Leski Tomasz A, Taitt Chris R, Bangura Umaru, Stockelman Michael G, Ansumana Rashid, Cooper William H, Stenger David A, Vora Gary J
Naval Research Laboratory, Code 6910, 4555 Overlook Avenue SW, Washington, DC, 20375, USA.
Mercy Hospital Research Laboratory, Bo, Sierra Leone.
BMC Infect Dis. 2016 Apr 18;16:167. doi: 10.1186/s12879-016-1495-1.
The rising level of antimicrobial resistance among bacterial pathogens is one of the most significant public health problems globally. While the antibiotic resistance of clinically important bacteria is closely tracked in many developed countries, the types and levels of resistance and multidrug resistance (MDR) among pathogens currently circulating in most countries of sub-Saharan Africa are virtually unknown.
From December 2013 to April 2014, we collected 93 urine specimens from all outpatients showing symptoms of urinary tract infection (UTI) and 189 fomite swabs from a small hospital in Bo, Sierra Leone. Culture on chromogenic agar combined with biochemical and DNA sequence-based assays was used to detect and identify the bacterial isolates. Their antimicrobial susceptibilities were determined using a panel of 11 antibiotics or antibiotic combinations.
The 70 Enterobacteriaceae urine isolates were identified as Citrobacter freundii (n = 22), Klebsiella pneumoniae (n = 15), Enterobacter cloacae (n = 15), Escherichia coli (n = 13), Enterobacter sp./Leclercia sp. (n = 4) and Escherichia hermannii (n = 1). Antimicrobial susceptibility testing demonstrated that 85.7 % of these isolates were MDR while 64.3 % produced an extended-spectrum ß-lactamase (ESBL). The most notable observations included widespread resistance to sulphonamides (91.4 %), chloramphenicol (72.9 %), gentamycin (72.9 %), ampicillin with sulbactam (51.4 %) and ciprofloxacin (47.1 %) with C. freundii exhibiting the highest and E. coli the lowest prevalence of multidrug resistance. The environmental cultures resulted in only five Enterobacteriaceae isolates out of 189 collected with lower overall antibiotic resistance.
The surprisingly high proportion of C. freundii found in urine of patients with suspected UTI supports earlier findings of the growing role of this pathogen in UTIs in low-resource countries. The isolates of all analyzed species showed worryingly high levels of resistance to both first- and second-line antibiotics as well as a high frequency of MDR and ESBL phenotypes, which likely resulted from the lack of consistent antibiotic stewardship policies in Sierra Leone. Analysis of hospital environmental isolates however suggested that fomites in this naturally ventilated hospital were not a major reservoir for Enterobacteriaceae or antibiotic resistance determinants.
细菌病原体的抗菌耐药性水平不断上升是全球最重大的公共卫生问题之一。虽然许多发达国家密切追踪临床重要细菌的抗生素耐药性，但撒哈拉以南非洲大多数国家目前流行的病原体中的耐药类型、水平及多重耐药（MDR）情况几乎无人知晓。
2013年12月至2014年4月，我们从塞拉利昂博城一家小医院的所有表现出尿路感染（UTI）症状的门诊患者中收集了93份尿液标本，并采集了189份物体表面拭子。采用显色琼脂培养结合生化和基于DNA序列的检测方法来检测和鉴定细菌分离株。使用一组11种抗生素或抗生素组合来测定它们的抗菌敏感性。
70株肠杆菌科尿液分离株被鉴定为弗氏柠檬酸杆菌（n = 22）、肺炎克雷伯菌（n = 15）、阴沟肠杆菌（n = 15）、大肠埃希菌（n = 13）、肠杆菌属/勒克菌属（n = 4）和赫尔曼埃希菌（n = 1）。抗菌药敏试验表明，这些分离株中有85.7%为多重耐药，而64.3%产生超广谱β-内酰胺酶（ESBL）。最显著的观察结果包括对磺胺类药物（91.4%）、氯霉素（72.9%）、庆大霉素（72.9%）、氨苄西林舒巴坦（51.4%）和环丙沙星（47.1%）的广泛耐药，弗氏柠檬酸杆菌的多重耐药患病率最高，大肠埃希菌最低。环境培养在收集的189份样本中仅得到5株肠杆菌科分离株，总体抗生素耐药性较低。
在疑似UTI患者尿液中发现弗氏柠檬酸杆菌的比例高得出奇，这支持了该病原体在资源匮乏国家的UTI中作用日益增加的早期研究结果。所有分析物种的分离株对一线和二线抗生素均表现出令人担忧的高耐药水平，以及多重耐药和ESBL表型的高频率，这可能是由于塞拉利昂缺乏一致的抗生素管理政策所致。然而，对医院环境分离株的分析表明，这家自然通风医院的物体表面不是肠杆菌科或抗生素耐药决定因素的主要储存库。
