Department of Pathology and Laboratory Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA.
Department of Clinical Epidemiology and Infection Prevention, UCLA Health, Los Angeles, CA.
Am J Infect Control. 2024 Mar;52(3):337-343. doi: 10.1016/j.ajic.2023.09.013. Epub 2023 Sep 29.
Aquatic opportunistic pathogen Aeromonas hydrophila, known to persist in low-nutrient chlorinated waters, can cause life-threatening infections. Two intensive care units experienced a cluster of Aeromonas infections following outdoor temperature spikes coinciding with recurrent plumbing issues, with fatalities due to severe underlying comorbidities co-occurring with extensively-drug resistant (XDR) Aeromonas.
We investigated this cluster using whole genome sequencing to assess genetic relatedness of isolates and identify antimicrobial resistance determinants. Three A. hydrophila were isolated from patients staying in or adjacent to rooms with plumbing issues during or immediately after periods of elevated outdoor temperatures. Sinks and faucets were swabbed for culture.
All A. hydrophila clinical isolates exhibited carbapenem resistance but were not genetically related. Diverse resistance determinants corresponding to extensively-drug resistant were found, including co-occurring KPC-3 and VIM-2, OXA-232, and chromosomal CphA-like carbapenemase genes, contributing to major treatment challenges. All 3 patients were treated with multiple antibiotic regimens to overcome various carbapenemase classes and expired due to underlying comorbidities. Environmental culture yielded no Aeromonas.
While the investigation revealed no singular source of contamination, it supports a possible link between plumbing issues, elevated outdoor temperatures and incidence of nosocomial Aeromonas infections. The diversity of carbapenemase genes detected in these wastewater-derived Aeromonas warrants heightened infection prevention precautions during periods of plumbing problems especially with heat waves.
水生机会性病原体嗜水气单胞菌，已知在低营养氯化水中持续存在，可导致危及生命的感染。两个重症监护病房在户外温度飙升与反复出现的管道问题同时发生后，出现了嗜水气单胞菌感染群集，由于严重的潜在合并症和广泛耐药（XDR）嗜水气单胞菌的发生，导致了死亡。
我们使用全基因组测序来调查这一集群，以评估分离株的遗传相关性并确定抗菌药物耐药决定因素。在户外温度升高期间或之后，有三名患者住在或紧邻有管道问题的房间，从这些患者中分离出了嗜水气单胞菌。对水槽和水龙头进行了拭子培养。
所有嗜水气单胞菌临床分离株均表现出碳青霉烯类耐药性，但遗传上没有相关性。发现了多种对应广泛耐药的耐药决定因素，包括同时存在的 KPC-3 和 VIM-2、OXA-232 以及染色体 CphA 样碳青霉烯酶基因，这给治疗带来了重大挑战。所有 3 名患者都接受了多种抗生素治疗方案来克服各种碳青霉烯酶类药物，但由于潜在的合并症而死亡。环境培养未检出嗜水气单胞菌。
虽然调查没有发现单一的污染源，但它支持了管道问题、户外温度升高和医院获得性嗜水气单胞菌感染之间可能存在的联系。在这些废水衍生的嗜水气单胞菌中检测到的碳青霉烯酶基因的多样性，在管道问题期间，特别是在热浪期间，需要加强感染预防措施。
