Network of microbial and antibiotic interactions drive colonization and infection with multidrug-resistant organisms

An Insight into Rational Drug Design: The Development of In-House Azole Compounds with Antimicrobial Activity

Antimicrobial resistance poses a major threat to global health as the number of efficient antimicrobials decreases and the number of resistant pathogens rises. Our research group has been actively involved in the design of novel antimicrobial drugs. The blueprints of these compounds were azolic heterocycles, particularly thiazole. Starting with oxadiazolines, our research group explored, one by one, the other five-membered heterocycles, developing more or less potent compounds. An overview of this research activity conducted by our research group allowed us to observe an evolution in the methodology used (from inhibition zone diameters to minimal inhibitory concentrations and antibiofilm potential determination) correlated with the design of azole compounds based on results obtained from molecular modeling. The purpose of this review is to present the development of in-house azole compounds with antimicrobial activity, designed over the years by this research group from the departments of Pharmaceutical and Therapeutical Chemistry in Cluj-Napoca.

Impact of a Purified Microbiome Therapeutic on Abundance of Antimicrobial Resistance Genes in Patients With Recurrent Clostridioides difficile Infection

BACKGROUND

The gastrointestinal microbiota is an important line of defense against colonization with antimicrobial resistant (AR) bacteria. In this post hoc analysis of the phase 3 ECOSPOR III trial, we assessed impact of a microbiota-based oral therapeutic (fecal microbiota spores, live; VOWST Oral Spores [VOS], formerly SER-109]; Seres Therapeutics) compared with placebo, on AR gene (ARG) abundance in patients with recurrent Clostridioides difficile infection (rCDI).

METHODS

Adults with rCDI were randomized to receive VOS or placebo orally for 3 days following standard-of-care antibiotics. ARG and taxonomic profiles were generated using whole metagenomic sequencing of stool at baseline and weeks 1, 2, 8, and 24 posttreatment.

RESULTS

Baseline (n = 151) and serial posttreatment stool samples collected through 24 weeks (total N = 472) from 182 patients (59.9% female; mean age: 65.5 years) in ECOSPOR III as well as 68 stool samples obtained at a single time point from a healthy cohort were analyzed. Baseline ARG abundance was similar between arms and significantly elevated versus the healthy cohort. By week 1, there was a greater decline in ARG abundance in VOS versus placebo (P = .003) in association with marked decline of Proteobacteria and repletion of spore-forming Firmicutes, as compared with baseline. We observed abundance of Proteobacteria and non-spore-forming Firmicutes were associated with ARG abundance, while spore-forming Firmicutes abundance was negatively associated.

CONCLUSIONS

This proof-of-concept analysis suggests that microbiome remodeling with Firmicutes spores may be a potential novel approach to reduce ARG colonization in the gastrointestinal tract.

Chlorella-Loaded Antibacterial Microneedles for Microacupuncture Oxygen Therapy of Diabetic Bacterial Infected Wounds

Hypoxia and infection are urgent clinical problems in chronic diabetic wounds. Herein, living Chlorella-loaded poly(ionic liquid)-based microneedles (PILMN-Chl) are constructed for microacupuncture oxygen and antibacterial therapy against methicillin-resistant Staphylococcus aureus (MRSA)-infected chronic diabetic wounds. The PILMN-Chl can stably and continuously produce oxygen for more than 30 h due to the photosynthesis of the loaded self-supported Chlorella. By combining the barrier penetration capabilities of microneedles, the continuous and sufficient oxygen supply of Chlorella, and the sterilization activities of PIL, the PILMN-Chl can accelerate chronic diabetic wounds in vivo by topical targeted sterilization and hypoxia relief in deep parts of wounds. Thus, the self-oxygen produced microneedles modality may provide a promising and facile therapeutic strategy for treating chronic, hypoxic, and infected diabetic wounds.

Epidemiology and molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolated from neonatal intensive care units in General Hospital of Ningxia Medical University, China, 2017-2021

OBJECTIVES

This study aimed to retrospectively investigate the epidemiology and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates from neonatal intensive care units (NICU) between 2017 and 2021.

METHODS

The antibacterial susceptibility of all strains was assessed using the VITEK 2 compact system. The presence of antibiotic resistance, virulence genes, sequence types (STs), capsular (K) types, and the wzi genes was determined through polymerase chain reaction (PCR). Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI. Additionally, the virulence potential of peg344-positive strains was evaluated using the string test and mouse intraperitoneal infection models. Whole-genome sequencing was conducted on the DNB system and PacBio platforms.

RESULTS

A total of 46 CRKP isolates were collected during the study period. Out of these, 93.47% (43/46) were identified as CRKP strains belonging to the ST76-K10 type carrying blaNDM-5. It was observed that CRKP infection resulted in more severe clinical symptoms compared to CRKP colonization. Among the CRKP strains, a hypervirulent CRKP strain called KP-63, belonging to the ST23 type, was identified. This strain exhibited high mortality in the mouse infection model and was found to possess virulence genes. Genomic alignment analysis revealed a significant similarity between the virulence plasmid from KP-63 strain (pKP-63) and pK2044 from the hypervirulent K. pneumoniae strain NTUH-2044.

CONCLUSIONS

There has been a potential dissemination of ST76-K10 type CRKP carrying blaNDM-5 in the NICU at Ningxia Hospital. Neonatal CRKP infection has been found to cause more severe clinical symptoms than colonization. Furthermore, we have discovered a CR-hvKP strain of ST23 with serotype K1, which exhibits a significant resemblance in its virulent plasmid to pK2044. Therefore, it is crucial to enforce effective measures to restrict the spread and hinder the evolution of CRKP within the hospital.

Deconstructing the effects of stochasticity on transmission of hospital-acquired infections in ICUs

The inherent stochasticity in transmission of hospital-acquired infections (HAIs) has complicated our understanding of transmission pathways. It is particularly difficult to detect the impact of changes in the environment on acquisition rate due to stochasticity. In this study, we investigated the impact of uncertainty (epistemic and aleatory) on nosocomial transmission of HAIs by evaluating the effects of stochasticity on the detectability of seasonality of admission prevalence. For doing so, we developed an agent-based model of an ICU and simulated the acquisition of HAIs considering the uncertainties in the behaviour of the healthcare workers (HCWs) and transmission of pathogens between patients, HCWs, and the environment. Our results show that stochasticity in HAI transmission weakens our ability to detect the effects of a change, such as seasonality patterns, on acquisition rate, particularly when transmission is a low-probability event. In addition, our findings demonstrate that data compilation can address this issue, while the amount of required data depends on the size of the said change and the degree of uncertainty. Our methodology can be used as a framework to assess the impact of interventions and provide decision-makers with insight about the minimum required size and target of interventions in a healthcare facility.

