Shifting Perspectives of Translational Research in Bio-Bactericides: Reviewing the Bacillus amyloliquefaciens Paradigm

Simple Summary

The continuous reduction of approved conventional microbicides, due to health concerns and the development of plant-pathogen resistance, has been urged for the use of safe alternatives in crop protection. Several beneficial bacterial species, termed biological control agents, are currently used in lieu of chemical pesticides. The approach to select such bacterial species and manufacture commercial products has been based on their biocontrol effect under optimal growth conditions, which is far from the real nutrient-limited field conditions of plant niches. It’s important to determine the complex interactions that occur among BCAs, plant host and niche microbiome to fully understand and exploit the potential of biological control agents. Furthermore, it’s crucial to acknowledge the environmental impact of their long-term use.

Abstract

Bacterial biological control agents (BCAs) have been increasingly used against plant diseases. The traditional approach to manufacturing such commercial products was based on the selection of bacterial species able to produce secondary metabolites that inhibit mainly fungal growth in optimal media. Such species are required to be massively produced and sustain long-term self-storage. The endpoint of this pipeline is large-scale field tests in which BCAs are handled as any other pesticide. Despite recent knowledge of the importance of BCA-host-microbiome interactions to trigger plant defenses and allow colonization, holistic approaches to maximize their potential are still in their infancy. There is a gap in scientific knowledge between experiments in controlled conditions for optimal BCA and pathogen growth and the nutrient-limited field conditions in which they face niche microbiota competition. Moreover, BCAs are considered to be safe by competent authorities and the public, with no side effects to the environment; the OneHealth impact of their application is understudied. This review summarizes the state of the art in BCA research and how current knowledge and new biotechnological tools have impacted BCA development and application. Future challenges, such as their combinational use and ability to ameliorate plant stress are also discussed. Addressing such challenges would establish their long-term use as centerfold agricultural pesticides and plant growth promoters.

Environmental Spread of Antibiotic Resistance

Antibiotic resistance represents a global health concern. Soil, water, livestock and plant foods are directly or indirectly exposed to antibiotics due to their agricultural use or contamination. This selective pressure has acted synergistically to bacterial competition in nature to breed antibiotic-resistant (AR) bacteria. Research over the past few decades has focused on the emergence of AR pathogens in food products that can cause disease outbreaks and the spread of antibiotic resistance genes (ARGs), but One Health approaches have lately expanded the focus to include commensal bacteria as ARG donors. Despite the attempts of national and international authorities of developed and developing countries to reduce the over-prescription of antibiotics to humans and the use of antibiotics as livestock growth promoters, the selective flow of antibiotic resistance transmission from the environment to the clinic (and vice-versa) is increasing. This review focuses on the mechanisms of ARG transmission and the hotspots of antibiotic contamination resulting in the subsequent emergence of ARGs. It follows the transmission of ARGs from farm to plant and animal food products and provides examples of the impact of ARG flow to clinical settings. Understudied and emerging antibiotic resistance selection determinants, such as heavy metal and biocide contamination, are also discussed here.

Bactericides Based on Copper Nanoparticles Restrain Growth of Important Plant Pathogens

Copper nanoparticles (CuNPs) can offer an alternative to conventional copper bactericides and possibly slow down the development of bacterial resistance. This will consequently lower the accumulation rate of copper to soil and water and lower the environmental and health burden imposed by copper application. Physical and chemical methods have been reported to synthesize CuNPs but their use as bactericides in plants has been understudied. In this study, two different CuNPs products have been developed, CuNP1 and CuNP2 in two respective concentrations (1500 ppm or 300 ppm). Both products were characterized using Dynamic Light Scattering, Transmission Electron Microscopy, Attenuated Total Reflection measurements, X-ray Photoelectron Spectroscopy, X-ray Diffraction and Scattering, and Laser Doppler Electrophoresis. They were evaluated for their antibacterial efficacy in vitro against the gram-negative species Agrobacterium tumefaciens, Dickeya dadantii, Erwinia amylovora, Pectobacterium carotovorum, Pseudomonas corrugata, Pseudomonas savastanoi pv. savastanoi, and Xanthomonas campestris pv. campestris. Evaluation was based on comparisons with two commercial bactericides: Kocide (copper hydroxide) and Nordox (copper oxide). CuNP1 inhibited the growth of five species, restrained the growth of P. corrugata, and had no effect in X. c. pv campestris. MICs were significantly lower than those of the commercial formulations. CuNP2 inhibited the growth of E. amylovora and restrained growth of P. s. pv. savastanoi. Again, its overall activity was higher compared to commercial formulations. An extensive in vitro evaluation of CuNPs that show higher potential compared to their conventional counterpart is reported for the first time and suggests that synthesis of stable CuNPs can lead to the development of low-cost sustainable commercial products.

