Year : 2009 | Volume
: 20 | Issue : 2 | Page : 251--253
Antimicrobial susceptibility pattern of urinary tract pathogens
Zakieh Rostamzadeh Khameneh, Ali Taghizadeh Afshar
Department of Microbiology, Medical Sciences University of Urmia, Iran
Zakieh Rostamzadeh Khameneh
Department of Microbiology, Medical Sciences University of Urmia, Urmia
Microbial drug resistance is a major problem in the treatment of infectious diseases worldwide. The purpose of this survey is to determine the prevalence of the type of bacterial agents that cause urinary infection and to assess the antimicrobial sensitivity pattern in the Urmia Medical University, Iran. In the period between 2005 and 2006, urine cultures collected were analyzed. Positive culture was defined as growth of a single bacterial species with colony count of > 100,000 CFU/mL. Stratification was done according to age-group and gender. Statistical tests used included chi-square to evaluate differences between susceptibility rates. A total of 803 urine culture positive patients were studied of whom 81.6% were females and 18.4% were males. The common micro-organisms isolated were E. coli (78.58%), Klebsiella (5.48%), Proteus and Staphylococcus. About 89% of the E. coli isolated showed sensitivity to cephtizoxin, 83.9% to gentamycin and 83.2% to ciprofloxacin; the highest resistance was shown to ampicillin and cotrimoxazole. Surveys of this nature will give a clear idea about the bacteriologic profile in a given institution as well their antibiotic sensitivity profile. This will act as a guide to commencing empirical antibiotic treatment in patients with urinary infections until such time culture reports are available.
|How to cite this article:|
Khameneh ZR, Afshar AT. Antimicrobial susceptibility pattern of urinary tract pathogens.Saudi J Kidney Dis Transpl 2009;20:251-253
|How to cite this URL:|
Khameneh ZR, Afshar AT. Antimicrobial susceptibility pattern of urinary tract pathogens. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2022 Jan 19 ];20:251-253
Available from: https://www.sjkdt.org/text.asp?2009/20/2/251/45573
With the advent of newer and powerful antibiotics, the medical society was hopeful to be able to manage microbial infections more effectively. In the initial few years, advances made in life style changes, diagnostic techniques as well as hygienic level of the society, resulted in a significant reduction in the prevalence of infectious diseases worldwide.  The microbes that continued causing infections despite usage of these newer antibiotics represented a new form of infectious diseases caused by drug resistance. It is expected that in course of time, microbes will become more resistant because of their new mutants.  Urinary tract infections are the second most common infections after infections of the respiratory tract,  and constitute a great proportion of prescription of antibiotics. Antibiotic treatment that are of duration shorter than required, and also treatment administered without considering the microbiologic and antibiotic sensitivity data result in more resistance in bacterial strains. Antibiotic resistance patterns vary in different areas.  In order to apply an appropriate therapeutic strategy in each region, we must have data on the most common pathogens and also their sensitivity to different antibiotics. This study was undertaken to study these data in the Urmia Medical University, Iran
Materials and Methods
This descriptive study was performed on 803 patients with urinary tract infections referred to a laboratory attached to the Urmia Medical University, Iran during the years 2005 and 2006. Urine samples were collected according to the midstream method and in sterile containers. We cultured them on blood agar and EMB environments. After 24-hours incubation at 37 degrees Celsius, the colonies were counted and samples with colony count more than 100,000/mL were considered positive. A confirmation test was performed for identifying the organism. The sample was then cultured in muler Hilton bras environment (antimicrobial sensitivity test). The disc diffusion test (using Kirby-baur method) on muler Hilton agar was used to assess the sensitivity pattern. After incubation and diameter measurements, we determined the growth rate of the sensitive, semi-sensitive and resistant micro-organisms. The data were analyzed by Spss software.
A total of 803 patients were studied of whom, 81.6% were female (655) and 18.2% were male. Most of the study patients were more than 35-years of age. Overall, E. coli was the most common micro-organism isolated in all age-groups and both sexes followed by Klebsiella and Proteus [Table 1]. No significant difference was found between the bacteria isolated and age of the patients (p > 0.05). E. coli showed higher sensitivity to ceftizoxim (89.54%), gentamycin (83.9%), ciprofloxacin (83.2%) and greater resistance to ampicillin and co-trimoxazole [Table 2].
Klebsiella strains showed high sensitivity to ciprofloxacin and gentamycin. The most effective drugs for pseudomonas were amikacin and ciprofloxacin. Staphylococcus strains were more sensitive to vancomycin, gentamycin and ciprofloxacin.
