Biofilm-forming microorganisms causing hospital-acquired infections from intravenous catheter: A systematic review.

The high prevalence of nosocomial infections is related to the use of medical insertion devices such as central venous catheters (CVCs). Most of the microorganisms causing nosocomial infections are biofilm producers, this characteristic allows them to adhere to abiotic surfaces and cause initial catheter infections that can lead to bloodstream infections. Our main goal in this systematic review was to evaluate the prevalence of biofilm among CVC-related infections, particularly among Intensive Care Unit (ICU) patients, in the studies applying different in vitro and in vivo methodologies. All studies reporting clinical isolates from patients with catheter-related nosocomial infections and biofilm evaluation published up to 24 June 2022 in the PubMed and Scopus databases were included. Twenty-five studies met the eligibility criteria and were included in this systematic review for analysis. Different methodologies were applied in the assessment of biofilm-forming microorganisms including in vitro assays, catheter-infected in vitro, and in vivo mouse models. The present study showed that between 59 and 100% of clinical isolates were able to form biofilms, and the prevalence rate of biofilm formation varied significantly between studies from different countries and regions. Among the clinical isolates collected in our study set, a wide variety of microorganisms including Gram-positive strains, Gram-negative strains, and Candida albicans were found. Many authors studied resistance mechanisms and genes related to biofilm development and surface adherence properties. In some cases, the studies also evaluated biofilm inhibition assays using various kinds of catheter coatings.

Mechanisms responsible for the hypocholesterolaemic effect of regular consumption of probiotics.

CVD affect a large proportion of the world's population, with dyslipidaemia as the major risk factor. The regular consumption of both probiotic bacteria and yeast has been associated with improvement in the serum lipid profile. Thus, the present review aims to describe and discuss the potential mechanisms responsible for the hypocholesterolaemic effect of regular consumption of probiotic bacteria and yeast. Regarding the hypocholesterolaemic effect of probiotic bacteria, the potential mechanisms responsible include: deconjugation of bile salts; modulation of lipid metabolism; and decreased absorption of intestinal cholesterol through co-precipitation of intestinal cholesterol with the deconjugated bile salts, incorporation and assimilation of cholesterol in the cell membrane of the probiotics, intestinal conversion of cholesterol in coprostanol, and inhibition of the expression of the intestinal cholesterol transporter Niemann-Pick C1 like 1 (NPC1L1) in the enterocytes. The potential mechanisms responsible for the hypocholesterolaemic effect of probiotic yeasts include: deconjugation of bile salts; co-precipitation of intestinal cholesterol with the deconjugated bile salts; incorporation and assimilation of cholesterol in the cell membrane; and inhibition of hepatic cholesterol synthesis. The regular consumption of probiotic bacteria and yeast, as a non-pharmaceutical approach to help manage cardiovascular risk, holds promise, according to the beneficial hypocholesterolaemic effects described herein. However, the hypocholesterolaemic effects vary according to the strains used, the physiological state of the host, and the type of diet to which the probiotics are added. Further studies are necessary to fill the gaps with regard to the knowledge related to this topic.

Number of colony-forming unit-Hill colonies among children and teenagers with obesity, dyslipidemia and breastfeeding history.

BACKGROUND AND AIMS: The number of colony-forming unit (CFU)-Hill colonies has been proposed as a biomarker of vascular function and cardiovascular risk in adults but information about its role in children is scarce. This study evaluates the associations between obesity, cardiovascular risk factors and breastfeeding history with the numbers of CFU-Hill colonies in a sample of young people. METHODS AND RESULTS: We selected 49 children and teenagers between ages 10 and 17 (65.3% boys) from Mexican Health Care system. Physical activity and Anthropometric measures data were registered. CFU-Hill colonies were cultured from mononuclear cells obtained from venous blood. We detected inverse associations between the formation of CFU-Hill colonies and body mass index (BMI; ß = -1.53; 95% confidence interval [CI], -1.92, -1.13), triglycerides (ß = -0.26; 95%CI = -0.34, -0.18), total cholesterol (ß = -0.13; 95%CI = -0.17, -0.08), Low Density Lipoprotein (LDL) (ß = -0.20; 95%CI = -0.31, -0.09) and glucose (ß = -0.37; 95%CI = -0.55, -0.18) using multivariate models. Breastfeeding duration showed a 1.46-colony increase for each month of breastfeeding (95%CI = 0.73, 2.18). CONCLUSIONS: CFU-Hill colony-forming capacity in children and teenagers was inversely associated with obesity, dyslipidemia and high blood levels of glucose. In contrast a longer breastfeeding duration was directly associated with an increased number of CFU-Hill colonies. However these results must be confirmed with further studies. Our findings support the importance of promoting breastfeeding and monitoring nutritional and metabolic status at an early age to prevent chronic disease development.

Lactobacillus acidophilus ATCC 4356 inhibits biofilm formation by C. albicans and attenuates the experimental candidiasis in Galleria mellonella.