Clinical Risk Scores to Predict Nonsusceptibility to Trimethoprim-Sulfamethoxazole, Fluoroquinolone, Nitrofurantoin, and Third-Generation Cephalosporin Among Adult Outpatient Episodes of Complicated Urinary Tract Infection

Background

Clinical risk scores were developed to estimate the risk of adult outpatients having a complicated urinary tract infection (cUTI) that was nonsusceptible to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolone, nitrofurantoin, or third-generation cephalosporin (3-GC) based on variables available on clinical presentation.

Methods

A retrospective cohort study (1 December 2017-31 December 2020) was performed among adult members of Kaiser Permanente Southern California with an outpatient cUTI. Separate risk scores were developed for TMP-SMX, fluoroquinolone, nitrofurantoin, and 3-GC. The models were translated into risk scores to quantify the likelihood of nonsusceptibility based on the presence of final model covariates in a given cUTI outpatient.

Results

A total of 30 450 cUTIs (26 326 patients) met the study criteria. Rates of nonsusceptibility to TMP-SMX, fluoroquinolone, nitrofurantoin, and 3-GC were 37%, 20%, 27%, and 24%, respectively. Receipt of prior antibiotics was the most important predictor across all models. The risk of nonsusceptibility in the TMP-SMX model exceeded 20% in the absence of any risk factors, suggesting that empiric use of TMP-SMX may not be advisable. For fluoroquinolone, nitrofurantoin, and 3-GC, clinical risk scores of 10, 7, and 11 predicted a ≥20% estimated probability of nonsusceptibility in the models that included cumulative number of prior antibiotics at model entry. This finding suggests that caution should be used when considering these agents empirically in patients who have several risk factors present in a given model at presentation.

Conclusions

We developed high-performing parsimonious risk scores to facilitate empiric treatment selection for adult outpatients with cUTIs in the critical period between infection presentation and availability of susceptibility results.

Synergistic effects of length of stay and prior MDRO carriage on the colonization and co-colonization of methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and carbapenemase-producing Enterobacterales across healthcare settings

OBJECTIVE

To characterize the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and carbapenemase-producing Enterobacterales (CPE) co-colonization and to compare risk factors between healthcare facility types.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a 3-year cross-sectional study among patients admitted to an acute-care hospital (ACH) and its 6 closely affiliated intermediate- and long-term care facilities (ILTCFs) in Singapore in June and July of 2014-2016.

METHODS

Specimens were concurrently collected from nares, axillae, and groins for MRSA detection, and from rectum or stool for VRE and CPE detection. Co-colonization was defined as having >1 positive culture of MRSA/VRE/CPE. Multinomial logistic regression was performed to determine predictors of co-colonization.

RESULTS

Of 5,456 patients recruited, 176 (3.2%) were co-colonized, with higher prevalence among patients in ITCFs (53 of 1,255, 4.2%) and the ACH (120 of 3,044, 3.9%) than LTCFs (3 of 1,157, 0.3%). MRSA/VRE was the most common type of co-colonization (162 of 5,456, 3.0%). Independent risk factors for co-colonization included male sex (odds ratio [OR], 1.96; 95% confidence interval [CI], 1.37-2.80), prior antibiotic therapy of 1-3 days (OR, 10.39; 95% CI, 2.08-51.96), 4-7 days (OR, 4.89; 95% CI, 1.01-23.68), >7 days (OR, 11.72; 95% CI, 2.81-48.85), and having an open wound (OR, 2.34; 95% CI, 1.66-3.29). Additionally, we detected the synergistic interaction of length of stay >14 days and prior multidrug-resistant organism (MDRO) carriage on co-colonization. Having an emergency surgery was a significant predictor of co-colonization in ACH patients, and we detected a dose-response association between duration of antibiotic therapy and co-colonization in ILTCF patients.

CONCLUSIONS

We observed common and differential risk factors for MDRO co-colonization across healthcare settings. This study has identified at-risk groups that merit intensive interventions, particularly patients with prior MDRO carriage and longer length of stay.

Interactions of microorganisms within a urinary catheter polymicrobial biofilm model

Biofilms are often polymicrobial in nature, which can impact their behavior and overall structure, often resulting in an increase in biomass and enhanced antimicrobial resistance. Using plate counts and locked nucleic acid/2'-O-methyl-RNA fluorescence in situ hybridization (LNA/2'OMe-FISH), we studied the interactions of four species commonly associated with catheter-associated urinary tract infections (CAUTI): Enterococcus faecalis, Escherichia coli, Candida albicans, and Proteus mirabilis. Eleven combinations of biofilms were grown on silicone coupons placed in 24-well plates for 24 h, 37°C, in artificial urine medium (AUM). Results showed that P. mirabilis was the dominant species and was able to inhibit both E. coli and C. albicans growth. In the absence of P. mirabilis, an antagonistic relationship between E. coli and C. albicans was observed, with the former being dominant. E. faecalis growth was not affected in any combination, showing a more mutualistic relationship with the other species. Imaging results correlated with the plate count data and provided visual verification of species undetected using the viable plate count. Moreover, the three bacterial species showed overall good repeatability SD (S_r ) values (0.1-0.54) in all combinations tested, whereas C. albicans had higher repeatability S_r values (0.36-1.18). The study showed the complexity of early-stage interactions in polymicrobial biofilms. These interactions could serve as a starting point when considering targets for preventing or treating CAUTI biofilms containing these species.

Clinical prediction models for multidrug-resistant organism colonisation or infection in critically ill patients: a systematic review protocol

INTRODUCTION

Multidrug-resistant organisms (MDROs) are pathogenic bacteria that are the leading cause of hospital-acquired infection which is associated with high morbidity and mortality rates in intensive care units, increasing hospitalisation duration and cost. Predicting the risk of MDRO colonisation or infection for critically ill patients supports clinical decision-making. Several models predicting MDRO colonisation or infection have been developed; however, owing to different disease scenarios, bacterial species and few externally validated cohorts in different prediction models; the stability and applicability of these models for MDRO colonisation or infection in critically ill patients are controversial. In addition, there are currently no standardised risk scoring systems to predict MDRO colonisation or infection in critically ill patients. The aim of this systematic review is to summarise and assess models predicting MDRO colonisation or infection in critically ill patients and to compare their predictive performance.

METHODS AND ANALYSIS

We will perform a systematic search of PubMed, Cochrane Library, CINAHL, Embase, Web of science, China National Knowledge Infrastructure and Wanfang databases to identify all studies describing the development and/or external validation of models predicting MDRO colonisation or infection in critically ill patients. Two reviewers will independently extract and review the data using the Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist; they will also assess the risk of bias using the Prediction Model Risk of Bias Assessment Tool. Quantitative data on model predictive performance will be synthesised in meta-analyses, as applicable.

ETHICS AND DISSEMINATION

Ethical permissions will not be required because all data will be extracted from published studies. We intend to publish our results in peer-reviewed scientific journals and to present them at international conferences on critical care.

PROSPERO REGISTRATION NUMBER

CRD42022274175.

