The slide centrifuge gram stain as a urine screening method

Area of Science:

• Microbiology
• Clinical Diagnostics
• Urology

Background:

• Bacteriuria, or the presence of bacteria in urine, is a common condition that can lead to urinary tract infections.
• Accurate and rapid detection of bacteriuria is crucial for effective patient management and preventing complications.
• Traditional urine culture methods can be time-consuming, necessitating faster screening techniques.

Purpose of the Study:

• To evaluate the diagnostic performance of a slide centrifuge Gram stain procedure for screening bacteriuria.
• To compare the sensitivity, specificity, and predictive values of the slide centrifuge Gram stain against urine culture results.

Main Methods:

• A slide centrifuge Gram stain was performed on 4161 urine specimens.
• Urine samples were centrifuged, heat-fixed, Gram-stained, and examined under oil immersion.
• Results were compared with urine cultures using two different colony-forming unit (CFU/mL) thresholds (≥100,000 CFU/mL and ≥10,000 CFU/mL).

Main Results:

• Using a ≥100,000 CFU/mL reference, the slide centrifuge Gram stain showed 98% sensitivity, 90% specificity, 99% negative predictive value, and 65% positive predictive value.
• Using a ≥10,000 CFU/mL reference, the screen demonstrated 88% sensitivity, 95% specificity, 96% negative predictive value, and 84% positive predictive value.
• The method proved to be a highly sensitive screening tool for bacteriuria.

Conclusions:

• The slide centrifuge Gram stain is a valuable and sensitive screening method for detecting bacteriuria.
• This technique offers a rapid alternative to traditional urine cultures for initial screening.
• The procedure is particularly effective in identifying the presence of bacteria in urine samples from adult males.