Introduction

H. pylori is one of the most widespread and common bacterial infections associated with an increased risk of multiple diseases. In a recent multicenter cross-sectional study on H. pylori in urban China, its prevalence was found to be 27.08% in urban Chinese people and 40.66% in mainland China; however, prevalence and resistance rates showed considerable regional variations1,2. Furthermore, numerous previous studies demonstrated that H. pylori infection rates correlate with patients’ social economic status, living conditions, lifestyle habits, and other factors3,4. More specifically, some of the commonly identified risk factors included lower education level, lower socioeconomic status, poor hygiene, and history of smoking. While H. pylori is commonly treated with antibiotic, there is evidence to suggest that some factors might lead to treatment failure, including H. pylori-related factors, host factors, environmental factors, particularly in the presence of antibiotic resistance5. Previous studies reported H. pylori resistance rates as high in developing countries, with the clarithromycin and levofloxacin resistance rates amounting to 37% and 33% in China, respectively6. In China, many cities pay attention to H. pylori infection and its resistance, and numerous epidemiological surveys were conducted7,8,9. Previous studies have shown that the positivity rate of H. pylori antibodies was 51.8% in southern Fujian10. In the analysis of causes of death among residents in Quanzhou, malignant tumors rank first (31.59%)11, with the top four being lung cancer (27.52%), esophageal cancer (16.79%), liver cancer (12.24%), and gastric cancer (10.15%)12. Considering that the language and living habits in the Quanzhou area considerably differ from those in other provinces and cities in China, and it’s a high-risk area for digestive system diseases. In the present study, we focus on the Quanzhou area to investigate the H. pylori infection, evaluate antibiotic resistance, and identify risk factors specific to the region. The results of the present study are expected to contribute to effective prevention, control, and treatment for other high-risk areas of H. pylori infection, and comprehensively understand the public health situation, effectively manage disease risks, and optimize resource allocation.

Materials and methods

Participants

We conducted a cross-sectional study based on the data from the 910th Hospital of the Chinese People’s Liberation Army Joint Logistics Support Force and Anxi County Hospital, Quanzhou, Fujian. The participants were aged between 18 and 60 years old. The exclusion criteria were as follows: (1) history of an antibiotics therapy within the past month and proton pump inhibitors within the last 2 weeks; (2) treatment of H. pylori infection within the last 3 months; (3) cases complicated with serious diseases; (4) pregnancy and lactation. The participants were randomly and voluntarily enrolled with no specific incentive applied. The participants were guided and helped throughout the enrollment process to fill out survey questionnaires by trained physicians on site. Each participant was required to sign an informed consent, and all the data were used for the analysis only. Ethical clearance was obtained from the 910th Hospital of the Chinese People’s Liberation Army Joint Logistics Support Force Ethical Committee (Date2024-09–26/No125). All the experiments were performed in accordance with relevant guidelines and regulations.

Status of H. pylori infection

For gastric fluid collection, a minimally invasive string test using a commercial string test kit (Shenzhen Hongmed-Infagen Co. Ltd., China) was performed2. The participants were instructed to swallow a weighted capsule containing a coiled absorbent nylon thread with one end of the string attached to their cheeks. After 60 min, the capsule was dissolved and gastric fluid was absorbed by the nylon thread, after which the string was retrieved from the stomach. The string was then cut with sterile scissors at the indicated position to transfer the saline into the preservative solution (Tris/Saline/EDTA). All saline samples were then delivered to the Guangdong Center for Quality Control of Clinical Gene Testing in Guangdong Provincial People’s Hospital for the subsequent genetic analysis using the qPCR method.

