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1.
Vaccines (Basel) ; 12(6)2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38932320

RESUMO

The COVID-19 pandemic necessitated an urgent global response in vaccine deployment, achieving over 70.6% global vaccination coverage with at least one dose. This study focuses on Taiwan's vaccine administration and adverse event reporting, set against a global backdrop. Using data from Taiwan's Vaccine Adverse Event Reporting System (VAERS) and global vaccination data, this study investigates vaccine safety and the public health implications of vaccination strategies from local and global perspectives. Taiwan's proactive approach, resulting in high vaccination rates, provides a case study for the monitoring and management of vaccine-related adverse events. This study offers insights into the safety profiles of various COVID-19 vaccines and further explores the implications of adverse event reporting rates for vaccine policy and public health strategies. The comparative analysis reveals that, while vaccination has been effective in controlling the virus's spread, safety monitoring remains critical for maintaining public trust. It underscores the necessity of enhanced surveillance and the importance of transparent and tailored risk communication to support informed public health decisions. The findings aim to contribute to the global dialogue on vaccine safety, equitable distribution, evidence-based policy-making, and development of mitigation measures with consideration of local demographics in the ongoing fight against COVID-19.

2.
Healthcare (Basel) ; 12(4)2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38391863

RESUMO

AIM: The first coronavirus disease 2019 (COVID-19) outbreak in Taiwan occurred in May 2021 and many individuals were infected. All COVID-19 patients were quarantined in designated facilities until they fully recovered to prevent the spread of the disease. Prolonged quarantine could adversely affect these patients. In this study, we focused on investigating changes in the quality of life and mental health of individuals discharged from hospital after recovering from COVID-19. METHODS: This study employed a longitudinal design and surveyed individuals discharged from a teaching hospital in northern Taiwan in 2021 within one week of their discharge and again after one month. An online questionnaire comprising the participants' background, respiratory function (COPD Assessment Test), quality of life (WHOQoL-BREF), and emotional problems (DASS-21) was administered to the participants. RESULTS: A total of 56 participants actively took part in both surveys. We observed that participants with abnormal respiratory function had a lower physical and psychological quality of life, especially those with severe symptoms requiring endotracheal intubation during the treatment period of COVID-19. Additionally, approximately 30% of participants experienced anxiety problems throughout this study period. Finally, patients with COVID-19 symptoms exhibited a lower quality of life and higher levels of severe emotional problems. CONCLUSIONS: According to our findings, it is necessary to monitor and provide appropriate interventions for individuals who have recovered from COVID-19, especially those who experienced severe symptoms that required endotracheal intubation during COVID-19 treatment. These interventions, such as symptom management and psychological support, can help improve their quality of life and reduce emotional problems. Therefore, after the participants are discharged, hospitals should regularly track the patients' status and provide appropriate support or referrals to help these individuals. Otherwise, future research could include more participants and follow up with them for longer to investigate the longitudinal impact of COVID-19.

3.
Thorax ; 78(5): 504-514, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-35450943

RESUMO

RATIONALE: Acute respiratory distress syndrome (ARDS) is a lethal complication of severe bacterial pneumonia due to the inability to dampen overexuberant immune responses without compromising pathogen clearance. Both of these processes involve tissue-resident and bone marrow (BM)-recruited macrophage (MΦ) populations which can be polarised to have divergent functions. Surprisingly, despite the known immunomodulatory properties of mesenchymal stem cells (MSCs), simultaneous interactions with tissue-resident and recruited BMMΦ populations are largely unexplored. OBJECTIVES: We assessed the therapeutic use of human placental MSCs (PMSCs) in severe bacterial pneumonia with elucidation of the roles of resident alveolar MΦs (AMΦs) and BMMΦs. METHODS: We developed a lethal, murine pneumonia model using intratracheal infection of a clinically relevant Klebsiella pneumoniae (KP) strain with subsequent intravenous human PMSC treatment. Pulmonary AMΦ and recruited BMMΦ analyses, histological evaluation, bacterial clearance and mice survival were assessed. To elucidate the role of resident AMΦs in improving outcome, we performed AMΦ depletion in the KP-pneumonia model with intratracheal clodronate pretreatment. MEASUREMENTS AND MAIN RESULTS: Human PMSC treatment decreased tissue injury and improved survival of severe KP-pneumonia mice by decreasing the presence and function of recruited M1 BMMΦ while preserving M2 AMΦs and enhancing their antibacterial functions. Interestingly, PMSC therapy failed to rescue AMΦ-depleted mice with KP pneumonia, and PMSC-secreted IL-1ß was identified as critical in increasing AMΦ antibacterial activities to significantly improve pathogen clearance-especially bacteraemia-and survival. CONCLUSIONS: Human PMSC treatment preferentially rescued resident M2 AMΦs over recruited M1 BMMΦs with overall M2 polarisation to improve KP-related ARDS survival.


