Accuracy of Xpert Carba-R Assay for the Diagnosis of Carbapenemase-producing Organisms from Rectal Swabs in Asia: a Diagnostic Meta-analysis

The Cepheid Xpert Carba-R assay has been demonstrated to be reliable for rapid detection of carbapenemase-producing orgnisms (CPO) directly from rectal swabs but the performance of which remains unclear in Asia.We searched PubMed, EMBASE and Cochrane Library databases to identify studies according to predetermined criteria. STATA 13.0 software was used to analyze the tests for sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), area under the summary receiver operating characteristic curves (AUC). QUADAS-2 was used to assess the quality of included studies with RevMan 5.2. A total of 5 unique studies involving 10807 samples met the inclusion criteria. The pooled sensitivity, specificity, PLR, NLR, and the AUC with 95% CIs of Xpert Carba-R were 0.91 (0.72-0.97), 0.99 (0.96-1.00), 71.24 (25.41-199.73), 0.09 (0.03-0.32), 0.99 (0.98-1.00), respectively. Deeks'funnel plot showed no publication bias.The present meta-analysis showed the Xpert Carba-R assay had good sensitivity and perfect specificity for detecting CPOs on rectal swabs.

Genetic and structural basis of colistin resistance in Klebsiella pneumoniae: Unravelling the molecular mechanisms

OBJECTIVE

Antimicrobial resistance (AMR), together with multidrug resistance (MDR), mainly among Gram-negative bacteria, has been on the rise. Colistin (polymyxin E) remains one of the primary available last resorts to treat infections caused by MDR bacteria during the rapid emergence of global resistance. As the exact mechanism of bacterial resistance to colistin remains undetermined, this study warranted elucidation of the underlying mechanisms of colistin resistance and heteroresistance among carbapenem-resistant Klebsiella pneumoniae isolates.

METHODS

Molecular analysis was carried out on the resistant isolates using a genome-wide characterisation approach, as well as MALDI-TOF mass spectrometry, to identify lipid A.

RESULTS

Among the 32 carbapenem-resistant K. pneumoniae isolates, several isolates showed resistance and intermediate resistance to colistin. The seven isolates with intermediate resistance exhibited the "skip-well" phenomenon, attributed to the presence of resistant subpopulations. The three isolates with full resistance to colistin showed ions using MALDI-TOF mass spectrometry at m/z of 1840 and 1824 representing bisphosphorylated and hexa-acylated lipid A, respectively, with or without hydroxylation at position C'-2 of the fatty acyl chain. Studying the genetic environment of mgrB locus revealed the presence of two insertion sequences that disrupted the mgrB locus in the three colistin-resistant isolates: IS1R and IS903B.

CONCLUSIONS

Our findings show that colistin resistance/heteroresistance was inducible with mutations in chromosomal regulatory networks controlling the lipid A moiety and insertion sequences disrupting the mgrB gene, leading to elevated minimum inhibitory concentration values and treatment failure. Different treatment strategies should be employed to avoid colistin heteroresistance-linked treatment failures, mainly through combination therapy using colistin with carbapenems, aminoglycosides, or tigecycline.

External quality assessment schemes in bacteriology support public health in Germany-results from 2006 to 2023

External Quality Assessment schemes (EQAS) are mandatory to ensure quality standards in diagnostic methods and achieve laboratory accreditation. As host institution for two German culture-based bacteriology EQAS (RV-A and RV-B), we investigated the obtained data of 590 up to 720 surveys per year in RV-A and 2,151 up to 2,929 in RV-B from 2006 to 2023. As educational instruments, they function to review applied methodology and are valuable to check for systemic- or method-dependent failures in microbiology diagnostics or guidelines. Especially, containment of multi-resistant bacteria in times of rising antibiotic resistance is one major point to assure public health. The correct identification and reporting of these strains is therefore of high importance to achieve this goal. Moreover, correct antimicrobial susceptibility testing (AST) per se is important for selecting appropriate therapy, to restrict broad-spectrum antibiotics and minimize resistance development. The reports of participating laboratories displayed a high level of correct identification results in both schemes with mostly consistent failure rates around 2.2% (RV-A) and 3.9% (RV-B) on average. In contrast, results in AST revealed increasing failure rates upon modification of AST requirements concerning adherence to standards and subsequent bacterial species-specific evaluation. Stratification on these periods revealed in RV-A a moderate increase from 1.3% to 4.5%, while in RV-B failure rates reached 14% coming from 4.3% on average. Although not mandatory, subsequent AST evaluation and consistent reporting are areas of improvement to benefit public health.

Genomic Characterization of Carbapenemase-Producing Enterobacter hormaechei, Serratia marcescens, Citrobacter freundii, Providencia stuartii, and Morganella morganii Clinical Isolates from Bulgaria

Carbapenemase-producing Enterobacter spp. Serratia marcescens, Citrobacter freundii, Providencia spp., and Morganella morganii (CP-ESCPM) are increasingly identified as causative agents of nosocomial infections but are still not under systematic genomic surveillance. In this study, using a combination of whole-genome sequencing and conjugation experiments, we sought to elucidate the genomic characteristics and transferability of resistance genes in clinical CP-ESCPM isolates from Bulgaria. Among the 36 sequenced isolates, NDM-1 (12/36), VIM-4 (11/36), VIM-86 (8/36), and OXA-48 (7/36) carbapenemases were identified; two isolates carried both NDM-1 and VIM-86. The majority of carbapenemase genes were found on self-conjugative plasmids. IncL plasmids were responsible for the spread of OXA-48 among E. hormaechei, C. freundii, and S. marcescens. IncM2 plasmids were generally associated with the spread of NDM-1 in C. freundii and S. marcescens, and also of VIM-4 in C. freundii. IncC plasmids were involved in the spread of the recently described VIM-86 in P. stuartii isolates. IncC plasmids carrying blaNDM-1 and blaVIM-86 were observed too. blaNDM-1 was also detected on IncX3 in S. marcescens and on IncT plasmid in M. morganii. The significant resistance transfer rates we observed highlight the role of the ESCPM group as a reservoir of resistance determinants and stress the need for strengthening infection control measures.

Risk Factors and Outcomes of Patients Colonized with KPC and NDM Carbapenemase-Producing Enterobacterales

Carbapenemase-producing enterobacterales (CPE) poses an increasing threat in hospitals worldwide. Recently, the prevalence of different carbapenemases conferring carbapenem resistance in enterobacterales changed in our country, including an increase in New Delhi Metallo-beta-lactamase (NDM)-CPE. We conducted a comparative historical study of adult patients colonized with Klebsiella pneumoniae carbapenemase (KPC)-CPE (July 2016 to June 2018, a historical cohort) vs. NDM-CPE (July 2016 to January 2023). We identified patients retrospectively through the microbiology laboratory and reviewed their files, extracting demographics, underlying diseases, Charlson Comorbidity Index (CCI) scores, treatments, and outcomes. This study included 228 consecutive patients from whom a CPE rectal swab screening was obtained: 136 NDM-CPE positive and 92 KPC-CPE positive. NDM-CPE-colonized patients had a shorter hospitalization length and a significantly lower 30-day post-discharge mortality rate (p = 0.002) than KPC-CPE-colonized patients. Based on multivariate regression, independent risk factors predicting CPE-NDM colonization included admission from home and CCI < 4 (p < 0.001, p = 0.037, respectively). The increase in NDM-CPE prevalence necessitates a modified CPE screening strategy upon hospital admission tailored to the changing local CPE epidemiology. In our region, the screening of younger patients residing at home with fewer comorbidities should be considered, regardless of a prior community healthcare contact or hospital admission.

National genomic epidemiology investigation revealed the spread of carbapenem-resistant Escherichia coli in healthy populations and the impact on public health

BACKGROUND

Carbapenem-resistant Escherichia coli (CREC) has been considered as WHO priority pathogens, causing a great public health concern globally. While CREC from patients has been thoroughly investigated, the prevalence and underlying risks of CREC in healthy populations have been overlooked. Systematic research on the prevalence of CREC in healthy individuals was conducted here. We aimed to characterize CREC collected from healthy populations in China between 2020 and 2022 and to compare the genomes of CREC isolates isolated from healthy individuals and clinical patients.

METHODS

We present a nationwide investigation of CREC isolates among healthy populations in China, employing robust molecular and genomic analyses. Antimicrobial susceptibility testing, whole-genome sequencing, and bioinformatics were utilized to analyze a cohort of CREC isolates (n = 113) obtained from fecal samples of 5 064 healthy individuals. Representative plasmids were extracted for third-generation nanopore sequencing. We previously collected 113 non-duplicate CREC isolates (59 in 2018, 54 in 2020) collected from ICU patients in 15 provinces and municipalities in China, and these clinical isolates were used to compare with the isolates in this study. Furthermore, we employ comparative genomics approaches to elucidate molecular variations and potential correlations between clinical and non-clinical CREC isolates.

RESULTS

A total of 147 CREC isolates were identified from 5 064 samples collected across 11 provinces in China. These isolates were classified into 64 known sequence types (STs), but no dominant STs were observed. In total, seven carbapenemase genes were detected with blaNDM-5 (n = 116) being the most prevalent one. Genetic environments and plasmid backbones of blaNDM were conserved in CREC isolated from healthy individuals. Furthermore, we compared clinical and healthy human-originated CRECs, revealing noteworthy distinctions in 23 resistance genes, including blaNDM-1, blaNDM-5, and blaKPC (χ2 test, p < 0.05). Clinical isolates contained more virulence factors associated with iron uptake, adhesion, and invasion than those obtained from healthy individuals. Notably, CREC isolates generally found healthy people are detected in hospitalized patients.

CONCLUSIONS

Our findings underscore the significance of healthy populations-derived CRECs as a crucial reservoir of antibiotic resistance genes (ARGs). This highlights the need for ongoing monitoring of CREC isolates in healthy populations to accurately assess the potential risks posed by clinical CREC isolates.

