Lactobacillus rhamnosus and Staphylococcus epidermidis in gut microbiota: in vitro antimicrobial resistance

Abstract

The gastrointestinal tract is one of the most complex microbiological niches containing beneficial and non-pathogenic bacterial strains of which some may evolve into virulent under specific conditions. Lactobacillus rhamnosus GG is of the most known beneficial species with an ability to protect the intestine as opposed to Staphylococcus epidermidis 444 which causes serious health risks due to its high antimicrobial resistance. This study investigates first the survival and coexistence ability of L. rhamnosus GG, and S. epidermidis 444 at different pH levels. Subsequently, lysozyme's antimicrobial and antibiofilm effect on these two strains was elucidated before adding different concentrations of oxytetracycline hydrochloride antibiotic. Results showed that 50% inhibition of L. rhamnosus GG, S. epidermidis 444, and a co-culture of these planktonic strains were obtained respectively at a lysozyme concentration of 30, 18, and 26 mg/mL after the addition of ethylenediamine tetra-acetic acid (EDTA). At a pH of 7.5, mixing lysozyme (at IC50) and EDTA with oxytetracycline hydrochloride (700 μg/mL) showed an additional bactericidal effect as compared to its known bacteriostatic effect. Similarly, the addition of lysozyme to the antibiotic further increased the biofilm eradication of S. epidermidis 444 and L. rhamnosus GG where a maximal eradication of 70% was reached. Therefore, the potential development of new drugs based on adding a lysozyme-EDTA mixture to different types of antibiotics may be highly promising.

Regulation of the growth performance and the gastrointestinal microbiota community by the addition of defective pear fermentation to feed of small-tailed Han sheep

“…Group C exhibited the highest relative abundance of Proteobacteria but the lowest of Bacteroidota among all groups (Pitta et al, 2014 ). Previous research suggests that Bacteroidota are more efficient in degrading carbohydrates and polysaccharides than Proteobacteria , which could explain the reduced digestion and absorption capabilities, and consequently poorer growth performance, in group C. Additionally, the presence of Staphylococcus , of which more than half are pathogenic, was noted in group C (Hindieh et al, 2022 ). In contrast, only minimal amounts of Staphylococcus were detected in the DPF-supplemented groups, indicating that DPF addition to the diet of small-tailed Han sheep could effectively reduce Staphylococcus levels in the jejunum ( Figure 3F ; Table 7 ).…”

Prevention and treatment of cancers by tumor antigen-expressing Staphylococcus epidermidis

“…The authors convincingly report the total absence of local inflammation in the skin from mice gently swabbed with different S. epidermidis strains. That said, there are multiple reports suggesting that S. epidermidis can be found in the gut microbiota 8 , 9 . Hence, in a hypothetical, yet plausible scenario, the presence of antigen-expressing S. epidermidis strains in the skin could lead to the contamination of other, non-skin microbiotas (such as the oral and nasal cavities and other downstream segments of the intestinal or respiratory tracts, respectively) by such strains, then causing local pro-inflammatory perturbations that are not detectable at the surface of the body, yet elicit systemic antimicrobial immune responses that participate to immunosurveillance ( Figure 1 ).…”