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BACKGROUND: The widespread increase in multiple variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) since 2020 is causing significant health concerns worldwide. While whole-genome sequencing (WGS) has played a leading role in surveillance programs, many local laboratories lack the expertise and resources. Thus, we aimed to investigate the circulating SARS-CoV-2 variants and evaluate the performance of multiplexed real-time reverse transcription-PCR (RT-PCR) for screening and monitoring the emergence of new SARS-CoV-2 variants in Bangladesh. METHODS: A total of 600 confirmed SARS-CoV-2-positive cases were enrolled either prospectively or retrospectively from two divisions of Bangladesh. The samples were screened by variant RT-PCR targeting five mutations of the spike gene (N501Y, P681R, L452R, E484K, E484Q). A subsample of the study population was also selected for third-generation sequencing (TGS) and the results were compared to the variant RT-PCR screening. An in-depth comparison was made between the two methods in terms of congruence and cost-benefit. RESULT: Seven variants were detected among samples, with similar distributions of the variants across both divisions. Variant RT-PCR for the targeted mutations lead to a 98.5% call rate; only nine samples failed to be determined. No association was found regarding the demographic features, clinical criteria, or routine RT-PCR Ct values across the variants. The clade diversity of the sequenced subpopulation (n = 99) exhibited similar distributions across the two study sites and other epidemiologic variables. Variant RT-PCR successfully distinguished variants of concern (VOCs) and variants of interest (VOIs); however, 8% discrepancy was observed for the closest lineages. Moreover, the variant RT-PCR represented an ideal balance of cost, time, and accuracy that outweigh their limitations. CONCLUSION: Based on the strong agreement of variant RT-PCR with TGS, such rapid, easily accessible approaches of rapid strain typing are essential in the context of pandemic responses to guide both treatment decisions and public health measures.
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COVID-19 , SARS-CoV-2 , Bangladesh/epidemiología , Humanos , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , COVID-19/epidemiología , COVID-19/virología , COVID-19/diagnóstico , Femenino , Masculino , Mutación , Adulto , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Persona de Mediana Edad , Estudios Retrospectivos , Secuenciación Completa del Genoma/métodos , Prueba de Ácido Nucleico para COVID-19/métodos , Glicoproteína de la Espiga del Coronavirus/genética , Estudios ProspectivosRESUMEN
BACKGROUND: Antimicrobial resistance (AMR) is a major public health threat, affecting not only people but also animals and the environment. The One Health dimension of AMR is well known; however, data are lacking on the circulation of resistance-conferring genes, particularly in low-income countries. In 2017, WHO proposed a protocol called Tricycle, focusing on extended-spectrum ß-lactamase (ESBL)-Escherichia coli surveillance in the three sectors (humans, animals, and the environment). We implemented Tricycle in Madagascar to assess ESBL-E coli prevalence and describe intrasector and intersector circulation of ESBL-E coli and plasmids. METHODS: In this prospective study, we collected blood culture data from hospitalised patients with a suspected bloodstream infection processed from May 1, 2018, to April 30, 2019, and rectal swabs from healthy pregnant women from July 30, 2018, to April 27, 2019, both from three hospitals in Antananarivo, Madagascar; and caeca from farm chickens and surface waters from the Ikopa river, wastewater, and slaughterhouse effluents in the Antananarivo area, Madagascar, from April 9, 2018, to April 30, 2019. All samples were tested for ESBL-E coli. The genomes of all isolates were sequenced using a short-read method on NextSeq 500 and NovaSeq 6000 platforms (Illumina, San Diego, CA, USA) and those carrying plasmid replicons using an additional long-read method on a MinION