Antimicrobial Susceptibility of Bordetella bronchiseptica Isolates from Swine and Companion Animals and Detection of Resistance Genes

Abstract

Bordetella bronchiseptica causes infections of the respiratory tract in swine and other mammals and is a precursor for secondary infections with Pasteurella multocida. Treatment of B. bronchiseptica infections is conducted primarily with antimicrobial agents. Therefore it is essential to get an overview of the susceptibility status of these bacteria. The aim of this study was to comparatively analyse broth microdilution susceptibility testing according to CLSI recommendations with an incubation time of 16 to 20 hours and a longer incubation time of 24 hours, as recently proposed to obtain more homogenous MICs. Susceptibility testing against a panel of 22 antimicrobial agents and two fixed combinations was performed with 107 porcine isolates from different farms and regions in Germany and 43 isolates obtained from companion animals in Germany and other European countries. Isolates with increased MICs were investigated by PCR assays for the presence of resistance genes. For ampicillin, all 107 porcine isolates were classified as resistant, whereas only a single isolate was resistant to florfenicol. All isolates obtained from companion animals showed elevated MICs for β-lactam antibiotics and demonstrated an overall low susceptibility to cephalosporines. Extension of the incubation time resulted in 1–2 dilution steps higher MIC50 values of porcine isolates for seven antimicrobial agents tested, while isolates from companion animals exhibited twofold higher MIC50/90 values only for tetracycline and cefotaxime. For three antimicrobial agents, lower MIC50 and MIC90 values were detected for both, porcine and companion animal isolates. Among the 150 isolates tested, the resistance genes bla BOR-1 (n = 147), bla OXA-2, (n = 4), strA and strB (n = 17), sul1 (n = 10), sul2 (n = 73), dfrA7 (n = 3) and tet(A) (n = 8) were detected and a plasmid localisation was identified for several of the resistance genes.

Survey of antimicrobial susceptibility of bacterial pathogens isolated from dogs and cats with respiratory tract infections in Europe: ComPath results

“…In another study on companion animal isolates including dogs and cats (Prüller et al . ), similar MIC 50/90 values were observed with the exception of lower MIC 50/90 for trimethoprim/sulfamethoxazole (0·06/2 μ g ml −1 ) and lower MIC 90 for doxycycline and tetracycline (0·25–0·5 μ g ml −1 ). However, two other studies on isolates almost entirely obtained from dogs and cats reported similar enrofloxacin MIC 90 values as our work (Speakman et al .…”

“…Prüller et al . ). Despite their importance, standardized, ongoing RTI surveys are uncommon and, hence, only limited information is available about antimicrobial susceptibility of RTI pathogens of dogs and cats.…”

The First Siphoviridae Family Bacteriophages Infecting Bordetella bronchiseptica Isolated from Environment

“…B. bronchiseptica bacteriophage examination, however, is important from several aspects. For many multiple resistant bacteria, bacteriophages can be an alternative to conventional antibiotics [14], and B. bronchiseptica possesses innate or acquired antibiotic resistance to β-lactams, macrolides, tetracyclines, sulphonamides, and aminoglycosides, usually used for the treatment of animals with respiratory infections [15]. Furthermore, phage genomes can be new sources of genes for lytic enzymes, i.e., enzybiotics, as well as other valuable proteins [16].…”

Bacterial Diseases

“…Antimicrobial susceptibility profiles have recently been published for B. bronchiseptica isolates from swine and companion animals [36]. B. bronchiseptica is generally resistant to macrolide antibiotics and cephalosporins and often carries b-lactamase resistance genes.…”