Attributable Mortality of Healthcare-Associated Infections Due to Multidrug-Resistant Gram-Negative Bacteria and Methicillin-Resistant Staphylococcus Aureus

Preventing New Gram-negative Resistance Through Beta-lactam De-escalation in Hospitalized Patients With Sepsis: A Retrospective Cohort Study

BACKGROUND

Whether antibiotic de-escalation reduces the risk of subsequent antibiotic resistance is uncertain. We sought to determine if beta-lactam (BL) antibiotic de-escalation is associated with decreased incidence of new Gram-negative resistance in hospitalized patients with sepsis.

METHODS

In a retrospective cohort study, patients with sepsis who were treated with at least 3 consecutive days of BL antibiotics, the first 2 days of which were with a broad-spectrum BL agent defined as a spectrum score (SS) of ≥7 were enrolled. Patients were grouped into three categories: (1) de-escalation of beta-lactam spectrum score (BLSS), (2) no change in BLSS, or (3) escalation of BLSS. The primary outcome was the isolation of a new drug-resistant Gram-negative bacteria from a clinical culture within 60 days of cohort entry. Fine-Gray proportional hazards regression modeling while accounting for in-hospital death as a competing risk was performed.

FINDINGS

Six hundred forty-four patients of 7742 (8.3%) patients developed new gram-negative resistance. The mean time to resistance was 23.7 days yielding an incidence rate of 1.85 (95% confidence interval [CI]: 1.71-2.00) per 1000 patient-days. The lowest incidence rate was observed in the de-escalated group 1.42 (95% CI: 1.16-1.68) per 1000 patient-days. Statistically significant reductions in the development of new gram-negative resistance were associated with BL de-escalation compared to no-change (hazards ratio (HR) 0.59 [95% CI: .48-.73]).

CONCLUSIONS

De-escalation was associated with a decreased risk of new resistance development compared to no change. This represents the largest study to date showing the utility of de-escalation in the prevention of antimicrobial resistance.

Decolonization and Pathogen Reduction Approaches to Prevent Antimicrobial Resistance and Healthcare-Associated Infections

Antimicrobial resistance in healthcare-associated bacterial pathogens and the infections they cause are major public health threats affecting nearly all healthcare facilities. Antimicrobial-resistant bacterial infections can occur when colonizing pathogenic bacteria that normally make up a small fraction of the human microbiota increase in number in response to clinical perturbations. Such infections are especially likely when pathogens are resistant to the collateral effects of antimicrobial agents that disrupt the human microbiome, resulting in loss of colonization resistance, a key host defense. Pathogen reduction is an emerging strategy to prevent transmission of, and infection with, antimicrobial-resistant healthcare-associated pathogens. We describe the basis for pathogen reduction as an overall prevention strategy, the evidence for its effectiveness, and the role of the human microbiome in colonization resistance that also reduces the risk for infection once colonized. In addition, we explore ideal attributes of current and future pathogen-reducing approaches.

Long-term gut colonization with ESBL-producing Escherichia coli in participants without known risk factors from the southeastern United States

We evaluated gut carriage of extended spectrum beta lactamase producing Enterobacteriaceae (ESBL-E) in southeastern U.S. residents without recent in-patient healthcare exposure. Study enrollment was January 2021-February 2022 in Athens, Georgia, U.S. and included a diverse population of 505 adults plus 50 child participants (age 0-5). Based on culture-based screening of stool samples, 4.5% of 555 participants carried ESBL-Es. This is slightly higher than reported in studies conducted 2012-2015, which found carriage rates of 2.5-3.9% in healthy U.S. residents. All ESBL-E confirmed isolates (n=25) were identified as Escherichia coli. Isolates belonged to 11 sequence types, with 48% classified as ST131. Ninety six percent of ESBL-E isolates carried a blaCTX-M gene. Isolated ESBL-Es frequently carried virulence genes as well as multiple classes of antibiotic resistance genes. Long-term colonization was common, with 64% of ESBL-E positive participants testing positive when rescreened three months later. One participant yielded isolates belonging to two different E. coli sequence types that carried blaCTX-M-1 genes on near-identical plasmids, suggesting intra-gut plasmid transfer. Isolation of E. coli on media without antibiotics revealed that ESBL-E. coli typically made up a minor fraction of the overall gut E. coli population, although in some cases they were the dominant strain. ESBL-E carriage was not associated with a significantly different stool microbiome composition. However, some microbial taxa were differentially abundant in ESBL-E carriers. Together, these results suggest that a small subpopulation of US residents are long-term, asymptomatic carriers of ESBL-Es, and may serve as an important reservoir for community spread of these ESBL genes.

Different evolution of S. aureus methicillin-resistant and methicillin-susceptible infections, Argentina

Staphylococcus aureus-(SA) is widespread among healthcare-associated-(HA) and the community-associated-(CA) infections. However, the contributions of MRSA and MSSA to the SA overall burden remain unclear. In a nationally-representative-survey conducted in Argentina, 668 SA clinical isolates from 61 hospitals were examined in a prospective, cross-sectional, multicenter study in April 2015. The study aimed to analyze MRSA molecular epidemiology, estimate overall SA infection incidence (MSSA, MRSA, and genotypes) in community-onset (CO: HACO, Healthcare-Associated-CO and CACO, Community-Associated-CO) and healthcare-onset (HO: HAHO, Healthcare-associated-HO) infections, stratified by age groups. Additionally temporal evolution was estimated by comparing this study's (2015) incidence values with a previous study (2009) in the same region. Erythromycin-resistant-MSSA and all MRSA strains were genetically typed. The SA total-infections (TI) overall-incidence was 49.1/100,000 monthly-visits, 25.1 and 24.0 for MRSA and MSSA respectively (P = 0.5889), in April 2015. In adults with invasive-infections (INVI), MSSA was 15.7 and MRSA was 11.8 (P = 0.0288), 1.3-fold higher. HA SA infections, both MSSA and MRSA, surpassed CA infections by over threefold. During 2009-2015, there was a significant 23.4 % increase in the SA infections overall-incidence, mainly driven by MSSA, notably a 54.2 % increase in INVI among adults, while MRSA infection rates remained stable. The MSSA rise was accompanied by increased antimicrobial resistance, particularly to erythromycin, linked to MSSA-CC398-t1451-ermT + -IEC+-pvl- emergence. The SA-infections rise was primarily attributed to community-onset-infections (37.3 % and 62.4 % increase for TI and INVI, respectively), particularly HACO-MSSA and HACO-MRSA in adults, as well as CACO-MSSA. The main CA-MRSA-PFGE-typeN-ST30-SCCmecIVc-PVL+/- clone along with other clones (USA300-ST8-IV-LV-PVL+/-, PFGE-typeDD-ST97-IV- PVL-) added to rather than replaced CA-MRSA-PFGE-typeI-ST5-SCCmecIVa-PVL+/- clone in HA invasive-infections. They also displaced clone HA-MRSA-PFGE-typeA-ST5-SCCmecI, mainly in HAHO infections. The overall-burden of SA infections is rising in Argentina, driven primarily by community-onset MSSA, particularly in adults, linked to increased erythromycin-resistance and MSSA-CC398-t1451-ermT + -IEC+-pvl- emergence. Novel knowledge and transmission-control strategies are required for MSSA.

Clinical and epidemiological characteristics of multi-drug resistant Enterobacterales isolated from King Fahad Hospital of the University, AlKhobar, Saudi Arabia

Multi-drug resistant (MDR) Enterobacterales remain a major clinical problem. Infections caused by carbapenem-resistant strains are particularly difficult to treat. This study aimed to assess the clinical and epidemiological characteristics of MDR Enterobacterales isolates. A total of 154 non-repetitive clinical isolates, including Escherichia coli (n = 66), Klebsiella pneumoniae (n = 70), and other Enterobacterales (n = 18), were collected from the Diagnostic Microbiology Laboratory at King Fahad Hospital of the University. Most E. coli isolates were collected from urine specimens (n = 50, 75.8%) and resistance against the third and fourth-generation cephalosporins (ceftriaxone, ceftazidime, cefixime, and cefepime) and fluoroquinolones (ciprofloxacin and levofloxacin) was assessed. Clonal relatedness analysis using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) revealed two clones (E. coli A and B), each comprising two strains. Most K. pneumoniae samples were collected from respiratory specimens (27.1%, 20 samples), and the strains showed overall resistance to most of the antimicrobials tested (54%‒100%). Moreover, clonal-relatedness analysis using ERIC-PCR revealed seven major clones of K. pneumoniae. These findings suggest nosocomial transmission among some identical strains and emphasize the importance of strict compliance with infection prevention and control policies and regulations. Environmental reservoirs could facilitate this indirect transmission, which needs to be investigated.

