ANAEROBIC BACTERIAANAEROBIC BACTERIA

Dr- Fawzia Al-otaibi

DEFENITIONDEFENITION

A MICRBE THAT CAN ONLY GROW UNDER A MICRBE THAT CAN ONLY GROW UNDER ANAROBIC CONDITION ANAROBIC CONDITION

SENSETIVE TO SENSETIVE TO

metronidazole (MTZ)metronidazole (MTZ)

FAIL TO GROW IN AIR 10 % OFAIL TO GROW IN AIR 10 % O22

Why can’t anaerobic bacteria survive Why can’t anaerobic bacteria survive in oxygen?in oxygen?

The presence of oxygen leads to the production The presence of oxygen leads to the production in cells of the in cells of the superoxide radical superoxide radical (a negatively (a negatively charged O2 molecule). Normally, the superoxide charged O2 molecule). Normally, the superoxide anion is anion is lethallethal enough to kill almost any enough to kill almost any organism. Aerobic organisms and facultative organism. Aerobic organisms and facultative anaerobes have the enzymes anaerobes have the enzymes superoxide superoxide dismutase and catalasedismutase and catalase. These enzymes work . These enzymes work together to convert superoxide to oxygen and together to convert superoxide to oxygen and hydrogen peroxidehydrogen peroxide

CLASSIFICATIONCLASSIFICATION

A -NON SPORE FORMINGNA -NON SPORE FORMINGN

{MOR COMMN}{MOR COMMN}

B - SPORE FORMINGB - SPORE FORMING

A - NON SPORINGA - NON SPORING

A –A –GRAM NEGATIVE BACILLIGRAM NEGATIVE BACILLI bacteroides fragilis bacteroides fragilis ( resistant ( resistant

to penicillin)to penicillin) Prevotella sppPrevotella spp Leptotricha buccalisLeptotricha buccalis fusobacterium spp fusobacterium spp

f.nucleatumf.nucleatum Viellonella sp.Viellonella sp. GRAM NEGATIVE COCCiGRAM NEGATIVE COCCi

BB – –GRAME POSITIVE COCCIGRAME POSITIVE COCCIPeptococciPeptococciPeptostreptococciPeptostreptococci

CC – –GRAME POSITIVE BACILLIGRAME POSITIVE BACILLIPropionobacterium propionicum ,p.acnePropionobacterium propionicum ,p.acneBifidobacteriumBifidobacteriumEuobacteriumEuobacteriumLACTOBACILLUSLACTOBACILLUSActinomyces israeliiActinomyces israelii

DD--MICROAEROPHILIC STREPT.MICROAEROPHILIC STREPT.

BACTEROIDESBACTEROIDES

GROUP = GROUP = B. FRAGILIS, B. FRAGILIS, B. VULGARIS, B. VULGARIS, B.THETAIOTAMICRON, B. UNIFORMISB.THETAIOTAMICRON, B. UNIFORMIS– ACCOUNT FOR 1/3 OF ALL ISOLATESACCOUNT FOR 1/3 OF ALL ISOLATES– RESISTANT TO 20% BILERESISTANT TO 20% BILE– RESISTANT TO MANY ANTIBIOTICSRESISTANT TO MANY ANTIBIOTICS

PENICILLIN, KANAMYCIN, VANCOMYCIN, PENICILLIN, KANAMYCIN, VANCOMYCIN, COLISTIN – AND MANY MORECOLISTIN – AND MANY MORE

– NO PIGMENTATION NO PIGMENTATION OF COLONIES OR OF COLONIES OR FLUORESCENCEFLUORESCENCE

  

BACTEROIDES BACTEROIDES OTHER SPOTHER SP

BACTEROIDES SPECIES OTHER BACTEROIDES SPECIES OTHER THAN B. FRAGILIS GROUPTHAN B. FRAGILIS GROUP– BILE SENSITIVEBILE SENSITIVE– RESISTANT TO KANAMYCIN ONLYRESISTANT TO KANAMYCIN ONLY– SOME PIGMENTEDSOME PIGMENTED

SPORE FORMING SPORE FORMING

GRAME POSITIVE BACILLIGRAME POSITIVE BACILLICL .perfringensCL .perfringensCL .SepticumCL .SepticumCL .novyiCL .novyiCL .HistolyticumCL .HistolyticumCL .DifficileCL .DifficileCL .TetaniCL .TetaniCL .BotulinumCL .Botulinum

IMPORTANCEIMPORTANCE

Dominate the indigenous flora Dominate the indigenous flora (colonization resistance)(colonization resistance)

