Antimicrobial resistance in Streptococcus pneumoniae: mechanisms and current epidemiology

Infections caused by Streptococcus pneumoniae are a worrisome public health problem worldwide. Young children and elderly are the main age group affected and the highest burden of the disease are among developing countries. Pneumococcal infections cause 11% of the total of infant deaths, representing the leading cause of child death currently preventable by vaccination. Epidemiologic information about pneumococci in Brazil is somehow restrict, but available data reinforce the worrisome occurrence of pneumococcal diseases, which are commonly treated empirically. Limitations in the diagnostic methods, along with the severity of disease contribute to this behavior. Thus, surveillance studies are crucial to define the prevalence of resistant strains both globally or in a particular region, as these strains may compromise empirical therapeutical choices. However, although different clones of PNSP are internationally distributed, and considering diseases other than meningitis, the prevalence to penicillin is quite low, making this old, safe, and inexpensive drug an attractive first choice to treat pneumococcal infections. The widespread use of conjugate vaccines among children, influencing the circulation of resistant clones and the distribution of serotypes reinforces the need of surveillance studies to define prevalence of resistance.Infections caused by Streptococcus pneumoniae are a worrisome public health problem worldwide. Young children and the elderly are the main age groups affected and the highest burden of the disease is found in developing countries. Pneumococcal infections cause 11% of the total infant deaths, representing the leading cause of child death currently preventable by vaccination. Epidemiologic information about pneumococci in Brazil is somehow restricted, but available data reinforce the worrisome occurrence of pneumococcal diseases, which are commonly treated empirically. Limitations in the diagnostic methods, along with the severity of disease contribute to this behavior. Thus, surveillance studies are crucial to define the prevalence of resistant strains both globally and in a particular region, as these strains may compromise empirical therapeutic choices. However, although different clones of penicillin non-susceptible pneumococci are internationally distributed, and considering diseases other than meningitis, the prevalence of resistance to penicillin is quite low, making this old, safe, and inexpensive drug an attractive first choice to treat pneumococcal infections. The widespread use of conjugate vaccines among children, influencing the circulation of resistant clones and the distribution of serotypes reinforces the need of surveillance studies to define the prevalence of resistance

Indicações da evolução da resistência ao carbapenem através da heteroresistência como estágio intermediário no Acinetobacter baumannii após administração de carbapenem

We describe an in vivo evolution of an antimicrobial profile from susceptibility to full-resistance to carbapenems, with heteroresistance as an intermediate stage, in an Acinetobacter baumannii strain. Heteroresistance was characterized by the growth of sub-populations within the susceptibility halo in both disk-diffusion and Etest. PCRs for the main A. baumannii carbapenemases were negative. The exact resistance mechanism, diagnostic methods and clinical relevance of heteroresistance in A. baumannii warrant further investigations. This is the first description of such phenomenon in vivo and the second report of heteroresistance to carbapenems in A. baumannii.Descrevemos a evolução in vivo, de um perfil de sensibilidade aos antimicrobianos, passando de sensibilidade a resistência total aos antibióticos carbapenêmicos, com um estágio intermediário de heteroresistência em isolado de Acinetobacter baumannii. A heteroresistência foi caracterizada pelo crescimento de sub-população na zona de inibição pelo método de disco-difusão e pelo Etest. PCRs para as principais carbapenemases envolvidas com resistência neste microrganismo foram negativas. O exato mecanismo de resistência envolvido, método diagnóstico e relevância clínica justificam investigação adicional. Esta é a primeira descrição deste fenômeno in vivo e o segundo relato de heteroresistência em A. baumannii

Corynebacterium striatum infectando lesão cutânea maligna: a emergência de um patógeno oportunista

