Limits...
Streptococcus pneumoniae is desiccation tolerant and infectious upon rehydration.

Walsh RL, Camilli A - MBio (2011)

Bottom Line: Desiccation tolerance has been to shown to be essential for long-term survival on dry surfaces.Every year, there are approximately 7 million cases of pneumococcus-based otitis media in the United States alone, while pneumococcal invasive diseases are responsible for more than 1 million deaths globally.Our results suggest that desiccation tolerance is an inherent trait of this genetically variable species and that fomites may be a source of transmission.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Molecular Microbiology, Sackler School of Graduate Biomedical Science, Howard Hughes Medical Institute and Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, Massachusetts, USA.

ABSTRACT

Unlabelled: Streptococcus pneumoniae (pneumococcus) is a frequent colonizer of the nasopharynx and one of the leading causative agents of otitis media, pneumonia, and meningitis. The current literature asserts that S. pneumoniae is transmitted person to person via respiratory droplets; however, environmental surfaces (fomites) have been linked to the spread of other respiratory pathogens. Desiccation tolerance has been to shown to be essential for long-term survival on dry surfaces. This study investigated the survival and infectivity of S. pneumoniae following desiccation under ambient conditions. We recovered viable bacteria after all desiccation periods tested, ranging from 1 h to 4 weeks. Experiments conducted under nutrient limitation indicate that desiccation is a condition separate from starvation. Desiccation of an acapsular mutant and 15 different clinical isolates shows that S. pneumoniae desiccation tolerance is independent of the polysaccharide capsule and is a species-wide phenomenon, respectively. Experiments demonstrating that nondesiccated and desiccated S. pneumoniae strains colonize the nasopharynx at comparable levels, combined with their ability to survive long-term desiccation, suggest that fomites may serve as alternate sources of pneumococcal infection.

Importance: Even with the advent of multivalent capsular polysaccharide conjugate vaccines, S. pneumoniae continues to be a major cause of morbidity and mortality worldwide. Every year, there are approximately 7 million cases of pneumococcus-based otitis media in the United States alone, while pneumococcal invasive diseases are responsible for more than 1 million deaths globally. It is believed that the human upper respiratory tract is the sole niche of S. pneumoniae and, thus, that spread occurs via close contact with an infected individual. In this study, we characterized the desiccation tolerance of S. pneumoniae and found that it can survive for many weeks postdehydration and retain infectivity. Our results suggest that desiccation tolerance is an inherent trait of this genetically variable species and that fomites may be a source of transmission.

Show MeSH

Related in: MedlinePlus

Desiccation tolerance of 17 S. pneumoniae strains. Bacteria were recovered after 48 hours of desiccation. Each data point represents an independent experiment, and bars indicate the medians.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3101785&req=5

f4: Desiccation tolerance of 17 S. pneumoniae strains. Bacteria were recovered after 48 hours of desiccation. Each data point represents an independent experiment, and bars indicate the medians.

Mentions: S. pneumoniae has a highly plastic genome, with up to 10% of variation between strains (2, 33–35). Since we eliminated the capsule as the basis for desiccation tolerance, it is possible that some genetic specificity of the D39 strain enhances its ability to survive desiccation. To determine if desiccation tolerance is shared or not by other strains, we performed 48-h desiccation experiments on 17 strains representing 14 different serotypes. All 17 strains tested survived desiccation at viabilities ranging from 0.1 to 10% (Fig. 4). For three of the serotypes (6A, 6B, and 18C), we tested both opaque- and transparent-colony-phase variants and saw no correlation between phase and desiccation tolerance. As capsular polysaccharide expression differs greatly between these two phase variants and is related to virulence in a mouse model (36), this supports our previous conclusion that the capsule is not a key factor in S. pneumoniae desiccation tolerance. Additionally, our experiments indicate that the ability to withstand the stresses of desiccation is a trait shared by numerous strains of S. pneumoniae.


