Accuracy of American Thoracic Society/Infectious Diseases Society of America criteria in predicting infection or colonization with multidrug-resistant bacteria at intensive-care unit admission

Using time-series chest radiographs and laboratory data by machine learning for identifying pulmonary infection and colonization of Acinetobacter baumannii

BACKGROUND

Accurately distinguishing between pulmonary infection and colonization in patients with Acinetobacter baumannii is of utmost importance to optimize treatment and prevent antibiotic abuse or inadequate therapy. An efficient automated sorting tool could prompt individualized interventions and enhance overall patient outcomes. This study aims to develop a robust machine learning classification model using a combination of time-series chest radiographs and laboratory data to accurately classify pulmonary status caused by Acinetobacter baumannii.

METHODS

We proposed nested logistic regression models based on different time-series data to automatically classify the pulmonary status of patients with Acinetobacter baumannii. Advanced features were extracted from the time-series data of hospitalized patients, encompassing dynamic pneumonia indicators observed on chest radiographs and laboratory indicator values recorded at three specific time points.

RESULTS

Data of 152 patients with Acinetobacter baumannii cultured from sputum or alveolar lavage fluid were retrospectively analyzed. Our model with multiple time-series data demonstrated a higher performance of AUC (0.850, with a 95% confidence interval of [0.638-0.873]), an accuracy of 0.761, a sensitivity of 0.833. The model, which only incorporated a single time point feature, achieved an AUC of 0.741. The influential model variables included difference in the chest radiograph pneumonia score.

CONCLUSION

Dynamic assessment of time-series chest radiographs and laboratory data using machine learning allowed for accurate classification of colonization and infection with Acinetobacter baumannii. This demonstrates the potential to help clinicians provide individualized treatment through early detection.

Preventing Multidrug-Resistant Bacterial Transmission in the Intensive Care Unit with a Comprehensive Approach: A Policymaking Manual

Patients referred to intensive care units (ICU) commonly contract infections caused by multidrug-resistant (MDR) bacteria, which are typically linked to complications and high mortality. There are numerous independent factors that are associated with the transmission of these pathogens in the ICU. Preventive multilevel measures that target these factors are of great importance in order to break the chain of transmission. In this review, we aim to provide essential guidance for the development of robust prevention strategies, ultimately ensuring the safety and well-being of patients and healthcare workers in the ICU. We discuss the role of ICU personnel in cross-contamination, existing preventative measures, novel technologies, and strategies employed, along with antimicrobial surveillance and stewardship (AMSS) programs, to construct effective and thoroughly described policy recommendations. By adopting a multifaceted approach that combines targeted interventions with broader preventive strategies, healthcare facilities can create a more coherent line of defense against the spread of MDR pathogens. These recommendations are evidence-based, practical, and aligned with the needs and realities of the ICU setting. In conclusion, this comprehensive review offers a blueprint for mitigating the risk of MDR bacterial transmission in the ICU, advocating for an evidence-based, multifaceted approach.

In-hospital mortality and one-year survival of critically ill patients with cancer colonized or not with carbapenem-resistant gram-negative bacteria or vancomycin-resistant enterococci: an observational study

BACKGROUND

Patients with cancer are at risk of multidrug-resistant bacteria colonization, but association of colonization with in-hospital mortality and one-year survival has not been established in critically ill patients with cancer.

METHODS

Using logistic and Cox-regression analyses adjusted for confounders, in adult patients admitted at intensive care unit (ICU) with active cancer, we evaluate the association of colonization by carbapenem-resistant Gram-negative bacteria or vancomycin-resistant enterococci with in-hospital mortality and one-year survival.

RESULTS

We included 714 patients and among them 140 were colonized (19.6%). Colonized patients more frequently came from ward, had longer hospital length of stay before ICU admission, had unplanned ICU admission, had worse performance status, higher predicted mortality upon ICU admission, and more hematological malignancies than patients without colonization. None of the patients presented conversion of colonization to infection by the same bacteria during hospital stay, but 20.7% presented conversion to infection after hospital discharge. Colonized patients had a higher in-hospital mortality compared to patients without colonization (44.3 vs. 33.4%; p < 0.01), but adjusting for confounders, colonization was not associated with in-hospital mortality [Odds ratio = 1.03 (0.77-1.99)]. Additionally, adjusting for confounders, colonization was not associated with one-year survival [Hazard ratio = 1.10 (0.87-1.40)].

CONCLUSIONS

Adult critically ill patients with active cancer and colonized by carbapenem-resistant Gram-negative bacteria or vancomycin-resistant enterococci active cancer have a worse health status compared to patients without colonization. However, adjusting for confounders, colonization by carbapenem-resistant Gram-negative bacteria or vancomycin-resistant enterococci are not associated with in-hospital mortality and one-year survival.

Intravenous Cyclophosphamide Therapy for Anti-IFN-γ Autoantibody-Associated Talaromyces marneffei Infection

High titers of anti-interferon-γ autoantibodies (AIGAs) are an important factor leading to persistent, relapsed, and refractory infections in HIV-negative hosts infected with Talaromyces marneffei (TM). We report 5 patients treated with pulses of high-dose intravenous cyclophosphamide (IVCY) who were followed for 2 years. Before IVCY therapy, all patients had multiple relapses, with a median (interquartile range [IQR]) of 2 (1-3) instances of relapse. The median serum AIGA titers (IQR) were 58 753 (41 203-89 605) ng/mL at diagnosis, 48 189.4 (15 537-83 375) ng/mL before IVCY therapy, and 10 721.2 (5637-13 245) ng/mL at the end of IVCY therapy (P < .05). After 3 months of follow-up, the median AIGA titers (IQR) rose gradually to 21 232.6 (9896-45 626) ng/mL, and to 37 464.2 (19 872-58 321) ng/mL at 24 months (P < .05). Five patients discontinued antimicrobial therapy within 3-12 months after completion of IVCY therapy, but only 1 patient had a relapse. In conclusion, pulses of short-term and high-dose IVCY can effectively reduce AIGA titers.

Risk factor-based analysis of community-acquired pneumonia, healthcare-associated pneumonia and hospital-acquired pneumonia: Microbiological distribution, antibiotic resistance, and clinical outcomes

Background

Healthcare-associated pneumonia (HCAP) lies in the intersection of community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP). Although HCAP is excluded from the revised HAP guideline, reassessment for HCAP is needed considering its heterogeneous characteristics.

Methods

The microbiological distribution, antibiotic resistance, and clinical outcomes in CAP, HCAP, and HAP were studied retrospectively. The susceptibility to standard CAP regimens (β-lactams plus macrolide or fluoroquinolone monotherapy) and rates of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) infections were evaluated in the CAP group and HCAP subgroups.

Results

In total, 933 cases were included (CAP, n = 557; HCAP, n = 264; HAP, n = 112). In the CAP and HCAP cases, Streptococcus pneumoniae (7.4% vs. 5.7%) and P. aeruginosa (9.2% vs. 18.6%) were the most common gram-positive and gram-negative pathogens. Staphylococcus aureus (methicillin-resistant, 2.7%; methicillin-susceptible, 2.4%) and carbapenem-resistant Acinetobacter baumannii (20.5%) were the most common Gram-positive and Gram-negative pathogens in the HAP group, respectively. Higher susceptibility to levofloxacin was observed in CAP and HCAP isolates than that to β-lactam agents. However, levofloxacin non-susceptibility was significantly higher in long-term care facility (LTCF)-onset HCAP compared to community-onset HCAP (43.6% vs. 22.7%, P = 0.014).

Conclusion

HCAP showed higher rates of P. aeruginosa and MRSA infections than CAP. Empirical antipseudomonal therapy should be considered in the treatment of HCAP. Prior isolation of P. aeruginosa was the most important risk factor for P. aeruginosa infection.

BioFire FilmArray Pneumonia Panel enhances detection of pathogens and antimicrobial resistance in lower respiratory tract specimens

Background

This study investigated the diagnostic utility of the BioFire FilmArray Pneumonia Panel (PN panel), an automated and multiplexed nucleic acid detection system that rapidly detects 26 pathogens (18 bacteria and eight viruses) and seven antimicrobial resistance markers in a single assay.

