Winter 2012 Doctors’ Newsletter Page 2 The pathologists of DHM & BSP Dr Colin Goldschmidt Pages 3-4 New Pathologists Pages 5-6 Clostridium difficile Infection Dr Ian Chambers Page 7 Parapertussis Dr Michael Wehrhahn Pages 8-9 Chlamydia trachomatis infection Dr Ian Chambers Pages 10-11 Rapid Identification of Bacterial Pathogens by MALDI-TOF Mass Spectroscopy Dr Michael Wehrhahn Dr Ian Chambers The pathologists of DHM & BSP The pathologists of Douglass Hanly Moir Pathology (DHM) and Barratt & Smith Pathology (BSP) operate at the heart of our operations, the laboratory. As directors and supervisors of the lab, they assure the integrity of our results by assessing and monitoring our methods, systems, quality control, staff and equipment. They analyse results and provide interpretative comments. And they teach. Dr Colin Goldschmidt Chief Executive Officer As the essential link between clinician and laboratory, our pathologists spend much of their time in telephone consultation with clinicians, providing assistance with the interpretation of results and offering assistance in the area of clinico-pathological correlation. They are directly involved in all labrelated management decisions and, under our commitment to ‘medical leadership’, they play a pivotal role in shaping all decisions in the company. We remain ever-committed to operating DHM and BSP as a Medical Practice, rather than purely as a business. In this way, quality, service, ethical practice and good medicine will prevail. DHM and BSP employ far more pathologists than any other pathology company in NSW. Over the past two decades, we have developed specialised expertise in almost all areas of laboratory testing, largely as a result of the expertise and specialised makeup of our pathologist team, which has expanded in tandem with the growth of the practice. In this edition of the Doctors’ Newsletter, we introduce to you a group of new DHM pathologists who have recently joined the practice and whom we welcome most warmly. If you thought that all pathologists were the same, then think again! At DHM and BSP we have haematologists, chemical pathologists, microbiologists, immunologists, genetic pathologists, histopathologists, cytopathologists, gynaecological pathologists, dermatopathologists, uropathologists, neuropathologists and others. We even have one pseudopathologist – that’s me, in my administrative, non-practising role in the practice! 2 We encourage you to call our pathologists at any time. When you call, you will be directed to the pathologist of your choice or to a specialist pathologist who is most appropriate for your particular enquiry. And finally, if you wish to discuss any matter that matches my ‘speciality’, I shall be delighted to take your call myself! Thank you for your support of our pathology practice. With my warmest regards, Dr Colin Goldschmidt MB BCh, FRCPA CEO Douglass Hanly Moir Pathology Barratt & Smith Pathology New Pathologists DR ALEXANDRA ALLENDE MB, BS, PhD, FRCPA Specialty: Histopathology Special interests: Ocular, gastrointestinal, urological, breast and skin pathology Dr Alex Allende is a medical graduate of the University of Sydney. Following extensive experience in clinical medicine for several years, with particular interests in ophthalmology and research, she undertook a Doctorate of Philosophy in the discipline of ophthalmology at the University of Sydney, with the support of an NHMRC scholarship. The thesis, incorporating histological and molecular studies into the mechanisms of vascular development in the choroid and retina, inspired her to train in anatomical pathology, which was undertaken primarily at Westmead Hospital, with additional rotations to Nepean Hospital and Douglass Hanly Moir Pathology. Following completion of training, which included teaching, journal publications and conference presentations, she joined the histopathology department at Douglass Hanly Moir and is developing her knowledge further by following interests in ocular, gastrointestinal, urological, breast and skin pathology. DR JULIET BURN MB, BS, FRCPA, MIAC Specialty: Histopathology Special interests: Pulmonary, breast and gastrointestinal pathology, dermatopathology and cytopathology Dr Juliet Burn graduated from the University of New South Wales in 1980 and obtained her Fellowship of RCPA in 1987. She joined the small independent practice, Davies Campbell de Lambert Pathology, in 1988 and became a principal in 1991. Dr Burn held Visiting Medical Officer positions at Auburn Hospital and ICPMR Westmead, from 1988 until 2006. She has held positions on the Board of Censors RCPA