Diagnosis and Management of Complicated Intra-abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

[Minimally invasive surgical therapy of acute cholecystitis]

Acute cholecystitis is the most common complication of cholecystolithiasis. It develops in about 10 % of symptomatic patients and gangrenous cholecystitis, gallbladder perforation, gallbladder empyema, or abscesses are typical complications. Cholecystectomy is the most relevant therapy to achieve pain reduction, to prevent the progression of inflammation or local complications and to minimize the risk of recurrence. Surgical therapy can be supported by medical and interventional treatment modalities depending on the severity of the disease. The present review summarizes the surgical aspects in acute cholecystitis with a focus on laparoscopic cholecystectomy which is the gold standard of therapy.

Inoculum effect on the efficacies of amoxicillin-clavulanate, piperacillin-tazobactam, and imipenem against extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing Escherichia coli in an experimental murine sepsis model

Escherichia coli is commonly involved in infections with a heavy bacterial burden. Piperacillin-tazobactam and carbapenems are among the recommended empirical treatments for health care-associated complicated intra-abdominal infections. In contrast to amoxicillin-clavulanate, both have reduced in vitro activity in the presence of high concentrations of extended-spectrum β-lactamase (ESBL)-producing and non-ESBL-producing E. coli bacteria. Our goal was to compare the efficacy of these antimicrobials against different concentrations of two clinical E. coli strains, one an ESBL-producer and the other a non-ESBL-producer, in a murine sepsis model. An experimental sepsis model {~5.5 log10 CFU/g [low inoculum concentration (LI)] or ~7.5 log(10) CFU/g [high inoculum concentration (HI)]} using E. coli strains ATCC 25922 (non-ESBL producer) and Ec1062 (CTX-M-14 producer), which are susceptible to the three antimicrobials, was used. Amoxicillin-clavulanate (50/12.5 mg/kg given intramuscularly [i.m.]), piperacillin-tazobactam (25/3.125 mg/kg given intraperitoneally [i.p.]), and imipenem (30 mg/kg i.m.) were used. Piperacillin-tazobactam and imipenem reduced spleen ATCC 25922 strain concentrations (-2.53 and -2.14 log10 CFU/g [P < 0.05, respectively]) in the HI versus LI groups, while amoxicillin-clavulanate maintained its efficacy (-1.01 log10 CFU/g [no statistically significant difference]). Regarding the Ec1062 strain, the antimicrobials showed lower efficacy in the HI than in the LI groups: -0.73, -1.89, and -1.62 log10 CFU/g (P < 0.05, for piperacillin-tazobactam, imipenem, and amoxicillin-clavulanate, respectively, although imipenem and amoxicillin-clavulanate were more efficacious than piperacillin-tazobactam). An adapted imipenem treatment (based on the time for which the serum drug concentration remained above the MIC obtained with a HI of the ATCC 25922 strain) improved its efficacy to -1.67 log10 CFU/g (P < 0.05). These results suggest that amoxicillin-clavulanate could be an alternative to imipenem treatment of infections caused by ESBL- and non-ESBL-producing E. coli strains in patients with therapeutic failure with piperacillin-tazobactam.

Comparative study of the efficacy and safety of ceftazidime/avibactam plus metronidazole versus meropenem in the treatment of complicated intra-abdominal infections in hospitalized adults: results of a randomized, double-blind, Phase II trial

OBJECTIVES

Avibactam, a novel non-β-lactam β-lactamase inhibitor, restores the in vitro activity of ceftazidime against class A, C and some class D β-lactamase-producing pathogens, including those commonly associated with complicated intra-abdominal infections (cIAIs). This randomized, active-controlled, double-blind, Phase II trial (NCT00752219) aimed to evaluate the safety and efficacy of ceftazidime/avibactam plus metronidazole compared with meropenem in hospitalized patients with cIAI.

METHODS

Adults with confirmed cIAI requiring surgical intervention and antibiotics were randomized 1 : 1 to receive intravenously either (i) 2000 mg of ceftazidime plus 500 mg of avibactam plus a separate infusion of 500 mg of metronidazole or (ii) 1000 mg of meropenem plus placebo every 8 h for a minimum of 5 days and a maximum of 14 days. The primary efficacy endpoint was the clinical response in microbiologically evaluable (ME) patients at the test-of-cure (TOC) visit 2 weeks after the last dose of study therapy.

RESULTS

Overall, 101 patients received ceftazidime/avibactam plus metronidazole; 102 received meropenem. The median duration of treatment was 6.0 and 6.5 days, respectively. Favourable clinical response at the TOC visit in the ME population was observed in 91.2% (62/68) and 93.4% (71/76) of patients in the ceftazidime/avibactam plus metronidazole and meropenem groups, respectively (observed difference: -2.2%; 95% CI: -20.4%, 12.2%). The incidence of treatment-emergent adverse events was similar for ceftazidime/avibactam plus metronidazole (64.4%) and meropenem (57.8%).

CONCLUSIONS

Ceftazidime/avibactam plus metronidazole was effective and generally well tolerated in patients with cIAI, with a favourable clinical response rate in the ME population of >90%, similar to that of meropenem.

Intraabdominal Infections in the Intensive Care Unit

Intraabdominal infections are frequent and dangerous entity in intensive care units. Mortality and morbidity are high, causes are numerous, and treatment options are variable. The intensivist is challenged to recognize and treat intraabdominal infections in a timely fashion to prevent complications and death. Diagnosis of intraabdominal infection is often complicated by confounding underlying disease or masked by overall comorbidity. Current research describes a wide heterogeneity of patient populations, making it difficult to suggest a general treatment regimen and stressing the need of an individualized approach to decision making. Early focus-oriented intervention and antibiotic coverage tailored to the individual patient and hospital is warranted.

Emergency department observation units and the older patient

An increasing number of emergency departments (EDs) are providing extended care and monitoring of patients in ED observation units (EDOUs). EDOUs can be useful for older adults as an alternative to hospitalization and as a means of risk stratification for older adults with unclear presentations. They can also provide a period of therapeutic intervention and reassessment for older patients in whom the appropriateness and safety of immediate outpatient care are unclear. This article discusses the general characteristics of EDOUs, reviews appropriate entry and exclusion criteria for older adults in EDOUs, and discusses regulatory implications of observation status for patients with Medicare.

