From the Research
Cephalexin is not effective against Pseudomonas aeruginosa. As a first-generation cephalosporin antibiotic, cephalexin lacks the necessary spectrum of activity to combat this particular gram-negative bacterium. Pseudomonas aeruginosa is naturally resistant to cephalexin due to several intrinsic resistance mechanisms, including low outer membrane permeability, efflux pumps that expel the antibiotic, and production of beta-lactamase enzymes that can inactivate the drug.
For Pseudomonas infections, more appropriate antibiotic choices would include antipseudomonal agents such as certain third and fourth-generation cephalosporins (ceftazidime, cefepime), carbapenems (meropenem), fluoroquinolones (ciprofloxacin), aminoglycosides (tobramycin), or piperacillin-tazobactam 1. Treatment of Pseudomonas infections often requires combination therapy and should be guided by susceptibility testing due to the bacterium's ability to develop resistance rapidly.
Some key points to consider when treating Pseudomonas infections include:
- The use of combination therapy to prevent the development of resistance 2, 3
- The importance of susceptibility testing to guide antibiotic selection 1
- The potential for resistance to develop with certain antibiotics, such as carbapenems 4
- The need for careful consideration of the patient's individual needs and risk factors when selecting an antibiotic regimen.
Overall, cephalexin is not a suitable choice for treating Pseudomonas aeruginosa infections, and alternative antibiotics with antipseudomonal activity should be used instead.