Will a regimen of metronidazole (Flagyl) / vancomycin (Vanco) / ciprofloxacin (Cipro) provide adequate coverage for a Prevotella species infection in a patient with a polymicrobial infected foot wound, also positive for Escherichia coli, Enterococcus, and Methicillin-resistant Staphylococcus aureus (MRSA)?

From the Guidelines

The current regimen of Flagyl (metronidazole), vancomycin, and ciprofloxacin is likely sufficient to cover Prevotella species, given metronidazole's efficacy against anaerobic bacteria, including Prevotella. The patient's infected foot wound tissue culture showing positivity for Prevotella species, E. coli, Enterococcus, and MRSA necessitates broad-spectrum antibiotic coverage.

• Metronidazole is effective against anaerobic bacteria, including Prevotella, which are commonly found in polymicrobial foot infections 1.
• Vancomycin provides coverage for MRSA, and ciprofloxacin addresses the E. coli.
• Enterococcus may be partially covered by vancomycin, though some enterococci can be resistant. Key considerations for the treatment regimen include:
• The IDSA guideline suggests various empiric antibiotic regimens based on infection severity, with metronidazole being an option for moderate to severe infections 1.
• The choice of antibiotics should be guided by the severity of the infection, the suspected pathogens, and local antimicrobial resistance patterns.
• Clinical improvement should be observed within 48-72 hours, and antibiotic susceptibility testing results should guide any necessary adjustments to the regimen.
• Adequate surgical debridement of the wound, if not already performed, is essential for successful treatment alongside antibiotic therapy. Given the available evidence, the current regimen appears to be a reasonable choice for empiric therapy in this case, covering the polymicrobial nature of the infection, including Prevotella species, as supported by the IDSA guideline for diabetic foot infections 1.

From the FDA Drug Label

Metronidazole has been shown to have in vitro and clinical activity against the following organisms: Anaerobic gram negative bacilli, including: Bacteroides species, including the Bacteroides fragilis group (B. fragilis, B. distasonis, B. ovatus, B. thetaiotaomicron, B vulgatus) Fusobacterium species Anaerobic gram negative bacilli, including: Metronidazole is active in vitro against most obligate anaerobes but does not appear to possess any clinically relevant activity against facultative anaerobes or obligate aerobes.

The regimen of flagyl (metronidazole) / vanco / cipro would likely cover Prevotella species, as Prevotella is an anaerobic gram-negative bacillus, which is similar to Bacteroides and Fusobacterium species that are susceptible to metronidazole 2.

From the Research

Antimicrobial Susceptibility of Prevotella Species

The patient's infected foot wound tissue culture is positive for Prevotella species, as well as E. coli, Enterococcus, and MRSA. The current regimen includes flagyl (metronidazole), vanco (vancomycin), and cipro (ciprofloxacin). To determine if this regimen covers Prevotella species, we need to examine the antimicrobial susceptibility of Prevotella species.

Susceptibility to Metronidazole

• According to the study 3, all Prevotella strains were susceptible to metronidazole, with only 2 (1.7%) isolates resistant to metronidazole.
• The study 4 also found that metronidazole showed activity against >99% of Prevotella strains.
• The study 5 confirmed that all Prevotella species were susceptible to metronidazole.
• The study 6 found that all 33 Prevotella strains were susceptible to metronidazole.
• The study 7 also found that all isolates were susceptible to metronidazole, with only four isolates resistant to metronidazole.

Coverage of Prevotella Species by the Current Regimen

• The current regimen includes metronidazole, which has been shown to be effective against Prevotella species in the studies 3, 4, 5, 6, and 7.
• Therefore, the current regimen is likely to cover Prevotella species, as metronidazole is a effective agent against these bacteria.
• However, it is essential to note that the susceptibility of Prevotella species to antimicrobials can vary depending on the species, geographic location, and other factors, as highlighted in the studies 3, 4, and 5.

Other Antimicrobial Agents

• The studies 3, 4, and 5 found that piperacillin-tazobactam, cefoxitin, imipenem, meropenem, and tigecycline also showed high activity against Prevotella species.
• The study 7 found that meropenem, piperacillin/tazobactam, chloramphenicol, and metronidazole were likely to be the most effective antibiotics against Prevotella species.