Some strains produce acid from D-glucose, D-ribose, D-xylose, and L-arabinose utilized oxidatively as carbon sources. These and other phenotypic characters are incorporated in various commercial identification systems e. Many of these infections involve multidrug-resistant MDR strains, and occur in intensive care or high-dependency units in which severely-ill or debilitated patients are treated extensively with broad-spectrum antibiotics. In European intensive care units ICUs ,
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Identification[ edit ] Identification of Acinetobacter species is complicated by lack of standard identification techniques. Initially, identification was based on phenotypic characteristics such as growth temperature, colony morphology, growth medium, carbon sources, gelatin hydrolysis, glucose fermentation, among others. This method allowed identification of A.
Closely related species could not be differentiated and individual species such as A. Because routine identification in the clinical microbiology laboratory is not yet possible, Acinetobacter isolates are divided and grouped into three main complexes: Acinetobacter calcoaceticus-baumannii complex: glucose-oxidising nonhemolytic A.
The other reliable identification test at genus level is chromosomal DNA transformation assay. In this assay, a naturally competent tryptophan auxotrophic mutant of Acinetobacter baylyi BD4 trpE27 is transformed with the total DNA of a putative Acinetobacter isolate and the transformation mixture is plated on a brain heart infusion agar. Growth on the AMA indicates a positive transformation assay and confirms the isolate as a member of the genus Acinetobacter.
However, most recent methods include multilocus sequence typing and multilocus PCR and electrospray ionization mass spectrometry, which are based on amplification of highly conserved housekeeping genes and can be used to study the genetic relatedness between different isolates.
It can cause various other infections, including skin and wound infections, bacteremia , and meningitis , but A. Of the Acinetobacter, A. Risk factors include long-term intubation and tracheal or lung aspiration. In most cases of ventilator-associated pneumonia, the equipment used for artificial ventilation such as endotracheal tubes or bronchoscopes serve as the source of infection and result in the colonization of the lower respiratory tract by A.
UTIs caused by A. Though less common, some evidence also links this bacterium to meningitis, most often following invasive surgery, and, in very rare cases, to community-acquired primary meningitis wherein the majority of the victims were children. Resistance to carbapenems is also being increasingly reported. In healthy individuals, Acinetobacter colonies on the skin correlate with low incidence of allergies ;  Acinetobacter is thought to be allergy-protective. Resistance to fluoroquinolones has been reported during therapy, which has also resulted in increased resistance to other drug classes mediated through active drug efflux.
A dramatic increase in antibiotic resistance in Acinetobacter strains has been reported by the Centers for Disease Control and Prevention CDC , and the carbapenems are recognised as the gold-standard and treatment of last resort.
One antimicrobial agent, colistin polymyxin E , has been used to treat infections with multidrug-resistant A. Because A. Reports suggest this bacterium is susceptible to phage therapy. Recipient bacteria must first enter a special physiological state termed competence to receive donor DNA. The DNA taken up may be used to repair DNA damage or as a means to exchange genetic information by horizontal gene transfer.
Acinetobacter may not always produce symptoms. A person can also carry the bacteria in and on their body without it causing any infections. There are more than 50 species of the Acinetobacter bacteria. Acinetobacter calcoaceticus and Acinetobacter lwoffii are two other types of the bacteria that commonly cause infections. Researchers have found the above types of Acinetobacter, as well as a few other types, on vegetables, dairy products, meat, livestock, and human skin. This finding suggests that there are many ways in which humans can come into contact with Acinetobacter bacteria.
Acinetobacter: What to know
What is CDC doing to address Acinetobacter infections? Acinetobacter is a group of bacteria germs commonly found in the environment, like in soil and water. While there are many types, the most common cause of infections is Acinetobacter baumannii, which accounts for most Acinetobacter infections in humans. Acinetobacter baumannii can cause infections in the blood, urinary tract, and lungs pneumonia , or in wounds in other parts of the body. If they develop resistance to the group of antibiotics called carbapenems, they become carbapenem-resistant.