Open Access

Complicated intra-abdominal infections worldwide: the definitive data of the CIAOW Study

  • Massimo Sartelli1Email author,
  • Fausto Catena2,
  • Luca Ansaloni3,
  • Federico Coccolini3,
  • Davide Corbella4,
  • Ernest E Moore5,
  • Mark Malangoni6,
  • George Velmahos7,
  • Raul Coimbra8,
  • Kaoru Koike9,
  • Ari Leppaniemi10,
  • Walter Biffl5,
  • Zsolt Balogh11,
  • Cino Bendinelli11,
  • Sanjay Gupta12,
  • Yoram Kluger13,
  • Ferdinando Agresta14,
  • Salomone Di Saverio15,
  • Gregorio Tugnoli15,
  • Elio Jovine16,
  • Carlos A Ordonez17,
  • James F Whelan18,
  • Gustavo P Fraga19,
  • Carlos Augusto Gomes20,
  • Gerson Alves PereiraJunior21,
  • Kuo-Ching Yuan22,
  • Miklosh Bala23,
  • Miroslav P Peev7,
  • Offir Ben-Ishay13,
  • Yunfeng Cui24,
  • Sanjay Marwah25,
  • Sanoop Zachariah26,
  • Imtiaz Wani27,
  • Muthukumaran Rangarajan28,
  • Boris Sakakushev29,
  • Victor Kong30,
  • Adamu Ahmed31,
  • Ashraf Abbas32,
  • Ricardo Alessandro Teixeira Gonsaga33,
  • Gianluca Guercioni34,
  • Nereo Vettoretto35,
  • Elia Poiasina3,
  • Rafael Díaz-Nieto36,
  • Damien Massalou37,
  • Matej Skrovina38,
  • Ihor Gerych39,
  • Goran Augustin40,
  • Jakub Kenig41,
  • Vladimir Khokha42,
  • Cristian Tranà43,
  • Kenneth Yuh Yen Kok44,
  • Alain Chichom Mefire45,
  • Jae Gil Lee46,
  • Suk-Kyung Hong47,
  • Helmut Alfredo Segovia Lohse48,
  • Wagih Ghnnam32,
  • Alfredo Verni49,
  • Varut Lohsiriwat50,
  • Boonying Siribumrungwong51,
  • Tamer El Zalabany52,
  • Alberto Tavares53,
  • Gianluca Baiocchi54,
  • Koray Das55,
  • Julien Jarry56,
  • Maurice Zida57,
  • Norio Sato9,
  • Kiyoshi Murata58,
  • Tomohisa Shoko59,
  • Takayuki Irahara60,
  • Ahmed O Hamedelneel61,
  • Noel Naidoo62,
  • Abdul Rashid Kayode Adesunkanmi63,
  • Yoshiro Kobe64,
  • Wataru Ishii64, 65,
  • Kazuyuki Oka66,
  • Yoshimitsu Izawa67,
  • Hytham Hamid68,
  • Iqbal Khan68,
  • AK Attri13,
  • Rajeev Sharma13,
  • Juan Sanjuan17,
  • Marisol Badiel17 and
  • Rita Barnabé16
World Journal of Emergency Surgery20149:37

https://doi.org/10.1186/1749-7922-9-37

Received: 2 April 2014

Accepted: 11 May 2014

Published: 14 May 2014

Abstract

The CIAOW study (Complicated intra-abdominal infections worldwide observational study) is a multicenter observational study underwent in 68 medical institutions worldwide during a six-month study period (October 2012-March 2013). The study included patients older than 18 years undergoing surgery or interventional drainage to address complicated intra-abdominal infections (IAIs).

1898 patients with a mean age of 51.6 years (range 18-99) were enrolled in the study. 777 patients (41%) were women and 1,121 (59%) were men. Among these patients, 1,645 (86.7%) were affected by community-acquired IAIs while the remaining 253 (13.3%) suffered from healthcare-associated infections. Intraperitoneal specimens were collected from 1,190 (62.7%) of the enrolled patients.

827 patients (43.6%) were affected by generalized peritonitis while 1071 (56.4%) suffered from localized peritonitis or abscesses.

The overall mortality rate was 10.5% (199/1898).

According to stepwise multivariate analysis (PR = 0.005 and PE = 0.001), several criteria were found to be independent variables predictive of mortality, including patient age (OR = 1.1; 95%CI = 1.0-1.1; p < 0.0001), the presence of small bowel perforation (OR = 2.8; 95%CI = 1.5-5.3; p < 0.0001), a delayed initial intervention (a delay exceeding 24 hours) (OR = 1.8; 95%CI = 1.5-3.7; p < 0.0001), ICU admission (OR = 5.9; 95%CI = 3.6-9.5; p < 0.0001) and patient immunosuppression (OR = 3.8; 95%CI = 2.1-6.7; p < 0.0001).

Introduction

Intra-abdominal infections (IAIs) include a wide spectrum of pathological conditions, ranging from uncomplicated appendicitis to faecal peritonitis [1].

