Infections from the sea may be from coral cuts and abrasions, or venomous or non-venomous animal spine penetration and exposure to sea or fresh water. The infecting organisms can be either human skin bacteria or specific fish or marine or fresh/brackish water bacteria. The specific bacteria live in various environments, often including the mucous layer of the skin of fish. Most of the zoonotic bacteria are also fish pathogens. Bacterial populations and risk of infection to both fish and humans are increased by pollution in waterways/estuaries. Specialised laboratory culture techniques should be requested if specific pathogens are suspected. The common human skin pathogens are Streptococcus pyogenes (especially common in tropical areas, e.g. northern Australia) and Staphylococcus aureus.