What is a broad-spectrum antibiotic?

From the Guidelines

Broad spectrum antibiotics should be used judiciously in the treatment of intra-abdominal infections, with consideration of the patient's clinical condition, individual risk for infection by resistant pathogens, and local resistance epidemiology, as recommended by the 2017 WSES guidelines for management of intra-abdominal infections 1.

Key Considerations

• The choice of empiric antibiotic regimens should be based on the clinical condition of the patients, the individual risk for infection by resistant pathogens, and the local resistance epidemiology.
• In patients with community-acquired intra-abdominal infections (CA-IAIs), agents with a narrower spectrum of activity are preferred, while in patients with healthcare-associated infections (HA-IAIs), antibiotic regimens with broader spectra of activity are preferred.
• The use of broad-spectrum antibiotics such as carbapenems should be limited to preserve their activity against multidrug-resistant infections.

Antibiotic Options

• Beta-lactam/beta-lactamase inhibitor combinations, such as amoxicillin/clavulanate and piperacillin/tazobactam, have in vitro activity against gram-positive, gram-negative, and anaerobe organisms.
• Third-generation cephalosporins, such as cefotaxime and ceftriaxone, in association with metronidazole, may be options for the treatment of mild IAIs.
• Fluoroquinolones, such as ciprofloxacin and levofloxacin, are no longer appropriate as first-line treatment in many geographic regions due to the prevalence of fluoroquinolone resistance.
• New antibiotics, such as ceftolozone/tazobactam and ceftazidime/avibactam, have been approved for the treatment of complicated IAIs, including infections by ESBL-producing Enterobacteriaceae and P. aeruginosa.

Treatment Duration

• Treatment duration typically ranges from 5-14 days depending on the infection type and severity, with reassessment after 48-72 hours to evaluate clinical response and potentially de-escalate to narrower-spectrum agents.
• In patients with uncomplicated IAIs, such as uncomplicated appendicitis and uncomplicated cholecystitis, post-operative antibiotic therapy is not necessary if source control is adequate.
• In patients with complicated IAIs undergoing an adequate source-control procedure, a short course of antibiotic therapy (3-5 days) is recommended.

From the FDA Drug Label

Cefepime for injection, USP is a semi-synthetic, broad spectrum, cephalosporin antibiotic for parenteral administration. Ceftazidime is a semisynthetic, broad-spectrum, beta-lactam antibacterial drug for parenteral administration. The broad spectrum antibiotics mentioned are:

• Cefepime 2
• Ceftazidime 3
• Meropenem is also a broad spectrum antibiotic, but it is a carbapenem 4

From the Research

Broad Spectrum Antibiotic Characteristics

• Broad-spectrum antibiotics are used to treat a wide range of bacterial infections, including those caused by Gram-positive and Gram-negative pathogens 5, 6.
• Examples of broad-spectrum antibiotics include meropenem, a carbapenem with a broad spectrum of in vitro activity against Gram-positive and Gram-negative pathogens, including extended-spectrum beta-lactamase (ESBL)- and AmpC-producing Enterobacteriaceae 5.
• Other broad-spectrum antibiotics include ceftriaxone, piperacillin-tazobactam, and the carbapenems, which are commonly chosen for gram-negative infections 6.

Uses of Broad Spectrum Antibiotics

• Broad-spectrum antibiotics are often used as empirical therapy prior to the identification of causative organisms, or for disease caused by single or multiple susceptible bacteria in both adults and children with a broad range of serious infections 5.
• They are used to treat a variety of infections, including complicated intra-abdominal infection, complicated skin and skin structure infection, bacterial meningitis, nosocomial pneumonia, and severe community-acquired pneumonia 5, 6.
• Broad-spectrum antibiotics are also used to treat infections caused by multidrug-resistant organisms, such as MRSA and multidrug-resistant S pneumoniae 6.

Comparison of Broad Spectrum Antibiotics

• Meropenem has similar efficacy to comparator antibacterial agents, including imipenem/cilastatin, clindamycin plus tobramycin or gentamicin, and cefotaxime plus metronidazole 5.
• Cefepime has been shown to be effective against Enterobacteriaceae and gram-positive organisms, and has several advantages over older drugs, including a twice-a-day dosage schedule and enhanced activity against resistant organisms 7.
• The choice of broad-spectrum antibiotic depends on the specific infection being treated, as well as the patient's individual needs and medical history 8.