Optimizing drug therapy in the surgical intensive care unit

This article provides a review of commonly prescribed medications in the surgical ICU, focusing on sedatives, antipsychotics, neuromuscular blocking agents, cardiovascular agents, anticoagulants, and antibiotics. A brief overview of pharmacology is followed by practical considerations to aid prescribers in selecting the best therapy within a given category of drugs to optimize patient outcomes.

Postoperative peritonitis without an underlying digestive fistula after complete cytoreductive surgery plus HIPEC

BACKGROUND/AIM

Peritoneal carcinomatosis (PC) is a pernicious event associated with a dismal prognosis. Complete cytoreductive surgery (CCRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is able to yield an important survival benefit but at the price of a risky procedure inducing potentially severe complications. Postoperative peritonitis after abdominal surgery occurs mostly when the digestive lumen and the peritoneum communicate but in rare situation, no underlying digestive fistula can be found. The aim of this study was to report this situation after CCRS plus HIPEC, which has not been described yet and for which the treatment is not yet well defined.

PATIENTS AND METHODS

Between 1994 and 2012, 607 patients underwent CCRS plus HIPEC in our tertiary care center and were retrospectively analyzed.

RESULTS

Among 52 patients (9%) reoperated for postoperative peritonitis, no digestive fistula was found in seven (1%). All had a malignant peritoneal pseudomyxoma with an extensive disease (median Peritoneal Cancer Index: 27). The median interval between surgery and reoperation was 8 days [range: 3-25]. Postoperative mortality was 14%. Five different bacteriological species were identified in intraoperative samples, most frequently Escherichia coli (71%). The infection was monobacterial in 71%, with multidrug resistant germs in 78%.

CONCLUSIONS

Postoperative peritonitis without underlying fistula after CCRS plus HIPEC is a rare entity probably related to bacterial translocation, which occurs in patients with extensive peritoneal disease requiring aggressive surgeries. The principles of treatment do not differ from that of other types of postoperative peritonitis.

Superiority of ceftriaxon to cefazolin in a rat model of obstructive jaundice: an experimental study

OBJECTIVE

The objective of this study was to evaluate the serum and bile concentrations of cefazolin and ceftriaxone at the third and sixth hours in an experimental obstructive jaundice model and to identify the rate of excretion of these antibiotics into the bile.

MATERIAL AND METHODS

Thirty-two Wistar albino rats were used in this study. The bile and serum levels of cefazolin were measured at the third hour in the A1 group and at the sixth hour in the A2 group, with cefazolin administered as 5 mg/rat; while the bile and serum levels of ceftriaxone were studied at the third hour in the B1 group and at the sixth hour in the B2 group, with ceftriaxone administered as 5 mg/rat.

RESULTS

After 3 hr of cefazolin administration, the serum concentration in the A1 group reached a mean of 1.8 μg/ml, while the bile concentration was 90% of the serum concentration, with a mean of 1.6 μg/ml; whereas in the B1 group, the third-hour serum concentration of ceftriaxone was 18.6 μg/ml, while the bile concentration was found to be as high as 330% of this level, i.e., 56 μg/ml. The serum value of cefazolin decreased to 1.4 μg/ml in the A2 group and ceftriaxone decreased to 3.7 μg/ml in the B2 group at the sixth hour.

CONCLUSIONS

Although the excretory level of cefazolin and ceftriaxone into the bile reaches therapeutic doses, the duration for which these levels are above those required for bactericidal activity is short. Ceftriaxone is better concentrated in the serum and bile than cefazolin.

Changing bacteriology of abdominal and surgical sepsis

PURPOSE OF REVIEW

This review focuses on recent changes in epidemiological aspects of bacteria-induced intra-abdominal infections (IAIs), including the dominant pathogens, antimicrobial susceptibility profiles, and emerging resistance phenotypes.

RECENT FINDINGS

Enterobacteriaceae species, including Escherichia coli and Klebsiella pneumoniae, remain the major pathogens contributing to abdominal sepsis, although Pseudomonas aeruginosa and Acinetobacter baumannii have recently become common causes of hospital-acquired IAIs. The prevalence of multidrug-resistant Gram-negative bacilli, especially those that produce extended-spectrum β-lactamases (ESBLs), has increased worldwide, although the distribution of those organisms varies from region to region. Furthermore, recent changes in interpretive breakpoints for antimicrobial susceptibility testing recommended by the Clinical Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) have resulted in a marked increase in the reported rates of resistance among Gram-negative bacilli to carbapenems, extended-spectrum cephalosporins, and fluoroquinolones. Besides, routine detection and reporting of ESBL phenotypes for clinical isolates have not been recommended after following new interpretive breakpoints. More studies are needed to investigate the impacts of these changes on therapeutic strategies and epidemiological surveillance. In addition, pathogens carrying New Delhi metallo-β-lactamases (NDMs), K. pneumoniae carbapenemases (KPCs), and other carbapenemases show extended resistance to currently available antibiotics and rapid transfer between species and countries. Although some of these pathogens are still susceptible to tigecycline and colistin, rates of resistance to these two agents are rising.

SUMMARY

Abdominal sepsis due to multidrug-resistant bacteria, especially ESBL producers, and international and interspecies spreading of metallo-β-lactamase raise key therapeutic problems.

Neutropenic enterocolitis, a growing concern in the era of widespread use of aggressive chemotherapy

Neutropenic enterocolitis (NEC) is a life-threatening disease with substantial morbidity and mortality, seen primarily in patients with hematologic malignancies. The frequency of NEC has increased with the widespread use of chemotherapeutic agents such as the taxanes, which cause severe gastrointestinal mucositis. Neutropenic patients with fever and abdominal symptoms (cramping, pain, distention, diarrhea, GI bleeding), should undergo evaluation of the abdomen for bowel wall thickening of >4 mm, the hallmark of NEC. Clostridium difficile infection should be ruled out, as well as other etiologies such as graft-versus-host disease. Complications include bacteremia, which is often polymicrobial, hemorrhage, and bowel wall perforation/abscess formation. Management includes bowel rest, correction of cytopathies and coagulopathies, and broad spectrum antibiotics and antifungal agents. Surgical intervention may be necessary to manage complications such as hemorrhage and perforation and should be delayed, if possible, until recovery from neutropenia.

Nurses' perceptions of standardised assessment and prevention of complications in an ICU

AIMS AND OBJECTIVES

To describe nurses' perceptions of evidence-based recommendations to prevent complications in a Malaysian intensive care unit.

