Serology and clinical relevance of Corynebacterium pseudotuberculosis in native Korean goats (Capra hircus coreanae)

Molecular characterization and antimicrobial susceptibility of Corynebacterium pseudotuberculosis isolated from skin abscesses of native Korean goats (Capra hircus coreanae)

AIMS

This study aimed to investigate the molecular characterization and antimicrobial susceptibility of C. pseudotuberculosis from skin abscesses of Korean native black goats (KNBG, Capra hircus coreanae) in South Korea.

METHODS AND RESULTS

A total of 83 isolates were recovered from skin abscesses of KNBG. Of these isolates, 74 isolates were identified as C. pseudotuberculosis by phospholipase D (PLD) gene-based PCR assay. Each of the isolates possessed all 18 virulence genes (FagA, FagB, FagC, FagD, SigE, SpaC, SodC, PknG, NanH, OppA, OppB, OppC, OppD, OppF, CopC, NrdH and CpaE). The genetic diversity of C. pseudotuberculosis isolates was assessed by the phylogenetic analysis using the concatenated sequences (3,073 bp) of five housekeeping genes (fusA, dnaK, infB, groeL1, and leuA) for investigating their genetic diversity. In the results, the isolates belonged to three groups: group 1 (67 isolates), group 2 (one isolate), and group 3 (six isolates) within biovar ovis. However, the groups exhibited low genetic diversity (0.20~0.41%). In the antimicrobial susceptibility test, most isolates were susceptible to tetracycline, vancomycin, chloramphenicol, ciprofloxacin, erythromycin, enrofloxacin, cefoxitin, ampicillin, gentamycin, cephalothin, and doxycycline, whereas they were not susceptible to cefotaxime, trimethoprim, and streptomycin.

CONCLUSION

This results suggest the involvement of relatively few clones of C. pseudotuberculosis in Korea. Further, present isolates can threaten public health due to potentially virulent strains with all 18 virulence genes and non-susceptible strains to clinically important antibiotics (CIA) and highly important antibiotics (HIA).

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is the first to investigate the genetic diversity and potential pathogenicity of C. pseudotuberculosis biovar ovis isolates from skin abscesses of KBNG in South Korea, and could provide useful information in controlling its infections.

Utility assessment of an Enzyme-linked immunosorbent assay for detection of subclinical cases of caseous lymphadenitis in small ruminant flocks

The actual prevalence of CLA (caseous lymphadenitis) in small ruminant flocks is underestimated in many countries, and because it is not a notifiable disease, it will continue to spread without data and information about its real economic impact. The difficulty in the accurate identification of the causative agent in internal subclinical cases allows the disease to spread within and between flocks. This research intends to assess the utility of an ELISA (enzyme‐linked immunosorbent assay) test in the detection of internal subclinical cases of CLA in farms and to simultaneously add data on the seroprevalence of the disease in Portugal. Sera from 756 small ruminants, 70% sheep (528/756) and 30% goats (228/756) were screened for antibodies against Corynebacterium pseudotuberculosis using the ELISA technique based on a recombinant phospholipase D (ELITEST CLA # CK105A^®). The animals showing internal lesions (n ꞊ 58) were sampled for the identification of the aetiological agent. In this investigation, the prevalence of CLA was 34% (258/756), with the ELISA test showing a low specificity (78%) and high sensitivity (100%). The proof was able to detect 57% (13/23) of subclinical cases of CLA confirmed by postmortem examination and conventional PCR (polymerase chain reaction). The results also reveal that goats have a higher propensity for the disease, and dairy farms and non‐extensive production units appear to be more susceptible to CLA. This research clarifies an actual problem and pointed out the importance of CLA in small ruminant herds in Portugal. Finally seems to demonstrate that the ELISA test is a good diagnostic tool for use in CLA eradication programmes.

Corynebacterium pseudotuberculosis mastitis in Egyptian dairy goats

Background and Aim:

Mastitis is an important threat facing goat milk industry and is the most common cause of culling. Efficient control of mastitis, based on efficient diagnosis of diseased animals, would improve milk production and reproductive efficiency. In subclinical mastitis (SCM), infected goats demonstrate neither udder symptoms nor abnormal milk. Corynebacterium pseudotuberculosis is an infectious causative agent of mastitis, mostly results as an extension of infection from the supramammary lymph node, and causes financial losses in the goat industry. This study aimed to estimate the prevalence of SCM with emphasis on C. pseudotuberculosis mastitis in Egyptian dairy goats in the selected farms.