A nutrient-limited screen unmasks rifabutin hyperactivity for extensively drug-resistant Acinetobacter baumannii

Industry screens of large chemical libraries have traditionally relied on rich media to ensure rapid bacterial growth in high-throughput testing. We used eukaryotic, nutrient-limited growth media in a compound screen that unmasked a previously unknown hyperactivity of the old antibiotic, rifabutin (RBT), against highly resistant Acinetobacter baumannii. In nutrient-limited, but not rich, media, RBT was 200-fold more potent than rifampin. RBT was also substantially more effective in vivo. The mechanism of enhanced efficacy was a Trojan horse-like import of RBT, but not rifampin, through fhuE, only in nutrient-limited conditions. These results are of fundamental importance to efforts to discover antibacterial agents.

Horizontal Gene Transfer of Antibiotic Resistance from Acinetobacter baylyi to Escherichia coli on Lettuce and Subsequent Antibiotic Resistance Transmission to the Gut Microbiome

Agricultural use of antibiotics is recognized by the U.S. Centers for Disease Control and Prevention as a major contributor to antibiotic-resistant infections. While most One Health attention has been on the potential for antibiotic resistance transmission from livestock and contaminated meat products to people, plant foods are fundamental to the food chain for meat eaters and vegetarians alike. We hypothesized that environmental bacteria that colonize plant foods may serve as platforms for the persistence of antibiotic-resistant bacteria and for horizontal gene transfer of antibiotic-resistant genes. Donor Acinetobacter baylyi and recipient Escherichia coli were cocultured in vitro, in planta on lettuce, and in vivo in BALB/c mice. We showed that nonpathogenic, environmental A. baylyi is capable of transferring plasmids conferring antibiotic resistance to E. coli clinical isolates on lettuce leaf discs. Furthermore, transformant E. coli from the in planta assay could then colonize the mouse gut microbiome. The target antibiotic resistance plasmid was identified in mouse feces up to 5 days postinfection. We specifically identified in vivo transfer of the plasmid to resident Klebsiella pneumoniae in the mouse gut. Our findings highlight the potential for environmental bacteria exposed to antibiotics to transmit resistance genes to mammalian pathogens during ingestion of leafy greens.IMPORTANCE Previous efforts have correlated antibiotic-fed livestock and meat products with respective antibiotic resistance genes, but virtually no research has been conducted on the transmission of antibiotic resistance from plant foods to the mammalian gut (C. S. Hölzel, J. L. Tetens, and K. Schwaiger, Pathog Dis 15:671-688, 2018, https://doi.org/10.1089/fpd.2018.2501; C. M. Liu et al., mBio 9:e00470-19, 2018, https://doi.org/10.1128/mBio.00470-18; B. Spellberg et al., NAM Perspectives, 2016, https://doi.org/10.31478/201606d; J. O'Neill, Antimicrobials in agriculture and the environment, 2015; Centers for Disease Control and Prevention, Antibiotic resistance threats in the United States, 2019). Here, we sought to determine if horizontal transmission of antibiotic resistance genes can occur between lettuce and the mammalian gut microbiome, using a mouse model. Furthermore, we have created a new model to study horizontal gene transfer on lettuce leaves using an antibiotic-resistant transformant of A. baylyi (AbzeoR).

Bacillus amyloliquefaciens strain MBI600 induces salicylic acid dependent resistance in tomato plants against Tomato spotted wilt virus and Potato virus Y

Plant growth promoting rhizobacteria have been proposed as effective biocontrol agents against several fungal and bacterial plant pathogens. However, there is limited knowledge regarding their effect against viruses. In this study, Bacillus amyloliquefaciens strain MBI600 (MBI600), active ingredient of the biological fungicide Serifel® (BASF SE), was tested for its antiviral action in tomato plants. Drench, foliar or soil amendment applications of MBI600 reduced up to 80% the incidence of Tomato spotted wilt virus under two different sets of environmental conditions. In addition, drench application of MBI600 delayed Potato virus Y systemic accumulation. Transcriptional analysis of a range of genes associated with salicylic acid (SA)- or jasmonic acid - related defense, priming or basal defense against viruses, revealed the induction of the SA signaling pathway in tomato after MBI600 treatment, and discrete gene expression patterns in plant response to TSWV and PVY infection.

