performed on a long-term field experiment where various antibiotics were repeatedly
applied, evidenced for enhanced dissipation of an impressive range of antibiotics
(sulfamethazine, tylosin, chlortetracyclin, erythromycin, clarithromycin, and
azithromycin) in exposed field plots as compared to control field plots
[109, 117]. The number of studies reporting the degradation of different antibiotics
in soils is important [124, 340]. Differences observed between studies for a given
antibiotic are most likely due to variations in soil type, antibiotic concentrations, and
environmental conditions.
Numerous bacterial strains able to degrade antibiotics have been isolated from
various matrices including patient, animal, sediment, sludge, manure, and soil. For
soils it includes strains belonging to the genera Microbacterium sp. (sulfamethazine,
sulfadiazine, and sulfamethoxazole) [109, 347, 348], Bacillus sp. (penicillin) [110],
Escherichia sp. (sulfonamides including sulfamethazine and sulfamethoxazole)
[349],
Stenotrophomonas
sp.,
(tetracycline)
[350],
Ochrobactrum
sp. (sulfamethoxazole and erythromycin) [351, 352], Labrys sp. (fluoroquinolones
and sulfamethoxazole) [88, 351], and Gordonia sp. (sulfamethoxazole) [351]; the
orders Burkholderiales, Caulobacterales, Xanthomonadales, Pseudomonadales,
Enterobacteriales, and Rhizobiales; and the phyla Bacteroidetes (penicillin and
neomycin) [112]. In this regard, bioaugmentation of sulfonamide-spiked soil microcosms with Microbacterium sp.C448 [109] was shown to reduce the persistence of
antibiotic residues in soils and all associated side effects [353, 354].
3.6 Antiseptics and Disinfectants
Antiseptics and disinfectants, sometimes called biocides, are chemicals commonly
used in a variety of medical and domestic settings to prevent or kill the growth of
microorganisms. In general, biocides are less specific than antibiotics as their action
mode has a broad spectrum of activity, generally not fully understood [355]. Among
widely used biocides, triclosan has raised special concern due to its weak demonstrated benefit [356] and potential toxic effects on human health [357, 358]. At low
concentrations, triclosan is a bacteriostatic, while at high concentrations, it is bactericidal agent effective against many types of Gram-positive and negative
non-sporulating bacteria, some fungi, and certain parasites [359–363]. Although
the use of triclosan was restricted in certain types of products [364–366], it is still
found in many care products such as toothpaste, mouthwash, hand sanitizer, and
surgical soaps. Due to its widespread use and incomplete removal from wastewater
treatment plants [367–369], triclosan is frequently detected in several environmental
matrices such as soil and surface waters [222, 370–373]. Triclosan was found to
bioaccumulate in aquatic species, algae, snails, and earthworms [71, 373–375] in
which it caused toxic effects [376–383]. Similarly, plants such as pumpkin, zucchini,
onion, and tomato have been shown to bioaccumulate triclosan in the edible parts,
thereby leading to the contamination of the food chain [384–386].
278
S. Gallego and F. Martin-Laurent
applied, evidenced for enhanced dissipation of an impressive range of antibiotics
(sulfamethazine, tylosin, chlortetracyclin, erythromycin, clarithromycin, and
azithromycin) in exposed field plots as compared to control field plots
[109, 117]. The number of studies reporting the degradation of different antibiotics
in soils is important [124, 340]. Differences observed between studies for a given
antibiotic are most likely due to variations in soil type, antibiotic concentrations, and
environmental conditions.
Numerous bacterial strains able to degrade antibiotics have been isolated from
various matrices including patient, animal, sediment, sludge, manure, and soil. For
soils it includes strains belonging to the genera Microbacterium sp. (sulfamethazine,
sulfadiazine, and sulfamethoxazole) [109, 347, 348], Bacillus sp. (penicillin) [110],
Escherichia sp. (sulfonamides including sulfamethazine and sulfamethoxazole)
[349],
Stenotrophomonas
sp.,
(tetracycline)
[350],
Ochrobactrum
sp. (sulfamethoxazole and erythromycin) [351, 352], Labrys sp. (fluoroquinolones
and sulfamethoxazole) [88, 351], and Gordonia sp. (sulfamethoxazole) [351]; the
orders Burkholderiales, Caulobacterales, Xanthomonadales, Pseudomonadales,
Enterobacteriales, and Rhizobiales; and the phyla Bacteroidetes (penicillin and
neomycin) [112]. In this regard, bioaugmentation of sulfonamide-spiked soil microcosms with Microbacterium sp.C448 [109] was shown to reduce the persistence of
antibiotic residues in soils and all associated side effects [353, 354].
3.6 Antiseptics and Disinfectants
Antiseptics and disinfectants, sometimes called biocides, are chemicals commonly
used in a variety of medical and domestic settings to prevent or kill the growth of
microorganisms. In general, biocides are less specific than antibiotics as their action
mode has a broad spectrum of activity, generally not fully understood [355]. Among
widely used biocides, triclosan has raised special concern due to its weak demonstrated benefit [356] and potential toxic effects on human health [357, 358]. At low
concentrations, triclosan is a bacteriostatic, while at high concentrations, it is bactericidal agent effective against many types of Gram-positive and negative
non-sporulating bacteria, some fungi, and certain parasites [359–363]. Although
the use of triclosan was restricted in certain types of products [364–366], it is still
found in many care products such as toothpaste, mouthwash, hand sanitizer, and
surgical soaps. Due to its widespread use and incomplete removal from wastewater
treatment plants [367–369], triclosan is frequently detected in several environmental
matrices such as soil and surface waters [222, 370–373]. Triclosan was found to
bioaccumulate in aquatic species, algae, snails, and earthworms [71, 373–375] in
which it caused toxic effects [376–383]. Similarly, plants such as pumpkin, zucchini,
onion, and tomato have been shown to bioaccumulate triclosan in the edible parts,
thereby leading to the contamination of the food chain [384–386].
278
S. Gallego and F. Martin-Laurent