[Analysis of clinical characteristics and antimicrobial resistance of carbapenem-resistant Acinetobacter baumannii infections in children].

Objective: This study aimed to summarize the clinical characteristics and antimicrobial resistance of carbapenem-resistant Acinetobacter baumannii (CRAB) infections in children, identify its risk factors and to raise the level of diagnosis and treatment of this disease.

Method: The data of clinical and antimicrobial susceptibility of 32 cases of CRAB and 64 cases of carbapenem-susceptible Acinetobacter baumannii (CSAB) infections as control seen between January 1, 2004 and December 31, 2010 in Yuying Children's Hospital Affiliated to Wenzhou Medical College were analyzed retrospectively.

Result: Thirty-two cases of CRAB infections were identified, 21 were male and 11 female. The ages ranged from 1 day to 16 years (median age 43 days) ,among whom 14 (44%) were aged < or = 28 days; 28 cases (88%) were diagnosed as hospital-acquired pneumonia (HAP) and 4 cases (12%) had wound infection. The common primary diseases of the cases were neonatal respiratory distress syndrome (n = 12, 38%), followed by congenital heart disease (n = 5,16%) and open fractures (n = 5,16%). Before the isolation of CRAB, 10 cases (31%) had received major surgery;29 patients (91%) had stayed in ICUs, 26 cases (81%) had received tracheal intubation and mechanical ventilation,the ventilation time was 2 -249 days (median: 12 days). Carbapenem was used in 17 cases (53%) previously, 13 (41%) had received beta-lactam/beta-lactamase inhibitor combinations, 8 (25%) had used 3rd-generation cephalosporins within 2 weeks before the isolation of CRAB. Sixteen cases (50%) were cured, 12 cases (38%) were improved, parents of 1 case(3%) automatically gave up hospitalization without being cured and 3 cases (9%) died. Forty-nine CRAB strains were isolated from the 32 cases, accounting for 10. 4% of AB isolation strains in the same period, in which 40 strains (82%) were isolated from sputum specimens and 9 strains (18%) from open wounds secretions. All 49 strains showed multidrug-resistance (MDR), of which 13 strains (27%) were pandrug-resistant (PDR) to the common antimicrobials. The rates of resistance to ampicillin-sulbactam and cephalosporins were 90% and more than 85%, respectively; while the rates of resistance to cefoperazone-sulbactam were 19%, the lowest among the tested agents. In multivariate analysis, receiving surgery (OR = 8.450), tracheal intubation and mechanical ventilation for more than 10 days (OR = 6.366) and previous use of carbapenems (OR = 7.084) were independent risk factors for CRAB infections.

Conclusion: Nosocomial infections in children due to CRAB infections mainly cause HAP and open wound infection. Previous surgery, prolonged tracheal intubation and mechanical ventilation for more than 10 days and previous carbapenems therapy within 2 weeks before the isolation of CRAB were independent risk factors for CRAB infections. CRAB showed MDR or even PDR to the common antimicrobials, which made great difficulties in antibiotic choices.