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

The Journal of

International Medical Research

1996; 24: 296 - 301

Drug Sensitivity Pattern of

E.

coli

Causing Urinary Tract Infection in

Diabetic and Non-diabetic Patients

F

JINNAH\

M S

ISLAM\

M

A KRUMI\

M G

MORSHED2AND

F

HUQ3

'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

out-patients.

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."

F [innab,

M S

Islam,

M

A K Rutni

et al.

Drug Sensitivity Pattern of E.

coli

Causing Urinary Tract Infection

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 com-munity- and hospital-acquired UTIs."-B

Urinary tract infections caused by E. coli are usually treated with ampicillin, co-trimoxazole, gentamicin, nitrofurantoin, nal-idixic acid and ciprofloxacin. The wide-spread availability of antimicrobial agents has not altered the incidence of UTI; vari-ations 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 fre-quently 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 col-lected 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 ran-domly 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 hos-pitalized and non-hoshos-pitalized subjects was included. The cause of hospitalization was not necessarily UTI.

METHODS

A mid-stream morning urine sample (out-patients/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 asE. 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 follow-ing standard techniques."

The E. coli isolates were tested for anti-biotic sensitivity by Kirby Bauer's disc dif-fusion 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 concen-tration as follows: amoxycillin, 10flg; doxal-lin, 1flg; erythromycin, 15flg; 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 qual-ity of our laboratory preparation, 15 isolates of E. coli were tested simultaneously with

Nsofloxin" is the registered trade name of Beximco Pharmaceuticals, Bangladesh.

F [innoh, M S Islam.

M

A K Rumi et al.

Drug Sensitivity Pattern of

E.

coli

Causing Urinary Tract Infection

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 out-patient 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 fre-quency of isolation were Klebsiella spp., Enterococcus, coagulase negative Staphylo-coccus, PseudomonasandProteus(Table 1).

Of the urine samples positive for E.coli, 25 were from non-diabetic and 40 from dia-betic patients (25 out-patient and 15 hospit-alized 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 out-patients. In con-trast, 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.

DISCUSSION

This study included hospitalized and non-hospitalized diabetic subjects with UTI as well as non-hospitalized non-diabetic sub-jects with UTI. E. coli was found to be the commonest pathogen overall in bacterial UTI, with the sensitivity pattern of E. colito 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-TABLE 1

Isolationofpathogens from the urine samplesofdiabetic and non-diabetic patients Total

Escher-Patient sample Positive ichia Entero- Staphylo-

Pseudo-group examined cultures coli Klebsiella coccus coccus monas Proteus

Non-diabetic

150

35

25

5

2

3

out-patients Diabetic

75

32

25

3

2

out-patients Hospitalized

75

24

15

2

3

diabetic patients Total

300

91

65

9

4

4

3

3

F

Jinnah,

M S

Islam,

M

A K Rumi

et al.

Drug Sensitivity Pattern of

E.

coli

Causing Urinary Tract Infection

biotics such as amoxycillin, cloxacillin, erythromycin and cephalexin may not be the right choice in the treatment of UTI, particu-larly 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 non-diabetic patients. These isolates showed resistance to most of the tested antibiotics. Recent studies have also reported that hospi-tal-acquired strains ofE. coliare more

resist-TABLE 2

Drug sensitivity pattern of Escherichia 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 3

9

9

12

20

24

out-patients Resistant

22

16

16

13

5

1

Diabetic

25

Sensitive

9

14

11

12

19

24

out-patients Resistant

16

11

14

13

6

1

Hospitalized

15

Sensitive

1

1

8

9

diabetic patients Resistant

15

15

14

14

7

6

Amox, amoxycillin; Clox, cloxacillin; Ery, erythromycin; Cepha, cephalexin; Genta, gentamicin; Cipro, cipro-floxacin.

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 isolatedE. coli strains were found to be resistant

Patient E. coli group isolates 0 1 2 3 4 5 6 Non-diabetic

25

3

6

3

9

3 out-patients Diabetic

25

5

4

7

5

2

out-patients Hospitalized

15

2

4

5

4 diabetic patients Total

65

8

10

12

18

10

6

F Jinnah, M

S

Islam,

M

A K Rum;

et al.

Drug Sensitivity Pattern of

E.

coli

Causing Urinary Tract Infection

ant than those isolated in community-acquired UTIS.14

A clear difference in the sensitivity pat-tern has been observed between E. coli iso-lates 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 non-diabetic patients (Table 3). All isolates except those from hospitalized diabetic patients showed a good sensitivity to cipro-floxacin 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%) demon-strate that resistance in these hospitalized diabetics is quite high. This may be due to the frequent use of these antibiotics in hos-pital for the treatment of many infections.E. coli strains have also been isolated from

hos-pital 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 pos-sibility 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 Pharmaceut-icals, for their kind cooperation and finan-cial support during this study.

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coli

Causing Urinary Tract Infection

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F [innah, M S Islam. M A K Rumi, M G Morshed andFHuq

Drug Sensitivity Pattern ofE. coliCausing Urinary Tract Infection in Diabetic and Non-diabetic Patients

The Journal of International Medical Research

1996; 24: 296 - 301

Received for publication 12 January 1996 Accepted 19 January 1996

©Copyright 1996 Cambridge Medical Publications

Address for correspondence DR

M G

MORSHED