Wide variety of antibiotic-resistance genes found in manure
Cow manure harbors a "remarkable" diversity of antibiotic-resistance genes and could be a reservoir for new types of antibiotic resistance (AR) as the genes transfer to soil when manure is used as crop fertilizer, according to a study released today in mBio, published by the American Society of Microbiology (ASM).
The researchers, from Yale University and the University of Connecticut, extracted DNA from five manure samples from four cows at a dairy farm in Connecticut, says a story from Agence France-Presse (AFP). Using a screening-plus-sequencing method, they identified 80 unique AR genes. When applied to a laboratory strain of Escherichia coli, the genes rendered the bacteria resistant to beta-lactams, aminoglycosides, tetracycline, or chloramphenicol.
When applied to a lab strain of E. coli, the genes made the bacteria resistant to certain well-known antibiotics, including penicillin and tetracycline.
When we hit that wall of antibiotic resistance, we will either have alternatives or be well on the way to them.
Heads up, New York: A near-invincible skin bacteria has invaded your gyms—and your homes
....branches started breaking off like crazy around the time of the 1995-2002 surge in US consumption of fluoroquinolone—often known as ciprofloxacin or norfloxacin—some 40% of which was for non-FDA-approved maladies. Because fluoroquinolone is secreted through sweat, its comes in contact with way more strains of bacteria than other antibiotics. And that, says Uhlemann, has given USA300 substrains ample opportunities to adapt.
But after they adapted, how did these new strains spread?
Again, their prevalence makes it hard to tell. Despite the study’s large sample, in only a handful of cases were the researchers able directly to connect an infection in one household to another elsewhere in the community, as you would with, say, the ebola virus, says Uhlemann.
“[With ebola] you have a case in one village and then the next village—you can almost draw a line from point A to point B to point C,” she says. “But we’re seeing [USA300] all over—you can’t point to where it came from. It was probably introduced multiple times and then diversified.”