Healthcare utilization and costs associated with S. aureus and P. aeruginosa pneumonia in the intensive care unit: a retrospective observational cohort study in a US claims database

Antibacterial and antibiofilm potentials of vancomycin-loaded niosomal drug delivery system against methicillin-resistant Staphylococcus aureus (MRSA) infections

The threat of methicillin-resistant Staphylococcus aureus (MRSA) is increasing worldwide, making it significantly necessary to discover a novel way of dealing with related infections. The quick spread of MRSA isolates among infected individuals has heightened public health concerns and significantly limited treatment options. Vancomycin (VAN) can be applied to treat severe MRSA infections, and the indiscriminate administration of this antimicrobial agent has caused several concerns in medical settings. Owing to several advantageous characteristics, a niosomal drug delivery system may increase the potential of loaded antimicrobial agents. This work aims to examine the antibacterial and anti-biofilm properties of VAN-niosome against MRSA clinical isolates with emphasis on cytotoxicity and stability studies. Furthermore, we aim to suggest an effective approach against MRSA infections by investigating the inhibitory effect of formulated niosome on the expression of the biofilm-associated gene (icaR). The thin-film hydration approach was used to prepare the niosome (Tween 60, Span 60, and cholesterol), and field emission scanning electron microscopy (FE-SEM), an in vitro drug release, dynamic light scattering (DLS), and entrapment efficiency (EE%) were used to investigate the physicochemical properties. The physical stability of VAN-niosome, including hydrodynamic size, polydispersity index (PDI), and EE%, was analyzed for a 30-day storage time at 4 °C and 25 °C. In addition, the human foreskin fibroblast (HFF) cell line was used to evaluate the cytotoxic effect of synthesized niosome. Moreover, minimum inhibitory and bactericidal concentrations (MICs/MBCs) were applied to assess the antibacterial properties of niosomal VAN formulation. Also, the antibiofilm potential of VAN-niosome was investigated by microtiter plate (MTP) and real-time PCR methods. The FE-SEM result revealed that synthesized VAN-niosome had a spherical morphology. The hydrodynamic size and PDI of VAN-niosome reported by the DLS method were 201.2 nm and 0.301, respectively. Also, the surface zeta charge of the prepared niosome was - 35.4 mV, and the EE% ranged between 58.9 and 62.5%. Moreover, in vitro release study revealed a sustained-release profile for synthesized niosomal formulation. Our study showed that VAN-niosome had acceptable stability during a 30-day storage time. Additionally, the VAN-niosome had stronger antibacterial and anti-biofilm properties against MRSA clinical isolates compared with free VAN. In conclusion, the result of our study demonstrated that niosomal VAN could be promising as a successful drug delivery system due to sustained drug release, negligible toxicity, and high encapsulation capacity. Also, the antibacterial and anti-biofilm studies showed the high capacity of VAN-niosome against MRSA clinical isolates. Furthermore, the results of real-time PCR exhibited that VAN-niosome could be proposed as a powerful strategy against MRSA biofilm via down-regulation of icaR gene expression.

