Neratinib + fulvestrant + trastuzumab for HR-positive, HER2-negative, HER2-mutant metastatic breast cancer: outcomes and biomarker analysis from the SUMMIT trial.

BACKGROUND: HER2 mutations are targetable alterations in patients with hormone receptor-positive (HR+) metastatic breast cancer (MBC). In the SUMMIT basket study, patients with HER2-mutant MBC received neratinib monotherapy, neratinib + fulvestrant, or neratinib + fulvestrant + trastuzumab (N + F + T). We report results from 71 patients with HR+, HER2-mutant MBC, including 21 (seven in each arm) from a randomized substudy of fulvestrant versus fulvestrant + trastuzumab (F + T) versus N + F + T. PATIENTS AND METHODS: Patients with HR+ HER2-negative MBC with activating HER2 mutation(s) and prior cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) therapy received N + F + T (oral neratinib 240 mg/day with loperamide prophylaxis, intramuscular fulvestrant 500 mg on days 1, 15, and 29 of cycle 1 then q4w, intravenous trastuzumab 8 mg/kg then 6 mg/kg q3w) or F + T or fulvestrant alone. Those whose disease progressed on F + T or fulvestrant could cross-over to N + F + T. Efficacy endpoints included investigator-assessed objective response rate (ORR), clinical benefit rate (RECIST v1.1), duration of response, and progression-free survival (PFS). Plasma and/or formalin-fixed paraffin-embedded tissue samples were collected at baseline; plasma was collected during and at end of treatment. Extracted DNA was analyzed by next-generation sequencing. RESULTS: ORR for 57 N + F + T-treated patients was 39% [95% confidence interval (CI) 26% to 52%); median PFS was 8.3 months (95% CI 6.0-15.1 months). No responses occurred in fulvestrant- or F + T-treated patients; responses in patients crossing over to N + F + T supported the requirement for neratinib in the triplet. Responses were observed in patients with ductal and lobular histology, 1 or ≥1 HER2 mutations, and co-occurring HER3 mutations. Longitudinal circulating tumor DNA sequencing revealed acquisition of additional HER2 alterations, and mutations in genes including PIK3CA, enabling further precision targeting and possible re-response. CONCLUSIONS: The benefit of N + F + T for HR+ HER2-mutant MBC after progression on CDK4/6is is clinically meaningful and, based on this study, N + F + T has been included in the National Comprehensive Cancer Network treatment guidelines. SUMMIT has improved our understanding of the translational implications of targeting HER2 mutations with neratinib-based therapy.

Diagnostic performance of serological tests for swine brucellosis in the presence of false positive serological reactions.

Swine brucellosis caused by Brucella suis biovar 2 is an emerging disease in Europe. Currently used diagnostic tests for swine brucellosis detect antibodies to the O-polysaccharide (O-PS) of Brucella smooth lipopolysaccharide (S-LPS) but their specificity is compromised by false-positive serological reactions (FPSRs) when bacteria carrying cross-reacting O-PS infect pigs. FPSRs occur throughout Europe, and the only tool available for a specific B. suis diagnosis is the intradermal test with Brucella protein extracts free of O-PS or S-LPS. Using sera of 162 sows naturally infected by B. suis biovar 2, 406 brucellosis-free sows, and 218 pigs of brucellosis-free farms affected by FPSR, we assessed the diagnostic performance of an indirect ELISA with rough LPS (thus devoid of O-PS) and of gel immunodiffusion, counterimmunoelectrophoresis, latex agglutination and indirect ELISA with O-PS free proteins in comparison with several S-LPS tests (Rose Bengal, complement fixation, gel immunodiffusion and indirect ELISA). When adjusted to 100% specificity, the sensitivity of the rough LPS ELISA was very low (30%), and adoption of other cut-offs resulted in poor specificity/sensitivity ratios. Although their specificity was 100%, the sensitivity of protein tests (ELISA, latex agglutination, counterimmunoelectrophoresis, and gel immunodiffusion) was only moderate (45, 58, 61 and 63%, respectively). Among S-LPS tests, gel immunodiffusion was the only test showing acceptable sensitivity/specificity (68 and 100%, respectively). Despite these shortcomings, and when the purpose is to screen out FPSR at herd level, gel immunodiffusion tests may offer a technically simple and practical alternative to intradermal testing.

