Home Print this page Email this page
Users Online: 177
Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
Year : 2020  |  Volume : 9  |  Issue : 2  |  Page : 164-169

Effectiveness of direct interaction and communication with patients, as one preanalytic parameter on reduction of urine culture contamination rate

1 Department of Microbiology, ESI-PGIMSR and ESIC Medical College, Kolkata, West Bengal, India
2 Department of Microbiology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
3 Department of Community Medicine, Medical College Kolkata, Kolkata, West Bengal, India

Date of Submission25-Nov-2019
Date of Decision03-Dec-2019
Date of Acceptance28-Dec-2019
Date of Web Publication9-Apr-2020

Correspondence Address:
Roumi Ghosh
Department of Microbiology, ESI-PGIMSR and ESIC Medical College, Diamond Harbour Road, Joka, Kolkata - 700 104, West Bengal
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijhas.IJHAS_107_19

Rights and Permissions

BACKGROUND: Urine culture contamination is the result of mixing commensal flora of the lower urinary tract during the collection of midstream urine. As patients themselves collect urine sample, urine culture analysis depends on their collection method, which is an important preanalytical issue.
OBJECTIVES: This study was conducted in the Department of Microbiology, Institute of Post Graduate Medical Education and Research and SSKM Hospital, Kolkata, during the month of May and June 2016, with aim to assess the role of communication and verbal instructions explaining “Midstream clean-catch (MSCC) technique” before collection of urine to the adult female outpatients on urine “Culture Contamination Rate” (CCR).
MATERIALS AND METHODS: Three hundred and ninety-six female patients were assigned in one of the two groups: “I” (Instructed) group (n = 196) and “N” (Nothing) group (n = 200). Verbal instructions in local (Bengali) language only provided to the Group “I”. Urine samples were processed in the laboratory. Laboratory technicians and microbiologists were blinded about the groups. Urine culture results were collected from laboratory records.
RESULTS: The CCR in the Group I and Group N was 6.1% and 19.5%, respectively (P < 0.001). Positive culture was observed in 31.6% (62/196) in Group I and 24.0% (48/200) in Group N, which was comparable statistically (P = 0.09). Instruction and communication have been found to be more effective at reduction of urine culture contamination among patients of the age group of 21–30 years (P < 0.001) and lower socioeconomic class (P < 0.001).
CONCLUSIONS: CCR was significantly lower in the group who were provided verbal instruction for MSCC. Thus, proper collection technique may reduce the need of the repeat sample due to contamination and prevent from the unnecessary antibiotic treatment.

Keywords: Contamination rate, instruction for midstream clean catch, preanalytical parameters, urine culture

How to cite this article:
Ghosh R, Khan L, Bhattacharya S, Maiti PK. Effectiveness of direct interaction and communication with patients, as one preanalytic parameter on reduction of urine culture contamination rate. Int J Health Allied Sci 2020;9:164-9

How to cite this URL:
Ghosh R, Khan L, Bhattacharya S, Maiti PK. Effectiveness of direct interaction and communication with patients, as one preanalytic parameter on reduction of urine culture contamination rate. Int J Health Allied Sci [serial online] 2020 [cited 2021 Jan 22];9:164-9. Available from: https://www.ijhas.in/text.asp?2020/9/2/164/282126

  Introduction Top

Urinary tract infection (UTI) in India is one of the common bacterial infections and urine cultures often make up the largest portion of workload for a routine microbiology laboratory. Urine culture is considered the gold standard for the diagnosis of UTI, but difficulty in sample collection and interpretation of inadequately collected specimens may contribute to its misdiagnosis. The standard recommended procedure of urine collection from ambulatory patients is “midstream clean-catch (MSCC) technique” which often leads to contamination of the sample with commensal flora, especially in females. Two key mandatory issues have to be kept as a standard use of appropriate sterile equipment into which the sample is collected and second, the method of collection. A contaminated urine sample not only calls for a repeat sampling but also delays treatment, administration of unnecessary antibiotics with poor consequences, such as patient's grievance, increasing cost of treatment, and the risk of emergence of resistant pathogens.

Preanalytical phase plays an important role in laboratory test result and 32%–75% of all testing errors occur in the preanalytical phase.[1] Essential factors affecting this phase of urine culture include collection techniques, preservation, storage, and transport which affect the accuracy of laboratory diagnosis of UTI.[2],[3]

Purpose of the study

Patients' ability to collect urine sample following MSCC technique is one important pre-analytical parameter. We had provided instructions explaining MSCC technique to the adult female outpatients before collection of midstream urine. Our aim of this study was to assess the effect of counseling and stepwise collection instructions on contamination rate of midstream clean-catch urine (MSCCU) culture among outpatient females. “Culture Contamination Rate” also depicts quality control of laboratory as well as infection control measures followed in hospital. Hence, we also find out the contamination rate of urine culture among female population in a tertiary care hospital from laboratory records.

