Frequency of beta toxin and phage Sa3 genes of Staphylococcus aureus in multiple sclerosis patients and healthy nasal carriers

Background: Asymptomatic nasal colonization of Methicillin-Resistant Staphylococcus aureus is common in Multiple Sclerosis patients. SCCmec types I to III are mainly attributed to HA-MRSA strains whereas SCCmec types IV and V have commonly been reported in CA-MRSA infections. Here, we assessed the frequency of nasal carriage of MRSA in MS patients. This study aimed to evaluate MRSA SCCmec typing in MS nasal carriage. Methods: A cross-sectional descriptive study was conducted from Feb and Jun 2017 in MS Research Center, Tehran University of Medical Sciences (TUMS), Iran. Overall, 620 nasal swabs were collected (325 from MS patients and 295 from control group). Antimicrobial susceptibility test was performed using the disk diffusion and E-test method. Presence of mecA gene was confirmed by PCR assay and multiplex PCR was performed for SCCmec typing of MRSA isolates. Results: The frequency of MRSA among the MS patients and control group was almost equal (9.2% and 10.1%, respectively). SCCmec typing detected only types III, IV and V in both groups and type IV was the most predominant type in MS patients and control group. SCCmec type III was more prevalent in control group than MS patients (40% vs. 20%). Moreover, the frequency of SCCmec type V in MS patients was significantly higher than control group (36.7% vs. 3.3%). Conclusion: Although most MRSA isolates were collected from inpatients, interestingly there is a high frequency of SCCmec types IV and V in MS group. Moreover, MRSA isolates were not resistant to more antibiotics in SCCmec type III than types IV-V.

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Impaired interleukin-12 production in multiple sclerosis patients

Multiple Sclerosis Journal ◽

10.1177/135245859900500505 ◽

1999 ◽

Vol 5 (5) ◽

pp. 327-334 ◽

Cited By ~ 8

Author(s):

C Rohowsky-Kochan ◽

D Molinaro ◽

A Choudhry ◽

M Kahn ◽

S D Cook

Keyword(s):

Multiple Sclerosis ◽

Staphylococcus Aureus ◽

T Cell ◽

Heavy Chain ◽

Immune Therapy ◽

Biologically Active ◽

Interleukin 12 ◽

Potent Inducer ◽

Multiple Sclerosis Patients

Multiple sclerosis (MS), a disease of the human central nervous system, is believed to be a T cell mediated autoimmune disorder with genetic and environmental influences. Interleukin-12 (IL-12), a proinflammatory cytokine produced primarily by antigen presenting cells is a potent inducer of interferon-g (IFN-g) and other Th1 cytokines that may play an important role in MS pathogenesis. We have investigated IL-12 production induced by the T cell independent pathway in untreated and IFN-b treated MS patients, healthy individuals and other neurological disease (OND) patients in response to the human pathogen Staphylococcus aureus. We report that peripheral blood mononuclear cells (PBMC) from untreated MS patients produce normal amounts of the biologically active IL-12 p70 heterodimer but significantly less free IL-12 p40 heavy chain than PBMC from both healthy and disease controls when challenged in vitro with Staphylococcus aureus. Both mRNA expression of the inducible IL-12 p40 chain and protein levels were found to be reduced in untreated MS patients. No decrease in the production of the IL-12 p40 was seen in MS patients on IFN-b therapy. The decreased production of IL-12 p40 heavy chain is not attributed to increased IL-10 secretion, a defect in the production of cytokines by macrophages or the number of cytokine producing cells. The factor(s) responsible for the decrease in p40 remain to be determined. Since IL-12 p40 antagonizes the biological activity of IL-12 in vitro and in vivo, identification of a defect in the `natural' antagonist of IL-12, may provide the basis for immune therapy.

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