Appropriate Antimicrobial Regimen Initial Antimicrobial Therapy For Suspected or Co Community Acquired: Adult Microbiology
> Antibiotics used for empiric treatment of community-acquired intra-abdominal infections should be active against enteric gram-negative aerobic and facultative bacilli and enteric gram-positive streptococci (A-I).
> Coverage for obligate anaerobic bacilli should be provided for distal small bowel, appendiceal and colon-derived infections, and for more proximal gastrointestinal perforations in the presence of obstruction or paralytic ileus (A-I).
Recommended empiric regimens (while awaiting pathogen identity and susceptibilities) Mild-to-Moderate Severity1,2
Cefoxitin, ertapenem3 tigecycline5
, moxifloxacin4
and combinations of cefazolin, cefuroxime, ceftriaxone, cefotaxime, levofloxacin4
, or ciprofloxacin4
with metronidazole—are preferable to regimens with substantial anti- pseudomonal activity (A-I).
, , and ticarcillin/clavulanate; —each High Severity (APACHE II scores > 15)
> Meropenem; imipenem/cilastatin; doripenem; piperacillin/tazobactam; ciprofloxacin4
or levofloxacin4 , either
> Aztreonam plus metronidazole is an alternative (B-III).
in combination with metronidazole; ceftazidime or cefepime plus metronidazole (A-I).
> Addition of an agent effective against gram-positive cocci, such as vancomycin, is recommended (B-III).
Agents effective against enterococci are recommended (B-II).
If 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).
1• Because of the availability of less toxic agents demonstrated to be of at least equal efficacy, aminoglycosides are not recommended (B-II).
• Empiric coverage of Enterococcus is not necessary in patients with community-acquired intra-abdominal infections (A-I).
• Ampicillin/sulbactam is not recommended because of high resistance of E. coli to this agent (B-II). • Cefotetan and clindamycin are not recommended for use because of increasing resistance of the Bacteroides fragilis group to these agents (B-II).
2• For those patients with mild-to-moderate severity intra-abdominal disease processes including acute diverticulitis and various forms of appendicitis who will not undergo a source control procedure, these regimens are recommended, with a possibility of early oral therapy (B-III).
• Empiric antifungal therapy for Candida is not recommended for adult and pediatric patients with community- acquired intra-abdominal infections (B-II).
