Listeriosis is a severe food borne disease with a mortality rate of up to 30% caused by pathogenic Listeria monocytogenes via the production of several virulence factors including listeriolysin O (LLO), transcriptional activator (PrfA), actin (Act), internalin (Int), etc. It is a foodborne disease predominantly causing infections through consumption of contaminated food and is often associated with ready-to-eat food (RTE) and dairy products. Common medication for listeriosis such as antibiotics might cause an eagle effect and antibiotic resistance if it is overused. Therefore, exploration of the use of lactic acid bacteria (LAB) with probiotic characteristics and multiple antimicrobial properties is increasingly getting attention for their capability to treat listeriosis, vaccine development, and hurdle technologies. The antilisterial gene, a gene coding to produce antimicrobial peptide (AMP), one of the inhibitory substances found in LAB, is one of the potential key factors in listeriosis treatment, coupled with the vast array of functions and strategies; this review summarizes the various strategies by LAB against L. monocytogenes and the prospect in development of a ‘generally regarded as safe’ LAB for treatment of listeriosis.

A total of 20 of isolates of lactic acid bacteria (LAB) were selected and screened for antagonistic activity against clinical strains of 30 clinical isolates of extremely drug-resistant (XDR) Acinetobacter baumannii using the well diffusion assay method. Results showed that 50% of the highly LAB strains possessed inhibitory activity against (up to 66%) of the XDR A. baumannii strains tested. The supernatant of the twenty LAB strains was subjected to gas chromatography mass spectrometry (GCMS) revealed that the common compound found in the active isolates against XDR A. baumannii was 3-Isobutyl-2,3,6,7,8,8a-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione, a known potential diketopiperazine group. The molecular docking study against potential antibacterial targets with selected ligands was performed to predict the binding mode of interactions, which is responsible for antibacterial activity. The docking analysis of the potent compounds supported the potential antibacterial activity exhibiting high inhibition constant and binding affinity in silico.

Ticks harbour diverse microbial communities, but opportunistic and environmentally associated bacteria within these systems remain poorly understood. During attempts to establish primary cell cultures from surface-sterilized embryos of the dog tick Rhipicephalus linnaei , we detected the presence of Stenotrophomonas maltophilia , a multidrug-resistant environmental bacterium and emerging opportunistic pathogen. Microscopic examination of Giemsa-stained smears showed abundant extracellular rod-shaped bacteria closely associated with degenerating tick cells, with no evidence of intracellular infection. Molecular identification based on 16S and 23S rRNA gene sequencing confirmed the bacteria as S. maltophilia , and antibiotic susceptibility testing revealed resistance to amoxicillin-clavulanic acid, imipenem, cefoxitin, and nitrofurantoin, but susceptibility to meropenem. Multi-locus sequence typing (MLST) identified the isolate as sequence type 948 (ST948), which is a single-locus variant of ST408 and a double-locus variant of ST144, both of which are representatives of environmental and clinical S. maltophilia strains from diverse geographic origins. These findings provide the first evidence of S. maltophilia occurring in a tick-derived cell culture system and highlight the need to consider opportunistic bacteria when interpreting tick microbiome and cell culture-based studies, particularly those involving veterinary-relevant tick species.