Is shorter always better? The pros and cons of treating Gram-negative bloodstream infections with 7 days of antibiotics

Accumulating evidence from randomized controlled trials (RCTs) supports 7 days treatment for uncomplicated Gram-negative bacteraemia. However, some patient populations were not well represented in these RCTs, including critically ill patients, immunocompromised patients and those with MDR bacteria. In this debate document, we discuss the pros and cons for treating patients with Gram-negative bacteraemia with a 7 day antibiotic course. We surmise that the patients who were not well represented in the RCTs are probably those who have most to lose from the drawbacks of prolonged antibiotic courses, including adverse events, superinfections and resistance development. Treatment durations among these patients can be managed individually, with C-reactive protein or procalcitonin guidance or by clinical measures, and with care to discontinue antibiotics as soon as the patient recovers clinically from the infection.

Association of Exposure to High-risk Antibiotics in Acute Care Hospitals With Multidrug-Resistant Organism Burden in Nursing Homes

IMPORTANCE

Little is known about the contribution of hospital antibiotic prescribing to multidrug-resistant organism (MDRO) burden in nursing homes (NHs).

OBJECTIVES

To characterize antibiotic exposures across the NH patient's health care continuum (preceding health care exposure and NH stay) and to investigate whether recent antibiotic exposure is associated with MDRO colonization and room environment contamination at NH study enrollment.

DESIGN, SETTING, AND PARTICIPANTS

This is a secondary analysis of a prospective cohort study (conducted from 2013-2016) that enrolled NH patients and followed them up for as long as 6 months. The study was conducted in 6 NHs in Michigan among NH patients who were enrolled within 14 days of admission. Clinical metadata abstraction, multi-anatomical site screening, and room environment surveillance for MDROs were conducted at each study visit. Data were analyzed between May 2019 and November 2021.

EXPOSURES

Antibiotic data were abstracted from NH electronic medical records by trained research staff and characterized by class, route, indication, location of therapy initiation, risk for Clostridioides difficile infection (C diffogenic agents), and 2019 World Health Organization Access, Watch, and Reserve (AWARE) antibiotic stewardship framework categories.

MAIN OUTCOMES AND MEASURES

The primary outcomes were MDRO colonization and MDRO room environment contamination at NH study enrollment, measured using standard microbiology methods. Multivariable logistic regression was used to identify whether antibiotic exposure within 60 days was associated with MDRO burden at NH study enrollment. Additionally, antibiotic exposure data were characterized using descriptive statistics.

RESULTS

A total of 642 patients were included (mean [SD] age, 74.7 [12.2] years; 369 [57.5%] women; 402 [62.6%] White; median [IQR] NH days to enrollment, 6.0 [3.0-7.0]). Of these, 422 (65.7%) received 1191 antibiotic exposures: 368 (57.3%) received 971 hospital-associated prescriptions, and 119 (18.5%) received 198 NH-associated prescriptions. Overall, 283 patients (44.1%) received at least 1 C diffogenic agent, and 322 (50.2%) received at least 1 high-risk WHO AWARE antibiotic (watch or reserve agent). More than half of NH patients (364 [56.7%]) and room environments (437 [68.1%]) had MDRO-positive results at enrollment. In multivariable analysis, recent antibiotic exposure was positively associated with baseline MDRO colonization (odds ratio [OR], 1.70; 95% CI, 1.22-2.38) and MDRO environmental contamination (OR, 1.67; 95% CI, 1.17-2.39). Exploratory stratification by C diffogenic agent exposure increased the effect size (MDRO colonization: OR, 1.99; 95% CI, 1.33-2.96; MDRO environmental contamination: OR, 1.86; 95% CI, 1.24-2.79). Likewise, exploratory stratification by exposure to high-risk WHO AWARE antibiotics increased the effect size (MDRO colonization: OR, 2.32; 95% CI, 1.61-3.36; MDRO environmental contamination: OR, 1.86; 95% CI, 1.26-2.75).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that high-risk, hospital-based antibiotics are a potentially high-value target to reduce MDROs in postacute care NHs. This study underscores the potential utility of integrated hospital and NH stewardship programming on regional MDRO epidemiology.

High Acquisition Rate of Gram-Negative Multi-Drug Resistant Organism Colonization During Hospitalization: A Perspective from a High Endemic Setting

Objective

The aim of the study was to compare the rate of gram-negative multi-drug resistant organism (GN-MDRO) colonization at admission and during hospitalization and to describe the strains and antibiotic resistance genes acquired during hospitalization.

Methods

Rectal swabs were collected from patients hospitalized at the National Trauma Center (NTC), Mongolia, at the time of admission and after 14 days of hospitalization as has been detailed on our previous study. GN-MDRO antibiotic resistance was determined using EUCAST standards, and resistance genes were detected using multiplex PCR.

Results

A total of 158 patients were screened, and baseline colonization rate at admission was 29.1% (46/158). The rate went up to 69.9% (110/158) after 14 days of hospitalization (p<0.001). Of all participants, 74 patients (46.8%) screened GN-MDRO negative at admission acquired colonization by day 14. Other 36 patients (22.8%) maintained colonization that was screened positive at both time points. Only 38 patients (24.0%) remained free of GN-MDRO during hospitalization. There was a difference in GN-MDRO acquisition between these groups. Patients who were negative at admission acquired up to 3 GN-MDRO species, and there were 10 different species isolated. Reversely, patients who were screened positive at both time points had fairly homogenous isolates; up to 5 species of Enterobacterales were identified at admission and day 14 hospitalization. Overall, Enterobacterales were the dominant colonizers (61.4%, 97/158), and all Enterobacterales were resistant to cefotaxime as CTX-M resistance was our inclusion criteria.

Conclusion

GN-MDRO baseline colonization rate on admission was high and, alarmingly, doubled during hospitalization in the study area. Enterobacterales was the predominant colonizer and was highly resistant to 3rd generation cephalosporin. This data supports a need for an improved infection control policy including routine surveillance of the GN-MDROs and improved antibiotic stewardship program.

Novel strategies to diagnose prosthetic or native bone and joint infections

INTRODUCTION

Bone and Joint Infections (BJI) are medically important, costly and occur in native and prosthetic joints. Arthroplasties will increase significantly in absolute numbers over time as well as the incidence of Prosthetic Joint Infections (PJI). Diagnosis of BJI and PJI is sub-optimal. The available diagnostic tests have variable effectiveness, are often below standard in sensitivity and/or specificity, and carry significant contamination risks during the collection of clinical samples. Improvement of diagnostics is urgently needed.

AREAS COVERED

We provide a narrative review on current and future diagnostic microbiology technologies. Pathogen identification, antibiotic resistance detection, and assessment of the epidemiology of infections via bacterial typing are considered useful for improved patient management. We confirm the continuing importance of culture methods and successful introduction of molecular, mass spectrometry-mediated and next-generation genome sequencing technologies. The diagnostic algorithms for BJI must be better defined, especially in the context of diversity of both disease phenotypes and clinical specimens rendered available.

EXPERT OPINION

Whether interventions in BJI or PJI are surgical or chemo-therapeutic (antibiotics and bacteriophages included), prior sensitive and specific pathogen detection remains a therapy-substantiating necessity. Innovative tests for earlier and more sensitive and specific detection of bacterial pathogens in BJI are urgently needed.

