Characterization of Campylobacter jejuni isolated from pigs and man

Abstract

Twenty six rectal swabs collected from piglets below two months of age with diarrhoea/enteritis when culturally screened yielded 11 isolates of Camplobacter jejuni. Thirty two rectal swabs from children below five years of age with diarrhoea/enteritis when processed for the isolation of etiological agent, resulted in the recovery of one strain of C. jejuni. Sonicated C. jejuni antigen prepared from the selected strains of C. jejuni from porcine and human origin were found suitable for sensitization of gluteraldehyde stabilized sheep RBC for serum antibody monitoring. The sonicated antigen retained its affinity to sheep RBC even after six months of storage at – 600 C. Gluteraldehyde stabilization was found to be a suitable method for the preservation of SRBC. Gluteraldehyde stabilized SRBC stored at 40 C upto a period of three months did not show any reduction in the sensitization property, as evidenced from the PHA titre. One hundred and fifty microliters of C. jejuni antigen whose protein concentration adjusted to 2 mg/ml was found to be the optimum level for sensitisation of a suspension made from three millilitres of packed SRBC. The optimum level of SAPA cells required in the seromonitoring of C. jejuni specific antibodies by SAPA – AMHA test was found to be 0.1 per cent. Cross titration assay employing homologous and heterologous antigens of C. jejuni and the hyperimmune sera indicated that there was antigenic relationship between porcine and human strains. The results also point to the probable prevalence of different antigenic components in varying proportions in different strains from various sources. In the present investigation, 50 serum samples from pigs were monitored for the presence of C. jejuni specific antibodies by PHA and SAPA – AMHA. PHA detected 48 per cent cases as positives compared to 54 per cent by SAPA – AMHA. Statistical analysis clearly indicated that SAPA – AMHA is superior to PHA in screening C. jejuni specific antibodies. The result of the present study indicated that SAPA – AMHA test could advantageously replace the conventional PHA for serological diagnosis of animal and human Campylobacteriosis. Efforts were also made in this study to find out the change in PHA titre with homologus and heterologous antigens employing sera before and after adsorption with unsensitised SRBC to remove the non specific antibodies. Statistical analysis of the results showed that for performing PHA, homologous antigen should be preferred over heterologous antigen and when homologous antigen were used, adsorption of sera with stabilized unsensitised SRBC had no significant effect of PHA titre. Attempts were also made to study the in vitro antimicrobial sensitivity patterns of the 12 C. jejuni isolates by standard disc diffusion technique. The results indicated all the C. jejuni isolates were sensitive to chloramphenicol, gentamicin and nalidixic acid, irrespective of their source/origin. Eventhough none of the C. jejuni isolated in this study was resistant to erythromycin, only 83.3 per cent of the isolates showed a sensitive zone of inhibition, while, 16.7 per cent showed an intermediary zone of inhibition. C. jejuni isolates recorded 83.3 per cent sensitivity to furazolidone, 75 per cent to streptomycin and 58.3 per cent to ampicillin. Fifty per cent of the isolates showed resistance to oxytetracycline. Of the ten antibiotics tested, 16.6 per cent of the organism were sensitive to penicillin. C. jejuni recorded highest resistance to sulphadiazine as only 8.3 per cent of the organisms were sensitive to sulphadiazine.