Descrevemos infecção de lesão neoplásica em paciente masculino de 27 anos, envolvendo pele e partes moles, causada por Corynebacterium striatum, um microrganismo raramente descrito como patógeno humano. A identificação foi confirmada por seqüenciamento de DNA. O paciente foi tratado com penicilina, com sucesso. O papel do C. striatum como patógeno oportunista é discutido.We described a case of a 27-year old male patient with skin and soft tissue infection of a neoplastic lesion caused by Corynebacterium striatum, an organism which has been rarely described as a human pathogen. Identification was confirmed by DNA sequencing. Successful treatment with penicillin was achieved. The role of the C. striatum as an emerging opportunistic pathogen is discussed

Molecular epidemiology of heteroresistant vancomycin-intermediate Staphylococcus aureus in Brazil

AbstractTo determine the epidemiological and molecular characteristics of 12 Staphylococcus aureus isolates presenting heteroresistance to vancomycin in laboratories of two cities in Santa Catarina, southern Brazil. Epidemiological data, including the city of isolation, health institution, and date of isolation were considered, as well as the associated clinical specimen. For molecular characterization, we analyzed the staphylococcal cassette chromosome types, the erm gene presence, and the genomic diversity of isolates using pulsed-field gel electrophoresis. The 12 isolates of S. aureus were previously confirmed as heteroresistance to vancomycin using the population analysis profile–area under curve. Regarding genetic variability, two clones were detected: the main one (clone A) composed of four isolates and the clones B, with two isolates. For clone A, two isolates presented identical band patterns and were related to the same hospital, with an interval of 57 days between their isolation. The other isolates of this clone showed no epidemiological link between them because they were isolated in different hospitals and had no temporal relationship. The other clone showed no detectable epidemiological relationship. The heteroresistance to vancomycin recovered in Santa Catarina State from 2009 to 2012 had, in general, heterogeneous genomic patterns based on pulsed-field gel electrophoresis results, which is in accordance with the fact that these isolates had little or no epidemiological relationship among them. Due to the characteristic phenotypic instability and often prolonged vancomycin therapy for selection, clonal spread is not as common as for other resistance mechanisms disseminated through horizontal gene transfer

Human papillomavirus knowledge, beliefs, and behaviors : a questionnaire adaptation

Objective: This study aims to adapt a questionnaire about the knowledge, beliefs and behaviors regarding HPV and related subjects into Brazilian Portuguese. Study Design: National Survey. Methods: The instrument was translated into Portuguese and retranslated into English separately. Experts assessed the validity of the content and cross-cultural adaptation of the instrument. The instrument was administered to 8580 male and female Brazilian adolescents and young adults (aged between 16 and 25 years) who participated in the National Survey of Human Papillomavirus Prevalence (POP-Brazil). This large-scale survey enrolled participants from 26 Brazilian capitals and the Federal District. Results: The full questionnaire is composed of 30 questions, with a good absolute agreement between its two halves (61.16 9.97). The preventive behavior section showed the lowest agreement. Men and women showed a difference concerning their knowledge about HPV (score for men 0.48 ( 8.93) vs. women 0.55 ( 4.51), p < 0.001). Conclusion: The proposed questionnaire is the first instrument able to describe the knowledge, beliefs and behaviors regarding HPV and related subjects in Brazilian women and men. This questionnaire appears to be adequate for use in future studies that may produce evidence and knowledge on these specific topics

Avaliação de métodos na detecção da MIC de vancomicina e mudanças na acurácia relacionada a diferentes valores de MIC

