Grenon Sandra, von Specht Martha, Corso Alejandra, Pace Julio, Regueira Mabel
Servicio de Microbiología, Hospital Provincial de Pediatría de Misiones, Facultad de Ciencias Exactas Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Argentina.
Enferm Infecc Microbiol Clin. 2005 Jan;23(1):10-4. doi: 10.1157/13070402.
The aim of this study was to assess the local resistance patterns and serotypes of Streptococcus pneumoniae implicated in invasive infections in children in Hospital Provincial de Pediatría in Misiones, Argentina.
A total of 101 strains isolated from sterile sites between June 1998 and June 2001 were studied. Strains were identified according to standard methods. Resistance patterns were determined by disk diffusion and a macrodilution method according to NCCLS guidelines. Capsular typing was based on the Quellung technique.
Among the total, 62% of pneumonia cases, 70% of pneumonia with pleural effusion and meningitis, and 78% of sepsis occurred in children younger than 2 years old (74% of the total). Twelve serotypes were detected among 71 strains analyzed. Types 14 (37.1%), 5 (21.4%), 1 (10%), 6A/6B (7.1%), 9N and 19A (5.7%) and 9V (4.3%), were the most frequent. Penicillin (PEN) resistance was detected in 39% of isolates: 17.5% had intermediate levels and 21.5% high levels of resistance. None of the strains had PEN MICs of > 4 microg/ml. PEN resistance was limited to 5 serotypes, with 84% corresponding to type 14. Among the 71 strains, in 50 CTX MICs were < or = 0.5 microg/ml, in 18 the MIC was 1 mg/ml and in 3 the MIC was 2 microg/ml. None of the strains had CTX MICs of > 2 microg/ml. Twenty-two percent of strains were resistant to tetracycline, 48% to trimethoprim-sulfamethoxazole (TMS), 11% to chloramphenicol (CLO) and 6.8% to erythromycin. None of the isolates were resistant to vancomycin, ofloxacin or rifampin. The most common combined resistance patterns were PEN-TMS (20%), PEN-CTX-TMS (7%, 3 strains with a CTX MIC of 2 .g/ml) and PEN-TMS-CLO (5%).
The local drug resistance patterns and serotype distribution defined in this study allow appropriate empirical therapy to be established in our area and provide information that can be used assess vaccination strategies as a preventive tool for the control of invasive pneumococcal infections.
本研究旨在评估阿根廷米西奥内斯省省立儿科医院侵袭性感染患儿中肺炎链球菌的局部耐药模式和血清型。
对1998年6月至2001年6月间从无菌部位分离出的101株菌株进行研究。菌株按标准方法鉴定。根据美国国家临床实验室标准委员会（NCCLS）指南，采用纸片扩散法和微量稀释法测定耐药模式。荚膜分型基于荚膜肿胀技术。
总体而言，62%的肺炎病例、70%的伴有胸腔积液和脑膜炎的肺炎病例以及78%的败血症病例发生在2岁以下儿童中（占总数的74%）。在分析的71株菌株中检测到12种血清型。14型（37.1%）、5型（21.4%）、1型（10%）、6A/6B型（7.1%）、9N型和19A型（5.7%）以及9V型（4.3%）最为常见。在39%的分离株中检测到青霉素（PEN）耐药：17.5%为中度耐药，21.5%为高度耐药。没有菌株的PEN最低抑菌浓度（MIC）>4μg/ml。PEN耐药仅限于5种血清型，其中84%对应14型。在71株菌株中，50株的CTX MIC≤0.5μg/ml，18株的MIC为1mg/ml，3株的MIC为2μg/ml。没有菌株的CTX MIC>2μg/ml。22%的菌株对四环素耐药，48%对甲氧苄啶-磺胺甲恶唑（TMS）耐药，11%对氯霉素（CLO）耐药，6.8%对红霉素耐药。没有分离株对万古霉素、氧氟沙星或利福平耐药。最常见的联合耐药模式为PEN-TMS（20%）、PEN-CTX-TMS（7%，3株CTX MIC为2μg/ml）和PEN-TMS-CLO（5%）。
本研究确定的局部耐药模式和血清型分布有助于在我们地区制定适当的经验性治疗方案，并提供可用于评估疫苗接种策略作为控制侵袭性肺炎球菌感染预防工具的信息。