The Effect of Silver Nanoparticles Size, Produced Using Plant Extract from Arbutus unedo, on Their Antibacterial Efficacy

Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaining minimal risk in development of bacterial resistance and human cell toxicity that conventional silver compounds exhibit. Several physical and chemical methods have been reported to synthesize AgNPs. However, these methods are expensive and involve heavy chemical reduction agents. An alternative approach to produce AgNPs in a cost-effective and environmentally friendly way employs a biological pathway using various plant extracts to reduce metal ions. The size control issue, and the stability of nanoparticles, remain some of the latest challenges in such methods. In this study, we used two different concentrations of fresh leaf extract of the plant Arbutus unedo (LEA) as a reducing and stabilizing agent to produce two size variations of AgNPs. UV-Vis spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy, and zeta potential were applied for the characterization of AgNPs. Both AgNP variations were evaluated for their antibacterial efficacy against the gram-negative species Escherichia coli and Pseudomonas aeruginosa, as well as the gram-positive species Bacillus subtilis and Staphylococcus epidermidis. Although significant differences have been achieved in the nanoparticles' size by varying the plant extract concentration during synthesis, the antibacterial effect was almost the same.

Effect of Pyraclostrobin Application on Viral and Bacterial Diseases of Tomato

Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally to their fungicide activity, to increase plant capacity to activate cellular defense responses and to promote plant growth. In this work, the effect of the QoI class fungicide pyraclostrobin was examined against Cucumber mosaic virus (CMV), Potato virus Y (PVY) and Pseudomonas syringae pv. tomato in tomato plants following artificial inoculation of the plants with the pathogens. Under controlled environmental conditions, pyraclostrobin delayed viral and bacterial disease development, even if P. syringae pv. tomato internal population levels were not affected significantly. In contrast, under field conditions in commercial greenhouses, a reduced CMV disease incidence throughout the tomato cultivation period was recorded. Gene expression analysis indicated an effect of pyraclostrobin application on tomato MAPKs transcript levels and a possible interference with plant stress responses.

Bacteria Murmur: Application of an Acoustic Biosensor for Plant Pathogen Detection

A multi-targeting protocol for the detection of three of the most important bacterial phytopathogens, based on their scientific and economic importance, was developed using an acoustic biosensor (the Quartz Crystal Microbalance) for DNA detection. Acoustic detection was based on a novel approach where DNA amplicons were monitored and discriminated based on their length rather than mass. Experiments were performed during real time monitoring of analyte binding and in a direct manner, i.e. without the use of labels for enhancing signal transduction. The proposed protocol improves time processing by circumventing gel electrophoresis and can be incorporated as a routine detection method in a diagnostic lab or an automated lab-on-a-chip system for plant pathogen diagnostics.

In silico analysis reveals multiple putative type VI secretion systems and effector proteins in Pseudomonas syringae pathovars

Type VI secretion systems (T6SS) of Gram-negative bacteria form injectisomes that have the potential to translocate effector proteins into eukaryotic host cells. In silico analysis of the genomes in six Pseudomonas syringae pathovars revealed that P. syringae pv. tomato DC3000, pv. tabaci ATCC 11528, pv. tomato T1 and pv. oryzae 1-6 each carry two putative T6SS gene clusters (HSI-I and HSI-II; HSI: Hcp secretion island), whereas pv. phaseolicola 1448A and pv. syringae B728 each carry one. The pv. tomato DC3000 HSI-I and pv. tomato T1 HSI-II possess a highly similar organization and nucleotide sequence, whereas the pv. tomato DC3000, pv. oryzae 1-6 and pv. tabaci 11528 HSI-II are more divergent. Putative effector orthologues vary in number among the strains examined. The Clp-ATPases and IcmF orthologues form distinct phylogenetic groups: the proteins from pv. tomato DC3000, pv. tomato T1, pv. oryzae and pv. tabaci 11528 from HSI-II group together with most orthologues from other fluorescent pseudomonads, whereas those from pv. phaseolicola, pv. syringae, pv. tabaci, pv. tomato T1 and pv. oryzae from HSI-I group closer to the Ralstonia solanacearum and Xanthomonas orthologues. Our analysis suggests multiple independent acquisitions and possible gene attrition/loss of putative T6SS genes by members of P. syringae.