The Stream SP96 Automated Nucleic Acid Extractor (Daan Gene Co. Ltd., China) with commercial genomic DNA extraction kit (Daan Gene Co. Ltd., China) was used for nucleic acid extraction. The Real-time PCR System Gentier 96R (Tianlong Technology Co. Ltd, China) was employed for real-time fluorescence quantitative PCR amplification. The detection targeted the H. pylori-specific ureA gene (Helicobacter pylori nucleic acid testing kit, Shenzhen Hongmed-Infagen Co. Ltd., China). The procedure of amplification that we applied was as follows: 2 min at 42 ℃, 2 min at 95 ℃, and then 40 cycles of 10 s at 95 ℃ and 45 s at 58 ℃. Any sample was considered to be H. pylori infection positive if the cycle threshold (Ct) value was below 35 with a typical S-shaped curve. The H. pylori 23 S rRNA and gyrA mutation detection kits (Shenzhen Hongmed-Infagen Co. Ltd., China) were used for antibiotic resistance detection against clarithromycin (A2142G, A2143G, and A2142C in 23 S rRNA gene) and levofloxacin (A260T, C261A, T261G, G271A, G271T, and A272G in gyrA gene) of H. pylori-positive samples. The cycle threshold (Ct) value below 30 with a typical S-shaped curve was regarded to indicate antibiotic resistance.

The questionnaire survey

The questionnaire survey was provided by Professor Gu Bing team2 of the Guangdong Provincial People’s Hospital. More specifically, we collected information about the participants’ demographic characteristics including age, sex, height, weight, body mass index (BMI), educational level, as well as their employment status, income, marital status, and number of members in the household. Furthermore, lifestyle included aspects such as sleep status, smoking behavior, stress feeling, severing of individual dishes, severing chopsticks and spoons, having dedicated tableware, sharing water glasses, fruits cleaning or peeling before eating, tooth brushing, halitosis, pet ownership, type of toilet in the household (seated toilet or squat toilet), toilet flushing with the toilet lid off, takeaway foods, restaurant meals, and having three regular meals. Dietary habits and food and beverage consumption were categorized as occasional (1–2 times/month or less), intermediate (1–2 times/week), and frequent (more than 3times/week). We also used the participants’ self-reported medical records to collect information about gastroscopy test, gastric symptoms (abdominal pain, belching, acid reflux, and bloating), diabetes, hypertension, hyperlipidemia, digestive diseases (chronic gastritis, gastric ulcer, gastrointestinal polyps, and acute gastritis), and relatives infected with H. pylori.

Statistical analyses

Statistical analyses were run using the SPSS statistical software package version 26.0 (SPSS Inc, Chicago, IL, USA) and R 4.0.4. Chi-square and binary logistic analysis were performed with H. pylori results as the outcome variable in H. pylori risk factor analysis. Associations between categorical variables were tested using Chi-square test and reported as numbers and percentages. Continuous variables (age, height, and weight) were presented as mean ± SD and analyzed using analysis of variance (ANOVA). When analyzing factors related to antibiotic resistance, univariate and multivariate regression analyses were conducted with antibiotic resistance results as the outcome variable. The odds ratios were calculated using logistic regression analysis; variables with p-value < 0.20 in the univariate analysis were included in the model and multivariate logistic analysis. Differences were considered to be significant at p < 0.05.

Results

Demographic characteristics of the study participants

Table 1 summarizes the characteristics of our study participants and the association between the demographic characteristics and H. pylori infection. A total of 293 participants (52.60%, 293/557) had a current or past history of H. pylori infection. The participants with high school or lower educational level tended to more frequently have H. pylori infection (56.27% vs. 49.32%). Most than half of the study participants with H. pylori infection were married (54.78%). Yet, the aforementioned trends did not reach statistical significance (Table 1). Specifically, the results of logistic regression analysis showed no statistically significant association between H. pylori infection and educational level (OR: 1.204, 95% CI: 0.841–1.724; p = 0.31) or marital status (OR: 0.723, 95% CI: 0.467–1.119; p = 0.145) (supplementary Table S1).

Table 1 Demographic characteristics and incidence of H. Pylori infection in the sample (univariate analysis).
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Lifestyle factors with incidence of H. pylori infection

H. pylori infection was found to be more prevalent among participants who reported eating fruits without prior leaning or peeling (64.10%) as compared to those cleaned or peeled fruits (51.74%); however, this difference did not reach statistical significance(supplementary Table S2). Furthermore, H. pylori infection had a negative relationship with takeaway foods (p = 0. 029). Table 2 shows the results of the logistic regression analysis. The participants who did not clean or peel fruits were more likely to develop H. pylori infection as compared to those with cleaned or peeled (OR: 0.470, 95% CI: 0.227–0.970; p = 0.041). In addition, H. pylori infection was significantly less likely to occur on the study participants who ate takeaway foods (OR: 0.650, 95% CI: 0.444–0.951; p = 0.027).

