Aspirin inhibits the growth of Helicobacter pylori and enhances its susceptibility to antimicrobial agents

Consumption of non-antibacterial drugs may have negative impact on Helicobacter pylori colonization in the stomach

Background

Nineteen non-antibacterials were examined to show that their consumption for treatment of other diseases may inhibit Helicobacter pylori. Four antibiotics were used for comparison.

Materials and methods

Agar dilution method was used to examine the susceptibility of 20 H. pylori isolates to 4 antibiotics; metronidazole (MTZ), clarithromycin (CLR), amoxicillin (AMX), tetracycline (TET) and 19 non-antibacterials; proton pump inhibitors (PPIs), H2-blockers, bismuth subsalicylate (BSS), antifungals, statins, acetaminophen (ACE), aspirin (ASA), B-vitamins (B-Vits; Vit B1, Vit B6 and Vit Bcomplex) and vitamin C (Vit C). Blood agar plates were prepared with different concentrations of drugs and spot-inoculated with bacterial suspensions. Plates were incubated at 37 °C under microaerobic conditions and examined after 3-5 days. The isolate #20 that was mucoid and resistant to 19 drugs, including MTZ and SMV was tested against combined MTZ (8 μg/mL) and SMV (100 μg/mL). Results were analyzed statistically.

Results

Minimum inhibitory concentrations (MICs, μg/mL) of drugs and the frequency of susceptible H. pylori were determined as MTZ (8, 80%), CLR (2, 90%), AMX (1, 100%), TET (0.5, 70%), PPIs (8-128, 80%), H2-blockers (2000-8000, 75-80%), BSS (15, 85%), antifungals (64-256, 30-80%), statins (100-250, 35-90%), ACE (40, 75%), ASA (800, 75%), B-Vits (5000-20000, 80-100%) and Vit C (2048, 85%). Susceptibility of H. pylori isolates to 16 out of 19 non-antimicrobials (75-100%) was almost similar to those of antibiotics (70-100%) (P-value >0.05). The highest susceptibility rate (100%) belonged to Vit B1, Vit B6 and AMX. Out of 20 H. pylori isolates, 17 (85%) were susceptible to ≥13 non-antimicrobials and 3 (15%) were susceptible to < 13 (P-value <0.05). Mucoid H. pylori showed susceptibility to combination of MTZ and SMV.

Conclusions

Most of non-antibacterials inhibited H. pylori isolates, similar to antibiotics but their MICs exceeded those of antibiotics and their plasma concentrations. At low plasma concentration, non-antimicrobials may act as weak antibacterials, antibiotic adjuvants and immunostimulators.

Inhibition of Streptococcus mutans growth and biofilm formation through protein acetylation

Numerous cellular processes are regulated in response to the metabolic state of the cell, and one such regulatory mechanism involves lysine acetylation. Lysine acetylation has been proven to play an important role in the virulence of Streptococcus mutans, a major cariogenic bacterial species. S. mutans' glucosyltransferases (Gtfs) are responsible for synthesizing extracellular polysaccharides (EPS) and contributing to biofilm formation. One of the most common nonsteroidal anti-inflammatory drugs is acetylsalicylic acid (ASA), which can acetylate proteins through a nonenzymatic transacetylation reaction. Herein, we investigated the inhibitory effects of ASA on S. mutans. ASA treatment was observed to impede the growth of S. mutans, leading to a reduction in the production of water-insoluble EPS and the formation of biofilm. Moreover, ASA decreased the enzyme activity of Gtfs while increasing the protein acetylation level. The in vivo anticaries efficacy of ASA has further been proved using the rat caries model. In conclusion, ASA as an acetylation agent attenuated the cariogenic virulence of S. mutans, suggesting the potential value of protein acetylation on antimicrobial and anti-biofilm applications to S. mutans.

Salicylic acids and pathogenic bacteria: new perspectives on an old compound

Salicylic acids have been used in human and veterinary medicine for their anti-pyretic, anti-inflammatory, and analgesic properties for centuries. A key role of salicylic acid-immune modulation in response to microbial infection-was first recognized during studies of their botanical origin. The effects of salicylic acid on bacterial physiology are diverse. In many cases, they impose selective pressures leading to development of cross-resistance to antimicrobial compounds. Initial characterization of these interactions was in Escherichia coli, where salicylic acid activates the multiple antibiotic resistance (mar) operon, resulting in decreased antibiotic susceptibility. Studies suggest that stimulation of the mar phenotype presents similarly in closely related Enterobacteriaceae. Salicylic acids also affect virulence in many opportunistic pathogens by decreasing their ability to form biofilms and increasing persister cell populations. It is imperative to understand the effects of salicylic acid on bacteria of various origins to illuminate potential links between environmental microbes and their clinically relevant antimicrobial-resistant counterparts. This review provides an update on known effects of salicylic acid and key derivatives on a variety of bacterial pathogens, offers insights to possible potentiation of current treatment options, and highlights cellular regulatory networks that have been established during the study of this important class of medicines.

Bacteria in cancer initiation, promotion and progression

Cancer cells originate from a series of acquired genetic mutations that can drive their uncontrolled cell proliferation and immune evasion. Environmental factors, including the microorganisms that colonize the human body, can shift the metabolism, growth pattern and function of neoplastic cells and shape the tumour microenvironment. Dysbiosis of the gut microbiome is now recognized as a hallmark of cancer by the scientific community. However, only a few microorganisms have been identified that directly initiate tumorigenesis or skew the immune system to generate a tumour-permissive milieu. Over the past two decades, research on the human microbiome and its functionalities within and across individuals has revealed microbiota-focused strategies for health and disease. Here, we review the evolving understanding of the mechanisms by which the microbiota acts in cancer initiation, promotion and progression. We explore the roles of bacteria in gastrointestinal tract malignancies and cancers of the lung, breast and prostate. Finally, we discuss the promises and limitations of targeting or harnessing bacteria in personalized cancer prevention, diagnostics and treatment.

Association Between Aspirin Use and Gastric Adenocarcinoma: A Prospective Cohort Study

Prospective data examining the association of aspirin use, according to dose and duration, with long-term risk of gastric adenocarcinoma in non-Asian cohorts are lacking. We evaluated the association between aspirin use and risk of gastric adenocarcinoma in two large prospective U.S. cohort studies, the Nurses' Health Study and the Health Professionals Follow-up Study. Cox proportional hazards regression models were used to calculate multivariable adjusted HRs and 95% confidence intervals (CI). Among the 159,116 participants, we documented 316 gastric adenocarcinoma cases (176 women, 140 men) over 34 years encompassing 4.5 million person-years. Among women, regular aspirin use (at least two times or more per week) was significantly associated with lower risk of gastric adenocarcinoma (multivariable HR, 0.52; 95% CI, 0.37-0.73) compared with nonregular use. However, regular aspirin use was not associated with gastric adenocarcinoma risk among men (multivariable HR, 1.08; 95% CI, 0.77-1.52; Pheterogeneity for sex = 0.003). Among women, the lower risk of gastric adenocarcinoma was more apparent with increasing duration of aspirin use (Ptrend < 0.001) and more than five tablets per week (multivariable HR, 0.51; 95% CI, 0.31-0.84). Regular, long-term aspirin use was associated with lower risk of gastric adenocarcinoma among women, but not men. The benefit appeared after at least 10 years of use and was maximized at higher doses among women. The heterogeneity by sex in the association of aspirin use with risk of gastric adenocarcinoma requires further investigation.

PREVENTION RELEVANCE

Novel prevention is urgently needed to reduce incidence and mortality of gastric cancer. We found that regular aspirin use was associated with lower risk of gastric adenocarcinoma among women, but not men. The benefit appeared after at least 10 years of use and was maximized at higher doses among women. See related Spotlight, p. 213.

