The antibiotic resistance and risk heterogeneity between urban and rural rivers in a pharmaceutical industry dominated city in China: The importance of social-economic factors.

Rivers are important environmental sources of human exposure to antibiotic resistance. Many factors can change antibiotic resistance in rivers, including bacterial communities, human activities, and environmental factors. However, the systematic comparison of the differences in antibiotics resistance and risks between urban rivers (URs) and rural rivers (RRs) in a pharmaceutical industry dominated city is still rare. In this study, Shijiazhuang City (China) was selected as an example to compare the differences in antibiotics resistance and risks between URs and RRs. The results showed higher concentrations of total quinolones (QNs) antibiotics in both water and sediment samples collected from URs than those from RRs. The subtypes and abundances of antibiotic resistance genes (ARGs) in URs were significantly higher than those in RRs, and most emerging ARGs (including OXA-type, GES-type, MCR-type, and tet(X)) were only detected in URs. The ARGs were mainly influenced by QNs in URs and social-economic factors (SEs) in RRs. The composition of the bacterial community was significantly different between URs and RRs. The abundance of antibiotic-resistant pathogenic bacteria (ARPBs) and virulence factors (VFs) were higher in URs than those in RRs. Therein, 371 and 326 pathogen types were detected in URs and RRs, respectively. Most emerging ARGs showed a significantly positive correlation with priority ARPBs. Variance partitioning analysis revealed that SEs were the main driving factors of ARGs (80 %) and microbial communities (92 %) both in URs and RRs. Structural equation models indicated that antibiotics (QNs) and microbial communities were the most direct influence of ARGs in URs and RRs, respectively. The cumulative resistance risk of QNs was high in URs, but relatively low in RRs. Enrofloxacin and flumequine posed the highest risk in water and sediment, respectively. This study could help us to better manage and control the risk of antibiotic resistance in different rivers.

[Distribution Coefficient of QNs in Urban Typical Water and Its Main Environmental Influencing Factors].

Sediment is the main storage medium of antibiotics in a water environment, and a growing body of research has focused on the distribution behavior of antibiotics in water-sediment. However, most of the previous studies were based on laboratory simulation, and less attention was paid to the distribution behavior of antibiotics in a natural water environment and its correlation with environmental factors. Thus, the surface water and sediment in Shijiazhuang were taken as the research object for this study. The temporal and spatial distribution characteristics of quinolone (QNs) antibiotics in Shijiazhuang water were analyzed by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS), calculating the distribution coefficients of quinolone (QNs) antibiotics in water and sediment, and confirming the main environmental factors influencing the distribution coefficient in natural water. The results showed that:① the content of ΣQNs in water and sediment ranged from 8.0 to 4.4×103 ng·L-1 and 16 to 2.2×103 ng·g-1 in Shijiazhuang water, whereas the primary QNs in water and sediment were enrofloxacin (ENR) and ofloxacin (OFL), respectively. ② The total concentrations of ΣQNs in Shijiazhuang water showed a tendency of being higher in December (1.0×104 ng·L-1) than in April (5.5×103 ng·L-1), and QNs in sediment were also higher in December (7.8×103 ng·g-1) than in April (6.2×103 ng·g-1). ③ The distribution coefficient of QNs in Shijiazhuang water varied from 34 to 2.9×105 L·kg-1 and showed a trend of being greater in December than in April. ④ The results of correlation analysis showed that total nitrogen (TN), nitrate nitrogen (NO3--N), nitrite nitrogen (NO2--N), and ammonia nitrogen (NH4+-N) were significantly correlated with most distribution coefficients of QNs[OFL, norfloxacin (NOR), ENR, difloxacin (DIF), and oxolinic acid (OXO)], whereas temperature (T), total organic carbon (TOC), and total dissolved solids (TDS) were significantly correlated with individual distribution coefficients of QNs[marbofloxacin (MAR) and DIF]. Therefore, the eutrophication level of water affects the distribution behavior of antibiotics in water-sediment.

[Ecological Risk Assessment of Quinolones Antibiotics and the Correlation Analysis Between QNs and Physical-Chemical Parameters in Groundwater, Shijiazhuang City].

