[Sialidase activity in women with bacterial vaginosis]. / Actividad sialidasa en mujeres con vaginosis bacteriana.

Bacterial vaginosis (VB) is a syndrome characterized by overgrowth of endogenous Gram negative bacterial flora and the lack of the normal flora. Within bacterial enzymes, sialidases have been considered a virulence factor of many pathogenic microorganisms colonizing the different mucous membranes. Their presence in vaginal discharges can be correlated with VB. The aim of this study was to detect the activity of this enzyme in women with this syndrome and without clinical evidence of genital infection. Out of a total 112 women studied, 51 were patients with VB and the other 61 women presented normal vaginal flora. For the quantification of enzyme activity, the technique based on the enzymatic hydrolysis of a derivative acid of the acetyl metoxifenil muramic acid was used. In the studied population both groups shared values from 0.5 to 5.1 nmoles of metoxifenol, whereas only 11 out of 52 patients with VB (21.17%), registered more than 5.1 nmoles. The presence of sialidase activity is not enough to confirm VB, except for values greater than 5.5 nmoles of the metoxifenol produced in the enzymatic reaction.

Molecular characterization of methicillin-resistant coagulase-negative staphylococci from a neonatal intensive care unit.

OBJECTIVE: To evaluate clonal dissemination of methicillin-resistant coagulase-negative staphylococci (CNS). SETTING: Neonatal intensive care unit of a 180-bed, university-affiliated general hospital. PATIENTS: Neonates admitted to the neonatal intensive care unit between March 1999 and October 2000, from whom CNS were isolated as a unique pathogen. Patients from other wards from whom epidemiologically unrelated staphylococci strains were obtained served as control-patients. METHODS: Conventional methods were used for phenotypic characterization of CNS. Methicillin resistance was determined by mecA polymerase chain reaction (PCR) amplification. Genotypic characterization was done by random amplification of DNA with degenerated primers (RAPD) and repetitive element sequence-based PCR (rep-PCR). RESULTS: Forty methicillin-resistant CNS isolates obtained from neonates were characterized as Staphylococcus epidermidis (33), S. hominis (5), S. warneri (1), and S. auricularis (1). Both RAPD and rep-PCR indicated the presence of 4 different clones among the 33 S. epidermidis isolates. In turn, the 4 randomly selected, epidemiologically unrelated methicillin-resistant CNS strains obtained from control-patients showed 3 new profiles by RAPD and 2 by rep-PCR, which differed from the corresponding patterns mentioned earlier. Persistence of S. hominis in a neonate could be assessed by both genotypic techniques. CONCLUSIONS: The molecular characterization of the methicillin-resistant CNS studied indicated dissemination of one particular methicillin-resistant CNS clone among the neonates in the ward studied. Although RAPD showed a superior power to discriminate among methicillin-resistant CNS isolates, both RAPD and rep-PCR detected intraspecific and interspecific genomic diversity.

Argentinean collaborative multicenter study on the in vitro comparative activity of piperacillin-tazobactam against selected bacterial isolates recovered from hospitalized patients.

The in vitro activity of piperacillin-tazobactam and several antibacterial drugs commonly used in Argentinean hospitals for the treatment of severe infections was determined against selected but consecutively isolated strains from clinical specimens recovered from hospitalized patients at 17 different hospitals from 9 Argentinean cities from different geographic areas during the period November 2001-March 2002. Out of 418 Enterobacteriaceae included in the Study 84% were susceptible to piperacillin-tazobactam. ESBLs putative producers were isolated at an extremely high rate since among those isolates obtained from patients with hospital acquired infections 56% of Klebsiella pneumoniae, 32% of Proteus mirabilis and 25% Escherichia coli were phenotypically considered as ESBLs producers Notably P.mirabilis is not considered by for screening for ESBL producers. ESBLs producers were 100% susceptible to imipenem and 70% were susceptible to piperacillin-tazobactam whereas more than 50% were resistant to levofloxacin. The isolates considered as amp C beta lactamase putative producers showed 99% susceptibility to carbapenems while 26.7% were resistant to piperacillin-tazobactam and 38.4% to levofloxacin. Noteworthy only 4% of the Enterobacteriaceae isolates were resistant to amikacin. Piperacillin-tazobactam was the most active agent against Pseudomonas aeruginosa isolates (MIC(90): 128 microg/ml; 78% susceptibility) but showed poor activity against Acinetobacter spp (MIC(90):>256 microg/ml; 21.7% susceptibility). Only 41.7% Acinetobacter spp isolates were susceptible to ampicillin-sulbactam. Piperacillin-tazobactam inhibited 100% of Haemophilus influenzae isolates (MIC(90) < 0.25 microg/ml) but only 16.6% of them were ampicillin resistant. The activity of piperacillin-tazobactam against oxacillin susceptible Staphylococcus aureus or coagulase negative staphylococci was excellent (MIC(90) 2 microg/ml; 100% susceptibility). Out of 150 enterococci 12 isolates (8%) were identified as E.faecium and only three isolates (2%), 2 E.faecium and 1 E.faecalis were vancomycin resistant. All the enterococci isolates were susceptible to linezolid. Piperacillin-tazobactam showed excellent activity (MIC(90) 2 microg/ml; 92% susceptibility). Regarding pneumococci all the isolates showed MICs of 16 microg/ml for piperacillin-tazobactam. Among 34 viridans group streptococci only 67% were penicillin susceptible and 85.2% ceftriaxone susceptible whereas piperacillin-tazobactam was very active (MIC(90) 4 microg/ml).Piperacillin-tazobactam is therefore a very interesting antibacterial drug to be used, preferably in combination (IE: amikacin-vancomycin) for the empiric treatment of severe infections occurring in hospitalized patients in Argentina. Caution must be taken for infections due to ESBL producers considering that the inoculum effect MICs can affect MIC values.

