88
4.3 Resistance in Bacteria
The most well-known cases of resistance are documented through antibiotic use.
The misuse of antibiotics leads to a loss of the commensal bacteria, which are
responsible for the host welfare, especially in the gut, and this recklessness placed
us in a ‘post-antibiotic era’. Antibiotic induced dysbiosis is a major medical concern
in terms of life-threatening and health costs. Pathobionts and pathogens thrive during dysbiosis mainly because they are capable to adapt and overgrow in those new
conditions which can lead to opportunistic infections (Round and Mazmanian 2009;
Nicholson et al. 2012; Rigottier-Gois et al. 2014).
The treatments with antibiotics increase the frequency of multi drug resistant
bacteria, like Vancomycin Resistant Enterococci (e.g. Enterococcus faecalis and
E. faecium), Clostridioides difficile, Mycobacterium tuberculosis, Escherichia coli,
Klebsiella pneumoniae, Neisseria gonorrhoeae, and Methicillin Resistant
Staphylococcus aureus (MRSA). After the antibiotic use is interrupted, the gut
microbiota restoration can be rapid or take months to arise depending on the infliction (Jernberg et al. 2007; Brandl et al. 2008; Ubeda et al. 2010; Becattini et al.
2016). Multi drug resistance correspond to a high burden and a prevalent hazard to
public health being associated with nosocomial infections widespread in the community, increased morbidity and mortality, high healthcare costs (i.e. annually
between $21 billion and $34 billion in the United States) and antibiotic use (Singh
2013; Tanwar et al. 2014). Tuberculosis is one of the most prevalent bacteria hazards. The cases related to multi drug resistant tuberculosis were about 480,000, in
2014, yet only a quarter (123,000 cases) were detected and reported; however, only
half were successfully treated. The burden of tuberculosis is much higher considering that only 3.3% of the patients were infected with a multi drug resistant strain.
In 2017, WHO published an antibiotic resistant ‘priority pathogens’ list with 12
families of bacteria that pose a threat to human health, to instigate vigilance and
promote research and development of new antibiotics (Table 4.2). The list includes
multi drug resistant bacteria and nosocomial threats divided into 3 categories
according to the urgency for new antibiotics: critical, high and medium priority.
Table 4.1 (continued)
Antimicrobial class
Example of antimicrobial(s)
Important antimicrobials
Aminocyclitols
Spectinomycin
Cyclic polypeptides
Bacitracin
Nitrofurantoins
Nitrofurantoin
Nitroimidazoles
Metronidazole
Pleuromutilins
Retapamulin
Adapted from WHO (2018a)
M. Santana et al.
4.3 Resistance in Bacteria
The most well-known cases of resistance are documented through antibiotic use.
The misuse of antibiotics leads to a loss of the commensal bacteria, which are
responsible for the host welfare, especially in the gut, and this recklessness placed
us in a ‘post-antibiotic era’. Antibiotic induced dysbiosis is a major medical concern
in terms of life-threatening and health costs. Pathobionts and pathogens thrive during dysbiosis mainly because they are capable to adapt and overgrow in those new
conditions which can lead to opportunistic infections (Round and Mazmanian 2009;
Nicholson et al. 2012; Rigottier-Gois et al. 2014).
The treatments with antibiotics increase the frequency of multi drug resistant
bacteria, like Vancomycin Resistant Enterococci (e.g. Enterococcus faecalis and
E. faecium), Clostridioides difficile, Mycobacterium tuberculosis, Escherichia coli,
Klebsiella pneumoniae, Neisseria gonorrhoeae, and Methicillin Resistant
Staphylococcus aureus (MRSA). After the antibiotic use is interrupted, the gut
microbiota restoration can be rapid or take months to arise depending on the infliction (Jernberg et al. 2007; Brandl et al. 2008; Ubeda et al. 2010; Becattini et al.
2016). Multi drug resistance correspond to a high burden and a prevalent hazard to
public health being associated with nosocomial infections widespread in the community, increased morbidity and mortality, high healthcare costs (i.e. annually
between $21 billion and $34 billion in the United States) and antibiotic use (Singh
2013; Tanwar et al. 2014). Tuberculosis is one of the most prevalent bacteria hazards. The cases related to multi drug resistant tuberculosis were about 480,000, in
2014, yet only a quarter (123,000 cases) were detected and reported; however, only
half were successfully treated. The burden of tuberculosis is much higher considering that only 3.3% of the patients were infected with a multi drug resistant strain.
In 2017, WHO published an antibiotic resistant ‘priority pathogens’ list with 12
families of bacteria that pose a threat to human health, to instigate vigilance and
promote research and development of new antibiotics (Table 4.2). The list includes
multi drug resistant bacteria and nosocomial threats divided into 3 categories
according to the urgency for new antibiotics: critical, high and medium priority.
Table 4.1 (continued)
Antimicrobial class
Example of antimicrobial(s)
Important antimicrobials
Aminocyclitols
Spectinomycin
Cyclic polypeptides
Bacitracin
Nitrofurantoins
Nitrofurantoin
Nitroimidazoles
Metronidazole
Pleuromutilins
Retapamulin
Adapted from WHO (2018a)
M. Santana et al.