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PLOS ONE  2012 

Lysozyme Resistance in Streptococcus suis Is Highly Variable and Multifactorial

DOI: 10.1371/journal.pone.0036281

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Background Streptococcus suis is an important infectious agent for pigs and occasionally for humans. The host innate immune system plays a key role in preventing and eliminating S. suis infections. One important constituent of the innate immune system is the protein lysozyme, which is present in a variety of body fluids and immune cells. Lysozyme acts as a peptidoglycan degrading enzyme causing bacterial lysis. Several pathogens have developed mechanisms to evade lysozyme-mediated killing. In the present study we compared the lysozyme sensitivity of various S. suis isolates and investigated the molecular basis of lysozyme resistance for this pathogen. Results The lysozyme minimal inhibitory concentrations of a wide panel of S. suis isolates varied between 0.3 to 10 mg/ml. By inactivating the oatA gene in a serotype 2 and a serotype 9 strain, we showed that OatA-mediated peptidoglycan modification partly contributes to lysozyme resistance. Furthermore, inactivation of the murMN operon provided evidence that additional peptidoglycan crosslinking is not involved in lysozyme resistance in S. suis. Besides a targeted approach, we also used an unbiased approach for identifying factors involved in lysozyme resistance. Based on whole genome comparisons of a lysozyme sensitive strain and selected lysozyme resistant derivatives, we detected several single nucleotide polymorphisms (SNPs) that were correlated with the lysozyme resistance trait. Two SNPs caused defects in protein expression of an autolysin and a capsule sugar transferase. Analysis of specific isogenic mutants, confirmed the involvement of autolysin activity and capsule structures in lysozyme resistance of S. suis. Conclusions This study shows that lysozyme resistance levels are highly variable among S. suis isolates and serotypes. Furthermore, the results show that lysozyme resistance in S. suis can involve different mechanisms including OatA-mediated peptidolycan modification, autolysin activity and capsule production.


