Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance.

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

Serum Helicobacter pylori antibody reactivity in seven Asian countries using an automated latex aggregation turbidity assay.

BACKGROUND AND AIM: To determine the application range of diagnostic kits utilizing anti-Helicobacter pylori antibody, we tested a newly developed latex aggregation turbidity assay (latex) and a conventional enzyme-linked immunosorbent assay (E-plate), both containing Japanese H. pylori protein lysates as antigens, using sera from seven Asian countries. METHODS: Serum samples (1797) were obtained, and standard H. pylori infection status and atrophy status were determined by culture and histology (immunohistochemistry) using gastric biopsy samples from the same individuals. The two tests (enzyme-linked immunosorbent assay and latex) were applied, and receiver operating characteristics analysis was performed. RESULTS: Area under the curve (AUC) from the receiver operating characteristic of E-plate and latex curves were almost the same and the highest in Vietnam. The latex AUC was slightly lower than the E-plate AUC in other countries, and the difference became statistically significant in Myanmar and then Bangladesh as the lowest. To consider past infection cases, atrophy was additionally evaluated. Most of the AUCs decreased using this atrophy-evaluated status; however, the difference between the two kits was not significant in each country, but the latex AUC was better using all samples. Practical cut-off values were 3.0 U/mL in the E-test and 3.5 U/mL in the latex test, to avoid missing gastric cancer patients to the greatest extent possible. CONCLUSIONS: The kits were applicable in all countries, but new kits using regional H. pylori strains are recommended for Myanmar and Bangladesh. Use of a cut-off value lower than the best cut-off value is essential for screening gastric cancer patients.

Intestinal Carriage of Extended-Spectrum ß-Lactamase- (ESBL-) Possessing Escherichia coli and Klebsiella Species among Nepalese Health Science and Non-Health Science Students.

Infections due to extended-spectrum ß-lactamase- (ESBL-) producing Gram-negative bacteria have led to increased mortality, morbidity, and economic burden worldwide. These bacteria can colonize the healthy intestine of human beings and can disseminate in communities and hospital. This study aimed to investigate the prevalence of fecal carriage of ESBL-producing Escherichia coli and Klebsiella species among health science (HS) and non-health science (NHS) students. This descriptive cross-sectional study was conducted on 104 HS and 104 NHS students in which one stool sample from each student was collected and processed for bacterial culture and sensitivity testing according to standard bacteriological procedures. Each morphotype was identified and characterized phenotypically. The antimicrobial sensitivity profile of bacterial isolates was determined by the Kirby-Bauer disk diffusion technique. ESBL production was tested by combination disk method as recommended by the Clinical and Laboratory Standards Institute. Out of 208 stool samples, E. coli and Klebsiella spp. were recovered from 203 (86.8%) and 31 (13.2%) stool samples, respectively. Among those 234 isolates, 69 were positive for ESBL which included E. coli (n = 66, 95.7%) and Klebsiella spp. (n = 3, 4.3%). Fifty (42.4%) out of 118 isolates from HS students and 19 (16.4%) out of 116 from NHS students were colonized by ESBL-producers. Compared to non-ESBL producers, a higher number of ESBL-producing isolates were resistant to ciprofloxacin (14.5% vs. 1.8%, p < 0.001), cotrimoxazole (59.4% vs. 16.4%, p < 0.001), and amikacin (10.1% vs 4.2%, p < 0.001). All E. coli and Klebsiella species isolates were susceptible to meropenem. The prevalence of fecal carriage of ESBL-producing bacteria was higher in HS students; however, there was a considerable number of these strains colonizing NHS students as well. This "iceberg phenomenon" of asymptomatic carriage of ESBL-producing pathogens might act as a source of infection in both the community and hospitals. Therefore, surveillance of carriage of drug-resistant bacteria should be performed regularly.

Helicobacter pylori Virulence Factor Cytotoxin-Associated Gene A (CagA)-Mediated Gastric Pathogenicity.

