Antibiotic body burden of elderly Chinese population and health risk assessment: A human biomonitoring-based study

Antibiotic body burden of elderly Chinese population and health risk assessment: A human biomonitoring-based study

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Journal Pre-proof Antibiotic body burden of Chinese elderly population and health risk assessment: A biomonitoring-based study Yitian Zhu, Kaiyong Liu, Jingjing Zhang, Xinji Liu, Linsheng Yang, Rong Wei, Sufang Wang, Dongmei Zhang, Shaoyu Xie, Fangbiao Tao PII:

S0269-7491(19)33487-6

DOI:

https://doi.org/10.1016/j.envpol.2019.113311

Reference:

ENPO 113311

To appear in:

Environmental Pollution

Received Date: 30 June 2019 Revised Date:

24 September 2019

Accepted Date: 25 September 2019

Please cite this article as: Zhu, Y., Liu, K., Zhang, J., Liu, X., Yang, L., Wei, R., Wang, S., Zhang, D., Xie, S., Tao, F., Antibiotic body burden of Chinese elderly population and health risk assessment: A biomonitoring-based study, Environmental Pollution (2019), doi: https://doi.org/10.1016/ j.envpol.2019.113311. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.

22 20

Clinical Use Self-Medication

19.0

18 16.5

Antibiotics

Elderly

Urine

Population proportion (%)

16 14 12.5 11.5

12 9.6

10 8

11.2

7.0

6.8 5.9

6 4

Animal-derived Food Drinking Water

2 0
Estimated daily intake (µg/kg/day)

1

1

Antibiotic body burden of Chinese elderly population and health

2

risk assessment: a biomonitoring-based study

3

Yitian Zhu1^, Kaiyong Liu1,5^, Jingjing Zhang1, Xinji Liu1, Linsheng Yang2, Rong Wei1, Sufang Wang1,

4

Dongmei Zhang3, Shaoyu Xie4, Fangbiao Tao6*

5 6

1. Department of Nutrition and Food Hygiene, School of Public Health, Anhui Medical University,

7

81 Meishan Road, Hefei, Anhui 230032, PR China.

8

2. Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical

9

University, 81 Meishan Road, Hefei, Anhui 230032, PR China.

10

3. School of Health Management, Anhui Medical University, Hefei, Anhui 230032, PR China.

11

4. Lu’an Center of Disease Control and Prevention, Lu’an, Anhui, 237000, PR China

12

5. Department of Microbiology and Immunology, University of Michigan Medical School, Ann

13

Arbor, MI 48109, USA.

14

6. Anhui Provincial Key Laboratory of Population Health and Aristogenics, 81 Meishan Road,

15

Hefei, Anhui 230032, PR China.

16 17

^

18

*Corresponding author: Email: [email protected]. Anhui Provincial Key Laboratory of

19

Population Health and Aristogenics, 81 Meishan Road, Hefei, Anhui 230032, PR China.

These authors contributed equally to this work.

20 21 22 1

23

Abstract

24

Limited biomonitoring studies have demonstrated an extensive exposure

25

of different populations to antibiotics, but antibiotic body burden and the

26

potential health risks in the Chinese elderly population remains unclear.

27

In the present study, we investigated 990 elderly (aged 60 years and over)

28

from the Cohort of Elderly Health and Environment Controllable Factors

29

in West Anhui of China. Then, 45 representative antibiotics and 2

30

metabolites were monitored in urines by liquid chromatography

31

electrospray tandem mass spectrometry. The results revealed that 34

32

antibiotics were overall detected in 93.0% of all urine samples and the

33

detection frequencies of each antibiotic varied between 0.2% and 35.5%.

34

The overall detection frequencies of 7 human antibiotics (HAs), 10

35

veterinary antibiotics (VAs), 3 antibiotics preferred as HA (PHAs) and 14

36

preferred as VA (PVAs) in urines were 27.4%, 62.9%, 30.9% and 72.7%,

37

respectively. Notably, the samples with the concentrations of 6 PVAs

38

(sulfamethoxazole,

39

norfloxacin and lincomycin) above 5.0 × 103 ng/mL account for 1.7% of

40

total urine samples. Besides, in the remaining 62.7% of urine samples, the

41

total antibiotic concentration was in the range of the limits of detection

42

(LODs) to 20.0 ng/mL. Furthermore, the elderly with the sum of

43

estimated daily intake (EDI) of VAs and PVAs more than 1 µg/kg/day

44

accounted for 15.2% of all participants, and 6.7% of the elderly might

trimethoprim,

2

oxytetracycline,

danofloxacin,

45

under a health risk related to the gut microbiota changing under

46

antibiotics stimulation. Especially, ciprofloxacin was the foremost

47

contributor to the health risk and its hazard quotient value more than 1

48

was seen in 3.5% of all subjects. Taken together, the Chinese elderly were

49

extensively exposed to veterinary antibiotics and some elderly may under

50

a health risk linked to dysbiosis of the gut microbiota.

51

Capsule: 34 antibiotics were detected in 93% urines of 990 elderly and

52

health risk related to gut microbiota was revealed in 6.7% of the elderly.

53

Keywords: Antibiotics; Elderly; Urine; Health risk assessment.

54 55 56 57 58 59 60 61 62 63 64 65 66 3

67

1. Introduction

68

Antibiotics are not only used in the prevention and treatment of bacterial

69

infection occurred in humans and animals (Nathan, 2014) but also

70

extensively added to serve as growth factors in aquaculture and animal

71

husbandry (Van Boeckel et al., 2017). Owing to the abuse and improper

72

usage, these antibiotics were often detected in surface water, soil and food

73

(Guo et al., 2019; Sun et al., 2017; Yamaguchi et al., 2015). To date,

74

numerous publications have demonstrated that approximately 70-80

75

antibiotics and their metabolites were measured in animal-derived food

76

and drinking water worldwide (Chen et al., 2015; Wang et al., 2017a;

77

Wang et al., 2016b; Yamaguchi et al., 2015). Thus, the antibiotics

78

residues in food and the environment can be transferred to humans

79

through the food chain, which may cause bioaccumulation of antibiotics

80

in human body. Consequently, the ingestion of low-dose antibiotics for

81

extended periods of time could aggravate the growing battle with

82

emerging antibiotic-resistant pathogenic strains. What's the worse, the

83

exposure to antibiotics could increase the pesticide bioavailability via

84

disturbing gut microbiota and further may increase the pesticide exposure

85

risk (Zhan J, 2018). Additionally, increasing evidence has indicated that

86

antibiotics exposure can affect the composition and functionality of the

87

host microbiota (Becattini et al., 2016; Leclercq et al., 2017), and is one

88

of the potential risk factor for obesity (Bailey et al., 2014), diabetes 4

89

(Pearson JA, 2019), and even some nervous system diseases (Lurie et al.,

90

2015).

