gram positive bacteria

what colour are gram positive bacteria after a gram stain?

purple

what are the two main shapes of gram positive bacteria?

- cocci

- bacilli

what are the two most common gram positive cocci?

- staphylococci

- streptococci

where can staphylococci and streptococci infect?

human throat, nose and skin

are staphylococci and streptococci generally antibiotic resistant or sensitive?

sensitive

are staphylococci and streptococci generally antiseptic resistant or sensitive?

sensitive

are staphylococci and streptococci resistant or sensitive to drying?

resistant

how are staphylococci further subdivided?

coagulase test

what does the coagulase test separate between?

pathogenic and non-pathogenic (commensal) staphylococci

what result do pathogenic staphylococci produce from the coagulase test?

positive

why are pathogenic staphylococci coagulase positive?

they produce an enzyme that clots plasma

what is an example of a coagulase positive staphylococci?

staphylococcus aureus

what is staphlococcus aureus usually sensitive to? (6)

beta lactamase producers:

- flucloxacillin

- clindamycin

and

- clarithromycin

- doxycycline

- nitrofurantoin

- rifampicin

what result do non-pathogenic staphylococci produce from the coagulase test?

negative

do non-pathogenic staphylococci have the potential to become pathogenic?

yes via opportunistic infections

how are streptococci classified?

haemolysis on blood agar

what are the 2 main types of haemolysis by streptococci

- beta

- alpha

what is beta haemolysis?

total breakdown of blood agar = pathogenic

what is alpha haemolysis?

partial breakdown of blood agar = commensal

what are beta haemolytic streptococci subdivided into?

groups A, B, C etc

what antibiotic are both alpha and beta-haemolytic streptococci sensitive to?

pencillin

what are three gram positive infections of the skin?

- abscesses (staphylococci)

- cellulitis (streptococci)

- wound infections (both)

what are two gram positive infections of the respiratory tract?

- upper = pneumococci

- lower = pneumococci

what are three other types of gram positive infections?

- osteomyelitis (staphylococci)

- septic arthritis (staphylococci)

- endocarditis (streptococci)

what are some narrow spectrum gram positive antibiotics for streptococci? (7)

- penicillin

- clindamycin

- clarithromycin

- doxycycline

- rifampicin/vancomycin

- amoxycillin (for enterococci)

what are some narrow spectrum gram positive antibiotics for staphylococci?

- flucoxacillin

- clindamycin

- clarithromycin

- doxycycline

- rifampicin/vancomycin

what is the main example of a gram positive bacilli?

clostridia

is clostridia aerobic or anaerobic?

anaerobic

are clostridia toxigenic?

yes

what is the most common clostridia?

clostridiodes difficile - causing colitis

what are the main antibiotic treatments for clostridia?

- vancomycin (c. diff)

- penicillin

- metronidazole

how else can clostridia be treated?

- vaccines e.g. tetanus

- antitoxins