil contamination, while Cd showed a more sporadic distribution, highlighting differential accumulation pathways. Health risk assessments revealed high Health Risk Index (HRI) values, with Brassica rapa stems (HRI = 92.3) and Brassica rapa subsp. chinensis leaves (HRI = 82.2) exceeding the safe threshold (HRI > 1), indicating potential chronic risks. This study reveals potential health risks associated with wastewater irrigation due to heavy metal accumulation in edible vegetables, and therefore recommends further research on metal speciation, seasonal variation, and bioaccumulation at different crop growth stages.

Malawi’s Blantyre City faces escalating waste management challenges due to increased urbanization and inadequate waste collection services. This research utilized remote sensing (RS) and geographic information system (GIS) techniques to map potential illegal dump sites (PIDSs). MODIS and Sentinel-5P satellite imagery and GPS locations of dumpsites were used to extract environmental and spatial variables, including land surface temperature (LST), the enhanced vegetation index (EVI), Formaldehyde (HCHO), and distances from highways, rivers, and official dumps. An analytical hierarchical process (AHP) pairwise comparison matrix was used to assign weights for the six-factor variables. Further, fuzzy logic was applied, and weighted overlay analysis was used to generate the PIDS map. The results indicated that 10.27% of the study area has a “very high” probability of illegal dumping, while only 2% exhibited a “very low” probability. Validation with field data showed that the GIS and RS were effective, as about 89% of the illegal dumping sites were identified. Zonal statistics identified rivers as the most significant contributor to PIDS identification. The findings of this study underscore the significance of mapping PIDS in low-resource regions like Blantyre, Malawi, where inadequate waste management and illegal dumping are prevalent. Future studies should consider additional factors and account for seasonal variations.

Background/objectives: Antimicrobial resistance (AMR) is a growing public health concern, and misuse of antibiotics in livestock farming contributes to its emergence. In Blantyre, Malawi, small-scale pig and poultry farming is widespread, but the knowledge, attitudes, and practices (KAP) driving antimicrobial use (AMU) remain poorly understood. This study aimed to assess the KAP regarding AMU and manure management among pig and poultry farmers in Blantyre, Malawi. Methods: This cross-sectional study surveyed 118 randomly selected farmers to assess AMU patterns, sources of antibiotics, adherence to withdrawal periods, disposal practices, and awareness of AMR and regulations. Data was collected using a structured questionnaire and analyzed with descriptive statistics and inferential tests (with statistical significance set at p < 0.05). Results: Antibiotic use was reported by 88% of farmers, primarily for therapy (93.3%) and prophylaxis (85.6%), including for viral diseases such as Newcastle disease in poultry and African swine fever in pigs. Oxytetracycline (91.5%), penicillin (50.8%), and trimethoprim-sulfamethoxazole (39.8%) were the most used antibiotics, predominantly sourced from agrovet shops (73.7%). While 61% of farmers knew antibiotic misuse could lead to AMR, significant gaps were observed: 68.6% had no formal training, 55.9% were unaware of regulations, and 42% sold/consumed products before the end of the withdrawal period. Most farmers disposed of expired antibiotics (80.5%) and packaging (92.4%) in household waste. Higher education and prior training were significantly associated with good knowledge. Conclusions: This study reveals significant knowledge–practice gaps and high-risk behaviors, such as misuse for viral diseases and unsafe disposal, that exacerbate AMR risks. Interventions must prioritize targeted farmer education, strengthening of veterinary extension services, and stricter regulation of agrovet shops to promote antimicrobial stewardship and support Malawi’s National Action Plan on AMR.

Background: Small scale poultry farming often involves intensive farming which includes the extensive use of antibiotics for growth promotion and disease prevention. This can be used as a focal point for understanding the spread of resistant bacteria among the livestock, human and the environment interface. This study aimed at unravelling the antimicrobial use and resistance in small scale poultry farmers in Blantyre, Malawi. Methods: Samples from chickens, humans and the environment were collected from various poultry farms to assess resistant profiles for Escherichia coli , Klebsiella pneumoniae , and Enterococcus species. Bacterial culturing and disc diffusion methods were used to isolate and assess the antimicrobial resistance (AMR) profiles of the isolated bacteria respectively. Logistic and linear regression tests were used to assess potential risk factors for the AMR. Results: The study revealed uniform resistance profiles of E. coli to ampicillin, cefotaxime, ciprofloxacin, gentamicin and sulfamethoxazole trimethoprim across samples from humans, chickens and their shared environment. The K. pneumoniae resistance profiles to sulfamethoxazole trimethoprim were higher in chicken and environmental samples compared to the human samples. The resistance profiles for Enterococcus species to vancomycin, linezolid, ciprofloxacin and tigecycline were similar across the three sample types. Nevertheless, E. coli and K. pneumoniae showed 100% sulfamethoxazole trimethoprim, while the Enterococcus species showed 80% resistance to vancomycin from all the three sample types. Farms that did not observe withdrawal periods were five times more likely to experience AMR (OR = 5.32, 95% CI: 1.89–14.94, p = 0.013) than the farms that observed withdrawal periods. Farms that had inadequate waste management practices were three times more likely to experience AMR (OR = 3.42, 95% CI: 1.22–9.59, p = 0.037) than the farms that had adequate waste management practices. Conclusions: The study confirms occurrence of AMR in the poultry farming, humans and the environment influenced by both biological and management factors. The similar resistance patterns across three sample types suggest a dynamic transmission of resistant bacteria at the human-animal-environment interface, hence emphasizing the need for a One health approach to mitigate AMR.