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1.
Bioinformatics ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38954842

RESUMO

SUMMARY: The reliable and timely recognition of outbreaks is a key component of public health surveillance for foodborne diseases. Whole genome sequencing (WGS) offers high resolution typing of foodborne bacterial pathogens and facilitates the accurate detection of outbreaks. This detection relies on grouping WGS data into clusters at an appropriate genetic threshold, however, methods and tools for selecting and adjusting such thresholds according to the required resolution of surveillance and epidemiological context are lacking. Here we present DODGE (Dynamic Outbreak Detection for Genomic Epidemiology), an algorithm to dynamically select and compare these genetic thresholds. DODGE can analyse expanding datasets over time and clusters that are predicted to correspond to outbreaks (or 'investigation clusters') can be named with the established genomic nomenclature systems to facilitate integrated analysis across jurisdictions. DODGE was tested in two real-world genomic surveillance datasets of different duration, two months from Australia and nine years from the UK. In both cases only a minority of isolates were identified as investigation clusters. Two known outbreaks in the UK dataset were detected by DODGE and were recognised at an earlier timepoint than the outbreaks were reported. These findings demonstrated the potential of the DODGE approach to improve the effectiveness and timeliness of genomic surveillance for foodborne diseases and the effectiveness of the algorithm developed. AVAILABILITY: DODGE is freely available at https://github.com/LanLab/dodge and can easily be installed using Conda. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

2.
Emerg Infect Dis ; 30(1): 199-202, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38147535

RESUMO

In Queensland, Australia, 31 of 96 Shiga toxin‒producing Escherichia coli cases during 2020-2022 were reported by a specialty pathology laboratory servicing alternative health practitioners. Those new cases were more likely to be asymptomatic or paucisymptomatic, prompting a review of the standard public health response.


Assuntos
Infecções por Escherichia coli , Síndrome Hemolítico-Urêmica , Escherichia coli Shiga Toxigênica , Humanos , Escherichia coli Shiga Toxigênica/genética , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/epidemiologia , Queensland/epidemiologia , Diarreia/diagnóstico , Síndrome Hemolítico-Urêmica/diagnóstico , Austrália/epidemiologia
3.
Clin Infect Dis ; 76(3): e1277-e1284, 2023 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-36056896

RESUMO

BACKGROUND: Prospective whole-genome sequencing (WGS)-based surveillance may be the optimal approach to rapidly identify transmission of multi-drug resistant (MDR) bacteria in the healthcare setting. METHODS: We prospectively collected methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), carbapenem-resistant Acinetobacter baumannii (CRAB), extended-spectrum beta-lactamase (ESBL-E), and carbapenemase-producing Enterobacterales (CPE) isolated from blood cultures, sterile sites, or screening specimens across three large tertiary referral hospitals (2 adult, 1 paediatric) in Brisbane, Australia. WGS was used to determine in silico multi-locus sequence typing (MLST) and resistance gene profiling via a bespoke genomic analysis pipeline. Putative transmission events were identified by comparison of core genome single nucleotide polymorphisms (SNPs). Relevant clinical meta-data were combined with genomic analyses via customised automation, collated into hospital-specific reports regularly distributed to infection control teams. RESULTS: Over 4 years (April 2017 to July 2021) 2660 isolates were sequenced. This included MDR gram-negative bacilli (n = 293 CPE, n = 1309 ESBL), MRSA (n = 620), and VRE (n = 433). A total of 379 clinical reports were issued. Core genome SNP data identified that 33% of isolates formed 76 distinct clusters. Of the 76 clusters, 43 were contained to the 3 target hospitals, suggesting ongoing transmission within the clinical environment. The remaining 33 clusters represented possible inter-hospital transmission events or strains circulating in the community. In 1 hospital, proven negligible transmission of non-multi-resistant MRSA enabled changes to infection control policy. CONCLUSIONS: Implementation of routine WGS for MDR pathogens in clinical laboratories is feasible and can enable targeted infection prevention and control interventions.