Assuntos
Células-Tronco Mesenquimais , Pneumonia Bacteriana , Síndrome do Desconforto Respiratório , Feminino , Humanos , Camundongos , Animais , Gravidez , Medula Óssea , Klebsiella , Placenta , Macrófagos , Pneumonia Bacteriana/terapia , Pneumonia Bacteriana/microbiologia , Síndrome do Desconforto Respiratório/terapia , Klebsiella pneumoniae , Macrófagos Alveolares
4.
Taiwan J Obstet Gynecol ; 61(5): 868-872, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36088058

RESUMO

OBJECTIVE: The pandemic Coronavirus Disease 2019 (COVID-19) is a global public health crisis. Many maternity units worldwide are currently establishing the management protocols for these patients. CASE REPORT: We report the first critically ill pregnant woman with COVID-19-induced respiratory failure undergoing emergent caesarean delivery at 32 weeks of gestation, in the setting of a positive pressure operating room (OR) with negative pressure anteroom in Taiwan. CONCLUSION: Multidisciplinary planning and collaboration are necessary to achieve satisfactory clinical outcomes in pregnancies with critical COVID-19 pneumonia. The combinations of comprehensive evaluation, timely treatment as well as establishment of rigorous protocol and safe environment for the emergent delivery are important.


Assuntos
COVID-19 , Pneumonia , COVID-19/complicações , Cesárea , Feminino , Humanos , Recém-Nascido , Gravidez , Gestantes , Taiwan
6.
Antioxidants (Basel) ; 10(9)2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34573071

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic continues to burden healthcare systems worldwide. COVID-19 symptoms are highly heterogeneous, and the patient may be asymptomatic or may present with mild to severe or fatal symptoms. Factors, such as age, sex, and comorbidities, are key determinants of illness severity and progression. Aging is accompanied by multiple deficiencies in interferon production by dendritic cells or macrophages in response to viral infections, resulting in dysregulation of inflammatory immune responses and excess oxidative stress. Age-related dysregulation of immune function may cause a more obvious pathophysiological response to SARS-CoV-2 infection in elderly patients and may accelerate the risk of biological aging, even after recovery. For more favorable treatment outcomes, inhibiting viral replication and dampening inflammatory and oxidative responses before induction of an overt cytokine storm is crucial. Resveratrol is a potent antioxidant with antiviral activity. Herein, we describe the reasons for impaired interferon production, owing to aging, and the impact of aging on innate and adaptive immune responses to infection, which leads to inflammation distress and immunosuppression, thereby causing fulminant disease. Additionally, the molecular mechanism by which resveratrol could reverse a state of excessive basal inflammatory and oxidative stress and low antiviral immunity is discussed.

8.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445700

RESUMO

Severe acute respiratory syndrome coronavirus 2 is a new, highly pathogenic virus that has recently elicited a global pandemic called the 2019 coronavirus disease (COVID-19). COVID-19 is characterized by significant immune dysfunction, which is caused by strong but unregulated innate immunity with depressed adaptive immunity. Reduced and delayed responses to interferons (IFN-I/IFN-III) can increase the synthesis of proinflammatory cytokines and extensive immune cell infiltration into the airways, leading to pulmonary disease. The development of effective treatments for severe COVID-19 patients relies on our knowledge of the pathophysiological components of this imbalanced innate immune response. Strategies to address innate response factors will be essential. Significant efforts are currently underway to develop vaccines against SARS-CoV-2. COVID-19 vaccines, such as inactivated DNA, mRNA, and protein subunit vaccines, have already been applied in clinical use. Various vaccines display different levels of effectiveness, and it is important to continue to optimize and update their composition in order to increase their effectiveness. However, due to the continuous emergence of variant viruses, improving the immunity of the general public may also increase the effectiveness of the vaccines. Many observational studies have demonstrated that serum levels of vitamin D are inversely correlated with the incidence or severity of COVID-19. Extensive evidence has shown that vitamin D supplementation could be vital in mitigating the progression of COVID-19 to reduce its severity. Vitamin D defends against SARS-CoV-2 through a complex mechanism through interactions between the modulation of innate and adaptive immune reactions, ACE2 expression, and inhibition of the renin-angiotensin system (RAS). However, it remains unclear whether Vit-D also plays an important role in the effectiveness of different COVID-19 vaccines. Based on analysis of the molecular mechanism involved, we speculated that vit-D, via various immune signaling pathways, plays a complementary role in the development of vaccine efficacy.


