Iranian Journal of Medical Microbiology

Study Area, Study Period, and Study Population

Qazvin is the largest city and capital of the Qazvin Province, with 1,300,000 habitants in Iran, which is located northwest of Tehran. This retrospective cross-sectional study was conducted on 3521 patients with and without clinical symptoms of UTI referred to Mehr laboratory, Qazvin, Iran, between April 2017 and January 2019. The age range was between 4 months to 85 years which was classified into seven groups including less than one year, one to ten years, eleven to twenty years, twenty-one to thirty years, thirty-one to forty years, forty-one to fifty years and more than fifty-one years. This study was approved by the Ethical Committee of Qazvin University of Medical Sciences (IR.QUMS.REC.1400.324).

Identification of Bacterial Isolates

Clean-voided midstream urine of the patients was collected into a sterile container (40 ml) and carried to the technical department of the laboratory to be conducted by trained personnel. A 0.01-ml platinum loop was used to inoculate a sheep blood agar and MacConkey agar plate for quantitative culture (Pronadisa media). All plates were incubated at 37°C for 24 h (13, 14). All cultures with equal or greater than 10⁴ colony-forming units (CFU) per milliliter of single or two types of colony pathogen were accepted, and the cultures result in 10²-10⁴ CFU/ml were repeated. A less than 10² CFU/ml was excluded (15). Correlation between UTIs and host characteristics was done using chi-square. Data were analyzed, and statistical comparisons were carried out using SPSS 16.0 (SPSS Inc., Chicago, IL., USA). 

Antimicrobial Susceptibility

Susceptibilities to 9 antimicrobial agents of 5 different classes were determined by the disc diffusion method as described by CLSI guidelines using Mueller- Hinton agar (pronadisa) and commercial antibiotic discs (Mast, Bootle, UK). Bacterial suspensions of 0.5 McFarland (1.5 × 10⁸ colony-forming unit/ ml) were prepared in 0.85% saline solution and passaged onto Mueller-Hinton agar by sterile rayon swabs. Antibiotic discs were dispensed onto the passaged plates. The plates were incubated at 35 °C for 18 hours. The antimicrobial agents were as followes: Amikacin (30 µg), Ciprofloxacin (5 µg), Ceftriaxone (30 µg), Gentamicin (10 µg), Nalidixic acid (30 µg), Nitrofurantoin (300 µg), Trimethoprim/sulfamethoxazole (1.25/23.75 µg), Cephalexin (30 µg), and Erythromycin (15 µg).

UTIs are one of the most prominent common infectious diseases affecting all age groups (16, 17). Escherichia coli is perceived as an etiological agent in the community. Other UTI agents include species of Klebsiella, Proteus, Enterobacter, Staphylococcus, Pseudomonas, Enterococcus faecalis, and Streptococcus (18).
This study was conducted to determine the prevalence of UTIs and antibiotic resistance susceptibility in patients referred to the non-hospital medical Laboratory in Qazvin province. Most of the epidemiological studies in Qazvin province have been conducted on hospitalized patients, while there has not been a study on the prevalence of UTI in a non-hospital medical Laboratory.
In the current study, the overall prevalence of UTIs was estimated at 9.9%. In the present study, Escherichia coli was the most common causative agent with an abundance of 54.5%, followed by Klebsiella pneumonia at 14.1%. Following Pseudomonas aeruginosa with 1.4% was the least prevalent. These results were in line with the results of the study by Elahe Tajbakhsh and Molood Barzan (19-21). In the present study, 81.2% and 18.7% of UTIs were caused by gram-negative and gram-positive bacteria, respectively, which is consistent with a study conducted in 2020 by Zaha et al. They determined that 84.6% and 38.15% of cases were related to gram-negative and gram-positive bacteria, respectively (22).
With more than 60% effectiveness, Nitrofurantoin, Ciprofloxacin, and Gentamicin were the most effective antibiotics against gram-negative bacteria. Similar to our results, in the other studies most of the isolates were sensitive to Nitrofurantoin, Ciprofloxacin, and Gentamicin (23-26). On the other hand, more than 50% of the isolates were resistant to Nalidixic Acid and Trimethoprim/sulfamethoxazole. In the study conducted by Oladeinde et al., and Shahla Mansouri, Nalidixic acid, sulfamethoxazole-trimethoprim, and amoxicillin had the minimum effect on isolated bacteria (27, 28), which was similar to the results of the current study. Among gram-positive bacteria, 69% of the isolates were sensitive to Amikacin which was in accordance with the results of the study conducted by Mihankhah and Farajnia et al. in the years 2017 and 2007 (29, 30).
Associated genes to antibiotic resistance, the genetic association among the resistant species, and reviewing any relationships with patient characteristics are not defined; these are the limitations of this survey.

 

This survey would give us a brilliant clue that antibiotic resistances continue to put the world on a path of tremendous future problems, even in treating urinary infections as a common public health problem. As a result, there is a pressing need to persist in a systematic endeavor to train and encourage prescribers of antibiotics to follow evidence-based prescribing to stem antibiotic overuse resulting in antimicrobial resistance.

 

This work was supported by the Deputy of Research and Technology, Qazvin University of Medical Sciences, Qazvin, Iran. (Grant number: 400000293).

 

None.

Conflicts of Interest

The authors declared no conflict of interest.