Helicobacter pylori causes persistent infection in the gastric epithelium of more than half of the world's population, leading to the development of severe complications such as peptic ulcer diseases, gastric cancer, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Several virulence factors, including cytotoxin-associated gene A (CagA), which is translocated into the gastric epithelium via the type 4 secretory system (T4SS), have been indicated to play a vital role in disease development. Although infection with strains harboring the East Asian type of CagA possessing the EPIYA-A, -B, and -D sequences has been found to potentiate cell proliferation and disease pathogenicity, the exact mechanism of CagA involvement in disease severity still remains to be elucidated. Therefore, we discuss the possible role of CagA in gastric pathogenicity.

Diffuse Gastric Cancer: A Summary of Analogous Contributing Factors for Its Molecular Pathogenicity.

Gastric cancer is the third leading cause of cancer-related deaths and ranks as the fifth most common cancer worldwide. Incidence and mortality differ depending on the geographical region and gastric cancer ranks first in East Asian countries. Although genetic factors, gastric environment, and Helicobacter pylori infection have been associated with the pathogenicity and development of intestinal-type gastric cancer that follows the Correa's cascade, the pathogenicity of diffuse-type gastric cancer remains mostly unknown and undefined. However, genetic abnormalities in the cell adherence factors, such as E-cadherin and cellular activities that cause impaired cell integrity and physiology, have been documented as contributing factors. In recent years, H. pylori infection has been also associated with the development of diffuse-type gastric cancer. Therefore, in this report, we discuss the host factors as well as the bacterial factors that have been reported as associated factors contributing to the development of diffuse-type gastric cancer.

Survival of Helicobacter pylori in gastric acidic territory.

BACKGROUND: Helicobacter pylori is well adapted to colonize the epithelial surface of the human gastric mucosa and can cause persistent infections. In order to infect the gastric mucosa, it has to survive in the gastric acidic pH. This organism has well developed mechanisms to neutralize the effects of acidic pH. OBJECTIVE: This review article was designed to summarize the various functional and molecular aspects by which the bacterium can combat and survive the gastric acidic pH in order to establish the persistent infections. METHODS: We used the keywords (acid acclimation, gastric acidic environment, H. pylori and survival) in combination or alone for pubmed search of recent scientific literatures. One hundred and forty one papers published between 1989 and 2016 were sorted out. The articles published with only abstracts, other than in English language, case reports and reviews were excluded. RESULTS: Many literatures describing the role of several factors in acid survival were found. Recently, the role of several other factors has been claimed to participate in acid survival. CONCLUSION: In conclusion, this organism has well characterized mechanisms for acid survival.

Bacterial meningitis in children under 15 years of age in Nepal.

BACKGROUND: Bacterial meningitis in children is a life-threatening problem resulting in severe morbidity and mortality. For the prompt initiation of antibacterial therapy, rapid and reliable diagnostic methods are of utmost importance. Therefore, this study was designed to find out the rate of bacterial pathogens of meningitis from suspected cases by performing conventional methods and latex agglutination. METHODS: A descriptive type of study was carried out from May 2012 to April 2013. Cerebrospinal fluid (CSF) specimens from 252 suspected cases of meningitis were subjected for Gram staining, bacterial culture and latex agglutination test. The identification of growth of bacteria was done following standard microbiological methods recommended by American Society for Microbiology. Antibiotic sensitivity testing was done by modified Kirby-Bauer disk diffusion method. RESULTS: From the total 252 suspected cases, 7.2 % bacterial meningitis was revealed by Gram staining and culture methods whereas latex agglutination method detected 5.6 %. Gram-negative organisms contributed the majority of the cases (72.2 %) with Haemophilus influenzae as the leading pathogen for meningitis. Overall, 33.3 % mortality rate was found. CONCLUSIONS: In conclusion, a significant rate of bacterial meningitis was found in this study prompting concern for national wide surveillance.

Threat of drug resistant Staphylococcus aureus to health in Nepal.

