リョクノウキン Quorum sensing キコウ ト コウキンヤク テイコウセイ ニツイテ

The opportunistic pathogen Pseudomonas aeruginosa causes immunocompromised individuals and patients with cystic fibrosis to serious nosocomial infections. Although we choose the most suitable antibiotics on the basis of minimum inhibitory concentration (MIC), it is often difficult to eradicate pathogen. This phenomenon is called antibiotic tolerance, which is different from antibiotic resistance. Antibiotic tolerance is the ability of bacteria to survive but not grow in the presence of antibiotics. To understand the mechanism of antibiotic tolerance, we investigated the relation of quorum sensing system and antibiotic tolerance. With 4 x MIC or 8 x MIC of ofloxacin, the lasR mutant and the lasI mutant were killed more rapidly than the parental strain, but the survival rates of the rhlR mutant and the rhlI mutant were the same level of the parental strain. And with 8 x MIC of ofloxacin, the lasR-rhlR double knockout mutant and the lasI-rhlI double knockout mutant were killed more rapidly than the parental strain. To investigate these phenomena more detail, we measured the promoter activities of lasR and rhlR genes. The promoter activity of the lasR was induced with ofloxacin in the logarithmic and the stationary phase cells, but the promoter activity of the rhlR was not. Continuously, we measured the expression levels of lasR, lasI, rhlR, and rhlI. The expression of the lasR was induced with lower concentration of ofloxacin, but higher concentration of ofloxacin repressed expression of the lasR. And expression of lasI, rhlR and rhlI genes were repressed or irrelevant to the concentration of ofloxacin. In conclusion, we revealed that the las quorum sensing system was related to the antibiotic tolerance, and the antibiotic tolerance was promoted by the las quorum sensing system

Emergence of Staphylococcus aureus Carrying Multiple Drug Resistance Genes on a Plasmid Encoding Exfoliative Toxin B

Job file for the creation/design of stained glass from either the Charles J. Connick Studio (1912-1945) or the Charles J. Connick Associates studio (1945-1986). The job file contains a job number, location information, date of completion, size, contact information, price, and a description of the project. This particular job file contains information on a job located at: Albany, New York. Saint James Church

First genomic characterization of blavim-1 and mcr-9-coharbouring enterobacter hormaechei isolated from food of animal origin

We describe here the complete genome sequence of an Enterobacter hormaechei ST279 coharbouring blaVIM-1 and mcr-9 recovered from uncooked beef patty in June 2017, Egypt. The tested isolate was resistant to carbapenem but susceptible to colistin (minimum inhibitory concentration (MIC), 0.5 μg/mL). The antimicrobial susceptibility profile and conjugation experiments were performed. The entire genome was sequenced by the Illumina MiniSeq and Oxford Nanopore methods. The blaVIM-1 and mcr-9 genes are carried on the same IncHI2/pMLST1 plasmid, pMS37a (Size of 270.9 kb). The mcr-9 gene was located within the physical boundaries demarcated by two insertion elements IS903 (upstream) and IS1 (downstream) but did not possess the downstream regulatory genes (qseC/qseB) which regulate the expression of mcr- 9. Therefore, the mcr-9 might be silently disseminated among carbapenem-resistant Enterobacterales. In addition to blaVIM-1 and mcr-9, plasmid pMS37a harbored various antibiotic resistance genes including aac(6’)-Il, ΔaadA22, aac(6’)-Ib-cr, sul1, dfrA1 and tetA. To the best of our knowledge, this is the first report of a blaVIM-1 and mcr-9-coharbouring E. hormaechei isolate of food origin worldwide. The identification of a multidrug-resistant VIM-1 and mcr-9 positive Enterobacter hormaechei isolate from food is worrisome as retail meat and meat products could serve as a vehicle for these MDR bacteria, which could be transferred between animals and humans through the food chain. It further highlights that Enterobacterales co-producing MCR and carbapenemases being found in the food chain indeed correspond to a One- Health issue, highlighting the need for serious steps to prevent their further dissemination

NFATc1 mediates Toll-like receptor-independent innate immune responses during Trypanosoma cruzi infection.

