Síntesis de nanopartículas de ácido poliláctico cargadas con antibióticos y su actividad antibacteriana contra Escherichia coli O157:H7 y Staphylococcus aureus resistente a meticilina / Synthesis of antibiotic loaded polylactic acid nanoparticles and their antibacterial activity against Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus

Resumen Introducción: Las nanopartículas poliméricas constituyen una herramienta nanotecnológica que podría ayudar a combatir los microorganismos patógenos que han desarrollado resistencia a los antibióticos convencionales. Objetivo: Sintetizar nanopartículas de ácido poliláctico cargadas con ofloxacina y vancomicina, y determinar su actividad antibacteriana frente a Escherichia coli O157:H7 y Staphylococcus aureus resistente a la meticilina (SARM). Materiales y métodos: Las nanopartículas de ácido poliláctico cargadas con ofloxacina y vancomicina se sintetizaron utilizando el método de emulsión y evaporación de solvente. Se caracterizaron mediante dispersión de luz en modo dinámico, electroforesis Doppler con láser y microscopía electrónica de barrido (S-TEM). Se evaluó la actividad antibacteriana in vitro de las nanopartículas de ácido poliláctico con ofloxacina contra E. coli O157:H7 y nanopartículas de ácido poliláctico con vancomicina contra SARM, mediante el método de microdilución en caldo. Resultados: Se obtuvieron nanopartículas poliméricas con tamaños inferiores a 379 nm y carga superficial positiva de hasta 21 mV. Las nanopartículas cargadas con ofloxacina presentaron una concentración inhibitoria mínima (CIM50) de 0,001 μg/ml frente a E. coli O157:H7, valor 40 veces menor que la concentración de antibiótico libre necesaria para lograr el mismo efecto (CIM50=0,04 μg/ml). Para SARM, las nanopartículas mejoraron la potencia farmacológica in vitro de la vancomicina al exhibir una MIC50 de 0,005 μg/ml, comparada con la de 0,5 μg/ml del antibiótico libre. Conclusiones: Se mejoró el efecto antibacteriano de la ofloxacina y la vancomicina incorporadas en la matriz polimérica de ácido poliláctico. Las nanopartículas poliméricas constituirían una alternativa para el control de cepas bacterianas de interés en salud pública.

Abstract Introduction: Polymeric nanoparticles are promising nanotechnology tools to fight pathogenic bacteria resistant to conventional antibiotics. Objective: To synthesize polylactic acid nanoparticles loaded with ofloxacin and vancomycin, and to determine their antibacterial activity against Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA). Materials and methods: We synthesized ofloxacin or vancomycin loaded polylactic acid nanoparticles by the emulsification-solvent evaporation method, and characterized them by dynamic light scattering, laser Doppler electrophoresis and scanning electron microscopy. We evaluated in vitro antibacterial activity of ofloxacin- and vancomycin-loaded polylactic acid nanoparticles against E. coli O157:H7 and MRSA using the broth microdilution method. Results: Ofloxacin- and vancomycin-loaded polylactic acid nanoparticles registered a positive surface charge density of 21 mV and an average size lower than 379 nm. In vitro minimum inhibitory concentration (MIC50) of ofloxacin-polylactic acid nanoparticles was 0,001 μg/ml against E. coli O157:H7, i.e., 40 times lower than the free ofloxacin (MIC50: 0.04 μg/ml), indicating enhanced antibacterial activity while the in vitro MIC50 of vancomycin-polylactic acid nanoparticles was 0,005 μg/ml against MRSA, i.e., 100 times lower than that of free vancomycin (MIC50: 0.5 μg/ml). Conclusion: Polylactic acid nanoparticles loaded with ofloxacin and vancomycin showed a higher antibacterial activity. Polymeric nanoparticles are a possible alternative for drug design against pathogenic bacterial strains of public health interest.

Is drug-resistant Mycobacterium leprae a real cause for concern?: First approach to molecular monitoring of multibacillary Colombian patients with and without previous leprosy treatment / ¿Es la resistencia de Mycobacterium leprae a los medicamentos un verdadero motivo de preocupación?: Primera aproximación a la vigilancia molecular de pacientes colombianos multibacilares con tratamiento previo para lepra y sin él

