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Objective:To analyze and compare the clinical characteristics and prognosis of imported patients infected with 2019 novel coronavirus (2019-nCoV) Omicron variants and Delta variants, so as to provide references for clinical diagnosis, treatment and epidemic prevention strategies.Methods:The patients with imported 2019-nCoV infection from August 1, 2021 to January 18, 2022 in Guangzhou Eighth People′s Hospital, Guangzhou Medical University were retrospectively analyzed. According to the whole genome sequencing of 2019-nCoV in nasal or throat swabs, they were divided into Omicron group and Delta group. The clinical characteristics, laboratory tests, antibody levels, viral nucleic acid (the cycle threshold (Ct) of N gene and open reading frame ( ORF) 1 ab), main treatment measures and clinical prognosis were analyzed in the two groups. Statistical analysis was performed using the rank sum test, chi-square test or Fisher′s exact test. Results:A total of 344 cases were enrolled, including 152 cases in the Delta group and 192 cases in the Omicron group, and there were 240 males (69.8%), with a median age of 33 years old. One hundred and two (29.7%) of those patients had underlying disease.Two hundred and seventy-one had completed full or booster vaccination. The overall full vaccination rate in Omicron group was 70.8%(136/192), which was higher than 51.3%(78/152) in Delta group. The proportion of mild patients in Omicron group was higher than that in Delta group (57.3%(110/192) vs 24.3%(37/152), respectively), and the proportions of common type and severe type were lower than those of the Delta group (33.9%(65/192) vs 55.3%(84/152) and 0(0/192) vs 10.5%(16/152)), the differences were all statistically significant ( χ2=37.64 and 15.84, respectively, Fisher′s exact test; all P<0.001). The duration and peak of fever in Omicron group were 1.5(1.0, 2.0) d and 38.1(37.8, 38.5) ℃, respectively, which were lower than those in Delta group (3.0(1.0, 4.8) d and 38.5(38.1, 39.0) ℃, respectively), and the differences were both statistically significant ( Z=-4.14 and -3.85, respectively, both P<0.001). The 2019-nCoV antibody IgG and the Ct values of virus nucleic acid N gene and ORF1 ab gene in the vaccinated Omicron group at admission were higher than those in the Delta group ( Z=-3.25, -2.18 and -2.82, respectively, all P<0.050). Compared with patients in Delta group, patients in Omicron group had lower proportion of receiving respiratory therapy support, shorter oxygen therapy time, shorter reversion time from admission to nucleic acid Ct value≥35 and shorter hospitalization time. The differences were all statistically significant ( χ2=47.86, Z=-5.41, -5.60 and -4.71, respectively, all P<0.001). There was no critical illness or 28-day death case in both groups. Conclusions:The severity of patients infected with Omicron variants is lighter than that of patients with Delta variants, and the viral nucleic acid has shorter conversion time, which is mainly related to the virulence of variant strain and vaccination.
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COVID-19 is a huge threat to global health. Due to the lack of definitive etiological therapeutics currently, effective disease monitoring is of high clinical value for better healthcare and management of the large number of COVID-19 patients. In this study, we recruited 37 COVID-19 patients, collected 176 blood samples upon diagnosis and during treatment, and analyzed cell-free DNA (cfDNA) in these samples. We report gross abnormalities in cfDNA of COVID-19 patients, including elevated GC content, altered molecule size and end motif patterns. More importantly, such cfDNA characteristics reflect patient-specific physiological conditions during treatment. Further analysis on tissue origin tracing of cfDNA reveals frequent tissue injuries in COVID-19 patients, which is supported by clinical diagnoses. Hence, we demonstrate the translational merit of cfDNA as valuable analyte for effective disease monitoring, as well as tissue injury assessment in COVID-19 patients.
