Fernandez Jorge, Fica Alberto, Ebensperger German, Calfullan Hector, Prat Soledad, Fernandez Alda, Alexandre Marcela, Heitmann Ingrid
SubDepartamento de Microbiología y Unidad de Desarrollo, Instituto de Salud Pública, Santiago, Chile.
J Clin Microbiol. 2003 Apr;41(4):1617-22. doi: 10.1128/JCM.41.4.1617-1622.2003.
Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype Enteritidis subtypes were associated with epidemic changes.
1994年，智利出现了人类肠炎沙门氏菌肠炎血清型感染。肠炎沙门氏菌肠炎血清型1型噬菌体分离株在北部占主导地位，4型噬菌体分离株在中部和南部地区占主导地位。计划开展一项研究，使用最佳鉴别分型技术对这一疫情进行特征分析。研究涉及441株肠炎沙门氏菌肠炎血清型分离株，包括疫情前的临床样本（n = 74；1975年至1993年）以及疫情期间的样本（n = 199）、食品样本（n = 72）、家禽样本（n = 57）和一些拉丁美洲样本（n = 39）。基于疫情前分离株的样本选择最佳方法，分析通过噬菌体分型、随机扩增多态性DNA和脉冲场凝胶电泳（PFGE）分析获得的鉴别力（DP）。最高的DP与BlnI PFGE-噬菌体分型分析相关（0.993）。在疫情期间之前共鉴定出38种BlnI模式（B模式），自1994年以来鉴定出19种，两个时期共有4种。通过系统发育分析鉴定出两个主要聚类，主要的B模式聚类在同一分支。综合分析显示，特定的B模式-噬菌体类型组合（亚型）在1994年之前消失，自1988年以来观察到与肠炎沙门氏菌肠炎血清型4型相关的不同基因型，并且在1994年肠炎沙门氏菌肠炎血清型扩张之前菌株多样性增加。主要的B3-4型噬菌体亚型与中部和南部地区相关，B38-1型噬菌体亚型与北部相关（P < 0.0001）。食品和家禽分离株与主要的肠炎沙门氏菌肠炎血清型亚型匹配，但在邻国（秘鲁和玻利维亚）鉴定出的分离株与在智利北部鉴定出的肠炎沙门氏菌肠炎血清型亚型不匹配。这项工作的结果表明，特定肠炎沙门氏菌肠炎血清型亚型的遗传多样性、替代和扩张与疫情变化相关。
