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by Rebecca Ava Borja
Case 46
Female 21 years old
Migrant farm worker
27 weeks pregnant
Fever Headache Chills Frequent urination Decreased appetite Diarrhea Decreased fetal movement Abdominal tenderness Tachycardia Right costovertebral tenderness Stillborn infant delivered vaginally
Chest clear on auscultation No cervical discharge or tenderness on pelvic examination WBC: 21,300/uL LCR for C. trachomatis was (-) Ampicillin-subactam and gentamicin started
Patient HistorySymptoms Tests/Results
Case Summary
Pregnant migrant farm worker
Fever, headache, chills, diarrhea Right costovertebral tenderness Abdominal pain and tenderness
Pregnant migrant farm worker
Fever, headache, chills, diarrhea Right costovertebral tenderness Abdominal pain and tenderness
Intrauterine fetal demise – stillborn infant
Patient started on Ampicillin-subactam and Gentamicin
WBC of 21,300/uL
Key Symptoms
Key Symptoms
Gram (+) rod shaped bacteria
Clear, colorless, beta-hemolytic, raised colonies
Diagnosis
What is the suspected organism?
Listeria Monocytogenes
Classification of the organism:
- Small gram (+) rods that may appear pleomorphic.
- Non-spore former- Umbrella motility at
room temperature, motile by polar flagella at 370 C
Biochemical tests for isolation:
- CAMP - 6.5% NaCl
- Catalase - TSI: A/A- Esculin Hydrolysis
Where does it live?- Soil and water
How do you get it?- Eating
contaminated food,water,
unpasteurized dairyproducts, and raw
meat.- It is possible that
thepatient acquired theorganism while
workingin the farm.
What disease(s) can it cause?
- Listeriosis
Common Listeriosis symptoms:
Fever Muscle ache Gastrointestinal symptoms
(nausea or diarrhea) Headache Stiffneck Monocytosis
For pregnant women:
Stillbirth Premature delivery Infection of the newborn
Common Listeriosis symptoms:
Fever Muscle ache Gastrointestinal symptoms
(nausea or diarrhea) Headache Stiffneck Monocytosis
For pregnant women:
Stillbirth Premature delivery Infection of the newborn
Patient checklist:
DiagnosisWhy Listeriosis?
Pathogenesis
Virulence Factors:- Growth at low temperature
This allows it to grow in food stored in refrigerator.- Motility
At 20-25 0C, it uses its flagella to swim against the bowels’ peristaltic movement and to pierce the mucosal lining into which they attach. At 37 0C, it moves between and into host cells by polymerization of host cell actin at one end of the bacterium, which can propel it throughout the cytoplasm. This is one of the organisms’ special characteristics for spreading.
- Monocytosis producing agentThis lipid causes monocytosis in the cell; WBC
count greater than 950/uL. Patient had a WBC of 21,300/uL – shows possible monocytosis.
Pathogenesis
- Listeriolysin or LLO A toxin that forms pores to help the pathogen escape from endosome to the cytosol.- Internalins or InA Possibly mediates invasion; surface proteins that helps to introduce pathogen in epithelial cells. - ActA
Surface protein that helps the pathogen to propel on adjacent cell by rearrangement of actin.
- PhospholipaseAlso helps the pathogen in escaping endosome to the cytosol.
Pathogenesis
Mechanism of Invasion
Who is susceptible to Listeriosis?– Pregnant women are more susceptible in acquiring
this disease - 20 times more likely than other healthy adults.
– Newborns other than pregnant women themselves suffer the serious side effects of infection from pregnancy.
– Immunocompromised and elderly patients can easily get this disease.
Who is susceptible to Listeriosis?– Pregnant women are more susceptible in acquiring
this disease - 20 times more likely than other healthy adults.
– Newborns other than pregnant women themselves suffer the serious side effects of infection from pregnancy.
– Immunocompromised and elderly patients can easily get this disease.
Pathogenesis
Treatment and Prevention
AntibioticsAmpicillin is the antibiotic of choice against L.
monocytogenes and Gentamicin is frequently added for its synergistic effects. This is another hint from the case that the patient has listeriosis because she was started on Ampicillin-subactam and Gentamicin.
Prevention Handwashing before eating Avoiding deli meat, soft cheeses, and unpasteurized
dairy products Thoroughly cooking raw food from animal sources Washing raw vegetables before eating Consuming perishable goods as soon as possible Education and knowledge of Listeriosis especially for
pregnant women
Primary Literature
Ability of Listeria Monocytogenes Phospolipase C to facilitate escape from the macrophage phagosome is
dependent on host Protein Kinase CMathilde A. Poussin a,1, Michael Leitges b,2, Howard Goldfine a,*
a Department of Microbiology, School of Medicine, University of Pennsylvania, 19104-6076 Philadelphia, USA
b Signal Transduction Laboratory, Department of Nephrology, Medical School Hannover, Carl-Neuberg-Str.1, 30625 Hannover, GermanyIntroduction
L. monocytogenes is a facultative intracellular pathogenic bacteria that also infects macrophages and phagocytes. After entry in the host cell, the bacteria escapes from the phagosome to the cytoplasm. From previous research by the same group, it was found that pharmacological inhibition of Protein Kinase C resulted in significant reduction of phagosome permeabilization by L. monocytogenes. Why and how?
MethodsBone marrow macrophages obtained from PKC knockout and PKC
producing mice were infected with L. monocytogenes. A strain of L. monocytogenes lacking LLO was also introduced in
both but different
Primary Literature
sets of bone marrow macrophages.Results
The absence of LLO inhibited the organisms’ escape.
L. monocytogenes enters and escapes the phagosome with the same efficiency in PKC KO (Fig B) and PKC producing mice (Fig A). This indicates that host PKC is not essential for the escape of the organism.
However, the escape of Phospolipase C is not reduced in PKC KO mice. These findings strongly support the hypothesis that Phospolipase C promotes escape from the phagosome of macrophages through redistribution of host PKC.
sets of bone marrow macrophages. Conclusion
Bacterial PLC promotes escape through the production of diacylglycerol leading to the activation of host PKC. These findings suggest that L. monocytogenes PI-PLC through the formation of diacylglycerol activates a pathway that affects endosomal recycling pathways, which could interfere with phagosome maturation.
This concludes that Phospholipase C promotes escape through mobilization of host PKC.
Future goalA better understanding of signaling pathways in these cells.
References
Brouwer MC, van de Beek D, Heckenberg SG, Spanjaard L, & de Gans J.
(2006). Community-acquired Listeria monocytogenes meningitis in
adults. Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America. 43(10), 1233-8.
Cone LA, Somero MS, Qureshi FJ, Kerkar S, Byrd RG, Hirschberg JM, &
Gauto AR. (2008). Unusual infections due to Listeria monocytogenes
in the Southern California Desert. International Journal of Infectious Diseases : IJID : Official Publication of the International Society for Infectious Diseases. 12(6), 578-81.
Delgado AR. (2008). Listeriosis in pregnancy. Journal of Midwifery & Women's
Health. 53(3), 255-9.
Goulet V, Hedberg C, Le Monnier A, & de Valk H. (2008). Increasing incidence
of listeriosis in France and other European countries. Emerging Infectious Diseases. 14(5), 734-40.
References
Poussin, MA, Leitges M, Goldfine H. (2009). The ability of Listeria monocytogenes PI- PLC to facilitate escape from the macrophage phagosome is dependent on host PKCb. Journal of Microbial Pathogenesis. 46(1), 1-5.
And thank you for Dr. McQueens’ informative lecture slides regarding Listeria Monocytogenes for some of the pictures and key information.