Infectious Diseases &

Infection Control Infection Control

In DentistryIn Dentistry

Types of MicroorganismsTypes of Microorganisms

Pathogenic (causing disease)Pathogenic (causing disease) Potentially PathogenicPotentially Pathogenic Non-PathogenicNon-Pathogenic

Some infections only occur in individuals who Some infections only occur in individuals who are immunocompromised because their immune are immunocompromised because their immune system is unable to fight the potential pathogen. system is unable to fight the potential pathogen. These are called opportunistic infections.These are called opportunistic infections.

How do Infections Occur?How do Infections Occur?

PathogensPathogens VirusVirus BacteriaBacteria FungiFungi ProtozoaProtozoa RickettsiaRickettsia HelminthesHelminthes

Since a number of Since a number of diseases can be diseases can be transmitted during transmitted during routine dental care, it is routine dental care, it is important to understand important to understand the principles behind the principles behind the infection controlthe infection control

Body has normal resistance to most pathogens

How are diseases transmitted in the How are diseases transmitted in the dental setting?dental setting?

From the patient to the dental workerFrom the patient to the dental worker From the dental worker to the patientFrom the dental worker to the patient From one patient to anotherFrom one patient to another From the dental office to the communityFrom the dental office to the community Transmission can be…Transmission can be… DirectDirect- - from an infected person to another person from an infected person to another person

who iswho is not immunenot immune IndirectIndirect- - from contact with objects that are from contact with objects that are

contaminated, like surfaces or instruments contaminated, like surfaces or instruments DropletDroplet-from spray or splatter contact with mucous -from spray or splatter contact with mucous

membranes, or contact with aerosols (stay suspended membranes, or contact with aerosols (stay suspended in the air for longer periods of time)in the air for longer periods of time)

For Infection to Occur…For Infection to Occur…

PathogenPathogen

QuantityQuantity

VulnerabilityVulnerability

Entry Site/ModeEntry Site/Mode

The Process The Process of Infectionof Infection

1. Exposure

2. Infection

3. Incubation Period

4. ProdormalPeriod

5. Clinical Stage

6. Recovery orRelapse

7. Termination

Recommendations for Adult Recommendations for Adult ImmunizationsImmunizations

Diphtheria , Polyomyelitis , Tetanus Diphtheria , Polyomyelitis , Tetanus ( DPT ) ( DPT )

Hepatitis BHepatitis BHepatitis A ? ? ?Hepatitis A ? ? ?

Measles, Mumps and Rubella ( MMR )Measles, Mumps and Rubella ( MMR )Varicella (Chickenpox) ?Varicella (Chickenpox) ?Meningococcal Disease ? Meningococcal Disease ?

Influenza ? Influenza ? Pneumococcal Disease ?Pneumococcal Disease ?

Infectious Diseases for Infectious Diseases for DentistDentist

Common ColdCommon Cold InfluenzaInfluenza Herpes simplex Herpes simplex MononucleosisMononucleosis MeningitisMeningitis Group A and Group B Strep InfectionGroup A and Group B Strep Infection Staphylococcus aureus DiseasesStaphylococcus aureus Diseases TetanusTetanus AnthraxAnthrax New Infectious TreatsNew Infectious Treats

Common Cold FactsCommon Cold Facts

There are 200 distinct cold viruses.There are 200 distinct cold viruses.

Spring & Summer ColdsSpring & Summer Colds Rhinoviruses causing symptoms above the neckRhinoviruses causing symptoms above the neck

Stuffy nose, headache and runny nose.Stuffy nose, headache and runny nose.

Treatments for the Common ColdTreatments for the Common Cold

IbuprofenIbuprofen

AntihistaminesAntihistamines Watch for drowsinessWatch for drowsiness Individuals with hypertension , diabetes, Individuals with hypertension , diabetes,

heart disease, or thyroid disorders should heart disease, or thyroid disorders should limit products containing pseudoephedrine.limit products containing pseudoephedrine.

Influenza ( Flu ) Influenza ( Flu ) Facts Facts

The flu causes more severe, longer The flu causes more severe, longer lasting symptoms than a cold.lasting symptoms than a cold.

Influenza A and influenza B.Influenza A and influenza B.TransmissionTransmission The flu is very contagious and is spread The flu is very contagious and is spread

by coughs, sneezes, laughs, and even by coughs, sneezes, laughs, and even normal conversation.normal conversation.

Vaccinations : Vaccinations : AnnuallyAnnually

Antiviral DrugsAntiviral DrugsRelenza and TamifluRelenza and Tamiflu

Student Snapshot, p. 402

Individuals Who Should Get Individuals Who Should Get FluVaccineFluVaccine

Individuals aged 65 years and older.Individuals aged 65 years and older. Individuals aged 2 to 64 years with Individuals aged 2 to 64 years with

chronic health conditions.chronic health conditions. Children aged 6 to 23 months.Children aged 6 to 23 months. Pregnant women.Pregnant women. Health-care personnelHealth-care personnel Household contacts and caregivers.Household contacts and caregivers.

