URINARY TRACT URINARY TRACT INFECTIONSINFECTIONS

Dr.T.V.Rao MDDr.T.V.Rao MD

Over view of Urinary Tract Over view of Urinary Tract InfectionsInfections

Most common infectious diseaseMost common infectious diseaseMost Numerous specimens are received in the Most Numerous specimens are received in the LaboratoryLaboratory30 to 40 % of specimens received in Microbiology 30 to 40 % of specimens received in Microbiology laboratories are Urine specimens, to Identify the laboratories are Urine specimens, to Identify the Infection.Infection.Diagnostic information is important for the clinician.Diagnostic information is important for the clinician.Appropriate clinical information gives many clues Appropriate clinical information gives many clues for better diagnostic evaluationsfor better diagnostic evaluations..Specimen collection is the primary objective in getting an Specimen collection is the primary objective in getting an ideal sample.ideal sample.

Why women are at More Risk Why women are at More Risk for Urinary Tract Infectionsfor Urinary Tract Infections

Women tend to have Women tend to have urinary tract infections urinary tract infections more often than men more often than men do because the do because the urethra is shorter in urethra is shorter in women than in men, women than in men, so bacteria have a so bacteria have a shorter distance to shorter distance to travel. travel.

Who are at Risk with UTIWho are at Risk with UTI

Urinary tract infection is much more Urinary tract infection is much more common in adults than in children, but common in adults than in children, but about 1-2% of children do get urinary tract about 1-2% of children do get urinary tract infections. Urinary tract infections in infections. Urinary tract infections in children are more likely to be serious than children are more likely to be serious than those in adults and should not be ignored. those in adults and should not be ignored.

Most Important facts to Most Important facts to establish Infectionestablish Infection

Simple microscopic examination of wet Simple microscopic examination of wet films of unconcentrated urine for detection films of unconcentrated urine for detection of Polymorphonuclear leucocytes - pus of Polymorphonuclear leucocytes - pus cells gives leading cluescells gives leading cluesSemiquantitative culture of urine to Semiquantitative culture of urine to detemine wether urine contain detemine wether urine contain potentially pathogenic bacteria in potentially pathogenic bacteria in Numbers sufficent to identify it as Numbers sufficent to identify it as causative agent causing infection.causative agent causing infection.

Common Presenting Common Presenting SymptomsSymptoms

UrgencyUrgency

Frequency of Frequency of Micturation Micturation

Discomfort and pain Discomfort and pain in abodemen or on in abodemen or on passing urinepassing urine

Organs Involved in UTIOrgans Involved in UTI

The following organs The following organs are infectedare infected

KidneyKidneyBladder Bladder UretersUreters

Donot include Urethra, Donot include Urethra, Infections of Urethra is Infections of Urethra is called as Urethritis, dealt called as Urethritis, dealt under different clinical under different clinical syndromessyndromes

Common site and MicrobesCommon site and Microbes

Patients in majority of Patients in majority of cases present with cases present with infection of Urinary infection of Urinary Bladder and called Bladder and called as Cystitis as Cystitis

Most common Most common pathogen is pathogen is Escherichia coli.Escherichia coli.

Common Pathogens Common Pathogens causing causing

UTIUTIStaphylococcus Staphylococcus saprophyticussaprophyticus

Klebsiella pneumonia – var Klebsiella pneumonia – var aerogenes or oxytocaaerogenes or oxytoca

Proteus mirabilus, other Proteus mirabilus, other coliformscoliforms

Pseudomonas aeruginosaPseudomonas aeruginosa

Streptococcus faecalisStreptococcus faecalis

Candida being a fungus can Candida being a fungus can cause infections in Diabetic cause infections in Diabetic or Immunocompromised or Immunocompromised patients.patients.

Rare Microbes causing UTIRare Microbes causing UTI

Streptococcus Streptococcus agalactiaeagalactiae

Streptococcus milleriStreptococcus milleri

Other StreptococciOther Streptococci

Anaerobic Anaerobic StreptococciStreptococci

Gardernella vaginalisGardernella vaginalis

Serious Infections associated Serious Infections associated with UTIwith UTI

Acute pyelitis Acute pyelitis

PyelonephritisPyelonephritis

May lead to Bacterimias detected by Blood May lead to Bacterimias detected by Blood cultureculture

A prominent infection with A prominent infection with Staphylococcus aureus can cause Staphylococcus aureus can cause above manifestions.above manifestions.

