From the Guidelines
For a scrotal abscess growing gram-negative bacilli, the most effective alternative to Zosyn (piperacillin-tazobactam) is meropenem (1g IV every 8 hours) due to its broad-spectrum coverage and efficacy against gram-negative bacilli, as suggested by the 2018 study on hospital-acquired pneumonia in ICU 1. When considering treatment options, it's essential to prioritize antibiotics with activity against gram-negative bacilli, including Pseudomonas aeruginosa.
- Meropenem is a carbapenem with a broad spectrum of activity, including against gram-negative bacilli, making it a suitable alternative to Zosyn.
- Other options like cefepime (4 to 6 g/d) or ceftazidime (3 to 6 g/d) may also be considered, but meropenem is generally preferred due to its broader coverage and lower resistance rates 1.
- Fluoroquinolones like ciprofloxacin (400mg IV twice daily or 500-750mg orally twice daily) can be effective, but their use should be guided by culture and sensitivity results due to potential resistance issues.
- Surgical drainage is often necessary alongside antibiotics for complete resolution of the abscess, as emphasized in the 2018 WSES/SIS-E consensus conference recommendations for the management of skin and soft-tissue infections 1.
- The choice of antibiotic should ideally be guided by culture and sensitivity results, and treatment duration typically ranges from 7-14 days depending on clinical response.
- Patients should be monitored for improvement in symptoms, including pain, swelling, and fever, with consideration for narrowing antibiotic coverage once culture results are available.
From the FDA Drug Label
The most common primary cIAI diagnosis was appendiceal perforation or peri-appendiceal abscess, occurring in 44.7% of patients. Clinical cure rates at the TOC visit by pathogen in the mMITT population are presented in Table 16. Aerobic Gram-negative group or pathogen AVYCAZ plus metronidazolea n/N (%) Meropenemb n/N (%) Enterobacteriaceae 272/334 (81.4) 305/353 (86.4) Escherichia coli 218/271 (80.4) 248/285 (87.0) Klebsiella pneumoniae 40/51 (78.4) 37/49 (75. 5) At baseline, 111 patients in the mMITT population had Gram-negative isolates that were not susceptible to ceftazidime, including 61 patients with E. coli and 26 patients with K. pneumoniae isolates. Cure rates were 39/47 (83.0%) in patients who received AVYCAZ and 55/64 (85. 9%) of patients who received meropenem.
Avibactam (AVYCAZ) is an option for treating infections caused by gram-negative bacilli, including those that are resistant to ceftazidime.
- Key points:
- AVYCAZ has been shown to be effective against a range of gram-negative pathogens, including Enterobacteriaceae, E. coli, and Klebsiella pneumoniae.
- Clinical cure rates for AVYCAZ were similar to those for meropenem in patients with complicated intra-abdominal infections.
- AVYCAZ may be a suitable alternative to Zosyn for treating scrotal abscesses caused by gram-negative bacilli, especially in cases where the pathogens are resistant to ceftazidime 2.
From the Research
Antibiotic Options for Scrotal Abscess with Gram-Negative Bacilli
- Besides Zosyn (piperacillin/tazobactam), other antibiotic options for treating scrotal abscess with gram-negative bacilli include:
- Cefiderocol, a siderophore cephalosporin with activity against carbapenem-resistant and multidrug-resistant gram-negative bacilli 3
- Cefepime, a broad-spectrum cephalosporin with in vitro activity against gram-negative bacilli, including Pseudomonas aeruginosa and Enterobacteriaceae 4
- Piperacillin/tazobactam in combination with an aminoglycoside, such as gentamicin, or a fluoroquinolone, such as ciprofloxacin or levofloxacin, which has been shown to be effective against Pseudomonas aeruginosa 5
Mechanism of Action and Efficacy
- Cefiderocol has a unique mechanism of action, utilizing its siderophore-like property to enter the bacterial periplasmic space and inhibit cell wall synthesis 3
- Cefepime has been shown to be more active against Enterobacteriaceae than ceftazidime, and its in vitro potency against methicillin-sensitive Staphylococcus aureus is comparable to that of ceftazidime 4
- The combination of a beta-lactam antibiotic, such as piperacillin/tazobactam or cefepime, with an aminoglycoside or a fluoroquinolone has been shown to be effective against Pseudomonas aeruginosa, with no significant difference in synergistic activity between the different combinations 5
Clinical Considerations
- The choice of antibiotic should be based on the severity of the infection, the susceptibility of the causative organism, and the patient's underlying medical conditions 6, 3, 4, 5
- It is essential to note that scrotal abscesses can have varied etiologies and associations, and treatment should be tailored to the individual patient's needs 7