一起由宋内志贺菌引起的寄宿学校细菌性痢疾暴发病原学和流行病学分析

目的 对安徽省阜阳市某寄宿学校感染性腹泻暴发开展流行病学调查与病原学分析,为有效控制和处置疫情提供科学依据。方法 根据病例流行病学特征对2017年9月13-15日发病病例溯源假设进行检验,采集患者和厨师粪便、肛拭子、水样和食堂食品等进行致病菌分离与检测,对可疑致病菌进行生化鉴定、毒力基因检测、药敏试验、PFGE和多位点序列分型。结果 浅水井供水范围内宿舍楼的罹患率（3.41%）高于深水井（0.98%）,差异有统计学意义（χ²=17.215,P<0.001）。从患者样品中分离到16株宋内志贺菌,均携带ipaH基因且不携带set1基因,其中7株携带sen基因和ial基因。16株宋内志贺菌对氨苄西林、四环素、复方新诺明、头孢唑啉、头孢噻肟、庆大霉素、萘啶酸、链霉素高度耐药,9株宋内志贺菌对多西环素耐药。16株宋内志贺菌的PFGE带型相似度为100.0%,ST型均为ST152。结论 本次细菌性痢疾暴发的病原为宋内志贺菌,浅水井水可能为感染来源。     

北京地区福氏志贺菌Xv新亚型毒力基因与致病力研究

目的了解北京地区福氏志贺菌Xv新亚型生化特征、毒力基因与致病力。方法对分离自北京地区的61株福氏Xv新亚型志贺菌采用API生化板条鉴定,血清分型采用玻片凝集法,应用PCR技术检测其ipaH,sen,virF和ial毒力基因,采用脉冲场凝胶电泳(PFGE )了解分型特征,以鼠肺切片检测其致病力。结果61株福氏Xv志贺菌只发酵葡萄糖、甘露醇、密二糖和阿拉伯糖;血清凝集抗原结构式为(N : 7, 8); ipaH, sen, virF和ial,毒力基因携带率分别为100%,81.97%, 75.41%和80.30%;全部菌株PFGE分型可分为25种带型,鼠肺切片显示呈炎性改变。结论福氏Xv志贺菌毒力基因携带率高,表现出遗传多态性,具有侵袭力。     

山东省2011-2014年志贺氏菌分子分型及耐药性分析

  目的  通过对山东省2011-2014年分离的志贺氏菌（Shigella）进行血清、毒力基因、分子分型和药敏等分析,了解山东省志贺氏菌的特性及流行趋势。  方法  用玻片凝集法进行血清分型,PCR方法扩增相关毒力基因,用脉冲场凝胶电泳技术进行分子分型,采用微量肉汤稀释法测定菌株抗生素敏感性。  结果  44株志贺氏菌主要为福氏志贺氏菌（Shigella flexneri）（54.55%）和宋内志贺氏菌（Shigella sonnei）（43.18%）。ipaH、set1、sen、ial毒力基因携带率分别为100%、43.18%、56.82%、50.00%。经脉冲场凝胶电泳分型（pulsed field gel electrophoresis,PFGE）,福氏志贺氏菌被分为18种带型,且总体相似度偏低;宋内志贺氏菌被分为14种带型,且89.47%的菌株相似度在90%以上。44株志贺氏菌对15种抗生素中的14种均存在不同程度的耐药。93.18%的菌株为多重耐药菌株。  结论  山东省志贺氏菌以福氏和宋内血清群为主,毒力基因携带率高,有聚类分布出现,耐药严重,应加强对志贺氏菌菌型、溯源和耐药性的监测。     

河南省2009-2011年伤寒副伤寒沙门菌分子分型与耐药研究

目的 分析2009-2011年河南省伤寒副伤寒沙门菌临床分离株耐药状况与PFGE分型特征。方法 根据PulseNet公布的伤寒副伤寒沙门菌PFGE分型操作规程与美国临床实验室标准协会(CLSI)沙门菌K-B法药敏测试方案,对2009-2011年分离自河南省监测哨点医院78株伤寒副伤寒沙门菌进行抗生素药敏测试与PFGE分子分型。结果 78株伤寒副伤寒沙门菌对8类13种抗生素均有不同程度的耐药,62株为多重耐药菌株(79.5%),其中耐2～3种4株(5.1%),耐5～8种41株(52.6%),耐9～10种14株(17.9%),耐11～12种3株(3.8%);菌株对头孢类、喹诺酮类等5类抗生素耐药率总体呈上升趋势。经XbaⅠ酶切与PFGE后,获得14种带型,每种带型包含菌株数1～47株不等,相似度为66.03%～100.00%。结论 2000-2011年河南省临床分离的伤寒副伤寒沙门菌耐药状况普遍比较严重,PFGE带型呈现多样性的同时又具有较显著的优势带型特点,部分带型与其对应的耐药谱具有一定的关联性和聚集性。     

