In vitro susceptibility of Haemophilus somnus to 33 antimicrobial agents

Area of Science:

• Veterinary Microbiology
• Antimicrobial Resistance
• Bacterial Pathogenesis

Background:

• Haemophilus somnus is a significant pathogen in livestock, causing various diseases.
• Understanding antimicrobial susceptibility is crucial for effective treatment and disease management.
• Limited data exists on the comprehensive antimicrobial profiles of H. somnus isolates.

Purpose of the Study:

• To determine the minimal inhibitory concentrations (MICs) of 33 antimicrobial agents against Haemophilus somnus.
• To identify antimicrobial agents effective against H. somnus.
• To assess the prevalence of resistance to specific antimicrobials in H. somnus strains.

Main Methods:

• Agar dilution method was employed to test 33 antimicrobial agents.
• Multiple strains of Haemophilus somnus were utilized in the study.
• MIC values were systematically recorded for each antimicrobial agent.

Main Results:

• Haemophilus somnus strains exhibited high susceptibility to penicillin G, ampicillin, colistin, and novobiocin.
• In contrast, strains were not susceptible to spiramicin and sulfadimethoxine.
• The study identified streptomycin-resistant strains of H. somnus.

Conclusions:

• Penicillin G, ampicillin, colistin, and novobiocin are potential therapeutic options for H. somnus infections.
• Spiramicin and sulfadimethoxine are unlikely to be effective treatments for H. somnus.
• The emergence of streptomycin resistance in H. somnus necessitates careful antimicrobial selection.