In the event of complicated IAI the infection proceeds beyond a singularly affected organ and causes either localized peritonitis (intra-abdominal abscesses) or diffuse peritonitis. Effectively treating patients with complicated intra-abdominal infections involves both source control and antimicrobial therapy [2, 3].

In order to describe the epidemiological, clinical, microbiological, and surgical treatment profiles of complicated intra-abdominal infections (IAIs) in Europe, the World Society of Emergency Surgery (WSES) designed the CIAO Study (Complicated intra-abdominal infections observational study). The CIAO Study was conducted during 2012 across twenty European countries [4].

Given the interesting results of the CIAO Study, WSES designed a prospective observational study investigating the management of complicated intra-abdominal infections in a worldwide context.

The CIAOW study (Complicated intra-abdominal infections worldwide observational study) is a multicenter observational study underwent in 68 medical institutions worldwide during a six-month study period (October 2012-March 2013).

In January 2013 the preliminary results (2-month study period) of the CIAOW study were published [5].

WSES presents the definitive data of the CIAOW Study.

Methods

Aim

The purpose of the study was to describe the clinical, microbiological, and treatment profiles of both community- and healthcare-acquired complicated IAIs in a worldwide context.

Patients older than 18 years with both community-acquired and healthcare-associated IAIs were included in the database.

Study population

The CIAOW study is a multicenter observational study underwent in 68 medical institutions worldwide. The study included patients undergoing surgery or interventional drainage to address complicated IAIs.

Medical institutions from each continent participated in the study. The geographical distribution of the participating centers are represented in Figure 1.
Figure 1

Participating centers for each continent.

Study design

The study did not attempt to change or modify the laboratory or clinical practices of the participating physicians, and neither informed consent nor formal approval by an Ethics Committee were required.

The study met the standards outlined in the Declaration of Helsinki and Good Epidemiological Practices.

The study was monitored by the coordination center, which investigated and verified missing or unclear data submitted to the central database. This study was performed under the direct supervision of the board of directors of WSES.

Data collection

In each centre, the coordinator collected and compiled data in an online case report system. These data included the following: (i) patient and disease characteristics, i.e., demographic data, type of infection (community- or healthcare-acquired), severity criteria, previous curative antibiotic therapy administered in the 7 days preceding surgery; (ii) origin of infection and surgical procedures performed; and (iii) microbiological data, i.e., identification of bacteria and microbial pathogens within the peritoneal fluid, the presence of yeasts (if applicable), and the antibiotic susceptibilities of bacterial isolates.

The primary endpoints included the following:

  • Clinical profiles of intra-abdominal infections

  • Epidemiological profiles (epidemiology of the microorganisms isolated from intra-abdominal samples and these organisms’ resistance to antibiotics)

  • Management profiles

Results

Patients

2,020 cases were collected in the online case report system. 122 cases did not meet the inclusion criteria.

1,898 patients with a mean age of 51.6 years (range 18-99) were enrolled in the CIAOW study. 777 patients (41%) were women and 1,121 (59%) were men. Among these patients, 1,645 (86.7%) were affected by community-acquired IAIs while the remaining 253 (13.3%) suffered from heathcare-associated infections. Intraperitoneal specimens were collected from 1,190 (62.7%) of the enrolled patients [213 patients (84.2%) with Healthcare-associated infections and 977 (59.4%) with Community-acquired infections].

827 patients (43.6%) were affected by generalized peritonitis while 1071 (56.4%) suffered from localized peritonitis or abscesses.

296 patients (14.2%) were admitted in critical condition (severe sepsis/septic shock).

Table 1, 2 overview the clinical findings and radiological assessments recorded upon patient admission.
Table 1

Clinical findings

Clinical findings

Patients

 

N 1898 (100%)

Abdominal pain

288 (15.1)

Abdominal pain, abdominal rigidity

284 (15%)

Abdominal pain, abdominal rigidity, T > 38°C or <36°C, WBC >12,000 or < 4,000

314 (16.5%)

Abdominal pain, abdominal rigidity, T > 38°C or <36°C,

67 (3.5)

Abdominal pain, abdominal rigidity, WBC >12,000 or < 4,000

376 (19.8%)

Abdominal pain, T > 38°C or <36°C,

68 (3.6%)

Abdominal pain, T > 38°C or <36°C, WBC >12,000 or < 4,000

139 (7.3%)

Abdominal pain, WBC >12,000 or < 4,000

266 (14%)

T > 38°C or <36°C

6 (0.3%)

T > 38°C or <36°C, WBC >12,000 or < 4,000

12 (0.6%)

Abdominal rigidity, WBC >12,000 or < 4,000

9 (0.5%)

Abdominal rigidity

2 (0.1%)

Abdominal rigidity, T > 38°C or <36°C

1 (0.05%)

Abdominal pain, abdominal rigidity, T > 38°C or <36°C, WBC >12,000 or < 4,000

7 (0.4%)

WBC >12,000 or < 4,000

11 (0.6%)

Not reported

48 (2.5%)

Table 2

Radiological procedures

Radiological procedures

Patients

 

