Administrative Information

المعلومات الادارية

عنوان المشروع- Project Title

بلغة اجنبية:

Comparison of blood cultures and 16S rRNA gene sequencing for diagnosis of bacteremia in febrile neutropenic patients

باللغة العربية:

غير متوفر

الباحث الرئيسي Principal Investigator -

الاسم Name	المؤسسة Institution	الوظيفية Post	العنوان Address	العنوان الالكتروني e-mail	رقم الهاتف Telephone
S. Kanj	AUB	Associte Professor, Head Division of Infectious Diseases	AUBMC, Department of Internal Medicine	sk11@aub.edu.lb	01-350000 extension 5353

الباحثون المشاركون Co-Workers -

الاسم Name	المؤسسة Institution	العنوان الالكتروني e-mail
M. Kattar	AUB	mk33@aub.edu.lb
G. Araj	AUB	garaj@aub.edu.lb

المدة التعاقدية للمشروع Duration -: (2 years)

Scientific Information

المعلومات العلميّة

الهدف- Objectives

Investigate whether universal bacterial PCR amplification combined with DNA sequencing can improve the diagnosis of infections in febrile neutropenic patients. A parallel clinical observational study was done to evaluate the most current epidemiological trends among patients with neutropenic fever at AUBMC.

ألانجازات المحققة Achievements -

The 16S rRNA gene sequencing technique was developed at our institution and is currently being used for identification of culture isolates that are difficult to identify by conventional biochemical methods.

The clinical study reulted in a better understanding of the epidemiology of neutropenic fever at AUBMC

آفاق البحث Perspectives -

This technique needs further refinements to be made in order to enable identification of bacteria directly from clinical specimens. The latter is due to the ubiquitous nature of bacterial DNA which makes it difficult to distinguish bacterial contamination from true infection.Similar data were obtained by other groups of investigators while the study was under way.

Although no publications have resulted yet from the molecular part of this project, the technique that was developed and adopted, in part with the supplied funds is currently being used to investigate the epidemiology of atypical mycobacterial infections (MOTT) in Lebanon. We have already identified >100 consecutive MOTT isolates. This work will be the subject of future presentations and a publication.

المنشورات والمساهمات في المؤتمرات- Publications & Communications

Profile of Infections in febrile neutropenic patients at a teriary care center in lebanon: a view of the past decade. The manuscipt is In Press in International Journal of Infectious Diseases, 2007

• Bloodstream infections in febrile neutropenic patients at a tertiary care center in Lebanon: a view of the past decade

Zeina A. Kanafani a, Ghenwa K. Dakdouki b, Khalil I. El-Chammas c,

Shaker Eid d, George F. Araj e, Souha S. Kanj f,

موجز باللغة العربية عن نتائج البحث Abstract in Arabic

We have found that universal bacterial amplification from clinical specimens is problematic due to the ubiquitous nature of bacterial DNA. Indeed, bacterial DNA is present in tubes collected from patients for testing and in reagents used for PCR. This has made it difficult to detect minute amounts of bacterial DNA causing infection from clinical specimens and to distinguish experimental bacterial contamination from true infection. Such problems could be circumvented by attempting to detect common bacteria causing infections including common gram-negative and gram-positive bacteria e.g. using real-time PCR assays with specific primers and probes, and fungi e.g. Aspergillus species. Such assays could be developed using “microbiology grade reagents” that have recently become available on the market. Such reagents are certified to be free from bacterial and fungal DNA.

In the clinical study we found that febrile neutropenic patients continue to have a predominance of gram negative infections. We included 177 episodes of neutropenic fever. The most common underlying malignancy was lymphoma (42.4%). Gastrointestinal and abdominal infections were predominant (31.6%) and 23.7% of cases represented fever of unknown origin. Gram-negative organisms were responsible for 78.8% (26/33) of bloodstream infections compared to 33.3% (11/33) with Gram-positive organisms. The in-hospital mortality rate in this study (12.1%) was considerably lower than in previous years.

Conclusions: Gram-negative organisms are persistently predominant in our center. In a developing country like Lebanon with limited resources, lower mortality rates commensurate with worldwide reports were successfully achieved in this high-risk patient population. Protocols and guidelines should be adapted to the characteristics of individual institutions to ensure delivery of appropriate care to febrile neutropenic patients.