CHARACTERIZATION OF STENOTROPHOMONAS MALTOPHILIA AND STENOTROPHOMONAS PAVANII ISOLATED FROM DISEASED COMPANION ANIMALS, HORSES AND AN ORANGUTAN

Stenotrophomonas (S.) maltophilia is ubiquitous in the environment and is an archetypical opportunistic pathogen. S. maltophilia has become important during the last decades as a nosocomial pathogen particularly among immunosuppressed individuals. While studies on S. maltophilia in humans have been widely documented, there is still little information on infections, carriage and role of the pathogen in animals. S. maltophilia is thought to be part of the physiological microbiota in certain reptiles but has been rarely associated with other animals. The aim of the present study was to investigate the genetic relatedness and the antimicrobial resistance profiles of a collection of S. maltophilia strains from dogs (n=6), cats (n=4), a dwarf rabbit, horses (n=5), and a zoo-kept orangutan as well as a canine S. pavanii isolate. All strains were obtained during routine diagnostic activities and confirmed as S. maltophilia or S. pavanii by MALDI-TOF mass spectrometry and sequence analyses of the 16S rRNA and gyrB genes. Antimicrobial susceptibility testing was performed and resistance genes as well as genes responsible for biofilm formation were detected by PCR.

All strains were susceptible to minocycline, two strains were resistant to trimethoprim + sulfamethoxazole and one strain was resistant to trimethoprim + sulfamethoxazole as well as to levofloxacin. The resistance gene L1 coding for a metallo-β-lactamase that degrades penicillins, cephalosporins, and carbapenems, was identified in all strains.

The conducted study represents the first comprehensive investigation on characteristics of S. maltophilia and closely related S. pavanii from diseased companion animals, horses and a zoo-kept orangutan in Austria. The exact role of animals in the epidemiology of S. maltophilia and related species needs to be determined in studies that include human strains.