CHARACTERISATION, PATHOGENICITY AND ANTIBIOTIC RESISTANCE OF MYCOPLASMAS INVOLVED IN VULVOVAGINITIS IN GOATS

ABSTRACT

Vulvovaginitis is an inflammation of the vulva and vagina caused by bacteria, fungi, viruses, parasites and allergy. The condition results in reduction in mating ability, infertility, abortion and death of the affected animals with resultant economic loss to the livestock industry. Although mycoplasmas have been isolated from cases of vulvovaginitis, their role as sole causative agents and in the pathogenicity of the disease have not been investigated in goats in Nigeria. The aim of this study was to characterise mycoplasma isolates from cases of vulvovaginitis and also and determine the pathogenicity of mycoplasma-induced vulvovaginitis in goats. Two hundred and twenty-one vaginal swabs were obtained from identified cases of vulvovaginitis in goats aged 8- 11 months from markets in and around Lagos metropolis. Samples were analyzed bacteriologically and mycoplasmotologically. Mycoplasmas were identified biochemically using standard procedures and conventional polymerase chain reaction with specific primers. Antisera raised in rabbits using 0.5ml of 4.0 x107 CFU/ml of selected Mycoplasma species including M. bovis, M. capri, M. capricolum and M. arginini were used to group the mycoplasmas serologically by growth inhibition method. Sensitivity of the isolated Mycoplasmas and other bacteria to aminoglycosides, fluoroquinolones, cephalosporins and nitrofurans was carried out. Pathogenicity of the isolated M. bovis, M. capri, M. capricolum and M. arginini was evaluated using 2ml inoculum containing 4.0 x 10 7 CFU/ml of each isolate per vulva to reproduce vulvovaginitis over a six week experimental period. Four goats were used for each experimental group and the control group. Animals were observed for symptoms of vulvovaginitis such as hyperemia, vulva swelling and vaginal mucus discharges. Post-mortem gross and histopathological examination was carried out and findings reported. Other data were analysed using descriptive statistics. Two hundred and fifty-seven bacterial isolates were recovered from the 221 field samples as follows: Mycoplasma capricolum (1.6%), Mycoplasma arginini (1.6%), Mycoplasma capri (1.2%), Mycoplasma bovis (0.78%), Ureaplasma species (1.2%), Acholeoplasma species (0.8%). Other bacteria were Escherichia coli (35.4%), Streptococcus species (29.2%) and Staphylococcus species (28.4%). Mycoplasma isolates were confirmed with the production of specific 280bp bands. Isolated Mycoplasma species and other bacteria were sensitive to ciprofloxacin and nitrofurantoin. Six different combinations of antibiotic resistant patterns were observed with amoxicillin, norfloxacin and ampicillin having the highest level of resistance (100.0%) and nitrofurantoin the least (33.0%). Clinical symptoms, which included hyperemia, swollen vulva, vaginal mucus discharges with pyrexia (38.9 – 39.60 C), were first observed in the M. bovis- infected group on day three, ten and thirteen. Mortality was recorded on days 30, 33, 38 and 41 post- inoculation in the M. bovis, M. capricolum, M. arginini and M. capri- infected groups, respectively. M. bovis produced the most severe lesions marked by lymphoid necrosis of the vulva tissue, diffuse hyperaemia in the lung alveolar septa and massive alveolar infiltration with neutrophils while the mildest lesions were observed in the M. arginine-infected group. Vulvovaginitis was reproduced in goats with all the Mycoplasma species as the major infective agent and Mycoplasma bovis as the most pathogenic. Ciprofloxacin and nitrofurantoin were the most effective antibiotics against Mycoplasmas and other bacteria isolated.