Studies on a suitable antibiotic therapy for treating swine brucellosis.

The aim of this work was developing effective treatments against Brucella suis biovar 2, responsible for swine brucellosis in Europe. MICs for antibiotics used classically in brucellosis and two new macrolides (tulathromycin and tildipirosin) were determined for 33 B. suis biovar 2 field and B. suis reference strains. MIC90 values ranged from 0.01 to 0.25 µg/mL. The best candidates, given alone or combined, were then evaluated in mice. Ten groups (n = 7) of BALB/c mice were inoculated (1 × 10(5) CFU/mouse) with a virulent B. suis biovar 2 field strain. All groups, excepting untreated control, were treated for 14 days with, respectively, doxycycline, dihydrostreptomycin, tulathromycin (one or two doses), or tildipirosin (one or two doses) given alone, and doxycycline combined with dihydrostreptomycin, tulathromycin, or tildipirosin. Combined tildipirosin treatment was the most effective, then selected for pig studies. Sixteen B. suis biovar 2 naturally infected sows were treated with oxytetracycline (20 mg/kg BW/daily) for 21 days. The half of these received also tildipirosin (4 mg/kg BW) in two doses with a 10-day interval. An extensive bacteriological study conducted ten days after ceasing treatments proved the efficacy of this combined oxytetracycline/tildipirosin treatment.

Performance of skin tests with allergens from B. melitensis B115 and rough B. abortus mutants for diagnosing swine brucellosis.

Swine brucellosis by Brucella suis biovar 2 is an emerging disease whose control is based on serological testing and culling. However, current serological tests detect antibodies to the O-polysaccharide (O/PS) moiety of Brucella smooth lipopolysaccharide (S-LPS), and thus lack specificity when infections by Yersinia enterocolitica O:9 and other gram-negative bacteria carrying cross-reacting O/PS occur. The skin test with the protein-rich brucellin extract obtained from rough B. melitensis B115 is assumed to be specific for discriminating these false positive serological reactions (FPSR). However, B115 strain, although unable to synthesize S-LPS, accumulates O/PS internally, which could cause diagnostic problems. Since the brucellin skin test has been seldom used in pigs and FPSR are common in these animals, we assessed its performance using cytosoluble protein extracts obtained from B. abortus rough mutants in manBcore or per genes (critical for O/PS biosynthesis) and B. melitensis B115. The diagnostic sensitivity and specificity were determined in B. suis biovar 2 culture positive and brucellosis free sows, and apparent prevalence in sows of unknown individual bacteriological and serological status belonging to B. suis biovar 2 naturally infected herds. Moreover, the specificity in discriminating brucellosis from FPSR was assessed in brucellosis free boars showing FPSR. The skin test with B. abortus ΔmanBcore and B. melitensis B115 allergens performed similarly, and the former one resulted in 100% specificity when testing animals showing FPSR in indirect ELISA, Rose Bengal and complement fixation serological tests. We conclude that O/PS-free genetically defined mutants represent an appropriate alternative to obtain Brucella protein extracts for diagnosing swine brucellosis.

Development of a selective culture medium for primary isolation of the main Brucella species.