and, since 1993, she has been regularly involved in quality assurance in pathology in Australia and overseas. Dr Burn has extensive experience in teaching and supervision of RCPA pathology registrars and in participation in multidisciplinary meetings (dermatopathology, gastrointestinal and breast pathology). She also has extensive experience in diagnostic histopathology and cytology, with a special interest in skin, breast, lung and gastrointestinal pathology. DR ROBERT CORTIS-JONES MB, BS, FRCPA Specialty: Histopathology Special Interests: Dermatopathology, melanoma and inflammatory skin disorders As an undergraduate at the University of Sydney from 1960 to 1965, when pathology was a major component of the medical course, Dr Robert Cortis-Jones decided he wanted to become a pathologist. Most of his post-graduate training in pathology was at Sydney Hospital, which was, at that time, the location of the Melanoma Unit, making melanoma a significant professional interest for him. He completed his pathology training in 1973 and then spent two-and-a-half years in tropical Townsville, at the Australian Government Pathology laboratory. This further increased his interest in skin tumours, particularly melanoma. Dr Cortis-Jones moved to Wollongong as the Director of Anatomical Pathology for the Illawarra Area Health Service from 1984 to 2000, covering almost all areas of Anatomical Pathology. Returning to Sydney, and now happy to specialise in just one area, from 2002 to 2010 he was a pathologist at Combined Pathology, Gordon. This laboratory served skin cancer clinics across Australia, from Brisbane to Perth. Dr Cortis-Jones joined Douglass Hanly Moir Pathology in October 2010, after Combined Pathology was bought by Sonic Healthcare. During his career, he has seen major changes in the early diagnosis of melanoma, the result of collaboration between pathologists, both in Australia and abroad, and the great benefits of early diagnosis and treatment Dr Cortis-Jones is now looking to increase his expertise in inflammatory skin disorders. DR SIMON CLARK MB, ChB, FRCPA Speciality: Histopathology Special Interests: Dermatopathology and education Dr Simon Clark graduated from the University of Otago, New Zealand. His training in pathology and histopathology began in Wellington Hospital and was completed at Royal Melbourne Hospital. Dr Clark completed a Fellowship of Dermatopathology at the Skin and Cancer Foundation, Sydney. He has worked in public and private pathology and has lectured at the University of Melbourne and the University of Queensland. Dr Clark continues to be extensively involved in general practitioner education in skin cancer medicine. He presently runs the pathology component of the post-graduate certificate courses in skin cancer medicine at the University of Queensland and also lectures in the Masters of Medicine course. Dr Clark joined Douglass Hanly Moir Pathology in October, 2011. 3 New Pathologists DR LISA LIN MB, BS, BSc (Med), FRCPA Specialty: Histopathology Special interests: Breast and genitourinary Dr Lisa Lin graduated from University of New South Wales in 2004 and completed her internship and residency training at Royal Prince Alfred Hospital, Sydney. She commenced her anatomical pathology training at John Hunter Hospital, Newcastle, in 2007, after which her training was predominantly based at Westmead Hospital, Sydney. Dr Lin also gained experience working at different public and private laboratories through rotations to Douglass Hanly Moir Pathology, Royal North Shore and Nepean Hospitals and the Department of Forensic Medicine, Glebe. During her training, Dr Lin has been involved in a number of publications in peer-review journal articles, and also co-authored a textbook chapter. She has special interests in breast, genitourinary and gynaecological pathology. DR SCOTT MEAD MSc (Hons), PhD, MBChB, BHB, FRCPA Special interest: Genetic pathology Dr Scott Mead graduated from the University of Auckland (New Zealand) where he also gained a PhD in Molecular Medicine. His pathology training was undertaken at Christchurch School of Medicine (University of Otago) and Royal Prince Alfred Hospital, Sydney. Dr Mead has a long-standing interest in cancer genetics and is currently researching the clinical application of personal cancer genome sequencing at the Kinghorn Cancer Centre (Garvan Institute). He is also involved in targeted oncology testing at SydPath Pathology (St Vincent’s Hospital). Dr Mead is currently aConjoint Senior Lecturer at the School of Medical Sciences, University of NSW. DR CRAIG WALLINGTON-BEDDOE BSc (Hons), MB, BS (Hons), FRACP, FRCPA Speciality: Haematology Special interests: Malignant haematology, flow cytometry and molecular genetics Dr Craig Wallington-Beddoe graduated with a medical degree from the University of Sydney in 2001. During his early medical training, he developed an interest in haematology and undertook postgraduate clinical and laboratory haematology training at Prince of Wales and Westmead Hospitals for the awards of FRACP and FRCPA in 2010. Dr Wallington-Beddoe is currently completing his PhD studies in acute lymphoblastic leukaemia (ALL) research at the Westmead Millennium Institute, the University of Sydney. His study is investigating the function of enzymes called sphingosine kinases in maintaining viable ALL cells and attempting to exploit these enzymes and their associated intracellular signalling pathways to provide a novel approach to treating ALL. Dr Wallington-Beddoe joined Douglass Hanly Moir’s haematology department in November 2011. His interests are in malignant haematology, with a particular focus on leukaemias and lymphoid neoplasms, and he is familiar with a wide range of laboratory techniques and their applications to clinical haematology. DR MICHAEL WEHRHAHN BSc (Med), MB, BS (Hons), MPH (Hons), FRACP, FRCPA Specialty: Microbiology Special interests: Clinical infectious diseases and diagnostic microbiology After graduating from the University of NSW in 1999, Dr Michael Wehrhahn completed a Master of Public Health at the University of Sydney before commencing training in Clinical Microbiology and Infectious Diseases in Perth, in 2005. Experience gained at Royal Perth, Fremantle and Princess Margaret Hospitals was complemented by appointments at Liverpool, Royal North Shore and Westmead Hospitals, where he completed his training in mid-2011. Dr Wehrhahn has developed several specific interests and areas of expertise. For the last two years, he has worked as a clinical mentor to HIV providers in the Highlands of Papua New Guinea, in addition to maintaining research interests in the clinical and laboratory features of communityassociated MRSA, novel diagnostic methods for identifying fastidious bacteria and identifying preventable factors associated with health-care associated infections. He holds a current appointment as Adjunct Lecturer at the University of Notre Dame, Sydney. 4 Clostridium difficile Infection Clostridium difficile is an anaerobic Gram-positive, spore-forming bacillus, identified first as normal bowel flora in healthy neonates but, over time, recognised as a potential gastrointestinal pathogen of major clinical and cross-infection significance. Disease is related to the production of two potent exotoxins: toxin A ("enterotoxin") and toxin B ("cytotoxin"), which cause intestinal fluid secretion, mucosal injury and inflammation. Toxin B is the essential virulence factor of C. difficile, however, being approximately ten times more potent than toxin A. Dr Ian Chambers Microbiologist C. difficile is the causative organism of antibiotic-associated colitis and diarrhoea, and is a cause of significant morbidity (and occasional mortality) especially, but not exclusively, among hospitalized patients. Antibiotic administration is the most widely recognized risk factor for C. difficileassociated diarrhoea (CDAD) but other risk factors include hospitalization, advanced age, concurrent severe illness, chemotherapy etc. CDAD can also occur without any risk factor being identifiable. The main clinical features of C. difficile infection are watery diarrhoea, abdominal pain, low grade fever and leucocytosis, although the clinical spectrum ranges from asymptomatic carriage to severe fulminant disease and toxic megacolon. Illness is generally in the setting of current or recent antibiotic administration, but onset may be days or weeks after antibiotic treatment has stopped. The antibiotics most frequently implicated are fluoroquinolones, clindamycin, cephalosporins, and penicillins, but virtually all antibiotics, including metronidazole and vancomycin, have been associated with CDAD. Over the last decade, hospital-acquired C. difficile infection has become a major problem worldwide, with the incidence and severity of healthcare-associated disease increasing dramatically. Several factors are involved in this, including the high carriage rates of C. difficile in hospitalised adults (~30%) and its easy transmissibility via fomites. A more virulent strain of C. difficile has also emerged in that time. This strain (C. difficile ribotype 027) causes a more severe illness which can be refractory to standard therapy and is more likely to relapse than that caused by other strains. Its hypervirulence may be due to its substantially greater toxin production compared to conventional strains, and a strong correlation exists between its emergence and the increased use of fluoroquinolone antibiotics. 