Evaluation of the in-vitro cidal activity and toxicity of a novel peroxygen biocide: 2-butanone peroxide.

The monomer of 2-butanone peroxide is a novel peroxygen derivative with potential use as biocide in the hospital environment. The aim of this study was to test the biocidal activity of different concentrations of the compound against American Tissue Culture Collection strains from 11 different micro-organisms, including bacteria, mycobacteria, spores, fungi and virus, following the European Standard guidelines. Toxicity tests were also carried out following United States Environmental Protection Agency Standards. 2-Butanone peroxide exhibited biocidal activity at 0.12% against Legionella pneumophila, at 0.5% against Escherichia coli, Pseudomonas aeruginosa and Enterococcus hirae, and at 1% against Staphylococcus aureus after 5 min contact at room temperature. Mycobactericidal activity was obtained at 0.5% after 60 min contact at 20 degrees C, and sporicidal activity was obtained at 4% after 60 min at 40 degrees C. Good fungicidal (against yeasts and moulds) and virucidal (adenovirus and poliovirus) activities were obtained at 0.5% after 60 min contact. Toxicity assessment showed negative results in the acute dermal irritation test, acute eye irritation test and acute oral toxicity test. The skin sensitisation test was negative. The safety profile in the toxicity tests and the basic cidal activity against the strains tested suggest that 2-butanone peroxide in the control of hospital infections.

[Improvement of bactericide activity in hospital treatment of gram positive infections]. / Optimización de la actividad bactericida en el tratamiento hospitalario de infecciones por grampositivos.

Vancomycin is currently the standard treatment of gram-positive bacteria inducted nosocomial infections. However its bactericidal activity may be affected by different factors related to its antibacterial activity, pharmacokinetic properties or the infecting bacteria. Based on these facts, this article reviews the clinical importance that bactericidal activity has against susceptible bacteria and the compromise of this activity due to inadequate pharmacodynamic parameter values. From the bacterial target perspective, the clinical importance of the compromised bactericidal activity due to the decreased susceptibility, tolerance, heteroresistance and resistance is reviewed. In addition the characteristics of an antimicrobial targeted for gram positive nosocomial infections as well as the degree of adhesion to them of the bactericidal antibiotic daptomycin are described.

[Why not revisiting tinidazole as potential treatment of odontogenic infections?]. / Por qué no reevaluar el tinidazol como tratamiento potencial de infecciones odontogénicas?

Tinidazole is a 5-nitroimidazole initially introduced into clinical medicine in 1969 for the treatment of unicellular parasites. Tinidazole offers selective bactericidal activity, not influenced by the inoculum size, against anaerobic bacteria, that make it of theoretical interest against periodontopathogen infections. This article reviews the required characteristics of an antibiotic directed to odontogenic anaerobic infections, as well as the pharmacodynamic pitfalls of common antibiotic treatments. In addition the in vitro, pharmacokinetic and pharmacodynamic properties of tinidazole are reviewed, assessing the degree of its adhesion to the required characteristics, as well as identifying the gaps to be fulfilled prior to its use in this medical field. Tinidazole offers interesting characteristics making worthy investigations as a candidate for the treatment of anaerobic odontogenic infections. \

beta-lactam susceptibility of Escherichia coli isolates from urinary tract infections exhibiting different resistance phenotypes.

Susceptibility to beta-lactams was determined in 203 recent Spanish E. coli isolates from urinary tract infections exhibiting different resistance phenotypes: a) susceptible (n = 60); b) quinolone-resistant (n = 45); c) penicillinase (n=64); d) hyperproduction of penicillinase (n=8); e) inhibitor resistant TEM (IRT) (n=18), and f) extended spectrum betalactamase (ESBL) (n=8).Minimum inhibitory concentration (MIC) determination by agar dilution and susceptibility tests for ESBL detection by macrodilution were performed following CLSI recommendations. All the beta-lactams tested showed high activity against susceptible and penicillinase phenotypes, with close to 100 % susceptibility. Hyperproduction of penicillinase increased MIC90 values for all antibiotics except for meropenem, with 100% resistance to cefuroxime and amoxicillin/clavulanic acid, and 100% susceptibility to cefotaxime, piperacillin/tazobactam and meropenem. All the antibiotics, except for amoxicillin/clavulanic acid, exhibited high activity against IRT. Meropenem, cefminox and piperacillin/tazobactam exhibited the highest activity against ESBL, followed by amoxicillin/clavulanic acid. The most active compound among the parenteral antibiotics was meropenem, regardless of the resistance phenotype. Among the oral antibiotics, the most active compound was cefditoren with the exception of ESBL where amoxicillin/clavulanic acid where the MIC90 value was one dilution lower.