Playing the "Harp": evolution of our understanding of hrp/hrc genes

With the advent of recombinant DNA techniques, the field of molecular plant pathology witnessed dramatic shifts in the 1970s and 1980s. The new and conventional methodologies of bacterial molecular genetics put bacteria center stage. The discovery in the mid-1980s of the hrp/hrc gene cluster and the subsequent demonstration that it encodes a type III secretion system (T3SS) common to Gram negative bacterial phytopathogens, animal pathogens, and plant symbionts was a landmark in molecular plant pathology. Today, T3SS has earned a central role in our understanding of many fundamental aspects of bacterium-plant interactions and has contributed the important concept of interkingdom transfer of effector proteins determining race-cultivar specificity in plant-bacterium pathosystems. Recent developments in genomics, proteomics, and structural biology enable detailed and comprehensive insights into the functional architecture, evolutionary origin, and distribution of T3SS among bacterial pathogens and support current research efforts to discover novel antivirulence drugs.

Engineered polyamine catabolism preinduces tolerance of tobacco to bacteria and oomycetes

Polyamine oxidase (PAO) catalyzes the oxidative catabolism of spermidine and spermine, generating hydrogen peroxide. In wild-type tobacco (Nicotiana tabacum 'Xanthi') plants, infection by the compatible pathogen Pseudomonas syringae pv tabaci resulted in increased PAO gene and corresponding PAO enzyme activities; polyamine homeostasis was maintained by induction of the arginine decarboxylase pathway and spermine was excreted into the apoplast, where it was oxidized by the enhanced apoplastic PAO, resulting in higher hydrogen peroxide accumulation. Moreover, plants overexpressing PAO showed preinduced disease tolerance against the biotrophic bacterium P. syringae pv tabaci and the hemibiotrophic oomycete Phytophthora parasitica var nicotianae but not against the Cucumber mosaic virus. Furthermore, in transgenic PAO-overexpressing plants, systemic acquired resistance marker genes as well as a pronounced increase in the cell wall-based defense were found before inoculation. These results reveal that PAO is a nodal point in a specific apoplast-localized plant-pathogen interaction, which also signals parallel defense responses, thus preventing pathogen colonization. This strategy presents a novel approach for producing transgenic plants resistant to a broad spectrum of plant pathogens.

The syndrome of gastric carcinoid and hyperparathyroidism: a family study and literature review

OBJECTIVE

To present evidence supporting the hypothesis that the coexistence of gastric carcinoids (GCs) and hyperparathyroidism may represent a distinct clinical entity, not related to multiple endocrine neoplasia type 1 (MEN1).

METHODS

We studied a cohort of five young siblings (age range 26-42 years), one of whom had been found to have GC and hyperparathyroidism. All siblings underwent serial gastroscopies for the assessment of gastric neuroendocrine cell proliferations over a mean follow-up period of 31.2 months. Imaging, biochemical and hormonal as well as molecular genetic investigations were performed in the direction of MEN1 syndrome. The literature was searched for cases with coexistence of GCs and hyperparathyroidism not associated with MEN1.

RESULTS

Four of the siblings, all male, were found to have GCs in a background of Helicobacter pylori-associated chronic atrophic gastritis and pernicious anaemia, with no serological evidence of gastric autoimmunity. In two of them, asymptomatic hyperparathyroidism was also present. Screening for MEN1 gene mutations or large deletions was negative, and hormone and imaging investigations did not support a diagnosis of familial MEN1 syndrome. A literature search revealed sporadic reports of cases with GC and hyperparathyroidism not attributable to MEN1.

CONCLUSIONS

The association of GCs and hyperparathyroidism appears to constitute a distinct syndrome that can be encountered in genetically predisposed individuals, and should not be regarded as 'atypical' or 'incomplete' expression of MEN1. Its prevalence and aetiology should be the subject of future studies. Screening for hyperparathyroidism seems to be justified in patients with GC of any type.

