Proposal of a clinical score to stratify the risk of multidrug-resistant gram-negative rods bacteremia in cancer patients

ABSTRACT Introduction: Multidrug-resistant gram-negative rods (MDR GNR) represent a growing threat for patients with cancer. Our objective was to determine the characteristics of and risk factors for MDR GNR bacteremia in patients with cancer and to develop a clinical score to predict MDR GNR bacteremia. Material and Methods: Multicenter prospective study analyzing initial episodes of MDR GNR bacteremia. Risk factors were evaluated using a multiple logistic regression (forward-stepwise selection) analysis including variables with a p < 0.10 in univariate analysis. Results: 394 episodes of GNR bacteremia were included, with 168 (42.6 %) being MDR GNR. Five variables were identified as independent risk factors: recent antibiotic use (OR = 2.8, 95 % CI 1.7-4.6, p = 0.001), recent intensive care unit admission (OR = 2.9, 95 % CI 1.1-7.8, p = 0.027), hospitalization ≥ 7 days prior to the episode of bacteremia (OR = 3.5, 95 % CI 2-6.2, p = 0.005), severe mucositis (OR = 5.3, 95 % CI 1.8-15.6, p = 0.002), and recent or previous colonization/infection with MDR GNR (OR = 2.3, 95 % CI 1.2-4.3, p = 0.028). Using a cut-off value of two points, the score had a sensitivity of 66.07 % (95 % CI 58.4-73.2 %), a specificity of 77.8 % (95 % CI 71.4-82.7 %), a positive predictive value of 68 % (95 % CI 61.9-73.4 %), and a negative predictive value of 75.9 % (95 % CI 71.6-79.7 %). The overall performance of the score was satisfactory (AUROC 0.78; 95 % CI 0.73-0.82). In the cases with one or none of the risk factors identified, the negative likelihood ratio was 0.18 and the post-test probability of having MDR GNR was 11.68 %. Conclusions: With the growing incidence of MDR GNR as etiologic agents of bacteremia in cancer patients, the development of this score could be a potential tool for clinicians.

Microbiota periodontal y microorganismos aislados de válvulas cardiacas en pacientes sometidos a cirugía de reemplazo de válvulas en una clínica de Cali, Colombia / Periodontal microbiota and microorganisms isolated from heart valves in patients undergoing valve replacement surgery in a clinic in Cali, Colombia

Resumen Introducción. La periodontitis es una enfermedad infecciosa que afecta los tejidos de soporte del diente y se asocia con diferentes enfermedades sistémicas, incluida la enfermedad cardiovascular. Los estudios microbiológicos permiten detectar microorganismos a partir de muestras subgingivales y cardiovasculares. Objetivo. Describir la microbiota periodontal cultivable y la presencia de microorganismos en válvulas cardiacas de pacientes sometidos a cirugía de reemplazo valvular en una clínica de Cali. Materiales y métodos. Se analizaron 30 muestras subgingivales y de tejidos valvulares mediante cultivo en medio bifásico, agar de sangre con suplemento y agar tripticasa de soya con antibiótico. Las muestras de las válvulas se analizaron mediante reacción en cadena de la polimerasa (PCR) convencional. Resultados. Los patógenos periodontales aislados de bolsas periodontales fueron Fusobacterium ( 50 % ), Prevotella intermedia/nigrescens (40 %), Campilobacter rectus (40 %), Eikenella corrodens (36,7 %), bacilos entéricos Gram negativos (36,7 %), Porphyromonas gingivalis (33,3 %) y Eubacterium (33,3 %). Los agentes patógenos aislados de la válvula aórtica fueron Propionibacterium acnes (12 %), bacilos entéricos Gram negativos (8 %), Bacteroides merdae (4 %) y Clostridium bifermentans (4 %), y de la válvula mitral, P. acnes y Clostridium beijerinckii. La PCR convencional no arrojó resultados positivos para agentes patógenos orales y solo se detectó ADN bacteriano en dos muestras. Conclusiones. La microbiota periodontal de pacientes sometidos a cirugía de reemplazo valvular estaba conformada por especies Gram negativas que han sido relacionadas con infecciones en tejidos extraorales; sin embargo, no se encontraron agentes patógenos periodontales en los tejidos de las válvulas. Aunque hubo muestras de estos tejidos y subgingivales, positivas para bacilos entéricos Gram negativos, no es posible asegurar que tuvieran el mismo origen filogenético.

