EVALUATION OF ANTIMICROBIAL TREATMENT OUTCOMES IN NATURAL MCCP OUTBREAKS AND THEIR RELATIONSHIP WITH CLINICAL MANIFESTATIONS: A CROSS-SECTIONAL STUDY

Abstract

Background: Contagious caprine pleuropneumonia is a highly contagious and economically devastating disease of sheep and goats caused by Mycoplasma capricolum subsp. capripneumoniae. The disease remains endemic in many developing regions, where limitations in early diagnosis and inappropriate antibiotic use complicate control efforts. Overlapping clinical signs with other respiratory infections and the increasing emergence of antimicrobial resistance further highlight the need for region-specific clinical and therapeutic evidence to support effective disease management.

Objective: The study aimed to evaluate the clinical manifestations associated with contagious caprine pleuropneumonia and to determine the antibiotic susceptibility profile of Mycoplasma capricolum subsp. capripneumoniae isolates recovered from naturally infected sheep and goats.

Methods: A cross-sectional study was conducted in four talukas of Umerkot District, Sindh, Pakistan. A total of 1,600 samples, including nasal, throat, and vaginal swabs, were collected from clinically suspected sheep and goats. Samples were cultured on Modified Hayflick medium for isolation of Mycoplasma species, followed by biochemical confirmation. Clinical and epidemiological data were recorded using a structured questionnaire. Antibiotic susceptibility testing was performed using the disc diffusion method against nine commonly used antimicrobials. Statistical analyses included Chi-square tests, binary logistic regression, contingency coefficient analysis, and one-way ANOVA.

Results: Out of the examined animals, 402 were clinically positive for contagious caprine pleuropneumonia. Elevated body temperature was observed in 90.05% of cases and nasal discharge in 86.56%, both showing strong associations with disease severity. Cough (81.09%) and dyspnea (64.17%) demonstrated moderate associations, while anorexia (60.69%) and weakness (57.46%) showed weaker correlations. Antibiotic susceptibility testing revealed the highest mean zones of inhibition for enrofloxacin (19.14 ± 1.09 mm), followed by ciprofloxacin (16.02 ± 0.83 mm) and gentamicin (13.58 ± 0.71 mm). Moderate inhibitory responses were recorded for ampicillin, tylosin, and oxytetracycline, whereas complete resistance was observed against cloxacillin and ceftiofur sodium.

Conclusion: Fever and nasal discharge emerged as the most reliable clinical indicators for early field diagnosis of contagious caprine pleuropneumonia. Fluoroquinolones and gentamicin demonstrated superior in-vitro efficacy against Mycoplasma capricolum subsp. capripneumoniae, while β-lactam antibiotics were ineffective. These findings emphasize the importance of evidence-based antibiotic selection and rational antimicrobial use to improve disease control and limit the progression of antimicrobial resistance in small ruminant production systems.