Change Antibiotic Immediately - Clindamycin Does Not Cover Enterobacter cloacae
Clindamycin has no activity against Enterobacter cloacae and must be changed to an agent with documented susceptibility, such as ciprofloxacin, gentamicin, meropenem, or sulfamethoxazole-trimethoprim. 1
Why Clindamycin Fails for This Infection
Clindamycin's spectrum is limited to gram-positive cocci (including S. aureus and streptococci) and anaerobes - it has no meaningful activity against gram-negative rods like Enterobacter species 1
The guidelines explicitly state that gentamicin or fluoroquinolones are required for coverage of resistant gram-negative rods, while clindamycin covers only anaerobes and aerobic gram-positive cocci 1
Enterobacter cloacae is an aerobic gram-negative bacillus from the Enterobacteriaceae family that requires agents specifically active against gram-negative organisms 2, 3
Recommended Antibiotic Switch Based on Susceptibilities
Switch to one of the following susceptible agents:
Ciprofloxacin (or levofloxacin): Excellent oral bioavailability allows transition to outpatient therapy for uncomplicated wound infections 1, 2
Sulfamethoxazole-trimethoprim: Reasonable option for susceptible isolates, though resistance rates in Enterobacteriaceae can reach 13-16% 2
Gentamicin: Effective but requires monitoring of renal function and drug levels; generally reserved for more severe infections 1, 2
Meropenem: Most definitive coverage but reserve for severe infections or when other options are contraindicated, as carbapenems should be preserved to prevent resistance 1, 3
Clinical Decision Algorithm
For uncomplicated wound infection/cellulitis:
- Switch to oral ciprofloxacin 500-750 mg twice daily if patient is clinically stable and can tolerate oral therapy 1
- Alternative: sulfamethoxazole-trimethoprim DS twice daily 1
For severe infection with systemic toxicity:
- Use IV ciprofloxacin 400 mg every 12 hours or meropenem 1 g every 8 hours 1
- Consider gentamicin with appropriate monitoring 1
Critical Pitfalls to Avoid
Do not continue clindamycin - there is zero activity against Enterobacter species, and continuing ineffective therapy risks treatment failure and progression of infection 1
Avoid cephalosporins - Enterobacter cloacae characteristically develops resistance to third-generation cephalosporins through AmpC β-lactamase overproduction during therapy, and your isolate is already resistant to cefazolin 3, 4
Check local fluoroquinolone resistance patterns - resistance in Enterobacter cloacae to fluoroquinolones has been increasing (from 94% susceptibility in 1998 to 89% in 2001), though your isolate is documented as susceptible 2
Ampicillin-sulbactam is not an option despite the sulbactam component, as Enterobacter species have high intrinsic resistance rates (only 45-57% susceptibility) 2