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1.
PLoS One ; 19(5): e0301092, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38718028

RESUMO

Globally, the rapid aging of the population is predicted to become even more severe in the second half of the 21st century. Thus, it is expected to establish a growing expectation for innovative, non-invasive health indicators and diagnostic methods to support disease prevention, care, and health promotion efforts. In this study, we aimed to establish a new health index and disease diagnosis method by analyzing the minerals and free amino acid components contained in hair shaft. We first evaluated the range of these components in healthy humans and then conducted a comparative analysis of these components in subjects with diabetes, hypertension, androgenetic alopecia, major depressive disorder, Alzheimer's disease, and stroke. In the statistical analysis, we first used a student's t test to compare the hair components of healthy people and those of patients with various diseases. However, many minerals and free amino acids showed significant differences in all diseases, because the sample size of the healthy group was very large compared to the sample size of the disease group. Therefore, we attempted a comparative analysis based on effect size, which is not affected by differences in sample size. As a result, we were able to narrow down the minerals and free amino acids for all diseases compared to t test analysis. For diabetes, the t test narrowed down the minerals to 15, whereas the effect size measurement narrowed it down to 3 (Cr, Mn, and Hg). For free amino acids, the t test narrowed it down to 15 minerals. By measuring the effect size, we were able to narrow it down to 7 (Gly, His, Lys, Pro, Ser, Thr, and Val). It is also possible to narrow down the minerals and free amino acids in other diseases, and to identify potential health indicators and disease-related components by using effect size.


Assuntos
Aminoácidos , Cabelo , Humanos , Cabelo/química , Masculino , Aminoácidos/análise , Aminoácidos/metabolismo , Feminino , Pessoa de Meia-Idade , Adulto , Alopecia/diagnóstico , Idoso , Minerais/análise , Minerais/metabolismo , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/metabolismo , Acidente Vascular Cerebral , Hipertensão , Transtorno Depressivo Maior/diagnóstico , Diabetes Mellitus/diagnóstico , Estudos de Casos e Controles
3.
Int J Mol Sci ; 25(8)2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38674079

RESUMO

Information regarding Klebsiella aerogenes haboring carbapenemase in Japan is limited. A comprehensive nationwide survey was conducted from September 2014 to December 2022, and 67 non-duplicate strains of carbapenem-resistant K. aerogenes were isolated from 57 healthcare facilities in Japan. Through genetic testing and whole-genome sequencing, six strains were found to possess carbapenemases, including imipenemase (IMP)-1, IMP-6, New Delhi metallo-ß-lactamase (NDM)-1, and NDM-5. The strain harboring blaNDM-5 was the novel strain ST709, which belongs to the clonal complex of the predominant ST4 in China. The novel integron containing blaIMP-1 featured the oxacillinase-101 gene, which is a previously unreported structure, with an IncN4 plasmid type. However, integrons found in the strains possessing blaIMP-6, which were the most commonly identified, matched those reported domestically in Klebsiella pneumoniae, suggesting the prevalence of identical integrons. Transposons containing blaNDM are similar or identical to the transposon structure of K. aerogenes harboring blaNDM-5 previously reported in Japan, suggesting that the same type of transposon could have been transmitted to K. aerogenes in Japan. This investigation analyzed mobile genetic elements, such as integrons and transposons, to understand the spread of carbapenemases, highlighting the growing challenge of carbapenem-resistant Enterobacterales in Japan and underscoring the critical need for ongoing surveillance to control these pathogens.