Methods

We analyzed the targets in lower respiratory tract specimens using the PN panel and compared the detection results with those of bacterial culture methods and antimicrobial susceptibility testing.

Results

Of the 57 samples analyzed, the PN panel detected 97 targets (84 bacteria, four viruses, and nine antimicrobial resistance markers). Detection of bacteria and antimicrobial resistance was three times greater than that of the bacterial culture (25 bacteria and two resistant isolates) against the targets available in the panel. The overall positive and negative percent agreements between the PN panel and culture methods for bacterial detection were 100.0% and 92.9%, respectively. Multiple pathogens were detected by the PN panel in 24 samples (42.1%), ranging from two pathogens in 11 samples (19.3%) to six pathogens in one sample (1.8%). The PN panel semiquantitatively detected higher copies (≥ 106 copies/mL) of bacterial targets if the bacteria were positive by the culture method. In contrast, the semiquantitative values obtained by the panel varied (104 to 107 ≤ copies/mL) among bacteria that were negative by the culture method.

Conclusions

The PN panel enhanced the detection of pathogens and antimicrobial resistance markers in lower respiratory tract specimens.

Surgical site infections caused by multi-drug resistant organisms: a case-control study in general surgery

Multi-drug resistant organisms (MDR-Os) are emerging as a significant cause of surgical site infections (SSI), but clinical outcomes and risk factors associated to MDR-Os-SSI have been poorly investigated in general surgery. Aims were to investigate risk factors, clinical outcomes and costs of care of multi-drug resistant organisms (MDR-Os-SSI) in general surgery. From January 2018 to December 2019, all the consecutive, unselected patients affected by MDR-O SSI were prospectively evaluated. In the same period, patients with non-MDR-O SSI and without SSI, matched for clinical and surgical data were used as control groups. Risk factors for infection, clinical outcome, and costs of care were compared by univariate and multivariate analysis. Among 3494 patients operated on during the study period, 47 presented an MDR-O SSI. Two control groups of 47 patients with non-MDR-O SSI and without SSI were identified. MDR-Os SSI were caused by poly-microbial etiology, meanly related to Gram negative Enterobacteriales. MDR-Os-SSI were related to major postoperative complications. At univariate analysis, iterative surgery, open abdomen, intensive care, hospital stay, and use of aggressive and expensive therapies were associated to MDR-Os-SSI. At multivariate analysis, only iterative surgery and the need of total parenteral and immune-nutrition were significantly associated to MDR-Os-SSI. The extra-cost of MDR-Os-SSI treatment was 150% in comparison to uncomplicated patients. MDR-Os SSI seems to be associated with major postoperative complications and reoperative surgery, they are demanding in terms of clinical workload and costs of care, they are rare but increasing, and difficult to prevent with current strategies.

Risk Factors for Multidrug-Resistant Gram-Negative Bacteria Carriage upon Admission to the Intensive Care Unit

Multidrug-resistant Gram-negative bacteria (MDR-GNB) are microorganisms that have acquired resistance to extended-spectrum antibacterials and constitute an emerging threat to public health. Although carriers are an important source of transmission in healthcare settings, data about risk factors for MDR-GNB carriage are limited. Therefore, we aimed to identify risk factors for MDR-GNB carriage upon intensive care unit (ICU) admission and to optimise screening strategies. We conducted a case–control study. Admissions of adult patients to the ICU of a 1000-bed hospital during a year were included. We collected sociodemographic, clinical and microbiological data and performed a multivariate logistic regression model. A total of 1342 patients resulted in 1476 episodes of ICU admission, 91 (6.2%) of whom harboured MDR-GNB (38.5% women; median age 63.9 years). The most frequently isolated pathogens were Escherichia coli (57%) and Klebsiella pneumoniae (16%). The most frequent resistance mechanism was production of extended-spectrum beta lactamases. MDR-GNB carriage was associated to liver cirrhosis (OR 6.54, 95% CI 2.17–19.17), previous MDR-GNB carriage (OR 5.34, 1.55–16.60), digestive surgery (OR 2.83, 1.29–5.89) and length of hospital stay (OR 1.01 per day, 1.00–1.03). Several risk factors for MDR-GNB carriage upon admission to a high-risk setting were identified; the main comorbidity was liver cirrhosis.

Identification of Risk Factors for Multidrug-Resistant Organisms in Community-Acquired Bacterial Pneumonia at a Community Hospital

Background: The 2019 Infectious Disease Society of America (IDSA) guidelines for the management of community-acquired bacterial pneumonia encourage the identification of locally validated risk factors for methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa to guide empiric therapy decisions for patients with community-acquired pneumonia (CAP). The guidelines urge clinicians to perform local validation to determine prevalence and risk factors pertinent to their institution. Objective: To determine the percentage of community-acquired pneumonia caused by multidrug-resistant organisms (MDROs) and assess risk factors potentially associated with multidrug-resistant organisms CAP at our hospital. Methods: This was a retrospective case control study analyzing patients admitted to the 344-bed community hospital with bacterial community-acquired pneumonia between January 1, 2019 and December 31, 2019. Univariate analysis and multivariate regression were performed to assess potential risk factors for MDRO pathogens. Results: MDROs were isolated in 41.3% of patients with culture-positive CAP (n=19/46), and 3.6% of patients with microbiological culture data within 48 hours of admission (19/527). Among patients with culture-positive CAP, hospitalization in the previous 90 days and receipt of antibiotics in the previous 90 days occurred more frequently in MDRO patients than non-MDRO patients (37% vs 11%, P=.032). No risk factors reached statistical significance in the multivariate regression. There were no differences in clinical outcomes between MDRO and non-MDRO patients. Conclusions: This study demonstrated a low overall prevalence of MDRO pathogens in patients with CAP. Potential risk factors for MDRO included hospitalization within the past 90 days and antibiotic use within the past 90 days.

Talaromyces marneffei and nontuberculous mycobacteria co-infection in HIV-negative patients

To describe the clinical features and the risk factors for nontuberculous mycobacteria (NTM) and Talaromyces marneffei (TM) co-infections in HIV-negative patients. A multicenter retrospective study in 13 hospitals, and a systematic literature review were performed of original articles published in English related to TM/NTM co-infections. HIV-negative patients with TM and NTM co-infections comprised Group 1; TM-only infection Group 2; NTM-only infection Group 3; and healthy volunteers Group 4. Univariate logistic analysis was used to estimate the potential risk factors of TM/NTM co-infections. A total of 22 cases of TM and NTM co-infections were enrolled. Of these, 17 patients (77.3%) had a missed diagnosis of one of the TM or NTM pathogens. The anti-IFN-γ autoantibodies (AIGAs) titer, white blood cell (WBC), neutrophil counts (N), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), globulin, and immunoglobulin G (IgG) levels of Group 1 were higher than those of the other groups, whereas the levels of CD4⁺T cells was lower than those of other groups. There was a significant negative correlation between the AIGA titers and the number of CD4⁺T cells (P < 0.05). Factors including the ratio of the actual values to the cut-off values of AIGAs, WBC, N, HGB, CD4⁺T cells, IgG, IgM, IgA, serum globulin, ESR, and CRP were taken as potential risk factors for TM and NTM co-infection. Most patients with TM and NTM co-infection had a missed diagnosis of one of the TM or NTM pathogens. The levels of AIGAs, WBC, N, ESR, and CRP in TM and NTM co-infections were remarkably higher than in mono-infection. High-titer AIGAs may be a potential risk factor and susceptibility factor for co-infection of TM and NTM in HIV-negative hosts.

Colistin Resistance Development Following Colistin-Meropenem Combination Therapy Versus Colistin Monotherapy in Patients With Infections Caused by Carbapenem-Resistant Organisms

BACKGROUND

We evaluated whether carbapenem-colistin combination therapy reduces the emergence of colistin resistance, compared to colistin monotherapy, when given to patients with infections due to carbapenem-resistant Gram-negative organisms.