Assuntos
Infecção Hospitalar , Staphylococcus aureus Resistente à Meticilina , Adulto , Humanos , Criança , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Tipagem de Sequências Multilocus , Infecção Hospitalar/epidemiologia , Staphylococcus aureus Resistente à Meticilina/genética , Centros de Atenção Terciária
4.
Emerg Infect Dis ; 29(11): 2218-2228, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37877500

RESUMO

Melioidosis, caused by the environmental gram-negative bacterium Burkholderia pseudomallei, usually develops in adults with predisposing conditions and in Australia more commonly occurs during the monsoonal wet season. We report an outbreak of 7 cases of melioidosis in immunocompetent children in Australia. All the children had participated in a single-day sporting event during the dry season in a tropical region of Australia, and all had limited cutaneous disease. All case-patients had an adverse reaction to oral trimethoprim/sulfamethoxazole treatment, necessitating its discontinuation. We describe the clinical features, environmental sampling, genomic epidemiologic investigation, and public health response to the outbreak. Management of this outbreak shows the potential benefits of making melioidosis a notifiable disease. The approach used could also be used as a framework for similar outbreaks in the future.


Assuntos
Burkholderia pseudomallei , Melioidose , Adulto , Humanos , Criança , Melioidose/diagnóstico , Melioidose/tratamento farmacológico , Melioidose/epidemiologia , Burkholderia pseudomallei/genética , Austrália/epidemiologia , Genômica , Surtos de Doenças
5.
Appl Environ Microbiol ; 89(10): e0047223, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37800954

RESUMO

Cholera is a major public health problem in developing and underdeveloped countries; however, it remains of concern to developed countries such as Australia as international travel-related or locally acquired cholera or diarrheal disease cases are still reported. Cholera is mainly caused by cholera toxin (CT) producing toxigenic O1 and O139 serogroup Vibrio cholerae strains. While most toxigenic V. cholerae cases in Australia are thought to be caused by international-acquired infections, Australia has its own indigenous toxigenic and non-toxigenic O1 and non-O1, non-O139 V. cholerae (NOVC) strains. In Australia, in the 1970s and again in 2012, it was reported that south-east Queensland riverways were a reservoir for toxigenic V. cholerae strains that were linked to local cases. Further surveillance on environmental reservoirs, such as riverways, has not been reported in the literature in the last 10 years. Here we present data from sites previously related to outbreaks and surveillance sampling to detect the presence of V. cholerae using PCR in conjunction with MALDI-TOF and whole-genome sequencing. In this study, we were able to detect NOVC at all 10 sites with all sites having toxigenic non-O1, non-O139 strains. Among 133 NOVC isolates, 22 were whole-genome sequenced and compared with previously sequenced Australian O1 and NOVC strains. None of the samples tested grew toxigenic or non-toxigenic O1 or O139, responsible for epidemic disease. Since NOVC can be pathogenic, continuous surveillance is required to assist in theclinical and envir rapid identification of sources of any outbreaks and to assist public health authorities in implementing control measures. IMPORTANCE Vibrio cholerae is a natural inhabitant of aquatic environments, both freshwater and seawater, in addition to its clinical significance as a causative agent of acute diarrhea and extraintestinal infections. Previously, both toxigenic and non-toxigenic, clinical, and environmental V. cholerae strains have been reported in Queensland, Australia. This study aimed to characterize recent surveillance of environmental NOVC strains isolated from Queensland River waterways to understand their virulence, antimicrobial resistance profile and to place genetic current V. cholerae strains from Australia in context with international strains. The findings from this study suggest the presence of unique toxigenic V. cholerae in Queensland river water systems that are of public health concern. Therefore, ongoing monitoring and genomic characterization of V. cholerae strains from the Queensland environment is important and would assist public health departments to track the source of cholera infection early and implement prevention strategies for future outbreaks. The genomics of environmental V. cholerae could assist us to understand the natural ecology and evolution of this bacterium in natural environments with respect to global warming and climate change.


