IL‐17 plays a central role in initiating experimental Candida albicans infection in mouse corneas

The pathogenesis of fungal infection in the cornea remains largely unclear. To understand how the immune system influences the progression of fungal infection in corneas, we inoculated immunocompetent BALB/c mice, neutrophil‐ or CD4⁺ T‐cell‐depleted BALB/c mice, and nude mice with Candida albicans. We found that only immunocompetent BALB/c mice developed typical Candida keratitis (CaK), while the other mouse strains lacked obvious clinical manifestations. Furthermore, CaK development was blocked in immunocompetent mice treated with anti‐IL‐17A or anti‐IL‐23p19 to neutralize IL‐17 activity. However, no significant effects were observed when Treg cells, γδ T cells, or IFN‐γ were immunodepleted. Upon infection, the corneas of BALB/c mice were infiltrated with IL‐17‐producing leukocytes, including neutrophils and, to a lesser degree, CD4⁺ T cells. In contrast, leukocyte recruitment to corneas was significantly diminished in nude mice. Indeed, nude mice produced much less chemokines (e.g. CXCL1, CXCL2, CXCL10, CXCL12, CCL2, and IL‐6) in response to inoculation. Remarkably, addition of CXCL2 during inoculation restored CaK induction in nude mice. In contrast to its therapeutic effect on CaK, neutralization of IL‐17 exacerbated Candida‐induced dermatitis in skin. We conclude that IL‐17, mainly produced by neutrophils and CD4⁺ T cells in the corneas, is essential in the pathogenesis of CaK.     

Detection of phospholipase activity of Candida albicans and non albicans isolated from women of reproductive age with vulvovaginal candidiasis in rural area

Background: Vulvovaginal candidiasis (VVC) is most common accounting for 17 to 39% of symptomatic women. Both Candida albicans and non albicans Candida species are involved in VVC. Amongst various virulence factors proposed for Candida, extracellular phospholipases is one of the virulence factor implicated in its pathogenicity. With this background the present study was carried out to find the prevalence of different Candida species and to detect phospholipase producing strains isolated from symptomatic women with VVC. Materials and Methods: At least two vaginal swabs from 156 women of reproductive age with abnormal vaginal discharge were collected. Direct microscopy and Gram’s stained smear examined for presence of budding yeast and pseudo mycelia followed by isolation and identification of Candida species. Extracellular phospholipase activity was studied by inoculating all isolates on Sabouraud’s dextrose egg yolk agar (SDA) medium. Results: Of the 156 women with curdy white discharge alone or in combination with other signs, 59 (37.82%) women showed laboratory evidence of VVC. A total of 31 (52.54%) women had curdy white discharge followed by 12 (20.33%) with other signs and symptoms. C. albicans (62.59%) and non albicans Candida (37.28%) in a ratio of 1.68:1 were isolated. Of the 37 strains of C. albians 30 (81.08%) showed the enzyme activity. Seventeen (56.66%) strains showed higher Pz value of < 0.70 (++++). Conclusion: Although there may be typical clinical presentation of Candidiasis. all the patients did not show laboratory evidence of infection. Pregnancy was found to be major risk factor for development of VVC. C. albicans was prevalent species but non albicans species were also frequently isolated. Extracellular phospholipase activity was seen in C. albicans and not in non albicans Candida isolates.     

Intracellular killing of Candida albicans by human polymorphonuclear leucocytes: comparison of three methods of assessment

Three different methods, [3H]uridine uptake, viable count and 51Cr-release were used to assess the intracellular survival of a strain of Candida albicans, 19321, which was lethal for mice injected intravenously. Intracellular survival 1 h after ingestion ranged from 50 to 80% depending on the method employed and the detergent used to lyse the phagocytes. Inhibition of uridine uptake by detergents used to lyse the phagocytes led to difficulty in assessment of intracellular killing by this method.     

