Download Incidence and Prevalence

UTI FAQ's
1. Why does Urinary Tract Infections (UTI) get a lot of attention?
UTI is a serious health problem affecting millions of people each year. Infections of the
urinary tract are the second most common type of infection in the human body. UTI
accounts for about 8.3 million doctor visits each year and well over 1 million hospital
admissions in the United States annually.
2. Who is a subject to get UTI?
Although UTI occur in both men and women of all ages, clinical studies suggest that the
overall prevalence of UTI is higher in women as the result of several clinical factors
including anatomic differences, hormonal effects, and behavior patterns. One woman in
five develops a UTI during her lifetime and 20% of those have a recurrence. UTI in men
are not as common as in women but can be very serious when they do occur.
Approximately 20% of all UTI occur in men.
3. What is the UTI?
UTI is an infection of urinary system composed of the kidneys, ureters, bladder and
urethra. The microbial cause always presents in etiology of this disease. Urine is
normally sterile - that is, it does not normally contain bacteria. UTI can therefore be
occurred if bacteria inhabit the urinary tract. UTI can be restricted to the bladder
(essentially in females) with only superficial mucosal involvement, or it can involve a
solid organ (the kidneys in both genders, the prostate in males). Clinical signs and
symptoms, hazards, imaging, and treatment of various types of UTI differ. The urinary
tract can be infected from above (by bacteria entering the kidneys from the bloodstream
and traveling downward) or from below (by bacteria entering the urethra and traveling
upward).
4. How does UTI diagnosed?
The diagnosis of UTI may be made presumptively on the basis of clinical signs and
symptoms in combination with urine analysis results. Urine sample that reveals by urine
analysis both pyuria and bacteriuria is considered clinically diagnostic of UTI.
5. What method is traditionally used in laboratories for bacteriological
examination of urine samples?
The surface streak plate method using calibrated disposable loops is a standard method
for quantitative urine culturing. This method allows revealing the presence of
microorganisms responsible for the present case of UTI as growing on culture medium
isolated colonies suitable for further identification and for antimicrobial susceptibility
testing. The method means transportation of the urine sample to the bacteriological
laboratory as the procedure of bacteriological inoculation is feasible only by skilled
technician personnel.
6. What is the main disadvantage of traditional surface streak plate method?
Delay in transport and improper storage conditions may, alone or combined, limit the
quality of the final laboratory report due to the fact that urine is an excellent culture
medium and the saprophytic urethral bacteria present in it may grow rapidly at room
temperature and result in false-positive results.
7. What are the requirements and limitations of bacteriological examination of
urine?
The most common urine collection considerations include the providing of a “cleancatch” midstream urine specimen and time of inoculation. Patients should be provided
with both written and spoken “clean-catch” instructions. When a clean-catch urine
specimen is required, follow the directions given new CDC regulations, the collected
unpreserved urine should be cultured within 30 minutes after collection or refrigerated
immediately (for no more than 24 hours) to retard growth of bacteria until the test is
performed.
8. Is it enough to reveal the presence of microorganism in urine specimen for
final confirmation of UTI diagnosis?
UTI is one of rare diseases which diagnostics is based not simply on qualitative revealing
of the pathogen but on its quantitative definition. UTI cannot be identified simply by the
presence of bacteria in a voided specimen as the micturition flushes the saprophytic
urethral bacteria along with the urine, which getting in the favorable by mineral content
environment of normal urine, still keeping body temperature (makes it a great medium
for bacteria to grow in), start multiply in log phase growth, reaching of high titers during
the period of storage and transportation of sample to the lab. To distinguish this
saprophytic urethral flora from pathogenic, which in cases of clinical manifestation
reaches very high concentration of bacteria in urine, the diagnostic cut-off has been
introduced.
9. What is the diagnostic concentration of bacteria (cut-off) in urine specimen?
In the past, the presence of > 100,000 CFU/ml was regarded as a positive result while <
10,000 CFU/ml was negative. From 10,000 to 100.000 CFU/ml were considered
borderline cases, which called for repeat examination. Today, the trend is for specific
medical departments such as Urology, Nephrology and Pediatrics to report down to 1000
CFU/ml. However, this criterion is only applicable to certain population groups and
cannot currently be considered an absolute criterion. The "real" presence of any number
of bacteria in urine can represent a UTI when there are specific symptoms and pyuria.
