“Antimicrobial bactericidal effects of antibiotics. It provides a survival

“Antimicrobial agent” is a general
term used to refer to any compound which include antibiotics, food
antimicrobial agents, sanitizers, disinfectants, and other substances that acts
against microorganisms. Antibiotics, on the other hand are antimicrobial agents
produced by bacteria, fungi or of synthetic in nature. Antibiotic resistance
refers to the ability of microorganisms to withstand the bacteriostatic and
bactericidal effects of antibiotics. It provides a survival benefit to the invading
microorganisms and under such circumstances it is difficult to eliminate the
infection caused by these microorganisms. The mechanisms by which
microorganisms exhibit resistance to antibiotics include drug inactivation or
modification, alteration of target site, alteration in the metabolic pathway,
and reduced drug accumulation (Katzung, 2004).

LAB produces a variety of
antimicrobial compounds, e.g. the pH-reducing fermentation products lactic and
acetic acids, as well as hydrogen peroxide, formic acid, propionic acid, and
diacetyl (Lindgren & Dobrogosz, 1990). The precise mechanism of
antimicrobial action is difficult to elucidate due to complex and commonly
synergistic interactions between different compounds (Corsetti, Gobbetti,
Rossi, & Daminani, 1998; Niku-Paavola, Laitila, Mattila-Sandholm,
&Haikara, 1999). Research has mainly been directed towards identifying
different antimicrobial substances, primarily antibacterial, in simple in vitro
systems, but little is known about the overall mechanisms of complex
preservation systems within food and feed environments (Earnshaw, 1992).
Studies on the effect of LAB on fungi are complicated by the sensitivity of
most fungi to the normal fermentation products lactic and acetic acids
(Bonestroo et al., 1993; Lindgren & Dobrogosz, 1990; Piard&Desmazeaud,

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Generally, food antimicrobial agents are not
used alone to control foodborne pathogens, but are included as components of
the multiple approaches to microbial control. Lactic acid bacteria (LAB) from
fermented products may act as a reservoir of antimicrobial-resistance genes
that could be transferred to pathogens, either in the food web or, more
importantly, in the gastrointestinal tract of human and animal (Belén Flórez et
al., 2005). However, there are different views pertaining to the resistance
susceptibility breakpoints of most antimicrobials in LAB (Charteris et al.,
2001; Danielsen and Wind, 2003). Distinguishing the intrinsic, nonspecific, and
acquired resistance is difficult as it requires antimicrobial-resistance
patterns of