Year 1 Medical Microbiology and Virology OSPE (Objective structured practical examination) SAMPLE OSPE QUESTIONS The following OSPE questions are examples. They are intended to allow candidates to become familiar with the style and content of the Year 1 OSPE. Answers, together with marks for each question, are also provided below. Please remember that the marking scheme is a general guide for the assessors/examiners. Please note that assessors/examiners, when marking OSPE papers will consider additional information provided by the candidates and may assess the overall standard of the responses. No Topic Additional materials provided at station 1 (Bank 6) 2 (Bank 12) Hepatitis B Hepatitis Report No MRSA infection and infection control Laboratory report No 3 (Bank 16a) 4 (Bank 17) Parvovirus B19 in pregnancy None No Coagulase negative staphylococcus in blood culture, i.e. likely contaminant x 4 Images No 5 (Bank 20) Containment Level 3 Laboratory (CL3) Picture of CL3 laboratory Cat 1 safety cabinet No 6 (Bank 30a) 7 (Bank 45) Catheter-associated UTI None No Writing a report: Understanding the concept of coloniser rather than pathogen CLED plate with a moderate pure growth of NLF. Image B Give oxidase result – positive Gram film of typical colony from CLED plate, Image A Image C: Mueller-Hinton agar (and appropriate sensitivities) with Pseudomonas aeruginosa – producing clear green pigmentation – with zone sizes and sensitivities, given (sensitive to ceftazidime, ciprofloxacin, gentamicin, pip-tazo and meropenem). 8 (Bank 50) Candidaemia ASM Assessor present? Slide/Image with Gram’s stain of positive blood culture containing a yeast (Candida spp.) April 2013 Page 1 of 17 V2 No No QUESTION 1 – HEPATITIS B Aims To assess: ability to interpret the results of investigations (Good Medical Practice curriculum - good clinical care). ability to liaise and discuss investigations with colleagues and to advise them appropriately (Good Medical Practice curriculum - good clinical care) understanding of wider public health issues understanding the role of immunisation in the protection of contacts Materials required Hepatitis report (included) Assessor required No Question A 24-year-old gay man visits his GP with a four-day history of increasing malaise, nausea and vomiting. That morning he noticed that his sclera were a deep yellow colour. His GP sent blood to virology and asked him to return the next day. Please examine the virology results and answer the following questions. 1. What is the most likely diagnosis in this patient? (5 marks) 2. Explain the hepatitis A results. (2 marks) 3. Explain the Hepatitis B results. (2 marks) 4. Explain the Hepatitis C results. (2 marks) 5. Give three possible risk factors for infection in this case. (3 marks) ASM April 2013 Page 2 of 17 V2 Marking scheme No. Question Answer Marks A 24-year-old gay man visits his GP with a four-day history of increasing malaise, nausea and vomiting. That morning he noticed that his sclera were a deep yellow colour. His GP sent blood to virology and asked him to return the next day. Please examine the virology results and answer the following questions. 1 What is the most likely diagnosis in this patient? Acute Hepatitis B. Hepatitis B infection. No marks for other answers. 5 2 (Max 5) 2 Explain the hepatitis A results. Past exposure to hepatitis A as total antibody is positive and IgM negative. 2 3 Explain the Hepatitis B results. All markers positive including HepB core IgM. All markers positive. 4 Explain the Hepatitis C results. No serological evidence of hepatitis C. 2 1 (Max 2) 2 5 Give three possible risk factors for infection in this case. Intravenous drug use. Sharps/needle stick injury. Male homosexuality. Transfusion of blood products. Tattoos and other piercing (contaminated instruments). 