Serotypes, Antimicrobial Susceptibility, and Minimal Inhibitory Concentrations of Actionbacillus pleuropneumoniae Isolated from Slaughter Pigs in Taiwan (2002-2007)

Abstract

ABSTRACT. In total, 211 isolates of A. pleuropneumoniae were collected from pigs with hemorrhagic pneumonia at slaughterhouses during [2002][2003][2004][2005][2006][2007]. Serotypes, antimicrobial susceptibility and minimum inhibitory concentration (MIC) values were determined for each isolate of A. pleuropneumoniae to 10 antimicrobial agents. Serovar 1 of A. pleuropneumoniae was predominant in Taiwan in 138 of the 211 isolates, followed by serovars 2 and 5. More than 90% of collected isolates were sensitive to ceftiofur, cephalothin, and chloramphenical. However, lincospectin and gentamicin were relatively less susceptible with sensitivities of only 2.4 and 5.7%, respectively. Additionally, ceftiofur had the highest in vitro activity with an MIC 50 of 2.2 µg/ml, followed by cephalothin (2.7 µg/ml) and chloramphenicol (7.9 µg/ ml). Lincospectin had the least activity with MIC 50 and MIC 90 values of 73.9 and 114.5 µg/ml, respectively. The data indicate that ceftiofur and cephalothin were extremely active against A. pleuropneumoniae and with minimum MIC values. These drugs are suitable for controlling and treating hemorrhagic pleuropneumonia outbreaks in swine.KEY WORDS: Actinobacillus pleuropneumoniae, antimicrobial susceptibility, minimum inhibitory concentration, serotype, swine.J. Vet. Med. Sci. 73(2): 205-208, 2011 Porcine necrotizing hemorrhagic pleuropneumonia caused by Actinobacillus pleuropneumoniae is one of the most costly respiratory diseases in swine industries. The acute type of this disease is highly contagious and has a high mortality rate, it is economically important for pig producers [15].Fifteen serovars of A. pleuropneumoniae have been recognized [2]. The distributions of serovars differ among countries [1,8,11]. Serovars 1, 2, 3, 5, 7, and 8 of A. pleuropneumoniae have been isolated and confirmed in Taiwan [3,6,9,10]; serovar 1 was the predominate isolate [5].Administering antimicrobial agents is the most common and effective strategy employed for controlling and treating this lethal disease in the field. Several antimicrobial agents have been employed clinically. Since antimicrobial susceptibility can change over time in the same area [8], an effective treatment using antimicrobial agents against A. pleuropneumoniae in the field requires detailed information about the antimicrobial activities of antimicrobial agents. This study investigates the serotypes of A. pleuropneumoniae isolates and in vitro activity of antimicrobial agents against A. pleuropneumoniae isolates collected from slaughterhouse pigs in Taiwan. MATERIALS AND METHODSA. pleuropneumoniae isolation and serotyping: In total, 685 lung specimens with typical hemorrhagic necrotizing pneumonia obtained from 5 pig slaughterhouses were collected during [2002][2003][2004][2005][2006][2007]. All isolates were cultured on tryptic soy blood agar plates (Difco Lab., Detroit, MI, U.S.A.) with 1% nicotinamide adenine dinucleotide (SigmaAldrich, St. Louis, MO, U.S.A.). Plates were incubated for 24 hr at 37°C under 5% CO 2 . Isolates were ...

Antimicrobial susceptibility of Actinobacillus pleuropneumoniae strains isolated from pig's clinical samples in Serbia

“…Similar results were obtained in other studies for florfenicol (14,32), ceftiofur/cefotaxime (19) and enrofloxacin (24). A high susceptibility to lincospectin correlates with the observed susceptibility of 95% in neighboring Croatia (15), but differs from the results obtained in Taiwan where only 2.4% of the 211 investigated strains were susceptible to this antibiotic (31). High rates of susceptibility of 91% were observed for ampicillin and amoxicillin, which is in agreement with the reports by Matter and Kucerova (19,22).…”

“…On the other hand, these results differ from the results of Vanni (30) who found 69% and 82% resistance to ampicillin and amoxicillin, respectively. The susceptibility to gentamicin in our study was 77%, which is much higher than susceptibil- ity rates of 5.7% and 43% published by other authors (26,31). In our study the highest resistance rates were determined to tetracycline (34%) and streptomycin (31%).…”

Antimicrobial Susceptibilities and Resistance Genes of Canadian Isolates ofActinobacillus pleuropneumoniae

“…A wide variety of antimicrobial agents have been suggested for treating this disease including b-lactams (amoxicillin, penicillin, ampicillin, and ceftiofur), tetracyclines (tetracycline and doxycycline), florfenicol, trimethoprim/sulfamethoxazole, tiamulin, lincomycin/spectinomycin, fluoroquinolones (danofloxacin and enrofloxacin), and gentamicin. 49 Various antimicrobial resistance patterns have been observed in several studies among strains from different geographical regions, 10,17,23,32 serovars, 3,53,54 and also over time. 22,37,48 While most isolates are reported to be susceptible toward fluoroquinolones, ceftiofur, and florfenicol, resistances toward ampicillin, tetracycline, and other antimicrobials are emerging (reviewed by Aarestrup et al 1 ).…”

“…Previous studies reported similar susceptibility data for A. pleuropneumoniae for florfenicol 22,34,54 and ceftiofur. 2,10,31,34,42,44,53,54 However, a recent study from Czech Republic reported for the first time florfenicol resistance at a low degree (0.8%). 32 The presence of the floR gene was detected by PCR in all their resistant isolates.…”

Recombinant ApxIV protein enhances protective efficacy againstActinobacillus pleuropneumoniaein mice and pigs

“…In Taiwan, serovar 1 is the most common serovar isolated, accounting for 65·4% of cases, followed by serovars 2 and 5, with 34·6% (Yang et al . ). As a comparison, in Japan, serovars 2 and 5 are the most commonly isolated, and in Canada, serovars 5 and 7 (Morioka et al .…”