Antimicrobial sensitivity trends and virulence genes in Shigella spp. from the Oceania region
- Malau, Elisheba, Ford, Rebecca, Valcanis, Mary, Jennison, Amy, Mosse, Jenny, Bean, David, Yoannes, Mition, Pomat, William, Horwood, Paul, Greenhill, Andrew
- Authors: Malau, Elisheba , Ford, Rebecca , Valcanis, Mary , Jennison, Amy , Mosse, Jenny , Bean, David , Yoannes, Mition , Pomat, William , Horwood, Paul , Greenhill, Andrew
- Date: 2018
- Type: Text , Journal article
- Relation: Infection, Genetics and Evolution Vol. 64, no. (2018), p. 52-56
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- Reviewed:
- Description: Shigella is a common cause of diarrhoea in Papua New Guinea (PNG) and other Oceania countries. However, little is known about the strains causing infection. Archived Shigella isolates (n = 72) were obtained from research laboratories in PNG and reference laboratories in Australia. Shigella virulence genes were detected by PCR, and antimicrobial susceptibility was determined by disk diffusion. The ipaH virulence gene was present in all 72 isolates. The prevalence of other virulence genes was variable, with ial, invE, ipaBCD, sen/ospD3 and virF present in 60% of isolates and set1A and set1B genes present in 42% of isolates. Most S. flexneri isolates contained genes encoding enterotoxin 1 and/or enterotoxin 2. Resistance to antibiotics was common, with 51/72 isolates resistant to 2–4 antimicrobials. A greater proportion of bacteria isolated since 2010 (relative to pre-2010 isolates) were resistant to commonly used antibiotics such as ampicillin, chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole; suggesting that antimicrobial resistance (AMR) in Shigella is increasing over time in the Oceania region. There is a need for improved knowledge regarding Shigella circulation in the Oceania region and further monitoring of AMR patterns. © 2018 Elsevier B.V.
- Authors: Malau, Elisheba , Ford, Rebecca , Valcanis, Mary , Jennison, Amy , Mosse, Jenny , Bean, David , Yoannes, Mition , Pomat, William , Horwood, Paul , Greenhill, Andrew
- Date: 2018
- Type: Text , Journal article
- Relation: Infection, Genetics and Evolution Vol. 64, no. (2018), p. 52-56
- Full Text:
- Reviewed:
- Description: Shigella is a common cause of diarrhoea in Papua New Guinea (PNG) and other Oceania countries. However, little is known about the strains causing infection. Archived Shigella isolates (n = 72) were obtained from research laboratories in PNG and reference laboratories in Australia. Shigella virulence genes were detected by PCR, and antimicrobial susceptibility was determined by disk diffusion. The ipaH virulence gene was present in all 72 isolates. The prevalence of other virulence genes was variable, with ial, invE, ipaBCD, sen/ospD3 and virF present in 60% of isolates and set1A and set1B genes present in 42% of isolates. Most S. flexneri isolates contained genes encoding enterotoxin 1 and/or enterotoxin 2. Resistance to antibiotics was common, with 51/72 isolates resistant to 2–4 antimicrobials. A greater proportion of bacteria isolated since 2010 (relative to pre-2010 isolates) were resistant to commonly used antibiotics such as ampicillin, chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole; suggesting that antimicrobial resistance (AMR) in Shigella is increasing over time in the Oceania region. There is a need for improved knowledge regarding Shigella circulation in the Oceania region and further monitoring of AMR patterns. © 2018 Elsevier B.V.
Shigellosis : A truly neglected disease in Papua New Guinea
- Malau, Elisheba, Mosse, Jenny, Horwood, Paul, Greenhill, Andrew
- Authors: Malau, Elisheba , Mosse, Jenny , Horwood, Paul , Greenhill, Andrew
- Date: 2016
- Type: Text , Journal article
- Relation: Papua New Guinea Medical Journal Vol. 59, no. 3/4 (2016), p. 147-154
- Full Text: false
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- Description: Diarrhoeal diseases still affect many people, especially children living in impoverished and under-developed settings. In Papua New Guinea (PNG) diarrhoea remains one of the leading causes of hospitalization and a major cause of death. Here, we focus on the role of Shigella in diarrhoeal illness in PNG, and provide an overview of the causative organism and the illness. A review of the available data on the aetiology of diarrhoea in PNG suggests that shigellosis is a major cause of diarrhoeal illness. Since shigellosis can cause protracted and life-threatening illness an appreciation of the burden of shigellosis is important to aid in the development of optimal prevention and control strategies. Treatment strategies for all cases of moderate-severe diarrhoeal illness should centre on rehydration, but where antimicrobial treatment is required consideration should be given to the increasing antimicrobial resistance observed in Shigella isolates in PNG.