1 1 1 1 1 (Max 3) ASM April 2013 Page 3 of 17 V2 QUESTION 2 – MRSA INFECTION AND INFECTION CONTROL Aims To assess: To assess: core reporting skills, and be able to offer basic advice on the interpretation of laboratory results (fundamental skills) ability to analyse a clinical history in a relevant succinct and logical manner (good clinical care). ability to interpret the results of investigations (good clinical care). Ability to analyse and advise on clinical infection problems (good clinical care) a basic understanding of the management (under supervision) of common nosocomial infections (core knowledge) understanding of routes of transmission and methods of preventing nosocomial spread of common and important infecting organisms (core knowledge) Materials required Laboratory report (included) Assessor required No Question You receive a phone call from one of the FY2 doctors in the Minor Injuries Unit about a wound swab (taken a couple of days ago) that is awaiting authorisation. The patient has re-presented and is to be admitted with severe cellulitis spreading from the leg wound, temperature 38.5C with rigors. Look at the report that is provided and answer the following questions. Bigtown General Hospital Microbiology Laboratory Name: Susan Smith Age: 30 Ward: Minor injuries unit Specimen: Wound swab Clinical details: Fall at work, injury to leg. Culture Report: Staphylococcus aureus ++ Resistant to: penicillin, flucloxacillin, erythromycin Sensitive to: tetracycline, vancomycin, fusidic acid, rifampicin ASM April 2013 Page 4 of 17 V2 1. How is the organism that has been reported commonly known? (3 marks) 2. The FY2 wants to start the patient on cefuroxime. Is this a suitable choice? Justify your answer. (4 marks) 3. From the antimicrobials whose sensitivities have been reported, which agent/s would you recommend to treat this infection and by which route? (3 marks) 4. What other microbiology specimens would you advise taking? (3 marks) Marking scheme No. Question Answer Marks You receive a phone call from one of the FY2 doctors in the Minor Injuries Unit about a wound swab (taken a couple of days ago) that is awaiting authorisation. The patient has re-presented and is to be admitted with severe cellulitis spreading from the leg wound, temperature 38.5C with rigors. Look at the report that is provided and answer the following questions. 1 How is the organism that has been reported commonly known? MRSA. Methicillin-resistant S. aureus. Meticillin-resistant S. aureus. Any other name. 2 The FY2 wants to start the patient on cefuroxime. Is this a suitable choice? Justify your answer. No. Yes. MRSA are cefuroxime resistant. Other justification. 3 4 From the antimicrobials whose sensitivities have been reported, which agent/s would you recommend to treat this infection and by which route? Vancomycin, i.v. (plus or minus any sensitive oral agent). Vancomycin as oral therapy. What other microbiology specimens would you advise taking? Blood cultures MRSA screen (eg, nose & groin/perineum) ASM April 2013 Any two sensitive oral agents. Any single sensitive oral agent. Page 5 of 17 V2 3 3 3 0 (Max 3) 3 0 1 0 (Max 4) 3 0 1 0 (Max 3) 2 1 (Max 3) QUESTION 3 - PARVOVIRUS B19 IN PREGNANCY Mapping to Blueprint Good Medical Practice – good clinical care Stage A Curriculum – core knowledge – basic diagnosis and ability to distinguish between significant and non-significant pathogens Aims To assess: To assess knowledge of basic skills of viral diagnostics ability to liaise and discuss investigations with colleagues and to advise them appropriately (Good Medical Practice curriculum - good clinical care) Basic understanding and knowledge of the range of therapies available for infectious disease and the clinical indications for their use (Stage A - core knowledge) understanding of wider public health issues Materials required None Assessor required No Question An ultrasound scan of a fetus was carried out at 22 weeks gestation because the mother reported having a maculopapular rash at 14 weeks gestation. This scan revealed a hydropic fetus. 1. What is the most likely viral diagnosis? (4 marks) 2. What is the risk of congenital malformation from this infection? (2 marks) 3. What virological tests would you request on the mother? (4 marks) 4. What virological tests would you request on the fetus? (2 marks) 5. What treatment is available for the fetus? (2 marks) ASM April 2013 Page 6 of 17 V2 Marking scheme No. Question Answer Marks 1 What is the most likely viral diagnosis? Parvovirus B19 (erythrovirus) infection Human parvovirus 4 4 2 What is the risk of congenital malformation from this infection? No excess risk 2 3 What virological tests would you request on the mother? Paired serology (IgG) on booking blood and current sample. Serum B19 virus IgM B19 Virus PCR 2 4 What virological tests would you request on the fetus? B19 Virus PCR on amniotic