Risk factors and outcomes of infections caused by extremely drug-resistant gram-negative bacilli in patients hospitalized in intensive care units

The Global Burden of Sepsis and Septic Shock

A dysregulated host response to infection causes organ dysfunction in sepsis and septic shock, two potentially fatal diseases. They continue to be major worldwide health burdens with high rates of morbidity and mortality despite advancements in medical care. The goal of this thorough review was to present a thorough summary of the current body of knowledge about the prevalence of sepsis and septic shock worldwide. Using widely used computerized databases, a comprehensive search of the literature was carried out, and relevant studies were chosen in accordance with predetermined inclusion and exclusion criteria. A narrative technique was used to synthesize the data that were retrieved. The review's conclusions show how widely different locations and nations differ in terms of sepsis and septic shock's incidence, prevalence, and fatality rates. Compared to high-income countries (HICs), low- and middle-income countries (LMICs) are disproportionately burdened more heavily. We talk about risk factors, comorbidities, and difficulties in clinical management and diagnosis in a range of healthcare settings. The review highlights the need for more research, enhanced awareness, and context-specific interventions in order to successfully address the global burden of sepsis and septic shock.

Impact of Immunosuppressed Status on Prognosis of Carbapenem-Resistant Organisms Bloodstream Infections

INTRODUCTION

The impact of immunosuppression on prognosis of carbapenem-resistant organism (CRO) bloodstream infection (BSI) remains unclear. The aim of this study was to clarify the relationship between immunosuppression and mortality of CRO-BSI and to identify the risk factors associated with mortality in immunosuppressed patients.

METHODS

This retrospective study included 279 patients with CRO-BSI from January 2018 to March 2023. Clinical characteristics and outcomes were compared between the immunosuppressed and immunocompetent patients. The relationship between immunosuppression and 30-day mortality after BSI onset was assessed through logistic-regression analysis, propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). Factors associated with mortality in immunosuppressed patients were analyzed using multivariable logistic regression analysis.

RESULTS

A total of 88 immunocompetent and 191 immunosuppressed patients were included, with 30-day all-cause mortality of 58.8%. Although the 30-day mortality in immunosuppressed patients was significantly higher than in immunocompetent patients (46.6% vs. 64.4%, P = 0.007), immunosuppression was not an independent risk factor for mortality in multivariate logistic regression analysis (odds ratio [OR] 3.53, 95% confidence interval [CI] 0.74-18.89; P = 0.123), PSM (OR 1.38, 95% CI 0.60-3.18; P = 0.449,) or IPTW (OR 1.40, 95% CI 0.58-3.36; P = 0.447). For patients with CRO-BSI, regardless of immune status, appropriate antibiotic therapy was associated with decreased 30-day mortality, while Charlson comorbidity index (CCI), intensive care unit (ICU)-acquired infection and thrombocytopenia at CRO-BSI onset were associated with increased mortality.

CONCLUSION

Despite the high mortality rate of CRO-BSI, immunosuppression did not affect the mortality. Appropriate antibiotic therapy is crucial for improving the prognosis of CRO-BSI, regardless of the immune status.

Antibiogram Profile and Detection of Resistance Genes in Pseudomonas aeruginosa Recovered from Hospital Wastewater Effluent

The nosocomial pathogen Pseudomonas aeruginosa (P. aeruginosa) is characterized by increased prevalence in hospital wastewater and is a public health concern. Untreated wastewater severely challenges human health when discharged into nearby aquatic ecosystems. The antibiogram profiles and resistance genes of P. aeruginosa were evaluated in this study. Wastewater effluents were obtained from a hospital within a six-month sampling period. After the samples were processed and analysed, P. aeruginosa was identified by polymerase chain reaction (PCR) by amplifying OprI and OprL genes. The Kirby-Bauer diffusion technique was employed to check the susceptibility profiles of P. aeruginosa which were further interpreted using CLSI guidelines. A total of 21 resistance genes were investigated among the isolates. The sum of 81 positive P. aeruginosa were isolated in this study. This study's mean count of Pseudomonas aeruginosa ranged from 2.4 × 105 to 6.5 × 105 CFU/mL. A significant proportion of the isolates were susceptible to imipenem (93%), tobramycin (85%), norfloxacin (85%), aztreonam (70%), ciprofloxacin (51%), meropenem (47%), levofloxacin (43%), and gentamicin (40%). Meanwhile, a low susceptibility was recorded for amikacin and ceftazidime. The overall multiple antibiotics resistance index (MARI) ranged from 0.3 to 0.9, with 75% of the multidrug-resistant isolates. The assessment of β-lactam-resistant genes revealed blaOXA-1 (3.7%) and blaSHV (2.4%). The frequency of carbapenem genes was 6.6% for blaIMP, 6.6% for blaKPC, 6.6% for blaoxa-48, 2.2% for blaNDM-1, 2.2% for blaGES, and 2.2% for blaVIM. Of the aminoglycoside genes screened, 8.6% harboured strA, 11.5% harboured aadA, and 1.5% harboured aph(3)-Ia(aphA1). Only one non-β-lactamase gene (qnrA) was detected, with a prevalence of 4.9%. The findings of this study revealed a high prevalence of multidrug-resistant P. aeruginosa and resistance determinants potentially posing environmental health risks.

