Ceftolozane-tazobactam activity against drug-resistant Enterobacteriaceae and Pseudomonas aeruginosa causing healthcare-associated infections in Latin America: report from an antimicrobial surveillance program (2013-2015)

ABSTRACT This study evaluated the in vitro activity of ceftolozane-tazobactam and comparator agents tested against Latin American isolates of Enterobacteriaceae and Pseudomonas aeruginosa from patients with health care-associated infections. Ceftolozane-tazobactam is an antipseudomonal cephalosporin combined with a well-established β-lactamase inhibitor.A total of 2415 Gram-negative organisms (537 P. aeruginosa and 1878 Enterobacteriaceae) were consecutively collected in 12 medical centers located in four Latin American countries. The organisms were tested for susceptibility by broth microdilution methods as described by the CLSI M07-A10 document and the results interpreted according to EUCAST and CLSI breakpoint criteria. Results: Ceftolozane-tazobactam (MIC50/90, 0.25/32 µg/mL; 84.2% susceptible) and meropenem (MIC50/90, ≤0.06/0.12 µg/mL; 92.6% susceptible) were the most active compounds tested against Enterobacteriaceae. Among the Enterobacteriaceae isolates tested, 6.6% were carbapenem-resistant Enterobacteriaceae and 26.4% exhibited an extended-spectrum β-lactamase non-carbapenem-resistant phenotype. Whereas ceftolozane-tazobactam showed good activity against extended-spectrum beta-lactamase, non-carbapenem-resistant phenotype strains of Enterobacteriaceae (MIC50/90, 0.5/>32 µg/mL), it lacked useful activity against strains with a (MIC50/90, >32/>32 µg/mL; 1.6% S) carbapenem-resistant phenotype. Ceftolozane-tazobactam was the most potent (MIC50//90, 0.5/16 µg/mL) β-lactam agent tested against P. aeruginosa isolates, inhibiting 86.8% at an MIC of ≤4 µg/mL. P. aeruginosa exhibited high rates of resistance to cefepime (16.0%), ceftazidime (23.6%), meropenem (28.3%), and piperacillin-tazobactam (16.4%). Conclusions: Ceftolozane-tazobactam was the most active β-lactam agent tested against P. aeruginosa and demonstrated higher in vitro activity than available cephalosporins and piperacillin-tazobactam when tested against Enterobacteriaceae.

Susceptibilidad de enterobacterias a piperacilina/tazobactam en un hospital pediátrico de Chile / Enterobacteriaceae susceptibility to piperacillin/tazobactam in a Chilean pediatric hospital

Resumen Introducción: Las enterobacterias son bacilos gram-negativos responsables de infecciones graves en el ser humano. Se reporta una susceptibilidad en Klebsiella pneumoniae de 79,4% a piperacilina/tazobactam (PIP/TAZO) en hospitales pediátricos de Chile, pero según nuestro conocimiento, no existen datos publicados a la fecha respecto a la susceptibilidad de otras enterobacterias a PIP/TAZO en la población pediátrica chilena. Objetivo: Determinar la susceptibilidad in vitro a PIP/TAZO en cepas obtenidas de infecciones por Enterobacteriaceae en un hospital pediátrico de Chile. Material y Método: Estudio descriptivo y prospectivo de cepas de Enterobacteriaceae en Hospital de Niños Roberto del Río (HRRIO) entre 1 de enero de 2013 y el 27 de agosto de 2014. Se definió la susceptibilidad a PIP/TAZO por método de gradiente (E-test®) según puntos de corte CLSI 2014. Resultados: Se incluyeron 163 casos. El promedio de edad fue de 4 años 15 días. 70,6% de sexo femenino. El 79,7% de las cepas fueron aisladas en urocultivos. La susceptibilidad de Enterobacteriaceae a PIP/TAZO fue 95,1% (n = 155). La susceptibilidad intermedia fue 1,8% (n = 3). Discusión: Los aislados estudiados presentan alta susceptibilidad a PIP/TAZO. Este hallazgo puede explicarse por la baja circulación de microrganismos productores de BLEE y el limitado uso de PIP/TAZO en esta población pediátrica.