METHODS

This is a pre-planned analysis of a secondary outcome from a randomized, controlled trial comparing colistin monotherapy with colistin-meropenem combination for the treatment of severe infections caused by carbapenem-resistant, colistin-susceptible Gram-negative bacteria. We evaluated rectal swabs taken on Day 7 or later for the presence of new colistin-resistant (ColR) isolates. We evaluated the emergence of any ColR isolate and the emergence of ColR Enterobacteriaceae (ColR-E).

RESULTS

Data were available for 214 patients for the primary analysis; emergent ColR organisms were detected in 22 (10.3%). No difference was observed between patients randomized to treatment with colistin monotherapy (10/106, 9.4%) versus patients randomized to colistin-meropenem combination therapy (12/108, 11.1%; P = .669). ColR-E organisms were detected in 18/249 (7.2%) patients available for analysis. No difference was observed between the 2 treatment arms (colistin monotherapy 6/128 [4.7%] vs combination therapy 12/121 [9.9%]; P = .111). Enterobacteriaceae, as the index isolate, was found to be associated with development of ColR-E (hazard ratio, 3.875; 95% confidence interval, 1.475-10.184; P = .006).

CONCLUSIONS

Carbapenem-colistin combination therapy did not reduce the incidence of colistin resistance emergence in patients with infections due to carbapenem-resistant organisms. Further studies are necessary to elucidate the development of colistin resistance and methods for its prevention.

Validating a prediction tool to determine the risk of nosocomial multidrug-resistant Gram-negative bacilli infection in critically ill patients: A retrospective case-control study

BACKGROUND

The Singapore GSDCS score was developed to enable clinicians predict the risk of nosocomial multidrug-resistant Gram-negative bacilli (RGNB) infection in critically ill patients. We aimed to validate this score in a UK setting.

METHOD

A retrospective case-control study was conducted including patients who stayed for more than 24h in intensive care units (ICUs) across two tertiary National Health Service hospitals in London, UK (April 2011-April 2016). Cases with RGNB and controls with sensitive Gram-negative bacilli (SGNB) infection were identified.

RESULTS

The derived GSDCS score was calculated from when there was a step change in antimicrobial therapy in response to clinical suspicion of infection as follows: prior Gram-negative organism, Surgery, Dialysis with end-stage renal disease, prior Carbapenem use and intensive care Stay of more than 5 days. A total of 110 patients with RGNB infection (cases) were matched 1:1 to 110 geotemporally chosen patients with SGNB infection (controls). The discriminatory ability of the prediction tool by receiver operating characteristic curve analysis in our validation cohort was 0.75 (95% confidence interval 0.65-0.81), which is comparable with the area under the curve of the derivation cohort (0.77). The GSDCS score differentiated between low- (0-1.3), medium- (1.4-2.3) and high-risk (2.4-4.3) patients for RGNB infection (P<0.001) in a UK setting.

CONCLUSION

A simple bedside clinical prediction tool may be used to identify and differentiate patients at low, medium and high risk of RGNB infection prior to initiation of prompt empirical antimicrobial therapy in the intensive care setting.

Extensively drug-resistant Acinetobacter baumannii and Proteeae association in a Romanian intensive care unit: risk factors for acquisition

Purpose

The purpose of this study was to identify risk factors for extensively drug-resistant (XDR) Acinetobacter baumannii (AB) and XDR Proteeae association in the largest intensive care unit (ICU) in Western Romania.

Materials and methods

This retrospective case-controlled study was conducted between January 2016 and December 2016 in the ICU of the “Pius Brînzeu” County Emergency Clinical Hospital of Timi oara. Data were collected, in strict confidentiality, from the electronic database of the Microbiology Laboratory and the hospital’s electronic medical records. Risk factors were ș investigated by logistic regression. Independent variables with P≤0.05 and OR >1 (95% CI >1) in the univariate analysis were entered into multivariate sequenced analysis.

Findings

The incidence density of coinfection with XDR AB and XDR Proteeae was 5.31 cases per 1,000 patient-days. Independent risk factors for the association of XDR AB and XDR Proteeae were represented by the presence of tracheostomy and naso-/orogastric nutrition ≥ 8 days. In addition, pressure ulcers were independent predictive factors for infections with all three infection types. Previous antibiotic therapy was an independent risk factor for the acquisition of XDR-AB strains, alone or in association, while the prolonged hospitalization in the ICU, blood transfusion, and hemodialysis appear as independent risk factors for single infections.

Conclusion

This association of XDR AB and XDR Proteeae may well not be limited to our hospital or our geographical area.

Restoration of T Cell function in multi-drug resistant bacterial sepsis after interleukin-7, anti-PD-L1, and OX-40 administration

BACKGROUND

Multidrug resistant (MDR) bacterial pathogens are a serious problem of increasing importance facing the medical community. MDR bacteria typically infect the most immunologically vulnerable: patients in intensive care units, patients with extensive comorbidities, oncology patients, hemodialysis patients, and other immune suppressed individuals are likely to fall victim to these pathogens. One promising novel approach to treatment of MDR bacteria is immuno-adjuvant therapy to boost patient immunity. Success with this strategy would have the major benefit of providing protection against a number of MDR pathogens.

OBJECTIVES

This study had two main objectives. First, immunophenotyping of peripheral blood mononuclear cells from patients with sepsis associated with MDR bacteria was performed to examine for findings indicative of immunosuppression. Second, the ability of three immuno-adjuvants with distinct mechanisms of action to reverse CD4 and CD8 T cell dysfunction, a pathophysiological hallmark of sepsis, was evaluated.

RESULTS

Septic patients with MDR bacteria had increased expression of the inhibitory receptor PD-1 and its ligand PD-L1 and decreased monocyte HLA-DR expression compared to non-septic patients. All three immuno-adjuvants, IL-7, anti-PD-L1, and OX-40L, increased T cell production of IFN-γ in a subset of septic patients with MDR bacteria: IL-7 was most efficacious. There was a strong trend toward increased mortality in patients whose T cells failed to increase IFN-γ production in response to the three treatments.

CONCLUSION

Immuno-adjuvant therapy reversed T cell dysfunction, a key pathophysiological mechanism in septic patients with MDR bacteria.

Full blood count values as a predictor of poor outcome of pneumonia among HIV-infected patients

BACKGROUND

To evaluate the predictive value of analytical markers of full blood count that can be assessed in the emergency department for HIV infected patients, with community-acquired pneumonia (CAP).

METHODS

Prospective 3-year study including all HIV-infected patients that went to our emergency department with respiratory clinical infection, more than 24-h earlier they were diagnosed with CAP and required admission. We assessed the different values of the first blood count performed on the patient as follows; total white blood cells (WBC), neutrophils, lymphocytes (LYM), basophils, eosinophils (EOS), red blood cells (RBC), hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, red blood cell distribution width (RDW), platelets (PLT), mean platelet volume, and platelet distribution width (PDW). The primary outcome measure was 30-day mortality and the secondary, admission to an intensive care unit (ICU). The predictive power of the variables was determined by statistical calculation.

RESULTS

One hundred sixty HIV-infected patients with pneumonia were identified. The mean age was 42 (11) years, 99 (62%) were male, 79 (49%) had ART. The main route of HIV transmission was through parenteral administration of drugs. Streptococcus pneumonia was the most frequently identified etiologic agent of CAP The univariate analysis showed that the values of PLT (p < 0.009), EOS (p < 0.033), RDW (p < 0.033) and PDW (p < 0.09) were predictor of mortality, but after the logistic regression analysis, no variable was shown as an independent predictor of mortality. On the other hand, higher RDW (OR = 1.2, 95% CI 1.1-1.4, p = 0.013) and a lower number of LYM (OR 2.2, 95% CI 1.1-2.2; p = 0.035) were revealed as independent predictors of admission to ICU.

CONCLUSION

Red blood cell distribution and lymphocytes were the most useful predictors of disease severity identifying HIV infected patients with CAP who required ICU admission.

