Genital region cleansing wipes : Effects on urine culture contamination

Introduction: Urine culture is the gold standard test for revealing the microbial agent causing urinary tract infection (UTI). Culture results are affected by sampling techniques; improper sampling leads to contamination of urine and thus contamination of the culture with urogenital flora. We aimed to evaluate the effect of urogenital cleansing, performed with chlorhexidine-containing genital region cleansing wipes (GRCW) on contamination rates. Methodology: A total of 2,665 patients with UTI-related complaints and with urine culture requests from various outpatient clinics were enrolled in the study. Of the patients, 1,609 in the experimental group used GRCW before sampling, while 1,046 in the control group did not use any wipes. Results: The contamination rate in the experimental group patients was 7.7%, while it was 15.8% in the control group. Contamination rates were significantly higher in the control group than in the experimental group for both women and men. Contamination rates for children and adults were also significantly lower in the experimental group than in the control group. Conclusions: Our study, conducted in a large population, showed that the use of chlorhexidine-containing cleansing wipes significantly reduced urine culture contamination rates in both genders, in both child and adult age groups. Using GRCW, collection of urine after urogenital area cleansing will decrease the contamination problem.


Introduction
Urinary tract infection (UTI) is one of the most common infections among both inpatients at hospitals as well as in the community.About 10% of the human population has had at least one UTI during their lifespan.Urine culture is accepted as the gold standard test for the diagnosis of UTI.In most cases, properly collected midstream urine (MSU) samples, which contain more than 10 5 colonies per milliliter, indicate infection [1][2][3].For appropriate treatment of infection, isolates must be identified and antibiotic resistance must be known.However, inappropriate collection of urine samples may cause contamination of a sample with urogenital skin flora.Contamination, may lead to problems during interpretation and reporting of culture results.Even though direct MSU collection is still the most common method, various levels of contamination rates in urine samples have been reported in various studies [4][5][6][7][8].In cases of contamination, resampling from patients is required.Therefore, contamination reports delay diagnosis, increase laboratory workload, and cause unnecessary antibiotic use and development of resistant pathogens.Repetitive urine cultures increase the total cost of the tests and harm an institution's reliability [9,10].
In this study, patients admitted to outpatient clinics of our tertiary stage hospital and for whom urine cultures were requested were included.The effect of urogenital cleaning with chlorhexidine-containing genital region cleansing wipes (GRCW) on urine culture contamination rates was evaluated.Various methods for decreasing contamination rates have been examined in previous studies [5,6,8,9,11].However, in our literature search, no study evaluating contamination rates of urine culture after using GRCW was found.Another important aspect of our study is the use of a quite large population, which makes it more reliable.

Sample collection
Patients admitted to the pediatrics, urology, emergency, internal medicine, infectious diseases, and obstetrics and gynecology outpatient clinics with UTI complaints between 1 December 2015 and 1 May 2016 were selected.Of these patients, 2,655 for whom urine culture was requested were included to the study.All patients were asked for MSU sampling according to the instructions, which were given as leaflets prepared by the laboratory (two different leaflets for two groups).Parents of the pediatric patients were informed.A total of 1,609 (60.6%) randomly selected patients (experimental group) used GRCW (Destimal Saglik Kozmetik San.Tic. Ltd.Sti., Istanbul, Turkey) before sampling, and the remaining 1,046 (39.4%) control patients did not use any wipes.They only used soap and water per the instructions given by the laboratory.Patients who had used antibiotics within seven days were not included to the study.A random sampling method was used for choosing experimental and control patients.The GRCWs used in this study were chlorhexidine-containing, cheap, portable, and easy-touse wet wipes that do not require soap, water, or any other cleaning material.The local ethics committee approved the study design (05 November 2015/41, 1491-119-15/1539), and written informed consent was obtained from patients who participated in this study.

Culture
Collected urine samples were inoculated on 5% sheep's blood agar and eosin-methylene blue agar (Salubris Inc., Istanbul, Turkey); petri dishes were incubated at 37°C for 18-24 hours in aerobic conditions.Reporting of the cultures was performed based on the American Microbiology Society guidelines [12].Samples were reported as no growth if no colonies were detected on the petri dishes after 18-24 hours [12].Samples were reported as contaminated if three or more colonies (mixed growth) were detected containing low levels (< 10 4 CFU/mL) of microorganisms found on the skin or urogenital flora.In this case, another sample for culture was requested from the patient.Detection of one or two microorganism species totaling > 10 5 CFU/mL colonies or totaling < 10 5 CFU/mL colonies but with UTI symptoms led to further evaluation.Isolated microorganisms were identified using conventional biochemical tests and they were confirmed using the automated identification system VITEK 2 (BioMerieux, Marcy l'Étoile, France).Lastly, microorganisms were reported along with colony counts and antibiotic resistance results.

Statistical analyses
All data were analyzed using SPSS 16.0 (Statistical Package for Social Sciences) for Windows (IBM, Armonk, USA).Contamination rates were calculated using Pearson's Chi-squared test for statistical analysis, and the decrease in contamination was calculated using a logistic regression test.P < 0.05 were accepted as statistically significant.

