Intro to antimicrobial therapy Flashcards
What is the normal flora of the oral cavity?
Streptococci viridans, sanguis, mutans, Lactobacilli, Staph (aureus and epidermidis), Corynebacterium sp., Bacteroides sp., Actinomyces sp.
What is the normal flora of the nose?
Staph epidermidis/aureus, Corynebacteria, Neisseria sp., Haemphilus sp, Strep pneumoniae
What is the normal flora of the nasopharynx?
Non-hemolytic streptococci/Alpha-hemolytic streptococci. Strep pneumoniae and pyognenes,
H. influenzae, Neisseria meningitidis
What is the normal flora of the lower respiratory tract?
Usually sterile. The individual becomes infected by the pathogen descending from the nasopharynx
What is the normal flora of the external ear?
Staph epidermidis/aureus and Corynebacterium sp.
What is the normal flora of the GI tract?
Enterobacteriaceae, Enterococci, Bacteroides, Staphylococci, Lactobacilli, Clostridia. usually anaerobic and gram negative
What is the normal flora of the urethra?
Staph epidermidis, Enterococcus faecalis, Alpha-hemolytic streptococci, E coli, Proteus, Corynebaceria sp, Acinetobacter sp, Mycoplasma sp, Candida sp, Mycobacterium smegmatis
What is the noraml vaginal flora?
Corynebacterium sp, Staphylococci, Nonpyogenic streptococci (Group B strep), E coli, Lactobacillus acidophilus, Flavobacterium sp, Clostridium sp, Viridans streptococci,
What is the MIC (minimum inhibitory conc)?
Lowest concentration of antimicrobial that inhibits growth of bacteria.
What is the breakpoint?
The MIC that is used to designate between susceptible and resistant.
What are mechanisms of antibiotic resistance?
Enzymatic inactivation. Antibiotic uptake reduction. Increased antibiotic removal. Alteration of bacterial target sites
Describe how beta-lactamases degrade antibiotics
Bacterial enzymes that split the beta-lactam ring of penicillin, cephalosporins, carbapenems and monobactams. Aminoglycoside, ciprofloxacin and trimethoprim-sulfamethoxazole resistance often all on same plasmid
What patient factors modify drug choice?
For maximal efficacy the antibiotic must be present at the site of infection in a concentration greater than the MIC. Drug penetration may be hampered depending on the site of the infection (soft tissue vs. bone)
What are patient consideration to determine high risk for less common or resistant pathogens?
Medical history, Travel history, Antibiotic use in the last 3-6 months, Residing in a long term care facility
What are the different ways to isolate a bacteria?
Rapid antigen testing. Wound culture and sensitivity. Throat culture. Sputum culture. Blood cultures
What are appropriate measures of drug therapy?
Start empiric antibiotic therapy. Use as narrow a spectrum drug as possible. If patient is very ill or source of infection is unclear choose broader spectrum. When culture and sensitivity results are known change antibiotic if necessary. Consult antibiogram