Selection of piperacillin/tazobactam infusion mode guided by SOFA score in cancer patients with hospital-acquired pneumonia: a randomized controlled study

Background

This study aimed to select piperacillin/tazobactam (TZP) infusion mode guided by Sequential Organ Failure Assessment (SOFA) score in cancer patients with hospital-acquired pneumonia (HAP) postoperation.

Patients and methods

A total of 120 cancer patients with postoperative HAP were divided into two groups: improved administration group (L group) and conventional treatment group (Con group). The Con group received traditional infusion of TZP and the L group received it as prolonged infusion. Blood drug concentration was detected at different time points. Based on the SOFA cut-off value of 9, the patients were regrouped into M (mild) and S (severe) groups.

Results

Percent time that the free drug concentrations remain above the minimum inhibitory concentration (%fT>MIC) was longer than 5 h in L group, but <4 h in Con group. Administration method (p=0.033, OX value 2.796, B value 1.028, 95% CI: 0.855-8.934) and SOFA score (p=0.038, OX value 0.080, B value -2.522, 95% CI: 0.007-0.874) were independent predictors of patient survival. In the S group, compared to conventional treatment, prolonged infusion mode resulted in shorter days of antibiotic use and shorter ventilator time, and achieved longer survival, better clinical efficacy, and lower 28-day mortality rate.

Conclusion

For cancer patients with SOFA score ≥9, prolonged infusion of TZP could benefit the patients and obtain better clinical efficacy.

Clinical characteristics and prognostic risk factors of healthcare-associated pneumonia in a Korean tertiary teaching hospital

The 2016 American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) guidelines removed the concept of healthcare-associated pneumonia (HCAP). We examined whether the 2016 ATS/IDSA guidelines are applicable in Korea.We conducted a retrospective, observational study of pneumonia patients who were hospitalized at a tertiary teaching hospital from March 2012 to February 2014. Identified pathogens that were not susceptible to β-lactams, macrolides, and fluoroquinolones were defined as community-acquired pneumonia drug-resistant pathogens (CAP-DRPs). We analyzed the risk factors for 28-day mortality and the occurrence rate of CAP-DRPs.Of the 1046 patients, 399 were classified with HCAP and 647 with CAP. HCAP patients were older and had more comorbidities than CAP patients. Initial pneumonia severity index (PSI) was higher in patients with HCAP than with CAP. HCAP was associated with not only an increased rate of CAP-DRPs (HCAP, 19.8%; CAP, 4.0%; P < .001) but also an increased rate of inappropriate initial antibiotic therapy (IIAT) (HCAP, 16.8%; CAP, 4.6%; P < .001). HCAP was also associated with an increased 28-day mortality rate compared with CAP (HCAP, 14.5%; CAP, 6.3%; P < .001). In a multivariable analysis, PSI was an independent risk factor for 28-day mortality in HCAP patients (odds ratio 1.02, 95% confidence interval 1.01-1.04). CAP-DRPs and IIAT were not associated with mortality.Patients with HCAP revealed higher rates of CAP-DRPs, IIAT, and mortality than patients with CAP. However, CAP-DRPs and IIAT were not associated with mortality. PSI was the main predictive factor for 28-day mortality in patients with HCAP.

Clinical outcomes of intestinal transplant recipients colonized with multidrug-resistant organisms: a retrospective study

Rates of multidrug-resistant organisms (MDRO) colonization among intestinal transplant (ITx) recipients have not been reported. Colonization rates with vancomycin-resistant Enterococcus (VRE), carbapenem-resistant Gram-negative bacteria (CR-GNB), and methicillin-resistant Staphylococcus aureus (MRSA) were obtained retrospectively in adults undergoing ITx (isolated or multivisceral) from 1/2009 to 12/2015. We assessed for VRE, CR-GNB, and MRSA bacteremia during the first year post-transplant for patients colonized with VRE, CR-GNB, and MRSA, respectively, and for those who were not colonized. We evaluated whether the number of hospitalization days and one year post-transplant survival were different in MDRO-colonized patients. Forty-five ITx recipients were identified. Twenty-eight (62%) were colonized with MDRO [VRE in 22 (50%) patients, MRSA in seven (16%), and CR-GNB in six (15%)]. VRE and CR-GNB-colonized patients were more likely to develop VRE and CR-GNB bacteremia, respectively, than noncolonized patients [8/22 (36%) vs. 1/23 (4%), and 4/6 (67%) vs. 2/39 (5%), P < 0.05 for both]. There was no difference in one-year survival between MDRO-colonized and noncolonized patients. However, survival was lower among MDRO-colonized patients who developed VRE, CR-GNB, or MRSA bacteremia (P < 0.001). MDRO colonization was common among our ITx recipients. VRE and CR-GNB bacteremia was more common among colonized patients, and survival was lower among MDRO-colonized patients who developed bacteremia.

Impact of a targeted isolation strategy at intensive-care-unit-admission on intensive-care-unit-acquired infection related to multidrug-resistant bacteria: a prospective uncontrolled before-after study

Isolation of patients with multidrug resistant (MDR) bacteria is recommended to reduce cross-transmission of these bacteria. However, isolation of critically ill patients has several negative side effects. Therefore, we hypothesized that a targeted isolation strategy, based on the presence of at least one risk factor for MDR bacteria, would be not inferior to a systematic isolation strategy at intensive-care unit (ICU) admission. This prospective before-after study was conducted in a mixed ICU, during two 12-month periods, separated by a 1-month 'wash-out' period. During the before period, isolation was systematically performed in all patients at admission. During the after period, isolation was only performed in patients with at least one risk factor for MDR bacteria at admission. During the two periods, routine screening for MDR bacteria was performed at ICU admission, and isolation prescription was modified after receipt of screening result. Primary outcome was the percentage of patients with ICU-acquired infection (ICUAI) related to MDR bacteria, measured from ICU admission until ICU discharge or day 28, whatever happens first. A total of 1221 patients were included. No significant difference was found in ICUAI related to MDR bacteria (85 of 585 (14.5%) vs. 84 of 636 (13.2%) patients, risk difference, -1.3%, 95% confidence interval [-5.2 to 2.6%]) between the two periods, confirming the non-inferiority hypothesis. Our results suggest that targeted isolation of patients at ICU admission is not inferior to systematic isolation, regarding the percentage of patients with ICUAI related to MDR bacteria. Further randomized controlled multicentre studies are needed to confirm our results.

Intermediate risk of multidrug-resistant organisms in patients who admitted intensive care unit with healthcare-associated pneumonia

BACKGROUND/AIMS

Healthcare-associated pneumonia (HCAP) was proposed asa new pneumonia category in 2005, and treatment recommendations includebroad-spectrum antibiotics directed at multidrug-resistant (MDR) pathogens.However, this concept continues to be controversial, and microbiological data arelacking for HCAP patients in the intensive care unit (ICU). This study was conductedto determine the rate and type of antibiotic-resistant organisms and theclinical outcomes in patients with HCAP in the ICU, compared to patients withcommunity-acquired pneumonia (CAP) or hospital-acquired pneumonia (HAP).

METHODS

We conducted a retrospective cohort analysis of patients with pneumonia(n = 195) who admitted to medical ICU in tertiary teaching hospital fromMarch 2011 to February 2013. Clinical characteristics, microbiological distributions,treatment outcomes, and prognosis of HCAP (n = 74) were compared tothose of CAP (n = 75) and HAP (n = 46).

RESULTS

MDR pathogens were significantly higher in HCAP patients (39.1%) thanin CAP (13.5%) and lower than in HAP (79.3%, p < 0.001). The initial use of inappropriateantibiotic treatment occurred more frequently in the HCAP (32.6%) andHAP (51.7%) groups than in the CAP group (11.8%, p = 0.006). There were no differencesin clinical outcomes. The significant prognostic factors were pneumoniaseverity and treatment response.

CONCLUSIONS

MDR pathogens were isolated in HCAP patients requiring ICU admissionat intermediate rates between those of CAP and HAP.

Extensively drug-resistant Acinetobacter baumannii in a Lebanese intensive care unit: risk factors for acquisition and determination of a colonization score

BACKGROUND

Acinetobacter baumannii (AB) has emerged as an important nosocomial pathogen causing worldwide hospital outbreaks. It has become a prototype of extensively drug-resistant (XDR) organisms.

