1、SURGICAL INFECTIONS & ANTIBIOTICS,M K ALAM MS, FRCS Prof. & Consultant Surgeon College of Medicine & RCH,OBJECTIVES,Definitions. Pathogenesis . Clinical features . Surgical microbiology. Common infections. Antibiotics use.,INFECTION,Invasion of the body by pathogenic microorganisms and reaction of t
2、he host to organisms and their toxins,SURGICAL INFECTIONS,Infections that require surgical intervention as a treatment or develop as a result of surgical procedure.,Surgical Infection,A major challengeAccounts for 1/3 of surgical patientsMorbidityMortalityIncreased cost to healthcare,Factors contrib
3、uting to infections,Microorganism related factors:-Adequate dose -Virulence of microorganismsHost related factors:-Suitable environment ( closed space )-Susceptible host,Pathogenicity of bacteria,Exotoxins: specific, soluble proteins, remote cytotoxic effectCl.Tetani, Strep. pyogenesEndotoxins: part
4、 of gram-negative bacterial wall, lipopolysaccharides e.g., E coliResist phagocytosis: Protective capsule Klebsiela and Strep. pneumoniae,Host Resistance,Intact skin / mucous membrane.(surgery/ trauma- causes breach)Immunity:Cellular (phagocytes )Antibodies,Clinical features,Local- pain, heat, redne
5、ss, swelling, loss of function.(apparent in superficial infections)Systemic- fever, tachycardia, chills,Principles of surgical treatment,Debridement- necrotic, injured tissue Drainage- abscess, infected fluid Removal- infection source, foreign body Supportive measures:immobilizationelevationantibiot
6、ics,STREPTOCOCCI,Gram positive, aerobe/anaerobeFlora of the mouth and pharynx, ( bowel )Streptococcus pyogenes ( hemolytic) 90% of infections e.g.,lymphangitis, cellulitis, rheumatic feverStrep. viridens- endocarditis, urinary infectionStrep. fecalis urinary infection, pyogenic infectionStrep. pneum
7、onae pneumonia, meningitis,STAPHYLOCOCCI,Inhabitants of skin, Gram positiveInfection characterized by suppurationStaph.aureus- SSI, nosocomial ,superficial infections Staph. epidermidis- opportunistic ( wound, endocarditis ),CLOSTRIDIA,Gram positive, anaerobe Rod shaped microorganisms Live in bowel
8、& soil Produce exotoxin for pathogenicity Important members:Cl. Perfringens, Cl. Septicum ( gas gangrene )Cl. Tetani ( tetanus )Cl. Difficile ( pseudomembranous colitis ),GRAM NEGATIVE ORGANISMS ( Enterobactericiae ),Escherichia coliFacultative anaerobe, Intestinal flora Produce exotoxin & endotoxin
9、 Endotoxin produce Gram-negative shock Wound infection, abdominal abscess, UTI, meningitis, endocarditisTreatment- ampicillin, cephalosporin, aminoglycoside,GRAM NEGATIVE ORGANISMS,Pseudomonasaerobes, occurs on skin surface opportunistic pathogen may cause serious & lethal infection colonize ventila
10、tors, iv catheters, urinary catheters Wound infection, burn, septicemia Treatment: aminoglycosides, piperacillin, ceftazidime,GRAM NEGATVE ANAEROBES Bacteroides fragilis,Normal flora in oral cavity, colon Intra-abdominal & gynecologic infections ( 90% ) Foul smelling pus, gas in surrounding tissue,
11、necrosis Spiking fever, jaundice, Leukocytosis No growth on standard culture Needs anaerobe culture media Treatment:Surgical drainageAntibiotics- clindamycin, metronidazole,TYPES OF SURGICAL INFECTION,A. Surgical Site Infection B. Soft Tissue Infection C. Body Cavity Infection D. Prosthetic Device r
12、elated Infection E. Miscellaneous,Surgical site infection (SSI),38% of all surgical infections Infection within 30 days of operation Classification:Superficial: Superficial SSIinfection in subcutaneous plane (47%)Deep: Subfascial SSI- muscle plane (23%)Organ/ space SSI- intra-abdominal, other spaces
13、 (30%) Staph. aureus- most common organism E coli, Entercoccus ,other Entetobacteriaceae- deep infectionsB fragilis intrabd. abscess,Surgical site infection (SSI),Risk factors: age, malnutrition, obesity, immunocompromised, poor surg. tech, prolonged surgery, preop. shaving and type of surgery. Diag
14、nosis: Sup.SSI- erythema, oedema, discharge and pain Deep infections- no local signs, fever, pain, hypotension. need investigations. Treatment: surgical / radiological intervention.,Prevention of SSI,Pre-op: Treat pre-existing infectionImprove general nutritionShorter hospital stayPre-op. showerHair
15、 removal timing? Intraoperative: Antiseptic techniqueSurgical technique Post-operative: Hand hygiene,STREPTOCOCCAL INFECTIONS Erysipelas,Superficial spreading cellulitis & lymphangitis Area of redness, sharply defined irregular border Follows minor skin injuries Strep pyogenes Common site: around no
16、se extending to both cheeks Penicillin, Erythromycin,SREPTOCOCCAL INFECTION Cellulitis,Inflammation of skin & subcutaneous tissue Non-suppurative Strep. Pyogenes Common sites- limbs Affected area is red, hot & indurated Treatment : Rest, elevation of affected limbPenicillin, ErythromycinFluocloxacil
