1
|
Nasher F, Wren BW. Unravelling mechanisms of bacterial recognition by Acanthamoeba: insights into microbial ecology and immune responses. Front Microbiol 2024; 15:1405133. [PMID: 39247694 PMCID: PMC11377244 DOI: 10.3389/fmicb.2024.1405133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 08/08/2024] [Indexed: 09/10/2024] Open
Abstract
Acanthamoeba, are ubiquitous eukaryotic microorganisms, that play a pivotal role in recognizing and engulfing various microbes during predation, offering insights into microbial dynamics and immune responses. An intriguing observation lies in the apparent preference of Acanthamoeba for Gram-negative over Gram-positive bacteria, suggesting potential differences in the recognition and response mechanisms to bacterial prey. Here, we comprehensively review pattern recognition receptors (PRRs) and microbe associated molecular patterns (MAMPs) that influence Acanthamoeba interactions with bacteria. We analyze the molecular mechanisms underlying these interactions, and the key finding of this review is that Acanthamoeba exhibits an affinity for bacterial cell surface appendages that are decorated with carbohydrates. Notably, this parallels warm-blooded immune cells, underscoring a conserved evolutionary strategy in microbial recognition. This review aims to serve as a foundation for exploring PRRs and MAMPs. These insights enhance our understanding of ecological and evolutionary dynamics in microbial interactions and shed light on fundamental principles governing immune responses. Leveraging Acanthamoeba as a model organism, provides a bridge between ecological interactions and immunology, offering valuable perspectives for future research.
Collapse
Affiliation(s)
- Fauzy Nasher
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Brendan W Wren
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| |
Collapse
|
2
|
Xing Y, Duan Z, Jiang Y, Li M, Lu W, Li J. Development and evaluation of a real-time multienzyme isothermal rapid amplification assay for rapid detection of Streptococcus pneumoniae. Sci Rep 2024; 14:17729. [PMID: 39085471 PMCID: PMC11291690 DOI: 10.1038/s41598-024-68524-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 07/24/2024] [Indexed: 08/02/2024] Open
Abstract
Streptococcus pneumoniae is a significant pathogen causing infectious diseases, including pneumonia, otitis media, septicemia, and meningitis. The introduction of multivalent vaccines has coincided with a remarkable decrease in the number of pneumococcal-related deaths. Despite this, pneumococcal infection remains a significant cause of death among children under 5 years old and adults aged 65 or older at a global level. Therefore, early detection of S. pneumoniae infection is crucial for prognosis of pneumococcal infection patients. In this study, we evaluated the utility of a real-time multienzyme isothermal rapid amplification (MIRA) assay for detecting S. pneumoniae and other non-S. pneumoniae bacterial species. A primer-probe set targeting the S. pneumoniae lytA gene was designed, followed by optimization of parameters for the MIRA assay. At the same time, we validated the real-time MIRA assay for detecting S. pneumoniae using 79 clinical isolates identified by VITEK MS. The results showed a detection sensitivity and specificity of 100%. These results demonstrate that the designed real-time MIRA assay is a promising, rapid, simple, and reliable method for detecting S. pneumoniae infection in resource-limited areas. It has great potential for application in detecting not only S. pneumoniae but also other non-S. pneumoniae bacterial species.
Collapse
Affiliation(s)
- Yun Xing
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Zhixiong Duan
- Department of Laboratory Medicine, The Chen Jia Qiao Hospital of Sha Ping Ba District of Chongqing City, Chongqing, China
| | - Yuansu Jiang
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Min Li
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Weiping Lu
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China.
| | - Jin Li
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China.
- Department of Laboratory Medicine, Chongqing Medical University Affiliated Dazu Hospital, Chongqing, China.
| |
Collapse
|
3
|
Pan F, Zhao N, Zhao W, Wang C, Sun Y, Zhang H, Qin J, Liu Q, Zhang H. Performance of Two Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) Systems for Identification of the Viridans Group Streptococci. Infect Drug Resist 2023; 16:2901-2909. [PMID: 37193297 PMCID: PMC10183192 DOI: 10.2147/idr.s407667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/20/2023] [Indexed: 05/18/2023] Open
Abstract
Background Due to similar colony morphology among viridans group streptococci (VGS), the differentiation of VGS species remains difficult in routine clinical microbiology. Recently, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been described as a fast method for identifying various bacteria at species level, and also for the VGS strains. Methods A total of 277 VGS isolates were identified with the two MALDI-TOF MS systems (VITEK MS and Bruker Biotyper). The tuf and rpoB gene sequencing was used as the reference identification method for comparison. Results Based on tuf and rpoB gene sequencing, 84 isolates were S. pneumoniae and 193 strains were other VGS isolates including S. anginosus group (n=91, 47.2%), S. mitis group (n=80, 41.5%), S. bovis group (n=11, 5.7%), S. salivarius group (n=10, 5.2%), and S. mutans group (n=1, 0.5%). VITEK MS and Bruker Biotyper accurately identified 94.6% and 89.9% of all VGS isolates, respectively. VITEK MS showed better identification results than Bruker Biotyper for S. mitis group including S. pneumoniae and S. bovis group, but for other VGS isolates, two MALDI-TOF MS systems showed comparable identification performance. However, VITEK MS was able to identify S. gallolyticus to the subspecies level with high-confidence (S. gallolyticus ssp. pasteurianus), while the Bruker Biotyper system could not. While Bruker Biotyper system could be able to correctly differentiate the subspecies of S. salivarius from S. vestibularis, VITEK MS poorly identify. Conclusion This study demonstrated that two MALDI-TOF MS systems allowed discrimination for most VGS isolates with different identification performance, but Bruker Biotyper could produce more misidentifications and VITEK MS system. It is crucial to be familiar with the performance of MALDI-TOF MS systems used in clinical microbiology.
Collapse
Affiliation(s)
- Fen Pan
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200062, People’s Republic of China
| | - Na Zhao
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, People’s Republic of China
| | - Wantong Zhao
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Chun Wang
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Yan Sun
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Haomin Zhang
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, People’s Republic of China
| | - Juanxiu Qin
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, People’s Republic of China
| | - Qian Liu
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, People’s Republic of China
- Qian Liu, Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, People’s Republic of China, Email
| | - Hong Zhang
- Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200062, People’s Republic of China
- Correspondence: Hong Zhang, Department of Clinical Laboratory, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China, Tel +86 189 1712 8200, Email
| |
Collapse
|
4
|
Absence of Streptococcus pneumoniae Capsule Increases Bacterial Binding, Persistence, and Inflammation in Corneal Infection. Microorganisms 2022; 10:microorganisms10040710. [PMID: 35456761 PMCID: PMC9025271 DOI: 10.3390/microorganisms10040710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 03/07/2022] [Accepted: 03/22/2022] [Indexed: 11/17/2022] Open
Abstract
The role of the pneumococcal polysaccharide capsule is largely unclear for Streptococcus pneumoniae keratitis, an ocular inflammatory disease that develops as a result of bacterial infection of the cornea. In this study, capsule-deficient strains were compared to isogenic parent strains in their ability to adhere to human corneal epithelial cells. One isogenic pair was further used in topical ocular infection of mice to assess the contribution of the capsule to keratitis. The results showed that non-encapsulated pneumococci were significantly more adherent to cells, persisted in significantly higher numbers on mouse corneas in vivo, and caused significant increases in murine ocular IL9, IL10, IL12-p70, MIG, and MIP-1-gamma compared to encapsulated S. pneumoniae. These findings indicate that the bacterial capsule impedes virulence and the absence of capsule impacts inflammation following corneal infection.
