The discovery that Helicobacter pylori infection is the main cause of most gastroduodenal diseases has been a major breakthrough in gastroenterology It has dramatically changed the management of these diseases which are now considered as infectious diseases and are treated with antibiotics

Triple therapy, including two antibiotics, amoxicillin and clarithromycin, and a proton pump inhibitor given for a week has been recommended as the treatment of choice at several consensus conferences1–6 However, this treatment may fail for several reasons, as reported elsewhere7 In fact, the main reason for failure was found to be H pylori resistance to one of the antibiotics used (that is, clarithromycin) Other treatments have also been proposed, including metronidazole, a drug for which resistance is also a problem although to a lesser extent, as well as tetracycline, fluoroquinolones, and rifamycins for which resistance has become an emerging issue8,9

Our aim was to review the prevalence of H pylori resistance to these various antibiotics, their clinical importance, and methods of testing, especially in light of the resistance mechanism which allows application of molecular methods

Numerous studies have been performed to determine the prevalence of H pylori resistance to antibiotics However, many of them have drawbacks, in particular concerning the number and representativeness of the strains tested

Most of the studies were performed in specialised centres, with recruitment of special cases which are not always representative of patients as a whole and, because these studies are monocentric, the number of patients may be low, leading to wide confidence intervals of the prevalence rates obtained

Ideal studies involving patients who are representative of a given region are few An alternative has been to analyse prevalence data obtained from clinical trials aiming to evaluate new regimens As prevalence is in essence an evolving phenomenon, only …

https://gut.bmj.com/content/gutjnl/53/9/1374.full.pdf

H pylori antibiotic resistance: prevalence, importance, and advances in testing

Gastroretentive dosage forms: Overview and special case of Helicobacter pylori

Clinicians use many terms including undulating myokymia, neuromyotonia, Isaacs’ syndrome and Cramp–Fasciculation Syndrome to describe the motor manifestations of generalized peripheral nerve hyperexcitability (PNH). Our previous findings in a selected group of patients with undulating myokymia or neuromyotonia, and EMG doublet or multiplet (‘myokymic’) motor unit discharges, indicated that an autoantibody‐mediated potassium channelopathy was likely to be the cause of their disorder. This prompted us to search for a common pathogenesis in a wider spectrum of PNH syndromes. We studied the clinical, autoimmune and electrophysiological features of 60 patients presenting with acquired PNH. Patients were grouped according to an EMG criterion: the presence (group A, n  = 42) or absence (group B, n  = 18) of doublet or multiplet myokymic motor unit discharges. The average ages of onset in the two groups were 45 and 48 years respectively. The relative frequency and topography of the clinical features were similar in both groups. Serum voltage‐gated potassium channel (VGKC) antibodies were detected using a 125I‐α‐dendrotoxin immunoprecipitation assay in 38% of group A and in 28% of group B. Autoimmune disease and other autoantibodies were present in both groups more frequently than would be expected by chance (59 and 28%, respectively)—particularly myasthenia gravis and acetylcholine receptor (AChR) antibodies. The neurological disorder in both groups could occur as a paraneoplastic condition. Thymoma was detected in 19 and 11%, respectively, and lung cancer in 10 and 6%, respectively. An axonal neuropathy was present in six (14%) of group A and in one (6%) of group B patients. Thus, despite the discrete EMG distinction, both groups share clinical features often associated with autoimmune‐related diseases, which can occur as paraneoplastic disorders and, importantly, have an increased frequency of VGKC antibodies. We conclude that autoimmunity, and specifically VGKC antibodies in many cases, are strongly implicated in the pathogenesis of both groups, and that the EMG features reflect quantitative rather than qualitative differences between the diverse clinical syndromes. These findings also have relevance for disease management. A classification is proposed that distinguishes immune‐mediated PNH (irrespective of whether VGKC antibodies are detectable by standard assays) from non‐immune forms of PNH that include toxins, anterior horn cell degeneration in motor neurone disease and genetic disorders.