BACKGROUND

Ventilator-associated pneumonia, catheter-related blood stream infection and pressure ulcer are three frequent adverse events in the intensive care unit. Implementing evidenced-based practice is critical in prevention of these complications.

DESIGN

A qualitative focus group study.

METHODS

Focus groups were conducted with nurses in the intensive care unit of a regional hospital in Malaysia following evidence-based interventions. Focus group transcripts were analysed using the method of thematic analyses.

RESULTS

Thirty-four nurses participated in eight focus groups. The main themes derived from the interviews: (1) nurses' knowledge impacts on the change process; (2) initial resistance, ambivalence and movement to acceptance; and (3) hierarchical organisational structure can hinder the change process.

CONCLUSION

Enhancing nurses' knowledge and attitudes of evidence-based practice, providing them with tools to monitor their clinical practice, and empowering them to change practice are likely to be important in influencing clinical outcomes. Increasing the emphasis on evidence-based practice in nursing curricula and engaging in cultural change processes in the workplace are necessary to improve clinical outcomes.

RELEVANCE TO CLINICAL PRACTICE

These findings provide valuable information for implementing clinical practice improvement interventions.

Nationwide surveillance of antimicrobial susceptibility patterns of pathogens isolated from surgical site infections (SSI) in Japan

To investigate the trends of antimicrobial resistance in pathogens isolated from surgical site infections (SSI), a Japanese surveillance committee conducted the first nationwide survey. Seven main organisms were collected from SSI at 27 medical centers in 2010 and were shipped to a central laboratory for antimicrobial susceptibility testing. A total of 702 isolates from 586 patients with SSI were included. Staphylococcus aureus (20.4 %) and Enterococcus faecalis (19.5 %) were the most common isolates, followed by Pseudomonas aeruginosa (15.4 %) and Bacteroides fragilis group (15.4 %). Methicillin-resistant S. aureus among S. aureus was 72.0 %. Vancomycin MIC 2 μg/ml strains accounted for 9.7 %. In Escherichia coli, 11 of 95 strains produced extended-spectrum β-lactamase (Klebsiella pneumoniae, 0/53 strains). Of E. coli strains, 8.4 % were resistant to ceftazidime (CAZ) and 26.3 % to ciprofloxacin (CPFX). No P. aeruginosa strains produced metallo-β-lactamase. In P. aeruginosa, the resistance rates were 7.4 % to tazobactam/piperacillin (TAZ/PIPC), 10.2 % to imipenem (IPM), 2.8 % to meropenem, cefepime, and CPFX, and 0 % to gentamicin. In the B. fragilis group, the rates were 28.6 % to clindamycin, 5.7 % to cefmetazole, 2.9 % to TAZ/PIPC and IPM, and 0 % to metronidazole (Bacteroides thetaiotaomicron; 59.1, 36.4, 0, 0, 0 %). MIC₉₀ of P. aeruginosa isolated 15 days or later after surgery rose in TAZ/PIPC, CAZ, IPM, and CPFX. In patients with American Society of Anesthesiologists (ASA) score ≥3, the resistance rates of P. aeruginosa to TAZ/PIPC and CAZ were higher than in patients with ASA ≤2. The data obtained in this study revealed the trend of the spread of resistance among common species that cause SSI. Timing of isolation from surgery and the patient's physical status affected the selection of resistant organisms.

Antimicrobial susceptibility profiles of Gram-negative bacilli isolated from patients with hepatobiliary infections in Taiwan: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2006-2010

We investigated the trends in antimicrobial resistance among species of Gram-negative bacilli isolated from patients with hepatobiliary tract infections in Taiwan during the period 2006-2010 as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART). During the study period, 1032 isolates of Gram-negative bacilli that had been collected from patients with hepatobiliary infections were tested for susceptibility to 12 antimicrobial agents in accordance with the Clinical and Laboratory Standards Institute guidelines. Enterobacteriaceae accounted for the majority (n = 874, 84.7%) of isolates and Escherichia coli was the most common pathogen (n = 323, 31.3%). There were significantly more E. coli (P = 0.001) and Proteus mirabilis (P = 0.031) isolates collected from patients who had been hospitalized for less than 48 h and significantly more Serratia marcescens (P = 0.035) and Pseudomonas aeruginosa (P = 0.008) isolates collected from patients who had been hospitalized for 48 h or longer. The prevalence of extended-spectrum β-lactamase (ESBL)-producing pathogens was low. The decline in susceptibility rates with time was remarkable for ceftazidime (P = 0.036), ciprofloxacin (P = 0.029), and levofloxacin (P = 0.018). The most effective antibiotics, i.e., those that were active against more than 90% of Enterobacteriaceae, were amikacin, cefepime, imipenem, ertapenem, and piperacillin-tazobactam. Susceptibility of P. aeruginosa to anti-pseudomonal agents was greater than 80%. In this study, we found an overall increase in resistance to antimicrobial agents among Gram-negative bacilli isolated from patients with hepatobiliary tract infections in Taiwan. Surveillance of antimicrobial susceptibility and updates of treatment guidelines are recommended to help achieve optimal therapy for patients with hepatobiliary infections.

Treatment of necrotizing enterocolitis: an American Pediatric Surgical Association Outcomes and Clinical Trials Committee systematic review

OBJECTIVE

The optimal treatment of necrotizing enterocolitis (NEC) is a common challenge for pediatric surgeons. Although many studies have evaluated prevention and medical therapy for NEC, few guidelines for surgical care exist. The aim of this systematic review is to review and evaluate the currently available evidence for the surgical care of patients with NEC.

METHODS

Data were compiled from a search of PubMed, OVID, the Cochrane Library database, and Web of Science from January 1985 until December 2011. Publications were screened, and their references were hand-searched to identify additional studies. Clinicaltrials.gov was also searched to identify ongoing or unpublished trials. The American Pediatric Surgical Association Outcomes and Clinical Trials Committee proposed six questions deemed pertinent to the surgical treatment of NEC. Recent Cochrane Reviews examined three of these topics; a literature review was performed to address the additional three specific questions.

RESULTS

The Cochrane Reviews support the use of prophylactic probiotics in preterm infants less than 2500 grams to reduce the incidence of NEC, as well as the use of human breast milk rather than formula when possible. There is no clear evidence to support delayed initiation or slow advancement of feeds. For surgical treatment of NEC with perforation, there is no clear support of peritoneal drainage versus laparotomy. Similarly, there is a lack of evidence comparing enterostomy versus primary anastomosis after resection at laparotomy. There are little data to determine the length of treatment with antibiotics to prevent recurrence of NEC.