Infección extraintestinal debida a bacterias del género Campylobacter / Extraintestinal infections due to Campylobacter SPP

Campylobacter jejuni causa principalmente enteritis disenteriforme; los casos debidos a C. fetus son raros, mayormente bacteriemiaen inmunosuprimidos. Presentamos dos casos de enfermedad diarreica con bacteriemia, ambos con hemorragia digestiva,debida a C. jejuni, un caso inusual de infección de anerurisma de la arteria femoral y un caso de bacteriemia recurrente conprobable foco en marcapasos en un anciano sin otro factor de inmunosupresión, los dos últimos debidos a C. fetus. Todos lospacientes tuvieron evolución favorable. Recomendamos prestar atención a los hemocultivos que resulten positivos para efectuarlos subcultivos adecuados para recuperar, identificar y determinar la sensibilidad a los antimicrobianos de este tipo de bacterias microaerofílicas.

Campylobacter jejuni often causes enteritis; cases due to C. fetus are rare: it causes mostly bacteremia in patients with immunosuppression.We present two cases of diarrheal disease with bacteremia, both with gastrointestinal bleeding due to C. jejuni, an unusual case ofC. fetus infection of an aneurysm in the femoral artery, and one case of recurrent C. fetus bacteremia with probably focus in apacemaker in an elderly patient without another cause of immunosuppression. All patients had a favorable evolution. We recommendspecial attention to the positive blood cultures in order to recover and identify this type of microaerophilic bacteria, and determineantimicrobial susceptibility.

Synthesis and antibiotic activity of the tricyclic furo[3,2-c] isochromen-2-trione unit of the pyranonaphthoquinones.

The elaboration and biological activity of 15, containing the proposed pharmacophore for the antibiotic activity of the pyranonaphthoquinones, are reported. The synthetic strategy involved acid-catalyzed lactonization of mandelate 17 for isochroman ring formation, in combination with a Wittig-oxa-Michael functionalization of isochroman-3-ol derivative 20, a lactonization involving configurational inversion of a benzylic alcohol and a final AgO oxidation. Compound 15 showed activity against Staphylococcus aureus and Bacillus subtilis with MIC of 64 and 32 microg/mL, respectively.

Actividad sialidasa en mujeres con vaginosis bacteriana / Sialidase activity in women with bacterial vaginosis

La vaginosis bacteriana (VB) es un síndrome caracterizado por el sobrecrecimiento bacteriano deflora endógena Gram negativa, que desplaza a la flora lactobacilar normal. Dentro de las enzimasbacterianas, las sialidasas han sido consideradas factores de virulencia de muchos microorganismos patógenosque colonizan las distintas mucosas. Su presencia en fluidos vaginales puede estar correlacionada con VB. Elpropósito de este estudio fue comprobar la actividad de dicha enzima en mujeres con este síndrome y sin evidenciaclínica de infección genital. Se estudiaron 112 mujeres (51 fueron pacientes con VB y 61 mujeres conflora colonizante habitual). Para la cuantificación de la actividad sialidasa se empleó la técnica basada en lahidrólisis enzimática de un derivado ácido del ácido metoxifenil acetil murámico. En la población estudiada seencontró que ambos grupos mostraron valores comprendidos entre 0.5 a 5.1 nmoles de metoxifenol, mientrasque 11 de 52 pacientes con VB (21.17%), registraron valores superiores a 5.1 nmoles. La presencia de actividadsialidasa solamente no es índice de VB, excepto para valores mayores de 5.5 nmoles de metoxifenol, producidosen la reacción enzimática.