13

HerpesvirusesHerpesviruses

Large family; 8 infect humansLarge family; 8 infect humansHSV-1 –Herpes simplex 1 – Herpes Labialis , HSV-1 –Herpes simplex 1 – Herpes Labialis ,

WhitelowsWhitelowsHSV-2 –Herpes simplex 2 – Genetal Herpes , HSV-2 –Herpes simplex 2 – Genetal Herpes ,

EncephalitisEncephalitisVZV – Varicella zoster virus - Chicken VZV – Varicella zoster virus - Chicken

pox ,Shingles pox ,Shingles EBV – Epstein-Barr virus –I.M , Burkitt EBV – Epstein-Barr virus –I.M , Burkitt

LymphomaLymphomaHHV-6 –Herpevirus 6 –Roseola InfantumHHV-6 –Herpevirus 6 –Roseola InfantumHHV-7 –Herpevirus 7 - ? No disease HHV-7 –Herpevirus 7 - ? No disease

assocciationassocciationHHV-8 –Herpevirus 8 – Kaposi SarcomaHHV-8 –Herpevirus 8 – Kaposi Sarcoma

14

Oral-Facial HerpesOral-Facial Herpes Acute Gingivo stomatitisAcute Gingivo stomatitis

Acute gingivostomatitis is the commonest manifestation of Acute gingivostomatitis is the commonest manifestation of primary herpetic infection. primary herpetic infection.

The patient experiences pain and bleeding of the gums. 1 - The patient experiences pain and bleeding of the gums. 1 - 8 mm ulcers with necrotic bases are present. 8 mm ulcers with necrotic bases are present.

Neck glands are commonly enlarged accompanied by fever. Neck glands are commonly enlarged accompanied by fever. Usually a self limiting disease which lasts around 13 days. Usually a self limiting disease which lasts around 13 days.

Herpes labialis (cold sore) Herpes labialis (cold sore) Following primary infection, 45% of orally infected Following primary infection, 45% of orally infected

individuals will experience reactivation. The actual individuals will experience reactivation. The actual frequency of recurrences varies widely between individuals. frequency of recurrences varies widely between individuals.

Herpes labialis (cold sore) is a recurrence of oral HSV.Herpes labialis (cold sore) is a recurrence of oral HSV. A prodrome of tingling, warmth or itching at the site A prodrome of tingling, warmth or itching at the site

usually heralds the recurrence. About 12 hours later, red usually heralds the recurrence. About 12 hours later, red ness appears followed by papules and then vesicles. ness appears followed by papules and then vesicles.

H. Labialis ( Cold H. Labialis ( Cold Sore )Sore )

Herpetic whitlowsHerpetic whitlows

17

HHV – 6 : Roseala InfantumHHV – 6 : Roseala Infantum

HHV – 8 : Kaposi HHV – 8 : Kaposi SarcomaSarcoma

Originally isolated Originally isolated from cells of Kaposi’s from cells of Kaposi’s sarcoma (KS)sarcoma (KS)

Now appears to be Now appears to be firmly associated with firmly associated with Kaposi’s sarcoma Kaposi’s sarcoma

Most patients with KS Most patients with KS have antibodies have antibodies against HHV-8against HHV-8

20

Diagnosis, Treatment, and Diagnosis, Treatment, and Control of Herpes SimplexControl of Herpes Simplex

Vesicles and exudate are typical Vesicles and exudate are typical diagnostic symptomsdiagnostic symptoms

Scrapings from base of lesions showing Scrapings from base of lesions showing giant cellsgiant cells

Culture and specific tests for Culture and specific tests for diagnosing severe or disseminated HSVdiagnosing severe or disseminated HSV

Direct fluorescent antibody testsDirect fluorescent antibody tests Treatment:Treatment: Acyclovir, Famciclovir, Acyclovir, Famciclovir,

Valacyclovir; Topical medicationsValacyclovir; Topical medications

21

Parvoviruses . B . 19Parvoviruses . B . 19 B19 cause of erythema infectiosum (fifth B19 cause of erythema infectiosum (fifth

disease); rash of childhood disease); rash of childhood (“slapped (“slapped face” )face” ) Children may have fever and rash on Children may have fever and rash on

cheekscheeks Severe fatal anemia can result if Severe fatal anemia can result if

pregnant woman transmits virus to fetuspregnant woman transmits virus to fetus

Varicella Zooster VirusVaricella Zooster Virus Primary infection results in varicella (chickenpox) Primary infection results in varicella (chickenpox) Incubation period of 14-21 daysIncubation period of 14-21 days Presents fever, lymphadadenopathy. a widespread Presents fever, lymphadadenopathy. a widespread

vesicular rash.vesicular rash. The features are so characteristic that a diagnosis can The features are so characteristic that a diagnosis can

usually be made on clinical grounds alone.usually be made on clinical grounds alone. Complications are rare but occurs more frequently and Complications are rare but occurs more frequently and

with greater severity in adults and with greater severity in adults and immunocompromised patients.immunocompromised patients.

Most common complication is secondary bacterial Most common complication is secondary bacterial infection of the vesicles.infection of the vesicles.

Severe complications which may be life threatening Severe complications which may be life threatening include viral pneumonia, encephalititis, and include viral pneumonia, encephalititis, and haemorrhagic chickenpox.haemorrhagic chickenpox.

Varicella Zooster VirusVaricella Zooster Virus Varicella (chickenpox) and herpes zoster (shingles) are

distinct clinical entities cause by the varicella-zoster virus (VZV).

In young children, prodromal symptoms of chickenpox are uncommon, but in older children and adults, the manifestation of the rash may be preceded by two or three days of fever and chills, malaise, headache, backache, sore throat, and dry cough.

The rash begins on the face and scalp and spreads rapidly to the trunk, with relative sparing of the extremities.

New lesions arise in crops, usually appearing centrally. Each crop proceeds through the developmental phase described below, so that at any given time, a patient can have macules, papules, vesicles, pustules, and crusts. (Scarring is rare )

In smallpox, by contrast, at any given time, all lesions on the patient's body are in the same phase of development.