[1]  Peetermans WE, Moffie BG, Thompson J (1989) Bacterial endocarditis caused by Streptococcus suis type 2. J Infect Dis 159: 595–596.
[2]  Bungener W, Bialek R (1989) Fatal Streptococcus suis septicemia in an abattoir worker. Eur J Clin Microbiol Infect Dis 8: 306–308.
[3]  Arends JP, Zanen HC (1988) Meningitis caused by Streptococcus suis in humans. Rev Infect Dis 10: 131–137.
[4]  Wichgers Schreur PJ, Rebel JM, Smits MA, van Putten JP, Smith HE (2009) Differential activation of the Toll-like receptor 2/6 complex by lipoproteins of Streptococcus suis serotypes 2 and 9. Vet Microbiol.
[5]  Wichgers Schreur PJ, Rebel JM, Smits MA, van Putten JP, Smith HE (2011) Lgt processing is an essential Step in Streptococcus suis Lipoprotein mediated Innate Immune Activation. PLoS ONE. In press.
[6]  Cole AM, Liao HI, Stuchlik O, Tilan J, Pohl J, et al. (2002) Cationic polypeptides are required for antibacterial activity of human airway fluid. J Immunol 169: 6985–6991.
[7]  Aine E, Morsky P (1984) Lysozyme concentration in tears–assessment of reference values in normal subjects. Acta Ophthalmol (Copenh) 62: 932–938.
[8]  Welsh IR, Spitznagel JK (1971) Distribution of lysosomal enzymes, cationic proteins, and bactericidal substances in subcellular fractions of human polymorphonuclear leukocytes. Infect Immun 4: 97–102.
[9]  Markart P, Korfhagen TR, Weaver TE, Akinbi HT (2004) Mouse lysozyme M is important in pulmonary host defense against Klebsiella pneumoniae infection. Am J Respir Crit Care Med 169: 454–458.
[10]  Cramer EM, Breton-Gorius J (1987) Ultrastructural localization of lysozyme in human neutrophils by immunogold. J Leukoc Biol 41: 242–247.
[11]  Shimada J, Moon SK, Lee HY, Takeshita T, Pan H, et al. (2008) Lysozyme M deficiency leads to an increased susceptibility to Streptococcus pneumoniae-induced otitis media. BMC Infect Dis 8: 134.
[12]  Davis KM, Akinbi HT, Standish AJ, Weiser JN (2008) Resistance to mucosal lysozyme compensates for the fitness deficit of peptidoglycan modifications by Streptococcus pneumoniae. PLoS Pathog 4: e1000241.
[13]  Vollmer W, Tomasz A (2000) The pgdA gene encodes for a peptidoglycan N-acetylglucosamine deacetylase in Streptococcus pneumoniae. J Biol Chem 275: 20496–20501.
[14]  Crisostomo MI, Vollmer W, Kharat AS, Inhulsen S, Gehre F, et al. (2006) Attenuation of penicillin resistance in a peptidoglycan O-acetyl transferase mutant of Streptococcus pneumoniae. Mol Microbiol 61: 1497–1509.
[15]  Filipe SR, Severina E, Tomasz A (2001) The role of murMN operon in penicillin resistance and antibiotic tolerance of Streptococcus pneumoniae. Microb Drug Resist 7: 303–316.
[16]  Filipe SR, Severina E, Tomasz A (2002) The murMN operon: a functional link between antibiotic resistance and antibiotic tolerance in Streptococcus pneumoniae. Proc Natl Acad Sci U S A 99: 1550–1555.
[17]  Laaberki MH, Pfeffer J, Clarke AJ, Dworkin J (2011) O-Acetylation of peptidoglycan is required for proper cell separation and S-layer anchoring in Bacillus anthracis. J Biol Chem 286: 5278–5288.
[18]  Fittipaldi N, Sekizaki T, Takamatsu D, de la Cruz Dominguez-Punaro M, Harel J, et al. (2008) Significant contribution of the pgdA gene to the virulence of Streptococcus suis. Mol Microbiol 70: 1120–1135.
[19]  Holden MT, Hauser H, Sanders M, Ngo TH, Cherevach I, et al. (2009) Rapid evolution of virulence and drug resistance in the emerging zoonotic pathogen Streptococcus suis. PLoS One 4: e6072.
[20]  Chen C, Tang J, Dong W, Wang C, Feng Y, et al. (2007) A glimpse of streptococcal toxic shock syndrome from comparative genomics of S. suis 2 Chinese isolates. PLoS One 2: e315.
[21]  Zhang A, Yang M, Hu P, Wu J, Chen B, et al. (2011) Comparative Genomic Analysis of Streptococcus suis reveals significant genomic diversity among different serotypes. BMC Genomics 12: 523.
[22]  de Greeff A, Wisselink HJ, de Bree FM, Schultsz C, Baums CG, et al. (2011) Genetic diversity of Streptococcus suis isolates as determined by comparative genome hybridization. BMC Microbiol 11: 161.
[23]  Vecht U, Wisselink HJ, van Dijk JE, Smith HE (1992) Virulence of Streptococcus suis type 2 strains in newborn germfree pigs depends on phenotype. Infect Immun 60: 550–556.
[24]  Smith HE, Damman M, van der Velde J, Wagenaar F, Wisselink HJ, et al. (1999) Identification and characterization of the cps locus of Streptococcus suis serotype 2: the capsule protects against phagocytosis and is an important virulence factor. Infect Immun 67: 1750–1756.
[25]  Bera A, Herbert S, Jakob A, Vollmer W, Gotz F (2005) Why are pathogenic staphylococci so lysozyme resistant? The peptidoglycan O-acetyltransferase OatA is the major determinant for lysozyme resistance of Staphylococcus aureus. Mol Microbiol 55: 778–787.
[26]  Herbert S, Bera A, Nerz C, Kraus D, Peschel A, et al. (2007) Molecular basis of resistance to muramidase and cationic antimicrobial peptide activity of lysozyme in staphylococci. PLoS Pathog 3: e102.
[27]  Rae CS, Geissler A, Adamson PC, Portnoy DA (2011) Mutations of the Listeria monocytogenes Peptidoglycan N-Deacetylase and O-Acetylase Result in Enhanced Lysozyme Sensitivity, Bacteriolysis, and Hyperinduction of Innate Immune Pathways. Infect Immun 79: 3596–3606.
[28]  Cottagnoud P, Tomasz A (1993) Triggering of pneumococcal autolysis by lysozyme. J Infect Dis 167: 684–690.
[29]  Bera A, Biswas R, Herbert S, Kulauzovic E, Weidenmaier C, et al. (2007) Influence of wall teichoic acid on lysozyme resistance in Staphylococcus aureus. J Bacteriol 189: 280–283.
[30]  Jung CJ, Zheng QH, Shieh YH, Lin CS, Chia JS (2009) Streptococcus mutans autolysin AtlA is a fibronectin-binding protein and contributes to bacterial survival in the bloodstream and virulence for infective endocarditis. Mol Microbiol 74: 888–902.
[31]  Hirst RA, Gosai B, Rutman A, Guerin CJ, Nicotera P, et al. (2008) Streptococcus pneumoniae deficient in pneumolysin or autolysin has reduced virulence in meningitis. J Infect Dis 197: 744–751.
[32]  Zhu H, Huang D, Zhang W, Wu Z, Lu Y, et al. (2011) The novel virulence-related gene stp of Streptococcus suis serotype 9 strain contributes to a significant reduction in mouse mortality. Microb Pathog 51: 442–453.
[33]  Sambrook J, Fritsch EF, Maniatis T (1989) Molecular cloning: a Laboratory Manual. New York: Cold Spring Harbor Cold Spring Harbor Laboratory.
[34]  Smith HE, Wisselink HJ, Vecht U, Gielkens AL, Smits MA (1995) High-efficiency transformation and gene inactivation in Streptococcus suis type 2. Microbiology 141(Pt 1): 181–188.
[35]  Wichgers Schreur PJ, Rebel JM, Smits MA, van Putten JP, Smith HE (2011) Lgt processing is an essential step in Streptococcus suis lipoprotein mediated innate immune activation. PLoS One 6: e22299.
[36]  Schreur PJ, Rebel JM, Smits MA, van Putten JP, Smith HE (2011) TroA of Streptococcus suis Is Required for Manganese Acquisition and Full Virulence. J Bacteriol 193: 5073–5080.
[37]  Takamatsu D, Osaki M, Sekizaki T (2001) Thermosensitive suicide vectors for gene replacement in Streptococcus suis. Plasmid 46: 140–148.
[38]  Perez-Martinez G, Kok J, Venema G, van Dijl JM, Smith H, et al. (1992) Protein export elements from Lactococcus lactis. Mol Gen Genet 234: 401–411.
[39]  Jacques M, Gottschalk M, Foiry B, Higgins R (1990) Ultrastructural study of surface components of Streptococcus suis. J Bacteriol 172: 2833–2838.


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