Department of Medical Microbiology, Postgraduate Institute of Medical Education & Research, Chandigarh, India.
Indian J Med Res. 2012 Aug;136(2):289-91.
AmpC beta lactamase producing Gram-negative bacteria have emerged worldwide. It is important to distinguish plasmid mediated AmpC β lactamases from chromosomally mediated enzymes for surveillance, epidemiology and hospital infection control as plasmid mediated genes can spread to other organisms. Occurrence of blaCMY-1 AmpC β-lactamase, a plasmid mediated cephamycinase was studied in 100 consecutive isolates of Escherichia coli from cases of complicated urinary tract infection (UTI). Screening for AmpC production was done by modified Hodge test, three dimensional test and AmpC disk test. All isolates showing a positive result by 2 out of 3 tests were then tested for blaCMY-1 gene by PCR. Fifty nine isolates were positive for AmpC β lactamase production, 56.6 per cent were positive by PCR. Eight out of 13 isolates which were negative by EDTA disk method were positive by PCR, whereas none of the isolates negative by 3D and modified Hodge test was positive by PCR. Among admitted patients urinary catheterisation was the major risk factor followed by obstructive uropathy, three patients developed urosepsis. High occurrence of blaCMY-1 AmpC β-lactamase warrants health care workers to endorse good hospital practices.
产 AmpC 酶的革兰氏阴性菌已在全球范围内出现。区分质粒介导的 AmpC β-内酰胺酶和染色体介导的酶对于监测、流行病学和医院感染控制非常重要，因为质粒介导的基因可以传播到其他生物体。在 100 例来自复杂尿路感染（UTI）病例的大肠杆菌连续分离株中，研究了 blaCMY-1 AmpC β-内酰胺酶，这是一种质粒介导的头孢菌素酶。通过改良的 Hodge 试验、三维试验和 AmpC 盘试验进行 AmpC 产生的筛选。通过 3 种试验中的 2 种试验呈阳性的所有分离株，然后通过 PCR 检测 blaCMY-1 基因。59 株分离株产 AmpC β-内酰胺酶，PCR 阳性率为 56.6%。13 株经 EDTA 盘法检测阴性的分离株中有 8 株 PCR 阳性，而经 3D 和改良 Hodge 试验检测阴性的分离株均未检出 blaCMY-1 基因。在住院患者中，导尿是主要的危险因素，其次是尿路梗阻，有 3 例患者发生了败血症。blaCMY-1 AmpC β-内酰胺酶的高发生率要求医务人员支持良好的医院实践。