Collapse
|
5
|
Ung L, Bispo PJM, Bryan NC, Andre C, Chodosh J, Gilmore MS. The Best of All Worlds: Streptococcus pneumoniae Conjunctivitis through the Lens of Community Ecology and Microbial Biogeography. Microorganisms 2019; 8:microorganisms8010046. [PMID: 31881682 PMCID: PMC7022640 DOI: 10.3390/microorganisms8010046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/16/2019] [Accepted: 12/21/2019] [Indexed: 12/16/2022] Open
Abstract
The study of the forces which govern the geographical distributions of life is known as biogeography, a subject which has fascinated zoologists, botanists and ecologists for centuries. Advances in our understanding of community ecology and biogeography—supported by rapid improvements in next generation sequencing technology—have now made it possible to identify and explain where and why life exists as it does, including within the microbial world. In this review, we highlight how a unified model of microbial biogeography, one which incorporates the classic ecological principles of selection, diversification, dispersion and ecological drift, can be used to explain community dynamics in the settings of both health and disease. These concepts operate on a multiplicity of temporal and spatial scales, and together form a powerful lens through which to study microbial population structures even at the finest anatomical resolutions. When applied specifically to curious strains of conjunctivitis-causing, nonencapsulated Streptococcus pneumoniae, we show how this conceptual framework can be used to explain the possible evolutionary and disease-causing mechanisms which allowed these lineages to colonize and invade a separate biogeography. An intimate knowledge of this radical bifurcation in phylogeny, still the only known niche subspecialization for S. pneumoniae to date, is critical to understanding the pathogenesis of ocular surface infections, nature of host-pathogen interactions, and developing strategies to curb disease transmission.
Collapse
Affiliation(s)
- Lawson Ung
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA; (L.U.); (P.J.M.B.); (C.A.); (J.C.)
- Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
| | - Paulo J. M. Bispo
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA; (L.U.); (P.J.M.B.); (C.A.); (J.C.)
- Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
| | - Noelle C. Bryan
- Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
- Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences, Cambridge, MA 02139, USA
| | - Camille Andre
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA; (L.U.); (P.J.M.B.); (C.A.); (J.C.)
- Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA; (L.U.); (P.J.M.B.); (C.A.); (J.C.)
- Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
| | - Michael S. Gilmore
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA; (L.U.); (P.J.M.B.); (C.A.); (J.C.)
- Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
- Correspondence: ; Tel.: +1-617-523-7900
| |
Collapse
|
6
|
Nasher F, Kwun MJ, Croucher NJ, Heller M, Hathaway LJ. Peptide Occurring in Enterobacteriaceae Triggers Streptococcus pneumoniae Cell Death. Front Cell Infect Microbiol 2019; 9:320. [PMID: 31552200 PMCID: PMC6748166 DOI: 10.3389/fcimb.2019.00320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 08/26/2019] [Indexed: 11/15/2022] Open
Abstract
Non-encapsulated Streptococcus pneumoniae often possess two genes, aliB-like ORF 1 and aliB-like ORF 2, in place of capsule genes. AliB-like ORF 1 is thought to encode a substrate binding protein of an ABC transporter which binds peptide SETTFGRDFN, found in 50S ribosomal subunit protein L4 of Enterobacteriaceae. Here, we investigated the effect of binding of AliB-like ORF 1 peptide on the transcriptome and proteome of non-encapsulated pneumococci. We found upregulation of gene expression of a metacaspase and a gene encoding N-acetylmuramoyl-L-alanine amidase, both of which are proposed to be involved in programmed cell death in prokaryotic cells. Proteome profiling indicated upregulation of transcriptional regulators and downregulation of metabolism-associated genes. Exposure to the peptide specifically triggered death in pneumococci which express AliB-like ORF 1, with the bacteria having an apoptotic appearance by electron microscopy. We propose that binding of the AliB-like ORF 1 peptide ligand by the pneumococcus signals a challenging environment with hostile bacterial species leading to death of a proportion of the pneumococcal population.
Collapse
Affiliation(s)
- Fauzy Nasher
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Min Jung Kwun
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Nicholas J Croucher
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| |
Collapse
|
7
|
Identification of Streptococcus pneumoniae by a real-time PCR assay targeting SP2020. Sci Rep 2019; 9:3285. [PMID: 30824850 PMCID: PMC6397248 DOI: 10.1038/s41598-019-39791-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/21/2019] [Indexed: 11/15/2022] Open
Abstract
Real-time PCR targeting lytA (the major autolysin gene) and piaB (permease gene of the pia ABC transporter) are currently used as the gold-standard culture-independent assays for Streptococcus pneumoniae identification. We evaluated the performance of a new real-time PCR assay – targeting SP2020 (putative transcriptional regulator gene) – and compared its performance with the assays previously described. A collection of 150 pneumococci, 433 non-pneumococci and 240 polymicrobial samples (obtained from nasopharynx, oropharynx, and saliva; 80 from each site) was tested. SP2020 and lytA-CDC assays had the best performance (sensitivity of 100% for each compared to 95.3% for piaB). The specificity for lytA and piaB was 99.5% and for SP2020 was 99.8%. Misidentifications occurred for the three genes: lytA, piaB and SP2020 were found in non-pneumococcal strains; piaB was absent in some pneumococci including a serotype 6B strain. Combining lytA and SP2020 assays resulted in no misidentifications. Most polymicrobial samples (88.8%) yielded concordant results for the three molecular targets. The remaining samples seemed to contain non-typeable pneumococci (0.8%), and non-pneumococci positive for lytA (1.7%) or SP2020 (8.7%). We propose that combined detection of both lytA-CDC and SP2020 is a powerful strategy for the identification of pneumococcus either in pure cultures or in polymicrobial samples.
Collapse
|
8
|
Prevalence of Pneumococcal Nasopharyngeal Carriage Among Children 2-18 Months of Age: Baseline Study Pre Introduction of Pneumococcal Vaccination in Cuba. Pediatr Infect Dis J 2017; 36:e22-e28. [PMID: 27649366 DOI: 10.1097/inf.0000000000001341] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND A new vaccine candidate against pneumococcus is being developed in Cuba, and it is a priority of the national health system. There is limited information on nasopharyngeal colonization burden, though it is essential for monitoring the impact of the vaccine. The study aims to estimate the prevalence of nasopharyngeal colonization in children 2-18 months of age and identify circulating serotypes, antimicrobial resistance and its association with selected risk factors. METHODS A cross-sectional study was conducted between October and December 2013 in Cienfuegos municipality. Inclusion criteria were evaluated, and informed consent was obtained from the parents. Clinical and epidemiologic data were collected through a semistructured questionnaire. Nasopharyngeal swabs according to established protocols were taken. Data analysis included frequency distributions and comparison of proportions. The association between colonization and selected risk factors was assessed by multivariate analysis. RESULTS A total of 984 children (87.2% living in urban areas) were included. The overall prevalence of colonization was 21.6%. The most frequent serotypes isolated were 6A (23.1%), 23F (10.8%), 6B (10.3%), 19F (8.5%) and 14 (3.3%). We found no resistance to β-lactamases in circulating serotypes. Living with sibling younger than 5 years, previous respiratory infections, previous hospitalization and day-care attendance were determinants of nasopharyngeal carriage. CONCLUSIONS The findings suggest that the burden of pneumococcal disease and colonization in Cuba could be significantly affected after vaccine introduction.