Relationship between COVID-19 and ICU-acquired colonization and infection related to multidrug-resistant bacteria: a prospective multicenter before-after study

PURPOSE

Patients presenting the most severe form of coronavirus disease 2019 (COVID-19) pneumonia, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have a prolonged intensive care unit (ICU) stay and are exposed to broad-spectrum antibiotics, but the impact of COVID-19 on antimicrobial resistance is unknown.

METHODS

Observational prospective before-after study in 7 ICUs in France. All consecutive patients with an ICU stay > 48 h and a confirmed SARS-CoV-2 infection were included prospectively and followed for 28 days. Patients underwent systematic screening for colonization with multidrug-resistant (MDR) bacteria upon admission and every week subsequently. COVID-19 patients were compared to a recent prospective cohort of control patients from the same ICUs. The primary objective was to investigate the association of COVID-19 with the cumulative incidence of a composite outcome including ICU-acquired colonization and/or infection related to MDR bacteria (ICU-MDR-col and ICU-MDR-inf, respectively).

RESULTS

From February 27th, 2020 to June 2nd, 2021, 367 COVID-19 patients were included, and compared to 680 controls. After adjustment for prespecified baseline confounders, the cumulative incidence of ICU-MDR-col and/or ICU-MDR-inf was not significantly different between groups (adjusted sub-hazard ratio [sHR] 1.39, 95% confidence interval [CI] 0.91-2.09). When considering both outcomes separately, COVID-19 patients had a higher incidence of ICU-MDR-inf than controls (adjusted sHR 2.50, 95% CI 1.90-3.28), but the incidence of ICU-MDR-col was not significantly different between groups (adjusted sHR 1.27, 95% CI 0.85-1.88).

CONCLUSION

COVID-19 patients had an increased incidence of ICU-MDR-inf compared to controls, but the difference was not significant when considering a composite outcome including ICU-MDR-col and/or ICU-MDR-inf.

Relationship between immunosuppression and intensive care unit-acquired colonization and infection related to multidrug-resistant bacteria: a prospective multicenter cohort study

PURPOSE

The impact of immunosuppression on intensive care unit (ICU)-acquired colonization and infection related to multidrug-resistant (MDR) bacteria (ICU-MDR-col and ICU-MDR-inf, respectively) is unknown.

METHODS

We carried out an observational prospective cohort study in 8 ICUs in France (all with single-bed rooms and similar organizational characteristics). All consecutive patients with an ICU stay > 48 h were included, regardless of immune status, and followed for 28 days. Patients underwent systematic screening for colonization with MDR bacteria upon admission and every week subsequently. Immunosuppression was defined as active cancer or hematologic malignancy, neutropenia, solid-organ transplant, use of steroids or immunosuppressive drugs, human immunodeficiency virus infection and genetic. The primary endpoint was the incidence rate of a composite outcome including ICU-MDR-col and/or ICU-MDR-inf.

RESULTS

750 patients (65.9% males, median age 65 years) were included, among whom 264 (35.2%) were immunocompromised. Reasons for ICU admission, severity scores and exposure to invasive devices and antibiotics during ICU stay were comparable between groups. After adjustment for center and pre-specified baseline confounders, immunocompromised patients had a lower incidence rate of ICU-MDR-col and/or ICU-MDR-inf (adjusted incidence ratio 0.68, 95% CI 0.52-0.91). When considered separately, the difference was significant for ICU-MDR-col, but not for ICU-MDR-inf. The distribution of MDR bacteria was comparable between groups, with a majority of Enterobacteriacae resistant to third-generation cephalosporins (~ 74%).

CONCLUSION

Immunocompromised patients had a significantly lower incidence rate of a composite outcome including ICU-MDR-col and/or ICU-MDR-inf. This finding points to the role of contact precautions and isolation measures, and could have important implications on antibiotic stewardship in this population.

Exposure and Health Effects of Bacteria in Healthcare Units: An Overview

Healthcare units consist of numerous people circulating daily, such as workers, patients, and companions, and these people are vehicles for the transmission of microorganisms, such as bacteria. Bacteria species may have different allergenic, pathogenic, infectious, or toxic properties that can affect humans. Hospital settings foment the proliferation of bacteria due to characteristics present in the indoor hospital environment. This review article aims to identify the potential health effects caused by bacterial contamination in the context of healthcare units, both in patients and in workers. A search was carried out for articles published in PubMed, Web of Science and Scopus, between 1 January 2000 and 31 October 2021, using the descriptor hospital exposure assessment bacteria. This bibliographic research found a total of 13 articles. Bacteria transmission occurs mainly due to the contact between healthcare workers and patients or through the handling of/contact with contaminated instruments or surfaces. The most common bacterial contaminants are Escherichia coli, Pseudomonas aeruginosa, Staphylococcus spp., Staphylococcus aureus and Micrococcus luteus, and the principal health effects of these contaminants are hospital-acquired infections and infections in immunocompromised people. A tight control of the disinfection methods is thus required, and its frequency must be increased to remove the microbial contamination of wards, surfaces and equipment. A better understanding of seasonal variations is important to prevent peaks of contamination.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host: An Update

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere and are only briefly discussed in the context of the immunocompromised host.

