發(fā)布者：抗性基因網(wǎng) 時間：2023-06-14 瀏覽量：701
摘要
出身背景
氣單胞菌是廣泛分布于生態(tài)系統(tǒng)中的機(jī)會性病原體。已知它們能夠獲得抗生素抗性基因，包括編碼抗最后一種抗生素的蛋白質(zhì)的基因，如tmexCD toprJ、mcr和碳青霉烯酶基因。我們研究了從人類、動物和水樣中，特別是從中國醫(yī)院廢水中采集的tmexCD toprJ陽性氣單胞菌的基因組和表型特征。
方法
從活體動物、肉類、水和人類身上采集樣本。在選擇性培養(yǎng)基中分離這些樣品中的氣單胞菌菌株。采用肉湯微量稀釋法檢測了所有氣單胞菌的耐藥性。通過聚合酶鏈?zhǔn)椒磻?yīng)（PCR）證實了tmexD-toprJ的存在。對所有tmexCD toprJ陽性（n=36）和選定的tmexCD toprJ陰性（n=18）氣單胞菌菌株進(jìn)行全基因組測序。通過生物信息學(xué)分析確定了抗微生物基因的攜帶、tmexD-toprJ的遺傳環(huán)境以及tmexD-toprJ陽性氣單胞菌的遺傳多樣性。利用Harvest Suite建立了氣單胞菌的系統(tǒng)發(fā)育樹。
調(diào)查結(jié)果
在從不同來源分離的636株氣單胞菌中，36株對tmexD-toprJ呈陽性，其中魚類中tmexD-toprJ的患病率最高（8.8%，95%CI%3.6–17.2%），其次是醫(yī)院廢水（6.5%，95%CI%4.3–9.3%），河水（2.0%，0.1-10.9）和鴨子（1.2%，95%CI%，3.6-17.2%）。所有tmexCD toprJ陽性氣單胞菌都攜帶多種抗微生物耐藥性基因，并對不同種類的抗生素表現(xiàn)出耐藥性。在21株菌株中鑒定出tmexD-toprJ、mcr和blaKPC-2共存。tmexCD toprJ陽性氣單胞菌菌株具有遺傳多樣性，屬于四個不同的物種，可分為三個主要譜系。tmexD-toprJ基因簇主要位于氣單胞菌屬的染色體（35/36）上，只有一株菌株攜帶質(zhì)粒攜帶的tmexD-toprJ簇。tmexCD toprJ基因與七種不同類型的遺傳環(huán)境有關(guān)，每種遺傳環(huán)境都攜帶不同類型的可移動元件，這些元件可能負(fù)責(zé)介導(dǎo)該基因簇的傳播。
Abstract
Background
Aeromonas species are opportunistic pathogens distributed widely in the ecosystem. They are known to be capable of acquiring antibiotic resistance genes, including those encoding proteins against last-line antibiotics, such as the tmexCD-toprJ, mcr and carbapenemase genes. We investigated the genomic and phenotypic characteristics of tmexCD-toprJ-positive Aeromonas strains collected from human, animals, and water samples, particularly those from hospital wastewater in China.
Methods
Samples were collected from living animals, meat, water and human. Aeromonas strains in these samples were isolated in selective media. Antimicrobial resistance profiles of all Aeromonas strains were tested by the broth microdilution method. The presence of tmexCD-toprJ was verified by polymerase chain reaction (PCR). All tmexCD-toprJ-positive (n = 36) and selected tmexCD-toprJ-negative (n = 18) Aeromonas strains were subjected to whole genome sequencing. Carriage of antimicrobial resistance genes, the genetic environment of tmexCD-toprJ and genetic diversity of tmexCD-toprJ-positive Aeromonas strains were determined by bioinformatics analysis. Phylogenetic tree of the Aeromonas strains was built by using the Harvest Suite.
Findings
Among the 636 Aeromonas strains isolated from different sources, 36 were positive for tmexCD-toprJ, with the highest prevalence of tmexCD-toprJ being found in fishes (8.8%, 95 CI% 3.6–17.2%), followed by hospital wastewater (6.5%, 95 CI% 4.3–9.3%), river water (2.0%, 0.1–10.9) and duck (1.2%, 95 CI% 3.6–17.2%). All tmexCD-toprJ-positive Aeromonas strains carried multiple antimicrobial resistance genes and exhibited resistance to different classes of antibiotics. Co-existence of tmexCD-toprJ, mcr and blaKPC-2 were identified in 21 strains. The tmexCD-toprJ-positive Aeromonas strains were genetically diverse and found to belong to four different species that could be clustered into three major lineages. The tmexCD-toprJ gene clusters were predominantly located in the chromosome (35/36) of Aeromonas spp., with only one strain carrying the plasmid-borne tmexCD-toprJ cluster. The tmexCD-toprJ genes were associated with seven different types of genetic environments, each of which carried distinct types of mobile elements that may be responsible for mediating transmission of this gene cluster.
https://www.sciencedirect.com/science/article/abs/pii/S1368764623000080