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Antibiotic susceptibilities of human isolates of Pasteurella multocida
Abstract:
Seventeen human strains of Pasteurella multocida, biochemically similar to, if not identical with, isolates of animal origins, were tested for susceptibility to 16 antimicrobial agents utilizing a microtiter broth dilution technique. Ten of these isolates were also tested against 11 antibiotics by disk diffusion. The most active drugs with respect to the median minimal inhibitory concentration (micrograms per milliliter) were tetracycline (0.09), penicillin G (0.78), ampicillin (0.78), carbenicillin (1.56), cephalothin (1.56), and chloramphenicol (1.56). With the exception of tetracycline, the median minimal inhibitory concentration and minimal bactericidal concentration values were equal or differed by no more than a factor of two. The semisynthetic penicillins clindamycin, erythromycin, and aminoglycosides had relatively low activities, suggesting that these agents would be poor choices for the treatment of P. multocida infections.
Insights
Tetracycline, penicillin G, and ampicillin show high activity against human Pasteurella multocida strains. Other antibiotics like clindamycin and erythromycin are less effective for treating these infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Pasteurella multocida is a bacterium that can cause infections in humans, often resembling those seen in animals.
- Understanding antimicrobial susceptibility is crucial for effective treatment of Pasteurella multocida infections.
Purpose of the Study:
- To evaluate the in vitro susceptibility of human Pasteurella multocida isolates to various antimicrobial agents.
- To identify the most effective antibiotics for treating infections caused by this pathogen.
Main Methods:
- Seventeen human strains of Pasteurella multocida were tested.
- Microtiter broth dilution technique was used to determine minimal inhibitory concentrations (MICs) for 16 antimicrobial agents.
- Disk diffusion assays were performed for 11 antibiotics on ten isolates.
Main Results:
- Tetracycline, penicillin G, ampicillin, carbenicillin, cephalothin, and chloramphenicol demonstrated significant antimicrobial activity.
- Median MIC values were lowest for tetracycline (0.09 µg/mL), penicillin G (0.78 µg/mL), and ampicillin (0.78 µg/mL).
- Semisynthetic penicillins (clindamycin), erythromycin, and aminoglycosides exhibited limited efficacy against these isolates.
Conclusions:
- Tetracycline, penicillin G, and ampicillin are highly effective against human Pasteurella multocida.
- Clindamycin, erythromycin, and aminoglycosides are not recommended for treating P. multocida infections due to low activity.
- Findings provide guidance for selecting appropriate antimicrobial therapy for human Pasteurella multocida infections.