Introduction: Enterobacteriaceae are a group of gram-negative rods that can cause serious infections in humans. A susceptibility in Klebsiella pneumoniae of 79.4% to piperacillin/tazobactam (PIP/TAZO) is reported in pediatric hospitals in Chile. There is no published data published to date regarding PIP/TAZO susceptibility to other Enterobacteriaceae species in this population. Aim: To measure the in vitro PIP/TAZO susceptibility in Enterobacteriaceae isolates from patients in a pediatric hospital in Chile. Methods: Descriptive and prospective study of Enterobacteriaceae positive cultures from patients assisting to the "Hospital de niños Roberto del Río" (HRRIO) between January 2013 and August 2014. PIP/TAZO susceptibility was established by gradient diffusion method (E-test®) according to the 2014 CLSI standards. Results: 163 cases were included. The average age was 4 years and 15 days. 70.6% were female. 79.7% of samples were urine cultures. PIP/TAZO susceptibility in Enterobacteriaceae was 95.1% (n = 155). The intermediate susceptibility was 1.8% (n = 3). Discussion: The isolates studied present high susceptibility to PIP/TAZO. This finding could be explained by the fact that this population has not been exposed to this antimicrobial therapy and also the low rates for ESBL in pediatric infections.

Susceptibility of Ceftolozane-Tazobactam and Ceftazidime-Avibactam Against a Collection of β-Lactam-Resistant Gram-Negative Bacteria

No abstract available.

Antimicrobial Susceptibility of Clinical Isolates of Bacteroides fragilis Group Organisms Recovered from 2009 to 2012 in a Korean Hospital

BACKGROUND: Periodic monitoring of antimicrobial resistance trends of clinically important anaerobic bacteria such as Bacteroides fragilis group organisms is required. We determined the antimicrobial susceptibilities of clinical isolates of B. fragilis group organisms recovered from 2009 to 2012 in a tertiary-care hospital in Korea. METHODS: A total of 180 nonduplicate clinical isolates of B. fragilis group organisms were collected in a tertiary care hospital. The species were identified by conventional methods: the ATB 32A rapid identification system (bioMerieux, France) and the Vitek MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (bioMerieux). Antimicrobial susceptibility was determined by the CLSI agar dilution method. RESULTS: Imipenem and meropenem resistance rates were 0-6% for B. fragilis group isolates. The rate of resistance to piperacillin-tazobactam was 2% for B. fragilis and 0% for other Bacteroides species, but 17% for B. thetaiotaomicron isolates. High resistance rates to piperacillin (72% and 69%), cefotetan (89% and 58%), and clindamycin (83% and 69%) were observed for B. thetaiotaomicron and other Bacteroides spp. The moxifloxacin resistance rate was 27% for other Bacteroides spp. The MIC50 and MIC90 of tigecycline were 2-4 microg/mL and 8-16 microg/mL, respectively. No isolates were resistant to chloramphenicol or metronidazole. CONCLUSIONS: Imipenem, meropenem, chloramphenicol, and metronidazole remain active against B. fragilis group isolates. Moxifloxacin and tigecycline resistance rates are 2-27% and 8-15% for B. fragilis group isolates, respectively.

Prejuízos nutricionais e distúrbios no padrão de sono de trabalhadores da Enfermagem / Nutritional damages and disturbances in the sleep pattern of nursing workers / Prejuicios nutricionales y alteraciones en los patrones de sueño de los trabajadores de Enfermería

Este artigo apresenta uma revisão integrativa das publicações científicas da última década, que investigaram os hábitos de sono, a ingestão alimentar e o estado nutricional de profissionais de enfermagem. Foram analisados artigos publicados em periódicos nacionais e internacionais no período de 2002 a 2014, disponibilizados na base de dados PubMed/MEDLINE (USA National Library of Medicine), Lilacs / SciELO (Scientific Eletronic Library Online) e Google Acadêmico. Trinta e um artigos preencheram os critérios estabelecidos. Na análise destes estudos foi identificada elevada prevalência de sobrepeso e obesidade, além de uma modificação negativa nos hábitos alimentares, bem como prejuízos na dinâmica do sono dos profissionais da área de enfermagem.