91

It is well-known that human biomonitoring is a powerful tool for

92

simultaneously analyzing the actual internal levels of bodily chemicals

93

from all potential routes of exposure, which may make contribution to

94

improve risk assessments. In recent years, several population-based

95

studies used urine as a sample to bio-monitor antibiotics (Li et al., 2017;

96

Wang et al., 2015; Wang et al., 2016a). For instances, more than 20

97

antibiotics were detected in Shanghai children’ urine samples and the

98

overall detected frequencies reached 79.6% (Wang et al., 2016a). Another

99

study has shown that 9 veterinary antibiotics were measured in 77.4% of

100

pre-school children urine samples in Hong Kong (Li et al., 2017). These

101

studies demonstrated that urine samples were suitable or convenient for

102

monitoring the amount of total antibiotic exposures in human body from

103

contaminated food and drinking water. Based on the studies conducted in

104

eastern China, the results showed that 4.3% of pregnant women (Wang et

105

al., 2017b), 6.0% of children (Wang et al., 2018a) and also 7.2% of

106

general adults (Wang et al., 2018b) had a health risk relevant to gut

107

microbiota.

108

Interestingly, a previous study conducted in Dalian of China has revealed

109

that in the general population (n=107), the serum concentrations for

110

sulfonamides, macrolides and chloramphenicols in elderly were higher 5

111

than those in young adults (Liu et al., 2017a). This finding implied that

112

the age may link to the antibiotic accumulation in human. As is well

113

known, ageing is accompanied by some physiologic alterations, including

114

reduced species diversity and declined metabolic activities of gut

115

microbiota, which may negatively influence the excretion process of

116

antibiotics (An R, 2018; Woodmansey et al., 2004). Moreover, the elderly

117

are vulnerable to bacterial infection disease because of their compromised

118

immune function (An R, 2018) which is the reason why antibiotics are

119

prescribed more frequently to elderly than that to younger. The

120

abovementioned results indicated that the elderly have a higher risk of

121

antibiotics bioaccumulation compared with younger. However, until now,

122

the information for antibiotic body burden and potential health risk in the

123

elderly population is seldom being investigated.

124

To our best knowledge, this is the first study focusing on antibiotics

125

exposure examination using bio-monitoring data based on an elderly

126

cohort. Here, we monitored 45 antibiotics and 2 metabolites in urine

127

samples from approximately 1000 elderly in Lu’an city of west Anhui

128

province in China and assessed health risks of antibiotics for the elderly

129

based on microbiological or toxicological effects. Our study may provide

130

new insights into the effect of antibiotics exposure on healthy ageing.

131

2. Materials and methods

132

2.1. Study population and sample collection 6

133

The data reported in this study came from the baseline survey of the

134

Elderly Health and Environment Risk Factor (EHERF) cohort, which was

135

conducted in Lu'an Municipality, West Anhui, China, since June to

136

September in 2016. Detailed procedures of elderly person recruitment and

137

of questionnaire survey were described in our previous article (Li et al.,

138

2019). Briefly, all participants aged more than 60 years and live in two

139

communities including rural community in Ji’an (JA) and an urban

140

community in Yu’an (YA). For physical examination, each participant

141

was asked to collect a morning urine sample (at least 30 mL) before they

142

came to the local community hospitals. The collected urine samples were

143

stored at −80 °C prior to the analyses of the target antibiotics. Of 1080

144

participants, 59 participants did not provide urine samples, 31 participants’

145

urine sample analysis lack urine creatinine information; therefore, we

146

eventually included 990 subjects in our analysis. No significant

147

differences were found in age (mean age, 71.8 and 73.2 years) and gender

148

ratio (54.4% and 53.3% female) between the included and the excluded

149

(P > 0.05). In fact, we measured 1021 urine samples in this study, the

150

detected frequencies and volume-based concentrations were shown in

151

Table S1. The whole participants have provided informed consent form.

152

This study was approved by the ethical committee of Anhui Medical

153

University.

154

2.2. Selection of Antibiotics 7

155

Because of the abuse and unreasonable application in aquaculture and

156

animal husbandry, antibiotics were frequently detected in aquatic

157

products and animal-derived food (Chen et al., 2015; Wang et al., 2017a),

158

therefore, exposure to antibiotics via dietary intake for the elderly should

159

not be omitted. In this study, apart from human antibiotics (HAs) and

160

antibiotics preferred as HA (PHAs), we also screened the veterinary

161

antibiotics (VAs) and antibiotics preferred as VA (PVAs). Ultimately,

162

according to the detected antibiotics in foods of animal origin (Du et al.,

163

2019; Wang et al., 2017a; Zhao et al., 2018; Zhou et al., 2013) and human

164

urines (Wang et al., 2015; Wang et al., 2017b; Wang et al., 2016a; Wang

165

et al., 2018b), we selected 45 antibiotics and 2 metabolites (Table S2)

166

including 9 sulfonamides (SAs), 10 fluoroquinolones (FQs), 7 macrolides

167

(MAs), 8 β-lactams (LAs), 4 tetracyclines (TCs), 3 phenicols (PCs), 2

168

quinoxalines (QUs), lincomycin (LIN), spectinomycin (SPC), florfenicol

169

amine, N4-acetyl -sulfamonomethoxine. All standards were purchased

170

from Sigma-Aldrich (St Louis, MO, USA), Dr Ehrenstorfer (Augsburg,

171

Germany) and TRC (North York, Canada).

172

2.3. Urine sample preparation

173

The sample preparation was referred to the previous methodology with

174

minor modification (He-Xing et al., 2014). Briefly, urine samples were

175

thawed and centrifuged for 5 min at 2000 rpm at 4 °C, 1.0-mL urine

176

supernatant was buffered with 200 µL of Na2EDTA-McIlvaine buffer (pH 8

177

4.0). Then the mixture was spiked with 15 µL β-glucuronidase aqueous

178

solution (

10000 units/mL) from Helix pomatia (type H-2,

179

Sigma-Aldrich) and 20 µL of mixed internal standards (2 µg/mL of

180

sulfamethoxazole-D4, trimethoprim-D3, ofloxacin-D3, azithromycin-D3,

181

ceftiofur-D3,

182

lincomycin-D3, 4 µg/mL of amoxicillin-D4), vortexed thoroughly and kept

183

at 37 °C overnight to hydrolyze the analyte conjugates. After hydrolysis,

184

the mixture was transferred onto a reversed phase Waters® Oasis

185

hydrophilic–lipophilic–balanced (HLB) cartridge (60 mg, 3 mL; 30 µm),

186

which was preconditioned with 1.2 mL of pure methanol and equilibrated

187

with 1.2 mL of ultrapure water. Subsequently, the cartridge was washed

188

with 1.2 mL of ultrapure water and 1.2 mL of 30 % methanol-water

189

solution to remove matrix interferences. The antibiotics kept in cartridges

190

were eluted by 2 mL of pure methanol and concentrated to near dryness at

191

45 °C under a gentle nitrogen stream, then re-dissolved in 200 µL of 5 %

192

acetonitrile-water solution. Finally, the solution was filtered by 0.22 µm

193

hydrophilic membrane and 15 µL of the extracts were injected for

194

HPLC-MS/MS analysis.

