Molecular characterization of Rhodococcus equi isolates in equines.

AIM: The aim was to determine the occurrence of Rhodococcus equi in equines and their environment in Jammu (R.S. Pura, Katra), molecular characterization and to determine the antibiotic resistance pattern of R. equi. MATERIALS AND METHODS: A total of 96 nasopharyngeal swab samples were collected from equines. The organism was isolated on Columbia nalidixic acid agar containing 5% sheep blood as well as on sheep blood agar and was later confirmed by cultural characteristics and biochemical tests. Molecular detection of R. equi isolates was done by 16S rRNA gene amplification followed by virulence associated protein A (Vap A) gene amplification. Antibiogram was performed against five antibiotics, viz., amoxicillin, penicillin G, streptomycin, rifampicin, and methicillin. RESULTS: During the study, 9 R. equi isolates were identified on the basis of cultural and biochemical tests. In the polymerase chain reaction based detection, 3 among the 9 rhodococcal isolates were positive for species-specific 16S rRNA gene and revealed amplicon of 450 bp for confirmation of 16S rRNA gene. None of the sample was found positive for Vap A gene. In antibiogram, R. equi isolates were found sensitive for amoxicillin, while some isolates were also found resistant to the most conventional antibiotic penicillin G. CONCLUSION: From this study, it was concluded that R. equi infection is prevalent in equines in Jammu region of India and the indiscriminate use of the antibiotics is leading toward the development of resistant strains of R. equi.

Molecular characterization of virulence genes of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus in equines.

AIM: The aim was to determine the occurrence of streptococci in equines in Jammu (R. S. Pura, Katra), characterization of Streptococci equi subsp. equi and Streptococcus equi subsp. zooepidemicus with respect to their virulence traits and to determine antibiotic sensitivity pattern of virulent Streptococcus isolates. MATERIALS AND METHODS: A total of 96 samples were collected from both clinically affected animals (exhibiting signs of respiratory tract disease) and apparently healthy animals and were sent to laboratory. The organisms were isolated on Columbia nalidixic acid agar containing 5% sheep blood as well as on sheep blood agar and confirmed by cultural characteristics and biochemical tests. Molecular detection of Streptococcus was done directly from cultures using sodA and seM gene-based polymerase chain reaction (PCR). Antibiogram was performed against five antibiotics such as amoxicillin, penicillin G, streptomycin, rifampicin, and methicillin. RESULTS: During this study, a total 40 streptococcal isolates were obtained out of which 2 isolates were of S. equi subsp. equi, 12 isolates were from S. equi subsp. zooepidemicus. In the PCR-based detection, we revealed amplicons of 235 bp and 679 bp for confirmation of sodA and seM gene, respectively. In antibiogram, two isolates of S. equi subsp. equi were found resistant to penicillin G, and all other isolates were found sensitive to amoxicillin and streptomycin. CONCLUSION: The majority of streptococcal infections was due to S. equi subsp. Zooepidemicus, and thus was recognized as a potential pathogen of diseases of equines besides S. equi subsp. equi.

Non-specificity of primers used for PCR based serogrouping of Dichelobacter nodosus and identification of a novel D. nodosus strain.

The present study records the first case of non-specificity of typing primers developed by Dhungyel et al. A strain of Dichelobacter nodosus (JKS-20G) isolated from ovine footrot in Kashmir, India, showed specificity for serogroup C and G primers. The fimA sequence of the strain turned out to be closer to serogroup G than C. The nucleotide sequence showed maximum homology of 92% with that of serotype G1 strain 238 and 95% with partial sequence available for serotype G2 strain VCS 1004. However, the deduced amino acid sequence of the fimbrial subunit gene of JKS-20G differed from strain 238 by 16 amino acids and by four amino acids from that of partial sequence of strain VCS 1004. This variation indicates towards declaring this isolate as a new serotype (G3) but just insufficient to classify this into a new serogroup. Some of the amino acid substitutions were located within three hypervariable regions a characteristic of different serogroups. However, to ascertain whether this isolate deserves a new serotype status, there is a need to go for antigenic characterisation of this isolate using the tube and cross tube agglutination test.

Predominance of rotavirus genotype G6P[11] in diarrhoeic lambs.

Out of 500 faecal samples from lambs with diarrhoea in Jammu and Kashmir, India, 66 (13.2%) were positive for group A rotavirus (GARV) by the latex agglutination test (LAT). Electropherotyping by RNA-polyacrylamide gel electrophoresis revealed the typical GARV 4-2-3-2 migration pattern in 49/66 (74.2%) samples. Fifty-two samples (10.4%) were positive by reverse transcription-PCR. G6 was the predominant G genotype (25/52; 48.07%), followed by G10 (19/52; 36.54%) whereas, the predominant P genotype was P[11] (46/52; 88.46%). G6P[11] is the prevalent strain of group A rotavirus in sheep in Jammu and Kashmir, India.

Ovine rotaviruses.

Rotavirus has been recognized as a predominant cause of acute diarrhea in young animals and humans. Rotavirus has segmented genome composed of 11 segments of double stranded RNA. The virus has a triple layered protein shell consisting of a core, an inner capsid and an outer capsid. The inner capsid protein is responsible for group specificity and based on it rotaviruses are classified into seven groups. Ovine rotavirus strains have only been identified into two serogroups (A and B). The two outer capsid proteins (VP7 and VP4) are responsible for G and P typing of rotavirus, respectively. Although rotavirus has been frequently reported in many animal species, data regarding ovine rotavirus strains is very scanty and limited. Only a few ovine rotaviruses have been isolated and characterized so far. Recently, the G and P types circulating in ovines have been identified. The ovine rotavirus strain NT isolated from a diarrheic lamb in China is being considered as a promising vaccine candidate for human infants.