Probiotic strains of Lactobacillus have been studied for their inhibitory effects on Candida albicans. However, few studies have investigated the effect of these strains on biofilm formation, filamentation and C. albicans infection. The objective of this study was to evaluate the influence of Lactobacillus acidophilus ATCC 4356 on C. albicans ATCC 18804 using in vitro and in vivo models. In vitro analysis evaluated the effects of L. acidophilus on the biofilm formation and on the capacity of C. albicans filamentation. For in vivo study, Galleria mellonella was used as an infection model to evaluate the effects of L. acidophilus on candidiasis by survival analysis, quantification of C. albicans CFU/mL, and histological analysis. The direct effects of L. acidophilus cells on C. albicans, as well as the indirect effects using only a Lactobacillus culture filtrate, were evaluated in both tests. The in vitro results showed that both L. acidophilus cells and filtrate were able to inhibit C. albicans biofilm formation and filamentation. In the in vivo study, injection of L. acidophilus into G. mellonella larvae infected with C. albicans increased the survival of these animals. Furthermore, the number of C. albicans CFU/mL recovered from the larval hemolymph was lower in the group inoculated with L. acidophilus compared to the control group. In conclusion, L. acidophilus ATCC 4356 inhibited in vitro biofilm formation by C. albicans and protected G. mellonella against experimental candidiasis in vivo.

Protective capacity of proteoliposomes from Mycobacterium bovis BCG in a mouse model of tuberculosis.

Tuberculosis (TB) is one of the most important causes of mortality and morbidity due to infectious diseases. BCG, the vaccine in use, is not fully protective against TB. In a previous study, we have shown that proteoliposomes (outer membrane extracts), obtained from BCG (PLBCG) were able to induce humoral immune responses against Mycobacterium tuberculosis (Mtb) antigens. With the objective to evaluate the protective capability of PLBCG alone or as a booster with BCG, a murine model of progressive pulmonary TB was used. Animals immunized with PLBCG adjuvanted with alum (PLBCG-Al) showed similar protection to that conferred by BCG. The group immunized with PLBCG-Al as a booster to BCG gave superior protection than BCG as evidenced by a reduction of bacterial load in lungs 2 months after infection with Mtb. Animals immunized with BCG, PLBCG-Al and this formulation as a booster of BCG, showed a significant decrease of tissue damage (percentage of pneumonic area/lung) compared with non-immunized animals. These results demonstrate that immunization with PLBCG-Al alone or as a booster to BCG induce appropriate protection against challenge with Mtb in mice and support the future evaluation of PLBCG as a promising vaccine candidate against Mtb.

Avaliação do desempenho da limpeza e desinfecção das máquinas lavadoras desinfectadoras automáticas em programas com diferentes tempos e temperaturas / Evaluation of cleaning and disinfection processes performed by automatic washing machine in programs presenting different time and temperature

A limpeza é, inegavelmente, o núcleo central de todas as atividades relacionadas ao reprocessamento de artigos médico-hospitalares. A lavadora desinfectadora é uma nova tecnologia, que trouxe grandes vantagens, como padronização dos procedimentos de limpeza, documentação do processo e diminuição do risco ocupacional de ordem biológica. Atualmente, existem equipamentos que disponibilizam programas com diferentes tempo e temperatura. Para subsidiar a escolha de programas, propôs-se nesta pesquisa investigar o desempenho das lavadoras desinfectadoras nos distintos programas (Norma Alemã, BGA 94ºC/10 minutos; Norma da Grã-Bretanha, DHSS/HTM 90ºC/1segundo; Norma da Grã-Bretanha, DHSS/HTM 82ºC/2minutos; Norma da Holanda, RIVM 90ºC/5 minutos; Norma da Suécia, SPRI/SIS 85ºC/1minuto; Norma da Suécia, SPRI/SIS 85ºC/3 minutos; ciclo com temperatura 70ºC e tempo 30 minutos para Pasteurização), avaliando-se o desempenho dos testes de limpeza e termodesinfecção em equipamento validado. Conforme as recomendações das Normas ISO 15883-1/1999 e HTM2030 (NHS States,1997), para avaliação do desempenho da limpeza foram utilizados três testes: Soil Test, Biotrace Pro-tect e Test Kit Proteína. Como resultado dos testes do desempenho da limpeza, constatou-se resíduo de sujidade após avaliação com Soil-Test em 1,3% dos instrumentais, do total de 313 avaliados (cinco instrumentais de complexidade crítica, dois deles não desmontáveis-Kerrison e Goiva). Na avaliação de resíduo de proteína com teste Biotrace Pro-tect constatou-se que, dos 65 instrumentais avaliados, 60 (92%) apresentaram resultado satisfatório. Os cinco instrumentais (8%) que apresentaram resíduo de sujidade com Soil-Test, também apresentaram, após avaliação com teste Biotrace Pro-tect, resíduo de proteína. Na avaliação realizada com o Test Kit Proteína, 141(100%) instrumentais apresentaram ausência de proteína. Para avaliação do desempenho da termodesinfecção, ) os instrumentais escolhidos para experimento foram intencionalmente contaminados com sangue humano e em seguida submetidos aos processos de termodesinfecção em diferentes programas. A contagem de UFC dos microrganismos viáveis foi feita antes e após a termodesinfecção, partindo-se da contaminação inicial de 107 e 108 UFC. Quanto aos resultados destes testes, de modo uniforme, todos os ciclos apresentaram desempenho satisfatório de <102 UFC, resultado esse entendido como ausência de crescimento microbiano, considerando-se a diluição empregada. Nos cálculos dos valores da Letalidade Mínima e DAL - Nível de Segurança de Desinfecção, os protocolos aprovados foram: Norma Alemã, BGA 94ºC/10 minutos; Norma da Grã-Bretanha, DHSS/HTM 90ºC/1 segundo; Norma da Holanda, RIVM 90ºC / 5 minutos; Norma da Suécia, SPRI/SIS 85ºC / 1 minuto; Norma da Suécia, SPRI/SIS 85ºC/ 3 minutos. Os protocolos que não alcançaram os valores preconizados da Letalidade Mínima de 10 minutos e DAL =10-2 após validação foram: Norma da Grã-Bretanha, DHSS/HTM 82ºC / 2 minutos; Temperatura 70ºC e Tempo de 30 minutos para Pasteurização. Como conclusão, a presente pesquisa evidenciou desempenhos satisfatórios das Máquinas Lavadoras Desinfectadoras tanto na limpeza mecânica quanto na desinfecção, em todos os programas testados, com diferentes tempos e temperaturas apesar do DAL e A0 de alguns programas terem sido reprovados. Evidenciou que em instrumentais de conformação complexa, especialmente quando não desmontáveis, a remoção completa dos resíduos não ocorre nas máquinas, sugerindo que a limpeza destes seja manual, utilizando-se artefatos adequados.