195

2.4. Instrument analysis

196

In the Anhui Provincial Key Laboratory of Population Health &

197

Aristogenics (Anhui Medical University, Hefei City, China), urinary

198

antibiotics

doxycycline-D3,

were

measured

florfenicol-D3,

by 9

a

penicillinV-D5

high-performance

and

liquid

199

chromatograph-tandem mass spectrometry (HPLC, Agilent 1200; MS,

200

Agilent 6410B). Based on the previous method with a few minor

201

modifications (Liu et al., 2017a), the analytes were separated on the

202

ZORBAX SB-C18 column (2.10 mm ×150 mm 3.50 µm Agilent,

203

USA), at a column temperature 35 °C and a flow rate of 0.4 mL/min. The

204

gradient elution program was different between positive ion and negative

205

ion modes and shown in Table S3 and Table S4. All LC-MS grade

206

solvents (water, formic acid and acetonitrile) were from Honeywell

207

International Inc (Morristown, NJ, USA). The fragment voltages,

208

collision energies and retention times of individual antibiotic are shown

209

in Table S2. Other MS conditions are as follows: drying gas temperature,

210

350 °C; drying gas flow, 10 L/min; capillary voltage, 4000 V; nebulizer

211

pressure, 40 Psi. The dynamic multiple reaction monitoring (dMRM)

212

mode was used for all data acquisition.

213

2.5. Quantification and quality control

214

Urinary antibiotics were quantified using an isotope dilution method. A

215

nine-point calibration curve from 0.5 to 200 ng/mL was prepared for all

216

analyzed antibiotics. The regression coefficients (R2) ranged from 0.990

217

to 0.999. The limits of detection (LODs) and limits of quantitation (LOQs)

218

were defined as a signal-to-noise ratio of 3 and 10, respectively. The

219

LODs of the screened antibiotics ranged from 0.03 to 2.15 ng/mL, while

220

the LOQs between 0.11 and 6.02 ng/mL. Two spiked urine samples at 20 10

221

ng/mL were used to monitor the precision and trueness of analytical

222

procedure. Procedural and instrumental blanks were also prepared for

223

each batch to avoid laboratory contamination and analytical interferences.

224

The recoveries of analyzed antibiotics ranged from 73.5% to 112.2% with

225

the relative standard deviations varying between 8.5% and 14.6%, and the

226

matrix effects between 57.5% and 123.7% with the relative standard

227

deviations varying between 11.4% and 19.7%.

228

2.6. Daily exposure dose estimation

229

We calculated the estimated daily intake (EDI) of antibiotics using the

230

following equation (Katrine et al., 2014; Wang et al., 2017b):

231

EDI (µg/kg/day)

Caj (µg/g)×CE(g/day)

(1)

bw(kg)×P

232

Caj was the creatinine-adjusted concentration of antibiotics, bw was the

233

body weight, P represented antibiotic excretion rate in urine as

234

unchanged and glucuronide-conjugated forms, which were derived from

235

human pharmacokinetic studies (Table S5). As for sulfachinoxalin,

236

sulfaclozine, sulfachloropyridazine, sarafloxacin and cyadox, the urinary

237

excretion rates from animals were used due to lack of data in human. CE

238

was the daily output of urinary creatinine, which calculated using

239

equation 2 and 3 (Mage et al., 2008) (Ht: height, cm).

240

CEmale (g/day)

×(bw1.5×Ht0.5)/106

241 242

0.926×1.93×(140–age)

CEfemale (g/day)

0.993×1.64×(140–age) 11

(2)

×(bw1.5×Ht0.5)/ 106

243

(3)

244 245

2.7. Health risk assessment

246

On the basis of EDI estimations, we further calculated HQs and HIs to

247

assess health risks from a single antibiotic exposure and combined

248

exposure, respectively. The formula was as follows (Gao et al., 2017;

249

Wang et al., 2017b): HQ

250

EDI(µg/kg bw/day) ADI(µg/kg bw/day)

;

HI=∑ HQ

251

Given that most of antibiotics belong to antibacterial agents, they mainly

252

pose impacts on gut microbiota (Becattini et al., 2016; Leclercq et al.,

253

2017). Thus, the microbiological effect-based acceptable daily intake

254

(ADI) of individual antibiotic was used to calculate HQ. The ADI used in

255

this study was derived from literature or established by authorities and

256

shown in Table S6. In the current study, HI was the sum of the HQ for

257

individual antibiotic, but except for HAs and PHAs. We assumed a

258

potential health risk would occur when the HI value for an elderly was >

259

1.

260

2.8. Statistical analysis

261

In the current study, based on the antibacterial mechanisms, we

262

categorized 34 antibiotics into eight categories (SAs, FQs, MAs, LAs,

263

TCs, PCs, QUs and LINs). Moreover, four new variables grouped by their

264

usages were HAs, VAs, PHAs and PVAs. Generally, in one urine sample, 12

265

a detection of one or more antibiotics in a category was regard as a

266

positive detection of the corresponding category. Creatinine corrected

267

concentrations of antibiotics were used to assess their exposure in urines.

268

Body mass index (BMI) was calculated as the ratio of body weight (kg)

269

to height squared (m2). All subjects were categorized into two groups of

270

normal weight (BMI < 24) and overweight (BMI

271

BMI-based cutoff values of Chinese adults proposed by the Working

272

Group on Obesity in China(Zhou, 2002). Pearson chi-square test or the

273

non-parameters test was used to examine the gender, age, regional and

274

BMI differences in the detection frequencies or concentrations of

275

individual antibiotics or categories. The binomial logistic regression

276

model was performed to estimate the relation and odds ratios for gender,

277

age, study site and BMI in association with antibiotic detection rates.

278

Values below the LODs were treated as zero for the calculation of total

279

concentrations, means, and medians. However, when performing

280

statistical analyses, those below the LODs were taken as 1/2 LODs.

281

Statistical analyses were performed using SPSS Version 23.0 software

282

(Chicago, IL, USA), statistical significance was set at P < 0.05 in the

283

current study.

284

3. Results

285

3.1. Detection concentrations and frequencies of antibiotics

286

In this study, Table 1 showed that 34 antibiotics were detected in 93.0% 13

24) according to the

287

of all urines samples, the detection frequencies of individual antibiotic

288

ranged from 0.2% to 35.5%. The predominantly categories in urines were

289

sulfonamides and fluoroquinolones, with the detection frequencies of

290

55.8% and 50.1%, respectively. In addition, two or more antibiotics were

291

simultaneously detected in above 70% samples. Moreover, 10 VAs or

292

PVAs, including sulfaclozine, ofloxacin, florfenicol, trimethoprim,

293

tetracycline, oxytetracycline, doxycycline, ciprofloxacin, norfloxacin and

294

enrofloxacin, were extensively detected in urines, which detection rates

295

were more than 10%. Sulfaclozine (35.5%) and ofloxacin (23.7%) were

296

the most frequently detected in VAs and PVAs, respectively. And the total

297

detection rates of both VAs and PVAs in our study were 62.9% and 72.7%

298

(Table S7).

299

Figure 1 showed that the majority of antibiotic concentration values in

300

the urine samples were in the range of the LODs to 20 ng/mL. However,

301

it is worth noting that 4.8% of urines were detected to contain antibiotics

302

more

303

sulfamethoxazole, trimethoprim, oxytetracycline, danofloxacin and

304

lincomycin) which content were even higher than 5000 ng/mL in urines

305

of very few elderly (Table 1). Perhaps, the extreme values of urinary

306

antibiotic concentrations were achieved by direct intakes of antibiotics,

307

such as clinical use, self-medication or an unknown cause. However, the

308

abovementioned antibiotics, biological half-lives were quite low usually

than

500

ng/mL,

especially

14

the

6

PVAs

(norfloxacin,

309

less than 20 hours (Liu et al., 2017a), could be quickly excreted from

310

human bodies. Therefore, we speculated that the higher concentrations

311

probably were obtained from a continuous intake of antibiotics seriously

312

contaminated foods or drinking water.

