Antibacterial Effect of Hypochlorous Acid on Bacteria Associated with the Formation of Periodontal Biofilms: An in vitro Pilot Study

ABSTRACT Objective: To evaluate the antibacterial effect of electrolytically generated hypochlorous acid on Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis. Material and Methods: In this in vitro experiment, the effect of hypochlorous acid (HOCl) on the strains S. gordonii, F. nucleatum, and P. gingivalis was evaluated using 4% sodium hypochlorite, 0.12% chlorhexidine, and distilled water as controls. The four groups were placed on each plate, and each group was replicated five times. The agar diffusion method by zones measurement was used. The data were processed with SPSS using the Kruskal-Wallis test and multiple comparison tests. Results: Hypochlorous acid showed an average inhibition halo of 9.28 mm on S. gordonii. As expected with distilled water, no zone of inhibition was noted for any of the bacteria, nor were zones of inhibition observed with HOCl for F. nucleatum and P. gingivalis. Conclusion: Hypochlorous acid showed antimicrobial properties against only S. gordonii and was less effective than 4% sodium hypochlorite and 0.12% chlorhexidine, although no significant differences were found between the latter.

Antibiotic Prescription in Endodontics: A Transversal Observational Study Comparing Dental Students and General Dental Practitioners in Rio de Janeiro, Brazil

ABSTRACT Objective: To evaluate and compare antibiotic prescriptions for endodontic infections of last-year undergraduate Dentistry students and dental surgeons from Brazil. Material and Methods: A questionnaire comprised of 15 questions was applied, including a series of hypothetical clinical cases through multiple choice questions. The survey respondents had the option to respond in favor or against the prescription of antimicrobials in each case. Afterwards, the commented answer keys of all topics contained in the survey form were released for educational purpose. Results: A total of 42 undergraduates and 115 dental surgeons answered the survey. Regarding the questions about antimicrobial prescriptions, 91.3% of the professional dentists and 69.8% of the dentistry students indicated that they prescribe antibiotics for a limited number of patients. However, when they responded about drug recommendations, most professionals (76.5%) and students (76.7%) chose to recommend antimicrobials without any clinical recommendation. Conclusion: In the groups herein evaluated, many antibiotic prescriptions could have been avoided. The rational use of these drugs is still a conduct that needs further disclosure and commitment among prescribers.

Creating Antibacterial Properties in Flowable Dental Composites by Incorporation of 3, 4-dihydropyrimidin-2(1H)-ones

ABSTRACT Objective: To investigate the antibacterial, mechanical, physical properties and water sorption of flowable dental composites containing 3,4-dihydropyrimidin-2(1H)-ones. Material and Methods: 3,4-dihydropyrimidin-2(1H)-ones was synthesized and the antibacterial activity of flowable dental composites containing 0-5 wt% 3,4-dihydropyrimidin-2(1H)-ones and also of their mechanical and physical properties on flowable dental composites were investigated. Flexural strength was measured by a three-point bending test. Compressive strength (CS), Water sorption (WS) and depth of cure (DOC) were investigated. The data were analyzed by One-way ANOVA test. The level of significance was determined as p<0.01. Results: The direct contact test demonstrates that by increasing the 3,4-dihydropyrimidin-2(1H)-ones content, the bacterial growth is significantly diminished (p<0.001). The average flexural strength results show that with increasing 3,4-dihydropyrimidin-2(1H)-ones until 3% in the composite, no significant difference was observed in flexural strength (p>0.001) and the mean of compressive strength results show no significant difference between 0-4% groups (p>0.001). The mean of water sorption and depth of cure results shows no significant difference between groups (p>0.001). Conclusion: Incorporation of 3,4-dihydropyrimidin-2(1H)-ones into flowable resin composites in 3% wt can reduce the activity of Streptococcus mutans.

