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1.
Microb Pathog ; 159: 105145, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34411653

RESUMO

Pasteurella multocida (P. multocida) is a Gram-negative bacterium which causes diseases in poultry, livestock, and humans, resulting in huge economic losses. P. multocida serovar A CQ6 (PmCQ6) is a naturally occurring attenuated strain with a thin capsule. Thus, we aimed to explore why this strain is less virulent and produces less capsule compared with P. multocida serovar A strain CQ2 (PmCQ2). Analysis of capsular polysaccharide synthesis genes in PmCQ6 revealed that, compared with PmCQ2, there was only a single point mutation in the initiation codon sequence of the hyaC gene. To test whether this point mutation caused capsular deficiency and reduced virulence, we rescued this hyaC mutation and observed a restoration of capsule production and higher virulence. Transcriptome analysis showed that the hyaC point mutation led to a downregulation of capsule synthesis and/or iron utilization related-genes. Taken together, the results indicate that the start codon mutation of hyaC is an important factor affecting the capsule synthesis and virulence of PmCQ6.


Assuntos
Infecções por Pasteurella , Pasteurella multocida , Humanos , Infecções por Pasteurella/veterinária , Pasteurella multocida/genética , Mutação Puntual , Sorogrupo , Virulência/genética
2.
Epidemiol Mikrobiol Imunol ; 70(2): 110-117, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34412487

RESUMO

AIM: To present the results of whole genome sequencing (WGS) analysis of Streptococcus pneumoniae serotype 19A and to compare them with the respective data from Europe. The vaccine serotype 19A is widely distributed in the Czech Republic. MATERIAL AND METHODS: WGS was used in this study as the most powerful available method for detailed characterization of S. pneumoniae. Nineteen Czech isolates of S. pneumoniae 19A were analysed and compared with 415 European isolates included in the PubMLST database. RESULTS: S. pneumoniae serotype 19A causes all types of pathogen - host interaction, from carriage to noninvasive and invasive pneumococcal disease (IPD). In 2010 - 2019, 3872 cases of IPD were reported within the surveillance programme in the Czech Republic, with 323 of these caused by serotype 19A. WGS data of the Czech serotype 19A isolates show a numerous and genetically related subpopulation of three sequencing types: ST-199, ST-416, and ST-3017. Within this subpopulation, the largest is the cluster of nine ST-199 isolates. High relatedness of ST-199 isolates is also confirmed by the fact that all but one isolate, 117/2019 (novel rST- -137805), share the same ribosome sequencing profile - rST-11365. Outside the above-mentioned subpopulation, there are only four isolates that form three separate genetic lines of serotype 19A. A highly similar situation is observed across European countries, where about half of all serotype 19A isolates form a genetically closely related subpopulation (ST-199, ST-416, ST-450, ST-667, ST-3017, and ST-10360) while isolates which are not part of this subpopulation represent a large number of unrelated genetic lines. CONCLUSIONS: The study has shown a mostly homogeneous population of S. pneumoniae serotype 19A to circulate in the post-vaccination era in both the Czech Republic and Europe, with some unrelated isolates located outside this population.


Assuntos
Streptococcus pneumoniae , República Tcheca/epidemiologia , Europa (Continente)/epidemiologia , Humanos , Sorogrupo , Sorotipagem , Streptococcus pneumoniae/genética , Vacinas Conjugadas , Sequenciamento Completo do Genoma
3.
Anal Chem ; 93(32): 11089-11098, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34339167

RESUMO

The need for efficient and accurate identification of pathogens in seafood and the environment has become increasingly urgent, given the current global pandemic. Traditional methods are not only time consuming but also lead to sample wastage. Here, we have proposed two new methods that involve Raman spectroscopy combined with a long short-term memory (LSTM) neural network and compared them with a method using a normal convolutional neural network (CNN). We used eight strains isolated from the marine organism Urechis unicinctus, including four kinds of pathogens. After the models were configured and trained, the LSTM methods that we proposed achieved average isolation-level accuracies exceeding 94%, not only meeting the requirement for identification but also indicating that the proposed methods were faster and more accurate than the normal CNN models. Finally, through a computational approach, we designed a loss function to explore the mechanism reflected by the Raman data, finding the Raman segments that most likely exhibited the characteristics of nucleic acids. These novel experimental results provide insights for developing additional deep learning methods to accurately analyze complex Raman data.


