SURGICAL INFECTIONSSURGICAL INFECTIONS&&

ANTIBIOTICSANTIBIOTICS

OBJECTIVESOBJECTIVES

Definitions.Definitions. Pathogenesis .Pathogenesis . Clinical features .Clinical features . Surgical microbiology.Surgical microbiology. Common infections.Common infections. Antibiotics use.Antibiotics use.

SURGICAL INFECTIONSSURGICAL INFECTIONS

Infections that require surgical Infections that require surgical intervention as a treatment or develop intervention as a treatment or develop as a result of surgical procedure.as a result of surgical procedure.

Surgical InfectionSurgical Infection

A major challengeA major challenge

Accounts for 1/3 of surgical patientsAccounts for 1/3 of surgical patients

Increased cost to healthcare Increased cost to healthcare

PHYSIOLOGYPHYSIOLOGY Micro-organisms are normally Micro-organisms are normally

prevented from causing infection in prevented from causing infection in tissues by intact epithelial surfaces. tissues by intact epithelial surfaces. These are broken down in trauma and These are broken down in trauma and by surgery. by surgery.

there are other protective mechanisms, there are other protective mechanisms, which can be dividedwhich can be dividedinto:into:• • chemical: low gastric pH;chemical: low gastric pH;• • humoral: antibodies, complement and humoral: antibodies, complement and opsonins;opsonins;• • cellular: phagocytic cells, macrophages, cellular: phagocytic cells, macrophages, polymorphonuclear polymorphonuclear cells and killer cells and killer lymphocytes.lymphocytes.

causescauses of reduced host resistance of reduced host resistance to infectionto infection■ ■ Metabolic: malnutrition Metabolic: malnutrition (including obesity), diabetes,(including obesity), diabetes,uraemia, jaundiceuraemia, jaundice■ ■ Disseminated disease: cancer Disseminated disease: cancer and acquired immunodeficiency and acquired immunodeficiency syndrome (AIDS)syndrome (AIDS)■ ■ Iatrogenic: radiotherapy, Iatrogenic: radiotherapy, chemotherapy, steroidschemotherapy, steroids

Delayed healing relating to Delayed healing relating to infection in a patient on highdose infection in a patient on highdose steroid .steroid .

Pathogenicity of bacteriaPathogenicity of bacteria

Exotoxins:Exotoxins: specific, soluble proteins, remote cytotoxic effectspecific, soluble proteins, remote cytotoxic effect

Cl.Tetani, Strep. pyogenesCl.Tetani, Strep. pyogenes

Endotoxins:Endotoxins: part of gram-negative bacterial wall, part of gram-negative bacterial wall, lipopolysaccharides e.g., E coli lipopolysaccharides e.g., E coli

Resist phagocytosisResist phagocytosis:: Protective capsule Protective capsule

Klebsiela and Strep. pneumoniaeKlebsiela and Strep. pneumoniae

Preventation of surgical Preventation of surgical infectionsinfections

**Pt in best general condition (host **Pt in best general condition (host defense).defense).

**minimize introduction of pathogenesis **minimize introduction of pathogenesis during surgery .during surgery .

**good surgical technique .**good surgical technique .

**peri-operative care (support defence) .**peri-operative care (support defence) .

Clinical features Clinical features

LocalLocal

pain, heat, redness, swelling, pain, heat, redness, swelling,

loss of function.loss of function. (apparent in superficial infections)(apparent in superficial infections)

SystemicSystemic

tachycardia, pyrexia and a raised white counttachycardia, pyrexia and a raised white count

[systemic inflammatory response syndrome [systemic inflammatory response syndrome (SIRS)](SIRS)]

InvestigationInvestigation

*** Leukocytosis .*** Leukocytosis .

***Exudate (gram stain , culture)***Exudate (gram stain , culture)

***Blood culture .***Blood culture .

***Special Inv. (radiology , biobsy)***Special Inv. (radiology , biobsy)

Principles of surgical Principles of surgical treatment treatment

DebridementDebridement necrotic, injured tissuenecrotic, injured tissue DrainageDrainage abscess, infected fluidabscess, infected fluid RemovalRemoval infection source, foreign bodyinfection source, foreign body Supportive measures:Supportive measures:

