Photo Quiz: Diarrhea and Fever in a Child Returning from Africa

A previously healthy 22-month-old African-American female presented with a 5-day history of diarrhea and fever that had begun immediately upon return from a 2.5-month-long stay in Niger. She had been evaluated at an outpatient clinic, where she was found to be dehydrated, so she was given intravenous fluid replacement. Significant laboratory test results at that time included low levels of serum sodium (133 mmol liter−1), carbon dioxide (18 mmol liter−1), and albumin (2.3 g dl−1). Bacterial culture and parasite examinations of a stool specimen were unrevealing, and her peripheral blood smears were negative for blood parasites. The patient returned for reevaluation 2 days later due to ongoing fever, diarrhea, and poor oral intake. She was admitted to the hospital for further management. Blood and urine cultures were obtained, and she was started on intravenous fluids and ceftriaxone. The patient's older sibling, who had also traveled to Niger during the same time period, had a diarrheal illness that self-resolved 5 days prior to the case patient's hospital admission. Following 2 days of incubation in a continuous-monitoring blood culture instrument (BD Bactec 9240, BD Diagnostic Systems, Sparks, MD), Gram-negative bacilli grew in the aerobic blood culture bottles. Subcultures of the positive bottles yielded an organism with the phenotypic characteristics seen in Fig. 1. The urine culture grew 30,000 CFU ml−1 of extended-spectrum-beta-lactamase-producing Escherichia coli. Based on the results of the urine culture, antibiotic therapy was changed to imipenem due to suspected E. coli urinary tract infection with concomitant bacteremia. However, the blood culture isolate demonstrated pan-susceptibility, so antibiotic therapy was changed to intravenous ampicillin. FIG 1 Subculture of a positive blood culture bottle on MacConkey agar (left) and Kligler iron agar (right) inoculated with this organism. (For answer and discussion, see page 1461 in this issue [doi:10.1128/JCM.01414-13].)