Carbapenems
Carbapenems are structurally related to penicillins and have broad-spectrum bactericidal activity. The carbapenems exert their effect by inhibiting cell wall synthesis, which leads to cell death. They are active against gram-negative bacteria, gram-bacteria, and anaerobes.
Meropenem (Merrem IV)
A bactericidal broad-spectrum carbapenem antibiotic that inhibits cell-wall synthesis, meropenem is effective against most gram-positive and gram-negative bacteria. Compared with imipenem, meropenem has slightly increased activity against gram-negative organisms and slightly decreased activity against staphylococci and streptococci.
Aztreonam (Azactam)
Aztreonam is a monobactam, not a beta-lactam, antibiotic that inhibits cell wall synthesis during bacterial growth. It is active against gram-negative bacilli but has very limited gram-positive activity and is not useful for anaerobes. Aztreonam lacks cross-sensitivity with beta-lactam antibiotics. It may be used in patients allergic to penicillins or cephalosporins. Transient or persistent renal insufficiency may prolong serum levels.
Ertapenem (Invanz)
The bactericidal activity of ertapenem results from inhibition of cell wall synthesis and is mediated through binding to penicillin-binding proteins. Ertapenem is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, cephalosporinases, and extended spectrum beta-lactamases; it is hydrolyzed by metallo-beta-lactamases.
Imipenem and cilastatin (Primaxin)
This combination is used for treatment of infections with multiple organisms because other agents do not have wide spectrum coverage or are contraindicated due to potential for toxicity.
Imipenem/cilastatin/relebactam (Recarbrio)
Three-drug combination containing previously approved imipenem/cilastatin and relebactam, a beta-lactamase inhibitor. It is indicated for complicated urinary tract infections, including pyelonephritis, and complicated intra-abdominal infections in adults with limited or no other treatment options. Dosage modifications are necessary for patients who have renal impairment.
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Peritonitis and abdominal sepsis. Diagnostic and therapeutic approach to peritonitis and peritoneal abscess.
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Peritonitis and abdominal sepsis. A 48-year-old man underwent suprapubic laparotomy, right hemicolectomy, and gastroduodenal resection for right colon cancer invading the first portion of the duodenum. After surgery, the patient developed abdominal pain and distention. Computed tomography (CT) scanning was used to confirm an anastomotic dehiscence. Figure A shows a contrast-enhanced scan of the abdomen and pelvis that reveals multiple fluid collections, perihepatic ascites, and mild periportal edema. A collection of fluid containing an air-fluid level is visible anterior to the left lobe of the liver. A second collection is anterior to the splenic flexure of the colon. In figure B, a third fluid collection is present in the inferior aspect of the lesser space and in the transverse mesocolon. Figure C shows the pelvis with a collection of free fluid in the rectovesical pouch.
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Peritonitis and abdominal sepsis. A 78-year-old man was admitted with a history of prior surgery for small bowel obstruction and worsening abdominal pain, distended abdomen, nausea, and obstipation. In figure A, a marked amount of portal venous gas within the liver, mesenteric venous gas, and pneumatosis intestinalis are consistent with ischemic small intestine. The superior mesenteric artery appears patent. The liver has a nodular contour consistent with cirrhosis. In figures B and C, markedly distended loops of small intestine containing fluid and air-fluid levels are consistent with a small bowel obstruction. No focal fluid collections are identified.
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Peritonitis and abdominal sepsis. A 35-year-old man with a history of Crohn disease presented with pain and swelling in the right abdomen. In figure A, a thickened loop of terminal ileum is evident adherent to the right anterior abdominal wall. In figure B, the right anterior abdominal wall is markedly thickened and edematous, with adjacent inflamed terminal ileum. In figure C, a right lower quadrant abdominal wall abscess and enteric fistula are observed and confirmed by the presence of enteral contrast in the abdominal wall.
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Peritonitis and abdominal sepsis. Gram-negative Escherichia coli.