Cell wall chitosaccharides are essential components and exposed patterns of the phytopathogenic oomycete Aphanomyces euteiches

Chitin is an essential component of fungal cell walls, where it forms a crystalline scaffold, and chitooligosaccharides derived from it are signaling molecules recognized by the hosts of pathogenic fungi. Oomycetes are cellulosic fungus-like microorganisms which most often lack chitin in their cell walls. Here we present the first study of the cell wall of the oomycete Aphanomyces euteiches, a major parasite of legume plants. Biochemical analyses demonstrated the presence of ca. 10% N-acetyl-D-glucosamine (GlcNAc) in the cell wall. Further characterization of the GlcNAc-containing material revealed that it corresponds to noncrystalline chitosaccharides associated with glucans, rather than to chitin per se. Two putative chitin synthase (CHS) genes were identified by data mining of an A. euteiches expressed sequence tag collection and Southern blot analysis, and full-length cDNA sequences of both genes were obtained. Phylogeny analysis indicated that oomycete CHS diversification occurred before the divergence of the major oomycete lineages. Remarkably, lectin labeling showed that the Aphanomyces euteiches chitosaccharides are exposed at the cell wall surface, and study of the effect of the CHS inhibitor nikkomycin Z demonstrated that they are involved in cell wall function. These data open new perspectives for the development of antioomycete drugs and further studies of the molecular mechanisms involved in the recognition of pathogenic oomycetes by the host plants.

Pelvic floor study in patients with obstructive defecation: influence of biofeedback

The aim of this study was to evaluate the pathophysiologic abnormalities in patients with obstructive defecation or dyssynergia and to assess the role of biofeedback treatment. Three groups were studied. Group A had 24 patients with obstructive defecation; B, 25 patients with constipation; and C, 22 healthy volunteers. Rectosigmoid segmental transit time of group A was 28.5 hours (SD +/- 13.4); B, 17.2 hours (SD +/- 11.5); and C, 8.5 hours (SD +/- 6.3) (p < 0.05). There was no statistical difference in resting and squeezing anal pressure among the three groups. Anorectal angle at rest revealed no difference among the three groups. At strain, a statistically significant difference between groups A and C (p < 0.05) and a marginal difference between groups A and B was noted. Rectocele of the anterior rectal wall was present at strain in 17/24 patients of group A and 7/22 patients of group C (p < 0.05). Electromyography during strain revealed abnormal contractions of puborectalis muscle and external anal sphincter, in 13 and 14 patients of group A, respectively, which differed from that observed in groups B and C (p < 0.001). Biofeedback treatment was applied with good results in 7 of 11 patients of group A. At six months, constipation relapsed in only one of treated patients. Patients suffering from obstructive defecation seem to have slower rectosigmoid transit time than the others. Defecography shows smaller anorectal angle at strain and rectocele of the anterior rectal wall more often. Abnormal pelvic floor contraction at strain is often noted in anal electromyography. Some of these patients seem to respond favorably to biofeedback treatment.

"Reappearance" of Helicobacter pylori after eradication: implications on duodenal ulcer recurrence: a prospective 6 year study

We estimated the rate of Helicobacter pylori "reappearance" and of duodenal ulcer relapse up to 6 years after eradication of H. pylori. Of 220 patients in whom H. pylori was eradicated, 165 were eligible at 12 months to follow-up. Endoscopy was scheduled every 12 months or whenever symptoms appeared. Baseline H. pylori eradication was confirmed by CLO test, histology (hematoxylin-eosin and Giemsa stain), and culture. H. pylori was tested for by the three methods at 12 months and subsequently by 2 methods (CLO, histology) on biopsies obtained from the gastric antrum and body. We reviewed 90 patients after 1 year, 32 after 2 years, 13 after 3 years, 12 after 4 years, 2 after 5 years, and 16 after 6 years (range, 12 to 72 months; average, 25.23 months; patient-years, 347). At 12 months after eradication, 16 of 165 patients (9.7%) were H. pylori positive and 5 had ulcer relapse. Of 75 patients evaluated at 24 months, 7 (9.3%) were H. pylori positive and 1 (1.3%) had ulcer relapse. At 36 months, 43 patients were seen and 1 (2.3%) was H. pylori positive and had ulcer relapse (2.3%). Thirty, 18, and 16 patients were seen at 48, 60, and 72 months, respectively. None was H. pylori positive and none had ulcer relapse. Overall, 24 H. pylori-positive patients were found, two thirds of them in the first year after eradication. In 7 of 24 (29%, 6 smokers), ulcer recurred. None of the H. pylori-negative patients had ulcer relapse. The H. pylori reappearance rate was 7% and the ulcer relapse rate was 2% per patient-year. If the 16 H. pylori-positive patients who were found the first year are considered as recrudescence, then the reinfection rate will be 2.3% per patient-year.