Methicillin Resistant Staphylococcus aureus: Molecular Mechanisms Underlying Drug Resistance Development and Novel Strategies to Combat

Antimicrobial resistance (AMR) represents a major threat to global health. Infection caused by Methicillin-resistant Staphylococcus aureus (MRSA) is one of the well-recognized global public health problem globally. In some regions, as many as 90% of S. aureus infections are reported to be MRSA, which cannot be treated with standard antibiotics. WHO reports indicated that MRSA is circulating in every province worldwide, significantly increasing the risk of death by 64% compared to drug-sensitive forms of the infection which is attributed to its antibiotic resistance. The emergence and spread of antibiotic-resistant MRSA strains have contributed to its increased prevalence in both healthcare and community settings. The resistance of S. aureus to methicillin is due to expression of penicillin-binding protein 2a (PBP2a), which renders it impervious to the action of β-lactam antibiotics including methicillin. The other is through the production of beta-lactamases. Although the treatment options for MRSA are limited, there are promising alternatives to antibiotics to combat the infections. Innovative therapeutic strategies with wide range of activity and modes of action are yet to be explored. The review highlights the global challenges posed by MRSA, elucidates the mechanisms underlying its resistance development, and explores mitigation strategies. Furthermore, it focuses on alternative therapies such as bacteriophages, immunotherapy, nanobiotics, and antimicrobial peptides, emphasizing their synergistic effects and efficacy against MRSA. By examining these alternative approaches, this review provides insights into the potential strategies for tackling MRSA infections and combatting the escalating threat of AMR. Ultimately, a multifaceted approach encompassing both conventional and novel interventions is imperative to mitigate the impact of MRSA and ensure a sustainable future for global healthcare.

Pharmacokinetics of YK-1169 in healthy subjects and pharmacokinetic/pharmacodynamic analysis by Monte Carlo simulation

OBJECTIVE

This study (NCT05588531) aimed to evaluate the safety and pharmacokinetics of cefepime-avibactam (YK-1169) in healthy Chinese subjects and explore the optimal regimen for treating carbapenem-resistant Klebsiella pneumoniae (CRKP) based on the pharmacokinetic/pharmacodynamic evaluation.

METHODS

YK-1169 single-ascending doses (0.5, 1.25, 2.5 or 3.75 g, 2-h infusion) and multiple doses (2.5 or 3.75 g every 8 h [q8h], 2-h infusion) given for 7 days were evaluated in pharmacokinetic studies. Subjects were randomized to receive cefepime (2 g), avibactam (0.5 g) or YK-1169 (2.5 g) to assess drug-drug interactions. The minimum inhibitory concentrations (MICs) of YK-1169 were determined by the broth microdilution method. Monte Carlo simulation was used to evaluate 10 different dose regimens.

RESULTS

Cefepime and avibactam both showed a linear pharmacokinetic profile. No accumulation was found after multiple doses. The cefepime Cmax,ss and AUC0-∞,ss were 9.20 and 16.0 μg/mL, 407.2 and 659.45 μg·h/mL in the 2.5 and 3.75 g multiple-dose groups, respectively. The avibactam Cmax,ss and AUC0-∞,ss were 0.545 and 0.837 μg/mL, 53.31 and 79.55 μg·h/mL in the 2.5 and 3.75 g multiple-dose groups, respectively. Cefepime and avibactam did not affect each other's pharmacokinetics. No serious adverse events occurred. All regimens achieved 90% probability of target attainment (PTA) goals when the MIC was ≤8 mg/L. The regimens of 2.5 (q8h, 2-h infusion), 3.75 (q8h, 2-, 3- and 4-h infusions) and 7.5 g (24-h continuous infusion) reached a 90% cumulative fraction of response.

CONCLUSION

YK-1169 had good antibacterial activity against CRKP and could be an option for CRKP infections. The regimen of 2.5 g q8h intravenously guttae (ivgtt) 2 h should be considered in future clinical trials.

Active Surveillance of Antimicrobial Resistance and Carbapenemase-Encoding Genes According to Sites of Care and Age Groups in Mexico: Results from the INVIFAR Network

We analyzed the antimicrobial resistance (AMR) data of 6519 clinical isolates of Escherichia coli (n = 3985), Klebsiella pneumoniae (n = 775), Acinetobacter baumannii (n = 163), Pseudomonas aeruginosa (n = 781), Enterococcus faecium (n = 124), and Staphylococcus aureus (n = 691) from 43 centers in Mexico. AMR assays were performed using commercial microdilution systems (37/43) and the disk diffusion susceptibility method (6/43). The presence of carbapenemase-encoding genes was assessed using PCR. Data from centers regarding site of care, patient age, and clinical specimen were collected. According to the site of care, the highest AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from ICU patients. In contrast, in A. baumannii, higher AMR was observed in isolates from hospitalized non-ICU patients. According to age group, the highest AMR was observed in the ≥60 years age group for E. coli, E. faecium, and S. aureus, and in the 19-59 years age group for A. baumannii and P. aeruginosa. According to clinical specimen type, a higher AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from blood specimens. The most frequently detected carbapenemase-encoding gene in E. coli was blaNDM (84%).

Redox Impact on Bacterial Macromolecule: A Promising Avenue for Discovery and Development of Novel Antibacterials

Antibiotic resistance in bacteria has remained a serious public health concern, resulting in substantial deaths and morbidity each year. Factors such as mutation and abuse of currently available antibiotics have contributed to the bulk of the menace. Hence, the introduction and implementation of new therapeutic strategies are imperative. Of these strategies, data supporting the role of reactive oxygen species (ROS) in bacterial lethality are intriguing, with several antimicrobials, including antibiotics such as fluoroquinolones, β-lactams, and aminoglycosides, as well as natural plant compounds, being remarkably implicated. Following treatment with ROS-inducing antimicrobials, ROS such as O₂^•-, ^•OH, and H₂O₂ generated in bacteria, which the organism is unable to detoxify, damage cellular macromolecules such as proteins, lipids, and nucleic acids and results in cell death. Despite the unique mechanism of action of ROS-inducing antibacterials and significant studies on ROS-mediated means of bacterial killing, the field remains a topical one, with contradicting viewpoints that require frequent review. Here, we appraised the antibacterial agents (antibiotics, natural and synthetic compounds) implicated in ROS generation and the safety concerns associated with their usage. Further, background information on the sources and types of ROS in bacteria, the mechanism of bacterial lethality via oxidative stress, as well as viewpoints on the ROS hypothesis undermining and solidifying this concept are discussed.

New antimicrobial treatment options for severe Gram-negative infections

PURPOSE OF REVIEW

This review will provide rationale for the development of new antibiotics to treat severe or multidrug-resistant (MDR) Gram-negative infections. It will also provide an overview of recently approved and pipeline antibiotics for severe/MDR Gram-negative infections.

RECENT FINDINGS

MDR Gram-negative infections are recognized as critical threats by global and national organizations and carry a significant morbidity and mortality risk. Increasing antibiotic resistance amongst Gram-negative bacteria, including carbapenem-resistant Acinetobacter baumannii , extended-spectrum β-lactamase-producing Enterobacterales, carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa , with difficult-to-treat-resistance has made both empiric and definitive treatment of these infections increasingly problematic. In recent years, several antibiotics have been approved for treatment of MDR Gram-negative infections and ongoing clinical trials are poised to provide additional options to clinicians' armamentarium. These agents include various β-lactam/β-lactamase inhibitor combinations, eravacycline, plazomicin and cefiderocol.

SUMMARY

Severe/MDR Gram-negative infections continue to be important infections due to their impact on patient outcomes, especially in critically ill and immunocompromised hosts. The availability of new antibiotics offers an opportunity to improve empiric and definitive treatment of these infections.

Meeting the Unmet Need in the Management of MDR Gram-Positive Infections with Oral Bactericidal Agent Levonadifloxacin

Levonadifloxacin (intravenous) and its oral prodrug alalevonadifloxacin are broad-spectrum antibacterial agents developed for the treatment of difficult-to-treat infections caused by multidrug-resistant Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus, atypical bacteria, anaerobic bacteria, and biodefence pathogens as well as Gram-negative bacteria. Levonadifloxacin has a well-defined mechanism of action involving a strong affinity for DNA gyrase as well as topoisomerase IV. Alalevonadifloxacin with widely differing solubility and oral bioavailability has pharmacokinetic profile identical to levonadifloxacin. Unlike existing MRSA drugs such as vancomycin and linezolid, which cause unfavorable side effects like nephrotoxicity, bone-marrow toxicity, and muscle toxicity, levonadifloxacin/alalevonadifloxacin has demonstrated superior safety and tolerability features with no serious adverse events. Levonadifloxacin/alalevonadifloxacin could be a useful weapon in the battle against infections caused by resistant microorganisms and could be a preferred antibiotic of choice for empirical therapy in the future.

