What are the inpatient antibiotic options for Proteus (Proteus) infections?

From the Guidelines

For inpatient treatment of Proteus infections, a combination of a penicillin, such as ampicillin (2 g IV every 4 hours), or a broad-spectrum cephalosporin with an aminoglycoside, usually gentamicin (1.7 mg/kg every 8 hours), is recommended. This approach is based on the guidelines for the treatment of infective endocarditis caused by Gram-negative bacilli, including Proteus mirabilis, as outlined in the statement from the American Heart Association 1.

When considering the treatment of Proteus infections, it is essential to note that these bacteria are gram-negative and can cause a range of infections, including urinary tract infections, wound infections, and bacteremia. The choice of antibiotic should be guided by culture and sensitivity results when available, and doses should be adjusted for renal function.

Some key points to consider in the treatment of Proteus infections include:

• The use of third-generation cephalosporins, which have been shown to be effective against E coli in vitro and may be effective against Proteus species as well 1.
• The potential for certain -lactam/-lactamase inhibitor combinations, such as piperacillin-tazobactam, to be active against Proteus species, although this may require further evaluation in combination with an aminoglycoside 1.
• The importance of determining the minimum bactericidal concentration (MBC) to guide therapy, as the specific aminoglycoside used can be a critical variable 1.

Overall, the treatment of Proteus infections requires careful consideration of the antibiotic susceptibility patterns of the specific strain, as well as the severity and site of the infection. A combination of a penicillin or broad-spectrum cephalosporin with an aminoglycoside is a reasonable initial approach, with adjustments made based on culture and sensitivity results and clinical response 1.

From the FDA Drug Label

1 INDICATIONS AND USAGE

1.5 Skin and Skin Structure Infections Tobramycin for Injection is indicated for the treatment of skin and skin structure infections caused by susceptible isolates of P. aeruginosa, Proteus spp., E. coli, Klebsiella spp., Enterobacter spp., and S. aureus in adult and pediatric patients.

1. 6 Bone Infections Tobramycin for Injection is indicated for the treatment of bone infections caused by susceptible isolates of P. aeruginosa, Proteus spp., E. coli, Klebsiella spp., Enterobacter spp., and S. aureus in adult and pediatric patients

2. 7 Complicated and Recurrent Urinary Tract Infections Tobramycin for Injection is indicated for the treatment of complicated urinary tract infections caused by susceptible isolates of P. aeruginosa, Proteus spp., (indole-positive and indole-negative), E. coli, Klebsiella spp., Enterobacter spp., Serratia spp., S. aureus, Providencia spp., and Citrobacter spp. in adult and pediatric patients

Tobramycin can be used as an inpatient antibiotic for the treatment of Proteus infections, specifically for:

• Skin and skin structure infections caused by susceptible isolates of Proteus spp.
• Bone infections caused by susceptible isolates of Proteus spp.
• Complicated and recurrent urinary tract infections caused by susceptible isolates of Proteus spp. (indole-positive and indole-negative) 2

From the Research

Inpatient Antibiotics for Proteus

• The choice of antibiotic for treating Proteus infections depends on various factors, including the severity of the infection, the patient's medical history, and the susceptibility of the bacteria to different antibiotics 3, 4, 5.
• Meropenem, a broad-spectrum carbapenem antibiotic, has been shown to be effective against Proteus mirabilis, with a low minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) 4.
• However, the susceptibility of Proteus mirabilis to different antibiotics can vary, and resistance to certain antibiotics, such as cefotaxime and ceftazidime, has been reported 5.
• Other antibiotics, such as cefepime, piperacillin/tazobactam, and fluoroquinolones, may also be effective against Proteus mirabilis, but their use may be limited by resistance or other factors 6.
• In cases of carbapenem-resistant Gram-negative bacterial infections, including those caused by Proteus mirabilis, newer agents such as ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol may be effective treatment options 7.

Antibiotic Resistance

• The increasing prevalence of antibiotic resistance among Gram-negative bacteria, including Proteus mirabilis, is a major concern, and the use of broad-spectrum antibiotics should be carefully considered to minimize the risk of resistance development 5, 7.
• The revised Clinical and Laboratory Standards Institute (CLSI) breakpoints for certain antibiotics, such as cefazolin and imipenem, can significantly impact the reported susceptibility rates of Proteus mirabilis 5.

Treatment Considerations

• The treatment of Proteus infections should be guided by susceptibility testing and clinical experience, and the choice of antibiotic should be based on the severity of the infection, the patient's medical history, and the potential for resistance development 3, 4, 5.
• Antimicrobial stewardship is crucial in ensuring the appropriate and rational use of antibiotics, particularly in cases of carbapenem-resistant Gram-negative bacterial infections 7.