Bloodstream Bacterial Infection in Neutropenic Acute Leukemia Patients

Objective: The rapid detection of blood stream infection has the potential to not only improve patient outcomes due to quicker administration of appro-priate antibiotics but also improve antibiotic stewardship by reducing patient exposures to ineffective or unnecessary broad-spectrum antibiotics. Methods: In this study blood samples from acute leukemia neutropenic patients (sam-ples under study) and non neutropenic patients (control) were tested using cultural and non-cultural based techniques via blood culture, C-reactive protein (CRP), Erythrocyte sedimentation rate (ESR) and Molecular techniques (bacterial 16S rDNA analysis). Results: About 22% & 15% were shown positive in blood culturing; 94% & 85% were positive for CRP; 86% and 75% were presented by elevation in ESR rate for the first hour; 94% and 80% were presented by elevation in ESR rate for second hour. Treatment response of the positive cases by blood culture only was found to be 72.7% and 100% not in remission for samples under study and control respectively. In cases under study there is statistically significant correlation between culture growth sensitivity and PCR technique with P value < 0.005.


Introduction
Bloodstream infection (BSI) in neutropenic patients, is a severe complication and is associated with increased mortality. BSI is routinely diagnosed with blood culture, which detects only culturable pathogens [1]. BSI is treated with broad-spectrum of empirical antimicrobials, due to the lack of specificity or resistance mechanisms systemic infections. The antimicrobials are often not efficient against the invading microbes [2] [3] and [4], and its treatment might be inappropriate due to the lack of coverage of the underlying pathogen(s), or the causative pathogens antimicrobial resistance [5]. Although Blood culture only detects culturable pathogens and represents a narrow spectrum of the microbes present in a sample, it requires relatively large volumes of samples [6]. About 75% from febrile neutropenia, and 50% of blood cultures from septic shock are positive [1] [7] and [8]. In hemato-logical malignancies the most commonly detected pathogens are bacteria, also fungal and viral infections represent in major complications [1] [6] and [9].
In patients who have bloodstream infections, the viable microorganisms are present in blood [10]. In peripheral blood the density of microorganisms in adults may be as low as ten microorganisms per milliliter and about 100 microorganisms per milliliter in children [11]. In principle, the sensitivity of blood cultures is enough to detect these low amounts of microorganisms; however, the density varies during the course of disease, and therefore the blood culture diagnostics will not always yield positive results; therefore recommendation for culturing sufficient quantities of blood is in patients with suspected sepsis [12].
Blood cultures have several advantages. First, they have been in use for more than 100 years and are well integrated in the clinical workflow and clinical guidelines. Second, semi-automated culture systems have greatly simplified handling in the microbiological laboratory which results in a short hands-on time.
Third, a wide range of bacterial and fungal pathogens can be isolated and identified [13]. Furthermore, isolation of the pathogen is a prerequisite to phenotypic susceptibility testing which enables clinicians to initiate targeted antimicrobial therapy. However, there are limitations in blood culture diagnostics: detection is limited to pathogens that have the ability to grow in blood cultures. Some microorganisms, such as Legionella spp., Bartonella spp., and Aspergillus spp., grow poorly in blood culture medium. Furthermore, antimicrobials may cause growth inhibition and relevant pathogens may thus go undetected, after the initiation of antimicrobial therapy [14] [15]. Most importantly, many clinicians feel that results are available too late to guide therapy because of blood culture diagnostics requires some time until results are available [16].
Biomarkers, such as C-reactive protein or procalcitonin, aid in the diagnosis of sepsis and they are usually available before microbiological test results. Unfortunately, currently available biomarkers have a low sensitivity and specificity [17] [18] and [19].
Molecular techniques have been developed with the aim to carryout sensitivity progression and to detect bloodstream infection earlier [20] [21].
In pneumococcal pneumonia, blood cultures often remain negative and polymerase chain reaction (PCR)-based detection of Streptococcus pneumoniae in patients with a clinical suspicion for pneumonia has been shown to be more sensitive than blood cultures in clinical studies [22] [23].

The Clinical Data at Presentation
Clinical data including age, sex, and presenting clinical features (lymph node enlargement, Splenomegaly, fever and infection, renal problems, liver problems, and Anemia).

Material and Methods
Blood of (10 -15) ml was collected by either a venous or arterial draw at the same time as the routine clinical blood samples using the same needle stick.

Complete Blood Count
Small aliquots 2ml blood was inoculated to K-EDTA, and performed by using SN (60SPN0694) HORIBA & manual differential count.

Culture Growth and Sensitivity
Blood of 3 -5 ml inoculated in to blood culture media, Small aliquots was taken for culturing on solid media and for gram stain, identification and determination of sensitivity to antibiotic were performed by using VITEK ® 2 System (BIOMERIEUX) SN (510774-3EN1) USA.

Creactive Protein (CRP)
Serum samples were taken and performed by bioscien CRP latex kit Qualitative and Semi-Qualitative test.

Erythrocyte Sedimentation Rate (ESR)
Blood of 1.6 ml was inoculated in Tube containing 0.4 ml of sodium citrate solution. ESR is carried out by using LENA S.N (002164) Barcelona Spain.   Table 2).

Results and Discussion
The overall proportion of infected cases positive by blood culture was found  Table 4).
The overall proportion of patients after treatment: for neutropenic acute leukemia patients, 27 patients (54%) were in remission while 23 patients (46%) were not. For non neutropenic acute leukemia patients, 11 patients (55%) were in remission while 9 patients (45%) were not.
Concerning to age, there is no significant correlation between neutropenic   According to type of AL, was found to be 4 patients (      Concerning to identification of blood stream bacterial species using PCR technique, we found that there is statistically significant correlation between culture growth sensitivity and PCR with P value < 0.005, this is mainly due to about (96%) opositive samples by blood culture were also positive by PCR, indeed 2 cases out of 50 were positive by PCR but negative by blood culture.
The overall of isolated bacteria from neutropenic acute leukemia patients according to PCR test were staphylococcus aureus, Sphingomonas paucimobilis, Escherichia coli and klebsiella pneumonia.
The infection in neutropenic acute leukemia patients is more incident and associated with more virulence and resistance bacteria than non neutropenic acute leukemia patients.
Not surprisingly, this fundamental principle was associated with high mortality rate among all patients, because that administration of inadequate or inappropriate antimicrobial treatment was also associated with increased hospital mortality.
In the agreement of our study [24] reported that resistance to common antimicrobial agents is being encountered increasingly at most hospitals, in part because of heavy use of antibiotics.
Similarly [25] reported that prophylactic antibiotics have demonstrated some efficacy in reducing the risk of febrile episodes in neutropenic patients with cancer; however, these agents have been associated with additional toxicity and the emergence of antibiotic-resistant bacteria.

Conclusions
The infection in neutropenic acute leukemia patients is more prevalent and associated with more virulence and resistance of gram positive bacteria than non neutropenic acute leukemia patients. The bacterial species associated with neutropenic acute leukemia patients are more resistant to antibiotic than those associated with non neutropenic acute leukemia patients.
Concerning treatment response of the cases positive for bacterial growth, the remission rate was less in neutropenic acute leukemia than non neutropenic acute leukemia patients. So the earlier detection of the infection the faster prognosis of the disease.