Assuntos
Doença Relacionada a Viagens , Vibrio cholerae , Humanos , Austrália/epidemiologia , Cólera/epidemiologia , Cólera/microbiologia , Queensland/epidemiologia , Rios
6.
Epidemiol Infect ; 151: e67, 2023 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-37045547

RESUMO

We investigated the potential effects of COVID-19 public health restrictions on the prevalence and distribution of Neisseria gonorrhoeae (NG) genotypes in our Queensland isolate population in the first half of the year 2020. A total of 763 NG isolates were genotyped to examine gonococcal strain distribution and prevalence for the first 6 months of 2020, with 1 January 2020 to 31 March 2020 classified as 'pre' COVID-19 restrictions (n = 463) and 1 April 2020 to 30 June 2020 classified as 'post' COVID-19 restrictions (n = 300). Genotypes most prevalent 'pre' restrictions remained proportionally high 'post' restrictions, with some significantly increasing 'post' restrictions. However, genotype diversity was significantly reduced 'post' restrictions. Overall, it seems public health restrictions (9-10 weeks) were not sufficient to affect rates of infection or reduce the prevalence of well-established genotypes in our population, potentially due to reduced access to services or health-seeking behaviours.


Assuntos
COVID-19 , Gonorreia , Neisseria gonorrhoeae , Genótipo , Gonorreia/epidemiologia , Queensland/epidemiologia , Prevalência
7.
Epidemiol Infect ; 151: e92, 2023 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-37212056

RESUMO

Toxigenic diphtheria is rare in Australia with generally fewer than 10 cases reported annually; however, since 2020, there has been an increase in toxin gene-bearing isolates of Corynebacterium diphtheriae cases in North Queensland, with an approximately 300% escalation in cases in 2022. Genomic analysis on both toxin gene-bearing and non-toxin gene-bearing C. diphtheriae isolated from this region between 2017 and 2022 demonstrated that the surge in cases was largely due to one sequence type (ST), ST381, all of which carried the toxin gene. ST381 isolates collected between 2020 and 2022 were highly genetically related to each other, and less closely related to ST381 isolates collected prior to 2020. The most common ST in non-toxin gene-bearing isolates from North Queensland was ST39, an ST that has also been increasing in numbers since 2018. Phylogenetic analysis demonstrated that ST381 isolates were not closely related to any of the non-toxin gene-bearing isolates collected from this region, suggesting that the increase in toxigenic C. diphtheriae is likely due to the expansion of a toxin gene-bearing clone that has moved into the region rather than an already endemic non-toxigenic strain acquiring the toxin gene.


Assuntos
Corynebacterium diphtheriae , Difteria , Surtos de Doenças , Humanos , Austrália/epidemiologia , Corynebacterium diphtheriae/genética , Difteria/epidemiologia , Toxina Diftérica/genética , Genômica , Filogenia , Queensland , Epidemiologia Molecular , Saúde Pública
8.
Sex Health ; 20(4): 296-302, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36972581

RESUMO

BACKGROUND: Neisseria gonorrhoeae (NG) can lead to serious reproductive and sexual health outcomes, and the annual number of NG notifications in Australia increased steadily from 10329 in 2010 to 29549 by 2020. Australian populations most affected are urban men who have sex with men and First Nations peoples living in remote areas, and a resurgence in urban heterosexuals has been observed since 2012. METHODS: A case series analysis of Queensland NG isolates (2010-15) exploring temporal trends and antimicrobial resistance by demographic and geographic distribution and genotype was performed. Proportions describe age, sex, strain, genogroup (NG multi-antigen sequence typing), region, swab site, antimicrobial sensitivity and isolate rates per 100000 population. Dominant genogroups were identified. RESULTS: Among 3953 isolates, the median age was 25years (IQR 20-34years) and most (n =2871/3915, 73%) were men. Brisbane city (68.8) and Far North Queensland (54.1) excluding Cairns showed the highest rates. Forty-six genogroups were documented, seven (G2992, G6876, G1415, G4186, G5, G1407 and G6937) comprised half of all isolates. The predominant male genogroup was G2992 (16%), and G6876 (20%) for females; G5 was predominantly male from 2010 to 2011, but equal in both sexes from 2012 to 2015. CONCLUSION: Considerable temporal, geographical and demographical diversity was observed in Queensland NG isolates, which has public health implications. Certain genogroups are more transient than others, and evidence suggests bridging from male-dominant networks to heterosexual networks. Molecular surveillance can enhance tracking the epidemiology and movement of NG in Australia, highlighting the necessity of genotyping to expose potentially prevalent strains circulating in undetected or underrepresented networks by current screening methods.


