Laboratory Diagnosis of Infections in Cancer Patients: Challenges and Opportunities

Analytical and clinical evaluation of the cobas Epstein-Barr virus test at a tertiary care cancer hospital

BACKGROUND

Epstein-Barr Virus (EBV) viral loads in hematopoietic stem cell transplant (HSCT) recipients are typically monitored using quantitative molecular assays. The Cobas EBV test (Roche Molecular, Pleasanton, CA) has recently been FDA-cleared for the monitoring of EBV viral loads in plasma samples of transplant patients. In this study, we compared the viral loads obtained by a laboratory-developed test (EBV LDT) using Altona Analyte specific reagents (ASR) to those obtained on the Cobas EBV test.

METHODS

The analytical performance of the assay was established using the EBV verification panel from Exact Diagnostics and the EBV ATCC strain B95-8. The clinical evaluation was performed using 343 plasma samples initially tested on the EBV LDT.

RESULTS

The analytical sensitivity (<18.8 IU/mL), precision (SD < 0.17 log) and linear range (35.0 IU/mL to 1E + 08 IU/mL) of the Cobas EBV assay established by the manufacturers were confirmed. The strength of the qualitative agreement was substantial between the cobas EBV and the EBV LDT (85.6 %; κ = 0.71) and almost perfect when discordant results were resolved (96.4 %; κ = 0.93). The quantitative agreement was moderate (82.9 %; κ = 0.53) with the viral load obtained on the Cobas EBV test being lower across the linear range of the two tests (mean log difference of 1.0). While the absolute values of the viral loads were markedly different, the overall trends observed in patients with multiple consecutive results were similar between the two tests.

CONCLUSIONS

The Cobas EBV test provides an accurate and valid, in vitro diagnostic (IVD) option for monitoring of EBV viral loads in transplant patients and should provide an opportunity for increased standardization and commutability of tests results across laboratories.

High mortality associated with inappropriate initial antibiotic therapy in hematological malignancies with Klebsiella pneumoniae bloodstream infections

Bloodstream infections caused by multidrug-resistant organisms such as Klebsiella pneumoniae are a significant challenge in managing hematological malignancies. This study aims to characterize the epidemiology of Klebsiella pneumoniae bloodstream infections specifically in patients with hematological malignancies, delineate the patterns of initial antibiotic therapy, assess the prevalence of resistant strains, identify risk factors for these resistant strains, and evaluate factors influencing patient outcomes. A retrospective analysis was conducted at a single center from January 2017 to December 2020, focusing on 182 patients with hematological malignancies who developed Klebsiella pneumoniae bloodstream infections. We compared the 30-day mortality rates between patients receiving appropriate and inappropriate antibiotic treatments, including the effectiveness of both single-drug and combination therapies. Kaplan-Meier survival analysis and multivariate logistic and Cox regression were used to identify factors influencing mortality risk. The 30-day all-cause mortality rate was 30.2% for all patients. The 30-day all-cause mortality rates were 77.2% and 8.8% in patients who received inappropriate initial treatment and appropriate initial treatment (p < 0.001). Inappropriate initial treatment significantly influenced mortality and was a key predictor of 30-day mortality, along with septic shock and previous intensive care unit (ICU) stays. Patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections exhibited more severe clinical symptoms compared to the CSKP group. The study demonstrates a significant association between empirical carbapenem administration and the escalating prevalence of CRKP and multidrug-resistant K. pneumoniae (MDR-KP) infections. Furthermore, the study identified inappropriate initial antibiotic therapy, septic shock, and ICU admission as independent risk factors for 30-day mortality.

Gaps in diagnosing suspected infection in immunocompromised children with cancer: A systematic review

While the survival of children with cancer has improved over time, infection remains a major morbidity and mortality risk. We conducted a systematic literature review to determine the unmet needs in diagnosing infection in immunocompromised children with cancer. The comprehensive search strategy followed the guidelines established by the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 statement, and spanned multiple bibliographic databases and other public sources from January 1, 2012 to June 23, 2022. From 5188 records, 34 unique pediatric-focused studies met inclusion criteria. This review highlights the lack of published data on infectious disease testing in pediatric oncology patients, and the need for well-designed clinical impact and cost-effectiveness studies of both existing and novel diagnostic platforms. Such studies are necessary to optimize diagnostic and antimicrobial stewardship, leading to improvement in patient outcomes.