Infection control measures in times of antimicrobial resistance: a matter of solidarity

Control measures directed at carriers of multidrug-resistant organisms are traditionally approached as a trade-off between public interests on the one hand and individual autonomy on the other. We propose to reframe the ethical issue and consider control measures directed at carriers an issue of solidarity. Rather than asking “whether it is justified to impose strict measures”, we propose asking “how to best care for a person’s carriership and well-being in ways that do not imply an unacceptable risk for others?”. A solidarity approach could include elevating baseline levels of precaution measures and accepting certain risks in cases where there is exceptionally much at stake. A generous national compensation policy that also covers for costs related to dedicated care is essential in a solidarity approach. An additional benefit of reframing the questions is that it helps to better acknowledge that being subjected to control measures is a highly personal matter.

Two years study of prevalence and antibiotic resistance pattern of Gram-negative bacteria isolated from surgical site infections in the North of Iran

Objective

The present study aimed to investigate the frequency and antibiotic susceptibility pattern of Gram-negative bacteria (GNB) isolated from surgical site infections (SSIs) in the North of Iran.

Results

This cross-sectional study conducted over a two-year period during 2018–2020 on all cases of SSIs who had a positive culture for a GNB. Standard microbiological tests were followed for the bacterial isolation and identification. Antimicrobial susceptibility profiles were determined using disk diffusion method. During the study period, a total of 78 nonduplicated GNB isolated from SSIs. The most prevalent surgical procedures were fracture fixation (37.2%), and tissue debridement (23.1%). Klebsiella isolates showed the highest isolation rate (29.5%) followed by Enterobacter (28.2%), and Acinetobacter (16.7%). Antibiotic susceptibility results showed that Acinetobacter isolates were almost resistant to all of the tested antibiotics, except gentamicin, co-trimoxazole, and meropenem. Enterobacteriaceae isolates showed the lowest resistance against amikacin, co-trimoxazole, and imipenem. Overall, 49 (62.8%) of isolates were multiple drug-resistant (MDR). In summary, a remarkable rate of MDR isolates which showed an increasing trend during recent years is a serious alarm for the management of SSIs caused by GNB. Moreover, the results of regional assessments, provide good epidemiological background for comparing our situation with other regions.

Increased multidrug resistant isolates: new clinical burdens for 66 hospitals in Shanghai, 2015 to 2017

Background

To investigate the etiology of urinary tract and respiratory infections and the rate of drug resistant bacteria in Shanghai from 2015 to 2017, provide the support to the promotion of the correct clinical etiological specimens detection.

Methods

The retrospective questionnaire survey was conducted to obtain the antibiotic prescription rate, pathogen detection rate, and isolation rate of drug-resistant bacteria of the inpatients in 66 hospitals of Shanghai in 2015 and 2017.

Results

Although the detection rate of multidrug-resistant bacteria in sputum specimens has decreased, the clinical pathogen detection still relied mainly on sputum specimens in 2017. Among the sputum specis, the detection rates of extended-spectrum β-lactamase-producing Escherichia (ESBL-ESC), extended-spectrum β-lactamase Klebsiella pneumoniae (ESBL-KP), carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA) and methicillin-resistant Staphylococcus aureus (MRSA) in 2017 were 66.67%, 32.46%, 61.74%, 32.01% and 58.55% respectively. The detection rates of ESBL-ESC, ESBL-KP, CRAB, CRPA in 2017 were increased while the MRSA was decreased than 2015 (P<0.001). Among the blood samples, the detection rates of ESBL-ESC, ESBL-KP, CRAB, CRPA, MRSA and vancomycin-resistant Enterococcus sp (VRE) in 2017 were 53.71%, 31.43%, 50.80%, 19.43%, 43.87% and 0.55% respectively. The detection rates of ESBL-KP, CRAB, CRPA and MRSA increased while the rates of ESBL-ESC and VRE decreased compared with 2015 (P<0.005). The pathogens of multi-drug resistant bacteria were mainly detected from sputum specimens in 2017, which were all higher than detected from the blood specimens (P<0.001).

Conclusions

Most of the multi-drug resistant bacteria in Shanghai, especially in Acinetobacter baumannii or Pseudomonas aeruginosa are mainly detected from sputum specimens, indicating that the actual drug resistance may be overestimated.