5 Clostridium difficile Infection Laboratory Tests for CDAD The two main approaches to the diagnosis of C. difficile infection are detection of the organism itself and detection of the toxin(s) it produces. Until recently no method with the necessary diagnostic sensitivity and specificity was also rapid, simple and inexpensive enough for routine use. Organism detection assays (including antigen testing and culture) have the inherent problem that some C. difficile strains are non-toxigenic. Up to 30 percent of hospitalized patients are colonized by C. difficile without having disease and therefore the presence of the organism by itself does not prove pathogenicity. Enzyme immunoassay (EIA) for either toxins A and B combined or toxin B alone is the method in widest use. While specificity is generally good and false-positives uncommon, the diagnostic sensitivity of these assays is only moderate and the falsenegative rate is unacceptably high. EIA should not be used for the investigation of possible CDAD. Polymerase Chain Reaction (PCR) provides greatly enhanced diagnostic sensitivity for CDAD. The tcdB gene of C. difficile (which encodes toxin B) is considered to be its primary virulence factor and is present in virtually all diarrhoeagenic strains, including the hypervirulent O27 ribotype. Detection of the tcdB gene by PCR provides rapid and accurate diagnosis, which in turn allows prompt implementation of treatment and infection control measures. PCR overcomes the disadvantages inherent in other methods and has recently been introduced at Douglass Hanly Moir Pathology for the diagnosis of CDAD. Several aspects of this assay should be emphasised 1 CDAD is associated with current or recent antibiotic administration and/or recent hospitalisation and testing for C. difficile is appropriate when such risk factors are present in an individual with diarrhoea. It is not a common cause of sporadic, community-acquired diarrhoeal illness in otherwise healthy individuals and testing for it should not be included in the initial laboratory investigations of such patients. 2 The tcdB PCR test is appropriate for use only on unformed stool from patients with clinically significant diarrhoea. Certain patient groups (eg current or recent hospital inpatients and infants in the first year of life) have high rates of asymptomatic carriage of toxigenic C. difficile and such individuals do not require treatment. Formed stool should only be tested in exceptional circumstances. 3 The high diagnostic sensitivity of the tcdB PCR provides reliable, single-sample diagnosis of CDAD. If an initial result is negative the diagnostic yield is not significantly increased by testing another specimen. 4 Nucleic acid remains detectable for several weeks after effective treatment for CDAD, making test-of-cure unnecessary and possibly misleading. An exception to this is in the context of relapsing illness. 5 If possible, specimens should be refrigerated until transported to the laboratory. Specimens are stable for up to 2 days at room temperature and 5 days if refrigerated at 4˚C. 6 Faecal specimens may occasionally contain factors which inhibit the PCR process. If such inhibition is found and cannot be resolved, repeat collection should be considered. PCR represents a major advance in the diagnosis of C.difficile-associated disease. Douglass Hanly Moir Pathology is pleased to be able to provide this test as the primary investigation for this condition. For further information, or to discuss a patient please contact Dr Ian Chambers or Dr Miriam Paul on 98 555 312 6 Parapertussis Bordetella parapertussis, like B. pertussis, is a recognised cause of whooping cough in all ages and, in some countries, causes up to one-third of whooping cough cases. The clinical presentation is similar to that of B. pertussis but is generally milder, with the majority of patients having a cough lasting less than a week and entire illness that resolves within a month. The “whoop” is a feature in up to 60% of cases and post-tussive vomiting in up to 40% of cases. Dr Michael Wehrhahn Microbiologist The reduced severity of parapertussis infection is thought to be related to a lack of key virulence factors, such as pertussis toxin (PT), that are found in B. pertussis. There is no cross immunity between pertussis and parapertussis and, as the components in the current