Introduction: There is no information in Colombia on Mycobacterium leprae primary and secondary drug resistance in regards to the WHO-multidrug therapy regime. On the other hand, public health authorities around the world have issued various recommendations, one of which prompts for the immediate organization of resistance surveillance through simple molecular methods. Objective: To determine the prevalence of Mycobacterium leprae drug resistance to rifampicin, ofloxacin and dapsone in untreated and previously treated patients at the Centro Dermatológico Federico Lleras Acosta during the 1985-2004 period. Materials and methods: We conducted a retrospective study which included multibacillary patient biopsies through elective sampling: 381 of them from new patients and 560 from previously treated patients. Using a microtome, we obtained six slides from each skin biopsy preserved in paraffin, and we extracted M. leprae DNA. We amplified three molecular targets through PCR and obtained the patterns of drug resistance to dapsone, rifampicin and ofloxacin by reverse hybridization. Finally, we collected epidemiological, clinical and demographical data for analyses. Results: From 941 samples under study, 4.14% of them were resistant to one or more drugs, and 5.77 and 3.04% had resistant genotypes in new and previously treated patients, respectively. Total resistance for each drug was 0.43% for dapsone, 3.19% for rifampicin and 1.17% for ofloxacin. We found statistically significant differences for rifampicin and for the total population when comparing the results from untreated versus previously treated patients. Two thirds of the resistant samples were resistant to rifampicin alone or combined. Conclusions: The standard multidrug therapy schemes continue being effective for leprosy cases; however, it is necessary to guarantee adherence and regularity. Surveillance to drug resistance in new and previously treated leprosy cases should be established.

Introducción. Colombia no dispone de información sobre farmacorresistencia primaria y secundaria de Mycobacterium leprae al esquema de terapia múltiple de la Organización Mundial de la Salud (OMS) y las autoridades de salud pública del mundo han emitido varias recomendaciones, entre las cuales está organizar de inmediato la vigilancia a la resistencia empleando métodos moleculares simples. Objetivo. Determinar la prevalencia de la resistencia de M. leprae a rifampicina, ofloxacina y dapsona en pacientes del Centro Dermatológico Federico Lleras Acosta con tratamiento previo y sin él durante el período de 1985 a 2004. Materiales y métodos. Se realizó un estudio retrospectivo. Mediante muestreo electivo se incluyeron biopsias de pacientes multibacilares: 381 de pacientes nuevos y 560 de pacientes previamente tratados. Se obtuvieron con micrótomo seis cortes de cada biopsia de piel incluida en parafina, y se realizó la extracción de ADN de M. leprae. Se llevó a cabo la amplificación de tres blancos moleculares mediante PCR y se obtuvieron los patrones de resistencia a los medicamentos dapsona, rifampicina y ofloxacina por hibridación inversa. Se recolectaron datos epidemiológicos, clínicos y demográficos para llevar a cabo los análisis. Resultados. De las 941 muestras estudiadas, 4,14 % era resistente a uno o más fármacos, y se detectaron 5,77 y 3,04 % con genotipos resistentes en pacientes nuevos y previamente tratados, respectivamente. La resistencia total para cada fármaco fue de 0,43 % a dapsona, 3,19 % a rifampicina y 1,17 % a ofloxacina. Se encontró una diferencia estadísticamente significativa para rifampicina y para la población total al comparar los resultados de los pacientes no tratados con los de los pacientes tratados previamente. Dos tercios de las muestras resistentes lo fueron a rifampicina sola o combinada. Conclusiones. Los esquemas de terapia múltiple estándar siguen siendo efectivos para los casos de lepra; sin embargo, es necesario garantizar el cumplimiento y la regularidad y establecer la vigilancia de la farmacorresistencia en pacientes nuevos y previamente tratados.

A Comparative Study for Efficacy and Tolerability of Satranidazole Plus Ofloxacin Versus Ornidazole Plus Ofloxacin in Periodontal Infections.

Periodontal infections and related conditions like Chronic Gingivitis, Chronic Periodontitis, Pericoronitis, Peridontal & Periapical Abscess are common clinical problems, but sometimes Gingivitis and Periodontitis can be acute also. These all are generally treated by scaling and root planning, but studies have reported that despite conventional periodontal therapy certain sites continue to show periodontal tissue destruction. These periodontal infections can be controlled by antibiotics which are effective against Gram-negative aerobic and anaerobic bacteria and has good penetration in periodontal tissues. Objective: The purpose of the present study was to compare the efficacy and tolerability of a fixed dose combination of Satranidazole (300 mg) plus Ofloxacin (200 mg) versus fixed dose combination of Ornidazole (500 mg) plus Ofloxacin (200 mg) for the treatment of periodontal infections. Methods : One hundred and twelve adult patients (59 females and 53 males) with moderate to advanced periodontitis were enrolled and given fixed dose combination of Satranidazole (300 mg) plus Ofloxacin (200 mg) or Ornidazole (500 mg) plus Ofloxacin (200 mg) orally two times daily. Clinical assessment like Gingival Index, Periodontal Index, Mobility Index and VAS Score were done before and after the treatment. Clinical evaluation was performed on 3rd and 5th day after treatment. Results : At the baseline the values for Gingival Index, Periodontal Index, Mobility Index and VAS Score were comparable in both the groups. Both the treatment group have shown attenuation of Gingival Index, Periodontal Index, Mobility Index and VAS Score. However, treatment with Satranidazole plus Ofloxacin showed significantly (p< 0.05) better improvement in all clinical parameters compared to Ornidazole plus Ofloxacin treatment. Treatment with Satranidazole plus Ofloxacin was well tolerated and no serious adverse event was observed. 6 patients (15%) with Ornidazole plus Ofloxacin have shown side effects, which resulted in discontinuation of therapy. These side effects include allergy, nausea, vomiting & acidity. Conclusion : This study concludes that efficacy and tolerability of fixed dose combination of Satranidazole (300 mg) plus Ofloxacin (200 mg) is better than fixed dose combination of Ornidazole (500 mg) plus Ofloxacin (200 mg) in treatment of periodontal infections.