fluid/fetal blood 2 5 What treatment is available for the fetus? Intrauterine blood transfusion 2 ASM April 2013 Page 7 of 17 V2 2 1 (Max 4) QUESTION 4 - COAGULASE NEGATIVE STAPHYLOCOCCUS IN BLOOD CULTURE, I.E. LIKELY CONTAMINANT Mapping to Blueprint Good Medical Practice – good clinical care Stage A Curriculum – core knowledge – basic diagnosis and ability to distinguish between significant and non-significant pathogens Aims To assess: ability to analyse a clinical history in a relevant succinct and logical manner (Good Medical Practice curriculum - clinical care) ability to identify common bacterial pathogens with confirmation of identity and distinction between significant and non-significant pathogens (Stage A – core knowledge) whether candidate has sufficient understanding of microbiology to offer basic advice on the interpretation of laboratory results (Stage A – core knowledge) Materials required x 4 Images (online on the College website) Assessor required No Question This question is based on a blood culture taken in your Accident and Emergency Department from a 68 year old female with clinical details given as: 'Fever ? UTI'. Please write a laboratory report with interpretive comments for this peripheral blood culture investigation positive in the aerobic bottle only after 3 days incubation. (16 marks) Image A Culture (A) derived from the single positive blood culture, on blood agar incubated aerobically for 24h Image B Gram film of typical colony from A Image C Staphaurex test on typical colony from A Image D Tube coagulase test on typical colony from A Image E Sensitivity plate from organism growing on A The sensitivity results are as follows: Cefoxitin = methicillin resistant clarithromycin resistant fusidic acid sensitive rifampicin sensitive gentamicin sensitive vancomycin sensitive ASM April 2013 Page 8 of 17 V2 Marking scheme No. Question Answer Marks This question is based on a blood culture taken in your Accident and Emergency Department - from a 68 year old female with clinical details given as: 'Fever ? UTI'. 1 Please write a laboratory report with interpretive comments for this peripheral blood culture investigation positive in the aerobic bottle only after 3 days incubation. ASM Coagulase negative staphylococcus isolated. From one of 2 bottles. After 3 days incubation. 3 2 1 (Max 6) Skin commensal of low pathogenic potential or likely skin contaminant or similar. Please repeat if clinically appropriate. No contaminant comment. No repeat requested. 5 April 2013 Page 9 of 17 V2 3 0 0 (Max 5) QUESTION 5 – CONTAINMENT LEVEL 3 LABORATORY (CL3) Mapping to Blueprint Curriculum Stage A – core knowledge, health and safety Aims To assess: Ability to understand principles of standard precautions, hazard groups and containment levels (Core knowledge) Knowledge of the essential features of a Containment Level 3 (CL3) laboratory (Core knowledge) Materials required Picture of a CL3 Laboratory - Images A&B (online on the College website) Assessor required No Question 1. What sort of laboratory is featured in Images A&B? (5 marks) 2. List FIVE essential features of this laboratory. (5 marks) 3. Which ACDP group(s) of organisms would be handled safely in this laboratory? [List groups not organisms] (5 marks) ASM April 2013 Page 10 of 17 V2 Marking scheme No. Question Answer Marks 1 What sort of laboratory is featured in Images A&B? CL3 5 2 List FIVE essential features of this laboratory. Negative pressure HEPA - filtered exhaust Sealable Separate work area Incorporate a lobby Glass window Dedicated equipment Warning sign Lockable door Authorised personnel only Internal alarm External switch for fumigation 3 Which ACDP group(s) of organisms would be handled safely in this laboratory? (List groups not organisms) Groups 1,2,& 3 Group 3 1 & or 2 Any mention of group 4 1 1 1 1 1 1 1 1 1 1 1 1 (Max 5) 5 4 1 0 (Max 5) ASM April 2013 Page 11 of 17 V2 QUESTION 6 - CATHETER-ASSOCIATED UTI Mapping to Blueprint Aims Be able to analyse a clinical history in a relevant succinct and logical manner (Good clinical care). Be able to interpret the results of investigations (Good clinical care). Be able to analyse and advise on clinical infection problems (Good clinical care) Be able to understand principles of standard precautions, hazard groups and containment levels (Core knowledge) To have a basic understanding