Comparative Physicochemical and Microbiological Qualities of Source and Stored Household Waters in Some Selected Communities in Southwestern Nigeria

Monitoring Multi-Drug Resistant Klebsiella pneumoniae in Kitagata Hot Spring, Southwestern Uganda: A Public Health Implication

Background

The concerning frequency of K. pneumoniae in various recreational settings, is noteworthy, especially regarding multi-drug resistant (MDR) strains. This superbug is linked to the rapid spread of plasmids carrying these resistance genes. The objective of this study was to evaluate the spatiotemporal prevalence of MDR-K. pneumoniae in the Kitagata hot spring, Southwestern Uganda.

Methods

A laboratory-based descriptive longitudinal study was conducted between May and July 2023. During rainy and dry seasons, we collected eighty water samples in the morning and evening from the hot spring. The temperature at each point was measured prior to sample collection, and two samples were obtained at varying depths. 5 mL of each homogenized sample were pre-enriched in brain heart infusion broth, and subsequently in both blood and violet red bile agar. The Kirby-Bauer disk diffusion method was performed, followed by the detection of carbapenemase (CR) and extended-spectrum β-lactamase (ESBL) production. Polymerase chain reaction showed resistance genes viz. bla TEM, bla CTX-M and bla KPC. Data were analyzed using SPSS-20 to obtain chi-square tests and regression analysis.

Results

K. pneumoniae accounted for 30.0% of isolates obtained from Kitagata hot springs, with all isolates classified as multi-drug resistant. All isolates were resistant to ampicillin, rifampicin, ceftazidime, and azithromycin (79.2%). Additionally, 95.8% of isolates harbored bla TEM gene alone and both bla TEM and bla CTX genes, followed by bla KPC alone (33.3%), with 25% harboring all three resistance genes. During the dry season, K. pneumoniae had a higher prevalence (35.0%) compared to the wet season (25.0%). The prevalence of MDR-K. pneumoniae significantly increased over the course of the study. The presence of the three studied resistance genes in the isolates showed a positive correlation with the second phase of sample collection and the dry season but exhibited a negative correlation with temperature, except for isolates harboring either bla TEM alone or bla TEM+KPC+CTX genes.

Conclusion

Kitagata hot spring serves as a hotspot for continuous dissemination and acquisition of MDR-K. pneumoniae harboring resistance genes that encode for ESBL and CR production. The healthcare sector ought to implement an ongoing monitoring and surveillance system as well as robust antimicrobial resistance stewardship programs aimed at delivering health education to the community.

Seasonal Shift in Physicochemical Factors Revealed the Ecological Variables that Modulate the Density of Acinetobacter Species in Freshwater Resources

Certain environmental variables are responsible for the survival of microorganisms in aquatic environments. The influence of these environmental factors in each season (winter, autumn, spring and summer) of the year can be used to track changes in a microbial population in freshwater resources. In this study, we assessed the effect of seasonal shifts in environmental variables including temperature, pH, total dissolved solids (TDS), total suspended solids (TSS), biochemical oxygen demand (BOD) and turbidity (TBS) among others on the density of Acinetobacter species in the Great Fish, Keiskamma and Tyhume rivers in the Eastern Cape Province, South Africa. Water samples and values of the environmental factors were taken from the rivers for 12 months. The density of presumptive Acinetobacter species was estimated from the culture of water samples on a CHROMagar selective medium, while the Acinetobacter-specific recA gene was targeted for the identification of Acinetobacter species using PCR assay. The multivariate relationship between seasons and changes in variables was created using PCA, while the effect of seasonal shifts in the environmental variables on the density of Acinetobacter species was evaluated using correlation test and topological graphs. Positive association patterns were observed between the seasons, environmental factors and the bacterial density in the rivers. In addition, temperature, TBS, TSS and BOD tended to influence the bacterial density more than other physicochemical factors in the rivers across the seasons. Of the total 1107 presumptive Acinetobacter species, 844 were confirmed as Acinetobacter species. Therefore, these findings suggested that the rivers contain Acinetobacter species that could be useful for basic and applied study in ecology or biotechnology, while their clinical relevance in causing diseases cannot be underestimated.

