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| __NOTOC__ | | __NOTOC__ |
| {{Listeriosis}} | | {{Listeriosis}} |
| {{CMG}} | | {{CMG}}; {{AE}} {{JS}} |
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| ==Overview== | | ==Overview== |
| The diagnosis should be established based on the clinical findings, complemented by culture of the organism from [[blood culture|blood]] and [[CSF]]. In many reported cases, despite the presence of the disease, [[CSF]] cultures were negative, in which cases, blood cultures should orient the diagnosis, since these are more commonly positive than the first ones.<ref name="pmid8507761">{{cite journal| author=Armstrong RW, Fung PC| title=Brainstem encephalitis (rhombencephalitis) due to Listeria monocytogenes: case report and review. | journal=Clin Infect Dis | year= 1993 | volume= 16 | issue= 5 | pages= 689-702 | pmid=8507761 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8507761 }} </ref>
| | Additional studies for the diagnosis of listeriosis are not recommended. |
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| ==Other Laboratory Studies== | | ==Other Laboratory Studies== |
| The methods for analysis of food are complex and time-consuming. The present [[Food and Drug Administration]] (FDA) method, revised in September, 1990, requires 24 and 48 hours of enrichment, followed by a variety of other tests. Total time for identification takes from 5 to 7 days, but the announcement of specific nonradiolabled [[DNA]] probes should soon allow a simpler and faster confirmation of suspect isolates.
| | Additional studies for the diagnosis of listeriosis are not recommended. |
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| Recombinant DNA technology may even permit 2-to-3 day positive analysis in the future. Currently, the FDA is collaborating in adapting its methodology to quantitate very low numbers of the organisms in foods.
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| ===CSF analysis===
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| [[CSF]] analysis may lead to the confirmation of listeriosis. Common findings include:
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| *[[Pleocytosis]]
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| *More than 25 [[lymphocytes]] in [[CSF]] [[Differential blood count (patient information)|differential count]], without [[antibiotic]] therapy.
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| *Moderately elevated [[CSF]] [[protein]] concentration with reduced [[CSF]] [[glucose]] concentration.<ref name="pmid9772921">{{cite journal| author=Mylonakis E, Hohmann EL, Calderwood SB| title=Central nervous system infection with Listeria monocytogenes. 33 years' experience at a general hospital and review of 776 episodes from the literature. | journal=Medicine (Baltimore) | year= 1998 | volume= 77 | issue= 5 | pages= 313-36 | pmid=9772921 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9772921 }} </ref>
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| * [[Gram stain]] of the [[CSF]] has very low [[sensitivity]] and even when organisms are seen, they may be misidentified. <ref name="pmid4998254">{{cite journal| author=Lavetter A, Leedom JM, Mathies AW, Ivler D, Wehrle PF| title=Meningitis due to Listeria monocytogenes. A review of 25 cases. | journal=N Engl J Med | year= 1971 | volume= 285 | issue= 11 | pages= 598-603 | pmid=4998254 | doi=10.1056/NEJM197109092851103 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4998254 }} </ref> Therefore, ''Listeria monocytogenes'' should always be considered when similar organisms are growing in [[blood culture |blood]] or [[CSF]] cultures. The presumptive diagnosis of [[viral meningitis]] should also be carefully considered in [[immunocompromised]], chronically ill, or elderly patients, presenting with acute [[meningitis]] and a negative [[Gram stain]]. Due to the fact that rhombencephalitis patients [[CSF]] examination often reveals only mild abnormalities, its diagnosis is often delayed.
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| *A [[Polymerase chain reaction]] assay has been developed for the ''hly gene'' detection, which encodes for the ''listeriolysin O'', in [[CSF]] cultures. However, despite more [[Specificity|specific]] and more [[sensitivity|sensitive]], it is not commercially available yet.
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| * Despite the name "monocytogenes", more that half the patients have increased levels of [[neutrophils]] in [[CSF]].
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| ===Stool cultures===
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| Stool cultures are not indicated in systemic [[listeriosis]] patients, since routine culture media for enteric [[pathogens]] are not appropriate for the growth of ''Listeria''. However, in cases of outbreaks of [[listeriosis]] or individual patients with suspected ''listerial'' [[gastroenteritis]], special selected media can be used. The special culture media may be suggested by a local [[microbiology]] laboratory, a state health department or the [[CDC]].
