In vitro activity of ceftazidime-avibactam, ceftolozane-tazobactam, and other comparable agents against clinically important Gram-negative bacilli: results from the 2017 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

Ceftolozane/tazobactam: Literature review of its activity on Taiwanese isolates before its launch in Taiwan (2012-2021)

Ceftolozane, a novel cephalosporin, combined with tazobactam, a known β-lactamase inhibitor, shows robust antipseudomonal activity, although it doesn't cover carbapenemases. Our review of data from 2012 to 2021 in Taiwan highlights TOL/TAZ's in-vitro performance. TOL/TAZ is most effective against Pseudomonas aeruginosa (91.3-94.4 % susceptible, with an MIC <4 μg/mL). It also demonstrates good activity against Enterobacterales, including Escherichia coli (88-94.3 % susceptible), Klebsiella pneumoniae (72.6-84.1 % susceptible), Citrobacter koseri (93.3 % susceptible), Klebsiella oxytoca (98.1-100 % susceptible), and Proteus mirabilis (100 % susceptible). However, its efficacy varies among species typically associated with chromosomally-mediated AmpC production, such as Morganella morganii (100 % susceptible), Serratia marcescens (81.3-90.0 % susceptible), Enterobacter cloacae species complex (76.6-76.7 % susceptible), Klebsiella aerogenes (66.7-89.6% susceptible), and Citrobacter freundii (60.0 % susceptible). For carbapenem-nonsusceptible isolates, TOL/TAZ is less effective against K. pneumoniae and E. coli (susceptibility <10 %) but remains useful for P. aeruginosa (susceptibility 81.3-91.8 %). In conclusion, TOL/TAZ shows potent activity against P. aeruginosa and carbapenem-susceptible Enterobacterales in Taiwan.

Penicillin-Binding Protein Occupancy Dataset for 18 β-Lactams and 4 β-Lactamase Inhibitors in Neisseria gonorrhoeae

The lack of effective first-line antibiotic treatments against Neisseria gonorrhoeae, and the worldwide dissemination of resistant strains, are the main drivers of a worsening global health crisis. β-lactam antibiotics have been the backbone of therapeutic armamentarium against gonococci. However, we are lacking critical insights to design rationally optimized therapies. In the present work, we generated the first PBP-binding data set on 18 currently available and clinically relevant β-lactams and 4 β-lactamase inhibitors in two N. gonorrhoeae ATCC type collection strains, 19424 and 49226 (PBP2 type XXII and A39T change in mtrR). PBP binding (IC50) was determined via the Bocillin FL binding assay in isolated membrane preparations. Three clusters of differential PBP IC50s were identified and were mostly consistent across both strains, but with quantitative differences. Carbapenems were coselective for PBP2 and PBP3 (0.01 to 0.03 mg/L). Third- and fourth-generation cephalosporins cefixime, cefotaxime, ceftazidime, cefepime, and ceftriaxone showed the lowest IC50 values for PBP2 (0.01 mg/L), whereas cefoxitin, ceftaroline, and ceftolozane required higher concentrations (0.04 to >2 mg/L). Aztreonam was selective for PBP2 in both strains (0.03 to 0.07 mg/L); amdinocillin bound this PBP at higher concentrations (1.33 to 2.94 mg/L). Penicillins specifically targeted PBP2 in strain ATCC 19424 (0.02 to 0.19 mg/L) and showed limited inhibition in strain ATCC 49226 (0.01 to >2 mg/L). Preferential PBP2 binding was observed by β-lactam-based β-lactamase inhibitors sulbactam and tazobactam (1.07 to 6.02 mg/L); meanwhile, diazabicyclooctane inhibitors relebactam and avibactam were selective for PBP3 (1.27 to 5.40 mg/L). This data set will set the bar for future studies that will help the rational use and translational development of antibiotics against multidrug-resistant (MDR) N. gonorrhoeae. IMPORTANCE The manuscript represents the first N. gonorrhoeae PBP-binding data set for 22 chemically different drugs in two type strains with different genetic background. We have identified three clusters of drugs according to their PBP binding IC50s and highlighted the binding differences across the two strains studied. With the currently available genomic information and the PBP-binding data, we have been able to correlate the target attainment differences and the mutations that affect the drug uptake with the MIC changes. The results of the current work will allow us to develop molecular tools of great practical use for the study and the design of new rationally designed therapies capable of combating the growing MDR gonococci threat.

Direct prediction of carbapenem-resistant, carbapenemase-producing, and colistin-resistant Klebsiella pneumoniae isolates from routine MALDI-TOF mass spectra using machine learning and outcome evaluation

The objective of this study was to develop a rapid prediction method for carbapenem-resistant Klebsiella pneumoniae (CRKP) and colistin-resistant K. pneumoniae (ColRKP) based on routine MALDI-TOF mass spectrometry (MS) results in order to formulate a suitable and rapid treatment strategy. In total, 830 CRKP and 1,462 carbapenem-susceptible K. pneumoniae (CSKP) isolates were collected; 54 ColRKP isolates and 1,592 colistin-intermediate K. pneumoniae (ColIKP) isolates were also included. Routine MALDI-TOF MS, antimicrobial susceptibility testing, NG-Test CARBA 5, and resistance gene detection were followed by machine learning (ML). Using the ML model, the accuracy and area under the curve for differentiating CRKP and CSKP were 0.8869 and 0.9551, and those for ColRKP and ColIKP were 0.8361 and 0.8447, respectively. The most important MS features of CRKP and ColRKP were m/z 4520-4529 and m/z 4170-4179, respectively. Of the CRKP isolates, MS m/z 4520-4529 was a potential biomarker for distinguishing KPC from OXA, NDM, IMP, and VIM. Of the 34 patients who received preliminary CRKP ML prediction results (by texting), 24 (70.6%) were confirmed to have CRKP infection. The mortality rate was lower in patients who received antibiotic regimen adjustment based on the preliminary ML prediction (4/14, 28.6%). In conclusion, the proposed model can provide rapid results for differentiating CRKP and CSKP, as well as ColRKP and ColIKP. The combination of ML-based CRKP with preliminary reporting of results can help physicians alter the regimen approximately 24 h earlier, resulting in improved survival of patients with timely antibiotic intervention.

