John Holton

AMOXYCILLIN PLUS TINIDAZOLE FOR CAMPYLOBACTER PYLORI GASTRITIS IN CHILDREN: ASSESSMENT BY SERUM IgG ANTIBODY, PEPSINOGEN I, AND GASTRIN LEVELS

32 children (mean age 12 years, range 6-18) with non-specific abdominal pain and Campylobacter pylori positive gastritis received a six week course of daily oral amoxycillin (50 mg/kg) and tinidazole (20 mg/kg). Before treatment and one month after stopping treatment, endoscopic biopsy samples were taken from the antral mucosa and serum C pylori IgG antibody, pepsinogen I, and gastrin levels were measured in fasting blood samples. One month after treatment 30 children (94%) were cleared of C pylori and gastritis had resolved in 27 (84%) and was improved in the remaining 5. Serum IgG, pepsinogen I, and gastrin levels were significantly decreased after treatment. Of 12 children assessed at six months, 9 remained free of C pylori. Increases or decreases in IgG level indicated clearance or recurrence, respectively, of C pylori.

Human domain antibodies against virulence traits of Candida albicans inhibit fungus adherence to vaginal epithelium and protect against experimental vaginal candidiasis.

Antibody variable domains (domain antibodies [DAbs]) are genetically engineered antibody fragments that include individual heavy-chain (VH) or kappa-chain (Vkappa) variable domains and lack the Fc region. Human DAbs against the 65-kDa mannoprotein (MP65) or the secretory aspartyl proteinase (SAP)-2 of Candida albicans (monospecific DAbs) or against both fungal antigens (heterodimeric, bispecific DAbs) were generated from phage expression libraries. Both monospecific and bispecific DAbs inhibited fungus adherence to the epithelial cells of rat vagina and accelerated the clearance of vaginal infection with the fungus. When heterodimeric DAbs were used, the clearance of infection was at least equivalent to treatment with fluconazole. The in vivo protective effects of DAbs were demonstrated by both pre- and postchallenge schedules of DAb administration and with both fluconazole-susceptible and fluconazole-resistant strains of C. albicans. This is the first demonstration that human DAbs lacking the Fc constituent can efficiently control an infection and can act largely by inhibiting adherence.

Prevalence of peptic ulcer in Helicobacter pylori positive blood donors.

This study aimed to determine the importance of raised antibodies to Helicobacter pylori in an asymptomatic population. A total of 128 asymptomatic blood donors who were seropositive for H pylori and consented to endoscopy were investigated. These subjects were from a population of 1010 blood donors screened for antibodies to H pylori. A questionnaire was completed to determine if any subjects had complained of symptoms, and they subsequently had endoscopy. Altogether 121 of 128 were positive for H pylori by histology and urease test and/or culture and all 121 had chronic active gastritis on histology. Twenty five of these subjects had peptic ulcer (20 duodenal, five gastric), a further 21 had erosive duodenitis, and two were found to have gastric cancer. H pylori associated peptic ulcer disease and duodenitis occur more frequently than previously recognised and this suggests that H pylori infection, even if asymptomatic, is of far greater clinical relevance than originally thought.

PCR primers that can detect low levels of Mycobacterium leprae DNA

There are several specific PCR-based methods to detect Mycobacterium leprae DNA, but the amplicons are quite large. For example, primers that target the 36-kDa antigen gene and are in common diagnostic use yield a 530-bp product. This may be a disadvantage when examining samples in which the DNA is likely to be damaged and fragmented. Therefore, two sets of M. leprae-specific nested primers were designed, based on existing primer pairs which have been shown to be specific for M. leprae. Primers that targeted the 18-kDa antigen gene gave an outer product of 136 bp and inner product of 110 bp. The primers based on the RLEP repetitive sequence yielded a 129-bp outer product and 99-bp nested product. With dilutions of a standard M. leprae killed whole-cell preparation as the source of DNA, both single-stage and nested PCR were performed after optimisation of the experimental conditions. Compared with the 36-kDa antigen gene primers, the 18-kDa antigen gene outer primers were 100-fold more sensitive and the RLEP outer primers were 1000-fold more sensitive. As an illustration of two possible applications of these new primers, positive results were obtained from three skin slit samples from treated lepromatous leprosy patients and three archaeological samples from human remains showing typical leprosy palaeopathology. It was concluded that these new primers are a useful means of detecting M. leprae DNA which is damaged or present at a very low level.

Are Helicobacter species and enterotoxigenic Bacteroides fragilis involved in inflammatory bowel disease

The aim of this study was to determine if either Helicobacter or enterotoxigenic Bacteroides fragilis (ETBF) was linked to inflammatory bowel disease (IBD), using PCR. We analyzed the luminal washings and colonic biopsies of 35 patients with IBD and 37 control patients. The presence of Helicobacter was confirmed in the luminal washing of one IBD patient and three control patients and in the biopsies of two IBD patients. Ten of 28 control patients and 8 of 32 IBD patients had a positive luminal washing for the enterotoxin gene. Six of 33 control patients and 4 of 32 IBD patients had positive biopsies. The prevalence of the enterotoxin gene was higher in IBD patients with active disease compared with patients with inactive disease, although it did not achieve statistical significance. In conclusion, Helicobacter was not associated with IBD in our population of patients, although ETBF may be associated with active disease.

