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1.
Fish Shellfish Immunol ; 116: 1-11, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34174452

RESUMO

NK-lysin, an effector of natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), not only exhibits cytotoxic effect in fish cells, but also participates in the immune defense against pathogenic infection. In this study, ORF sequences of RCC-NK-lysin, WCC-NK-lysin and WR-NK-lysin were 369 bp. Tissue-specific analysis revealed that the highest expressions of RCC-NK-lysin and WCC-NK-lysin were observed in gill, while the peaked level of WR-NK-lysin mRNA was observed in spleen. A. hydrophila infection sharply increased RCC-NK-lysin, WCC-NK-lysin and WR-NK-lysin mRNA expression in liver, trunk kidney and spleen. In addition, elevated levels of NK-lysin mRNA were observed in cultured fin cell lines of red crucian carp (RCC), white crucian carp (WCC) and their hybrid offspring (WR) after Lipopolysaccharide (LPS) challenge. RCC-NK-lysin, WCC-NK-lysin and WR-NK-lysin exerted regulatory roles in inducing ROS generation, modulating mitochondrial membrane potential, decreasing fish cell viability and antagonizing survival signalings, respectively. RCC/WCC/WR-NK-lysin-overexpressing fish could up-regulate expressions of inflammatory cytokines and decrease bacterial loads in spleen. These results indicated that NK-lysin in hybrid fish contained close sequence similarity to those of its parents, possessing the capacities of cytotoxicity and immune defense against bacterial infection.


Assuntos
Aeromonas hydrophila , Carpas/imunologia , Doenças dos Peixes/imunologia , Proteínas de Peixes/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Proteolipídeos/imunologia , Nadadeiras de Animais/citologia , Animais , Carpas/genética , Sobrevivência Celular , Células Cultivadas , Quimera , Doenças dos Peixes/genética , Doenças dos Peixes/microbiologia , Proteínas de Peixes/genética , Expressão Gênica , Infecções por Bactérias Gram-Negativas/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Rim/metabolismo , Lipopolissacarídeos/farmacologia , Fígado/metabolismo , Potencial da Membrana Mitocondrial , Proteolipídeos/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Baço/metabolismo , Baço/microbiologia
2.
mBio ; 12(3): e0150221, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34182776

RESUMO

Previously, we documented that Stenotrophomonas maltophilia encodes a type IV secretion system (T4SS) that allows the organism to kill, in contact-dependent fashion, heterologous bacteria, including wild-type Pseudomonas aeruginosa. Bioinformatic screens based largely on the presence of both a C-terminal consensus sequence and an adjacent gene encoding a cognate immunity protein identified 13 potential antibacterial effectors, most of which were highly conserved among sequenced strains of S. maltophilia. The immunity proteins of two of these proved especially capable of protecting P. aeruginosa and Escherichia coli against attack from the Stenotrophomonas T4SS. In turn, S. maltophilia mutants lacking the putative effectors RS14245 and RS14255 were impaired for killing not only laboratory E. coli but clinical isolates of P. aeruginosa, including ones isolated from the lungs of cystic fibrosis patients. That complemented mutants behaved as wild type did confirmed that RS14245 and RS14255 are required for the bactericidal activity of the S. maltophilia T4SS. Moreover, a mutant lacking both of these proteins was as impaired as a mutant lacking the T4SS apparatus, indicating that RS14245 and RS14255 account for (nearly) all of the bactericidal effects seen. Utilizing an interbacterial protein translocation assay, we determined that RS14245 and RS14255 are bona fide substrates of the T4SS, a result confirmed by examination of mutants lacking both the T4SS and the individual effectors. Delivery of the cloned 14245 protein (alone) into the periplasm resulted in the killing of target bacteria, indicating that this effector, a putative lipase, is both necessary and sufficient for bactericidal activity. IMPORTANCE S. maltophilia is an increasingly important opportunistic pathogen. Inherently resistant to many antibiotics, S. maltophilia is often associated with lung infection, being, among other things, a complicating factor in cystic fibrosis patients. Moreover, it is a common form of coinfection in COVID-19 patients. In these various clinical settings and in natural habitats, S. maltophilia coexists with other pathogens, including P. aeruginosa. Previously, we documented that S. maltophilia possesses a T4SS that kills other bacteria, a notable observation given that most prior work on interbacterial competition has highlighted bactericidal effects of type VI secretion systems. By utilizing approaches ranging from bioinformatics to mutant analysis to protein translocation assays, we have now identified two substrates of the Stenotrophomonas T4SS that largely mediate the killing of pathogenic P. aeruginosa. These results represent a major advance in understanding S. maltophilia, the roles of T4SSs, concepts regarding clinically relevant, interbacterial competition, and activities of bactericidal effectors.