Country-wide expansion of a VIM-1 carbapenemase-producing Klebsiella oxytoca ST145 lineage in Poland, 2009-2019

PURPOSE

To elucidate the role of the Klebsiella oxytoca species complex (KoSC) in epidemiology of VIM-type MBL-producing Enterobacterales in Poland.

METHODS

The study comprised all 106 VIM-positive KoSC isolates collected by the Polish National Reference Centre for Susceptibility Testing during 2009-2019 from 60 institutions in 35 towns. All isolates were sequenced by Illumina MiSeq, followed by MinION sequencing of selected organisms. Genomes were subjected to bioinformatic analysis, addressing taxonomy, clonality, phylogeny and structural characterisation of key resistance determinants within their chromosomal and plasmidic loci.

RESULTS

Among five species identified, K. oxytoca was predominant (n = 92), followed by Klebsiella michiganensis (n = 11). MLST distinguished 18 STs, with the most prevalent Klebsiella oxytoca ST145 (n = 83). The clone segregated a lineage with the In237-like integron [blaVIM-1-aacA4 genes; n = 78], recorded in 28 cities almost all over the country. The integron was located in a ~ 49-50 kb chromosomal mosaic region with multiple other resistance genes, linked to a ~ 51 kb phage-like element. The organism might have originated from Greece, and its evolution in Poland included several events of chromosomal ~ 54-258 kb deletions, comprising the natural β-lactamase blaOXY gene. A group of other isolates of various species and clones (n = 12) carried the integron In916 on self-transmissible IncA-type plasmids, effectively spreading in Italy, France and Poland.

CONCLUSION

KoSC has been one of the major VIM producers in Poland, owing largely to clonal expansion of the specific K. oxytoca-In237-like lineage. Its apparently enhanced epidemic potential may create a danger on international scale.

Factors Associated with Extended-Spectrum β-Lactamases and Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections: A Five-Year Retrospective Study

Klebsiella pneumoniae is one of the leading causes of nosocomial infections. It has been estimated that nosocomial infection by Klebsiella pneumoniae comprises 3-8% of all nosocomial infections. Klebsiella pneumoniae bloodstream infections (BSIs) occur worldwide with varying mortality. Resistant strains, like those producing extended-spectrum beta-lactamases (ESBL) and carbapenemases, are becoming increasingly common, especially in hospital settings, posing therapeutic challenges. In this article, we aimed to study the epidemiology and risk factors of BSIs due to resistant Klebsiella pneumoniae strains in the period 1 January 2014-31 December 2018 at the Nicosia General Hospital, the largest tertiary hospital in Cyprus. Data on demographics, co-morbidities, prior hospitalization, prior intensive care unit (ICU) admission, previous antimicrobial use, nosocomial acquisition of the infection, the presence of a prosthetic device or surgery, and the primary site of infection were retrospectively recorded. Associations between the detection of ESBL Klebsiella pneumoniae BSIs and factors/covariates were examined using logistic regression. This study involved 175 patients with BSI caused by Klebsiella pneumoniae. Of these, 61 BSIs were caused by ESBL strains, 101 by non-ESBL, and 13 by carbapenem-resistant (CR) strains. In univariable analyses, age, sex, heart disease, antimicrobial use during current admission, previous hospitalization (ward or ICU), and primary BSI were associated with the presence of an ESBL strain. Antibiotic use during current admission and heart disease remained statistically significantly associated with ESBL Klebsiella pneumoniae BSI in multivariable models. Antibiotic use during current admission, respiratory infection, and a recent history of surgery were more prevalent among CR Klebsiella pneumoniae BSI patients than among non-CR Klebsiella pneumoniae BSI patients. Our study showed that recent antimicrobial use and heart disease were associated with BSI due to ESBL-producing Klebsiella pneumoniae. This finding could inform clinical practice in hospital settings.

The CARBA-MAP study: national mapping of carbapenemases in Spain (2014-2018)

Introduction

Infections caused by carbapenem-resistant Enterobacterales (CRE) and carbapenem-resistant Pseudomonas aeruginosa, including isolates producing acquired carbapenemases, constitute a prevalent health problem worldwide. The primary objective of this study was to determine the distribution of the different carbapenemases among carbapenemase-producing Enterobacterales (CPE, specifically Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae complex, and Klebsiella aerogenes) and carbapenemase-producing P. aeruginosa (CPPA) in Spain from January 2014 to December 2018.

Methods

A national, retrospective, cross-sectional multicenter study was performed. The study included the first isolate per patient and year obtained from clinical samples and obtained for diagnosis of infection in hospitalized patients. A structured questionnaire was completed by the participating centers using the REDCap platform, and results were analyzed using IBM SPSS Statistics 29.0.0.

Results

A total of 2,704 carbapenemase-producing microorganisms were included, for which the type of carbapenemase was determined in 2692 cases: 2280 CPE (84.7%) and 412 CPPA (15.3%), most often using molecular methods and immunochromatographic assays. Globally, the most frequent types of carbapenemase in Enterobacterales and P. aeruginosa were OXA-48-like, alone or in combination with other enzymes (1,523 cases, 66.8%) and VIM (365 cases, 88.6%), respectively. Among Enterobacterales, carbapenemase-producing K. pneumoniae was reported in 1821 cases (79.9%), followed by E. cloacae complex in 334 cases (14.6%). In Enterobacterales, KPC is mainly present in the South and South-East regions of Spain and OXA-48-like in the rest of the country. Regarding P. aeruginosa, VIM is widely distributed all over the country. Globally, an increasing percentage of OXA-48-like enzymes was observed from 2014 to 2017. KPC enzymes were more frequent in 2017-2018 compared to 2014-2016.

Discussion

Data from this study help to understand the situation and evolution of the main species of CPE and CPPA in Spain, with practical implications for control and optimal treatment of infections caused by these multi-drug resistant organisms.

Various arrangements of mobile genetic elements among CC147 subpopulations of Klebsiella pneumoniae harboring blaNDM-1: a comparative genomic analysis of carbapenem resistant strains

BACKGROUND

Certain clonal complexes (CCs) of Klebsiella pneumoniae such as CC147 (ST147 and ST392) are major drivers of blaNDM dissemination across the world. ST147 has repeatedly reported from our geographical region, but its population dynamics and evolutionary trajectories need to be further studied.

METHODS

Comparative genomic analysis of 51 carbapenem-nonsusceptible strains as well as three hypervirulent K. pneumoniae (hvKp) recovered during 16-months of surveillance was performed using various bioinformatics tools. We investigated the genetic proximity of our ST147 strains with publicly available corresponding genomes deposited globally and from neighbor countries in our geographic region.

RESULTS

While IncL/M plasmid harboring blaOXA-48 was distributed among divergent clones, blaNDM-1 was circulated by twenty of the 25 CC147 dominant clone and were mostly recovered from the ICU. The NDM-1 core structure was bracketed by a single isoform of mobile genetic elements (MGEs) [ΔISKpn26-NDM-TnAs3-ΔIS3000-Tn5403] and was located on Col440I plasmid in 68.7% of ST392. However, various arrangements of MGEs including MITESen1/MITESen1 composite transposon or combination of MITESen1/ISSen4/IS903B/IS5/ISEhe3 on IncFIb (pB171) were identified in ST147. It seems that ST392 circulated blaNDM-1 in 2018 before being gradually replaced by ST147 from the middle to the end of sample collection in 2019. ST147 strains possessed the highest number of resistance markers and showed high genetic similarity with four public genomes that harbored blaNDM-1 on the same replicon type. Mainly, there was a convergence between clusters and isolated neighboring countries in the minimum-spanning tree. A conserved arrangement of resistance markers/MGEs was linked to methyltransferase armA which was embedded in class 1 integron in 8 isolates of ST147/ST48 high-risk clones.

CONCLUSION

Our findings highlight the dynamic nature of blaNDM-1 transmission among K. pneumoniae in Iran that occurs both clonally and horizontally via various combinations of MGEs. This is the first analysis of Iranian ST147/NDM + clone in the global context.

Similarity Analysis of Klebsiella pneumoniae Producing Carbapenemases Isolated from UTI and Other Infections

Klebsiella pneumoniae is an important opportunistic pathogen responsible for severe infections, mainly urinary tract infections (UTIs) and pneumonia. Hospital epidemic infections caused by multiresistant strains of carbapenemase-producing K. pneumoniae are the most concerning. NDM-producing strains are resistant to a wide range of antibiotics and have become the most significant threat. Determining the natural reservoirs and routes of infections is essential to end hospital outbreaks. Understanding the relatedness of K. pneumoniae strains is essential to determine the range and nature of the infection. The study compared phylogenetic relatedness between multiresistant K. pneumoniae strains isolated from hospitalized patients. Susceptibility to drugs and mechanisms of resistance were confirmed using phenotypic methods. PFGE was used to analyze the relatedness between strains. We analyzed 69 K. pneumoniae strains from various healthcare units. The isolates were mainly identified from urine. Strains were resistant to β-lactam antibiotics with β-lactamase inhibitors, cephalosporins, and quinolones. Their susceptibility to aminoglycosides and carbapenem antibiotics was diverse. Most of the isolated strains produced New Delhi metallo-ß-lactamase (NDM). Although K. pneumoniae strains were classified into several genotype clusters, closely related isolates were confirmed in the same hospital's wards, and in two hospitals in the same province.

Sanitary installations and wastewater plumbing as reservoir for the long-term circulation and transmission of carbapenemase producing Citrobacter freundii clones in a hospital setting

BACKGROUND

Accumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures.

METHODS

Environmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci.

RESULTS

The CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms.

CONCLUSIONS

Our findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.

Social network and genomic analysis of an OXA-48 carbapenemase-producing Enterobacterales hospital ward outbreak in Ireland, 2018-2019

Background

Nosocomial transmission and outbreaks of carbapenemase-producing Enterobacterales (CPE) represent a challenge to healthcare systems. In July 2018, a CPE hospital ward outbreak was declared. Our aim was to investigate transmission patterns, using social network analysis and genomics in a nosocomial CPE outbreak.

