Tendências em medicina laboratorial / Trends in laboratory medicine

A patologia clínica/medicina laboratorial é uma especialidade direcionada à realização de exames complementares no auxílio ao diagnóstico, com impacto nos diferentes estágios da cadeia de saúde: prevenção, diagnóstico, prognóstico e acompanhamento terapêutico. Diversos elementos apontam para maior utilização da medicina diagnóstica no futuro. Para discutirmos as principais tendências na medicina laboratorial, descrevemos os fatores que colaboram e são fundamentais para o crescimento desse mercado denominados, neste estudo, drivers de crescimento. As principais tendências que terão forte impacto na medicina laboratorial, e que serão descritas neste artigo, são: ferramentas de gestão, inserção de novos testes no mercado e rol de procedimentos, qualidade dos serviços em medicina diagnóstica, modelos de operação, automação, consolidação e integração, tecnologia da informação, medicina personalizada e genética. Sabemos que a medicina diagnóstica demonstra sua importância ao participar de 70 por cento das decisões clínicas, absorvendo uma pequena parte dos custos em saúde (cerca de 10 por cento). Todas as tendências analisadas neste trabalho apontam para um crescimento na utilização dos exames laboratoriais e também para sua importância na cadeia de saúde. Esse novo posicionamento, somado às novas expectativas de alta resolubilidade, pressiona o mercado e as companhias que o compõem a buscar mudanças e novas estratégias de atuação.

Clinical pathology/laboratory medicine, a specialty focused on performing complementary tests to aid diagnosis, has impact upon several stages of health care: prevention, diagnosis, prognosis, and therapeutic management. There are several factors that will foster the use of laboratory medicine in the future. In order to discuss the main trends in laboratory medicine, this article describes the major factors that have promoted growth in this market, which herein are referred to as growth drivers. The major trends that will cause substantial impact on laboratory medicine are: management tools, inclusion of new tests and procedures, service quality, operational models, automation, consolidation and integration, information technology, personalized and genetic medicine. Laboratory medicine occupies a pivotal role in 70 percent of all clinical decisions with minimal healthcare costs of approximately 10 percent. All trends discussed herein sustain an increase in the use of laboratory tests as well as its importance in health care. Both this new model and the expectation of optimal solutions have led the market to search for changes and new management strategies.

Conceitos de automação na medicina laboratorial: revisão de literatura / Concepts in laboratory medicine automation: literature review

Nas últimas décadas, a introdução da automação na medicina laboratorial foi destacada como a espinha dorsal na busca de eficiência e viabilidade das empresas atuantes nesse setor e expandiu-se em todas as fases dos processos no laboratório clínico: pré-analítica, analítica e pós-analítica. A implementação de um processo de automação laboratorial deve levar em consideração o posicionamento estratégico da empresa e sua forma de atuação. Diferentes modelos de processos automatizados funcionam para diferentes negócios, definidos pelo mix de exames, volume de processamento, atributos estratégicos necessários, capacidade de investimento, entre outros. Este artigo tem como principal objetivo apresentar uma breve revisão dos processos automatizados disponíveis em medicina laboratorial.

In the last decades, the introduction of automation in laboratory medicine has played a major role in the search for efficiency and viability promoted by enterprises from this sector. Additionally, it has been expanded to all phases and processes within clinical laboratories: pre-analytical, analytical and post-analytical. Automation program implementation must take into account the company's strategic planning and business approach. Different automated processes cater for different business platforms, which are defined by test mix, workflow volume, required strategic characteristics, investment capacity, among others. This article aims at briefly reviewing the automation processes available in laboratory medicine.

A pharmacodynamic strategy to optimize empirical antibiotic therapy for gram-negative bacteria in a Brazilian Intensive Care Unit.

Pharmacodynamic analyses were proposed to determine optimal empirical antibiotic therapy against Gram-negative bacteria isolated in a Brazilian ICU. Due to high resistance rates, standard regimens of cefepime, ciprofloxacin, meropenem, and piperacillin/tazobactam were not able to attain significant bactericidal CFR. Prolonged infusion of meropenem achieved 88% CFR, making it a possible empirical regimen in this ICU until susceptibilities become available. Still, even through administration of high dose prolonged infusions, 12.0% of simulated subjects did not achieve bactericidal exposure, suggesting that combination therapy would frequently be required in this setting. In conclusion, we recommend that in the presence of identified resistance problems among Gram-negative bacteria in a unit or hospital, MIC testing of formulary agents should be conducted along with pharmacodynamic simulation to assist in choosing an optimal antibiotic and dosage regimen for empirical use of severe infections until cultures and susceptibilities become available.

