A hospital-based matched case-control study to identify clinical outcome and risk factors associated with carbapenem-resistant Klebsiella pneumoniae infection

Background: Healthcare-associated infections caused by Klebsiella pneumoniae isolates are increasing and few effective antibiotics are currently available to treat patients. We observed decreased carbapenem susceptibility among K. pneumoniae isolated from patients at a tertiary private hospital that showed a phenotype compatible with carbapenemase production although this group of enzymes was not detected in any sample. the aim of this study was to describe the epidemiology and clinical outcomes associated with carbapenem-resistant K. pneumoniae and to determine the antimicrobial resistance mechanisms.Methods: Risk factors associated with carbapenem-resistant K. pneumoniae infections were investigated by a matched case-control study from January 2006 through August 2008. A cohort study was also performed to evaluate the association between carbapenem resistance and in-hospital mortality. Bacterial identification and antimicrobial susceptibility were determined by Vitek 2 and Etest. Carbapenemase activity was detected using spectrophotometric assays. Production of beta-lactamases and alterations in genes encoding K. pneumoniae outer membrane proteins, OmpK35 and OmpK36, were analyzed by PCR and DNA sequencing, as well as SDS-Page. Genetic relatedness of carbapenem resistant isolates was evaluated by Pulsed Field Gel Electrophoresis.Results: Sixty patients were included (20 cases and 40 controls) in the study. Mortality was higher for patients with carbapenem-resistant K. pneumoniae infections compared with those with carbapenem-susceptible K. pneumoniae (50.0% vs 25.7%). the length of central venous catheter use was independently associated with carbapenem resistance in the multivariable analysis. All strains, except one, carried bla(CTX-M-2), an extended-spectrum betalactamase gene. in addition, a single isolate also possessed bla(GES-1). Genes encoding plasmid-mediated AmpC beta-lactamases or carbapenemases (KPC, metallo-betalactamases or OXA-carbapenemases) were not detected.Conclusions: the K. pneumoniae multidrug-resistant organisms were associated with significant mortality. the mechanisms associated with decreased K. pneumoniae carbapenem susceptibility were likely due to the presence of cephalosporinases coupled with porin alterations, which resulted from the presence of the insertion sequences in the outer membrane encoding genes.Instituto Israelita de Ensino e Pesquisa Israelita Albert EinsteinHosp Israelita Albert Einstein, Infect Control Unit, BR-05652000 São Paulo, BrazilHosp Israelita Albert Einstein, Microbiol Lab, BR-05651901 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP EPM, Div Infect Dis, BR-04024002 São Paulo, BrazilHosp Israelita Albert Einstein, Intens Care Unit, BR-05651901 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP EPM, Div Infect Dis, BR-04024002 São Paulo, BrazilInstituto Israelita de Ensino e Pesquisa Israelita Albert Einstein: 449.08Web of Scienc

Correlation between mass and volume of collected blood with positivity of blood cultures

Background The collection of blood cultures is an extremely important method in the management of patients with suspected infection. Microbiology laboratories should monitor blood culture collection. Methods Over an 8-month period we developed a prospective, observational study in an adult Intensive Care Unit (ICU). We correlated the mass contained in the blood vials with blood culture positivity and we also verified the relationship between the mass of blood and blood volume collected for the diagnosis of bloodstream infection (BSI), as well as we explored factors predicting positive blood cultures. Results We evaluated 345 patients with sepsis, severe sepsis or septic shock for whom blood culture bottles were collected for the diagnosis of BSI. Of the 55 patients with BSI, 40.0 % had peripheral blood culture collection only. BSIs were classified as nosocomial in 34.5 %. In the multivariate model, the blood culture mass (in grams) remained a significant predictor of positivity, with an odds ratio 1.01 (i.e., for each additional 1 mL of blood collected there was a 1 % increase in positivity; 95 % CI 1.01–1.02, p = 0.001; Nagelkerke R Square [R2] = 0.192). For blood volume collected, the adjusted odds ratio was estimated at 1.02 (95 % CI: 1.01–1.03, p \u3c 0.001; R2 = 0.199). For each set of collected blood cultures beyond one set, the adjusted odds ratio was estimated to be 1.27 (95 % CI: 1.14–1.41, p \u3c 0.001; R2 = 0.221). Conclusions Our study was a quality improvement project that showed that microbiology laboratories can use the weight of blood culture bottles to determine if appropriate volume has been collected to improve the diagnosis of BSI

MALDI-TOF MS in the clinical microbiology laboratory

Traditional methods for microbial identification are often very laborious and time consuming. A new mass spectrometry based technique, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF), has been described as a rapid, practical and low-cost method for this purpose. In this article, primary and possible future applications of this tool are briefly discussed

Prevalence of upper respiratory tract infections at a tertiary care hospital in the city of São Paulo

