Bacterial infections 1

• pathogenesis


  ability of microorganism to cause disease
• Virulence


  intensity of disease/degree of harm caused
• Name the types of infection

  acute, chronic, latent, HAI, opportunistic, primary, secondary, systemic, bacteriemia
• Acute infection


  comes on rapidly, with mild or severe short-lived effects (cold, appendicitis)
• Chronic infection


  an infection that generally develops slowly and lasts for months or years (TB)
• Latent infection


  appears a long time after initial infection (shingles, TB)
• HAI


  results from direct treatment in healthcare setting (MRSA, E.coli)
• Opportunistic infection


  caused by a pathogen that does not normally produce an illness in healthy humans (C.difficile)
• Primary infection


  initial infection in patient (surgical site, UTI)
• Secondary infection


  infection after primary infection (sepsis)
• systemic infection


  infection spreads to several sites and tissue fluids usually in the bloodstream
• Bacteraemia infection


  bacteria present in blood - small amount not a problem
• Upper respiratory tract infection sites

  nose/throat, ear and eye
• Nose/throat infections

  pharyngitis and tonsillitis

  group A strep (GAS) = mild/treatable 'strep throat'

  spread by droplets
• pharyngitis and tonsillitis symptoms

  inflamed tonsils, hard to swallow, fever, headache

  
• pharyngitis and tonsillitis complications

  quinsy, otitis media, schusctis, bacteraemia
• pharyngitis and tonsillitis rare symptoms

  1. scarlet fever = strep throat symptoms and body rash

  2. AI effect trigger = rheumatic fever

  3. invasive infection (iGAS) = GAS infection breaches barriers to become life-threatening
• Ear infections

  otitis media

  strep pneumoniae, haemophilius influenzae
• Otitis media


  acute symptoms = pain, hearing loss, dizziness, fever

  chronic = tissues around Eustachian tube swell

  
• Eye infections

  Conjunctivitis (conjunctiva = loose connective tissue over eyeball surface)
• Conjunctivitis


  Symptoms = redness, more tears, thick yellow discharge, itchy, blurred vision

  treatment = topical chloramphenicol

  
• Conjunctivitis STD association

  1. gonorrhoeae = severe in newborns - perforation of cornea

  2. chlamydia = repeated infection causes Trachoma - roughening of inner eyelid and is spread by contact (towels, flies)
• Lower respiratory tract infection sites

  trachea/bronchi
• acute bronchitis


  mycoplasma pneumoniae

  chronic = due to smoking/irritants - associated with COPD

  symptoms = persistent cough, excessive mucous secretion

  primary can lead to secondary = severe acute bronchitis (productive cough)

  
• Pneumonia


  inflammation of alveoli (strep pneum, haem inf, S.aur, Kleb pneu)

  symptoms = fever, cough, pain breathing

  
• TB


  Mycobacterium tuberculosis - can be latent

  symptoms = persistent productive cough (>3 weeks and blood), chest pain

  
• UTIs ascending vs descending

  ascending = bacterium enter urethra and travel upwards (usually G-ve such as E.coli)

  descending = UT is infected from blood e.g. staph (rarer and more serious)
• UTI factors


  length of urethra

  catheters

  disruption of normal urine flow (pregnancy)

  older age (incomplete bladder emptying)

  diabetes
• UTI symptoms


  lower = hard to pee, increased urge, cloudy urine, pain, unwell

  upper = less symptoms, pain in side/lower back, fever, nausea, blood in urine
• STIs


  bacterial = chlamydia, gonorrhoeae

  viral = HIV, HPV, Herpes

  fungal = Candida albicans
• Chlamydia


  symptoms = discharge, pelvic pain, infertility

  complications = kidney disease, premature births, ectopic pregnancies