Assuntos
Aprendizado Profundo , Redes Neurais de Computação , Projetos de Pesquisa , Sorogrupo , Análise Espectral Raman
4.
BMC Infect Dis ; 21(1): 867, 2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34429064

RESUMO

BACKGROUND: Dengue fever is a mosquito born disease associated with self-limited to life threatening illness. First detected in Senegal in the nineteenth century, and despite its growing incidence this last decade, significant knowledge gaps exist in our knowledge of genetic diversity of circulating strains. This study highlights the circulating serotypes and genotypes between January 2017 and December 2018 and their spatial and temporal distribution throughout all regions of Senegal. METHODS: We used 56 dengue virus (DENV) strains for the analysis collected from 11 sampling areas: 39 from all regions of Senegal, and 17 isolates from Thiès, a particular area of the country. Two real time RT-qPCR systems were used to confirm dengue infection and corresponding serotypes. For molecular characterization, CprM gene was sequenced and submitted to phylogenetic analysis for serotypes and genotypes assignment. RESULTS: Three dengue virus serotypes (DENV-1-3) were detected by all used methods. DENV-3 was detected in 50% (28/56) of the isolates, followed by DENV-1 and DENV-2, each representing 25% (14/56) of the isolates. DENV-3 belongs to genotype III, DENV-1 to genotype V and DENV-2 to Cosmopolitan genotype. Serotype 3 was detected in 7 sampling locations and a co-circulation of different serotypes was observed in Thiès, Fatick and Richard-toll. CONCLUSIONS: These results emphasize the need of continuous DENV surveillance in Senegal to detect DENV cases, to define circulating serotypes/genotypes and to prevent the spread and the occurrence of severe cases.


Assuntos
Vírus da Dengue/genética , Dengue/epidemiologia , Dengue/diagnóstico , Vírus da Dengue/isolamento & purificação , Humanos , Filogenia , Vigilância em Saúde Pública , Senegal/epidemiologia , Sorogrupo , Análise Espacial
5.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(8): 973-977, 2021 Aug 06.
Artigo em Chinês | MEDLINE | ID: mdl-34445835

RESUMO

Objective: To analyze the carriage characteristics of Neisseria meningitidis (Nm) among healthy population of epidemic cerebrospinal meningitis in Shandong province. Methods: From April 2008 to April 2020, a total of 16 848 healthy population were recruited from Lixia District of Jinan City, Gaomi City of Weifang City, Jiaxiang County of Jining City, Wendeng District of Weihai City, Tancheng County of Linyi City and Linyi County of Dezhou City for the investigation.Throat swab samples were collected, Nm was isolated, cultured and identified, and Nm carrying characteristics of healthy population with different characteristics were analyzed. Results: Among the 16 848 healthy population, male accounted for 51.86% (8 737). A total of 136 Nm strains were isolated, and the carriage rate was 0.81%. Among the 136 Nm strains, serogroup B (60.29%) and ungroupable strains (23.53%) were dominant. Analysis of the Nm carriage rate, that were higher in the healthy population of Linyi (1.39%) and Jinan (1.14%), higher in 13-16 years old (1.60%) and 17-19 years old (1.10%) healthy population, and higher in male (1.02%). Conclusion: The Nm carriage rate of healthy population is relatively low in Shandong Province, and the proportion of serogroup B and ungroupable Nm is relatively high.


Assuntos
Meningite Meningocócica , Neisseria meningitidis , Adolescente , Portador Sadio/epidemiologia , Cidades , Nível de Saúde , Humanos , Masculino , Meningite Meningocócica/epidemiologia , Sorogrupo
6.
Nat Commun ; 12(1): 4786, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34373455

RESUMO

Salmonella enterica serovar 4,[5],12:i:- (Salmonella 4,[5],12:i:-) is a monophasic variant of Salmonella Typhimurium that has emerged as a global cause of multidrug resistant salmonellosis. We used Bayesian phylodynamics, genomic epidemiology, and phenotypic characterization to describe the emergence and evolution of Salmonella 4,[5],12:i:- in Australia. We show that the interruption of the genetic region surrounding the phase II flagellin, FljB, causing a monophasic phenotype, represents a stepwise evolutionary event through the accumulation of mobile resistance elements with minimal impairment to bacterial fitness. We identify three lineages with different population dynamics and discrete antimicrobial resistance profiles emerged, likely reflecting differential antimicrobial selection pressures. Two lineages are associated with travel to South-East Asia and the third lineage is endemic to Australia. Moreover antimicrobial-resistant Salmonella 4,[5],12:i- lineages efficiently infected and survived in host phagocytes and epithelial cells without eliciting significant cellular cytotoxicity, suggesting a suppression of host immune response that may facilitate the persistence of Salmonella 4,[5],12:i:-.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Evolução Molecular , Salmonella enterica/classificação , Salmonella enterica/genética , Sorogrupo , Antibacterianos/farmacologia , Austrália , Teorema de Bayes , Linhagem Celular , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Flagelina/genética , Humanos , Imunidade , Metais Pesados/farmacologia , Filogenia , Salmonella enterica/efeitos dos fármacos , Salmonella typhimurium , Células THP-1 , Sequenciamento Completo do Genoma
7.
Front Cell Infect Microbiol ; 11: 681937, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34447698