Antimicrobial Susceptibility of Stenotrophomonas maltophilia Isolates from Korea, and the Activity of Antimicrobial Combinations against the Isolates

The aim of this study was to determine antimicrobial susceptibility of recent clinical Stenotrophomonas maltophilia isolates from Korea, and to compare the activity levels of several combinations of antimicrobials. A total of 206 non-duplicate clinical isolates of S. maltophilia was collected in 2010 from 11 university hospitals. Antimicrobial susceptibility testing was performed using the Clinical Laboratory Standards Institute agar dilution method. In vitro activity of antimicrobial combinations was tested using the checkerboard method. The susceptibility rates to trimethoprim-sulfamethoxazole and minocycline were 96% and 99%, respectively. The susceptibility rate to levofloxacin was 64%. All of four antimicrobial combinations showed synergy against many S. maltophilia isolates. A combination of trimethoprim-sulfamethoxazole plus ticarcillin-clavulanate was most synergistic among the combinations. None of the combinations showed antagonistic activity. Therefore, some of the combinations may be more useful than individual drugs in the treatment of S. maltophilia infection. Further clinical studies are warranted to validate our in vitro test results.

Antimicrobial Susceptibility of Stenotrophomonas maltophilia Isolates from a Korean Tertiary Care Hospital

We determined the antimicrobial susceptibility of 90 clinical isolates of Stenotrophomonas maltophilia collected in 2009 at a tertiary care hospital in Korea. Trimethoprim-sulfamethoxazole, minocycline, and levofloxacin were active against most of the isolates tested. Moxifloxacin and tigecycline were also active and hold promise as therapeutic options for S. maltophilia infections.

Assessment of trends of ofloxacin resistance in Mycobacterium tuberculosis.

Purpose: Ofloxacin (OFX) is one of the potent fluoroquinolone (FQ) recommended to treat MDR-TB. Over a decade, the preexposure of this drug for the treatment of other bacterial infections has resulted in acquisition of FQ resistance among Mycobacterium tuberculosis strains. Considering this possibility, a study was undertaken in a tertiary care center in the capital city (India) to assess the drug resistance trends of OFX among susceptible and multidrug resistant (MDR) strains of M. tuberculosis. Materials and Methods: A total of 102 M. tuberculosis isolates (47 susceptible to first-line drugs and 55 MDR isolates) were screened for susceptibility testing of OFX with a critical concentration of 2 μg/ml by Lowenstein Jensen (LJ) proportion method. Results: The results showed 40 (85.1%) isolates among 47 susceptible isolates and 34 (61.8%) isolates among 55 MDR isolates, were found to be susceptible to OFX. Fisher's exact test showed significant P-value (0.0136) demonstrating 1.377 fold (95% confidence interval) increased risk to become resistant to OFX than susceptible isolates. These finding shows decreased OFX susceptibility is not only limited to MDR isolates but also increasingly seen in susceptible strains as a result of drug abuse. Conclusions: Our finding were not alarming, but highlights the general risk of acquiring resistance to OFX, jeopardizing the potential for these drugs to be used as second-line anti-TB agents in the management of drug-resistant TB and creating incurable TB strains.

Determinación de la susceptibilidad de cepas de Helicobacter pylori a Levofloxacino en formato pequeño y método de difusión en disco usando Agar yema de huevo / Antimicrobial susceptibility of helicobacter pylori to levofloxacin determined in a miniwell format and disk diffusion tests using egg yolk agar

OBJETIVOS: Determinar la concentración mínima inhibitoria (CMI) de Levofloxacino en cepas de HELICOBACTER PYLORI (HP). MATERIALES Y MÉTODOS: Se evaluaron 95 cepas peruanas de HP en métodos de agar dilución y difusión en disco, así como el coeficiente Pearson (r) y el efecto del inóculo. RESULTADOS: 36,9% (35 de 95) fueron resistentes a Levofloxacino (CMI>1μg/ml). CMI90 fue 16ug/ml (IC:90%). CMI de Levofloxacino no viró ante diferentes concentraciones del inóculo. r:-0,733 (p<0,001). CONCLUSIONES: La proporción de HP resistentes a Levofloxacino en Perú es mayor a la observada en países desarrollados. Se recomienda evaluar periódicamente la susceptibilidad antimicrobiana para elegir óptimas conductas terapéuticas.

