chapter 76 - Infective Syndromes of Urinary Tract.pptx

Infective Syndromes of
Urinary Tract

Learning objectives
3
At the end of the session, the students will be able to understand:
▰ Urinary Tract Infection (UTI) and etiological Agents of UTI
▰ Identification, pathogenesis, clinical manifestations, lab diagnosis and
treatment of bacterial, viral, parasitic and fungal infections causing UTI
Essentials of Medical Microbiology

URINARY TRACT
INFECTION
4

URINARY TRACT INFECTION
5
▰ Disease caused by microbial invasion of the urinary tract that extends from
the renal cortex of the kidney to the urethral meatus.
▰ Leading cause of morbidity and healthcare expenditures in persons of all ages

Classification
6
▰ UTIs - classified into two types—lower UTI and upper UTI - depending upon
the anatomical sites involved
▰ Depending upon the source of infection: healthcare-associated (e.g. CAUTI)
and community-acquired.

Comparison between lower and upper UTIs
7
Lower UTI Upper UTI
Sites involved Urethra, and bladder Kidney and ureter
Symptoms Local manifestations:
dysuria, urgency, frequency
Local and systemic
manifestations (fever,
vomiting, abdominal pain)
Route of spread Ascending route Both ascending (common) and
descending route
Occurrence More common Less common

Epidemiology
8
▰ Second most common infection after respiratory tract infections in the
community
▰ most common HAIs (hospital acquired infections) - 35% of total HAIs
▰ Prevalence: About 10% of humans develop UTI in some part of their life

Predisposing Factors
9
▰ Gender: Higher prevalence in females
 Short urethra
 Close proximity of urethral meatus to anus
▰ Age: Incidence increases with age
▰ During first year of life prevalence same in both females and males -
incidence in males until old age

Predisposing Factors (Cont..)
10
▰ Females: incidence keeps increasing after first year of life
 5–17 years - incidence of bacteriuria - 1–3%
 Adult life - incidence is around 10–20%
 Reinfection is common in females (20–40 years of age)
▰ Pregnancy: Anatomical and hormonal changes - asymptomatic bacteriuria
common

11
▰ Structural and functional abnormality of urinary tract - obstruction to the urine
flow - urinary stasis - infection
 Structural obstruction: urethral stricture, renal and ureteric stones,
prostate enlargement, tumors, renal transplants, etc.
 Functional obstruction: neurogenic bladder due to spinal cord injury or
multiple sclerosis

12
▰ Bacterial virulence: pili - adhesion to uroepithelium
▰ Vesico-ureteric reflux: allows urine from bladder up into ureters and
sometimes into the renal pelvis
▰ Genetic factors: Genetically determined receptors help in bacterial attachment

Etiology
13
▰ Escherichia coli (uropathogenic E. coli)
 Commonest cause (70%) of all forms of UTIs - community acquired &
nosocomial UTI and upper & lower UTI
▰ Other endogenous flora - gram-negative bacilli (E.coli, Klebsiella, Proteus, etc.)
& Enterococci
▰ Hospital acquired UTIs - Enterobacteriaceae and Staphylococci, Pseudomonas

Common microorganisms causing UTIs
14
Bacterial agents Other agents
Gram-negative bacilli:
Enterobacteriaceae
 Escherichia coli: Most common (70%)
 Klebsiella pneumoniae
 Enterobacter species
 Proteus species
 Serratia species
Non-fermenters
 Pseudomonas aeruginosa
 Acinetobacter species
Fungus:
Candida albicans
Parasites:
••Schistosoma haematobium
••Trichomonas vaginalis
••Dioctophyme renale
Gram-positive bacilli:
Mycobacterium tuberculosis
Viruses:
 BK virus
 Adenovirus types– 11 and 21

Common microorganisms causing UTIs
(Cont..)
15
Bacterial agents
Gram-positive cocci:
 Enterococcus species
 Staphylococcus saprophyticus
 Staphylococcus aureus
 Staphylococcus epidermidis
 Streptococcus agalactiae

Pathogenesis
16

Ascending Route
17
▰ Most common route
▰ Enteric endogenous bacteria (E. coli, other gram-negative bacilli, enterococci)
▰ Facilitated by sexual intercourse, or instrumentation
▰ Colonization: Adhesion to urethral epithelium with help of P fimbriae,
mannose resistant fimbria in E. Coli, etc

Ascending Route (Cont..)
18
▰ Ascension: pathogen ascends through urethra upwards towards bladder to
cause cystitis
 Bacterial toxins may facilitate ascension by inhibiting peristalsis
▰ Further ascension through ureter - vesico-ureteric reflux - pyelonephritis
▰ Acute tubular injury: inflammatory cascade - tubular obstruction and damage
occurs - interstitial nephritis

Descending Route
19
▰ Bacteremia - Hematogenous seedling of pathogen (5% of UTIs)
▰ Organisms commonly associated with descending infection —
Staphylococcus aureus, Salmonella,Mycobacterium tuberculosis, Leptospira
and Candida.

