Resumo Introdução: Citomegalovírus (CMV) é uma importante causa de infecção viral após o transplante renal. Os métodos diagnósticos presentemente utilizados são a antigenemia pp-65 e os métodos que utilizam a amplificação de ácidos nucléicos pela reação em cadeia da polimerase (PCR) e visam à detecção da replicação viral. Objetivo: O objetivo deste estudo foi avaliar e comparar a incidência de infecção ativa por CMV em pacientes transplantados renais pelos dois métodos e estabelecer a melhor correlação clínico-laboratorial. Métodos: Trinta pacientes transplantados renais seqüenciais em um único centro foram incluídos em um estudo de coorte prospectiva. Amostras de sangue periférico foram coletadas a partir do 15º dia até o 6º mês pós-transplante e avaliadas para replicação de CMV por Antigenemia pp-65 e PCR quantitativo (qPCR). Resultados: Foram analisadas 240 amostras e a incidência de infecção ativa foi similar pelos dois métodos. O tempo médio transcorrido desde o transplante até o primeiro teste com resultado positivo foi quase idêntico entretanto mais amostras tiveram resultado positivo por qPCR do que antigenemia, um comportamento que se manteve quase uniforme ao longo do tempo. Concordância entre os testes foi observada em 217 amostras (90,4%; kappa = 0,529; p < 0,001) e em 25 pacientes (83,3%; kappa = 0,667; p < 0,001). A avaliação dos parâmetros diagnósticos para replicação de CMV revelaram maior sensibilidade para qPCR (82,1%) contra antigenemia (59,0%). PCR quantitativo também foi levemente mais preciso do que antigenemia. Conclusão: Nossos dados demonstram que ambos os métodos são adequados e tem precisão quase equivalente para a detecção da replicação do CMV após o transplante renal. A escolha entre um ou outro deve levar em consideração a demanda, capacidade de execução e custo-efetividade em cada instituição.

Abstract Introduction: Cytomegalovirus (CMV) infection is a main viral infection after kidney transplantation. The diagnostic methods currently employed are pp65 antigenemia and nucleic acid amplification by polymerase chain reaction (PCR) and aim at detecting viral replication. Objective: The goal of this study was to evaluate and compare by both methods the incidence of CMV active infection in kidney transplant patients and to establishthe best clinical-laboratory correlation. Methods: Thirty sequential kidney transplant recipients were enrolled in a single center prospective cohort study. Peripheral blood samples were drawn from day 15 until the 6th month after transplantation and tested for CMV replication by pp65 antigenemia and quantitative PCR assays (qPCR). Results: Two hundred forty samples were analyzed and the incidence of active infection was similar by both methods. Time elapsed to the first positive test was almost identical but more samples tested positive by qPCR than by antigenemia in a behavior that was almost evenly distributed overtime. Agreement between tests was observed in 217 samples (90.4%; kappa = 0.529; p < 0.001) and in 25 patients the tests were concordant (83.3%; kappa = 0.667; p < 0.001). The evaluation of the diagnostic parameters for CMV replication revealed higher sensitivity for the qPCR test (82.1%) against antigenemia (59.0%). Quantitative PCR was also slightly more accurate than antigenemia. Conclusion: Our data demonstrate that both methods are suitable and have almost equivalent accuracy for the detection of post-transplant cytomegalovirus replication. The choice for either test must take in consideration the demand, execution capability and cost-effectiveness at each institution.