The interplay between inflammasome activation and antifungal host defense

Fungal infections cause significant morbidity and mortality in humans, and they are a growing problem due to the increased usage of broad-spectrum antibiotics and immunosuppressive therapies. The equilibrium between the commensal microbial flora and the immune system that protects the host against invasive fungal infection is disturbed during disease, and understanding this disturbed balance is important to develop new therapeutic interventions for the treatment of fungal infection. In the context of tolerating fungi during colonization and eliciting a vigorous immune response to eliminate invading fungal pathogens when needed, the inflammasome has been identified as an integral component of antifungal host defense. It contributes to mucosal host defense by regulating T-helper 17 (Th17) cell responses, and contributes to protective responses such as neutrophil influx during fungal sepsis. Several aspects are important for understanding the role of the inflammasome for antifungal host defense, such as the role of fungal cell wall morphology and its components in triggering the inflammasome, the pattern recognition pathways and downstream signaling cascades involved in the activation of the inflammasome, and the effects of inflammasome activation during fungal infection. The future perspectives of inflammasome research in fungal immunology, with emphasis on targeting the inflammasome for the design of future immunotherapies, is also discussed.     

Inflammatory response and clinical course of adult patients with nosocomial bloodstream infections caused by Candida spp.

Candida spp. are an important cause of nosocomial bloodstream infection (nBSI) and are associated with significant morbidity and mortality. An historical cohort study was performed to evaluate the clinical course of 60 randomly selected adult patients with nBSIs caused by Candida spp. Patients with BSI caused by Candida albicans (n = 38) and non-albicans spp. (n = 22) were compared with 80 patients with Staphylococcus aureus BSI by serial systemic inflammatory response syndrome (SIRS) and APACHE II scores. The patients had a mean age of 52 years, the length of hospital stay before BSI averaged 21 days, and 57% of patients required care in an intensive care unit before BSI. The mean APACHE II score was 17 on the day of BSI, and 63% of BSIs were caused by C. albicans. Antifungal therapy within the first 24 h of onset of BSI was appropriate in 52% of patients. Septic shock occurred in 27% of patients, and severe sepsis in an additional 8%. Overall mortality was 42%, and the 7-day mortality rate was 27%. The inflammatory response and clinical course were similar for patients with BSI caused by C. albicans and non-albicans spp. In univariate analysis, progression to septic shock was correlated with high overall mortality, as was an APACHE II score >25 at the onset of BSI. In multivariate analysis, the APACHE II score at the onset of BSI and a systemic inflammatory response independently predicted overall mortality, but the 7-day mortality rate was only predicted independently by the APACHE II score. Clinical course and mortality in patients with Candida BSI were predicted by systemic inflammatory response and APACHE II score, but not by the infecting species.     

白色念珠菌诱导小鼠胸腺细胞凋亡

目的　研究白色念珠菌（ 白念菌） 在体内对小鼠胸腺细胞凋亡的诱导作用。方法　小鼠经尾静脉注射白念菌后,以流式细胞仪（ＦＣＭ） 分析、ＤＮＡ 琼脂糖凝胶电泳分析及细胞形态学改变为指标检测细胞凋亡。静脉注射ＮＯＳ 抑制剂观察对白念菌诱导胸腺细胞凋亡的影响。结果　白念菌能诱导小鼠胸腺细胞产生特征性的细胞凋亡形态学改变;流式细胞仪分析显示特征性的凋亡峰;琼脂糖凝胶电泳显示胸腺细胞出现典型的ＤＮＡ“梯状带”;用荧光染色（ＡＯ＋ ＥＢ） 以及ＦＣＭ 检测凋亡细胞百分率,发现白念菌注射后２４ 小时,胸腺细胞凋亡百分率随白念菌剂量增加而增高;用４ ×１０６ 白念菌经尾静脉注射后,胸腺细胞凋亡百分率于６ 小时开始增高,２４ 小时达高峰,以后迅速降低;小鼠胸腺萎缩,胸腺重量于１２ 小时明显降低,且于７２ 小时达到最低水平;ＮＯＳ 抑制剂氨基胍仅能部分抑制白念菌诱导的小鼠胸腺细胞凋亡;热灭活的白念菌不能诱导胸腺细胞凋亡。结论　白念菌菌血症能诱导小鼠胸腺细胞凋亡,而且呈时间和剂量依赖性;白念菌诱导小鼠胸腺细胞凋亡有赖于真菌的代谢;白念菌诱导小鼠胸腺细胞凋亡的过程可能与ＮＯ 部分相关。     

