Colonization With Antimicrobial-Resistant Gram-Negative Bacilli at Neonatal Intensive Care Unit Discharge

Abstract

Background: The epidemiology of the colonization of infants with antimicrobial-resistant Gram-negative bacilli (GNB) at discharge from the neonatal intensive care unit (NICU) is not well understood.

Methods: A multicenter study in which rectal surveillance samples for culture were obtained at NICU discharge from infants hospitalized ≥14 days was performed. Factors associated with colonization with GNB resistant to gentamicin, third/fourth-generation cephalosporin agents, or carbapenem agents were assessed by using a fixed-effects model.

Results: Of these infants, 9% (119 of 1320) were colonized with ≥1 antimicrobial-resistant GNB. Prolonged treatment (≥10 days) with meropenem or third/fourth-generation cephalosporin agents or treatment for ≥5 days with a β-lactam/β-lactamase combination agent were associated with an increased risk of colonization with GNB resistant to gentamicin. Surgery and ≥5 days of treatment with third/fourth-generation cephalosporin agents, a β-lactam/β-lactamase combination agent, or metronidazole were associated with an increased risk of colonization with GNB resistant to third/fourth-generation cephalosporin agents. Female sex and prolonged treatment (≥10 days) with meropenem were associated with colonization with GNB resistant to carbapenem agents.

Conclusions: Prolonged treatment with broad-spectrum antibiotics was associated with the colonization of infants with antimicrobial-resistant GNB within 7 days of NICU discharge. These findings suggest the potential for dissemination of resistant GNB from colonized infants to other NICUs, the community, or pediatric long-term care facilities. Antimicrobial stewardship efforts aimed at improving appropriate antibiotic use could have a beneficial effect on the emergence of antimicrobial-resistant GNB in the NICU population.

Keywords: antimicrobial resistance; cephalosporin agents; gentamicin; meropenem; risk factors.

Figure 1.

Numbers of subjects from the multicenter prospective study used in the analysis of infant colonization with antimicrobial-resistant GNB within 7 days of NICU discharge. The study sample included 1320 infants with a complete set of 3 surveillance swabs: 1 swab of the anterior nares for S aureus, 1 swab of the skin for S aureus, and 1 perirectal swab for GNB and enterococci (results of testing for S aureus and enterococci are not provided). Abbreviations: GNB, Gram-negative bacilli; LOS, length of stay; NICU, neonatal intensive care unit.