Collapse
|
9
|
Abstract
While significant protection from pneumococcal disease has been achieved by the use of polysaccharide and polysaccharide-protein conjugate vaccines, capsule-independent protection has been limited by serotype replacement along with disease caused by nonencapsulated Streptococcus pneumoniae (NESp). NESp strains compose approximately 3% to 19% of asymptomatic carriage isolates and harbor multiple antibiotic resistance genes. Surface proteins unique to NESp enhance colonization and virulence despite the lack of a capsule even though the capsule has been thought to be required for pneumococcal pathogenesis. Genes for pneumococcal surface proteins replace the capsular polysaccharide (cps) locus in some NESp isolates, and these proteins aid in pneumococcal colonization and otitis media (OM). NESp strains have been isolated from patients with invasive and noninvasive pneumococcal disease, but noninvasive diseases, specifically, conjunctivitis (85%) and OM (8%), are of higher prevalence. Conjunctival strains are commonly of the so-called classical NESp lineages defined by multilocus sequence types (STs) ST344 and ST448, while sporadic NESp lineages such as ST1106 are more commonly isolated from patients with other diseases. Interestingly, sporadic lineages have significantly higher rates of recombination than classical lineages. Higher rates of recombination can lead to increased acquisition of antibiotic resistance and virulence factors, increasing the risk of disease and hindering treatment. NESp strains are a significant proportion of the pneumococcal population, can cause disease, and may be increasing in prevalence in the population due to effects on the pneumococcal niche caused by pneumococcal vaccines. Current vaccines are ineffective against NESp, and further research is necessary to develop vaccines effective against both encapsulated and nonencapsulated pneumococci.
Collapse
|
10
|
Srinivasan R, Karaoz U, Volegova M, MacKichan J, Kato-Maeda M, Miller S, Nadarajan R, Brodie EL, Lynch SV. Use of 16S rRNA gene for identification of a broad range of clinically relevant bacterial pathogens. PLoS One 2015; 10:e0117617. [PMID: 25658760 PMCID: PMC4319838 DOI: 10.1371/journal.pone.0117617] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/29/2014] [Indexed: 01/06/2023] Open
Abstract
According to World Health Organization statistics of 2011, infectious diseases remain in the top five causes of mortality worldwide. However, despite sophisticated research tools for microbial detection, rapid and accurate molecular diagnostics for identification of infection in humans have not been extensively adopted. Time-consuming culture-based methods remain to the forefront of clinical microbial detection. The 16S rRNA gene, a molecular marker for identification of bacterial species, is ubiquitous to members of this domain and, thanks to ever-expanding databases of sequence information, a useful tool for bacterial identification. In this study, we assembled an extensive repository of clinical isolates (n = 617), representing 30 medically important pathogenic species and originally identified using traditional culture-based or non-16S molecular methods. This strain repository was used to systematically evaluate the ability of 16S rRNA for species level identification. To enable the most accurate species level classification based on the paucity of sequence data accumulated in public databases, we built a Naïve Bayes classifier representing a diverse set of high-quality sequences from medically important bacterial organisms. We show that for species identification, a model-based approach is superior to an alignment based method. Overall, between 16S gene based and clinical identities, our study shows a genus-level concordance rate of 96% and a species-level concordance rate of 87.5%. We point to multiple cases of probable clinical misidentification with traditional culture based identification across a wide range of gram-negative rods and gram-positive cocci as well as common gram-negative cocci.
Collapse
Affiliation(s)
- Ramya Srinivasan
- University of California San Francisco, Department of Medicine, Gastroenterology Division, 513 Parnassus Ave, San Francisco, CA 94143–0538, United States of America
| | - Ulas Karaoz
- Lawrence Berkeley National Laboratory, Earth Sciences Division, 1 Cyclotron Rd., MS70A-3317, Berkeley, CA 94720, United States of America
| | - Marina Volegova
- University of California, Berkeley, CA 94720, United States of America
| | - Joanna MacKichan
- School of Biological Sciences, Victoria University of Wellington, 34 Kenepuru Drive, Porirua, Wellington, New Zealand
| | - Midori Kato-Maeda
- San Francisco General Hospital, Department of Medicine, Bldg 100, San Francisco, CA 94110, United States of America
| | - Steve Miller
- University of California San Francisco, Clinical Microbiology Laboratory, 185 Berry Street, Suite 290, San Francisco, CA 94107, United States of America
| | - Rohan Nadarajan
- University of California San Francisco, Clinical Microbiology Laboratory, 185 Berry Street, Suite 290, San Francisco, CA 94107, United States of America
| | - Eoin L. Brodie
- Lawrence Berkeley National Laboratory, Earth Sciences Division, 1 Cyclotron Rd., MS70A-3317, Berkeley, CA 94720, United States of America
| | - Susan V. Lynch
- University of California San Francisco, Department of Medicine, Gastroenterology Division, 513 Parnassus Ave, San Francisco, CA 94143–0538, United States of America
- * E-mail:
| |
Collapse
|
11
|
Ramirez M. Streptococcus pneumoniae. MOLECULAR MEDICAL MICROBIOLOGY 2015:1529-1546. [DOI: 10.1016/b978-0-12-397169-2.00086-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
12
|
Hilty M, Wüthrich D, Salter SJ, Engel H, Campbell S, Sá-Leão R, de Lencastre H, Hermans P, Sadowy E, Turner P, Chewapreecha C, Diggle M, Pluschke G, McGee L, Eser ÖK, Low DE, Smith-Vaughan H, Endimiani A, Küffer M, Dupasquier M, Beaudoing E, Weber J, Bruggmann R, Hanage WP, Parkhill J, Hathaway LJ, Mühlemann K, Bentley SD. Global phylogenomic analysis of nonencapsulated Streptococcus pneumoniae reveals a deep-branching classic lineage that is distinct from multiple sporadic lineages. Genome Biol Evol 2014; 6:3281-94. [PMID: 25480686 PMCID: PMC4986459 DOI: 10.1093/gbe/evu263] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2014] [Indexed: 01/08/2023] Open
Abstract
The surrounding capsule of Streptococcus pneumoniae has been identified as a major virulence factor and is targeted by pneumococcal conjugate vaccines (PCV). However, nonencapsulated S. pneumoniae (non-Ec-Sp) have also been isolated globally, mainly in carriage studies. It is unknown if non-Ec-Sp evolve sporadically, if they have high antibiotic nonsusceptiblity rates and a unique, specific gene content. Here, whole-genome sequencing of 131 non-Ec-Sp isolates sourced from 17 different locations around the world was performed. Results revealed a deep-branching classic lineage that is distinct from multiple sporadic lineages. The sporadic lineages clustered with a previously sequenced, global collection of encapsulated S. pneumoniae (Ec-Sp) isolates while the classic lineage is comprised mainly of the frequently identified multilocus sequences types (STs) ST344 (n = 39) and ST448 (n = 40). All ST344 and nine ST448 isolates had high nonsusceptiblity rates to β-lactams and other antimicrobials. Analysis of the accessory genome reveals that the classic non-Ec-Sp contained an increased number of mobile elements, than Ec-Sp and sporadic non-Ec-Sp. Performing adherence assays to human epithelial cells for selected classic and sporadic non-Ec-Sp revealed that the presence of a integrative conjugative element (ICE) results in increased adherence to human epithelial cells (P = 0.005). In contrast, sporadic non-Ec-Sp lacking the ICE had greater growth in vitro possibly resulting in improved fitness. In conclusion, non-Ec-Sp isolates from the classic lineage have evolved separately. They have spread globally, are well adapted to nasopharyngeal carriage and are able to coexist with Ec-Sp. Due to continued use of PCV, non-Ec-Sp may become more prevalent.
