From the Guidelines
Zosyn (piperacillin/tazobactam) can be used as an option to cover Enterococcus faecalis, but its use should be guided by susceptibility testing of the individual isolate. According to the guidelines by the Surgical Infection Society and the Infectious Diseases Society of America 1, initial empiric anti-enterococcal therapy should be directed against Enterococcus faecalis, and antibiotics that can potentially be used against this organism include ampicillin, piperacillin-tazobactam, and vancomycin. Some key points to consider when using Zosyn for E. faecalis infections include:
- The need for susceptibility testing to guide therapy, as stated in the guidelines 1
- The potential for E. faecalis to develop resistance to piperacillin-tazobactam, highlighting the importance of monitoring and adjusting therapy as needed
- The recommendation to use specific anti-enterococcal antibiotics, such as ampicillin or vancomycin, for serious enterococcal infections, rather than relying on Zosyn alone 1 It is essential to weigh the potential benefits and limitations of using Zosyn for E. faecalis infections, considering factors such as the severity of the infection, the patient's underlying health status, and the risk of resistance development. In clinical practice, the decision to use Zosyn for E. faecalis infections should be made on a case-by-case basis, taking into account the individual patient's needs and the results of susceptibility testing, as recommended by the guidelines 1.
From the FDA Drug Label
Aerobic bacteria Gram-positive bacteria Enterococcus faecalis (ampicillin or penicillin-susceptible isolates only)
Zosyn (piperacillin/tazobactam) has in vitro activity against Enterococcus faecalis, but only for ampicillin or penicillin-susceptible isolates. However, the efficacy of Zosyn in treating clinical infections caused by Enterococcus faecalis has not been established in adequate and well-controlled clinical trials 2.
From the Research
Zosyn (Piperacillin/Tazobactam) Coverage of Enterococcus faecalis
- The effectiveness of Zosyn (piperacillin/tazobactam) against Enterococcus faecalis has been studied in several research papers 3, 4, 5.
- According to a study published in 1998, piperacillin-tazobactam was bactericidal for 14 out of 15 Enterococcus faecalis strains after 24 hours at four times the MIC 3.
- Another study from 1995 found that piperacillin-tazobactam was bactericidal against 6 strains of E. faecalis after 18 hours of incubation at a concentration of 100 mg/l 4.
- A 1993 study evaluated the in vitro activity of piperacillin with and without tazobactam against beta-lactamase-producing Enterococcus faecalis and found that the addition of tazobactam reversed the inoculum effect and resulted in a decrease of > or = 2 log10 in bacterial counts 5.
- More recent studies have focused on the acquisition of resistant bowel flora during treatment with piperacillin-tazobactam and other antibiotics 6, 7.
- A 2016 epidemiological study found that Enterococcus faecalis was one of the most commonly isolated bacteria in complicated intra-abdominal infections, and that piperacillin/tazobactam exhibited activity against 88% of ESBL-positive Enterobacteriaceae isolates 7.