10. What is the existing algorithm of urine analysis?
The traditional algorithm of urine analysis includes the transfer of the container with
unpreserved urine specimen to the laboratory with its subsequent manual division into
two portions, one of which is used after centrifugation for sediment microscopy on
presence of white blood cells (pyuria), whereas the second - for the bacteriological
inoculation for confirmation of the presence of bacteria in urine (bacteriuria) with
following determination of the type of bacteria and the appropriate antibiotic for
treatment. The microscopic and bacteriological examination that reveals both pyuria and
bacteriuria is considered clinically diagnostic of UTI.
11. Why is it necessary to improve diagnostics of UTI?
In search of reliability, accuracy and convenience of technique, the bacteriological
diagnostic of UTI has undergone essential changes for last decade. A variety of principal
lacks of existing algorithm concerning both general (the logistical problems related to
transportation of specimen to the lab and the “extra” unexpected charges caused by high
level of the false positive results) and professional disadvantages (unsafe urine
processing, high variability of the results because of presence of subjective factor in case
of microscopic examination of sediment, complicated and prolonged bacteriological
protocol and high level of the false positive results due to the overgrowth of saprophytic
urethral bacteria during transportation of urine influenced on) demanded the
improvement and standardization of the existing approach to laboratory examination of
urine.
12. What does a new concept of urine analysis consist of?
Novamed proprietary and unique UTI-SET System for the collection, transport,
processing and testing of urine containing of used together the Universal Urine Specimen
Container, DipStreak Urine Culture Device (UCD)and vacuum evacuated urine tube with
stabilizer changes of concept of urine examination. The sampling takes place on the
patient site! Necessity for urgent sending of containers with urine specimen to the
laboratory is excluded at all. The mentioned containers are disposed at the collection site
straight away after semi-automatic bacteriological inoculation by DipStreak UCD and
collection of urine into vacuum evacuated urine tube by the nurse. Inoculated DipStreak
UCD can be incubated overnight at the collection site before their transfer to the
laboratory, thereby negative results can be obtained next day morning and their transfer
to the laboratory is eliminated. Thus the laboratory can receive only positive specimens
(which account to less than 50% from all urine specimens) and a filled evacuated urine
tube which could be sent to the laboratory at any opportunity.
13. What is the Universal Urine Specimen Container (UUSC)?
The UUSC (Novamed Ltd., Israel) is a clear plastic urine collection cup with a capacity
of up to 120 ml of urine. The cup is closed with a screw cap containing two sampling
ports which include: (1) a luer adapter with a needle, mounted on a specifically designed
cavity on the cap. This port can be used with an evacuated urine tube for sediment
microscopy and chemical analysis and (2) a bacteriological sampling port, with a userfriendly flip-cap, to be used with a bacteriological loop or DipStreak UCD.
14. What minimal volume of urine specimen can provide proper application of
the sampling ports?
The minimal volume of urine required for efficient use of the sampling ports is marked
on the outside surface of the cup as clearly visible line and the mark “20 ml”.
15. What are the advantages of a new UUSC in comparison with other existing
already analogues?
New UUSC is designed in accordance with generally accepted standard requirements
(size, form, capacity) and maintains the technical advantages of a previous model (luer
adapter with a needle). The principal improved feature of UUSC is a unique
bacteriological sampling port with a user-friendly “flip-cap” placed on the main screw
cap, to be used with a bacteriological loop or DipStreak UCD device allowing safe and
easy access for bacteriological sampling.
16. What is the purpose of vacuum evacuated urine tube?
New UTI-SET System enables a clean transfer of 10.5 ml of sample needed for the
subsequent chemical analysis from UUSC directly into evacuated urine tube using a
difference in pressure by simple sticking of test tube on a needle of luer adapter and
significantly reduces the contamination risk for ward and laboratory personnel.
17. What is the vacuum evacuated urine tube?
The tube are sterile, leak-proof and made out of clear unbreakable disposable plastic with
a pre-defined vacuum for exact draw volumes. The urine stabilizer is intended for
stabilize urine specimens for delayed laboratory microscopic examination of urine
sediment and provides specimens protection for subsequent transport up to 5 days
without refrigeration.
18. What current problems are solved by vacuum evacuated urine tube?
The hands remain clean and the sample is protected against environmental influences!
19. What is DipStreak UCD?
DipStreak UCD (Novamed Ltd, Israel) is a new, patented urine culture device that
combines dipslide technology and a unique streaking inoculation mechanism, allowing
the semi-automated inoculation of urine specimen by unskilled personnel at the collection
site. An easy bacterial counting by only comparison with attached colony density chart,
excellent colony isolation and direct or presumptive identification of the species make it a
perfect alternative to the conventional culture method for routine laboratory use.
