Evaluation of changes in antimicrobial susceptibility patterns of Pasteurella multocida subsp multocida isolates from pigs in Spain in 1987-1988 and 2003-2004.
OBJECTIVE
To determine the susceptibility of strains of Pasteurella multocida subsp multocida isolated from lung specimens of pigs with pneumonia to 20 antimicrobials and to evaluate the emergence of resistance to those antimicrobials in Spain during the past 2 decades.


METHODS
63 isolates recovered from 1987 to 1988 and 132 isolates recovered from 2003 to 2004.


METHODS
A broth microdilution method was used to determine minimal inhibitory concentration (MIC) range and values for MIC50 and MIC90. Resistance of a strain to an antimicrobial agent was determined by use of the breakpoint value when available.


RESULTS
Isolates were generally susceptible to penicillin, ampicillin, ceftiofur, gentamicin, apramycin, neomycin, spectinomycin, chlortetracycline, erythromycin, tilmicosin, enrofloxacin, and florfenicol, and most isolates were resistant to clindamycin, tylosin tartrate, and tiamulin regardless of the time period. A substantial increase in resistance to sulfa-chlorpiridazine, sulfadimethoxine, sulfathiazole, and trimethoprim-sulfamethoxazole was observed, and a minor increase in resistance to oxytetracycline was also detected. Several multiresistance patterns were observed, most frequently among isolates recovered in the 2003 to 2004 interval.


CONCLUSIONS
Ceftiofur, florfenicol, and enrofloxacin are recommended for treatment of infections caused by P multocida subsp multocida in Spain. Increased frequency of resistance to oxytetracycline and sulfonamide drugs may be a contraindication for their use.
Department of Animal Health, Microbiology and Immunology Section, Faculty of Veterinary Medicine, University of León, 24007-León, Spain.
Yanedt A Vera
YA
Lizarazo
Elías F Rodríguez
EF
Ferri
A Judith Martín
AJ
de la Fuente
César B Gutiérrez
CB
Martín
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D008826:Microbial Sensitivity Tests; D016979:Pasteurella multocida / Q000187:drug effects* / Q000302:isolation & purification; D013449:Sulfonamides / Q000494:pharmacology; D013552:Swine / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D013449:Sulfonamides