Burkholderia cenocepacia may cause serious infections in patients with cystic fibrosis, and this microorganism can be highly transmissible. Pulsed-field gel electrophoresis is widely used to study the dynamics of strain spread in cystic fibrosis patients. The aim of this work was to perform pulsed-field gel electrophoresis-based molecular typing of B. cenocepacia isolates to evaluate the epidemiology of this species at our hospital. A total of 28 isolates from 23 cystic fibrosis patients were analyzed. Initially, we compared isolates obtained from the same patient at different periods of time. We then compared the pulsed-field gel electrophoresis profiles of 15 IIIA isolates, and in a third analysis, evaluated the genetic profile of 8 IIIB isolates from different patients. The pulsed-field gel electrophoresis profiles of isolates from the same patient indicated that they are genetically indistinguishable. Analysis of isolates from different patients revealed the presence of multiple clonal groups. These results do not indicate cross-transmission of a unique clone of B. cenocepacia among cystic fibrosis patients, although this has been observed in some patients. Our findings highlight the importance of adequate patient follow-up at cystic fibrosis centers and adherence to management and segregation measures in cystic fibrosis patients colonized with B. cenocepacia.

Streptococcus agalactiae or group B Streptococcus (GBS) is one of the most important causal agents of serious neonatal infections. Numerous assays have been evaluated for GBS screening in order to validate a fast and efficient method. The aim of this study was to compare the culture technique (established as the gold standard) with the molecular method of polymerase chain reaction (PCR) with specific primers (atr gene). Two hundred and sixty-three samples were analyzed. Vaginal samples were collected, according to the Centers for Disease Control and Prevention (CDC) recommendations, from women over 35 weeks of pregnancy at Hospital de Clínicas de Porto Alegre (HCPA). Two different extraction methods were tested in all samples collected. PCR technique yielded 71 (26.99%) positive results. Sensitivity and specificity for PCR were 100% and 86.88%, respectively. PCR demonstrated a shorter turnaround time than the culture. The molecular methodology proved to be a useful screening for GBS, allowing effective treatment to be initiated in shorter time to prevent newborn infection.

INTRODUÇÃO: O citomegalovírus humano (HCMV), causador de infecção latente, reativa com frequência em pacientes imunossuprimidos. Portanto, o HCMV permanece uma das infecções mais comuns após transplantes de órgãos sólidos e de células hematopoiéticas resultando em significativa morbidade, perda do enxerto e ocasional mortalidade. Assim, o diagnóstico precoce para uma terapia preventiva é de grande importância. Este estudo visa comparar o desempenho dos métodos PCR qualitativo in-house e antigenemia pp65 para o diagnóstico de infecção por CMV em pacientes imunossuprimidos do Hospital de Clínicas de Porto Alegre. MÉTODOS: O estudo foi realizado em 216 amostras de sangue total (EDTA) coletadas de 85 pacientes, entre agosto de 2006 e janeiro de 2007. RESULTADOS: Dentre as 216 amostras analisadas, 81 (37,5%) amostras apresentaram resultados positivos na PCR, enquanto 48 (22,2%) apresentaram resultados positivos na antigenemia. A sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo para a PCR, considerando antigenemia como padrão foram 87,5%, 76,8%, 51,8% e 95,5%, respectivamente. CONCLUSÕES: Estes resultados demonstraram que a PCR tem alta sensibilidade e valor preditivo negativo. Consequentemente PCR é especialmente indicada para o diagnóstico inicial de infecção por HCMV. No caso da estratégia de terapia preventiva, a identificação de pacientes com alto risco para a doença por HCMV é fundamental e a PCR pode ser uma ferramenta útil.

INTRODUCTION: Human cytomegalovirus (HCMV) is often reactive in latently infected immunosuppressed patients. Accordingly, HCMV remains one of the most common infections following solid organ and hemopoietic stem cell transplantations, resulting in significant morbidity, graft loss and occasional mortality. The early diagnosis of HCMV disease is important in immunosuppressed patients, since in these individuals, preemptive treatment is useful. The objective of this study was to compare the performance of the in-house qualitative polymerase chain reaction (PCR) and pp65 antigenemia to HCMV infection in immunosuppressed patients in the Hospital de Clínicas of Porto Alegre (HCPA). METHODS: A total of 216 blood samples collected between August 2006 and January 2007 were investigated. RESULTS: Among the samples analyzed, 81 (37.5%) were HCMV-positive by PCR, while 48 (22.2%) were positive for antigenemia. Considering antigenemia as the gold standard, sensitivity, specificity, positive predictive values and negative predictive values for PCR were 87.5%, 76.8%, 51.8% and 95.5% respectively. CONCLUSIONS: These results demonstrated that qualitative PCR has high sensitivity and negative predictive value (NPV). Consequently PCR is especially indicated for the initial diagnosis of HCMV infection. In the case of preemptive treatment strategy, identification of patients at high-risk for HCMV disease is fundamental and PCR can be useful tool.