of the management (under supervision) of common nosocomial infection (Core knowledge) To have a basic understanding and knowledge of the range of therapies available for infectious disease, the clinical indications for their use and their side effect (Core knowledge) Materials required None Assessor required No Question A 75-year old female was admitted following a fall at home. She had been very well until this event, and had had little contact with healthcare services. A urinary catheter was inserted for urinary retention. After several days, a urine culture showed the presence of Pseudomonas aeruginosa. The patient was systemically well until 3 weeks after admission when she became confused and developed a temperature of 38oC. She was started on oral nitrofurantoin. The following day, she remained febrile and had a rigor. 1. Would you routinely treat a patient with a positive catheter urine culture in the absence of systemic or urinary symptoms? Give TWO reasons to justify your answer. (3 marks) 2. Give TWO reasons why the episode of catheter-related infection is unlikely to respond to nitrofurantoin. (2 marks) 3. Name TWO antimicrobial agents that could be used to treat this patient, assuming P.aeruginosa is the cause of her infection. One of these should be suitable for use in a patient with a confirmed anaphylactic reaction to penicillin. (2 marks) 4. Does this patient require isolation on infection control grounds? Justify your answer. (2 marks) ASM April 2013 Page 12 of 17 V2 Marking scheme No. Question Answer Marks 1 Would you routinely treat a No patient with a positive Yes catheter urine culture in the absence of systemic or urinary symptoms? 1 0 Give TWO reasons to justify your answer. 1 Antibiotics do not eradicate the organism from the catheter May promote resistance Antibiotics do not reduce risk of febrile episodes Antibiotics predispose to C.difficile 1 1 1 Total 2 3 4 (Max 3) 1 1 Give TWO reasons why the episode of catheterrelated infection is unlikely to respond to nitrofurantoin. Name TWO antimicrobial agents that could be used to treat this patient, assuming P.aeruginosa is the cause of her infection. One of these should be suitable for use in a patient with a confirmed anaphylactic reaction to penicillin. Pseudomonas is resistant to nitrofurantoin. Nitrofurantoin only reaches therapeutic concentrations in the urine, serum levels inadequate to treat systemic infection Does this patient require isolation on infection control grounds? Justify your answer. No 1 Standard precautions when handling the catheter should be adequate to prevent spread of the organism. 1 ASM April 2013 Ceftazidime, piperacillin/tazobactam, meropenem (Max 2) 1 1 Gentamicin*, ciprofloxacin* (*In allergy) (Max 2) Page 13 of 17 V2 QUESTION 7 - WRITING A REPORT: UNDERSTANDING THE CONCEPT OF COLONISER RATHER THAN PATHOGEN Mapping to Blueprint Fundamental skills gained a basic understanding of quality assurance in the diagnostic laboratory developed, under supervision, core reporting skills sufficient understanding of microbiology, virology, mycology and parasitology to offer basic advice on the interpretation of laboratory results Core knowledge Basic biology Biological variability Host pathogen relationships Basic principles of diagnostic microbiology and virology Clinical syndromes - advice and management Good Medical Practice Clinical practice history, examination, management of chronic disease, continuity of care Investigation Decision-making Overall clinical judgement Epidemiology and screening Materials required CLED plate with a moderate pure growth of NLF. Image B Give oxidase result – positive Gram film of typical colony from CLED plate, Image A Image C: Mueller-Hinton agar (and appropriate sensitivities) with Pseudomonas aeruginosa – producing clear green pigmentation – with zone sizes and sensitivities, given (sensitive to ceftazidime, ciprofloxacin, gentamicin, pip-tazo and meropenem). The images are available on the College website Assessor required No Question History 52-year old female. 