pPstpPst 9.5 kb- smallest plasmid9.5 kb- smallest plasmid

Found only in Found only in Y. PestisY. Pestis

Encodes for plasminogen activator (Encodes for plasminogen activator (pla)pla)

Cell surface proteaseCell surface protease

Has coagulase activity evident only at temperatures Has coagulase activity evident only at temperatures below 30°C, which initiates blockage in flea and forms below 30°C, which initiates blockage in flea and forms fibrin matrix that anchors bacteria to proventiculus of fibrin matrix that anchors bacteria to proventiculus of fleaflea

At 37°C exhibit fibronolytic activities, lyses fibrin at bite At 37°C exhibit fibronolytic activities, lyses fibrin at bite site and allows dissemination of bacteriumsite and allows dissemination of bacterium

pPstpPst Other possible functions of Plasminogen Other possible functions of Plasminogen

activatoractivator

Produces excess plasmin that causes ineffective Produces excess plasmin that causes ineffective structures between inflammatory cells and fibrinstructures between inflammatory cells and fibrin

Reduces chemoattractants at the infection site Reduces chemoattractants at the infection site possibly via inhibition of IL-8.possibly via inhibition of IL-8.

Encodes bacteriosin pesticin (Encodes bacteriosin pesticin (pstpst) and its ) and its immunity protein (immunity protein (pimpim))

pCD1pCD1 68-75 kb68-75 kb (depending on the strain) (depending on the strain)

Responsible for encoding anti-host genomeResponsible for encoding anti-host genome

Y.PestisY.Pestis, , Y.pseudotuberculosisY.pseudotuberculosis, and , and Y. EnterocolitisY. Enterocolitis both both possess this plasmidpossess this plasmid

Encodes the Low Calcium Response System (LCRS)- Encodes the Low Calcium Response System (LCRS)- controlled by Temperature and Calcium concentrationcontrolled by Temperature and Calcium concentration

Low Calcium response V antigen-LcrVLow Calcium response V antigen-LcrV Yersinia Outer membrane proteins- YopsYersinia Outer membrane proteins- Yops Specific Yop chaperones- SycSpecific Yop chaperones- Syc Yop secretion proteins/Type III secretion system- YscYop secretion proteins/Type III secretion system- Ysc

pCD1pCD1LcrV/V antigenLcrV/V antigen

LcrV protein plays a role in regulating the LCRSLcrV protein plays a role in regulating the LCRS

It is a protective antigen that is associated with It is a protective antigen that is associated with resistance to phagocytosisresistance to phagocytosis

May play an immunosuppressive role, by inhibiting May play an immunosuppressive role, by inhibiting cytokine productioncytokine production

Induces IL-10 production by macrophages this Induces IL-10 production by macrophages this downregulates host’s immune responsedownregulates host’s immune response

pCD1pCD1Yop proteinsYop proteins

Altogether there are 29 Yop proteinsAltogether there are 29 Yop proteins

Yop effector proteins protect Yop effector proteins protect Y.pestisY.pestis from from macrophages by destroying phagocytic signaling macrophages by destroying phagocytic signaling capabilitiescapabilities

There are 6 Yops which directly or indirectly cause There are 6 Yops which directly or indirectly cause disease:disease: Yop E, Yop H, Yop J, Yop O, Yop M, Yop B and D Yop E, Yop H, Yop J, Yop O, Yop M, Yop B and D

How Yops Thwart How Yops Thwart Host Immune SystemHost Immune System

■ ■ Yop EYop E■ ■ Indirectly depolymerizes actin Indirectly depolymerizes actin

microfilamentsmicrofilaments

■ ■ Yop HYop H■■ a protein tyrosine a protein tyrosine

phosphatase capable of phosphatase capable of dephosphorylating host dephosphorylating host proteins such as p125proteins such as p125FAKFAK and and p130p130CaCa at focal adhesions, at focal adhesions, inhibiting signal transduction inhibiting signal transduction necessary for phagocytosis necessary for phagocytosis

■ ■ Yop JYop J■■ Binds to MAP kinase family-Binds to MAP kinase family-

downregulating TNF-downregulating TNF-

More YopsMore Yops Yop O/YpkAYop O/YpkA

Ser/Thr kinase that Ser/Thr kinase that probably interferes with probably interferes with signaling pathwayssignaling pathways

Yop MYop M Prevents thrombin platelet Prevents thrombin platelet

aggregationaggregation Mutes inflammatory Mutes inflammatory

response by sequestering response by sequestering thrombinthrombin

Yop B and DYop B and D Translocate effectors Translocate effectors

across cell membraneacross cell membrane

Yops RegulationYops RegulationTemperature and CaTemperature and Ca2+2+

When placed in 37°C and in a medium deprived of CaWhen placed in 37°C and in a medium deprived of Ca2+,2+, Y. PestisY. Pestis ceases growth and expression of Yops is ceases growth and expression of Yops is induced.induced.

