1.Isolation and identification of Malassezia furfur from lower respiratory tract secretions
Chinese Journal of Laboratory Medicine 2012;35(8):711-715
Objectives To culture and isolate Malassezia furfur which were suspected in sputum smears,and then to identify the isolates systematically.Methods From March 2010 to September 2011,133 lower respiratory tract secretion samples were collected in Beijing Hospital of the Ministry of Health which were suspected containing Malassezia furfur by Parker ink staining.The samples were inoculated and cultured on CHROMagar mediums containing 1% Tween 60 ( which was modified from Candida chromogenic media) in the atmospheric environment at 35 ℃.The suspected colonies were selected and cultured on both SDA plates containing 0.5% Tween 40 and SDA plates containing 0.5% Tween 60.The traditional phenotypic identification methods were used to identify the pure colonies,including staining,growth on Sabouraud agar plates,Tween test,decomposing Escalin,Catalase test,Tween precipitation test and castor oil test.Then the suspected colonies were identified by analyzing the sequences of 18s rRNAs.Results The isolation rate of Malasseziafurfur from lower respiratory tract secretions was 47.4% (63/133) and 63 strains were also identified as Malassezia furfur by traditional phenotypic identification methods combined with the 18s rRNA gene sequence analysis.Malassezia can be significantly distinguished from Candida by direct smear of the specimen with Parker ink staining.Conclusions Malassezia furfur was found as pink colonies on modified Candida chromogenic media which were significantly different from other Candida colonies.The isolation rate of lower respiratory tract secretions can be improved by modified Candida chromogenic media.The identification accuracy can be further improved by combining traditional phenotypic identification methods with 18s rRNA sequence analysis.
3.Study on nongonococcal genitourinary tract infections and drug resistance of Mycoplasma to antibiotics
Dongke CHEN ; Li CHEN ; Yunjian HU
Chinese Journal of Laboratory Medicine 2001;0(02):-
Objective To compare the isolation rate of Ureaplasma urealyticum(Uu), Mycoplasma hominis(Mh) and Chlamydia trachomatis(CT), and to analyze the resistance of Mh and Uu to 6 kinds of antibiotics. Methods CT in genitourinary tract of 1 059 NGU patients was detected by kit of VIDAS. Uu and Mh in genitourinary tract was detected by kit of IST. Results From 1 059 tested samples, the total positive percentage for Mycoplasma and Chlamydia was 36.3% and 5.6% respectively, 14.8% and 3.7% for Mycoplasma and Chlamydia from male samples, 52.6% and 7.2% for Mycoplasma and Chlamydia from female samples. The colony counting result showed that the number of female samples with colonies more than 104 cfu/ml was greater than that of male samples, 73.2% versus 60.3% for Uu and 30.5% versus 25% for Mh. The sensitivity of Mycoplasma to antimicrobial agents was as follows from high to low: Pristinamycine, Doxycycline, Josamycin, Tetracycline, Ofloxacin, Erythromycin. Conclusions The isolation of Mycoplasma was more than that of Chlamydia from patients with genitourinary tract infection.Resistance monitoring of Mycoplasma periodically played an important role in clinical drug treatment.
4.Evaluation and applicatipn of media for isolation of haemophilus
Dongke CHEN ; Yunjian HU ; Xiuzhen ZHANG
Chinese Journal of Laboratory Medicine 2001;24(1):28-30
Objective To select suitable media for increasing isolation rate of haemophilus.Methods Haemophilus was inoculated on seven types of media.The average growth index(GI) of Haemophilus was calculated and Haemophilus was isolated from 325 specimens of the respiratory tract and its isolation rate was compared with that media of brchoc and brchoc-V agare.Results The GI of media with 2% fresh yeast infusion and 50% of meat infusion was higher than that of those with no yeast and meat infusion.The GI of Haemophilus on BRchoc was higher than that of the BSchoc(P<0.001).The isolation rate of Haemophilus from 325 respiratory tract specimens on BRchoc-V was 77.2%,which was significantly higher than that on the medium BRchoc (32.0%).Conclusions BRchoc-V is a better medium for isolation of Haemophilus.This medium is effective to improve the isolation rate of Haemophilus.
5.A novel method for rapid identification and drug resistance of Moraxella catarrhalis
Dongke CHEN ; Ling ZHU ; Xiuzhen ZHANG
Chinese Journal of Laboratory Medicine 2001;0(01):-
Objective To establish a novel method for rapid identification and drug resistance of Moraxella catarrhalis, Different sourses of blood and the formula of chocklate agars were detected the Growth Index(GI). Methods Moraxella catarrhalis from specimens contaminated by microbial flora were isolated with a choclate agar with 50 mg/L vancomycin (CHOC-V) method. Nine media were inoculated,on which GI were calculated and compared. beta-Lactamase were determined by nitrocefin slip method. Results 228 strains of Moraxella catarrhalis and 203 strains of recent limbus bacteria were examined. The sensitivity of this method was 100%,and the specificity was 100%. The GI of Moraxella catarrhalis on chocklate agars and blood agars was higher than that of the BCA, NUA, MHA ( P
6.Integron-mediated multidrug resistance in clinical multi-reisistant Pseudomonas aeruginosa
Hongtao XU ; Dongke CHEN ; Xiuzhen ZHANG
Chinese Journal of Laboratory Medicine 2003;0(07):-
Objective To investigate the action of integron-mediated multidrug resistance in clinical multi-resistant Pseudomonas aeruginosa.Methods The strains of multi-resistant Pseudomonas aeruginosa were selected with K-B susceptibility method. The three-dimensional method was taken to differentiate the various beta-lactamases. The integron was determined by PCR with integron-specific primer. DNA sequencing was also used to analyze resistance-related gene in the integron in multi-resistant Pseudomonas aeruginosa.Results The positive rate of integron detection in multi-resistant Pseudomonas aeruginosa was 42.4%.Three kinds of different length integron were found .They were 750bp,1 000bp and 2 500bp and aadB,aadA2,aadB,aac6-II and PSE-1 were the resistance-related gene cassette in the integrons.Conclusions Integron took part in mutiple resistance in multi-resistant Pseudomonas aeruginosa.We should pay more attention to integron-mediated horizontal transference of mulidurg resistance to lessen the occurrence of multi-resistant strains.
