Bloodstream infection in the ICU. Infect Dis Clin North Am. 2009;23:557-569. [PMID: 19665083 DOI: 10.1016/j.idc.2009.04.005]

Carbapenem-resistant Gram-negative bacteria (CR-GNB) in ICUs: resistance genes, therapeutics, and prevention - a comprehensive review

Intensive care units (ICUs) are specialized environments dedicated to the management of critically ill patients, who are particularly susceptible to drug-resistant bacteria. Among these, carbapenem-resistant Gram-negative bacteria (CR-GNB) pose a significant threat endangering the lives of ICU patients. Carbapenemase production is a key resistance mechanism in CR-GNB, with the transfer of resistance genes contributing to the extensive emergence of antimicrobial resistance (AMR). CR-GNB infections are widespread in ICUs, highlighting an urgent need for prevention and control measures to reduce mortality rates associated with CR-GNB transmission or infection. This review provides an overview of key aspects surrounding CR-GNB within ICUs. We examine the mechanisms of bacterial drug resistance, the resistance genes that frequently occur with CR-GNB infections in ICU, and the therapeutic options against carbapenemase genotypes. Additionally, we highlight crucial preventive measures to impede the transmission and spread of CR-GNB within ICUs, along with reviewing the advances made in the field of clinical predictive modeling research, which hold excellent potential for practical application.

Bloodstream infection clusters for critically ill patients: analysis of two-center retrospective cohorts

BACKGROUND

Bloodstream infections (BSI) are highly prevalent in hospitalized patients requiring intensive care. They are among the most serious infections and are highly associated with sepsis or septic shock, which can lead to prolonged hospital stays and high healthcare costs. This study aimed at establishing an easy-to-use nomogram for predicting the prognosis of patients with BSI.

METHODS

In retrospective study, records of patients with BSI admitted to the intensive care unit (ICU) over the period from Jan 1st 2016 to Dec 31st 2021 were included. We used data from two different China hospitals as development cohort and validation cohort respectively. The demographic and clinical data of patients were collected. Based on all baseline data, k-means algorithm was applied to discover the groups of BSI phenotypes with different prognostic outcomes, which was confirmed by Kaplan-Meier analysis and compared using log-rank tests. Univariate Cox regression analyses were used to estimate the risk of clusters. Random forest was used to identified discriminative predictors in clusters, which were utilized to construct nomogram based on multivariable logistic regression in the discovery cohort. For easy clinical applications, we developed a bloodstream infections clustering (BSIC) score according to the nomogram. The results were validated in the validation cohort over a similar period.

RESULTS

A total of 360 patients in the discovery cohort and 310 patients in the validation cohort were included in statistical analyses. Based on baseline variables, two distinct clusters with differing prognostic outcomes were identified in the discovery cohort. Population in cluster 1 was 211 with a ICU mortality of 17.1%, while population in cluster 2 was 149 with an ICU mortality of 41.6% (p < 0.001). The survival analysis also revealed a higher risk of death for cluster 2 when compared with cluster 1 (hazard ratio: 2.31 [95% CI, 1.53 to 3.51], p < 0.001), which was confirmed in validation cohort. Four independent predictors (vasoconstrictor use before BSI, mechanical ventilation (MV) before BSI, Deep vein catheterization (DVC) before BSI, and antibiotic use before BSI) were identified and used to develop a nomogram. The nomogram and BSIC score showed good discrimination with AUC of 0.96.

CONCLUSION

The developed score has potential applications in the identification of high-risk critically ill BSI patients.

A high-speed microscopy system based on deep learning to detect yeast-like fungi cells in blood

Background: Blood-invasive fungal infections can cause the death of patients, while diagnosis of fungal infections is challenging. Methods: A high-speed microscopy detection system was constructed that included a microfluidic system, a microscope connected to a high-speed camera and a deep learning analysis section. Results: For training data, the sensitivity and specificity of the convolutional neural network model were 93.5% (92.7-94.2%) and 99.5% (99.1-99.5%), respectively. For validating data, the sensitivity and specificity were 81.3% (80.0-82.5%) and 99.4% (99.2-99.6%), respectively. Cryptococcal cells were found in 22.07% of blood samples. Conclusion: This high-speed microscopy system can analyze fungal pathogens in blood samples rapidly with high sensitivity and specificity and can help dramatically accelerate the diagnosis of fungal infectious diseases.

Acute kidney injury should not be neglected - optimization of quick Pitt bacteremia score for predicting mortality in critically ill patients with bloodstream infection: a retrospective cohort study

Background

Considering the therapeutic difficulties and mortality associated with bloodstream infection (BSI), it is essential to investigate other potential factors affecting mortality in critically ill patients with BSI and examine the utility of the quick Pitt bacteremia (qPitt) score to improve the survival rate.

Objectives

To improve the predictive accuracy of the qPitt scoring system by evaluating the five current components of qPitt and including other potential factors influencing mortality in critically ill patients with BSI.

Design

This was a retrospective cohort study.

Methods

Medical information from the Medical Information Mart for Intensive Care IV database was used in this retrospective cohort study. The risk factors associated with mortality were examined using a multivariate logistic regression model. The area under the receiver operating characteristic curve (AUC) was used to assess the discriminatory capability of the prediction models.

