Candida auris: Diagnostic Challenges and Emerging Opportunities for the Clinical Microbiology Laboratory.

Purpose of Review: This review summarises the epidemiology of Candida auris infection and describes contemporary and emerging diagnostic methods for detection and identification of C. auris. Recent Findings: A fifth C. auris clade has been described. Diagnostic accuracy has improved with development of selective/differential media for C. auris. Advances in spectral databases of matrix-associated laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) systems have reduced misidentification. Direct detection of C. auris in clinical specimens using real time PCR is increasingly used, as is whole genome sequencing (WGS) to track nosocomial spread and to study phylogenetic relationships and drug resistance. Summary: C. auris is an important transmissible, nosocomial pathogen. The microbiological laboratory diagnostic capacity has extended beyond culture-based methods to include PCR and WGS. Microbiological techniques on the horizon include the use of MALDI-TOF MS for early echinocandin antifungal susceptibility testing (AST) and expansion of the versatile and information-rich WGS methods for outbreak investigation.

Candidaemia and a risk predictive model for overall mortality: a prospective multicentre study.

BACKGROUND: Candidaemia is associated with high mortality. Variables associated with mortality have been published previously, but not developed into a risk predictive model for mortality. We sought to describe the current epidemiology of candidaemia in Australia, analyse predictors of 30-day all-cause mortality, and develop and validate a mortality risk predictive model. METHODS: Adults with candidaemia were studied prospectively over 12 months at eight institutions. Clinical and laboratory variables at time of blood culture-positivity were subject to multivariate analysis for association with 30-day all-cause mortality. A predictive score for mortality was examined by area under receiver operator characteristic curves and a historical data set was used for validation. RESULTS: The median age of 133 patients with candidaemia was 62 years; 76 (57%) were male and 57 (43%) were female. Co-morbidities included underlying haematologic malignancy (n = 20; 15%), and solid organ malignancy in (n = 25; 19%); 55 (41%) were in an intensive care unit (ICU). Non-albicans Candida spp. accounted for 61% of cases (81/133). All-cause 30-day mortality was 31%. A gastrointestinal or unknown source was associated with higher overall mortality than an intravascular or urologic source (p < 0.01). A risk predictive score based on age > 65 years, ICU admission, chronic organ dysfunction, preceding surgery within 30 days, haematological malignancy, source of candidaemia and antibiotic therapy for ≥10 days stratified patients into < 20% or ≥ 20% predicted mortality. The model retained accuracy when validated against a historical dataset (n = 741). CONCLUSIONS: Mortality in patients with candidaemia remains high. A simple mortality risk predictive score stratifying patients with candidaemia into < 20% and ≥ 20% 30-day mortality is presented. This model uses information available at time of candidaemia diagnosis is easy to incorporate into decision support systems. Further validation of this model is warranted.

The epidemiology and clinical manifestations of mucormycosis: a systematic review and meta-analysis of case reports.

BACKGROUND: The epidemiology of mucormycosis in the era of modern diagnostics is relatively under-explored. OBJECTIVES: To examine the contemporary epidemiology, clinical manifestations, diagnosis and causative pathogens of mucormycosis. DATA SOURCES: Ovid MEDLINE and Ovid EMBASE from January 2000 to January 2017. STUDY ELIGIBILITY CRITERIA: Published case reports/series of proven/probable mucormycosis. PARTICIPANTS: Patients ≥18 years old. METHODS: Patient characteristics, disease manifestations and causative pathogens were summarized descriptively. Categorical variables were assessed by chi-square test or Fischer's exact test, and continuous variables by the Wilcoxon-Mann-Whitney or Kruskal-Wallis test. Risk factors for the different clinical manifestations of mucormycosis were identified using multivariate logistic regression. RESULTS: Initial database searches identified 3619 articles of which 600 (851 individual patient cases) were included in the final analysis. Diabetes mellitus was the commonest underlying condition (340/851, 40%) and was an independent risk for rhino-orbital-cerebral mucormycosis (odds ratio (OR) 2.49; 95% CI 1.77-3.54; p < 0.001). Underlying haematological malignancy was associated with disseminated infection (OR 3.86; 95% CI 1.78-8.37; p 0.001), whereas previous solid organ transplantation was associated with pulmonary (OR 3.19; 95% CI 1.50-6.82; p 0.003), gastrointestinal (OR 4.47; 95% CI 1.69-11.80; p 0.003), or disseminated (OR 4.20; 95% CI 1.68-10.46; p 0.002) mucormycosis. Eight genera (24 species) of Mucorales organisms were identified in 447/851 (53%) cases, of which Rhizopus spp. (213/447, 48%) was the most common. Compared with other genera, Rhizopus spp. was predominantly observed in patients with rhino-orbital-cerebral mucormycosis (75/213, 35% versus 34/234, 15%; p < 0.001). Death was reported in 389/851 (46%) patients. Mortality associated with Cunninghamella infections was significantly higher than those caused by other Mucorales (23/30, 71% versus 185/417, 44%; p < 0.001). However, Cunninghamella spp. were isolated primarily in patients with pulmonary (17/30, 57%) or disseminated disease (10/30, 33%). CONCLUSIONS: Findings from the current review have helped ascertain the association between various manifestations of mucormycosis, their respective predisposing factors and causative organisms.