Most studies on antibiotics in groundwater have focused on pollution characteristics, whereas less attention has been paid to the ecological risks of antibiotics and the correlation to environmental parameters. In this study, the groundwater in Shijiazhuang City was selected as the research area. Through high performance liquid chromatography-tandem mass spectrometry (HPLC-MS), the concentration of quinolones (QNs) in the groundwater was analyzed. Correlation analysis was conducted between QNs concentrations and physical-chemical parameters. The results showed that:① the detection frequency of flumequine (FLU) was the highest (100%), followed by enoxacin (ENO) (80.0%) and ciprofloxacin (CIP) (75.0%). ② The concentration of QNs ranged from 3.02 to 98.5 ng·L-1; in terms of spatial distribution, the highest concentration of QNs appeared at S4 (98.5 ng·L-1), whereas the lowest concentration was exhibited at S19 (3.02 ng·L-1). ③ Temperature (T), chemical oxygen demand (COD), total dissolved solids (TDS), total number of colonies (BCTC), and pH were significantly correlated with QNs (P<0.01 or P<0.05) based on correlation analysis. ④ For the spatial distribution of ecological risk, the results showed that the ecological risk at S4 was high, whereas the risks for other sites were low. For the type of QNs, ciprofloxacin (CIP) was at a medium-high risk level, whereas the other QNs were at a low-risk level. Thus, in order to guarantee the ecological safety of groundwater in Shijiazhuang City, more attention should be paid to the risk management and control of antibiotics in groundwater in the future.

[Spatial Distribution of Quinolone Antibiotics and Its Correlation Relationship with Microbial Community in Soil of Shijiazhuang City].

Microbial communities are an important component of soil ecosystems. Long-term low content antibiotic pollution will affect the structure and function of microbial communities in soil. Therefore, Shijiazhuang City was selected as the study area, in which twelve sample points were set up in September 2020. These sample sites were divided into four areas (S1, S2, S3, and S4) according to spatial orientation. Ultra-high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) was applied to determine the content of typical antibiotic-quinolones (QNs) in the soil. 16S rRNA high-throughput sequencing technology was used to study the microbial community structure and diversity in the soil. The results showed that:① the total detected contents of QNs in the four areas were S3 (313.5 µg·kg-1)>S4 (65.54 µg·kg-1)>S1 (46.19 µg·kg-1)>S2 (12.63 µg·kg-1). The content of norfloxacin (NOR) was the highest (91.99 µg·kg-1), whereas the content of oxolinic acid (OXO) was the lowest (0.4486 µg·kg-1). ② For grain size, the proportion of powder (2-50 µm) was the highest (66.7%-93.2%), whereas the proportion of clay (less than 2 µm) was the lowest (2.50%-9.10%). For physical and chemical parameters, total phosphorus (TP) and ammonia nitrogen (NH4+-N) showed non-significant spatial differences, whereas nitrate nitrogen (NO3--N), nitrite nitrogen (NO2--N), and grain size showed significant spatial differences. ③ For microbial community composition, there were six dominant bacteria phyla and five dominant bacteria genera, among which Actinobacteriota (18.3%-34.6%) and Proteobacteria (13.6%-34.1%) were the dominant bacteria phyla, and Arthrobacter (3.24%-8.61%) and Nitrososphaeraceae (2.93%-9.46%) were the dominant bacteria genera. The diversity results showed the highest value in the S2 area (6.48) and the lowest value in the S3 area (5.89). ④ QNs and soil physical and chemical parameters significantly changed the structural composition of microbial communities, and OXO, NO3--N, and soil particle size affected the diversity of microbial communities. FLU, NH4+-N, NO2--N, and soil particle size affected the function of the microbial community. Therefore, it is necessary to further strengthen the risk control of antibiotics in the soil of Shijiazhuang City.

The difference of trophic magnification factors of Quinolones antibiotics (QNs) between pelagic and benthic foodwebs in a shallow lake: importance of carbon and nitrogen sources.

Feeding habitat and carbon source play critical roles in certain the trophic transfer and bioaccumulation ability of chemicals in aquatic ecosystems. However, it remains largely unknown how these factors affect the trophic magnification factors (TMFs) of antibiotics in lake ecosystem. This study compared the differences of TMFs for Quinolones (QNs) antibiotics and carbon/nitrogen sources between pelagic foodweb (PFW, 11 species) and benthic foodweb (BFW, 14 species) in Baiyangdian Lake, Northern China. δ13C showed higher values in BFW, while δ15N appeared higher values in PFW. The mean percentage of pelagic nitrogen source (PNS) was higher than benthic nitrogen source (BNS), while the mean percentages of pelagic carbon source (PCS) and benthic carbon source (BCS) were approximately equal. Relatively high concentrations of enrofloxacin (ENR), flumequine (FLU), norfloxacin (NOR), and ofloxacin (OFL) were detected, and the total concentrations of QNs were 27.73-126.4 ng/g dw in PFW, while 23.49-121.3 ng/g dw in BFW. ENR and NOR appeared trophic magnification, while FLU and OFL exhibited trophic dilution. The TMFs of these QNs in PFW were significantly higher than in BFW. The concentration of QNs in biological samples were significantly positive correlation with δ15N, while negative correlated with δ13C. The TMFs for FLU and OFL were positively correlated with PCS/PNS, while negatively correlated with BCS/BNS. The opposite was true for NOR and ENR. CAPSULE ABSTRACT: First studied the differences of TMFs for typical QNs and carbon/nitrogen sources between PFW and BFW in a shallow lake.