Opportunistic Pathogens in Drinking Water Distribution Systems-A Review

In contrast to "frank" pathogens, like Salmonella entrocolitica, Shigella dysenteriae, and Vibrio cholerae, that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a host with a weakened immune system and rarely in a healthy host. Historically, drinking water treatment has focused on control of frank pathogens, particularly those from human or animal sources (like Giardia lamblia, Cryptosporidium parvum, or Hepatitis A virus), but in recent years outbreaks from drinking water have increasingly been due to opportunistic pathogens. Characteristics of opportunistic pathogens that make them problematic for water treatment include: (1) they are normally present in aquatic environments, (2) they grow in biofilms that protect the bacteria from disinfectants, and (3) under appropriate conditions in drinking water systems (e.g., warm water, stagnation, low disinfectant levels, etc.), these bacteria can amplify to levels that can pose a public health risk. The three most common opportunistic pathogens in drinking water systems are Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa. This report focuses on these organisms to provide information on their public health risk, occurrence in drinking water systems, susceptibility to various disinfectants, and other operational practices (like flushing and cleaning of pipes and storage tanks). In addition, information is provided on a group of nine other opportunistic pathogens that are less commonly found in drinking water systems, including Aeromonas hydrophila, Klebsiella pneumoniae, Serratia marcescens, Burkholderia pseudomallei, Acinetobacter baumannii, Stenotrophomonas maltophilia, Arcobacter butzleri, and several free-living amoebae including Naegleria fowleri and species of Acanthamoeba. The public health risk for these microbes in drinking water is still unclear, but in most cases, efforts to manage Legionella, mycobacteria, and Pseudomonas risks will also be effective for these other opportunistic pathogens. The approach to managing opportunistic pathogens in drinking water supplies focuses on controlling the growth of these organisms. Many of these microbes are normal inhabitants in biofilms in water, so the attention is less on eliminating these organisms from entering the system and more on managing their occurrence and concentrations in the pipe network. With anticipated warming trends associated with climate change, the factors that drive the growth of opportunistic pathogens in drinking water systems will likely increase. It is important, therefore, to evaluate treatment barriers and management activities for control of opportunistic pathogen risks. Controls for primary treatment, particularly for turbidity management and disinfection, should be reviewed to ensure adequacy for opportunistic pathogen control. However, the major focus for the utility's opportunistic pathogen risk reduction plan is the management of biological activity and biofilms in the distribution system. Factors that influence the growth of microbes (primarily in biofilms) in the distribution system include, temperature, disinfectant type and concentration, nutrient levels (measured as AOC or BDOC), stagnation, flushing of pipes and cleaning of storage tank sediments, and corrosion control. Pressure management and distribution system integrity are also important to the microbial quality of water but are related more to the intrusion of contaminants into the distribution system rather than directly related to microbial growth. Summarizing the identified risk from drinking water, the availability and quality of disinfection data for treatment, and guidelines or standards for control showed that adequate information is best available for management of L. pneumophila. For L. pneumophila, the risk for this organism has been clearly established from drinking water, cases have increased worldwide, and it is one of the most identified causes of drinking water outbreaks. Water management best practices (e.g., maintenance of a disinfectant residual throughout the distribution system, flushing and cleaning of sediments in pipelines and storage tanks, among others) have been shown to be effective for control of L. pneumophila in water supplies. In addition, there are well documented management guidelines available for the control of the organism in drinking water distribution systems. By comparison, management of risks for Mycobacteria from water are less clear than for L. pneumophila. Treatment of M. avium is difficult due to its resistance to disinfection, the tendency to form clumps, and attachment to surfaces in biofilms. Additionally, there are no guidelines for management of M. avium in drinking water, and one risk assessment study suggested a low risk of infection. The role of tap water in the transmission of the other opportunistic pathogens is less clear and, in many cases, actions to manage L. pneumophila (e.g., maintenance of a disinfectant residual, flushing, cleaning of storage tanks, etc.) will also be beneficial in helping to manage these organisms as well.

Hospital re-admission after critical care survival: a systematic review and meta-analysis

Survivors of critical illness frequently require increased healthcare resources after hospital discharge. We undertook a systematic review and meta-analysis to assess hospital re-admission rates following critical care admission and to explore potential re-admission risk factors. We searched the MEDLINE, Embase and CINAHL databases on 05 March 2020. Our search strategy incorporated controlled vocabulary and text words for hospital re-admission and critical illness, limited to the English language. Two reviewers independently applied eligibility criteria and assessed quality using the Newcastle Ottawa Score checklist and extracted data. The primary outcome was acute hospital re-admission in the year after critical care discharge. Of the 8851 studies screened, 87 met inclusion criteria and 41 were used within the meta-analysis. The analysis incorporated data from 3,897,597 patients and 741,664 re-admission episodes. Pooled estimates for hospital re-admission after critical illness were 16.9% (95%CI: 13.3-21.2%) at 30 days; 31.0% (95%CI: 24.3-38.6%) at 90 days; 29.6% (95%CI: 24.5-35.2%) at six months; and 53.3% (95%CI: 44.4-62.0%) at 12 months. Significant heterogeneity was observed across included studies. Three risk factors were associated with excess acute care rehospitalisation one year after discharge: the presence of comorbidities; events during initial hospitalisation (e.g. the presence of delirium and duration of mechanical ventilation); and subsequent infection after hospital discharge. Hospital re-admission is common in survivors of critical illness. Careful attention to the management of pre-existing comorbidities during transitions of care may help reduce healthcare utilisation after critical care discharge. Future research should determine if targeted interventions for at-risk critical care survivors can reduce the risk of subsequent rehospitalisation.