CONCLUSION

Based on available evidence, probiotics are advised to decrease the incidence of NEC, and human milk should be used when possible. The other reviewed questions are clinically relevant, but there is a lack of evidence-based data to support definitive recommendations. These areas of NEC treatment would benefit from future investigation.

Choosing optimal antimicrobial therapies

Life-threatening infectious disease emergencies require immediate, aggressive parenteral administration of antimicrobial agents to ensure high bactericidal concentrations of drug at the site of infection. Usually initial treatment is empiric until culture results and antimicrobial sensitivities are reported. This approach necessitates the use of broad-spectrum bactericidal agents that will eradicate the presumed infecting organism(s), which potentially could be multidrug resistant. For infections potentially attributable to gram-positive bacteria, vancomycin is commonly used because it will be effective for highly resistant strains such as MRSA and multidrug-resistant S pneumoniae. For gram-negative infections, broad-spectrum β-lactams, such as ceftriaxone, piperacillin-tazobactam, and the carbapenems, are commonly chosen. Excellent alternatives include the fluoroquinolone antibiotics. For nosocomial infections whereby P aeruginosa and other highly resistant organisms may be the cause, antipseudomonal β-lactams such as cefepime, ceftazidime, piperacillin-tazobactam, or doripenem may be used as well as the fluoroquinolone, ciprofloxacin. For anaerobic infections, it is usually necessary to add either metronidazole or clindamycin. Once an infection is under control and the culture and sensitivity results are reported, it is important to switch to the most narrow-spectrum agent possible. Taking this action will decrease the potential for adverse drug effects and the risk of development of antibiotic-induced resistance.

Infectious disease emergencies: frontline clinical pearls

This article reviews various infectious disease emergencies from an internist's perspective. Key epidemiologic, diagnostic, and therapeutic points are reviewed with an emphasis on timely and appropriate initial management. The content serves to highlight essential points that are discussed in subsequent articles in this issue and to elucidate pearls that may facilitate timely and appropriate management.

Bacterial studies of complicated appendicitis over a 20-year period and their impact on empirical antibiotic treatment

BACKGROUND

Multiresistant bacterial strains tend to develop, especially enterobacteriacae, in intraabdominal infections. The aim of this study was to characterize the evolution of the bacterial biota in complicated appendicitis in children over the past 20 years and their acquired resistance rates to antibiotics.

MATERIALS AND METHODS

All pediatric patients admitted in the emergency unit for complicated appendicitis were retrospectively reviewed during 3 periods: 1989 to 1991, 1999 to 2000, and 2009 to 2010. Results of peritoneal swabs were analyzed regarding bacterial species and resistance to antibiotics. Statistical significance was set at P < .05.

RESULTS

Thirty-four, 48, and 85 patients from the 3 periods, respectively, were included, with 1 to 6 bacterial strains found in each peritoneal sample. During the first period, 80% of the biota was composed of enterobacteriacae and anaerobes and then decreased to 65%, whereas streptococci levels increased from 0 to 22%. Pansusceptibility rates remained stable (17%, 16.8%, and 15.6% for the 3 periods, respectively). Piperacillin, vancomycin, ticarcillin-clavulanic acid, and fluoroquinolones were associated with increased resistance rates, unlike antibiotic associations currently used as postoperative treatments.

CONCLUSION

No significant increase in resistance rates of bacteriacae in complicated appendicitis in children was found over the last 20 years. Empirical antibiotherapy protocols currently recommended remain efficient on this particular biota.

Moxifloxacin safety: an analysis of 14 years of clinical data

Background

Moxifloxacin, a fluoroquinolone antibiotic, is used for the treatment of respiratory tract, pelvic inflammatory disease, skin, and intra-abdominal infections. Its safety profile is considered favorable in most reviews but has been challenged with respect to rare but potentially fatal toxicities (e.g. hepatic, cardiac, or skin reactions).

Objective

To analyze and compare the safety profile of moxifloxacin versus comparators in the entire clinical database of the manufacturer.

Setting

Data on the valid-for-safety population from phase II–IV actively controlled studies (performed between 1996 and 2010) were analyzed. Studies were either double blind (n = 22 369) or open label (n = 7635) and included patients with indications that have been approved in at least one country [acute bacterial sinusitis, acute exacerbation of chronic bronchitis, community-acquired pneumonia, uncomplicated pelvic inflammatory disease, complicated and uncomplicated skin and skin structure infections, and complicated intra-abdominal infections] (n = 27 824) and patients with other indications (n = 2180), using the recommended daily dose (400 mg) and route of administration (oral, intravenous/oral, intravenous only). The analysis included patients at risk (age ≥65 years, diabetes mellitus, renal impairment, hepatic impairment, cardiac disorders, or body mass index <18 kg/m²). Patients with known contraindications were excluded from enrollment by study protocol design, but any patient having entered a study, even if inappropriately, was included in the analysis.

Main Outcome Measure

Crude incidences and relative risk estimates (Mantel-Haenszel analysis) of patients with any adverse event (AE), adverse drug reaction (ADR), serious AE (SAE), serious ADR (SADR), treatment discontinuation due to an AE or ADR, and fatal outcomes related to an AE or ADR.

Results

Overall incidence rates of AEs were globally similar in the moxifloxacin and comparator groups. By filtering the data for differences in disfavor of moxifloxacin (i) at ≥2.5% for events with an incidence ≥2.5% or at ≥2-fold for events with an incidence <2.5% in one or both groups and (ii) affecting ≥10 patients in either group, we observed slightly more (i) AEs in double-blind intravenous-only and open-label oral studies, (ii) SAEs in double-blind intravenous-only studies, (iii) ADRs and SADRs in open-label oral studies, (iv) SADRs in open-label intravenous/oral studies, and (v) premature discontinuation due to AEs in open-label intravenous-only studies. The actual numbers of SADRs (in all studies) were small, with clinically relevant differences noted only in intravenous/oral studies and mainly driven by ‘gastrointestinal disorders’ (15 versus 7 patients) and ‘changes observed during investigations’ (23 versus 7 patients [asymptomatic QT prolongation: 11 versus 4 patients in double-blind studies]). Analysis by comparator (including another fluoroquinolone) did not reveal medically relevant differences, even in patients at risk. Incidence rates of hepatic disorders, tendon disorders, clinical surrogates of QT prolongation, serious cutaneous reactions, and Clostridium difficile-associated diarrhea were similar with moxifloxacin and comparators.

