Antimicrobial Therapy
ÎAntimicrobial therapy should be administered to all patients diagnosed with appendicitis (A-II).
ÎAppropriate antimicrobial therapy includes agents effective against facultative and aerobic Gram-negative organisms, streptococci and anaerobic organisms, as detailed in Tables 2 & 3 for the treatment of patients with community-acquired intra-abdominal infections (A-I).
ÎSuch therapy should be started when the diagnosis of appendicitis is confirmed by imaging techniques or when, in the absence of such confirmation, the decision is made to operate. This should occur in any case within six hours of presentation (B-II).
ÎAcute appendicitis without evidence of perforation, abscess, or local peritonitis requires only prophylactic administration of narrow spectrum regimens active against aerobic and facultative and obligate anaerobes, which should be discontinued within 24 hours (A-I).
ÎFor patients with suspected appendicitis whose diagnostic imaging studies are equivocal, antimicrobial therapy should be initiated along with appropriate pain medication and antipyretics. For adults, antimicrobial therapy should be provided for a minimum of three days, until clinical symptoms and signs of infection resolve or a definitive diagnosis is made (B-III).
Microbiology ÎGram stains may help define the presence of yeast (C-III).
ÎFor higher-risk patients, aerobic and anaerobic cultures should be routinely obtained, particularly in patients with prior antibiotic exposure who are more likely to harbor resistant pathogens (A-II).
ÎIf a patient appears clinically toxic or is severely immunocompromised, blood cultures may be helpful in determining duration of antimicrobial therapy (B-III).
ÎSusceptibility testing for Pseudomonas, Proteus, Acinetobacter, Staphylococcus aureus, and predominant (up to two) Enterobacteriaceae should be performed, as these are more likely to yield resistant organisms (A-III).
ÎIf there is significant resistance (greater than 10-20%) of a common community isolate (eg, E. coli) to an antimicrobial regimen in widespread local use, routine culture and susceptibility studies should be obtained for perforated appendicitis and other community-acquired intra-abdominal infections (B-III).