platform (Oxford Nanopore Technologies, Oxford, UK). We characterised genomes of isolated strains (sequence type, resistance and virulence gene content, and plasmid replicons). We then compared isolates using the variant calling method (single-nucleotide polymorphism). FINDINGS: Data from 1056 blood cultures were collected and 289 pregnant women, 246 chickens, and 28 surface waters were sampled. Of the blood cultures, 18 contained E coli, of which seven (39%) were ESBL. ESBL-E coli was present in samples from 86 (30%) of 289 pregnant women, 140 (57%) of 246 chickens, and 28 (100%) of 28 surface water samples. The wet season (November to April) was associated with higher rates of carriage in humans (odds ratio 3·08 [1·81-5·27]) and chickens (2·79 [1·65-4·81]). Sequencing of 277 non-duplicated isolates (82 from pregnant women, 118 from chickens, and 77 from environmental samples) showed high genetic diversity (90 sequence types identified) with sector-specific genomic features. Single nucleotide polymorphism (SNP) analysis revealed that 169 (61%) of 277 isolates grouped into 44 clusters (two or more isolates) of closely related isolates (<40 SNPs), of which 24 clusters contained isolates from two sectors and five contained isolates from all three sectors. ESBL genes were all blaCTX-M variants (215 [78%] of 277 being blaCTX-M-15) and were located on a plasmid in 113 (41%) of 277 isolates. These ESBL-carrying plasmids were mainly IncF (63 [55%] of 114; one strain carried two plasmids) and IncY (42 [37%] of 114). The F31/36:A4:B1 (n=13) and F-:A-:B53 (n=8) pMLST subtypes, and the IncY plasmids, which were all highly conserved, were observed in isolates of differing genetic backgrounds from all sectors and were transferable in vitro by conjugation. INTERPRETATION: Despite sector-specific population structures, both ESBL-E coli strains and plasmids are circulating among humans, chickens, and the environment in Antananarivo, Madagascar. The Tricycle protocol can be implemented in a low-income country and represents a powerful tool for investigating dissemination of AMR from a One Health perspective. FUNDING: Fondation Mérieux and INSERM, Université Paris Cité.
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Pollos , Infecciones por Escherichia coli , Escherichia coli , beta-Lactamasas , Animales , Pollos/microbiología , Madagascar/epidemiología , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Humanos , beta-Lactamasas/genética , Estudios Prospectivos , Femenino , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/veterinaria , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/tratamiento farmacológico , Plásmidos/genética , Embarazo , Masculino , Adulto , Adulto Joven , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Persona de Mediana Edad , Adolescente , PrevalenciaRESUMEN
BACKGROUND: The 2022 African Cup of Nations (AFCON) took place in Cameroon from January 9th to February 5th, 2022, including Garoua in the north. We aimed to measure the impact of this event on the local COVID-19 epidemic given the implementation of a preventive strategy based on a health pass. METHODS: All players, staff and fans involved in the AFCON event were screened with PCR tests. Symptomatic cases were also continuously monitored in the general population and screened for variants of concern. Daily numbers of confirmed cases were compared to neighboring countries numbers retrieved from a public domain source. RESULTS: In total, 1479 and 2481 tests were performed in the general population and on asymptomatic AFCON attendees, respectively. From the latter, 12.5% were PCR-positive; 97% were infected with Omicron, with no significant difference compared to the passive program (G-test, P value = 0.162). Surveillance indicated the AFCON did not increase the number of symptomatic PCR-positive cases in the general population compared to neighboring countries. CONCLUSIONS: Though the COVID-19 epidemic was fueled by asymptomatic cases infected with the Omicron variant at the time, the non-therapeutic preventive measures implemented for AFCON mitigated an increase in the epidemic in the local population.