Conclusion

The safety of moxifloxacin is essentially comparable to that of standard therapies for patients receiving the currently registered dosage and for whom contraindications and precautions of use (as in the product label) are taken into account.

Combination therapy for treatment of infections with gram-negative bacteria

Combination antibiotic therapy for invasive infections with Gram-negative bacteria is employed in many health care facilities, especially for certain subgroups of patients, including those with neutropenia, those with infections caused by Pseudomonas aeruginosa, those with ventilator-associated pneumonia, and the severely ill. An argument can be made for empiric combination therapy, as we are witnessing a rise in infections caused by multidrug-resistant Gram-negative organisms. The wisdom of continued combination therapy after an organism is isolated and antimicrobial susceptibility data are known, however, is more controversial. The available evidence suggests that the greatest benefit of combination antibiotic therapy stems from the increased likelihood of choosing an effective agent during empiric therapy, rather than exploitation of in vitro synergy or the prevention of resistance during definitive treatment. In this review, we summarize the available data comparing monotherapy versus combination antimicrobial therapy for the treatment of infections with Gram-negative bacteria.

Global fluoroquinolone resistance epidemiology and implictions for clinical use

This paper on the fluoroquinolone resistance epidemiology stratifies the data according to the different prescription patterns by either primary or tertiary caregivers and by indication. Global surveillance studies demonstrate that fluoroquinolone resistance rates increased in the past years in almost all bacterial species except S. pneumoniae and H. influenzae, causing community-acquired respiratory tract infections. However, 10 to 30% of these isolates harbored first-step mutations conferring low level fluoroquinolone resistance. Fluoroquinolone resistance increased in Enterobacteriaceae causing community acquired or healthcare associated urinary tract infections and intraabdominal infections, exceeding 50% in some parts of the world, particularly in Asia. One to two-thirds of Enterobacteriaceae producing extended spectrum β-lactamases were fluoroquinolone resistant too. Furthermore, fluoroquinolones select for methicillin resistance in Staphylococci. Neisseria gonorrhoeae acquired fluoroquinolone resistance rapidly; actual resistance rates are highly variable and can be as high as almost 100%, particularly in Asia, whereas resistance rates in Europe and North America range from <10% in rural areas to >30% in established sexual networks. In general, the continued increase in fluoroquinolone resistance affects patient management and necessitates changes in some guidelines, for example, treatment of urinary tract, intra-abdominal, skin and skin structure infections, and traveller's diarrhea, or even precludes the use in indications like sexually transmitted diseases and enteric fever.

Therapy of 1,025 severely ill patients with complicated infections in a German multicenter study: safety profile and efficacy of tigecycline in different treatment modalities

This large prospective non-interventional study investigated the effects of tigecycline either as single agent or in combination with other antimicrobial agents in 1,025 patients treated in clinical routine at German hospitals. Sixty-five percent of the patients had APACHE II scores > 15, indicating high overall disease severity. Complicated intra-abdominal infections (cIAI) or complicated skin and skin tissue infections (cSSTI) were the most common indications, with Staphylococcus aureus, Enterococcus faecium and Escherichia coli being the most frequently isolated pathogens. Clinical success was reported at the end of tigecycline therapy in 74.2% of the total population, in 75.4% of the cIAI and in 82.2% of the cSSTI patients. The subpopulation (28.0% of the patients) infected with multidrug-resistant pathogens (methicillin-resistant S. aureus, extended-spectrum β-lactamase producers and vancomycin-resistant enterococci) were treated with similar success rates as the overall population. Tigecycline was generally well tolerated. Drug-related adverse events (AEs) were reported in 7.7% of the total population; 2.5% had serious AEs mostly attributable to inefficacy of therapy or deterioration of the disease. Mortality rates were consistent with the types of infection and severity of illness. There was no indication of excessive mortality associated with tigecycline as had been suggested in previously performed meta-analyses. In this large non-interventional study performed in the clinical routine setting, tigecycline achieved favorable clinical success rates in a patient population with high severity of illness and a high prevalence of multidrug-resistant pathogens and showed a good safety and tolerability profile.

White paper: recommendations on the conduct of superiority and organism-specific clinical trials of antibacterial agents for the treatment of infections caused by drug-resistant bacterial pathogens

There is a critical need for new pathways to develop antibacterial agents to treat life-threatening infections caused by highly resistant bacteria. Traditionally, antibacterial agents have been studied in noninferiority clinical trials that focus on one site of infection (eg, pneumonia, intra-abdominal infection). Conduct of superiority trials for infections caused by highly antibiotic-resistant bacteria represents a new, and as yet, untested paradigm for antibacterial drug development. We sought to define feasible trial designs of antibacterial agents that could enable conduct of superiority and organism-specific clinical trials. These recommendations are the results of several years of active dialogue among the white paper's drafters as well as external collaborators and regulatory officials. Our goal is to facilitate conduct of new types of antibacterial clinical trials to enable development and ultimately approval of critically needed new antibacterial agents.

The preanalytical optimization of blood cultures: a review and the clinical importance of benchmarking in 5 Belgian hospitals

Bloodstream infections remain a major challenge in medicine. Optimal detection of pathogens is only possible if the quality of preanalytical factors is thoroughly controlled. Since the laboratory is responsible for this preanalytical phase, the quality control of critical factors should be integrated in its quality control program. The numerous recommendations regarding blood culture collection contain controversies. Only an unambiguous guideline permits standardization and interlaboratory quality control. We present an evidence-based concise guideline of critical preanalytical determinants for blood culture collection and summarize key performance indicators with their concomitant target values. In an attempt to benchmark, we compared the true-positive rate, contamination rate, and collected blood volume of blood culture bottles in 5 Belgian hospital laboratories. The true-positive blood culture rate fell within previously defined acceptation criteria by Baron et al. (2005) in all 5 hospitals, whereas the contamination rate exceeded the target value in 4 locations. Most unexpected, in each of the 5 laboratories, more than one third of the blood culture bottles were incorrectly filled, irrespective of the manufacturer of the blood culture vials. As a consequence of this shortcoming, one manufacturer recently developed an automatic blood volume monitoring system. In conclusion, clear recommendations for standardized blood culture collection combined with quality control of critical factors of the preanalytical phase are essential for diagnostic blood culture improvement.