Results

In total, 1240 eligible critically ill patients with BSI were included. After adjustment for age, community-onset BSI, indwelling invasive lines, and Glasgow Coma Scale (GCS) ⩽ 8, acute kidney injury (AKI) was identified as a notable risk factor for 14-day mortality. Except for altered mental status, the four other main components of the original qPitt were significantly associated with 14-day mortality. Hence, we established a modified qPitt (m-qPitt) by adding AKI and replacing altered mental status with GCS ⩽ 8. The AUCs for m-qPitt and qPitt were 0.723 [95% confidence interval (CI): 0.683-0.759] and 0.708 (95% CI: 0.669-0.745) in predicting 14-day mortality, respectively. Moreover, m-qPitt also had acceptable performance and discrimination power [0.700 (95% CI: 0.666-0.732)] in predicting 28-day mortality.

Conclusion

AKI significantly influenced the survival of critically ill patients with BSIs. Compared with the original qPitt, our new m-qPitt was proven to have a better predictive performance for mortality in critically ill patients with BSI. Further studies should be conducted to validate the practicality of m-qPitt.

Potential impact of real-time processing and rapid susceptibility testing of blood samples in Gram-negative bloodstream infections in intensive care patients

INTRODUCTION

Timely and appropriate therapy is critical in patients with Gram-negative bloodstream infections (GNBSI). Most bacteriology laboratories process blood specimen in the daytime, during laboratory operating hours, and use conventional culture for antimicrobial susceptibility testing (AST). We simulated the potential impact of real-time processing and rapid AST (7 hours) on early adaptation of the antibiotic regimen in intensive care unit (ICU) patients with GNBSI.

METHODS

All GNBSI episodes occurring in the ICUs of 2 hospitals in Paris were included. Data were collected. For each episode of bacteremia, we simulated the impact of three strategies: (1) Real-time processing coupled with conventional techniques (Gram stain and standard AST); (2) Standard processing coupled with rapid AST; and (3) Real-time processing coupled with rapid AST.

RESULTS

We included 109 episodes in 98 patients. Forty-two patients (48%) died during ICU stay. AST results led to a change of the antibiotic regimen in 66 (61%) episodes, mainly de-escalation (54/109, 55%). In standard care, median time from sample collection to definitive AST result was 65.9 hours (±26.7). The three strategies would have reduced time-to-result by 9.2 hours (±7.1), 30.8 hours (±19.7) and 40.0 hours (±20.6) respectively. Compared to standard care, strategies 1, 2 and 3 would have avoided 20, 69 and 90 patient-days of broad-spectrum antibiotics respectively.

CONCLUSION

In addition to real-time processing of blood samples, rapid AST would be the most effective strategy to shorten time-to-result in critical patients with GNBSI.

A review of Spaulding's classification system for effective cleaning, disinfection and sterilization of reusable medical devices: Viewed through a modern-day lens that will inform and enable future sustainability

Despite advances in medicine and innovations in many underpinning fields including disease prevention and control, the Spaulding classification system, originally proposed in 1957, remains widely used for defining the disinfection and sterilization of contaminated re-usable medical devices and surgical instruments. Screening PubMed and Scopus databases using a PRISMA guiding framework generated 272 relevant publications that were used in this review. Findings revealed that there is a need to evolve how medical devices are designed, and processed by cleaning, disinfection (and/or sterilization) to mitigate patient risks, including acquiring an infection. This Spaulding Classification remains in use as it is logical, easily applied and understood by users (microbiologists, epidemiologists, manufacturers, industry) and by regulators. However, substantial changes have occurred over the past 65 years that challenge interpretation and application of this system that includes inter alia emergence of new pathogens (viruses, mycobacteria, protozoa, fungi), a greater understanding of innate and adaptive microbial tolerance to disinfection, toxicity risks, increased number of vulnerable patients and associated patient procedures, and greater complexity in design and use of medical devices. Common cited examples include endoscopes that enable non- or minimal invasive procedures but are highly sophisticated with various types of materials (polymers, electronic components etc), long narrow channels, right angle and heat-sensitive components and various accessories (e.g., values) that can be contaminated with high levels of microbial bioburden and patient tissues after use. Contaminated flexible duodenoscopes have been a source of several significant infection outbreaks, where at least 9 reported cases were caused by multidrug resistant organisms [MDROs] with no obvious breach in processing detected. Despite this, there is evidence of the lack of attention to cleaning and maintenance of these devices and associated equipment. Over the last few decades there is increasing genomic evidence of innate and adaptive resistance to chemical disinfectant methods along with adaptive tolerance to environmental stresses. To reduce these risks, it has been proposed to elevate classification of higher-risk flexible endoscopes (such as duodenoscopes) from semi-critical [contact with mucous membrane and intact skin] to critical use [contact with sterile tissue and blood] that entails a transition to using low-temperature sterilization modalities instead of routinely using high-level disinfection; thus, increasing the margin of safety for endoscope processing. This timely review addresses important issues surrounding use of the Spaulding classification system to meet modern-day needs. It specifically addresses the need for automated, robust cleaning and drying methods combined with using real-time monitoring of device processing. There is a need to understand entire end-to-end processing of devices instead of adopting silo approaches that in the future will be informed by artificial intelligence and deep-learning/machine learning. For example, combinational solutions that address the formation of complex biofilms that harbour pathogenic and opportunistic microorganisms on the surfaces of processed devices. Emerging trends are addressed including future sustainability for the medical devices sector that can be enabled via a new Quintuple Helix Hub approach that combines academia, industry, healthcare, regulators, and society to unlock real world solutions.