• immobilizationimmobilization• elevationelevation• antibioticsantibiotics

Common infectionsCommon infections

STREPTOCOCCISTREPTOCOCCI Gram positive, aerobe/anaerobeGram positive, aerobe/anaerobe

Flora of the mouth and pharynx, ( bowel )Flora of the mouth and pharynx, ( bowel )

Streptococcus pyogenes Streptococcus pyogenes –( –( β hemolytic)β hemolytic) 90% of 90% of infections e.g.,lymphangitis, cellulitis, rheumatic infections e.g.,lymphangitis, cellulitis, rheumatic feverfever

Strep. viridens-Strep. viridens- endocarditis, urinary infectionendocarditis, urinary infection

Strep. fecalis – Strep. fecalis – urinary infection, pyogenic urinary infection, pyogenic infectioninfection

Strep. pneumonae – Strep. pneumonae – pneumonia, meningitispneumonia, meningitis

STREPTOCOCCAL STREPTOCOCCAL INFECTIONSINFECTIONS

ErysipelasErysipelas Superficial spreading cellulitis & lymphangitisSuperficial spreading cellulitis & lymphangitis Area of redness, sharply defined irregular Area of redness, sharply defined irregular

borderborder Follows minor skin injuriesFollows minor skin injuries Strep pyogenesStrep pyogenes Common site: around nose extending to both Common site: around nose extending to both

cheekscheeks Treatment: Treatment: Penicillin, ErythromycinPenicillin, Erythromycin

SREPTOCOCCAL INFECTIONSREPTOCOCCAL INFECTION

CellulitisCellulitis

Inflammation of skin & subcutaneous tissueInflammation of skin & subcutaneous tissue Non-suppurativeNon-suppurative Strep. PyogenesStrep. Pyogenes Common sites- limbsCommon sites- limbs Affected area is red, hot & induratedAffected area is red, hot & indurated Treatment :Treatment : Rest, elevation of affected limb Rest, elevation of affected limb Penicillin, ErythromycinPenicillin, Erythromycin Fluocloxacillin ( staph. suspected )Fluocloxacillin ( staph. suspected )

Streptococcal cellulitis of Streptococcal cellulitis of the legthe leg

NECROTIZING FASCIITISNECROTIZING FASCIITIS

Necrosis of superficial fascia, overlying skinNecrosis of superficial fascia, overlying skin

Polymicrobial : Polymicrobial : Streptococci (90%), Streptococci (90%),

anaerobic Grampositive Cocci, aerobic Gram-negative anaerobic Grampositive Cocci, aerobic Gram-negative Bacilli, and the Bacteroides spp.Bacilli, and the Bacteroides spp.

Sites- Sites- abd.wall abd.wall (Meleny’s)(Meleny’s), ,

perineumperineum (Fournier’s)(Fournier’s), ,

limbs,limbs,

Usually follows abdominal surgery or traumaUsually follows abdominal surgery or trauma

NECROTIZING FASCIITISNECROTIZING FASCIITIS

Diabetics more susceptibleDiabetics more susceptible

Starts as cellulitis, edema, systemic toxicityStarts as cellulitis, edema, systemic toxicity

Appears less extensive than actual necrosisAppears less extensive than actual necrosis Investigation: Aspiration, Gram’s stain, CT, MRIInvestigation: Aspiration, Gram’s stain, CT, MRI

Treatment: IV fluid, IV antibioticsTreatment: IV fluid, IV antibiotics (ampicillin, clindamycin l metronidazole, aminoglycosides )(ampicillin, clindamycin l metronidazole, aminoglycosides )

Debridement , repeated dressings, skin grafting Debridement , repeated dressings, skin grafting

STAPHYLOCOCCISTAPHYLOCOCCI

Inhabitants of skin, Gram positiveInhabitants of skin, Gram positive

Infection characterized by suppurationInfection characterized by suppuration

Staph.aureus- Staph.aureus-

SSI, nosocomial ,superficial infections SSI, nosocomial ,superficial infections

Staph. epidermidis- Staph. epidermidis-

opportunistic ( wound, endocarditis )opportunistic ( wound, endocarditis )