17、lin ( staph. suspected ),NECROTIZING FASCIITIS,Necrosis of superficial fascia, overlying skinPolymicrobial : Streptococci (90%), anaerobic Grampositive Cocci, aerobic Gram-negative Bacilli, and the Bacteroides spp.Sites- abd.wall (Melenys), perineum (Fourniers), limbs,Usually follows abdominal surge
18、ry or trauma,NECROTIZING FASCIITIS,Diabetics more susceptibleStarts as cellulitis, edema, systemic toxicityAppears less extensive than actual necrosis Investigation: Aspiration, Grams stain, CT, MRITreatment: IV fluid, IV antibiotics(ampicillin, clindamycin l metronidazole, aminoglycosides )Debridem
19、ent , repeated dressings, skin grafting,STAPHYLCOCCAL INFECTIONS,Abscess- localized pus collection Treatment- drainage, antibioticsFuruncle- infection of hair follicle / sweat glandsCarbuncle- extension of furuncle into subcut. tissuecommon in diabeticscommon sites- back, back of neckTreatment: drai
20、nage, antibiotics, control diabetes,GAS GANGRENE,Cl. Perfringens, Cl. Septicum Exotoxins: lecithinase, collagenase, hyaluridase Large wounds of muscle ( contaminated by soil, foreign body ) Rapid myonecrosis, crepitus in subcutaneous tissue Seropurulent discharge, foul smell, swollen Toxemia, tachyc
21、ardia, ill looking X-ray: gas in muscle and under skin Penicillin, clindamycin, metronidazole Wound exposure, debridement , drainage, amputation Hyperbaric oxygen,TETANUS,Cl. Tetani, produce neurotoxin Penetrating wound ( rusty nail, thorn ) Usually wound healed when symptoms appear Incubation perio
22、d: 7-10 days Trismus- first symptom, stiffness in neck & back Anxious look with mouth drawn up ( risus sardonicus) Respiration & swallowing progressively difficult Reflex convulsions along with tonic spasm Death by exhaustion, aspiration or asphyxiation,TETANUS,Treatment:wound debridement, penicilli
23、nMuscle relaxants, ventilatory supportNutritional support Prophylaxis: wound care, antibioticsHuman TIG in high risk ( un-immunized )Commence active immunization ( T toxoid) Previously immunized- booster 10 years needs a booster dosebooster 10 years- no treatment in low risk wounds,PSEUDOMEMBRANOUS
24、COLITIS,Cl. Difficile Overtakes normal flora in patients on antibiotics Watery diarrhea, abdominal pain, fever Sigmoidoscopy: membrane of exudates (pseudomembranes) Stool- culture and toxin assay Treatment :stop offending antibioticoral vancomycin/ metronidazolerehydration, isolate patient,Body Cavi
25、ty Infection,Primary peritonitis: SpontaneousChildren, AsciticHaematogenous/ lymphatic routeAntibioticSecondary peritonitis: Inflam./ rupture of visceraPolymicrobialInvestigations: blood, radiologicalTreatment of original cause,Prosthetic Device Related Infection,Artificial valves and jointsPeritone
26、al and haemodialysis catheters Vascular graftsStaphylococcus aureusAntibiotics, 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 10% of patients admitted to hospitals Spent 2.5-times lo
27、nger in hospital - UK Highest prevalence in ICU- Enterococcus, Pseudomonas spp.,E coli, Staph. aureus. Sites: Urinary, surg. Wounds, resp., skin, blood, GIT,ANTIBIOTICS,Chemotherapeutic agents that act on organismsBacteriocidal: Penicillin, Cephalosporin, VancomycinAminoglycosidesBacteriostatic: Ery
28、thromycin, Clindamycin, Tetracycline,ANTIBIOTICS,Penicillins- Penicillin G, PiperacillinPenicillins with -lactamase inhibitors- TazocinCephalosporins (I, II, III)- Cephalexin, Cefuroxime, CeftriaxoneCarbapenems- Imipenem, MeropenemAminoglycosides- Gentamycin, AmikacinFluoroquinolones- CiprofloxacinG
29、lycopeptides- VancomycinMacrolides- Erythromycin, ClarithromycinTetracyclines- Minocycline, Doxycycline,ROLE OF ANTIBIOTICS,Therapeutic: To treat existing infectionProphylactic: To reduce the risk of wound infection,ANTIBIOTIC THERAPY,Pseudomembranous colitis- oral vancomycin/ metronidazoleBiliary-t
30、ract infection- cephalosporin or gentamycinPeritonitis- cephalosporin/ gentamycin + metronidazole/ clindamycinSepticemia- aminoglycoside + ceftazidime, Tazocin or imipenem, ( may add metronidazole ) Septicemia due to vascular catheter- Flucloxacillin/ vancomycin or Cefuroxime Cellulitis- penicillin,
31、 erythromycin ( flucloxacillin if Staphylococcus infection. Suspected ),ANTIBIOTIC PROPHYLAXIS BASED ON SURGICAL WOUND CLASSIFICATION,Clean wound - e.g., thyroid surgery ( 2% )Clean-contaminated- minimal contamination e.g., biliary, urinary, GI tract surgery ( 5-10% )Contaminated-gross contamination
32、 e.g., during bowel surgery- (up to 20% )Dirty- surgery through established infection e.g., peritonitis ( up to 50% ),ANTIBIOTIC PROPHYLAXIS,Prophylaxis in clean-contaminated/ high risk clean woundsAntibiotic is given just before patient sent for surgeryDuration of antibiotic is controversial ( one dose- 24 hour regimen ),Thank You!,
