Effect of the Short-Term Use of Fluoroquinolone and β-Lactam Antibiotics on Mouse Gut Microbiota

Microbiome's Universe: Impact on health, disease and cancer treatment

The human microbiome is a diverse ecosystem of microorganisms that reside in the body and influence various aspects of health and well-being. Recent advances in sequencing technology have brought to light microbial communities in organs and tissues that were previously considered sterile. The gut microbiota plays an important role in host physiology, including metabolic functions and immune modulation. Disruptions in the balance of the microbiome, known as dysbiosis, have been linked to diseases such as cancer, inflammatory bowel disease and metabolic disorders. In addition, the administration of antibiotics can lead to dysbiosis by disrupting the structure and function of the gut microbial community. Targeting strategies are the key to rebalancing the microbiome and fighting disease, including cancer, through interventions such as probiotics, fecal microbiota transplantation (FMT), and bacteria-based therapies. Future research must focus on understanding the complex interactions between diet, the microbiome and cancer in order to optimize personalized interventions. Multidisciplinary collaborations are essential if we are going to translate microbiome research into clinical practice. This will revolutionize approaches to cancer prevention and treatment.

Alterations in gut microbiota and inflammatory cytokines after administration of antibiotics in mice

Antibiotics are widely used to treat bacterial infection and reduce the mortality rate, while antibiotic overuse can cause gut microbiota dysbiosis. The impact of antibiotics on gut microbiota is not fully understood. In our study, four commonly used antibiotics (ceftazidime, cefoperazone-sulbactam, imipenem-cilastatin, and moxifloxacin) were given subcutaneously to mice, and their impacts on the gut microbiota composition and serum cytokine levels were evaluated through 16S rRNA analysis and a multiplex immunoassay. Antibiotic treatment markedly reduced gut microbiota diversity and changed gut microbiota composition. Antibiotic treatment significantly increased and decreased the abundance of Firmicutes and Bacteroidota, respectively. The antibiotic treatments increased the abundance of opportunistic pathogens such as Enterococcus and decreased that of Lachnospiraceae and Muribaculaceae. For moxifloxacin, the significantly high abundance of Enterococcus and Klebsiella was observed after 14 and 21 days of treatment. However, a relatively low abundance of opportunistic pathogens was found after 14 days of imipenem-cilastatin treatment. Additionally, the serum levels of various pro-inflammatory cytokines, such as IL-1β, IL-12 (p70), and IL-17, significantly increased after 21 days of antibiotic treatments. Overall, these results provide a guide for rational use of antibiotics in clinical settings: short-term use of moxifloxacin is recommended with regard to gut microbiota health, and the 14-day use of imipenem-cilastatin may have a less severe impact than other antibiotics.IMPORTANCEAntibiotic treatments are directly associated with changes in gut microbiota and are effective against both pathogens and beneficial bacteria. Gut microbiota dysbiosis induced by antibiotic treatment could increase the risk of some diseases. Therefore, an adequate understanding of gut microbiota changes after antibiotic use is crucial. In this study, we investigated the effects of continuous treatment with antibiotics on gut microbiota, serum cytokines, and intestinal inflammatory response. Our results suggest that short-term use of moxifloxacin is recommended, and the 14-day use of imipenem-cilastatin may have a less severe effect on gut microbiota health than cefoperazone-sulbactam. These results provide useful guidance on the rational use of antibiotics with regard to gut microbiota health.

A Gram-negative-selective antibiotic that spares the gut microbiome

Infections caused by Gram-negative pathogens are increasingly prevalent and are typically treated with broad-spectrum antibiotics, resulting in disruption of the gut microbiome and susceptibility to secondary infections1-3. There is a critical need for antibiotics that are selective both for Gram-negative bacteria over Gram-positive bacteria, as well as for pathogenic bacteria over commensal bacteria. Here we report the design and discovery of lolamicin, a Gram-negative-specific antibiotic targeting the lipoprotein transport system. Lolamicin has activity against a panel of more than 130 multidrug-resistant clinical isolates, shows efficacy in multiple mouse models of acute pneumonia and septicaemia infection, and spares the gut microbiome in mice, preventing secondary infection with Clostridioides difficile. The selective killing of pathogenic Gram-negative bacteria by lolamicin is a consequence of low sequence homology for the target in pathogenic bacteria versus commensals; this doubly selective strategy can be a blueprint for the development of other microbiome-sparing antibiotics.