Assuntos
Gonorreia , Minorias Sexuais e de Gênero , Feminino , Humanos , Masculino , Adulto Jovem , Adulto , Neisseria gonorrhoeae , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Gonorreia/tratamento farmacológico , Gonorreia/epidemiologia , Homossexualidade Masculina , Queensland/epidemiologia , Epidemiologia Molecular/métodos , Farmacorresistência Bacteriana/genética , Austrália , Genótipo
9.
Infect Immun ; 90(4): e0056521, 2022 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-35258316

RESUMO

Lav is an autotransporter protein found in pathogenic Haemophilus and Neisseria species. Lav in nontypeable Haemophilus influenzae (NTHi) is phase-variable: the gene reversibly switches ON-OFF via changes in length of a locus-located GCAA(n) simple DNA sequence repeat tract. The expression status of lav was examined in carriage and invasive collections of NTHi, where it was predominantly not expressed (OFF). Phenotypic study showed lav expression (ON) results in increased adherence to human lung cells and denser biofilm formation. A survey of Haemophilus species genome sequences showed lav is present in ∼60% of NTHi strains, but lav is not present in most typeable H. influenzae strains. Sequence analysis revealed a total of five distinct variants of the Lav passenger domain present in Haemophilus spp., with these five variants showing a distinct lineage distribution. Determining the role of Lav in NTHi will help understand the role of this protein during distinct pathologies.


Assuntos
Infecções por Haemophilus , Haemophilus influenzae , Biofilmes , Haemophilus influenzae/genética , Haemophilus influenzae/metabolismo , Humanos , Sistemas de Secreção Tipo V/genética , Sistemas de Secreção Tipo V/metabolismo
10.
Emerg Infect Dis ; 28(1): 238-241, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34932458

RESUMO

We report a multistate Salmonella enterica serovar Heidelberg outbreak in Australia during 2018-2019. Laboratory investigation of cases reported across 5 jurisdictions over a 7-month period could not identify a source of infection but detected indicators of severity and invasiveness. The hospitalization rate of 36% suggested a moderately severe clinical picture.


Assuntos
Intoxicação Alimentar por Salmonella , Salmonella enterica , Austrália/epidemiologia , Surtos de Doenças , Humanos , Intoxicação Alimentar por Salmonella/epidemiologia , Sorogrupo
11.
BMC Microbiol ; 22(1): 99, 2022 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-35413802

RESUMO

BACKGROUND: The purpose of this study was to investigate the use of routinely available rectal swabs as a surrogate sample type for testing the gut microbiome and monitoring antibiotic effects on key gut microorganisms, of patients hospitalised in an intensive care unit. A metagenomic whole genome sequencing approach was undertaken to determine the diversity of organisms as well as resistance genes and to compare findings between the two sampling techniques. RESULTS: No significant difference was observed in overall diversity between the faeces and rectal swabs and sampling technique was not demonstrated to predict microbial community variation. More human DNA was present in the swabs and some differences were observed only for a select few anaerobes and bacteria also associated with skin and/or the female genitourinary system, possibly reflecting sampling site or technique. Antibiotics and collections at different times of admission were both considered significant influences on microbial community composition alteration. Detection of antibiotic resistance genes between rectal swabs and faeces were overall not significantly different, although some variations were detected with a potential association with the number of human sequence reads in a sample. CONCLUSION: Testing the gut microbiome using standard rectal swab collection techniques currently used for multi-resistant organism screening has been demonstrated to have utility in gut microbiome monitoring in intensive care. The use of information from this article, in terms of methodology as well as near equivalence demonstrated between rectal swabs and faeces will be able to support and potentially facilitate the introduction into clinical practice.