Abstract Introduction: Periodontitis is an infectious disease that affects the support tissue of the teeth and it is associated with different systemic diseases, including cardiovascular disease. Microbiological studies facilitate the detection of microorganisms from subgingival and cardiovascular samples. Objective: To describe the cultivable periodontal microbiota and the presence of microorganisms in heart valves from patients undergoing valve replacement surgery in a clinic in Cali. Materials and methods: We analyzed 30 subgingival and valvular tissue samples by means of twophase culture medium, supplemented blood agar and trypticase soy agar with antibiotics. Conventional PCR was performed on samples of valve tissue. Results: The periodontal pathogens isolated from periodontal pockets were: Fusobacterium nucleatum (50%), Prevotella intermedia/ nigrescens (40%), Campylobacter rectus (40%), Eikenella corrodens (36.7%), Gram negative enteric bacilli (36.7%), Porphyromonas gingivalis (33.3%), and Eubacterium spp. (33.3%). The pathogens isolated from the aortic valve were Propionibacterium acnes (12%), Gram negative enteric bacilli (8%), Bacteroides merdae (4%), and Clostridium bifermentans (4%), and from the mitral valve we isolated P. acnes and Clostridium beijerinckii. Conventional PCR did not return positive results for oral pathogens and bacterial DNA was detected only in two samples. Conclusions: Periodontal microbiota of patients undergoing surgery for heart valve replacement consisted of species of Gram-negative bacteria that have been associated with infections in extraoral tissues. However, there is no evidence of the presence of periodontal pathogens in valve tissue, because even though there were valve and subgingival samples positive for Gram-negative enteric bacilli, it is not possible to maintain they corresponded to the same phylogenetic origin.

Bacteriemia por Ralstonia pickettii en pacientes en hemodiálisis: reporte de dos casos / Ralstonia pickettii bacteremia in hemodialysis patients: a report of two cases

RESUMEN Ralstonia pickettii es un bacilo gram negativo de baja virulencia que puede asociarse a infecciones relacionadas a los cuidados de la salud y provocar bacteriemias. La bacteriemia por Ralstonia pickettii es poco frecuente pero se relaciona con la contaminación de productos de uso médico principalmente en pacientes inmunodeprimidos. Presentamos dos casos en pacientes en hemodiálisis crónica vinculados a contaminación del agua de diálisis. Se han publicado casos similares vinculados a la administración de fluídos intravenosos, ampollas de medicación, asociado a membranas de circulación extracorpórea, entre otros. La detección de una bacteriemia por Ralstonia pickettii, debe sospechar e iniciar la búsqueda de productos de uso médico contaminados, fluídos y/o medicación.

ABSTRACT Ralstonia pickettii is a low-virulence gram-negative bacillus that may be associated with infections related to health care and may cause bacteremia. Ralstonia pickettii bacteremia is uncommon but is related to the contamination of medical products, mainly in immunodepressed patients. We present two cases of patients on chronic hemodialysis with Ralstonia pickettii bacteremia linked to contamination of the dialysis water. Similar cases have been published with links to intravenous fluid administration, medication ampules, and the use of extracorporeal oxygenation membranes, among other factors. The detection of Ralstonia pickettii bacteremia should provoke suspicion and a search for contaminated medical products, fluids, and/or medications.

Endocarditis infecciosa por Rhizobium radiobacter: Reporte de un caso / Infective endocarditis by Rhizobium radiobacter: A case report

