SURGICAL INFECTIONS & ANTIBIOTICS M K ALAM MS, FRCS Prof. & Consultant Surgeon College of Medicine & RCH

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

INFECTION Invasion of the body by pathogenic microorganisms and reaction of the host to organisms and their toxins Invasion of the body by pathogenic microorganisms and reaction of the host to organisms and their toxins

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

Surgical Infection A major challenge A major challenge Accounts for 1/3 of surgical patients Accounts for 1/3 of surgical patients Morbidity Morbidity Mortality Mortality Increased cost to healthcare Increased cost to healthcare

Factors contributing to infections Microorganism related factors: Microorganism related factors: -Adequate dose -Adequate dose -Virulence of microorganisms -Virulence of microorganisms Host related factors: Host related factors: -Suitable environment ( closed space ) -Suitable environment ( closed space ) -Susceptible host -Susceptible host

Pathogenicity of bacteria Exotoxins: specific, soluble proteins, remote cytotoxic effect Cl.Tetani, Strep. pyogenes Cl.Tetani, Strep. pyogenes Endotoxins: part of gram-negative bacterial wall, lipopolysaccharides e.g., E coli Resist phagocytosis: Protective capsule Klebsiela and Strep. pneumoniae Klebsiela and Strep. pneumoniae

Host Resistance  Intact skin / mucous membrane. (surgery/ trauma- causes breach) (surgery/ trauma- causes breach)  Immunity: Cellular (phagocytes ) Cellular (phagocytes ) Antibodies Antibodies

Clinical features Clinical features Local- pain, heat, redness, swelling, Local- pain, heat, redness, swelling, loss of function. loss of function. (apparent in superficial infections) (apparent in superficial infections) Systemic- fever, tachycardia, chills Systemic- fever, tachycardia, chills

Principles of surgical treatment Principles of surgical treatment Debridement- necrotic, injured tissue Debridement- necrotic, injured tissue Drainage- abscess, infected fluid Drainage- abscess, infected fluid Removal- infection source, foreign body Removal- infection source, foreign body Supportive measures: Supportive measures: immobilization immobilization elevation elevation antibiotics antibiotics

STREPTOCOCCI Gram positive, aerobe/anaerobe Gram positive, aerobe/anaerobe Flora of the mouth and pharynx, ( bowel ) Flora of the mouth and pharynx, ( bowel ) Streptococcus pyogenes –( β hemolytic) 90% of infections e.g.,lymphangitis, cellulitis, rheumatic fever Streptococcus pyogenes –( β hemolytic) 90% of infections e.g.,lymphangitis, cellulitis, rheumatic fever Strep. viridens- endocarditis, urinary infection Strep. viridens- endocarditis, urinary infection Strep. fecalis – urinary infection, pyogenic infection Strep. fecalis – urinary infection, pyogenic infection Strep. pneumonae – pneumonia, meningitis Strep. pneumonae – pneumonia, meningitis

STAPHYLOCOCCI Inhabitants of skin, Gram positive Inhabitants of skin, Gram positive Infection characterized by suppuration Infection 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 )

CLOSTRIDIA Gram positive, anaerobe Gram positive, anaerobe Rod shaped microorganisms Rod shaped microorganisms Live in bowel & soil Live in bowel & soil Produce exotoxin for pathogenicity Produce 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 )

GRAM NEGATIVE ORGANISMS ( Enterobactericiae ) Escherichia coli Escherichia coli Facultative anaerobe, Intestinal flora Produce exotoxin & endotoxin Endotoxin produce Gram-negative shock Wound infection, abdominal abscess, UTI, meningitis, endocarditis Treatment- ampicillin, cephalosporin, aminoglycoside

GRAM NEGATIVE ORGANISMS Pseudomonas Pseudomonas aerobes, occurs on skin surface aerobes, occurs on skin surface opportunistic pathogen opportunistic pathogen may cause serious & lethal infection may cause serious & lethal infection colonize ventilators, iv catheters, urinary catheters colonize ventilators, iv catheters, urinary catheters Wound infection, burn, septicemia Wound infection, burn, septicemia Treatment: aminoglycosides, piperacillin, ceftazidime Treatment: aminoglycosides, piperacillin, ceftazidime

GRAM NEGATVE ANAEROBES Bacteroides fragilis Normal flora in oral cavity, colon Normal flora in oral cavity, colon Intra-abdominal & gynecologic infections ( 90% ) Intra-abdominal & gynecologic infections ( 90% ) Foul smelling pus, gas in surrounding tissue, necrosis Foul smelling pus, gas in surrounding tissue, necrosis Spiking fever, jaundice, Leukocytosis Spiking fever, jaundice, Leukocytosis No growth on standard culture No growth on standard culture Needs anaerobe culture media Needs anaerobe culture media Treatment: Treatment: Surgical drainage Antibiotics- clindamycin, metronidazole