INTRODUCTION: Resistance to macrolides, lincosamides and streptogramins B (MLS B antibiotics) in staphylococci may be due to modification in ribosomal target methylase encoded by erm genes. The expression of MLS B resistance lead to three phenotypes, namely constitutive resistance (cMLS B), inducible resistance (iMLS B), and resistance only to macrolides and streptogramins B (MS B). The iMLS B resistance is the most difficult to detect in the clinical laboratory. OBJECTIVE: This study investigated the expression of MLS B resistance and the prevalence of the erm genes among 152 clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococcus (CNS) from Hospital de Clínicas de Porto Alegre. METHODS: Primary MLS B resistance was detected by the disk diffusion method. Isolates with iMLS B phenotype were tested by double-disk induction method. All isolates were tested by a genotypic assay, PCR with specific primers. RESULTS: A total of 46.7% of staphylococci were positive for cMLS B; 3.3% for iMLS B and 3.3% for MS B. One or more erm genes were present in 50.1% of isolates. The gene ermA was detected in 49 isolates, ermC in 29 and ermB in 3. CONCLUSION: The prevalence of the ermA, ermB and ermC genes were 29.6%, 17.1% and 0.66% respectively, and constitutive resistance was the most frequent as compared to the other two phenotypes.

INTRODUÇÃO: Colonização pulmonar bacteriana é a principal causa de morbidade em fibrose cística (FC). Patógenos como Staphylococcus aureus são muito bem adaptados ao ambiente pulmonar e podem persistir por anos no mesmo paciente. Determinantes genéticos desta bactéria, como presença de SCCmec emergiram recentemente como um problema nesta população de pacientes. MÉTODOS: Foram comparados isolados de Staphylococcus aureus obtidos de diferentes materiais clínicos, de pacientes com e sem FC atendidos em um hospital de referência em tratamento de fibrocísticos de acordo com o tipo de SCCmec e o perfil de susceptibilidade aos antimicrobianos. RESULTADOS: Foram coletados 364 Staphylococcus aureus, um isolado por paciente, sendo 164 (45%) de pacientes com FC. Entre estes pacientes, 57/164 (44,5%) eram MRSA, e entre pacientes não fibrocísticos, MRSA compreendiam 89/200 (35%). Foram encontrados outros patógenos, associados ao Staphylococcus aureus, em 38 pacientes com FC. Todos 57 MRSA de pacientes com FC possuíam o cassete de multiresistência tipo III. Por outro lado, 31/89 MRSA de pacientes não fibrocísticos possuíam SCCmec tipo I (35%) e 44/89 possuíam tipo III (49%). O perfil de susceptibilidade aos antimicrobianos foi similar entre pacientes com e sem FC. CONCLUSÕES: A alta prevalência do SCCmec de multiresistência tipo III entre pacientes com FC comparado com pacientes sem FC em nossa instituição pode dificultar o controle da progressão da doença, feito através da antibioticoterapia, e que promove a sobrevivência deste tipo de paciente.