Collapse
Affiliation(s)
- Markus Hilty
- Institute for Infectious Diseases, University of Bern, Switzerland Department of Infectious Diseases, Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - Daniel Wüthrich
- Interfaculty Bioinformatics Unit, University of Bern, Switzerland Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Hansjürg Engel
- Institute for Infectious Diseases, University of Bern, Switzerland
| | - Samuel Campbell
- Institute for Infectious Diseases, University of Bern, Switzerland
| | - Raquel Sá-Leão
- Instituto de Tecnologia Química e Biológica, University of Lisbon, Portugal
| | - Hermínia de Lencastre
- Instituto de Tecnologia Química e Biológica, University of Lisbon, Portugal Laboratory of Microbiology and Infectious Diseases, The Rockefeller University
| | - Peter Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Ewa Sadowy
- National Medicines Institute, Warsaw, Poland
| | - Paul Turner
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Claire Chewapreecha
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Mathew Diggle
- Clinical Microbiology Department, Queens Medical Centre, Nottingham, United Kingdom
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, University of Basel, Switzerland
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Georgia, Atlanta
| | - Özgen Köseoğlu Eser
- Department of Microbiology, Medical Faculty, Hacettepe University, Ankara, Turkey
| | - Donald E Low
- Mt Sinai Hospital & Public Health Laboratories, Toronto, Ontario, Canada
| | | | - Andrea Endimiani
- Institute for Infectious Diseases, University of Bern, Switzerland
| | - Marianne Küffer
- Institute for Infectious Diseases, University of Bern, Switzerland
| | | | | | - Johann Weber
- Centre for Integrative Genomics, University of Lausanne, Switzerland
| | - Rémy Bruggmann
- Interfaculty Bioinformatics Unit, University of Bern, Switzerland Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - William P Hanage
- Department of Epidemiology, Center for Communicable Disease Dynamics, Harvard School of Public Health
| | | | - Lucy J Hathaway
- Institute for Infectious Diseases, University of Bern, Switzerland
| | - Kathrin Mühlemann
- Institute for Infectious Diseases, University of Bern, Switzerland Department of Infectious Diseases, Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - Stephen D Bentley
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom Department of Medicine, Addenbrookes Hospital, University of Cambridge, United Kingdom
| |
Collapse
|
13
|
Murrah KA, Pang B, Richardson S, Perez A, Reimche J, King L, Wren J, Swords WE. Nonencapsulated Streptococcus pneumoniae causes otitis media during single-species infection and during polymicrobial infection with nontypeable Haemophilus influenzae. Pathog Dis 2014; 73:ftu011. [PMID: 26014114 DOI: 10.1093/femspd/ftu011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2014] [Indexed: 12/29/2022] Open
Abstract
Streptococcus pneumoniae strains lacking capsular polysaccharide have been increasingly reported in carriage and disease contexts. Since most cases of otitis media involve more than one bacterial species, we aimed to determine the capacity of a nonencapsulated S. pneumoniae clinical isolate to induce disease in the context of a single-species infection and as a polymicrobial infection with nontypeable Haemophilus influenzae. Using the chinchilla model of otitis media, we found that nonencapsulated S. pneumoniae colonizes the nasopharynx following intranasal inoculation, but does not readily ascend into the middle ear. However, when we inoculated nonencapsulated S. pneumoniae directly into the middle ear, the bacteria persisted for two weeks post-inoculation and induced symptoms consistent with chronic otitis media. During coinfection with nontypeable H. influenzae, both species persisted for one week and induced polymicrobial otitis media. We also observed that nontypeable H. influenzae conferred passive protection from killing by amoxicillin upon S. pneumoniae from within polymicrobial biofilms in vitro. Therefore, based on these results, we conclude that nonencapsulated pneumococci are a potential causative agent of chronic/recurrent otitis media, and can also cause mutualistic infection with other opportunists, which could complicate treatment outcomes.
Collapse
Affiliation(s)
- Kyle A Murrah
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - Bing Pang
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - Stephen Richardson
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - Antonia Perez
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - Jennifer Reimche
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - Lauren King
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - John Wren
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| | - W Edward Swords
- Department of Microbiology and Immunology, Wake Forest School of Medicine, 2E-034 Wake Forest Biotech Place, 575 North Patterson Avenue, Winston-Salem, NC 27101, USA
| |
Collapse
|
14
|
Hathaway LJ, Bättig P, Reber S, Rotzetter JU, Aebi S, Hauser C, Heller M, Kadioglu A, Mühlemann K. Streptococcus pneumoniae detects and responds to foreign bacterial peptide fragments in its environment. Open Biol 2014; 4:130224. [PMID: 24718598 PMCID: PMC4043112 DOI: 10.1098/rsob.130224] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Streptococcus pneumoniae is an important cause of bacterial meningitis and pneumonia but usually colonizes the human nasopharynx harmlessly. As this niche is simultaneously populated by other bacterial species, we looked for a role and pathway of communication between pneumococci and other species. This paper shows that two proteins of non-encapsulated S. pneumoniae, AliB-like ORF 1 and ORF 2, bind specifically to peptides matching other species resulting in changes in the pneumococci. AliB-like ORF 1 binds specifically peptide SETTFGRDFN, matching 50S ribosomal subunit protein L4 of Enterobacteriaceae, and facilitates upregulation of competence for genetic transformation. AliB-like ORF 2 binds specifically peptides containing sequence FPPQS, matching proteins of Prevotella species common in healthy human nasopharyngeal microbiota. We found that AliB-like ORF 2 mediates the early phase of nasopharyngeal colonization in vivo. The ability of S. pneumoniae to bind and respond to peptides of other bacterial species occupying the same host niche may play a key role in adaptation to its environment and in interspecies communication. These findings reveal a completely new concept of pneumococcal interspecies communication which may have implications for communication between other bacterial species and for future interventional therapeutics.
Collapse
Affiliation(s)
- Lucy J Hathaway
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Devi U, Ayyagari A, Devi KR, Narain K, Patgiri DK, Sharma A, Mahanta J. Serotype distribution & sensitivity pattern of nasopharyngeal colonizing Streptococcus pneumoniae among rural children of eastern India. Indian J Med Res 2012; 136:495-8. [PMID: 23041746 PMCID: PMC3510899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Utpala Devi
- Regional Medical Research Centre (ICMR), Dibrugarh, India
| | - Archana Ayyagari
- Department of Microbiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India
| | | | - Kanwar Narain
- Regional Medical Research Centre (ICMR), Dibrugarh, India
| | | | - Arunima Sharma
- Regional Medical Research Centre (ICMR), Dibrugarh, India
| | - Jagadish Mahanta
- Regional Medical Research Centre (ICMR), Dibrugarh, India,For correspondence: Dr Jagadish Mahanta, Director, Regional Medical Research Centre, N.E. Region (ICMR), Post Box 105, Dibrugarh 786 001, Assam, India e-mail:
| |
Collapse
|
16
|
Scott JR, Hinds J, Gould KA, Millar EV, Reid R, Santosham M, O'Brien KL, Hanage WP. Nontypeable pneumococcal isolates among navajo and white mountain apache communities: are these really a cause of invasive disease? J Infect Dis 2012; 206:73-80. [PMID: 22536000 PMCID: PMC3415932 DOI: 10.1093/infdis/jis307] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 12/16/2012] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Pneumococci could evade pneumococcal conjugate vaccines (PCV) by modifying, mutating, or deleting vaccine-serotype capsule genes or by downregulating capsule production. We sought to assess whether pneumococci that are nontypeable (NT) by the Quellung reaction truly lack capsule genes or are failing to produce capsule in vitro. METHODS We applied multilocus sequence typing and a microarray for detection of pneumococcal polysaccharide capsule biosynthesis genes to NT carriage (children aged <5 years; years 1997-2000, 2006-2008) and NT invasive disease (IPD) (all ages; years 1994-2007) isolates from Native American communities. RESULTS Twenty-seven of 28 (96.4%) NT IPD isolates had sequence types (STs) typically found among typeable IPD isolates and contained whole or fragments of capsule genes that matched known serotypes; 1 NT-IPD isolate had a profile resembling NT carriage isolates. Forty-nine of 76 (64.5%) NT carriage isolates had STs that typically lack capsule genes and were similar to NT carriage isolates found globally. CONCLUSIONS This is the first documentation of IPD from an NT strain confirmed to lack all known capsule genes. Most NT IPD isolates have or had the capacity to produce capsule, whereas a majority of NT carriage isolates lack this capacity. We found no evidence of pneumococcal adaptation to PCV7 via downregulation or deletion of vaccine-serotype capsule genes.
