Presence of Clostridioides difficile in cattle feces, carcasses, and slaughterhouses: Molecular characterization and antibacterial susceptibility of the recovered isolates

The aims of this study were to isolate and identify Clostridioides difficile from cattle feces and carcasses, and slaughterhouse samples, and to determine the molecular characteristics and antibacterial susceptibility of the recovered isolates. A total of 220 samples, including 100 cattle fecal samples, 100 cattle carcass surface samples, and 20 slaughterhouse samples were used as the study material. In total, 12 (5.45%) samples, including 11 (11%) cattle fecal samples and 1 (5%) slaughterhouse sample, were found to be positive for C. difficile. On the other hand, all of the carcass samples were negative for C. difficile. A total of 11 (91.66%) isolates, including 10 fecal isolates and 1 slaughterhouse wastewater isolate, were found to be positive for the presence of the toxin genes tcdA and tcdB, whilst 1 fecal isolate was found to be negative for both genes. In addition, 3 different ERIC-PCR profiles were identified in the 11 fecal isolates. The ERIC-PCR profile of the slaughterhouse wastewater isolate was found to be similar to one of the ERIC-PCR profiles obtained from the fecal isolates. All of the isolates were resistant to ciprofloxacin and levofloxacin. Considering that the agent is a spore-forming bacterium shed in feces, the detection of C. difficile isolates of different genotypes, some carrying toxin genes, suggests that feces and slaughterhouse wastewater carrying this bacterium may pose a risk for the contamination of carcasses. The current study revealed that hygiene conditions should be performed to the maximum extent in slaughterhouses.

Effect of a commercial steam-vacuuming treatment implemented after slaughtering for the decontamination of cattle carcasses

To assess the antimicrobial effect of a commercial steam-vacuuming system newly implemented after slaughtering, 105 cattle carcasses were examined for total viable counts (TVC) at four different areas. Before steam vacuuming, mean TVC of the excision samples were comparable at the perineal area and brisket (3.0-3.1 log CFU cm-2) or the hind leg and shoulder (2.6-2.7 log CFU cm-2). Steam vacuuming reduced mean TVC by 0.9, 0.7, 0.6, and 0.4 log CFU cm-2 at the perineal area, hind leg, shoulder, and brisket, respectively. With regard to the distribution of counts, steam vacuuming increased the proportion of TVC results <3.0 log CFU cm-2 from 74.8% (62.9-87.6% at carcass areas) to 86.7% (71.4-97.1% at carcass areas). Thus, steam vacuuming after slaughtering might be useful for the reduction of contamination in designated carcass areas, but the effect must not be overestimated and decontamination treatments always must be seen part of an integral food safety system.

Tuberculosis in slaughtered cattle and workers in some abattoirs of Baghdad governorate

OBJECTIVE/BACKGROUND

Tuberculosis (the white plague) is regarded as one of the most widespread infectious diseases and continues to be a leading cause of death and the most prominent public health problem worldwide. It is caused by Mycobacterium tuberculosis complex, which refers to a group of seven species; one of them known as Mycobacterium bovis-the cause of bovine-type tuberculosis-has an exceptionally wide host range. It infects cattle, humans, goats, cats, dogs, buffalo, and deer. Many susceptible species, including man, are spillover hosts in which infection is not self-maintaining. The objective of this study is to investigate the role of infected slaughtered cattle in spreading tuberculosis to those who work in abattoirs.

METHODS

Three hundred slaughter cattle in some abattoirs of the Baghdad governorate were examined grossly. Tissue samples were taken from lesions that had appeared on lymph nodes, lung, liver, spleen, peritoium, and intestines. A routine examination was performed: (1) smear for Ziehl Neelsen acid-fast stain; (2) cultured: each sample was cultured on Stone-brink with sodium pyrovite and on Lowenstein media which contain glycerol; and (3) incubated at 37°C for 4-10weeks, to observe the characteristic features of bacterial colonies. Biochemical tests, nitrate reduction, urea analysis, tween 80 lysis, and catalase test were employed to isolate and identify the bacteria. Pieces from tissue samples were kept in 10% formalin for histopathological investigation. Tuberculin tests and X-rays were conducted for 186 workers who were in contact with slaughtered cattle in the same abattoirs, with an age range of 15years to 60years. Sputum samples were collected from all workers in clean and sterile containers, and subjected to the same routine examination. The collection of samples was carried out under strict and sterile conditions and the sputum was kept in 50% oxalic acid for 20 min before culture on media to avoid the contamination.

RESULTS

Gross examination of cattle carcasses showed tubercle in four of them that was distributed in lymph nodes and different organs especially in lungs, livers, and in one case tubercle appeared on the peritoneum and intestines. A histopathological study revealed different lesions with an accumulation of lymphocytes and macrophages in lymph nodes and organs. Four isolates of M. bovis were diagnosed and identified by routine examination that indicated the percentage of infection in slaughtered cattle was 1.33%. The result of the workers' examinations clarified that only one of the workers had a positive result for the tuberculin test, whereas three of them had positive results in X-ray and routine examination. Three isolates were obtained from workers (1.6%); two of these isolates were diagnosed as M. bovis and the other as M. tuberculosis.

CONCLUSION

The main conclusion of this study is that two workers were infected with cattle's strain which confirms the role of slaughtered cattle in the transmission of this dangerous, chronic, and zoonotic disease to man.