Background: High-density lipoprotein (HDL) is a major plasma lipoprotein directly associated with cholesterol metabolism. The ATP binding cassette transporter 1 gene (ABCA1) is one of the major genes modulating plasma levels of HDL-cholesterol (HDL-C). Rare alleles of ABCA1 associated with extreme HDL-C concentrations have not been previously investigated in the Chinese. Methods: Blood samples were collected from 470 subjects whose HDL-C concentrations were within the top 5% of the distribution, 335 subjects in the lowest 5%, and 220 within the range 5%-95%. First, we sequenced all exons of the ABCA1 gene from 50 sub-

The b-lactamase genes, which confer multi-drug resistance, are spreading among clinical bacterial isolates. As part of a routine surveillance program, we collected 302 bacilli isolates between June 2005 and October 2006 from four hospitals in Guangzhou, China. The isolates were screened for multidrug resistance and for the presence of b-lactamases. In all, 80 isolates were identified as multidrug-resistant with the K-B method. These isolates were phenotypically screened for b-lactamase activity by disk diffusion prescreening, diffusion confirmation, the cefoxitin three-dimensional test and the metallo-b-lactamase (MBL) synergy test. Bacteria were genotypically screened for b-lactamase genes by PCR and DNA sequencing. Among the 80 strains, drug resistance was lowest to amikacin (18.75%) and highest to ampicillin (97.50%), 26.49% had a b-lactamase phenotype, 16.56% had the extended-spectrum b-lactamase (ESBL) phenotype, 24.83% had a b-lactamase genotype, 51 carried integrons, 30 carried class I integrons and 18.75% had the ISEcp1B insertion sequence. Sequencing also detected a new CTX-M ESBL gene subtype, which had an ISEcp1B element upstream of bla CTX -M-Like , and an IS903 element downstream, forming a composite transposon. Multidrug resistance and b-lactamases continue to be prevalent in Guangzhou. Our results suggest that resistance genes are evolving and being horizontally transmitted between species.