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Objective:To investigate the incidence and risk factors of human cytomegalovirus (HCMV) reactivation in immunocompetent severe pneumonia patients with mechanical ventilation and their effects on clinical outcomes.Methods:A prospective observational study was conducted. Forty-eight immunocompetent patients requiring invasive mechanical ventilation due to severe pneumonia in the department of critical care medicine of the First Affiliated Hospital of Guangzhou Medical University from June 30th, 2017 to July 1st, 2018 were enrolled. Meanwhile, all cases were followed up until 90 days after inclusion and were required to quantitatively detect HCMV DNA in serum at regular weekly intervals until 28 days after transferring to intensive care unit (ICU). Patients were divided into HCMV reactivation group (≥5×10 5 copies/L) and non-reactivation group (<5×10 5 copies/L) based on HCMV DNA at any time point within 28 days. Demographic data, basic indicators, respiratory indicators, disease severity scores, laboratory indicators, complication and clinical outcomes of the two groups were collected and analyzed. Multivariate Logistic regression analysis was performed to screen independent risk factors for HCMV reactivation. Results:All 48 subjects were tested positive for HCMV immunoglobulin G (IgG), so HCMV seropositive rate was 100%. HCMV reactivation occurred in 10 patients within 28 days after admission to ICU, and the reactivation incidence of HCMV was 20.83%. There was no significant difference in gender, age, body mass index (BMI), underling disease reasons for ICU transfer (except sepsis), basic vital signs, disease severity scores, or laboratory findings including infection, immune, blood routine, liver, kidney and circulatory indicators except neutrophils count (NEU), hypersensitivity C-reactive protein(hs-CRP), hemoglobin (Hb), blood urea nitrogen (BUN), N-terminal pro-brain natriuretic peptide (NT-proBNP) between the two groups. The height (cm: 160±6 vs. 166±8), body weight (kg: 49.4±11.2 vs. 57.6±10.5), Hb (g/L: 87±18 vs. 104±24) in HCMV reactivation group were significantly lower than non-reactivation group, as well as NEU [×10 9/L:12.7 (9.9, 22.5) vs. 8.9 (6.2, 13.8)], hs-CRP [mg/L: 115.5 (85.2, 136.6) vs. 39.9 (17.5, 130.2)], BUN [mmol/L:13.7 (8.9, 21.5) vs. 7.1 (4.9, 10.5)] and NT-proBNP [ng/L: 6 751 (2 222, 25 449) vs. 1 469 (419, 4 571)] within 24 hours of admission to ICU. The prevalence of sepsis [60.0% (6/10) vs. 15.8% (6/38)], blood transfusion [100.0% (10/10) vs. 60.5% (23/38)], hospitalization expense [ten thousand yuan: 35.7 (25.3, 67.1) vs. 15.2 (10.4, 22.0)], 90-day all-cause mortality [70.0% (7/10) vs. 21.1% (8/38)], length of ICU stay [days: 26 (16, 66) vs. 14 (9, 19)], the duration of mechanical ventilation [days: 26 (19, 66) vs. 13 (8, 18)] in HCMV reactivation group were significantly higher than non-reactivation group, and there were significant statistical differences between the two groups (all P < 0.05). Logistic regression analysis showed that sepsis was an independent risk factor for HCMV reactivation in immunocompetent mechanical ventilation severe pneumonia patients with mechanical ventilation [odds ratio ( OR) = 9.35, 95% confidence interval (95% CI) was 1.72-50.86, P = 0.010]. Conclusions:HCMV infection is very common in immunocompetent severe pneumonia patients on mechanical ventilation and incidence of HCMV reactivation is high. Moreover, HCMV reactivation could adversely affect clinical prognoses, and sepsis may be a risk factor for HCMV reactivation.
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【Objective】 To establish a microbial limit test method for diatomite and pearlite, and verify its applicability. 【Methods】 According to the requirements of general rule 1105, Microbial Limit Test for Non Sterile Products of Pharmacopoeia of the People′s Republic of China (2020 Edition), the applicability test of microbial counting methods for three batches of perlite and diatomite was conducted before the microbial limit test of samples. The microbial growth of filter aid was analyzed and the recovery rate of each test bacterium was calculated. 【Results】 The ratio of the colony number of the test group minus the colony number of the test sample control group to the bacterial liquid control group was in the range of 0.5~2.0. 【Conclusion】 The method is accurate, reliable and can be used for microbial limit test of diatomite and perlite.
