This study evaluated the efficacy of lytic phages on bacterial isolates of E. cloacae and determined their stability in various physicochemical conditions.Methods: Twenty-nine lytic phages were isolated from the waste water of six informal settlements in Nairobi County, Kenya, from July 2019 to December 2020 and cross-reacted with 30 anonymised clinical isolates of E. cloacae. Six phages were then selected for physicochemical property studies. Phages were described as potent upon lysing any bacterial strain in the panel.Results: Selected phages were stable at 4 °C -50 °C with a 5.1% decrease in titre in four of six phages and a 1.8% increase in titre in two of six phages at 50 °C. The phages were efficient following two weeks incubation at 4 °C with optimal activity at human body temperature (37 °C) and an optimal pH of 7.5. Phages were active at 0.002 M and 0.015 M concentrations of Ca 2+ ions. The efficiency of all phages decreased with increased exposure to ultraviolet light. All phages (n = 29) showed cross-reactivity against anonymised clinical isolates of E. cloacae strains (n = 30). The most potent phage lysed 67.0% of bacterial strains; the least potent phage lysed 27.0%. Conclusion:This study reveals the existence of therapeutic phages in Kenya that are potent enough for treatment of multi-drug resistant E. cloacae.
The problem of antimicrobial resistance has created a new need for alternative/ complementary treatments. To this end, bacteriophages offer an exciting prospect, as they can infect and kill specific bacteria without harming the host. This survey aimed to evaluate the state of applied phage research in Africa, among the members of the Africa phage Forum (APF). This was a cross-sectional survey whereby a google form was created for the members of the Africa Phage forum to fill so as to access the stage of phage research in Africa. Data was collected between June and July 2021 using a structured questionnaire form. A total of 65 out of a total of 101 forum members completed the questionnaire. The survey indicated that a majority 68% of phage researchers in Africa were at the training stages of their career. Some available participants were limited (8%). Most of the members identified funding, lack of skill set, near absence of adequate laboratory infrastructure as major hurdles for phage research. Despite these challenges, 73.3% of APF members work with the ESKAPE group with the majority of its members carrying out research in Phage in Biocontrol (80%), whereas others perform research related to human phage therapy (60%). However, it appeared this research has not yet reached the stage of commercialization. Overall, Phage research is in its infancy in Africa. Key challenges included poor laboratory infrastructure, lack of capacity building in the phage field, and lack of local awareness on the significance of phages for policymakers and governments. APF could, therefore, play a role in creating phage awareness in Africa; mobilizing resources; enhancing networks and collaborations amongst APF members and beyond, especially with more experienced phage mentors in the Western countries, to greatly reduce the gap in knowledge and enhance phage research in Africa.
Objectives: Escherichia coli and some Salmonella enterica serovars are zoonotic pathogens affecting livestock and humans. These pathogens cause significant loss of productivity in livestock, severe morbidity and mortality in humans, and have high antibiotic resistance profiles. Therefore, the exploitation of lytic phages for therapeutic purposes is important for eliminating these resistant bacterial strains.Methods: Thirty-four bacterial stock isolates comprised of 23 E. coli and 11 Salmonella spp. strains were evaluated for antimicrobial susceptibility to seven antibiotics using the Kirby-Bauer disk diffusion test. The antibiotics included Ciprofloxacin, Trimethoprim-Sulphamethoxazole, Gentamycin, Imipenem, Ceftriaxone, Cefotaxime, and Ofloxacin. Twelve (12/23) E. coli and (2/11) Salmonella spp. exhibited antimicrobial resistance. Selected six (6/12) drug-resistant E. coli strains were subjected to three different phages (PA5, EHEC005, C11S1A) for efficacy and host range assay. Similarly, two (2/2) resistant Salmonella strains were exposed to one Salmonella phage A23 for efficacy and host range assay. The E. coli (C11S1A) phage, which infected most bacterial hosts, was evaluated for optimal efficiency at various pH and temperatures.Results: E. coli isolates had the highest resistance 12/23 (52%) compared to Salmonella spp. 2/11(18%) (p<0.05). Most resistance was against Trimethoprim-Sulphamethoxazole (44%) and (9%) for E. coli and Salmonella spp., respectively. Furthermore, E. coli (C11S1A) phages killed all the Escherichia coli strains, while Salmonella phage A23 only lysed the host bacteria. The E. coli (C11S1A) phages were highly efficacious at 37 0 C and pH 7.4. Conclusion:The successful isolation of novel lytic E. coli (C11S1A) phages, which killed all the E. coli strains tested, demonstrates the potential for therapeutic purposes for humans and livestock.
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