A pharmacodynamic strategy to optimize empirical antibiotic therapy for gram-negative bacteria in a Brazilian Intensive Care Unit

Pharmacodynamic analyses were proposed to determine optimal empirical antibiotic therapy against Gram-negative bacteria isolated in a Brazilian ICU. Due to high resistance rates, standard regimens of cefepime, ciprofloxacin, meropenem, and piperacillin/tazobactam were not able to attain significant bactericidal CFR. Prolonged infusion of meropenem achieved 88 percent CFR, making it a possible empirical regimen in this ICU until susceptibilities become available. Still, even through administration of high dose prolonged infusions, 12.0 percent of simulated subjects did not achieve bactericidal exposure, suggesting that combination therapy would frequently be required in this setting. In conclusion, we recommend that in the presence of identified resistance problems among Gram-negative bacteria in a unit or hospital, MIC testing of formulary agents should be conducted along with pharmacodynamic simulation to assist in choosing an optimal antibiotic and dosage regimen for empirical use of severe infections until cultures and susceptibilities become available.

Antibiotic resistance and trend of urinary pathogens in general outpatients from a major urban city.

OBJECTIVE: We assessed the antimicrobial resistance patterns of pathogens responsible for urinary tract infections (UTI) in outpatients in São Paulo, Brazil, as well as the Escherichia coli antimicrobial resistance trend. MATERIALS AND METHODS: Outpatients urine cultures were collected from January 2000 to December 2003. Statistical analysis considered positive results for one bacterial species with colony count >or= 100,000 CFU/mL. Stratification was done on age group and gender. Statistical tests used included chi-square and the chi-square test for trend to evaluate differences between susceptibility rates among age groups and ordering in the E. coli resistance rates per year, respectively. RESULTS: There were 37,261 positive results with Enterobacteriaceae isolated in 32,530 (87.3%) and Gram-positive cocci in 2,570 (6.9%) cultures. E. coli had the highest prevalence (71.6%). Susceptibility tests were performed in 31,716 cultures. E. coli had elevated resistance rates (> 30%) to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline. Significant differences between age groups and ordering among years were observed. CONCLUSIONS: The use of trimethoprim-sulfamethoxazole is precluded in the population studied due to elevated resistance rates (> 30%) among most prevalent pathogens. Significant resistance rate differences among age groups and years were observed, particularly for fluoroquinolones. Fluoroquinolones should be used with caution. Nitrofurantoin should be used as empirical therapy for primary, non-complicated urinary tract infections.

Antibiotic resistance and trend of urinary pathogens in general outpatients from a major urban city

OBJECTIVE: We assessed the antimicrobial resistance patterns of pathogens responsible for urinary tract infections (UTI) in outpatients in São Paulo, Brazil, as well as the Escherichia coli antimicrobial resistance trend. MATERIALS AND METHODS: Outpatients urine cultures were collected from January 2000 to December 2003. Statistical analysis considered positive results for one bacterial species with colony count > 100,000 CFU/mL. Stratification was done on age group and gender. Statistical tests used included chi-square and the chi-square test for trend to evaluate differences between susceptibility rates among age groups and ordering in the E. coli resistance rates per year, respectively. RESULTS: There were 37,261 positive results with Enterobacteriaceae isolated in 32,530 (87.3 percent) and Gram-positive cocci in 2,570 (6.9 percent) cultures. E. coli had the highest prevalence (71.6 percent). Susceptibility tests were performed in 31,716 cultures. E. coli had elevated resistance rates (> 30 percent) to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline. Significant differences between age groups and ordering among years were observed. CONCLUSIONS: The use of trimethoprim-sulfamethoxazole is precluded in the population studied due to elevated resistance rates (> 30 percent) among most prevalent pathogens. Significant resistance rate differences among age groups and years were observed, particularly for fluoroquinolones. Fluoroquinolones should be used with caution. Nitrofurantoin should be used as empirical therapy for primary, non-complicated urinary tract infections.

Antimicrobial susceptibility of Gram-negative bacteria in Brazilian hospitals: the MYSTIC Program Brazil 2003.