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COVID-19 , Reuniones Masivas , SARS-CoV-2 , Humanos , Camerún/epidemiología , COVID-19/epidemiología , COVID-19/prevención & control , Masculino , Femenino , AdultoRESUMEN
The widespread of chlorhexidine and antibiotics in the water bodies, which grew during the global COVID-19 pandemic, can increase the dispersion of antibiotic resistance. We assessed the occurrence of these pharmaceutical compounds as well as SARS-CoV-2 and analysed the bacterial community structure of hospital and urban wastewaters from Brazil, Cameroon, and Madagascar. Water and wastewater samples (n = 59) were collected between January-June 2022. Chlorhexidine, azithromycin, levofloxacin, ceftriaxone, gentamicin and meropenem were screened by Ultra-High-Performance Liquid Chromatography coupled with mass spectrometer. SARS-CoV-2 was detected based on the nucleocapsid gene (in Cameroon and Madagascar), and envelope and spike protein-encoding genes (in Brazil). The total community-DNA was extracted and used for bacterial community analysis based on the 16S rRNA gene. To unravel likely interaction between pharmaceutical compounds and/or SARS-CoV-2 with the water bacterial community, multivariate statistics were performed. Chlorhexidine was found in hospital wastewater effluent from Brazil with a maximum concentration value of 89.28 µg/L. Additionally, antibiotic residues such as azithromycin and levofloxacin were also present at concentrations between 0.32-7.37 µg/L and 0.11-118.91 µg/L, respectively. In Cameroon, azithromycin was the most found antibiotic present at concentrations from 1.14 to 1.21 µg/L. In Madagascar instead, ceftriaxone (0.68-11.53 µg/L) and levofloxacin (0.15-0.30 µg/L) were commonly found. The bacterial phyla statistically significant different (P < 0,05) among participating countries were Proteobacteria, Patescibacteria and Dependentiae which were mainly abundant in waters sampled in Africa and, other phyla such as Firmicutes, Campylobacterota and Fusobacteriota were more abundant in Brazil. The phylum Caldisericota was only found in raw hospital wastewater samples from Madagascar. The canonical correspondence analysis results suggest significant correlation of azithromycin, meropenem and levofloxacin with bacteria families such as Enterococcaceae, Flavobacteriaceae, Deinococcaceae, Thermacetogeniaceae and Desulfomonilaceae, Spirochaetaceae, Methanosaetaceae, Synergistaceae, respectively. Water samples were also positive for SARS-CoV-2 with the lowest number of hospitalized COVID-19 patients in Madagascar (n = 7) and Brazil (n = 30). Our work provides new data about the bacterial community profile and the presence of pharmaceutical compounds in the hospital effluents from Brazil, Cameroon, and Madagascar, whose limited information is available. These compounds can exacerbate the spreading of antibiotic resistance and therefore pose a risk to public health.
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Antibacterianos , COVID-19 , Clorhexidina , Aguas Residuales , COVID-19/epidemiología , Antibacterianos/análisis , Brasil , Camerún , Aguas Residuales/microbiología , Aguas Residuales/virología , Madagascar , Contaminantes Químicos del Agua/análisis , Bacterias , Monitoreo del Ambiente , SARS-CoV-2 , Microbiología del AguaRESUMEN
Despite the numerous articles published on the clinical characteristics and outcomes of COVID-19 with regard to high-income countries, little is known about patients in low- and middle-income countries (LMIC) in this context. The objective of this observational, prospective, hospital-based multicentric study was to describe clinical features and outcomes of laboratory-confirmed COVID-19 patients hospitalized in each of the participating centers in Bangladesh, Guinea, Ivory Coast, Lebanon, Madagascar, and Mali during the first year of the pandemic (March 5, 2020 to May 4, 2021). The study outcome was the clinical severity of COVID-19, defined as hospitalization in intensive care unit or death. Multivariate logistic regression models were performed to identify independent variables associated with disease severity. Overall, 1,096 patients were included. The median age was 49.0 years, ranging from 38.0 in Mali to 63.0 years in Guinea. The overall clinical severity of COVID-19 was 12.3%, ranging from 6.4% in Mali to 18.8% in Guinea. In both groups of patients <60 and ≥60 years old, cardiovascular diseases (adjusted odds ratio [aOR]: 1.99; 95% CI: 1.13-3.50, P = 0.02; aOR: 2.47; 95% CI: 1.33-4.57, P = 0.004) were independently associated with clinical severity, whereas in patients <60 years, diabetes (aOR: 2.13; 95% CI: 1.11-4.10, P = 0.02) was also associated with clinical severity. Our findings suggest that COVID-19-related severity and death in LMICs are mainly driven by older age. However, the presence of chronic diseases can also increase the risk of severity especially in younger patients.