Extratos glicólicos de Pfaffia paniculata K E Juglans regia L: avaliação do potencial antimicrobiano, anti-inflamatório, citotóxico e genotóxico / Glycolic extracts of Pfaffia paniculata K and Juglans regia L: evaluation of antimicrobial, anti-inflammatory, cytotoxic and genotoxic potential

A resistência antimicrobiana atingiu proporções alarmantes em todo o mundo, sendo que na Europa mortes causadas por micro-organismos multirresistentes superam os índices de mortalidade da AIDS, tuberculose e a gripe. Assim a fitoterapia desponta no combate a esta problemática, com as diversas atividades biológicas de plantas e seus derivados. Portanto os objetivos do presente estudo foram avaliar a ação antimicrobiana, anti-inflamatória, citotoxicidade, genotoxicidade e constituição fitoquímica dos extratos glicólicos de P. paniculata e J. regia. A ação sobre bactérias anaeróbias (Porphyromonas gingivalis, P. endodontalis, Parvimonas micra e Fusobacterium nucleatum) foi realizada por meio dos testes de microdiluição em caldo (Protocolo M11-A8 - CLSI) e sobre biofilmes monotípicos. Já a ação sobre aeróbios foi realizada sobre 3 cepas de Klebsiella pneumoniae multirresistente, com testes sobre culturas planctônicas (Protocolo M7-A9) e biofilmes; Foi realizada a verificação da atividade antimicrobiana sobre biofilmes heterotípicos de Candida albicans associada a Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans ou Pseudomonas aeruginosa. A citotoxicidade e a genotoxicdade dos extratos foram avaliadas sobre macrófagos de camundongos (RAW 264.7) e queratinócitos humanos (HaCat) pelos testes de MTT e micronúcleos, respectivamente. O potencial antiinflamatório foi verificado dosando os níveis de TNF-⍺, IL-10 e IL-1ß pelo teste de ELISA. Os dados obtiveram distribuição normal sendo a análise estatística realizada por ANOVA e Tukey (p<0,05%). Os extratos de P. paniculata e J. regia promoveram CMM de 50 mg/mL para as anaeróbias. Os biofilmes de P. gingivalis e P. micra foram eliminados com 100 e 200 mg/mL dos extratos (5 min) e com as concentrações de 50 e 100 mg/mL por 24 h; F. nucleatum e P. endodontalis obtiveram reduções variando de 80 a 90%. Os biofilmes heterotípicos de C. albicans e S. mutans obtiveram reduções de até 80% após contato por 5 min. com J. regia e 71% para P. paniculata. Os biofilmes multirresistentes de K. pneumoniae obtiveram reduções na atividade metabólica de até 67,9%. P. paniculata promoveu viabilidade celular variando de 61,1% a 133,8% sobre queratinócitos humanos após 24 h de contato com as concentrações de 12,5 a 0,39 mg/mL, enquanto J. regia obteve 43,9 a 128,4% de viabilidade. Os macrófagos de camundongo obtiveram viabilidade de 18,1 a 101,9% com P. paniculata e 35,4 a 60,6% para J. regia. P. paniculata promoveu a redução nos níveis da citocina pró-inflamatória IL-1ß e aumento nos níveis da citocina antiinflamatória IL-10. Já J. regia promoveu a redução da citocina pró-inflamatória TNF-⍺. Ambos os extratos não promoveram genotoxicidade frente as linhagens celulares. A análise fitoquímica evidenciou a presença de benzofenonas e ácido cafeoilquínico nos extratos de P. paniculata e J. regia, respectivamente. Em conclusão, os extratos de P. paniculata e J. regia demonstraram ação antimicrobiana sobre bactérias aeróbias e anaeróbias e multirresistentes com destaque a eliminação dos biofilmes de P. gingivalis, P. endodontalis, P. micra e K. pneumoniae (multirresistentes). Os extratos demonstraram a ausência de toxicidade e genotoxicidade conforme tempo de aplicação e concentração utilizada, além de possuírem potencial anti-inflamatório(AU)

