Netilmicin Sulfate

Antibiotic residues in food chain have raised concerns regarding their toxicity and involvement in antimicrobial resistance. However, most existing antibiotic biosensors are primarily applicable to liquid food samples. Given the complex matrix characteristics of foods, there is an urgent need for the development of effective antibiotic detection platforms that exhibit high universality and flexibility. Porous microneedles (PMN) are microdevice structures with needle-like shapes and microscale pores throughout their composition, which facilitate rapid sampling. Consequently, the integration of PMN with biosensors holds significant promise for the detection of antibiotic residues in complex food samples.

In this study, hydrogel-forming PMN are fabricated by leveraging the oxygen-production capacity of thylakoid to generate bubbles and form porous structures. These PMN are then integrated with a fluorescence aptasensor for the quantification of the antibiotic netilmicin. The aptasensor consists of a netilmicin (NET) aptamer with stem loop and hairpin structure, which facilitated the binding of SYBR Green I to produce a fluorescent signal. In the presence of NET, the complete binding between NET and the aptamer results in a reduction of fluorescence intensity, thereby generating a detectable signal change for the detection of NET. Utilizing capillary action accelerate fluid extraction (2.9 times faster than nonporous microneedles) and a large specific surface area (5.1072 m²/g) conducive to aptasensor adsorb, the PMN achieve efficient capture and quantification of antibiotic with limits of detection and quantitation of 5.99 nM and 19.8 nM, respectively.

Porous microneedles with tunable porosity and desirable mechanical properties are successfully fabricated. The integration of PMN with aptasensor enable the efficient detection of netilmicin in fish, milk and river water samples, demonstrating high recovery rates. The PMN represent potential tools for the convenient and rapid detection of antibiotic residues within complex food matrices, thereby enhancing food safety monitoring.

Background Antimicrobial resistance has developed significant importance as a worldwide health concern more so in the 21^st century. This is more specifically observed among the Enterobacteriaceae family, the major group of Gram-negative bacteria. Resistance to carbapenems and colistin antimicrobials from the reserve group, in critical infection treatment poses a substantial therapeutic challenge. This study aims to detect resistance to both carbapenems and colistin in Enterobacteriaceae isolates, emphasizing the importance of monitoring. Materials and methods A laboratory-based study investigated 82 Carbapenem-Resistant Enterobacteriaceae (CRE) isolates from hospitalized patients at Krishna Hospital & Medical Research Centre, Karad, India, for two years (November 2021-November 2023). The Kirby-Bauer disc diffusion method was used to determine the antimicrobial susceptibility following Clinical Laboratory Standards Institute 2022 recommendations. To validate Carbapenem-Resistant Enterobacteriaceae isolates, the Modified Carbapenem Inactivation Method (mCIM) was used, and Colistin resistance was ascertained using Broth Microdilution Susceptibility Testing (BMD). Results Among 309 Enterobacteriaceae isolates, 82 (26.5%) exhibited carbapenem resistance, with 75 confirmed by Modified Carbapenem Inactivation Method (mCIM) testing. For patients in the age group 51-60 years (20%), with men being the most prevalent, the predominance of CRE isolates was from the Intensive Care Unit (44%), mostly from urine samples (34.6%). The most dominant CRE was Klebsiella pneumoniae (62.7%), followed by Escherichia coli (32%). Colistin resistance was found in 14 (18.7%) of CRE isolates, with the highest minimum inhibitory concentration (MIC) at 4 µg/mL (n=10) and 16 µg/mL (n=4). Colistin-resistant isolates (n=10) were sensitive to amikacin (71.4%) and resistant to many antibiotics. Conclusion The extreme rise of colistin-resistant cases among CRE in healthcare settings is a solemn alarm. Among the most effective treatments, aminoglycosides amikacin and netilmicin show the greatest sensitivity against these colistin-resistant CRE infections. The findings stress the difficulties in treating such infections and the dire need for solid antimicrobial stewardship and novel therapeutic strategies.