  Materials and Methods Top

Study design

A cross-sectional experimental study conducted on female patients aged 12–65 years (adults) who visited the Department of Microbiology, Institute of Post Graduate Medical Education and Research and SSKM Hospital, Kolkata, during the months of June and July 2016 for urine culture referred from different outpatient departments with or without any clinical symptoms. The purpose of the study was clearly described and informed written consent was obtained from all participants. The study proposal was approved by the institutional research ethics committee.

Exclusion criteria

  1. Male patients and female of <12 years or >65 years age
  2. Patients already on antibiotic treatment
  3. Patients with a history of urethral discharge or any history of sexually transmitted disease
  4. Patients having urethral instrumentation in the previous 7 days
  5. Patients with known urologic abnormality or nephrolithiasis.

Randomization and group allocation

Patients were randomly allocated to one of the two groups: Group “I” (Instructed) (n = 196) and “N” (Nothing) group (n = 200) using computer-generated randomization list [Figure 1]. The researcher explained the purpose of the test to all patients and provided verbal instructions following a preformed instruction written in local (Bengali) language only to the Group “I” for the collection of MSCC urine sample individually maintaining privacy. Instructions were provided following standard reference [Table 1].[4] Queries of participants were addressed.
Figure 1: Schematic presentation of study method

Click here to view
Table 1: Instructions for collection of midstream clean-catch urine sample

Click here to view

Then sterile urine containers were given to all patients irrespective of the group they fall in to. To minimize possible confounding factor due to lack of knowledge, written instruction charts in local (Bengali) language with pictorial illustrations were pasted on wall of sample collection counter of clinical laboratory services and toilets, which were accessible for all patients.

Urine culture and report interpretation

All the urine samples were transported to laboratory for processing. Samples of both the groups were processed equally following standard methods.[5] The laboratory technician who processed the samples and microbiologists who interpreted the culture results were blind of the groups. Cultures were interpreted after overnight incubation. A “contaminated urine culture” was defined as either (1) growth of ≤104 CFU/mL colony count, (2) growth of ≥3 colony morphology, or (3) growth only urogenital or skin microbiota and reported as insignificant, mixed growth. A “positive urine culture” was defined as growth of one or two pathogenic organisms with count of ≥105 CFU/mL and <105 CFU/mL supported by UTI symptoms and was reported as significant growth and followed by identification and susceptibility testing. No colony on culture media was taken as “no growth.”[5] However, isolated organism's profile and their susceptibility testing were not recorded for this study purpose. Demographic data of the study population were collected on predesigned patient questionnaire.

Statistical analysis

Retrospective data of past 6 months (November 2015 to April 2016) were collected from the bacteriology laboratory record book to find out the contamination rate of female patients' urine samples. We predicted contamination rate of 15% in urine that was obtained after verbal instruction. We estimated a sample size of 190 in each group, based on an α value of 0.05 and a power of 80%. Relative risks (RR) and their 95% confidence interval (CI) for contamination and a positive urinalysis were done using Epi Info (www.cdc.gov/epiinfo). To test for a difference in the contamination rate between the two groups, we calculated Pearson Chi-square (Fisher's exact) test with the help of SPSS 11.0 software (IBM, Chicago, USA). A two-tailed P < 0.05 was considered statistically significant.

  Results Top

A total of 995 urine samples were accepted in the department of microbiology for urine culture during our study period. Among them, 638 samples (64%) were from female patients. In our study, we included 396 female patients who fulfilled the inclusion criteria (age of 16–65 years, without any history of urethral discharge, urethral structural abnormality or instrumentation, and not consumed any antibiotic for UTI) and agreed to participate. Demographic data including age, religion, residence, socioeconomic condition, and literacy status were comparable in both groups (Group “I” and Group “N”). Patients' personal profiles such as marital status, pregnancy, presence of chronic disease, and symptoms of UTI were also comparable in both groups.