Bloodstream infections caused by multidrug-resistant gram-negative bacteria: epidemiological, clinical and microbiological features

Background

Bloodstream infections (BSI) are associated with high morbidity and mortality. This scenario worsens with the emergence of drug-resistant pathogens, resulting in infections which are difficult to treat or even untreatable with conventional antimicrobials. The aim of this study is to describe the epidemiological aspects of BSI caused by multiresistant gram-negative bacilli (MDR-GNB).

Methods

We conducted a laboratory-based surveillance for gram-negative bacteremia over a 1-year period. The bacterial isolates were identified by MALDI-TOF/MS and the antimicrobial susceptibility testing was performed by VITEK®2. Resistance genes were identified through PCR assays.

Results

Of the 143 patients, 28.7% had infections caused by MDR-GNB. The risk factors for MDR bacteremia were male sex, age ≥ 60, previous antimicrobial use, liver disease and bacteremia caused by K. pneumoniae. K. pneumoniae was the most frequently observed causative agent and had the highest resistance level. Regarding the resistance determinants, SHV, TEM, OXA-1-like and CTX-M-gp1 were predominant enzymatic variants, whereas CTX-M-gp9, CTX-M-gp2, KPC, VIM, GES, OXA-48-like, NDM and OXA-23-like were considered emerging enzymes.

Conclusions

Here we demonstrate that clinically relevant antibiotic resistance genes are prevalent in this setting. We hope our findings support the development of intervention measures by policy makers and healthcare professionals to face antibiotic resistance.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4265-z) contains supplementary material, which is available to authorized users.

Ethics of Infection Control Measures for Carriers of Antimicrobial Drug-Resistant Organisms

Many countries have implemented infection control measures directed at carriers of multidrug-resistant organisms. To explore the ethical implications of these measures, we analyzed 227 consultations about multidrug resistance and compared them with the literature on communicable disease in general. We found that control measures aimed at carriers have a range of negative implications. Although moral dilemmas seem similar to those encountered while implementing control measures for other infectious diseases, 4 distinct features stand out for carriage of multidrug-resistant organisms: carriage presents itself as a state of being; carriage has limited relevance for the health of the carrier; carriage has little relevance outside healthcare settings; and antimicrobial resistance is a slowly evolving threat on which individual carriers have limited effect. These features are of ethical relevance because they influence the way we traditionally think about infectious disease control and urge us to pay more attention to the personal experience of the individual carrier.

Natural quorum sensing inhibitors effectively downregulate gene expression of Pseudomonas aeruginosa virulence factors

At present, anti-virulence drugs are being considered as potential therapeutic alternatives and/or adjuvants to currently failing antibiotics. These drugs do not kill bacteria but inhibit virulence factors essential for establishing infection and pathogenesis through targeting non-essential metabolic pathways reducing the selective pressure to develop resistance. We investigated the effect of naturally isolated plant compounds on the repression of the quorum sensing (QS) system which is linked to virulence/pathogenicity in Pseudomonas aeruginosa. Our results show that trans-cinnamaldehyde (CA) and salicylic acid (SA) significantly inhibit expression of QS regulatory and virulence genes in P. aeruginosa PAO1 at sub-inhibitory levels without any bactericidal effect. CA effectively downregulated both the las and rhl QS systems with lasI and lasR levels inhibited by 13- and 7-fold respectively compared to 3- and 2-fold reductions with SA treatment, during the stationary growth phase. The QS inhibitors (QSI) also reduced the production of extracellular virulence factors with CA reducing protease, elastase and pyocyanin by 65%, 22% and 32%, respectively. The QSIs significantly reduced biofilm formation and concomitantly with repressed rhamnolipid gene expression, only trace amount of extracellular rhamnolipids were detected. The QSIs did not completely inhibit virulence factor expression and production but their administration significantly lowered the virulence phenotypes at both the transcriptional and extracellular levels. This study shows the significant inhibitory effect of natural plant-derived compounds on the repression of QS systems in P. aeruginosa.

Influence of bacterial resistance on mortality in intensive care units: a registry study from 2000 to 2013 (IICU Study)

BACKGROUND

Bacterial resistance to antibiotics is a daily concern in intensive care units. However, few data are available concerning the clinical consequences of in-vitro-defined resistance.

AIM

To compare the mortality of patients with nosocomial infections according to bacterial resistance profiles.

METHODS

The prospective surveillance registry in 29 French intensive care units (ICUs) participating during the years 2000-2013 was retrospectively analysed. All patients presenting with a nosocomial infection in ICU were included.

FINDINGS

The registry contained 88,000 eligible patients, including 10,001 patients with a nosocomial infection. Among them, 3092 (36.7%) were related to resistant micro-organisms. Gram-negative bacilli exhibited the highest rate of resistance compared to Gram-positive cocci (52.8% vs 48.1%; P < 0.001). In-hospital mortality was higher in cases of patients with antibiotic-resistant infectious agents (51.9% vs 45.5%; P < 0.001), and critical care length of stay was longer (33 ± 26 vs 29 ± 22 days; P < 0.001). These results remained significant after SAPS II matching (P < 0.001) and in the Gram-negative bacilli and Gram-positive cocci subgroups. No difference in mortality was found with respect to origin prior to admission.