20. What is the technical concept of DipStreak UCD?
DipStreak UCD comprises a plastic paddle with two types of agar attached back-to-back,
housed in a closed transparent plastic tube. A ring with 6 elongated prongs attaches to the
end of the paddle, arranged so that there are 3 prongs on each side of the slide. A
transparent ring in the neck of the tube prevents the streaking prongs from moving when
the paddle is reinserted into the screw-top tube. As the paddle is pushed down into the
tube, three (3) sampling prongs streak and inoculate the surfaces of the bi-surfaced agar
slide.
21. How DipStreak UCD works?
Read Instructions for Use before beginning the test. Stand the DipStreak UCD tube on a
table or lab counter. Grasp the tube firmly with one hand. Unscrew the cap with another
hand and remove the paddle from the tube. Be careful not to touch the agar surfaces
and sterile prongs! Dip the ends of the prongs into the urine sample up to about half of
their length. Center the prongs over the opening of the DipStreak UCD tube. Press the
paddle into the tube and screw the cap.
22. What type of media combination is used in DipStreak UCD?
The DipStreak UCD have been developed taking into consideration the professional
preferences of microbiologists at work with urine samples. The useful combination of
DipStreak UCD is chromogenic agar (UriSelect 3; Bio-Rad, USA) used as the medium
for both quantitation and presumptive identification of organisms and MacConkey
selective agar used for differentiation of gram-negative microorganisms making the most
part of urine pathogens.
23. What is the advantage of chromogenic medium in comparison with the usual
C.L.E.D. agar?
The presence of organism-specific enzymatic activity is revealed by color changes in the
substrates incorporated into a peptone and tryptophan-rich chromogenic culture medium.
The use of chromogenic media increases the advantages of DipStreak UCD allowing for
direct or presumptive identification of common bacteria at the species level (E. coli, P.
mirabilis, and Enterococcus spp.) or at the group level (Klebsiella-Enterobacter-SerratiaCitrobacter and indole-positive Proteus–Morganella– Providencia) after overnight
incubation and only on the basis of colonies colour. The chromogenic media addition to
DipStreak UCD saves more time, reagents and labour on routine bacteriological ID
tests and procedures. The results obtained on the primary slide are enough for physician
to appoint the preliminary therapy and to increase the chance of patient recovery with all
logistic consequences.
24. What means a change of color of culture medium found out prior to use of
DipStreak UCD?
Any change of original color of culture medium or detection on the surface of mediums
of points or spots and furthermore, the presence of the grown colonies turns such a
DipStreak UCD unsuitable for use. Suspicious on contamination DipStreak UCD should
be disposed.
25. How to define the concentration of microorganisms in urine using
DipStreak?
Use the attached colony density chart for reporting the results. The bacterial counting
should be done by only comparison of growth pattern on slide with colony density chart.
26. How to define the mixed infection?
Preliminary identification of the bacteria can be made according to type and color of
colonies grown on chromogenic side of DipStreak UCD. If bacterial growth yields three
or more different types of colonies, this is most likely due to contamination. The test
should be repeated.
27. On what depth is it necessary to immerse the DipStreak UCD in urine?
The prongs should be dipped into the urine sample up to about half of their length when
the paddle is held in vertical position.
28. Does the result of colonies count used in DipStreak UCD display the true
concentration of microorganisms in urine?
The Colony Density Chart applied by manufacturer to count the colonies has been
calculated by summarization of results of large number of experiments, where such
parameters were considered as true quantity of the sample taken by prongs during the
sampling, true quantity of sample spent on inoculation, the size of stroked agar surfaces
and capability of media to provide the maximum recovery to grown microorganisms. The
complete coincidence between Colony Density Chart and true microbial concentration in
urine was found.
29. Whether time of dipping of the prongs into urine sample influences on the
subsequent quantitative result of analysis?
It does not matter how long the prongs having been dipped into urine sample: the
quantity of the sample spent on inoculation remains to the same.
30. Whether has value a depth of dipping the prongs into urine sample on the
subsequent quantitative result of the analysis?
As well as time of dipping, the depth of the prongs dipped into the urine sample does not
influence on the quantity of sample spent on inoculation. Do not immerse the entire
paddle!
31. What is a highest concentration of microorganisms in urine at which
DipStreak UCD is capable to provide the separated colonies?
