Module 7 Flashcards
what is the most likely explanation for increasing antibiotic resistance in community-acquired disease?
a - patients not completing prescribed therapy
b - gram negative outer membrane permeability
c - generic branding and import medicines
d - overuse of antibiotics in farming and industry
e - metronidazole resistant spore forming anaerobes
d - overuse of antibiotics in farming and industry
what are the clinical characteristics of IDEAL ANTIBACTERIAL agents
- bacterioCIDAL
- oral & injectable
- long half-life
- low binding to plasma proteins
- good distribution
- minimal side effects
- lack adverse interactions
- narrow spectrum
penicillin V is usually described as ___ spectrum
narrow
isolation of clinical strains of bacteria resistant to specific antibiotics typically occurs within ____ of introduction of specific antibiotic therapy
several years
t/f genes that code for antibiotic resistance were in the gene pool before humans began to produce antibiotics
true
who performed the ‘replica plate’ experiment
Joshua Lederberg
what is the recent new bacterial “superbug”
carbapenem-resistant Klebsiella pneumoniae
what is carbapenem
beta-lactam antibiotic with BROAD spectrum activity against bacteria resistant to penicillins and cephalosporins
what are the steps of laboratory antibiotic susceptibility test
bacteria is streaked on a plate, then antibiotic-impregnated discs are put on the plate & incubated overnight to allow growth
what is the lowest concentration of antibiotic which prevents growth in presence of antibiotic
minimum inhibitory concentration (MIC)
what is the lowest concentration of antibiotic which irreversibly kills bacteria
minimum bactericidal concentration (MBC)
bacteria in __ may be up to a thousand-fold ___ sensitive to antibiotics than bacteria in solution
biofilm, less
when should antibiotics not be prescribed? and what is the exception
- upper respiratory tract infection
- strep throat, or cough lasting 10 days +/- advanced sinusitis
antibiotics must be selected based on ___ responsible for common clinical syndrome & ___ about antibiotic susceptibility within 48 hours
- presumed bacterial species
- current knowledge
when will referrals to an ID specialist or in patient therapies be necessary
if infections do not respond to more routine presumptive approaches or progress
~24 hrs
when should antibiotics be used in dentistry
- apparent & high potential infections
- few clinical syndromes
- young or elders or immunocompromised
- history of infection
most oral-facial infections are ___ of normal flora, resistance to ___ is not common. ____ will often be all that is needed
- mixed anaerobes
- beta-lactams
- draining of lesions
what are the limited clinical situations that require antibiotic therapy
- oral infection accompanied by elevated body temperature
- evidence of systemic spread (lymphadenopathy & restricted jaw movement)
- facial cellulitis
- aggressive acute necrotizing ulcerative gingivitis
- lateral periodontal abscess
- acute pericoronitis with systemic signs
___ that may or may not be associated with dysphagia, is a serious disease that should be treated by antibiotics promptly because of the possibility of infection spread via lymph and blood circulation, with development of ___
- facial cellulitis (soft tissue infection)
- septicemia
___ alone is likely to be effective
drainage
antimicrobials are used prior to surgery/procedures only when:
- high risk of post-op infection
- contaminated wounds w soil or dirt
- serious or life threatening infection consequences
- immunocompromised
what are the 3 conditions where antibiotics are NO LONGER recommended
- mitral valve prolapse (MVP)
- rheumatic heart disease (RHD)
- bicuspid valve disease
what are the 4 condition where antibiotics are STILL RECOMMENDED
- artificial heart valves or parts
- previous history of infective endocarditis
- some congenital heart conditions
- heart transplant recipients w/ valve problem
in general, for patients with prosthetic joint implants, prophylactic antibiotics are ____ prior to dental procedures to prevent prosthetic joint infection
not recommended
what are the most commonly used antibiotics by dentists
beta-lactam
beta-lactam antibiotics have activity against bacterial species often present in ____
purulent infections of head & neck
beta-lactam antibiotics come in __ or __ administration
oral & intramuscular
