Bacteria, Volume 2, Issue 1 (March 2023) – 6 articles

The establishment of Permanent Preservation Plots (PPPs) in natural forests has a signifi-cant role in assessing the impact of climate change on forests. To pursue long-term studies on cli-mate change, PPPs were established during the year 2016 in two major forest areas in Bangalore to conduct ecological studies to monitor the vegetation changes. One of the objectives of the study was to understand the drivers of diversity, such as soils, in terms of nutrients and physical and biological properties. The native tropical forest of Bangalore, which houses Bannerghatta National Park (BNP) on the outskirts, is relatively underexplored in terms of its microflora, particularly arbuscular my-corrhizal fungi (AMF). Hence, the present study was aimed at the quantitative estimation of arbus-cular mycorrhizal fungi (AMF) in the three 1-ha PPPs which were established in Bannerughatta National Park (BNP) and Doresanipalya Reserve Forest (DRF) as per the Centre for Tropical Forest Sciences (CTFS) protocol. In BNP, two plots were established, one in the Thalewood house area (mixed, moist, deciduous type) and the other in the Bugurikallu area (dry, deciduous type). In DRF, one plot was established in dry, deciduous vegetation. Each one-hectare plot (100 m × 100 m) was subdivided into twenty-five sub-plots (20 m × 20 m). Composite soil samples were collected during two seasons (dry and wet) and analyzed for AMF spore and available phosphorus (P) content. The results revealed the presence of AMF in all the three plots. Doresanipalya plo had the highest spore number, followed by the Bugurikallu plot and Thalewood house plot. The available phosphorous and AMF spore numbers showed correlations in all the three plots. Among the AMF spores, the Glomus species was found to dominate in all the three plots. The study shows that the dry, decidu-ous forests accommodated more AMF spores than the mixed, moist forests. Full article

Antimicrobial resistance (AMR) is a global public health threat. Quality data on AMR are needed to tackle the rise of multidrug-resistant clones. These data are rare in low-income countries, especially in sub-Saharan Africa. In this study, we investigated the rise of extended-spectrum β-lactamase–producing (ESBL) Enterobacteriaceae in Bangui, Central African Republic. We collected 278 fecal samples from 0–5-year-old children admitted to the Pediatric University Hospital Complex in Bangui from July to September 2021. Enterobacteriaceae were isolated and identified, and their susceptibility to 19 antibiotics was tested. We recovered one and two Enterobacteriaceae species from 208 and 29 samples, respectively. One clone of each species from each sample was further characterized, for a total of 266 isolates. Escherichia coli predominated, followed by Klebsiella. AMR was frequent, with 98.5% (262/266) of the isolates resistant to at least one antibiotic. Additionally, 89.5% (238/266) of the isolates were multidrug resistant, with resistance being frequent against all tested antibiotics except carbapenems and tigecycline, for which no resistance was found. Importantly, 71.2% (198/278) of the children carried at least one ESBL species, and 85.3% (227/266) of the isolates displayed this phenotype. This study confirms the rise of ESBL Enterobacteriaceae in Bangui and stresses the need for action to preserve the efficacy of antibiotics, as crucial for the treatment of bacterial infections. Full article

Traditional preparation of African indigenous vegetables (AIVs) such as African black nightshade (Solanum nigrum) and African spiderplant (Cleome gynandra) involves either boiling and discarding the first water or lengthy boiling. Fermentation is considered a better alternative processing technique due to the enhanced retention of phytochemical contents and sensory properties. However, little is known about the impact of lactic acid fermentation on the phytochemical content, antioxidant capacity, sensory acceptability and microbial safety of the African black nightshade and African spiderplant. This study aimed to ferment AIVs using combined starter cultures (Lactobacillus fermentum and Lactococcus lactis) and further determine their effect on the phytochemical content (phenolic compounds and flavonoids), antioxidant capacity, sensory acceptability and microbial safety of the vegetables. There was a marked increase in phenol and flavonoid contents in all fermented vegetables (p < 0.05). The highest phenol content was 228.8 mg/g GAE (gallic acid equivalent) in the starter-culture-inoculated African black nightshade, while flavonoid content was 10.6 mg/g QE (quercetin equivalent) in the same. Starter-culture-inoculated AIVs presented significantly higher antioxidant capacity with a 60–80% radical scavenging activity compared to levels in uninoculated batches (p < 0.05). Fermented vegetables were more liked than the boiled vegetables and were microbiologically safe. In conclusion, lactic fermentation of AIVs increased phytochemical contents (phenolic compounds and flavonoids), maintained antioxidant capacity and improved product safety and sensory acceptability. Therefore, fermentation and consumption of the African indigenous vegetables are to be encouraged. Full article