This article presents an integrative review of national and international scientific publications that investigate the sleep habits, the feed intake and nutritional status of nursing professionals. It was analyzed articles published in national and international journals in the period 2002 to 2014 and made available in the database PubMed / MEDLINE (USA National Library of Medicine), Lilacs / SciELO (Scientific Eletronic Library Online) and Google Scholar. Thirty one articles met the criteria. In the analysis of these studies it has been found a high prevalence of overweight and obesity, a negative change in the eating habits, as well as losses in the sleep patterns of nursing professionals.

En este artículo se presenta una revisión integradora de las publicaciones científicas nacionales e internacionales que investigan los hábitos de sueño, el consumo de alimento y el estado nutricional de los profesionales de enfermería. Se analizaron los artículos publicados en revistas nacionales e internacionales en el período de 2002 a 2014, disponibles en la base de datos PubMed / MEDLINE (USA Biblioteca Nacional de Medicina), Lilacs / SciELO (Scientific Eletronic Library Online) y Google Scholar. Treinta y uno artículos cumplieron con los criterios de inclusión. En el análisis de estos estudios se encontró una alta prevalencia de sobrepeso y obesidad, un cambio negativo en los hábitos alimenticios, así como prejuicios en la dinámica del sueño de los profesionales de enfermería.

Pharmacodynamic profiling of commonly prescribed antimicrobial drugs against Escherichia coli isolates from urinary tract

Since antimicrobial resistance among uropathogens against current first line agents has affected the management of severe urinary tract infection, we determined the likelihood that antibiotic regimens achieve bactericidal pharmacodynamic exposures using Monte Carlo simulation for five antimicrobials (ciprofloxacin, ceftriaxone, piperacillin/tazobactam, ertapenem, and meropenem) commonly prescribed as initial empirical treatment of inpatients with severe community acquired urinary tract infections. Minimum inhibitory concentration determination by Etest was performed for 205 Brazilian community urinary tract infection Escherichia coli strains from 2008 to 2012 and 74 E. coli bloodstream strains recovered from a surveillance study. Pharmacodynamic exposure was modeled via a 5000 subject Monte Carlo simulation. All isolates were susceptible to ertapenem and meropenem. Piperacillin/tazobactam, ceftriaxone and ciprofloxacin showed 100%, 97.5% and 83.3% susceptibility among outpatient isolates and 98.6%, 75.7% and 64.3% among inpatient isolates, respectively. Against outpatient isolates, all drugs except ciprofloxacin (82.7% in aggressive and 77.6% in conservative scenarios) achieved high cumulative fraction of response: car-bapenems and piperacillin/tazobactam cumulative fraction of responses were close to 100%, and ceftriaxone cumulative fraction of response was 97.5%. Similar results were observed against inpatients isolates for carbapenems (100%) and piperacillin/tazobactam (98.4%), whereas ceftriaxone achieved only 76.9% bactericidal cumulative fraction of response and ciprofloxacin 61.9% (aggressive scenario) and 56.7% (conservative scenario) respectively. Based on this model, standard doses of beta-lactams were predicted to deliver sufficient pharmacodynamic exposure for outpatients. However, ceftriaxone should be avoided for inpatients and ciprofloxacin empirical prescription should be avoided in both inpatients and outpatients with complicated urinary tract infection.

