Urinary antibiotic level of school children in Shanghai, East China, 2017-2020

Presence of antibiotics in children's urine: a silent risk beyond drinking water

This study investigated the presence of 32 antibiotic residues in drinking water, their potential association with antibiotic concentrations in children's urine samples, and anthropometric indicators. Water samples were collected from the primary water sources supplying Ilo, Peru (Pacocha and Pampa), and urine samples were analysed from children aged 2 to 10 years using liquid chromatography coupled to tandem mass spectrometry with triple quadrupole. Five antibiotics were detected in drinking water, with three of these representing a health risk due to high concentrations and risk quotients (RQ): Doxycycline (2.30), Sulfamethoxazole (1.04), and Metronidazole (25.68). Furthermore, there was no correlation between the antibiotics found in drinking water and those detected in urine samples, as the types and quantities of antibiotics differed. In urine samples, 21 antibiotics were detected in children from Pacocha and 19 from Pampa. The antibiotics and anthropometric variables did not show any significant correlation. Principal component analysis revealed that antibiotic profiles were highly similar across both areas, suggesting a shared source of contamination independent of drinking water. It is concerning that 100% of the children have at least three antibiotics in their urine, which could affect their health now and later in life.

The role of residual (veterinary) antibiotics in chemical exposome analysis: Current progress and future perspectives

Humans are exposed to a complex mixture of environmental and food-related chemicals throughout their lifetime. Exposome research intends to explore the nongenetic, that is, environmental causes of chronic disease and their interactions comprehensively. Residual antibiotics can enter the human body through therapeutics, foods of animal origin, aquatic products, or drinking water. In the last decade, significant levels of residual antibiotics in human urine have been described, demonstrating frequent exposure throughout populations. To which extent they contribute to human health risks is debated. Human biomonitoring (HBM) aims to determine and quantify concentrations of xenobiotics in human specimens and provides the toolbox to monitor exposure to diverse chemical exposures. Due to their public health implications, priority-listed xenobiotics are routinely monitored in the European Union and other countries. However, antibiotics, an important class of (food-derived) xenobiotics, are still not systematically investigated for a better and more holistic understanding in the context of exposomics. This review provides a comprehensive summary of HBM research related to antibiotics, existing liquid chromatography-mass spectrometry (LC-MS)-based analytical methods, and potential health risks caused by unintended exposure. Incorporating antibiotics into the chemical exposome framework through routine HBM using multiclass analytical methods will provide a better understanding of the toxicological or pharmacological mixture effects and, ultimately, the chemical exposome.

Impact of low-level exposure to antibiotics on bile acid homeostasis in adults: Implication for human safety thresholds

Bile acid homeostasis is critical to human health. Low-level exposure to antibiotics has been suggested to potentially disrupt bile acid homeostasis by affecting gut microbiota, but relevant data are still lacking in humans, especially for the level below human safety threshold. We conducted a cross-sectional study in 4247 Chinese adults by measuring 34 parent antibiotics and their metabolites from six common categories (i.e., tetracyclines, qinolones, macrolides, sulfonamides, phenicols, and lincosamides) and ten representative bile acids in fasting morning urine using liquid chromatography coupled to mass spectrometry. Daily exposure dose of antibiotics was estimated from urinary concentrations of parent antibiotics and their metabolites. Urinary bile acids and their ratios were used to reflect bile acid homeostasis. The estimated daily exposure doses (EDED) of five antibiotic categories with a high detection frequency (i.e., tetracyclines, qinolones, macrolides, sulfonamides, and phenicols) were significantly associated with urinary concentrations of bile acids and decreased bile acid ratios in all adults and the subset of 3898 adults with a cumulative ratio of antibiotic EDED to human safety threshold of less than one. Compared to a negative detection of antibiotics, the lowest EDED quartiles of five antibiotic categories and four individual antibiotics with a high detection frequency (i.e., ciprofloxacin, ofloxacin, trimethoprim, and florfenicol) in the adults with a positive detection of antibiotics had a decrease of bile acid ratio between 6.6% and 76.6%. Except for macrolides (1.2×102 ng/kg/day), the medians of the lowest EDED quartile of antibiotic categories and individual antibiotics ranged from 0.32 ng/kg/day to 10 ng/kg/day, which were well below human safety thresholds. These results suggested that low-level antibiotic exposure could disrupt bile acid homeostasis in adults and existing human safety thresholds may be inadequate in safeguarding against the potential adverse health effects of low-level exposure to antibiotics.