Off-label use versus formal recommendations of conventional and novel antibiotics for the treatment of infections caused by multidrug-resistant bacteria

The infections caused by multidrug- and extensively drug-resistant (MDR, XDR) bacteria, including Gram-positive cocci (GPC, including methicillin-resistant Staphylococcus aureus, MDR-Streptococcus pneumoniae and vancomycin-resistant enterococci) and Gram-negative bacilli (GNB, including carbapenem-resistant [CR] Enterobacterales, CR-Pseudomonas aeruginosa and XDR/CR-Acinetobacter baumannii complex) can be quite challenging for physicians with respect to treatment decisions. Apart from complicated urinary tract and intra-abdominal infections (cUTIs, cIAIs), bloodstream infections and pneumonia, these difficult-to-treat bacteria also cause infections at miscellaneous sites (bones, joints, native/prosthetic valves and skin structures, etc.). Antibiotics like dalbavancin, oritavancin, telavancin and daptomycin are currently approved for the treatment of acute bacterial skin and skin structural infections (ABSSSIs) caused by GPC. Additionally, ceftaroline, linezolid and tigecycline have been formally approved for the treatment of community-acquired pneumonia and ABSSSI. Cefiderocol and meropenem-vaborbactam are currently approved for the treatment of cUTIs caused by XDR-GNB. The spectra of ceftazidime-avibactam and imipenem/cilastatin-relebactam are broader than that of ceftolozane-tazobactam, but these three antibiotics are currently approved for the treatment of hospital-acquired pneumonia, cIAIs and cUTIs caused by MDR-GNB. Clinical investigations of other novel antibiotics (including cefepime-zidebactam, aztreonam-avibactam and sulbactam-durlobactam) for the treatment of various infections are ongoing. Nevertheless, evidence for adequate antibiotic regimens against osteomyelitis, arthritis and infective endocarditis due to several GPC and MDR-GNB is still mostly lacking. A comprehensive review of PubMed publications was undertaken and the formal indications and off-label use of important conventional and novel antibiotics against MDR/XDR-GPC and GNB isolates cultured from miscellaneous sites are presented in this paper.

Global status of Azithromycin and Erythromycin Resistance Rates in Neisseria gonorrhoeae: A Systematic Review and Meta-analysis

Background: The widespread development of antibiotic resistance or decreased susceptibility in Neisseria gonorrhoeae (NG) infection is a global and significant human public health issue. Objectives: Therefore, this meta-analysis aimed to estimate worldwide resistance rates of NG to the azithromycin and erythromycin according to years, regions, and antimicrobial susceptibility testing (AST). Methods: We systematically searched the published studies in PubMed, Scopus, and Embase from 1988 to 2021. All analyses were conducted using Stata software. Results: The 134 reports included in the meta-analysis were performed in 51 countries and examined 165,172 NG isolates. Most of the included studies were from Asia (50 studies) and Europe (46 studies). In the metadata, the global prevalence over the past 30 years were 6% for azithromycin and 48% for erythromycin. There was substantial change in the prevalence of macrolides NG resistance over time (P <0.01). In this metadata, among 58 countries reporting resistance data for azithromycin, 17 (29.3%) countries reported that >5% of specimens had azithromycin resistance. Conclusions: The implications of this study emphasize the rigorous or improved antimicrobial stewardship, early diagnosis, contact tracing, and enhanced intensive global surveillance system are crucial for control of further spreading of gonococcal emergence of antimicrobial resistance (AMR).

Prevalence of Multidrug-Resistant and Extended-Spectrum Beta-Lactamase-Producing Shigella Species in Asia: A Systematic Review and Meta-Analysis

Shigellosis remains one of the leading causes of morbidity and mortality worldwide and is the second leading cause of diarrheal mortality among all age groups. However, the global emergence of antimicrobial-resistant Shigella strains, limiting the choice of effective drugs for shigellosis, has become the major challenge in the treatment of Shigella infections. The aim of this systematic review and meta-analysis was to provide an updated picture of the prevalence of antimicrobial-resistant Shigella species in Asia. A comprehensive and systematic search was performed on three electronic databases (PubMed, ScienceDirect and Scopus), in which 63 eligible studies published between 2010 and 2022 were identified. From our meta-analysis of proportions using a random-effects model, the overall prevalence of Shigella spp. in Asian patients was estimated to be 8.0% (95% CI: 5.5–10.5). The pooled prevalence rates of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing Shigella strains were 68.7% (95% CI: 59.9–77.5) and 23.9% (95% CI: 12.9–34.8), respectively. Concerning recommended antimicrobial drugs for Shigella, the prevalence of resistance was highest for ciprofloxacin (29.8%) and azithromycin (29.2%), followed by ceftriaxone (23.8%), in spite of their importance as first- and second-line treatments for shigellosis. In contrast, resistance to carbapenems, such as ertapenem (0.0%), imipenem (0.1%) and meropenem (0.0%), was almost non-existent among the 49 tested antibiotics. The significantly high prevalence estimation suggests that the multidrug-resistant Shigella is a pressing threat to public health worthy of careful and justified interventions. Effective antibiotic treatment strategies, which may lead to better outcomes for the control and treatment of shigellosis in Asia, are essential.

Multicenter Surveillance of Capsular Serotypes, Virulence Genes, and Antimicrobial Susceptibilities of Klebsiella pneumoniae Causing Bacteremia in Taiwan, 2017–2019

We conducted a longitudinal epidemiological surveillance of hypervirulent Klebsiella pneumoniae (hvKP) in Taiwan. Bacteremic KP isolates collected from 16 hospitals in Taiwan between 2017 and 2019 were collected, and the virulent serotypes (K1, K2, K20, K54, and K57), antimicrobial susceptibilities, and virulence genes of these isolates were investigated. During the 3-year period, 1,310 bacteremic KP isolates were collected, of which 27.5% belonged to virulent serotypes, including K1 (n = 162), K2 (n = 74), K57 (n = 56), K54 (n = 41), and K20 (n = 27). K1 was the most prevalent capsular serotype, with an annual prevalence of 11–15%, and was equally distributed across the four geographic areas. The prevalence of K2 declined significantly in 2019. According to wzi-K typing results, 87% of K1 isolates were classified as wzi-1. Among K2 isolates, wzi-72 (55.4%) and wzi-2 (41.9%) were the most common, whereas wzi-206 was the most prevalent (48.2%) among K57 isolates, followed by wzi-77 (25.0%). Wzi-115 accounted for 85.4% of the K54 isolates, whereas wzi-95 accounted for 92.6% of K20 isolates. rmpA was present in 99.4% of K1, 98.6% of K2, 89.3% of K57, 78.0% of K54, and 84.0% of K20 isolates. rmpA2 was present in 100% of K1 and 98.6% of K2 isolates but was only present in 64.3% of K57, 58.5% of K54, and 74.1% of K20 isolates. K1 remains the dominant hvKP serotype and is associated with most virulence genes in Taiwan. Further studies are required to elucidate the significance of other virulent serotypes.