A Systematic Literature Review to Identify Diagnostic Gaps in Managing Immunocompromised Patients With Cancer and Suspected Infection

Patients with cancer are increasingly vulnerable to infections, which may be more severe than in the general population. Improvements in rapid and timely diagnosis to optimize management are needed. We conducted a systematic literature review to determine the unmet need in diagnosing acute infections in immunocompromised patients with cancer and identified 50 eligible studies from 5188 records between 1 January 2012 and 23 June 2022. There was considerable heterogeneity in study designs and parameters, laboratory methods and definitions, and assessed outcomes, with limited evaluation of diagnostic impact on clinical outcomes. Culture remains the primary diagnostic strategy. Fewer studies employing molecular technologies exist, but emerging literature suggests that pathogen-agnostic molecular tests may add to the diagnostic armamentarium. Well-designed clinical studies using standardized methodologies are needed to better evaluate performance characteristics and clinical and economic impacts of emerging diagnostic techniques to improve patient outcomes.

Hypoxia-Directed and Self-Immolative Theranostic Agent: Imaging and Treatment of Cancer and Bacterial Infections

The impact of bacteria on cancer progression and treatment is becoming increasingly recognized. Cancer-associated bacteria are linked to metastases, reduced efficacy, and survival challenges. In this study, we present a sensitive hypoxia-activated prodrug, NR-NO2, which comprises an antibiotic combined with a chemotherapeutic. This prodrug demonstrates rapid and robust fluorescence enhancement and exhibits potent antibacterial activity against both Gram-positive and Gram-negative bacteria as well as tumor cells. Upon activation, NR-NO2 produces a distinct "fluorescence-on" signal, enabling real-time drug release monitoring. By leveraging elevated nitroreductase in cancer cells, NR-NO2 gives rise to heightened bacterial cytotoxicity while sparing normal cells. In A549 solid tumor-bearing mice, NR-NO2 selectively accumulated at tumor sites, displaying fluorescence signals under hypoxia superior to those of a corresponding prodrug-like control. These findings highlight the potential of NR-NO2 as a promising cancer therapy prodrug that benefits from targeted release, antibacterial impact, and imaging-based guidance.

Construction of a red emission fluorescent probe for selectively detection of cysteine in living cells

Cysteine (Cys) is a vital amino acid in the body, and its abnormal expression level is associated with many diseases. In this study, a novel fluorescent probe ACHB was synthesized, showing high selectivity, anti-interference ability and achieving accurate detection of cysteine. Different from most previous off-on probes, ACHB showed an on-off fluorescence response to Cys. Acrylic ester was used as a recognizer while green fluorescence protein (GFP) chromophore derivative 4-hydroxybenzylidene-imidazolinone (HBI) was used as the fluorophore. The addition of Cys leads to the hydrolysis of the red-emitting probe (613 nm), releasing a precursor with a lower fluorescent signal and showing an on-off spectral signal, which was ideal for obtaining sensitive detection with high specificity. Furthermore, the probe was successfully applied for simultaneous determination of cysteine (Cys) in living cells and biological sample (mouse serum). In conclusion, probe ACHB is a promising tool to display the intracellular cysteine concentration level, providing a good visualization method for clinical diagnosis and scientific basic research.

Antibacterial metal-phenolic nanosheets as smart carriers for the controlled release of epirubicin hydrochloride

Bacterial infections can cause serious complications in cancer treatment and have been proven to weaken therapeutic benefits. Recently, antibacterial nanomaterials that serve as carriers for anticancer drug delivery have been attracting extensive interest due to their combined antimicrobial and anticancer activities. In this study, antibacterial metal-phenolic nanosheets (Cu-TA) were successfully prepared via the self-assembly of the metal-phenolic coordination complexes formed between copper ions and tannic acid, and the structure, morphology, and formation mechanism of Cu-TA nanosheets were explored. The antibacterial activity of Cu-TA nanosheets against both Gram-positive and Gram-negative bacteria was detected using the minimum inhibitory concentration (MIC), zone of inhibition and plate counting methods. The MIC values of both bacterial strains were about 0.4 mg mL^-1, and the killing rates of Cu-TA samples were close to 100% at the concentration of 2 and 0.2 mg mL^-1 after 12-hour incubation. Epirubicin hydrochloride (EPI) molecules were successfully loaded on the porous Cu-TA nanosheets mainly through the formation of the Cu-EPI chelate complex and strong electrostatic interactions. The Cu-EPI complex and Cu-TA nanosheets could be disassembled under acidic conditions or in the presence of high levels of glutathione (GSH) after uptake by cancer cells, which triggered the unique pH and GSH-responsive controlled release behaviors of EPI and copper ions. The MTT assay results revealed that the presence of bacteria in Hep G2 cells can greatly impair the cell death rate induced by free EPI, but the resultant EPI-loaded Cu-TA nanosheets can significantly enhance cell death both in the presence and absence of bacteria.

