Veterinary Microbiology
Date: 27 December 2013
Pages: 737-741

Published by: Elsevier

Published by

Elsevier
Short communication
Get rights and content

Short Communications
Virulence genes and antimicrobial susceptibility in Pasteurella multocida isolates from calves

Author links open overlay panelK. Katsuda, , , , O. Mikami
Access through your organizationPurchase PDFPatient Access

Abstract

A total of 378 isolates of Pasteurella multocida from clinically healthy and diseased calves were characterised for their susceptibility to 9 antimicrobial agents and screened by PCR for the presence of antimicrobial resistance genes and 22 genes virulence-associated, including capsule biosynthesis genes.
Of the 378 isolates, 102 (27.0%) were resistant to at least one of the 9 tested antimicrobial agents. Resistance to oxytetracycline (21.7%) was the most frequently observed phenotype among the isolates. The tet(H) gene were the primary determinant detected. The resistance rates for thiamphenicol, ampicillin, kanamycin and florfenicol were 13.2%, 5.8%, 9.0% and 0.5%, respectively. Cefazolin, ceftiofur, cefquinome and enrofloxacin were effective antimicrobial agents, with no resistant isolates emerging over the course of the investigation.
Most isolates were identified as capsular type A, only 6.3% belonged to capsular type D and no other capsular type was identified. Four of the virulence-associated genes (pfhA, tadD, tbpA and HAS) exhibited associations to the capsular type, and three (pfhA, tbpA and hgbB) were associated with the disease status of the animals. These virulence genes have been considered as epidemiological markers and are hypothesised to have a strong positive association with the outcome of disease in cattle.

Keywords

Pasteurella multocida
;
Antimicrobial susceptibility
;
Virulence gene
;
Cattle

Introduction

Bovine respiratory disease (BRD) is the most economically important disease among cattle. Many bacterial species are associated with the pneumonia seen in BRD. Pasteurella multocida is agents of BRD (Confer, 2009). Although improved vaccines are effective tools for the control of BRD, poor environmental conditions are one main reason for shortcoming in vaccination success. For therapy of clinical cases, antimicrobials remain effective tools for such bacterial infections. The increased prevalence of antimicrobial-resistant bacterial pathogens has become a major public health and animal health concern. Continuous regional monitoring of antimicrobial susceptibility is important for the selection of effective antimicrobial agents for treatment of bovine pneumonia.
P. multocida possesses various virulence factors, including capsule, lipopolysaccharide, fimbriae and adhesins, toxins, iron-regulated and iron acquisition proteins, sialic acid metabolism proteins, hyaluronidase and outer membrane proteins (Ewers et al., 2004, Harper et al., 2006). These virulence factors play important roles in the pathogenesis of P. multocida. Data on the antibiotic resistance profiles and virulence factors of P. multocida from cattle differing in disease status may yield a better understanding of pasteurellosis in cattle.
We investigated 378 isolates from clinically healthy and diseased calves to discover their distribution of capsular type, their phenotypic antimicrobial resistant profiles and the presence or absence of 17 virulence genes.

Organizational access

Get full-text access by signing in with your organisationAccess through your organization

Other access options

Purchase PDFPatient Access
Need help with access?

Section snippets

Bacterial isolates

A total of 378 P. multocida field isolates collected on the basis of one isolate per herd from cattle were investigated. Of the 378 isolates, 140 were from nasal swabs of clinically healthy cattle; the remaining 238 isolates were from lung lesions of BRD-affected cattle. The isolates were collected at our institute between 2009 and 2012 and originated from 30 different regions in Japan. All isolates were identified using API micro standardised strips (API 20NE; bioMérieux Japan Ltd., Tokyo,

Results

The MICs for 9 antimicrobial agents and the antimicrobial susceptibilities of the P. multocida isolates are listed in Table 1. Of the 378 isolates, 102 (27.0%) were resistant to at least one of the 9 antimicrobial agents, and the resistance rates ranged from 0.5% to 21.7%. Of the 102 resistant isolates, 49 isolates were resistant to 1 class of antimicrobial (15 isolates were resistant to ampicillin (ABPC), 32 isolates were resistant to oxytetracycline (OTC), 2 isolates were resistant to

Discussion

Monitoring the antimicrobial susceptibility trends of P. multocida is an important aid to veterinarians in selecting the most efficacious therapeutic agents. The results of the present study indicate that CEZ, CTF, CEQ, ERFX and FF are very active against the P. multocida isolates tested. On the basis of the MIC breakpoints of these agents, all but two of the isolates would be considered susceptible to these antimicrobial agents. OTC showed poor activity against P. multocida compared with other

Conflict of interest

All authors declare that there are no financial or other relationships that might lead to a conflict of interest.

Acknowledgements

We thank Natsuko Andou and Syuuko Sawajiri for excellent technical assistance in this study.

References (16)

There are more references available in the full text version of this article.
View full text

Cited by (66)

  • Research article
    Massacci F.R., …, Christensen H.I.
    Veterinary Microbiology • Volume 213 • 2018
  • Research article
    García-Alvarez A., …, Cid Vázquez M.D.
    Veterinary Microbiology • Volume 204 • 2017
  • Research article
    Sarangi L.N., …, Singh V.P.
    Comparative Immunology Microbiology and Infectious Diseases • Volume 38 • 2015
    Citation Excerpt:

    Filamentous haemagglutinins encoded by the pfhA gene play a major role in the initial colonization of the upper respiratory tract and the frequency of this gene varies greatly among strains of P. multocida. This gene has been reported to be an important epidemiological marker and correlated with occurrence of disease in cattle, swine and sheep [1,13,27,28]. Interestingly, we observed a very high prevalence of pfhA (95.4%) gene irrespective of its capsule type and origin of isolation.

  • Peng Z., …, Wu B.
    Archives of Microbiology • Volume 200 • 2018
  • Liu H., …, Xue Y.
    Irish Veterinary Journal • Volume 70 • 2017 • Article 2
  • Cameron A., McAllister T.A.
    Journal of Animal Science and Biotechnology • Volume 7 • 2016 • Article 68
View all citing articles on Scopus

Metrics

Citations

  • Citation Indexes66

Captures

  • Mendeley Readers70
View details
Copyright © 2013 Elsevier B.V. All rights reserved.