Lecture 18- Microbial Diseased Of The GUT Flashcards
(26 cards)
The genitourinary tract- urinary tract
Combination of the urinary and genital tract systems = organs that work together in waste removal and reproduction
All components= subject to infection. Sterility = issue
- can be localised or systemic
Local invasion= invade the skin and mucous membranes
Ascending infection= pathogens enter the genital tract through the urethra
Microbial diseases of the genitourinary tract
Urinary tract infections= cystitis, pyelonephritis and prostatitis
Genital tract infections= cervicitis, epididymitis, genital ulcerative disease, endometriosis + pelvic inflammatory diseases + STI
Range of diseases; recurrent, STI/UTI, can be fatal; (syphillis -> dementia)
Microbes usually enter the urinary system through the urethra
Microbes usually enter the reproductive system through the vagina
Normal ‘healthy’ microbiome- urinary tract
DNA sequencing advances revealed the uro-microbiome
Upper kidney tract still considered sterile
Most abdunant bacteria in female uro-microbiome = lactobacilli, corynebacterium, streptococcus
Urinary tract infection= diagnosed using a midstream culture
Urinary tract infections
Infection of the urethra known as = urethritis
Infection of the bladder= cystitis
Infection of kidney= pyelonephritis
Prostate cancer can occur in men, known as prostatitis
Cystitis
Inflammation of the bladder caused by an infection
Symptoms; urgent need to urinate, pain/stinging when urinating
Generally self limiting- may need antibiotics
Trimethroprim= folic acid inhibitor
Nitrofuratoin= stops TCA cycle (ATP generation) + inhibits RNA/DNA and protein synthesis
More common in women then men
Shorter urethra- cross contamination easier
Almost all women will have cystitis at least once in their lifetime
Common in; pregnant women, sexually active women, post-menopausal women
Cystitis cnt
Cystitis in men;
Less common, but potentially more severe as it can indicate an underlying condition;
- underlying prostate/bladder infection
- obstruction in the urinary tract
- tumour or enlarged prostate
Acute prostatitis
Swelling of the prostate gland caused by a bacterial infection
Can cause urinary retention
Rapid antibiotic therapy required to prevent prostate damage
Symptoms;
- difficulty urinating
- pain in pelvis, genitals, lower back and buttocks
- pain when urinating and ejaculating
- high temp >38 degrees
Kidney infection- pyelonephritis
Often ascends from the bladder= untreated cystitis
Usually caused by E.coli in UTIs and E.coli and P.mirabilis in CAUTIs
Women are 6x more likely to be affected than men
May occur in young children due to abnormalities of the urinary tract
Pyelonephritis- symptoms and treatment
Symptoms;
- persistent stomach, lower back/ groin pain
- fever
- foul smelling/cloudy urine
- blood or pus
- burning pain when urinating
- change in usual urination pattern
Treatment;
- requires antibiotic therapy
- prevents kidney damage and bacteraemia/ sepsis
- vulnerable pts; preg -> admitted into hospital
- cefalexin (cephalosporin- inhibits peptidoglycan synthesis) has replaced ciprofloxacin (fluoroquinolone- DNA gyrase inhibitor)
Uropathogenic E.coli
Responsible for 80% of urinary tract infections
Women = higher rate of infection than men
E.coli= part of gastrointestinal commensal flora;
- opportunistic
- adapts quickly
Risk factors;
- sexual contact= moves bacteria closer to urethra
- improper cleaning= females wiping back to front
- menopause= lower oestrogen level
- birth control= condoms with spermicide- kills ‘good bacteria’
^ can result in kidney damage, urosepsis, , delirium
Specific adhesin- FimH
FimH= bacterial adhesin that plays an important role in the development of UTIs caused by uropathogenic E.coli
FimH is attached to the tip of some of the pili
Allows E.coli to bind to bladder epithelial cells
Stops E.coli from being flushed away when urinating
Other bacteria’s are flushed away except E.coli
Receptor= essential for pathogenesis
Catheter associated urinary tract infections
Urinary catheter drains urine from the bladder into a drainage bag
Used for;
Urinary incontinence= when a patient cannot control urination
Urinary retention= when a patient is unable to empty their bladder
Surgery= to empty the bladder before, during or after surgery
Can result in serious medical conditions;
- pyelonephritis, septicsaemia, endotoxin shock and death
Causative agent of CAUTI- proteus mirabilis
Proteus mirabilis;
Commonly isolated pathogens of all CAUTIs
Difficult to treat and often chronic long term infections, persisting even when the catheter is removed
Well adapted to its niche environment -> can block a catheter -> gaining nutrients in urine/warmth/ minimal immune response
