Lytic Bacteriophage as an Alternative to Antibiotics for Controlling Multidrug-Resistant Bacteria Isolated from Human, Animal, and Environmental Samples in Tanzania

Abstract

Background: The rise of multidrug-resistant bacteria poses a significant global health threat, outpacing the development
of new antibiotics and potentially reverting medical practices to a pre-antibiotic era. Despite advancements in antibiotic
therapies for various diseases, rising antibiotic resistance rates have shifted focus towards alternative treatments, including
the use of bacteriophages, capable of targeting antibiotic-resistant bacteria. Therefore, this study aimed to investigate the
use of lytic bacteriophages as an alternative to antibiotics in controlling bacteria isolated from clinical and environmental
samples in Moshi, Kilimanjaro, Tanzania.
Methodology: A cross-sectional study was conducted from May to July 2023, involving clinical and environmental
components. Clinical bacterial isolates were obtained from Kilimanjaro Christian Medical Centre (KCMC), while
environmental bacteria were collected from soil, animal waste, and wastewater samples. Standard microbiological
methods were used for bacterial isolation, identification, and antimicrobial susceptibility testing. Bacteriophages were
isolated from wastewater samples using enrichment techniques, and their lytic activity was evaluated against bacterial
isolates by spot assays. Data were analysed using descriptive statistics to summarise the distribution of bacterial isolates
and bacteriophage activity across different sample types.
Results: A total of 7, 20, 16, and 26 bacterial isolates were obtained from clinical samples, soil, animal waste,
and wastewater, respectively. The predominant bacterial species included Escherichia coli, Pseudomonas aeruginosa,
Klebsiella pneumoniae, and Staphylococcus aureus. Bacteriophages isolated from wastewater showed lytic activity
against bacteria from soil, animal waste, and clinical samples, with activity mainly observed at lower dilutions (10⁰
10⁻²). A decline in bacteriophage activity was observed with increasing dilution, with most isolates showing resistance
at higher dilutions (≥10⁻³). Environmental isolates were generally more susceptible to bacteriophage activity compared
to clinical isolates.
Conclusion: Bacteriophages isolated in this study exhibited lytic activity against multidrug-resistant bacteria from
environmental and clinical sources, particularly at lower dilutions. These findings suggest their potential as alternative or
adjunct antibacterial agents within a One Health framework. However, further molecular characterisation and in vivo
studies are required before therapeutic application.