CONCLUSION

Patients with bacterial resistance had higher ICU mortality and increased length of stay, regardless of the bacterial species or origin of the patient.

An in-depth analysis of nosocomial bloodstream infections due to Gram-negative bacilli: clinical features, microbiological characteristics and predictors of mortality in a 1 year, prospective study in a large tertiary care Italian hospital

BACKGROUND

Bloodstream infections (BSI) due to Gram negative bacilli (GNB) represent a major concern among nosocomial infections, since they are noticeably associated with a high mortality rates, increase of healthcare costs and prolongation of hospital stay.

METHODS

Over a 12-month period (2014-2015) all the adult patients admitted to a university-based Italian hospital were monitored for development of BSIs due to GNB. Multiple logistics regression models were performed to assess the impact of patients' risk factors on the in-hospital and 14-day mortality.

RESULTS

During the study period 208 patients were diagnosed with at least a BSI due to a Gram negative species for an incidence rate of 12.8 cases/1,000 admissions (95%CI: 11.2-14.7). Multivariate analyses showed that multiple organ dysfunctions along with immune deficit and inadequate therapy in the first 48hrs were associated with a higher risk of death.

CONCLUSIONS

A thorough evaluation of both immune status and organ dysfunction at the onset of septic events, along with adequate antimicrobial therapy appear to be the most reliable factors in predicting the outcome in these infections. SOFA score can be efficaciously substituted to the single organ dysfunctions analysis in predicting mortality after these events.

Impact of Delayed Appropriate Antibiotic Therapy on Patient Outcomes by Antibiotic Resistance Status From Serious Gram-negative Bacterial Infections

BACKGROUND

To examine the clinical and economic burdens associated with delayed receipt of appropriate therapy among patients with Gram-negative bacteria (GNB) infections, stratified by antibiotic resistance status.

MATERIALS AND METHODS

Retrospective analysis using the Premier Hospital Database. Adult admissions (July 2011-September 2014) with evidence of complicated urinary tract infection, complicated intra-abdominal infection, hospital-associated pneumonia, or bloodstream infection, length of stay (LOS) ≥1 days and a positive GNB culture from a site consistent with infection type (culture draw date = index date) were identified and stratified by antibiotic susceptibility to index pathogens. Delayed appropriate therapy was defined as no receipt of antibiotic(s) with relevant microbiological activity on or within 2 days of index date. Inverse probability weighting and multivariate regression analyses were used to estimate the association between delayed appropriate therapy and outcomes. Generalized linear models were used to evaluate postindex duration of antibiotic therapy, LOS and total in-hospital costs. Logistic models were used to evaluate discharge destination and in-hospital mortality/discharge to hospice.

RESULTS

A total of 56,357 patients with GNB infections were identified (resistant, n = 6,055; susceptible, n = 50,302). Delayed appropriate therapy was received by 2,800 (46.2%) patients with resistant and 16,585 (33.0%) patients with susceptible infections. Using multivariate analysis, delayed appropriate therapy was associated with worse outcomes including ∼70% increase in LOS, ∼65% increase in total in-hospital costs and ∼20% increase in the risk of in-hospital mortality/discharge to hospice, regardless of susceptibility status.

CONCLUSIONS

Our results suggest that outcomes in patients with GNB infections, regardless of resistance status, significantly improve if timely appropriate therapy can be provided.

Risk factors for multidrug-resistant Gram-negative bacteria infection in intensive care units: A meta-analysis

AIMS

To identify the risk factors for multidrug-resistant Gram-negative bacteria systematically and provide suggestions and an evidence-base for clinical measures.

BACKGROUND

With the increase in the social population, changes in human behaviour and ecosystems, as well as economic development, bacteria have gradually produced drug resistance genes. These have swept through intensive care units causing high mortality.

METHODS

Relevant literature which included case-control and cohort studies published from January 1999 to March 2017 were searched in the Cochrane Library, PubMed, Web of Science, and Medline. Meta-analysis was performed by using StataSE version 12.0 software.

RESULTS

Eighteen studies of 235 publications were eligible. Male gender (OR 1.40, 95%CI 1.09, 1.80), having an operative procedure (OR 1.31, 95%CI 1.10, 1.56), a central venous catheter (OR 1.22, 95%CI 1.01, 1.48), mechanical ventilation (OR 1.25, 95%CI 1.07, 1.46), previous antibiotic therapy (OR 1.66, 95%CI 1.41, 1.96), length of ICU stay (weighted mean difference 8.18, 95%CI 0.27, 16.10), and types of health-associated infections were the identified risk factors for multidrug-resistant Gram-negative bacterial infection in intensive care units; moreover, diabetes mellitus was not.