Establish the susceptibility pattern of Gram-negative bacteria causing infections in ICU patients, MYSTIC Program Brazil 2003. Gram-negative bacteria (n = 1,550) causing nosocomial infections were collected at 20 Brazilian centers. The central laboratory confirmed the identification and performed the susceptibility tests by Etest methodology (AB Biodisk, Solna, Sweden) for meropenem, imipenem, ciprofloxacin, ceftazidime, cefepime, cefotaxime, piperacillin/tazobactam, gentamicin, and tobramycin. Interpretation criteria used were according to National Committee for Clinical Laboratory Standards (NCCLS). Pseudomonas aeruginosa (30.3%) was the most frequent isolate, followed by E. coli (18.6%), Klebsiella pneumoniae (16.9%), Acitenobacter baumannii (8.8%), and Enterobacter cloacae (7.1%). Pseudomonas aeruginosa (n=470) isolates presented susceptibility rates of 64% to meropenem, 63.8% to piperacillin/tazobactam, 63.4% to amikacin, 58.7% to imipenem. Acitenobacter baumannii presented susceptibility rates to meropenem of 97.1%, and 73% to tobramycin. E. coli and K. pneumoniae were highly susceptible to both carbapenems. Carbapenem resistance among the Enterobacteriaceae is still rare in the region. Acitenobacter baumannii and P. aeruginosa presented elevated resistance rates to all antimicrobials. Since they play an important role in nosocomial infections in this environment, the use of empirical combination therapy to treat these pathogens may be justified.

Pseudomonas aeruginosa clonal dissemination in Brazilian intensive care units.

OBJECTIVE: Investigate clonal dissemination of nosocomial multidrug-resistant Pseudomonas aeruginosa isolates within and between Brazilian intensive care units, which participated in the MYSTIC Program Brazil 2002. METHODS: Thirty-six P. aeruginosa isolates resistant to meropenem or imipenem plus at least two of the following drugs: ciprofloxacin, cefepime, ceftazidime or piperacillin/tazobactam were isolated during 2002 at 4 centres in São Paulo and 1 centre in Brasília. Chromosomal restriction fragments obtained with SpeI were separated by pulsed-field gel electrophoresis (PFGE). Electrophoretic patterns were analyzed with GelCompar II v. 2.5. RESULTS: Five major clones were identified (A, B, C, D, G). Clone A was constituted by 8 isolates with indistinguishable PFGE pattern present in 2 centres. Clone B was constituted by 4 indistinguishable isolates predominant in centre 6. Clone C had 3 indistinguishable isolates, with closely related clones (C1-3). Also, Clone D had 3 indistinguishable isolates, with closely related (D1) and possibly related (D2/D3) clones. Clones C and D were present in centre 1. Clone G was constituted by 2 indistinguishable isolates and was present in centre 7. Finally, 8 isolates were unique. Isolates from Centre 4 were unique. CONCLUSIONS: Clonal dissemination was detected within (clones A, B, C, D, and G) and between centres (clone A). These findings are important when analyzing surveillance data, since susceptibility rates may be significantly affected by the dissemination of a resistant clone.

Diseminación clonal de Pseudomonas aeruginosa en unidades de cuidados intensivos brasileñas / Pseudomonas aeruginosa clonal dissemination in Brazilian intensive care units

Objetivo. Investigar la diseminación clonal de cepas nosocomiales multirresistentes de Pseudomonas aeruginosa en y entre unidades de cuidados intensivos brasileñas participantes en el MYSTIC Program Brazil 2002.Métodos. Durante 2002, se aislaron en cuatro hospitales de São Paulo y en un hospital de Brasilia 36 cepas de P. aeruginosa resistentes a meropenem o imipenem y a al menos dos de los siguientes: ciprofloxacino, cefepima, ceftazidima o piperacilina/tazobactam. Los fragmentos de restricción cromosómica obtenidos mediante Spel se separaron con electroforesis en campo pulsado (PFGE) y se analizaron mediante GelCompar II v.2.5. Resultados. Se identificaron cinco clones principales (A, B, C, D y G). El clon A constaba de ocho cepas con un patrón PFGE indistinguible, aisladas en dos centros. El clon B estaba formado por cuatro cepas indistinguibles, predominantes en el centro 6. El clon C estaba formado por tres cepas indistinguibles con clones estrechamente relacionados (C1-3). Además, el clon D estaba formado por tres cepas indistinguibles con clones estrechamente (D1) o posiblemente relacionados (D2/D3). Los clones C y D se detectaron en el centro 1. El clon G estaba formado por dos cepas indistinguibles y se observó en el centro 7. Finalmente, ocho cepas fueron específicas. Las cepas del centro 4 fueron específicas. Conclusiones. Se detectó diseminación clonal en los propios centros (clones A, B, C, D y G) y entre centros (clon A). Estos hallazgos son importantes para evaluar los datos de vigilancia epidemiológica pues la diseminación de un clon resistente puede influir de manera significativa en las tasas de sensibilidad (AU)