Host Defense Mechanisms
20
1. Factors related to urine
2. Activation of host’s mucosal immunity by the uropathogens

Host defense mechanisms against UTIs
21
Urinary factors Mucosal immunity
Acidic urine: inhibits pathogens Uroepithelial secretion of cytokines (induced by
bacterial LPS)
High urine osmolality: inhibits pathogens Mucosal IgA–prevent attachment of pathogen to
uroepithelium
Urinary inhibition of bacterial adherence Tamm-Horsfall protein (uromodulin)—a glycoprotein
secreted by epithelial cells ofkidney,servesasanti-
adherencefactor by binding to type-I fimbriae of E. coli
Mechanical flushing by urine flow In men: (1) Zinc in prostatic secretion is bactericidal, (2)
long urethra

Clinical Manifestations
22
▰ Lower UTI: Asymptomatic bacteriuria, cystitis, urethritis, acute urethral
syndrome
▰ Upper UTI: Pyelonephritis, ureteritis, perinephric abscess, renal abscess, renal
tuberculosis
▰ Immunological sequela: Post-streptococcal glomerulonephritis (PSGN).

1. Asymptomatic Bacteriuria
23
▰ Isolation of specified quantitative count of bacteria in an appropriately
collected urine specimen, obtained from a person without symptoms of UTI
▰ Common in females and incidence increases with age

1. Asymptomatic Bacteriuria (Cont..)
24
▰ Clinically significant in - pregnant women, people undergoing prostatic
surgery or any urologic procedure where bleeding is anticipated
▰ Routine screening & treatment for asymptomatic UTI is highly recommended

1. Asymptomatic Bacteriuria (Cont..)
25
▰ Clinically not significant - in non-pregnant, pre-menopausal women, old age,
catheterized patient, or patients with spinal injury
▰ Neither screening nor treatment of asymptomatic UTI is needed

2. Cystitis (Infection of Bladder)
26
▰ Dysuria, frequency, urgency, and suprapubic tenderness
▰ Urine becomes cloudy, with bad odor, and in some cases hematuria
▰ No associated systemic manifestation

3. Acute Urethral Syndrome
27
▰ Seen in young sexually active females
▰ Classical symptoms of lower UTI as described for cystitis
▰ Bacterial count is often low (102 to 105 CFU/mL)
▰ Pyuria is present
▰ Agents: Mostly due to usual agents of UTI, few cases - caused by
gonococcus, Chlamydia, herpes simplex virus, etc

Upper UTI (Pyelonephritis)
28
▰ Inflammation of kidney parenchyma, calyces and the renal pelvis
▰ Associated with systemic manifestations - fever, flank pain, vomiting
▰ Lower tract symptoms such as frequency, urgency and dysuria

Laboratory Diagnosis - Specimen Collection
29
▰ Specimen:
1. Clean catch midstream urine
2. Suprapubic aspiration from bladder
3. Catheterized patients—urine aspirated from the catheter tube after
clamping distally and disinfecting, but never collected from urine bag
▰ Transport : Processed immediately - expected delay - refrigerated or stored by
adding boric acid

Laboratory Diagnosis - Direct Examination
30
▰ Wet mount examination - pus cells
▰ Leukocyte esterase test
▰ Nitrate reduction test (Griess test)
▰ Gram-staining

Laboratory Diagnosis - Culture
31
▰ Culture media: CLED agar (cysteine lactose electrolyte deficient agar) or
combination of MacConkey agar and blood agar.
▰ Kass concept of significant bacteriuria: Based on the fact that, though the
normal urine is sterile - may get contaminated during voiding, with normal
urethral flora.