Table 2 Impact of hand washing before meals, hand washing after toilet use, fruits cleaning or peeling before eating, and having takeaway foods on incidence of H. Pylori infection (binary logistic regression).
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Dietary habits with H. pylori infection

Supplementary Table S3 shows the associations between dietary habits and food and beverages consumption in participants with and without H. pylori infection. The results revealed a significant negative relationship between the frequency of high-sugar foods (p = 0.050) and spicy foods (p = 0.046) and incidence of H. pylori infection. The tea intake ≥ 1 time/day was significantly higher among the H. pylori infected participants as compared to their non-infected counterparts. Furthermore, the H. pylori positive rate was higher (60.56%) in the respondents who reported drinking carbonated drinks as compared to those who did not (51.44%). Overall, there was no significant association between frequency of food or beverage consumption and H. pylori infection. While the results of logistic regression analysis showed an increased risk of H. pylori infection in participants who consumed tea ≥ 1 time per day (OR 1.576; 95% CI 1.108–2.241) and carbonated drinks ≥ 1 time per day (OR 1.890; 95% CI 1.106–3.231), the corresponding differences in the frequency of high-sugar food and spicy food consumption did not reach statistical significance (Table 3).

Table 3 Impact of the frequency of tea, carbonated drinks, high-sugar foods, and spicy foods consumption on incidence of H. Pylori infection (binary logistic regression).
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Association of medical conditions with H. pylori infection

H. pylori incidence rate was higher among participants with diabetes (66.67%) was than among those without diabetes (52.29%); however, this difference was not statistically significant. Furthermore, H. pylori infection was significantly more frequent among participants with hyperlipidemia (83.33%) as compared to their counterparts without this condition (p = 0.031). Finally, incidence of H. pylori was higher among the study participants without gastric symptoms (56.62%), gastroscopy test (57.71%), and digestive diseases (57.14%) (supplementary Table S4). Table 4 shows the results of the bivariate logistic regression analysis. The only medical condition that was significantly strongly associated with H. pylori infection was hyperlipidemia, with the study participants with hyperlipidemia being 5.235 times more likely to develop H. pylori infection as compared to those without (OR: 5.235, 95% CI:1.121–24.446; p = 0.035).

Table 4 Impact of gastroscopy, gastric symptoms, hyperlipidemia, and digestive diseases on incidence of H. Pylori infection (binary logistic regression analysis).
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Association between hyperlipidemia, tea, and carbonated drinks with incidence of H. pylori infection

We chose 231 H. pylori-positive participants those both tested for two antibiotics to perform resistance analysis. To evaluate the connection between hyperlipidemia, tea, and carbonated drinks with H. pylori infection, multivariable logistic models were constructed (Table 5). Hyperlipidemia (OR: 4.629, 95% CI: 1.005 ~ 21.323; p = 0.049) and tea intake ≥ 1 time per day (OR: 1.484, 95% CI: 1.058 ~ 2.082; p = 0.022) were found to be significantly associated H. pylori infection in Model 1. After adjustment for the potential confounding factors, H. pylori infection was found to be associated with an increased risk of hyperlipidemia; yet, the association did not reach statistical significance. Model 4 indicated that the incidence of H. pylori infection was higher among the study participants who consumed carbonated drinks, with an OR of 1.946 (95% CI: 1.112 ~ 3.404; p = 0.02), adjusted for educational level, marital status, hand washing before meals, hand washing after toilet use, fruits cleaning or peeling before eat, takeaway foods, high-sugar foods and spicy foods. In the fully adjusted analysis, the OR were 1.512 (95% CI: 1.030 ~ 2.221; p = 0.035) revealed a significant positive correlation between H. pylori infection and tea drinking (≥ 1 time per day).

