Janaína Santos Nascimento

Bacteriocins as alternative agents for control of multiresistant staphylococcal strains

Aims:  To investigate the activity of seven staphylococcins, bacteriocins produced by staphylococci, against multiresistant Staphylococcus aureus and coagulase‐negative staphylococci (CNS) involved in human infections.

Phenotypic and genetic characterisation of bacteriocin-producing strains of Staphylococcus aureus involved in bovine mastitis.

Fifty strains of Staphylococcus spp. isolated from bovine mastitis cases in several herds from different Argentinian provinces were screened for antimicrobial substances. Twelve strains exhibited a high antagonistic activity against the indicator strain (Corynebacterium fimi) and were chosen for further characterisation. The antimicrobial substances were sensitive to proteolytic enzymes suggesting that they might be bacteriocins (Bac). These strains were identified as S. aureus by the amplification of the femA gene. Plasmid profile analysis of these strains revealed the presence of at least one plasmid. Eleven strains carried a plasmid with a size similar to that of pRJ6 (8.0kb), which encodes aureocin A70, a bacteriocin produced by the Brazilian S. aureus strain A70 isolated from commercial milk. The other strain harboured a much larger plasmid. PCR experiments, using specific primers for amplification of the bacteriocin operon found in pRJ6, showed that all strains had the expected 525bp amplicon, suggesting that the bacteriocin produced may be related to aureocin A70. The genomic DNA of all Bac(+) strains was then analysed by pulsed-field gel electrophoresis (PFGE) in order to investigate clonal relationships amongst strains. Based on the results of PFGE experiments, 10 out of the 12 Bac(+) strains belonged to the same clone. The remaining two strains are possibly related to the prevalent clone. The aureocin A70 producer-strain belonged to a distinct clone.

Bacteriocin production by Staphylococcus aureus involved in bovine mastitis in Brazil

In the present study, 257 Staphylococcus spp. strains were isolated from bovine mastitis cases in 56 different Brazilian dairy herds located in the southeast region of the country and tested for antimicrobial substance (AMS) production. Forty-six strains (17.9%) exhibited AMS production and their identification as Staphylococcus aureus was based on the presence of Gram-positive cocci and on positive results in tests for the ability to coagulate rabbit plasma, to ferment mannitol, and to produce acetoin. The AMS were characterized as bacteriocins (Bac) by their sensitivity to proteolytic enzymes. The Bac(+) strains were tested for resistance to 14 antimicrobial agents showing different profiles. Eighteen strains (39.0%) expressed a multiple antibiotic resistance phenotype. Forty-five strains exhibited at least one plasmid DNA. Cross-immunity analysis against strain S. aureus A70, which produces aureocin A70, amplification of the aurABCD operon (which encodes aureocin A70) or detection of this same operon by DNA/DNA hybridization revealed that 34 strains produce bacteriocins either identical or similar to aureocin A70. The remaining 12 Bac(+) strains produce antimicrobial peptides that seem to be distinct from the best characterized staphylococcal bacteriocins described thus far. The bacteriocin produced by strain 4185 may possess potential practical applications, since it was able to inhibit important pathogens such as Bacillus cereus, Listeria monocytogenes, and Staphylococcus spp. isolated from nosocomial infections.

Genes Involved in Immunity to and Secretion of Aureocin A53, an Atypical Class II Bacteriocin Produced by Staphylococcus aureus A53

