Emerging resistance to aminoglycosides in lactic acid bacteria of food origin—an impending menace

Abstract

Aminoglycosides are the most preferred choice of therapy against serious infections in humans. Therefore, its use in animal husbandry has been strictly regulated in the EU, UK, and USA to avoid the hazards of aminoglycoside resistance in gut microflora. Nevertheless, aminoglycosides are recommended for prophylaxis and therapeutics in food animals and agriculture owing to its bactericidal nature. In the recent past, the global surge in aminoglycoside-resistant lactic acid bacteria (LAB) from food sources has been noticed that might question its continued use in animal husbandry. Upon antibiotic administration, a selective pressure is created in the gut environment; in such instances, LAB could act as reservoirs of antibiotic resistance which may facilitate their transfer to pathogenic organisms contradicting its probiotic and industrial significance. This may be a risk to human health as the presence of one aminoglycoside resistance gene renders the bacteria tolerant to almost all antibiotics of the same class, thereby challenging its therapeutic efficacy. Low doses of aminoglycosides are recommended in farm animals due to its toxic nature and insolubility in blood. However, recent investigations indicate that use of aminoglycosides in sub-lethal concentrations can trigger the selection and conjugal transfer of aminoglycoside resistance in probiotic LAB. Resistance to erythromycin, tetracyclines, and fluoroquinolones in LAB were reported earlier to which immediate regulatory measures were adopted by some countries. Paradoxically, lack of regulations on antibiotic use in farms in most developing countries makes them a potential source of antibiotic resistance and its uncontrolled spread around the globe. The prevalence of aminoglycoside resistance was observed in enterococci from food origin earlier; however, its emergence in lactobacilli and pediococci suggests its spread in probiotic cultures which prompts immediate precautionary methods. This review highlights the emergence and hazards of aminoglycoside-resistant LAB which is in prime commercial demand both for preparing fermented food and also pharma-based therapeutics. It further focuses on the mode of aminoglycoside resistance and its occurrence in food-grade LAB, thus relating to its role in worldwide transfer via the food chain in spite of its limited use as compared to other antibiotics.

Gut commensal bacteria show beneficial properties as wildlife probiotics

“…Very recent publications have reported the emerging resistance of LAB to gentamycin, kanamycin, and streptomycin. 72 Although LAB, such as lactobacilli and pediococci, are generally considered as safe, their antibiotic susceptibility should be well assessed before their application as probiotics. 73 Our data demonstrate that some LAB isolates, especially strains of Pediococcus, show significant antibiotic resistance.…”

Antibiotic Resistance in Lactic Acid Bacteria

“…The resistance to aminoglycosides in LAB has not been reported, although in recent years LAB isolated from farm origin show resistant to gentamicin, kanamycin, and streptomycin, whose resistance mechanism is associated to impaired transport or enzymatic inactivation by three main aminoglycoside-modifying enzymes (AMEs) as N-acetyltransferases (AACs), O-phosphotransferases (APHs), and O-nucleotidyltransferases (ANTs) encoded by MGEs (mobile genetic elements) like transposons and insertion sequences [40].…”

“…• Enzymatic inactivation such as for aminoglycosides (neomycin, kanamycin, streptomycin) or quinolones (ciprofloxacin, norfloxacin, nalidixic acid) prevents the binding of these antibiotics with their specific targets, as observed for Lactobacillus and Enterococcus for the 16S rRNA of the 30S ribosomal bacterial subunit and DNA gyrase, respectively, that explains the intrinsic resistance to both groups of antibiotics [29,40].…”

Detection of acetyltransferase modification of kanamycin, an aminoglycoside antibiotic, in bacteria using ultrahigh‐performance liquid chromatography tandem mass spectrometry

“…Bacterial resistance to various classes of antibiotics, such as aminoglycosides, has been encountered at increasing rates . Enzymatic modification of aminoglycosides is the most common resistance mechanism resulting in loss of antibacterial activity .…”

“…Bacterial resistance to various classes of antibiotics, such as aminoglycosides, has been encountered at increasing rates. [18][19][20] Enzymatic modification of aminoglycosides is the most common resistance mechanism resulting in loss of antibacterial activity. [21][22][23][24] Aminoglycoside modification transpires through three classes of enzymes: aminoglycoside acetyltransferases (AACs), nucleotidyltransferases and phosphotransferases.…”