urinary tract infections clinical based learning

Urinary Tract Infection Clinical Based Learning: 

Urinary Tract Infection Clinical Based Learning Dr.T.V.Rao MD Dr.T.V.Rao MD 1

Clinical Presentation : 

Clinical Presentation A 30 years female patient presented with frequencency and urgency in Urination with raise of body temperature since 3 days. She also presented with lower abdominal pain since 4 days What can be your Provisional Clinical Diagnosis ? Dr.T.V.Rao MD 2

Signs and Symptoms of Urinary Tract Infection: 

Signs and Symptoms of Urinary Tract Infection Elevated temperature —(vital signs) Elderly require > time to present with fever, may not have any increase in temperature → may even be hypothermic Elderly at ↑’d risk for masked or absent fever response due to antipyretics, corticosteroids, chemo Rx, alcoholism, hypothyroidism, malnutrition and renal insufficiency Studies indicate fever is a marker for serious infection & most important clinical indicator for antibiotic treatment Other studies, fevers can resolve without treatment; antibiotics did not improve outcomes in elderly Not always due to UTI—consider differential diagnoses: pulmonary or skin infections Lack of fever may delay diagnosis Dr.T.V.Rao MD 3

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The provisional diagnosis can be a Urinary tract infection (UTI ) Define Urinary Tract Infection ? What are the possible etiological agents ? Dr.T.V.Rao MD 4

Organs Involved in UTI: 

Organs Involved in UTI The following organs are infected Kidney Bladder Ureters Do not include Urethra, Infections of Urethra is called as Urethritis, dealt under different clinical syndromes Dr.T.V.Rao MD 5

What is a Urinary Tract Infection: 

What is a Urinary Tract Infection A n infection of one or more structures in the urinary system. Most UTIs are caused by gram-negative bacteria, most commonly Escherichia coli or species of Klebsiella, Proteus, Pseudomonas, or Enterobacter, although other strains, such as Staphylococcus and Serratia, are emerging Dr.T.V.Rao MD 6

Notes on pathogens: 

Notes on pathogens * Escherichia coli : the commonest urinary pathogen causing 60-90 % of urinary infections * Pseudomonas, Proteus, Klebsiella and S. aureus are associated with hospital acquired infections because their resistance to antibiotics favor their selection in hospital patients (catheterization, gynaecological surgery) * Proteus infections are associated with renal stones Proteus produce a potent urease which act on ammonia, rendering the urine alkaline * S. saprohyticus infections are found in sexually active young women Dr.T.V.Rao MD 7

Rare Microbes causing UTI: 

Rare Microbes causing UTI Streptococcus agalactiae Streptococcus milleri Other Streptococci Anaerobic Streptococci Gardernella vaginal is Dr.T.V.Rao MD 8

Notes on pathogens: 

Notes on pathogens * Candida urinary infection is usually found in diabetic patients and immunosuppression * Infection of the anterior urinary tract (urethritis) is mainly caused by N. gonorrhea , staphylococci, streptococci and chlamydia * M. tuberculosis is carried in blood to kidney from another site of infection (e.g. respiratory T.B.) Dr.T.V.Rao MD 9

What is the Basis of Diagnosis of Urinary Tract Infection ?: 

What is the Basis of Diagnosis of Urinary Tract Infection ? Dr.T.V.Rao MD 10

Diagnostic Criteria: 

Diagnostic Criteria Pyuria A host response to infecting bacteria causing an increase of white blood cells or pus in the urine Associated with presence of both symptomatic and asymptomatic UTI’s in elderly Level of pyuria is ↑ when infected with a gram negative organism Most research finds this is so common that it has questionable value in UTI detection and as an indicator for Rx in the absence of clinical symptoms Dr.T.V.Rao MD 11

Collecting the Urine: 

Collecting the Urine There are several different methods for collection of a urine sample. The most common is the midstream clean-catch technique . Hands should be washed before beginning. For females, the external genitalia (sex organs) are washed two or three times with a cleansing agent and rinsed with water. In males, the external head of the penis is similarly cleansed and rinsed. The patient is then instructed to begin to urinate, and the urine is collected midstream into a sterile container. Dr.T.V.Rao MD 12

Collected in wide mouthed container: 

Collected in wide mouthed container The urine collected in a wide mouthed container from patients A mid stream specimen is the most ideal for processing Female patients passes urine with a labia separated and mid stream sample is collected Dr.T.V.Rao MD 13

Early inoculation a Priority: 

Early inoculation a Priority Urine collected in sterile specimen container must be processed within 2 hours, or refrigerated and processed within 24 hours Urine collected in sterile specimen container with borate preservative should be processed within 24 hours (no refrigeration required) Dr.T.V.Rao MD 14

Collection of Urine Catheterized Patients: 

Collection of Urine Catheterized Patients Another method is the catheterized urine specimen in which a lubricated catheter (thin rubber tube) is inserted through the urethra (tube-like structure in which urine is expelled from the bladder) into the bladder. This avoids contamination from the urethra or external genitalia. Dr.T.V.Rao MD 15

Suprapubic aspiration: 

Suprapubic aspiration On rare occasions, the health care provider may collect a urine sample by inserting a needle directly into the bladder (suprapubic tap) and draining the urine; this method is used only when a sample is needed quickly and technically competent staff are available Dr.T.V.Rao MD 16

Specimen collected in Infants and Children: 

Specimen collected in Infants and Children Non invasive methods are safe and ideal Follow the Broomhall et al method By tapping just above the pubis with two fingers place on suprapubic region after 1 hour of feed, tapping on at the rate of 1 tap/second for period of 1 minute, if not successful tapping is repated once again. The child spontaneously pass the Urine and to be collected in a sterile container Dr.T.V.Rao MD 17

