Effect of inappropriate initial empiric antibiotic therapy on outcome of patients with community-acquired intra-abdominal infections requiring surgery

Healthcare-associated bloodstream infection: A distinct entity? Insights from a large U.S. database*

OBJECTIVE

To gain a better understanding of the epidemiology, microbiology, and outcomes of early-onset, culture-positive, community-acquired, healthcare-associated, and hospital-acquired bloodstream infections.

DESIGN

We analyzed a large U.S. database (Cardinal Health, MediQual, formerly MedisGroups) to identify patients with bacterial or fungal bloodstream isolates from 2002 to 2003.

SETTING

The data set included administrative and clinical variables (physiologic, laboratory, culture, and other clinical) from 59 hospitals. Bloodstream infections were identified in those hospitals collecting clinical and culture data for at least the first 5 days of admission.

PATIENTS

Patients with bloodstream infection within 2 days of admission were classified as having community-acquired bloodstream infection. Those with a prior hospitalization within 30 days, transfer from another facility, ongoing chemotherapy, or long-term hemodialysis were classified as having healthcare-associated bloodstream infection. Bloodstream infections that developed after day 2 of admission were classified as hospital-acquired bloodstream infection. A total of 6,697 patients were identified as having bloodstream infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Healthcare-associated bloodstream infection accounted for more than half (55.3%) of all bloodstream infections. Nearly two thirds (62.3%) of hospitalized patients with bloodstream infection suffered from either hospital-acquired bloodstream infection or healthcare-associated bloodstream infection and had higher morbidity and mortality rates than those with community-acquired bloodstream infection. Of all bloodstream infection pathogens, fungal organisms were associated with the highest crude mortality, longest length of stay in hospital, and greatest total charges. Of all bacterial bloodstream infections, methicillin-resistant Staphylococcus aureus was associated with the highest crude mortality rate (22.5%), the longest mean length of stay (11.1 +/- 10.7 days), and the highest median total charges ($36,109). After we controlled for confounding factors, methicillin-resistant S. aureus was associated with the highest independent mortality risk (odds ratio 2.70; confidence interval 2.03-3.58). S. aureus was the most commonly encountered pathogen in all types of early-onset bacteremia.

CONCLUSIONS

Healthcare-associated bloodstream infection constitutes a distinct entity of bloodstream infection with its unique epidemiology, microbiology, and outcomes. Methicillin-resistant Staphylococcus aureus carries the highest relative mortality risk among all pathogens.

Inappropriate initial treatment of secondary intra-abdominal infections leads to increased risk of clinical failure and costs

AIMS

The objective of this population-based, retrospective cohort study was to investigate the incidence and initial antibiotic treatment of secondary intra-abdominal infections (sIAI) and to assess whether inappropriate initial antibiotic therapy affects patient outcomes.

METHODS

All patients hospitalized for sIAI (1995-1998) were identified in the PHARMO Record Linkage System, a patient-centric database including pharmacy dispensing records from community pharmacies linked to hospitalization records in the Netherlands. Complementary in-hospital antibiotic drug use was obtained from the computerized inpatient pharmacy files. The patient outcomes considered were switch to second-line antibiotic treatment, re-operation, and death. In addition, a composite variable clinical failure was constructed based on the above-mentioned outcomes. Furthermore, the effect of clinical failure on length of hospital stay and costs of hospitalization was assessed. Associations between appropriateness of initial antibiotic treatment and outcomes were estimated using multivariate logistic and linear regression models.

RESULTS

In the source population of 228,000 persons, 175 cases were classified as sIAI (mean age 49.3 +/- 24.5, 50.9% male) resulting in an incidence of 2.3/10,000 person-years [95% confidence interval (CI) 2.0, 2.7]. Initial antibiotic treatment was appropriate for 84% of the cases. The risk of clinical failure was 17.1%. Inappropriate initial antibiotic treatment increased the risk of clinical failure 3.4-fold (95% CI 1.3, 9.1). Length of hospital stay and costs of hospitalization were significantly increased for patients with clinical failure.