Chicken Pox - RashChicken Pox - Rash

Chicken Pox - RashChicken Pox - Rash

Differential Dx - Chickenpox

Chickenpox Begins on the face

and scalp, spreads to the trunk

Lesions in various stages of development can simultaneously be present on the patient's skin

Variola (Smallpox)

Begins centrally, then spreads outward to face and extremities

All lesions are always in a single stage of development

Treatment & Preventive Treatment & Preventive CareCare

More severe form in adultsMore severe form in adults May cause pneumonia, disseminated infection in adultsMay cause pneumonia, disseminated infection in adults HandwashingHandwashing Isolation of children from public places until Isolation of children from public places until

lesions are crusted and drylesions are crusted and dry Antivirals to lessen symptoms mostly in adultsAntivirals to lessen symptoms mostly in adults HCW with out past exposure to chickenpox may HCW with out past exposure to chickenpox may

consider chickenpox vaccineconsider chickenpox vaccine Varicella zoster immune globulin recommended Varicella zoster immune globulin recommended

if pregnant and with a substantial exposureif pregnant and with a substantial exposure

Herpes Zoster (Shingles)Herpes Zoster (Shingles) Herpes Zoster mainly affect a single dermatome of the skin. Herpes Zoster mainly affect a single dermatome of the skin. It may occur at any age but the vast majority of patients are more It may occur at any age but the vast majority of patients are more

than 50 years of age. than 50 years of age. The latent virus reactivates in a sensory ganglion and tracks The latent virus reactivates in a sensory ganglion and tracks

down the sensory nerve to the appropriate segment.down the sensory nerve to the appropriate segment. It is characterized by unilateral radicular pain and a vesicular

eruption that is typically limited to one or two dermatomes innervated by a spinal or cranial nerve.

The most distinctive characteristics of herpes zoster are its localization and it distribution, which is almost always unilateral.

There is a characteristic eruption of vesicles in the dermatome There is a characteristic eruption of vesicles in the dermatome which is often accompanied by intensive pain which may last for which is often accompanied by intensive pain which may last for months (postherpetic neuralgia)months (postherpetic neuralgia)

Herpes zoster affecting the eye and face may pose great Herpes zoster affecting the eye and face may pose great problems.problems.

As with varicella, herpes zoster in a far greater problem in As with varicella, herpes zoster in a far greater problem in immunocompromised patients in whom the reactivation occurs immunocompromised patients in whom the reactivation occurs earlier in life and multiple attacks occur as well as complications.earlier in life and multiple attacks occur as well as complications.

Complications are rare and include encephalitis and Complications are rare and include encephalitis and disseminated herpes zoster.disseminated herpes zoster.

Relationship between varicella Relationship between varicella and zosterand zoster

29

Herpes Zoster (Shingles)Herpes Zoster (Shingles)

31

Epstein-Barr Virus Epstein-Barr Virus (EBV)(EBV)

Transmission – direct, oral contact and Transmission – direct, oral contact and contamination with salivacontamination with saliva

In industrialized countries, college-age In industrialized countries, college-age population is vulnerable to infectious population is vulnerable to infectious mononucleosis (mono or kissing disease)mononucleosis (mono or kissing disease)

By mid-life, 90-95% of all people are infectedBy mid-life, 90-95% of all people are infected Infectious mononucleosis – sore throat, high Infectious mononucleosis – sore throat, high

fever, cervical lymphadenopathy; develop fever, cervical lymphadenopathy; develop after 30-50 day incubationafter 30-50 day incubation

Dormancy in B cells; reactivated; may be Dormancy in B cells; reactivated; may be asymptomaticasymptomatic

Disease AssociationDisease Association1. 1. Infectious MononucleosisInfectious Mononucleosis

2. Burkitt's lymphoma2. Burkitt's lymphoma

3. Nasopharyngeal carcinoma3. Nasopharyngeal carcinoma

4. Lymphoproliferative disease and lymphoma 4. Lymphoproliferative disease and lymphoma in the immunosuppressed.in the immunosuppressed.

5. Oral leukoplakia in AIDS patients5. Oral leukoplakia in AIDS patients

Infectious MononuclosisInfectious Mononuclosis Primary EBV infection is usually subclinical in childhood. Primary EBV infection is usually subclinical in childhood.

However in adolescents and adults, there is a 50% chance However in adolescents and adults, there is a 50% chance that the syndrome of infectious mononucleosis (IM) will that the syndrome of infectious mononucleosis (IM) will develop.develop.

IM is usually a self-limited disease which consists of fever, IM is usually a self-limited disease which consists of fever, lymphadenopathy and splenomegaly. In some patients lymphadenopathy and splenomegaly. In some patients jaundice may be seen which is due to hepatitis.jaundice may be seen which is due to hepatitis.

Atypical lymphocytes are present in the blood. Atypical lymphocytes are present in the blood. Complications occur rarely but may be serious e.g. splenic Complications occur rarely but may be serious e.g. splenic

rupture, meningoencephalitis, and pharyngeal rupture, meningoencephalitis, and pharyngeal obstruction.obstruction.

In some patients, chronic IM may occur where eventually In some patients, chronic IM may occur where eventually the patient dies of lymphoproliferative disease or the patient dies of lymphoproliferative disease or lymphoma.lymphoma.