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COVID-19 , Humanos , Persona de Mediana Edad , Países en Desarrollo , Estudios Prospectivos , SARS-CoV-2 , Factores de Riesgo , Hospitalización , Estudios RetrospectivosRESUMEN
Dugbe orthonairovirus (DUGV) is a tick-borne arbovirus within the order Bunyavirales. Although displaying mild pathogenic potential, DUGV is genetically related to the Crimean-Congo hemorrhagic fever virus (CCHFV), another orthonairovirus that causes severe liver dysfunction and hemorrhagic fever with a high mortality rate in humans. As we previously observed that CCHFV infection could massively recruit and lipidate MAP1LC3 (LC3), a core factor involved in the autophagic degradation of cytosolic components, we asked whether DUGV infection also substantially impacts the autophagy machinery in epithelial cells. We observed that DUGV infection does impose LC3 lipidation in cultured hepatocytes. DUGV infection also caused an upregulation of the MAP1LC3 and SQSTM1/p62 transcript levels, which were, however, more moderate than those seen during CCHFV infection. In contrast, unlike during CCHFV infection, the modulation of core autophagy factors could influence both LC3 lipidation and viral particle production: the silencing of ATG5 and/or ATG7 diminished the induction of LC3 lipidation and slightly upregulated the level of infectious DUGV particle production. Overall, the results are compatible with the notion that in epithelial cells infected with DUGV in vitro, the autophagy machinery may be recruited to exert a certain level of restriction on viral replication. Thus, the relationship between DUGV infection and autophagy in epithelial cells appears to present both similarities and distinctions with that seen during CCHFV infection.
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Virus de la Fiebre Hemorrágica de Crimea-Congo , Fiebre Hemorrágica de Crimea , Virus de la Enfermedad de los Ovinos de Nairobi , Humanos , Proteína Sequestosoma-1 , Virus de la Fiebre Hemorrágica de Crimea-Congo/fisiología , Autofagia , Proteínas , HepatocitosRESUMEN
We report the coding-complete genome sequences of 25 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sublineage B.1.1.529 Omicron strains obtained from Bangladeshi individuals in samples collected between December 2021 and January 2022. Genomic data were generated by Nanopore sequencing using the amplicon sequencing approach developed by the ARTIC Network.
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The role of microbial coinfection in the pathogenesis of pneumonia in children is not well known. The aim of this work was to describe the prevalence of microorganism co-detection in nasopharyngeal samples (NPS) of pneumonia cases and control subjects and to study the potential association between nasopharyngeal microorganism co-detection and pneumonia. A case-control study was carried out from 2010 to 2014 in nine study sites located in low- or middle-income countries. The data from 888 children under 5 years of age with pneumonia (cases) and 870 children under 5 without pneumonia (controls) were analyzed. Nasopharyngeal samples were collected; reverse transcription polymerase chain reaction (RT-PCR) enabled the detection of five bacteria and 19 viruses. Multiple, mixed-effects logistic regression modeling was undertaken to evaluate the association between microorganism co-detection and pneumonia. A single Streptococcus pneumoniae colonization was observed in 15.2% of the controls and 10.1% of the cases (P = 0.001), whereas S. pneumoniae and a single virus co-detection was observed in 33.3% of the cases and in 14.6% of the controls (P < 0.001). Co-detections with rhinovirus, respiratory syncytial virus, parainfluenza virus, human metapneumovirus, and influenza virus were more frequent in the cases compared with the controls (P < 0.001) and were significantly associated with pneumonia in multiple regression analysis. The proportion of single virus detection without bacterial co-detection was not different between cases and controls (13.6% versus 11.3%, P = 0.13). This study suggests that coinfection of S. pneumoniae and certain viruses may play a role in the pathophysiology of pneumonia in children.
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We respectfully thank Fabre et al. [...].
