Genito-urinary Infections Flashcards
Infections
Common route
Most common bacterial infections
Main defence mechanism is flushing by urine
Usually ascends from external site up UT continuum
Catheterisation
Infections can lead to
Involvement of kidneys
Symptoms of UTI
Frequent urination
Painful urination - burning
UTI definitions
Urethritis
cystitis
dysuria
pyuria
pyelonephritis - characterised by
urethra
bladder
painful
urine that contains pus
kidney infection characterised by fever and back pain
Females are
More susceptible via fecal contamination
Host factors
Renal calculi - bacteria can stick to them
Ureteric reflux
Tumours in and adjacent to urinary tract
pregnancy, bladder stones
neuro issues - incomplete bladder emptying large volume of residual ruin
Pathogen factors
Haemolysins
Capsular antigens
Urease producing
Adhesion to uroepithelium via timbre and pillae
Diagnosis of UTI
Midstream urine Cloudy or clear Haematuria - pink urine? Culture on agar plates > 2x10^5 cells/ml Raised nitrites Pure or mixed growth Gram stain of isolated bacteria or direct staining from sample
Community bacterial causes
E.coli gram -ve rod
Proteus mirabilis - gram negative pleomorphic rod - swarming mobility
Staph saprophyticus - gram +ve coccus
Which media
if e coli suspected??
Cysteine-lactose-electrolyte-deficient (CLED) media
- rich media containing lactose and lacking electrolytes which represses swarming
Macconkey agar
Some use pH indicator containing which stains E.coli pink
Lack of electrolytes suppresses proteus swarming
Cystine promotes growth of some e.coli strains
Lactose gives lac fermentation info
Bromothymol Blue is the pH indicator in this media.
E.coli
Gram -ve
causes GI infections but UTIs commonly caused by specific strains of e.coli
have 1000 extra genes
possess potent adhesions for epithelial attachment
Pilus adresins
Type 1 pili
P-fimbriae
Binds mannose receptors, common on glycoproteins in uroepithelium
P - pyelonephritis
binds to globobiose
linked ceramide host lipids
E. coli
Proteus
Staph aureus
Large yellow colonies, opaque, centre slightly deeper yellow
Translucent blue colonies
Deep yellow - uniform in colour
Further diagnosis of UTI caused by e. coli
Lactose fermenting strain so will produce pink colonies on macconkey agar
Proteus mirabilis
swarming
found more in
Change shape - dimorphic
Ability to move over a surface
Proteus forms short curly extensions and swarms
older people and in care homes - linked to incontinence and neurological degeneration
virulence factors of PM
urease - converts urea to ammonia and co2
raise pH of urine
can cause precipitation of minerals to form kidney and bladder stones
IgA protease - reduced flushing
many pili adhesins
staphylococcus saprophyticus
gram +ve
haemagglutinin key to attachment to cells
common cause of UTIs in young women
coagulase negative (coagulase positive is ALWAYS STAPH AUREUS)
novobiocin resistant
most common in young women
Treatment of community infection
Common antibiotics - NICE
Swift antibiotic tx to prevent complications of kidney infection
3 day course in women - 7 in men
Common antibiotic - nitrofurantoin , ciprofloxacin, penicillins and trimethoprim
resistance is a growing issue esp for e.coli
Complications leading to UTI catheterisation
Common findings
Problematic??
Commonly UTIs stem from long term in dwelling catheters
Skin commensals like S.aureus (coag +ve)
Pseudomonas spp.
Klebsiella and enterococcus - PROBLEMATIC DUE TO RESISTANCE
Hospital infections - common sources
urinary tract
surgical wound
LRT
Bacteraemia
Treatment of hospital infection
May require?
