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1.
J Med Microbiol ; 72(6)2023 Jun.
Article in English | MEDLINE | ID: mdl-37294294

ABSTRACT

Introduction. Carbapenemase-producing Enterobacteriaceae (CPE) have emerged as a global threat to public health and clinical practice.Hypothesis/Gap Statement. In Thailand, reports describing CPEs carrying bla NDM and bla OXA-48-like genes have been increasing recently; however, data on detailed plasmid analysis and temporal shift of sequence type and carbapenemase type are limited.Aim. In this study, we analysed whole-genome sequencing (WGS) data of clinically isolated carbapenemase-producing Klebsiella pneumoniae (CPKP) to reveal the molecular epidemiology of CPKP in a tertiary-care hospital in Bangkok, Thailand.Methodology. Seventy-seven non-duplicated CPKP isolates collected during 2013-2016 were examined for their drug-resistance genes, sequence types and phylogenetic relationships.Results. All the tested isolates possessed carbapenemase gene(s), and the major type of carbapenemase gene in 2014-2015 was bla NDM-1, whereas isolates in 2016 harboured more bla OXA-232 than bla NDM-1. Other carbapenemase gene variants, such as bla NDM-4, bla NDM-5, bla OXA-48, bla OXA-181 and bla IMP-14 were detected in some CPKP isolates. Furthermore, this study revealed that CPKP co-harbouring two genes, bla NDM-1 and bla OXA-232 or bla OXA-181, emerged during this period. Notably, such isolates co-carrying the two carbapenemase genes emerged in three different sequence types, even in a single hospital, and then spread clonally. The WGS of CPKP revealed a temporal shift of the predominant carbapenemase genes from bla NDM-1 to bla OXA-232 along with a variation in other carbapenemase gene types within a span of 4 years.Conclusion. Our findings suggest that a substantial change in CPE types occurred in Thailand and potentially in Southeast Asian countries.


Subject(s)
Carbapenem-Resistant Enterobacteriaceae , Enterobacteriaceae Infections , Humans , Klebsiella pneumoniae/genetics , Carbapenem-Resistant Enterobacteriaceae/genetics , Thailand/epidemiology , Phylogeny , Enterobacteriaceae Infections/epidemiology , beta-Lactamases/genetics , Bacterial Proteins/genetics , Microbial Sensitivity Tests
2.
J Clin Microbiol ; 60(12): e0108022, 2022 12 21.
Article in English | MEDLINE | ID: mdl-36445367

ABSTRACT

Despite frequent identification of plasmids carrying carbapenemase genes, the transfer of plasmids carrying carbapenemase genes is not well recognized in clinical settings because of technical limitations. To investigate the detailed mechanisms of the spread of carbapenem-resistant Enterobacteriaceae (CRE), we performed multifaceted genomic surveillance of CRE isolates in Thailand and analyzed their plasmidome. We analyzed 371 Enterobacteriaceae isolates carrying blaNDM-1 and 114 Enterobacteriaceae isolates carrying blaNDM-5 obtained from clinical samples of 473 patients in 11 representative hospitals located in six provinces in Thailand between 2012 and 2017. The complete structures of plasmids carrying blaNDM and chromosomal phylogeny were determined by combining Southern blotting hybridization analysis and our previously performed whole-genome short-read sequencing data. Dissemination of the blaNDM-5 gene among the Enterobacteriaceae isolates in Thailand was mainly owing to the nationwide clonal spread of Escherichia coli ST410 and regional clonal spreads of Escherichia coli ST361 and ST405. Analysis of blaNDM-1-carrying isolates revealed nationwide dissemination of two specific plasmids and nationwide clonal dissemination of Klebsiella pneumoniae ST16 accompanied with regional disseminations of three distinctive K. pneumoniae clones (ST231, ST14, and ST147) with different plasmids. Dissemination of CRE carrying blaNDM in Thailand is mainly based on nationwide clonal expansions of E. coli ST410 carrying blaNDM-5 and K. pneumoniae ST16 carrying blaNDM-1, nationwide dissemination of two distinctive plasmids carrying blaNDM-1, and accumulation of clonal expansions in regional areas. Although the overuse of antibiotics can promote CRE dissemination, the limited variety of transmitters highlights the importance of preventing horizontal dissemination among patients.