The ability of inflammatory markers to recognize infection in cancer patients with fever at admission

Infection is one of the main causes of death in cancer patients. Accurate identification of fever caused by infection could avoid unnecessary antibiotic treatment and hospitalization. This study evaluated the diagnostic value of procalcitonin (PCT), C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-10 (IL-10), and other commonly used inflammatory markers in suspected infected adult cancer patients with fever, for better use of antibiotics. This research retrospective analyzed the clinical data of 102 adult cancer patients with fever and compared the serum levels of commonly used inflammatory markers for different fever reasons. Receiver-operating characteristic (ROC) curve and logistic regression analyses were performed. In adult cancer patients with fever, the serum PCT, CRP, IL-6, and IL-10 levels of infected patients were significantly higher than uninfected patients (median 1.19 ng/ml vs 0.14 ng/ml, 93.11 mg/l vs 56.55 mg/l, 123.74 pg/ml vs 47.35 pg/ml, 8.74 pg/ml vs 3.22 pg/ml; Mann-Whitney p = 0.000, p = 0.009, p = 0.004, p = 0.000, respectively). The ROC area under the curve(AUC) was 0.769 (95% confidence interval (CI) 0.681-0.857; p = 0.000) for PCT, 0.664 (95% CI 0.554-0.775; p = 0.009) for CRP, 0.681(95% CI 0.576-0.785; p = 0.004) for IL-6, and 0.731(95% CI 0.627-0.834; p = 0.000) for IL-10. PCT had specificity of 96.67% and positive predictive value (PPV) of 97.6%, when the cut-off value is set as 0.69 ng/ml. The serum IL-6 and IL-10 levels also had significant differences between the infected and uninfected cancer patients with advanced disease (median 128.92 pg/ml vs 36.40 pg/ml, 8.05 pg/ml vs 2.92 pg/ml; Mann-Whitney p = 0.003, p = 0.001, respectively). For the patients with neutropenia, IL-6 and IL-10 had higher AUC of 0.811 and 0.928, respectively. With a cut-off of 9.10 pg/ml, IL-10 had the highest sensitivity 83.33% and specificity 100%. In adult cancer patients, PCT had the best performance compared to CRP, IL-6, and IL-10 in differentiating infected from uninfected causes of fever, with high specificity and PPV. IL-6 and IL-10 might be useful in cancer patients with severe bloodstream infections and advanced disease. However, for patients with neutropenia, IL-10 might be more valuable than PCT in diagnosing infection.

Predictive Factors for Gram-negative Versus Gram-positive Bloodstream Infections in Children With Cancer

BACKGROUND

Identifying potential predictive factors for the type of bacteremia (Gram-negative vs. Gram-positive) in children with cancer would be crucial for the timely selection of the appropriate empiric antibiotic treatment.

MATERIALS AND METHODS

Demographic, clinical, and laboratory characteristics of children with cancer and a bacterial bloodstream infection (BSI) (February 1, 2011 to February 28, 2018) in a tertiary pediatric oncology department were retrospectively examined and were correlated with the type of isolated bacteria.

RESULTS

Among 224 monomicrobial bacterial BSI episodes, Gram-negative and Gram-positive bacteria were isolated in 110 and 114 episodes, respectively. Gram-negative bacteria were isolated significantly more frequently in girls (Gram-negative/Gram-positive ratio 1.7:1) versus boys (Gram-negative/Gram-positive ratio 0.72:1), P=0.002, in patients with previous BSI episodes (1.4:1) versus those without (0.8:1), P=0.042, and in children with hematologic malignancy (1.3:1) versus those who suffered from solid tumors (0.52:1), P=0.003. Gram-negative BSI episodes were more frequently correlated with a lower count of leukocytes, P=0.009, neutrophils, P=0.009 and platelets, P=0.002, but with significantly higher C-reactive protein (CRP) levels, P=0.049. Female sex, hematologic malignancy, and higher CRP levels remained independent risk factors for Gram-negative BSI in the multivariate analysis. Among neutropenic patients, boys with solid tumors and a recent central venous catheter placement appear to be at increased risk for Gram-positive BSI in the multivariate analysis.