Methods

A retrospective descriptive analysis of all patients (cases and contacts) admitted to a ward experiencing a CPE outbreak (2018-2019) was undertaken. A case had a negative CPE admission screen, and subsequent positive test. A contact shared a multi-bed area and/or facility with a case (>4 hours). Social networks, including genomics data and ward locations, were constructed. Network metrics were analysed.

Findings

Forty-five cases and 844 contacts were analysed. The median age of cases was 78 years (IQR 67-83), 58% (n=26) were male and 100% had co-morbidities. The median outbreak ward length-of-stay (LOS) was 17 days (IQR 10-34). OXA-48 CPE was confirmed in all cases and from 26 environmental samples. Social networks identified clusters by time, gender and species/sequence type/plasmid. Network metrics indicated potential superspreading involving a subset of patients with behavioural issues.

Conclusion

Social networks elucidated high resolution transmission patterns involving two related OXA-48 plasmids, multiple species/genotypes and potential super-spreading. Interventions prevented intra-hospital spread. An older patient cohort, extended hospital LOS and frequent intra-ward bed transfers, coupled with suboptimal ward infrastructure, likely prolonged this outbreak. We recommend social network analysis contemporaneously with genomics (on case and environmental samples) for complex nosocomial outbreaks and bespoke care plans for patients with behavioural issues on outbreak wards.

Rapid diagnostics and ceftazidime/avibactam for KPC-producing Klebsiella pneumoniae bloodstream infections: impact on mortality and role of combination therapy

This study was aimed at investigating risk factors for mortality in patients suffering from KPC-producing Klebsiella pneumoniae (KPC-Kp) bloodstream infections (BSIs), evaluating the impact of rapid diagnostics and ceftazidime/avibactam use. This observational retrospective study (January 2017-May 2021) included all patients with a KPC-Kp BSI. Uni-multivariable analyses were carried out to evaluate the effect of clinical variables on both in-hospital death (IHD) and 30-day all-cause mortality, and the role of the combination of ceftazidime/avibactam plus polymyxin. One hundred and ninety-six patients met the study's inclusion criteria. Older age, having undergone renal replacement therapy during the 30 days preceding the KPC-Kp BSI onset, having an INCREMENT-CPE score ≥ 8, and having suffered from a superimposed and/or following KPC-Kp BSI treatment candidemia were found to be the main factors associated with both mortality rates. Among protective factors, the centrality of ceftazidime/avibactam in monotherapy (IHD: OR: 0.34; CI 95%: 0.11-1.00-30-day all-cause mortality: OR: 0.18; CI 95%: 0.04-0.77) or combination (IHD: OR: 0.51; CI 95%: 0.22-1.19-30-day all-cause mortality: OR: 0.62; CI 95%: 0.21-1.84) emerged and became even more evident once the effect of ceftazidime/avibactam plus polymyxin was removed. Rapid diagnostics may be useful to adopt more effective strategies for the treatment of KPC-Kp BSI patients and implement infection control measures, even if not associated with higher patient survival. Ceftazidime/avibactam, even when used alone, represents an important option against KPC-Kp, while combined use with polymyxin might not have altered its efficacy. Patient comorbidities, severity of BSI, and complications such as candidemia were confirmed to have a significant burden on survival.

Ertapenem Supplemented Selective Media as a New Strategy to Distinguish β-Lactam-Resistant Enterobacterales: Application to Clinical and Wastewater Samples

The increase in carbapenem-resistant Enterobacterales (CRE) is mostly driven by the spread of carbapenemase-producing (CP) strains. In New Caledonia, the majority of carbapenemases found are IMP-type carbapenemases that are difficult to detect on routine selective media. In this study, a culture-based method with ertapenem selection is proposed to distinguish non-CRE, non-CP-CRE, and CP-CRE from samples with very high bacterial loads. Firstly, assays were carried out with phenotypically well-characterized β-lactam-resistant Enterobacterales isolates. Then, this approach was applied to clinical and environmental samples. Presumptive CP-CRE isolates were finally identified, and the presence of a carbapenemase was assessed. In a collection of 27 phenotypically well-characterized β-lactam-resistant Enterobacterales, an ertapenem concentration of 0.5 µg·mL^-1 allowed distinguishing CRE from non-CRE. A concentration of 4 µg·mL^-1 allowed distinguishing CP-CRE from non-CP-CRE after nine hours of incubation. These methods allowed isolating 18 CP-CRE from hospital effluents, including the first detection of a KPC in New Caledonia. All these elements show that this cost-effective strategy to distinguish β-lactam-resistant Enterobacterales provides fast and reliable results. This could be applied in the Pacific islands or other resource-limited settings, where limited data are available.

Estimating the Clinical and Economic Impact of Introducing a New Antibacterial into Greek Clinical Practice for the Management of Hospital-Acquired Infections with Limited Treatment Options

INTRODUCTION

Hospital-acquired infections (HAIs) and growing antimicrobial resistance (AMR) represent a significant healthcare burden globally. Especially in Greece, HAIs with limited treatment options (LTO) pose a serious threat due to increased morbidity and mortality. This study aimed to estimate the clinical and economic value of introducing a new antibacterial for HAIs with LTO in Greece.

METHODS

A previously published and validated dynamic model of AMR was adapted to the Greek setting. The model estimated the clinical and economic outcomes of introducing a new antibacterial for the treatment of HAIs with LTO in Greece. The current treatment pathway was compared with introducing a new antibacterial to the treatment sequence. Outcomes were assessed from a third-party payer perspective, over a 10-year transmission period, with quality-adjusted life years (QALYs) and life years (LYs) gained considered over a lifetime horizon.

RESULTS

Over the next 10 years, HAIs with LTO in Greece account for approximately 1.4 million hospital bed days, hospitalisation costs of more than €320 million and a loss of approximately 403,000 LYs (319,000 QALYs). Introduction of the new antibacterial as first-line treatment provided the largest clinical and economic benefit, with savings of up to 93,000 bed days, approximately €21 million in hospitalisation costs and an additional 286,000 LYs (226,000 QALYs) in comparison to the current treatment strategy. The introduction of a new antibacterial was linked to a monetary benefit of €6.8 billion at a willingness to pay threshold of €30,000 over 10 years.

CONCLUSION

This study highlights the considerable clinical and economic benefit of introducing a new antibacterial for HAIs with LTO in Greece. This analysis shows the additional benefit when a new antibacterial is introduced to treatment sequences. These findings can be used to inform decision makers to implement policies to ensure timely access to new antibacterial treatments in Greece.

Molecular Characterization and Epidemiology of Carbapenem-Resistant Enterobacteriaceae Isolated from Pediatric Patients in Guangzhou, Southern China

Background

Carbapenem-resistant Enterobacteriaceae (CRE) are spreading worldwide, posing a serious public health concern. However, the data on CRE strains that cause infections in children in Guangzhou remain limited. Therefore, this study aimed to investigate the epidemiology of CRE, drug resistance, and resistance mechanisms in children in Guangzhou, Southern China.

Methods

In total, 54 nonrepetitive CRE strains were collected in pediatric patients at three centers in Guangzhou, Southern China, from January 2016 to August 2018. CRE isolates were used for further studies on antimicrobial susceptibility, the modified Hodge test (MHT), the modified carbapenem inactivation method (mCIM), and drug resistance genes. Multilocus sequence typing (MLST) was used to elucidate the molecular epidemiology of K. pneumoniae.

Results

The isolated CRE strains include 34 K. pneumoniae (63.0%), 10 E. coli (18.5%), 4 Enterobacter cloacae (7.4%), and 6 Proteus mirabilis (11.1%) strains. The strains were isolated mainly from the blood (31.5%, n = 17), sputum (31.5%, n = 17), and urine (16.7%, n = 9). All CRE isolates were highly resistant to the third- or fourth-generation cephalosporins, carbapenems, and β-lactam + β-lactamase inhibitors (94.4%-96.3%). In addition, the resistance rates to amikacin, ciprofloxacin, levofloxacin, tigecycline, and colistin were 5.6%, 14.8%, 16.7%, 9.3%, and 0%, respectively. Carbapenemase was detected in 35 (64.8%) of the CRE isolates. The most dominant carbapenemase gene was bla _NDM (n = 17, 48.6%), followed by bla _IMP (n = 13, 37.1%) and bla _OXA-23 (n = 4, 11.4%). Other carbapenemase genes (bla _KPC, bla _sim, bla _Aim, bla _GES, bla _Gim, bla _OXA-2 , and bla _OXA-48 ) and the mcr-1 gene were not detected. MLST analysis showed high diversity among the K. pneumoniae, and ST45 (11.7%, 4/34) was the dominant sequence type.

Conclusion

This study revealed bla _NDM was the most dominant carbapenemase gene in children in Guangzhou. Infection control measures need to be taken for the prevention and treatment of CRE infections.

Limiting the Spread of Multidrug-Resistant Bacteria in Low-to-Middle-Income Countries: One Size Does Not Fit All

The spread of multidrug-resistant organisms (MDRO) is associated with additional costs as well as higher morbidity and mortality rates. Risk factors related to the spread of MDRO can be classified into four categories: bacterial, host-related, organizational, and epidemiological. Faced with the severity of the MDRO predicament and its individual and collective consequences, many scientific societies have developed recommendations to help healthcare teams control the spread of MDROs. These international recommendations include a series of control measures based on surveillance cultures and the application of barrier measures, ranging from patients' being isolated in single rooms, to the reinforcement of hand hygiene and implementation of additional contact precautions, to the cohorting of colonized patients in a dedicated unit with or without a dedicated staff. In addition, most policies include the application of an antimicrobial stewardship program. Applying international policies to control the spread of MDROs presents several challenges, particularly in low-to-middle-income countries (LMICs). Through a review of the literature, this work evaluates the real risks of dissemination linked to MDROs and proposes an alternative policy that caters to the means of LMICs. Indeed, sufficient evidence exists to support the theory that high compliance with hand hygiene and antimicrobial stewardship reduces the risk of MDRO transmission. LMICs would therefore be better off adopting such low-cost policies without necessarily having to implement costly isolation protocols or impose additional contact precautions.

