Microflora Flashcards
What are some Gram-positive bacteria found on the skin?
- Coagulase -ve Staphylococcus (i.e. Staphylococcus epidermidis)
- Staphylococcus aureus (the only coagulase +ve Staph. = pathogenic)
- various species of Streptococcus
What are some Gram-negative bacteria that is found on the skin?
- Acinetobacter
What are some fungi found on the skin?
- Candida
What are some normal flora found in the nose?
- Staphylococcus aureus
- Staphylococcus epidermidis
What are some normal flora found in the nasopharynx?
- Streptococcus pneumoniae
- Neisseria meningitidis
What are some normal flora found in the oropharynx?
various Streptococci
What causes infection in the lower repiratory tract?
- the larynx, trachea, bronchioles, lower airways are sterile
- transient colonisation with secretions from the upper respiratory tract (S. aureus, S. pneumoniae, etc.)
Opportunistic pathogen of the GI tract?
- Clostridium difficle is usually found within the GI tract, but if GI tract is disrupted by antibiotics, an opportunity is provided for C. difficle to transiently colonise
What can cause infection of the esophagus?
- Candida spp.
- viruses (Herpes simplex virus, etc.)
What is normal flora of the stomach?
- acid-tolerant bacteria
: lactic acid-producing bacteria (Lactobacillus & Streptococcus spp.)
: Helicobacter pylori
What are some normal flora of the small intestine?
- mostly anaerobes
- Salmonella & Campylobacter spp. (common cause of gastroenteritis)
What are some normal flora of the large intestine?
- mostly anaerobic
- most common
: Bifidobacterium
: Eubacterium
: Bacteroides
: Enterococcus
: Enterobacteriaceae
What are pathogens that cause urethritis?
- Neisseria gonorrhoea
- Chlamydia trachomitis
What is some microflora of the vagina?
Candida albicans
: overgrowth causes disease
What are some factors that increase susceptibility to infections?
- age (i.e. elderly/children)
- defects in immune response
- pre-existing medicial conditions (i.e. diabetes)
- immunosupression
- malnutrition
- transplantation (immunosupression)
- preosthetics
What does Clostridium tetani, Clostridium botulinum & Clostridium difficile cause?
- Clostridium tentani: tetanus
- Clostridium botulinum: food poisoning
- Clostridium difficile: colitis & diarrhoea
Define normal flora
- microorganisms that live on other living organisms / inanimate objects without causing disease
- able to cause disease if exposed in unusual locations or to immunocompromised persons
Resident flora vs Transient flora
Resident flora: usuallu occupy a particular body site
Transient flora: are not established permanently on/in people
What is the importance of normal flora?
- aid in breaking down food
- provides growth factors
- protects against some infections
- stimulates immune response
What is the importance of understanding normal flora?
- can give an idea of possible infections that can arise from injury at a site
- give an idea of possible sources of infection
- provide understanding of a host’s immune response
What is an example of normal flora within the oral cavity & what infection/disease does it cause
Streptoccocus mutans can cause dental decay
Define Nosocomial Infection & give examples
infection that occurs with prolonged or frequent hospital stay e.g.
- VANIs (Ventilator Associated Nosocomial Infections)
- NUTIs (Nosocomial Urinary Tract Infections)
- NRTIs (Nosocomial Respiratory Tract Infections)
- HAIs (Hospital Acquired Infections)
What should normal flora of the skin be resistant to?
- acidic pH
- periodic drying
- high NaCl concentration (from sweat)
- other inhibitory substances