STAPHYLCOCCAL STAPHYLCOCCAL INFECTIONSINFECTIONS

Abscess-Abscess- localized pus collection localized pus collection Treatment- drainage, Treatment- drainage,

antibioticsantibiotics

Furuncle- Furuncle- infection of hair follicle / sweat glandsinfection of hair follicle / sweat glands

Carbuncle- Carbuncle- extension of furuncle into subcut. tissueextension of furuncle into subcut. tissue

common in diabeticscommon in diabetics

common sites- back, back of neckcommon sites- back, back of neck

Treatment: drainage, antibiotics, control diabetesTreatment: drainage, antibiotics, control diabetes

Surgical site infection Surgical site infection (SSI)(SSI)

38% of all surgical infections38% of all surgical infections Infection within 30 days of operationInfection within 30 days of operation Classification:Classification: Superficial:Superficial: Superficial SSI–infection in subcutaneous Superficial SSI–infection in subcutaneous

plane (47%)plane (47%) Deep:Deep: Subfascial SSI-Subfascial SSI- muscle plane (23%)muscle plane (23%)

Organ/ space SSI-Organ/ space SSI- intra-abdominal, other spaces intra-abdominal, other spaces (30%)(30%)

Staph. aureusStaph. aureus most common organism most common organism E coliE coli, Entercoccus ,other Entetobacteriaceae- deep , Entercoccus ,other Entetobacteriaceae- deep

infectionsinfections B fragilis – intrabd. abscessB fragilis – intrabd. abscess

Surgical site infection Surgical site infection (SSI)(SSI)

Risk factors: Risk factors: age, malnutrition, age, malnutrition, obesity, immunocompromised, poor obesity, immunocompromised, poor surg. tech, prolonged surgery, preop. surg. tech, prolonged surgery, preop. shaving and type of surgery.shaving and type of surgery.

Diagnosis: Diagnosis: Superficial infection Superficial infection erythema, oedema, erythema, oedema,

discharge and pain discharge and pain Deep infections- Deep infections- no local signs, fever, pain, no local signs, fever, pain,

hypotension. need investigations.hypotension. need investigations. Treatment:Treatment: surgical / radiological interventionsurgical / radiological intervention. .

Prevention of SSIPrevention of SSI

Pre-op:Pre-op: Treat pre-existing infection Treat pre-existing infection

Improve general nutritionImprove general nutrition

Shorter hospital stayShorter hospital stay

Pre-op. showerPre-op. shower

Hair removal timing?Hair removal timing? Intraoperative:Intraoperative: Antiseptic technique Antiseptic technique

good Surgical techniquegood Surgical technique Post-operative:Post-operative: Hand hygiene Hand hygiene

GRAM NEGATIVE ORGANISMSGRAM NEGATIVE ORGANISMS( Enterobactericiae )( Enterobactericiae )

Escherichia coliEscherichia coli

Facultative anaerobe, Intestinal floraFacultative anaerobe, Intestinal flora

Produce exotoxin & endotoxinProduce exotoxin & endotoxin

Endotoxin produce Gram-negative shock Endotoxin produce Gram-negative shock

Wound infection, abdominal abscess,Wound infection, abdominal abscess,

UTI, meningitis, endocarditisUTI, meningitis, endocarditis

TreatmentTreatment ampicillin, cephalosporin, ampicillin, cephalosporin, aminoglycosideaminoglycoside

GRAM NEGATIVE GRAM NEGATIVE ORGANISMSORGANISMS

PseudomonasPseudomonas

aerobes, occurs on skin surfaceaerobes, occurs on skin surface opportunistic pathogenopportunistic pathogen may cause serious & lethal infectionmay cause serious & lethal infection colonize ventilators, iv catheters, urinary colonize ventilators, iv catheters, urinary

catheterscatheters Wound infection, burn, septicemiaWound infection, burn, septicemia Treatment:Treatment: aminoglycosides, piperacillin, ceftazidime aminoglycosides, piperacillin, ceftazidime

CLOSTRIDIACLOSTRIDIA

Gram positive, anaerobeGram positive, anaerobe Rod shaped microorganismsRod shaped microorganisms Live in bowel & soilLive in bowel & soil Produce exotoxin for pathogenicityProduce exotoxin for pathogenicity Important members:Important members: Cl. Perfringens, Cl. Septicum ( gas gangrene )Cl. Perfringens, Cl. Septicum ( gas gangrene ) Cl. Tetani ( tetanus )Cl. Tetani ( tetanus ) Cl. Difficile ( pseudomembranous colitis )Cl. Difficile ( pseudomembranous colitis )