Isolation of Legionella species/serogroups from water cooling systems compared with potable water systems in Spanish healthcare facilities.

Surveillance of Legionella spp. in hospital water systems was performed in forty-four inpatient healthcare facilities in Spain during 2005-2006. A total of 2,341 samples were collected: 470 from cooling systems (cooling towers) and 1,871 from potable water systems. The latter included 211 from cold-water tanks and 260 from hot-water tanks, totalling 471 from central water reservoirs 136 from showers, 1,172 from unfiltered taps and 92 from filtered taps, totalling 1,400 from peripheral points. Temperature, chlorine levels and the presence of Legionella spp. were determined. In all, 373 (15.9%) samples yielded Legionella spp. Significantly higher isolation rates were obtained from cooling towers (23.8%) versus cold- and hot-water tanks (approximately 4.7%), due to the significantly higher number of samples positive for serogroup 1 (19.4 vs 0.9-3.5%). In potable water systems, no differences were found between central water tanks and showers, but significant differences in isolation rates between central water tanks and unfiltered taps were observed (4.7 vs 19.6%) due to differences in non-serogroup 1 L. pneumophila. Filters significantly decreased isolation rates of these serotypes (11 vs 0%). Some seasonal differences were noted, with higher isolation rates in summer for legionella serogroup 1 in cooling systems and for L. pneumophila serogroups 2-14 in potable water systems. In regression models, higher temperatures were associated with colonisation in cooling systems, while lower chlorine levels were associated with colonisation in potable water systems.

Very high resistance to amoxicillin in Streptococcus pneumoniae: an epidemiological fact or a technical issue?

To explore reproducibility of high amoxicillin minimum inhibitory concentrations (MIC(AMX) ), isolates received during 2002 and 2003 in the National Reference Laboratory of Streptococcus pneumoniae with an amoxicillin MIC of 16 microg/ml (43 strains) and 8 g/ml (12 strains) when singly determined on a routine basis in this center by agar dilution, were retested 10 times by agar dilution and microdilution following NCCLS guidelines, not only using double dilutions but also dilution steps of 2 microg/ml (i.e, 2, 4, 6, 8, 10, 12, 14 and 16 microg/ml). A significant (p<0.05) shift to a higher MIC(AMX )was obtained with microdilution vs. agar dilution. Routine MIC(AMX )of 16 microg/ml were confirmed in 0 strains by agar dilution and in 6 by microdilution, when retested. These 6 strains presented a modal MIC(AMX )value of 10 microg/ml (5 cases) and of 14 micro g/ml (1 case) when using 2 microg/ml microdilution steps. There is low reproducibility of the highest MIC(AMX )values.

Utilidad del 99mtc-sestamibi para diagnóstico del carcinoma oculto de mama. a propósito de un caso / Usefulness of 99mTc-sestamibi scintimammography for the diagnosis of occult breast carcinoma. A case report

Se describe el caso de una paciente con carcinoma oculto de mama con exploración clínica de ambas mamas normal, presentando adenopatías axilares izquierdas sospechosas de infiltración neoplásica. En el estudio radiológico y ecográfico mamarios se apreciaron nódulos bien delimitados de naturaleza quística en cuadrante superior interno de mama izquierda, sin que se evidenciaran signos de presencia tumoral. El estudio isotópico con 99mTc-sestamibi mostró captación leve difusa en los cuadrantes superiores de la mama, así como intensa captación isotópica en la axila homolateral. Se realizó la biopsia de la mama en los puntos de hipercaptación, según la imagen gammagráfica, sin que macroscópicamente se objetivaran lesiones sospechosas. El estudio histopatológico fue de extensión intraductal y linfática por carcinoma ductal infiltrante en todas las muestras. (AU)