Biochanin A as an α-hemolysin inhibitor for combating methicillin-resistant Staphylococcus aureus infection

Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen that poses a significant risk to global health today. In S. aureus, α-hemolysin is an important virulence factor as it contributes to the capacity of the bacteria to infect the host. Here, we showed that biochanin A (bioA), an isoflavone present in red clover, cabbage and alfalfa, effectively inhibited hemolytic activity at a dose as low as 32 μg/mL. Further, western blot and RT-qPCR data showed that bioA reduced the production and expression of MRSA hemolysin in a dose-dependent manner. In addition, when different concentrations of bioA were added to a coculture system of A549 cells and S. aureus, it could significantly decrease cell injury. Importantly, the in vivo study showed that bioA could protect mice from pneumonia caused by a lethal dose of MRSA, as evidenced by improving their survival and reducing the number of bacterial colonies in lung tissues, the secretion of hemolysin into alveolar lavage fluid and the degree of pulmonary edema. In conclusion, biochanin A protected the host from MRSA infection by inhibiting the expression of the hemolysin of MRSA, which may provide experimental evidence for its development to a potential anti-MRSA drug.

A Single- and Multiple-Dose Study To Characterize the Pharmacokinetics, Safety, and Tolerability of Imipenem and Relebactam in Healthy Chinese Participants

Relebactam/imipenem/cilastatin is approved in the United States to treat complicated urinary tract and intra-abdominal infections in patients who have limited or no alternative treatment options and hospital-acquired bacterial pneumonia (HABP)/ventilator-associated bacterial pneumonia (VABP). Initial pharmacokinetic, safety, and tolerability studies of relebactam with and without imipenem/cilastatin included mostly Caucasian participants. This study evaluated the pharmacokinetics, safety, and tolerability of relebactam/imipenem/cilastatin in 12 healthy Chinese participants after three single doses of increasing concentrations (relebactam at 125, 250, or 500 mg; cilastatin at 250, 500, or 1,000 mg; and imipenem at 250, 500, or 1,000 mg) and after multiple doses every 6 h of a single concentration (relebactam at 250 mg, cilastatin at 500 mg, and imipenem at 500 mg) for 14 days. After single doses, the area under the concentration-time curve (AUC) extrapolated to infinity (relebactam, 15.0 to 70.7 h · mg/liter; imipenem, 24.1 to 109.8 h · mg/liter; cilastatin, 18.4 to 95.3 h · mg/liter) and the AUC from 0 to 6 h (relebactam, 14.2 to 66.3 h · mg/liter; imipenem, 23.4 to 107.3 h · mg/liter; cilastatin, 18.3 to 94.4 h · mg/liter) increased in a dose-dependent manner; clearance (relebactam, 6.9 to 8.3 liters/h; imipenem, 8.6 to 10.4 liters/h; cilastatin, 10.5 to 13.6 liters/h) and half-life (relebactam, 1.4 to 1.6 h; imipenem, 1.0 to 1.2 h; cilastatin, 0.7 to 1.0 h) were consistent between doses. Pharmacokinetic parameters after multiple doses were similar to parameters after a single dose (geometric mean ratios of 0.8 to 1.0 for all three agents). Relebactam/imipenem/cilastatin was well tolerated; mild adverse events occurred during single dosing, and one participant experienced serious adverse events after multiple doses. Pharmacokinetics and safety data are comparable with data from participants of other ethnicities, supporting the use of relebactam/imipenem/cilastatin at the approved dose and schedule in Chinese patients.

Comparative lung distribution of radiolabeled tobramycin between nebulized and intravenous administration in a mechanically-ventilated ovine model, an observational study

BACKGROUND

Ventilator-associated pneumonia is common and is treated using nebulized antibiotics. Although adequate pulmonary biodistribution is important for antibiotic effect, there is a lack of data for both intravenous (IV) and nebulized antibiotic administration during mechanical ventilation.

OBJECTIVE

To describe the comparative pulmonary regional distribution of IV and nebulized technetium-99m-labeled tobramycin (99mTc-tobramycin) 400 mg in a mechanically-ventilated ovine model.