Commonly found in infectionCommonly found in infection

Easy to overlookEasy to overlookspecial precautionsspecial precautionsSlow growthSlow growthMixed infectionMixed infection

Difficult treatment Difficult treatment

PRESENCE AS NORMAL PRESENCE AS NORMAL FLORA FLORA

SkinSkinNoseNoseMouth, throatMouth, throatStomachStomachLarge intestine >10Large intestine >101111 / gram colonic / gram colonic contentscontentsVaginaVaginaEndocervixEndocervixUrethraUrethra

MODEFIED BY MODEFIED BY

Pathophysiologic statesPathophysiologic states

Antimicrobial agents ,H-Antimicrobial agents ,H-Blockers ,antacidsBlockers ,antacids

Hormonal changesHormonal changes

AgeAge

EPIDEMIOLOGYEPIDEMIOLOGY

Almost all infections are indigenous Almost all infections are indigenous except except TetanusTetanusInfant ,wound botulismInfant ,wound botulismGas gangrene { some cases }Gas gangrene { some cases }BitesBitesC .difficile {nosocomial }C .difficile {nosocomial }

HABITATHABITAT : :

These organism are normal flora in:These organism are normal flora in:

OropharynxOropharynx Provetella melaninogenicusProvetella melaninogenicus. Fusobacteria, . Fusobacteria,

Veillonella Veillonella Gastrointestinal tractGastrointestinal tract– Found mainly in the Found mainly in the large colon large colon in large numbersin large numbers– Total number of anaerobes = Total number of anaerobes = 10 10 1111

– While all aerobes (including E. While all aerobes (including E. coli) = coli) = 10 10 44

– examples are examples are (1) (1) Bacteroides fragilis Bacteroides fragilis – Bifidobacterium speciesBifidobacterium speciesFemale genital tract (mainly in the vagina) Female genital tract (mainly in the vagina)

CHARACTER OF ANAEROBIC CHARACTER OF ANAEROBIC INFECTIONINFECTION

SuppurationSuppuration

Abscess formationAbscess formation

Tissue destruction{gangrene}Tissue destruction{gangrene}

Septic thrombophlebitisSeptic thrombophlebitis

Some have unique pathology Some have unique pathology ActinomycosisActinomycosis

Psedomembranous colitisPsedomembranous colitis

Gas gangreneGas gangrene

PREDISPOSING FACTORSPREDISPOSING FACTORS

Low O tension {Eh}Low O tension {Eh}

Trauma, dead tissue , deep Trauma, dead tissue , deep woundwound

Impaired blood supplyImpaired blood supply

Presence of other organismsPresence of other organisms

Foreign bodiesForeign bodies

A 43-year-old man A 43-year-old man with surgically with surgically proved pyogenic proved pyogenic brain abscess in the brain abscess in the right basal ganglion right basal ganglion secondary to secondary to Eubacterium lentumEubacterium lentum (obligate anaerobe) (obligate anaerobe) infection. infection.

Axial contrast-Axial contrast-enhanced T1-enhanced T1-weighted MR image weighted MR image shows a ring-shaped shows a ring-shaped cystic lesion and cystic lesion and surrounding edema. surrounding edema.

Predisposing factors Predisposing factors Antibiotic therapy Antibiotic therapy

Neoplasm Neoplasm 

Trauma Trauma

Cholecystitis        Cholecystitis       

Obstruction  Obstruction  

Ulceration Ulceration

Diabetes mellitus  Diabetes mellitus  

PylephlebitisPylephlebitis

Diverticula formationDiverticula formation  

INFECTIONS BEGIN :INFECTIONS BEGIN :

DISRUPTION OF BARRIERS DISRUPTION OF BARRIERS – TRAUMATRAUMA– OPERATIONSOPERATIONS– CANCEROUS INVASION OF TISSUESCANCEROUS INVASION OF TISSUES

DISRUPTION OF BLOOD SUPPLYDISRUPTION OF BLOOD SUPPLY– DROPS OXYGEN CONTENT OF TISSUEDROPS OXYGEN CONTENT OF TISSUE– DECREASE IN Eh POTENTIALDECREASE IN Eh POTENTIAL– TISSUE NECROSISTISSUE NECROSIS

LABORATORY DIAGNOSIS:LABORATORY DIAGNOSIS:

When anaerobic infection is suspected;When anaerobic infection is suspected;a) Specimens have to be collected from a) Specimens have to be collected from

the site containing necrotic tissue.the site containing necrotic tissue.b) Pus is better than swabs.b) Pus is better than swabs.c) Specimens has to be send to the c) Specimens has to be send to the

laboratory within 1/2 hour why?laboratory within 1/2 hour why?d) Fluid media like cooked meat broth are d) Fluid media like cooked meat broth are

the best culture media.the best culture media.e) Specimens have to incubated e) Specimens have to incubated

anaerobically for 48 hours.anaerobically for 48 hours.

