Bacterial Pathogens Flashcards
Staphylococcus aureus - key facts?
Mostly found in nasal carriage, causes skin and soft tissue infections.
What type of staphylococci is S. epidermidis?
coagulase negative
Where does S. Epidermis live and what does it cause?
Lives in skin and causes infection in association with ‘foreign bodies’ e.g. catheters.
Adheres via glycocalyx.
What is the other name for streptococcus pyogenes?
Group A Strep.
What do group A strep/ streptococcus pyogenes cause?
Sore throat. (also scarlet fever, necrotisig fasciitis, SSTI’s of skin, puerperal sepsis).
What does streptococcus pneumoniae cause?
Commonest cause of bacterial pneumonia. Commonest cause of bacterial meningitis (except in neonates). Can cause other childhood infection e.g. otitis media.
What is the other name for Streptococcus agalactiae?
Group B strep.
What does Streptococcus galactiae cause?
Commonest cause of bacterial meningitis in neonates (<3months).
What is the Streptococcus milleri complex?
3 closely related species of pus-forming streptococci. Associated with abscesses (dental, brain, lung, liver).
What are Viridans Streptococci and where do they live?
Collective name for a-haemolytic streptococci that inhabit the upper respiratory tract e.g. S. oralis, S. mitis.
What was Streptococcus Gallocyticus formerly known as and what is it?
Streptococcus bovis- a type - a-haemolytic streptococcus that forms part of bowel flora. Associated with colonic malignancies.
What is Listeria monocytogenes?
A gram positive bacillus whih is rare but signif cause of sepsis & meningitis in pregnancy, neonates & immunosuppressed patients.
What particular features does listeria monocytogenes possess?
Zoonosis (passed from humans to animals) and able to grow at low temps. Associated with consumption of unpasteurised dairy products.
What is Cornebacterium species and where does it live?
Gram positive bacilli, live in skin and URT.
What are corynebacterium associated with?
- Oppurtinistic infections associated w/ devices & trauma 2. Coonebacterium diptheria (rare as now have vaccines).
What is propionibacterium acnes?
Gram positive bacillus associated with acne. Can also cause device-associated infections.
What are enterobacheriaceae ‘coliforms’?
Collective term for gran negative bacilli found in bowel flora.
What does E. coli cause?
Commonest cause of UTI, Commonest cause of bacteraemia (urinary bialy & intr-abdo). Causes nosocomial infections. Toxigenic strain (e.g. O157) associated with severe diarrhoea and haemolytic uraemic syndrome (HUS).
What is Pseudomonas Aeruginosa
Multi-resistant gram negative bacillus. Can cause rest infection, UTI’s, skin & soft tissue infections. Often produces characteristic green pigment.
What is Neisseria meningitidis
It is a gram negative diplococcus which causes meningococcal sepsis and/or meningitis.
What is classic presentation of neisseria meningitidis?
Purpuris non-blanching rash (sepsis)
What is Neisseria gonorrhoeae?
Gram negative diplococci causeding gonorrhea, opthalmia neonatorum. Occasionally can cause invasive infections e.g. septic arthritis.
What is Haemophilus influenzae?
Gram negative bacillus which forms part of normal RT flora BUT can cause RTI’s e.g. pneumonia, infective exacerbations of COPD.
What are capsulated types (e.g. type b). of haemophilia influenzae associated with?
Meningitis and epiglottis. (only type b infections prevented by Hlb vaccine).
What are enterococci?
gram-positive cocci that tend to occur in pairs -> diplococci
What are HACEK organisms?
Group of gram negative bacteria e.g. haemophilus initially thought to be cause of infective endocarditis - now known as rare cause.
What do spirochetes cause?
Treponema pallidum causes syphilis. Other species cause leptospirosis and Lyme Disease.
What are three bacterium without conventional cell wall?
- Chlaymdia species - C. trachoma’s = commonest cause of STI.
- Mycoplasma species - M. pneumonia = commonest cause of RTI’s/ and
- Legionella pneumophila causing Legionnaire’s.
What are examples of anaerobes?
Clostridium species (Spore-forming), bacterioides species, Fusobacerium species, Prevotella species and others. Often part of polybacterial infections e.g. dental, absecesses, skin etc
What does C. difficile cause?
antibiotic-related diarrhoea/colitis
What does C. perfringens cause?
classical cause of gas gangrene.
What does C. tetani cause?
tetanus
What does C. botulinum cause?
Botulism.
What are Mycobacterium species often referred to as?
Acid Fast Bacillis (as they do not stain using conventional gram staining)
What does mycobacterium tuberculosis cause?
tuberculosis.
What do Atypical Mycobacteria cause?
Resp infections in those with chronic lung disease, in immunocompromised patients e.g. AIDS, transplant.
