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35 Cards in this Set
- Front
- Back
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Steps Taken to ensure appropriate drug selection
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1. Establish presence of infection
2. Pathogen identification 3. Antibiotic therapy selection 4. Monitoring parameters 5. Antibiotic regimen changes. |
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skin
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• Staphylococci (CNS)
• Streptococci • Diphtheroids |
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GI tract
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• Enterobacteriaceae
• Bacteroides sp. • Clostridium sp. • Streptococci (anaerobic) • Enterococci |
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oropharynx
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• Streptococci
• Neisseria sp. • Haemophilus sp. • Bacteroides sp. (anaerobes) |
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genital tract / GU
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• Enterobacteriaceae
• Lactobacillus sp. • Staphylococci |
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Gram negative cocci
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neisseria gonorhea
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Staphylococcus aureus, staph epidermis, strep pneumoniae, strep pyogenese (beta hemolytic or group A strep), enterococci (E faecalis, E faecium)
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Gram positve cocci
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Acid Fast
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• Mycobacteria (e.g., M. tuberculosis, M. avium complex)
• Cryptosporidia • Nocardia (weakly acid-fast) |
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• Commensals
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o Normal flora – live in concert with the host; under normal circumstances, these do not cause infection
o Colonize all “external” parts of the body – external would refer to access to the outside world, so the respiratory tract and GI tract are included in the “external” definition. |
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• Professional pathogens
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– really only role as far as humans are concerned are as infectious agents
o Efficient entry into body o Capable of rapidly multiplying o Not part of normal flora |
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• Opportunistic pathogens
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o Require a breach in the immune system to gain entry
o Often part of normal flora |
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lactobacillus, diphtheroids (corynebacteria), C diff
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gram positive bacilli
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enterobacter: e coli, kleb, proteus
pseudomonoas aeruginosa |
gram negative bacilli
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“gold standard” for identification
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culture
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serology for “difficult-to-isolate” organisms
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• Immunologic Detection
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superficial fungal infections
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• KOH/wet mount
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occur in clusters
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• staphylococci
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occur in short chains
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• streptococci
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occur in pairs
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• diplococci (e.g., Streptococcus pneumoniae, Neisseria sp.)
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Coagulase properties (Staph)
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Coagulase is a protein enzyme that allows for the conversion of fibrinogen to fibrin. Whether an organism does or does not produce this enzyme can help in identification.
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• Coagulase-positive
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S. aureus
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• Coagulase-negative
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S. epidermidis
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Hemolytic properties (Strep)
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Hemolysis is the breakdown of red blood cells. This characteristic is particularly helpful in differentiating different Streptococcal species. When grown on blood agar, the organism can display complete hemolysis, partial hemolysis, or no hemolysis.
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• Beta-hemolysis
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complete hemolysis (Streptococcus pyogenes)
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• Alpha-hemolysis
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partial hemolysis
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• Gamma-hemolysis—
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no hemolysis (Enterococci)
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Gram-positive cocci, in chains:
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streptococcus
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Beta-hemolytic gram-positive cocci in chains:
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streptococcus
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Gram-postitive cocci, in clusters, coagulase negative:
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S. epidermis
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Gram-positive cocci, in clusters, coagulase positive:
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S aureus
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Gram-positive cocci, in pairs:
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Streptococcus pneumoniae
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• GMS
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stains fungal cell wall
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• Giemsa
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stains fungal cell contents
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for detection of superficial fungal infections of the skin, can be used for identification of vulvovaginal candidiasis (may help differentiate from other sexually transmitted infections)
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KOH/Wet Mount—
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Virus
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• Culture (**gold standard** but not routinely possible for all viruses)
• Tissue Culture—examine for cytopathic effect (e.g., intranuclear inclusions) • DNA Analysis (e.g., RT-PCR) • Immunologic Detection (e.g., serology for detection of Ab) |