METHODS

The study was performed in a mechanically-ventilated ovine model. 99mTc-tobramycin 400 mg was obtained using a radiolabeling process. Computed tomography (CT) was performed. Ten sheep were given 99mTc-tobramycin 400 mg via either an IV (five sheep) or nebulized (five sheep) route. Planar images (dorsal, ventral, left lateral and right lateral) were obtained using a gamma camera. Blood samples were obtained every 15 min for 1 h (4 time points) and lung, liver, both kidney, and urine samples were obtained post-mortem.

RESULTS

Ten sheep were anesthetized and mechanically ventilated. Whole-lung deposition of nebulized 99mTc-tobramycin 400 mg was significantly lower than with IV (8.8% vs. 57.1%, P<0.001). For both administration routes, there was significantly lower deposition in upper lung zones compared with the rest of the lungs. Dorsal deposition was significantly higher with nebulized 99mTc-tobramycin 400 mg compared with IV (68.9% vs. 58.9%, P=0.003). Lung concentrations of 99mTc-tobramycin were higher with IV compared with nebulized administration. There were significantly higher concentrations of 99mTc-tobramycin in blood, liver and urine with IV administration compared with nebulized.

CONCLUSIONS

Nebulization resulted in lower whole and regional lung deposition of 99mTc-tobramycin compared with IV administration and appeared to be associated with low blood and extra-pulmonary organ concentrations.

Ability of chlorhexidine, octenidine, polyhexanide and chloroxylenol to inhibit metabolism of biofilm-forming clinical multidrug-resistant organisms

Purpose

This in vitro study was designed to determine if standard antiseptics used for skin and environmental surface cleansing can disrupt the metabolic activity (as a measure of viability) of multidrug-resistant gram-negative bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus isolates within their native biofilms.

Methods

Sixty clinical isolates of multidrug-resistant bacteria were selected for testing in different chlorhexidine gluconate, octenidine, polyhexanide and chloroxylenol concentrations. Metabolic inhibition of biofilm for each clinical isolate was analysed using a biofilm viability assay.

Results

Chlorhexidine gluconate (mean = 83.8% ± 9.8%) and octenidine (mean = 84.5% ± 6.8%) showed the greatest efficacy against biofilms of the tested microorganisms, with the greatest efficacies against MRSA. The antiseptics demonstrated the least efficacy against biofilms of Pseudomonas aeruginosa.

Conclusion

Chlorhexidine gluconate and octenidine showed the greatest level of bacterial metabolic inhibition and were statistically equivalent. Polyhexanide was more effective than chloroxylenol, but both were inferior to chlorhexidine gluconate and octenidine against the tested organisms.

Antimicrobial approaches in the prevention of Staphylococcus aureus infections: a review

Background

The prophylactic application of antimicrobials that are active against Staphylococcus aureus can prevent infections. However, implementation in clinical practice is limited. We have reviewed antimicrobial approaches for the prevention of S. aureus infections.

Methods

We searched the Cochrane Central Register of Controlled Trials, PubMed/MEDLINE and EMBASE databases and trial registries using synonyms for S. aureus, infections and prevention as search terms. We included randomized controlled trials and systematic reviews only.

Results

Most studies were conducted with mupirocin. Mupirocin is effective in preventing S. aureus infections in patients receiving dialysis treatment and in surgical patients, particularly if the patients are carriers of S. aureus. The combination of mupirocin and chlorhexidine, but not chlorhexidine alone, is also effective against S. aureus infections. So far, vaccines have not proven successful in protecting against S. aureus infections. Regarding prophylactic povidone-iodine and systemic antibiotics, there is limited evidence supporting their effectiveness against S. aureus infections. Antimicrobial honey has not been proven to be more effective or non-inferior to mupirocin in protecting against S. aureus infections.

Conclusions

The current evidence supports the use of mupirocin as prophylaxis for preventing infections with S. aureus, particularly in carriers and in the surgical setting or in patients receiving dialysis treatment. Other antimicrobial agents have not been sufficiently proven to be effective so far, or have been proven ineffective. New trials with vaccines and anti-staphylococcal peptides are currently underway and may lead to new preventive strategies in the future.

