Infants with bacteremic urinary tract infections on short-term versus long-term parenteral antibiotics before oral antibiotics had similar outcomes, according to a study.

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While previous studies have shown short-term parenteral antibiotic therapy to be safe and equally effective in uncomplicated urinary tract infections (UTIs), short-term therapy safety in bacteremic UTI had not been established, Sanyukta Desai, MD, of the University of Cincinnati and Cincinnati Children’s Hospital and associates wrote in Pediatrics.

“As a result, infants with bacteremic UTI often receive prolonged courses of parenteral antibiotics, which can lead to long hospitalizations and increased costs,” they said.

In a multicenter, retrospective cohort study, Dr. Desai and associates analyzed a group of 115 infants aged 60 days or younger who were admitted to a group of 11 participating EDs between July 1, 2011, and June 30, 2016, if they had a UTI caused by a bacterial pathogen. Half of the infants were administered parenteral antibiotics for 7 days or less before being switched to oral antibiotics, and the rest were given parenteral antibiotics for more than 7 days before switching to oral. Infants were more likely to receive long-term parenteral treatment if they were ill appearing and had growth of a non–Escherichia coli organism.

Six infants (two in the short-term group, four in the long-term group) had a recurrent UTI, each one diagnosed between 15 and 30 days after discharge; the adjusted risk difference between the two groups was 3% (95% confidence interval, –5.8 to 12.7). Two of the infants in the long-term group with a recurrent UTI had a different organism than during the index infection. When comparing only the infants with growth of the same pathogen that caused the index UTI, the adjusted risk difference between the two groups was 0.2% (95% CI, –7.8 to 8.3).

A total of 15 infants (6 in the short-term group, 9 in the long-term group) had 30-day all-cause reutilization, with no significant difference between groups (adjusted risk difference, 3%; 95% CI, –14.6 to 20.4).

Mean length of stay was significantly longer in the long-term treatment group, compared with the short-term group (11 days vs. 5 days; adjusted mean difference, 6 days; 95% CI, 4.0-8.8).

No infants experienced a serious adverse event such as ICU readmission, need for mechanical ventilation or vasopressor use, or signs of neurologic sequelae within 30 days of discharge from the index hospitalization, the investigators noted. Peripherally inserted central catheters were required in 13 infants; of these, 1 infant had to revisit an ED because of a related mechanical complication.

“Researchers in future prospective studies should seek to establish the bioavailability and optimal dosing of oral antibiotics in young infants and assess if there are particular subpopulations of infants with bacteremic UTI who may benefit from longer courses of parenteral antibiotic therapy,” Dr. Desai and associates concluded.

In a related editorial, Natalia V. Leva, MD, and Hillary L. Copp, MD, of the University of California, San Francisco, noted that the study represents a “critical piece of a complicated puzzle that not only includes minimum duration of parenteral antibiotic treatment but also involves bioavailability of antimicrobial agents in infants and total treatment duration, which includes parenteral and oral antibiotic therapy.”

The question that remains is how long a duration of parenteral antibiotic is necessary, Dr. Leva and Dr. Copp wrote. “Desai et al. used a relatively arbitrary cutoff of 7 days on the basis of the distribution of antibiotic course among their patient population; however, this is likely more a reflection of clinical practice than it is evidence based.” They concluded that this study provided evidence that a “short course of parenteral antibiotics in infants [aged 60 days or younger] with bacteremic UTI is safe and effective. Although the current study does not address total duration of antibiotics [parenteral and oral], it does shine a light on where we should focus future research endeavors.”

The study authors reported that they had no conflicts of interest. The study was supported in part by a National Center for Advancing Translational Sciences grant and an Agency for Healthcare Research and Quality grant. The editorialists had no relevant conflicts of interest and received no external funding.

SOURCEs: Desai S et al. Pediatrics. 2019 Aug 20. doi: 10.1542/peds.2018-3844; Leva et al. 2019 Aug 20. doi: 10.1542/peds.2019-1611.