Collapse
Affiliation(s)
- Jennifer R. Scott
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jason Hinds
- Bacterial Microarray Group, Division of Clinical Sciences, St George's, University of London
| | - Katherine A. Gould
- Bacterial Microarray Group, Division of Clinical Sciences, St George's, University of London
| | - Eugene V. Millar
- Infectious Disease Clinical Research Program, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Raymond Reid
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mathuram Santosham
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Katherine L. O'Brien
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William P. Hanage
- Department of Infectious Disease Epidemiology, Imperial College, London, United Kingdom
| |
Collapse
|
17
|
Differentiation of Streptococcus pneumoniae from nonpneumococcal streptococci of the Streptococcus mitis group by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol 2012; 50:2863-7. [PMID: 22718935 DOI: 10.1128/jcm.00508-12] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The differentiation of species within the Streptococcus mitis group has posed a problem in the routine diagnostic microbiology laboratory for some time. It also constitutes a major weakness of recently introduced matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) fingerprinting systems. As the phylogenetic resolution of the spectral similarity measures employed by these systems is insufficient to reliably distinguish between the most closely related members of the group, the major pathogen Streptococcus pneumoniae is frequently misidentified. In this study, a comparative analysis of MALDI-TOF spectra of several species from the S. mitis group has been performed in order to identify single peaks that could be used to improve mass spectrometry-based identification of the respective species. A characteristic peak profile could be identified that unambiguously distinguished the 14 S. pneumoniae isolates studied from 33 nonpneumococcal isolates of the S. mitis group. In addition, specific peak combinations could be assigned to other members of the group. The findings of this study suggest that it is possible to distinguish different species of the S. mitis group by close analysis of their mass peak profiles.
Collapse
|
18
|
Greve T, Møller JK. Accuracy of using the lytA gene to distinguish Streptococcus pneumoniae from related species. J Med Microbiol 2012; 61:478-482. [DOI: 10.1099/jmm.0.036574-0] [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)
- Thomas Greve
- Department of Clinical Microbiology, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N, Denmark
| | - Jens Kjølseth Møller
- Department of Clinical Microbiology, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N, Denmark
| |
Collapse
|
19
|
Novel molecular method for identification of Streptococcus pneumoniae applicable to clinical microbiology and 16S rRNA sequence-based microbiome studies. J Clin Microbiol 2012; 50:1968-73. [PMID: 22442329 DOI: 10.1128/jcm.00365-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The close phylogenetic relationship of the important pathogen Streptococcus pneumoniae and several species of commensal streptococci, particularly Streptococcus mitis and Streptococcus pseudopneumoniae, and the recently demonstrated sharing of genes and phenotypic traits previously considered specific for S. pneumoniae hamper the exact identification of S. pneumoniae. Based on sequence analysis of 16S rRNA genes of a collection of 634 streptococcal strains, identified by multilocus sequence analysis, we detected a cytosine at position 203 present in all 440 strains of S. pneumoniae but replaced by an adenosine residue in all strains representing other species of mitis group streptococci. The S. pneumoniae-specific sequence signature could be demonstrated by sequence analysis or indirectly by restriction endonuclease digestion of a PCR amplicon covering the site. The S. pneumoniae-specific signature offers an inexpensive means for validation of the identity of clinical isolates and should be used as an integrated marker in the annotation procedure employed in 16S rRNA-based molecular studies of complex human microbiotas. This may avoid frequent misidentifications such as those we demonstrate to have occurred in previous reports and in reference sequence databases.
Collapse
|
20
|
Xu Q, Kaur R, Casey JR, Sabharwal V, Pelton S, Pichichero ME. Nontypeable Streptococcus pneumoniae as an otopathogen. Diagn Microbiol Infect Dis 2011; 69:200-4. [PMID: 21251566 DOI: 10.1016/j.diagmicrobio.2010.09.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 08/23/2010] [Accepted: 09/23/2010] [Indexed: 11/26/2022]
Abstract
Among 34 Streptococcus pneumoniae (Spn) sequential isolates from middle ear fluid, we found a case of a nontypeable S. pneumoniae (NT-Spn) in a child with acute otitis media (AOM). The strain was pneumolysin PCR positive and capsule gene PCR negative. Virulence of the NT-Spn was confirmed in a chinchilla model of AOM.
Collapse
Affiliation(s)
- Qingfu Xu
- Rochester General Hospital Research Institute, Rochester, NY 14621, USA
| | | | | | | | | | | |
Collapse
|
21
|
Melchiorre S, Camilli R, Pietrantoni A, Moschioni M, Berti F, Del Grosso M, Superti F, Barocchi MA, Pantosti A. Point mutations in wchA are responsible for the non-typability of two invasive Streptococcus pneumoniae isolates. MICROBIOLOGY-SGM 2011; 158:338-344. [PMID: 22034485 DOI: 10.1099/mic.0.054270-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Non-typable Streptococcus pneumoniae (NTPn) strains are typically isolated from nasopharyngeal carriage or from conjunctivitis. Since the isolation of NTPn from invasive disease is rare, we characterized the genetic basis of the non-typability of two isolates obtained in Italy from two cases of bacteraemic pneumonia. MLST revealed that both NTPn belonged to ST191, which, according to the MLST database, is associated with serotype 7F. Sequencing of the capsular locus (cps) confirmed the presence of a 7F cps in both strains and revealed the existence of distinct single point mutations in the wchA gene (a glycosyltransferase), both leading to the translation of proteins truncated at the C terminus. To verify that these mutations were responsible for the non-typability of the isolates, a functional 7F WchA was overexpressed in both NTPn. The two NTPn along with their WchA-overexpressing derivatives were analysed by transmission electron microscopy and by high-resolution magic angle spinning NMR spectroscopy. Both NTPn were devoid of a polysaccharide capsule, and WchA overexpression was sufficient to restore the assembly of a serotype 7F capsule on the surface of the two NTPn. In conclusion, we identified two new naturally occurring point mutations that lead to non-typability in the pneumococcus, and demonstrated that WchA is essential for the biosynthesis of the serotype 7F capsule.
