Drug Sensitivity Pattern ofe. coli Causing Urinary Tract Infection in Diabetic and Non-diabetic Patients

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1 The Journal of International Medical Research 1996; 24: in Diabetic and Non-diabetic Patients F JINNAH\ M S ISLAM\ M A K RUMI\ M G MORSHED 2 AND F H UQ3 'Department of Microbiology and Immunology, BIRDEM Hospital, Dhaka, Bangledesh; 2Institute of Life Sciences, Jahangirnagar University, Savar, Dhaka, Bangladesh; 3Medical Department, BEXIMCO Pharmaceuticals Ltd, Dhaka, Bangladesh Escherichia coli was isolated from 65 urine samples out of 300 specimens collected from diabetic and non-diabetic patients with urinary tract infections. All isolates were screened for susceptibility to commonly used antibiotics. No remarkable difference in sensitivity pattern was observed between the E. coli isolates from diabetic and non-diabetic. However, the isolates from hospitalized diabetic patients showed a clear difference in sensitivity; E. coli from this group was more resistant to commonly used antibiotics compared with those from non-hospitalized diabetic and non-diabetic patients. KEY WORDS: E. coli, UTI, ANTIBIOTICS, DIABETES, OUT-PATIENT, HOSPITALIZED, SENSITIVITY INTRODUCTION Urinary tract infections (UTIs) are an important cause of morbidity in diabetes, with the highest incidence in adult diabetic women' - 3 and hospitalized diabetic patients.' UTIs are more likely to cause serious complications in diabetic patients than in non-diabetics." Bacterial infections of the urinary tract are 296

2 F [innab, M S Islam, M A K Rutni et al. usually acquired by the ascending route from urethra to bladder - and may involve the kidney; haematogenous spread is less common." Escherichia coli is the organism most commonly isolated from both community- and hospital-acquired UTIs."-B Urinary tract infections caused by E. coli are usually treated with ampicillin, cotrimoxazole, gentamicin, nitrofurantoin, nalidixic acid and ciprofloxacin. The widespread availability of antimicrobial agents has not altered the incidence of UTI; variations in antibiotic sensitivity have been reported by several investigators and the resistance pattern is found to be dependent on the availability and/or indiscriminate use of drugs." Diabetic individuals are predisposed to infections and these infections complicate the control of the diabetes. Upper urinary tract involvement is common in diabetic patients with UTI, and complications frequently arise.' Therefore, early detection and judicious antibacterial therapy are essential in these patients. In this study, we investigated the bacterial cultures isolated from urine samples collected from diabetic patients with UTI. The E. coli isolates were screened for antibiotic sensitivity to assess whether drug resistance is a factor in the severity and complications of UTI in diabetic patients. PATIENTS AND METHODS PATIENTS A total of 300 patients with UTI were randomly selected for this study, 150 diabetic and 150 non-diabetic. The patients were of either sex and from a range of age groups. In the diabetic group, an equal number of hospitalized and non-hospitalized subjects was included. The cause of hospitalization was not necessarily UTI. METHODS A mid-stream morning urine sample (outpatients/hopitalized ambulant patients: first urine voided in the morning: hospitalized catheterized patients: samples collected between 6.30 am and 8.00 am) of 2-5 ml was collected in sterile test tubes from the selected patients. Aseptic measures were maintained during sample collection. The samples were spread on Blood agar and MacConkey's agar media and incubated at 37 C for 24 h. The pink-coloured, entire and smooth colonies cultured on MacConkey's agar were primarily identified as E. coli. This was subsequently confirmed by standard biochemical tests (triple sugar iron and motility, indole urea). Bacterial cultures other than E. coli were also isolated following standard techniques." The E. coli isolates were tested for antibiotic sensitivity by Kirby Bauer's disc diffusion method." Mueller Hinton agar medium was inoculated with the isolate with a 3 h pre diffusion time. Antibacterial agents tested were amoxycillin, cloxacillin, erythromycin, cephalexin, gentamicin and ciprofloxacin (Neofloxin"). The antibiotic discs were prepared by following standard techniques. Whatman paper no. 4 was punched out in 5 mm diameter discs which were sterilized in a hot air oven at 160 C for 1 h. After allowing the disc to cool to 8 10 C, 20 fll of sterile antibiotic solution were placed on each disc in appropriate concentration as follows: amoxycillin, 10 flg; doxallin, 1 flg; erythromycin, 15 flg; cephalexin, 30 flg;. gentamicin, 10 flg; ciprofloxacin, 10 ug. The discs were then dried in a refrigerator at 2-4 "C for 3-5 days. To evaluate the quality of our laboratory preparation, 15 isolates of E. coli were tested simultaneously with Nsofloxin" is the registered trade name of Beximco Pharmaceuticals, Bangladesh. 297