Assuntos
Carbapenêmicos , Enterobacter aerogenes , Infecções por Klebsiella , Epidemiologia Molecular , beta-Lactamases , Japão/epidemiologia , Carbapenêmicos/farmacologia , beta-Lactamases/genética , Humanos , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Enterobacter aerogenes/genética , Enterobacter aerogenes/efeitos dos fármacos , Proteínas de Bactérias/genética , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Integrons/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Plasmídeos/genética , Sequenciamento Completo do Genoma , Elementos de DNA Transponíveis/genética
4.
Pathogens ; 12(10)2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37887763

RESUMO

In Japan, nationwide epidemiological surveys on carbapenem-resistant Enterobacterales (CREs), including comprehensive information, are scarce, with most data available only through public reports. This study analyzed data on the Enterobacterales family collected from nationwide testing centers between January 2016 and December 2022, focusing on isolates that met the criteria for CRE in Japan based on drug susceptibility. We investigated 5,323,875 Enterobacterales isolates of 12 different species; among 4696 (0.09%) CRE strains, the proportion of major CRE isolates was as follows: Escherichia coli, 31.3%; Klebsiella pneumoniae, 28.0%; Enterobacter cloacae, 18.5%; and Klebsiella aerogenes, 6.7%. Moreover, over a 7-year period, Providencia rettgeri, E. cloacae, K. aerogenes, and K. pneumoniae demonstrated relatively high CRE percentages of 0.6% (156/26,185), 0.47% (869/184,221), 0.28% (313/110,371), and 0.17% (1314/780,958), respectively. The number of CRE strains isolated from different samples was as follows: urine, 2390; respiratory specimens, 1254; stool, 425; blood, 252; others, 375. In the broader context, including colonization, the predominant isolates of CREs collected at nationwide testing centers are E. coli and K. pneumoniae. Furthermore, recently, attention has been directed toward less common CRE species, such as Klebsiella oxytoca and Providencia rettgeri, and thus, it might be necessary to continue monitoring these less common species.

5.
Nat Commun ; 14(1): 4478, 2023 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-37542032

RESUMO

Biological rhythms are involved in almost all types of biological processes, not only physiological processes but also morphogenesis. Currently, how periodic morphological patterns of tissues/organs in multicellular organisms form is not fully understood. Here, using mouse zigzag hair, which has 3 bends, we found that a change in the combination of hair progenitors and their micro-niche and subsequent bend formation occur every three days. Chimeric loss-of-function and gain-of-function of Ptn and Aff3, which are upregulated immediately before bend formation, resulted in defects in the downward movement of the micro-niche and the rhythm of bend formation in an in vivo hair reconstitution assay. Our study demonstrates the periodic change in the combination between progenitors and micro-niche, which is vital for the unique infradian rhythm.


Assuntos
Ritmo Infradiano , Camundongos , Animais , Cabelo , Periodicidade , Folículo Piloso
6.
Cancer Sci ; 114(9): 3687-3697, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37364599

RESUMO

Langerhans cell histiocytosis (LCH) is a rare disease characterized by clonal expansion of CD1a+ CD207+ myeloid dendritic cells. The features of LCH are mainly described in children and remain poorly defined in adults; therefore, we conducted a nationwide survey to collect clinical data from 148 adult patients with LCH. The median age at diagnosis was 46.5 (range: 20-87) years with male predominance (60.8%). Among the 86 patients with detailed treatment information, 40 (46.5%) had single system LCH, whereas 46 (53.5%) had multisystem LCH. Moreover, 19 patients (22.1%) had an additional malignancy. BRAF V600E in plasma cell-free DNA was associated with a low overall survival (OS) rate and the risk of the pituitary gland and central nervous system involvement. At a median follow-up of 55 months from diagnosis, six patients (7.0%) had died, and the four patients with LCH-related death did not respond to initial chemotherapy. The OS probability at 5 years post-diagnosis was 90.6% (95% confidence interval: 79.8-95.8). Multivariate analysis showed that patients aged ≥60 years at diagnosis had a relatively poor prognosis. The probability of event-free survival at 5 years was 52.1% (95% confidence interval: 36.6-65.5), with 57 patients requiring chemotherapy. In this study, we first revealed the high rate of relapse after chemotherapy and mortality of poor responders in adults as well as children. Therefore, prospective therapeutic studies of adults with LCH using targeted therapies are needed to improve outcomes in adults with LCH.