Diagnosis of IM is usually made by the heterophil Diagnosis of IM is usually made by the heterophil antibody test and/or detection of EBV IgM.antibody test and/or detection of EBV IgM.

There is no specific treatment.There is no specific treatment.

34

Tumors Associated with Tumors Associated with EBVEBV

Burkitt lymphomaBurkitt lymphoma – B cell malignancy; – B cell malignancy; usually develops in jaw and grossly swells usually develops in jaw and grossly swells the cheek; central African children 4-8 years the cheek; central African children 4-8 years old; may be associated with chronic old; may be associated with chronic coinfections with malaria, etc.coinfections with malaria, etc.

Nasopharyngeal carcinomaNasopharyngeal carcinoma – malignancy – malignancy of epithelial cells; occurs in older Chinese of epithelial cells; occurs in older Chinese and African menand African men

Anyone with an immune deficiency is highly Anyone with an immune deficiency is highly susceptible to EBVsusceptible to EBV

Epstein-Barr VirusEpstein-Barr Virus

35

36

Diagnosis, Treatment, and Diagnosis, Treatment, and PreventionPrevention

Differential blood count shows Differential blood count shows lymphocytosis, neutropenia, and large lymphocytosis, neutropenia, and large atypical lymphocytes; serological assays to atypical lymphocytes; serological assays to detect antibodies and antigendetect antibodies and antigen

Treatment directed at relief of symptoms Treatment directed at relief of symptoms of fever and sore throatof fever and sore throat

Disseminated disease may be treated with Disseminated disease may be treated with IV gamma globulin, interferon, acyclovir, IV gamma globulin, interferon, acyclovir, and monoclonal antibodiesand monoclonal antibodies

Skin Structure Infections by Skin Structure Infections by SiteSiteSkin

Compartment

Epidermis

Dermis

Hair follicle

Subcutan. fat

Fascia

Muscle

(Pseudomonas aeruginosa)(Pseudomonas aeruginosa)

Clostridia,Clostridia, Strep. pyogenesStrep. pyogenesmyositis

Staphylococcus aureus : Staphylococcus aureus : DiseasesDiseases

Pyoderma : Pyoderma : pyogenesis in the (skin)pyogenesis in the (skin) Impetigo - multiple pustules with erythematous base on face and Impetigo - multiple pustules with erythematous base on face and

extremitiesextremities Furuncles - large, painful, nodules filled with pus and necrotic tissue = Furuncles - large, painful, nodules filled with pus and necrotic tissue =

boilboil Carbuncles - multiple boils which coalesce in deep subcutaneous tissueCarbuncles - multiple boils which coalesce in deep subcutaneous tissue Wound infections - erythrema, edema, pain in/around woundsWound infections - erythrema, edema, pain in/around wounds

BacteremiaBacteremia - bacteria in the blood from other infections - bacteria in the blood from other infections sitessites

OsteomyelitisOsteomyelitis - infection of highly vascularized area of bone - infection of highly vascularized area of bone EndocarditisEndocarditis - infection of the endocardium - infection of the endocardium Toxic shock syndromeToxic shock syndrome Scalded skin syndromeScalded skin syndrome Food poisoningFood poisoning

intoxicationintoxication PneumoniaPneumonia - response to the presence of bacteria in the - response to the presence of bacteria in the

lungslungs

Folliculitis, Furuncle, Carbuncle,and Cutaneous Abscess

Folliculitis is characterized by the formation of a circumscribed, conical pustule around a hair follicle.

A furuncle is a deep, necrotizing form of folliculitis, with pus accumulation. Several furuncles may coalesce to form a carbuncle.

A carbuncle is larger than a furuncle, typically occurring at the nape of the neck or on the back or thighs. The lesion is red, indurated, painful, and multiple pustules soon appear on its surface, draining around multiple hair follicles. The lesion develops a yellow-gray crater at the center and heals slowly by granulation.

An abscess (boil) is a localized accumulation of purulent material deep in the dermis or subcutaneous tissue. Pus may not be visible on the surface of the skin. An abscess is warm, red, and tender; it frequently begins as folliculitis.

Most furuncles and carbuncles are caused by Staphylococcus aureus. Fever and malaise sometimes accompany carbuncles and abscesses.

A furuncle starts as a hard, tender, red nodule in hair-bearing skin that enlarges and becomes painful and fluctuant. Rupture may occur with drainage of pus. The pain then subsides, and the redness and swelling subside over several days or weeks.

ImpetigoImpetigo

Furuncle

Carbuncle

Streptococcus pyogenesStreptococcus pyogenes Group A Streptococcal DiseasesGroup A Streptococcal Diseases PharyngitisPharyngitis- suppurative erythematous inflammation of the - suppurative erythematous inflammation of the

pharynxpharynx sore throat with exudate and cervical lymphadenopathysore throat with exudate and cervical lymphadenopathy accompanied by fever, malaise and headacheaccompanied by fever, malaise and headache also known as “strep throat”also known as “strep throat”

Scarlet feverScarlet fever - pharyngitis with diffuse erythematous rash on - pharyngitis with diffuse erythematous rash on head/extremhead/extrem

rash blanches when pressed, raw red tongue= strawberry rash blanches when pressed, raw red tongue= strawberry tonguetongue

no rash around mouth or palms/solesno rash around mouth or palms/soles PyodermaPyoderma - purulent(pus forming) lesions on face, arms, and - purulent(pus forming) lesions on face, arms, and

legslegs vesicles fill with pus, rupture, and crust overvesicles fill with pus, rupture, and crust over