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| ===Serodiagnosis===
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| Diagnosis of [[listeriosis]] with [[antibodies]] for ''listeriolysin O'' have proven useful for diagnosis of [[infected]] patients with noninvasive disease<ref>{{Cite book | last1 = Mandell | first1 = Gerald L. | last2 = Bennett | first2 = John E. (John Eugene) | last3 = Dolin | first3 = Raphael. | title = Mandell, Douglas, and Bennett's principles and practice of infectious disease | date = 2010 | publisher = Churchill Livingstone/Elsevier | location = Philadelphia, PA | isbn = 0-443-06839-9 | pages = }}</ref>.
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| ===Imaging studies===
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| Although both [[MRI]] and [[CT]] scan may be used to help in the diagnosis of ''Listeria monocytogenes'' lesions, the MRI is a more [[sensitivity|sensitive]] method to detect ''listerial'' lesions in the cerebellum, brainstem and cortex.<ref name="pmid8507761">{{cite journal| author=Armstrong RW, Fung PC| title=Brainstem encephalitis (rhombencephalitis) due to Listeria monocytogenes: case report and review. | journal=Clin Infect Dis | year= 1993 | volume= 16 | issue= 5 | pages= 689-702 | pmid=8507761 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8507761 }} </ref> On an [[MRI]], in the [[cerebral]] [[parenchyma]] there may be identified high-signal lesions on T2-weighted images and enhancing lesions on T1-weighted images, following administration of IV contrast.
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| Since MRI evidence of brainstem involvement, coupled with proper clinical setting, is strongly suggestive of infection by ''Lysteria'', it is recommended the use of contrast [[MRI]] in all patients presenting with ''listerial'' [[meningitis]], ''listerial'' [[bacteremia]], [[CNS]] signs and symptoms or suspicion of intracranial [[listeriosis]].
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| [[Image:LSA.jpg|right|thumb|200px|Colonies of typical ''Listeria monocytogenes'' as they appear when grown on ''Listeria''-selective [[agar]]]]
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| ===Anton Test===
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| * A test used in the identification of [[Listeria monocytogenes]]
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| * Instillation of a culture into the conjunctival sac of a rabbit or guinea pig causes severe keratoconjunctivitis within 24 hours.<ref>{{cite web|url=http://medical-dictionary.thefreedictionary.com/Anton+test |title=Anton test - definition of Anton test in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia |publisher=Medical-dictionary.thefreedictionary.com |accessdate=2013-08-05}}</ref><ref>{{cite web|url=http://www.whonamedit.com/synd.cfm/197.html |title=Anton's eye test |publisher=Whonamedit |accessdate=2013-08-05}}</ref>
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| ===Cell Culture===
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| * Listeria grows on media such as Mueller-Hinton agar.<ref>Chapter 13. Non-Spore-Forming Gram-Positive Bacilli: Corynebacterium, Propionibacterium, Listeria, Erysipelothrix, Actinomycetes, & Related Pathogens ,Jawetz, Melnick, & Adelberg's Medical Microbiology, 24th Edition ,The McGraw-Hill Companies</ref>
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| * Identification is enhanced if the primary cultures are done on agar containing sheep blood, because the characteristic small zone of [[hemolysis]] can be observed around and under colonies.
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| * Isolation can be enhanced if the tissue is kept at 4°C for some days before inoculation into bacteriologic media.
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| * The motility at room temperature and hemolysin production are primary findings that help differentiate listeria from coryneform bacteria.
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| ==References== | | ==References== |
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| {{Reflist|2}} | | {{Reflist|2}} |
| [[Category:Bacterial diseases]]
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| [[Category:Disease]]
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| [[Category:Infectious disease]]
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| {{WH}} | | {{WH}} |
| {{WS}} | | {{WS}} |
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| | [[Category:Emergency mdicine]] |
| | [[Category:Disease]] |
| | [[Category:Up-To-Date]] |
| | [[Category:Infectious disease]] |
| | [[Category:Neurology]] |
| | [[Category:Gastroenterology]] |