Global Threat of Carbapenem-Resistant Gram-Negative Bacteria

Infections caused by multidrug-resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria (GNB), including carbapenem-resistant (CR) Enterobacterales (CRE; harboring mainly bla_KPC, bla_NDM, and bla_OXA-48-like genes), CR- or MDR/XDR-Pseudomonas aeruginosa (production of VIM, IMP, or NDM carbapenemases combined with porin alteration), and Acinetobacter baumannii complex (producing mainly OXA-23, OXA-58-like carbapenemases), have gradually worsened and become a major challenge to public health because of limited antibiotic choice and high case-fatality rates. Diverse MDR/XDR-GNB isolates have been predominantly cultured from inpatients and hospital equipment/settings, but CRE has also been identified in community settings and long-term care facilities. Several CRE outbreaks cost hospitals and healthcare institutions huge economic burdens for disinfection and containment of their disseminations. Parenteral polymyxin B/E has been observed to have a poor pharmacokinetic profile for the treatment of CR- and XDR-GNB. It has been determined that tigecycline is suitable for the treatment of bloodstream infections owing to GNB, with a minimum inhibitory concentration of ≤ 0.5 mg/L. Ceftazidime-avibactam is a last-resort antibiotic against GNB of Ambler class A/C/D enzyme-producers and a majority of CR-P. aeruginosa isolates. Furthermore, ceftolozane-tazobactam is shown to exhibit excellent in vitro activity against CR- and XDR-P. aeruginosa isolates. Several pharmaceuticals have devoted to exploring novel antibiotics to combat these troublesome XDR-GNBs. Nevertheless, only few antibiotics are shown to be effective in vitro against CR/XDR-A. baumannii complex isolates. In this era of antibiotic pipelines, strict implementation of antibiotic stewardship is as important as in-time isolation cohorts in limiting the spread of CR/XDR-GNB and alleviating the worsening trends of resistance.

Multicenter surveillance of in vitro activities of cefepime-zidebactam, cefepime-enmetazobactam, omadacycline, eravacycline, and comparator antibiotics against Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii complex causing bloodstream infection in Taiwan, 2020

OBJECTIVES

: To determine the in vitro activities of novel and comparator antibiotics against gram-negative bacteria (GNB) in Taiwan.

METHODS

: Isolates of Escherichia coli (n = 335), Klebsiella pneumoniae (n = 316; 144 isolates with hyperviscosity characteristics), Pseudomonas aeruginosa (n = 271), Acinetobacter baumannii complex species (n = 187), and non-typhoidal Salmonella species (n = 226), Shigella species (n = 13) from miscellaneous culture sources were collected in 2020 in Taiwan. The MICs of the isolates to test antibiotics were determined using the broth microdilution method. GeneXpert was used to detect genes encoding carbapenemases among the carbapenem-non-susceptible (NS) Enterobacterales isolates.

RESULTS

: The MIC values of the cefepime-enmetazobactam combination against extended-spectrum β-lactamase-producing E. coli and K. pneumoniae isolates (MIC₉₀ ≤ 0.5 mg/L), bla_KPC-harboring E. coli isolates (0.25 mg/L; n = 2), and 80% of bla_OXA-48-like gene-harboring K. pneumoniae isolates (≤2 mg/L) were low. The MIC ranges of the cefepime-zidebactam against carbapenemase-producing Enterobacterales isolates (irrespective of the carbapenemase type [MIC₉₀ ≤ 4 mg/L]) and carbapenem-NS or ceftolozane-tazobactam-NS P. aeruginosa isolates (MIC₉₀ value, 8 mg/L) were significantly lower than those of the cefepime-enmetazobactam.

CONCLUSIONS

: The efficacy of novel antibiotics against important drug-resistant GNB must be monitored and validated during the clinical treatment of patients.

Global Prevalence and Molecular Epidemiology of mcr-Mediated Colistin Resistance in Escherichia coli Clinical Isolates: A Systematic Review

BACKGROUND AND AIM

The continuing rise in infections caused by multi-drug resistant (MDR) bacteria is one of the most serious public health issues in today's societies. Colistin is a last-resort antimicrobial medication used to treat infections caused by MDR gram-negative bacteria; therefore resistance to this antibiotic is extremely hazardous. The current study aimed to evaluate the global prevalence and distribution of colistin resistance genes among human clinical isolates of Escherichia coli (E. coli) as a systematic review.

METHODS

PubMed, Embase, and Web of Science databases were systematically searched. For further evaluation, all original English-language articles that demonstrated colistin resistance in E. coli clinical isolates published between 2000 and 2020 were examined.

RESULTS

Out of 4857 initial articles, after various stages of review and evaluation, 190 related articles were selected. More than 79 % of the publications selected in this research were published from 2014 to 2020. In Asia, Europe, America, Africa, and Oceania, the prevalence of mobilized colistin resistance (mcr) producing colistin-resistant E. coli was 66.72%, 25.48%, 5.19%, 2.27%, and 0.32 %, respectively.

CONCLUSION

The recent widespread spreading of E. coli strains harboring mcr conferring colistin resistance, especially in Asia and Europe, is concerning and needs more attention.

Ceftazidime-avibactam: are we safe from class A carbapenemase producers' infections?

