Tags: Streptomycin

Actinomycetes

Actinomycetes are variably acid-fast, gram-positive bacilli that are sometimes filamentous and branched. Originally thought to be fungi due to their hyphae-like appearance, they are now recognized as bacteria based on their cell wall components, reproduction by fission without sporulation or budding, inhibition by antibacterial agents, and molecular phylogenetic analysis. The actinomycete chromosomes contain a high content of guanosine and cytosine. The actinomycetes include the genera Mycobacterium and Corynebacterium, which are discussed in site and site, respectively. The actinomycetes also include the genera Nocardia, Actinomyces, Rhodococcus, Tsukumurella, Gordona, Actinomadura, and Streptomyces, as well as the Whipple’s disease bacillus Tropheryma whippelii. Of these, members of the genus Nocardia are the most significant from …

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Tuberculosis

Essentials of Diagnosis • The cardinal symptoms of tuberculosis (TB) are fatigue, weight loss, fever, and night sweats. • The most commonly infected populations include the homeless, institutionalized patients, and HIV-positive patients. • In most cases, a TB skin test (PPD) is positive. • To establish presence of infection, an acid-fast bacilli (AFB) smear demonstrates the acid-fast bacillus. • In primary pulmonary TB, an infiltrate in the lower lobes of the lung is usually seen on chest x-ray. In contrast, apical lung infiltrates are commonly seen in the reactivation of pulmonary TB. General Considerations Mycobacterium tuberculosis is still an important pathogen. Approximately one-third of the world’s population is infected with M …

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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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Plague

Essentials of Diagnosis • Suspected in patients living in or traveling from an endemic area who have acute onset of fever, prostration, and tender adenopathy. • Yersinia pestis may be recovered from blood cultures or cultures of an aspirate from buboes or sputum in the pneumonic form in 80%-100% of cases. • Gram stains of bubo aspirate or sputum demonstrate the characteristic bipolar “safety pin” gram-negative microorganisms. • Y pestis grows aerobically on most culture media after 48-72 h of incubation. General Considerations The genus Yersinia, named after Alexander Yersin (1863-1943), includes Y pestis, Y enterocolitica, and Y pseudotuberculosis. Y pestis is the cause of plague, a disease that has left …

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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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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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Anthrax

Essentials of Diagnosis • Contact with infected animals, carcasses, hair, wool, or hides from goats, sheep, cattle, swine, horses, buffalo, or deer. • Incubation period lasting 1-7 days, usually 2-5 days, after exposure. • Painless lesion progressing to papule, to vesicle, to necrosis, and to eschar. • Rapid development of chest pain, dyspnea, and circulatory collapse after brief flulike syndrome. • Direct gram-stained smear and/or cultures of lesions or discharges. • Widened mediastinum on chest radiograph in inhalational disease. General Considerations Anthrax is primarily a disease of herbivores, but humans acquire the disease through contact with infected animals or animal products. A. Epidemiology. Historically, anthrax has been an occupational disease of …

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Enterococci

Essentials of Diagnosis • Gram stain shows gram-positive cocci that occur in singles, pairs, and short chains; recovery of microorganism from culture of blood or other sterile source. • Lancefield group D antigen. • Clinical isolates: Enterococcus faecalis, 74%; E faecium, 16%; other species, 10%. • Facultative anaerobes grow in 6.5% NaCl at pH 9.6 and at temperatures ranging from 10 °C to 45 °C, and grow in the presence of 40% bile salts and hydrolyze esculin and L-pyrrolidonyl-ß-naphthylamide. • Infections typically of a gastrointestinal or genitourinary origin. • The most common infections are urinary tract infection, bacteremia, endocarditis, intra-abdominal and pelvic infection, and wound and soft tissue infection. General Considerations …

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Enterococci: Clinical Syndromes

URINARY TRACT INFECTION Urinary tract infections, including uncomplicated cystitis, pyelonephritis, prostatitis, and perinephric abscess, are the most common type of clinical infections produced by enterococci (Box 1). Most enterococcal urinary tract infections are nosocomial and are associated with urinary catheterization or instrumentation. BACTEREMIA & ENDOCARDITIS Nosocomial enterococcal bacteremias are commonly polymicrobial. Portals of entry for enterococcal bacteremia include the urinary tract, intra-abdominal or pelvic sources, wounds (especially burns, decubitus ulcers, and diabetic foot infections), intravascular catheters, and the biliary tree. Metastatic infections other than endocarditis are rare in enterococcal bacteremia. Enterococci account for ~5-10% of all cases of infective endocarditis (see site). Most cases are caused by E faecalis, but E …

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Order Amoxil (Amoxicillin) Without Prescription 500mg

Amoxicillin: A Broad Spectrum Antibiotic Amoxicillin though originally introduced in the early 1970′s for oral use in U.K., has found a gradually regular place as broad spectrum antibacterial to treat the infections of various diseases. Amoxicillin has been found to be more effective against gram positive than gram negative microorganisms and demonstrated greater efficacy to penicillin and penicillin V. Moreover, it has been found comparable to other antibiotics, e.g. ampicillin, azithromycin, clarithromycin, cefuroxime and doxycycline in treatment of various infections / diseases. In the past decade, amoxicillin has been reported to be useful in the management of many indications and is used to treat infections of the middle ear (otitis media) …

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