Normal Flora

  • Microorganisms living on living organisms/inanimate objects without causing disease.
  • Approximately 100 trillion bacteria in human intestines; found in skin, respiratory, urinary, and digestive tracts.
  • Functions include:
    • Digestion
    • Bile salt conversion
    • Vitamin K production
    • Immune system stimulation
    • Intestinal transit aid
    • Susceptibility to pathogens.

Flora Distribution

  • Skin flora: Gram-positive organisms (e.g., Staphylococcus epidermidis)
  • Oral/respiratory flora: Streptococcal anaerobes, Neisseria
  • Gastrointestinal flora: Helicobacter pylori, anaerobes (transient due to acidity)
  • Urogenital flora: Changes with hormones (e.g., Candida spp.)
  • Ear flora: Aerobic species, viruses, fungi.

Staphylococcus aureus

  • Pathogenicity: Gram-positive cocci, causes various infections (boils, pneumonia, UTI, food poisoning).
  • Transmission: Direct contact, contaminated objects, aerosol droplets, contaminated food.
  • Diagnosis: Laboratory culture.
  • Treatment: Methicillin for sensitive strains; Vancomycin for MRSA.

Escherichia coli

  • Pathogenicity: Common intestinal bacteria; certain strains cause UTI, sepsis, gastroenteritis.
  • Transmission: Contaminated food, water, person-to-person.
  • Diagnosis: Lab isolation; characterized by Gram-negative, indole-positive, motile rods.
  • Treatment: Antimicrobials like sulphonamides and amoxicillin may be used.

Neisseria gonorrhoeae

  • Pathogenicity: Gram-negative diplococcus, causes gonorrhea.
  • Transmission: Sexual contact, asymptomatic in women.
  • Diagnosis: Clinical symptoms and lab identification.
  • Treatment: Ceftriaxone with Azithromycin/Doxycycline for uncomplicated cases.

Candida albicans

  • Pathogenicity: Opportunistic yeast causing candidiasis.
  • Transmission: Mother to infant during birth, not typically contagious.
  • Diagnosis: Lab isolation from specimens; typical symptoms include vaginal discomfort.
  • Treatment: Antifungals such as fluconazole for various candidiasis forms.

Clostridium tetani

  • Pathogenicity: Spores cause tetanus via neurotoxin release.
  • Transmission: Contaminated wounds.
  • Diagnosis: Clinical symptoms, muscle spasms.
  • Treatment: Supportive care, cleaning wounds, antibiotics.

Vibrio cholera

  • Pathogenicity: Causes cholera, characterized by watery diarrhea.
  • Transmission: Fecal-oral route, contaminated food/water.
  • Diagnosis: Clinical signs, laboratory stool sampling.
  • Treatment: Rehydration, IV fluids, antibiotics like doxycycline.

Hepatitis B Virus (HBV)

  • Pathogenicity: Causes serious viral hepatitis, potential for liver cancer.
  • Transmission: Blood, sexual contact, from mother to infant.
  • Diagnosis: HBsAg detection, additional serological tests for chronic infection.
  • Treatment: Medication for chronic cases, antivirals, vaccination recommended.

Lassa Virus

  • Pathogenicity: Causes Lassa fever, affects multiple body systems.
  • Transmission: Contact with infected rodent excreta, person-to-person through secretions.
  • Diagnosis: Clinical symptoms can mimic other diseases; confirmed via specialized assays.
  • Treatment: Ribavirin effective if administered early.

Food-Borne Diseases

  • Common pathogens include Novoviruses, Salmonella, and E. coli.
  • Fecal-oral route is main transmission path; poor hygiene practices are significant risk factors.
  • Symptoms include diarrhea, vomiting, and abdominal pains.
  • Control: Proper cooking, hygiene, and food handling practices are crucial.