Rhizobium radiobacter es una bacteria Gram-negativa, fijadora de nitrógeno que se encuentra principalmente en el suelo. Rara vez causa infecciones en humanos. Ha sido asociada a bacteriemia secundaria a colonización de catéteres intravasculares en pacientes inmunocomprometidos. El objetivo de este trabajo es informar un caso de endocarditis infecciosa por R. radiobacter. Se trata de paciente masculino, de 47 años de edad, con diagnóstico de enfermedad renal crónica estadio 5 en tratamiento sustitutivo con hemodiálisis, quien acude a centro asistencial por presentar fiebre de dos semanas de evolución. Es hospitalizado, se toman muestras de sangre periférica para hemocultivo y se inicia antibioticoterapia empírica con cefotaxime más vancomicina. El ecocardiograma transtorácico revelo vegetación fusiforme en válvula tricúspide con regurgitación grado III-IV/IV. Al séptimo día del inicio de la antibioterapia el paciente presenta mejoría clínica y paraclínica. La bacteria identificada por hemocultivo es Rhizobium radiobacter resistente a ceftriaxona y sensible a imipenem, amikacina, ampicilina y ampicilina/sulbactam. Debido a la mejoría clínica se decide continuar tratamiento con vancomicina y se anexa imipenem. A los 14 días de iniciada la antibioterapia el paciente es dado de alta con tratamiento ambulatorio con imipenen hasta cumplir seis semanas de tratamiento. En el ecocardiograma control se evidencio ausencia de la vegetación en la válvula tricúspide. Este caso sugiere que R. radiobacter puede ser una causa de endocarditis en pacientes portadores de catéteres intravasculares.

Rhizobium radiobacter is a Gram-negative, nitrogen-fixing bacterium, which is found mainly on the ground. It rarely causes infections in humans. It has been associated with bacteremia, secondary to colonization of intravascular catheters, in immunocompromised patients. The aim of this paper was to report the case of an infective endocarditis caused by R. radiobacter, in a 47-year-old male, diagnosed with chronic kidney disease stage 5, on replacement therapy with hemodialysis and who attended the medical center with fever of two weeks duration. The patient was hospitalized and samples of peripheral blood were taken for culture. Empirical antibiotic therapy was started with cefotaxime plus vancomycin. The transthoracic echocardiogram revealed fusiform vegetation on the tricuspid valve, with grade III-IV/IV regurgitation. On the seventh day after the start of antibiotic therapy, the patient had a clinical and paraclinical improvement. The bacterium identified by blood culture was Rhizobium radiobacter, ceftriaxone-resistant and sensitive to imipenem, amikacin, ampicillin and ampicillin/ sulbactam. Because of the clinical improvement, it was decided to continue treatment with vancomycin and additionally, with imipenem. At 14 days after the start of antibiotic therapy, the patient was discharged with outpatient treatment with imipenem up to six weeks of treatment. The control echocardiogram showed the absence of vegetation on the tricuspid valve. This case suggests that R. radiobacter can cause endocarditis in patients with intravascular catheters.

Aislamientos bacterianos de muestras respiratorias de pacientes pediátricos con fibrosis quística y su distribución por edades / [Bacterial isolates from respiratory samples of pediatric patients with cystic fibrosis and their distribution by ages].

The bacterial isolates from respiratory samples of 50 pediatric patients with cystic fibrosis, their distribution by ages and antimicrobial resistance pattern as well as the intermittence of isolations and coinfections, were investigated. Staphylococcus aureus was isolated in 72

of patients, followed by Pseudomonas aeruginosa (58

), and the Burkholderia cepacia complex (12

). The frequency of resistance of P. aeruginosa isolates to ß-lactam antibiotics was low (13.8

). Fifty percent of S. aureus isolates was methicillin-resistant, and 57.1

of H. influenza was ampicillin resistant due to ß-lactamase production. In children under 4 years-old, S. aureus was predominant, followed by P. aeruginosa and H. influenzae. This order of predominance was observed in all the groups studied, except in that of children between 10 and 14 years-old. Stenotrophomonas maltophilia and Achromobacter xylosoxidans isolates were intermittent and accompanied by other microorganisms. Finally, we observed a great variety of bacterial species, which imposes stringent performance requirements for microbiological studies in all respiratory samples of these patients.