One-week therapy with omeprazole, clarithromycin and metronidazole or ornidazole, followed by 3 weeks' treatment with omeprazole, eradicates Helicobacter pylori equally and heals duodenal ulcer

OBJECTIVE

To estimate and compare the efficacy of 'triple' 1-week regimens--omeprazole, clarithromycin and a nitroimidazole (metronidazole or ornidazole)--followed by omeprazole, for an additional 3 weeks, on Helicobacter pylori eradication and duodenal ulcer (DU) healing, in a country with a high resistance rate of H. pylori to metronidazole.

DESIGN

Open, prospective, two-centre study.

METHODS

Patients older than 18 years with active duodenal ulcer (DU), diagnosed by endoscopy and found to be infected with H. pylori (modified Giemsa stain and CLO test, Delta West, Australia), were included in the study. Three triple-drug regimens, given for 7 days, were used. (1) omeprazole (Om) 20 mg once a day, plus clarithromycin (Cl) 250 mg twice daily, plus ornidazole (Or) 500 mg twice daily (O1COr); (2) Om 20 mg twice daily, plus Cl 250 mg twice daily, plus Or 500 mg twice daily (OCOr); and (3) Om 20 mg twice daily, plus Cl 250 mg twice daily, plus metronidazole (M) 500 mg twice daily (OCM). Two hundred and three consecutive H. pylori-positive patients were included in the study, randomly assigned as follows: 50 patients (group A1: 32 men, 18 women, age 23-77 years) on O1COr; 47 patients (group A2: 29 men, 18 women, age 27-77 years) on OCOr; and 106 (group B: 71 men, 35 women, age 18-83 years) on OCM. Ulcer healing and H. pylori eradication were assessed endoscopically, 8-9 weeks after the start of treatment. H. pylori was considered eradicated if both histology and rapid urease test (six biopsies, antrum-body) were negative.

RESULTS

Eleven patients were lost to follow-up; 192 patients were analysed. Group A1: 48; group A2: 44; group B: 100. 'Per-protocol' analysis: H. pylori eradication, 90-93% (P = 0.901); ulcer healing, 90-98% (P = 0.300). 'Intention to treat' analysis: H. pylori eradication, 85-88% (P = 0.887); ulcer healing, 86-91% (P = 0.657). Compliance was excellent, no serious side effects were observed and no patients withdrew due to side effects.

CONCLUSIONS

No differences were observed in the H. pylori eradication and the healing rate among the groups. It seems that twice daily omeprazole is no better than single daily dosage and that ornidazole is as effective as metronidazole. In addition, in the studied population which is believed to have a high prevalence of metronidazole resistance, all the regimens used were effective.

Short-course therapy with amoxycillin-clarithromycin triple therapy for 10 days (ACT-10) eradicates Helicobacter pylori and heals duodenal ulcer. ACT-10 Study Group

BACKGROUND

Whilst the role of Helicobacter pylori eradication in managing duodenal ulcers has been established, consensus regarding the ideal regimen has not been achieved.

METHODS

Patients with H. pylori-positive active duodenal ulcer were randomly assigned to receive triple therapy with amoxycillin 1000 mg b.d. + clarithromycin 500 mg b.d. + omeprazole 20 mg daily for 10 days (ACT-10) or dual therapy with clarithromycin 500 mg t.d.s. + omeprazole 40 mg daily for 14 days (Dual). No additional acid suppression was provided following eradication therapy. Endoscopy, with biopsy for culture and histology, as well as 13C-urea breath testing (13C-UBT) were performed pre-treatment to assess H. pylori infection. H. pylori eradication was established at 4-6 weeks follow-up with culture (2 antral, 1 corpus biopsies), histology (2 antral biopsies), and 13C-UBT. Ulcer healing by endoscopy and change in clinical symptoms were also assessed at 4-6 weeks.