benzyl penicillin (penicillin G) is ___ so best when administered ___ because ___ from digesting a meal can inactivate much of this drug
- acid labile
- parenterally (IM injection)
- gastric acid
penicillin V, phenoxy methyl penicillin & amoxicillin are relatively ))) and more appropriate for oral administration - can be a 3 day course or discontinue after 72h if no issues
acid stable
what is commonly used by dentists because of its activity against anaerobic bacteria for periodontal disease and complications
metronidazole
what are the clinical characteristics of metronidazole
- oral absorption
- penetrates tissues
- very low resistance
- 5 day course
- no alcohol use
consider metronidazole if no improvement within ___ of penicillin (or amoxicillin)
48 hr
when is metronidazole used clinically
- acute ulcerative gingivitis
- rapidly progressive periodontal disease
- pt w serious spreading of anaerobic infection
what is often used instead of metronidazole for juvenile periodontitis
doxycycline
patients must not drink alcohol with ___ nor use ___
flagyl , warfarin
___ is only used in treatment of high risk or bone involvement
clindamycin
what are common alternatives to beta-lactam antibiotics
- erythromycin
- azithromycin
- clarithromycin
- clindamycin
orally administered & inhibit protein synthesis
___ are an equally good alternative but only when ____ is known or suspected
quinolones, gram negative beta-lactam resistance
what is an adverse effects of tetracycline on teeth
permanently discolors developing teeth (grey-brown to yellow)
so not used in pregnant pts or children
*** doxycycline does not cause this
tetracyclines may still be a drug of choice for __
some chlamydial or mycoplasma obligate intracellular bacterial infections
what is an antimicrobial agent for post treatment rinse
chlorhexidine diacetate (DCA)
when is chlorhexidine diacetate used
2X daily in recovery from gingivitis, periodontitis, dental traumas, oral cysts, and after wisdom tooth extraction
chlorhexidine has ___ activity against many ___ and ___ oral bacteria
bacterioCIDAL, gram +, gram -
what are the 3 major effects of fluoride
- systemic effect
- antimicrobial effect
- topical effect
what is the effect of incorporation of ingested fluoride into developing enamel as fluorapatite which reduces its solubility in acid and promotes remineralization
systemic effect
what is the effect of fluoride inhibiting plaque metabolism and concentrating within plaque, with activity increasing at pH values <5
antimicrobial effect
what is the effect of the surface layer of enamel being converted into fluorapatite reducing its solubility in acid and promoting remineralization
topical effect
the antimicrobial effect is by inhibition of ___
enolases - bacterial glycolytic enzymes
fluoride reduces cavities by ___ %
20-60%
what can be taken simultaneously with antibiotics and speeds up the restoration of normal flora
probiotics
bacterial antibiotics can significantly reduce ___
normal flora
what can cause oral candidiasis when normal bacterial flora is reduced by antibiotic therapy
Candida fungus
Clinical dentistry indicates the use of antibiotics in all of these situations. Choose the one where antibiotics are not routine:
a - anaerobic soft tissue abscess in a healthy patient
b - oral infection with elevated temperature or swollen lymph node
c - recognized named clinical infection syndrome or lesion type
d - otherwise fragile or patient with multiple co-morbidities
e - soil in a oral wound
a - anaerobic soft tissue abscess in a healthy patient
Guidelines on the prophylatic use of antibiotics in routine dental procedures have changed through the years, resulting in confusion about this. Indicate which of these REMAINS one of the instances where antibiotics are used prior to invasive dental procedures:
a - history of infective endocarditis
b - heart murmur
c - mitral valve prolapse
d - bicuspid valve disease
e 0 prosthetic joint replacement
a - history of infective endocarditis
metronidazole is a very useful drug with low resistance because of its mechanism of action. Which is a limitation of its use?
a - it only works on aerobic infections that are not abscesses
b - it only works on microbes growing anaerobically
c - it is not compatible with patients unlikely to comply with instructions not to mix with drinking
d - both b & c
e - none of these
d - both b & c
T/F: beta-lactams are simply never an option when it comes to someone indicating they may have had an allergy to penicillin as a child
false