Antimicrobial resistance has reached alarming proportions worldwide, with deaths in Europe caused by multi-resistant microorganisms exceeding the mortality rates from AIDS, tuberculosis and influenza. Thus phytotherapy emerges in the fight against this problem, with the various biological activities of plants and their derivatives. Therefore, the objectives of the present study were to evaluate the antimicrobial, antiinflammatory, cytotoxicity, genotoxicity and phytochemical constitution of the glycolic extracts of P. paniculata and J. regia. The action on anaerobic bacteria (Porphyromonas gingivalis, P. endodontalis, Parvimonas micra and Fusobacterium nucleatum) was carried out by means of broth microdilution tests (Protocol M11-A8 - CLSI) and on monotypic biofilms. The action on aerobes was performed on 3 strains of multi-resistant Klebsiella pneumoniae, with tests on planktonic cultures (Protocol M7-A9) and biofilms; The verification of antimicrobial activity on heterotypic biofilms of Candida albicans associated with Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans or Pseudomonas aeruginosa was also performed. The cytotoxicity and genotoxicity of the extracts were evaluated on mouse macrophages (RAW 264.7) and human keratinocytes (HaCat) by MTT and micronucleus tests, respectively. The anti-inflammatory potential was assessed by the ELISA test, TNF-⍺, IL-10 and IL-1ß levels were measured. The data obtained a normal distribution and the statistical analysis was performed by ANOVA and Tukey (p <0.05%). The extracts of P. paniculata and J. regia promoted CMM of 50 mg / mL for anaerobes. The biofilms of P. gingivalis and P. micra were eradicated with 100 and 200 mg / mL of the extracts (5 min) and with the concentrations of 50 and 100 mg / mL (24 hours); F. nucleatum and P. endodontalis obtained reductions ranging from 80 to 90%. The heterotypic biofilms of C. albicans and S. mutans obtained reductions of up to 80% after contact for 5 minutes with J. regia and 71% for P. paniculata. The multidrug-resistant strains of K. pneumoniae obtained reductions in metabolic activity of up to 67.9%. The P. paniculata extract promoted cell viability ranging from 61.1% to 133.8% on human keratinocytes after 24 h of contact with concentrations of 12.5 to 0.39 mg / mL, while J. regia obtained 43, 9 to 128.4% viability. Mouse macrophages obtained viability from 18.1 to 101.9% with P. paniculata and 35.4 to 60.6% for J. regia. P. paniculata promoted a reduction in the levels of the pro-inflammatory cytokine IL-1ß and an increase in the levels of the anti-inflammatory cytokine IL-10. J. regia promoted the reduction of the pro-inflammatory cytokine TNF-⍺. Both extracts did not promote genotoxicity against cell lines. Phytochemical analysis showed the presence of benzophenones and caffeoylquinic acid in the extracts of P. paniculata and J. regia, respectively. In conclusion, the extracts of P. paniculata and J. regia demonstrated antimicrobial action on aerobic and anaerobic and multiresistant bacteria, with emphasis on the elimination of the biofilms of P. gingivalis, P. endodontalis and P. micra, as well as the reductions of the biofilms of K. pneumoniae multidrug-resistant. The extracts demonstrated the absence of toxicity and genotoxicity according to the time of application and concentration used, in addition to having anti-inflammatory potential(AU)

In Vitro Evaluation of the Antibacterial Effect of Photodynamic Therapy with Methylene Blue

Abstract Objective: To evaluate, in vitro, the effect of photodynamic therapy (PDT) compared to laser therapy and the use of a photosensitizer alone. Material and Methods: The following therapies were used: PDT, laser therapy and photosensitizer alone. For PDT, methylene blue (MB) at different concentrations and red laser InGaAlP 660nm were used. For the use of low-power laser (LPL) alone, red laser InGaAlP 660 nm and infrared laser AsGaAl, 830 nm, both in continuous emission were used. Standard ATCC strains of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) species were used. The antibacterial effect of PDT was quantified by the diameter of the inhibition halos. Results: PDT (LPL 660 nm, 320 J/cm2) with MB at concentration of 50 µg/mL showed antibacterial efficacy only when tested against S. aureus and E. coli strains, as well as with the isolated use of MB at the same concentration. Using LPL alone, whether red or infrared, with different dosimetry, no antibacterial effect was observed. In none of the therapeutic modalities used, P. aeruginosa inactivation was observed. Conclusion: Antibacterial effects of PDT (LPL 660 nm + MB 50 µg/mL) were observed for S. aureus and E. coli, as well as with the isolated use of MB (50 µg/mL). For P. aeruginosa, no antibacterial effect with any of the protocols recommended in the study was observed.

