Evaluation of chemiluminescence immunoassay in the detection of treponema pallidum antibody / 国际检验医学杂志

Objective To analyze the clinical performance of chemiluminescence immunoassay (CLIA)in determination of trepo‐nema pallidum antibody(TP antibody) .Methods The results detected by enzyme‐linked immunosorbent assay( ELISA)were regar‐ded as relative standards ,and results detected by treponema pallidum particle assay (TPPA) were regarded as recognition criteria . 2 223 serum samples of outpatients and inpatients were collected ,and TP antibodies were detected by CLIA and ELISA method re‐spectively ,and followed by confirmation of TPPA test .Results Among 2 223 serum samples ,53 samples were TP antibody positive detected by ELISA and 60 samples were TP antibody positive detected by CLIA ,and the positive incidence of TP antibody detected by the ELISA and CLIA method was 2 .34% and 2 .65% respectively .The positive predictive value ,sensitivity and specificity of the CLIA method was 98 .33% ,100 .00% and 99 .95% ,repectively .Conclusion The CLIA method could be considered adequate for screening of TP antibody in a large volume of samples ,with characteristics of automatic ,quantitative and short turn around time .

Clinical performance of hepatitis B surface antigen quantification with high sensitivity chemiluminescent enzyme immunoassay technology / 中华检验医学杂志

Objective To assess the clinic application of a new-style automated immunoassay system HISCL ( high sensitivity chemiluminescent enzyme immunoassay ) with high sensitive chemiluminescence substrate CDP-Star?, bind-free separate technology and filter conversion technology.Methods The performance verification test evaluated HISCL′s specification including reproducibility, functional sensitivity, linearity, accuracy, and sensitivity for HBsAg seroconversion.To evaluate the specificity , 1 007 HBsAg-negative specimens , 82 potentially interfering specimens were from conventional specimens in West China Hospital , Sichuan University between October and December of 2014.At the same time, with these results to determine the rate of the specimens that their results are in negative grey zone.259 HBsAg-positive specimens and 27 weakly-positive specimens were tested for the comparison between the HISCL and ECLIA ( electrochemiluminescence immunoassay ) HBsAg quantification.A linear regression model , Pearson′s correlation and Bland-Altman analysis were used as statistical methods.Results The between day and within-lot variable coefficient of two level samples are 1.55%, 2.02%, 0.34%, 1.34%separately.The functional sensitivity of the HISCL HBsAg assay reaches 0.007 IU /ml.There is a good linearity (y=3.262x+0.082,r=0.994; y=2 303.608x-33.006,r=0.999) within range of 0-2 300 IU/ml.HISCL obtain the accurate results for the CAP control material , the agreement rate is 100%.The sensitivity for the detection of HBsAg seroconversion is high.The specificity is 99.91%.The negative grey zone rate is 1.66%.The results of these two methods have good correlation and uniformity , r=0.995, LOA:-0.3 -0.19 log10 IU/ml.Conclusions HISCL HBsAg detection system shows good detection performance.Be of the function of both qualitative and quantitative detection.And the negative “grey zone”specimen rate is low.It is wholly capable of wide linearity and quick assays for quantifying serum HBsAg levels.HISCL could contribute to improve HBsAg quantitative detection process for clinical laboratory.

Analysis of the carbapenemase-producing mechanism of Enterobacteriaceae with decreased susceptibility to carbapenems / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the distribution of Enterobacteriaceae isolated from West China Hospital, investigate the antibiotic resistance profile of Enterobacteriaceae with decreased susceptibility to carbapenems and explore the molecular mechanism.</p><p><b>METHODS</b>Forty-five Enterobacteriaceae strains resistant or with reduced susceptibility to carbapenems were isolated from patients in West China Hospital. The antimicrobial susceptibility and carbapenemase-producing phenotypes of the bacteria were examined and specific PCR were performed to determine the molecular mechanism.</p><p><b>RESULTS</b>Of the 45 isolates, 17, 21 and 36 were resistant or intermediate strains to imipenem, meropenem and ertapenem, respectively. The majority of these isolates showed resistance to cephalosporins. The modified Hodge test resulted in the highest positivity rate (77.8%), followed by EDTA disc test (57.8%) and PBA disc test (22.2%). BlaTEM, blaSHV and blaCTX-M were detected in 60.0%, 53.3% and 15.6% of these strains with reduced susceptibility. The rate of strains carrying 2 or more genes was 44.4%, and the detection rate of blaIMP was 48.9%. BlaKPC was identified in 4 (8.9%) high-level resistant strains and confirmed to locate on the plasmid.</p><p><b>CONCLUSION</b>Production of carbapenemase contributes to reduced susceptibility of carbapenems in Enterobacteriaceae. The presence of blaKPC, MBL and ESBL, and their possible combinations can be the main factor contributing to carbapenem resistance or reduced susceptibility in Enterobacteriaceae. The KPC-2 carbapenemase gene located on the plasmids we found in this study can cause potential horizontal transmission across strains.</p>

Identification and distribution of the clinical isolates of imipenem-resistant Pseudomonas aeruginosa carrying metallo-beta-lactamase and/or class 1 integron genes / 华中科技大学学报（医学）（英德文版）

To investigate the distribution of the genes of two major metallo-beta-lactamases (MBL; i.e., IMP and VIM) and class 1 integrons (intI) in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for bla ( IMP-1 ), bla ( VIM ) and bla ( VIM-2 ) genes. The MBL-positive isolates were further assessed for class 1 integrons by PCR using specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the bla ( VIM ) gene was found in 81.5% (53/65) of all isolates, bla ( VIM-2 ) gene was found in only 1 isolate and the intI gene was observed in 45.3% (24/53) of bla ( VIM )-positive isolates. One isolate carried simultaneously both bla ( IMP-1 ) and intI genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM beta-lactamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P. aeruginosa.

The drug-resistant mechanism of clinical non-fermenting bacilli producing IMP-1 metalloenzyme / 生物医学工程学杂志

A total of 50 clinical imipenem-resistant isolates of Pseudomonas aeruginosa and Acinetobacter baumannii were subjected to the ceftazidime-2- mercaptoethanol -double-disk synergy test and to the PCR assays with primers specific for bla(IMP-1). After the process of sequencing the positive one to identify the results, PCR analysis was conducted with primers specific for class 1 integrons. For synergy test, 28 isolates gave positive results, among which were 27 Pseudomonas aeruginosa and Acinetobacter baumannii. Only one Pseudomonas aeruginosa was found to carry bla(IMP-1), and bla(Int1) at the same time. This is the first ascertainment of IMP-1 producing Pseudomonas aeruginosa isolate carrying bla(IntI1) in West China, which is of significance to the research on the clinical spread of these drug-resisitant genes.