Seroprevalence and pathological studies of Salmonella infection in commercial white layer birds.

The present study was conducted to determine the seroprevalence and pathology of Salmonella infection in white commercial layer birds of District Faisalabad during June 2018 and June 2020. The current study aimed to determine the isolation, identification of Salmonella gallinarum (S. gallinarum), its cultural prevalence, antimicrobial resistance, molecular characterization, and pathological lesions produced in different organs of commercial layer birds. Initial screening of poultry flocks was done through serum plate agglutination test followed by culturing in different media, motility test, molecular confirmation, and histopathology. Based on the serum plate agglutination test, seroprevalence in the commercial white layer in dead and live flocks was 40.09%. The cultural prevalence of Salmonella in the seropositive group was 75.36% and in the seronegative was 31.84%. Cultural prevalence in the liver of dead birds was 62.06%, in spleen 58.62%, and in cloacal swabs was 67.24%. A total of 178 isolates were characterized through cultural characteristic and motility tests, among them 63.48% isolates were S. gallinarum, and 36.51% isolates were S. pullorum. The antibiogram study revealed that all the tested isolates were resistant to amoxicillin, gentamycin, kanamycin, doxycyclin, and tetracyclin. While tested isolates were sensitive to ciprofloxacin against S. gallinarum. Pathologically liver was friable, showing bonze discoloration with focal necrosis, enteritis of various grades, mottled white spleen, and enlarged kidneys were found. Microscopically, leukocytic infiltration with focal necrosis and degeneration, in mucosa and submucosa of intestinal inflammatory cells were observed. In conclusion, the seroprevalence, antibiogram, and molecular characterization of Salmonella help to control the disease in a better way through bacterin production of local isolates.

Performance verification of four nucleic acid detection systems: A comparitve study / 中国输血杂志

【Objective】 To compare the analytical performance of Tigris, Panther, ChiTaS BSS1200 and cobas S201 system to see if they satisfy the requirements of blood screening and to know the concordance of the results presented by these four systems. 【Methods】 According to the relevant documents of ISO15189 and Standard Operating Procedure of Blood Station(2019), the parameters needed to be verified for nucleic acid tests(NAT) included: analytical sensitivity verification, system compare test, anti-jamming capability and anti-cross-contamination ability. 【Results】 The 95% detection limits of Tigris, Panther, ChiTaS BSS1200 and Cobas S201 for HBV-DNA(IU/mL), HIV-RNA(IU/mL) and HCV-RNA(IU/mL) were 2.013 vs 4 vs 2.995 vs 0.99, 13.039 vs 10.21 vs 30.952 vs 32.24, and 2.278 vs 2.077 vs 12.008 vs 3.39, respectively. In the performance comparison verification between NAT systems, the results of the two sets of Tigris systems were in full accordance with serum plate, with a concordance rate of 100%, Kappa value of 1, and none cross-contamination.The concordance rate of No.1 Panther system was 100%, and No.2 98%, with Kappa value of 0.961 and none cross-contamination. Hemolytic samples (5g/L Hb concentration) and lipemic blood samples (13.81 mmol/L TG concentration) had no significant effect on the detection of low-concentration samples. 【Conclusion】 No significant differences in the performance of NAT systems were notable by devices, as the four systems were fully automated with high sensitivity, which can fully satisfy the blood screening requirements. Panther system demonstrates superior analysis sensitivity in HCV-RNA/HIV-RNA and lower in HBV DNA, but also in required criteria, as compared to Tigris system. Neither hemolysis nor lipemic blood had any significant effect on the test results.