Role of Aspirin in Gastric Cancer Prevention

The role of aspirin in cancer prevention has been well described for multiple cancers, with strong data for gastrointestinal cancers. Studies, primarily conducted in colorectal cancer, suggest that aspirin exerts its cancer-preventive effects through the inhibition of gastrointestinal inflammation. Compared with colorectal cancer, the role of aspirin in gastric cancer prevention is less well described, however it stands to reason that aspirin and/or other nonsteroidal anti-inflammatory drugs may inhibit gastric cancer progression through the inhibition of COX-2. As discussed in this issue of Cancer Prevention Research, aspirin may prevent gastric cancer, albeit it appears to exert a disparate effect in men and women, the reason for which remain unclear. These results expand upon prior studies by prospectively examining aspirin use at a wider range of doses and durations in non-Asian participants and lend support to observations from previously conducted studies in Asian populations. See related article, p. 265.

Effect of Hybrid Type and Harvesting Season on Phytochemistry and Antibacterial Activity of Extracted Metabolites from Salix Bark

Hundreds of different fast-growing Salix hybrids have been developed mainly for energy crops. In this paper, we studied water extracts from the bark of 15 willow hybrids and species as potential antimicrobial additives. Treatment of ground bark in water under mild conditions extracted 12-25% of the dry material. Preparative high-performance liquid chromatography is proven here as a fast and highly efficient tool in the small-scale recovery of raffinose from Salix bark crude extracts for structural elucidation. Less than half of the dissolved material was assigned by chromatographic (gas chromatography and liquid chromatography) and spectroscopic (mass spectrometry and nuclear magnetic resonance spectroscopy) techniques for low-molecular-weight compounds, including mono- and oligosaccharides (sucrose, raffinose, and stachyose) and aromatic phytochemicals (triandrin, catechin, salicin, and picein). The composition of the extracts varied greatly depending on the hybrid or species and the harvesting season. This information generated new scientific knowledge on the variation in the content and composition of the extracts between Salix hybrids and harvesting season depending on the desired molecule. The extracts showed high antibacterial activity on Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 0.6-0.8 mg/mL; however, no inhibition was observed against Escherichia coli, Enterococcus faecalis, and Salmonella typhimurium. MIC of triandrin (i.e., 1.25 mg/mL) is reported for the first time. Although antibacterial triandrin and (+)-catechin were present in extracts, clear correlation between the antibacterial effect and the chemical composition was not established, which indicates that antibacterial activity of the extracts mainly originates from some not yet elucidated substances. Aquatic toxicity and mutagenicity assessments showed the safe usage of Salix water extracts as possible antibacterial additives.

Aspirin-Based Organoiron Dendrimers as Promising Anti-Inflammatory, Anticancer, and Antimicrobial Drugs

Designing nanocarriers with actions directed at a specific organ or tissue is a very promising strategy since it can significantly reduce the toxicity of a bioactive drug. In this study, an organometallic dendrimer was used to synthesize a biocompatible drug delivery system by attaching aspirin to the periphery of the dendrimer. Our goal is to enhance the bioavailability and anticancer activity of aspirin and reduce its toxicity through successive generations of organoiron dendrimers. The biological activity of aspirin-based dendrimer complexes was evaluated. The result of antimicrobial activity of the synthesized dendrimers also demonstrated an increase in their antimicrobial activity with increased generation of the dendrimers for most types of microorganisms. This study reveals for the first time that organoiron dendrimers linked with aspirin exhibit an excellent Gram-negative activity comparable to the reference drug Gentamicin. All synthesized dendrimers were tested for their anticancer activity against breast cancer cell lines (MCF-7), hepatocellular cell lines (Hep-G2), and a non-cancer cell line, Human Embryonic Kidney (HEK293), using the MTT cell viability assay and compared against a standard anticancer drug, Doxorubicin. Compounds G3-D9-Asp and G4-D12-Asp exhibited noticeable activity against both cell lines, both of which were more effective than aspirin itself. In addition, the in vivo anti-inflammatory activity and histopathology of swollen paws showed that the designed aspirin-based dendrimers displayed significant anti-inflammatory activity; however, G2-D6-Asp showed the best anti-inflammatory activity, which was more potent than the reference drug aspirin during the same period. Moreover, the coupling of aspirin to the periphery of organoiron dendrimers showed a significant reduction in the toxicity of aspirin on the stomach.

Chemoprevention Against Gastric Cancer

Gastric cancer is the fifth most common cause of cancer and the third leading cause of cancer-related deaths globally. The number of gastric cancer-related deaths is only projected to increase, attributable primarily to the expanding aging population. Prevention is a mainstay of gastric cancer control programs, particularly in the absence of accurate, noninvasive modalities for screening and early detection, and the absence of an infrastructure for this purpose in the majority of countries worldwide. Herein, we discuss the evidence for several chemopreventive agents, along with putative mechanisms. There remains a clear, unmet need for primary chemoprevention trials for gastric cancer.

Antibiofilm Activity of Diclofenac and Antibiotic Solutions in Endodontic Therapy

INTRODUCTION

The aim of this study was to compare the antibiofilm effects of a triple antibiotic solution (TAS); a double antibiotic solution (DAS); and 5%, 2.5%, and 1.25% diclofenac solutions (DCSs) against Enteroccocus faecalis biofilm.

METHODS

Eighty-four sterile radicular dentin blocks were used as biofilm substrate for 3 weeks. The study groups were as follows: (1) 1 mg/mL TAS (minocycline, metronidazole, and ciprofloxacin), (2) 1 mg/mL DAS (metronidazole and ciprofloxacin), (3) 5% DCS, (4) 2.5% DCS, (5) 1.25% DCS, and (6) 0.9% saline solution. The antimicrobial activity was evaluated by bacterial count determinations and confocal laser scanning microscopy. The contact time for the antimicrobial tests was 5 minutes. Bacterial counts were expressed as the reduction percentage of colony-forming units; for the confocal laser scanning microscopic evaluation, the log₁₀ total biovolume and percentage of green population (live cells) were calculated.

RESULTS

The colony-forming unit reduction percentage ranged between 62.98 and 98.62, respectively, for TAS and 5% DCS. The DCS showed a concentration-dependent effect.For the confocal laser scanning microscopy, the log₁₀ total biovolume in all groups was very similar and showed a scarce (1.39-1.02) but significant reduction with respect to the control; 5% and 2.5% DCSs gave the lowest viable cell percentage. The TAS and DAS groups showed intermediate values without significant differences between them.

CONCLUSIONS

DCSs at 5% and 2.5% have greater antimicrobial effects than TAS and DAS and may be considered a valid alternative for controlling the infection of teeth with apical periodontitis.

Aspirin Modulation of the Colorectal Cancer-Associated Microbe Fusobacterium nucleatum

Aspirin is a chemopreventive agent for colorectal adenoma and cancer (CRC) that, like many drugs inclusive of chemotherapeutics, has been investigated for its effects on bacterial growth and virulence gene expression. Given the evolving recognition of the roles for bacteria in CRC, in this work, we investigate the effects of aspirin with a focus on one oncomicrobe-Fusobacterium nucleatum We show that aspirin and its primary metabolite salicylic acid alter F. nucleatum strain Fn7-1 growth in culture and that aspirin can effectively kill both actively growing and stationary Fn7-1. We also demonstrate that, at levels that do not inhibit growth, aspirin influences Fn7-1 gene expression. To assess whether aspirin modulation of F. nucleatum may be relevant in vivo, we use the ApcMin/+ mouse intestinal tumor model in which Fn7-1 is orally inoculated daily to reveal that aspirin-supplemented chow is sufficient to inhibit F. nucleatum-potentiated colonic tumorigenesis. We expand our characterization of aspirin sensitivity across other F. nucleatum strains, including those isolated from human CRC tissues, as well as other CRC-associated microbes, enterotoxigenic Bacteroides fragilis, and colibactin-producing Escherichia coli Finally, we determine that individuals who use aspirin daily have lower fusobacterial abundance in colon adenoma tissues, as determined by quantitative PCR performed on adenoma DNA. Together, our data support that aspirin has direct antibiotic activity against F. nucleatum strains and suggest that consideration of the potential effects of aspirin on the microbiome holds promise in optimizing risk-benefit assessments for use of aspirin in CRC prevention and management.IMPORTANCE There is an increasing understanding of the clinical correlations and potential mechanistic roles of specific members of the gut and tumoral microbiota in colorectal cancer (CRC) initiation, progression, and survival. However, we have yet to parlay this knowledge into better CRC outcomes through microbially informed diagnostic, preventive, or therapeutic approaches. Here, we demonstrate that aspirin, an established CRC chemopreventive, exhibits specific effects on the CRC-associated Fusobacterium nucleatum in culture, an animal model of intestinal tumorigenesis, and in human colonic adenoma tissues. Our work proposes a potential role for aspirin in influencing CRC-associated bacteria to prevent colorectal adenomas and cancer, beyond aspirin's canonical anti-inflammatory role targeting host tissues. Future research, such as studies investigating the effects of aspirin on fusobacterial load in patients, will help further elucidate the prospect of using aspirin to modulate F. nucleatumin vivo for improving CRC outcomes.

