Intraabdominal infections treatment

Describe the role of culture and susceptibility information for diagnosis and treatment of intraabdominal infections. 

Cultures of secondary intraabdominal infection sites generally are not useful for directing antimicrobial therapy. Treatment generally is initiated on a presumptive or empirical basis. 

The duration of antimicrobial treatment should be for a total of 5 to 7 days for most intraabdominal infections. 

The treatment of intraabdominal infection most often requires the coordinated use of three major modalities (1) prompt drainage, (2) support of vital functions, and (3) appropriate antimicrobial therapy to treat infection not eradicated by surgery. Antimicrobials are an important adjunct to drainage procedures in the treatment of secondary intraabdominal infections however, the use of antimicrobial agents without surgical intervention usually is inadequate. For most cases of primary peritonitis, drainage procedures may not be required, and antimicrobial agents become the mainstay of therapy. 

Many studies have been conducted evaluating or comparing the effectiveness of antimicrobials for treatment of intraabdominal infections. Substantial differences in patient outcomes from treatment with a variety of agents generally have not been demonstrated. 

Five to seven days of antimicrobial treatment are sufficient for most intraabdominal infections of mild to moderate severity. 

Intraabdominal infection presents in many different ways and with a wide spectrum of severity. The antibiotic regimen employed and duration of treatment depend on the specific clinical circumstances (i.e., the nature of the underlying disease process and the condition of the patient). 

Table 74—2 presents the recommended agents for treatment of community-acquired and complicated intraabdominal infections from the Infectious Diseases Society of America and the Surgical Infection Society.21-23 These recommendations were formulated using an evidence-based approach. Most community-acquired infections are mild to moderate, whereas health care-associated infections tend to be more severe and difficult to treat. Table 74-3 presents guidelines for treatment and alternative regimens for specific situations. These are general guidelines there are many factors that cannot be incorporated into such a table. 

TABLE 74-2. Recommended Agents for the Treatment of Community-Acquired Complicated Intraabdominal Infections... 

Treatment regimens for intraabdominal infection can be judged as successful if the patient recovers from the infection without recurrent peritonitis or intraabdominal abscess and without the need for additional antimicrobials. A regimen can be considered unsuccessful if a significant adverse drug reaction occurs, reoperation or percutaneous drainage is necessary, or patient improvement is delayed beyond 1 or 2 weeks. 

Enterococcus species are normal inhabitants of the gastrointestinal tract, but should empiric treatment of intra-abdominal infections have activity against Enterococcus species Empiric treatment that covered Enterococcus species in intraabdominal infections was equivalent to empiric treatment that lacked enterococcal coverage. Routine coverage for Enterococcus is not necessary for patients with community-acquired intra-abdominal infections. However, in patients with nosocomial or high-severity infections, enterococcal coverage may be warranted.39... 

The overall outcome from intraabdominal infection depends on five key factors inoculum size, virulence of the organisms, the presence of adjuvants within the peritoneal cavity that facilitate infection, the adequacy of host defenses, and the adequacy of initial treatment. 

The three major modalities for the treatment of intraabdominal infection are prompt surgical drainage, support of vital functions, and appropriate antimicrobial therapy to treat infection not removed by surgery. 

Antimicrobials are an important adjunct to drainage procedures in the treatment of intraabdominal infections however, the use of antimicrobial agents without surgical intervention is usually inadequate. For some specific situations (e.g., most cases of primary peritonitis), drainage procedures... 

Evidence-based treatment principles for complicated intraabdominal infections are given in Table 42-6. 

Antibiotics used for empirical treatment of community-acquired intraabdominal infections should be active against empiric gram-negative aerobic and facultative bacilli and /5-lactam-susceptible gram-positive cocci. 

Dosage The recommended dosage regimen for tigecycline is an initial dose of 100 mg, followed by 50 mg every 12 hours. Intravenous (IV) infusions of tigecycline should be administered over approximately 30 to 60 minutes every 12 hours. Treatment duration The recommended duration of treatment with tigecycline for complicated skin and skin structure infections or for complicated intraabdominal infections is 5 to 14 days. 

The third-generation cephalosporins are effective in the treatment of bacteremias, pneumonias, urinary tract infections, intraabdominal infections, and skin and soft tissue infections. 

The indications for penicillin-B-lactamase inhibitor combinations are empirical therapy for infections caused by a wide range of potential pathogens in both immunocompromised and immunocompetent patients and treatment of mixed aerobic and anaerobic infections, such as intraabdominal infections. Doses are the same as those used for the single agents except that the recommended dosage of piperacillin in the piperacillin-tazobactam combination is 3 g every 6 hours. This is less than the recommended 3-4 g every 4-6 hours for piperacillin alone, raising concerns about the use of the combination for treatment of suspected pseudomonal infection. Adjustments for renal insufficiency are made based on the penicillin component. 

Combination therapy is often used when dealing with infections caused by both aerobic and anaerobic bacteria [50,80]. Combination of metronidazole with either gentamicin or ciprofloxacin appeared to be effective in preventing infection of abdominal trauma [101] when combined with ciprofloxacin, metronidazole was affective as a preoperative antibiotic in colorectal surgery and appeared equal in efficacy to impipenem/cilastin for the treatment of complicated intraabdominal infections [103]. Combination therapy is not always indicated for the treatment of polymicrobial infections. New antibiotics, whose spectrum includes multiple classes of microorganisms (e.g., imipenem), may often preclude combination therapy. 

Antimicrobial regimens for secondary intraabdominal infections should include coverage for enteric gram-negative bacilli and anaerobes. Antimicrobials that may be used for the treatment of secondary intraabdominal infections include (a) a /3-lactam// -lactamase inhibitor combination, (b) a carbapenem, (c) quinolone plus metronidazole, or an aminoglycoside plus clindamycin (or metronidazole). 

Aggressive fluid repletion and management are required for successful treatment of intraabdominal infections. Fluid therapy is instituted for the purposes of achieving or maintaining proper intravascular volume to ensure adequate cardiac output, tissue perfusion, and correction of acidosis. Loss of fluid through vomiting, diarrhea, or a nasogastric suction contributes to dehydration. Intravascular volume can be assessed by blood pressure and heart rate but more accurately... 

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