Bacteriological diagnosis of brucellosis is performed by culturing animal samples directly on both Farrell medium (FM) and modified Thayer-Martin medium (mTM). However, despite inhibiting most contaminating microorganisms, FM also inhibits the growth of Brucella ovis and some B. melitensis and B. abortus strains. In contrast, mTM is adequate for growth of all Brucella species but only partially inhibitory for contaminants. Moreover, the performance of both culture media for isolating B. suis has never been established properly. We first determined the performance of both media for B. suis isolation, proving that FM significantly inhibits B. suis growth. We also determined the susceptibility of B. suis to the antibiotics contained in both selective media, proving that nalidixic acid and bacitracin are highly inhibitory, thus explaining the reduced performance of FM for B. suis isolation. Based on these results, a new selective medium (CITA) containing vancomycin, colistin, nystatin, nitrofurantoin, and amphotericin B was tested for isolation of the main Brucella species, including B. suis. CITA's performance was evaluated using reference contaminant strains but also field samples taken from brucella-infected animals or animals suspected of infection. CITA inhibited most contaminant microorganisms but allowed the growth of all Brucella species, to levels similar to those for both the control medium without antibiotics and mTM. Moreover, CITA medium was more sensitive than both mTM and FM for isolating all Brucella species from field samples. Altogether, these results demonstrate the adequate performance of CITA medium for the primary isolation of the main Brucella species, including B. suis.

Efficacy of bp26 and bp26/omp31 B. melitensis Rev.1 deletion mutants against Brucella ovis in rams.

Brucella melitensis Rev.1 is the most effective vaccine against B. ovis infection in sheep but induces antibodies interfering with B. melitensis diagnosis. Brucella BP26 and Omp31 proteins are differential diagnostic antigens. Single or double bp26 and omp31 Rev.1 deletion mutants have been proven effective against B. melitensis in sheep. Here, the CGV26 (deleted in bp26 gene) and CGV2631 (deleted in both bp26 and omp31 genes) mutants have been tested for efficacy against B. ovis in rams. Either inoculated subcutaneously or conjunctivally, both mutants conferred significant protection against B. ovis. The protection induced by CGV26 was similar to that of Rev.1 but significantly higher than that conferred by CGV2631. In conclusion, the CGV26 mutant, in association with the adequate diagnostic strategy, could be a useful alternative to Rev.1 for sheep vaccination against B. ovis infections in those countries performing simultaneously B. melitensis and B. ovis eradication campaigns.

Evaluation of a multiplex PCR assay (Bruce-ladder) for molecular typing of all Brucella species, including the vaccine strains.

An evaluation of a multiplex PCR assay (Bruce-ladder) was performed in seven laboratories using 625 Brucella strains from different animal and geographical origins. This robust test can differentiate in a single step all of the classical Brucella species, including those found in marine mammals and the S19, RB51, and Rev.1 vaccine strains.

Efficacy of several antibiotic combinations against Brucella melitensis Rev 1 experimental infection in BALB/c mice.

OBJECTIVES: The objective of the present study was to compare the efficacy of gentamicin given alone or combined with doxycycline with that of standard combination therapies in BALB/c mice experimentally infected with the Brucella melitensis vaccine strain Rev 1. METHODS: A standard broth microdilution method was applied to determine the susceptibility of strain Rev 1 to the clinically most relevant aminoglycosides. Eight groups of BALB/c mice were inoculated intraperitoneally (ip) with 1 x 10(6) cfu/mouse of strain Rev 1. While one group remained untreated, the other seven groups were treated 10 days later once a day for 14 days with (i) doxycycline given orally at 2 mg/day; (ii) streptomycin given ip at 0.4 mg/day; (iii) gentamicin given ip at 0.4 mg/day; (iv) rifampicin given orally at 0.5 mg/day; (v) doxycycline plus streptomycin; (vi) doxycycline plus gentamicin; and (vii) doxycycline plus rifampicin. The number of cfu per spleen and clearance of Rev 1 were assessed 34 days after inoculation. RESULTS: With the exception of streptomycin, strain Rev 1 was susceptible to all aminoglycosides tested. As expected, the combination doxycycline/streptomycin was ineffective against Rev 1 infection. In contrast, the combinations doxycycline/gentamicin and doxycycline/rifampicin were effective in the clearance of Rev 1 infection, but only the former improved significantly the therapeutic efficacy as compared with that of the antibiotics given alone. CONCLUSIONS: Gentamicin may be used along with doxycycline when the classical combination is considered the first choice in the treatment of patients with brucellosis due to B. melitensis vaccine strain Rev 1.