Highly efficient enrichment and identification of pathogens using a herringbone microfluidic chip and by MALDI-TOF mass spectrometry

Bacterial infections cause considerable morbidity and expensive healthcare costs. The prescription of broad-spectrum antimicrobial drugs results in failure of treatment or overtreatment and exacerbates the spread of multidrug-resistant pathogens. There is an emergent demand for rapid and accurate methods to identify pathogens and conduct personalized therapy. Here, we develop a herringbone microfluidic chip integrated with vancomycin modified magnetic beads (herringbone-VMB microchip) to enrich pathogens. The enriched pathogens are identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The herringbone-VMB microchip applies passive mixing of bacterial samples by generating microvortices, which significantly enhances the interaction between bacteria and vancomycin modified magnetic beads and leads to more efficient enrichment compared to in-tube extraction. Four common pathogens in urinary tract infections are utilized to validate the method, and the capture efficiency of the bacteria from urine is up to 90%. The whole procedure takes 1.5 hours from enrichment to identification. This method shows potential in shortening the turnaround time in the clinical diagnosis of bacterial infections.

Comparison of criteria for determining appropriateness of antibiotic prescribing in nursing homes

BACKGROUND

Measuring the appropriateness of antibiotic prescribing in nursing homes remains a challenge. The revised McGeer criteria, which are widely used to conduct infection surveillance in nursing homes, were not designed to assess antibiotic appropriateness. The Loeb criteria were explicitly designed for this purpose but are infrequently used outside investigational studies. The extent to which the revised McGeer and Loeb criteria overlap and can be used interchangeably for tracking antibiotic appropriateness in nursing homes remains insufficiently studied.

METHODS

We conducted a cross-sectional chart review study in 5 Wisconsin nursing homes and applied the revised McGeer and Loeb criteria to all nursing home-initiated antibiotic treatment courses. Kappa (κ) statistics were employed to assess level of agreement overall and by treatment indications.

RESULTS

Overall, 734 eligible antibiotic courses were initiated in participating nursing homes during the study period. Of 734 antibiotic courses, 372 (51%) satisfied the Loeb criteria, while only 211 (29%) of 734 satisfied the revised McGeer criteria. Only 169 (23%) of 734 antibiotic courses satisfied both criteria, and the overall level of agreement between them was fair (κ = 0.35). When stratified by infection type, levels of agreement between the revised McGeer and Loeb criteria were moderate for urinary tract infections (κ = 0.45), fair for skin and soft-tissue infections (0.36), and slight for respiratory tract infections (0.17).

CONCLUSIONS

Agreement between the revised McGeer and Loeb criteria is limited, and nursing homes should employ the revised McGeer and Loeb criteria for their intended purposes. Studies to establish the best method for ongoing monitoring of antibiotic appropriateness in nursing homes are needed.

Evolution of the Gram-Negative Antibiotic Resistance Spiral over Time: A Time-Series Analysis

We followed up the interplay between antibiotic use and resistance over time in a tertiary-care hospital in Hungary. Dynamic relationships between monthly time-series of antibiotic consumption data (defined daily doses per 100 bed-days) and of incidence densities of Gram-negative bacteria (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Acinetobacter baumannii) resistant to cephalosporins or carbapenems were followed using vector autoregressive models sequentially built of time-series ending in 2015, 2016, 2017, 2018, and 2019. Relationships with Gram-negative bacteria as a group were fairly stable across years. At species level, association of cephalosporin use and cephalosporin resistance of E. coli was shown in 2015–2017, leading to increased carbapenem use in these years. Association of carbapenem use and carbapenem resistance, as well as of carbapenem resistance and colistin use in case of A. baumannii, were consistent throughout; associations in case of Klebsiella spp. were rarely found; associations in case of P. aeruginosa varied highly across years. This highlights the importance of temporal variations in the interplay between changes in selection pressure and occurrence of competing resistant species.

Prevalence and Risk Factors for Multidrug-Resistant Organisms Colonization in Long-Term Care Facilities Around the World: A Review

Elderly people confined to chronic care facilities face an increased risk of acquiring infections by multidrug-resistant organisms (MDROs). This review presents the current knowledge of the prevalence and risk factors for colonization by MDROs in long-term care facilities (LTCF), thereby providing a useful reference to establish objectives for implementing successful antimicrobial stewardship programs (ASPs). We searched in PubMed and Scopus for studies examining the prevalence of MDROs and/or risk factors for the acquisition of MDROs in LTCF. One hundred and thirty-four studies published from 1987 to 2020 were included. The prevalence of MDROs in LTCF varies between the different continents, where Asia reported the highest prevalence of extended-spectrum ß-lactamase (ESBL) Enterobacterales (71.6%), carbapenem resistant (CR) Enterobacterales (6.9%) and methicillin-resistant Staphylococcus aureus (MRSA) (25.6%) and North America the highest prevalence to MDR Pseudomonas aeruginosa (5.4%), MDR Acinetobacter baumannii (15.0%), vancomycin-resistant Enterococcus spp. (VRE) (4.0%), and Clostridioides difficile (26.1%). Furthermore, MDRO prevalence has experienced changes over time, with increases in MDR P. aeruginosa and extended spectrum ß-lactamase producing Enterobacterales observed starting in 2015 and decreases of CR Enterobacterales, MDR A. baumannii, VRE, MRSA and C. difficile. Several risk factors have been found, such as male sex, chronic wounds, the use of medical devices, and previous antibiotic use. The last of these aspects represents one of the most important modifiable factors for reducing colonization with MDROs through implementing ASPs in LTCF.

Antibiotic utilization in deceased organ donors

Antibiotic use in deceased organ donors has not been previously described. In a retrospective cohort of 440 donors, we found 427 (97%) received at least one antibiotic course, 312 (71%) received broad-spectrum antibiotics, and 61 (14%) received potentially redundant antibiotics during their terminal hospitalization, suggesting a need for stewardship.

The microbial network property as a bio-indicator of antibiotic transmission in the environment

Interspecies interaction is an essential mechanism for bacterial communities to develop antibiotic resistance via horizontal gene transfer. Nonetheless, how bacterial interactions vary along the environmental transmission of antibiotics and the underpinnings remain unclear. To address it, we explore potential microbial associations by analyzing bacterial networks generated from 16S rRNA gene sequences and functional networks containing a large number of antibiotic-resistance genes (ARGs). Antibiotic concentration decreased by more than 4000-fold along the environmental transmission chain from manure samples of swine farms to aerobic compost, compost-amended agricultural soils, and neighboring agricultural soils. Both bacterial and functional networks became larger in nodes and links with decreasing antibiotic concentrations, likely resulting from lower antibiotics stress. Nonetheless, bacterial networks became less clustered with decreasing antibiotic concentrations, while functional networks became more clustered. Modularity, a key topological property that enhances system resilience to antibiotic stress, remained high for functional networks, but the modularity values of bacterial networks were the lowest when antibiotic concentrations were intermediate. To explain it, we identified a clear shift from deterministic processes, particularly variable selection, to stochastic processes at intermediate antibiotic concentrations as the dominant mechanism in shaping bacterial communities. Collectively, our results revealed microbial network dynamics and suggest that the modularity value of association networks could serve as an important indicator of antibiotic concentrations in the environment.

