Clinical Microbiology Newsletter最新文献

The introduction of sophisticated molecular technologies (16S rRNA gene sequencing, matrix-assisted laser desorption ionization–time of flight [MALDI-TOF], and whole-genome sequencing) into many clinical and diagnostic microbiology laboratories has brought with it enhanced capabilities for the accurate identification of many prokaryotic species not resolvable by common phenotypic or commercially automated methods. Along with this heightened capacity to provide highly accurate bacterial identifications have come some indirect consequences that may not be entirely appreciated by the scientific community. Some examples of these consequences are a transitional approach to training and a different skill set for current laboratorians, a quickly changing bacterial taxonomy, and peer-reviewed literature requiring much closer scrutiny. This article provides an overview of the present situation and challenges to microbiologists as the field moves forward.

Group A Streptococcus, or Streptococcus pyogenes, is a facultatively anaerobic Gram-positive coccus and one of the most common causes of bacterial infection in humans. The introduction of antibiotics has greatly reduced the morbidity and mortality associated with this organism, but despite uniform susceptibility to treatments of choice, it remains a significant human pathogen. It is particularly problematic in underdeveloped and lower socioeconomic status countries, where hygiene may be suboptimal. This review covers a wide range of topics related to the organism, including diagnosis, treatment, and clinical manifestations. Where possible, the review addresses less conventional and often controversial topics that have not been extensively reviewed elsewhere, such as the activity of trimethoprim sulfamethoxazole against the species, penicillin tolerance, and the use of protein synthesis inhibitors to reduce toxin production and improve outcomes.

The indications for and interest in self-collection of specimens, such as blood, saliva, urine, stool, and anogenital specimens, for clinical laboratory testing are vast (especially in the post-pandemic era). A need for innovation, combined with convenience for patients, clinicians, and researchers, opened the doors for a wave of self-collection devices to flood the market in early 2020. Many of the devices discussed in this review are registered by the U.S. Food and Drug Administration (FDA) or have emergency use authorization for diagnostic testing in clinical laboratories. While many self-collection devices were evaluated for collection of specimens for SARS-CoV-2 testing, they can be used to collect samples for many other serologic, molecular, or other diagnostic methods following completion of necessary laboratory validation studies. The advantages of these devices, such as convenience and access, must be balanced with added cost, challenges of specimen stability, and manual processing in the laboratory, all of which are discussed in this review.

Despite pneumonia being a leading cause of morbidity and mortality worldwide, diagnostics remains a challenge, hindering rapid organism identification and subsequent effective treatments. Current microbiological methods include culture, serology, and limited molecular panels. While helpful, these methods are unable to address the full range of potential pathogens (e.g., fastidious or noncultivable organisms or uncommon organisms not included in current panels). Metagenomic next-generation sequencing (mNGS) is a molecular technique that analyzes and compares the nucleic acid content in a patient sample to a reference database of organisms that may include bacteria, viruses, fungi, and/or parasites, depending on the mNGS technology used. By bypassing the limitations of culture and targeted molecular assays, mNGS offers the potential to identify countless organisms directly from a patient specimen to aid in the diagnosis of an infectious process. Although promising, mNGS does have considerable limitations related to cost, interpretation, standardization, clinical relevance, turnaround time (TAT), and widespread availability. Thus, these factors should be considered prior to implementing mNGS for clinical use. Moreover, additional studies are required to fully understand the clinical and epidemiological impact of mNGS for the diagnosis of infectious diseases, including respiratory infections.

Onychomycosis is a fungal infection that can occur within the nails of the fingers and the toes. These infections can lead to discoloration and thickening of the nails, as well as separation of the nails from the bed and their splitting, and ultimately nail destruction. Although predominantly caused by dermatophytes, which have keratinolytic properties, several other groups of fungi can also cause this type of infection, including nondermatophyte molds (both hyaline and dematiaceous) and yeasts, such as Candida species. Proper identification of the etiologic agent is important, as it may influence the treatment of these infections. Here, we review the mycology of onychomycosis and describe recent changes in fungal taxonomy that have occurred with several of these fungi.

Diabetes mellitus is one of the most prevalent chronic diseases in the United States and is associated with a high incidence of infectious complications. These complications lead to increased morbidity, mortality, and utilization of the health care system by a large subset of the worldwide population. The mechanisms contributing to infection in a person living with diabetes are complex and include underlying pathology affecting physiologic functions ranging from adaptive immunity to skin integrity. In this review, we aim to summarize what is known about these pathologies. We highlight how common infections are unique and how certain unique infections are more common in persons with diabetes. Finally, we discuss the clinical presentations and diagnostic considerations pertinent to persons with diabetes.

Antimicrobial resistance (AMR) is a global health crisis, and the development of new antimicrobials is essential to reducing associated morbidity and mortality. Infections by multi-drug-resistant Gram-negative bacteria have been at the forefront of this AMR public health emergency, often overshadowing the importance of novel treatment options for multi-drug-resistant Gram-positive bacterial infections. Here, we introduce and review a number of antimicrobial agents with activity against clinically significant Gram-positive pathogens, including difficult-to-treat staphylococci, streptococci, enterococci, and Gram-positive anaerobes. We describe antimicrobial agents in late-stage development, those that are newly approved, and those with existing FDA-approved clinical indications for which more recently the FDA expanded approval for novel indications. Overall, the goal of this review is to provide clinical microbiologists, infectious disease physicians, and pharmacists with current, relevant information about novel antibiotic agents effective against Gram-positive bacteria.