Because of unique streaking inoculation mechanism, bacteria growth on both sides of
DipStreak UCD in three discrete lines with isolated colonies even from the samples,
which were as high as 107 CFU per ml.
32. What is the sensitivity of DipStreak UCD?
The lower level of bacteria detection of the DipStreak UCD device is between 5x102 and
1x103 CFU/ml performed following the manufacturer’s reference chart.
33. What are the advantages of DipStreak UCD in comparison with traditional
plating procedure?
Traditional culture employs a streaking dilution of the urine sample on a solid agar media
with a calibrated loop, providing accurate identification and quantification of individual
colonies. Nevertheless, one major disadvantage of this approach is that the urine must be
transported to the microbiology lab, where skilled personnel then plate it. Since urine is
an excellent medium for bacterial culture, the number of bacteria present may increase
rapidly if during transportation the sample is not refrigerated, which, of course, increases
the cost of every test performed.
Thus, a total extra-cost for traditional culturing due to (1) expensive skilled personnel
for inoculation; (2) transportation to the laboratory (3) special conditions (refrigeration)
for transported specimens (4) time consuming preparing the solid agar in the lab by
technicians.
DipStreak UCD is a leading product in comparison to the traditional culture media
with the following advantages such as (1) changing of concept of urine examination –
inoculation is done by staff at the clinic and that is why the problems of bacterial
overgrowth are solved and the pressure on the laboratory is reduced; (2) easy
protocol – simple, rapid and handy and no skilled personnel are required due to the
simple to use straightforward device; (3) convenience of transporting: inoculated
DipStreak UCD can be incubated overnight at the collection site before their transfer to
the laboratory, thereby negative results can be obtained next day morning and their
transfer to the laboratory is eliminated.; (4) safety; (5) rapidity and reliability of
determining the presence or absence of UTI as well as (6) simplicity of colony counting;
(7) saves a lot of space in the incubator due to its compact design and comfortable
incubation stand.
34. Is DipStreak UCD the same as a conventional urine dipslide?
The conventional urine dipslide is a small device with agar medium usually CLED and
MacConkey agars on each side of an immersible plastic paddle.
The conventional urine dipslide has disadvantages, which comprises its usefulness.
(1) The principal disadvantage of conventional dipslide is its inability to isolate the
separate colonies at even low concentrations of bacteria in urine, having often caused
the undifferentiated pattern of confluent growth on agar surfaces, making the detection
and isolation of urinary pathogens particularly difficult when two or more colonies are
present. It has known that all clinically significant cases of UTI are usually accompanied
with the high level of bacteriuria, so this disadvantage of conventional dipslide reduces
the economical efficiency of the method since each such case requires the additional
isolating procedures and correspondingly, the additional time, reagents and labour. (2)
Sampling of urine with conventional dipslide is cumbersome and messy: one has to dip
the whole device in urine, dry it on an absorbance paper for the excess droplets and put it
back into its vial; (3) Since large amounts of urine are absorbed by the immersed agar
surfaces, there is the possibility of false negative results due to the carry over of
inhibitory agents present in the urine (antibiotics). (4) Sampling of small volumes of
urine with the conventional dipslide is cumbersome.
35. What are the advantages of DipStreak UCD in comparison with conventional
urine dipslide?
Because of unique streaking inoculation mechanism of, bacteria growth on the
DipStreak UCD in three or two discrete lines with isolated colonies even from the
samples, which were as high as 107 CFU per ml, especially in geriatric patients. The high
ability of DipStreak UCD to separate colonies allows:
(i)
to detect rapidly the mixed cultures and to save the additional time,
reagents and labour in handling of insignificant cases of
contamination (more than two pathogens);
(ii)
to shorten the procedures of final identification and susceptibility
testing of isolated of pathogen and to save the time, reagents and
labour on intermediate isolating procedures;
(iii)
to secure easier picking for identification and antibiogram;
(iv)
low volume specimens can be used; in fact only 1cm of urine height is
necessary for safe and proper inoculation;
(v)
urine sampling directly from babies’ urine-bags is possible due to the
sampler-fork design;
(vi)
no inhibition due to the presence of antibiotics the urine;
(vii)
standardized preparation technique enables easy protocol - simple,
rapid and handy.
36. What is the reason of high profitability and cost-efficiency of DipStreak
UCD?
Despite of doubtless advantages of DipStreak UCD influencing finally on the cost of the
analysis, it is impossible to estimate correctly the cost-efficiency of each taken separately
element used in the new concept of routine urine specimen processing. It is necessary to
note, that the initial price of each separately taken element of system is high enough in
comparison with their analogues used today. Only use of all making elements as the
general system can use up to the end all advantages of elements providing the highest
profitability and cost-effectiveness of system as a whole.
