|Year : 2001 | Volume
| Issue : 1 | Page : 62-64
Cross-resistance between trimethoprim-sulfamethoxazole and other common antibiotics among urinary isolates of escherichia coli - an in-vitro retrospective analysis
BV Navaneeth, N Suganthi, MR Sandhya Belwadi
Department of Microbiology, M.S. Rainaiah Medical College (MSRMC) and Teaching Hospital, Bangalore, India
B V Navaneeth
Department of Microbiology, M.S. Ramaiah Medical College and Hospital, Gokula Extension, Bangalore - 560 054
Source of Support: None, Conflict of Interest: None
| Abstract|| |
472 non-repetitive urinary isolates of E.coli (349 resistant and 123 sensitive to trimethoprim-sulfametho.xazole) from patients with culture documented UTI were isolated between January 1998-December 1999. Data on antibiograrn of these isolates were fed into WHONET computer program. The relationship between trimethoprim-sulfamethoxazole (T-S) resistance and resistance to other common antimicrobials among E. coli was statistically analyzed by comparing T-S resistant with T-S sensitive isolates against other antimicrobial agents. T-S resistant E.coli were more likely to be resistant to ampicillin, augmentin, cejazolin and norfloxacin (P<0.001) but not for gentanicin and nitrofurantoin (P>0.05). T-S resistance among urinary isolates of E.coli may be a risk fatctor that would likely be associated with resistance to other antimicrobial agents used to treat UTI.
Keywords: Urinary Tract Infection; Trimethoprim-Sulfamethoxazole; Antimicrobial Cross Resistance; E.coli.
|How to cite this article:|
Navaneeth B V, Suganthi N, Sandhya Belwadi M R. Cross-resistance between trimethoprim-sulfamethoxazole and other common antibiotics among urinary isolates of escherichia coli - an in-vitro retrospective analysis. Indian J Urol 2001;18:62-4
|How to cite this URL:|
Navaneeth B V, Suganthi N, Sandhya Belwadi M R. Cross-resistance between trimethoprim-sulfamethoxazole and other common antibiotics among urinary isolates of escherichia coli - an in-vitro retrospective analysis. Indian J Urol [serial online] 2001 [cited 2019 Jul 21];18:62-4. Available from: http://www.indianjurol.com/text.asp?2001/18/1/62/37420
| Introduction|| |
Co-trimoxazole, a combination of trimethoprimsulfamethoxazole (T-S) is used as one of the representative first line agents in urinary tract infections (UTIs). There is increasing resistance to T-S among isolates of E.coli in developing countries. Its resistance is likely to be associated with resistance to other pharmacologically unrelated agents commonly used to treat ambulatory infections, including ampicillin, orally administered first generation cephalosporins and norfloxacin. Hence a preliminary correlation was attempted statistically to know the association between T-S resistance and resistance to other common antibiotics among E.coli.
| Patients and Methods|| |
The study was performed in the department of Microbiology, M.S. Ramaiah Medical College and Teaching Hospital, Bangalore. Between January 1998-December 1999. 472 non-repetitive isolates of E.coli were isolated from urine samples. Antibiotic susceptibility pattern of these E.coli isolates (349 resistant and 123 sensitive to T-S) was fed into WHONET computer programme. Bauer-Kirby disc diffusion' was the method followed for the antibiotic susceptibility test. Ampicillin (l0µ gms), amoxy-clavulanic acid (30 µ gms), cefazolin (30µ gms), gentamicin (10p -ms), nitrofurantoin (300µ gms), and norfloxacin (10 µ gms) are the common antibiotic discs (HiMedia) used apart from T-S (25µ gms). Comparison of resistance pattern between T-S resistant and T-S sensitive E.Coli to other antibiotics were analyzed. Statistical evaluation of resistance values obtained from both T-S resistant and T-S sensitive group was performed by Chi-square test.
| Results|| |
Out of 472 urinary isolates of E.coli, 349 were resistant (73.9%) and 123 were sensitive (26%) to T-S. Resistance pattern of T-S resistant and T-S sensitive urinary isolates of E.coli in relation to other antimicrobial agents are shown in the table. The analysis indicates that isolates resistant to T-S were more likely to be resistant to ampicillin, augmentin, cefazolin and norfloxacin (P<0.001). However no significant association was noted between T-S resistance and resistance to gentamicin and nitrofurantoin (P>0.05).
| Discussion|| |
The present study correlates well with the study from Canada showing similar correlation between T-S resistant and other antibiotics especially ampicillin. Of particular concern in T-S is the resistance often carried on transferable R factors that confer resistance to multiple antimicrobials, emphasizing the way one agent may effect resistance to many others. Study from Houston Texas shows 96% of 165 trimethoprim (TMP) resitant E.coli were resistant to four drugs and 25% were resistant to seven; TMP resistance was transferable in 40 of 100 strains tested. The real hazard of such multiple resistance strains is that if the genes for TMP resistance coexist in the same bacterium with genes encoding other resistances, the use of any one of these agents may lead to selection and maintenance of resistance to all the other agents as well. It is not clear from where antimicrobial resistance genes have originated and how multiple determinants for anti microbial resistance accumulate on a given R plasmid. Several studies have shown that the process by means of transposition may play a role in the building of R plasmids especially in hospital environments., Pathetically no agents are available to prevent or interrupt the transposition process selectively and efficiently. Although nalidixic acid may prevent transfer of plasmids, it is yet to be used for this purpose in clinical situations.
In conclusion the present study highlights T-S resistance among E.coli might probably act as a risk factor that would likely to be associated with resistance to other agents which needs further molecular biological investigations.
| Acknowledgement|| |
We are grateful to AstraZeneca Research Foundation India, Bangalore for computerized data compilation and Narsimhamurthy N.S., department of community medicine, MSRMC for assisting in statistical evaluation.
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