In Silico Characterization of blaNDM-Harboring Conjugative Plasmids in Acinetobacter Species

New Delhi metallo-β-lactamase (NDM)-producing clinical strains in Acinetobacter spp. have been recently reported in many countries and have received considerable attention. The vast majority of blaNDM cases occur on conjugative plasmids, which play a vital role in disseminating blaNDM. To characterize the conjugative plasmids bearing blaNDM genes in Acinetobacter spp., we analyzed the variants of blaNDM, conjugative transfer regions, genetic contexts of blaNDM, and the phylogenetic pattern of the 62 predicted blaNDM-positive plasmids, which were selected from 1,191 plasmids of Acinetobacter species from GenBank. We identified 30 conjugative plasmids from the 62 blaNDM-harboring plasmids in Acinetobacter species, with the oriT sites similar to plasmid pNDM-YR7 in our study, genes coding for relaxases of the MOBQ family, genes encoding type IV coupling proteins (T4CPs) of the TrwB/TraD subfamily, and VirB-like type IV secretion system (T4SS) gene clusters. The genome sizes of all 30 pNDM-YR7-like plasmids ranged from 39.36 kb to 49.65 kb, with a median size of 44.56 kb. The most common species of Acinetobacter containing the blaNDM-positive conjugative plasmids was A. baumannii, followed by Acinetobacter lwoffii and Acinetobacter indicus. Notably, pNDM-YR7 is the first report on a blaNDM-positive conjugative plasmid in Acinetobacter junii. Moreover, all 30 blaNDM-positive conjugative plasmids in Acinetobacter species were found to contain genetic contexts with the structure ISAba14-aph(3')-VI-ISAba125-blaNDM-ble. Our findings provide important insights into the phylogeny and evolution of blaNDM-positive plasmids of Acinetobacter species and further address their role in acquiring and spreading blaNDM genes in Acinetobacter species. IMPORTANCE Conjugative plasmids harboring the blaNDM gene play a vital role in disseminating carbapenem resistance. In this study, we first report a conjugative plasmid, pNDM-YR7, in Acinetobacter junii. Based on the genomic characteristics of the blaNDM-positive pNDM-YR7, we performed in silico typing and comparative analysis of blaNDM-positive plasmids using the 1,191 plasmids of Acinetobacter species available in the NCBI RefSeq database. We analyzed the characteristics of blaNDM-positive plasmids, including the variants of blaNDM, genetic features associated with blaNDM, conjugative transfer regions, and the phylogenetic pattern of the blaNDM-positive plasmids. All 30 blaNDM-positive conjugative plasmids were found to contain an ISAba14-aph(3')-VI-ISAba125-blaNDM-ble region. This study provides novel insights into the phylogeny and evolution of blaNDM-harboring conjugative plasmids and contributes to the repertoire of knowledge surrounding blaNDM-positive plasmids in the genus Acinetobacter.

Molecular Epidemiology and Antimicrobial Resistance of Outbreaks of Klebsiella pneumoniae Clinical Mastitis in Chinese Dairy Farms

Klebsiella pneumoniae is an opportunistic pathogen that causes serious infections in humans and animals. However, the availability of epidemiological information on clinical mastitis due to K. pneumoniae is limited. To acquire new information regarding K. pneumoniae mastitis, data were mined about K. pneumoniae strains on dairy cattle farms (farms A to H) in 7 Chinese provinces in 2021. Hypermucoviscous strains of K. pneumoniae were obtained by the string test. MICs of antimicrobial agents were determined via the broth microdilution method. Ten antimicrobial resistance genes and virulence genes were identified by PCR. The prevalence of K. pneumoniae was 35.91% (65/181), and 100% of the bacteria were sensitive to enrofloxacin. Nine antimicrobial resistance genes and virulence genes were identified and compared among farms. The hypermucoviscous phenotype was present in 94.44% of isolates from farm B, which may be a function of the rmpA virulence gene. Based on these data, the multidrug-resistant strains SD-14 and HB-21 were chosen and sequenced. Genotypes were assayed for K. pneumoniae isolates from different countries and different hosts using multilocus sequence typing (MLST). Ninety-four sequence types (STs) were found, and 6 STs present a risk for spreading in specific regions. Interestingly, ST43 was observed in bovine isolates for the first time. Our study partially reveals the current distribution characteristics of bovine K. pneumoniae in China and may provide a theoretical basis for the prevention and treatment of bovine K. pneumoniae mastitis. IMPORTANCE K. pneumonia is ubiquitous in nature and infects a wide range of hosts, including animals, and humans. It is one of the leading inducements of clinical mastitis (CM) in dairy cows, a prevalent and costly disease that is predominantly associated with bacterial infection. In general, CM caused by Gram-negative bacteria is more difficult to cure than that associated with Gram-positive pathogens, with an average cost per case of 211.03 U.S. dollars (USD) for Gram-negative bacterial infections compared with 133.73 USD for Gram-positive bacterial CM cases. After Escherichia coli, K. pneumoniae is the second most common Gram-negative cause of bovine CM, but it is the most detrimental in terms of decreased milk yield, discarded milk, treatment costs, death, and culling. In view of the economic implications of K. pneumoniae infection in dairy farming, research into population structure and antibiotic resistance is particularly important.

Investigation of ceftazidime-avibactam susceptibility in clinical isolates of gram-negative bacteria

BACKGROUND

Our study investigated the susceptibility rate of ceftazidime-avibactam and the risk factors associated with its resistance by analyzing gram-negative bacteria isolated from various patient samples.

METHODS

Between March and November 2020, 1119 gram-negative bacteria strains were isolated from patient samples in Acıbadem Healthcare Group hospitals; ceftazidime-avibactam susceptibility results were evaluated using a 10/4µg (Oxoid, UK) disc and evaluated according to Eucast 2020 recommendations. Patient and isolate characteristics that could be risk factors were retrospectively investigated and statistically analyzed using SPSS 25.0.

RESULTS

Male patients made up 52% (n = 581) of the study's total patient population, and they averaged 55.5 ± 24.9 years old. Of 1119 gram-negative strains culture and antibiogram, 1023 (91.4%) were sensitive to ceftazidime-avibactam. An increased risk of resistance was observed with female gender (OR = 2.29; CI 95% [1.45-3.61]; p < 0.05), Pseudomonas aeruginosa (OR = 1.67, CI 95% [1.03-2.7]; p < 0.05), the presence of multidrug-resistance (MDR) (OR = 4.07, CI 95% [2.47-6.7]; p < 0.05) pandrug-resistance (PDR) (OR = 12, (CI) 95% [9.9-14.7] ]; p < 0.05) and admission to intensive care unit (ICU) (OR = 1.89, CI 95% [1.22-2.93]; p < 0.05).

DISCUSSION

The resistance rate of ceftazidime-avibactam was found to be 8.6%, and it was thought that resistant strains produced metallo-ß-lactamase (MBL) type carbapenemase. Risk factors were female gender, Pseudomonas aeruginosa, MDR, PDR, and admission to ICU. Therefore, studying the ceftazidime-avibactam susceptibility test together with gram-negative bacteria identification, especially in groups at risk for resistance, is one of the important factors that can positively affect the success of treatment.

Carbapenem-Resistant Gram-Negative Fermenting and Non-Fermenting Rods Isolated from Hospital Patients in Poland-What Are They Susceptible to?

Gram-negative fermenting and non-fermenting bacteria are important etiological factors of nosocomial and community infections, especially those that produce carbapenemases. Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are the most frequently-detected carbapenemase-producing microorganisms. The predominant type of resistance is metallo-β-lactamase (MBL). These bacteria are predominantly isolated from bronchial alveolar lavage, urine, and blood. Carbapenemase-producing Enterobacterales (CPE) strains are always multi-drug-resistant. This significantly limits the treatment options for this type of infection, extends the time of patient hospitalization, and increases the risk of a more severe and complicated disease course. Preventing the transmission of these microorganisms should be a major public health initiative. New antibiotics and treatment regimens offer hope against these infections.

In silico characterization of bla NDM-harboring plasmids in Klebsiella pneumoniae

Klebsiella pneumoniae is a primary culprit of antibiotic-resistant nosocomial infections worldwide, and infections caused by NDM-producing strains are a major threat due to limited therapeutic options. The majority of bla _NDM cases occur on plasmids; therefore, we explored the relationships between plasmids and bla _NDM genes in K. pneumoniae by analyzing the variants of bla _NDM, replicon types, conjugative transfer regions of 171 bla _NDM-harboring plasmids from 4,451 K. pneumoniae plasmids. Of the nine identified bla _NDM variants, bla _NDM-1 (73.68%) and bla _NDM-5 (16.37%) were the most dominant. Over half of the bla _NDM-harboring plasmids of K. pneumoniae were classified into IncF plasmids. IncX3 single-replicon plasmids (46-57 kb) carried genes encoding relaxases of the MOB_P family, T4CP genes of the VirD4/TraG subfamily, and VirB-like T4SS gene clusters, which were mainly geographically distributed in China. We found 10 bla _NDM-harboring IncN plasmids (38.38-63.05 kb) carrying the NW-type origin of transfer (oriT) regions, genes coding for relaxases of MOB_F family, genes encoding T4CPs of the TrwB/TraD subfamily, and Trw-like T4SS gene clusters, which were also mainly geographically distributed in China. Moreover, we identified 21 IncC plasmids carrying bla _NDM-1 (140.1-329.2 kb), containing the A/C-type oriTs, genes encoding relaxases of MOB_H family, genes encoding T4CPs belonging to TrwB/TraD subfamily, and Tra_F-like T4SS gene clusters. The bla _NDM-harboring IncC plasmids were widely geographically distributed all over the world, mainly in the United States, China and Viet Nam. These findings enhance our understanding of the diversity of bla _NDM-harboring plasmids in K. pneumoniae.