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The emergence of the novel human coronavirus, SARS-CoV-2, causes a global COVID-19 (coronavirus disease 2019) pandemic. Here, we have characterized and compared viral populations of SARS-CoV-2 among COVID-19 patients within and across households. Our work showed an active viral replication activity in the human respiratory tract and the co-existence of genetically distinct viruses within the same host. The inter-host comparison among viral populations further revealed a narrow transmission bottleneck between patients from the same households, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions. Author summaryIn this study, we compared SARS-CoV-2 populations of 13 Chinese COVID-19 patients. Those viral populations contained a considerable proportion of viral sub-genomic messenger RNAs (sgmRNA), reflecting an active viral replication activity in the respiratory tract tissues. The comparison of 66 identified intra-host variants further showed a low viral genetic distance between intra-household patients and a narrow transmission bottleneck size. Despite the co-existence of genetically distinct viruses within the same host, most intra-host minor variants were not shared between transmission pairs, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions. Furthermore, the narrow bottleneck and active viral activity in the respiratory tract show that the passage of a small number of virions can cause infection. Our data have therefore delivered a key genomic resource for the SARS-CoV-2 transmission research and enhanced our understanding of the evolutionary dynamics of SARS-CoV-2.
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BackgroundIn December 2019, human infection with a novel coronavirus, known as SARS-CoV-2, was identified in Wuhan, China. The mortality of critical illness was high in Wuhan. Information about critically ill patients with SARS-CoV-2 infection outside of Wuhan is scarce. We aimed to provide the clinical features, treatment, and prognosis of the critically ill patients with SARS-CoV-2 infection in Guangdong Province. MethodsIn this multi-centered, retrospective, observational study, we enrolled critically ill patients with SARS-CoV-2 pneumonia who were admitted to the intensive care unit (ICU) in Guangdong Province. Demographic data, symptoms, laboratory findings, comorbidities, treatments, and prognosis were collected. Data were compared between patients with and without intubation. ResultsForty-five critically ill patients with SARS-CoV-2 pneumonia were identified in 7 ICUs in Guangdong Province. The mean age was 56.7 years, and 29 patients (64.4%) were men. The most common symptoms at the onset of illness were high fever and cough. Majority of patients presented with lymphopenia and elevated lactate dehydrogenase. Treatment with antiviral drugs was initiated in all the patients. Thirty-seven patients (82.2%) had developed acute respiratory distress syndrome, and 13 (28.9%) septic shock. A total of 20 (44.4%) patients required intubation and 9 (20%) required extracorporeal membrane oxygenation. As of February 28th 2020, only one patient (2.2%) had died and half of them had discharged of ICU. ConclusionsInfection with SARS-CoV-2 in critical illness is characterized by fever, lymphopenia, acute respiratory failure and multiple organ dysfunction. Compared with critically ill patients infected with SARS-CoV-2 in Wuhan, the mortality of critically ill patients in Guangdong Province was relatively low. These data provide some general understandings and experience for the critical patients with SARS-CoV-2 outside of Wuhan.
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BackgroundAdministration of convalescent plasma may be of clinical benefit for treatment of severe acute viral respiratory infections. However, no clear evidence exists to support or oppose convalescent plasma use in clinical practice. We conducted a systematic review and meta-analysis to assess the evidence of randomized controlled trials (RCTs) in the convalescent plasma for the treatment of severe influenza. MethodsHealthcare databases were searched in February 2020. All records were screened against the eligibility criteria. Data extraction and risk of bias assessments were undertaken. The primary outcome was case-fatality rates by influenza. ResultsWe identified 5 RCTs of severe influenza. The pooled analyses showed no evidence for a reduction in mortality (Odds Ratio (OR) 1.06; 95% confidence interval (CI) 0.51-2.23; p = 0.87; I2 = 35%). We also found non-significant reductions in days in ICU and hospital, and days on mechanical ventilation. There seemed to have a biological benefit of increasing HAI titer levels and decreasing influenza B virus loads and cytokines after convalescent plasma treatment. No serious adverse events was reported between two groups. Studies were commonly of low risk of bias with high quality. ConclusionsConvalescent plasma appears safe but may not reduce mortality in severe influenza. This therapy should be studied within the context of a well-designed clinical trial for treatment of SARS-Cov-2 infection.
