Articles 2020

The Use of Biomarkers in the Diagnosis and Management of Sepsis

Janice Conway-Klaassen, Patricia Tille, Hassan Aziz

Int. J. Bio. Lab. Sci 2020 1:23-31 【Abstract】【PDF】

Abstract

Rapid diagnosis of patients with sepsis or septic shock is critical to improve care and reduce morbidity and mortality. Traditional diagnostic methods such as blood cultures and complete blood count analyses are non-specific and do not always correlate with the patient condition. In addition, blood cultures may not be positive even in confirmed cases of sepsis and may take 48 hours or longer for confirmation. Alternative diagnostic methods such as biomarkers, have been investigated for their possible value in prediction, diagnosis, and management of patients with sepsis. Biomarkers are compounds associated with a particular condition, organ, or disease state. An ideal biomarker should confirm or predict that a patient has sepsis or is at high risk for sepsis. To be effective, these biomarkers must provide high sensitivity and specificity as well as allow testing by methods that are readily available and allow rapid turn-around of results. This study reviews the potential of several biomarkers that are part of the inflammatory reaction during infection and sepsis and those involved in the patients immunologic response to infection. Many of the biomarkers associated with the inflammatory response are non-specific for diagnosis of sepsis but may have a role in monitoring the patients response to therapy. Immune response related biomarkers may help rule-in or rule-out sepsis in patients diagnosed with systemic inflammatory response syndrome. Each of these biomarkers has advantages and disadvantages. The majority of studies have shown that a combination of inflammatory biomarkers and immune response related biomarkers may provide the best diagnostic advantage for rapid confirmation of sepsis.

Key words: sepsis, inflammatory biomarkers, immune regulatory biomarkers, lactate, procalcitonin

Rapid Identification of Pathogens Recovered from Blood Stream Infections

Hassan Aziz, Linda L. Ross, Patricia Tille, Janice Conway-Klaassen

Int. J. Bio. Lab. Sci 2020 1:15-22 【Abstract】【PDF】

Abstract

This study reviews the potential of newer rapid molecular-based methods to identify blood pathogens and/or to predict antibiotic resistance mechanisms that the organisms possess. Use of Peptide Nucleic Acid Fluorescence in Situ Hybridization (PNA-FISH) and matrix-assisted laser desorption ionization Time-of-Flight (MALDI-TOF) technologies are well-established methods for reducing turn-around-time in detecting the bacterial agent in positive blood cultures. Several manufacturers in the US, Europe and South Korea have developed methods and instrumentation to detect microorganisms directly from whole blood specimens without biological amplification on culture media. The assays utilize nucleic acid amplification of the organism DNA or RNA to a detectable level. Challenges with these methods are numerous as pathogens are present in low numbers in the circulating blood and the high background of human DNA can yield the assays less sensitive and specific. Many of the methods are not FDA-approved for use in the US although some have regulatory approval in Europe. Current rapid methods do not replace the traditional methods of culturing positive blood culture isolates to agar plates for definitive identification and antimicrobial susceptibility testing. Recent technological advances are making significant progress in the prompt detection and identification of pathogens and their antimicrobial resistance mechanisms in patients with sepsis. These new rapid methods show promise in the enhancement of patient care and positively influencing patient outcomes. Clinical and economic benefits of the rapid tests must be evaluated in conjunction with a robust antimicrobial stewardship program.

