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Antimicrobial resistance (AMR) is one of the top 10 global health threats facing humanity, and the sub-Saharan Africa (SSA) is among the heavily affected regions due to its weak health systems and limited resources. Due to an escalating number of AMR pathogens and the scarcity of new antimicrobials, efforts in the prevention of infections and the search for alternative treatment options are ongoing. The objective of this review was to assess important weapons against AMR in SSA. The highlighted weapons include vaccines, education and awareness, infection prevention and control (IPC) using water, sanitation, and hygiene (WASH), alternative treatment options, the One Health (OH) approach, AMR surveillance, operational national action plans (NAPs) on AMR, antimicrobial stewardship (AMS) programs, and good governance and regulations. Despite not being used at a satisfactory level in SSA, advanced techniques in dealing with AMR in SSA include (i) metagenomics, (ii) whole-genome sequencing (WGS) in AMR surveillance to track resistance trends and know when to intervene, and (iii) use of artificial intelligence in AMR prediction based on genomics data. The fight against AMR threat in SSA has embraced a number of currently available strategies, and developing new ones will lower the consequences of such a threat for future generations.

In contemporary times, the sustained aspiration of bioengineering and biomedical applications is the progressive advancement of materials characterized by biocompatibility and biodegradability. The investigation of the potential applications of polymers as natural and non-hazardous materials has placed significant emphasis on their physicochemical properties. Thus, this study was designed to investigate the potential of gelatin–chitosan–moringa leaf extract (G–CH–M) as a novel biomaterial for biomedical applications. The wound-dressing G–CH–M biopolymer was synthesized and characterized. The blood haemolysis, anti-inflammatory, antioxidant, and antibacterial activities of the biopolymer were investigated against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial isolates. Our results showed that S. aureus swarming motility was drastically affected. However, the biopolymer had no significant effect on the swarming motility of E. coli. In addition, the biopolymer showed high antibacterial capacities, especially against S. aureus. Plasmid DNA was observed to be effectively protected from oxidative stresses by the biopolymer. Furthermore, the biopolymer exhibited greatly suppressed haemolysis (lower than 2%), notwithstanding the elevated concentration of 50 mg/mL. These results indicated that this novel biopolymer formulation could be further developed for wound care and contamination prevention.

S. aureus is the pathogen that is commonly associated with subclinical mastitis, causing significant economic losses to dairy farms. This infection responds poorly to antimicrobial treatment, which could be due to the development of AMR, biofilm formation, and the intracellular invasion of S. aureus into bovine mammary cells leading to treatment failure. Thus, it is important to understand the challenge of this problem. Therefore, the present study aims to determine the prevalence, antimicrobial resistance, and characterization of S. aureus that was isolated from subclinical bovine mastitis in East Coast Malaysia. A total of 235 milk samples from dairy cows were collected from selected farms in Kelantan and Pahang. The samples were subjected to a somatic cell analysis to identify subclinical mastitis, followed by bacteria isolation and antimicrobial susceptibility testing. The isolated S. aureus were further analyzed for their ability to form biofilms and invade the bovine mammary epithelial cells (MAC-T cells) in in vitro infections modeling using a gentamicin protection assay. The overall total of 74/235 (31.4%; 95% CI = 0.31; 0.32) of the milk samples demonstrated >200,000 somatic cells/mL, suggesting the presence of subclinical mastitis in the animals. A total of 39/235 (16.5%; 95% CI = 0.16, 0.17) of the milk samples harbored S. aureus which demonstrated resistance towards the following antimicrobials: penicillin (18/39, 46%), ampicillin (17/39, 43.6%), oxacillin (12/39, 31%), tetracycline (10/39, 26%), and erythromycin (7/39, 18%). AMR was recorded for a total of (17/39, 43.6%) of S. aureus isolates. All isolates formed biofilms, with (8/30, 27%) strongly biofilm-forming, (18/30, 60%) moderately biofilm-forming, and the remaining (4/30, 13%) of isolates weakly biofilm-forming. Interestingly, the AMR isolates appear to produce weak and moderate biofilm. Moreover, (6/20, 30%) of the S. aureus isolates were invasive towards MAC-T cells, as indicated by their ability to evade gentamicin treatment. The study demonstrated the presence of AMR, invasiveness, and biofilm formation in S. aureus that was isolated from subclinical mastitis. This characteristic presents additional challenges to existing antimicrobial therapy.

Staphylococcus aureus is an ubiquitous and versatile pathogen associated with a wide range of diseases. In animals, this bacterium is one of the causative agents of bovine mastitis, responsible for huge economic losses in the dairy industry. Besides the development of antibiotic resistance, the intracellular survival of S. aureus within udder cells has rendered many antibiotics ineffective, leading to therapeutic failure. Our study therefore aims to investigate the in vitro bactericidal activity of ikarugamycin (IKA) against intracellular S. aureus using a bovine mammary epithelial cells (Mac-T cells) infection model and determine the cytotoxic effect. Minimum inhibitory concentration (MIC) was used to determine the antibacterial activity of IKA, and Mac-T cells were infected with S. aureus using gentamicin protection assay. IKA intracellular antibacterial activity assays were used to determine the bactericidal activity of IKA against intracellular S. aureus. The cytotoxicity of IKA against Mac-T cells was evaluated using the resazurin assay. We showed that, S. aureus is susceptible to IKA with a MIC value of 0.6 μg/mL. IKA at 4 × MIC and 8 × MIC have bactericidal activity by reducing 3 and 5 logs10 CFU/mL of S. aureus in the first six-hour of treatment respectively. In addition, IKA demonstrated intracellular killing activity by killing 90% of intracellular S. aureus at 5 μg/mL. This level is comparatively lower than 9.2 μg/mL determined as the half-maximal inhibitory concentration (IC50) of IKA required to kill 50% of Mac-T cells, highlighting a lower concentration required for bactericidal effect compared to the cytotoxic effect. The study highlighted that importance of IKA as a potential antibiotic candidate to be explored for the in vivo efficacy in treating S. aureus mastitis.

Salmonella species (spp.) and Escherichia coli (E. coli) are the most common infectious pathogens in poultry. Antimicrobials are given either as growth promoters or as treatment, thereby increasing the possibility of the emergence of antimicrobial resistance (AMR). We determined the prevalence of AMR for both pathogens isolated from broiler farms in the East Coast of Peninsular Malaysia from 2018–2019. A total of 384 cloacal swabs were collected, followed by bacterial isolation, confirmation, and antimicrobial susceptibility tests. The overall prevalence of Salmonella spp. and E. coli were 6.5% and 51.8%, respectively. Salmonella spp. and E. coli displayed resistance towards the following antimicrobials: erythromycin (100% for both pathogens), chloramphenicol (76.2% and 84.5%, respectively), tetracycline (62% and 94.6%, respectively), ampicillin (47.7% and 87%, respectively), sulfamethoxazole/trimethoprim (42.9% and 83.3%, respectively), ciprofloxacin (4.8% and 23.8%, respectively), nalidixic acid (9.6% and 60.7%, respectively), streptomycin (19% and 66%, respectively), kanamycin (28.6% and 57%, respectively), cephalothin (0% and 11%, respectively), and gentamicin (0% and 20.2%, respectively). Multidrug resistance (MDR) was recorded in 82% of Salmonella spp. and 100% of E. coli. These findings demonstrate the high prevalence of AMR in both pathogens in broiler farms on the East Coast of Peninsular Malaysia. These findings could be attributed to the excessive use of antimicrobial agents by poultry farm owners. Enhanced control measures and a strong monitoring system should be urgently implemented in order to reduce the emergence of antimicrobial resistance.