Antimicrobial Resistance and Microbial Ecology Group, School of Medicine, University of Galway, Galway, Ireland.
Centre for One Health, Ryan Institute, University of Galway, Galway, Ireland.
mBio. 2024 Apr 10;15(4):e0018124. doi: 10.1128/mbio.00181-24. Epub 2024 Mar 13.
A comprehensive microbial surveillance was conducted at NASA's Mars 2020 spacecraft assembly facility (SAF), where whole-genome sequencing (WGS) of 110 bacterial strains was performed. One isolate, designated 179-BFC-A-HS, exhibited less than 80% average nucleotide identity (ANI) to known species, suggesting a novel organism. This strain demonstrated high-level resistance [minimum inhibitory concentration (MIC) >256 mg/L] to third-generation cephalosporins, including ceftazidime, cefpodoxime, combination ceftazidime/avibactam, and the fourth-generation cephalosporin cefepime. The results of a comparative genomic analysis revealed that 179-BFC-A-HS is most closely related to 5B73C sharing an ANI of 78.7% and a digital DNA-DNA hybridization (dDDH) value of 23.5%, while their 16S rRNA gene sequences shared 97.7% nucleotide identity. Based on these results and the recent recognition that the genus is polyphyletic, strain 179-BFC-A-HS is proposed as a novel species of a novel genus, gen. nov., sp. nov (type strain 179-BFC-A-HS = DSM 115946 = NRRL B-65666), and its closest neighbor, , is proposed to be reassigned to this genus as comb. nov. (type strain 5B73C = DSM 21623 = JCM 21758 = KCTC 13935). It was also necessary to reclassify its second closest neighbor as a member of a novel genus , reflecting its phylogenetic position relative to the genus , for which we propose comb. nov. (type strain CC-YMP-6 = DSM 22952 = CCM 7714). Within ( = 64), exhibited 11 antibiotic resistance genes (ARG), while encoded for 3, lacking any known β-lactamases, suggesting resistance from variant penicillin-binding proteins, disrupting cephalosporin efficacy. was highly resistant to azithromycin (MIC >64 mg/L) yet susceptible to cephalosporins and penicillins.
The significance of this research extends to understanding microbial survival and adaptation in oligotrophic environments, such as those found in SAF. Whole-genome sequencing of several strains isolated from Mars 2020 mission assembly cleanroom facilities, including the discovery of the novel species , highlights the resilience and antimicrobial resistance (AMR) in clinically relevant antibiotic classes of microbes in nutrient-scarce settings. The study also redefines the taxonomic classifications within the family, aligning genetic identities with phylogenetic data. Investigating ARG and virulence factors (VF) across these strains illuminates the microbial capability for resistance under resource-limited conditions while emphasizing the role of human-associated VF in microbial survival, informing sterilization practices and microbial management in similar oligotrophic settings beyond spacecraft assembly cleanrooms such as pharmaceutical and medical industry cleanrooms.
在 NASA 的火星 2020 航天器装配设施（SAF）进行了全面的微生物监测，对 110 株细菌进行了全基因组测序（WGS）。一个分离株，命名为 179-BFC-A-HS，与已知物种的平均核苷酸同一性（ANI）低于 80%，表明这是一种新的生物体。该菌株对第三代头孢菌素（包括头孢他啶、头孢泊肟、头孢他啶/阿维巴坦组合和第四代头孢菌素头孢吡肟）表现出高水平的耐药性[最小抑菌浓度（MIC）>256mg/L]。比较基因组分析的结果表明，179-BFC-A-HS 与 5B73C 最为密切相关，ANI 为 78.7%，数字 DNA-DNA 杂交（dDDH）值为 23.5%，而它们的 16S rRNA 基因序列具有 97.7%的核苷酸同一性。基于这些结果以及最近认识到属是多系的，菌株 179-BFC-A-HS 被提议为一个新属的新型物种，属。新型，sp。nov（模式株 179-BFC-A-HS=DSM 115946=NRRL B-65666），其最近的亲缘种 被提议归入该属，属。新型（模式株 5B73C=DSM 21623=JCM 21758=KCTC 13935）。也有必要将其第二近亲 重新分类为一个新属的成员，反映了其相对于属的系统发育位置，我们建议属。新型（模式株 CC-YMP-6=DSM 22952=CCM 7714）。在 （=64）中，发现了 11 种抗生素耐药基因（ARG），而 只编码了 3 种，没有发现任何已知的β-内酰胺酶，这表明耐药性来自变异的青霉素结合蛋白，破坏了头孢菌素的疗效。对阿奇霉素（MIC>64mg/L）高度耐药，但对头孢菌素和青霉素敏感。
这项研究的意义在于了解微生物在贫营养环境中的生存和适应能力，例如在 SAF 中发现的环境。对来自火星 2020 任务装配清洁室设施的几株菌株进行全基因组测序，包括发现新型物种 ，突出了在营养匮乏环境中临床相关抗生素类别的微生物的抗药性（AMR）和抗生素耐药性。该研究还重新定义了 家族内的分类学分类，将遗传身份与系统发育数据对齐。对这些菌株的 ARG 和毒力因子（VF）进行研究，揭示了微生物在资源有限条件下的耐药能力，同时强调了人类相关 VF 在微生物生存中的作用，为类似的贫营养环境中的灭菌实践和微生物管理提供了信息，这些环境不仅限于航天器装配清洁室，还包括制药和医疗行业清洁室。
