Molecular characterization and antimicrobial susceptibility profile of New Delhi metallo-beta-lactamase-1-producing Escherichia coli among hospitalized patients

Metallo-beta-lactamases: mechanisms, treatment challenges, and future prospects

INTRODUCTION

Metallo-beta-lactamases (MBLs) are responsible for resistance to almost all beta-lactam antibiotics. Found predominantly in Gram-negative bacteria, they severely limit treatment options. Understanding the epidemiology, risk factors, treatment, and prevention of infections caused by MBL-producing organisms is essential to reduce their burden.

AREAS COVERED

The origins and structure of MBLs are discussed. We describe the mechanisms of action that differentiate MBLs from other beta-lactamases. We discuss the global epidemiology of MBL-producing organisms and their impact on patients' outcomes. By exposing the mechanisms of transmission of MBLs among bacterial populations, we emphasize the importance of infection prevention and control.

EXPERT OPINION

MBLs are spreading globally and challenging the majority of available antibacterial agents. Genotypic tests play an important role in the identification of MBL production. Phenotypic tests are less specific but may be used in low-resource settings, where MBLs are more predominant. Infection prevention and control are critical to reduce the spread of organisms producing MBL in healthcare systems. New combinations such as avibactam-aztreonam and new agents such as cefiderocol have shown promising results for the treatment of infections caused by MBL-producing organisms. New antibiotic and non-antibiotic agents are being developed and may improve the management of infections caused by MBL-producing organisms.

Phenotypic and genotypic characterization of multidrug-resistant isolates from patients with catheter-associated urinary tract infection in a tertiary care hospital

INTRODUCTION

Urinary tract infections (UTIs) remain as the most common infection. Catheter-associated (CA) UTI can lead to bacteremia and thereby is the leading cause of morbidity and mortality in hospitalized patients in our country.

AIMS AND OBJECTIVES

This study aims to check the prevalence of CAUTI and study the phenotypic and genotypic characters of the multidrug-resistant organisms in a tertiary care hospital, with special reference to NDM-1 and OXA-23.

MATERIALS AND METHODS

A total of 231 urine samples from patients with CA-UTI in different wards in a tertiary care hospital over a period of 3 months between June and August 2018 were collected and processed following the standard protocol. Antibiotic susceptibility tests were performed by disk-diffusion method. Modified Hodge test (MHT) was done to isolate carbapenem-resistant isolates, and polymerase chain reaction was done to detect NDM-1 and OXA-23.

RESULTS

Out of 231 samples, 101 samples yielded significant growth. These 38 samples were Gram-negative bacilli which were resistant to carbapenems. Out of the 38 which showed carbapenem resistance, 23 were MHT positive. Out of the 23 MHT-positive isolates, 8 (21.05%) were positive for NDM-1 gene and only 1 (2.6%) was positive for the OXA-23 gene.

CONCLUSION

This study has shown that carbapenem-resistant isolates from all the CA urinary tract-infected patients were 52.77% and most of them were Klebsiella. About 21% of them harbored the NDM-1 gene whereas only 2% had the OXA-23 gene. There has been an alarming increase in the spread of carbapenem resistance.