Assuntos
Antibiose/genética , Escherichia coli/metabolismo , Pseudomonas aeruginosa/metabolismo , Stenotrophomonas maltophilia/genética , Sistemas de Secreção Tipo IV/metabolismo , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/prevenção & controle , Humanos , Stenotrophomonas maltophilia/metabolismo , Sistemas de Secreção Tipo IV/genética
3.
Sci Rep ; 11(1): 12703, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34135459

RESUMO

Secondary bacterial infections are a potentially fatal complication of influenza infection. We aimed to define the impact of secondary bacterial infections on the clinical course and mortality in coronavirus disease 2019 (COVID-19) patients by comparison with influenza patients. COVID-19 (n = 642) and influenza (n = 742) patients, admitted to a large tertiary center in Israel and for whom blood or sputum culture had been taken were selected for this study. Bacterial culture results, clinical parameters, and death rates were compared. COVID-19 patients had higher rates of bacterial infections than influenza patients (12.6% vs. 8.7%). Notably, the time from admission to bacterial growth was longer in COVID-19 compared to influenza patients (4 (1-8) vs. 1 (1-3) days). Late infections (> 48 h after admission) with gram-positive bacteria were more common in COVID-19 patients (28% vs. 9.5%). Secondary infection was associated with a higher risk of death in both patient groups 2.7-fold (1.22-5.83) for COVID-19, and 3.09-fold (1.11-7.38) for Influenza). The association with death remained significant upon adjustment to age and clinical parameters in COVID-19 but not in influenza infection. Secondary bacterial infection is a notable complication associated with worse outcomes in COVID-19 than influenza patients. Careful surveillance and prompt antibiotic treatment may benefit selected patients.


Assuntos
COVID-19/epidemiologia , COVID-19/mortalidade , Coinfecção/epidemiologia , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/epidemiologia , Bactérias Gram-Positivas/isolamento & purificação , Infecções por Bactérias Gram-Positivas/epidemiologia , Vírus da Influenza A/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/mortalidade , Pandemias , SARS-CoV-2/isolamento & purificação , Adulto , Idoso , COVID-19/virologia , Coinfecção/microbiologia , Feminino , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Influenza Humana/virologia , Israel/epidemiologia , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Admissão do Paciente , Estudos Retrospectivos
5.
Fish Shellfish Immunol ; 115: 189-197, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34147613

RESUMO

The present study examines the effectiveness of DNA vaccine against Aeromonas hydrophila through oral route using chitosan-tripolyphosphate (Cs-TPP) nanoparticles encapsulation. The virulent gene of outer membrane protein (OMP) and hemolysin (hly) related to pathogenicity of A. hydrophila was used to construct a DNA vaccine using pVAX1, and the construct was named as pVAX-OMP and pVAX-hly DNA vaccines. The pVAX-OMP and pVAX-hly DNA vaccines were encapsulated by Cs-TPP nanoparticles and size measured by field emission scanning electron microscopy (FE-SEM). The encapsulation efficiency of Cs-TPP nanoparticles was found to be 79.6% for pVAX-OMP DNA and 82.3% for pVAX-hly DNA binding with Cs-TPP nanoparticles. The stability and invitro release profile of plasmid DNA was also determined after encapsulation using DNase and chitosanase. DNA vaccines distribution in tissues was investigated in fish fed with the pVAX-OMP, pVAX-hly and pVAX-OMP+pVAX-hly encapsulated in Cs-TPP nanoparticles and confirmed by PCR and multiplex PCR. The results suggest that Cs-TPP nanoparticles encapsulated DNA vaccine delivered into fish by feeding. After oral vaccination of Labeo rohita were challenged with A. hydrophila by intraperitoneal injection. Relatively, gene expression of c- and g-type lysozyme followed by pro- and anti-inflammatory cytokines (Interlukin-10 and Tumor Growth Factor ß) was up-regulated in heart and kidney for pVAX-OMP+pVAX-hly vaccinated group. Moreover, fish fed with pVAX-OMP+pVAX-hly encapsulated in Cs-TPP nanoparticles had a significantly higher survival rate (76.2%) against A. hydrophila. This study concludes that pVAX-OMP and pVAX-hly DNA vaccines can be delivered orally using Cs-TPP nanoparticles for protection against A. hydrophilainfection.


Assuntos
Vacinas Bacterianas/administração & dosagem , Quitosana/análogos & derivados , Cyprinidae , Doenças dos Peixes/prevenção & controle , Infecções por Bactérias Gram-Negativas/veterinária , Vacinação/veterinária , Vacinas de DNA/administração & dosagem , Administração Oral , Aeromonas hydrophila/fisiologia , Animais , Proteínas da Membrana Bacteriana Externa/imunologia , Quitosana/administração & dosagem , Quitosana/imunologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/prevenção & controle , Proteínas Hemolisinas/imunologia , Nanopartículas/administração & dosagem
6.
BMC Infect Dis ; 21(1): 444, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001022