313

3.2. Relationship among detection frequencies with study site, age,

314

gender, and BMI

315

Table 2 presented the differences in detection frequencies of urinary

316

antibiotics among different study sites, age, gender and BMI. The

317

detection

318

sulfaclozine, oxytetracycline, ofloxacin and ciprofloxacin, were higher in

319

subjects from the rural area than those from the urban area (P < 0.05) and

320

a similar trend was observed for the category of VAs (P > 0.05). For

321

age-related

322

tetracycline and enrofloxacin) were more likely to be detected in older

323

subjects (aged > 70 years). The categories of SAs and PVAs were more

324

frequently found in men than women. Furthermore, BMI-related

325

differences were also observed in this study. The detection frequencies of

326

3 PVAs (chlortetracycline, norfloxacin and sulfachloropyridazine)

327

showed a significantly higher level in overweight group (BMI ≥ 24) than

328

normal weight group (BMI < 24), but sulfaclozine and ofloxacin were the

329

opposite (P < 0.05). Table S10 showed the adjusted associations between

330

study site, age, gender, and BMI and the detection frequencies of

frequencies

differences,

of

4

5

PVAs,

PVAs

15

including

sulfamethoxazole,

(sulfamethoxazole,

sulfadiazine,

331

antibiotics in urines, the above differences and trends remained the same

332

after adjustment for covariates. Table S11 presented the correlation

333

between study site, age, gender, and BMI and antibiotics concentration in

334

urines, the results revealed that the group with a higher detection

335

frequency often had a higher concentration of antibiotic in urine sample.

336

3.3. Estimated daily intake and health risk assessment

337

Figure 2 displayed the elderly with the total EDI greater than 1 µg/kg/day

338

accounted for 17.1% of all participants. Table 3 revealed that the extreme

339

values of 3 PVAs (sulfamethoxazole, norfloxacin and lincomycin) were

340

more than 500 µg/kg/day and the maximum value of 5450.45 µg/kg/day

341

was seen in a VA (danofloxacin). Moreover, as presented in Table S8, the

342

PVAs had the higher EDI than either HAs or PHAs. Table 4 showed that

343

12 antibiotics (2 VAs and 10 PVAs) were observed to pose a

344

microbiological effect-related health risk on 6.7% of the elderly in this

345

study. Specifically, ciprofloxacin (3.5%) was a most important

346

contributor to the potential health risk related to gut microbiota, followed

347

by

348

sulfamethoxazole were found to pose a toxicological effect-related health

349

risk in 0.3% of all subjects. Although the detection frequencies of

350

florfenicol and ofloxacin reached 23.0% and 23.7%, respectively, they

351

did not pose health risks on the elderly in this study. Even so, it did not

352

mean there were no negative effects on human health under a continuous

oxytetracycline

(1.1%)

and

16

lincomycin

(0.7%).

Besides,

353

exposure scenario.

354

4. Discussion

355

In the current study, 34 antibiotics were detected in the urine of the

356

elderly from West Anhui of China, with a total detection frequency

357

reaching 93%. The 10 veterinary antibiotics were found in 62.9% of urine

358

samples. Furthermore, the majority of the subjects had a total antibiotic

359

concentration ranging from the LODs to 20.0 ng/mL. And the HI value of

360

more than 1 was observed in 6.7% of the elderly. These results indicated

361

that the elderly were extensively exposed to antibiotics, especially VAs

362

and PVAs, and some elderly were under a health risk linked to dysbiosis

363

of the gut microbiota.

364

4.1. Exposure sources of antibiotics in the elderly

365

In general, antibiotics are the primary drugs for treat and prevent bacterial

366

infections in human and animal (Nathan, 2014). Also, antibiotics are

367

extensively added to serve as growth factors in aquaculture and animal

368

husbandry (Van Boeckel et al., 2017). Owing to the highest rates of

369

antibiotic use, first, clinical use is the main source for the elderly exposed

370

to HAs and PHAs in our study. Second, ingesting contaminated food

371

might be the most important source for the indirect exposure to

372

antibiotics (Wang et al., 2015; Wang et al., 2017b). For instance,

373

fluoroquinolones were the most frequently detected category in aquatic

374

products and had high residual levels (Liu et al., 2017b). In the current 17

375

study, 50.0% of the elderly were exposed to fluoroquinolones and the

376

detection frequencies of both ciprofloxacin and ofloxacin were more than

377

15.0%. Moreover, sulfonamides were detected in meat foods, the

378

maximum residue level in pork and chicken reached 3.6 × 103 µg/kg and

379

2.7 × 103 µg/kg (Yamaguchi et al., 2015), respectively. Also,

380

sulfonamides were frequently detected in the elderly of this study, with a

381

detection rate of 55.8%. A study conducted in Korea adults indicated that

382

after 5-day diet without animal-derived food, the urinary levels of 2 PVAs

383

(trimethoprim and ciprofloxacin) were significantly reduced (Ji et al.,

384

2010). Finally, drinking water was contaminated by some antibiotics with

385

lower concentrations, but played a limited role in antibiotic exposure of

386

elderly (Li et al., 2017; Wang et al., 2016b). Therefore, the VAs and PVAs

387

detected in urines of the elderly might primarily derive from long-term

388

ingesting contaminated food of animal origin, such as pork, fish and milk.

389

4.2. Differences of antibiotic across study sites, age, gender and BMI

390

In the current study, the detected frequencies and concentrations of some

391

antibiotics varied by age, gender, study site and BMI. For example,

392

sulfamethoxazole, tetracycline and enrofloxacin were more likely to be

393

found in the older age group which might be related to a declining

394

excretory capacity in the older. The detection frequency of PVAs was

395

higher in males than females, this could be partly explained as the sex

396

difference of dietary habits or lifestyles. Generally, the males or the 18

397

overweight adults may intake higher amount of animal food than females

398

or the normal weight ones (Fraser et al., 2000; Zou et al., 2017), which

399

may increase the risk of exposure to VAs or PVAs from food.

400

Consequently, both sulfachloropyridazine and chlortetracycline showed

401

significantly higher levels in overweight group than in the normal weight.

402

We also found some differences of urinary antibiotics across various

403

study sites. For example, the detected frequencies and concentrations of

404

VAs or PVAs, including lincomycin, ofloxacin and oxytetracycline, were

405

higher in subjects from rural area than those in urban area. In the majority

406

of rural areas of China, the treatment rate of sewage and livestock wastes

407

are quite low due to the limited infrastructure (Zhang et al., 2015). As a

408

result, antibiotics contained by animal wastes may be discharged directly

409

into the environment, which is the reason why the rural population has

410

higher opportunity to exposure the VAs and PVAs from environment.

411

Additionally, the elderly from urban area were more likely to

412

self-medication with antibiotics than those from rural area (Torres et al.,

413

2019), which is consistent with our study that the HAs (macrolides) have

414

a higher exposure level in subjects from the urban area.

