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Questions and Answers
What percentage of blaOXA-48 was found among the extracted plasmids?
What percentage of blaOXA-48 was found among the extracted plasmids?
What is the primary concern with the increasing incidence of colistin-resistant infections?
What is the primary concern with the increasing incidence of colistin-resistant infections?
What is the purpose of antimicrobial stewardship programs?
What is the purpose of antimicrobial stewardship programs?
What is colistin considered for in the treatment of MDR-GNB?
What is colistin considered for in the treatment of MDR-GNB?
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What was the objective of the study regarding colistin resistance in Gaza Strip hospitals?
What was the objective of the study regarding colistin resistance in Gaza Strip hospitals?
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What method was used to test the antimicrobial susceptibility of Enterobacteriaceae isolates?
What method was used to test the antimicrobial susceptibility of Enterobacteriaceae isolates?
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What is the significance of the results of the study?
What is the significance of the results of the study?
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What is the name of the gene that was the most prevalent among the extracted plasmids?
What is the name of the gene that was the most prevalent among the extracted plasmids?
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How many clinical Enterobacteriaceae isolates were obtained for the study?
How many clinical Enterobacteriaceae isolates were obtained for the study?
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What is the name of the bacteria that colistin is often used to treat?
What is the name of the bacteria that colistin is often used to treat?
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Study Notes
Klebsiella pneumoniae
- Gram-negative rods with a large polysaccharide capsule
- Mucoid, lactose-fermenting colonies on MacConkey agar
- Oxidase negative
- Reservoir: human colon and upper respiratory tract
- Transmission: endogenous
- Pathogenesis:
- Capsule impairs phagocytosis
- Endotoxin causes fever, inflammation, and shock (septicemia)
Diseases Caused by Klebsiella pneumoniae
- Pneumonia:
- Community-acquired, most often in older men with chronic lung disease, alcoholism, or diabetes
- Endogenous, assumed to reach lungs by inhalation of respiratory droplets from the upper respiratory tract
- Frequent abscesses make it hard to treat; high fatality rate (40-60%)
- Sputum is thick and bloody (currant jelly) but not foul-smelling
- Urinary tract infection:
- Catheter-related (nosocomial) from fecal contamination of catheters
- Septicemia:
- In immunocompromised patients, may originate from bowel defect or invasion of IV line
- Klebsiella pneumoniae is the second most common gram-negative pathogen associated with various infections, including:
- Urinary tract infection (UTI)
- Pneumonia
- Intra-abdominal infection
- Bloodstream infection (BSI)
- Meningitis
- Pyogenic liver abscess (PLA)
Rhinitis and Rhinoscleroma
- Rhinitis:
- Infection of the nasal epithelium with K. ozaenae can lead to atrophic rhinitis
- Characterized by focal areas of squamous metaplasia, wasting of the mucous gland, and impairment of mucous secretion
- Nasal mucosa looks dry, glazed, and shiny
- Rhinoscleroma:
- Caused by K. rhinoscleromatis
- Begins with symptoms resembling an ordinary cold
- Granulomatous inflammation of the nasal airway leads to the development of tumor-like submucosal masses
- Masses can become large and may close the nares and cause the face to swell
Enterobacter
- Distinguishing features:
- Many features in common with Klebsiella, but variant
- Motility
- Colonies are slightly mucoid
- Reservoir: soil and water, occasionally found in human feces and the respiratory tract
- Disease(s): opportunistic infections of hospital patients, notably of the urinary tract, and an important cause of bacteremia
- Pathogenesis: poorly understood
- Treatment: highly resistant to penicillins and many cephalosporins
Proteus and Related Genera
- Proteus, Providencia, and Morganella
- Distinguishing features:
- Morphological variation, but in agar-grown cultures, the microscopical appearance is much like that of other coliform bacteria
- Strains of Proteus spp. can be differentiated from Morganella spp. and Providencia spp. by their ability to swarm on suitable agar media
- Disease(s):
- Urinary tract infection in children and bacteremia
- Other strains of Proteus and Providencia are isolated from hospital patients, especially in elderly men following surgery or instrumentation
- Complications of urinary tract surgery, septicaemia, and outbreaks of septicaemia, often with meningitis, may occur among newborns in hospitals
Antibiotic Resistance
- Carbapenemase-producing Enterobacteriaceae (CPE) are a major concern
- blaOXA-48 is the most prevalent carbapenemase gene
- Colistin resistance is a growing concern, especially among Enterobacteriaceae isolated from clinical samples
- The emergence of multidrug-resistant (MDR) strains of Enterobacteriaceae and the lack of new antibiotics are worrisome prospects for global health.
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Description
This quiz covers the distinguishing features, reservoir, transmission, and pathogenesis of Klebsiella pneumoniae, a Gram-negative bacterium.