Aureocin A53 is an antimicrobial peptide produced by Staphylococcus aureus A53. The genetic determinants involved in aureocin A53 production and immunity to its action are organized in at least four transcriptional units encoded by the 10.4-kb plasmid pRJ9. One transcriptional unit carries only the bacteriocin structural gene, aucA. No immunity gene is found downstream of aucA, as part of the same transcriptional unit. Further downstream of aucA is found an operon which contains the three genes aucEFG, whose products seem to associate to form a dedicated ABC transporter. When aucEFG were expressed in RN4220, an aureocin A53-sensitive S. aureus strain, this strain became partially resistant to the bacteriocin. A gene disruption mutant in aucE was defective in aureocin A53 externalization and more sensitive to aureocin A53 than the wild-type strain, showing that aucEFG are involved in immunity to aureocin A53 by active extrusion of the bacteriocin. Full resistance to aureocin A53 was exhibited by transformants carrying, besides aucEFG, the operon formed by two genes, aucIB and aucIA, located between aucA and aucEFG and carried in the opposite strand. AucIA and AucIB share similarities with hypothetical proteins not found in the gene clusters of other bacteriocins. A gene disruption mutant in orf8, located upstream of aucA and whose product exhibits about 50% similarity to a number of hypothetical membrane proteins found in many Gram-positive bacteria, was strongly affected in aureocin A53 externalization but resistant to aureocin A53, suggesting that Orf8 is also involved in aureocin A53 secretion.

Aureocins 4185, Bacteriocins Produced by Staphylococcus aureus 4185: Potential Application in Food Preservation

In the present study, the bacteriocins produced by Staphylococcus aureus 4185, a strain isolated from bovine mastitis, were purified and partially characterized. After purification by ammonium sulfate precipitation, cation-exchange chromatography, and five runs of high-performance liquid chromatography (HPLC), antimicrobial activity was recovered with 40% and 80% isopropanol, suggesting that more than one antimicrobial peptide, named aureocins 4185, is produced by S. aureus 4185. Mass spectrometry analyses revealed three peptides eluted with 40% isopropanol: peptide A (2,305.3 +/-1.5 Da), peptide B (2,327.3 +/-1.5 Da), and peptide C (3,005.5 +/-1.5 Da), and two peptides eluted with 80% isopropanol: peptide D (6,413.5 +/-1.5 Da) and peptide E (12,834.5 +/-1.5 Da). Although five peptides have been detected, only four small peptide sequences were obtained by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF)/TOF mass spectrometry analyses: SLLEQFTGK (eluted with 40% isopropanol), ALLYDER, NNTSHNLPLGWFNVK, and NNLAQGTFNATK (eluted with 80% isopropanol). The sequences SLLEQFTGK and ALLYDER revealed identity with hypothetical peptides with unknown function. The sequences NNTSHNLPLGWFNVK and NNLAQGTFNATK showed similarity to a segment of a precursor of staphylococcal autolysins. The antimicrobial activity detected in the supernatant of strain 4185 proved to be resistant to heat treatment at 65°C; however, treatment at 80°C abolished completely its antimicrobial properties. The concentrated supernatant containing aureocins 4185 exhibited a strong bacteriolytic activity toward Micrococcus luteus ATCC 4698. Additionally, aureocins 4185 exhibited antagonistic activity against important foodborne pathogens, including Listeria monocytogenes, thus showing a potential application in food preservation.

Antimicrobial Substances Produced by Coliform Strains Active Against Foodborne Pathogens

In the present study, 31 coliform strains were isolated from salad, cheese, and meat products sold in commercial establishments in Rio de Janeiro city, and were tested for antibiotic resistance and antimicrobial substance production. Thirteen strains (41.9%) were resistant to at least one antibiotic tested, among which one presented resistance to nine different antibiotics. Two strains (6.4%) exhibited inhibitory activity against the indicator strains, Escherichia coli LMIFRJ and Salmonella enterica I. The antimicrobial substances that they produced were sensitive to proteolytic enzymes, suggesting that they might be bacteriocins. The producer strains were identified as Klebsiella ozaenae and Raoultella terrigena. Although they had similar spectrums of action, the bacteriocins were shown to be different. Both of them were able to inhibit E. coli, Klebsiella, Enterobacter, and Salmonella strains, including antibiotic-resistant ones. Our results suggest that these bacteriocins, named klebicin K and raoultellin L, could have potential use against some foodborne pathogens.