Evolución clínica y de laboratorio de episodios de neutropenia febril en niños con cáncer, en un hospital de Colombia, período 2007-2009 / Clinical and laboratory evolution of the febrile neutropenia episodes in pediatric patients hospitalized in a Colombian hospital in 2007-2009

Introduction: Neutropenia is one of the most common complications in children with cancer, and it's the most important parameter to determine infection risk. In neutropenic patients the signs and symptoms could be scarce and in occasions fever could be the only symptom. For these reasons all patients with febrile neutropenia (FN) should be considered as if they had a possibly severe disease. Aim: To describe the clinical characteristics and laboratory parameters observed in cancer patients with FN attended at our hospital to perform a more rational management of this complication in the future. Patients and Methods: The clinical files accumulated during 36 months, belonging to patients aged 0 to 15 years that were hospitalized because of cancer and FN were reviewed. Results: In this series the source of fever was found in 48.6% of 105 NF episodes, and bacteria were isolated from blood or urine culture in 38%. The most frequent bacterial species recovered were methicillin susceptible S. aureus (20.8%) and ESBL negative E. coli (20.8%). Piperacillin/tazobactam was the most used first line antibiotic prescribed (87.6%) and meropenem was the second choice (18%). Granulocyte colony stimulating factor was used in 61.9% of the cases and episodes mortality rate was 6.7%. Conclusion: Clinical characteristics and bacteriological findings in our institution do not differ significantly from what has been described for pediatric cancer patients in other series.

Introducción: La neutropenia es una de las complicaciones más comunes en los niños con cáncer y el principal parámetro para determinar el riesgo de infección. Además, en estos pacientes los signos clínicos de infección pueden ser escasos y en ocasiones la fiebre es la única manifestación, por lo que todo paciente neutropénico y febril se debe manejar como si presentara una posible infección grave. Objetivo: Describir el comportamiento clínico y de laboratorio de los pacientes con neutropenia febril (NF) atendidos en nuestra institución para racionalizar el manejo futuro de esta complicación. Pacientes y Métodos : Se revisó los registros clínicos acumulados durante un período de 36 meses, de todos los pacientes de 0 a 15 años internados por cáncer y NF. Resultados: En este estudio se encontró el foco infeccioso en 48,6% de 105 episodios y se logró aislamiento bacteriano por hemocultivos y/o urocultivo en 38%. Las bacterias encontradas con mayor frecuencia fueron S. aureus sensible a meticilina (20,8%) y E. coli no productora de BLEE (20,8%). El antimicrobiano de primera línea más usado fue piperacilina/tazobactam (87,6%) y de segunda línea meropenem (18%). Se usó factor estimulante de colonias de granulocitos en 61,9% de los pacientes. La mortalidad asociada a estos episodios fue de 6,7%. Conclusión: Las características clínicas y hallazgos de laboratorio en nuestra institución no difieren mayormente de lo descrito en población pediátrica en otras series.

Bacteriemia en daño hepático crónico / Bacteremia in patients with liver cirrhosis

Las infecciones bacteriémicas son más frecuentes en el paciente cirrótico que en la población general. Se identificaron retrospectivamente 59 pacientes cirróticos con bacteriemia, hospitalizados entre los años 2005 y 2008. La bacteriemia sin foco fue la más frecuente (29 por ciento), seguida de aquellas de origen pulmonar (22 por ciento). Cincuenta y dos por ciento de los agentes aislados correspondieron a cocáceas grampositivas y 48 por ciento a bacilos gramnegativos, siendo estos últimos los agentes predominantes en las bacteriemias nosocomiales. Los principales agentes aislados fueron Staphylococcns aureus (24 por ciento) y Escherichia col i (22 por ciento). La mortalidad de los pacientes cirróticos bacteriémicos fue mayor que la del total de cirróticos hospitalizados (37 vs 9,4 por ciento; p < 0,001) y la medición del puntaje de MELD a las 72 horas se correlacionó significativamente con la mortalidad. Conclusión: La bacteriemia es una complicación grave del paciente cirrótico y el MELD podría ser útil en su categorización de riesgo.

Bacteremic infections are more frequent in patients with cirrhosis, as their immune system is compromised. Series of cirrhotic patients with bacteremia has seldom been reported in Chile. We retrospectively collected, from 2005 to 2008, 59 episodes of bacteremia in cirrhotics representing 9 percent of the overall number of bacteremic episodes seen in our center in the period. Spontaneous bacteremia accounted for 29 percent followed by those of pulmonary origin (22 percent). Grampositive cocci and gramnegative bacilli were responsible in 52 percent and 48 percent respectively, however gramnegative rods predominated in nosocomial bacteremias. Overall, the most frequent organisms were Staphylococcus aureus (24 percent) and Escherichia col i (22 percent). Mortality in bacteremic patients was significantly higher compared with all cirrhotic patients hospitalized in the period (37.0 vs 9.4 percent; p < 0.001) and MELD score was significantly correlated with mortality. Conclusion: bacteremia is a severe complication of cirrhosis and MELD score could be a useful tool to stratify risk in these patients.