Subject(s)
Carbapenem-Resistant Enterobacteriaceae , Enterobacteriaceae Infections , Humans , Carbapenem-Resistant Enterobacteriaceae/genetics , Escherichia coli/genetics , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae Infections/drug therapy , Thailand/epidemiology , Microbial Sensitivity Tests , beta-Lactamases/genetics , Enterobacteriaceae/genetics , Plasmids/genetics , Klebsiella pneumoniae/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use
4.
J Phys Chem A ; 126(36): 6336-6347, 2022 Sep 15.
Article in English | MEDLINE | ID: mdl-36053017

ABSTRACT

Materials exhibiting higher mobility than conventional organic semiconducting materials, such as fullerenes and fused thiophenes, are in high demand for applications in printed electronics. To discover new molecules that might show improved charge mobility, the adaptive design of experiments (DoE) to design molecules with low reorganization energy was performed by combining density functional theory (DFT) methods and machine learning techniques. DFT-calculated values of 165 molecules were used as an initial training dataset for a Gaussian process regression (GPR) model, and five rounds of molecular designs applying the GPR model and validation via DFT calculations were executed. As a result, new molecules whose reorganization energy is smaller than the lowest value in the initial training dataset were successfully discovered.

5.
JAC Antimicrob Resist ; 4(4): dlac084, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35983103

ABSTRACT

Background: Klebsiella pneumoniae ST258 and ST11 carrying bla KPC are among the most widespread carbapenem-resistant K. pneumoniae strains worldwide. Our carbapenem-resistant Enterobacteriaceae surveillance in Thailand revealed a nationwide dissemination of K. pneumoniae ST16 isolates carrying bla NDM-1 and bla OXA-232. Objectives: To analyse the genomic details of this nationwide dissemination by focusing on plasmids and virulence factors. Methods: Using WGS data of 119 K. pneumoniae ST16 isolates carrying bla NDM-1 obtained in our previous surveillance study, clonality of chromosomes and plasmids of the isolates with carriage of virulence factors was evaluated. Results: Of the 119 isolates, 111 carried plasmid pKP151_NDM1, and all 104 isolates harbouring bla OXA-232 carried plasmid pKP151_OXA232. These 104 K. pneumoniae ST16 isolates showing chromosomal clonality possessed both pKP151_NDM1 and pKP151_OXA232, demonstrating clonal dissemination of K. pneumoniae ST16 with these plasmids. The isolates had essentially similar virulence factors as those of K. pneumoniae ST16 clones carrying bla KPC, which were recently reported as highly invasive clones in Brazil. Conclusions: The potential global dissemination of these invasive clones with resistance to several antibiotics highlights the importance of appropriate monitoring and strict standard precautions.

7.
Lancet Reg Health West Pac ; 23: 100442, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35359913

ABSTRACT

The assessment of the efficacy and safety of coronavirus disease 2019 (COVID-19) vaccines in actual practice is extremely important, and monitoring efforts are being implemented worldwide. In Japan, a joint council in the Ministry of Health, Labour and Welfare is held every two to three weeks to summarise information on the adverse events following COVID-19 vaccination, with careful assessment of individual case safety reports and comparison with background incidence rates. In 2021, the joint council mainly reviewed anaphylaxis, death, myocarditis/pericarditis, and thrombosis with thrombocytopenia syndrome. These activities resulted in several safety-related regulatory actions, including the revision of vaccine package inserts with warnings about myocarditis/pericarditis. International sharing of vaccine safety information, as well as details of the evaluation systems, is important for international discussion and decision-making on better safety monitoring of COVID-19 vaccines.

