Edward Eva A, El Shehawy Marwa R, Abouelfetouh Alaa, Aboulmagd Elsayed
Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, El-Khartoom Square, Azarita, Alexandria, Egypt.
Department of Microbiology and Immunology, Faculty of Pharmacy, Alamein International University, Alamein, Egypt.
Infection. 2024 Dec;52(6):2399-2414. doi: 10.1007/s15010-024-02297-8. Epub 2024 Jun 2.
Antimicrobial resistance among Pseudomonas aeruginosa (P. aeruginosa), a leading cause of nosocomial infections worldwide, is escalating. This study investigated the prevalence of extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) among 104 P. aeruginosa clinical isolates from Alexandria Main University Hospital, Alexandria, Egypt.
Antimicrobial susceptibility testing was performed using agar dilution technique, or broth microdilution method in case of colistin. ESBL and MBL prevalence was assessed phenotypically and genotypically using polymerase chain reaction (PCR). The role of plasmids in mediating resistance to extended-spectrum β-lactams was studied via transformation technique using plasmids isolated from ceftazidime-resistant isolates.
Antimicrobial susceptibility testing revealed alarming resistance rates to carbapenems, cephalosporins, and fluoroquinolones. Using PCR as the gold standard, phenotypic methods underestimated ESBL production while overestimating MBL production. Eighty-five isolates (81.7%) possessed only ESBL encoding genes, among which 69 isolates harbored a single ESBL gene [bla (n = 67) and bla (n = 2)]. Four ESBL-genotype combinations were detected: bla + bla (n = 8), bla + bla (n = 6), bla + bla (n = 1), and bla + bla + bla (n = 1). Three isolates (2.9%) possessed only the MBL encoding gene bla. Three ESBL + MBL- genotype combinations: bla + bla, bla + bla, and bla + bla + bla were detected in 2, 1 and 1 isolate(s), respectively. Five plasmid preparations harboring bla and bla were successfully transformed into chemically competent Escherichia coli DH5α with transformation efficiencies ranging between 6.8 × 10 3 and 3.7 × 10 4 CFU/μg DNA plasmid. Selected tested transformants were ceftazidime-resistant and harbored plasmids carrying bla.
The study highlights the importance of the expeditious characterization of ESBLs and MBLs using genotypic methods among P. aeruginosa clinical isolates to hinder the development and dissemination of multidrug resistant strains.
铜绿假单胞菌是全球医院感染的主要致病菌之一，其耐药性正在不断升级。本研究调查了埃及亚历山大市亚历山大主大学医院104株铜绿假单胞菌临床分离株中广谱β-内酰胺酶（ESBLs）和金属β-内酰胺酶（MBLs）的流行情况。
采用琼脂稀释法进行药敏试验，若检测黏菌素则采用肉汤微量稀释法。采用聚合酶链反应（PCR）从表型和基因型两方面评估ESBL和MBL的流行情况。通过转化技术，利用从头孢他啶耐药菌株中分离的质粒，研究质粒在介导对广谱β-内酰胺类抗生素耐药中的作用。
药敏试验显示，对碳青霉烯类、头孢菌素类和氟喹诺酮类药物的耐药率令人担忧。以PCR作为金标准，表型方法低估了ESBL的产生，同时高估了MBL的产生。85株分离株（81.7%）仅携带ESBL编码基因，其中69株携带单个ESBL基因[bla（n = 67）和bla（n = 2）]。检测到四种ESBL基因型组合：bla + bla（n = 8）、bla + bla（n = 6）、bla + bla（n = 1）和bla + bla + bla（n = 1）。3株分离株（2.9%）仅携带MBL编码基因bla。分别在2株、1株和1株分离株中检测到三种ESBL + MBL基因型组合：bla + bla、bla + bla和bla + bla + bla。5种携带bla和bla的质粒制备物成功转化为化学感受态大肠杆菌DH5α，转化效率在6.8×10³至3.7×10⁴CFU/μg DNA质粒之间。所选测试转化子对头孢他啶耐药，并携带携带bla的质粒。
该研究强调了在铜绿假单胞菌临床分离株中使用基因型方法快速鉴定ESBLs和MBLs的重要性，以阻碍多重耐药菌株的发展和传播。