Dietary nobiletin regulated cefuroxime- and levofloxacin-associated "gut microbiota-metabolism" imbalance and intestinal barrier dysfunction in mice

Nobiletin (NOB) exhibits significant biological activities and may be a potential dietary treatment for antibiotic-associated gut dysbiosis. In this study, mice were gavaged with 0.2 mL day-1 of 12.5 g L-1 cefuroxime (LFX) and 10 g L-1 levofloxacin (LVX) for a duration of 10 days, accompanied by 0.05% NOB to investigate the regulatory effect and potential mechanisms of NOB on antibiotic-induced intestinal microbiota disorder and intestinal barrier dysfunction. Our results indicated that dietary NOB improved the pathology of intestinal epithelial cells and the intestinal permeability by upregulating the expression of intestinal tight junction proteins (TJs) and the number of goblet cells. Furthermore, dietary NOB reduced the levels of serum lipopolysaccharide (LPS) and pro-inflammatory factors (TNF-α and IL-1β), thereby facilitating the restoration of the intestinal mucosal barrier. Additionally, dietary NOB increased the abundance of beneficial bacteria f_Lachnospiraceae and regulated the metabolic disorders of short-chain fatty acids (SCFAs) and bile acids (BAs). Notably, NOB supplementation resulted in elevated levels of butyric acid and lithocholic acid (LCA), which contributed to the repair of the intestinal mucosal barrier function and the maintenance of intestinal homeostasis. Collectively, our results propose a healthy dietary strategy for the prevention or mitigation of antibiotic-associated gut dysbiosis by dietary NOB.

Urinary antibiotic levels and risk of overweight/obesity in preschool children: A biomonitoring-based study from eastern China

There is limited evidence linking antibiotic exposure, particularly from contaminated food or drinking water, to childhood obesity. The study aimed to investigate the association between urinary antibiotic levels and overweight/obesity in preschool children. In the case-control study, 121 overweight/obese preschoolers and 242 controls (aged 3-6 years) from eastern China were enrolled in 2022 based on age, sex, and study site matching. Overweight/obesity was determined using body mass index (BMI) and weight for height (WFH) criteria derived from national data. A total of 50 antibiotics from 8 categories were analyzed using ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS). We identified major dietary patterns using principal component analysis (PCA) and examined the associations of antibiotic exposure with childhood overweight/obesity using multivariate logistic regression. Twenty-four individual antibiotics were detected in more than 10 % of the samples, and overall detection rates were up to 100 %. Overweight/obese children had a higher exposure to veterinary antibiotics (VAs) than normal weight children. PCA analysis showed that children who were overweight/obese had higher scores of "Aquatic products preferred dietary pattern" and "Cereals preferred dietary pattern" compared to children with normal weight. Multivariate logistic regression analyses indicated that exposure to elevated levels of deoxytetracycline (OR: 1.72; 95 %CI: 1.00-2.93) and quinolones (OR: 1.63; 95 %CI: 1.04-2.57) was significantly related to an increased risk of BMI-based overweight/obesity. Quinolones exposure was also significantly associated with WFH-based overweight/obesity, primarily in boys. After adjustment for all covariates, higher exposure to ofloxacin (of the quinolones) was significantly related to overweight/obesity in girls. Exposure to certain antibiotics, especially quinolones, may increase the risk of overweight/obesity in preschoolers. More prospective, well-designed studies are needed to clarify these findings.

The Role of Gut Microbiota in the Clinical Outcome of Septic Patients: State of the Art and Future Perspectives

Sepsis is a life-threatening multiple-organ dysfunction caused by a dysregulated host response to infection, with high mortality worldwide; 11 million deaths per year are attributable to sepsis in high-income countries. Several research groups have reported that septic patients display a dysbiotic gut microbiota, often related to high mortality. Based on current knowledge, in this narrative review, we revised original articles, clinical trials, and pilot studies to evaluate the beneficial effect of gut microbiota manipulation in clinical practice, starting from an early diagnosis of sepsis and an in-depth analysis of gut microbiota.