Actividad inhibitoria de dihidroxifenil propenona sobre betalactamasas de Enterobacter cloacae: estudio preliminar en el desarrollo de fármacos para enfrentar la resistencia bacteriana / Inhibitory activity of dihydroxy-phenyl-propenone on betalactamase of Enterobacter cloacae : Preliminary study for drug development to overcome bacterial resistance

Introducción . Los microorganismos patógenos como Enterobacter cloacae producen betalactamasas que les confieren resistencia frente a los antibióticos betalactámicos; se ha identificado, además, la actividad limitada de los inhibidores enzimáticos, de modo que la única posibilidad de enfrentar la resistencia es el diseño de nuevos fármacos y su uso racional. Objetivo. Evaluar el efecto de la chalcona dihidroxifenil propenona sobre un aislamiento clínico de E. cloacae y sobre la betalactamasa aislada a partir de este microorganismo resistente como un aporte en la búsqueda de compuestos inhibidores de las betalactamasas. Materiales y métodos. Se sintetizó la chalcona dihidroxifenil propenona y se evaluó su efecto sobre el aislamiento clínico de E. cloacae para determinar la concentración inhibitoria mínima mediante el método de microdilución en caldo y con la betalactamasa purificada mediante cromatografía de afinidad se realizaron estudios espectrofotométricos de cinética enzimática. Resultados. La concentración inhibitoria mínima de la dihidroxifenil propenona sobre E. cloacae fue de 35 µg/ml; el porcentaje de recuperación de la betalactamasa a partir del microorganismo fue de 31,75 %; en el estudio cinético se evidenció actividad inhibitoria de acuerdo con los parámetros cinéticos de V max =1,7 x 10 -3 µM/minuto y K M´ =2330 µM. Conclusión. La chalcona dihidroxifenil propenona ejerce su actividad inhibitoria por medio de la interacción con la betalactamasa y, de esta manera, protege la integridad estructural de los antibióticos betalactámicos; dicho efecto sinérgico la convierte en un compuesto promisorio en la búsqueda de alternativas para enfrentar la resistencia bacteriana.

Introduction: Enterobacter cloacae is a pathogenic microorganism with the ability to produce betalactamase enzymes, which makes them resistant to betalactamic antibiotics. Additionally, the limited activity of enzymatic inhibitors has been identified, and, therefore, the design of new drugs and the promotion of their rational use are the only possibilities to overcome this problem. Objective: The aim of this research was to evaluate the effect of dihydroxy-phenyl-propenone on a clinical isolate of E. cloacae , as well as its activity on a betalactamase isolated from this resistant microorganism in order to contribute to the search for new betalactamase inhibitors. Materials and methods: Dihydroxy-phenyl-propenone chalcone was synthesized and evaluated on a clinical isolate of E. cloacae to determine the minimum inhibitory concentration by broth microdilution; once the betalactamase enzyme was purified by affinity chromatography, a spectrophotometric analysis was done to evaluate its kinetic activity. Results: The minimum inhibitory concentration value of dihydroxy-phenyl-propenone on E. cloacae was 35 µg/ml; the recovery percentage of the betalactamase from the microorganism was 31.75% and the kinetic parameters were V max =1.7 x 10 -3 µM/min and K M = 2330 µM, which show an important inhibitory activity. Conclusion: Dihydroxy-phenyl-propenone has shown inhibitory activity on betalactamase enzymes and the ability to protect the chemical integrity of betalactamic antibiotics; this synergistic effect turns it into a promising compound in the search for new alternatives to overcome bacterial resistance.

Capnocytophaga sputigena Bacteremia in a Patient with Chronic Lymphocytic Leukemia

No abstract available.