Identification of aspirin and diclofenac binding proteins in the red complex pathogens

Red complex organisms are a group of organisms (Porphyromonas gingivalis ATCC 33277, Treponema denticola ATCC 35405, Tannerella forsythia ATCC 43037) that have been identified for the causation of periodontal diseases. Aspirin and diclofenac have been used as regular analgesics. Therefore, it is of interest to document the identification of aspirin and diclofenac binding proteins in the red complex pathogens using the STITCH v.5 pipeline. The virulence properties of these proteins were analyzed using VICMPred and VirulentPred software. Thus, we document 000 number of proteins having optimal binding features with the known analgesics.

Randomised clinical study: oral aspirin 325 mg daily vs placebo alters gut microbial composition and bacterial taxa associated with colorectal cancer risk

BACKGROUND

Aspirin is associated with decreased risk of colorectal cancer (CRC), potentially by modulating the gut microbiome.

AIMS

To evaluate the effect of aspirin on the gut microbiome in a double-blinded, randomised placebo-controlled pilot trial.

METHODS

Healthy volunteers aged 50-75 received a standard dose of aspirin (325 mg, N = 30) or placebo (N = 20) once daily for 6 weeks and provided stool samples every 3 weeks for 12 weeks. Serial measurements of gut microbial community composition and bacterial abundance were derived from 16S rRNA sequences. Linear discriminant analysis of effect size (LEfSe) was tested for between-arm differences in bacterial abundance. Mixed-effect regression with binomial distribution estimated the effect of aspirin use on changes in the relative abundance of individual bacterial taxa via an interaction term (treatment × time).

RESULTS

Over the study period, there were differences in microbial composition in the aspirin vs placebo arm. After treatment, four taxa were differentially abundant across arms: Prevotella, Veillonella, Clostridium XlVa and Clostridium XVIII clusters. Of pre-specified bacteria associated with CRC (n = 8) or aspirin intake (n = 4) in published studies, interactions were significant for four taxa, suggesting relative increases in Akkermansia, Prevotella and Ruminococcaceae and relative decreases in Parabacteroides, Bacteroides and Dorea in the aspirin vs placebo arm.

CONCLUSION

Compared to placebo, aspirin intake influenced several microbial taxa (Ruminococcaceae, Clostridium XlVa, Parabacteroides and Dorea) in a direction consistent with a priori hypothesis based on their association with CRC. This suggests that aspirin may influence CRC development through an effect on the gut microbiome. The findings need replication in a larger trial.

Interaction of glycated and acetylated human α2-antiplasmin with fibrin clots

: In type 2 diabetes mellitus (T2DM), increased α2-antiplasmin incorporation in fibrin and impaired fibrinolysis have been reported. Acetylsalicylic acid (ASA), used in cardiovascular prevention, modulates fibrinolysis and exerts weaker therapeutic effect in this disease. We investigated how glycation and acetylation of α2-antiplasmin affects its interaction with fibrin. Using surface plasmon resonance, we analyzed fibrin binding by α2-antiplasmin incubated with no β-D-glucose or ASA (control); incubated with β-D-glucose (5, 10, 50 mmol/l); (3) incubated with 1.6 mmol/l acetylsalicylic acid (ASA) and (4) incubated with 1.6 mmol/l ASA and 50 mmol/l β-D-glucose. Incubation with glucose decreased affinity of α2-antiplasmin for fibrin compared with control α2-antiplasmin in a glucose concentration-depending manner. α2-Antiplasmin incubation with ASA did not affect its affinity to fibrin. α2-Antiplasmin incubation with ASA and glucose resulted in 4.2-fold increased affinity to fibrin compared with α2-antiplasmin incubated with 50 mmol/l glucose (P < 0.001). In conclusion, α2-antiplasmin incubation with glucose at concentrations encountered in T2DM is associated with decreased binding affinity of α2-antiplasmin to fibrin. ASA alone does not affect the binding affinity of α2-antiplasmin to fibrin, but partly reverses the effect introduced by the incubation with 50 mmol/l glucose. This study suggests new mechanisms involved in regulating fibrinolysis efficiency in hyperglycemia.

Propranolol, chlorpromazine and diclofenac restore susceptibility of extensively drug-resistant (XDR)-Acinetobacter baumannii to fluoroquinolones

Nosocomial infections caused by extensively drug-resistant (XDR) or Pan-Drug resistant (PDR) Acinetobacter (A.) baumannii have recently increased dramatically creating a medical challenge as therapeutic options became very limited. The aim of our study was to investigate the antibiotic-resistance profiles and evaluate the various combinations of ciprofloxacin (CIP) or levofloxacin (LEV) with antimicrobial agents and non-antimicrobial agents to combat antimicrobial resistance of XDR A. baumannii. A total of 100 (6.25%) A. baumannii clinical isolates were recovered from 1600 clinical specimens collected from hospitalized patients of two major university hospitals in Upper Egypt. Antimicrobial susceptibility tests were carried out according to CLSI guidelines. Antimicrobial susceptibility testing of the respective isolates showed a high percentage of bacterial resistance to 19 antimicrobial agents ranging from 76 to99%. However, a lower percentage of resistance was observed for only colistin (5%) and doxycycline (57%). The isolates were categorized as PDR (2; 2%), XDR (68; 68%), and multi-drug resistant (MDR) (30; 30%). Genotypic analysis using ERIC-PCR on 2 PDR and 32 selected XDR isolates showed that they were not clonal. Combinations of CIP or LEV with antibiotics (including, ampicillin, ceftriaxone, amikacin, or doxycycline) were tested on these A. baumannii non-clonal isolates using standard protocols where fractional inhibitory concentrations (-FICs) were calculated. Results of the respective combinations showed synergism in 23.5%, 17.65%, 32.35%, 17.65% and 26.47%, 8.28%, 14.71%, 26.47%, of the tested isolates, respectively. CIP or LEV combinations with either chlorpromazine (CPZ) 200 μg/ml, propranolol (PR) in two concentrations, 0.5 mg/ml and 1.0 mg/ml or diclofenac (DIC) 4 mg/ml were carried out and the MIC decrease factor (MDF) of each isolate was calculated and results showed synergism in 44%, 50%, 100%, 100% and 94%, 85%, 100%, 100%, of the tested isolates, respectively. In conclusion, combinations of CIP or LEV with CPZ, PR, or DIC showed synergism in most of the selected PDR and XDR A. baumannii clinical isolates. However, these combinations have to be re-evaluated in vivo using appropriate animal models infected by XDR- or PDR- A. baumannii.