RESUMO

Dengue virus (DENV) infection is prevalent in tropical and subtropical regions of the world, which is fatal if untreated symptomatically. Emergence of new genotype within serotypes led to enhanced severity. The objective of the study is to identify the molecular characteristics of the DENV circulated during 2017 outbreak in Tamil Nadu, India, and to investigate the role of inflammatory cytokines in different "serotypes" and in "dengue severity". A total of 135 suspected samples were tested for DENV infection using IgM, IgG, and qPCR assay; where 76 samples were positive for DENV and analyzed for 12 inflammatory cytokines using ELISA. Serotyping shows 14 DENV-1, 22 DENV-2, 7 DENV-3, and 33 DENV-4, where DENV-4 was predominant. Among 76, 42 isolates were successfully sequenced for C-prM region and grouped. A lineage shift was observed in DENV-4 genotype. Irrespective of serotypes, IFNγ was significantly elevated in all serotypes than control as well as in primary infection than secondary, indicating its role in immune response. GM-CSF and IP-10 were significantly elevated in secondary infection and could be used as prognostic biomarkers for secondary infection. Our observation shows differential cytokine expression profile varied with each serotype, indicating serotype/genotype-specific viral proteins might play a major role in dengue severity. DENV-4 as dominant serotype was reported in Tamil Nadu for the first time during an outbreak with a mixed Th1/Th17 cytokine expression profile that correlated with disease severity. We conclude it is essential to identify circulating viral genotype and their fitness by mutational analysis to correlate with disease severity and immune status, as this correlation will be helpful in diagnostics and therapeutics applications.


Assuntos
Vírus da Dengue , Dengue , Citocinas , Dengue/epidemiologia , Vírus da Dengue/genética , Surtos de Doenças , Genótipo , Humanos , Índia/epidemiologia , Filogenia , Sorogrupo
8.
Lancet Glob Health ; 9(8): e1154-e1162, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34297962

RESUMO

BACKGROUND: Salmonella enterica serotype Typhi (S Typhi) is a major public health problem in low-income and middle-income countries. We aimed to investigate the effectiveness and impact of the typhoid conjugate vaccine Typbar-TCV against S Typhi among children in an outbreak setting of extensively drug-resistant (XDR) S Typhi in Pakistan. METHODS: This cohort study was done from Feb 21, 2018, to Dec 31, 2019. A census survey of all households located in the Qasimabad and Latifabad subdistricts of Hyderabad, Pakistan, was done at baseline, and 174 005 households were registered in the census. The Typbar-TCV immunisation campaign was initiated at temporary vaccination centres and 207 000 children aged 6 months to 10 years were vaccinated from Feb 21, 2018, to Dec 31, 2018. Social mobilisers informed parents about the vaccination process. Vaccination records were maintained electronically and linked with the household census surveys. Active surveillance for suspected and blood-culture-confirmed S Typhi was established in hospitals, clinics, and laboratories to assess the following outcomes: cases of suspected typhoid fever, culture-confirmed S Typhi, and antimicrobial resistance. An age-stratified cohort of 1100 vaccinated children was randomly selected from the vaccination registry, tested for Vi-IgG antibodies (data not reported), and followed up fortnightly (via telephone calls or household visits) until Dec 31, 2019, for ascertainment of outcomes during the study period. 20 847 vaccinated and unvaccinated children were randomly selected from the census registry as a quality control cohort and followed up from Oct 1 to Dec 31, 2019, for ascertainment of outcomes. Vaccine effectiveness against suspected, culture-confirmed, and XDR S Typhi was calculated. FINDINGS: 23 407 children from the census registry and surveillance system were included in the vaccine effectiveness analysis. 13 436 (57·4%) children were vaccinated, 12 214 (52·2%) were male, and 10 168 (43·4%) were aged 6-59 months. 5378 (23·0%) of 23 407 children had suspected S Typhi, among whom 775 (14·4%) had culture-confirmed S Typhi and 361 (68·6%) of 526 had XDR S Typhi. Vaccine effectiveness was 55% (95% CI 52-57) against suspected S Typhi (regardless of culture confirmation), 95% (93-96) against culture-confirmed S Typhi, and 97% (95-98) against XDR S Typhi. INTERPRETATION: Typbar-TCV is effective in protecting children against S Typhi infection in an outbreak setting, and was able, with moderate deployment, to curtail a major XDR S Typhi outbreak in a densely populated setting. The vaccine shows efficacy against S Typhi irrespective of antimicrobial resistance. FUNDING: Bill & Melinda Gates Foundation.