CONCLUSION

Six risk factors were associated with multidrug-resistant Gram-negative bacterial infection in intensive care units. Antimicrobial stewardship, infection control, and medical staff prevention care are needed.

Control of Multidrug-Resistant Pseudomonas aeruginosa in Allogeneic Hematopoietic Stem Cell Transplant Recipients by a Novel Bundle Including Remodeling of Sanitary and Water Supply Systems

Background

Infections by multidrug-resistant Pseudomonas aeruginosa (MDRPa) are an important cause of morbidity and mortality in patients after allogeneic hematopoietic stem cell transplantation (HSCT). Humid environments can serve as a reservoir and source of infection by this pathogen. To minimize the risk of infection from these reservoirs, we performed extensive remodeling of sanitation and water installations as the focus of our hygiene bundle.

Methods

During the reconstruction of our transplantation unit (April 2011-April 2014) we implemented several technical modifications to reduce environmental contamination by and subsequent spreading of MDRPa, including a newly designed shower drain, disinfecting siphons underneath the sinks, and rimless toilets. During a 3-year study period (2012-2014), we tracked the number of patients affected by MDRPa (colonized and/or infected) and the outcome of infected patients, and monitored the environmental occurrence of this pathogen. We further performed whole-genome sequencing of nosocomial MDRPa strains to evaluate genotypic relationships between isolates.

Results

Whereas 31 (9.2%; 18 colonized, 13 infected) patients were affected in 2012 and 2013, the number decreased to 3 in 2014 (17%; 3 colonized, 0 infected). Lethality by MDRPa similarly decreased from 3.6% to 0%. Environmental detection of MDRPa decreased in toilets from 18.9% in 2012-2013 to 6.1% in the following year and from 8.1% to 3.0%, respectively, in shower outlets. Whole-genome sequencing showed close relationships between environmental and patient-derived isolates.

Conclusions

Hospital construction measures aimed at controlling environmental contamination by and spread of MDRPa are effective at minimizing the risk of highly lethal MDRPa infections.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere, and are only briefly discussed in the context of the immunocompromised host.

Management of multidrug resistant Gram-negative bacilli infections in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant (MDR) Gram-negative bacilli (GNB), as they are frequently exposed to antibiotics and the healthcare setting, and are regulary subject to invasive procedures. Nevertheless, no recommendations concerning prevention and treatment are available. A panel of experts revised the available evidence; this document summarizes their recommendations: (1) it is important to characterize the isolate's phenotypic and genotypic resistance profile; (2) overall, donor colonization should not constitute a contraindication to transplantation, although active infected kidney and lung grafts should be avoided; (3) recipient colonization is associated with an increased risk of infection, but is not a contraindication to transplantation; (4) different surgical prophylaxis regimens are not recommended for patients colonized with carbapenem-resistant GNB; (5) timely detection of carriers, contact isolation precautions, hand hygiene compliance and antibiotic control policies are important preventive measures; (6) there is not sufficient data to recommend intestinal decolonization; (7) colonized lung transplant recipients could benefit from prophylactic inhaled antibiotics, specially for Pseudomonas aeruginosa; (8) colonized SOT recipients should receive an empirical treatment which includes active antibiotics, and directed therapy should be adjusted according to susceptibility study results and the severity of the infection.

Evaluation of the ability of Acinetobacter baumannii to form biofilms on six different biomedical relevant surfaces

The human opportunistic pathogen, Acinetobacter baumannii, has the propensity to form biofilms and frequently cause medical device-related infections in hospitals. However, the physio-chemical properties of medical surfaces, in addition to bacterial surface properties, will affect colonization and biofilm development. The objective of this study was to compare the ability of A. baumannii to form biofilms on six different materials common to the hospital environment: glass, porcelain, stainless steel, rubber, polycarbonate plastic and polypropylene plastic. Biofilms were developed on material coupons in a CDC biofilm reactor. Biofilms were visualized and quantified using fluorescent staining and imaged using confocal laser scanning microscopy (CLSM) and by direct viable cell counts. Image analysis of CLSM stacks indicated that the mean biomass values for biofilms grown on glass, rubber, porcelain, polypropylene, stainless steel and polycarbonate were 0·04, 0·26, 0·62, 1·00, 2·08 and 2·70 μm(3) /μm(2) respectively. Polycarbonate developed statistically more biofilm mass than glass, rubber, porcelain and polypropylene. Viable cell counts data were in agreement with the CLSM-derived data. In conclusion, polycarbonate was the most accommodating surface for A. baumannii ATCC 17978 to form biofilms while glass was least favourable. Alternatives to polycarbonate for use in medical and dental devices may need to be considered.

SIGNIFICANCE AND IMPACT OF THE STUDY

In the hospital environment, Acinetobacter baumannii is one of the most persistent and difficult to control opportunistic pathogens. The persistence of A. baumannii is due, in part, to its ability to colonize surfaces and form biofilms. This study demonstrates that A. baumannii can form biofilms on a variety of different surfaces and develops substantial biofilms on polycarbonate - a thermoplastic material that is often used in the construction of medical devices. The findings highlight the need to further study the in vitro compatibility of medical materials that could be colonized by A. baumannii and allow it to persist in hospital settings.

