Mid-stream Samples Research Articles

Laboratory diagnosis of urinary tract infections in men

In order to understand the epidemiology and pathogenesis of urinary tract infections in men, as well as to most effectively treat them, it is important to determine the best collection procedures and the most appropriate diagnostic criteria for bacteriuria. Studies by our group and others have begun to define the ways in which the laboratory diagnosis of bacteriuria in men differs from that in women. Future efforts should be aimed at discovering how men develop bacteriuria, how the prostate gland becomes infected, how to more accurately localize bacteriuria in men, and how such infections are best treated. Meanwhile, we offer the following recommendations: o 1. Recognize that guidelines for the laboratory diagnosis of urinary tract infections are derived almost entirely from studies on women, and that these are not always applicable to men. 2. In obtaining voided specimens for culture, meatal cleansing is not necessary, regardless of the man's circumcision status; midstream sampling is preferable, but not mandatory. 3. Culture of voided urine is extremely sensitive and specific for detecting true bacteriuria; bladder specimens are unnecessary unless the patient is unable to void or the voided urine results are difficult to interpret. 4. When bladder specimens are necessary, suprapubic aspiration is preferable to urethral catheterization. 5. The best definition of bacteriuria for voided urine is growth of ≥10 3 cfu/mL of one or two microbial species. 6. The role of the prostatic localization study is unclear, and therefore it should not be performed routinely on men with bacteriuria. 7. In terms of cost, speed, and sensitivity, the Gram-stained smear remains the primary screening procedure for detecting bacteriuria for most microbiology laboratories. 8. In patients with irritative genitourinary symptoms or a positive Gramstained smear, a specimen should be plated on chocolate agar when standard urine cultures are negative.

Is the Clean-Catch Midstream Void Procedure Necessary for Obtaining Urine Culture Specimens From Men?

Abstract To determine whether the results of voided urine cultures in men are affected by meatal cleansing, midstream sampling, or circumcision status, 308 paired (initial and midstream) specimens were collected from 254 urology clinic patients. Half of the patients cleansed their urethral meatus with povidone-iodine prior to voiding. The circumcision status of all patients was noted. The rates of true bacteriuria (growth of 10 4 or greater colony-forming units/ml urine with a single predominant species) and contamination (growth of 10 3 or greater colony-forming units/ml urine with two or more colonial types) were compared in the various collection technique subgroups. Neither the bacteriuria nor contamination rates were significantly different (p > 0.05) in circumcised and uncircumcised patients, or in those who cleansed their meatus and those who did not. Contamination, but not bacteriuria, rates were higher in initial as compared with midstream specimens. These data suggest that the clean-catch midstream void procedure is unnecessary for obtaining routine voided urine culture specimens from men.

Is the clean-catch midstream void procedure necessary for obtaining urine culture specimens from men?

To determine whether the results of voided urine cultures in men are affected by meatal cleansing, midstream sampling, or circumcision status, 308 paired (initial and midstream) specimens were collected from 254 urology clinic patients. Half of the patients cleansed their urethral meatus with povidone-iodine prior to voiding. The circumcision status of all patients was noted. The rates of true bacteriuria (growth of 10 4 or greater colony-forming units/ml urine with a single predominant species) and contamination (growth of 10 3 or greater colony-forming units/ml urine with two or more colonial types) were compared in the various collection technique subgroups. Neither the bacteriuria nor contamination rates were significantly different (p > 0.05) in circumcised and uncircumcised patients, or in those who cleansed their meatus and those who did not. Contamination, but not bacteriuria, rates were higher in initial as compared with midstream specimens. These data suggest that the clean-catch midstream void procedure is unnecessary for obtaining routine voided urine culture specimens from men.

Does discarding the first few millilitres of breast milk improve the bacteriological quality of bank breast milk?

The bacteriology of 20 paired samples of breast milk was analysed to find out if discarding the first few millilitres would reduce the amount of bacterial contamination in breast milk donated to a hospital milk bank. The first sample was the initial 2-3 ml collected from the opposite breast to that first suckled by the baby, and the second was a midstream sample from the same breast. There was no significant difference in the colony counts between the paired samples, and in no instance did the bacterial flora of the second sample differ from that of the first.

