Study of the frequency of Clostridium difficile tcdA, tcdB, cdtA and cdtB genes in feces of Calves in south west of Iran

Abstract

BackgroundClostridium difficile (C. difficile) is a gram-positive, toxin-producing bacillus which is an intestinal pathogen in both humans and animals and causes a range of digestive disorders including inflammation of the bowel, abdominal pain, fever and diarrhea. C. difficile toxins include enterotoxin (Toxin A), cytotoxin (Toxin B) and a binary toxin. Two large protein toxins A and B are encoded by separate genes, tcdA and tcdB. Clostridium difficile infection (CDI) mainly caused by the activity of the genes tcdA and tcdB. The binary toxin is encoded by the genes cdtA and cdtB. The binary toxin caused increased adherence of bacteria to intestinal epithelium. The aim of the present study was isolation of C. difficile from feces of calves, and study of the frequency of C. difficile virulence genes.Methods150 samples of fresh feces from calves were collected and C. difficile was isolated from feces of calves using bacterial culture methods. DNA was extracted by a genomic DNA purification kit. Then PCR method was used for definitive diagnosis of C. difficile. Multiplex PCR method performed for identification of tcdA, tcdB, cdtA and cdtB genes. In the final stage antimicrobial resistance determining was carried out by standard Bauer-Kirby disk diffusion method.ResultsC. difficile was isolated from 90 samples (60%). The tcdA was observed in 8 isolates (8.8%), tcdB in 16 isolates (17.7%), cdtA in 8 isolates (8.8%) and cdtB in 14 isolates (15.5%). Only 1 isolated (1.1%) was containing all four genes tcdA, tcdB, cdtA and cdtB, 2 isolates (2.2%) only had both tcdA and tcdB genes, and there was no sample positive only for both cdtA and cdtB. The highest rate of drug resistance was against clindamycin (100%) and the highest rate of drug sensitivity was against ciprofloxacin (50%).ConclusionThe results showed high incidence of C. difficile and also high antibiotic resistance of this bacterium, but frequency of strains containing virulence genes (tcdA, tcdB, cdtA and cdtB) was low.

Prevalence and molecular types of Clostridium difficile isolates from faecal specimens of patients in a tertiary care centre

“…During a hospital outbreak of CDI in Pittsburgh, USA, up to 65 % of the clinically recovered C. difficile isolates had binary toxin genes (McEllistrem et al, 2005). Doosti & Mokhtari-Farsani (2014) reported that only 1.1 % of the C. difficile isolated from calves contained all four toxin genes, namely tcdA, tcdB, cdtA and cdtB. Recently, Eckert et al (2015) documented that C. difficile isolates producing only binary toxin were pathogenic despite the lack of TcdA and TcdB.…”

Rapid visual detection of binary toxin producing Clostridium difficile by loop‑mediated isothermal amplification

“…Clostridium difficile is a gram-positive toxin-producing bacillus that causes intestinal infections in humans and animals ( 1 ). C. difficile presents an emerging threat in hospital environments ( 2 ), causing a range of digestive disorders, including inflammation of the bowel, abdominal pain, fever and diarrhea ( 1 ). C. difficile infection has increased in prevalence and severity over the last decade ( 2 , 3 ).…”

Clostridium difficile in Food and Animals: A Comprehensive Review

“…As in the case of swine, the reported prevalence of C. difficile in cattle can vary wildly from one study to another depending on the geographical location studied, with percentages as diverse as 0 % in farms in North America and 60 % in Iran (Doosti and Mokhtari-Farsani 2014;McNamara et al 2011) (Table 2). Furthermore, the pathogenicity of C. difficile in cattle is not fully understood.…”