To identify strains of Mycobacterium bovis circulating in Iran, we used region of difference, spoligotypes, and variable number tandem repeats to genotype 132 M. bovis isolates from Holstein Friesian cattle. Despite wide geographic origins, the strains were genetically homogeneous. Increased distribution of cattle herds and inadequate control measures may have contributed to strain dispersion. E stimates suggest that globally >50 million cattle are infected with Mycobacterium bovis, causing an annual loss of ≈$3 billion US (1). In Asia, 94% of the 460-million cattle herd (33% of the world's cattle) are in areas with either no or only partial tuberculosis (TB) control programs (2). In 2006, the prevalence of bovine TB in Iran was 0.12% (Iranian Veterinary Organisation [IVO], unpub. data), yet few studies have been conducted on M. bovis in Iran (3-5). To identify the strains of M. bovis in Iran, we used region of difference (RD) typing, spoligotyping, and variable number tandem repeats (VNTR) typing. The StudyFrom 1996 through 2003, we collected necropsy specimens from TB-test reactor cattle from abattoirs in 21 of the 28 Iranian provinces where bovine TB has been reported. Specimens were all respiratory and gastrointestinal lymph nodes and any lungs, spleens, or livers that were visibly affected. All specimens were cultured for M. tuberculosis complex bacteria and incubated for >10 weeks. Of the 470 animals tested, results were positive for 216; however, because of delays in exporting samples to the United Kingdom, only 132 samples contained reculturable isolates with suffi cient growth for DNA extraction. Molecular speciation was determined by RD-PCR (RD1, RD5, RD9, RD10, and RD11) (6). Spoligotyping was conducted according to the method of Kamerbeek et al. RD-PCR showed that all 132 isolates were M. bovis. Spoligotyping identifi ed 8 types (Figure 1). SB0120 was the most common, and 5 others (SB1167-SB1171) were novel patterns and, thus, were specifi c to Iran. VNTR typing identifi ed 23 profi les (Figure 2). ConclusionsRD typing of the 132 isolates confi rmed that they were all wild type M. bovis; none were the M. bovis BCG vaccine strain because they carried the RD1 region. This fi nding is noteworthy because unauthorized vaccination of cattle with BCG has been reported in Iran (IVO, unpub. data). Although previous studies in Iran have reported the isolation of M. tuberculosis from tuberculin-positive cattle (3), our RD9 and RD10 analyses indicated that no isolates were M. tuberculosis. This fi nding suggests that M. tuberculosis is unlikely to be abundant, if even present, on cattle farms of Iran. Similarly, RD5 and RD11 analyses indicated that no isolates were M. africanum or M. microti.The spoligotypes were either identical to the BCG-like (SB0120) pattern (41% of isolates) or were simple variants of it by the deletion of 1 or occasionally 2 single or contiguous blocks of spacers (Figure 1). Because spoligotype changes have been attributed solely to the deletion of spacer units, the BCG-like strains here ...

Mycobacterium bovis is the cause of bovine tuberculosis (bovine Tb) in animals and is considered to be zoonotic and accordingly it infects humans, although cattle are the main host. Buffalo can also be infected and develop bovine Tb. In Iran, almost half a million buffaloes are farmed, mainly in three provinces. In West Azerbaijan, which has the largest numbers of buffaloes, cattle and buffalo are often farmed together. According to the reports of the Iranian Veterinary Organization over the last 25 years, there have been no reports of bovine Tb in buffalo, although the disease is often reported in cattle in this province. Eighteen and 140 pathology specimens from cattle and buffalo, respectively, collected from West Azerbaijani abattoirs were cultured. From one buffalo specimen out of 140, M. bovis was recovered, whereas the pathogen was isolated from 13 cattle specimens. Spoligotyping showed a relatively higher polymorphism within these isolates compared with M. bovis isolated from other Iranian provinces.