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1.
J Virol Methods ; 322: 114827, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37778540

ABSTRACT

The continued emergence and transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants requires ongoing genetic surveillance to support public health responses. The expansion of reliable next generation sequence (NGS) platforms has enabled the rapid characterisation of the constant emergence of new SARS-CoV-2 variants using nasopharyngeal swab specimens. Several studies have assessed the ability of COVIDSeq to type earlier SARS-CoV-2 strains (pre-Delta) rapidly and successfully, however, there is limited data showing suitability against Omicron variants. In the present study, we evaluated the performance of the Illumina COVIDSeq Assay as a streamlined amplicon-based NGS platform for detection and typing of Omicron variants. Our results demonstrate the high performance of SARS-CoV-2 sequencing using the COVIDSeq approach, with good repeatability, reproducibility and sensitivity for samples approaching CT 31. The COVIDSeq approach was 100% concordant with samples previously characterized by sequencing methods. The quick library preparation process and high throughput kit made it ideal for reflex testing, with a total time required for sequencing and analysis of approximately two days. This study demonstrates the effectiveness and versatility of the amplicon-based NGS characterisation method for SARS-CoV-2, providing a foundation for further research and development of custom-designed amplicon panels targeting different microorganisms.


Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , Reproducibility of Results , SARS-CoV-2/genetics , Biological Assay
2.
Front Microbiol ; 14: 1238542, 2023.
Article in English | MEDLINE | ID: mdl-37869655

ABSTRACT

RT-qPCR remains a key diagnostic methodology for COVID-19/SARS-CoV-2. Typically, nasal or saliva swabs from patients are placed in virus transport media (VTM), RNA is extracted at the pathology laboratory, and viral RNA is measured using RT-qPCR. In this study, we describe the use of TNA-Cifer Reagent E in a pre-clinical evaluation study to inactivate SARS-CoV-2 as well as prepare samples for RT-qPCR. Adding 1 part TNA-Cifer Reagent E to 5 parts medium containing SARS-CoV-2 for 10 min at room temperature inactivated the virus and permitted RT-qPCR detection. TNA-Cifer Reagent E was compared with established column-based RNA extraction and purification methodology using a panel of human clinical nasal swab samples (n = 61), with TNA-Cifer Reagent E showing high specificity (100%) and sensitivity (97.37%). Mixtures of SARS-CoV-2 virus and TNA-Cifer Reagent E could be stored for 3 days at room temperature or for 2 weeks at 4°C without the loss of RT-qPCR detection sensitivity. The detection sensitivity was preserved when TNA-Cifer Reagent E was used in conjunction with a range of VTM for saliva samples but only PBS (Gibco) and Amies Orange for nasal samples. Thus, TNA-Cifer Reagent E improves safety by rapidly inactivating the virus during sample processing, potentially providing a safe means for molecular SARS-CoV-2 testing outside traditional laboratory settings. The reagent also eliminates the need for column-based and/or automated viral RNA extraction/purification processes, thereby providing cost savings for equipment and reagents, as well as reducing processing and handling times.

3.
Sex Health ; 20(4): 296-302, 2023 08.
Article in English | MEDLINE | ID: mdl-36972581

ABSTRACT

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.


Subject(s)
Gonorrhea , Sexual and Gender Minorities , Female , Humans , Male , Young Adult , Adult , Neisseria gonorrhoeae , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Gonorrhea/drug therapy , Gonorrhea/epidemiology , Homosexuality, Male , Queensland/epidemiology , Molecular Epidemiology/methods , Drug Resistance, Bacterial/genetics , Australia , Genotype
4.
J Clin Microbiol ; 60(11): e0101222, 2022 Nov 16.
Article in English | MEDLINE | ID: mdl-36314799

