Acinetobacter calcoaceticus
Acinetobacter calcoaceticus is a nonfermenting, Gram-negative, aerobic coccobacilli,
belonging to the genus of bacteria known as Acinetobacter and to the Moraxellaceae
family. The genus Acinetobacter includes more than 50 species [1].
Together with the species A. baumannii, A. dijkshoorniae, A. nosocomialis, A. pittii and A. seifertii, A. calcoaceticus forms part of the so-called Acinetobacter-calcoaceticus-A.- baumannii complex (the ACB complex). The species that make up the ACB complex are more closely related than other species of Acinetobacter and are phenotypically very similar [2].
It is not usually possible to differentiate between the individual species using routine identification programs [3]. In cases where Acinetobacter calcoaceticus is detected, it is not possible to rule out confusion with the clinically most important representative of the ACB complex, A. baumannii [2][3].
Acinetobacter calcoaceticus has only rarely been isolated from human clinical specimens (e.g. sputum). Its involvement in clinical infections therefore remains unclear.
The clinical pictures relate to cases of:
A. calcoaceticus is an environmental pathogen found primarily in soil and water. The bacterium has also been detected in wastewater and on human skin, as well as on animals and vegetables [7].
Relevance of pathogen in transmission in endoscopy
Gastroenterology: Not relevant
Pulmonology: Low
Ear, nose, and throat: Not relevant
Urology: Not relevant
Relevance for endoscope surveillance
High concern organism
Transmission route
Transmission occurs through direct or indirect contact, e.g. via contaminated materials
and objects, as well as via the hands of medical professionals [4][5].
Resistance to antibiotics
The individual species of the A. calcoaceticus-A. baumannii complex (ACB) are difficult to distinguish from one another based on their phenotypic characteristics. A. calcoaceticus can usually be ruled out when resistance patterns are investigated [6]. Two studies conducted in China have identified clinical isolates with the resistance gene blaNDM-1 on plasmids [6][8]. This gene enables the production of the New Delhi metallo-betalactamase (NDM-1) enzyme, which inactivates antibiotics of the carbapenem class. The resistance gene can be transferred to other species and contribute to the further spread of antibiotic-resistant strains of bacteria.
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