**Abstract**

Antibiotics were the world's great therapeutic hope after the Second World War, but today, unmonitored use has become one of the greatest risks for humanity. Without overestimation, one of the last scientific books on antibiotics was entitled: Antibiotics, the perfect storm. Before to environmental contamination by antibiotics, the pathogens got resistant to them. Because of the radical changes that antibiotics have brought about, they can generate new resistant bacteria in the environment that were previously harmless. These microorganisms will be exposed to concentrations of antibiotics never reached or will be exposed to unknown molecules that, for many of them, in certain environments, have never been exposed before. Initially, many of these antibiotics did not penetrate soils with high agricultural production, but in the following decades, they were even interspersed into crops. Nowadays, hundreds of tons of antibiotics are dumped into rivers and the sea. Many hospitals have water treatment facilities to prevent significant contamination, but not all companies, farms, and hospitals in developed, emerging, or poor countries apply wastewater treatment. Antibiotics are incorporated into wild microorganisms and plants, triggering a broad "unnatural" resistance, which will rapidly incorporate this information into the genome of other pathogenic microorganisms by horizontal transfer. On the other hand, antibiotics could be incorporated into drinking water and water intended for human or agricultural consumption that travels without being detected or monitored. This review covers the most important aspects of environmental pollution by antibiotics.

**Keywords:** antibiotics, water, hospitals, farms, livestock, soil, sea

## **1. Introduction**

Antibiotics exist in normal (low) concentration in nature [1–3]. Bacteria, fungi in general all organisms develop and metabolize these molecules to survive [4]. The discovery of penicillin split the history of humanity in two and that magnificent discovery is only comparable to the handling of electricity, atomic energy, space travel, and anesthesia, among others [5]. The penicillin and antibiotics brought about the saving of millions of lives, but their use and application were exaggerated and misguided to the point that antibiotics are used as food supplements in the

livestock, poultry, swine, and crop industries [6–9]. However, pharmaceutical antibiotics at a significant level in nature and different environments has been detected in previous studies and monitoring in plains, valleys, coast, and mountains, when were monitored in hospital wastewater, farms, rivers, and coastal water [10–13]. Antibiotics emerge as new environment contaminants as plastics, pesticides, among others. The main risk and concern as the pesticides are microbial antibiotics and multidrug resistance. The human being is developing littles Frankenstein, likely by carelessness and naivety, contrary to genetically modified organisms (GMOs) opinion, the scare of gene manipulation, and its ethical reflection by the Scientifics and public [14, 15]. The consumer has scary to GMOs, but without laboratory use, the human being is making GMOs resistant to antibiotics. The controversy is rising, why the public is concerned by artificial experiments but carefree by antibiotics pollutants? This environmental risk goes in the same way as global warming.

Probably some natural antibiotic-resistant bacteria in soil gain multidrug resistance consequence by human practices as livestock or water activities. However, antibiotics come to the soil by wastewater from human or animal feces together with the selection of antibiotic-resistant microbiome [16]. Antibiotics and bacteria remain in the soil until water carries them to stream or rivers or are transferred by

#### **Figure 1.**

**Water carries on antibiotics.** *Water from hospitals and farms could pass through sewage treatment, but in many countries, those health and environmental rules are not applied or respected, especially in developing countries by poor investment and low budget. Water is used for human consummation, livestock, poultry, swine, and soil irrigation to crop grass and agriculture plants. But lockdown animals, cattle, and others get sick and must be under antibiotic treatment. Then, this sanitary water passes directly to the sewer rarely treated and directly deposed in the streams and rivers. Antibiotics are used in some countries to yield more muscular biomass of livestock, poultry, and swine. This practice increases the level of antibiotics in soil, humans, flora, and fauna. Likely, some soils intersperse antibiotics in roots, stems, leaves, and fruits for human consummation. Even, antibiotics in the soil are absorbed by bacteria, fungi, protists, and invertebrates. Soils stock, pick up, and pour antibiotics in streams, then to rivers and finally to the sea. The pharmaceutical antibiotics were poured into the sea for 70 years. Surely the antibiotics levels in nature and water were not the same before the pharmaceutical antibiotic' revolution and production. This image is an actual case in South America, where some hospitals lack the budget to invest in the sewage treatment plant. Near this real example, there are other little villages where its hospital has two water treatment plants, one for human consummation and the other for sewage. In that case, contaminated hospital water never goes back to flow, however, many farms invest weakly in the water treatment process, ejecting polluted water to the environment with antibiotics and pesticides.*

**165**

*Pharmaceutical Antibiotics at a Significant Level in Nature: From Hospitals, Livestock…*

**2. Antibiotics real state consummation and biodegradability**

roots in plants reaching leaves, which will be consumed by insects, incorporating

Tons of pharmaceutical antibiotics have been produced by the industry. The worldwide production of antibiotics is estimated to be in the order of 100.000 tons per year [17], and 73% in the world and 80% in the United States is used for livestock consummation [18]. Different from the European Union, where the amount of antibiotic used is 60% for humans and 40% for animals and crops [19]. The great threat as warned by the WHO is to increase the resistance to antibiotics not only by pathogens but also by environmental organisms, which can lead to possible environmental damage (https://www.who.int/news/item/07-11-2017-stop-usingantibiotics-in-healthy-animals-to-prevent-the-spread-of-antibiotic-resistance). Now WHO is recommending avoiding the use of antibiotics in healthy animals. Antibiotics were approved in the USA in the next order: sulfonamides in 1935, penicillin in 1941, aminoglycosides in 1944, cephalosporins in 1945, chloramphenicol in 1949, tetracyclines in 1950, macrolides/lincosamides/streptogramins in 1952, glycopeptides in 1956, rifamycins in 1957, nitroimidazoles in 1959, quinolones in 1962, trimethoprim in 1968, oxazolidinones in 2000, lipopeptides in 2003 [20]. **Table 1** relates the antibiotics with their molecular functional group and in the last column their resistance model in microorganisms. Another problem is that antibiotics are not used alone and come with stimulators and enhancers, such as clavulanic

**Class Example(s) Functional group or whole molecule Model(s) of** 

**resistance**

Hydrolysis, efflux, altered target

Phosphorylation, acetylation, nucleotidylation, efflux, altered target

Reprogramming peptidoglycan biosynthesis

*DOI: http://dx.doi.org/10.5772/intechopen.95368*

new molecular information to wild species (**Figure 1**).

acid which helps overcome β-lactam resistance.

(ampicillin), cephalosporins (cephamycin), penems (meropenem), monobactams (aztreonam)

streptomycin, spectinomycin

teicoplanin

**β-Lactams** Penicillins

**Aminoglycoside**s Gentamicin,

**Glycopeptides** Vancomycin,

*Pharmaceutical Antibiotics at a Significant Level in Nature: From Hospitals, Livestock… DOI: http://dx.doi.org/10.5772/intechopen.95368*

roots in plants reaching leaves, which will be consumed by insects, incorporating new molecular information to wild species (**Figure 1**).
