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Morris DE, Cleary DW, Clarke SC. Secondary Bacterial Infections Associated with Influenza Pandemics. Front Microbiol 2017; 8:1041. [PMID: 28690590 PMCID: PMC5481322 DOI: 10.3389/fmicb.2017.01041] [Citation(s) in RCA: 302] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/24/2017] [Indexed: 12/16/2022] Open
Abstract
Lower and upper respiratory infections are the fourth highest cause of global mortality (Lozano et al., 2012). Epidemic and pandemic outbreaks of respiratory infection are a major medical concern, often causing considerable disease and a high death toll, typically over a relatively short period of time. Influenza is a major cause of epidemic and pandemic infection. Bacterial co/secondary infection further increases morbidity and mortality of influenza infection, with Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus reported as the most common causes. With increased antibiotic resistance and vaccine evasion it is important to monitor the epidemiology of pathogens in circulation to inform clinical treatment and development, particularly in the setting of an influenza epidemic/pandemic.
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Affiliation(s)
- Denise E. Morris
- Infectious Disease Epidemiology Group, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, University Hospital Southampton Foundation NHS TrustSouthampton, United Kingdom
| | - David W. Cleary
- Infectious Disease Epidemiology Group, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, University Hospital Southampton Foundation NHS TrustSouthampton, United Kingdom
| | - Stuart C. Clarke
- Infectious Disease Epidemiology Group, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, University Hospital Southampton Foundation NHS TrustSouthampton, United Kingdom
- Global Health Research Institute, University of SouthamptonSouthampton, United Kingdom
- NIHR Southampton Respiratory Biomedical Research UnitSouthampton, United Kingdom
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Arduin H, Domenech de Cellès M, Guillemot D, Watier L, Opatowski L. An agent-based model simulation of influenza interactions at the host level: insight into the influenza-related burden of pneumococcal infections. BMC Infect Dis 2017; 17:382. [PMID: 28577533 PMCID: PMC5455134 DOI: 10.1186/s12879-017-2464-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 05/15/2017] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Host-level influenza virus-respiratory pathogen interactions are often reported. Although the exact biological mechanisms involved remain unelucidated, secondary bacterial infections are known to account for a large part of the influenza-associated burden, during seasonal and pandemic outbreaks. Those interactions probably impact the microorganisms' transmission dynamics and the influenza public health toll. Mathematical models have been widely used to examine influenza epidemics and the public health impact of control measures. However, most influenza models overlooked interaction phenomena and ignored other co-circulating pathogens. METHODS Herein, we describe a novel agent-based model (ABM) of influenza transmission during interaction with another respiratory pathogen. The interacting microorganism can persist in the population year round (endemic type, e.g. respiratory bacteria) or cause short-term annual outbreaks (epidemic type, e.g. winter respiratory viruses). The agent-based framework enables precise formalization of the pathogens' natural histories and complex within-host phenomena. As a case study, this ABM is applied to the well-known influenza virus-pneumococcus interaction, for which several biological mechanisms have been proposed. Different mechanistic hypotheses of interaction are simulated and the resulting virus-induced pneumococcal infection (PI) burden is assessed. RESULTS This ABM generates realistic data for both pathogens in terms of weekly incidences of PI cases, carriage rates, epidemic size and epidemic timing. Notably, distinct interaction hypotheses resulted in different transmission patterns and led to wide variations of the associated PI burden. Interaction strength was also of paramount importance: when influenza increased pneumococcus acquisition, 4-27% of the PI burden during the influenza season was attributable to influenza depending on the interaction strength. CONCLUSIONS This open-source ABM provides new opportunities to investigate influenza interactions from a theoretical point of view and could easily be extended to other pathogens. It provides a unique framework to generate in silico data for different scenarios and thereby test mechanistic hypotheses.
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Affiliation(s)
- Hélène Arduin
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases, UMR1181 - Université de Versailles Saint Quentin en Yvelines, Inserm, Institut Pasteur, B2PHI Unit – Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Matthieu Domenech de Cellès
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases, UMR1181 - Université de Versailles Saint Quentin en Yvelines, Inserm, Institut Pasteur, B2PHI Unit – Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Didier Guillemot
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases, UMR1181 - Université de Versailles Saint Quentin en Yvelines, Inserm, Institut Pasteur, B2PHI Unit – Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Laurence Watier
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases, UMR1181 - Université de Versailles Saint Quentin en Yvelines, Inserm, Institut Pasteur, B2PHI Unit – Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Lulla Opatowski
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases, UMR1181 - Université de Versailles Saint Quentin en Yvelines, Inserm, Institut Pasteur, B2PHI Unit – Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
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Verhagen LM, Hermsen M, Rivera-Olivero IA, Sisco MC, de Jonge MI, Hermans PWM, de Waard JH. Nasopharyngeal carriage of respiratory pathogens in Warao Amerindians: significant relationship with stunting. Trop Med Int Health 2017; 22:407-414. [PMID: 28072501 DOI: 10.1111/tmi.12835] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To assess risk factors for nasopharyngeal carriage of potential pathogens in geographically isolated Warao Amerindians in Venezuela. METHODS In this point prevalence survey, nasopharyngeal swabs were obtained from 1064 Warao Amerindians: 504 children aged 0-4 years, 227 children aged 5-10 years and 333 caregivers. Written questionnaires were completed to obtain information on demographics and environmental risk factors. Anthropometric measurements were performed in children aged 0-4 years. RESULTS Carriage rates of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and Moraxella catarrhalis were 51%, 7%, 1% and 13%, respectively. Crowding index, method of cooking and tobacco exposure were not associated with increased carriage. In multivariable analysis, an increase in height-for-age Z score (i.e. improved chronic nutritional status) was associated with decreased odds of S. pneumoniae colonisation (OR 0.76, 95% CI 0.70-0.83) in children aged 0-4 years. CONCLUSIONS Better knowledge of demographic and environmental risk factors facilitates better understanding of the dynamics of colonisation with respiratory bacteria in an Amerindian population. Poor chronic nutritional status was associated with increased pathogen carriage in children <5 years of age. The high rates of stunting generally observed in indigenous children may fuel the acquisition of respiratory bacteria that can lead to respiratory and invasive disease.
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Affiliation(s)
- Lilly M Verhagen
- Laboratorio de Tuberculosis, Universidad Central de Venezuela, Caracas, Venezuela
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
- Wilhelmina Children's Hospital Utrecht, Utrecht, The Netherlands
| | - Meyke Hermsen
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - María Carolina Sisco
- Laboratorio de Tuberculosis, Universidad Central de Venezuela, Caracas, Venezuela
| | - Marien I de Jonge
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Peter W M Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jacobus H de Waard
- Laboratorio de Tuberculosis, Universidad Central de Venezuela, Caracas, Venezuela
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Kobayashi M, Conklin LM, Bigogo G, Jagero G, Hampton L, Fleming-Dutra KE, Junghae M, Carvalho MDG, Pimenta F, Beall B, Taylor T, Laserson KF, Vulule J, Van Beneden C, Kim L, Feikin DR, Whitney CG, Breiman RF. Pneumococcal carriage and antibiotic susceptibility patterns from two cross-sectional colonization surveys among children aged <5 years prior to the introduction of 10-valent pneumococcal conjugate vaccine - Kenya, 2009-2010. BMC Infect Dis 2017; 17:25. [PMID: 28056828 PMCID: PMC5217209 DOI: 10.1186/s12879-016-2103-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 12/08/2016] [Indexed: 12/12/2022] Open
Abstract
Background Pneumococci are spread by persons with nasopharyngeal colonization, a necessary precursor to invasive disease. Pneumococcal conjugate vaccines can prevent colonization with vaccine serotype strains. In 2011, Kenya became one of the first African countries to introduce the 10-valent pneumococcal conjugate vaccine (PCV10) into its national immunization program. Serial cross-sectional colonization surveys were conducted to assess baseline pneumococcal colonization, antibiotic resistance patterns, and factors associated with resistance. Methods Annual surveys were conducted in one urban and one rural site during 2009 and 2010 among children aged <5 years. To reflect differences in vaccine target population, recruitment was age-stratified in Kibera, whereas a simple random sample of children was drawn in Lwak. Nasopharyngeal swabs were collected from eligible children. Pneumococci were isolated and serotyped. Antibiotic susceptibility testing was performed using the 2009 isolates. Antibiotic nonsusceptibility was defined as intermediate susceptibility or resistance to ≥1 antibiotics (i.e., penicillin, chloramphenicol, levofloxacin, erythromycin, tetracycline, cotrimoxazole, and clindamycin); multidrug resistance (MDR) was defined as nonsusceptibility to ≥3 antibiotics. Weighted analysis was conducted when appropriate. Modified Poisson regression was used to calculate factors associated with antibiotic nonsusceptibility. Results Of 1,087 enrolled (Kibera: 740, Lwak: 347), 90.0% of these were colonized with pneumococci, and 37.3% were colonized with PCV10 serotypes. There were no differences by survey site or year. Of 657 (of 730; 90%) isolates tested for antibiotic susceptibility, nonsusceptibility to cotrimoxazole and penicillin was found in 98.6 and 81.9% of isolates, respectively. MDR was found in 15.9% of isolates and most often involved nonsusceptibility to cotrimoxazole and penicillin; 40.4% of MDR isolates were PCV10 serotypes. In the multivariable model, PCV10 serotypes were independently associated with penicillin nonsusceptibility (Prevalence Ratio: 1.2, 95% CI 1.1–1.3), but not with MDR. Conclusions Before PCV10 introduction, nearly all Kenyan children aged <5 years were colonized with pneumococci, and PCV10 serotype colonization was common. PCV10 serotypes were associated with penicillin nonsusceptibility. Given that colonization with PCV10 serotypes is associated with greater risk for invasive disease than colonization with other serotypes, successful PCV10 introduction in Kenya is likely to have a substantial impact in reducing vaccine-type pneumococcal disease and drug-resistant pneumococcal infection. Electronic supplementary material The online version of this article (doi:10.1186/s12879-016-2103-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Miwako Kobayashi
- Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA, USA. .,Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA.
| | - Laura M Conklin
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Godfrey Bigogo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,International Emerging Infections Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Geofrey Jagero
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,International Emerging Infections Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Lee Hampton
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Katherine E Fleming-Dutra
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Muthoni Junghae
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,International Emerging Infections Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Maria da Gloria Carvalho
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Fabiana Pimenta
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Bernard Beall
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Thomas Taylor
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Kayla F Laserson
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - John Vulule
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Chris Van Beneden
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Lindsay Kim
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Daniel R Feikin
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,International Emerging Infections Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Cynthia G Whitney
- Division of Bacterial Diseases, Centers for Diseases Control and Prevention, 1600 Clifton Road NE, MS C-25, Atlanta, GA, 30329-4027, USA
| | - Robert F Breiman
- International Emerging Infections Program, Centers for Disease Control and Prevention, Nairobi, Kenya.,Emory Global Health Institute, Emory University, Atlanta, GA, USA
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Abstract
Streptococcus pneumoniae is an opportunistic pathogen globally associated with significant morbidity and mortality. It is capable of causing a wide range of diseases including sinusitis, conjunctivitis, otitis media, pneumonia, bacteraemia, sepsis, and meningitis. While its capsular polysaccharide is indispensible for invasive disease, and opsonising antibodies against the capsule are the basis for the current vaccines, a long history of biomedical research indicates that other components of this Gram-positive bacterium are also critical for virulence. Herein we review the contribution of pneumococcal virulence determinants to survival and persistence in the context of distinct anatomical sites. We discuss how these determinants allow the pneumococcus to evade mucociliary clearance during colonisation, establish lower respiratory tract infection, resist complement deposition and opsonophagocytosis in the bloodstream, and invade secondary tissues such as the central nervous system leading to meningitis. We do so in a manner that highlights both the critical role of the capsular polysaccharide and the accompanying and necessary protein determinants. Understanding the complex interplay between host and pathogen is necessary to find new ways to prevent pneumococcal infection. This review is an attempt to do so with consideration for the latest research findings.
