Biocide Resistance and Transmission of Clostridium difficile Spores Spiked onto Clinical Surfaces from an American Health Care Facility

ABSTRACT Clostridium difficile is the primary cause of antibiotic-associated diarrhea globally. In unfavorable environments, the organism produces highly resistant spores which can survive microbicidal insult. Our previous research determined the ability of C. difficile spores to adhere to clinical surfaces, finding that spores had markedly different hydrophobic properties and adherence abilities. Investigation into the effect of the microbicide sodium dichloroisocyanurate on C. difficile spore transmission revealed that sublethal concentrations increased spore adherence without reducing viability. The present study examined the ability of spores to transmit across clinical surfaces and their response to an in-use disinfection concentration of 1,000 ppm of chlorine-releasing agent sodium dichloroisocyanurate. In an effort to understand if these surfaces contribute to nosocomial spore transmission, surgical isolation gowns, hospital-grade stainless steel, and floor vinyl were spiked with 1 × 106 spores/ml of two types of C. difficile spore preparations: crude spores and purified spores. The hydrophobicity of each spore type versus clinical surface was examined via plate transfer assay and scanning electron microscopy. The experiment was repeated, and spiked clinical surfaces were exposed to 1,000 ppm sodium dichloroisocyanurate at the recommended 10-min contact time. Results revealed that the hydrophobicity and structure of clinical surfaces can influence spore transmission and that outer spore surface structures may play a part in spore adhesion. Spores remained viable on clinical surfaces after microbicide exposure at the recommended disinfection concentration, demonstrating ineffectual sporicidal action. This study showed that C. difficile spores can transmit and survive between various clinical surfaces despite appropriate use of microbicides. IMPORTANCE Clostridium difficile is a health care-acquired organism and the causative agent of antibiotic-associated diarrhea. Its spores are implicated in fecal to oral transmission from contaminated surfaces in the health care environment due to their adherent nature. Contaminated surfaces are cleaned using high-strength chemicals to remove and kill the spores; however, despite appropriate infection control measures, there is still high incidence of C. difficile infection in patients in the United States. Our research examined the effect of a high-strength biocide on spores of C. difficile which had been spiked onto a range of clinically relevant surfaces, including isolation gowns, stainless steel, and floor vinyl. This study found that C. difficile spores were able to survive exposure to appropriate concentrations of biocide, highlighting the need to examine the effectiveness of infection control measures to prevent spore transmission and to consider the prevalence of biocide resistance when decontaminating health care surfaces.

Psychoactive plant- and mushroom-associated alkaloids from two behavior modifying cicada pathogens

Entomopathogenic fungi routinely kill their hosts before releasing infectious spores, but select species keep insects alive while sporulating, which enhances dispersal. Transcriptomics and metabolomics studies of entomopathogens with post-mortem dissemination from their parasitized hosts have unraveled infection processes and host responses, yet mechanisms underlying active spore transmission by Entomophthoralean fungi in living insects remain elusive. Here we report the discovery, through metabolomics, of the plant-associated amphetamine, cathinone, in four Massospora cicadina-infected periodical cicada populations, and the mushroom-associated tryptamine, psilocybin, in annual cicadas infected with Massospora platypediae or Massospora levispora, which appear to represent a single fungal species. The absence of some fungal enzymes necessary for cathinone and psilocybin biosynthesis along with the inability to detect intermediate metabolites or gene orthologs are consistent with possibly novel biosynthesis pathways in Massospora. The neurogenic activities of these compounds suggest the extended phenotype of Massospora that modifies cicada behavior to maximize dissemination is chemically-induced.