BARZILAI A; Interscience Conference on Antimicrobial Agents and Chemotherapy.
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 1999 Sep 26-29; 39: 712 (abstract no. 529).
Chaim Sheba Med. Ctr., Tel-Hashomer, ISRAEL.
BACKGROUND: Asymptomatic carriage following antibiotic treatment occurs in up to 30% of patients with pharyngotonsillitis that is caused by group A streptococcus (GAS). Numerous theories have been proposed to explain this phenomenon, though, none could be adopted for all the cases. Recently, GAS was shown to internalize cultured epithelial cell, and was found in vivo inside cells taken from the tonsils and pharynx of carriers. It was hypothesized that persistence of GAS might be associated with streptococcal internalization.METHODS: To examine the hypothesis, we have employed an epithelial cell culture model (HEp-2) to compare the adherence, internalization, and survival capabilities of 42 GAS stains derived from patients with acute pharyngotonsillitis. Twenty-nine isolates were derived from patients with bacterial eradication following beta-lactam antibiotic therapy, and 13 were derived from patients who became carriers following treatment.RESULTS: Since the results within each group of strains were variable, the adherence and internalization data were divided into three groups according to the level of adherence/internalization. 51.7% of the 'eradication' group adhered poorly (<30%) compared to 7.7% of strains derived from carriers. In contrast, 10.3% of the 'eradication' group versus 23.1% of the 'carrier' group were found at the high (>60%) adherence category. The difference between the average percentage of adherence in the two group of strains was significant (p=0.005). 72.4% of strains in the 'eradication' group internalized poorly (<5%), while only 30.8% of the 'carrier' group were found at this category. In contrast, 13.8% of the 'eradication' group versus 46.2% of the 'carrier' group were found at the high category level of internalization (>10%). The average percentage of internalization of strains that belong to the 'carrier' group is significantly higher than that of the 'eradication' group (p=0.02). The two groups varied also in their survival capability inside HEp-2 cells. 37.9% of strains of the 'eradication' group survived 24hr within cells versus 92.3% of strains derived from carriers (p=0.007).CONCLUSION: The results support the hypothesis that the development of the carriage state might be associated, in some of the cases, with adhesion, internalization, and survival capabilities of GAS strain.
Publication Types:
Keywords:
- Anti-Bacterial Agents
- Carrier State
- Epithelial Cells
- Humans
- Monobactams
- Pharynx
- Respiratory Tract Infections
- Streptococcus
- Streptococcus pyogenes
- microbiology
- therapy
Other ID:
UI: 102246448
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