AIM

To identify risk factors for acquisition of XDR-AB and to develop a colonization risk score in intensive care unit (ICU) patients in a Lebanese tertiary care centre where XDR-AB causes intermittent outbreaks.

METHODS

This retrospective study included 257 patients with baseline negative screening cultures for XDR-AB admitted to a seven-bed ICU from July 2012 to July 2013. Patients' demographic data and clinical characteristics were collected from the hospital's electronic medical records. Univariate analysis of potential risk factors was performed followed by multivariate analysis to determine parameters to be included in the colonization risk score.

FINDINGS

The rate of XDR-AB acquisition was 15.6%. Multivariate analysis identified urinary catheter placement >6 days (odds ratio: 16.98; 95% confidence interval: 3.96-49.56; P<0.0001), ICU contact pressure for >4 days (2.38; 1.48-3.57; P=0.001), presence of gastrostomy tube (5.44; 1.43-20.68; P=0.013), and previous use of carbapenems or piperacillin-tazobactam (4.20; 1.65-11.81; P=0.002) as parameters to be included in the colonization score. The risk of XDR-AB acquisition was 0, 5.6%, 17.2%, 56.8%, and 80% in the presence of a score of 0, 1, 2, 3, and 4 respectively. A score of 4 indicates high probability of XDR-AB acquisition, suggesting that patient isolation is required; zero indicates a low probability of XDR-AB acquisition.

CONCLUSION

Risk factors could be used to develop a score to decide which patients need isolation to limit the spread of XDR-AB.

Colonization of Klebsiella pneumoniae inside fistula tracts: a possible risk factor for failure of fibrin glue-assisted closure

GOALS

This study was designed to investigate the risk factors affecting glue-assisted closure (GAC) in the enterocutaneous fistula (ECF) patients receiving glue application.

BACKGROUND

ECF is a challenging problem in surgical practice, and it is difficult to resolve by spontaneous closure. Currently, GAC is popular when treating fistulas, but data related to risk factors are limited.

METHODS

We retrospectively analyzed 82 patients with 93 ECFs, who had autologous glue sealing from 2010 to 2012 in a referral center. Their demographic data, clinical records, and fistula characteristics were collected. Both univariate analysis and multivariate Cox proportional hazards model were used to determine the prognostic factors affecting closure.

RESULTS

During the 14-day treatment period, 78.5% (73/93) of the fistulas achieved GAC. We excluded 3 reopened fistulas and investigated 90 ECFs from 79 patients. Univariate analysis demonstrated that patients with high levels of CRP, high CRP:prealbumin ratio, elevated blood glucose, and specific pathogen colonization, together with lower GI location, greater output volume, and shorter tract length, had a poor outcome (P<0.05). Using multivariate analysis, monomicrobial and polymicrobial colonization with Klebsiella pneumoniae inside the fistula tracts (hazard ratio, 0.191; 95% confidence interval, 0.045-0.810; P=0.025) was a statistically significant risk factor for failure of fistula closure.

CONCLUSIONS

The presence of monomicrobial and polymicrobial colonization with K. pneumoniae in fistulous tracts was an independent risk factor for failure of GAC in patients receiving glue application. Better debridement of the tracts should be performed before the glue sealing.

Optimization of pre-emptive isolations in a polyvalent ICU through implementation of an intervention strategy

BACKGROUND

Pre-emptive isolation refers to the application of contact precaution measures in patients with strongly suspected colonization by multiresistant bacteria.

OBJECTIVE

To assess the impact of an intervention program involving the implementation of a consensus-based protocol of pre-emptive isolation (CPPI) on admission to a polyvalent ICU of a general hospital.

METHODS

A comparative analysis of 2 patient cohorts was made: a historical cohort including patients in which pre-emptive isolation was established according to physician criterion prior to starting CPPI (from January 2010 to February 2011), and a prospective cohort including patients in which CPPI was implemented (from March to November 2011). CPPI included the identification and diffusion of pre-emptive isolation criteria, the definition of sampling methodology, the evaluation of results, and the development of criteria for discontinuation of pre-emptive isolation. Pre-emptive isolation was indicated by the medical staff, and follow-up was conducted by the nursing staff. Pre-emptive isolation was defined as "adequate" when at least one multiresistant bacteria was identified in any of the samples. Comparison of data between the 2 periods was made with the chi-square test for categorical variables and the Student t-test for quantitative variables. Statistical significance was set at P<.05.

RESULTS

Among the 1,740 patients admitted to the ICU (1,055 during the first period and 685 during the second period), pre-emptive isolation was indicated in 199 (11.4%); 111 (10.5%) of these subjects corresponded to the historical cohort (control group) and 88 (12.8%) to the posterior phase after the implementation of CPPI (intervention group). No differences were found in age, APACHE II score or patient characteristics between the 2 periods. The implementation of CPPI was related to decreases in non-indicated pre-emptive isolations (29.7 vs. 6.8%, P<.001), time of requesting surveillance cultures (1.56 vs. 0.37 days, P<.001), and days of duration of treatment (4.77 vs. 3.58 days, P<.001). In 44 patients (22.1%) in which pre-emptive isolation was indicated, more than one multiresistant bacteria was identified, with an "adequate pre-emptive isolation rate" of 19.8% in the first period and 25.0% in the second period (P<.382).

CONCLUSIONS

The implementation of CPPI resulted in a significant decrease in pre-emptive isolations which were not indicated correctly, a decrease in the time elapsed between isolation and collection of samples, and a decrease in the duration of isolation measures in cases in which isolation was unnecessary, without increasing the rate of "adequate pre-emptive isolation".

Combatting resistance in intensive care: the multimodal approach of the Spanish ICU "Zero Resistance" program

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Patient-level interventions to prevent the acquisition of resistant gram-negative bacteria in critically ill patients: a systematic review

The rising incidence of multidrug-resistant Gram-negative bacterial (MDR-GNB) infections acquired in intensive care units has prompted a variety of patient-level infection control efforts. However, it is not known whether these measures are effective in reducing colonisation and infection. The purpose of this systematic review was to assess the efficacy of patient-level interventions for the prevention of colonisation with MDR-GNB and whether these interventions are associated with a reduction in the rate of infection due to MDR-GNB in the intensive care unit. Searches were conducted on PubMed, Cochrane, EMBASE and World of Science databases to identify comparative interventional studies on patient-level interventions implemented in the intensive care unit. Literature published in English, Spanish or French from January 1, 2000, until April 30, 2013, was searched. A total of 631 reports were found and we included and analysed 13 comparative studies that reported outcomes for an intervention compared with a control group. There were ten randomised and three observational interventional trials evaluating seven interventions. Overall, there was a reduction in colonisation (odds ratio [OR] 0.75; 95% confidence interval [CI] 0.66 to 0.85) and infection (OR 0.66; 95% CI 0.59 to 0.75) with MDR-GNB. This trend persisted after restricting pooled analysis to randomised controlled trials (pooled OR 0.66; 95% CI 0.57 to 0.76 and pooled OR 0.62; 95% CI 0.54 to 0.72, respectively). We identified a significant reduction in MDR-GNB colonisation and infection through the use of patient-level interventions. This effect was mostly accounted for by selective digestive decontamination. However, given the limitations of the analysed trials, adequately powered controlled studies are needed to further explore the effects of patient-level interventions on colonisation and infection with MDR-GNB.