Assuntos
Surtos de Doenças/prevenção & controle , Farmacorresistência Bacteriana , Salmonella enterica/genética , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/imunologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Programas de Imunização , Lactente , Masculino , Paquistão/epidemiologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação , Sorogrupo , Febre Tifoide/epidemiologia , Febre Tifoide/microbiologia , Vacinas Conjugadas/imunologia
9.
Vaccine ; 39(35): 5015-5024, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34303562

RESUMO

Foot-and-mouth disease (FMD) is a global burden on the livestock industry. The causative agent, FMD virus (FMDV), is highly infectious and exists in seven distinct serotypes. Vaccination remains the most effective control strategy in endemic regions and current FMD vaccines are made from inactivated preparations of whole virus. The inherent instability of FMDV and the emergence of new strains presents challenges to efficacious vaccine development. Currently, vaccines available in East Africa are comprised of relatively historic strains with unreported stabilities. As an initial step to produce an improved multivalent FMD vaccine we have identified naturally stable East African FMDV strains for each of the A, O, SAT1 and SAT2 serotypes and investigated their potential for protecting ruminants against strains that have recently circulated in East Africa. Interestingly, high diversity in stability between and within serotypes was observed, and in comparison to non-African A serotype viruses reported to date, the East African strains tested in this study are less stable. Candidate vaccine strains were adapted to propagation in BHK-21 cells with minimal capsid changes and used to generate vaccinate sera that effectively neutralised a panel of FMDV strains selected to improve FMD vaccines used in East Africa. This work highlights the importance of combining tools to predict and assess FMDV vaccine stability, with cell culture adaptation and serological tests in the development of FMD vaccines.


Assuntos
Vírus da Febre Aftosa , Febre Aftosa , Vacinas Virais , Animais , Proteínas do Capsídeo/genética , Febre Aftosa/prevenção & controle , Sorogrupo
10.
J Vet Med Sci ; 83(9): 1378-1388, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34248104

RESUMO

Epizootic hemorrhagic disease (EHD) is an arthropod-borne disease of wild and domestic ruminants caused by the EHD virus (EHDV). To date, seven EHDV serotypes have been identified. In Japan, strain Ibaraki of EHDV serotype 2 has caused outbreaks of Ibaraki disease in cattle. In addition, EHDV serotype 7 (EHDV-7) has caused large-scale EHD epizootics. In mid-September 2016, eight cattle at a breeding farm in Fukuoka Prefecture, Japan developed fever. Since EHDV-7 was detected in sentinel cattle in western Japan in 2016, we suspected that the cause of this fever might be an EHDV-7 infection. In this study, we tested cattle for EHDV-7 and some other viruses. Consequently, EHDV was isolated from washed blood cells collected from three of the eight cattle, and genetic analysis of genome segment 2 revealed that this isolate was EHDV-7. Moreover, all affected cattle tested positive for anti-EHDV-7 neutralizing antibodies. Our results suggest that the fever was caused by EHDV-7 infection. In addition, we modified a conventional reverse transcription polymerase chain reaction assay for the specific detection of EHDV. This modified assay could detect various strains of EHDV isolated in Japan, Australia, and North America. Furthermore, the assay permitted the detection of EHDV-7 in blood cells collected from seven of the eight cattle. We believe that this modified assay will be a useful tool for the diagnosis of EHD.


Assuntos
Doenças dos Bovinos , Vírus da Doença Hemorrágica Epizoótica , Infecções por Reoviridae , Animais , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/epidemiologia , Vírus da Doença Hemorrágica Epizoótica/genética , Japão/epidemiologia , Infecções por Reoviridae/diagnóstico , Infecções por Reoviridae/epidemiologia , Infecções por Reoviridae/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Transcrição Reversa , Sorogrupo
11.
BMC Infect Dis ; 21(1): 632, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34210275

RESUMO

BACKGROUND: Infection with Salmonella enterica usually results in diarrhea, fever, and abdominal cramps, but some people become asymptomatic or chronic carrier as a source of infection for others. This study aimed to analyze the difference in serotype, antimicrobial resistance, and genetic profiles between Salmonella strains isolated from patients and those from asymptomatic people in Nantong city, China. METHODS: A total of 88 Salmonella strains were collected from patients and asymptomatic people from 2017 to 2018. Serotyping, antimicrobial susceptibility testing, and PFGE analysis were performed to analyze the characteristics of these strains. RESULTS: Twenty serotypes belonging to 8 serogroups were identified in the 88 Salmonella strains. S. Typhimurium remained to be the predominant serotype in strains from both patients and asymptomatic people. Among the 27 strains from patients, S. Enteritidis and S. Rissen were shown as the other two major serotypes, while S. London, S. Derby, and S. Meleagridis were demonstrated as the other significant serotypes among the 61 strains from asymptomatic people. Antimicrobial resistance testing revealed that 84.1% of strains from both resources were multi-drug resistant. PFGE displayed a highly discriminative ability to differentiate strains belonging to S. Derby, S. Typhimurium, etc., but could not efficiently differentiate serotypes like S. Enteritidis. CONCLUSIONS: This study's results demonstrated that S. Typhimurium could cause human infection in both symptomatic and asymptomatic state; S. London, S. Derby, and S. Meleagridis usually cause asymptomatic infection, while S. Enteritidis infection mainly results in human diseases. The high multi-drug resistance rate detected in the antimicrobial resistance and diverse PFGE profiles of these strains implied that the strains were isolated from different sources, and the increased surveillance of Salmonella from both patients and asymptomatic people should be taken to control the disease.


