Lack of effectiveness of 13-valent pneumococcal conjugate vaccination against pneumococcal carriage density in Papua New Guinean infants
- Authors: Britton, Kathryn , Pickering, Janessa , Pomat, William , de Gier, Camilla , Greenhill, Andrew
- Date: 2021
- Type: Text , Journal article
- Relation: Vaccine Vol. 39, no. 38 (2021), p. 5401-5409
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- Description: Background: Papua New Guinea (PNG) introduced the 13-valent pneumococcal conjugate vaccine (PCV13) in 2014, with administration at 1, 2, and 3 months of age. PCV13 has reduced or eliminated carriage of vaccine types in populations with low pneumococcal carriage prevalence, carriage density and serotype diversity. This study investigated PCV13 impact on serotype-specific pneumococcal carriage prevalence, density, and serotype diversity in PNG infants, who have some of the highest reported rates of pneumococcal carriage and disease in the world. Methods: Nasopharyngeal swabs were collected at 1, 4 and 9 months of age from PCV13-vaccinated infants (n = 57) and age-/season-matched, unvaccinated infants (at approximately 1 month, n = 53; 4 months, n = 57; 9 months, n = 52). Serotype-specific pneumococcal carriage density and antimicrobial resistance genes were identified by qPCR and microarray. Results: Pneumococci were present in 89% of swabs, with 60 different serotypes and four non-encapsulated variants detected. Multiple serotype carriage was common (47% of swabs). Vaccine type carriage prevalence was similar between PCV13-vaccinated and unvaccinated infants at 4 and 9 months of age. The prevalence of non-vaccine type carriage was also similar between cohorts, with non-vaccine types present in three-quarters of samples (from both vaccinated and unvaccinated infants) by 4 months of age. The median pneumococcal carriage density was high and similar at each age group (~7.0 log10 genome equivalents/mL). PCV13 had no effect on overall pneumococcal carriage density, vaccine type density, non-vaccine type density, or the prevalence of antimicrobial resistance genes. Conclusion: PNG infants experience dense and diverse pneumococcal colonisation with concurrent serotypes from 1 month of age. PCV13 had no impact on pneumococcal carriage density, even for vaccine serotypes. The low prevalence of vaccine serotypes, high pneumococcal carriage density and abundance of non-vaccine serotypes likely contribute to the lack of PCV13 impact on carriage in PNG infants. Indirect effects of the infant PCV programs are likely to be limited in PNG. Alternative vaccines with broader coverage should be considered. © 2021 The Authors. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Andrew Greenhill" is provided in this record**
Gut microbiota composition in obese and non-obese adult relatives from the highlands of Papua New Guinea
- Authors: Jonduo, Marinjho , Wawae, Lorry , Masiria, Geraldine , Suda, Wataru , Hattori, Masahira , Takayasu, Lena , Abdad, Mohammad , Greenhill, Andrew , Horwood, Paul , Pomat, William , Umezaki, Masahiro
- Date: 2020
- Type: Text , Journal article
- Relation: FEMS microbiology letters Vol. 367, no. 19 (2020), p.
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- Description: Obesity is a condition that results from an imbalance between energy intake and expenditure. Recently, obesity has been linked to differences in the composition of gut microbiota. To examine this association in Papua New Guinea (PNG) highlanders, fecal samples were collected from 18 adults; nine obese participants were paired with their non-obese relative. Amplification of the 16S rRNA gene targeting the V1-V2 region was performed on DNA extracts for each participant, with high-quality sequences selected and used for operational taxonomic unit clustering. The data showed Firmicutes and Bacteroidetes were the two dominant phyla, while at genus level Prevotella was the most dominant genus in all of the samples. Nonetheless, statistical evaluation of potential association between nutritional status and bacterial abundance at both phyla and genus levels showed no significant difference. Further studies, ideally in both rural and urban areas, are needed to evaluate the role of the gut microbiome in the occurrence of obesity in PNG and other resource-limited settings. © The Author(s) 2020. Published by Oxford University Press on behalf of FEMS.