pertussis vaccine target toxins like PT, the vaccine has limited, if any, protection against parapertussis. In those with severe disease caused by B. parapertussis, one can expect clinical improvement from the same antibiotics recommended for the treatment of B. pertussis. Integrated Cycler for detection of B. pertussis and B. parapertussis No data is available with regard to the value of prophylaxis for highrisk contacts of patients with B. parapertussis and it is not a notifiable disease, in contrast to B. pertussis. Child with whooping cough While culture, in the past, has been the main way of differentiating these two species, few laboratories in Australia still culture for B. pertussis/ parapertussis. At DHM, the recent introduction of a real-time multiplex PCR that detects B. pertussis and B. parapertussis simultaneously has allowed the diagnosis of an additional proportion of whooping cough cases. This test is performed Monday to Friday with a result expected within 24 hours. Diagnosis of parapertussis may prevent unnecessary further investigation of a patient’s cough illness and support the decision to treat with antibiotics. For further information, or to discuss a patient please contact Dr Michael Wehrhahn on 98 555 287 7 Chlamydia trachomatis infection Chlamydia trachomatis is the most commonly notified sexually transmissible bacterial disease in Australia, with annual casenotifications doubling since the early 1990s. It affects both genders, with approximately 75% of reported infections occurring in those aged less than 30 years. It is also the most common infective cause of pelvic inflammatory disease and subsequent female-factor infertility in Australian women. Several countries have instituted screening programs in asymptomatic young women to prevent such long-term complications of this infection. Risk factors for chlamydia infection include multiple sexual partners, a recent change in sexual partner and non-use of barrier contraceptives, such as condoms. Endocervical C. trachomatis infection has also been associated with an increased risk of acquiring HIV infection and may also increase HIV infectiousness. Dr Ian Chambers Microbiologist Mode of transmission This is predominantly by sexual contact, but occasionally from mother to baby during vaginal delivery. The high proportion of asymptomatic cases results in untreated infection, ongoing transmission and increased incidence of long-term sequelae. Diagnosis of genitourinary C. trachomatis infection RACGP guidelines recommend annual testing for all sexually active 15-25 year-olds, including those who are asymptomatic. Screening for chlamydia can be opportunistic, that is, when the patient presents for unrelated reasons. Polymerase Chain Reaction (or one of the other nucleic acid detection methods available) is the test of choice for diagnosing C. trachomatis and a variety of specimens can be suitable. The preferred specimen for Chlamydia testing in men is urine, rather than a urethral swab. A properly collected male urethral swab causes discomfort, which means that most male urethral swabs are not properly collected and give inferior results, compared to urine. The requirements for a first-void urine, as opposed to a mid-stream, and that an hour should have elapsed since last passing urine, have become more relaxed over time because of the very high sensitivity of the methods currently used for diagnosis. Urine is collected in the usual yellow-top urine jar. Urine is also an acceptable specimen for routine chlamydia testing in women, although if a speculum examination is being conducted, then a swab taken from the endocervix is recommended. 8 Testing for chlamydia in women can also be performed on a low vaginal swab. This does not require the use of a speculum and the swab can be self-collected by patients if they wish to do so. A dry swab (ie, a swab for which the transport tube contains no liquid medium) is recommended for chlamydia PCR. If available, a ‘flocked’ swab is better than a standard swab because it collects more material. Flocked swabs are available from the Stores department. If a ThinPrep liquid cytology vial has been collected, this specimen is also suitable for use in the C. trachomatis and N. gonorrhoeae PCR tests. Despite advice to the contrary from some professional groups, the growing incidence of gonorrhoea suggests that this diagnosis should also be considered when testing for C. trachomatis is undertaken. The same specimen can be used for both tests. Re-testing for C. trachomatis Test-of-cure is not usually recommended after treatment, except when the patient is