CONCLUSIONS

Although Gram-negative and Gram-positive BSIs are close to balance in children with cancer, Gram-negative bacteria are more likely to be isolated in girls, children with hematologic malignancies and those with higher CRP level at admission. In contrast, neutropenic boys with solid tumors and a recently placed central venous catheter may be at increased risk for Gram-positive BSI indicating probably the need for initially adding antibiotics targeting Gram-positive bacteria.

Microbiology Assessments in Critically Ill Patients

The prevalence of suspected or proven infections in critically ill patients is high, with a substantial attributable risk to in-hospital mortality. Coordinated guidance and interventions to improve the appropriate microbiological assessment for diagnostic and therapeutic decisions are therefore pivotal. Conventional microbiology follows the paradigm of "best practice" of specimen selection and collection, governed by laboratory processing and standard operating procedures, and informed by the latest developments and trends. In this regard, the preanalytical phase of a microbiological diagnosis is crucial since inadequate sampling may result in the incorrect diagnosis and inappropriate management. In addition, the isolation and detection of contaminants interfere with multiple intensive care unit (ICU) processes, which confound the therapeutic approach to critically ill patients. To facilitate bedside enablement, the microbiology laboratory should provide expedited feedback, reporting, and interpretation of results. Compared with conventional microbiology, novel rapid and panel-based diagnostic strategies have the clear advantages of a rapid turnaround time, the detection of many microorganisms including antimicrobial resistant determinants and thus promise substantial improvements in health care. However, robust data on the clinical evaluation of rapid diagnostic tests in presumed sepsis, sepsis and shock are extremely limited and more rigorous intervention studies, focusing on direct benefits for critically ill patients, are pivotal before widespread adoption of their use through the continuum of ICU stay. Advocating the use of these diagnostics without firmly establishing which patients would benefit most, how to interpret the results, and how to treat according to the results obtained, could in fact be counterproductive with regards to diagnostic "best practice" and antimicrobial stewardship. Thus, for the present, they may supplement but not yet supplant conventional microbiological assessments.

Herpesviridae in critically ill hematology patients: HHV-6 is associated with worse clinical outcome

PURPOSE

Although viral infections are frequent among patients with hematological malignancies (HM), data about herpesviridae in critically ill hematology patients are scarce. We aimed at determining the impact of herpesviridae reactivation/infection in this population.

MATERIAL AND METHODS

We performed a single center retrospective study including all consecutive adult hematology patients admitted to our comprehensive cancer center ICU on a 6-year period. Clinical characteristics, microbiological findings, especially virus detection and outcome were recorded.

RESULTS

Among the 364 included patients, HHV-6 was the predominant retrieved herpesviridae (66 patients, 17.9%), followed by HSV1/2 (41 patients, 11.3%), CMV (38 patients, 10.4%), EBV (24 patients, 6.6%) and VZV (3 patients). By multivariable analysis, HHV-6 reactivation was independently associated with hospital mortality (OR, 2.35; 95% CI, 1.03-5.34; P = 0.042), whereas antiviral prophylaxis during ICU stay had a protective effect (OR, 0.41; 95% CI, 0.18-0.95; P = 0.037). HHV-6 pneumonitis was independently associated with 1-year mortality (OR, 6.87; 95% CI, 1.09-43.3; P = 0.04).

CONCLUSIONS

Among critically ill hematology patients, HHV-6 reactivation and pneumonitis are independent risk factors for hospital and 1-year mortality, respectively. Impact of prevention and treatment using agents active against HHV-6 should be assessed to define a consensual diagnostic and therapeutic strategy.