Abscesos periamigdalino y retrofaríngeo: estudio de 13 años / Peritonsillar and retropharyngeal abscesses: study of 13 years

Introducción Los abscesos periamigdalino y retrofaríngeo son las infecciones más frecuentes de tejidos profundos de cabeza y cuello. Se presenta una casuística sobre estas entidades. Material y métodos Estudio retrospectivo de los abscesos periamigdalino y retrofaríngeo en niños ingresados en la Unidad de Enfermedades Infecciosas de nuestro hospital entre enero de 1991 y enero de 2004. El diagnóstico se realizó fundamentalmente según criterios clínico-analíticos. Resultados Se estudian 54 casos, 10 con absceso retrofaríngeo y 44 con absceso periamigdalino, con edad media de 6,7 y 7,5 años, respectivamente. Se observa un discreto predominio en varones (1,45:1). Hay un aumento de casos diagnosticados desde 1997, con un máximo (9) en 2002. Un total de 29 niños habían recibido antibioterapia previa. Los principales síntomas y signos fueron: fiebre, odinofagia, adenopatías cervicales e hipertrofia amigdalar asimétrica. Todos los niños recibieron antibioterapia intravenosa. Se realizó punción-aspiración en 7 casos. Se practicó amigdalectomía en 11 niños, dos de ellos con absceso retrofaríngeo y nueve periamigdalino. De estos 11 pacientes, cinco tenían antecedentes de faringoamigdalitis de repetición y tres de absceso periamigdalino previo. Habían sido amigdalectomizados con anterioridad al desarrollo del absceso 3 niños. La mayoría de los casos presentaron una evolución favorable. Conclusiones En los últimos años se ha observado un aumento de la frecuencia de los abscesos periamigdalino y retrofaríngeo en la edad infantil. La mayor parte de los niños responden favorablemente al tratamiento conservador. La historia previa de amigdalitis de repetición constituye el principal factor de riesgo de recurrencia del absceso, y son estos pacientes los candidatos a amigdalectomía

Introduction Peritonsillar and retropharyngeal abscesses are the most common deep head and neck infections. We present a series of patients with these infections. Material and methods We performed a retrospective study of peritonsillar and retropharyngeal abscesses in children admitted to the Infectious Diseases Unit of our hospital between January 1991 and January 2004. Diagnosis was based mainly on clinical and laboratory findings. Results We studied 54 patients, 10 with retropharyngeal abscess and 44 with peritonsillar abscess. The mean age was 6.7 and 7.5 years respectively. There was a slight predominance of boys (1.45:1). The number of cases diagnosed increased from 1997, with a maximum (nine cases) in 2002. Twenty-nine children had received previous antibiotic therapy. The main symptoms and signs were: fever, odynophagia, cervical lymphadenitis, and asymmetric tonsillar hypertrophy. All children received intravenous antibiotic therapy. Puncture-aspiration was carried out in seven patients. Eleven children underwent tonsillectomy, two with retropharyngeal abscess and nine with peritonsillar abscess. Of these 11 patients, five had had several episodes of tonsillitis and three had previously had a peritonsillar abscess. Three children who developed an abscess had previously undergone tonsillectomy. In most patients, outcome was favorable. Conclusions In the last few years the frequency of peritonsillar and retropharyngeal abscesses has increased in the pediatric population. Most of the children have a good response to conservative treatment. The main risk factor for abscess recurrence is a previous history of repeated tonsillitis. Consequently, these patients are candidates for tonsillectomy

Ataxia cerebelosa aguda, eritema nodoso y orquiepididimitis tras gastroenteritis pro “Salmonella” D9 / Acute cerebellar ataxia, erythema nododum adn epidídimo-orchitis are complications of gastrointestinal infection by Salmonella D9

Se presenta el cado de un niño de siete años que sufre una gastroenteritis por Salmonella D9. A los quince dias de empezar la clínica, aparecen mialgias e inestabilidad en la marcha, dolor testicular y lesiones cutáneas. Fue diagnosticado de ataxia cerebelosa aguda, orquiepididimitis y eritema nodoso. Aunque todas estas complicaciones están descritas en la bibliogradía, resulta excepcional encontrarlas juntas en un mismo paciente

