title: Sensitive and selective culture medium for detection of environmental Clostridium difficile isolates without requirement for anaerobic culture conditions.
abstract: Effective and easy-to-use methods for detecting Clostridium difficile spore contamination would be useful for identifying environmental reservoirs and monitoring the effectiveness of room disinfection. Culture-based detection methods are sensitive for detecting C. difficile, but their utility is limited due to the requirement of anaerobic culture conditions and microbiological expertise. We developed a low-cost selective broth medium containing thioglycolic acid and l-cystine, termed C. difficile brucella broth with thioglycolic acid and l-cystine (CDBB-TC), for the detection of C. difficile from environmental specimens under aerobic culture conditions. The sensitivity and specificity of CDBB-TC (under aerobic culture conditions) were compared to those of CDBB (under anaerobic culture conditions) for the recovery of C. difficile from swabs collected from hospital room surfaces. CDBB-TC was significantly more sensitive than CDBB for recovering environmental C. difficile (36/41 [88%] versus 21/41 [51%], respectively; P = 0.006). C. difficile latex agglutination, an enzyme immunoassay for toxins A and B or glutamate dehydrogenase, and a PCR for toxin B genes were all effective as confirmatory tests. For 477 total environmental cultures, the specificity of CDBB-TC versus that of CDBB based upon false-positive yellow-color development of the medium without recovery of C. difficile was 100% (0 false-positive results) versus 96% (18 false-positive results), respectively. False-positive cultures for CDBB were attributable to the growth of anaerobic non-C. difficile organisms that did not grow in CDBB-TC. Our results suggest that CDBB-TC provides a sensitive and selective medium for the recovery of C. difficile organisms from environmental samples, without the need for anaerobic culture conditions.
authors: Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
authors: Jennifer L
authors: JL
authors: Cadnum
authors: Research Service, Cleveland VA Medical Center, Cleveland, Ohio, USA.
authors: Kelly N
authors: KN
authors: Hurless
authors: Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
authors: Abhishek
authors: A
authors: Deshpande
authors: Research Service, Cleveland VA Medical Center, Cleveland, Ohio, USA.
authors: Michelle M
authors: MM
authors: Nerandzic
authors: Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
authors: Sirisha
authors: S
authors: Kundrapu
authors: Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA Geriatric Research, Education, and Clinical Center, Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA curtisd123@yahoo.com.
authors: Curtis J
authors: CJ
authors: Donskey
mesh_terms: D000332:Aerobiosis; D016360:Clostridioides difficile / Q000254:growth & development* / Q000302:isolation & purification*; D003116:Color; D003470:Culture Media / Q000737:chemistry* / Q000191:economics; D003545:Cysteine / Q000378:metabolism; D003951:Diagnostic Errors; D004783:Environmental Microbiology; D006801:Humans; D012641:Selection, Genetic; D012680:Sensitivity and Specificity; D013864:Thioglycolates / Q000378:metabolism
chemical_list: D003470:Culture Media; D013864:Thioglycolates; C017487:2-mercaptoacetate; D003545:Cysteine