Assuntos
Vacinas contra COVID-19/administração & dosagem , COVID-19/prevenção & controle , Vitamina D/administração & dosagem , Vitamina D/sangue , Animais , COVID-19/sangue , COVID-19/imunologia , Vacinas contra COVID-19/imunologia , Ensaios Clínicos como Assunto , Humanos , Imunogenicidade da Vacina , Pandemias/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto , SARS-CoV-2/isolamento & purificação , Vitamina D/imunologia
9.
Microbiol Spectr ; 9(1): e0002221, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34259551

RESUMO

Colistin resistance due to the mcr-type genes in Escherichia coli is well characterized. In order to study the resistance mechanism in mcr-negative colistin-resistant E. coli, strains were selected from a nationwide antimicrobial resistance surveillance program in Taiwan for further investigation. A total of 11 mcr-negative colistin-resistant isolates among 7,942 (0.1%) clinical E. coli isolates were identified between 2008 and 2018. Their prevalence was low and remained stable during the study period. Since 2012, ST131 and ST1193 clones with multiple drug-resistant phenotypes have emerged. All resistant strains displayed higher expression levels of the operons pmrHFIJKLM and pmrCAB than the control MG1655 strain. Although several amino acid substitutions were identified in PmrA or PmrB, only R81H in PmrA was associated with overexpression of pmrHFIJKLM and colistin resistance. The effect of substitution R81H in PmrA in colistin resistance was confirmed by complementation experiments. Although some strains harbored substitutions in PmrB, the identified mutations in pmrB did not contribute to colistin resistance. In conclusion, the amino acid substitution R81H in PmrA is an independent factor contributing to colistin resistance in non-mcr E. coli. IMPORTANCE The molecular epidemiology and resistance mechanisms of mcr-negative colistin-resistant E. coli are not well described. In this study, a total of 11 mcr-negative colistin-resistant E. coli isolates were selected from a nationwide antimicrobial resistance surveillance program in Taiwan for further investigation. We determined the resistance mechanism of non-mcr colistin-resistant strains using gene knockout and complementation experiments. We observed the occurrence of the global multiple-drug-resistant E. coli clones ST131 and ST1193 starting in 2012. Moreover, for the first time, we proved that the amino acid substitution R81H in PmrA is an independent factor contributing to colistin resistance in non-mcr E. coli. The study results helped to gain an insight into the diversity and complexity of chromosome-encoded colistin resistance in E. coli.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Colistina/farmacologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana , Escherichia coli/classificação , Escherichia coli/isolamento & purificação , Humanos , Testes de Sensibilidade Microbiana , Mutação de Sentido Incorreto , Filogenia , Taiwan
10.
STAR Protoc ; 2(1): 100337, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33644772

RESUMO

Hypervirulent Klebsiella pneumoniae (hvKP) strains cause extra-pulmonary infections such as intra-abdominal infection (IAI) even in healthy individuals due to its resistance to polymorphonuclear neutrophil (PMN) killing and a high incidence of multidrug resistance. To assess whether human placental mesenchymal stem cell (PMSC) therapy can be an effective treatment option, we established a murine model of hvKP-IAI to evaluate immune cell modulation and bacterial clearance for this highly lethal infection. This protocol can rapidly assess potential therapies for severe bacterial IAIs. For complete details on the use and execution of this protocol, please refer to Wang et al. (2020).


Assuntos
Infecções por Klebsiella , Klebsiella pneumoniae/imunologia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/imunologia , Animais , Feminino , Xenoenxertos , Humanos , Infecções por Klebsiella/imunologia , Infecções por Klebsiella/terapia , Camundongos , Placenta , Gravidez
11.
Infect Drug Resist ; 14: 971-977, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33737819

RESUMO

The COVID-19 pandemic has caused a global public health crisis. Taiwan experienced two waves of imported cases of coronavirus disease 2019 (COVID-19), first from China in January to late February, 2020 then from other countries starting in early March. As of Dec 14, 2020, 733 cases have been reported in Taiwan, with cases of entire families being infected. This study aimed to investigate the clinical characteristics and differentiation of genetic variation among isolates from a cluster of familial COVID-19 infection. The parents had pneumonia (Case 14, father, and Case 15, mother), the elder son (Case 17) had mild cough, and the younger son (Case 18) was asymptomatic. In this study, four full viral genomes were sequenced by Illumina sequencing directly from specimens. Phylogenetic tree analysis revealed that these sequences came from Italy, not China, indicating that no major strain has been circulating in Taiwan. Several novel mutations were observed in the asymptomatic patient, such as nsp2, nsp12, and nsp14. These mutations may be associated with the severity of COVID-19 infection.