江苏省2010年宋内志贺菌耐药相关整合子分析及分子分型研究

目的分析江苏省2010年宋内志贺菌的整合子分布及分子分型特征。方法对江苏省2010年分离的33株宋内志贺菌采用K-B纸片法检测抗菌药物敏感性,联合PCR和限制性片段多态性(RFLP)进行整合子分类和可变区检测,利用测序技术判断整合子可变区耐药基因,应用脉冲场凝胶电泳(PFGE)进行分子同源性分析。结果宋内志贺菌多重耐药率为63.64%,对复方新诺明、四环素、萘啶酸和氨苄西林耐药率较高,分别为84.85%、75.76%、66.67%和63.64%。33株宋内志贺菌中51.52%的菌株检出I类整合子,其中4株可变区阳性,携带dfrA17-aadA5基因盒;81.82%的菌株检出II类整合子,携带dfrA1-sat1-aadA1基因盒;两类整合子同时存在时耐药性更为显著。PFGE图谱分为13个不同带型,同一带型菌株大多分散于江苏各地。结论整合子在宋内志贺菌中广泛存在,参与其多重耐药机制。多重耐药性在不同地区、不同克隆的菌株间扩散传播。     

北京市昌平区2012—2016年肠集聚性黏附大肠埃希氏菌耐药性、毒力基因及分子特征

目的了解昌平区肠集聚性黏附大肠埃希氏菌(EAEC)耐药性、毒力基因携带情况及分子特征。方法对2012—2016年北京市昌平区分离的15株EAEC毒株进行复核;以药敏实验检测菌株对16种抗菌药物的耐药性;以PCR法检测8种毒力的携带情况;采用多位点序列分型(MLST)及脉冲场凝胶电泳分型(PFGE)进行分子分型分析。结果 15株EAEC耐药率为100.0%,耐多药率为80.0%。每株携带2~5个毒力基因,共有10种毒力基因谱;8个毒力基因阳性率由高到低分别为aap(100.0%)、CVD432(93.3%)、aggA(60.0%)、agg3A(40.0%)、astA(33.3%)、pic(20.0%)、aafA(13.3%),未检出pet阳性。MLST分型分析将15株EAEC菌分为9个ST型,其中有4个新ST型(STcpEC1、STcpEC2、STcpEC3、STcpEC4),以STcpEC1为优势ST型(占33.3%)。PFGE分析得到13种PFGE带型,相同ST型菌株PFGE带型、毒力基因相似系数均较高。结论北京市昌平区近5年EAEC菌耐药率、多重耐药率较高,毒力基因aap、CVD432、aggA检出率高,STcpEC1为优势ST型,PFGE带型具有高度多态性。     

一起细菌性痢疾暴发疫情的病原检测及分子分型

目的:分析引起一起细菌性痢疾暴发疫情的宋内氏志贺菌菌株生化特征、抗生素抗性、毒力基因携带情况,并用脉冲场凝胶电泳(PFGE)进行分子分型、了解遗传相关性。方法:对该起疫情中分离的6株宋内氏志贺菌用K-B法进行药敏试验;用PCR方法检测其四种毒力基因携带情况;用XbaI酶切进行PFGE分子分型,结果用BioNumerics软件UPGMA方法进行聚类分析,观察菌株是否为同源株。结果:6株分离株对诺氟沙星、头孢噻肟、头孢噻吩、阿莫西林均敏感,对氨苄西林、庆大霉素、萘啶酸均耐药;6株菌均携带ipaH基因、均不携带set1基因,其中5株携带ial基因,其中3株携带sen基因;经XbaI酶切后产生同种带型,带型之间的相似性系数≥97.6%。结论:宋内氏志贺菌是引发此次疫情的病原,多重耐药,含毒力基因。菌株间遗传关系紧密,来自同一克隆群。     

