10 Most Resistant Species of Bacteria in the World

Bacteria are capable of surviving in environments where any other form of life would instantly die. Let’s look at some of the most incredible.



This bacterium causes more than 700 million infections worldwide each year and has a 25% mortality rate in the most severe cases. Once you have an infection with these bacteria, it can trigger a host of other illnesses such as a sore throat, impetigo (skin infection) even scarlet fever. Luckily, the bacterium is sensitive to penicillin and is easily treated in most cases. However, new strains are becoming resistant to other types of antibiotics.



Gonorrhea, a sexually transmitted infection, causes several problems in both men and women. This type of bacteria has been showing mutations for over 50 years, slowly adapting to different medical approaches, as other antibiotics were applied to fight the disease. This bacterium has tiny hairs called “pili”, which act as hooks with force 100,000 times greater than their weight. With this strength, the pili can move the infected cell and attach it to other healthy cells, making the treatment even more time-consuming and complicated.



Tuberculosis has been known by several names, such as scrofula and white plague. It is also known for death and destruction throughout history. It is believed that Nefertiti and her husband, Pharaoh Akhenaten died of tuberculosis around 1330 BC, where documents from Ancient Egypt that talk about the dangers of the disease have been found. Although cases have decreased considerably throughout history, its resistance to antibiotics increased in the early 1990s. According to the World Health Organization (WHO), tuberculosis is also the leading cause of death related to bacterial and the leading cause of death among people with HIV.



This superbug can trigger pneumonia, meningitis, and urinary tract infections. It became very resistant during the Iraq war among wounded soldiers passing through different medical facilities. The bacteria can survive difficult conditions for long periods, making it harder to fight off in weaker patients. As with other bacteria, the best way to fight it is to clean in environments where health care takes place.



This bacteria is harmless while in the human intestine. However, it can cause serious problems when in contact with other organs, leading to foodborne infections, meningitis, and urinary tract infections. High levels of antibiotic resistance have been found in E. coli strains, being a worrying example of bacteria that can cause problems if antibiotics are not used correctly from start to finish.



First, it affects middle-aged and seniors with weaker immune systems is more common in hospitalized patients who need to be hooked up to breathing apparatus, take injections directly into their veins for a long time, or take many treatments with antibiotics in a row. This is known to cause several infections and to be quite resistant to various antibiotics. Due to its high resistance, it is common for doctors to request more specific tests to identify which type of strain is present and how to treat it more effectively.



C. difficile is one of the most present superbugs in hospitals around the world. Its main consequence is a very severe type of diarrhea that spreads quickly and can lead to complications in the colon. A recent outbreak of this bacterium made news in the UK when 13 people died in an Eastbourne hospital, and 17 were treated for the bacterium. Doctors reported that this strain of bacteria produced 20 times more toxins than others and was resistant to various drugs.



Due to its rapid mutation and adaptation to different antibiotic treatments, this bacterium skillfully develops resistance to these drugs. It is described as ‘opportunistic’ because it primarily affects people with compromised immunity, such as patients treated for AIDS, cancer, transplantation, or cystic fibrosis, causing severe complications or even death.



Discovered in 1949, the bacterium causes onions to rot, but it can also be hazardous for humans. Although it responds to treatment with combination antibiotics, there are already cases where the bacteria have high resistance levels and can survive extreme conditions. It can be perilous for those who already have preexisting lung conditions such as cystic fibrosis.



Better known as MRSA, the bacteria is naturally present in the skin. Still, if it invades other body parts, it can cause different infections, such as meningitis and pneumonia. The most recent known case of infection with this bacterium was Arthur Araujo Lula da Silva, only seven years old (grandson of ex-president Luis Inácio Lula da Silva). He ended up dying hours after being admitted to the hospital. In the 1960s, 80% of MRSA samples were resistant to antibiotics. 

Methicillin is an antibiotic generally effective in the treatment of this bacteria. However, there are already strains resistant to this type and almost all beta-lactam antibiotics; this class includes penicillins (oxacillin, methicillin) and cephalosporins.


So, these were the top ten most resistant bacteria in the world. Do you know more bacteria? Let us know in the comment section below!

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