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Streptococcus pneumoniae Colonization Disrupts the Microbial Community within the Upper Respiratory Tract of Aging Mice. Infect Immun 2016; 84:906-16. [PMID: 26787714 DOI: 10.1128/iai.01275-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/06/2016] [Indexed: 12/21/2022] Open
Abstract
Nasopharyngeal colonization by the Gram-positive bacterium Streptococcus pneumonia is a prerequisite for pneumonia and invasive pneumococcal diseases. Colonization is asymptomatic, involving dynamic and complex interplay between commensals, the host immune system, and environmental factors. The elderly are at an increased risk of developing pneumonia, which might be due to changes in the respiratory microbiota that would impact bacterial colonization and persistence within this niche. We hypothesized that the composition of the upper respiratory tract (URT) microbiota changes with age and subsequently can contribute to sustained colonization and inefficient clearance of S. pneumoniae To test this, we used a mouse model of pneumococcal colonization to compare the composition of the URT microbiota in young, middle-aged, and old mice in the naive state and during the course of colonization using nasal pharyngeal washes. Sequencing of variable region 3 (V3) of the 16S rRNA gene was used to identify changes occurring with age and throughout the course of S. pneumonia colonization. We discovered that age affects the composition of the URT microbiota and that colonization with S. pneumoniae is more disruptive of preexisting communities in older mice. We have further shown that host-pathogen interactions followingS. pneumonia colonization can impact the populations of resident microbes, including Staphylococcus and Haemophilus. Together, our findings indicate alterations to the URT microbiota could be detrimental to the elderly, resulting in increased colonization of S. pneumonia and decreased efficiency in its clearance.
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Hammitt LL, Crane RJ, Karani A, Mutuku A, Morpeth SC, Burbidge P, Goldblatt D, Kamau T, Sharif S, Mturi N, Scott JAG. Effect of Haemophilus influenzae type b vaccination without a booster dose on invasive H influenzae type b disease, nasopharyngeal carriage, and population immunity in Kilifi, Kenya: a 15-year regional surveillance study. LANCET GLOBAL HEALTH 2016; 4:e185-94. [PMID: 26853149 PMCID: PMC4763163 DOI: 10.1016/s2214-109x(15)00316-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 11/18/2015] [Accepted: 12/07/2015] [Indexed: 10/25/2022]
Abstract
BACKGROUND Haemophilus influenzae type b (Hib) conjugate vaccine, delivered as a three-dose series without a booster, was introduced into the childhood vaccination programme in Kenya in 2001. The duration of protection and need for a booster dose are unknown. We aimed to assess vaccine effectiveness, the impact of the vaccine on nasopharyngeal carriage, and population immunity after introduction of conjugate Hib vaccine in infancy without a booster dose in Kenya. METHODS This study took place in the Kilifi Health and Demographic Surveillance System (KHDSS), an area of Kenya that has been monitored for vital events and migration every 4 months since 2000. We analysed sterile site cultures for H influenzae type b from children (aged ≤12 years) admitted to the Kilifi County Hospital (KCH) from Jan 1, 2000, through to Dec 31, 2014. We determined the prevalence of nasopharyngeal carriage by undertaking cross-sectional surveys in random samples of KHDSS residents (of all ages) once every year from 2009 to 2012, and measured Hib antibody concentrations in five cross-sectional samples of children (aged ≤12 years) within the KHDSS (in 1998, 2000, 2004-05, 2007, and 2009). We calculated incidence rate ratios between the prevaccine era (2000-01) and the routine-use era (2004-14) and defined vaccine effectiveness as 1 minus the incidence rate ratio, expressed as a percentage. FINDINGS 40,482 children younger than 13 years resident in KHDSS were admitted to KCH between 2000 and 2014, 38,206 (94%) of whom had their blood cultured. The incidence of invasive H influenzae type b disease in children younger than 5 years declined from 62·6 (95% CI 46·0-83·3) per 100,000 in 2000-01 to 4·5 (2·5-7·5) per 100,000 in 2004-14, giving a vaccine effectiveness of 93% (95% CI 87-96). In the final 5 years of observation (2010-14), only one case of invasive H influenzae type b disease was detected in a child younger than 5 years. Nasopharyngeal H influenzae type b carriage was detected in one (0·2%) of 623 children younger than 5 years between 2009 and 2012. In the 2009 serosurvey, 92 (79%; 95% CI 70-86) of 117 children aged 4-35 months had long-term protective antibody concentrations. INTERPRETATION In this region of Kenya, use of a three-dose primary series of Hib vaccine without a booster dose has resulted in a significant and sustained reduction in invasive H influenzae type b disease. The prevalence of nasopharyngeal carriage is low and the profile of Hib antibodies suggests that protection wanes only after the age at greatest risk of disease. Although continued surveillance is important to determine whether effective control persists, these findings suggest that a booster dose is not currently required in Kenya. FUNDING Gavi, the Vaccine Alliance, Wellcome Trust, European Society for Paediatric Infectious Diseases, and National Institute for Health Research.
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Affiliation(s)
- Laura L Hammitt
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Rosie J Crane
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Angela Karani
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Alex Mutuku
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Susan C Morpeth
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Polly Burbidge
- Institute of Child Health, University College London, London, UK
| | - David Goldblatt
- Institute of Child Health, University College London, London, UK
| | - Tatu Kamau
- Kenya Ministry of Public Health and Sanitation, Kilifi, Kenya
| | - Shahnaaz Sharif
- Kenya Ministry of Public Health and Sanitation, Kilifi, Kenya
| | - Neema Mturi
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - J Anthony G Scott
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
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Associations Between Viral and Bacterial Potential Pathogens in the Nasopharynx of Children With and Without Respiratory Symptoms. Pediatr Infect Dis J 2015; 34:1296-301. [PMID: 26262821 DOI: 10.1097/inf.0000000000000872] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND Nasopharyngeal (NP) bacterial colonization is necessary for subsequent respiratory and/or invasive infection. Our study aimed at comparing NP bacterial colonization rates between children with and without symptoms of an acute viral respiratory tract infection and examining associations between identified microorganisms. METHODS Children 3 months to 6 years of age with and without an acute viral respiratory tract infection were recruited, and a questionnaire was filled. NP samples were examined for Streptococcus pneumoniae (SP), Haemophilus influenzae (HI), Moraxella catarrhalis (MC), Staphylococcus aureus and Streptococcus pyogenes by culture. Viruses were detected with polymerase chain reaction. RESULTS Median age of the 386 recruited children was 23.4 months, and 127 had no respiratory symptoms. More asymptomatic subjects were found negative for all bacteria tested (P < 0.01). SP (P < 0.01), MC (P = 0.001) and mixed bacterial colonization patterns were more frequent among symptomatic children (P < 0.05). Colonization of symptomatic, virus-positive children with MC was higher than in asymptomatic and/or virus-negative children (P = 0.005). The highest HI and MC colonization rates were recorded in association with influenza virus. A strongly negative association between SP and S. aureus, a higher rate of HI detection among SP colonized children and an increased likelihood of MC detection in the presence of HI were observed. HI colonization was more likely in the presence of respiratory syncytial virus and MC colonization was associated with rhinovirus detection. CONCLUSIONS Viruses are associated with different NP bacterial colonization patterns. Observed pathogens' associations may play a role in disease, and continuous surveillance is required to follow possible effects of interventions such as vaccines.
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Satzke C, Dunne EM, Porter BD, Klugman KP, Mulholland EK. The PneuCarriage Project: A Multi-Centre Comparative Study to Identify the Best Serotyping Methods for Examining Pneumococcal Carriage in Vaccine Evaluation Studies. PLoS Med 2015; 12:e1001903; discussion e1001903. [PMID: 26575033 PMCID: PMC4648509 DOI: 10.1371/journal.pmed.1001903] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 10/09/2015] [Indexed: 01/17/2023] Open
Abstract
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.
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Affiliation(s)
- Catherine Satzke
- Pneumococcal Research Group, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia
- * E-mail:
| | - Eileen M. Dunne
- Pneumococcal Research Group, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Barbara D. Porter
- Pneumococcal Research Group, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Keith P. Klugman
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - E. Kim Mulholland
- Pneumococcal Research Group, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Bojang A, Jafali J, Egere UE, Hill PC, Antonio M, Jeffries D, Greenwood BM, Roca A. Seasonality of Pneumococcal Nasopharyngeal Carriage in Rural Gambia Determined within the Context of a Cluster Randomized Pneumococcal Vaccine Trial. PLoS One 2015; 10:e0129649. [PMID: 26132206 PMCID: PMC4488590 DOI: 10.1371/journal.pone.0129649] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 05/08/2015] [Indexed: 11/18/2022] Open
Abstract
Background We conducted an ancillary study among individuals who had participated in a PCV-7 trial in rural Gambia, to determine the influence of season on the prevalence of pneumococcal carriage. Methods 636 individuals above 30 months of age were followed from 4 to 20 months after vaccination with PCV-7 or meningococcal-conjugate-vaccine. Nasopharyngeal swabs were collected periodically between November 2006 and June 2008. Overall, 4,495 NPS were collected. Results Prevalence of pneumococcal nasopharyngeal carriage in the study subjects (median age 11 years) was 55.0%; this prevalence decreased linearly with increasing age (p = 0.001). Prevalence of carriage was significantly higher during the dry than the rainy season for any pneumococcal carriage [57.6% versus 47.8% (p<0.001)], pneumococcal vaccine serotype carriage [10.3% versus 6.5% (p< 0.001)] and non-vaccine serotype carriage [49.7% versus 42.7% (p<0.001)]. Differences remained significant in the adjusted analysis. Conclusions In areas of Africa with marked variation in rainfall, seasonality of pneumococcal carriage needs to be considered when interpreting carriage data.
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Affiliation(s)
| | - James Jafali
- Medical Research Council Unit, Fajara, The Gambia
| | | | - Phillip C. Hill
- Medical Research Council Unit, Fajara, The Gambia
- Centre for International Health, School of Medicine, University of Otago, Dunedin, New Zealand
| | | | | | - Brian M. Greenwood
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Anna Roca
- Medical Research Council Unit, Fajara, The Gambia
- * E-mail:
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Abry MF, Kimenyi KM, Osowo FO, Odhiambo WO, Sewe SO, Kulohoma BW. Genetic diversity of the Pneumococcal CbpA: Implications for next-generation vaccine development. Hum Vaccin Immunother 2015; 11:1261-7. [PMID: 25902300 DOI: 10.1080/21645515.2015.1021521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Pneumococci are capable of vaccine escape by genetic recombination at the targeted capsular locus, significantly reducing long-term vaccine effectiveness. Recently, efforts have been redirected to understanding pneumococcal biology related to potential next-generation vaccine candidates. A variety of serotype-independent protein antigens capable of inducing protective immune responses in tissue culture and animal models of infection have been identified. However, ideal vaccine candidates that are conserved across all genotypes, provide broad population coverage, and induce T-cell dependent immune responses are still under investigation. We examined whether immune responses due to the highly polymorphic CbpA antigen are due to a conserved domain capable of evoking specific immune "memory" across all genotypes of pneumococci. We defined the genotypes in a global dataset of 213 pneumococcal isolates. This isolate collection was genotypically diverse and ideal for establishing the presence of conserved CbpA epitopes as potential protein vaccine candidates. Examination of the CbpA locus sequence was highly polymorphic at both the nucleic acid and amino acid level. Despite this high polymorphism some domains are broadly conserved and consist of different amino acid residues with the same physicochemical properties, and therefore have similar tertiary structures. The two most common domains identified in the CbpA gene are modular teichoic acid phosphorylcholine esterase Pce (2bib:A), and R2 domain (1w9r:A). These conserved domains are immunogenic, therefore capable of inducing long-term host immune responses; moreover they are extracellularly located and thus accessible. We proposed their evaluation as suitable next-generation CbpA-fusion protein vaccine candidates.