9.
mBio ; 12(3): e0018621, 2021 06 29.
Article in English | MEDLINE | ID: mdl-34154401

ABSTRACT

The worldwide dissemination of carbapenem-resistant Enterobacteriaceae (CRE) poses a critical human health issue by limiting the range of antibiotics that are usable in the treatment of common bacterial infections. Along with CRE, carbapenem heteroresistance has disseminated worldwide, which is described as different levels of carbapenem resistance within a seemingly isogenic bacterial population. Unstable carbapenem resistance will likely lead to unexpected treatment failure due to the enhanced resistance after initiation of treatment, contradicting antimicrobial susceptibility test results. Porin mutation and tandem amplification of the carbapenemase gene have been reported as mechanisms underlying enhanced carbapenem resistance. In this study, we identified multimerization of plasmids carrying carbapenemase genes, by using Southern blotting, whole-genome sequencing, and quantitative PCR (qPCR) analysis for the CRE isolates obtained in our previous surveillance in Osaka, Japan. Plasmids harboring a carbapenemase gene were multimerized by recA, likely through recombination at two consecutive sets of transposase genes of the IS91 family, thereby producing various plasmids of discrete sizes in a single bacterial cell of an Escherichia coli isolate. This multimerization resulted in increased copy numbers of carbapenemase genes, leading to enhanced gene transcription as well as carbapenem resistance. Prior exposure to meropenem further increased the copy number of carbapenemase genes, readily resulting in enhancement of carbapenem resistance. This mechanism may lead to clinical treatment failure by sifting antimicrobial resistance after the treatment initiation. IMPORTANCE We demonstrated the multimerization of plasmids harboring carbapenemase genes, and multimeric plasmids of various discrete sizes existed in a host bacterial cell of Escherichia coli. Plasmid multimerization along with increased copy numbers of carbapenemase genes resulted in enhanced carbapenemase resistance, which was readily accelerated by an overnight preexposure to meropenem. This mechanism may lead to treatment failure in clinical settings after the initiation of antimicrobial therapy.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Carbapenem-Resistant Enterobacteriaceae/genetics , Carbapenems/pharmacology , Plasmids/chemistry , Plasmids/genetics , beta-Lactamases/genetics , Carbapenem-Resistant Enterobacteriaceae/drug effects , Enterobacteriaceae Infections/microbiology , Humans , Microbial Sensitivity Tests , Multilocus Sequence Typing
10.
Sensors (Basel) ; 21(4)2021 Feb 09.
Article in English | MEDLINE | ID: mdl-33572363

ABSTRACT

Here we report the improved Cyclo olefin polymer (COP) microfluidic chip and polymerase chain reaction (PCR) amplification system for point-of-care testing (POCT) in rapid detection of Carbapenem-resistant Enterobacteriaceae (CRE). The PCR solution and thermal cycling is controlled by the relative gravitational acceleration (7G) only and is expected to pose minimal problem in operation by non-expert users. Detection is based on identifying the presence of carbapenemase encoding gene through the corresponding fluorescence signal after amplification. For preliminary tests, the device has been demonstrated to detect blaIMP-6 from patients stool samples. From the prepared samples, 96.4 fg/µL was detected with good certainty within 15 min (~106 thermocycles,) which is significantly faster than the conventional culture plate method. Moreover, the device is expected to detect other target genes in parallel as determination of the presence of blaNDM-1 and blaOXA-23 from control samples has also been demonstrated. With the rising threat of drug-resistant bacteria in global healthcare, this technology can greatly aid the health sector by enabling the appropriate use of antibiotics, accelerating the treatment of carriers, and suppressing the spread.


