Tags: Piperacillin-Tazobactam

Important Anaerobes

Essentials of Diagnosis • Foul odor of draining purulence. • Presence of gas in tissues. • No organism growth on aerobic culture media. • Infection localized in the proximity of mucosal surface. • Presence of septic thrombophlebitis. • Tissue necrosis and abscess formation. • Association with malignancies (especially intestinal). • Mixed organism morphologies on Gram stain. General Considerations A. Epidemiology and Ecology. Anaerobic bacteria are the predominant component of the normal microbial flora of the human body. The following sites harbor the vast majority of them: • Skin: Mostly gram-positive bacilli such as Propionibacterium acnes • Gastrointestinal tract: In the oral cavity Prevotella spp., Porphyromonas spp., Peptostreptococcus spp., microaerophillic streptococci, and …

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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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Other Pseudomonas Species of Medical Importance

P PSEUDOMALLEI MELIOIDOSIS This organism is endemic in Southeast Asia with the highest prevalence in Thailand. The organism is a saprophyte living in the soil. Infection may be subclinical, acute, subacute, or chronic. Pulmonary infection is most common. Histologically, the acute illness is represented by lung abscesses and the subacute form by caseation necrosis. Upper lobe cavities must be distinguished from those caused by tuberculosis. Debilitated patients may develop hematogenous spread of the organism to other organs. Skin lesions from direct inoculation cause suppurative lesions often in association with nodular lymphangitis and regional lymphadenopathy. Diagnosis is made in a patient from an endemic area with a compatible clinical illness who has …

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Deciding On Hospital Admission In Acute Pneumonia

The Pneumonia Patient Outcome Research Team developed useful criteria called the pneumonia severity index for assessing pneumonia severity; however, that index proved to be complex and difficult to use. A simpler index called the CURB-65 (confusion, urea nitrogen, respiratory rate, blood pressure, age 65 years or older) has been shown to have sensitivity and specificity nearly equal to that of the pneumonia severity index. Both indexes can be used to guide decisions on admission to a hospital ward or intensive care unit. As shown in Figure 4.5, patients with a score of 0 or 1 can be treated as outpatients; those with a score of 2 or more warrant hospitalization. A …

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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 Therapy

Despite dire warnings that we are approaching the end of the antibiotic era, the incidence of antibiotic-resistant bacteria continues to rise. The proportions of penicillin-resistant Streptococcus pneumoniae, hospital-acquired methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus strains continue to increase. Community-acquired methicillin-resistant Staphylococcus aureus is now common throughout the world. Multiresistant Acinetobacter and Pseudomonas are everyday realities in many of our hospitals. The press is now warning the lay public of the existence of “dirty hospitals.” As never before, it is critical that health care providers understand the principles of proper anti-infective therapy and use anti-infective agents judiciously. These agents need to be reserved for treatable infections — not used to calm the …

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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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Urinary Tract Infections and Prostatitis

Definition Infections of the urinary tract represent a wide variety of clinical syndromes including urethritis, cystitis, prostatitis, and pyelonephritis. A urinary tract infection is defined as the presence of microorganisms in the urine that cannot be accounted for by contamination. The organisms have the potential to invade the tissues of the urinary tract and adjacent structures. Lower tract infections include cystitis (bladder), urethritis (urethra), prostatitis (prostate gland), and epididymitis. Upper tract infections involve the kidney and are referred to as pyelonephritis. Uncomplicated urinary tract infections are not associated with structural or neurologic abnormalities that may interfere with the normal flow of urine or the voiding mechanism. Complicated urinary tract infections are …

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Respiratory Tract Infections, Lower

Lower respiratory tract infections include infectious processes of the lungs and bronchi, pneumonia, bronchitis, bronchiolitis, and lung abscess. Bronchitis Acute bronchitis Bronchitis refers to an inflammatory condition of the large elements of the tracheobronchial tree that is usually associated with a generalized respiratory infection. The inflammatory process does not extend to include the alveoli. The disease entity is frequently classified as either acute or chronic. Acute bronchitis most commonly occurs during the winter months. Cold, damp climates and/or the presence of high concentrations of irritating substances such as air pollution or cigarette smoke may precipitate attacks. Pathophysiology Respiratory viruses are by far the most common infectious agents associated with acute bronchitis. …

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