Fast-track extubation in patients after intracranial hematoma surgery

Early extubation, also known as fast track, is desirable after intracranial hematoma surgery to avoid ventilator-associated complications associated with admission to an intensive care unit (ICU). The objective of the present study was to determine whether ICU stay and ventilator-associated complications are reduced in patients who received surgery for intracranial hematoma if they are extubated early. A total of 17 patients were randomly assigned to two groups: In Group 1, patients were extubated early or using the fast track method, while those in Group 2 were conventionally extubated at a later stage and were managed at the ICU. Patients from both groups were assessed on admission to the operating room per the established standards and after the selection criteria had been confirmed, general anesthesia was applied. Extubation time and hemodynamic stability (number of anesthetic adjustments required to maintain hemodynamic parameters within 20% of the predicted values) were assessed post-operatively. Patients in the conventional group (n=10) were transferred to the ICU and extubated at 8 h post-operatively; hemodynamic stability and the presence of complications were evaluated. The fast track group had no complications associated with ventilation or any other parameter. All patients extubated in a conventional manner and who were transferred to the ICU presented with complications, including seizures, aspiration, atelectasis or failed extubation. In the future, fast track should be regarded as a routine technique in patients who meet the required criteria, so that they may be discharged quickly and with fewer complications. The present study was authorized by the ethics committee of the hospital and the research sub-directorate with the number AN14-003; it was submitted to and approved by the ISRCTN registry for clinical trials (ID, ISRCTN16924441).

Measuring the in-hospital costs of Pseudomonas aeruginosa pneumonia: methodology and results from a German teaching hospital

Background

Pseudomonas aeruginosa-related pneumonia is an ongoing healthcare challenge. Estimating its financial burden is complicated by the time-dependent nature of the disease.

Methods

Two hundred thirty-six cases of Pseudomonas aeruginosa-related pneumonia were recorded at a 2000 bed German teaching hospital between 2011 and 2014. Thirty-five cases (15%) were multidrug-resistant (MDR) Pseudomonas aeruginosa. Hospital- and community-acquired cases were distinguished by main diagnoses and exposure time. The impact of Pseudomonas aeruginosa-related pneumonia on the three endpoints cost, reimbursement, and length of stay was analyzed, taking into account (1) the time-dependent nature of exposure, (2) clustering of costs within diagnostic groups, and (3) additional confounders.

Results

Pseudomonas aeruginosa pneumonia is associated with substantial additional costs that are not fully reimbursed. Costs are highest for hospital-acquired cases (€19,000 increase over uninfected controls). However, community-acquired cases are also associated with a substantial burden (€8400 when Pseudomonas aeruginosa pneumonia is the main reason for hospitalization, and €6700 when not). Sensitivity analyses for hospital-acquired cases showed that ignoring or incorrectly adjusting for time-dependency substantially biases results. Furthermore, multidrug-resistance was rare and only showed a measurable impact on the cost of community-acquired cases.

Conclusions

Pseudomonas aeruginosa pneumonia creates a substantial financial burden for hospitals. This is particularly the case for nosocomial infections. Infection control interventions could yield significant cost reductions. However, to evaluate the potential effectiveness of different interventions, the time-dependent aspects of incremental costs must be considered to avoid introduction of bias.

Culture-Confirmed Staphylococcus aureus Infection after Elective Hysterectomy: Burden of Disease and Risk Factors

Background: Our study sought to describe the incidence of culture-confirmed postsurgical Staphylococcus aureus infection after elective hysterectomy and evaluate patient characteristics, risk factors, and economic consequences associated with Staphylococcus aureus infection. Methods: This was a retrospective cohort study of patients in the United States (≥18 years old; Kaiser Permanente health plan members) who underwent elective hysterectomy from 2007 to 2013. Hysterectomies were categorized by surgical setting (inpatient vs. outpatient) and procedure (abdominal, laparoscopic, or vaginal). We estimated the cumulative incidence of culture-confirmed Staphylococcus aureus infection (90 days post-surgery) and compared healthcare resource utilization and costs (within 120 days post-surgery) among patients with/without Staphylococcus aureus infection or with other infection. Results: Among 30,960 patients identified, 20,675 underwent inpatient hysterectomy (abdominal: 47.8%; laparoscopic: 24.8%; vaginal: 27.3%), and 10,285 underwent outpatient hysterectomy (laparoscopic: 86.1%; vaginal: 13.9%). The incidence of culture-confirmed Staphylococcus aureus infection was 0.8% and 0.4% for inpatient (abdominal: 1.2%; laparoscopic: 0.5%; vaginal: 0.2%) and outpatient (laparoscopic: 0.5%; vaginal: 0.1%) surgery, respectively. Patients with Staphylococcus aureus infection had more emergency department visits, hospitalizations, and re-operations compared with patients without infection or with non-Staphylococcus aureus infection. Mean total costs for patients with Staphylococcus aureus infection were higher (inpatient: $18,261; outpatient: $4,422) compared with patients without infection (inpatient: $6,171; p < 0.0001; outpatient: $905; p = 0.0023) or non-Staphylococcus aureus infection (inpatient: $11,207; p = 0.0117; outpatient: $3,005; p = 0.2117). Conclusions: Culture-confirmed postsurgical Staphylococcus aureus infection incidence was predominately associated with procedure type rather than surgical setting. Patients with post-surgical Staphylococcus aureus infection had higher health care utilization and costs than those without infection or with other infection types. Additional effective infection control strategies are needed to reduce the morbidity and costs associated with Staphylococcus aureus infection.