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Affiliation(s)
- Muna F Abry
- a Centre for Biotechnology and Bioinformatics; University of Nairobi ; Nairobi , Kenya
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Usonis V, Stacevičienė I, Petraitienė S, Vaičiūnienė D, Alasevičius T, Kirslienė J. Streptococcus pneumoniae nasopharyngeal colonisation in children aged under six years with acute respiratory tract infection in Lithuania, February 2012 to March 2013. ACTA ACUST UNITED AC 2015; 20:34-41. [PMID: 25860394 DOI: 10.2807/1560-7917.es2015.20.13.21079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
serotypes among children in Lithuania are limited. A prospective study was carried out from February 2012 to March 2013 to evaluate the circulation of SPn serotypes among young children in five cities of Lithuania before the introduction of universal vaccination with pneumococcal conjugate vaccine (PCV). A total of 900 children under six years of age who presented to primary care centres or a hospital emergency department with acute respiratory tract infection (RTI) were enrolled in the study. The SPn colonisation rate was40.8% (367/900), with a peak at two and three years old(48.8% and 45.4%, respectively). Of the 367 SPn isolates, the most common serotypes were 6B (15.8%,n = 58), 19F (13.9%, n = 51), 23F (13.9%, n = 51), 15(10.1%, n = 37), 14 (9.5%, n = 35), 6A (9.3%, n= 34),11 (4.6%, n = 17), 3 (3.0%, n = 11) and 18C (3.0%, n =11); less frequent were 23 (non-23F) (2.7%, n = 10), 19A(2.2%, n = 8) and 9V (1.6%, n = 6). Serotypes 6A and 11 were more common in children under two years-old;18C was found only in children aged two to five years.The serotypes found might be an important predictor of the likely effectiveness of the PCVs currently available in Lithuania
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Affiliation(s)
- V Usonis
- Vilnius University, Clinic of Children's Diseases, Vilnius, Lithuania
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Mills RO, Twum-Danso K, Owusu-Agyei S, Donkor ES. Epidemiology of pneumococcal carriage in children under five years of age in Accra, Ghana. Infect Dis (Lond) 2015; 47:326-31. [PMID: 25761718 DOI: 10.3109/00365548.2014.994185] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Although the majority of pneumococcal infections occur in the developing world, pneumococcal epidemiology is poorly understood in these settings. The aim of the study was to investigate the epidemiology of pneumococcal carriage among children younger than 5 years at a paediatric healthcare centre in Ghana. METHOD Four-hundred and twenty-three children were randomly sampled and nasopharyngeal specimens were collected from them. The specimens were cultured for Streptococcus pneumoniae, and the isolates were subjected to antibiotic susceptibility testing and serotyping by latex agglutination. Epidemiological data on demographic and clinical features of the study subjects were collected. RESULTS The prevalence of pneumococcal carriage was 48.9% (207/422), with age groups 43-48 months having the highest carriage prevalence. In the multivariate analysis, pneumococcal carriage was significantly associated with runny nose (odds ratio = 1.9, p = 0.003) and day-care attendance (odds ratio = 1.5, p = 0.04). No pneumococcal resistance was observed for ceftriaxone, while the prevalence of resistance to the other antibiotics tested was: cotrimoxazole 100%, ampicillin 88%, tetracycline 78%, penicillin 63% and erythromycin 24%. Fourteen different pneumococcal serogroups/serotypes were identified and serogroup 6 was the most prevalent (30%), followed by serotype 19 (20%). CONCLUSIONS We conclude that pneumococcal carriage among the study children is high and the carried strains have a high level of resistance (> 50%) to several antibiotics. Ceftriaxone is a suitable antibiotic for treating pneumococcal infections in Ghana, and the use of this antibiotic coupled with the pneumococcal vaccination is expected to significantly reduce the burden of pneumococcal disease in the country.
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Affiliation(s)
- Richael Odarkor Mills
- From the 1 Department of Microbiology, University of Ghana Medical School , Accra , Ghana
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Jomrich N, Kellner S, Djukic M, Eiffert H, Nau R. Absence of Streptococcus pneumoniae in pharyngeal swabs of geriatric inpatients. Infect Dis (Lond) 2015; 47:504-9. [PMID: 25746605 DOI: 10.3109/00365548.2015.1007476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Colonization of the pharynx by Streptococcus pneumoniae was studied in 185 in-hospital geriatric patients (median age 81 years) from 29 March 2011 to 22 June 2011. Swabs were plated on blood agar plates. Colonies with a morphology suggesting S. pneumoniae were further analyzed. Surprisingly, pneumococci were not found in any of the samples. Pneumococci chronically colonizing the pharynx of elderly people may be much rarer than previously thought and probably are not the source of pneumococcal pneumonia in old age.
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Affiliation(s)
- Nina Jomrich
- From the 1 Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende , Göttingen , Germany
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Chen HX, Lai CH, Hsu HY, Huang JC, Wu HS, Ho MW, Tsai MH, Lin CD. The bacterial interactions in the nasopharynx of children receiving adenoidectomy. Biomedicine (Taipei) 2015; 5:6. [PMID: 25705586 PMCID: PMC4326659 DOI: 10.7603/s40681-015-0006-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 01/19/2015] [Indexed: 11/21/2022] Open
Abstract
Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae are the common pathogens that colonize in the nasopharynx of children. Polymicrobial interactions are thought to play an important role in different sites throughout the human body. However, there are currently very few studies that investigate the interactions between S. aureus, S. pneumoniae, and H. influenzae in the nasopharynx. We retrospectively analyzed the adenoid tissue culture from 269 children who received adenoidectomy. S. aureus, S. pneumoniae, and H. influenzae constituted the major microorganisms which were cultured from these adenoidectomies, at 23.4%, 21.6%, and 18.2%, respectively. S. pneumoniae and H. influenzae were the most prevalent in the preschool-aged children (3 < age ≤ 6), whereas S. aureus was more prevalent in infants and toddlers (age ≤ 3) and school-aged children (age > 6). Bacterial interference was found between S. aureus and S. pneumoniae and between S. aureus and H. influenzae, whereas there was an association found between S. pneumoniae and H. influenzae. The synergism and antagonism among these three species are investigated in the following paper, with the possible mechanisms involved in these interactions also discussed.
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Affiliation(s)
- Hao-Xiang Chen
- School of Medicine and Graduate Institute of Basic Medical Science, China Medical University, 404 Taichung, Taiwan
| | - Chih-Ho Lai
- School of Medicine and Graduate Institute of Basic Medical Science, China Medical University, 404 Taichung, Taiwan ; Department of Nursing, Asia University, 413 Taichung, Taiwan
| | - Hui-Ying Hsu
- School of Medicine and Graduate Institute of Basic Medical Science, China Medical University, 404 Taichung, Taiwan
| | - Ju-Chun Huang
- School of Medicine and Graduate Institute of Basic Medical Science, China Medical University, 404 Taichung, Taiwan ; Department of Laboratory Medicine, China Medical University Hospital, 404 Taichung, Taiwan
| | - Hua-Shan Wu
- Department of Nursing, Asia University, 413 Taichung, Taiwan
| | - Mao-Wang Ho
- Department of Internal Medicine, China Medical University Hospital, 404 Taichung, Taiwan
| | - Ming-Hsui Tsai
- Graduate Institute of Clinical Medical Science, China Medical University, 404 Taichung, Taiwan ; Department of Otolaryngology-Head and Neck Surgery, China Medical University Hospital, No. 2, Yuh-Der Road, 404 Taichung, Taiwan
| | - Chia-Der Lin
- School of Medicine and Graduate Institute of Basic Medical Science, China Medical University, 404 Taichung, Taiwan ; Graduate Institute of Clinical Medical Science, China Medical University, 404 Taichung, Taiwan ; Department of Otolaryngology-Head and Neck Surgery, China Medical University Hospital, No. 2, Yuh-Der Road, 404 Taichung, Taiwan
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Rutebemberwa E, Mpeka B, Pariyo G, Peterson S, Mworozi E, Bwanga F, Källander K. High prevalence of antibiotic resistance in nasopharyngeal bacterial isolates from healthy children in rural Uganda: A cross-sectional study. Ups J Med Sci 2015; 120:249-56. [PMID: 26305429 PMCID: PMC4816885 DOI: 10.3109/03009734.2015.1072606] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In Uganda, the main causes of death in children under 5 years of age are malaria and pneumonia--often due to delayed diagnosis and treatment. In preparation for a community case management intervention for pneumonia and malaria, the bacterial composition of the nasopharyngeal flora and its in vitro resistance were determined in children aged five or under to establish baseline resistance to commonly used antibiotics. METHODS In a population-based survey in April 2008, nasopharyngeal specimens were collected from 152 randomly selected healthy children under 5 years of age in the Iganga/Mayuge Health and Demographic Surveillance Site (HDSS). Medical history and prior treatment were recorded. Demographic characteristics and risk factors for carriage of resistant strains were obtained from the HDSS census. Bacteria were isolated and analysed for antibiotic susceptibility using disk diffusion and E test. RESULTS Streptococcus pneumoniae (S. pneumoniae) carriage was 58.6%, and, while most (80.9%) isolates had intermediate resistance to penicillin, none was highly resistant. Whereas no isolate was resistant to erythromycin, 98.9% were resistant to trimethoprim-sulphamethoxazole (co-trimoxazole). CONCLUSIONS In vitro resistance in S. pneumoniae to co-trimoxazole treatment was high, and the majority of isolates had intermediate resistance to penicillin. To inform treatment policies on the clinical efficacy of current treatment protocols for pneumonia in health facilities and at the community level, routine surveillance of resistance in pneumonia pathogens is needed as well as research on treatment efficacy in cases with resistant strains. Improved clinical algorithms and diagnostics for pneumonia should be developed.
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Affiliation(s)
| | | | - George Pariyo
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | | | - Edison Mworozi
- Department of Paediatrics and Child Health, Makerere University Medical School, Kampala, Uganda
| | - Freddie Bwanga
- Department of Microbiology, Makerere University Faculty of Medicine, Kampala, Uganda, and
| | - Karin Källander
- Correspondence: Karin Källander, Division of Global Health, Tomteboda vägen 18A, Karolinska Institutet, SE-171 77 Stockholm, Sweden. E-mail:
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Abstract
Community-acquired pneumonia is one of the most common reasons for emergency department (ED) visits in children and adults. Despite its prevalence, there are many challenges to proper diagnosis and management of pneumonia. There is no accurate and timely etiologic gold standard to differentiate bacterial from viral disease, and there are limitations with precise risk stratification of patients to ensure appropriate site-of-care decisions. Clinical factors obtained by history and physical examination have limited the ability to diagnose pneumonia etiology and severity. Biomarkers offer information about the host response to infection and pathogen activity within the host that can serve to augment clinical features in decision-making. As science and technology progress, novel biomarkers offer great potential in aiding critical decisions for patients with pneumonia. This review summarizes existing knowledge about biomarkers of host response and pathogen activity, in addition to briefly reviewing emerging biomarkers using novel technologies.
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Nzenze SA, Shiri T, Nunes MC, Klugman KP, Kahn K, Twine R, de Gouveia L, von Gottberg A, Madhi SA. Temporal association of infant immunisation with pneumococcal conjugate vaccine on the ecology of Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus nasopharyngeal colonisation in a rural South African community. Vaccine 2014; 32:5520-30. [PMID: 25101982 DOI: 10.1016/j.vaccine.2014.06.091] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Immunisation of children with pneumococcal conjugate vaccines (PCV) may affect the bacterial-ecology of the nasopharynx, including colonisation by Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. The aim of this study was to evaluate the effect of infant PCV-immunisation on the nasopharyngeal ecology of these potentially pathogenic bacteria in a rural African setting. METHODS Two cross sectional surveys were undertaken from May to October in 2009 (Period-1) which coincided with the introduction of 7-valent PCV (PCV7) and in May-October 2011 (Period-2). Consenting household members, where there was a child <2 years of age in residence, had nasopharyngeal swabs undertaken for culture. RESULTS From Period-1 to Period-2 in children 0-2 years and 3-12 years, prevalence of overall S. pneumoniae colonisation decreased from 74.9% to 67.0% (p<0.001) and H. influenzae declined among children 3-12 years (55.1-45.3%, p<0.001) but not among those <2 years. The prevalence of S. aureus remained unchanged in all children. Competitive associations were found between S. pneumoniae and S. aureus and between H. influenzae and S. aureus among children. In individuals >12 years, the prevalence of colonisation decreased from 11.2% to 6.8%, 16.7% to 8.8% and 31.2% to 23.7% for S. pneumoniae, H. influenzae and S. aureus, respectively; p<0.001 for all comparions. Synergistic relationships for S. aureus with H. influenzae and S. pneumoniae were observed in both periods among this group.