Collapse
Affiliation(s)
| | - Romina Camilli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
| | | | | | | | - Maria Del Grosso
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Fabiana Superti
- Department of Technology and Health, Istituto Superiore di Sanità, Rome, Italy
| | | | - Annalisa Pantosti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
| |
Collapse
|
22
|
Haas W, Hesje CK, Sanfilippo CM, Morris TW. High proportion of nontypeable Streptococcus pneumoniae isolates among sporadic, nonoutbreak cases of bacterial conjunctivitis. Curr Eye Res 2011; 36:1078-85. [PMID: 21988450 DOI: 10.3109/02713683.2011.624670] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Outbreaks of bacterial conjunctivitis have been linked to nontypeable strains of Streptococcus pneumoniae that lack a capsule, a key virulence factor for invasive infections. In contrast, isolates from sporadic, nonoutbreak cases of conjunctivitis were thought to be similar to invasive or nasopharyngeal isolates with respect to their capsular serotype and antibiotic resistance profile. This hypothesis was tested for 302 strains isolated during three prospective, multicenter clinical studies of bacterial conjunctivitis. MATERIALS AND METHODS S. pneumoniae capsular serotypes were determined by agglutination assay and confirmed by the Statens Serum Institute. The presence of the cpsAB capsule genes was determined by polymerase chain reaction (PCR). Minimum inhibitory concentrations were measured for 17 antibacterial drugs by the broth microdilution method. RESULTS Only 25 (8.3%) isolates reacted with the capsule-specific antisera and only one (0.3%) of these serotypes was covered by the capsule-specific PCV7 vaccine. The remaining 277 (91.7%) isolates were nontypeable, suggesting that they did not produce a capsule. PCR analysis indicated the loss of the capsule operon in 24/25 randomly selected nontypeable strains. Resistance rates were highest for azithromycin, trimethoprim, and tetracycline, while no resistance was detected for the fluoroquinolones, linezolid, and vancomycin. Antibiotic resistance rates were generally lower than those reported for invasive isolates, although some highly resistant or multidrug-resistant isolates were identified. CONCLUSIONS The prevalence of nontypeable strains of S. pneumoniae was higher than expected, while the number of isolates responsive to the PCV7 vaccine was surprisingly low. These results highlight the need for new vaccines that can target all S. pneumoniae strains regardless of the presence or nature of a capsule. In addition, resistance to azithromycin, erythromycin, tetracycline, and trimethoprim was greater than 10%, which may be relevant when selecting empiric treatments for ocular surface infections.
Collapse
|
23
|
Serotyping of Streptococcus pneumoniae isolates from nasopharyngeal samples: use of an algorithm combining microbiologic, serologic, and sequential multiplex PCR techniques. J Clin Microbiol 2011; 49:3209-14. [PMID: 21775540 DOI: 10.1128/jcm.00610-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated nasopharyngeal carriage of Streptococcus pneumoniae (pneumococci) in nine Alaskan communities and used an algorithm combining microbiologic, serologic, and sequential multiplex PCR (MP-PCR) techniques to serotype the isolates. After microbiological identification as pneumococci, isolates (n = 1,135) were serotyped using latex agglutination and Quellung tests (LA/Q) as well as a series of six sequential MP-PCR assays. Results from the two methods agreed for 94% (1,064/1,135) of samples. Eighty-six percent (61/71) of the discordant results were resolved. Discordant results occurred because (i) the MP-PCR gel was misread (31/61 [51%]), (ii) the LA/Q agglutination was misinterpreted (13/61 [21%]), (iii) two serotypes or sets of serotypes were identified by MP-PCR and only one of the two was identified by LA/Q (9/61 [15%]), (iv) different serotypes or sets of serotypes were identified by LA/Q and MP-PCR and both were correct (7/61 [11%]), and (v) the capsular polysaccharide locus (cps) did not amplify during the initial MP-PCR but was present upon retesting (1/61 [2%]). Overall, isolation of pneumococci followed by MP-PCR quickly and accurately identified pneumococcal serotypes in >97% of samples and made available isolates for additional tests such as antimicrobial susceptibility. Misinterpretation of the MP-PCR gel was identified as the main source of discordance. Increasing the number of MP-PCRs from six to seven and reducing the number of serotypes in each reaction may reduce this error. This method may be of use to laboratories characterizing large numbers of S. pneumoniae samples, especially when antimicrobial susceptibility data are needed.
Collapse
|
24
|
Norcross EW, Tullos NA, Taylor SD, Sanders ME, Marquart ME. Assessment of Streptococcus pneumoniae capsule in conjunctivitis and keratitis in vivo neuraminidase activity increases in nonencapsulated pneumococci following conjunctival infection. Curr Eye Res 2010; 35:787-98. [PMID: 20795860 DOI: 10.3109/02713683.2010.492462] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
PURPOSE The pneumococcal capsule is required for pathogenesis in systemic infections, yet reports show most conjunctivitis outbreaks are caused by nonencapsulated pneumococci, while keratitis infections are caused by encapsulated strains. This study aims to determine the effect of capsule in pneumococcal keratitis and conjunctivitis in rabbit models of infection. METHODS A capsule-deficient isogenic mutant was created using homologous transformation. Parent and mutant strains were injected within the upper bulbar conjunctiva (conjunctivitis) or into the corneal stroma (keratitis) of New Zealand white rabbits. Clinical examinations were performed 24 and 48 hr post-infection at which time corneas or conjunctivae were removed, homogenized, and plated to determine the recovered bacterial load. Whole eyes were removed for histological examination. The neuraminidase activity was determined following in vitro and in vivo growth. RESULTS There were no significant differences in clinical scores between the eyes infected with the parent or mutant for either infection, nor was there a difference in the amount of bacteria recovered from the cornea. In the conjunctivae, however, the mutant strain was cleared by the host faster than the parent strain. Histological examination showed slightly more infiltrating polymorphonuclear leukocytes (PMN) and macrophages in the conjunctivae infected with the parent strain. The neuraminidase activity of both strains was not significantly different when the strains were grown in vitro. However, the neuraminidase activity of the parent was significantly less than that of the mutant at 3 and 12 hr post conjunctival infection. CONCLUSIONS Although more outbreaks of pneumococcal conjunctivitis are tied to nonencapsulated S. pneumoniae strains, this study showed that an encapsulated strain was capable of establishing conjunctivitis in a rabbit injection model and survive attack by the host immune system longer than its nonencapsulated isogenic mutant. Nonetheless, the nonencapsulated pneumococci had an increased neuraminidase activity level in vivo when compared to the parent strain.
Collapse
Affiliation(s)
- Erin W Norcross
- Department of Microbiology, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA
| | | | | | | | | |
Collapse
|
25
|
Differentiation of Streptococcus pneumoniae conjunctivitis outbreak isolates by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Appl Environ Microbiol 2008; 74:5891-7. [PMID: 18708515 DOI: 10.1128/aem.00791-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus [Pnc]) is a causative agent of many infectious diseases, including pneumonia, septicemia, otitis media, and conjunctivitis. There have been documented conjunctivitis outbreaks in which nontypeable (NT), nonencapsulated Pnc has been identified as the etiological agent. The use of mass spectrometry to comparatively and differentially analyze protein and peptide profiles of whole-cell microorganisms remains somewhat uncharted. In this report, we discuss a comparative proteomic analysis between NT S. pneumoniae conjunctivitis outbreak strains (cPnc) and other known typeable or NT pneumococcal and streptococcal isolates (including Pnc TIGR4 and R6, Streptococcus oralis, Streptococcus mitis, Streptococcus pseudopneumoniae, and Streptococcus pyogenes) and nonstreptococcal isolates (including Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus) as controls. cPnc cells and controls were grown to mid-log phase, harvested, and subsequently treated with a 10% trifluoroacetic acid-sinapinic acid matrix mixture. Protein and peptide fragments of the whole-cell bacterial isolate-matrix combinations ranging in size from 2 to 14 kDa were evaluated by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Additionally Random Forest analytical tools and dendrogramic representations (Genesis) suggested similarities and clustered the isolates into distinct clonal groups, respectively. Also, a peak list of protein and peptide masses was obtained and compared to a known Pnc protein mass library, in which a peptide common and unique to cPnc isolates was tentatively identified. Information gained from this study will lead to the identification and validation of proteins that are commonly and exclusively expressed in cPnc strains which could potentially be used as a biomarker in the rapid diagnosis of pneumococcal conjunctivitis.