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Objective To investigate the value of N-terminal pro-B type natriuretic peptide (NT-proBNP) in predicting the outcome of spontaneous breathing trial (SBT) in ventilated elderly renal dysfunction patients. Methods The clinical data of patients who received mechanical ventilation in the Department of Critical Care Medicine of the First Affiliated Hospital of Guangzhou Medical University, Guangzhou Institute of Respiratory Disease from January 2011 to December 2014 were analyzed retrospectively. AU the patients conformed to the following criteria: age > 65 years, endogenous creatinine clearance rate (CCr) 72 hours and undergone at least one SBT. The patients were assigned to a SBT success group and a SBT failure group according to the outcome of first SBT. The following factors were recorded: gender, age, the underlying disease [chronic obstructive pulmonary disease (COPD), heart failure (HF) and others], body mass index (BMI), serum pre-albumin (pre-ALB), and acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, CCr and the concentration of the plasma NT-proBNP before SBT. Receiver operator characteristic curve (ROC) was plotted, and the predict value of NT-proBNP for the outcome of SBT in elder patients with kidney dysfunction was determined. Results A total of 58 patients with complete data were enrolled, with 41 cases in SBT success group, and 17 in SBT failure group. There were no significant differences in gender [male/female (cases): 26/15 vs. 13/4, χ2 = 0.930, P = 0.335], age (years: 70.2±7.4 vs. 74.6±10.1, t = 0.833, P = 0.339), the stratification of underlying diseases [COPD/HF/COPD+HF/others (cases): 15/9/13/4 vs. 7/3/5/2, χ2 = 0.242, P = 0.971], BMI (kg/m2: 25.2±11.3 vs. 27.4±6.43, t = 1.038, P = 0.221), pre-ALB (mg/L: 201.0±13.2 vs. 189.0±7.6, t = 0.688, P = 0.519), and APACHE Ⅱ score (12.2±3.2 vs. 13.5±6.3, t = 1.482, P = 0.147) and CCr (mL·min-1·1.73 m-2: 51.3±7.7 vs. 54.2±6.4, t = 0.711, P = 0.487) before SBT between SBT success group and SBT failure group. The concentration of plasma NT-proBNP in SBT failure group was significantly higher than that of the SBT success group (μg/L: 4.162±1.128 vs. 2.284±1.399, t = 4.905, P = 0.000). The area under ROC curve for plasma NT-proBNP in predicting successful SBT among elder patients with kidney dysfunction was 0.878, with 95% confidence interval (95%CI) 0.786 - 0.970. The cut-off method was used, and it was identified that the concentration of NT-proBNP < 3.350 μg/L as a predictor for successful SBT, with sensitivity of 82.4%, specificity of 87.8%, positive prediction value of 88.1% and negative predictive value of 76.5%. Conclusion The concentration of plasma NT-proBNP may increase in elderly kidney dysfunction patients undergoing ventilation, and NT-proBNP < 3.350 μg/L can serve as a good predictor for SBT success.