ABSTRACT

The application of direct metagenomic sequencing from positive blood culture broth may solve the challenges of sequencing from low-bacterial-load blood samples in patients with sepsis. Forty prospectively collected blood culture broth samples growing Gram-negative bacteria were extracted using commercially available kits to achieve high-quality DNA. Species identification via metagenomic sequencing and susceptibility prediction via a machine-learning algorithm (AREScloud) were compared to conventional methods and other rapid diagnostic platforms (Accelerate Pheno and blood culture identification [BCID] panel). A two-kit method (using MolYsis Basic and Qiagen DNeasy UltraClean kits) resulted in optimal extractions. Taxonomic profiling by direct metagenomic sequencing matched conventional identification in 38/40 (95%) samples. In two polymicrobial samples, a second organism was missed by sequencing. Prediction models were able to accurately infer susceptibility profiles for 6 common pathogens against 17 antibiotics, with an overall categorical agreement (CA) of 95% (increasing to >95% for 5/6 of the most common pathogens, if Klebsiella oxytoca was excluded). The performance of whole-genome sequencing (WGS)-antimicrobial susceptibility testing (AST) was suboptimal for uncommon pathogens (e.g., Elizabethkingia) and some ß-lactamase inhibitor antibiotics (e.g., ticarcillin-clavulanate). The time to pathogen identification was the fastest with BCID (1 h from blood culture positivity). Accelerate Pheno provided a susceptibility result in approximately 8 h. Illumina-based direct sequencing methods provided results in time frames similar to those of conventional culture-based methods. Direct metagenomic sequencing from blood cultures for pathogen detection and susceptibility prediction is feasible. Additional work is required to optimize algorithms for uncommon species and complex resistance genotypes as well as to streamline methods to provide more rapid results.


Subject(s)
Blood Culture , Nucleic Acids , Blood Culture/methods , Microbial Sensitivity Tests , Anti-Bacterial Agents/pharmacology , Phenotype
5.
Diagnostics (Basel) ; 12(9)2022 Aug 24.
Article in English | MEDLINE | ID: mdl-36140458

ABSTRACT

The continuous transmission and evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has required that diagnostic capabilities be constantly monitored and updated as new variants emerge and prior variants disappear. Although whole genome sequencing provides full characterisation of SARS-CoV-2 directly from patient samples, this has limited throughput and requires sufficient resources. To enhance screening for circulating variants, we designed a rapid in-house RT-PCR assay to target a spike mutation (D950N) in Delta variants, which is not detected in the remaining variants of concern (VOCs). Assay sensitivity for detecting Delta variants was 93% and specificity was 100% using a sequenced sample bank of several lineages. As the D950N mutation is prevalent in >95% of the global Delta variant sequences deposited in GISAID, this assay has the potential to provide rapid results to determine if the samples are presumptively Delta variants and can support clinicians in timely clinical decision-making for effective treatments and surveillance.

6.
Diagn Microbiol Infect Dis ; 102(3): 115598, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34883385

ABSTRACT

The sensitivity of SARS-CoV-2 diagnostic tests is inherently linked to viral load. We explored whether average viral loads changed at a population level in Queensland, Australia during the early phase of the pandemic. RT-PCR threshold cycle (CT) values, a crude marker for viral load, were compared for samples collected in February/March-2020 to those collected in April/May-2020, noting that the major public health interventions began in late-March 2020. Positive detections peaked mid-March, which coincided with the highest detection numbers and lowest CT values. However, this changed from April where the later CT samples (CT > 30) predominated. Overall, in February/March 29% (267/922) of samples had CT values >30 cycles compared to 88% (559/636) in April/May. Our study shows that SARS-CoV-2 viral loads in patients may vary at a population level over time. This needs considering when assessing suitability of diagnostic methods, particularly when methods in question are known to have reduced sensitivity.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19 Testing , Humans , Pandemics , Viral Load
7.
Front Cell Infect Microbiol ; 11: 667680, 2021.
Article in English | MEDLINE | ID: mdl-34249774

