MICROBIOLOGY Flashcards
What colour are gram positive bacteria?
Purple
What colour are gram negative bacteria?
Pink
How do we gram stain?
Fixation -> crystal violet->iodine treatment->discolouration -> counter stain with safranin
What are two types of gram positive cocci?
Staphylococcus (clusters)
Streptococcus (chains)
What differentiates between staphylococcus and streptococcus?
Staph= catalase positive Strep= catalase negative
What does haemolysis on blood agar differentiate?
Alpha and beta streptococci
What colour do haemolysis blood agar test?
Alpha- greening
Beta- clearing
What does the optochin test distinguish?
It distinguishes between optochin sensitive and resitant gram positive alpha streptocci
What is a optochin sensitive alpha streptococci?
S.Pneumoniae
What is a optochin resistant alpha streptococci?
S.viridans
What test distinguish different beta streptococci and which result is important?
The Lancefield group (A,B,C,D) with A being S.Pyogenes
How are staphylococcus distinguished?
The coagulase test
What does a positive coagulase positive test indicate?
S.Aureus
What staphylcoccus are negative on the coagulase test?
S.epidermidis and S.saprophiticus
What are the 2 types of gram positive bacilli?
Aerobic (listeria monocytogenes) and anaerobic (c.diff)
what bacteria are gram negative cocci?
N. gonorrhoea and N. meningitidis
What distinguishes gram negative bacilli?
MacConkey plate grows lactose fermenters and non-lactose fermenters
What colour are lactose fermenters?
Pink
What bacteria are lactose fermenters?
Gram negative bacilli such as E.coli and Kelbsiella pneumoniae
What test distinguishes non- lactose fermenters?
Oxidase test
What do the results of the oxidase test show?
Negative indicates enterobacteria and psuedmonas such as p.aeruginosa
Which antibiotics inhibit cell wall synthesis?
Glycopeptides and beta lactams
What type of antibiotic in vancomycin?
It is a glycopeptide that inhibits cell wall synthesis
What are examples of beta lactams?
Penicilins (flucoxacillin and amoxicillin)
Cephalosporins (cephalexin, cefuroxime) and carbapnems (imipenem, ertapenem)
What does trimethorpim do?
It inhibits folate synthsis
What does fluroquinolones do?
Inhibit DNA gyrase
What does rifampicin do?
It binds to RNA polymerase to inhibit nucleic acid synthesis
What does metronidazole do?
It breaks the DNA strand
Which antibiotics inhibit protein synthesis?
Clarithromycin, erythromycin and gentamycin
What system determines the severity of pneumonia?
CURB65
Which bacterial pneumonia is associated with HIV?
Pneumocyctis jiroveci
What is a complication of COPD?
Pneumonia caused by haemophilus influenza
What bacteria causes legionnaires pneumonia?
Legionella pneumophilia
What antibiotics are used to treat UTIs?
Trimethoprim or nitrofurantroin
What infection spreads upwards from a UTI causing loin to groin pain?
Pyelonephritis
What bacteria causes cellulitis?
s.pyogenes and s.aureus
What antibioctics are used to treat cellulitis?
flucoxacillin
What would give to someone with suspected sepsis?
15L oxygen
Fluids
Broad spec antibiotics
Sepsis warning signs?
Shivering, Extreme pain, Pale, Sleepy/confused, Impending doom, Sob
Name an anti- emetic and an anti-diarrhoeals?
prochlorperazine
loperamide
What antibiotics would you give to someone with infective endocarditis?
Amoxicillin and gentamicin
What are signs for infective endocarditis?
Roth spots, splinter haemorrhages, Osler’s nodes and Janeway lesions
What valve does IVDU effect most commonly?
Tricuspid valve
Which antibiotics cause c.diff?
Co-amoxicalv, Clindomycin, Cephaslosporins, ciprofloxacin and carbapenems
What is the treatment for c.diff
oral vancomycin or metronidazole
What medication is linked to c.diff?
PPI
What is the treatment of mycobacterium tuberculosis?
Rifampicin, Isoniszid, Pyrazinamide, Ethambutol
What are the complications of the TB drugs?
Rifampicin- red urine, hepatitis
Isoniazid- Polyneuropathy
Pyrazimide- Gout, hepatitis
Ethambutol- Optic nueritis
What are the difference between gram positive and gram negative bacteria?
+have a thicker peptiglycan layer
+ have lipoteichoic acid on the outside
+ do not have lipopolysaccharides on the outside
- have 2 outer layers
What are enterobacteria?
E.coli, shigella and salmonella
What does vancomycin treat?
MRSA and gram +
What is used for atypical pneumonia and Gram + treatment?
Clarithromycin and erythromycin
What is the treatment for the chest infections?
Doxycyclin
What is the treatment for UTIs?
Trimethoprim and nitrofurantoin
What virus causes chicken pox and shingle?
Varicella zoster
What causes the black plague?
Yersina spp
What causes cholera?
Vibrio cholerae
What causes whooping cough?
Bordetella pertusis
What is the most common food poison cause?
campylobacter