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Sistemas CRISPR-Cas , Salmonella typhi , Salmonella typhi/genéticaRESUMEN
Antimicrobial resistance is a major public health concern worldwide affecting humans, animals and the environment. However, data is lacking especially in developing countries. Thus, the World Health Organization developed a One-Health surveillance project called Tricycle focusing on the prevalence of ESBL-producing Escherichia coli in humans, animals, and the environment. Here we present the first results of the human community component of Tricycle in Madagascar. From July 2018 to April 2019, rectal swabs from 492 pregnant women from Antananarivo, Mahajanga, Ambatondrazaka, and Toamasina were tested for ESBL-E. coli carriage. Demographic, sociological and environmental risk factors were investigated, and E. coli isolates were characterized (antibiotic susceptibility, resistance and virulence genes, plasmids, and genomic diversity). ESBL-E. coli prevalence carriage in pregnant women was 34% varying from 12% (Toamasina) to 65% (Ambatondrazaka). The main risk factor associated with ESBL-E. coli carriage was the rainy season (OR = 2.9, 95% CI 1.3-5.6, p = 0.009). Whole genome sequencing was performed on 168 isolates from 144 participants. bla CTX-M-15 was the most frequent ESBL gene (86%). One isolate was resistant to carbapenems and carried the bla NDM-5 gene. Most isolates belonged to commensalism associated phylogenetic groups A, B1, and C (90%) and marginally to extra-intestinal virulence associated phylogenetic groups B2, D and F (10%). Multi locus sequence typing showed 67 different sequence types gathered in 17 clonal complexes (STc), the most frequent being STc10/phylogroup A (35%), followed distantly by the emerging STc155/phylogroup B1 (7%), STc38/phylogroup D (4%) and STc131/phylogroup B2 (3%). While a wide diversity of clones has been observed, SNP analysis revealed several genetically close isolates (n = 34/168) which suggests human-to-human transmissions. IncY plasmids were found with an unusual prevalence (23%), all carrying a bla CTX-M-15. Most of them (85%) showed substantial homology (≥85%) suggesting a dissemination of IncY ESBL plasmids in Madagascar. This large-scale study reveals a high prevalence of ESBL-E. coli among pregnant women in four cities in Madagascar associated with warmth and rainfall. It shows the great diversity of E. coli disseminating throughout the country but also transmission of specific clones and spread of plasmids. This highlights the urgent need of public-health interventions to control antibiotic resistance in the country.
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BACKGROUND: Serotyping of Streptococcus pneumoniae is important for monitoring of vaccine impact. Unfortunately, conventional and molecular serotyping is expensive and technically demanding. This study aimed to determine the ability of matrix-assisted laser desorption-ionisation time-of-flight (MALDI-TOF) mass spectrometry to discriminate between pneumococcal serotypes and genotypes (defined by global pneumococcal sequence cluster, GPSC). In this study, MALDI-TOF mass spectra were generated for a diverse panel of whole genome sequenced pneumococcal isolates using the bioMerieux VITEK MS in clinical diagnostic (IVD) mode. Discriminatory mass peaks were identified and hierarchical clustering was performed to visually assess discriminatory ability. Random forest and classification and regression tree (CART) algorithms were used to formally determine how well serotypes and genotypes were identified by MALDI-TOF mass spectrum. RESULTS: One hundred and ninety-nine pneumococci, comprising 16 serotypes and non-typeable isolates from 46 GPSC, were analysed. In the primary experiment, hierarchical clustering revealed poor congruence between MALDI-TOF mass spectrum and serotype. The correct serotype was identified from MALDI-TOF mass spectrum in just 14.6% (random forest) or 35.4% (CART) of 130 isolates. Restricting the dataset to the nine dominant GPSC (61 isolates / 13 serotypes), discriminatory ability improved slightly: the correct serotype was identified in 21.3% (random forest) and 41.0% (CART). Finally, analysis of 69 isolates of three dominant serotype-genotype pairs (6B-GPSC1, 19F-GPSC23, 23F-GPSC624) resulted in the correct serotype identification in 81.1% (random forest) and 94.2% (CART) of isolates. CONCLUSIONS: This work suggests that MALDI-TOF is not a useful technique for determination of pneumococcal serotype. MALDI-TOF mass spectra appear more associated with isolate genotype, which may still have utility for future pneumococcal surveillance activities.