Safety and effectiveness of meropenem in infants with suspected or complicated intra-abdominal infections

BACKGROUND

Intra-abdominal infections are common in young infants and lead to significant morbidity and mortality. Meropenem is a broad-spectrum antimicrobial with excellent activity against pathogens associated with intra-abdominal infections. The purpose of this study was to determine the safety and effectiveness of meropenem in young infants with suspected or complicated intra-abdominal infections.

METHODS

Preterm and term infants <91 days of age with suspected or confirmed intra-abdominal infections hospitalized in 24 neonatal intensive care units were studied in an open-label, multiple-dose study. Adverse events and serious adverse events were collected through 3 and 30 days following the last meropenem dose, respectively. Effectiveness was assessed by 3 criteria: death, bacterial cultures, and presumptive clinical cure score.

RESULTS

Of 200 subjects enrolled in the study, 99 (50%) experienced an adverse event, and 34 (17%) had serious adverse events; no adverse events were probably or definitely related to meropenem. The most commonly reported adverse events were sepsis (6%), seizures (5%), elevated conjugated bilirubin (5%), and hypokalemia (5%). Only 2 of the serious adverse events were determined to be possibly related to meropenem (isolated ileal perforation and an episode of fungal sepsis). Effectiveness was evaluable in 192 (96%) subjects, and overall treatment success was 84%.

CONCLUSIONS

Meropenem was well tolerated in this cohort of critically ill infants, and the majority of infants treated with meropenem met the definition of therapeutic success.

CLINICAL TRIALS REGISTRATION

NCT00621192.

Considerations of antibiotic therapy duration in community- and hospital-acquired bacterial infections

Despite the large number of suggestions available in the literature, the optimal duration of antibiotic treatment remains an individual decision mainly based on clinical criteria. Shorter but equally effective regimens would reduce the side effect rates, including both antibiotic resistance and drug expenses. Although several prospective, randomized trials and meta-analyses with the aim of comparing a standard duration with a shorter one for most bacterial infections have been published, to date most current recommendations carry little weight, as they are based on expert opinions or practical experience. This review will briefly touch upon the clinical evidence of short-course versus long-course antibiotic therapy for the most common community- and hospital-acquired bacterial infections.

Clinical and laboratory variables identifying bacterial infection and bacteraemia in the emergency department

BACKGROUND

While early antimicrobial treatment is of critical importance to patients with severe infections, excessive use of antibiotics has caused escalating bacterial resistance. Better diagnostic tools are needed to secure antibiotic stewardship.

METHODS

The diagnostic value of clinical and laboratory variables in predicting infections that require antibiotic treatment was evaluated in a prospective observational study of 404 adult patients admitted from the emergency department (ED) with suspected severe infections. We also investigated the association of these variables with bacteraemia and severe sepsis.

RESULTS

In a univariate analysis, increased levels of C-reactive protein (CRP), procalcitonin (PCT), interleukin 6 (IL-6), lipopolysaccharide binding protein (LBP), white blood cell count (WBC), neutrophils, respiratory rate (RR) (p ≤ 0.001), and a decreased haemoglobin (Hb) level (p = 0.005) were associated with an indicated demand for antibiotics (n = 286). In a multivariate analysis, only WBC, Hb, RR, and CRP remained independent predictors. When compared to the clinician's ability to make accurate antibiotic decisions, all variables tested had inferior diagnostic accuracy except CRP. Increased levels of PCT, IL-6, LBP, CRP, bilirubin, and RR were significantly associated with bacteraemia (n = 68) (p ≤ 0.001). Of these, PCT and IL-6 were also associated with severe sepsis (n = 156) (p < 0.001). In a multivariate analysis, CRP, RR, PCT, and bilirubin remained associated with bacteraemia.

CONCLUSIONS

Special attention should be directed to CRP, WBC, RR, and Hb when selecting patients for antibiotic treatment in the emergency department. PCT, IL-6, and LBP did not provide additional guidance on antibiotic decisions and better tests are required in order to improve antibiotic stewardship.

Essentials for selecting antimicrobial therapy for intra-abdominal infections

Intra-abdominal infection (IAI) is a complex disease entity in which different aspects must be balanced in order to select the proper antimicrobial regimen and determine duration of therapy. A current classification indicates different faces of peritonitis. Primary peritonitis implies an intact gastrointestinal tract without overt barrier disruption. Secondary peritonitis refers to localized or diffuse peritoneal inflammation and abscess formation due to disruption of the anatomical barrier. Tertiary peritonitis includes cases that cannot be solved by a single or even sequential surgical intervention, often in combination with sequential courses of antimicrobial therapy. The most frequently used classification distinguishes ‘uncomplicated’ and ‘complicated’ IAI. In uncomplicated IAI, the infectious process is contained within a single organ, without anatomical disruption. In complicated IAI, disease is extended, with either localized or generalized peritonitis. However, there exists more than a single dimension of complexity in IAI, including severity of disease expression through systemic inflammation. As the currently used classifications of IAI often incite confusion by mixing elements of anatomical barrier disruption, severity of disease expression and (the likelihood of) resistance involvement, we propose an alternative for the current widely accepted classification. We suggest abandoning the terms ‘uncomplicated’ and ‘complicated’ IAI, as they merely confuse the issue. Furthermore, the term ‘tertiary peritonitis’ should likewise be discarded, as this simply refers to treatment failure of secondary peritonitis resulting in a state of persistent infection and/or inflammation. Hence, anatomical disruption and disease severity should be separated into different phenotypes for the same disease in combination with either presence or absence of risk factors for involvement of pathogens that are not routinely covered in first-line antimicrobial regimens (Pseudomonas aeruginosa, enterococci, Candida species and resistant pathogens). Generally, these risk factors can be brought back to recent exposure to antimicrobial agents and substantial length of stay in healthcare settings (5–7 days). As such, we developed a grid based on the different components of the classification: (i) anatomical disruption; (ii) severity of disease expression; and (iii) either community-acquired/early-onset healthcare-associated origin or healthcare-associated origin and/or recent antimicrobial exposure. The grid allows physicians to define the index case of IAI in a more unequivocal way and to select the most convenient empirical antimicrobial regimens. The grid advises on the necessity of covering nosocomial Gram-negative bacteria (including P. aeruginosa), enterococci and yeasts. The basis of antimicrobial therapy for IAI is that both Gram-negative and anaerobic bacteria should always be covered.