48 hours post cholecystectomy. She has a fever of 37.5 degrees centigrade and is clinically well. Wound has clear serous ooze without erythema. Patient had received ceftriaxone and metronidazole as prophylaxis. The wound swab is put up on blood agar (incubated aerobically and anaerobically) and on CLED*. Please examine Images A, B & C. Image B is derived from the wound swab after 18h of aerobic incubation and shows typical colonies on a CLED *(Cystine – Lactose - Electrolyte Deficient) agar plate. Moderate growth. ASM April 2013 Page 14 of 17 V2 Image A is a Gram film of a typical colony from the CLED plate. Typical colonies from the CLED plate are Oxidase Positive. Image C shows a Mueller-Hinton agar plate with sensitivity tests on typical colonies. Disk Cip 5 TZP 110 Antibiotic ciprofloxacin Piperacillintazobactam meropenem ceftazidime amikacin gentamicin Mem 10 Caz 30 AK 30 CN 10 1. Zone size 28mm 27mm Interpretation sensitive sensitive 25mm 25mm 22mm 21mm sensitive sensitive sensitive sensitive Write the laboratory report for this specimen that will be delivered to the ward. (10 marks) Marking scheme No. Question Answer Marks 1 Write the laboratory report for this specimen that will be delivered to the ward. Moderate numbers of Pseudomonas aeruginosa isolated Moderate numbers of Pseudomonas species Moderate numbers of oxidase positive GNB 2 Significance doubtful/likely coloniser only No interpretation of significance 4 0 Sensitivities available on request/not reported Sensitivities reported 4 0 ASM April 2013 Page 15 of 17 V2 2 1 (Max 2) QUESTION 8 - CANDIDAEMIA Aims Be able to demonstrate competence in taking relevant clinical/infection history To assess ability to identify common viral/microbial pathogens with confirmation of identity, and distinction between significant and non-significant pathogens To have a basic understanding of the management of deep infection (e.g. septicaemia, endocarditis, bone infection) To have a basic understanding of the management of common nosocomial infection (e.g. device-associated infection) Materials required Slide/Image with Gram’s stain of positive blood culture containing a yeast (Candida spp.) (online on the College website) Assessor required Yes The aerobic bottle of a blood culture from a 62-year old man became positive after 48 hours of incubation. He had been in the intensive care unit for the preceding 10-days with necrotising pancreatitis and had initially received piperacillin-tazobactam. He subsequently developed a fever, and was switched to intravenous meropenem although the fever had not resolved despite 5-days’ treatment with this. 1. What can be seen in the Gram’s stain of the blood culture? (2 marks) 2. When discussing this positive blood culture with the clinical team, what further information would you seek? (9 marks) 3. You discover that he has low blood pressure (82/50mmHg) but no other organ failure, has a central venous catheter in situ for CVP monitoring, and has received no antifungal drugs during this admission. (2 marks) What immediate patient management advice would you offer? (2 marks) 4. What advice about duration of treatment would you give? (4 marks) What further THREE investigations could help to guide duration? (3 marks) ASM April 2013 Page 16 of 17 V2 Marking scheme No. Question Answer Marks 1 What can be seen in the Gram’s stain of the blood culture material? Yeasts or Candida Fungi 2 1 (Max 2) 2 3 4 When discussing this positive blood culture with the clinical team, what further information would you seek? Severity of illness markers (haemodynamic status, inotrope requirements, ventilation requirements, white cell count, other organ failure, pancreatitis severity score etc). 3 Current/recent antifungal drug prescription 2 Presence of a central venous catheter Other interventions/surgical/radiological 2 2 (Max 9) You discover that he has low blood pressure (82/50mmHg) but no other organ failure, has a central venous catheter in situ for CVP monitoring, and has received no antifungal drugs during this admission. Any amphotericin B preparation Any echinocandin Voriconazole Fluconazole Itraconazole 2 2 2 2 1 What immediate patient management advice would you offer? Advise CVC removal/exchange 2 What advice about duration of treatment would you give? Typically 2 weeks (if uncomplicated) From fever resolution/last positive culture 2 2 (Max 4) What further THREE investigations could help to guide duration? Repeat blood culture Image abdomen (- ?collection for drainage) Fundoscopy Blood marker response 1 1 (Max 4) 1 1 (Max 3) (Total Max 7) ASM April 2013 Page 17 of 17 V2
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