We present the case of a seve-year-old boy with gastroenteritis caused by Salmonella D9. Fifteen days after the clinical onset, he began to develop muscular pain, unsteady gait, testicular pain and skin lesions. The diagnoses were acute cerebellar ataxia, epididymo-orchitis and erythema nodosum. Each of these complications has been reported in the literature, but it is highly unusual to find all of them in the same patient

Documento de consenso sobre el tratamiento de la exposición a tuberculosis y de la infección tuberculosa latente en niños / Treatment of tuberculosis exposure and latent tuberculosis infection in children

Introducción La pobreza, la infección por el virus de la inmunodeficiencia humana (VIH), la resistencia a fármacos y la diseminación a partir de pacientes con infección latente son las causas más importantes de la pandemia actual de tuberculosis. En los países industrializados, la población inmigrante procedente de países en desarrollo y la falta de programas eficaces de control son las causas principales del incremento de la enfermedad. La situación de los niños es todavía más grave por ser más vulnerables a la enfermedad que los adultos. El mayor riesgo de contraer tuberculosis lo tienen los niños autóctonos que conviven con adultos que tienen factores de riesgo de tuberculosis y los niños inmigrantes y adoptados del tercer mundo. A pesar de que los niños desarrollan la enfermedad no son prácticamente nunca bacilíferos, el tratamiento adecuado de la exposición a tuberculosis bacilífera y de la infección tuberculosa latente en niños contribuye a crear una vigilancia estrecha de los núcleos familiares que asegura un riguroso estudio de contactos y contribuye a evitar formas graves de tuberculosis, más frecuentes en el niño. Objetivo El objetivo de este segundo documento de consenso del Grupo de Trabajo de Tuberculosis de la Sociedad de Infectología Pediátrica (SEIP) es unificar criterios para el tratamiento de las situaciones de exposición a tuberculosis e infección tuberculosa latente en niños y sensibilizar a las autoridades sanitarias acerca de la necesidad de acometer programas muy estrictos de detección de tuberculosis en población de riesgo

Introduction The most important causes of the current tuberculosis pandemic are poverty, HIV infection, drug resistance, and the spread of infection by patients with latent tuberculosis infection. In industrialized countries, the main reasons for the increase of this disease are immigration from developing countries and the lack of effective surveillance programs. The situation of children is even more serious as they are more vulnerable to the disease than adults. The children most at risk are those who live with adults at risk for tuberculosis, immigrant children, and adoptees from developing countries. Although children are bacilliferous only exceptionally, the appropriate management of bacilliferous tuberculosis exposure and latent tuberculosis infection in children contributes to the creation of close surveillance of nuclear families and rigorous study of contacts. Moreover, it could prevent serious forms of the disease, which are more frequent in children. Objective The principal objective of this second consensus document of the Spanish Society of Pediatric Infectious Diseases (Sociedad Española de Infectología Pediátrica [SEIP]) is to unify the criteria for the treatment of tuberculosis exposure and latent tuberculosis infection in children. A further aim is to increase awareness of the need for strict detection measures in high-risk populations among health authorities

Pericarditis tuberculosa diagnosticada por PCR en biopsia pericárdica / Tuberculous pericarditis diagnosed by PCR in pericardiac biopsy

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Fibrobroncoscopia en la tuberculosis endobronquial / Fiberoptic bronchoscopy in childhood endobronchial tuberculosis

