Department of Internal Medicine, Hôpital Beaujon, Assistance-Publique Hôpitaux de Paris, 100 Boulevard Général Leclerc, 92100 Clichy, France.
Antimicrob Agents Chemother. 2010 Dec;54(12):5193-200. doi: 10.1128/AAC.00823-10. Epub 2010 Sep 27.
The important role of commensal flora as a natural reservoir of bacterial resistance is now well established. However, whether the behavior of each commensal flora is similar to that of other floras in terms of rates of carriage and risk factors for bacterial resistance is unknown. During a 6-month period, we prospectively investigated colonization with fluoroquinolone-resistant bacteria in the three main commensal floras from hospitalized patients at admission, targeting Escherichia coli in the fecal flora, coagulase-negative Staphylococcus (CNS) in the nasal flora, and α-hemolytic streptococci in the pharyngeal flora. Resistant strains were detected on quinolone-containing selective agar. Clinical and epidemiological data were collected. A total of 555 patients were included. Carriage rates of resistance were 8.0% in E. coli, 30.3% in CNS for ciprofloxacin, and 27.2% in streptococci for levofloxacin; 56% of the patients carried resistance in at least one flora but only 0.9% simultaneously in all floras, which is no more than random. Risk factors associated with the carriage of fluoroquinolone-resistant strains differed between fecal E. coli (i.e., colonization by multidrug-resistant bacteria) and nasal CNS (i.e., age, coming from a health care facility, and previous antibiotic treatment with a fluoroquinolone) while no risk factors were identified for pharyngeal streptococci. Despite high rates of colonization with fluoroquinolone-resistant bacteria, each commensal flora behaved independently since simultaneous carriage of resistance in the three distinct floras was uncommon, and risk factors differed. Consequences of environmental selective pressures vary in each commensal flora according to its local specificities (clinical trial NCT00520715 [http://clinicaltrials.gov/ct2/show/NCT00520715]).
定植于人体的共生菌群是细菌耐药性的天然储库，这一重要作用已得到充分证实。然而，每一种共生菌群在细菌耐药率及耐药危险因素方面的行为是否与其他菌群相似尚不清楚。在 6 个月的时间里，我们前瞻性地研究了住院患者的三种主要共生菌群（粪便菌群中的大肠埃希菌、鼻腔菌群中的凝固酶阴性葡萄球菌以及咽腔菌群中的α-溶血性链球菌）中对氟喹诺酮类耐药菌的定植情况，目标是检测粪便菌群中的大肠埃希菌、鼻腔菌群中的凝固酶阴性葡萄球菌对环丙沙星的耐药率以及咽腔菌群中的链球菌对左氧氟沙星的耐药率。耐药菌株在含喹诺酮类药物的选择性琼脂上被检出。同时收集临床和流行病学数据。共纳入 555 例患者。大肠埃希菌对环丙沙星的耐药率为 8.0%，凝固酶阴性葡萄球菌为 30.3%，链球菌为 27.2%；至少有一种菌群携带耐药的患者占 56%，但同时三种菌群均携带耐药的患者仅占 0.9%，这一比例并不超过随机水平。粪便大肠埃希菌（即多重耐药菌定植）与鼻腔凝固酶阴性葡萄球菌（即来源于医疗机构、先前使用过氟喹诺酮类药物治疗）携带氟喹诺酮耐药株的危险因素不同，而咽腔链球菌则无明确的危险因素。尽管对氟喹诺酮类耐药菌的定植率较高，但由于三种不同的共生菌群同时携带耐药的情况并不常见，且危险因素不同，因此每一种共生菌群的行为都是独立的。根据局部的特殊性，环境选择压力的后果在每种共生菌群中有所不同（临床试验 NCT00520715[http://clinicaltrials.gov/ct2/show/NCT00520715]）。
