MEDT 430/431 Diagnostic Bacteriology and Medical Mycology

Course Goals

Diagnostic Bacteriology (Part I) and Medical Mycology (Part II) are focused on bacterial and fungal pathogens. As with any new discipline, it is important that the student start by learning the fundamentals. Essential background material necessary for interpretation of clinical microbiology results has already been learned in the companion course Medical Microbiology (MEDT406/416). You should already be familiar with the routine specimens received for culture, the common pathogens isolated, and tests used to identify those pathogens. These fundamentals should serve you well in the Diagnostic Bacteriology laboratory where pathogens will be isolated from (as much as possible) specimens obtained from patients. In addition, you will learn more fundamentals: from the proper collection and handling of specimens to their proper disposal, and everything in between. The "in between" part involves identification of organisms and determining antibiotic susceptibility patterns. Sounds simple enough - but it can be likened to a chess game. In chess, the object is simply to capture a king, but the strategies and decisions involved can be very complicated. Similarly, a large part of the microbiology lectures will be devoted to factors and strategies that enable one to make decisions in various clinical situations, some of which may be very complicated.

In Part II, Medical Mycology, fungi that cause human disease will be studied. During the past few decades, reports of fungal infections have increased as advances in medical technology and development of new treatment approaches has extended life expectancy. National Nosocomial Infections Surveillance System data show that fungi account for 9% of all nosocomial infections. Most common fungal pathogens associated with invasive disease in humans are opportunistic yeasts (e.g., Candida albicans) or filamentous fungi (e.g., Aspergillus species). Fungi previously thought to be nonpathogenic for humans or only sporadically associated with human disease, such as Candida species other than C. albicans, Fusarium, Trichosporon, and Malassezia species, are emerging as important nosocomial fungal pathogens. These pathogens are associated with significant mortality, exceeding 50% mortality in most studies.

Risk factors for opportunistic fungal infections include previous antimicrobial therapy, chemotherapy, presence of indwelling intravascular catheters, neutropenia, prior hemodialysis, or previous fungal colonization. These factors are common in hospitalized patients, especially in high-risk areas such as ICUs and oncology wards. Thus, species identification of fungal isolates is becoming an increasingly important function of clinical microbiology. However, with the exception of yeast assimilation and fermentation tests, there are few biochemical tests used to identify fungi. Therefore, the identification of medically important fungi relies heavily on morphology: both macroscopic (colony characteristics) and microscopic (hyphae and reproductive structures). In the laboratory the student will observe and identify many of these important morphologic characteristics used to differentiate fungal species. The lecture is designed to complement this practical experience. We will discuss laboratory findings, together with clinical presentations and epidemiological factors important in diagnosis of fungal diseases.

One goal of MEDT 430 is to aid the student in integration of laboratory findings, patient history and symptoms, and epidemiological data to establish the etiological cause of infection. Finally, the major goal of this course is to prepare all MT students for their clinical rotations and a career in the medical microbiology laboratory.

Diagnostic Bacteriology and Medical Mycology Laboratory (MEDT431) is a springboard for students ready to dive into medical laboratory microbiology. This particular discipline is focused on bacterial pathogens. As with any new discipline, it is important that the student start by learning the fundamentals. Some of these fundamentals have already been learned in the companion course Medical Microbiology (MEDT 406/416). You should be familiar with the routine specimens received for culture, the common pathogens isolated, and how to identify those pathogens. These fundamentals should serve you well in the Diagnostic Microbiology lab where pathogens will be isolated from (as much as possible) actual patient specimens. In addition, you will learn more fundamentals; from the proper collection and handling of specimens to their proper disposal, and everything in between.

The "in between" part involves identification of organisms and determining antibiotic susceptibility patterns. Sounds simple enough - but it can be likened to a chess game. In chess, the object is simply to capture a king, but the strategies and decisions involved can be very complicated. Similarly, a large part of the Microbiology lectures will be devoted to factors and strategies that enable one to make decisions in various clinical situations, some of which may be very complicated. Returning to the original (or at least the first) metaphor, a major goal is that all MT students will make a big splash in their clinical rotations, and if their fundamentals are sound, they can do so (without getting all wet).

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Instructor

Michelle Parent , Ph.D., MT(ASCP)
Office:305H WHL
Phone Number: 302-831-8591
e-mail: mparent@udel.edu

Laboratory Instructor

Heather Walters, B.S. MT(ASCP)
Office: 305D WHL
Phone Number: 302-831-4212
e-mail: hwalters@udel.edu