Anti-Biofilm and Hemolytic Effects of Cymbopogon citratus (Dc) Stapf Essential Oil

Abstract Objective: To perform chemical analysis and to evaluate the anti-biofilm and hemolytic effect of the essential oil of Cymbopogon citratus. Material and Methods: Gaseous chromatography coupled to mass spectrometer was performed for chemical characterization of the essential oil. To verify the antimicrobial action, the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) were determined. From MIC, MBC and MFC data, concentrations were established to verify the anti-biofilm effect and for the hemolysis test on human erythrocytes. A multispecies biofilm was developed in vitro and mouthwash applications were simulated to determine the inhibition of biofilm formation or its removal. Results were analyzed through ANOVA statistical test, complemented by the Tukey test, considering a significance level of 5% Results: The major component of the essential oil is citral. MIC verified for Streptococcus mutans was 1mg / mL, while for Candida albicans, it was 125 μg/mL, presenting microbicidal effect for both microorganisms tested. The essential oil was able to inhibit biofilm formation (p<0.001), presenting non-toxic hemolysis percentage in concentration below 500 μg/mL Conclusion: The essential oil of Cymbopogon citratus is antimicrobial, antibiofilm and non-toxic to human erythrocytes, representing a natural product with potential for use in Dentistry.

Avaliação in vitro da atividade antimicrobiana dos componentes de um enxaguatório bucal contendo malva / In vitro antimicrobial activity of the components of a mouthwash containing malva sylvestris

Objetivo: Avaliar a atividade antimicrobiana in vitro dos componentes (tirotricina, quinosol e tintura de malva) de um enxaguatório bucal contendo malva (Malvatricin®) sobre Streptococcus mutans, Lactobacillus spp. e um pool de micro-organismos da cavidade bucal. Método: Para a verificação do potencial antimicrobiano do enxaguatório bucal contendo malva (Malvatricin®) e de seus diferentes componentes, a metodologia utilizada foi a da difusão em ágar-cilindro em placas. Utilizaram-se dez placas com ágar Brain Heart Infusion para cada micro-organismo e foram testadas as seguintes soluções: Malvatricin®, tirotricina, quinosol e tintura de malva. Como controle positivo foi utilizada uma solução de clorexidina 0,12%. As placas foram incubadas por 24 horas a 37°C em anaerobiose. Após 24 horas, mensuraram-se os diâmetros das zonas de inibição. Utilizou-se o teste de Kruskal-Wallis, seguido pelo teste de comparações múltiplas, quando indicado, para comparar o efeito de cada substância sobre os micro-organismos testados. O nível de significância adotado foi de 5%. Resultados: Sobre Streptococcus mutans, Lactobacillus e um pool de micro-organismos da cavidade bucal, Malvatricin® apresentou valores de medianas 23,47; 8,61 e 11,23, respectivamente. O quinosol apresentou resultado semelhante ao de Malvatricin®, mostrando-se efetivo para inibir o crescimento microbiano de todos os micro-organismos (27,17; 9,33; 12,53). A tirotricina (0; 5,66; 0) e a tintura de malva (0; 0; 4,29) apresentaram pouca ou nenhuma atividade antimicrobiana. A clorexidina apresentou as maiores zonas de inibição frente a todos os micro-organismos testados (30,06; 15,54; 20,89). Conclusão: Os resultados do presente estudo sugerem que, dentre os componentes presentes na composição do produto comercial Malvatricin®, a substância quinosol apresenta a maior atividade antimicrobiana frente aos micro-organismos testados. E que a atividade antimicrobiana verificada para o produto comercial provavelmente deva-se à ação da substância quinosol, presente em sua composição.

