Research Article Serotyping and Antimicrobial Susceptibility Pattern of Escherichia coli Isolates from Urinary Tract Infections in Pediatric Population in a Tertiary Care Hospital Shweta Sharma, Nirmaljit Kaur, Shalini Malhotra, Preeti Madan, Wasim Ahmad, and Charoo Hans Department of Microbiology, PGIMER and Dr. RML Hospital, New Delhi 110001, India Correspondence should be addressed to Shweta Sharma; drshwetamicro@gmail.com Received 4 October 2015; Revised 28 January 2016; Accepted 8 February 2016 Academic Editor: Hin-Chung Wong Copyright © 2016 Shweta Sharma et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Urinary tract infections (UTIs) in pediatric population are associated with high morbidity and long term complications. In recent years, there is increased prevalence of Escherichia coli (E. coli) strains producing extended spectrum -lactamase, Amp C, and Metallo -lactamase, making the clinical management even more difcult. Tis study was aimed to detect the serotypes and to determine antimicrobial susceptibility profle of E. coli isolates from urine samples of children <10 yrs old. A total of 75 pure E. coli strains isolated from patients with symptoms of UTI and colony count ≥10 5 organisms/mL were included in the study. Antibiotic sensitivity pattern showed maximum resistance to nalidixic acid (98.7%), followed by ampicillin (97.3%), amoxi-clavulanate (96%), and fuoroquinolones (92%) while most of the isolates were found sensitive to piperacillin-tazobactam (13.3%), nitrofurantoin (5.3%), and meropenem (1.3%). 48% of the strains were ESBL producer (extended spectrum beta lactamase). 44% strains were typable withantisera used in our study and the most common serogroup was O6 (33.3%) followed by O1 (15.1%) and O15 (15.1%). To conclude, judicious use of antibiotics according to hospital antibiotic policy and infection control measures should be implemented to prevent spread of multidrug resistant organisms. 1. Introduction Urinary tract infections (UTIs) are one of the most com- mon infections encountered in the clinical practice, and in pediatric population it is associated with high morbidity and long term complications like renal scarring, hypertension, and chronic renal failure [1]. Early diagnosis, proper inves- tigation, adequate therapy, and prolonged careful follow-up in children with UTI will decrease chronic renal failure in adults. UTI is mainly associated with members of the Ente- robacteriaceae family and Escherichia coli (E. coli) are the most predominant pathogen causing UTIs [2]. E. coli that are associated with UTI are commonly named uropathogenic isolates, although there is evidence that diferent pathotypes may be related to UTI; however, uropathogenic E. coli (UPEC) is responsible for approximately 90% of all UTIs [3]. Uropathogenic E. coli (UPEC) possess virulence factors which help them to colonize the periurethral area, enter urinary tract, and cause retrograde infection. E. coli strains are normally identifed by serological typing of their H (fagellar), O (lipopolysaccharide), and, in some cases, K (capsular) surface antigens. Since, 176 O-serogroups had been described for E. coli [3]. In UPEC, the O-serogroups are related to the virulence factor profle of each strain. Previous studies reported that O1, O2, O4, O6, O7, O8, O15, O16, O18, O21, O22, O25, O75, and O83 serogroups are preferentially associated with UPEC strains [4, 5]. Each serotype of E. coli has an important role in clinical presentation of UTI, and the prevalence of diferent serotypes varies in diferent regions. In recent years, there has been an increase in the resistance to cephalosporins, fuoroquinolones, and trimethoprim among UTI cases, which is a growing cause of concern. In hos- pitalized patients, there is increased prevalence of E. coli strains producing extended spectrum -lactamase, Amp C, and Metallo--lactamase, making the clinical management even more difcult [6, 7]. Also clinicians must be aware of Hindawi Publishing Corporation Journal of Pathogens Volume 2016, Article ID 2548517, 4 pages http://dx.doi.org/10.1155/2016/2548517