Tetracycline Residue Rapid Test Strip (Milk)

Construction of heterojunction photocatalyst is a very useful approach to enhance photocatalytic activity. In particular, the coupling of narrow-band-gap semiconductor and wide-band-gap semiconductor can solve their inherent drawbacks, simultaneously optimizing the photoabsorption and redox capabilities. In this work, a series of BiOI/Bi2O2[BO2(OH)] heterojunction photocatalysts were synthesized by an in-situ precipitation method. The crystal structure, morphology and surface chemical composition were analyzed to confirm the heterojunction formation. BiOI/Bi2O2[BO2(OH)] heterojunctions show increased specific surface area, which can provide more absorptive and catalytic sites for pollutants. Particularly, the recombination of photogenerated electrons and holes in BiOI/Bi2O2[BO2(OH)] was severely inhibited. Compared to the pristine BiOI and Bi2O2[BO2(OH)], the BiOI/Bi2O2[BO2(OH)] heterojunctions demonstrated substantially enhanced visible-light driven photocatalytic activity for degradation of various contaminants, including methyl orange, methylene blue and tetracycline hydrochloride. The superoxide radicals (O-center dot(2)-) and holes (h(+)) were determined as the main active species and played crucial role in the photodegradation process, which also verified the formation of type II heterojunction between BiOI and Bi2O2[BO2(OH)]. This work provides an efficient heterojunction photocatalyst for environmental remediation.

American mink (Neovison vison) is a significant source of global fur production. Except for a few studies from Denmark and Canada reporting antimicrobial resistance in bacteria isolated from clinical cases, studies from the general mink population are scarce and absent in the United States. Mink feces (n = 42) and feed (n = 8) samples obtained from a mink farm were cultured for the enumeration and detection of tetracycline-resistant (TET (R))- and third-generation cephalosporin-resistant (TGC (R))-Escherichia coli. Isolates were characterized phenotypically for their resistance to other antibiotics and genotypically for resistance genes. TET (R) E. coliwere detected from 98% of feces samples (mean concentration = 6 log(10)) and from 100% of feed samples (mean concentration = 3.2 logs). Among TET (R) E. coliisolates, 44% (n = 41) of fecal- and 50% (n = 8) of feed isolates were multidrug resistant (MDR; resistance to >= 3 antimicrobial classes), and 96% (n = 49) of TET (R) isolates were positive fortet(A) and/ortet(B). TGC (R) E. coliwere detected from 95% of feces and 75% of feed samples with 78% (n = 40) of fecal isolates, and all six of the feed isolates were MDR. Nearly two-thirds (65%) of the TGC (R) E. coliisolates (n = 46) were positive forbla(CMY-2); the remaining 35% were positive forbla(CTX-M,)with thebla(CTX-M-14)being the predominant (75%,n = 16) variant detected. Metagenomic DNA was extracted directly from feces and feed samples, and it was tested for 84 antimicrobial resistance genes by using quantitative polymerase chain reaction (PCR) array; selected genes were also quantified by droplet digital PCR. The genes detected from the fecal samples belonged mainly to five antimicrobial classes: macrolide-lincosamide-streptogramin B (MLSB; 100% prevalence), TETs (88.1%), beta-lactams (71.4%), aminoglycosides (66.7%), and fluoroquinolones (47.6%). beta-Lactam, MLSB, and TET resistance genes were also detected from feed samples. Our study serves as a baseline for further studies and to streamline antimicrobial use in mink production in accordance with current regulations as in food animals.