Subject(s)
Convection , Pharmaceutical Preparations , Polymerase Chain Reaction , Acceleration , Anti-Bacterial Agents/therapeutic use , Bacterial Proteins , Humans , Microbial Sensitivity Tests
11.
mSystems ; 5(6)2020 Nov 10.
Article in English | MEDLINE | ID: mdl-33172969

ABSTRACT

Carbapenem-resistant Enterobacteriaceae (CRE) infections, high in morbidity and mortality, pose serious clinical challenges due to limited treatment options. A previous CRE surveillance study on 1,507 patients from 43 hospitals in Osaka, Japan, revealed that 12% of patients carried CRE and that 95% of the CRE isolates were IMP-type carbapenemase producers. Here, the mechanisms for this regional dissemination of a single carbapenemase gene were investigated. Since the dissemination of CRE is primarily due to the transmission of carbapenemase genes located on plasmids, we analyzed the plasmidome of 230 CRE isolates carrying bla IMP by whole-genome sequencing and Southern blotting. bla IMP-6 was found to be predominantly disseminated among chromosomally distinct isolates through the pKPI-6 plasmid. Underlying the vast clonal dissemination of pKPI-6, various subpopulations deriving from pKPI-6 were identified, which had acquired advantages for the dissemination of CRE isolates. A cluster exhibiting heteroresistance against meropenem by the transcriptional regulation of bla IMP-6 caused an outbreak likely through covert transmission of bla IMP-6 For stable carriage of bla IMP-6, they occasionally integrated bla IMP-6 on their chromosomes. In addition, we detected one isolate that broadened the range of antimicrobial resistance through a single point mutation in bla IMP-6 on pKPI-6. Multifaceted analysis of the plasmidome granted us more accurate perspectives on the horizontal spread of CRE isolates, which is difficult to trace only by comparing the whole genomes. This study revealed the predominant spread of a specific carbapenemase-encoding plasmid accompanying the emergence of phenotypically diverse derivatives, which may facilitate further dissemination of CRE in various environments.IMPORTANCE Global dissemination of carbapenem-resistant Enterobacteriaceae (CRE) threatens human health by limiting the efficacy of antibiotics even against common bacterial infections. Carbapenem resistance, mainly due to carbapenemase, is generally encoded on plasmids and is spread across bacterial species by conjugation. Most CRE epidemiological studies have analyzed whole genomes or only contigs of CRE isolates. Here, plasmidome analysis on 230 CRE isolates carrying bla IMP was performed to shed light into the dissemination of a single carbapenemase gene in Osaka, Japan. The predominant dissemination of bla IMP-6 by the pKPI-6 plasmid among genetically distinct isolates was revealed, as well as the emergences of pKPI-6 derivatives that acquired advantages for further disseminations. Underlying vast clonal dissemination of a carbapenemase-encoding plasmid, heteroresistance was found in CRE offspring, which was generated by the transcriptional regulation of bla IMP-6, stabilization of bla IMP-6 through chromosomal integration, or broadened antimicrobial resistance due to a single point mutation in bla IMP-6.

12.
J Intensive Care ; 8: 25, 2020.
Article in English | MEDLINE | ID: mdl-32308985

ABSTRACT

BACKGROUND: Neutrophil extracellular traps (NETs) are fibrous structures released from activated neutrophils. NET formation has been reported to be associated with acute respiratory distress syndrome (ARDS). However, there are no reports dealing with serial changes of NET formation in tracheal aspirate of ARDS patients. CASE PRESENTATION: We report three cases of ARDS. Case 1 is a 69-year-old man with necrotizing fasciitis of the buttocks, case 2 is a 49-year-old woman with extensive burns (80% of total body surface), and case 3 is a 73-year-old woman with severe bacterial pneumonia. We found abundant expression of citrullinated histone H3 (Cit-H3) and the formation of NETs at the onset of ARDS in all cases. The amounts of Cit-H3 and NETs decreased with the amelioration of respiratory failure in cases 1 and 2. In case 2, the amounts of Cit-H3 and NETs increased with aggravation of infection and respiratory status. In case 3, the abundant expression of Cit-H3 and NETs persisted; the patient did not recover from ARDS and eventually died. Cit-H3 and NETs were found in tracheal aspirates even if the patients had no direct injury to the lung as in cases 1 and 2. CONCLUSIONS: In these three cases, the formation of NETs was observed in tracheal aspirate of patients with ARDS by either direct or indirect insults to the lung. The amount of NET formation changed dynamically over the clinical course of each patient.