La tuberculosis endobronquial (TBE) es una manifestación típica de la tuberculosis primaria infantil. La fibrobroncoscopia es una técnica que ayuda a su diagnóstico, pero ni su utilidad ni sus indicaciones están claramente definidas. Objetivos Analizar las fibrobroncoscopias llevadas a cabo a lo largo de 11 años (1992-2003) en niños con diagnóstico de tuberculosis, y realizar una revisión de la literatura especializada. Intentar establecer la utilidad actual de la fibrobroncoscopia en la tuberculosis infantil, y proponer unos criterios para determinar la indicación de esta técnica en estos niños. Métodos Se presenta una serie retrospectiva de 16 pacientes. Se indicó fibrobroncoscopia a los niños que presentaban en la radiografía de tórax: a) consolidación parenquimatosa persistente; b) adenopatía y consolidación; c) hiperinsuflación (enfisema); d) atelectasia, o e) estrechamiento de las vías respiratorias por adenopatías. Se revisaron las series publicadas sobre este tema, rescatándose 6 con valor para la comparación con la nuestra. Resultados Se encontró TBE en 7 niños (43 por ciento) y en tres (18 por ciento) compresión exclusivamente extrínseca. Los resultados de la microbiología a través de la fibrobroncoscopia no mejoraron a los métodos diagnósticos clásicos. La sensibilidad de los criterios radiológicos utilizados para sospechar TBE fue del 71 por ciento. Los hallazgos endoscópicos justificaron un cambio en el tratamiento en el 50 por ciento de los niños (adición de corticoides o cirugía), cifra similar a otras series. Conclusiones La fibrobroncoscopia no suele mejorar el diagnóstico microbiológico de la tuberculosis, pero es una herramienta útil en nuestro medio para decidir el tratamiento más adecuado de los niños con sospecha de TBE. En algunos casos, la tomografía computarizada (TC) puede hacerla innecesaria, pero en otros la fibrobroncoscopia puede ser, además, terapéutica (obstrucción por caseum, atelectasias). Es difícil establecer indicaciones de fibrobroncoscopia en casos de tuberculosis infantil, pero los criterios propuestos pueden ser una guía aceptable para determinar qué pacientes se beneficiarían más. No todos los niños con TBE necesitan corticoides (AU)

Tratamiento de corta duración de la leishmaniasis visceral con anfotericina B liposómica en pacientes inmunocompetentes / Short course treatment for visceral leishmaniasis with liposomal amphotericin B in immunocompetent patients

Introducción: La leishmaniasis visceral es una enfermedad endémica en el sur de Europa y los antimoniales pentavalentes han constituido su tratamiento clásico. Sin embargo, la aparición de fracasos terapéuticos, la larga duración del tratamiento y su toxicidad, han condicionado la introducción de nuevas terapias, como la anfotericina B liposómica (ABL). En este estudio se evalúa la eficacia y seguridad de ABL a una dosis máxima de 4 mg/kg/día los días 1 a 5 y 10. Pacientes y métodos: Estudio abierto, prospectivo y observacional realizado en 13 hospitales en España. El diagnóstico de leishmaniasis visceral se basó en la visualización de amastigotes de Leishmania sp. en el aspirado o promastigotes de Leishmania sp. en el cultivo de médula ósea o serología positiva, junto con la presencia de cuadro clínico compatible. Resultados: Se trataron 32 niños inmunocompetentes de edades comprendidas entre 7 meses y 7 años. Todos tuvieron una rápida respuesta clínica y el aspirado de médula ósea a los 21 días fue normal en el 100 por ciento de los 24 pacientes en quienes se realizó. En 8 niños la eficacia se evaluó por la respuesta clínica. Se detectaron dos recidivas, con lo que se logró la curación de 18 pacientes (90,0 por ciento) y del 87,5 por ciento de los pacientes con documentación microbiológica de la enfermedad. No se produjeron acontecimientos adversos. Conclusiones: Una dosis total de 24 mg/kg de ABL administrada en 6 dosis a lo largo de 10 días, es eficaz y segura en el tratamiento de la leishmaniasis visceral y permite además reducir la estancia hospitalaria (AU)

[Short course treatment for visceral leishmaniasis with liposomal amphotericin B in immunocompetent patients]. / Tratamiento de corta duración de la leishmaniasis visceral con anfotericina B liposómica en pacientes inmunocompetentes.