Objective. Investigate clonal dissemination of nosocomial multidrug-resistant Pseudomonas aeruginosa isolates within and between Brazilian intensive care units, which participated in the MYSTIC Program Brazil 2002. Methods. Thirty-six P. aeruginosa isolates resistant to meropenem or imipenem plus at least two of the following drugs: ciprofloxacin, cefepime, ceftazidime or piperacillin/tazobactam were isolated during 2002 at 4 centres in São Paulo and 1 centre in Brasília. Chromosomal restriction fragments obtained with SpeI were separated by pulsed-field gel electrophoresis (PFGE). Electrophoretic patterns were analyzed with GelCompar II v. 2.5.Results. Five major clones were identified (A, B, C, D, G). Clone A was constituted by 8 isolates with indistinguishable PFGE pattern present in 2 centres. Clone B was constituted by 4 indistinguishable isolates predominant in centre 6. Clone C had 3 indistinguishable isolates, with closely related clones (C1-3). Also, Clone D had 3 indistinguishable isolates, with closely related (D1) and possibly related (D2/D3) clones. Clones C and D were present in centre 1. Clone G was constituted by 2 indistinguishable isolates and was present in centre 7. Finally, 8 isolates were unique. Isolates from Centre 4 were unique. Conclusions. Clonal dissemination was detected within (clones A, B, C, D, and G) and between centres (clone A). These findings are important when analyzing surveillance data, since susceptibility rates may be significantly affected by the dissemination of a resistant clone (AU)

In vitro synergy test of meropenem and sulbactam against clinical isolates of Acinetobacter baumannii.

Meropenem and imipenem are often the drugs of choice for the treatment of infections due to multidrug-resistant Acinetobacter baumannii. The present study aimed at evaluating the interaction between meropenem and sulbactam through microdilution and checkerboard methods against 48 clinical isolates of A. baumannii collected from Brazilian hospitals. All the isolates presented elevated minimum inhibitory concentration (>or=2 microg/mL) to either meropenem or sulbactam. The checkerboard method with the combination of meropenem and sulbactam demonstrated 29.2% (14/48) synergism, 47.9% (23/48) partial synergism, 10.5% (5/48) additive, 6.2% (3/48) indifference, and 6.2% (3/48) antagonism (SigmaFIC(min)=0.09 and SigmaFIC(max)=8). Thus, combinations of meropenem and sulbactam may show synergism or partial synergism for most A. baumannii isolates. Further studies may help identify treatment options for patients with infections caused by these organisms, particularly with this combination, where both drugs have time-dependent activities and might be suitable for therapy optimization studies.

Antimicrobial susceptibility in intensive care units: MYSTIC Program Brazil 2002.

OBJECTIVE: Establish the susceptibility pattern of Gram-negative bacteria causing infections in ICU patients, MYSTIC Program Brazil 2002. MATERIAL AND METHODS: Gram-negative bacteria (n = 503) causing nosocomial infections were collected at seven Brazilian centers. The central laboratory confirmed the identification and performed the susceptibility tests by E-test methodology (AB Biodisk, Solna, Sweden) for meropenem, imipenem, ciprofloxacin, ceftazidime, cefepime, cefotaxime, piperacillin/tazobactam, gentamicin, and tobramycin. Interpretation criteria used were according to National Committee for Clinical Laboratory Standards (NCCLS). RESULTS: Pseudomonas aeruginosa (33%) was the most frequently isolated, followed by A. baumannii (17.1%), K. pneumoniae (12.1%), E. coli (10.5%), and E. cloacae (7.9%). Pseudomonas aeruginosa isolates had susceptibility rates of 67.5% to piperacillin/tazobactam, 59.8% to meropenem, 57.3% to imipenem. A. baumannii presented susceptibility rates to meropenem of 89.5%, 88.4% to imipenem, and 74.4% to tobramycin. E. coli and K. pneumoniae were fully susceptible to both carbapenems. CONCLUSIONS: Carbapenem resistance among Enterobacteriaceae is still rare in this region. A. baumannii and P. aeruginosa presented elevated resistance rates to all antimicrobials. Since these two bacterial species play an important role in nosocomial infections, the use of empirical combination therapy to treat these pathogens may be justified.