Non-antibiotics, Efflux Pumps and Drug Resistance of Gram-negative Rods

Non-antibiotic medicinal products consist of drugs with diverse activity against bacteria. Many non-antibiotics demonstrate direct anti-bacterial activity against Gram-positive cocci. The activity observed against Gram-negative rods is much lower and non-antibiotics primarily from the following groups: non-steroidal anti-inflammatory drugs, cardiovascular and antidepressant medicinal products demonstrate this activity. It has been shown that the low activity of some non-antibiotics or the absence of activity against Gram-negative rods is related, among other things, to the extrusion of these compounds from bacterial cells by multi-drug resistance efflux pumps. Substrates for the resistance-nodulation-division efflux systems include the following non-antibiotics: salicylate, diclofenac, ibuprofen, mefenamic acid, naproxen, amitriptyline, alendronate sodium, nicergoline, and ticlopidine. In addition, interactions between non-antibiotics and multi-drug resistance efflux pumps have been observed. It has also been revealed that depending on the concentration, salicylate induces expression of multi-drug resistance efflux pumps in Escherichia coli, Salmonella enterica subsp. enterica serotype Typhimurium, and Burkholderia cenocepacia. However, salicylate does not affect the expression of the resistance-nodulation-division efflux systems in Stenotrophomonas maltophilia and Acinetobacter baumannii. Most importantly, there were no effects of medicinal products containing some non-antibiotic active substances, except salicylate, as substrates of multi-drug resistance efflux pumps, on the induction of Gram-negative rod resistance to quinolones.

The effect of aspirin on antibiotic susceptibility

INTRODUCTION

Aspirin (acetylsalicylic acid, ASA) is often co-administered during the treatment of infections. Salicylic acid (SAL), the active metabolite of ASA, has significant effects on bacteria that might improve or (more likely) compromise the effectiveness of antibiotics. Areas covered: In this review, we summarize the interactions between SAL and antibiotics, and describe the underlying mechanisms involved. Expert opinion: In an era of rapidly increasing antibiotic resistance and lack of new antibiotic development, it is important to explore ways to optimize the effectiveness of antimicrobial treatment. This includes a better understanding of the interactions between commonly co-administered drugs. SAL might compromise the effectiveness of antibiotic treatment by inducing phenotypic resistance in bacteria. It can induce phenotypic resistance by up- or downregulating outer membrane proteins or efflux pumps, by upregulating antibiotic targets and by inducing enzymes with degrading activity. Moreover, SAL can increase the frequency of mutations leading to antibiotic resistance.

Prostaglandin E2 attenuates synergistic bactericidal effects between COX inhibitors and antibiotics on Staphylococcus aureus

PGE2 is found to attenuate the bactericidal effects of kanamycin or ampicillin in Staphylococcus aureus, as well as the methicillin-resistant S. aureus (MRSA). Co-treatment with cyclooxygenase (COX) inhibitors (celecoxib, aspirin or naproxen) synergistically enhances kanamycin or ampicillin-induced cell death of S. aureus and MRSA. COX inhibitors repressed bacterial multidrug resistance through down-regulating efflux pump activity in antibiotics-treated S. aureus and MRSA. However, this synergistic bactericidal effects are reduced by the treatment with PGE2. PGE2 restores the efflux pump activity as well as increases biofilm formation in S. aureus and MRSA. Collectively, the enhancement of efflux pump activity and biofilm formation with PGE2 might partially explain the resistance to synergistic bactericidal effects between COX inhibitors and antibiotics in PGE2-treated S. aureus.

In vitro antibacterial effects of Tanreqing injection combined with vancomycin or linezolid against methicillin-resistant Staphylococcus aureus

BACKGROUND

Combining conventional drugs and traditional medicine may represent a useful approach to combating antibiotic resistance, which has become a serious threat to global public health. This study aimed to evaluate the potential synergistic interactions between Tanreqing (TRQ) injection, a commercial traditional Chinese medicine formula used for the treatment of upper respiratory tract infection, and selected antibiotics used against methicillin-resistant Staphylococcus aureus (MRSA).

METHODS

The minimum inhibitory concentrations (MICs) of TRQ, vancomycin and linezolid against planktonic MRSA strain were determined by the broth microdilution method. The combined effects of TRQ and antibiotics were studied by the checkerboard method and the time-kill curve assay. The 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was employed to determine the inhibitory effect of the test compounds alone and in combination against MRSA embedded in biofilms.

RESULTS

MRSA strain was found to be susceptible to TRQ formula with MIC value 4125 μg/ml, while the MIC values for antibiotics, vancomycin and linezolid, were 2.5 μg/ml. The checkerboard analysis revealed that TRQ markedly enhanced activities of the tested antibiotics by reducing their MICs. In the time-kill analysis, TRQ at 1/2 × MIC in combination with vancomycin at 1/2 × MIC, as well as TRQ at 1/8 × MIC in combination with linezolid at 1/2 × MIC decreased the viable colonies by ≥2log10 CFU/ml, resulting in a potent synergistic effect against planktonic MRSA. In contrast to the tested antibiotics, which did not affect mature MRSA biofilms at subinhibitory concentrations, TRQ alone showed strong ability to disrupt preformed biofilms and induce biofilm cell death. The combination of TRQ with vancomycin or linezolid at sub-MIC concentrations resulted in a synergistic antibiofilm effect significantly higher than for each single agent.

CONCLUSIONS

This study provides the first in vitro evidence on the synergistic effects of TRQ and vancomycin or linezolid against planktonic and biofilm MRSA, and revealed their optimal combination doses, thereby providing a rational basis for the combination therapies against MRSA.

Aspirin and non-steroidal anti-inflammatory drugs use reduce gastric cancer risk: A dose-response meta-analysis

Background

The association between non-steroidal anti-inflammatory drugs (NSAIDs) and gastric cancer (GC) risk is controversial. The aim of this study is to evaluate the chemopreventive effect of NSAIDs for GC.

Methods

A literature search was performed for relevant studies using the PubMed and Embase database (up to March 2016). Risk ratios (RRs) and 95% confidence intervals (CIs) were used as the effect measures. The dose–response analysis and subgroup analysis were also performed.

Results

Twenty-four studies were included. Our results indicated that NSAIDs could reduce GC risk (any NSAIDs: RR=0.78, 96%CI=0.72-0.85; aspirin: RR=0.70, 95%CI=0.62-0.80; non-aspirin NSAIDs: RR=0.86, 95%CI=0.80-0.94), especially for non-cardia GC risk. Moreover, the dose-response analysis indicated the risk of GC decreased by 11% and 5% for 2 years increment of any NSAIDs and aspirin use, respectively. There were nonlinear relationships between the frequency of any NSAIDs use and aspirin use and GC risk (P for non-linearity<0.01), with a threshold effect of 5 times/week. A monotonically decreasing trend was observed only for the frequency of less than 5 times/week.

Conclusions

Our results indicate that NSAIDs is inversely associated with GC risk, especially for non-cardia GC risk. NSAIDs use may become a feasible approach to prevent GC.

Meloxicam inhibits biofilm formation and enhances antimicrobial agents efficacy by Pseudomonas aeruginosa

Microbial biofilms are communities of surface‐adhered cells enclosed in a matrix of extracellular polymeric substances. Bacterial cells in biofilm are 10~1,000‐fold more resistant to antimicrobials than the planktonic cells. Burgeoning antibiotic resistance in Pseudomonas aeruginosa biofilm has necessitated the development of antimicrobial agents. Here, we have investigated the antibiofilm effect of meloxicam against P. aeruginosaPAO1 and its potential mechanisms. Further, we have explored whether meloxicam could enhance the susceptibility of bacterial biofilms to treatment with conventional antimicrobials. Here, we found that meloxicam could significantly inhibit PAO1 biofilm formation in a dose‐dependent manner at the concentration without influence on planktonic cell growth. Meloxicam could also significantly inhibit the motilities, production of extracellular matrix, and expression of quorum sensing‐related genes and virulence factors of PAO1. Furthermore, synergistic interaction was observed when meloxicam combined with tetracycline, gentamicin, tobramycin, ciprofloxacin, ceftriaxone, ofloxacin, norfloxacin, ceftazidime, and DNase at subminimal inhibitory concentrations against PAO1 bioiflm. Collectively, our study lays the foundation for further investigation of repurposing meloxicam as a topical antibiofilm agent to treat P. aeruginosa biofilm‐related infections.

