Epidemiology and Antimicrobial Susceptibility of Gram-Negative Pathogens Causing Intra-abdominal Infections in Pediatric Patients in Europe—SMART 2011–2014

In this study, susceptibility varied among European Gram-negative isolates from pediatric intra-abdominal infections. Resistance, rates of extended-spectrum β-lactamase-positive isolates, and multidrug-resistance rates were substantially higher in isolates from hospital-associated infections than in those from community-associated infections and were higher in ICUs than in general wards, which suggests that different empiric therapy strategies are needed in different settings. The most common type of intra-abdominal infection (IAI) is appendicitis, which occurs most frequently in children and young adults. Yet, few studies on the microbiology of pediatric IAI are available, which is problematic because antimicrobial therapy for IAI usually needs to be initiated before microbiological culture results are available. With this study, we aimed to assess whether resistance patterns in pediatric IAI in Europe that would help clinicians select empiric therapy can be identified. Gram-negative pathogens (n = 1259) were collected from pediatric patients as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) in 16 European countries from 2011 to 2014. Minimal inhibitory concentrations (MICs) and extended-spectrum β-lactamase (ESBL) phenotype were determined by broth microdilution according to Clinical and Laboratory Standards Institute guidelines, and susceptibility was interpreted according to European Committee on Antimicrobial Susceptibility Testing guidelines. An IAI was defined as hospital- or community-associated if cultured ≥48 or <48 hours after admission, respectively. Overall, only imipenem and amikacin exceeded 90% susceptibility when all Gram-negative pathogens were combined, and ertapenem, cefepime, ceftazidime, piperacillin-tazobactam, and levofloxacin reached at least 85%. However, resistance, ESBL-positive, and multidrug-resistance (MDR) rates were substantially higher in isolates from patients with hospital-associated IAI than from those with community-associated IAI (eg, 14.1% vs 5.1% MDR isolates, respectively, among all Gram-negative pathogens), higher in isolates from intensive care units than in those from general wards, and higher in isolates from infants than in those from children ≥1 year of age. In addition, MDR rates varied markedly within Europe. These results indicate that empiric therapy of pediatric IAI in Europe should reflect not only regional and local resistance patterns but also higher resistance rates in hospital-associated infections, intensive care units, and infants.