Epidemiological, bacteriological and molecular studies on caseous lymphadenitis in Sirohi goats of Rajasthan, India

Molecular Characterization and Antimicrobial Susceptibilities of Corynebacterium pseudotuberculosis Isolated from Caseous Lymphadenitis of Smallholder Sheep and Goats

Caseous lymphadenitis (CLA) is a bacterial infection caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that affects sheep and goats, leading to abscess formation in their lymph nodes. The present study aimed to isolate and identify C. pseudotuberculosis from CLA in smallholder sheep and goats, and determine the resistance patterns, virulence, and resistance genes of the isolates. Additionally, genotypic and phylogenetic analysis of the isolates was conducted using ERIC-PCR and DNA sequencing techniques. A cross-sectional study examined 220 animals (130 sheep and 90 goats) from 39 smallholder flocks for clinical signs of CLA. Fifty-four (24.54%) animals showed CLA-compatible lesions, confirmed by C. pseudotuberculosis isolation and PCR identification. Sheep had a lower infection rate of CLA (18.46%) compared with goats (33.3%). Antimicrobial susceptibility testing of 54 C. pseudotuberculosis isolates to 24 antimicrobial drugs revealed that they were 100% resistant to bacitracin and florfenicol, while none of the isolates were resistant to norfloxacin. A high resistance rate was observed for penicillin and erythromycin (92.6% each). Interestingly, 16.7% of C. pseudotuberculosis isolates recovered from sheep showed vancomycin resistance. Molecular characterization of C. pseudotuberculosis isolates revealed that PLD, PIP, and FagA virulence genes were present in all examined isolates. However, the FagB, FagC, and FagD genes were detected in 24 (100%), 20 (83%), and 18 (75%) of the sheep isolates, and 26 (87%), 26 (87%), and 18 (60%) of the goat isolates, respectively. The β-lactam resistance gene was present in all isolates. Furthermore, 83% of the sheep isolates carried the aminoglycoside (aph(3″)-lb), chloramphenicol (cat1), and bacitracin (bcrA) resistance genes. Among the isolates recovered from goats, 73% were found to contain macrolides (ermX), sulfonamide (sul1), and bacitracin (bcrA) resistance genes. It is worrisome that the glycopeptide (vanA) resistance gene was detected in 8% of the sheep isolates as a first report. ERIC-PCR genotyping of 10 multi-drug-resistant C. pseudotuberculosis isolates showed a high similarity index of 83.6% between isolates from sheep and goats. Nucleotide sequence analysis of partial 16S rRNA sequences of C. pseudotuberculosis revealed 98.83% similarity with biovar Ovis of globally available reference sequences on the Genbank database. Overall, our findings might indicate that C. pseudotuberculosis infection in smallholders in Egypt might be underestimated despite the significant financial impact on animal husbandry and potential health hazards it poses. Moreover, this study highlights the importance of implementing a sustainable control strategy and increasing knowledge and awareness among smallholder breeders to mitigate the economic impact of CLA.

Cytopathological and bacteriological studies on caseous lymphadenitis in cattle slaughtered at Bishoftu municipal abattoir, Ethiopia

Background

Caseous lymphadenitis (CLA) is a chronic bacterial infectious disease that affects cattle, shoats, and other domestic and wild ruminants.

Methods

A purposive cross‐sectional study was conducted on 30 cattle with enlarged lymph nodes to investigate CLA using cytopathological and bacteriological techniques from cattle slaughtered at Bishoftu municipal abattoir.

Results

From a total of 30 cattle subjected to clinical and post‐mortem examinations, only one bull was found to be infected with a rare case of CLA in Bishoftu municipal abattoir, Ethiopia. Enlargement of the pre‐scapular lymph node was the only clinical finding during ante‐mortem inspection of the bull. The gross pathological lesion showed a pre‐scapular lymph node with a caseo‐necrotic dystrophic calcification that was accompanied by a rough texture and white to grayish hue. Histopathologically, the lymph node was characterized by central liquefactive necrosis that was surrounded by coagulative necrosis containing multiple foci of mineralization, infiltration of polymorphonuclear neutrophils and mononuclear immature fibrosis containing inflammatory cells and also with some sort of a thick layer of mature fibrosis that defines the magnitude of the lesion. Cytologically, multi‐lobulated (intact and degenerated) neutrophils, a few reactive lymphocytes, macrophages and some crenated histocytes have been recognized. The bacterial culture of the sample revealed small, white cream, dry, waxy colonies with a narrow area of β‐haemolysis. The isolate of the sample was a Gram‐positive cocci‐bacilli that was arranged in a Chinese pattern on Gram staining, and catalase and urease were positive in the biochemical analysis of this organism, which was able to ferment glucose and maltose but not trehalose and xylose.

