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MRSA Staphylococcus Aureus 4/12/2016 The Age of Modern Medicine The Battle of Resistance: Prior to Penicillin, the # 1 war-time killer was infection Treating Infections in the Age Began being mass produced in 1943 of Resistance ¾ Physicians were finally able to treat many diseases and childhood infections Mark T. Dunbar, O.D., F.A.A.O. ¾ This marked a new era in modern medicine Bascom Palmer Eye Institute Within 4 yrs of its release, resistance to University of Miami, Miller School of Med penicillin began popping up and grew at an Miami, FL alarming rate Mark Dunbar: Disclosure The Age of Modern Medicine Optometry Advisory Board for: By the mid-1940s and early 1950s streptomycin, chloramphenicol, and tetracycline had been ¾ Allergan discovered and the age of antibiotic therapy was ¾ Carl Zeiss Meditec underway ¾ ArticDx These new antibiotics were very effective against a number of different pathogens including Gram-(+) ¾ Sucampo and gram (-) bacteria, intracellular parasites, and tuberculosis. The mass production of antimicrobials provided a temporary advantage in the struggle with microorganisms ¾ Despite these rapid advances resistance quickly followed Mark Dunbar does not own stock in any of the above companies The Age of Modern Medicine Alexander Fleming is considered to be the father of modern medicine ¾ He discovered penicillin more How Resistance Develops than 70 years ago (1928) Considered to be one of the most significant medical breakthroughs of the twentieth century ¾ Ernest Duchesne was the 1st to describe the antibiotic properties of Penicillium sp. 1897 1 4/12/2016 Factors Implicated in Growing Bacterial Resistance Rates of Antibiotic Resistance Microbiological Bacterial become resistant when a ¾ Antibiotic misuse mutation occurs in the DNA that Environmental Factors protects the bacteria from a chemical ¾ Aging population ¾ Social behavior ¾ Mutation is only significant if the bacteria colony is exposed to the drug ¾ AIDS ¾ International travel “Survival of the fittest” dictates Technical Factors survival occurs in only those capable ¾ Increasing surgical of mutating intervention ¾ Organ replacement ¾ Life support systems Resistant Bacteria Susceptibility of Multidrug-Resistant Bacteria For any given bacterial population, 256 bacterial strains isolated from 164 patients random mutations will arise undergoing intraocular surgery b/w 1/2002 10/2002 With strong external selection pressures 124 (76%) coagulase-negative Staphylococci these mutations will be favored resulting High level of resistance to penicillin, aminoglycosides, macrolides, ciprofloxacin,ofloxacin in resistant bacteria Gatifloxacin and moxifloxacin had the lowest American Academy of Microbiology resistance frequency in the fluoroquinolones antibiotic group ¾ 17.8 million pounds of antibiotics are used Newer-generation fluoroquinolones provide excellent in animals each year broad-spectrum coverage against bacterial flora ¾ Human exposure of these antibiotics is isolated from conj, despite the high % of multidrug- resistant bacteria significant Miño de Kaspar et al. AJO 2005 Widespread Resistance Bacterial Resistance to Older Antibiotics 100% The problem is…. 90% 80% 70% Antibiotics are used extensively 60% 50% ¾ Topically 40% 30% 20% ¾ Systemically 10% 0% ¾ Agriculturally as a growth PercentageBacteria of Resistant Oxacillin Amikacin Penicillin Ofloxacin Cefazolin Neomycin Mezlocillin (Imipenem) Gentamicin Norfloxacin Cefotaxime Tobramycin Cefuroxime Meropenem Ceftazidime Tetracycline stimulant Gatifloxacin Moxifloxacin Levofloxacin Azithromycin Ciprofloxacin (Minocycline) Erythromycin Antibiotic (Vancomycin)l ¾ Most significant use of fluoroquinolones Chloramphenicol Miño de Kaspar et al. AJO 2005 2 4/12/2016 Staphylococcus Aures MRSA Pharmacology Methicillin was an antibiotic used Methicillin-Resistant many years ago to treat patients with Staphylococcus Aureus Staphylococcus aureus infections It is now no longer used except as a means of identifying this particular type of antibiotic resistance Staphylococcus Aureus MRSA Common bacteria usually found on the skin 1st outbreak identified in 1960 ‘s or in the nose Can cause a range of illnesses from minor Predominantly seen in hospitals, skin infections such as pimples, impetigo, chronic care facilities and parenteral boils, cellulitis and abscesses… drug abusers To life-threatening diseases such as pneumonia, meningitis, endocarditis, and The prevalence of MRSA isolates in septicemia hospitals in the US has risen steadily, There are many different types of staphylococcus aureus such that now about ¼ nosocomial isolates are methicillin resistant Staphylococcus Aures MRSA Pharmacology MRSA is a particular strain of Community-acquired MRSA is staphylococcus aureus