Trophic transfer of antibiotics in the benthic-pelagic coupling foodweb in a macrophyte-dominated shallow lake: The importance of pelagic-benthic coupling strength and baseline organism

In lake ecosystems, pelagic-benthic coupling strength (PBCS) is closely related to foodweb structure and pollutant transport. However, the trophic transfer of antibiotics in a benthic-pelagic coupling foodweb (BPCFW) and the manner in which PBCS influences the trophic magnification factor (TMFs) of antibiotics is still not well understood in the whole lake. Herein, the trophic transfer behavior of 12 quinolone antibiotics (QNs) in the BPCFW of Baiyangdian Lake were studied during the period of 2018-2019. It was revealed that 24 dominant species were contained in the BPCFW, and the trophic level was 0.42-2.94. Seven QNs were detected in organisms, the detection frequencies of ofloxacin (OFL), flumequine (FLU), norfloxacin (NOR), and enrofloxacin (ENR) were higher than other QNs. The ∑QN concentration in all species was 11.3-321 ng/g dw. The TMFs for ENR and NOR were trophic magnification, while for FLU/OFL it was trophic dilution. The PBCS showed spatial-temporal variation, with a range of 0.6977-0.7910. The TMFs of ENR, FLU, and OFL were significantly positively correlated with PBCS. Phytoplankton and macrophyte biomasses showed indirect impact on the TMFs of QNs by directly influencing the PBCS. Therefore, the PBCS was the direct influencing factor for the TMFs of chemicals.

Urinary antibiotics concentrations, their related affecting factors and infant growth in the first 6 months of life: A prospective cohort study

Antibiotic exposure even in low-dose could have potential adverse health effects, especially during early life. There is a lack of data on antibiotic burdens in early infancy. We aim to assess antibiotic exposure in infants from birth to 6 months of age, their related affecting factors and the association between antibiotic exposure and infancy growth. Urine samples were collected at ages of 3 days, 42 days, 3 months and 6 months from 197 term-born Chinese infants. A total of 33 representative antibiotics were measured by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Urinary antibiotics were detectable in 69.4%, 63.2%, 75.0% and 84.3% of infants at ages of 3 days, 42 days, 3 and 6 months, respectively. The dominant antibiotic categories detected were: Preferred as Veterinary Antibiotics (PVAs), Human Antibiotics (HAs), and Veterinary Antibiotics (VAs). The detectable rates were 30.6%, 45.8%, 58.9%, and 81.4% for PVAs, 34.1%, 20.8%, 28.6%, and 45.1% for HAs, and 36.5%, 12.5%, 6.3%, and 5.9% for VAs, at age 3 days, 42 days, 3 and 6 months, respectively. Urinary concentrations of HAs and preferred as human antibiotics (PHAs) in newborns at age 3 days were not associated with maternal intrapartum antibiotic prophylaxis. Similarly, no associations were observed between urinary antibiotics concentration and antibiotics use in infants at age 42 days or 6 months. The numbers and concentrations of urine detectable antibiotics were similar between infants with exclusive breastfeeding and infants fed with formula or mixed-feeding at all ages of 42 days, 3 and 6 months. At age of 42 days, infants in the low tertile of total antibiotics concentration or with one antibiotic detected had higher weight-for-length Z score and greater head circumference, compared to infants with no antibiotics detected. No associations were found between urinary antibiotics and any of the infant anthropometric measures at age 6 months. In conclusion, urinary antibiotics were detectable in most infants during the first 6 months of life, and PVAs, HAs and VAs were the most commonly detected antibiotics. This suggested the possibility of a foods-originated antibiotics exposure in children. No strong nor consistent associations were found between urinary antibiotic concentration and infant growth at the first six months of life. Still, attention is needed on the adverse health effect of early life exposure to antibiotics in future studies.