Dietary 5-demethylnobiletin prevents antibiotic-associated dysbiosis of gut microbiota and damage to the colonic barrier

5-Demethylnobiletin (5DN) is an important ingredient of citrus extract that is rich in polymethoxyflavones (PMFs). In this study, we systemically investigated the preventive effects of 5DN on antibiotic-associated intestinal disturbances. Experimental mice were gavaged 0.2 mL per day of the antibiotic cocktail (12.5 g L^-1 cefuroxime and 10 g L^-1 levofloxacin) for 10 days, accompanied by dietary 0.05% 5DN for 10 and 20 days. The results showed that the combination of cefuroxime and levofloxacin caused swelling of the cecum and injury to the colon tissue. Meanwhile, the balance of intestinal oxidative stress and the barrier function of mice was also damaged by the antibiotics through upregulation of the relative mRNA levels of superoxide dismutase 3 (SOD3), quinine oxidoreductase 1 (NQO1) and glutathione peroxidase 1 (GPX1), and downregulation of the relative protein levels of tight junction proteins (TJs). Moreover, antibiotic exposure led to disorder of the gut microbiota, particularly increased harmful bacteria (Proteobacteria) and decreased beneficial bacteria (Bacteroideta). However, dietary 5DN could reduce antibiotic-associated intestinal damage, evidenced by the results that 5DN alleviated gut oxidative damage and attenuated intestinal barrier injury via increasing the expression of TJs including occludin and zonula occluden1 (ZO1). Additionally, dietary 5DN modulated the composition of the gut microbiota in antibiotic-treated mice by increasing the relative levels of beneficial bacteria, such as Dubosiella and Lactobacillus. Moreover, PMFs increased the contents of isobutyric acid and butyric acid, which were almost eliminated by antibiotic exposure. In conclusion, 5DN could alleviate antibiotic-related imbalance of intestinal oxidative stress, barrier function damage, intestinal flora disorders and the reduction of short-chain fatty acids (SCFAs), which lays a foundation for exploring safer and more effective ways to prevent or mitigate antibiotic-associated intestinal damage.

Pharmacomicrobiomics in Pediatric Oncology: The Complex Interplay between Commonly Used Drugs and Gut Microbiome

The gut microbiome (GM) has emerged in the last few years as a main character in several diseases. In pediatric oncological patients, GM has a role in promoting the disease, modulating the effectiveness of therapies, and determining the clinical outcomes. The therapeutic course for most pediatric cancer influences the GM due to dietary modifications and several administrated drugs, including chemotherapies, antibiotics and immunosuppressants. Interestingly, increasing evidence is uncovering a role of the GM on drug pharmacokinetics and pharmacodynamics, defining a bidirectional relationship. Indeed, the pediatric setting presents some contrasts with respect to the adult, since the GM undergoes a constant multifactorial evolution during childhood following external stimuli (such as diet modification during weaning). In this review, we aim to summarize the available evidence of pharmacomicrobiomics in pediatric oncology.

Impact of COVID-19 and Antibiotic Treatments on Gut Microbiome: A Role for Enterococcus spp

OBJECTIVE

Several studies showed the substantial use of antibiotics and increased risk of antimicrobial resistant infections in patients with COVID-19. The impact of COVID-19-related treatments and antibiotics on gut dysbiosis has not been clarified.

DESIGN

The prospective cohort study included hospitalized COVID-19 patients (April-December 2020). The gut microbiome composition was analysed by 16S sequencing. The gut diversity and changes in opportunistic bacteria (OBs) or symbionts were analysed according to clinical parameters, laboratory markers of disease progression, type of non-antibiotic COVID-19 treatments (NACT) and type, WHO AWaRe group, and duration of antibiotic therapy (AT).

