Background

Giardia lamblia is a common cause of diarrhoea in returning travellers. Failure of the recommended first-line treatment, metronidazole, has frequently been observed. Recommendations for treatment of metronidazole-refractory giardiasis lack clarity and evidence.

Methods

We conducted a retrospective data analysis of returned travellers with confirmed giardiasis at the Bernhard-Nocht-Clinic in Hamburg, Germany, between 2007 and 2016.

Results

We identified 339 cases of giardiasis, mostly acquired in South Asia (n = 157). 308 patients received metronidazole as first-line treatment, leading to treatment failure in 93 cases. Statistical analysis suggested by far the highest risk of metronidazole treatment failure for travellers returning from South Asia (Odds Ratio 8.73). Second-line therapy consisted of various different therapy regimens. Combination therapy as second-line treatment seemed to be more effective than monotherapy. A repeat course of metronidazole proved to be futile.

Conclusion

This study reveals a strikingly low effectiveness of metronidazole, especially in patients returning from South Asia. Second-line treatment showed inconsistency of regimens and yielded unsatisfactory results. These findings require reconsideration of treatment strategies for giardiasis. Large prospective trials are urgently needed to assess new first-line treatment options and to help implement advice for effective, agreed second-line treatment strategies. Translational projects should be created to link the understanding of resistance mechanisms with epidemiological data and clinical outcome.

中文翻译：

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国际旅行者甲硝唑难治性贾第虫病的危险因素和管理：回顾性分析

背景

贾第鞭毛虫是返回旅行者腹泻的常见原因。经常观察到推荐的一线治疗甲硝唑失败。治疗甲硝唑难治性贾第虫病的建议缺乏明确性和证据。

方法

我们对 2007 年至 2016 年在德国汉堡 Bernhard-Nocht-Clinic 确诊贾第虫病的返回旅行者进行了回顾性数据分析。

结果

我们确定了 339 例贾第虫病，大部分在南亚获得（n = 157）。308例患者接受甲硝唑一线治疗，93例治疗失败。统计分析表明，迄今为止，从南亚返回的旅行者甲硝唑治疗失败的风险最高（优势比 8.73）。二线治疗包括各种不同的治疗方案。联合治疗作为二线治疗似乎比单药治疗更有效。甲硝唑的重复疗程被证明是徒劳的。

结论

这项研究揭示了甲硝唑的有效性极低，尤其是在从南亚返回的患者中。二线治疗显示方案不一致并且产生不令人满意的结果。这些发现需要重新考虑贾第虫病的治疗策略。迫切需要大型前瞻性试验来评估新的一线治疗方案，并帮助实施有效的、商定的二线治疗策略的建议。应创建转化项目，将耐药机制的理解与流行病学数据和临床结果联系起来。