UTI without Routine Bacterial UTI without Routine Bacterial isolatesisolates

Some times it puzzles the clinicians, patients Some times it puzzles the clinicians, patients present with symptoms of urinary tract infection present with symptoms of urinary tract infection but bacteria donot grow on Routine culture but bacteria donot grow on Routine culture MediaMediaMay be associated withMay be associated with

Organisms that donot grow on selected Organisms that donot grow on selected mediamedia

Can be a Genito urinary tract TuberculosisCan be a Genito urinary tract Tuberculosis Gonococcal infectionsGonococcal infections Nationally exacting or anaerobic bacteriaNationally exacting or anaerobic bacteria

Non Bacterial Non Bacterial Urethritis,Cystitis Urethritis,Cystitis

and Urethral syndromesand Urethral syndromes

One should be One should be familiar withfamiliar with

Urethral or Bladder Urethral or Bladder infections with infections with

ChlamydiaChlamydia

UreaplasmaUreaplasma

TrichomonasTrichomonas

Viral infectionsViral infections

Simple tests to rule out Urinary Simple tests to rule out Urinary tract infectionstract infections

In les equipped In les equipped laboratories routine testing laboratories routine testing for detection offor detection of

NitriteNitrite BloodBlood ProteinProtein By rapid automated By rapid automated

dipsticks can give basic dipsticks can give basic informationinformation

But eliminates about ½ But eliminates about ½ of culture negative of culture negative specimens.specimens.

Collecting Urine for Collecting Urine for examinationexamination

Collect the Mid stream Collect the Mid stream specimens of Urinespecimens of Urine

Donot collect Donot collect spontaneously collected spontaneously collected urine without instructions, urine without instructions, which can lead to which can lead to contamination with contamination with commensals bacteria commensals bacteria Colonised on urethral Colonised on urethral orifice and perineumorifice and perineum

Specimen CollectionSpecimen Collection

The urine collected in a The urine collected in a wide mouthed container wide mouthed container from patientsfrom patients

A mid stream specimen is A mid stream specimen is the most ideal for the most ideal for processingprocessing

Female patients passes Female patients passes urine with a labia urine with a labia separated and mid separated and mid stream sample is stream sample is collectedcollected

Specimen collected in young and Specimen collected in young and Children Children

Non invasive methods are safe Non invasive methods are safe and idealand idealFollow the Broomhall et al Follow the Broomhall et al methodmethod

By tapping just above the pubis By tapping just above the pubis with two fingers place on with two fingers place on suprapubic region after 1 hour suprapubic region after 1 hour of feed, tapping on at the rate of feed, tapping on at the rate of 1 tap/second for aperiod of of 1 tap/second for aperiod of 1 minute, if not succesul 1 minute, if not succesul tapping is repated once agin.tapping is repated once agin.

The child spontaneously pass the The child spontaneously pass the Urine and to be collected in a Urine and to be collected in a sterile containersterile container

Transport of Urine for Culturing Transport of Urine for Culturing UrineUrine

All collected specimens of All collected specimens of urine to be transported to urine to be transported to laboratory with out delaylaboratory with out delayDelay of 1 – 2 hour deter Delay of 1 – 2 hour deter the quality of diagnostic the quality of diagnostic evaluations.evaluations.If the delay is anticipated If the delay is anticipated the specimens are at the specimens are at preserved at 4preserved at 400ccIn field conditions Boric In field conditions Boric acid can be added at a acid can be added at a concentration of 1.8 %concentration of 1.8 %

Proof of Urinary Tract InfectionProof of Urinary Tract Infection

Needs presence of potential pathogens in Needs presence of potential pathogens in the freshly voided urine or scientifically the freshly voided urine or scientifically preserved specimens in numbers greater preserved specimens in numbers greater than those likely to result from than those likely to result from contamination from urethral meatus and contamination from urethral meatus and the surrounding,the surrounding,KassKass suggested the Number to be about suggested the Number to be about 10105 5 or more ( 1,00,000 / ml of urine )or more ( 1,00,000 / ml of urine )

Diagnosis of Urinary Tract Diagnosis of Urinary Tract InfectionInfection

Step 1Step 1 Microscopy of Microscopy of

Urine for detection of Urine for detection of Pyuria.Pyuria.