N 1898 (100%)

Abdomen X ray

240 (12.6%)

Abdomen X ray, CT

102 (5.4%)

Abdomen X ray, ultrasound

356 (18.7%)

Abdomen X ray, ultrasound, CT

112 (5.9%)

Abdomen X ray, ultrasound, MRI

4 (0.2%)

Abdomen X ray, CT,ultrasound, MRI

7 (0.4%)

CT

426 (22.4%)

CT, MRI

2 (0.1%)

Ultrasound

384 (20.2%)

Ultrasound, CT

87 (4.6%)

Ultrasound, CT, MRI

1 (0.05%)

Ultrasound, MRI

3 (0.1%)

MRI

1 (0.05%)

Not reported

173 (9.1%)

Source control

The various sources of infection are outlined in Table 3. The most frequent source of infection was acute appendicitis; 633 cases (33.3%) involved complicated appendicitis.
Table 3

Source of infection

Source of infection

Patients

 

N 1898 (100%)

Appendicitis

633 (33.3%)

Cholecystitis

278 (14.6%)

Post-operative

170 (15.,9%)

Colonic non diverticular perforation

115 (9.9%)

Gastroduodenal perforations

253 (13.3%)

Diverticulitis

106 (5.6%)

Small bowel perforation

145 (7.6%)

Others

122 (6.4%)

PID

30 (1.6%)

Post traumatic perforation

46 (2.4%)

The open appendectomy was the most common means of addressing complicated appendicitis. 358 patients (56.5%) admitted for complicated appendicitis underwent open appendectomies: 276 patients (77.1%) for localized infection or abscesses and 82 patients (22.9%) for generalized peritonitis. A laparoscopic appendectomy was performed for 226 patients (35.7%) with complicated acute appendicitis; of these patients, 193 (85.4%) underwent the procedure for localized peritonitis/abscesses and 33 (14.6%) underwent the procedure for generalized peritonitis.

Open bowel resection was performed for 5 patients affected by complicated appendicitis. In the other 48 cases of complicated appendicitis (7.6%), conservative treatment (percutaneous drainage, surgical drainage, and non-operative treatment) was performed. 3% of patients underwent percutaneous drainage (17/513) to address appendicular abscesses or localized intra-abdominal infections.

Among the patients with complicated cholecystitis (278), the open cholecystectomy was the most frequently performed procedure. 47.8% (133) and % 36.7 (102) of cholecystitis patients underwent open and laparoscopic cholecystectomies, respectively. The remaining patients were treated with conservative methods (percutaneous drainage, non-operative treatment).

Among the patients with complicated diverticulitis (106) the Hartmann resection was the most frequently performed procedure. 48 patients (45.3%) underwent a Hartmann resection. 31 of these patients (64.6%) underwent a Hartmann resection for generalized peritonitis, while the remaining 17 (35.6%) underwent the same procedure for localized peritonitis or abscesses. Colo-rectal resection was performed in 18 cases (17%) (5 with and 13 without protective stoma).

The remaining patients received conservative treatment (percutaneous drainage, non-operative treatment, surgical drainage and stoma). 4 patients underwent laparoscopic drainage.

For patients with gastro-duodenal perforations (253 cases), the most common surgical procedure was gastro-duodenal suture. 212 patients underwent open gastro-duodenal suture (83.8%) and 18 patients underwent laparoscopic gastro-duodenal suture (7.1%). 12 patients (4.7%) underwent gastro-duodenal resection and 6 patients (2.4%) received conservative treatment. The remaining patients underwent alternative procedures.

Of the 145 patients with small bowel perforations, 98 underwent open small bowel resection (85.2%) and 3 (2%) underwent laparoscopic small bowel resection. 28 patients (19.3%) were treated by stoma.

Among the 115 patients with colonic non-diverticular perforation, 42 (36.5%) underwent Hartmann resection, 26 (22.6%) underwent open resection with anastomosis and without stoma protection, and 26 underwent open resection with stoma protection (22.6%).

170 cases (8.9%) were attributable to post-operative infections.

Source control was successfully implemented for 1,735 patients (91.4%).

Microbiology

Intraperitoneal specimens were collected from 1,190 patients (62.7%).

These specimens were obtained from 977 of the 1,645 patients presenting with community-acquired intra-abdominal infections (59.4%).

Intraperitoneal specimens were collected from 213 (84.2%) of the remaining 253 patients with nosocomial intra-abdominal infections.

The aerobic bacteria identified in intraoperative samples are reported In Table 4, 5.
Table 4

Aerobic bacteria identified from intra-operative peritoneal fluid

Total

1.330 (100%)

Aerobic Gram-negative bacteria

957 (71.9%)

Escherichia coli

548 (41.2%)

(Escherichia coli resistant to third generation cephalosporins)

75 (5.6%)

Klebsiella pneuumoniae

140 (10.5%)

(Klebsiella pneumoniae resistant to third generation cephalosporins)

26 (1.4%)

Klebsiella oxytoca

11 (0.8%)

(Klebsiella oxytoca resistant to third generation cephalosporins)

2 (0.1)

Enterobacter

64 (4.8%)

Proteus

47 (3.5%)

Pseudomonas

74 (5.6%)

Others

73 (5.6%)

Aerobic Gram-positive bacteria

373 (29.1%)

Enterococcus faecalis

153 (11.5%)

Enterococcus faecium

58 (4.4%)

Staphylococcus Aureus

38 (2.8%)

Streptococcus spp.

