Primer reporte de Escherichia coli diarreogénica en población pediátrica ambulatoria con diarrea atendida en la ciudad de La Plata, Argentina / First report of diarrheagenic Escherichia coli in pediatric outpatient population with diarrhea in La Plata, Argentina

Resumen Escherichia coli diarreogénica comprende un grupo heterogéneo de cepas que presentan diversos factores de virulencia y causan diferentes síndromes diarreicos. Los patotipos más estudiados son Escherichia coli enteropatogénica (EPEC), Escherichia coli enterotoxigé-nica (ETEC), Escherichia coli enteroagregativa (EAEC), Escherichia coli enteroinvasiva (EIEC) y Escherichia coli productora de toxina Shiga (STEC). El objetivo de este estudio fue estimar la frecuencia de infección de los diversos patotipos de E. coli diarreogénica en una población pediátrica ambulatoria con diarrea, atendida en el Hospital Sor María Ludovica de La Plata, Argentina, durante el período mayo-octubre de 2017. Los patotipos fueron detectados mediante la amplificación molecular de ocho genes de virulencia característicos. Se estudiaron las heces de 211 ninos (76% menores de 5 años). Se detectó infección con E. coli diarreogénica en el 12,3% (n = 26/211) de los niños con diarrea. Los patotipos identificados fueron EAEC, ETEC (todos lt positivos), EPEC y STEC (stx2 y eae positivos). El patotipo EAEC fue prevalente en todos los grupos etarios, mientras que los patotipos ETEC, EPEC y STEC solamente se observaron en niñnos menores de 5 anños. Este estudio constituye el primer reporte de detección por técnicas de amplificación molecular de Escherichia coli diarreogénica en una población pediátrica ambulatoria con diarrea, de la zona de La Plata. Se necesitan estudios más amplios que incluyan la caracterización de los aislamientos abarcando un mayor número de genes, controles asintomáticos, distintas épocas del ano y población de diversas áreas geográficas para esclarecer la relevancia de la infección por E. coli diarreogénica en niños de Argentina.

Abstract Diarrheagenic Escherichia coli is a heterogeneous group of strains that presents various virulence factors and causes different diarrheal syndromes. The most studied pat-hotypes are enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enteroaggregative Escherichia coli (EAEC), enteroinvasive Escherichia coli (EIEC) and Shiga toxin-producing Escherichia coli (STEC). The objective was to estimate the frequency of infec-tion of diarrheagenic E. coli pathotypes in children with diarrhea, attended at the Sor María Ludovica Hospital in La Plata, Argentina, during the period May-October 2017. E. coli pathotypes were detected by molecular amplification of eight characteristic virulence genes. The feces of 211 children (76% under 5 years) were studied. Infection with diarrheagenic E. coli was detected in 12.3% of the samples. The pathotypes were EAEC (10.43%), ETEC (1.42%, all of them positive for thermolabile toxin), EPEC (0.95%) and STEC (0.47%, positive for Shiga toxin 2). The EAEC pathotype was prevalent in children of all age groups, while ETEC, EPEC and STEC were only observed in children under 5 years of age. This study constitutes the first report of diarrheagenic Escherichia coli detection in an outpatient pediatric population with diarrhea from La Plata, using molecular amplification techniques. Broader future studies, including the charac-terization of the isolates with the largest number of genes, asymptomatic controls, different times of the year and population from different geographic areas will be necessary to clarify the relevance of diarrheagenic E. coli infection in children from Argentina.