Antimicrobial susceptibility of Gram-negative bacteria in Brazilian hospitals: the MYSTIC Program Brazil 2003

Establish the susceptibility pattern of Gram-negative bacteria causing infections in ICU patients, MYSTIC Program Brazil 2003. Gram-negative bacteria (n = 1,550) causing nosocomial infections were collected at 20 Brazilian centers. The central laboratory confirmed the identification and performed the susceptibility tests by Etest methodology (AB Biodisk, Solna, Sweden) for meropenem, imipenem, ciprofloxacin, ceftazidime, cefepime, cefotaxime, piperacillin/tazobactam, gentamicin, and tobramycin. Interpretation criteria used were according to National Committee for Clinical Laboratory Standards (NCCLS). Pseudomonas aeruginosa (30.3 percent) was the most frequent isolate, followed by E. coli (18.6 percent), Klebsiella pneumoniae (16.9 percent), Acitenobacter baumannii (8.8 percent), and Enterobacter cloacae (7.1 percent). Pseudomonas aeruginosa (n=470) isolates presented susceptibility rates of 64 percent to meropenem, 63.8 percent to piperacillin/tazobactam, 63.4 percent to amikacin, 58.7 percent to imipenem. Acitenobacter baumannii presented susceptibility rates to meropenem of 97.1 percent, and 73 percent to tobramycin. E. coli and K. pneumoniae were highly susceptible to both carbapenems.Carbapenem resistance among the Enterobacteriaceae is still rare in the region. Acitenobacter baumannii and P. aeruginosa presented elevated resistance rates to all antimicrobials. Since they play an important role in nosocomial infections in this environment, the use of empirical combination therapy to treat these pathogens may be justified.

Antimicrobial susceptibility in intensive care units: MYSTIC Program Brazil 2002

OBJECTIVE: Establish the susceptibility pattern of Gram-negative bacteria causing infections in ICU patients, MYSTIC Program Brazil 2002. MATERIAL AND METHODS: Gram-negative bacteria (n = 503) causing nosocomial infections were collected at seven Brazilian centers. The central laboratory confirmed the identification and performed the susceptibility tests by E-test methodology (AB Biodisk, Solna, Sweden) for meropenem, imipenem, ciprofloxacin, ceftazidime, cefepime, cefotaxime, piperacillin/tazobactam, gentamicin, and tobramycin. Interpretation criteria used were according to National Committee for Clinical Laboratory Standards (NCCLS). RESULTS: Pseudomonas aeruginosa (33 percent) was the most frequently isolated, followed by A. baumannii (17.1 percent), K. pneumoniae (12.1 percent), E. coli (10.5 percent), and E. cloacae (7.9 percent). Pseudomonas aeruginosa isolates had susceptibility rates of 67.5 percent to piperacillin/tazobactam, 59.8 percent to meropenem, 57.3 percent to imipenem. A. baumannii presented susceptibility rates to meropenem of 89.5 percent, 88.4 percent to imipenem, and 74.4 percent to tobramycin. E. coli and K. pneumoniae were fully susceptible to both carbapenems. CONCLUSIONS: Carbapenem resistance among Enterobacteriaceae is still rare in this region. A. baumannii and P. aeruginosa presented elevated resistance rates to all antimicrobials. Since these two bacterial species play an important role in nosocomial infections, the use of empirical combination therapy to treat these pathogens may be justified.