Objective: To evaluate the in vitro antimicrobial activity of the components (tyrothricin, hydroxyquinoline and Malva sylvestris tincture) of a mouthwash containing Malva sylvestris (Malvatricin®) against Streptococcus mutans, Lactobacillus spp. and a pool of oral microorganisms. Method: In order to verify the antimicrobial potential of the Malva sylvestris-containing mouthwash (Malvatricin®) and its different components, was used the cylinder-agar diffusion plate methodology. Ten plates with Brain Heart Infusion agar were used for each microorganism and the following solutions were tested: Malvatricin®, tyrothricin, hydroxyquinoline and Malva sylvestris tincture. The positive control was a 0.12% chlorhexidine solution. The plates were incubated for 24 hours at 37°C in anaerobiosis. After 24 hours, the diameters of bacterial growth inhibition zones were measured. The Kruskal-Wallis test and the multiple-comparisons test (when required) were used to compare the effect of each substance against the test microorganisms. The significance level was set at 5%. Results: Malvatricin® presented medians of 23.47, 8.61 and 11.23, respectively, against Streptococcus mutans, Lactobacillus spp. and a pool of oral microorganisms. Hydroxyquinoline showed similar result to Malvatricin®, being effective to inhibit the growth of all microorganisms (27.17, 9.33 and 12.53, respectively). Tyrothricin (0, 5.66, 0, respectively) and Malva sylvestris tincture (0, 0, 4.29, respectively) showed little or no antimicrobial activity. Chlorhexidine produced the largest inhibition zones against the tested microorganisms (30.06, 15.54, 20.89, respectively). Conclusion: The results from this study suggest that among all components of Malvatricin®, hydroxyquinoline presented the greatest antimicrobial activity against the tested microorganisms, and that the antimicrobial activity of the commercial product is likely due to the action of the hydroxyquinoline present in its composition

Allergy to beta-lactams in pediatrics: a practical approach

OBJETIVO: Apresentar uma abordagem prática ao diagnóstico e conduta na alergia a antibióticos beta-lactâmicos. FONTES DOS DADOS: Periódicos da área de alergia indexados nas bases MEDLINE e LILACS, além de estudos e textos clássicos que tratam do tema. SíNTESE DOS DADOS: A alergia à penicilina é relatada com freqüência, em muitos casos resultando na exclusão desse medicamento do arsenal terapêutico. Cerca de 10 por cento dos relatos de alergia a drogas são confirmados. As manifestações clínicas decorrentes da reação alérgica à penicilina são bastante amplas, destacando-se os quadros cutâneos. Os quatro mecanismos de hipersensibilidade de Gell & Coombs estão envolvidos nas reações alérgicas. A penicilina é degradada em determinante maior (95 por cento dos produtos) e em determinantes menores (5 por cento dos produtos). As reações imediatas, mediadas por IgE, e que determinam quadros de anafilaxia, estão relacionadas aos determinantes menores em 95 por cento dos casos. A hipersensibilidade a esses produtos pode ser avaliada através de testes cutâneos realizados com os determinantes maior e menores, permitindo, assim, evitar o choque anafilático em indivíduos alérgicos. O texto ressalta conhecimentos básicos sobre a alergia à penicilina, propiciando um diagnóstico mais adequado desse evento e a conduta em casos de suspeita de alergia a beta-lactâmicos. CONCLUSÃO: O diagnóstico de alergia à penicilina tem sido feito de forma inadequada, resultando em sua exclusão do arsenal terapêutico. O melhor reconhecimento dessas condições permitirá o uso da penicilina com diminuição dos riscos decorrentes da hipersensibilidade.

OBJECTIVE: To present a practical approach to the diagnosis and management of allergy to beta-lactam antibiotics. SOURCES: Allergy journals indexed in MEDLINE and LILACS, as well as seminal studies and texts. SUMMARY OF THE FINDINGS: Allergy to penicillin is commonly reported. In many cases, this results in the decision not to use this drug. About 10 percent of drug allergy reports are confirmed. The clinical manifestations due to allergic reaction to penicillin vary widely, with emphasis on skin disorders. Gell & Coombs' four hypersensitivity mechanisms are involved in allergic reactions. Penicillin is degraded to a major (95 percent) and minor determinants (5 percent). Immediate IgE-mediated reactions causing anaphylaxis are associated with minor determinants in 95 percent of the cases. Hypersensitivity to these products can be assessed using cutaneous tests performed with major and minor determinants, thus avoiding anaphylactic shock in allergic individuals. The present article underscores the basic body of knowledge on allergy to penicillin, providing support for a more accurate diagnosis of this event and for the choice of management in cases of suspected beta-lactam allergy. CONCLUSIONS: The incorrect diagnosis of penicillin allergy frequently leads to the exclusion of this drug as a therapeutic option. A better recognition of these situations will enable the use of penicillin and reduce the risks associated with hypersensitivity.