CAMPYLOBACTER PYLORI IN ABATTOIR WORKERS: IS IT A ZOONOSIS?

Sera from 98 abattoir workers were tested for IgG to Campylobacter pylori, C jejuni, and klebsiella. Clerical workers had significantly lower C pylori and C jejuni IgG titres than any of the groups in direct contact with freshly cut animal parts. No difference was found for antibodies to klebsiella. 28 non-clerical workers with high-titre C pylori IgG consented to upper gastrointestinal endoscopy. C pylori associated gastritis was found in all 28, and four weeks of colloidal bismuth subcitrate (240 mg twice daily) was prescribed. On repeat testing at three months all showed a decrease in IgG titres to C pylori but not to C jejuni, whereas 18 untreated non-endoscoped workers showed no change. These findings raise the possibility that C pylori infection is a zoonosis.

Helicobacter pylori in children with peptic ulcer and their families

Little is known about the source and spread ofHelicobacter pylori, but transmission from infected family contacts has been suggested. We have therefore investigated 15 children with peptic ulcer and their first-degree relatives forH. pylori. Serum anti-H. pylori IgG, pepsinogen I, and gastrin levels were measured. Endoscopy was carried out on the children and relatives, and biopsies were taken from the gastric antrum for histology, microbiology, and urease testing. Six of 11 children with duodenal ulcer (55%) and two of four children with gastric ulcer (50%) were positive forH. pylori. Fourteen of 16 parents (87%) and eight of 13 siblings (61%) ofH. pylori-positive children with peptic ulcer were also infected compared with eight of 14 parents (57%) and none of four siblings ofH. pylori-negative children with peptic ulcer (P< 0.10, >0.05, and NS, respectively). The children withH. pylori-negative peptic ulcer and negative siblings combined were younger than positive children with peptic ulcer and positive siblings (P<0.001). The reliability of serum anti-H. pylori IgG level as a screening test for infection was confirmed. These findings call into question a pathogenetic role forH. pylori in some childhood peptic ulceration, but do suggest that person-to-person spread of infection occurs.

Eighteen month follow up of Helicobacter pylori positive children treated with amoxycillin and tinidazole.

Sixty three children with dyspepsia (mean age 12 years, range one to 18, M/F 41/22) were Helicobacter pylori positive by histology of gastric antral biopsy specimens and were treated with a six week course of amoxycillin (50 mg/kg) and tinidazole (20 mg/kg). The endoscopic diagnoses were: normal (16), nodular gastritis (19), oesophagitis (four), duodenal ulcer (13), and gastric ulcer (11). H pylori was eradicated in 54 (87%) and histological gastritis resolved in 51 and was improved in the other three. Repeat investigation was offered at six monthly intervals. Reinfection was found in three of 34 (9%) at six months, in none of 22 at 12 months, and in two of 18 (11%) at 18 months, yielding an 18 month cumulative relapse rate of 20%. Children with persisting infection despite treatment remained positive during follow up. Serum H pylori IgG concentrations fell after treatment (p < 0.001), and for individual children during follow up there was a progressive decline, but an increased concentration indicated recurrence. After eradication of H pylori by combined amoxycillin and tinidazole treatment, only a minority of children relapse during the ensuing 18 months.

Serum pepsinogen I and IgG antibody to Campylobacter pylori in non-specific abdominal pain in childhood.

A consecutive series of 51 children (mean age 11 years) who presented with recurrent abdominal pain were investigated by upper gastrointestinal endoscopy including three antral biopsies for microscopy, culture and urease testing. Serum IgG, IgA, and IgM antibodies to Campylobacter pylori (C pylori) were measured by the ELISA technique. Serum pepsinogen I was also measured. Thirty two children showed histological evidence of gastritis. All had C pylori on microscopy and or culture. Nineteen children showed no histological gastritis nor evidence of C pylori on microscopy, culture and/or urease testing. The IgG and IgA antibody levels to C pylori were significantly higher in C pylori positive children than in the negative group (p less than 0.001). Serum pepsinogen I concentrations were also significantly higher in C pylori positive children than in negative (p less than 0.001). Measurement of IgG antibody levels, combined with serum pepsinogen I estimation, predict the presence of C pylori associated gastritis in children with a sensitivity and specificity of up to 95%. It may be used therefore to predict gastritis and even peptic ulceration in children presenting with non-specific upper abdominal pain.

Invasive and non-invasive tests for Helicobacter pylori infection

There are two general ways in which a diagnosis of infection by Helicobacter pylori can be made: by using either an invasive or non‐invasive procedure. The invasive procedures involve an endoscopy and biopsy. A biopsy is essential because often the mucosa may appear macroscopically normal but nevertheless be inflamed. A biopsy is obtained by histological examination, culture, polymerase chain reaction or detection of the presence of urease activity in biopsy material.