Características clínicas y microbiológicas de infecciones de piel y partes blandas en pacientes pediátricos de dos hospitales de Buenos Aires / Skin and soft tissue infections in pediatrics

Las infecciones de piel y partes blandas (IPPB) en niños son una de las principales causas de prescripción de antimicrobianos. El objetivo del estudio fue describir las características clínicas y microbiológicas de las IPPB ambulatorias de niños asistidos en dos hospitales zonales. Se realizó un estudio prospectivo entre el 1/11/2017 y el 1/11/2018. Se incluyeron pacientes entre 1 mes y 15 años internados en dos hospitales. Se evaluó: edad, sexo, localidad, factores predisponentes, tipo de IPPB, muestras biológicas realizadas, aislamiento microbiológico, tratamiento empírico indicado y evolución del cuadro. Se realizó antibiograma y determinación genética. Se calculó chi2, IC95, OR; α=5%. N= 94. 58,7% masculinos. 12 pacientes <1 año, 85 >1 año (promedio de edad 4 años, 1-15). El 36% de Tandil y 63,8% de Florencio Varela. El 59,6% corresponden a IPPB purulentas. Se aislaron microorganismos en un 59,6%. Los aislamientos principales: SAMR (40,4%), SAMS (7,4%), S. agalactiae (2,1%) y S. pyogenes (2,1%). El 100% de SAMR son portadores de gen mecA y SCCmec tipo IV, sin multirresistencia. No hubo diferencia estadística entre los factores de riesgo evaluados para el desarrollo de IPPB por SAMR. El 52,1% de los niños recibió tratamiento antibiótico combinado, siendo la más indicada TMS-SMX + CLI en 36 eventos. (38,3%). La evolución fue favorable: no hubo diferencia significativa entre el subgrupo que se aisló SAMR y el que no se aisló SAMR; 91,9% (34/37) y 92,6% (50/54) correspondientemente (chi2: 0,01; p= 0,97 IC95: 0,26-3,88). El principal agente etiológico fue SAMRco, debiendo adecuar los tratamientos a este microorganismo.

Skin and soft tissue infections (SSIs) in children are one of the main causes of antimicrobial prescription. The aim of the study was to describe the clinical and microbiological characteristics of outpatient SSIs in children attended in two hospitals. A prospective study was conducted between 11/1/2017 and 11/1/2018. Patients between 1 month and 15 years old, hospitalized were included. We evaluated: age, sex, locality, predisposing factors, type of IPPB, biological samples taken, microbiological isolation, empirical treatment indicated and evolution of the condition. An antibiogram and genetic determination were performed. Chi2, CI95, OR; α=5% were calculated. N= 94. 58.7% male. 12 patients <1 year, 85 >1 year (mean age 4 years, 1-15). 36% were from Tandil and 63.8% from Florencio Varela. 59.6% corresponded to purulent SSIs. The diagnostic yield was 59.6%. Main isolates: MRSA (40.4%), MSSA (7.4%), S. agalactiae (2.1%) and S. pyogenes (2.1%). 100% of MRSA carried the mecA gene and SCCmec type IV, with no multidrug resistance. There was no statistical difference between the risk factors evaluated. 52.1% of children received combined antibiotic treatment, the most indicated being TMS-SMX + CLI in 36 events. (38,3%). Evolution was favorable: there was no significant difference between the subgroup that isolated MRSA and the subgroup that did not isolate MRSA; 91.9% (34/37) and 92.6% (50/54) respectively (chi2: 0.01; p= 0.97 CI95: 0.26-3.88). The main etiological agent was MRSA, and treatments should be adapted to this microorganism

Bacteriemia por Staphylococcus aureus con sensibilidad disminuida heterogénea a vancomicina: reporte de un caso / Staphylococcus aureus bacteremia with heterogeneous intermediate-level vancomycin resistance: a case report

Staphylococcus aureusmeticilina-resistente (SAMR)es una causa frecuente de bacteriemias intrahospitalarias. Para su tratamiento se utiliza vancomicina y han emergido cepas con sensibilidad disminuida heterogénea (h-VISA) que albergan subpoblaciones con sensibi-lidad reducida a vancomicina. Se comunica un caso de bacteriemia intra-tratamiento con vancomicina por SAMR h-VISA. El aislamiento muestra sensibilidad a vancomicina (CIMvan: 1 µg/mL), sin embargo E-test GRD sugiere h-VISA (CIMvan: 2 µg/mL y CIMtei: 8 µg/mL). El análisis del perfil poblacional - área bajo la curva (PAP-AUC) valida este hallazgo. Se rota a linezolid con resolución clínica.