that does not respond (is resistant) to many becoming a significant problem, with antibiotics the prevalence of MRSA among S aureus was sensitive to penicillin community isolates expected to reach when the drug was 1st introduced, but as high as 25% in the next decade resistance developed almost immediately as the organism acquired a β-lactamase enzyme that was capable of inactivating drug 3 4/12/2016 Reasons for Rise of MRSA Risk Factors for MRSA More powerful strains of MRSA Proloned hospital stays developing An increased number of very sick people in Prior surgery hospital Seriously ill in intensive care More complex medical treatments ¾ The use of central lines and catheters Immunocompromised Patients move within and between hospitals more often High workloads which result in less compliance with routine hand washing Multi-Drug Resistant 2005: Deaths from Bacteria MRSA Surpassed AIDS Emerging resistance of S aureus has also In 2005, AIDS killed 17,011 Americans been demonstrated for streptomycin, tetracycline, chloramphenicol, CDC reports > 90,000 get the potentially erythromycin and third-generation deadly "superbug" infections annually fluoroquinolones. T Recent JAMA surveillance study, only The topical 4th Generation about ¼ of MRSA infections involved fluoroquinolonesare are more potent hospitalized patients against MRSA than prior generation ¾ More than half were in the health care system fluoroquinolones People who had recently had surgery or were on kidney ¾ They inhibit both DNA gyrase and dialysis topoisomerase IV, requiring two genetic Open wounds and exposure to medical equipment are mutations for the bacteria to become resistant major ways the bug spreads. MRSA MRSA Facts About 1/3 of people carry MRSA on their MRSA has evolved into a multitude of skin or in their nose without knowing it genetically distinct strains that vary ‘ ’ These people are said to be carriers of widely in drug resistance, MRSA ¾ The bacteria are present on the body but transmissibility and virulence don’t cause any harm ¾ This is also referred to as being ‘colonised’ with MRSA Most people who carry MRSA in this way don’t go on to develop an infection 4 4/12/2016 4th Gen FQ Resistant Bacterial MRSA Facts Keratitis after Refractive Surgery Moshirfar M, J Cataract Refract Surg 2006; 32:515-518 Non-healthcare workers are now just as likely as healthcare workers to 2 Cases of Bacterial Keratitis resistant to carry MRSA on the conjunctiva and 4th Gen FQ lid margin 1st pt – Pseudomonas following PRK -> had been treated with Vigamox 2nd pt – MRSA following LASIK treated with Zymar…and Vigamox Culture susceptibilities resistance to both 4th Gen FQ 13 Cases of MRSA Following MRSA Fact Refractive Surgery While CA-MRSA strains tend to be Multicenter, retrospective chart less multi-drug resistant, some review of 13 cases of MRSA keratitis strains are associated with unusually following refractive surgery invasive infections of the eye and ¾ 9 were either healthcare workers or orbit exposed to a hospital surgical setting rd ¾ USA300 clone – CA-MRSA with the 7 pts were prescribed 3 generation PVL virulence marker FQ, 1 pt prescribed tobramycin, 1 pt was prescribed erythromycin and 3 were prescribed a 4th generation FQ Solomon. Am J Ophthalmol. 2007. Methicillin-Resistant Staphylococcus aureus Infectious Keratitis Following Refractive Surgery A retrospective chart review of cases occurring between May 2002 and February 2005 in 10 referral cornea and refractive disease practices Ocular Involvement of Prophylactic Antibiotics Unknown, 1 (bilateral)/13 patients MRSA Tobramycin 1/13 patients 7.7% 7.7% Erythromycin 1/13 patients 7.7% Third-generation Fluoroquinolones Ciprofloxacin or ofloxacin 53.4% 23.1% 7/13 patients Fourth-generation Fluoroquinolones Gatifloxacin or moxifloxacin 3/13 patients Solomon. Am J Ophthalmol. 2007. 5 4/12/2016 Infectious Keratitis in Refractive Eye Care Clinicians must be alert to the postop patient with signs and symptoms of Tracking Resistance possible post-LASIK and post-PRK infectious keratitis. PRK: Corneal scrapings, cultures, and sensitivities of all cases of focal infiltrates LASIK: Lifting the flap, scraping, culturing, and obtaining sensitivities on all cases of focal infiltrates Precautions for Culture Positive Rates Healthcare Workers BPEI 2011-2013 Patients exposed to healthcare facilities who are at higher risk of infection from nosocomial MRSA, prophylactically treat blepharitis with lid hygiene and hot compresses preoperatively Consider a nasal swab for MRSA carriage Consider bacitracin or a fourth-generation fluoroquinolone or bacitracin for preoperative prophylaxis Treatment of MRSA s/p Impact of Prior Therapy (59.8%)- LASIK Pathogen Recovery 2013*, N=338, Irrigating under the
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