RESUMO

BACKGROUND: To investigate the trends and correlation between antibacterial consumption and carbapenem resistance in Gram-negative bacteria from 2012 to 2019 in a tertiary-care teaching hospital in southern China. METHODS: This retrospective study included data from hospital-wide inpatients collected between January 2012 and December 2019. Data on antibacterial consumption were expressed as defined daily doses (DDDs)/1000 patient-days. Antibacterials were classified according to the Anatomical Therapeutic Chemical (ATC) classification system. The trends in antimicrobial usage and resistance were analyzed by linear regression, while Pearson correlation analysis was used for assessing correlations. RESULTS: An increasing trend in the annual consumption of tetracyclines, ß-lactam/ß-lactamase inhibitor (BL/BLI) combinations, and carbapenems was observed (P < 0.05). Carbapenem resistance in Acinetobacter baumannii (A. baumannii) significantly increased (P < 0.05) from 18% in 2012 to 60% in 2019. Moreover, significant positive correlations were found between resistance to carbapenems in A. baumannii (P < 0.05) and Escherichia coli (E. coli; P < 0.05) and consumption of carbapenems, while the resistance rate of A. baumannii to carbapenems was positively correlated with cephalosporin/ß-lactamase inhibitor (C/BLI) combinations (P < 0.01) and tetracyclines usage (P < 0.05). We also found that use of quinolones was positively correlated with the resistance rate of Burkholderia cepacia (B. cepacia) to carbapenems (P < 0.05), and increasing uses of carbapenems (P < 0.01) and penicillin/ß-Lactamase inhibitor (P/BLI) combinations (P < 0.01) were significantly correlated with reduced resistance of Enterobacter cloacae (E. cloacae) to carbapenems. CONCLUSION: These results revealed significant correlations between consumption of antibiotics and carbapenem resistance rates in Gram-negative bacteria. Implementing proper management strategies and reducing the unreasonable use of antibacterial drugs may be an effective measure to reduce the spread of carbapenem-resistant Gram-negative bacteria (CRGN), which should be confirmed by further studies.


Assuntos
Farmacorresistência Bacteriana , Bactérias Gram-Negativas/metabolismo , Infecções por Bactérias Gram-Negativas/diagnóstico , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/metabolismo , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Burkholderia cepacia/efeitos dos fármacos , Burkholderia cepacia/isolamento & purificação , Burkholderia cepacia/metabolismo , Carbapenêmicos/farmacologia , Carbapenêmicos/uso terapêutico , Cefalosporinas/metabolismo , China , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Modelos Lineares , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Centros de Atenção Terciária , Tetraciclinas/metabolismo , Inibidores de beta-Lactamases/metabolismo
7.
BMC Infect Dis ; 21(1): 484, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34039307

RESUMO

BACKGROUND: Chromobacterium violaceum (C. violaceum) is a Gram-negative saprophytic bacterium that is widespread in tropical and subtropical environments, and belongs to conditional pathogenic bacteria. Human infection with C. violaceum is rare, and this can be fatal when the diagnosis and treatment are delayed, especially recurrent infection patients. Since clinicians lack the knowledge for C. violaceum, rapid diagnosis and early appropriate antimicrobial treatment remains challenging. CASE PRESENTATION: A 15-year-old male student was hospitalized for dark abscess, pustules, severe pain in both legs, and fever for 11 days. There were pustules with gray-white pus and red infiltrating plaques on the back, and the subcutaneous nodules could be touched in front of both tibias, with scab, rupture and necrotic tissue of the lower limb. The patient's condition rapidly progressed. Therefore, next-generation sequencing (NGS), pustular secretion and blood culture were concurrently performed. The final diagnosis for this patient was C. violaceum infection by NGS. However, no bacterial or fungal growth was observed in the pustular secretion and blood culture. After 4 weeks of treatment, the patient was discharged from the hospital without any complications associated with C. violaceum infection. CONCLUSION: Rapid diagnosis and early appropriate antimicrobial treatment is the key to the successful treatment of C. violaceum infection, especially in patients with sepsis symptoms. This case highlights that NGS is a promising tool for the rapid diagnosis of C. violaceum infection, preventing the delayed diagnosis and misdiagnosis of C. violaceum infection in patients who tested negative for pustular secretion and blood culture.


