Detection of Bloodstream Pathogens in Hematological Malignancies

Study Overview
=================
Brief Summary
-----------------
To identify the common bacterial and fungal species causing fungemia and bacteremia in hematological malignancies. To identify sensitivity pattern for causative microbes. Compare culture on ordinary media with Vitek2 (automated microbial identification system) and multiplex polymerase chain reaction (PCR )

Detailed Description
-----------------
Sepsis is a global health problem and an estimated 17 million cases of sepsis occur each year in the world .The early initiation of appropriate antibiotic therapy is determinant for the prognosis and survival of patients with bloodstream infections . Infections in patients suffering from hematological malignancies are a frequent problem, leading to higher mortality and morbidity, increased costs of health care and prolonged duration of hospitalization. Common among these infections are those involving the bloodstream. In febrile neutropenic patients, the attack rate of bloodstream infection was reported to be between 11 and 38% . Hematological malignancies by themselves or by their therapeutic strategies, put patients at risk for infections. Wide use of antibiotics and prophylactic agents in such patients has led to the development of resistance. The general term fungemia describes the presence of a fungal species in the blood while term bacteremia describes the presence of bacterial species in the blood A positive culture may indicate a widespread infection or commonly, the infection of an intravenous catheter .Fungal microbes are abundant in nature and are frequent colonizers on human mucosal surfaces. However, under conditions of impaired immune responses or a break in host barriers, fungi are able to invade normally sterile areas of the human body, where they can cause severe infections that are difficult to recognize and treat and are often ultimately lethal .Indeed, recent epidemiological data show that invasive fungal infections (IFIs) are frequently encountered in clinical practice, with the most common offenders, being Candida spp. and Aspergillus spp. In order to effectively eliminate these infections, early diagnosis and species identification are of paramount importance. Traditional diagnostic methods such as blood culture is still considered the gold standard .Indeed ,novel molecular and non molecular techniques have been developed and currently under clinical evaluation . The VITEK 2 is an automated microbial identification system that utilizing growth-based technology. With its colorimetric reagent cards, the VITEK 2 offers a state of the art technology platform for phenotypic identification methods. The application of the multiplex polymerase chain reaction PCR method in the diagnosis of bloodstream infections is designed to reduce the time for identification of the microorganisms grown from the positive samples to 24-48 hours, as pathogens are identified directly from a positive blood sample

Official Title
-----------------
Detection of Bloodstream Pathogens in Hematological Malignancies

Conditions
-----------------
Bloodstream Infection

Intervention / Treatment
-----------------
* Diagnostic Test: blood culture
* Other: Anti fungal susceptibility testing or antibiotic susceptibility testing
* Other: phenotypic identification methods of the isolated organism by Vitek2 (BioMerieux,France)
* Other: Identification of the isolated organism by multiplex PCR


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: hematological malignancy patients on chemotherapy associated with fever Exclusion Criteria: Age below 18 years old

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| blood culture positive<br>hematological malignancy patients with positive blood culture | Diagnostic Test: blood culture<br>* During the febrile episode, two blood samples per patient will draw from two separate sites including central venous catheter if present and directly injected to Bact/Alert® bottles and incubated in Bact/ALERT system instrument (bioMérieux Diagnostics, Lyon, France). A-Identification of microorganisms including: Isolation of microorganisms: Blood culture samples with positive signals will be cultured on blood agar, chocolate agar , MacConkeys agar and Sabouraud dextrose agar (SDA) plates. B-Identification of the bacterial organism Pure colonies of isolated microorganisms were identified by: Morphology on agar,Gram stain film was made from the growth to identify morphology of the organism ,Biochemical tests C-For fungi isolate the following will perform: Microscopic examination of Lactophenol cotton blue (LCB) wet mounts. Culture on Brilliance Candida differential agar<br>Other: Anti fungal susceptibility testing or antibiotic susceptibility testing<br>* isolation of microbes from positive blood culture and anti fungal susceptibility testing or antibiotic susceptibility testing according to isolated microbes by disc diffusion method and Vitek2<br>* Other names: antimicrobial susceptibility testing;Other: phenotypic identification methods of the isolated organism by Vitek2 (BioMerieux,France)<br>* The VITEK 2 is an automated microbial identification system that utilizing growth-based technology. With its colorimetric reagent cards, the VITEK 2 offers a state of the art technology platform for phenotypic identification methods.<br>* Other names: Vitek2 (BioMerieux,France);Other: Identification of the isolated organism by multiplex PCR<br>* FilmArray blood culture identification (BCID) is automated multiplex PCR assay, the FilmArray blood culture identification which directly identifies common pathogens, including 7 genera/ species of Gram-positive bacteria, 10 genera/species of Gram-negative bacteria, and 5 species of Candida (as well as 3 resistance determinants) in the positive blood culture bottles. The assay requires about 2 min of hands-on sample processing time and 1 h of instrument time (which includes DNA isolation, amplification, and detection).<br>* Other names: multiplex PCR;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| identify pathogens in positive blood culture in hematological malignancies patients | Examine blood culture to diagnose different species of pathogens including bacteria and fungi responsible for bloodstream infection in hematological malignancies patients. | 1 year | 
| Antimicrobial susceptibility testing and drug resistance | performance of antimicrobial susceptibility testing (anti fungal susceptibility testing or antibiotic susceptibility testing )of significant bacterial isolates. The goals of testing are to detect possible drug resistance in common pathogens and to assure susceptibility to drugs of choice for particular infections. | 1 year | 
| prevalence of bloodstream infection in hematological malignancy patients | prevalence of both bacteremia and fungemia in hematological malignancies using blood culture | 1 year | 
| Time from blood collection to pathogen identification | The hypothesis is that faster identification will lead to faster action. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| In-hospital mortality. | Faster treatment is associated with reduced mortality | 1 year | 
| Rapid diagnosis of bloodstream infections | Compare different methods for rapid identification of blood culture positive results including Vitek2 (BioMerieux,France) and multiplex PCR | 1 year |