Inhibition of methicillin-resistant Staphylococcus aureus by an in vitro continuous-flow culture containing human stool microflora.

Research Section, Louis Stokes Cleveland Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA.
FEMS Microbiology Letters (Impact Factor: 2.72). 01/2005; 241(2):201-5. DOI: 10.1016/j.femsle.2004.10.021
Source: PubMed

ABSTRACT We used an in vitro continuous-flow culture model of human stool microflora to examine the ability of human stool microflora to inhibit growth of two methicillin-resistant S. aureus (MRSA) strains. Continuous-flow cultures consistently eliminated MRSA inocula of 10(6) cfu/mL within 4 days, and addition of continuous-flow culture resulted in elimination of a pre-established MRSA culture ( approximately 10(8) cfu/mL) within 6-8 days. Anaerobic or "aerobic" (i.e., continuous bubbling of room air to eliminate obligate anaerobes) cultures eliminated MRSA at similar rates. The MRSA strains were unable to replicate under anaerobic conditions in sterile filtrates produced from the continuous-flow culture, but rapid growth occurred when glucose was added. These data demonstrate that indigenous stool microflora efficiently eliminate MRSA colonization and obligate anaerobes are not essential for inhibition. Our findings also suggest that inhibition of MRSA in continuous-flow cultures is due to depletion of nutrients rather than production of inhibitory conditions.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mucosal surfaces such as the gut, vagina and oral cavity are colonized by microbiota that are an integral component of the healthy ecosystem. Recent molecular techniques make it feasible to correlate antimicrobial dosing levels with changes in microbiome composition. The objective of this study was to characterize the rat oral plaque microbiome composition at doses of ciprofloxacin that were considerably above and below nominal in vitro minimal inhibitory concentrations (MICs) of a variety of gram positive oral commensal bacteria. We exposed the oral cavities of rats to relatively low (0.1 μg/mL) and high (20 μg/mL) doses of ciprofloxacin in the drinking water over a 3 day period. Plaque microbiota were characterized using 454 pyrosequencing. The rat indigenous community was dominated by Rothia (74.4 %) and Streptococcus genera (4.7%). Dosing at 0.1 μg/mL was associated with changes in Rothia and Streptococcus genera which were not significant, while dosing at 20 μg/mL caused pronounced (significant) reduction in the relative abundance of the Streptococcus genus. Taxonomic independent analysis indicated that the perturbation in the overall community structure attributed to dosing with ciprofloxacin at either the low or high dose was relatively low. The results suggest that it is feasible to use an antimicrobial dosing regime to selectively target a specific subset of a mucosal microbiome for elimination with minimal perturbation of the entire community.
    Molecular Oral Microbiology 07/2013; · 2.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Meticillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant micro-organism and is the principal nosocomial pathogen worldwide. Following initial in vitro experiments demonstrating that Lactobacillus acidophilus CL1285(®) and Lactobacillus casei LBC80R(®) commercial strains exhibit antibacterial activity against clinical MRSA isolates, we conducted a literature search to find any evidence of probiotic efficacy in decolonisation or treatment of S. aureus infection. As summarised below, many strains of lactobacilli and bifidobacteria isolated from a variety of sources inhibited the growth of S. aureus and clinical isolates of MRSA in vitro. The most active strains were Lactobacillus reuteri, Lactobacillus rhamnosus GG, Propionibacterium freudenreichii, Propionibacterium acnes, Lactobacillus paracasei, L. acidophilus, L. casei, Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus fermentum and Lactococcus lactis. Their effects were mediated both by direct cell competitive exclusion as well as production of acids or bacteriocin-like inhibitors. L. acidophilus also inhibited S. aureus biofilm formation and lipase production. In vitro antimicrobial activity did not necessarily assure efficacy in vivo in animal infectious models, e.g. S. aureus 8325-4 was most sensitive in vitro to L. acidophilus, whilst in vivo Bifidobacterium bifidum best inhibited experimental intravaginal staphylococcosis in mice. On the other hand, L. plantarum, which showed the highest inhibition activity against S. aureus in vitro, was also very effective topically in preventing skin wound infection with S. aureus in mice. Very few clinical data were found on the interactions between probiotics and MRSA, but the few identified clinical cases pointed to the feasibility of elimination or reduction of MRSA colonisation with probiotic use.
    International journal of antimicrobial agents 09/2013; · 3.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Effect of apidaecin on common carp (Cyprinus carpio) based on growth performance, feed utilization (Feed Conversion Ratio, FCR) and immune parameters were investigated. Twelve aquaria with three replicates for G1-3 and control were used. The synthesized apidaecin peptide was added to common carp basal diets (Control) as additives in three concentrations: 10.0 mg kg− 1 (G1), 15.0 mg kg− 1 (G2) and 30.0 mg kg− 1 (G3) by wet weight of basal diet. After an 80-day feeding experiment, G2 and G3 showed significantly better (P < 0.05) results of growth performances and FCR than the control. However, there was no remarkable difference (P > 0.05) between G2 and G3. As for G1, the final weight, SGR (Specific Growth Rate) and DG (Daily Gain) were increased and the FCR was decreased, but not significantly (P > 0.05) compared with the control. The serum lysozyme activity of G2 and G3 was significantly increased (P < 0.05) than the control. As for the alternative complement pathway activity, G2 and G3 were also higher (P < 0.05) than the control. However, no significant difference (P > 0.05) was found whichever between G2 and G3 or between G1 and G2 in both lysozyme and the alternative complement pathway activities. Furthermore, there was no remarkable difference between G1 and the control in immune parameters.
    Aquaculture 07/2008; · 1.83 Impact Factor

Full-text (2 Sources)

1 Download
Available from
Jan 7, 2015