ErysipelasErysipelas - acute infection of the skin with fever, chills, - acute infection of the skin with fever, chills, leukocytosisleukocytosis

inflamed areas is distinctly raised from uninfected skininflamed areas is distinctly raised from uninfected skin CellulitisCellulitis - localized inflammation of subcutaneous tissues - localized inflammation of subcutaneous tissues

accompanied by fever, chills, leukocytosisaccompanied by fever, chills, leukocytosis

Streptococcus pyogenesStreptococcus pyogenes Group A Streptococcal DiseasesGroup A Streptococcal Diseases Necrotizing fasciitisNecrotizing fasciitis - infection of deep subcutaneous tissues - infection of deep subcutaneous tissues

extensive destruction muscle(gangrene) and fatextensive destruction muscle(gangrene) and fat spreads along facial planesspreads along facial planes often results in systemic toxicity, organ failure, and deathoften results in systemic toxicity, organ failure, and death

Streptococcal toxic shock syndromeStreptococcal toxic shock syndrome – multi system toxicity – multi system toxicity begins with localized soft tissue inflammation and painbegins with localized soft tissue inflammation and pain accompanied by fever, chills, malaise, vomitting, diarrheaaccompanied by fever, chills, malaise, vomitting, diarrhea toxicity causes liver, heart, and lungs to failtoxicity causes liver, heart, and lungs to fail patient is bacteremic and often has necrotizing faciitispatient is bacteremic and often has necrotizing faciitis

BacteremiaBacteremia - beta hemolytic streptococci in the blood - beta hemolytic streptococci in the blood accompanies necrotizing faciitis and toxic shock syndromeaccompanies necrotizing faciitis and toxic shock syndrome does not occur with pharyngitis, pyoderma, or erysipelasdoes not occur with pharyngitis, pyoderma, or erysipelas

Rheumatic feverRheumatic fever - nonsuppurative sequalae to group A Strep - nonsuppurative sequalae to group A Strep infectioninfection

inflammatory changes in heart, joints, blood vessels, and subcutaneousinflammatory changes in heart, joints, blood vessels, and subcutaneous chronic progressive damage to the heart valves often occurschronic progressive damage to the heart valves often occurs

GlomerulonephritisGlomerulonephritis - nonsuppurative sequalae to group A Strep - nonsuppurative sequalae to group A Strep infectioninfection

acute inflammation of glomeruliacute inflammation of glomeruli accompanied by edema, hypertension, hematuria, and proteinuriaaccompanied by edema, hypertension, hematuria, and proteinuria

ImpetigoImpetigo

Group A streptococcus, Staphylococcus Group A streptococcus, Staphylococcus arueusarueus

Superficial blistersSuperficial blistershoney colored crusts honey colored crusts on erythematous baseon erythematous base

No systemic signsNo systemic signs Mainly in childrenMainly in children May be associated with May be associated with

glomerulonephritisglomerulonephritis Treat with penicillin/antistaphylococcal Treat with penicillin/antistaphylococcal

penicillinpenicillin

CellulitisCellulitis

Deeper infection usually involving skin Deeper infection usually involving skin and subcutaneous tissueand subcutaneous tissue

Erythema, pain and swelling often with Erythema, pain and swelling often with distinct border (erysipelas)distinct border (erysipelas)

Fever and lymphangitis or adenitis Fever and lymphangitis or adenitis commoncommon

Gp A streptococcus, Staphylococcus Gp A streptococcus, Staphylococcus aureus most commonaureus most common

Treat with antistaphylococcal penicillin Treat with antistaphylococcal penicillin unless culture positiveunless culture positive

Necrotizing FasciitisNecrotizing Fasciitis

Streptococcal gangrene (Gp A strept)Streptococcal gangrene (Gp A strept) Deeper infection involving fascia and Deeper infection involving fascia and

often muscleoften muscle Extreme toxicity and rapid spread (“flesh-Extreme toxicity and rapid spread (“flesh-

eating virus”)eating virus”) May have associated toxic shockMay have associated toxic shock Treatment – surgical removal of necrotic Treatment – surgical removal of necrotic

tissue and antibioticstissue and antibiotics Penicillin and clinidamycinPenicillin and clinidamycin

Streptococcus pyogenesStreptococcus pyogenes Diagnosis of Streptococcal DiseasesDiagnosis of Streptococcal Diseases SymptomsSymptoms

Pharyngitis - with or without tonsillar exudatePharyngitis - with or without tonsillar exudate Fever, rash, inflammation or swellingFever, rash, inflammation or swelling

Laboratory TestsLaboratory Tests Gram stain from specimen or cultureGram stain from specimen or culture CultureCulture Antigen detection (microantigen)Antigen detection (microantigen)

Detect group specific C-carbohydrate in throat culturesDetect group specific C-carbohydrate in throat cultures React antigen with antibody bound to membrane or latex React antigen with antibody bound to membrane or latex

particlesparticles Antibody detectionAntibody detection

Anti-streptolysin O (ASO test) indicates recent( 3-4 wks) Anti-streptolysin O (ASO test) indicates recent( 3-4 wks) streptococcal infection and helps confirm rheumatic fever or streptococcal infection and helps confirm rheumatic fever or acute glomerulonephritisacute glomerulonephritis

Anti-DNase B - helps confirm pyoderma or pharyngitis Anti-DNase B - helps confirm pyoderma or pharyngitis associated with glomerulonephritisassociated with glomerulonephritis