/pdf/phenotypic-variants-of-autoimmune-peripheral-nerve-7r0u922tse.pdf

Phenotypic variants of autoimmune peripheral nerve hyperexcitability

https://www.gastrojournal.org/article/S0016-5085(02)00119-1/pdf

Importance of Helicobacter pylori oipA in clinical presentation, gastric inflammation, and mucosal interleukin 8 production

Under stress conditions, many species of bacteria enter into starvation mode of metabolism or a physiologically viable but non-culturable (VBNC) state. Several human pathogenic bacteria have been reported to enter into the VBNC state under these conditions. The pathogenic VBNC bacteria cannot be grown using conventional culture media, although they continue to retain their viability and express their virulence. Though there have been debates on the VBNC concept in the past, several molecular studies have shown that not only can the VBNC state be induced under in vitro conditions but also that resuscitation from this state is possible under appropriate conditions. The most notable advance in resuscitating VBNC bacteria is the discovery of resuscitation-promoting factor (Rpf), which is a bacterial cytokines found in both Gram-positive and Gram-negative organisms. VBNC state is a survival strategy adopted by the bacteria, which has important implication in several fields, including environmental monitoring, food technology, and infectious disease management; and hence it is important to investigate the association of bacterial pathogens under VBNC state and the water/foodborne outbreaks. In this review, we describe various aspects of VBNC bacteria, which include their proteomic and genetic profiles under the VBNC state, conditions of resuscitation, methods of detection, antibiotic resistance, and observations on Rpf.

/pdf/current-perspectives-on-viable-but-non-culturable-vbnc-2pzp9lrq93.pdf

Current Perspectives on Viable but Non-Culturable (VBNC) Pathogenic Bacteria.

BACKGROUND Studies in Western populations suggest that cagA, iceA, and vacA gene status in Helicobacter pylori isolates is associated with increased virulence and peptic ulcer disease. AIM To investigate the relationship between peptic ulcer and expression of Lewis (Le) antigens as well as cagA, iceA, and vacA in H pylori isolates in Singapore. METHODS Expression of Le antigens in H pylori isolates obtained from patients with dyspepsia was measured by enzyme linked immunosorbent assay. The cagA, iceA, and vacA status was determined by polymerase chain reaction. RESULTS Of 108 H pylori isolates, 103 (95.4%) expressed Le x and/or Le y , while Le a and Le b were expressed in 23 (21.3%) and 47 (43.5%) isolates, respectively. Expression of two or more Le antigens (Le x , Le y , Le a , or Le b ) was significantly higher in H pylori isolated from ulcer patients than in non-ulcer patients (89.6% v 73.2%, p=0.035). There were no significant differences in the prevalence of cagA or iceA 1 in H pylori isolates from peptic ulcer and non-ulcer patients (86.6% v 90.2% for cagA ; 70.1% v 68.3% for iceA 1), and no association of peptic ulcer with any specific vacA genotype. CONCLUSIONS The present study indicates that peptic ulcer disease is associated with increased expression of Lewis antigens but not cagA, iceA, or vacA genotype in H pylori isolates in our population. This suggests that cagA, iceA, and vacA are not universal virulence markers, and that host-pathogen interactions are important in determining clinical outcome.

https://gut.bmj.com/content/gutjnl/47/1/18.full.pdf

Association of peptic ulcer with increased expression of Lewis antigens but not cagA, iceA, and vacA in Helicobacter pylori isolates in an Asian population

Helicobacter pylori was grown on solid medium for up to 5 weeks. Morphological conversion from spiral to coccoid forms began after 7 days incubation under microaerophilic conditions. Similar to the exponential cultures, the ageing bacteria produced alkaline phosphatase, acid phosphatase, leucine arylamidase and naphthol-AS-beta 1-phosphohydrolase, although there was a reduction in the levels of the latter two enzymes. Unlike the other enzymes, urease was not detected in 5-week-old cultures. By using primers based on urease subunit C and 26 kD protein genes for polymerase chain reaction (PCR) these two important gene fragments remained conserved despite the morphological conversion from spiral to coccoid forms. Furthermore, PCR-based random amplified polymorphic DNA (RAPD) fingerprinting showed similar DNA banding patterns from bacteria of various ages, demonstrating the conservation of the DNA composition despite morphological changes. This study shows that the aging coccoid form of H. pylori, although reportedly non-culturable in vitro, remains genetically unchanged indicating that it is likely to be viable.

Is the coccoid form of Helicobacter pylori viable

AIM: To study the agglutination pattern of Helicobacter pylori coccoid and spiral forms.

METHODS: Assays of agglutination and agglutination inhibition were applied using fifteen commercial lectins.