Impacto da automação no diagnóstico de infecções por micobactérias / Impact of automation in the diagnosis of mycobacterial infection

A tuberculose é uma doença de importância mundial e há alguns anos, em muitos países, foi quase erradicada, mas, com o advento da Aids, novos casos da doença começaram a ocorrer, com o agravante do surgimento de cepas resistentes a diversos antimicrobianos. Concomitante a este aumento na incidência de tuberculose, as metodologias diagnósticas apresentaram avanços consideráveis, e atualmente existem diversas metodologias manuais ou automatizadas para um diagnóstico mais rápido das infecções por micobactérias. Um dos sistemas semi-automatizados, o Bactec 460 (Becton Dickinson Diagnostic Systems, Sparks, MD), é utilizado para detectar a presença de micobactérias em espécimes clínicos, realizar testes de sensibilidade aos antimicrobianos e fazer a diferenciação entre micobactérias do complexo tuberculosis e as não-pertencentes a este complexo, diminuindo o tempo do processo em vários dias. O intuito deste trabalho foi verificar o impacto ocasionado com a introdução de um sistema semi-automatizado na rotina de laboratório. No período de janeiro a junho de 1995, foram processadas, pelo método tradicional de cultura em meio de Lownstein-Jensen (LJ), 326 amostras, das quais 39 (12 por cento) foram positivas, sendo 77 por cento destas identificadas como Mycobacterium tuberculosis. Do total de amostras positivas para M. tuberculosis, 29 (74, 3 por cento) apresentaram um prazo de detecção superior a 30 dias. No mesmo período, no ano de 1997, com a introdução do sistema semi-automatizado, foram processadas 340 amostras, das quais 50 (14,7 por cento) foram positivas, sendo 46 por cento destas identificadas como Mycobacterium tuberculosis. O tempo médio para detecção do crescimento das amostras positivas para M. tuberculosis foi de 12 dias. A implantação do sistema automatizado para culturas proporcionou um aumento no número de isolamento de diferentes espécies, em diversos clínicos, com diminuição no tempo de detecção, além de oferecer maior segurança para os técnicos durante a realização destes procedimentos

Atividade antimicrobiana in vitro de quinupristina/dalfopristina para cocos gram-positivos isolados de cinco centros brasileiros: resultado do estudo de vigilância L-SMART / Antimicrobial in vitro activity of quinupristin/dalfopristin against gram-positive cocci isolated from 5 Brazilian centers: results from the local smart (L-SMART) surveillance study

Há alguns anos tem-se verificado um aumento progressivo da resistência de alguns cocos gram-positivos a determinados antimicrobianos. Este aumento da resistência tem sido observado principalmente no ambiente hospitalar, e as bactérias mais comumente envolvidas são os Staphylococcus spp. e os Enterococcus spp. Devido a este fato, novos antimicrobianos são avaliados para o tratamento de infecções causadas por estas cepas multirresistentes. A associação quinupristina/dalfopristina (Q/D), também conhecida como Synercid©, é um antibacteriano da classe das estreptograminas, de uso endovenoso, composto por dois derivados semi-sintéticos da pristanamicina. A combinação das estreptograminas B e A na razão de 30:70 tem atividade antimicrobiana voltada para cocos gram-positivos, como Staphylococcus spp., Streptococcus spp., incluindo S. pneumoniae e Enterococcus faecium, sendo o E. faecalis habitualmente resistente. Neste estudo foi avaliada atividade in vitro de Q/D e outros oito antimicrobianos frente a 631 amostras de cocos gram-positivos isoladas de cinco centros brasileiros, complementadas com outras 20 cepas de E. faecium resistentes à vancomicina, provenientes dos Estados Unidos. Para a avaliação da sensibilidade aos antimicrobianos foi determinada a concentração inibitória mínima (MIC) pelo método do Etest (AB Biodisk, Solna, Suécia) e as cepas testadas foram: Staphylococcus aureus (n=267), Staphylococcus coagulase negativo (n=131), Streptoccus pneumoniae (n=130), Streptococcus beta-hemolíticos (n=28), Enteroccus faecalis (n=44) e E. faecium (n=51). A Q/D demonstrou excelente atividade contra Staphylococcus spp., independente de serem sensíveis ou resistentes à oxacilina. Para S. pneumoniae, a Q/D apresentou igualmente uma ótima atividade, inclusive para as cepas com resistência intermediária ou total para penicilina. Entre as cepas de E. faecium sensíveis à vancomicina, o MIC 90 de Q/D obtido foi de 3µg/ml, sendo que 45 por cento das cepas testadas foram sensíveis e 55 por cento apresentaram sensibilidade intermediária à associação. Desta forma, pode-se afirmar que a associação. Desta forma, pode-se afirmar que a associação Q/D representa uma nova opção para o tratamento endovenoso de infecções causadas por cocos gram-positivos, principalmente para as cepas multiresistentes, sendo também uma alternativa ao uso de glicopeptídeos

