What is the treatment for Serratia marcescens infection?

From the Guidelines

Meropenem is the recommended treatment for Serratia marcescens infections, particularly for meningitis caused by gram-negative bacilli that produce extended-spectrum b-lactamases or those that may hyperproduce lactamases, such as Serratia marcescens, due to its broad range of in vitro activity and less seizure proclivity compared to imipenem 1.

Treatment Options

• Meropenem (1g IV every 8 hours) is a suitable choice for treating Serratia marcescens infections, especially in cases of meningitis, as it has been shown to have clinical and microbiologic outcomes similar to those of cefotaxime or ceftriaxone 1.
• Imipenem (500mg IV every 6 hours) can also be used, but its potential for seizure activity argues against its use in most patients with bacterial meningitis 1.
• Other alternatives, such as fluoroquinolones, third-generation cephalosporins, or aminoglycosides, may be considered, but meropenem is generally preferred due to its efficacy and safety profile.

Important Considerations

• Susceptibility testing is crucial to guide appropriate therapy, as Serratia marcescens is naturally resistant to several antibiotics, including ampicillin, amoxicillin, and first-generation cephalosporins.
• Combination therapy may be necessary for severe infections, particularly in immunocompromised patients or those with bacteremia.
• Source control through drainage of abscesses or removal of infected devices is essential when applicable.
• Treatment duration varies based on infection site, with urinary tract infections requiring 7-10 days, pneumonia 7-14 days, and bloodstream infections or endocarditis needing 2-6 weeks of therapy.

From the FDA Drug Label

AVYCAZ (ceftazidime and avibactam) is indicated for the treatment of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP) in adult and pediatric patients (at least 31 weeks gestational age) caused by the following susceptible gram-negative microorganisms: Klebsiella pneumoniae, Enterobacter cloacae, Escherichia coli, Serratia marcescens, Proteus mirabilis, Pseudomonas aeruginosa, and Haemophilus influenzae.

The treatment for Serratia marcescens is AVYCAZ (ceftazidime and avibactam), which is indicated for the treatment of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP) caused by Serratia marcescens 2.

• The recommended dosage of AVYCAZ is 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) administered every 8 hours by intravenous (IV) infusion over 2 hours in patients 18 years of age and older with CrCl greater than 50 mL/min.
• The duration of treatment is 7 to 14 days for HABP/VABP.

From the Research

Treatment Options for Serratia marcescens Infections

• The treatment of Serratia marcescens infections should include carbapenems or aminoglycosides in combination with third-generation (and eventually fourth-generation) cephalosporin 3.
• Cotrimoxazole should be considered in cases of uncomplicated urinary infections 3.
• Cefotaxime and gentamicin are suitable antibiotics for treatment, with low resistance rates of 0.6% 4.
• Meropenem-vaborbactam may be a potential option for severe SME-producing infections 5.
• High-dose meropenem can be effective in treating multiresistant Serratia marcescens infections, especially in the elderly 6.

Antibiotic Susceptibility

• Serratia marcescens isolates have shown increased susceptibility to ampicillin + sulbactam, cefotaxime, chloramphenicol, doxycycline, fosfomycin, gentamicin, piperacillin, piperacillin + tazobactam, timentin, and tobramycin over a 20-year observation period 7.
• However, there has been a decrease in susceptibility to ciprofloxacin, nalidixic acid, and trovafloxacin, and slightly diminished susceptibility to norfloxacin and ofloxacin 7.
• Serratia liquefaciens isolates have shown increased susceptibility to ampicillin, ampicillin + sulbactam, cefuroxime, doxycycline, fosfomycin, nitrofurantoin, and polymyxin B 7.

Resistance Patterns

• Serratia marcescens isolates are resistant to a wide range of antibiotics, including penicillin, cephalosporin, tetracycline, macrolide, nitrofurantoin, and colistin 3.
• Clinical isolates of Serratia have exhibited high resistance to ceftriaxone, ceftazidime, and piperacillin/tazobactam 4.
• SME-producing Serratia marcescens isolates are resistant to imipenem, imipenem-relebactam, and meropenem, but susceptible to ceftazidime, ceftazidime-avibactam, and meropenem-vaborbactam 5.