Ch. 5 Flashcards
Problems assoc. with malnutrition?
MC immune deficiency; leads to infection
Microflora within stomach?
Virtually sterile; some GPCs, some yeast
Microflora within proximal small bowel?
10^5 bacteria, mostly GPCs
Microflora within distal small bowel?
10^7 bacteria, GPCs, GPRs, GNRs
Microflora within colon?
10^11 bacteria, almost all anaerobes, some GNRs, GPCs,
Most common organism in GI tract?
Anaerobes; MC than aerobic bacteria in the colon (1,000:1)
What makes bacteria anaerobic?
Needing a low-oxygen environment (lack superoxide dismutase and catalase, making them vulnerable to oxygen free radicals)
MC anaerobe in the colon?
Bacteroides fragilis
MC aerobic bacteria in colon?
E. Coli
MC fever source within 48 hours?
Atelectasis
MC fever source within 48 hours - 5 days?
UTI
MC fever source after 5 days?
Wound infection
MC cause of Gram (-) sepsis?
E. coli
Pathophysiology of Gram (-) sepsis?
Endotoxin triggers the release of TNF-alpha (most potent stimulus; released from macrophages, triggers inflammation), activates complement, and activates coagulation cascade
What is the cause of Gram (-) sepsis)
Release of endotoxin (lipopolysaccharide lipid A)
Metabolic findings in Early gram (-) sepsis?
low insulin elevated glucose (impaired utilization)
Metabolic findings in Late gram (-) sepsis?
elevated insulin elevated glucose (secondary to insulin resistance)
What often occurs just before a patient becomes clinically septic?
Hyperglycemia
What is the optimal glucose level in a septic patient?
80-120 mg/dL
What are the signs of C. diff?
foul-smelling diarrhea; leukocytosis (often in 30-40’s); nursing home or ICU patients
How to diagnose C. diff?
ELISA for toxin A
Treatment for C. diff?
Oral - vamcomycin or Flagyl IV - Flagyl Fluid resuscitation Stop other antibiotics or change them Lactobacillus can also help
Treatment of C. diff in pregnancy?
oral vancomycin ( no systemic absorption)
What is fulminant pseudomembranous colitis? Treatment?
C. diff with severe sepsis, perforation
Tx: total colectomy with ileostomy
What percentage of abdominal abscesses have anaerobes?
90%
What percentage of abdominal abscesses have both anaerobic and aerobic bacteria?
80%
How are abscesses treated?
Drainage
When do abscesses normally occur following an operation?
7-10 days
When are antibiotics indicated for abscesses?
Patients with diabetes, cellulitis, clinical signs of sepsis, fever, or who have bioprosthetic hardware (mechanical valves, hip replacements)
Example of clean operation; percentage surgical site infection?
Hernia; 2%
Example of clean contaminated operation; percentage surgical site infection?
elective colon resection with prepped bowel; 3-5%
Example of contaminated operation; percentage surgical site infection?
gunshot wound to colon with repair; 5-10%
Example of grossly contaminated operation; percentage surgical site infection?
abscess; 30%
What is done to prevent surgical site infections?
Prophylactic antibiotics given within 1 hour of incision; stop within 24 hours of end operation time (except cardiac - stopped within 48 hours)
MC organism involved in surgical site infections?
Staph aureus - coagulase (+)
vs.
Staph epidermidis - coagulase (-)
What is released by Staph species that makes them stick around?
Exoslime (exopolysaccharide matrix)
What is the MC GNR in surgical wound infections?
E. coli
What is the MC anaerobe in surgical wound infections?
B. fragilis
What is the concern if B. fragilis is recovered from tissue?
Indicates necrosis or abscess ( only grows in low redox state); also implies translocation from gut
How many organisms needed for a wound infection?
> = 10^5 bacteria; less needed if a foreign body present
What are some risk factors for wound infections?
long operations hematoma or seroma formation advanced age chronic disease (eg, COPD, liver/renal failure, DM) malnutrition immunosupressive drugs
Considerations if have a surgical infection within 48 hours of procedure?
Injury to bowel - with a leak
Invasive soft tissue infection - Clostridium perfringens and beta-hemolytic strep can present within hours post op ( produce endotoxins)
MC infection in surgery patients?
UTI
- biggest risk factor are urinary catheters
- MC E. Coli (GNRs)
What is the leading cause of infectious death after surgery?
Nosocomial pneumonia
What is the biggest risk factor for nosocomial pneumonia following surgery?
Length of ventilation
Aspiration from duodenum thought to have a role
What are the most common organisms in ICU PNA?
#1 Staph aureus #2 Pseudomonas #3 E. Coli
What are the #1 class of organisms implicated in ICU PNA?
GNRs