Occurrence, distribution, and risk assessment of quinolone antibiotics in municipal sewage sludges throughout China

A nationwide study of the occurrence, distribution, potential drivers, and ecological risks of 24 quinolone antibiotics (QNs) in 74 Chinese sludge samples from 48 wastewater treatment plants (WWTPs) was conducted. In domestic sludge, the ∑QNs concentrations were <LOD to 21,925.10 ug/kg (mean: 4808.67 ug/kg), and ofloxacin had the highest concentration (<LOD-11,138.52 ug/kg), and detection frequency (98.48%). Of four generations QNs, the levels showed the following order: 2nd-generation QNs > 3rd-generation QNs > 4th-generation QNs > 1st-generation QNs. Meanwhile, abundant veterinary and human/veterinary quinolones (<LOD-2606.96 and <LOD-12,643.47 ug/kg, respectively) were detected in municipal sludge. Interestingly, the relatively low levels of veterinary quinolones (<LOD-299.21 ug/kg) were also found in industrial sludge (the relevant WWTPs receiving ≤ 10% domestic wastewater, without other direct entry of antibiotics). The correlation analysis demonstrated QNs contamination was negatively influenced by the air temperature of sampling days. The positive correlation between moxifloxacin contents and regional economy possibly suggested local regions with relatively high economic levels face a more difficult situation of QNs antibacterial activity. Environmental risk assessment indicated ofloxacin, ciprofloxacin, and moxifloxacin posed high ecological risks to the domestic sludge. This work delineates a valuable nationwide QNs contamination profile to support their safe use and control in China.

Antibiotic residues of drinking-water and its human exposure risk assessment in rural Eastern China

Trace levels of antibiotics were frequently found in drinking-water, leading a growing concern that drinking-water is an important exposure source to antibiotics in humans. In this study, we investigated antibiotics in tap water and well water in two rural residential areas in Eastern China to assess the related human health exposure risks in drinking-water. Twenty-seven antibiotics were analyzed using ultra performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UPLC-MS/MS). The average daily dose (ADD) and the health risk quotient (HRQ) for exposure to antibiotics in humans were evaluated using 10000 times of Monte Carlo simulations. Ten antibiotics were detected in drinking-water samples, with the maximum concentrations of antibiotic mixture of 8.29 ng/L in tap water and 2.95 ng/L in well water, respectively. Macrolides and sulfonamides were the predominant contaminants and showed the seasonality. Azithromycin had the highest detection frequencies (79.71-100%), followed by roxithromycin (25.71-100%) and erythromycin (21.43-86.96%). The estimated ADD and HRQ for human exposure to antibiotic mixture through drinking-water was less than 0.01 μg/kg/day and 0.01, respectively, which varied over sites, water types, seasons and sex. Ingestion route was more important than dermal contact route (10-6 to 10-4 μg/kg/day magnitude vs. 10-11 to 10-8 μg/kg/day magnitude). Macrolides also contributed mainly to health exposure risks to antibiotics through drinking-water, whose HRQ accounted for 46% to 67% of the total HRQs. Although the individual antibiotic and their combined effects contributed to acceptable health risks for human, the long-term exposure patterns to low-dose antibiotics in drinking-water should not be ignored.

Exposure of Tibetan pregnant women to antibiotics in China: A biomonitoring-based study

Tibetan people are one Chinese ethnic minority living in Qinghai-Tibet Plateau with an average altitude of more than 4500 m. High altitude could cause a different antibiotic exposure, but relevant information is limited in Tibetan people. We investigated 476 Tibetan pregnant women in Lhasa, Tibet in 2021 and measured 30 antibiotics from five categories in urine, including 13 veterinary antibiotics (VAs), five human antibiotics (HAs), and 12 human/veterinary antibiotics (H/VAs). Food consumption was investigated by a brief food frequency questionnaire. Health risk was assessed by hazard quotient (HQ) and hazard index (HI) based on acceptable daily intakes (ADIs). All antibiotics were overall detected in 34.7% of urine samples with the 75th percentile concentration of 0.19 ng/mL (0.35 μg/g creatinine). HAs, VAs, and H/VAs were respectively detected in 5.3%, 13.0%, and 25.0% of urine samples, with the 95th percentiles of 0.01 ng/mL (0.01 μg/g creatinine), 0.50 ng/mL (0.99 μg/g creatinine), and 3.58 ng/mL (5.02 μg/g creatinine), respectively. Maternal age, smoking of family members, and housework time were associated with detection frequencies of HAs, VAs, or sum of all antibiotics. Pregnant women with a more frequent consumption of fresh milk, egg, yoghourt, poultry meat, and fish had a higher detection frequency of VAs or H/VAs. Only ciprofloxacin and tetracycline had a HQ of larger than one based on microbiological effect in 1.26% and 0.21% of pregnant women, respectively and a HI of larger than one was found in 1.47% of pregnant women. The findings suggested that there was an evident antibiotic exposure from various sources in Tibetan pregnant women with some basic characteristics of pregnant women as potential predictors and several animal-derived food items were important sources of exposure to antibiotic with a fraction of pregnant women in the health risk related to microbiological disruption of gut microbiota.