Safety and immunogenicity of pneumococcal conjugate vaccines in a high-risk population : A randomized controlled trial of 10-valent and 13-valent pneumococcal conjugate vaccine in Papua New Guinean infants
- Authors: Pomat, William , Van Den Biggelaar, Anita , Wana, Sandra , Francis, Jacinta , Solomon, Vela , Greenhill, Andrew , Ford, Rebecca , Orami, Tilda , Passey, Megan , Jacoby, Peter , Kirkham, Lea-Ann , Lehmann, Deborah , Richmond, Peter
- Date: 2019
- Type: Text , Journal article
- Relation: Clinical Infectious Diseases Vol. 68, no. 9 (2019), p. 1472-1481
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- Description: Background. There are little data on the immunogenicity of PCV10 and PCV13 in the same high-risk population. Methods. PCV10 and PCV13 were studied head-to-head in a randomized controlled trial in Papua New Guinea in which 262 infants received 3 doses of PCV10 or PCV13 at 1, 2, and 3 months of age. Serotype-specific immunoglobulin G (IgG) concentrations, and pneumococcal and nontypeable Haemophilus influenzae (NTHi) carriage were assessed prevaccination and at 4 and 9 months of age. Infants were followed up for safety until 9 months of age. Results. One month after the third dose of PCV10 or PCV13, 80% of infants had IgG concentrations ≥0.35µg/mL for vaccine serotypes, and 6 months postvaccination IgG concentrations ≥0.35 µg/mL were maintained for 8/10 shared PCV serotypes in > 75% of children vaccinated with either PCV10 or PCV13. Children carried a total of 65 different pneumococcal serotypes (plus nonserotypeable). At 4 months of age, 92% (95% confidence interval [CI] 85–96) of children vaccinated with PCV10 and 81% (95% CI 72–88) vaccinated with PCV13 were pneumococcal carriers (P = .023), whereas no differences were seen at 9 months of age, or for NTHi carriage. Both vaccines were well tolerated and not associated with serious adverse events. Conclusions. Infant vaccination with 3 doses of PCV10 or PCV13 is safe and immunogenic in a highly endemic setting; however, to significantly reduce pneumococcal disease in these settings, PCVs with broader serotype coverage and potency to reduce pneumococcal carriage are needed. Clinical Trials Registration. NCT01619462.
Influenza A(H5N1) viruses with A(H9N2) single gene (matrix or PB1) reassortment isolated from Cambodian live bird markets
- Authors: Suttie, Annika , Karlsson, Erik , Deng, Yi-Mo , Horm, Srey , Yann, Sokhoun , Tok, Songha , Sorn, San , Holl, Davun , Tum, Sothyra , Hurt, Aeron , Greenhill, Andrew , Barr, Ian , Horwood, Paul , Dussart, Philippe
- Date: 2018
- Type: Text , Journal article
- Relation: Virology Vol. 523, no. (2018), p. 22-26
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- Description: Live bird market surveillance for avian influenza viruses in Cambodia in 2015 has led to the detection of two 7:1 reassortant influenza A(H5N1) clade 2.3.2.1c viruses. These reassortant strains, designated A/duck/Cambodia/Z564W35M1/2015 and A/chicken/Cambodia/Z850W49M1/2015, both contained a single gene (PB1 and matrix gene, respectively) from concurrently circulating A(H9N2) influenza viruses. All other viral genes from both isolates clustered with A(H5N1) clade 2.3.2.1 viruses. Continued and prolonged co-circulation of influenza A(H5N1) and A(H9N2) viruses in Cambodian live bird markets may present a risk for the emergence of novel influenza reassortant viruses with negative agricultural and/or public health implications. © 2018
A high burden of asymptomatic gastrointestinal infections in traditional communities in Papua New Guinea
- Authors: Horwood, Paul , Soli, Kevin , Maure, Tobias , Naito, Yuichi , Morita, Ayako , Natsuhara, Kazumi , Tadokoro, Kiyoshi , Baba, Jun , Odani, Shingo , Tomitsuka, Eriko , Igai, Katsura , Larkins, Jo-Ann , Siba, Peter , Pomat, William , McBryde, Emma , Umezaki, Masahiro , Greenhill, Andrew
- Date: 2017
- Type: Text , Journal article
- Relation: American Journal of Tropical Medicine and Hygiene Vol. 97, no. 6 (2017), p. 1872-1875
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- Description: Stool samples were collected from 148 healthy adults living a traditional subsistence lifestyle in Papua New Guinea and screened for enteric pathogens using real-time RT-PCR/PCR assays. Enteric pathogens were detected in a high proportion (41%) of individuals. Clear differences were observed in the detection of pathogens between highland and lowland communities. In particular, there was a marked difference in detection rates of norovirus GII (20% and 0%, respectively) and Shigella sp. (15% and 0%, respectively). Analysis of the relationship between enteric pathogen carriage and microbial community composition of participants, using box plots to compare specific normal flora population numbers, did not suggest that gut microbial composition was directly associated with pathogen carriage. This study suggests that enteric pathogens are common in healthy individuals in Papua New Guinean highland communities, presumably acting as a reservoir of infection and thus contributing to a high burden of gastrointestinal illnesses.