Collapse
|
26
|
Evolution of Streptococcus pneumoniae and its close commensal relatives. PLoS One 2008; 3:e2683. [PMID: 18628950 PMCID: PMC2444020 DOI: 10.1371/journal.pone.0002683] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Accepted: 06/18/2008] [Indexed: 11/19/2022] Open
Abstract
Streptococcus pneumoniae is a member of the Mitis group of streptococci which, according to 16S rRNA-sequence based phylogenetic reconstruction, includes 12 species. While other species of this group are considered prototypes of commensal bacteria, S. pneumoniae is among the most frequent microbial killers worldwide. Population genetic analysis of 118 strains, supported by demonstration of a distinct cell wall carbohydrate structure and competence pheromone sequence signature, shows that S. pneumoniae is one of several hundred evolutionary lineages forming a cluster separate from Streptococcus oralis and Streptococcus infantis. The remaining lineages of this distinct cluster are commensals previously collectively referred to as Streptococcus mitis and each represent separate species by traditional taxonomic standard. Virulence genes including the operon for capsule polysaccharide synthesis and genes encoding IgA1 protease, pneumolysin, and autolysin were randomly distributed among S. mitis lineages. Estimates of the evolutionary age of the lineages, the identical location of remnants of virulence genes in the genomes of commensal strains, the pattern of genome reductions, and the proportion of unique genes and their origin support the model that the entire cluster of S. pneumoniae, S. pseudopneumoniae, and S. mitis lineages evolved from pneumococcus-like bacteria presumably pathogenic to the common immediate ancestor of hominoids. During their adaptation to a commensal life style, most of the lineages gradually lost the majority of genes determining virulence and became genetically distinct due to sexual isolation in their respective hosts.
Collapse
|
27
|
Accuracy of phenotypic methods for identification of Streptococcus pneumoniae isolates included in surveillance programs. J Clin Microbiol 2008; 46:2184-8. [PMID: 18495854 DOI: 10.1128/jcm.00461-08] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Similarities between Streptococcus pneumoniae and viridans group streptococci may result in misidentification of these organisms. In surveillance programs which assess antimicrobial resistance rates among respiratory tract pathogens, such identification errors could lead to overestimates of pneumococcal resistance rates. DNA probe analysis (Gen-Probe, San Diego, CA), the bile solubility test, optochin susceptibility, colony morphology, and the capsular swelling reaction with Omni serum (Staten Serum Institut, Copenhagen, Denmark) were used to characterize 1,733 organisms provisionally identified as S. pneumoniae in a 2004 to 2005 antimicrobial resistance surveillance program. These organisms were obtained in 41 U.S. medical centers. Among these, 1,647 (95%) were determined to be S. pneumoniae by DNA probe. Elimination of those isolates found not to be S. pneumoniae resulted in 1 to 2% decreases in resistance rate estimates with penicillin, erythromycin, tetracycline, and trimethoprim-sulfamethoxazole. With AccuProbe as a reference standard, the sensitivities and specificities of each phenotypic method for the identification of S. pneumoniae were, respectively, 98.8% and 82.6% for bile solubility, 99.3% and 74.4% for the capsular swelling reaction with Omni serum, and 87.9% and 59.3% for optochin susceptibility. Colony morphology was of limited value, as 391 (23.7%) isolates lacked the typical button or mucoid colony appearance of S. pneumoniae.
Collapse
|
28
|
Williamson YM, Gowrisankar R, Longo DL, Facklam R, Gipson IK, Ades EP, Carlone GM, Sampson JS. Adherence of nontypeable Streptococcus pneumoniae to human conjunctival epithelial cells. Microb Pathog 2007; 44:175-85. [PMID: 17936571 DOI: 10.1016/j.micpath.2007.08.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 08/21/2007] [Accepted: 08/31/2007] [Indexed: 11/26/2022]
Abstract
Conjunctivitis outbreaks have occurred in the US in which nontypeable (NT) Streptococcus pneumoniae (Pnc) strains have been identified as the etiologic agent; however, the pathogenesis of Pnc conjunctivitis has not been extensively evaluated. Here we assessed the adhesive and invasive properties of 13 NT US conjunctivitis outbreak strains (cPnc) using an immortalized human conjunctival epithelial cell (HCjE) line expressing high or low levels of mucin as a surrogate for in vivo ocular surface events. Studies reveal differential binding efficiencies (up to 18-fold) among cPnc strains to HCjE cells and reduced or little adherence efficiency to high mucin-expressing (HME-HCjE). Additionally, in the presence of exogenous mucin there is considerable inhibition (20% to approximately 100%) of bacterial binding to the HCjE cells. Invasion assays suggest that the cPnc are internalized in HCjE, and less in HME-HCjE cells. Microarray analysis of cPnc isolates revealed an up-regulation of Pnc neuraminidases, and treatment of HME-HCjE cells with exogenous neuraminidase resulted in a 2-13-fold enhancement in cPnc binding. The results indicate that mucin acts as a protective barrier in vitro and that neuraminidases, which can degrade mucin, may be contributing factors leading to bacterial adherence, a first step in the pathogenesis of this transmissible infection.
Collapse
Affiliation(s)
- Yulanda M Williamson
- Centers for Disease Control and Prevention, 1600 Clifton Road, NE, Building 18, B-133, MS-G5, Atlanta, GA 30333, USA
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Sá-Leão R, Simões AS, Nunes S, Sousa NG, Frazão N, de Lencastre H. Identification, prevalence and population structure of non-typable Streptococcus pneumoniae in carriage samples isolated from preschoolers attending day-care centres. MICROBIOLOGY-SGM 2006; 152:367-376. [PMID: 16436425 DOI: 10.1099/mic.0.28596-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The authors aimed to get insights into the population structure of non-(sero)typable pneumococci (NTPn), a specific group of natural atypical pneumococci whose identification is often difficult, and which has remained insufficiently studied. A total of 265 presumptive NTPn, isolated between 1997 and 2003 from the nasopharynx of children, were characterized. Strains were confirmed to be pneumococci on the basis of bile solubility, and PCR detection or Southern blotting hybridization of lytA and psaA, genes ubiquitous in this species. Multilocus sequence typing (MLST) was used to exclude two isolates that gave ambiguous results. Non-typability was confirmed by the Quellung reaction using Omniserum. A total of 213 isolates were considered to be true NTPn. The molecular analysis of the true NTPn by PFGE and MLST showed that this population was genetically diverse, although a dominant cluster, accounting for 66 % of the isolates, was identified. Antimicrobial resistance was observed in most genetic backgrounds, and multidrug resistance to penicillin, erythromycin, clindamycin, tetracycline and sulfamethoxazole-trimethoprim was associated with strains belonging to the dominant cluster. Comparison with PFGE fingerprints and sequence types of large collections of serotypable strains showed that the genetic backgrounds of all but two NTPn were different from those found in serotypable strains. In addition, we found that NTPn strains with similar genetic backgrounds to those identified in our study had been isolated from disease sources in other countries. These observations seem to indicate that NTPn have diverse genetic backgrounds and may have evolved as a distinct group of pneumococcal isolates.