A propensity score analysis shows that empirical treatment with linezolid does not increase the thirty-day mortality rate in patients with Gram-negative bacteremia

The role of linezolid in empirical therapy of suspected bacteremia remains unclear. The aim of this study was to evaluate the influence of empirical use of linezolid or glycopeptides in addition to other antibiotics on the 30-day mortality rates in patients with Gram-negative bacteremia. For this purpose, 1,126 patients with Gram-negative bacteremia in the Hospital Clinic of Barcelona from 2000 to 2012 were included in this study. In order to compare the mortality rates between patients who received linezolid or glycopeptides, the propensity scores on baseline variables were used to balance the treatment groups, and both propensity score matching and propensity-adjusted logistic regression were used to compare the 30-day mortality rates between the groups. The overall 30-day mortality rate was 16.0% during the study period. Sixty-eight patients received empirical treatment with linezolid, and 1,058 received glycopeptides. The propensity score matching included 64 patients in each treatment group. After matching, the mortality rates were 14.1% (9/64) in patients who received glycopeptides and 21.9% (14/64) in those who received linezolid, and a nonsignificant association between empirical linezolid treatment and mortality rate (odds ratio [OR], 1.63; 95% confidence interval [CI], 0.69 to 3.82; P = 0.275, McNemar's test) was found. This association remained nonsignificant when variables that remained unbalanced after matching were included in a conditional logistic regression model. Further, the stratified propensity score analysis did not show any significant relationship between empirical linezolid treatment and the mortality rate after adjustment by propensity score quintiles or other variables potentially associated with mortality. In conclusion, the propensity score analysis showed that empirical treatment with linezolid compared with that with glycopeptides was not associated with 30-day mortality rates in patients with Gram-negative bacteremia.

Value of American Thoracic Society guidelines in predicting infection or colonization with multidrug-resistant organisms in critically ill patients

Background

The incidence rate of infection by multidrug-resistant organisms (MDROs) can affect the accuracy of etiological diagnosis when using American Thoracic Society (ATS) guidelines. We determined the accuracy of the ATS guidelines in predicting infection or colonization by MDROs over 18 months at a single ICU in eastern China.

Methods

This prospective observational study examined consecutive patients who were admitted to an intensive care unit (ICU) in Nanjing, China. MDROs were defined as bacteria that were resistant to at least three antimicrobial classes, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Pseudomonas aeruginosa, Acinetobacter baumannii. Screening for MDROs was performed at ICU admission and discharge. Risk factors for infection or colonization with MDROs were recorded, and the accuracy of the ATS guidelines in predicting infection or colonization with MDROs was documented.

Results

There were 610 patients, 225 (37%) of whom were colonized or infected with MDROs at ICU admission, and this increased to 311 (51%) at discharge. At admission, the sensitivity (70.0%), specificity (31.6%), positive predictive value (38.2%), and negative predictive value (63.5%), all based on ATS guidelines for infection or colonization with MDROs were low. The negative predictive value was greater in patients from departments with MDRO infection rates of 31–40% than in patients from departments with MDRO infection rates of 30% or less and from departments with MDRO infection rates more than 40%.

Conclusion

ATS criteria were not reliable in predicting infection or colonization with MDROs in our ICU. The negative predictive value was greater in patients from departments with intermediate rates of MDRO infection than in patients from departments with low or high rates of MDRO infection.

Trial Registration

ClinicalTrials.gov NCT01667991

The prevalence and significance of methicillin-resistant Staphylococcus aureus colonization at admission in the general ICU Setting: a meta-analysis of published studies

OBJECTIVE

To estimate the prevalence and significance of nasal methicillin-resistant Staphylococcus aureus colonization in the ICU and its predictive value for development of methicillin-resistant S. aureus infection.

DATA SOURCES

MEDLINE and EMBASE and reference lists of all eligible articles.

STUDY SELECTION

Studies providing raw data on nasal methicillin-resistant S. aureus colonization at ICU admission, published up to February 2013. Analyses were restricted in the general ICU setting. Medical, surgical, and interdisciplinary ICUs were eligible. ICU studies referring solely on highly specialized ICUs populations and reports on methicillin-resistant S. aureus outbreaks were excluded.

DATA EXTRACTION

Two authors independently assessed study eligibility and extrapolated data in a blinded fashion. The two outcomes of interest were the prevalence estimate of methicillin-resistant S. aureus nasal colonization at admission in the ICU and the sensitivity/specificity of colonization in predicting methicillin-resistant S. aureus-associated infections.

DATA SYNTHESIS

Meta-analysis, using a random-effect model, and meta-regression were performed. Pooled data extracted from 63,740 evaluable ICU patients provided an estimated prevalence of methicillin-resistant S. aureus nasal colonization at admission of 7.0% (95% CI, 5.8-8.3). Prevalence was higher for North American studies (8.9%; 95% CI, 7.1-10.7) and for patients screened using polymerase chain reaction (14.0%; 95% CI, 9.6-19). A significant per year increase in methicillin-resistant S. aureus colonization was also noted. In 17,738 evaluable patients, methicillin-resistant S. aureus infections (4.1%; 95% CI, 2.0-6.8) developed in 589 patients. The relative risk for colonized patients was 8.33 (95% CI, 3.61-19.20). Methicillin-resistant S. aureus nasal carriage had a high specificity (0.96; 95% CI, 0.90-0.98) but low sensitivity (0.32; 95% CI, 0.20-0.48) to predict methicillin-resistant S. aureus-associated infections, with corresponding positive and negative predictive values at 0.25 (95% CI, 0.11-0.39) and 0.97 (95% CI, 0.83-1.00), respectively.

CONCLUSIONS

Among ICU patients, 5.8-8.3% of patients are colonized by methicillin-resistant S. aureus at admission, with a significant upward trend. Methicillin-resistant S. aureus colonization is associated with a more than eight-fold increase in the risk of associated infections during ICU stay, and methicillin-resistant S. aureus infection develops in one fourth of patients who are colonized with methicillin-resistant S. aureus at admission to the ICU.

Withdrawal of Staphylococcus aureus from intensive care units in Turkey

BACKGROUND

In the past, Staphylococcus aureus infections have displayed various patterns of epidemiologic curves in hospitals, particularly in intensive care units (ICUs). This study aimed to characterize the current trend in a nationwide survey of ICUs in Turkey.

METHODS

A total of 88 ICUs from 36 Turkish tertiary hospitals were included in this retrospective study, which was performed during the first 3 months of both 2008 (period [P] 1) and 2011 (P2). A P value ≤.01 was considered significant.

RESULTS

Although overall rates of hospital-acquired infection (HAI) and device-associated infection densities were similar in P1 and P2, the densities of HAIs due to S aureus and methicillin-resistant S aureus (MRSA) were significantly lower in P2 (P < .0001). However, the proportion of HAIs due to Acinetobacter was significantly higher in P2 (P < .0001).

CONCLUSIONS

The incidence of S aureus infections is declining rapidly in Turkish ICUs, with potential impacts on empirical treatment strategies in these ICUs.

Guideline-based antibiotics and mortality in healthcare-associated pneumonia

BACKGROUND

Guidelines recommend administration of antibiotics with activity against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa for treatment of healthcare-associated pneumonia (HCAP). It is unclear if this therapy improves outcomes for patients with HCAP.

OBJECTIVE

To determine if administration of guideline-similar therapy (GST) was associated with a reduction in 30-day mortality for HCAP.

DESIGN

Multi-center retrospective study.

PARTICIPANTS

Thirteen hundred and eleven admissions for HCAP in six Veterans Affairs Medical Centers.

INTERVENTIONS

Each admission was classified as receiving GST, anti-MRSA or anti-pseudomonal components of GST, or other non-HCAP therapy initiated within 48 hours of hospitalization. Association between 30-day mortality and GST was estimated with a logistic regression model that included GST, propensity to receive GST, probability of recovering an organism from culture resistant to antibiotics traditionally used to treat community-acquired pneumonia (CAP-resistance), and a GST by CAP-resistance probability interaction.

MAIN MEASURES

Odds ratios and 95% confidence intervals [OR (95% CI)] of 30-day mortality for patients treated with GST and predicted probability of recovering a CAP-resistant organism, and ratio of odds ratios [ROR (95% CI)] for treatment by CAP-resistance probability interaction.

KEY RESULTS

Receipt of GST was associated with increased odds of 30-day mortality [OR = 2.11 (1.11, 4.04), P = 0.02)] as was the predicted probability of recovering a CAP-resistant organism [OR = 1.67 (1.26, 2.20), P < 0.001 for a 25% increase in probability]. An interaction between predicted probability of recovering a CAP-resistant organism and receipt of GST demonstrated lower mortality with GST at high probability of CAP resistance [ROR = 0.71(≤1.00) for a 25% increase in probability, P = 0.05].

