Meningitis caused by Streptococcus suis

Abstract

Background: In most countries with full-service microbiology services, streptococcus-like organisms visualized in a gram-stained smear of cerebrospinal fluid (CSF) from patients presenting with meningitis syndrome would be assumed to be Streptococcus pneumoniae. However, in many areas of the world, predominantly in Southeast Asia, the organism may be Streptococcus suis. Although initial antimicrobial treatment is similar, additional treatment for specific co-morbidities, such as hearing loss, may be needed. This case, involving an adult male who presented with signs and symptoms of meningitis, describes the appropriate laboratory test procedures used to make the diagnosis and the subsequent patient management strategy.
Case presentation: A previously healthy 69-year old rice farmer was admitted to the hospital with a one day history of fever, headache, neck stiffness, and altered consciousness. Initial laboratory studies were consistent with meningitis but the CSF Gram stain did not reveal any organisms. Blood cultures obtained at admission grew alpha-hemolytic, optochin-resistant colonies consistent with Streptococcus suis, and the identification was confirmed by MALDI-TOF performed at another laboratory. Unusually, the isolate was penicillin resistant. The patient received 4 g/day ceftriaxone and dexamethasone (to mitigate deafness) for 10 days and was discharged to home with moderate deafness but no residual infection.
Conclusion: Diagnosis of meningitis should include both blood cultures and CSF cultures obtained before any antibiotics are administered. In some patient populations such as those in Southeast Asia or if there is history of contact with pigs or raw pork, S. suis should be considered.

Keywords

Case report / Meningitis / Streptococcus suis / Cerebrospinal fluid laboratory analysis

CONFLICTS OF INTEREST DISCLOSURE

The authors declare that they have no conflicts of interest.

References

[1] Wertheim HFL, Nghia HDT, Taylor W, et al. Streptococcus suis: an emerging human pathogen. Clin Infect Dis. 2009; 48: 617-625. PMid:19191650. https://doi.org/10.1086/596763

[2] van Samkar A, Brouwer MC, Schultsz C, et al. Streptococcus suis meningitis in the Netherlands. J Infect. 2015; 71: 602-604. PMid:26165610. https://doi.org/10.1016/j.jinf.2015.07.001

[3] Huong VTL, Ha N, Huy NT, et al. Epidemiology, Clinical Manifestations, and Outcomes of Streptococcus suis Infection in Humans. Emerg Infect Dis [Internet]. 2014 [cited 2021 Apr 2]; 20: 1105-1114. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073838/

[4] Segura M, Zheng H, de Greeff A, et al. Latest developments on Streptococcus suis: an emerging zoonotic pathogen: part 1. Future Microbiol. 2014; 9: 441-444. PMid:24810343. https://doi.org/10.2217/fmb.14.14

[5] Estrada AA, Gottschalk M, Rossow S, et al. Serotype and Genotype (Multilocus Sequence Type) of Streptococcus suis Isolates from the United States Serve as Predictors of Pathotype. J Clin Microbiol. 2019; 57. PMid:31243086. https://doi.org/10.1128/JCM.00377-19

[6] Sekizaki T. Streptococcus suis: An Emerging Biothreat. Journal of Disaster Research. 2012; 7: 303-312. https://doi.org/10.20965/jdr.2012.p0303

[7] Willenburg. Human Streptococcus suis meningitis in the United States. The New England Journal of Medicine. 2006; 354. PMid:16554543. https://doi.org/10.1056/NEJMc053089

[8] Hughes JM, Wilson ME, Wertheim HFL, et al. Streptococcus suis: An Emerging Human Pathogen. Clinical Infectious Diseases [Internet]. 2009 [cited 2021 Apr 2]; 48: 617-625. PMid:19191650. https://doi.org/10.1086/596763

[9] Lee GT, Chiu CY, Haller BL, et al. Streptococcus suis meningitis, United States. Emerg Infect Dis. 2008; 14: 183-185. PMid:18258107. https://doi.org/10.3201/eid1401.070930

[10] Melinda P, Janet H. Challenges in Antimicrobial Susceptibility Testing and Reporting. Lab Medicine [Internet]. 2002; 33: 877-884. https://doi.org/10.1309/1V7U-RP9N-2A9Q-95X8

[11] Centers for Disease Control and Prevention. Defining the Public Health Impact of Drug-Resistant Streptococcus pneumoniae: Report of a Working Group. MMWR (RR-1) [Internet]. CDC; MMWR; 1996. Available from: https://www.cdc.gov/mmwr/PDF/rr/rr4501.pdf

[12] CLSI Performance Standards for Antimicrobial Susceptibility Testing. 29th ed.; CLSI Supplement M100. Clinical and Laboratory Standards Institute, Wayne, PA; 2019.

[13] Choi SM, Cho BH, Choi KH, et al. Menigitis caused by Streptococcus suis: case report and review of the literature. Journal of Clinical Neurology. 2012; 8: 79-82. PMid:22523518. https://doi.org/10.3988/jcn.2012.8.1.79

[14] Wertheim H, et al. Streptococcus suis, an Important Cause of Adult Bacterial Meningitis in Northern Vietnam. PlosOne [Internet]. 4. PMid:19543404. https://doi.org/10.1371/journal.pone.0005973

[15] Holmer I, Salomonsen CM, Jorsal SE, et al. Antibiotic resistance in porcine pathogenic bacteria and relation to antibiotic usage. BMC Vet Res. 2019; 15: 449. PMid:31829171. https://doi.org/10.1186/s12917-019-2162-8

[16] Lutsar I, McCracken G, Friedland I. Antibiotic Pharmacodynamics in Cerebrospinal Fluid. Clinical infectious diseases: an official publication of the Infectious Diseases Society of America. 1998; 27: 1117-1127, quiz 1128. PMid:9827256. https://doi.org/10.1086/515003

[17] Hoa NT, Chieu TTB, Nghia HDT, et al. The antimicrobial resistance patterns and associated determinants in Streptococcus suis isolated from humans in southern Vietnam, 1997-2008. BMC Infect Dis. 2011; 11: 6. PMid:21208459. https://doi.org/10.1186/1471-2334-11-6