No abstract

SUMMARY The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.

Herpes infections are among the most common sexually transmitted diseases and are the most common cause of genital ulcer disease in the United States. This study addresses the changing distribution of herpes simplex virus type 1 (HSV-1) and HSV-2 in patients presenting for evaluation of herpetic infections. Viral culture results from the University of Kentucky Clinical Microbiology Laboratory were reviewed for a 6-year period (1994 through 1999). Data were collected on patient sex, site of culture, and culture result. These data were analyzed statistically to identify yearly trends. Of the 4,498 cultures analyzed, nearly equal proportions of HSV-1 (13.3%) and HSV-2 (12.0%) were detected for an overall culture positivity rate of 25.3%. Approximately two-thirds of all positive cultures were from women. Although HSV-2 remained the predominant type of genital herpes, over the 6-year span of this study, there was a trend toward increasing proportions of HSV-1 genitalis, with 31.8% of male patients and 44.8% of female patients demonstrating HSV-1 genitalis by 1999. The majority of patients with HSV in nongenital sites grew HSV-1. Although there was significant yearly variation, HSV-2 was isolated from only 9.4% of patients with nongenital HSV for the entire 6-year period. This study therefore concludes that HSV-2 remains primarily a genital pathogen, while HSV-1 is taking on an increasingly important role in causing genital ulcer disease in addition to being the primary nongenital HSV.

MRL Diagnostics and Meridian Diagnostics have recently designed herpes simplex virus type 2 (HSV-2)-specific enzyme immunoassays for HSV-2 antibody detection. Blood donor sera were assayed for HSV-2 antibodies by both methods. The sensitivity, specificity, and efficiency were 97.9, 95.4, and 95.9% for the MRL assay and 83.2, 98.2, and 95.5% for the Meridian assay, respectively.Detection of disease caused by herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) has been complicated by the lack of availability of consistently good diagnostic testing. Although culture is definitive in making a diagnosis, the timing of culture is critical for success. Culture during periods of active disease produces optimal recovery rates (6, 8). Reliance on culture for the detection of genital ulcer disease caused by herpes simplex viruses may result in underdiagnosis of the condition (7). Direct antigen detection techniques are not reliable since they appear to be only 50% as sensitive as optimal viral isolation procedures (5). Although PCR detection of viral shedding has been described as a much more sensitive method than culture for the detection of viral shedding, this method is not currently available for clinical diagnosis (2). Supplementing culture with direct fluorescent antibody staining specific for HSV-1 or HSV-2 may yield a diagnosis even when the culture is negative (12), but many institutions do not offer this method of diagnostic testing. Other diagnostic tests, including Pap smears, Giemsa-stained preparations, and many of the point-of-care antigen detection assays, do not differentiate between HSV-1 and HSV-2 infections. Since the type of HSV implicated in disease has ramifications for prognosis (9,14), it is important to specify the HSV subtype.Early application of type-specific serologic testing for HSV-1 and HSV-2 has been shown to be of benefit in testing firsttime, recurrent, and asymptomatic infections as a means to definitive diagnosis and appropriate patient and spouse counseling (10). A seronegative status may be seen in patients with acute infection or in those at risk for acquiring infection, while a seropositive status is seen in patients with latent or recurrent infections. Until recently, enzyme immunoassays (EIAs) utilized either whole virus antigen preparations or type-specific antigenic determinants with extensive HSV-1 and HSV-2 immunologic response cross-reactivity (4). Since HSV-1 and HSV-2 share many common antigenic determinants (11, 13), these assays cannot be used reliably to differentiate HSV-1-from HSV-2-infected individuals. Western blot assays, although capable of differentiating antibodies against HSV-1 and -2, are expensive and are not readily available to most clinical laboratories (1). The identification of type-specific glycoproteins G1 (gG1; HSV-1-specific antigen) and G2 (gG2; HSV-2-specific antigen) led to the development of bulk protein production for type-specific assays. Recently, two manufacturers, MRL Diagnostics Inc. (Cincinnati, Ohio) and Meridian Diagnostics (Cypress, C...

The use of assisted reproduction treatment, especially intracytoplasmic sperm injection (ICSI), is now linked to a range of adverse consequences, the aetiology of which remains largely undefined. The objective was to determine differences in gene expression of blastocysts generated by ICSI as well as ICSI with artificial oocyte activation (ICSI-A) versus the less manipulative IVF, providing fundamental genetic information that can be used to aid in the diagnosis or treatment of those adversely affected by assisted reproduction treatment, as well as stimulate research to further refine these techniques. Murine blastocysts were generated by ICSI, ICSI-A and IVF, and processed for a microarray-based analysis of gene expression. Ten blastocysts were pooled for each procedure and three independent replicates generated. The data were then processed to determine differential gene expression and to identify biological pathways affected by the procedures. In blastocysts derived by ICSI versus IVF, the expression of 197 genes differed (P < 0.01). In blastocysts derived by ICSI-A versus IVF and ICSI-A versus ICSI, the expression of 132 and 65 genes differed respectively (P < 0.01). Procedural-induced changes in genes regulating specific biological pathways revealed some consistency to known adverse consequences. Detailed investigation of procedure-specific dysfunction is therefore warranted.