From the FDA Drug Label
Piperacillin and tazobactam is an antibacterial drug [see Microbiology (12.4)].
The antibiotic that is good for a scrotal abscess growing gram-negative bacilli is piperacillin-tazobactam (IV), as it has antibacterial activity against gram-negative bacilli 1.
- Key points:
- Piperacillin and tazobactam has antibacterial activity
- Effective against gram-negative bacilli
- Administered intravenously (IV)
- Dose: 2.25 grams, 3.375 grams, or 4.5 grams, with tazobactam doses of 0.25 grams, 0.375 grams, or 0.5 grams, respectively.
From the Research
For a scrotal abscess growing gram-negative bacilli, empiric treatment with a combination of antibiotics such as ciprofloxacin and metronidazole is typically recommended, but the most recent and highest quality study suggests that cefazolin may be effective against gram-negative anaerobic bacilli like Prevotella bivia. The choice of antibiotic should be based on the suspected or confirmed causative organism and its susceptibility pattern. Some key points to consider in the management of scrotal abscesses include:
- The importance of surgical drainage in addition to antibiotic therapy
- The need to monitor patients for improvement in symptoms and to reassess treatment if there is no improvement within 48-72 hours
- The potential for gram-negative bacilli to produce beta-lactamases that confer resistance to some antibiotics, as noted in studies such as 2
- The variety of organisms that can cause scrotal abscesses, including gram-negative bacilli like Escherichia coli, Klebsiella, and Pseudomonas species, as well as anaerobic bacteria like Prevotella bivia, as reported in 3
- The possibility of scrotal abscesses being caused by other types of organisms, such as fungi like Candida glabrata, as described in 4 In terms of specific antibiotic regimens, a combination of a fluoroquinolone like ciprofloxacin (500 mg orally twice daily) and metronidazole (500 mg orally three times daily) for 7-14 days may be effective, as suggested by the example answer. Alternatively, a third-generation cephalosporin like ceftriaxone (1-2 g IV daily) combined with metronidazole may be used, as noted in the example answer. However, the most recent and highest quality study, 3, suggests that cefazolin may be effective against gram-negative anaerobic bacilli like Prevotella bivia, and this should be considered when choosing an antibiotic regimen. Ultimately, the choice of antibiotic should be tailored to the specific organism's susceptibility pattern and the patient's clinical response, as emphasized in 5 and 6.