Most activated sludge treatment plants suffer from the presence of foams on the surfaces of their aeration reactors. These are often stabilized by hydrophobic mycolic acid-synthesizing actinobacterial species. A polyvalent
Siphoviridaephage, GTE7, which lysed several Gordoniaand Nocardiaspecies, is described here. Its genome has a modular structure similar to that described for Rhodococcusphage ReqiDocB7. In laboratory-scale experiments, we showed that GTE7 prevents stabilization of foams by these Gordoniaand Nocardiaspecies.