Daniel R Knight1, Steven Giglio2, Peter G Huntington3, Tony M Korman4, Despina Kotsanas4, Casey V Moore5, David L Paterson6, Louise Prendergast7, Charlotte A Huber6, Jennifer Robson8, Lynette Waring7, Michael C Wehrhahn9, Gerhard F Weldhagen5, Richard M Wilson2, Thomas V Riley10. 1. Microbiology and Immunology, School of Pathology and Laboratory Medicine, The University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Western Australia, Australia. 2. Healthscope Pathology, Microbiology Department, Wayville, South Australia, Australia. 3. Department of Microbiology, Pathology North, Royal North Shore Hospital, St Leonards, New South Wales, Australia. 4. Monash Infectious Diseases, Monash Health, Monash University, Clayton, Victoria, Australia. 5. Microbiology and Infectious Diseases Laboratories, SA Pathology, Adelaide, South Australia, Australia. 6. University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia. 7. Melbourne Pathology, Collingwood, Victoria, Australia. 8. Sullivan Nicolaides Pathology, Taringa, Queensland, Australia. 9. Douglass Hanly Moir Pathology, Macquarie Park, New South Wales, Australia. 10. Microbiology and Immunology, School of Pathology and Laboratory Medicine, The University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Western Australia, Australia Department of Microbiology, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, Western Australia, Australia thomas.riley@uwa.edu.au.
Abstract
OBJECTIVES: The objective of this study was to determine the activity of fidaxomicin and comparator antimicrobials against Clostridium difficile isolated from patients with C. difficile infection (CDI) in Australian hospitals and in the community. METHODS: One private and one public laboratory from five states in Australia submitted a total of 474 isolates/PCR-positive stool samples during three collection periods in August-September 2013 (n = 175), February-March 2014 (n = 134) and August-September 2014 (n = 165). Isolate identification was confirmed by selective culture for C. difficile and a proportion of isolates from each state were characterized by PCR for toxin genes and PCR ribotyping. MICs of fidaxomicin and eight comparator antimicrobials were determined for all isolates using agar methodology. RESULTS: Site collection yielded 440 isolates of C. difficile and PCR revealed a heterogeneous strain population comprising 37 different PCR ribotypes (RTs), 95% of which were positive for tcdA and tcdB (A+B+). The most common RTs were 014 (29.8%) and 002 (15.9%). Epidemic RT 027 was not identified; however, small numbers of virulent RTs 078 and 244 were found. Resistance to vancomycin, metronidazole and fidaxomicin was not detected and resistance to moxifloxacin was very low (3.4%). Fidaxomicin showed potent in vitro activity against all 440 isolates (MIC50/MIC90 0.03/0.12 mg/L) and was superior to metronidazole (MIC50/MIC90 0.25/0.5 mg/L) and vancomycin (MIC50/MIC90 1/2 mg/L). CONCLUSIONS: These data confirm the potent in vitro activity of fidaxomicin against C. difficile. Moreover, this study provides an important baseline for ongoing long-term surveillance of antimicrobial resistance and prospective tracking of prominent and emerging strain types.
OBJECTIVES: The objective of this study was to determine the activity of fidaxomicin and comparator antimicrobials against Clostridium difficile isolated from patients with C. difficileinfection (CDI) in Australian hospitals and in the community. METHODS: One private and one public laboratory from five states in Australia submitted a total of 474 isolates/PCR-positive stool samples during three collection periods in August-September 2013 (n = 175), February-March 2014 (n = 134) and August-September 2014 (n = 165). Isolate identification was confirmed by selective culture for C. difficile and a proportion of isolates from each state were characterized by PCR for toxin genes and PCR ribotyping. MICs of fidaxomicin and eight comparator antimicrobials were determined for all isolates using agar methodology. RESULTS: Site collection yielded 440 isolates of C. difficile and PCR revealed a heterogeneous strain population comprising 37 different PCR ribotypes (RTs), 95% of which were positive for tcdA and tcdB (A+B+). The most common RTs were 014 (29.8%) and 002 (15.9%). Epidemic RT 027 was not identified; however, small numbers of virulent RTs 078 and 244 were found. Resistance to vancomycin, metronidazole and fidaxomicin was not detected and resistance to moxifloxacin was very low (3.4%). Fidaxomicin showed potent in vitro activity against all 440 isolates (MIC50/MIC90 0.03/0.12 mg/L) and was superior to metronidazole (MIC50/MIC90 0.25/0.5 mg/L) and vancomycin (MIC50/MIC90 1/2 mg/L). CONCLUSIONS: These data confirm the potent in vitro activity of fidaxomicin against C. difficile. Moreover, this study provides an important baseline for ongoing long-term surveillance of antimicrobial resistance and prospective tracking of prominent and emerging strain types.
Authors: Grace O Androga; Julie Hart; Niki F Foster; Adrian Charles; David Forbes; Thomas V Riley Journal: J Clin Microbiol Date: 2015-09-09 Impact factor: 5.948
Authors: C M Thorpe; L A McDermott; M K Tran; J Chang; S G Jenkins; E J C Goldstein; R Patel; B A Forbes; S Johnson; D N Gerding; D R Snydman Journal: Antimicrob Agents Chemother Date: 2019-06-24 Impact factor: 5.191
Authors: Stacey Hong; Papanin Putsathit; Narelle George; Christine Hemphill; Peter G Huntington; Tony M Korman; Despina Kotsanas; Monica Lahra; Rodney McDougall; Casey V Moore; Graeme R Nimmo; Louise Prendergast; Jennifer Robson; Lynette Waring; Michael C Wehrhahn; Gerhard F Weldhagen; Richard M Wilson; Thomas V Riley; Daniel R Knight Journal: J Clin Microbiol Date: 2020-10-21 Impact factor: 5.948