Shigellosis : A truly neglected disease in Papua New Guinea
- 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
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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.
Impact of intermittent preventive treatment in pregnancy with azithromycin-containing regimens on maternal nasopharyngeal carriage and antibiotic sensitivity of Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus : A cross-sectional survey at delivery
- Authors: Unger, Holger , Aho, Celestine , Ome-Kaius, Maria , Wangnapi, Regina , Umbers, Alexandra , Jack, Wanda , Lafana, Alice , Michael, Audrey , Hanieh, Sarah , Siba, Peter , Mueller, Ivo , Greenhill, Andrew , Rogerson, Stephen
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Clinical Microbiology Vol. 53, no. 4 (2015), p. 1317-1323
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- Description: Sulfadoxine-pyrimethamine (SP) plus azithromycin (AZ) (SPAZ) has the potential for intermittent preventive treatment of malaria in pregnancy (IPTp), but its use could increase circulation of antibiotic-resistant bacteria associated with severe pediatric infections. We evaluated the effect of monthly SPAZ-IPTp compared to a single course of SP plus chloroquine (SPCQ) on maternal nasopharyngeal carriage and antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus at delivery among 854 women participating in a randomized controlled trial in Papua New Guinea. Serotyping was performed, and antibiotic susceptibility was evaluated by disk diffusion and Etest. Potential risk factors for carriage were examined. Nasopharyngeal carriage at delivery of S. pneumoniae (SPAZ, 7.2% [30/418], versus SPCQ, 19.3% [84/436]; P < 0.001) and H. influenzae (2.9% [12/418] versus 6.0% [26/436], P = 0.028), but not S. aureus, was significantly reduced among women who had received SPAZ-IPTp. The number of macrolide-resistant pneumococcal isolates was small but increased in the SPAZ group (13.3% [4/30], versus SPCQ, 2.2% [2/91]; P = 0.033). The proportions of isolates with serotypes covered by the 13-valent pneumococcal conjugate vaccine were similar (SPAZ, 10.3% [3/29], versus SPCQ, 17.6% [16/91]; P = 0.352). Although macrolide-resistant isolates were rare, they were more commonly detected in women who had received SPAZ-IPTp, despite the significant reduction of maternal carriage of S. pneumoniae and H. influenzae observed in this group. Future studies on SPAZ-IPTp should evaluate carriage and persistence of macrolide-resistant S. pneumoniae and other pathogenic bacteria in both mothers and infants and assess the clinical significance of their circulation.