37. How is reached a high ability of DipStreak UCD to separate colonies?
As a result of immersing the prongs into urine sample, each prong takes away
approximately 1-2 microlitres of it. During pushing down the slide inside the tube, each
of prongs got stuck in the neck of the tube, streaks the mentioned quantity of the sample
on a surface of agar in the form of a line with decreasing concentration. Therefore, in the
basis of a slide, whence the streaking begins, the density of growing colonies always
higher and as approaching the top of a slide where streaking comes to the end, always
there are isolated colonies. The difference in the size and the form of the working ends of
each of prongs has huge value that influences the level of their loading by urine and the
level of disposing of urine on the agar surface. Each prong under the form and the size
corresponds to one of level of bacterial contamination: high, moderate and low.
38. How properly to store inoculated DipStreak UCD until its transportation to
the laboratory?
Properly inoculated DipStreak UCD until transportation to the laboratory should be
stored at room temperature, in the dry place protected from light, for example, in branch
of a case or a drawer of a table into the personnel room. Do not place the inoculated
DipStreak UCD in a refrigerator at all!
39. How to distinguish the unused DipStreak UCD from inoculated one?
There is one external sign only which allows distinguishing the unused DipStreak UCD
from inoculated one. That is the site of the tube where the ring with the prongs aligns.
Before use, the ring with prongs settles down at the bottom of the tube, and after use the
ring with the prongs moves upwards, settling down directly under a cap.
40. What means a presence of pink drops of a liquid on internal walls of a
DipStreak UCD tube or on its internal plastic parts?
In physical meaning, DipStreak UCD represents hermetically closed system which
obligatory part is culture medium. As is known, the culture medium more than on 90 %
consists of water. During long storage of DipStreak UCD in the certain conditions
original physical balance between partial pressure of water vapor containing in
atmosphere of DipStreak UCD and culture mediums is created. This balance is broken at
any change of conditions of storage of DipStreak UCD, for example in the beginning of
its use and its transfer from the cold to the conditions of a room temperature or moreover
to incubator of 37oC. Thus, molecules of water, not having time to be absorbed by culture
mediums are condensed on internal walls of a test tube and other plastic parts of
DipStreak UCD in the form of drops of water. As one of culture mediums (MacConkey
agar) is contained of color (pink) indicator, also a condensate has a pink color. Thus, the
presence of a condensate is not a negative element and does not belittle advantages of
DipStreak UCD, but only specifies suitability of system. Besides, use of a piece of a filter
paper at the bottom DipStreak UCD be able to absorb a condensate, excludes its negative
influence on performance of DipStreak UCD.
41. Why it is not allowed to store DipStreak UCD on light?
Used in DipStreak UCD chromogenic media (UriSelect 3, Bio-Rad, USA) allows the
direct or presumptive identification of common bacteria because of presence of
organism-specific enzymatic activity which is revealed by color changes in the substrates
incorporated into medium. Such substrates demonstrate a high light sensitivity and lose
their activity under the light.
42. What are the shelf life and storage conditions of the DipStreak UCD?
DipStreak UCD is demonstrated the shelf life of 6 months under refrigeration (+2+8oC)
in dry and dark (protected from light) place. The DipStreak UCD should not be used if
there is any sign of growth or shrinking of the culture medium (surrounding gap > 1 mm).
DipStreak UCD remains usable when the agars are smooth and attached to the slide. A
small amount of water (condensate) may collect and in a consequence be absorbed in a
piece of filter paper placed in the bottom of the tube.
43. What are the main advantages of new UTI-SET System Processing Protocol?
The new UTI-SET System finally provides with the reducing of overall expenses, safety
and simplicity of Processing Protocol.
The New UTI-SET System Processing Protocol is more economical in mass using
because of reducing of total expenses (time, reagents and labour) of urine examination.
The sampling procedure by all components of UTI-SET System is semiautomatic and
could easily and correctly carry out by unskilled personnel or patient himself (!) and
safely conveyed to the laboratory.
All components of UTI-SET System are the closed systems limiting direct contact of
personnel with sample during handling and inoculation procedure and prevent the
spreading of nosocomial bacteria in the hospital or community area. Whether it be in a
laboratory, on the ward or in a doctors surgery, the Novamed's UTI-SET System is a
hygienic multi-talent for use in various fields.