Assuntos
Histiocitose de Células de Langerhans , Neoplasias , Criança , Humanos , Masculino , Adulto , Adulto Jovem , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Feminino , Prognóstico , Proteínas Proto-Oncogênicas B-raf/genética , Histiocitose de Células de Langerhans/diagnóstico , Histiocitose de Células de Langerhans/terapia , Intervalo Livre de Progressão , Mutação
7.
J Vet Med Sci ; 85(4): 463-470, 2023 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-36878553

RESUMO

Understanding the antimicrobial resistance of Campylobacter jejuni and Salmonella spp. isolated from patients with enteritis will aid in therapeutic decision-making. This study aimed to characterize C. jejuni and Salmonella spp. isolates from patients with enteritis. For C. jejuni, the resistance rates against ampicillin, tetracycline, and ciprofloxacin were 17.2%, 23.8%, and 46.4%, respectively. All the C. jejuni isolates were susceptible to erythromycin, which is recommended as a first-choice antimicrobial if Campylobacter enteritis is strongly suspected. C. jejuni was classified into 64 sequence types (STs), and the five major STs were ST22, ST354, ST21, ST918, and ST50. The ciprofloxacin-resistance rate of ST22 was 85.7%. For Salmonella, the resistance rates against ampicillin, cefotaxime, streptomycin, kanamycin, tetracycline, and nalidixic acid were 14.7%, 2.0%, 57.8%, 10.8%, 16.7%, and 11.8%, respectively. All the Salmonella spp. isolates were susceptible to ciprofloxacin. Therefore, fluoroquinolones are the recommended antimicrobials against Salmonella enteritis. S. Thompson, S. Enteritidis, and S. Schwarzengrund were the three most prevalent serotypes. The two cefotaxime-resistant isolates were serotyped as S. Typhimurium and were found to harbor blaCMY-2. The results of this study would help select antimicrobials for treating patients with Campylobacter and Salmonella enteritis.


Assuntos
Anti-Infecciosos , Infecções por Campylobacter , Campylobacter jejuni , Enterite , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Japão/epidemiologia , Farmacorresistência Bacteriana , Ciprofloxacina/farmacologia , Tetraciclina/uso terapêutico , Infecções por Campylobacter/tratamento farmacológico , Infecções por Campylobacter/epidemiologia , Infecções por Campylobacter/veterinária , Salmonella , Enterite/epidemiologia , Enterite/veterinária , Anti-Infecciosos/uso terapêutico , Ampicilina/uso terapêutico , Cefotaxima/uso terapêutico , Testes de Sensibilidade Microbiana/veterinária
9.
Cancers (Basel) ; 15(4)2023 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36831459

RESUMO

BACKGROUND: To treat diseases caused by genetic variants, it is necessary to identify disease-causing variants in patients. However, since there are a large number of disease-causing variants, the application of AI is required. We propose AI to solve this problem and report the results of its application in identifying disease-causing variants. METHODS: To assist physicians in their task of identifying disease-causing variants, we propose an explainable AI (XAI) that combines high estimation accuracy with explainability using a knowledge graph. We integrated databases for genomic medicine and constructed a large knowledge graph that was used to achieve the XAI. RESULTS: We compared our XAI with random forests and decision trees. CONCLUSION: We propose an XAI that uses knowledge graphs for explanation. The proposed method achieves high estimation performance and explainability. This will support the promotion of genomic medicine.

11.
Cancers (Basel) ; 16(1)2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38201563

RESUMO

This study aimed to comprehensively clarify the genomic landscape and its association with tumor mutational burden-high (TMB-H, ≥10 mut/Mb) and microsatellite instability-high (MSI-H) in endometrial, cervical, and ovarian cancers. We obtained genomic datasets of a comprehensive genomic profiling test, FoundationOne® CDx, with clinical information using the "Center for Cancer Genomics and Advanced Therapeutics" (C-CAT) database in Japan. Patients can undergo the tests only after standardized treatments under universal health insurance coverage. Endometrial cancers were characterized by a high frequency of TMB-H and MSI-H, especially in endometrioid carcinomas. The lower ratio of POLE exonuclease mutations and the higher ratio of TP53 mutations compared to previous reports suggested the prognostic effects of the molecular subtypes. Among the 839 cervical cancer samples, frequent mutations of KRAS, TP53, PIK3CA, STK11, CDKN2A, and ERBB2 were observed in adenocarcinomas, whereas the ratio of TMB-H was significantly higher in squamous cell carcinomas. Among the 1606 ovarian cancer samples, genomic profiling of serous, clear cell, endometrioid, and mucinous carcinomas was characterized. Pathogenic mutations in the POLE exonuclease domain were associated with high TMB, and the mutation ratio was low in both cervical and ovarian cancers. The C-CAT database is useful for determining the mutational landscape of each cancer type and histological subtype. As the dataset is exclusively collected from patients after the standardized treatments, the information on "druggable" alterations highlights the unmet needs for drug development in major gynecological cancers.