85 (6,4%)

Others

39 (2.9%)

Table 5

Aerobic bacteria from intra-operative samples in both community-acquired and healthcare-associated IAIs

Community-acquired IAIs

Isolates n°

Healthcare-associated (nosocomial) IAIs

Isolates n°

Aerobic bacteria

1030 (100%)

Aerobic bacteria

300 (100%)

Escherichia coli

456 (44.3%)

Escherichia coli

92 (21%)

(Escherichia coli resistant to third generation cephalosporins)

56 (5.4%)

(Escherichia coli resistant to third generation cephalosporins)

19 (6.3%)

Klebsiella pneumoniae

105 (10.1%)

Klebsiella pneumoniae

35 (11.7%)

(Klebsiella pneumoniae resistant to third generation cephalosporins)

11 (0.1%)

(Klebsiella pneumoniae resistant to third generation cephalosporins)

15 (5%)

Pseudomonas

56 (5.4%)

Pseudomonas

18 (5.7%)

Enterococcus faecalis

106 (10.3%)

Enterococcus faecalis

47 (15.7%)

Enterococcus faecium

38 (3.7%)

Enterococcus faecium

20 (6.7%)

The microorganisms isolated in subsequent samples from peritoneal fluid are reported in Table 6.
Table 6

Microorganisms identified from subsequent peritoneal samples

Total

268 (100%)

Aerobic Gram-negative bacteria

195 (72.7%)

Escherichia coli

105 (41.8%)

(Escherichia coli resistant to third generation cephalosporins)

35 (13.%)

Klebsiella pneuumoniae

41 (15.3%)

(Klebsiella pneumoniae resistant to third generation cephalosporins)

13 (4.8%)

Pseudomonas

20 (7.4%)

Others

29 (10.8%)

Aerobic Gram-positive bacteria

41 (15.3%)

Enterococcus faecalis

16 (6%)

Enterococcus faecium

10 (3.4%)

Staphylococcus Aureus

7 (4%)

Others

8 (3%)

Bacteroides

8 (3%)

Candida albicans

17 (6%)

Non candida albicans

6 (2.2%)

Other yeats

2 (0.7%)

All the microorganisms isolated in both intraoperative and subsequent samples from peritoneal fluid are reported in Table 7.
Table 7

Total of microorganisms identified from both intraoperative and subsequent peritoneal samples

Total

1826 (100%)

Aerobic Gram-negative bacteria

1152 (63%)

Escherichia coli

653 (35.7%)

(Escherichia coli resistant to third generation cephalosporins)

110 (6%)

Klebsiella pneuumoniae

181 (9.9%)

(Klebsiella pneumoniae resistant to third generation cephalosporins)

39 (2.1%)

Klebsiella oxytoca

11 (0.6%)

(Klebsiella oxytoca resistant to third generation cephalosporins)

2 (0.1)

Enterobacter

75 (4.1%)

Proteus

52 (2.8%)

Pseudomonas

94 (5.1%)

Others

102 (5.6%)

Aerobic Gram-positive bacteria

414 (22.7%)

Enterococcus faecalis

169 (9.2%)

Enterococcus faecium

68 (3.7%)

Staphylococcus Aureus

46 (2.5%)

Streptococcus spp.

85 (4.6%)

Others

47 (2.6%)

Anaerobes

141 (7.7%)

Bacteroides

108 (5.9%)

(Bacteroides resistant to Metronidazole)

3 (0.2%)

Clostridium

11 (0.6%)

Others

22 (1.2%)

Candida spp.

117 (6.4%)

Candida albicans

90 (4.9%)

(Candida albicans resistant to Fluconazole)

2 (0.1%)

Non-albicans Candida

27 (1.4%)

(non-albicans Candida resistant to Fluconazole)

3 (0.1%)

Other yeats

2 (0.1%)

The major pathogens involved in intra-abdominal infections were found to be Enterobacteriaceae.

Among the intra-operative isolates, Extended-Spectrum Beta-Lactamase (ESBL)-producing Escherichia coli isolates comprised 13.7% (75/548) of all Escherichia coli isolates, while ESBL-positive Klebsiella pneumoniae isolates represented 18.6% (26/140) of all Klebsiella pneumoniae isolates. ESBL-positive Enterobacteriaceae were more prevalent in patients with healthcare associated infections IAIs than they were in patients with community-acquired IAIs. ESBL-positive Escherichia coli isolates comprised 20.6% (19/92) of all identified Escherichia coli isolates, while ESBL-positive Klebsiella pneumoniae isolates made up 42.8% (15/35) of all identified Klebsiella pneumoniae isolates.

