What are bacteria?

From the Guidelines

Bacteria are a major cause of intra-abdominal infections, and their management requires careful consideration of antibiotic resistance patterns and local epidemiology. The most recent and highest quality study on this topic is the 2017 WSES guidelines for management of intra-abdominal infections 1. According to this study, the major pathogens involved in community-acquired intra-abdominal infections are usual residents of gastrointestinal flora, including Enterobacteriaceae, streptococci, and certain anaerobes (particularly Bacteroides fragilis).

Key Points to Consider

• The choice of empiric antibiotic regimens in patients with intra-abdominal infections should be based on the clinical condition of the patients, the individual risk for infection by resistant pathogens, and the local resistance epidemiology 1.
• For patients with community-acquired intra-abdominal infections, agents with a narrower spectrum of activity are preferred, while for patients with healthcare-associated infections, antibiotic regimens with broader spectra of activity are preferred 1.
• The use of carbapenems should be limited to preserve the activity of this class of antibiotics, due to the concern of emerging carbapenem-resistance 1.
• New antibiotics such as ceftolozone/tazobactam and ceftazidime/avibactam have been approved for treatment of complicated intra-abdominal infections, including infections by ESBL-producing Enterobacteriaceae and P. aeruginosa 1.

Management of Intra-Abdominal Infections

• Initial antibiotic therapy for intra-abdominal infections is typically empirical in nature, and selection of appropriate empiric antibiotic therapy is critical for preventing unnecessary morbidity and mortality 1.
• In patients with uncomplicated intra-abdominal infections, post-operative antibiotic therapy is not necessary if source control is adequate 1.
• In patients with complicated intra-abdominal infections undergoing an adequate source-control procedure, a short course of antibiotic therapy (3-5 days) is recommended 1.
• Patients who have ongoing signs of peritonitis or systemic illness beyond 5-7 days of antibiotic treatment normally warrant a diagnostic investigation to determine whether additional surgical intervention is necessary 1.

Antibiotic Resistance

• Antimicrobial resistance has become a global threat to public health systems, and the emergence of multidrug-resistant organisms is a serious concern 1.
• The use of broad-spectrum antibiotics can contribute to the development of antibiotic resistance, and a rational and appropriate use of antibiotics is essential to reduce selection pressure on resistant pathogens 1.
• Local susceptibility patterns should be monitored, and antibiotic regimens should be adjusted accordingly to ensure effective treatment and minimize the risk of resistance development 1.

From the Research

Bacteria Overview

• Bacteria are microorganisms that can cause various types of infections, including urinary tract infections (UTIs) and sepsis 2, 3, 4, 5, 6
• The most frequent cause of upper urinary tract infection is E. coli, but other organisms can also be responsible, especially in complicated infections 4

Treatment of Bacterial Infections

• Rapid initiation of antibiotic treatment is crucial in patients with severe infections such as septic shock and bacterial meningitis 2
• For patients presenting with suspected bacterial infections, withholding antibiotic therapy until diagnostic results are available and a diagnosis has been established seems acceptable in most cases unless septic shock or bacterial meningitis are suspected 2
• Treatment options for UTIs include nitrofurantoin, fosfomycin, pivmecillinam, fluoroquinolones, and beta-lactams such as amoxicillin-clavulanate 3
• Parenteral treatment options for UTIs due to ESBLs-producing Enterobacteriales include piperacillin-tazobactam, carbapenems, and ceftazidime-avibactam 3

Antibiotic Resistance

• Antibiotic-resistant Gram-negative bacteria are a growing concern due to limited treatment options 3
• High rates of resistance for trimethoprim-sulfamethoxazole and ciprofloxacin preclude their use as empiric treatment of UTIs in several communities 3
• The use of new antimicrobials should be done wisely to avoid resistance development 3

Specific Antibiotics

• Trimethoprim has antimicrobial activity by blocking the reduction of dihydrofolate to tetrahydrofolate, and is effective therapy for women with acute symptomatic urinary tract infections caused by E. coli 6
• Ceftriaxone is a long-acting, third-generation cephalosporin that can be used as a single-dose treatment for urinary tract infections 5