Treatment Efficacy of MEDI3902 in Pseudomonas aeruginosa Bloodstream Infection and Acute Pneumonia Rabbit Models

Pseudomonas aeruginosa is a challenge for clinicians due to increasing drug resistance and dwindling treatment options. We report on the activity of MEDI3902, an antibody targeting type 3 secretion protein PcrV and Psl exopolysaccharide, in rabbit bloodstream and lung infection models. MEDI3902 prophylaxis or treatment was protective in both acute models and exhibited enhanced activity when combined with a subtherapeutic dose of meropenem.

Pseudomonas aeruginosa is a challenge for clinicians due to increasing drug resistance and dwindling treatment options. We report on the activity of MEDI3902, an antibody targeting type 3 secretion protein PcrV and Psl exopolysaccharide, in rabbit bloodstream and lung infection models. MEDI3902 prophylaxis or treatment was protective in both acute models and exhibited enhanced activity when combined with a subtherapeutic dose of meropenem. These findings further support MEDI3902 for the prevention or treatment of serious P. aeruginosa infections.

Optimizing Antibiotic Administration for Pneumonia

Pneumonia, including community-acquired bacterial pneumonia, hospital-acquired bacterial pneumonia, and ventilator-acquired bacterial pneumonia, carries unacceptably high morbidity and mortality. Despite advances in antimicrobial therapy, emergence of multidrug resistance and high rates of treatment failure have made optimization of antibiotic efficacy a priority. This review focuses on pharmacokinetic and pharmacodynamic approaches to antibacterial optimization within the lung environment and in the setting of critical illness. Strategies for including these approaches in drug development programs as well as clinical practice are described and reviewed.

Carbapenem-Nonsusceptible Gram-Negative Pathogens in ICU and Non-ICU Settings in US Hospitals in 2017: A Multicenter Study

Background

Infections caused by Gram-negative pathogens resistant to carbapenems have limited treatment options and are associated with increased morbidity and mortality. We evaluated the rates, infection sources, and pathogen types associated with carbapenem-nonsusceptible (Carb-NS) Gram-negative isolates in intensive care unit (ICU) and non-ICU settings in a large US hospital database.

Methods

We conducted a retrospective cross-sectional analysis of carbapenem susceptibility of all nonduplicate isolates of Gram-negative pathogens collected from January 1, 2017, to December 31, 2017, at 358 US hospitals in the BD Insights Research Database. Carb-NS isolates included all pathogens reported at the institutional level as intermediate or resistant.

Results

Of 312 075 nonduplicate Gram-negative isolates, 10 698 (3.4%) were Carb-NS. Respiratory samples were the most frequent source of Carb-NS isolates (35.2%); skin/wound accounted for 23.6%. Pseudomonas aeruginosa was the most common Carb-NS pathogen (58.5% of isolates), and about 30% were Enterobacteriaceae. The highest rates of Carb-NS were found in Acinetobacter spp. (35.6%) and P. aeruginosa (14.6%). The rate of Carb-NS was significantly higher in ICU (5.4%) vs non-ICU settings (2.7%; P < .0001 in univariate analysis). This difference remained significant in multivariable analysis after adjusting for infection and hospital characteristics (odds ratio, 1.35; 95% confidence interval, 1.17–1.56; P < .0001).

Conclusions

Infections caused by Carb-NS isolates pose a significant clinical problem across different sources of infection, species of pathogen, and hospital settings. Widespread infection prevention and antimicrobial stewardship initiatives, in combination with new treatment options, may be required to reduce the burden of carbapenem resistance in health care settings.