Synergistic effect of non-steroidal anti-inflammatory drugs (NSAIDs) on antibacterial activity of cefuroxime and chloramphenicol against methicillin-resistant Staphylococcus aureus

OBJECTIVES

Currently, only a few antibiotics are available to treat methicillin-resistant Staphylococcus aureus (MRSA). One alternative approach includes adjuvants to antibiotic therapy. Non-steroidal anti-inflammatory drugs (NSAIDs) are non-antibiotic drugs reported to exhibit antibacterial activity. The objective of this study was to investigate the interaction between NSAIDs with selected antibiotics (cefuroxime and chloramphenicol) against strains of S. aureus.

METHODS

The antibacterial activity of four NSAIDs (aspirin, ibuprofen, diclofenac and mefenamic acid) were tested against ten pathogenic bacterial strains using the microdilution broth method. The interaction between NSAIDs and antibiotics (cefuroxime/chloramphenicol) was estimated by calculating the fractional inhibitory concentration (FICI) of the combination.

RESULTS

Aspirin, ibuprofen and diclofenac exhibited antibacterial activity against the selected pathogenic bacteria. The interaction between ibuprofen/aspirin with cefuroxime was demonstrated to be synergistic against methicillin-sensitive S. aureus (MSSA) and the MRSA reference strain, whereas for MRSA clinical strains additive effects were observed for both NSAIDs and cefuroxime combinations. The combination of chloramphenicol with ibuprofen/aspirin was synergistic against all of the tested MRSA strains and displayed an additive effect against MSSA. A 4-8192-fold reduction in the cefuroxime minimum inhibitory concentration (MIC) and a 4-64-fold reduction of the chloramphenicol MIC were documented.

CONCLUSIONS

Overall, the NSAIDs ibuprofen and aspirin showed antibacterial activity against strains of S. aureus. Although individually less potent than common antibiotics, these NSAIDs are synergistic in action with cefuroxime and chloramphenicol and could potentially be used as adjuvants in combating multidrug-resistant MRSA.

Antimicrobial Effects of Antipyretics

Antipyretics are some of the most commonly used drugs. Since they are often coadministered with antimicrobial therapy, it is important to understand the interactions between these two classes of drugs. Our review is the first to summarize the antimicrobial effects of antipyretic drugs and the underlying mechanisms involved. Antipyretics can inhibit virus replication, inhibit or promote bacterial or fungal growth, alter the expression of virulence factors, change the surface hydrophobicity of microbes, influence biofilm production, affect the motility, adherence, and metabolism of pathogens, interact with the transport and release of antibiotics by leukocytes, modify the susceptibility of bacteria to antibiotics, and induce or reduce the frequency of mutations leading to antimicrobial resistance. While antipyretics may compromise the efficacy of antimicrobial therapy, they can also be beneficial, for example, in the management of biofilm-associated infections, in reducing virulence factors, in therapy of resistant pathogens, and in inducing synergistic effects. In an era where it is becoming increasingly difficult to find new antimicrobial drugs, targeting virulence factors, enhancing the efficacy of antimicrobial therapy, and reducing resistance may be important strategies.

Benzoate- and Salicylate-Tolerant Strains of Escherichia coli K-12 Lose Antibiotic Resistance during Laboratory Evolution

Escherichia coli K-12 W3110 grows in the presence of membrane-permeant organic acids that can depress cytoplasmic pH and accumulate in the cytoplasm. We conducted experimental evolution by daily diluting cultures in increasing concentrations of benzoic acid (up to 20 mM) buffered at external pH 6.5, a pH at which permeant acids concentrate in the cytoplasm. By 2,000 generations, clones isolated from evolving populations showed increasing tolerance to benzoate but were sensitive to chloramphenicol and tetracycline. Sixteen clones grew to stationary phase in 20 mM benzoate, whereas the ancestral strain W3110 peaked and declined. Similar growth occurred in 10 mM salicylate. Benzoate-evolved strains grew like W3110 in the absence of benzoate, in media buffered at pH 4.8, pH 7.0, or pH 9.0, or in 20 mM acetate or sorbate at pH 6.5. Genomes of 16 strains revealed over 100 mutations, including single-nucleotide polymorphisms (SNPs), large deletions, and insertion knockouts. Most strains acquired deletions in the benzoate-induced multiple antibiotic resistance (Mar) regulon or in associated regulators such as rob and cpxA, as well as the multidrug resistance (MDR) efflux pumps emrA, emrY, and mdtA Strains also lost or downregulated the Gad acid fitness regulon. In 5 mM benzoate or in 2 mM salicylate (2-hydroxybenzoate), most strains showed increased sensitivity to the antibiotics chloramphenicol and tetracycline; some strains were more sensitive than a marA knockout strain. Thus, our benzoate-evolved strains may reveal additional unknown drug resistance components. Benzoate or salicylate selection pressure may cause general loss of MDR genes and regulators.

IMPORTANCE

Benzoate is a common food preservative, and salicylate is the primary active metabolite of aspirin. In the gut microbiome, genetic adaptation to salicylate may involve loss or downregulation of inducible multidrug resistance systems. This discovery implies that aspirin therapy may modulate the human gut microbiome to favor salicylate tolerance at the expense of drug resistance. Similar aspirin-associated loss of drug resistance might occur in bacterial pathogens found in arterial plaques.

Nimesulide inhibits pathogenic fungi: PGE2-dependent mechanisms

Certain non-steroidal anti-inflammatory drugs can inhibit fungal growth, fungal prostaglandin E2 production, and enzyme activation. This study aims to investigate the antifungal effect of nimesulide against pathogenic filamentous fungi and yeast. The experiments detailed below were also designed to investigate whether the action is dependent on E2 fungal prostaglandins. Our data showed that nimesulide exhibited potent antifungal activity, mainly against Trichophyton mentagrophytes (ATCC 9533) and Cryptococcus neoformans with MIC values of 2 and 62 μg/mL, respectively. This drug was also able to inhibit the growth of clinic isolates of filamentous fungi, such as Aspergillus fumigatus, and dermatophytes, such as T. rubrum, T. mentagrophytes, Epidermophyton floccosum, Microsporum canis, and M. gypseum, with MIC values ranging from 112 to 770 μg/mL. Our data also showed that the inhibition of fungal growth by nimesulide was mediated by a mechanism dependent on PGE2, which led to the inhibition of essential fungal enzymes. Thus, we concluded that nimesulide exerts a fungicidal effect against pathogenic filamentous fungi and yeast, involving the inhibition of fungal prostaglandins and fungal enzymes important to the fungal growth and colonization.

Mismatch Repair and Colon Cancer: Mechanisms and Therapies Explored

Colorectal cancer (CRC) remains one of the most prevalent cancers worldwide. In sporadic CRC, mutations frequently occur in the DNA mismatch repair (MMR) pathway. In addition, germline MMR mutations have been linked to Lynch syndrome, the most common form of hereditary CRC. Although genetic mutations, diet, inflammation, and the gut microbiota can influence CRC, it is unclear how MMR deficiency relates to these factors to modulate disease. In this review, the association of MMR to the etiology of CRC is examined, particularly in the context of microRNAs (miRNAs), inflammation, and the microbiome. We also discuss the most current targeted therapies, methods of prevention, and molecular biomarkers against MMR-deficient CRC, all of which are encouraging advancements in the field.

The Influence of Efflux Pump Inhibitors on the Activity of Non-Antibiotic NSAIDS against Gram-Negative Rods

Background

Most patients with bacterial infections suffer from fever and various pains that require complex treatments with antibiotics, antipyretics, and analgaesics. The most common drugs used to relieve these symptoms are non-steroidal anti-inflammatory drugs (NSAIDs), which are not typically considered antibiotics. Here, we investigate the effects of NSAIDs on bacterial susceptibility to antibiotics and the modulation of bacterial efflux pumps.