Infección relacionada con el drenaje ventricular externo: tratamiento intravenoso versus intratecal, revisión de la literatura / External ventricular drainage infection: intravenous vs intrathecal treatment, Review

Ante la emergencia de infecciones relacionadas al drenaje ventricular externo por gérmenes multirresistentes y la necesidad de utilizar antibióticos cuya acción en el sistema nervioso central es controvertida, surge la necesidad de emplear terapéuticas para la administración de fármacos cuyos beneficios merecen ser evaluados. Se realizó una búsqueda de la literatura en PUBMED y los datos fueron extraídos de estudios publicados entre 1987-2005. En esta revisión de la literatura se analizaron los resultados obtenidos, comparando: el tratamiento endovenoso con el tratamiento intratecal en pacientes con infección asociada a la ventriculostomía, los antibióticos utilizados y su penetración al líquido cefalorraquídeo (LCR) con cada vía. Finalmente, se propuso qué pacientes podrían beneficiarse con cada terapéutica, a pesar de la falta de evidencias claras, sugiriendo la necesidad de realizar un trabajo randomizado prospectivo comparando sus beneficios. Palabras clave: infección, tratamiento, ventriculitis.

Due to the emergency of external ventricular drainage infections, cause by multiresistant bacterial strains, and the need to treat them with antibiotics, whose action in the central nervous system is controversial, arises the terapeutic necessity to administer antibiotics whose benefits should be evaluated. We search the Pubmed library. The data were extracted from published studies between 1987-2005. In this reivision the results were analyzed, comparing envovenous versus intrathecal treatment in patients with a ventriculostomy associated infection, the antibiotics that were used and their cerebrospinal fluid (CSF) levels according to each route. Finally, even though there is a lack of clear evidence, we proposed which patients could benefit with each treatment. We conclude that a randomized prospective study, comparing the benefits of each treatment is needed.

Prospeccion de las resistencias al tratamiento antibiotico en las infecciones urinarias / Prospection of the resistance of the treatment antibiotic in the urinary infection

Hemos podido comprobar que de todos los antibioticos usados, un pequeño grupo de ellos son suficientes para el tratamiento de las infecciones urinarias en general, pero de ellos ninguno por si solo es capaz de cubrir toda la amplia gama de germenes patogenos que producen las infecciones del tracto urinario por eso creemos que es necesario la realizacion del antibiograma y asi emplear el antibiotico mas idoneo, evitando usar terapeutica a ciegas, que no solo no aportara mejoria en la evolucion del proceso, sino que contribuira a crear y aumentar las resistencias ya que gran numero de antibioticos muy empleados en la actualidad tienen un escaso porcentaje de exitos en el tratamiento de estas infecciones

Defensinas: Una nueva perspectiva en antibioterapia / Defensins

Se hace una actualización del avance en la investigación sobre las defensinas, que son moléculas catiónicas, con poder microbicida variable. Estas moléculas se han dividido en dos familias con base en su composición: las alpha y las beta defensinas. Algunas de estas moléculas se han encontrado como constitutivas en muchos tejidos, y otras como las hBD-2, sólo se encuentran cuando hay un proceso infeccioso

In vitro comparison of disk diffusion and agar dilution antibiotic susceptibility test methods for Neisseria gonorrhoeae