In recent years, some newer agents such as doripenem, moxifloxacin and tigecycline have been added to the antimicrobial armamentarium for IAI. For patients in whom the source can be adequately controlled, antimicrobial therapy should be restricted to a short course (e.g. 3–7 days in peritonitis).

In vitro activity of tigecycline and comparators against organisms associated with intra-abdominal infections collected as part of TEST (2004-2009)

As part of the Tigecycline Evaluation and Surveillance Trial (TEST), bacterial isolates were collected consecutively from centers globally between 2004 and 2009. MICs were determined locally using Clinical and Laboratory Standards Institute broth microdilution methodology. A total of 3114 anaerobic and 99,256 aerobic isolates were included in this study. The most active agents against Gram-negative anaerobes were metronidazole and meropenem (resistance ranges 0.0-0.5% and 0.0-0.9%, respectively); piperacillin-tazobactam was also active (resistance range 0.5-9.4%). Among Gram-positive anaerobes, resistance rates were lowest for meropenem, piperacillin-tazobactam, and metronidazole (ranges 0.0-0.5%, 0.0-1.8%, and 0.0-3.2% respectively). Tigecycline MIC(90) values for anaerobes ranged from 0.12 to 2 μg/mL. The most active antimicrobial agent against Gram-negative aerobes (excluding Pseudomonas aeruginosa) was tigecycline, with resistance ranging from <0.01% to 1.4%. Resistance was also low for imipenem (0.3-9.4%) and meropenem (0.7-15.1%). Extended-spectrum beta-lactamases were produced by 12.2% and 19.7% of E. coli and K. pneumoniae isolates, respectively.

Detection of Staphylococcus aureus delta-toxin production by whole-cell MALDI-TOF mass spectrometry

The aim of the present study was to detect the Staphylococcus aureus delta-toxin using Whole-Cell (WC) Matrix Assisted Laser Desorption Ionization-Time-of-Flight (MALDI-TOF) mass spectrometry (MS), correlate delta-toxin expression with accessory gene regulator (agr) status, and assess the prevalence of agr deficiency in clinical isolates with and without resistance to methicillin and glycopeptides. The position of the delta-toxin peak in the mass spectrum was identified using purified delta-toxin and isogenic wild type and mutant strains for agr-rnaIII, which encodes delta-toxin. Correlation between delta-toxin production and agr RNAIII expression was assessed by northern blotting. A series of 168 consecutive clinical isolates and 23 unrelated glycopeptide-intermediate S. aureus strains (GISA/heterogeneous GISA) were then tested by WC-MALDI-TOF MS. The delta-toxin peak was detected at 3005±5 Thomson, as expected for the naturally formylated delta toxin, or at 3035±5 Thomson for its G10S variant. Multivariate analysis showed that chronicity of S. aureus infection and glycopeptide resistance were significantly associated with delta-toxin deficiency (p = 0.048; CI 95%: 1.01-10.24; p = 0.023; CI 95%: 1.20-12.76, respectively). In conclusion, the S. aureus delta-toxin was identified in the WC-MALDI-TOF MS spectrum generated during routine identification procedures. Consequently, agr status can potentially predict infectious complications and rationalise application of novel virulence factor-based therapies.

Ruptured Splenic Abscess following Percutaneous Transluminal Angioplasty in a 40-Year-Old Man

The incidence of splenic abscesses is currently 0.14–0.7% with a reported mortality of 0–47%. The diagnosis of splenic abscess which has ruptured into the abdomen is often overlooked because of its rarity and its misleading clinical presentations. Percutaneous coronary interventions (PCIs) and coronary stenting procedures increased from 184,000 to 885,000 (from 335 to 1,550) and from 3,000 to 770,000 (from 5 to 1,350 per one million inhabitants), respectively. A 40-year-old Asian male presented to our emergency department with upper abdominal pain 5 days after a percutaneous transluminal coronary angioplasty. Clinical examination raised the possibilities of acute pancreatitis and intraabdominal sepsis. An initial ultrasound of the abdomen and blood tests were negative. A computed tomography scan of the abdomen revealed a splenic abscess that had ruptured into the abdomen. Pus culture revealed a multidrug-resistant strain of Klebsiella pneumoniae that was sensitive to meropenem. The patient recovered quickly after open surgical drainage and antibiotic therapy. As this is the second case of splenic abscess and the first case report of a ruptured splenic abscess following a PCI, it will be rational to administer a short course of antibiotic prophylaxis for high-risk immunocompromised patients who are undergoing percutaneous transluminal coronary intervention.

Does the piperacillin minimum inhibitory concentration for Pseudomonas aeruginosa influence clinical outcomes of children with pseudomonal bacteremia?

BACKGROUND

The Clinical and Laboratory Standards Institute (CLSI) recently elected to adjust the previous piperacillin susceptibility breakpoint of ≤64 µg/mL against Pseudomonas aeruginosa to ≤16 µg/mL, based largely on pharmacokinetic-pharmacodynamic (PK-PD) modeling studies. Data on whether PK-PD modeling correlates with clinical outcomes in children are needed before resorting to broader classes of antibiotics to treat P. aeruginosa.

METHODS

We performed a retrospective cohort study of children with P. aeruginosa bacteremia between 2001 and 2010 who were prescribed piperacillin. Baseline characteristics and clinical outcomes of children with piperacillin minimum inhibitory concentrations (MICs) of ≤16 µg/mL and of 32-64 µg/mL were compared. The primary outcome was 30-day mortality.

RESULTS

There were 170 children with P. aeruginosa bacteremia receiving piperacillin therapy who met inclusion criteria. One hundred twenty-four (72%) children had piperacillin MICs of ≤16 µg/mL and 46 (28%) children had piperacillin MICs of 32-64 µg/mL. There was no significant difference in baseline characteristics between the 2 groups. Thirty-day mortality was 9% and 24% in children with a piperacillin MIC of ≤16 µg/mL and of 32-64 µg/mL, respectively. Using multivariable logistic regression, children with elevated MICs had increased odds of mortality compared with children with lower MICs (odds ratio, 3.21; 95% confidence interval, 1.26-8.16).

CONCLUSIONS

Our finding that elevated piperacillin MICs are associated with higher mortality in children supports the recent CLSI recommendation to lower the breakpoint of piperacillin against P. aeruginosa to ≤16 µg/mL. Alternate therapeutic choices should be considered when piperacillin MICs against P. aeruginosa are ≥32 µg/mL.