Culture identification features of common
organisms causing UTI
32
Culture Culture smear and motility
testing
Biochemical reactions
Escherichia coli MAC or CLED: flat lactose
fermenting colonies
BA: gray moist colonies
Gram-negative
bacilli Motile
Catalase positive, oxidase negative
ICUT tests: I+ C– U– TSI (acidic
slant/acidic butt, gas+, H2S–)
Klebsiella pneumoniae MAC or CLED: mucoid lactose
fermenting colonies
BA: gray mucoid colonies
Gram-negative
bacilli Non-motile
ICUT tests: I– C+ U+ TSI (acidic
slant/acidic butt, gas+, H2S–)
Proteus species MAC or CLED: lactose non-
fermenting colonies
BA: swarming type of growth
Gram-negative pleomorphic
bacilli Motile
ICUT tests: I–/+ C+/– U+ TSI (alkaline
slant/acidic butt, gas+/–, H2S+, PPA test
positive)

Culture identification features of common
organisms causing UTI (Cont..)
33
Culture Culture smear and motility
testing
Biochemical reactions
Enterococcus MAC: magenta pink colonies
BA: translucent non-
hemolytic colonies
Gram-positivecocciinpair,
spectacle shaped
Non-motile
Catalase negative
Bile aesculin test positive
Staphylococcus aureus BA: golden yellow hemolytic
colonies
Gram-positive cocci in
clusters Non-motile
Catalase positive, coagulase positive
Staphylococcus
saprophyticus
BA: white non-hemolytic
colonies
Gram-positive cocci in
clusters Non-motile
Catalase positive, coagulase
negative, Resistant to novobiocin

Laboratory Diagnosis - Antibody Coated Bacteria
Test
34
▰ Done to differentiate upper and lower UTI.
▰ In upper UTI - route of spread is hematogenous - bacteria coated with specific
antibodies are found in urine.
▰ In lower UTI, bacteria found in urine are never coated with specific antibodies.

Treatment of Urinary tract infections
35
▰ Based on antimicrobial susceptibility testing report
▰ Preferred Drugs: Quinolones (e.g. norfloxacin), nitrofurantoin, cephalosporins,
and aminoglycosides
▰ Hopsital acquired UTIs with MDR strains: Carbapenem (e.g. meropenem),
beta lactam-beta lactam inhibitor combinations (e.g. piperacillintazobactam)
or fosfomycin

ETIOLOGICAL AGENTS
OF UTI
36

BACTERIAL UTI
37

Enterobacteriaceae Causing UTI
38
▰ Several members of the family Enterobacteriaceae can cause UTI; among
which uropathogenic E. coli is most important.

1. Uropathogenic E. coli
39
▰ Uropathogenic E. coli (UPEC) is the single most common pathogen of UTI.
▰ Accounting for 70–75% of all cases.
▰ UPEC serotypes O1, O2, O4, O6, O7 and O75 - responsible for most UTIs

1. Uropathogenic E. coli (Cont..)
40
▰ The virulence factors of UPEC include:
 Cytotoxins (CNF 1–cytotoxic necrotizing factor 1 and SAT: Secreted
autotransporter toxin)
 Hemolysins
 Fimbriae (e.g. P fimbriae)–specific for strains causing lower UTI
 Capsular K antigen–specific for strains causing upper UTI.

2. Klebsiella pneumoniae UTI
41
▰ Klebsiella pneumoniae - found as commensal in human intestines.
▰ Causes infections - urinary tract infections, meningitis (neonates), septicemia
and pyogenic infections - abscesses and wound infections

3. Enterobacter UTI
42
▰ Enterobacter species have become increasingly important nosocomial
pathogens.
▰ Opportunistic pathogens, implicated in infected wounds, UTI and pneumonia

4. Citrobacter Infections
43
▰ Mostly environmental contaminants isolated from water, soil, food and feces
of man and animals.
▰ C. freundii and C. koseri - important species causing human infections.
▰ Occasionally cause urinary tract, gallbladder and middle ear infections and
neonatal meningitis

5. Proteeae Infections
44
▰ Three genera: Proteus, Morganella and Providencia
▰ PPA positivity is the unique tribe character of Proteeae
▰ Part of commensals in human intestine.
▰ Can cause nosocomial outbreaks of UTI, wound infections, etc.

