Microbiology & Antimicrobials Flashcards
name a gram positive cocci bacteria and give the colour and shape
s. anginosus
purple
round
name a gram negative cocci bacteria and give the colour and shape
veillonella species
red / pinkish
round
name a gram positive bacilli bacteria and give the shape
actinomyces israelii
rod shaped
name a gram negative bacilli bacteria and give the shape
prevotella intermedia
what does aerobic mean
requires oxygen
what does capnophilic mean
requires carbon dioxide
what does facultative mean
can grow with and without oxygen
what does strictly anaerobic mean
grows without oxygen
oxygen might even be toxic for these bacteria
what antibiotic works on strict anerobes
metronidazole only
how does antimicrobial resistance occur
occurs when microorganisms such as bacteria, viruses, fungi and parasites change in ways that render the medications used to cure the infections they cause ineffective
what are the 2 types of resistance
intrinsic resistance
acquired resistance
- mutation
- acquisition of new DNA
name mechanisms of antibiotic resistance
changes to the target site (binding proteins of the antibiotics no longer able to bind to the bacteria)
enzymatic inactivation (enzymes destroy antibiotics or prevent binding to target sites eg beta lactamase enzyme destroys the antibiotic)
decreased uptake
what is an endogenous infection
= bacteria thought to originate from our own endogenous flora (minority)
As opposed to the exogenous type of infections you can get from classic pathogens such as staphoreous (although some people believe you can get cross infection from certain organisms in the acute dental abscesses)
give examples of bacteria found in acute dento-alveolar infections
streptoccus anginosus
prevotella intermedia
what are the treatment principles of dental abscesses
localised infection
establish a diagnosis - need to take a good history and carry out a thorough examination
document it
remove the source of the infection
what is the microbiology of pericoronitis
predominantly mixed oral anerobes eg P intermedia
S. anginosus group
what is treatment of pericoronitis
local measures
antibiotics only if there is systemic signs and symptoms
treatment of dry socket
does not require antibiotic treatment
treatment is under LA
Debridement
packing with antimicrobial gels or gauze strips
what is osteomyelitis predisposed by
MRONJ
impaired vascularity of bone due to radiotherapy or pagets disease
foreign bodies (implants)
compound fractures - communication either intra- or extra-orally
impaired host defence - diabetes
microbiology of osteomyelitis of the jaws
anaerobic gram negative rods
anerobic streptococci
streptococcus anginosus
staphylococcus aureus (any infection in the bone we worry about S. aureus infections as this affects the choice of antibiotic we can use and usually require a long course)
microbiology of salivary gland infection
s. aureus
mixed anaerobes
treatment of salivary gland infection
drainage
flucloxacillin and metronidazole
what must you always do in the context of acute alveolar infections
- document diagnosis following history and examination
- document antibiotic choice, dose, route and duration
- document a review date (for an acute infection it usually should be within 24-48 hours)
- document deviation from guidance
what is SOI
Severe odontogenic infection
what is ludwigs angina
bilateral infection of the submandibular space
most common bacteria: anaerobic gram negative bacilli (P. intermedia), steptococcus anginosus, anaerobic streptococci
what is sepsis
infection + SIRS
What is SIRS
systemic inflammatory response syndrome
2 or more of:
1. temp <36 or >38
2. pulse >90/min
3. resp rate >20/min or (PaCO2 <4.3)
5. WCC <4 or >12
are antibiotics used to treat sepsis
yes
the sooner you administer antibiotics the greater the chance of the patient surviving sepsis
but reassess antimicrobials daily:
- optimise
- reduce resistance
- avoid toxicity
- reduce costs
what is sepsis
life threatening organ dysfunction caused by dysregulated host response to infection
what is septic shock
sepsis + unresponsive to fluid resuscitation
subset of sepsis with circulatory and cellular / metabolic dysfunction associated with higher risk of mortality
what are the treatment principles for SOI and ludwigs angina
primary care
- diagnosis
- seek advice / help
secondary care
- diagnosis
- sepsis 6
- national early warning score (NEWS-2)
what is the sepsis 6
- give high flow oxygen
- take blood cultures
- give IV antibiotics
- give a fluid challenge
- measure lactate
- measure urine output
what is a break point
chosen concentration (mg/L) of an antibiotic which defines whether a species of bacteria is susceptible or resistant to the antibiotic
what is clinical resistance
when infection is highly unlikely to response even to maximum doses of antibiotic
what are confounding variables of resistance in the lab
- inoculum size, growth phase, planktonic, pH, atmosphere
- breakpoint calling
- biofilm
what are confounding variables of resistance clinically
co-morbidities, pus collections, foreign bodies, site of infection
biofilm
pharmacokinetics
pharmacodynamics
what are pharmacokinetics
how antibiotics are distributed through the body
what are pharmacodynamics
how the antibiotic classes interact with the bacteria
what is antimicrobial stewardship
preserve antimicrobial medicines by taking measures to promote their control
3 ways to contribute to antimicrobial stewardship
- prevention of dental disease
- prevent spread of disease (wash hands / SICPS / get vaccinated against the flu)
- antibiotics dont cure toothache