Assuntos
Antibacterianos/uso terapêutico , Chromobacterium/isolamento & purificação , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Adolescente , Chromobacterium/efeitos dos fármacos , Chromobacterium/genética , Diagnóstico Precoce , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Humanos , Masculino , Reinfecção , Resultado do Tratamento
8.
Expert Rev Clin Pharmacol ; 14(7): 777-791, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33849355

RESUMO

Introduction: Increasing resistance of gram-negative bacteria poses a serious threat to global health. Thus, efficacious and safe antibiotics against resistant pathogens are urgently needed. Cefiderocol, a siderophore cephalosporin, addresses this unmet need.Areas covered: For this article, we screened all preclinical and clinical studies on cefiderocol published by January 2021 on PubMed. Also, regulatory documents, recent conference contributions, and selected data of antibiotic competitors are reviewed. We provide a comprehensive overview of the mode of action, in vitro and in vivo activity, pharmacokinetics/pharmacodynamics, and human pharmacokinetics. Last, we discuss the efficacy and safety data from the pivotal trials.Expert opinion: Cefiderocol was in vitro potent against virtually all gram-negative pathogens and resistance was rare. The target site pharmacokinetics (i.e. urinary and lung penetration) have been well described in humans and important PK/PD targets were reached. In the clinical trials, cefiderocol was non-inferior to carbapenems in the treatment of complicated urinary tract infections and nosocomial pneumonia. Against carbapenem-resistant gram-negative pathogens, cefiderocol was similar to the best available therapy, which was mainly based on the backbone agent colistin. Overall, a substantial body of evidence supports the clinical use of cefiderocol in patients with gram-negative infections and limited treatment options.


Assuntos
Antibacterianos/farmacologia , Cefalosporinas/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Animais , Antibacterianos/efeitos adversos , Antibacterianos/farmacocinética , Cefalosporinas/efeitos adversos , Cefalosporinas/farmacocinética , Farmacorresistência Bacteriana , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos
9.
J Med Microbiol ; 70(4)2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33826489

RESUMO

As the representative multidrug-resistant pathogen, Stenotrophomonas maltophilia has multiple intrinsic and acquired resistances, including carbapenem resistance. In companion animals, the antimicrobial susceptibility and sequence types (STs) of S. maltophilia are not well understood due to its limited isolation rate. We investigated the antimicrobial susceptibilities and multilocus sequence types (MLSTs) of 38 S. maltophilia strains isolated from dogs and cats in Japan. Prevalence of resistance was detected for imipenem (100 %), aztreonam (94.7 %), piperacillin (65.8 %), trimethoprim-sulfamethoxazole (65.8 %), and ceftazidime (60.5 %). Rates of resistances to chloramphenicol, minocycline, and levofloxacin were low (2.6-5.3 %). MLST analysis revealed that all 38 strains were assigned to 34 STs, including 11 previously reported STs and 23 newly identified STs. Phylogenetic analysis of MLSTs enabled categorization of 13 isolates (34.2 %) into genogroup 6, which is a major genogroup of human isolates. Multinational surveillance would be needed to clarify the significance of antimicrobial-resistant S. maltophilia isolates from companion animals.


Assuntos
Doenças do Gato/microbiologia , Doenças do Cão/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Bactérias Gram-Negativas/veterinária , Stenotrophomonas maltophilia/efeitos dos fármacos , Animais , Antibacterianos/uso terapêutico , Doenças do Gato/tratamento farmacológico , Gatos , Doenças do Cão/tratamento farmacológico , Cães , Genótipo , Infecções por Bactérias Gram-Negativas/microbiologia , Japão , Tipagem de Sequências Multilocus , Stenotrophomonas maltophilia/classificação
10.
Genes (Basel) ; 12(5)2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33919046

RESUMO

In patients with cystic fibrosis (CF), the lung is a remarkable ecological niche in which the microbiome is subjected to important selective pressures. An inexorable colonization by bacteria of both endogenous and environmental origin is observed in most patients, leading to a vicious cycle of infection-inflammation. In this context, long-term colonization together with competitive interactions among bacteria can lead to over-inflammation. While Pseudomonas aeruginosa and Staphylococcus aureus, the two pathogens most frequently identified in CF, have been largely studied for adaptation to the CF lung, in the last few years, there has been a growing interest in emerging pathogens of environmental origin, namely Achromobacter xylosoxidans and Stenotrophomonas maltophilia. The aim of this review is to gather all the current knowledge on the major pathophysiological traits, their supporting mechanisms, regulation and evolutionary modifications involved in colonization, virulence, and competitive interactions with other members of the lung microbiota for these emerging pathogens, with all these mechanisms being major drivers of persistence in the CF lung. Currently available research on A. xylosoxidans complex and S. maltophilia shows that these emerging pathogens share important pathophysiological features with well-known CF pathogens, making them important members of the complex bacterial community living in the CF lung.


