Comparison of the in vitro susceptibility of rodent isolates of Pseudomonas aeruginosa and Pasteurella pneumotropica to enrofloxacin

• Published in: Journal of veterinary diagnostic investigation 2007-09, Vol.19 (5), p.557-560
• Main Authors: Sasaki, H, Kawamoto, E, Kunita, S, Yagami, K
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; antibiotic resistance; bacterial infections; dosage; Enrofloxacin; Fluoroquinolones - pharmacology; in vitro culture; isolation; Mice; microbial genetics; Microbial Sensitivity Tests; minimum inhibitory concentration; Mutation; Pasteurella Infections - drug therapy; Pasteurella Infections - microbiology; Pasteurella pneumotropica; Pasteurella pneumotropica - drug effects; Pasteurella pneumotropica - genetics; Pasteurella pneumotropica - isolation & purification; pasteurellosis; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - isolation & purification; Pseudomonas Infections - drug therapy; Pseudomonas Infections - microbiology; Rats; Rodent Diseases - drug therapy; Rodent Diseases - microbiology; strain differences; strains
• ISSN: 1040-6387; 1943-4936
• DOI: 10.1177/104063870701900517

Correspondence: 1 Corresponding Author: Hiraku Sasaki, Animal Research Center, Tokyo Medical University, Shinjuku, Tokyo 160-8402, Japan, e-mail: h-sasaki{at}tokyo-med.ac.jp The objectives of this study were to determine and compare the in vitro enrofloxacin susceptibility of 94 Pseudomonas aeruginosa isolates obtained from enrofloxacin-treated and untreated mice and that of 40 Pasteurella pneumotropica strains and also to assess the efficacy and effects of enrofloxacin treatment of laboratory mice. The minimum inhibitory concentrations (MICs) of enrofloxacin against all the Ps. aeruginosa isolates were in the range of 1 to 4 µg/ml, whereas those against all the P. pneumotropica strains were less than 0.5 µg/ml. The mutation frequency in 54% of the Ps. aeruginosa isolates on treatment with enrofloxacin ranged from 10 –6 to 10 –8 ; however, none of the P. pneumotropica strains could grow on medium containing more than 3 µg/ml enrofloxacin. Comparison of in vitro enrofloxacin susceptibilities suggested that enrofloxacin was effective for eliminating P. pneumotropica but not for eliminating Ps. aeruginosa for which the MIC of enrofloxacin was more than 1 µg/ml. These results indicated that the enrofloxacin susceptibility of P. pneumotropica was higher than that of Ps. aeruginosa, and that the enrofloxacin treatment might not affect the susceptibility of Ps. aeruginosa . Key Words: Enrofloxacin • minimum inhibitory concentration • mutation frequency • Pasteurella pneumotropica • Pseudomonas aeruginosa