The phenotypic and genetic characteristics of resistance to macrolides and lincosamides among 72 Ureaplasma urealyticum clinical strains isolated in Guangzhou, China were investigated in this study. Strains were studied by resistance phenotyping, detection of resistance genes (ermB, msrA, msrB, msrC, and msrD), and determining the significance of an association between the presence of resistance genes and the int-Tn gene (a genetic marker of transposon). The ermB, msrA, msrB, msrC, and msrD genes were obtained in 21, 1, 12, 0, and 24 strains, respectively. The msrB and msrD genes were detected in strains of macrolides (M) or macrolides-streptogramin B (MS) resistance phenotype, and the ermB gene was detected in strains of M or macrolide-lincosamide (ML) phenotype in U. urealyticum. Statistical analysis revealed that only the ermB gene was closely associated with the int-Tn gene. It was concluded that U. urealyticum harbored the ermB, msrA, msrB, and msrD genes which confer resistance to macrolides and (or) lincosamides. The ermB gene may be located in the U. urealyticum transposon.

CD44v, especially splice variants containing exon v6, has been shown to be related closely to development of different tumors. High levels of CD44v6/v7 have been reported to be associated with invasiveness and metastasis of many malignancies. The objective of this study was to detect expression of CD44v6-containing variants in patients with acute promyelocytic leukemia (APL) and evaluate the potential of CD44v6/v7 for risk stratification. Reverse transcription polymerase chain reaction (RT-PCR) followed by PCR product purification, ligation into T vectors and positive clone sequencing were used to detect CD44 v6-containing variant isoforms in 23 APL patients. Real-time quantitative PCR of the CD44v6/v7 gene was performed in patients with APL and in NB4 cells that were treated with all-trans retinoic acid (ATRA) or arsenic trioxide (As 2 O 3 ). Sequencing results identified four isoforms (CD44v6/v7, CD44v6/v8/v10, CD44v6/v8/v9/v10, and CD44v6/v7/v8/v9/v10) in bone marrow mononuclear cells of 23 patients with APL. The level of CD44v6/v7 in high-risk cases was significantly higher than those with low-risk. Higher levels of CD44v6/v7 were found in three patients with central nervous system relapse than in other patients inthe same risk group. Furthermore, in contrast to ATRA, only As 2 O 3 could significantly down-regulate CD44v6/v7 expression in NB4 cells. Our data suggest that CD44v6/v7 expression may be a prognostic indicator for APL.

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