Key virulence factors;
Swarming motility
Extensive urease production
Crystalline biofilm formation
Proteus mirabilis- treatment options
No effective approaches to control catheter blockage
Antibiotics= given to clear existing infections; cefalexin, ciprofloxacin, catheter removal
Risk of reoccurrence= high
Normal healthy microbiome- vaginal microbiome
Healthy microbiome= lactobacillus- dominated vaginal microbiome environment
- limitied oxygen available
Reduces pH of vagina ( <3.8-4.4)
Stops pathogens from colonising the area
Bacterial vaginosis
BV= microbial dysbiosis
- healthy microbes become disrupted and allows anaerobic pathogens to colonise
Caused by a disturbance of the healthy microbiome = produce lactic acid
Gardnerella vaginalis= acts as initial binding organism in BV
- binds to host cells and produces toxins
- overcomes immune defences
Bacterial vaginosis - risk factors
NOT considered an STI= women who have never had sex can develop BV
Risk factors;
- multiple sexual partners
- unprotected sex
- vaginal douching
- scented soap/deodorant/bubble bath
- Copper IUD - contraceptive (antimicrobial- microbiome disruption
Other factors; genetics/ diet/ stress
Treatment;
Antibiotics;
Metronidazole- inhibits bacterial DNA synthesis
Clindamycin= macrolide- inhibits protein synthesis
^orally/topically
Sexually transmitted infections; STIs
Infections that are passed on via sex/ sexual contact- horizontal transmission
Vertical transmission in pregnancy; syphilis/HIV can cross the placenta), gonorrhoea, chlamydia and hepatitis B= cross to baby during delivery
Bacterial= chlamydia trachomatis
Viral= hepatitis B
Fungal= trichophyton mentagrophytes; ring worm
Protozoan= trichomonas vaginalis
15-24 year olds= highest STI rates - less likely to have protected sex
Gay, bi men etc= higher proportion of STIs than straight
Chlamydia - chlamydia trachomatis
Most diagnosed bacterial STI
Caused by chlamydia trachomatis = gram - anaerobic coccobacillus - short circular rods
Intracellular- require host to survive
Symptoms;
- most people are asymptomatic; esp women
Women= vaginal discharge; white/grey/yellow with foul odour, bleeding between periods, pain passing urine and lower abdominal pain
Men= discharge from penis, burning and itching in the genital area, pain when passing urine
Treatment= doxycycline- protein synthesis inhibition
Chlamydia trachomatis; lifecycle
Cannot synthesise ATP, dependent on host cells to supply energy; obligate pathogen
2 stages to lifecycle;
1. Elementary body; non-replicating, infectious
2. Reticulate body; replicating, non-infectious
Creates and replicates within vacuoles inside host cells - sometimes even within a macrophage = evade immune response
Impact of chlamydia untr
Untreated infectious- process to serious reproductive health problems
Women = chronic pelvic pain, pelvic inflammatory disease, ectopic pregnancy and tubular factor infertility
Men- complications are rarer
Vertical transmission- pregnancy women can pass the infection on conjunctivitis/ neonatal pneumonia
Pelvic inflammatory disease; PID
Inflammation of the uterus, ovaries and fallopian tubes
Caused by bacterial infection migrating to the upper genital tract
Complications if untreated;
- Scarring; increases risks of ectopic pregnancy (fertilised egg implants in fallopian tube instead of uterus)
Infertility- blocks egg release - Sepsis; abscesses full of pus may burst and spread bacteria throughout the body
Gonorrhoea; neisseria gonorrhoea
Second most common bacterial STI in uk
Spread through unprotected vaginal, oral and anal sex with an infected partner
Causative pathogen; neiseseria gonorrhoeae
Gram - diplococcus
Attaches to oral/urinogenital mucosa by firmbriae
Females; mostly asymptomatic; vaginal discharge; green/yellow, painful urination
Males; painful urination, pus discharge and testicular swelling
Treatment; antibiotics= ceftriaxone- inhibits bacterial cell wall synthesis
N.gonorrhoeae- complications;
Can spread to other organs if left untreated
Heart= gonococcal endocarditis
Meningitis= membrane that covers the brain
Gonococcal arthritis= joint inflammation due to infection
Treatment= single antibiotic injection into buttock/thigh; ceftriaxone = stops peptidoglycan synthesis
Vertical transmission;
Ophthalmia nepnatorum; eye infection within 30 days of birth
- ocular infection- baby can become blind if untreated
Exposed to infected secretions during birth
Silver nitrate/ antibiotics added to eyes of newborn
Syphilis
Causative agent; treponema pallidum
Gram negative, highly motile and spirochete
Human pathogen only
Transmission- close sexual contact; vaginal, anal/ oral sex
Invades mucosa
Enters the host through damaged/breached skin; mouth and genitals
Primary > secondary > latent > tertiary
