Uso de biocidas y mecanismos de respuesta bacteriana / Use of biocides and bacterial response mechanisms

La constante aparición de microorganismos que incrementan su tolerancia a sustancias utilizadas para su control como los biocidas está generando atención en salud pública y debe ser estudiado, teniendo en cuenta los diversos riesgos que se pueden enfrentar principalmente en pacientes con alta susceptibilidad a las infecciones asociadas a la atención en salud, dado que estos biocidas son utilizados cotidianamente lo que ha generado mecanismos bacterianos como lo son la formación de biopelículas y aquellos que incrementan su tolerancia como la generación de bombas de flujo. Esta respuesta bacteriana a la presión de los biocidas se potencia por la aparición de microorganismos resistentes a los antimicrobianos de uso en el tratamiento y control de las infecciones lo que hace difícil el control de estos. Se realizó una revisión de literatura disponible en las bases de datos Proquest, ovid, Science direct, PubMed, donde se encontraron un total de 103 artículos y se seleccionaron 73, de acuerdo con el año de publicación en los idiomas español e inglés, que incluyeron estudios descriptivos y de revisión. El objetivo de este artículo fue realizar una revisión acerca de los principales mecanismos de acción de biocidas y la respuesta de tolerancia que presentan los microorganismos frente a estos; lo que conlleva a la reflexión sobre las implicaciones del uso de estas sustancias sobre la salud humana.

The constant appearance of microorganisms that increase their tolerance to substances used for their control such as biocides is generating attention in public health and should be studied, taking into account the various risks that can be faced mainly in patients with high susceptibility to infections associated with health care, given that these biocides are used on a daily basis, which has generated bacterial mechanisms such as the formation of biofilms and those that increase their tolerance, such as the generation of flow pumps. This bacterial response to the pressure of the biocides is enhanced by the appearance of microorganism's resistant to the antimicrobials used in the treatment and control of infections, which makes their control difficult. A literature review was made available in the databases Proquest, ovid, Science direct, PubMed, where a total of 103 articles were found and 73 were selected, according to the year of publication in the Spanish and English languages, which included Descriptive and review studies. The objective of this article is to carry out a review about the main action mechanisms of biocides and the tolerance response presented by microorganisms against them; which leads to reflection on the implications of the use of these substances on human health.

In vitro activity of a polyhexanide-betaine solution against high-risk clones of multidrug-resistant nosocomial pathogens.

OBJECTIVE: To determine the in vitro activity of a polyhexanide-betaine solution against collection strains and multidrug-resistant (MDR) nosocomial isolates, including high-risk clones. METHODS: We studied of 8 ATCC and 21 MDR clinical strains of Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, including the multiresistant high-risk clones. The MICs and MBCs of a 0.1% polyhexanide-0.1% betaine solution were determined by microdilution. For each species, strains with the highest MICs were selected for further experiments. The dilution-neutralization test (PrEN 12054) was performed by incubating bacterial inocula of 106CFU/mL for 1min with undiluted 0.1% polyhexanide-betaine solution. The CFUs were counted after neutralization. Growth curves and time-kill curves at concentrations of 0.25, 1, 4, and 8×MIC, were performed. MICs of recovered strains were determined when regrowth was observed in time-kill studies after 24h of incubation. Strains with reduced susceptibility were selected by serial passage on plates with increasing concentrations of polyhexanide-betaine, and MICs were determined. RESULTS: Polyhexanide-betaine MIC range was 0.5-8mg/L. MBCs equalled or were 1 dilution higher than MICs. The dilution-neutralization method showed total inoculum clearance of all strains. In time-kill curves, no regrowth was observed at 4×MIC, except for S. aureus (8×MIC). Increased MICs were not observed in time-kill curves, or after serial passages after exposure to polyhexanide-betaine. CONCLUSIONS: Polyhexanide-betaine presented bactericidal activity against all MDR clinical isolates tested, including high-risk clones, at significantly lower concentrations and time of activity than those commercially used.

The efficacy and stability of five sanitizing agents challenged with reference microorganisms and clean area isolates / Eficácia e estabilidade de cinco agentes sanitizantes avaliados frente a microrganismos de referência e isolados de áreas limpas

The antimicrobial activity of five sanitizing agents employed in clean areas designated for the pharmaceutical manufacturing of sterile products was tested against nine microorganisms, including four microorganisms from the clean area microbiota. The method consisted of challenging 5 mL of each sanitizing agent - 70% isopropyl alcohol, 0.4% LPH®, 1.16% hydrogen peroxide, 4% hydrogen peroxide, 1% Bioper® and 5% phenol - with 0.1mL each of concentrated suspensions (105 ? 106 CFU/mL) of Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. and Bacillus sp. for 10 minutes, followed by serial dilutions and plating. The results demonstrated that the five agents were effective against S. aureus, C. albicans, Corynebacterium sp., and M. luteus. The same was true of E. coli, except that isopropyl alcohol showed low levels of inactivation. With A. niger, isopropyl alcohol, 0.4% LPH® and hydrogen peroxide were more effective and 5% phenol and 1% Bioper® less effective. 1% Bioper® and 4% hydrogen peroxide showed greater inactivation of Staphylococcus sp., Bacillus sp. and B. subtilis than the other agents. Against S. aureus, C. albicans, Corynebacterium sp. and M. luteus, 5% phenol showed similar activity to other agents, while with A. niger, B. subtilis, Staphylococcus sp. and Bacillus sp., it was similar to or less active than the other agents. It was demonstrated that two microorganisms from the clean area microbiota, Staphylococcus sp. and Bacillus sp., were the most difficult to eradicate, requiring more frequent application of hydrogen peroxide and 1% Bioper® than the other strains.

O objetivo deste estudo é avaliar a atividade antimicrobiana de cinco agentes sanitizantes empregados em áreas limpas construídas para a fabricação de produtos farmacêuticos estéreis contra nove microrganismos, incluindo quatro microrganismos oriundos da área limpa. A metodologia constituiu em desafiar 5 mL de cada agente sanitizante, álcool isopropílico 70%, LPH® 0,400%, peróxido de hidrogênio 1,160% e 4%, Bioper® 1% e fenol 5% com 0,1 mL de suspensão concentrada (105 ? 106 UFC/mL) de Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. e Bacillus sp. individualmente por 10 minutos, seguido de diluições seriadas e plaqueamento. Os resultados demonstraram que os cinco agentes sanitizantes foram efetivos contra S. aureus, C. albicans, Corynebacterium sp., e M. luteus. Os mesmos resultados foram observados com E. coli, exceto para o álcool isopropílico, que demonstrou baixos níveis de inativação. Contra A. niger, álcool isopropílico, 0.4% LPH® e peróxido de hidrogênio foram mais efetivos e fenol e Bioper® menos efetivos. Bioper® e peróxido de hidrogênio 4% demonstraram altos níveis de inativação de Staphylococcus sp., Bacillus sp. e B. subtilis quando comparados com outros agentes. Fenol demonstrou atividade antimicrobiana similar aos outros agentes contra S. aureus, C. albicans, Corynebacterium sp. e M. luteus. Contra A. niger, B. subtilis, Staphylococcus sp. e Bacillus sp., a atividade antimicrobiana do fenol foi similar ou inferior a dos outros agentes. Foi demonstrado que os microrganismos isolados da área limpa, Staphylococcus sp. e Bacillus sp., foram os que apresentaram maior dificuldade para inativar, sendo necessária a aplicação de peróxido de hidrogênio e Bioper® , com maior frequência.