Potential of metagenomic next-generation sequencing in detecting infections of ICU patients

BACKGROUND

Due to the limitations of traditional microbiological detection techniques in evaluating complicated infections in ICU patients, it is necessary to explore novel and effective methods to improve the clinical detection of ICU patients' infections.

OBJECTIVE

This study aimed to evaluate the efficiency and specificity of mNGS in screening pathogens in the blood, deep phlegm, urine, and other sample types of ICU patients exploring an effective method for infection detection.

METHODS

A total of 56 ICU patients with 131 samples were included in this study. The sample types included blood, deep phlegm, urine, drainage, anal swabs, and other types. Samples were analyzed by both conventional detection method and mNGS tests. The diagnosis efficiency and consistency of the two methods were compared. The distribution of the identified pathogens was analyzed. Moreover, the clinical features of patients with mNGS-positive or mNGS-negative results were compared.

RESULTS

The positive rate of mNGS was 81.7% (107/131) including 3.1% (4/131) weakly positive, while the positive rate of traditional detection was only 30.5%, including 29 strong positive results and 11 weak positive results. Additionally, there were 41 patients chose to adjust anti-infection strategies according to the results of mNGS, which significantly saved treatment costs. The mNGS-positive patients showed a shorter ICU hospitalization and higher intention to adjust anti-infection strategies than the mNGS-negative patients.

CONCLUSION

mNGS is of great potential for the pathogen detection of ICU patients, and has a higher detection rate than traditional detection methods. Further clinical application investigations can be carried out to expand the application of mNGS.

Correlation of procalcitonin to positive blood culture results in a sample of South African trauma ICU patients between 2016 and 2017

PURPOSE

This study sought to investigate the screening accuracy of procalcitonin (PCT) for bacteremia, as defined by a positive blood culture, in a South African trauma ICU.

METHODS

This was a retrospective chart review study involving 149 patients who were admitted to the ICU of a level-1 trauma center in South Africa between 2016 and 2017. Median PCT levels in patients with and without positive blood cultures were compared. The screening accuracy of PCT for a positive blood culture was summarized as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Two PCT cut-points were investigated: a general cut-point in the South African context (> 2.0 ng/mL), and a trauma ICU-specific cut-point (prioritizing specificity while optimizing sensitivity) which was determined from a receiver-operator-characteristic curve.

RESULTS

Bacteremic patients had higher median PCT levels when compared with non-bacteremic patients (30.5 ng/mL versus 6.6 ng/mL, p = 0.002). The sensitivity, specificity, PPV, and NPV of PCT > 2.0 ng/mL was 86% (95% confidence interval-CI 71-94%), 29% (CI 22-38%), 28% (CI 20-37%), and 87% (CI 73-94%), respectively. The unit-specific cut-point was PCT > 31.0 ng/mL, which had a sensitivity, specificity, PPV, and NPV of 50% (CI 34-66%), 80% (CI 71-86%), 44% (CI 30-59%), and 83% (CI 75-89%), respectively. Unlike PCT > 2.0 ng/mL, PCT > 31.0 ng/mL demonstrated fair-to-good test specificity in a sub-analysis of patients who underwent recent surgery.

CONCLUSIONS

Increased PCT levels were associated with bacteremia in this study. PCT > 31.0 ng/mL may be used to rule in suspected bacteremia in this trauma ICU setting.

Chlorhexidine gluconate transparent dressing does not decrease central line‐associated bloodstream infection in critically ill patients: A randomized controlled trial

Background

Central line‐associated blood stream infections are accompanied by increased mortality and health care costs. The application of different types of dressings in infection control has not been fully investigated to date.

Aim

To assess the effects of two different dressing types on central line‐associated bloodstream infections.

Methods

A randomized, nonblinded, controlled trial was conducted. Central lines were randomly allocated to intervention (chlorhexidine gluconate transparent dressing, n = 259) and control groups (standard dressing, n = 215). The central line‐associated bloodstream infection rate was assessed.

Results

A statistically nonsignificant difference was noted in the overall central line‐associated bloodstream infection rates between the two groups. The frequency of dressing changes in the patients with the chlorhexidine gluconate transparent dressing was significantly lower than that in the patients with a standard dressing. The predominant type of infectious microorganisms isolated from the central line‐associated bloodstream infection episodes was Gram‐negative bacteria (57.2%). Gram‐positive bacteria and fungi were noted at lower percentages (28.5% and 14.3%, respectively).

Conclusion

The use of a chlorhexidine gluconate transparent dressing does not decrease the central line‐associated bloodstream infection rate, although it decreases the frequency of dressing changes so may save nursing time.

What is already known about this topic?

The use of a chlorhexidine gluconate transparent dressing has been reported to significantly reduce central line‐associated bloodstream infections or maintain low central line‐associated bloodstream infections in Western countries, but few studies have been carried out in Asian countries.

