A 45-year-old male patient, truck driver by occupation, was admitted to our hospital with intense right-sided upper abdominal pain and right-sided chest pain of 10-days duration. He also complained of accompanying fever of the same duration. Prior to his admission, he had consulted another hospital and had received some non-specific medication without any relief, for which he was referred to our hospital. The patient gave a history of alcohol intake (moderate amount) since the last 10 years; however, he was otherwise apparently healthy prior to this episode of current illness. He was not diabetic or hypertensive and there were no other significant medical or family history, including history of contact with tuberculosis. On physical examination, the patient was conscious and oriented. He was febrile and recorded a temperature of 37.8  C. His pulse rate, respiratory rate, blood pressure and oxygen saturation were recorded to be 109/min, 22/min, 130/90 mm of Hg and 94 % respectively. On abdominal examination, tenderness was elicited in the right hypochondriac region. Respiratory system examination revealed a right-sided pleural effusion with reduced air entry in right lung and basal crepitations in left lung. Rest of the systemic examination was normal.
Laboratory investigations revealed a raised alkaline phosphatase level of 363 IU/L, a slightly raised total bilirubin level of 1.6 mg/dL (raised direct bilirubin 0.76 mg/dL, normal indirect bilirubin 0.8 mg/dL), and a low albumin level of 2.5 g/dL. Hemogram reports showed an extremely high total leucocyte count of 38.09 x 109/L, neutrophilic leukocytosis with shift to left (polymorphs 90.4 %) and a low hemoglobin level of 117 g/L. Other parameters such as, total red blood cell count (4.85 x 1012/L) and platelet count (545 x 109/L), respectively were within normal limits. Serum electrolytes, random blood sugar level, and lipid profile were also within normal limits. The patient tested negative for anti-HIV-1/2 antibodies, anti-Hepatitis C virus antibodies, and for Hepatitis B surface antigen. An ultrasonogram of the abdomen revealed a well-defined hypoechoic mass of size 10.7 x 8.5 x 7.2 cm in the right lobe of liver suggestive of an abscess and confirmed by an abdominal computed tomography scan. Subsequently, pigtail catheterization was carried out under local anesthesia which drained approximately 350 mL of thick purulent brownish material which was submitted for various microbiological investigations. The patient was started on parenteral antibiotics (piperacillin-tazobactam and metronidazole) pending culture results. Other supportive management such as maintenance of oxygen saturation, correction of anemia and drainage of pleural fluid was provided as per protocol.
A Gram-stained smear of the abscess material showed plenty of polymorphs (50-70 per low power field) with lots of gram negative bacilli scattered in arrangement (Fig. 1A). Culture on MacConkey agar after 24 h of incubation yielded pure growth of non-lactose-fermenting colonies (Fig. 1B) consisting of oxidase-negative, motile, gram-negative rods identified as Stenotrophomonas maltophilia by the VITEK-2  automated microbial identification system (bioMerieux, Marcy l'Etoile, France). Antibiotic susceptibility testing of the isolate by the standard disc-diffusion test performed as per the Clinical and Laboratory Standards Institute guidelines showed the isolate to be susceptible to chloramphenicol, levofloxacin, minocycline and trimethoprim-sulphamethoxazole, but resistant to ceftazidime and ticarcillin-clavulanate. The individual minimum inhibitory concentrations of the various antibiotics by EzyMIC (HiMedia, Mumbai, India) were as follows - chloramphenicol (1 mug/mL), levofloxacin (1 mug/mL), minocycline (0.75 mug/mL), trimethoprim-sulphamethoxazole (0.25 mug/mL), ceftazidime (>=256 mug/mL) and ticarcillin-clavulanate (32 mug/mL). Other investigations including modified Ziehl-Neelsen stain for acid-fast bacteria, cartridge based - nucleic acid amplification test for Mycobacterium tuberculosis, wet-mount for motile trophozoites and culture for fungi were non-contributory. Culture of accompanying pleural fluid specimen as well as blood culture did not reveal any growth.
Antibiotics were changed to a combination of levofloxacin (750 mg once a day intravenous) with trimethoprim-sulfamethoxazole (160 mg + 800 mg two times a day orally) administered for 3 weeks. Simultaneously, drainage with pigtail catheterization was also continued for 2 weeks. Significant clinical and radiological improvement was noted after one week of therapy, with decrease of abdominal pain, remission of fever and significant resolution of abscess and pleural effusion. The laboratory findings also improved gradually. The patient was discharged on the 22nd day of admission, with advice to continue oral trimethoprim-sulfamethoxazole in the same dosage for a further duration of 2 weeks. Clinical examination at 2 months follow-up revealed complete resolution of symptoms without any fresh complaints or any recurrence of infection.