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Serotipificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Streptococcus pneumoniae/clasificación , Análisis por Conglomerados , Genotipo , Humanos , Serogrupo , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/aislamiento & purificaciónRESUMEN
Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), is a global health concern and its treatment is problematic due to the rise in antimicrobial resistance (AMR). Rapid detection of patients infected with AMR positive S. Typhi is, therefore, crucial to prevent further spreading. Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated genes (CRISPR-Cas), is an adaptive immune system that initially was used for typing purposes. Later, it was discovered to play a role in defense against phages and plasmids, including ones that carry AMR genes, and, at present, it is being explored for its usage in diagnostics. Despite the availability of whole-genome sequences (WGS), very few studied the CRISPR-Cas system of S. Typhi, let alone in typing purposes or relation to AMR. In the present study, we analyzed the CRISPR-Cas system of S. Typhi using WGS data of 1059 isolates obtained from Bangladesh, India, Nepal, and Pakistan in combination with demographic data and AMR status. Our results reveal that the S. Typhi CRISPR loci can be classified into two groups: A (evidence level >2) and B (evidence level ≤2), in which we identified a total of 47 unique spacers and 15 unique direct repeats. Further analysis of the identified spacers and repeats demonstrated specific patterns that harbored significant associations with genotype, demographic characteristics, and AMR status, thus raising the possibility of their usage as biomarkers. Potential spacer targets were identified and, interestingly, the phage-targeting spacers belonged to the group-A and plasmid-targeting spacers to the group-B CRISPR loci. Further analyses of the spacer targets led to the identification of an S. Typhi protospacer adjacent motif (PAM) sequence, TTTCA/T. New cas-genes known as DinG, DEDDh, and WYL were also discovered in the S. Typhi genome. However, a specific variant of the WYL gene was only identified in the extensively drug-resistant (XDR) lineage from Pakistan and ciprofloxacin-resistant lineage from Bangladesh. From this work, we conclude that there are strong correlations between variations identified in the S. Typhi CRISPR-Cas system and endemic AMR positive S. Typhi isolates.
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Sistemas CRISPR-Cas/genética , Farmacorresistencia Bacteriana/genética , Salmonella typhi/genética , Fiebre Tifoidea/microbiología , Bangladesh , Variación Genética , Genoma Bacteriano , Humanos , India , Nepal , Pakistán , Salmonella typhi/aislamiento & purificaciónRESUMEN
BACKGROUND: Improving knowledge regarding Streptococcus pneumoniae distribution in pneumonia cases is important to better target preventive and curative measures. The objective was to describe S. pneumoniae serotypes in children with or without pneumonia. METHODS: It was a case-control study carried out in 8 developing and emerging countries between 2010 and 2014. Cases were children aged <5 years admitted to the hospital for pneumonia. Controls were children admitted for surgery or routine outpatient care. RESULTS: In nasopharyngeal samples, S. pneumoniae were detected in 68.2% of the cases and 47.5% of the controls (P < .001). Nasopharyngeal carriage was associated with a higher risk of being a case in 6/8 study sites (adjusted odds ratio ranged from 0.71 [95% confidence interval [CI], .39-1.29; P = .26] in India [Pune/Vadu] to 11.86 [95% CI, 5.77-24.41; P < .001] in Mongolia). The 13-valent pneumococcal conjugate vaccine (PCV13) serotypes were more frequently detected in cases with nasopharyngeal carriage (67.1%) than in controls with nasopharyngeal carriage (54.6%), P < .001. Streptococcus pneumoniae was detected in blood by polymerase chain reaction in 8.3% of the cases. Of 34 cases with an S. pneumoniae serotype detected in blood, 27 (79%) had the same serotype in the nasopharyngeal sample. CONCLUSIONS: The results confirm the assumption that the isolate carrying or causing disease in an individual is of the same serotype. Most serotypes independently associated with nasopharyngeal carriage or pneumonia are covered by PCV13, suggesting that increased PCV coverage would reduce the burden of S. pneumoniae-related pneumonia.
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Infecciones Neumocócicas , Neumonía , Anciano , Portador Sano/epidemiología , Estudios de Casos y Controles , Niño , Preescolar , Humanos , India , Lactante , Mongolia , Nasofaringe , Infecciones Neumocócicas/epidemiología , Vacunas Neumococicas , Serogrupo , Streptococcus pneumoniae , Vacunas ConjugadasRESUMEN
BACKGROUND: Typhoid fever, caused by Salmonella Typhi, follows a fecal-oral transmission route and is a major global public health concern, especially in developing countries like Bangladesh. Increasing emergence of antimicrobial resistance (AMR) is a serious issue; the list of treatments for typhoid fever is ever-decreasing. In addition to IncHI1-type plasmids, Salmonella genomic island (SGI) 11 has been reported to carry AMR genes. Although reports suggest a recent reduction in multidrug resistance (MDR) in the Indian subcontinent, the corresponding genomic changes in the background are unknown. RESULTS: Here, we assembled and annotated complete closed chromosomes and plasmids for 73 S. Typhi isolates using short-length Illumina reads. S. Typhi had an open pan-genome, and the core genome was smaller than previously reported. Considering AMR genes, we identified five variants of SGI11, including the previously reported reference sequence. Five plasmids were identified, including the new plasmids pK91 and pK43; pK43and pHCM2 were not related to AMR. The pHCM1, pPRJEB21992 and pK91 plasmids carried AMR genes and, along with the SGI11 variants, were responsible for resistance phenotypes. pK91 also contained qnr genes, conferred high ciprofloxacin resistance and was related to the H58-sublineage Bdq, which shows the same phenotype. The presence of plasmids (pHCM1 and pK91) and SGI11 were linked to two H58-lineages, Ia and Bd. Loss of plasmids and integration of resistance genes in genomic islands could contribute to the fitness advantage of lineage Ia isolates. CONCLUSIONS: Such events may explain why lineage Ia is globally widespread, while the Bd lineage is locally restricted. Further studies are required to understand how these S. Typhi AMR elements spread and generate new variants. Preventive measures such as vaccination programs should also be considered in endemic countries; such initiatives could potentially reduce the spread of AMR.