Response surface methodology mediated optimization of Indanthrene Blue RS by a novel isolated bacterial strain Bacillus flexus TS8

The enhanced decolorization and detoxification of Indanthrene Blue RS dye, under aerobic conditions, by a novel isolated anthraquinone-degrading bacterium, Bacillus flexus TS8, has been presented in this paper. The optimal decolorization conditions were determined by response surface methodology based on Box-Behnken design. The results indicated that the strain TS8 possessed the highest decolorization efficacy at pH 10.26, temperature 30.97 ºC and an inoculum size of 10.48% (v/v). It also revealed that about 98.01% of 100 mg/L of Indanthrene Blue RS could be decolorized within 24 hr under these optimized conditions. The subsequent degradation of the dye and the formation of metabolites were studied using analytical techniques such as UV-Vis spectroscopy, FTIR, and ESI/LC-MS analysis. The UV-Vis analysis of the colorless bacterial cells demonstrated that Bacillus sp. TS8 possessed this decolorizing activity through biodegradation. The degraded products obtained from ESI/LC-MS analysis were identified as 1-hydroxyanthracene-9, 10-dione (m/z-224), 1, 4-di-hydroxyanthracene-9, 10-dione (m/z-240), and phthalic acid (m/z-168). This study investigated the highest decolorization efficacy of strain TS8 to be utilized in the biological treatment of wastewaters containing anthraquinone dyes. PRACTITIONER POINTS: Enhanced decolorization of anthraquinone dye wastewater. Ninety-eight percentage of dye decolorization was obtained within 24 hr. Optimization of process parameters through the response surface methodology. ESI/LC-MS analysis identified phthalic acid as the end product of Indanthrene Blue RS degradation. Degradation pathway for Indanthrene Blue RS is outlined.

A culture-dependent and metagenomic approach of household drinking water from the source to point of use in a developing country

Rural households in developing countries rely on communal water supplies and household water frequently becomes contaminated following its collection, transportation and during its storage. Using culture-dependent and -independent techniques, we examined the changes in microbial water quality between communal tap water and household water storage in a rural area of Cameroon, Africa. The culturable fecal indicator bacteria (FIB) were used to assess the potential health risks associated with different household water storage conditions (e.g., type of container and open vs. closed container) and interventions (e.g., water storage days, cleaned on the last day of use, and hygiene practices). Only the amount of days the water was stored significantly differed (p-value < 0.05), which showed that potential health risks increased when water was stored for more than 3 days. The higher abundance of molecular FIB in biofilm than household water suggested that omnipresent biofilm in household water could potential health risk. The high-throughput sequencing revealed that the most abundant phylum was Proteobacteria, followed by Actinobacteria and Bacteroidetes in both the water and the biofilm samples. Bacterial genera seen in biofilm bacteria, such as Pseudomonas, Acinetobacter and Comamonas. Acinetobacter, Chryseobacterium, Stenotrophomonas and Corynebacterium, were relatively more abundant in the biofilm than in the water. Potential bacterial pathogens including Acinetobacter baumannii, Citrobacter freundii, Stenotrophomonas maltophilia and Haemophilus influenza, were detected in household water and biofilm. The microbial quality might be affected by water-storage time and households repeatedly using the same water storage containers without proper sanitization, triggering microbial regrowth and biofilm formation on water containers. Higher bacterial diversity and potentially pathogenic bacteria found in the biofilm samples of a household water supply are unhealthy for the house's inhabitants. It is important to develop interventions aimed at preventing the formation of these dangerous biofilms in a communal water supply.

Microbiological and Physicochemical Water Quality Assessments of River Water in an Industrial Region of the Northwest Coast of Borneo

Urbanization and ever increasing socioeconomic activities have degraded natural resources globally. This study monitored water quality (WQI) based on physicochemical and microbial qualities of river water in an industrial region northwest coast of Borneo. Microbiological parameters tested included total viable count (TVC), coliform count (TC), faecal coliform count (FC), and Escherichia coli confirmation. Physicochemical constituents evaluated included water temperatures (T), pH, total dissolved solids (TDS), salinity, electrical conductivity (EC), dissolved oxygen (DO), biochemical oxygen demand (BOD), ammoniacal nitrogen (NH3-N), chemical oxygen demand (COD) and total suspended solids (TSS). The mean microbial counts of samples were: TVC (3.9 × 102–3.0 × 104 cfu mL−1), TC and FC (23–>1600 MPN 100 mL−1) (MPN: the most probable number) and Escherichia coli growth was confirmed. The mean values of pH, TDS, salinity, EC and BOD are significantly different (p < 0.05) between the rivers ranged: pH (5.05 ± 0.03–6.10 ± 0.10), TDS (0.0 ± 0.0–38,600 ± 50 mg L−1), salinity (0.01 ± 0.0–3.07 ± 0.07%), EC (650 ± 25–19,566.67 ± 251.66 µS cm−1), and BOD (0.23 ± 0.10–3.12 ± 0.02 mgO2 L−1). The tested parameters of samples exceeded international limits with the exception of COD and TSS. The WQI of river water tested ranged from 65–73 under class III. Most of the river water was slightly polluted and a potential threat to public health.