Methodology

The activity of 12 NSAID active substances, paracetamol (acetaminophen), and eight relevant medicinal products was analyzed with or without pump inhibitors against 89 strains of Gram-negative rods by determining the MICs. Furthermore, the effects of NSAIDs on the susceptibility of clinical strains to antimicrobial agents with or without PAβN (Phe-Arg-β-naphtylamide) were measured.

Results

The MICs of diclofenac, mefenamic acid, ibuprofen, and naproxen, in the presence of PAβN, were significantly (≥4-fold) reduced, decreasing to 25–1600 mg/L, against the majority of the studied strains. In the case of acetylsalicylic acid only for 5 and 7 out of 12 strains of P. mirabilis and E. coli, respectively, a 4-fold increase in susceptibility in the presence of PAβN was observed. The presence of Aspirin resulted in a 4-fold increase in the MIC of ofloxacin against only two strains of E. coli among 48 tested clinical strains, which included species such as E. coli, K. pneumoniae, P. aeruginosa, and S. maltophilia. Besides, the medicinal products containing the following NSAIDs, diclofenac, mefenamic acid, ibuprofen, and naproxen, did not cause the decrease of clinical strains’ susceptibility to antibiotics.

Conclusions

The effects of PAβN on the susceptibility of bacteria to NSAIDs indicate that some NSAIDs are substrates for efflux pumps in Gram-negative rods. Morever, Aspirin probably induced efflux-mediated resistance to fluoroquinolones in a few E. coli strains.

Sublethal exposure to commercial formulations of the herbicides dicamba, 2,4-dichlorophenoxyacetic acid, and glyphosate cause changes in antibiotic susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium

Biocides, such as herbicides, are routinely tested for toxicity but not for sublethal effects on microbes. Many biocides are known to induce an adaptive multiple-antibiotic resistance phenotype. This can be due to either an increase in the expression of efflux pumps, a reduced synthesis of outer membrane porins, or both. Exposures of Escherichia coli and Salmonella enterica serovar Typhimurium to commercial formulations of three herbicides-dicamba (Kamba), 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate (Roundup)-were found to induce a changed response to antibiotics. Killing curves in the presence and absence of sublethal herbicide concentrations showed that the directions and the magnitudes of responses varied by herbicide, antibiotic, and species. When induced, MICs of antibiotics of five different classes changed up to 6-fold. In some cases the MIC increased, and in others it decreased. Herbicide concentrations needed to invoke the maximal response were above current food maximum residue levels but within application levels for all herbicides. Compounds that could cause induction had additive effects in combination. The role of soxS, an inducer of the AcrAB efflux pump, was tested in β-galactosidase assays with soxS-lacZ fusion strains of E. coli. Dicamba was a moderate inducer of the sox regulon. Growth assays with Phe-Arg β-naphtylamide (PAβN), an efflux pump inhibitor, confirmed a significant role of efflux in the increased tolerance of E. coli to chloramphenicol in the presence of dicamba and to kanamycin in the presence of glyphosate. Pathways of exposure with relevance to the health of humans, domestic animals, and critical insects are discussed.

IMPORTANCE

Increasingly common chemicals used in agriculture, domestic gardens, and public places can induce a multiple-antibiotic resistance phenotype in potential pathogens. The effect occurs upon simultaneous exposure to antibiotics and is faster than the lethal effect of antibiotics. The magnitude of the induced response may undermine antibiotic therapy and substantially increase the probability of spontaneous mutation to higher levels of resistance. The combination of high use of both herbicides and antibiotics in proximity to farm animals and important insects, such as honeybees, might also compromise their therapeutic effects and drive greater use of antibiotics. To address the crisis of antibiotic resistance requires broadening our view of environmental contributors to the evolution of resistance.

The impact of diclofenac and ibuprofen on biofilm formation on the surface of polypropylene mesh

PURPOSE

The difficulties related to treatment of deep surgical site infection involve formation of biofilm on the surface of synthetic material. It is considered that in treatment of infections involving formation of biofilm, concomitant therapy shall be applied covering anti-inflammatory drugs. The purpose of the work was to assess the impact of diclofenac and ibuprofen on bacterial biofilm formation on the surface of monofilament polypropylene mesh.

MATERIALS AND METHODS

The study involved 70 strains of Staphylococcus aureus and 70 strains of Escherichia coli isolated from different patients and those which differ with chromosomal DNA pattern within the species. The assessment of the impact of non-steroidal anti-inflammatory drugs (NSAIDs) on biofilm formation was carried out with the use of qualitative method (TTC reduction), quantitative (tenfold serial dilution) and with the use of scanning electron microscope (SEM).

RESULTS

In the qualitative assessment, after incubation in the medium containing NSAIDs statistically significant growth of S. aureus strain amount and E. coli which poorly make up biofilm was stated. Quantitative examination indicated characteristic decrease of the number of colony forming units in 1 ml of the suspension isolated from bacterial biofilm formed as a result of incubation of isolates in the medium with the addition of examined NSAIDs in comparison to biofilm from control regimen. In the examination with the use of SEM it was stated that the effect of isolates incubation in the medium with NSAIDs was decrease of the number of bacteria adjacent to the biomaterial surface.

CONCLUSIONS

Diclofenac and ibuprofen in the concentration obtained in the serum limit the formation of biofilm by S. aureus and E. coli.

Making bispirin: synthesis, structure and activity against Helicobacter pylori of bismuth(III) acetylsalicylate

Reaction of Bi(O(t)Bu)3 with aspirin (acetylsalicylic acid = aspH) in dry toluene results in the bismuth(III) complex, [Bi(O2C(C6H4)OAc)3]∞ 1 (O2C(C6H4)OAc = asp), minimum inhibitory concentration (MIC) against Helicobacter pylori ≥ 6.25 μg mL(-1), while the inclusion of a stoichiometric equivalent of KO(t)Bu leads to crystals of the bismuthate salt [KBi(O2C(C6H4)OAc)4]∞ 2.

Antibacterial Effect of Diclofenac Sodium on Enterococcus faecalis

OBJECTIVE

Non-steroidal anti-inflammatory drugs (NSAIDs) have shown antibacterial activity in some recent studies. The aim of this study was to evaluate the antibacterial effect of diclofenac against Enterococcus faecalis (E. faecalis) as a resistant endodontic bacterium in comparison with ibuprofen, calcium hydroxide and amoxicillin.

MATERIALS AND METHODS

The antibacterial activity of materials was evaluated using agar diffusion test and tube dilution method. Mixtures of 400 mg/ml of materials were prepared. The bacteria were seeded on 10 Muller-Hinton agar culture plates. Thirty microliter of each test material was placed in each well punched in agar plates. After incubation, the zone of bacterial inhibition was measured. Minimum inhibitory concentration (MIC) of the test materials was determined by agar dilution method. One-way Analysis of Variance (ANOVA) followed by Sidak post hoc test was used to compare the mean zone of microbial growth in the groups.

RESULTS

There were significant differences between the two groups (p< 0.05). Results of the agar diffusion test showed that antibiotics (amoxicillin, gentamycin) had the greatest antibacterial activity followed by NSAIDs (ibuprofen, diclofenac). Ca(OH)2 failed to show antibacterial activity. Diclofenac and ibuprofen showed distinct antibacterial activity against E. faecalis in 50 μg/ml and above concentrations.

CONCLUSION

Within the limitations of this in vitro study, it is concluded that diclofenac and ibuprofen have significantly more pronounced antibacterial activity against E. faecalis in comparison with Ca(OH)2.

Assessment of Helicobacter pylori eradication in patients on NSAID treatment

Background

In this post-hoc analysis of a randomized, double blind, placebo controlled trial, we measured the sensitivity and specificity of Helicobacter pylori IgG-antibody titer changes, hematoxylin and eosin (H&E) stains, immunohistochemical (IHC) stains and culture results in NSAID using patients, following H. pylori eradication therapy or placebo.