Assuntos
Achromobacter denitrificans/genética , Fibrose Cística/microbiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Taxa de Mutação , Stenotrophomonas maltophilia/genética , Achromobacter denitrificans/patogenicidade , Adaptação Fisiológica , Fibrose Cística/complicações , Infecções por Bactérias Gram-Negativas/complicações , Humanos , Pulmão/microbiologia , Stenotrophomonas maltophilia/patogenicidade
12.
Am J Case Rep ; 22: e930888, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33861730

RESUMO

BACKGROUND Rahnella aquatilis is a facultatively anaerobic, gram-negative rod bacterium commonly found in freshwater. There are few cases of bacteremia caused by Rahnella aquatilis in the literature and even fewer cases reported of it causing sepsis in immunocompetent individuals. In this case report, we present a rare case of an immunocompetent individual who developed sepsis secondary to bacteremia caused by Rahnella aquatilis. CASE REPORT A 37-year-old immunocompetent man with cerebral palsy and chronic enterocutaneous fistulas, with an indwelling peripherally inserted central catheter (PICC) line for total parenteral nutrition (TPN), presented to the emergency department with complaints of increased enteric drainage from his fistula, rigors, and subjective fevers following a mechanical fall, which occurred approximately 1 week before. The day following admission, the patient developed septic shock and was transferred to the intensive care unit for vasopressor support. He was given intravenous cefepime and metronidazole for empiric therapy. Blood cultures grew Rahnella aquatilis, and antibiotic therapy was de-escalated to monotherapy with intravenous ceftriaxone. The patient's condition stabilized, his PICC line was replaced, and he was successfully discharged, and continued on outpatient antibiotic therapy with ceftriaxone. CONCLUSIONS This case report represents a novel presentation of septic shock secondary to bacteremia caused by a gram-negative rod bacterium, Rahnella aquatilis, in an immunocompetent host dependent on TPN via a PICC line. This case also demonstrates that Rahnella aquatilis can be susceptible to and treated successfully with intravenous ceftriaxone. Bacteremia caused by Rahnella aquatilis can cause a swift, aggressive decompensation and should be treated with antibiotics immediately.


Assuntos
Bacteriemia/diagnóstico , Paralisia Cerebral/complicações , Infecções por Bactérias Gram-Negativas/diagnóstico , Rahnella/isolamento & purificação , Choque Séptico/microbiologia , Adulto , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Imunocompetência , Masculino , Choque Séptico/diagnóstico
13.
J Med Microbiol ; 70(4)2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33830909

RESUMO

Introduction. In recent years, the Herbaspirillum genus has emerged as a pathogen in healthcare-related infections and has became stablished as an opportunistic pathogen.Hypothesis/Gap Statement. Little is known about the pathogenesis induced by Herbaspirillum genus.Aim. To evaluate the cytotoxic effects of genus Herbaspirillum, its ability to adhere to lung human cells and the ability of environmental and clinical strains of Herbaspirillum to induce pneumonia in mice.Methodology. Environmental and clinical isolates of Herbaspirillum were examined for their cytotoxic effects on the Calu-3 cell lineage. Cytotoxic activity of secretome was tested using MTT/neutral red assays and cell morphology analysis. Herbaspirillum adhesion on Calu-3 cells was assessed using bright-field microscopy and cell-associated bacteria were counted. A mouse model of acute lung infection was done using a clinical and an environmental strain. Adult male mice were used, and the pneumonia was inducted by intra-tracheal inoculation of 108 or 109 bacteria. Mice weight variations were evaluated at the end of the experiment. Bronchoalveolar lavage was collected and evaluated for total and differential cytology. A histological examination of lungs was performed giving a histological score.Results. The secretomes of all the strains induced morphological alterations in cells, but only H. seropedicae SmR1 were cytotoxic in MTT and neutral red assays. Clinical strains of H. frisingense AU14459 and H. hutttiense subsp. huttiense AU11883 exhibited low adherence to lung cells, while SmR1 was non-adhesive. Following intratracheal inoculation, mice treated with 109 c.f.u. of the SmR1 and AU11883 strains lost 18 and 6% of their weight over 7 days, respectively, and presented moderate clinical signs. Infected mice showed inflammatory cell infiltration in the perivascular and peribroncheal/peribronchiolar spaces. Bronchoalveolar fluid of mice inoculated with SmR1 109 c.f.u. presented an increase in total leucocyte cells and in neutrophils population.Conclusion. These in vivo and in vitro results provide insights into how some Herbaspirillum strains cause infection in humans, providing a basis for the characterization of pathogenesis studies on this emerging infectious agent.


Assuntos
Exossomos/metabolismo , Infecções por Bactérias Gram-Negativas/microbiologia , Herbaspirillum/patogenicidade , Pneumonia/microbiologia , Animais , Aderência Bacteriana , Líquido da Lavagem Broncoalveolar/citologia , Linhagem Celular , Sobrevivência Celular , Infecções por Bactérias Gram-Negativas/patologia , Herbaspirillum/isolamento & purificação , Herbaspirillum/metabolismo , Humanos , Pulmão/microbiologia , Pulmão/patologia , Masculino , Camundongos , Pneumonia/patologia , Virulência
14.
Fish Shellfish Immunol ; 113: 51-60, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33798718