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ObjectiveTo explore the effect of prone position ventilation (PPV) on respiratory mechanics and prognosis in patients with acute respiratory distress syndrome (ARDS) concurrent with interstitial lung disease (ILD). Methods The data of 36 severe ARDS patients admitted to Department of Critical Care Medicine of the First Affiliated Hospital of Guangzhou Medical University from February 2013 to January 2015, were retrospectively analyzed. They were then divided into two groups according to the presence of ILD or not. The changes in respiratory mechanics and oxygenation indexes were compared before and after PPV treatment in all the patients. Kaplan-Meier method was applied to draw the 60-day survival curves of both groups.Results There were 17 cases with ILD among these 36 severe ARDS patients.① No significant difference was found in baseline data between ILD group and non-ILD group.② Respiratory mechanics and oxygenation pre-PPV and post-PPV: compared with pre-PPV, oxygenation index (PaO2/FiO2, mmHg, 1 mmHg = 0.133 kPa) post-PPV was significantly increased in both groups [ILD group : 132.0 (93.5, 172.0) vs. 118.7 (92.0, 147.8); non-ILD group: 126.1 (100.9, 170.0) vs. 109.2 (89.0, 135.0), bothP 0.05], and Crs was lower after PPV treatment in both groups, but without significant difference [non-ILD group: 22.7 (15.2, 27.1) vs. 24.3 (15.9, 48.9); ILD group: 16.2 (12.8, 25.6) vs. 18.9 (12.7, 27.3), bothP> 0.05].④ The 60-day mortality in ILD group was significantly higher than that in non-ILD group [88.2% (15/17) vs. 57.9% (11/19),P = 0.047). It was shown by Kaplan-Meier curves that 60-day survival patients in ILD group was significantly lower than those in non-ILD group (χ2 = 5.658,P = 0.017). Conclusions PPV can improve oxygenation in severe ARDS. Compared with non-ILD group, though the compliance of respiratory system in ILD group is increased during PPV, long-term effect is better in non-ILD group.
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A 56-year-old female patient of Han nationality presented with generalized erythema and vesicles for 6 days,as well as high fever for 2 days.Twenty days prior to hospitalization,the patient received surgical treatment combined with oral methazolamide and glucocorticoids for glaucoma.The patient had a history of allergy to sulfanilamides.On admission,the patient presented with generalized erythema,vesicles and occasional erosions with bilateral eyelid and oral involvement.Nikolsky's sign was positive.Wheezing sound was heard over the right lung.Genetic testing showed that HLA-B5901 allele was positive.The patient was diagnosed with methazolamide-induced toxic epidermal necrolysis (TEN) complicated by pneumonia,and managed with immunoglobulin (25 g/day,5 days),glucocorticoids (the largest dose equivalent to methylprednisolone 160 mg/day),fresh plasma,antibiotics,as well as other supporting and symptomatic treatments.The condition was controlled after 2 weeks,and the patient was cured and discharged from hospital after 25 days.The fact that the patient carried HLA-B5901 allele suggests that HLA-B5901 is strongly correlated with methazolamide-induced TEN or Stevens-Johnson syndrome in Chinese descendants or Han population,besides in Japanese and Korean descendants.
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Objective To investigate the value of the application of fibrobronchoscopy in extubation for patients suffering from acute exacerbation of chronic obstructive pulmonary disease(AECOPD)with low cough peak expiratory flow(CPEF). Methods A single-center prospective controlled study was conducted. The ventilated AECOPD patients who were cooperative at the time of extubation in Department of Critical Care Medicine of Guangzhou Institute of Respiratory Disease of Guangzhou Medical University from June 2009 to May 2014 were enrolled. All patients successfully passed the spontaneous breathing trial(SBT). Extubation was performed after determination of CPEF following energetic coughing. According to the CPEF,the patients were divided into CPEF≥60 L/min group (high CPEF group)and CPEF<60 L/min group(low CPEF group). After extubation,fibrobronchoscopic drainage was given to the patients in high CPEF group when necessary. Fibrobronchoscopic drainage was given to the patients in low CPEF group at least once a day,and the frequency of such treatment could be increased according to the patient's condition. If the patients did not require re-intubation within 48 hours,extubation was recorded as successful. The gender,age,acute physiology and chronic health evaluationⅡ(APACHEⅡ)score before extubation,ventilation time,the time of intensive