Characteristics of PharyngitisCharacteristics of PharyngitisAgent Exudate Lymph

nodesTreatment

Gp A strept + Submandibular

Penicillin

Viral - + None

C. Diphtheriae

Membrane “Bull neck” AntitixonErythromycin, Penicillin

Infectious mononucleosis

+ Diffuse None

Food PoisoningFood PoisoningAgent Mechanism Incubation Clinical

S. Aureus Enterotoxin 1-8 h Nausea, vomiting, diarrhea

B. Cereus Toxin 4 h Diarrhea

Clostridium perfirngens

Sporulation toxin

8-16 h Diarrhea

Salmonella 12-48 h Fever, pain and diarrhea

Infectious DiarrheaInfectious Diarrhea

FeverFever

EnterotoxinEnterotoxin

E. ColiE. Coli --

V. choleraeV. cholerae --

Invasive Invasive

SalmonellaSalmonella ++

ShigellaShigella ++

C. jejuniC. jejuni ++

E. coli O157:H7E. coli O157:H7 ++

Y. EnterocoliticaY. Enterocolitica ++

Meningitis - An Emergency

Etiology•Viral•Pneumococcus•Haemophilus influenzae•Meningococcus•Listeria•Coccidioides immitis

Diagnosis•LP•Blood cultures (BEFORE antibiotics) - very

important•CT scan in selected patients

MENINGOCOCCAL MENINGITISMENINGOCOCCAL MENINGITIS

Meningococcal DiseasesMeningococcal Diseases PreventionPrevention

Eradicate the pool of healthy carriersEradicate the pool of healthy carriers those identified can be treated prophylactically those identified can be treated prophylactically

with antibioticswith antibiotics also exposed susceptible(s) can be treated also exposed susceptible(s) can be treated

chemoprophylacticallychemoprophylactically polysaccharide vaccines exist for some polysaccharide vaccines exist for some

serogroupsserogroups TreatmentTreatment

Antibiotic treatment if started earlier can Antibiotic treatment if started earlier can alter the course of the diseasealter the course of the disease mortality approaches 100% in untreated casesmortality approaches 100% in untreated cases Penicillin(s) are currently agents of choicePenicillin(s) are currently agents of choice antibiotic resistant strains have begun to occurantibiotic resistant strains have begun to occur

Viral infections of the Viral infections of the (CNS)(CNS)

Clinical syndromeClinical syndrome Part of CNS Part of CNS affectedaffected

EncephalitisEncephalitis Brain ParenchymaBrain Parenchyma

Aseptic meningitisAseptic meningitis MeningesMeninges

MyelitisMyelitis Spinal CordSpinal Cord

NeuritisNeuritis Peripheral NervesPeripheral Nerves

LethargySudden fever

Vomiting and diarrhea

Tremors or convulsions

Headache Change in consciousness

Irritability or restlessness

Common symptoms of Encephalitis

Encephalitis vs.V. Encephalitis vs.V. MeningitisMeningitis

EncephalitisEncephalitisViral Viral

MeningitisMeningitis

Constitutional symptomsConstitutional symptoms

FeverFever YesYes YesYes

Headache, nausea, vomiting, Headache, nausea, vomiting, lethargylethargy

YesYes YesYes

Photophobia, neck stiffnessPhotophobia, neck stiffness No No YesYes

Neurologic dysfunctionNeurologic dysfunction

SeizuresSeizures YesYes MinimalMinimal

Cranial nerve palsies, paralysisCranial nerve palsies, paralysis YesYes NoNo

Altered mental status (i.e. Altered mental status (i.e. confusion, coma)confusion, coma)

YesYes MinimalMinimal

Differentiating Viral from Differentiating Viral from BacterialBacterial

Viral MeningitisViral Meningitis CSF clear to cloudy CSF clear to cloudy ↑↑ initial pressure initial pressure ↑↑ protein protein normal glucose normal glucose ↑↑ cells (not over cells (not over

1000/mcL, polys on day 1000/mcL, polys on day 1, then more lymphs) 1, then more lymphs)

a specific virus is a specific virus is incriminated by rising incriminated by rising titer after patient is titer after patient is betterbetter

Bacterial Bacterial MeningitisMeningitis CSF clear to purulent CSF clear to purulent ↑↑ initial pressure initial pressure ↑↑ protein protein ↓↓ glucose glucose ↑↑ polys (often more than polys (often more than

1000/mcL) 1000/mcL) ↑↑ lymphs (some, typically lymphs (some, typically

after treatment) after treatment) positive gram stain, positive gram stain,

culture, and/or culture, and/or meningitis antigens meningitis antigens

New Infectious ThreatsNew Infectious Threats Severe Acute Severe Acute

Respiratory Syndrome Respiratory Syndrome (SARS)(SARS)

Avian FluAvian Flu Swine FluSwine Flu

Bioterror ThreatsBioterror Threats AnthraxAnthrax SmallpoxSmallpox BotulismBotulism TularemiaTularemia

Anthrax – Bacillus anthracisAnthrax – Bacillus anthracis Gram positive, spore-forming rod with capsule Gram positive, spore-forming rod with capsule

,Spores in soil, or animal products,Spores in soil, or animal products Enter through skin, alimentary, respiratory Enter through skin, alimentary, respiratory

tractstracts Toxin: (cyclase), lethal factorToxin: (cyclase), lethal factor Painless ulcer with marked local edemaPainless ulcer with marked local edema Pneumonia (mediastinitis) Pneumonia (mediastinitis) meningitismeningitis Necrotizing enteritisNecrotizing enteritismeningitismeningitis Diagnosis-cultureDiagnosis-culture Treatment: Treatment:

ciprofloxacin+clindamycin+rifampin, penicillin ciprofloxacin+clindamycin+rifampin, penicillin if susceptibleif susceptible