12.
Nat Cell Biol ; 24(11): 1595-1605, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36253535

RESUMO

Salivary glands act as virus reservoirs in various infectious diseases and have been reported to be targeted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the mechanisms underlying infection and replication in salivary glands are still enigmatic due to the lack of proper in vitro models. Here, we show that human induced salivary glands (hiSGs) generated from human induced pluripotent stem cells can be infected with SARS-CoV-2. The hiSGs exhibit properties similar to those of embryonic salivary glands and are a valuable tool for the functional analysis of genes during development. Orthotopically transplanted hiSGs can be engrafted at a recipient site in mice and show a mature phenotype. In addition, we confirm SARS-CoV-2 infection and replication in hiSGs. SARS-CoV-2 derived from saliva in asymptomatic individuals may participate in the spread of the virus. hiSGs may be a promising model for investigating the role of salivary glands as a virus reservoir.


Assuntos
COVID-19 , Células-Tronco Pluripotentes Induzidas , Humanos , Animais , Camundongos , SARS-CoV-2 , Organoides , Glândulas Salivares
13.
Microbiol Spectr ; 10(4): e0120422, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-35862988

RESUMO

Although the prevalence of carbapenem-resistant Enterobacterales remains low in Japan, these bacteria are a growing problem worldwide, owing to their multidrug resistance phenotype. We isolated a multidrug-resistant Providencia rettgeri strain, NR1418, harboring a rare blaIMP variant, blaIMP-70, a novel blaCTX-M variant, designated blaCTX-M-253, and blaMOX-1. This strain is resistant to ß-lactams, amikacin, levofloxacin, and colistin. Genomic analysis revealed that NR1418 carries two plasmids, designated pNR1418-1 and pNR1418-2. The pNR1418-1 plasmid harbors blaCTX-M-253, blaTEM-1, and blaMOX-1, while the pNR1418-2 plasmid harbors blaIMP-70, which is located in a class 1 integron. Both plasmids exhibit high similarities with the plasmid of the P. rettgeri isolate BML2526, which also harbors blaIMP-70 and was identified in the same region of Japan as NR1418 at a different point in time. This indicates the possibility of the emergence and evolution of IMP-70-producing P. rettgeri and suggests that the plasmid of BML2526 may have occurred following recombination of the two plasmids harbored by NR1418. Further, blaIMP-70 and blaCTX-M-253 were found on unique plasmids, indicating that they likely evolved through mutations and recombination. IMPORTANCE Although Providencia rettgeri is an opportunistic pathogen, its intrinsic resistance to colistin and tigecycline makes the treatment of carbapenem-resistant P. rettgeri challenging. We isolated a multidrug-resistant P. rettgeri strain which harbored a rare blaIMP variant, blaIMP-70, a novel blaCTX-M variant, blaCTX-M-253, and blaMOX-1 from a urinary sample obtained in Osaka, Japan. We investigated its genetic structure and evaluated the evolution of the plasmids carrying these genes. We show that blaIMP-70, blaCTX-M-253, and blaMOX-1 are present on unique plasmids and that they have high similarities to the plasmid of another IMP-70-producing P. rettgeri isolate that was identified as being from the same location. The evolution of plasmids through mutations and recombination may play a role in the development and spread of multidrug resistance.


