Loss of the group A Streptococcus regulator Srv decreases biofilm formation in vivo in an otitis media model of infection.
Group A Streptococcus (GAS) is a common causative agent of pharyngitis, but the role of GAS in otitis media is underappreciated. In this study, we sought to test the hypothesis that GAS colonizes the middle ear and establishes itself in localized, three-dimensional communities representative of biofilms. To test this hypothesis, the middle ears of chinchillas were infected with either a strain of GAS capable of forming biofilms in vitro (MGAS5005) or a strain deficient in biofilm formation due to the lack of the transcriptional regulator Srv (MGAS5005 Δsrv). Infection resulted in the formation of large, macroscopic structures within the middle ears of MGAS5005- and MGAS5005 Δsrv-infected animals. Plate counts, scanning electron microscopy, LIVE/DEAD staining, and Gram staining revealed a difference in the distributions of MGAS5005 versus MGAS5005 Δsrv in the infected samples. High numbers of CFU of MGAS5005 Δsrv were isolated from the middle ear effusion, and MGAS5005 Δsrv was found randomly distributed throughout the excised macroscopic structure. In contrast, MGAS5005 was found in densely packed microcolonies indicative of biofilms within the excised material from the middle ear. CFU levels of MGAS5005 from the effusion were significantly lower than that of MGAS5005 Δsrv early during the course of infection. Allelic replacement of the chromosomally encoded streptococcal cysteine protease (speB) in the MGAS5005 Δsrv background restored biofilm formation in vivo. Interestingly, our results suggest that GAS naturally forms a biofilm during otitis media but that biofilm formation is not required to establish infection following transbullar inoculation of chinchillas.
Roberts
Amity L
AL
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Connolly
Kristie L
KL
Doern
Christopher D
CD
Holder
Robert C
RC
Reid
Sean D
SD
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D002682:Chinchilla; D004195:Disease Models, Animal; D004432:Ear, Middle / Q000382:microbiology; D005098:Exotoxins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010034:Otitis Media with Effusion / Q000382:microbiology*; D013290:Streptococcal Infections / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*
D001426:Bacterial Proteins; D005098:Exotoxins; C027951:erythrogenic toxin
J Innate Immun. 2009;1(3):215-24
20375579
J Dermatol Sci. 2003 Sep;32(3):193-9
14507444
Annu Rev Microbiol. 1987;41:435-64
3318676
Microb Pathog. 2008 Sep;45(3):217-24
18588968
Pediatr Emerg Care. 2007 Nov;23(11):779-84
18007207
Infect Immun. 2007 Feb;75(2):958-65
17130253
Infect Immun. 2008 Mar;76(3):1163-9
18174338
Annu Rev Microbiol. 1995;49:711-45
8561477
J Biol Chem. 1995 Apr 28;270(17):9862-7
7730368
Expert Rev Anti Infect Ther. 2003 Dec;1(4):667-83
15482163
J Clin Microbiol. 2006 Aug;44(8):2721-7
16891483
Nat Med. 2007 Aug;13(8):981-5
17632528
J Bacteriol. 2000 May;182(10):2675-9
10781532
J Infect Dis. 1993 Oct;168(4):865-72
8397268
Mol Microbiol. 2005 Sep;57(6):1545-56
16135223
J Infect Dis. 1992 Jul;166(1):31-7
1607705
Microb Pathog. 1993 Nov;15(5):327-46
7516997
Appl Environ Microbiol. 2006 Apr;72(4):2864-75
16597993
Int J Pediatr Otorhinolaryngol. 2000 Nov 30;56(1):33-40
11074113
Int J Pediatr Otorhinolaryngol. 2006 Oct;70(10):1811-6
16904758
J Clin Microbiol. 2003 Sep;41(9):4043-8
12958223
Microbiology (Reading). 2009 Jan;155(Pt 1):46-52
19118345
Adv Dent Res. 1997 Apr;11(1):160-7
9524452
Clin Infect Dis. 2005 Jul 1;41(1):35-41
15937760
Pediatr Infect Dis J. 2000 Sep;19(9):911-6
11001126
Microbiology (Reading). 2008 Jul;154(Pt 7):1998-2007
18599828
Microbiology (Reading). 2004 May;150(Pt 5):1559-1569
15133117
Int J Pediatr Otorhinolaryngol. 2001 Jan;57(1):1-9
11165635
Infect Immun. 1998 Aug;66(8):3931-5
9673282
J Bacteriol. 2007 Mar;189(5):2030-8
17189375
Clin Microbiol Rev. 2000 Jul;13(3):470-511
10885988
FEMS Immunol Med Microbiol. 2006 Nov;48(2):283-92
16999824
Infect Immun. 1998 Feb;66(2):771-6
9453640
Mol Microbiol. 2007 May;64(4):968-83
17501921
J Clin Invest. 2001 Feb;107(4):393-9
11181637
J Infect Dis. 2009 Mar 15;199(6):786-94
19434911
Infect Immun. 2002 Dec;70(12):6646-51
12438337
Clin Microbiol Rev. 2002 Apr;15(2):167-93
11932229
Vaccine. 1999 Jan;17(2):193-200
9987154
Eur J Pediatr. 2008 May;167(5):541-8
17668240
Infect Immun. 2004 Mar;72(3):1799-803
14977990
Infect Immun. 2003 Jan;71(1):211-7
12496168
Am J Pathol. 2005 Dec;167(6):1461-72
16314461
J Infect Dis. 2000 Feb;181(2):631-8
10669348