415

4.3. Comparisons with other studies

416

Bio-monitoring data have indicated a widespread antibiotics exposure of

417

different populations, but most of subjects are children or younger adults

418

rather than the elderly (Wang et al., 2018a; Wang et al., 2015; Wang et al., 19

419

2017b; Wang et al., 2016a; Wang et al., 2018b). In our current study, the

420

overall detection frequency (93.0%) showed a higher level compared to

421

that school children in Shanghai (79.6%) (Wang et al., 2016a) or Hong

422

Kong (77.4%) (Li et al., 2017), pregnant women in Eastern China (41.6%)

423

(Wang et al., 2017b) and normal adults in Shanghai (45.9%) (Wang et al.,

424

2018b) or Dalian (41.1%) (Liu et al., 2017a). Probably, the elderly are

425

more susceptible to bacterial infection and some of them with chronic

426

disease (An R, 2018), which is the reason why antibiotics are prescribed

427

more frequently to elderly. If so, it is reasonable that the elderly have a

428

higher exposure level of antibiotics compared with adults in China. For

429

instance, azithromycin, the most commonly prescribed antibiotic in the

430

elderly (Kabbani et al., 2018), was detected in 18.2% of urine samples in

431

our study, much higher than 1.6% of adults (Wang et al., 2018b) and 1.3%

432

of pregnant women (Wang et al., 2017b). As for the VAs or PVAs, due to

433

they were mainly obtained from ingesting contaminated food of animal

434

origin, the exposure level of them in urines would influence by the

435

dietary habits. Compared with the youngers, the elderly ate red meats

436

more frequently (Fraser et al., 2000), such as pork and beef often

437

contaminated by tetracyclines, norofloxacin and florfenicol (Li et al.,

438

2017; Wang et al., 2017a). Consequently, as shown in Figure 3,

439

oxytetracycline (18.9%), chlorotetracycline (7.8%), tetracycline (19.5%),

440

doxycycline (18.4%), norofloxacin (11.8%) and florfenicol (23.0%) were 20

441

at a higher level in urines from the elderly than other populations (Wang

442

et al., 2018a; Wang et al., 2015; Wang et al., 2017b; Wang et al., 2016a;

443

Wang et al., 2018b).

444

Ciprofloxacin had a comparable detection frequency to the recent studies,

445

but its concentration in elderly of this study (99th percentile concentration:

446

33.6 ng/mL) was higher than other populations (99th percentile

447

concentration: 19.0 ng/mL in general adults (Wang et al., 2018b), 9.2

448

ng/mL in pregnant women (Wang et al., 2017b) and 5.5 ng/mL in children

449

(Wang et al., 2015)). Maybe, it is the reason that aging is accompanied by

450

the decline of nephron number and renal cortical volume, which induces a

451

decline in glomerular filtration rate and alterations in the endocrine

452

activity of the kidney (Rowland et al., 2018). As a result, there would be a

453

lower excretion rate of antibiotics in the elderly, which might explain the

454

higher concentrations in urines of the elderly in our study. Also, the 99th

455

percentile concentration (217 ng/mL) of norfloxacin in this study was far

456

higher than those in adults, pregnant women and children (Wang et al.,

457

2015; Wang et al., 2017b; Wang et al., 2018b). Taken together, there was

458

a heavy antibiotic body burden in the Chinese elderly and it is essential to

459

assess the potential health risks.

460

4.4. Health risk assessment

461

In the resent years, numerous studies confirmed that the composition and

462

function diversity of gut microbiota could be changed or even disrupted 21

463

in a low dose of antibiotic stimulation. For instance, oral vancomycin,

464

ciprofloxacin and metronidazole had a profound and long-lasting effect

465

on microbiota composition (Ferrer et al., 2017; Haak et al., 2018; Isaac et

466

al., 2017). This disruption of the gut microbiota is harmful to the human

467

host because the gut microbiota is important for human immune and

468

metabolic functions (Zmora et al., 2017). Growing evidence has

469

demonstrated that exposure to antibiotics may increase the risk of getting

470

obesity (Stark CM, 2019), inflammatory bowel diseases (Balram et al.,

471

2019) and colorectal adenoma (Cao et al., 2017). Most of the previous

472

studies mainly focused on the effects of clinical antibiotics, which were

473

commonly with a short-term and high-dose exposure mode, on human

474

health. Pitifully, there is still limited information regarding the effects on

475

human health of long-term exposure to low-dose antibiotics.

476

In the current study, we assessed the health risk of 20 VAs or PVAs were

477

assessed based on microbiological effect, that of three sulfonamides and

478

cyadox were based on toxicological effect. Of the detected antibiotics, the

479

ones including 3 tetracyclines, 6 fluoroquinolones, and 3 other antibiotics

480

(trimethoprim, thiamphenicol and lincomycin) were found to pose a

481

microbiological effect-related health risk in 6.7% of the elderly, which

482

was higher than that 4.3% of the pregnant women (Wang et al., 2017b)

483

and 6.0% of the children (Wang et al., 2018a), but lower than 7.2% of the

484

general adults (Wang et al., 2018b). Notably, ciprofloxacin was a most 22

485

important contributor to the potential health risk related to gut microbiota

486

in this study, consistent with the published articles (Wang et al., 2018a;

487

Wang et al., 2017b; Wang et al., 2018b). Therefore, the government

488

should formulate the usage guidelines of ciprofloxacin for human and

489

animals. Moreover, it is worthy of paying attention that 1.1% of the

490

elderly had HQ value of oxytetracycline more than 1 in our study. We

491

also found that sulfamethoxazole caused a toxicological effect-based

492

health risk in 0.3% of all subjects, which was not reported in previous

493

studies. These findings showed exposures of VAs or PVAs might pose a

494

higher health risk to the elderly, either related to microbiological or

495

toxicological effects. Further investigation should be required to elucidate

496

the underlying mechanisms by which low level antibiotic exposure

497

induces adverse health effects in elderly.

498

4.5. Strengths and limitations

499

To our best knowledge, this is the first study dedicated to investigate the

500

antibiotic body burden of the elderly in larger sample sizes using a

501

biomonitoring approach. We measured 45 common used antibiotics and 2

502

metabolites in urines of the elderly, which may better reflect the

503

cumulative antibiotic exposure from environment, food or drinking water.

504

Moreover, we also assessed the potential health risk relevant to the gut

505

microbiota for the elderly. This study may provide new insights into the

506

effect of antibiotics exposure on healthy ageing. 23

507

However, there are some uncertainties and limitations in this study. First,

508

antibiotics residues and utilization vary widely by geographical area

509

(Zhang et al., 2015), but the participants only come from the Lu’an city,

510

West Anhui. Therefore, the subjects might not entirely represent the

511

elderly population in China. Second, the two metabolites, N4-acetyl

512

-sulfamonomethoxine and florfenicol amine, were used to estimate the

513

total exposure of sulfamonomethoxine and florfenicol, but the other

514

antibiotics were only measured unchanged species, which might

515

underestimate true antibiotic exposure in human. In the future study, more

516

metabolites of targeted antibiotics should be bio-monitored in human

517

urines. Third, most detected antibiotics have a relatively low biological

518

half-live (< 20 h) (Liu et al., 2017a), thus, the first morning urine is

519

merely able to reflect the antibiotics exposure condition in a short period

520

of

521

sulfachloropyridazine, sarafloxacin and cyadox), due to lacking of human

522

pharmacokinetic data, the reference data of proportion of antibiotic

523

excretion in urine are consulted from animals’ experiments which might

524

have an impact on the EDI of antibiotics.