Avaliaçäo in vitro de macrolídeos e antibióticos B-lactâmicos orais ante a microrganismos isolados no tato respiratório / In vitro evaluation of oral macrolides and B-lactam antibiotics against isolated Pathogens from the respiratory tract

No período de setembro de 1999 a julho de 2000, analisamos a atividade in vitro de seis antimicrobianos, respectivamente, azitromicina, claritromicina, amoxicilina, amoxicilina/ácido clavulânico, cefprozil e cefaclor ante a um total de 597 amostras bacterianas isoladas do trato respiratório superior e inferior de pacientes da comunidade, sem restriçäo de faixa etária, assim distribuídas: 247 cepas de H. influenzae, 147 S. aureus, 114 S. pneumoniae, 51 S. pyogenes e 38 M catarrhalis. A determinaçäo da Concentraçäo Inibitória Mínima (MIC) foi realizada pelo método do Etest e interpretadas de acordo com critérios padronizados pelo NCCLS. Entre as 247 cepas de H. influenzae, 9,7 porcento eram produtoras de B-lactamase, sendo que 100 porcento destas cepas foram sensíveis à amoxicilina/ác. clavulânico e cefaclor, 98 porcento à cefprozil, 96 porcento à azitromicina e 90 porcento à claritromicina. Das 147 cepas de S. aureus, 100 porcento eram sensíveis à oxacilina, amoxilina/ác. clavulânico, cefprozil e cefaclor, 71 porcento à claritromicina e 68 porcento à azitromicina. Entre as 114 cepas de S. peneumoniae, nenhuma cepa apresentou resistência total à penicilina, 14 cepas apresentaram resistência intermediária para penicilina, sendo que 100 porcento das cepas foram sensíveis à amoxicilina e amoxicilina/àc. clavulânico, 99 porcento à cefprozil e cefaclor, 88 porcento à azitromicina e 86 porcento à claritromicina. Entre as 14 cepas de pneumococos com resistência intermediária para penicilina, 3 cepas eram resistentes à azitromicina e 4 cepas à claritromicina. Entrre as 51 amostras de S. pyogenes, 4 cepas apresentaram resistência à azitromicina e claritromicina. Para M. catarrhalis, 100 porcento das cepas eram produtoras de B-lactamase e o MIC para azitromicina, claritromicina, amoxicilina, amoxicilina/ác. clavulânico, cefprozil e cefaclor foram 0,25; 0,25; 3; 0,25; 4 e 1,5 ug/ml, respectivamente.(au)

Detection of Mycobacteria in the bloodstream of patients with Acquired Immunodeficiency Syndrome in a University Hospital in Brazil

This study was done to determine the occurrence of mycobacteria in the bloodstreams of patients with fever and advanced AIDS in a Brazilian hospital. We also verified the capability of an automated method for recovering these bacteria. During a period of 19 months, 254 patients with AIDS were evaluated. Blood cultures were generally submitted in pairs and drawn separately. Blood cultures were processed by the BACTEC 460TB System (Becton Dickinson Microbiology Systems, Sparks, MD). Of the 530 vials submitted, 77 (14.5 percent) from 41 (16 percent) patients were positive. Mycobacterium avium complex was recovered from 45 (58.4 percent) of the 77 positive vials, corresponding to 22 (53.6 percent) patients with positive blood cultures. The average time to detect Mycobacterium avium complex was 15 days. Mycobacterium tuberculosis was recovered from 26 (33.8 percent) of the 77 positive vials, corresponding to 15 (36.6 percent) patients with positive blood cultures, with an average detection time of 24 days. Other species of mycobacteria were recovered from 6 (7.8 percent) of the 77 vials, corresponding to 4 (9.8 percent) patients. M. avium complex was fairly prevalent (8.7 percent) in severely ill patients with AIDS in our hospital. M. tuberculosis was also an important (6.0 percent) agent of systemic bacterial infections in these patients. The rapid diagnosis of mycobacteremia was possible with the implementation of this automated technology.