Cutaneous Anthrax

TETANUSTETANUS Diseases caused by Clostridium tetaniDiseases caused by Clostridium tetani Incubation period is usually 3-21 days.Incubation period is usually 3-21 days.

tetanustetanus maximum sustained contraction of skeletal maximum sustained contraction of skeletal musclesmuscles Generalized most common form involving masseter muscles, Generalized most common form involving masseter muscles,

back contractions, cardiac arrhythmias, profuse sweatingback contractions, cardiac arrhythmias, profuse sweating Cephalic : primary site of infection is the headCephalic : primary site of infection is the head Localized : symptoms confined to musculature at site of infectionLocalized : symptoms confined to musculature at site of infection Death is most often due to paralysis of the respiratory muscles.Death is most often due to paralysis of the respiratory muscles.

Basis of VirulenceBasis of Virulence TetanospasminTetanospasmin

Neurotoxin blocks release of inhibitory neurotransmitters Neurotoxin blocks release of inhibitory neurotransmitters causing unregulated excitatory synaptic activity in motor nervescausing unregulated excitatory synaptic activity in motor nerves

plasmid-encoded, heat labileplasmid-encoded, heat labile A-B toxin, released upon cell lysis, binds irreversiblyA-B toxin, released upon cell lysis, binds irreversibly

TetanolysinTetanolysin oxygen-labile hemolysinoxygen-labile hemolysin

TETANUSTETANUSMODE OF TRANSMISSIONMODE OF TRANSMISSION1.1. Tetanus spores are introduced into the Tetanus spores are introduced into the

body, usually through a puncture wound body, usually through a puncture wound contaminated with soil or feces.contaminated with soil or feces.

2.2. Incubation period of usually 3-21 days.Incubation period of usually 3-21 days.

DIAGNOSISDIAGNOSIS• The diagnosis of tetanus is made by The diagnosis of tetanus is made by

observation of uncontrolled contraction of observation of uncontrolled contraction of skeletal muscle, following puncture wounds, skeletal muscle, following puncture wounds, burns, or trauma to body parts. burns, or trauma to body parts.

• The organism is rarely recovered from the The organism is rarely recovered from the site of infection, and usually there is not site of infection, and usually there is not detectable antibody response.detectable antibody response.

TETANUSTETANUS Prevention of TetanusPrevention of Tetanus

Proper treatment of deep puncture woundsProper treatment of deep puncture wounds clean and disinfect the woundclean and disinfect the wound stop the bleedingstop the bleeding keep aerobickeep aerobic

ImmunizationImmunization basis in artificial active immunitybasis in artificial active immunity vaccine contains tetanus toxoidvaccine contains tetanus toxoid inactive/antigenic inactive/antigenic

tetanospasmintetanospasmin given in the polyvalent vaccine, DPT or DTgiven in the polyvalent vaccine, DPT or DT

Treatment of TetanusTreatment of Tetanus Antitoxin (TIG). Antitoxin (TIG). Artificial passive Artificial passive

immunityimmunity AntibioiticAntibioitic

IMMUNIZATIONSIMMUNIZATIONS

1.1. Vaccination series for 1 to 3 month Vaccination series for 1 to 3 month old babies consists of 3 injections old babies consists of 3 injections given 2 months apart as part of DPT.given 2 months apart as part of DPT.

2.2. A booster dose about 1 and 4 years A booster dose about 1 and 4 years later.later.

3.3. Children immunized have protection Children immunized have protection for 10 years.for 10 years.

4.4. Additional booster dose every 10 Additional booster dose every 10 years.years.

Botulinum Food PoisoningBotulinum Food Poisoning Diseases caused by Clostridium botulinumDiseases caused by Clostridium botulinum

Botulism: bilateral descending weakness of Botulism: bilateral descending weakness of peripheral muscles terminating with respiratory peripheral muscles terminating with respiratory paralysisparalysis

other symptoms = Blurred vision, dry mouth, other symptoms = Blurred vision, dry mouth, constipation, abdominal painconstipation, abdominal pain

Food borne intoxicationFood borne intoxication Wound botulismWound botulism same symptoms same symptoms

due to infection in soil contaminated woundsdue to infection in soil contaminated wounds

Basis of VirulenceBasis of Virulence botulinum toxin(s)botulinum toxin(s)

binds specifically to cholinergic nervesbinds specifically to cholinergic nerves blocks the release of acetylcholine at peripheral synapsesblocks the release of acetylcholine at peripheral synapses A-B toxin with seven antigenic variants- A, B, E, F, are most A-B toxin with seven antigenic variants- A, B, E, F, are most

commoncommon binds irreversiblybinds irreversibly

Clostridium botulinumClostridium botulinum Epidemiology of botulismEpidemiology of botulism

common source food borne poisoning of the intoxication common source food borne poisoning of the intoxication typetype

commonly associated with water-based canned foodscommonly associated with water-based canned foods home canned foods account for 85% of botulism caseshome canned foods account for 85% of botulism cases commercially canned foods for 15% of botulism casescommercially canned foods for 15% of botulism cases

some cases involve other types of foodssome cases involve other types of foods Prevention of botulismPrevention of botulism

sterilization of water-based canned foodssterilization of water-based canned foods freezingfreezing avoid giving honey to infantsavoid giving honey to infants