PREVALÊNCIA E FATORES ASSOCIADOS A QUEDAS EM IDOSOS

Esta pesquisa objetivou determinar a prevalencia de quedas, nos ultimos 12 meses, entre os idosos; comparar as variaveis sociodemograficas, clinicas, de saude e funcionais entre os idosos que tiveram quedas e aqueles que nao as tiveram; e verificar os fatores associados a quedas em idosos. Inquerito domiciliar conduzido com 729 idosos da zona urbana de Uberaba, Minas Gerais. A prevalencia de quedas foi de 28,3%. A maior proporcao entre os idosos que tiveram queda foi a do sexo feminino; com 80 anos ou mais; que apresentavam duas ou mais morbidades e usavam cinco ou mais medicamentos. As quedas estavam associadas ao sexo feminino; com idade de 80 anos ou mais e que apresentavam duas ou mais morbidades. O estudo reforca a necessidade de investimento na promocao da saude e prevencao de morbidades, considerando que, dentre os preditores de quedas, somente a presenca de comordidades e passivel de intervencao do profissional de saude.This research aimed to determine the prevalence of falls in the last 12 months among the elderly; compare sociodemographic, clinical, and functional health variables between the elderly victims and non-victims of falls and verify the factors associated with falls in the elderly. This is a domestic survey conducted with 729 elderly people living in the urban area of the city of Uberaba-MG. The prevalence of falls was 28.3%. Most of the elderly fall victims were female; aged 80 years or older; presence of two or more conditions and used five or more medications. The falls were associated with females; aged 80 years or older and presence of two or more conditions. The study reinforces the need for investment in health promotion and prevention of morbidities, considering that, among the predictors of falls, health professionals can only intervene in the presence of comorbidities.

Qualidade de vida e autoestima de idosos na comunidade

This study sought to investigate the association between the scores for quality of life (QoL) and self-esteem among the elderly in an urban community. A cross-sectional, quantitative and analytical household survey was conducted with 1,691 elderly persons resident in an urban area in a county in Minas Gerais state. The World Health Organization Quality of Life BREF (WHOQOL-BREF), the World Health Organization Quality of Life OLD (WHOQOL-OLD) questionnaires and the Rosenberg Self-Esteem Scale were used in this study. A descriptive statistical analysis and a linear regression model (p < 0.05) were conducted. The results revealed that the social relationships domain (71.19) and the topic of death and dying (74.30) had the highest mean scores among the elderly; while the lowest mean scores were the environment domain (60.39) and the topic of social participation (63.06). The self-esteem scores showed an average of 9.36 ± 4.09. Associations were evident for the lower scores of quality of life in all the WHOQOL-BREF domains and WHOQOL-OLD aspects (except death and dying) with lower levels of self-esteem (p <0.001). The results provide data that contribute to a better understanding of the aspects that influence the QoL of the elderly due to reduced self-esteem, thus providing information for the development of health strategies.This study sought to investigate the association between the scores for quality of life (QoL) and self-esteem among the elderly in an urban community. A cross-sectional, quantitative and analytical household survey was conducted with 1,691 elderly persons resident in an urban area in a county in Minas Gerais state. The World Health Organization Quality of Life BREF (WHOQOL-BREF), the World Health Organization Quality of Life OLD (WHOQOL-OLD) questionnaires and the Rosenberg Self-Esteem Scale were used in this study. A descriptive statistical analysis and a linear regression model (p < 0.05) were conducted. The results revealed that the social relationships domain (71.19) and the topic of death and dying (74.30) had the highest mean scores among the elderly; while the lowest mean scores were the environment domain (60.39) and the topic of social participation (63.06). The self-esteem scores showed an average of 9.36 ± 4.09. Associations were evident for the lower scores of quality of life in all the WHOQOL-BREF domains and WHOQOL-OLD aspects (except death and dying) with lower levels of self-esteem (p <0.001). The results provide data that contribute to a better understanding of the aspects that influence the QoL of the elderly due to reduced self-esteem, thus providing information for the development of health strategies.