一起菌痢疫情实验室检测分析

目的查明某校食物中毒事件的原因,为有效控制和处置疫情提供技术支持。方法采集患者粪便、肛拭子、呕吐物;厨师粪便、肛拭子;留样食物和水样进行致病菌检测,对分离的可疑致病菌进行鉴定、药敏试验、PCR毒力基因检测和脉冲场凝胶电泳(PFGE)分子分型比较溯源。结果从患者样品中分离出13株宋内志贺菌;经PFGE分子分型证明13株菌为同一带型;所有菌株均带有ipa H基因,11株携带ial基因,3株携带Sen基因,均不带有Set1基因;分离株对磺胺耐药率最高为61.54%。结论结合实验室结果和流行病学调查,可证实宋内志贺菌是引起这次菌痢疫情的病原菌。     

广东省2009－2013 年霍乱弧菌病原学特征分析

目的 分析广东省2009－2013 年霍乱病例及环境来源O1/O139 群霍乱弧菌病原学特征。方法 选取2009－2013 年广东省霍乱病例来源、环境（水体和海水产品）来源的O1/O139群霍乱弧菌。采用血清分型、抗菌药物敏感性试验、毒力基因PCR 检测和脉冲场凝胶电泳（PFGE）分子分型方法 , 研究不同来源的霍乱弧菌血清型、抗菌药物敏感性、毒力基因携带以及分子分型方面的异同。结果 2009－2013 年广东省共分离得到各类来源O1/O139 群霍乱弧菌190株（病例16 株, 外环境174 株）。病例来源菌株分为O1 群稻叶型（3 株）、小川型（7 株）和O139 群（6株）3 种菌型;其中10 株ctxA 基因阳性, 2 株小川型菌株携带不完整CTXΦ噬菌体;5 株菌对11 种抗菌药物完全敏感, 3 株对4 种抗菌药物表现出耐受。外环境来源菌株中53 株稻叶型, 22 株小川型和2 株O139 群菌株携带不完整CTXΦ噬菌体;2 株O139 菌株检出ctxA 基因阳性;25 株对≥4 种抗菌药物耐受, 其中有2 株同时对11 种抗菌药物中的7 种耐受, 以水产品中的稻叶型菌株为主（13株）。PFGE分子分型结果显示, 菌株经NotⅠ酶切后的PFGE型别表现出明显的多样性。稻叶型和O139 群病例菌株的带型聚集在同一个聚类中, 小川型病例菌株带型分散在不同的聚类中, 病例来源菌株与环境来源菌株的带型差别较大。结论 广东省O1/O139 群霍乱弧菌毒力基因和遗传特征复杂多样, 菌株多重耐药形势严峻, 需要加强菌株型别变异及耐药监测。     

江苏省2012-2015年伤寒/副伤寒沙门菌耐药及分子分型研究

目的 回顾性分析2012-2015年江苏省伤寒/副伤寒沙门菌的耐药表型和分子分型特征。方法 采集江苏省伤寒/副伤寒监测病例的血液和粪便标本,分离培养伤寒/副伤寒沙门菌后进行生化鉴定和血清分型;采用Kirby-Bauer纸片法检测菌株对抗菌药物的敏感性;应用PFGE技术对伤寒和甲型副伤寒沙门菌进行分子分型。结果 134株伤寒沙门菌和甲型副伤寒沙门菌对萘啶酸的耐药率最高,分别为61.2%和86.7%,其余抗生素的耐药率均低于15.0%。伤寒和甲型副伤寒沙门菌中只耐1种抗生素的菌株最多,多重耐药菌在伤寒沙门菌中占2.6%,而在甲型副伤寒沙门菌中占13.3%。2015年伤寒沙门菌的全敏感菌株构成比较2012年增加了44.3%,同年副伤寒沙门菌中出现了耐5种和6种抗生素的多重耐药株。甲型副伤寒沙门菌可分为8种PFGE型别,多重耐药株与其他菌株条带相似性低,不同型别与耐药谱有对应关系;伤寒沙门菌可分为68种PFGE型别,不同型别间变异度较大,与耐药谱无对应关系。结论 2012-2015年江苏省伤寒/副伤寒沙门菌对抗生素的耐药性总体随时间降低,耐药种类数有所增加。伤寒沙门菌株PFGE带型呈现多样性,无耐药谱对应性;而甲型副伤寒菌株PFGE带型较少,有耐药谱对应性。需要加强重点地区重点型别菌株的监测。     