Among all the microorganisms isolated in both intraoperative and subsequent samples from peritoneal fluid, there were 110 isolates of Escherichia coli ESBL, 39 isolates of Klebsiella pneumoniae ESBL, 2 isolates of Klebsiella Oxytoca ESBL. There were 5 isolates of Klebsiella pneumoniae resistant to Carbapenems.

Among the microorganisms isolated in the intraoperative samples, there were 74 isolates of Pseudomonas aeruginosa, comprising 5.6% of all aerobic identified bacteria isolates.

Among all the microorganisms isolated in both intraoperative and subsequent samples from peritoneal fluid, there were 94 isolates of Pseudomonas aeruginosa, comprising 5.1% of all identified bacteria isolates.

The 2 Pseudomonas aeruginosa strains resistant to Carbapenems were also obtained from nosocomial infections.

Among all the aerobic gram-positive bacteria identified in the intraoperative samples, Enterococci (E. faecalis and E. faecium) were the most prevalent, representing 15.9% of all aerobic isolates, and were identified in 211 cases. Although Enterococci were also present in community-acquired infections, they were more prevalent in healthcare-associated infections (31.7%: 67/211).

Among all the microorganisms isolated in both intraoperative and subsequent samples from peritoneal fluid Enterococci were 237/1826 (12.9%).

11 glycopeptide-resistant Enterococci were identified; 5 were glycopeptide-resistant Enterococcus faecalis isolates and 6 were glycopeptide-resistant Enterococcus faecium isolates.

Tests for anaerobes were conducted for 486 patients.

Identified anaerobic bacteria from intra-operative specimens are reported in Table 8.
Table 8

Anaerobic bacteria identified from intra-operative peritoneal fluid

Anaerobes

133

Bacteroides

100 (75%)

(Bacteroides resistant to Metronidazole)

3 (1.5%)

Clostridium

11 (8.2%)

Others

22 (16.5%)

Among all the microorganisms isolated in both intraoperative and subsequent samples from peritoneal fluid, 141 anaerobes were observed. The most frequently identified anaerobic pathogen was Bacteroides. 108 Bacteroides isolates were observed during the course of the study.

In Table 9 are illustrated Candida spp. isolated in intra-operative specimens.
Table 9

Candida isolates identified from intra-operative peritoneal fluid

Candida spp.

94

Candida albicans

73 (78.7%)

(Candida albicans resistant to Fluconazole)

2 (2.1%)

Non-albicans Candida

21 (19.1%)

(non-albicans Candida resistant to Fluconazole)

3 (3.2%)

Among all the microorganisms isolated in both intraoperative and subsequent samples from peritoneal fluid, 117 Candida isolates were collectively identified (6%). 90 were Candida albicans and 27 were non-albicans Candida.

Outcome

The overall mortality rate was 10.5% (199/1898).

565 patients (29.8%) were admitted to the intensive care unit (ICU) in the early recovery phase immediately following surgery.

223 patients (11.7%) ultimately required additional surgeries. 62 (11.3%) of these patients underwent open abdominal procedures.

In the immediate post-operative clinical period 269 patients were critically ill (132 with septic shock, 137 with severe sepsis).

According to univariate statistical analysis of the data (Table 10), septic shock (OR = 14.9; 95%CI = 9.3-26.7; p < 0.0001) and severe sepsis (OR = 4.2; 95%CI = 2.8-6.3; p < 0.0001) upon hospital admission were both predictive of patient mortality.
Table 10

Univariate analysis: risk factors for occurrence of death during hospitalization

Risk factors

Odds ratio

95%CI

p

Clinical condition upon hospital admission

   

Severe sepsis

27.6

15.9-47.8

<0.0001

Septic shock

14.6

8.7-24.4

<0.0001

Healthcare associated infection

3.1

2.2-4.5

<0.0001

Source of infection

   

Colonic non-diverticular perforation

21

9.9-44.6

<0.0001

Small bowel perforation

125.7

29.1-542

<0.0001

Complicated diverticulitis

11

4.9-25.2

<0.0001

Post-operative infections

19.1

9.3-39.3

<0.0001

Delayed initial intervention

2.6

1.8-3.5

<0.0001

Immediate post-operative clinical course

   

Severe sepsis

33.8

19.5-58.4

<0.0001

Septic shock

59.2

34.4-102.1

<0.0001

ICU admission

18.6

12-28.7

<0.0001

Comorbidities

   

Malignancy

3.6

2.5-15.1

p < 0.0001

Immunosoppression

1.0

3.2-7.5

p < 0.0001

Serious cardiovascular disease

4.5

3.2-6.3

p < 0.0001

The setting of acquisition was also a variable found to be predictive of patient mortality (healthcare-associated infections: OR = 3.1; 95%CI = 2.2-4.5; p < 0.0001).

