Sinha Mahua, Srinivasa H, Macaden R
Department of Microbiology, St. John&s Medical College & Hospital (SJMCH), Bangalore 560036, India.
Indian J Med Res. 2007 Jul;126(1):63-7.
BACKGROUND & OBJECTIVES: Members of the genus Acinetobacter are an important cause of nosocomial infections and with widespread resistance to various antibiotics. Extended spectrum beta lactamase (ESBL) associated resistance among Acinetobacter species is now known. The aim of this study was to speciate clinical isolates of Acinetobacter, analyze their resistance patterns, identify the production ESBLs and compare the role of different cephalosporins in detecting ESBL production in the isolates.
One hundred and fifty clinical isolates of Acinetobacter were speciated by various phenotypic tests. Antibiotic susceptibility was determined by the standard disc diffusion method. ESBL production was detected by the double disk approximation test using clavulanate containing disk and four different cephalosporin disks. Results of the above test were confirmed using the NCCLS phenotypic confirmatory test for ESBLs on a limited number of isolates.
Most of the isolates were of respiratory origin. A. calcoaceticus A. baumannii (Acb) complex was the predominant species isolated (75%). Most isolates were resistant to the antibiotics tested including the third generation cephalosporins. Most isolates were sensitive to carbapenems and cefoperazone-sulbactam. ESBL production was detected in 28 per cent of the isolates. In the double disc approximation test, cefepime and cefotaxime could detect most of the ESBLs in Acinetobacter isolates.
INTERPRETATION & CONCLUSION: A high level of antibiotic resistance was found in Acinetobacter in our study. Acb complex was the predominant and the more resistant species. Relatively high levels (28%) of ESBL have been detected in Acinetobacter and may reflect the scenario in India. ESBL production in Acinetobacter should be promptly detected and reported as it helps in treating individual cases and also in controlling the spread of these resistant phenotypes to other individuals.
不动杆菌属成员是医院感染的重要病因，且对多种抗生素具有广泛耐药性。现已了解不动杆菌属中与超广谱β-内酰胺酶（ESBL）相关的耐药情况。本研究的目的是对不动杆菌的临床分离株进行菌种鉴定，分析其耐药模式，确定ESBL的产生情况，并比较不同头孢菌素在检测分离株中ESBL产生方面的作用。
通过多种表型试验对150株不动杆菌临床分离株进行菌种鉴定。采用标准纸片扩散法测定抗生素敏感性。使用含克拉维酸的纸片和四种不同头孢菌素纸片通过双纸片协同试验检测ESBL的产生。对有限数量的分离株采用美国国家临床实验室标准委员会（NCCLS）ESBL表型确证试验对上述试验结果进行确证。
大多数分离株来源于呼吸道。醋酸钙不动杆菌-鲍曼不动杆菌（Acb）复合体是分离出的主要菌种（75%）。大多数分离株对所检测的抗生素耐药，包括第三代头孢菌素。大多数分离株对碳青霉烯类和头孢哌酮-舒巴坦敏感。28%的分离株检测到ESBL产生。在双纸片协同试验中，头孢吡肟和头孢噻肟能检测出不动杆菌分离株中的大多数ESBL。
在我们的研究中发现不动杆菌具有较高水平的抗生素耐药性。Acb复合体是主要且耐药性更强的菌种。在不动杆菌中检测到相对较高水平（28%）的ESBL，这可能反映了印度的情况。不动杆菌中ESBL的产生应及时检测和报告，因为这有助于治疗个体病例，也有助于控制这些耐药表型向其他个体的传播。