Trends in predictors of death due to HIV-related causes among persons living with AIDS in New York City: 1993–2001

To examine trends in predictors of HIV-related mortality among cohorts of persons living with AIDS (PLWA) in New York City (NYC), nine calendar year-specific cohorts of PLWA were created from 1993 to 2001. Cohorts were defined as persons who had been alive at any time during that year and had been diagnosed with AIDS before the end of that year. Predictors of death because of HIV-related causes of death were assessed by examinnng year-specific, stratified death rates per 1,000 PLWA and adjusted relative risks (RRs) from proportional hazards models. We conducted an analysis of AIDS surveillance data PLWA in NYC between 1993 and 2001. Univariate and multivariate Cox proportional hazards models were constructed for each calendar year cohort to evaluate trends in the RR of HIV-related death over the subsequent 5 years, adjusting for sex, reace/ethnicity, age, transmission risk borough of residence, category of AIDS diagnosis [opportunistic illness (OI) or CD4 count <200 cells/μL], time since AIDS diagnosis, and CD4 count at time of AIDS diagnosis. Death rates due to all causes and HIV-related causes declined substantially during 1993–1997 and then stabilized in all subgroups of PLWA between 1998 and 2001. Beginning in 1995, differences in survival emerged in some subgroups, such that by 2001 (1) injecting drug users (IDUs) had poorer survival compared with men who have sex with men (MSM) [RR₂₀₀₁=2.1, 95% confidence intervals (95% CI)=1.8–2.4]; (2) black and Hispanic PLWA had a significantly higher risk of death than white PLWA (RR₂₀₀₁=1.4, 95% CI=1.2–1.6, RR₂₀₀₁=1.2, 95% CI=1.1–1.4, respectively, and (3) PLWA aged 60 and above had poorer survival compared with younger persons (RR₂₀₀₁=2.4, 95% CI=1.9–3.0), after adjustment for other factors. The observed disparities that began to emerge in 1995 may be attributable to differential effects of, access to, or usage of highly active antiretroviral therapy (HAART). More targeted studies are needed to determine why such disparities have emerged.     

Computer and internet use among urban African Americans with type 2 diabetes

Previous studies have identified a “digital divide” between African Americans and whites, with African Americans having substantially lower rates of Internet use. However, use of the Internet to access health information has not been sufficiently evaluated in this population. Therefore, we conducted a telephone survey to determine the prevalence of computer and Internet use among 457 African American adults with type 2 diabetes. Participants were 78% female, with a mean age of 57±11 years, and about one-third had a yearly income ≦$7,500. Forty percent of the participants reported having a computer at home and 46% reported knowing how to use a computer. Most participants (58%) reported that they had, at some point, used a computer, and of those, 40% reported that they used the computer to find health information. In a stratified analysis, participants with lower education levels (<high school) were less likely to have a computer; older participants, men, and individuals with lower education levels were less likely to know how to use a computer and to use it to search for health information (all P<.05). Nonetheless, of the participants who did not know how to use a computer, 66% reported that they would be willing to learn. In addition, 82% reported that they had friends or family in the neighborhood who would let them use a computer. Furthermore, 89% of participants reported that they would use a computer program to manage their diabetes if it were offered free of charge. These data show promise for the willingness of this under-served population to use computers and access health information using the Internet. New programs are needed to explore Internet-based interventions to improve self-management and diabetes care among African Americans.     

