Frequency of Extended-Spectrum Beta-Lactamase Producing Organisms Causing Urinary Tract Infection and Their Antibiotic Sensitivity Pattern

Background: The spectrum of bacteria causing urinary tract infection (UTI) and their antibiotic sensitivity pattern is not uniform. Escherichia coli and Klebsiella sp. are two common organisms responsible for UTI through-out the world. The incidence of UTI due to infection with extended-spectrum beta-lactamase (ESBL) producing organisms are increasing. This study was aimed to describe the frequency of ESBL positive organisms causing UTI and their antibiotic sensitivity pattern. Methods: This cross-sectional study was done in the Department of Internal Medicine, BIRDEM General Hospital from January to April, 2016. Results: Total number of patients was 137 with females predominance (M:F ratio 1 : 3.7). Mean age was 60.3 ±11.7 years. Most patients (131, 95.6%) of the study population were diabetic and glycaemic control was poor (mean HbA1c 9.3 ±2.3) in these subjects. Common symptoms were fever, vomiting, increased urinary frequency, dysuria, suprapubic pain, and loin pain. Neutrophilic leukocytosis was common (94.9%). E. coli (73.7%) was the commonest aetiological agent followed by Klebsiella (8.8%), Enterococcus (4.4%), Citrobacter (3.6%), Staphylococcus aureus (3.6%), Acinetobacter (2.9%), Enterobacter (1.5%), and Pseudomonas (1.5%). Over half of E. coli and of Klebsiella sp. and 100% of Enterobacter organisms were ESBL positive. Imipenem (100%), amikacin, netilmycin,and nitrofurantoin were among the most sensitive antibiotics. Conclusion: More than half (71, 51.82%) of UTI cases were due to ESBL positive organisms. Imipenem, amikacin, netilmycin, and nitrofurantoin remain the drug of choice.


K K K K Ke e e
e ey w y w y w y w y wor or or or ords: ds: ds: ds: ds: antibiotic; extended-spectrum beta-lactamase; sensitivity; urinary tract infection.

Introduction
2][3] Antibiotics are the cornerstone for treating UTI.5][6] These organisms are inherently resistant to penicillins and cephalosporins; thus treatment with these drugs are of no use.Increasing age, diabetes mellitus (DM), catheterisation, history of hospitalization and antibiotic intake are risk factors for ESBL positivity.
*Not all specimens were tested against all antibiotics listed; sen=sensitive; res=resistant; PPC=piperacilin.

Discussion
In this cross-sectional study, we have evaluated the frequency of ESBL positive organisms causing UTI and their antibiotic sensitivity patterns in a tertiary care setting of Bangladesh.
Mean age of the study population was 60.3 ±11.7 years.In two different reports from Dhaka, Bangladesh, patients suffering from UTI were of much lower age 6,9 but patients having infections due to ESBL positive organisms had a mean age of 71 years in Spain. 7 current study, it was seen that, 60.4% of E. coli and 58.3% of Klebsiella sp. were positive for ESBL.This frequency is much higher than previous four reports from Bangladesh. 5,6,9,10BL positive organisms are increasing in Korea and USA.In Korea Regarding antibiotic sensitivity patterns, most organisms were sensitive to imipenem, aminoglycosides and nitrofurantoins.Carbapenems were the most sensitive antibiotic in India 8 , Nepal 13 , Korea 11 , Spain 7 and other reports from Bangladesh. 5,6,9,10mitations of the study The study duration was short and sample size was small.It was a hospital based study and most of the patients were diabetic.Patterns of ESBL positive micro-organisms and their antibiotic sensitivity in non-diabetic population and in community are not clear.

Conclusion
In this study, it was found that two-thirds of the E. coli and Klebsiella sp.causing UTI were ESBL positive.Imipenem, amikacin, netilmycin, and nitrofurantoin remain the drug of choice.It might be recommended that urine samples should be sent for culture and antibiotic sensitivity testing before starting antibiotic in suspected UTI cases and every laboratory should routinely screen for ESBL positivity.
Patients with no/insignificant growth of pathogens or growth of candida, catheterized patients and pregnant patients were excluded from the study.Standard clean-catch technique was applied for collection of midstream urine.Urine samples were sent to microbiology laboratory in one hour, where it was inoculated in McConkey's and blood agar media within two hours.Those with growth of micro-organisms were further tested for antibiotic sensitivity using double disc-diffusion methods.Data were collected in semi-structured case record forms.Data were analyzed by using SPSS version 20.0.Results were presented in tables.
82it was 3.6% in 2006 and 14.3% in 2011.In USA12it was 4% in 2006 and 14% in 2012.In one report from Nepal ESBL positive E. coli and Klebsiella sp. were responsible for UTI in 13.41% and 16.55% cases respectively.One North Indian report showed these figures 5% and 13% respectively.8