Methods

347 NSAID using patients who were H. pylori positive on serological testing for H. pylori IgG-antibodies were randomized for H. pylori eradication therapy or placebo. Three months after randomization, gastric mucosal biopsies were taken for H. pylori culture and histological examination. At 3 and 12 months, blood samples were taken for repeated serological testing. The gold standard for H. pylori infection was based on a positive culture or both a positive histological examination and a positive serological test. Sensitivity, specificity and receiver operating curves (ROC) were calculated.

Results

H. pylori eradication therapy was successful in 91% of patients. Culture provided an overall sensitivity of 82%, and 73% after eradication, with a specificity of 100%. Histological examination with either H&E or IHC stains provided sensitivities and specificities between 93% and 100%. Adding IHC to H&E stains did not improve these results. The ROC curve for percent change in H. pylori IgG-antibody titers had good diagnostic power in identifying H. pylori negative patients, with an area under the ROC curve of 0.70 (95 % CI 0.59 to 0.79, P = 0.085) at 3 months and 0.83 (95% CI 0.76 to 0.89, P < 0.0001) at 12 months. A cut-off point of at least 21% decrease in H. pylori IgG-antibody titers at 3 months and 58% at 12 months provided a sensitivity of 64% and 87% and a specificity of 81% and 74% respectively, for successful eradication of H. pylori.

Conclusions

In NSAID using patients, following H. pylori eradication therapy or placebo, histological examination of gastric mucosal tissue biopsies provided good sensitivity and specificity ratios for evaluating success of H. pylori eradication therapy. A percentual H. pylori IgG-antibody titer change has better sensitivity and specificity than an absolute titer change or a predefined H. pylori IgG-antibody titer cut-off point for evaluating success of H. pylori eradication therapy.

In vitro interactions between aspirin and amphotericin B against planktonic cells and biofilm cells of Candida albicans and C. parapsilosis

The increase in drug resistance and invasion caused by biofilm formation brings enormous challenges to the management of Candida infection. Aspirin's antibiofilm activity in vitro was discovered recently. The spectrophotometric method and the XTT {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide} reduction assay used for data generation make it possible to evaluate fungal biofilm growth accurately. The combined use of the most commonly used methods, the fractional inhibitory concentration index (FICI) and a newly developed method, the ΔE model, which uses the concentration-effect relationship over the whole concentration range instead of using the MIC index alone, makes the interpretation of results more reliable. As an attractive tool for studying the pharmacodynamics of antimicrobial agents, time-kill curves can provide detailed information about antimicrobial efficacy as a function of both time and concentration. In the present study, in vitro interactions between aspirin (acetylsalicylic acid [ASA]) and amphotericin B (AMB) against planktonic cells and biofilm cells of Candida albicans and C. parapsilosis were evaluated by the checkerboard microdilution method and the time-kill test. Synergistic and indifferent effects were found for the combination of ASA and AMB against planktonic cells, while strong synergy was found against biofilm cells analyzed by FICI. The ΔE model gave more consistent results with FICI. The positive interactions in concentration were also confirmed by the time-kill test. Moreover, this approach also revealed the pharmacodynamics changes of ASA and synergistic action on time. Our findings suggest a potential clinical use for combination therapy with ASA and AMB to augment activity against biofilm-associated infections.

Does long-term aspirin use have any effect on Helicobacter pylori eradication?

INTRODUCTION

Antimicrobial resistance has decreased eradication rates for Helicobacter pylori infection, and recent reports from different countries report eradication rates lower than 80% with triple therapy. The aim of this pilot study was to investigate the efficacy of standard triple eradication regimen in long-term aspirin users.

METHOD

The study population consisted of 77 aspirin using patients with dyspeptic symptoms and 79 age- and sex-matched dyspeptic patients without aspirin use as a control group. Both the study group and control patients were given lansoprazole (30 mg twice a day), clarithromycin (500 mg twice a day) and amoxicillin (1 g twice a day) (LCA) for 14 days as the eradication regimen. Patients on the study group were allowed to take aspirin during the eradication regimen (LCAAsp). Eradication was defined as the absence of H pylori as assessed with the C-urea breath test and H pylori stool antigen test 8 weeks after the end of the antimicrobial therapy.

RESULTS

The H pylori eradication rate in the LCAAsp group was 64/77 [83%, 95% confidence interval (CI): 79%-94%] with intention-to-treat (ITT) analysis and 64/75 (85%, 95% CI: 82%-96%) with per protocol (PP) analysis, and the H pylori eradication rate in the LCA group was 42/79 (53%, 95% CI: 43%-65%) with ITT analysis and 42/75 (56%, 95% CI: 46%-68%) with PP analysis. The difference between the groups both with ITT analysis and with PP analysis was statistically significant (P < 0.05).

CONCLUSION

These data suggest that H pylori eradication rate with standard triple eradication regimen is significantly higher among long-term aspirin users than in controls.

Efficacy of serology driven "test and treat strategy" for eradication of H. pylori in patients with rheumatic disease in the Netherlands

The treatment of choice of H. pylori infections is a 7-day triple-therapy with a proton pump inhibitor (PPI) plus amoxicillin and either clarithromycin or metronidazole, depending on local antibiotic resistance rates. The data on efficacy of eradication therapy in a group of rheumatology patients on long-term NSAID therapy are reported here. This study was part of a nationwide, multicenter RCT that took place in 2000-2002 in the Netherlands. Patients who tested positive for H. pylori IgG antibodies were included and randomly assigned to either eradication PPI-triple therapy or placebo. After completion, follow-up at 3 months was done by endoscopy and biopsies were sent for culture and histology. In the eradication group 13% (20/152, 95% CI 9-20%) and in the placebo group 79% (123/155, 95% CI 72-85%) of the patients were H. pylori positive by histology or culture. H. pylori was successfully eradicated in 91% of the patients who were fully compliant to therapy, compared to 50% of those who were not (difference of 41%; 95% CI 18-63%). Resistance percentages found in isolates of the placebo group were: 4% to clarithromycin, 19% to metronidazole, 1% to amoxicillin and 2% to tetracycline.

Low-dose aspirin delays gastric healing after Helicobacter pylori eradication

BACKGROUND AND AIM

Helicobacter pylori (H. pylori) and aspirin are the major causes of gastric injury, and eradication of H. pylori can restore mucosal injury such as gastric ulcer. The aim of the present study was to investigate the effects of low-dose aspirin on the healing process, determined by endoscopic features, after H. pylori eradication.

METHODS

From 2001 to 2008, 12,887 patients underwent endoscopic examination at our hospital. From these, 100 patients with and 100 patients without H. pylori infection were analyzed to identify the endoscopic features characteristic of H. pylori-infected stomach. Based on these characteristic features, we observed the healing process of 89 patients not taking low-dose aspirin and 12 patients taking low-dose aspirin for 6 months, 1 year, and 5 years, which was successful in eradicating H. pylori.

RESULTS

Diffuse redness (DR) of the fundic mucosa was the characteristic feature of H. pylori-infected stomach, whereas reddish streaks (RS) on the greater curvature of the antrum was the characteristic finding in non-infected stomach. In the no aspirin group, DR faded by 6 months and new expression of RS was observed 1 year after H. pylori eradication. In contrast, in the aspirin group, both fading of DR and the expression of RS were observed 5 years after eradication.

CONCLUSION

Low-dose aspirin delayed the early phase of the healing process in the gastric mucosa after H. pylori eradication.

[The trend of eradication rate of Helicobacter pylori infection and clinical factors that affect the eradication of first-line therapy]

BACKGROUND/AIMS

Although triple combination therapy containing a proton pump inhibitor (PPI) and two antibiotics is considered as a standard regimen for the first-line anti-Helicobacter pylori treatment, the recent trend of eradication rates following this therapy has been declined in the last few years. The purpose of this study was to investigate the trend of H. pylori eradication rates over the last 9 years and to evaluate are clinical factors affecting eradication rates.

