Monday, August 20, 2007
Q Fever
Q Fever
Klin Mikrobiol Infekc Lek. 2007 Jun
[Article in Slovak]
Kalinová Z, Dorko E, Cisláková L.
Clinic of Infectious Diseases, Medical Faculty Košice; Slovak Republic, kalinovz@pobox.sk.
Coxiella burnetii, the causative agent of Q fever, is a Gram negative coccobacillus. It resides and replicates in the host s monocytes and macrophages. The developmental cycle of C. burnetii includes macrocellular and microcellular forms and the formation of spore-like bodies. It undergoes a phase variation of outer cell surface antigens from virulent phase I to avirulent phase II after passaging in the yolk sac of embryonated chicken eggs or in cell cultures. C. burnetii belongs to the most resistant bacteria. The main reservoirs of C. burnetii are cattle, sheep and goats. Human Q fever usually results from inhalation of contaminated aerosols. Acute infection mostly takes the course of a flu-like disease, atypical pneumonia or hepatitis, the chronic form resembles endocarditis. Laboratory examinations are based on the presence of antibodies. The drugs of choice are broad-spectrum antibiotics.
PubMed
---
Coxiella burnetii infection.
Ann N Y Acad Sci. 2005 Dec;
Kazar J.
Research Base of the Slovak Medical University, Bratislava, Slovak Republic. jan.kazar@szu.sk
Coxiella burnetii is an obligate intracellular bacterium that causes a worldwide zoonosis, Q fever, and can be misused as a biological warfare agent. Infection in animals (coxiellosis) is mostly persistent. Infection in humans is often asymptomatic, but it can manifest as an acute disease (usually a self-limited flu-like illness, pneumonia, or hepatitis) or as a chronic form (mainly endocarditis, but also hepatitis and chronic fatigue syndrome). C. burnetii infection in pregnant women may result in abortions, premature deliveries, and stillbirths. Infection in nature is maintained and transmitted by ticks as the principal vector and reservoir. Cattle, sheep, and goats are the most important source of human infections. Humans contract C. burnetii infection mostly by aerosol in contact with contaminated environs, wind playing an important factor in spreading the infection. The wide distribution of C. burnetii contributes to a high resistance of its extracellular small cell variant to environmental conditions. Its intracellular large cell variant, adapted to survive under harsh conditions of phagolysosomes, enables long-term survival and persistence of C. burnetii, namely in monocytes/macrophages. Host factors such as underlying disease and cell-mediated immunity play a decisive role in the clinical expression of C. burnetii infection. Complete genome analysis of C. burnetii will certainly contribute to better understanding of the pathogenesis of C. burnetii infection and will improve Q fever diagnosis and immunoprophylaxis.
New York Academy of Sciences
PMID: 17703401 [PubMed - as supplied by publisher]
Klin Mikrobiol Infekc Lek. 2007 Jun
[Article in Slovak]
Kalinová Z, Dorko E, Cisláková L.
Clinic of Infectious Diseases, Medical Faculty Košice; Slovak Republic, kalinovz@pobox.sk.
Coxiella burnetii, the causative agent of Q fever, is a Gram negative coccobacillus. It resides and replicates in the host s monocytes and macrophages. The developmental cycle of C. burnetii includes macrocellular and microcellular forms and the formation of spore-like bodies. It undergoes a phase variation of outer cell surface antigens from virulent phase I to avirulent phase II after passaging in the yolk sac of embryonated chicken eggs or in cell cultures. C. burnetii belongs to the most resistant bacteria. The main reservoirs of C. burnetii are cattle, sheep and goats. Human Q fever usually results from inhalation of contaminated aerosols. Acute infection mostly takes the course of a flu-like disease, atypical pneumonia or hepatitis, the chronic form resembles endocarditis. Laboratory examinations are based on the presence of antibodies. The drugs of choice are broad-spectrum antibiotics.
PubMed
---
Coxiella burnetii infection.
Ann N Y Acad Sci. 2005 Dec;
Kazar J.
