In vivo fitness of sul gene-dependent sulfonamide-resistant Escherichia coli in the mammalian gut.

The widespread sulfonamide resistance genes sul1, sul2, and sul3 in food and gut bacteria have attracted considerable attention. In this study, we assessed the in vivo fitness of sul gene-dependent sulfonamide-resistant Escherichia coli, using a murine model. High fitness costs were incurred for sul1 and sul3 gene-dependent E. coli strains in vivo. A fitness advantage was found in three of the eight mice after intragastric administration of sul2 gene-dependent E. coli strains. We isolated three compensatory mutant strains (CMSs) independently from three mice that outcompeted the parent strain P2 in vivo. Whole-genome sequencing revealed seven identical single nucleotide polymorphism (SNP) mutations in the three CMSs compared with strain P2, an additional SNP mutation in strain S2-2, and two additional SNP mutations in strain S2-3. Furthermore, tandem mass tag-based quantitative proteomic analysis revealed abundant differentially expressed proteins (DEPs) in the CMSs compared with P2. Of these, seven key fitness-related DEPs distributed in two-component systems, galactose and tryptophan metabolism pathways, were verified using parallel reaction monitoring analysis. The DEPs in the CMSs influenced bacterial motility, environmental stress tolerance, colonization ability, carbohydrate utilization, cell morphology maintenance, and chemotaxis to restore fitness costs and adapt to the mammalian gut environment.IMPORTANCESulfonamides are traditional synthetic antimicrobial agents used in clinical and veterinary medical settings. Their long-term excessive overuse has resulted in widespread microbial resistance, limiting their application for medical interventions. Resistance to sulfonamides is primarily conferred by the alternative genes sul1, sul2, and sul3 encoding dihydropteroate synthase in bacteria. Studying the potential fitness cost of these sul genes is crucial for understanding the evolution and transmission of sulfonamide-resistant bacteria. In vitro studies have been conducted on the fitness cost of sul genes in bacteria. In this study, we provide critical insights into bacterial adaptation and transmission using an in vivo approach.

Corrigendum: Antimicrobial resistance and genomic characterization of Escherichia coli from pigs and chickens in Zhejiang, China.

[This corrects the article DOI: 10.3389/fmicb.2022.1018682.].

Antimicrobial resistance and genomic characterization of Escherichia coli from pigs and chickens in Zhejiang, China.

Escherichia coli is considered an opportunistic pathogen and an indicator for antimicrobial resistance (AMR) monitoring. Despite many reports on its AMR monitoring, studies based on genome-based analysis of AMR genes are still insufficient. Here, 181 E. coli strains were isolated from anal swab samples collected from pigs and chickens of animal farms located in Eastern China and sequenced through the Illumina platform. The results showed that 87.85% (159/181) of the E. coli isolates were multidrug-resistant (MDR). Ampicillin (AMP)- spectinomycin (SPT)- tetracycline (TET)- florfenicol (FFC)- sulfisoxazole (SF)- trimethoprim/sulfamethoxazole (SXT) was the predominant AMR pattern. By whole-genome sequencing, we found that ST10 (10.49%, 19/181) and ST48 (7.18%, 13/181) were major sequence types. IncFIB and IncX1 were the most prevalent plasmid replicons. The AMR genes bla NDM-5 (1.10%, 2/181), mcr-1 (1.10%, 2/181), tet(X4) (1.10%, 2/181), and cfr (6.08%, 2/181) were also found in these isolates. In addition, among the 169 virulence genes detected, we identified astA (37.02%, 67/181), hlyA (1.66%, 3/181), hlyB (1.66%, 3/181) and hlyD (1.66%, 3/181), which were closely related to heat-stable enterotoxin 1 and α-hemolysin. In addition, there were 33 virulence genes associated with the iron uptake system, and 46 were adhesion-related genes. Our study highlighted the need for routine surveillance of AMR with advanced genomic approaches, providing up-to-date data on the prevalence of AMR for the development and execution of antimicrobial stewardship policy.

Genome Assessment of Carbapenem- and Colistin-Resistant Escherichia coli from Patients in a Sentinel Hospital in China.