METHODS

From January 2001 to June 2009, H. pylori eradication rates in 709 patients with documented H. pylori infection who received triple combination therapy for 7 days were retrospectively evaluated according to years and various clinical factors. H. pylori status was evaluated by 13C urea breath test 4-6 weeks after completion of treatment. results: The overall H. pylori eradication rate was 77.0%. The annual eradication rates from year 2001 to 2009 were 78.9%, 72.5%, 81.0%, 75.0%, 79.1%, 77.1%, 77.8%, 77.8%, and 75.0% by per-protocol analysis. There was no decreasing tendency of the eradiation rate over 9 years (p=0.974). There was no statistical difference in the eradication rates according to age, sex, smoking, alcohol, NSAIDs, underlying diseases, endoscopic diagnosis, and PPI. However, the eradication rate was lower in patients who took aspirin (OR=0.509, 95% CI=0.292-0.887, p=0.001) and antibiotics within 6 months (OR=0.347, 95% CI=0.183-0.658, p=0.001).

CONCLUSIONS

The H. pylori eradication rate has not changed at Gwangju-Chonnam province in Korea for recent 9 years. Lower eradication rate in aspirin and antibiotics users warrants further attention.

Potential role of the cardiovascular non-antibiotic (helper compound) amlodipine in the treatment of microbial infections: scope and hope for the future

The appearance of multiresistant bacterial strains coupled with the globally ongoing problem of infectious diseases point to the imperative need for novel and affordable antimicrobial drugs. The antibacterial potential of cardiovascular non-antibiotics such as amlodipine (AML), dobutamine, lacidipine, nifedipine and oxyfedrine has been reported previously. Of these drugs, AML proved to have the most significant antibacterial activity against Gram-positive and Gram-negative bacteria. Time-kill curve studies indicate that this Ca(2+) channel blocker exhibits bactericidal activity against Listeria monocytogenes and Staphylococcus aureus. AML could protect against murine listeriosis and salmonellosis at doses ranging within its maximum recommended human or non-toxic ex vivo dose. AML acts as a 'helper compound' in synergistic combination with streptomycin against several Gram-positive and Gram-negative bacterial strains in vitro as well as in the murine salmonellosis model in vivo. The present review focuses on the possible use of cardiovascular non-antibiotics such as AML as auxiliary compound targets for synergistic combinations in infections and hypertension conditions, rationalised on the basis of the activities of the compounds.

Aspirin use and the risk of gastric cancer: a meta-analysis

PURPOSE

Studies investigating the association between aspirin use and gastric cancer risk have reported conflicting results. The objective of this study was to quantitatively summarize the evidence for such a relationship.

RESULTS

Two investigators independently searched the Medline, PubMed, Embase, and Academic Search Premier (EBSCO) databases. Fourteen studies with a total number of 5,640 gastric cancer cases were identified. Most of the study populations were Caucasian. The combined results based on all studies showed there was no statistically significant difference between aspirin use and gastric cancer risk (odds ratio (OR) = 0.80, 95% confidence intervals (CI) = 0.54-1.19). When stratifying by study designs and gender, results were similar except for cohort and randomized controlled trial (RCT) studies (OR = 0.72, 95% CI = 0.62-0.84). When stratifying by location and Helicobacter pylori (H. pylori) infection, we observed there were lower risks in noncardia gastric cancer (OR = 0.62, 95% CI = 0.55-0.69) and H. pylori-infected individuals (OR = 0.62, 95% CI = 0.42-0.90) for aspirin users. Among Caucasians, there were lower risks for noncardia gastric cancer (OR = 0.73, 95% CI = 0.62-0.87) and H. pylori-infected individuals (OR = 0.62, 95% CI = 0.42-0.90) also.

CONCLUSIONS

This meta-analysis indicated that regular use of aspirin may be associated with reduced risk of noncardia gastric cancer, especially among Caucasians; for H. pylori-infected subjects the result was similar.

Effective reduction of gastric cancer risk with regular use of nonsteroidal anti-inflammatory drugs in Helicobacter pylori-infected patients

PURPOSE

Nonsteroidal anti-inflammatory drugs (NSAIDs) play protective roles in gastric carcinogenesis. However, the interaction between NSAIDs and Helicobacter pylori (H pylori) infection and the number needed to treat to prevent gastric cancer remains unclear.

PATIENTS AND METHODS

We conducted a nationwide retrospective cohort study based on data from the Taiwan National Health Insurance Database. Hospitalized patients with a primary diagnosis of peptic ulcer disease were selected. Overall, 52,161 patients were divided into non-NSAID user and regular NSAID user cohorts. Standardized incidence ratios (SIRs), cumulative incidences, and hazard ratios (HRs) were calculated.

RESULTS

Patients with peptic ulcers who never used NSAIDs had higher risk of gastric cancer compared with the general population (SIR, 2.11; 95% CI, 2.07 to 2.15), but regular NSAID use conferred lower risk (SIR, 0.79; 95% CI, 0.77 to 0.81). The protective role of NSAID use was observed in patients with gastric ulcer, but not in patients with non-H pylori-associated duodenal ulcer. On multivariate analysis, regular NSAID use was an independent protective factor for gastric cancer development (HR, 0.79 for each incremental year; P < .001), especially in H pylori-associated patients (HR, 0.52 for each incremental year; P < .001). Among patients with H pylori-infected gastric ulcers, the NNT to prevent a gastric cancer was 50.

CONCLUSION

Regular NSAID use may be a feasible way to prevent gastric cancer, at least in patients with gastric ulcers, and especially in H pylori-infected subjects.

Accuracy of rapid urease test in diagnosing Helicobacter pylori infection in patients using NSAIDs

BACKGROUND/AIM

This study aimed to determine the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the results of rapid urease test (RUT).

PATIENTS AND METHODS

The study evaluated 210 consecutive patients for the diagnosis of Helicobacter pylori (H. pylori) infection. They were divided into case and control groups based on history of NSAID use (n=70 each). Two biopsy specimens were collected from antrum and corpus of stomach during endoscopy and sent for rapid urease testing and histopathology. Sensitivity, specificity, and accuracy rate of RUT test were compared against histology.

RESULTS

The average age was 55.2+/-12.9 and 43.3+/-12.1 years in the case and control groups, respectively. Among NSAID users, RUT sensitivity, specificity and accuracy rate were all 100%. The sensitivity, specificity and accuracy rate of RUT in patients without history of NSAID use were 97.37, 98.57 and 98.14%, respectively. The overall sensitivity, specificity and accuracy rate of RUT were 98.57, 99.29, and 99.04%, respectively.

CONCLUSION

Our study shows that sensitivity, specificity and accuracy rate of RUT are not affected by NSAID use. Rapid urease test remains a reliable test for diagnosis of H. pylori in patients on NSAIDs.

Celecoxib inhibits Helicobacter pylori colonization-related factors

AIM: To investigate the effect of celecoxib, a selective COX-2 inhibitor, on Helicobacter pylori (H. pylori) colonization-related factors and its mechanism.

METHODS: After co-incubation with celecoxib, morphology of H. pylori strain 26695 was observed under a transmission electron microscope. Flagella motility was assessed by stab agar motility test. Adherence of H. pylori to AGS cells was determined by enzyme linked immunosorbent assay. Levels of mRNA expression in flagellar genes (flaA, flaB), urease genes (ureA, ureB) and adhesin genes (babA, sabA, alpA, alpB, hpaA, hopZ) were measured by real-time polymerase chain reaction.

RESULTS: Separation and non-integrity of bacterial cell wall, rarefaction and asymmetry of cytoplasm, and even lysis of H. pylori were observed in the presence of celecoxib. When H. pylori strains were incubated in the presence of celecoxib, their flagellar motility and adherence to AGS cells were inhibited. The expression of ureA, ureB, babA, sabA, alpA, alpB, hpaA, hopZ was up-regulated while the expression of flaA, flaB was down-regulated in the presence of celecoxib.

CONCLUSION: Celecoxib inhibits flagellar motility and adherence of H. pylori to AGS cells, and destructs their normal structure in vitro.