Recently, new combinations of β-lactams and β-lactamase inhibitors became available, including ceftazidime-avibactam, and increased the ability to treat infections caused by carbapenem-resistant Enterobacterales (CRE). Despite the reduced time of clinical use, isolates expressing resistance to ceftazidime-avibactam have been reported, even during treatment or in patients with no previous contact with this drug. Here, we detailed review data on global ceftazidime-avibactam susceptibility, the mechanisms involved in resistance, and the molecular epidemiology of resistant isolates. Ceftazidime-avibactam susceptibility remains high (≥ 98.4%) among Enterobacterales worldwide, being lower among extended-spectrum β-lactamase (ESBL) producers and CRE. Alterations in class A β-lactamases are the major mechanism involved in ceftazidime-avibactam resistance, and mutations are mainly, but not exclusively, located in the Ω loop of these enzymes. Modifications in Klebsiella pneumoniae carbapenemase (KPC) 3 and KPC-2 have been observed by many authors, generating variants with different mutations, insertions, and/or deletions. Among these, the most commonly described is Asp179Tyr, both in KPC-3 (KPC-31 variant) and in KPC-2 (KPC-33 variant). Changes in membrane permeability and overexpression of efflux systems may also be associated with ceftazidime-avibactam resistance. Although several clones have been reported, ST258 with Asp179Tyr deserves special attention. Surveillance studies and rationale use are essential to retaining the activity of this and other antimicrobials against class A CRE.

The safety of ceftolozane-tazobactam for the treatment of acute bacterial infections: a systemic review and meta-analysis

Objectives

The aim of this study was to conduct a meta-analysis to assess the clinical safety of ceftolozane-tazobactam for the treatment of acute bacterial infections in adult patients.

Methods

The PubMed, Embase, and Cochrane databases were searched from their inception until May 2020 for relevant randomized controlled trials (RCTs). Only RCTs evaluating the risk of adverse events (AEs) for ceftolozane-tazobactam and comparative treatments for acute bacterial infections in adult patients were included.

Results

Overall, four RCTs including a total of 2924 patients (1475 in the ceftolozane-tazobactam group and 1449 in the control group) were included in the meta-analysis. The rate of treatment-emergent AEs was 51.3% (748/1458) in the ceftolozane-tazobactam group, which was comparable to the control group, 49.9% [714/1430; odd's ratio (OR), 1.06; 95% confidence interval (CI), 0.91-1.25; I ² = 0%]. In addition, no difference was observed between the ceftolozane-tazobactam and control groups in terms of the risk of serious AEs (OR, 1.22; 95% CI, 0.93-1.61; I ² = 15.5%) and the risk of discontinuing the study drug due to AEs (OR, 0.85; 95% CI, 0.55-1.33; I ² = 0%). The rate of all-cause mortality did not significantly differ between the ceftolozane-tazobactam and control groups (OR, 1.11; 95% CI, 0.82-1.50; I ² = 0%). The only exception was the risk of Clostridiodes difficile (C. difficile) colitis, where ceftolozane-tazobactam treatment was associated with a significantly higher risk compared with the control group [0.72% (10/1376) versus 0.14% (2/1391), OR, 3.84; 95% CI, 1.23-11.97; I ² = 0%].

Conclusion

Ceftolozane-tazobactam treatment is as tolerable as comparative treatment options for acute bacterial infections in adult patients, however it has an increased risk of C. difficile infection. As a novel broad-spectrum antibiotic, ceftolozane-tazobactam could be a safe therapeutic option for use in common clinical practice.

Plain language summary

The safety of ceftolozane-tazobactam (an antibiotics) for the treatment of acute bacterial infections Objective(s): Ceftolozane-tazobactam is an effective antibiotic for the treatment of acute bacterial infections. This study conducts a meta-analysis to assess the clinical safety (side effects) of ceftolozane-tazobactam for the treatment of acute bacterial infections in adult patients compared with other drugs. Methods: We extracted data from four randomized controlled trials, including a total of 2924 patients (1475 in the ceftolozane-tazobactam group and 1449 in the control group). Results: The rate of treatment related adverse events (AEs) was similar in the ceftolozane-tazobactam group (51.3%) and control group (49.9%). There was also no difference in risk of serious adverse events, the risk of discontinuing the study drug due to AEs, and all-cause mortality. The only exception was the risk of Clostridiodes difficile colitis (a cause of antibiotic-associated diarrhea), where ceftolozane-tazobactam treatment was associated with a significantly higher risk compared with the control group. Conclusion: In conclusion, as a novel broad-spectrum antibiotic, ceftolozane-tazobactam could be a safe therapeutic option for use in clinical practice.

Antimicrobial activity of ceftolozane-tazobactam against Enterobacterales and Pseudomonas aeruginosa recovered during the Study for Monitoring Antimicrobial Resistance Trends (SMART) program in Spain (2016-2018)

OBJECTIVE

To analyse the susceptibility to ceftolozane-tazobactam and comparators in Enterobacterales and Pseudomonas aeruginosa isolates recovered from intraabdominal (IAI), urinary (UTI), respiratory (RTI) and bloodstream infection (BSI) in the SMART (Study for Monitoring Antimicrobial Resistance Trends) study.

METHODS

The susceptibility of 5,351 isolates collected in 11 Spanish hospitals (2016-2018) were analysed (EUCAST-2020 criteria) by broth microdilution and were phenotypically studied for the presence of extended-spectrum beta-lactamases (ESBL). Ceftolozane-tazobactam and/or carbapenem resistant isolates were genetically characterized for ESBL and carbapenemases.

RESULTS

Escherichia coli was the most frequent pathogen (49.3% IAI, 54.9% UTI, 16.7% RTI and 50% BSI), followed by Klebsiella pneumoniae (11.9%, 19.1%, 13.1% and 15.4%, respectively). P. aeruginosa was isolated in 9.3%, 5.6%, 32% and 9%, respectively. The frequency of isolates with ESBLs (2016-2017) was: 30.5% K. pneumoniae, 8.6% E. coli, 2.3% Klebsiella oxytoca and 0.7% Proteus mirabilis. Ceftolozane-tazobactam was very active against non-ESBL-(99.3% susceptible) and ESBL-(95.2%) producing E. coli being less active against K. pneumoniae (98% and 43.1%, respectively) isolates. CTX-M-15 was the most prevalent ESBL in E. coli (27.5%) and K. pneumoniae (51.9%) frequently associated with OXA-48-like carbapenemase. Overall, 93% of P. aeruginosa isolates were susceptible to ceftolozane-tazobactam, preserving this activity (>75%) in isolates resistant to other beta-lactams except in those resistant to meropenen or ceftazidime-avibactam. GES-5, PER-1, VIM-1/2 were the most prevalent enzymes in isolates resistant to ceftolozane-tazobactam.

CONCLUSIONS

Ceftolozane-tazobactam showed high activity rates against isolates recovered in the SMART study although it was affected in K. pneumoniae and P. aeruginosa isolates with ESBL and/or carbapenemases.