Table 5 Association between hyperlipidemia, tea, and carbonated drinks with incidence of H. Pylori infection.
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Risk factors associated with antibiotic resistance of H. pylori

Antibiotic resistance rate of H. pylori to clarithromycin amounted to 48.92% (113/231), while that to levofloxacin was 44.59% (103/231). Risk factors associated with antibiotic resistance of H. pylori are summarized in Fig. 1 and Figure S1. Regarding antibiotic resistance rate of H. pylori to clarithromycin, such factors included high school or below educational level, shared tableware and gastroscopy test. Furthermore, the participants with bedtime after 24:00 (OR: 0.268, 95% CI: 0.083 ~ 0.869; p = 0.028), unsure halitosis (OR: 0.501, 95% CI: 0.253 ~ 0.993; p = 0.048) and frequently soybean and soy product consumption (OR: 0.420, 95% CI: 0.205 ~ 0.861; p = 0.018) had lower clarithromycin resistance rates. Further analysis of H. pylori positive population characteristics revealed that young (33.306 ± 8.465), highly educated (37/113, 59.68%), and married people were more likely to go to bed late and sleep less than 8 h/night (supplementary Table S5). The results of multivariate logistic analysis showed that people who shared glasses, frequently ate high sugar foods and barbecue (≥ 1–2 times/week) were more likely to develop clarithromycin resistance (p < 0.05); of note, however, former alcohol drinkers were less likely to develop resistance (OR: 0.137, 95% CI: 0.020 ~ 0.935; p = 0.042) (supplementary Table S6). With regard to levofloxacin, the results of univariate and multivariate logistic analysis showed that the study participants who brushed their teeth more than 2 times/day had a higher likelihood of developing levofloxacin resistance (p = 0.034 and p = 0.002, respectively). Other factors were not found to be associated with levofloxacin resistance (supplementary Table S7).

Fig. 1
figure 1

Demographic characteristics and lifestyle factors associated with antibiotic resistance of H. pylori.

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Risk factors associated with clarithromycin and levofloxacin resistance of H. pylori infection. OR1(95% CI): Odds Ratio and Confidence Interval of clarithromycin; OR2(95% CI): Odds Ratio and Confidence Interval of levofloxacin; P1: P value of clarithromycin; P2: P value of levofloxacin.

Discussion

The prevalence of H. pylorus, one of the most widespread and common bacterial infections, depends on multiple factors13. H. pylori infection is a risk factor associated with a variety of gastrointestinal diseases and malignancy. In this present cross-sectional study, we used a minimally invasive string test combined with qPCR to investigate the prevalence and association between several factors associated to H. pylori infection, as well as the resistance of H. pylori to antibiotics and risk factors in Quanzhou, Fujian. The overall H. pylori prevalence in the studied population amounted to 52.60%, which was higher than the corresponding prevalence rate observed among urban Chinese people (27.08%) and Fujian (42.58%) in a recent multicenter, cross-sectional study1.

Our results concerning the impact of demographic characteristics on the incidence of H. pylori infection are largely consistent with previous research (e.g4.). For instance, in line with several previous studies showing that people with low education level have a higher H. pylori infection rate3,14; we also found such a trend, albeit non-significant. Furthermore, concerning our finding that H. pylori infection was significantly less frequent among participants who would eat takeaway food could be due to the popularity and rapid development of takeaway eating that has dramatically changed the lifestyle associated with communal meals. The Chinese’ habit of having communal meals is related to their tradition of valuing family. However, it is difficult to fully implement serving of individual dishes or serving chopsticks in daily life. Takeaway foods turn communal meals into individual/independent meals, making it difficult for H. pylori infection to spread among people who eat together. In agreement with this line of thought, the results of our multivariate analysis showed that peeling or washing fruit before eating can reduce the risk of H. pylori infection. It is generally believed that the H. pylori infection is transmitted through the fecal-oral route, as well as through contaminated water and food. A higher level of hygiene awareness associated with peeling or washing fruit before eating can remove soil, dirt, and some pathogens from its surface, thereby reducing the risk of H. pylori infection.