Key words: Blood Stream Infections, Pathogens, Blood cultures, Sepsis, molecular methods

Septicemia: An Extreme Host Response to a Global Healthcare Problem

Patricia Tille, Hassan Aziz, Janice Conway-Klaassenc

Int. J. Bio. Lab. Sci 2020 1:1-6 【Abstract】【PDF】

Abstract

The invasion of the bloodstream by an infectious agent, is one of the most serious and life threatening conditions and a growing worldwide healthcare concern. In addition, there has been significant controversy regarding the risk factors associated with the development of blood stream infections, the classification of these infections, diagnostic criteria and treatment. Many other factors such as the infecting microorganism and geographical location play an intricate role in the development of blood stream infections. This paper is an introduction to a series of reviews concerning the changing laboratory diagnostics of sepsis from traditional microbiology, to molecular diagnostics and automation, and a variety of physiologically relevant biomarkers. An understanding of the brief history, definition of and ambiguity associated with the classification of sepsis and related blood stream infections including septic shock and the systemic inflammatory response syndrome (SIRS) is necessary in order to examine the use of traditional microbiological methods, the use of biomarkers and the introduction of molecular diagnostics and automation in the evolution of sepsis management in order to improve patient care, prognosis and treatment of sepsis in a global healthcare environment.

Key words: septicemia, sepsis, severe sepsis, bloodstream infections, septic shock

Role of the Microbiology Laboratory in the Diagnosis of Sepsis

Hassan Aziz, Linda L. Ross, Janice Conway-Klaassen, Patricia Tille

Int. J. Bio. Lab. Sci 2020 1:7-14 【Abstract】【PDF】

Abstract

Management of patients with sepsis remains a challenge for clinicians despite advances in medical interventions. Sepsis is associated with high morbidity and mortality. Lack of early diagnosis of sepsis is at the core of the issue. Sepsis requires early diagnosis and prompt implementation of the treatment and the clinical microbiology lab is key in the process. Blood cultures historically represent the "gold standard" for diagnosis of septicemia. Pre-analytic factors that influence the recovery of an organism from the blood include the blood volume collected, the number of blood culture bottles collected, and avoidance of skin flora contamination during collection. Numerous methods of commercially available detection systems are available to clinical microbiology labs to choose from and they include both manual methods and automated continuous-monitoring systems. Time to detection of positive cultures varies with the method utilized and the organism recovered. Gram stain, acridine orange stain and other staining techniques can be employed to visualize organisms and the interpretation of the stain is reported immediately to the physician for targeted treatment. Although blood agar and chocolate agar culture plates are generally inoculated for organism isolation, special techniques and extended incubation time may be required for fastidious organisms. Limitations of culture-based methods for detection of sepsis include that positive results require hours to days of incubation. No one culture medium or system in use has been shown to be best suited to the detection of all potential bloodstream pathogens. Some microorganisms grow poorly, or not at all, using blood culture systems and conventional blood culture media. Questions remain for microbiology laboratorians, will culture-based systems continue to be the methods of choice or will they be replaced by molecular techniques or newer diagnostic methods?

Key words: Literature review, blood cultures, sepsis, microbiology, septicemia

International Journal of Biomedical Laboratory Science (IJBLS) Vol. 9, No. 1:1-31

March, 2020

CONTENTS

Original Articles

► Septicemia: An Extreme Host Response to a Global Healthcare Problem

Patricia Tille, Hassan Aziz, Janice Conway-Klaassenc

Int. J. Bio. Lab. Sci 2020 1:1-6 【Abstract】【PDF】

► Role of the Microbiology Laboratory in the Diagnosis of Sepsis

Hassan Aziz, Linda L. Ross, Janice Conway-Klaassen, Patricia Tille

Int. J. Bio. Lab. Sci 2020 1:7-14 【Abstract】【PDF】

► Rapid Identification of Pathogens Recovered from Blood Stream Infections

Hassan Aziz, Linda L. Ross, Patricia Tille, Janice Conway-Klaassen

Int. J. Bio. Lab. Sci 2020 1:15-22 【Abstract】【PDF】

► The Use of Biomarkers in the Diagnosis and Management of Sepsis

Janice Conway-Klaassen, Patricia Tille, Hassan Aziz

Int. J. Bio. Lab. Sci 2020 1:23-31 【Abstract】【PDF】

Published 【PDF】

2020 Vol.9. No1

Articles 2020

About the Journal

Current Issue

Statistics