Streptococcus pneumoniae is desiccation tolerant and infectious upon rehydration.

Walsh RL, Camilli A - MBio (2011)

Desiccation tolerance of 17 S. pneumoniae strains. Bacteria were recovered after 48 hours of desiccation. Each data point represents an independent experiment, and bars indicate the medians.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3101785&req=5

f4: Desiccation tolerance of 17 S. pneumoniae strains. Bacteria were recovered after 48 hours of desiccation. Each data point represents an independent experiment, and bars indicate the medians.
Mentions: S. pneumoniae has a highly plastic genome, with up to 10% of variation between strains (2, 33–35). Since we eliminated the capsule as the basis for desiccation tolerance, it is possible that some genetic specificity of the D39 strain enhances its ability to survive desiccation. To determine if desiccation tolerance is shared or not by other strains, we performed 48-h desiccation experiments on 17 strains representing 14 different serotypes. All 17 strains tested survived desiccation at viabilities ranging from 0.1 to 10% (Fig. 4). For three of the serotypes (6A, 6B, and 18C), we tested both opaque- and transparent-colony-phase variants and saw no correlation between phase and desiccation tolerance. As capsular polysaccharide expression differs greatly between these two phase variants and is related to virulence in a mouse model (36), this supports our previous conclusion that the capsule is not a key factor in S. pneumoniae desiccation tolerance. Additionally, our experiments indicate that the ability to withstand the stresses of desiccation is a trait shared by numerous strains of S. pneumoniae.

Bottom Line: Desiccation tolerance has been to shown to be essential for long-term survival on dry surfaces.Every year, there are approximately 7 million cases of pneumococcus-based otitis media in the United States alone, while pneumococcal invasive diseases are responsible for more than 1 million deaths globally.Our results suggest that desiccation tolerance is an inherent trait of this genetically variable species and that fomites may be a source of transmission.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Molecular Microbiology, Sackler School of Graduate Biomedical Science, Howard Hughes Medical Institute and Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, Massachusetts, USA.

ABSTRACT

Unlabelled: Streptococcus pneumoniae (pneumococcus) is a frequent colonizer of the nasopharynx and one of the leading causative agents of otitis media, pneumonia, and meningitis. The current literature asserts that S. pneumoniae is transmitted person to person via respiratory droplets; however, environmental surfaces (fomites) have been linked to the spread of other respiratory pathogens. Desiccation tolerance has been to shown to be essential for long-term survival on dry surfaces. This study investigated the survival and infectivity of S. pneumoniae following desiccation under ambient conditions. We recovered viable bacteria after all desiccation periods tested, ranging from 1 h to 4 weeks. Experiments conducted under nutrient limitation indicate that desiccation is a condition separate from starvation. Desiccation of an acapsular mutant and 15 different clinical isolates shows that S. pneumoniae desiccation tolerance is independent of the polysaccharide capsule and is a species-wide phenomenon, respectively. Experiments demonstrating that nondesiccated and desiccated S. pneumoniae strains colonize the nasopharynx at comparable levels, combined with their ability to survive long-term desiccation, suggest that fomites may serve as alternate sources of pneumococcal infection.

Importance: Even with the advent of multivalent capsular polysaccharide conjugate vaccines, S. pneumoniae continues to be a major cause of morbidity and mortality worldwide. Every year, there are approximately 7 million cases of pneumococcus-based otitis media in the United States alone, while pneumococcal invasive diseases are responsible for more than 1 million deaths globally. It is believed that the human upper respiratory tract is the sole niche of S. pneumoniae and, thus, that spread occurs via close contact with an infected individual. In this study, we characterized the desiccation tolerance of S. pneumoniae and found that it can survive for many weeks postdehydration and retain infectivity. Our results suggest that desiccation tolerance is an inherent trait of this genetically variable species and that fomites may be a source of transmission.

Show MeSH
Related in: MedlinePlus