Pragasam Agila Kumari, Veeraraghavan Balaji, Anandan Shalini, Narasiman Vignesh, Sistla Sujatha, Kapil Arti, Mathur Purva, Ray Pallab, Wattal Chand, Bhattacharya Sanjay, Deotale Vijayashri, Subramani K, Peter J V, Hariharan T D, Ramya I, Iniyan S, Walia Kamini, Ohri V C
Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India.
Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
Indian J Med Microbiol. 2018 Jul-Sep;36(3):344-351. doi: 10.4103/ijmm.IJMM_18_294.
Pseudomonas aeruginosa is one of the most common opportunistic pathogens that cause severe infections in humans. The burden of carbapenem resistance is particularly high and is on the rise. Very little information is available on the molecular mechanisms and its clonal types of carbapenem-resistant P. aeruginosa seen in Indian hospitals. This study was undertaken to monitor the β-lactamase profile and to investigate the genetic relatedness of the carbapenemase-producing (CP) P. aeruginosa collected across different hospitals from India.
A total of 507 non-duplicate, carbapenem-resistant P. aeruginosa isolated from various clinical specimens collected during 2014-2017 across seven Indian hospitals were included. Conventional multiplex polymerase chain reaction for the genes encoding beta-lactamases such as extended-spectrum beta-lactamase (ESBL) and carbapenemase were screened. A subset of isolates (n = 133) of CP P. aeruginosa were genotyped by multilocus sequence typing (MLST) scheme.
Of the total 507 isolates, 15%, 40% and 20% were positive for genes encoding ESBLs, carbapenemases and ESBLs + carbapenemases, respectively, whilst 25% were negative for the β-lactamases screened. Amongst the ESBL genes, bla is the most predominant, followed by bla and bla, whilst bla and bla were the most predominant carbapenemases seen. However, regional differences were noted in the β-lactamases profile across the study sites. Genotyping by MLST revealed 54 different sequence types (STs). The most common are ST357, ST235, ST233 and ST244. Six clonal complexes were found (CC357, CC235, CC244, CC1047, CC664 and CC308). About 24% of total STs are of novel types and these were found to emerge from the high-risk clones.
This is the first large study from India to report the baseline data on the molecular resistance mechanisms and its association with genetic relatedness of CP P. aeruginosa circulating in Indian hospitals. bla- and bla-producing P. aeruginosa is the most prevalent carbapenemase seen in India. Majority of the isolates belongs to the high-risk international clones ST235, ST357 and ST664 which is a concern.
铜绿假单胞菌是引起人类严重感染的最常见机会性病原体之一。碳青霉烯耐药负担特别高且呈上升趋势。关于印度医院中碳青霉烯耐药铜绿假单胞菌的分子机制及其克隆类型的信息非常少。本研究旨在监测β-内酰胺酶谱，并调查从印度不同医院收集的产碳青霉烯酶（CP）铜绿假单胞菌的遗传相关性。
纳入了2014年至2017年期间从印度七家医院收集的各种临床标本中分离出的507株非重复的碳青霉烯耐药铜绿假单胞菌。对编码β-内酰胺酶（如超广谱β-内酰胺酶（ESBL）和碳青霉烯酶）的基因进行常规多重聚合酶链反应筛选。通过多位点序列分型（MLST）方案对CP铜绿假单胞菌的一部分分离株（n = 133）进行基因分型。
在总共507株分离株中，分别有15%、40%和20%的分离株编码ESBLs、碳青霉烯酶和ESBLs + 碳青霉烯酶的基因呈阳性，而25%的分离株对筛选的β-内酰胺酶呈阴性。在ESBL基因中，bla是最主要的，其次是bla和bla，而bla和bla是最主要的碳青霉烯酶。然而，研究地点之间的β-内酰胺酶谱存在区域差异。通过MLST进行基因分型显示有54种不同的序列类型（STs）。最常见的是ST357、ST235、ST233和ST244。发现了六个克隆复合体（CC357、CC235、CC244、CC1047、CC664和CC308）。约24%的总STs是新型类型，并且发现它们源自高风险克隆。
这是印度第一项大型研究，报告了印度医院中循环的CP铜绿假单胞菌的分子耐药机制及其与遗传相关性的基线数据。产bla和bla的铜绿假单胞菌是印度最常见的碳青霉烯酶。大多数分离株属于高风险的国际克隆ST235、ST357和ST664，这令人担忧。
