Nair T Bhaskaran et al / IJRAP 2011, 2 (6) 1756-1757 International Journal of Research in Ayurveda & Pharmacy XXXX ISSN 2229-3566 Research Article www.ijrap.net EXTENDED SPECTRUM β-LACTAMASES (ESBL) IN UROPATHOGENIC ESCHERICHIA COLI, PREVALENCE AND SUSCEPTIBILITY PATTERN IN A SOUTH INDIAN CITY Nair T Bhaskaran 1 *, Bhat G Kishore 2 , Pai Vidya 1 , Shantharam Manjula 3 1 Department of Microbiology, Yenepoya University, Mangalore, Karnataka, India 2 Department of Microbiology, M.M’ s N.G. Halgekar Institute of Dental Science & Research Centre, Belgaum, Karnataka, India 3 Department of Biochemistry, Yenepoya University, Mangalore, Karnataka, India Received on: 09/09/11 Revised on: 26/10/11 Accepted on: 03/12/11 *Corresponding author Email: bhaskarmicro@yahoo.com ABSTRACT The treatment of Escherichia coli (E.coli) infections is becoming difficult because of multidrug resistance. Extended spectrum β-lactamase (ESBL) production among E.coli resulted in limitations of therapeutic option. In this study, 300 strains of uropathogenic E.coli strains were studied for ESBL production by disc approximation test and double disc synergy test. Antibiotic sensitivity pattern of ESBL producers and Non ESBL producers are performed by Kirby-Bauer’s disc diffusion technique. 56% of uropathogenic E.coli strains were ESBL producers. High degree of antibiotic resistance to gentamycin, norfloxacin, cotrimoxazole was seen among ESBL producers. Both ESBL producers and non-ESBL producers were sensitive to imipenum (100%). ESBL producers were susceptible to amikacin (84%), nitrofurntoin (91%) respectively. Keywords: Uropathogenic E.coli, Extended spectrum β-lactamase, Multiple Drug Resistance INTRODUCTION Uropathogenic E.coli is responsible for approximately 85% of urinary tract infections. Treatment of E.coli infections is becoming difficult because of multidrug resistance. Production of extended spectrum β-lactamase results in multidrug resistance and limitations of therapeutic options. 1-5 ESBL is a plasmid encoded β-lactamase capable of hydrolyzing extended spectrum cephalosporins i.e., first, second, third and forth generation cephalosporins, penicillins and aztreonam except cephamycins and carbapenems. 6 The number of ESBL producing strains among E.coli has been steadily increasing over the past years resulting in limitation in cephalosporin therapy. 7 E.coli has the ability to produce ESBL in large quantities and can spread among other strains during conjugation. The aim of the study is to find out the prevalence of ESBL production among uropathogenic E.coli and the drug resistance pattern of ESBL producers and non-ESBL producers, which is essential to guide appropriate antibiotic treatment. MATERIAL AND METHODS 300 non-repeating strains of uropathogenic E.coli included in the study. Strains were isolated from hospitalized patients of different age groups with clinical symptoms of urinary tract infections, which yielded >10 5 bacteria per ml of urine on semi quantitative urine culture. The E.coli strains were collected from three major tertiary care centre, Yenepoya Medical College hospital, Father Muller Medical College hospital and K.S. Hegde Charitable hospital which receive patients from Dakshina Kannada and Udupi district of Karnataka, Kasaragod and Kannur District of Kerala during July 2009 to June 2011. All the strains identified by IMVIC (Indole, Methyl red, Voges - Proskaur and Citrate) reactions and sugar fermentation reactions 8 . The strains were subjected to antibiotic sensitivity test and ESBL detection test. Antibiotic Sensitivity Test All the E.coli strains are subjected to Antimicrobial susceptibility test by standard Kirby-Bauer ’ s disc diffusion test. norfloxacin(10 µg), nitrofurantoin (300µg), gentamycin (15µg), cotrimoxazole (25µg), amoxiclav (20/10µg) cefotaxime (30µg) ceftazidime(30µg) amikacin (30µg), imipenem (10µg) were the antibiotics tested. The result is interpreted according to NCCLS criteria. 9 Test for ESBL production Screening of ESBL production was done by standard NCCLS criteria. Two disc of ceftazidime (30µg) and cefotaxime (30µg) were used for invitro susceptibility testing by Kirby-Bauer ’ s disc diffusion method. 8,9 Inhibition zone of <22 mm for ceftazidime and <27 mm for cefotaxime indicate a probable ESBL producing strain. ESBL Confirmation Test A lawn culture of the test organism on Muller Hinton agar is prepared. A disc of amoxycillin (20µg) plus clavulanic acid (10µg) is placed on the surface, then discs of cefotaxime (30µg) and ceftazidime (30µg) were kept 20 mm apart from the amoxiclav disc (centre to centre) incubated at 37 0 c overnight. The enhancement of the zone of inhibition of the cephalosporin disc towards the amoxiclav disc was considered as synergy and strain was considered as an ESBL producer. E.coli ATCC 25922 is used as the negative control in the procedure. 7, 9 RESULTS Out of 300 uropathogenic E.coli 168(56%) were ESBL producers. Multiple drug resistance was observed in ESBL producing strains of E.coli. However, all the strains of ESBL producer and non-ESBL producers were sensitive to imipenem. 10,11,12 amikacin and nitrofurantoin are the other two drugs to which more number of ESBL producers and non ESBL producers were sensitive. The sensitivity of ESBL producing and Non-ESBL strains to the other antibiotics tested is shown in Table 1. Table 1: Antibiotic susceptibility of ESBL producer and non-ESBL producer Antibiotics ESBL Producer n=168 ESNL non-producer n=132 Norfloxacin 16(10%) 118(90%) Gentamycin 45(27%) 117(89%) Nitrofurantoin 152(91%) 122(93%) Co-trimoxazole 50(30%) 66(50%) Amoxyclav 105(62%) 117(89%) Amikacin 141(84%) 117(89%) Imipenem 168(100%) 132(100%) DISCUSSION Production of β-lactamase is a major means by which gram negative bacteria exhibit resistance to β-lactam antibiotics. Extended spectrum β-lactamases (ESBL) are a group of enzymes that can hydrolyse a variety of β-lactams including cephalosporins, monobactem and penicillins. The global spread of ESBL producing