ABSTRACT

Background: Sepsis contributes significantly to morbidity and mortality globally. In Australia, 20,000 develop sepsis every year, resulting in 5,000 deaths, and more than AUD$846 million in expenditure. Prompt, appropriate antibiotic therapy is effective in improving outcomes in sepsis. Conventional culture-based methods to identify appropriate therapy have limited yield and take days to complete. Recently, nanopore technology has enabled rapid sequencing with real-time analysis of pathogen DNA. We set out to demonstrate the feasibility and diagnostic accuracy of pathogen sequencing direct from clinical samples, and estimate the impact of this approach on time to effective therapy when integrated with personalised software-guided antimicrobial dosing in children and adults on ICU with sepsis. Methods: The DIRECT study is a pilot prospective, non-randomized multicentre trial of an integrated diagnostic and therapeutic algorithm combining rapid direct pathogen sequencing and software-guided, personalised antibiotic dosing in children and adults with sepsis on ICU. Participants and interventions: DIRECT will collect microbiological and pharmacokinetic samples from approximately 200 children and adults with sepsis admitted to one of four ICUs in Brisbane. In Phase 1, we will evaluate Oxford Nanopore Technologies MinION sequencing direct from blood in 50 blood culture-proven sepsis patients recruited from consecutive patients with suspected sepsis. In Phase 2, a further 50 consecutive patients with suspected sepsis will be recruited in whom MinION sequencing will be combined with Bayesian software-guided (ID-ODS) personalised antimicrobial dosing. Outcome measures: The primary outcome is time to effective antimicrobial therapy, defined as trough drug concentrations above the MIC of the pathogen. Secondary outcomes are diagnostic accuracy of MinION sequencing from whole blood, time to pathogen identification and susceptibility testing using sequencing direct from whole blood and from positive blood culture broth. Discussion: Rapid pathogen sequencing coupled with antimicrobial dosing software has great potential to overcome the limitations of conventional diagnostics which often result in prolonged inappropriate antimicrobial therapy. Reduced time to optimal antimicrobial therapy may reduce sepsis mortality and ICU length of stay. This pilot study will yield key feasibility data to inform further, urgently needed sepsis studies. Phase 2 of the trial protocol is registered with the ANZCTR (ACTRN12620001122943). Trial registration: Registered with the Australia New Zealand Clinical Trials Registry Number ACTRN12620001122943.


Subject(s)
Sepsis , Adult , Anti-Bacterial Agents/therapeutic use , Australia , Bayes Theorem , Child , Humans , Multicenter Studies as Topic , Pilot Projects , Prospective Studies , Sepsis/diagnosis , Sepsis/drug therapy , Treatment Outcome
11.
Sex Health ; 16(5): 500-507, 2019 09.
Article in English | MEDLINE | ID: mdl-31481151

ABSTRACT

Background Although rare, Neisseria gonorrhoeae treatment failures associated with ceftriaxone have been reported. The World Health Organization (WHO) recommends standardised protocols to verify these cases. Two cases from Australia were previously investigated using N. gonorrhoeae multiantigen sequence typing (NG-MAST), which has been used extensively to assess treatment failures. Case 1 pharyngeal isolates were indistinguishable, whereas Case 2 pharyngeal isolates were distinguished based on an 18-bp deletion in the major outer membrane porin encoded by the porB gene, questioning the reliability of NG-MAST results. Here we used whole-genome sequencing (WGS) to reinvestigate Cases 1 and 2, with a view to examining WGS to assess treatment failures. METHODS: Pre- and post-treatment isolates for each case underwent Illumina sequencing, and the two post-treatment isolates underwent additional long-read sequencing using Pacific Biosciences. Sequence data were interrogated to identify differences at single nucleotide resolution. RESULTS: WGS identified variation in the pilin subunit encoded by the pilE locus for both cases and the specific 18-bp porB deletion in Case 2 was confirmed, but otherwise the isolates in each case were indistinguishable. CONCLUSIONS: The WHO recommends standardised protocols for verifying N. gonorrhoeae treatment failures. Case 2 highlights the enhanced resolution of WGS over NG-MAST and emphasises the immediate effect that WGS can have in a direct clinical application for N. gonorrhoeae. Assessing the whole genome compared with two highly variable regions also provides a more confident predictor for determining treatment failure. Furthermore, WGS facilitates rapid comparisons of these cases in the future.


Subject(s)
Gonorrhea/drug therapy , Neisseria gonorrhoeae/genetics , Whole Genome Sequencing , Anti-Bacterial Agents/therapeutic use , Bacterial Outer Membrane Proteins/genetics , Drug Resistance, Bacterial/genetics , Humans , Neisseria gonorrhoeae/drug effects , Porins/genetics , Treatment Failure
12.
Methods Mol Biol ; 2042: 87-122, 2019.
Article in English | MEDLINE | ID: mdl-31385272

