Antimicrobial resistance against colistin has emerged worldwide and is threatening the efficacy of colistin treatment of multi-resistant Gram-negative bacteria. In this study, PCRs were used to detect mcr genes (mcr-1, mcr-2, mcr-3) in 213 anal and 1,339 nasal swabs from pigs (n = 1,454) in nine provinces of China, and 1,696 cloacal and 1,647 oropharyngeal samples from poultry (n = 1,836) at live-bird markets in 24 provinces. The mcr-1 prevalences in pigs (79.2%) and geese (71.7%) were significantly higher than in chickens (31.8%), ducks (34.6%) and pigeons (13.1%). The mcr-2 prevalence in pigs was 56.3%, significantly higher than in chickens (5.5%), ducks (2.3%), geese (5.5%) and pigeons (0%). The mcr-3 prevalences in pigs (18.7%), ducks (13.8%) and geese (11.9%) were significantly higher than in chickens (5.2%) and pigeons (5.1%). In total, 173 pigs and three chickens were positive for all three mcr genes. The prevalences of the mcr were significantly higher in nasal/oropharyngeal swabs than in the anal /cloacal swabs. Phylogenetic studies identified 33 new mcr-2 variants and 12 new mcr-3 variants. This study demonstrates high prevalences of mcr in pigs and poultry in China, and indicates there is need for more thorough surveillance and control programs to prevent further selection of colistin resistance.

Flies have the capacity to transfer pathogens between different environments, acting as one of the most important vectors of human diseases worldwide. In this study, we trapped flies on a university campus and tested them for mobile resistance genes against colistin, a last-resort antibiotic in human medicine for treating clinical infections caused by multidrug-resistant Gram-negative bacteria. Quantitative PCR assays we developed showed that 34.1% of (86/252) and 51.1% of (23/45) isolates were positive for the gene, 1.2% of (3/252) and 2.2% of (2.2%, 1/45) isolates were positive for, and 5.2% of (13/252) and 44.4% of (20/45) isolates were positive for Overall, 4.8% (9/189) of bacteria isolated from the flies were positive for the gene (: 8.3%, 4/48; : 12.5%, 1/8;: 11.8%, 2/17; : 4.9%, 2/41), while none were positive for and Four-positive isolates (two and two) from blow flies trapped near a dumpster had a MIC for colistin above 4 mg/ml. This study reports carriage in spp. and detection of and after their initial identification in Belgium and China, respectively. This study suggests that flies might contribute significantly to the dissemination of bacteria, carrying these genes into a large variety of ecological niches. Further studies are warranted to explore the roles that flies might play in the spread of colistin resistance genes. Antimicrobial resistance is recognized as one of the most serious global threats to human health. An option for treatment of the Gram-negative ESKAPE (, ,, ,, and species) bacteria with multiple drug resistance was the reintroduction of the older antibiotic colistin. However, a mobile colistin resistance gene () has recently been found to occur widely; very recently, two other colistin resistance genes ( and ) have been identified in Belgium and China, respectively. In this study, we report the presence of colistin resistance genes in flies. This study also reports the carriage of colistin resistance genes in the genus and detection of and after their initial identification. This study will stimulate more in-depth studies to fully elucidate the transmission mechanisms of the colistin resistance genes and their interaction.

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Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen that shows resistance to many antibiotics and is usually associated with serious infections. Having the ability for biofilm formation increases resistance to antibiotics. Sanguisorba officinalis L. is a perennial plant that is distributed in the northern districts of China and has been used as a traditional Chinese medicine. In this study, the effect of S. officinalis on MRSA strain SA3 isolated from a dairy cow with mastitis was evaluated by testing the growth and biofilm formation ability of MRSA cultured with or without ethanol extracts of S. officinalis. The results showed that the ethanol extract of S. officinalis strongly inhibited the biofilm formation of MRSA. With a confocal laser scanning microscope system, we observed that the biofilm structure of the test group with the addition of S. officinalis appeared looser and had less biomass compared with the control group without S. officinalis. Furthermore, we found that the transcript levels of the icaADBC operon remarkably decreased upon addition of the ethanol extract of S. officinalis, indicating that S. officinalis inhibits biofilm formation of MRSA in an ica-dependent manner.