Methicillin-resistant Staphylococcus aureus (SAMR) is a common cause of nosocomial bacteremia. Vancomycin, a glycopeptide, is widely employed for the therapy of SAMR infections. In recent years, heterogeneous vancomycin-intermediate strains (h-VISA) have emerged. We report a case of intra-treatment bacteremia caused by SAMR h-VISA. The isolate shows susceptibility to vancomycin (MICvan: 1 µg/mL). But the GRD E-test suggests h-VISA (MICvan: 2 µg/mL and MICtei: 8 µg/mL). The population analysis profile - area under the curve (PAP-AUC) validates SAMR h-VISA. Rotation of antibiotic therapy with linezolid is done, with good clinical outcome.

Caracterización fenotípica de variantes pequeñas de Staphylococcus aureus: un nuevo desafío / Phenotypic characterization of small colony variants of Staphylococcus aureus: a new challenge / Caracterizaçao fenotípica de pequenas variantes de Staphylococcus aureus: um novo desafio

En infecciones crónicas y recurrentes por Staphylococcus aureus se han descripto subpoblaciones de colonias pequeñas (VCPSa). El objetivo de este trabajo fue reconocer las características fenotípicas de VCPSa para optimizar su detección y caracterización a partir de materiales clínicos provenientes de infecciones crónicas. Se analizaron n=3 VCPSa de pacientes adultos con infecciones crónicas de tejidos blandos. Las muestras se inocularon en agar nutritivo, agar sangre, agar chocolate y agar Schaedler suplementado. Se realizaron tinción de Gram, catalasa, coagulasa libre, pruebas de dependencia para hemina, menadiona y timidina y, desarrollo/ataque del manitol en agar manitol salado. La sensibilidad antibiótica se efectuó en agar Mueller Hinton suplementado, según las pruebas de dependencia. Se investigó la presencia de proteína ligadora de penicilina anómala (PBP2´) por aglutinación con látex. Las VCPSa se detectaron en los medios de cultivo enriquecidos. Estas bacterias dieron positivas las pruebas de catalasa y coagulasa, y eran dependientes de menadiona y hemina. En los tres aislamientos se observó resistencia a cefoxitina y se detectó la PBP2´.

In chronic and recurrent infections, small colonies of Staphylococcus aureus subpopulations (SCVSa) have been observed. The objective of the present study was to recognize the phenotypic characteristics of SCVSa isolated from patients with chronic infections to optimize their detection. SCVSa of adult patients n=3 with chronic soft tissue infections were analyzed. Samples were inoculated on nutritive agar, blood-agar, chocolate agar and supplemented Schaedler agar. Subsequently, Gram stain, catalase, free coagulase, dependence tests for hemin, menadione and thymidine, and growth/fermentation of mannitol on salt mannitol agar were performed. Antibiotic susceptibility tests were performed by the agar diffusion method on supplemented Mueller Hinton agar, according to dependence assays results. Anomalous penicillin binding protein (PBP2') was investigated by latex agglutination. SCVSa were detected in all enriched culture media. They showed catalase and coagulase activities, and menadione and hemin dependence. By the agar diffusion test, cefoxitin resistance was found in all isolates; PBP2' was detected as well.

Nas infecções crônicas e recorrentes por Staphylococcus aureus, subpopulações de pequenas colônias (VCPSa) foram descritas. O objetivo desse trabalho foi reconhecer as características fenotípicas de VCPSa para otimizar sua detecção e caracterização a partir de materiais clínicos provenientes de infecções crônicas. Foram analisados n=3 VCPSa de pacientes adultos com infecções crônicas de tecidos moles. As amostras foram inoculadas em agar nutritivo, agar sangue; agar chocolate e agar Schaedler enriquecido. Foram realizados testes de coloração de Gram, catalase, coagulase livre, testes de dependência para hemina, menadiona e timidina, e desenvolvimento/fermentação do manitol em agar manitol salgado. A sensibilidade antibiótica foi realizada em agar Mueller Hinton suplementado, de acordo com os testes de dependência. Foi investigada a presença de proteína ligante de penicilina anômala (PBP2´) por aglutinação com látex. Os VCPSa foram detectados em meios de cultura enriquecidos. Estas bactérias deram positivas nos testes de catalase e coagulase positivos e eram dependentes de menadiona e hemina. A resistência à cefoxitina foi detectada nos três isolados e detectou-se a PBP2'.