ABSTRACT

CtGEM typing was developed to subdivide the bacterial species Chlamydia trachomatis on the basis of genome phylogeny and anatomical tropism. The rationale was facilitation of surveillance for ocular strains, although the method is applicable to essentially any C. trachomatis surveillance application that does not require high resolution. CtGEM is a double-locus genotyping method. The loci included in the assay were identified by computerized analysis of 65 complete genomes for resolution optimized sets of single nucleotide polymorphisms (SNPs). From this, two PCR amplifiable fragments were defined. One, rg1, is within a hypothetical gene annotated as Jali-1891 within the C. trachomatis B_Jali20 genome. The other, ofr, is within the ompA gene which encodes the major outer membrane protein. Variation in rg1 is conferred by two SNPs defining four haplotypes that exhibit concordance with genome phylogeny. Variation within ofr is more complex and allows for inference of ompA genotype, either to the level of single genotype, or group of closely related genotypes. Two CtGEM formats were developed. One is based on interrogation of the two loci by high resolution melting analysis (HRMA), and the other based on analysis of the loci by Sanger sequencing. The genotypes defined identify known ocular genotypes, discriminate known ocular genotypes from each other, discriminate the major phylogenetic lineages of the species, and discriminate all ompA genotypes with the exception of closely related variants within the genotypes H, I, J cluster. The Sanger sequencing format provides slightly more resolution that the HRMA format with respect to ompA genotype. An unusual aspect of this method is that all possible combinations of rg1 haplotype, and inferred ompA genotype(s) have been given CtGEM typing numbers. This includes types that at this time have not been shown to exist.


Subject(s)
Chlamydia Infections/microbiology , Chlamydia trachomatis/genetics , DNA, Bacterial/genetics , Genotyping Techniques/methods , Chlamydia trachomatis/isolation & purification , DNA, Bacterial/analysis , Eye/microbiology , Humans , Phylogeny , Polymerase Chain Reaction/methods , Urogenital System/microbiology
13.
BMC Infect Dis ; 19(1): 571, 2019 Jul 02.
Article in English | MEDLINE | ID: mdl-31266450

ABSTRACT

BACKGROUND: Carbapenemase-producing organisms (CPOs) have emerged as antibiotic-resistant bacteria of global concern. Here we assessed the performance of the Carba (beta) assay, a multiplex real-time PCR assay developed by SpeeDx for the detection of key carbapenemase-encoding genes: KPC, NDM, OXA-48-like, IMP-4-like, and VIM. METHODS: DNA extracts of 180 isolates were tested with the Carba (beta) assay, using previously validated in-house TaqMan probe assays for the relevant carbapenemase genes as the reference standard. The Carba (beta) assay was then directly used to screen 460 DNA extracts of faecal specimens, with positive results subjected to the aforementioned in-house assays plus Sanger sequencing. RESULTS: The Carba (beta) assay correctly identified the presence of the respective carbapenemase genes in 154 of 156 isolates and provided negative results for all 24 non-CPO isolates. Two isolates provided positive results for OXA-48-like carbapenemase by the Carba (beta) assay only. The Carba (beta) assay had sensitivities of 100% for all targets, and specificities of 100% for KPC, NDM, IMP-4-like, and VIM targets, and 98.5% for OXA-48-like targets. When applied directly to faecal specimens, eight samples were positive by the Carba (beta) assay, two of which were confirmed by in-house TaqMan probe PCR or DNA sequencing. CONCLUSIONS: The Carba (beta) assay is highly sensitive and specific for detecting key carbapenemase genes in isolates. Further testing is required to assess this assay's suitability for direct screening of clinical specimens.


Subject(s)
Bacteria/genetics , Bacterial Proteins/genetics , Multiplex Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/methods , beta-Lactamases/genetics , Anti-Bacterial Agents , Bacteria/drug effects , Bacteriological Techniques/methods , Escherichia coli Proteins/genetics , Feces/microbiology , Humans , Sensitivity and Specificity
14.
J Antimicrob Chemother ; 74(8): 2214-2219, 2019 08 01.
Article in English | MEDLINE | ID: mdl-31170281

