Introduction Information regarding pediatric Escherichia coli invasive disease is limited.

Objective Characterize the invasive Escherichia coli infections in a tertiary care pediatric center in Lisbon.

Methods Retrospective study (2005–2007) of the epidemiologic, clinical and laboratorial variables and risk factors of invasive Escherichia coli infection.

Results A total of 35 cases were observed; 68% <12 months (22,8% newborns). Sixteen (45,7%) had chronic disease: short bowel syndrome-SBS (7), urinary tract anomalies (4), leukaemia (2), others (3). Other risk factors were: central venous catheter (CVC) (22,9%), immunosuppressive therapy (11,4%), prematurity (2%) and perinatal infectious risk (2%). Children >12 months presented chronic disease and CVC in 72,7% and 36,4% cases, respectively. Clinical presentations were sepsis(48,6%), occult bacteremia (11,4%), other bacteremias (28,6%), pneumonia (8,5%), meningitis (5,7%), others (5,6%). Antimicrobial resistance was significant for ampicillin (80,6%), piperacillin (51,7%), trimethoprim/sulfamethoxazole (42,4%) and first generation cephalosporins (34,3%). Resistance rate was 3% for gentamicin and 13,6% for third generation cephalosporins. An increase in resistance to ampicillin occurred during the studied period. Complications occurred in 12 (36,4%) children: coagulopathy (9), altered ionic or acid-basis status (9), renal (3) or hepatic (3) dysfunction and cardiac failure (2). Coagulopathy was more common in children with chronic disease and CVC (50% vs 10,5%; p = 0,03; 66,6% vs 18,5%, p = 0,02). Seven children (20%) needed supportive therapy: blood transfusion (7), inotropics (4), mechanical ventilation (2); this was more frequent in children with chronic disease (46,1% vs 5,2%;p = 0,01). The mortality was 5,7%.

Conclusions Escherichia coli invasive disease affects manly young children, but also older children with risk factors. SBS was the most common chronic predisposing condition and may require special attention. Accounting to high rate of ampicillin resistance, we suggest a review of the empirical therapy in the risk groups. Resistance to cephalosporins is an emerging problem that needs further evaluation.