Outbreak of KPC-producing Klebsiella pneumoniae at a Portuguese university hospital: Epidemiological characterization and containment measures

Background

KPC-producing K pneumoniae (KPC-Kp) is a public health problem with important clinical and epidemiological implications. We describe an outbreak of KPC-Kp at vascular surgery and neurosurgery wards in a central hospital in Porto, Portugal.

Methods

A case of KPC-Kp was considered to be a patient positive for KPC-Kp with strong epidemiological plausibility of having acquired this microorganism in the affected wards and/or with genetic relationship ≥92% between KPC-Kp isolates. Active surveillance cultures (ASCs) and real-time polymerase chain reaction were used for the detection of carbapenemase genes through rectal swab in a selected population. Molecular analysis was performed using pulsed-field gel electrophoresis at the National Reference Laboratory. Patient risk factors were collected from the electronic medical record system. Information regarding outbreak containment strategy was collected from the Infection Control Unit records.

Results

Of the 16 cases, 11 (69%) were identified through active screening, representing 1.4% of the total 766 ASCs collected. The most frequent risk factors identified were previous admission (63%), antibiotic exposure in the past 6 months (50%), and immunodepression (44%). The length of stay until KPC-Kp detection was high (0-121 days, mean 35.6), as was the total length of stay (5-173 days, mean 56.6). Three patients (19%) were infected by KPC-Kp, 2 of whom died. One previously colonized patient died later because of KPC-Kp infection.

Conclusions

Multifactorial strategy based on contact precautions (with patient and healthcare professional cohorts) and ASC, as well as Antibiotic Stewardship Program reinforcement, allowed to contain this KPC-Kp outbreak.

A Seven-Year Microbiological and Molecular Study of Bacteremias Due to Carbapenemase-Producing Klebsiella Pneumoniae: An Interrupted Time-Series Analysis of Changes in the Carbapenemase Gene's Distribution after Introduction of Ceftazidime/Avibactam

Background: Ceftazidime/avibactam (CZA) is a new option for the treatment of KPC-producing Klebsiella pneumoniae. The aim of this study was to determine resistance patterns and carbapenemase genes among K. pneumoniae (CP-Kp) bacteremic isolates before and after CZA introduction. Methods: K. pneumoniae from blood cultures of patients being treated in a Greek university hospital during 2015−21 were included. PCR for blaKPC, blaVIM, blaNDM and blaOXA-48 genes was performed. Results: Among 912 K. pneumoniae bacteremias: 725 (79.5%) were due to carbapenemase-producing isolates; 488 (67.3%) carried blaKPC; 108 (14.9%) blaVIM; 100 (13.8%) blaNDM; and 29 (4%) carried a combination of blaKPC, blaVIM or blaNDM. The incidence of CP-Kp bacteremias was 59 per 100,000 patient-days. The incidence of CP-Kp changed from a downward pre-CZA trend to an upward trend in the CZA period (p = 0.007). BSIs due to KPC-producing isolates showed a continuous downward trend in the pre-CZA and CZA periods (p = 0.067), while BSIs due to isolates carrying blaVIM or blaNDM changed from a downward trend in the pre-CZA to an upward trend in the CZA period (p < 0.001). Conclusions: An abrupt change in the epidemiology of CP-Kp was observed in 2018, due to the re-emergence of VIM-producing isolates after the suppression of KPC-producing ones via the use of CZA.

Occurrence of Healthcare-Associated Infections (HAIs) by Escherichia coli and Klebsiella spp. Producing Extended-Spectrum β-lactamases (ESBL) and/or Carbapenemases in Portuguese Long-Term Care Facilities

Extended-spectrum-β-lactamase (ESBL)- and carbapenemase-producing bacteria are widespread in hospitals, but the extent of this problem in long-term care facilities (LTCFs) is poorly understood. We aimed to elucidate, in the Portuguese regional clinical context, the relevance of LTCFs as a reservoir of Escherichia coli and Klebsiella spp. producing ESBL- and/or carbapenemases (Ec/Kp-ESBL/CARB). Fourteen LTCFs from Portugal, corresponding to units of convalescence (UC/n = 3), medium-term internment and rehabilitation (UMDR/ n = 5), or long-term internment and maintenance (ULDM/n = 6), were analyzed (2016–2019). All patients with Ec/Kp-ESBL/CARB infections acquired during LTCF stay were included, and detailed information was collected. Prevalence of patients with healthcare-associated infections (HAIs) by Ec/Kp-ESBL/CARB did not vary significantly over time (1.48% in 2016–2017, 1.89% in 2017–2018, and 1.90% in 2018–2019), but a statistically significant association with the LTCF typology (ULDM, UMDR) was observed. HAIs were caused by K. pneumoniae (n = 51/54.3%), E. coli (n = 41/43.6%), or both (n = 2/2.1%), producing ESBL (96%) or carbapenemases (4%). Prior colonization (n = 14/16%) corresponded to seven Kp-CARB and seven Ec/Kp-ESBL. The worrying prevalence of patients acquiring HAIs by Ec/Kp-ESBL/CARB, associated with the estimated rates of those already colonized at admission, highlights a relevant role for LTCFs as a reservoir of Ec/Kp-ESBL/CARB. Epidemiological surveillance should be extended to the national level, and colonization screening at LTCF admission implemented systematically.

Microbial epidemiology and clinical risk factors of carbapenemase-producing Enterobacterales amongst Irish patients from first detection in 2009 until 2020

Background

Carbapenemase producing Enterobacterales (CPE) are major public health threats.

Aim

To review microbial epidemiology of CPE, as well as clinical risk factors and infections, amongst CPE positive patients over 12 years in an Irish tertiary hospital.

Methods

Retrospective observational study of data extracted from a laboratory CPE database, electronic healthcare records and manual review of patient charts. Common risk factors, treatment regimens for all CPE related infections, and clinical outcomes were ascertained.

Findings

Among CPE strains isolated from 460 patients, Klebsiella pneumoniae carbapenemase (KPC) was the carbapenemase most frequently detected, accounting for 87.4% (459) of all CPE enzymes. Citrobacter species 177 (33.7%) were the most common species harbouring this enzyme. 428 CPE positive patients (93%) were identified in the acute hospital setting; the most common risk factor for CPE acquisition was history of hospitalisation, observed in 305 (66%) cases. Thirty patients (6.5%) had confirmed infections post-acquisition, of which four were bloodstream infections. There were 19 subsequent episodes of non CPE-related bacteraemia in this cohort. All causal mortality at 30 days was 41 patients (8.9%). However, clinical review determined that CPE was an indirect associative factor in 8 patient deaths.

Conclusions

In this tertiary hospital setting, microbial epidemiology is changing; with both OXA-48 enzymes and KPC-producing Citrobacter species becoming more prevalent. Whilst the burden of CPE related infections, especially bacteraemia, was low over the study period, it remains critical that basic infection prevention and control practices are adhered to lest the observed changes in epidemiology result in an increase in clinical manifestations.

OXA-48-Like β-Lactamases: Global Epidemiology, Treatment Options, and Development Pipeline

Modern medicine is threatened by the rising tide of antimicrobial resistance, especially among Gram-negative bacteria, where resistance to β-lactams is most often mediated by β-lactamases. The penicillin and cephalosporin ascendancies were, in their turn, ended by the proliferation of TEM penicillinases and CTX-M extended-spectrum β-lactamases. These class A β-lactamases have long been considered the most important. For carbapenems, however, the threat is increasingly from the insidious rise of a class D carbapenemase, OXA-48, and its close relatives. Over the past 20 years, OXA-48 and "OXA-48-like" enzymes have proliferated to become the most prevalent enterobacterial carbapenemases across much of Europe, Northern Africa, and the Middle East. OXA-48-like enzymes are notoriously difficult to detect because they often cause only low-level in vitro resistance to carbapenems, meaning that the true burden is likely underestimated. Despite this, they are associated with carbapenem treatment failures. A highly conserved incompatibility complex IncL plasmid scaffold often carries bla_OXA-48 and may carry other antimicrobial resistance genes, leaving limited treatment options. High conjugation efficiency means that this plasmid is sometimes carried by multiple Enterobacterales in a single patient. Producers evade most β-lactam-β-lactamase inhibitor combinations, though promising agents have recently been licensed, notably ceftazidime-avibactam and cefiderocol. The molecular machinery enabling global spread, current treatment options, and the development pipeline of potential new therapies for Enterobacterales that produce OXA-48-like β-lactamases form the focus of this review.

Enabling value-in-use with digital healthcare technologies: combining service logic and pragmatic constructivism

The paper discusses how healthcare providers can enable value-in-use (VIU) using digital technologies in complex healthcare service contexts. Technology providers and public healthcare organizations can have difficulties understanding one another, hindering the possibilities for value-in-use to emerge. Plenty of studies have investigated the value creation in healthcare, often looking at health as value for the patient. We focus on how healthcare providers can create value for themselves to improve their operations and justify the price of new technologies while fully acknowledging the value for the patient as well. The paper uses two in-depth interventionist case studies in Nordic health care: automated screening technology for hospital laboratories and medicine dispensing robotics for home care. We use a novel combination of pragmatic constructivism (PC) and service logic (SL) as method theories to understand the value creation in our cases. Our empirical evidence provide practical examples of how digital technologies can be used to change healthcare practices and how VIU can stem from these changes. As a contribution, we show that healthcare providers can enable value-in-use with digital technologies by altering how care is carried out without hindering what the outcome of the care is for the patient. Digital technologies are there to facilitate such change, but the change still requires that actors involved in care have intention to change how they work. While healthcare bears the responsibility for these changes, technology providers can also have plenty of opportunities for interaction to support or even co-create value together with their customers.

