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Abstract：
BACKGROUND: The incidence of hospital-acquired infections in extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) has been increasing worldwide and is frequently associated with an increase in mortality and morbidity rates. The aim of this study was to characterize clinical XDR-PA isolates recovered during six months at three different hospitals in Egypt.
RESULTS: Seventy hospital-acquired clinical isolates of P. aeruginosa were classified into multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR), according to their antimicrobial resistance profile. In addition, the possession of genes associated with mobile genetic elements and genes encoding antimicrobial resistance determinants among isolates were detected using polymerase chain reaction. As a result, a significant percentage of the isolates (75.7%) were XDR, while 18.5% were MDR, however only 5.7% of the isolates were non-MDR. The phenotypic detection of carbapenemases, extended-spectrum β-lactamases (ESBLs) and metallo β-lactamase (MBL) enzymes showed that 73.6% of XDR-PA isolates were carbapenemases producers, whereas 75.5% and 88.7% of XDR-PA isolates produced ESBLs and MBL respectively. In addition, PCR screening showed that oxa gene was the most frequently detected gene of carbapenemases (91.4%), while aac(6\')-lb gene was mostly detected (84.3%) among the screened aminoglycosides-resistance genes. Furthermore, the molecular detection of the colistin resistance gene showed that 12.9% of isolates harbored mcr-1 gene. Concerning mobile genetic element markers (intI, traA, tnp513, and merA), intI was the highest detected gene as it was amplified in 67 isolates (95.7%). Finally, phylogenetic and molecular typing of the isolates via ERIC-PCR analysis revealed 10 different ERIC fingerprints.
CONCLUSIONS: The present study revealed a high prevalence of XDR-PA in hospital settings which were resistant to a variety of antibiotics due to several mechanisms. In addition, 98% of the XDR-PA clinical isolates contained at least one gene associated with movable genetic elements, which could have aided the evolution of these XDR-PA strains. To reduce spread of drug resistance, judicious use of antimicrobial agents and strict infection control measures are therefore essential.
RESULTS: Seventy hospital-acquired clinical isolates of P. aeruginosa were classified into multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR), according to their antimicrobial resistance profile. In addition, the possession of genes associated with mobile genetic elements and genes encoding antimicrobial resistance determinants among isolates were detected using polymerase chain reaction. As a result, a significant percentage of the isolates (75.7%) were XDR, while 18.5% were MDR, however only 5.7% of the isolates were non-MDR. The phenotypic detection of carbapenemases, extended-spectrum β-lactamases (ESBLs) and metallo β-lactamase (MBL) enzymes showed that 73.6% of XDR-PA isolates were carbapenemases producers, whereas 75.5% and 88.7% of XDR-PA isolates produced ESBLs and MBL respectively. In addition, PCR screening showed that oxa gene was the most frequently detected gene of carbapenemases (91.4%), while aac(6\')-lb gene was mostly detected (84.3%) among the screened aminoglycosides-resistance genes. Furthermore, the molecular detection of the colistin resistance gene showed that 12.9% of isolates harbored mcr-1 gene. Concerning mobile genetic element markers (intI, traA, tnp513, and merA), intI was the highest detected gene as it was amplified in 67 isolates (95.7%). Finally, phylogenetic and molecular typing of the isolates via ERIC-PCR analysis revealed 10 different ERIC fingerprints.
CONCLUSIONS: The present study revealed a high prevalence of XDR-PA in hospital settings which were resistant to a variety of antibiotics due to several mechanisms. In addition, 98% of the XDR-PA clinical isolates contained at least one gene associated with movable genetic elements, which could have aided the evolution of these XDR-PA strains. To reduce spread of drug resistance, judicious use of antimicrobial agents and strict infection control measures are therefore essential.
摘要：
背景：广泛耐药的铜绿假单胞菌（XDR-PA）医院获得性感染的发生率在全球范围内一直在增加，并且通常与死亡率和发病率的增加有关。这项研究的目的是表征在埃及三家不同医院六个月内恢复的临床XDR-PA分离株。
结果：70株医院获得的铜绿假单胞菌临床分离株被分类为多重耐药（MDR），广泛耐药(XDR)和泛耐药(PDR)，根据他们的抗菌素耐药性概况。此外,使用聚合酶链反应检测了分离株中与可移动遗传元件相关的基因和编码抗菌素耐药性决定因子的基因。因此,相当比例的分离株（75.7%）是XDR，18.5%是MDR，然而，只有5.7％的分离株是非MDR。碳青霉烯酶的表型检测，超广谱β-内酰胺酶(ESBLs)和金属β-内酰胺酶(MBL)表明73.6%的XDR-PA分离株是碳青霉烯酶生产者,而75.5%和88.7%的XDR-PA分离株分别产生ESBLs和MBL。此外,PCR筛选显示，oxa基因是碳青霉烯酶最常见的基因(91.4%)，而aac(6')-lb基因在筛选的氨基糖苷类耐药基因中检测到最多(84.3%)。此外，粘菌素抗性基因的分子检测显示，12.9%的分离株携带mcr-1基因。关于移动遗传元素标记(intI，traA,tnp513和MEA)，intI是检测到的最高基因，因为它在67个分离物中被扩增（95.7％）。最后,通过ERIC-PCR分析分离株的系统发育和分子分型显示了10个不同的ERIC指纹。
结论：本研究表明，医院环境中XDR-PA的患病率很高，由于多种机制，XDR-PA对多种抗生素耐药。此外,98%的XDR-PA临床分离株含有至少一个与可移动遗传元件相关的基因，这可能有助于这些XDR-PA菌株的进化。为了减少耐药性的传播，因此，明智使用抗菌药物和严格的感染控制措施至关重要。
结果：70株医院获得的铜绿假单胞菌临床分离株被分类为多重耐药（MDR），广泛耐药(XDR)和泛耐药(PDR)，根据他们的抗菌素耐药性概况。此外,使用聚合酶链反应检测了分离株中与可移动遗传元件相关的基因和编码抗菌素耐药性决定因子的基因。因此,相当比例的分离株（75.7%）是XDR，18.5%是MDR，然而，只有5.7％的分离株是非MDR。碳青霉烯酶的表型检测，超广谱β-内酰胺酶(ESBLs)和金属β-内酰胺酶(MBL)表明73.6%的XDR-PA分离株是碳青霉烯酶生产者,而75.5%和88.7%的XDR-PA分离株分别产生ESBLs和MBL。此外,PCR筛选显示，oxa基因是碳青霉烯酶最常见的基因(91.4%)，而aac(6')-lb基因在筛选的氨基糖苷类耐药基因中检测到最多(84.3%)。此外，粘菌素抗性基因的分子检测显示，12.9%的分离株携带mcr-1基因。关于移动遗传元素标记(intI，traA,tnp513和MEA)，intI是检测到的最高基因，因为它在67个分离物中被扩增（95.7％）。最后,通过ERIC-PCR分析分离株的系统发育和分子分型显示了10个不同的ERIC指纹。
结论：本研究表明，医院环境中XDR-PA的患病率很高，由于多种机制，XDR-PA对多种抗生素耐药。此外,98%的XDR-PA临床分离株含有至少一个与可移动遗传元件相关的基因，这可能有助于这些XDR-PA菌株的进化。为了减少耐药性的传播，因此，明智使用抗菌药物和严格的感染控制措施至关重要。
