Bacteria, Volume 4, Issue 1 (March 2025) – 5 articles

Phosphorus is a macronutrient crucially important for plant growth and development; its limited amount in soil and water poses bewildering concerns amongst agronomists. Externally applied phosphorus fertilizers can fulfil crops’ phosphorus needs throughout essential growth stages; however, the overapplication of phosphorus fertilizers leads to diminished phosphorus acquisition efficiency (PAE), disrupts the delicate balance of nutrients in soil and water, leads to deficiencies in other essential elements, poses significant environmental risks, and accelerates the loss of phosphorus mineral supplies. Moreover, much of the applied phosphorus may become fixed as insoluble phosphates by combining with calcium, iron, aluminum, manganese, etc., present in soil, making it unavailable for the plants. Phosphate solubilizing bacteria (PSB) can render insoluble phosphate accessible to plants by solubilization and mineralization, hence enhancing crop yields while ensuring environmental sustainability. Earthworms are vital soil invertebrates that interact continuously with soil and soil microorganisms and play an essential role in maintaining soil fertility. The present study aims to screen and identify potential phosphate solubilizing bacteria from the intestinal tract of the earthworm Aporrectodea rosea. The experimental results indicate that the strain PSEG-1 was effective in phosphate solubilization, with a solubilization index of 1.6 in Pikovskaya (PVK)’s medium. The strain produced organic acid in the National Botanical Research Institute (NBRIP)’s medium. Phenotypic and genotypic studies of the isolate showed that the strain PSEG-1 belongs to Klebsiella variicola. Our results suggest that the vermi-bacterial strain Klebsiella variicola PSEG-1 possesses intrinsic abilities to solubilize phosphate, which could be exploited for formulating potential microbial biofertilizers to enhance crop production. Full article

This study aimed at systematically exploring the seasonalities of bacterial identifications from 1 February 2014 to 31 January 2020 in hospitalized patients, considering the infectious site and the community-acquired or hospital-associated origin. Bacterial identifications were extracted from the data warehouse of the Institut Hospitalo-Universitaire Mediterranée Infection surveillance system, along with their epidemiological characteristics. Each species’ series was processed using a scientific workflow based on the TBATS time series model. Possible co-seasonalities were researched using seasonal peak clustering and series cross-correlations. In this study, only the 15 most frequent species were described in detail. The three most frequent species were Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis, with median weekly incidences of 145, 74, and 39 cases, respectively. Samplings of S. aureus and E. coli follow the same seasonal dynamics. S. aureus hospital-associated infections exhibited a significant association with temperature, humidity, and pressure change, whereas community-acquired infections were only associated with precipitations. More seasonal peaks were observed during the winter season. Among the 15 peaks of this seasonal maximum, 6.7% came from blood (Klebsiellia oxytoca) and 13.3% from respiratory specimens (E. coli and S aureus). Our results showed significant associations of periodicity between pathogens, origin of infection, type of sampling, and weather drivers. Full article

This research is focused on assessing the antibacterial properties of Pogostemon benghalensis stem bark and inflorescence extracts, as well as their inhibitory effects on xanthine oxidase, antioxidant potential, overall phenolic content, and flavonoid concentration. The cold maceration technique was used to obtain extracts using water, methanol, and ethyl acetate solvents. The disk diffusion method demonstrated the significant antibacterial efficacy of the methanol stem bark extract against Staphylococcus epidermidis, with a zone of inhibition (ZOI) of 13 mm, and the inflorescence methanol extract against Klebsiella pneumonia (ZOI: 12.9 mm). Moreover, the methanol stem bark extract exhibited the minimum bactericidal concentration (MBC) at 1.56 mg/mL and the minimum inhibitory concentration (MIC) at 0.78 mg/mL against S. epidermidis. The ethyl acetate inflorescence extract displayed noteworthy xanthine oxidase inhibition (IC₅₀: 29.1 µg/mL) comparable to allopurinol (IC₅₀: 12.7 µg/mL). Furthermore, the methanol stem bark extract exhibited a remarkable DPPH free radical inhibitory effect, showing an IC₅₀ value of 42.5 µg/mL. The total polyphenol content ranged from 29.9 μg to 161.3 µg GAE per mg of dried extract weight in the methanol inflorescence extract, while the total flavonoid content ranged from 38.4 μg to 96.8 μg QE per mg of dried extract weight within the water-derived extract. Overall, these findings demonstrate the potent antibacterial properties, xanthine oxidase inhibition, and antioxidant activity of P. benghalensis extracts. Full article

To safeguard against microbial diseases and maintain optimal silk yields, the sericulture industry relies on antibiotics to promote the health, well-being, and vitality of silkworms (Bombyx mori). Antibiotics are commonly incorporated into synthetic diets for rearing silkworms or included as key components in bed disinfectant formulations. The silkworm-rearing industry’s reliance on antibiotics has led to concerns about the development of antibiotic-resistant bacteria. Previous research has uncovered a dual role for antibiotics: not only do they prevent disease, but they also promote silkworm growth by reshaping the gut microbiome and enhancing nutrient absorption, highlighting the need for judicious use. Therefore, there is a critical need for prudent management and further exploration of alternative growth-promoting strategies to minimize resistance risks. This study investigates the relationship between antibiotic administration and silkworm growth, shedding light on the mechanisms underlying antibiotic-induced effects and assessing the risk of antimicrobial resistance (AMR) emergence and dissemination. Full article

The cat oral microbiome plays an important role in maintaining host health, yet little is known about how to apply microbial data in a clinical setting. One such use of microbiome signatures is in cases of feline chronic gingivostomatitis (FCGS), a severe debilitating complex disease of the oral cavity. FCGS-afflicted cats have limited treatment options, and individual patient responses to treatment are needed. In this work, we used deep sequencing of total RNA of the oral microbiome to chronicle microbial changes that accompanied an FCGS-afflicted cat’s change from treatment-non-responsive to treatment-responsive within a 17-month span. The oral microbiome composition of the two treatment-non-responsive time points differed from that of the treatment-responsive point, with notable shifts in the abundance of Myscoplasmopsis, Aspergillus, and Capnocytophaga species. Intriguingly, the presence of the fungal groups Aspergillus and Candida primarily differentiated the two non-responsive microbiomes. Associated with responder status were multiple Capnocytophaga species, including Capnocytophaga sp. H2931, Capnocytophaga gingivalis, and Capnocytophaga canimorsus. The observation that the oral microbiome shifts in tandem by response to treatment in FCGS suggests a potential use for microbiome evaluations in a clinical setting. This work contributes to developing improved molecular diagnostics for enhanced efficacy of individualized treatment plans to improve oral disease. Full article