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Chapter 8

Surgical Infections

Lena M. Napolitano

Key Points

1 Surgical infections include intra-abdominal infections (appendicitis, cholecystitis/cholangitis,

diverticulitis, colitis including C. difficile colitis, pancreatitis, and peritonitis), soft tissue infections

(necrotizing and nonnecrotizing), surgical site infections, and hospital-acquired infections that occur

in surgical patients (pneumonia, central line–associated bloodstream infections [CLABSI], and

catheter-associated urinary tract infections [CAUTI]).

2 Early empiric appropriate broad-spectrum antimicrobial therapy, to cover all potential causative

pathogens, is an important adjunct to source control in the treatment of surgical infections.

Inappropriate antimicrobial therapy is associated with increased mortality.

3 Any of these surgical infections can result in severe sepsis or septic shock.

4 A key concept in surgical infections is “source control,” defined as any physical intervention to

remove or eliminate a focus of invasive infection (drainage, debridement, and device removal) and

to restore optimal anatomic function.

5 Pathogen identification and appropriate deescalation of antimicrobial therapy are of paramount

importance in treatment of surgical infections, as increasing prevalence of multidrug-resistant

pathogens has been identified in both abdominal and skin surgical infections.

6 Complicated intra-abdominal infection (cIAI) extends beyond the hollow viscus of origin into the

peritoneal space and is associated with either abscess formation or peritonitis.

7 Recommendations for specific antimicrobial therapy for cIAI are based on whether the infection is

“community-acquired” or “healthcare-associated.”

8 In patients with intra-abdominal infections who have undergone an adequate source control

procedure, fixed-duration antibiotic therapy for 4 days is noninferior to longer duration

antimicrobial therapy until resolution of physiologic abnormalities, with no difference in surgical

site infection, recurrent intra-abdominal infection, or death.

9 The two surgical procedures indicated for C. difficile colitis treatment include (1) total abdominal

colectomy (for peritonitis, colonic perforation, ischemia, necrosis, toxic megacolon with impending

perforation, septic shock with organ failure) and (2) diverting loop ileostomy and intraoperative

colonic lavage for toxin reduction. The second option is associated with colonic preservation.

10 The initial treatment of infected pancreatic necrosis is percutaneous catheter or endoscopic

(transgastric/transduodenal) drainage with additional drain placement as required.

11 Lack of clinical improvement of necrotizing infected pancreatitis with initial percutaneous drainage

warrants consideration of minimally invasive techniques for pancreatic necrosectomy including

video-assisted retroperitoneal debridement, minimally invasive retroperitoneal pancreatectomy, or

transluminal direct endoscopic necrosectomy.

12 Acute bacterial skin and skin structure infections are defined as bacterial infection of the skin with a

lesion size area of at least 75 cm2 (lesion size measured by the area of redness, edema, or

induration), including cellulitis, wound infection, and abscess.

13 Early operative debridement is the major determinant of outcome in necrotizing soft tissue

infections. Delayed definitive debridement remains the single most important risk factor for death.

INTRODUCTION

1 Surgical infections include intra-abdominal infections (appendicitis, cholecystitis, diverticulitis, colitis,

and pancreatitis), soft tissue infections (necrotizing and nonnecrotizing), surgical site infections (SSIs),

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and hospital-acquired infections that occur in surgical patients (pneumonia, central line–associated

bloodstream infections [CLABSI], and catheter-associated urinary tract infections [CAUTI]).1

Appropriate therapy of surgical infections to optimize patient outcomes includes four steps: (1) early

diagnosis, (2) early initiation of appropriate empiric broad-spectrum antimicrobial therapy, (3)

adequate source control (surgical or interventional radiologic), and (4) pathogen identification and

appropriate deescalation of antimicrobial therapy (Table 8-1).

