7/29/2019 URINARY TRACT INFECTIONS - ESSENTIAL APPROACH
1/2
MajornumberofspecimenscomesinDiagnosticBacteriologytobe
Urine,forBacteriologicalStudiesandestablishingurinarytractinfections.
Urinary tract infection (UTI) is one of the most common disease,
occurring fromthe neonate up to geriatric age groups. Forty to 50%
of adult women have ahistory of at least one UTI. Urinary tract
infection is a major cause of Gram-negative sepsis in hospitalized
patients and after renal transplantation.Preserving Urine specimens
after collection, to be a top priority if the delay isunavoidable
in processing the specimens. Laboratories should put efforts to
doMicroscopic examination for Pus cells and epithelial cells; the
counts arereported as given per low-power field or high-power
field. Results can be alsogiven per unit volume of urine. At the
high magnification (40) the presence of
110 micro-organisms/high-power field is indicative of
bacteriuria. Thepresence of10 white blood cells/high-power field is
indicative of pyuria.On many occasions we take Kass et al criteria
in diagnosis of urinary tractinfection, Traditionally the concept
of significant bacteriuria for the diagnosis ofUTI was based on the
notion that the quantitative bacterial count alloweddistinction
between infection and contamination. The utility and consistency
ofthe criterion of105 colony-forming units per milliliter (c.f.u.
/ml) of clean-catch urine for the diagnosis of UTI has been
validated repeatedly. In children,rapid and reliable diagnosis of
UTI is mandatory and important to prevent renaldamage and other
systemic infections. In the changing concept, UTI is defined
asbacterial count 104 c.f.u. /ml urine, accompanied by
microscopical examinationof the urine to exclude vaginal
contamination (because such contamination
frequently results in false-positive culture tests). Studies by
Kunin et al. andArav-Boger et al. ASM suggested that low-count
bacteriuria might be an earlyphase of UTI. The majority of patients
with bacterial counts between 102 and104 c.f.u. /ml has
microorganisms typical for UTI (E. coli, Staphylococcussaprophytic
us, and enteric Gram-negative bacteria). As the criteria is
concernednot possible to implement by Microbiologists unless a
optimal clinicalinformation is provided. First, it is likely that
symptomatic bacteriuria of102 c.f.u./ml in symptomatic patients.
Second, a lownumber of bacteria in the urine may be the result of
increased urine output dueto high fluid in take we should avoid
collecting a specimen when the patient iswakened and already taken
sufficient fluids. Is ideal to take a specimen when the
patient awakened in the early morning. Third, low-count
bacteriuria may beproduced by slow growth of some uropathogens such
as S. saprophytic us. Wehave to use a different discrimination when
we are reporting specimens frommales where the chances of
contamination are less and significance of lowcounts are important
for interpretation of low bacterial counts withuropathogens may be
clinically meaningful. For infections with S.saprophyticusand
Candida species, the lower cutoff level of104 c.f.u./ml iscommonly
accepted. Contamination is likely if only small numbers of bacteria
orseveral bacterial species grow in urinary culture; Diptheroids,
Corynebacteriaspecies, Gardnerella, alpha-hemolytic streptococci,
and other aerobes areconsidered urethral and vaginal contaminants.
Even With years of accumulatedexperience in bacteriological
Culturing and reporting urine specimens, Reporting
continues to be difficult if taken with good spirit. As we, all
lack clinical supportin Majority of the institutions in the
Developing countries we lack precision is
