Ebruke Chinelo, Dione Michel M, Walter Brigitte, Worwui Archibald, Adegbola Richard A, Roca Anna, Antonio Martin
Vaccine and Immunity Theme, Medical Research Council Unit, Banjul, The Gambia.
Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
BMC Microbiol. 2016 Mar 12;16:38. doi: 10.1186/s12866-016-0661-3.
With the global efforts of reducing pneumococcal disease through widespread introduction of pneumococcal vaccines, concerns have emerged on the potential increase of morbidity and mortality from S. aureus disease. Little is known however, of the carriage rates of S. aureus or of its' relationship with carriage of S. pneumoniae in rural Africa, and West Africa in particular where very high rates of carriage of S. pneumoniae have been reported. This study aims to evaluate the prevalence, antibiotic susceptibility patterns and genotypes of S. aureus isolated from the nasopharynx of healthy individuals in rural Gambia before the introduction of routine use of pneumococcal conjugate vaccines in the country.
Overall prevalence of S. aureus nasopharyngeal carriage was 25.2%. All S. aureus isolates tested were susceptible to methicillin. Resistant was observed for sulphamethoxazole-trimethoprim (15%) and tetracycline (34.3%). We found 59 different sequence types (ST), 35 of which were novel. The most prevalent sequence types were ST 15 (28%) and ST 5 (4%). Eighty two percent (494/600) of study individuals were S. pneumoniae carriers with S. pneumoniae carriage rates decreasing with increasing age groups. S. aureus carriage among pneumococcal carriers was slightly lower than among non-pneumococcal carriers (24.3 versus 29.3%; p = 0.324). There were no associations of carriage between these two bacteria across the 4 age groups. However, analysis of pooled data children < 2 years and children 2 to < 5 years of age showed a statistically significant inverse association (24.1 and 50.0% for S. aureus carriage among S. pneumoniae carriers and non-carriers respectively; p = 0.015).
We report that nasopharyngeal carriage of S. aureus in rural Gambia is high in all age groups, with approximately 1 out of 4 individuals being carriers in the pre-pneumococcal vaccination era. There are indications that nasopharyngeal carriage of S.aureus could be inversely related to carriage of S. pneumoniae amongst younger children in The Gambian and that S. aureus clones in The Gambia show significant genetic diversity suggesting worldwide dissemination. Findings from this study provide a useful background for impact studies evaluating the introduction of pneumococcal vaccines or other interventions targeting the control of S. aureus infections and disease.
随着全球通过广泛接种肺炎球菌疫苗来努力减少肺炎球菌疾病，人们开始关注金黄色葡萄球菌疾病的发病率和死亡率可能会上升。然而，对于非洲农村地区，尤其是西非地区金黄色葡萄球菌的携带率及其与肺炎链球菌携带情况的关系知之甚少，据报道该地区肺炎链球菌的携带率非常高。本研究旨在评估在冈比亚农村地区常规使用肺炎球菌结合疫苗之前，从健康个体鼻咽部分离出的金黄色葡萄球菌的流行情况、抗生素敏感性模式和基因型。
金黄色葡萄球菌鼻咽部携带的总体患病率为25.2%。所有测试的金黄色葡萄球菌分离株对甲氧西林敏感。观察到对复方新诺明（15%）和四环素（34.3%）耐药。我们发现了59种不同的序列类型（ST），其中35种是新的。最常见的序列类型是ST15（28%）和ST5（4%）。82%（494/600）的研究个体是肺炎链球菌携带者，肺炎链球菌携带率随着年龄组的增加而降低。肺炎球菌携带者中金黄色葡萄球菌的携带率略低于非肺炎球菌携带者（24.3%对29.3%；p = 0.324）。在4个年龄组中，这两种细菌的携带情况没有关联。然而，对2岁以下儿童和2至<5岁儿童的汇总数据分析显示存在统计学上显著的负相关（肺炎链球菌携带者和非携带者中金黄色葡萄球菌携带率分别为24.1%和50.0%；p = 0.015）。
我们报告在冈比亚农村所有年龄组中金黄色葡萄球菌的鼻咽部携带率都很高，在肺炎球菌疫苗接种前的时代，大约每4个人中有1人是携带者。有迹象表明，在冈比亚，金黄色葡萄球菌的鼻咽部携带可能与年幼儿童中肺炎链球菌的携带呈负相关，并且冈比亚的金黄色葡萄球菌克隆显示出显著的遗传多样性，表明其在全球范围内传播。本研究的结果为评估肺炎球菌疫苗或其他针对金黄色葡萄球菌感染和疾病控制的干预措施引入的影响研究提供了有用的背景。
