Detection of Resistance Genes to Biocides in Bacteria Nosocomiales by Means the Chain Reaction of the Polymerase
Author(s): Céspedes PF, Jara MA, Navarro CO
Infections represent the greatest threat to animal and human health, for this reason since ancient times, ways to control them have been
sought, and in the first years of the 20th century, the first chemo-therapeutic molecules (sulfas) and the first antibiotic were developed.
(Penicillin), which were used clinically in the forties, managing to control infections that until then were extremely high morbidity and
difficult to treat. Nosocomial infections are those acquired in a hospital and manifested 48 to 72 hours after the admission of patients.
They are caused by ubiquitous, opportunistic and highly resistant bacteria, which preferentially affect those patients with varying degrees
of immune compromise, affecting their evolution and recovery. Disinfectants and antiseptics (biocides) are used in medical practice as an
essential part of the biosafety protocols adopted to minimize the spread of this type of infections among staff, patients and hospital facilities,
but even these compounds have shown resistance.
These bacteria have multiresistance phenotypes (defined as resistance to two or more antimicrobials) that reflect the great influence of
the hospital environment in the emergence of mechanisms of insensitivity to different toxic compounds, which are found in residual
concentrations (sub-lethal) in the environment, either by the acquisition of mutations or, by the acquisition of gene cassettes, which, in turn,
allow the selection of successful bacterial clones and the exchange of resistance genes included in integrons, plasmids and / or transposons.
These, together with the efflux pumps, explain the intimate relationship between multiple resistances to antimicrobials and that observed to
biocides.
Resistance to biocides represents one of the greatest threats to public health, because the mechanisms involved are characterized by
being nonspecific, affecting a wide range of substances not structurally related. For this reason, efforts have been made to complement
the epidemiological surveillance of antimicrobial resistance, investigating the resistance to biocides by means of molecular diagnostic
techniques, within which the detection of the genes involved by means of polymerase chain reaction delivers relevant information in the
development of new control strategies, vigorously adapting the protocols used to the epidemiological reality.
In response to this emerging need, this work has been focused on the detection of genes of resistance to biocides in nosocomial isolates, as
a first approach in national veterinary medicine, to provide knowledge that allows the control of this type of infections. None of the most
representative genes of the MFS families (qacA and qacB) and SMR (qacC and qacD) were detected in the 80 samples analyzed, obtained
from clinical-veterinary units of the University, from both the Bilbao Veterinary Hospital and of the Faculty Hospital. The concentrations of
biocides used in the clinical-veterinary units of the University were sufficient to inhibit the bacterial growth of samples taken directly from
the sprinklers and hand brushes, but not in the rest of the sampled places.
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