Virulence gene profiles and intimin subtypes of Shiga toxin-producing Escherichia coli isolated from healthy and diarrhoeic calves.

The virulence properties of Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrhoeic and non-diarrhoeic calves were compared. The strains were also tested for O157:H7, O111 and O26 serotypes, using PCR and conventional serotyping methods. E coli strains isolated from 297 faecal samples, from 200 diarrhoeic and 97 non-diarrhoeic calves, were screened by multiplex PCR assay for the stx1, stx2, eae and Ehly virulence genes. STECs were recovered from 8 per cent of diarrhoeic calves and 10.3 per cent of non-diarrhoeic calves. The predominant virulence gene profile was stx1/eae/Ehly (47.3 per cent) among isolates from diarrhoeic calves and eae/Ehly (36.8 per cent) among isolates from non-diarrhoeic calves. Among three tested serogroups, the predominant serogroup was O26 (18.4 per cent), and O157:H7 was not detected. Intimin subtyping by restriction fragment length polymorphism analysis revealed only three intimin subtypes (ß, γ and ). A significant difference was observed in the distribution of Int- between two groups. Int- was present in 50 per cent of the isolates from diarrhoeic calves and in 11.1 per cent of the isolates from non-diarrhoeic calves; this difference was statistically significant (P=0.01).

Identification, cloning and sequencing of Escherichia coli strain chi1378 (O78:K80) iss gene isolated from poultry colibacillosis in Iran.

AIMS: To identify, clone and sequence the iss (increased serum survival) gene from E. coli strain chi1378 isolated from Iranian poultry and to predict its protein product, Iss. METHODS AND RESULTS: The iss gene from E. coli strain chi1378 was amplified and cloned into the pTZ57R/T vector and sequenced. From the DNA sequence, the Iss predictive protein was evaluated using bioinformatics. Iss from strain chi1378 had 100% identity with other E. coli serotypes and isolates from different origins and also 98% identity with E. coli O157:H7 Iss protein. Phylogenetic analysis showed no significant different phylogenic groups among E. coli strains. CONCLUSIONS: The strong association of predicted Iss protein among different E. coli strains suggests that it could be a good antigen to control and detect avian pathogenic E. coli (APEC). SIGNIFICANCE AND IMPACT OF THE STUDY: Because the exact pathogenesis and the role of virulence factors are unknown, the Iss protein could be used as a target for vaccination in the future, but further research is required.

Detection and identification of Salmonella Typhimurium in bovine diarrhoeic fecal samples by immunomagnetic separation and multiplex PCR assay.

The aim of this study was to use the immunomagnetic separation (IMS) test plus a multiplex polymerase chain reaction (m-PCR) assay to detect Salmonella at genus level and also for the identification of Salmonella enterica serovar Typhimurium in bovine diarrhoeic fecal samples. In all, 400 bovine diarrhoeic fecal specimens were examined by conventional bacterial culture, IMS, and m-PCR. For m-PCR assay, four set primers were selected: 139-141, specific for inv-A gene of Salmonella spp and the RfbJ, FliC and FljB, specific for the rfbJ, FliC and fljB genes of Salmonella Typhimurium or other Salmonella serovars with similar antigenic properties. Thirty-three (8.25%) out of the 400 fecal samples were culture positive for Salmonella serovars. Of these, 66.7% (22 of 33) were Salmonella enterica serovar Typhimurium, and 9.1% (three of 33) were serovar Dublin. In the IMS + m-PCR, four amplified product (663, 526, 284 and 183 bp) were found in all specimens that had serovar Typhimurium (4,5,12:i:1,2), they corresponded, respectively, to the rfbJ, fljB, inv-A and Flic genes of this serovar. In serovar Dublin (1,9,12:g,p:-), Georgia (6,7:b:e,n,z(15)) and, Enteritidis (1,9,12;g,m:-) only one PCR product (284 bp) was amplified from the inv-A gene. In serovars Augustenborg (6,7:i:1,2) and Lindenburg (6,8:i:1,2) three positive bands (526, 284 and 183 bp) were amplified corresponding to the fljB, inv-A and Flic genes, respectively. In serovar Virchow (6,7:r:1,2) two amplified products (284 and 526 bp) from the inv-A and FliC genes were observed. In serovar Gloucster (1,4,12(27):i:1,w) three fragments (183, 284 and 663) from the FliC, inv-A and, rfbJ genes respectively, were observed. In the positive control as expected, four PCR products were amplified corresponding to the FliC, inv-A, fljB and rfbJ genes, respectively. In conclusion, the results of this study showed that detection of Salmonella at genus level with universal ST139-141 primers and identification of Salmonella Typhimurium by using specific primers of O4, H(2):1, 2 and H(1) antigens can potentially permit to more readily evaluate fecal and other types of samples for the presence of these organisms. Compared to bacteriological culture the combination of IMS and m-PCR resulted a faster method for the detection and identification of Salmonella at genus and serovar level by using of universal and specific primers.

IS200 fingerprinting of Salmonella enterica serotype Abortusovis strains isolated in Iran.

Salmonella enterica serovar Abortusovis is one of the most common pathogens responsible for abortion in sheep. In Iran, the spread of Abortusovis is highly dependent on the nomadic life style. In this study we performed IS200 fingerprinting to identify the clonal lines circulating in Iran. All the isolates contained 4 or 5 copies of the transposon and could be classified in 4 genotypes. A single genotype was highly prevalent and very likely it has circulated in Iran since 1970. All the isolates showed a high degree of relatedness.

Traditional methods used for controlling animal diseases in Iran.

In ancient times in Iran, infectious diseases of animals and human beings were referred to as choleraic diseases. Rhazes (9th century), followed by Avicenna (10th century), Jorjani (11th century) and others, had specific opinions on the cause and effect relationship in these diseases, which recall the fermentation theory of Louis Pasteur. In ancient Iran, the methods adopted for veterinary procedures were those of general theoretical and practical medicine, including the humoral theory, accurate diagnosis, signs and symptoms, and the prescription of herbal and mineral medicines or substances of animal origin. If herbal treatment failed, cauterisation and surgery were used. When refractory and contagious infectious diseases occurred, animals were evacuated from the infected region, in order to preserve their health, with resort to the mercy of Allah (God) as a final remedy. Iranian scientists of ancient times had interesting views on rabies. A kind of serotherapy was used for treating persons bitten by rabid dogs. Vaccination was performed many centuries ago by using dried smallpox lesions. In Baluchistan (Iran), infants were encouraged to play with and touch the teats of cows affected with cowpox, in order to immunise the children against smallpox, and this was centuries before the discovery of smallpox vaccine by Edward Jenner. Camelpox was also used for human immunisation. In the case of caprine pleuropneumonia, an extract or juice was obtained from the lungs of affected animals and was inactivated by treatment with certain herbal medicines which had a disinfectant effect. A thread coated with this extract was passed through the ear of healthy goats to render them immune. The author lists various diseases and their treatment. This work forms part of detailed research by the author with reference to some 2,200 books and many ancient manuscripts on the history of veterinary science in Iran.