ABSTRACT

OBJECTIVES: Our aim was to investigate the emergence and spread of ciprofloxacin resistance in clinical Neisseria gonorrhoeae isolates in New South Wales, Australia, from the first reported case in 1991 until ciprofloxacin resistance was sustained at or above the WHO threshold for treatment change of 5% (1999), to inform future strategies for controlling gonococcal antimicrobial resistance. METHODS: The index isolate and all subsequent clinical isolates of ciprofloxacin-resistant N. gonorrhoeae in New South Wales from 1991 to 1999 were genotyped using a previously described method on the Agena MassARRAY iPLEX platform. Region of acquisition data, where available, were used to determine whether cases were travel associated. RESULTS: In New South Wales, of the 325 ciprofloxacin-resistant N. gonorrhoeae isolates reported from 1991 to 1999, 98% (320/325) were able to be recovered and 100% (320/320) were genotyped. There were 66 different genotypes, comprising 1-99 isolates each. Notably no single clone was found to account for ciprofloxacin resistance being sustained in the population, with considerable variability in genotype prevalence observed throughout the study period. A total of 65% (209/320) of genotyped isolates had information regarding the likely place of acquisition; of these, 44% (93/209) were associated with overseas travel or sexual contact with an overseas visitor. The first ciprofloxacin-resistant N. gonorrhoeae in New South Wales was associated with travel to Thailand. Index cases of each resistant genotype were significantly more likely to have been acquired overseas (51.5%), predominantly in Asia (45%, 30/66). CONCLUSIONS: The continued importation of multiple genotypes, rather than the expansion of a single genotype, led to ciprofloxacin-resistant N. gonorrhoeae being established in New South Wales.


Subject(s)
Anti-Bacterial Agents/pharmacology , Ciprofloxacin/pharmacology , Drug Resistance, Bacterial , Gonorrhea/epidemiology , Neisseria gonorrhoeae/drug effects , Neisseria gonorrhoeae/genetics , Cohort Studies , Female , Genotype , Gonorrhea/microbiology , Humans , Male , Microbial Sensitivity Tests , Neisseria gonorrhoeae/classification , New South Wales/epidemiology , Travel
15.
PLoS One ; 13(4): e0195454, 2018.
Article in English | MEDLINE | ID: mdl-29634761

ABSTRACT

Chlamydia trachomatis infects the urogenital tract (UGT) and eyes. Anatomical tropism is correlated with variation in the major outer membrane protein encoded by ompA. Strains possessing the ocular ompA variants A, B, Ba and C are typically found within the phylogenetically coherent "classical ocular lineage". However, variants B, Ba and C have also been found within three distinct strains in Australia, all associated with ocular disease in children and outside the classical ocular lineage. CtGEM genotyping is a method for detecting and discriminating ocular strains and also the major phylogenetic lineages. The rationale was facilitation of surveillance to inform responses to C. trachomatis detection in UGT specimens from young children. CtGEM typing is based on high resolution melting analysis (HRMA) of two PCR amplified fragments with high combinatorial resolving power, as defined by computerised comparison of 65 whole genomes. One fragment is from the hypothetical gene defined by Jali-1891 in the C. trachomatis B_Jali20 genome, while the other is from ompA. Twenty combinatorial CtGEM types have been shown to exist, and these encompass unique genotypes for all known ocular strains, and also delineate the TI and T2 major phylogenetic lineages, identify LGV strains and provide additional resolution beyond this. CtGEM typing and Sanger sequencing were compared with 42 C. trachomatis positive clinical specimens, and there were no disjunctions. CtGEM typing is a highly efficient method designed and tested using large scale comparative genomics. It divides C. trachomatis into clinically and biologically meaningful groups, and may have broad application in surveillance.


Subject(s)
Chlamydia trachomatis/genetics , Chlamydia trachomatis/physiology , DNA, Bacterial/genetics , Evolution, Molecular , Eye/microbiology , Genotyping Techniques , Urogenital System/microbiology , Base Sequence , Computer Simulation , DNA, Bacterial/chemistry , Humans , Nucleic Acid Amplification Techniques , Nucleic Acid Denaturation , Phylogeny , Species Specificity , Transition Temperature
16.
J Antimicrob Chemother ; 73(5): 1242-1246, 2018 05 01.
Article in English | MEDLINE | ID: mdl-29373697

