BACKGROUND: Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis (CLA), a chronic and very common disease in sheep and goats, which can lead to severe economic losses in the livestock industry.OBJECTIVES: This study aims to investigate the prevalence of CLA in sheep in Kurdistan province of Iran using phenotypic and molecular methods, and assess the antibiotic resistance of isolated Corynebacterium pseudotuberculosis.METHODS: In this study, from September to March 2022, 270 samples of skin abscesses were collected from sheep in livestock farms of Kurdistan province. Immediately, using the cold chain system, the samples were transferred to the microbiology laboratory of the Faculty of Medicine at Kurdistan University of Medical Sciences. Identification of isolates was done using biochemical tests and polymerase chain reaction (PCR) method. The antibiotic resistance of the isolates was examined using the Kirby-Bauer disk diffusion method.RESULTS: Based on biochemical tests, out of 270 samples, 82 suspected to have Corynebacterium pseudotuberculosis. Out 82 samples, the presence of bacteria was confirmed in 76 samples by the PCR. The antibiotic sensitivity test showed that the isolates had high sensitivity to doxycycline and ceftriaxone and high resistance to streptomycin and kanamycin.CONCLUSIONS: The CLA has a high prevalence in sheep in Kurdistan province. According to high resistance rate of Corynebacterium pseudotuberculosis to streptomycin and kanamycin, it recommended to avoid treatment of CLA cases with these antibiotics.

BACKGROUND: Corynebacterium pseudotuberculosis and Trueperella pyogenes are two important pyogenic bacteria that cause many annual economic losses worldwide. Currently, antibiotic resistance of these bacteria is on the rise. Early detection of infection with these bacteria is important for controlling the infections caused by these two bacteria.OBJECTIVES: This study aimed to investigate the contamination of cattle cutaneous abscesses with  Corynebacterium pseudotuberculosis and Trueperella pyogenes in five large cattle farms around Tehran and propose an accurate method for a rapid detection of these two bacteria.METHODS: Out of 60 cows involved in cutaneous abscesses in the summer of 2018, sterile sampling was performed to diagnose the bacterial agent that caused the abscess. Bacteriological examination of the samples was performed using standard biochemical reactions and polymerase chain reaction using specific primers.RESULTS: Of the 60 samples studied, 25 % (15.60) were isolated as Corynebacterium pseudotuberculosis and 20 % (12.60) as Trueperella pyogenes. In 55 % of the samples (33.60), both bacteria were present simultaneously. All the samples detected using biochemical reactions were confirmed by the polymerase chain reaction.CONCLUSIONS: Corynebacterium pseudotuberculosis and Trueperella pyogenes are the main causes of cutaneous abscess in cattle farms around Tehran. Because the accurate diagnosis of the cause of abscesses is very important for effective treatment, polymerase chain reaction, based on 16S-23S rDNA and 16S rRNA, can be used to rapidly and accurately detect these bacteria in the early stages of the infection.

BACKGROUND: Caseous lymphadenitis, caused by Corynebacterium pseudotuberculosis, is one of the most important diseases of sheep and goats, causing considerable losses for herd owners. Phospholipase D (PLD) is a potent exotoxin produced by C. pseudotuberculosis and it has been considered as the major virulence factor for this bacterium, possibly contributing to the spread of the bacteria from the initial site of infection to secondary sites within the host. Heat shock proteins (HSPs) are important candidates for the development of vaccines because they are usually able to promote both humoral and cellular immune responses in mammals. OBJECTIVES: The aim of this study was the cloning and expression of the PLD and HSP60 genes of C. pseudotuberculosis, used subsequently to evaluate the protectivity of these recombinant proteins for vaccine development against this bacterium. METHODS: PLD and HSP60 genes were cloned into pMAL-c2X vector and recombinant plasmids construct was transformed to DH5 strain of E. coli. Expression of the proteins was shown by SDS-PAGE and accuracy of the cloned genes was confirmed by nucleotide sequence analysis. RESULTS: The transformed E. coli strain DH5 expressed PLD and HSP60 proteins effectively. The expressed fusion protein was found almost entirely in the soluble form. CONCLUSIONS: In the following studies the immunogenicity and protectivity of these recombinant proteins against C. pseudotuberculosis infections can be assessed.