Serious bacterial infections in hospitalized febrile infants aged 90 days or younger: the traditional combination of ampicillin and gentamicin is still appropriate.

BACKGROUND

A change in the bacterial epidemiology of infantile serious bacterial infection (SBI) has raised concerns regarding the appropriate empirical antibiotic therapy.

OBJECTIVE

To describe the epidemiological features of SBI in febrile infants in order to elucidate the appropriate empirical regimens.

METHODS

From 2005 to 2009, clinical and laboratory data were prospectively collected for all infants aged ≤ 90 days who were hospitalized for fever.

RESULTS

Of the 1584 febrile infants who met the study criteria, 149 (9.4%) had a culture-proven SBI: urinary tract infection in 128 (86%), urinary tract infection with bacteraemia in 11 (7%), bacteraemia in 7 (5%), enteritis with bacteraemia in 2 (1.3%), and meningitis in 1 (0.7%). Ninety-one percent of cases were caused by Gram-negative bacteria, mostly Escherichia coli (72%). Among the causative Gram-positive bacteria were Enterococcus spp. (4%) and group B Streptococcus (0.7%); no cases of Listeria monocytogenes infection were identified. Sixty-one percent of the causative bacteria were resistant to ampicillin. According to in vitro susceptibility testing, the combination of ampicillin and gentamicin provided appropriate antibiotic coverage.

CONCLUSIONS

Despite changes in the epidemiology of infantile SBI, the traditional combination of ampicillin and gentamicin is still appropriate for empirical treatment of febrile infants aged ≤ 90 days.