Adding Biotin to Parenteral Nutrition Solutions Without Lipid Accelerates the Growth of Candida albicans

Background: We have previously demonstrated that Candida albicans requires multivitamins (MVs) or lipid to increase rapidly in parenteral nutrition (PN) solutions. In this study, in detail, the effects of vitamins on the growth of C. albicans in PN solutions without lipid were investigated. Methods: In the 1st experiment, a commercial PN solution without lipid was supplemented with water-soluble vitamins (SVs: vitamins B₁, B₂, B₆, B₁₂ and C, folic acid, nicotinamide, biotin and panthenol), water-insoluble vitamins (IVs: vitamins A, D, E and K) or both (MVs). In the 2nd experiment, the test solutions were prepared by supplementing the PN solution with one of each or all of the SVs. In the 3rd experiment, another commercial peripheral PN (PPN) solution without lipid was supplemented with SVs, nicotinic acid, biotin or both nicotinic acid and biotin. In each of the experiments, a specified number of C. albicans organisms was added to each test solution, and all of the test solutions were allowed to stand at room temperature (23-26ºC). The number of C. albicans was counted at 0, 24, 48 and 72 hours after the addition of the organism. Results: In the 1st experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs, but increased slowly without the SVs, regardless of the addition of the IVs. In the 2nd experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs or biotin, but increased slowly with each of the other water-soluble vitamins. In the 3rd experiment, the C. albicans increased rapidly in the PPN solution supplemented with the SVs or biotin, but increased slowly with the addition of nicotinic acid. Conclusions: These results suggested that adding MVs or SVs to PN solutions without lipid promotes the growth of C. albicans, and that this effect is mostly attributable to biotin.     

Bronchoscopy as an indicator of tracheobronchial fungal infection in non-neutropenic intensive-care unit patients

We aimed to establish that a bronchoscopic view can be as reliable as microbiology, and support an empirical tracheobronchial fungal infection (TBFI) treatment decision. We retrospectively studied 95 respiratory failure patients with suspected TBFI admitted to the intensive-care unit (ICU) in 2008 with sticky secretions, hyperaemic mucosa, and whitish plaques on bronchoscopic view. Patients not suspected of having TBFI were chosen as a control group (n = 151). Broncheoalveolar lavage (BAL) fluid was cultured, and biopsy samples were taken from the lesions. Biopsy samples positive for fungi were defined as ‘proven', only BAL-positive (+ fungi) cases were ‘probable TBFI', and BAL-negative (– fungi) cases were ‘possible TBFI'. BAL (+ fungi) and BAL (– fungi) in the control group were defined as ‘colonization' and ‘no TBFI', respectively. The sensitivity, specificity and positive and negative predictive values of BAL (+ fungi) were 85.1% (63/74), 81.4% (140/172), 66.3% (63/95), and 92.7% (140/151), respectively. Biopsies were performed in 78 of 95 patients, and 28 were proven TBFI with fungal elements, and 100% were BAL (+ fungi). Probable TBFI was seen in 30 of 95 patients with BAL (+ fungi), and possible TBFI (BAL(– fungi)) in 25 of 95. Among the 95 patients, microbiology revealed fungi (90.5% Candida species; 9.5% Aspergillus) in 63 (66.3%). In the controls, the colonization and no TBFI rates were 11 of 151 and 140 of 151, respectively. Observing sticky secretions, hyperaemic mucosa and whitish plaques by bronchoscopy is faster than and may be as reliable as microbiology for diagnosing TBFI. These findings are relevant for empirical antifungal therapy in suspected TBFI patients in the ICU.     

