55 Tissue Nematodes
TOXOCARA TOXOCARA CANIS: PARASITOLOGY AND LIFE CYCLE (FIGURE 55–1) FIGURE 55–1. Life cycle of Toxocara canis. (Reproduced with permission from Roberts RL, Janovy J, Nadler S: Foundations of Parasitology, 9th…
56 Cestodes
Clinical effects depend on whether humans are definitive hosts or intermediate hosts Tissue cysts, not intestinal worms, cause serious disease PARASITOLOGY MORPHOLOGY Like all helminths, tapeworms lack vascular and respiratory…
53 Sarcomastigophora—The Flagellates
Found in flora of vertebrates These organisms are elongated or oval and typically measure 10 to 20 μm in length. They often possess a rudimentary cytostome (mouth aperture) and organelles,…
27 Mycobacteria
BACTERIOLOGY STRUCTURE The mycobacteria are slim, poorly staining bacilli, which demonstrate the property of acid-fastness. They are nonmotile, obligate aerobes that do not form spores. The cell wall contains peptidoglycan…
30 Neisseria
FIGURE 30–1. Neisseria gonorrhoeae. Gram stain of urethral exudate. Note the many pairs of Gram-negative bean-shaped diplococci (arrow) collected in polymorphonuclear neutrophils (PMNs) and free in the purulent material. The…
23 Antibacterial Agents and Resistance
Definitions • Antibiotics—antimicrobials of microbial origin, most of which are produced by fungi or by bacteria of the genus Streptomyces. • Antimicrobials—substances used in the treatment of infectious diseases. In…
4 Principles of Laboratory Diagnosis of Infectious Diseases
FIGURE 4–1. Specimens for the diagnosis of infection. A. Direct specimen. The pathogen is localized in an otherwise sterile site, and a barrier such as the skin must be passed…
47 Cryptococcus, Histoplasma, Coccidioides, and Other Systemic Fungal Pathogens
CRYPTOCOCCUS CRYPTOCOCCUS NEOFORMANS and CRYPTOCOCCUS GATTII Cryptococcus is a genus of yeast 4 to 6 μm in diameter that produces a characteristic capsule (Figure 47–1), extending the overall diameter to…
13 Hepatitis Viruses
HEPATITIS A VIROLOGY Hepatitis A virus (HAV) belongs to the Picornaviridae (picornaviruses) family and Hepato-virus genus. It is an unenveloped (naked capsid), single-stranded, positive-sense RNA virus with a cubic (icosahedral)…
24 Staphylococci
FIGURE 24–1. Staphylococcus aureus. Gram stain showing the Gram-positive cocci in clusters resembling bunches of grapes (arrows) and neutrophils (arrowhead). (Image contributed by Professor Shirley Lowe, University of California, San…