Collapse
Affiliation(s)
- Raquel Sá-Leão
- Molecular Genetics Laboratory, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Rua da Quinta Grande, 6, 2780-106 Oeiras, Portugal
| | - Alexandra S Simões
- Molecular Genetics Laboratory, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Rua da Quinta Grande, 6, 2780-106 Oeiras, Portugal
| | - Sónia Nunes
- Molecular Genetics Laboratory, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Rua da Quinta Grande, 6, 2780-106 Oeiras, Portugal
| | - Natacha G Sousa
- Molecular Genetics Laboratory, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Rua da Quinta Grande, 6, 2780-106 Oeiras, Portugal
| | - Nelson Frazão
- Molecular Genetics Laboratory, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Rua da Quinta Grande, 6, 2780-106 Oeiras, Portugal
| | - Hermínia de Lencastre
- Laboratory of Microbiology, The Rockefeller University, NY, USA
- Molecular Genetics Laboratory, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Rua da Quinta Grande, 6, 2780-106 Oeiras, Portugal
| |
Collapse
|
30
|
Buznach N, Dagan R, Greenberg D. Clinical and bacterial characteristics of acute bacterial conjunctivitis in children in the antibiotic resistance era. Pediatr Infect Dis J 2005; 24:823-8. [PMID: 16148850 DOI: 10.1097/01.inf.0000178066.24569.98] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Acute conjunctivitis is the most common eye disorder in young children. Bacteria are responsible for 54-73% of all cases. The goals of the study were to identify the rates of Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis in cases of bacterial conjunctivitis in children and to define antibiotic resistance rates. METHODS During a 2-year study period, conjunctival swabs of children 2-36 months old were collected prospectively. Nontypable H. influenzae, S. pneumoniae and M. catarrhalis were defined as the study pathogens. Analyzed variables included demography, clinical presentation, bacteriologic results and susceptibility patterns. RESULTS There were 428 patients enrolled. Of all cultures, 55% (237 of 428) yielded at least 1 of the study pathogens. H. influenzae and S. pneumoniae were isolated from 29 and 20% of cultures, respectively. beta-Lactamase production was found in 29% of H. influenzae isolates, and penicillin nonsusceptibility was observed in 60% of S. pneumoniae isolates. The most common S. pneumoniae serotypes were: 19F (14%); 6A and 14 (11% each). Nontypable S. pneumoniae was found in 12%. The 7-valent pneumococcal conjugate vaccine (PCV-7) could potentially cover 44% of all isolates. Conjunctivitis-otitis syndrome was found in 32% of patients, of whom 82% of cultures yielded H. influenzae. CONCLUSIONS Antibiotic resistance rates are alarmingly high. Conjunctivitis-otitis syndrome, predominantly caused by H. influenzae, is quite common. The potential coverage of the PCV-7 in conjunctivitis is relatively lower than that reported in other pneumococcal infections. Our findings should alert physicians on the choice of appropriate antibiotic treatment, on the frequent copresence of acute otitis media and on the potential role of conjunctivitis in the spread of antibiotic-resistant pathogens.
Collapse
Affiliation(s)
- Nava Buznach
- Pediatric Infectious Disease Unit, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | |
Collapse
|
31
|
Berrón S, Fenoll A, Ortega M, Arellano N, Casal J. Analysis of the genetic structure of nontypeable pneumococcal strains isolated from conjunctiva. J Clin Microbiol 2005; 43:1694-8. [PMID: 15814987 PMCID: PMC1081313 DOI: 10.1128/jcm.43.4.1694-1698.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
More than 50% of the nontypeable (NT) pneumococcal strains received in our laboratory for reference purposes are isolated in sporadic cases of conjunctivitis. To determine the genetic structure of the population of these NT conjunctival strains, we analyzed 75 pneumococci (40 NT and 35 typeable) isolated from conjunctivas and 30 (15 NT and 15 typeable) isolated from other sources. The NT and typeable conjunctival strains grouped in separate clusters, whereas NT and typeable pneumococci isolated from other sources were similarly distributed. NT conjunctival strains belonged to two well-differentiated clonal lineages. The first, represented by three newly described sequence types, featured fully antibiotic susceptible strains and appeared to be characteristic of conjunctival tissue; the second, represented by the previously described ST344, had a pattern of multiresistance to penicillin, tetracycline, and erythromycin and shared a genetic background with some NT strains isolated from other sources.
Collapse
Affiliation(s)
- Sonsoles Berrón
- Laboratory for Pneumococci, National Centre for Microbiology--National Institute of Health Carlos III, 28220 Majadahonda (Madrid), Spain.
| | | | | | | | | |
Collapse
|
32
|
Messmer TO, Sampson JS, Stinson A, Wong B, Carlone GM, Facklam RR. Comparison of four polymerase chain reaction assays for specificity in the identification of Streptococcus pneumoniae. Diagn Microbiol Infect Dis 2004; 49:249-54. [PMID: 15313529 DOI: 10.1016/j.diagmicrobio.2004.04.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 04/23/2004] [Indexed: 11/30/2022]
Abstract
We determined the usefulness of 4 conventional polymerase chain reaction (PCR) assays, lytA, psaA, and two primer sets from the ply gene, for accuracy in the discrimination of nontypeable (NT) Streptococcus pneumoniae from closely related atypical streptococci. The study used 100 strains. We compared the PCR results with laboratory tests that included optochin (ethylhydrocupreine hydrochloride) sensitivity, bile solubility, the Quellung reaction, and AccuProbe (Gen-Probe Inc., San Diego, CA). These latter tests did not discriminate the atypical streptococci from the NT pneumococci. All PCR primer sets amplified the NT pneumococcal isolates in agreement with the other laboratory tests. However, the IA and IB ply primers were positive for 8 of the 16 atypical streptococcal isolates, and the IIA and IIB ply primers amplified all atypical isolates. The psaA primers had only one discrepant result, a positive among the atypical streptococci. The lytA primers were the most specific with 100% specificity for all strains tested.
Collapse
Affiliation(s)
- Trudy O Messmer
- Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | | | | | | | | | | |
Collapse
|
33
|
Crum NF, Barrozo CP, Chapman FA, Ryan MAK, Russell KL. An Outbreak of Conjunctivitis Due to a Novel Unencapsulated Streptococcus pneumoniae among Military Trainees. Clin Infect Dis 2004; 39:1148-54. [PMID: 15486838 DOI: 10.1086/424522] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Accepted: 05/25/2004] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Bacterial conjunctivitis usually occurs as sporadic cases; outbreaks are uncommon and usually are associated with school campuses. We report an outbreak of Streptococcus pneumoniae conjunctivitis at a military training facility. METHODS An outbreak investigation was done. Each case of conjunctivitis was evaluated with an assessment tool including demographic and clinical data. Conjunctival swabs were obtained. Pneumococci underwent standard testing, including serotyping with the Quellung reaction, capsular staining, and multilocus sequence typing. Sequence types were compared with previous reported outbreak strains by construction of dendrograms. Carriage rates of S. pneumoniae were determined among previously undiagnosed case patients with conjunctivitis, and a case-control study was performed. Control measures included education to increase hand washing, distribution of alcohol-based hand gel, and prompt treatment of patients with conjunctivitis. RESULTS During a 6-week period, 92 cases of conjunctivitis occurred among 3500 persons, with an attack rate of 1.75 cases per 100 person-months. Eighty cases (87%) were due to S. pneumoniae; 45 (49%) were confirmed, and 35 (38%) were probable. Ten percent of recruits surveyed carried the outbreak strain. Twenty-two percent self-reported symptoms consistent with conjunctivitis during the outbreak period; sharing washcloths was associated with conjunctivitis (odds ratio, 11.7; P=.03). The causative organism was resistant to azithromycin but susceptible to telithromycin. The outbreak strain was an unencapsulated S. pneumoniae that has not been previously described; it was most closely related to the sequence type causing the Dartmouth College (Hanover, NH) outbreak of conjunctivitis in 2002. CONCLUSIONS We report a conjunctivitis outbreak among military trainees caused by a novel, unencapsulated strain of S. pneumoniae.
Collapse
Affiliation(s)
- Nancy F Crum
- Clinical Investigation Department, Naval Medical Center San Diego, San Diego, CA 92134-1005, USA.
| | | | | | | | | |
Collapse
|