Invasive Candidiasis in Children: Challenges Remain

How to cite this article: Baalaaji M. Invasive Candidiasis in Children: Challenges Remain. Indian J Crit Care Med 2022;26(6):667–668.     

Molecular heterogeneity of fluconazole-resistant and -susceptible oral Candida albicans isolates within a single geographic locale

The emergence of drug-resistant Candida albicans in immunocompromised patients is common. A disconcerting aspect of this phenomenon is the rapid emergence of C. albicans strains that are resistant to a widely used azole drug, fluconazole (FLZ). To understand the origin of FLZ-resistant yeast isolates, we investigated molecular profiles of 20 geographically related oral C. albicans isolates using three genotyping methods: randomly amplified polymorphic DNA-PCR, with six different primers (OBU1, OBU2, OBU3 RSD6, RSD11 and RSD12); electrophoretic karyotyping by pulsed-field gel electrophoresis; and HinfI restriction fragment analysis. Of the 20 isolates studied, 10 were FLZ- resistant and originated from patients with oral candidosis with a history of FLZ therapy, and the remainder were FLZ susceptible from individuals with oral candidosis, but without a history of FLZ therapy. A composite genotype was generated for each strain by combining molecular types derived from the three independent molecular methods. The composite profiles indicated genetic diversity amongst both the FLZ-resistant as well as -sensitive isolates, and no specific features emerged distinguishing the drug-resistant and -sensitive groups. These observations cast doubt on the theory of a clonal origin of FLZ-resistant C. albicans isolates.     

新生儿重症监护病房真菌血症病原学及临床分析

目的探讨自2004年1月至2008年12月我院新生儿重症监护病房获得性真菌血症病原学及临床特征,为真菌血症防治提供依据。方法回顾分析5年中新生儿重症监护室发生的33例真菌血症的病原学和临床资料。结果33例真菌血症均为医院获得感染的假丝酵母菌,其中白色假丝酵母菌17株、热带假丝酵母菌10株、近平滑假丝酵母菌5株、光滑假丝酵母菌1株。结论假丝酵母菌属是新生儿重症监护病房真菌血症的主要致病菌,以白色假丝酵母菌最常见,但非白色假丝酵母菌也占较大比例;真菌血症与早产、极低体重儿、机械通气、静脉导管、全胃肠外营养等因素有关。5-氟脲嘧啶、伊曲康唑、两性霉素B和氟康唑对假丝酵母菌耐药性较低,氟康唑是治疗假丝酵母菌属的有效药物。     

Macrophages activation by a purified fraction,free of nordihydroguaiaretic acid (NDGA), from Larrea divaricata Cav. as a potential novel therapy against Candida albicans

Larrea divaricata Cav. (jarilla) is a plant with well-documented applications in Argentinean folk medicine. In order to determine if the treatment with a purified fraction named F1 was capable to maintain a state of priming of macrophages after 15 days of mice infection with Candida albicans. Infected and uninfected mice were used. The effect of F1 on: cytosolic protein levels, apoptosis, phagocytosis, reactive oxygen species production, nitric oxide (NO), cell activity, lysosomal activity and the tissue fungal burden were studied. The results showed that F1 increased macrophages yeast phagocytosis and reactive oxygen species and NO production. All these effects were related to a decrease of cell activity and possible apoptosis. In conclusion, it was observed that F1 could induce a state of long-term activation of macrophages, since we observed increased activity of macrophages 15 days after infection, and it could be related to the elimination of C. albicans. These data may suggest that F1 fraction could be useful against disseminated candidiasis in patients and further studies on this field are desirable.     