Excess deaths associated with tigecycline after approval based on noninferiority trials

BACKGROUND

On the basis of noninferiority trials, tigecycline received Food and Drug Administration (FDA) approval in 2005. In 2010, the FDA warned in a safety communication that tigecycline was associated with an increased risk of death.

METHODS

PubMed, EMBASE, Scopus, and ClinicalTrials.gov were searched using the terms "tigecycline" and "randomized controlled trial (RCT)" through April 2011. Excess deaths and noncure rates for both approved and nonapproved indications were examined using meta-analysis.

RESULTS

Ten published and 3 unpublished studies met inclusion criteria (N = 7434). No significant heterogeneity was seen for mortality (I(2 )= 0%; P = .99) or noncure rates (I(2 )= 25%; P = .19). Across randomized controlled trials, tigecycline was associated with increased mortality (risk difference [RD], 0.7%; 95% confidence interval [CI], 0.1%-1.2%; P = .01) and noncure rates (RD, 2.9%; 95% CI, 0.6%-5.2%; P = .01). Effects were not isolated to type of infection or comparator antibiotic regimen, and the impact on survival remained significant when limited to trials of approved indications (I(2 )= 0%; RD, 0.6%; P = .04). A pooled analysis of the 5 trials completed by early 2005 before tigecycline was approved would have demonstrated a similar harmful effect of tigecycline on survival (I(2 )= 0%; RD, 0.7%; P = .06).

CONCLUSIONS

Pooling noninferiority studies to examine survival may help ensure the safety and efficacy of new antibiotics. The association of tigecycline with excess deaths and noncure includes indications for which it is approved and marketed. Tigecycline cannot be relied on in serious infections.

Resistance surveillance studies: a multifaceted problem--the fluoroquinolone example

INTRODUCTION

This review summarizes data on the fluoroquinolone resistance epidemiology published in the previous 5 years.

MATERIALS AND METHODS

The data reviewed are stratified according to the different prescription patterns by either primary- or tertiary-care givers and by indication. Global surveillance studies demonstrate that fluoroquinolone- resistance rates increased in the past several years in almost all bacterial species except Staphylococcus pneumoniae and Haemophilus influenzae causing community-acquired respiratory tract infections (CARTIs), as well as Enterobacteriaceae causing community-acquired urinary tract infections. Geographically and quantitatively varying fluoroquinolone resistance rates were recorded among Gram-positive and Gram-negative pathogens causing healthcare-associated respiratory tract infections. One- to two-thirds of Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs) were fluoroquinolone resistant too, thus, limiting the fluoroquinolone use in the treatment of community- as well as healthcare-acquired urinary tract and intra-abdominal infections. The remaining ESBL-producing or plasmid-mediated quinolone resistance mechanisms harboring Enterobacteriaceae were low-level quinolone resistant. Furthermore, 10-30 % of H. influenzae and S. pneumoniae causing CARTIs harbored first-step quinolone resistance determining region (QRDR) mutations. These mutants pass susceptibility testing unnoticed and are primed to acquire high-level fluoroquinolone resistance rapidly, thus, putting the patient at risk. The continued increase in fluoroquinolone resistance affects patient management and necessitates changes in some current guidelines for the treatment of intra-abdominal infections or even precludes the use of fluoroquinolones in certain indications like gonorrhea and pelvic inflammatory diseases in those geographic areas in which fluoroquinolone resistance rates and/or ESBL production is high. Fluoroquinolone resistance has been selected among the commensal flora colonizing the gut, nose, oropharynx, and skin, so that horizontal gene transfer between the commensal flora and the offending pathogen as well as inter- and intraspecies recombinations contribute to the emergence and spread of fluoroquinolone resistance among pathogenic streptococci. Although interspecies recombinations are not yet the major cause for the emergence of fluoroquinolone resistance, its existence indicates that a large reservoir of fluoroquinolone resistance exists. Thus, a scenario resembling that of a worldwide spread of β-lactam resistance in pneumococci is conceivable. However, many resistance surveillance studies suffer from inaccuracies like the sampling of a selected patient population, restricted geographical sampling, and undefined requirements of the user, so that the results are biased. The number of national centers is most often limited with one to two participating laboratories, so that such studies are point prevalence but not surveillance studies. Selected samples are analyzed predominantly as either hospitalized patients or patients at risk or those in whom therapy failed are sampled; however, fluoroquinolones are most frequently prescribed by the general practitioner. Selected sampling results in a significant over-estimation of fluoroquinolone resistance in outpatients. Furthermore, the requirements of the users are often not met; the prescribing physician, the microbiologist, the infection control specialist, public health and regulatory authorities, and the pharmaceutical industry have diverse interests, which, however, are not addressed by different designs of a surveillance study. Tools should be developed to provide customer-specific datasets.

CONCLUSION

Consequently, most surveillance studies suffer from well recognized but uncorrected biases or inaccuracies. Nevertheless, they provide important information that allows the identification of trends in pathogen incidence and antimicrobial resistance.

[Microbiological diagnosis of intra-abdominal infections]

Intra-abdominal infections represent a large and wide group of diseases which include intra- and retro-peritoneal infections. Some of them could be defined as uncomplicated, where the infectious process is limited to the organ or tissue of origin (appendicitis, diverticulitis, cholecystitis…). Complications occur when the infection spreads to the peritoneum, triggering localised peritonitis and abdominal abscesses. Most intra-abdominal infections are due to perforation or inflammation of the intestinal wall. The microorganisms that cause these infections come from the gastrointestinal flora, and therefore produce polymicrobial infections mixed with a predominance of anaerobic bacteria. Microbiological diagnosis is essential to determine the aetiology and the susceptibility of antimicrobial agents of the microorganism involved, especially in nosocomial infections or in community infections in predisposed patients due to increasing bacterial resistance to antimicrobial agents, multidrug resistance and fungal involvement. Despite the advances in microbiological diagnosis, in the case of intra-abdominal infections it still remains direct, being based on stains and cultures, the most notable progress is the introduction of mass spectrometry (MALDI-TOF) for the rapid identification of the pathogens involved. This review will provide recommendations on the collection, transport and microbiological processing of clinical specimens. Comments on the pathogenesis, clinical and microbiological diagnosis of peritonitis primary, secondary, tertiary and peritonitis (and other infections) associated with peritoneal dialysis, intra-abdominal abscesses (intraperitoneal, retroperitoneal and visceral), biliary tract infections, appendicitis and diverticulitis are also presented.