Evaluation of etiologic agents and antimicrobial resistance pattern of urinary tract infections in the northwest of Iran

© 2018 The Authors; Tabriz University of Medical Sciences This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Evaluation of etiologic agents and antimicrobial resistance pattern of urinary tract infections in the northwest of Iran

Citation: Habibi-Asl B, Asghari R, Ahangarzadeh Rezaee M, Mohammad-Zadeh A, Abri R. Evaluation of etiologic agents and antimicrobial resistance pattern of urinary tract infections in the northwest of Iran.J Anal Res Clin Med 2018; 6(1): 7-12.Doi: 10.15171/jarcm.2018.002Urinary tract infection (UTI) is still one of the most common infectious diseases all over the world, which engages 150 million individuals of different ages every year which can cause severe and complicated outcomes. 1Various microorganisms can cause UTI, however, its most common agent is Escherichia coli (E.3][4] Due to the proximity of the urethra to the anus and its short length and due to changes in the microbial flora of the vagina at the time of menopause among women, UTI is more common among women than men. 5,6ost often, treatment begins empirically in order to reduce the period of the disease and its complications,; therefore, rapid and accurate identification of the causative agent and selection of a suitable antibiotic are significant in reducing the period of the disease and preventing the spread of infection to other sites. 3,4However, antibiotic resistance of bacteria due to the frequent and improper use of antibiotics have unfortunately caused failure of treatment and an increase in the rates of disability and death, and imposed huge expenses in the field of health. 1 Thus, the empirical therapy of UTI relies on predicting the agents causing infection and knowledge on their antimicrobial susceptibility patterns.However, given that the epidemiology of UTIs and their antimicrobial resistance pattern varies in different regions, therefore continuous evaluation of the incidence of pathogens and antimicrobial resistance in each region is necessary.So, the present study was carried out with the aim to determine the incidence of pathogenic bacteria and antibiotic resistance patterns of the causative uropathogens in the northwest of Iran.
The present cross-sectional analytical and descriptive study was conducted on a total of 56564 non-duplicate midstream urine samples from March 2013 to February 2014.The samples were collected from outpatients with symptomatic UTI submitted to the central laboratory of Tabriz University of Medical Sciences, Tabriz, Iran, then the collected samples were investigated.The patients without a recent experience of taking any antibiotics in the previous sampling were included in the study.
All specimens were cultivated on blood agar and MacConkey agar (Merck, Germany) using calibrated sterile loop technique and incubated at 37 °C for 24 h.Cultures with bacterial counts of ≥ 10 5 cfu/ml or cultures with bacterial counts of ≥ 10 4 and also ≥ 5 white blood cells (WBC) per high-power microscope field of urine sediment were considered as UTIs.The isolated bacteria were identified by standard conventional biochemical tests.
According to the results of antibiogram test, the highest rates of antibiotical resistance were related to ampicillin, cephalothin, and co-trimoxazole with 74.2%, 68.1%, and 54.0%, respectively.In addition, the highest rates of bacterial susceptibility belonged to amikacin, nitrofurantoin, and gentamicin with 79.0%, 77.8%, and 74.5%, respectively (Table 1).
To the best of our knowledge, this study is the most comprehensive report showing the incidence of uropathogens and their antimicrobial resistance pattern among 56564 patients suspected to UTI in the northwest Iran.In the present study, the rate of UTI was only 5.6%.This can be due to the fact that most clinical symptoms of UTI are not specific, and diagnosis of this disease is not carried out with sufficient accuracy; therefore, a definitive diagnosis depends on the outcome of urine culture.In a similar study carried out, Farajnia et al. reported the incidence rate of UTIs as 13.2%. 4The difference between this study and the present one can be attributed to the large sample size of the present study.
In most studies carried out worldwide, E. coli has been referred to as the most common cause of UTI. 7,8In the present study, E. coli with a rate of 68.9% was the most common organism isolated from the urine culture.Other isolated bacteria were respectively Klebsiella spp., Enterococcus spp., Pseudomonas spp., Staphylococcus aureus, Staphylococcus epidermidis, Enterobacter aeruginosa, Citrobacter spp., and Staphylococcus saprophyticus.The order of the pathogens is different in various studies. 9However, most isolated bacteria belong to Enterobacteriaceae family followed by the gram-positive cocci.In this regard, the results of the present study are in agreement with the reports published in other countries. 10Since most bacteria naturally live in the intestine, the urinary tract may be infected in this way. 5Moreover, the number of women with UTI was remarkably higher than men, which is in line with the results of other studies. 5Short urethra and its proximity to the anus are the main causes of increased UTI among women, while the urethra anatomic system among men and secretion of bactericidal material from the prostate play a significant role in preventing such infections. 6ccording to the results of antibiogram test in the present study, the highest rate of antimicrobial resistance was related to ampicillin as 74.2% followed by cephalothin and cotrimoxazole with respectively 54.0% and 68.1%, respectively.In addition, the most bacterial susceptibility belonged to amikacin, nitrofurantoin, and gentamicin with a rate of 79.0%, 77.8%, and 74.5%, respectively.In the previous study in the northwest region of Iran, Farajnia et al. reported that the highest rate of resistance was respectively related to ampicillin, co-trimoxazole, and cephalexin with 90.7%, 51.8%, and 26.5%, respectively.Moreover, the most bacterial susceptibility respectively belonged to amikacin, ciprofloxacin, and gentamicin as 96.6%, 95.1%, and 92.9%, respectively. 4lthough the results show that antibiotic resistance pattern was maintained to some extent, comparing the results of these two studies carried out in two different periods of time indicates an increasing trend in antibiotic resistance.This means that the bacteria have become more resistant to most of the antibiotics except for ampicillin with time.Lack of use of ampicillin in recent years may have caused a decrease in resistance of the bacteria causing UI to this antibiotic.Furthermore, excessive consumption of ciprofloxacin has increased bacterial resistance and decreased the effectiveness of this drug.Moreover, the results of another study conducted in the northwest of Iran by Rezaee and Abdinia showed lower resistance of gram-negative and gram-positive uropathogens to amikacin and then ciprofloxacin, in addition, the most uropathogenic E. coli isolates were susceptible to nitrofurantoin.In addition, the results of this study indicated higher resistance rates to all antibiotics tested especially against third-generation cephalosporins and co-trimoxazole. 11This result is in agreement with present study.According to the results reported by Mukherjee et al., the highest rate of susceptibility was related to nitrofurantoin and amikacin.In addition, the highest rate of resistance belonged to ampicillin, nalidixic acid, cephalexin, amoxicillin, co-trimoxazole, and ciprofloxacin, respectively. 12n another study carried out by Teichman et al. on the resistance of bacteria causing UTI, it was concluded that the isolated bacteria had the highest bacterial resistance to ampicillin and co-trimoxazole as 57.4% and 44.7%, respectively. 13In the study conducted by Chandravathi and Senthilkumaran, amikacin was introduced as a sensitive drug, and ampicillin and ciprofloxacin had the highest rate of bacterial resistance. 14The results of the present study and those of similar studies show that the rate of antibiotic resistance is different in various geographical regions of the world.