Among the various sources of infection, colonic non-diverticular perforation (OR = 21; 95%CI = 9.9-44.6 p < 0.0001), complicated diverticulitis (OR = 11; 95%CI = 4.9-25.2; p < 0.0001), small bowel perforation (OR = 14.3; 95%CI = 6.7-30.3; p < 0.0001) and post-operative infections (OR = 19.1; 95%CI = 9.3-39.3; p < 0.0001) were significantly correlated with patient mortality.

Mortality rates did not vary to a statistically significant degree between patients who received adequate source control and those who did not. However, a delayed initial intervention (a delay exceeding 24 hours) was associated with an increased mortality rate (OR = 3.6; 95%CI = 1.9-3.7; p < 0.0001).

The nature of the immediate post-operative clinical period was a significant predictor of mortality (severe sepsis: OR = 10.5; 95%CI = 24.0-66.0; p < 0.0001, septic shock: OR = 39.8; 95%CI = 6.4-17.5; p < 0.0001). Patients requiring ICU admission (OR = 12.9; 95%CI = 8.8-19.0; p < 0.0001) were also associated with increased mortality rates.

Also comorbidities were associated to patient mortality (Malignancy: OR = 3.6; 95%CI = 2.5-15.1; p < 0.0001, immunosuppression: OR = 1.0; 95%CI = 3.2-7.5; p < 0.0001, and serious cardiovascular disease: OR = 4.5; 95%CI = 3.2-6.3, p < 0.0001).

According to stepwise multivariate analysis (PR = 0.005 and PE = 0.001) (Table 11), several criteria were found to be independent variables predictive of mortality, including patient age (OR = 1.1; 95%CI = 1.0-1.1; p < 0.0001), the presence of small bowel perforation: OR = 2.8; 95%CI = 1.5-5.3; p < 0.0001), a delayed initial intervention (a delay exceeding 24 hours) (OR = 1.8; 95%CI = 1.5-3.7; p < 0.0001), ICU admission (OR = 5.9; 95%CI = 3.6-9.5; p < 0.0001) and patient immunosuppression (OR = 3.8; 95%CI = 2.1-6.7; p < 0.0001).
Table 11

Multivariate analysis: risk factors for occurrence of death during hospitalization

Risk factors

Odds ratio

95%CI

p

Age

3.3

2.2-5

<0.0001

Small bowel perforation

27.6

15.9-47.8

<0.0001

Delayed initial intervention

14.6

8.7-24.4

<0.0001

ICU admission

2.3

1.5-3.7

<0.0001

Immunosuppression

3.8

2.1-6.7

<0.0001

Stepwise multivariate analysis, PR = 0.005 E PE = 0.001 (Hosmer-Lemeshow chi2(8) = 1.68, area under ROC curve = 0.9465).

Discussion

The CIAOW Study confirmed that acute appendicitis is the most common intra-abdominal condition requiring emergency surgery worldwide. According to the WSES 2013 guidelines for management of intra-abdominal infections, both open and laparoscopic appendectomies are viable treatment options for complicated appendicitis [6]. CIAOW Study results indicate that the open approach was used in most patients and it was the most common approach in the patients with complicated appendicitis.

For patients with peri-appendiceal abscesses, the proper course of surgical treatment remains a point of contention in the medical community. Although guidelines for the management of intra-abdominal infections commonly assert that patients with peri-appendiceal abscesses should be treated with percutaneous image-guided drainage [5]. Percutaneous drainage with or without interval appendectomy to treat peri-appendiceal abscess results in fewer complications and shorter overall length of stay [68]. Data from CIAOW Study indicate that few patients underwent this procedure for a peri-appenceal abscess.

Laparoscopic cholecystectomy versus open cholecystectomy question for acute cholecystitis has been extensively investigated. Several studies showed that early laparoscopic cholecystectomy resulted in a significantly reduced length of stay, no major complications, and no significant difference in conversion rates when compared with initial antibiotic treatment and delayed laparoscopic cholecystectomy [912].

The open cholecystectomy was the most common means of treating complicated cholecystitis; 47.8% (133) of the patients with complicated cholecystitis underwent this procedure. By contrast, 36.7% (102) underwent a laparoscopic procedure.

The optimal surgical management of colonic diverticular disease complicated by peritonitis remains a controversial issue. Hartmann’s resection has been considered the procedure of choice in patients with generalized peritonitis and remains a safe technique for emergency colectomy in perforated diverticulitis, especially in elderly patients with multiple co-morbidities [13]. More recently, some reports have suggested that primary resection and anastomosis is the preferred approach to diverticulitis, even in the presence of diffuse peritonitis [14, 15].

According to CIAOW Study data, the Hartmann resection was the most frequently performed procedure to address both complicated diverticulitis and non-diverticular colonic perforations worldwide.

The significance of microbiological analysis of infected peritoneal fluid in community-acquired intra-abdominal infections has been debated in recent years.

Although the absence of impact of bacteriological cultures has been documented especially in appendicitis [16], in this era of the broad spread of resistant microorganisms such as nosocomial and community extended-spectrum b-lactamase (ESBL) Enterobacteriaceae, carbapenemase producing gram negatives, b lactam- and vancomycin resistant enterococci (VRE), the threat of resistance is a source of major concern for clinicians. Therefore the results of the microbiological analyses have great importance for the therapeutic strategy of every patients.