Microbiota restoration reduces antibiotic-resistant bacteria gut colonization in patients with recurrent Clostridioides difficile infection from the open-label PUNCH CD study

BACKGROUND

Once antibiotic-resistant bacteria become established within the gut microbiota, they can cause infections in the host and be transmitted to other people and the environment. Currently, there are no effective modalities for decreasing or preventing colonization by antibiotic-resistant bacteria. Intestinal microbiota restoration can prevent Clostridioides difficile infection (CDI) recurrences. Another potential application of microbiota restoration is suppression of non-C. difficile multidrug-resistant bacteria and overall decrease in the abundance of antibiotic resistance genes (the resistome) within the gut microbiota. This study characterizes the effects of RBX2660, a microbiota-based investigational therapeutic, on the composition and abundance of the gut microbiota and resistome, as well as multidrug-resistant organism carriage, after delivery to patients suffering from recurrent CDI.

METHODS

An open-label, multi-center clinical trial in 11 centers in the USA for the safety and efficacy of RBX2660 on recurrent CDI was conducted. Fecal specimens from 29 of these subjects with recurrent CDI who received either one (N = 16) or two doses of RBX2660 (N = 13) were analyzed secondarily. Stool samples were collected prior to and at intervals up to 6 months post-therapy and analyzed in three ways: (1) 16S rRNA gene sequencing for microbiota taxonomic composition, (2) whole metagenome shotgun sequencing for functional pathways and antibiotic resistome content, and (3) selective and differential bacterial culturing followed by isolate genome sequencing to longitudinally track multidrug-resistant organisms.

RESULTS

Successful prevention of CDI recurrence with RBX2660 correlated with taxonomic convergence of patient microbiota to the donor microbiota as measured by weighted UniFrac distance. RBX2660 dramatically reduced the abundance of antibiotic-resistant Enterobacteriaceae in the 2 months after administration. Fecal antibiotic resistance gene carriage decreased in direct relationship to the degree to which donor microbiota engrafted.

CONCLUSIONS

Microbiota-based therapeutics reduce resistance gene abundance and resistant organisms in the recipient gut microbiome. This approach could potentially reduce the risk of infections caused by resistant organisms within the patient and the transfer of resistance genes or pathogens to others.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01925417 ; registered on August 19, 2013.

Factors Associated With Short-Term Eradication of Rectal Colonization by KPC-2 Producing Klebsiella pneumoniae in an Outbreak Setting

Background: KPC-producing Klebsiella pneumoniae (KPCKP) is a threat for patients admitted to healthcare institutions.

Objectives: To assess the efficacy of several decolonization strategies for KPCKP rectal carriage.

Methods: Observational study performed in a 750-bed university center from July to October 2018 on the efficacy of a 10-day non-absorbable oral antibiotic (NAA) regimen (colistin 10 mg/ml, amikacin 8 mg/ml, and nystatin 30 mg/ml, 10 ml/6 h) vs. the same regimen followed by a probiotic (Vivomixx®) for 20 days in adult patients with KPCKP rectal colonization acquired during an outbreak.

Results: Seventy-three patients colonized by KPCKP were included, of which 21 (29%) did not receive any treatment and 52 (71.2%) received NAA either alone (n = 26, 35.6%) or followed by a probiotic (n = 26, 35.6%). Eradication was observed in 56 (76.7%) patients and the only variable significantly associated with it was not receiving systemic antibiotics after diagnosis of rectal carriage [22/24 (91.6%) vs. 34/49 (69.3%), p = 0.04]. Eradication in patients receiving NAA plus probiotic was numerically but not significantly higher than that of controls [23/26 (88.4%) vs. 15/21 (71.4%), p = 0.14] and of those receiving only NAA (OR = 3.4, 95% CI = 0.78–14.7, p = 0.09).

Conclusion: In an outbreak setting, rectal carriage of KPCKP persisted after a mean of 36 days in about one quarter of patients. The only factor associated with eradication was not receiving systemic antibiotic after diagnosis. A 10-day course of NAA had no impact on eradication. Probiotics after NAA may increase the decolonization rate, hence deserving further study.

Optimal Design of Paired Built Environment Interventions for Control of MDROs in Acute Care and Community Hospitals

OBJECTIVES

Our goal was to optimize infection control of paired environmental control interventions within hospitals to reduce methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacteriaceae (CRE), and vancomycin-resistant Enterococci (VRE).

BACKGROUND

The most widely used infection control interventions are deployment of handwashing (HW) stations, control of relative humidity (RH), and negative pressure (NP) treatment rooms. Direct costs of multidrug-resistant organism (MDRO) infections are typically not included in the design of such interventions.

METHODS

We examined the effectiveness of pairing HW with RH and HW with NP. We used the following three data sets: A meta-analysis of progression rates from uncolonized to colonized to infected, 6 years of MDRO treatment costs from 400 hospitals, and 8 years of MDRO incidence rates at nine army hospitals. We used these data as inputs into an Infection De-Escalation Model with varying budgets to obtain optimal intervention designs. We then computed the infection and prevention rates and cost savings resulting from these designs.

RESULTS

The average direct cost of an MDRO infection was $3,289, $1,535, and $1,067 for MRSA, CRE, and VRE. The mean annual incidence rates per facility were 0.39%, 0.034%, and 0.011% for MRSA, CRE, and VRE. After applying the cost-minimizing intervention pair to each scenario, the percentage reductions in infections (and annual direct cost savings) in large, community, and small acute care hospitals were 69% ($1.5 million), 73% ($631K), 60% ($118K) for MRSA, 52% ($460.5K), 58% ($203K), 50% ($37K) for CRE, and 0%, 0%, and 50% ($12.8K) for VRE.

CONCLUSION

The application of this Infection De-Escalation Model can guide cost-effective decision making in hospital built environment design to improve control of MDRO infections.

