Introduction: Allium sativum has been known to possess various medicinal properties, including antibacterial activity. This study was designed to evaluate and quantify killing kinetics of Allium sativum. Allium sativum in vitro time-kill kinetics antibacterial investigation was evaluated by plate count technique and analyzed by percentage and log reduction against Pseudomonas aeruginosa and Staphylococcus aureus.Methods: Ethanolic extract of A. sativum was prepared and tested against Pseudomonas aeruginosa and Staphylococcus aureus. The kinetics of killing and re-growth of the bacteria were then assessed as functions of both time and the extract concentration. Results: The time kill-kinetics of Allium sativum ethanol against the test organisms showed that the extract achieved 100% killing at 1 mg/ml against the two test organisms after 12 h of contact. All test organisms were susceptible to the ethanolic extract. Average log reductions in viable cell counts for the extract ranged between 0.02log10 and 1.20log10 cfu/ml for P. aeruginosa and 0.03log10 and 0.97log10 cfu/ml for S. aureus after 10 h interaction at 0.5mg/ml and 1mg/ml. The extract was rapidly bactericidal at 1mg/ml achieving a complete elimination of the two test organisms within 12 h exposure. Conclusion: Overall, this quantified information on time-kill kinetics may provide an initial step towards understanding in vitro pharmacodynamics of antibacterial activity of A. sativum.

Enterococcus spp. are common but not predominant commensal bacteria that inhabit the gastrointestinal tracts of humans and animals and are widely distributed in various environmental matrices and diverse food sources. Multiple strains of beneficial enterococci are increasingly utilized as protective cultures, alternatives to antibiotics, and probiotics for controlling pathogens, mitigating disease, modulating the microbiome, and supporting overall host health. They also support food fermentation and safety, enhance sensory properties, and produce bioactive compounds such as bacteriocins with strong pathogen-inhibitory activity and multifarious health benefits. Despite their advantages in health and agrifood systems, their association with healthcare-associated infections and the spread of antimicrobial resistance raises concerns about their safety. These risks underscore the need for stringent safety evaluations before their use as probiotics, alternatives to antibiotics, or protective cultures. Here, we provide a comprehensive atlas of the multifaceted probiotic and antimicrobial potential, as well as safety considerations of beneficial enterococci. This would provide a valuable resource for future research, regulatory assessments, and applications in the agrifood system and healthcare.

Background: Claims from locals in Nigeria hold that Kunun zaki has some medicinal properties. The study was therefore carried out to investigate the inhibitory effect of lactic acid bacteria (LAB) on multidrug resistant diarrheagenic bacteria in human immunodeficiency virus (HIV) patients. Method: Twenty-five stool samples of seropositive HIV patients from Plateau State Specialist Hospital confirmed to have chronic diarrhea were collected aseptically and bacteria were isolated and identified using microscopic and biochemical techniques. The antibiotics susceptibility tests of the isolates were also carried out using the disc diffusion method to determine drug resistance of the bacteria. The lactic acid bacteria (LAB) used were isolated and identified using standard bacteriological techniques and analytical profile index (API) kits. Diarrheagenic bacteria which showed multiple resistance to antibiotics were tested against lactic acid bacteria using agar well diffusion method. Results: The results showed that Shigella spp (36.0%), Salmonella spp (16.0%) and Escherichia coli (E. coli) (48.0%) were the diarrheagenic bacteria isolated from the HIV patients. The pathogens were most resistant to ampicillin (60%) and least resistant to tarivid (8%). Lactobacillus brevis, Lactobacillus lactis, Lactobacillus casei and Lactobacillus plantarum isolated from Kunun zaki demonstrated antibacterial activity against the pathogens with the effect of the two lactic acid bacteria (L. lactis Gb3ii and L. plantarum Ar1) being significantly higher than the individual LAB used respectively. Conclusion: Lactic acid bacteria from Kunun zaki had demonstrated antibacterial effects against multidrug resistant pathogens, hence could be potential probiotics for inclusion in the fermentation of Kunun zaki that HIV patients could consume.

