Study on gene homology of multi-drug resistant colonized bacteria and infectious bacteria in ICU patients / 国际检验医学杂志

Objective To study the gene homology of intestinal colonized and infectious bacteria in ICU patients to provide the epidemiological and molecular biological basis for formulating the control measures of multi resistant bacterial hospital infection. Methods The multi-drug resistant colonized bacteria isolated from the anal swabs and the same multi-drug resistant bacteria isola-ted from the clinical samples in the same patients were matched.The Diversilab automatic repetitive extragenic palindromic(REP)-PCR typing system was adopted to analyze the gene homology of multi-drug resistant colonized bacteria and infectious bacteria in the intestinal tract.Results 4 pairs of multi-drug resistant colonized bacteria and the same multi-drug resistant bacteria isolated from the clinical samples on admission in the same patients were selected and performed the homology detection,2 pairs had the ho-mology and 2 pairs had no homology;4 pairs of multi-drug resistant colonized bacteria and the same multi-drug resistant bacteria isolated from the clinical samples in the patients with hospital infection were performed the homology detection,4 pairs all showed the homology.Conclusion The multi-drug resistant colonized bacteria and the infectious bacteria in ICU patients have the homolo-gy.The multi-drug resistant colonized bacteria can cause the occurrence of hospital infection,so their management should be strengthened in clinic.

Two novel mutations of the retinitis pigmentosa GTPase regulator gene in two Chinese families with X-linked retinitis pigmentosa / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To detect mutations of the retinitis pigmentosa GTPase regulator (RPGR) gene in two Chinese X-linked retinitis pigmentosa families.</p><p><b>METHODS</b>Fragments of exons 1-19 of the RPGR gene were amplified with intronic primers, using genomic DNA as template. The polymerase chain reaction (PCR) products were analysed by single-strand conformation polymorphism (SSCP) and direct sequencing. Mutations were identified by comparing DNA sequences of the patients with those of the normal controls.</p><p><b>RESULTS</b>Two novel mutations, c1536delC and E332X, were identified in exons 12 and 9 of the RPGR gene in both families. Each mutation was the first mutation found in their respective exons. Both mutations were predicted to cause premature termination, which resulted in truncated proteins without normal functions of the RPGR products.</p><p><b>CONCLUSIONS</b>Both mutations are the genetic basis of the pathogenesis in the respective families. Our data might be helpful in analysing the function of the RPGR protein.</p>

Screening of Specific Probes from the DNA Library of Cryptococcus neoformans / 中华皮肤科杂志

To screen specific DNA probes by double hybridization from the constructed DNA li- brary of serotype A Cryptococcus neoformans.On the basis of the nucleotide sequence of vector pUC18, a pair of primers was synthesized.The insert fragments were amplified from the library on a PCR pro- cessor.The PCR products were spotted onto hybond-N~+ membranes.All inserts amplified from the ge- nomic library by PCR were screened by dot blot with 26 ~(32)P-labelled DNA from infectious agents for dif- ferentiation and from healthy persons.Twenty-eight candidate clones were obtained.The twenty-eight clone inserts got from low melting point agar were further characterized by dot blot with above 27 kinds of DNA for differentiation.Three specific DNA probes from the library of serotype A Cryptococcus neo- formans were obtained.Colony pCNIIA6 was serotype A-specific,which gave signals only with sertype A strain and did not cross hybridize with other DNAs.Colony pCNIIB5 was species-specific which gave signals only with DNA from Cryptococcus neoformans.Colony pCNIIIG1 was specific for var.neofor- mans,which gave signals only with serotype A and D strains.We can make a rapid diagnosis of Crypto- coccus neoformans infection at an early stage and distinguish the variants of C.neoformans and C.gattii using above specific probes.

Rapid Diagnosis of Oryptococcal Meningitis by Polymerase Chain Reaction / 中华皮肤科杂志

Polymerase chain reaction(PCR) was used for the first time in China for the diagnosis of cryptococcal meningitis by amplification of specific sequence of the rDNA genes of C.neoformans.All 11 strains of C.neoformans yielded a specific 136 bp fragment but 21 non-C,neoformans strains did not. The sensitivity of the amplification was about 10 cfu.With the aid of the rDNA-PCR,23 of the 23 cere- brospinal fluids (CSF) specimens which had been confirmed C.neoforrnans positive by smear and/or cul- ture were PCR-positive(100%),and 13 of the 14 CSF specimens which had been confirmed C.neofor- mans negative by smear and culture were PCR-negative (93%).The results of the present study suggest that rDNA-PCR is a sensitive and specific method for rapid diagnosis of cryptococcal meningitis.

FURTHER REPORT ON APPLICATION OF DNA PROBE IN DIAGNOSIS OF VIVAX MALARIA INFECTION / 中国寄生虫学与寄生虫病杂志

Southern blotting with a labeled and linearized pUC 19 DNA containing a specific fragment of 0. 24 kb DNA of Plasmodium vivax asexual blood stages (kindly offered by Dr. C. Kidson )was used for further identification of blood samples showing positive reaction by dot-blot hybridization. The results showed that those with positive reaction from patients with P. vivax, with P. falciparum or with fever but with negative microscopic findings were also positive by Southern blotting. It was confirmed that some of those positive with P. falciparum were likely to infect P. vivax at the same time. So did a part of those with fever but negative in the blood films (Figs. 1,2).