Conclusions

The present investigation indicated that CLA was prevalent as sporadic cases among cattle slaughtered in Bishoftu municipal abattoir. Thus, effective preventive and control measures, such as good sanitation and hygiene, should be followed during meat inspection.

A journey through the Corynebacterium pseudotuberculosis proteome promotes insights into its functional genome

Background

Corynebacterium pseudotuberculosis is a Gram-positive facultative intracellular pathogen and the etiologic agent of illnesses like caseous lymphadenitis in small ruminants, mastitis in dairy cattle, ulcerative lymphangitis in equines, and oedematous skin disease in buffalos. With the growing advance in high-throughput technologies, genomic studies have been carried out to explore the molecular basis of its virulence and pathogenicity. However, data large-scale functional genomics studies are necessary to complement genomics data and better understating the molecular basis of a given organism. Here we summarize, MS-based proteomics techniques and bioinformatics tools incorporated in genomic functional studies of C. pseudotuberculosis to discover the different patterns of protein modulation under distinct environmental conditions, and antigenic and drugs targets.

Methodology

In this study we performed an extensive search in Web of Science of original and relevant articles related to methods, strategy, technology, approaches, and bioinformatics tools focused on the functional study of the genome of C. pseudotuberculosis at the protein level.

Results

Here, we highlight the use of proteomics for understating several aspects of the physiology and pathogenesis of C. pseudotuberculosis at the protein level. The implementation and use of protocols, strategies, and proteomics approach to characterize the different subcellular fractions of the proteome of this pathogen. In addition, we have discussed the immunoproteomics, immunoinformatics and genetic tools employed to identify targets for immunoassays, drugs, and vaccines against C. pseudotuberculosis infection.

Conclusion

In this review, we showed that the combination of proteomics and bioinformatics studies is a suitable strategy to elucidate the functional aspects of the C. pseudotuberculosis genome. Together, all information generated from these proteomics studies allowed expanding our knowledge about factors related to the pathophysiology of this pathogen.

Atypical Multibacterial Granulomatous Myositis in a Horse: First Report in Italy

Infectious causes of myositis are reported relatively uncommonly in horses. Among them, bacterial causes include Streptococcus equi subsp. zooepidemicus, Actinobacillus equuli, Fusobacterium spp. Staphylococcus spp, and Corynebacterium pseudotuberculosis. Infection can be spread to muscles via haematogenous or extension from skin lesions. Parasitic myositis has also been documented. In this report, a 12 year-old Italian Quarter Horse mare presented with diffuse subcutaneous nodules and masses ranging from 2 × 3 to 5 × 20 cm in size, and adherent to subcutis and muscles that were first macroscopically and cytologically diagnosed as pyogranulomas. Subsequently, histological, molecular, bacteriological, and biochemical investigations were performed. All the data obtained allowed to diagnose a severe and diffuse multibacterial granulomatous myositis caused by Corynebacterium pseudotuberculosis and Corynebacterium amycolatum. Following the therapy and an initial disappearance of most of the lesions together with a general improvement of the mare, the clinical condition deteriorated, and new nodules appeared. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and PCR techniques revealed the presence of bacteria as Glutamicibacter creatinolyticus and Dietzia spp. To the authors’ knowledge, this case report represents the first description of multibacterial granulomatous myositis due to Corynebacterium pseudotuberculosis, Corynebacterium amycolatum, Glutamicibacter creatinolyticus, and Dietzia spp. in a horse reared in Italy.

Molecular identification of Corynebacterium pseudotuberculosis in sheep

Caseous lymphadenitis is still a serious zoonotic problem in Turkey. Sheep suffer from the disease with yield loss in wool and meat production. Moreover, with inexperienced laboratory staff, biochemical identification may go unrevealed. The scope of this study was to demonstrate the presence of Corynebacterium pseudotuberculosis in sheep by PCR. The sampling was conducted via collecting lymph fluids from the lymph node internal pouch wall of 100 sheep that were examined for the presence of Corynebacterium pseudotuberculosis. Molecular identification of the Corynebacterium pseudotuberculosis isolates was carried out by establishing the presence of the proline iminopeptidase gene. All isolates were confirmed to be Corynebacterium pseudotuberculosis by polymerase chain reaction. The polymerase chain reaction procedure conducted in this research was observed to be reliable and fast, and could be utilized for confirmation of caseous lymphadenitis in sheep as an optional technique to time-consuming biochemical identification methods.