Performance of the sōna Aspergillus Galactomannan Lateral Flow Assay in a Cancer Patient Population

The diagnosis of invasive aspergillosis can be challenging in cancer patients. Herein, the analytical and clinical performance of the sōna Aspergillus galactomannan lateral flow assay (GM LFA) was evaluated and its performance compared to that of the Bio-Rad galactomannan enzyme immunoassay (GM EIA). Serum and bronchoalveolar lavage (BAL) fluid samples received for GM EIA testing between March and August 2019 were included. Positive and negative percent agreement (PPA and NPA) were calculated for the GM LFA compared to the GM EIA. Discrepant analysis was performed by review of the patient's medical records assessing for any evidence of a fungal infection. Five hundred thirty-three samples (85 BAL samples and 448 serum samples) from 379 patients were included in the study. The overall PPA and NPA were 100% (95% confidence interval [CI], 72.2 to 100%) and 97.5% (95% CI, 95.5 to 98.4%), respectively. Fourteen of 24 samples were positive by LFA only. The sensitivity of the GM LFA for proven and probable invasive aspergillosis (IA) was 100% (95% CI, 51.0 to 100%) and 87.5% (95% CI, 55.9 to 99.4%), with a specificity of 95.5% (95% CI, 92.3 to 97.2%) and 96.2% (95% CI, 93.4 to 97.7%), respectively. The sensitivity of the GM EIA for proven and probable IA was 25% (95% CI, 1.28 to 69.9%) and 62.5% (95% CI, 30.6 to 86.3%), with a specificity of 98.2% (95% CI, 96.2 to 99.1%) and 99.2% (95% CI, 97.7 to 99.8%), respectively. The Aspergillus GM LFA outperformed the Aspergillus GM EIA for the detection of the galactomannan antigen in our patient population. The simplicity and rapid time to results makes the Aspergillus GM LFA easy to implement in a wide range of laboratory settings.

Sepsis in patients with haematological versus solid cancer: a retrospective cohort study

OBJECTIVES

This study aims to examine the outcome of haematological and patients with solid cancer presenting with sepsis to the emergency department (ED).

DESIGN

Single-centred, retrospective cohort study. Setting conducted at an academic emergency department of a tertiary hospital.

PARTICIPANTS

All patients >18 years of age admitted with sepsis were included.

INTERVENTIONS

Patients were stratified into two groups: haematological and solid malignancy.

PRIMARY AND SECONDARY OUTCOME

The primary outcome of the study was in-hospital mortality. Secondary outcomes included intensive care unit (ICU) mortality, ICU and hospital lengths of stay and mechanical ventilation duration.

RESULTS

442 sepsis cancer patients were included in the study, of which 305 patients (69%) had solid tumours and 137 patients (31%) had a haematological malignancy. The mean age at presentation was 67.92 (±13.32) and 55.37 (±20.85) (p<0.001) for solid and liquid tumours, respectively. Among patients with solid malignancies, lung cancer was the most common source (15.6%). As for the laboratory workup, septic solid cancer patients were found to have a higher white blood count (12 576.90 vs 9137.23; p=0.026). During their hospital stay, a total of 158 (51.8%) patients with a solid malignancy died compared with 57 (41.6%) patients with a haematological malignancy (p=0.047). There was no statistically significant association between cancer type and hospital mortality (OR 1.15 for liquid cancer p 0.58). There was also no statistically significant difference regarding intravenous fluid administration, vasopressor use, steroid use or intubation.

CONCLUSION

Solid tumour patients with sepsis or septic shock are at the same risk of mortality as patients with haematological tumours. However, haematological malignancy patients admitted with sepsis or septic shock have higher rates of bacteraemia.

Antibacterial nanosystems for cancer therapy

Bacteria and cancer cells share a unique symbiotic relationship in the process of cancer development and treatment. It has been shown that certain bacteria can mediate cancer and thrive inside cancerous tissues. Moreover, during cancer treatment, microbial infections have been shown to impair the therapeutic efficacy and lead to serious complications. In the past decades, the application of antibiotics has achieved great success in fighting numerous bacteria but the administration route, low localization effects and related drug resistance limit the further utilization of antibiotics. Recently, advances in nanotechnology have made a significant impact in the medical field, which enhance the drug solubility and can target lesion sites, and some nanomaterials can even be applied as the therapeutic agent itself. In this review, we introduce anti-bacterial nanosystems for cancer therapy in the aspects of spontaneous and triggered anti-bacterial action, and our notions, as well as proposed research directions for the further development of this field, are discussed.