The Effect of Iodine-Containing Nano-Micelles, FS-1, on Antibiotic Resistance, Gene Expression and Epigenetic Modifications in the Genome of Multidrug Resistant MRSA Strain Staphylococcus aureus ATCC BAA-39

Application of supplementary drugs which increase susceptibility of pathogenic bacteria to antibiotics is a promising yet unexplored approach to overcome the global problem of multidrug-resistant infections. The discovery of a new drug, an iodine-containing nano-molecular complex FS-1, which has proven to improve susceptibility to antibiotics in various pathogens, including MRSA strain Staphylococcus aureus ATCC BAA-39TM, allowed studying this phenomenon. Chromosomal DNA and total RNA samples extracted from the FS-1 treated strain (FS) and from the negative control (NC) cultures were sequenced by PacBio SMRT and Ion Torrent technologies, respectively. PacBio DNA reads were used to assemble chromosomal DNA of the NC and FS variants of S. aureus BAA-39 and to perform profiling of epigenetically modified nucleotides. Results of transcriptional profiling, variant calling and detection of epigenetic modifications in the FS variant were compared to the NC variant. Additionally, the genetic alterations caused by the treatment of S. aureus BAA-39 with FS-1 were compared to the results of a similar experiment conducted with another model organism, E. coli ATCC BAA-196. Several commonalities in responses of these phylogenetically distant microorganisms to the treatment with FS-1 were discovered, which included metabolic transition toward anaerobiosis and oxidative/osmotic stress response. S. aureus culture appeared to be more sensitive to FS-1 due to a higher penetrability of cells by iodine bound compounds, which caused carbonyl stress associated with nucleotide damaging by FS-1, abnormal epigenetic modifications and an increased rate of mutations. It was hypothesized that the disrupted pattern of adenine methylated loci within methicillin-resistance chromosome cassettes (SCCmec) may promote excision of this antibiotic resistance determinant from chromosomes while the altered pattern of cytosine methylation was behind the adaptive gene regulation in the culture FS. The selection against the antibiotic resistance in bacterial populations caused by abnormal epigenetic modifications exemplifies possible mechanisms of antibiotic resistance reversion induced by iodine-containing compounds. These finding will facilitate development of therapeutic agents against multidrug-resistant infections.

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.

Bacterial, Gut Microbiome-Modifying Therapies to Defend against Multidrug Resistant Organisms

Antibiotics have revolutionized human and animal healthcare, but their utility is reduced as bacteria evolve resistance mechanisms over time. Thankfully, there are novel antibiotics in the pipeline to overcome resistance, which are mentioned elsewhere in this special issue, but eventually bacteria are expected to evolve resistance to most new compounds as well. Multidrug resistant organisms (MDROs) that cause infections increase morbidity, mortality, and readmissions as compared with susceptible organisms. Consequently, many research and development pipelines are focused on non-antibiotic strategies, including fecal microbiota transplantation (FMT), probiotics and prebiotics, and a range of therapies in between. Studies reviewed here focus on efforts to directly treat or prevent MDRO infections or colonization. The studies were collected through clinicaltrials.gov, PubMed, and the International Conference on the Harmonisation Good Clinical Practice website (ichgcp.net). While the gold standard of clinical research is randomized controlled trials (RCTs), several pilot studies are included because the field is so young. Although a vast preclinical body of research has led to studies in humans, animal and in vitro studies are not within the scope of this review. This narrative review discusses microbiome-modifying therapies targeting MDROs in the gut and includes current results, ongoing clinical trials, companies with therapies in the pipeline specifically for MDROs, and commentary on clinical implementation and challenges.

A Rare Opportunist, Morganella morganii, Decreases Severity of Polymicrobial Catheter-Associated Urinary Tract Infection

Catheter-associated urinary tract infections (CAUTIs) are common hospital-acquired infections and frequently polymicrobial, which complicates effective treatment. However, few studies experimentally address the consequences of polymicrobial interactions within the urinary tract, and the clinical significance of polymicrobial bacteriuria is not fully understood. Proteus mirabilis is one of the most common causes of monomicrobial and polymicrobial CAUTI and frequently cocolonizes with Enterococcus faecalis, Escherichia coli, Providencia stuartii, and Morganella morganiiP. mirabilis infections are particularly challenging due to its potent urease enzyme, which facilitates formation of struvite crystals, catheter encrustation, blockage, and formation of urinary stones. We previously determined that interactions between P. mirabilis and other uropathogens can enhance P. mirabilis urease activity, resulting in greater disease severity during experimental polymicrobial infection. Our present work reveals that M. morganii acts on P. mirabilis in a contact-independent manner to decrease urease activity. Furthermore, M. morganii actively prevents urease enhancement by E. faecalis, P. stuartii, and E. coli Importantly, these interactions translate to modulation of disease severity during experimental CAUTI, predominantly through a urease-dependent mechanism. Thus, products secreted by multiple bacterial species in the milieu of the catheterized urinary tract can directly impact prognosis.

Biochar accelerates the removal of tetracyclines and their intermediates by altering soil properties

Tetracyclines accumulation in soil environment potentially threatens agroecosystem safety. Interestingly, biochar could clean up organic pollutants, but to what extent biochar affects the removal of tetracyclines is unknown. To investigate it, five types of biochars derived from cow manure (CMB) and other four plant materials were respectively added into soils contaminated with a mixture of tetracycline, oxytetracycline, and chlortetracycline for 60-day incubation in the dark. Three parent tetracyclines and their corresponding intermediates (epitetracycline, anhydrotetracycline, epianhydrotetracycline, epioxytetracycline, epichlortetracycline, and demethylchlortetracycline) were respectively determined and named as TTCs, OTCs and CTCs. Obtained results showed biochar especially CMB could effectively remove the antibiotics (P < 0.05). Compared to control, the removal rate of TTCs, OTCs and CTCs respectively increased by up to 10.86%, 10.29% and 10.12% in CMB-added soil. The increased removal rate of the antibiotics after biochar addition was due to the increasing accessibilities for degrading microorganisms via the elevating electrical conductivity. Moreover, biochar addition might stimulate these microbial activities through the increase of C and N supplement. Our results indicate biochar accelerates the removal of tetracyclines and their intermediates by altering soil properties and thus increasing the antibiotics accessibilities, which provide insights into how biochar accelerates the removal for these antibiotics.

The 2018 Aged Care National Antimicrobial Prescribing Survey: results show room for improvement

The annual Aged Care National Antimicrobial Prescribing Survey aims to identify local and national prescribing issues and guide antimicrobial stewardship goals In the 2018 point prevalence survey, medication charts of over 20,000 residents were reviewed from 407 participating facilities across Australia On the day of the survey, almost 10% of residents were prescribed an antimicrobial Nearly two-thirds of recently prescribed antimicrobials were for residents who had no documented signs or symptoms of infection Over a quarter of antimicrobials had been prescribed for longer than six months Incomplete documentation was a prominent barrier to proper review of antimicrobial therapy, with the indication, review date or stop date not documented for many prescriptions Recommendations include using appropriate microbiological testing to guide prescribing, following national antimicrobial prescribing guidelines, documenting the indication for the antimicrobial, and its start, stop and review dates, and monitoring and re-evaluating long-term antimicrobial use

Colonizing multidrug-resistant bacteria and the longitudinal evolution of the intestinal microbiome after liver transplantation

Infections by multidrug-resistant bacteria (MDRB) remain a leading cause of morbidity and mortality after liver transplantation (LT). Gut dysbiosis characteristic of end-stage liver disease may predispose patients to intestinal MDRB colonization and infection, in turn exacerbating dysbiosis. However, relationships between MDRB colonization and dysbiosis after LT remain unclear. We prospectively recruited 177 adult patients undergoing LT at a single tertiary care center. 16 S V3-V4 rRNA sequencing was performed on 723 fecal samples collected pre-LT and periodically until one-year post-LT to test whether MDRB colonization was associated with decreased microbiome diversity. In multivariate linear mixed-effect models, MDRB colonization predicts reduced Shannon α-diversity, after controlling for underlying liver disease, antibiotic exposures, and clinical complications. Importantly, pre-LT microbial markers predict subsequent colonization by MDRB. Our results suggest MDRB colonization as a major, previously unrecognized, marker of persistent dysbiosis. Therapeutic approaches accounting for microbial and clinical factors are needed to address post-transplant microbiome health.