TYPES OF SURGICAL INFECTION A. Surgical Site Infection A. Surgical Site Infection B. Soft Tissue Infection B. Soft Tissue Infection C. Body Cavity Infection C. Body Cavity Infection D. Prosthetic Device related Infection D. Prosthetic Device related Infection E. Miscellaneous E. Miscellaneous

Surgical site infection (SSI) 38% of all surgical infections 38% of all surgical infections Infection within 30 days of operation Infection within 30 days of operation Classification: Classification: Superficial: Superficial SSI–infection in subcutaneous plane (47%) Superficial: Superficial SSI–infection in subcutaneous plane (47%) Deep: Subfascial SSI- muscle plane (23%) Deep: Subfascial SSI- muscle plane (23%) Organ/ space SSI- intra-abdominal, other spaces (30%) Organ/ space SSI- intra-abdominal, other spaces (30%) Staph. aureus- most common organism Staph. aureus- most common organism E coli, Entercoccus,other Entetobacteriaceae- deep infections E coli, Entercoccus,other Entetobacteriaceae- deep infections B fragilis – intrabd. abscess B fragilis – intrabd. abscess

Surgical site infection (SSI) Risk factors: age, malnutrition, obesity, immunocompromised, poor surg. tech, prolonged surgery, preop. shaving and type of surgery. Risk factors: age, malnutrition, obesity, immunocompromised, poor surg. tech, prolonged surgery, preop. shaving and type of surgery. Diagnosis: Diagnosis: Sup.SSI- erythema, oedema, discharge and pain Sup.SSI- erythema, oedema, discharge and pain Deep infections- no local signs, fever, pain, hypotension. need investigations. Deep infections- no local signs, fever, pain, hypotension. need investigations. Treatment: surgical / radiological intervention. Treatment: surgical / radiological intervention.

Prevention of SSI Pre-op: Treat pre-existing infection Pre-op: Treat pre-existing infection Improve general nutrition Improve general nutrition Shorter hospital stay Shorter hospital stay Pre-op. shower Pre-op. shower Hair removal timing? Hair removal timing? Intraoperative: Antiseptic technique Intraoperative: Antiseptic technique Surgical technique Surgical technique Post-operative: Hand hygiene Post-operative: Hand hygiene

STREPTOCOCCAL INFECTIONS Erysipelas Superficial spreading cellulitis & lymphangitis Superficial spreading cellulitis & lymphangitis Area of redness, sharply defined irregular border Area of redness, sharply defined irregular border Follows minor skin injuries Follows minor skin injuries Strep pyogenes Strep pyogenes Common site: around nose extending to both cheeks Common site: around nose extending to both cheeks Penicillin, Erythromycin Penicillin, Erythromycin

SREPTOCOCCAL INFECTION Cellulitis Inflammation of skin & subcutaneous tissue Inflammation of skin & subcutaneous tissue Non-suppurative Non-suppurative Strep. Pyogenes Strep. Pyogenes Common sites- limbs Common sites- limbs Affected area is red, hot & indurated Affected area is red, hot & indurated Treatment : Rest, elevation of affected limb Treatment : Rest, elevation of affected limb Penicillin, Erythromycin Penicillin, Erythromycin Fluocloxacillin ( staph. suspected ) Fluocloxacillin ( staph. suspected )

NECROTIZING FASCIITIS Necrosis of superficial fascia, overlying skin Necrosis of superficial fascia, overlying skin Polymicrobial : Streptococci (90%), Polymicrobial : Streptococci (90%), anaerobic Grampositive Cocci, aerobic Gram-negative Bacilli, and the Bacteroides spp. anaerobic Grampositive Cocci, aerobic Gram-negative Bacilli, and the Bacteroides spp. Sites- abd.wall (Meleny’s), Sites- abd.wall (Meleny’s), perineum (Fournier’s), perineum (Fournier’s), limbs, limbs, Usually follows abdominal surgery or trauma Usually follows abdominal surgery or trauma

NECROTIZING FASCIITIS Diabetics more susceptible Diabetics more susceptible Starts as cellulitis, edema, systemic toxicity Starts as cellulitis, edema, systemic toxicity Appears less extensive than actual necrosis Appears less extensive than actual necrosis Investigation: Aspiration, Gram’s stain, CT, MRI Investigation: Aspiration, Gram’s stain, CT, MRI Treatment: IV fluid, IV antibiotics Treatment: IV fluid, IV antibiotics (ampicillin, clindamycin l metronidazole, aminoglycosides ) (ampicillin, clindamycin l metronidazole, aminoglycosides ) Debridement, repeated dressings, skin grafting Debridement, repeated dressings, skin grafting