Salmonella enterica is the principal causative agent of salmonellosis, a threat to human health. Because of its high antimicrobial resistance potential, Salmonella enterica has become worrisome, mostly in developing countries where hygiene and antimicrobial usage are defective. This study aimed to determine the epidemiology of the intestinal carriage of Extended Spectrum β-Lactamase producing Salmonella enterica from chickens and poultry farmers in Dschang, a town in the western region of Cameroon. A total of 416 chickens and 72 farmers were sampled between May and October 2020; and Salmonella enterica were isolated and subjected to extended spectrum β-lactamase screening. Logistic regression was used to test for statistical associations using a p-value of ≤0.05. Results from this study revealed that the prevalence of the intestinal carriage of Salmonella enterica for chickens and farmers were 55.77% [51.00; 60.54] and 22.22% [12.62; 31.82], respectively. Meanwhile, the intestinal carriage of Extended Spectrum β-Lactamase producing Salmonella enterica was 23.08% [13.76; 32.40] and 5.55% [0.26; 10.84] from chickens and poultry farmers, respectively. The risk factor for this carriage was revealed to be lack of knowledge by actors in livestock industries of antibiotic resistance. Chickens, just like poultry farmers, represent the starting point of community salmonellosis, which is difficult to cure; therefore, sensitization of breeders is an effective tool for the mitigation of this burden. Full article

Bacterial proteases participate in the proteolytic elimination of misfolded or aggregated proteins, carried out by members of the AAA+ protein superfamily such as Hsp100/Clp, Lon, and FtsH. It is estimated that the Clp and Lon families perform around 80% of cellular proteolysis in bacteria. These functions are regulated, in part, through the spatial and/or temporal use of adapter proteins, which participate in the recognition and delivery of specific substrate proteins to proteases. The proteolysis plays an important role in maintaining and controlling the quality of the proteins, avoiding the accumulation and aggregation of unfolded or truncated proteins. However, this is not their only function, since they play an important role in the formation of virulent phenotypes and in the response to different types of stress faced when entering the host or that occur in the environment. This review summarizes the structural and functional aspects of the Clp proteases and their role in Gram-positive microorganisms. Full article

African indigenous leafy vegetables (AILVs) are plants that have been part of the food systems in Sub-Saharan Africa (SSA) for a long time and their leaves, young shoots, flowers, fruits and seeds, stems, tubers, and roots are consumed. These vegetables are high in vitamins, minerals, protein, and secondary metabolites that promote health. This study aimed at isolating, characterizing, and identifying dominant lactic acid bacteria (LAB) from naturally fermenting commonly consumed AILV in Kenya. A total of 57 LAB strains were isolated and identified based on phenotypic and 16S rRNA gene analyses from three AILVs (23 nightshade leaves, 19 cowpeas leaves, and 15 vegetable amaranth). The highest microbial counts were recorded between 48 h and 96 h of fermentation in all AILVs ranging from approximately log 8 to log 9 CFU/mL with an average pH of 3.7. Fermentation of AILVs was dominated by twenty eight Lactobacillus spp. [Lactiplantibacillus plantarum (22), Limosilactobacillus fermentum (3), Lactiplantibacillus pentosus (2) and Lactiplantibacillus casei (1)], eleven Weissella spp. (Weissella cibaria (8), W. confusa (2), and W. muntiaci) six Leuconostoc spp. [Leuconostoc mesenteroides (3), Leuc. citreum (2) and Leuc. lactis (1)], six Pediococcus pentosaceus, four Enterococcus spp. [Enterococcus mundtii (2), E. faecalis (1) and E. durans (1)] and, finally, two Lactococcus garvieae. These bacteria strains are commonly used in food fermentation as starter cultures and as potential probiotics. Full article