Acinetobacter is a group of bacteria commonly found in soil, sewage and water. It has been identified in natural surface water, groundwater drinking-water and distribution systems. Healthy people can also carry Acinetobacter bacteria on their skin, particularly if they work in a healthcare setting. It can survive for a long time on dry surfaces, making it difficult to eliminate. They are usually harmless organisms, but they occasionally cause infections, predominantly in patients in hospitals.
There are more than 50 species of the Acinetobacter bacteria. Acinetobacter baumannii is the species that causes approximately 80% of reported Acinetobacter infections in humans.
They are opportunistic pathogens that may cause biofilms and urinary tract infections, pneumonia, bacteraemia, secondary meningitis and wound infections. These diseases are predisposed by factors such as malignancy, burns, major surgery and weakened immune systems, such as in neonates and elderly individuals.
These bacteria can have a built-in resistance factor enabling them to be resistant to antibiotics like carbapenems and penicillins. The emergence and rapid spread of multi drug resistant Acinetobacter baumannii is of concern in health care facilities.
In patients with Acinetobacter bacteraemia, intravenous catheters, water baths and room humidifiers have also been identified as a source of infection. Ingestion is not a usual source of infection.
Significance in drinking-water
While Acinetobacter species are often detected in treated drinking-water supplies, there is no evidence of gut infection through ingestion of Acinetobacter species in drinking-water among the general population. However, transmission of non-gut infections by drinking-water may be possible in susceptible individuals, particularly in settings such as health care facilities and hospitals.
Acinetobacter species are sensitive to disinfectants such as chlorine, and numbers will be low in the presence of a residual disinfectant. Control measures that can limit growth of the bacteria in distribution systems include treatment to optimise organic carbon removal, restriction of the residence time of water in distribution systems and maintenance of residual disinfectant.
Research has shown that reduced mobility in patients, Proteus mirabilis colonisation and diabetes mellitus are important risk factors for colonisation with multi-drug resistant Acinetobacter baumannii in high-risk nursing home residents (Mody et al., 2015).
Further reading on Acineteobacter species
Mody L, Gibson KE, Horcher A, Prenovost K, McNamara SE, Foxman B, Kaye KS, Bradley S. Prevalence of and risk factors for multidrug-resistant Acinetobacter baumannii colonization among high-risk nursing home residents. Infect Control Hosp Epidemiol. 2015 Oct;36(10):1155-62. https://doi.org/10.1017/ice.2015.143.
World Health Organisation fact sheet.
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