7.Identification of Streptococcus pneumoniae resistant to optochin
Dongke CHEN ; Yan CHENG ; Xiuzhen ZHANG
Chinese Journal of Laboratory Medicine 2003;0(11):-
Objective Correctly identify Streptococcus pneumoniae resistant to optochin and other alpha hemolytic streptococcus susceptible to optochin.Methods Optochin susceptibility test, bile resolution test, latex agglutination test as well as some biochemical methods (VITEKCC4-GPI identifying cards,API-Strept identifying bar, VITEK TWO-GPC identifying cards) were applied.Results It was observed that 2 strains(0.3%)of Streptococcus pneumoniae out of 630 were resistant to optochin and 31strains of Streptococci, classfied as alpha hemolytic streptococci, susceptible to optochin, including 13 of S. mitis, 6 of S.oralis, 6 of S. twin, 3 of S. acidominimus, 2 of S.intermedius and 1 of S. constellatus. The inhibition zone of these alpha hemolytic streptococci susceptible sensitive to optochin was within the range of 14-17mm in diameter, in not 20 mm or more than 20 mm, compared with the inhibition zone of most strains of S.pneumoniae. Most of these alpha hemolytic streptococci (93.5%) susceptible to optochin showed highly resistance to benzoxazolecillin,to which most Streptococci (94%) showed sensitivity . Conclusion S.pneumoniae can be effectively identified by bile resolution test and latex agglutination test because of its high specificity with credible test results. API-Strept identifying bar and VITEK TWO-GPC identifying cards can be applied to identify S. pneumoniae resistant to optochin.
8.Fungus Isolation from Clinically Used Abacterial Body Fluid:Flora Distribution and Drug Resistance
Chunhe ZHANG ; Yan JIN ; Dongke CHEN
Chinese Journal of Nosocomiology 2004;0(10):-
OBJECTIVE To study fungal isolation and its drug resistance from abacterial body fluid.METHODS The abacterial body fluid for patients in our hospital was cultured by BacT Alert 120 and routine method.The strains which had been isolated were identified by development culture method and VITEK-YBC card or API-20C AUS reagent stripes.Furthermore,drug sensitive test was done by ATB FUNGUS2 drug sensitive reagent kit.RESULTS From the 898 samples with positive cultures of abacterial body fluid.8 species and 79 strains were isolated.Among the 79 fungal strains(8.8%),Candida albicans was 40 strains(50.6%),C.tropicalis was 12 strains(15.2%),C.glabrata was 11 strains(13.9%),C.parapsilosis was 9 strains(11.3%),C.guilliermondii was 4 strains(5.1%),C.krusei was 1 strain(1.3%),Cryptococcus were 1 strain(1.3%),and Mucor were 1 strain(1.3%).From them,13 strains(16.5%) were isolated in ICU,10 strains(12.7%) were in neurosurgical department,9 strains(11.4%) in oncological department,8 strains(10.1%) in urological surgery department,7 strains(8.9%) in thoracic surgery department,7 strains(8.9%) in pneumology department,6 strains(7.6%) in hematology department,5 strains(6.3%) in gerontology department,4 strains(5.1%) in orthopedic department,4 strains(5.1%) in endocrinology department,2 strains(2.5%) in nephrology department,and 4 strains(5.1%) in other units.The antifungal activity of amphotericin B,nystatin and flucytosine for fungus was quite perfect with sensitive ratio of 90%.But the drug resistance ratio to miconazole,ketoconazole and econazole was upward on 20-30%.CONCLUSIONS It′s important and necessary to monitor the circumstance of fungal infection and resistance of the pathogenic fungi due to its increased morbidity.
9.An investigation of factors influencing three dimensional test for be ta-lactamases
Dongke CHEN ; Zhimin ZHANG ; Xiuzhen ZHANG ;
Chinese Journal of Laboratory Medicine 2003;0(10):-
10 mm, inhibitor concentration
10.In vitro Antibacterial Activity of Home-made Rifamycin against Meticillin Resistant Staphylococcus and Other Pathogens of Clinical Isolates
Xiuzhen ZHANG ; Dongke CHEN ; Yunjian HU ; Tianzhi XUAN
Chinese Journal of Nosocomiology 2001;11(1):18-20
OBJECTIVE The in vitro activity of home-made rifamycin was investigated.METHODS Minimal inhibitory concentrations(MICs) were determined by agar dilution method using multipoint inoculator.RESULTS The results indicated that MIC50 and MIC90 of rifamycin against MRSA and MSSA were similar to vancomycin. The values were 1 and 2 mg/L, respectively. Rifamycin against MRSE was 4 times stronger than vancomycin.The value of MIC50 was 0.5 mg/L.The MIC50 of rifamycin against S.pneumoniae,Branhamella catarrhalis,and Listeria monocytogenes were 8,128 and 4 times lower than vancomycin, respectively.CONCLUSIONS There are good antibacterial activity of home-made rifamycin against meticillin resistant Staphyloccocus and the most species of clinical isolates,so can be used the infective diseases by MRSA and MRSE.