INTRODUCTION: Visceral leishmaniasis is endemic in southern Europe. Traditional treatment consists of pentavalent antimonial compounds. However, treatment failures, the treatment's long duration, and toxicity have led to the introduction of new therapies, such as liposomal amphotericin B (LAB). In this study we evaluate the safety and efficacy of LAB at a maximum dose of 4 mg/kg/day on days 1, 2, 3, 4, 5, and 10. PATIENTS AND METHODS: A prospective, observational, open study was conducted in 13 Spanish centers. The diagnosis of visceral leishmaniasis was based on visualization of Leishmanias sp. in bone marrow aspirate or culture or positive serology together with compatible clinical symptoms. RESULTS: Thirty-two immunocompetent children aged from 7 months to 7 years were treated. All the children had rapid clinical response and bone marrow aspirate performed on day 21 was normal in the 24 patients (100 %) who underwent this procedure. In the remaining eight children efficacy was assessed by clinical response. Two relapses were observed. Cure was achieved in 18 patients (90.0 %) and in 87.5 % of the patients with microbiological confirmation of the disease. No adverse events were detected. CONCLUSIONS: A total dosage of 24 mg/kg of liposomal amphotericin B administered in 6 doses within 10 days is safe and effective for the treatment of visceral leishmaniasis and reduces the length of hospital stay.

Achromobacter xylosoxidans bacteremia: a 10-year analysis of 54 cases.

Fifty-four cases of Achromobacter xylosoxidans bacteremia diagnosed over a 10-year period in patients from 2 months to 87 years of age were reviewed. Fifty-two episodes were nosocomial. The most frequent underlying condition was neoplasm (solid or hematological). The source of infection was a contaminated intravenous catheter in 35 patients (60%) and pneumonia in 6 patients. Eight (15%) patients died. The only risk factors significantly associated with mortality were age over 65 years and neutropenia. The results of in vitro susceptibility studies of the isolates showed that antibiotic therapy with antipseudomonal penicillins or carbapenems would be a reasonable choice. An epidemiological study conducted in the hemodialysis unit showed Achromobacter xylosoxidans in tap water and on the hands of two healthcare workers but not in the hemodialysis systems. Patients were probably contaminated when healthcare workers manipulated the intravenous catheters without wearing gloves.

Characterization of Brucella abortus O-polysaccharide and core lipopolysaccharide mutants and demonstration that a complete core is required for rough vaccines to be efficient against Brucella abortus and Brucella ovis in the mouse model.

Brucella abortus rough lipopolysaccharide (LPS) mutants were obtained by transposon insertion into two wbk genes (wbkA [putative glycosyltransferase; formerly rfbU] and per [perosamine synthetase]), into manB (pmm [phosphomannomutase; formerly rfbK]), and into an unassigned gene. Consistent with gene-predicted roles, electrophoretic analysis, 2-keto-3-manno-D-octulosonate measurements, and immunoblots with monoclonal antibodies to O-polysaccharide, outer and inner core epitopes showed no O-polysaccharide expression and no LPS core defects in the wbk mutants. The rough LPS of manB mutant lacked the outer core epitope and the gene was designated manB(core) to distinguish it from the wbk manB(O-Ag). The fourth gene (provisionally designated wa**) coded for a putative glycosyltransferase involved in inner core synthesis, but the mutant kept the outer core epitope. Differences in phage and polymyxin sensitivity, exposure or expression of outer membrane protein, core and lipid A epitopes, and lipid A acylation demonstrated that small changes in LPS core caused significant differences in B. abortus outer membrane topology. In mice, the mutants showed different degrees of attenuation and induced antibodies to rough LPS and outer membrane proteins. Core-defective mutants and strain RB51 were ineffective vaccines against B. abortus in mice. The mutants per and wbkA induced protection but less than the standard smooth vaccine S19, and controls suggested that anti O-polysaccharide antibodies accounted largely for the difference. Whereas no core-defective mutant was effective against B. ovis, S19, RB51, and the wbkA and per mutants afforded similar levels of protection. These results suggest that rough Brucella vaccines should carry a complete core for maximal effectiveness.