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35 Cards in this Set
- Front
- Back
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What was present in the first samples from Cathy's first hospital stay?
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Escherichia coli
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What was her abdominal pain attributed to? What was done about it?
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Attributed to peritonitis; peritoneal dialysis was stopped and subclavian hemodialysis 3 times a week was begun.
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What medication was Cathy continually administered that was not getting rid of the infection?
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Ciprofloxacin (IV)
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What was Cathy's initial diagnosis?
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Peritonitis. Treated with Ciprofloxacin.
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What was Cathy hospitalized for the third time?
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Sepsis
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What were the two possible reasons for Cathy's illness prevaiing over the repeated courses of Ciorofloxacin?
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1. The infecting organism had become resistant to fluoroquinolones
2. She had a concurrent infection with anaerobic bacteria (fluoroquinolones have only marginal affect) |
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What was the cause of Cathy's acute respiratory distress and hypotensive nature?
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The physician who intubated her attributed it to an overwhelming Gram-negative sepsis.
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What was seen in the first culture aside from E. coli upon reinspection?
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Bactericides fragilis
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What did the infectious disease consultant find in her literature review concerning Cathy's case?
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That B. fragilis is always secondary to bowel rupture and concluded that the severe pain Cathy felt in October was caused by ruptured bowel.
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What was administered in place of the Ciprofloxacin and why?
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Metronidazole by IV because anaerobic bacteria such as Bacteroides are susceptible to it but not to Ciprofloxacin.
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What other quinolones are recommended in addition to metronidazole in treating abdominal anaerobic infections?
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Levofloxacin or moxifloxacin
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What were other complications of infection in Cathy's case?
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**Systemic sepsis (caused by unknown organism--possibly B. fragilis)
**Methicillin-resistant Staph aureus (MRSA)--treated with IV vancomycin **Systemic candidiasis--treated with amphotericin B |
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How did the systemic candidiasis start?
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Antibiotics supress the normal flora allowing for overgrowth of Candida albicans, which produce hydrolytic enzymes and proteinases that damage and digest human cells
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What is Stevens-Johnson syndrome?
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A life-threatening reaction (adverse drug reaction) to antimicrobials--leads to massive skin loss and huge, weeping wounds. Mortality rat is 5-15%
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Which infections are of particular concern with prevalence expected to rise?
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MRSA
Vancomycin-resistant enterocci (VRE) Vancomycin-resistant Staph aureus (VRSA) ESBLs |
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What does ESBL stand for? What is the action of ESBLs?
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Extended spectrum B-lactamases.
ESBLs produced can inactivate multiple classes of antibiotics by breaking down the B-lactam that interferes with the formation of bacterial cell walls. |
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Give 3 examples of ESBLs
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E.coli
Kelbsiella pneumoniae Enterobacter |
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Give 3 examples of antibiotics inactivated by ESBLs
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Penicillins
cephalosporins aztreonam |
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How much of a drug is needed in order to treat an infection that is not sensitive to that drug?
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No amount--not even the toxic amount--will have the desired effect on the infection.
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What is a superinfection?
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A superinfection is a new infection that is caused by a virus, bacterium, or fungus different from the initial cause of infection--occurs when the normal flora of a patient is sensitive to the antimicrobial and is killed off.
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Give an example of a superinfection in Cathy's case.
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Systemic candidiasis
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What can Clostridium difficile result in?
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Severe diarrhea, pseudomembranous colitis, and other life-threatening complications.
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What is the number-one cause of nosocomial infectious diarrhea?
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C. difficile
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What are 2 ways bacteria can develop resistance?
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1. Spontaneous gene mutation
2. Transfer of genetic material from a resistant organism to a susceptible one |
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Name two examples of a rare case of only a single mutation conferring significant resistance.
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Rifampin resistance in S. aureus
Flouroquinolone resistance in Campylobacter jejuni |
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What is horizontal gene transfer? How does it occur?
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The sharing of genetic material and antimicrobial resistance--done through conjugation, transformation, and transduction
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What occurs during the process of conjugation?
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Genetic materials in the form of plasmids transfer from one bacterium to another.
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What is a plasmid?
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A plasmid is a circular piece of genetic material that often carries a resistance gene and is independent of the chromosomes of the bacterial host cell.
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How does VRE become resistant?
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By acquiring vanA and vanB resistance genes from other bacteria through conjugation.
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How does the ability to produce ESBLs develop?
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Through conjugation
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Explain transformation
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Bacteria incorporate genetic material released by dead bacteria into their own chromosomes or plasmids
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What is transduction?
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A bacteriophage infects a bacterial cell by taking over the reproductive mechanism of the bacterium and replicating its own DNA/RNA, producing more virus particles.
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How do bacteria develop resistance?
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**Inactivation of antimicrobial (beta-lactamases)
**Active removal (efflux) of antimicrobial **Changes in cell walls (thickening) **Changes in cell wall binding site **Changes in drug target sites **Development of alternative metabolic pathways |
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T of F: Beta-lactamase producers only have one mechanism of action and therefore can only inactivate one type of antimicrobial (penicillins)
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FALSE. They do only have one mechanism of action, but beta-lactamases are multidrug resistant (namely, cephalosporins, penecillins, and azteronam)
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What drugs do carbapenem-hydrolyzing enzyme producers affect?
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Imipenem (Primaxin)
Meropenem (Merrem) |
