Pradhan Pranita, Singh Bimala
Department of Microbiology, School of Life Sciences, Sikkim University, Gangtok, 737102, Sikkim, India.
Department of Microbiology, School of Life Sciences, Sikkim University, Gangtok, 737102, Sikkim, India.
Microb Pathog. 2025 Aug 7;208:107976. doi: 10.1016/j.micpath.2025.107976.
Effective antibiotic stewardship and monitoring of antimicrobial resistance are crucial for mitigating the emergence and spread of opportunistic nosocomial pathogens, such as Pseudomonas aeruginosa. This study aimed to identify antibiotic resistance patterns, the ability to form biofilms, and the presence of virulence-associated genes in multidrug-resistant (MDR) P. aeruginosa isolates from a multi-speciality government hospital in Sikkim, India.
Forty clinical isolates of P. aeruginosa were characterised through antimicrobial susceptibility test (AST). MDR isolates were evaluated for biofilm formation and the presence of carbapenemase genes (bla, bla, bla, bla, bla, bla), quorum sensing (lasR), efflux pump (mexAB-oprM), and various virulence-associated genes (toxA, lasA, lasB, popB, aprA, pvdA, phzM, phzS, algD) using PCR.
The ecfX gene specific to P. aeruginosa was detected in all isolates, confirming their identification. Among the isolates, 37.5 % were MDR, and 7.5 % were extensively drug-resistant (XDR), with a multiple antibiotic resistance (MAR) index ranging from 0.210 to 0.894. Some MDR isolates demonstrated resistance to meropenem (MIC 15.62-125 μμg/mL), indicating carbapenem resistance. All isolates showed a MIC of ≤ 2 μg/mL to colistin. These MDR isolates formed biofilms and harboured lasR, mexAB-oprM, along with the majority of virulence-related genes (toxA, lasA, popB, phzM, and algD). However, only two carbapenemase genes were detected: bla (66.66 %) and bla (73.33 %).
This study highlights the occurrence of biofilm-forming, MDR, and carbapenem-resistant clinical isolates of P. aeruginosa. These isolates harbour several virulence-associated genes and are fully susceptible to colistin, suggesting its potential role in treating such infections. The findings emphasise the need for continued surveillance and targeted antimicrobial stewardship in hospital settings.
有效的抗生素管理和对抗菌药物耐药性的监测对于减轻机会性医院病原体（如铜绿假单胞菌）的出现和传播至关重要。本研究旨在确定印度锡金邦一家多专科医院的多重耐药铜绿假单胞菌分离株的抗生素耐药模式、形成生物膜的能力以及毒力相关基因的存在情况。
通过抗菌药物敏感性试验（AST）对40株铜绿假单胞菌临床分离株进行鉴定。使用PCR对多重耐药分离株进行生物膜形成以及碳青霉烯酶基因（bla、bla、bla、bla、bla、bla）、群体感应（lasR）、外排泵（mexAB-oprM）和各种毒力相关基因（toxA、lasA、lasB、popB、aprA、pvdA、phzM、phzS、algD）的检测。
在所有分离株中均检测到了铜绿假单胞菌特有的ecfX基因，证实了它们的身份。在分离株中，37.5%为多重耐药，7.5%为广泛耐药（XDR），多重抗生素耐药（MAR）指数范围为0.210至0.894。一些多重耐药分离株对美罗培南耐药（MIC为15.62 - 125μg/mL），表明存在碳青霉烯耐药。所有分离株对黏菌素的MIC≤2μg/mL。这些多重耐药分离株形成生物膜，并携带lasR、mexAB-oprM以及大多数毒力相关基因（toxA、lasA、popB、phzM和algD）。然而，仅检测到两种碳青霉烯酶基因：bla（66.66%）和bla（73.33%）。
本研究突出了形成生物膜、多重耐药和耐碳青霉烯的铜绿假单胞菌临床分离株的出现情况。这些分离株携带多种毒力相关基因，且对黏菌素完全敏感，表明其在治疗此类感染中的潜在作用。研究结果强调了在医院环境中持续监测和有针对性的抗生素管理的必要性。