CONCLUSIONS

For HCAP patients with high probability of CAP-resistant organisms, GST was associated with lower mortality. Consideration of the magnitude of patient-specific risk for CAP-resistant organisms should be considered when selecting HCAP therapy.

The importance of colonization pressure in multiresistant Acinetobacter baumannii acquisition in a Greek intensive care unit

INTRODUCTION

We investigated the role of colonization pressure on multiresistant Acinetobacter baumannii acquisition and defined patient-related predictors for carriage at admission and acquisition during hospitalization in intensive care unit (ICU) patients.

METHODS

This was a 12-month, prospective, cohort study of all patients admitted to a single ICU of a tertiary hospital. Screening samples were collected at ICU admission to identify imported carriers, and weekly during hospitalization to identify acquisition. Colonization pressure (carriers' patient-days × 100/all patients' patient-days) and the absolute number of carriers were calculated weekly, and the statistical correlation between these parameters and acquisition was explored. Multivariable analysis was performed to identify predictors for A. baumannii carriage at admission and acquisition during hospitalization. A. baumannii isolates were genotyped by repetitive-extragenic-palindromic polymerase chain reaction (PCR; rep-PCR).

RESULTS

At ICU admission, 284 patients were screened for carriage. A. baumannii was imported in 16 patients (5.6%), and acquisition occurred in 32 patients (15.7%). Acquisition was significantly correlated to weekly colonization pressure (correlation coefficient, 0.379; P = 0.004) and to the number of carriers per week (correlation coefficient, 0.499; P <0.001). More than one carrier per week significantly increased acquisition risk (two to three carriers, odds ratio (OR), 12.66; P = 0.028; more than four carriers, OR, 25.33; P = 0.004). Predictors of carriage at admission were infection at admission (OR, 11.03; confidence interval (CI), 3.56 to 34.18; P < 0.01) and hospitalization days before ICU (OR, 1.09; CI, 1.01 to 1.16; P = 0.02). Predictors of acquisition were a medical reason for ICU admission (OR, 5.11; CI, 1.31 to 19.93; P = 0.02), duration of antibiotic administration in the unit (OR, 1.24; CI, 1.12 to 1.38; P < 0.001), and duration of mechanical ventilation (OR, 1.08; CI, 1.04 to 1.13; P = 0.001). All strains were multiresistant. Rep-PCR analysis showed one dominant cluster.

CONCLUSIONS

Acquisition of multiresistant A. baumannii in ICU patients is strongly correlated to colonization pressure. High levels of colonization pressure and more than two carriers per week independently increase acquisition risk. Patient-related factors, such as infection at admission and long hospitalization before the ICU, can identify imported A. baumannii carriers. Medical patients with extended administration of antibiotics and long duration of mechanical ventilation in the ICU were the most vulnerable to acquisition.

Risk factors for developing clinical infection with carbapenem-resistant Klebsiella pneumoniae in hospital patients initially only colonized with carbapenem-resistant K pneumoniae

BACKGROUND

This study examined predictors of carbapenem-resistant Klebsiella pneumoniae (CRKP) colonization and risk factors for the development of CRKP infection in patients initially only colonized with CRKP.

METHODS

A total of 464 patients with CRKP rectal colonization (CRKP-RC) were identified. Two case-control studies were performed, one comparing risk factors for CRKP-RC in patients who did not develop CRKP infection (CRKP-IN) versus patients without CRKP-RC and CRKP-IN, and the other comparing CRKP-RC patients who did not develop CRKP-IN with those who did.

RESULTS

Forty-two of the 464 colonized patients developed CRKP-IN. Multivariate analysis identified the following predictors for CRKP-RC: antibiotic therapy (odds ratio [OR], 5.76; P ≤ .0001), aminopenicillin therapy (OR, 7.753; P = .004), bedridden (OR, 3.09; P = .021), and nursing home residency (OR, 3.09; P = .013). Risk factors for CRKP-IN in initially CRKP-RC-positive patients were previous invasive procedure (OR, 5.737; P = .021), diabetes mellitus (OR, 4.362; P = .017), solid tumor (OR, 3.422; P = .025), tracheostomy (OR, 4.978; P = .042), urinary catheter insertion (OR, 4.696; P = .037), and antipseudomonal penicillin (OR, 23.09; P ≤ .0001).

CONCLUSIONS

We suggest that in patients with CRKP-RC, a strategy for preventing CRKP-IN might include limiting antipseudomonal penicillin and carbapenem use and preventing infections by closely following compliance with infection control bundles.

Predicting antibiotic resistance to community-acquired pneumonia antibiotics in culture-positive patients with healthcare-associated pneumonia

OBJECTIVE

To develop and validate a model to predict resistance to community-acquired pneumonia antibiotics (CAP-resistance) among patients with healthcare-associated pneumonia (HCAP), and to compare the model's predictive performance to a model including only guideline-defined criteria for HCAP.

DESIGN

Retrospective cohort study.

SETTING

Six Veterans Affairs Medical Centers in the northwestern United States.

PATIENTS

Culture-positive inpatients with HCAP.

MEASUREMENTS

Patients were identified based upon guideline-defined criteria for HCAP. Relevant cultures obtained within 48 hours of admission were assessed to determine bacteriology and antibiotic susceptibility. Medical records for the year preceding admission were assessed to develop predictive models of CAP-resistance with logistic regression. The predictive performance of cohort-developed and guideline-defined models was compared.

RESULTS

CAP-resistant organisms were identified in 118 of 375 culture-positive patients. Of guideline-defined criteria, CAP-resistance was associated (odds ratio (OR) [95% confidence interval (CI)]) with: admission from nursing home (2.6 [1.6-4.4]); recent antibiotic exposure (1.7 [1.0-2.8]); and prior hospitalization (1.6 [1.0-2.6]). In the cohort-developed model, CAP-resistance was associated with: admission from nursing home or recent nursing home discharge (2.3 [1.4-3.8]); positive methicillin-resistant Staphylococcus aureus (MRSA) history within 90 days of admission (6.4 [2.6-17.8]) or 91-365 days (2.3 [0.9-5.9]); cephalosporin exposure (1.8 [1.1-2.9]); recent infusion therapy (1.9 [1.0-3.5]); diabetes (1.7 [1.0-2.8]); and intensive care unit (ICU) admission (1.6 [1.0-2.6]). Area under the receiver operating characteristic curve (aROC [95% CI]) for the cohort-developed model (0.71 [0.65-0.77]) was significantly higher than for the guideline-defined model (0.63 [0.57-0.69]) (P = 0.01).

CONCLUSIONS

Select guideline-defined criteria predicted CAP-resistance. A cohort-developed model based primarily on prior MRSA history, nursing home residence, and specific antibiotic exposures provided improved prediction of CAP-resistant organisms in HCAP.

Appraising contemporary strategies to combat multidrug resistant gram-negative bacterial infections--proceedings and data from the Gram-Negative Resistance Summit

The emerging problem of antibiotic resistance, especially among Gram-negative bacteria (GNB), has become a serious threat to global public health. Very few new antibacterial classes with activity against antibiotic-resistant GNB have been brought to market. Renewed and growing attention to the development of novel compounds targeting antibiotic-resistant GNB, as well as a better understanding of strategies aimed at preventing the spread of resistant bacterial strains and preserving the efficacy of existing antibiotic agents, has occurred. The Gram-Negative Resistance Summit convened national opinion leaders for the purpose of analyzing current literature, epidemiologic trends, clinical trial data, therapeutic options, and treatment guidelines related to the management of antibiotic-resistant GNB infections. After an in-depth analysis, the Summit investigators were surveyed with regard to 4 clinical practice statements. The results then were compared with the same survey completed by 138 infectious disease and critical care physicians and are the basis of this article.