Detection of stability and degradation of piperacillin and tazobactam in injectables from in-patient wards and pharmacy by RP-HPLC method

New RP-HPLC method for the detection of degradants and quantification piperacillin and tazobactam in injectables stored in inpatient wards and pharmacy has been developed on C[8] column [250 x 4.6, 5 micron] using methanol and water [55:45% v/v] as mobile phase and Diode array detection at 215 nm. Linearity regression coefficients were more than 0.999 and % RSD for intra- and inter-assay precision and accuracy were less than 2. Selectivity of the method for all possible degradants and analytes were established by mild acidic and alkaline stress degradation using 0.001M HCl and 0.001M NaOH. Method was applied on various samples of injectables collected from inpatients wards and pharmacy. Results revealed that few minor degradants were observed in samples collected from refrigerator and 9 degradants were found in samples collected from trays of inpatient ward. Formed degradants were identical with acid/base hydrolytic products of stress studies. This RP-HPLC method is highly reliable in hospitals and clinical analysis of Piperacillin and Tazobactam in Injectables to preserve potency, to prevent resistance and to ensure efficacy. This study educates the paramedical staff in handling and storage of Piperacillin and Tazobactam in injectables in wards and pharmacy stores

Staphylococcal resistance against five groups of life saving antibiotics in the year 2003-2005

In the year 2003 to 2005 a prospective study was conducted to find out the predominance of Staphylococcus [Staphylococcus aureus] resistance pattern in opposition to five life saving antibiotics as these are the sole agents to treat critically ill patients in hospitals. During the period of two years almost 2500 samples of bacterial culture were taken from different pathological laboratories and hospitals in Karachi. Among these 1500 were Gram positive cocci and 1000 samples were identified as Staphylococcus aureus. Life saving antibiotics were taken from five different groups and by mean of disk diffusion technique antibiogram of Staphylococcus aureus against these antibiotic were determined. During the course of study imipenem showed 11%, amikacin exhibited 58%, cefipime showed 31%, vancomycin and piperacillin/tazobactam displayed 24% resistance against Staphylococcus aureus. Imipenem was found to be most effective against Staphylococcus aureus.Resistance to other antibiotics developed quickly in Staphylococcus aureus collected from clinical areas where these antimicrobial agents are extensively used

AmpC β-lactamases in nosocomial isolates of Klebsiella pneumoniae from India.

Background & objectives: AmpC β-lactamases are clinically significant since these confer resistance to cephalosporins in the oxyimino group, 7-α methoxycephalosporins and are not affected by available β-lactamase inhibitors. In this study we looked for both extended spectrum β-lactamases (ESBL) and AmpC β-lactamases in Klebsiella pneumoniae clinical isolates. Methods: One hundred consecutive, non-duplicate clinical isolates of K. pneumoniae collected over a period of one year (June 2008 - June 2009) were included in the study. An antibiotic susceptibility method was used with 10 antibiotics for Gram-negative infections which helped in screening for ESBL and AmpC β-lactamases and also in confirmation of ESBL production. The detection of AmpC β-lactamases was done based on screening and confirmatory tests. For screening, disc diffusion zones of cefoxitin <18 mm was taken as cefoxitin resistant. All cefoxitin resistant isolates were tested further by AmpC disk test and modified three dimensional test. Multiplex-PCR was performed for screening the presence of plasmid-mediated AmpC genes. Results: Of the 100 isolates of K. pneumoniae studied, 48 were resistant to cefoxitin on screening. AmpC disk test was positive in 32 (32%) isolates. This was also confirmed with modified three dimensional test. Indentation indicating strong AmpC producer was observed in 25 isolates whereas little distortion (weak AmpC) was observed in 7 isolates. ESBL detection was confirmed by a modification of double disk synergy test in 56 isolates. Cefepime was the best cephalosporin in synergy with tazobactam for detecting ESBL production in isolates co-producing AmpC β-lactamases. The subsets of isolates phenotypically AmpC β-lactamase positive were subjected to amplification of six different families of AmpC gene using multiplex PCR. The sequence analysis revealed 12 CMY-2 and eight DHA-1 types. Interpretation & conclusions: Tazobactam was the best β-lactamase inhibitor for detecting ESBL in presence of AmpC β-lactamase as this is a very poor inducer of AmpC gene. Amongst cephalosporins, cefepime was the best cephalosporin in detecting ESBL in presence of AmpC β-lactamase as it is least hydrolyzed by AmpC enzymes. Cefepime-tazobactam combination disk test would be a simple and best method in detection of ESBLs in Enterobacteriaceae co-producing AmpC β-lactamase in the routine diagnostic microbiology laboratories.

