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In vitro activity of oral antimicrobial agents against clinical isolates of Pasteurella multocida
J E Mortensen1, O Giger, G L Rodgers
1Department of Pediatrics, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Abstract:
Pasteurella multocida causes a wide variety of infections and is the most common localized soft tissue infection after animal bite injuries. Penicillin or amoxicillin has been considered agent of choice for therapy. Reported beta-lactamase production by some isolates, the therapeutic dilemma of the penicillin allergic patient, and the polymicrobial nature of some infections led to this study of alternate antimicrobial agents. The in vitro activity of ampicillin, amoxicillin/clavulanate, cefprozil, cefuroxime, erythromycin, clarithromycin, trimethoprim/sulfamethoxazole, ciprofloxacin, and tetracycline were compared to penicillin against 73 geographically diverse isolates of P. multocida from human infections collected since 1991. MIC90 (microgram/mL) were as follows: penicillin < or = 0.06; ampicillin < or = 0.5; amoxicillin/clavulanate < or = 0.5; cefaclor 1.0; cefprozil 1.0; cefpodoxime 0.06; cephalothin 2.5; cefuroxime < or = 0.25; erythromycin 2.0; azithromycin 1.0; clarithromycin 4.0; trimethoprim/sulfamethoxazole < or = 0.5/9.5; ciprofloxacin < or 0.25; tetracycline < or = 2.0. No beta-lactamase producing isolates were found in this study. This in vitro study has identified alternate oral agents to penicillins that may be appropriate for therapy of P. multocida infections.
Insights
Penicillin remains effective against Pasteurella multocida infections, with no beta-lactamase production found. Several alternative oral antibiotics, including cefpodoxime and ciprofloxacin, also show strong in vitro activity.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Pasteurella multocida is a common cause of soft tissue infections following animal bites.
- Penicillin and amoxicillin are traditional treatments, but concerns exist regarding beta-lactamase production and penicillin allergies.
- The need for alternative antimicrobial agents is driven by potential resistance and complex infections.
Purpose of the Study:
- To evaluate the in vitro antimicrobial activity of various oral agents against Pasteurella multocida.
- To identify potential alternatives to penicillin for treating P. multocida infections.
Main Methods:
- Susceptibility testing was performed on 73 geographically diverse P. multocida isolates from human infections.
- Minimum inhibitory concentration (MIC90) values were determined for penicillin, ampicillin, amoxicillin/clavulanate, cefaclor, cefprozil, cefpodoxime, cephalothin, cefuroxime, erythromycin, azithromycin, clarithromycin, trimethoprim/sulfamethoxazole, ciprofloxacin, and tetracycline.
Main Results:
- All tested P. multocida isolates were susceptible to penicillin (MIC90 ≤ 0.06 µg/mL).
- No beta-lactamase producing isolates were detected in this study.
- Several alternative agents demonstrated potent in vitro activity, including cefpodoxime (MIC90 = 0.06 µg/mL), ciprofloxacin (MIC90 < 0.25 µg/mL), and cefuroxime (MIC90 ≤ 0.25 µg/mL).
Conclusions:
- Penicillin remains a highly effective agent against P. multocida based on this in vitro data.
- Cefpodoxime, ciprofloxacin, and cefuroxime are promising oral alternatives for P. multocida infections.
- Further clinical studies are warranted to confirm the efficacy of these alternative agents in patient treatment.