care unit(ICU)stay,the mortality in ICU,the rate of re-intubation,the ability to cough and the frequency of application of fibrobronchoscopy after extubation were recorded. Results A total of 102 patients with AECOPD were enrolled,58 patients in high CPEF group and 44 in low CPEF group. Compared with high CPEF group,the mean age in low CPEF group was older(years:74.3±15.2 vs. 69.5±11.4,t=2.164,P=0.041),the time of ICU stay was significantly longer(days:20.1±11.2 vs. 17.4±7.3,t=2.274,P=0.030), but there was no significant difference in gender〔male/female(cases):35/9 vs. 45/13,χ2=0.057,P=0.812〕, APACHEⅡscore(11.9±1.9 vs. 10.3±4.2,t=1.290,P=0.200),mechanical ventilation time(days:14.8±10.8 vs. 13.3±9.6,t=0.677,P=0.501)and the rate of re-intubation〔18.18%(8/44)vs. 12.07%(7/58),χ2=1.412, P=0.235〕between low CPEF group and high CPEF group. The cough strength of patients in high CPEF group was almost alwaysstrong(52 cases),and in the low CPEF group,most of them wasmoderate(14 cases)orweak(26 cases). The frequency of application of fibrobronchoscopy in low CPEF group was higher than that in high CPEF group(times:4.1±1.8 vs. 1.3±0.9,t=2.626,P=0.011). All patients underwent weaning successfully,and no death occurred. Conclusion The application of fibrobronchoscopy in the extubated AECOPD patients with low CPEF can reduce the rate of re-intubation,avoid the prolonged ventilation,but cannot reduce the time of ICU stay.
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A 16-year-old male presented with a 11-year history of progressively enlarging erythema and crusting on the right cheek.Physical examination revealed an irregularly shaped,sharply marginated,dark erythematous patch sized 6 cm x 10 cm and plaques with mild verrucous proliferation.There were strip-like scar at the margin of lesions and multiple ulcers measuring 0.5 to 1 cm in diameter with firm crusts.No small jellycolored nodules were observed.Direct microscopy of multiple scrapings under the crusts showed many light brown,septate,branching and irregular hyphae.Olivaceous-black woolly colonies grew at 25 C and 35 C on Sabouraud's dextrose agar and potato dextrose agar; flask-shaped conidiogenous cells with funnel-shaped collarettes and ellipsoidal conidia arranged in flower-like shape were observed microscopically.PAS staining showed numerous septate and branching hyphae,pseudohyphae and yeast-like cells.There was a 99.73% similarity in the species-specific rDNA sequence between the isolate and phialophora verrucosa standard strain CDC-B2152.The patient was diagnosed with cutaneous phaeohyphomycosis caused by Phialophora verrucosa.The lesion subsided after treatment with amphotericin B and itraconazole,but recurred after drug withdrawal.Itraconazole and terbinafine were administered for the retreatment of this patient.
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Objective To investigate the effects of sepsis bundles in China.Method An observational study of 43 patients with severe pneumonia and septic shock admitted to the respiratory intertive care unit(1/11/2006-31/12/2007)was carried out.The selection criteria were in accordance with criteria set by International Conference On Sepsis in 2001.Implementation of 6 hours and 24 hours sepsis bundles was divided into 3 continu-ous phases consisting of education,trial,and application phase.A cohort of 43 patients with matched disease his-tory(1/1/2004-31/10/2006)was enrolled as control group.The percentages for categorical variables and mean±SD for continuous variables were reported.Chi-Square test.unpaired Student's t -test.paired-samples t test,univariate and multivariate logistic regression models were used.Statistical significance was defined as P<0.05.Results There were very little significant differences in basic characteristics of patients between the two groups.Compared with control group,the differences in serrum lactate,fluid resuscitation and fluid volume infused within 6 hours and blood glucose control in shock subgroup were significant(P values were 0.024,0.009,0.045,and 0.000,respectively).Compared with control group,the differences in respiratory rate and oxygenation index of bundles group at 72 hours later were significant(P values were 0.033 and 0.041,respectively).Compared with control group,the differences in APACHE Ⅱ score and predicted mortality in shock subgroup of bundles were sig-nificant(P values were 0.017 and 0.040,respectively).Compared with control group,the reduction in absolute mortality was 23.30% in bundles group(P=0.019).Conclusions Implementation of sepsis bundles con-tributes noticeably to the significant reduction in mortality of patients with severe pneumonia and septic shock.
