Tags: Pharyngitis

Chlamydia

General Considerations Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae are among the most prevalent microbial pathogens in humans worldwide. C trachomatis is responsible for a variety of sexually transmitted disease (STD) syndromes in both sexes. In addition, certain serotypes of C trachomatis are responsible for trachoma, the most common infectious cause of blindness in humans. C psittaci is a zoonotic pathogen associated with atypical pneumonia. C pneumoniae infects approximately one-half of the world’s human population and is a cause of upper and lower respiratory tract disease. It has also been associated with atherosclerotic cardiovascular disease. A. Epidemiology. In the United States, genital infections by C trachomatis serovars D through K occur …

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M Pneumoniae Infection & Disease

M pneumoniae is an important cause of upper and lower respiratory infections in both adults and children. Extrapulmonary involvement, including dermatological, neurological, cardiac, musculoskeletal, and vasculitic involvement, has also been associated with M pneumoniae infection in humans. Essentials of Diagnosis • Community acquired pneumonia. • Extrapulmonary involvement is not infrequent. • Inflammatory cells on sputum Gram stain but no predominant bacterial type. • Coombs-positive hemolytic anemia. • Cold agglutinin titer of = 1:32. • Fourfold change in specific immunoglobulin G (IgG) or IgM titers. General Considerations A. Epidemiology. Infected humans are the only source of M pneumoniae organisms for transmission to new susceptible hosts. M pneumoniae is spread from one individual …

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Brucella, Francisella, Pasteurella, Yersinia, & Hacek

BRUCELLOSIS Essentials of Diagnosis • Suspected in patients with chronic fever of unknown etiology who have a history of occupational exposure or come from a high prevalence area. • Leukopenia. • Blood culture or bone marrow cultures on appropriate media. • Serum antibody titer = 1:160. • Polymerase chain reaction. General Considerations Brucellosis (also called undulant fever, Mediterranean fever, Malta fever) is an infection that causes abortion in domestic animals. It is caused by one of six species of Brucella coccobacilli. It may occasionally be transmitted to humans, in whom the disease could be acute or chronic with ongoing fever and constitutional symptoms without localized findings. A. Epidemiology. Brucellosis is transmitted …

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Pasteurella

Essentials of Diagnosis • History of a cat or dog bite or other exposure. • Pain, erythema, swelling, and drainage at the bite site. • Gram-negative bipolar bacilli on Gram stain of the drainage. • Culture of the organism confirms the diagnosis. General Considerations Pasteurella multocida infection, a disease that primarily affects animals, may occasionally affect humans, causing a wide variety of infections ranging from soft tissue infection to bacteremia and endocarditis. A. Epidemiology. Pasteurella multocida has been recovered from cultures of specimens from the nasopharynx and the gastrointestinal tract of a large number of asymptomatic wild and domestic animals. The highest carriage rates occur in cats (50%-90%), dogs or swine …

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Yersiniosis

Essentials of Diagnosis • Suspected in a child living in or traveling from a high-prevalence area who has fever, abdominal pain, and diarrhea followed by a reactive polyarthritis. • Yersinia spp. are recovered from cultures of specimens of stool, mesenteric lymph nodes, blood, or abscess material. • Inoculation of duplicate sets of cultures for incubation at 37 and 25 °C, respectively, enhances recovery of the microorganisms. General Considerations A. Epidemiology. Conditions that are associated with increased risk for Yersinia spp. infections (yersiniosis) include iron overload states (such as in patients who receive chronic blood transfusions or those with hemochromatosis) and the use of desferrioxamine, a bacterial siderophore. Infections caused by Y …

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Tularemia

Essentials of Diagnosis • Suspected in patients with fever, lymphadenopathy, and skin lesions who have a history of animal exposure (including to wild animals, ticks, or deerflies) or are coming from a high prevalence area or in laboratory personnel who work with Francisella spp. • Blood culture or other biologic specimen cultures on appropriate culture media. • Serum antibody titer = 1:160 or a fourfold increase or decrease in titer. General Considerations Francisella tularensis is the causative agent of tularemia (also called rabbit fever or deerfly fever), an infectious disease that occurs primarily in animals. It may occasionally cause human disease, which most often manifests itself by one or more skin …

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Neisseria Meningitidis

Essentials of Diagnosis • Transmission in crowded or closed populations. • Meningitis most common, but bacteremia, pneumonia, and other syndromes can occur in absence of meningitis. • Disease often associated with petecchial or purpuric rash, which may involve palms and soles. • Neutrophil-predominant cell profile in CSF, with low-glucose and high-protein concentrations. • Gram-negative diplococci inside neutrophils on stained smears of CSF and aspirated skin lesions. • Fastidious organism requires special media and growth conditions. • Blood and CSF most useful specimens for recovery of organism. • Improved sensitivity of detection with PCR in CSF, but not widely available. General Considerations A. Epidemiology. N meningitidis is found only in humans and …

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Gram-Positive Aerobic Bacilli

LISTERIA MONOCYTOGENES Essentials of Diagnosis • Incriminated foods include unpasteurized milk, soft cheeses, undercooked poultry, and unwashed raw vegetables. • Asymptomatic fecal and vaginal carriage can result in sporadic neonatal disease from transplacental and ascending routes of infection. • Incubation period for foodborne transmission is 21 days. • Organism causes disease especially in neonates, pregnant women, immunocompromised hosts, and elderly. • Organism is grown from blood, cerebrospinal fluid (CSF), meconium, gastric washings, placenta, amniotic fluid, and other infected sites. General Considerations A. Epidemiology. L monocytogenes is found in soil, fertilizer, sewage, and stream water; on plants; and in the intestinal tracts of many mammals. It is a foodborne pathogen that causes …

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Diphtheria

Essentials of Diagnosis • Mildly painful tonsillitis/pharyngitis with associated membrane, cervical adenopathy, and signs of systemic toxicity; “bull neck” appearance. • Hoarseness and stridor. • Palatal paralysis. General Considerations A. Epidemiology. Humans are the only known natural hosts for C diphtheriae, the organism that causes diphtheria. This organism is usually spread via upper respiratory tract droplets, but it can also be spread by direct contact with skin lesions. Transmission appears to be more common when people are living indoors in crowded conditions. Disease is transmitted by those incubating the disease, those convalescing from infection, and also healthy carriers. The organism itself can survive for = 6 months in dust, which may …

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Streptococcus Dysgalactiae Subspp. Equisilimis & Streptococcus Zooepidemicus:Clinical Syndromes

1. PHARYNGITIS The symptoms of pharyngitis caused by these organisms mimic those of S pyogenes pharyngitis (Box 50-1; see also site). Poststreptococcal glomerulonephritis has been described following S dysgalactiae subspp. equisimilis and S zooepidemicus pharyngitis. Notably, however, no antistreptolysin O antibody response will be detected as these organisms do not produce streptolysin O. S dysgalactiae subspp. equisimilis pharyngitis has been associated with sterile reactive arthritis. Acute rheumatic fever, however, has not been described in association with S dysgalactiae subspp. equisimilis and S zooepidemicus pharyngitis. 2. SKIN & SOFT TISSUE INFECTIONS Cellulitis, wound infections, pyoderma, erysipelas, impetigo, and cutaneous ulcers can be caused by these organisms (see site). Breaches in skin integrity …

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