Urinary Antibiotics and Dietary Determinants in Adults in Xinjiang, West China

The Xinjiang autonomous region, located in west China, has a unique ethnic structure and a well-developed livestock industry. People in this region have a high risk of exposure to antibiotics, but the exposure level to antibiotics in relation to dietary determinants is unknown. In this study, 18 antibiotics, including four human antibiotics (HAs), four veterinary antibiotics (VAs), and 10 preferred veterinary antibiotics (PVAs) were detected in the urine of approximately half of the 873 adults in Xinjiang, including Han Chinese (24.6%), Hui (25.1%), Uighur (24.6%), and Kazakh (25.7%). Logistic regression was used to analyze the association between antibiotic exposure levels and adult diet and water intake. The detection percentage of antibiotics in the urine of adults in Xinjiang ranged from 0.1% to 30.1%, with a total detection percentage of all antibiotics of 49.8%. HAs, VAs and PVAs were detected in 12.3%, 10.3%, and 40.5%, respectively. Fluoroquinolones were the antibiotics with the highest detection percentage (30.1%) and tetracyclines were the antibiotics with the highest detected concentration (17 ng/mL). Adults who regularly ate pork, consumed fruit daily, and did not prefer a plant-based diet were associated with thiamphenicol, norfloxacin, and fluoroquinolones, respectively. These results indicated that adults in the Xinjiang autonomous region were extensively exposed to multiple antibiotics, and some types of food were potential sources of exposure. Special attention should be paid to the health effects of antibiotic exposure in humans in the future.

Association between fluoroquinolone exposure and children's growth and development: A multisite biomonitoring-based study in northern China

BACKGROUND

Although animal experiments found that antibiotic exposure during early life increased adiposity, limited human epidemiological evidence is available for the effects of veterinary antibiotic exposure on children's growth and development.

OBJECTIVE

This study was conducted to examine the body burden of fluoroquinolones in northern Chinese children and assess its association with growth and development.

METHODS

After recruiting 233 children aged 0-15 years from 12 different sites in northern China in 2020, we measured urinary concentrations of 5 respective fluoroquinolones (fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) by high performance liquid chromatography. Categories of children's growth and development were identified based on the Z score of body mass index. The health risks of individual and combined antibiotic exposure were estimated by the hazard quotient (HQ) and hazard index (HI), respectively. The association between children's growth and development with antibiotic concentrations was evaluated via multiple logistic regression analysis.

RESULTS

In total, 4 antibiotics, fleroxacin, ofloxacin, ciprofloxacin, and enrofloxacin, were found in urine samples of northern Chinese children at an overall frequency of 57.08%. Due to diet and economic differences, antibiotic concentrations in urine samples differed by study area, and the highest concentrations were found in Tianjin, Henan, and Beijing. The percentage of the participants with HQ > 1 caused by ciprofloxacin exposure was 20.61%, and the HI values in 23.18% of samples exceeded 1, suggesting potential health risks. The odds ratio (95% confidence interval) of overweight or obesity risk of tertile 2 of enrofloxacin was 3.01 (1.12, 8.11), indicating an increase in overweight or obesity risk for children with middle-concentration enrofloxacin exposure.

CONCLUSION

This is the first study to show a positive association of enrofloxacin internal exposure with overweight or obesity risk in children, demonstrating that more attention should be given to the usage and disposal of fluoroquinolones to safeguard children's health.