Answer to Question #118095 in Human Anatomy and Physiology for MAKHUOGA ALFRED FRIDAY

Question

Antibiotics are used to treat a wide variety of bacterial infections and have saved millions of lives since they were first introduced in the 1940s and 1950s. However, due to both overuse and misuse, many are no longer effective and The World Health Organisation (WHO) considers the emergence of new antibiotic-resistant bacteria to be a serious threat to global public health. According to their mechanism of action, antibiotics can be divided into three main groups, those inhibiting cell wall synthesis, those inhibiting protein synthesis and those that inhibit nucleic acid synthesis. Choose a disease or an organism that has a well-documented mechanism of resistance (such as methicillin resistant Staphylococcus aureus - MRSA or tuberculosis) and see if you can identify the gene or genes that confer resistance and the method of DNA transfer thought to contribute to its spread. This may be from one organism to another or may simply be passed down from mother to daughter cell due to environmental pressure.

Answer 1

S. Aureus was identified by Sir Alexander Ogston in 1880. Since then, it has been transmitted to approximately 30% of the population and can be found as a normal inhabitant of the skin flora, namely. in the nostrils and reproductive tract of women. S. Aureus is not mobile and anaerobic, and under a microscope it is considered as a “grape cluster berry”. Reproduced asexually through binary division. Its immovable characteristic makes it spread through human-to-human contact or through contact of contaminated surfaces and food products. Similarly, MRSA is distributed mainly through human-to-human contact through hands and often through the cough of a patient infected with MRSA III pneumonia.

MRSA is the evolution of S. Aureus in at least 5 different multistable strains. This resistance increases the difficulty of treating the infection. Resistance is mainly due to the fact that MRSA thrives in the antibiotic-like penicillin company due to the resistance gene in the developed S. Aureus, which prevents antibiotic deactivation by enzymes responsible for cell wall synthesis. The synthesis of cell wall material is critical for bacterial growth. MRSA was first identified by British scientists in 1960. The next step was a vancomycin resistant S. Aureus strain, discovered in Japan in 2002.

S. Aureus resistance infections include

  1. Methicillin-resistant Staphylococcus Aureus (MRSA)

  2. Vancomycin-resistant Staphylococcus Aureus (VRSA)

  3. Vancomycin-intermediate Staphylococcus Aureus (VISA)

Related diseases

S. Aureus causes the following infections:

  • Dermatitis

  • folliculitis

  • cellulite

  • Abscesses

  • Pneumonia

  • Staphylococcal endocarditis

  • Food poisoning (gastroenteritis)

  • Septic arthritis

  • Osteomyelitis

  • bacteremia

S. Aureus is the main cause of infectious endocarditis, bacteremia, skin infections and device-related infections.

MRSA causes the following diseases:

  • Sepsis

  • Necrotizing pneumonia

  • Necrotic fasciitis

  • Impetigo

  • Abscesses

  • cellulite

  • folliculitis

  • Infectious endocarditis

    

Epidemiology

In developed countries, the incidence of S. Aureus ranges from 10 to 30 per 100,000 of the population, and hospital acquired infections are a key factor. It has been suggested that bacteria are transferred through medical workers from pets to work environments. Because of S. Aureus, they are found as residents of pets. In addition, it can be transmitted from infected patients to non-infected patients through medical professionals. Studies show that S. Aureus can survive for three months on polyester fabric, that is, in closed curtains for hospitals. Simarlarly, MRSA can survive on surfaces and fabrics.

The incidence of MRSA infection has fluctuated, increasing from 0 to 7.4 per 100,000 in Quebec, Canada. Since 2005, the incidence of MRSA has been reduced, possibly due to improved infection control procedures. The incidence of S. Aureus is highest in infants and increases with age (over 70 years). Persons with HIV / AIDS have a significantly higher incidence rate, namely: 494 per 100,000 of the population and 1960 per 100,000 of the population, according to two separate studies.

Regarding MRSA incidence rates, the Centers for Disease Control and Prevention claims that two out of 100 of the population are carriers for MRSA. Unfortunately, there is no evidence of MRSA skin infections. However, studies show that the incidence of MRSA infections in health facilities has decreased by 50% .IV

Diagnostics

S. Aureus is diagnosed by laboratory testing of appropriate specimen samples. Bacteria are identified using a biochemical or enzyme test. Whereas MRSA is diagnosed using quantitative PCR procedures, broth microdulation tests, a cefotitin lid screening test and latex agglutination test to quickly identify strains.

Treatment

The first line of treatment for S. Aureus infections is penicillin or penicillin-stable penicillin, which inhibits the formation of peptidoglycan crosses, which give strength to the bacterial cell wall. Consequently, cell wall formation worsens, leading to cell death. However, some S. Aureus strains are re-resistant to penicillin, for example, in MRSA. These strains are then treated with vancomycin, which also inhibits peptidoglycan by binding to amino acids in the cell wall.

Infection control

S. Aureus is distributed through humans and humans, as well as through pets. Therefore, great attention should be paid to hand washing in order to limit the transmission of bacteria. Medical facilities and workers should use disposable gloves and aprons, thereby reducing bodily contact and transmission of MRSA can be reduced.