Nasal bacterial culture. Coloured scanning electron micrograph (SEM) of a culture of bacteria from a nasal passage. Our noses, sinuses and nasal passages contain colonies of beneficial bacteria but, primarily due to overuse of antibiotics, we have changed the colonies in our noses to bacteria that are more harmful. Among these are bacteria such Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus sp., that lead to some of the common sinusitis and throat infections that regularly plague people. Magnification: x15000 when printed at 10cm wide