Who Could Be Blamed in the Case of Discrepant Histology and Serology Results for Helicobacter pylori Detection?

BACKGROUND

Discrepancies between histology and serology results for Helicobacter pylori detection could be caused by a variety of factors, including a biopsy sampling error, expertise of the pathologist, natural loss of infection due to advanced atrophy, or a false-positive serology in the case of a previous infection, since antibodies may be present in blood following recovery from the infection.

AIMS

To identify true H. pylori-positive individuals in discrepant cases by serology and histology using real time polymerase chain reaction (RT-PCR) as a gold standard.

METHODS

Study subjects with discrepant histology and serology results were selected from the GISTAR pilot study data base in Latvia. Subjects having received previous H. pylori eradication therapy or reporting use of proton pump inhibitors, antibacterial medications, or bismuth containing drugs one month prior to upper endoscopy were excluded. We compared the discrepant cases to the corresponding results of RT-PCR performed on gastric biopsies.

RESULTS

In total, 97 individuals with discrepant results were identified: 81 subjects were serology-positive/histology-negative, while 16 were serology-negative/histology-positive. Among the serology-positive/histology-negative cases, 64/81 (79.0%) were false-positives by serology and, for the majority, inflammation was absent in all biopsies, while, in the serology-negative/histology-positive group, only 6.2% were proven false-positives by histology.

CONCLUSIONS

Among this high H. pylori prevalent, middle-aged population, the majority of discrepant cases between serology and histology were due to false positive-serology, rather than false-negative histology. This confirms the available evidence that the choice of treatment should not be based solely on the serological results, but also after excluding previous, self-reported eradication therapy.

Survey of the antimicrobial resistance of Helicobacter pylori in France in 2018 and evolution during the previous 5 years

BACKGROUND AND OBJECTIVES

Surveillance of Helicobacter pylori resistance to antibiotics was carried out in France in 2014, 2016, and 2018. We report here the results of the 2018 survey as well as the evolution over the 5-year period.

MATERIALS AND METHODS

In this observational study, gastric biopsies were obtained by 62 gastroenterologists randomly selected in 5 regions of France and sent to a central laboratory where culture, antimicrobial susceptibility testing, and a real-time PCR were performed in order to detect H pylori and its mutations associated with clarithromycin resistance.

RESULTS AND CONCLUSION

During the year 2018, 951 patients were included: 55.3% women, mean age: 52.4 years ± 15.7, 71.6% born in France. Among them, 359 patients were H pylori positive by both culture and real-time PCR, and 7 more by PCR only. There were 244 naive patients, 110 previously treated patients, and unknown for 5. Primary resistance to clarithromycin was 20.9% [16.3-26.4], to levofloxacin 17.6% [13.4-22.9], and to metronidazole 58.6% [52.3%-64.6%]. Secondary resistance for these antibiotics was 56.4%, 22.7%, and 87.3%, respectively. There was no resistance to amoxicillin and tetracycline and very low resistance to rifampicin (1.2%) in both naive and treated patients. Primary resistance to clarithromycin decreased from 22.2% to 20.3% between 2014 and 2016, and appears to be stable since then. This can be linked to a stable consumption of macrolides over the 3-year time period. Primary levofloxacin resistance was relatively stable while metronidazole resistance increased. Interestingly, in both naive and treated patients, amoxicillin and rifampicin resistance were rare.

Socio-economic inequalities in suicide attempts and suicide mortality in Québec, Canada, 1990-2005

OBJECTIVES

Little research has evaluated changes in the association between area deprivation and suicidal behaviour over time. This study investigated patterns in suicide attempts and suicide mortality according to material deprivation in the province of Québec, Canada between 1990 and 2005.

STUDY DESIGN

Ecological analysis.