The overall rate of contamination among the study population was 12.8% (51/396). The risk for contamination in instructed group (Group I) was 6.1% (12/196) compared with 19.5% (39/200) in noninstructed group (Group N) [RR: 0.31; 95% CI: 0.17–0.58; [Table 2]. There was a statistical association (P = 0.001) by Fisher's exact test in the contamination rate of these two groups. Growth of ≥3 types of colonies is the most frequent mode of culture contamination in our study in both the groups (41.6% of Group I and 53.8% of Group N) [Figure 2]. Positive culture was observed in 31.6% (62/196) of female in Group I and 24.0% (48/200) of female in Group N, which was comparable statistically (P = 0.09, Fisher exact test; OR: 1.46, 95% CI: 0.94–2.28) [Table 2].
Table 2: Rate of contamination and culture results among study groups

Click here to view
Figure 2: Types of culture contamination among study groups: Contamination type 1: Growth of urogenital or skin flora, Contamination type 2: Growth ≤104 CFU/ml colony count, Contamination type 3: Growth of ≥3 types of colonies grown at any quantity

Click here to view

We have analyzed the impact of providing instruction for MSCC collection in different subgroups of our study population, for example, age groups, groups according to educational level, socioeconomic status, marital status, pregnancy status, addiction habit, and presence of chronic disease. As the data in [Table 3] shows, by doing univariate analysis, “instruction and communication” have been found to be more effective at reduction of urine culture contamination among patients belong to age group of 21–30 years (P < 0.001) or who were married (P < 0.001), not pregnant (P < 0.001), with no history of addiction (P < 0.001), no history of chronic disease (P < 0.001), and having symptomatic UTI (P < 0.001).
Table 3: Rate of contamination among study groups according to different variables

Click here to view

Multivariate logistic regression points out “providing instruction for MSCC” as single most important predictor of noncontamination (adjusted OR = 4.160, CI = 2.053–8.426) when a model is constructed combining all the factors mentioned above along with “providing instruction for MSCC” [Table 4].
Table 4: Multiple logistic regression showing predictors of contamination (n=396)

Click here to view

Another multivariate logistic regression model was constructed among those whom the instruction was given to find out the predictors of noncontamination which will act as a proxy indicator of the factors which would help the instructions to be more effective. It shows “groups having symptomatic UTI” as a significant predictor (P = 0.032, adjusted OR = 6.475) [Table 5].
Table 5: Multiple logistic regression showing predictors of contamination among whom intervention was taken (n=196)

Click here to view

  Discussions Top

Providing appropriate medical diagnosis and efficient patient care could only be done by good quality control of clinical laboratory methods, and preanalytical phase is an important component of it. This fact holds true for diagnosis of UTI, which used to affects approximately 10% of humans at some point during their lives. A report from different institutions of the USA showed rate of urine culture contamination among outpatients varied from 5.6% to 36.8%.[2] However, studies to identify and evaluate preanalytic practices associated with urine specimens and to assess their impact on the result of urine culture in microbiology are largely missing from this part of world. In this randomized trial, we observed that females who were randomly assigned to receive instruction for MSCC technique for sample collection had lower rates of contaminated urine specimens. A statistically significant association (P = 0.001) was found among the two groups regarding the contamination rates. Similar result was observed by one earlier study, which had clearly shown contamination rate and colony counts in no-instruction group were far higher than those in any of the groups receiving precollection instructions (P < 0.0001).[6] Another study on adult patients revealed a significant reduction in contamination rate by urogenital cleaning with soap paper (27.9% to 13%).[7] Our result is comparable to the finding of Vailllancourt et al., who had revealed 7.8% of reduction rate among toilet-trained children in the group who had done cleaning before collection.[8] One strikingly different observation was reported that no consistent difference in contamination rate from midstream samples without any instruction and clean-catch samples after instructions.[9],[10] Although, a meta-analysis did not find any difference in contamination between midstream urine specimens collected with or without perineal cleansing from adult female patients, cleansing before MSSU collection has been recommended with sufficient evidence.[2]

The urine culture contamination rate (CCR) in our combined study population was 12.8%. When we calculated our laboratory data of previous 6 months, around 14.3% of (536/3749) urine samples from female patients were reported as mixed bacterial growth and ordered to be repeated due to doubtful significance or gross contamination. This finding is similar to the finding of previous study from Chandigarh, India, who found around 17% urine culture contamination in their laboratory among female patients (28.33% in total).[11] Our data also corroborate with a prospective study done in Nepal, who had found contamination rate of 12.66%.[6] Varying estimates of the contamination rate have been shown in different studies, as it depends on many factors such as age group, education level, maintenance of hygiene, laboratory transport, and contamination which is always higher among females as compared to males.[2],[7]

We have included only adult female patients between 12 and 60 years of age, and after statistical analysis, we found that statistically significant reduction in contamination rate only among the patients of the age group of 21–30 years. Verbal instruction did not help to reduce contamination among pregnant females. Urine CCR during pregnancy was also found to be similar for urine collected by nonclean-catch and clean-catch technique in other studies.[2],[8] Physical changes in the lower urinary tract during pregnancy might be the cause of urine stagnation which hampers proper collection of clean-catch urine. Our culture contamination significantly decreases among symptomatic females in Group I in comparison to Group N. This result is contradictory to the previous randomized controlled trial on female with dysuria which showed identical contamination rate in both “no precaution” group and MSCC group.[10] Our patients with complaints of increased frequency, urgency, and burning micturition have been benefited by instructed MSCC technique.