Enterococcus spp. aislados de queso de oveja: resistencia a los antimicrobianos de utilización clínica / Enterococcus spp. isolated from goat cheese: resistance to clinically used antimicrobials

En Enterococcus spp. aislados de quesos de oveja se investigó la resistencia in vitro a antimicrobianos de utilización clínica. Se determinó la concentración inhibitoria mínima (CIM) para gentamicina, estreptomicina, vancomicina, teicoplanina, ampicilina, imipenem, linezolid y tigeciclina. Se detectó la producción de β-lactamasa y se realizaron experimentos de conjugación para transferir resistencia a gentamicina. En un aislamiento de E. faecalis y en 10 de E. faecium se observó resistencia a ampicilina; se demostró la producción de β-lactamasa en un E. faecalis. En E. faecium, 15 aislamientos fueron resistentes a imipenem; 4 a linezolid y 5 a glucopéptidos. En 4 aislamientos de E. faecalis se demostró alto nivel de resistencia plasmídica a gentamicina. No se observaron aislamientos resistentes a tigeciclina. El queso de oveja es un reservorio de enterococos resistentes con potencial diseminación al hombre a través de la cadena alimentaria.

In vitro resistance to clinically used antimicrobials was investigated in Enterococcus spp. isolated from goat cheese. The gentamycin, streptomycin, vancomycin, teicoplanin, ampicillin, imipenem, linezolid and tigecyclin minimum inhibitory concentration (MIC) was determined. Β-lactamase production was detected and conjugation experiments were carried out for transferring gentamycin resistance. In one E. faecalis and in 10 E. faecium isolates there was ampicillin resistance and β-lactamase production was demonstrated in one E. faecalis. Fifteen E. faecalis were imipenenem resistant; 4 linezolid resistant and 5 glucopeptide resistant. There was a high level of plasmidic resistance to tigecyclin in 4 E. faecalis isolates. There were no tigecyclin resistant isolates. Goat cheese is a reservoir of resistant enterococci with potencial human dissemination through the food chain.

Primer informe de celulitis cutánea por Erysipelothrix rhusiopathiae en dos trabajadores rurales / First report of cutaneous cellulitis caused by Erysipelothrix rhusiopathiae in two rural workers

Se informan dos casos de celulitis cutánea en trabajadores de un mismo criadero de aves a corral del área rural de la ciudad de Tandil, Argentina. En ambos pacientes fue identificado E. rhusiopathiae a partir de cultivos de muestras obtenidas por biopsia. La investigación del reservorio evidenció que en todas las muestras de las excretas de aves y en dos muestras de los residuos del alimento, se aisló E. rhusiopathiae con idéntico perfil bioquímico y de resistencia antimicrobiana al de las cepas aisladas de los dos casos clínicos. Si bien son necesarios estudios moleculares para establecer la relación epidemiológica entre las cepas aisladas de los pacientes y las del criadero, se puede inferir que la fuente de infección humana fue el criadero extensivo de aves de corral.

This report describes two cases of cutaneous cellulitis in workers at the same poultry farm in the rural area of Tandil, Argentina. In both patients E. rhusiopathiae was identified from culture samples obtained through biopsy. Investigation of the reservoir showed that, in all samples of fowl waste and in 2 samples of feed, E. rhusiopathiae was isolated with identical biochemical and antibiotic resistance profiles to those of the isolated strains in the case reports. Even though molecular analyses are required to establish an epidemiologic relation between the strains found in the patients and those on the farm, it can be inferred that the source of human infection was the extensive poultry farm.

