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Article Critique=== ====== - gram positive bacteria

- Cell morphology is spherical and clustered

- Aerobic respiration

- pathogenic/ part of human micro flora

- symptoms of infection can vary from mild skin infection and food poisoning to pneumonia

- growing problem in today's world health care is Methicillin-resistant Sphylococcus aureus; over use of antibiotics

- Staph first identified by Sir Alexander Ogston (1880)

- Catalase positive meaning that when interacting with H2O2 (hydrogen peroxide) it will produce the catalase enzyme

- Coagulase positive

Article Draft
Peer review article: Staphylococcus aureus isolate from pediatric patients in Shanghai, China

The Discovery, and Molecular Pathogenesis of Methicillin Resistant-Staphylococcus aureus

Staphylococcus aureus is a gram positive, aerobic bacterium that is observed in the epidermal layer of the skin, nose and throat of many humans and animals. This bacterial pathogen is typically carried in the nose, throat and skin asymptomatically of individuals; however, open lesions on an immunocompromised 50% can lead to bacterial infection. When infected the bacterium can cause a range of minor to severe symptoms. S. aureus is considered part of the normal human microflora, and found in 50% of healthy adults In 1940 during World War II, Alexander Fleming was experimenting with the penicillin antibiotic that he derived from fungi, and its effects on S. aureus. During World War I, thousands of soldiers lost their lives due to bacterial infection. With Fleming producing large amounts of penicillin, and distributing them to infected patients the mortality rate significantly decreased. Later in the same year, an isolate of Escherichia coli was examined, and it was found to have contained a β-lactam ring enzyme capable of hydrolyzing penicillin (penicillinase).

Antibiotics resistance was first discovered in the early 1940s, and has only recently been a major issue for medical centers for about half a century. The initial rise of antibiotic resistance profiles occurred far earlier than the presence of man when bacteria attempted to out compete other species of bacteria inhabiting the same space for resources. These bacterium would produce their own antibiotic and antibiotic resistance profile in the effort of eliminating other bacteria without self-harm. As bacteria replicate, genetic information including resistant profiles are transferred through a process called horizontal gene transfer (HGT) as part of genome evolution.

In 1944 the first strain of S. aureus was found to have contained the penicillinase. Frighteningly, in only 4 years there was the first outbreak of penicillin-resistant S. aureus in a United Kingdom hospital. More than 50% of the isolates taken from infected patients contain the penicillinase enzyme. To combat the penicillin resistant S. aureus, methicillin was created as a derivative of penicillin that was able to resist the penicillinase enzyme. Within the same year at Queen Mary’s Children’s Hospital in Carshalton, an outbreak had occurred with S. aureus strains resistant to methicillin. The United States recorded its first case of methicillin-resistant S. aureus in 1968. Present day roughly two out of every one hundred individuals in the United States carry MRSA.

MRSA is commonly known to be hospital affiliated (HA-MRSA); however, there has been an increase of prevalence among individuals who have never been hospitalized, characterized as community associated (CA-MRSA). A study in Shanghai dicovered that the most common strain of MRSA contains the molecular profile ST59-MRSA-IV and ST59-MRSA-V. These two strains showed complete resistance to the antibiotics clindamycin, erythromycin, and tetracycline while other strains expressed different profiles.

To conduct the experiment, researchers collected 80 isolates from children admitted for the first time at Shanghai Children’s medical center. Within 48 hours of hospitalization, samples were taken to avoid any contamination from hospital equipment reducing the probability of tainting the experiment examining CA-MRSA not HA-MRSA. Normal biochemical testing was performed to determine the presence of S. aureus. The experiment further used MLST analysis, SCCmec and Spa typing to examine molecular patterns between isolates. There has been research to show that the different molecular typing has its own unique antibiotic resistance profiles which serves as an important reference for healthcare professionals to consider when treating infected patients. Researchers, and other medical professionals have concluded that a simple yet effective technique to combat different strains of MRSA could be as simple as rotational antibiotic use.

Lead Section
Methicillin-Resistant Staphylococcus aureus is a unique strain of S. aureus that expresses an antibiotic resistance profile. Commonly known as MRSA, this "superbug" has the ability to withstand many of the antibiotics that are typically use to treat minor to severe staphylococal infections. Because Methicillin-Resistant Staphylococcus aureus is still S. aureus, the strain shares the same morphology and characteristics such as having a thick peptidoglycan cell wall (gram positive), operates using a facultative anaerobe respiration, in addition to sharing many of the same enzymes. The resistance profile for MRSA developed in multiple stages. Before methicillin was created in 1958, penicillin was the primary antibiotic that was used to treat bacterial infections; however, after wide spread use bacterial resistance was seen. An enzyme that was first seen in Escherichia coli called penicillinase was able to be transferred to the staphylococal genus via conjugation. MRSA for the best have century has been increasing in prevalence and continues to be a major issue in healthcare today.

https://en.wikipedia.org/wiki/Staphylococcus_aureus