Occasionally, organ-isms such as Serratia marcescens, Mima-Herellea, Candida albicans, and even Cryptococcus neo-formats may be significant and produce disease in diabetics and in patients treated with corticosteroids and immunosuppressive agents. Dips-steroids, Staphylococcus epidermidis, and micro-aerophilic streptococci are highly suspect as contaminants. Microscopic Methods. Rapid diagnostic meth-ods are available by either preparation of a Gram stain of unsedimented urine and examination with' an oil immersion lens, or by the study of the centrifuged urinary sediment for bacteria, employ-ing the high dry objective under reduced light with or without the addition of methylene blue.
MICROBIAL DISEASES bacteriuria regardless of the number of organisms found, providing that the specimen is not contaminated prior to culture. Bacteriologic Findings and instrumentation of the urinary tract. Enterobacteriaceae are by far the most common organisms identified. E. coli generally accounts for more than 80 percent of all species recovered in so-called uncomplicated cases, whereas Proteus, Klebsiella, Enterobacter, Pseudomonas Perugino-so, enterococci, and Staphylococcus aureus are more likely.
The Gram stain has been the most widely used of these methods and correlates about 80 to 90 percent with quantitative culture. Examination of the unstained sediment as prepared for the search for formed elements in the urine is very helpful. It is much less time consuming than the preparation of a stained slide and can be done in conjunction with the routine examination for formed elements. The criterion for positive sediment is the presence of many (preferably more than 20) obvious bacteria.
When inflammation of the bladder mucosa is intense, there may bestow erythrocytes in the urine, and gross heroamis sometimes occurs. Proteinuria is not common in urinary infections. Epidemiology and Natural History. Extensive epidemiologic studies have provided information on the frequency of bacteriuria in various populations. Bacteriuria in the newborn period has been difficult to define because of problems inherent in the collection, but the information is being obtained with the widespread use of the bladder puncture method Serratia Marcescens Infection of the urinary tract in this age group appears to be part of a generalized, life-threaten-ing gram-negative sepsis and is more common in boys than girls.
The urologic investigation is extremely valuable in this age group. The prevalence of bacteriuria among schoolgirls is 1.2 percent; it is only 0.03 percent in boys of the same' age. The incidence rate in girls is 0.3 percent per year; it is linear with time throughout the school years and is unaffected by menarche. The cumulative frequency or urinary infection in girls occur-ring at one time or another during the school years exceeds 5 percent. Urinary infection is common after marriage. Bacteriuria in pregnancy varies from 2 to 6 percent, depending upon age, parity, and socioeconomic groups. Elderly women may have frequencies of bacteriuria as high as 10 percent; this rate may rise even higher in hospitalized patients, particularly diabetics.
Serratia Marcescens Bacteriuria in the male often appears in the “prostate” years and is often initiated by instrumentation. Role of Instrumentation. Persistent bacteriuria follows single catheterizations at a frequency of 1 to 2 percent and with open indwelling catheter drainage exceeds 90 percent within three to four days. Fortunately, it is partially avoidable by (1) careful preselection of criteria for catheterization, and (2) use of aseptic closed drainage or antimicrobial bladder rinse during prolonged catheterization. The catheter should be removed as soon as it is no longer needed.