The chlorhexidine dressing does not decrease central line‐associated bloodstream infections due to the presence of Gram‐negative bacteria.

It has been reported that nurses prefer the chlorhexidine gluconate transparent dressing over the standard dressing.

What this paper adds?

Compared with the standard dressing, the chlorhexidine gluconate transparent dressing does not significantly decrease the central line‐associated bloodstream infection rate.

The predominant infectious microorganisms isolated from central line-associated bloodstream infections episodes were Gram-negative bacteria.

The cost of the chlorhexidine gluconate transparent dressing was significantly higher than that of the standard dressing, although the former could save nursing time due to the decreased frequency of dressing changes.

The implications of this paper are as follows:

The use of chlorhexidine gluconate transparent dressing does not offer any additional benefit in controlling infection.

Further studies are required to identify ways to control the colonization or infection of Gram‐negative bacteria in patients because Gram‐negative bacteria are the predominant infectious microorganisms that cause central line‐associated bloodstream infection.

The use of a chlorhexidine gluconate transparent dressing is proposed as an alternative choice that can reduce ICU nursing time in hospital settings and therefore should be considered by nursing managers for human resource cost control.

Hydrogen peroxide and sodium hypochlorite disinfectants are more effective against Staphylococcus aureus and Pseudomonas aeruginosa biofilms than quaternary ammonium compounds

Background

Antimicrobial disinfectants are used as primary treatment options against pathogens on surfaces in healthcare facilities to help prevent healthcare associated infections (HAIs). On many surfaces, pathogenic microorganisms exist as biofilms and form an extracellular matrix that protects them from the antimicrobial effects of disinfectants. Disinfectants are used as all-purpose antimicrobials though very few specifically make biofilm efficacy claims. The objective of this study was to evaluate the efficacy of eight registered disinfectants (six registered by the Environmental Protection Agency and two products registered in by the European Chemical Agency) with general bactericidal claims, but currently no biofilm efficacy claims, against Staphylococcus aureus ATTC-6538 and Pseudomonas aeruginosa ATCC-15442 biofilms. We hypothesized that hydrogen peroxide and sodium hypochlorite disinfectant products would be more effective than quaternary ammonium chlorides.

Methods

This study tested the bactericidal efficacy of eight registered disinfectant products against S. aureus ATCC-6538 and P. aeruginosa ATCC-15442 grown on glass coupons using a Center for Disease Control (CDC) biofilm reactor and EPA MLB SOP MB-19. Bactericidal efficacy was determined after treating coupons with disinfectants following standard EPA MLB SOP MB-20.

Results

Overall, sodium hypochlorite and hydrogen peroxide disinfectants had significantly higher bactericidal efficacies than quaternary ammonium chloride disinfectants. We also found that all tested disinfectants except for quaternary ammonium chloride disinfectants met and exceeded the EPA standard for bactericidal efficacy against biofilms.

Conclusion

In general, bactericidal efficacy against biofilms differed by active ingredient. The efficacies of sodium hypochlorite and hydrogen peroxide disinfectants did not vary between strains, but there were significant differences between strains treated with quaternary ammonium chloride disinfectants.

Bacterial Distribution and Risk Factors of Nosocomial Blood Stream Infection in Neurologic Patients in the Intensive Care Unit

OBJECTIVE

To investigate the risk factors and analyze the distribution of pathogens to provide a basis for the prevention of nosocomial blood stream infections (BSI) and reduce the incidence and mortality of nosocomial BSI in neurologic patients.

PATIENTS AND METHODS

A retrospective chart review of neurologic patients admitted to an adult intensive care unit from January 2012 to December 2017 was conducted. Every positive blood culture, clinical demographic, microbiologic and laboratory result, as well as 28-day outcome data, were compiled on a data collection sheet. The clinical significance of each isolate was determined; in addition, the antimicrobial susceptibilities of causative pathogens and the most likely source were recorded.

RESULTS

During the five-year study period, there were 121 nosocomial BSI yielding 151 isolates in 404 neurologic patients. Eighty-one percent of nosocomial BSI were monomicrobial. Gram-positive organisms caused 67.9% of these BSI, gram-negative organisms caused 32.1%, and fungi caused 0.8%. The crude incidence rate was approximately 29.9%, and the mortality of nosocomial BSI was as high as 29.8%. Intravascular lines were the most common source of nosocomial BSI (79.3%). The most common organisms causing BSI were coagulase-negative staphylococci (CoNS; 44.6% of isolates), Staphylococcus aureus (17.4%), Klebsiella species (11.5%), and Acinetobacter spp. (11.5%). Multivariable regression analysis revealed that the use of antibiotic agents in the 90 days prior (odds ratio [OR], 5.81; 95% confidence interval [CI], 3.18-10.62; p = 0.001), brain trauma (OR, 0.28; 95% CI, 0.15-0.51; p = 0.001), and transfusion (OR, 3.02; 95% CI, 1.45-6.29; p = 0.001) were significant predictors of nosocomial BSI.

CONCLUSIONS

The incidence and mortality of nosocomial BSI were high in our neurologic patients. Strictly aseptic operations, hand hygiene, and reasonable use of transfusions and antibiotic agents are effective measures to prevent nosocomial BSI.

