Sensitivity pattern of gram negative bacilli to three beta-lactam/beta-lactamase inhibitor combinations using the automated API system.

PURPOSE: To evaluate the spectrum of activity of three beta-lactamase inhibitors such as amoxicillin/ clavulanic acid, ticarcillin/ clavulanic acid and piperacillin/ tazobactam in comparison to cephalosporins against gram negative bacilli. METHODS: Gram-negative bacilli isolated from the clinical specimens received in the laboratory were included in the study. Using the API system (bioMiotarieux) during a one-year period, a total of 1,252 Enterobacteriaceae and 385 non-fermenters were evaluated. RESULTS: The percentage resistance of the Enterobacteriaceae isolates was 82.92% to amoxicillin/ clavulanic acid, 58.22% to ticarcillin/clavulanic acid and 22.44% to piperacillin/tazobactam respectively. Pseudomonas aeruginosa showed resistance of 96% to ticarcillin/ clavulanic acid and 61% to piperacillin/ tazobactam and Acinetobacter baumannii showed 49% resistance to ticarcillin/ clavulanic acid and 77% resistance to piperacillin/ tazobactam respectively. The isolates exhibited high resistance to all the generations of cephalosporins and the other groups of antibiotics except carbapenems. CONCLUSIONS: Piperacillin/tazobactam was found to be the most active combination of the three against Enterobacteriaceae and Pseudomonas spp. and ticarcillin/clavulanic acid against Acinetobacter spp. and Stenotrophomonas maltophilia.

Comparative in vitro activity of beta-lactam/beta-lactamase inhibitor combinations against gram negative bacteria.

BACKGROUND & OBJECTIVE: Currently, the use of beta-lactamase inhibitors in combination with beta-lactam antibiotics represents an effective measure to combat a specific resistance mechanism of beta-lactamase producing organisms. Knowledge about the susceptibility profile of bacteria to different combination agents available is essential to guide appropriate treatment of severe infections in hospitalized patients. The present study compares the in vitro activity of three commercially available beta-lactam/beta-lactamase inhibitor combinations (piperacillin/tazobactam, cefoperazone/sulbactam, ticarcillin/clavulanic acid) against beta-lactamase producing gram negative bacteria in a tertiary care hospital in north India. METHODS: A total of 9004 consecutively isolated extended spectrum beta-lactamase (ESBL) producing gram negative bacteria isolated from various clinical samples from patients admitted to the All India Institute of Medical Sciences, New Delhi, from September 2003 to August 2004 were included in the study. These isolates were screened for ESBL production by the inhibitor based test recommended by the National Committee for Clinical Laboratory Standards (NCCLS). Antibiotic susceptibility testing was carried out by disc diffusion method as per NCCLS guidelines. RESULTS: Of the 9004 isolates tested, 3232 (35.89%) were sensitive and 568 (6.31%) were resistant to all three combination agents, and rest 5204 (57.80%) were resistant to at least one of the combinations. Susceptibility to piperacillin/tazobactam, cefoperazone/sulbactam, and ticarcillin/clavulanic acid was 81.37, 76.06 and 45.48 per cent respectively. Piperacillin/tazobactam exhibited significantly (P<0.05) greater antimicrobial activity against Pseudomonas spp., Escherichia coli and Klebsiella spp. compared to cefoperazone/sulbactam. INTERPRETATION & CONCLUSION: Overall piperacillin/tazobactam was observed to be the best combination agent followed by cefoperazone/sulbactam in our setting. This difference in activities of these combination agents needs to be evaluated further by ascertaining their efficacy in clinical studies.

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

Susceptibility of clinical isolates of Bacteroides fragilis group strains to cefoxitin, cefoperazone and ticarcillin/clavulanate

A total of 40 strains of the B. fragilis group was isolated from clinical specimens in two hospital centers in Fortaleza from 1993 to 1997. The most frequently isolated species was Bacteroides fragilis (19 strains) and most isolates came from intra-abdominal and wound infections. The susceptibility profile was traced for cefoxitin, cefoperazone and ticarcillin-clavulanate by using the agar dilution reference method. All isolates were susceptible to ticarcillin-clavulanate (128/2mug/ml). Resistance rates of 15 and 70 percent were detected to cefoxitin (64mug/ml) and cefoperazone (64mug/ml), respectively. Such regional results permit a better orientation in choosing this group of antibiotics for prophylaxis and therapy especially in relation to cefoxitin, which is frequently used in the hospital centers studied.

Ticarcilina com clavulanato sensibilidade de amostras bacterianas (1994) / Ticarcillin with clavulanic acid bacterial samples susceptibility (1994)

O estudo avalia 414 amostras bacterianas isoladas no Rio de Janeiro (Brasil) testadas para a associaçäo ticarcilina-clavulanato. Observa-se uma sensibilidade global de 67 por cento para Gram-positivos. Entre micoorganismos mais prevalentes na amostragem estudada encontramos 75 por cento de sensibilidade para Pseudomonas aeruginosa, 70,2 por cento em Escherichia coli, 43,3 por cento em Klebsiella pneumoniae e 86,9 por cento em Staphylococcus aureus. Abrem-se expectativas de utilizaçäo da droga em outros grupos microbianos como Acinetobacter calcoaceticus normalmente ditados de estraordinária resistência bacteriana.+