13- Surgical Infections

8/13/2019 13- Surgical Infections

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SURGICAL INFECTIONS AND

ANTIMICROBIAL TREATMENT


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1. Soft tissue infections

a. Cellulitis/lymphangitisb. Abscess

c. Necrotizing soft tissue infections; Clostridial/Non

clostridial

2. Body cavity infections ; Peritonitis

3. Close space infections

4. Prosthetic device-associate infections

5. Hospital acquired (Nosocomial) infections

6. Wound infections (SSI)


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Bacteria are classified according to staining

characteristics with Gram stain (positive or negative),

shape (cocci, rods, spirals), and ability to grow withoutoxygen (aerobic, facultative, anaerobic), or according to

a combination of these characteristics.

Gram-positive cocci, gram-negative aerobic and

facultative rods, and anaerobic bacteria are mostcommon bacteria causing surgical infections

Staph. aureus and strept. pyogenes are most common

surgical bacteriagram +ve aerobes

E.coli, klebsiella, pseudomnas, proteus..gramve

aerobes

B. fragilis, clostridia most common anaerobic in surgery


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SURGICAL INFECTIONS

Infections that require operative treatment or result

from operative treatment. Infections that

require operative treatment include

(1) necrotizing soft tissue infections;

(2) body cavity infections such as peritonitis,

suppurative pericarditis, and empyema(3) abscess and septic arthritis

(4) prosthetic deviceassociated infections.


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SOFT TISSUE INFECTIONS Cellutitis

Cellulitis is non suppurative bacterial infectionof the dermis and underlying subcutaneous

tissues of the skin.

Most commonly caused by Staph. aureus,MRSA and MSSA, Group A Beta hemolytic

streptococci, anaerobes, HIV, Cl Perfringens

History of trauma (hematoma), foreign body( foleys, prosthesis, clips, stents), surgery


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Characterized by;Local pain and tenderness, edema, and

erythema. Usually the border between infected and

uninvolved skin is indistinct and ill defined

ERYSIPELAS, which is caused by Strep. pyogenes,

is characterized by intense erythema with asharp line of demarcation between involved anduninvolved skin; high grade fever with chills,intense pain, and vomiting

Cellulitis may be accompanied by systemicmanifestations such as fever, chills,and malaise

Blood cultures are negative


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SOFT TISSUE INFECTIONS

ABSCESS

An abscess is a localized collection of pus in any part

of the body ,surrounded by swelling

Overlying erythema may lead to the mistaken

diagnosis of cellulitis, but the presence of a fluctuantmass is helpful

Most commonly caused by Staph. Aureus but

depends on sites; perianal, dental, etc

Swelling, pain, fever, redness, fluctuation, discharge

DIAGNOSIS; clinical, U/S, CT scan


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Types of abscess

CARBUNCLE is a subcutaneous abscess usuallyformed by a confluent infection of multiple

contiguous hair follicles. Most frequently found on

the back of the neck and on the upper back

FURUNCLE (BOIL) is an infected hair follicle, never

found on hairless skin

A FELON is a purulent collection in the distal phalanx

of the fingers that causes intense pain and pressurein that compartment


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Treatment of abscess

Incision/Drainage

Never close/stitch wound

Wash with N/S 8-12 hourly

Healing by secondary intention

Antobiotics


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SOFT TISSUE INFECTIONS

Necrotizing Soft Tissue Infection

Soft tissue infections that cause necrosis

Majority caused by mixed aerobic and anaerobic

gram-negative and gram-positive bacteria.

Clostridium species, esp. C. perfringens,

C. novyi, and C. septicum

Non clostridialby strept. pyogenes, klebsiella

High grade fever, skin necrosis skin crepitus,

(surgical emphysema), skin bullae,, septic shock


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Presence of gas in the soft tissues

Caused by an anaerobic, gram-positive, spore-forming

bacillus of the genus Clostridium.

C perfringens is the commonest. Other common

clostridial species include Clostridium septicum,Clostridium sporogenes, Clostridium histolyticum, and

Clostridium tertium

Non clostridial, gas forming bacteria; E. coli,

Klebsiella, pseudomonas

Hydrogen, nitrogen, and methane deposited in

tissues, produced by anaerobic bacterial metabolism

GAS GANGRENE; clostridial


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Clostridia secrete about 20 exotoxins which causetissue damage

Most important is alpha toxin.damages RBC,WBC, platelets, and muscle cells

Hemolysis, anemia, hypotension, and shock

Contamination of posttraumatic and portoperative wounds causes spore proliferation

Foreign bodies, premature wound closure, anddevitalized muscle prerequisites

Incubation period is frequently short (ie,


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CLINICAL FEATURES

Local swelling and a serosanguineous exudate appear soon

after the onset of pain. Skin turns to a bronze color, then progresses to a blue-

black color with skin blebs and hemorrhagic bullae.