Cleaning is undeniably the main focus of all activities related to the reprocessing of medical and hospital supplies. The washer-disinfector machine represents a new technology that has brought great advantages as the standardization of the cleaning procedures, the process registering and the reduction of occupational hazards coming from biological sources. Nowadays, there are equipments with programs presenting different time and temperature. In order to subside the choice of programs, this essay aims to investigate the performance of washer-disinfectors in the following different programs (German Federal Health Authority BGA, 94ºC/10 minutes; British Standard DHSS/HTM, 90º C/1 second; British Standard DHSS/HTM, 82º C/2 minutes; The Netherlands RIVM, 90º C/5 minutes; Swedish Standards Institute SPRI/SIS, 85ºC/1 minute; Swedish Standard Institute SPRI/SIS, 85ºC/3minutes; cycle temperature 70ºC and pasteurization time 30 minutes), evaluating the performance of cleaning and thermo disinfection tests in validated equipment. According to recommendations in ISO 15883-1/1999 and HTM 2030 (NHS States, 1997) for evaluating the cleaning and disinfection processes, three tests were performed: Soil Test, Biotrace Pro-tect and Test Kit Protein. As a result of the cleaning tests performance, soiling was found after evaluation with Soil Test performed in 1,3% of the instruments (5 of them presenting critical complexity, 2 of them not dismountable - Kerrison and Rongeur). In 65 instruments evaluated by Biotrace Pro-tect, 60 instruments (92%) presented good results. Five instruments (8%) presented soiling after evaluation with Soil Test, and after Biotrace Pro-tect evaluation presented protein contamination. After the evaluation performed with Test Kit Protein no instrument presented protein contamination (141 instruments, 100%). To evaluate the thermo disinfection performance the instruments chosen for the test were intentionally contaminated with human blood and after that were under thermo disinfection processes in different programs. The counting of possible present microorganisms was done before and after the thermo disinfection process, starting from an initial contamination of 107 and 108 UFC. Concerning the results of these tests, in general all cycles presented a good performance (<102 UFC), which was understood as the absence of microbiological growth, considering the dilution given. To calculate the Minimal Lethality and DAL - Disinfection Assurance Level, the approved protocols were: German Federal Health Authority BGA, 94ºC/10 minutes; British Standard DHSS/HTM, 90ºC/1 second; The Netherlands RIVM, 90ºC/5 minutes; Swedish Standards Institute SPRI/SIS, 85ºC/1 minute and Swedish Standards Institute SPRI/SIS, 85ºC/3 minutes. The protocols that did not reach the professed values for Minimal Lethality of 10 minutes and DAL = 10 -2 after validation were: British Standard DHSS/HTM, 82ºC/2 minutes; temperature 70ºC and pasteurization time 30 minutes. Concluding, this study evidenced the good performance of the washer-disinfector machines for mechanic cleaning as for disinfection in all tested programs with different time and temperature. It also demonstrated that for instruments with complex shape, specially the not dismountable ones, the complete soiling remove do not occur on the machines and suggests that this cleaning requires handicraft employing adequate material.