# Isothiocyanates: An Overview of Their Antimicrobial Activity against Human Infections
## 4 Isothiocyanates Antimicrobial Properties against Human Pathogens
### Campylobacterbacter Jejuni  
_Campylobacter jejuni_ is the main cause of human enteric infections in developed and developing countries [82]. Over the years, new undescribed _Campylobacter_ species were identified, and the increased number of _Campylobacter_ antibiotic-resistant strains [83; 84] has promoted research activities aimed at finding new therapeutic approaches.  
In order to analyze the antimicrobial activity of ITCs against C. _jejuni_ strains, [PERSON] et al. [53] tested the antimicrobial property of the following commercially available ITCs: AITC, BITC, ethyl ITC, and 3-methylsulfonylpropyl ITC. Each of those ITCs was evaluated against 24 C. _jejuni_ strains including the reference strain NCTC 11168 and clinical isolates from various origins (chicken feces, human infections--blood or feces--and contaminated processed meats) some of these with different antibiotic-resistant phenotypes [53]. BITC was the most effective ITC against sensitive and resistant bacteria included in the study. Indeed only 1.25 \(\upmu\)g/mL of BITC was capable of counteracting the growth of the most sensitive _C. jejuni_ and only 5 \(\upmu\)g/mL of BITC was sufficient to inhibit the growth of nine more resistant strains. AITC was also active against all the bacteria, but its efficacy was less than that of BITC (20 \(\upmu\)g/mL of AITC were required to exert a similar effect to BITC against resistant _C. jejuni_ strains). No positive results were obtained by testing the other ITCs included in the study. These findings were indicative of a marked antimicrobial activity of BITC against _C. jejuni_ and a higher antimicrobial potential compared to AITC [53].  
In addition, in order to clarify the BITC antibacterial mechanism of action against _C. jejuni_ the transcriptomic profiles of _C. jejuni_ NCTC11168 treated with BITC were analyzed using a microarray approach [54]. Results indicated that BITC treatment induced an increased expression levels of genes involved in the heat shock response pathways such as _clpB_ (ATP-dependent dis-aggregase), _hrcA_ (heat-inducible transcriptional regulator), _dnaK_ (chaperone), _grpE_ (co-chaperone of _dnaK_ and nucleotide exchange factor), _groES_ (chaperone), _cbpA_ (_dnaJ_-like protein) and _Cj0760_ (hypothetical protein, metallo-\(\upbeta\)-lactamase superfamily). Furthermore, BITC determined the upregulation of _trxA_ (thioredoxin) gene involved in iron-sulfur cluster homeostasis and _sodB_ (superoxide dismutase) gene involved in the oxidative stress response. Additionally, BITC stimulated the upregulation of genes involved in energy metabolism such as _gapA_ (glyceraldehyde-3-phosphate dehydrogenase A) gene, _fba_ (fructose-bisphosphate aldolase) gene, _frdC_ (fumarate reductase, cytochrome b-556 subunit) gene and _frdB_ (fumarate reductase, iron-sulfur subunit) gene. Those results suggested that the antimicrobial action of BITC is exerted through triggering pathways inducing to heat shock and oxidative stress response, protein aggregation and to the dysfunction of energy metabolism leading to bacterial death [54].