Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences.
Although not as ubiquitous as antibacterial susceptibility testing, antifungal susceptibility testing (AFST) is a tool of increasing importance in clinical microbiology laboratories. The goal of AFST is to reliably produce MIC values that may be used to guide patient therapy, inform epidemiological studies, and track rates of antifungal drug resistance. There are three methods that have been standardized by standards development organizations: broth dilution, disk diffusion, and azole agar screening for Aspergillus. SUMMARY Although not as ubiquitous as antibacterial susceptibility testing, antifungal susceptibility testing (AFST) is a tool of increasing importance in clinical microbiology laboratories. The goal of AFST is to reliably produce MIC values that may be used to guide patient therapy, inform epidemiological studies, and track rates of antifungal drug resistance. There are three methods that have been standardized by standards development organizations: broth dilution, disk diffusion, and azole agar screening for Aspergillus. Other commonly used methods include gradient diffusion and the use of rapid automated instruments. Novel methodologies for susceptibility testing are in development. It is important for laboratories to consider not only the method of testing but also the interpretation (or lack thereof) of in vitro data.
Schwyn and Neiland developed a universal siderophore assay using chrome azurol S(CAS) and hexadecyltrimethylammonium bromide (HDTMA) as indicators. In Schwyn and Neiland’s original paper, the procedure given for making CAS agar is written in general terms and can be difficult to follow, especially for an individual who has limited experience making more complex media. Here, we give a step-by-step protocol for making the CAS agar plates, and we discuss how this media can be incorporated in a comprehensive project in a microbiology lab course for biology majors.
Abstract Background Many transfeminine people (assigned male at birth with feminine gender identities) undergo vaginoplasty, a surgical procedure constructing a neovagina, typically using penile and scrotal tissue. In cisgender females, gynecological symptoms (pain, discharge, malodor) are often attributed to bacterial vaginosis, which can be diagnosed using Nugent scoring of gram-stained vaginal smears. The Nugent score assesses the abundance of large gram-positive rods versus small or curved gram-variable rods, traditionally for the detection of Lactobacillus, Gardnerella vaginalis, and Mobiluncus, respectively. Although unvalidated, this method is frequently applied to neovaginal samples to diagnose gynecological symptoms and dysbiosis. This study assessed the Nugent score’s utility for diagnosing neovaginal dysbiosis in transfeminine people. Methods As a part of the TransBiota study, n = 39 transfeminine participants self-collected neovaginal smears. Smears were Gram stained and Nugent scored, and scores were correlated with data on neovaginal bacterial composition (16S rRNA gene sequencing), neovaginal cytokines (Luminex multiplex immunoassay), and self-reported symptoms. Results We show more than 70% of neovaginal smears fell in the 7-10 Nugent score range, indicative of Bacterial Vaginosis in cisgender women. However, scores fail to correlate with the abundance of Nugent-targeted bacteria. Bacteria with similar morphotypes, but not belonging to Lactobacillus, Gardnerella, or Mobiluncus, are highly abundant and prevalent in the neovagina. Nugent score also fails to predict local inflammation or clinical symptoms. Conclusions The Nugent score is not an effective tool to identify neovaginal dysbiosis or indicators of health in transfeminine individuals. Clinicians need the development of accurate, evidence-based diagnostic tools for the neovagina.