Irfan Seema, Idrees Faiza, Mehraj Vikram, Habib Faizah, Adil Salman, Hasan Rumina
Department of Pathology & Microbiology, The Aga Khan University, Karachi, Pakistan.
BMC Infect Dis. 2008 Jun 9;8:80. doi: 10.1186/1471-2334-8-80.
This study was conducted to evaluate drug resistance amongst bacteremic isolates of febrile neutropenic patients with particular emphasis on emergence of carbapenem resistant Gram negative bacteria and vancomycin resistant Enterococcus species.
A descriptive study was performed by reviewing the blood culture reports from febrile neutropenic patients during the two study periods i.e., 1999-00 and 2001-06. Blood cultures were performed using BACTEC 9240 automated system. Isolates were identified and antibiotic sensitivities were done using standard microbiological procedures.
Seven twenty six febrile neutropenic patients were admitted during the study period. A total of 5840 blood cultures were received, off these 1048 (18%) were culture positive. Amongst these, 557 (53%) grew Gram positive bacteria, 442 (42%) grew Gram negative bacteria, 43 (4%) fungi and 6 (1%) anaerobes. Sixty (5.7%) out of 1048 positive blood cultures were polymicrobial. In the Gram negative bacteria, Enterobacteriaceae was the predominant group; E. coli was the most frequently isolated organism in both study periods. Amongst non- Enterobacteriaceae group, Pseudomonas aeruginosa was the commonest organism isolated during first study period followed by Acinetobacter spp. However, during the second period Acinetobacter species was the most frequent pathogen. Enterobacteriaceae group showed higher statistically significant resistance in the second study period against ceftriaxone, quinolone and piperacillin/tazobactam, whilst no resistance observed against imipenem/meropenem. The susceptibility pattern of Acinetobacter species shifted from sensitive to highly resistant one with significant p values against ceftriaxone, quinolone, piperacillin/tazobactam and imipenem/meropenem. Amongst Gram positive bacteria, MRSA isolation rate remained static, vancomycin resistant Enterococcus species emerged in second study period while no Staphylococcus species resistant to vancomycin was noted.
This rising trend of highly resistant organisms stresses the increasing importance of continuous surveillance system and stewardship of antibiotics as strategies in the overall management of patients with febrile neutropenia.
本研究旨在评估发热性中性粒细胞减少患者血行感染分离株的耐药性，特别关注耐碳青霉烯革兰阴性菌和耐万古霉素肠球菌的出现情况。
通过回顾1999 - 00年和2001 - 06年这两个研究期间发热性中性粒细胞减少患者的血培养报告进行描述性研究。使用BACTEC 9240自动化系统进行血培养。采用标准微生物学程序鉴定分离株并进行药敏试验。
研究期间共收治726例发热性中性粒细胞减少患者。共收到5840份血培养样本，其中1048份（18%）培养阳性。其中，557份（53%）培养出革兰阳性菌，442份（42%）培养出革兰阴性菌，43份（4%）培养出真菌，6份（1%）培养出厌氧菌。1048份阳性血培养中有60份（5.7%）为混合菌感染。在革兰阴性菌中，肠杆菌科是主要菌群；大肠杆菌是两个研究期间最常分离出的菌种。在非肠杆菌科菌群中，铜绿假单胞菌是第一个研究期间最常分离出的菌种，其次是不动杆菌属。然而，在第二个研究期间，不动杆菌属是最常见的病原体。肠杆菌科菌群在第二个研究期间对头孢曲松、喹诺酮和哌拉西林/他唑巴坦的耐药性在统计学上有显著升高，而对亚胺培南/美罗培南未观察到耐药性。不动杆菌属的药敏模式从敏感转变为高度耐药，对头孢曲松、喹诺酮、哌拉西林/他唑巴坦和亚胺培南/美罗培南的p值有显著变化。在革兰阳性菌中，耐甲氧西林金黄色葡萄球菌的分离率保持稳定，耐万古霉素肠球菌在第二个研究期间出现，未发现对万古霉素耐药的葡萄球菌菌种。
高耐药菌的这种上升趋势凸显了持续监测系统以及抗生素管理作为发热性中性粒细胞减少患者综合管理策略的重要性日益增加。