ACTINOMYCOSISACTINOMYCOSIS

Actinomyces are branching anaerobic or Actinomyces are branching anaerobic or microaerophilic microaerophilic Gram positive bacilliGram positive bacilliSource of the infection is normal flora and the Source of the infection is normal flora and the host usually normal hosthost usually normal hostPrimary site of the infection is mouth, lung, Primary site of the infection is mouth, lung, appendix, uterus with IUD (chronic infection)appendix, uterus with IUD (chronic infection)Infection can spread to the brain, liver, bone Infection can spread to the brain, liver, bone and bloodand bloodDiagnosis by Gram stain with sulfur granules Diagnosis by Gram stain with sulfur granules and growth of molar tooth coloniesand growth of molar tooth coloniesTreatment penicillin, clindamycin or Treatment penicillin, clindamycin or tetracycline tetracycline

TREATMENT:TREATMENT:

Bacteroides fragilisBacteroides fragilis is always is always resistant to penicillin.resistant to penicillin.

But penicillin can he used for other But penicillin can he used for other anaerobesanaerobes

Flagyl (metronidazole) is the drug of Flagyl (metronidazole) is the drug of choice. choice.

Clindamycin can also be used.Clindamycin can also be used.

TETANUSTETANUS

TRIMUSTRIMUSLOCKJAW 1884LOCKJAW 1884Strict toxigenic Strict toxigenic

diseasedisease

EPIDEMIOLOGYEPIDEMIOLOGY

1 Million/year > 60 yr .injection of 1 Million/year > 60 yr .injection of drugs {young}drugs {young}

½ due to neonatal tetanus½ due to neonatal tetanus

Cryptogenic t. {23%}Cryptogenic t. {23%}

Disease of non-immunized animals Disease of non-immunized animals and humans {toxoid}and humans {toxoid}

SOURCESOURCE

Animals feaces {horses} ,soil Animals feaces {horses} ,soil Contaminated wound {minor}Contaminated wound {minor}Compound fractureCompound fractureNarcotic addictsNarcotic addictsUnsterile injectionsUnsterile injectionsBurns , bites ,avulsionsBurns , bites ,avulsionsUmbilical stumpUmbilical stump

Face , neck , upper extremities wounds Face , neck , upper extremities wounds are more dangerousare more dangerous

TETANUSTETANUS

PATHOGENESISPATHOGENESISEXTOXIN EXTOXIN

{TETANOSPASMIN}{TETANOSPASMIN}Presynaptic Presynaptic

terminals of LMN terminals of LMN Inhibitory impulses Inhibitory impulses to MNsto MNs

Persistent tonic Persistent tonic spasmspasm

Clinical pictureClinical pictureGeneralizedGeneralizedLocalizedLocalizedCephalicCephalicNeonatal{ >90%}Neonatal{ >90%}

mortalitymortalityIP 3-21 daysIP 3-21 days

TRATMENTSupportive

AirwayMuscle relaxantWound care

AntitoxinAntibiotics :MTZ , PGTIG {500 UNITS}

PREVENTIONComplete active childhood immunizationAppropriate wound management

Type of woundImmunization history

DIAGNOSISClinicalLaboratory

{minor role}

C. PerfringensC. Perfringens{C.Welchii}{C.Welchii}

Histotoxic clostridiaHistotoxic clostridiaGas gangreneGas gangrene

Food PoisoningFood Poisoning

NATURAL HABITATSNATURAL HABITATS

Soil and intestinal tracts of animals and Soil and intestinal tracts of animals and humans { 10humans { 103 3 10 108 8 } }

Widespread occurrenceWidespread occurrence

Vagina of 1-9 % healthy womenVagina of 1-9 % healthy women

CLINICAL SIGNIFICANCECLINICAL SIGNIFICANCE

Species most commonly isolated from clinical Species most commonly isolated from clinical specimens specimens

Many clinical settings ranging from :-Many clinical settings ranging from :-Simple contamination of wounds – traumatic or non traumatic Simple contamination of wounds – traumatic or non traumatic myonecrosismyonecrosis