RESULTS

Two hundred and sixty-seven (267) patients were randomized to ACT-10 (n = 137) or Dual therapy (n = 130). By per-protocol and intention-to-treat analyses, H. pylori eradication at 4-6 weeks follow-up was 91% (115/127) and 88% (120/136), respectively, for ACT-10 patients and 59% (68/115) and 55% (72/130), respectively, for Dual therapy patients (P < 0.001 for both analyses). Ulcer healing was high in both treatment groups: ACT-10, 93% (118/127) and 90% (122/136), respectively; and Dual therapy, 91% (104/114) and 85% (111/130), respectively. Pre-treatment resistance to clarithromycin was low (4%, 8/214) as compared to metronidazole resistance which was over 40%. Emergence of resistance to clarithromycin was observed in 2% of patients receiving ACT-10 and in 25% of those receiving Dual therapy. ACT-10 and Dual therapy patients experienced similar rates of drug-related adverse events (33% vs. 32%, respectively) and discontinuation from therapy due to an adverse event (1.5% vs. 5%, respectively). More than 90% of patients were compliant with each prescribed medication.

CONCLUSION

In patients with active duodenal ulcer, a 10-day course of amoxycillin-clarithromycin-based triple therapy without additional acid suppression is highly effective in eradicating H. pylori and healing duodenal ulcer.

High eradication rate of Helicobacter pylori using a four-drug regimen in patients previously treated unsuccessfully

The objective of this study was to assess the efficacy of a new regimen in eradicating Helicobacter pylori (Hp) in patients with duodenal ulcer (DU) who were previously treated unsuccessfully with standard triple therapy (tripotassium dicitratobismuthate [TDB] 120 mg QID, metronidazole 500 mg TID, and tetracycline 500 mg QID) or proton-pump inhibitor (PPI) dual therapy (omeprazole 20 mg BID and amoxicillin 500 mg QID). The study included 133 consecutive patients aged 17 to 83 years with endoscopically diagnosed DU (diameter > or = 5 mm) in whom standard triple therapy or PPI dual therapy had failed to eradicate Hp. A rapid urease (CLO) test was performed on four biopsy specimens at study entry and at least 1 month after the end of treatment to confirm Hp colonization and eradication, respectively. Patients were considered to be Hp positive if any CLO test was positive within 2 hours, and Hp was considered to be eradicated if all CLO tests were still negative after 24 hours. In 31 randomly selected patients, Hp eradication was confirmed histologically as well. Patients were given omeprazole 60 mg/d (20 mg in the morning and 40 mg in the evening) plus amoxicillin 500 mg QID for 10 days and subsequently were given metronidazole 500 mg TID for 10 days plus TDB 120 mg QID for 6 weeks. One hundred and twenty-four patients were followed up; five (4%) withdrew because of side effects (protracted diarrhea, stomatitis, skin rashes). Per-protocol analysis showed Hp eradication in 113 of 119 patients (95%) and ulcer healing in 118 of 119 (99%). Intent-to-treat analysis showed an Hp eradication rate of 85% (113 of 133 patients) and an ulcer healing rate of 89% (118 of 133 patients). In per-therapy analysis, the Hp eradication rate was 91% (113 of 124 patients), and the ulcer healing rate was 95% (118 of 124 patients). Side effects were observed in 39 of 119 patients (33%) and were generally mild. The four-drug regimen used in this study, when given to patients previously treated unsuccessfully with standard triple therapy or PPI dual therapy, was highly effective in eradicating Hp and healing DUs and had no major side effects.

Helicobacter pylori infection in spouses of patients with duodenal ulcers and comparison of ribosomal RNA gene patterns

BACKGROUND

In recent studies, familial coinfection with the same Helicobacter pylori strains has been indicated, but more data are necessary to confirm intra-familial spread of the micro-organism.

AIMS

The aim of this study was (a) to assess the frequency of H pylori infection in spouses of patients with duodenal ulcers and (b) to investigate the possibility of intraspousal typing of the respective strains.

PATIENTS

Sixty four patients with duodenal ulcer and their spouses were included in the study.

METHODS

The H pylori infection was confirmed after endoscopy by culture and histological examination of biopsy specimens, and CLO test. The isolates were compared on the basis of their rRNA gene patterns (ribopatterns) after digestion of chromosomal DNA by the restriction endonucleases HaeIII or HindIII.

RESULTS

Of the patients, 54 were found to be H pylori positive. Of the respective spouses, 42 (78%) were also H pylori positive. In contrast, only two out of 10 (20%) partners of H pylori negative patients were infected. Ribopatterns of H pylori strains derived from 18 patients and their spouses showed that in each of eight couples a single strain had colonised both partners, while in the remaining 10 couples each partner was colonised by a distinct H pylori strain.

