Metabolomics analysis identifies intestinal microbiota-derived biomarkers of colonization resistance in clindamycin-treated mice.

BACKGROUND: The intestinal microbiota protect the host against enteric pathogens through a defense mechanism termed colonization resistance. Antibiotics excreted into the intestinal tract may disrupt colonization resistance and alter normal metabolic functions of the microbiota. We used a mouse model to test the hypothesis that alterations in levels of bacterial metabolites in fecal specimens could provide useful biomarkers indicating disrupted or intact colonization resistance after antibiotic treatment. METHODS: To assess in vivo colonization resistance, mice were challenged with oral vancomycin-resistant Enterococcus or Clostridium difficile spores at varying time points after treatment with the lincosamide antibiotic clindamycin. For concurrent groups of antibiotic-treated mice, stool samples were analyzed using quantitative real-time polymerase chain reaction to assess changes in the microbiota and using non-targeted metabolic profiling. To assess whether the findings were applicable to another antibiotic class that suppresses intestinal anaerobes, similar experiments were conducted with piperacillin/tazobactam. RESULTS: Colonization resistance began to recover within 5 days and was intact by 12 days after clindamycin treatment, coinciding with the recovery bacteria from the families Lachnospiraceae and Ruminococcaceae, both part of the phylum Firmicutes. Clindamycin treatment caused marked changes in metabolites present in fecal specimens. Of 484 compounds analyzed, 146 (30%) exhibited a significant increase or decrease in concentration during clindamycin treatment followed by recovery to baseline that coincided with restoration of in vivo colonization resistance. Identified as potential biomarkers of colonization resistance, these compounds included intermediates in carbohydrate or protein metabolism that increased (pentitols, gamma-glutamyl amino acids and inositol metabolites) or decreased (pentoses, dipeptides) with clindamycin treatment. Piperacillin/tazobactam treatment caused similar alterations in the intestinal microbiota and fecal metabolites. CONCLUSIONS: Recovery of colonization resistance after antibiotic treatment coincided with restoration of several fecal bacterial metabolites. These metabolites could provide useful biomarkers indicating intact or disrupted colonization resistance during and after antibiotic treatment.

Novel strategies for enhanced removal of persistent Bacillus anthracis surrogates and Clostridium difficile spores from skin.

BACKGROUND: Removing spores of Clostridium difficile and Bacillus anthracis from skin is challenging because they are resistant to commonly used antimicrobials and soap and water washing provides only modest efficacy. We hypothesized that hygiene interventions incorporating a sporicidal electrochemically generated hypochlorous acid solution (Vashe(®)) would reduce the burden of spores on skin. METHODS: Hands of volunteers were inoculated with non-toxigenic C. difficile spores or B. anthracis spore surrogates to assess the effectiveness of Vashe solution for reducing spores on skin. Reduction in spores was compared for Vashe hygiene interventions versus soap and water (control). To determine the effectiveness of Vashe solution for removal of C. difficile spores from the skin of patients with C. difficile infection (CDI), reductions in levels of spores on skin were compared for soap and water versus Vashe bed baths. RESULTS: Spore removal from hands was enhanced with Vashe soak (>2.5 log10 reduction) versus soap and water wash or soak (~2.0 log10 reduction; P<0.05) and Vashe wipes versus alcohol wipes (P<0.01). A combined approach of soap and water wash followed by soaking in Vashe removed >3.5 log10 spores from hands (P<0.01 compared to washing or soaking alone). Bed baths using soap and water (N =26 patients) did not reduce the percentage of positive skin cultures for CDI patients (64% before versus 57% after bathing; P =0.5), whereas bathing with Vashe solution (N =21 patients) significantly reduced skin contamination (54% before versus 8% after bathing; P =0.0001). Vashe was well-tolerated with no evidence of adverse effects on skin. CONCLUSIONS: Vashe was safe and effective for reducing the burden of B. anthracis surrogates and C. difficile spores on hands. Bed baths with Vashe were effective for reducing C. difficile on skin. These findings suggest a novel strategy to reduce the burden of spores on skin.

Evaluation of a hand-held far-ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens.

BACKGROUND: Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe and rapid. The Sterilray™ Disinfection Wand device is a hand-held room decontamination technology that utilizes far-ultraviolet radiation (185-230 nm) to kill pathogens. METHODS: We examined the efficacy of disinfection using the Sterilray device in the laboratory, in rooms of hospitalized patients, and on surfaces outside of patient rooms (i.e. keyboards and portable medical equipment). Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly-touched surfaces before and after use of the Sterilray device. RESULTS: On inoculated surfaces in the laboratory, application of the Sterilray device at a radiant dose of 100 mJ/cm(2) for ~ 5 seconds consistently reduced recovery of C. difficile spores by 4.4 CFU log10, MRSA by 5.4 log(10)CFU and of VRE by 6.9 log10CFU. A >3 log10 reduction of MRSA and VRE was achieved in ~2 seconds at a lower radiant dose, but killing of C. difficile spores was significantly reduced. On keyboards and portable medical equipment that were inoculated with C. difficile spores, application of the Sterilray device at a radiant dose of 100 mJ/cm(2) for ~ 5 seconds reduced contamination by 3.2 log10CFU. However, the presence of organic material reduced the lethal effect of the far-UV radiation. In hospital rooms that were not pre-cleaned, disinfection with the Sterilray device significantly reduced the frequency of positive C. difficile and MRSA cultures (P =0.007). CONCLUSIONS: The Sterilray™ Disinfection Wand is a novel environmental disinfection technology that rapidly kills C. difficile spores and other healthcare-associated pathogens on surfaces. However, the presence of organic matter reduces the efficacy of far-UV radiation, possibly explaining the more modest results observed on surfaces in hospital rooms that were not pre-cleaned.