321 P akistan V eterinary J ournal ISSN: 0253-8318 (PRINT), 2074-7764 (ONLINE) Accessible at: www.pvj.com.pk Detection of Class 1 and 2 Integrons, β-Lactamase Genes and Molecular Characterization of Sulfonamide Resistance in Escherichia coli Isolates Recovered from Poultry in China Jam Kashif § , Rehana Buriro § , Javed Memon, Muhammad Yaqoob, Jamila Soomro § , Diao Dongxue, Huang Jinhu and Wang Liping* Key Lab of Veterinary Pharmacology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095; Peoples Republic of China; § Also affiliated with Sindh Agriculture University, Tandojam, Pakistan *Corresponding author: wlp71@163.com ARTICLE HISTORY ABSTRACT Received: Revised: Accepted: January 14, 2013 March 02, 2013 March 14, 2013 Key words: β-lactamase E. coli Integrons Poultry Sul genes This study aimed to detect integrons, β-lactamase genes and to characterize sulfonamide resistant E. coli isolates recovered from poultry. All the isolates (n=38) were investigated for the presence of integrons, Sul1, Sul2, Sul3 genes by PCR. Class 1 and class 2 integron were present in 79 and 16%, respectively. Additional resistance gene cassette embedded in class 1 and 2 integrons was aadA1, aadA5, dfrA17 and aadA22, dfrA, respectively. Sul1 and Sul2 genes were detected in 42.1 and 60.5% isolates, respectively. Both the Sul1 and Sul2 were present in 23% isolates. However, Sul3 gene was not present. Co-existence of Sul1 and Sul2 with class 1 integrons was found in 28.9 and 60.5% of class 1 integron positive isolates, respectively. Whereas, a less percentage of isolates showed a low level of resistance to β-lactams and no blaCTX-M, blaSHV and blaTEM was found. The MIC results showed resistance to sulfadiazine and sulfamethoxazole-trimethoprim in 88 and 84% isolates, resistance to penicillin, ampicillin, amoxicillin was 52, 52 and 44%, respectively. Chloramphenicol, florfenicol, tetracycline and gentamycin resistance was found in 51, 5, 42 and 67% isolates, respectively. This study revealed high frequency of class 1 integrons, Sul genes among poultry E. coli isolates, therefore further spread of Sul genes and integrons is predictable. ©2013 PVJ. All rights reserved To Cite This Article: Kashif J, R Buriro, J Memon, M Yaqoob, J Soomro, D Dongxue, H Jinhu and W Liping, 2013. Detection of class 1 and 2 integrons, β-lactamase genes and molecular characterization of sulfonamide resistance in Escherichia coli isolates recovered from poultry in China. Pak Vet J, 33(3): 321-324. INTRODUCTION Avian pathogenic E. coli (APEC) causes several infections in poultry which results in high mortality and leads to heavy economic losses to poultry industry worldwide. Antimicrobials are used for many decades as efficient and inexpensive antibacterial agent in poultry industry. Antimicrobial resistance is main reason for the treatment failure for all bacterial diseases and emergence of antimicrobial resistant pathogens in humans as well as in food producing animals is also a growing universal problem (Karczmarczyk et al., 2011). However, high prevalence of antimicrobial resistance genes (AMR- genes), including sulfonamide resistance genes has been reported in gram-negative bacteria of animals and humans source. Usually resistance to sulfonamides spreads extensively and rapidly by acquisition of Sul1, Sul2 or Sul3 (Trobos et al., 2008). Drug resistance monitoring programs have been implemented in many countries for the purpose of protecting the health of humans as well as animals. Antimicrobial resistant E. coli can also be reservoirs of AMR-genes and it can further spread the resistance determinants to other zoonotic bacteria which can also cause infections in animals and humans (Aarestrup, 2004). Assessment of antimicrobial resistance at molecular level is a useful tool for understanding the contribution of genetic elements responsible for developing and dissemination of resistance in bacteria (Alekshun and Levy, 2007). Multidrug resistant bacteria is considered a potential risk to human health through food borne infections with super bug and resistant pathogens or because integrons (Box et al., 2005). Horizontal gene transfer is also a main factor for the transfer of resistance genes from one bacterium to another (Warnes et al., 2012). It is reported that genes encoding antimicrobial resistance are often RESEARCH ARTICLE