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Affiliation(s)
- S A Nzenze
- Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - T Shiri
- Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - M C Nunes
- Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - K P Klugman
- Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Global Health, Rollins School of Public Health, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA, USA
| | - K Kahn
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Centre for Global Health Research, Umeå University, Umeå, Sweden; INDEPTH Network, Accra, Ghana
| | - R Twine
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - L de Gouveia
- Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; National Institute for Communicable Diseases (NICD): A Division of the National Health Laboratory Service (NHLS), Sandringham, South Africa
| | - A von Gottberg
- Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; National Institute for Communicable Diseases (NICD): A Division of the National Health Laboratory Service (NHLS), Sandringham, South Africa
| | - S A Madhi
- Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; National Institute for Communicable Diseases (NICD): A Division of the National Health Laboratory Service (NHLS), Sandringham, South Africa.
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Adegbola RA, DeAntonio R, Hill PC, Roca A, Usuf E, Hoet B, Greenwood BM. Carriage of Streptococcus pneumoniae and other respiratory bacterial pathogens in low and lower-middle income countries: a systematic review and meta-analysis. PLoS One 2014; 9:e103293. [PMID: 25084351 PMCID: PMC4118866 DOI: 10.1371/journal.pone.0103293] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 06/27/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Infection with Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide, especially in low income countries where pneumococcal conjugate vaccines (PCVs) are still underused. In countries where PCVs have been introduced, much of their efficacy has resulted from their impact on nasopharyngeal carriage in vaccinated children. Understanding the epidemiology of carriage for S. pneumoniae and other common respiratory bacteria in developing countries is crucial for implementing appropriate vaccination strategies and evaluating their impact. METHODS AND FINDINGS We have systematically reviewed published studies reporting nasopharyngeal or oropharyngeal carriage of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and Neisseria meningitidis in children and adults in low and lower-middle income countries. Studies reporting pneumococcal carriage for healthy children <5 years of age were selected for a meta-analysis. The prevalences of carriage for S. pneumoniae, H. influenzae, and M. catarrhalis were generally higher in low income than in lower-middle income countries and were higher in young children than in adults. The prevalence of S. aureus was high in neonates. Meta-analysis of data from young children before the introduction of PCVs showed a pooled prevalence estimate of 64.8% (95% confidence interval, 49.8%-76.1%) in low income countries and 47.8% (95% confidence interval, 44.7%-50.8%) in lower-middle income countries. The most frequent serotypes were 6A, 6B, 19A, 19F, and 23F. CONCLUSIONS In low and lower-middle income countries, pneumococcal carriage is frequent, especially in children, and the spectrum of serotypes is wide. However, because data are limited, additional studies are needed to adequately assess the impact of PCV introduction on carriage of respiratory bacteria in these countries.
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Affiliation(s)
| | | | - Philip C. Hill
- Medical Research Council Unit, Banjul, The Gambia
- Centre for International Health, School of Medicine, University of Otago, Dunedin, New Zealand
| | - Anna Roca
- Medical Research Council Unit, Banjul, The Gambia
| | - Effua Usuf
- Medical Research Council Unit, Banjul, The Gambia
| | | | - Brian M. Greenwood
- Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Impact of experimental human pneumococcal carriage on nasopharyngeal bacterial densities in healthy adults. PLoS One 2014; 9:e98829. [PMID: 24915552 PMCID: PMC4051691 DOI: 10.1371/journal.pone.0098829] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/06/2014] [Indexed: 12/05/2022] Open
Abstract
Colonization of the nasopharynx by Streptococcus pneumoniae is a necessary precursor to pneumococcal diseases that result in morbidity and mortality worldwide. The nasopharynx is also host to other bacterial species, including the common pathogens Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis. To better understand how these bacteria change in relation to pneumococcal colonization, we used species-specific quantitative PCR to examine bacterial densities in 52 subjects 7 days before, and 2, 7, and 14 days after controlled inoculation of healthy human adults with S. pneumoniae serotype 6B. Overall, 33 (63%) of subjects carried S. pneumoniae post-inoculation. The baseline presence and density of S. aureus, H. influenzae, and M. catarrhalis were not statistically associated with likelihood of successful pneumococcal colonization at this study’s sample size, although a lower rate of pneumococcal colonization in the presence of S. aureus (7/14) was seen compared to that in the presence of H. influenzae (12/16). Among subjects colonized with pneumococci, the number also carrying either H. influenzae or S. aureus fell during the study and at 14 days post-inoculation, the proportion carrying S. aureus was significantly lower among those who were colonized with S. pneumoniae (p = 0.008) compared to non-colonized subjects. These data on bacterial associations are the first to be reported surrounding experimental human pneumococcal colonization and show that co-colonizing effects are likely subtle rather than absolute.
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Cantais A, Mory O, Pillet S, Verhoeven PO, Bonneau J, Patural H, Pozzetto B. Epidemiology and microbiological investigations of community-acquired pneumonia in children admitted at the emergency department of a university hospital. J Clin Virol 2014; 60:402-7. [PMID: 24915939 PMCID: PMC7106426 DOI: 10.1016/j.jcv.2014.05.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 05/02/2014] [Accepted: 05/12/2014] [Indexed: 01/15/2023]
Abstract
Systematic antimicrobials are recommended in community-acquired pneumonia of child. A large panel of bacteria and viruses was detected in 85 children exhibiting CAP. More than 60% of children with CAP exhibited an exclusive viral infection. A co-infection with at least 2 viruses was observed in >40% of the children. Data suggest that the use of antimicrobials in child's CAP should be revisited.
Background The management of children with community-acquired pneumonia (CAP) is largely influenced by the development of new molecular diagnostic tests that allow the simultaneous detection of a wide range of pathogens. Objectives Evaluation of a diagnostic approach including multiplex PCR assays for revisiting the epidemiology and etiology of CAP in children at hospital. Study design Children of all ages consulting at the Emergency Department of the University hospital of Saint-Etienne, France, during the 2012–2013 winter period were included. In addition to bacterial cultures, the following pathogens were detected using biplex commercially-available rt-PCR tests: adenovirus, respiratory syncytial virus, human metapneumovirus, bocavirus, rhinovirus/enterovirus, coronavirus, influenza viruses A and B, parainfluenza viruses, Mycoplasma pneumoniae and Chlamydophila pneumonia. Results From 85 patients with CAP, at least one pathogen was identified in 81 cases (95.3%), including 4 bacterial exclusive infections (4.7%), 53 viral exclusive infections (62.4%) and 24 mixed infections (28.2%). Coinfection by at least two viruses was observed in 37 cases (43.5%). Mean age was higher in the case of documented bacterial infection (P < 0.05). In the subgroup of viral exclusive infection, the mean age of severe cases was 2.0 years vs 3.8 years in mild and moderate cases (P < 0.05). Conclusions These findings highlight the huge proportion of CAP of viral origin, the high number of co-infection by multiple viruses and the low number of bacterial CAP, notably in children under 5 years, and address the need to re-evaluate the indications of empiric antimicrobial treatment in this age group.
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Affiliation(s)
- Aymeric Cantais
- Department of Pediatric Emergency, University-Hospital of Saint-Etienne, CHU de Saint-Etienne, 42055 Saint-Etienne Cedex 02, France
| | - Olivier Mory
- Department of Pediatric Emergency, University-Hospital of Saint-Etienne, CHU de Saint-Etienne, 42055 Saint-Etienne Cedex 02, France
| | - Sylvie Pillet
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA3064, Faculty of Medicine of Saint-Etienne, University of Lyon, 42023 Saint-Etienne Cedex 02, France
| | - Paul O Verhoeven
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA3064, Faculty of Medicine of Saint-Etienne, University of Lyon, 42023 Saint-Etienne Cedex 02, France
| | - Julie Bonneau
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA3064, Faculty of Medicine of Saint-Etienne, University of Lyon, 42023 Saint-Etienne Cedex 02, France
| | - Hugues Patural
- Pediatric Intensive Care Unit, University-Hospital of Saint-Etienne, CHU de Saint Etienne, 42055 Saint-Etienne Cedex 02, France
| | - Bruno Pozzetto
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA3064, Faculty of Medicine of Saint-Etienne, University of Lyon, 42023 Saint-Etienne Cedex 02, France.
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Almeida ST, Nunes S, Santos Paulo AC, Valadares I, Martins S, Breia F, Brito-Avô A, Morais A, de Lencastre H, Sá-Leão R. Low prevalence of pneumococcal carriage and high serotype and genotype diversity among adults over 60 years of age living in Portugal. PLoS One 2014; 9:e90974. [PMID: 24604030 PMCID: PMC3946249 DOI: 10.1371/journal.pone.0090974] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/06/2014] [Indexed: 11/27/2022] Open
Abstract
Pneumococcal disease is frequent at the extremes of age. While several studies have looked at colonization among young children, much less is known among the elderly. We aimed to evaluate pneumococcal carriage among elderly adults living in Portugal. Between April 2010 and December 2012, nasopharyngeal and oropharyngeal swabs of adults over 60 years of age, living in an urban area (n = 1,945) or in a rural area (n = 1,416), were obtained. Pneumococci were isolated by culture-based standard procedures, identified by optochin susceptibility, bile solubility and PCR screening for lytA and cpsA, and characterized by antibiotype, serotype, and MLST. Associations between pneumococcal carriage, socio-demographic and clinical characteristics were evaluated by univariate analysis and multiple logistic regression. The global prevalence of carriage was 2.3% (95% CI: 1.8-2.8). In the multiple logistic regression analysis, smoking, being at a retirement home, and living in a rural area increased the odds of being a pneumococcal carrier by 4.4-fold (95% CI: 1.9-9.2), 2.0-fold (95% CI: 1.1-3.6) and 2.0-fold (95% CI: 1.2-3.5), respectively. Among the 77 pneumococcal isolates, 26 serotypes and 40 STs were identified. The most prevalent serotypes were (in decreasing order) 19A, 6C, 22F, 23A, 35F, 11A, and 23B, which accounted, in total, for 60.0% of the isolates. Most isolates (93.5%) had STs previously described in the MLST database. Resistance to macrolides, non-susceptibility to penicillin and multidrug resistance were found in 19.5%, 11.7%, and 15.6% of the isolates, respectively. We conclude that the prevalence of pneumococcal carriage in the elderly, in Portugal, as determined by culture-based methods, is low. Serotype and genotype diversity is high. Living in a rural area, in a retirement home, and being a smoker increased the risk of pneumococcal carriage. This study contributes to the establishment of a baseline that may be used to monitor how novel pneumococcal vaccines impact on colonization among the elderly.
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Affiliation(s)
- Sónia T. Almeida
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sónia Nunes
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana Cristina Santos Paulo
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Idalina Valadares
- Agrupamento de Centros de Saúde Oeiras - Carnaxide, Oeiras, Portugal
| | - Sara Martins
- Agrupamento de Centros de Saúde Oeiras - Carnaxide, Oeiras, Portugal
| | - Fátima Breia
- Agrupamento de Centros de Saúde Alentejo Central II, Évora, Portugal
| | - António Brito-Avô
- Agrupamento de Centros de Saúde Oeiras - Carnaxide, Oeiras, Portugal
| | - Ana Morais
- Agrupamento de Centros de Saúde Oeiras - Carnaxide, Oeiras, Portugal
| | - Hermínia de Lencastre
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Microbiology of Infectious Diseases, The Rockefeller University, New York, New York, United States of America
| | - Raquel Sá-Leão
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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Pawlowski B, Nowak J, Borkowska BARBARA, Drulis-Kawa Z. Human body morphology, prevalence of nasopharyngeal potential bacterial pathogens, and immunocompetence handicap principal. Am J Hum Biol 2014; 26:305-10. [DOI: 10.1002/ajhb.22510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/29/2013] [Accepted: 01/08/2014] [Indexed: 11/09/2022] Open
Affiliation(s)
- Boguslaw Pawlowski
- Department of Human Biology; University of Wroclaw; Kuznicza 35 50-138 Wroclaw Poland
| | - Judyta Nowak
- Department of Human Biology; University of Wroclaw; Kuznicza 35 50-138 Wroclaw Poland
| | - BARBARA Borkowska
- Department of Human Biology; University of Wroclaw; Kuznicza 35 50-138 Wroclaw Poland
| | - Zuzanna Drulis-Kawa
- Department of Pathogen Biology and Immunology; University of Wroclaw; Przybyszewskiego 63/77 51-148 Wroclaw Poland
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Le Polain de Waroux O, Flasche S, Prieto-Merino D, Edmunds WJ. Age-dependent prevalence of nasopharyngeal carriage of streptococcus pneumoniae before conjugate vaccine introduction: a prediction model based on a meta-analysis. PLoS One 2014; 9:e86136. [PMID: 24465920 PMCID: PMC3900487 DOI: 10.1371/journal.pone.0086136] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/04/2013] [Indexed: 11/18/2022] Open
Abstract
Introduction Data on the prevalence of nasopharyngeal carriage of S.pneumoniae in all age groups are important to help predict the impact of introducing pneumococcal conjugate vaccines (PCV) into routine infant immunization, given the important indirect effect of the vaccine. Yet most carriage studies are limited to children under five years of age. We here explore the association between carriage prevalence and serotype distribution in children aged ≥5 years and in adults compared to children. Methods We conducted a systematic review of studies providing carriage estimates across age groups in healthy populations not previously exposed to PCV, using MEDLINE and Embase. We used Bayesian linear meta-regression models to predict the overall carriage prevalence as well as the prevalence and distribution of vaccine and nonvaccine type (VT and NVT) serotypes in older age groups as a function of that in <5 y olds. Results Twenty-nine studies compromising of 20,391 individuals were included in the analysis. In all studies nasopharyngeal carriage decreased with increasing age. We found a strong positive linear association between the carriage prevalence in pre-school childen (<5 y) and both that in school aged children (5–17 y olds) and in adults. The proportion of VT serotypes isolated from carriers was consistently lower in older age groups and on average about 73% that of children <5 y among 5–17 y olds and adults respectively. We provide a prediction model to infer the carriage prevalence and serotype distribution in 5–17 y olds and adults as a function of that in children <5 years of age. Conclusion Such predictions are helpful for assessing the potential population-wide effects of vaccination programmes, e.g. via transmission models, and thus assist in the design of future pneumococcal conjugate vaccination strategies.