STAPHYLCOCCAL INFECTIONS STAPHYLCOCCAL INFECTIONS Abscess- localized pus collection Treatment- drainage, antibiotics Abscess- localized pus collection Treatment- drainage, antibiotics Furuncle- infection of hair follicle / sweat glands Furuncle- infection of hair follicle / sweat glands Carbuncle- extension of furuncle into subcut. tissue Carbuncle- extension of furuncle into subcut. tissue common in diabetics common in diabetics common sites- back, back of neck common sites- back, back of neck Treatment: drainage, antibiotics, control diabetes Treatment: drainage, antibiotics, control diabetes

GAS GANGRENE Cl. Perfringens, Cl. Septicum Cl. Perfringens, Cl. Septicum Exotoxins: lecithinase, collagenase, hyaluridase Exotoxins: lecithinase, collagenase, hyaluridase Large wounds of muscle ( contaminated by soil, foreign body ) Large wounds of muscle ( contaminated by soil, foreign body ) Rapid myonecrosis, crepitus in subcutaneous tissue Rapid myonecrosis, crepitus in subcutaneous tissue Seropurulent discharge, foul smell, swollen Seropurulent discharge, foul smell, swollen Toxemia, tachycardia, ill looking Toxemia, tachycardia, ill looking X-ray: gas in muscle and under skin X-ray: gas in muscle and under skin Penicillin, clindamycin, metronidazole Penicillin, clindamycin, metronidazole Wound exposure, debridement, drainage, amputation Wound exposure, debridement, drainage, amputation Hyperbaric oxygen Hyperbaric oxygen

TETANUS Cl. Tetani, produce neurotoxin Cl. Tetani, produce neurotoxin Penetrating wound ( rusty nail, thorn ) Penetrating wound ( rusty nail, thorn ) Usually wound healed when symptoms appear Usually wound healed when symptoms appear Incubation period: 7-10 days Incubation period: 7-10 days Trismus- first symptom, stiffness in neck & back Trismus- first symptom, stiffness in neck & back Anxious look with mouth drawn up ( risus sardonicus) Anxious look with mouth drawn up ( risus sardonicus) Respiration & swallowing progressively difficult Respiration & swallowing progressively difficult Reflex convulsions along with tonic spasm Reflex convulsions along with tonic spasm Death by exhaustion, aspiration or asphyxiation Death by exhaustion, aspiration or asphyxiation

TETANUS Treatment: Treatment: wound debridement, penicillin wound debridement, penicillin Muscle relaxants, ventilatory support Muscle relaxants, ventilatory support Nutritional support Nutritional support Prophylaxis: Prophylaxis: wound care, antibiotics wound care, antibiotics Human TIG in high risk ( un-immunized ) Human TIG in high risk ( un-immunized ) Commence active immunization ( T toxoid) Previously immunized - booster >10 years needs a booster dose Commence active immunization ( T toxoid) Previously immunized - booster >10 years needs a booster dose booster <10 years- no treatment in low risk wounds booster <10 years- no treatment in low risk wounds

PSEUDOMEMBRANOUS COLITIS Cl. Difficile Cl. Difficile Overtakes normal flora in patients on antibiotics Overtakes normal flora in patients on antibiotics Watery diarrhea, abdominal pain, fever Watery diarrhea, abdominal pain, fever Sigmoidoscopy: membrane of exudates (pseudomembranes) Sigmoidoscopy: membrane of exudates (pseudomembranes) Stool- culture and toxin assay Stool- culture and toxin assay Treatment : Treatment : stop offending antibiotic stop offending antibiotic oral vancomycin/ metronidazole oral vancomycin/ metronidazole rehydration, isolate patient rehydration, isolate patient

Body Cavity Infection Primary peritonitis: Primary peritonitis: Spontaneous Spontaneous Children, Ascitic Children, Ascitic Haematogenous/ lymphatic route Haematogenous/ lymphatic route Antibiotic Antibiotic Secondary peritonitis: Secondary peritonitis: Inflam./ rupture of viscera Inflam./ rupture of viscera Polymicrobial Polymicrobial Investigations: blood, radiological Investigations: blood, radiological Treatment of original cause Treatment of original cause

Prosthetic Device Related Infection Artificial valves and joints Artificial valves and joints Peritoneal and haemodialysis catheters Peritoneal and haemodialysis catheters Vascular grafts Vascular grafts Staphylococcus aureus Staphylococcus aureus Antibiotics, washing of prosthesis or removal Antibiotics, washing of prosthesis or removal