Assuntos
Salmonella/classificação , Salmonella/genética , Salmonella/isolamento & purificação , Sorogrupo , Adolescente , Adulto , Idoso , Infecções Assintomáticas/epidemiologia , Criança , Pré-Escolar , China/epidemiologia , Farmacorresistência Bacteriana Múltipla , Eletroforese em Gel de Campo Pulsado , Feminino , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Infecções por Salmonella/epidemiologia , Sorotipagem
12.
J Med Microbiol ; 70(7)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34309502

RESUMO

Introduction. Shiga toxin-producing Escherichia coli (STEC) can cause severe disease and large outbreaks. In England, the incidence and clinical significance of STEC serogroups other than O157 (non-O157) is unknown due to a testing bias for detection of STEC O157. Since 2013, the implementation of PCR to detect all STEC serogroups by an increasing number of diagnostic laboratories has led to an increase in the detection of non-O157 STEC.Hypothesis/Gap statement. Due to a bias in testing methodologies to select for STEC serogroup O157 in frontline diagnostic laboratories in most countries, very little surveillance data have been previously generated on non-O157 STEC.Aim. Five years (2014-2018) of STEC national surveillance data were extracted and descriptive analysis undertaken to assess disease severity of non-O157 STEC strains.Methods. Data from 1 January 2014 to 31 December 2018 were extracted from the National Enhanced Surveillance System for STEC and analysed.Results. The implementation of Gastrointestinal Polymerase Chain Reaction (GI-PCR) has resulted in a four-fold increase in the detection of non-O157 STEC cases between 2014 and 2018. There were 2579 cases infected with 97 different non-O157 serogroups. The gender distribution was similar amongst STEC O157 and non-O157 STEC cases with 57 and 56 % of cases being female respectively, but a significantly higher proportion of cases (P <0.001) under 5 years of age was observed among STEC O157 (22 %) cases compared to non-O157 STEC (14 %). The most common non-O157 serogroups were O26 (16 %), O146 (11 %), O91 (10 %), O128 (7 %), O103 (5 %) and O117 (3 %). Overall, rates of bloody diarrhoea were highest in O26 (44 %) and O103 (48 %) cases and lowest in STEC O117 cases (17 %). Strains harbouring Shiga toxin stx1a caused the highest proportion of diarrhoea (93 %) and caused the same level of bloody diarrhoea as stx2a (39 %). However, stx2a caused the highest proportion of vomiting (46 %), hospitalisation (49 %) and considerably more HUS (29 %) than other stx profiles.Conclusion. The implementation of PCR targeting stx at diagnostic laboratories has shown that non-O157 STEC, most notably STEC O26, are an emerging risk to public health.


Assuntos
Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli Shiga Toxigênica/isolamento & purificação , Adolescente , Adulto , Distribuição por Idade , Criança , Pré-Escolar , Inglaterra/epidemiologia , Feminino , Humanos , Masculino , Técnicas de Diagnóstico Molecular , Reação em Cadeia da Polimerase , Sorogrupo , Distribuição por Sexo , Toxina Shiga I/genética , Toxina Shiga II/genética , Escherichia coli Shiga Toxigênica/classificação , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/patogenicidade , Virulência/genética , Adulto Jovem
13.
J Med Microbiol ; 70(7)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34319224

RESUMO

Introduction. The emergence and spread of non-typhoidal Salmonella enterica (NTS) serovars resistant to fluoroquinolones and third- and higher-generation cephalosporins is a matter of great concern. Antimicrobial-resistant NTS is increasingly being discovered in humans, animals, food animals, food products, and agricultural environments. Pigs are considered a major reservoir of antimicrobial-resistant Salmonella spp.Hypothesis/Gap Statement. Fluoroquinolone-resistant Salmonella spp. warrant further surveillance and characterization for a better understanding of the bacteria isolated from animals.Aim. NTS isolated from pork from slaughterhouses across Thailand were characterized in terms of their serovars; resistance to fluoroquinolones, third-generation cephalosporins, and carbapenems; and antimicrobial resistance genes.Methodology. A total of 387 NTS isolates, collected from slaughtered pigs in ten provinces across Thailand between 2014 and 2015, were characterized based on their serovars, antimicrobial resistance genes, and susceptibility to fluoroquinolones, third-generation cephalosporins, and carbapenems.Results. Among all NTS isolates, S. enterica serovar Rissen was predominant. Antimicrobial resistance was exhibited in 93/387 isolates (24 %). Although 24 (6.2 %) isolates were susceptible to all the tested antimicrobials, they were found to possess ß-lactamase genes, such as bla TEM, bla SHV, or bla CTX-M. Mobilized colistin-resistant genes (mcr) and resistance to colistin were not observed in any tested isolate. Carbapenem resistance was detected in ten isolates (10.7 %); however, bla KPC, bla NDM, bla OXA-48-like, and bla IMP were not present. Among the 93 antimicrobial-resistant isolates, 87.1 % showed fluoroquinolone resistance with the quinolone resistance gene (qnrS) combined with topoisomerase genes parC (T57S) or gyrA (S83E/Y and D124E/G) substitutions, or topoisomerase gene substitutions alone.Conclusion. We found high fluoroquinolone resistance rates among the NTS isolates from pigs from slaughterhouses. The fluoroquinolone resistance mechanism in NTS was associated with the combination of qnrS and substitutions in gyrA, parC, or both. To prevent the transmission of antimicrobial-resistant NTS between animals and humans, continuous monitoring, surveillance, and regulation of Salmonella in the pork supply chain are pivotal.


