Tags: Chancroid

Haemophilus, Bordetella, & Branhamella Species

Before 1990, strains of Haemophilus influenzae type b were found in the upper respiratory tract of 3-5% of children and a small percentage of adults. Colonization rates with type-b strains are even lower now, reflecting routine immunization of infants against H influenzae type b. Non-type-b encapsulated H influenzae are present in the nasopharynx of < 2% of individuals, whereas nonencapsulated (nontypable [see below]) strains colonize the respiratory tract of 40-80% of children and adults.

Haemophilus Influenzae: Clinical Syndromes

H influenzae was first isolated during the 1892 influenza pandemic and was originally believed to be the causative agent of influenza. Although subsequent studies revealed the fallacy of this idea, H influenzae has proved to be a common cause of localized respiratory tract and systemic disease, including meningitis, epiglottitis, pneumonia, pyogenic arthritis, cellulitis, otitis media, and sinusitis, among others (Box 1). Meningitis is the most common and serious form of invasive H influenzae type-b disease. In the mid-1980s, before the introduction of effective vaccines, ~ 10,000-12,000 cases of H influenzae type-b meningitis occurred in the United States each year, and 95% of cases involved children < 5 years old.

Specific Anti-Infective Agents

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 each class can be subtle, often requiring the expertise of an infectious disease specialist to design the optimal anti-infective regimen. The general internist or physician-in-training should not attempt to memorize all the facts outlined here, but rather should read the pages that follow as an overview of anti-infectives. The chemistry, mechanisms of action, major toxicities, spectrum of activity, treatment indications, pharmacokinetics, dosing regimens, and cost are reviewed.

Sexually Transmitted Diseases: Trichomoniasis

The spectrum of sexually transmitted diseases includes the classic venereal diseases – gonorrhea, syphilis, chancroid, lymphogranuloma venereum, and granuloma inguinale – as well as a variety of other pathogens known to be spread by sexual contact (Table Sexually Transmitted Diseases). Common clinical syndromes associated with sexually transmitted diseases are listed in Table Selected Syndromes Associated with Common Sexually Transmitted Pathogens.

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.

Epidemiologic and virulence factors in infectious diseases

Before appropriate therapy can be given for an infectious disease, consideration of epidemiologic factors is essential. This section does not fully discuss the epidemiology (the determinants, occurrence, distribution, and control of health and disease) of infectious diseases. However, a number of basic principles and historical points are worth emphasizing.

Macrolides: Erythromycin, Clarithromycin, Azithromycin

Erythromycin is a macrolide antibiotic that binds to the 50-S subunit of the ribosomes. It kills susceptible bacteria by interfering with their protein synthesis.

Tetracyclines General Statement: Uses

Tetracyclines are used principally in the treatment of infections caused by susceptible Rickettsia, Chlamydia, Mycoplasma, and a variety of uncommon gram-negative and gram-positive bacteria.

Sulfonamides General Statement

Sulfonamides, synthetic derivatives of p-aminobenzenesulfonamide (sulfanilamide), are classified as anti-infectives if they possess antibacterial activity that is antagonized by p-aminobenzoic acid or p-aminobenzoyl glutamic acid.