Stratifying risk factors for multidrug-resistant pathogens in hospitalized patients coming from the community with pneumonia

BACKGROUND

 Not all risk factors for acquiring multidrug-resistant (MDR) organisms are equivalent in predicting pneumonia caused by resistant pathogens in the community. We evaluated risk factors for acquiring MDR bacteria in patients coming from the community who were hospitalized with pneumonia. Our evaluation was based on actual infection with a resistant pathogen and clinical outcome during hospitalization.

METHODS

 An observational, prospective study was conducted on consecutive patients coming from the community who were hospitalized with pneumonia. Data on admission and during hospitalization were collected. Logistic regression models were used to evaluate risk factors for acquiring MDR bacteria independently associated with the actual presence of a resistant pathogen and in-hospital mortality.

RESULTS

 Among the 935 patients enrolled in the study, 473 (51%) had at least 1 risk factor for acquiring MDR bacteria on admission. Of all risk factors, hospitalization in the preceding 90 days (odds ratio [OR], 4.87 95% confidence interval {CI}, 1.90-12.4]; P = .001) and residency in a nursing home (OR, 3.55 [95% CI, 1.12-11.24]; P = .031) were independent predictors for an actual infection with a resistant pathogen. A score able to predict pneumonia caused by a resistant pathogen was computed, including comorbidities and risk factors for MDR. Hospitalization in the preceding 90 days and residency in a nursing home were also independent predictors for in-hospital mortality.

CONCLUSIONS

 Risk factors for acquiring MDR bacteria should be weighted differently, and a probabilistic approach to identifying resistant pathogens among patients coming from the community with pneumonia should be embraced.

Healthcare-associated pneumonia: diagnostic criteria and distinction from community-acquired pneumonia

BACKGROUND

Traditionally, pneumonia developing in patients who receive healthcare services in the outpatient environment has been classified as community-acquired pneumonia (CAP). However, recent investigations suggest that this type of infection, known as healthcare-associated pneumonia (HCAP), is distinct from CAP in terms of its epidemiology, etiology, and risk for infection with multidrug-resistant (MDR) pathogens.

METHODS

A Medline literature review of available clinical studies using the term HCAP was conducted to determine outcomes compared to CAP and effective empiric treatment strategies.

RESULTS

Analysis of multi-institutional clinical data showed that mortality in hospitalized patients with HCAP is greater than that in CAP, and patients with HCAP received inappropriate initial empiric antibiotic treatment more frequently than CAP patients. The bacterial pathogens associated with HCAP also differed from CAP with potentially MDR Gram-positive and Gram-negative bacteria being more common in HCAP.

CONCLUSIONS

All patients hospitalized with suspected HCAP should be evaluated for their underlying risk of infection with MDR pathogens. Because HCAP is similar to hospital-acquired pneumonia (HAP), both clinically and etiologically, it should be treated as HAP until culture data become available.

Overview of antimicrobial therapy in intensive care units

In the management of a patient with severe sepsis, it is important to suspect the infection early, to collect samples immediately after diagnosis and to promptly initiate a broad-spectrum antibiotic treatment. The choice of this empirical antimicrobial therapy should be based on host characteristics, site of infection, local ecology and pharmacokinetics/pharmacodynamics of antibiotics. In severe infection, guidelines recommend the use of a combination of antibiotics. After results of cultures are obtained, treatment should be re-evaluated to either de-escalate or escalate the antibiotic prescription. This is associated with optimal costs, decreased incidence of superinfection and minimal development of antimicrobial resistance. All these steps should rely on written protocols, and the compliance to these protocols should be continuously monitored in order to detect violations and implement corrective procedures.

Hospital epidemiology and infection control in acute-care settings

Health care-associated infections (HAIs) have become more common as medical care has grown more complex and patients have become more complicated. HAIs are associated with significant morbidity, mortality, and cost. Growing rates of HAIs alongside evidence suggesting that active surveillance and infection control practices can prevent HAIs led to the development of hospital epidemiology and infection control programs. The role for infection control programs has grown and continues to grow as rates of antimicrobial resistance rise and HAIs lead to increasing risks to patients and expanding health care costs. In this review, we summarize the history of the development of hospital epidemiology and infection control, common HAIs and the pathogens causing them, and the structure and role of a hospital epidemiology and infection control program.

Risk of acquiring multidrug-resistant Gram-negative bacilli from prior room occupants in the intensive care unit

The objective of this prospective cohort study was to determine whether admission to an intensive care unit (ICU) room previously occupied by a patient with multidrug-resistant (MDR) Gram-negative bacilli (GNB) increases the risk of acquiring these bacteria by subsequent patients. All patients hospitalized for >48 h were eligible. Patients with MDR GNB at ICU admission were excluded. The MDR GNB were defined as MDR Pseudomonas aeruginosa, Acinetobacter baumannii and extended spectrum β-lactamase (ESBL) -producing GNB. All patients were hospitalized in single rooms. Cleaning of ICU rooms between two patients was performed using quaternary ammonium disinfectant. Risk factors for MDR P. aeruginosa, A. baumannii and ESBL-producing GNB were determined using univariate and multivariate analysis. Five hundred and eleven consecutive patients were included; ICU-acquired MDR P. aeruginosa was diagnosed in 82 (16%) patients, A. baumannii in 57 (11%) patients, and ESBL-producing GNB in 50 (9%) patients. Independent risk factors for ICU-acquired MDR P. aeruginosa were prior occupant with MDR P. aeruginosa (OR 2.3, 95% CI 1.2-4.3, p 0.012), surgery (OR 1.9, 95% CI 1.1-3.6, p 0.024), and prior piperacillin/tazobactam use (OR 1.2, 95% CI 1.1-1.3, p 0.040). Independent risk factors for ICU-acquired A. baumannii were prior occupant with A. baumannii (OR 4.2, 95% CI 2-8.8, p <0.001), and mechanical ventilation (OR 9.3, 95% CI 1.1-83, p 0.045). Independent risk factors for ICU-acquired ESBL-producing GNB were tracheostomy (OR 2.6, 95% CI 1.1-6.5, p 0.049), and sedation (OR 6.6, 95% CI 1.1-40, p 0.041). We conclude that admission to an ICU room previously occupied by a patient with MDR P. aeruginosa or A. baumannii is an independent risk factor for acquisition of these bacteria by subsequent room occupants. This relationship was not identified for ESBL-producing GNB.

Systematic review and meta-analysis of the efficacy of appropriate empiric antibiotic therapy for sepsis

Quantifying the benefit of early antibiotic treatment is crucial for decision making and can be assessed only in observational studies. We performed a systematic review of prospective studies reporting the effect of appropriate empirical antibiotic treatment on all-cause mortality among adult inpatients with sepsis. Two reviewers independently extracted data. Risk of bias was assessed using the Newcastle-Ottawa score. We calculated unadjusted odds ratios (ORs) with 95% confidence intervals for each study and extracted adjusted ORs, with variance, methods, and covariates being used for adjustment. ORs were pooled using random-effects meta-analysis. We examined the effects of methodological and clinical confounders on results through subgroup analysis or mixed-effect meta-regression. Seventy studies were included, of which 48 provided an adjusted OR for inappropriate empirical antibiotic treatment. Inappropriate empirical antibiotic treatment was associated with significantly higher mortality in the unadjusted and adjusted comparisons, with considerable heterogeneity occurring in both analyses (I(2) > 70%). Study design, time of mortality assessment, the reporting methods of the multivariable models, and the covariates used for adjustment were significantly associated with effect size. Septic shock was the only clinical variable significantly affecting results (it was associated with higher ORs). Studies adjusting for background conditions and sepsis severity reported a pooled adjusted OR of 1.60 (95% confidence interval = 1.37 to 1.86; 26 studies; number needed to treat to prevent one fatal outcome, 10 patients [95% confidence interval = 8 to 15]; I(2) = 46.3%) given 34% mortality with inappropriate empirical treatment. Appropriate empirical antibiotic treatment is associated with a significant reduction in all-cause mortality. However, the methods used in the observational studies significantly affect the effect size reported. Methods of observational studies assessing the effects of antibiotic treatment should be improved and standardized.