Previous studies revealed that H. pylori infection varies in different groups due to environmental and social factors, dietary habits in different backgrounds. Prevalence differences were also found to be affected by research protocols, participant characteristics, detection methods and other factors. In the present study, we found that participants who only occasionally eat high-sugar, spicy foods are more likely to be infected with H. pylori infection as compared to those who frequently eat such foods. This finding can be attributed to the fact that the increased intake of capsaicin and high-sugar helps to inhibit the growth of H. pylori and thus becomes a protective factor15. Yet, according to our results, frequent tea and carbonated beverage consumption were risk factors for H. pylori infection. Overall, Quanzhou has a long history of tea related drinking, tea culture, and tea production. To date, available evidence on the connection between tea drinking and H. pylori infection is inconclusive. While previous studies indicated that tea drinking can reduce the risk of H. pylori infection16, others found that strong tea can increase the risk of H. pylori infection17. The reason underlying the observed divergence in the results may be related to the amounts of tea consumed, as well as to its concentration and frequency. Carbonated drinks can increase gastric reflux18, which may increase the risk of H. pylori infection; however, several studies showed it was not associated with H. pylori infection3,4.

In the results of our univariate analysis, H. pylori was associated with several medical conditions (none of gastric symptoms, gastroscopy test and digestive diseases); yet, this pattern was not replicated in multivariate analysis. Most H. pylori cases have no obvious clinical symptoms. It is broadly recognized that the gastroscopy is conducive to the early detection and diagnosis of gastrointestinal diseases, and it have been widely used to diagnose H. pylori infection. The proportion of H. pylori was higher among our study participants without gastric symptoms and digestive diseases, which might because the lack of clinical symptoms led to a lack of attention and delayed detection, diagnosis, and treatment of such diseases. The logistic regression analyses also revealed that a high incidence of H. pylori infection was associated with hyperlipidemia, with is largely consistent with previous research19. There is evidence to suggest that H. pylori infection stimulates the host to produce inflammatory factors and impairs lipid metabolism20, which then leads to increased triglyceride levels and decreased high-density lipoprotein cholesterol levels, thereby promoting dyslipidemia21.

While available treatment approaches to H. pylori include endoscopy and antibiotic therapy, there is evidence showing that the infection has developed resistance to many drugs, such as clarithromycin, Quinolones, and so forth13. Overall, antibiotic resistance of H. pylori has regional differences and rising trends, making the infection difficult to eradicate. In the present study, we conducted the qPCR to detect antibiotic resistance to clarithromycin and levofloxacin among the H. pylori-positive participants. In our study, antibiotic resistance of H. pylori to clarithromycin (48.92%) was found to be slightly higher than clarithromycin resistance in Yangzhou (41.0%), and levofloxacin resistance has no difference9. The resistance rate of clarithromycin and levofloxacin were lower than that in urban China (clarithromycin 50.83%, and levofloxacin 47.17%)1. Clarithromycin is a broad-spectrum antibiotic widely used to treat infections caused by a many bacteria, which has led to the emergence of bacterial resistance. Similarly, the broad application of levofloxacin against bacterial infections of the respiratory, urogenital and intestinal tract has led to antibiotic resistance.

The results of our univariate analysis of clarithromycin resistance revealed that low education level, shared tableware, and gastroscopy were risk factors for H. pylori infection. Specifically, the study participants with low education levels, sharing tableware, and requiring gastroscopy were more likely to ignore health problems and rely on taking medicine to relieve physical discomfort. By contrast, the study participants who had bedtime after 24:00, had unsure halitosis status, and consumed soybean and soy products were frequently less likely to develop clarithromycin resistance. These findings could be explained by the fact that younger, better educated and more health-aware people are less likely to develop resistance. Furthermore, many study participants found it difficult to respond to the question about their halitosis status, so many respondents chose to respond they were unsure about this point. Among the participants who were H. pylori positive, this result was weakly associated with clarithromycin resistance. H. pylori infection can affect the structure of the oral community and is related to a variety of oral diseases22, such as halitosis; however, from our results, it is difficult to determine whether halitosis is caused by H. pylori or by changes in the oral flora infected by H. pylori. Furthermore, as indicated in previous research, awareness of halitosis as diagnosed by a self-reported questionnaire is not always a reliable measure of the actual presence of halitosis23, suggesting that the relationship between halitosis and H. pylori resistance needs further detailed investigation. As concerns our finding regarding soy products, they contain essential nutrients and several other functional ingredients with demonstrated anti-inflammatory advantages and capacity to reduce the risk and severity of related diseases24. Soybean proteins can decrease serum total cholesterol and LDL cholesterol levels, while plant polyphenols in beans can prevent infection by pathogenic microorganisms25. In addition, high intake of soy products was found to be associated with a lower incidence of gastric cancer in people infected with H. pylori26. Similarly, our finding showing that soy diet is associated with reduced resistance of H. pylori could be attributed to isoflavones in soy products that can inhibit the growth of H. pylori and the activity of nuclear factor (NF)-κB27.