14.
Int J Antimicrob Agents ; 55(3): 105905, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31991221

ABSTRACT

BACKGROUND: Limited treatment options complicate management of infections with New Delhi metallo-ß-lactamase (NDM)-producing organisms. The efficacy of combination therapy with meropenem (MEM) and cefmetazole (CMZ) was assessed against NDM-producing Enterobacteriaceae. MATERIALS AND METHODS: Twelve Escherichia coli clinical isolates harbouring blaNDM-1 and a positive control E. coli BAA-2469 harbouring blaNDM-1 were studied. Minimum inhibitory concentrations (MICs) of MEM, ertapenem (ERT) and CMZ were determined by broth microdilution. Checkerboard and time-kill assays were performed to confirm the in vitro efficacy of the MEM/CMZ combination. Scanning electron microscopy, kinetic studies and whole-genome sequence analysis were used to determine the antimicrobial resistance mechanisms. RESULTS: MICs of MEM, ERT and CMZ in monotherapy ranged from 8 to 32, 16 to 128, and 32 to 512 µg/mL, respectively. In the checkerboard assay, MEM/ERT resulted in no synergy, whereas MEM/CMZ showed a synergistic effect in all the tested isolates. Furthermore, the MIC of MEM in combination decreased by 2- to 8-fold compared with that of MEM alone. The time-kill study revealed a bactericidal effect in 4 of 13 isolates at 24 h. Scanning electron microscopy showed spheroidisation of the bacterial cell in the MEM/CMZ combination; this was not observed in single antibiotic conditions. Kinetic studies indicated CMZ was a better antagonist for NDM-1 than ERT. Whole-genome sequence analysis did not reveal any explainable differences between isolates susceptible and those non-susceptible to combination therapy. CONCLUSION: In vitro studies showed the potential effectiveness of MEM/CMZ combination therapy against NDM-producing organisms.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cefmetazole/pharmacology , Enterobacteriaceae Infections/drug therapy , Enterobacteriaceae/drug effects , Meropenem/pharmacology , Anti-Bacterial Agents/therapeutic use , Cefmetazole/therapeutic use , Drug Therapy, Combination , Enterobacteriaceae/metabolism , Enterobacteriaceae Infections/microbiology , Ertapenem/pharmacology , Humans , Meropenem/therapeutic use , beta-Lactamases/biosynthesis
15.
J Glob Antimicrob Resist ; 21: 195-199, 2020 06.
Article in English | MEDLINE | ID: mdl-31627024

ABSTRACT

OBJECTIVES: To analyse plasmids carrying blaIMP-6 in Klebsiella pneumoniae isolates obtained from multicentre carbapenem-resistant Enterobacteriaceae surveillance. METHODS: Plasmids harbouring blaIMP-6 were characterised by the whole-genome sequencing of four Klebsiella pneumoniae isolates carrying blaIMP-6, and compared with the pKPI-6 plasmid, which is widespread in western Japan, through pulsed-field gel electrophoresis, Southern blotting, bacterial conjugation, and qPCR. RESULTS: Whole-genome sequencing analysis revealed that three of the four isolates carried approximately 50 kbp plasmids similar to the pKPI-6 plasmid; however, one isolate carried a 250 kbp plasmid harbouring blaIMP-6 (pE196_IMP6). So far, all of the reported plasmids carrying blaIMP-6 were similar to the pKPI-6 plasmid, and this plasmid was a novel blaIMP6-carrier. The size and transferability of this plasmid was confirmed by Southern hybridisation and conjugation experiments. It was demonstrated that the generation of plasmid pE196_IMP6 was due to an intramolecular transposition mediated by IS26, and a homologous recombination between plasmids pKPI-6 and pE013 that was obtained from another carbapenem-resistant Enterobacteriaceae isolate in this analysis. As a result of co-integration with pE013, pE196_IMP6 acquired six additional pairs of type II toxin-antitoxin systems that pKPI-6 does not carry. Transcription of all of the toxin-antitoxin systems were confirmed in an isolate carrying pE196_IMP6 by qPCR. CONCLUSIONS: This study detected a novel plasmid carrying blaIMP-6, and revealed the origin of this plasmid. Toxin-antitoxin system acquisition could enable pE196_IMP6 maintenance persistently through successions, even without selection pressure by the clinical usage of antimicrobials, generating broad dissemination and longer carbapenem-resistant Enterobacteriaceae colonisation duration in patients.


