Diagnostic Accuracy of Point-of-Care Gram Stains in Obstructive Pyelonephritis due to Ureteral Stones.

Background: The diagnostic utility of point-of-care (POC) Gram stains for obstructive pyelonephritis with hydronephrosis is not well established. The current study aimed to assess the diagnostic accuracy of urine Gram stains in patients with obstructive pyelonephritis due to ureteral stones. Methods: A retrospective observational study was conducted on patients with obstructive pyelonephritis admitted to our hospital between January 2011 and December 2021. The diagnostic accuracy of Gram stains was evaluated based on the severity of hydronephrosis, including Gram stains performed by both trained physicians and microbiological technicians. Results: After analyzing 210 patients, POC Gram stains of bladder urine presented a sensitivity, specificity, positive predictive value, and negative predictive value of 86.8%, 81.8%, 93.7%, and 66.7%, respectively, for gram-negative rods and 65.7%, 83.4%, 48.9%, and 91.0%, respectively, for gram-positive cocci. The agreement between POC Gram stains and urine culture was good for gram-negative rods, with a kappa (κ) coefficient of 0.637 and agreement rate of 85.6%, and moderate for gram-positive cocci, with a κ coefficient of 0.435 and agreement rate of 80%. The agreement between POC Gram stains and bladder urine culture results for gram-negative rods was higher in the mild hydronephrosis group (κ coefficient = 0.677) than in the severe hydronephrosis group (κ coefficient = 0.466). Discrepancies in Gram stain results between physicians and technicians were observed in 21 of 180 cases (11.7%). Conclusions: POC Gram stains for gram-negative rods may be a useful diagnostic tool for obstructive pyelonephritis, particularly in cases of mild hydronephrosis.

Photobacterium damselae subsp. damselae bacteraemia in a patient with liver cirrhosis.

Photobacterium damselae subsp. damselae is a family of Vibrionaceae and exists in the marine environment. The organism rarely causes soft-tissue infection in humans; moreover, most of the infected individuals have a history of fishing or exposure to brackish water. We experienced the case of a 63-year-old patient with a history of liver cirrhosis (Child-Pugh class B) who presented with a fever and swelling of the left leg with pain. His symptoms developed after fishing and eating raw fish with exposure of brackish water. He was diagnosed with cellulitis, and Photobacterium damselae spp. damselae was detected in blood culture. The patient was treated with ceftazidime and minocycline and he was discharged after recovery. We need to be aware that in immunocompromised patients with cellulitis exposed to brackish water, organisms other than Staphylococci and Streptococci may be the causative organisms.