Assuntos
beta-Lactamases , Antibacterianos/farmacologia , beta-Lactamases/genética , Carbapenêmicos , Colistina , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Providencia
14.
Microbiol Spectr ; 10(2): e0249121, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35389240

RESUMO

The genus Pseudomonas, a complex Gram-negative genus, includes species isolated from various environments, plants, animals, and humans. We compared whole-genome sequencing (WGS) with clinical bacteriological methods and evaluated matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to identify Pseudomonas species. Clinical isolates (N = 42) identified as P. putida or P. fluorescens by a bacterial identification system based on biochemical properties were reexamined by another identification system based on biochemical properties, two systems based on MALDI-TOF MS, and WGS. WGS revealed that 30 of the 42 isolates belonged to one of 14 known Pseudomonas species, respectively. The remaining 12 belonged to one of 9 proposed novel Pseudomonas species, respectively. MALDI-TOF MS analysis showed that the 9 novel species had unique major peaks. These results suggest that WGS is the optimal method to identify Pseudomonas species and that MALDI-TOF MS may complement WGS in identification. Based on their morphologic, physiologic, and biochemical properties, we propose nine novel Pseudomonas species. IMPORTANCE Most of the clinical isolates, identified as P. putida or P. fluorescens, were misidentified in clinical laboratories. Whole-genome sequencing (WGS) revealed that these isolates belonged to different Pseudomonas species, including novel species. WGS is a gold-standard method to identify Pseudomonas species, and MALDI-TOF MS analysis has the potential to complement WGS to reliably identify them.


Assuntos
Pseudomonas fluorescens , Pseudomonas putida , Animais , Técnicas Bacteriológicas/métodos , Pseudomonas fluorescens/genética , Pseudomonas putida/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Sequenciamento Completo do Genoma
16.
Jpn J Infect Dis ; 75(1): 41-48, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-34193664

RESUMO

The Enterobacter cloacae complex (ECC) is one of the most common causes of bacteremia and leads to poor clinical outcomes. The aim of this study was to clarify the antimicrobial susceptibility profiles and genetic backgrounds of non-carbapenemase-producing reduced-carbapenem-susceptible (RCS) ECC blood isolates in Japan using agar dilution antimicrobial susceptibility testing, whole-genome sequencing, and quantitative polymerase chain reaction for ampC, ompC, and ompF transcripts. Forty-two ECC blood isolates were categorized into RCS and carbapenem-susceptible groups based on the minimum inhibitory concentration of imipenem. The RCS ECC blood isolates belonged to distinct species and sequence types and produced varying class C ß-lactamases. The E. roggenkampii, E. asburiae, and E. bugandensis isolates belonged only to the RCS group. Some E. hormaechei ssp. steigerwaltii isolates from the RCS group exhibited AmpC overexpression caused by amino acid substitutions in AmpD and AmpR along with ompF downregulation. These findings suggest that non-carbapenemase-producing RCS ECC blood isolates are genetically diverse.


Assuntos
Carbapenêmicos , Infecções por Enterobacteriaceae , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Hemocultura , Carbapenêmicos/farmacologia , Enterobacter cloacae/genética , Infecções por Enterobacteriaceae/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , beta-Lactamases/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-34494947

RESUMO

Three Gram-positive bacterial strains, BML-BC004, BML-BC017 and BML-BC059, isolated from blood samples from three inpatients in Japan, were identified as members of Bacillus cereus using matrix-assisted laser desorption ionization time-of-flight MS. The 16S rRNA gene sequences of these three strains were more than 97.1 % similar to 18 type strains belonging to the B. cereus group. Whole-genome comparisons, using average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), confirmed that the three strains represented three individual distinct species belonging to the B. cereus group. A phylogenetic tree showed that BML-BC004, BML-BC017 and BML-BC059 were located close to B. luti, B. mobilis and B. paramycoides, respectively. Based on these phylogenetic and phenotypic data, including values below the threshold for ANI and dDDH, the three strains should be classified as representing three different novel species of the B. cereus group: Bacillus sanguinis sp. nov., with type strain BML-BC004T (=DSM 111102T=JCM 34122T), Bacillus paramobilis sp. nov., with type strain BML-BC017T (=DSM 111100T=JCM 34124T) and Bacillus hominis sp. nov., with type strain BML-BC059T (=DSM 111101T=JCM 34125T).


