Clinical Microbiology Newsletter最新文献

Unlike adult blood cultures, pediatric blood culture practices are less clear-cut. The various existing guidelines differ on blood collection volume and culture conditions due to the unique characteristics of pediatric blood culture, such as the potential for increased contamination and low blood volume. There are some specialized products marketed for pediatric populations to address these issues, including initial specimen diversion devices and low-volume blood culture bottles. However, there are scant studies looking at their effectiveness. This review discusses the current epidemiology of pediatric bacteremia, the most recently published evidence for the pediatric blood culture practices, and where technology may be going in the future for detection of pediatric bloodstream infections.

The analytic process for identification of anaerobic bacteria involves direct specimen Gram stains and workup of growth in culture. Direct Gram stains help to develop the initial differential, aiding in guiding both the extent of laboratory workup and clinician decision making for patient management. Workup of anaerobic growth should involve an aerotolerance test to assess aerobic growth and to compare growth rates in anaerobic versus aerobic environments. While matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has become a routine means of anaerobe identification for many clinical laboratories, spot biochemical tests, such as indole and catalase, should be available in every laboratory that identifies anaerobes. If MALDI-TOF MS and biochemical methods are unsuccessful at providing an identification, 16S rRNA gene PCR and/or sequencing may be performed if the information impacts clinical care. The extent of culture workup to the level of presumptive identification versus definitive identification depends upon several factors, including the specimen source, direct Gram stain results, and the presence or absence of mixed microbiota. In addition to discussing the current best practices for anaerobic culture workup, commonly encountered anaerobic organism Gram stains and culture growth are detailed.

Human herpesvirus 6 (HHV-6) causes primary infection in early childhood and establishes lifelong latency in its host. Reactivation of HHV-6, especially in immunosuppressed patients, has been associated with a variety of clinical complications. Diagnosis of acute HHV-6 infection has been a major challenge due to high prevalence of the virus and the difficulty in distinguishing latent infections from acute. Chromosomal integration of HHV-6 also occurs further complicating the management and diagnostics of HHV-6 disease. PCR-based methods have become the mainstay of HHV-6 diagnostics, however, interpretation of results in the context of clinical disease is of utmost importance.

Maybe 2021 wasn’t so bad after all! It was like 2020, but with COVID vaccines and better access to plastic pipette tips, and clearly, 2022 is getting off to a bad start. Even better, 2021 had some exciting papers in clinical microbiology, which is what is highlighted in this 2021 year in review. None of them are about COVID-19. Of course, there were some interesting discoveries about SARS-CoV-2 and COVID-19, but this review is completely COVID-19 free (almost).

Anaerobic bacteria that cause infections contribute to patient morbidity and mortality, especially among patients with underlying conditions or who are immunocompromised. While once largely grouped together without specific differentiation, anaerobic bacteria, defined as organisms that utilize terminal electron acceptors other than oxygen, are of increasing importance in clinical microbiology. In this review, we discuss pre-analytical-phase best practices for anaerobic recovery in the clinical microbiology laboratory. The suspected infection, and in turn the type of specimen to be cultured, helps determine which sample container, specimen collection method, transport conditions, and culture media are needed for optimal recovery of anaerobic bacteria.