12.
Emerg Microbes Infect ; 10(1): 161-166, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33410371

RESUMO

SARS-CoV-2 has spread rapidly, causing deaths worldwide. In this study, we evaluated the performance of the BD MAX Open System module for identifying viral pathogens, including SARS-CoV-2, in nasopharyngeal specimens from individuals with symptoms of upper respiratory tract infection. We developed and validated a rapid total nucleic acid extraction method based on real-time reverse transcription-polymerase chain reaction (RT-PCR) for the reliable, high-throughput simultaneous detection of common cold viral pathogens using the BD MAX Platform. The system was evaluated using 205 nasopharyngeal swab clinical samples. For assessment of the limit of detection (LoD), we used SARS-CoV-2, influenza A/B, and respiratory syncytial virus (RSV) RNA standards. The BD MAX dual multiplex real-time RT-PCR panel demonstrated a sensitivity comparable to that of the World Health Organization-recommended SARS-CoV-2 assay with an LoD of 50 copies/PCR. The LoD of influenza A/B and RSV was 100-200 copies/PCR. The overall percent agreement between the BD MAX panel and laboratory-developed RT-PCR test on 55 SARS-CoV-2-positive clinical samples was 100%. Among the 55 positive cases of COVID-19 analysed, no coinfection was detected. The BD MAX rapid multiplex PCR provides a highly sensitive, robust, and accurate assay for the rapid detection of SARS-CoV-2, influenza A/B, and RSV.


Assuntos
COVID-19/diagnóstico , Influenza Humana/diagnóstico , Reação em Cadeia da Polimerase/métodos , Infecções por Vírus Respiratório Sincicial/diagnóstico , SARS-CoV-2/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Teste para COVID-19 , Coinfecção/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Adulto Jovem
13.
Clin Chim Acta ; 514: 54-58, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33316217

RESUMO

BACKGROUND AND AIMS: Immediate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for preventing the spread of coronavirus disease 2019 (COVID-19). The LabTurbo AIO 48 system is an automated platform that allows nucleic acid extraction and sample analysis on the same instrument, producing faster results without affecting their accuracy. We aimed to independently evaluate the LabTurbo AIO 48 (all-in-one system) for SARS-CoV-2 detection. MATERIALS AND METHODS: Comparative limit of detection (LOD) was assessed on both the LabTurbo AIO 48 and current standard detection system based on real-time reverse transcriptase polymerase chain reaction (RT-PCR), using SARS-CoV-2 RNA control. Additional 125 primary clinical samples were assessed using both the protocols in parallel. RESULTS: The turnaround time from sample to results for 48 samples analyzed on LabTurbo AIO 48 was approximately 2.5 h, whereas that analyzed using the in-house RT-PCR protocol was 4.8 h. LabTurbo AIO 48 also demonstrated higher sensitivity than our reference RT-PCR assay, with a LOD of 9.4 copies/reaction. The overall percentage agreement between both the methods for 125 samples was 100%. CONCLUSION: LabTurbo AIO 48 is a robust detection option for SARS-CoV-2, allowing faster results and, consequently, aiding in better control and prevention of COVID-19.


Assuntos
Teste para COVID-19/métodos , Ensaios de Triagem em Larga Escala/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , COVID-19/diagnóstico , Humanos , Limite de Detecção , RNA Viral/química , Padrões de Referência , Sensibilidade e Especificidade , Carga Viral
14.
Cell Rep ; 32(13): 108188, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32997996

RESUMO

Hypervirulent Klebsiella pneumoniae (hvKP) causes severe infections even in healthy individuals by escaping surveillance and killing from polymorphonuclear neutrophils (PMNs), the first-line leukocytes in bacterial infections; moreover, the emergence of multidrug-resistant strains further limits treatment options. We therefore assess whether multilineage mesenchymal stem cells (MSCs), best known for immunomodulation toward T cells, could be therapeutic for highly virulent bacterial infections via modulation of PMNs. We find that both bone marrow MSCs and placental MSCs (PMSCs) preserve in vitro PMN survival, but only PMSCs significantly enhance multiple PMN bactericidal functions, including phagocytosis, through secretion of interleukin-1ß (IL-1ß). PMSC treatment of hvKP-infected mice suppresses T and natural killer (NK) cell responses as expected but can preferentially recruit PMNs and enhance antibacterial functions to allow for disease survival; IL-1ß knockdown in PMSCs significantly decreases hvKP clearance, worsening survival and resulting in 100% lethality. Our data strongly implicate the possible use of PMSCs for infections of PMN-resistant hvKP strains.