INTRODUCTION: Bacterial colonization of the lungs is the main cause of morbidity in cystic fibrosis (CF). Pathogens such as Staphylococcus aureus are very well adapted to the pulmonary environment and may persist for years in the same patient. Genetic determinants of these bacteria, such as the presence of SCCmec have recently emerged as a problem in this population of patients. METHODS: Staphylococcus aureus isolates obtained from different clinical materials coming from CF and non-CF patients attended at a cystic fibrosis reference hospital were compared according to SCCmec type and antibiotic susceptibility profile. RESULTS: Three hundred and sixty-four single-patient Staphylococcus aureus isolates were collected, of which 164 (45%) were from CF patients. Among the latter, 57/164 (44.5%) were MRSA, and among the non-CF patients, 89/200 (35%) were MRSA. Associated pathogens were found in 38 CF patients. All 57 MRSA from CF patients harbored the multiresistant cassette type III. In contrast, 31/89 MRSA from non-CF patients harbored SCCmec type I (35%) and 44/89 harbored type III (49%). The antibiotic susceptibility pattern was similar between CF and non-CF patients. CONCLUSIONS: The high prevalence of multiresistant SCCmec type III among CF patients compared with non-CF patients in our institution may make it difficult to control disease progression through antibiotic therapy for promoting the survival of this kind of patient.

Meningitis is a severe and potentially fatal form of tuberculosis. The diagnostic workup involves detection of acid-fast bacilli (AFB) in the cerebrospinal fluid (CSF) by microscopy or culture, however, the difficulty in detecting the organism poses a challenge to diagnosis. The use of the polymerase chain reaction (PCR) in the diagnostic approach to Mycobacterium tuberculosis (MTB) meningitis has been reported as a fast and accurate method, with several commercial kits available. As an alternative, some institutions have been developing inexpensive in house assays. In our institution, we use an in house PCR for tuberculosis. We analyzed the performance of our PCR for the diagnosis of MTB meningitis in 148 consecutive patients, using MTB culture as gold standard. The sensitivity and specificity of CSF PCR for the diagnosis of MTB meningitis was 50% and 98.6% respectively with a concordance with CSF mycobacterial culture of 96% (Kappa=0.52). In contrast to CSF cultures for MTB, our PCR test is a fast, simple and inexpensive tool to diagnose tuberculous meningitis with a performance similar to that obtained with the available commercial kits.

OBJETIVO: Determinar a prevalência da infecção congênita por citomegalovírus em recém-nascidos internados na unidade de terapia intensiva neonatal de um hospital público de Porto Alegre. METODOS: Estudo transversal, incluindo 261 recém-nascidos que nasceram em um hospital público da cidade de Porto Alegre no ano de 2003 e foram internados na unidade de terapia intensiva neonatal. Foi coletada amostra de urina nos primeiros 7 dias de vida e realizado o teste de reação em cadeia da polimerase para a pesquisa do DNA do citomegalovírus. RESULTADOS: A prevalência de infecção congênita por citomegalovírus na população estudada foi de 0,8% (IC 95%: 0,097-2,86). Devido à baixa prevalência, não foi possível associar fatores de risco. CONCLUSÕES: A prevalência de infecção congênita por citomegalovírus em uma unidade de terapia intensiva neonatal de um hospital público de Porto Alegre não foi considerada elevada, sendo semelhante à prevalência encontrada em outros estudos realizados.

OBJECTIVE: To determine the prevalence of congenital cytomegalovirus infection in newborn infants admitted to an intensive care unit in a public hospital in Porto Alegre. METHODS: A cross-sectional study of 261 newborn infants born at a public hospital in the city of Porto Alegre in 2003 and admitted to the intensive care ward. Urine samples were collected within 7 days of birth and a polymerase chain reaction-PCR performed to test for cytomegalovirus DNA. RESULTS: The prevalence of congenital cytomegalovirus infection among the study population was 0.8% (95% CI: 0.097%-2.86%). It was not possible to assess risk factors because this prevalence was so low. CONCLUSIONS: The prevalence of congenital cytomegalovirus infection in an intensive care unit at a public hospital in Porto Alegre was not considered elevated and was comparable with prevalence rates found by other studies.