Bloodstream infections in NNICU: Blight on ICU stay

Background:

Bloodstream infections (BSIs) are among the serious hospital-acquired infections. Data regarding BSIs in intensive care units (ICUs) are available but there is limited information regarding these infections in neurology and neurosurgery intensive care units (NNICUs).

Objectives:

This study was conducted to find out the occurrence of BSI in NNICU patients of a tertiary care institute in India, along with the microbiological profile and risk factors associated with it.

Materials and Methods:

One hundred patients admitted in the NNICU of a tertiary care hospital for more than 24 h were included in the study. After detailed history, blood samples were collected from catheter hub and peripheral vein of all patients for culture, followed by identification and antibiotic sensitivity testing of the isolates.

Results:

Out of 100 patients, laboratory-confirmed bloodstream infection (LCBI) was detected in 16 patients. Five patients had secondary BSI, while 11 had central venous catheter (CVC)-related primary BSI. Gram-positive organisms constituted 64% of the isolates, especially coagulase-negative staphylococci and Staphylococcus aureus. Increased duration of CVC was a significant risk factor for catheter-related BSI (CR-BSI).

Conclusion:

BSIs pose a significant burden for NNICU patients, and increased duration of catheter insertion is a significant risk factor for CR-BSI.

Inverting the pyramid: increasing awareness of mycobacterial sepsis in sub-Saharan Africa

Disseminated Mycobacterium tuberculosis is a leading cause of bloodstream infection and severe sepsis in sub-Saharan African settings with a high burden of tuberculosis (TB) and human immunodeficiency virus (HIV) infection. Despite the high prevalence of M. tuberculosis bacteremia in these settings it is under-recognized. This is in part because timely diagnosis of M. tuberculosis bacteremia is difficult using traditional TB diagnostics. Novel triage algorithms and rapid diagnostic tests are needed to expedite the identification and treatment of patients with severe sepsis due to M. tuberculosis bacteremia. In this article, we emphasize the importance of M. tuberculosis bacteremia as an under-recognized etiology of severe sepsis, and discuss the potential role of two emerging rapid diagnostic tests in the triage and prognostication of critically ill patients with advanced HIV infection and suspected disseminated M. tuberculosis. We conclude with the recommendation that clinicians in high TB-HIV burden settings strongly consider empiric anti-tuberculosis treatment in patients with advanced HIV infection and severe sepsis in the appropriate clinical context. Future studies are needed to assess diagnostic and prognostic algorithms for severe sepsis caused by disseminated M. tuberculosis in these settings, and the safety, efficacy, and duration of empiric anti-tuberculosis treatment.

Ribosomal RNA-based panbacterial polymerase chain reaction for rapid diagnosis of septicaemia in Intensive Care Unit patients

Early diagnosis and treatment of sepsis by appropriate antibiotics is of utmost importance. Therefore, we evaluated 16S rRNA panbacterial polymerase chain reaction (PCR) for rapid diagnosis of sepsis in 49 adult patients in Intensive Care Units (ICUs) and compared it with an automated blood culture. 8 ml of 10 ml blood collected was inoculated into BACTEC® aerobic bottle and the remaining 2 ml was used for DNA extraction and PCR. 109 of 115 (93%) episodes of suspected sepsis showed concordant results between automated culture and PCR. Six episodes were positive by PCR only. Panbacterial PCR reduces turnaround time with rapid differentiation between systemic inflammatory response syndrome and sepsis.

Custos com antimicrobianos no tratamento de pacientes com infecção

<p>Os custos relacionados ao tratamento antimicrobiano de pacientes com infecções da corrente sanguínea causadas por microrganismos resistentes têm sido pouco explorados. Objetivo: Comparar os custos diretos do tratamento antimicrobiano de pacientes com infecção da corrente sanguínea causada por Staphylococcus aureus resistente e sensível à oxacilina (MRSA e MSSA, respectivamente). Metodologia: Tratou-se de uma coorte histórica, realizada em uma unidade de terapia intensiva. Foram incluídos pacientes com infecção da corrente sanguínea por Staphylococcus aureus, entre março de 2007 e março de 2011. Utilizaram-se os registros dos prontuários, da comissão de controle de infecção hospitalar e do sistema de finanças do hospital, sendo realizada análise univariada. Resultados: Fizeram parte do estudo 31 pacientes tanto no grupo infectado por MRSA, quanto naquele infectado por MSSA. De acordo com a análise univariada, o direcionamento do tratamento reduziu o espectro de ação dos antibióticos utilizados e os custos (0,001) e a resistência bacteriana esteve relacionada a um maior gasto com o tratamento antimicrobiano empírico (= 0,05), não sendo encontrada associação para tratamentos direcionado e total. Conclusão: A resistência bacteriana pode influenciar os custos com tratamento antimicrobiano, sendo necessários mais estudos sobre o tema, avaliando especificamente tratamento antimicrobiano.</p>

Microbiologic characteristics and predictors of mortality in bloodstream infections in intensive care unit patients: A 1-year, large, prospective surveillance study in 5 Italian hospitals

BACKGROUND

Bloodstream infections (BSIs) from multidrug-resistant (MDR) bacteria cause morbidity and mortality in intensive care unit (ICU) patients worldwide. This study investigated the incidence of BSIs in 5 adult general ICUs in Rome, Italy, and evaluated the mortality rate and risk factors associated with these infections.

