Tags: Ceftizoxime

Toxin-Mediated Infections

1. TETANUS Tetanus is a disease of global incidence produced by the toxin of Clostridium tetani. The risk of acquiring it increases in people > 60 years of age and in neonates, especially in Third World countries where poor sanitary conditions predispose to umbilical stump contamination. Immunization campaigns have played a crucial role in bringing about the observed decreasing incidence in the United States. The pathogenesis of tetanus involves the absorption of preformed toxin, or, less commonly, invasion of toxin-producing organisms from contaminated wounds; it may complicate surgical wounds colonized with C tetani. Incubation periods vary depending on the portal of entry. The toxin tetanospasmin blocks the transmission of inhibitory neurons, …

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Specific Causes Of Acute Community-Acquired Pneumonia

Great overlap occurs among the clinical manifestations of the pathogens associated with acute community-acquired pneumonia. However, constellations of symptoms, signs, and laboratory findings serve to narrow the possibilities. By developing an ability to focus on a few pathogens or to identify a specific pathogen, clinicians can better predict the clinical course of pneumonia and can narrow antibiotic coverage. Streptococcus pneumoniae Pathogenesis Pathogenic strains of S. pneumoniae have a thick capsule that prevents PMN binding and that blocks phagocytosis. Certain capsular types (1, 3, 4, 7, 8, and 12 in adults, and 3, 6, 14, 18, 19, and 23 in children) account for most pneumonia cases. Type 3 has the thickest polysaccharide …

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Anti-Infective Agent Dosing

The characteristics that need to be considered when administering antibiotics include absorption (when dealing with oral antibiotics), volume of distribution, metabolism, and excretion. These factors determine the dose of each drug and the time interval of administration. To effectively clear a bacterial infection, serum levels of the antibiotic need to be maintained above the minimum inhibitory concentration for a significant period. For each pathogen, the minimum inhibitory concentration is determined by serially diluting the antibiotic into liquid medium containing 104 bacteria per millihter. Inoculated tubes are incubated overnight until broth without added antibiotic has become cloudy or turbid as a result of bacterial growth. The lowest concentration of antibiotic that prevents …

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Specific Anti-Infective Agents

Antibiotics Before prescribing a specific antibiotic, clinicians should be able to answer these questions: •  How does the antibiotic kill or inhibit bacterial growth? •  What are the antibiotic’s toxicities and how should they be monitored? •  How is the drug metabolized, and what are the dosing recommendations? Does the dosing schedule need to be modified in patients with renal dysfunction? •  What are the indications for using each specific antibiotic? •  How broad is the antibiotic’s antimicrobial spectrum? •  How much does the antibiotic cost? Clinicians should be familiar with the general classes of antibiotics, their mechanisms of action, and their major toxicities. The differences between the specific antibiotics in …

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Skin and Soft Tissue Infections

Definition Bacterial infections of the skin can be classified as primary (pyodermas or cellulitis) or secondary (invasion of the wound) (Table Bacterial Classification of Important Skin and Soft Tissue Infections). Primary bacterial infections are usually caused by a single bacterial species and involve areas of generally healthy skin (e.g., impetigo, erysipelas). Secondary infections, however, develop in areas of previously damaged skin and are frequently polymicrobic in nature. The conditions that may predispose a patient to the development of skin and soft tissue infections include (1) a high concentration of bacteria, (2) excessive moisture of the skin, (3) inadequate blood supply, (4) availability of bacterial nutrients, and (5) damage to the corneal …

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Syphilis

The causative organism of syphilis is Treponema pallidum, a spirochete. Syphilis is usually acquired by sexual contact with infected mucous membranes or cutaneous lesions, although on rare occasions it can be acquired by nonsexual personal contact, accidental inoculation, or blood transfusion. Clinical presentation The clinical presentation of syphilis is varied, with progression through multiple stages possible in untreated or inadequately treat patients (Table Presentation of Syphilis Infections). Primary Syphilis Primary syphilis is characterized by the appearance of a chancre on cutaneous or mucocutaneous tissue. Chancres persist only for 1 to 8 weeks before spontaneously disappearing. TABLE. Treatment of Gonorrhea Type of Infection Recommended Regimensa Alternative Regimensb Uncomplicated infections of the cervix, …

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Intra-abdominal Infections

Definition Intra-abdominal infections are those contained within the peritoneum or retroperitoneal space. Two general types of intra-abdominal infection are discussed throughout this chapter: peritonitis and abscess. Peritonitis is defined as the acute, inflammatory response of peritoneal lining to microorganisms, chemicals, irradiation, or foreign body injury. Peritonitis may be classified as either primary or secondary. With primary peritonitis, an intra-abdominal focus of disease may not be evident. In secondary peritonitis, a focal disease process is evident within the abdomen. An abscess is a purulent collection of fluid separated by a more or less well-defined wall from surrounding tissue. It usually contains necrotic debris, bacteria, and inflammatory cells. Pathophysiology Table Causes of Bacterial …

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Central Nervous System Infections

Definition Central nervous system infections include a wide variety of clinical conditions and etiologies: meningitis, meningoencephalitis, encephalitis, brain and meningeal abscesses, and shunt infections. The focus of this chapter is meningitis. Pathophysiology Infections are the result of hematogenous spread from a primary infection site, seeding from a parameningeal focus, reactivation from a latent site, trauma, or congenital defects in the central nervous system. central nervous system infections may be caused by a variety of bacteria, fungi, viruses, and parasites. The most common causes of bacterial meningitis include Streptococcus pneumoniae, Neisseria meningitides, Listeria monocytogenes, and Haemophilus influenzae. The critical first step in the acquisition of acute bacterial meningitis is nasopharyngeal colonization of …

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Infectious disorders

Infectious diseases comprise those illnesses that are caused by microorganisms or their products. Clinical manifestations of infection occur only when sufficient tissue injury has been inflicted directly by microbial products (e.g., endotoxins and exotoxins), or indirectly by host responses (e.g., cytokines and hydrolytic enzymes released by polymorphonuclear leukocytes). Despite the extraordinary recent advances that have occurred in therapeutics for infectious diseases, a number of basic principles should be followed to prescribe antimicrobials and vaccines is an optimal manner. This chapter addresses the broader issues of treating infectious diseases and provides a number of practical clinical examples to demonstrate rational therapeutics. A rational therapeutic strategy in the management of proved or suspected …

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Antimicrobial therapy: general principles

A wide variety of antimicrobial agents is available to treat established infections caused by bacteria, fungi, viruses, or parasites. This section will cover the general principles of antimicrobial therapy and will also include illustrative clinical problems to emphasize proper decision-making in using antimicrobials. Determinants of Antimicrobial Efficacy Measurement of antimicrobial activity in vitro Susceptibility testing is indicated for any bacterial pathogen warranting chemotherapy. Drugs that irreversibly destroy the ability of an organism to replicate, and perhaps in the process destroy the structural integrity of the organism, are microbicidal. Drugs that reversibly impair replicating ability, with this function being restored when drug concentrations fall below critical inhibitory levels, are microbiostatic. In quantitative …

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