Epidemiology and clinical characteristics of viral infections in hospitalized children and adolescents with cancer in Lebanon

Background

Viral infections in children and adolescents with malignancy are commonly encountered and have a significant impact on morbidity and mortality. Studies and epidemiological data regarding viral infections in children with cancer in developing countries are lacking. This retrospective cohort study aims to assess the burden of viral infections in children and adolescents with cancer, by assessing prevalence, risk factors, as well as morbidity and mortality of common viruses over a period of 8 years.

Methods and findings

Medical records of cancer patients treated at the Children Cancer Center of Lebanon were reviewed and 155 participants under the age of 21 were identified with at least one documented viral infection during the period from July 2009 to November 2017. This subset included 136 participants with active malignancy and 19 participants with a history of cancer who underwent hematopoietic stem cell transplantation [HSCT] and were in remission; the latter group was analyzed separately. Information regarding participant characteristics, hospital course, and complications were obtained. Associations between viral infections and certain factors were assessed. In the cohort, 64% were male, 81% were Lebanese. In participants with active malignancy, 90% received chemotherapy in the 6 months preceding the viral infection episode, 11% received radiotherapy. 51% of participants were neutropenic at the time of viral detection, and 77% were lymphopenic. 17% experienced a bacterial co-infection, and 3 experienced a viral co-infection. Among 162 viral infection episodes, clinically diagnosed skin infections, mainly herpes simplex virus type 1 and varicella-zoster virus, were the most common [44% of cases]. These were followed by laboratory-proven systemic herpes infections: cytomegalovirus [14%] and Epstein-Barr virus [6%]. Respiratory viruses: influenza and respiratory syncytial virus, accounted for 9% and 4%, respectively, whereas rotavirus represented 11% and BK virus represented 3% of cases. Acute lymphocytic leukemia was the most prevalent neoplasia [57%]. Fever was the most common presenting symptom [55%] and febrile neutropenia was the reason for admission in 24% of cases. The mean length of stay was significantly longer in participants with cytomegalovirus infections and significantly lower in rotavirus infection. Admission to the ICU occurred in 9%, complications in 8%, and mortality in 5%. Participants with viral infections post-HSCT were noted to have a significantly longer length of hospital stay compared to non-HSCT participants, with no other significant differences in clinical course and outcome. The study was limited by its retrospective nature and by the late introduction and underuse of multiplex PCR panels, which may have led to underdiagnosis of viral infections.

Conclusions

Viral infections were prevalent in our sample of cancer patients and may have contributed to morbidity and mortality. Newly available viral diagnostics are likely to vastly increase the number and scope of detectable viral infections in this population. Prospective studies using multiplex PCR technology with systematic testing of patients will be more helpful in defining the burden of viral infections. Furthermore, efforts at antimicrobial stewardship would benefit from the identification of viral causes of infection and limit the unnecessary use of antibiotics in the pediatric cancer population.

Viruses and atypical bacteria in the respiratory tract of immunocompromised and immunocompetent patients with airway infection

Respiratory tract infections (RTI) can take a serious course under immunosuppression. Data on the impact of the underlying pathogens are still controversial. Samples from the upper (n = 322) and lower RT (n = 169) were collected from 136 children and 355 adults; 225 among them have been immunocompromised patients. Exclusion criteria were presence of relevant cultivable microorganisms, C-reactive protein > 20 mg/dl, or procalcitonin > 2.0 ng/ml. Samples were tested by PCR for the presence of herpesviruses (HSV-1/-2; VZV; CMV; HHV6; EBV), adenoviruses, bocaviruses, entero-/rhinoviruses (HRV), parechoviruses, coronaviruses, influenza viruses (IV), parainfluenza viruses as well as for pneumoviruses (HMPV and RSV), and atypical bacteria (Mycoplasma pneumoniae, M.p.; Chlamydia pneumoniae, C.p.). Viral/bacterial genome equivalents were detected in more than two-thirds of specimens. Under immunosuppression, herpesviruses (EBV 30.9%/14.6%, p < 0.001; CMV 19.6%/7.9%, p < 0.001; HSV-1: 14.2%/7.1%, p = 0.012) were frequently observed, mainly through their reactivation in adults. Immunocompromised adults tended to present a higher RSV prevalence (6.4%/2.4%, p = 0.078). Immunocompetent patients were more frequently tested positive for IV (15.0%/5.8%, p = 0.001) and M.p. (6.4%/0.4%, p < 0.001), probably biased due to the influenza pandemic of 2009 and an M.p. epidemic in 2011. About 41.8% of samples were positive for a single pathogen, and among them EBV (19.9%) was most prevalent followed by HRV (18.2%) and IV (16.6%). HSV-2 and C.p. were not found. Marked seasonal effects were observed for HRV, IV, and RSV. Differences in pathogen prevalence were demonstrated between immunocompetent and immunocompromised patients. The exact contribution of some herpesviruses to the development of RTI remains unclear.