Nanoarray Digital Polymerase Chain Reaction with High-Resolution Melt for Enabling Broad Bacteria Identification and Pheno-Molecular Antimicrobial Susceptibility Test

Toward combating infectious diseases caused by pathogenic bacteria, there remains an unmet need for diagnostic tools that can broadly identify the causative bacteria and determine their antimicrobial susceptibilities from complex and even polymicrobial samples in a timely manner. To address this need, a microfluidic and machine-learning-based platform that performs broad bacteria identification (ID) and rapid yet reliable antimicrobial susceptibility testing (AST) is developed. Specifically, this platform builds on "pheno-molecular AST", a strategy that transforms nucleic acid amplification tests (NAATs) into phenotypic AST through quantitative detection of bacterial genomic replication, and utilizes digital polymerase chain reaction (PCR) and digital high-resolution melt (HRM) to quantify and identify bacterial DNA molecules. Bacterial species are identified using integrated experiment-machine learning algorithm via HRM profiles. Digital DNA quantification allows for rapid growth measurement that reflects susceptibility profiles of each bacterial species within only 30 min of antibiotic exposure. As a demonstration, multiple bacterial species and their susceptibility profiles in a spiked-in polymicrobial urine specimen were correctly identified with a total turnaround time of ∼4 h. With further development and clinical validation, this platform holds the potential for improving clinical diagnostics and enabling targeted antibiotic treatments.

Discovery of novel oxoindolin derivatives as atypical dual inhibitors for DNA Gyrase and FabH

The antibacterial agents and therapies today are facing serious problems such as drug resistance. Introducing dual inhibiting effect is a valid approach to solve this trouble and bring advantages including wide adaptability, favorable safety and superiority of combination. We started from potential DNA Gyrase inhibitory backbone isatin to develop oxoindolin derivatives as atypical dual Gyrase (major) and FabH (assistant) inhibitors via a two-round screening. Aiming at blocking both duplication (Gyrase) and survival (FabH), most of synthesized compounds indicated potency against Gyrase and some of them inferred favorable inhibitory effect on FabH. The top hit I18 suggested comparable Gyrase inhibitory activity (IC₅₀ = 0.025 μM) and antibacterial effect with the positive control Novobiocin (IC₅₀ = 0.040 μM). FabH inhibitory activity (IC₅₀ = 5.20 μM) was also successfully introduced. Docking simulation hinted possible important interacted residues and binding patterns for both target proteins. Adequate Structure-Activity Relation discussions provide the future orientations of modification. With high potency, low initial toxicity and dual inhibiting strategy, advanced compounds with therapeutic methods will be developed for clinical application.

Prior antibiotic use and acquisition of multidrug-resistant organisms in hospitalized children: A systematic review

Objective:

Multidrug-resistant organisms (MDROs) cause ~5%–10% of infections in hospitalized children, leading to an increased risk of death, prolonged hospitalization, and additional costs. Antibiotic exposure is considered a driving factor of MDRO acquisition; however, consensus regarding the impact of antibiotic factors, especially in children, is lacking. We conducted a systematic review to examine the relationship between antibiotic use and subsequent healthcare-associated infection or colonization with an MDRO in children.

Design:

Systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline.

Methods:

We searched PubMed and Embase for all English, peer-reviewed original research studies published before September 2018. Included studies evaluated hospitalized children, antibiotic use as an exposure, and bacterial MDRO as an outcome.

Results:

Of the 535 studies initially identified, 29 met the inclusion criteria. Overall, a positive association was identified in most studies evaluating a specific antibiotic exposure (17 of 21, 81%), duration of antibiotics (9 of 12, 75%), and number of antibiotics received (2 of 3, 67%). Those studies that evaluated any antibiotic exposure had mixed results (5 of 10, 50%). Study sites, populations, and definitions of antibiotic use and MDROs varied widely.

Conclusions:

Published studies evaluating this relationship are limited and are of mixed quality. Limitations include observation bias in recall of antibiotic exposure, variations in case definitions, and lack of evaluation of antibiotic dosing and appropriateness. Additional studies exploring the impact of antibiotic use and MDRO acquisition may be needed to develop effective antibiotic stewardship programs for hospitalized children.

Hybrid Ofloxacin/eugenol co-loaded solid lipid nanoparticles with enhanced and targetable antimicrobial properties

In the global context of an imminent emergence of multidrug-resistant microorganisms, the present work combined the use of nanotechnology and the therapeutic benefits of natural compounds as a strategy to potentiate antimicrobial action of the wide-spectrum antibiotic Ofloxacin (Ofx). Hybrid solid lipid nanoparticles (SLN) were synthesized by incorporation of chitosan (Chi, a cationic biopolymer with antimicrobial activity) and eugenol (Eu, a phenolic compound that interferes with bacterial quorum sensing) into a lipid matrix by hot homogenization/ultrasonication method. The developed SLN/Chi/Eu sustainably released the encapsulated Ofx for 24 h. Characterization by DLS, TEM, DSC, TGA and XRD revealed the presence of positively charged spherical nanoparticles with diameters around 300 nm and Ofx entrapped in amorphous state. The SLN exhibited an enhanced bactericidal activity against Pseudomonas aeruginosa and Staphylococcus aureus. The minimum inhibitory concentration (MIC) for free and nanoencapsulated Ofx formulations was below 1.0 µg/ml. The MIC values decreased by 6.1- to 16.1-fold when Ofx was encapsulated in SLN/Chi/Eu. Fluorescent-labeled nanoparticles had the ability to interact with the bacterial cell membrane. Selective toxicity of SLN/Chi/Eu-Ofx was tested in the range of 0.3-30.0 µg/ml and showed no toxicity up to 3.0 µg/ml Ofx in human cell models (A549 and Wi-38) at 24 h and 48 h exposure. It was proved that the administration of hybrid SLN to mice by dry powder inhalation reached therapeutic Ofx levels in lungs.