OBJECTIVES: To determine the Minimum inhibitory concentration (MIC) of Levofloxacin against HELICOBACTER PYLORI (HP). MATERIALS AND METHODS: 95 HP Peruvian strains were evaluated in Agar dilution and Disk diffusion tests, as well as the Pearson Coefficient (r) and the inoculum’s effect. RESULTS: 36.9% (35 of 95) were resistant (MIC>1μg/ml) to Levofloxacin. MIC90 was 16ug/ ml (CI:90%). MIC of Levofloxacin did not change at different inoculum concentrations. r: -0.733 (p<0.001). CONCLUSIONS: The proportion of HP Levofloxacin resistant strains in Peru is higher than in developed countries. Periodic testing of antibiotic susceptibility is warranted to select the most accurate therapies.

Effect of efflux pump inhibitors on drug susceptibility of ofloxacin resistant Mycobacterium tuberculosis isolates.

Background & objectives In drug resistant, especially multi-drug resistant (MDR) tuberculosis, fluoroquinolones (FQs) are used as second line drugs. However, the incidence of FQ-resistant Mycobacterium tuberculosis is rapidly increasing which may be due to extensive use of FQs in the treatment of various other diseases. The most important known mechanism i.e., gyrA mutation in FQ resistance is not observed in a significant proportion of FQ resistant M. tuberculosis isolates suggesting that the resistance may be because of other mechanisms such as an active drug efflux pump. In this study we evaluated the role of the efflux pumps in quinolone resistance by using various inhibitors such as carbonyl cyanide m-chlorophenyl hydrazone (CCCP), 2,4-dinitrophenol (DNP) and verapamil, in clinical isolates of M. tuberculosis. Methods A total of 55 M. tuberculosis clinical isolates [45 ofloxacin (OFL) resistant and 10 ofloxacin sensitive] were tested by Resazurin microtitre assay (REMA) to observe the changes in ofloxacin minimum inhibitory concentration (MIC) levels in presence of efflux inhibitors as compared to control (without efflux inhibitor). Results The MIC levels of OFL showed 2-8 folds reduction in presence of CCCP (16/45; 35.5%), verapamil (24/45; 53.3%) and DNP (21/45; 46.6%) while in case of isolates identified as OFL sensitive these did not show any effect on ofloxacin MICs. In 11 of 45 (24.5%) isolates change in MIC levels was observed with all the three inhibitors. Overall 30 (66.6%) isolates had reduction in OFL MIC after treatment with these inhibitors. A total of eight isolates were sequenced for gyrA gene, of which, seven (87.5%) showed known mutations. Of the eight sequenced isolates, seven (87.5%) showed 2 to 8 fold change in MIC in presence of efflux inhibitors. Interpretation & conclusions Our findings suggest the involvement of active efflux pumps of both Major Facilitator Super Family (MFS) family (inhibited by CCCP and DNP) and ATP Binding Cassette (ABC) transporters (inhibited by verapamil) in the development of OFL resistance in M. tuberculosis isolates. Epidemiological significance of these findings needs to be determined in prospective studies with appropriate number of samples / isolates.

Reduced Levofloxacin Susceptibility in Clinical Respiratory Isolates of Haemophilus Influenzae Is Not yet Associated with Mutations in the DNA Gyrase and Topoisomerase II Genes in Korea

Among 155 clinical respiratory isolates of Haemophilus influenzae in Korea, 6 (3.9%) isolates had reduced levofloxacin susceptibility (MICs > or = 0.5 microg/mL). These six isolates had no significant quinolone resistance-determining region (QRDR) mutations in gyrA, gyrB, parC, or parE. This phenomenon suggests that neither evolution nor spread of any significant QRDRs mutations in clinical isolates occurred in Korea. Therefore, continued surveillance is necessary to observe the evolution of antibiotic-resistance and take measures to avoid the spread of drug-resistant clones.