Evaluating the Effectiveness of Hospital Antiseptics on Multidrug-Resistant Acinetobacter baumannii: Understanding the Relationship between Microbicide and Antibiotic Resistance

Acinetobacter baumannii hospital infections are difficult to treat due to the rapid emergence of multidrug-resistant (MDR) strains. In addition, A. baumannii can survive in numerous adverse environments, including in the presence of common hospital antiseptics. We hypothesized that in addition to accumulating drug resistance determinants, MDR A. baumannii strains also accumulate mutations that allow for greater microbicide tolerance when compared to pan-susceptible (PS) strains. To test this hypothesis, we compared the survival of five MDR and five PS patient isolates when exposed to bleach, ethanol, quaternary ammonium compounds, chlorhexidine gluconate, and povidone. We evaluated bacteria in a free-living planktonic state and under biofilm conditions. Each disinfectant eliminated 99.9% of planktonic bacteria, but this was not the case for bacterial biofilms. Next, we characterized strains for the presence of the known microbicide-resistance genes cepA, qacEΔ1, qacE, and qacA. MDR strains did not survive more than PS strains in the presence of microbicides, but microbicide-resistant strains had higher survival rates under some conditions. Interestingly, the PS strains were more likely to possess microbicide-resistance genes. Microbicide resistance remains an important topic in healthcare and may be independent of antimicrobial resistance. Hospitals should consider stricter isolation precautions that take pan-susceptible strains into account.

Mortality, Length of Stay, and Healthcare Costs Associated With Multidrug-Resistant Bacterial Infections Among Elderly Hospitalized Patients in the United States

BACKGROUND

This study reports estimates of the healthcare costs, length of stay, and mortality associated with infections due to multidrug-resistant bacteria among elderly individuals in the United States.

METHODS

We conducted a retrospective cohort analysis of patients aged ≥65 admitted for inpatient stays in the Department of Veterans Affairs healthcare system between 1/2007-12/2018. We identified those with positive cultures for multidrug-resistant bacteria and matched each infected patient to ≤10 control patients. We then performed multivariable regression models to estimate the attributable cost and mortality due to the infection. We also constructed multistate models to estimate the attributable length of stay due to the infection. Finally, we multiplied these pathogen-specific attributable cost, length of stay, and mortality estimates by national case counts from hospitalized patients in 2017.

RESULTS

Our cohort consisted of 87 509 patients with infections and 835 048 matched controls. Costs were higher for hospital-onset invasive infections, with attributable costs ranging from $22 293 (95% confidence interval: $19 101-$24 485) for methicillin-resistant Staphylococcus aureus (MRSA) to $57 390 ($34 070-$80 710) for carbapenem-resistant (CR) Acinetobacter. Similarly, for hospital-onset invasive infections, attributable mortality estimates ranged from 14.2% (12.2-16.2%) for MRSA to 24.1% (12.1-36.0%) for CR Acinetobacter. The aggregate cost of these infections was an estimated $1.9 billion ($1.3 billion-$2.5 billion) with 11 852 (8719-14 985) deaths and 448 224 (354 513-541 934) inpatient days in 2017.

CONCLUSIONS

Efforts to prevent these infections due to multidrug-resistant bacteria could save a significant number of lives and healthcare resources.

Engineering a photosynthetic bacteria-incorporated hydrogel for infected wound healing

Treating wounds with multidrug-resistant bacterial infections remains a huge and arduous challenge. In this work, we prepared a "live-drug"-encapsulated hydrogel dressing for the treatment of multidrug-resistant bacterial infections and full-thickness skin incision repair. Our live dressing was comprised of photosynthetic bacteria (PSB) and extracellular matrix (ECM) gel with photothermal, antibacterial and antioxidant properties, as well as good cytocompatibility and blood compatibility. More interestingly, live PSB could be regarded as not only photothermal agents but also as anti-inflammatory agents to promote wound healing owing to their antioxidant metabolites. In vitro and in vivo studies showed that the PSB hydrogel not only had a high killing rate against methicillin-resistant Staphylococcus aureus (MRSA) but it also accelerated collagen deposition and granulation tissue formation by promoting cell proliferation and migration, which significantly promoted skin tissue regeneration and wound healing. We believe that the large-scale production of PSB Gel-based therapeutic dressings has the advantages of easy use and promising clinical applications. STATEMENT OF SIGNIFICANCE: Rapid wound healing and the treatment of bacterial infections have always been the two biggest challenges in the field of wound care. We prepared a "live drug" dressing by encapsulating photosynthetic bacteria into an extracellular matrix hydrogel to sterilize the wound and promote wound healing. First, photosynthetic bacteria are not only a photothermal agent for photothermal wound sterilization, but also possess the anti-inflammatory capacity to enhance wound healing due to their antioxidant metabolites. Second, the extracellular matrix hydrogel is rich in a variety of growth factors and nutrients to promote cell migration and accelerate wound healing. Third, photosynthetic bacteria are not only green and non-toxic, but also can be obtained on a large scale, which facilitates manufacturing and clinical transformation.

Antibiotic Resistance Patterns and Association with the Influenza Season in the United States: A Multicenter Evaluation Reveals Surprising Associations Between Influenza Season and Resistance in Gram-negative Pathogens

Background

Viral infections are often treated with empiric antibiotics due to suspected bacterial coinfections, leading to antibiotic overuse. We aimed to describe antibiotic resistance (ABR) trends and their association with the influenza season in ambulatory and inpatient settings in the United States.

Methods

We used the BD Insights Research Database to evaluate antibiotic susceptibility profiles in 30-day nonduplicate bacterial isolates collected from patients >17 years old at 257 US healthcare institutions from 2011 to 2019. We investigated ABR in Gram-positive (Staphylococcus aureus and Streptococcus pneumoniae) and Gram-negative (Enterobacterales [ENT], Pseudomonas aeruginosa [PSA], and Acinetobacter baumannii spp [ACB]) bacteria expressed as the proportion of isolates not susceptible ([NS], intermediate or resistant) and resistance per 100 admissions (inpatients only). Antibiotics included carbapenems (Carb), fluoroquinolones (FQ), macrolides, penicillin, extended-spectrum cephalosporins (ESC), and methicillin. Generalized estimating equations models were used to evaluate monthly trends in ABR outcomes and associations with community influenza rates.

Results

We identified 8 250 860 nonduplicate pathogens, including 154 841 Gram-negative Carb-NS, 1 502 796 Gram-negative FQ-NS, 498 012 methicillin-resistant S aureus (MRSA), and 44 131 NS S pneumoniae. All S pneumoniae rates per 100 admissions (macrolide-, penicillin-, and ESC-NS) were associated with influenza rates. Respiratory, but not nonrespiratory, MRSA was also associated with influenza. For Gram-negative pathogens, influenza rates were associated with the percentage of FQ-NS ENT, FQ-NS PSA, and Carb-NS ACB.

Conclusions

Our study showed expected increases in rates of ABR Gram-positive and identified small but surprising increases in ABR Gram-negative pathogens associated with influenza activity. These insights may help inform antimicrobial stewardship initiatives.

Association between antibiotic resistance in intensive care unit (ICU)-acquired infections and excess resource utilization: Evidence from Spain, Italy, and Portugal

BACKGROUND

Intensive care unit (ICU)-acquired infections with antibiotic-resistant bacteria have been associated with substantial health and economic costs. Moreover, southern Europe has historically reported high levels of antimicrobial resistance.

OBJECTIVES

We estimated the attributable economic burden of ICU-acquired infections due to resistant bacteria based upon hospital excess length of stay (LOS) in a selected sample of southern European countries.

METHODS

We studied a cohort of adult patients admitted to the ICU who developed an ICU-acquired infection related to an invasive procedure in a sample of Spanish, Italian, and Portuguese hospitals between 2008 and 2016, using data from The European Surveillance System (TESSy) released by the European Centers for Disease Control (ECDC). We analyzed the association between infections with selected antibiotic-resistant bacteria of public health importance and excess LOS using regression, matching, and time-to-event methods. We controlled for several confounding factors as well as time-dependent biases. We also computed the associated economic burden of excess resource utilization for each selected country.

RESULTS

In total, 13,441 patients with at least 1 ICU-acquired infection were included in the analysis: 4,106 patients (30.5%) were infected with antimicrobial-resistant bacteria, whereas 9,335 patients (69.5%) were infected with susceptible bacteria. The unadjusted association between resistance status and excess LOS was 7 days (95% CI, 6.13-7.87; P < .001). Fully adjusted models yielded significantly lower estimates: 2.76 days (95% CI, 1.98-3.54; P < .001) in the regression model, 2.60 days (95% CI, 1.66-3.55; P < .001) in the genetic matching model, and a hazard ratio of 1.15 (95% CI, 1.11-1.19; P < .001) in the adjusted Cox regression model. These estimates, alongside the prevalence of resistance, translated into direct hospitalization attributable costs per ICU-acquired infection of 5,224€ (95% CI, 3,691-6,757) for Spain, 4,461€ (95% CI, 1,948-6,974) for Portugal, and 4,320€ (95% CI, 1,662-6,977) for Italy.

CONCLUSIONS

ICU-acquired infections associated with antibiotic-resistant bacteria are substantially associated with a 15% increase in excess LOS and resource utilization in 3 southern European countries. However, failure to appropriately control for significant confounders inflates estimates by ∼2.5-fold.