RESUMO

Killer cell lectin-like receptor G subfamily 1 (KLRG1) is a receptor generally expressed on effector CD8+ T cells or NK cells at terminal differentiation stage, and it will be highly induced for lymphocyte cytotoxicity upon pathogen infection or lymphocyte activation. However, little is known about the character or function of KLRG1 in lower vertebrates. In present study, we reappraised a molecule that previously defined as KLRG1 in the genomic sequence of Nile tilapia Oreochromis niloticus, and identified it as an atypical KLRG1-like molecule (defined as On-KLRG1-L), and illustrated its potential function serving as a marker representing effector T lymphocytes of fish species. On-KLRG1-L consists of two C-type lectin-like domains (CTLDs) without transmembrane region, and the tertiary structure of the CTLD is highly alike to that in mouse KLRG1. As a CTLD-containing protein, the recombinant On-KLRG1-L could bind PGN and several microbes in vitro. On-KLRG1-L was widely expressed in immune-associated tissues, with the highest expression level in the gill. Once Nile tilapia is infected by Aeromonas hydrophila, mRNA level of On-KLRG1-L in spleen lymphocytes were significantly up-regulated on 5 days after infection. Meanwhile, On-KLRG1-L protein was also induced on 5 or 8 days after A. hydrophila infection. Furthermore, we found both mRNA and protein levels of On-KLRG1-L were dramatically enhanced within several hours after spleen lymphocytes were activated by T cell-specific mitogen PHA in vitro. More importantly, the ratio of On-KLRG1-L+ T cells was also augmented after PHA stimulation. The observations suggested that the KLRG1-like molecule from Nile tilapia participated in lymphocyte activation and anti-bacterial adaptive immune response, and could serve as an activation marker of T lymphocytes. Our study thus provided new evidences to understand lymphocyte-mediated adaptive immunity of teleost.


Assuntos
Imunidade Adaptativa/genética , Ciclídeos/imunologia , Doenças dos Peixes/imunologia , Lectinas Tipo C/imunologia , Ativação Linfocitária/imunologia , Receptores Imunológicos/imunologia , Aeromonas hydrophila/fisiologia , Sequência de Aminoácidos , Animais , Biomarcadores/metabolismo , Doenças dos Peixes/microbiologia , Proteínas de Peixes/genética , Proteínas de Peixes/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Lectinas Tipo C/genética , Estrutura Terciária de Proteína , Receptores Imunológicos/genética , Alinhamento de Sequência/veterinária
15.
Fish Shellfish Immunol ; 113: 162-175, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33857622

RESUMO

Streptococcosis and motile aeromonad septicemia (MAS) are well-known diseases in tilapia culture, which cause mass mortality with significant economic losses. The development of feed-based bivalent vaccines in controlling these diseases has been initiated, however, the mechanisms of immunities and cross-protection in fish remain unclear. This study was conducted to assess the immuno-protective as well as the cross-protective efficacy of a newly developed feed-based bivalent vaccine against Streptococcus and Aeromonas infections in red hybrid tilapia. A total of five groups of fish were vaccinated orally through two different techniques; bivalent vaccine (inactivated Streptococcus iniae and Aeromonas hydrophila) sprayed on feed pellets (BS group); bivalent vaccine (inactivated S. iniae and A. hydrophila) incorporated in feed (BI group); monovalent inactivated S. iniae and A. hydrophila vaccine separately incorporated into feed as monovalent S. iniae (MS group) and monovalent A. hydrophila (MA group); and control group (without vaccine). The feed-based vaccine was delivered orally at 5% of body weight for five consecutive days. The booster doses were given in the same manner on weeks 2 and 6. Serum and skin mucus samples were collected to assess the IgM responses using indirect ELISA. The first administration of the feed-based vaccine stimulated the IgM levels that lasted until week 3, while the second booster ensured that the IgM levels remained high for a period of 16 weeks in the BI, MS and MA groups. The BI group developed a strong and significantly (P < 0.05) higher systemic and mucosal IgM responses against both S. iniae and A. hydrophila and also cross-protective antigen S. agalactiae and A. veronii compared to the BS and control groups. Quantitative real-time PCR results also showed that the relative expressions of IL-8, INF-γ and IgM in the BI immunized fish spleen, head kidney and hindgut exhibited various significant (P < 0.05) rising trends following both the vaccination and the challenge phase. On weeks 10, all fish were challenged through the intraperitoneal route, where relative percent survivals (RPS) of 82.22 ± 3.85% when challenged with S. iniae, 77.78 ± 3.85% when challenged with A. hydrophila and 77.78 ± 3.85% when co-challenged with both S. iniae and A. hydrophila were observed in the BI group, which were significantly higher (P < 0.05) compared to the other groups. The BI group also showed significantly (P < 0.05) higher partial cross-protections following challenges with S. agalactiae (RPS at 60.00 ± 6.67%) and A. veronii (RPS at 57.78 ± 7.70%). This study demonstrated that immunization with feed-based BI vaccine elicited immune responses that were capable of protecting red hybrid tilapia against streptococcosis and MAS.


