7 Deadliest Bacteria on Earth

E. Coli

Bacteria are the pathogens that cause deadly illness and disease in their human hosts. Millions of people every year die because of these tiny living beings that multiply in our system and take advantage of any weaknesses they find. Defining “deadly bacteria” is difficult because there are many factors, including do you look at what has killed the most in history, or the bacteria that is fatal without treatment but made innocuous with treatment? That said, here are some amazing photographs of deadly bacteria in our world.

7) Salmonella


Salmonella is deadly in two forms, both the enterica and the typhi. Salmonella typhi causes typhoid fever, which is responsible for the death of 216,000 persons a year in endemic areas. It is spread through feces and urine contamination. Some people are asymptomatic carriers like the famous typhoid patient Mary who was responsible for infecting 53 people and died in quarantine as the first asymptomatic carrier ever to be quarantined in the U.S.

Image: microrao

6) Tetanus


The good news about the tetanus bacteria is the development of a vaccine against it. For those who may have forgotten to get the vaccine – if you are injured where dirt-carrying spores might enter your system, the vaccine can be given then. Lockjaw and terrible spasms are the symptoms of the disease, and a good ICU is needed to have a chance at recovery.

In modern cities, it is no longer the problem it used to be, but there are still 58,000 babies who die from it yearly in the world and numerous adults who are disabled by it or die from it. Some patients are paralyzed with curare to stop the bone-breaking spasms when necessary.


5) Staphylococcus


Staphylococcus is one of the largest groups of bacteria with 40 subspecies. It is normally found in small amounts on your skin, and a normal immune system can deal with it or antibiotics in most cases if the bacteria takes a hold and makes someone ill. Recently, however, antibiotic-resistant strains have appeared, called MRSA (multidrug-resistant Staphylococcus aureus), which is probably best known for causing the ‘flesh eating disease’.

In an ironic turn to old medicine considering this strain developed because of overuse of antibiotics, along with vancomycin, maggot therapy has proven to be of use in treating necrotizing fasciitis. If affected, the maggots will eat all the dead and gangrenous tissue, leaving healthy live tissue behind, but unfortunately, there are many cases where nothing but wholesale amputations or the removal of organs will safe the life of the patient.

Image: Nephron


4) Syphilis


Syphilis is included here because in history, it was one of the most debilitating diseases, often called the “great imitator”. Very difficult to diagnose, the genital sores imitated other disease as did other symptoms. Easily treatable in the first and second stages now, the tertiary stage is still a big problem. This is when the bacteria often invade the brain, leading to generalized paresis.

Syphilis can also affect the heart and its main aorta, leading to a bobbing of the head in rhythm to the heartbeat, often ending in death. It is hard to describe the effects in words – if you look at source number two, you will find some pictures that show the devastation the disease wreaks.

3) Streptococcus

Streptococcus pneumoniae

This killer is responsible for numerous cases of pneumonia throughout the world, and equally as important, is the main cause of bacterial meningitis, a killer in its own right. The body has a normal amount of this flora in its respiratory system but when the immune system is compromised or something occurs to disrupt it, this transforms into a virulent bacteria capable of killing those affected.


2) Tuberculosis

Mycobacterium tuberculosis

Tuberculosis has ravaged the world for centuries, also known as consumption. It has been found in the spines of mummies and “in 2007 there were an estimated 13.7 million chronic active cases, 9.3 million new cases, and 1.8 million deaths, mostly in developing countries” according to the WHO. The organization has started a program that aims at saving 14 million lives between 2006 and 2015. There is no effective vaccine as yet and the disease often lies dormant for years in the respiratory system before being activated.

1) E. Coli

E. Coli

According to Wikipedia, “virulent strains of E. coli can cause gastroenteritis, urinary tract infections, and neonatal meningitis. In rarer cases, virulent strains are also responsible for hæmolytic-uremic syndrome (HUS), peritonitis, mastitis, septicemia and Gram-negative pneumonia.” Needless to say, this one little bacteria can cause havoc in our bodies.

It is one of the most commonly involved in product recalls as well. On the bright side, in developed countries, it is easily treated at the moment with antibiotics; unfortunately, it also quickly grows resistant, so combination therapies may be chosen. E. coli is not one of the devastating killers as a whole but deadly in areas without antibiotics or treatment.

The world is populated with bacteria that are good for us and then we have the few bad apples. As we have seen, treatment is often available when the bacteria is caught early on or if you live in a developed country. Unfortunately, that is not the case for millions of people.

Sources: 1,2, 3, 4, 5