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Abstract：
Clostridioides difficile is the most important pathogen causing antimicrobial-associated diarrhea and has recently been recognized as a cause of community-associated C. difficile infection (CA-CDI). This study aimed to characterize virulence factors, antimicrobial resistance (AMR), ribotype (RT) distribution and genetic relationship of C. difficile isolates from diverse fecally contaminated environmental sources. C. difficile isolates were recovered from different environmental samples in Northern Germany. Antimicrobial susceptibility testing was determined by E-test or disk diffusion method. Toxin genes (tcdA and tcdB), genes coding for binary toxins (cdtAB) and ribotyping were determined by PCR. Furthermore, 166 isolates were subjected to whole genome sequencing (WGS) for core genome multi-locus sequence typing (cgMLST) and extraction of AMR and virulence-encoding genes. Eighty-nine percent (148/166) of isolates were toxigenic, and 51% (76/148) were positive for cdtAB. Eighteen isolates (11%) were non-toxigenic. Thirty distinct RTs were identified. The most common RTs were RT127, RT126, RT001, RT078, and RT014. MLST identified 32 different sequence types (ST). The dominant STs were ST11, followed by ST2, ST3, and ST109. All isolates were susceptible to vancomycin and metronidazole and displayed a variable rate of resistance to moxifloxacin (14%), clarithromycin (26%) and rifampicin (2%). AMR genes, such as gyrA/B, blaCDD-1/2, aph(3\')-llla-sat-4-ant(6)-la cassette, ermB, tet(M), tet(40), and tetA/B(P), conferring resistance toward fluoroquinolone, beta-lactam, aminoglycoside, macrolide and tetracycline antimicrobials, were found in 166, 137, 29, 32, 21, 72, 17, and 9 isolates, respectively. Eleven \"hypervirulent\" RT078 strains were detected, and several isolates belonged to RTs (i.e., RT127, RT126, RT023, RT017, RT001, RT014, RT020, and RT106) associated with CA-CDI, indicating possible transmission between humans and environmental sources pointing out to a zoonotic potential.
摘要：
艰难梭菌是引起抗微生物相关性腹泻的最重要病原体，最近被认为是社区相关艰难梭菌感染（CA-CDI）的原因。本研究旨在表征毒力因子，抗菌素耐药性（AMR），来自不同生殖道污染环境源的艰难梭菌分离株的核糖型（RT）分布和遗传关系。从德国北部的不同环境样品中回收艰难梭菌分离物。通过E-test或圆盘扩散法测定抗菌药物敏感性试验。毒素基因（tcdA和tcdB），通过PCR确定编码二元毒素（cdtAB）和核糖分型的基因。此外，对166个分离株进行了全基因组测序（WGS），以进行核心基因组多位点序列分型（cgMLST），并提取了AMR和毒力编码基因。89%(148/166)的分离株是产毒的，51%(76/148)的cdtAB阳性。18个分离株（11％）是非产毒的。鉴定出30种不同的RT。最常见的RT是RT127、RT126、RT001、RT078和RT014。MLST鉴定了32种不同的序列类型(ST)。主要的STs是ST11,其次是ST2、ST3和ST109。所有分离株对万古霉素和甲硝唑敏感，对莫西沙星的耐药率可变（14％），克拉霉素(26%)和利福平(2%)。AMR基因，如gyrA/B，blaCDD-1/2，aph(3')-llla-sat-4-ant(6)-la盒，ermB,tet(M),tet(40),和tetA/B（P），赋予对氟喹诺酮的耐药性，β-内酰胺，氨基糖苷类,大环内酯类和四环素类抗菌药物,在166、137、29、32、21、72、17和9个分离株中发现，分别。检测到11株“高毒力”RT078株，和几个分离株属于RT(即，RT127、RT126、RT023、RT017、RT001、RT014、RT020和RT106）与CA-CDI关联，表明人类和环境来源之间可能的传播，指出了人畜共患的潜力。