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Affiliation(s)
- Olivier Le Polain de Waroux
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Stefan Flasche
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David Prieto-Merino
- Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - W. John Edmunds
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Usuf E, Bottomley C, Adegbola RA, Hall A. Pneumococcal carriage in sub-Saharan Africa--a systematic review. PLoS One 2014; 9:e85001. [PMID: 24465464 PMCID: PMC3896352 DOI: 10.1371/journal.pone.0085001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 11/28/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Pneumococcal epidemiology varies geographically and few data are available from the African continent. We assess pneumococcal carriage from studies conducted in sub-Saharan Africa (sSA) before and after the pneumococcal conjugate vaccine (PCV) era. METHODS A search for pneumococcal carriage studies published before 2012 was conducted to describe carriage in sSA. The review also describes pneumococcal serotypes and assesses the impact of vaccination on carriage in this region. RESULTS Fifty-seven studies were included in this review with the majority (40.3%) from South Africa. There was considerable variability in the prevalence of carriage between studies (I-squared statistic = 99%). Carriage was higher in children and decreased with increasing age, 63.2% (95% CI: 55.6-70.8) in children less than 5 years, 42.6% (95% CI: 29.9-55.4) in children 5-15 years and 28.0% (95% CI: 19.0-37.0) in adults older than 15 years. There was no difference in the prevalence of carriage between males and females in 9/11 studies. Serotypes 19F, 6B, 6A, 14 and 23F were the five most common isolates. A meta-analysis of four randomized trials of PCV vaccination in children aged 9-24 months showed that carriage of vaccine type (VT) serotypes decreased with PCV vaccination; however, overall carriage remained the same because of a concomitant increase in non-vaccine type (NVT) serotypes. CONCLUSION Pneumococcal carriage is generally high in the African continent, particularly in young children. The five most common serotypes in sSA are among the top seven serotypes that cause invasive pneumococcal disease in children globally. These serotypes are covered by the two PCVs recommended for routine childhood immunization by the WHO. The distribution of serotypes found in the nasopharynx is altered by PCV vaccination.
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Affiliation(s)
- Effua Usuf
- Child Survival, Medical Research Council The Gambia Unit, Fajara, The Gambia
| | - Christian Bottomley
- Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Andrew Hall
- Faculty of Epidemiology and Public Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Population genetic structure of Streptococcus pneumoniae in Kilifi, Kenya, prior to the introduction of pneumococcal conjugate vaccine. PLoS One 2013; 8:e81539. [PMID: 24282605 PMCID: PMC3839905 DOI: 10.1371/journal.pone.0081539] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022] Open
Abstract
Background The 10-valent pneumococcal conjugate vaccine (PCV10) was introduced in Kenya in 2011. Introduction of any PCV will perturb the existing pneumococcal population structure, thus the aim was to genotype pneumococci collected in Kilifi before PCV10. Methods and Findings Using multilocus sequence typing (MLST), we genotyped >1100 invasive and carriage pneumococci from children, the largest collection genotyped from a single resource-poor country and reported to date. Serotype 1 was the most common serotype causing invasive disease and was rarely detected in carriage; all serotype 1 isolates were members of clonal complex (CC) 217. There were temporal fluctuations in the major circulating sequence types (STs); and although 1-3 major serotype 1, 14 or 23F STs co-circulated annually, the two major serotype 5 STs mainly circulated independently. Major STs/CCs also included isolates of serotypes 3, 12F, 18C and 19A and each shared ≤2 MLST alleles with STs that circulate widely elsewhere. Major CCs associated with non-PCV10 serotypes were predominantly represented by carriage isolates, although serotype 19A and 12F CCs were largely invasive and a serotype 10A CC was equally represented by invasive and carriage isolates. Conclusions Understanding the pre-PCV10 population genetic structure in Kilifi will allow for the detection of changes in prevalence of the circulating genotypes and evidence for capsular switching post-vaccine implementation.
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Weinberger DM, Grant LR, Steiner CA, Weatherholtz R, Santosham M, Viboud C, O'Brien KL. Seasonal drivers of pneumococcal disease incidence: impact of bacterial carriage and viral activity. Clin Infect Dis 2013; 58:188-94. [PMID: 24190895 DOI: 10.1093/cid/cit721] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Winter-seasonal epidemics of pneumococcal disease provide an opportunity to understand the drivers of incidence. We sought to determine whether seasonality of invasive pneumococcal disease is caused by increased nasopharyngeal transmission of the bacteria or increased susceptibility to invasive infections driven by cocirculating winter respiratory viruses. METHODS We analyzed pneumococcal carriage and invasive disease data collected from children <7 years old in the Navajo/White Mountain Apache populations between 1996 and 2012. Regression models were used to quantify seasonal variations in carriage prevalence, carriage density, and disease incidence. We also fit a multivariate model to determine the contribution of carriage prevalence and RSV activity to pneumococcal disease incidence while controlling for shared seasonal factors. RESULTS The seasonal patterns of invasive pneumococcal disease epidemics varied significantly by clinical presentation: bacteremic pneumococcal pneumonia incidence peaked in late winter, whereas invasive nonpneumonia pneumococcal incidence peaked in autumn. Pneumococcal carriage prevalence and density also varied seasonally, with peak prevalence occurring in late autumn. In a multivariate model, RSV activity was associated with significant increases in bacteremic pneumonia cases (attributable percentage, 15.5%; 95% confidence interval [CI], 1.8%-26.1%) but was not associated with invasive nonpneumonia infections (8.0%; 95% CI, -4.8% to 19.3%). In contrast, seasonal variations in carriage prevalence were associated with significant increases in invasive nonpneumonia infections (31.4%; 95% CI, 8.8%-51.4%) but not with bacteremic pneumonia. CONCLUSIONS The seasonality of invasive pneumococcal pneumonia could be due to increased susceptibility to invasive infection triggered by viral pathogens, whereas seasonality of other invasive pneumococcal infections might be primarily driven by increased nasopharyngeal transmission of the bacteria.
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Affiliation(s)
- Daniel M Weinberger
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
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Dayie NTKD, Arhin RE, Newman MJ, Dalsgaard A, Bisgaard M, Frimodt-Møller N, Slotved HC. Penicillin resistance and serotype distribution of Streptococcus pneumoniae in Ghanaian children less than six years of age. BMC Infect Dis 2013; 13:490. [PMID: 24148091 PMCID: PMC4015758 DOI: 10.1186/1471-2334-13-490] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 10/15/2013] [Indexed: 11/29/2022] Open
Abstract
Background The objective of this study was to determine the prevalence of nasopharyngeal carriage, serotype distribution, and penicillin resistance of Streptococcus pneumoniae in children ≤6 years of age in Ghana. Methods A cross-sectional study was carried out on a cluster-randomized sample of children ≤6 years of age attending nurseries and kindergartens in Accra and Tamale, Ghana. Basic data on age, sex and exposure to antimicrobials in the previous month were collected on all study subjects. Nasopharyngeal swabs were obtained from participants and all pneumococcal isolates were characterized by serotyping and their penicillin resistance determined. Results The overall prevalence of pneumococcal carriage among the children was 34% in Accra and 31% in Tamale. The predominant serotypes were 19F, 6B, 23F, and 6A with 23% of the isolates being non-typable in Accra and 12% in Tamale. Only two isolates (serotypes 19F and 6B) from Tamale had a MIC >2 μg/ml and were classified as fully penicillin resistant with 45% of the isolates having intermediate resistance. Conclusions These findings indicate that the 13-valent pneumococcal conjugate vaccine (PCV-13) recently introduced in Ghana will cover 48% and 51% of the serotypes identified in Accra and Tamale, respectively. The 23-valent pneumococcal polysaccharide vaccine (PPV-23) will cover 54% of all serotypes detected. The two penicillin resistant isolates (MIC 32 μg/ml) were serotypes included in both PCV-13 and PPV-23. A nationwide monitoring system of penicillin susceptibility patterns and pneumococcal serotypes is recommended.
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Affiliation(s)
| | | | | | | | | | | | - Hans-Christian Slotved
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark.
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Assefa A, Gelaw B, Shiferaw Y, Tigabu Z. Nasopharyngeal carriage and antimicrobial susceptibility pattern of Streptococcus pneumoniae among pediatric outpatients at Gondar University Hospital, North West Ethiopia. Pediatr Neonatol 2013; 54:315-21. [PMID: 23680262 DOI: 10.1016/j.pedneo.2013.03.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 02/04/2013] [Accepted: 04/02/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Pneumonia caused by Streptococcus pneumoniae is the leading cause of death among children in Ethiopia. S. pneumoniae nasopharyngeal carriage can result in endogenous infections and bacterial spread in the community. S. pneumoniae drug resistance is rapidly increasing worldwide. The aim of the study was to assess the nasopharyngeal carriage and antimicrobial susceptibility pattern of S. pneumoniae among pediatric outpatients. METHODS A cross-sectional study was conducted on children aged ≤10 years from February to May of 2012. Data on potential risk factors were gathered using an interview-based questionnaire. Nasopharyngeal specimens were collected with a sterile plastic cotton tip swab. Bacteria were characterized by colony appearance, Gram staining, and optochin susceptibility and bile solubility tests. An antimicrobial susceptibility test was performed using the disk diffusion method. A logistic regression analysis was used to examine the possible risk factors. All tests with p value less than 0.05 were considered statistically significant. RESULTS Of the 234 children screened, 41.03% carried S. pneumoniae. Age-related downward trend for S. pneumoniae carriages (50.9% in <3-year-olds, 40.7% in 3- to 5-year-olds, 40.0% in 5- to <8-year-olds, and 33.3% in 8- to 10-year-olds) were observed. Children living with siblings < 5 years old (p = 0.003) and in a house having one room (p = 0.004) were associated with higher S. pneumoniae carriage. S. pneumoniae showed 33.2% resistance to erythromycin and tetracycline, 29.2% to cotrimoxazole, 14.6% to chloramphenicol and ciprofloxacin, and 10.4% to penicillin. CONCLUSION The S. pneumoniae carriage rate was higher among younger children. High antimicrobial resistance of S. pneumoniae against erythromycin, tetracycline, and cotrimoxazole was observed. Being in the young age group and living with younger children are risk factors for pneumococcal carriage.
