Microbiology

• What are the main transmission routes for infections?

  • Direct contact
  • Droplet/respiratory infection
  • Faecal-oral route
  • Blood borne
  • Sexually transmitted
  • Vector-borne
  • Zoonosis
  • Congenital infection
• Which organism is associated with droplet/respiratory infection?

  Mycobacterium tuberculosis
• What are the possible sites for microbial infections?

  • Upper respiratory tract
  • Lower respiratory tract
  • Genitourinary tract
  • Gastrointestinal tract
  • Skin and soft tissue
  • Central nervous system
  • In utero (congenital infection)
• What are the types of infection?

  • Acute
  • Chronic
  • Recurrent
• What characterizes an acute infection?

  Rapid onset of symptoms
• What are the symptoms of a common cold?

  Rhinitis, sneezing, sore throat, cough, headache
• How is a common cold diagnosed in the laboratory?

  Multiplex respiratory PCR of respiratory sample
• What are the symptoms of acute liver failure?

  Jaundice, abdominal pain, nausea, vomiting
• What laboratory diagnosis is used for acute liver failure?

  Blood sciences markers (esp LFTs)
• What are the symptoms of chronic Chlamydia infection?

  Usually none until infertility, ectopic pregnancy
• How is chronic Chlamydia infection diagnosed?

  PCR of genital swabs, urine
• What are the three distinct types of recurrent infections?

  1. Re-infection
  2. Reactivation
  3. Recrudescence
• What characterizes re-infection?

  Repeated exposure to the pathogen
• What are the symptoms of urinary tract infections?

  Cystitis, cloudy urine, pyrexia, confusion
• How is a urinary tract infection diagnosed?

  Cell count of urine sample, culture & sensitivity
• What characterizes reactivation infections?

  Activation of dormant pathogen
• What are the symptoms of oral herpes?

  Tingling, fluid-filled lesions
• How is oral herpes diagnosed?

  Clinical, PCR to detect HSV genome
• What characterizes recrudescence infections?

  Pathogen persists undetected and reappears
• What are the symptoms of Plasmodium falciparum infection?

  Pyrexia, rigours, headache, diarrhoea
• How is Plasmodium falciparum diagnosed?

  Blood slides; monitor parasitaemia
• What are common clinical symptoms of infections?

  • Pyrexia
  • Rigours
  • Nausea
  • Vomiting
  • Lethargy
  • Diarrhoea
• What is the importance of laboratory diagnosis in clinical infections?

  • Identifies causative organisms
  • Confirms clinical diagnosis
  • Determines appropriate treatment
• What are the laboratory diagnosis methods for upper respiratory tract infections?

  • Throat swab collection
  • Bacterial culture
  • Gram stain
  • Biochemical tests
  • Molecular biology for strain variation
• What is the laboratory culture medium for throat swabs?

  Blood agar
• What is the purpose of follow-up identification tests in laboratory diagnosis?

  To determine species of isolated organisms
• What is the laboratory diagnosis method for viruses in URTIs?

  Polymerase chain reaction
• What are the laboratory diagnosis methods for lower respiratory tract infections?

  • Culture on chocolate blood agar
  • Microscopy for direct detection
  • Multiplex PCR
• What are the common organisms causing lower respiratory tract infections?

  Streptococcus spp., Haemophilus influenzae
• What are the clinical symptoms of lower respiratory tract infections?

  Pyrexia, productive cough, difficulty breathing
• How is respiratory syncytial virus diagnosed?

  Fluorescent-labelled anti-RSV antibodies
• What is the appearance of H. influenzae on chocolate agar?

  Greyish, small colonies
• What are the laboratory diagnosis methods for clinical infections?

  • Urinary tract infections
  • Gastrointestinal infections
  • Sexually transmitted infections
• What are the methods of control for infectious diseases?

  • Prevent contact between cases and hosts
  • Antimicrobial therapy
  • Vaccination
  • Limit thriving conditions
• Why are some infections considered mild and self-limiting?

  They pose minimal risk to health
• What is essential for effective control programs of infectious diseases?

  Understanding of biology and epidemiology
• What is the definition of an emerging infection?

  Increased incidence or geographical spread
• What is the genome type of coronaviruses?

  Positive sense single stranded RNA
• What is the full name of SARS-CoV-2?

  Severe acute respiratory syndrome coronavirus - 2
• What is the classification of SARS-CoV-2?

  • Realm: Ribovira
  • Order: Nidovirales
  • Suborder: Cornidovirineae
  • Family: Coronaviridae
  • Subfamily: Orthocoronavirinae
  • Genus: Betacoronavirus
  • Species: SARS, MERS-CoV, SARS-CoV-2