Reduced Levofloxacin Susceptibility in Clinical Respiratory Isolates of Haemophilus Influenzae Is Not yet Associated with Mutations in the DNA Gyrase and Topoisomerase II Genes in Korea

Among 155 clinical respiratory isolates of Haemophilus influenzae in Korea, 6 (3.9%) isolates had reduced levofloxacin susceptibility (MICs > or = 0.5 microg/mL). These six isolates had no significant quinolone resistance-determining region (QRDR) mutations in gyrA, gyrB, parC, or parE. This phenomenon suggests that neither evolution nor spread of any significant QRDRs mutations in clinical isolates occurred in Korea. Therefore, continued surveillance is necessary to observe the evolution of antibiotic-resistance and take measures to avoid the spread of drug-resistant clones.

Regional Difference of Antibiotic Resistance of Helicobacter pylori Strains in Korea / 대한소화기학회지

BACKGROUND/AIMS: This study was performed to compare the prevalence rates of primary antibiotic resistance in Helicobacter pylori (H. pylori) isolates among different regions of Korea. METHODS: H. pylori were isolated from gastric mucosal biopsy specimens of 99 Koreans who lived in Gyeonggi (n=40), Kangwon province (n=40) and Busan (n=19) from April to August in 2008. All the patients had no history of H. pylori eradication therapy. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin, and moxifloxacin were tested according to the agar dilution method. RESULTS: There was a difference in resistance to clarithromycin in three institutes located among Gyeonggi (32.5%), Kangwon province (12.5%) and Busan (42.1%) by One way ANOVA test (p=0.027) and nonparametric Kruskal Wallis test (p=0.027). However, by post-hoc analysis, there was no statistically significant difference among three regions. Similarly, the other 7 antibiotics (amoxicillin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin and moxifloxacin) did not show any significant difference. CONCLUSIONS: There was no significant regional difference of the primary antibiotic resistance of H. pylori. However, the included patient number might not be enough for this conclusion demanding further evaluations.

Regional Difference of Antibiotic Resistance of Helicobacter pylori Strains in Korea / 대한소화기학회지

BACKGROUND/AIMS: This study was performed to compare the prevalence rates of primary antibiotic resistance in Helicobacter pylori (H. pylori) isolates among different regions of Korea. METHODS: H. pylori were isolated from gastric mucosal biopsy specimens of 99 Koreans who lived in Gyeonggi (n=40), Kangwon province (n=40) and Busan (n=19) from April to August in 2008. All the patients had no history of H. pylori eradication therapy. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin, and moxifloxacin were tested according to the agar dilution method. RESULTS: There was a difference in resistance to clarithromycin in three institutes located among Gyeonggi (32.5%), Kangwon province (12.5%) and Busan (42.1%) by One way ANOVA test (p=0.027) and nonparametric Kruskal Wallis test (p=0.027). However, by post-hoc analysis, there was no statistically significant difference among three regions. Similarly, the other 7 antibiotics (amoxicillin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin and moxifloxacin) did not show any significant difference. CONCLUSIONS: There was no significant regional difference of the primary antibiotic resistance of H. pylori. However, the included patient number might not be enough for this conclusion demanding further evaluations.

Antimicrobial susceptibility testing of newer quinolones against gram positive and gram negative clinical isolates

Antibiotic resistance development is an ongoing process associated with irrational antibiotic use. WHO recommends regular surveillance programs for monitoring of antibiotic resistance. The present study is a step in this direction. A total of 124 clinical isolates of Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa were collected from different hospitals in Karachi. In vitro antimicrobial susceptibility studies were carried out by agar dilution method using newer quinolones that included Gatifloxacin and Levofloxacin. It was observed that 50% [n=30] isolates of Staphylococcus aureus were resistant to gatifloxacin. Gatifloxacin was more active against Pseudomonas aeruginosa [n=23] and showing complete susceptibility with MIC 1mg/L except for three very resistant strains that shown resistance at even higher concentrations. Escherichia coli [n=45] has shown 15.5% and Klebsiella pneumoniae [n=26] 34.61% resistance to gatifloxacin. Levofloxacin was more active against Staphylococcus aureus and Escherichia coli showing complete susceptibility at 0.5 mg /L concentration. Pseudomonas aeruginosa and Klebsiella pneumoniae were found to be resistant to Levofloxacin showing 36.36% and 23.08% resistance respectively. The study strongly recommends the adherence to the antibiotic policy and regular susceptibility testing to overcome the problem associated with antimicrobial resistance

In vitro synergistic effect of doxycycline & ofloxacin in combination with ethanolic leaf extract of Vangueria spinosa against four pathogenic bacteria.