Assuntos
Farmacorresistência Bacteriana/genética , Salmonelose Animal/microbiologia , Salmonella enterica , Suínos/microbiologia , Animais , Cefalosporinas/farmacologia , Fluoroquinolonas/farmacologia , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , Sorogrupo , Tailândia/epidemiologia
14.
Curr Microbiol ; 78(8): 3239-3245, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34223923

RESUMO

Streptococcus pneumoniae is the major cause of childhood pneumonia and related deaths in India. Widespread use of erythromycin for the treatment of pneumonia has led to the emergence of erythromycin resistance. Despite this increase in erythromycin resistance, there are very little data on resistance determinants from India. Hence, we aimed to perform the molecular characterization of erythromycin-resistant invasive pneumococcal isolates in India. In this study, 250 erythromycin-resistant invasive isolates obtained from four Indian hospitals between 2014 and 2019 were included. The isolates were reconfirmed by standard CDC protocols, followed by detection of erm(B), mef(A/E) genes, and screening for mutations in 23S rRNA, ribosomal proteins L4 and L22. Among the 250 erythromycin-resistant isolates, 46% (n = 114) and 35% (n = 87) carried the mef(A/E) gene and erm(B) gene, respectively; both genes were present in 8% (n = 20) of the isolates and 12% (n = 29) of the studied strains did not bear any of them. The major mutations associated with erythromycin resistance in 23S rRNA, such as A2060C, A2061G, and C2613G, were absent. The predominant serotypes were 19F, 14, 23F, 6A, 6B, 19A, and 9V. The major clonal complexes were CC320, followed by CC230 and CC63. The predominant gene was mef(A/E), and most of the serotypes were PCV13 (54%). This study contributes to the baseline understanding of the erythromycin resistance determinants associated with the serotypes and sequence types (ST) of Indian invasive S. pneumoniae.


Assuntos
Infecções Pneumocócicas , Streptococcus pneumoniae , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Eritromicina/farmacologia , Humanos , Índia , Testes de Sensibilidade Microbiana , Sorogrupo , Sorotipagem , Streptococcus pneumoniae/genética
15.
BMC Genomics ; 22(1): 507, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34225670

RESUMO

BACKGROUND: Salmonella is a major bacterial pathogen associated with a large number of outbreaks of foodborne diseases. Many highly virulent serovars that cause human illness belong to Salmonella serogroup C1, and Salmonella ser. Choleraesuis is a prominent cause of invasive infections in Asia. Comparative genomic analysis in our previous study showed that two homologous genes, SC0368 and SC0595 in Salmonella ser. Choleraesuis were unique to serogroup C1. In this study, two single-deletion mutants (Δ0368 and Δ0595) and one double-deletion mutant (Δ0368Δ0595) were constructed based on the genome. All these mutants and the wild-type strain were subjected to RNA-Seq analysis to reveal functional relationships of the two serogroup C1-specific genes. RESULTS: Data from RNA-Seq indicated that deletion of SC0368 resulted in defects in motility through repression of σ28 in flagellar regulation Class 3. Consistent with RNA-Seq data, results from transmission electron microcopy (TEM) showed that flagella were not present in △0368 and △0368△0595 mutants resulting in both swimming and swarming defects. Interestingly, the growth rates of two non-motile mutants △0368 and △0368△0595 were significantly greater than the wild-type, which may be associated with up-regulation of genes encoding cytochromes, enhancing bacterial proliferation. Moreover, the △0595 mutant was significantly more invasive in Caco-2 cells as shown by bacterial enumeration assays, and the expression of lipopolysaccharide (LPS) core synthesis-related genes (rfaB, rfaI, rfaQ, rfaY, rfaK, rfaZ) was down-regulated only in the △0368△0595 mutant. In addition, this study also speculated that these two genes might be contributing to serotype conversion for Salmonella C1 serogroup based on their apparent roles in biosynthesis of LPS and the flagella. CONCLUSION: A combination of biological and transcriptomic (RNA-Seq) analyses has shown that the SC0368 and SC0595 genes are involved in biosynthesis of flagella and complete LPS, as well as in bacterial growth and virulence. Such information will aid to revealing the role of these specific genes in bacterial physiology and evolution within the serogroup C1.