Leucocytes should Leucocytes should be found in numbers be found in numbers of at least as great as of at least as great as 101044 / ml before the / ml before the pyuria is establishedpyuria is established

Wet Film examination of UrineWet Film examination of Urine

All wet films to be examined All wet films to be examined with high power ( x 40 ) with high power ( x 40 ) objective.objective.Prepare the drop of urine after Prepare the drop of urine after mixing the urine without mixing the urine without centrifugation centrifugation Transfer 0.05 ml on the middle Transfer 0.05 ml on the middle of the microscope slide and of the microscope slide and cover slip is applied.cover slip is applied.The prepared specimen show The prepared specimen show a small excess of fluid along a small excess of fluid along the edges of the cover slip.the edges of the cover slip.A approximate finding of 1 A approximate finding of 1 leukocyte / 7 high power fields leukocyte / 7 high power fields corresponds to presence of corresponds to presence of pyuria.pyuria.

Culturing of urine for Culturing of urine for Isolation of Bacterial Isolation of Bacterial

pathogenspathogensSemiquantitative Semiquantitative cultureculture

Select the MediaSelect the Media For common isolatesFor common isolates Mac Conkey’s agar Mac Conkey’s agar helps in differentation helps in differentation

of Lactose fermenting of Lactose fermenting organisms from non organisms from non lactose fermenting lactose fermenting pathogens pathogens

Selection of Loop for Selection of Loop for Semiquantitative MethodSemiquantitative Method

Culture Media for isolations- Culture Media for isolations- CLED MediumCLED Medium

It is also an excellent It is also an excellent universal culture medium universal culture medium owing to its wide spectrum owing to its wide spectrum of nutrients, lack of of nutrients, lack of inhibitors and the fact that it inhibitors and the fact that it allows a certain degree or allows a certain degree or differentiation between the differentiation between the colonies. It contains lactose colonies. It contains lactose as a reactive compound as a reactive compound which, when degraded to which, when degraded to acid, causes bromothymol acid, causes bromothymol blue to change its colour to blue to change its colour to yellow. Alkalinization yellow. Alkalinization produces a deep blue produces a deep blue colouration. The lack of colouration. The lack of electrolytes suppresses the electrolytes suppresses the swarming of Proteus swarming of Proteus

Culture Media for IsolationCulture Media for Isolation

Blood agarBlood agar

helps in isolation of helps in isolation of fastidious, extracting fastidious, extracting strainsstrains

May extended incubation May extended incubation for isolation of pathogens for isolation of pathogens for more than 48 hours for more than 48 hours with added atmosphere of with added atmosphere of 5 – 10 % co5 – 10 % co22

Specimen InoculationsSpecimen InoculationsAll cultures processedAll cultures processed by by Semiquantitative method a loop Semiquantitative method a loop of standard dimension of of standard dimension of approximately known volume is approximately known volume is inoculated into selected culture inoculated into selected culture plateplateIn general a loop of SWG – 28 In general a loop of SWG – 28 with a diameter of 3.26 mm with a diameter of 3.26 mm internal diameter which can hold internal diameter which can hold a drop of water or urine 0.004 a drop of water or urine 0.004 ml.ml.After inoculation the culture After inoculation the culture plates are incubated at 37plates are incubated at 3700c c extending to > 18 hours are read extending to > 18 hours are read The colony counts are made, as The colony counts are made, as each colony corropsdes to each colony corropsdes to number of viable bacteria per ml number of viable bacteria per ml of urineof urine

