Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs) colonization as a risk factor for developing ESBL infections in pediatric cardiac surgery patients: “retrospective cohort study”

BACKGROUND Children with cardiac defects need many hospitalizations and repetitive antibiotic therapies, with an increasing risk of colonization with multidrug-resistant bacteria (MDRB) such as extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) Post-operative infections with these bacteria in paediatric cardiac surgery are life threatening. This article aims to study the prevalence of ESBL colonization among paediatric cardiac surgery patients, and to compare occurrence of post-operative infections with and without ESBL colonization. We also aim to study the correlation between the onset of postoperative infection and other parameters such as age, length of stay and preoperative antibiotic therapy. METHODS A retrospective cohort study included paediatric cardiac surgery patients in Cheikh Zaid hospital in Rabat, Morocco, between the 1st of January 2011 and 31 December 2014. A screening for ESBL colonization was requested for children who had a risk factor (previous hospitalization and/or taking antibiotics) at admission. Swabs were collected from three sites (throat, nose and anus). Two groups were compared - patients colonized and not colonized with ESBLs. Statistical analysis was performed using R software. RESULTS ESBL colonization screening was performed in 111 patients. Positive colonization was detected in 17 cases (15%). Klebsiella pneumoniae (KP): 9 (53%) was the most frequently isolated species. Among the 17 patients, 23.5% (4/17) developed a postoperative infection due to ESBLs versus only one patient without colonization (1%). There was a statically significant difference in terms of occurrence of postoperative infection between the two groups (p = 0.001). Relative risk of developing a postoperative infection with positive colonization was 22 (95% CI, 8.37-58.5). CONCLUSIONS The analysis of colonization with multidrug-resistant bacteria and the prevention of nosocomial infections appear to be important challenges for paediatric cardiac surgery. Systematic screening of ESBL colonization for cardiac surgery could have a significant contribution, on one hand to guide prophylactic antibiotic therapy of patients, and on the other, to prevent spread of those infections.