Flies in hospitals may pose a greater threat than a buzzing annoyance. A study published Friday found almost 9 out of 10 flying insects collected from seven hospitals in England carried potentially harmful bacteria on or in their bodies.

Over half of the bacterial strains identified were 'superbugs,' meaning they were resistant to at least one class of antibiotic, with almost 20 percent resistant to multiples classes of antibiotics. Penicillin was the least effective antibiotic against the bacteria that was found.

Read more at Science Alert.