INTRODUÇÃO: Staphylococcus aureus resistente à meticilina (MRSA) apresentando suscetibilidade reduzida à vancomicina tem sido associado à falha terapêutica. Alguns métodos utilizados por laboratórios clínicos podem não ser suficientemente precisos para detectar este fenótipo, comprometendo os resultados e o desfecho do paciente. OBJETIVOS: Avaliar o desempenho de métodos na detecção dos valores de MIC de vancomicina entre isolados clínicos de MRSA. MATERIAIS E MÉTODOS: Determinamos a Concentração Inibitória Mínima de Vancomicina para 75 MRSA isolados de pacientes do Hospital Mãe de Deus, Porto Alegre, Brasil. Utilizamos a microdiluição em caldo como técnica padrão-ouro e os seguintes métodos: tiras de E-test® (BioMérieux), tiras M.I.C.E® (Oxoid), painel comercial da PROBAC® e sistema automatizado MicroScan® (Siemens). Além disso, foi realizado o teste de triagem em ágar com 3 µg/mL de vancomicina. RESULTADOS: Todos os isolados apresentaram MIC ≤ 2 µg/mL. Não houve diferença estatística entre os resultados do E-test® e da microdiluição em caldo. O painel da PROBAC® apresentou MICs, em geral, menores que o padrão-ouro (58,66% de erros maiores), enquanto que as MICs pelo M.I.C.E.® foram maiores (67,99% de erros menores). CONCLUSÕES: Para nossa população de MRSA, E-test® apresentou o melhor desempenho, embora com uma acurácia heterogênea, dependendo dos valores da MIC.INTRODUCTION: Methicillin-Resistant Staphylococcus aureus (MRSA) presenting reduced susceptibility to vancomycin has been associated to therapeutic failure. Some methods used by clinical laboratories may not be sufficiently accurate to detect this phenotype, compromising results and the outcome of the patient. OBJECTIVES: To evaluate the performance of methods in the detection of vancomycin MIC values among clinical isolates of MRSA. MATERIAL AND METHODS: The Vancomycin Minimal Inhibitory Concentration was determined for 75 MRSA isolates from inpatients of Mãe de Deus Hospital, Porto Alegre, Brazil. The broth microdilution (BM) was used as the gold-standard technique, as well as the following methods: E-test® strips (BioMérieux), M.I.C.E® strips (Oxoid), PROBAC® commercial panel and the automated system MicroScan® (Siemens). Besides, the agar screening test was carried out with 3 µg/mL of vancomycin. RESULTS: All isolates presented MIC ≤ 2 µg/mL for BM. E-test® had higher concordance (40%) in terms of global agreement with the gold standard, and there was not statistical difference among E-test® and broth microdilution results. PROBAC® panels presented MICs, in general, lower than the gold-standard panels (58.66% major errors), while M.I.C.E.® MICs were higher (67.99% minor errors). CONCLUSIONS: For the population of MRSA in question, E-test® presented the best performance, although with a heterogeneous accuracy, depending on MIC values

Susceptibility profiles and correlation with pneumococcal serotypes soon after implementation of the 10-valent pneumococcal conjugate vaccine in Brazil

SummaryObjectivesTo evaluate the susceptibility patterns among Streptococcus pneumoniae recovered during the years 2010–2012 and to correlate these with serotypes.MethodsPneumococci from invasive sites were serotyped by sequential multiplex PCR and/or Quellung reaction. Etest strips were used to determine the minimal inhibitory concentrations, and the Clinical and Laboratory Standards Institute (CLSI) guidelines were used for interpretation. Genetic determinants of macrolide resistance were assessed by PCR, and the occurrence of the D phenotype was analyzed following the recommendations of the CLSI.ResultsOne hundred fifty-nine S. pneumoniae were studied; most were recovered from blood and were associated with serotypes 14, 3, 4, 23F, 20, 7F, 12F, 19A, and 19F. Pneumococcal conjugate vaccine PCV7, PCV10, and PCV13 and 23-valent polysaccharide vaccine serotypes represented 38.2%, 48.7%, 64.5%, and 85.5%, respectively. β-Lactam non-susceptibility (non-meningitis) was basically related to serotype 19A. For meningitis, it was observed in 21.4% (serotypes 14, 3, 9V, 23F, and 24F). Resistance to erythromycin occurred in 8.2% and mefA was the most common macrolide genetic determinant. One isolate was resistant to levofloxacin. Non-susceptibility to trimethoprim–sulfamethoxazole was 37.7% and to tetracycline was 22.0%.ConclusionsOur population of pneumococci represents a transition era, soon after the introduction of PCV10. Non-susceptible patterns were found to be associated with classical PCV serotypes (especially serotype 14), which is still highly prevalent, and non-PCV10 ones (19A), which may disseminate, occupying the biological niche left by the vaccine serotypes