Antibiotic resistant bacteria examples

What Bacteria Cannot Be Treated with Antibiotics?

How Does Antibiotic Resistance Occur?

There are countless numbers of various bacteria, including pathogenic that may cause different infections. The inability to treat those infections just several decades ago caused millions of deaths. Thanks to the development of antibiotics, the world is much safer now, because lots of infections that used to be killing people can be successfully treated today.

Unfortunately, the future of humanity may not be that bright because of antibiotic resistance, which is developing rapidly, making modern, potent antibiotics useless.

Antibiotic resistance means susceptibility of bacteria to antibiotics that are divided into two groups, including bactericidal and bacteriostatic agents. Bactericidal medications destroy bacteria, and bacteriostatic drugs are slowing the reproduction or growth of bacteria. Infection may be impossible to treat if a resistant strain of bacteria becomes dominant in an infection.

Historical Background

The first cases of antibiotic resistance were recognized in the 1940s. It was right after penicillin started to be used massively for the needs related to World War II. It was used for the treatment of wounds and venereal diseases, such as gonorrhea and syphilis.

The cases of resistance to penicillin were found before the war had ended. In 1944, several scientists who worked independently reported the presence of enzyme secreted by certain bacteria that made penicillin ineffective. Today, antibiotic resistance is a global problem because the number of bacteria resisting to the effects of antibiotics is rapidly growing.

How Antibiotic Resistance Occurs

Antibiotic resistance may occur in several ways, but all of them are related to biochemical modifications, changing properties of the bacterial cell so that they can withstand the activities of antibiotics.

The following are the mechanisms of antibiotic resistance:

  • Producing of enzymes inactivating the drug;
  • Changing the enzyme, protein, or receptor targeted by the medication;
  • Activating efflux pumps to remove the medicine from the cell;
  • Changing cell-wall proteins in order to inhibit medication uptake.

There are two basic genetic mechanisms initiating antibiotic resistance:

  • Mutation (a permanent change in genetic material);
  • Acquisition (occurs thanks to plasmids that share genetic material between cells).

What Bacteria Are Known to Be Antibiotic Resistant?

The following are antibiotic resistant bacteria examples:

  • Mycobacterium tuberculosis;
  • Pseudomonas aeruginosa;
  • Klebsiella pneumoniae;
  • Acinetobacter baumannii;
  • Staphylococcus aureus;
  • Burkholderia cepacia;
  • Neisseria gonorrhoeae;
  • Clostridium difficile;
  • Escherichia coli;
  • Streptococcus pyogenes.

Mycobacterium tuberculosis is resistant to isoniazid and rifampicin and may cause tuberculosis (also known as the White Plague and scrofula), which can be a deadly disease. Through the history of humanity, they have caused massive deaths. The signs of the disease were found in bodies of about 9,000 years old. It is believed that Nefertiti and her husband died from tuberculosis. The increase in antibiotic resistance began in the early 1990s.

Pseudomonas aeruginosa can cause pneumonia and a range of other infections. These bacteria mutate and adapt to various antibiotic treatments, causing complications in the treatment of cancer, AIDS, or cystic fibrosis. It is known to be insensitive to many antibiotics.

Klebsiella pneumoniae causes lung infections, pneumonia, and a range of other infections. It resists to different antibiotics. Usually, it attacks middle-aged and elderly men with weak immune systems. It is pretty often met in the US. It resists to the following medications: piperacillin, tazobactam, piperacillin, ceftazidime, cefepime, meropenem, imipenem, levofloxacin, ciprofloxacin, tobramycin, gentamicin, fosfomycin, colistin, and amikacin.

Acinetobacter baumannii causes such diseases as pneumonia, meningitis, and urinary tract infection. These bacteria can survive different conditions. These bacteria are able to resist tetracycline, aminoglycosides, aminocyclitols, chloramphenicol, carbapenems, beta-lactam antibiotics, and others.

Staphylococcus aureus (also known as MRSA) causes flesh eating disease, meningitis, skin disorders, pneumonia, and many others. This superbug is spread through human contact. It is resistant to various beta-lactam antibiotics, including dicloxacillin, methicillin, nafcillin, oxacillin, and the cephalosporins.

Burkholderia cepacia was discovered in 1949. It causes a range of disease, including pneumonia. It can be very dangerous. Although it may be treated with a combination of medications, it is resistant to different types of antibiotics, including penicillin.

Neisseria gonorrhoeae causes gonorrhea, which is spread through sexual contact. Certain strains of these bacteria are resistant to antibiotics. They are resistant to tetracyclines, penicillins, macrolides, spectinomycin, and quinolones.

Clostridium difficile causes diarrhea with further complications. Although it can be treated successfully, it quickly becomes resistance. That is why it is important to use antibiotics only if the treatment is clearly needed.

Escherichia coli cause urinary tract infection, meningitis, diarrhea, and other serious infections. Some strains of these bacteria are resistant to penicillin, fluoroquinolones, cephalosporins, and gentamicin.

Streptococcus pyogenes causes skin disorders and sore throat. These bacteria are found in 5%-15% of all humans, residing in the throat or lungs. It can be destroyed with penicillin, but several strains have built resistance to various antibiotics, including beta-lactams, aminoglycosides, macrolides, and others.