525

Declaration of conflicting interests

526

The authors declare no conflicts of interest.

527

Acknowledgements

528

This work was supported by the Key Projects of Natural Science

time.

Finally,

for

several

24

antibiotics

(sulfaclozine,

529

Research in Colleges and Universities of Anhui province (KJ2018A0164,

530

KJ2017A189) National Natural Science Foundation of China (81202209)

531

and the Key Projects introduced and funded by leading talent teams of

532

colleges and universities of Anhui province (0303011224). We are deeply

533

grateful for the help provided by all the members in the experimental

534

center platform for physical and chemical of Anhui Medical University.

535

Supporting information

536

Additional text, tables, and figures providing details of analytical method

537

of urinary antibiotics, detection frequencies, concentration distribution,

538

estimated daily intakes and health risk assessment of HAs, VAs, PHAs

539

and PVAs; differences of antibiotic concentrations and detection

540

frequencies by age, gender and study site.

541 542

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31

Captions Table 1 Detection frequencies and concentrations of antibiotic in urines of Chinese Elderly (n = 990) Table 2 Differences of urinary antibiotic detection frequencies among different study site, age, sex and BMI (n = 990) Table 3 Estimated daily intake dose (EDI) of 34 antibiotics (n = 990) Table 4 Hazard quotient (HQ) based on acceptable daily intakes (ADIs) (n = 990)

Table 1 Detection frequencies and concentrations of antibiotic in urines of Chinese Elderly (n = 990)

Antibiotic

LOD

Sulfonamidesa

N (%)

Unadjusted (Creatinine adjusted)e P50

552 (55.8) 0.40(0.36)

-

Maximum

P75

P90

P95

P99

6.12 (5.15)

16.3 (14.6)

31.5 (27.8)

108 (130)

5.29 × 104 (5.18 × 104)

-

-

-

5.37 (6.45)

2.25 × 104 (2.20 × 104)

Sulfamethoxazole

0-0.45

26 (2.6)

Sulfaclozine

0-0.17

351 (35.5) -

4.30 (4.00)

13.9 (11.8)

23.7 (22.0)

76.3 (54.3)

1.52 × 103 (681)

Trimethoprimc

0-0.05

201 (20.3) -

-

0.53 (0.44)

1.38 (1.64)

11.3 (13.1)

3.05 × 104 (2.98 × 104)

Sulfamethazine

0-0.07

6 (0.6)

-

-

-

-

-

4.32 (5.90)

Sulfadiazine

0-0.16

28 (2.8)

-

-

-

-

1.85 (1.68)

118 (120)

Sulfachloropyridazine

0-0.09

45 (4.5)

-

-

-

-

3.19 (2.02)

13.6 (28.7)

d

0-0.10

65 (6.6)

-

-

-

0.78 (0.71)

5.06 (4.67)

75.2 (68.6)

0.07 (0.05)

0.55 (0.58)

2.91 (2.72)

30.8 (25.8)

7.75 × 103 (4.97 × 103)

Sulfamonomethoxine Macrolidesa

282 (28.5)

Erythromycin

0-0.12

85 (8.6)

-

-

-

1.15 (1.40)

13.5 (16.1)

7.75 × 103 (4.97 × 103)

Clarithromycin

0-0.05

27 (2.7)

-

-

-

-

0.22 (0.24)

4.23 (4.26)

Azithromycin

0-0.04

180 (18.2) -

-

0.09 (0.09)

0.20 (0.25)

5.93 (7.02)

1.35 × 103 (981)

Roxithromycin

0-0.04

27 (2.7)

-

-

-

-

0.39 (0.29)

1.28 × 103 (1.66 × 103)

0.25 (0.19)

2.54 (2.27)

7.07 (5.70)

136 (216)

8.77 × 103 (1.35 × 104)

β-lactamsa

253 (25.6)

Cefaclor

0-0.22

3 (0.3)

-

-

-

-

-

3.71 (9.60)

Cefotaxime

0-0.51

8 (0.8)

-

-

-

-

-

46.2 (24.0)

Penicillin V

0-0.20

176 (17.8) -

-

1.18 (1.02)

2.82 (2.35)

13.4 (9.72)

97.0 (164)

Amoxicillin

0-0.10

77 (7.8)

-

-

-

0.98 (1.03)

135 (215)

8.77 × 103 (1.35 × 104)

440 (44.4)

1.21 (1.03)

3.54 (3.23)

6.85 (7.41)

568 (608)

4.33 × 104 (3.06 × 104)

Tetracyclinesa Oxytetracycline

0-0.15

187 (18.9) -

-

0.70 (0.64)

1.87 (1.79)

349 (569)

4.30 × 104 (3.02 × 104)

Chlorotetracycline

0-0.11

77 (7.8)

-

-

-

1.26 (0.95)

7.79 (8.84)

531 (906)

Tetracycline

0-0.20

193 (19.5) -

-

1.01 (0.88)

2.18 (2.01)

14.2 (17.1)

706 (1.04 × 103)

0-0.19

182 (18.4) -

-

0.85 (0.73)

1.85 (1.58)

11.6 (10.4)

Doxycycline Fluoroquinolones

a

495 (50.0) 0.03(0.02)

3

54.6 (80.3) 3

2.66 (3.02)

23.6 (20.7)

62.3 (65.2)

1.51 × 10 (1.06 × 10 )

3.03 × 105 (1.80 × 105)

Pefloxacin

0-0.05

40 (4.0)

-

-

-

-

7.89 (5.11)

264 (343)

Lomefloxacin

0-0.08

14 (1.4)

-

-

-

-

0.38 (0.54)

3.68 × 103 (3.66 × 103)

Danofloxacin

0-0.12

40(4.0)

-

-

-

-

24.0 (19.5)

3.03 × 105 (1.58 × 105)

Sarafloxacin

0-0.05

16 (1.6)

-

-

-

-

0.38 (0.29)

196 (215)

Ofloxacin

0-0.03

235 (23.7) -

-

0.94 (0.92)

3.74 (3.92)

38.5 (42.7)

99.6 (114)

Levofloxacin

0-0.04

33 (3.3)

-

-

-

-

141 (157)

2.16 × 105 (1.80 × 105)

Difloxacin

0-0.05

7 (0.7)

-

-

-

-

-

16.0 (13.0)

Enrofloxacin

0-0.04

103 (10.4) -

-

0.08 (0.07)

0.74 (0.66)

6.71 (7.47)

48.1 (22.4)

Ciprofloxacin

0-0.06

163 (16.5) -

-

1.67 (1.51)

5.06 (4.41)

33.6 (34.9)

101 (123)

Norfloxacin

0-0.04

117 (11.8) -

-

1.00 (0.68)

5.36 (4.50)

217 (252)

4.83 × 104 (6.27 × 104)

247 (24.9)

0.07 (0.08)

3.36 (3.35)

6.06 (6.83)

79.2 (90.0)

1.90 × 103 (1.81 × 103)

