Study on the Mechanism of Trimethoprim-Sulfamethoxazole Resistance in Stenotrophomonas Maltophilia / 现代检验医学杂志

Objective Class 1 integrase(intI 1),qacE△1-sul1 and sul2 genes were detected in trimethoprim-sulfamethoxazole resistant Stenotrophomonas maltophilia by PCR to assess the relationship between the antibiotic resistance mechanism for trimethoprim-sulfamethoxazole (TMP-SMZ)and these genes distribution.Methods S.maltophilia isolates were collected from patients treated in Affilitated hospital of Nanjing University of TCM during January to May in 2013,DNA was ab-stracted by boiling method and genes were detected by polymerase chain reaction.Results intI 1 genes were observed posi-tive in 25 of 28 strains resistant for TMP-SMZ,qacE△1-sul1 genes were positive in 21 while sul2 genes positive in 15,the positive rates of intI 1,qacE△1-sul1 and sul2 genes were 89.29%,75% and 53.57%;in 18 trimethoprim-sulfamethoxazole sensitive strains,5 were intI 1 positive,4 were qacE△1-sul1 positive while sul2 were none,the positive rates of intI1 and qacE△1-sul1 were 27.78% and 22.22%.Conclusion Most of stenotrophomonas maltophilia resisted trimethoprim-sulfa-methoxazole had intI 1,qacEΔ1-sul 1 and sul2 genes.

Mutations analysis in a pedigree with maternally inherited sensorineural hearing loss / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the mutations in a pedigree with maternally inherited sensorineural hearing loss, and to investigate whether 235delC heterozygote mutation in gap junction protein beta 2 (GJB2) gene modulates the severity of hearing loss associated with the A1555G mitochondrial mutation.</p><p><b>METHODS</b>The PCR products were digested with the Alw26 I restriction enzyme, followed by direct sequencing to detect the mitochondrial mutations in 72 members of a core pedigree of an extensive family with matrilineal nonsyndromic deafness; 235delC mutation of the GJB2 gene was screened in this family by using the Apa I restriction enzyme and direct sequencing.</p><p><b>RESULTS</b>The A1555G mutation of the mitochondrial DNA was present in all 27 members of maternal line, out of them, 21 members had phenotype of deafness (77.8%), with a high penetrance. Only three maternal line members of 72 members possessed 235delC heterozygote mutations, and the three had different phenotypes.</p><p><b>CONCLUSION</b>The A1555G homozygous mutation of mitochondrial DNA is the susceptive etiological factor of nonsyndromic deafness in this family, but in the study of this pedigree, the 235delC heterozygous mutation in GJB2 gene may not aggravate the symptoms of hearing loss associated with the A1555G mitochondrial mutation.</p>