Proteus
45
▰ Proteus species show pleomorphism
▰ Named after Greek God ‘Proteus’ who was able to assume any shape

Proteus (Cont..)
46
Naming of H and O antigens:
▰ H antigen
 Ability of flagellated strains of Proteus to grow on agar as a thin film
resembling the film of breath on glass (German, ‘Hauch’ = ‘film of
breath’)

Proteus (Cont..)
47
Naming of H and O antigens (Cont..):
▰ O antigen
 Thin film is not observed when strains carrying only the somatic antigen
(nonflagellated strains) grow on media (German, ‘Ohne Hauch’ = ‘without film
of breath’)

Pathogenesis
48
▰ Proteus mirabilis & P. Vulgaris commonly encountered species
▰ Saprophytes: widely distributed in nature - decomposing animal matter,
sewage & soil
▰ Commensals: moist areas of the skin, intestine of humans and animals

Pathogenesis (Cont..)
49
▰ Infections produced: opportunistic pathogens - urinary, wound and soft tissue
infections and septicemia
 Nosocomial outbreaks
 Struvite stones in bladder: produce urease - breaks down urea to form
ammonia that damages the renal epithelium and makes the urine alkaline
- deposition of phosphate - renal calculi

Pathogenesis (Cont..)
50
▰ Proteus as the basis of Weil–Felix Reaction
 Somatic antigen of non-motile Proteus strains OX2, OX19 (from P.vulgaris)
and OXK (from P.mirabilis) cross react with antigen of Rickettsia species
 Proteus antigens - detect heterophile antibodies in sera of patients suffering
from rickettsial infections

Laboratory Diagnosis
51
▰ Pleomorphism: Proteus species are gram-negative coccobacilli occasionally
appear bacillary and infilamentous forms
▰ Odor: Putrid fishy or seminal odor in cultures
▰ Swarming: Ability to spread on the surface of solid media
▰ Swarming patterns: Continuous & Discontinuous swarming

Laboratory Diagnosis (Cont..)
52
Proteus on blood agar, showing swarming growth

53
▰ Catalase positive and oxidase negative
▰ ICUT tests: Indole test (positive for P. vulgaris and negative for P. mirabilis),
citrate test (variably positive), urease test (positive) and TSI (triple sugar iron
agar) test shows alkaline/acid, gas variably present, H2S present.

Morganella
54
▰ Only one species - M.morganii
▰ Commonly found in human and animal feces
▰ Infections: Urinary tract infection, pneumonia and wound infection – Mostly
nosocomial

Providencia
55
▰ Infections: nosocomial urinary tract, wounds and burns
▰ Five species: P. rettgeri, P. stuartii, P. alcalifaciens, P.rustigianii and P.
heimbachae

Treatment of Tribe Proteeae infections
56
▰ Often multidrug resistant & resistant to many disinfectants.
▰ Intrinsic resistance - ampicillin, first and second generation cephalosporins,
nitrofurantoin, tetracyclines, tigecycline and polymyxins (colistin and
polymyxin B).
▰ P. mirabilis is more susceptible to antibiotics than P. vulgaris.

Treatment of Tribe Proteeae infections
(Cont..)
57
▰ They produce various β-lactamases - extended spectrum β-lactamases
(ESBL) and AmpC β-lactamases - resistant to most of the β-lactam drugs.
▰ Drug of choice depends on the antimicrobial susceptibility testing.
▰ In general, aminoglycosides, fourth generation cephalosporins (cefepime),
and carbapenems are effective in treatment

Non-fermenters Causing UTI
58
▰ Non-fermenters such as Pseudomonas, Acinetobacter are important cause of
healthcare-associated UTI.
▰ They also cause skin and soft tissue infections and pneumonia

Enterococcal Infections
59
▰ Enterococci - most common gram-positive cocci to cause UTI.
▰ Initially grouped under group D Streptococcus, but later - reclassified as a
separate genus Enterococcus.
▰ Based on the molecular structure, they are now placed under a new family;
Enterococcaceae.

Virulence Factors
60
▰ Aggregation substances or pheromones - Clumping of adjacent cells to
facilitate plasmid exchange (transfers drug resistance)
▰ Extracellular surface protein (ESP) – Adhesion to bladder mucosa
▰ Common group D lipoteichoic acid antigen - Cytokine release such as tumor
necrosis factor α (TNFα)

Clinical Manifestations
61
▰ Urinary tract infections
▰ Chronic prostatitis
▰ Bacteremia and left-sided endocarditis
▰ Intra-abdominal, pelvic and soft tissue infections, surgical site infections
▰ Neonatal infections: Sepsis (mostly late-onset), bacteremia, meningitis, and
pneumonia.

62
▰ Gram-positive oval cocci arranged in pairs, arranged at an angle to each other
(spectacle-shaped appearance)
▰ Blood agar: Non-hemolytic, translucent colonies (rarely produces α or β-
hemolysis)
▰ MacConkey agar: Minute magenta pink colonies

63
A B C
A. Gram-positive oval cocci in pairs; B. translucent non-hemolytic colonies on
blood agar; C. Bile esculin hydrolysis test (left—negative, right—positive result,
black color due to esculin hydrolysis).