Assuntos
Microbioma Gastrointestinal , Microbiota , Antibacterianos , Cuidados Críticos , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/genética , Humanos , Microbiota/genética , RNA Ribossômico 16S/genética
12.
Clin Infect Dis ; 73(11): e4531-e4538, 2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-32772111

RESUMO

BACKGROUND: Diphtheria is a potentially fatal respiratory disease caused by toxigenic Corynebacterium diphtheriae. Although resistance to erythromycin has been recognized, ß-lactam resistance in toxigenic diphtheria has not been described. Here, we report a case of fatal respiratory diphtheria caused by toxigenic C. diphtheriae resistant to penicillin and all other ß-lactam antibiotics, and describe a novel mechanism of inducible carbapenem resistance associated with the acquisition of a mobile resistance element. METHODS: Long-read whole-genome sequencing was performed using Pacific Biosciences Single Molecule Real-Time sequencing to determine the genome sequence of C. diphtheriae BQ11 and the mechanism of ß-lactam resistance. To investigate the phenotypic inducibility of meropenem resistance, short-read sequencing was performed using an Illumina NextSeq500 sequencer on the strain both with and without exposure to meropenem. RESULTS: BQ11 demonstrated high-level resistance to penicillin (benzylpenicillin minimum inhibitory concentration [MIC] ≥ 256 µg/ml), ß-lactam/ß-lactamase inhibitors and cephalosporins (amoxicillin/clavulanic acid MIC ≥ 256 µg/mL; ceftriaxone MIC ≥ 8 µg/L). Genomic analysis of BQ11 identified acquisition of a novel transposon carrying the penicillin-binding protein (PBP) Pbp2c, responsible for resistance to penicillin and cephalosporins. When strain BQ11 was exposed to meropenem, selective pressure drove amplification of the transposon in a tandem array and led to a corresponding change from a low-level to a high-level meropenem-resistant phenotype. CONCLUSIONS: We have identified a novel mechanism of inducible antibiotic resistance whereby isolates that appear to be carbapenem susceptible on initial testing can develop in vivo resistance to carbapenems with repeated exposure. This phenomenon could have significant implications for the treatment of C. diphtheriae infection, and may lead to clinical failure.


Assuntos
Corynebacterium diphtheriae , Difteria , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Corynebacterium diphtheriae/genética , Difteria/tratamento farmacológico , Humanos , Lactamas/uso terapêutico , Testes de Sensibilidade Microbiana , Penicilinas/uso terapêutico
13.
BMC Microbiol ; 21(1): 92, 2021 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-33773572

RESUMO

BACKGROUND: Acquisition of IncI1 plasmids by members of the Enterobacteriaceae sometimes leads to transfer of antimicrobial resistance and colicinogeny as well as change of phage type in Salmonella Typhimurium. Isolates of S. Typhimurium from a 2015 outbreak of food poisoning were found to contain an IncI1 plasmid implicated in change of phage type from PT135a to U307 not previously reported. The origin of the changes of phage type associated with this IncI1 plasmid was investigated. In addition, a comparison of its gene composition with that of IncI1 plasmids found in local isolates of S. Typhimurium typed as U307 from other times was undertaken. This comparison was extended to IncI1 plasmids in isolates of phage types PT6 and PT6 var. 1 which are thought to be associated with acquisition of IncI1 plasmids. RESULTS: Analysis of IncI1 plasmids from whole genome sequencing of isolates implicated a gene coding for a 1273 amino acid protein present only in U307 isolates as the likely source of change of phage type. The IncI1 plasmids from PT6 and PT6 var. 1 isolates all had the ibfA gene present in IncI1 plasmid R64. This gene inhibits growth of bacteriophage BF23 and was therefore the possible source of change of phage type. A fuller comparison of the genetic composition of IncI1 plasmids from U307 isolates and PT6 and PT6 var. 1 isolates along with two IncI1 plasmids from S. Typhimurium isolates not showing change of phage type was undertaken. Plasmids were classified as either 'Delta' or 'Col' IncI1 plasmids according to whether genes between repZ and the rfsF site showed high identity to genes in the same location in R64 or ColIb-P9 plasmids respectively. Comparison of the tra gene sets and the pil gene sets across the range of sequenced plasmids identified Delta and Col plasmids with almost identical sequences for both sets of genes. This indicated a genetic recombination event leading to a switch between Delta and Col gene sets at the rfsF site. Comparisons of other gene sets showing significant variation among the sequenced plasmids are reported. Searches of the NCBI GenBank database using DNA and protein sequences of interest from the sequenced plasmids identified global IncI1 plasmids with extensive regions showing 99 to 100% identity to some of the plasmids sequenced in this study indicating evidence for widespread distribution of these plasmids. CONCLUSION: Two genes possibly associated with change of phage type were identified in IncI1 plasmids. IncI1 plasmids were classified as either 'Delta' or 'Col' plasmids and other sequences of significant variation among these plasmids were identified. This study offers a new perspective on the understanding of the gene composition of IncI1 plasmids. The sequences of newly sequenced IncI1 plasmids could be compared against the regions of significant sequence variation identified in this study to understand better their overall gene composition and relatedness to other IncI1 plasmids in the databases.


