Model Answers Microbiology Written examinations 2007 - RCPA

More documents

Recommendations

Info

Question 4. Write short notes on: Norovirus detection Role of anaerobic blood cultures Flocked swabs Non cultivable bacteria Norovirus detection +ss RNA virus; Calciviridae, human calici virus distantly related to the other human calicivirus....sapovirus. 2 strains of Norovirus, genotype 1 and 2. Responsible for acute gastroenteritis. Nausea 9%, vomiting 69% and diarrhoea 66%, abdominal cramps 33% also headache, fever, chills reported. first recorded epidemic in 1968. Norwark virus. Epidemics occur in winter and spring and low background disease throughout the year. Often associated with hospitals, nursing homes, cruise ships, restaurant s and schools. Virus shed in vomitus and faeces. Faecal oral and vomitus oral eg alleged vomitus aerosol landing on food or fomites and then being consumed. In developed countries 50% population infected by 5 th decade. Acquired earlier in developing companies with poor sanitation. Gut virus receptor related to certain blood group antigens. Blood group B individuals are resistant to infection. RNA codes 3 ORF: ORF 1 encodes a non structural polyprotein that self cleaves to form 6 structural proteins. ORF2 the capsid protein; ORF3 a minor structural protein. Diagnosis : RT-PCR of faeces or vomit. EM and IEM used in the past. Antigen based tests available but have low sensitivity and do not cover all human strains of norovirus probably due to antigenic variability/instability. (genotype 2 common strain in Australia Role of anaerobic blood cultures Past blood culture studies have shown rates of anaerobic bacteraemia of 10-15%. More recently this rate has fallen. ~5%. Finding anaerobes must be taken seriously as they can indicate important underlying primary infection or underlying disease. B frag = intraabdominal infection, F necrophorum + Lemmiere‟s disease or necrobacillosis with venoocclusive complications, clostridial sp and association with colonic cancer, gas gangrene. Often polymicrobial bacteria in gut disease. Automated systems detect anaerobes at similar rates Flocked swabs Used for 2 reasons; > nasopharyngeal cells cp cotton tipped swabs or NPAs, better detection of N gono and Chlamydia. Nylon, > absorbtive surface, non inhibitory Non cultivable bacteria Recent molecular tools suggest that non cultivable bacteria exist in many situations such as the gut. These organisms do not yet grow on defined media. An example is
Tropheryma whippelii the cause of whipples disease. This organisms was visualised in tissues but has not yet been cultured., identified using 16sRNA PCR. Interest in these organisms in chrons disease, inflammatory joint disease. T pallidum, C trachomatis are also non cultivable. Other reasons for inability to culture include prior use of antibiotics, dormant bacteria Question 5: Write short notes on Kohler illumination Gram‟s stain Use of a biological safety cabinet Disinfectants for use in the microbiology laboratory See attached paper for answers to all of these questions
Page 1 and 2: Model Answers Microbiology Written
Page 3 and 4: Sensitivity testing of yeasts Brief
Page 5 and 6: Swabs versus fluid samples for exam
Page 7: S. aureus and MRSA S. aureus: tradi
Page 11 and 12: General principles Routine vs selec
Page 13 and 14: 2. Sensitive and specific reliable
Page 15 and 16: CMV VZV HSV 1. Detect foetal damage
Page 17 and 18: Question 1, Marker 2 What is the ro
Page 19 and 20: Question 3, Marker 1 What do you co
Page 21 and 22: Question 3, Marker 2 What do you co
Page 23 and 24: Question 4, Marker 1 Laboratory not
Page 25 and 26: Question 6, Marker 1 List the sampl
Page 27 and 28: Bird seed - to confirm Crypto Ecto
Page 29 and 30: o Disc diffusion • M$$-P standard
Page 31 and 32: o o o Agar dilution - Middlebrook 7
Page 33 and 34: Collection of tissue for those with
Page 35 and 36: Normal cell count
Page 37 and 38: Question 11, Marker 2 Describe, wit
Page 39 and 40: Mock exam Queensland trainees 2007
Page 41 and 42: Serological methods for detection o

Model Answers Microbiology Written examinations 2007 - RCPA

Create successful ePaper yourself

Delete template?

Save as template?