Hospital Acquired Infection Occurring within 48 h of hospital admission, three days of discharge or 30 days following an operation Occurring within 48 h of hospital admission, three days of discharge or 30 days following an operation 10% of patients admitted to hospitals 10% of patients admitted to hospitals Spent 2.5-times longer in hospital - UK Spent 2.5-times longer in hospital - UK Highest prevalence in ICU- Highest prevalence in ICU- Enterococcus, Pseudomonas spp.,E coli, Staph. aureus. Enterococcus, Pseudomonas spp.,E coli, Staph. aureus. Sites: Urinary, surg. Wounds, resp., skin, blood, GIT Sites: Urinary, surg. Wounds, resp., skin, blood, GIT

ANTIBIOTICS Chemotherapeutic agents that act on organisms Chemotherapeutic agents that act on organisms Bacteriocidal: Penicillin, Cephalosporin, Vancomycin Bacteriocidal: Penicillin, Cephalosporin, Vancomycin Aminoglycosides Aminoglycosides Bacteriostatic: Erythromycin, Clindamycin, Tetracycline Bacteriostatic: Erythromycin, Clindamycin, Tetracycline

ANTIBIOTICS Penicillins- Penicillin G, Piperacillin Penicillins- Penicillin G, Piperacillin Penicillins with β-lactamase inhibitors- Tazocin Penicillins with β-lactamase inhibitors- Tazocin Cephalosporins (I, II, III)- Cephalexin, Cefuroxime, Ceftriaxone Cephalosporins (I, II, III)- Cephalexin, Cefuroxime, Ceftriaxone Carbapenems- Imipenem, Meropenem Carbapenems- Imipenem, Meropenem Aminoglycosides- Gentamycin, Amikacin Aminoglycosides- Gentamycin, Amikacin Fluoroquinolones- Ciprofloxacin Fluoroquinolones- Ciprofloxacin Glycopeptides- Vancomycin Glycopeptides- Vancomycin Macrolides- Erythromycin, Clarithromycin Macrolides- Erythromycin, Clarithromycin Tetracyclines- Minocycline, Doxycycline Tetracyclines- Minocycline, Doxycycline

ROLE OF ANTIBIOTICS Therapeutic: To treat existing infection Therapeutic: To treat existing infection Prophylactic: To reduce the risk of wound infection Prophylactic: To reduce the risk of wound infection

ANTIBIOTIC THERAPY Pseudomembranous colitis- oral vancomycin/ metronidazole Pseudomembranous colitis- oral vancomycin/ metronidazole Biliary-tract infection- cephalosporin or gentamycin Biliary-tract infection- cephalosporin or gentamycin Peritonitis- cephalosporin/ gentamycin + metronidazole/ clindamycin Peritonitis- cephalosporin/ gentamycin + metronidazole/ clindamycin Septicemia- aminoglycoside + ceftazidime, Tazocin or imipenem, ( may add metronidazole ) Septicemia- aminoglycoside + ceftazidime, Tazocin or imipenem, ( may add metronidazole ) Septicemia due to vascular catheter- Flucloxacillin/ vancomycin or Cefuroxime Septicemia due to vascular catheter- Flucloxacillin/ vancomycin or Cefuroxime Cellulitis- penicillin, erythromycin ( flucloxacillin if Staphylococcus infection. Suspected ) Cellulitis- penicillin, erythromycin ( flucloxacillin if Staphylococcus infection. Suspected )

ANTIBIOTIC PROPHYLAXIS BASED ON SURGICAL WOUND CLASSIFICATION Clean wound - e.g., thyroid surgery ( 2% ) Clean wound - e.g., thyroid surgery ( 2% ) Clean-contaminated - minimal contamination e.g., biliary, urinary, GI tract surgery ( 5-10% ) Clean-contaminated - minimal contamination e.g., biliary, urinary, GI tract surgery ( 5-10% ) Contaminated -gross contamination e.g., during bowel surgery- (up to 20% ) Contaminated -gross contamination e.g., during bowel surgery- (up to 20% ) Dirty- surgery through established infection e.g., peritonitis ( up to 50% ) Dirty- surgery through established infection e.g., peritonitis ( up to 50% )

ANTIBIOTIC PROPHYLAXIS Prophylaxis in clean-contaminated/ high risk clean wounds Prophylaxis in clean-contaminated/ high risk clean wounds Antibiotic is given just before patient sent for surgery Antibiotic is given just before patient sent for surgery Duration of antibiotic is controversial ( one dose- 24 hour regimen ) Duration of antibiotic is controversial ( one dose- 24 hour regimen )