Background & objectives: The in vitro antibacterial activity of ethanolic leaf extract of Vangueria spinosa Roxb. (Rubiaceae) alone and in combination with antibiotics (doxycycline and ofloxacin) by means of fractional inhibitory concentration indices (FICI) as well as by the use of time-kill assays against one Gram-positive bacterium (Staphylococcus aureus) and three Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) was studied. Methods: Antibacterial activity was assayed by using the microdilution method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for the ethanolic leaf extract of V. spinosa alone and also in combination with antibiotics using the fractional inhibitory concentration (FIC) and time-kill assay method. Synergism was also tested using checker board dilution method. Results: MIC/MBC values for ethanolic leaf extract of V. spinosa against all the tested bacteria ranged between 25.5 - 52.6/22.4 - 60.5 μg/ml, for doxycycline 4.0/4.0 - 4.5 μg/ml and for ofloxacin 0.625 - 2.5/1. 25 - 5.0 μg/ml respectively. The average log reduction in viable cell count in time-kill assay ranged between 2.4 log10 - 4.5 log10 cfu/ml after 1 h of interaction and between 3.9 log10 -5.0 log10 cfu/ml after 3 h interaction in 1 × MIC to 4 × MIC. When leaf extract and antibiotics were combined, the average log reduction in viable cell count for doxycycline from 1.5 log10 - 5.18 log10 cfu/ml and for ofloxacin 3.06 log10- 5.39 log10 cfu/ml. Synergistic actions were observed in all the cases except against P. aeruginosa which showed an additive effect for ofloxacin and plant extract combination. Interpretation & conclusions: This study provides a preliminary report of synergistic activity of V. spinosa Roxb, ethanolic leaf extract with antibiotics.

Microbiota conjuntival e resistência a antibióticos em recém-nascidos prematuros internados em unidade de terapia intensiva / Conjunctival microbiota and antibiotics resistance in preterm newborns hospitalized in neonatal intensive care unit

OBJETIVO: Analisar a flora bacteriana da conjuntiva e o padrão de resistência a antibióticos em crianças recém-nascidas prematuras na Unidade de Terapia Intensiva Neonatal (UTIN) do Hospital das Clínicas da Universidade Federal de Pernambuco (UFPE). MÉTODOS: Foram analisadas amostras de secreção conjuntival de 48 recém-nascidos com permanência de pelo menos 48 horas na UTIN. RESULTADOS: Das 48 amostras 40 (83,3 por cento) apresentaram cultura positiva, com maior frequência de Staphyloccocus coagulase-negativo (43,2 por cento) e Staphyloccocus aureus (25,0 por cento). Foram consideradas multirresistentes 63,9 por cento das bactérias. Os antibióticos com maior sensibilidade no antibiograma foram gatifloxacino (97,2 por cento), vancomicina (94,4 por cento) e ofloxacino (94,4 por cento). CONCLUSÕES: A flora bacteriana da conjuntiva de prematuros na UTIN é diversificada, predominando as bactérias Gram-positivas, geralmente multirresistente a antibióticos.

PURPOSE: To analyze the conjunctival bacterial flora and the antibiotics resistance pattern in preterm newborns at the Neonatal Intensive Care Unit (NICU), in "Hospital das Clínicas da Universidade Federal de Pernambuco - UFPE". METHODS: Material from the conjunctival sac was obtained from 48 premature infants eyes that stayed at in NICU more than 48 hours. RESULTS: Culture analysis revealed that 40 (83.3 percent) were positive and the pathogens most commonly isolated included Coagulase-negative Staphylococcus (43.2 percent) and Staphylococcus aureus (25.0 percent), being 63.9 percent of the bacteria multiresistant. Antimicrobial test results demonstrated great sensitivity to gatifloxacin (97.2 percent), vancomycin (94.4 percent) and ofloxacin (94.4 percent). CONCLUSIONS: Conjunctival bacterial flora among newborns in NICU is varied, mainly Gram-positive, usually multiresistant to antibiotics.

Functionality of drug efflux pumps in antimonial resistant Leishmania donovani field isolates.

The recent upsurge of antimony (Sb) resistance is a major impediment to successful chemotherapy of visceral leishmaniasis (VL). Mechanisms involved in antimony resistance have demonstrated an upregulation of drug efflux pumps; however, the biological role drug efflux pumps in clinical isolates remains to be substantiated. Thus, in this study, the functionality of drug efflux pumps was measured in promastigotes and axenic amastigotes isolated from VL patients, who were either Sb-sensitive (AG83, 2001 and MC9) or resistant (NS2, 41 and GE1) using rhodamine123 as a substrate for multidrug resistant (MDR) pumps and calcein as a substrate for multidrug resistance-associated proteins (MRP) respectively; their specificity was confirmed using established blockers. Sb-resistant (Sb-R) isolates accumulated higher amounts of R123, as compared to Sb-sensitive (Sb-S) isolates. Verapamil, a MDR inhibitor failed to alter R123 accumulation, suggesting absence of classical MDR activity. In Sb-R isolates, both promastigotes and axenic amastigotes accumulated significantly lower amounts of calcein than Sb-S isolates and probenecid, an established pan MRP blocker, marginally increased calcein accumulation. Depletion of ATP dramatically increased calcein accumulation primarily in Sb-R isolates, indicating existence of a MRP-like pump, which was more active in Sb-R isolates. In conclusion, our data suggested that overfunctioning of a MRP-like pump contributed towards generation of Sb-R phenotype in L. donovani field isolates.

