AUTHOR=Waker Edyta , Ambrozkiewicz Filip , Kulecka Maria , Paziewska Agnieszka , Skubisz Karolina , Cybula Patrycja , Targoński Łukasz , Mikula Michał , Walewski Jan , Ostrowski Jerzy 

TITLE=High Prevalence of Genetically Related Clostridium Difficile Strains at a Single Hemato-Oncology Ward Over 10 Years

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01618

DOI=10.3389/fmicb.2020.01618

ISSN=1664-302X

ABSTRACT=<p><bold>Aims:</bold><italic>Clostridium difficile</italic> (<italic>C. difficile</italic>) infection (CDI) is the main cause of healthcare-associated infectious diarrhea. We used whole-genome sequencing (WGS) to measure the prevalence and genetic variability of <italic>C. difficile</italic> at a single hemato-oncology ward over a 10 year period.</p><p><bold>Methods:</bold> Between 2008 and 2018, 2077 stool samples were obtained from diarrheal patients hospitalized at the Department of Lymphoma; of these, 618 were positive for toxin A/B. 140 isolates were then subjected to WGS on Ion Torrent PGM sequencer.</p><p><bold>Results:</bold> 36 and 104 isolates were recovered from 36 to 46 patients with single and multiple CDIs, respectively. Of these, 131 strains were toxigenic. Toxin gene profiles <italic>tcdA(+);tcdB(+);cdtA/cdtB(+)</italic> and <italic>tcdA(+);tcdB(+);cdtA/cdtB(-)</italic> were identified in 122 and nine strains, respectively. No isolates showed reduced susceptibility to metronidazole and vancomycin. All tested strains were resistant to ciprofloxacin, and 72.9, 42.9, and 72.9% of strains were resistant to erythromycin, clindamycin, or moxifloxacin, respectively. Multi-locus sequence typing (MLST) identified 23 distinct sequence types (STs) and two unidentified strains. Strains ST1 and ST42 represented 31 and 30.1% of all strains tested, respectively. However, while ST1 was detected across nearly all years studied, ST42 was detected only from 2009 to 2011.</p><p><bold>Conclusion:</bold> The high proportion of infected patients in 2008–2011 may be explained by the predominance of more transmissible and virulent <italic>C. difficile</italic> strains. Although this retrospective study was not designed to define outbreaks of <italic>C. difficile</italic>, the finding that most isolates exhibited high levels of genetic relatedness suggests nosocomial acquisition.</p>