According to CIAOW Study data, intraperitoneal specimens were collected from 62.7% of patients with complicated intra-abdominal infections.

Intraperitoneal specimens were collected in 59.4% patients presenting with community-acquired intra-abdominal infections.

Intraperitoneal specimens were collected from 84.2% of the patients with nosocomial intra-abdominal infections.

In many clinical laboratories, species identification and susceptibility testing of anaerobic isolates are not routinely performed. Tests for anaerobes were conducted for 486 patients.

The major pathogens involved in community-acquired intra-abdominal infections are Enterobacteriaceae, Streptococcus species, and certain anaerobes (particularly B. fragilis).

The main resistance threat in intra.-abdominal infections is posed by ESBL-producing Enterobacteriaceae, which are becoming increasingly common in community-acquired infections [17, 18].

According to CIAOW Study data, ESBL producers were the most commonly identified drug-resistant microorganism involved in IAIs.

Recent years have seen an escalating trend of Klebsiella pneumoniae Carbapenemase (KPC) production, which continues to cause serious multidrug-resistant infections around the world. The recent emergence of Carbapenem-resistant Enterobacteriaceae is a major threat to hospitalized patients [19].

5 identified isolates of Klebsiella pneumoniae proved resistant to Carbapenems.

Pseudomonas aeruginosa is one of the major nosocomial pathogens worldwide. It is intrinsically resistant to many drugs and is able to become resistant to virtually any antimicrobial agent.

The rate of Pseudomonas aeruginosa was 5.6% of all microorganisms isolated in the intra-operative samples. According to CIAOW study there was no significant difference between community and healthcare associate infections.

The 2 Pseudomonas aeruginosa strains resistant to Carbapenems were also obtained from nosocomial infections.

Enterococci are significant pathogens in intra-abdominal infections. Among multidrug Gram positive bacteria, Enterococci remain a challenge. The evolution of antimicrobial resistance in these organisms poses enormous challenges for clinicians when faced with patients affected with Enterococcus infections. Enterococcus infections are difficult to treat because of both intrinsic and acquired resistance to many antibiotics.

Enterococci (E. faecalis and E. faecium) were the most common Gram positive aerobic isolates.

Although Enterococci were also identified in community-acquired infections, they were far more prevalent in nosocomial infections.

In the last years there has been a significant increase in the incidence of invasive infections due to Candida species.

Although the epidemiological role of Candida spp. in nosocomial peritonitis is not yet defined, the clinical role is significant, because Candida isolation is normally associated to a poor prognosis [20].

In the CIAOW Study 117 Candida isolates were collectively identified (6%). 90 were Candida albicans and 27 were non-albicans Candida.

It is well known that patients with severe sepsis or septic shock may be complicated by high mortality rates. According to the CIAOW Study the overall mortality rate was 10.5% (199/1898).

29.8% of patients were admitted to the ICU in the early recovery phase immediately following surgery. In the immediate post-operative clinical period 269 patients were critically ill (132 with septic shock, 137 with severe sepsis).

The surgical treatment strategies following an initial emergency laparotomy have been debated in the last years.

The decision whether and when to perform a relaparotomy in secondary peritonitis is largely subjective and based on professional experience. Factors indicative of progressive or persistent organ failure during early postoperative follow-up are the best indicators for ongoing infection and associated positive findings at relaparotomy [2123].

Relaparotomy strategies may include either a relaparotomy, when the patient's condition demands it ("relaparotomy on-demand"), or a planned relaparotomy with temporarily abdomen closure or open abdomen [2427].

In the CIAOW Study 223 post-operative patients (11.7%) ultimately required additional surgeries. 62 (11.3%) of these patients underwent open abdominal procedures.

According to univariate statistical analysis of the data, septic shock and severe sepsis upon hospital admission were both predictive of patient mortality.

The setting of acquisition was also a variable found to be predictive of patient mortality (healthcare-associated infections).

Among the various sources of infection, colonic non-diverticular perforation, complicated diverticulitis, small bowel perforation and post-operative infections were significantly correlated with patient mortality.

Mortality rates did not vary to a statistically significant degree between patients who received adequate source control and those who did not. However, a delayed initial intervention (a delay exceeding 24 hours) was associated with an increased mortality rate.

The nature of the immediate post-operative clinical period was a significant predictor of mortality. Patients requiring ICU admission were also associated with increased mortality rates.

Also comorbidities were associated to patient mortality.

According to stepwise multivariate analysis, several criteria were found to be independent variables predictive of mortality, including patient age, the presence of small bowel perforation, a delayed initial intervention (a delay exceeding 24 hours), ICU admission and patient immunosuppression.

Conclusion

Complicated intra-abdominal infections remain an important source of patient morbidity and are frequently associated with poor clinical prognoses, particularly for patients in high-risk categories.

Given the sweeping geographical distribution of the participating medical centers, the CIAOW Study gives an accurate description of the epidemiological, clinical, microbiological, and treatment profiles of complicated intra-abdominal infections worldwide.

