ANAEROBIC AND AEROBIC BACTERIOLOGY OF THE SALIVA AND GINGIVA FROM 16 CAPTIVE KOMODO DRAGONS (VARANUS KOMODOENSIS): NEW IMPLICATIONS FOR THE “BACTERIA AS VENOM” MODEL

Abstract

It has been speculated that the oral flora of the Komodo dragon (Varanus komodoensis) exerts a lethal effect on its prey; yet, scant information about their specific oral flora bacteriology, especially anaerobes, exists. Consequently, the aerobic and anaerobic oral bacteriology of 16 captive Komodo dragons (10 adults and six neonates), aged 2-17 yr for adults and 7-10 days for neonates, from three U.S. zoos were studied. Saliva and gingival samples were collected by zoo personnel, inoculated into anaerobic transport media, and delivered by courier to a reference laboratory. Samples were cultured for aerobes and anaerobes. Strains were identified by standard methods and 16S rRNA gene sequencing when required. The oral flora consisted of 39 aerobic and 21 anaerobic species, with some variation by zoo. Adult dragons grew 128 isolates, including 37 aerobic gram-negative rods (one to eight per specimen), especially Enterobacteriaceae; 50 aerobic gram-positive bacteria (two to nine per specimen), especially Staphylococcus sciuri and Enterococcusfaecalis, present in eight of 10 and nine of 10 dragons, respectively; and 41 anaerobes (one to six per specimen), especially clostridia. All hatchlings grew aerobes but none grew anaerobes. No virulent species were isolated. As with other carnivores, captive Komodo oral flora is simply reflective of the gut and skin flora of their recent meals and environment and is unlikely to cause rapid fatal infection.

Bitten by a Dragon

“…Multiple authors have cast their doubt upon the "bacteria as venom" model. 3,6,7 The bacterial flora isolated from their mouths may reflect bacteria acquired from environmental sources or from feeding on carrion, which is known as the "passive acquisition" model. 3 There are other factors that contribute to the lethality of Komodo dragons.…”

The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends

“…Pathogenic bacteria have also been reported in the saliva of the Komodo dragon (Auffenberg, 1981;Montgomery et al, 2002), and interdenticular sulci may help the proliferation and entering of these toxic bacteria within the prey. Fry et al (2009), however, note that no compelling evidence supports the presence of pathogenic bacteria in the saliva of Varanus komodoensis, a hypothesis supported by Goldstein et al (2013) based on captive Komodo dragons. Yet, Tehrani et al (2008) and Vikrant and Verma (2014) have reported septic effects of varanid bites, and pathogenic bacteria might, therefore, be present and possibly hosted within interdenticular sulci of the crowns of wild varanids.…”

Komodo dragon-inspired synthetic peptide DRGN-1 promotes wound-healing of a mixed-biofilm infected wound

“…The saliva of wild Komodo dragons is thought to contain many different strains of bacteria, some of which are known to cause sepsis. 14, 15 However, this bacteria-laden saliva never sickens the Komodo dragon. Investigators therefore hypothesized that proteins in the dragon's saliva or blood might provide immunity.…”