Assuntos
Plasmídeos/genética , Salmonella typhimurium/genética , Salmonella typhimurium/virologia , Tipagem Molecular
14.
Eur J Clin Microbiol Infect Dis ; 40(2): 279-286, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32888117

RESUMO

Epidemiological surveillance of Shigella spp. in Australia is conducted to inform public health response. Multi-drug resistance has recently emerged as a contributing factor to sustained local transmission of Shigella spp. All data were collected as part of routine public health surveillance, and strains were whole-genome sequenced for further molecular characterisation. 108 patients with an endemic regional Shigella flexneri strain were identified between 2016 and 2019. The S. flexneri phylogroup 3 strain endemic to northern Australia acquired a multi-drug resistance conferring blaDHA plasmid, which has an IncFII plasmid backbone with virulence and resistance elements typically found in IncR plasmids. This is the first report of multi-drug resistance in Shigella sp. in Australia that is not associated with men who have sex with men. This strain caused an outbreak of multi-drug-resistant S. flexneri in northern Australia that disproportionality affects Aboriginal and Torres Strait Islander children. Community controlled public health action is recommended.


Assuntos
Surtos de Doenças , Farmacorresistência Bacteriana Múltipla/genética , Disenteria Bacilar , Doenças Endêmicas , Shigella flexneri , Adolescente , Austrália/epidemiologia , Disenteria Bacilar/epidemiologia , Disenteria Bacilar/microbiologia , Humanos , Plasmídeos , Shigella flexneri/genética , Shigella flexneri/isolamento & purificação
15.
Clin Infect Dis ; 70(8): 1761-1763, 2020 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-31420664

RESUMO

We report the recent emergence of invasive meningococcal disease due to serogroup E in Queensland, Australia, in previously healthy patients. Molecular typing revealed the genotype of these strains to be E:P1.21-7,16:F5-36:ST-1157 (cc1157); when analyzed phylogenetically, compared with international cc1157 strains, they were relatively unrelated to each other.


Assuntos
Infecções Meningocócicas , Neisseria meningitidis , Austrália/epidemiologia , Genômica , Genótipo , Humanos , Infecções Meningocócicas/epidemiologia , Neisseria meningitidis/genética , Sorogrupo
16.
J Clin Microbiol ; 58(5)2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32102855

RESUMO

Klebsiella species are problematic pathogens in neonatal units and may cause outbreaks, for which the sources of transmission may be challenging to elucidate. We describe the use of whole-genome sequencing (WGS) to investigate environmental sources of transmission during an outbreak of extended-spectrum-ß-lactamase (ESBL)-producing Klebsiella michiganensis colonizing neonates. Ceftriaxone-resistant Klebsiella spp. isolated from neonates (or their mothers) and the hospital environment were included. Short-read sequencing (Illumina) and long-read sequencing (MinION; Oxford Nanopore Technologies) were used to confirm species taxonomy, to identify antimicrobial resistance genes, and to determine phylogenetic relationships using single-nucleotide polymorphism profiling. A total of 21 organisms (10 patient-derived isolates and 11 environmental isolates) were sequenced. Standard laboratory methods identified the outbreak strain as an ESBL-producing Klebsiella oxytoca, but taxonomic assignment from WGS data suggested closer identity to Klebsiella michiganensis Strains isolated from multiple detergent-dispensing bottles were either identical or closely related by single-nucleotide polymorphism comparison. Detergent bottles contaminated by K. michiganensis had been used for washing milk expression equipment. No new cases were identified once the detergent bottles were removed. Environmental reservoirs may be an important source in outbreaks of multidrug-resistant organisms. WGS, in conjunction with traditional epidemiological investigation, can be instrumental in revealing routes of transmission and guiding infection control responses.