Clinical effectiveness of itraconazole as antifungal prophylaxis in AML patients undergoing intensive chemotherapy in the modern era.

Antifungal prophylaxis regimens vary between centres, informed by local epidemiology and antifungal stewardship practices. The advantages of itraconazole over posaconazole prophylaxis include maintaining the utility of azole therapy for suspected breakthrough invasive fungal infection (bIFI). We examined the effectiveness and tolerability of itraconazole as prophylaxis in acute myeloid leukaemia (AML) patients. We sought to determine the rate of probable and proven bIFI in the context of itraconazole prophylaxis in a real-life setting. Eighty-four patients corresponded to 175 episodes of primary antifungal prophylaxis with itraconazole solution (200 mg twice daily) as prophylaxis supported by a dedicated clinical pharmacist during induction, re-induction and consolidation chemotherapy for AML between January 2010 and January 2014. Assessment of clinical course included blinded review of all radiology scans. Episodes of bIFI were categorised according to consensus criteria. A low rate of bIFI (6/175, 3.4 %) occurred with the use of itraconazole. Tolerance was excellent with adverse events consisting predominantly of deranged liver function tests reported in 7/175 (4 %). Therapeutic drug monitoring performed at clinicians' discretion demonstrated appropriate levels in 12/14 (86 %). Persisting fever and suspicion of invasive fungal infection (IFI) led to empiric antifungal therapy with voriconazole or caspofungin in 33/175 episodes (19 %), ceased after a median of 5 days following investigation in 16/175 (9 %). In this setting, itraconazole is effective and well-tolerated as prophylaxis. An additional benefit was seen in empiric therapy of suspected bIFI with amphotericin formulations kept in reserve. Local epidemiology is vital in guiding prophylaxis strategy.

Efficacy and safety of direct stenting in coronary angioplasty.

BACKGROUND: Direct stenting is the deployment of an intracoronary stent without lesion predilation. Potential advantages include shorter procedural time, lower contrast dose and reduced spiral dissections. There is also the potential financial benefit of less balloon and/or stent usage. Concern still exists among some operators, however, regarding failure of stent deployment and local complications. METHODS: Of 467 consecutive angioplasty cases at the Alfred Hospital between August 1, 1997 and May 22, 1998, direct stenting was attempted in 93 patients (20%). Interventionalist preference determined whether direct stenting was attempted. Vessels with excessive calcification, severe proximal tortuosity or small caliber were typically considered unsuitable for direct stenting. RESULTS: A total of 102 lesions (38 type A, 60 type B, and 4 type C) were treated with direct stenting. Initial deployment was successful in 98 of 102 lesions, with a further 3 lesions successfully stented following predilation. A stent was unable to be deployed in only 1 case; however, the lesion was treated with balloon angioplasty alone. The majority of lesions required only 1 stent (an average of 1.1 stents were used per lesion). Distal complications occurred in 5 patients. In 3 patients, a small distal dissection was successfully stented, and in 1 case embolization of debris occurred down the distal vessel, resulting in a small procedural myocardial infarction. Only 1 patient out of 93 (1%) developed a large distal dissection requiring the deployment of multiple stents, compared with 22 of the remaining 374 patients (5.9%) who underwent conventional angioplasty. This was a significant difference in favor of direct stenting (Chi-square, p < 0.05). When compared with a cohort of patients matched by lesion grade treated with conventional stenting, direct stenting used significantly less contrast per case (154 +/- 7.6 ml compared with 202 +/- 9.5 ml for conventional stenting; p = 0.0001). CONCLUSION: Direct stenting is a safe and effective method for treating coronary artery disease. In appropriately selected cases, it has a low rate of procedural failure and results in less contrast usage and fewer distal complications than conventional angioplasty and stenting.

Management of Coronary Restenosis via the Radial Artery: An Elegant Approach to the AchillesÕ Heel of PTCA.