The molecular characterisation of shigella spp. from Papua New Guinea and Pacific Island Nations
- Authors: Malau, Elisheba
- Date: 2019
- Type: Text , Thesis , PhD
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- Description: In Papua New Guinea (PNG) and other low-middle income countries (LMICs) in Oceania, diarrhoea remains a leading cause of hospitalisation and death in children <5 years old; and is an important cause of illness in older children and adults. Shigella is one of four leading causes of diarrhoea globally and is likely a major cause of diarrhoea in Oceanic LMICs, particularly PNG. A survey was conducted among parents of children with diarrhoea in the PNG highlands, demonstrating limited access to, and application of, sanitation and hygiene; likely contributing to the transmission of Shigella and other pathogens in PNG. To better understand Shigella in Oceanic LMICs, multiple analyses of isolates from within PNG (n=38), far-northeastern Australia, and from travellers returning to Australia from Oceanic LMICs with shigellosis (n=34) were conducted. Antimicrobial susceptibility (by disc diffusion), detection of virulence genes by polymerase chain reaction (PCR) were conducted on all isolates, and whole genome sequencing (WGS) conducted on 63 isolates. Shigella spp. were commonly resistant to two or more classes of first-line antibiotics, with resistance more common in post-2010 relative to pre-2010 isolates. WGS was used to verify PCR detection of virulence genes, determine whether resistance could be predicted genetically, and conduct phylogenetic analysis of Shigella spp. in Oceania. WGS surpassed PCR in the detection of virulence genes, but correlated poorly with phenotypic antimicrobial resistance. Phylogenetic analysis revealed the intra- and inter-country relatedness. Three phylogenetic groups of S. flexneri co-exist in Oceanic LMICs (and far-northeastern Australia), the result of multiple incursions. Two lineages of S. sonnei were detected, one circulating in PNG and New Caledonia, and the other in various other countries including Fiji; with no geographical overlap of the two S. sonnei lineages. Incursions of Shigella into the Oceanic LMICs occur regularly, and are likely to occur again. This study provides evidence of the need for, and potential approach to, expanded surveillance of Shigella in the region.
- Description: Doctor of Philsophy
- Authors: Malau, Elisheba
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: In Papua New Guinea (PNG) and other low-middle income countries (LMICs) in Oceania, diarrhoea remains a leading cause of hospitalisation and death in children <5 years old; and is an important cause of illness in older children and adults. Shigella is one of four leading causes of diarrhoea globally and is likely a major cause of diarrhoea in Oceanic LMICs, particularly PNG. A survey was conducted among parents of children with diarrhoea in the PNG highlands, demonstrating limited access to, and application of, sanitation and hygiene; likely contributing to the transmission of Shigella and other pathogens in PNG. To better understand Shigella in Oceanic LMICs, multiple analyses of isolates from within PNG (n=38), far-northeastern Australia, and from travellers returning to Australia from Oceanic LMICs with shigellosis (n=34) were conducted. Antimicrobial susceptibility (by disc diffusion), detection of virulence genes by polymerase chain reaction (PCR) were conducted on all isolates, and whole genome sequencing (WGS) conducted on 63 isolates. Shigella spp. were commonly resistant to two or more classes of first-line antibiotics, with resistance more common in post-2010 relative to pre-2010 isolates. WGS was used to verify PCR detection of virulence genes, determine whether resistance could be predicted genetically, and conduct phylogenetic analysis of Shigella spp. in Oceania. WGS surpassed PCR in the detection of virulence genes, but correlated poorly with phenotypic antimicrobial resistance. Phylogenetic analysis revealed the intra- and inter-country relatedness. Three phylogenetic groups of S. flexneri co-exist in Oceanic LMICs (and far-northeastern Australia), the result of multiple incursions. Two lineages of S. sonnei were detected, one circulating in PNG and New Caledonia, and the other in various other countries including Fiji; with no geographical overlap of the two S. sonnei lineages. Incursions of Shigella into the Oceanic LMICs occur regularly, and are likely to occur again. This study provides evidence of the need for, and potential approach to, expanded surveillance of Shigella in the region.
- Description: Doctor of Philsophy
- Dyson, Zoe, Malau, Elisheba, Horwood, Paul, Ford, Rebecca, Siba, Valentine, Yoannes, Mition, Pomat, William, Passey, Megan, Judd, Louise, Ingle, Danielle, Williamson, Deborah, Dougan, Gordon, Greenhill, Andrew, Holt, Kathryn
- Authors: Dyson, Zoe , Malau, Elisheba , Horwood, Paul , Ford, Rebecca , Siba, Valentine , Yoannes, Mition , Pomat, William , Passey, Megan , Judd, Louise , Ingle, Danielle , Williamson, Deborah , Dougan, Gordon , Greenhill, Andrew , Holt, Kathryn
- Date: 2022
- Type: Text , Journal article
- Relation: PLoS Neglected Tropical Diseases Vol. 16, no. 3 (2022), p.
- Full Text: false
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- Description: Background Typhoid fever, a systemic infection caused by Salmonella enterica serovar Typhi, remains a considerable public health threat in impoverished regions within many low-and middle-income settings. However, we still lack a detailed understanding of the emergence, population structure, molecular mechanisms of antimicrobial resistance (AMR), and transmission dynamics of S. Typhi across many settings, particularly throughout the Asia-Pacific islands. Here we present a comprehensive whole genome sequence (WGS) based overview of S. Typhi populations circulating in Papua New Guinea (PNG) over 30 years. Principle findings Bioinformatic analysis of 86 S. Typhi isolates collected between 1980–2010 demonstrated that the population structure of PNG is dominated by a single genotype (2.1.7) that appears to have emerged in the Indonesian archipelago in the mid-twentieth century with minimal evidence of inter-country transmission. Genotypic and phenotypic data demonstrated that the PNG S. Typhi population appears to be susceptible to former first line drugs for treating typhoid fever (chloramphenicol, ampicillin and co-trimoxazole), as well as fluoroquinolones, third generation cephalosporins, and macrolides. PNG genotype 2.1.7 was genetically con-served, with very few deletions, and no evidence of plasmid or prophage acquisition. Genetic variation among this population was attributed to either single point mutations, or homologous recombination adjacent to repetitive ribosomal RNA operons. Significance Antimicrobials remain an effective option for the treatment of typhoid fever in PNG, along with other intervention strategies including improvements to water, sanitation and hygiene (WaSH) related infrastructure and potentially the introduction of Vi-conjugate vaccines. However, continued genomic surveillance is warranted to monitor for the emergence of AMR within local populations, or the introduction of AMR associated genotypes of S. Typhi in this setting. © The Authors.
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