Reading the Culture PlatesReading the Culture Plates

A true infection in the absence of prior antibiotic therpay the number A true infection in the absence of prior antibiotic therpay the number of bacteria is likely to be at least 10of bacteria is likely to be at least 1055 or more. or more.Contaminated specimens present with colony counts <10Contaminated specimens present with colony counts <104, 4, however however even less than 10even less than 1033

On several occasions the colonies are diverse speciesOn several occasions the colonies are diverse speciesSeveral studies prove counts >10Several studies prove counts >104 4 to be considered as presence of to be considered as presence of Urinary tract infection with the Urinary tract infection with the supporting clinical historysupporting clinical historyOn some occasions more than one pathogen is isolated but should On some occasions more than one pathogen is isolated but should be processed for all practical purposesbe processed for all practical purposes

eg E.coli along with Streptococcus fecaliseg E.coli along with Streptococcus fecalis

On few occasions even counts 10On few occasions even counts 103 3 are are proved significantproved significant

Identification of Gram + Identification of Gram + organismsorganisms

All colonies identified All colonies identified morphologically as morphologically as

Staphylococcus to be Staphylococcus to be characterized as characterized as

Staphylococcus aureusStaphylococcus aureus Staphylococcus Staphylococcus

saprophyticussaprophyticus

Staphylococcus Staphylococcus epidermidisepidermidis

Enterococci - fecal group of Enterococci - fecal group of organismsorganisms

Identification of IsolatesIdentification of IsolatesGram + isolatesGram + isolates

The minimal tests to The minimal tests to differentiate Gram + differentiate Gram + cocci includecocci include

1 Catalase1 Catalase

2 2 Coagulase testCoagulase test

3 Bile esculin testing3 Bile esculin testing

4 Bacitricin in 4 Bacitricin in Streptococcus isolatesStreptococcus isolates

Biochemical tests in Gram - Biochemical tests in Gram - bacillibacilli

Catalase testCatalase testOxidase testOxidase testNitrite reduction testNitrite reduction testIndole testIndole testMethyl red testMethyl red testV P testV P testCitrate testCitrate testDecarboxylation testsDecarboxylation tests

Lysine, ornithine, Arginine Lysine, ornithine, Arginine teststests

Mac Conkey’s agar showing Mac Conkey’s agar showing Proteus and E.coliProteus and E.coli

Blood agar showing Coagulase Blood agar showing Coagulase negative Staphylococcusnegative Staphylococcus

Most importantMost important

Yet many theories on Significant bactenuria are Yet many theories on Significant bactenuria are contraversioal.contraversioal.The reporting of results should be maninly based on The reporting of results should be maninly based on clinical history.clinical history.Even a true infection may contain only 10Even a true infection may contain only 103 3

In such circumstances tests to be reported as probably In such circumstances tests to be reported as probably or possibly significantor possibly significantA good coordination between a Microbiologist and A good coordination between a Microbiologist and Physcian is the best solution associated with best Physcian is the best solution associated with best solutions to patients with Urinary tract infections. solutions to patients with Urinary tract infections.

Reporting of Contaminated Reporting of Contaminated specimensspecimens

Microscopy helps to detect pus cells and Microscopy helps to detect pus cells and epithelial cells, an insignificant grwoth with epithelial cells, an insignificant grwoth with few pus cells can ignored as contaminantsfew pus cells can ignored as contaminants

In females even the presence of In females even the presence of leucocytes with Squamous epthelial cells leucocytes with Squamous epthelial cells without a defined significatn growth should without a defined significatn growth should be ignored.be ignored.

Antibiotic SensitivityAntibiotic Sensitivity

Always use a pure Always use a pure grwoth of the isolates.grwoth of the isolates.

Perform testing for Perform testing for antibiotic sensitivity antibiotic sensitivity with inoculam which with inoculam which is comparable to is comparable to defined Macfarland defined Macfarland standards.standards.

Most serious Infections Most serious Infections presenting as Urinary tract presenting as Urinary tract

InfectionsInfectionsAcute pyelitisAcute pyelitisPyelonephritisPyelonephritis

May present with loin May present with loin pain, fever,pain, fever,

Apart from Urine culture Apart from Urine culture patients present with patients present with Bacteriaemia - can be Bacteriaemia - can be detected by Blood detected by Blood culture.culture.

