Limits...
Streptococcus mitis strains causing severe clinical disease in cancer patients.

Shelburne SA, Sahasrabhojane P, Saldana M, Yao H, Su X, Horstmann N, Thompson E, Flores AR - Emerging Infect. Dis. (2014)

Bottom Line: Compared with patients infected with non-S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome).Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion.Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen.

View Article: PubMed Central - PubMed

ABSTRACT
The genetically diverse viridans group streptococci (VGS) are increasingly recognized as the cause of a variety of human diseases. We used a recently developed multilocus sequence analysis scheme to define the species of 118 unique VGS strains causing bacteremia in patients with cancer; Streptococcus mitis (68 patients) and S. oralis (22 patients) were the most frequently identified strains. Compared with patients infected with non-S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome). Combined with the sequence data, whole-genome analyses showed that S. mitis strains may more precisely be considered as >2 species. Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion. Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen.

Show MeSH

Related in: MedlinePlus

A) Pitt bacteremia scores for cancer patients infected with particular VGS species, showing thatmore clinically severe disease is caused by Streptococcus mitis strains than otherviridans group streptococci (VGS) species. B) Pitt bacteremia scores for only those cancer patientswith neutropenia. p values refer to Mann-Whitney U comparison of Pitt bacteremia scores for patientsinfected with S. mitis strains versus those infected with non–S.mitis strains. infan., infantis; aust.,australis; para., parasanguinis;sang., sanguinus; angi.,anginosus; cons., constellatus;sali., salivarius; vest.,vestibularis.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4012796&req=5

Figure 2: A) Pitt bacteremia scores for cancer patients infected with particular VGS species, showing thatmore clinically severe disease is caused by Streptococcus mitis strains than otherviridans group streptococci (VGS) species. B) Pitt bacteremia scores for only those cancer patientswith neutropenia. p values refer to Mann-Whitney U comparison of Pitt bacteremia scores for patientsinfected with S. mitis strains versus those infected with non–S.mitis strains. infan., infantis; aust.,australis; para., parasanguinis;sang., sanguinus; angi.,anginosus; cons., constellatus;sali., salivarius; vest.,vestibularis.

Mentions: We next sought to determine if there was a relationship between VGS species and disease severity(as determined by Pitt bacteremia score). Organ dysfunction, such as hypotension, begins to occur atPitt bacteremia scores of >2 (21). The distribution of Pitt bacteremia score by infecting species isshown in Figure 2, panel A. Patients infected with S.mitis were significantly more likely to have a higher Pitt bacteremia score (p<0.01).One possible explanation for this observation is that S. mitis strains mainlycaused infections in patients with neutropenia who, compared with patients without neutropenia,might be more likely to have serious infections. Thus, we repeated the analysis, including onlypatients with neutropenia. Again, the Pitt bacteremia scores were significantly higher for patientsinfected with S. mitis (p<0.01; Figure 2,panel B). Of the 12 cases of VGS shock syndrome, 11 were caused by S. mitis strainsand 1 was caused by an S. constellatus strain (Anginosus group).


Streptococcus mitis strains causing severe clinical disease in cancer patients.

Shelburne SA, Sahasrabhojane P, Saldana M, Yao H, Su X, Horstmann N, Thompson E, Flores AR - Emerging Infect. Dis. (2014)

A) Pitt bacteremia scores for cancer patients infected with particular VGS species, showing thatmore clinically severe disease is caused by Streptococcus mitis strains than otherviridans group streptococci (VGS) species. B) Pitt bacteremia scores for only those cancer patientswith neutropenia. p values refer to Mann-Whitney U comparison of Pitt bacteremia scores for patientsinfected with S. mitis strains versus those infected with non–S.mitis strains. infan., infantis; aust.,australis; para., parasanguinis;sang., sanguinus; angi.,anginosus; cons., constellatus;sali., salivarius; vest.,vestibularis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4012796&req=5

Figure 2: A) Pitt bacteremia scores for cancer patients infected with particular VGS species, showing thatmore clinically severe disease is caused by Streptococcus mitis strains than otherviridans group streptococci (VGS) species. B) Pitt bacteremia scores for only those cancer patientswith neutropenia. p values refer to Mann-Whitney U comparison of Pitt bacteremia scores for patientsinfected with S. mitis strains versus those infected with non–S.mitis strains. infan., infantis; aust.,australis; para., parasanguinis;sang., sanguinus; angi.,anginosus; cons., constellatus;sali., salivarius; vest.,vestibularis.
Mentions: We next sought to determine if there was a relationship between VGS species and disease severity(as determined by Pitt bacteremia score). Organ dysfunction, such as hypotension, begins to occur atPitt bacteremia scores of >2 (21). The distribution of Pitt bacteremia score by infecting species isshown in Figure 2, panel A. Patients infected with S.mitis were significantly more likely to have a higher Pitt bacteremia score (p<0.01).One possible explanation for this observation is that S. mitis strains mainlycaused infections in patients with neutropenia who, compared with patients without neutropenia,might be more likely to have serious infections. Thus, we repeated the analysis, including onlypatients with neutropenia. Again, the Pitt bacteremia scores were significantly higher for patientsinfected with S. mitis (p<0.01; Figure 2,panel B). Of the 12 cases of VGS shock syndrome, 11 were caused by S. mitis strainsand 1 was caused by an S. constellatus strain (Anginosus group).

Bottom Line: Compared with patients infected with non-S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome).Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion.Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen.

View Article: PubMed Central - PubMed

ABSTRACT
The genetically diverse viridans group streptococci (VGS) are increasingly recognized as the cause of a variety of human diseases. We used a recently developed multilocus sequence analysis scheme to define the species of 118 unique VGS strains causing bacteremia in patients with cancer; Streptococcus mitis (68 patients) and S. oralis (22 patients) were the most frequently identified strains. Compared with patients infected with non-S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome). Combined with the sequence data, whole-genome analyses showed that S. mitis strains may more precisely be considered as >2 species. Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion. Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen.

Show MeSH
Related in: MedlinePlus