METHODS

Data on suicide attempts were extracted from the hospital discharge summary database (n=47,516) and data on suicides were extracted from the Québec death file (n=20,851). Gender- and age-specific (10-24, 25-44, 45-64 and > or = 65 years) suicide attempt and mortality rates were calculated for four time periods (1990-1993, 1994-1997, 1998-2001 and 2002-2005) for the entire Québec population aged 10 years and older residing in 162 communities ranked by decile of material deprivation. Absolute and relative measures of inequality were calculated to summarize differences between the most and least materially deprived areas. Commonly used methods of suicidal behaviour were examined.

RESULTS

Differentials in suicide attempt hospitalization between the most and least deprived areas were present for all age groups, and these decreased slightly among males and increased among females over time. Inequalities in suicide attempts were greatest among young adults (age 25-44 years) for both genders, and were smallest among the elderly (> or = 65 years). For suicide mortality, differentials increased among females but not males; these differentials were greatest among males and 25-44 year olds, and smallest among the elderly. Differentials in commonly used methods were evident for poisoning hospitalizations in both genders and for hanging deaths among males.

CONCLUSIONS

In Québec, differences in suicide attempts and mortality between the most and least materially deprived areas persisted or even increased over time. Inequalities were more pronounced for suicide attempts than for suicide mortality, and were greatest among adults of working age. Strategies to reduce socio-economic differences in suicidal behaviour may be important.

Temperature sensitivity of two different steps in the viral life cycle of feline immunodeficiency virus

Feline immunodeficiency virus (FIV) multiplication is totally blocked by incubation of infected cells at 41 degrees. This inhibition does not take place with a thermoresistant strain of FIV, designated m41, indicating the role played by the viral genome in temperature sensitivity. We have investigated the steps in the life cycle of wild-type FIV that are thermosensitive and found that they depend on the host cells infected. In CrFK cells, FIV replication was inhibited after the penetration step at 41 degrees. Synthesis of viral RNA and DNA was barely detectable and no viral antigen appeared in the extracellular medium. Nevertheless, viral multiplication resumed on incubation at 37 degrees, suggesting a state of latency at the elevated temperature. In peripheral blood mononuclear cells (PBMCs), the FIV cycle was inhibited at 41 degrees after the synthesis of viral DNA. Several viral mRNAs failed to appear as fully spliced products and no viral antigen was found in the extracellular medium. As in CrFK cells, viral multiplication occurred in PBMCs after a shift to the permissive temperature. These results suggest that at least two steps in the viral life cycle are sensitive to 41 degrees and that two different viral functions of the thermoresistant mutant m41 are modified to overcome temperature sensitivity.

A thermoresistant strain of feline immunodeficiency virus (FIV) with an altered cytopathic effect and a restricted cell tropism

A thermoresistant strain, designated m41, of feline immunodeficiency virus (FIV) was selected after 31 successive passages of chronically infected IRC4 cells at 41 degrees C. The wild-type virus (wt) which served as a control was cultivated the same number of times at 37 degrees C. In Crandell feline kidney cells (CrFK), the replication of m41 was similar at 37 degrees C and 41 degrees C, whereas wt multiplied only at 37 degrees C. Furthermore, m41 was more resistant than the wt strain at temperatures ranging from 37 to 56 degrees C. Syncytia formation was observed with m41 when the CrFK were incubated at 41 degrees C whereas neither m41 nor wt produced syncytia at 37 degrees C. The level of replication of wt and m41 on feline lymphoid primary cells at 37 degrees C was similar. In contrast to wt, m41 was unable to infect bone marrow macrophages. Since one or several mutations in the envelope (env) gene could be involved in changes of cell fusion properties and of cellular tropism, the nucleotide sequence of the env gene derived from wt and m41 respectively was determined. Ten mutations were found in the env gene of m41, thus leading to 9 amino acid modifications in the envelope glycoproteins. These results suggest that structural modifications of the viral envelope proteins are prerequisites for the replication of a thermoresistant FIV strain at elevated temperature and are correlated with the newly acquired viral phenotype.