BACKGROUND: Staphylococcus aureus is the most commonly isolated organism from the different clinical samples in hospital. The emergence and dissemination of methicillin resistant Staphylococcus aureus (MRSA) and growing resistance to non-beta-lactam antibiotics is making treatment of infections due to this organism increasingly difficult. METHODS: This study was conducted to determine the frequency of Staphylococcus aureus isolated from different clinical samples, rates of MRSA and full antibiotic susceptibility profiles. Clinical samples were cultured and Staphylococcus aureus was identified using standard microbiological methods recommended by the American Society for Microbiology (ASM). Methicillin resistance was confirmed using cefoxitin and oxacillin disks. Inducible clindamycin resistance was identified using D-zone test. RESULTS: From the processed samples, 306 isolates of Staphylococcus aureus were recovered. All the isolates were susceptible to vancomycin and teicoplanin. Methicillin resistance was observed in 43.1% of isolates while inducible clindamycin resistance in 12.4% of the isolates. CONCLUSIONS: The results of our study reveals that rates of resistance to commonly prescribed antibiotics in Staphylococcus aureus clinical isolates is high. In particular, rate of methicillin resistance is alarming, prompting concern on the rational use of antibiotics and vigilant laboratory-based surveillance of resistance rates in Nepal.

Spectrum of COVID-19 induced liver injury: A review report.

The coronavirus disease 2019 (COVID-19) pandemic has caused changes in the global health system, causing significant setbacks in healthcare systems worldwide. This pandemic has also shown resilience, flexibility, and creativity in reacting to the tragedy. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection targets most of the respiratory tract, resulting in a severe sickness called acute respiratory distress syndrome that may be fatal in some individuals. Although the lung is the primary organ targeted by COVID-19 viruses, the clinical aspect of the disease is varied and ranges from asymptomatic to respiratory failure. However, due to an unorganized immune response and several affected mechanisms, the liver may also experience liver cell injury, ischemic liver dysfunction, and drug-induced liver injury, which can result in respiratory failure because of the immune system's disordered response and other compromised processes that can end in multisystem organ failure. Patients with liver cirrhosis or those who have impaired immune systems may be more likely than other groups to experience worse results from the SARS-CoV-2 infection. We thus intend to examine the pathogenesis, current therapy, and consequences of liver damage concerning COVID-19.

Susceptibility patterns and virulence genotypes of Helicobacter pylori affecting eradication therapy outcomes among Egyptian patients with gastroduodenal diseases.

BACKGROUND: Helicobacter pylori (H. pylori) is a significant human pathogen that is responsible for a variety of illnesses, including mucosa-associated lymphoid tissue lymphoma, gastric cancer, peptic ulcers, and gastritis. AIM: To investigate the frequency of H. pylori infection and its resistance patterns among Egyptian patients and to determine the influence of H. pylori virulence genetic determinants on the eradication success of 14-d triple therapy regimen. METHODS: H. pylori infections were investigated in 72 patients with gastroduodenal complications suggestive of H. pylori infection. The cagA and vacA genotypes of cultured strains were studied using polymerase chain reaction. The patients underwent 14 d of triple-therapy treatment. The treatment response was examined using histology and a rapid urease test 6 wk after therapy discontinuation. RESULTS: The intention-to-treat eradication rate was 59.2% (95%CI: 48.2%-70.3%). Rates of H. pylori resistance to clarithromycin, amoxicillin, and metronidazole were 52.8%, 81.9%, and 100%, respectively. Successful eradication of H. pylori was more significantly associated with vacA s1-positive strains [adjusted odds ratio (aOR) = 0.507, 95%CI: 0.175-0.822]. A significant association was found between failed eradication rate and H. pylori strains resistant to clarithromycin (aOR = 0.204, 95%CI: -0.005 to 0.412) and amoxicillin (aOR = 0.223, 95%CI: 0.026-0.537). CONCLUSION: This study's low H. pylori eradication rate following 14-d triple therapy is concerning and worrying. H. pylori pan-resistance to metronidazole followed by the high resistance to ciprofloxacin, amoxicillin, and clarithromycin in this research is challenging and of great concern.