Antimicrobial-resistant (AMR) pathogens are a significant threat to public health worldwide. However, the primary carrier of AMR genes, particularly against last-resort antibiotics, is still only partially studied in Chinese hospitals. In a sentinel hospital in China, we collected 157 E. coli strains from patients between January and July 2021. One blaNDM-1-, nine blaNDM-5-, and one mcr-1-positive E. coli recovered from inpatients were identified as resistant to meropenem and colistin. There are 37 virulence genes discovered in the 11 strains, including astA in strain EC21Z-147 (O128: H4), which belongs to the enteroaggregative E. coli (EAEC). The blaNDM gene is distributed into distinct ST types, including ST48, ST616, ST410, ST711, and ST2003, while the mcr-1 gene was identified in ST117. The conjugative plasmids IncX3, IncI1-I, and IncI2 mediated the blaNDM-5 and mcr-1 genes detected among inpatients. Notably, the youngest age at which mcr-1-positive E. coli has been reported was at one day old, in a child in which the strain is closely related to strains with animal origins. Hospitals are major environments for the spread and dissemination of critical virulence and AMR genes, which requires active monitoring systems at the genome level to surveil the spread of virulence and AMR.

[Investigation of Paeonia sinjiangensis resources using remote sensing and expert knowledge].

OBJECTIVE: To study the effectiveness and feasibility of remote sensing technology in the rare species of wild plant resources. METHOD: The mechanism and characteristics of Paeonia sinjiangensis were analyzed to find the possibility of extracting from TM imagery. An expert system has been used with Landsat Thematic Mapper data to derive P. sinjiangensis. Then logical decision rules were used with the various datasets to assign values. RESULT: The land for P. sinjiangensis possible growth were mapped and accuracy tested was approving. CONCLUSION: The results suggest that the remote sensing expert interpretation system using satellite imagery and ancillary data will be feasible for research of rare wild medicinal plants distribution.

HLA-A2-restricted human CD8(+) cytotoxic T lymphocyte responses to a novel epitope in vaccinia virus that is conserved among orthopox viruses.

Classical major histocompatibility complex class I-restricted CD8(+) cytotoxic T lymphocytes (CTLs) play an important role in protective immunity against infection with smallpox virus. The identification of target antigens is crucial for defining the role played by CD8(+) CTL responses in host resistance to smallpox and for the design of vaccines that produce effective cell-based responses. We report the identification of a novel human leukocyte antigen-A*0201-restricted epitope (J8R(11-19)) within A55R of vaccinia virus (VV) that is conserved in J8R of smallpox virus variola major. The J8R(11-19)-specific CTL line and CTL clone exerted physiologically relevant functions as they recognized VV-infected lymphoblastoid JY cells or autologous B lymphoblastoid cell lines, and the cytolytic activity was accompanied by the production of interferon- gamma , tumor necrosis factor- alpha , and interleukin-2. The CTL response was detected in individuals who had been vaccinated >30 years ago or had recently received a booster of current smallpox vaccine (Dryvax) but not in VV-naive donors.

HLA-A2-restricted CD8+-cytotoxic-T-cell responses to novel epitopes in Mycobacterium tuberculosis superoxide dismutase, alanine dehydrogenase, and glutamine synthetase.

Major histocompatibility complex class I-restricted CD8(+) cytotoxic T lymphocytes (CTL) are implicated in protective Th1 immunity to Mycobacterium tuberculosis infection. We report the identification of three novel HLA-A*0201-restricted CTL epitopes within mycobacterial superoxide dismutase (SodA), L-alanine dehydrogenase (AlaDH), and L-glutamine synthetase (GlnS) proteins.

Soluble nonclassical HLA generated by the metalloproteinase pathway.

Soluble human leukocyte antigens (HLA-A, -B, and -C) proteins can be generated by a membrane-bound metalloproteinase (MPase). The MPase-mediated pathway produces soluble nonconformed HLA proteins susceptible to further degradation, and also HLA proteins with high affinity peptides stable at physiologic temperatures. Accessibility of classical HLA to the MPase cleavage inversely correlates with stability of heavy chain (HC) interactions with beta2-microglobulin (beta(2)m). Whether a MPase is involved in release of soluble nonclassical HLA or CD1 proteins is unknown. We have investigated this question with transfectants expressing full-length HLA proteins. Native surface HLA-E and -G complexes, similar to HLA-A2, were unstable at low pH and dissociated giving rise to beta(2)m-free HC. Furthermore, HLA-E and -G proteins, similar to HLA-A2, were readily released from cell surface into supernatants as soluble 37-kilodalton beta(2)m-free HC. However, the stability of surface CD1d complexes was not affected by pH changes and no soluble CD1d was detected. Because beta(2)m-free CD1d HC were expressed on cells, the lack of cleaved soluble products cannot be explained by high stability of native complexes. Instead, absence of a CD1d-specific MPase in these cells or its impaired interactions with substrate HC may be responsible.