Urinary Tract Infections in Kidney Transplant Patients Due to Escherichia coli and Klebsiella pneumoniae-Producing Extended-Spectrum ß-Lactamases: Risk Factors and Molecular Epidemiology.

Urinary tract infection (UTI) is a common complication after kidney transplantation, often associated to graft loss and increased healthcare costs. Kidney transplant patients (KTPs) are particularly susceptible to infection by Enterobacteriaceae-producing extended-spectrum ß-lactamases (ESBLs). A retrospective case-control study was conducted to identify independent risk factors for ESBL-producing Escherichia coli and Klebsiella pneumoniae in non-hospitalized KTPs with UTI. Forty-nine patients suffering from UTI by ESBL-producing bacteria (ESBL-P) as case group and the same number of patients with UTI by ESBL negative (ESBL-N) as control-group were compared. Clinical data, renal function parameters during UTI episodes, UTI recurrence and relapsing rate, as well as risk factors for recurrence, molecular characterization of isolates and the respective antimicrobial susceptibility profile were evaluated. Diabetes mellitus (p <0.007), previous antibiotic prophylaxis (p=0.017) or therapy (p<0.001), previous UTI (p=0.01), relapsing infection (p=0.019) and patients with delayed graft function after transplant (p=0.001) represented risk factors for infection by ESBL positive Enterobacteriaceae in KTPs. Interestingly, the period of time between data of transplantation and data of UTI was shorter in case of ESBL-P case-group (28.8 months) compared with ESBL-N control-group (50.9 months). ESBL-producing bacteria exhibited higher resistance to fluoroquinolones (p=0.002), trimethoprim-sulfamethoxazole (p<0.001) and gentamicin (p<0.001). Molecular analysis showed that blaCTX-M was the most common ESBL encoding gene (65.3%), although in 55.1% of the cases more than one ESBL gene was found. In 29.4% of K. pneumoniae isolates, three bla-genes (blaCTX-M-blaTEM-blaSHV) were simultaneously detected. Low estimated glomerular filtration rate (p=0.009) was found to be risk factor for UTI recurrence. Over 60% of recurrent UTI episodes were caused by genetically similar strains. UTI by ESBL-producing Enterobacteriaceae in KTPs represent an important clinical challenge regarding not only hospitalized patients but also concerning outpatients.

Cryptosporidium spp., Giardia lamblia y encephalitozoon intestinalis, oportunistas emergentes / Cryptosporidium spp., Giardia lamblia y encephalitozoon intestinalis emergent opportunists

Es un hecho conocido que las infecciones oportunistas por protozoos y hongos han aumentado en los últimos años, debido especialmente al aumento de las infecciones por VIH. Cryptosporidium spp., Giardia lamblia y Encephalitozoon intestinalis son protozoos y hongo, respectivamente, mundialmente reconocidos como agentes oportunistas emergentes, responsables de brotes epidémicos provocados por la ingestión de agua potable contaminada, incluso después de una correcta desinfección. La ingestión de estos protozoos puede provocar diferentes grados de enfermedad, entre aguda o leve (población sana) hasta situaciones más graves y agresivas, hasta a veces mortales (pacientes inmunocomprometidos y/o inmunodeprimidos). A pesar de ser responsables de muchos brotes epidémicos, su diagnóstico de laboratorio permanece arduo y trabajoso, incluso utilizando las nuevas técnicas desarrolladas en los últimos años. En esta revisión se resumen las consideraciones generales de estos oportunistas emergentes, así como los métodos de diagnóstico más usuales, incluso los más recientes y específicos.

Epidemiological data, regarding parasitic and fungi opportunist infections, have changed in the last years, especially due to HIV infection. Cryptosporidium spp., Giardia lamblia and Encephalitozoon intestinalis are protozoan and fungi, respectively, worldwide known as opportunistic emergent agents, being responsible by epidemic outbreaks after ingestion of contaminated water, even following a correct disinfection treatment. Its ingestion can cause different effects on individuals’ health, from light or acute among the healthy population, to serious, aggressive or even deadly among the immunodepressed or immunocompromised patients. Contaminated water ingestion can result in outbreaks but protozoa laboratory diagnosis still remains very laborious, even after the development of more sensitive and specific techniques in the last years. In this paper, a revision of these emergent opportunists, their main characteristics and diagnostic tools are described, including the most recent and specific techniques.

Extended-spectrum ß-lactamases of Escherichia coli and Klebsiella pneumoniae screened by the VITEK 2 system.