At present, most Neisseria gonorrhoeae testing is done with Beta-lactamase and agar dilution tests with common therapeutic agents. Generally, in bacteriological diagnosis laboratories in Argentina, study of antibiotic susceptibility of N. gonorrhoeae is based on Beta-lactamase determination and agar dilution method with common therapeutic agents. The National Committee for Clinical Laboratory Standards (NCCLS) has recently described a disk diffusion test that produces results comparable to the reference agar dilution method for antibiotic susceptibility of N. gonorrhoeae, using a dispersion diagram for analysing the correlation between both techniques. We obtained 57 gonococcal isolates from patients attending a clinic for sexually transmitted diseases in Tucuman, Argentina. Antibiotic susceptibility tests using agar dilution and disk diffusion techniques were compared. The established NCCLS interpretive criteria for both susceptibility methods appeared to be applicable to domestic gonococcal strains. The correlation between the MIC's and the zones of inhibition was studied for penicillin, ampicillin, cefoxitin, spectinomycin, cefotaxime, cephaloridine, cephalexin, tetracycline, norfloxacin and kanamycin. Dispersion diagrams showed a high correlation between both methods.

Efecto antibiótico de cepas silvestres de Streptomyces aisladas de suelos chilenos / Antimicrobial effect of wild Streptomyces strains isolated from chilean soils

Background: the solts of the southern part of Chile, that are isolated, cold, humid, poorly axygenated and with a low acitity, could contain new strains of antimicrobial producing Streptomyces strains with antimicrobial activity towards pathogenic bacteria and fungi. Material and methods: two hundred fifty eight soil and sediment samples were collected from 148 paces in Souther regions of Chile. They were cultured in Kuster-Williams growth media and the presence of Streptomyces was confirmed by microscopic examination and biochemical characterization. The antimicrobial activity against reference microorganisms. Results: Seventy seven percent of soils were positive and 542 wild strains of Streptomyces were isolates; of these, 266 had antimicrobial activity. Fifty three percent of isolates had activity against S aureus 43 percent against B subtilis and 0.7 percent against E coli. Most Streptomyces were active against more than one organism. When there was activity against single organisms, these were mostly eucariotic, such as C albicans and T mentagrophytes. Among clinical microorganisms, 29 percent of S aureus strains were inhibited, while P aeruginosa, Alternaria sp, P vulgaris and Y enterocolitica strains were not inhibited. The most frequent Streptomyces morphotypes were those showing pigmented colonies with flexuous and spiral shaped chains of arthopores. Conclusions: soils of the southern region Chile allow the grouth of abundant native strains of Streptomyces with a promising anticrobial activity

Desensibilización a los antimicrobianos / Desensitisation of antimicrobial allergic patients

Se comunica una opción para valorar y tomar experiencia en el comportamiento de las moléculas que se manifiestan bioquímicamente como haptenos. Se explica el porqué de la aplicación práctica de la dilución del medicamento que desencadena la alergia cuando se utiliza como antígeno para prueba cutánea. Se menciona, en una forma ordenada, cómo sistematizar la aplicación del medicamento que produce la alergia. El método de medición del riesgo-beneficio es seguro, práctico y de actualidad fisiológica y bioquímica

Resistencia bacteriana / Bacterial resistence

En la medida en que contamos con más y mejores antibioticos, las bacterias se tornan tambien más resistentes a los mismos. El mal uso o errada indicacion de los antimicrobianos han conducido a que este fenomeno se evidencie en forma critica. Los mecanismos de resistencia para diversos medicamentos, se presentan en esta revision.

Effects of antibiotics on the production of bacteria specific immunoglobulins in cases of acute otitis media

In this study, 130 children with acute otitis media were examined and subjected to myringotomy and aspiration of middle ear fluid. Only 50 patients could attend accurately at the follow up. Middle ear aspirates were cultured. Sera were collected from patients at days 0, 7 and 14 examined by indirect immunofluorescent technique for specific 1gG and 1gM against the causative organism. After myringotomy, patients were divided into two groups. Group A, received Velosef 75 mg /kg/day orally in 4 divided doses for 1 w. Group B, received the same antibiotic, but starting 3 days after myringotomy. Follow up by tympanometry and audiometry was done after 2 weeks and 1 month. Discharge rapidly stopped in group A [mean 2.24 d.], while in group B stopped 3 days after [mean 3.24 d.]. Effusion persisted in 5 cases of group A and 3 cases of group B. Only 1 case of group A showed rising titer of Ig, while 3 cases of group B did so. So late administration of cephradine is accompanied by more active immune response and more rapid resolution of middle ear effusion