Stenotrophomonas maltophilia as a causative agent of bacterial infections in the horse: two clinical cases

Abstract

ZusammenfassungStenotrophomonas maltophilia ist ein gramnegatives Stäbchen, das in der Humanmedizin seit Längerem als primäres Pathogen bekannt und wegen seiner natürlichen Resistenz gegenüber zahlreichen Antibiotika gefürchtet ist. In der veterinärmedizinischen Literatur wurde es kürzlich mit chronischen Atemwegserkrankungen des Pferdes in Zusammenhang gebracht (Albini et al., 2009 Stenotrophomonas maltophilia, a gram -negative rod, is an important emerging nosocomial agent and primary pathogen in human patients. Treatment has proven to be difficult due to natural resistances against a wide range of common antibiotics. Recently, Albini and co-workers (2009) described an association between chronic respiratory diseases in horses and infections with Stenotrophomonas maltophilia. To our current knowledge, no reports about Stenotrophomonas maltophilia as a causative agent of non -respiratory infections in the horse were published to date. This paper describes two equine cases of bacterial infections where Stenotrophomonas maltophilia could be isolated in pure culture. One horse, a multiparous mare, presented with bacterial cystitis and responded well to a ten day course of antibiotics without relapse. The other horse, a polo pony, was diagnosed with advanced bacterial endocarditis of the pulmonary valve. The large vegetations led to stenosis with concurrent cor pulmonale and the horse died within a few hours after admission. The pathological examination confirmed the clinical diagnosis and revealed additional metastatic pneumonia and lung abscesses due to embolisation. Stenotrophomonas maltophilia was isolated from the large vegetations, while the lung abscesses produced no bacterial growth. Despite a recommendation of tetracyclines and trimethoprim/sulfamethoxazole as drugs of choice against infections with Stenotrophomonas maltophilia, in both of our cases the germ was resistant against these antibiotics, but susceptible to marbofloxacin. In summary in horses Stenotrophomonas maltophilia should be taken into account even as a causative pathogenic agent of multiresistant bacterial infections in horses.

Rapid identification of Stenotrophomonas maltophilia by peptide nucleic acid fluorescence in situ hybridization

“…It is capable of causing serious disease in immuno-compromised patients and has been reported in cystic fibrosis (CF) patients with a yearly prevalence of up to 25% [2,3]. In veterinary medicine, an increasing number of studies indicate possible associations with respiratory disease [4,5], bacterial cystitis and endocarditis [6], urinary tract infections [7] and lymphadenitis [8]. Within the genus, S. maltophilia is the only species that is known to colonize and cause respiratory tract infections in humans and animals.…”