Our results demonstrate that drug resistance of E.Coli to many antibiotics is high with the maximum prevalence of resistance being to drugs that have been used for a long time, such as ampicillin and co-trimoxazole. Our results are similar to one other study that has been conducted in Iran. They have reported E. Coli resistance to ampicillin of 96.8% and to cotrimoxazole of 70%;  however, the surveys conducted in Russia  and Argentina  have shown relatively lesser resistance. The results of our study about co-trimoxazole are similar to results of a survey conducted in Holland,  but the drug resistance of E.Coli has reduced from 79% to 62% over the last few years in that country. Partial resistance of E. Coli to ampicillin and co-trimoxazole has been reported in a survey from the USA,  which is less than the prevalence in our study. We also found less drug resistance of E. Coli to nitrofurantion and nalidix acid in comparison to ampicillin and co-trimoxazole.
A survey conducted by Chritiaens and colleagues  has demonstrated that Staphylococcus saprophyticus (9%) and Proteus (4%) were the main organisms isolated, after E. Coli. Our results are different from results of that survey. A survey conducted by Papapetropoulon and colleagues  on germ-negative bacilli has demonstrated the prevalence of Proteus to be 10% and Klebsiella to be 8.7%. A study from Brazil has reported the prevalence of E. Coli to be 71.6%, Klebsiella to be 6.4% and Proteus to be 6.1%. 
E. Coli is the most common micro-organism causing urinary tract infection in both men and women of all age-groups. It is still sensitive to many drugs, but this is getting reduced each year to some commonly used drugs because of empirical use. Surveys conducted in different parts of Iran and on different patient-groups with urinary tract infection, have demonstrated that many of E. Coli strains are still sensitive to nalidixic acid. The prevalence of this sensitivity varies from 73 to 78%. In the USA and other Western countries, the sensitivity is higher and less than 5% of E. Coli strains are resistant to this drug.  In our study, the sensitivity was less than the other surveys, both in Iran and other parts of the world, and the absolute resistance of E. Coli to nalidixic acid was very low. Klebsiella, the second most common micro-organism in our study, showed a high degree of sensitivity to nalidixic acid. Therefore, we can use nalidixic acid as an appropriate drug for treatment of urinary tract infections, but we should note that 36% of the E. Coli strains had partial resistance to this drug and irrational prescriptions may cause higher resistance to nalidixic acid in the future.
|1||Carlos RK, Caio M, Carmen PO. Antibiotic resistance and trend of urinary pathogens in general outpatients from a major urban city. Int Braz J Urol 2007;33:42-9.|
|2||Orrett FA, Shurland SM. The changing patterns of antimicrobial susceptibility of urinary pathogens in Trinidad. Singapore Med J 1998;39(6):256-9.|
|3||Mandel G, Bennett JE, Dolin R. Principles and practice of infection disease. 5t h ed. Churchill Livingstone; 2000; 773-805.|
|4||Doton TM. A simplified approach to urinary tract infection. Hosp Pract 1995;332(1):21-8.|
|5||Falahatkar S Sobhani M, Ghilpour H. Urinary tract infection in spinal cord transected war. Arch Iran Med 2000;13(3):133-5.|
|6||Stranchunskii LS, Sckhin SV, Abramova ER. Antibacterial drug resistance of gram negative agents causing urinary tract infection in female in Russia. Ter Arku 2000;72(6):30-5.|
|7||Rossl A, Tokumotto M, Gales M. Monitoring of antibiotic resistance in Argentia. Panam Salud Pub 1999;6(4):234-41.|
|8||Vromen M, Vanderven AJ, Konls A. Antimicrobial resistance patterns in urinary tract infection isolated from nursing home residents. J Antimicrob Chemother 1999;44(1):113-6.|
|9||Dyer IE, Sankary TM, Dawson IA. Antibiotic resistance in bacterial urinary tract infections. West J Med 1998;169(5):265-8.|
|10||Chiristiaens TH, Heytehis S, Vershraegen J. Which bacteria are found in Belgian woman uncomplicated urinary tract infection? Acta Clin Belg 1998;511:184-8.|
|11||Papapertropoulou M, Pagonopoulou O. Prevalence and sensitivity to antibiotic of Entreobacteriaceae isolated from urinary cultures in some microbiology laboratorieses of acity in west Greece. Pathol Biol 1997;45:716-20.|