What Is Antibiotic Therapy for Peritonitis?
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Antibiotic Therapy for Peritonitis - An Overview

Published on Jan 23, 2023 and last reviewed on Jun 13, 2023   -  4 min read


Antibiotic therapy for peritonitis is based on the susceptibility of bacteria. Read in detail the below article to know more about the combination used.


Infection is caused by a microorganism, and inflammation occurs as one of the responses to the infection or the organisms. However, in most cases, inflammation is a stereotyped response; it depends on the mechanisms of adaptive immunity and innate immunity, especially with each pathogen.

Antibiotics are the medications provided in cases of bacterial infections in humans, and they are ineffective against any viral infections. In most cases, the initial line of treatment for severe infections and inflammations antibiotics are prescribed to treat the condition. They work by destroying the bacteria and preventing them from spreading and reproducing. A wide range of combinations is available accordingly that can lead to the treatment. It is a widely used treatment of choice in cases of peritoneal inflammation.

What Is Peritonitis?

Peritonitis is an inflammation of the peritoneum that can occur by non-pathogenic or pathogenic factors. In such conditions, there are always three terms: contamination, infection, and sepsis. Contamination is related to the presence of bacteria, infection means inflammation due to the presence of bacteria, and sepsis means response to local infection. Peritonitis can be caused by anatomical dehiscence, translocation of germs, perforation of the bowel, inflammation, or perforation of a hollow viscus.

Peritonitis is classified into three types:

  • Primary Bacterial Peritonitis: Spontaneous bacterial invasion of the peritoneal cavity. It mainly affects infancy and early childhood.

  • Secondary Bacterial Peritonitis: Peritoneal infections secondary to intra-abdominal lesions, like perforation, nonbacterial peritonitis, and bowel necrosis.

  • Tertiary Bacterial Peritonitis: Persistent or recurrent infections with low intrinsic organisms. Usually needs operative attempts to treat secondary peritonitis.

Intra-abdominal infections are found in 25 % of individuals with multiple organ failure. Mortality of peritonitis is directly related to the severity of the disease.

What Are the Causes of Peritonitis?

Infection to the peritoneum leads to peritonitis, and the condition can develop by peritoneum rupture. Common causes are a ruptured appendix, perforated colon, and stomach ulcer, allowing bacteria into the gastrointestinal tract.

  • Pancreatitis: Peritonitis can occur due to inflammation of the pancreas if the bacteria spread outside the pancreas.

  • Diverticulitis: These conditions lead to the formation of tiny bulging sacs or pouches in the digestive tract. When these pouches get inflamed and infected, diverticulitis occurs. This can also aggravate as a cause of peritonitis.

  • Medical Procedures: The tube switches used in peritoneal dialysis are inserted to remove waste products from the blood. The infection occurs during peritoneal dialysis due to unclean surroundings, poor hygiene, or contaminated equipment. This condition also develops as a complication of gastrointestinal surgery, and sometimes as a complication of colonoscopy or endoscopy.

  • Trauma: Trauma or injury that allows bacteria or chemicals to enter the peritoneum from other parts of the body.

  • Pelvic Inflammatory Diseases in Women: These are sexually transmitted infections of the upper reproductive organs, involving the ovaries, fallopian tubes, and uterus.

What Are the Signs and Symptoms of Peritonitis?

Signs and symptoms are:

  • Fever.

  • Nausea.

  • Vomiting.

  • Abdominal pain or tenderness.

  • Bloating or feeling of fullness.

  • Loss of appetite.

  • Confusion.

  • Fatigue.

  • Inability to pass stool.

  • Diarrhea.

  • Thirst.

  • Low urine output.

How Is the Diagnosis for Peritonitis Done?

Diagnosis of peritonitis is based on clinical signs revealed and other tests like:

  • Chest and Abdominal X-ray: Imaging techniques are used to view body tissues, especially bones.

  • CT Scan: Diagnostic imaging technique that combines computer technology and X-rays to produce body images.

  • Ultrasound: The imaging technique helps to detect any kind of perforations in the abdominal cavity.

  • Urine Tests, or Fluid Analysis: In a few cases, the abdomen is built up with fluid. Using a needle, some fluid is drained and given for analysis. This culturing of the fluids helps in identifying the bacteria responsible.

  • Blood Tests: A complete blood analysis is done, and white blood cells (WBCs) and red blood cells (RBCs) are calculated. A high WBC count reveals signs of infection and inflammation, while a low RBC count reveals intra-abdominal bleeding. A blood culture helps to identify the infection-causing bacteria.

What Is the Treatment Done for Peritonitis?

Treatment of peritonitis depends on treating the infection caused by other medical conditions:

  • Antibiotics: A course of antibiotics is given orally or intravenously to fight the infection and reduce its capacity to spread. The type and duration of the antibiotics given depend upon the severity of the condition.

  • Surgery: Surgery is often required to remove an infected part of the tissue. This would treat the underlying cause of the infection and prevent the disease from spreading, especially in case of a ruptured stomach, colon, or appendix.

  • Other Treatments: Other treatments depend on signs and symptoms. It includes pain medications, administration of intravenous fluids, oxygen even blood transfusion in some cases.

What Is Antibiotic Therapy for Peritonitis?

  • Antibiotic therapy is commonly used in cases of infection and sepsis, and they are sufficient in eliminating pathogens causing surgical sepsis. Regimens with less or no gram-negative activity rods or anaerobic gram-negative are not considered.

  • The acceptable regimens are newer Quinolones and Carbapems, or a combination of both, for example, Imipenem-Cilastatin. Also, anti-anaerobic third-generation Cephalosporins or Quinolones, and anti-anaerobes plus aminoglycosides or Clindamycin with Monobactam are recommended for treating peritonitis.

  • Mild to moderate community-acquired infections are treated with Cefmetazole, Ticarcillin-Clavulanic acid, Cefoxitin, and Cefotetan.

  • Routine culture tests and empirical therapy should also be given to cover all possible pathogens possibly.

  • Antibiotic therapy is usually recommended for five to seven days in generalized peritonitis. The recommended duration of antimicrobial therapy in postoperative peritonitis should be no longer than seven days.

  • Peritoneal dialysis patients often experience peritonitis at the time of catheter insertion and removal, antibiotics are typically administered to fight these acute infections, and an initial antibiotic dose is recommended at the time of catheter placement to prevent subsequent infections.

  • Antimicrobial therapy duration should be given until white blood cells and temperature are within normal limits. Persistent monitoring of fever and leukocytosis should be prompt for the drainable focus of infection in the abdomen.


In most cases of peritonitis, antibiotic therapy gives symptomatic relief. Due to the underlying bacterial contamination, surgery combined with lavage with a course of antibiotics is recommended. Tertiary peritonitis is often attributed to antibiotic-resistant bacteria that are not affected by the first line of antibiotics. In such cases, stronger-acting antibiotics are used for treatment, and individuals may have to undergo laparoscopy for proper diagnosis of the root cause of the infection.

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Last reviewed at:
13 Jun 2023  -  4 min read




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