ABSTRACT

Objectives: To identify the genetic basis of resistance as well as to better understand the epidemiology of a recent surge in azithromycin-resistant Neisseria gonorrhoeae in New South Wales, Australia. Methods: Azithromycin-resistant N. gonorrhoeae isolates (n = 118) collected from 107 males, 10 females and 1 transsexual between January and July 2017 were genotyped using a previously described iPLEX method. The results were compared with phenotypic resistance profiles and available patient data. Results: The iPLEX results revealed 10 different N. gonorrhoeae genotypes (designated AZI-G1 to AZI-G10) of which three were responsible for the majority of infections; AZI-G10 (74.6%, 88 isolates; 87 males and 1 transsexual), AZI-G4 (11.0%, 13 isolates; 7 males and 6 females) and AZI-G7 (6.8%, 8 isolates; 7 males and 1 female). The observed resistance was attributable to one of two different azithromycin resistance mechanisms; the 23S rRNA C2611T mutation was identified in 24% of isolates, whereas the majority of resistance (76%) was associated with a meningococcal-type mtrR variant. Additionally, one isolate was found to harbour both the 23S rRNA C2611T mutation and a type XXXIV mosaic penA sequence associated with cephalosporin resistance. Conclusions: These data indicate outbreaks of azithromycin-resistant gonococci amongst networks of MSM and heterosexuals in New South Wales. The results also provide further evidence that azithromycin may soon be an ineffective treatment option for gonococcal infection and highlight the urgent need to explore alternative therapies.


Subject(s)
Anti-Bacterial Agents/pharmacology , Azithromycin/pharmacology , Disease Outbreaks , Drug Resistance, Bacterial , Gonorrhea/epidemiology , Gonorrhea/microbiology , Neisseria gonorrhoeae/drug effects , Adolescent , Adult , Bacterial Proteins , Female , Genotype , Genotyping Techniques , Heterosexuality , Homosexuality, Male , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Neisseria gonorrhoeae/genetics , Neisseria gonorrhoeae/isolation & purification , New South Wales/epidemiology , Point Mutation , RNA, Ribosomal, 23S/genetics , Repressor Proteins , Transgender Persons , Young Adult
17.
Sci Rep ; 8(1): 1503, 2018 01 24.
Article in English | MEDLINE | ID: mdl-29367612

ABSTRACT

Increasing rates of gonorrhoea have been observed among women within the Australian state of New South Wales. Here, we applied whole genome sequencing (WGS) to better understand the associated networks and transmission dynamics. Ninety-four isolates of a particular N. gonorrhoeae genotype (G122) associated with women (years 2012 to 2014) underwent phylogenetic analysis using core single nucleotide polymorphisms. WGS data revealed five main clusters, all of which were heterogeneous in terms of patient age and site of infection. The relatively high cervical/vaginal infections in each cluster was indicative of transmission in the general heterosexual population, noting that there is typically high rates of condom use for vaginal sex among local commercial sex workers. WGS also enabled the identification of groups of individuals belonging to tighter transmission chains within clusters, and hence may present a new tool for targeting public health interventions. The enhanced resolution of WGS provides a ready means of confirming suspected changes in N. gonorrhoeae epidemiology, but also enables key features to be identified or new questions to be raised regarding the composition of the associated sexual networks.


Subject(s)
Disease Transmission, Infectious , Genetic Variation , Genotyping Techniques , Gonorrhea/epidemiology , Neisseria gonorrhoeae/classification , Neisseria gonorrhoeae/genetics , Whole Genome Sequencing , Cities/epidemiology , Cluster Analysis , Female , Genotype , Gonorrhea/microbiology , Gonorrhea/transmission , Humans , Molecular Epidemiology , Neisseria gonorrhoeae/isolation & purification , New South Wales/epidemiology , Phylogeny
18.
BMC Pulm Med ; 17(1): 138, 2017 Nov 02.
Article in English | MEDLINE | ID: mdl-29096618