Klebsiella pneumoniae Harboring Carbapenemase Genes in Taiwan: Its Evolution over 20 Years, 1998-2019

Klebsiella pneumoniae (K. pneumoniae) is an important pathogen causing various types of human infections in Taiwan. Carbapenemases have increasingly been reported in Enterobacterales in the past two decades. Carbapenemase-producing K. pneumoniae (CPKP), a major resistance concern that has emerged during the last decade, has become a global threat, with its related infections associated with high morbidity and mortality; however, therapeutic options for CPKP-associated infections are limited. Carbapenemases - including K. pneumoniae carbapenemases (KPC)-2, New Delhi metallo-β-lactamase (NDM)-1, Verona integron-encoded metallo-β-lactamase (VIM)-1, imipenemase (IMP)-1, and oxacillinase (OXA)-48 - have been reported worldwide, with a marked prevalence in different countries or areas of the world. Understanding the epidemiology of carbapenemase producers is important for the prevention of their expansion. This review examined the evolution of CPKP in the last two decades to better understand the role of CPKP in Taiwan. It discovered that the endemicity has changed from IMP-8, NDM-1 and VIM-1 to the most common KPC-2 and rapidly emerging OXA-48. Resistance epidemiology, genetic background, virulence factors, therapy, and outcomes are discussed in this paper.

A Large Spatial Survey of Colistin-Resistant Gene mcr-1-Carrying E. coli in Rivers across Taiwan

BACKGROUND

Colistin is one of the last-line antimicrobial agents against life-threatening infections. The distribution of the colistin resistance gene mcr-1 has been reported worldwide. However, most studies have focused on the distribution of mcr-1-positive bacteria in humans, animals, food, and sewage; few have focused on their distribution in natural environments.

METHOD

We conducted a large spatial survey of mcr-1-positive Escherichia coli at 119 sites in 48 rivers, covering the entire island of Taiwan. We investigated the relationship between the livestock or poultry density in the surveyed riverine area and the number of mcr-1-positive E. coli in the river water. We then sequenced and characterized the isolated mcr-1-positive plasmids.

RESULTS

Seven mcr-1 positive E. coli were isolated from 5.9% of the sampling sites. The mcr-1-positive sites correlated with high chicken and pig stocking densities but not human population density or other river parameters. Four of the mcr-1-positive E. coli strains harbored epidemic IncX4 plasmids, and three of them exhibited identical sequences with a size of 33,309 bp. One of the plasmids contained identical 33,309 bp sequences but carried an additional 5711-bp transposon (Tn3 family). To our knowledge, this is the first demonstration that mcr-1-carrying IncX4 plasmids can contain an insertion of such transposons. All mcr-1-positive isolates belonged to phylogenetic group A and harbored few known virulence genes.

CONCLUSION

This study showed a positive relationship between the number of mcr-1-positive sites and high livestock and poultry density. The sequencing analyses indicated that the epidemic plasmid in the mcr-1 isolates circulates not only in humans, animals, and food but also in the associated environments or natural habitats in Taiwan, suggesting that the surveillance of antibiotics-resistance genes for livestock or poultry farm quality control should include their associated environments.

Activities of imipenem-relebactam combination against carbapenem-nonsusceptible Enterobacteriaceae in Taiwan

BACKGROUND

Imipenem-relebactam is a new β-lactam and β-lactamase inhibitor combination to treat carbapenem-resistant gram-negative bacteria infections. However, difference in carbapenem resistant mechanisms existed with geographic variations.

OBJECTIVE

To evaluate the susceptibility of imipenem-relebactam to 660 carbapenem-nonsusceptible Enterobacteriaceae isolates in Taiwan and to identify the in vivo efficacy with a Caenorhabditis elegans model.

METHODS

188 carbapenem-nonsusceptible Escherichia coli isolates and 472 carbapenem-nonsusceptible Klebsiella pneumoniae isolates were collected from a national surveillance study in Taiwan. The antimicrobial susceptibility profiles and carbapenemase distributions were determined. An agar dilution method was performed to evaluate the in vitro activities of imipenem monotherapy and imipenem-relebactam combination. Contributions of metallo-carbapenemase to imipenem-relebactam susceptibility was investigated via EDTA treatment. A C. elegans model was used to evaluate the in vivo efficacy of imipenem-relebactam combination.

RESULTS

87.8% and 82.2% susceptibility to imipenem-relebactam was observed for 188 carbapenem-nonsusceptible E. coli and 472 carbapenem-nonsusceptible K. pneumoniae, respectively. However, poor activities of imipenem-relebactam was observed against 23 metallo-carbapenemase producers tested in this study. In the in vivo C. elegans model, imipenem-relebactam significantly rescued nematodes from the infection of a bla_KPC-producing K. pneumoniae isolate.

CONCLUSION

Our study supports that imipenem-relebactam is a potential therapy against carbapenem-nonsusceptible Enterobacteriaceae, and to our knowledge, this is the first report of evaluation for imipenem-relebactam efficacy against carbapenem-nonsusceptible Enterobacteriaceae in Taiwan.

Increasing New Delhi metallo-β-lactamase-positive Escherichia coli among carbapenem non-susceptible Enterobacteriaceae in Taiwan during 2016 to 2018

New Delhi metallo-β-lactamase (NDM) had been reported to be the predominant carbapenemase among Escherichia coli in Taiwan. However, studies focusing on the clonal background and epidemiology of plasmids carrying NDM genes were limited. Between 2016 and 2018, all clinical E. coli and Klebsiella pneumoniae isolates that were non-susceptible to ertapenem, meropenem, and imipenem were tested for carbapenemase-encoding genes (CEGs) and antimicrobial susceptibilities. Molecular typing was performed on all carbapenemase-producing isolates. Whole genome sequencing (WGS) was performed on all NDM-positive E. coli isolates. Twenty-three (29.5%) of 78 carbapenem non-susceptible E. coli and 108 (35.3%) of 306 carbapenem non-susceptible K. pneumoniae isolates carried CEGs. The most prevalent CEGs in carbapenemase-producing E. coli (CPEc) were blaNDM (39.1%) and blaIMP-8 (30.4%), while that in carbapenemase-producing K. pneumoniae was Klebsiella pneumoniae carbapenemase (KPC) (72.2%). Fifteen sequence types were identified among 23 CPEc, and 55.6% of NDM-positive E. coli isolates belonged to ST410. WGS showed ST410 isolates were highly clonal and similar to those from other countries. All NDM-5-positive E. coli isolates carried identical IncX3 plasmid harboring blaNDM-5 but no other antimicrobial resistance (AMR) genes. In each of the four NDM-1-positive E. coli isolates, the blaNDM-1 was present in a ∼ 300 kb IncHI2/IncHI2A plasmid which carried an array of AMR genes. NDMs are the most prevalent carbapenemase among CPEc in Taiwan. Awareness should be raised as the prevalence of NDM-positive E. coli might increase rapidly with IncX3 plasmid and globally distributed strain ST410 being the potential vectors for wide dissemination.