METHODS

Over a 12-month period, 1,318 patients were enrolled. Demographic characteristics, Simplified Acute Physiology Score II (SAPS II), comorbidities, and BSI isolate data were collected. After stratification for the outcome, statistical analysis was performed to assess the impact of patient risk factors on in-hospital mortality.

RESULTS

There were 324 BSIs in 175 patients recorded, with an in-hospital mortality rate of 46%. Univariate analysis revealed that SAPS II, cardiac comorbidity, and Klebsiella pneumoniae BSI were significantly associated with a higher risk of death. Having a K pneumoniae BSI and cardiac illness at admission were both confirmed to be associated with death by multivariate analysis (P = .0162 and P = .0158, respectively). Most of the K pneumoniae isolates showed high resistance rates to carbapenems.

CONCLUSION

BSIs caused by K pneumoniae and cardiovascular comorbidity in ICU patients are associated with a higher risk of death. Thorough surveillance for MDR pathogens and stratification of the patients' risk on admission into the ICU are key to improving the outcomes of these infections.

Potent bactericidal efficacy of copper oxide impregnated non-porous solid surfaces

BACKGROUND

The role of fomites and the environment in nosocomial infections is becoming widely recognized. In this paper we discuss the use of Cupron copper oxide impregnated non-porous solid surface in the hospital setting and present in vitro testing data via USA Environmental Protection Agency (EPA) approved testing protocols that demonstrate the efficacy of these products to assist in reduction in environmental contamination and potentially nosocomial infections.

RESULTS

The two countertops tested passed all the acceptance criteria by the EPA (>99.9% kill within 2 hours of exposure) killing a range of bacterial pathogens on the surface of the countertops even after repeated exposure of the countertops to the pathogen, and multiple wet and dry abrasion cycles.

CONCLUSIONS

Cupron enhanced EOS countertops thus may be an important adjunct to be used in hospital settings to reduce environmental bioburden and potentially nosocomial infections.

Ecology of blood stream infection and antibiotic resistance in intensive care unit at a tertiary care hospital in North India

Objective

To analyse the prevalent microorganisms and their antimicrobial resistance among intensive care unit patients in a tertiary care centre in New Delhi.

Methods

A retrospective study of all consecutive blood cultures from various intensive care unit patients in the hospital during four years (January 2008 to December 2011). Antibiotic consumption data in the intensive care units were also analysed during the same period.

Results

Out of the total 22,491 blood cultures processed, 2846 samples were positive and 3771 microorganisms were isolated. The blood culture positivity was estimated as 12.7% of which 67.5% were monomicrobial and 32.5% polymicrobial infections. Gram negative bacilli, Gram positive cocci, and fungi were isolated in 49%, 33%, and 18% cases, respectively. Coagulase negative staphylococcus was the commonest single isolate followed by Candida spp. A drastic shift in the distribution of Candida spp. towards nonalbicans along with high resistance to azole group of antifungals suggest echinocandins for the empiric therapy of candidemia. High penicillin resistance in Gram positive isolates suggest vancomycin, linezolid and tigecycline as the options for empiric therapy, whereas tigecycline and colistin are the only options remaining for highly resistant Gram negative isolates. Aminoglycosides were observed to have better sensitivity and reduced usage when compared with cephalosporins and β-lactam + β-lactam inhibitor combinations.

Conclusions

High frequencies of multidrug resistant organisms were observed in intensive care units which is a warning as to use the only few effective antimicrobials wisely to reduce selective pressure on sensitive strains.

Infections acquired in intensive care units: results of national surveillance in Belgium, 1997-2010

BACKGROUND AND AIM

To describe the methodology and output of the Belgian surveillance for infections acquired in intensive care units (ICUs) between 1997 and 2010.

METHODS

Since 1997, ICUs in acute care hospitals in Belgium have been encouraged by federal law to participate in a national multi-centre prospective observational surveillance programme. A protocol and software tool for data collection was developed, and the case definitions and methodology follow those of the European Centre for Disease Prevention and Control.

FINDINGS

For 2010, 18 hospitals provided data on 59 observation quarters, 6478 ICU patients and 52,593 ICU patient-days. The mean incidence rates of ICU-acquired pneumonia and intubation-associated pneumonia were 13 per 1000 patient-days and 12 per 1000 intubation-days, respectively. The mean incidence rates of ICU-acquired bloodstream infections, central vascular catheter (CVC)-associated bloodstream infections and CVC-associated primary bloodstream infections were 3.2 per 1000 patient-days, 2.6 per 1000 catheter-days and 2.3 per 1000 catheter-days, respectively. Between 1997 and 2010, stable trends in ICU-acquired pneumonia and bloodstream infections were observed, together with decreasing trends for intubation-associated pneumonia and CVC-associated bloodstream infections, and a stable trend for CVC-associated primary bloodstream infections.

CONCLUSIONS

In Belgium, national surveillance of ICU-acquired infections allows acute care hospitals to track the incidence of infections at local level, enabling comparison with national and European reference data. Between 1997 and 2010, the incidence of ICU-acquired infections increased and the incidence of device-associated infections decreased.