RESULTS: Strong agglutination was observed with mannose-specific Concanavalin A (Con A), fucose-specific Tetragonolobus purpureas (Lotus A) and N-acetyl glucosamine-specific Triticum vulgaris (WGA) lectins. Mannose and fucose specific lectins were reactive with all strains of H. pylori coccoids as compared to the spirals. Specific carbohydrates, glycoproteins and mucin were shown to inhibit H. pylori lectin-agglutination reactions. Pre-treatment of the bacterial cells with formalin and sulphuric acid did not alter the agglutination patterns with lectins. However, sodium periodate treatment of bacterial cells were shown to inhibit agglutination reaction with Con A, Lotus A and WGA lectins. On the contrary, enzymatic treatment of coccoids and spirals did not show marked inhibition of H. pylori lectin agglutination. Interes tingly, heating of H. pylori cells at 60 °C for 1 h was shown to augment the agglutination with all of the lectins tested.

CONCLUSION: The considerable differences in lectin agglutination patterns seen among the two differentiated forms of H. pylori might be attributable to the structural changes during the events of morphological transformation, resulting in exposing or masking some of the sugar residues on the cell surface. Possibility of various sugar residues on the cell wall of the coccoids may allow them to bind to different carbohydrate receptors on gastric mucus and epithelial cells. The coccoids with adherence characteristics like the spirals could aid in the pathogenic process of Helicobacter infection. This may probably lead to different clinical outcome of H. pylori associated gastroduodenal disease.

Agglutination of Helicobacter pylori coccoids by lectins.

Discrepancies among reports from different geographical regions worldwide on the association between the presence of cagA and peptic ulcer disease prompted this study on the predictive value of the cagA gene in Helicobacter pylori-associated gastroduodenal diseases in the Singapore population. H. pylori strains were obtained from 169 patients with a peptic ulcer, 83 with non-ulcer dyspepsia, and nine with gastric cancer. The presence of the cagA gene was evaluated by polymerase chain reaction (PCR). The expected 400 bp PCR product coding for the cagA gene was present in 232/261 (89%) H. pylori isolates. Of these, 151/169 (89%) strains from patients with peptic ulcer, 73/83 (88%) strains from patients with non-ulcer dyspepsia and 8/9 (89%) strains from cancer patients were positive for the cagA gene. There was no statistically significant difference between the prevalence of cagA-positive strains from patients with distinct clinical outcomes (p > 0.05). The prevalence of cagA-positive strains in the Singapore population is high regardless of clinical disease status. The results suggest that the cagA gene is not a universal virulence marker of H. pylori.

The status of the cagA gene does not predict Helicobacter pylori-associated peptic ulcer disease in Singapore.

Background.

Diversity of DNA among H. pylori strains isolated from different patients can serve as a useful marker for differentiating strains. DNA profiles of H. pylori obtained from sequential gastric biopsies were identical in most patients indicating that a given strain can persist from months to years. Patients colonized with more than two strains isolated mainly from different anatomical sites have been reported. This work examined whether the gastric antrum of patients with dyspepsia is colonized by single or multiple strains of H. pylori as well as the in vitro competition of different strains of H. pylori.



Materials and Methods.

Two antral biopsy specimens from each of the 124 patients were cultured for H. pylori. DNA fingerprinting of H. pylori isolates was performed using random amplified polymorphic DNA (RAPD) analysis. To elucidate the possible interaction among H. pylori isolates, bacterial populations of two H. pylori strains cogrown in broth medium over 21 days were enumerated and DNA fingerprinting was compared.



Results.

A total of 58 patients showed the presence of H. pylori in both antral specimens, while five patients had H. pylori in only one of the two samples. These 58 patients were shown to harbor a single strain of H. pylori as analyzed by RAPD fingerprinting. In vitro studies of bacterial interaction of two different strains of H. pylori showed growth competition resulting in the predominance of a single strain.



Conclusions.

The results support the concept that a single strain predominates in the gastric antrum site of patients studied.

Jie-Song Hua

Papers

Association of peptic ulcer with increased expression of Lewis antigens but not cagA, iceA, and vacA in Helicobacter pylori isolates in an Asian population

Is the coccoid form of Helicobacter pylori viable

Agglutination of Helicobacter pylori coccoids by lectins.

The status of the cagA gene does not predict Helicobacter pylori-associated peptic ulcer disease in Singapore.

Predominance of a single strain of Helicobacter pylori in gastric antrum.