Materials and Methods:

A total of 336 half milk samples were collected from 177 dairy goats of various crossbreeds, in mid-to-late lactation period, after clinical examination. All samples were examined bacteriologically, while somatic cell count (SCC) was determined only in 180 half milk samples of the clinically healthy milk samples. The isolated and identified C. pseudotuberculosis was examined for evidence of virulence genes (Phospholipase D [pld] and β-subunit of RNA polymerase [rpoB]) by polymerase chain reaction (PCR).

Results:

The prevalence of clinical mastitis was 30.5%, while 69.5% of animals were apparently healthy and secreted milk was normal. Of those 180 clinically healthy half milk samples, 96 milk samples (53.33%) showed SCM as detected by SCC (SCC ≥1,000,000 cells/ml). Coagulase-negative staphylococci were the most prevalent bacteria (41.96%), then Staphylococcus aureus (37.5%) and C. pseudotuberculosis (7.14%). Molecular diagnosis of virulence genes revealed evidence of pld gene in 16 isolates (66.66%), and rpoB gene in 6 samples (25%) of the 24 bacteriologically isolated C. pseudotuberculosis. Here, we describe, for the 1^st time, isolation and identification of C. pseudotuberculosis from milk of does suffering from SCM in Egypt.

Conclusion:

C. pseudotuberculosis must be considered for routine bacteriological examination of milk from dairy goats, particularly herds with a history of caseous lymphadenitis. Pld gene-based PCR is more reliable than rpoB gene-based ones for the diagnosis of C. pseudotuberculosis.

UvrB protein of Corynebacterium pseudotuberculosis complements the phenotype of knockout Escherichia coli and recognizes DNA damage caused by UV radiation but not 8-oxoguanine in vitro

In prokaryotic cells, the UvrB protein plays a central role in nucleotide excision repair, which is involved in the recognition of bulky DNA lesions generated by chemical or physical agents. The present investigation aimed to characterize the uvrB gene of Corynebacterium pseudotuberculosis (CpuvrB) and evaluate its involvement in the DNA repair system of this pathogenic organism. In computational analysis, the alignment of the UvrB protein sequences of Escherichia coli, Mycobacterium tuberculosis, Bacillus caldotenax and Corynebacterium pseudotuberculosis showed high similarity and the catalytic amino acid residues and functional domains are preserved. A CpUvrB model was constructed by comparative modeling and presented structural similarity with the UvrB of E. coli. Moreover, in molecular docking analysis CpUvrB showed favorable interaction with EcUvrA and revealed a preserved ATP incorporation site. Heterologous functional complementation assays using E. coli uvrB-deficient cells exposed to UV irradiation showed that the CpUvrB protein contributed to an increased survival rate in relation to those in the absence of CpUvrB. Damaged oligonucleotides containing thymine dimer or 8-oxoguanine lesion were synthesized and incubated with CpUvrB protein, which was able to recognize and excise UV irradiation damage but not 8-oxoguanine. These results suggest that CpUvrB is involved in repairing lesions derived from UV light and encodes a protein orthologous to EcUvrB.

In silico identification of essential proteins in Corynebacterium pseudotuberculosis based on protein-protein interaction networks

Background

Corynebacterium pseudotuberculosis (Cp) is a gram-positive bacterium that is classified into equi and ovis serovars. The serovar ovis is the etiological agent of caseous lymphadenitis, a chronic infection affecting sheep and goats, causing economic losses due to carcass condemnation and decreased production of meat, wool, and milk. Current diagnosis or treatment protocols are not fully effective and, thus, require further research of Cp pathogenesis.

Results

Here, we mapped known protein-protein interactions (PPI) from various species to nine Cp strains to reconstruct parts of the potential Cp interactome and to identify potentially essential proteins serving as putative drug targets. On average, we predict 16,669 interactions for each of the nine strains (with 15,495 interactions shared among all strains). An in silico sanity check suggests that the potential networks were not formed by spurious interactions but have a strong biological bias. With the inferred Cp networks we identify 181 essential proteins, among which 41 are non-host homologous.

Conclusions

The list of candidate interactions of the Cp strains lay the basis for developing novel hypotheses and designing according wet-lab studies. The non-host homologous essential proteins are attractive targets for therapeutic and diagnostic proposes. They allow for searching of small molecule inhibitors of binding interactions enabling modern drug discovery. Overall, the predicted Cp PPI networks form a valuable and versatile tool for researchers interested in Corynebacterium pseudotuberculosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-016-0346-4) contains supplementary material, which is available to authorized users.

Corynebacterium pseudotuberculosis Pneumonia in a Veterinary Student Infected During Laboratory Work

We present a case of Corynebacterium pseudotuberculosis pneumonia in a veterinary student, with molecular genetic evidence of acquisition during laboratory work, an observation relevant for laboratory personnel working with C pseudotuberculosis isolates. The patient was clinically cured with 14 months trimethoprim/sulfamethoxazole and rifampicin combination treatment.