Research Base of the Slovak Medical University, Bratislava, Slovak Republic. jan.kazar@szu.sk
Coxiella burnetii is an obligate intracellular bacterium that causes a worldwide zoonosis, Q fever, and can be misused as a biological warfare agent. Infection in animals (coxiellosis) is mostly persistent. Infection in humans is often asymptomatic, but it can manifest as an acute disease (usually a self-limited flu-like illness, pneumonia, or hepatitis) or as a chronic form (mainly endocarditis, but also hepatitis and chronic fatigue syndrome). C. burnetii infection in pregnant women may result in abortions, premature deliveries, and stillbirths. Infection in nature is maintained and transmitted by ticks as the principal vector and reservoir. Cattle, sheep, and goats are the most important source of human infections. Humans contract C. burnetii infection mostly by aerosol in contact with contaminated environs, wind playing an important factor in spreading the infection. The wide distribution of C. burnetii contributes to a high resistance of its extracellular small cell variant to environmental conditions. Its intracellular large cell variant, adapted to survive under harsh conditions of phagolysosomes, enables long-term survival and persistence of C. burnetii, namely in monocytes/macrophages. Host factors such as underlying disease and cell-mediated immunity play a decisive role in the clinical expression of C. burnetii infection. Complete genome analysis of C. burnetii will certainly contribute to better understanding of the pathogenesis of C. burnetii infection and will improve Q fever diagnosis and immunoprophylaxis.
New York Academy of Sciences
PMID: 17703401 [PubMed - as supplied by publisher]
Labels: C. burnetii infection, Coxiella burnetii, Gram negative coccobacillus, q fever
# posted by Pat O'Connor @ 10:06 AM
Friday, August 03, 2007
Enterococci and streptococci
Enterococci and streptococci
Int J Antimicrob Agents. 2007 May
Amyes SG.
Centre for Infectious Diseases, College of Medicine and Veterinary Medicine, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK. s.g.b.amyes@ed.ac.uk
Besides Staphylococcus aureus, other Gram-positive bacteria have become multidrug-resistant and cause therapeutic problems, particularly amongst hospitalised patients. The acquisition of vancomycin resistance by strains of Enterococcus faecium and Enterococcus faecalis is of particular concern and has resulted in treatment failures. Some of the infections caused by these bacteria do respond to treatment with new antibiotics that have been released in the last few years, however more options are required as not all enterococci are inherently susceptible and resistance is beginning to emerge amongst those that were susceptible. Resistance to commonly used antibiotics is also emerging in Streptococcus spp., particularly to the tetracyclines and macrolides. In both genera, multiresistant strains spread between patients and between hospitals. In the laboratory, these bacteria show considerable susceptibility to tigecycline, with little propensity to develop resistance, indicating that tigecycline could assume an important role in controlling infections caused by these Gram-positive bacteria.
Int J Antimicrob Agents. 2007 May
Amyes SG.
Centre for Infectious Diseases, College of Medicine and Veterinary Medicine, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK. s.g.b.amyes@ed.ac.uk
Besides Staphylococcus aureus, other Gram-positive bacteria have become multidrug-resistant and cause therapeutic problems, particularly amongst hospitalised patients. The acquisition of vancomycin resistance by strains of Enterococcus faecium and Enterococcus faecalis is of particular concern and has resulted in treatment failures. Some of the infections caused by these bacteria do respond to treatment with new antibiotics that have been released in the last few years, however more options are required as not all enterococci are inherently susceptible and resistance is beginning to emerge amongst those that were susceptible. Resistance to commonly used antibiotics is also emerging in Streptococcus spp., particularly to the tetracyclines and macrolides. In both genera, multiresistant strains spread between patients and between hospitals. In the laboratory, these bacteria show considerable susceptibility to tigecycline, with little propensity to develop resistance, indicating that tigecycline could assume an important role in controlling infections caused by these Gram-positive bacteria.
PMID: 17659211 [PubMed - in process]
Labels: Enterococci, Gram-positive bacteria, streptococci
# posted by Pat O'Connor @ 8:54 AM
