Week 9 Project Assignment Due November 23 At 10:59 Pm Review

Week 9 Projectassignmentdue November 23 At 1059 Pmreview Sheetbased O

Based on your knowledge from the lab manual readings from this week, create a 2- to 3-page document in Microsoft Word for providing answers to questions in the following review sheets: Week 9 Review Sheet Submission Details: Support your responses with examples. Cite any sources in APA format. Name your document SU_BIO2071_W9_A2_LastName_FirstInitial.doc. Submit your to the Sdocumentubmissions Area by the due date assigned.

Week 9 – Review Sheet Exercise 5 - Urine Culture Techniques

  1. What is bacteriuria? When is it significant?
  2. How do microorganisms enter the urinary tract?
  3. Why is aseptic urine collection important when cultures are ordered?
  4. List five bacteria that can cause urinary tract infection.
  5. If you counted 20 colonies from a 0.01-ml inoculum of a 1:10 dilution of urine, how many organisms per milliliter of specimen would you report? Is this number significant?

Paper For Above instruction

Bacteriuria refers to the presence of bacteria in the urine. It is considered significant when bacteria are detected in quantities sufficient to suggest a urinary tract infection (UTI). Typically, the presence of ≥10^5 colony-forming units (CFU) per milliliter of urine indicates bacteriuria that is clinically significant, especially when accompanied by symptoms of infection such as dysuria, urgency, or flank pain (Nicolle, 2017). However, lower counts may also be significant in symptomatic individuals or those with catheter-associated UTIs, necessitating clinical correlation (Kotlowski & Hughes, 2019).

Microorganisms can enter the urinary tract through several routes. Most commonly, bacteria ascend from the urethral opening into the bladder. This is facilitated by factors such as poor hygiene, sexual activity, or anatomical anomalies (Hooton et al., 2019). Hematogenous spread, where bacteria disseminate via the bloodstream, is less common but can occur, especially with systemic infections. Additionally, iatrogenic introduction during medical procedures like catheterization can introduce bacteria directly into the urinary tract (Flores-Mireles et al., 2015).

Aseptic urine collection is crucial when culturing urine because contamination can lead to false-positive results, which may result in unnecessary antibiotic treatment. Proper collection techniques—such as midstream clean-catch or sterile catheterization—reduce contamination from skin flora or environmental microbes. This ensures that the bacteria identified truly originate from the urinary bladder, facilitating accurate diagnosis and appropriate management (Muder & Brennen, 2020).

Five bacteria commonly associated with urinary tract infections include:

  • Escherichia coli: The most prevalent cause of UTIs, accounting for up to 80% of cases (Foxman, 2014).
  • Proteus mirabilis: Known for its urease activity, which can lead to stone formation (Khan et al., 2019).
  • Klebsiella pneumoniae: Frequently involved in complicated UTIs and often multidrug-resistant (Vu et al., 2021).
  • Enterococcus faecalis: Common in hospital-acquired UTIs, especially in catheterized patients (Cai et al., 2020).
  • Pseudomonas aeruginosa: Noted in nosocomial infections and those in immunocompromised patients (Kim et al., 2018).

To determine the bacterial load in urine, consider the colony count from a culture. If 20 colonies are observed from a 0.01-ml inoculum of a 1:10 dilution, the calculation of organisms per milliliter is as follows:

The original urine specimen's bacterial concentration can be estimated using the formula:

Number of colonies × reciprocal of the dilution factor × 100 (to convert to per ml)

Thus, 20 colonies × 10 (dilution) × 100 = 20,000 CFU/ml.

This number exceeds the typical threshold of 10^5 CFU/ml, indicating significant bacteriuria. Therefore, the result suggests a likely urinary tract infection, especially if correlated with clinical symptoms (Nicolle, 2017).

References

  • Cai, T., Hu, Y., & Xie, L. (2020). Enterococcus faecalis in urinary tract infections: Pathogenic mechanisms and antimicrobial resistance. Journal of Clinical Microbiology, 58(8), e00930-20.
  • Flores-Mireles, A. L., Walker, J. N., Caparon, M., & Hultgren, S. J. (2015). Urinary tract infections: Epidemiology, mechanisms of infection and treatment options. Nature Reviews Microbiology, 13(5), 269-284.
  • Foxman, B. (2014). Urinary tract infection syndromes: Occurrence, recurrence, bacteriology, risk factors, and disease burden. Infectious Disease Clinics of North America, 28(1), 1-13.
  • Hooton, T. M., Bradley, S. F., Cardenas, D. D., et al. (2019). Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: CDC guideline for prevention of catheter-associated urinary tract infection. Clinical Infectious Diseases, 68(8), e45-e64.
  • Khan, S., Mahapatra, S. S., & Karmakar, P. (2019). Proteus mirabilis in urinary tract infections: Pathogenesis and resistance. Current Microbiology, 76(2), 211-220.
  • Kim, J. H., Kim, H. S., & Song, J. H. (2018). Pseudomonas aeruginosa urinary tract infections: Clinical features, resistance, and management. Journal of Medical Microbiology, 67(4), 480-489.
  • Kotlowski, C., & Hughes, J. (2019). Assessment of bacteriuria: Significance and clinical considerations. Urology Reports, 7(2), 69-73.
  • Muder, R. R., & Brennen, C. (2020). Urine culture contamination: Implications for diagnosis and antimicrobial stewardship. Infection Control & Hospital Epidemiology, 41(6), 631-632.
  • Nicolle, L. E. (2017). Urinary tract infections in older adults. Clinical Geriatrics, 25(2), 22-26.
  • Vu, T. T. T., et al. (2021). Multidrug-resistant Klebsiella pneumoniae in urinary tract infections: Epidemiology and resistance mechanisms. Frontiers in Microbiology, 12, 677917.

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