PREVALENCE AND FACTORS ASSOCIATED WITH FALLS IN THE ELDERLY

Esta pesquisa objetivou determinar a prevalencia de quedas, nos ultimos 12 meses, entre os idosos; comparar as variaveis sociodemograficas, clinicas, de saude e funcionais entre os idosos que tiveram quedas e aqueles que nao as tiveram; e verificar os fatores associados a quedas em idosos. Inquerito domiciliar conduzido com 729 idosos da zona urbana de Uberaba, Minas Gerais. A prevalencia de quedas foi de 28,3%. A maior proporcao entre os idosos que tiveram queda foi a do sexo feminino; com 80 anos ou mais; que apresentavam duas ou mais morbidades e usavam cinco ou mais medicamentos. As quedas estavam associadas ao sexo feminino; com idade de 80 anos ou mais e que apresentavam duas ou mais morbidades. O estudo reforca a necessidade de investimento na promocao da saude e prevencao de morbidades, considerando que, dentre os preditores de quedas, somente a presenca de comordidades e passivel de intervencao do profissional de saude.This research aimed to determine the prevalence of falls in the last 12 months among the elderly; compare sociodemographic, clinical, and functional health variables between the elderly victims and non-victims of falls and verify the factors associated with falls in the elderly. This is a domestic survey conducted with 729 elderly people living in the urban area of the city of Uberaba-MG. The prevalence of falls was 28.3%. Most of the elderly fall victims were female; aged 80 years or older; presence of two or more conditions and used five or more medications. The falls were associated with females; aged 80 years or older and presence of two or more conditions. The study reinforces the need for investment in health promotion and prevention of morbidities, considering that, among the predictors of falls, health professionals can only intervene in the presence of comorbidities.

Correlation of quality of life with knowledge and attitude of diabetic elderly

OBJECTIVE To describe the quality of life (QL), knowledge and attitude of the elderly with diabetes mellitus (DM) and to correlate the QL with the knowledge and the attitude of the elderly. METHOD It is a cross-sectional study of household inquiry type and developed with 296 elderly with DM. The used instruments were: World Health Organization Quality of Life Bref (WHOQOL-BREF), World Health Organization Quality of Life Old (WHOQOL-OLD), Diabetes Knowledge Scale Questionnaire (DKN-A) and Diabetes Attitudes Questionnaire (ATT-19). RESULTS The female were predominant (68.2%), aged from 70 - 79 years old (43.9%), married or living with a partner (41.6%), living with their children (43.2%), with income of one minimum wage (52.4%), had 4 - 7 years of education (32.8%), on diet use and oral hypoglycemic (68.6%) and less than five years diagnosis (29.1%). The greater the knowledge and the attitude the higher QL scores in physical, psychological, social relationships and environment domains; and facets of sensory works, autonomy, and intimacy. CONCLUSION Educational activities need to be worked improving the knowledge and attitude of the elderly about the DM.To describe the quality of life (QL), knowledge and attitude of the elderly with diabetes mellitus (DM) and to correlate the QL with the knowledge and the attitude of the elderly.It is a cross-sectional study of household inquiry type and developed with 296 elderly with DM. The used instruments were: World Health Organization Quality of Life Bref (WHOQOL-BREF), World Health Organization Quality of Life Old (WHOQOL-OLD), Diabetes Knowledge Scale Questionnaire (DKN-A) and Diabetes Attitudes Questionnaire (ATT-19).The female were predominant (68.2%), aged from 70 - 79 years old (43.9%), married or living with a partner (41.6%), living with their children (43.2%), with income of one minimum wage (52.4%), had 4 - 7 years of education (32.8%), on diet use and oral hypoglycemic (68.6%) and less than five years diagnosis (29.1%). The greater the knowledge and the attitude the higher QL scores in physical, psychological, social relationships and environment domains; and facets of sensory works, autonomy, and intimacy.Educational activities need to be worked improving the knowledge and attitude of the elderly about the DM.