Host defense against the intracellular protozoan parasite Trypanosoma cruzi depends on Toll-like receptor (TLR)-dependent innate immune responses. Recent studies also suggest the presence of TLR-independent responses to several microorganisms, such as viruses, bacteria, and fungi. However, the TLR-independent responses to protozoa remain unclear. Here, we demonstrate a novel TLR-independent innate response pathway to T. cruzi. Myd88(-/-)Trif(-/-) mice lacking TLR signaling showed normal T. cruzi-induced Th1 responses and maturation of dendritic cells (DCs), despite high sensitivity to the infection. IFN-gamma was normally induced in T. cruzi-infected Myd88(-/-)Trif(-/-) innate immune cells, and further was responsible for the TLR-independent Th1 responses and DC maturation after T. cruzi infection. T. cruzi infection induced elevation of the intracellular Ca(2+) level. Furthermore, T. cruzi-induced IFN-gamma expression was blocked by inhibition of Ca(2+) signaling. NFATc1, which plays a pivotal role in Ca(2+) signaling in lymphocytes, was activated in T. cruzi-infected Myd88(-/-)Trif(-/-) innate immune cells. T. cruzi-infected Nfatc1(-/-) fetal liver DCs were impaired in IFN-gamma production and DC maturation. These results demonstrate that NFATc1 mediates TLR-independent innate immune responses in T. cruzi infection

Genomic landscape of blaGES-5- and blaGES-24-harboring Gram-negative bacteria from hospital wastewater: emergence of class 3 integron-associated blaGES-24 genes

ABSTRACT: Objectives: This study aimed to characterize Gram negative bacteria carrying blaGES carbapenemase genes detected in wastewater from a hospital with no history of detection of clinical isolates producing GES carbapenemases. Methods: Six hospital effluent samples were screened for carbapenemase-producing organisms (CPO) using CHROMagar mSuperCARBA and MacConkey agar with 1 µg/mL imipenem. Polymerase chain reaction (PCR) amplification and sequencing of carbapenemase genes, multilocus sequence typing, antimicrobial susceptibility testing, and whole-genome sequencing were performed. Results: Among 21 CPO isolates, 11 Klebsiella spp. and 5 Enterobacter kobei isolates carried blaGES-24, and 4 E. roggenkampii and 1 Pseudomonas aeruginosa isolates carried blaGES-5. Genomic analysis of 8 representative isolates comprising 6 blaGES-24-positive and 2 blaGES-5-positive revealed that class 3 integrons with complete or defective Tn402-like transposition modules were predominantly associated with two tandem copies of blaGES-24. Furthermore, a total of 5 new class 3 integrons, In3-18 to In3-22, were identified among 5 blaGES-24 and 1 blaGES-5 plasmids. One strain each of K. pneumoniae subsp. pneumoniae and K. quasipneumoniae subsp. similipneumoniae harboring blaGES-24 plasmids also carried a rare blaVEB-1-positive class 1 integron on a non-typeable plasmid, where these blaVEB-1 plasmids had high sequence similarity. Virulence gene profiles differed between Klebsiella spp. and Enterobacter spp.; the former harbored type III fimbriae cluster, salmochelin, and T6SS type i2 gene clusters, while the latter had curli pili operon, aerobactin, T2SS gene clusters, and T6SS type i3 gene clusters. Conclusion: Our findings confirmed the linkage of blaGES-24 with rare Tn402-like class 3 integrons and the structural diversity of their gene cassette arrays

National genomic surveillance integrating standardized quantitative susceptibility testing clarifies antimicrobial resistance in Enterobacterales

Abstract Antimicrobial resistance is a global health concern; Enterobacterales resistant to third-generation cephalosporins (3GCs) and carbapenems are of the highest priority. Here, we conducted genome sequencing and standardized quantitative antimicrobial susceptibility testing of 4,195 isolates of Escherichia coli and Klebsiella pneumoniae resistant to 3GCs and Enterobacterales with reduced meropenem susceptibility collected across Japan. Our analyses provided a complete classification of 3GC resistance mechanisms. Analyses with complete reference plasmids revealed that among the bla CTX-M extended-spectrum β-lactamase genes, bla CTX-M-8 was typically encoded in highly similar plasmids. The two major AmpC β-lactamase genes were bla CMY-2 and bla DHA-1. Long-read sequencing of representative plasmids revealed that approximately 60% and 40% of bla CMY-2 and bla DHA-1 were encoded by such plasmids, respectively. Our analyses identified strains positive for carbapenemase genes but phenotypically susceptible to carbapenems and undetectable by standard antimicrobial susceptibility testing. Systematic long-read sequencing enabled reconstruction of 183 complete plasmid sequences encoding three major carbapenemase genes and elucidation of their geographical distribution stratified by replicon types and species carrying the plasmids and potential plasmid transfer events. Overall, we provide a blueprint for a national genomic surveillance study that integrates standardized quantitative antimicrobial susceptibility testing and characterizes resistance determinants