Tasnuva Rashid

Shoe soles as a potential vector for pathogen transmission: A systematic review

Shoe soles are possible vectors for infectious diseases. Although studies have been performed to assess the prevalence of infectious pathogens on shoe soles and decontamination techniques, no systematic review has ever occurred. The aim of this study was to perform a systematic review of the literature to determine the prevalence of infectious agents on shoe bottoms and possible decontamination strategies. Three electronic bibliographic databases were searched using a predefined search strategy evaluating prevalence of infectious pathogens on shoe bottoms and decontamination strategies. Quality assessment was performed independently by two reviews with disagreements resolved by consensus. Thirteen studies were identified that supported the hypothesis that shoe soles are a vector for infectious pathogens. Methicillin‐resistant Staphylococcus aureus, Clostridium difficile and multidrug‐resistant Gram‐negative species among other pathogens were documented on shoe bottoms in the health care setting, in the community and among food workers. Fifteen studies were identified that investigated decontamination strategies for shoe soles. A number of decontamination strategies have been studied of which none have been shown to be consistently successful at disinfecting shoe soles. In conclusion, a high prevalence of microbiological pathogens was identified from shoe soles studied in the health care, community and animal worker setting. An effective decontamination strategy for shoe soles was not identified. Studies are needed to assess the potential for contaminated shoes to contribute to the transmission of infectious pathogens.

First Environmental Investigation of Toxigenic Clostridium difficile at a Large Hospital in Bangladesh

Abstract Background Toxigenic Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients in the developed world and an emerging pathogen in developing countries due to increased use of broad-spectrum antibiotics. Although likely ubiquitous worldwide, the prevalence of toxigenic C. difficile spores in the hospital environs of developing countries is poorly understood. The objectives of the study are to isolate and characterize C. difficile from the hospital environs of a large hospitals in Dhaka, Bangladesh. Methods As part of our environmental surveillance effort, we collected 330 shoe-bottom swab samples from hospital employees, patients, and visitors inside of a large hospital in Dhaka, Bangladesh. Samples were analyzed for C. difficile using anaerobic enrichment culture and molecular methods. Suspected colonies from cycloserine cefoxitin fructose agar (CCFA) plates were identified by PCR (tcdA, tcdB, cdtA, cdtB and tpi genes) and strain typed using fluorescent PCR ribotyping, and MLVA methods. Results A total 149 of 333 (44.7%) shoe-bottom swab samples were culture positive for C. difficile of which 19.8% samples were toxigenic (tcdA and tcdB) C. difficile. A total of 11 distinct ribotypes were identified from 58 toxigenic C. difficile isolates tested. Predominant ribotypes were F053-163 (24.1%), F017 (20.7%), F106 (19.0%), F014-020 (17.2%). Other ribotypes were R001, F005, F010, F018, F054, F216, and FP407. No R027 and R078 C. difficile isolated. A broad MLVA diversity has been seen among the tested strains. Conclusion We identified a high prevalence of toxigenic C. difficile with diverse ribotypes from hospital environmental shoe-bottom swabs in Bangladesh. This is the first hospital environmental report of C. difficile from Bangladesh. Disclosures All authors: No reported disclosures.

A Protocol to Characterize the Morphological Changes of Clostridium difficile in Response to Antibiotic Treatment

Assessment of antibiotic action with new drug development directed towards anaerobic bacteria is difficult and technically demanding. To gain insight into possible MOA, morphologic changes associated with antibiotic exposure can be visualized using scanning electron microscopy (SEM). Integrating SEM imaging with traditional kill curves may improve our insight into drug action and advance the drug development process. To test this premise, kill curves and SEM studies were conducted using drugs with known but different MOA (vancomycin and metronidazole). C. difficile cells (R20291) were grown with or without the presence of antibiotic for up to 48 h. Throughout the 48 h interval, cells were collected at multiple time points to determine antibiotic efficacy and for imaging on the SEM. Consistent with previous reports, vancomycin and metronidazole had significant bactericidal activity following 24 h of treatment as measured by colony-forming unit (CFU) counting. Using SEM imaging we determined that metronidazole had significant effects on cell length (> 50% reduction in cell length for each antibiotic; P< 0.05) compared to controls and vancomycin. While the phenotypic response to drug treatment has not been documented previously in this manner, they are consistent with the drugs MOA demonstrating the versatility and reliability of the imaging and measurements and the application of this technique for other experimental compounds.