Results
In this study, 2,655 patients admitted to the pediatrics, urology, emergency, internal medicine, infectious diseases, and obstetrics and gynecology outpatient clinics were included.Of these patients, 71.6% (n = 1,901) were women, while 28.4% (n = 754) were men; 17.5% (n = 465) were children between 5 and 14 years of age, while 82.5% (n = 2,190) were adults over 15 years of age.
There was significant difference (p = 0.0001) (Table 1) in contamination rates between the experimental group of patients who used GRCW (7.7%, n = 124) and the control patients (15.8%, n = 165).GRCW use decreased the contamination rate 2.243 times (p = 0.0001; odds ratio = 2,243; confidence interval = 1.751-2.872).Contamination rates were 8.8% (n = 105) for female and 4.6% (n = 19) for male patients in the experimental group and 17.7% (n = 125) for female and 11.8% (n = 40) for male patients in the control group (Table 1).Contamination rates for both male and female patients were significantly higher in the control group than in the experimental group (p = 0.0001).
A total of 465 children between 5 and 14 years of age were included in the study.Contamination rates were significantly lower (p = 0.03) among children in the experimental group (8.7%, n = 27) than in the control group (14.2%, n = 22).Contamination rates were also significantly different among 2,190 adult patients (p = 0.0001): 7.5% (n = 97) for adults in the experimental group and 16.1% (n = 143) in the control group (Table 1).

Discussion
UTIs emerge after pathogenic microorganisms affect urinary system organs such as the urethra, bladder, kidney, or prostate.Detection of > 10 5 CFU/mL growth indicates infection in a properly collected MSU sample.Urine may become contaminated with skin or distal urethral flora in both genders.There is an additional contamination risk for women with perineal and vaginal flora [3].Various definitions have been used for urine culture contamination by researchers [5,6,8,9,11].
In our study, urine culture contamination was defined as contamination of urine sample with growth of microorganisms < 10 4 CFU/mL of the skin or urogenital flora or mixed growth of three or more microorganism species.Changing levels of contamination have been demonstrated in various studies [5,8,11,13].Reported variances among these studies may be attributed to the contamination definition, sample collection, and transport methods, as well as differences in study populations.
Valenstein et al. [7] reported a contamination rate of 20.6% in women and 9.5% in men.However, Shrestha et al. [9] reported contamination rates of 12.7% in women and 2.8% in men.These differences between genders, which have also been confirmed in our study in both groups, may be caused by the anatomical and hormonal differences among male and female urogenital systems.Saez-Llorens et al. [5] and Lohr et al. [14] compared the MSU sampling techniques in children in their studies.However, both of these studies failed to demonstrate the effect of washing the genital area on reducing contamination rates.
Vaillancourt et al. [15] showed a significant decrease of contamination rates of MSU samples collected from children who used wipes and liquid soap.MacDonald et al. [6] found that chlorhexidine decreased contamination rates in 62 sick babies between 1 and 24 months of age, but found that the use of chlorhexidine was not cost effective.In another study, Baerheim et al. [8] investigated perineal area cleaning with 111 healthy women between 19 and 40 years of age.Opening the labia to prevent contact with urine during sample collection decreased contamination significantly, while cleaning the perineal area with wipes humidified only with water had no effect on decreasing contamination risk.Jackson et al. [4] showed that the use of a urine collection device decreased contamination rates in a study conducted on 2,182 female patients.In another study, Lifshitz et al. [16] reported no significant decrease in 242 female outpatients who used cleaning wipes containing benzalkonium before MSU collection.
In our study, contamination rates were found to be significantly decreased in the experimental group compared to the control group among children.The results were also similar in adults.These data clearly show that cleaning the urogenital area, especially with GRCW containing chlorhexidine, decreases contamination rates in urine culture.
In the present study, indications for sampling urine seem to be a weakness of the study; however, this condition is valid for both study groups, and the presence of randomization eliminates this limitation.
No study was found in our literature search that used GRCW to decrease contamination rates.Moreover, our study was performed on a large population, while the other studies targeted limited groups.

Conclusions
Contamination of urine culture is a common problem in routine bacteriology laboratory practice.Even though patients were notified verbally about how to collect urine samples and given leaflets prepared by our laboratory showing instructions for MSU collection, the collection of the MSU samples by the patients was still questionable.Contamination of urine culture increases total test costs due to repetitive cultures, loss of patient confidence in healthcare institutions, unnecessary prescription of antibiotics, and increase in drug-resistant pathogens.Data acquired from our study, which is focused on the contamination rates of urine culture of a large patient population, clearly demonstrates the applicability, efficiency, and acceptability of the method.Collection of MSU after urogenital area cleansing will decrease the contamination problem, which is a major issue of urine cultures.Further cost analysis studies can demonstrate the economic profit provided from the elimination of unnecessary culture repeats and antibiotic use.

Table 1 .
Change of contamination rate between the groups that used (n = 1,609) and did not use (n = 1,046) genital area cleaning wipes based on gender and age.