Perinephric Abscess Due toAchromobacter xylosoxidansfollowing De-Roofing of Renal Cyst

A51-year-old male, who had undergone laparoscopic deroofing of a simple renal cyst on the left side two years ago, presented with left flank pain of one month’s duration near the port site, along with low-grade fever. There was no abdominal distension or mass, nor alteration in bladder or bowel habits. He was not a diabetic nor had he any other important medical history. Physical examination revealed a temperature of 100.4 F, soft abdomen with severe tenderness over the left iliac fossa, and unremarkable left flank and costovertebral angle. The white blood cell count was 19,000/mcL, and the serum creatinine concentration was 1.52 mg/dL. A magnetic resonance imaging scan of the abdomen revealed a collection with enhancing septations in the left posterior pararenal space, extending into the psoas and quadratus lumborum muscles and adhering to the posterolateral abdominal wall. There was left perirenal stranding (Fig. 1) and a small left renal upper polar cortical cyst (Fig. 2). Blood and urine culture studies yielded no growth. Empiric antibiotic therapy was of no benefit and the patient returned with a pointing abscess about to rupture. The collection was incised and drained after ruling out any urine leak from the left upper urinary tract by retrograde urography, and a closed suction drain was left in the abscess cavity. The pus sample sent for culture yielded growth of nonfermenting gram-negative bacilli, identified by VITEK 2 compact system (bioMerieux, Inc., St Louis, MO) as Achromobacter xylosoxidans with a 99% probability and an ‘‘excellent identification’’ confidence level. The isolate was susceptible to piperacillin, levofloxacin, co-trimoxazole, ceftazidime, cefoperazone-sulbactam, and meropenem, but resistant to aminoglycosides and tetracycline using Clinical and Laboratory Standards Institute (CLSI) break points for nonEnterobacteriaceae. The drain was removed on the fifth post-operative day and the patient was discharged on oral levofloxacin and cotrimoxazole. Three days after discharge, the patient returned in sepsis with similar complaints and pus draining from the incision. On retaking the history, it was determined that the patient had stopped taking the antibiotics after discharge. On examination, his temperature was 101.6 F and he had tenderness of the left flank. Abdominal ultrasonogram showed minimal residual collection at the abscess site. A second incision and drainage was performed immediately under cover of intravenous cefoperazone-sulbactam. A small amount of purulent material was drained and the abscess wall was debrided. The benign-looking small cortical cyst towards the upper pole was left undisturbed on both occasions. After 1 wk of intravenous antibiotic and supportive therapy, the patient was discharged in good health on oral co-trimoxazole and levofloxacin for 2 wks. On clinic follow-ups at 1 mo and 3 mos, there was no evidence of any continuing infection or any local symptom or abnormal findings on imaging studies other than the unchanged cortical cyst. Achromobacter xylosoxidans is a non-fermenting gramnegative, motile oxidase-positive bacillus belonging to the Alcaligenaceae family [1]. It is characterized by the ability to utilize xylose and glucose oxidatively. Identification using traditional phenotypic test often is unreliable and A. xylosoxidans can be mistaken for non-aeruginosa strains of Pseudomonas or for strains of Burkholderia cepacia complex. Achromobacter xylosoxidans is an opportunistic pathogen capable of causing nosocomial and community-acquired infections, with the source being either endogenous or from a contaminated aquatic hospital environment [2]. It frequently has been iso