A middle-aged woman developed fatal urosepsis due to a multidrug-resistant Escherichia coli strain representing sequence type ST131, a recently emerged, disseminated, multidrug-resistant extraintestinal pathogen, after presumably having acquired it from her extensively antibiotic-exposed sister with chronic recurrent cystitis. Susceptibility results (reported on day 4) showed resistance to the initially selected regimen.
CASE REPORTThe index patient was a middle-aged female with chronic, recurrent symptomatic urinary tract infections (UTIs) due to Escherichia coli. Her urine isolates had become increasingly antimicrobial resistant over a 5-year period, including having become, for the past several years, extended-spectrum betalactamase (ESBL) positive.Both the index patient and a younger sister had alpha-1-antitrypsin deficiency. Whereas the index patient was only mildly affected, the younger sister was severely affected, leading to long-term care facility placement and a referral for lung transplantation (which was denied, because of continued smoking). The index patient had cared for the younger sister in the index patient's home for several months during the summer prior to the younger sister's acute illness.Shortly after the younger sister's temporary residence in the index patient's home, she began to experience mild dysuria when voiding (no indwelling or intermittent urinary catheter use) and low-grade fever. After a week of progressive symptoms, she was admitted to the hospital for presumed pyelonephritis.On admission, the patient appeared to be in mild distress with right-sided flank pain. Her temperature was 37.6°C, pulse was 52 beats per minute, blood pressure was 153/82 mm Hg, and respirations were 24 per minute. Oxyhemoglobin saturation was 92% on 4 liters of oxygen. The right flank was tender. Laboratory findings included leukocytosis (17,800 cells/l) with 88% neutrophils. Urinalysis showed marked pyuria and bacteriuria. Ciprofloxacin (400 mg intravenously every 12 h) and stress-dose corticosteroids were administered.Over 3 days, her clinical status worsened, and she was transferred to the intensive care unit for septic shock, presumed to be secondary to pyelonephritis. Her white blood cell (WBC) count rose to 18,400 cells/l (29% band forms), and her serum creatinine level increased to 2.7 mg/dl. The patient received mechanical ventilation and vasopressor therapy. Renal ultrasonography revealed moderate right hydronephrosis; a right percutaneous nephrostomy tube was placed. Blood and urine cultures grew E. coli.Due to the patient's precipitous decline, antimicrobial therapy was broadened empirically by adding piperacillin-tazobactam, based on local antibiogram data. On hospital day 4, septic shock worsened, requiring additional vasopressor support. Susceptibility data, which were now reported, showed the E. coli isolates to be resistant to fluoroquinolones and extended-spectrum cephalosporins but susceptible to piperacillin-tazobactam, amikacin, carbapenems, and trimethoprim-sulfamethoxazole. Therap...