Azithromycin possesses biofilm–inhibitory activity and potentiates non-bactericidal colistin methanesulfonate (CMS) and polymyxin B against Klebsiella pneumonia

Novel antibiotic combinations may act synergistically to inhibit the growth of multidrug-resistant bacterial pathogens but predicting which combination will be successful is difficult, and standard antimicrobial susceptibility testing may not identify important physiological differences between planktonic free-swimming and biofilm-protected surface-attached sessile cells. Using a nominally macrolide-resistant model Klebsiella pneumoniae strain (ATCC 10031) we demonstrate the effectiveness of several macrolides in inhibiting biofilm growth in multi-well plates, and the ability of azithromycin (AZM) to improve the effectiveness of the antibacterial last-agent-of-choice for K. pneumoniae infections, colistin methanesulfonate (CMS), against biofilms. This synergistic action was also seen in biofilm tests of several K. pneumoniae hospital isolates and could also be identified in polymyxin B disc-diffusion assays on azithromycin plates. Our work highlights the complexity of antimicrobial-resistance in bacterial pathogens and the need to test antibiotics with biofilm models where potential synergies might provide new therapeutic opportunities not seen in liquid culture or colony-based assays.

In vitro activity of aztreonam/avibactam against isolates of Enterobacterales collected globally from ATLAS in 2019

OBJECTIVES

Infections caused by drug-resistant Enterobacterales including those producing metallo-β-lactamases (MBLs) are particularly challenging due to limited therapeutic options. The drug combination aztreonam/avibactam (ATM-AVI) is under clinical development for treating serious infections caused by these strains. This study assessed the in vitro activity of ATM-AVI against Enterobacterales isolates collected globally in the ATLAS surveillance programme in 2019.

METHODS

Clinical isolates of Enterobacterales (N=18713) including Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, and Serratia marcescens collected from 232 sites in 2019 were analysed. Antimicrobial susceptibility testing was performed by reference broth microdilution. A pharmacokinetic/pharmacodynamic based breakpoint of 8 mg/L was considered for ATM-AVI activity.

RESULTS

ATM-AVI demonstrated potent antimicrobial activity against all Enterobacterales, with 99.9% isolates inhibited at MIC ≤8 mg/L (MIC₉₀, 0.25 mg/L). MICs ≤8 mg/L (>99.0%) were noted for ATM-AVI across regions worldwide. Among other antimicrobials, amikacin, colistin, imipenem, meropenem, and tigecycline were also active (susceptibility >85.0%) against Enterobacterales. Activity of ATM-AVI was sustained against multi-drug resistant, extended-spectrum β-lactamases producing, and carbapenem-resistant isolates (susceptibility >99%; MIC₉₀, 0.25-0.5 mg/L). Importantly, potent activity for ATM-AVI (>99.0%; MIC_90, 0.5 mg/L) was noted among MBL-positive isolates and those producing other carbapenemases, such as KPC and OXA-48.

CONCLUSIONS

Our results demonstrated that ATM-AVI was highly active against a recent collection of Enterobacterales isolates, including those producing MBLs either alone or in combination with other carbapenemases. Thus, ATM-AVI represents a potential option for treating infections caused by antibiotic-resistant Enterobacterales including MBL-producing strains.

Global Distribution of Extended Spectrum Cephalosporin and Carbapenem Resistance and Associated Resistance Markers in Escherichia coli of Swine Origin - A Systematic Review and Meta-Analysis

Third generation cephalosporins and carbapenems are considered critically important antimicrobials in human medicine. Food animals such as swine can act as reservoirs of antimicrobial resistance (AMR) genes/bacteria resistant to these antimicrobial classes, and potential dissemination of AMR genes or resistant bacteria from pigs to humans is an ongoing public health threat. The objectives of this systematic review and meta-analysis were to: (1) estimate global proportion and animal-level prevalence of swine E. coli phenotypically resistant to third generation cephalosporins (3GCs) and carbapenems at a country level; and (2) measure abundances and global distribution of the genetic mechanisms that confer resistance to these antimicrobial classes in these E. coli isolates. Articles from four databases (CAB Abstracts, PubMed/MEDLINE, PubAg, and Web of Science) were screened to extract relevant data. Overall, proportion of E. coli resistant to 3GCs was lower in Australia, Europe, and North America compared to Asian countries. Globally, <5% of all E. coli were carbapenem-resistant. Fecal carriage rates (animal-level prevalence) were consistently manifold higher as compared to pooled proportion of resistance in E. coli isolates. bla_CTX–M were the most common 3GC resistance genes globally, with the exception of North America where bla_CMY were the predominant 3GC resistance genes. There was not a single dominant bla_CTX–M gene subtype globally and several bla_CTX–M subtypes were dominant depending on the continent. A wide variety of carbapenem-resistance genes (bla_{NDM–, VIM–, IMP–, OXA–48}, _andKPC–) were identified to be circulating in pig populations globally, albeit at very-low frequencies. However, great statistical heterogeneity and a critical lack of metadata hinders the true estimation of prevalence of phenotypic and genotypic resistance to these antimicrobials. Comparatively frequent occurrence of 3GC resistance and emergence of carbapenem resistance in certain countries underline the urgent need for improved AMR surveillance in swine production systems in these countries.

Diversity of carbapenemase-producing Enterobacterales in England as revealed by whole-genome sequencing of isolates referred to a national reference laboratory over a 30-month period

Introduction. Increasing numbers of carbapenemase-producing Enterobacterales (CPE), which can be challenging to treat, have been referred to the national reference laboratory in England since the early 2000s.Gap Statement/Aim. Previous studies on CPE in the UK have focussed on localized outbreaks. We applied whole-genome sequencing (WGS) to isolates referred to the national reference laboratory over 30 months to inform our understanding of CPE epidemiology in England.Methodology. The first confirmed CPE from each new patient referred by an English diagnostic laboratory between 1 January 2014 and 30 June 2016 was sequenced on an Illumina HiSeq 2500. Multiple isolates from the same patient were included from either different species or the same species with different carbapenemase genes. The data were analysed using an in-house bioinformatics pipeline that determines species identification, multi-locus sequence typing (MLST) profile and antimicrobial resistance gene content.Results. A total of 2658 non-duplicate CPE were sequenced amongst which three host organisms belonging to diverse sequence types (STs) predominated: Klebsiella pneumoniae (1380/2658, 51.9 %; 177 STs), Escherichia coli (723/2658, 27.2 %; 133 STs) and Enterobacter cloacae (294/2658, 11.1 %; 88 STs). Thirty different carbapenemase gene variants were identified, although bla _OXA-48-like (1122/2658, 42.2%), bla _NDM (692/2658, 26.0 %), bla _KPC (571/2658, 21.5 %), bla _VIM (100/2658, 3.8 %) and bla _IMP (33/2658, 1.2 %) predominated. ST/carbapenemase gene pairings represented widely distributed high-risk clones or clusters at a regional or hospital level.Conclusion. CPE referred to the national reference laboratory are diverse, suggesting multiple introductions to England and a role for horizontal transfer of carbapenemase genes in English CPE epidemiology.

Epidemiological Characteristics of Carbapenemase Producing Carbapenem-Resistant Enterobacteriaceae Colonization

PURPOSE

This study identified the epidemiological characteristics, including the size and major strains, of carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) and CP-CRE-related factors by comparing the characteristics of patients in the CP-CRE and non-CP-CRE groups and the CP-CRE and non-CRE groups.

METHODS

This secondary data analysis study included 24 patients in the CP-CRE group, 113 patients in the non-CP-CRE group, and 113 in the non-CRE group. The size and type of CP-CRE were analyzed in terms of frequency and percentage, and CP-CRE risk factors were identified using multiple logistic regression analysis.

RESULTS

The rate of CP-CRE positivity among patients with CRE was 17.5%, and the most common causative organism in the CP-CRE group was Klebsiella pneumoniae (81.8%). There were no significant differences between patients in the CP-CRE and non-CP-CRE groups. When compared with the non-CRE group, the isolation of multidrug-resistant organisms except for CRE, particularly vancomycin resistant Enterococcus, was confirmed as a major risk factor.

CONCLUSION

To prevent CP-CRE acquisition, patients with multidrug-resistant organisms require treatment with more thorough adherence to CRE prevention and management guidelines.

Epidemiology of carbapenem-resistant and carbapenemase-producing Enterobacterales in the Netherlands 2017-2019

Background

The Netherlands is currently considered a low endemic country for carbapenem-resistant Enterobacterales (CRE) and carbapenemase-producing Enterobacterales (CPE), experiencing only sporadic hospital outbreaks. This study aims to describe susceptibility to carbapenems and the epidemiology of carbapenemase production in Enterobacterales in the Netherlands in 2017–2019.

Methods

Three complementary nationwide surveillance systems are in place to monitor carbapenem susceptibility in the Netherlands. Routine antimicrobial susceptibility test results from medical microbiology laboratories were used to study phenotypic susceptibility of Escherichia coli and Klebsiella pneumoniae. Pathogen surveillance (of all Enterobacterales species) and mandatory notifications were used to describe the characteristics of CPE positive isolates and affected persons.

Results

The prevalence of isolates with gradient strip test-confirmed elevated meropenem (> 0.25 mg/L) or imipenem (> 1 mg/L) minimum inhibitory concentration (MIC) in the Netherlands was very low in 2017–2019, with percentages of 0.06% in E. coli and 0.49% in K. pneumoniae, and carbapenem resistances of 0.02% and 0.18%, respectively. A total of 895 unique species/carbapenemase-encoding allele combinations of CPE from 764 persons were submitted between 2017 and 2019, with the annual number of submissions increasing slightly each year. Epidemiological data was available for 660 persons. Screening because of presumed colonisation risk was the reason for sampling in 70.0% (462/660) of persons. Hospitalization abroad was the most common risk factor, being identified in 45.9% of persons.

Conclusions

Carbapenem resistance of E. coli and K. pneumoniae remains low in the Netherlands. The annual number of CPE isolates slightly increased during the period 2017–2019. Recent hospitalization abroad is the main risk factor for acquisition of CPE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01097-9.