3 F [innoh, M S Islam. M A K Rumi et al. commercial (BBL Diagnostics, USA) and laboratory-prepared discs. RESULTS A total of 300 urine samples from 300 patients with UTIs were tested. About 30% of specimens (88/300) yielded significant bacterial growth: 23.33% from out-patient non-diabetic (35/150), 42.66% from outpatient diabetic (32/75) and 28.00% (21/75) from hospitalized diabetic patients. Among the isolates, E. coli was the pathogen most frequently cultured (65/88, 73.86%). Other pathogens (23/88, 26.13%) in order of frequency of isolation were Klebsiella spp., Enterococcus, coagulase negative Staphylococcus, Pseudomonas and Proteus (Table 1). Of the urine samples positive for E. coli, 25 were from non-diabetic and 40 from diabetic patients (25 out-patient and 15 hospitalized diabetics). It has been found that E. coli can be identified in 71.42% (25/35; Table 1) of positive cultures from urine samples of non-diabetic. In contrast, the incidence among all diabetic patients with UTI was found to be 78.13% (out-patient) and 71.42% (hospitalized), respectively. Other isolates also varied in incidence among these three groups of patients with UTI. All the E. coli isolates were screened for sensitivity to amoxycillin, cloxacillin, erythromycin, cephalosporin, gentamicin and ciprofloxacin. The results are shown in Table 2. TABLE 1 Isolation of pathogens from the urine samples of diabetic and non-diabetic patients DISCUSSION This study included hospitalized and nonhospitalized diabetic subjects with UTI as well as non-hospitalized non-diabetic subjects with UTI. E. coli was found to be the commonest pathogen overall in bacterial UTI, with the sensitivity pattern of E. coli to tested antibiotics varying among the isolates. This is probably due to the injudicious use of antibiotics in the treatment of infectious diseases. A number of studies have also reported such differences in the sensitivity pattern of E. coli isolates from UTIS. ' 2-14 It demonstrates that commonly used anti- Total Escher- Patient sample Positive ichia Entero- Staphylo- Pseudogroup examined cultures coli Klebsiella coccus coccus monas Proteus Non-diabetic Diabetic Hospitalized diabetic patients Total

4 F Jinnah, M S Islam, M A K Rumi et al. Drug Sensitivity Pattern of E. coli biotics such as amoxycillin, cloxacillin, erythromycin and cephalexin may not be the right choice in the treatment of UTI, particularly in patients with diabetes where the high incidence of E. coli infection makes patient management difficult. E. coli strains isolated from hospitalized diabetic patients were found to be more resistant to antibiotics as compared with isolates from out-patient diabetic or nondiabetic patients. These isolates showed resistance to most of the tested antibiotics. Recent studies have also reported that hospital-acquired strains of E. coli are more resist- TABLE 2 Drug sensitivity pattern ofescherichia coli isolated from diabetic and non-diabetic patients Antibiotics Used Study No. of Sensitivity & population patients resistance Amox Clox Ery Cepha Genta Cipro Non-diabetic 25 Sensitive Resistant Diabetic 25 Sensitive Resistant Hospitalized 15 Sensitive diabetic patients Resistant Amox, amoxycillin; Clox, cloxacillin; Ery, erythromycin; Cepha, cephalexin; Genta, gentamicin; Cipro, ciprofloxacin. TABLE 3 Number of antibiotics to which Escherichia coli (E. coli) isolates were resistant in diabetic and non-diabetic patients No. of antibiotics to which isolated E. coli strains were found to be resistant Patient E. coli group isolates Non-diabetic Diabetic Hospitalized diabetic patients Total