Causative agent can be Causative agent can be Staphylococcu aureusStaphylococcu aureus

Clinical Problems Clinical Problems manifesting as Urinary manifesting as Urinary

tract Infectionstract Infections

An infection of the An infection of the Genitourinary tract Genitourinary tract where the Microbes where the Microbes donot grow on donot grow on selected media as in selected media as in Mycobacterium Mycobacterium tuberculosistuberculosis

GonococcusGonococcus Nutritionally exacting Nutritionally exacting

or anaerobic bacteriaor anaerobic bacteria

Non Specific UrethritisNon Specific Urethritis

Several conditions mimic Several conditions mimic Urinary tract infection which Urinary tract infection which are associated with organism are associated with organism other than routinely isolated in other than routinely isolated in simple and few selective simple and few selective media, they can bemedia, they can be

Can be urethral or Bladder Can be urethral or Bladder infections withinfections with

ChlamydiaChlamydia UreplasmaUreplasma Trichomonas,Trichomonas, Few virusesFew viruses

Dealing with UTIDealing with UTI

The chemotherapy of proven infection may The chemotherapy of proven infection may guided by in vitrosensitivity tests on the guided by in vitrosensitivity tests on the pathogen isolated by culture and outcome pathogen isolated by culture and outcome of therpay assessed by examination of of therpay assessed by examination of urine at the conclusion of treatment.urine at the conclusion of treatment.Follow up examination of patients with UTI Follow up examination of patients with UTI is important, if neglected can lead to is important, if neglected can lead to chronic and permanent complications.chronic and permanent complications.

Antibiotic Sensitivity TestingAntibiotic Sensitivity Testing

All the isolated All the isolated bacteria identified as bacteria identified as pathogenic to be pathogenic to be tested for Antibiotic tested for Antibiotic Sensitivity/Resistance Sensitivity/Resistance pattern by disk pattern by disk diffusion methodsdiffusion methods

Antibiotic SensitivityAntibiotic Sensitivity

Always use a pure Always use a pure grwoth of the isolate.grwoth of the isolate.

Perform testing for Perform testing for antibiotic sensitivity antibiotic sensitivity with inoculam which with inoculam which is comparable to is comparable to defined Macfarland defined Macfarland standardsstandards

Rationalsim of Antibiotic Rationalsim of Antibiotic SelectionSelection

If the patient is attending a If the patient is attending a General practice, outpatient General practice, outpatient clinic, drugs suitable by oral clinic, drugs suitable by oral administration should be administration should be selectedselectedThe discks are with defined The discks are with defined content to test the pathogens content to test the pathogens in the urinein the urine

Amoxycillin or Ampicillin 25Amoxycillin or Ampicillin 25 Cephelexin 30 µgCephelexin 30 µg Nalidixic acid 30µgNalidixic acid 30µg Ciprofloxacin 5µgCiprofloxacin 5µg Nitrofurantoin 50µgNitrofurantoin 50µg Trimethoprim 2.5Trimethoprim 2.5

ß Lactamase producing Gram ß Lactamase producing Gram negative strainsnegative strains

There is a grwoing incidence of ßlactamase producing strains in There is a grwoing incidence of ßlactamase producing strains in particular associated with Hospital acquired infectionsparticular associated with Hospital acquired infectionsThe newly defined methods to be used as per the NCCL The newly defined methods to be used as per the NCCL guidelines.guidelines.There is a growing need for testing for There is a growing need for testing for

Amikacin,Amikacin, Netilmicin,Netilmicin, TobramycinTobramycin NetilmicinNetilmicin TicarcillinTicarcillin

There is a grwoing list organisms associated There is a grwoing list organisms associated with Hospital Infections need better with Hospital Infections need better identification testing with new generation of identification testing with new generation of drugs.drugs.

Created as Teaching Module for Created as Teaching Module for Medical Students in Devloping Medical Students in Devloping

worldworld

Dr.T.V.Rao MDDr.T.V.Rao MDEmailEmail

doctortvrao@gmail.comdoctortvrao@gmail.com