Infections

• Tuberculosis


  • Mycobacterium tuberculosis
  • Usually found in wet environment
  • Aerobic
  • Hydrophobic
  • Unique cell wall- lipid rich
  • Droplet inhalation
• Tuberculosis symptoms and diagnosis


  • Pulmonary disease
  • 3 sputum samples + presence of AFB
  • TB meningitis
  • Diagnosis based on signs, symptoms, history, imaging
• Tuberculosis treatment


  1. Refer to specialist

  2. Initial 2 MONTHS: Rifampicin, Isoniazid, Pyrazinamide, Ethambutol

  3. Continuous 4 MONTHS: Rifampicin, Isoniazid

  4. 2nd line drugs: Capreomycin, Cycloserine, Fluoroquinolones
• Rifampicin


  • Inhibits DNA-dependent RNA polymerase- inhibits transcription
  • Broad spectrum including gram + and -
• Isoniazid

  • Inhibits synthesis of mycolic acids
  • Pro-drug
• Pyrazinamide


  • Multiple targets
  • Intracellular acidification
  • Disrupts plasma membrane
• Ethambutol


  • Inhibits cell wall synthesis
  • Resistance rapidly when used alone
  • AE= dose related optic neuropathy (red/green colour blindness), mental disturbances
• Streptomycin


  • Aminoglycoside
  • Bactericidal
  • Induce misreading of mRNA
  • Gram – but some gram +
  • Dose related AEs
• Capreomycin

  • Peptide antibiotic
  • I.M.
  • Nephrotoxic and ototoxic
• Cycloserine


  • Broad spectrum
  • Inhibits synthesis of peptidoglycan (blocks addition of amino acids)
  • Resistant TB
• Fluoroquinolones


  • Ciprofloxacin, levofloxacin
  • Inhibit DNA topoisomerase II and IV
• DO NOT have to pay if on a PGD (but do if on FP10)
• BCG vaccination

  • Live attenuated vaccine
  • 0-12 months child & those at high risk
• Tuberculosis resistance

  • MDR-TB
  • RR-TB (rifampicin-resistant)
  • XDR-TB (extensively drug resistant TB)
• Scarlet fever


  • Streptococcus pyogenes (impetigo)
  • Children 2-8 years
  • Highly infectious- spread by droplets
  • 2-5 days to develop symptoms
• Scarlet fever management


  1. Exclude from school/work until at least 24 hours after the start of antiobiotic treatment

  2. Phenoxymethylpenicillin QDS 10 days or amoxicillin

  3. Fluids

  4. Soft diet

  5. Analgesics
• HIV

  • Lentivirus- destroys CD4 T-cells
  • HIV-1: 4 groups, M most common with 9 subtypes, C most common
  • CRFs= when 2 subtypes meet in the same host cell and share genetic code
  • HIV-2: Less transmissible in humans
• HIV testing


  • 3rd generation: ELISA antibody test
  • 4th generation: ELISA antibody and p24 antigen
  • Self-testing: Oraquick
  • PCR
• Primary HIV symptoms


  Rash, fever, diarrhoea, lymphadenopathy
• Chronic HIV symptoms

  Weight loss, fever, night sweats, large lymph glands
• AIDS

  • Kaposis sarcoma, TB, cryptococcal meningitis
  • CD4 count below 200cells/µL
• HIV treatment

  1. Before- screen for HIV resistance, hep B&C, CVD risk, diabetes

  2. Tenofovir/ emtricitabine with dolutegravir

  3. Abacavir/lavivudir/ dolutegravir

  4. Tenofovir/ emtricitabine/ bictegravir

  5. Doutegravir/ lamivudine
• Malaria

  Plasmodium falciparum: Resistant to chloroquine and mefloquine
• Malaria symptoms


  Flu-like symptoms (cytokines), fever above 41, history
• Malaria transmission

  1. Female bites, sporozoites enter the blood, then to the liver where they replicate then 5-16 days after they burst

  2. Incubation period 10-21 days
• Malaria treatment


  1. Quinine, proguanil with atovaquone or artemether with lumefantrine followed by a course of doxycycline/clindamycin

  2. If parasite sensitive= pyrimethamine with sulfadoxine

  3. Chloroquine for benign malaria (Plasmodium vivax)
• Quinine


  Derived from cinchona bark
• Proguanil


  Active metabolite= cycloguanil= inhibits folate production by inhibiting dihydrofolate reductase in both pre-erythrocytic and erythrocytic parasites
• Malaria awareness

  • A= awareness
  • B= bite
  • C= chemoprophylaxis
  • D= diagnosis
• Chemoprophylaxis


  • Start 2-10 days before travel
  • Casual- attacks malaria at schizont stage in the liver
  • Suppressive- prevents parasite using Hb as an energy source
  • E.g. Atovaquone + proguanil (Maloff)
• HIV: gp120 binds to CD24 to induce confirmational change in gp120, then gp41 interacts with host cell to then enter, reverse transcriptase then allows for the viral DNA to move in the cell, translocation of the viral mRNA occurs and then viral proteins are made and release into blood
• enfuvirtide ONLY HIV drug licensed for treatment resistant HIV
• fusion/entry inhibitor: enfuvirtide
• NRTI: tenofovir
• NNTRI: doravivine
• NNRTI and NRTI work to inhibit HIV reverse transcriptase
• enfuvirtide works to inhibit viral replication by inhibiting entry into host cell
• integrase inhibitors work by blocking the viral integrase enzyme
• protease inhibitors work by blocking the enzyme that catalyses the breakdown of proteins
• integrase inhibitors: raltegravir