In spite of many efforts, the most effective treatment for restenosis after coronary angioplasty remains repeat angioplasty. Although the second procedure is known to be at lower risk, it is usually performed by the same technique, thus requiring hospitalization. In such a group of patients, the feasibility of using the radial route for repeat coronary angiography and angioplasty when needed and the safety of early discharge were evaluated prospectively. Coronary angiography via the radial artery was attempted in 51 patients referred within 6 months of initial coronary angioplasty with the clinical suspicion of restenosis. Successful cannulation of the radial artery was possible in 48 (94%). Following placement of a 4 Fr arterial sheath, coronary angiography was completed successfully in all but one patient. Restenosis was confirmed angiographically in 25 patients (one via the femoral route) and a new lesion was observed in 3. Repeat angioplasty was attempted via the radial route (25 patients) or via the femoral route (one patient) using a fixed-wire balloon catheter through the 4 Fr diagnostic catheter (n=22). Angioplasty via the radial route including elective stent implantation (5 patients) was a technical success in 92% of the patients. Immediate arterial sheath withdrawal and mechanical compression of the radial artery provided satisfactory hemostasis after 186 +/- 126 minutes. The radial pulse was absent post-procedure without clinical consequence in 3 patients (6%). Of the 46 patients without a femoral artery puncture, 39 (85%) were discharged the same day without any cardiac or local complications. Thus, early discharge after repeat coronary angiography and angioplasty for restenosis is feasible and safe using the transradial route in the majority of patients.

Transesophageal echocardiographically facilitated early cardioversion from atrial fibrillation using short-term anticoagulation: final results of a prospective 4.5-year study.

OBJECTIVES: We sought to validate the safety of transesophageal echocardiographically guided early cardioversion in conjunction with short-term anticoagulation as a strategy for guiding early cardioversion in hospitalized patients with atrial fibrillation. BACKGROUND: Because atrial thrombi are poorly seen by conventional imaging techniques, several weeks of prophylactic anticoagulation is routinely prescribed before cardioversion. Transesophageal echocardiography is a superior test for identifying atrial thrombi; preliminary feasibility studies have supported its use to guide early cardioversion for patients in whom no thrombus is observed, but safety has not been validated in any large series. METHODS: All patients admitted to hospital with atrial fibrillation during a 4.5-year period were screened. The inclusion criterion was a clinical duration of atrial fibrillation > 2 days or of unknown duration. Patients received anticoagulation with heparin/warfarin and underwent conventional transthoracic echocardiography followed by transesophageal study. Patients in whom transesophageal echocardiography revealed no atrial thrombus underwent pharmacologic or electrical cardioversion followed by warfarin therapy for 1 month. Cardioversion was deferred in patients with evidence of atrial thrombi, and they received prolonged warfarin treatment. RESULTS: Two hundred thirty-three patients (86% of those eligible) agreed to participate, and 230 underwent transesophageal echocardiography. Transesophageal echocardiography identified 40 atrial thrombi (left atrium 34, right atrium 6) in 34 patients (15%). One hundred eighty-six (95%) of 196 patients without thrombi had successful cardioversion to sinus rhythm, all without prolonged anticoagulation, and none (0%, 95% confidence interval 0% to 1.6%) experienced a clinical thromboembolic event. Eighteen patients with atrial thrombi underwent uneventful cardioversion after prolonged anticoagulation. CONCLUSIONS: Compared with smaller series that have shown only feasibility, this large prospective and consecutive study of patients undergoing transesophageal echocardiographically facilitated early cardioversion in conjunction with short-term anticoagulation validates the safety of this strategy. This treatment algorithm has a safety profile similar to conventional therapy and minimizes both the period of anticoagulation and the overall duration of atrial fibrillation.

Intracardiac angiotensin-converting enzyme inhibition improves diastolic function in patients with left ventricular hypertrophy due to aortic stenosis.