食管癌患者术后肠内营养临床效果分析

目的观察肠内营养(EN)与肠外营养(PN)对食管癌患者术后临床效果的影响,评价食管癌术后早期肠内营养支持的临床意义。方法肠外营养组(PN组)术后每日行完全肠外营养支持直到经口进食;肠内营养组(EN组)术后第1日以静脉支持为主,第2日开始经鼻肠营养管滴入肠内营养制剂瑞素,并逐步增大剂量,减少静脉支持。在术后各个不同时间点分别进行各项指标及营养免疫功能指标的测定。结果 EN组术后排气、排便时间和术后平均住院时间均短于PN组。术后EN组营养和免疫功能指标均优于PN组。结论食管癌术后早期肠内营养可促进小肠运动功能恢复,可有效改善食管癌患者术后营养状况和免疫功能。     

Enhanced IgE response to Candida albicans in postoperative invasive candidiasis

Background Invasive candidiasis is a life-threatening complication problem in postoperative and immunocompromized patients, e.g. those treated by intensive care. Candida is frequently cultured from the mucous membranes of hospital patients and fungal cultures offer httle diagnostic help. Other diagnostic methods, such as blood cultures, serology and diagnostic imaging techniques produce results too late and, if positive, low sensitivity. Objective To study the value of Candida-specific antibodies, especially those of IgE class, in diagnosing invasive Candida infection. Methods The immunoglobulins IgE, IgG and IgM responses to antigens of Candida albicans in the sera of 14 patients with culture, biopsy and/or autopsy proven postoperative invasive candidiasis and of 11 colonized and 19 non-colonized operated patients were studied by mannan radioallergosorbent test (RAST), mannan enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results Detection of IgE antibodies to C. albicans polysaccharide (mannan) and protein antigens proved specific and sensitive in diagnostics of invasive candidiasis after major abdominal surgery. IgE rose early in the course of the infection and the method made a clear distinction between invasive infection and mucous colonization. Immunoblotting for protein antibodies was most sensitive while nitrocellulose-RAST for mannan antibodies was most specific. The combined use of immunoblotting and RAST increased the sensitivity and the specificity. Determinations of anti-Candida IgG and IgM antibodies had low sensitivity and specificity. Conclusion Critically ill patients with invasive candidiasis develop IgE antibodies to Candida antigens probably because of disturbed TH₁/TH₂ responses. Determination of specific IgE antibodies can be used as a diagnostic aid in the early stage of invasive Candida infection.     

抗白色念珠菌IgY的稳定性及体内抗感染活性研究

目的观察抗白色念珠菌IgY的稳定性及体内抗感染活性。方法水稀释法从免疫鸡卵黄提取抗白色念珠菌IgY,酶联免疫吸附试验间接法和微量间接血凝试验测定其抗体效价,并观察其对热、酸碱度、胰蛋白酶及冻存时间的稳定性和对小鼠腹腔感染白色念珠菌的保护效果。结果水稀释法提取的抗白色念珠菌IgY效价为1∶5120;IgY在25~70℃处理15min,pH3.0~11.0、37℃处理2h,或普通冰箱冻存6年效价改变不明显;在37℃下与胰蛋白酶作用2h效价仍保持50%。IgY对免疫功能低下小鼠腹腔感染白色念珠菌有明显的保护作用(P<0.01)。结论抗白色念珠菌IgY具有良好的稳定性和较好的体内抗感染活性。     

早期肠内肠外营养支持对结直肠癌患者术后影响

目的比较不同营养支持途径对结直肠癌患者术后营养指标的影响。方法回顾性分析自2010年1月至2014年1月84例胃癌和结直肠癌根治术后患者的临床资料,其中肠内营养组(EN组)43例和肠外营养组(PN组)41例,分别于术后第1天开始进行肠内和肠外营养,2组患者基本等氮、等热量;每组患者手术前后和术后第7天检测血清白蛋白(ALB)、转铁蛋白(TF)、前白蛋白(PA),观察术后不良反应、胃肠道功能恢复时间、感染、营养支持费用等情况。结果术后EN组和PN组的营养指标和不良反应发生率比较无显著性差异(P0.05);EN组感染发生率低(P0.01)且胃肠道功能恢复时间早(P0.01),与PN组相比较差异具有统计学意义。结论结直肠癌患者术后采用肠内营养方案,不良反应少、胃肠道功能恢复快。     