Urinary tract infection by Chryseobacterium indologenes.

Chryseobacterium species is an uncommon human pathogen although recovered from various sources in the hospital environment. Most infections have been detected in hospitalized patients with severe underlying diseases and who had indwelling devices or implants. Despite their low virulence, chryseobacteria are inherently resistant to many antimicrobial agents. We report a rare case of urinary tract infection by Chryseobacterium indologenes in a young girl, operated for renal calculus and successfully treated with piperacillin-tazobactam combination.

In-Vitro Efficacy of Synergistic Antibiotic Combinations in Multidrug Resistant Pseudomonas Aeruginosa Strains

PURPOSE: Combination antibiotic treatment is preferred in nosocomial infections caused by Pseudomonas aeruginosa (P. aeruginosa). In vitro synergism tests were used to choose the combinations which might be used in clinic. The aim of this study was to investigate the synergistic efficacy of synergistic antibiotic combinations in multidrug resistant P. aeruginosa strains. MATERIALS AND METHODS: Synergistic efficacies of ceftazidime-tobramycin, piperacillin/tazobactam-tobramycin, imipenem-tobramycin, imipenem-isepamycin, imipenem-ciprofloxacin and ciprofloxacin-tobramycin combinations were investigated by checkerboard technique in 12 multiple-resistant and 13 susceptible P. aeruginosa strains. RESULTS: The ratios of synergy were observed in ceftazidime-tobramycin and piperacillin/tazobactam-tobramycin combinations as 67%, and 50%, respectively, in resistant strains, whereas synergy was not detected in other combinations. The ratios of synergy were observed in ceftazidime-tobramycin, piperacillin/tazobactam-tobramycin, imipenem-tobramycin, imipenem-ciprofloxacin and imipenem-isepamycin combinations as 31%, 46%, 15%, 8%, 8%, and respectively, in susceptible strains, whereas synergy was not detected in ciprofloxacin-tobramycin combination. Antagonism was not observed in any of the combinations. CONCLUSION: Although the synergistic ratios were high in combinations with ceftazidime or piperacillin/tazobactam and tobramycin, the concentrations in these combinations could not usually reach clinically available levels. Thus, the solution of the problems caused by multiple resistant P. aeruginosa should be based on the prevention of the development of resistance and spread of the causative agent between patients.

aetiology and antimicrobial susceptibility pattern of the significant blood culture isolates from a district general hospital in England

To report the prevalence of pathogens causing blood stream infections [BSIs] and antibiotic susceptibility profile of blood culture isolates from district general hospital, southeast of England. This study was conducted at Southend Hospital, UK to provide data on common pathogens of BSIs and their susceptibility profiles. The microbiology laboratory information and hospital information systems and patients note records were retrospectively reviewed to determine the clinical significance of BSI isolates and the susceptibility pattern from August 2006 to July 2007. Blood cultures were processed by BACTEC, a continuous monitoring system and blood culture isolates were identified by standard conventional methods. Disc diffusion method was used for susceptibility testing according to the British Society of Antimicrobial Chemotherapy guidelines. A total of 699 isolates were analysed. Gram positive bacteria as a group were the most common cause of BSIs. Escherichia coli accounted for 18.8% [132 strains] of the total blood culture isolates; followed by Staphylococcus aureus [18.2%, 127 isolates], coagulase negative Staphylococcus [10.9%, 76 isolates], Streptococcus species [9.4%, 66 isolates] and Klebsiella species [6.72%, 47 isolates]. Anaerobes accounted for 3.9% of the total BSIs whilst only 19 Candida species were isolated. Antimicrobial sensitivity results showed that the majority of the Gram negative bacteria were sensitive to imipenem, meropenem, piperacillin/tazobactam and gentamicin while vancomycin showed good activity against Gram positive bacterial isolates. Better understanding of local prevalence of pathogens of BSI and their susceptibility profile can improve the efficiency of the empiric therapy. Active surveillance of pathogens causing BSI and their antimicrobial susceptibility patterns should be continuously practiced in healthcare settings in order to prevent the spread of multiresistant pathogens