Thus from the results, it can be thoroughly concluded that spoken instructions before the collection of MSCCU to individual female ambulatory patients do have a positive effect on reducing the sample contamination rate in this population. In a highly populated country such as India, where we find a paucity of workforce, money, time, labor, and adequate patient instruction can help to alleviate all these factors. Moreover, the main bulk of the population belonged to the lower middle class strata and also resided in rural areas for whom the monetary cost, transportation, and accessibility of healthcare are mammoth problems. By reducing the contamination rate among them, we also strive to save them from unnecessary hazards and speed up the diagnosis and hence the treatment. It has also good impact on increasing burden of antimicrobial resistance by promoting appropriate and judiciary antibiotic usage. The extra edge of this approach is to provide some health information to the patients which is lacking in our country. By motivating our health-care workers in the collection centers to deliver careful instruction before urine collection in hospitals can improve urine culture reporting quality. Previous studies had also pointed out some significant and essential factors affecting the preanalytic phase of urine culture, such as proper techniques for urine collection, preservation, storage, and transport which are helpful to increase accuracy of laboratory diagnosis of UTI.[2] We should incorporate all these good laboratory and clinical practices for a speedy and accurate diagnosis.

However, further study of larger cohort with proper control of other preanalytical variables needs to be done to assess the impact of verbal instructions, its feasibility, convenience, and acceptance. Availability of female staff for communication with the patient, maintenance of privacy during instruction, availability of soap and water in toilet, and time constraints are the main challenges in government hospital setup to apply this method.

Limitations of the study

The knowledge and communication skills of the collection center staff were not studied. Therefore, how they actually deliver the instructions to the patients in absence of supervision is beyond scope of this study.


Authors thank ICMR for providing opportunity to perform this study by granting Short-term Studentship, 2017.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Stankovic AK, DeLauro E. Quality improvements in the preanalytical phase: Focus on urine specimen workflow. MLO Med Lab Obs 2010;42:20, 22, 24-7.  Back to cited text no. 1
LaRocco MT, Franek J, Leibach EK, Weissfeld AS, Kraft CS, Sautter RL, et al. Effectiveness of preanalytic practices on contamination and diagnostic accuracy of urine cultures: A laboratory medicine best practices systematic review and meta-analysis. Clin Microbiol Rev 2016;29:105-47.  Back to cited text no. 2
Delanghe J, Speeckaert M. Preanalytical requirements of urinalysis. Biochem Med (Zagreb) 2014;24:89-104.  Back to cited text no. 3
Tille PM. Bailey & Scott's Diagnostic Microbiology. 13th ed. St. Louis, Missouri: Elsevier; 2014. p. 919-30.  Back to cited text no. 4
Church DL. Urine culture (aerobic bacteriology). In: Garcia LS, editor. Clinical Microbiology Procedures Handbook. 2nd ed., Vol. 3, Ch. 10. Washington, DC: ASM Press; 2007. p. 1-27.  Back to cited text no. 5
Fisher LA, Johnson TS, Porter D, Bleich HL, Slack WV. Collection of a clean voided urine specimen: A comparison among spoken, written, and computer-based instructions. Am J Public Health 1977;67:640-4.  Back to cited text no. 6
Shrestha R, Gyawali N, Gurung R, Amatya R, Bhattacharya SK. Effect of urogenital cleaning with paper soap on bacterial contamination rate while collecting midstream urine specimens. J Lab Physicians 2013;5:17-20.  Back to cited text no. 7
[PUBMED]  [Full text]  
Vaillancourt S, McGillivray D, Zhang X, Kramer MS. To clean or not to clean: Effect on contamination rates in midstream urine collections in toilet-trained children. Pediatrics 2007;119:e1288-93.  Back to cited text no. 8
Schneeberger C, van den Heuvel ER, Erwich JJ, Stolk RP, Visser CE, Geerlings SE. Contamination rates of three urine-sampling methods to assess bacteriuria in pregnant women. Obstet Gynecol 2013;121:299-305.  Back to cited text no. 9
Lifshitz E, Kramer L. Outpatient urine culture: Does collection technique matter? Arch Intern Med 2000;160:2537-40.  Back to cited text no. 10
Appannanavar SB, Biswal M, Rajkumari N, Mohan B, Taneja N. Evaluation of commercial boric acid containing vials for urine culture: Low risk of contamination and cost effectiveness considerations. Indian J Pathol Microbiol 2013;56:261-4.  Back to cited text no. 11
  [Full text]  


  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Materials and Me...
Article Figures
Article Tables

 Article Access Statistics
    PDF Downloaded31    
    Comments [Add]    

Recommend this journal