64
▰ Bile esculin hydrolysis test is positive
▰ Grow in presence of extreme conditions such as—6.5% NaCl, 40% bile, pH
9.6, 45oC and 10oC
▰ E. faecalis and E. faecium - differentiated by arabinose fermentation test

Treatment of Enterococcal infections
65
For less serious infections :
▰ UTI: Oral therapy with ampicillin, nitrofurantoin or fosfomycin
▰ Intra-abdominal and soft tissue infections: Ampicillin, vancomycin or linezolid
can be given.

Treatment of Enterococcal infections (Cont..)
66
For invasive infections:
▰ Endocarditis, bacteremia, and meningitis: Combination therapy with a cell
wall–active agent (e.g. penicillin or ampicillin) and an aminoglycoside (e.g.
gentamicin) is recommended
▰ Synergistic effect is due to cell wall alterations produced by cell wall–active
agents - facilitate penetration of aminoglycoside into the bacterial cell

67
For invasive infections (Cont..):
▰ This combination therapy fails if the isolate is found resistant to either
penicillin or high level aminoglycoside in vitro.
▰ In such case, alternative drugs - vancomycin, linezolid or daptomycin can be
considered.

68
▰ If resistant to vancomycin - linezolid, streptogramins (only active against E.
faecium) and daptomycin

Vancomycin Resistant Enterococci (VRE)
69
▰ In India, the VRE rate - 9.7% (overall); 2.5% for E. faecalis and 17.4% for E.
faecium (ICMR, 2019)
▰ Mechanism: Mediated by van gene - alters the target site for vancomycin
present in the cell wall - D-alanyl-D-alanine side chain of peptidoglycan layer -
altered to D-alanyl-D-serine or D-alanyl-D-lactate - less affinity for binding to
vancomycin

VRE Carriers
70
▰ Screening for VRE: High risk patients - ICUs and transplantation units
▰ Detection: Rectal swab collected and subjected to (i) Sodium azide agar with
vancomycin or (ii) PCR for detection of van gene.
▰ Management: Infection control measures - hand hygiene and isolation
precautions. Treatment (i.e. decolonization) - recommended for VRE carriers.

Other Gram-positive cocci Causing UTI
71
▰ Staphylococcus aureus
▰ Staphylococcus saprophyticus
▰ Streptococcus agalactiae

Other Bacterial Infections of Urinary Tract
72
▰ Renal Tuberculosis
▰ Post-streptococcal Glomerulonephritis (PSGN)
▰ Perinephric and Renal Abscesses

Differences between acute rheumatic fever and
poststreptococcal glomerulonephritis
73
Features Acute rheumatic fever (ARF) Post-streptococcal glomerulonephritis
(PSGN)
Prior history of infection
with
Pharyngitis strains Mainly pyoderma, or rarely pharyngitis
strains
Serotypes responsible Most of the strains of group A Streptococcus Only nephritogenic strains
Immune response Marked Moderate
Complement level Unaltered Low (due to deposition in glomeruli)
Genetic susceptibility Present Absent
Repeated attack Common Uncommon

Differences between acute rheumatic fever and
poststreptococcal glomerulonephritis (Cont..)
74
Features Acute rheumatic fever (ARF) Post-streptococcal glomerulonephritis
(PSGN)
Penicillin prophylaxis Indicated Not indicated
Course Progressive Spontaneous resolution
Prognosis Variable Good
Hypersensitivity reaction Type II Type III

VIRAL INFECTIONS OF
URINARY SYSTEM
75

BK Virus Infection
76
▰ BK virus causes nephropathy in kidney transplant recipients.
▰ Also cause hemorrhagic cystitis in hematopoietic stem cell transplant
recipients.
▰ Naming: Named after the initials of the patient in whom it was described first.
Polyomavirus, dsDNA

BK Virus Infection (Cont..)
77
Diagnosis: The diagnostic modalities include:
▰ Renal biopsy
▰ PCR
▰ Asymptomatic BK viruria (detection of BK virus DNA in urine)

BK Virus Infection (Cont..)
78
▰ Treatment: There is no specific treatment available.
▰ Cidofovir - treatment of refractory cases.

Adenovirus Cystitis
79
▰ Adenovirus serotypes 11 and 21 - acute hemorrhagic cystitis in children,
especially in boys.