Bacterial vaginosis (VB) is a syndromecharacterized by overgrowth of endogenous Gram negative bacterial flora and the lack of the normalflora. Within bacterial enzymes, sialidases have been considered a virulence factor of many pathogenic microorganismscolonizing the different mucous membranes. Their presence in vaginal discharges can be correlatedwith VB. The aim of this study was to detect the activity of this enzyme in women with this syndrome andwithout clinical evidence of genital infection. Out of a total 112 women studied, 51 were patients with VB andthe other 61 women presented normal vaginal flora. For the quantification of enzyme activity, the technique basedon the enzymatic hydrolysis of a derivative acid of the acetyl metoxifenil muramic acid was used. In the studiedpopulation both groups shared values from 0.5 to 5.1 nmoles of metoxifenol, whereas only 11 out of 52 patientswith VB (21.17%), registered more than 5.1 nmoles. The presence of sialidase activity is not enough to confirmVB, except for values greater than 5.5 nmoles of the metoxifenol produced in the enzymatic reaction.

Species and serovars of enteropathogenic agents associated with acute diarrheal disease in Rosario, Argentina

Apresentamos as especies e serovars mais frequentes dos microorganismos enteropatogenos entre 1985 e 1990 em Rosario. Escherichia coli enteropatogenica (EPEC) foi a que predominou, afetando 144/570 (25,2 por cento) criancas; 0111 representou 41,8 por cento, 055 13,6 por cento, 0119 12,7 por cento. Entre as E. coli enterotoxigenicas (ETEC), ETEC-ST 0128:H21 e 155:H45 foram as mais frequentes. Entre os 570 pacientes, Shigella spp. foi diagnosticada em 50 (8,8 por cento); S. sonnei 1,6 por cento e S. dysenteriae tipo 2 (1 por cento). Foram encontrados Campylobacter spp em 6,1 por cento dos pacientes; C. jejuni 4,6 por cento, C. coli 1,4 por cento e C. lari 0,2 por cento; exceto os grupos 0 13/50 e 0 4 (dois de cada um), nao foram encontrados serogrupos predominantes...

Caracterización de Streptococcus causantes de mastitis bovina en Argentina, mediante métodos fenotípicos y genotípicos / Characterisation of streptococcus causing bovine mastitis in Argentina using genotypic and phenotypic methods

En este trabajo se han caracterizado aislamientos de Streptococcus de leche de vacas con mastitis de la cuenca lechera de Santa Fe y Córdoba, Argentina. Se recuperaron 30 aislamientos de 169 muestras de leche, que fueron identificados bioquímica y serológicamente como Streptococcus agalactiae (22 aislamientos), S. dysgalactiae (seis aislamientos) y S. uberis (dos aislamientos). El análisis genotípico por RAPD mostró cuatro cepas distintas en la población de S. agalactiae, seis en la de S. dysgalactiae y dos en S. uberis. Cada uno de los cuatro rodeos analizados se mostró colonizado por una única cepa de S. agalactiae, mientras que cepas diferentes de S. dysgalactiae coexistieron en un rodeo. Se identificó un fragmento de ADN común a todos los aislamientos de S. agalactiae estudiados, ausente en las otras especies. Estos resultados indican que las metodologías empleadas constituyen una herramienta eficaz para el diagnóstico y la investigación epidemiológica de estreptococos en ganado bovino.

Faringitis causada por streptococcus beta hemolítico grupo G: comunicacion breve / Pharyngitis caused for Streptococcus beta hemoglytic group G: brief report

En el presente trabajo se describe la aparición de un Streptococcus beta hemolítico no común, productor de faringitis. Se estudiaron miembros de una familia, de los cuales 2 presentaban sintomatología aguda. Estudiados los exudados faríngeos procesados de acuerdo con la metodología convencional y tipificados serológicamente el Streptococcus beta hemolítico desarrollado se determinó como perteneciente al Grupo G. Por las secuelas no supurativas (fiebre reumática y glomérulo nefritis) que el mismo puede causar, es que todos los laboratorios de Microbiología deben disponer de esquemas completos de identificación de estreptococos, no considerando al Streptococcus pyogenes como único patógeno faríngeo

