Serratia Medication

Updated: Oct 25, 2021
  • Author: Payal K Patel, MD, MPH; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication Summary

S marcescens is naturally resistant to ampicillin, macrolides, and first-generation cephalosporins. In Taiwan, 92% of the strains are resistant to cefotaxime, but 99% are still susceptible to ceftazidime. Extended spectrum beta-lactamases are produced by most S marcescens strains. [35] International data on antimicrobial susceptibility of Serratia and other nosocomial isolates have been published. [36, 37]

Serratia infections should be treated with an aminoglycoside plus an antipseudomonal beta-lactam, as the single use of a beta-lactam can select for resistant strains. Most strains are susceptible to amikacin, but reports indicate increasing resistance to gentamicin and tobramycin. Quinolones also are highly active against most strains.

Cefepime or broad-spectrum beta-lactam/beta-lactamase inhibitor combinations may be a reasonable option for the treatment of infections with Serratia strains that produce AmpC beta-lactamase. [38, 39]  

Definitive therapy should be based on the results of susceptibility testing because multiresistant strains are common.



Class Summary

Empiric antimicrobial therapy should cover all likely pathogens in the context of the clinical setting.

Levofloxacin (Levaquin)

For pseudomonal infections and infections due to multidrug-resistant gram-negative organisms.

Cefepime (Maxipime)

Fourth-generation cephalosporin. Gram-negative coverage comparable to ceftazidime but has better gram-positive coverage (comparable to ceftriaxone). Cefepime is a zwitter ion; rapidly penetrates gram-negative cells. Best beta-lactam for IM administration. Poor capacity to cross blood-brain barrier precludes use for treatment of meningitis.

Ertapenem (Invanz)

Bactericidal activity results from inhibition of cell wall synthesis and is mediated through ertapenem binding to penicillin-binding proteins. Stable against hydrolysis by various beta-lactamases including penicillinases, cephalosporinases, and extended-spectrum beta-lactamases. Hydrolyzed by metallo-beta-lactamases.


Preferred aminoglycoside. Usually synergistic with antipseudomonal beta-lactams. Use both in combination, pending results of susceptibility testing. For gram-negative bacterial coverage of infections resistant to gentamicin and tobramycin. Effective against Pseudomonas aeruginosa. Irreversibly binds to 30S subunit of bacterial ribosomes. Blocks recognition step in protein synthesis. Causes bacterial growth inhibition.

Aztreonam (Azactam)

Usually synergistic with amikacin. Use both in combination, pending results of susceptibility testing. A monobactam that inhibits cell wall synthesis during bacterial growth. Active against gram-negative bacilli.

Meropenem (Merrem IV)

Preferred therapy for Serratia meningitis. Bactericidal broad-spectrum carbapenem antibiotic that inhibits cell wall synthesis. Effective against most gram-positive and gram-negative bacteria. Has increased activity against gram-negative bacteria and slightly decreased activity against staphylococci and streptococci compared to imipenem.

Imipenem-cilastatin (Primaxin)

Carbapenem is used for treatment of multiple-organism infections in which other agents do not have wide-spectrum therapeutic activity or are contraindicated because of potential toxicity. Comparable in activity to meropenem.

Ciprofloxacin (Cipro)

Greatest anti-P aeruginosa activity among the quinolones. May be particularly useful for isolates resistant to the aminoglycosides.

Ticarcillin/clavulanate (Timentin)

Inhibits biosynthesis of cell wall mucopeptide and is effective during stage of active growth. Antipseudomonal penicillin plus beta-lactamase inhibitor that provides coverage against most gram-positive organisms, most gram-negative organisms, and most anaerobes. Contains 4.7-5.0 mEq of Na+/g.

Piperacillin/tazobactam (Zosyn)

This drug combination consists of an antipseudomonal penicillin plus a beta-lactamase inhibitor. It inhibits the biosynthesis of cell wall mucopeptide and is effective during the active multiplication stage.

Ceftazidime/avibactam (Avycaz)

Ceftazidime/avibactam has shown showed potent in vitro activity when used against enterobacteriacae with inducible AmpC beta-lactamases, including Serratia marcescens.

Ceftolozane/tazobactam (Zerbaxa)

Inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins. This results in the inhibition of the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls, thus inhibiting cell wall biosynthesis.

Amoxicillin/clavulanate (Augmentin, Augmentin ES-600, Augmentin XR)

Amoxicillin is a third-generation aminopenicillin. Combined with the beta-lactam clavulanic acid, it is less susceptible to degradation by beta-lactamases produced by microorganisms. For children older than 3 months, base the dosing protocol on amoxicillin content. Because of different amoxicillin/clavulanic acid ratios in the 250-mg tablet (250/125) versus the 250-mg chewable tablet (250/62.5), do not use the 250-mg tablet until the child weighs more than 40 kg.

Trimethoprim/sulfamethoxazole (Bactrim, Bactrim DS, Cotrim)

TMP/SMX is a sulfonamide that synergistically kills bacteria by inhibiting tetrahydrofolic acid

Ceftriaxone (Rocephin)

As a third-generation cephalosporin, ceftriaxone should not be used if long treatment courses are required to prevent the development of inducable AmpC resistance.