Phenicolsa Chloramphenicol

0-0.51

27 (2.7)

-

-

-

-

54.6 (78.8)

1.90 × 103 (1.81 × 103)

Thiamphenicol

0-2.15

2 (0.2)

-

-

-

-

-

179 (204)

Florfenicold

0-0.10

228 (23.0) -

-

2.74 (2.60)

4.36 (4.64)

12.6 (11.7)

79.1 (112)

165 (162)

2.44 × 105 (1.95 × 105)

165 (162)

2.44 × 105 (1.95 × 105)

15.6 (12.0)

113 (79.3)

Lincosamides

a

Lincomycin

36 (3.6) 0-0.05

Quinoxalinesa Cyadox All antibioticb

36 (3.6)

-

-

-

-

29 (2.9) 0-1.45

29 (2.9)

-

921 (93.0) 8.82(7.94)

-

-

-

15.6 (12.0)

113 (79.3)

26.5(23.9)

100 (91.0)

413(437)

1.83 × 104 (2.28 × 104)

3.03 × 105 (1.95 × 105)

Notes: a, sum of concentrations of antibiotics in corresponding category for individual; b, sum of concentrations of all antibiotics; c, due to the similar antibacterial mechanisms, trimethoprim was included in the sulfonamides; d, the urinary levels of sulfamonomethoxine and florfenicol were separately considered to be the sum of their prototypes and metabolites (sulfamonomethoxine-N4-acetyl and florfenicol amine); e, volume-based urinary antibiotic concentration, ng/mL (creatinine adjusted urinary antibiotics concentration, µg/g); LODs, limits of detection ng/mL; N (%), the number of positive detection (detection frequency, %); P, percentile; -, < limits of detection (LODs).

Roxithromycin

3.7

1.6

0.042

3.0

2.5

0.614

3.8

1.9

0.0

Cefaclor

0.4

0.2

0.680

0.0

0.6

0.102

0.2

0.4

0.6

Cefotaxime

0.6

1.1

0.322

0.4

1.1

0.209

0.2

1.3

0.0

Penicillin V

16.6

19.2

0.275

17.0

18.5

0.522

16.6

18.7

0.3

Amoxicillin

10.5

4.5

<0.001

8.2

7.4

0.676

7.1

8.3

0.4

Oxytetracycline

23.6

13.2

<0.001

18.5

19.3

0.742

19.7

18.2

0.5

Chlorotetracycline

5.3

10.7

0.002

9.7

6.1

0.037

7.8

7.8

0.9

Tetracycline

21.0

17.7

0.189

14.8

23.7

<0.001

22.8

16.7

0.0

Doxycycline

14.0

23.7

<0.001

17.4

19.3

0.443

18.2

18.6

0.8

Pefloxacin

3.9

4.3

0.761

4.1

4.0

0.956

5.1

3.2

0.1

Lomefloxacin

1.8

0.9

0.209

1.5

1.3

0.825

1.1

1.7

0.4

Danofloxacin

5.0

2.9

0.101

3.2

4.8

0.216

3.5

4.5

0.4

Sarafloxacin

1.3

2.0

0.368

1.5

1.7

0.780

2.2

1.1

0.1

Ofloxacin

28.5

17.9

<0.001

23.4

24.0

0.809

22.8

24.5

0.5

Levofloxacin

3.7

2.9

0.499

2.6

4.0

0.210

2.4

4.1

0.1

Difloxacin

0.2

1.3

0.030

0.4

1.0

0.325

0.4

0.9

0.3

Enrofloxacin

10.5

10.3

0.916

8.2

12.4

0.029

11.1

9.8

0.5

Ciprofloxacin

18.8

13.6

0.030

17.0

16.0

0.696

17.1

16.0

0.6

Norfloxacin

12.9

10.7

0.298

9.9

13.7

0.061

13.3

10.8

0.2

Chloramphenicol

2.8

2.7

0.940

2.6

2.9

0.782

2.7

2.8

0.9

Thiamphenicol

0.4

0.0

0.199

0.0

0.4

0.182

0.0

0.4

0.1

Florfenicol

23.9

21.3

0.548

21.0

24.2

0.394

22.2

23.2

0.8

Lincomycin

5.3

1.6

0.002

2.8

4.4

0.180

4.4

3.0

0.2

Cyadox

4.4

1.3

0.005

2.6

3.4

0.431

3.3

2.8

0.6

Sulfonamides

56.7

54.6

0.501

56.4

55.2

0.684

60.8

51.6

0.0

Macrolides

19.7

39.1

<0.001

27.3

29.6

0.418

26.8

29.9

0.2

β-lactams

26.7

24.2

0.361

24.9

26.1

0.652

23.5

27.3

0.1

Tetracyclines

44.9

43.8

0.732

42.9

45.8

0.362

45.5

43.6

0.5

Fluoroquinolones

54.9

44.3

<0.001

47.6

52.3

0.144

49.7

50.5

0.8

Chloramphenicols

26.7

22.8

0.160

23.4

26.3

0.285

23.9

25.8

0.5

Veterinary antibiotic

65.4

60.0

0.079

63.1

62.8

0.921

64.5

61.6

0.3

Human antibiotic

19.3

37.1

<0.001

25.3

29.2

0.172

26.2

28.4

0.4

Preferred as HA

31.3

30.4

0.765

31.1

30.7

0.894

28.4

33.0

0.1

Preferred as VA

74.0

71.1

0.309

73.4

72.1

0.659

75.8

70.1

0.0

All antibiotic

93.7

92.2

0.335

93.1

92.9

0.905

94.7

91.7

0.0

Categories

a

b

Notes: , detection rate corresponding to specific characteristics, %; , p-values were calculated by Chi-squ VA, antibiotic; BMI, body mass index; two study sites: the rural area (n = 543) and the urban area (n = 44 (n = 466) and > 70 years (n = 524); two sex categorizes: males (n = 451) and females (n = 539); two BMI 24, n = 488) and overweight (BMI ≥ 24, n = 502).

Azithromycin

-

-

-

0.02

0.05

1.30

255

Roxithromycin

-

-

-

-

-

0.01

30.9

0.05

0.12

2.81

234

β-lactamsa Cefaclor

-

-

-

-

-

-

0.13

Cefotaxime

-

-

-

-

-

-

0.50

Penicillin V

-

-

-

0.02

0.05

0.18

2.74

Amoxicillin

-

-

-

-

0.01

2.34

234

0.01

0.02

0.06

0.14

10.9

430

Tetracyclinesa Oxytetracycline

-

-

-

0.01

0.03

9.30

424

Chlorotetracycline

-

-

-

-

0.02

0.21

19.0

Tetracycline

-

-

-

0.02

0.04

0.29

18.6

Doxycycline

-

-

-

0.01

0.03

0.18

1.27

0.02

0.06

0.52

1.30

20.4

5.45

Fluoroquinolonesa Pefloxacin

-

-

-

-

-

0.63

36.1

Lomefloxacin

-

-

-

-

-

0.01

53.9

Danofloxacin

-

-

-

-

-

0.89

5.45

Sarafloxacin

-

-

-

-

-

0.01

5.30

Ofloxacin

-

-

-

0.01

0.05

0.45

1.69

Levofloxacin

-

-

-

-

-

1.73

1.82

Difloxacin

-

-

-

-

-

-

0.20

Enrofloxacin

-

-

-

-

0.04

0.34

1.19

Ciprofloxacin

-

-

-

0.03

0.10

0.74

2.32

Norfloxacin

-

-

-

0.01

0.09

3.83

1.14

0.08

0.14

1.12

22.9

Phenicolsa Chloramphenicol

-

-

-

-

-

0.78

22.9

Thiamphenicol

-

-

-

-

-

-

3.24

Florfenicol

-

-

-

0.06

0.11

0.26

2.10

3.33

3.38

3.33

3.38

0.89

4.91

Lincosamides

a

Lincomycin Quinoxalines

-

Cyadox

-

All antibioticb a

-

-

-

-

a

0.18

0.36

0.60

2.09

9.04

0.89

4.91 3

3.78 × 10

5.45

Notes: , sum of estimated daily intakes of antibiotics in corresponding catego individual; b, sum of estimated daily intakes of all antibiotics; c, due to the si antibacterial mechanisms, trimethoprim was included in the sulfonamide percentile; -, < limits of detection (LODs).

