TY - JOUR
T1 - Widespread Occurrence of Phage-encoded Exotoxin Genes in Terrestrial and Aquatic Environments in Southern California
AU - Casas, Veronica
AU - Miyake, Jon
AU - Balsley, Heather
AU - Roark, Julie
AU - Telles, Serena
AU - Leeds, Steven
AU - Zurita, Ivan
AU - Breitbart, Mya
AU - Bartlett, Doug
AU - Azam, Farooq
AU - Rohwer, Forest
PY - 2006/1/1
Y1 - 2006/1/1
N2 - Many human diseases are caused by pathogens that produce exotoxins. The genes that encode these exotoxins are frequently encoded by mobile DNA elements such as plasmids or phage. Mobile DNA elements can move exotoxin genes among microbial hosts, converting avirulent bacteria into pathogens. Phage and bacteria from water, soil, and sediment environments represent a potential reservoir of phage- and plasmid-encoded exotoxin genes. The genes encoding exotoxins that are the causes of cholera, diphtheria, enterohemorrhagic diarrhea, and Staphylococcus aureus food poisoning were found in soil, sediment, and water samples by standard PCR assays from locations where the human diseases are uncommon or nonexistent. On average, at least one of the target exotoxin genes was detected in ∼15% of the more than 300 environmental samples tested. The results of standard PCR assays were confirmed by quantitative PCR (QPCR) and Southern dot blot analyses. Agreement between the results of the standard PCR and QPCR ranged from 63% to 84%; and the agreement between standard PCR and Southern dot blots ranged from 50% to 66%. Both the cholera and shiga exotoxin genes were also found in the free phage DNA fraction. The results indicate that phage-encoded exotoxin genes are widespread and mobile in terrestrial and aquatic environments.
AB - Many human diseases are caused by pathogens that produce exotoxins. The genes that encode these exotoxins are frequently encoded by mobile DNA elements such as plasmids or phage. Mobile DNA elements can move exotoxin genes among microbial hosts, converting avirulent bacteria into pathogens. Phage and bacteria from water, soil, and sediment environments represent a potential reservoir of phage- and plasmid-encoded exotoxin genes. The genes encoding exotoxins that are the causes of cholera, diphtheria, enterohemorrhagic diarrhea, and Staphylococcus aureus food poisoning were found in soil, sediment, and water samples by standard PCR assays from locations where the human diseases are uncommon or nonexistent. On average, at least one of the target exotoxin genes was detected in ∼15% of the more than 300 environmental samples tested. The results of standard PCR assays were confirmed by quantitative PCR (QPCR) and Southern dot blot analyses. Agreement between the results of the standard PCR and QPCR ranged from 63% to 84%; and the agreement between standard PCR and Southern dot blots ranged from 50% to 66%. Both the cholera and shiga exotoxin genes were also found in the free phage DNA fraction. The results indicate that phage-encoded exotoxin genes are widespread and mobile in terrestrial and aquatic environments.
KW - phage
KW - cholera toxin
KW - diphtheria toxin
KW - shiga toxin
KW - Staphylococcus enterotoxin A
KW - horizontal gene transfer
UR - https://digitalcommons.usf.edu/msc_facpub/782
UR - https://doi.org/10.1111/j.1574-6968.2006.00345.x
U2 - 10.1111/j.1574-6968.2006.00345.x
DO - 10.1111/j.1574-6968.2006.00345.x
M3 - Article
C2 - 16842371
VL - 261
JO - FEMS Microbiology Letters
JF - FEMS Microbiology Letters
ER -