Direct antimicrobial susceptibility testing (AST) from positive blood cultures using Microscan system for early detection of bacterial resistance phenotypes

Antimicrobial Susceptibility Testing is mandatory for Bloodstream Infections management in order to establish appropriate antimicrobial therapy. Herein we evaluated new approach based on AST results directly from positive blood cultures, using Microscan WA to carry out rapid phenotypical profile of antibiotic resistance. Our investigations allow to reduce time versus traditional results.

Low Proportion of Linezolid and Daptomycin Resistance Among Bloodborne Vancomycin-Resistant Enterococcus faecium and Methicillin-Resistant Staphylococcus aureus Infections in Europe

Vancomycin-resistant Enterococcus faecium (VREF) and methicillin-resistant Staphylococcus aureus (MRSA) are associated with significant health burden. We investigated linezolid and daptomycin resistance among VREF and MRSA in the EU/EEA between 2014 and 2018. Descriptive statistics and multivariable logistic regression were used to analyze 6,949 VREF and 35,131 MRSA blood isolates from patients with bloodstream infection. The population-weighted mean proportion of linezolid resistance in VREF and MRSA between 2014 and 2018 was 1.6% (95% CI 1.33–2.03%) and 0.28% (95% CI 0.32–0.38%), respectively. Daptomycin resistance in MRSA isolates was similarly low [1.1% (95% CI 0.75–1.6%)]. On the European level, there was no temporal change of daptomycin and linezolid resistance in MRSA and VREF. Multivariable regression analyses showed that there was a higher likelihood of linezolid and daptomycin resistance in MRSA (aOR: 2.74, p < 0.001; aOR: 2.25, p < 0.001) and linezolid in VREF (aOR: 1.99, p < 0.001) compared to their sensitive isolates. The low proportion of linezolid and daptomycin resistance in VREF and MRSA suggests that these last-resort antibiotics remain effective and will continue to play an important role in the clinical management of these infections in Europe. However, regional and national efforts to contain antimicrobial resistance should continue to monitor the trend through strengthened surveillance that includes genomic surveillance for early warning and action.

Biocidal Resistance in Clinically Relevant Microbial Species: A Major Public Health Risk

Antimicrobial resistance is one of the greatest dangers to public health of the 21st century, threatening the treatment and prevention of infectious diseases globally. Disinfection, the elimination of microbial species via the application of biocidal chemicals, is essential to control infectious diseases and safeguard animal and human health. In an era of antimicrobial resistance and emerging disease, the effective application of biocidal control measures is vital to protect public health. The COVID-19 pandemic is an example of the increasing demand for effective biocidal solutions to reduce and eliminate disease transmission. However, there is increasing recognition into the relationship between biocide use and the proliferation of Antimicrobial Resistance species, particularly multidrug-resistant pathogens. The One Health approach and WHO action plan to combat AMR require active surveillance and monitoring of AMR species; however, biocidal resistance is often overlooked. ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens and numerous fungal species have demonstrated drug and biocidal resistance where increased patient mortality is a risk. Currently, there is a lack of information on the impact of biocide application on environmental habitats and ecosystems. Undoubtedly, the excessive application of disinfectants and AMR will merge to result in secondary disasters relating to soil infertility, loss of biodiversity and destruction of ecosystems.

Characterization of R-pyocin activity against Gram-positive pathogens for the first time with special focus on Staphylococcus aureus

AIM

This study is aimed at characterization of both antimicrobial and anti-biofilm activity of R-pyocin from clinical Pseudomonas aeruginosa against Gram-positive pathogens including Staphylococcus aureus.

METHODS AND RESULTS

Pyocinogenic P. aeruginosa was detected using reverse-side method, and pyocinogeny typing was confirmed using revised-spotting method. Transmission electron microscopy (TEM) was used for morphological characterization of R-pyocin and for detection of changes in membrane of R-pyocin-treated S. aureus. SDS-PAGE analysis was used for detection of the molecular weight of R-pyocin protein-subunits and Poisson-killing-distribution assay for burst-size calculation. Lipotechoic-acid (LTA) adsorption-assay was used to confirm whether LTA in Gram-positive bacteria served as R-pyocin receptor. Moreover, R-pyocin production at 10-60°C was assessed herein. Host-range of activity of R-pyocin was tested against antimicrobial resistant (AMR) pathogens. The anti-biofilm activity of R-pyocin was detected against sensitive bacterial strains. Chemical, enzymatic, pH and thermo-stability of R-pyocin were evaluated. TEM micrographs revealed a typical morphology of myotailocins indicating the production of R-pyocin designated as RPU15. TEM revealed pores formation in S. aureus membrane, and bacteriophage-like plaques were obvious on plates of R-pyocin-treated S. aureus. R-pyocin activity was neutralized by LTA of S. aureus and Listeria monocytogenes. Pseudomonas aeruginosa PU15 produced ~428 non-inducible R-pyocin particles. RPU15 sheath and tube protein-subunits exhibited a molecular weight of 38 and 23 kDa, respectively. RPU15 possessed activity against S. aureus, L. monocytogenes, Bacillus cereus and Candida albicans and reduced biofilm-biomasses of tested AMR strains.

CONCLUSION

Our results show the potential therapeutic use of R-pyocin due to its effectiveness on tested bacterial biofilms.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study that investigates antimicrobial and anti-biofilm activity of R-pyocin activity against S. aureus. R-pyocin shows new phenomenon of bacteriophage-like plaques. Our findings represent a future therapeutic agent targeting both methicillin-resistant and vancomycin-resistant S. aureus.

Expanding an Economic Evaluation of the Veterans Affairs (VA) Methicillin-resistant Staphylococcus aureus (MRSA) Prevention Initiative to Include Prevention of Infections From Other Pathogens

BACKGROUND

In October 2007, Veterans Affairs (VA) launched a nationwide effort to reduce methicillin-resistant Staphylococcus aureus (MRSA) transmission called the National MRSA Prevention Initiative. Although the initiative focused on MRSA, recent evidence suggests that it also led to a significant decrease in hospital-onset (HO) gram-negative rod (GNR) bacteremia, vancomycin-resistant Enterococci (VRE), and Clostridioides difficile infections. The objective of this analysis was to evaluate the cost-effectiveness and the budget impact of the initiative taking into account MRSA, GNR, VRE, and C. difficile infections.

METHODS

We developed an economic model using published data on the rate of MRSA hospital-acquired infections (HAIs) and HO-GNR bacteremia in the VA from October 2007 to September 2015, estimates of the attributable cost and mortality of these infections, and the costs associated with the intervention obtained through a microcosting approach. We explored several different assumptions for the rate of infections that would have occurred if the initiative had not been implemented. Effectiveness was measured in life-years (LYs) gained.

RESULTS

We found that during fiscal years 2008-2015, the initiative resulted in an estimated 4761-9236 fewer MRSA HAIs, 1447-2159 fewer HO-GNR bacteremia, 3083-3602 fewer C. difficile infections, and 2075-5393 fewer VRE infections. The initiative itself was estimated to cost $561 million over this 8-year period, whereas the cost savings from prevented MRSA HAIs ranged from $165 to $315 million and from prevented HO-GNR bacteremia, CRE and C. difficile infections ranged from $174 to $200 million. The incremental cost-effectiveness of the initiative ranged from $12 146 to $38 673/LY when just including MRSA HAIs and from $1354 to $4369/LY when including the additional pathogens. The overall impact on the VA's budget ranged from $67 to$195 million.

CONCLUSIONS

An MRSA surveillance and prevention strategy in VA may have prevented a substantial number of infections from MRSA and other organisms. The net increase in cost from implementing this strategy was quite small when considering infections from all types of organisms. Including spillover effects of organism-specific prevention efforts onto other organisms can provide a more comprehensive evaluation of the costs and benefits of these interventions.

Comparative Effectiveness of Switching to Daptomycin Versus Remaining on Vancomycin Among Patients With Methicillin-resistant Staphylococcus aureus (MRSA) Bloodstream Infections

BACKGROUND

Patients with methicillin-resistant Staphylococcus aureus bloodstream infections (MRSA BSI) usually receive initial treatment with vancomycin but may be switched to daptomycin for definitive therapy, especially if treatment failure is suspected. Our objective was to evaluate the effectiveness of switching from vancomycin to daptomycin compared with remaining on vancomycin among patients with MRSA BSI.

METHODS

Patients admitted to 124 Veterans Affairs Hospitals who experienced MRSA BSI and were treated with vancomycin during 2007-2014 were included. The association between switching to daptomycin and 30-day mortality was assessed using Cox regression models. Separate models were created for switching to daptomycin any time during the first hospitalization and for switching within 3 days of receiving vancomycin.

RESULTS

In total, 7411 patients received vancomycin for MRSA BSI. Also, 606 (8.2%) patients switched from vancomycin to daptomycin during the first hospitalization, and 108 (1.5%) switched from vancomycin to daptomycin within 3 days of starting vancomycin. In the multivariable analysis, switching to daptomycin within 3 days was significantly associated with lower 30-day mortality (hazards ratio [HR] = 0.48; 95% confidence interval [CI]: .25, .92). However, switching to daptomycin at any time during the first hospitalization was not significantly associated with 30-day mortality (HR: 0.87; 95% CI: .69, 1.09).