RESULTS

A total of 82 patients (mean age 66 ± 13 years, 70% males) were enrolled. The relative abundance of Enterococcus was significantly correlated with duration of hospitalization, intensive care unit stay, O2 needs, and D-dimer, ferritin, and IL-6 blood levels. The presence of Enterococcus showed the highest number of correlations with NACT, AT, and AT + NACT (e.g., hydroxychloroquine ± lopinavir/ritonavir) and increased relative abundance with AWaRe Watch/Reserve antibiotics, AT duration, and combinations. Abundance of Dorea, Agathobacter, Roseburia, and Barnesiella was negatively correlated with AT and corticosteroids use. Patients with increased IL-6, D-dimer, and ferritin levels receiving AT were more likely to show dysbiosis with increased abundance of Enterococcus and Bilophila bacteria and decreased abundance of Roseburia compared with those not receiving AT.

CONCLUSION

Microbiome diversity is affected by COVID-19 severity. In this context, antibiotic treatment may shift the gut microbiome composition towards OBs, particularly Enterococcus. The impact of treatment-driven dysbiosis on OBs infections and long-term consequences needs further study to define the role of gut homeostasis in COVID-19 recovery and inform targeted interventions.

Antibiotics in elderly Chinese population and their relations with hypertension and pulse pressure

Although antibiotic exposure in the general population has been well documented by a biomonitoring approach, epidemiologic data on the relationships between urinary antibiotic burden in the elderly with blood pressure (BP) are still lacking. The current study revealed thirty-four antibiotics in urine specimens from 990 elderly patients in Lu'an City, China, with detection frequencies ranging from 0.2 to 35.5%. Among the elderly, the prevalence of hypertension was 72.0%, and 12 antibiotics were detected in more than 10% of individuals with hypertension. The elderly with hypertension had the maximum daily exposure (5450.45 μg/kg/day) to fluoroquinolones (FQs). Multiple linear regression analyses revealed significant associations of BP and pulse pressure (PP) with exposure to specific antibiotics. The estimated β values (95% confidence interval) of associations with systolic blood pressure (SBP) in the right arm were 4.42 (1.15, 7.69) for FQs, 4.26 (0.52, 8.01) for the preferred as human antibiotics (PHAs), and 3.48 (0.20, 6.77) for the mixtures (FQs + tetracyclines [TCs] (tertile 3 vs. tertile 1)), respectively. Increased concentrations of TCs were associated with decreased diastolic BP (DBP; tertile 3: -1.75 [-3.39, -0.12]) for the right arm. Higher levels of FQs (tertile 3: 4.28 [1.02, 7.54]), PHAs (tertile 3: 4.25 [0.49, 8.01]), and FQs + TCs (tertile 3: 3.99 [0.71, 7.26]) were associated with increased SBP, and an increase in DBP for FQs (tertile 3: 1.82 [0.22, 3.42]) was shown in the left arm. Also, higher urinary concentrations of FQs (tertile 3: 3.18 [0.53, 5.82]), PHAs (tertile 3: 3.42 [0.40, 6.45]), and FQs + TCs (tertile 3: 3.06 [0.40, 5.72]) were related to increased PP, whereas a decline in PP for TCs (tertile 2: -2.93 [-5.60, -0.25]) in the right arm. And increased concentrations of penicillin V (tertile 3: 5.31 [1.53, 9.10]) and FQs + TCs (tertile 3: 2.84 [0.19, 5.49]) were related to higher PP in the left arm. By utilizing restricted cubic splines, our current study revealed a potential nonlinear dose-response association between FQ exposure and hypertension risk. In conclusion, this investigation is the first to present antibiotic exposure using a biomonitoring approach, and informs understanding of impacts of antibiotic residues, as emerging hazardous pollutants, on the hypertension risk in the elderly.

The Effect of Supplementation with Weizmannia coagulans Strain SANK70258 to Coccidia-Infected Broilers Is Similar to That of a Coccidiostat Administration