pregnant or unless there is persistence of symptoms. Repeat testing is indicated, however, if there is a continuing risk of re-infection. Serology for C. trachomatis The diagnosis of genital chlamydia infection cannot be confirmed or excluded serologically. Serology has no useful role in this situation: it is not accurate and should not be done. Chlamydia trachomatis PCR is performed daily, using the Roche cobas 4800 instrument. Chlamydia trachomatis infection The Roche Cobas 4800 instrument automates C.trachomatis and N.gonorrhoeae PCR testing Coloured transmission electron micrograph (TEM) of Chlamydia trachomatis bacteria (purple) inside a cell (yellow). Magnification: x5000 when printed 10cm wide For further information, or to discuss a patient please contact Dr Ian Chambers or Dr Miriam Paul on 98 555 312 9 Rapid Identification of Bacterial Pathogens by MALDI-TOF Mass Spectroscopy Not many deliveries to Douglass Hanly Moir Pathology of large, shiny machines encased in bubble-wrap are addressed to the Microbiology Laboratory, but that day has come at last. Douglass Hanly Moir Pathology is the first private laboratory in Australia to begin using an instrument that is amongst the most sophisticated available for the rapid and reliable identification of bacterial and fungal pathogens. MALDI-TOF (Matrix-Assisted Laser Desorption Ionisation – Time of Flight) technology uses mass spectroscopy (MS) to analyse bacterial and fungal cultures. This not only allows much faster identification of potential pathogens, but provides greater certainty of that identification. Dr Ian Chambers Microbiologist Dr Michael Wehrhahn Microbiologist 10 MALDI-TOF-MS relies on the premise that virtually every bacterial species, when analysed using mass spectroscopy, has a unique “protein signature”, based on mass-charge ratio. Microbial identification is achieved by comparing the mass spectral profile of the test organism with a database consisting of more than 500 medically important bacteria and 70 relevant fungi. If the required level of concordance is reached between test and reference profiles, identification has been achieved. Routine use of this technology, over the last decade in Europe and more recently worldwide, has established its clinical utility. More rapid identification of pathogens (taking minutes rather than the 4-24 hours required by traditional identification methods) has translated into improved clinical outcomes. Rapid Identification of Bacterial Pathogens by MALDI-TOF Mass Spectroscopy Vitek MS: Faster identification of pathogens and improved management of sepsis. On average, it is anticipated that the identification and reporting of most organisms will take a day less than is currently possible. While formal antibiotic susceptibility testing is still required, rapid pathogen identification allows empiric antibiotic selection to be made with greater confidence and appropriate antibiotic selection leads to improved clinical outcomes. This is of greatest importance in critical conditions, such as bacteraemia and sterile-site infections, but treatment and outcomes of less critical conditions, such as soft-tissue and urinary tract infection, will also be improved. MALDI-TOF-MS will also shorten the time it takes to report uncommon and difficult-to-identify organisms which are currently sent to reference laboratories. In many cases, this will shorten the identification-time from a week or more to the same day the culture becomes positive. The introduction of MALDI-TOF-MS technology represents a fundamental shift in the approach to diagnostic microbiology. In an area of pathology where oxgall, rabbit plasma and fetal bovine serum are still essential reagents for the identification of bacteria and fungi, a shiny new machine is a welcome addition. For further information, or to discuss a patient please contact Dr Ian Chambers on 98 555 330 or Dr Michael Wehrhahn on 98 555 287 11 BARRATT & SMITH PATHOLOGY A trading name of DOUGLASS HANLY MOIR PATHOLOGY PTY LIMITED • ABN 80 003 332 858 A subsidiary of SONIC HEALTHCARE LIMITED • APA ABN 24 004 196 31 LAWSON STREET • PENRITH • NSW 2750 • AUSTRALIA TEL (02) 4734 6500 • FAX (02) 4732 2503 MAIL ADDRESS • PO BOX 443 • PENRITH • NSW 2751 • AUSTRALIA Co-brand-DNL-Winter2012-9737 DOUGLASS HANLY MOIR PATHOLOGY PTY LIMITED • ABN 80 003 332 858 A subsidiary of SONIC HEALTHCARE LIMITED • APA ABN 24 004 196 909 14 GIFFNOCK AVENUE • MACQUARIE PARK • NSW 2113 • AUSTRALIA TEL (02) 98 555 222 • FAX (02) 9878 5077 MAIL ADDRESS • LOCKED BAG 145 • NORTH RYDE • NSW 1670 • AUSTRALIA
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