Assuntos
Interleucina-1beta/metabolismo , Infecções por Klebsiella/genética , Células-Tronco Mesenquimais/metabolismo , Neutrófilos/metabolismo , Feminino , Humanos , Placenta , Gravidez
15.
PeerJ ; 8: e9318, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32596046

RESUMO

Coronavirus disease 2019 has become a worldwide pandemic. By April 7, 2020, approximately 1,279,722 confirmed cases were reported worldwide including those in Asia, European Region, African Region and Region of the Americas. Rapid and accurate detection of Severe Acute Respiratory Syndrome Virus 2 (SARS-CoV-2) is critical for patient care and implementing public health measures to control the spread of infection. In this study, we developed and validated a rapid total nucleic acid extraction method based on real-time RT-PCR for reliable, high-throughput identification of SARS-CoV-2 using the BD MAX platform. For clinical validation, 300 throat swab and 100 sputum clinical samples were examined by both the BD MAX platform and in-house real-time RT-PCR methods, which showed 100% concordant results. This BD MAX protocol is fully automated and the turnaround time from sample to results is approximately 2.5 h for 24 samples compared to 4.8 h by in-house real-time RT-PCR. Our developed BD MAX RT-PCR assay can accurately identify SARS-CoV-2 infection and shorten the turnaround time to increase the effectiveness of control and prevention measures for this emerging infectious disease.

17.
Artigo em Inglês | MEDLINE | ID: mdl-32284375

RESUMO

We report the first clinical Escherichia coli strain EC3000 with concomitant chromosomal colistin and carbapenem resistance. A novel in-frame deletion, Δ6-11 (RPISLR), in pmrB that contributes to colistin resistance was verified using recombinant DNA techniques. Although being less fit than the wild-type (WT) strain or EC3000 revertant (chromosomal replacement of WT pmrB in EC3000), a portion of serially passaged EC3000 strains preserving colistin resistance without selective pressure raises the concern for further spread.


Assuntos
Colistina , Farmacorresistência Bacteriana , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Colistina/farmacologia , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Testes de Sensibilidade Microbiana , Deleção de Sequência/genética
18.
Sci Rep ; 8(1): 8468, 2018 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-29855588

RESUMO

Before 2011, the prevalence rates of carbapenemase-producing Klebsiella pneumoniae (CPKP) among carbapenem nonsusceptible K. pneumoniae (CnSKP) isolates were below 10% in Taiwan. The study presents the dissemination and increased antimicrobial resistance of CPKP from January 2012 to August 2015, as shown by Taiwanese multicenter surveillance. Isolates with minimum inhibitory concentrations (MICs) of >1 µg/mL for imipenem or meropenem were collected, screened for various carbapenemase genes by PCR, and tested for antimicrobial susceptibility. Among 1,457 CnSKP isolates, 1,250 were collected from medical centers. The CnSKP prevalence in medical centers increased by 1.7-fold during the study. Among all CnSKP isolates, 457 were CPKP. The CPKP rate among CnSKP increased by 1.5-fold and reached 36.8% in 2015. The CPKP nonsusceptibility rate to aztreonam, fluoroquinolones, and aminoglycosides increased yearly. Six CPKP isolates carried dual carbapenemase genes. Three Ambler classes were identified in 451 isolates with a single carbapenemase: classes A (315 blaKPC-2, 2 blaKPC-3, 28 blaKPC-17, 2 blaKPC-34), B (26 blaIMP-8, 2 blaNDM-1, 36 blaVIM-1), and D (40 blaOXA-48). The blaOXA-48 rate among CPKP increased by 6-fold over three years. Most KPC and OXA-48 producers were ST11. CnSKP was increasingly prevalent, owing to CPKP dissemination. Additionally, CPKP became more resistant during the study period.