C. CellulitisC. Cellulitis

Intra-abdominal sepsisIntra-abdominal sepsis

Gangrenous cholecystitisGangrenous cholecystitis

Post-abortion infections – septicemiaPost-abortion infections – septicemia

BacteremiaBacteremia

Brain abscess Brain abscess

Gas gangreneGas gangrene

Toxin mediated breakdown of muscle tissueToxin mediated breakdown of muscle tissue

Rapid progression { Uterus }Rapid progression { Uterus }

Liquefactive necrosis of muscle , gas formation , Liquefactive necrosis of muscle , gas formation , toxemiatoxemia

Fulminant septicemiaFulminant septicemia

Intravascular hemolysisIntravascular hemolysis

HemoglobinuriaHemoglobinuria

Blood cultures positive in 15 % of patientsBlood cultures positive in 15 % of patients

PATHOGENESISPATHOGENESIS

5 – Toxins [ A – E ]5 – Toxins [ A – E ]

Phospholipase C { alpha toxin }Phospholipase C { alpha toxin }Acts on membranes of muscle cells , leukocytes and Acts on membranes of muscle cells , leukocytes and platelets .platelets .

Play major role in the pathogenesis of C. myonecrosisPlay major role in the pathogenesis of C. myonecrosis

Has necrotizing activity Has necrotizing activity

Other toxins :- collagenase , proteinase , Other toxins :- collagenase , proteinase , DNAs DNAs

Clinical pictureClinical picture

Acute progressive pain , edema , skin Acute progressive pain , edema , skin discolorationdiscoloration

Systemic – fever , tachycardia , hypotension , Systemic – fever , tachycardia , hypotension , renal failure , crepitus , pulmonary edema , renal failure , crepitus , pulmonary edema , deathdeath

ETIOLOGYETIOLOGY

C.perfringens { 80% }C.perfringens { 80% }

C.NovyiC.Novyi

C.SepticumC.Septicum

C.HistolyticumC.Histolyticum

DIAGNOSISDIAGNOSIS

CLINICALCLINICALSURGICALSURGICALMICRO.MICRO.– Gram stain :- G PB , absent leukocytesGram stain :- G PB , absent leukocytes– Culture { aerobic and anaerobic }Culture { aerobic and anaerobic }

Exudate , aspiratesExudate , aspiratesTissueTissueBloodBlood

– Nagler reactionNagler reaction

FOOD POISONINGFOOD POISONING

One of most common bacterial causes of food –borne One of most common bacterial causes of food –borne illnessillnessSporadic cases and outbreaks Sporadic cases and outbreaks Almost all due to type A Almost all due to type A Improperly cooked meat or meat productImproperly cooked meat or meat productIngestion of vegetative cells [ 10Ingestion of vegetative cells [ 108 ]8 ]

Afebrile Crampy abdominal pain - diarrhea within 7-Afebrile Crampy abdominal pain - diarrhea within 7-15 h 15 h Enterotoxin [ SPORULATION ]Enterotoxin [ SPORULATION ]Mild illness , recovery after 2-3 days Mild illness , recovery after 2-3 days

TRATMENTTRATMENT

Early and complete surgical excision of Early and complete surgical excision of necrotic infected tissue { most important }necrotic infected tissue { most important }

High dose of :-High dose of :-Penicillin G IVPenicillin G IV

MetronidazoleMetronidazole

ClindamycinClindamycin

Management of shock , hemolysis , anemiaManagement of shock , hemolysis , anemia

C . DifficileC . Difficile

Pseudomembranous colitisPseudomembranous colitisAntimicrobial associated diarrheaAntimicrobial associated diarrhea

Hospital acquired diarrheaHospital acquired diarrhea

EpidemiologyEpidemiology

Clostridium difficileClostridium difficile causes causes antibiotic antibiotic associated diarrhea (AD) associated diarrhea (AD) and more and more serious intestinal conditions such as serious intestinal conditions such as colitiscolitis and and pseudo membranous pseudo membranous colitiscolitis .  . 

Overgrowth of Overgrowth of Clostridium difficileClostridium difficile in the in the colon, usually after the normal flora has colon, usually after the normal flora has been disturbed by anti microbial been disturbed by anti microbial chemotherapychemotherapy

EPIDEMIOLOGYEPIDEMIOLOGY

SoilSoil

Human and animal fecesHuman and animal feces

Hospital environment {Reservoirs}Hospital environment {Reservoirs}

Spores acquired –Spores acquired –EnvironmentEnvironment

Fecal – oral { colonized persons }Fecal – oral { colonized persons }

Intestinal colonization rateIntestinal colonization rateHealthy neonates , young infant [ 50 %]Healthy neonates , young infant [ 50 %]