The effect of a full-time infection control nursing service in the prevention of multidrug-resistant organism in the orthopedic ward

Background

Our aim was to evaluate the effect of setting up a full-time infection control nursing service on reducing the prevalence of multidrug-resistant organism (MDRO) in the orthopedic ward.

Methods

From January 2015 to March 2019, routine prevention and control measures were taken for patients infected/colonized with MDRO in this ward, which was set as the pre-intervention period. The intervention period was from April 2019 to June 2021. The study was designed to evaluate whether the establishment of a full-time infection control nursing service could reduce the positive density of MDRO in the hospital by using an interrupted time-series model of a quasi experimental study.

Results

There were 11,759 patients during pre-intervention period and 8142 patients during intervention period. The total number of MDRO isolated before intervention was 177, of which 145 were obtained in hospital and 32 were brought in from outside hospital. The total number of MDRO isolated after intervention was 47, of which 29 were obtained in hospital and 18 were brought in from outside hospital. Before intervention, the positive density of MDRO in the orthopedic ward showed an increasing trend (β₁ = 0.02, P = 0.003). After intervention, the positive density of MDRO showed a downward trend (β₃ = − 0.05, P = 0.018).

Conclusions

The establishment of the full-time infection control nursing service in the orthopedic ward can effectively reduce the nosocomial prevalence of MDRO.

Comparison of Six Phenotypic Assays with Reference Methods for Assessing Colistin Resistance in Clinical Isolates of Carbapenemase-Producing Enterobacterales: Challenges and Opportunities

The global escalation of severe infections due to carbapenemase-producing Enterobacterales (CPE) isolates has prompted increased usage of parenteral colistin. Considering the reported difficulties in assessing their susceptibility to colistin, the purpose of the study was to perform a comparative evaluation of six phenotypic assays—the colistin broth disc elution (CBDE), Vitek 2 Compact (bioMérieux SA, Marcy l’Etoile, France), the Micronaut MIC-Strip Colistin (Merlin Diagnostika GMBH, Bornheim-Hensel, Germany), the gradient diffusion strip Etest (bioMérieux SA, Marcy l’Etoile, France), ChromID Colistin R Agar (COLR) (bioMérieux SA, Marcy l’Etoile, France), and the Rapid Polymyxin NP Test (ELITechGroup, Signes, France)—versus the reference method of broth microdilution (BMD). All false resistance results were further assessed using population analysis profiling (PAP). Ninety-two nonrepetitive clinical CPE strains collected from two hospitals were evaluated. The BMD confirmed 36 (39.13%) isolates susceptible to colistin. According to the BMD, the Micronaut MIC-Strip Colistin, the CBDE, and the COLR medium exhibited category agreement (CA) of 100%. In comparison with the BMD, the highest very major discrepancy (VMD) was noted for Etest (n = 15), and the only false resistance results were recorded for the Rapid Polymyxin NP Test (n = 3). Only the PAP method and the Rapid Polymyxin NP Test were able to detect heteroresistant isolates (n = 2). Thus, there is an urgent need to further optimize the diagnosis strategies for colistin resistance.

Quantitative Risk Assessment for the Introduction of Carbapenem-Resistant Enterobacteriaceae (CPE) into Dutch Livestock Farms

Early detection of emerging carbapenem-resistant Enterobacteriaceae (CPE) in food-producing animals is essential to control the spread of CPE. We assessed the risk of CPE introduction from imported livestock, livestock feed, companion animals, hospital patients, and returning travelers into livestock farms in The Netherlands, including (1) broiler, (2) broiler breeder, (3) fattening pig, (4) breeding pig, (5) farrow-to-finish pig, and (6) veal calf farms. The expected annual number of introductions was calculated from the number of farms exposed to each CPE source and the probability that at least one animal in an exposed farm is colonized. The total number of farms with CPE colonization was estimated to be the highest for fattening pig farms, whereas the probability of introduction for an individual farm was the highest for broiler farms. Livestock feed and imported livestock are the most likely sources of CPE introduction into Dutch livestock farms. Sensitivity analysis indicated that the number of fattening pig farms determined the number of high introductions in fattening pigs from feed, and that uncertainty on CPE prevalence impacted the absolute risk estimate for all farm types. The results of this study can be used to inform risk-based surveillance for CPE in livestock farms.

Massive Spread of OXA-48 Carbapenemase-Producing Enterobacteriaceae in the Environment of a Swiss Companion Animal Clinic

Background: Companion animal clinics contribute to the spread of antimicrobial resistant microorganisms (ARM) and outbreaks with ARM of public health concern have been described. Methods: As part of a project to assess infection prevention and control (IPC) standards in companion animal clinics in Switzerland, a total of 200 swabs from surfaces and 20 hand swabs from employees were collected during four days in a medium-sized clinic and analyzed for extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E), carbapenemase-producing Enterobacteriaceae (CPE), vancomycin-resistant enterococci (VRE), and methicillin-resistant staphylococci (MRS). Results: A total of 22 (11.0%) environmental specimen yielded CPE, 14 (7.0%) ESBL-E, and 7 (3.5%) MRS; MR Staphylococcus aureus were isolated from two (10.0%) hand swabs. The CPE isolates comprised Escherichia coli, Klebsiella pneumoniae, Enterobacter hormaechei, Citrobacter braakii, and Serratia marcescens. Whole genome sequencing revealed that all CPE carried closely related bla_OXA-48 plasmids, suggesting a plasmidic spread within the clinic. The clinic exhibited major deficits in surface disinfection, hand hygiene infrastructure, and hand hygiene compliance. CPE were present in various areas, including those without patient contact. The study documented plasmidic dissemination of bla_OXA-48 in a companion animal clinic with low IPC standards. This poses a worrisome threat to public health and highlights the need to foster IPC standards in veterinary clinics to prevent the spread of ARM into the community.

Overcoming the rising incidence and evolving mechanisms of antibiotic resistance by novel drug delivery approaches - An overview

Antimicrobial resistance is a normal evolutionary process for microorganisms. Antibiotics exerted accelerated selective pressure that hasten bacterial resistance through mutation, and acquisition external genes. These genes often carry multiple antibiotic resistant determinants allowing the recipient microbe an instant "super-bug" status. The extent of Antimicrobial Resistance (AMR) has reached a level of global crisis, existing antimicrobials are no long effective in treating infections caused by AMR pathogens. The great majority of clinically available antimicrobial agents are administered through oral and intra-venous routes. Overcoming antibacterial resistance by novel drug delivery approach offered new hopes, particularly in the treatment of AMR pathogens in sites less assessible through systemic circulation such as the lung and skin. In the current review, we will revisit the mechanism and incidence of important AMR pathogens. Finally, we will discuss novel drug delivery approaches including novel local antibiotic delivery systems, hybrid antibiotics, and nanoparticle-based antibiotic delivery systems.

Plethora of Resistance Genes in Carbapenem-Resistant Gram-Negative Bacteria in Greece: No End to a Continuous Genetic Evolution

Carbapenem-resistant Gram-negative bacteria are a public health threat that requires urgent action. The fact that these pathogens commonly also harbor resistance mechanisms for several other antimicrobial classes further reduces patient treatment options. The present study aimed to provide information regarding the multidrug resistance genetic background of carbapenem-resistant Gram-negative bacteria in Central Greece. Strains from a tertiary care hospital, collected during routine practice, were characterized using a DNA microarray-based assay. Various different resistance determinants for carbapenems, other beta-lactams, aminoglycosides, quinolones, trimethoprim, sulfonamides and macrolides were detected among isolates of the same sequence type. Eighteen different multidrug resistance genomic profiles were identified among the twenty-four K. pneumoniae ST258, seven different profiles among the eight K. pneumoniae ST11, four profiles among the six A. baumannii ST409 and two among the three K. oxytoca. This report describes the multidrug resistance genomic background of carbapenem-resistant Gram-negative bacteria from a tertiary care hospital in Central Greece, providing evidence of their continuous genetic evolution.

Prevalence and zoonotic transmission of colistin-resistant and carbapenemase-producing Enterobacterales on German pig farms

The treatment of infections due to colistin-resistant (Col-E) and carbapenemase-producing (CPE) Enterobacterales challenges clinicians both in human and veterinary medicine. Preventing zoonotic transmission of these multidrug-resistant bacteria is a Public Health priority. This study investigates the prevalence of Col-E and CPE on 81 pig farms in North-West Germany as well as among 138 directly exposed humans working on these farms. Between March 2018 and September 2020, 318 samples of porcine feces were taken using boot swabs. Farm workers provided a stool sample. Both a selective culture-based approach and a molecular detection of colistin (mcr-1 to mcr-5) and carbapenem resistance determinants (bla _OXA-48/bla _VIM/bla _KPC/bla _NDM) was used to screen all samples. Isolates from farm workers and farms were compared using core genome multilocus-sequence typing (cgMLST) and plasmid-typing. CPE were cultured neither from porcine feces nor from human stool samples. In one stool sample, bla _OXA-48 was detected, but no respective CPE isolate was found. Col-E were found in 18/318 porcine (5.7%) samples from 10/81 (12.3%) farms and 2/138 (1.4%) farmers, respectively. All Col-E isolates were Escherichia coli harboring mcr-1. Both farm workers colonized with Col-E worked on farms where no Col-E were detected in porcine samples. In conclusion, CPE were absent on German pig farms. This supports findings of culture-based national monitoring systems and provides evidence that even when improving the diagnostic sensitivity by using molecular detection techniques in addition to culture, CPE are not prevalent. Col-E were prevalent in porcine feces despite a recent decrease in colistin usage among German livestock and absence of colistin treatments on the sampled farms. Farmers carried Col-E, but zoonotic transmission was not confirmed.