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Affiliation(s)
- Abate Assefa
- Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
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Verhagen LM, Gómez-Castellano K, Snelders E, Rivera-Olivero I, Pocaterra L, Melchers WJ, de Waard JH, Hermans PW. Respiratory infections in Eñepa Amerindians are related to malnutrition and Streptococcus pneumoniae carriage. J Infect 2013; 67:273-81. [PMID: 23796866 PMCID: PMC7173337 DOI: 10.1016/j.jinf.2013.06.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/09/2013] [Accepted: 06/12/2013] [Indexed: 01/07/2023]
Abstract
OBJECTIVES High acute respiratory tract infection (ARTI) rates are observed in indigenous populations. We assessed the role of viral infections and nasopharyngeal bacterial carriage in ARTIs in Eñepa Amerindians from Venezuela. METHODS In 40 children aged 0-10 years with ARTIs, healthy nearest-age sibling controls and their mothers the presence of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydophila pneumoniae/psittachi and 15 respiratory viruses was investigated. RESULTS S. pneumoniae was the most frequently detected pathogen, with carriage rates of 75% and 38% in children and mothers respectively. In children, S. pneumoniae carriage was associated with ARTI risk in multivariate analysis (OR 14.1, 95% CI 1.4-137.7). Viral infections were not associated with ARTI risk. S. pneumoniae carriage was common in children of all ages while viral co-infections were more frequently present in children under 4 years compared to older children (46% vs. 17%, p < 0.01). An increase of one unit height-for-age Z score (i.e. improved chronic nutritional status) was associated with decreased odds of S. pneumoniae colonization in multivariate analysis (OR 0.66, 95% CI 0.44-0.99). CONCLUSIONS In Eñepa children high S. pneumoniae carriage rates associated with a poor nutritional status contribute to the development of ARTIs.
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Affiliation(s)
- Lilly M. Verhagen
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, PO Box 9101 (Internal Post 224), 6500 HB Nijmegen, The Netherlands
- Laboratorio de Tuberculosis, Instituto de Biomedicina, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Keyla Gómez-Castellano
- Laboratorio de Tuberculosis, Instituto de Biomedicina, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Eveline Snelders
- Department of Medical Microbiology, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Ismar Rivera-Olivero
- Laboratorio de Tuberculosis, Instituto de Biomedicina, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Leonor Pocaterra
- Catédra de Parasitología, Escuela de Medicina José María Vargas, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Willem J.G. Melchers
- Department of Medical Microbiology, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Jacobus H. de Waard
- Laboratorio de Tuberculosis, Instituto de Biomedicina, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Peter W.M. Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, PO Box 9101 (Internal Post 224), 6500 HB Nijmegen, The Netherlands
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Krone CL, van de Groep K, Trzciński K, Sanders EAM, Bogaert D. Immunosenescence and pneumococcal disease: an imbalance in host-pathogen interactions. THE LANCET RESPIRATORY MEDICINE 2013; 2:141-53. [PMID: 24503269 DOI: 10.1016/s2213-2600(13)70165-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Respiratory infections are among the most important causes of morbidity and mortality from infectious diseases worldwide. The most common causative bacterium, Streptococcus pneumoniae, frequently colonises the upper respiratory tract, where it resides mostly asymptomatically. Occasionally, however, S pneumoniae can cause severe disease such as pneumonia. Local host immunity is essential to control colonising pathogens by preventing overgrowth, spread, and invasion. However, age-related immune deficits in elderly people, known as immunosenescence, might contribute to increased disease burden. We review present knowledge about immunosenescence in the respiratory tract against Gram-positive bacteria, particularly S pneumoniae. We discuss the possible underdetection of pneumococcal colonisation in elderly people, and suggest changes to present surveillance methods to improve understanding of the relation between colonisation and disease. We conclude that present knowledge about alteration of host-pathogen interactions by immunosenescence in the respiratory tract is insufficient, and that research is needed to enable improved measures for prevention.
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Affiliation(s)
- Cassandra L Krone
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Kirsten van de Groep
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Krzysztof Trzciński
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Elizabeth A M Sanders
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands
| | - Debby Bogaert
- Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, WKZ, Utrecht, Netherlands.
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Hare KM, Singleton RJ, Grimwood K, Valery PC, Cheng AC, Morris PS, Leach AJ, Smith-Vaughan HC, Chatfield M, Redding G, Reasonover AL, McCallum GB, Chikoyak L, McDonald MI, Brown N, Torzillo PJ, Chang AB. Longitudinal nasopharyngeal carriage and antibiotic resistance of respiratory bacteria in indigenous Australian and Alaska native children with bronchiectasis. PLoS One 2013; 8:e70478. [PMID: 23940582 PMCID: PMC3734249 DOI: 10.1371/journal.pone.0070478] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 06/20/2013] [Indexed: 11/19/2022] Open
Abstract
Background Indigenous children in Australia and Alaska have very high rates of chronic suppurative lung disease (CSLD)/bronchiectasis. Antibiotics, including frequent or long-term azithromycin in Australia and short-term beta-lactam therapy in both countries, are often prescribed to treat these patients. In the Bronchiectasis Observational Study we examined over several years the nasopharyngeal carriage and antibiotic resistance of respiratory bacteria in these two PCV7-vaccinated populations. Methods Indigenous children aged 0.5–8.9 years with CSLD/bronchiectasis from remote Australia (n = 79) and Alaska (n = 41) were enrolled in a prospective cohort study during 2004–8. At scheduled study visits until 2010 antibiotic use in the preceding 2-weeks was recorded and nasopharyngeal swabs collected for culture and antimicrobial susceptibility testing. Analysis of respiratory bacterial carriage and antibiotic resistance was by baseline and final swabs, and total swabs by year. Results Streptococcus pneumoniae carriage changed little over time. In contrast, carriage of Haemophilus influenzae declined and Staphylococcus aureus increased (from 0% in 2005–6 to 23% in 2010 in Alaskan children); these changes were associated with increasing age. Moraxella catarrhalis carriage declined significantly in Australian, but not Alaskan, children (from 64% in 2004–6 to 11% in 2010). While beta-lactam antibiotic use was similar in the two cohorts, Australian children received more azithromycin. Macrolide resistance was significantly higher in Australian compared to Alaskan children, while H. influenzae beta-lactam resistance was higher in Alaskan children. Azithromycin use coincided significantly with reduced carriage of S. pneumoniae, H. influenzae and M. catarrhalis, but increased carriage of S. aureus and macrolide-resistant strains of S. pneumoniae and S. aureus (proportion of carriers and all swabs), in a ‘cumulative dose-response’ relationship. Conclusions Over time, similar (possibly age-related) changes in nasopharyngeal bacterial carriage were observed in Australian and Alaskan children with CSLD/bronchiectasis. However, there were also significant frequency-dependent differences in carriage and antibiotic resistance that coincided with azithromycin use.
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Affiliation(s)
- Kim M Hare
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
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Gaillat J. Compared effectiveness of the 7-valent pneumococcal conjugate vaccine in children with the 13-valent vaccine in adults. Med Mal Infect 2013; 43:215-21. [PMID: 23769155 DOI: 10.1016/j.medmal.2013.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 02/04/2013] [Accepted: 04/25/2013] [Indexed: 11/15/2022]
Abstract
13-valent-pneumococcal conjugated vaccine was recently approved in the USA and Europe for adults 50 years of age or more. But this approval was followed by recommendations limiting its use to immunocompromised and asplenic patients. The extension of indications to adults was based on the well-demonstrated clinical effectiveness in infants less than 2 years of age, and on a better immune response either quantitatively or qualitatively with conjugated vaccines compared to the immunogenicity of plain polysaccharide vaccines. Nevertheless, the issue was to know whether results observed with the 7-valent pneumococcal conjugate vaccine in children are reproducible in adults with the 13-valent. The answer was given by comparing the epidemiological and physiopathological data, and the immunological response of the two populations. Very few clinical effectiveness studies in adults are available. We had for aim to assess these various issues in infants and adults. A lot of questions remain, such as the unknown impact of serotype replacement with the 13-valent pneumococcal conjugated vaccine on the clinical epidemiology and emergent Streptococcus pneumoniae pathogenicity, while waiting for the CAPITA study results expected in 2014.
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Affiliation(s)
- J Gaillat
- Service des maladies infectieuses, infectiologie, centre hospitalier de la région d'Annecy, 1, avenue de l'Hôpital-Metz-Tessy, BP 90074, 74374 Pringy cedex, France.
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Githii S, Revathi G, Muigai A, Kariuki S. Carriage rate and serotypes of Streptococcus pneumoniae amongst children in Thika Hospital, Kenya. Afr J Lab Med 2013; 2:45. [PMID: 29043160 PMCID: PMC5637771 DOI: 10.4102/ajlm.v2i1.45] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 09/20/2012] [Indexed: 11/06/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. Rates of carriage are highest in infants and the elderly. The objectives of this study were to determine the rate of nasopharyngeal colonization by S. pneumoniae, and to describe the antibiotic resistant patterns and the serotypes of the carried isolates. A cross-sectional study design was used. Nasopharyngeal swabs were collected from 315 children in the months of October and November 2010 and processed to isolate S. pneumoniae. The isolates were serotyped by the Quellung reaction and their antibiotic susceptibilities assessed by the disc diffusion method. The overall nasopharyngeal carriage rate for S. pneumoniae was 17%. Seventeen serotypes were detected amongst 55 strains analysed: 6A, 23F, 19F, 13, 6B, 14A, 20, 7C, 1, 15B, 35B, 19A, 11A, 34, 5, 3 and 23A. Susceptibility testing revealed that nearly all (98%) were resistant to cotrimoxazole, 9% were resistant to penicillin and 7% to cefotaxime. Resistance to chloramphenicol and erythromycin was 2% and 4%, respectively. All isolates were fully sensitive to tetracycline. High levels of cotrimoxazole resistance and some resistance to other antimicrobial agents commonly used in Thika District Hospital shows that there is need to revise antimicrobial policy in this region in the treatment of invasive pneumococcal infections. The frequent serotypes found in this study have previously been associated with pneumococcal infections in children. Several of these serotypes are included in the ten-valent vaccine and therefore use of this vaccine will help reduce pneumococcal infections in Thika.
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Affiliation(s)
- Susan Githii
- Jomo Kenyatta University of Agriculture and Technology, Itromid KEMRI, Kenya
| | | | - Anne Muigai
- Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
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85
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Acquisition of Streptococcus pneumoniae in pneumococcal conjugate vaccine-naïve South African children and their mothers. Pediatr Infect Dis J 2013; 32:e192-205. [PMID: 23340555 DOI: 10.1097/inf.0b013e31828683a3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Pneumococcal nasopharyngeal colonization is a prerequisite to developing pneumococcal disease. We investigated the dynamics of pneumococcal colonization in perinatal HIV-unexposed and HIV-exposed children and their mothers and risk factors associated with new serotypes acquisition. METHODS Two hundred forty-three mother-child pairs (120 HIV-infected, 123 HIV-uninfected mothers) were studied at 4.4, 7.2, 9.4, 12.3 and 16.0 months of the child's age. Demographic data, nasopharyngeal swabs, as well as oropharyngeal swabs, from mothers were collected for pneumococcal conventional culture and serotyping by the Quellung method. RESULTS The rate of new serotype acquisition during the 16 months did not differ between HIV-exposed (49.1%) and HIV-unexposed (52.0%) children, or between HIV-infected (18.9%) and HIV-uninfected (19.5%) mothers. Serotypes included in the 7-valent pneumococcal conjugate vaccine (PCV7) were acquired more often by HIV-infected (10.0%) compared with HIV-uninfected mothers (6.4%; P = 0.03). On multivariate analysis, day-care attendance (adjusted odds ratio [AOR], = 1.80, P = 0.02) and maternal pneumococcal colonization (AOR = 1.54, P = 0.01) were positively associated with pneumococcal acquisition in the child, whereas breast-feeding had a protective effect on PCV7-serotype acquisition in HIV-uninfected children. New acquisition of PCV7 and PCV13 serotypes in the mother was positively associated with colonization in the child (AOR = 2.01, P = 0.006 and AOR = 2.04, P = 0.002, respectively). CONCLUSIONS There is an association of acquisition of PCV7 and PCV13 serotypes between young children and their mothers. The higher prevalence of PCV7 serotype in HIV-infected mothers suggests that they may be a reservoir for transmission of these serotypes, which could delay indirect effects of PCV in settings with a high HIV burden.