To determine whether it could also improve the production performance of Eimeria-infected broilers, Weizmannia coagulans strain SANK70258 (WC) supplementation was compared with coccidiostat lasalocid-A sodium (AM) administration. First, to determine the optimum WC dose, newly hatched broiler chick groups (n = 10) were untreated or consecutively given WC (0.005%, 0.01%, 0.03%, and 0.1%) and AM until slaughter (31 days of age). At day 21, all chicks were infected with coccidia. From the economical and practical viewpoints, 0.03% WC supplementation was the best dose. Second, newly hatched broiler chick groups (n = 10) were untreated or given 0.03% WC and AM. Each group was run in triplicate. At day 21, two chicks/pen with the farthest body weights as per the group’s mean body weight were spared, and the remaining inoculated with coccidia. At days 42 and 49, the WC and AM groups had significantly greater body weights and daily weight gains. Intestinal lesion scores were lower in 29-day-old AM and WC. Oocyst numbers were lower in 29- and 49-day-old AM and WC, but only 29- and 49-day-old AM had higher Escherichia coli levels. To conclude, although WC and AM induced similar growth performance in coccidium-infected chicks, unlike AM, the E. coli levels did not increase with WC.

Patients with Infections of The Central Nervous System Have Lowered Gut Microbiota Alpha Diversity

There are multiple lines of evidence for the existence of communication between the central nervous system (CNS), gut, and intestinal microbiome. Despite extensive analysis conducted on various neurological disorders, the gut microbiome was not yet analyzed in neuroinfections. In the current study, we analyzed the gut microbiome in 47 consecutive patients hospitalized with neuroinfection (26 patients had viral encephalitis/meningitis; 8 patients had bacterial meningitis) and in 20 matched for age and gender health controls. Using the QIIME pipeline, 16S rRNA sequencing and classification into operational taxonomic units (OTUs) were performed on the earliest stool sample available. Bacterial taxa such as Clostridium, Anaerostipes, Lachnobacterium, Lachnospira, and Roseburia were decreased in patients with neuroinfection when compared to controls. Alpha diversity metrics showed lower within-sample diversity in patients with neuroinfections, though there were no differences in beta diversity. Furthermore, there was no significant change by short-term (1-3 days) antibiotic treatment on the gut microbiota, although alpha diversity metrics, such as Chao1 and Shannon's index, were close to being statistically significant. The cause of differences between patients with neuroinfections and controls is unclear and could be due to inflammation accompanying the disease; however, the effect of diet modification and/or hospitalization cannot be excluded.

Effectiveness of modified Buzhong Yiqi decoction in treating myasthenia gravis: study protocol for a series of N-of-1 trials

Background

Myasthenia gravis (MG) is an acquired autoimmune disease with high heterogeneity. The disease is chronic, relapsing repeatedly and progressive with acute exacerbation occasionally. Although the treatment of MG has developed, it is still unsatisfactory and has some unexpected side effects. Traditional Chinese medicine (TCM) has shown great potential in MG treatment, including relief of muscle weakness syndrome, improvement of patient’s quality of life, and reduction of side effects of western medicine. The purpose of this study is to evaluate the effectiveness of modified Buzhong Yiqi decoction (MBYD) as an add-on therapy for MG through a small series of N-of-1 trials.

Methods

Single-centre, randomized, double-blind, 3 crossover N-of-1 trials will be conducted to enroll patients with MG diagnosed as spleen-stomach deficiency syndrome or spleen-kidney deficiency syndrome in TCM. Each N-of-1 trial has 3 cycles of two 4-week periods containing the MBYD period and placebo period. The wash-out interval of 1 week is prior to switching each period. Primary outcome: quantitative myasthenia gravis (QMG). Secondary outcomes: the following scales: myasthenia gravis composite (MGC), myasthenia gravis activities of daily living profile (MG-ADL), myasthenia gravis quality of life (MG-QOL); the level of CD4+FoxP3+Treg cells and cytokines (IL-4, IL-17A, INF-γ, TGF-β) in the peripheral blood; the alterations of the composition of gut microbiota; reduction of the side effects of western medicine.

Discussion

Used by WinBUGS software, we will conduct a hierarchical Bayesian statistical method to analyze the efficacy of MBYD in treating MG in individuals and populations. Some confounding variables such as TCM syndrome type and potential carryover effect of TCM will be introduced into the hierarchical Bayesian statistical method to improve the sensitivity and applicability of the trials, and the use of prior available information within the analysis may improve the sensitivity of the results of a series of N-of-1 trials, from both the individual and population level to study the efficacy of TCM syndrome differentiation. We assumed that this study would reveal that MBYD is effective for MG and provide robust evidence of the efficacy of TCM to treat MG.