5 F Jinnah, M S Islam, M A K Rum; et al. ant than those isolated in communityacquired UTIS. 14 A clear difference in the sensitivity pattern has been observed between E. coli isolates from hospitalized and non-hospitalized diabetic cases. But no significant difference was found when the results were analysed by z' with Yate's corrections, between the isolates from out-patient diabetic and nondiabetic patients (Table 3). All isolates except those from hospitalized diabetic patients showed a good sensitivity to ciprofloxacin and gentamicin. The sensitivity of E. coli isolates from non-diabetic, out-patient diabetic and hospitalized diabetic patients with UTI to gentamicin (80%,76%,53.33%) and ciprofloxacin (96%, 96%, 60%) demonstrate that resistance in these hospitalized diabetics is quite high. This may be due to the frequent use of these antibiotics in hospital for the treatment of many infections. E. coli strains have also been isolated from hospital linen. Their sensitivity pattern was determined for the same antibiotics that were used to test isolates from urine samples. The sensitivity is found to be very similar to that of E. coli isolates from urine samples of the hospitalized diabetic patients (data not shown), which suggests the possibility of hospital-acquired infection among the hospitalized diabetics included in the study. ACKNOWLEDGEMENT We are grateful to Professor A K Azad Khan, Director, Research and Academy, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM), and the Medical Department, BEXIMCO Pharmaceuticals, for their kind cooperation and financial support during this study. REFERENCES 1 Williams DN, Knight AH, King H, et al: The microbial flora of the vagina and its relationship to bacteriuria in diabetic and non-diabetic women. Hr J Uro11975; 47: Hansen RO: Bacteriuria in diabetic and non-diabetic outpatients. Acta Med Scand 1964; 176: Ooi BS, Chan BTM, Yu M: Prevalence and site of bacteriuria in diabetes mellitus. Postgrad Med J1974; 50: Stamm WE, Martin SM, Bennett JV: Epidemiology of nosocomial infections due to gram negative bacilli: aspects relevant to development and use of vaccines. J Infect Dis 1977; 136: S Casey JI: Host defense and infections in diabetes mellitus. In: Ellenberg and Rifkin's Diabetes Mellitus Theory and Practice, 4th ed (Rifkin H, Porte D [r, eds). New York: Elsevier Science Publication Co., 1990; p Mims CA, Playfair JHL, Raitt 1M, et al: Urinary tract infections. In: Medical Microbiology. London: Mosby Europe Ltd, 1993; P Tapley N, Williams JD: Urinary tract infection in adults. Medicine International 1991; 4: Jolik WK, Willett HP, Amos DB, et al: Opportunistic enterobacteriaceae. In: Zinsser Microbiology, 20th ed. Norwalk, CT: Appleton and Lange, 1992; p Iasiska B, Szeuiawska A, Mazur E, et al: 300

6 F [inrush, M S Islam, M A K Bumi et al. Susceptibility to nitrofurantoin, biseptol and nalidixic acid of E. coli strains isolated from urine in the years Ann Univ Mariae Curie Sklodowska Med 1992; 47: Forland M, Thomas V, Shelokov A: Urinary tract infection in patients with diabetes mellitus. JAMA 1977; 238: Cheesbrough M: Antimicrobial sensitivity testing. In: The Medical Laboratory Manual for Tropical Countries, vol II: Microbiology. Oxford: Butterworth Heinmann Ltd, 1993; P James R, Johnson MD, Stamm WE: Urinary tract infection in women: diagnosis and treatment. Ann Infect Med 1989; 11: Johnson JR, Stamm WE: Diagnosis and treatment of urinary tract infections. Infect Dis Clin North Am 1987; 1: Lye WC, Chan RK, Lee EJ, Kumarashinghee GI: Urinary tract infection in patients with diabetes mellitus. J Infect 1992; 2: F [innah, M S Islam. M A K Rumi, M G Morshed andfhuq Drug Sensitivity Pattern of E. coli Causing Urinary Tract Infection in Diabetic and Non-diabetic Patients The Journal ofinternational Medical Research 1996; 24: Received for publication 12 January 1996 Accepted 19 January 1996 Copyright 1996 Cambridge Medical Publications Address for correspondence DR M G MORSHED Institute of Life Sciences, Iahangirnagar University, Savar, Dhaka, Bangladesh. 301