Risk factors for Hospital-Acquired Pneumonia in nonventilated adults

Although most recent publications focus on Ventilator-associated Pneumonia, Non-Ventilator-associated Hospital-acquired pneumonia (NVHAP) is still worrisome. We studied risk factors for NVHAP among patients admitted to a small teaching hospital. Sixty-six NVHAP case patients and 66 controls admitted to the hospital from November 2005 through November 2006 were enrolled in a case-control study. Variables under investigation included: demographic characteristics, comorbidities, procedures, invasive devices and use of medications (Sedatives, Antacids, Steroids and Antimicrobials). Univariate and multivariable analysis (hierarchical models of logistic regression) were performed. The incidence of NVHAP in our hospital was 0.68 percent (1.02 per 1,000 patients-day). Results from multivariable analysis identified risk factors for NVHAP: age (Odds Ratio[OR]=1.03, 95 percent Confidence Interval[CI]=1.01-1.05, p=0.002), use of Antacids (OR=5.29, 95 percentCI=1.89-4.79, p=0.001) and Central Nervous System disease (OR=3.13, 95 percentCI=1.24-7.93, p=0.02). Although our findings are coherent with previous reports, the association of Antacids with NVHAP recalls a controversial issue in the physiopathology of Hospital-Acquired Pneumonia, with possible implications for preventive strategies.

Oligella urethralis isolada em hemocultura de paciente internada no complexo HSP/UNIFESP / Oligella urethralis isolated in hemoculture from patient interned in HSP-UNIFESP complex

Primeiro isolado de Oligella urethralis em duas amostras de sangue periférico detectado por metodologia de monitoração contínua de metabolismo (sistema Bactec®) e identificado pelo sistema automatizado Phoenix® (BD System) em paciente com linfoma retroperitoneal com metástase em sistema nervoso central (SNC) no Hospital São Paulo da Universidade Federal de São Paulo (HSP/UNIFESP).

First time isolation of Oligella urethralis in two samples of peripheral blood detected by continuous metabolism monitoring methodology (Bactec 61650 system) and identified by the automatized Phoenix 61650 system (BD System) in patient with retro-peritoneal lymphoma with metastasis in the central nervous system at São Paulo hospital of Federal University of São Paulo (HSP/UNIFESP).

Gastritis flegmonosa: caso clínico y revisión de la literatura / Phlegmonous gastritis: case report and review of the literature

Phlegmonous gastritis in an infrequent condition with high mortality characterized by suppurative infection of the gastric wall as a consecuence of a localized or hematogenous infection. The clinical and laboratory findings are nonsoecific and the endoscopy and endosonography are the methods of choice for the diagnosis. The treatment should by prompt and sometimes requires antibiotic therapy in association with gastric resection. In this report we present a case of phlegmonous gastritis as a complication of an endoscopic procedure.

Biofilm formation by Stenotrophomonas maltophilia isolates from device-associated nosocomial infections / Formación de biopelículas por aislamientos de Stenotrophomonas maltophilia recuperados de infecciones nosocomiales asociadas al uso de dispositivos médicos

Medical devices are often colonized by bacteria which may cause severe infections. The aim of this work was to evaluate biofilm formation by S. maltophilia isolates from device-associated nosocomial infections. The 13 local isolates exhibited different capacities of biofilm formation on hydrophilic and hydrophobic surfaces. All isolates formed strong biofilms in polystyrene microplates, while strong, moderate or weak biofilms were detected in borosilicate (BS) or polypropylene (PP) tubes. The proficiency of biofilm formation was better evaluated by the level of crystal violet staining expressed relative to the final culture density. The microscopic analysis of biofilms formed on glass coverslips revealed the presence of a matrix of exopolysaccharides and microcolonies typical of biofilm architecture. Isolates with increased adhesion to BS showed larger microcolonies. According to our results, twitching correlated well with attachment to the three abiotic surfaces tested, while swimming only showed a slight correlation with biofilm formation on PP. Poor correlation was observed between cell surface hydrophobicity and biofilm formation. One of the highest biofilm-producing isolates adhered to urethral catheters of different materials, and exhibited an increased resistance to oxidative stress, one of the common stresses encountered by bacteria during the infection process due to the immune response.