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86
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Trzciński K, Bogaert D, Wyllie A, Chu MLJN, van der Ende A, Bruin JP, van den Dobbelsteen G, Veenhoven RH, Sanders EAM. Superiority of trans-oral over trans-nasal sampling in detecting Streptococcus pneumoniae colonization in adults. PLoS One 2013; 8:e60520. [PMID: 23555985 PMCID: PMC3610877 DOI: 10.1371/journal.pone.0060520] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 02/28/2013] [Indexed: 11/18/2022] Open
Abstract
The human nasopharynx is the main reservoir for Streptococcus pneumoniae. We applied conventional and molecular methods to determine the prevalence of S. pneumoniae nasopharyngeal colonization in adults. Paired trans-orally and trans-nasally obtained nasopharyngeal samples from 268 parents of 24-month-old children were assessed for pneumococcal presence. Parents were classified as colonized when live pneumococci were recovered from either sample cultured on medium selective for S. pneumoniae. Of the 52 (19%) colonized parents 49 (18%) were culture-positive in trans-nasal and 10 (4%) in trans-oral samples. Bacterial growth was harvested from these cultures, DNA isolated and tested by quantitative-PCR (qPCR) targeting lytA and piaA genes specific for S. pneumoniae. A sample was considered positive if signals for both genes were detected. Altogether 105 (39%) individuals were classified as positive for pneumococcus by qPCR including 50 (19%) in trans-nasal and 94 (35%) in trans-oral settings. Although significantly more trans-nasal compared to trans-oral samples were culture-positive for S. pneumoniae at the primary diagnostic step (p<0.001) the opposite was observed in qPCR results (p<0.001). To confirm the presence of live pneumococcus in samples positive by qPCR but negative at the initial diagnostic step, we serially-diluted cell harvests, re-cultured and carefully examined for S. pneumoniae presence. Live pneumococci were recovered from an additional 43 parents including 42 positive in trans-oral and 4 in trans-nasal samples increasing the number of individuals culture- and qPCR-positive to 93 (35%) and positive by either of two methods to 107 (40%). There were significantly more trans-oral than trans-nasal samples positive for pneumococcus by both culture and qPCR (n = 71; 27%; vs. n = 50; 19%; p<0.05). Our data suggest that pneumococcal colonization is more common in adults than previously estimated and point towards the superiority of a trans-oral over a trans-nasal approach when testing adults for colonization with S. pneumoniae.
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Affiliation(s)
- Krzysztof Trzciński
- Department of Pediatric Immunology and Infectious Diseases, Wilhelmina's Children Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
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87
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Dunne EM, Smith-Vaughan HC, Robins-Browne RM, Mulholland EK, Satzke C. Nasopharyngeal microbial interactions in the era of pneumococcal conjugate vaccination. Vaccine 2013; 31:2333-42. [PMID: 23523773 DOI: 10.1016/j.vaccine.2013.03.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 02/27/2013] [Accepted: 03/12/2013] [Indexed: 02/07/2023]
Abstract
The nasopharynx of children is often colonised by microorganisms such as Streptococcus pneumoniae (the pneumococcus) that can cause infections including pneumonia and otitis media. In this complex environment, bacteria and viruses may impact each other through antagonistic as well as synergistic interactions. Vaccination may alter colonisation dynamics, evidenced by the rise in non-vaccine serotypes following pneumococcal conjugate vaccination. Discovery of an inverse relationship between S. pneumoniae and Staphylococcus aureus carriage generated concern that pneumococcal vaccination could increase S. aureus carriage and disease. Here we review data on co-colonisation of pathogens in the nasopharynx, focusing on S. pneumoniae and the impact of pneumococcal vaccination. Thus far, pneumococcal vaccination has not had a sustained impact on S. aureus carriage but it is associated with an increase in non-typeable Haemophilus influenzae in acute otitis media aetiology. Advances in bacterial and viral detection methodologies have facilitated research in nasopharyngeal microbiology and will aid investigation of potential vaccine-induced changes, particularly when baseline studies can be conducted prior to pneumococcal vaccine introduction.
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Affiliation(s)
- Eileen M Dunne
- Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.
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88
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Density interactions among Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus in the nasopharynx of young Peruvian children. Pediatr Infect Dis J 2013; 32:72-7. [PMID: 22935873 PMCID: PMC3525793 DOI: 10.1097/inf.0b013e318270d850] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus are commonly carried in the nasopharynx of young children, and have been speculated to interact with each other. Although earlier studies used cultures alone to assess these interactions, the addition of real-time quantitative polymerase chain reaction (qPCR) provides further insight into these interactions. We compared results of culture and qPCR for the detection of these 3 bacteria in 446 nasopharynx samples collected from 360 healthy young children in a prospective cohort study in the Peruvian Andes. Patterns of concurrent bacterial colonization were studied using repeated measures logistic regression models with generalized estimating equations. Spearman correlation coefficients were used to assess correlations among bacterial densities. At a bacterial density <10 colony forming units/mL measured by qPCR, culture detected significantly less carriers (P < 0.0001) for all 3 pathogens, than at a bacterial density >10 colony forming units/mL. In addition, there was a positive association between S. pneumoniae and H. influenzae colonization measured by both culture (odds ratio [OR] 3.11-3.17, P < 0.001) and qPCR (OR 1.95-1.97, P < 0.01). The densities of S. pneumoniae and H. influenzae, measured by qPCR, were positively correlated (correlation coefficient 0.32, P < 0.001). A negative association was found between the presence of S. pneumoniae and Staphylococcus aureus in carriage with both culture (OR 0.45, P = 0.024) and qPCR (OR 0.61, P < 0.05). The impact of density on detection by culture and the observed density-related interactions support use of qPCR in additional studies to examine vaccine effects on diverse bacterial species.
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89
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Song JY, Nahm MH, Moseley MA. Clinical implications of pneumococcal serotypes: invasive disease potential, clinical presentations, and antibiotic resistance. J Korean Med Sci 2013; 28:4-15. [PMID: 23341706 PMCID: PMC3546102 DOI: 10.3346/jkms.2013.28.1.4] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 11/08/2012] [Indexed: 12/27/2022] Open
Abstract
Streptococcus pneumoniae can asymptomatically colonize the nasopharynx and cause a diverse range of illnesses. This clinical spectrum from colonization to invasive pneumococcal disease (IPD) appears to depend on the pneumococcal capsular serotype rather than the genetic background. According to a literature review, serotypes 1, 4, 5, 7F, 8, 12F, 14, 18C, and 19A are more likely to cause IPD. Although serotypes 1 and 19A are the predominant causes of invasive pneumococcal pneumonia, serotype 14 remains one of the most common etiologic agents of non-bacteremic pneumonia in adults, even after 7-valent pneumococcal conjugate vaccine (PCV7) introduction. Serotypes 1, 3, and 19A pneumococci are likely to cause empyema and hemolytic uremic syndrome. Serotype 1 pneumococcal meningitis is prevalent in the African meningitis belt, with a high fatality rate. In contrast to the capsule type, genotype is more closely associated with antibiotic resistance. CC320/271 strains expressing serotype 19A are multidrug-resistant (MDR) and prevalent worldwide in the era of PCV7. Several clones of MDR serotype 6C pneumococci emerged, and a MDR 6D clone (ST282) has been identified in Korea. Since the pneumococcal epidemiology of capsule types varies geographically and temporally, a nationwide serosurveillance system is vital to establishing appropriate vaccination strategies for each country.
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Affiliation(s)
- Joon Young Song
- Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
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90
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Pneumococcal serotype distribution among meningitis cases from Togo and Burkina Faso during 2007–2009. Vaccine 2012; 30 Suppl 6:G41-5. [DOI: 10.1016/j.vaccine.2012.10.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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91
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Cobey S, Lipsitch M. Pathogen diversity and hidden regimes of apparent competition. Am Nat 2012; 181:12-24. [PMID: 23234842 DOI: 10.1086/668598] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Competition through cross-reacting host immune responses, a form of apparent competition, is a major driver of pathogen evolution and diversity. Most models of pathogens have focused on intraspecific interactions to explain observed patterns. Two recent experiments suggested that Haemophilus influenzae, a common nasopharyngeal colonizer of humans, might alter the immune environment in a way that favors otherwise less fit serotypes of another common pathogen, pneumococcus. Using a computational model, we demonstrate that H. influenzae, if it consistently raises the fitness of the less fit serotypes, can strongly promote pneumococcal diversity. However, the effects of H. influenzae are so sensitive to the prevalence of H. influenzae that this species is unlikely to be the main driver of serotype coexistence. Interactions that significantly affect diversity could furthermore be extremely difficult to detect through co-occurrence analysis alone. These results suggest that small differences in strains' adaptations to different immunological regimes, which are shaped by coinfections with other pathogens, can have dramatic effects on strain dynamics and patterns of phenotypic variation. Studies of microbial communities might therefore benefit from the use of varied approaches to infer the presence of indirect interactions.
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Affiliation(s)
- Sarah Cobey
- Center for Communicable Disease Dynamics, Harvard School of Public Health, 677 Huntington Avenue, Boston, Massachusetts 02115, USA.
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92
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Schaumburg F, Alabi A, von Eiff C, Flamen A, Traore H, Grobusch MP, Peters G, Kremsner PG, van der Linden M. Streptococcus pneumoniae colonization in remote African Pygmies. Trans R Soc Trop Med Hyg 2012; 107:105-9. [PMID: 23222951 DOI: 10.1093/trstmh/trs018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND African Pygmies have many risk factors for invasive pneumococcal disease (IPD), such as low socioeconomic status and low quality of health care. We characterized Streptococcus pneumoniae from Gabonese Pygmies and analyzed risk factors for S. pneumoniae carriage to improve prophylaxis and therapy of IPD in this neglected, remotely living African community. METHODS Nasopharyngeal carriage of S. pneumoniae, susceptibility, serotypes and risk factors for IPD were assessed in 103 Pygmies in a cross-sectional study. RESULTS The carriage rate was 37% (n = 38), with the highest proportion (79%, n = 11) in children between two and four years (n = 14). The predominant serotypes were 15A (24%, n = 9), 11A (16%, n = 6) and 6A (13%, n = 5). Non-susceptibility was detected against penicillin (Clinical and Laboratory Standards Institute; CLSI) meningitis breakpoints; (18%, n = 7), trimethoprim/sulfamethoxazole (61%, n = 23), tetracycline (55%, n = 21) and chloramphenicol (3%, n = 1). Among adult participants (n = 51), 69% (n = 35) regularly consumed alcohol and 75% (n = 38) reported to smoke cigarettes. CONCLUSION The high proportion of nicotine and drug abuse might increase the risk of IPD. The unusual serotypes challenge a broad coverage by currently marketed vaccines; the broad antibiotic resistance limits the choice of therapy for S. pneumoniae infection.
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93
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Cevallos V, Whitcher JP, Melese M, Alemayehu W, Yi E, Chidambaram JD, Lee S, Reddy H, Gaynor BD, Lietman TM, Keenan JD. Association of conjunctival bacterial infection and female sex in cicatricial trachoma. Invest Ophthalmol Vis Sci 2012; 53:5208-12. [PMID: 22736616 DOI: 10.1167/iovs.12-9984] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
PURPOSE Conjunctival infection with non-chlamydial bacteria may play an important role in the progression of trachoma, especially with regard to the development of corneal opacity and blindness. To further characterize the microbiological profile of bacterial conjunctival infections in cicatricial trachoma, a conjunctival swabbing of adults in rural Ethiopia was performed. METHODS In a cross-sectional study conducted in nine Ethiopian villages with hyperendemic trachoma, persons 40 years of age or older with signs or symptoms consistent with trichiasis were recruited and conjunctival swabbing for bacterial pathogens was performed. RESULTS Conjunctival examination and swabbing on 112 females and 36 males were performed. Of the 148 study participants, 101 (68.2%) were confirmed to have trichiasis, and 118 (80%) had conjunctival swabs positive for bacteria. In multivariate analyses, growth of pathogenic conjunctival bacteria was independently associated with trichiasis (odds ratio [OR] 6.93; 95% confidence interval [CI] 2.71-17.7) and female sex (OR 5.90; 95% CI 2.09-16.7). Females were more likely to have swabs positive for Streptococcus pneumoniae or Haemophilus influenzae than were males (OR 9.09; 95% CI 1.17-70.8). CONCLUSIONS In a region of Ethiopia with endemic trachoma, conjunctival bacterial growth was more common in females than that in males. S. pneumoniae and H. influenzae, both of which frequently colonize the nasopharynx of children, were more common in females, suggesting that the preponderance of infection in females may be attributable to close contact with children. This finding is consistent with the theory that childcare activities may preferentially expose females to ocular chlamydial infection. (ClinicalTrials.gov number, NCT00221364.).