Subject(s)
Carbapenem-Resistant Enterobacteriaceae , Klebsiella pneumoniae , Humans , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , beta-Lactamases/genetics , Carbapenem-Resistant Enterobacteriaceae/genetics , Carbapenems/pharmacology , Genomics , Japan , Klebsiella pneumoniae/genetics , Microbial Sensitivity Tests , Plasmids/genetics
16.
BMC Res Notes ; 12(1): 740, 2019 Nov 09.
Article in English | MEDLINE | ID: mdl-31706328

ABSTRACT

OBJECTIVE: Carbapenem-resistant Enterobacteriaceae (CRE) are among the most severe threats to public and clinical health because of their high levels of resistance to various antibiotics. We assessed the efficacy of combination therapy with meropenem (MEM) and cefmetazole (CMZ) against Imipenemase (IMP)-producing CRE, using the checkerboard method and time-killing assay on 13 Enterobacteriaceae isolates harboring blaIMP-1 (4 Enterobacter hormaechei, 5 Escherichia coli, and 4 Klebsiella pneumoniae isolates) and 13 isolates harboring blaIMP-6 (8 E. coli and 5 K. pneumoniae isolates). RESULTS: Minimum inhibitory concentrations (MICs) of MEM and CMZ ranged from 2 to 64 and 64 to 2048 µg/mL, respectively. Checkerboard method demonstrated the synergy of the MEM/CMZ combination in all the tested IMP-producing CRE isolates, and the time-kill assay indicated a bactericidal effect for both blaIMP-1 and blaIMP-6 positive CRE when MEM/CMZ combination was used. In vitro, the MEM/CMZ combination was potentially effective against IMP-1- or IMP-6-producing CRE. Further investigations including in vivo animal studies and clinical studies are warranted to corroborate the clinical utility of the novel combination therapy.


Subject(s)
Bacterial Proteins/biosynthesis , Carbapenem-Resistant Enterobacteriaceae/drug effects , Cefmetazole/pharmacology , Meropenem/pharmacology , beta-Lactamases/biosynthesis , Drug Therapy, Combination , Escherichia coli/drug effects , Microbial Sensitivity Tests , Microbial Viability/drug effects , Time Factors
17.
Article in English | MEDLINE | ID: mdl-31297191

ABSTRACT

Background: Active surveillance has the potential to prevent nosocomial transmission of carbapenem-resistant Acinetobacter baumannii (CRAB). We assessed whether rapid diagnosis using clinical specimen-direct loop-mediated isothermal amplification (LAMP), a rapid molecular diagnostic assay, and subsequent intervention, could reduce CRAB nosocomial transmission in intensive care units (ICUs). Methods: A before and after (quasi-experimental) study was conducted in two ICUs at the Mahidol University Faculty of Medicine Ramathibodi Hospital with 3 months of observational period followed by 9 months of interventional period. All patients were screened for CRAB using both the culture and LAMP method from rectal swab and/or bronchial aspirates (intubated patients only) upon admission, weekly thereafter, and upon discharge. During the pre-intervention period, we performed contact precautions based on culture results. In contrast, during the intervention period, we initiated contact precautions within a few hours after sample collection on the basis of LAMP results. Results: A total of 1335 patients were admitted to the ICUs, of which 866 patients (pre-intervention period: 187; intervention period: 679) were eligible for this study. Incidence rate of CRAB infection decreased to 20.9 per 1000 patient-days in the intervention period from 35.2 in the pre-intervention period (P < 0.02). The calculated hazard ratio of CRAB transmission was 0.65 (95% confidence interval [CI], 0.44-0.97). Risk factors for CRAB acquisition included exposure to carbapenem (hazard ratio, 2.54 [95% CI: 1.61-5.57]). Conclusions: LAMP screening for CRAB upon ICU admission proved feasible for routine clinical practice. Rapid screening using LAMP followed by early intervention may reduce CRAB transmission rates in ICUs when compared to conventional intervention.