ABSTRACT

BACKGROUND: Pulmonary exacerbations in cystic fibrosis (CF) remain poorly understood and treatment is usually targeted at Pseudomonas aeruginosa. Within Australia a predominant shared P. aeruginosa strain (AUST-02) is associated with greater treatment needs. This single centre study assessed temporal shared strain population dynamics during and after antibiotic treatment of exacerbations. METHODS: Sputum was collected from 12 adult patients with a history of chronic AUST-02 infection at four time-points during and after treatment of an exacerbation. Forty-eight P. aeruginosa isolates within each sample underwent AUST-02 allele-specific PCR and SNP-based strain genotyping. RESULTS: Various commonly shared Australian strains (AUST-01, 0.1%; AUST-02, 54.3%; AUST-06, 36.6%; AUST-07, 4.6%; AUST-11, 4.3%) and two unique strains (0.1%) were identified from 45 sputum samples (2160 isolates). Based on within-patient relative abundance of strains, a "single-strain infection" (n = 7) or "mixed-strain infection" (n = 5) was assigned to each patient. A significant temporal variation in the P. aeruginosa population composition was found for those with mixed-strain infection (P < 0.001). Patients with mixed-strain infections had more long-term treatment requirements than those with single-strain infection. Moreover, despite both groups having similar lung function at study entry, patients with single-strain infection had greater improvement in FEV1% predicted following their exacerbation treatment (P = 0.02). CONCLUSION: Pulmonary exacerbations may reveal multiple, unrelated P. aeruginosa strains whose relative abundance with one another may change rapidly, in a sustained and unpredictable manner.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Cystic Fibrosis/complications , Pseudomonas Infections/drug therapy , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/genetics , Respiratory Tract Infections/drug therapy , Respiratory Tract Infections/microbiology , Adult , Disease Progression , Female , Forced Expiratory Volume , Genotype , Humans , Male , Middle Aged , Phenotype , Population Dynamics , Pseudomonas Infections/physiopathology , Pseudomonas aeruginosa/isolation & purification , Respiratory Tract Infections/physiopathology , Sputum/microbiology , Time Factors
19.
J Med Microbiol ; 66(10): 1451-1453, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28893363

ABSTRACT

The macrolide azithromycin is recommended for treatment of Mycoplasma genitalium infection; however, M. genitalium strains possessing macrolide resistance-mediating mutations (MRMMs) are increasingly being reported. Here, we used the SpeeDx ResistancePlus MG kit, which provides simultaneous detection of M. genitalium and MRMMs, to assess MRMM carriage among M. genitalium infections in Queensland, Australia. Performance characteristics of the ResistancePlus MG kit for M. genitalium detection were compared to in-house PCR. Available M. genitalium PCR-positive (n=67) and negative (n=281) samples from the years 2011 to 2017 were tested using the SpeeDx ResistancePlus MG kit. In total, 63.6 % M. genitalium-positive samples were indicated to harbour MRMMs. The ResistancePlus MG method provided sensitivity and specificity of 97 and 99.6 % respectively compared to in-house PCR for M. genitalium detection. Such high levels of macrolide-resistant M. genitalium raise further concerns over future use of azithromycin for treatment of M. genitalium infection.


Subject(s)
Anti-Bacterial Agents/pharmacology , Azithromycin/pharmacology , Macrolides/pharmacology , Mycoplasma Infections/epidemiology , Mycoplasma Infections/microbiology , Mycoplasma genitalium/drug effects , Female , Humans , Male , Queensland/epidemiology
20.
Emerg Infect Dis ; 23(9): 1478-1485, 2017 09.
Article in English | MEDLINE | ID: mdl-28820128

ABSTRACT

Neisseria gonorrhoeae antimicrobial resistance (AMR) is a globally recognized health threat; new strategies are needed to enhance AMR surveillance. The Northern Territory of Australia is unique in that 2 different first-line therapies, based primarily on geographic location, are used for gonorrhea treatment. We tested 1,629 N. gonorrhoeae nucleic acid amplification test-positive clinical samples, collected from regions where ceftriaxone plus azithromycin or amoxicillin plus azithromycin are recommended first-line treatments, by using 8 N. gonorrhoeae AMR PCR assays. We compared results with those from routine culture-based surveillance data. PCR data confirmed an absence of ceftriaxone resistance and a low level of azithromycin resistance (0.2%), and that penicillin resistance was <5% in amoxicillin plus azithromycin regions. Rates of ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae were lower when molecular methods were used. Molecular methods to detect N. gonorrhoeae AMR can increase the evidence base for treatment guidelines, particularly in settings where culture-based surveillance is limited.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Drug Resistance, Bacterial/genetics , Gonorrhea/epidemiology , Neisseria gonorrhoeae/genetics , Public Health Surveillance , Adult , Amoxicillin/therapeutic use , Azithromycin/therapeutic use , Ceftriaxone/therapeutic use , Ciprofloxacin/therapeutic use , Female , Gonorrhea/drug therapy , Gonorrhea/microbiology , Gonorrhea/transmission , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Epidemiology , Multilocus Sequence Typing , Neisseria gonorrhoeae/drug effects , Neisseria gonorrhoeae/isolation & purification , Northern Territory/epidemiology , Penicillins/therapeutic use
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