Roles of intrinsic and acquired resistance determinants in multidrug-resistant clinical Pseudomonas aeruginosa in Bangladesh

Introduction: Pseudomonas aeruginosa is an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, P. aeruginosa, and Enterobacter spp.) pathogen one of the leading etiologies in multiple nosocomial infections. Treatment becoming increasingly difficult due to its ever-increasing antibiotic resistance trends. This study investigated clinical multidrug (MDR) (MDR-PA), their intrinsic determinants, including presence chromosomal AmpC β-lactamase (Ampicillinase), decreased expression outer membrane porin protein OprD selected acquired genes.
 Methods: Out 238 specimens, urines from urinary tract-infected patients, wound swabs, burn catheter aspirates, were collected two major hospitals Savar, Dhaka, Bangladesh. Samples inoculated with Cetrimide agar isolate presumptive aeruginosa. Bacteria identified by cultural, biochemical characterization, 16S rDNA sequencing, phylogenetic analysis. Virulence-associated genes namely, toxA, lasB, plcH, polymerase chain reaction (PCR). Antibiotic susceptibilities isolates against ten antibiotics belonging seven groups disc-diffusion method followed a minimum inhibitory concentration (MIC) assay. Phenotypic Metallo-β-lactamases (MBLs) production was checked double disc synergistic test selectively among imipenem-resistant isolates. Acquisition β-lactam trait examined PCR detection bla-genes variants. Mutational loss analyzed investigate determinants. overexpression assayed identification gene PCR. The level assessed real-time quantitative (RT-qPCR).
 Results: Fifty-three identified, overall isolation 22.3% (53/238), where urine remains most prevalent source. Virulence plcH 92.4%, 96.2%, 94.3%. highest phenotypic antimicrobial observed ampicillin ceftriaxone (100%), cefotaxime (96%), tetracycline (89%), azithromycin (72%), imipenem (31%), ciprofloxacin (29%), levofloxacin gentamycin (27%) ceftazidime (14%). antibiogram pattern revealed 85% as multidrug-resistant, while 12% considered extensively drug-resistant (XDR)-P. carriage blaTEM, blaSHV, blaOXA detected 4%, 2%, 2% cephalosporin-resistant isolates, respectively. Double 87% expressing MBL-mediated phenomenon. All ceftazidime-resistant showed overproduction enzyme, indicating AmpC-mediated resistance. phenotypically multidrug-resistant RT-qPCR analysis reduced at various levels isolates.
 Conclusions: depicts high prevalence MDR-PA specimens determinants play roles emerging MDR-PA.
 Bangladesh Journal Medical Science Vol. 22 No. 03 July’23 Page : 489-507