Ostemyelitis by Pseudomonas aeruginosa in a dog from Rio de Janeiro, Brazil

LETTERS Ostemyelitis by Pseudomonas aeruginosa in a dog from Rio de Janeiro, Brazil MADAM Osteomyelitis is a local or generalised inflammation of the bone resulting from infection (Jackson & Pacchiana 2004). Exogenous osteomyelitis is most frequent after open fractures and surgical repair of closed fractures. Although Staphylococcus sp. are the most common isolate, other organisms may occasionally be recovered by bacterial culture (Jackson & Pacchiana 2004). P. aeruginosa are Gram-negative rods, nonmotile, nonspore forming and aerobes. In dogs, although this bacterium has been described as an agent of pyoderma, otitis media/externa and urinary tract infections, there are few reports of osteomyelitis caused by this agent (Adamo & Cherubini 2001). A male mixed breed stray dog around three years old was found with several bruises and left hindlimb lameness - probably as a result of being hit by a car. It presented with no fever, and the radiographic examination confirmed a complete fracture of the distal third of the tibia. The dog was treated with penicillin (40.000 UI/kg/IM – Bezentacil; Eurofarma) and gentamicin (2mg/kg/IV – Gentocin; Shering Plough), associated with ketoprofen (1mg/kg/SC – Ketofen; Merial). After nine days, due to a persistent purulent discharge, ceftriaxone (25mg/kg/IV – Rocefin; Roche) was administrated. After one week clinical signs still persisted and a sample was collected for bacteriology. The microorganism was identified based on morphological and colonial characteristics, besides biochemical standard tests, and tested for susceptibility to fifteen antimicrobial drugs, as gentamicin (10 µg), ciprofloxacin (5 µg), norfloxacin (10µg), enrofloxacin (5µg), amoxicillin-clavulanic acid combination (10 µg), ampicillin (10µg), cephalexin (30 mcg), cefadroxil (30 mcg), cephalotin (30mcg), ceftazidim (30 mcg), ceftriaxone (30 mcg), ceftiofur (30 mcg), azithromycin (15 mcg), chloramphenicol (30 mcg) and streptomicin (10 mcg). Bacteriology confirmed the presence of Pseudomonas aeruginosa in pure culture. The isolate showed in vitro susceptibility only to ciprofloxacin, norfloxacin and ceftazidime. It also presented intermediate results to streptomycin, enrofloxacin, gentamicin, ceftriaxone and azithromycin. According to these results norfloxacin (20 mg/kg PO, SID – Norflagen; Agener união) was used for 45 days, till complete remission of the clinical signs. Treatment of P. aeruginosa infections is challenging, since some strains have developed multidrug resistance. Isolation and culture of the bacterium followed by antimicrobial susceptibility testing is mandatory for a successful therapy. B. Penna, R. Varges, G. Martins, C. Cabral, S. Thomé, S. Gallardo, W. Lilenbaum. Laboratório de Bacteriologia Veterinária, Universidade Federal Fluminense. Rua Prof. Hernani Mello, 101 sala 309, Niterói – RJ, Brazil, CEP 24210-130 References ADAMO, P. F., & CHERUBINI, G. B. (2001) Discospondylitis associated with three unreported bacteria in the dog. Journal of Small Animal Practice 42, 352-355 JACKSON, L. C., & PACCHIANA, P. D. (2004) Common complications of fracture repair. Clinical Techniques in Small Animal Practice 19, 168-179.

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Journal of Small Animal Practice

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Vol 50

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September 2009

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© 2009 British Small Animal Veterinary Association

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