Assuntos
Bacillus cereus/classificação , Sangue/microbiologia , Filogenia , Bacillus cereus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Humanos , Japão , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
18.
Cancers (Basel) ; 13(9)2021 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-33923024

RESUMO

With the recent advances in noninvasive approaches for cancer diagnosis and surveillance, the term "liquid biopsy" has become more familiar to clinicians, including hematologists. Liquid biopsy provides a variety of clinically useful genetic data. In this era of personalized medicine, genetic information is critical to early diagnosis, aiding risk stratification, directing therapeutic options, and monitoring disease relapse. The validity of circulating tumor DNA (ctDNA)-mediated liquid biopsies has received increasing attention. This review summarizes the current knowledge of liquid biopsy ctDNA in hematological malignancies, focusing on the feasibility, limitations, and key areas of clinical application. We also highlight recent advances in the minimal residual disease monitoring of leukemia using ctDNA. This article will be useful to those involved in the clinical practice of hematopoietic oncology.

19.
Sci Rep ; 11(1): 1173, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33568688

RESUMO

In mammals, organ induction occurs only during embryonic development except for hair follicles (HFs). However, HF-resident epithelial stem cells (HFSCs), which are responsible for repetitive HF regeneration, are not fully characterized. Here, we establish in vitro culture systems that are capable of controlling the ability of HFSCs to regenerate HFs. Based on a method that precisely controlled the number of HFs for regeneration, functional analysis revealed that CD34/CD49f/integrin ß5 (Itgß5)-triple-positive (CD34+/CD49f+/Itgß5+) cells have multipotency and functional significance for continual hair regeneration. In native HFs, these cells reside in the uppermost area of the bulge region, which is surrounded by tenascin in mice and humans. This study unveils the subpopulation of HFSCs responsible for long-term hair cycling of HFs regenerated from bioengineered HF germ, suggesting the presence of functional heterogeneity among bulge HFSCs and the utility of our culture system to achieve HF regenerative therapy.


Assuntos
Células Epiteliais/metabolismo , Folículo Piloso/fisiologia , Células-Tronco Multipotentes/metabolismo , Regeneração , Animais , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Camundongos Transgênicos
20.
Front Microbiol ; 12: 794134, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35095805

RESUMO

Various carbapenemases have been identified in the Enterobacteriaceae. However, the induction and corresponding regulator genes of carbapenemase NmcA has rarely been detected in the Enterobacter cloacae complex (ECC). The NmcA-positive isolate ECC NR1491 was first detected in Japan in 2013. It was characterized and its induction system elucidated by evaluating its associated regulator genes nmcR, ampD, and ampR. The isolate was highly resistant to all ß-lactams except for third generation cephalosporins (3GC). Whole-genome analysis revealed that bla NmcA was located on a novel 29-kb putatively mobile element called EludIMEX-1 inserted into the chromosome. The inducibility of ß-lactamase activity by various agents was evaluated. Cefoxitin was confirmed as a strong concentration-independent ß-lactamase inducer. In contrast, carbapenems induced ß-lactamase in a concentration-dependent manner. All selected 3GC-mutants harboring substitutions on ampD (as ampR and nmcR were unchanged) were highly resistant to 3GC. The ampD mutant strain NR3901 presented with a 700 × increase in ß-lactamase activity with or without induction. Similar upregulation was also observed for ampC and nmcA. NR1491 (pKU412) was obtained by transforming the ampR mutant (135Asn) clone plasmid whose expression increased by ∼100×. Like NR3901, it was highly resistant to 3GC. Overexpression of ampC, rather than nmcA, may have accounted for the higher MIC in NR1491. The ampR mutant repressed nmcA despite induction and it remains unclear how it stimulates nmcA transcription via induction. Future experiments should analyze the roles of nmcR mutant strains.

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