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March 1982, Volume 32, Issue 3

Original Article

Antibacterial Sensitivity Pattern in Urinary Tract Infection 1975-79

S. Iqbal Ahmad  ( The Laboratory, Garden Road, Karachi. )


Antibiotic sensitivity pattern of common causative organisms of urinary tract infection was studied during the period of January, 1975 to December, 1979. These patients were referred by practicing doctors from their clinics and various hospitals. Of 14778, urine samples 4720 (32%) yielded a growth of organisms more than 105/ml or between 104-105/ml. These isolates were identified and tested against the five antibacterial agents by disc diffusion technique (Gavan, 1971). A definite fall in the sensitivity of E. Coli and kiebsiella to Ampicillin was observed over a perjod of 4 years. jPMA 32:69, 1982).


The prevalence of urinary tract infection (U.T.I.) is very high(Wing, 1970). Sixty per cent of the total cases referred for bacteriological investigations to our laboratory were those of U.T.I. This infection requires urgent and proper treatment. Most of the patients with U.T.I. are treated without laboratory investigations and their progress is monitored by the clinical response. If “Best Guess” for the primary choice of antibiotic is going to be applied rationally a knowledge of the causative organisms and their behavior against antioacterials is essential. This can only be achieved by the statistical studies of organisms and their sensitivity pattern. (Gruncberg, 1977; Mc Allister et. al, 1971). A widespread and indiscriminate use of broad spectrum antibiotic in common and severe bacterial infection results in the emergence of resistant strains in a very short time (Garrod, 1972).
This study was planned to assess the sensitivity pattern of U.T.1. pathogens to five highly potent antibiotics namely Ampicillin, Co-timoxazole, Nitrofurantoin, Gentamicin and Kanamycin during a period of the last five years.

Methods and Material

Mid Stream Urines were received preferably collected at the laboratoy or brought by the patients within an hour in sterile containers. It was plated on Blood agar and mac-conky’s agar with a standard loop. Viable bacterial count more than 105/ml or between 104-105/ml were selected for identificatien and antibiotic sensitivity tests.
Kirby Bauer Single disc agar diffusion method of susceptibility testing was done on pure culture. The medium used was Mueller Hinton agar (ph 7.4). Sixty Millilitre of the medium was poured into 14 cm diameter petridishes. Plates were dried for 30 minutes and used within 4 days. Five colonies of the organisms were picked up and seeded in 4 ml T.S. broth Trypticase Soya broth containing 1% yeast extract) and incubated for 4 hours at 37°C. The growth turbidity ws compared with barium sulphate standard (0.5 ml of 0.048M Ba Cl2 (1.17% Ba Cl2 2H2O) in 99.5 ml of 1% H3 SO4 V/V). The growth density was adjusted by adding sterile water. The organisms were streaked evenly on the medium in 3 directions using a cotton wool swab. After the inoculum was dried, usually within 15 minutes, nine individual disos were applied by the help of forecep. The plates were incubated overnight at 37°.
According to the modified K.B. zone size interpretation chart for antibiotic sensitivity inhibition zone diameters were measured with the help of a ruler. (Lynch-1976). The results of the study are shown in Tables I-V.


The common pathogens of Urinary tract infection and their sensitivity pattern shown in table 4 points to slight and expected fall of sensitivity extended over a period of 4 years. The behavior of Escherichia coli and Kiebsiella Spp. against ampicillin should be seriously taken into consideration where the loss of sensitivity has been more marked. (Garrod, 1973).
Ampicillin is a semi synthetic penicillin belonging to the family of broad spectrum penicillins. It has a reputation of having least untoward effects and this has caused it to be used as the drug of first choice in medical practice even for minor illness. It is thought that almost all the Esch coli infection of Urinary tracts is an auto infection from the gut (Heather et at 1980). The Esch coli of the gut colonises at the preurethral area, from where ascending infection starts. Due to the indiscriminate use of Ampicil­tin the gut Esch coli may be a resistant type of B-lactamase producers or R plasmid type which gives a high percentage of resistance. In view of this antibiotic resistance, sensitivity studies were done by us on 500 specimens of faeces which had no sign of bacterial infection i.e. no mucus, blood or pus cells. Esch coli thus isolated were tested for ampicillin sensitivity and only 25% were found to be sensitive (Unpublished data). The percentage Ampicillin sensitivity of faecal Esch coli run almost paralled to the Ampicillin sensitivity of Esch coli found in the U.T.I.


1. Garrod, L.P. and O’grady, F. Antibiotic and chemotherapy. 4th ed. Edinburgh, Cheerchil, Livingstone, 1972, pp. 257, 400.
2. Gruneberg R.N. Antibacterial Susceptibility of Urinary pathogens as a Guide to treatment choice in the years 1971-1976.Proc. 10th Inter Congr. Chemother. Zurich 1977. Ed. Siegenthaler W. and Luthy R; 18-23. Sept. 1, 200-202.
3. Heather, J. Ct al. (1980) Uropathogenic properties of ftesiiant escherichia coil in recurrent Urinary tract infection. J. Med. Microbiol., 13:.
4. McAllister, T.A., Percival, A., Alexander, J. G., Boyce, J.M.H., Dulake, C. and Warmaid, P.T. (1971) The Sensitivities of Urinary pathogens. Multicentric study of Sensitivities of Urinary tract pathogens. Postgrad. Med. J. 47 (Suppl):7.
5. Wing A.J. (1970) Infections of tile Urinery tract. II. Management. Br. Med. J., 4:35.

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