Declarations

Authors’ Affiliations

(1)
Department of Surgery, Macerata Hospital
(2)
Emergency Surgery, Maggiore Parma Hospital
(3)
Department of General Surgery, Ospedali Riuniti
(4)
Department of Anestesiology, Ospedali Riuniti
(5)
Department of Surgery, Denver Health Medical Center
(6)
American Board of Surgery
(7)
Division of Trauma, Emergency Surgery and Surgical Critical Care, Harvard Medical School, Massachusetts General Hospital
(8)
Department of Surgery, UC San Diego Health System
(9)
Department of Primary Care & Emergency Medicine, Kyoto University Graduate School of Medicine
(10)
Department of Abdominal Surgery, University Hospital Meilahti
(11)
Department of Surgery, University of Newcastle
(12)
Department of Surgery, Govt Medical College and Hospital
(13)
Department of General Surgery, Rambam Health Care Campus
(14)
Department of Surgery, Adria Hospital Adria
(15)
Trauma Surgery Unit, Maggiore Hospital
(16)
Department of Surgery, Maggiore Hospital
(17)
Department of Surgery, Fundación Valle del Lilí
(18)
Division of Trauma/Critical Care Department of Surgery Virginia Commonwealth University
(19)
Division of Trauma Surgery, Campinas University
(20)
Department of Surgery, Monte Sinai Hospital
(21)
Department of Surgery, Emergency Unit
(22)
Department of Surgery, Chang Gung Memorial Hospital
(23)
Department of General Surgery, Hadassah Medical Center
(24)
Department of Surgery, Tianjin Nankai Hospital, Nankai Clinical School of Medicine, Tianjin Medical University
(25)
Department of Surgery, Pt BDS Post-graduate Institute of Medical Sciences
(26)
Department of Surgery, MOSC Medical College
(27)
Department of Surgery, SKIMS
(28)
Department of Surgery, Kovai Medical Center
(29)
First Clinic of General Surgery, University Hospital/UMBAL/St George Plovdiv
(30)
Department of Surgery, Edendale Surgery
(31)
Department of Surgery, Ahmadu Bello University Teaching Hospital Zaria
(32)
Department of Surgery, Mansoura University Hospital
(33)
Department of Surgery, Faculdades Integradas Padre Albino
(34)
Department of Surgery, Mazzoni Hospital
(35)
Department of Surgery, Mellini Hospital
(36)
Department of General and Digestive Surgery, Virgen de la Victoria, University Hospital
(37)
Department of General Surgery and Surgical Oncology, Université de Nice Sophia-Antipolis, Universitary Hospital of Nice
(38)
Department of Surgery, Hospital and Oncological Centre
(39)
Department of General Surgery, Lviv Emergency Hospital
(40)
Department of Surgery, University Hospital Center Zagreb
(41)
3rd Department of General Surger Jagiellonian Univeristy, Narutowicz Hospital
(42)
Department of Surgery, Mozyr City Hospital
(43)
Department of Surgery, Ancona University
(44)
Department of Surgery, Ripas Hospital
(45)
Clinical Sciences, Regional Hospitals Limbe and Buea
(46)
Department of Surgery, Severance Hospital, Yonsei University College of Medicine
(47)
Division of Trauma and Surgical Critical Care, Department of Surgery, University of Ulsan
(48)
II Cátedra de Clínica Quirúrgica, Hospital de Clínicas
(49)
Department of Surgery, Cutral Có Clinic
(50)
Department of Surgery, Faculty of Medicine Siriraj Hospital
(51)
Department of Surgery, Thammasat University Hospital
(52)
Department of Surgery, Bahrain Defence Force Hospital
(53)
Department of Surgery, Hospital Regional de Alta Especialidad del Bajio
(54)
Clinical and Experimental Sciences, Brescia Ospedali Civili
(55)
General Surgery, Adana Numune Training and Research Hospital
(56)
Visceral Surgery, Military Hospital Desgenettes
(57)
Visceral Surgery, Teaching Hospital Yalgado Ouedraogo
(58)
Department of Acute and Critical care medicine, Tokyo Medical and Dental University
(59)
The Shock Trauma and Emergency Medical Center, Matsudo City Hospital
(60)
Emergency and Critical Care Center of Nippon Medical School, Tama-Nagayama Hospital
(61)
Department of Surgery, Our Lady of Lourdes Hospital
(62)
Department of Surgery, Port Shepstone Hospital
(63)
Department of Surgery, Obafemi Awolowo UNiversity Hospital
(64)
Department of Emergency and Critical Care Medicine, Chiba University Hospital
(65)
Depatment of Emergency Medicine, Kyoto Second Red Cross Hospital
(66)
Tajima emergency & Critical Care Medical Center, Toyooka Public Hospital
(67)
Emergency and Critical Care Medicine, Jichi Medical University
(68)
Department of Surgery, Mayo General Hospital Castlebar Co. Mayo

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© Sartelli et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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