GAS GANGRENEGAS GANGRENE Cl. Perfringens, Cl. SepticumCl. Perfringens, Cl. Septicum Exotoxins: Exotoxins: lecithinase, collagenase, hyaluridaselecithinase, collagenase, hyaluridase

Large wounds of muscle Large wounds of muscle ( contaminated by soil, foreign body )( contaminated by soil, foreign body )

Rapid myonecrosis, crepitus in subcutaneous tissueRapid myonecrosis, crepitus in subcutaneous tissue Seropurulent discharge, foul smell, swollenSeropurulent discharge, foul smell, swollen Toxemia, tachycardia, ill lookingToxemia, tachycardia, ill looking X-ray: gas in muscle and under skinX-ray: gas in muscle and under skin ttt :ttt :Penicillin, clindamycin, metronidazolePenicillin, clindamycin, metronidazole Wound exposure, debridement , drainage, Wound exposure, debridement , drainage,

amputationamputation Hyperbaric oxygenHyperbaric oxygen

TETANUSTETANUS Cl. Tetani, produce neurotoxinCl. Tetani, produce neurotoxin Penetrating wound Penetrating wound ( rusty nail, thorn )( rusty nail, thorn )

Usually wound healed when symptoms appearUsually wound healed when symptoms appear Incubation period: 7-10 daysIncubation period: 7-10 days Trismus- first symptom, stiffness in neck & backTrismus- first symptom, stiffness in neck & back Anxious look with mouth drawn up Anxious look with mouth drawn up ( risus sardonicus)( risus sardonicus)

Respiration & swallowing progressively difficultRespiration & swallowing progressively difficult Reflex convulsions along with tonic spasm Reflex convulsions along with tonic spasm Death by exhaustion, aspiration or asphyxiationDeath by exhaustion, aspiration or asphyxiation

TETANUSTETANUS

Treatment:Treatment: wound debridement, penicillinwound debridement, penicillin Muscle relaxants, ventilatory supportMuscle relaxants, ventilatory support Nutritional support Nutritional support

Prophylaxis:Prophylaxis:

wound care, antibioticswound care, antibiotics Human TIG in high risk ( un-immunized )Human TIG in high risk ( un-immunized )

Commence active immunization ( T toxoid) Commence active immunization ( T toxoid) Previously immunized Previously immunized-- booster >10 years needs a booster booster >10 years needs a booster dosedose

booster <10 years- no treatment in low risk booster <10 years- no treatment in low risk woundswounds

PSEUDOMEMBRANOUS COLITISPSEUDOMEMBRANOUS COLITIS

Cl. DifficileCl. Difficile Overtakes normal flora in patients on antibioticsOvertakes normal flora in patients on antibiotics Watery diarrhea, abdominal pain, feverWatery diarrhea, abdominal pain, fever Sigmoidoscopy: Sigmoidoscopy: membrane of exudates membrane of exudates

(pseudomembranes)(pseudomembranes) Stool- culture and toxin assayStool- culture and toxin assay Treatment :Treatment : stop offending antibioticstop offending antibiotic

oral vancomycin/ metronidazoleoral vancomycin/ metronidazole

rehydration, isolate patient rehydration, isolate patient

ANTIBIOTICSANTIBIOTICS

Chemotherapeutic agents that act on organismsChemotherapeutic agents that act on organisms

Bacteriocidal:Bacteriocidal: Penicillin, Cephalosporin, Penicillin, Cephalosporin, VancomycinVancomycin

AminoglycosidesAminoglycosides

Bacteriostatic:Bacteriostatic: Erythromycin, Clindamycin, Erythromycin, Clindamycin, Tetracycline Tetracycline

ANTIBIOTICSANTIBIOTICS PenicillinsPenicillins- - Penicillin G, PiperacillinPenicillin G, Piperacillin

Penicillins with Penicillins with ββ-lactamase inhibitors-lactamase inhibitors- - TazocinTazocin

