Staphylococcus aureus organisms stubborn and antibiotic-resistant - The Kingston Whig-Standard

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This article is not medical advice. If you have concerns, please consult your physician or medical professional.

It's unnerving, thinking about invisible microorganisms creeping around on us, inside and out. Microscopic bugs find humans to be comfortable homes, and in some cases, it is beneficial to both. Then there are the hostile germs. Staphylococcus aureus (SA) is a global bacterial concern, "one of the most common causes of skin, soft tissue and nosocomial (originating in hospital) infections," Health Canada stated.

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Presenting in several strains, the staph infection may cause mild illness to life-threatening disease. Methicillin-resistant-Staphylococcus-aureus (MRSA) is no longer rare, nor is CA-MRSA (community-acquired MRSA).

Thriving in human bodies, Staphylococcus aureus is also present in domestic animals, farm livestock and wild animals. Humans can be long-term carriers or occasional carriers, with SA found "in the nose, groin, axillae, perineal area (males)." It is also located "in the mouth, mammary glands, hair and the intestinal, genitourinary and upper respiratory tracts," Health Canada described.

"At any time, between 20 and 30 per cent of the general population carry Staph bacteria on their hands or in their noses but are not ill," Public Health Agency of Canada said. The carriers may be well but still able to pass on CA-MRSA or strains that are not resistant. Catching bacteria from tainted food, from an "infected person or from a contaminated surface, you can spread it to others if you don't clean your hands properly." Moreover, "you can also infect yourself through an open wound on your own body."

Health-care facilities and hospitals suffer outbreaks of MRSA due in part to caring for patients with compromised immune systems. The resistant pathogen appeared in the United Kingdom in 1961, when methicillin replaced penicillin to combat SA infections. In Canada, MRSA developed in a hospital in the early 1980s; community-acquired infections emerged in the early 2000s. The two resistant bacteria are not the same.

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Infecting healthy humans, community-acquired MRSA may cause acute illness. "CA-MRSA strains display enhanced virulence, spreading more rapidly and causing more severe illness than HA-MRSA (hospital-acquired) strains," Elena Mitevska et al wrote in the journal Pathogens, April 10, 2021. "Importantly," Mitevska said, "unlike in other parts of the world, the majority of MRSA infections in Canada remain attributable to health-care exposure."

Staphylococcus aureus generally forms in clusters. The bacteria spread at every opportunity. In laboratory analysis, SA can be found in samples of blood, urine, feces, abscesses and in aerosols, cerebrospinal fluid and joint aspirates, PHAC noted. To find the pathogen, specimens are cultured and killed, then stained with chemicals. Prepared on slides for microscopic examination, the suspected bacteria may be determined to be gram-positive, catalase-enzyme-positive, and part of the Staphylococcaceae family.

Danish bacteriologist Christian Gram devised lab staining procedures in the late 1800s. The uncomplicated Gram's Stain "enabled bacteria to be divided into those that it turns blue — gram-positive — and those that it turns red — gram-negative," Dr. Henry Marcovitch said in Black's Student Medical Dictionary (Bloomsbury Publishing Inc., 2015). Directing the physician toward which antibiotic to use, "gram-positive bacteria are usually more susceptible to penicillin than gram-negative organisms."

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Discovered by chance in 1928 in the hospital laboratory of British physician and scientist Alexander Fleming, the antibiotic penicillin was isolated and refined, then made available in 1946. (Other medical professionals were looking for innovative drugs as well.) As the need for penicillin flourished, "the overuse and misuse of antibiotics in medicine, veterinary medicine and the animal food industry (contributed) to the evolution of bacteria that are resistant to antibiotics," Marcovitch wrote.

The tenacious resistance resulted in MRSA, VRSA (vancomycin-resistant Staphylococcus aureus), C. difficile (Clostridium difficile), and others. (C. difficile bacteria cause mild to severe diarrhea and inflammation of the colon.) Antimicrobial resistance is a global threat to human health and life.

Worldwide, deaths from antimicrobial-resistant bacteria were estimated at 1.27 million people in 2019, according to The Lancet report on Jan. 19, 2022. Infections of the lower respiratory system were the leading cause.

In Canada, Public Health Agency of Canada statistics from 2008 to 2012 noted that "approximately nine per cent of patients with a clinical (non-blood) MRSA infection died and 25 per cent of patients with a MRSA bloodstream infection died 30 days after the date of positive culture."

Pathogens spread when food contaminated with the staph bacteria is consumed. The insertion of catheters and intravenous devices may give SA a chance to develop, as well as changing dressings on open wounds, or touching lesions. Handwashing is critical, both before and after the care. Personal protective equipment — disposable gowns and disposable gloves — will help. If splashing is possible, eye protection such as goggles, glasses or face shields is useful.

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MRSA organisms are stubborn. They "can survive on some surfaces, like towels, razors, furniture and athletic equipment for hours, days or even weeks," the Center for Disease Control and Prevention said. Wash hands with soap and water for at least 20 seconds, or use alcohol-based hand sanitizer. Laundry should be washed on the warm settings, but hot is not needed to kill the germs, according to the centre. Clean and disinfect surfaces, and keep any wounds covered.

The procedure for changing MRSA dressings at home takes extra steps, according to WoundsCanada.ca. (Please see the site for complete information.)

  • Gather supplies and wash hands with soap and water
  • Put on a clean pair of disposable gloves
  • Remove the dressing or bandage and place in a plastic bag
  • Remove the gloves and place in the same plastic bag
  • Wash hands with soap and water again
  • Put on another clean pair of disposable gloves
  • Tend to the wound and apply a fresh bandage
  • When completed, remove the gloves and place in the same plastic bag
  • Tie the bag shut and toss into the garbage
  • Wash hands thoroughly once more in soap and water

Researchers internationally are working towards new antibiotics and new ways of destroying dangerous bacteria. We can have a role, too, through good hygiene, avoiding contaminated food, and washing our hands.

Susanna McLeod is a writer living in Kingston.

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