A vulnerable population in a time of crisis: Drug users and the attacks on the World Trade Center

In this article, we present preliminary findings from a qualitative study focused on the impact of the World Trade Center attacks on New York City residents who are current or former users of heroin, crack, and other forms of cocaine. In it, we present data describing their responses to and feelings about the attacks, changes in drug use after the attacks, and factors affecting changes in use. Our analysis is based on 57 open-ended interviews conducted between October 2001 and February 2002. The majority of study participants reported that the attacks had a significant emotional impact on them, causing anxiety, sadness, and anger. Several described practical impacts as well, including significant reductions in income. On September 11th and the weeks and months that followed, several participants who had been actively using did increase their use of heroin, crack, and/or other forms of cocaine. Reductions in use were, however, as common over time as were increases. There was some relapse among former users, but this was limited to those who had stopped using drugs within the 6 months immediately preceding the attacks. A diverse set of factors interacted to control use. For some participants, these factors were internal, relating to their individual motivations and drug use experiences. Other participants were essentially forced to limit use by marked reductions in income. For others, access to health and social service professionals, as well as drug treatment, proved to be key. Department of Family Medicine and Community Health at Montefiore Medical Center     

Absorption,metabolism and elimination of N,N-dimethylformamide in humans

Summary Excretion of N,N-dimethylformamide (DMF) and DMF metabolites N-hydroxymethyl-N-methylformamide (MF), N-hydroxymethyl-formamide (F) and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) has been monitored in the urine of volunteers during and after their 8-h exposure to DMF vapour at a concentration of 10, 30 and 60 mg · m^–3. The pulmonary ventilation in these experiments was typically about 101 · min^–1 and the retention in the respiratory tract was 90%. After exposure to 30 mg DMF · m^–3, the yield of compound determined in the urine represented 0.3% (DMF), 22.3% (MF), 13.2% (F) and 13.4% (AMCC) of the dose absorbed via the respiratory tract. The excretion curves of the particular compounds attained their maximum 6–8h (DMF), 6–8h (MF), 8–14h (F) and 24–34h (AMCC) after the start of the exposure. The half-times of excretion were approximately 2, 4, 7 and 23 h respectively. In contrast to slow elimination of AMCC after exposure to DMF, AMCC was eliminated rapidly after AMCC intake. This discrepancy could be explained by rate-limiting reversible protein binding of a reactive metabolic intermediate of DMF, possibly methylisocyanate.     

Antimicrobial antibodies in Danish slaughterhouse workers and greenhouse workers

Summary As a consequence of contact with animals and animal products slaughterhouse workers might be at risk of infection with pathogenic microorganisms. This hypothesis has been supported by some earlier studies. In this study 217 slaughtermen and a control group of 113 greenhouse workers were investigated for the prevalence of serum antibodies to Toxoplasma gondii, Campylobacter jejuni (IgA and IgG), Yersinia enterocolitica types 3 and 9, Yersinia pseudotuberculosis types I, II, III, IV, and V, Salmonella typhi, Salmonella paratyphi, Salmonella enteritidis, Salmonella typhimurium, and Borrelia burgdorferi. No significant differences were found concerning either frequency of positive tests or magnitude of titers. The prevalence of toxoplasma antibodies was remarkably high in both groups.     

Biological monitoring of workers exposed to<Emphasis Type="Italic"> N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylformamide in synthetic leather manufacturing factories in Korea

Objectives To investigate the relationship between N,N-dimethylformamide (DMF) exposure and excretion of urinary N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) and N-methylformamide (NMF) in workers at synthetic leather manufacturing factories in Korea, for the first time.Methods One-hundred forty-four male workers at nine synthetic leather manufacturing factories were surveyed. Exposure to DMF was evaluated through breathing zone air sampling followed by analysis via a gas chromatograph equipped with a flame ionization detector (GC-FID). The levels of NMF and AMCC were determined by a GC with a flame thermionic detector (GC-FTD). Urine samples were collected at the end of the workshift.Results and Conclusions Geometric mean of workplace air DMF and urinary NMF was 8.8 ppm and 47.5 mg/l, respectively, and the level of DMF and NMF was significantly correlated. The biological exposure limit for NMF (15 mg/ml) was exceeded in 89.5% of urine samples, and 37.9% of air samples exceeded the environmental DMF exposure limit (10 ppm), indicating a serious health risk to the employees of the synthetic leather industry in Korea. Exposure to 10 ppm DMF in the workplace air corresponded to a urinary NMF concentration of 53.4 mg/l. Alcohol intake the day before urine was sampled influenced NMF excretion into urine (40.5 mg/l NMF for the no-alcohol group and 94.6 mg/l for the group consuming more than 63.0 g alcohol/day). We could not find a significant relationship between air DMF and urinary AMCC concentration. Exposure to 10 ppm DMF corresponded to an AMCC concentration of 8.0 mg/l in the urine samples collected on the same day as the air was sampled.     

