Alikhani Mohammad Yousef, Shahcheraghi Fereshteh, Khodaparast Sepideh, Mozaffari Nejad Amir Sasan, Moghadam Mojgan K, Mousavi Sayed Fazlollah
Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
Microbiology Research Center & Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran.
Arab J Gastroenterol. 2016 Jun;17(2):95-101. doi: 10.1016/j.ajg.2016.03.005. Epub 2016 Jun 22.
Colitis is a common complication after treatment with antibiotics such as β-lactams, quinolones, and aminoglycosides. Recently, Klebsiella oxytoca has been implicated in this type of diarrhoea. The prevalence and characterisations of K. oxytoca isolated from patients with antibiotic-associated diarrhoea were investigated. The K. oxytoca isolates were also tested for cytotoxin production.
This study was conducted from May 2011 to Dec 2013. Faecal samples were collected from hospitalised patients receiving antibiotic treatment. Initial cultivation was performed on specific media. The clinical isolates were confirmed by polymerase chain reaction (PCR) using the specific K. oxytoca polygalacturonase (pehX) gene. The double-disc diffusion test was used to detect extended-spectrum beta-lactamase (ESBL)-producing strains. Tracking of ESBL-encoding genes was performed via PCR. The organism was cultured on Hep-2 cell lines for cytotoxin production.
Out of 331 samples collected from patients, 40 were confirmed molecularly to be clinical isolates of K. oxytoca. Fourteen (35%) ESBL-producing strains were isolated using the double-disc diffusion method. Among the molecularly confirmed K. oxytoca isolates, seven (17.5%) tested positive for the blaSHV gene, 12 (30%) for blaTEM, 10 (25%) for blaCTX-M, three (7.5%) for blaOXA, nine (22.5%) for blaCTX-M-15, and seven (17.5%) for blaTEM-1. Five (12%) isolates showed cytotoxin activity below 30%, 12 (30%) strains showed moderate cytotoxin activity between 30% and 60%, and 23 (58%) strains showed cytotoxin activity ⩾60%.
The cytotoxin-producing K. oxytoca is found to be one of the causes of antibiotic-induced colitis. Discontinuing treatment and allowing normal intestinal flora to be established or prescribing appropriate medication after antibiogram can help patients with antibiotic-induced haemorrhagic colitis in a timely manner.
结肠炎是使用β-内酰胺类、喹诺酮类和氨基糖苷类等抗生素治疗后的常见并发症。最近，产酸克雷伯菌被认为与这类腹泻有关。本研究调查了从抗生素相关性腹泻患者中分离出的产酸克雷伯菌的患病率及特征。还对分离出的产酸克雷伯菌进行了细胞毒素产生情况的检测。
本研究于2011年5月至2013年12月进行。从接受抗生素治疗的住院患者中采集粪便样本。在特定培养基上进行初步培养。使用产酸克雷伯菌特异性聚半乳糖醛酸酶（pehX）基因通过聚合酶链反应（PCR）对临床分离株进行确认。采用双纸片扩散试验检测产超广谱β-内酰胺酶（ESBL）的菌株。通过PCR对ESBL编码基因进行追踪。将该菌在Hep-2细胞系上培养以检测细胞毒素产生情况。
从患者采集的331份样本中，有40份经分子学确认是产酸克雷伯菌的临床分离株。采用双纸片扩散法分离出14株（35%）产ESBL菌株。在经分子学确认的产酸克雷伯菌分离株中，7株（17.5%）blaSHV基因检测呈阳性，12株（30%）blaTEM基因阳性，10株（25%）blaCTX-M基因阳性，3株（7.5%）blaOXA基因阳性，9株（22.5%）blaCTX-M-15基因阳性，7株（17.5%）blaTEM-1基因阳性。5株（12%）分离株的细胞毒素活性低于30%，12株（30%）菌株的细胞毒素活性中等，介于30%至60%之间，23株（58%）菌株的细胞毒素活性≥60%。
产细胞毒素的产酸克雷伯菌被发现是抗生素诱导的结肠炎的病因之一。停止治疗并让正常肠道菌群得以建立，或在进行药敏试验后开具适当药物，可及时帮助患有抗生素诱导的出血性结肠炎的患者。