CONCLUSIONS

Switching to daptomycin within 3 days of initial receipt of vancomycin is associated with lower 30-day mortality among patients with MRSA BSI. This benefit was not seen when the switch occurred later. Future studies should prospectively assess the benefit of early switching from vancomycin to other anti-MRSA antibiotics.

Exploring the practice, confidence and educational needs of hospital pharmacists in reviewing antimicrobial prescribing: a cross-sectional, nationwide survey

BACKGROUND

Antimicrobial stewardship (AMS) programs are usually limited in resources and scope. Therefore, wider engagement of hospital pharmacists in reviewing antimicrobial orders is necessary to ensure appropriate prescribing. We assessed hospital pharmacists' self-reported practice and confidence in reviewing antimicrobial prescribing, and their knowledge in making AMS interventions.

METHODS

We conducted an Australia-wide, cross-sectional survey in October 2017. A link to the online survey was emailed to hospital pharmacists via the Society of Hospital Pharmacists of Australia. Factors associated with higher knowledge scores were explored using linear regression models.

RESULTS

There were 439 respondents, of whom 272 (61.7%) were from metropolitan public hospitals. Pharmacists were more likely to assess the appropriateness of intravenous, broad-spectrum or restricted antibiotics than narrow-spectrum, oral antibiotics within 24-72 h of prescription; p < 0.001. Fifty percent or fewer respondents were confident in identifying AMS interventions related to dose optimization based on infection-specific factors, bug-drug mismatch, and inappropriate lack of spectra of antimicrobial activity. The median knowledge score (correct answers to knowledge questions) was 6 out of 9 (interquartile range, 5-7); key gaps were noted in antimicrobials' anaerobic spectrum, beta-lactam allergy assessment and dosing in immunocompromised patients. Clinical practice in inpatient areas, registration for 3-5 years and receipt of recent AMS education were associated with higher knowledge scores. More interactive modes of education delivery were preferred over didactic modes; p ≤ 0.01.

CONCLUSION

Gaps in practice, confidence and knowledge among hospital pharmacists were identified that could inform the design of educational strategies to help improve antimicrobial prescribing in Australian hospitals.

Overview on the role of heavy metals tolerance on developing antibiotic resistance in both Gram-negative and Gram-positive bacteria

Environmental health is a critical concern, continuously contaminated by physical and biological components (viz., anthropogenic activity), which adversely affect on biodiversity, ecosystems and human health. Nonetheless, environmental pollution has great impact on microbial communities, especially bacteria, which try to evolve in changing environment. For instance, during the course of adaptation, bacteria easily become resistance to antibiotics and heavy metals. Antibiotic resistance genes are now one of the most vital pollutants, provided as a source of frequent horizontal gene transfer. In this review, the environmental cause of multidrug resistance (MDR) that was supposed to be driven by either heavy metals or combination of environmental factors was essentially reviewed, especially focussed on the correlation between accumulation of heavy metals and development of MDR by bacteria. This kind of correlation was seemed to be non-significant, i.e. paradoxical. Gram-positive bacteria accumulating much of toxic heavy metal (i.e. highly stress tolerance) were unlikely to become MDR, whereas Gram-negative bacteria that often avoid accumulation of toxic heavy metal by efflux pump systems were come out to be more prone to MDR. So far, other than antibiotic contaminant, no such available data strongly support the direct influence of heavy metals in bacterial evolution of MDR; combinations of factors may drive the evolution of antibiotic resistance. Therefore, Gram-positive bacteria are most likely to be an efficient member in treatment of industrial waste water, especially in the removal of heavy metals, perhaps inducing the less chance of antibiotic resistance pollution in the environment.

A validated LC-MS/MS method for the simultaneous quantification of the novel combination antibiotic, ceftolozane-tazobactam, in plasma (total and unbound), CSF, urine and renal replacement therapy effluent: application to pilot pharmacokinetic studies

OBJECTIVES

Novel treatment options for some carbapenem-resistant Gram-negative pathogens have been identified by the World Health Organization as being of the highest priority. Ceftolozane-tazobactam is a novel cephalosporin-beta-lactamase inhibitor combination antibiotic with potent bactericidal activity against the most difficult-to-treat multi-drug resistant and extensively drug resistant Gram-negative pathogens. This study aimed to develop and validate a liquid chromatography - tandem mass spectrometry method for the simultaneous quantification of ceftolozane and tazobactam in plasma (total and unbound), renal replacement therapy effluent (RRTE), cerebrospinal fluid (CSF) and urine.

METHODS

Analytes were separated using mixed-mode chromatography with an intrinsically base-deactivated C18 column and a gradient mobile phase consisting of 0.1% formic acid, 10 mM ammonium formate and acetonitrile. The analytes and internal standards were detected using rapid ionisation switching between positive and negative modes with simultaneous selected reaction monitoring.

RESULTS

A quadratic calibration was obtained for plasma (total and unbound), RRTE and CSF over the concentration range of 1-200 mg/L for ceftolozane and 0.5-100 mg/L for tazobactam, and for urine the concentration range of 10-2,000 mg/L for ceftolozane and 5-1,000 mg/L for tazobactam. For both ceftolozane and tazobactam, validation testing for matrix effects, precision and accuracy, specificity and stability were all within the acceptance criteria of ±15%.

CONCLUSIONS

This methodology was successfully applied to one pilot pharmacokinetic study in infected critically ill patients, including patients receiving renal replacement therapy, and one case study of a patient with ventriculitis, where all patients received ceftolozane-tazobactam.

Risk Factors of Multidrug-Resistant Bacteria in Lower Respiratory Tract Infections: A Systematic Review and Meta-Analysis

Background

Multidrug-resistant (MDR) bacteria are the main cause of lower respiratory tract infections (LRTIs) with high mortality. The purpose of this study is to identify the risk factors associated with MDR by performing a systematic review and meta-analysis.

Methods

PubMed, EMBASE (via Ovid), and Cochrane Library were systematically searched for studies on the risk factors for MDR bacteria in LRTIs as of November 30, 2019. Literature screening, data abstraction, and quality assessment of the eligible studies were performed independently by two researchers.

Results

A total of 3,607 articles were retrieved, of which 21 articles representing 20 cohort studies published in English were included after title/abstract and full-text screening. Among the 21 articles involving 7,650 patients and 1,360 MDR organisms, ten reported the risk factors for MDR Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), ten for MDR GNB, and one for MDR GPB. The meta-analysis results suggested that prior antibiotic treatment, inappropriate antibiotic therapy, chronic lung disease, chronic liver disease and cerebral disease, prior MDR and PA infection/colonization, recent hospitalization, longer hospitalization stay, endotracheal tracheostomy and mechanical ventilation, tube feeding, nursing home residence, and higher disease severity score were independent risk factors for MDR bacteria.

Conclusions

This review identified fourteen clinical factors that might increase the risk of MDR bacteria in patients with LRTIs. Clinicians could take into account these factors when selecting antibiotics for patients and determine whether coverage for MDR bacteria is required. More well-designed studies are needed to confirm the various risk factors for MDR bacteria in the future.

Multidrug-resistant gram-negative organisms and association with 1-year mortality, readmission, and length of stay in Veterans with spinal cord injuries and disorders

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The goal of this study was to assess the impact of multidrug resistant gram-negative organisms (MDRGNOs) on outcomes in those with SCI/D.

SETTING

VA SCI System of Care, Department of Veterans Affairs, United States.

METHODS

Multidrug resistance (MDR) was defined as being non-susceptible to ≥1 antibiotic in ≥3 antibiotic classes. Multivariable cluster-adjusted regression models were fit to assess the association of MDRGNOs with 1-year mortality, 30-day readmission, and postculture length of stay (LOS) stratified by case setting patients. Only the first culture per patient during the study period was included.

RESULTS

A total of 8,681 individuals with SCI/D had a culture with gram-negative bacteria during the study period, of which 33.0% had a MDRGNO. Overall, 954 (10.9%) died within 1 year of culture date. Poisson regression showed that MDR was associated with 1-year mortality among outpatients (IRR: 1.28, 95% CI, 1.06-1.54) and long-term care patients (OR: 2.06, 95% CI, 1.28-3.31). MDR significantly impacted postculture LOS in inpatients, as evidenced by a 10% longer LOS in MDR vs. non-MDR (IRR: 1.10, 95% CI, 1.02-1.19). MDR was not associated with increased 30-day readmission.

CONCLUSIONS

MDRGNOs are prevalent in SCI/D and MDR may result in poor outcomes. Further attention to prevention of infections, antibiotic stewardship, and management are warranted in this population.

Methicillin-resistant Staphylococcus aureus Colonization and Pre- and Post-hospital Discharge Infection Risk

Background

The Department of Veterans Affairs implemented an active surveillance program for methicillin-resistant Staphylococcus aureus (MRSA) in 2007 in which acute care inpatients are tested for MRSA carriage on admission, unit-to-unit transfer, and discharge. Using these data, we followed patients longitudinally to estimate the difference in infection rates for those who were not colonized, those who were colonized on admission (importers), and those who acquired MRSA during their stay. We examined MRSA infections that occurred prior to discharge and at 30, 90, 180, and 365 days after discharge.

