From the Research
For blood culture positive Aggregatibacter with a positive culture incubation time of 30 hours, the recommended antibiotic treatment is a third-generation cephalosporin such as ceftriaxone 2g IV once daily for 2-4 weeks, as supported by the most recent study 1. This recommendation is based on the fact that Aggregatibacter species are fastidious gram-negative bacteria that often cause endocarditis, but can also cause other infections including pneumonia and abscesses. The relatively long incubation time of 30 hours is typical for these slow-growing organisms, which require special culture conditions for optimal growth. Some key points to consider when treating Aggregatibacter infections include:
- The use of alternative antibiotics such as ampicillin-sulbactam 3g IV every 6 hours, or a fluoroquinolone such as ciprofloxacin 400mg IV twice daily or levofloxacin 750mg IV once daily if the patient has a beta-lactam allergy 2.
- The importance of susceptibility testing to guide final antibiotic selection, as resistance patterns vary 3.
- The potential for combination therapy with ceftriaxone plus gentamicin 5mg/kg IV once daily for the first 2 weeks in cases of severe infections or endocarditis 1.
- The possibility of oral step-down therapy with amoxicillin-clavulanate 875/125mg twice daily or ciprofloxacin 500mg twice daily to complete the treatment course after clinical improvement 2. It's also worth noting that the optimal incubation time for blood cultures has been evaluated in recent studies, with one study suggesting that a 4-day incubation time is sufficient for the Virtuo system and media 4. However, this does not directly impact the recommended antibiotic treatment for Aggregatibacter infections.