Comparison of adherence of Candida albicans and Candida parapsilosis to silicone catheters in vitro and in vivo

Objective  Although Candida parapsilosis has been associated with device-related infections in the clinical settings, factors that contribute to this association have not been previously examined. The objectives of this study were to compare in vitro and in vivo the adherence to silicone catheters of: (1) Candida albicans vs. C. parapsilosis , and (2) invasive vs. colonizing isolates of C. albicans and C. parapsilosis .
Methods  The records of 840 patients who had had Candida species isolated at three teaching hospitals during a three-month period were reviewed. A total of 20 clinical isolates of each of C. parapsilosis and C. albicans were examined for their adherence to silicone catheters in vitro and in a rabbit model of percutaneously placed catheters. For each Candida species, ten invasive isolates that had caused clinical device-related infection and 10 colonizing isolates that had caused only device colonization were studied.
Results  Candida parapsilosis accounted for <5% of yeast isolates from all sites, while three-quarters were C. albicans . Candida parapsilosis was isolated proportionately more often from blood and/or devices than C. albicans (34.3% vs. 8.5%, respectively, P  < 0.0001). There were no significant differences in the degrees of adherence in vitro and in vivo between C. albicans and C. parapsilosis or between invasive and colonizing Candida .
Conclusion  Although C. parapsilosis was isolated proportionately more often from blood and/or devices than C. albicans in our studied population, there was no significant difference in the adherence of the two Candida species to silicone, nor between invasive and colonizing Candida in our in vitro and in vivo models. Factors other than microbial adherence may help explain the observed association of C. parapsilosis with device-related infections.     

早期肠内营养对食管癌手术疗效的影响研究

目的探讨食管癌术后早期肠内营养的安全性和有效性。方法选择98例食管癌手术患者，年龄46～69岁，ASAⅠ-Ⅱ级，随机分成两组，早期肠内营养支持治疗组50例，常规液体治疗组48例，观察两组患者术后并发症的发生情况，手术切口愈合情况，肠蠕动情况以及术前术后体重下降情况，免疫学指标变化和住院天数比较。结果早期肠内营养支持治疗组在减少术后并发症的发生、促进手术切口愈合、肠蠕动恢复以及免疫学指标改善等方面均优于常规液体治疗组（P〈0．05）。结论对食管癌手术患者早期肠内营养支持治疗是可行的方法，可以明显改善患者的营养状况，减少住院天数，是一种比较实用的治疗方法。     

特比萘芬与氟康唑或伊曲康唑联合对氟康唑诱导耐药稳定白念珠菌的影响

目的探讨特比萘芬与氟康唑或伊曲康唑联合抗氟康唑诱导产生的耐药稳定白念珠菌的作用.方法采用多步诱导法,在YEPD培养基中,利用氟康唑诱导白念珠菌敏感株产生耐药稳定菌株.根据美国国家临床实验标准委员会（NCCLS）制定的标准,采用棋盘微量稀释法测定特比萘芬与氟康唑或伊曲康唑对耐药稳定菌株的联合药敏试验,并对诱导耐药稳定菌株ERG11基因的编码区序列进行DNA测序.结果临床敏感菌株和标准敏感菌株能被诱导形成耐药菌株,但大部分不稳定,诱导耐药稳定株ERG11基因的编码区DNA测序有突变点存在,特比萘芬与氟康唑或伊曲康唑联用对诱导耐药稳定株可产生协同作用.结论特比萘芬与氟康唑或伊曲康唑联合应用对基因突变产生的耐药株有协同作用,可阻止或延迟氟康唑诱导的耐药性白念珠菌菌株的产生.