Acinetobacter baumannii

Taxobox
color = lightgrey
name = "Acinetobacter baumannii"


image_width = 300 px
image_caption = "Acinetobacter baumannii"
regnum = Bacteria
phylum = Proteobacteria
classis = Gammaproteobacteria
ordo = Pseudomonadales
familia = Moraxellaceae
genus = "Acinetobacter"
species ="A. baumannii"
binomial = "Acinetobacter baumannii"

"Acinetobacter baumannii" is a species of pathogenic bacteria called aerobic gram-negative bacillus and is naturally sensitive to relatively few antibiotics. A.baumannii forms opportunistic infections.cite book | author = Gerischer U (editor). | title = Acinetobacter Molecular Biology | edition = 1st ed. | publisher = Caister Academic Press | year = 2009 | url=http://www.horizonpress.com/acineto | id = [http://www.horizonpress.com/acineto ISBN 978-1-904455-20-2 ] ] There have been many reports of "A. baumannii" infections among American soldiers wounded in Iraq.cite web|url=http://www.acinetobacter.org/ |title=Acinetobacter baumannii in Iraq|accessdate =2007-02-15 ] Multi-drug resistant Acinetobacter baumannii' is abbreviated as MDRAB. Multidrug-resistant Acinetobacter is not a new phenomenon, but A baumannii has always been inherently resistant to multiple antibiotics.

Biology

:"See also the main article on the Acinetobacter genus""Acinetobacter baumannii" is the most relevant human pathogen within the "Acinetobacter" genus.Most "A. baumannii" isolates are multiresistant, containing in their genome small, isolated islands of alien (meaning transmitted genetically from other organisms) DNA and other cytological and genetic material; this has led to more virulence. "Acinetobacter" have no flagellum; the name is Greek for 'motionless'.cite web
title=Infectious Disease Case Conference |author=Asif Zia
publisher=Wake Forest University| date= 2004-04-19
url =http://www1.wfubmc.edu/medicalcenter/pp/ID/04/040419a.ppt#
accessdate= 2007-10-03]

Transmission and Prevalence

Acinetobacter enters into the body through open wounds, catheters, and breathing tubes. It usually infects those with compromised immune systems, such as the wounded, the elderly, children or those with immune diseases. Colonization poses no threat to people who aren't already ill, but colonized health care workers and hospital visitors can carry the bacteria into neighboring wards and other medical facilities.cite news| url=http://www.wired.com/wired/archive/15.02/enemy_pr.html |publisher=Wired| year=2007|month=February|author=Steve Silberman
title = The Invisible Enemy|accessdate =2007-02-15] The number of nosocomial infections (hospital-acquired infections) caused by "A. baumannii" has increased in recent years.cite web|url=http://www.leishmaniasis.us/Mapping.html
title= Mapping Acinetobacter baumannii from Iraq to Civilian Hospitals
author = The Coalition of the Contaminated
accessdate = 2007-10-03]

The first military outbreaks of severe "A. Baumannii" infections occurred in April, 2003 in American soldiers returning from Iraq. Early reports attributed the infections to the Iraqi soil. Later testing demonstrated widespread contamination of field hospitals as the most plausible vector.

Virulence and Pathogenicity

This opportunistic pathogen causes a wide variety of serious infections in humans, mostly in compromised patients. Recently, "A. baumannii" has emerged as an important pathogen among wounded soldiers, threatening civilian and military patients.

Nosocomial "A. baumannii" bacteremia may cause severe clinical disease that is associated with a high mortality rate of up to 75%. cite journal |author=Cisneros J, Reyes M, Pachón J, Becerril B, Caballero F, García-Garmendía J, Ortiz C, Cobacho A |title=Bacteremia due to Acinetobacter baumannii: epidemiology, clinical findings, and prognostic features |journal=Clin Infect Dis |volume=22 |issue=6 |pages=1026–32 |year=1996 |pmid=8783704|accessdate =2007-02-15] This opportunistic pathogen expresses a myriad of factors that could play a role in human pathogenesis. Among these factors are the attachment to and persistence on solid surfaces, the acquisition of essential nutrients such as iron, the adhesion to epithelial cells and their subsequent killing by apoptosis, and the production and/or secretion of enzymes and toxic products that damage host tissues. However, very little is known about the molecular nature of most of these processes and factors and almost nothing has been shown with regard to their role in bacterial virulence and the pathogenesis of serious infectious diseases. Fortunately, some of these gaps can now be filled by testing appropriate isogenic derivatives in relevant animal models that mimic the infections in humans, particularly the outcome of deadly pneumonia. Such an approach should provide new and relevant information on the virulence traits of this normally underestimated bacterial human pathogen.cite book | author = Gerischer U (editor). | title = Acinetobacter Molecular Biology | edition = 1st ed. | publisher = Caister Academic Press | year = 2008 | url=http://www.horizonpress.com/acineto | id = [http://www.horizonpress.com/acineto ISBN 978-1-904455-20-2 ] ]

Control and Treatment of Infections

Multi-resistant "A. baumannii" infections are currently treated with imipenem and an older class of drugs known as polymyxins. These, along with stricter infection-control measures, such as monitored hand washing, have lowered infection rates in some military hospitals.cite news
author=Jia-Rui Chong | date=2007-10-01 | url = http://www.napavalleyregister.com/articles/2007/10/01/news/national/iq_4145134.txt | publisher = Napa Valley Register
title = The path of war sets doctors on the warpath of disease
accessdate =2007-10-03 ]

MDRAB infections are difficult and costly to treat. A study at a public teaching hospital found that the mean total hospital cost of patients who acquired MDRAB was $98,575 higher than that of control patients who had identical burn severity of illness indices.cite journal
title=Direct costs of multidrug-resistant Acinetobacter baumannii in the burn unit of a public teaching hospital.
journal=|American Journal of Infection Control|volume=32|issue=6|pages=42–344|month=October |year=2004
author=Wilson, Stephen
url=http://pt.wkhealth.com/pt/re/ajic/abstract.00000545-200410000-00005.htm | accessdate=2007-10-03]

References