Spirochaetes, also known as spirochetes, are bacteria that have a distinctive spiral shape. Viewed under magnification, they look like little telephone cords or corkscrews. Bacteria in six different genera are classified as spirochaetes, including the bacteria which cause syphilis, yaws, Lyme disease, and relapsing fever. Many of these bacteria are pathogenic, causing health problems in the humans and animals they infect.
These bacteria all belong to the order Spirochaetales, and they are gram-negative. Like other gram-negative bacteria, spirochaetes have a distinctive cell wall that includes an outer membrane with compounds that can cause inflammation and infection. Some of the earliest antibiotics were developed specifically to treat spirochaetes, most notably syphilis, and these bacteria have been studied extensively since the 1800s.
Although only six genera are considered spirochaetes, these genera are very diverse and quite widespread. Some are extremely difficult to treat, developing resistance to antibiotics very rapidly, and many are found in the tropics, where they sometimes spread unchecked in low income communities, making treatment and containment very difficult. Because many of these bacteria, that the one that causes yaws, primarily affect low-income people, many drug companies are reluctant to invest in developing new treatments, since they may not pay off.
These bacteria generally prefer moist environments. In the wild, they can be found in water, and they also live inside the bodies of a wide assortment of insects. Many spirochaetes are passed from person to person or animal to animal by insects, especially biting insects, which inject them into the bloodstreams of their victims. This can make spirochaetes very difficult to contain in many communities, as insect populations can be very difficult to control without the extensive use of pesticides.
Infections with spirochaetes often create very distinctive symptoms that can be used in diagnosis, although some medical professionals may take blood samples anyway to confirm infection. In the case of those like syphilis, which have developed significant antibiotic resistance, the blood sample may be cultured so that the healthcare provider can determine the best choice of antibiotic to use, bringing relief to the patient as quickly as possible.
People can reduce the risk of infection with spirochaetes by using personal insect sprays in regions where they are endemic, and also by being careful around infected individuals. Direct contact can spread the bacteria in many cases, especially contact between open wounds, sores, or genitalia. If infected, it is important to complete a full course of antibiotic treatment, as partially completed courses can contribute to the development of drug resistance, a very undesirable outcome.