Extended Spectrum Beta-Lactamases (ESBL) is one of the resistance mechanisms responsible for emergence of antimicrobial resistance (AMR). The occurrence of ESBL producing bacteria in the environment might serve as a resistance reservoir and pose a serious impact on human health. This study investigated the occurrence of ESBL producing bacterial isolates from pharmaceutical waste dumping sites. Soil samples were collected for the purpose and total 42 bacterial isolates were recovered and 17 different genera were identified. Preliminary screening was done using antimicrobial resistance to third generation cephalosporins and further confirmation by double disc diffusion synergy test (DDST). The isolates were most susceptible to cefotaxime (43%) followed by ceftriaxone (38%). In contrast, maximum resistance was observed for aztreonam (83%) and ceftazidime (80.9%) during in-vitro antibiotic cultural sensitivity assay. 51.51% isolates were confirmed as ESBL producers by DDST. Statistical analysis revealed the significant correlation between ESBL production and Multiple antibiotic resistance (MAR) score with p<0.05 for chi-square value of 38.44 at degree of freedom 5. All ESBL producers were having MAR score ranging between 0.8-1.0. Molecular characterization of ESBL genes to understand the specific resistance mechanisms and potential transmission pathways may help in a stronger understanding of the study. The absence of data on the potential impact of these ESBL-producing bacteria on human health and the lack of a longitudinal study design may limit the broader implications of the findings. Incidence of highly resistant bacterial strains in the environmental settings should not be overlooked and strict acquiescence to waste management guidelines is needed.

Antimicrobial resistance, ESBL, cephalosporins, pharmaceutical waste, DDST

Incidence of antimicrobial resistant strains in pharmaceutical waste dumping sites urges the need of impactful waste disposal policies for Pharmaceutical companies so that release of such notorious superbugs in the environment can be controlled. Cefotaxime can be a drug of choice to treat infections due to these organisms but to comprehend the transmission dynamics and molecular interactions between environmental and clinical isolates there is still a scope of extensive research.

Arun Singha, Bharti Minhas, Naveen Minhas and Diksha Thakur (2023). Phenotypic Characterization of Extended Spectrum Beta-lactamase (ESBL) Producing Bacterial Isolates Recovered from Pharmaceutical Waste Sites. Biological Forum – An International Journal, 15(11): 186-192.