Bacteriuria in the puerperium: An evaluation of methods for collecting urine specimens

Five hundred and eighteen puerperal patients were screened for bacteriuria by examination of clean-catch, midstream urine specimens using the dip-slide cultivation technique. Bladder urine from 105 patients showing 104 or more bacteria per milliliter of midstream urine was obtained by suprapubic bladder aspiration and cultivated, along with two consecutive midstream specimens. The bacteriologic results in these specimen categories are compared. Of 23 patients showing growth in the midstream samples compatible with a true bacteriuria, 18 had sterile puncture urine specimens. Consecutive contaminated midstream specimens from the same patient usually yielded growth of the same bacterial species. It is concluded that a diagnosis of bacteriuria in the puerperium cannot be based upon cultural results of midstream specimens alone. In several of the bladder urine specimens, microorganisms being nonpathogenic in the urinary tract and residing normally in the vaginal flore were found, probably due to the traumatic effect of partus. In Oslo the frequency of bacteriuria among women post partum is estimated at a maximum of 1 per cent.

DIAGNOSIS OF URINARY-TRACT INFECTION IN GENERAL PRACTICE

The diagnosis of urinary-tract infection in general practice has been assessed with the aid of suprapubic aspiration and the dip-slide technique. Using a laboratory pour-plate method as the criteria of infection it has been found that a combination of suprapubic aspiration and the dip-slide culture confirmed the presence of infection in 92% of cases, direct microscopy of this suprapubic aspirate in 73%, and culture of a single midstream sample of urine in 72%. Suprapubic aspiration was safe and reliable in general practice, and was tolerated well by patients. It is suggested that the diagnosis of a urinary infection in general practice can best be made by the dip-slide inoculation of a suprapubic aspirate of urine.

A Comparison Between the Bacterial Growth from Milk on Two Different Media and the Somatic Cell Count

SUMMARY The total bacterial count from cow foremilk, midstream and stripping samples after incubation in milk agar at 30°C for 72 hours gave much better agreement with the total somatic cell count of the milk samples than did the amount of bacterial growth on blood agar after incubation at either 30°C for 72 hours, or at 37°C for 48 hours. An increase in bacterial numbers and in somatic cell count at the completion of milking was only found when the bacterial count in milk agar was > 5000/ml.

The occurrence of yeast-like fungi in the urine under normal conditions and in various types of urinary tract pathology.

The frequency of funguria in a normal material and in a material of patients with different types of urinary tract pathology not associated with stasis or bacterial infection was found to be 2.3% and 0.63% respectively. The urine specimens were clean voided midstream samples. When the frequency of funguria in the normal material was redetermined on more satisfactory urine specimens (for women, a catheterized sample, for men, a clean voided midstream sample), funguria was no longer found. Thus, what had seemed to be funguria had been due to contamination by vaginal or fecal flora. In an unselected male clinic material, funguria was found in 29 of 148 patients. The factors that predisposed to funguria in these patients seemed to be the combination of the presence of an indwelling catheter and antibiotic therapy. Patients who had undergone surgery involving coeco-cystoplasty or the creation of a cutaneous uretero-ileostomy were found to have massive funguria post-operatively, which, however, cleared spontane...

A comparative study of a screening test for bacteriuria

Mos T P HY s IC IAN s agree that during pregnancy one has a unique opportunity to unearth quiescent or latent urinary tract disease. An accurate, simple, inexpensive screening test would be ideal. A number of methods have been tried and reported. These include: the Greiss nitrite test, triphenyl-tetrazolium chloride, Gram stain of centrifuged urine specimens, and the agar-coated glass shde method. The Iast two yield more accurate results than the chemical variety of tests but they are time consuming. A paper strip culture technique for obtaining reliable quantitation of bacteriuria has been described.* The following report represents our experience with this technique. Urine samples of 441 consecutive patients were tested with the dip-stick* screening method and concurrent quantitative urine culture. These were done on all new registrants of our obstetrical service. All specimens were clean catch, midstream samples collected in sterile containers. Each sample of urine was promptly cultured by our laboratory as well as being inoculated from the filter strip onto the trays of the screening