Stewart David B, Berg Arthur S, Hegarty John P
Departments of *Surgery †Public Health Sciences and Statistics, The Pennsylvania State University College of Medicine, Hershey, PA.
Ann Surg. 2014 Aug;260(2):299-304. doi: 10.1097/SLA.0000000000000469.
To identify Clostridium difficile genotypes, which are associated with recurrent C difficile infection (RCDI).
Reliable bacterial genetic factors predicting RCDI are currently lacking.
Inpatients and outpatients 18 years or older treated at our institution for C difficile infection (CDI) of any severity were consecutively enrolled. CDI was defined as symptoms of colitis with a positive PCR stool test. Each bacterial isolate was studied for virulence factors: tcdC mutations, including single nucleotide polymorphisms (SNPs) via PCR, the presence of genes for toxins A, B and binary toxin using restriction fragment length polymorphism, and identification of ribotype by PCR. χ tests, t tests, and logistic and linear regression were used to determine which virulence factors predicted RCDI and the need for hospital admission, with corrections made for multiple statistical comparisons.
Seventy-three patients (male: 52%; mean age: 66 ± 15 years) were studied. Binary toxin gene (P = 0.03) was associated with at least 1 episode of RCDI, as was the presence of SNPs C184T (P = 0.006) and A117T (P = 0.003). The presence of the binary toxin gene with either of these tcdC SNPs increased RCDI by 80% (P = 0.0002) but did not predict the need for hospital admission. None of the other virulence factors, including ribotype 027, were predictive of RCDI.
The presence of the binary toxin gene and tcdC SNPs C184T and A117T strongly predict RCDI. The presence of both tcdC SNPs and the binary toxin gene significantly increased the risk of RCDI, which might warrant longer antibiotic courses to eradicate the infection.
鉴定与艰难梭菌反复感染（RCDI）相关的艰难梭菌基因型。
目前缺乏预测RCDI的可靠细菌遗传因素。
连续纳入在我们机构接受治疗的18岁及以上因任何严重程度的艰难梭菌感染（CDI）的住院和门诊患者。CDI定义为具有PCR粪便检测阳性的结肠炎症状。对每个细菌分离株进行毒力因子研究：通过PCR检测tcdC突变，包括单核苷酸多态性（SNP），使用限制性片段长度多态性检测毒素A、B和二元毒素基因的存在，并通过PCR鉴定核糖体分型。采用χ检验、t检验、逻辑回归和线性回归来确定哪些毒力因子可预测RCDI以及住院需求，并对多重统计比较进行校正。
研究了73例患者（男性：52%；平均年龄：66±15岁）。二元毒素基因（P = 0.03）与至少1次RCDI发作相关，SNP C184T（P = 0.006）和A117T（P = 0.003）的存在也与之相关。二元毒素基因与这些tcdC SNP中的任何一个同时存在会使RCDI增加80%（P = 0.0002），但不能预测住院需求。其他毒力因子，包括核糖体分型027，均不能预测RCDI。
二元毒素基因以及tcdC SNP C184T和A117T的存在强烈预测RCDI。tcdC SNP和二元毒素基因同时存在显著增加了RCDI的风险，这可能需要更长疗程的抗生素来根除感染。