CONCLUSIONS

Inappropriate choice of initial antibiotic therapy in sIAI patients leads to more clinical failure resulting in a longer hospital stay and higher costs of hospitalization compared with appropriate initial antibiotic therapy.

Importance of appropriateness of empiric antibiotic therapy on clinical outcomes in intra-abdominal infections

Objectives:The objective of this study is to describe the frequency of inappropriate empirical antibiotic therapy in secondary intra-abdominal infection and to identify the possible relationship between inappropriateness and some clinical outcomes.

Methods:A retrospective descriptive multicenter study was conducted using hospital secondary databases developed at two university hospitals located in northeast Spain. Participants were patients 18 years of age or older who were diagnosed with community-acquired intra-abdominal infections between January 1, 1998, and December 31, 2000, identified through computerized patient records using ICD-9 codes. Appropriateness of empirical treatment was defined according to the recommendations of the literature. The clinical outcome of each patient was classified as one of the following: (i) resolved with initial therapy, (ii) required second-line antibiotics, (iii) required re-operation, or (iv) in-hospital death. The Fisher's exact test or the Chi-squared test for categorical variables and thet-test or Mann–Whitney test for continuous variables were used for comparing groups. Conditional logistic and linear regression analyses were also applied.

Results:Of 376 cases, 51 cases (13.6 percent, 95 percent confidence interval, 10–17 percent) received inappropriate empirical antibiotic therapy according to the scientific literature. Inappropriate initial empirical treatment was significantly associated with the need for a second line of antibiotics (p<.001), although not with re-operation, mortality, or length of hospitalization.

Conclusions:Approximately 14 percent of the patients received inappropriate empirical antibiotic treatment. Worse clinical outcomes consistently were observed in the group of patients receiving inappropriate empirical treatment. The appropriateness of antibiotic treatment for a given infection, in light of the availability of clearly defined clinical guidelines is an easily evaluated aspect of the quality of care.

A multicenter trial of the efficacy and safety of tigecycline versus imipenem/cilastatin in patients with complicated intra-abdominal infections [Study ID Numbers: 3074A1-301-WW; ClinicalTrials.gov Identifier: NCT00081744]

BACKGROUND

Complicated intra-abdominal infections (cIAI) remain challenging to treat because of their polymicrobial etiology including multi-drug resistant bacteria. The efficacy and safety of tigecycline, an expanded broad-spectrum glycylcycline antibiotic, was compared with imipenem/cilastatin (IMI/CIS) in patients with cIAI.

METHODS

A prospective, double-blind, multinational trial was conducted in which patients with cIAI randomly received intravenous (IV) tigecycline (100 mg initial dose, then 50 mg every 12 hours [q12h]) or IV IMI/CIS (500/500 mg q6h or adjusted for renal dysfunction) for 5 to14 days. Clinical response at the test-of-cure (TOC) visit (14-35 days after therapy) for microbiologically evaluable (ME) and microbiological modified intent-to-treat (m-mITT) populations were the co-primary efficacy endpoint populations.

RESULTS

A total of 825 patients received >or= 1 dose of study drug. The primary diagnoses for the ME group were complicated appendicitis (59%), and intestinal (8.8%) and gastric/duodenal perforations (4.6%). For the ME group, clinical cure rates at TOC were 80.6% (199/247) for tigecycline versus 82.4% (210/255) for IMI/CIS (95% CI -8.4, 5.1 for non-inferiority tigecycline versus IMI/CIS). Corresponding clinical cure rates within the m-mITT population were 73.5% (227/309) for tigecycline versus 78.2% (244/312) for IMI/CIS (95% CI -11.0, 2.5). Nausea (31.0% tigecycline, 24.8% IMI/CIS [P = 0.052]), vomiting (25.7% tigecycline, 19.4% IMI/CIS [P = 0.037]), and diarrhea (21.3% tigecycline, 18.9% IMI/CIS [P = 0.435]) were the most frequently reported adverse events.

CONCLUSION

This study demonstrates that tigecycline is as efficacious as imipenem/cilastatin in the treatment of patients with cIAI.