Esquema simplificado de identificacion de las especies de staphylococcus coagulasa-negativa aislados de infecciones humanas / Identificacion simplified scheme for coagulase-negative staphylococcus strains isolated from human infections

Neste trabalho se identificaram 100 cepas de estafilococos coagulasa negativa de diferentes mostras clínicas. Buscando a correlaçäo entre homologia de DNA e características fenotípicas foi dividido em 2 grandes grupos pela sensibilidade à novobiocina e agregando a detecçäo de beta-galactosidasa e oxidasa em que se determinou 4 grupos (quadro 1): grupo de espécies de S. epidermidis, grupo de espécies de S.simulans: grupo de espécies de S. sapiophyticus e grupo de espécie de S. sciuri que säo factíveis de resolver em todo laboratório de microbiologia clínica. Por agregado de outras provas simples: detecçäo de ureasa, fosfatasa alcalina e beta-glucosidasa e detecçäo de aeróbica de acidez de maltosa, trehalosa e manitol se determinam as espécies de grupo S. epidermidis (quadro 2). Geralmente dada a maior frequência do S. epidermidis suficiente somente a detecäo de ureasa e fosfatasa. As espécies do grupo S. simulans se identificam com a determinaçäo de ureasa: fosfatasa alcalina e acidez de manitol (quadro 3): com a realizaçäo de ureasa e acidificaçäo de sacarosa e arabinosa se estabelece as espécies do grupo S. saprophyticus e unicamente por meio da rafinosa as espécies do grupo S. sciuri (quadro 5). A correlaçäo destas mínimas provas obtidas em nossas determinaçöes com as numerosissimas realizadas segundo apresenta o Manual de Bergey 9a. ediçäo, nos permite considerar a aplicabilidade deste esquema simples e rápido para diferenciar as espécies coagulasa negativa do gênero Staphyloccocus na maioria dos laboratórios de bacteriologia clínica

Phenotypic and getotypic study of Streptococcus agalactiae in vagina of pregnant women in Argentina

Streptococcus agalactiae (GBS) is a leading cause of serious neonatal infection. In this study we determine the prevalence, serotype distribution and genomic diversity of GBS in vagina of pregnant women.Vaginal swabs of 531 pregnant women were cultured on Columbia Agar Base Blood, GBS Agar Base and Todd Hewitt Broth. GBS were characterized by group and type-specific agglutination. Genomic polymorphism was studied by random amplification of DNA (RAPD). Seventeen patients (3.2 percent) were positive for GBS, resulting serotype III the most frequent. RAPD detected 16 different RAPD profiles from 21 GBS studied, revealing a good discriminatory power. In this sense, this method showed different genotype from GBS serotype III recovered from successive samples of two patients, suggesting reinfection. In conclusion, the combination of RAPD and serotyping appear promising for epidemiological studies. Finally, findings of reinfection after therapy during pregnancy, led us to suggest performing prenatal GBS screening and intrapartum prophylaxis in order to reduce neonatal risk.

Prevención de la transmisión materno-neonatal de Sptreptococcus agalactiae resistente al tratamiento: analisis de un caso / Prevention of the maternal-neonatal transmission of streptococcus agalactiae resistent to the treatment. Analysis of a case

Se presenta el caso de una paciente gestante con antecedente de un embarazo previo, que concluyó en sepsis neonatal de evolución falta. La colonización por Streptococcus agalactiae (serotipo III) tanto en heces como en sangre del neonato fallecido, en los loquios materno, así como en sucesivos aislamientos provenientes de exudades vaginales posteriores al parto, fue verificada mediante metolodolgía fenotípica (biotipificación y serotipificación)

Characterization of clinical isolates of Streptococcus agalactiae by random amplified polymorphic DNA using degenerate oligonucleotides

Epidemioiogicai studies of Streptococcus agalactiae strains have been limited by the lack of sensitive and discriminatory methods for comparing clinical isolates. Serotyping, albeit a widely used methodology, has been shown to possess low capability to distinguish between epidemiologically related and unrelated isolates. We have employed here a random amplification of polymorphic DNA (RAPD) assay, using degenerate oligonucleotides as primers, to characterize S. agalactiae isolates from related or unrelated clinical samples. Epidemioiogically-related isolates (mother-infant pairs) showed identical profiles by this methodology. On the contrary, 12 epidemioiogically-unrelated isolates (ciassified into 5 different serotypes) resulted in ll distinct RAPD patterns. This suggests that the proposed modified RAPD assay provides a highly discriminatory tool for the analysis of genomic diversity among isolates from pathogenic organisms.