Genetic Diversity and Characteristics of bla NDM-Positive Plasmids in Escherichia coli

New Delhi metallo-β-lactamases (NDMs), including at least 28 variants, are a rapidly emerging family of β-lactamases worldwide, with a variety of infections caused by NDM-positive strains usually associated with very poor prognosis and high mortality. NDMs are the most prevalent carbapenemases in Escherichia coli (E. coli) worldwide, especially in China. The vast majority of bla_NDM cases occur on plasmids, which play a vital role in the dissemination of bla_NDM. To systematically explore the relationships between plasmids and bla_NDM genes in E. coli and obtain an overall picture of the conjugative and mobilizable bla_NDM-positive plasmids, we analyzed the variants of bla_NDM, replicon types, phylogenetic patterns, conjugative transfer modules, host STs, and geographical distributions of 114 bla_NDM-positive plasmids, which were selected from 3786 plasmids from 1346 complete whole genomes of E. coli from the GenBank database. We also established links among the characteristics of bla_NDM-positive plasmids in E. coli. Eight variants of bla_NDM were found among the 114 bla_NDM-positive plasmids, with bla_NDM–5 (74 bla_NDM–5 genes in 73 plasmids), and bla_NDM–1 (31 bla_NDM–1 genes in 28 plasmids) being the most dominant. The variant bla_NDM–5 was mainly carried by the IncX3 plasmids and IncF plasmids in E. coli, the former were mainly geographically distributed in East Asia (especially in China) and the United States, and the latter were widely distributed worldwide. IncC plasmids were observed to be the predominant carriers of bla_NDM–1 genes in E. coli, which were mainly geographically distributed in the United States and China. Other bla_NDM–1-carrying plasmids also included IncM2, IncN2, and IncHI1. Moreover, the overall picture of the conjugative and mobilizable bla_NDM-positive plasmids in E. coli was described in our study. Our findings enhance our understanding of the genetic diversity and characteristics of bla_NDM-positive plasmids in in E. coli.

Differences in antimicrobial susceptibility testing complicating management of IMP carbapenemase-producing Enterobacterales infection

OBJECTIVES

IMP-type carbapenemases are rarely detected in Europe and limited information is available to guide the treatment of infections caused by carbapenemase-producing Enterobacterales (CPE) producing these carbapenemases. Accurate antimicrobial susceptibility testing (AST) results are essential for optimal antibiotic management. Here we report discrepancies in AST of IMP-producing Enterobacterales (IMP-CPE) complicating the management of severe sepsis.

METHODS

Antimicrobial susceptibilities were analysed by in-house VITEK® 2, Etest and broth microdilution (BMD). Carbapenemase-encoding genes were detected by PCR. Whole-genome sequencing (WGS) was performed using an Illumina MiSeq platform.

RESULTS

Minimum inhibitory concentrations (MICs) determined by VITEK® 2 for Enterobacter hormaechei and Klebsiella oxytoca blood culture isolates were ≥16 mg/L for meropenem and ≤0.5 mg/L for ertapenem. In contrast, Etest analysis and BMD returned MICs of 2 mg/L and 1 mg/L, respectively. Both isolates tested positive for IMP carbapenemase-encoding genes by PCR. WGS revealed that both isolates carried the same bla_IMP-4 gene. Based on VITEK® 2 susceptibilities, initial treatment was with tigecycline and amikacin. After subsequent deterioration, the patient was successfully treated with ertapenem and amikacin.

CONCLUSION

This case highlights that automated AST by VITEK® 2 can over-report meropenem resistance for IMP carbapenemase-producers compared with Etest and BMD. Clinicians need to be cautious deciding against carbapenem treatment based on VITEK® 2 susceptibility testing results for IMP-positive Enterobacterales. Tigecycline was inferior to carbapenem treatment for pyelonephritis caused by isolates expressing IMP carbapenemases, however specific evidence guiding the treatment of these infections is lacking.

Screening for Antimicrobial-Resistant Gram-negative bacteria in hospitalised patients, and risk of progression from colonisation to infection: Systematic review

BACKGROUND

Transmission of antimicrobial-resistant Gram-negative bacteria (AMR-GNB) among hospitalised patients can lead to new cases of carriage, infection and outbreaks, hence the need for early carrier identification. We aim to explore two key elements that may guide control policies for colonisation/infection in hospital settings: screening practices on admission to hospital wards and risk of developing infection from colonisation.

METHODS

We searched on PubMed, Scopus and Cochrane databases for studies published from 2010 up to 2021 reporting on adult patients hospitalised in high-income countries.

RESULTS

The search retrieved 11853 articles. After screening, 100 studies were included. Combining target patient groups and setting type, we identified six screening approaches. The most reported approach was all admitted patients to high-risk (HR) wards (49.4%). The overall prevalence of AMR-GNB was 13.8% (95%CI 9.3-19.0) with significant differences across regions and time. Risk of progression to infection among colonised patients was 11.0% (95%CI 8.0-14.3) and varied according to setting and pathogens' group (p value<0.0001), with higher values reported for Klebsiella species (18.1%; 95%CI 8.9-29.3).

CONCLUSIONS

While providing a comprehensive overview of the screening approaches, our study underlines the considerable burden of AMR-GNB colonisation and risk of progression to infection in hospitals by pathogen, setting and time.

Global colistin use: A review of the emergence of resistant Enterobacterales and the impact on their genetic basis

The dramatic global rise of MDR and XDR Enterobacterales in human medicine forced clinicians to the reintroduction of colistin as last-resort drug. Meanwhile, colistin is used in the veterinary medicine since its discovery, leading to a steadily increasing prevalence of resistant isolates in the livestock and meat-based food sector. Consequently, transmission of resistant isolates from animals to humans, acquisition via food and exposure to colistin in the clinic are reasons for the increased prevalence of colistin-resistant Enterobacterales in humans in the last decades. Initially, resistance mechanisms were caused by mutations in chromosomal genes. However, since the discovery in 2015, the focus has shifted exclusively to mobile colistin resistances (mcr). This review will advance the understanding of chromosomal-mediated resistance mechanisms in Enterobacterales. We provide an overview about genes involved in colistin resistance and the current global situation of colistin-resistant Enterobacterales. A comparison of the global colistin use in veterinary and human medicine highlights the effort to reduce colistin sales in veterinary medicine under the One Health approach. In contrast, it uncovers the alarming rise in colistin consumption in human medicine due to the emergence of MDR Enterobacterales, which might be an important driver for the increasing emergence of chromosome-mediated colistin resistance.

Curcumin-meropenem synergy in carbapenem resistant Klebsiella pneumoniae curcumin-meropenem synergy

Background and Objectives:

The frequency of multiple resistant bacterial infections, including carbapenems, is increasing worldwide. As the decrease in treatment options causes difficulties in treatment, interest in new antimicrobials is increasing. One of the promising natural ingredients is curcumin. It is known to be effective in bacteria such as Pseudomonas aeruginosa, Escherichia coli, Burkholderia pseudomallei through efflux pump inhibition, toxin inhibition and enzymes. However, because its bioavailability is poor, it seffectiveness occurs in combination with antibiotics. In the study, the interaction of meropenem and curcumin in carbapenemase producing strains of Klebsiella pneumoniae was tested.

Materials and Methods:

Thirty-nine Klebsiella pneumoniae isolates, resistant to meropenem, were used in this study. From those 15 MBL, 6 KPC, 17 OXA-48 and 1 AmpC resistance pattern were detected by combination disk method. Meropenem and Curcumin MIC values were determined by liquid microdilution. Checkerboard liquid microdilution was used to determine the synergy between meropenem and curcumin.

Results:

Synergistic effects were observed in 4 isolates producing MBL, 3 isolates producing KPC, 4 isolates producing OXA-48, and 1 isolates producing AmpC (totally 12 isolates) according to the calculated FICI. No antagonistic effects were observed in any isolates.

Conclusion:

Curcumin was thought to be an alternative antimicrobial in combination therapies that would positively contribute to the treatment of bacterial infection. The effectiveness of this combination should be confirmed by other in vitro and clinical studies.

Molecular Mechanisms and Epidemiology of Carbapenem-Resistant Enterobacter cloacae Complex Isolated from Chinese Patients During 2004-2018

Background

The emergence and spread of carbapenem-resistant Enterobacter cloacae complex (ECC) have posed a serious threat to human health worldwide. This study aimed to investigate the molecular mechanism of carbapenem resistance and its prevalence among ECC in China.

Methods

A total of 1314 ECC clinical isolates were collected from the First Affiliated Hospital of Wenzhou Medical University from 2004 to 2018. Sensitivity to antibiotics was determined using the agar dilution method. The production of carbapenemases and the prevalence of resistance-associated genes were investigated using PCR. The expression of outer membrane porin (OMP) genes (ompC/ompF) and cephalosporinase gene ampC was analyzed by quantitative real-time PCR. The effect of efflux pump mechanism on carbapenem resistance was tested. ECC was typed by multilocus sequence typing (MLST).

Results

In this study, 113 carbapenem-nonsusceptible ECC strains were identified. The prevalence rates of carbapenemase genes bla _KPC-2 and bla _NDM were 12.4% (14/113) and 17.7% (20/113), and that of the extended-spectrum β-lactamase (ESBL) genes bla _CTX-M, bla _TEM, and bla _SHV were 28.3% (32/113), 27.4% (31/113), and 14.2% (16/113), respectively. Among 67 carbapenem-nonsusceptible ECC isolates producing non-carbapenemase, low expression of ompC/ompF and overexpression of ampC were found in 46 and 40 strains, respectively. In addition, the carbapenem resistance was related to the overexpression of the efflux pump in the study. Finally, the 113 carbapenem-nonsusceptible ECC strains were categorized into 39 different sequence types using MLST.

Conclusion

Carbapenem-nonsusceptible ECC strains producing non-carbapenemase were predominant. The low expression of OMP with the overexpression of cephalosporinase or production of ESBLs and overexpression of efflux pump might contribute to the resistance to carbapenem for carbapenem-nonsusceptible ECC strains producing non-carbapenemase. The bla _NDM and bla _KPC comprised the principal resistance mechanism of carbapenemase-producing ECC in the hospital, causing a threat to public health. Therefore, monitoring programs to prevent the emergence and further spread of antibiotic resistance are urgently needed.