Case Study Pathogenic Bacteriology 2009

1. Case StudyPathogenic Bacteriology2009 Case # 33 Julie Yang Note: Embedded in your PowerPoint, you must address all questions in the case!

2. Case Summary The patient is a 44-year old male, with a medical history significant for hypertension, non-insulin dependent diabetes, hypercholesterolemia, and a history of heavy smoking (2 packs a day). He came to the hospital suffering a myocardial infarction. It was discovered that upon a caridac catheterization the patient had a 3-vessel coronary artery disease. The hospital decided to do a triple coronary artery bypass graft-surgery. 2 days after the surgery the patient had developed septic shock with acute renal and respitory failure. The patient was intubated. His symptoms are a fever of 39.3°C, low blood gas, and an above average white blood cell count. Upon investigation there was a development of a pleural effusion in the lower left lobe of the lung. A chest tube was put in to drain the effusion. After 3 days, pus also began to develop around the sternal wound.

3. Key Information Pointing to Diagnosis • The patient is immuno-compromised by his heart attack • The patient also had open heart surgery • The patient has sepsis and renal failure which indicates that hemolysins are present in his blood • The patient had septic shock within 48 hours of his surgery • 5 other heart surgery patients in the hospital also have these same symptoms, this indicates a community pathogen • Patient has pleural effusion • Patient has pus forming around his chest tube

4. The Diagnosis According to the CBA plate, gram staining, and the antibiotic testing, It is estimated that this pathogen is Staphylococcus Aureus and it is possibly MRSA

5. Classification,Gram Stain Results, and Microscopic Appearance of Pathogen X • CBA plates show β hemolysis • Gram stain is positive (+) cocci in clusters • A kirk-bauer antibiotic screening indicates that the organism is vancomyacin and TMP/SMX sensitive and oxacillan and penacillan resistant.

6. Diseases and Pathogenesis of Disease Caused by Pathogen • MRSA is a disease on the rise. This form of noscomial pathogen has become a prevalent form of disease in hospitals transmitted by unclean hospital practices and poor screening methods. • S. aureus can cause diseases such as pneumonia, sepsis, urinary tract infections, and surgical wound infections • This pathogen is hearty and can survive for long periods of time on clothing and plastic objects • MRSA has an ability to produce beta-lactamase which causes penacillan resistance • Because it confers beta-lactam resistant anitbiotics such as oxacillan it is a difficult organism to kill

7. Diagnosis/Isolation/Identification/ of Pathogen • Diagnosis: The patient’s pathogen is S. aureus. It might be due to a community pathogen because 5 other patients who underwent heart surgery also have the same symptoms and test results. Most often S. aureus originates as a nosocomial pathogen and is spread to other patients by hospital staff or from patient to patient • Isolation: This organism can be isolated from the blood and grown on a CBA plate. • Identification: Coagulase test, Slidex-staph kit (agglutination kit), PCR, hemolysis capability (CBA)

8. Therapy, Prevention and Prognosis of Patient Infected with Pathogen • Since the organism is vancomyacin sensitive the patient will receive vancomyacin in his IV. Though the organism is sensitive to vancomyacin it has been shown that MRSA can confer intermediate resistance to vancomyacin after prolonged use. • Prevention of this disease can be to use cleaner hospital practices outlined by the CDC, or screening patients and staff in ICU’s and surgical wards • The prognosis of this patient is undecided, because the patient’s antibiotic screening shows that it is a strain of s.aureus that is still sensitive to vancomyacin, but it may confer intermediate resistance later on.

9. Primary Research Article Contributing to the Understanding of the Disease caused by Pathogen • Chaberny I.F, et al, 2008, Impact of routine surgical ward and intensive care unit admission surveillance sultures on hospital-wide nosocomial methicillin-resistant Staphylococcus aureus infections in a university hospital: an interupted time-series analysis, J. Antimicrobial Chemotherapy, 62: 1422-1429. • The test was performed over a 5 year period in Hannover Medical School Hospital. The research was conducted in the ICU and the surgical ward which consisted of 1400 beds. The method used was surveillance of the patients before screening was conducted and after screening was conducted. The microbiology tests performed were hemolysis on CBA plates, mannitol salt agar, gram stain, catalase test, coagulase test, and antibiotic susepibility tests. • How does this article relate to and support your case? • My patient and the 5 other patients infected all are immunocompromised surgical patients that are not known to have been screened before entering the hospital for MRSA.

10. Primary Research Article Contributing to the Understanding of the Disease caused by Pathogen • How does this article relate to and support your case? • My patient and the 5 other patients infected all are immunocompromised surgical patients that are not known to have been screened before entering the hospital for MRSA.

11. Take Home Message • MRSA involves immunocompromised patients and improper cleaning and screening practices in hospitals. • Typical symptoms are symptom sepsis, pneumonia and infections of wounds. • Pathogen is a form of s. aureus • Diagnostics include test oxaxcillan susceptibility tests, coagulase test and sequencing of strain. • Therapy is based on antibiotic screening • Prognosis is undecided for this patient because the strain is sensitive to vancomyacin (last-chance antibiotic) • Prevention is screening patients and cleaner practices by hospital staff • Transmission is via contact with infected person (by touch or contact) or through dirty instruments. • Threat is that the strain of MRSA will be one that is not susceptible to any antibiotic treatment

12. References • Chaberny I.F, Schwab F, Ziesing S, Suerbaum S, Gastmeier P, 2008.Impact of routine surgical ward and intensive care unit admission surveillance sultures on hospital-wide nosocomial methicillin-resistant Staphylococcus aureus infections in a university hospital: an interupted time-series analysis, J. Antimicrobial Chemotherapy,62: 1422-1429 • Wichelhaus T.A, Kern S, Schafer V, Brade V, 1999. Rapid detection of epidemic strains of methicillin-resistant Staphylococcus aureus, J. Clinc Micro,37: 690-693 • Pentaki E, Miriagou V, Tzouvelekis L.S, Pournaras S, Hatzi F, Kontos F, Maniati M, Maniatis A.N, 2001. MEthicillin-resistant Staphylococcus aureus, in the hospitals of Central Greece J. Antimicrobial Agents,18: 61-65