Assuntos
Flagelos , Salmonella , Ásia , Proteínas de Bactérias/genética , Células CACO-2 , Flagelos/genética , Humanos , Sorogrupo
16.
BMC Infect Dis ; 21(1): 661, 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34233627

RESUMO

BACKGROUND: Pneumococcal vaccine immunizations may be responsible for alterations in serotype epidemiology within a region. This study investigated the pneumococcal carriage prevalence and the impact of the 13-valent pneumococcal conjugate vaccine (PCV-13) on circulating serotypes among healthy children in Northern Ghana. METHODS: This was a cross sectional study conducted in the Kassena-Nankana districts of Northern Ghana from November to December during the dry season of 2018. Nasopharyngeal swabs collected from 193 participants were cultured per standard microbiological protocols and pneumococcal isolates were serotyped using the latex agglutination technique and the capsular Quellung reaction test. We examined for any association between the demographic characteristics of study participants and pneumococcal carriage using chi-square test and logistic regression. RESULTS: Of the 193 participants that were enrolled the mean age was 8.6 years and 54.4% were females. The carriage rate among the participants was 32.6% (63/193), and twenty different serotypes were identified. These included both vaccine serotypes (VT), 35% (7/20) and non-vaccine serotypes (NVT), 65% (13/20). The predominant serotypes (34 and 11A), both of which were NVT, accounted for a prevalence of 12.8%. PCV-13 covered only 35% of serotypes identified whiles 40% of serotypes are covered by PPV 23. CONCLUSION: Post-vaccination carriage of S. pneumoniae is high and is dominated by non-vaccine serotypes. There is therefore a need for the conduct of invasive pneumococcal disease surveillance (IPD) to find out if the high non-vaccine serotype carriage translates to disease. And in addition, a review of the currently used PCV-13 vaccine in the country would be considered relevant.


Assuntos
Portador Sadio/epidemiologia , Nasofaringe/microbiologia , Infecções Pneumocócicas/diagnóstico , Vacinas Pneumocócicas/administração & dosagem , Streptococcus pneumoniae/isolamento & purificação , Portador Sadio/microbiologia , Criança , Pré-Escolar , Estudos Transversais , Feminino , Gana/epidemiologia , Humanos , Lactente , Testes de Fixação do Látex , Masculino , Infecções Pneumocócicas/epidemiologia , Vacinas Pneumocócicas/imunologia , Prevalência , Sorogrupo , Streptococcus pneumoniae/imunologia , Vacinação
17.
Viruses ; 13(6)2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208667

RESUMO

Dengue fever, caused by the mosquito-borne dengue virus (DENV), has been endemic in Myanmar since 1970 and it has become a significant public health burden. It is crucial that circulating DENV strains are identified and monitored, and that their transmission efficiency and association with disease severity is understood. In this study, we analyzed DENV-1, DENV-2, DENV-3, and DENV-4 serotypes in 1235 serum samples collected in Myanmar between 2017 and 2019. Whole-genome sequencing of DENV-1-4 demonstrated that most DENV-1-4 strains had been circulating in Myanmar for several years. We also identified the emergence of DENV-3 genotype-I in 2017 samples, which persisted through 2018 and 2019. The emergence of the strain coincided with a period of increased DENV-3 cases and marked changes in the serotype dynamics. Nevertheless, we detected no significant differences between serum viral loads, disease severity, and infection status of individuals infected with different DENV serotypes during the 3-year study. Our results not only identify the spread of a new DENV-3 genotype into Yangon, Myanmar, but also support the importance of DENV evolution in changing the epidemic dynamics in endemic regions.


Assuntos
Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Vírus da Dengue/classificação , Vírus da Dengue/genética , Dengue/epidemiologia , Dengue/virologia , Genótipo , Adolescente , Substituição de Aminoácidos , Criança , Pré-Escolar , Dengue/diagnóstico , Dengue/história , Vírus da Dengue/isolamento & purificação , Surtos de Doenças , Variação Genética , Genoma Viral , História do Século XXI , Humanos , Mianmar , Filogenia , Estudos Soroepidemiológicos , Sorogrupo , Sequenciamento Completo do Genoma
18.
Microb Pathog ; 158: 105092, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34274454

RESUMO

The use of conjugate vaccines remains an effective intervention to prevent pneumococcal diseases. In order to expand vaccine coverage, the inclusion of pneumococcal proteins as carriers is a propitious alternative that has been explored over the past few years. In this study, pneumococcal surface protein A (PspA) clade 1, family 1 (PspA1) and clade 3, family 2 (PspA3) were used as carrier proteins for pneumococcal capsular polysaccharide serotype 6B (Ps6B). Employing an improved reductive amination chemistry, 50% of Ps6B was incorporated to each protein, PspA1 and PspA3. The effect of chemical modifications in Ps6B and PspA was assessed by an antigenicity assay and circular dichroism, respectively. Fragmentation and oxidation decreased the antigenicity of Ps6B while conjugation improved antigenicity. In the same manner, introduction of adipic acid dihydrazide (ADH) reduced PspA secondary structure content, which was partially restored after conjugation. Immunization of Ps6B-PspA1 and Ps6B-PspA3 conjugates in mice induced specific IgG antibodies against the Ps6B and the protein; and anti-PspA antibodies had functional activity against two pneumococcal strains with different serotypes. These results suggest that chemical coupling between Ps6B and PspA did not affect antigenic epitopes and support the further development of PspA as a carrier protein in pneumococcal conjugate vaccines to provide broader protection.