The initial management of all surgical infections should include the initiation of early empiric

antimicrobial therapy to cover all potential possible pathogens, since early and appropriate empiric

antibiotic therapy improves patient outcomes (Table 8-2).2 The choice of early empiric antimicrobial

therapy is guided by the specific site of infection, the common pathogens associated with that infection,

and by local and regional antibiograms. The goal of antimicrobial therapy is to achieve antibiotic levels

at the site of the infection that exceed the minimum inhibitory concentration of the microbial pathogens

present.

Early Use of Appropriate Broad-Spectrum Antimicrobial Therapy

2, 3 Early use of appropriate broad-spectrum antimicrobial therapy is an important adjunct to

appropriate surgical management of surgical infections. Numerous studies have confirmed that

inappropriate empiric antibiotics (i.e., antibiotics that do not cover the causative pathogens) are

associated with increased mortality.3 In patients who manifest severe sepsis or septic shock, every hour

delay of antimicrobial therapy is associated with increased mortality.4 The Surviving Sepsis Guidelines

recommendations are listed in Table 8-3.

Table 8-1 Appropriate Therapy of Surgical Infections

Source Control

4 Source control is defined as any physical intervention to remove or eliminate a focus of invasive

infection (drainage, debridement, and device removal) and to restore optimal anatomic function.5 In

surgical infections, antimicrobial agents are used in conjunction with adequate source control of the

initial infection. Adequate source control can be accomplished by either surgical or percutaneous

interventional radiologic techniques. A number of factors have been identified that predict failure of

source control for intra-abdominal infections (Table 8-4).

Pathogen Identification

5 Pathogen identification is extremely important, in part related to increased prevalence of multidrugresistant pathogens that are associated with surgical infections. Whenever possible, high-quality

specimens should be obtained from source control procedures for Gram stain and culture in order to

identify causative pathogens and determine antimicrobial susceptibility of the bacterial isolates

identified. This will enable appropriate deescalation of antimicrobial therapy from broad-spectrum

therapy to directed potential single antimicrobial agent therapy.

INTRA-ABDOMINAL INFECTIONS

Classification

6 Complicated intra-abdominal infection (cIAI) extends beyond the hollow viscus of origin into the

peritoneal space and is associated with either abscess formation or peritonitis. “Uncomplicated” intraabdominal infection involves intramural inflammation of the gastrointestinal tract and has a substantial

probability of progressing to cIAI if not adequately treated.

Table 8-2 Spectrum of Activity of Specific Antimicrobials for Specific Pathogens

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Table 8-3 Antimicrobial Therapy, Surviving Sepsis Guidelines 2012

Diagnosis

Patients with cIAI present with abdominal pain and gastrointestinal symptoms. A comprehensive

abdominal physical examination must be performed in these patients. If peritonitis is present, evaluation

for emergent laparotomy without diagnostic studies is considered. If peritonitis is not present, recent

evidence-based guidelines recommend that computed tomography (CT) scan of the abdomen and pelvis

is the diagnostic imaging modality of choice to evaluate for cIAI and its source.6,7

Treatment

7 Early empiric appropriate systemic antimicrobial therapy to cover all potential causative pathogens

and early source control are the mainstays of treatment of cIAIs. In order to select appropriate empiric

antimicrobial agents for use, cIAIs are further classified as “community-acquired” or “healthcareassociated.”

Community-Acquired Complicated Intra-Abdominal Infection

For patients who have “community-acquired” cIAI, determination of whether the disease is

“mild/moderate (appendicitis, mild diverticulitis)” or “severe (fecal peritonitis, perforated

diverticulitis)” facilitates appropriate antimicrobial treatment (Table 8-5). Patients with “severe”

community-acquired cIAI should have antibiotics that cover Pseudomonas and Enterococcus pathogens,

and both single-agent and combination-agent regimens are available for use. A number of antimicrobials

are no longer recommended for use in community-acquired cIAI:

Table 8-4 Clinical Factors Predicting Failure of “Source Control” for IntraAbdominal Infection

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