In vitro susceptibility of gram-positive cocci isolated from skin and respiratory tract to azithromycin and twelve other antimicrobial agents

This study was conducted to evaluate the activity of azithromycin in comparison to 112 other antibacterial agents against recent isolates obtained consecutively from patients with respiratory tract or skin infections, from january to july, 2000. A total of 717 gram-positive cocci were analyzed in this study and the following species were studied: staphylococcus aureus (n=576), ß-hemolytic streptococci (n=115), and streptococcus pneumoniae (n=26). Susceptibility testing was carried out by the disk diffusion method and interpreted according to NCCLS breakpoints. The activity of azithromycin was compared to erythromycin, clindamycin, chloramphenicol, ciprofloxacin, ofloxacin, oxacillin, penicillin, ceftriaxone, tetracycline, trimethoprim/sulfamethoxazole, teicoplanin, and vancomycin. Of the 26 S. pneumoniae isolates recovered from the respiratory tract, 5 (19.2 percent) were imediate resistant to penicillin. All of these strains were susceptible to chloramphenicol, ofloxacin, and vancomycin, and 24 (92 percent) were also susceptible to azithromycin, clindamycin, and erythromycin. Among the 67 ß-hemolytic streptococci strains isolated from the respiratory tract, 66 (99 percent) were susceptible to azithromycin, erythromycin, clindamycin, and ofloxacin. All 48 ß-hemolytic streptococci strains isolated from skin were susceptible to azithromycin and clindamycin, 47 (98 percent) were susceptible to erythromycin, and 46 (96 percent) were susceptible to ofloxacin. Of the 576 strains of S. aureus, 253 (43.9 percent) were isolated from the respiratory tract and 323 (56.1 percent) from skin. Among S. aureus isolates from the respiratory tract and skin, 46 (18 percent) and 78 (24 percent), respectively were resistant to oxacillin. Isolates from the respiratory tract and skin showed the same percentage of resistance (36 percent) to azithromycin. These in vitro results suggest that azithromycin can be a therapeutic option for treatment of infections caused by these bacteria since the never macrolides have several distinct advantages over erytromycin including improved oral bioavailability, longer half-life allowing once or twice daily administration, higher tissue concentrations and less gastrointestinal adverse effects.

Sensibilidade aos antimicrobianos de amostras Pseudomonas aeruginosa e acinetobacter spp: dados do programa de vigilância RESISTNET Brasil / Antimicrobial susceptibility of pseudomonas aeruginosa e acinetobacter spp: RESISTNET Brasil surveillance program

O programa RESISTNET é um estudo de vigilância de resistência bacteriana a diversos antimicrobianos. Trata-se de um projeto latino-americano iniciado em abril de 1998. No final de 1999, este programa no Brasil passou a denominar-se RESISTNET Brasil. Um dos principais objetivos deste estudo é gerar dados pontuais, atualizados e confiáveis da atual situaçäo da resistência bacteriana a diversos antimicrobianos. Neste trabalho, apresentamos os resultados obtidos durante 12 meses (janeiro a dezembro de 1999), num total de 705 amostras bacterianas, respectivamente 524 amostras de Pseudomonas aeruginosa e 181 amostras de Acinobacter spp, isoladas de diversos materiais clínicos provenientes de pacientes da comunidade (167 amostras) e hospitalizados (538 amostras) de 13 centros em seis cidades brasileiras (Säo Paulo, Porto Alegre, Curitiba, Brasília, Salvador e Fortaleza). Os isolados foram testados pelo método da difuçäo do disco, de acordo com as normas estipuladas pelo NCCLS (11), aos seguintes antimicrobianos: aztreonam, amicacina, cefepima, ceftazidima, cefoperazona, colistina, ciprofloxacina, gentamicina, imipenem, piperacilina,ticarcilina/ácido clavulânico, amplicilina/sulbactam e tobramicina, Em relaçäo a Pseudonomas aeruginosa, os antimicrobianos mais ativos foram, respectivamente: colistina, imipenem, ceftazidima, cefepima e ciprofloxacina (taxas de sensibilidade de 100 por cento, 78,6 por cento, 77 por cento, 67,6 por cento e 66 por cento). Para Acinobacter spp, os antimicrobianos mais ativos foram: colistina, imipenem, amplicilina/sulbactram e trobamicina (taxas de sensibilidade de 100 por cento, 98,9 por cento, 82,8 por cento e 55,6 por cento respectivamente). As amostras de origem hospitalar apresentaram índices maiores de resistência quando comparadas com as amostras provenientes da comunidade. Os resultados deste levantamento mostram a importância de estudos de resistência aos microbianos, pois estes bacilos Gram negativos näo fermentadores, além de serem responsáveis por diversas infecçöes humanas, mostram significativas taxas de resistência a diversos antimicrobianos