Burden and clinical outcomes of hospital-coded infections in patients with cancer: an 11-year longitudinal cohort study at an Australian cancer centre

PURPOSE

Patients with cancer are at increased risk for infection, but the relative morbidity and mortality of all infections is not well understood. The objectives of this study were to determine the prevalence, incidence, time-trends and risk of mortality of infections associated with hospital admissions in patients with haematological- and solid-tumour malignancies over 11 years.

METHODS

A retrospective, longitudinal cohort study of inpatient admissions between 1 January 2007 and 31 December 2017 at the Peter MacCallum Cancer Centre was conducted using administratively coded and patient demographics data. Descriptive analyses, autoregressive integrated moving average, Kaplan-Meier and Cox regression modelling were applied.

RESULTS

Of 45,116 inpatient hospitalisations consisting of 3033 haematological malignancy (HM), 18,372 solid tumour neoplasm (STN) patients and 953 autologous haematopoietic stem cell transplantation recipients, 67%, 29% and 88% were coded with ≥ 1 infection, respectively. Gastrointestinal tract and bloodstream infections were observed with the highest incidence, and bloodstream infection rates increased significantly over time in both HM- and STN-cohorts. Inpatient length of stay was significantly higher in exposed patients with coded infection compared to unexposed in HM- and STN-cohorts (22 versus 4 days [p < 0.001] and 15 versus 4 days [p < 0.001], respectively). Risk of in-hospital mortality was higher in exposed than unexposed patients in the STN-cohort (adjusted hazard ratio [aHR] 1.61 [95% CI 1.41-1.83]; p < 0.001)) and HM-cohort (aHR 1.30 [95% CI 0.90-1.90]; p = 0.166).

CONCLUSION

Infection burden among cancer patients is substantial and findings reflect the need for targeted surveillance in high-risk patient groups (e.g. haematological malignancy), in whom enhanced monitoring may be required to support infection prevention strategies.

Multiple Drug Resistance Patterns in Various Phylogenetic Groups of Hospital-Acquired Uropathogenic E. coli Isolated from Cancer Patients

Cancer patients are more susceptible to several bacterial infections, particularly urinary tract infections caused by uropathogenic E. coli (UPEC). The objective of this work was detection and the phylogenetic characterization of hospital-acquired isolates of uropathogenic E. coli in cancer patients and the determination of its relation with antibiotic resistance. A total of 110 uropathogenic E. coli responsible for hospital-acquired urinary tract infections in cancer patients were included in this study. A triplex PCR was employed to segregate different isolates into four different phylogenetic groups (A, B1, B2 and D). Drug resistance was evaluated by the disc diffusion method. All of the isolates were multiple drug-resistant (MDR) and 38.18% of all UPEC isolates were extended-spectrum beta-lactamase (ESBL) producers from which 52% were positive for the blaCTX-M gene, 40% for the blaTEM gene, and 17% for the blaSHVgene. Among 42 ESBL-producing uropathogenic E. coli isolates, the majority belonged to phylogenetic group B2 (43%), followed by group D (36%), group A (19%) and group B1 (2%). Our results have shown the emergence of MDR isolates among uropathogenic E. coli with the dominance of phylogenetic group B2. Groups A and B1 were relatively less common. The most effective drug in all phylogenetic groups was imipenem.