Multidrug resistant Pseudomonas aeruginosa survey in a stream receiving effluents from ineffective wastewater hospital plants

BACKGROUND

Multi-drug resistant forms of Pseudomonas aeruginosa (MDRPA) are a major source of nosocomial infections and when discharged into streams and rivers from hospital wastewater treatment plants (HWWTP) they are known to be able to persist for extended periods. In the city of Manaus (Western Brazilian Amazon), the effluent of three HWWTPs feed into the urban Mindu stream which crosses the city from its rainforest source before draining into the Rio Negro. The stream is routinely used by Manaus residents for bathing and cleaning (of clothes as well as domestic utensils) and, during periods of flooding, can contaminate wells used for drinking water.

RESULTS

16S rRNA metagenomic sequence analysis of 293 cloned PCR fragments, detected an abundance of Pseudomonas aeruginosa (P. aeruginosa) at the stream's Rio Negro drainage site, but failed to detect it at the stream's source. An array of antimicrobial resistance profiles and resistance to all 14 tested antimicrobials was detected among P. aeruginosa cultures prepared from wastewater samples taken from water entering and being discharged from a Manaus HWWTP. Just one P. aeruginosa antimicrobial resistance profile, however, was detected from cultures made from Mindu stream isolates. Comparisons made between P. aeruginosa isolates' genomic DNA restriction enzyme digest fingerprints, failed to determine if any of the P. aeruginosa found in the Mindu stream were of HWWTP origin, but suggested that Mindu stream P. aeruginosa are from diverse origins. Culturing experiments also showed that P. aeruginosa biofilm formation and the extent of biofilm formation produced were both significantly higher in multi drug resistant forms of P. aeruginosa.

CONCLUSIONS

Our results show that a diverse range of MDRPA are being discharged in an urban stream from a HWWTP in Manaus and that P. aeruginosa strains with ampicillin and amikacin can persist well within it.

Healthcare-Associated Infections in Pediatric and Neonatal Intensive Care Units: Impact of Underlying Risk Factors and Antimicrobial Resistance on 30-Day Case-Fatality in Italy and Brazil

OBJECTIVES To describe trends in the epidemiology of healthcare-associated Infections (HAIs) in pediatric/neonatal intensive care units (ICUs) and to evaluate risk factors and impact of multidrug resistance in children admitted to ICUs. DESIGN Multicenter, retrospective, cohort study with a nested case-control study conducted from January 1, 2010, through December 31, 2014. SETTING Three tertiary care pediatric hospitals in Italy and Brazil with a total of 103 ICU beds. PATIENTS Inclusion criteria were admission to ICU during the study period, age at onset less than 18 years, and microbiologically confirmed HAI. RESULTS A total of 538 HAIs in 454 children were included; 93.3% of patients had comorbidities. Bloodstream infections were the leading pattern (45.4%). The cumulative incidence of HAI was 3.6/100 ICU admissions and the crude 30-day fatality rate was 5.7/1,000 admissions. The most frequently isolated pathogens were Enterobacteriaceae, followed by Pseudomonas aeruginosa and Staphylococcus aureus. Forty-four percent of isolates were multidrug-resistant (MDR). Two multivariate logistic regressions were performed. Factors independently associated with an MDR-HAI were country, previous antibiotics, transplantation, major surgery, and colonization by an MDR strain. Factors independently associated with 30-day case fatality were country, previous transplantation, fungal infection, bloodstream infection, lower respiratory tract infection, and infection caused by MDR strains. CONCLUSIONS Infection control and prevention can limit the spread of MDR strains and improve outcomes. Targeted surveillance programs collecting neonatal and pediatric HAI/bloodstream infection data and outcomes would allow global benchmarking. The next step is to identify methods to monitor key HAIs and integrate these into affordable intervention programs. Infect Control Hosp Epidemiol 2016;1-8.

From Bench-Top to Bedside: A Prospective In Vitro Antibiotic Combination Testing (iACT) Service to Guide the Selection of Rationally Optimized Antimicrobial Combinations against Extensively Drug Resistant (XDR) Gram Negative Bacteria (GNB)

Introduction

Combination therapy is increasingly utilized against extensively-drug resistant (XDR) Gram negative bacteria (GNB). However, choosing a combination can be problematic as effective combinations are often strain-specific. An in vitro antibiotic combination testing (iACT) service, aimed to guide the selection of individualized and rationally optimized combination regimens within 48 hours, was developed. We described the role and feasibility of the iACT service in guiding individualized antibiotic combination selection in patients with XDR-GNB infections.

