Primary Perinephric Abscess Due to Hydrogen Sulfide Producing Variant of Salmonella paratyphi A Anil Kumar, MD,* Sanjeevan K.V., MS, MCh,Þ Kavitha R. Dinesh, MD,* Vivek Vinod, MSc,* and Shamsul Karim, MD* Abstract: A 35-year-old man presented with a gradually worsening left-sided loin pain and high-grade fever 10 days in duration. He gave a history of left flank injury due to a road traffic accident 4 months previously, accompanied by pain and transient mild hematuria that was managed conservatively without further evaluation. Computed tomo- graphic scan revealed undisplaced fracture of the left 10th rib with a large perinephric hematoma/abscess causing significant compression and displacement of the left kidney. The collection was evacuated by open drainage, and its culture yielded a hydrogen sulfide (H 2 S)Yproducing variant of Salmonella paratyphi A resistant to nalidixic acid. Blood and urine cultures were sterile. Drainage with culture-specific antibiotics (ceftriaxone followed by cefixime) was curative. Primary perinephric abscess due to S. paratyphi A without any evidence of systemic involve- ment is rare and classically S. paratyphi A is H 2 S-negative. We hereby report a case of H 2 S-positive S. paratyphi A causing primary perinephric abscess of posttraumatic hematoma. Key Words: S. paratyphi A, abscess, nalidixic acid, hydrogen sulfide (Infect Dis Clin Pract 2011;19: 288Y290) I nfections in the kidney and perinephric space occur as a vari- ety of clinical entities that can be divided into intrarenal and perirenal pathology. Ten percent of renal cortical abscesses rup- ture through the capsule forming a perinephric abscess, which is difficult to manage and carries mortality as high as 12% if the diagnosis and treatment is delayed. Studies have reported that only 35% of the perinephric abscess had a correct diagnosis at initial presentation. 1 The basic pathology is due to the collection of purulent material between the kidney and the Gerota fascia. Escherichia coli, Proteus, Staphylococci, and Pseudomonas are the most common etiological agents and affect men and women equally. 2 Among other organisms that have been rarely reported to cause perinephric abscesses are Salmonella spp. and Streptococcus pneumoniae. 3 Common predisposing factors include diabetes mel- litus, renal calculi, ureteral obstruction, and vesicoureteric reflux. 4 The clinical differentiation is difficult, and computed tomographic (CT) scan is the best method to identify a renal cortical or peri- nephric abscess. 5 Here we present a case of a large perinephric abscess due to infection of posttraumatic hematoma, by H 2 S-producing variant of Salmonella paratyphi A resistant to nalidixic acid. The patient was managed successfully with open drainage and appropriate antimicrobial therapy. CASE REPORT The patient was a 35-year-old man who presented with a gradually worsening pain in the left side of the loin region associated with high-grade fever 10 days in duration. He had sustained an injury in his loin on the same side after a fall due to a road traffic accident 4 months earlier. Other than transient mild hematuria and mild to moderate degree of local pain, which could be managed by simple analgesics, he did not have any other difficulty and hence was left unevaluated further. There was no history of fever, chills, or bowel symptoms in the subsequent 4 months after trauma and no urinary tract in- fection or hematuria ever in the past. At admission, his tem- perature was 39.8-C, pulse rate was 117 beats per minute, blood pressure was 120/72 mm Hg, and respiratory rate was 30 breaths per minute. Physical examination revealed fullness in the left renal angle, flanks, and hypochondrium, with generalized guard- ing, marked tenderness, and a vague lump in the region. Exam- inations of the chest, external genitalia, and other areas were unremarkable. Multidetector CT imaging study (Fig. 1) revealed frac- ture of the posterior aspect of the left 10th rib with a large heterogeneously hyperdense perinephric collection, consistent with an abscess and/or hematoma, around the left kidney, pre- dominantly in the lateral and posterior aspects of the kidney, measuring 17 Â 5 Â 6 cm 3 causing anterior and superior dis- placement and significant compression of the kidney. Renal parenchyma was normal with normal contrast enhancement. Renal vessels, right kidney, and urinary bladder appeared nor- mal. There was no feature of osteomyelitis at the site of rib frac- ture. Pertinent laboratory results included white blood cell count of 17,100/KL, with predominance of neutrophils, and C-reactive protein level of 133 mg/dL. Blood biochemistry for liver and kidney functions was within reference limits. The patient was started on empirical intravenous gentamicin 120 mg/d and oflox- acin 400 mg/d pending culture reports. Considering the large size and the significant amount of compression the abscess was causing to the left kidney, open drainage of the abscess was done through a small subcostal incision with evacuation of 300 mL of infected perinephric hematoma, which, on culture, grew gram- negative nonYlactose-fermenting colonies on MacConkey agar plates. The isolate was identified as Salmonella enterica var. paratyphi A by standard biochemical and serological agglutina- tion methods (Remel, Santa Fe, Kan). Further confirmation was done in the API ID32E identification system (BioMerieux, Inc, St Louis, Mo). The unusual feature of the isolate was that it produced moderate amount of H 2 S and gas in the triple sugar iron (TSI) agar slant. Serum Widal titers for O and AH antibodies CASE REPORT 288 www.infectdis.com Infectious Diseases in Clinical Practice & Volume 19, Number 4, July 2011 From the *Microbiology and †Urology, Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala, India. Correspondenceto: V. Anil Kumar MD, Microbiology, Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala 682041, India. E-mail: vanilkumar@aims.amrita.edu. Correspondence to: Sanjeevan K.V., Urology, Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala 682041, India. E-mail: drsanjeevan@ hotmail.com. The authors have no funding or conflicts of interest to disclose. Copyright * 2011 by Lippincott Williams & Wilkins ISSN: 1056-9103 Copyright © 2011 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.