In vitro and in vivo effects of Enterococcus faecalis CECT7121 on Toxocara canis

The aim of the present paper was to evaluate the larvicidal effect of Enterococcus faecalis CECT7121 (Ef7121) on the Toxocara canis cycle both in vitro and in vivo. For the in vitro experiments, T. canis larvae were incubated with the supernatants of Ef7121 (EI) and mutant Ef7121 (EIm), in a pre-culture of Ef7121 (EII) and in a fresh culture with Ef7121 (EIII) and the Ef7121 mutant strain (EIIIm). The viability of the larvae was calculated after a 48 h incubation. A significant reduction of the viability of T. canis larvae was observed in EI, EII and EIII. A decrease of this inhibitory effect was observed in EIm and EIIIm (p = 0.008). In the in vivo experiments, mice were orally inoculated with three doses of Ef7121. To study the probiotic persistence in the intestine, the animals were sacrificed every four days and their intestines were dissected. The initial average bacterial levels were 9.7 x 10(4) for Ef7121 (colony forming units/g). At the end of the assay the levels were 1.46 x 10(4). No bacterial translocation was detected in mesenteric lymphatic nodules and spleen. Ef7121 interference with the biological cycle was evaluated in mice challenged with T. canis. The interference was significant when the mice were challenged with probiotic and T. canis simultaneously (p = 0.001), but it was not significant when the challenge was performed 15 days after administration of the bacterial inoculum (p = 0.06). In conclusion, Ef7121 possessed in vitro and in vivo larvicidal activity.

Adult bacteremic pneumococcal pneumonia acquired in the community. Aprospective study on 101 patients

Our objective was to describe incidence, clinical, radiographic and microbiological features of bacteremic pneumococcal pneumonia (BPP) in our environment. A total of 101 patients (7 were treated as outpatients), older than 18 years of age suffering BPP were prospectively evaluated. The incidence was 2.8 cases per 1000 admissions, 50 were males, mean age was 59.9 years (19-97), mortality was 11.8%. Eighty three percent of fatalities occurred within 3 days of admission. Mortality rate increased with advancing age. Fever, cough and chest pain were the commonest presenting symptoms and 44% of patients had extrapulmonary manifestations. Cigarette smoking, chronic obstructive lung disease, alcoholism and congestive heart failure (CHF) were the commonest underlying conditions. CHF was more frequent in non-survivors (p = 0.002). A lobar pattern at chest radiograph predominated in survivors and a diffuse pattern in non-survivors (p = 0.007). Pleural effusion (20.7%), empyema (7.9%) and respiratory failure (7.9%) were the main complications. Underlying diseases were present in 100% of non-survivors (p = 0.03). Ninety four percent of patients were treated with beta-lactam antibiotics. Streptococcus pneumoniae was isolated from sputum in 6 cases. Three out of 101 S. pneumoniae isolates recovered from blood samples (one from each patient) presented organisms resistant to penicillin. We observed an incidence of BPP that is similar to the observed in other countries. There are clinical and radiographic differences between survivors and non-survivors. Penicillin-resistant S. pneumoniae is still an unusual problem in our area

Meningitis a enterococcus faecalis / Meningitis due to Enteroccocus faecalis

Enterococcus faecalis meningitis is an infrequent entity that accounts for less than 1 percent of all suppurative meningitis in the adult. Usually, this infection affects patients with compromised host defenses or those who have congenital or acquired CNS lesions mainly as intrahospitalary infections. An 85 year old woman from our community (Tandil county) without any predisposed condition, was admitted in the hospital in an unconscious state (grade 3 Glasgow's index), meningeal signs and purulent CSF, from which E. faecalis was isolated. The patient was treated with IV Ampicillin and Gentamycin (17 days), intrathecal Gentamycin (4 days) and ]V dexametasona (6 days). The clinical and bacteriological remission was achieved, without any sequel or relapse during 2 years follow up.