Cockroaches are quickly evolving to be resistant to pesticides and could soon be impossible to kill with chemicals alone, according to a new study.

Researchers from Purdue University found that some German roaches, which are one of the most common types of cockroach in the UK, could pass down their resistant genes to their offspring. The findings were published in the journal of Scientific Reports.

The study’s co-author Michael Scharf said: “We didn’t have a clue that something like that could happen this fast.”

“Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.”

The bugs are so dangerous because they are carriers of dozens of bacteria, including E. coli and salmonella, which can make people very sick.

They leave behind feces, saliva and body parts that can trigger asthma and allergies or even cause children to develop these issues.

German cockroaches can be found throughout the world wherever humans live and a single female cockroach can produce dozens of offspring every few months, which can quickly replenish a depleted population.

During the study, the researchers tested three different types of insecticides on cockroach populations in apartment buildings across the US.

They did this for a six-month period and found that the number of cockroaches either remained stable or actually increased.

The problem was found to get worse in the areas where a number of different insecticides were used due to the bugs developing cross-resistance.

Cockroach offspring were resistant to the insecticide that their parents had been resistant to and showed signs of being resistant to other chemicals that they haven’t even encountered yet.

Using a single pesticide on the cockroaches was found to be the most effective method but it was by no means 100% effective.

The researchers think that future methods to control the pests will have to involve increased hygiene, traps or even vacuums.

Scharf noted: “Some of these methods are more expensive than using only insecticides, but if those insecticides aren’t going to control or eliminate a population, you’re just throwing money away.”