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Objective To investigate the performance of DNA microarray in identifying 6 common Candida spp. and validating ERG11 mutations resulting in fluconazolc-resistance in Candida albicans. Methods Oligonucleotide probes were designed and synthesized targeting the species-specific sequence in the internal transcribed spacer 2 (ITS2) region of rDNA of Candida albicans, Candida tropicalis, Candida glabrata, Candida dubliniensis, Candida parapsilosis and Candida krusei, as well as 6 sequences embracing the following mutations respectively in ERG11 gene leading to fluconazole-resistance, i.c., T541C, A 1090G, C1361T, G1537A, G1547A, and T1559C, then arranged onto a chip. Twelve 50-base-pair oligonucleotides were artificially synthesized based on the above specific sequences, and utilized to hybridize with the DNA microarray. Thirty-lbur Candida strains, including 29 C. albicans, 1 Candida tropicalis, 1 Candida glabrata,1 Candida dubliniensis, 1 Candida parapsilosis and 1 Candida krusei, were detected with microarray. Genomic DNA was extracted from these tested strains and underwent multiple PCR for the amplification of ITS2 region and ERGI 1 gene. Sequencing was performed to analyze the sequence of ERG11 in 29 strains of C. albicans and the results were compared with those of DNA microarray hybridization. Results Multiple PCR successfully produced ITS2 fragment of 307-415 bp from all the 34 strains, as well as ERG11 fragment of 1712 bp from 29 C. albicans strains. DNA microarray hybridization offered the same results in species identification of the 34 strains with their given information, as well as in mutation detection of the 29 strains of C. albicans with ERG11 sequencing results. Also, the 6 synthesized oligonucleotides containing the muta- tions were identified precisely as T541C, A1090G, C1361T, G1537A, G1547A, and T1559C, and the 6 species specific oligonucleotieds were identified correctly as C. albicans, C. tropicalis, C. glabrata, C. dubliniensis, C. parapsilosis and C. krusei Both the sensitivity and the specificity of the microarray were 100%. Conclu- sion DNA microarray is a quite reliable method to identify Candida spp. and fluconazole resistance-associ- ated mutations in the ERG11 gene of C. albicans.
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Objeetive To detect ERG11 gene mutations in clinical isolares of Candida albicans resistant to fluconazole.and discuss their relationship with formation of drug resistance.Methods Clinical specimens were collected.CHROMagar mediuln and amplification of the fragment spanning the conserved sequence of 25S rDNA including some transposable introns.were used to identify subtype Candida albicans isolates.FIuconazole sensitivity was detected in vitro through microdilution and Rosco tablets.The other three fragment of ERG11 gene were amplified and followed by sequencing with resistant type strain ATCC 76615-19 and Candida albicans Darlington strain with two sensitive isolates as controh.Results Fifteen resistant isolates of Candida albicans were found,all of which were type A.Sixteen silent mutations and 11 missense mutations were detected.Mutations in ATCC 76615-19 and Darlington strain were same with what had been reported.In the 2 sensitive strains.G640A(E165K),A945C(E266D)and G1609A/G(V488I)occurred,as well as the other 9 silent mutations.Only G487T(A114S)and T916C(Y257H)existed in each of 14 resistant isolates.In the other one resistant isolate,T541C(Y132H),T495A(D116E),A530C (K128T)and T1493A(F449Y)occurred Mong with 8 silent mutations.Conclusions The occurrence of G487T(A114S)and 1916C(Y257H)in 14 isolates from different sources suggested they may involve in fluconazole resistance.The novel mutation T1493A(F449Y)can appear in resistant isolves of Candida albicans.