Methods

We constructed a dataset of 985626 first admissions from January 2008 through December 2015 who had surveillance tests performed for MRSA carriage. We performed multivariable Cox proportional hazards and logistic regression models to examine the relationship between MRSA colonization status and infection.

Results

The MRSA infection rate across the predischarge and 180-day postdischarge time period was 5.5% in importers and 7.0% in acquirers without a direct admission to the intensive care unit (ICU) and 11.4% in importers and 11.7% in acquirers who were admitted directly to the ICU. The predischarge hazard ratio for MRSA infection was 29.6 (95% confidence interval [CI], 26.5-32.9) for importers and 28.8 (95% CI, 23.5-35.3) for acquirers compared to those not colonized. Fully 63.9% of all MRSA pre- and postdischarge infections among importers and 61.2% among acquirers occurred within 180 days after discharge.

Conclusions

MRSA colonization significantly increases the risk of subsequent MRSA infection. In addition, a substantial proportion of MRSA infections occur after discharge from the hospital.

Proactive infectious disease consultation at the time of blood culture collection is associated with decreased mortality in patients with methicillin-resistant Staphylococcus aureus bacteremia: A retrospective cohort study

In most existing studies on the impact of infectious disease (ID) specialty care on bloodstream infections, ID consultations were started upon request or mandatory after notification of positive blood cultures; however, initial antibiotic therapy had already been administrated at that time by attending physicians. This study aimed to assess the impact of early ID consultation at the time of blood culture collection on therapeutic management and outcome of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. This retrospective cohort study investigated all patients with MRSA bacteremia (MRSAB) from 2011 to 2018. Proactive ID consultations were available 24 h per day, 7 days per week and obtained upon request by attending physicians, and patients were classed as having early ID consultation (at the time of blood culture collection) or late ID consultation (after notification of positive blood cultures), or none. A total of 55 first MRSAB episodes were included. In the ID consultation group, a significantly higher proportion of patients were treated for more than 14 days, and significantly more echocardiography and follow-up blood cultures were performed. Moreover, patients in the ID consultation group were hospitalized for a significantly shorter period overall. With respect to cost, we noted a possible association between ID consultation and lower hospital charges. Furthermore, relative to late ID consultation, patients receiving early ID consultation were more likely to receive appropriate empirical therapy and had significantly lower all-cause in-hospital mortality (odds ratio, 0.034; 95% confidence interval [CI], 0.0002-0.51; p = 0.015) and long-term mortality (hazard ratio, 0.17; 95% CI, 0.033-0.83; p = 0.028).

Flexible Hierarchical Wraps Repel Drug-Resistant Gram-Negative and Positive Bacteria

Healthcare acquired infections are a major human health problem, and are becoming increasingly troublesome with the emergence of drug resistant bacteria. Engineered surfaces that reduce the adhesion, proliferation, and spread of bacteria have promise as a mean of preventing infections and reducing the use of antibiotics. To address this need, we created a flexible plastic wrap that combines a hierarchical wrinkled structure with chemical functionalization to reduce bacterial adhesion, biofilm formation, and the transfer of bacteria through an intermediate surface. These hierarchical wraps were effective for reducing biofilm formation of World Health Organization-designated priority pathogens Gram positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram negative Pseudomonas aeruginosa by 87 and 84%, respectively. In addition, these surfaces remain free of bacteria after being touched by a contaminated surface with Gram negative E. coli. We showed that these properties are the result of broad liquid repellency of the engineered surfaces and the presence of reduced anchor points for bacterial adhesion on the hierarchical structure. Such wraps are fabricated using scalable bottom-up techniques and form an effective cover on a variety of complex objects, making them superior to top-down and substrate-specific surface modification methods.

MRSA dynamic circulation between the community and the hospital setting: New insights from a cohort study

Dissemination of methicillin-resistant-Staphylococcus aureus/(MRSA) is a worldwide concern both in hospitals [healthcare-associated-(HA)-MRSA] and communities [community-associated-(CA)-MRSA]. Knowledge on when and where MRSA colonization is acquired and what clones are involved is necessary, to focus efforts for prevention of hospital-acquired MRSA-infections.

METHODS

A prospective/longitudinal cohort study was performed in eight Argentina hospitals (Cordoba/ October-December/2014). Surveillance cultures for MRSA (nose-throat-inguinal) were obtained on admission and at discharge. MRSA strains were genetically typed as CA-MRSA_G and HA-MRSA_G genotypes.

RESULTS

Overall, 1419 patients were screened and 534 stayed at hospital for ≥3 days. S. aureus admission prevalence was 30.9% and 4.2% for MRSA. Overall MRSA acquisition rate was 2.3/1000 patient-days-at-risk with a MRSA acquisition prevalence of 1.96% (95%CI: 1.0%-3.4%); 3.2% of patients were discharged back to community with MRSA. CA-MRSA_G accounted for 84.6% of imported, 100.0% of hospital-acquired and 94% of discharged MRSA strains. Most imported and acquired MRSA strains belonged to two major epidemic CA-MRSA clones spread in Argentina: PFGEtypeI-ST5-IVa-t311-PVL⁺ and PFGEtypeN/ST30-IVc-t019-PVL⁺.

CONCLUSIONS

CA-MRSA clones, particularly ST5-IV-PVL⁺ and ST30-IV-PVL⁺, with main reservoir in the community, not only enter but also are truly acquired within hospital, causing healthcare-associated-hospital-onset infections, having a transmission capacity greater or similar than HA-MRSA_G. This information is essential to develop appropriate MRSA infection prevention-control programs, considering hospital and community.

Attributable mortality from extensively drug-resistant gram-negative infections using propensity-matched tracer antibiotic algorithms

BACKGROUND

Tracer antibiotic algorithms using administrative data were investigated to estimate mortality attributable to extensively drug-resistant gram-negative infections (GNIs).

METHODS

Among adult inpatients coded for GNIs, colistin cases and 2 comparator cohorts (non-carbapenem β-lactams or carbapenems) treated for ≥4 consecutive days, or died while receiving the antibiotic, were separately propensity score-matched (1:2). Attributable mortality was the in-hospital mortality difference among propensity-matched groups. Infection characteristics and sepsis severity influences on attributable mortality were examined. Algorithm accuracy was assessed by chart review.

RESULTS

Of 232,834 GNIs between 2010 and 2013 at 79 hospitals, 1,023 per 3,350 (30.5%) colistin and 9,188 per 105,641 (8.7%) β-lactam (non-carbapenem) comparator cases died. Propensity-matched colistin and β-lactam case mortality was 29.2% and 16.6%, respectively, for an attributable mortality of 12.6% (95% confidence interval 10.8-14.4%). Attributable mortality varied from 11.0% (7.5%-14.7%) for urinary to 15.5% (12.6%-18.4%) for respiratory (P < .0001), and 4.6% (2.1%-7.4%) for early (≤4 days) to 16.6% (14.3%-18.9%) for late-onset infections (P < .0001). Attributable mortality decreased to 7.5% (5.6%-9.4%) using a carbapenem comparator cohort but increased 9-fold in patients coded for severe sepsis or septic shock (P < .0001). Our colistin algorithm had a positive predictive value of 60.4% and sensitivity of 65.3%.

CONCLUSIONS

Mortality attributable to treatment-limiting resistance during GNIs varied considerably by site, onset, and severity of infection.

Assessment of rapid direct E-test on positive blood culture for same-day antimicrobial susceptibility

INTRODUCTION

Early and appropriated antimicrobial therapy showed to positively impact on the clinical improvement of septic patients. The aim of this study was to evaluate E-test methodology to obtain rapid results of antimicrobial susceptibility, starting directly from blood culture bottles positive to Gram-negative monomicrobial flora.

MATERIALS AND METHODS

One hundred and five blood culture samples positive to Gram-negative rods at the microscopic examination were collected. Bacterial identification from early subculture on blood agar after 4 h incubation and rapid direct E-test from blood culture broth were performed on every sample. Antibiotics MIC were achieved after 5-6 h of incubation. Resulting MIC values were compared with those obtained with reference E-test from the overnight subculture. Categorical agreement (CA) and essential agreement (EA) were evaluated.

RESULTS

Comparison between rapid direct E-test and reference E-test showed CA ranging from 95.1 to 100 % and 88.2 to 100 % for Enterobacteriaceae (EB) and for non-fermenting Gram-negative bacilli, respectively. Rapid direct E-test showed an overall EA of 80.1 %, revealing different EA rates for the tested antibiotics. Among carbapenemase-producing EB, CA of 87.5 % and EA of 75.5 % for MP were achieved.

DISCUSSION

The same-day communication of the antimicrobial susceptibility represents an important challenge in the multidrug-resistance era. Despite not being able to anticipate actual MIC values, the rapid direct E-test may be useful to obtain preliminary AST results in 5-6 h, especially if used in association with phenotypic or genotypic tests to identify the main resistance mechanisms.

