Aerobic and anaerobic bacterial isolates from horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes.

This research seeks to understand the frequency and types of aerobic and anaerobic bacterial infections in horses with pneumonia or pleuropneumonia. The study further discusses the survival rate of these horses and the antimicrobial susceptibility patterns of the isolated aerobic bacteria.

Objective of the Study

The study set out to investigate the occurrence of aerobic and anaerobic bacterial infections in horses that were suffering from pneumonia or pleuropneumonia. Furthermore, the research investigated the antimicrobial susceptibility patterns of aerobic bacteria.

Sample Size and Results

• The study involved a considerable sample size of 327 horses, which solidifies the credibility of the collected data. Among these, pneumonia or pleuropneumonia was diagnosed.
• From the total sample, 75% of the horses survived the ordeal, while 20% were euthanatized, and 5% unfortunately died.
• Interestingly, tracheobronchial aspirates or pleural fluid specimens drawn from 25 of these horses did not show any bacterial growth, leaving 302 horses for further investigation.
• From the latter, aerobic organisms were isolated from 221 horses, while only 6 had anaerobic bacteria isolated. This contrast in numbers suggest that aerobic organisms are more common in such conditions than their anaerobic counterparts are.
• The remaining 75 horses were found to have mixed infections of both bacterial types.

Bacterial Types and Survival Rate

• The survival rate for horses with only aerobic bacteria was found to be twice that of those with anaerobic bacteria, suggesting how each bacteria type impacts the severity of the disease.
• Among the aerobic bacterial species, beta-Streptococcus spp, Pasteurella spp, Escherichia coli, and Enterobacter spp were most frequently isolated.
• For the anaerobic species, Bacteroides spp, and Clostridium spp were prevalent.

Conclusion

From this study, it became apparent that both aerobic and anaerobic bacteria are common among horses with pneumonia or pleuropneumonia. However, those with aerobic bacteria had a higher survival rate, suggesting a potentially more adverse effect of anaerobic bacteria. These findings could be critical for developing effective treatment strategies for such horses.