Assuntos
Anticorpos Antibacterianos , Infecções Pneumocócicas , Animais , Proteínas de Bactérias/genética , Camundongos , Camundongos Endogâmicos BALB C , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas , Polissacarídeos Bacterianos , Sorogrupo , Vacinas Conjugadas
19.
J Gen Virol ; 102(7)2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34280085

RESUMO

Pigs are susceptible to foot-and-mouth disease virus (FMDV), and the humoral immune response plays an essential role in protection against FMDV infection. However, little information is available about FMDV-specific mAbs derived from single B cells of pigs. This study aimed to determine the antigenic features of FMDV that are recognized by antibodies from pigs. Therefore, a panel of pig-derived mAbs against FMDV were developed using fluorescence-based single B cell antibody technology. Western blotting revealed that three of the antibodies (1C6, P2-7E and P2-8G) recognized conserved antigen epitopes on capsid protein VP2, and exhibited broad reactivity against both FMDV serotypes A and O. An alanine-substitution scanning assay and sequence conservation analysis elucidated that these porcine mAbs recognized two conserved epitopes on VP2: a linear epitope (2KKTEETTLL10) in the N terminus and a conformational epitope involving residues K63, H65, L66, F67, D68 and L81 on two ß-sheets (B-sheet and C-sheet) that depended on the integrity of VP2. Random parings of heavy and light chains of the IgGs confirmed that the heavy chain is predominantly involved in binding to antigen. The light chain of porcine IgG contributes to the binding affinity toward an antigen and may function as a support platform for antibody stability. In summary, this study is the first to reveal the conserved antigenic profile of FMDV recognized by porcine B cells and provides a novel method for analysing the antibody response against FMDV in its natural hosts (i.e. pigs) at the clonal level.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Proteínas do Capsídeo/imunologia , Vírus da Febre Aftosa/imunologia , Suínos/imunologia , Animais , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/isolamento & purificação , Afinidade de Anticorpos , Antígenos Virais/imunologia , Linfócitos B/imunologia , Proteínas do Capsídeo/química , Mapeamento de Epitopos , Epitopos/imunologia , Vírus da Febre Aftosa/classificação , Genes de Cadeia Pesada de Imunoglobulina , Genes de Cadeia Leve de Imunoglobulina , Imunoglobulina G/imunologia , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias Leves de Imunoglobulina/imunologia , Sorogrupo
20.
Vaccine ; 39(35): 5064-5073, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34301430

RESUMO

BACKGROUND: Streptococcus pneumoniae serotype 19A remains a significant cause of invasive pneumococcal disease (IPD) in Ireland despite the successful introduction of a 13-valent pneumococcal conjugate vaccine (PCV13) in 2010 which reduced the overall incidence of IPD in children. METHODS: Invasive Streptococcus pneumoniae serotype 19A isolates from the Irish reference laboratory between 2007-08 and 2017-18 were analysed using whole genome sequencing (WGS) to investigate the persistence of this vaccine-preventable serotype. We compared the entire national 19A collection to other international collections using a standardised nomenclature of Global Pneumococcal Sequencing Clusters (GPSC). RESULTS: Expansion of GPSCs and clonal complexes (CCs) may have been associated with vaccine introduction and antimicrobial prescribing policies. A sub-clade of GPSC1-CC320 (n = 25) unique to Ireland, included five of the ten vaccine failures/breakthrough cases identified (p = 0.0086). This sub-clade was not observed in a global GPSC1-CC320 collection. All isolates within the sub-clade (n = 25) contained a galE gene variant rarely observed in a global pneumococcal collection (n = 37/13454, p < 0.001) nor within GPSC1-CC320 (n = 19/227) (p < 0.001). The sub-clade was estimated to have emerged at the start of the PCV-vaccine era (ancestral origin 2000, range 1995-2004) and expanded in Ireland, with most isolated after PCV13 introduction (n = 24/25). CONCLUSIONS: The identification of a sub-clade/variant of serotype 19A highlights the benefit of using WGS to analyse genotypes associated with persistence of a preventable serotype of S. pneumoniae. Particularly as this sub-clade identified was more likely to be associated with IPD in vaccinated children than other 19A genotypes. It is possible that changes to the galE gene, which is involved in capsule production but outside of the capsular polysaccharide biosynthesis locus, may affect bacterial persistence within the population. Discrete changes associated with vaccine-serotype persistence should be further investigated and may inform vaccine strategies.


Assuntos
Infecções Pneumocócicas , Streptococcus pneumoniae , Criança , Genômica , Humanos , Lactente , Irlanda/epidemiologia , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas , Sorogrupo , Sorotipagem , Streptococcus pneumoniae/genética
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