CONCLUSIONS

These data suggest person to person transmission within couples or exposure to a common source of infection.

The use of ERCP in the study of patients with hepatic echinococcosis before and after surgical intervention

BACKGROUND

Biliary tree involvement is the most common complication of hydatid liver disease, which is difficult to detect and manage.

METHODS

During the last 7 years, we examined by ERCP 26 cases with echinococcal liver involvement. Indications in the preoperative group included cholangitis in 6 cases, right-sided hypochondralgia involving 4, preoperative assessment in 4, and icterus in 1 case. In the postoperative group, the indications for ERCP were cholangitis in 5 cases, external biliary fistulas in 5, and biliary colic in 1 case.

RESULTS

ERCP findings in the preoperative group included external bile duct compression in 11 cases (73.3%), biliary fistula affecting 3 (20%), and echinococcal remnants within the common bile duct in 1 case (6.6%). With regard to the postoperative group, biliary fistula formation was detected in 6 cases (54.5%), echinococcal remnants within the common bile duct in 4 (36.3%), and external bile duct compression involving 1 case (9%). Endoscopic sphincterotomy was successfully performed in 13 patients in both groups. No serious complications were encountered.

CONCLUSION

ERCP is a safe and helpful preoperative or postoperative tool that aids in the diagnosis and often the treatment of echinococcal liver disease with involvement of the bile ducts.

Intraluminal duodenal diverticulum

A 76-year-old man with an iron deficiency anemia during the previous 4 years and recent melena was presented. Gastroscopy showed a sessile polypoid lesion in the area of the papilla of Vater and histology was normal. Barium swallow follow-through and CT scan revealed a round intraluminal filling defect. ERCP demonstrated extrinsic compression of both ducts. Emergency laparotomy was performed because of upper GI bleeding and because attempts at endoscopic haemostasis of the oozing polypoid mass were unsuccessful. A soft compressible polypoid mass was found, which on palpation excreted a viscous milky liquid through a tiny opening. Histology showed normal duodenal mucosa bilaterally, a diagnostic finding of intraluminal duodenal diverticulum. The atypical age of presentation as well as gastroscopic and roentgenographic findings of this rare entity are illustrated.

ABO blood group, secretor status and detection of Helicobacter pylori among patients with gastric or duodenal ulcers

Patients (454) referred for gastroscopy to the General Hospital of Athens were examined to determine (1) if non-secretors were over-represented among patients with ulcers and (2) if there was an association with ABO blood group or secretor status and carriage of Helicobacter pylori. Compared with the local population, among patients with either gastric ulcer (51) or duodenal ulcer (96) there was a significant increase in the proportion of those who were blood group O (P less than 0.025); however, there were no significant differences in the proportions of non-secretors. H. pylori was identified in 62% of the 454 patients: 59.5% of those without evidence of ulcers; 62.5% of those with gastric ulcer; 88% of those with duodenal ulcer (P less than 0.0005). These bacteria were cultured more often and in higher numbers from patients with duodenal ulcer (P less than 0.025). There was no association between ABO blood group and prevalence of H. pylori. The prevalence of H. pylori among non-secretors with gastric ulcer (12.5%) was significantly lower than that for non-secretors with duodenal ulcer (100%) (P less than 0.0005). This was not observed for secretors.

Seroepidemiology of Helicobacter pylori infection in Greece

Helicobacter pylori infection is strongly associated with chronic gastritis and peptic ulceration. As the prevalence of H. pylori infection in southern European populations is not known, a serological survey of 1069 samples from three different age groups in the Greek population was carried out with an enzyme-linked immunosorbent assay (ELISA) for antibodies to these bacteria. The antigen was an ultracentrifuged supernate of whole cell sonicates of 5 isolates of H. pylori assessed by electrophoresis and by immunoblotting with negative and positive sera. The sensitivity of the test was 97.43% and the specificity 100% for IgG antibodies; IgA and IgM antibodies to the antigen preparation were not found. Antibodies to H. pylori were detected among 39.4% of children aged 1-10 years, 67.1% of recruits (20-27 years) and 70% of blood donors (20-50 years). The prevalence of antibodies did not differ with sex in each of the age groups. The proportion of individuals with antibodies to H. pylori was higher in the younger age groups than those reported for similar age groups in western Europe.