The VITEK 2 automated system (bioMérieux) is one of the most widely used instruments in clinical microbiology laboratories for the identification and evaluation of the susceptibility profiles of bacteria including the detection of extended-spectrum ß-lactamases (ESBLs) produced by Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca. Currently, the Clinical and Laboratory Standards Institute recommends the use of ESBL confirmatory tests in addition to standard susceptibility testing. In order to evaluate the accuracy of VITEK 2-positive results regarding clinical isolates of E. coli (n = 110) and K. pneumoniae (n = 72), four additional ESBL detection systems were compared: the Phoenix Automated Microbiology System (BD Diagnostic Systems) and the MicroScan WalkAway-96 System (Dade Behring), and two manual systems as confirmatory tests, the Etest (AB Biodisk) and double disc diffusion (DDS) test. Epidemiological data regarding the tested strains were also collected and their susceptibility phenotypes were determined. The four methods resulted in concordant results for 126 of the 182 strains. However, the different tests displayed distinct results: the VITEK 2 system was in disagreement in 23.9 % of cases with DDS, in 15.3 % with Etest, in 23 % with the MicroScan WalkAway-96 System and in 23.6 % with the Phoenix Automated Microbiology System. Epidemiological data indicated that the majority of ESBL-positive E. coli strains were isolated from patients admitted to internal medicine wards (72.7 %), whilst K. pneumoniae ESBL-positive isolates were equally distributed between internal medicine wards (45.8 %) and intensive care units (45.8 %). Most of these strains were isolated from urine. In contrast to ESBL-negative isolates, the ESBL-positive strains displayed multiple drug resistance, namely to quinolones, aminoglycosides and trimethoprim-sulfamethoxazole. No significant resistance to carbapenems was detected. Overall, this study demonstrates the need for a confirmatory test following positive ESBL detection with the VITEK 2 system (panel AST-037), which appears to yield a large number of false-positive results.

Preliminary results of the use an ultrasonic equipment in the treatment of moderate periodontitis: clinical and microbiological real time polimerase chain reacion-based (PCR) study

OBJETIVE: This preliminary study aimed to evaluate clinically and microbiologically the treatment of patients with light to moderate periodontal disease by using an ultrasonic device. MATERIAL AND METHODS: Sixteen adults with moderate periodontitis were studied. A Real-time PCR protocol was optimised using specific primers for the three microorganisms. Clinical and microbiological testing was performed prior and following treatment. RESULTS: Despite clinical improvement, bacteria quantification didn’t change. All the patients were positive for P. gingivalis and P. intermedia and nine for A. actinomycetemcomitans. CONCLUSION: VectorTM-system treatment showed clinical improvement. A Real-time PCR protocol is now available for periodontal diagnostics and monitorization. However, further studies with larger populations are indicated.

OBJETIVOS: Este estudo preliminar teve a finalidade de avaliar clinicamente microbiologicamente o tratamento de pacientes portadores de periodontite leve a moderada, utilizando-se um novo aparelho piezo-elétrico disponível no mercado (VectorTM system). MATERIAL E MÉTODO: Dezesseis pacientes adultos, portadores de periodontite leve a moderada, foram submetidos ao tratamento. Utilizou-se um protocolo de PCR em tempo real utilizando primers específicos para três microrganismos. Realizaram-se avaliação clínica e um estudo microbiológico simultâneo antes e após os tratamentos. RESULTADOS: A avaliação clínica foi positiva, embora não tendo ocorrido alterações na quantidade de bactérias. Todos os pacientes apresentaram amplificação específica para P. intermedia e P. gingivalis e nove pacientes para A. Actinomycetemcomitans. CONCLUSÃO: Considerando-se os resultados deste estudo preliminar, tratamento com o aparelho testado mostrou eficácia clínica. O protocolo utilizado neste estudo está agora disponível para diagnóstico periodontal e monitoração de resultados de tratamento. Entretanto, indica-se estudos clínicos e microbiológicos mais aprofundados, com amostras maiores, para conclusões mais consistentes.

In vitro evaluation of the antimicrobial activity of different antiseptics on contaminated gutta-percha cones / Estudo in vitro da atividade antimicrobiana de direferentes soluções antissépticas em cones de guta-percha contaminados

OBJECTIVES: The purpose of this in vitro study was to evaluate the effectiveness of different antisepticsfor decontamination of gutta-percha cones. MATERIALS AND METHODS: Thirty-six cones werecontaminated with standardized pure cultures of six different microorganisms: Staphylococcus aureus,Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Candida albicans. The cones were treated forfive minutes with different antiseptic solutions: 2% iodine alcohol, 3% sodium hypochlorite, 0.2%chlorohexidine and 5% citric acid. RESULTS: Iodine alcohol was the most effective for all themicroorganisms, except for Candida albicans. For this microorganism, the best results were obtainedwith 3% sodium hypochlorite and 5% citric acid; these two solutions showed moderate activity onother microorganisms. Chlorohexidine was not effective on any of the microorganisms.

OBJETIVOS: Neste trabalho avaliou-se a atividade antimicrobiana in vitro de diferentessoluções antissépticas na desinfecção de cones de guta-percha. MATERIAIS E MÉTODOS:Trinta e seis cones de guta-percha foram contaminados com culturas puras de diferentesmicrorganismos: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiellapneumoniae e Candida albicans. Os cones foram imersos em diferentes soluções antissépticas:álcool iodado a 2%, hipoclorito de sódio a 3%, clorhexidina a 0,2% e ácido cítrico a 5%,durante 5 minutos. RESULTADOS: Os resultados indicam que o álcool iodado é o maiseficaz sobre todos os microrganismos, exceto sobre a C. albicans. Sobre esta, o mais eficazfoi o hipoclorito de sódio a 3 %, mostrando moderada eficácia sobre os restantesmicrorganismos, tal como o ácido cítrico. A clorhexidina não mostrou eficácia sobre qualquerdos microrganismos, nestas condições experimentais.