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.