Impact of selective digestive decontamination without systemic antibiotics in a major heart surgery intensive care unit

PURPOSE

The incidence density of ventilator-associated pneumonia (VAP) is higher in patients undergoing major heart surgery than in other populations, despite the introduction of bundles of preventive measures, because many risk factors are not amenable to intervention. Selective digestive decontamination (SDD) has been shown to be efficacious for decreasing the frequency of VAP, although it has not been incorporated into the routine of most intensive care units. The objective of our study was to evaluate the efficacy of SDD without parenteral antibiotics for preventing VAP in a major heart surgery intensive care unit.

METHODS

We compared the incidence of VAP before the introduction of SDD (17 months) and during the 17 months after the introduction of SDD and examined its ecologic influence.

RESULTS

The rates of VAP in the overall population before and during the intervention were 16.26/1000 days and 6.80 episodes/1000 days of mechanical ventilation, respectively (P = .01). The rates of VAP in the 173 patients remaining under mechanical ventilation > 48 hours after surgery were, respectively, 25.85/1000 days of mechanical ventilation versus 12.06 episodes/1000 days of mechanical ventilation (P = .04). We found a significant reduction in the number of patients with multidrug-resistant microorganisms (P = .01) in the second period of the study.

CONCLUSIONS

Our study shows that SDD without parenteral antibiotics can reduce the incidence of VAP in high-risk patients after major heart surgery, with no significant ecologic influence.

Novel Staphyloxanthin Inhibitors with Improved Potency against Multidrug Resistant Staphylococcus aureus

Diapophytoene desaturase (CrtN) is a potential novel target for intervening in the biosynthesis of the virulence factor staphyloxanthin. In this study, 38 1,4-benzodioxan-derived CrtN inhibitors were designed and synthesized to overwhelm the defects of leading compound 4a. Derivative 47 displayed superior pigment inhibitory activity, better hERG inhibitory properties and water solubility, and significantly sensitized MRSA strains to immune clearance in vitro. Notably, 47 displayed excellent efficacy against pigmented S. aureus Newman, Mu50 (vancomycin-intermediate MRSA, VISA), and NRS271 (linezolid-resistant MRSA, LRSA) comparable to that of linezolid and vancomycin in vivo.

The epidemiology of nonventilator hospital-acquired pneumonia in the United States

BACKGROUND

Nonventilator hospital-acquired pneumonia (NV-HAP) is among the most common hospital-acquired infections. The purpose of our study was to quantify the incidence and influence of NV-HAP in the United States using a national dataset.

METHODS

The 2012 US National Inpatient Sample dataset was used to compare an NV-HAP group to 4 additional group cohorts: pneumonia on admission, general hospital admissions, matched on mortality and disease severity, and ventilator-associated pneumonia (VAP). The main outcome was NV-HAP incidence. The secondary outcome was to compare hospital length of stay, total hospital charges, and mortality between the NV-HAP group and the 4 additional group cohorts.

RESULTS

The overall incidence of NV-HAP was 1.6%, which represents a rate of 3.63 per 1,000 patient-days. NV-HAP was associated with increased total hospital charges, a longer hospital length of stay, and greater likelihood of death in comparison to all groups except patients with VAP.

CONCLUSION

NV-HAP is an underappreciated and serious patient safety issue, resulting in significant increases in cost, length of stay, and mortality. Efforts toward prevention of NV-HAP should be raised to the same level of concern as VAP prevention.

Experimental phage therapy against haematogenous multi-drug resistant Staphylococcus aureus pneumonia in mice

BACKGROUND

Community-acquired haematogenous Staphylococcus aureus pneumonia is a rare infection, though it can be acquired nosocomially. Currently, antibiotics used against S. aureus pneumonia have shown reduced efficacy. Thus, there is need for an alternative therapy against multidrug-resistant S. aureus (MDRSA) strains in the community.

OBJECTIVE

We sought to determine the efficacy of environmentally-obtained S. aureus lytic phage against haematogenous MDRSA pneumonia in mice.