The key environmental influencing factors for the change of sediment bacterial community and antibiotics resistance genes in a long-term polluted lake, China.

In order to investigate the key environmental influencing factors for the change of sediment bacterial community structure (BCS) and antibiotics resistance genes (ARGs) in a long-term Quinolone antibiotics (QNs) and heavy metals (HMs) polluted lake, 16S rRNA MiSeq High-throughput Sequencing and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis methods were applied. Baiyangdian lake was subdivided into three habitats: (1) Habitat 1: greatly influenced by municipal wastewater; (2) Habitat 2: mainly impacted by aquaculture sewage and domestic wastewater; and (3) Habitat 3: with the least human activities. Through One-way ANOVA analysis, the results showed that most of QNs and HMs showed significant difference among three habitats. Both the highest richness and diversity indices of bacterial community appeared in Habitat 3. The abundance of Multidrug, Phenicol, Aminoglycoside, Teracycline, and Quinolone ARGs exhibited the highest values in Habitat 1, while the abundance of Macrolide-Lincosamide-Streptogramin (MLS), Rifamycinm, and Sulfonamide ARGs appeared the highest values in Habitat 2. The result of redundancy analysis exhibited that 68.8% and 93.8% of the change in BCS and ARGs can be explained by environmental factors, respectively. Pb (explained 37.5% (p = 0.002)) and Fleroxacin (FLE) (explained 51.3% (p = 0.026)) were the most important factors for the variation of BCS and ARGs, respectively. Therefore, the effects of antibiotics and HMs on BCS and ARGs should be simultaneously paid more attention. Furthermore, the ARGs results by PICRUSt were similar to the results by metagenomic shotgun sequencing analysis, thus the PICRUSt analysis method can be used in the future research.

[Bioaccumulation Characteristics of Quinolones (QNs) in Dominant Fish Species and Their Correlation with Environmental Factors in Baiyangdian Lake].

In recent years, quinolone antibiotics (QNs), which easily bioaccumulate in aquatic organisms, have been widely detected in lake ecosystems, and the bioaccumulation and trophic transfer behavior are obviously spatiotemporally different. In this study, the bioaccumulation and trophic transfer behavior of fourteen QNs in nine dominant fish species were studied, the correlation with environmental factors was analyzed, and the health risk of QNs was evaluated in Baiyangdian Lake. The results showed that the mass concentrations of ∑QNs in water varied from 0.7400 to 1590 ng·L-1. Furthermore, the detected frequencies of flumequine (FLU), oxolinic acid (OXO), and ofloxacin (OFL) were higher, and the average mass concentration of FLU was the highest. The content of ∑QNs in fish ranged from 17.1 to 146 ng·g-1, and the average contents of ciprofloxacin (CIP) and OFL were higher. The bioaccumulation factors (BAF) were in the range of 96.2 (BAFMAR)-489 (BAFCIP) L·kg-1, indicating the bioaccumulation of QNs was low in dominant fish species. The trophic magnification factors (TMF) of five QNs (enrofloxacin (ENR), FLU, marbofloxacin (MAR), norfloxacin (NOR), and OFL) varied from 0.714 (TMFMAR) to 1.33 (TMFENR), indicating ENR exhibited trophic magnification, while FLU, MAR, and ∑QNs exhibited trophic dilution. The results of correlation analysis between environmental parameters and BAF/TMF showed that pH, T, SD, DO, COD, TP, TN, NH4+-N, NO3--N, and PO43--P were significantly related to the bioaccumulation of QNs in fish. The results of human health risk showed that the hazard quotient (HQ) of CIP (0.0040-0.026) was significantly higher than that of other QNs (≤ 0.0050), and the hazard indices (HI) ranged from 0.0010 to 0.035, indicating a high level of health risk. Therefore, to reduce the health risk, the standard and residue limits of QNs should be set in Baiyangdian Lake.