Assuntos
Vacinas Bacterianas/imunologia , Ciclídeos/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Vacinas Combinadas/imunologia , Animais , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções Estreptocócicas/imunologia , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/veterinária , Vacinas Estreptocócicas/imunologia , Vacinas de Produtos Inativados/imunologia
16.
J Wildl Dis ; 57(2): 327-337, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33822150

RESUMO

Footrot is a worldwide economically important, debilitating disease caused by Dichelobacter nodosus. In sheep (Ovis aries), it is characterized by lesions of varying severity, depending on the strain, whereas Alpine ibex (Capra ibex) seem to develop severe lesions, whatever the strain. Healthy carriers occur in livestock but are rare in wild ruminants. Using a triangulation approach (retrospective questionnaire survey, necropsy database screening, and pathogen prevalence estimation in selected ibex colonies with and without footrot), we aimed at evaluating the importance of footrot in the ibex population, identifying potential risk factors for disease occurrence in this species, and defining the epidemiological role of ibex. Our study revealed that footrot occurs throughout the entire ibex territory (34% of the Swiss ibex colonies affected) but only as a sporadic disease (mostly one case per disease event), although the situation differed among footrot-positive colonies because half of them had experienced outbreak recurrences. Risk factor analysis for the occurrence of footrot in ibex colonies suggested an absence of an effect of meteorologic conditions, region, contacts with sheep or cattle (known to be very common healthy carriers of D. nodosus) and existing local disease control program. We found a significant effect only of contacts with sheep having footrot. Pathogen prevalence was very low in all investigated colonies. In conclusion, our results support previous data suggesting that ibex are susceptible spillover hosts, likely infected mainly by sympatric sheep displaying clinical signs.


Assuntos
Dichelobacter nodosus , Pododermatite Necrótica dos Ovinos/microbiologia , Doenças das Cabras/epidemiologia , Infecções por Bactérias Gram-Negativas/veterinária , Animais , Animais Selvagens , Pododermatite Necrótica dos Ovinos/epidemiologia , Cabras , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Suíça/epidemiologia
17.
Nat Microbiol ; 6(4): 512-523, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33782558

RESUMO

Antimicrobial resistance in neonatal sepsis is rising, yet mechanisms of resistance that often spread between species via mobile genetic elements, ultimately limiting treatments in low- and middle-income countries (LMICs), are poorly characterized. The Burden of Antibiotic Resistance in Neonates from Developing Societies (BARNARDS) network was initiated to characterize the cause and burden of antimicrobial resistance in neonatal sepsis for seven LMICs in Africa and South Asia. A total of 36,285 neonates were enrolled in the BARNARDS study between November 2015 and December 2017, of whom 2,483 were diagnosed with culture-confirmed sepsis. Klebsiella pneumoniae (n = 258) was the main cause of neonatal sepsis, with Serratia marcescens (n = 151), Klebsiella michiganensis (n = 117), Escherichia coli (n = 75) and Enterobacter cloacae complex (n = 57) also detected. We present whole-genome sequencing, antimicrobial susceptibility and clinical data for 916 out of 1,038 neonatal sepsis isolates (97 isolates were not recovered from initial isolation at local sites). Enterobacterales (K. pneumoniae, E. coli and E. cloacae) harboured multiple cephalosporin and carbapenem resistance genes. All isolated pathogens were resistant to multiple antibiotic classes, including those used to treat neonatal sepsis. Intraspecies diversity of K. pneumoniae and E. coli indicated that multiple antibiotic-resistant lineages cause neonatal sepsis. Our results will underpin research towards better treatments for neonatal sepsis in LMICs.


Assuntos
Farmacorresistência Bacteriana Múltipla , Bactérias Gram-Negativas/patogenicidade , Infecções por Bactérias Gram-Negativas/microbiologia , Sepse Neonatal/microbiologia , África/epidemiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Ásia/epidemiologia , Proteínas de Bactérias/genética , Países em Desenvolvimento , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Variação Genética , Genoma Bacteriano/genética , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/mortalidade , Humanos , Recém-Nascido , Sepse Neonatal/tratamento farmacológico , Sepse Neonatal/mortalidade , Filogenia , Plasmídeos/genética , beta-Lactamases/genética
18.
Sultan Qaboos Univ Med J ; 21(1): e66-e71, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33777425