Azithromycin

HA

-

-

-

0.01

0.03

0.77

150

Roxithromycin

HA

-

-

-

-

-

0.01

77.3

0.01

0.04

3.34

334

β-lactamsa Cefaclor

HA

-

-

-

-

-

-

-

Cefotaxime

HA

-

-

-

-

-

-

0.01

Penicillin V

PHA

-

-

-

-

0.01

0.03

0.46

Amoxicillin

PHA

-

-

-

-

0.02

3.34

334

0.01

0.02

0.05

3.62

143

Tetracyclinesa Oxytetracycline

PVA

-

-

-

-

0.01

3.10

141

Chlorotetracycline

PVA

-

-

-

-

0.01

0.07

6.34

Tetracycline

PVA

-

-

-

0.01

0.01

0.10

6.20

PVA

-

-

-

-

0.01

0.06

0.42

0.02

0.46

1.10

9.66

910

Doxycycline Fluoroquinolones

a

Pefloxacin

PVA

-

-

-

-

-

0.05

2.58

Lomefloxacin

PVA

-

-

-

-

-

-

26.9

Danofloxacin

VA

-

-

-

-

-

-

9.08

Sarafloxacin

VA

-

-

-

-

-

0.02

13.3

Ofloxacin

PVA

-

-

-

-

0.02

0.14

0.53

Levofloxacin

HA

-

-

-

-

-

0.87

910

Difloxacin

VA

-

-

-

-

-

-

0.11

Enrofloxacin

VA

-

-

-

-

0.01

0.06

0.19

Ciprofloxacin

PVA

-

-

-

0.21

0.65

4.96

15.5

Norfloxacin

PVA

-

-

-

-

0.01

0.27

81.3

0.03

0.05

0.45

9.16

Phenicolsa Chloramphenicol

HA

-

-

-

-

-

0.31

9.16

Thiamphenicol

PVA

-

-

-

-

-

-

1.30

Florfenicol

VA

-

-

-

0.02

0.04

0.09

0.70

0.33

338

0.33

338

0.01

0.03

Lincosamides

a

PVA

Lincomycin Quinoxalines Cyadox All antibioticb a

-

-

-

-

-

a

VA

-

-

0.02 0.04

-

-

-

0.01

0.03

0.08

0.58

2.76

73.5

2.92 × 10

Notes: , sum of hazard quotient of antibiotics in corresponding category for individu the sum of the HQ for individual antibiotic based on microbiological effects, but exce HAs and PHAs; c, due to the similar antibacterial mechanisms, trimethoprim was inc in the sulfonamides; HAs, human antibiotics; VAs, veterinary antibiotics; PVAs, antib preferred as VA; PHAs, antibiotics preferred as HA; P, percentile; N (%), number o or HI > 1 (percent in all, %); -, < limits of detection (LODs).

Figure captions: Figure 1 Frequency distribution of sum of concentrations of 34 antibiotics (n = 990) Figure 2 Frequency distribution of sum of estimated daily intake of 34 antibiotics (n = 990) Figure 3 Comparison of detection frequencies of 14 veterinary antibiotics or preferred as VA in urines between our study and four previous studies (SMX: Sulfamethoxazole; SMZ: Sulfamethazine; SDZ: Sulfadiazine; TMP: Trimethoprim; OTC: Oxytetracycline; CTC: Chlortetracycline; TC: Tetracycline; DC: Doxycycline; OFX: Ofloxacin; EFX: Enrofloxacin; CFX: Ciprofloxacin; NFX: Norfloxacin; TAP: Thiamphenicol; FF: Florfenico; #, corresponding antibiotic is not measured in urines)

22 20 17.0

Population proportion (%)

18 15.3

16

14.8

14.7

14 12

10.8

10.7

10 8

7.0

6

4.9

4.8

4 2 0
LOD-0.5

0.5-2.0

2.0-5.0

5.0-10.0 10.0-20.0 20.0-50.0 50.0-500.0500.0-Max

Antibiotics concentration (ng/mL)

Figure 1 Frequency distribution of sum of concentrations of 34 antibiotics (n = 990)

22 19.0

20

Population proportion (%)

18

16.5

16 14

12.5 11.5

12 9.6

10 8

11.2

7.0

6.8

5.9

6 4 2 0
LOD-0.02 0.02-0.05 0.05-0.10 0.10-0.20 0.20-0.50 0.50-1.00 1.00-5.00 5.00-Max

Estimated daily intake (µg/kg/day)

Figure 2 Frequency distribution of sum of estimated daily intake of 34 antibiotics (n = 990)

70

Wang et al., 2016 (586 school children in Shanghai) Ji et al., 2010 (541 general adults in Korea)

60

Wang et al., 2017 (536 pregnant women in East China)

Detection frequency (%)

Wang et al., 2018 (822 general adults in Shanghai) 50

Our research, 2019 (990 elderly in West Anhui)

40

30

20

10 #

0 TMP SMX SMZ

SDZ

#

OTC

# #

CTC

#

TC

##

DC

#

NFX

EFX

CFX

OFX

#

#

FF

TAP

Figure 3 Comparison of detection frequencies of 14 veterinary antibiotics or preferred as VA in urines between this study and four previous studies (SMX: Sulfamethoxazole; SMZ: Sulfamethazine; SDZ: Sulfadiazine; TMP: Trimethoprim; OTC: Oxytetracycline; CTC: Chlortetracycline; TC: Tetracycline; DC: Doxycycline; OFX: Ofloxacin; EFX: Enrofloxacin; CFX: Ciprofloxacin; NFX: Norfloxacin; TAP: Thiamphenicol; FF: Florfenico; #, corresponding antibiotic is not measured in urines)

Highlights 1. Thirty-four antibiotics were detected in urines of 990 elderly from the Elderly Health and Environment Risk Factor cohort. 2. Fourteen antibiotics preferred for veterinary use were found in 72.7% of the elderly urines. 3. A higher detection frequency of the antibiotics preferred for veterinary use in males than in females. 4. Ciprofloxacin was the foremost contributor to the health risk in 3.5% of all subjects. 5. A health risk related to gut microbiota was revealed in 6.7% of the elderly.

Conflict of Interest There is no conflict of interest.