1704. Stenotrophomonas maltophilia Infection in a Neonatal Intensive Care Unit (NICU): A Retrospective Study of Risk Factors and Outcomes in an Inner-City Hospital

BACKGROUND: Stenotrophomonas maltophilia is an aerobic, non-fermenting, Gram-negative bacillus associated with opportunistic and multi-drug resistant infections. The objective of this study was to identify risk factors and outcomes associated with S. maltophilia isolation or infection in a level IIIB neonatal intensive care unit (NICU). METHODS: This was a retrospective matched case-control study. Cases were matched 2:1 for birth weight, gestational age, and year of NICU admission. The Chi-square test and Fisher’s exact test were used for comparisons of categorical variables. Continuous variables were analyzed with the Mann-Whitney U test. RESULTS: A total of 15 S. maltophilia isolates were identified from 15 neonates between January 1, 2008 and April 1, 2020 and matched to 30 controls. Median birth weight and gestational age of the cases was 675 g (IQR, 522.5-997.5 g) and 26 weeks (IQR, 24.86-27.14 weeks), respectively. The trachea was the most frequent site of isolation (9 of 15 isolates); colonization was suspected in 2 cases. Other sites included blood (1 case), conjunctiva (2 cases), and peritoneum (3 cases). The following factors were associated with risk of isolation or infection in cases compared to controls: total days of antibiotic exposure (24 vs 15 days, P = 0.01), total number of antibiotic courses (3 vs 2.5, P = 0.043), total days of broad-spectrum antibiotic exposure (19 vs 9.25 days, P = 0.015), and total days of meropenem exposure (9 vs 3 days, P = 0.008). Total length of NICU stay was significantly longer among cases versus controls (134 vs 68.5 days, P = 0.006). Mortality rate was also significantly higher in cases versus controls (N = 15, 33.33% vs N = 30, 0%; P < 0.001); 3 of 3 infants with peritoneal infection died. All 15 isolates were initially susceptible to levofloxacin, and 14 were susceptible to trimethoprim-sulfamethoxazole. CONCLUSION: Broad-spectrum antibiotic exposure, especially to meropenem, may lead to selection of resistant bacteria and promote S. maltophilia colonization and infection. S. maltophilia isolation or infection was associated with increased length of NICU stay and mortality. DISCLOSURES: All Authors: No reported disclosures