Effect of pharmacokinetic differences between men and women on pharmacodynamic target attainment of levofloxacin against streptococcus pneumoniae

A recently published study reported significantly slower systemic clearance, smaller steady-state volume of distribution, and greater Area Under the Curve [AUC] for levofloxacin in women compared to men [p<0.01]. Since the AUC[o-24]/MIC ratio predicts clinical and microbiological outcomes for fluoroquinolones, sex-related differences in levofloxacin pharmacokinetics may result in pharmacodynamic differences between men and women. To evaluate the pharmacodynamic [AUC[0-24]/MIC] of levofloxacin 500 mg and 750 mg against Streptococcus pneumoniae in men and women. Sex specific pharmacokinetic data were obtained from the previously mentioned study; likewise sex specific MIC data were obtained from the SENTRY Antimicrobial Surveillance Program [2004-2005], Monte Carlo simulations [10,000 subjects] were performed to calculate the probability of target attainment [PTA] as well as the cumulative fractions of response [CFR] for levofloxacin pharmacodynamic target of free AUC[0-24]/MIC >/= 33.7 for men and women. MIC[50] and MIC[90] for S. pneumoniae isolates were 1 and 1 microg/ml. 77.5% of all S. pneumoniae isolates have MIC value of 1 microg/ml. For the 500 mg levofloxacin dose, the PTA remained at acceptable range in women [85%] up to MIC 1 microg/ml, but declined very sharply in men [27%] at the same MIC; whereas the PTA approaching 100% in both men and women at MIC 1 microg/ml for the 750mg dose. At the mean time, while the CFR was 45.4% greater in women than men [41.7% for men, 87.1% for women] for 500 mg dose; it was only 2.3% greater in women [96.2% for men, 98.5% for women] for 750 mg dose. Sex-related differences in Levofloxacin pharmacokinetics result in substantially greater pharmacodynamic target attainment against S. pneumoniae in women than in men at the 500 mg dose, but not at the 750 mg dose. This finding suggests that levofloxacin 750 mg should be used to treat S. pneumoniae infections, especially in men

Comparative study of aminoglycosides [gentamicin and streptomycin] and fluoroquinolone [ofloxacin] antibiotics on testis tissue in rats: light and transmission electron microscopic study

To investigate the comparative effects of aminoglycosides and fluoroquinolones on testis structure and serum testosterone hormone level in rats. Forty male Wister rats were randomly divided into control [n=10] and experimental [n=30] groups. The experimental groups were subdivided into three groups of ten. Each received 5 mg/kg [IP] Gentamicin, 40mg/kg [IP] Streptomycin and 72mg/kg [IP] Ofloxacin daily for 14 days, respectively; however, the control group just received vehicle [IP]. In the fourteenth day, 5cc blood was collected for testosterone hormone then rats were killed and testis tissues were also prepared for light and electron microscopic study. Depletion of germ cells, germinal cells necrosis, especially in spermatogonia, and Leydig cells had an abnormal fibroblast-like appearance. Abnormal space between neighbour sertoli cells, mitochondria were lost cristae and vacuolated [none energized], lyzosome seen more in cytoplasm of sertoli cells and Veins congestion were seen in gentamicin and ofloxacin groups. These side effects were seen fewer in Streptomycin group. Gentamicin, Streptomycin and Ofloxacin have negative effects on testis architecture and germinal cells damages in rats. However, these side effects are seen less in the Streptomycin group. Therefore, it is recommended that usage of this drug have fewer side effects on male fertility

Activity of amikacin, ertapenem, ciprofloxacin and levofloxacin alone and in combination against resistant nosocomial pathogens by time-kill / Actividad letalidad-tiempo de la amicacina, la ertapenema, la ciprofloxacina y la levofloxacina, solas o en combinación, frente a los patógenos nosocomiales

