Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Aggregatibacter is a genus in the phylum Proteobacteria (Bacteria), which contains three species, namely:

• A. actinomycetemcomitans ( (Klinger 1912) Nørskov-Lauritsen and Kilian 2006, (type species of the genus); Greek noun aktis, aktinos (ἀκτίς, ἀκτῖνος), a beam; Greek mukēs -ētos, mushroom or other fungus; New Latin actinomyces –etis, an actinomycete; Latin comitans, accompanying; New Latin actinomycetemcomitans, accompanying an actinomycete)^[1]
• A. aphrophilus (Khairat 1940) Nørskov-Lauritsen and Kilian 2006, Ancient Greek aphros, foam; New Latin philus from Greek philos (φίλος) meaning friend, loving; New Latin aphrophilus, foam-loving)^[2]
• A. segnis (Kilian 1977) Nørskov-Lauritsen and Kilian 2006,Latin segnis, slow, sluggish, inactive)^[3]

• 1. Endocarditis^[4]

• 1.1 Adults

• Preferred regimen (1): Ceftriaxone 2 g/day TV/IM q24h for 4 weeks
• Preferred regimen (2): Ampicillin-sulbactam 12 g/day TV q6h for 4 weeks
• Preferred regimen (3): Ciprofloxacin 1000 mg PO q24h OR 800 mg/day IV q12h for 4 weeks

• 1.2 Pediatrics

• Preferred regimen (1): Ceftriaxone 100 mg/kg/day TV/IM q24h for 4 weeks
• Preferred regimen (2): Ampicillin-sulbactam 300 mg/kg/day TV q6h/q4h for 4 weeks
• Preferred regimen (3): Ciprofloxacin 20-30 mg/kg/day IV/PO bid for 4 weeks
• Note (1): Floroquinolone therapy recommended for patients unable to tolerate Cephalosporin and ampicillin thearpy
• Note (2): For patients < 18 years, Flourouinolones are generally not recommended
• Note (3): For patients with endocarditis involving the prosthetic cardiac valve or other prosthetic cardiac material should be treated for 6 weeks

• 2. Abscess ^[5]

• Note: The small number of patients reported and the variety of antibiotics used, do not permit identification of the optimal therapeutic regimen for this organism.

• Microbiology