New β-Lactam-β-Lactamase Inhibitor Combinations

The limited armamentarium against drug-resistant Gram-negative bacilli has led to the development of several novel β-lactam-β-lactamase inhibitor combinations (BLBLIs). In this review, we summarize their spectrum of in vitro activities, mechanisms of resistance, and pharmacokinetic-pharmacodynamic (PK-PD) characteristics. A summary of available clinical data is provided per drug. Four approved BLBLIs are discussed in detail. All are options for treating multidrug-resistant (MDR) Enterobacterales and Pseudomonas aeruginosa Ceftazidime-avibactam is a potential drug for treating Enterobacterales producing extended-spectrum β-lactamase (ESBL), Klebsiella pneumoniae carbapenemase (KPC), AmpC, and some class D β-lactamases (OXA-48) in addition to carbapenem-resistant Pseudomonas aeruginosa Ceftolozane-tazobactam is a treatment option mainly for carbapenem-resistant P. aeruginosa (non-carbapenemase producing), with some activity against ESBL-producing Enterobacterales Meropenem-vaborbactam has emerged as treatment option for Enterobacterales producing ESBL, KPC, or AmpC, with similar activity as meropenem against P. aeruginosa Imipenem-relebactam has documented activity against Enterobacterales producing ESBL, KPC, and AmpC, with the combination having some additional activity against P. aeruginosa relative to imipenem. None of these drugs present in vitro activity against Enterobacterales or P. aeruginosa producing metallo-β-lactamase (MBL) or against carbapenemase-producing Acinetobacter baumannii Clinical data regarding the use of these drugs to treat MDR bacteria are limited and rely mostly on nonrandomized studies. An overview on eight BLBLIs in development is also provided. These drugs provide various levels of in vitro coverage of carbapenem-resistant Enterobacterales, with several drugs presenting in vitro activity against MBLs (cefepime-zidebactam, aztreonam-avibactam, meropenem-nacubactam, and cefepime-taniborbactam). Among these drugs, some also present in vitro activity against carbapenem-resistant P. aeruginosa (cefepime-zidebactam and cefepime-taniborbactam) and A. baumannii (cefepime-zidebactam and sulbactam-durlobactam).

In Vitro and In Vivo Evaluations of β-Lactam/β-Lactamase Mono- and Combined Therapies against Carbapenem-Nonsusceptible Enterobacteriaceae in Taiwan

Increasing carbapenem resistance rates worldwide underscored the urgent need of novel antimicrobials. Ceftazidime–avibactam and aztreonam–avibactam combinations are developed to combat carbapenem resistance, but biological and geographic variations must be considered for antibiotic susceptibility patterns varied. Thus, we sought to assess the susceptibilities of ceftazidime–avibactam and aztreonam–avibactam against 660 carbapenem-nonsusceptible Enterobacteriaceae isolates (472 Klebsiella pneumoniae and 188 Escherichia coli) collected during an earlier Taiwan surveillance study. Agar dilution method was used to determine ceftazidime–avibactam and aztreonam–avibactam susceptibility. Metallo-carbapenemase’s contribution to resistance were investigated with EDTA addition. The in vivo efficacies were evaluated using a Caenorhabditis elegans model. High susceptibility rates were observed for ceftazidime–avibactam and aztreonam–avibactam against the 472 carbapenem-nonsusceptible K. pneumoniae (CnsKP) (85.2% and 95.3%, respectively) and 188 carbapenem-nonsusceptible E. coli (CnsEC) isolates (91.5% and 94.1%, respectively). For non-metallo-carbapenemase producers, the susceptibility rates for ceftazidime–avibactam were 93.6% for CnsKP and 97.7% for CnsEC, whereas only 7.1% CnsKP and 11.1% CnsEC in metallo-carbapenemase producers were susceptible to ceftazidime–avibactam. Of all isolates, 95.3% CnsKP and 94.1% CnsEC were susceptible to aztreonam–avibactam. In C. elegans model, ceftazidime–avibactam and aztreonam–avibactam revealed effective against a bla_KPC-producing K. pneumoniae isolate in vivo. Our results propose a positive therapeutic approach for both combinations against carbapenem-nonsusceptible Enterobacteriaceae in Taiwan.

National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored bla _KPC (n = 17), bla _OXA-48 (n = 2), and bla _VIM (n = 1) genes.

Characterization and Source Investigation of Multidrug-Resistant Salmonella Anatum from a Sustained Outbreak, Taiwan

An ongoing outbreak of multidrug-resistant Salmonella enterica serovar Anatum began in Taiwan in 2015. Pork and poultry were identified as vehicles for transmission. Contaminated meat contributed to the high rate of infections among children. Nearly identical Salmonella Anatum strains have been identified in the United Kingdom, the United States, and the Philippines.

Colistin-sparing approaches with newer antimicrobials to treat carbapenem-resistant organisms: Current evidence and future prospects

Antimicrobial resistance is on the rise across the globe. Increasing incidence of infections due to carbapenem resistance organisms is becoming difficult to treat, due to the limited availability of therapeutic agents. Very few agents such as colistin, fosfomycin, tigecycline and minocycline are widely used, despite its toxicity. However, with the availability of novel antimicrobials, beta-lactam/beta-lactamase inhibitor-based and non-beta-lactam-based agents could be of great relief. This review covers three important aspects which include (i) current management of carbapenem-resistant infections, (ii) determination of specific types of carbapenemases produced by multidrug-resistant and extensively drug-resistant Gram-negative pathogens and (iii) the currently available novel beta-lactam/beta-lactamase inhibitors and non-beta-lactam-based agents' laboratory findings, clinical outcome and implications.

Emergence and Evolution of High-Level Cephalosporin-Resistant Salmonella Goldcoast in Northern Taiwan

Background

Nontyphoidal Salmonella (NTS) is an important foodborne pathogen worldwide. We investigated a 2018 outbreak of highly antimicrobial-resistant Salmonella enterica serotype Goldcoast in northern Taiwan.