Fighting nosocomial infections with biocidal non-intrusive hard and soft surfaces

Approximately 7 million people worldwide acquire a healthcare associated infection each year. Despite aggressive monitoring, hand washing campaigns and other infection control measures, nosocomial infections (NI) rates, especially those caused by antibiotic resistant pathogens, are unacceptably high worldwide. Additional ways to fight these infections need to be developed. A potential overlooked and neglected source of nosocomial pathogens are those found in non-intrusive soft and hard surfaces located in clinical settings. Soft surfaces, such as patient pyjamas and beddings, can be an excellent substrate for bacterial and fungal growth under appropriate temperature and humidity conditions as those present between patients and the bed. Bed making in hospitals releases large quantities of microorganisms into the air, which contaminate the immediate and non-immediate surroundings. Microbes can survive on hard surfaces, such as metal trays, bed rails and door knobs, for very prolonged periods of time. Thus soft and hard surfaces that are in direct or indirect contact with the patients can serve as a source of nosocomial pathogens. Recently it has been demonstrated that copper surfaces and copper oxide containing textiles have potent intrinsic biocidal properties. This manuscript reviews the recent laboratory and clinical studies, which demonstrate that biocidal surfaces made of copper or containing copper can reduce the microbiological burden and the NI rates.

Clinical characteristics and outcome of patients with community-onset Klebsiella pneumoniae bacteremia requiring intensive care

BACKGROUND

Klebsiella pneumoniae (K. pneumoniae) is the major pathogen of community-acquired pyogenic infections in Taiwan and can lead to poor prognosis in critically ill patients complicated with bacteremia. This study investigated the characteristics and outcome of patients with community-onset K. pneumoniae bacteremia who required intensive care.

METHOD

Adult patients with community-onset K. pneumoniae bacteremia requiring intensive care were retrospectively analyzed, compared with those treated in ordinary wards, and determined for risk factors for infection-related mortality and long-term mortality at a medical center in Taiwan over a 3-year period.

RESULTS

Among the 309 patients with community-onset K. pneumoniae bacteremia, 58 patients (18.8%) required intensive care. Respiratory tract infection [Odds ratio (OR) = 3.67, 95% confidence interval (CI) = 1.79-7.50, p < 0.001] was the independent risk factor for ICU admission. Infection-related mortality was 34.5%. Higher APACHE II score (OR = 1.43; 95% CI = 1.02-2.01; p = 0.041) and underlying malignant neoplasm (OR = 35.48; 95% CI = 2.54-495.57; p = 0.008) were independent predictors of infection-related mortality on multivariate logistic regression. One-year overall mortality was 58.6% and malignant neoplasm was the predisposing factor for poor long-term outcome.

CONCLUSION

Nearly one fifth of patients with community-onset K. pneumoniae bacteremia required intensive care and this was associated with high mortality and poor long-term prognosis. Physicians should recognize the distinct characteristics and risk factors for mortality among these patients.

Antimicrobial de-escalation strategies in hospitalized patients with pneumonia, intra-abdominal infections, and bacteremia

Increasing numbers of serious hospital/healthcare- or community-acquired infections are caused by resistant (often multi-drug resistant) bacterial pathogens. Because delayed or ineffective initial therapy can have severe negative consequences, patients at risk for these types of infections typically receive initial empiric antibiotic therapy with a broad-spectrum regimen covering the most likely pathogens, based on local surveillance data and risk factors for infection with a resistant microorganism. While improving the likelihood of a successful outcome, use of broad-spectrum, often high-dose, empiric antimicrobial therapy also creates pressure for the selection or development of resistant microorganisms, as well as increasing costs and possibly exposing patients to adverse events or collateral damage such as Clostridium difficile-associated disease. De-escalation is a strategy that attempts to balance the competing aims of providing initial empiric therapy that is appropriate and covers the likely pathogens, and limiting antimicrobial exposure and increased risk for emergence of resistant pathogens. More specifically, the de-escalation strategy involves collection of cultures for later microbiological assessment before initiating broad-spectrum empiric therapy covering the most likely pathogens, with the intention of streamlining or de-escalating to a more narrow-spectrum antimicrobial regimen 2-3 days later if warranted by clinical status and culture results. In some cases, negative culture results and subsequent clinical review may allow for termination of initial empiric therapy. In this manner, de-escalation enables more effective targeting of the causative pathogen(s), elimination of redundant therapy, a decrease in antimicrobial pressure for emergence of resistance, and cost savings. This article examines application of the de-escalation strategy to 3 case patients, one with healthcare-associated pneumonia, another with complicated intra-abdominal infection, and a third with central line-associated bacteremia.