RESUMO

Objectives: Stenotrophomonas maltophilia, a Gram-negative non-fermentative bacillus, has emerged as an important nosocomial pathogen in recent years. It is intrinsically resistant to many antibiotics and has the ability to acquire antibiotic resistance by multiple mechanisms. Treating Stenotrophomonas infections, therefore, is a serious challenge for physicians. This study aimed to investigate the antibiotic susceptibility patterns and risk factors contributing to S. maltophilia infections. Methods: A retrospective cross-sectional study was conducted at Sohar Hospital in Sohar, Oman. The demographic, clinical and microbiological data of individuals from whom S. maltophilia was isolated between September 2016 and August 2019 were reviewed. Descriptive statistics were presented as frequencies and percentages. Results: A total of 41 S. maltophilia isolates from clinical specimens of 41 patients were studied. Infection occurred predominantly in males (73%) and the majority of patients (88%) were either ≤5 years old or >60 years old. All inpatients had at least one comorbidity while 50% had more than one. All inpatients were exposed to various medical interventions such as intensive care (44%), mechanical ventilation (41%), haemodialysis (25%), Foley's catheterisation (13%) and central venous lines (6%). Most patients (81%) were in hospital longer than two weeks. The susceptibility rates of S. maltophilia to minocycline (97%), trimethoprim-sulfamethoxazole (93%) and levofloxacin (92%) were high; the rate was lowest for ceftazidime (50%). Conclusion: S. maltophilia was found to be an important nosocomial opportunistic pathogen. Prolonged hospital stay and exposure to various medical interventions were key factors contributing to the development of infection. Minocycline and ceftazidime were found to be the most and least susceptible drugs, respectively.


Assuntos
Antibacterianos/farmacologia , Infecção Hospitalar , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções Oportunistas/microbiologia , Stenotrophomonas maltophilia/efeitos dos fármacos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos Transversais , Farmacorresistência Bacteriana , Feminino , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Omã/epidemiologia , Estudos Retrospectivos , Stenotrophomonas maltophilia/isolamento & purificação
19.
Microbiologyopen ; 10(1): e1169, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33650802

RESUMO

A novel TaqMan 5-plex real-time PCR using a combination of locked nucleic acid-modified (LNA)- and minor groove binding (MGB)-conjugated DNA probes was developed for identification and differentiation between the four main pathogenic Brachyspira species in swine. B. hyodysenteriae, B. pilosicoli, and B. suanatina are identified using three hydrolysis probes targeting cpn60, while B. hampsonii is recognized by another nox specific probe. The assay also includes an exogenous internal control simultaneously verifying the PCR competency of the DNA samples. Validation of the novel assay was performed using DNA samples from 18 Brachyspira reference strains and 477 clinical samples obtained from porcine rectal swabs by comparing them with different PCR-based methods targeting nox, 16S rDNA, and 23S rDNA. The specificity of the assay was 100% without cross-reactivity or detection of different pathogens. Depending on the Brachyspira species, the limit of detection was between 10 and 20 genome equivalents with a cut-off threshold cycle (Ct) value of 37. The developed highly sensitive and specific 5-plex real-time PCR assay is easy to implement in routine veterinary diagnostic laboratories and enables rapid differentiation between the main four pathogenic Brachyspira species recognized in pigs using a single-tube approach.


Assuntos
Brachyspira/classificação , Brachyspira/genética , Infecções por Bactérias Gram-Negativas/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/métodos , Doenças dos Suínos/diagnóstico , Animais , DNA Bacteriano/genética , Genoma Bacteriano/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Limite de Detecção , Sensibilidade e Especificidade , Suínos , Doenças dos Suínos/microbiologia
20.
Medicine (Baltimore) ; 100(10): e24981, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33725868

RESUMO

RATIONALE: Necrotizing fasciitis (NF) is a rapidly progressing bacterial soft tissue infection with a high mortality rate. It is characterized by significant soft tissue destruction with associated sepsis. The mainstay of treatment is coverage with appropriate broad-spectrum antibiotic therapy and emergent surgical debridement. PATIENT CONCERNS: A previously healthy 66-year-old female presented with a deep laceration to her right, posterior calf with subsequent contamination with lake water. After the wound was irrigated and closed, the patient developed NF. DIAGNOSIS: Laceration of the right lower extremity complicated by NF secondary to Aeromonas sobria. INTERVENTIONS: The patient underwent emergent surgical debridements with intravenous broad-spectrum antibiotics and negative pressure wound therapy. The lower extremity was reconstructed with split-thickness skin grafts. OUTCOMES: The patient's initial penetrating trauma was closed in the emergency room, and the patient was discharged home with antibiotics. She returned the next day with unstable vitals and was admitted to the intensive care unit. Her condition continued to deteriorate, and she underwent serial surgical debridements. Her condition improved and was discharged home after 13 days in the hospital. LESSONS LEARNED: Close monitoring for NF is important for tissue infections sustained in aquatic environments. Timely identification and surgical management of NF increases overall survival.


Assuntos
Aeromonas/isolamento & purificação , Antibacterianos/administração & dosagem , Desbridamento , Fasciite Necrosante/microbiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Ferimentos Penetrantes/complicações , Idoso , Fasciite Necrosante/diagnóstico , Fasciite Necrosante/terapia , Feminino , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/terapia , Humanos , Lagos/microbiologia , Perna (Membro) , Transplante de Pele , Resultado do Tratamento , Ferimentos Penetrantes/microbiologia , Ferimentos Penetrantes/cirurgia
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