Furthermore, the results of our multivariate logistic analysis revealed that people sharing glasses and in the habit of consuming high-sugar foods and barbecued food were more likely to develop resistance. Previous studies confirmed the occurrence of intracellular H. pylori in yeast isolates from sugar-rich foods28, and H. pylori may improve survival through yeast vacuole sequestration29, which turns to resistance. In an animal study, the authors showed that high-fat diet changes the structure of intestinal flora, alters the intestinal metabolome, and promotes the development of antibiotic tolerance30. According to our results, people gathering and sharing tableware during the barbecue process also promoted the spread of H. pylori. In addition, former drinkers showed lower resistance, which might be associated with the change of microbiota. Alcohol is a risk factor for many diseases and can cause dysbiosis of oral and intestinal microbiota, thereby increasing increase intestinal permeability. This effect, as documented in several previous studies, can be reversed by stopping drinking and healthy diet31.

Furthermore, in our results, levofloxacin resistance showed similar trends compared to those observed with clarithromycin. Brushing teeth over 2 times per day was found to be a risk factor of levofloxacin resistance, as oral microbiota can carry antimicrobial resistance genes (ARGs). Due to its strong biofilm-disrupting ability, levofloxacin is used to treat and prevent dental-related problems. Oral microbiome metagenomics shows that many ARGs are located on mobile genetic elements, and are horizontally transferred within and between commensal bacteria32. In this respect, Blaustein et al. found that toothbrush metagenomes contained more ARGs than oral counterparts33. Accordingly, frequent dental hygiene was found to be negatively correlated with the diversity of microorganisms on toothbrushes, but positively correlated with resistance, which may be related to the frequent incorporation of oral microbiota carrying ARGs or an increase in the surrounding dust microbiota.

The present study has several limitations. First, we focused on the population in urban areas and Anxi County in Quanzhou, but no further division was made in the population classification, such as local population and floating population, which could have different dietary habits and lifestyle. Second, the questionnaire survey was based on the frequency of tea drinking, which has limitations in evaluating the impact of the strong tea culture and tea drinking habits of the people in Quanzhou on the incidence of H. pylori infection and antibiotic resistance. Furthermore, only H. pylori positive participants were tested for clarithromycin and levofloxacin resistance, and only two types of antibiotics were considered. Finally, our sample was rather limited, suggesting the need to analyze larger samples in further research.

Despite the aforementioned limitations, the present study provides valuable guidance for the prevention and treatment of H. pylori infection in the studied region.

Conclusion

Collectively, the results of the present study revealed a high prevalence of H. pylori in Quanzhou. While economic and social factors were not found to be associated with H. pylori infection, a significant effect was observed for education level and H. pylori resistance. Takeaway food was found to be a protective factor against H. pylori infection, and consumption of soy products was associated with a reduced risk of clarithromycin resistance. Furthermore, high sugar, spicy food, frequent tea drinking, and hyperlipidemia were found to be strongly associated with an increased risk of H. pylori infection. In addition, sharing tableware and water cups, high sugar, and frequent barbecue led to an increased risk of clarithromycin resistance, while the frequency of oral hygiene had an impact on levofloxacin resistance. Taken together, these results highlight the important role of diet, hygiene, and disease prevention awareness in H. pylori prevention and treatment. Finally, clarithromycin and levofloxacin resistance were found to be high in Quanzhou, suggesting the need to cautiously use antibiotics during H. pylori treatment.