Novel Antibiotics for Multidrug-Resistant Gram-Positive Microorganisms

Increasing multidrug-resistance to Gram-positive pathogens, particularly to staphylococci, enterococci and streptococci, is a major problem, resulting in significant morbidity, mortality and healthcare costs. In recent years, only a small number of novel antibiotics effective against Gram-positive bacteria has been approved. This review will discuss the current evidence for novel branded antibiotics that are highly effective in the treatment of multidrug-resistant infections by Gram-positive pathogens, namely ceftobiprole, ceftaroline, telavancin, oritavancin, dalbavancin, tedizolid, besifloxacin, delafloxacin, ozenoxacin, and omadacycline. The mechanism of action, pharmacokinetics, microbiological spectrum, efficacy and safety profile will be concisely presented. As for any emerging antibiotic agent, resistance is likely to develop against these highly effective antibiotics. Only through appropriate dosing, utilization and careful resistance development monitoring will these novel antibiotics continue to treat Gram-positive pathogens in the future.

Perceived differences between intensivists and infectious diseases consultants facing antimicrobial resistance: a global cross-sectional survey

To identify differences in perception on multi-drug-resistant (MDR) organisms and their management at intensive care units (ICU). A cross-sectional survey was conducted. A proposal addressing a pathogen priority list (PPL) for ICU, arising from the TOTEM study, was compared with a sample of global experts in infections in critically ill patients. The survey was responded by 129 experts. Globally, ESBL Enterobacteriaceae, followed by carbapenem-resistant Acinetobacter baumannii and carbapenem-resistant Klebsiella pneumoniae, were the main concerns. Some differences in opinion were identified between 63 (49%) ICU physicians (ICU/anesthesiology) and 43 (33%) infectious disease consultants (ID physicians/microbiologists). The pathogens most concerning in the ICU for intensivists were ESBL Enterobacteriaceae (38%) versus carbapenem-resistant A. baumannii (48.3%) for ID consultants, (p < 0.05). Increasing number of ID consultants over intensivists (26% vs 14%) reported difficulty in choosing initial therapy for carbapenem-resistant A. baumannii. For intensivists, the urgent measures to limit development of antibiotic resistance were headed by cohort measures (26.3%) versus increasing nurse/patient ratio (32.5%) for ID consultants, (p < 0.05). Regarding effectiveness to prevent MDR development and spread, education programs (42.4%) were the priority for intensivists versus external consultation (35.7%) for ID consultants. Finally, both groups agreed that carbapenem resistance was the most pressing concern (> 70%) regarding emerging resistance. Differences in priorities regarding organisms, infection control practices, and educational priorities were visualized between ID/clinical microbiologists and ICU/anesthesiologists. Multi-disciplinary collaboration is required to achieve best care for ICU patients with severe infections.

Multidrug-resistant Gram-negative Bacterial Bloodstream Infections in Children's Hospitals in Japan, 2010-2017

BACKGROUND

The risk factors of multidrug-resistant (MDR) Gram-negative bacilli (GNB) bloodstream infection (BSI) are not yet known in children. Our aim was to evaluate risk factors and outcomes associated with MDR GNB BSI in children.

METHODS

Patients with GNB BSI were enrolled between April 2010 and March 2017 at 8 children's hospitals in Japan. Clinical and microbiologic data were collected retrospectively. The risk factors and outcomes of MDR and non-MDR GNB BSI were compared.

RESULTS

In total, 629 GNB BSI episodes met the case definition. The median age and proportion of males were 2 years (interquartile range, 0.3-8.7) and 50.7%, respectively. An underlying disease was found in 94% of patients. The proportion of BSI cases that developed >48 hours after admission was 76.2%. MDR comprised 24.5% of BSI cases. The MDR rate did not change over time (P = 0.540). The effective coverage rate of the initial empiric therapy for the MDR and non-MDR BSI cases was 60.4% and 83.4%, respectively (P < 0.001). The all-cause mortality rate at 28 days for all BSI, MDR-BSI and non-MDR BSI cases was 10.7%, 13.6% and 9.7%, respectively (P = 0.167). MDR BSI was independently associated with cancer chemotherapy within 30 days (odds ratio [OR] 43.90), older age (OR 1.05) and admission to the neonatal ward (OR 0.019).

CONCLUSIONS

One-fourth of GNB BSI cases were MDR. Cancer chemotherapy and older age were risk factors for MDR GNB BSI in children's hospitals. MDR did not increase the all-cause mortality rate.

National prevalence estimates for resistant Enterobacteriaceae and Acinetobacter species in hospitalized patients in the United States

OBJECTIVES

To determine antimicrobial nonsusceptibility rates for Enterobacteriaceae and Acinetobacter spp. in US hospitals.

METHODS

We analyzed antimicrobial susceptibilities of non-duplicate Enterobacteriaceae and Acinetobacter spp. isolates reported in 2017 from 375 US hospitals in the BD Insights Research Database. Logistic and Poisson regression modeling methods were used to estimate proportions of resistant isolates and rates per 1000 hospital admissions. National projections were generated based on raking (weighting) methods.

RESULTS

The nationwide proportions of resistant isolates in inpatients were an estimated 12.6%, 6.6%, and 1.2% for Enterobacteriaceae with extended-spectrum beta-lactamase (ESBL), multidrug resistant (MDR), and carbapenem-nonsusceptible (Carb-NS) phenotypes, respectively, and 42.4% and 34.5% for Acinetobacter spp. with MDR and Carb-NS phenotypes. Resistance varied by geographic region and hospital size/type. Estimated nationwide rates per 1000 hospital admissions ranged from a high of 7.1 for ESBL Enterobacteriaceae to a low of 0.3 for Carb-NS Acinetobacter spp. The estimated number of isolates occurring in US inpatients each year was 290,220 ESBL, 173,984 MDR, and 30,194 Carb-NS for Enterobacteriaceae and 12,274 MDR and 9,991 Carb-NS for Acinetobacter spp.

CONCLUSIONS

National prevalence estimates suggest high levels of antimicrobial resistance and a substantial number of patients with resistant Enterobacteriaceae and Acinetobacter spp. in US hospitals.

Analysis of the challenges in implementing guidelines to prevent the spread of multidrug-resistant gram-negatives in Europe

OBJECTIVE

The main objective of the study was to investigate major differences among European countries in implementing infection prevention and control (IPC) measures and reasons for reduced compliance.

DESIGN

An online survey including experts in IPC and a gap analysis were conducted to identify major limitations in implementing IPC guidelines.

SETTING

Europe.

MAIN OUTCOME MEASURES

Four areas were targeted: (1) healthcare structure, (2) finances, (3) culture and (4) education and awareness. Perceived compliance to IPC measures was classified as low (<50%), medium (50% to 80%) and high (>80%). Countries were classified in three regions: North-Western Europe (NWE), Eastern Europe (EE) and Southern Europe (SE).

RESULTS

In total, 482 respondents from 34 out of 44 (77.3%) European countries participated. Respondents reported availability of national guidelines to control multidrug-resistant Gram-negatives (MDR-GN) in 20 countries (58.0%). According to participants, compliance with IPC measures ranged from 17.8% (screening at discharge) to 96.0% (contact precautions). Overall, three areas were identified as critical for the compliance rate: (1) number of infection control staff, (2) IPC dedicated educational programmes and (3) number of clinical staff. Analysis of reasons for low compliance showed high heterogeneity among countries: participants from NWE and SE deemed the lack of educational programmes as the most important, while those from EE considered structural reasons, such as insufficient single bed rooms or lacking materials for isolation, as main contributors to the low compliance.

CONCLUSIONS

Although national guidelines to reduce the spread of MDR-GN are reported in the majority of the European countries, low compliance with IPC measures was commonly reported. Reasons for the low compliance are multifactorial and vary from region to region. Cross-country actions to reduce the spread of MDR-GN have to consider structural and cultural differences in countries. Locally calibrated interventions may be fruitful in the future.

Population Pharmacokinetic Analyses for Plazomicin Using Pooled Data from Phase 1, 2, and 3 Clinical Studies

Plazomicin is an aminoglycoside with activity against multidrug-resistant Enterobacteriaceae Plazomicin is dosed on a milligram-per-kilogram-of-body-weight basis and administered by a 30-min intravenous infusion every 24 h, with dose adjustments being made for renal impairment and a body weight (BW) of ≥125% of ideal BW. A population pharmacokinetic analysis was performed to identify patient factors that account for variability in pharmacokinetics and to determine if dose adjustments are warranted based on covariates. The analysis included 143 healthy adults and 421 adults with complicated urinary tract infection (cUTI), acute pyelonephritis, bloodstream infection, or hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia (HABP/VABP) from seven studies (phases 1 to 3). A three-compartment structural pharmacokinetic model with a zero-order rate constant for the intravenous infusion and linear first-order elimination kinetics best described the plasma concentration-time profiles. The base structural model included creatinine clearance (CL_CR) as a time-varying covariate for clearance. The covariates included age, BW, height, body surface area, body mass index, sex, race, and disease-related factors. The ranges of the α-, β-, and γ-phase half-lives for the analysis population were 0.328 to 1.58, 2.77 to 5.38, and 25.8 to 36.5 h, respectively. Total and renal clearances in a typical cUTI or HABP/VABP patient were 4.57 and 4.08 liters/h, respectively. Starting dose adjustments for CL_CR are sufficient for minimizing the variation in plasma exposure across patient populations; adjustments based on other covariates are not warranted. The results support initial dosing on a milligram-per-kilogram basis with adjustments for CL_CR and BW. Subsequent adjustments based on therapeutic drug management are recommended in certain subsets of patients, including the critically ill and renally impaired.

