From the Research
Doxycycline does not effectively cover Proteus mirabilis infections. Proteus mirabilis is naturally resistant to doxycycline and other tetracycline antibiotics, as shown in a study from 1, which found that the highest susceptibility levels were observed for piperacillin-tazobactam, carbapenems, and cephalosporins antibiotics, but not for tetracyclines. This resistance occurs because Proteus species have efflux pumps that actively remove tetracyclines from bacterial cells, preventing the antibiotic from reaching effective concentrations inside the bacteria. For Proteus mirabilis infections, more appropriate antibiotic choices include:
- Trimethoprim-sulfamethoxazole
- Fluoroquinolones (such as ciprofloxacin)
- Third-generation cephalosporins
- Aminoglycosides
- Carbapenems, depending on the site and severity of infection and local resistance patterns, as suggested by 1 and 2. When treating a suspected or confirmed Proteus infection, it's essential to obtain culture and sensitivity testing to guide appropriate antibiotic selection, as resistance patterns can vary, as noted in 3 and 2. Proteus species are common causes of urinary tract infections, particularly in patients with urinary catheters or structural abnormalities, and can also cause wound infections and septicemia, as reported in 1 and 4.