Bacteria and viruses Flashcards
What does steptocus pyogenes cause and whats its gram reaction?
Positive
Necrotising fascitis
Group B Streptococci
Psotive gram stain
Neonatal sepsis and meningitis
Streptococcus pneumoniae
Gram positive
Pneumonia (also meningitis, sepsis and endocarditis)
Neisseria meningitis
negative gram stain
Septicaemia and meningitis
Neisseria gonorrhoea
negative gram stain
Gonorrhoea which can lead to pelvic inflammatory disease and epididymitis
Escherichia coli
negative gram stain
watery diarrhoea, acute renal failure (haemolytic uremic syndrome)
salmonella spp.
negative gram stain
gastroenteritis, typhoid fever
shigella
negative gram stain
dysentery, blood diarrhoea
psuedomonas aeruginosa
negative gram staining
gerneralised inflammation and sepsis
legionella spp.
negative gram stain
pontiac fever, legionairres diesease (legionellosis)
-acute influenza or pneumonia
helicobacter pylori
negative gram staining
Causal role in peptic ulcers especially duodenal
Bacteroides spp.
negative gram stain
abscesses and lesions
chlamydia spp.
negative gram staining
chlamydia
mycobacterium tuberculosis
acid fast staining (cannot be identified using gram staining)
Tuberculosis
mycobacterium leprae
acid fast staining (cannot use gram staining to identify)
Leprosy
What is the difference between gram positive and gram negative bacteria?
Gram positive (dye blue) retain the crystal violet (blue) dye on staining and the acetone or methanol doesn’t wash it away as it has a thick peptidoglycan wall. Gram negative bacteria have an outer membrane lipopolysaccharide cell wall but only a thin peptidoglycan wall therefore the crystal violet dye washes away when acetone or methanol is applied, this then dyes red.
What antibiotics are contained within B-Lactams and what do they target?
Penicillin, amoxicillin, flucloxacillin and cephalexin
Target the cell wall
What drug is within the glycopeptide group and what does it target?
Vancomycin
Targets cell wall
What antibiotics target the cell wall of bacteria?
Penicillin, amoxicillin, flucloxillin, cephalexin (all B-Lactams) and Vancomycin (glycopeptide)
What antibiotics target protein synthesis?
Gentamicin (aminoglycoside), Erithromycin (macrolide), Tertacycline (polyketide),
What antibiotic affects DNA?
Ciprofloxacin (chemotherapeutic)
What drugs target Anti-folate?
Trimethoprim
Metonidazole
What antibiotic affects RNA polymerase?
Rifampicin
What does Staphyloccocus aureas cause and what is its gram stain classification?
Positive gram stain
Abcesses, toxic shock syndrome and food poisoning (may cause endocarditis and osteomyelitis if it enters the blood stream)
Which bacteria give a positive gram stain?
Staphylococcus aureas, streptoccus pyogenes, Group B sterptococci and steptococcus pneumoniae
Explain the process of gram staining
Crystal violet binds to negatively chaged cell components
Iodine forms a large molecular complex
Acetone/methane-positive bacteria have a thicker peptidoglycan layer, so they retain blue dye.
Red dye -GRAM NEGATIVE bacteria have a thinner peptidoglycan layer, so the alcohol washes the colour away, so extra staining required.
Clostridium perfingens
Positive gram stain
Gas gangrene
Clostridium difficile
Positive gram stain
Antibiotic associated diarrhoea (can lead to pseudomembranous colitis)
What does the drug penicillin act on and it what group is it classified?
Cell wall
B-lactams
What does amoxicillin target and what group?
Cell wall
B-lactams
Flucloxacillin
Cell wall
B-lactams
Cephalexin
Cell wall
B-lactams
Vancomycin
Cell wall
Glycopeptide
Gentamicin
Protein synthesis
Aminoglycoside
Erthromycin
Protein synthesis
Macrolide
Tetracycline
Protein synthesis
Polyketide
Ciprofloxacin
DNA
Chemitherapeutic
Rifampicin
RNA Polymerase
Trimethroprim and metronidazole
Anti-folate