A snapshot of antimicrobial resistance in Mexico. Results from 47 centers from 20 states during a six-month period

Aim

We aimed to assess the resistance rates of antimicrobial-resistant, in bacterial pathogens of epidemiological importance in 47 Mexican centers.

Material and methods

In this retrospective study, we included a stratified sample of 47 centers, covering 20 Mexican states. Selected isolates considered as potential causatives of disease collected over a 6-month period were included. Laboratories employed their usual methods to perform microbiological studies. The results were deposited into a database and analyzed with the WHONET 5.6 software.

Results

In this 6-month study, a total of 22,943 strains were included. Regarding Gram-negatives, carbapenem resistance was detected in ≤ 3% in Escherichia coli, 12.5% in Klebsiella sp. and Enterobacter sp., and up to 40% in Pseudomonas aeruginosa; in the latter, the resistance rate for piperacillin-tazobactam (TZP) was as high as 19.1%. In Acinetobacter sp., resistance rates for cefepime, ciprofloxacin, meropenem, and TZP were higher than 50%. Regarding Gram-positives, methicillin resistance in Staphylococcus aureus (MRSA) was as high as 21.4%, and vancomycin (VAN) resistance reached up to 21% in Enterococcus faecium. Acinetobacter sp. presented the highest multidrug resistance (53%) followed by Klebsiella sp. (22.6%) and E. coli (19.4%).

Conclusion

The multidrug resistance of Acinetobacter sp., Klebsiella sp. and E. coli and the carbapenem resistance in specific groups of enterobacteria deserve special attention in Mexico. Vancomycin-resistant enterococci (VRE) and MRSA are common in our hospitals. Our results present valuable information for the implementation of measures to control drug resistance.

Alkyd resin based hydrophilic self-cleaning surface with self-refreshing behaviour as single step durable coating

Herein, we reported the photo-catalytic degradation/anti-bacterial property of Ag-doped ZnO nanoparticles (SDZO Nps) prepared by a facile gel-combustion technique and its self-cleaning/self-refreshing/self-disinfectant behaviour while on impregnating as pigment into the alkyd resin based coating. The influence of doping Ag (1% & 2%) with ZnO has been evaluated in terms of crystal structure, morphology, optical properties, etc. using X-ray diffraction analysis, Field Emission Scanning Electron Microscope, UV-Vis analysis, and Photoluminescence spectra. The photo-catalytic degradation of crystal violet solution by SDZO Nps is spectroscopically followed employing UV-Vis spectroscopy. From the obtained results, the rate of degradation of 1% SDZO Nps is found higher than that of other samples under sunlight illumination; degrading 1 mg of crystal violet in 30 min. Thus, implementing the synergic effect of nano ZnO and the doped Ag provides a suitable pathway for the development of high efficient photo-catalyst. Further, alkyd resin based self-cleaning coating is formulated using 1% SDZO Nps as pigment along with other additives; the contents are milled to form a homogeneous mixture by high energy ball milling technique. Crystal violet solution coated over dried alkyd coating gets decolorized on exposure to sunlight indicating the mineralization of pollutants and proves the fact that the as obtained coating possess self-cleaning nature. Besides the self-cleaning property, the coating exhibits self-refreshing property which is essential for the long lasting self-cleaning activity. Further, the disinfectant properties of 1% SDZO Nps and 1% SDZO Nps impregnated coating have been evaluated against gram negative Escherichia coli bacterial strain. The acquired experimental outcomes suggest the potential use of self-cleaning coating to keep the environment clean and hygienic economically.

Infections by multidrug-resistant Gram-negative Bacteria: What's new in our arsenal and what's in the pipeline?

The spread of multidrug-resistant bacteria is an ever-growing concern, particularly among Gram-negative bacteria because of their intrinsic resistance and how quickly they acquire and spread new resistance mechanisms. Treating infections caused by Gram-negative bacteria is a challenge for medical practitioners and increases patient mortality and cost of care globally. This vulnerability, along with strategies to tackle antimicrobial resistance development, prompts the development of new antibiotic agents and exploration of alternative treatment options. This article summarises the new antibiotics that have recently been approved for Gram-negative bacterial infections, looks down the pipeline at promising agents currently in phase I, II, or III clinical trials, and introduces new alternative avenues that show potential in combating multidrug-resistant Gram-negative bacteria.

A Recombinant Snake Cathelicidin Derivative Peptide: Antibiofilm Properties and Expression in Escherichia coli

The emergence of antimicrobial resistance among pathogenic microorganisms has been led to an urgent need for antibiotic alternatives. Antimicrobial peptides (AMPs) have been introduced as promising therapeutic agents because of their remarkable potentials. A new modified cathelicidin-BF peptide (Cath-A) with 34 amino acid sequences, represents the potential antimicrobial effects against methicillin-resistant Staphylococcus aureus (MRSA) with slight hemolytic and cytotoxic activities on eukaryotic cells. In this study, the effects of Cath-A on Acinetobacter baumannii, and Pseudomonas aeruginosa isolated from medical instruments were studied. Cath-A inhibited the growth of bacterial cells in the range of 8⁻16 μg/mL and 16-≥256 μg/mL for A. baumannii and P. aeruginosa, respectively. The peptide significantly removed the established biofilms. To display a representative approach for the cost-effective constructions of peptides, the recombinant Cath-A was cloned in the expression vector pET-32a(+) and transformed to Escherichia coli BL21. The peptide was expressed with a thioredoxin (Trx) sequence in optimum conditions. The recombinant peptide was purified with a Ni2+ affinity chromatography and the mature peptide was released after removing the Trx fusion protein with enterokinase. The final concentration of the partially purified peptide was 17.6 mg/L of a bacterial culture which exhibited antimicrobial activities. The current expression and purification method displayed a fast and effective system to finally produce active Cath-A for further in-vitro study usage.

Antimicrobial Resistance to Agents Used for Staphylococcus aureus Decolonization: Is There a Reason for Concern?

PURPOSE OF REVIEW

Chlorhexidine gluconate (CHG) and mupirocin are increasingly used for Staphylococcus aureus decolonization to prevent healthcare-associated infections; however, increased use of these agents has led to concerns for growing resistance and reduced efficacy. In this review, we describe current understanding of reduced susceptibility to CHG and mupirocin in S. aureus and their potential clinical implications.

RECENT FINDINGS

While emergence of S. aureus tolerant or resistant to topical antimicrobial agents used for decolonization is well described, the clinical impact of reduced susceptibility is not clear. Important challenges are that standardized methods of resistance testing and interpretation are not established, and the risk for selection for co- or cross-resistance using universal, as opposed to targeted decolonization, is unclear. Evidence continues to support S. aureus decolonization in certain patient groups, although further studies are needed to determine the long-term impact of CHG and mupirocin resistance on efficacy. Strategies to mitigate further development of reduced susceptibility and the consequences of selection pressures through universal decolonization on resistance will benefit from further investigation.

Host-Pathogen-Treatment Triad: Host Factors Matter Most in Methicillin-Resistant Staphylococcus aureus Bacteremia Outcomes

Previous studies have separately emphasized the importance of host, pathogen, and treatment characteristics in determining short-term or in-hospital mortality rates for patients with methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections. Less is known about the relative importance of these factors and their interactions in determining short-, medium-, and long-term mortality rates. This is an observational cohort study in which data for all patients admitted to the University of New Mexico (UNM) Health Sciences Center (HSC) between July 2002 and August 2013 with MRSA-positive blood cultures were recorded. We collected patients' demographics and treatment data, as well as data on genetic markers of the MRSA isolates. Outcomes of interest were determinants of short-term (within 30 days), medium-term (30 to 90 days), and long-term (>90 days) mortality rates. This study included 273 patients with MRSA bacteremia. Short-, medium-, and long-term mortality rates were 18.7%, 26.4%, and 48%, respectively. Thirty-day mortality rates were influenced by host variables and host-pathogen interaction characteristics. Pitt bacteremia scores, malignancy, and health care exposure contributed to 30- to 90-day mortality rates, while treatment duration of >4 weeks had a protective effect. Age remained a significant risk factor for death at >90 days, while admission leukocytosis was protective. Infection represented the most frequent cause of death for all three time frames; rates varied from 72.6% in the first 30 days and 60% for 30 to 90 days to 35.7% for >90 days (P = 0.003). Host characteristics affect short-, medium-, and long-term mortality rates for MRSA bloodstream infections more than do pathogen genetic markers and treatment factors.