Treatment of botulismTreatment of botulism Botulism antitoxins, A, B, E,Botulism antitoxins, A, B, E, artificial passive immunityartificial passive immunity Gastric lavageGastric lavage

Clostridium perfringens : Gas Clostridium perfringens : Gas GangreneGangrene

Diseases/Infections involving Clostridium Diseases/Infections involving Clostridium perfringensperfringens Gas gangrene (myconecrosis) : Extensive muscle necrosisGas gangrene (myconecrosis) : Extensive muscle necrosis Soft tissue infections(cellulitis) : Organism grows in the fascial Soft tissue infections(cellulitis) : Organism grows in the fascial

planesplanes Food poisoning :Abdominal cramps and diarrheaFood poisoning :Abdominal cramps and diarrhea Necrotizing enteritis : Acute necrosis of the jejunumNecrotizing enteritis : Acute necrosis of the jejunum SepticemiaSepticemia : Generally not significant : Generally not significant

Basis of VirulenceBasis of Virulence alpha toxin : Lecithinase, hemolytic, >vascular permeabilityalpha toxin : Lecithinase, hemolytic, >vascular permeability

a lecithinase, zinc metallophospholipase, hydrolyzes the a lecithinase, zinc metallophospholipase, hydrolyzes the phosphatylcholine and sphingomyelin in eucarytoic cell membrane phosphatylcholine and sphingomyelin in eucarytoic cell membrane = cell death= cell death

Clostridium group A toxin responsible for myonecrosisClostridium group A toxin responsible for myonecrosis beta toxin : Necrosis, causes release of catecholaminebeta toxin : Necrosis, causes release of catecholamine iota toxin : Necrosis and increased vascular permeabilityiota toxin : Necrosis and increased vascular permeability Enterotoxin : Cytotoxic, alters membrane permeabilityEnterotoxin : Cytotoxic, alters membrane permeability

Clostridium perfringensClostridium perfringens EpidemiologyEpidemiology

Portal of EntryPortal of Entry integument via wounds, integument via wounds, gastrointestinal tract via ingestion of endosporesgastrointestinal tract via ingestion of endospores

ExampleExample meat, fish, or poultry containing endospores meat, fish, or poultry containing endospores is cooked; spores are not killed; food is incubated at is cooked; spores are not killed; food is incubated at warm(room) temperature and spores germinate; if food warm(room) temperature and spores germinate; if food is not adequately reheated, vegetative cells are is not adequately reheated, vegetative cells are ingested and sporulate in the intestine; This sporulation ingested and sporulate in the intestine; This sporulation process releases the enterotoxinprocess releases the enterotoxin

PreventionPrevention rapid and adequate treatment of woundsrapid and adequate treatment of wounds

debridementdebridement keep aerobickeep aerobic

refrigerate high risk foods to prevent spores from refrigerate high risk foods to prevent spores from germinatinggerminating

Clostridium difficileClostridium difficile Diseases caused by Clostridium difficileDiseases caused by Clostridium difficile

antibiotic associated colitisantibiotic associated colitis antibiotic associated pseudomembranous colitisantibiotic associated pseudomembranous colitis

Basis of VirulenceBasis of Virulence enterotoxinenterotoxin - stimulates neutrophil chemotaxis, cytokine release - stimulates neutrophil chemotaxis, cytokine release

with accompanying inflammation, hypersecretion of fluid, and with accompanying inflammation, hypersecretion of fluid, and hemorrhagic necrosishemorrhagic necrosis

cytotoxin - depolymerizes actin, thus destroying the cellular cytotoxin - depolymerizes actin, thus destroying the cellular cytoskeletoncytoskeleton

adhesin factoradhesin factor mediates binding to colonic cells, esp ileummediates binding to colonic cells, esp ileum hyaluronidasehyaluronidase hydrolyzes intestinal hyaluronic acidhydrolyzes intestinal hyaluronic acid spore formationspore formation past for long term survivalpast for long term survival

Epidemiology of Antibiotic-associated enterocolitisEpidemiology of Antibiotic-associated enterocolitis This is an example of opportunismThis is an example of opportunism

Clostridium difficile is part of the normal microflora in many healthy and Clostridium difficile is part of the normal microflora in many healthy and hospitalized peoplehospitalized people

In most people it is sufficiently antagonized and its endospores are latentIn most people it is sufficiently antagonized and its endospores are latent Many antibiotics, especially those taken orally, kill the antagonistic Many antibiotics, especially those taken orally, kill the antagonistic

microflora, thus allowing this organism to germinate and growmicroflora, thus allowing this organism to germinate and grow PreventionPrevention

This condition is difficult to preventThis condition is difficult to prevent The organism is common in hospitalsThe organism is common in hospitals Antibiotics are necessary to control other infectionsAntibiotics are necessary to control other infections

MucormycosisMucormycosis

DM (DKA), leukemia/neutropenia, DM (DKA), leukemia/neutropenia, transplant, deferoxamine therapytransplant, deferoxamine therapy

Rhinocerebral MucormycosisRhinocerebral Mucormycosis Fever, sinus/facial pain/edema, H/A, Fever, sinus/facial pain/edema, H/A,

CN palsies, retinal vein thrombosis, CN palsies, retinal vein thrombosis, cavernous sinus thrombosiscavernous sinus thrombosis

Surgical debridement & Surgical debridement & Amphotericin B: Posaconazole (60% Amphotericin B: Posaconazole (60% response rate)response rate)