A recent study by a joint Moroccan-Egyptian research team, published in the journal Scientific Reports, revealed the discovery of Salmonella bacteria, which is a “facultative anaerobic” bacterium, in the groundwater of one of Morocco’s plains. The study found that the species isolated from the water were resistant to antibiotics.
One of the study’s lead researchers said: “A study will then be conducted on groundwater samples that will be collected from several regions in Egypt, in cooperation with the Moroccan research team, to find out whether the same problem is recurring or not.”
The study explains that the danger of finding these antibiotic-resistant bacteria in groundwater is that they can be transmitted again to humans, if they eat the meat of an animal that used that water, or if the water is used to irrigate agricultural crops that humans later consume.
Salmonella strains cause gastroenteritis, which is usually mild and does not require treatment, but can be fatal in newborns, young children and people with weakened immune systems. It is therefore important to detect antibiotic-resistant bacteria in groundwater samples.
Salmonella has developed resistance to various antimicrobials since the early 1990s, and this phenomenon is increasing, posing a threat to global health, as shown in the same study.
Salmonella bacteria are classified as “facultative anaerobes,” meaning they prefer oxygen, but they can also adapt to oxygen-deprived environments.
During the study, researchers collected 200 samples from 43 wells over four seasonal campaigns in 2017 and 2018. The samples were examined for the presence of Salmonella bacteria, and then tested for resistance to 16 antibiotics.
The researchers found that 58.1% of the isolated Salmonella species were multidrug-resistant strains and determined the resistance levels among the strains, where 38.7% were resistant to at least 6 antibiotics, 19.4% (9 antibiotics) and 9.7% (4 to 7 antibiotics), 6.5% (at least 11 antibiotics) and 3.2% (12 antibiotics).
High levels of resistance were observed to the antibiotic cefepime (61.29%), the antibiotic imipenem (54.84%), the antibiotic ceftazidime (45.16%), the antibiotic ofloxacin (70.97%) and the antibiotic ertapenem (74.19%).
The researchers said in the study that it is important to monitor and regulate the growth of multidrug-resistant bacteria to prevent deterioration of groundwater quality.
“Salmonella” is not the only one in the world, and “drug-resistant salmonella” is not the only “facultative anaerobic” bacteria whose presence in groundwater has been highlighted by studies, such as a US study published in March 2022 in the journal “Salmonella.” Water” revealed the presence of Escherichia coli and enterococci, across 443 samples isolated from Kentucky and 45 samples from Florida.
A Chinese study published in the journal “ISME Communications” revealed the infiltration of another “facultative anaerobic” bacteria, namely “Acinetobacter acinetobacter”, into the aquifer of the livestock environment in various regions of China.
Regarding how these bacterial species, including Salmonella, infiltrate underground aquifers, the same study adds that agricultural, urban and industrial activities have all contributed to potential bacteriological contamination of groundwater supplies in recent decades, worldwide.
She also points out that “antibiotics are commonly used in agriculture to prevent and treat diseases while promoting growth. As a result, animal feces can contain antibiotic-resistant bacteria, and these leach into the aquifer when the feces are used as animal fertilizer. agricultural land. Improper treatment of wastewater and waste allows bacteria to leach into groundwater. On the other hand, increased frequency and intensity of precipitation due to climate change leads to surface water runoff that carries bacteria from the surface to groundwater.
During the study, researchers collected 200 samples from 43 wells during four seasonal campaigns in 2017 and 2018 (Pixabay)
The next step the Egyptian-Moroccan research team will work on after diagnosing the problem is to find out how salmonella was able to adapt to an oxygen-deprived environment in the groundwater layers, which could then be useful in developing a treatment that eliminates these bacteria. They will also work on developing filters that can treat bacteria containing salmonella.