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Affiliation(s)
- Vicky Cevallos
- Francis I. Proctor Foundation, San Francisco, California 94143-0412, USA
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94
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Tenenbaum T, Franz A, Neuhausen N, Willems R, Brade J, Schweitzer-Krantz S, Adams O, Schroten H, Henrich B. Clinical characteristics of children with lower respiratory tract infections are dependent on the carriage of specific pathogens in the nasopharynx. Eur J Clin Microbiol Infect Dis 2012; 31:3173-82. [DOI: 10.1007/s10096-012-1682-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 06/11/2012] [Indexed: 10/28/2022]
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95
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Abdullahi O, Karani A, Tigoi CC, Mugo D, Kungu S, Wanjiru E, Jomo J, Musyimi R, Lipsitch M, Scott JAG. Rates of acquisition and clearance of pneumococcal serotypes in the nasopharynges of children in Kilifi District, Kenya. J Infect Dis 2012; 206:1020-9. [PMID: 22829650 PMCID: PMC3433858 DOI: 10.1093/infdis/jis447] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background. To understand and model the impact of pneumococcal conjugate vaccines at the population level, we need to know the transmission dynamics of individual pneumococcal serotypes. We estimated serotype-specific clearance and acquisition rates of nasopharyngeal colonization among Kenyan children. Methods. Children aged 3–59 months who were identified as carriers in a cross-sectional survey were followed-up approximately 1, 2, 4, 8, 16, and 32 days later and monthly thereafter until culture of 2 consecutive swabs yielded an alternative serotype or no pneumococcus. Serotype-specific clearance rates were estimated by exponential regression of interval-censored carriage durations. Duration was estimated as the reciprocal of the clearance rate, and acquisition rates were estimated on the basis of prevalence and duration, assuming an equilibrium state. Results. Of 2840 children sampled between October 2006 and December 2008, 1868 were carriers. The clearance rate was 0.032 episodes/day (95% confidence interval [CI], .030–.034), for a carriage duration of 31.3 days, and the rate varied by serotype (P < .0005). Carriage durations for the 28 serotypes with ≥10 carriers ranged from 6.7 to 50 days. Clearance rates increased with year of age, adjusted for serotype (hazard ratio, 1.21; 95% CI, 1.15–1.27). The acquisition rate was 0.061 episodes/day (95% CI, .055–.067), which did not vary with age. Serotype-specific acquisition rates varied from 0.0002 to 0.0022 episodes/day. Serotype-specific acquisition rates correlated with prevalence (r = 0.91; P < .00005) and with acquisition rates measured in a separate study involving 1404 newborns in Kilifi (r = 0.87; P < .00005). Conclusions. The large sample size and short swabbing intervals provide a precise description of the prevalence, duration, and acquisition of carriage of 28 pneumococcal serotypes. In Kilifi, young children experience approximately 8 episodes of carriage per year. The declining prevalence with age is attributable to increasing clearance rates.
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Affiliation(s)
- Osman Abdullahi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.
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96
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Moyo SJ, Steinbakk M, Aboud S, Mkopi N, Kasubi M, Blomberg B, Manji K, Lyamuya EF, Maselle SY, Langeland N. Penicillin resistance and serotype distribution of Streptococcus pneumoniae in nasopharyngeal carrier children under 5 years of age in Dar es Salaam, Tanzania. J Med Microbiol 2012; 61:952-959. [DOI: 10.1099/jmm.0.042598-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Sabrina J. Moyo
- Institute of Medicine, University of Bergen, N-5021 Bergen, Norway
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Martin Steinbakk
- Department of Bacteriology and Immunology, Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway
| | - Said Aboud
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Namala Mkopi
- Department of Paediatrics and Child Health, Muhimbili National Hospital, Dar es Salaam, Tanzania
| | - Mabula Kasubi
- Department of Microbiology and Immunology, Muhimbili National Hospital, Dar es Salaam, Tanzania
| | - Bjorn Blomberg
- Department of Medicine, Haukeland University Hospital, N-5021 Bergen, Norway
- Institute of Medicine, University of Bergen, N-5021 Bergen, Norway
| | - Karim Manji
- Department of Paediatrics and Child Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Eligius F. Lyamuya
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Samuel Y. Maselle
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Nina Langeland
- Institute of Medicine, University of Bergen, N-5021 Bergen, Norway
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97
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Roca A, Bottomley C, Hill PC, Bojang A, Egere U, Antonio M, Darboe O, Greenwood BM, Adegbola RA. Effect of age and vaccination with a pneumococcal conjugate vaccine on the density of pneumococcal nasopharyngeal carriage. Clin Infect Dis 2012; 55:816-24. [PMID: 22700830 PMCID: PMC3423933 DOI: 10.1093/cid/cis554] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
This study evaluated the impact of age and pneumococcal vaccination on the density of pneumococcal nasopharyngeal carriage. Among colonized individuals, density decreased with increasing age. Time-trends analysis revealed that pneumococcal vaccination appeared to lower the density of nasopharyngeal carriage. Background. This study evaluated the impact of age and pneumococcal vaccination on the density of pneumococcal nasopharyngeal carriage. Methods. A cluster-randomized trial was conducted in rural Gambia. In 11 villages (the vaccine group), all residents received 7-valent pneumococcal conjugate vaccine (PCV-7), while in another 10 villages (the control group), only children <30 months old or born during the study period received PCV-7. Cross-sectional surveys (CSSs) were conducted to collect nasopharyngeal swabs before vaccination (baseline CSS) and 4, 12, and 22 months after vaccination. Pneumococcal density was defined using a semiquantitative classification (range, 1–4) among colonized individuals. An age-trend analysis of density was conducted using data from the baseline CSS. Mean pneumococcal density was compared in CSSs conducted before and after vaccination. Results. Mean bacterial density among colonized individuals in the baseline CSS was 2.57 for vaccine-type (VT) and non–vaccine-type (NVT) pneumococci; it decreased with age (P < .001 for VT and NVT). There was a decrease in the density of VT carriage following vaccination in individuals older than 5 years (from 2.44 to 1.88; P = .001) and in younger individuals (from 2.57 to 2.11; P = .070) in the vaccinated villages. Similar decreases in density were observed with NVT within vaccinated and control villages. No significant differences were found between vaccinated and control villages in the postvaccination comparisons for either VT or NVT. Conclusions. A high density of carriage among young subjects might partly explain why children are more efficient than adults in pneumococcal transmission. PCV-7 vaccination lowered the density of VT and of NVT pneumococcal carriage in the before-after vaccination analysis. Clinical Trials Registration. ISRCTN51695599.
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Affiliation(s)
- A Roca
- Medical Research Council Unit, Gambia.
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98
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A longitudinal study of Streptococcus pneumoniae carriage in a cohort of infants and their mothers on the Thailand-Myanmar border. PLoS One 2012; 7:e38271. [PMID: 22693610 PMCID: PMC3365031 DOI: 10.1371/journal.pone.0038271] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/07/2012] [Indexed: 11/19/2022] Open
Abstract
Background Pneumococcal disease is a major cause of childhood death. Almost a third of the world's children live in Southeast Asia, but there are few data from the region on pneumococcal colonization or disease. Our aim was to document the dynamics of pneumococcal carriage in a rural SE Asian birth cohort. Methods We studied 234 Karen mother-infant pairs in Northwestern Thailand. Infants were followed from birth and nasopharyngeal swabs were taken from mother and infant at monthly intervals until 24 months old. Results 8,386 swabs were cultured and 4,396 pneumococci characterized. Infants became colonized early (median 45.5 days; 95% confidence interval [CI] 44.5-46.0) and by 24 months had a median of seven (range 0–15) carriage episodes. Maternal smoking and young children in the house were associated with earlier colonization (hazard ratio [HR] 1.5 (95% CI 1.1–2.1) and 1.4 (95% CI 1.0–1.9)). For the four commonest serotypes and non-typeable pneumococci, previous exposure to homologous or heterologous serotypes resulted in an extended interval to reacquisition of the same serotype. Previous colonization by serotypes 14 and 19F was also associated with reduced carriage duration if subsequently reacquired (HR [first reacquisition] 4.1 (95% CI 1.4–12.6) and 2.6 (1.5–4.7)). Mothers acquired pneumococci less frequently, and carried them for shorter periods, than infants (acquisition rate 0.5 vs. 1.1 /100 person-days, p<0.001; median duration 31.0 vs. 60.5 days, p = 0.001). 55.8% of pneumococci from infants were vaccine serotypes (13-valent pneumococcal conjugate vaccine, PCV13), compared with 27.5% from mothers (p<0.001). Non-typeable pneumococcal carriage was common, being carried at least once by 55.1% of infants and 32.0% of mothers. Conclusions Pneumococcal carriage frequency and duration are influenced by previous exposure to both homologous and heterologous serotypes. These data will inform vaccination strategies in this population.
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99
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Moore SE, Richards AA, Goldblatt D, Ashton L, Szu SC, Prentice AM. Early-life and contemporaneous nutritional and environmental predictors of antibody response to vaccination in young Gambian adults. Vaccine 2012; 30:4842-8. [PMID: 22609011 PMCID: PMC3657163 DOI: 10.1016/j.vaccine.2012.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 04/11/2012] [Accepted: 05/05/2012] [Indexed: 11/26/2022]
Abstract
Recent research links nutritional exposures early in life with alterations in functional immunity that persist beyond childhood. Here we investigate predictors of antibody response to polysaccharide vaccines in a cohort of Gambian adults with detailed records from birth and early infancy available. 320 adults were given a single dose of a Vi polysaccharide vaccine for Salmonella typhi and a 23-valent capsular polysaccharide pneumococcal vaccine. Anti-Vi antibody levels and antibodies against 4 pneumococcal serotypes (1, 5, 14 and 23F) were measured in serum samples collected at baseline and then 14 days following vaccination and compared to data available from birth and early infancy. Post-vaccination antibody titres to serotype 14 of the pneumococcal vaccine were negatively associated with rate of growth from birth to three months of age, infant weight at 12 months of age and season of birth, but no other associations were observed with early-life exposures. The strongest predictor of antibody levels was pre-vaccination antibody titres, with adult height and serum neopterin levels at time of vaccination also implicated. The current study does not support the hypothesis that nutritional exposures early in life consistently compromise antibody response to polysaccharide vaccines administered in young adulthood.
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Affiliation(s)
- Sophie E Moore
- MRC Keneba, Medical Research Council Laboratories, Fajara, Gambia.
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Sequetyping: serotyping Streptococcus pneumoniae by a single PCR sequencing strategy. J Clin Microbiol 2012; 50:2419-27. [PMID: 22553238 DOI: 10.1128/jcm.06384-11] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The introduction of pneumococcal conjugate vaccines necessitates continued monitoring of circulating strains to assess vaccine efficacy and replacement serotypes. Conventional serological methods are costly, labor-intensive, and prone to misidentification, while current DNA-based methods have limited serotype coverage requiring multiple PCR primers. In this study, a computer algorithm was developed to interrogate the capsulation locus (cps) of vaccine serotypes to locate primer pairs in conserved regions that border variable regions and could differentiate between serotypes. In silico analysis of cps from 92 serotypes indicated that a primer pair spanning the regulatory gene cpsB could putatively amplify 84 serotypes and differentiate 46. This primer set was specific to Streptococcus pneumoniae, with no amplification observed for other species, including S. mitis, S. oralis, and S. pseudopneumoniae. One hundred thirty-eight pneumococcal strains covering 48 serotypes were tested. Of 23 vaccine serotypes included in the study, most (19/22, 86%) were identified correctly at least to the serogroup level, including all of the 13-valent conjugate vaccine and other replacement serotypes. Reproducibility was demonstrated by the correct sequetyping of different strains of a serotype. This novel sequence-based method employing a single PCR primer pair is cost-effective and simple. Furthermore, it has the potential to identify new serotypes that may evolve in the future.
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