The PneuCarriage Project : A multi-centre comparative study to identify the best serotyping methods for examining pneumococcal carriage in vaccine evaluation studies
- Authors: Satzke, Catherine , Dunne, Eileen , Porter, Barbara , Klugman, Keith , Mulholland, Kim , PneuCarriage project group , Greenhill, Andrew
- Date: 2015
- Type: Text , Journal article
- Relation: PLoS Medicine Vol. 12, no. 11 (2015), p. 1-30
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- Description: Background: The pneumococcus is a diverse pathogen whose primary niche is the nasopharynx. Over 90 different serotypes exist, and nasopharyngeal carriage of multiple serotypes is common. Understanding pneumococcal carriage is essential for evaluating the impact of pneumococcal vaccines. Traditional serotyping methods are cumbersome and insufficient for detecting multiple serotype carriage, and there are few data comparing the new methods that have been developed over the past decade. We established the PneuCarriage project, a large, international multi-centre study dedicated to the identification of the best pneumococcal serotyping methods for carriage studies. Methods and Findings: Reference sample sets were distributed to 15 research groups for blinded testing. Twenty pneumococcal serotyping methods were used to test 81 laboratory-prepared (spiked) samples. The five top-performing methods were used to test 260 nasopharyngeal (field) samples collected from children in six high-burden countries. Sensitivity and positive predictive value (PPV) were determined for the test methods and the reference method (traditional serotyping of >100 colonies from each sample). For the alternate serotyping methods, the overall sensitivity ranged from 1% to 99% (reference method 98%), and PPV from 8% to 100% (reference method 100%), when testing the spiked samples. Fifteen methods had ≥70% sensitivity to detect the dominant (major) serotype, whilst only eight methods had ≥70% sensitivity to detect minor serotypes. For the field samples, the overall sensitivity ranged from 74.2% to 95.8% (reference method 93.8%), and PPV from 82.2% to 96.4% (reference method 99.6%). The microarray had the highest sensitivity (95.8%) and high PPV (93.7%). The major limitation of this study is that not all of the available alternative serotyping methods were included. Conclusions: Most methods were able to detect the dominant serotype in a sample, but many performed poorly in detecting the minor serotype populations. Microarray with a culture amplification step was the top-performing method. Results from this comprehensive evaluation will inform future vaccine evaluation and impact studies, particularly in low-income settings, where pneumococcal disease burden remains high. © 2015 Satzke et al. *For a complete list of authors, please see acknowledgments in the published article.
Cholera in Papua New Guinea : Observations to date and future considerations
- Authors: Horwood, Paul , Greenhill, Andrew
- Date: 2013
- Type: Text , Journal article
- Relation: Papua and New Guinea Medical Journal Vol. 56, no. 3-4 (2013), p. 162-165
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- Description: Cholera is a severe diarrhoeal illness caused by infection with the bacterium Vibrio cholerae. From July 2009 to late 2011 Papua New Guinea (PNG) experienced thefirst outbreak of cholera ever reported in this country. During this time > 15,000 cases of cholera were reported, resulting in approximately 500 deaths. The origin of this outbreak is unknown, but considering the remote location of the initial outbreak an infected international traveller is unlikely to be the source. In this paper we review the characteristics of the PNG cholera outbreak and discuss the ongoing threat of cholera to the country and the region.
Evaluation of a rapid immunochromatographic assay for the detection of rotavirus, norovirus and adenovirus from children hospitalized with acute watery diarrhea
- Authors: Kas, Monalisa , Maure, Tobias , Soli, Kevin , Umezaki, Masahiro , Morita, Ayako , Bebes, Sauli , Jonduo, Marinjho , Larkins, Jo-Ann , Luang-Suarkia, Dagwin , Siba, Peter , Greenhill, Andrew , Horwood, Paul
- Date: 2013
- Type: Text , Journal article
- Relation: Papua and New Guinea Medical Journal Vol. 56, no. 3-4 (2013), p. 141-144
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- Description: We evaluated the IP-Triple I immunochromatographic rapid test for the detection of rotavirus, norovirus and adenovirus using stool samples from children with diarrhoea. The detection of norovirus and adenovirus was poor compared to polymerase chain reaction assays. However, high sensitivity (92%) and specificity (99%) were obtained for the detection of rotavirus.
Evaluation of a WASH intervention demonstrates the potential for improved hygiene practices in Hiri District, Central Province
- Authors: Phuanukoonnon, Suparat , Namosha, Elias , Kua, Lydia , Siba, Peter , Greenhill, Andrew
- Date: 2013
- Type: Text , Journal article
- Relation: Papua and New Guinea medical journal Vol. 56, no. 3-4 (2013), p. 126-135
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- Description: Water, sanitation and hygiene (WASH) interventions aim to improve health outcomes through provision of safe water supplies and improved sanitation facilities, while also promoting better hygiene practices in communities. Population Services International introduced a WASH intervention project in the Hiri District, Central Province in May 2012. Shortly after its introduction we conducted a survey to determine the uptake of the intervention and gauge its impact. We invited 400 households to participate in the study, which consisted of a questionnaire for the head of the household. A total of 395 questionnaires were completed: 314 from households that had participated in the WASH intervention and 81 that had not (controls). Results demonstrated that improved water sources were not routinely used, with a high dependence on well and surface water. While self-reported handwashing was common, use of soap was not common. Treatment of water inside the house was common in the intervention group (95%), compared to 49% in the non-WASH group. The study indicates that people in the Hiri District are supportive of a WASH intervention, with good uptake of some aspects of the intervention. The sustainability of the intervention remains unknown. Targetted interventions focusing on community priorities might be beneficial in the future.
