Salmonella typhi and gallbladder cancer:report from an endemic region

BACKGROUND:Evidence exists of a link between chronic infection by Salmonella typhi(S.typhi) and the development of gallbladder cancer(GBC),but several studies from endemic regions contradict its role in the etiopathogenesis of GBC.This study used various tools to assess the prevalence of S.typhi in patients with GBC and gallstone disease(GSD) in this region with a high incidence of GBC.METHODS:S.typhi was detected in tissue and bile by PCR and culture and in serum by the Widal test and indirect hemagglutination assay(IHA).PCR with two pairs of S.typhi specific primers(flagellin gene H1d and SOP E gene) could detect 0.6 ng of S.typhi DNA.Fifty-four patients with GBC(cases) were matched with 54 patients with GSD(controls).RESULTS:Of the 54 cases,24(44.44%) were positive on the Widal test and 12(22.22%) on IHA,compared to 13(24.07%) and 5(9.26%) respectively in the controls.Eighteen(33.33%) cases showed a positive result on PCR(tissue) and 2 on PCR(bile) vs.none in the controls.Bile culture revealed no Salmonella colonies in either cases or controls.Only 3 cases were positive for Salmonella on tissue culture compared to none in the controls.The sensitivity of PCR(tissue) relative to the Widal test,IHA,culture(bile and tissue) and PCR(bile) was 100% vs.66.67%,11.11%,and 11.11%,and the specificity was 83.33% vs.100%,100%,and 100%,respectively.CONCLUSIONS:S.typhi is significantly associated with GBC compared to GSD(33% vs.0%).PCR appears to be the most specific diagnostic tool,the gold standard for S.typhi in tissue samples.

Evaluation of Usefulness of Three Serological Tests Using Native Crude Antigen in Diagnosis of Hepatic Cystic Echinococcosis Patients

Objective: To evaluate three different serological tests [Indirect Hemaglutination (IHA), Enzyme Linked Immunosorbent Assay (ELISA) and Western Blotting (WB)] using native crude antigen for diagnosis of hepatic cystic echinococcosis (HCE) patients. Materials and Methods: Sheep hydatid fluid (HF) was collected from fertile cysts obtained from a slaughterhouse and used as an antigen. Forty patients who were attended the Dr. Ersin Arslan Training and Research Hospital in Gaziantep, Turkey, were investigated. Serum samples were obtained from surgically confirmed CE patients. Healthy Turkish people and 16 patients with other helminthic infections were included as a control group. Results: Of the 40 analyzed patients, 10 (25%) were men and 30 (75%) were female. The average age was 46.97 years (s.d.;18.95). The majority of the patients had a single cystic lesion situated in one lobe of the liver (usually in the right lobe) (55%), 32.5% of patients had two cystic lesions and 12.5% of patients had multiple cyst formations with various numbers. In all cases, ultrasound (US) examinations were positive and the size of cysts was between 2.1 - 12.7 cm. Twenty-three patients of the total 40 patients were classified according to the WHO classification system based on US findings. According to the results of WB analysis, molecular weights of 8 kDa (80%), 12 kDa (80%), 22 - 24 kDa (97.5%), 26 kDa (97.5%), 34 kDa (100%), 36 - 38 kDa (90%), 45 - 50 - 55 kDa (97.5%), and 60 - 75 kDa (97.5%) bands were identified. But 34, 50, and 55 kDa bands were also found in other helminthic diseases. Conclusion: The specificity and sensitivity of three serological tests (IHA, ELISA and WB) using crude antigen were compared by diagnosing hepatic cystic echinococcosis patients. IHA and ELISA showed high sensitivity but low specificity. Western blotting showed low sensitivity but high specificity.

Accelerated Evolution of H7N9 Subtype Influenza Virus under Vaccination Pressure

No avian H7 N9 outbreaks have occurred since the introduction of H7 N9 inactivated vaccine in the fall of 2017.However,H7 N9 is still prevalent in poultry.To surveil the prevalence,genetic characteristics,and antigenic changes of H7 N9,over7000 oropharyngeal and cloaca swab specimens were collected from live poultry markets and farms in 15 provinces of China from 2017 to 2019.A total of 85 influenza virus subtype H7 N9 strains were isolated and 20 representative strains were selected for genetic analysis and antigenicity evaluation.Results indicated the decreased prevalence of low-pathogenic H7 N9 strains while highly-pathogenic H7 N9 strains became dominated since the introduction of vaccine.Phylogenetic analysis showed that strains from 2019 formed an independent small branch and were genetically distant to strains isolated in 2013–2018.Analysis of key amino acid sites showed that the virus strains may adapt to the host environment evolutionally through mutation.Our analysis predicted additional potential glycosylation sites for HA and NA genes in the 2019 strains.Sequence analysis of HA gene in strains isolated from 2018 to 2019 showed that there were an increased nucleotide substitution rate and an increased mutation rate in the first and second nucleotides of coding codons within the open reading frame.The hemagglutination inhibition(HI)assay showed that H7-Re1 and H7-Re2 exhibited a lower HI titer for isolates from 2019,while H7-Re3 and r LN79 showed a high HI titer.The protective effect of the vaccine decreased after15 months of use.Overall,under vaccination pressure,the evolution of influenza virus subtype H7 N9 has accelerated.