Children > 2yrs , adults {3 % }Children > 2yrs , adults {3 % }

CLINICAL PICTURECLINICAL PICTURE

Mild diarrhea , asymptomatic carriage – Toxic Mild diarrhea , asymptomatic carriage – Toxic megacolon ,bowel perforation and deathmegacolon ,bowel perforation and deathPseudomembranous colitisPseudomembranous colitis

Bloody diarrhea , abdominal cramps,Bloody diarrhea , abdominal cramps,Fever , systemic toxicityFever , systemic toxicityColonic mucosa – yellowish plaquesColonic mucosa – yellowish plaques

Sever disease – neutropenic , inflammatory Sever disease – neutropenic , inflammatory bowel disease .bowel disease .

Control MeasuresControl Measures

Proper hand washing {contact precautions}Proper hand washing {contact precautions}

Limiting use of antimicrobial agentsLimiting use of antimicrobial agents

Isolation of patients with diarrhea Isolation of patients with diarrhea

Disinfection of pt. roomsDisinfection of pt. rooms

TREATMENTTREATMENT

Discontinue antimicrobial therapy { clinical Discontinue antimicrobial therapy { clinical significant diarrhea or colitissignificant diarrhea or colitis

Antimicrobial therapy : severe toxicity , Antimicrobial therapy : severe toxicity , persistent diarrheapersistent diarrhea

Metronidazole for 7-10 days , oral , IV Metronidazole for 7-10 days , oral , IV

Oral vancomycin : {emergence of VRE }Oral vancomycin : {emergence of VRE }

10-20 % relapse rate10-20 % relapse rate

Antimotility drugs : contraindicated Antimotility drugs : contraindicated

Risk FactorsRisk Factors

Exposure to organismsExposure to organismsDisturbed normal gut flora {proliferate – toxin}Disturbed normal gut flora {proliferate – toxin}

Repeated enema Repeated enema Prolonged NG tubeProlonged NG tubeGI surgery GI surgery Bowel stasisBowel stasisAntimicrobials : penicillins , clindamycin , Antimicrobials : penicillins , clindamycin , Cephalosporins Cephalosporins

PATHOGENESISPATHOGENESIS

TOXINSTOXINSTOXIN A [ Enterotoxin ]TOXIN A [ Enterotoxin ]

TOXIN B [ Cytotoxin ] , more potent TOXIN B [ Cytotoxin ] , more potent

Most strains produce both or no toxinsMost strains produce both or no toxins

DIAGNOSISDIAGNOSIS

Endoscopy : pseudomembranes and Endoscopy : pseudomembranes and Hyperemic rectal mucosaHyperemic rectal mucosa

Stool : toxins { EIA } , Cell culture Stool : toxins { EIA } , Cell culture Confirm toxigenic strainsConfirm toxigenic strains

Isolation of C. Difficile { not diagnostic }Isolation of C. Difficile { not diagnostic }

PCR PCR

C.BOTULINUMC.BOTULINUM

BOTULISMBOTULISM

TRANSMISSIONTRANSMISSION

SPORESSPORES

VEGETABLES , MEATS ,FISHVEGETABLES , MEATS ,FISH

CANNED FOODCANNED FOOD

PREFORMED TOXINPREFORMED TOXIN

PATHOGENESISPATHOGENESISTOXIN (PHAGE)TOXIN (PHAGE)

MOST TOXIC SUBSTANCEMOST TOXIC SUBSTANCE

GUT BLOOD GUT BLOOD PERIPHERAL NERVE SYNAPSESPERIPHERAL NERVE SYNAPSES

BLOKS RELEASE OF ACETYLCHLINEBLOKS RELEASE OF ACETYLCHLINE

FLACCID PARALYSIS FLACCID PARALYSIS

CLINICALCLINICAL

DESCENDING PARALYSISDESCENDING PARALYSIS– DIPLOPIADIPLOPIA– DYSPHAGIADYSPHAGIA– RESPIRATORY MUSCLE FAILURERESPIRATORY MUSCLE FAILURE

NO FEVERNO FEVER

WOUND , INFANT BOTULISM ( honey )WOUND , INFANT BOTULISM ( honey )

DiagnosisDiagnosis : clinical : clinical (TOXIN ,FOOD SERUM )(TOXIN ,FOOD SERUM )

PREVENTIONPREVENTION– STERILIZATION OF STERILIZATION OF

CANNED FOODCANNED FOOD

TREATMENTTREATMENT– ANTITOXINANTITOXIN

– A , B ,EA , B ,E

RESPIRATORY RESPIRATORY SUPPORTSUPPORT