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
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