Pattern of Antimicrobial Sensitivity in Microbiologically Documented Infections in Neutropenic Patients with Haematological Malignancies: A single Center Study

Febrile neutropenia is a medical emergency that complicates the clinical course and treatment of haematological malignancies, significantly enhancing the financial burden and worsening the overall outcome. This study was carried out to evaluate the efficacy of institution's current first-line antibiotic regimen for febrile neutropenia in view of recent spectrum of institution's local flora and its susceptibility pattern. 163 episodes of microbiologically documented infections in 110 adult patients were studied over a period of 1 year. Of 110 patients, 61 patients were male. The mean age of the patient population, mean absolute neutrophil count and temperature as documented were 30.1 years (SD ± 16.8), 450 cells/ul, and 101.9 °C respectively. Gram-negative and gram-positive organisms accounted for 79% and 21% of the febrile neutropenic infections respectively. E. coli and Staphylococcus aureus were the most common gram positive and gram negative pathogens respectively. A susceptibility pattern of > 60% was documented for all the gram negative pathogen's associated febrile neutropenic infections for the current first-line antibiotic combination of Piperacillin/Tazobactum and Amikacin. Comparative analysis of results with the institutional data of 2015 study revealed no statistically significant difference in the resistance pattern of the organisms hence, validating the persistent use of Piperacillin/Tazobacum and Amikacin combination as a potent and efficacious therapy for febrile neutropenia patients with haematological malignancies. However, continuous surveillance remains prudent for the emerging changes in the spectrum and resistance pattern of local flora so that timely revision of empirical antibiotic regimens can save the added financial burdens and associated high morbidity and mortality.

Limited diagnostic value of a multiplexed gastrointestinal pathogen panel for the detection of adenovirus infection in an oncology patient population

BACKGROUND

Diagnosis of Adenovirus infections in transplant patients may be accomplished using either plasma or stool samples. IVD-cleared multiplexed gastrointestinal (GI) PCR panels offer an option for rapid testing of stool samples but most only target Adenovirus (HAdV) types F40/41.

OBJECTIVES

Given the potential significance of a positive adenovirus test in an immunocompromised patient, we sought to determine the frequency of type 40/41 in our patient population and the utility of a readily available multiplexed, FDA-cleared GI Panel for the detection of adenovirus infections.

STUDY DESIGN

A total of 215 specimens from immunocompromised patients mostly with hematologic malignancy or transplant recipients were evaluated including 107 plasma samples, 85 stool samples and 23 respiratory samples. Genotyping was performed successfully on 122 specimens.

RESULTS

The most common type detected in all samples including stools was Adenovirus C/2. In a subset of patients with multiple specimen types tested, similar types were detected in all samples.

CONCLUSIONS

Although Adenovirus F40/41 is the most common enteric type, Adenovirus C/2 was the most common type identified in stools and subsequently plasma samples of our patient population. Implementation of assays that have wide reactivity for most adenovirus types is essential for optimal diagnostic yield.

Detection of gastrointestinal pathogens in oncology patients by highly multiplexed molecular panels

We compared the frequency of gastrointestinal (GI) pathogen detection in an oncology patient population by two multiplexed molecular assays, the Luminex xTAG® Gastrointestinal Pathogen Panel (GPP, which identifies 14 GI pathogens) and the BioFire Gastrointestinal Panel (BFGP, which identifies 22 GI pathogens). We additionally reviewed the clinical characteristics of patients tested with both panels. A total of 200 prospectively collected and 81 archived stool samples were tested by both panels. In the prospective cohort, the GPP and BFGP identified a pathogen in 33.5% [95% confidence interval (CI): 27.3-40.35%] and 39.6% (95% CI: 33.0%-46.6%) of samples, respectively (p = 0.25). The BFGP detected significantly more pathogens than the GPP (p = 0.038), with 21.3% of samples positive for targets only detected by the BFGP. The concordance between the assays was very good at 91.1% (κ = 0.8, 95% CI: 0.7-0.9) when considering only pathogens detected by both assays. The most frequent pathogens detected were Clostridium difficile, norovirus, Campylobacter, and Salmonella species. On the archived samples, the BFGP was positive in 92.6% of samples but detected more pathogens than the GPP (86 vs. 97, p = 0.033), including both targets unique to the BFGP and targets common to both panels. A pathogen was more frequently detected in patients with hematological malignancies than solid tumors and in ambulatory patients compared to hospitalized patients, but these differences were not statistically significant. Overall, the detection rates were similar for both the GPP and the BFGP, and the latter detected more than one pathogen in additional patients. The impact of increased detection of GI pathogens by multiplexed panels on the clinical care of oncology patients will require further investigation.