Optimizing Diagnosis & Management of Bartonella Infection

Research suggests that persistent infections are drivers of inflammatory symptoms, and many organisms have been strongly linked to chronic illness. One of the more recently appreciated microbes associated with human illness is Bartonella. Although one manifestation of Bartonellosis is “cat scratch disease” (Bartonella henselae), research is now showing that a persistent Bartonella bacteremia may contribute to wide-ranging chronic symptomatology, even in those who are immunocompetent. There are now over 28 characterized Bartonella species, 12 of which have been documented as human pathogens. Bartonella Alpha-Proteobacteria Growth Medium Traditionally, serology and polymerase chain reaction (PCR) assays have been used to diagnose Bartonella, but false negative rates can be high. To address these shortcomings, researchers have developed a novel way to document Bartonella infection. Using Bartonella alpha-proteobacteria growth medium (BAPGM) prior to PCR testing has been shown to increase diagnostic sensitivity by at least four-fold when compared with standard PCR alone. This BAPGM-PCR testing method is called Bartonella ePCR (Galaxy Diagnostics). Studies using this testing strategy have implicated Bartonella infection in a broad range of disorders that affect the cardiovascular, lymphatic, musculoskeletal, and central nervous systems. Patients with a history of exposure to fleas (especially cat fleas), ticks, body lice, biting flies, and animal bites and scratches appear to be at particularly high risk. Although more investigations are needed, current research suggests that symptoms of Bartonella infection may include recurring fever, headaches, insomnia, joint and muscle pain, arthropathy, myalgia, neurologic dysfunction, and vasculitis. Physical findings may include lymphadenopathy, splenomegaly, and vasoproliferative tumors, as well as splenic and hepatic granulomas. Evolving Knowledge for Treating Bartonella An unequivocal treatment for all Bartonella infections does...
Critical Considerations for Blood Culture

Critical Considerations for Blood Culture

Sepsis and septic shock are leading causes of morbidity and mortality in the United States and represent an increasing problem for patients, providers, and healthcare systems. Studies indicate that these conditions contribute to more than 20,000 deaths per day worldwide. Despite the emergence of newer microbiology technologies, blood cultures continue to be indispensable tests for the microbiology laboratory. Positive blood cultures are often a critical step in diagnosing sepsis and are required for downstream identification and susceptibility testing. Significant advances have been made in automated blood culture systems, including the addition of enriched growth media, enhancements in automated agitation systems, and improved growth algorithms. Despite the progress, obtaining blood cultures before initiating anti-infective therapy and ensuring appropriate fill volumes of 20 mL to 40 mL of blood per venipuncture remain key factors in the successful detection of adult bacteremia. In some healthcare settings, anaerobic bacteremia has reemerged as a significant clinical problem, most likely due to more patients presenting to these institutions with complex underlying diseases. Reaching Clinical Goals Initiation of prompt, appropriate antimicrobial therapy in patients at risk for sepsis is a critical clinical goal, but doing so before culture collection may delay or prevent pathogen recovery. To address this issue, blood culture manufacturers have incorporated blood-broth ratios and/or proprietary antimicrobial removal systems into media to minimize the impact of antimicrobials and facilitate pathogen detection. For example, the BACTEC Plus (Becton Dickinson) and BacT/Alert (bioMérieux) are two frequently used aerobic blood culture media that incorporate the use of proprietary antimicrobial removal systems. The BACTEC medium uses proprietary resin beads, whereas the BacT/Alert medium uses Ecosorb (a blend of...