Transport of Urine for Culturing Urine: 

Transport of Urine for Culturing Urine All collected specimens of urine to be transported to laboratory with out delay Delay of 1 – 2 hour deter the quality of diagnostic evaluations. If the delay is anticipated the specimens are at preserved at 4 0 c In field conditions Boric acid can be added at a concentration of 1.8 % Dr.T.V.Rao MD 18

Wet Film examination of Urine: 

Wet Film examination of Urine All wet films to be examined with high power ( x 40 ) objective. Prepare the drop of urine after mixing the urine without centrifugation Transfer 0.05 ml on the middle of the microscope slide and cover slip is applied. The prepared specimen show a small excess of fluid along the edges of the cover slip. A approximate finding of 1 leukocyte / 7 high power fields corresponds to presence of pyuria . Dr.T.V.Rao MD 19

Selection of Loop for Semi quantitative Method: 

Selection of Loop for Semi quantitative Method Dr.T.V.Rao MD 20

Culturing of urine for Isolation of Bacterial pathogens: 

Culturing of urine for Isolation of Bacterial pathogens Semi quantitative culture Select the Media For common isolates MacConkey agar helps in differentiation of Lactose fermenting organisms from non lactose fermenting pathogens Dr.T.V.Rao MD 21

Culture Media for Isolation : 

Culture Media for Isolation Blood agar helps in isolation of fastidious, extracting strains May extended incubation for isolation of pathogens for more than 48 hours with added atmosphere of 5 – 10 % co 2 Dr.T.V.Rao MD 22

What you understand by Significant bacteriuria ?: 

What you understand by Significant bacteriuria ? Significant bacteriuria in an asymptomatic patient is 100,000 or more colonies per milliliter of urine from a midstream, clean-catch specimen; Dr.T.V.Rao MD 23

Mac Conkey’s agar showing Proteus and E.Coli: 

Mac Conkey’s agar showing Proteus and E.Coli Dr.T.V.Rao MD 24

How you interpret counts ?: 

How you interpret counts ? Up to 10 4 /ml considered normal i.e. Insignificant 10 5 /ml and above considered to be Significant Concept valid only for voided specimen of urine Exceptions - slow growing organisms, patient on antibiotic therapy, diuretic therapy Dr.T.V.Rao MD 25

Most important point in Interpretation: 

Most important point in Interpretation Yet many theories on Significant bactenuria are controversial. The reporting of results should be mainly based on clinical history. Even a true infection may contain only 10 3 In such circumstances tests to be reported as probably or possibly significant A good coordination between a Microbiologist and Physician is the best solution to patients with Urinary tract infections. Dr.T.V.Rao MD 26

What are different Biochemical tests you perform different isolates ? : 

What are different Biochemical tests you perform different isolates ? Catalase test Oxidase test Nitrite reduction test Indole test Methyl red test V P test Citrate test Decarboxylation tests Lysine, ornithine, Arginine tests Dr.T.V.Rao MD 27

Antibiotic Sensitivity: 

Antibiotic Sensitivity Always use a pure growth of the isolates. Perform testing for antibiotic sensitivity with inoculum which is comparable to defined McFarland sta ndards. Dr.T.V.Rao MD 28

How you perform Antibiotic Sensitivity Testing ?: 

How you perform Antibiotic Sensitivity Testing ? All the isolated bacteria identified as pathogenic to be tested for Antibiotic Sensitivity/Resistance pattern by disk diffusion methods Dr.T.V.Rao MD 29

Issues on Urinary Tract infection: 

Issues on Urinary Tract infection Dr.T.V.Rao MD 30

Causative Pathogens and other implication: 

Causative Pathogens and other implication UTI in Women Escherichia coli —gram (-) etiologic agent in ~ 80% of all UTI’s Research indicates primary source of microbial invasion is retrograde colonization by intestinal pathogens Other factors influencing colonization: vaginal pH, urethral length, capacity of bacteria to adhere to urothelium Osborne, 2004 = Dr.T.V.Rao MD 31

Urinary Tract Infection Why it is Important: 

Urinary Tract Infection Why it is Important Urinary tract infection—most common source of bacteremia, a dangerous systemic infection in long-term care facilities Bacteremia—40 times more likely to occur in catheterized than non-catheterized residents Bacteremia leads to significant morbidity and mortality in the vulnerable elderly Dr.T.V.Rao MD 32

Clinical Problems manifesting as Urinary tract Infections: 

Clinical Problems manifesting as Urinary tract Infections An infection of the Genitourinary tract where the Microbes do not grow on selected media as in Mycobacterium tuberculosis Gonococcus Nutritionally exacting or anaerobic bacteria Dr.T.V.Rao MD 33

What is Polymicromial bacteriuria : 

What is Polymicromial bacteriuria Contamination most frequent cause of multiple microorganisms 25-33% in LTCF’s may be polymicrobic due to fistulas, urinary retention, infected stones, or catheters Dr.T.V.Rao MD 34

Non Specific Urethritis: 

Non Specific Urethritis Several conditions mimic Urinary tract infection which are associated with organism other than routinely isolated in simple and few selective media, they can be Can be urethral or Bladder infections with Chlamydia Ureplasma Trichomonas, Few viruses Dr.T.V.Rao MD 35

Serious Infections associated with UTI: 

Serious Infections associated with UTI Acute pyelitis Pyelonephritis May lead to Bacteremia's detected by Blood culture A prominent infection with Staphylococcus aureus can cause above manifestations. Be prompt to diagnose Urinary Tract Infections Dr.T.V.Rao MD 36

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Created by Dr.T.V.Rao MD for Microbiology Students in Developing World Email doctortvrao@gmail.com Dr.T.V.Rao MD 37