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High mortalities in 17 canary flocks from different regions of Tehran, Iran, were reported. Necropsy and histopathologic examination revealed necrotic hepatitis and overall congestive septicaemia in carcasses. Salmonella enterica was isolated from 34 examined samples, two samples from each flock, including visceral organs of carcasses and droppings of live diseased birds. All isolates were typed as Salmonella enterica serovar Typhimurium by conventional serotyping. Antibiotic resistance profiling using 33 antibiotics and random amplification of polymorphic DNA differentiation by three primers were performed and showed an identical clonal relationship between these isolates and S. Typhimurium isolated from a sample of feedstuffs. Changing the feed ingredients along with antibiotic therapy via the drinking water by enrofloxacin solution controlled the outbreaks, and mortalities ceased. The zoonotic nature of S. Typhimurium and close contact of bird owners with pet birds in the home environment made the case significant in relation to public health.

The purpose of this study was to determine the utility of RAPD-PCR and antibiotic susceptibility tests in differentiation of S. typhimurium isolates in Iran. Thirty isolates of S. typhimurium, selected based on animal source; place and time of the isolation and a reference strain of the bacterium were used in this study. Serotyping of the isolates was performed by reliable antisera and confirmed with a multiplex PCR. Genomic DNAs were extracted and subjected to an optimized RAPD-PCR, using two previously reported arbitrary primers (P1254 and 23L). Bacteria were also examined for resistance against 8 antibiotics, using a standard antibiotic susceptibility test. While the antibiotic susceptibility test resulted in the identification of 13 profiles of R-type among the bacterial isolates, application of primers P1254 and 23L in the RAPD-PCR could discriminate the isolates only in four and six profiles respectively. However, combination of the two methods could differentiate the 30 isolates in 20 different profiles. The results of this study indicate that the discriminatory power of RAPD-PCR for S. typhimurium is low but a combination of this method with antibiotic susceptibility test could be considered an easy and relatively reliable discriminatory approach in differentiation of S. typhimurium for epidemiologic purposes in Iran.

Genomic and phenotypic evaluation of Salmonella typhimurium and Salmonella enteritidis by two simple, fast, and applicable methods of random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) and antibiotic susceptibility for employment in epidemiologic surveillance screening systems in Iran was the objective in this study. We selected 60 (30 S. typhimurium and 30 S. enteritidis) isolates from different animal sources and different times and places among 1975–2006 in Iran. Serotyping with traditional method and reliable antisera was done and then confirmed with multiplex PCR (with four and three pair of primers, respectively). All of S. typhimurium and S. enteritidis isolates have virulence genes of invA and spv, respectively. Then, from nine primers, two primers that have enough discriminatory power were selected for RAPD analysis. We set up the quality and quantity of DNA template, primers, MgCl2, Taq DNA polymerase, and deoxyribonucleotide triphosphates concentration for RAPD analysis. We also examined the strains with disk diffusion standard antibiotic susceptibility test. With the application of primer P1254; we saw four and seven and primer 23L, six and three profiles in RAPD analysis and 13 and six profiles of R-type in susceptibility test of S. typhimurium and S. enteritidis, respectively. Combination of two methods differentiated these 30 strains to 20 and 16 different profiles, respectively. The finding of this study indicated that clonality of S. enteritidis is more than S. typhimurium in Iran and RAPD-PCR in combination with antibiotic susceptibility test were fast, easy, relatively reliable, and discriminatory molecular and phenotypic methods in the differentiation of S. typhimurium and S. enteritidis for epidemiologic purposes in Iran. [ABSTRACT FROM AUTHOR]