我国几种非嗜肺军团菌感染的血清流行病学研究

本文报告了1986年对我国五个地区994名健康成人、373名儿童和100例肺炎病人进行三种军团菌抗体检测的结果。健康成人抗体阳性率(≥1:16)Lm为9.26%,Ld为9.05%,Lg为3.32%。儿童Lm为5.36%,Ld为2.14%,Lg为3.75%。肺炎病人抗体阳性率以Ld最高(44%),Lm次之(23%),Lg均阴性。提示我国南方和北方地区人群中均存在这三种军团菌感染的可能性,应予以注意。     

Clinical and laboratory evidence of the importance of the tick D. marginatus as a vector of B. burgdorferi in some areas of sporadic Lyme disease in Bulgaria

56 adult ticks D. marginatus and 38 adult ticks H. punctata were sampled by the flagging method, transferred to the laboratory, dissected and tested for infection with Lyme disease spirochetes. 3 (7.9%) of the adult H. punctata and 2 (3.57%) of the adult D. marginatus were infected with B. burgdorferi (Bb). This report also presents the case of a patient, who developed Lyme disease symptoms after he had been bitten by a D. marginatus tick. The clinical diagnosis was confirmed by serological testing and by a biopsy, taken from the patient's skin lesion. The skin biopsy was examined under an electron microscope and Bb was found in the sections of the deeper strata of the dermis in two structural forms: (a) cylindrical bodies (protoplasm cylinder) with circular ends covered with a three-layered membrane; (b) granules, situated among the collagenous fibres either closely adhered to them or covered with a membrane. The result of the study demonstrates that in single cases in some ecosystems, ticks D. marginatus might be implicated in Bb transmission to humans as secondary vectors.     

成人灰色小克银汉霉侵袭性毛霉菌病1例并文献复习

目的 探讨灰色小克银汉霉感染导致成人毛霉菌病患者的临床特点及诊治方案。方法 总结某院血液内科收治的1例灰色小克银汉霉感染致成人侵袭性毛霉菌病患者的临床诊疗过程,并检索数据库相关文献进行复习。结果 患者男性,54岁,因“反复乏力1年余,加重伴发热1周”入院,肺组织病理检查可见宽大、不规则、无分隔的菌丝,形态学鉴定为毛霉菌,肺泡灌洗液及外周血宏基因组二代测序(mNGS)检测示灰色小克银汉霉,诊断为灰色小克银汉霉感染致侵袭性毛霉菌病,给予脂质体两性霉素B联合泊沙康唑、卡泊芬净治疗后感染获得控制。检索出符合条件的文献37篇,加上本病例,共纳入44例患者,其中男性26例,女性18例,中位年龄52.5(18～79)岁;基础疾病主要为血液系统疾病(65.9%,29例),进行造血干细胞或实体器官移植者14例;最常见的侵犯部位为肺、脑及皮肤,分别为36、9、9例;组织病理学、真菌培养、直接镜检及分子学检测阳性者分别为28、37、29、17例。41例患者接受了抗真菌治疗,其中8例联合手术治疗;30例死亡,病死率为68.2%,抗真菌治疗联合手术者生存率(62.5%,5/8)高于单独抗真菌治疗者(24.2%,...     

DNA relatedness,karyotyping and gene probing of Candida tropicalis,Candida albicans and its synonyms Candida stellatoidea and Candida Claussenii

Isolates of Candida albicans with varied phenotypes, including sucrose-negative variants (C. stellatoidea, serotypes A and B) and avirulent germ tube-negative forms (C. claussenii) showed significant (> 90%) DNA relatedness to classical C. albicans, but insignificant relatedness to C. tropicalis and sucrose-negative C. tropicalis. A transverse alternating-field gel electrophoresis procedure (TAFE) showed discrete karyotype patterns among the phenotypic variants of C. albicans including the sucrose-negative C. stellatoidea. The number of chromosome-sized DNA bands for C. tropicalis (7 bands) were within the range of bands observed for C. albicans (5 to 10 bands). The general DNA-migration pattern for C. albicans appeared distinct from that of C. tropicalis. An aspartyl proteinase (PrA) gene probe from C. albicans hybridized with chromosomal DNA from C. albicans, C. claussenii and C. stellatoidea but not with that from C. tropicalis.