Tags: Peritonitis

Intestinal Nematode Infections

ASCARIASIS Worldwide, more than 1 billion people are infested with Ascaris lumbricoides, the causative agent of ascariasis or roundworm. More than 4 million people are estimated to be infected in the United States. Infection occurs predominately in the southeastern states and more commonly in younger children, and it is associated with lower socioeconomic status. The organism is acquired through ingestion of embryonic forms of the worm, which are found in fecally contaminated soil. After ingestion, the embryonic eggs hatch in the small intestine, and the larvae undergo a tissue migration phase. During the migration, the larvae penetrate the intestinal wall and travel intravenously to the pulmonary alveoli. In the lungs, the …

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Cryptosporidium, Cyclospora, & Isospora Species & Microsporidia

Within the last decade, the AIDS epidemic has heightened awareness of several gastrointestinal spore-forming protozoan pathogens. The genera Cryptosporidium, Isospora, and Cyclospora are members of the subclass Coccidia and phylum Apicomplexa; the microsporidia are a group of organisms belonging to the phylum Microspora. The spectrum of disease caused by these protozoans goes beyond gastrointestinal manifestations, and the significance of these protozoan infections is becoming increasingly appreciated in both immunocompromised and immunocompetent hosts. CRYPTOSPORIDIUM Essentials of Diagnosis • Key signs and symptoms include dehydration with watery diarrhea of variable quantity. • Waterborne transmission is the most common mode of oocyst transmission. • Patients at risk for person-to-person transmission include household contacts, sexual …

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Intestinal Disease

Clinical Findings A. Signs and Symptoms. Of patients infected with E histolytica, > 90% are asymptomatic carriers who are colonized with the organism and pass cysts in the stool. This carrier state often resolves without treatment, although relapses and reinfection are common. Acute amebic colitis usually presents with several weeks of lower abdominal pain and diarrhea with frequent loose to watery stools containing blood and mucus. Most patients are afebrile. Significant volume depletion is uncommon. Chronic amebic colitis is characterized by low-grade inflammation resulting in intermittent bloody diarrhea and abdominal pain over a period of months to years. It is often difficult to distinguish chronic disease from inflammatory bowel disease, and …

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Penicillium Infections

Essentials of Diagnosis Penicillium marneffei infection found in both immunocompetent and immunosuppressed patients. P marneffei found in Southeast Asia and southern China. Mold, septate hyphae 1.5-5 um in diameter. May be cultured from a variety of specimens including blood. Penicillium spp. other than P marneffei occur worldwide. Infection with Penicillium spp. is rare; occurs in immunosuppressed patients. General Considerations A. Epidemiology. Penicillium spp. are ubiquitous in nature and may be recovered with ease from a variety of sources within the hospital environment. These molds commonly contaminate clinical specimens and cause contamination in the laboratory. Colonization of nonsterile anatomical sites in humans is common. In most cases where Penicillium spp. are recovered …

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Candida Species

Essentials of Diagnosis Characteristic appearance of yeast and hyphae on KOH preparations. Formation of germ tubes in serum is presumptive diagnosis for Candida albicans. Cultures must be interpreted with caution because positive culture may represent colonization rather than infection. Serology not useful. General Considerations A. Epidemiology. Candida organisms are commensal with humans and, in the absence of alterations in host defense mechanisms, usually do not cause disease. Candida exists as normal flora within the oral cavity, throughout the gastrointestinal (GI) tract, in expectorated sputum, in the vagina, and in the bladder of patients with indwelling catheters. There are >150 species within the genus Candida, although the majority are not known to …

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Chlamydia Trachomatis Infections

Essentials of Diagnosis Typical intracytoplasmic inclusions in Giemsa-stained cell scrapings from the conjunctiva. Ligase chain reaction (LCR) or polymerase chain reaction (PCR) in first-void urine. Positive culture in McCoy or HeLa cells of body fluids or secretions. Positive microimmunofluorescence serology for suspected cases of lymphogranuloma venereum and infants with pneumonia. Complement fixation titer of 1:64 or greater in patients with presumed lymphogranuloma venereum. Clinical Syndromes C trachomatis is associated with urethritis, proctitis, conjunctivitis, and arthritis in women and men; epididymitis in men; and mucopurulent cervicitis (MPC), acute salpingitis, bartholinitis, and the Fitz-Hugh and Curtis syndrome in women (Box 1). C trachomatis and Neisseria gonorrhoeae (see site) coinfections are common in women …

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Mycoplasma & Ureaplasma

Mycoplasma and Ureaplasma species (mycoplasmas) are ubiquitous in nature and are commonly found in plants, animals, and humans. These bacteria contain the smallest amount of double-stranded DNA that is capable of producing a free-living microorganism; they measure between 0.15 and 0.3 um in diameter and = 2 um in length. They are believed to have evolved from a putative common ancestor of the gram-positive bacteria by a process of genome reduction and adoption of a dependent, parasitic life style. Mycoplasma and Ureaplasma spp. lack a cell wall. Therefore, they cannot be visualized with the Gram stain and are not susceptible to antibiotics that act on cell wall synthesis (eg, penicillins and …

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Other Mycobacteria

Essentials of Diagnosis Demonstration of the acid-fast bacillus. Infections more common in immunocompromised hosts. Infections mainly pulmonary or soft tissue. General Considerations The increasingly relative importance of the atypical mycobacteria, many of which are ubiquitous in the environment, was recognized with the decline in tuberculous disease. Generally, atypical mycobacteria are unusual causes of disease in patients who are immunocompetent but can in immunocompromised hosts such as AIDS and cancer patients. Most infections caused by atypical mycobacteria are skin and soft tissue abscesses, sometimes following pulmonary infection or implantation of prosthetic devices. There have been a few reports of epidemics of iatrogenic infection with atypical mycobacteria, associated with injection of contaminated materials. …

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Mycobacterium Avium Complex (Disseminated & Pulmonary Disease)

Mavium is the most common atypical mycobacterium to cause disease in humans. In immunocompetent patients, M avium can cause pulmonary disease (Box 1). It is the most common pulmonary pathogen of all the atypical mycobacteria. There are several risk factors for pulmonary M avium infection besides AIDS. Patients with underlying pulmonary disease, those who have had a gastrectomy, and those with cystic fibrosis can develop pulmonary infection. Pulmonary disease can also develop in a subgroup of women without pulmonary disease but with mitral valve prolapse, pectus excavatum, and thoracic scoliosis. In immunocompromised patients such as those with AIDS who have a CD4 lymphocyte count of < 100, M avium can cause …

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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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