Objective: To evaluate the prevalence of pathogens in the upper respiratory tract according to age at a tertiary care hospital in the city of São Paulo. Methods: A total of 6,144 biological material tests from upper respiratory airways were analyzed: 740 bacterial cultures, 726 virus screenings and 4,678 rapid tests for S. pyogenes. Results: The most frequently found etiological agent was respiratory syncytial virus (29.6%; 215/726). The main agents detected per age groups were: respiratory syncytial virus (25.34%; 184/726) in patients aged 28 days-3 years; S. pyogenes (9.5%; 70/740) in 3-12 year-old children; influenza virus (8.8%; 64/726) in adults (18-59 years). Conclusions: The etiologic agents of upper respiratory infections vary according to age and imply diverse clinical and therapeutic management

Comparison of agents and sensitivity profile in urinary tract infection in diabetic and non-diabetic patients

Objective: To study diabetic and non diabetic patients in UTI, regardingthe prevalence of broad spectrum beta-lactamase producing pathogensand quinolone resistance. Methods: Inclusion criteria for this studywas the presence of positive urine culture and fasting glucose equal toor above 126 mg/dl and below 100 mg/dl. We managed to include 494patients, 210 diabetics and 284 non-diabetics. Results: Escherichiacoli was the most frequently found pathogen in both diabetic andnon-diabetic groups, and significantly more frequent in non diabeticpatients (p = 0.0001) – 60% to 31% when compared to their diabeticcounterparts. Candida albicans infecting the urinary tract was foundin 30% of diabetics and in 16% of non-diabetics (p = 0.003). Broadspectrum beta-lactamase production was more frequently present inKlebsiella pneumoniae, however without significant difference betweenthe groups. Broad spectrum beta-lactamase production was morefrequent in diabetic patients (12%) than in non-diabetics (4%) (p =0.03). Quinolones resistance was more common in diabetics (40%)when compared to non-diabetics (14%) (p = 0.0001). Escherichiacoli is one of the pathogens more frequently found in patients withUTI. Conclusion: Diabetics have a greater likelihood of developingfungal urinary tract infection by Candida albicans, have more broadspectrum beta-lactamase producing Escherichia coli and more quinolone-resistant pathogens

Rothia aeria endocarditis in a patient with a bicuspid aortic valve: case report

Rothia aeria is an uncommon pathogen mainly associated with endocarditis in case reports. In previous reports, endocarditis by R. aeria was complicated by central nervous system embolization. In the case we report herein, endocarditis by R. aeria was diagnosed after acute self-limited diarrhea. In addition to the common translocation of R. aeria from the oral cavity, we hypothesize the possibility of intestinal translocation. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and genetic sequencing are important tools that can contribute to early and more accurate etiologic diagnosis of severe infections caused by Gram-positive rods

Diagnóstico de infecção por Candida: avaliação de testes de identificação de espécies e caracterização do perfil de suscetibilidade

INTRODUÇÃO: Infecções invasivas provocadas por Candida são importantes causas de morbidade e mortalidade. O sucesso do tratamento dessas infecções depende da identificação da espécie e do padrão de sensibilidade aos antifúngicos. Portanto, diagnóstico rápido e específico é fundamental para a precoce introdução de terapêutica adequada. OBJETIVOS: Avaliar diferentes métodos diagnósticos de determinação de espécies de Candida e caracterizar, entre as espécies identificadas, o padrão de sensibilidade aos diferentes antifúngicos. MATERIAL E MÉTODOS: A identificação das espécies de Candida presentes em amostras de diferentes materiais biológicos foi realizada pelo cultivo em CHROMagar® Candida e pela técnica de reação em cadeia da polimerase tipo Nested (N-PCR). O padrão de sensibilidade das amostras foi avaliado pela utilização de Etest®. RESULTADO: CHROMagar® caracterizou 50% das amostras como Candida albicans; 20,8%, Candida tropicalis; 2,4%, Candida krusei e 26,9%, outras espécies (não determinadas). As cepas de C. albicans e C. tropicalis foram caracterizadas por CHROMagar® e N-PCR. Porém cepas de outras espécies, indeterminadas em CHROMagar®, caracterizaram-se como C. parapsilosis em N-PCR. Cepas de C. krusei e C. tropicalis apresentaram perfil de resistência a, respectivamente, fluconazol e 5-fluocitosina. Quanto ao itraconazol, observou-se padrão de resistência em cepas de C. albicans e C. tropicalis. DISCUSSÃO: As técnicas metodológicas utilizadas são de fácil reprodutibilidade e alta especificidade, fornecendo diagnóstico complementar, e o emprego do Etest® viabiliza a precoce introdução de tratamento específico. CONCLUSÃO: O crescente aparecimento de espécies de Candida resistentes aos azólicos confirma a importância de monitorar possíveis mudanças na distribuição das espécies patogênicas e dos padrões de sensibilidade