<i>Chromobacterium violaceum</i> isolated from pleural effusion in cat and antimicrobial susceptibility profile: A rare case report

Objective: This study aims to present <i>Chromobacterium violaceum</i> isolated from a pleural effusion in an indoor-outdoor cat. Materials and Methods: A 3-year-old male domestic shorthair cat was brought to the hospital with dyspnea. The thoracic radiographs and ultrasound showed the presence of a pleural effusion. The thoracic fluid was sent for cytological analysis, reverse transcription polymerase chain reaction (RT-PCR) for feline infectious peritonitis (FIP), and bacterial culture. Results: Cytological findings illustrated the protein-rich modified transudate. Albumin: globulin ratio was 0.4. RT-PCR testing for FIP was negative. The bacterial culture presented a pure growth of violet-pigmented colonies on both sheep blood agar and MacConkey agar. The isolation was identified and further confirmed as <i>C. violaceum</i>. The isolation was susceptible to drugs in aminoglycosides, tetracyclines, macrolides, fluoroquinolones, and sulfonamide groups. Conclusion: <i>Chromobacterium violaceum</i>, a saprophytic Gram-negative bacterium, commonly inhabits stagnant water and soil in tropical and subtropical areas. It is considered an opportunistic bacterium in both veterinary and human medicine. Although <i>C. violaceum</i> infection is rare, the disease is extremely fatal. In Thailand, a few cases of humans infected with <i>C. violaceum</i> were reported; however, the bacterial infection has never been discovered in animals. This case report highlighted a rare opportunistic infection of <i>C. violaceumin</i> a cat in Thailand and suggested drugs of choice for clinical treatments.