Prevalence and epidemiology of microbial pathogens causing bloodstream infections: results of the OASIS multicenter study

Beginning on April 2007, a prospective multicenter study was performed to investigate prevalence and epidemiology of microbial pathogens causing bloodstream infections (BSIs). Twenty microbiology laboratories participated to the survey over a 1-year period. A total of 11,638 episodes of BSI occurred in 11 202 patients, with 8.5% (n=985) of episodes being polymicrobial. Of 12 781 causative organisms, aerobic Gram-negative bacteria were 47.4% (n=6058), whereas Gram-positives accounted for 43.9% (n=5608). The remaining organisms included fungal species (n=924, 7.2%) and anaerobes (n=191, 1.5%). The most prevalent agents were Escherichia coli (21.7%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (8.2%), Pseudomonas aeruginosa (7.0%), and Enterococcus faecalis (6.3%). Isolates recovered from patients admitted to medical, surgical, and intensive care units accounted for 62.9%, 17.7%, and 19.4% of cases, respectively. BSIs were classified as hospital-acquired in 67.2% of cases. Compared with previous studies, our data show an increasing role of Gram-negative bacteria among both hospital- and community-acquired blood isolates.

Bacterial resistance and mortality in an intensive care unit

The goal was to identify risk factors for healthcare-associated infections by resistant microorganisms and patient mortality in an Intensive Care Unit. A prospective and descriptive epidemiological research was conducted from 2005 till 2008, involving 2300 patients. Descriptive statistics, bivariate and multivariate logistic regression analysis were used. In bivariate analysis, infection caused by resistant microorganism was significantly associated to patients with community-acquired infection (p=0.03; OR=1.79) and colonization by resistant microorganism (p<0.01; OR=14.22). In multivariate analysis, clinical severity (p=0.03; OR=0.25) and colonization by resistant microorganism (p<0.01; OR=21.73) were significant. Mortality was associated to the following risk factors: type of patient, average severity index, besides mechanical ventilation. The relation between resistant microorganisms and death shows the need to monitor adherence to infection control measures so as to improve care quality and mainly survival of critical patients.

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.

Acquired bloodstream infection in the intensive care unit: incidence and attributable mortality

INTRODUCTION

To estimate the incidence of intensive care unit (ICU)-acquired bloodstream infection (BSI) and its independent effect on hospital mortality.

METHODS

We retrospectively studied acquisition of BSI during admissions of >72 hours to adult ICUs from two university-affiliated hospitals. We obtained demographics, illness severity and co-morbidity data from ICU databases and microbiological diagnoses from departmental electronic records. We assessed survival at hospital discharge or at 90 days if still hospitalized.

RESULTS

We identified 6339 ICU admissions, 330 of which were complicated by BSI (5.2%). Median time to first positive culture was 7 days (IQR 5-12). Overall mortality was 23.5%, 41.2% in patients with BSI and 22.5% in those without. Patients who developed BSI had higher illness severity at ICU admission (median APACHE III score: 79 vs. 68, P < 0.001). After controlling for illness severity and baseline demographics by Cox proportional-hazard model, BSI remained independently associated with risk of death (hazard ratio from diagnosis 2.89; 95% confidence interval 2.41-3.46; P < 0.001). However, only 5% of the deaths in this model could be attributed to acquired-BSI, equivalent to an absolute decrease in survival of 1% of the total population. When analyzed by microbiological classification, Candida, Staphylococcus aureus and gram-negative bacilli infections were independently associated with increased risk of death. In a sub-group analysis intravascular catheter associated BSI remained associated with significant risk of death (hazard ratio 2.64; 95% confidence interval 1.44-4.83; P = 0.002).

CONCLUSIONS

ICU-acquired BSI is associated with greater in-hospital mortality, but complicates only 5% of ICU admissions and its absolute effect on population mortality is limited. These findings have implications for the design and interpretation of clinical trials.

Antimicrobial resistance of bacterial isolates from respiratory care wards in Taiwan: a horizontal surveillance study comparison of the characteristics of nosocomial infection and antimicrobial-resistant bacteria in adult Intensive Care Units and two respiratory care facilities for mechanically ventilated patients at a tertiary care centre in Taiwan

The objectives of this study were to compare the incidence of nosocomial infections (NIs) and the distribution of resistant nosocomial pathogens in adult Intensive Care Units (ICUs) and two respiratory care facilities for prolonged mechanically ventilated patients [i.e. the respiratory care centre (RCC) and the respiratory care ward (RCW)] in a 1100-bed tertiary care hospital in Taiwan from 2003 to 2006. The overall incidences of NI for adult ICUs, the RCC and the RCW were 14.0, 10.3 and 5.0 per 1000 patient-days, respectively. Urinary tract infections, bloodstream infections and pneumonias occurred most frequently. The most common reported microorganisms in adult ICUs were non-fermentative Gram-negative bacilli (NFGNB) (33.0%), Enterobacteriaceae (26.5%), Candida spp. (18.2%), Staphylococcus aureus (8.9%), coagulase-negative staphylococci (CoNS) (4.9%) and enterococci (4.5%). In comparison, RCW patients had a higher proportion of NIs caused by S. aureus [odds ratio (OR)=1.9], enterococci (OR=2.2) and Enterobacteriaceae (OR=2.2), but a lower proportion of CoNS (OR=0.3), NFGNB (OR=0.5) and Candida spp. (OR=0.2). RCW patients had higher incidence rates of methicillin-resistant S. aureus (OR=4.91) and extended-spectrum β-lactamase-producing Enterobacteriaceae (OR=4.06) than ICU patients. Further study is needed to delineate the mechanisms responsible for the differences in resistance profile amongst pathogens associated with nosocomial infection in ICUs, RCCs and RCWs.