Assuntos
Infecção Hospitalar , Infecções por Klebsiella , Infecção Hospitalar/epidemiologia , Detergentes , Surtos de Doenças , Genômica , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Klebsiella , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae , Filogenia , beta-Lactamases/genética
17.
Infect Immun ; 87(5)2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30833337

RESUMO

Nontypeable Haemophilus influenzae (NTHi) is a major human pathogen, responsible for several acute and chronic infections of the respiratory tract. The incidence of invasive infections caused by NTHi is increasing worldwide. NTHi is able to colonize the nasopharynx asymptomatically, and the exact change(s) responsible for transition from benign carriage to overt disease is not understood. We have previously reported that phase variation (the rapid and reversible ON-OFF switching of gene expression) of particular lipooligosaccharide (LOS) glycosyltransferases occurs during transition from colonizing the nasopharynx to invading the middle ear. Variation in the structure of the LOS is dependent on the ON/OFF expression status of each of the glycosyltransferases responsible for LOS biosynthesis. In this study, we surveyed a collection of invasive NTHi isolates for ON/OFF expression status of seven phase-variable LOS glycosyltransferases. We report that the expression state of the LOS biosynthetic genes oafA ON and lic2A OFF shows a correlation with invasive NTHi isolates. We hypothesize that these gene expression changes contribute to the invasive potential of NTHi. OafA expression, which is responsible for the addition of an O-acetyl group onto the LOS, has been shown to impart a phenotype of increased serum resistance and may serve as a marker for invasive NTHi.


Assuntos
Infecções por Haemophilus/genética , Infecções por Haemophilus/imunologia , Haemophilus influenzae/imunologia , Haemophilus influenzae/patogenicidade , Interações Hospedeiro-Patógeno/imunologia , Lipopolissacarídeos/biossíntese , Lipopolissacarídeos/genética , Lipopolissacarídeos/imunologia , Infecções por Haemophilus/patologia , Haemophilus influenzae/genética , Interações Hospedeiro-Patógeno/genética , Humanos , Queensland
18.
BMC Infect Dis ; 19(1): 660, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340776

RESUMO

BACKGROUND: Rapid diagnosis and appropriate treatment is imperative in bacterial sepsis due increasing risk of mortality with every hour without appropriate antibiotic therapy. Atypical infections with fastidious organisms may take more than 4 days to diagnose leading to calls for improved methods for rapidly diagnosing sepsis. Capnocytophaga canimorsus is a slow-growing, fastidious gram-negative bacillus which is a common commensal within the mouths of dogs, but rarely cause infections in humans. C. canimorsus sepsis risk factors include immunosuppression, alcoholism and elderly age. Here we report on the application of emerging nanopore sequencing methods to rapidly diagnose an atypical case of C. canimorsus septic shock. CASE PRESENTATION: A 62 year-old female patient was admitted to an intensive care unit with septic shock and multi-organ failure six days after a reported dog bite. Blood cultures were unable to detect a pathogen after 3 days despite observed intracellular bacilli on blood smears. Real-time nanopore sequencing was subsequently employed on whole blood to detect Capnocytophaga canimorsus in 19 h. The patient was not immunocompromised and did not have any other known risk factors. Whole-genome sequencing of clinical sample and of the offending dog's oral swabs showed near-identical C. canimorsus genomes. The patient responded to antibiotic treatment and was discharged from hospital 31 days after admission. CONCLUSIONS: Use of real-time nanopore sequencing reduced the time-to-diagnosis of Capnocytophaga canimorsus in this case from 6.25 days to 19 h. Capnocytophaga canimorsus should be considered in cases of suspected sepsis involving cat or dog contact, irrespective of the patient's known risk factors.


Assuntos
Mordeduras e Picadas/complicações , Capnocytophaga/isolamento & purificação , Choque Séptico/diagnóstico , Animais , Antibacterianos/uso terapêutico , Capnocytophaga/efeitos dos fármacos , Capnocytophaga/genética , Gatos , Cães , Feminino , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Hospedeiro Imunocomprometido , Pessoa de Meia-Idade , Nanoporos , Análise de Sequência de DNA , Choque Séptico/imunologia , Choque Séptico/microbiologia
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