Methods

A retrospective case review was performed in two Singapore hospitals from April 2009–June 2014. All patients with XDR-GNB and antibiotic regimen guided by iACT for clinical management were included. The feasibility and role of the prospective iACT service was evaluated. The following patient outcomes were described: (i) 30-day in-hospital all-cause and infection-related mortality, (ii) clinical response, and (iii) microbiological eradication in patients with bloodstream infections.

Results

From 2009–2014, the iACT service was requested by Infectious Disease physicians for 39 cases (20 P. aeruginosa, 13 A. baumannii and 6 K. pneumoniae). Bloodstream infection was the predominant infection (36%), followed by pneumonia (31%). All iACT recommendations were provided within 48h from request for the service. Prior to iACT-guided therapy, most cases were prescribed combination antibiotics empirically (90%). Changes in the empiric antibiotic regimens were recommended in 21 (54%) cases; in 14 (36%) cases, changes were recommended as the empiric regimens were found to be non-bactericidal in vitro. In 7 (18%) cases, the number of antibiotics used in combination empirically was reduced by the iACT service. Overall, low 30-day infection-related mortality (15%) and high clinical response (82%) were observed. Microbiological eradication was observed in 79% of all bloodstream infections.

Conclusions

The iACT service can be feasibly employed to guide the timely selection of rationally optimized combination regimens, and played a role in reducing indiscreet antibiotic use.

Association between infections caused by multidrug-resistant gram-negative bacteria and mortality in critically ill patients

The incidence of gram-negative multidrug-resistant (MDR) bacterial pathogens is increasing in hospitals and particularly in the intensive care unit (ICU) setting. The clinical consequences of infections caused by MDR pathogens remain controversial. The purpose of this review is to summarize the available data concerning the impact of these infections on mortality in ICU patients. Twenty-four studies, conducted exclusively in ICU patients, were identified through PubMed search over the years 2000-2015. Bloodstream infection was the only infection examined in eight studies, respiratory infections in four and variable infections in others. Comparative data on the appropriateness of empirical antibiotic treatment were provided by only seven studies. In ten studies the presence of antimicrobial resistance was not associated with increased mortality; on the contrary, in other studies a significant impact of antibiotic resistance on mortality was found, though, sometimes, mediated by inappropriate antimicrobial treatment. Therefore, a direct association between infections due to gram-negative MDR bacteria and mortality in ICU patients cannot be confirmed. Sample size, presence of multiple confounders and other methodological issues may influence the results. These data support the need for further studies to elucidate the real impact of infections caused by resistant bacteria in ICU patients.

Improving outcomes of severe infections by multidrug-resistant pathogens with polyclonal IgM-enriched immunoglobulins

The emergence of infections by multidrug-resistant (MDR) Gram-negative bacteria, which is accompanied by considerable mortality due to inappropriate therapy, led to the investigation of whether adjunctive treatment with one polyclonal IgM-enriched immunoglobulin preparation (IgGAM) would improve outcomes. One hundred patients in Greece with microbiologically confirmed severe infections by MDR Gram-negative bacteria acquired after admission to the Intensive Care Unit and treated with IgGAM were retrospectively analysed from a large prospective multicentre cohort. A similar number of patient comparators well-matched for stage of sepsis, source of infection, appropriateness of antimicrobials and co-morbidities coming from the same cohort were selected. All-cause 28-day mortality was the primary end point; mortality by extensively drug-resistant (XDR) pathogens and time to breakthrough bacteraemia were the secondary end points. Fifty-eight of the comparators and 39 of the IgGAM-treated cases died by day 28 (p 0.011). The OR for death under IgGAM treatment was 0.46 (95% CI 0.26-0.85). Stepwise regression analysis revealed that IgGAM was associated with favourable outcome whereas acute coagulopathy, cardiovascular failure, chronic obstructive pulmonary disease and chronic renal disease were associated with unfavourable outcome. Thirty-nine of 62 comparators (62.9%) were infected by XDR Gram-negative bacteria and died by day 28 compared with 25 of 65 cases treated with IgGAM (38.5%) (p 0.008). Median times to breakthrough bacteraemia were 4 days and 10 days, respectively (p <0.0001). Results favour the use of IgGAM as an adjunct to antimicrobial treatment for the management of septic shock caused by MDR Gram-negative bacteria. A prospective randomized trial is warranted.

Prevalence and risk factors associated with colonization and infection of extensively drug-resistant Pseudomonas aeruginosa: a systematic review

Pseudomonas aeruginosa is a Gram-negative human pathogen with extensively drug-resistant (XDR) strains emerging in hospitals across the globe. This systematic review is focused on the worldwide prevalence of XDR P. aeruginosa (XDR-PA) and on the risk factors associated with its colonization and infection, based on literature available through PubMed, Web of Science and BioMed Central databases. An overview of surveillance systems is provided as well as a synopsis on the prevalence of XDR-PA, showing an increase in recent reports. Risk factors independently associated with XDR-PA colonization or infections are described in four groups with reference to antimicrobial therapy, medical devices as well as patient- and hospital environment-related factors.