Trial registration

Chinese Clinical Trial Register, ID: ChiCTR2000040477, registration on 29 November 2020.

Does Chemotherapy-Induced Gastrointestinal Mucositis Affect the Bioavailability and Efficacy of Anti-Infective Drugs?

Antimicrobial prophylaxis is increasingly being used in patients with hematological malignancies receiving high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT). However, few studies have focused on the potential impact of gastrointestinal mucositis (GI-M), a frequently observed side effect of chemotherapy in patients with cancer that affects the gastrointestinal microenvironment, on drug absorption. In this review, we discuss how chemotherapy leads to an overall loss of mucosal surface area and consequently to uncontrolled transport across the barrier. The barrier function is depending on intestinal luminal pH, intestinal motility, and diet. Another factor contributing to drug absorption is the gut microbiota, as it modulates the bioavailability of orally administrated drugs by altering the gastrointestinal properties. To better understand the complex interplay of factors in GI-M and drug absorption we suggest: (i) the longitudinal characterization of the impact of GI-M severity on drug exposure in patients, (ii) the development of tools to predict drug absorption, and (iii) strategies that allow the support of the gut microbiota. These studies will provide relevant data to better design strategies to reduce the severity and impact of GI-M in patients with cancer.

Lactobacillus reuteri BM53-1 Produces a Compound That Inhibits Sticky Glucan Synthesis by Streptococcus mutans

Cariogenic bacteria, such as Streptococcus (S.) mutans and S. sobrinus, produce insoluble and sticky glucans as a biofilm material. The present study demonstrates that a lactic acid bacterium (LAB) named BM53-1 produces a substance that inhibits the sticky glucan synthesis. The BM53-1 strain was isolated from a flower of Actinidia polygama and identified as Lactobacillus reuteri. The substance that inhibits sticky glucan synthesis does not exhibit antibacterial activity against S. mutans. The cariogenic S. mutans produces glucans under the control of three glucosyltransferase (GTF) enzymes, named GtfB, GtfC, and GtfD. Although GtfB and GtfC produce insoluble glucans, GtfD forms soluble glucans. Through quantitative reverse-transcriptional (qRT)-PCR analysis, it was revealed that the BM53-1-derived glucan-production inhibitor (GI) enhances the transcriptions of gtfB and gtfC genes 2- to 7-fold at the early stage of cultivation. However, that of gtfD was not enhanced in the presence of the GI, indicating that the glucan stickiness produced by S. mutans was significantly weaker in the presence of the GI. Our result demonstrates that Lb. reuteri BM53-1 is useful to prevent dental caries.

Antibiotic Therapy and the Gut Microbiome: Investigating the Effect of Delivery Route on Gut Pathogens

The contribution of the gut microbiome to human health has long been established, with normal gut microbiota conferring protection against invasive pathogens. Antibiotics can disrupt the microbial balance of the gut, resulting in disease and the development of antimicrobial resistance. The effect of antibiotic administration route on gut dysbiosis remains under-studied to date, with conflicting evidence on the differential effects of oral and parenteral delivery. We have profiled the rat gut microbiome following treatment with commonly prescribed antibiotics (amoxicillin and levofloxacin), via either oral or intravenous administration. Fecal pellets were collected over a 13-day period and bacterial populations were analyzed by 16S rRNA gene sequencing. Significant dysbiosis was observed in all treatment groups, regardless of administration route. More profound dysbiotic effects were observed following amoxicillin treatment than those with levofloxacin, with population richness and diversity significantly reduced, regardless of delivery route. The effect on specific taxonomic groups was assessed, revealing significant disruption following treatment with both antibiotics. Enrichment of a number of groups containing known gut pathogens was observed, in particular, with amoxicillin, such as the family Enterobacteriaceae. Depletion of other commensal groups was also observed. The degree of dysbiosis was significantly reduced toward the end of the sampling period, as bacterial populations began to return to pretreatment composition. Richness and diversity levels appeared to return to pretreatment levels more quickly in intravenous groups, suggesting convenient parenteral delivery systems may have a role to play in reducing longer term gut dysbiosis in the treatment of infection.