El objetivo de este trabajo fue evaluar la formación de biopelículas por parte de aislamientos de Stenotrophomonas maltophilia. Los 13 aislamientos locales evaluados mostraron diferente capacidad de formar biopelículas en superficies hidrofílicas e hidrofóbicas. Todos ellos formaron biopelículas fuertes en microplacas de poliestireno (PS), mientras que se observaron biopelículas fuertes, moderadas o débiles en tubos de borosilicato (BS) o polipropileno (PP). La medida del cristal violeta unido a la biopelícula expresada en función de la densidad final de los cultivos permitió una mejor evaluación de la eficiencia de formación de biopelículas. El análisis microscópico de biopelículas formadas sobre cubreobjetos mostró la presencia de una matriz de exopolisacáridos y microcolonias típicas de la arquitectura de las biopelículas. Los aislamientos con mayor adhesión a BS mostraron microcolonias de mayor tamaño. La motilidad asociada a superficies ( twitching) presentó buena correlación con la adhesión a BS, PP y PS, mientras que la motilidad asociada a flagelos solo correlacionó ligeramente con la adhesión a PP. La correlación entre la hidrofobicidad de la superficie bacteriana y la formación de biopelículas fue escasa. Uno de los aislamientos productores de biopelículas fuertes evidenció capacidad de adhesión a catéteres uretrales de diferentes materiales y mayor resistencia al estrés oxidativo.

Nosocomial outbreak of Pantoea agglomerans in a pediatric urgent care center

Pantoea agglomerans is a Gram-negative bacterium whose isolates can be found in blood cultures and other secretions. This article described one outbreak of sepsis due to this bacterium in the pediatric urgent care center of a tertiary hospital, in Brasilia, Federal District. This was a case-control study and it evaluated the risk factors for acquisition of nosocomial sepsis caused by Pantoea agglomerans. Six case-patients and 15 control-patients have been found. The risk factors were: vomiting in the internment and presence of solution compositions in the intravenous hydration therapy received in bigger number than 2 compositions. The transference tube used for the compositions was contaminated with Pantoea agglomerans, characterizing the outbreak with common source. The evolution of all the patients was favorable.

Infections related to vascular catheters in a pediatric intensive care unit.

We determined the rate and risk factors for colonization of 103 peripheral intravenous catheter and 32 central venous catheters. 52.5% peripheral catheters had colonization. Common organisms isolated were Pseudomonas (33.3%) and coagulase negative Staphylococci (29.6%). Colonization was higher in catheters inserted in the lower limb. Overall 62.5% of the central catheters were colonized, chiefly by coagulase negative Staphylococci, Pseudomonas and Candida. All central catheters in place for more than 11 days were colonized. Subclavian vein catheters had a higher rate (68.2%) of colonization in comparison to femoral vein insertions (40%). We conclude that upper limb placements are preferable to lower limbs when using peripheral lines. Changing peripheral intravenous catheters every 48 hours and central venous catheters every 10 days may decrease the rate of colonization.

A Case of Chromobacterium Infection after Car Accident in Korea

Chromobacterium violaceum is a gram negative straight rod, 0.8-1.2 by 2.5 to 6.0 m, which is motile by one polar flagella and one to four lateral flagella. The organism inhabits soil and water and is often found in semitropical and tropical climates. Infections in humans are rare. We report a case of infection caused by strains of C. violaceum. A 38-year-old male patient was admitted to KyungHee University Hospital, Seoul, Korea on July 28th, 2003, after a car accident. The patient had multiple trauma and lacerations. He had an open wound in the left tibial area from which C. violaceum was isolated. The strain was resistant to ampicillin, tobramycin, ampicillin/sulbactam, ceftriaxone and cefepime, but was susceptible to amikacin, gentamicin, ciprofloxacin, levofloxacin, trimethoprim/sulfamethoxazole and piperacillin/tazobactam. The patient was treated successfully by debridement, cephapirin sodium and astromicine sulfate.