PARASITIC INFECTIONS
OF URINARY SYSTEM
80

Urinary Schistosomiasis (S. haematobium)
81
▰ Schistosoma haematobium - causative agent of urinary schistosomiasis or
Bilharziasis
▰ Blood trematode (or fluke), resides in venous plexus of urinary bladder and
ureter
▰ Other two blood flukes Schistosoma mansoni and S. japonicum reside in
venous plexus of intestine and mesentery, produce intestinal disease

Life Cycle
82

Pathogenesis and Clinical Features
83
Acute Schistosomiasis
▰ The invasion of cercariae in the skin causes dermatitis at penetration site
followed by allergic pruritic papular lesion.

Pathogenesis and Clinical Features (Cont..)
84
Chronic Schistosomiasis
▰ Urogenital disease - cystitis glandularis
▰ Obstructive uropathies
▰ Bladder carcinoma - Squamous cell carcinoma

85
Urine Microscopy
▰ Diagnosis of S. haematobium
infection - detection of non-
operculated terminal spined eggs in
the urine or rarely in feces
A B

86
Histopathology:
▰ S. haematobium eggs - bladder mucosal biopsy or wet cervical biopsy
specimens (in females).
▰ Number of eggs present in crushed tissue correlates significantly with the
size of the genital lesions.

87
Antibody Detection:
▰ Useful for sero-epidemiology. Detect serum antibodies against S.
haematobium adult worm microsomal antigen (HAMA).
 HAMA-FAST-ELISA (Falcon assay screening test ELISA)
 HAMA-EITB (Enzyme-linked immunotransfer blot)
 IgE and IgG4 are elevated

88
Antigen Detection:
▰ Detection of circulating antigen - recent infection
▰ Circulating cathodic antigen (CCA) and circulating anodic antigen (CAA) -
detected in serum and urine by ELISA or dip stick assays
▰ CCA levels are much higher in urine than CAA.

Treatment of Urinary schistosomiasis
89
▰ Praziquantel - drug of choice; given 20 mg/kg/dose, two doses in single day.
▰ Metrifonate – alternatively - inhibits acetylcholine receptors on tegument
surface of adult male worm.
▰ Administered in multiple oral doses over weeks - not preferred in control
programs.

Prevention
90
▰ Proper disposal of human excreta and urine
▰ Eradication of snails by using molluscicides - metal salts (iron or aluminum
sulfate), metaldehyde, methiocarb and acetylcholine esterase inhibitors
▰ Treatment of infected persons.

Dioctophyme renale Infection
91
▰ Dioctophyme renale - “giant kidney worm” - nematode of lower animals
▰ Life cycle: Human infection - ingestion of fish infected with larva of D. renale.
▰ Larva penetrates - intestine - kidney - transform into adult worms. Adult
worms - larger in size - block the kidney and ureter.
▰ Adult worms lay eggs, that are passed in urine

Dioctophyme renale Infection (Cont..)
92
▰ Clinical features: Hematuria and renal colic,
extensive destruction of kidney parenchyma.
▰ Laboratory diagnosis: Eggs in urine - oval-
shaped, 60–80 μm size, contain an embryo
surrounded by characteristic thick
sculptured or pitted egg shell
A B

Trichomonas vaginalis Urethritis
93
▰ T. vaginalis is a sexually-transmitted parasite that primarily cause urethritis.
▰ The trophozoites may be detected in urine sediment.

FUNGAL INFECTIONS OF
URINARY SYSTEM
94

Candiduria
95
▰ Isolation of Candida species in urine - common finding - result from
contamination during collection, bladder colonization, or upper UTI (due to
hematogenous or ascending infection from bladder).

Candiduria (Cont..)
96
▰ Treatment of candiduria - considered in the following situations:
 Symptomatic cystitis or pyelonephritis, high-risk for disseminated disease
 Neutropenic or immunosuppressed patients
 Patients undergoing urologic manipulation
 If upper-pole or bladder-wall invasion or obstruction is associated
 Critically-ill patients (have higher risk for invasive candidiasis)
 Low birth weight infants

Candiduria (Cont..)
97
▰ Fluconazole (for 14 days) - drug of choice, as it reaches high levels in urine.
▰ Fluconazole resistance - oral flucytosine and/or parenteral amphotericin B can
be considered.

Questions:
98
▰ Q1. Which culture medium is preferred for processing of urine specimens:
a. TCBS agar
b. CLED agar
c. Chocolate agar
d. XLD agar

Questions:
99
▰ Q2. Which of the following is the most common etiological agent of UTI:
a. Escherichia coli
b. Klebsiella
c. Proteus
d. Enterobacter

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