OBJECTIVE: The purpose of this study was to determine the synergistic activity of amikacin/ertapenem, fluoroquinolones (ciprofloxacin and levofloxacin)/ertapenem and amikacin/fluoroquinolones combinations against resistant nosocomial pathogens. METHODS: Time-kill studies were performed over 24 hours using an inoculum of 5 x 106 - 1 x 107 cfu/mL. Antibiotics were tested at the 1 x MIC and 4 x MIC concentrations. RESULTS: At MIC and/or 4 x MIC concentrations, the antibiotic combinations showed additive or synergistic activity against Acinetobacter strains and extended spectrum beta-lactamase producing Klebsiella pneumoniae. In Escherichia coli strains, synergy was seen when amikacin was combined with ertapenem, ciprofloxacin and levofloxacin; ertapenem in combination with fluoroquinolones demonstrated antagonism. In Pseudomonas aeruginosa strains, synergistic effect was exhibited by ertapenem plus amikacin and ertapenem plus fluoroquinolones. The antibiotic combinations showed antagonistic interaction in methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. CONCLUSION: The antibiotic combinations showed additive or synergistic activity against many gram-negative pathogens.

OBJETIVO: El propósito del presente estudio fue determinar la actividad sinérgica de la amicacina/ ertapenema/fluoroquinolonas (ciprofloxacina y levofloxacina)/ertapenema y amicacina/y combinaciones de fluoroquinolonas frente a patógenos nosocomiales resistentes. MÉTODOS: Se realizaron estudios de letalidad-tiempo por 24 horas, usando un inóculo de 5 x 106 - 1 x 107 cfu/mL. Se probaron antibióticos en concentraciones de 1xCIM y 4xCIM. RESULTADOS: En concentraciones de CIM y/o 4 x CIM, las combinaciones de antibióticos mostraron actividad aditiva o sinergésica frente a las cepas Acinetobacter y Klebsiella pneumoniae productoras de la beta-lactamasa de espectro extendido. En las cepas de Escherichia coli, se observó sinergia cuando se combinó la amicacina con la ertapenema, la ciprofloxacina y la levofloxacina; la ertapenema en combinación con las fluoroquinolonas demostró antagonismo. En las cepas de Pseudomonas aeruginosa, se puso de manifiesto un efecto sinergésico al sumar la ertapenema con amicacina y la ertapenema con fluoroquinolonas. Las combinaciones antibióticas mostraron interacción antagonística en Staphylococcus aureus resistente a la meticilina y Enterococcus faecalis resistente a la vancomicina. CONCLUSIÓN: Las combinaciones antibióticas mostraron actividad aditiva o sinergésica frente a muchos patógenos gram-negativos.

Fluoroquinolone susceptibilities to methicillin-resistant and susceptible coagulase-negative Staphylococcus isolated from eye infection

PURPOSE: To evaluate the fluoroquinolone susceptibilities of ocular isolate coagulase-negative staphylococci (CoNS), identified at the Microbiology Laboratory - UNIFESP. DESIGN: Experimental laboratory investigation. METHODS: The minimum inhibitory concentrations (MICs) of 21 strains of methicillin-resistant coagulase-negative staphylococci (MRCoNS) and 22 methicillin-sensitive coagulase-negative staphylococci (MSCoNS) to ciprofloxacin, ofloxacin, gatifloxacin and moxifloxacin were determined, using the E-test method standardized by the Clinical and Laboratory Standards Institute (CLSI/NCCLS). RESULTS: The MIC90s (µg/ml) for the second generation of tested fluoroquinolones were higher than the fourth generation, especially for the methicillin-resistant coagulase-negative staphylococci group. CONCLUSION: Our results indicate that methicillin-sensitive coagulase-negative staphylococci are more susceptible to quinolones than are methicillin-resistant coagulase-negative staphylococci and that fourth generation fluoroquinolones appear to be more potent, affecting even coagulase-negative staphylococcal strains resistant to second generation fluoroquinolones.

OBJETIVOS: Avaliar a suscetibilidade a fluorquinolonas dos Staphylococcus coagulase-negativo (SCoN) identificados no Laboratório de Microbiologia Ocular da Unifesp. MÉTODOS: Foi determinada a concentração inibitória mínima de 21 cepas de SCoN meticilina-resistentes e 22 meticilina-sensíveis para ciprofloxacina, ofloxacina, gatifloxacina e moxifloxacina, utilizando o E-test estandartizado pelo CLSI/NCCLS. RESULTADOS: Os MIC90 (µg/ml) de 43 SCoN isolados para fluorquinolonas de segunda geração foram maiores do que os de quarta geração, principalmente para o grupo dos meticilina-resistentes. CONCLUSÃO: Nossos resultados indicam que Staphylococcus coagulase-negativo meticilina-sensíveis são mais suscetíveis às quinolonas do que os Staphylococcus coagulase-negativo meticilina-resistentes, fluorquinolonas de quarta geração parecem ser mais potentes, cobrindo inclusive cepas de Staphylococcus coagulase-negativo resistentes à segunda geração de fluorquinolonas.