Azithromycin (AZM) is a macrolide antibiotic and a derivative of erythromycin. Erythromycine methyl substituted nitrogen at position 9 becomes AZM (Mutak, 2007; Xiang et al., 2020) (Fig. 1).
AZM is an antibiotic which is widely used in the treatment of bacterial infections such as streptococcal pharyngitis, pneumonia, diarrhea and intestinal inflammation (Talaiekhozani et al., 2020). It can also create an enhanced spectrum and potency against bacteria compared with other macrolides and superior stability in acidic media (Zeng et al., 2014). AZM not only can be used against atypical pathogen but also be effective against gram positive and gram-negative bacteria (Lalak and Morris, 1993; Retsema et al., 1990; Dunkin et al., 1988).
In this century, Major concerning issues are pharmaceuticals for their widespread use and frequent exposure in the water cycle. They can mix with water bodies from different ways, such as a human consumption, use of wastewater treatment plants sludge as fertilizers, hospitals effluents or unseemly disposal of unused or expired medicines and aquaculture farms (Da Le et al., 2021; Franchi et.al.2011). (“Occurrence and ecological risks of pharmaceuticals in a Mediterranean river in Eastern Spain – Science Direct,” n.d.). After wreckage, these residue scan be excreted unchanged, or as metabolites, which might be more toxic substances than native compounds (Lalović et al., 2017). As a result, antimicrobial resistance is a great threat for human being which is caused by antibiotics residue in environment (Hendriksen et al., 2019). Due to the unregulated use of antibiotics in human and animals, lack of wastewater treatment, and poor sanitation, it is estimated that more than 40% death associated with resistant pathogens in 2050 will be occurred in low and medium-income countries in Asia (Singh et al., 2019; Coyne et al., 2019; Kakkar et al., 2018).
The use of antibiotics in Bangladesh is increasing day by day (Angeles et al., 2020), they are not only limited to human healthcare but also widely used in animal husbandry (Roess et al., 2013). Poultry and dairy farming are a common practice in the rural area of Bangladesh, for the lack of knowledge sometimes high dose of antibiotics are applied. The use of antibiotics in animal farming not limit to treat bacterial related disease, but also to enhance the growth and to prevent infections (He et al., 2015; Jechalke et al., 2014; Grijalva et al. 2009). These antibiotics excreted and directly leaching to the water, sometimes the byproducts produced from these farming used as fish feed and there become a great source of water contamination (“Global trends in antimicrobial resistance in animals in low- and middle-income countries | Science,” n.d.). So, the continuous impute of antibiotics in the aquatic environment may lead to an adverse effect on aquatic organism (Hernando et al., 2006). Up to 95% administrated antibiotics to human and animal may be excreted to environment without metabolized (Hirsch et al., 1999). In Bangladesh waste water treatment plant not designed yet to remove completely the antibiotics from the industrially produced waste water (“Strategic Survey of Therapeutic Drugs in the Rivers Po and Lambro in Northern Italy | Environmental Science & Technology,” n.d.)(Analysis, Removal, Effects and Risk of Pharmaceuticals in the Water Cycle, 2007). As Bangladesh is a poor country, its healthcare system also very poor, and over all these the regulatory authorities cannot control the purchase and use of antibiotics both for animal and human, this situation becomes vulnerable for the country to control the antimicrobial resistant pathogens (Hossain et al., 2017; Hossain et al., 2018).
There are some reports already existing for AZM analysis in biological samples, including serum, tissues, and plasma. These methods followed bioassay, which are laborious and time consuming (Riedel et al., 1992). In some reports using High-performance liquid chromatography (HPLC) with ultraviolet detector (UVD) also described (Al-Rimawi and Kharoaf, 2010; El-Gindy et al., 2011; Shaikh et al., 2008; Yang et al., 2009). Due to not specific UV chromophore, HPLC-UVD sensitivity not so good, to increase sensitivity, precolumn derivatization followed by fluorescence also used (Bahrami and Mohammadi, 2006; Bahrami et al., 2005). However, derivatization process is laborious, expensive, time consuming and also have the result reproducibility problem. The liquid chromatography couple with mass spectrum (LC-MS) and tandem mass spectrum which is (LC-MS/MS) (Chen et al., 2006; Xu et al., 2008; Shen et al., 2010) the most recent and advantage technique.
The aim of this study is to develop an LLE method to analyze AZM residue using LC-MS/MS, and to monitor the contamination level of river and fish farm water in Bangladesh. To the best of our knowledge there is no LLE method available to analyze AZM residue in water and also no study report yet has been reported about AZM contamination level of Bangladesh River and fish farm water.