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Farmacorresistencia Bacteriana/genética , Genes Bacterianos/genética , Genómica , Salmonella typhi/genética , Bangladesh , Cromosomas Bacterianos/genética , Islas Genómicas/genética , Genotipo , Humanos , Anotación de Secuencia Molecular , Fenotipo , Plásmidos/genética , Salmonella typhi/efectos de los fármacos , Salmonella typhi/aislamiento & purificaciónRESUMEN
Typhoid fever, caused by Salmonella enterica serovar Typhi, is a global public health concern due to increasing antimicrobial resistance (AMR). Characterization of S Typhi genomes for AMR and the evolution of different lineages, especially in countries where typhoid fever is endemic such as Bangladesh, will help public health professionals to better design and implement appropriate preventive measures. We studied whole-genome sequences (WGS) of 536 S Typhi isolates collected in Bangladesh during 1999 to 2013 and compared those sequences with data from a recent outbreak in Pakistan reported previously by E. J. Klemm, S. Shakoor, A. J. Page, F. N. Qamar, et al. (mBio 9:e00105-18, 2018, https://doi.org/10.1128/mBio.00105-18), and a laboratory surveillance in Nepal reported previously by C. D. Britto, Z. A. Dyson, S. Duchene, M. J. Carter, et al. [PLoS Negl. Trop. Dis. 12(4):e0006408, 2018, https://doi.org/10.1371/journal.pntd.0006408]. WGS had high sensitivity and specificity for prediction of ampicillin, chloramphenicol, co-trimoxazole, and ceftriaxone AMR phenotypes but needs further improvement for prediction of ciprofloxacin resistance. We detected a new local lineage of genotype 4.3.1 (named lineage Bd) which recently diverged into a sublineage (named Bdq) containing qnr genes associated with high-level ciprofloxacin resistance. We found a ceftriaxone-resistant isolate with the blaCTX-M-15 gene and a genotype distinct from the genotypes of extensively drug-resistant (XDR) isolates from Pakistan. This result suggests a different source and geographical origin of AMR. Genotype 4.3.1 was dominant in all three countries but formed country-specific clusters in the maximum likelihood phylogenetic tree. Thus, multiple independent genetic events leading to ciprofloxacin and ceftriaxone resistance took place in these neighboring regions of Pakistan, Nepal, and Bangladesh. These independent mutational events may enhance the risk of global spread of these highly resistant clones. A short-term global intervention plan is urgently needed.IMPORTANCE Typhoid fever, caused by Salmonella enterica serovar Typhi, is responsible for an estimated burden of approximately 17 million new episodes per year worldwide. Adequate and timely antimicrobial treatment invariably cures typhoid fever. The increasing antimicrobial resistance (AMR) of S Typhi severely limits the treatment options. We studied whole-genome sequences (WGS) of 536 S Typhi isolates collected in Bangladesh between 1999 and 2013 and compared those sequences with data from a recent outbreak in Pakistan and a laboratory surveillance in Nepal. The analysis suggests that multiple ancestral origins of resistance against ciprofloxacin and ceftriaxone are present in three countries. Such independent genetic events and subsequent dissemination could enhance the risk of a rapid global spread of these highly resistant clones. Given the current treatment challenges, vaccination seems to be the most appropriate short-term intervention to reduce the disease burden of typhoid fever at a time of increasing AMR.