Isolation of faecal coliform bacteria from the American alligator (Alligator mississippiensis)

• Published in: Journal of applied microbiology Vol. 108; no. 3; pp. 965 - 973
• Main Authors: Johnston, M.A, Porter, D.E, Scott, G.I, Rhodes, W.E, Webster, L.F
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.03.2010; Blackwell Publishing Ltd; Blackwell; Oxford University Press
• Subjects: Aeromonas hydrophila; alligator; Alligator mississippiensis; Alligators; Alligators and Crocodiles - microbiology; Animals; Aquatic animals; Aquatic habitats; Aquatic reptiles; Bacteria; Biochemical tests; Biological and medical sciences; Citrobacter; Cloaca - microbiology; Coastal waters; Coliforms; Colony Count, Microbial; Contamination; E coli; Ecosystem; Edwardsiella tarda; Enterobacter cloacae; Enterobacteriaceae - isolation & purification; Enumeration; Environmental Monitoring; Escherichia coli; faecal coliform; Fecal coliforms; Feces; Feces - microbiology; Female; Fresh Water - microbiology; Freshwater; Fundamental and applied biological sciences. Psychology; indicators; Male; Microbiology; Plesiomonas shigelloides; reptiles; Salmonella; South Carolina; Surface water; Water analysis; Water Microbiology; Water quality; Water sampling; South Carolina; USA, South Carolina; ANW, USA, South Carolina; alligator; Applied microbiology; reptiles; Crocodilia; Coliforms; indicators; Vertebrata; Alligator mississippiensis; Water quality; Bacteria; Isolation; Reptilia; Feces; faecal coliform
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/j.1365-2672.2009.04498.x

To determine whether American alligators (Alligator mississippiensis) are an unrecognized poikilothermic source of faecal coliform and/or potential pathogenic bacteria in South Carolina's coastal waters. Bacteria from the cloaca of American alligators, as well as bacteria from surface water samples from their aquatic habitat, were isolated and identified. The predominant enteric bacteria identified from alligator samples using biochemical tests included Aeromonas hydrophila, Citrobacter braakii, Edwardsiella tarda, Escherichia coli, Enterobacter cloacae, Plesiomonas shigelloides and putative Salmonella, and these were similar to bacteria isolated from the surface waters in which the alligators inhabited. Based on most-probable-number enumeration estimates from captive alligator faeces, faecal coliform bacteria numbered 8·0 x 10⁹ g⁻¹ (wet weight) of alligator faecal material, a much higher concentration than many other documented endothermic animal sources. A prevalence of enteric bacteria, both faecal coliforms and potential pathogens, was observed in American alligators. The high faecal coliform bacterial density of alligator faeces may suggest that alligators are a potential source of bacterial contamination in South Carolina coastal waters. These findings help to increase our understanding of faecal coliform and potential pathogenic bacteria from poikilothermic reptilian sources, as there is the potential for these sources to raise bacterial water quality levels above regulatory thresholds.