Similar to community
May require IV antibiotics
Removal and changing of catheter and bag
Resistant e.coli infections now treated with plazomicin in USA
Transmission of STDs
Any form of sexual activity in which no barrier is used and exchange of fluid or contact with mucosal epithelium occurs
Recent rise in STIs is due to
Behaviour is difficult to change 420000 new cases in 2016 Chlamydia most common No vaccines Recent rise in single Over 50s - protection less likely
Syphilis
Particularly MSM
Main organisms
Gonorrhoea Chlamydia Syphilis HIV virus Genital herpes Hepatitis B
Neisseria gonorrhoeae (Gonoccus) Characteristics
Progression
Fully virulent human pathogen - not a commensal
Asymptomatic carrier state
Acute urethritis - in 95% males, only 50% females suffer discharge and dysuria
Ascend to fallopian tubes
- acute salpingitis, pelvic inflammatory disease
- endometritis
- cophoritis (ovaries)
- sterility
Ophthalmia neonatorum - infant blindness
Oral gonorrhoea - very rare but can result from oral sex with infected man
Pathogenesis of n gonorrhoeae
AEROBIC
Surface pili - bundle forming
Opa proteins
Lipo-Oligosaccharide sialylated - complement resistance - host mimicry and release sialic acid
Por proteins - nucleate actin aiding cell invasion
Possesses IgA protease - aids survival inside host cells
Antigenic variation hinder vaccination development
Release into bloodstream disseminates infection to other sites, arthritis, endocarditis
N. gonorrhoeae epidemiology
In 1980s, fear of HIV infection and increased condom usage (barrier methods) decreased infection in developed countries
Very recently, number of cases increasing again due to promiscuity, travel (including sex trade) and use of oral contraceptives over barrier methods
Co-infection of HIV and N. gonorrhoeae increases transmission of HIV by 500% (WHO)
Infection with N. gonorrhoeae also increases likelihood of contracting HIV 5x
Diagnosis and treatment of n.g
- urethral swab
- sub-culture on chocolate agar
- oxidase positive
- gram -ve diplococcus
Antibiotic prophylaxis of contacts
Historically treated with penicillin and tetracyclines
Ceftriaxone and azithromycin recommended
3rd world strains are penicillin and tetracycline resistance
Syphilis history
Major venereal disease for at least last 600 years
“French disease”
Treatment with mercury - ‘ A night in the arms of Venus leads to a lifetime on Mercury’
Syphilis - caused by
Transmission
Symptoms
Dental link
Treponema pallidum
Exclusively human
3rd most frequent STD in USA
Sexual contact via minute skin abrasions
Vertical transmissions - cross placental congenital syphilis
- primary chancre at site of infection
- enlarged inguinal nodes
- flu like illness, headache, fever, myalgia, mucocutaneous rash, spontaneous resolution
- tertiary syphilis - neurological issues, paralysis, aortic lesions, heat failure, progressive destructive disease, splenomegaly
Teeth can be malformed
Co infection
With HIV
Hinders tx
Increases infectivity and spread of HIV
Congenital syphilis
Transmitted
Transmitted cross placenta
- still birth
- congenital infection
- birth deformities, silent infection, presents as facial and dental deformities at 2 years of age
Chlamydia
Trachoma
Most common STI in the UK
Often asymptomatic in females
50% symptomatic in males
Re-infection common as immunity weak
7-14 day incubation
Disease due to direct damage to cells and immunopathology causing fibrosis and scarring
Can cause conjunctivitis - common co-occurence
Trachoma biggest cause of preventable blindness
Conjunctivitis and trachoma
Common cause of conjunctivitis Also in neonates- infection in birth Major cause of blindness worldwide with 6 million cases of blindness due to trachoma -not STI in true sense
Chlamydia in men
Asymptomatic infection ~ 50% Non specific urethritis Strong associations with: Acute epididymitis Prostatitis Male infertility
Chlamydia in women
Asymptomatic infection ~ 70 %
Mucopurulent cervicitis
Urethral infection
Pelvic inflammatory disease in up to 40% - ascending infection involving uterus, fallopian tubes, and other pelvic structures
Complications include chronic pelvic pain, ectopic pregnancy and infertility
Other diseases
proctitis - in
reactive arthritis - in - symptoms
homosexual men
mainly men - acute onset urethritis - genital swelling - knees ankles and toes - REITER’S syndrome
Neonates infected during birth –> 20% conjunctivitis +/or peumonia
Chlamydia epidemiology
Restricted cell range
Small Obligate intracellular parasite Small genome Enters through minute abrasions Specialised life cycle Avoid but not stimulate immune responses
Prefers to infect non-ciliated columnar and cuboidal epithelium - genital tract from urethra up to fallopian tubes and rectum
also respiratory and conjunctival cells
