Liang Hongxia, de Haan William P, Cerdà-Domènech Marc, Méndez Javier, Lucena Francisco, García-Aljaro Cristina, Sanchez-Vidal Anna, Ballesté Elisenda
Departament de Genètica, Microbiologia I Estadística, Facultat de Biologia, Universitat de Barcelona, Diagonal 643, E-08028, Barcelona, Spain; College of Resources and Environment, University of Chinese Academy of Sciences, 100049, Beijing, China.
GRC Geociències Marines, Departament de Dinàmica de La Terra I de L'Oceà, Facultat de Ciències de La Terra, Universitat de Barcelona, E-08028, Barcelona, Spain.
Environ Pollut. 2023 Feb 15;319:120983. doi: 10.1016/j.envpol.2022.120983. Epub 2022 Dec 31.
Plastics have been proposed as vectors of bacteria as they act as a substrate for biofilms. In this study, we evaluated the abundance of faecal and marine bacteria and antibiotic resistance genes (ARGs) from biofilms adhered to marine plastics. Floating plastics and plastics from sediments were collected in coastal areas impacted by human faecal pollution in the northwestern Mediterranean Sea. Culture and/or molecular methods were used to quantify faecal indicators (E. coli, Enterococci and crAssphage), and the ARGs sulI, tetW and bla and the 16S rRNA were detected by qPCR assays. Pseudomonas and Vibrio species and heterotrophic marine bacteria were also analysed via culture-based methods. Results showed that, plastic particles covered by bacterial biofilms, primarily consisted of marine bacteria including Vibrio spp. Some floating plastics had a low concentration of viable E. coli and Enterococci (42% and 67% of the plastics respectively). Considering the median area of the plastics, we detected an average of 68 cfu E. coli per item, while a higher concentration of E. coli was detected on individual plastic items, when compared with 100 ml of the surrounding water. Using qPCR, we quantified higher values of faecal indicators which included inactive and dead microorganisms, detecting up to 2.6 × 10 gc mm. The ARGs were detected in 67-88% of the floating plastics and in 29-57% of the sediment plastics with a concentration of up to 6.7 × 10 gc mm. Furthermore, enrichment of these genes was observed in biofilms compared with the surrounding water. These results show that floating plastics act as a conduit for both the attachment and transport of faecal microorganisms. In contrast, low presence of faecal indicators was detected in plastic from seafloor sediments. Therefore, although in low concentrations, faecal bacteria, and potential pathogens, were identified in marine plastics, further suggesting plastics act as a reservoir of pathogens and ARGs.
由于塑料可作为生物膜的基质，因此有人提出塑料是细菌的载体。在本研究中，我们评估了附着在海洋塑料上的生物膜中粪便细菌和海洋细菌的丰度以及抗生素抗性基因（ARG）。在受地中海西北部人类粪便污染影响的沿海地区收集了漂浮塑料和沉积物中的塑料。采用培养和/或分子方法对粪便指示菌（大肠杆菌、肠球菌和crAssphage）进行定量，并通过qPCR检测ARG sulI、tetW和bla以及16S rRNA。还通过基于培养的方法分析了假单胞菌属和弧菌属以及海洋异养细菌。结果表明，被细菌生物膜覆盖的塑料颗粒主要由包括弧菌属在内的海洋细菌组成。一些漂浮塑料中活的大肠杆菌和肠球菌浓度较低（分别占塑料的42%和67%）。考虑到塑料的中位面积，我们检测到每件塑料平均有68 cfu大肠杆菌，而与100 ml周围海水相比，单个塑料物品上检测到的大肠杆菌浓度更高。使用qPCR，我们对包括无活性和死亡微生物在内的粪便指示菌进行了更高值的定量，检测到高达2.6×10 gc mm。在67 - 88%的漂浮塑料和29 - 57%的沉积物塑料中检测到ARG，浓度高达6.7×10 gc mm。此外，与周围海水相比，在生物膜中观察到这些基因的富集。这些结果表明，漂浮塑料是粪便微生物附着和运输的管道。相比之下，在海底沉积物中的塑料中检测到的粪便指示菌较少。因此，尽管在海洋塑料中发现了低浓度的粪便细菌和潜在病原体，但进一步表明塑料是病原体和ARG的储存库。