METHODS

Phages and MDRSA were isolated from sewage samples collected within Nairobi County, Kenya. Isolated S. aureus bacteria were screened for resistance against ceftazidime, oxacillin, vancomycin, netilmicin, gentamicin, erythromycin, trimethroprim-sulfamethoxazole and cefuroxime. Thirty BALB/c mice aged six to eight weeks were randomly assigned into three groups: the MDRSA-infection group (n = 20), the phage-infection group (n = 5) and the non-infection group (n = 5). Mice were infected with either MDRSA or phage (108 CFU/mL) and treated after 72 hours with a single dose of clindamycin (8 mg/kg/bwt) or 108 PFU/mL of phage or a combination therapy (clindamycin and phage). The efficacy of phage, clindamycin or clindamycin with phage combination was determined using resolution of lung pathology and bacterial load in lung homogenates.

RESULTS

The viable MDRSA count was 0.5 ± 0.2 log₁₀ CFU/gm in the phage-treated group, 4.4 ± 0.2 log₁₀ CFU/gm in the clindamycin-treated group and 4.0 ± 0.2 log₁₀ CFU/gm in the combination-treated group. The efficacy of phage therapy was significantly different from other therapeutic modes (p = 0 < 0.0001). Histology showed that the mice treated with phage did not develop pneumonia.

CONCLUSION

Phage therapy is effective against haematogenous MDRSA infection. Thus, it can be explored as an alternative treatment method.

Safety, Tolerability, and Pharmacokinetics of MEDI4893, an Investigational, Extended-Half-Life, Anti-Staphylococcus aureus Alpha-Toxin Human Monoclonal Antibody, in Healthy Adults

MEDI4893 is an investigational immunoglobulin G1(κ) monoclonal antibody that specifically binds to and neutralizes alpha-toxin, a key Staphylococcus aureus virulence factor. A triple-amino-acid substitution, M252Y/S254T/T256E, was engineered into the MEDI4893 Fc region to extend its serum half-life. A phase 1, double-blind, dose escalation study was designed to evaluate the safety, tolerability, pharmacokinetics, anti-alpha-toxin-neutralizing activity, and antidrug antibody (ADA) response of MEDI4893 following a single intravenous infusion in healthy adults 18 to 65 years of age. Thirty-three subjects were randomly assigned to receive MEDI4893 at 225 mg (n = 3), 750 mg (n = 3), 2,250 mg (n = 8), or 5,000 mg (n = 12) or placebo (n = 7) and were followed for 360 days. Adverse events were mild or moderate in severity; none were serious. The MEDI4893 peak serum concentration increased dose proportionally from 77.2 μg/ml (225-mg dose) to 1,784 μg/ml (5,000-mg dose). The area under the concentration-time curve from 0 to 360 days also increased dose proportionally, from 4,840 μg · day/ml (225-mg dose) to 91,493 μg · day/ml (5,000-mg dose), indicating linear pharmacokinetics. MEDI4893's terminal half-life was estimated to be 80 to 112 days, which is approximately 4-fold longer than the half-lives of other human immunoglobulin G antibodies. The alpha-toxin-neutralizing activity in serum correlated highly with the MEDI4893 concentrations in serum. Three adults transiently tested positive for ADA on day 151, but this did not have an impact on MEDI4893 serum concentrations or the MEDI4893 safety profile; no subjects exhibited serum ADA at the study end. These data support the continued development of MEDI4893 for the prevention of S. aureus-mediated pneumonia. (This study has been registered at ClinicalTrials.gov under identifier NCT02296320.)

Getting to zero: Reduction in the incidence of multidrug-resistant organism infections using an integrated infection control protocol in an intensive care unit

Environmental cleaning is a vital component of infection control. We describe the use of an integrated infection control protocol in an intensive care unit and its influence on multidrug-resistant organism infection rates. Sustained reductions in multidrug-resistant organism infections can be achieved if individual processes and weaknesses in intensive care unit environments are identified and addressed in a systematic and comprehensive manner.

Telavancin activity tested against a collection of Staphylococcus aureus isolates causing pneumonia in hospitalized patients in the United States (2013-2014)

Telavancin is approved in the United States and Europe for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia caused by Staphylococcus aureus. This study provides a current in vitro activity analysis for telavancin and comparators against 1353 United States S. aureus causing pneumonia in hospitalized patients during 2013-2014. Telavancin was found to exhibit potent activity (MIC₉₀, 0.06μg/mL; 16-fold more active than vancomycin or linezolid) against all S. aureus isolates, including the HABP subset, multidrug-resistant isolates, and those less susceptible to vancomycin.