Isolation of Vibrio cholerae and other enteric microbiota from patients with suspected cholera during the 2009 outbreak in Madang Province, Papua New Guinea
- Authors: Kas, Monalisa , Horwood, Paul , Laman, Moses , Manning, Laurens , Atua, Vincent , Siba, Peter , Greenhill, Andrew
- Date: 2013
- Type: Text , Journal article
- Relation: Papua and New Guinea medical journal Vol. 56, no. 3-4 (2013), p. 110-115
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- Description: When cholera was first detected in Papua New Guinea (PNG) in mid-2009, national diagnostic capacity faced many challenges. This was in part due to the non-endemic status of the outbreak, resulting in few local staff experienced in Vibrio cholerae detection and poor access to the required consumables. The PNG Institute of Medical Research conducted culture on specimens from suspected cholera patients in Madang Province, with presumptive V. cholerae isolates sent to Goroka for confirmation. Of 98 samples analysed 15 were culture positive, with V. cholerae detected by polymerase chain reaction (PCR) in an additional 3 samples. Further analyses were conducted to identify other pathogenic bacteria from thiosulphate citrate bile salt sucrose (TCBS) agar. Molecular-based assays detected enteropathogenic (n = 1) and enterotoxigenic (n = 1) strains of Escherichia coli. No other major enteric pathogens were detected. The low detection rate of V. cholerae at the provincial level reflects challenges in the laboratory diagnosis of cholera and in-country challenges in responding to an outbreak of a non-endemic disease, such as lack of in-country diagnostic expertise and available consumables in the early stages. It also suggests that full aetiological investigations are warranted in future outbreaks of acute watery diarrhoea in PNG to fully elucidate the potentially complex aetiology, which could in turn guide diagnostic, treatment and prevention measures.
Sago haemolytic disease : Towards understanding a novel food-borne toxicosis
- Authors: Shipton, Warren , Greenhill, Andrew , Warner, Jeffrey
- Date: 2013
- Type: Text , Journal article
- Relation: Papua and New Guinea medical journal Vol. 56, no. 3-4 (2013), p. 166-177
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- Description: Sago haemolytic disease is a rare but sometimes fatal disease found primarily in the coastal regions of Papua New Guinea and among groups in which sago is a primary source of carbohydrate. It has been known since 1961 and fungi consistently have been suspected of being involved. Investigations carried out on stored sago and samples recovered from poisoning episodes have failed to indicate the consistent presence of mycotoxins. However, fungi (especially Aspergillus, Fusarium, Penicillium, Trichoderma) with strong haemolytic activity have been associated with sago, particularly when stored in open-weave baskets and sago-leaf-wrapped bundles. The haemolytic activity has been attributed to fatty acids (principally oleic, palmitic, linoleic) contained primarily in the fungal hyphae. It is hypothesized that when these acids are released through hyphal breakdown during digestion and are present in individuals with a low serum albumin level, free fatty acid excess occurs resulting in red cell membrane destruction and intravascular haemolysis. In extreme cases, blood transfusion is required. Methods of storage providing high levels of access to oxygen favour the development of fungi: eg, leaf-encased bundles and open-weave storage favour growth over that seen in starch stored under water, such as in earthen vessels. Ensuring storage does not exceed 3-4 weeks, encouraging anaerobic conditions of the starch and maintaining protein nutrition in communities where sago is relied upon should alleviate outbreak episodes.