Assuntos
Proteínas de Bactérias/genética , Klebsiella pneumoniae/enzimologia , beta-Lactamases/genética , Antibacterianos/farmacologia , Aztreonam/farmacologia , Proteínas de Bactérias/metabolismo , DNA Bacteriano/isolamento & purificação , DNA Bacteriano/metabolismo , Farmacorresistência Bacteriana/genética , Fluoroquinolonas/farmacologia , Hospitais , Humanos , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Prevalência , Taiwan/epidemiologia , beta-Lactamases/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-28533243

RESUMO

Tigecycline is regarded as a last-resort treatment for carbapenem-resistant Klebsiella pneumoniae (CRKP) infections, but increasing numbers of tigecycline-resistant K. pneumoniae isolates have been reported. The tigecycline resistance mechanisms in CRKP are undetermined. This study aimed to elucidate the mechanisms underlying tigecycline resistance in 16 tigecycline- and carbapenem-resistant K. pneumoniae (TCRKP) isolates. Mutations in tigecycline resistance determinant genes [ramR, acrR, oqxR, tet(A), tet(L), tet(X), tet(M), rpsJ] were assessed by PCR amplicon sequencing, and mutations in ramR and tet(A) exhibited high prevalences individually (81%) and in combination (63%). Eight functional ramR mutation profiles reducing tigecycline sensitivity were verified by plasmid complementation of wild-type and mutant ramR Using a site-specific mutant, the most frequent RamR mutation, A19V (60%), had no significant effect on tigecycline susceptibility or the upregulation of ramA and acrA Two tet(A) variants with double frameshift mutations, type 1 and type 2, were identified; type 2 tet(A) is novel. A parent strain transformed with a plasmid carrying type 1 or type 2 tet(A) increased the tigecycline MIC by 8-fold or 4-fold, respectively. Synergistic effects were observed in strains harboring no ramR gene and a mutated tet(A), with an 8-fold increase in the tigecycline MIC compared with that in strains harboring only mutated tet(A) being seen. Overall, mutations in the ramR and tet(A) efflux genes constituted the major tigecycline resistance mechanisms among the studied TCRKP isolates. The identification of strains exhibiting the combination of a ramR deficiency and widespread mutated tet(A) is concerning due to the possible dissemination of increased tigecycline resistance in K. pneumoniae.


Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Proteínas de Membrana Transportadoras/genética , Minociclina/análogos & derivados , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Transativadores/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Carbapenêmicos/farmacologia , Humanos , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Minociclina/uso terapêutico , Mutação/genética , Plasmídeos/genética , Resistência a Tetraciclina/genética , Tigeciclina
20.
PLoS One ; 12(4): e0175140, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28388651

RESUMO

OBJECTIVES: Tigecycline is a treatment option for infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP). Emerging tigecycline resistance in CRKP represents a growing threat. Knowledge of the clinical, microbiological, and molecular characteristics of tigecycline- and carbapenem-resistant Klebsiella pneumoniae (TCRKP) is limited. METHODS: Patients infected with TCRKP were identified from a Taiwanese national surveillance study. Clinical data were collected from medical records. We performed susceptibility tests, carbapenemase gene detection, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Furthermore, we performed quantitative real-time polymerase chain reaction (qRT-PCR) analyses to assess the expression levels of the efflux pump genes acrB and oqxB. RESULTS: We identified 16 patients infected with TCRKP, with urinary tract infection (UTI) being the most common type of infection (63%). The all-cause 30-day mortality rate was 44% in patients with TCRKP infection. Patients with a site of infection other than the urinary tract had a significantly higher mortality rate than patients with UTIs (83% vs. 20%, p = 0.035). PFGE and MLST revealed no dominant clone or sequence type. Using qRT-PCR, overexpression of both the acrB and oqxB genes was identified in seven isolates, and overexpression of the oqxB gene was observed in another seven. There was poor correlation between acrB or oqxB expression and tigecycline MICs (r = -0.038 and -0.166, respectively). CONCLUSIONS: The mortality rate in patients infected with TCRKP in this study was 44% and this is an important subset of patients. The absence of a linear relationship between efflux pump genes expression and MICs indicates that tigecycline resistance may be mediated by other factors. Continuous monitoring of tigecycline resistance among CRKP isolates and resistance mechanisms are necessary.


Assuntos
Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana/genética , Genes Bacterianos , Klebsiella pneumoniae/efeitos dos fármacos , Minociclina/análogos & derivados , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Transporte Biológico/genética , Feminino , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Masculino , Pessoa de Meia-Idade , Minociclina/farmacologia , Minociclina/uso terapêutico , Reação em Cadeia da Polimerase em Tempo Real , Tigeciclina , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia
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