Subject(s)
Acinetobacter Infections/epidemiology , Acinetobacter baumannii/isolation & purification , Cross Infection/epidemiology , Drug Resistance, Multiple, Bacterial , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , Acinetobacter baumannii/drug effects , Aged , Carbapenems , Cross Infection/microbiology , Early Diagnosis , Female , Humans , Incidence , Infection Control , Intensive Care Units , Japan/epidemiology , Male , Middle Aged , Non-Randomized Controlled Trials as Topic , Watchful Waiting
18.
Intern Med ; 58(18): 2621-2625, 2019 Sep 15.
Article in English | MEDLINE | ID: mdl-31118388

ABSTRACT

Objective The importance of antimicrobial stewardship is increasingly highlighted in this age of antimicrobial resistance. A better comprehension of adverse drug events (ADEs) can promote the appropriate use of antibiotics. We aimed to quantify the incidence of ADEs associated with broad-spectrum systemic antibiotics in a hospital setting. Methods We conducted a six-month prospective, observational study at Osaka University Hospital to describe the incidence of ADEs in patients hospitalized in general wards undergoing treatment with broad-spectrum antibiotics [carbapenems, piperacillin/tazobactam (PIPC/TAZ), and anti-methicillin-resistant Staphylococcus aureus agents]. The occurrence of ADE was defined as any cardiac, gastrointestinal, hepatobiliary, renal, neurologic, hematologic, dermatologic, or musculoskeletal manifestation after 48 hours or more of systemic antibiotic therapy. Results The 3 most frequently prescribed antibiotics were PIPC/TAZ (242 cases), meropenem (181 cases), and vancomycin (92 cases). Of 689 patients, 118 (17.1%) experienced ADEs, including gastrointestinal (6.4%), hepatobiliary (4.2%), dermatologic (2.5%), and renal (2.3%) manifestations. Patients treated with PIPC/TAZ, meropenem, doripenem, vancomycin, daptomycin, and teicoplanin developed ADEs at rates of 20.7%, 16.0%, 15.4%, 19.6%, 11.8%, and 10.9%, respectively. Conclusion Our study provides a quantitative value for the incidence of ADEs associated with broad-spectrum antibiotics in clinical practice. To optimize patient safety, clinicians need to be aware of the risks associated with antibiotic administration.


Subject(s)
Anti-Bacterial Agents/adverse effects , Drug-Related Side Effects and Adverse Reactions/epidemiology , Adult , Anti-Bacterial Agents/therapeutic use , Carbapenems/adverse effects , Drug-Related Side Effects and Adverse Reactions/etiology , Female , Humans , Incidence , Male , Meropenem/adverse effects , Middle Aged , Piperacillin, Tazobactam Drug Combination/adverse effects , Prospective Studies , Vancomycin/adverse effects , Young Adult
19.
Microb Drug Resist ; 25(6): 839-845, 2019.
Article in English | MEDLINE | ID: mdl-30835635