Methods

We collected 30 clinical isolates and 2 meat isolates from this outbreak in New Taipei and Taoyuan, Taiwan in 2018. The clinical manifestations and the treatment of the patients were reviewed. To trace the source, we examined NTS isolated from food samples collected from the markets in northern Taiwan. All of the isolates along with an additional human isolate from China were sequenced and compared with the sequences of Salmonella Goldcoast reported by other countries.

Results

The outbreak involved 14 pediatric patients (<5 years old) and 16 adults (36 to 83 years old). Nine patients with invasive or severe disease required carbapenem treatment. The MIC₉₀ of ceftriaxone and ciprofloxacin for the outbreak isolates was >256 μg/mL and 1 μg/mL, respectively, and a conjugative 278-kilobase plasmid harboring bla_CTX-M-55 and qnrS1 contributed towards the resistance. Whole-genome sequencing revealed a clonal relationship among the outbreak isolates and the 2 collected from the retail meats. The outbreak clone was phylogenetically close to that of Salmonella Goldcoast reported in the United Kingdom, Poland, and China, whereas similar resistance plasmids were found in China and Cambodia.

Conclusions

The clinical spectrum of the high-level cephalosporin-resistant Salmonella Goldcoast is similar to that of other NTS serotypes, but severe cases required carbapenem treatment. The study confirmed the emergence of a highly antimicrobial-resistant clone of Salmonella Goldcoast, highlighting the importance of surveillance for food safety.

The latest advances in β-lactam/β-lactamase inhibitor combinations for the treatment of Gram-negative bacterial infections

Introduction: Antimicrobial resistance in Gram-negative pathogens is a significant threat to global health. β-Lactams (BL) are one of the safest and most-prescribed classes of antibiotics on the market today. The acquisition of β-lactamases, especially those which hydrolyze carbapenems, is eroding the efficacy of BLs for the treatment of serious infections. During the past decade, significant advances were made in the development of novel BL-β-lactamase inhibitor (BLI) combinations to target β-lactamase-mediated resistant Gram-negatives.Areas covered: The latest progress in 20 different approved, developing, and preclinical BL-BLI combinations to target serine β-lactamases produced by Gram-negatives are reviewed based on primary literature, conference abstracts (when available), and US clinical trial searches within the last 5 years. The majority of the compounds that are discussed are being evaluated as part of a BL-BLI combination.Expert opinion: The current trajectory in BLI development is promising; however, a significant challenge resides in the selection of an appropriate BL partner as well as the development of resistance linked to the BL partner. In addition, dosing regimens for these BL-BLI combinations need to be critically evaluated. A revolution in bacterial diagnostics is essential to aid clinicians in the appropriate selection of novel BL-BLI combinations for the treatment of serious infections.

New Drugs for Multidrug-Resistant Gram-Negative Organisms: Time for Stewardship

A gradual rise in drug-resistant trends among Gram-negative organisms, especially carbapenem-resistant (CR) Enterobacteriaceae (CRE), CR-Pseudomonas aeruginosa, and extensively-drug-resistant (XDR) Acinetobacter baumannii, poses an enormous threat to healthcare systems worldwide. In the last decade, many pharmaceutical companies have devoted enormous resources to the development of new potent antibiotics against XDR Gram-negative pathogens, particularly CRE. Some of these novel antibiotics against CRE strains are β-lactam/β-lactamase-inhibitor combination agents, while others belong to the non-β-lactam class. Most of these antibiotics display good in vitro activity against the producers of Ambler class A, C, and D β-lactamase, although avibactam and vaborbactam are not active in vitro against metallo-β-lactamase (MβL) enzymes. Nevertheless, in vitro efficacy against the producers of some or all class B enzymes (New Delhi MβL, Verona integron-encoded MβL, etc) has been shown with cefepime-zidebactam, aztreonam-avibactam, VNRX-5133, cefiderocol, plazomicin, and eravacycline. As of Feburary 2019, drugs approved for treatment of some CRE-related infections by the US Food and Drug Administration included ceftazidime-avibactam, meropenem-vaborbactam, plazomicin, and eravacycline. Although active against extended-spectrum and AmpC β-lactamase-producing Enterobacteriaceae, delafloxacin does not show in vitro activity against CRE. Murepavadin is shown to be specifically active against CR- and colistin-resistant P. aeruginosa strains. Despite successful development of novel antibiotics, strict implementation of an antibiotic stewardship policy in combination with the use of well-established phenotypic tests and novel multiplex PCR methods for detection of the most commonly encountered β-lactamases/carbapenemases in hospitals is important for prescribing effective antibiotics against CRE and decreasing the resistance burden due to CRE.

Longitudinal analysis of the in vitro activity of ceftazidime/avibactam versus Enterobacteriaceae, 2012-2016

OBJECTIVES

The in vitro activities of ceftazidime/avibactam and comparator antimicrobial agents were analysed against 59 828 Enterobacteriaceae isolates collected by 190 centres from all global regions except North America from 2012-2016 as part of the International Network for Optimal Resistance Monitoring (INFORM) global surveillance programme.

METHODS

Antimicrobial susceptibility testing was performed using Clinical and Laboratory Standards Institute broth microdilution panels at a central reference laboratory, except for isolates collected in China that were tested using frozen, dehydrated broth microdilution panels at a central laboratory in China. The presence of extended-spectrum β-lactamases (ESBLs) was confirmed by multiplex PCR assays.

RESULTS

Ceftazidime/avibactam was the most active agent against all Enterobacteriaceae (MIC₉₀, ≤1mg/L, ≥98.4% susceptibility). High rates of susceptibility (>88%) were observed amongst Citrobacter freundii, Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca to colistin, meropenem, amikacin and tigecycline. Ceftazidime/avibactam showed consistent in vitro activity against ESBL-positive isolates of E. coli (n=5674; MIC₉₀, 0.5mg/L, 99.5% susceptible), K. pneumoniae (n=7097; MIC₉₀, 2mg/L, 97.0% susceptible) and K. oxytoca (n = 565; MIC₉₀, 1mg/L, 96.8% susceptible). Isolates identified as metallo-β-lactamase-positive (n=242) were not susceptible to ceftazidime/avibactam but were susceptible to tigecycline (76.9%) and colistin (n=194 isolates tested; 92.8%).