Bloodstream infections caused by resistant bacteria in surgical patients admitted to Modilon Hospital, Madang
- Authors: Asa, Henao , Laman, Moses , Greenhill, Andrew , Siba, Peter , Davis, Timothy , Maihua, John , Manning, Laurens
- Date: 2012
- Type: Text , Journal article
- Relation: Papua and New Guinea Medical Journal Vol. 55, no. 1-4 (2012), p. 5-11
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- Description: In view of the dearth of information relating to antibiotic resistance in community- and hospital-acquired bacterial infections in Papua New Guinea (PNG), we carried out a prospective, hospital-based observational study of surgical patients between October 2008 and October 2009. In a sample of 115 patients (median age 30 years; 55% males) suspected of having a bloodstream infection, blood cultures were positive in 11 (10%) and a significant pathogen was isolated in 9 (8%). Staphylococcus aureus was isolated in 4 patients (44%) and 3 were methicillin resistant; all these isolates were considered community acquired because cultures were performed within 48 hours of admission. Of the remaining 5 isolates, 4 were Gram-negative organisms with at least intermediate resistance to chloramphenicol that were grown from blood taken > 48 hours post-admission and thus considered nosocomially acquired. These data suggest two distinct patterns of bacterial infection in PNG surgical inpatients that have implications for national antibiotic prescription guidelines.
Predictors of acute bacterial meningitis in children from a malaria-endemic area of Papua New Guinea
- Authors: Laman, Moses , Manning, Laurens , Greenhill, Andrew , Mare, Trevor , Michael, Audrey , Shem, Silas , Vince, John , Lagani, William , Hwaihwanje, Ilomo , Siba, Peter , Mueller, Ivo , Davis, Timothy
- Date: 2012
- Type: Text , Journal article
- Relation: American Journal of Tropical Medicine and Hygiene Vol. 86, no. 2 (2012), p. 240-245
- Full Text: false
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- Description: Predictors of acute bacterial meningitis (ABM) were assessed in 554 children in Papua New Guinea 0.2-10 years of age who were hospitalized with culture-proven meningitis, probable meningitis, or non-meningitic illness investigated by lumbar puncture. Forty-seven (8.5%) had proven meningitis and 36 (6.5%) had probable meningitis. Neck stiffness, Kernig's and Brudzinski's signs and, in children < 18 months of age, a bulging fontanel had positive likelihood ratios (LRs) ≥ 4.3 for proven/probable ABM. Multiple seizures and deep coma were less predictive (LR = 1.5-2.1). Single seizures and malaria parasitemia had low LRs (≤ 0.5). In logistic regression including clinical variables, Kernig's sign and deep coma were positively associated with ABM, and a single seizure was negatively associated (P ≤ 0.01). In models including microscopy, neck stiffness and deep coma were positively associated with ABM and parasitemia was negatively associated with ABM (P ≤ 0.04). In young children, a bulging fontanel added to the model (P < 0.001). Simple clinical features predict ABM in children in Papua New Guinea but malaria microscopy augments diagnostic precision.
Multilocus sequence typing of Streptococcus pneumoniae by use of mass spectrometry
- Authors: Dunne, Eileen , Ong, Engkok , Moser, Ralf , Siba, Peter , Phuanukoonnon, Suparat , Greenhill, Andrew , Robins-Browne, Roy , Mulholland, Edward , Satzke, Catherine
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Clinical Microbiology Vol. 49, no. 11 (2011), p. 3756-3760
- Full Text: false
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- Description: Multilocus sequence typing (MLST) is an important tool for the global surveillance of bacterial pathogens that is performed by comparing the sequences of designated housekeeping genes. We developed and tested a novel mass spectrometry-based method for MLST of Streptococcus pneumoniae. PCR amplicons were subjected to in vitro transcription and base-specific cleavage, followed by analysis of the resultant fragments by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Comparison of the cleavage fragment peak patterns to a reference sequence set permitted automated identification of alleles. Validation experiments using 29 isolates of S. pneumoniae revealed that the results of MALDI-TOF MS MLST matched those obtained by traditional sequence-based MLST for 99% of alleles and that the MALDITOF MS method accurately identified two single-nucleotide variations. The MADLI-TOF MS method was then used for MLST analysis of 43 S. pneumoniae isolates from Papua New Guinean children. The majority of the isolates present in this population were not clonal and contained seven new alleles and 30 previously unreported sequence types.