Cephalosporins (I, II, III)Cephalosporins (I, II, III)- - Cephalexin, Cefuroxime, Cephalexin, Cefuroxime, CeftriaxoneCeftriaxone

CarbapenemsCarbapenems- - Imipenem, MeropenemImipenem, Meropenem

AminoglycosidesAminoglycosides- - Gentamycin, AmikacinGentamycin, Amikacin

FluoroquinolonesFluoroquinolones- - CiprofloxacinCiprofloxacin

GlycopeptidesGlycopeptides- - VancomycinVancomycin

MacrolidesMacrolides- - Erythromycin, ClarithromycinErythromycin, Clarithromycin

TetracyclinesTetracyclines- - Minocycline, DoxycyclineMinocycline, Doxycycline

ROLE OF ANTIBIOTICSROLE OF ANTIBIOTICS

Therapeutic:Therapeutic: To treat existing infectionTo treat existing infection

Prophylactic:Prophylactic: To reduce the risk of wound To reduce the risk of wound infectioninfection

ANTIBIOTIC THERAPYANTIBIOTIC THERAPY

Pseudomembranous colitis-Pseudomembranous colitis- oral vancomycin/ metronidazole oral vancomycin/ metronidazole

Biliary-tract infection-Biliary-tract infection- cephalosporin or gentamycincephalosporin or gentamycin

Peritonitis-Peritonitis- cephalosporin/ gentamycin + metronidazole/ cephalosporin/ gentamycin + metronidazole/ clindamycinclindamycin

Septicemia-Septicemia- aminoglycoside + ceftazidime, Tazocin or imipenem, aminoglycoside + ceftazidime, Tazocin or imipenem, ( may add metronidazole ) ( may add metronidazole )

Septicemia due to vascular catheter-Septicemia due to vascular catheter- Flucloxacillin/ Flucloxacillin/ vancomycin vancomycin or Cefuroxime or Cefuroxime

Cellulitis-Cellulitis- penicillin, erythromycin penicillin, erythromycin ( flucloxacillin if Staphylococcus infection. Suspected ) ( flucloxacillin if Staphylococcus infection. Suspected )

ANTIBIOTIC PROPHYLAXISANTIBIOTIC PROPHYLAXIS BASED ON SURGICAL WOUND BASED ON SURGICAL WOUND

CLASSIFICATIONCLASSIFICATION

Clean wound Clean wound

Clean-contaminatedClean-contaminated

ContaminatedContaminated

DirtyDirty

Clean wound: Clean wound: class I e.g surg. Of class I e.g surg. Of thyroid gland,breast,herniathyroid gland,breast,herniano need to prophylaxis except for:no need to prophylaxis except for:**immunocomprized pt e.g. diabetecs**immunocomprized pt e.g. diabetecs**if surgery include inserting foreign **if surgery include inserting foreign materials e.g. artificial valve .materials e.g. artificial valve .**high risk pt like those with infective **high risk pt like those with infective endocarditis.endocarditis.

The risk of pos-operative wound The risk of pos-operative wound infection is 2%infection is 2%

Clean–contaminated wound:Clean–contaminated wound:

class II e.g. biliary,urinary class II e.g. biliary,urinary surg.surg.

The risk of infection is 5-The risk of infection is 5-10%10%

Contaminated wound:Contaminated wound:class III e.g. bowel surgeryclass III e.g. bowel surgery

The risk of infection is up to The risk of infection is up to 20%20%

Dirty wound :Dirty wound :class IV e.g. peritonitisclass IV e.g. peritonitisThe use of antibiotic is considered The use of antibiotic is considered to be of therapeutic nature (no to be of therapeutic nature (no prophylaxis)prophylaxis)

The risk of infection is up to 60%The risk of infection is up to 60%

Type of surgery Infection rate (%) Rate before Type of surgery Infection rate (%) Rate before prophylaxisprophylaxis

Clean 1–2 1-2%Clean 1–2 1-2%

Clean-contaminated < 10 up to 30% Clean-contaminated < 10 up to 30% Contaminated 15–20 Variable but up to Contaminated 15–20 Variable but up to 60%60%

Dirty < 40 Up to 60% or moreDirty < 40 Up to 60% or more