This study investigates the potential of lactic acid bacteria (LAB) from the Nigerian beverage “kunun zaki” as alternative therapeutic agents against Shigella dysenteriae infections. In light of rising antibiotic resistance, the decline in probiotic usage prompted interest in LAB’s role in countering bacterial dysentery. Shigella dysenteriae, a significant cause of dysentery in developing nations, prompted this research which aims to carry out a preliminary investigation on the therapeutic efficacy and safety of mixed probiotic lactic acid bacteria on albino rats challenged with Shigella dysenteriae. Lactic acid bacteria, known for treating infections, were isolated from the beverage and tested against Shigella dysenteriae. The study employed 15 albino rats for in vivo trials, inducing diarrhea and treating with Lactococcus lactis and Lactobacillus brevis separately (T1 and T2) and combined in a 1 : 1 ratio (T3). Clinical parameters were observed before and after treatment. This revealed that L. lactis and L. brevis administration lowered rectal temperature from an average of 42°C caused by infection to 36.5°C. Stool consistency improved from light brown loose to dark brown semisolid, signifying reduced diarrhea. Bacteriological analysis displayed significant reduction ( ) in Shigella counts in rat intestines across all treatments— to , , and for T1, T2, and T3, respectively. The mixed LAB treatment was notably effective. Lactic acid bacteria counts increased significantly in Shigella-treated rats versus the positive control. Hematology and liver function parameters showed no significant differences between treatments and untreated controls. Lactic acid bacteria from “kunun zaki” exhibited curative potential, individually or combined, against Shigella dysenteriae. These lactic acid bacteria also positively influenced gut microbiota in Shigella-infected albino rats.

This study identified the antimicrobial compounds found in lactic acid bacteria isolated from several traditional fermented foods, such as ogi, ugba, and yoghurt, as well as their antimicrobial effectiveness against a few chosen food pathogens. Fifteen (15) food samples including five each for yoghurt, ogi, and ugba were tested for the presence of lactic acid bacteria. Nine organisms were isolated from the food samples and were phenotypically and genotypically characterized. It was discovered that two of the isolates were Lactococcus spp, five Lactobacillus spp, one Bacillus spp, and one Streptococcus spp. The genotypic characterization revealed that the lactic acid bacteria isolates Lactococcus lactis subsp. lactis 0711XYBLS, Lactobacillus fermentum CS19, Lactococcus lactis and Lactobacillus fermentum were closely related at 99% evolutionary distance. For the sole purpose of this research, Lactococcus lactis subsp. lactis 0711XYBLS and Lactobacillus fermentum CS19 were utilized to determine their antimicrobial potentials against selected food pathogens. Antimicrobial metabolites, diacetyl, hydrogen peroxide and lactic acid were produced by the isolated lactic acid bacteria at varying concentrations. The selected lactic acid bacteria isolates were tested against food pathogens and their clear zones of inhibitions were noted. Lactococcus lactis subsp lactis 0711XYBLS isolated from ogi showed the highest antibacterial activity against Gram positive and Gram negative food pathogens ranging from 18.67 ± 1.15 to 12.67 ± 0.57 and 16.33 ± 0.56 to 8.00 ± 6.08 respectively whereas Lactobacillus fermentum CS19 showed antibacterial activity for Gram positive food pathogens at 16.00 ± 1.00 to 8.67 ± 1.15 and 15.33 ± 1.15 to 8.67 ± 0.57 in Gram negative food pathogens. Between the pathogens, a significant difference was recorded at a significant level of p<0.05. Nevertheless, both organisms demonstrated strong antibacterial activity against the chosen food pathogens and have the potential to be used as new antimicrobial agents. This potential can be used extensively in the food industry as biopresevatives rather than chemical preservation, which may be harmful to consumer’s health.

Probiotic products containing lactic acid bacteria (LAB) are widely promoted for their health benefits, including support for vaginal and gastrointestinal health. However, concerns have emerged regarding the accuracy of product labeling and the viability of the claimed bacterial strains. This study is aimed at evaluating the microbial quality and probiotic potential of three commercial probiotic products marketed for vaginal health. LAB counts were determined, and isolates were identified based on standard microbiological methods. Probiotic properties were evaluated by testing tolerance to acidic pH, bile salts, phenol, and various temperatures, as well as antibacterial activity against selected pathogens. Results showed a significant discrepancy between labeled claim and actual viable counts. Product A retained only 0.96% of its labeled claim; Product B retained 0.12%, while Product C had no viable LAB. Strains isolated from Products A and B included Lactobacillus acidophilus , Lactobacillus plantarum , Lactobacillus rhamnosus , Bifidobacterium lactis , and Bifidobacterium bifidum . These isolates demonstrated varying degrees of acid, bile, and phenol tolerance, and several showed strong antagonistic activity against Staphylococcus aureus , Escherichia coli , and Klebsiella pneumoniae . All isolates were resistant to cloxacillin, ceftriaxone, and ceftazidime but remained sensitive to ciprofloxacin and levofloxacin. The use of CLSI standards, while offering methodological consistency, has limitations for nonclinical strains and should be interpreted cautiously. In conclusion, only two of the three evaluated probiotic products contained viable and functionally relevant LAB strains, raising concerns about quality assurance in commercial probiotics. The results highlight the need for stricter regulatory oversight and routine postmarket validation of probiotic formulations. A limitation of this study is the exclusive use of culture‐based methods, which may not detect nonculturable but viable organisms. Future studies should incorporate molecular techniques for a more comprehensive microbial assessment and to verify the presence of transferable antibiotic resistance genes.