Borrelia and Chlamydia Can Form Mixed Biofilms in Infected Human Skin Tissues

Our research group has recently shown that Borrelia burgdorferi, the Lyme disease bacterium, is capable of forming biofilms in Borrelia-infected human skin lesions called Borrelia lymphocytoma (BL). Biofilm structures often contain multiple organisms in a symbiotic relationship, with the goal of providing shelter from environmental stressors such as antimicrobial agents. Because multiple co-infections are common in Lyme disease, the main questions of this study were whether BL tissues contained other pathogenic species and/or whether there is any co-existence with Borrelia biofilms. Recent reports suggested Chlamydia-like organisms in ticks and Borrelia-infected human skin tissues; therefore, Chlamydia-specific polymerase chain reaction (PCR) analyses were performed in Borrelia-positive BL tissues. Analyses of the sequence of the positive PCR bands revealed that Chlamydia spp. DNAs are indeed present in these tissues, and their sequences have the best identity match to Chlamydophila pneumoniae and Chlamydia trachomatis. Fluorescent immunohistochemical and in situ hybridization methods demonstrated the presence of Chlamydia antigen and DNA in 84% of Borrelia biofilms. Confocal microscopy revealed that Chlamydia locates in the center of Borrelia biofilms, and together, they form a well-organized mixed pathogenic structure. In summary, our study is the first to show Borrelia-Chlamydia mixed biofilms in infected human skin tissues, which raises the questions of whether these human pathogens have developed a symbiotic relationship for their mutual survival.

Role of place of acquisition and inappropriate empirical antibiotic therapy on the outcome of extended-spectrum β-lactamase-producing Enterobacteriaceae infections

The impact of inappropriate empirical antibiotic therapy (IEAT) on the outcome of severe infections due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-Ent) remains unclear. Current evidence is limited by study design and lack of confounder control. The main objective of this study was to define the outcome of severe infections due to ESBL-Ent according to clinical parameters and place of infection acquisition. Adult hospitalised patients with ESBL-Ent infections were included in a 3-year multicentre prospective study. Primary outcomes were IEAT rates and crude mortality of severe infections, adjusted by place of acquisition [community-acquired infection (CAI), healthcare-associated infection (HCAI) and hospital-acquired infection (HAI)]. Among 729 patients, 519 (71.2%) were diagnosed with HAI, 176 (24.1%) with HCAI and 34 (4.7%) with CAI. Moreover, 32.9% of patients received IEAT; higher rates of IEAT were observed in pneumonia (23%) and deep surgical site infections (19%). HCAIs were more frequently associated with IEAT than HAIs (48.3% vs. 27.9%; OR = 1.7, 95% CI 1.2-2.4). The overall mortality rate for severe infections (n = 264) was 12.1% and was significantly higher in HCAIs (20%) than HAIs (10%) (RR = 2.3, 95% CI 1.01-5.3). IEAT significantly increased the risk of mortality in bloodstream infections (RR = 8.3, 95% CI 2-46.3). Rates of IEAT and overall mortality of ESBL-Ent severe infections were higher in HCAIs than HAIs. Prompt diagnosis of patients with severe HCAIs due to ESBL-Ent is essential since these infections receive high rates of IEAT and significantly higher mortality than HAIs [ClinicalTrials.gov Identifier: NCT00404625].

Evaluating Efficacy of Antimicrobial and Antifouling Materials for Urinary Tract Medical Devices: Challenges and Recommendations

In Europe, the mean incidence of urinary tract infections in intensive care units is 1.1 per 1000 patient-days. Of these cases, catheter-associated urinary tract infections (CAUTI) account for 98%. In total, CAUTI in hospitals is estimated to give additional health-care costs of £1-2.5 billion in the United Kingdom alone. This is in sharp contrast to the low cost of urinary catheters and emphasizes the need for innovative products that reduce the incidence rate of CAUTI. Ureteral stents and other urinary-tract devices suffer similar problems. Antimicrobial strategies are being developed, however, the evaluation of their efficacy is very challenging. This review aims to provide considerations and recommendations covering all relevant aspects of antimicrobial material testing, including surface characterization, biocompatibility, cytotoxicity, in vitro and in vivo tests, microbial strain selection, and hydrodynamic conditions, all in the perspective of complying to the complex pathology of device-associated urinary tract infection. The recommendations should be on the basis of standard assays to be developed which would enable comparisons of results obtained in different research labs both in industry and in academia, as well as provide industry and academia with tools to assess the antimicrobial properties for urinary tract devices in a reliable way.

Vancomycin use in surrounding patients during critical illness and risk for persistent colonization with vancomycin-resistant Enterococcus

The optimal duration of contact precautions for vancomycin-resistant enterococcus (VRE)-colonized patients is uncertain and individual patient characteristics alone may not predict risk of prolonged colonization. Using a cohort of adult patients who underwent testing for VRE at intensive care unit (ICU) admission, we tested the association between local (unit-level) vancomycin use and persistent colonization with VRE. Higher unit-level vancomycin use significantly prolonged VRE colonization (P=0.03) independent of patient-level vancomycin use and unit VRE density.

Urinary Catheter-Associated Infections

Catheter-associated urinary tract infection remains one of the most prevalent, yet preventable, health care-associated infections. General prevention strategies include strict adherence to hand hygiene and antimicrobial stewardship. Duration of urinary catheterization is the most important modifiable risk factor. Targeted prevention strategies include limiting urinary catheter use; physician reminder systems, nurse-initiated discontinuation protocols, and automatic stop orders have successfully decreased catheter duration. Alternatives should be considered. If catheterization is necessary, proper aseptic practices for insertion and maintenance and closed catheter collection systems are essential for prevention. The use of bladder bundles and collaboratives aids in the effective implementation of prevention measures.

Stewarding antibiotic stewardship in intensive care units with Bayesian artificial intelligence

Emerging antimicrobial resistance (AMR) is a global threat to life. Injudicious use of antibiotics is the biggest driver of resistance evolution, creating selection pressures on micro-organisms. Intensive care units (ICUs) are the strongest contributors to this pressure, owing to high infection and antibiotic usage rates. Antimicrobial stewardship programs aim to control antibiotic use; however, these are mostly limited to descriptive statistics. Genomic analyses lie at the other extreme of the value-spectrum, and together these factors predispose to siloing of knowledge arising from AMR stewardship. In this study, we bridged the value-gap at a Pediatric ICU by creating Bayesian network (BN) artificial intelligence models with potential impacts on antibiotic stewardship. Methods, actionable insights and an interactive dashboard for BN analysis upon data observed over 3 years at the PICU are described. BNs have several desirable properties for reasoning from data, including interpretability, expert knowledge injection and quantitative inference. Our pipeline leverages best practices of enforcing statistical rigor through bootstrapping, ensemble averaging and Monte Carlo simulations. Competing, shared and independent drug resistances were discovered through the presence of network motifs in BNs. Inferences guided by these visual models are also discussed, such as increasing the sensitivity testing for chloramphenicol as a potential mechanism of avoiding ertapenem overuse in the PICU. Organism, tissue and temporal influences on drug co-resistances are also discussed. While the model represents inferences that are tailored to the site, BNs are excellent tools for building upon pre-learnt structures, hence the model and inferences were wrapped into an interactive dashboard not only deployed at the site, but also made openly available to the community via GitHub. Shared repositories of such models could be a viable alternative to raw-data sharing and could promote partnering, learning across sites and charting a joint course for antimicrobial stewardship programs in the race against AMR.