Hospital infections caused by bacteria resistant to antibiotics are a reason for great worry for international health authorities, and cause several thousand deaths every year worldwide. But now a study by researchers in the Department of Chemistry of the University of Turku, in Finland, may help to deal with this problem more effectively, by combatting in particular one of the “families” of bacteria that is creating major damage, namely Acinetobacter baumannii. These micro-organisms attach themselves firmly to the containers and plastic instruments used during medical procedures, and are more resistant than others to normal disinfectant systems.

But why does this happen? As reported in the scientific journal PNAS, the Finnish researchers have discovered that Acinetobacter baumannii possess a series of “rod-shaped structures”, called pili (similar, in certain aspects, to hair), which have a very archaic form, but are very efficient and different from the similar structures found in other microorganisms. At the tip of these rod-shaped structures there are thin filaments similar to finger-like loops, which attach very well to hydrophobic plastic surfaces (i.e. those that repel water, like polystyrene, polypropylene and polyethylene), but not to hydrophilic surfaces (i.e. those that are partially permeable to water), because these types of plastic do not possess the series of micro-cavities essential to the “pili”.

The research group successfully tested a series of specific antibodies in the laboratory aimed at combatting the “finger-like loops”, but their large-scale use requires time and, in any case, is very costly. On the other hand, an initial effective measure that could be applied immediately – suggest researchers – could be the gradual replacement of hydrophobic plastics with other hydrophilic plastics, in such a way as to pull the rug out from under the acinetobacteria. New antibiotics targeting these unusual pili could also be studied.

Interesting fact: the  Acinetobacter baumannii is also known as “Iraqibacter”, due to its dramatic emergence in the US military hospitals in Iraq, becoming one of the most troublesome pathogens faced in those situations, which were already so complex.