Yops expression and secretion is induced in CaYops expression and secretion is induced in Ca2+2+--containing media by a local signal that occurs at the site containing media by a local signal that occurs at the site of contact between the pathogen and the eukaryotic cell. of contact between the pathogen and the eukaryotic cell. This leads to the polarized transfer of at least five Yops This leads to the polarized transfer of at least five Yops into the target cell.into the target cell.

pCD1pCD1Syc proteinsSyc proteins

Small Yop binding proteinsSmall Yop binding proteins

Not all Yops are syc associatedNot all Yops are syc associated

Act as chaperones by preventing Yop degradationAct as chaperones by preventing Yop degradation

Act as “secretion pilots” leading the Yops to their location Act as “secretion pilots” leading the Yops to their location of secretionof secretion

pCD1pCD1Ysc/ Type III secretion systemYsc/ Type III secretion system

Yops is mediated by Type III secretion Yops is mediated by Type III secretion system called Yscsystem called Ysc

Ysc Type III secretion system consists Ysc Type III secretion system consists of:of:

the core Ysc mechanism for secretion the core Ysc mechanism for secretion through the two bacterial membranes through the two bacterial membranes

a delivery apparatus (YopB, YopD, a delivery apparatus (YopB, YopD, YopK, LcrV)YopK, LcrV)

control elements (LcrE also called control elements (LcrE also called YopN and TyeA at the surface and YopN and TyeA at the surface and LcrG in the cytosol) LcrG in the cytosol)

anti-host effector proteins (YopE, anti-host effector proteins (YopE, YopH, YopM, YpkA and YopJ).YopH, YopM, YpkA and YopJ).

Ysc/Type III secretion systemYsc/Type III secretion system

YersiniaYersinia’s Deadly Kiss’s Deadly Kiss

All Together Now!All Together Now!

Clinical AspectsClinical AspectsFocus on Bubonic PlagueFocus on Bubonic Plague

Signs and symptomsSigns and symptomsComplicationsComplicationsDifferential DiagnosisDifferential DiagnosisDiagnosisDiagnosisTreatmentTreatmentPrognosisPrognosisPrevention Prevention Vaccine DevelopmentVaccine Development

Presenting Plague PatientsPresenting Plague Patients

%

Signs & SymptomsSigns & SymptomsWithin 2-7 days of Infection:

■ Severe malaise or prostration ---75%

■ High fever, headache ---20%-85%

■ Chills --- 40%

■ Vomiting ---25%-49%

■ Altered mentation ---26%-38%

■ Abdominal pain --- 18%

■ Other: bladder distention, apathy, confusion, fright, anxiety, oliguria, anuria, tachycardia, hypotension, leukocytosis

Signs & SymptomsSigns & Symptoms6-8 hours following onset of symptoms:

■ Pain/tenderness at regional lymph nodes enlarge to be called buboes

- extremely painful - occur in groin*, axilla or cervical areas - usually occur in 1 region, but multiple can be seen - may drain pus if left untreated

■ ulcer or skin lesions at site of flea bite <10% of cases

■ 2 Septicemic Plague due to hematogenous spread (23% of patients)

ComplicationsComplications

diffuse, hemorrhagicchanges in skin (darkened skin changes ="black death”)

Purpuric lesions

Acral necrosis

- Purpuric Lesions

- Acral Necrosis

- DIC disseminated intravascular coagulation

- Convulsions

- Shock

■ 2 Pneumonic Plague (5-15% of patients)

- begins as interstitial pneumonitis; bacteria in interstitium - show signs and symptoms prior to developing advanced pneumonitis:

High fever Severe bronchopneumonia Chest pain Coughing or spitting up blood Difficulty breathing

■ Infection of Buboes

■ Meningitis (< 5%)

■ Death

ComplicationsComplications

Sudden onset of fever, chills, headache, body pains, weakness, chest discomfort & tightness; Coughing with sputum production; Difficulty breathing; Coughing or spitting up blood; GI symptoms; Pharyngitis

Distinguishing 1 from 2 Pneumonic Plague

■ no buboes

■ 1-3 day incubation period

■ infectious pneumonitis from onset of symptoms

■ sputum production common

■ less severe evidence of disease in organs other than lungs

■ bacteria in alveoli

■ tracheal & bronchial mucosal hemorrhages

■ can lead to 2 Septicemic Plague

symptoms

■ no buboes

■ 1-4 day incubation period

■ more GI symptoms

■ can also lead to 2 Pneumonic Plague (25%)

■ meningitis is 4x more common

Fever and chills Extreme exhaustion Bleeding disorder Necrosis of small vessels Hemorrhagic Skin lesions (purpuric lesions, acral necrosis)Gangrene of extremities (nose or digits)DICConvulsionsShock

Distinguishing 1 from 2Septicemic Plague

symptoms

Differential DiagnosisDifferential Diagnosis

■ Streptococcal or staphylococcal adenitis

■ Tularemia

■ Cat scratch disease

■ Mycobacterial infection

■ Lymphogranuloma venereum

■ Chancroid

■ Primary genital herpes

■ 1 or 2 syphilis

■ Strangulated inguinal hernias

Bubonic Plague