CONCLUSIONS

Clinical Enterobacteriaceae isolates, including ESBL-positive phenotypes, collected globally (excluding North America) from 2012-2016 were highly susceptible to ceftazidime/avibactam, suggesting it is a useful agent for serious infections caused by multidrug-resistant organisms belonging to the family Enterobacteriaceae when therapeutic options are limited.

Nationwide surveillance of antimicrobial resistance among clinically important Gram-negative bacteria, with an emphasis on carbapenems and colistin: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2018

Multicentre surveillance of antimicrobial susceptibility of clinically important Gram-negative bacteria (GNB) from 16 Taiwanese hospitals was performed. Escherichia coli (n = 398), Klebsiella pneumoniae (n = 346), Pseudomonas aeruginosa (n = 252) and Acinetobacter baumannii complex (ABC) (n = 188) bloodstream isolates, non-typhoidal Salmonella (n = 230) and Shigella flexneri (n = 18) from various sources were collected. Antimicrobial MICs were determined using broth microdilution. Genes encoding K. pneumoniae carbapenemases (KPCs), New Delhi metallo-β-lactamases (NDMs), Verona integron-encoded metallo-β-lactamase (VIM), OXA-48-like carbapenemase (OXA-48) as well as mcr-1-5 genes were detected by molecular methods. Rates of carbapenem non-susceptibility were 2.8%, 9.0%, 0.4%, 0%, 10.3% and 48.8% for E. coli, K. pneumoniae, Salmonella, Shigella, P. aeruginosa and ABC, respectively. For carbapenemases, one (0.3%) E. coli harboured bla_NDM-1. Fifteen (4.3%), two (0.6%) and two (0.6%) K. pneumoniae contained bla_KPC, bla_OXA-48 and bla_VIM, respectively. Two (0.5%) E. coli and fourteen (4.0%) K. pneumoniae were non-wild-type according to the colistin MIC. Among Enterobacteriaceae with a colistin MIC ≥ 2 mg/L, mcr-1 was detected in one E. coli, two K. pneumoniae and three Salmonella spp. All three mcr-1-positive Salmonella isolates were collected from community-acquired infections; none of the six mcr-1-positive Enterobacteriaceae were carbapenem-resistant. Carbapenem resistance has increased among clinically important GNB, especially among hospital-acquired infections. bla_KPC, especially the bla_KPC-2 variant, was detected in approximately one-half of the carbapenem-resistant K. pneumoniae isolates in this study. Although resistance rates to colistin remained low among Enterobacteriaceae, the finding of mcr-1 from different species raises concern of potential dissemination.

Antimicrobial activities of ceftazidime-avibactam, ceftolozane-tazobactam, and other agents against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolated from intensive care units in Taiwan: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan in 2016

Objective

The aim of this study was to investigate the in vitro antimicrobial susceptibilities of clinically important Gram-negative bacteria from seven intensive care units in Taiwan in 2016.

Materials and methods

In total, 300 non-duplicate isolates of Escherichia coli (n=100), Klebsiella pneumoniae (n=100), and Pseudomonas aeruginosa (n=100) collected from 300 patients were studied. The minimum inhibitory concentrations (MICs) of these isolates to antimicrobial agents were determined using the broth microdilution method. Carbapenemase-encoding genes (bla _KPC, bla _NDM, bla _IMP, bla _VIM, and bla _OXA-48-like) were studied for the isolates that were not susceptible to any carbapenems. Sequencing analysis of the mcr genes (mcr-1-5) was conducted for all isolates with colistin MICs ≥4 mg/L.

Results

Ertapenem non-susceptibility was detected in 3% (n=3) E. coli and 12% (n=12) K. pneumoniae isolates. The susceptibility rates of imipenem, ceftazidime-avibactam (CAZ-AVB), and ceftolozane-tazobactam (CLZ-TAZ) were 99%, 99%, and 88%, respectively, for E. coli, 91%, 100%, and 80%, respectively, for K. pneumoniae, and 66%, 91%, and 93%, respectively, for P. aeruginosa. Carbapenemase-encoding genes were not detected in E. coli, were detected in four (33.3%) K. pneumoniae isolates that were not susceptible to ertapenem (three harboring bla _KPC and one harboring bla _OXA-48-like), and were not detected in P. aeruginosa isolates that were not susceptible to imipenem. One K. pneumoniae isolate was resistant to colistin (MIC 4 mg/L) and negative for mcr genes.

Conclusion

CAZ-AVB exhibited excellent activity against carbapenem-resistant Enterobacteriaceae, and CLZ-TAZ exhibited good activity against imipenem-resistant P. aeruginosa.

Carbapenem-Resistant Enterobacteriaceae Infections: Taiwan Aspects

Carbapenem-resistant Enterobacteriaceae (CRE), a major resistance concern emerging during the last decade because of significantly compromising the efficacy of carbapenem agents, has currently become an important focus of infection control. Many investigations have shown a high association of CRE infections with high case-fatality rates. In Taiwan, a few surveys observed that a significant proportion (29–47%) of the CR-Klebsiella pneumoniae isolates harbored a plasmidic allele encoding K. pneumoniae carbapenemases (KPC, especially KPC-2). A significant increase in the number of oxacillinase (OXA)-48-like carbapenemases among CR-K. pneumoniae isolates was observed between 2012 and 2015. By striking contrast, isolates of CR-Escherichia coli and CR-Enterobacter species in Taiwan had a much lower percentage of carbapenemase production than CR-K. pneumoniae isolates. This differs from isolates found in China as well as in the India subcontinent. Apart from the hospital setting, CRE was also cultured from the inpatients from communities or long-term care facilities (LTCF). Therefore, implementation of regular CRE screening of LTCF residents, strict disinfectant use in nursing homes and hospital settings, and appropriate control of antibiotic prescriptions is suggested to alleviate the spread of clinical CRE isolates in Taiwan. Although there are some promising new antibiotics against CRE, such as ceftazidime-avibactam, meropenem-vaborbactam, aztreonam-avibactam and cefiderocol, these agents are not available in Taiwan currently. Therefore, in order to effectively decrease case-fatality rates among patients with the infections owing to carbapenemase-producing CRE isolates, combination antibiotic schemes, including colistin (or amikacin) and/or tigecycline in combination with an anti-pseudomonal carbapenem agent, remain the mainstay for treating clinical CRE infections.