Crepitus follows gas production

Pain and tenderness to palpation disproportionate to wound

appearance

Serosanginous, brown, sweet smelling exudate from the

wound is typically seen Tachycardia disproportionate to body temperaturre

Late signs of gas gangrene include hypotension, renal

failure, and confusional state


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Rpidly developing hemolytic anemia with an increased

lactate dehydrogenase (LDH) level

Despite serious infection, WBC remain normal

A Gram stain of the exudate or infected tissues reveals

gram-positive bacilli without neutrophils Less than 1% of blood cultures grow clostridial species

Metabolic acidosis and renal failure in ABGs

Alpha toxin blood levels through ELISA

PCR detetcs microbial DNA levels

IMAGING; Plain X ray, CT scan

Laboratory Studies
http://emedicine.medscape.com/article/201066-overviewhttp://emedicine.medscape.com/article/201066-overview


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TREATMENT Penicillin G 10-24 million U/d and clindamycin is widely

used Clindamycin and metronidazole for patients allergic to

penicillin

Hyper Baric Oxygen therapy; 100% oxygen at 2.5-3absolute atmospheres for 90-120 minutes 3 times a day

for 48 hours, then twice a day

Fasciotomy for compartment syndrome may be

necessary Daily debridement as needed to remove all necrotic

tissue.

Amputation of the extremity may be necessary


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PERITONITIS PRIMARY is caused by a single organism and occurs

most commonly in young children and in adults with

ascites or with renal failure

Treated with antibiotics and other medical measures

SECONDARY is caused by mixed flora and results from

an infective focus in GIT

Treated by surgery to remove septic focus, peritoneal

lavage, and drainage alongwith antibiotics Clinical Features same for both

DIAGNOSIS by clinical features and past medical history


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HOSPITAL ACQUIRED (Nosocomial)

INFECTIONS

1. Wound infections (SSI)

2. Urinary tract infections

3. Lower respiratory tract infections4. Vascular catheter related infections

5. Infected personnel


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SURGICAL SITE INFECTIONS (SSI) WOUND

INFECTIONS

Most SSIs are contaminated by patient's ownendogenous flora, which are present on the skin,mucous membranes, or hollow viscera

The most common bacteria responsible for SSIsare Staph.aureus, Staph. Epidermidis, gram veenteric bact.

Followed by anaerobic bacteria and MRSA

present in the skin Bacterial counts higher than 10,000 organisms

per gram of tissue is considered as SSI

T f SSI


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Types of SSISUPERFICIAL INCISIONAL SSI

Occurs within 30 days after the operation

Involves only the skin or subcutaneous tissue

DEEP INCISIONAL SSI

Occurs within 30 days of the operation or within 1 year if an

implant is present

Involves deep soft tissues (eg, fascia and/or muscle) of the

incision

ORGAN/SPACE SSI

Occurs within 30 days of the operation or within 1 year if animplant is present

Involves anatomical structures not opened or manipulated

during the operation

Superficial incisional SSI accounts for more than half of all SSIs


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Criteria for SSI

At least 1 of the following: Purulent drainage from the incision (culture

documentation not required)

Organisms are isolated from fluid/tissue of thesuperficial incision

At least 1 sign of inflammation (e.g, pain or

tenderness, induration, erythema, local warmth

of the wound) is present

The wound is deliberately opened by the

surgeon.


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T f S i l d


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Types of Surgical woundsTYPES OF SSI

CLASS I

Clean

Uninfected operative wound

No acute inflammationClosed primarily

Respiratory, gastrointestinal, biliary, and urinary tracts not

entered

CLASS II

Clean contaminated

Elective entry into biliary, gastrointestinal, urinary tracts and

with minimal spillageNo evidence of infection

Example: appendectomy

CLASS III

Contaminated

Nonpurulent inflammation present

Gross spillage from gastrointestinal tract

Penetrating traumatic wounds 4 hours


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On Examination; incision line swelling, oozing,

tender, red.stitches intact.fever,

tachycardia, generally unwell

CBC, C/S

PCR for microbial DNA

ELISA to detect bacterial antigens

Imaging; USG for superficial, CT scan for deep

Remove the stitches or apply more?

P h l i


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Prophylaxis

Prophylactic versus therapeutic antibiotics

Prophylactic Ax to be given 30 min-2 hours before surgery

To be used for all surgical wounds

Should not be continued beyond the operation day

Most common

Cephazolin/cefuroxime recommended

For colonic surgery add metronidazole

TREATMENT

Open the wound, remove stitches, pus and dead tissue, lookfor healthy and bleeding tissue..continue saline irrigation,

dressings and debrima

NO need for Ax once wound is opened


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Pre operative prophylaxisOperation Expected Pathogens Recommended Antibiotic

Orthopedic surgery S aureus Cefazolin 1-2 g

Appendectomy, biliary

procedures

Gram-negative bacilli and

anaerobes

Cefazolin 1-2 g

Colorectal surgery Gram-negative bacilli and

anaerobes

Cefotetan 1-2 g plus oral

neomycin 1 g and oral

erythromycin 1 gGastroduodenal surgery Gram-negative bacilli and

anaerobes

Cefazolin 1-2 g

Vascular surgery S aureus, Staphy.

epidermidis, gram-

negative bacilli

Cefazolin 1-2 g

Head and neck surgery S aureus, streptococci,

anaerobes

Cefazolin 1-2 g

Obstetric and

gynecological procedures

Gram-negative bacilli,

enterococci, anaerobes

Cefazolin 1-2 g

Urology procedures Gram negative bacilli Cefazolin 1 2 g

13- Surgical Infections

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