ABSTRACT

Purpose: Optimal treatment regimens are yet to be established for carbapenemase-producing Enterobacteriaceae (CPE). We assessed the in vitro efficacy of meropenem (MEM) and cefmetazole (CMZ) combination treatment against blaKPC-2-positive Enterobacteriaceae, in comparison with that of double-carbapenem therapy using ertapenem (ERT). Materials and Methods: We performed checkerboard assay for 10 blaKPC-2-positive clinical isolates and Klebsiella pneumoniae BAA-1705 (possessing blaKPC-2), with synergistic effect being defined by a fractional inhibitory concentration index of ≤0.5. Subsequently, we conducted time-kill assays using K. pneumoniae BAA-1705 with an initial inoculum of 104-107 colony forming unit (CFU)/mL. Bactericidal effect was defined as the reduction of initial bacterial count by ≥103 CFU/mL in 24 hr. Finally, we applied scanning electron microscopy to observe morphological changes induced by the combination of MEM and CMZ. Results: Checkerboard assays revealed a synergistic effect in 7 out of 11 blaKPC-2 -positive Enterobacteriaceae when the MEM and CMZ combination was used, and no effect when the MEM and ERT combination was used. The minimum inhibitory concentration of MEM decreased 4-8-fold when combined with CMZ. Time-kill assays with an initial inoculum of 5 × 105 CFU/mL revealed regrowth under the combination of MEM and ERT (0.25 × minimum inhibitory concentration [MIC] each), whereas the combination of 0.25 × MIC each of MEM and CMZ exhibited bactericidal effect. Scanning electron microscopy results demonstrated that the combination of 0.5 × MIC MEM and 0.5 × MIC CMZ facilitated bacterial cell lysis compared with each antibiotic alone. Conclusion: The combination therapy using MEM and CMZ potentially has bactericidal effect against KPC-producing Enterobacteriaceae.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Carbapenem-Resistant Enterobacteriaceae/drug effects , Cefmetazole/pharmacology , Enterobacteriaceae Infections/drug therapy , Meropenem/pharmacology , beta-Lactamases/metabolism , Carbapenem-Resistant Enterobacteriaceae/metabolism , Carbapenems/pharmacology , Drug Synergism , Drug Therapy, Combination/methods , Enterobacteriaceae Infections/microbiology , Ertapenem/pharmacology , Humans , Klebsiella Infections/drug therapy , Klebsiella Infections/microbiology , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/metabolism , Microbial Sensitivity Tests/methods
20.
Front Microbiol ; 10: 149, 2019.
Article in English | MEDLINE | ID: mdl-30800104

ABSTRACT

Colistin is used as an alternative therapeutic for carbapenemase-producing Enterobacteriaceae (CPE) infections which are spreading at a very high rate due to the transfer of carbapenemase genes through mobile genetic elements. Due to the emergence of mcr-1, the plasmid-mediated colistin resistance gene, mcr-1-positive Enterobacteriaceae (MCRPEn) pose a high risk for the transfer of mcr-1-carrying plasmid to CPE, leading to a situation with no treatment alternatives for infections caused by Enterobacteriaceae possessing both mcr-1 and carbapenemase genes. Here, we report the application of PCR-dipstick-oriented surveillance strategy to control MCRPEn and CPE by conducting the PCR-dipstick technique for the detection of MCRPEn and CPE in a tertiary care hospital in Thailand and comparing its efficacy with conventional surveillance method. Our surveillance results showed a high MCRPEn (5.9%) and CPE (8.7%) carriage rate among the 219 rectal swab specimens examined. Three different CPE clones were determined by pulsed-field gel electrophoresis (PFGE) whereas only two MCRPEn isolates were found to be closely related as shown by single nucleotide polymorphism-based phylogenetic analysis. Whole genome sequencing (WGS) and plasmid analysis showed that MCRPEn carried mcr-1 in two plasmids types-IncX4 and IncI2 with ~99% identity to the previously reported mcr-1-carrying plasmids. The identification of both MCRPEn and CPE in the same specimen indicates the plausibility of plasmid-mediated transfer of mcr-1 genes leading to the emergence of colistin- and carbapenem-resistant Enterobacteriaceae. The rapidity (<2 h) and robust sensitivity (100%)/specificity (~99%) of PCR-dipstick show that this specimen-direct screening method could aid in implementing infection control measures at the earliest to control the dissemination of MCRPEn and CPE.

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