BACKGROUND: Cardiac hypertrophy is associated with elevated intracardiac angiotensin-converting enzyme activity, which may contribute to diastolic dysfunction. METHODS AND RESULTS: We infused enalaprilat (0.05 mg/min) for 15 minutes into the left coronary arteries of 20 adult patients with left ventricular (LV) hypertrophy due to aortic stenosis (mean aortic valve area, 0.7 +/- 0.2 cm2) and 10 patients with dilated cardiomyopathy (mean ejection fraction, 35 +/- 4%) and assessed (1) simultaneous changes in LV micromanometer pressure and dimensions, (2) LV regional wall motion analyzed by the area method, and (3) Doppler flow-velocity profiles. Systemic neurohormonal activation did not occur with the selective left coronary artery infusion; there were no changes in plasma renin activity, angiotensin-converting enzyme activity, or atrial natriuretic peptide. In patients with aortic stenosis, LV end-diastolic pressure declined from 25 +/- 2 to 20 +/- 2 mm Hg (P < .05). LV pressure-volume and LV pressure-dimension relations showed downward shifts by ventriculography and echocardiography, respectively, indicating improved diastolic distensibility. Regional area change during isovolumic relaxation increased in the anterior segments perfused with enalaprilat but decreased in the inferior segments, indicating acceleration of isovolumic relaxation in the anterior segments and reciprocal shortening in the inferior segments. Regional peak filling rate increased in the anterior segments but not in the inferior segments, and the regional area stiffness constant decreased in the anterior segments but not in the inferior segments. There were no changes in heart rate, cardiac output, or right atrial pressure, excluding alterations in right ventricular/pericardial constraint. In contrast, in the patients with dilated cardiomyopathy the decrease in LV end-diastolic pressure from 22 +/- 2 to 18 +/- 2 mm Hg (P < .05) was accompanied by a significant fall in right atrial pressure (9 +/- 1 to 6 +/- 1 mm Hg), implicating alterations in pericardial constraint. The patients with dilated cardiomyopathy showed no improvement in regional diastolic relaxation, filling, or distensibility. CONCLUSIONS: Intracoronary enalaprilat at a dosage that did not cause systemic neurohormonal activation improved LV diastolic chamber distensibility and regional relaxation and filling in patients with LV hypertrophy due to aortic stenosis. In contrast, these effects of intracoronary enalaprilat on diastolic function were not observed in patients with dilated cardiomyopathy who did not have concentric hypertrophy. These observations support the hypothesis that the cardiac renin-angiotensin system is activated in patients with concentric pressure-overload hypertrophy and that this activation may contribute to impaired diastolic function.

Basic fibroblast growth factor improves myocardial function in chronically ischemic porcine hearts.

The effect of basic fibroblast growth factor (bFGF) administration on regional myocardial function and blood flow in chronically ischemic hearts was studied in 26 pigs instrumented with proximal circumflex coronary artery (LCX) ameroid constrictors. In 13 animals bFGF was administered extraluminally to the proximal left anterior descending (LAD) and LCX arteries with heparin-alginate beads and 13 other animal served as controls. bFGF-treated pigs showed a fourfold reduction in left ventricular infarct size compared to untreated controls (infarct size: 1.2 +/- 0.4% vs. 5.1 +/- 1.3% of LV mass, mean +/- SEM, P < 0.05). Percent fractional shortening (% FS) in the LCX area at rest was reduced compared with the LAD region in both bFGF and control pigs. However, there was better recovery in the LCX area after rapid pacing in bFGF-treated pigs (% FSLCX/% FSLAD, 22.9 +/- 7.3%-->30.5 +/- 8.5%, P < 0.05 vs. prepacing) than in controls (16.0 +/- 7.8%-->14.3 +/- 7.0%, P = NS). Furthermore, LV end-diastolic pressure rise with rapid pacing was less in bFGF-treated than control pigs (pre-pacing; pacing; post-pacing, 10 +/- 1; 17 +/- 3; 11 +/- 1* mmHg vs 10 +/- 1; 24 +/- 4; 15 +/- 1 mmHg, *P < 0.05 vs. control). Coronary blood flow in the LCX territory (normalized for LAD flow) was also better during pacing in bFGF-treated pigs than in controls. Thus, periadventitial administration of bFGF in a gradual coronary occlusion model in pigs results in improvement of coronary flow and reduction in infarct size in the compromised territory as well as in prevention of pacing-induced hemodynamic deterioration.

Efficacy of a low dose of cefotaxime in serious chest infections.

The optimal antibiotic dosage in serious chest infections is not established and commonly used regimens may well be excessive. We have compared the efficacy of a low dose of cefotaxime (2 g every 12 h) with a more usual dose (2 g every 8 h) in a prospective, randomized study of the treatment of chest infections in the seriously ill. Fifty intensive care unit patients received either regimen for five days. The two groups appeared demographically comparable. Clinical resolution occurred in 86 percent, no change occurred in 4 percent, and deterioration occurred in 10 percent. Microbiologic clearance occurred in 52 percent of those in whom a pathogen was isolated (46 percent of patients). There was no significant difference in clinical or microbiologic response between the two regimens. It is concluded that cefotaxime in a dose of 2 g twice daily is effective in the treatment of serious chest infections.

Uncertain relevance of gastric colonization in the seriously ill.

We have studied the temporal relationship for the same micro-organisms between gastric colonization and both nasopharyngeal colonization and major clinical infections in 100 consecutive, long-stay, intensive care patients. 67% of patients developed positive gastric cultures, mainly with aerobic Gram-negative bacilli and C. albicans; 33% developed positive nasopharyngeal cultures with similar organisms, but in only 8% was the same organism previously cultured from the stomach; 48% of patients developed infections, mainly respiratory, but commonly with different organisms. The presence of a positive gastric culture was not associated with gastric pH, bleeding, severity of illness, or mortality. The results fail to confirm that an ascending migration of organisms from the stomach is.frequent or that there is a relationship between gastric colonization and clinical infections. Firm therapeutic recommendation in these areas may be premature.