Comparison of in vitro activities of ceftazidime, piperacillin-tazobactam, and cefoperazone-sulbactam, and the implication on empirical therapy in patients with cancer.

Background: Infection is a common cause of morbidity and mortality in cancer patients. In most of these cases empirical treatment is provided because the focus of infection is not identified. Empiric antibiotics provided to these patients are based on isolates, sensitivity, and on guidelines. Here we have compared three antibiotics recommended as empirical treatment by the Infectious Disease Society of America (IDSA). Aims: To compare the three antibiotic sensitivities for gram negative isolates at our institute. Objective: To choose the optimal antibiotic as the empirical treatment for cancer patients developing infections. Materials and Methods: We collected the data on isolates and antibiotic sensitivity patterns of isolates for ceftazidime, piperacillin + tazobactum, and cefoperazone from the medical oncology department. We subsequently compared the sensitivity of these three antibiotics. Statistical Methods: The isolates were mapped using the WHONET 5.4 software. The analysis was conducted using SPSS 15.0 for Windows. McNemar Chi-square test was used to compare the sensitivity percentages between any two antibiotics. The agreement between the antibiotic and the gold standard was calculated using the Kappa statistic. Two tailed p values were reported. Results: The results showed that there was a difference among sensitivities for these antibiotics. It appears that the sensitivity of ceftazidime was inferior to the two other antibiotics. Also cefoperazone has better sensitivity as compared to piperacillin + tazobactum. Conclusion: In spite of these three antibiotics being recommended by IDSA our data suggest that it should not be followed blindly and local sensitivity data is important for formulating institutional guidelines for using antibiotics.

Galactomannan detection from piperacillin-tazobactam brands available in the Brazilian market

Piperacillin-tazobactam is a broad spectrum antimicrobial agent that can cause false-positive results in the commercial Platelia Aspergillus EIA test. So far, no study has been performed in Latin America to evaluate the clinical implication of this finding. Here we studied the potential for galactomannan detection in piperacillin-tazobactam batches commercialized in the Brazilian market. Five batches from distinct laboratories were tested in duplicate in the Platelia Aspergillus EIA according to the manufacturer's instructions. Only one drug showed crossreaction at a cut-off of 0.5. Human serum was spiked with this particular drug aiming to mimic achievable piperacillin-tazobactam concentrations in the serum. Results were all negative for galactomannan detection, even at high drug concentrations. Results from this pilot study suggest that piperacillin-tazobactam might not be a clinically significant cause of false-positive results in the Platelia Aspergillus EIA test in Brazil.

Resistance Trends of Bacteroides fragilis Group Over an 8-Year Period, 1997-2004, in Korea / 대한진단검사의학회지

BACKGROUND: Bacteroides fragilis group organisms are the most frequently isolated anaerobes in human infections. Increasing resistance to various antimicrobial agents is a significant problem in choosing appropriate antimicrobial agents to treat anaerobic infections. Periodic monitoring of the regional resistance trends of B. fragilis group isolates is needed. METHODS: A total of 466 nonduplicate clinical isolates of B. fragilis group organisms (276 B. fragilis, 106 Bacteroides thetaiotaomicron, and 84 other B. fragilis group organisms) were collected during the 8-yr period from 1997 to 2004 in a Korean university hospital. Minimum inhibitory concentrations to various antimicrobial agents were determined by the CLSI agar dilution method. RESULTS: Eight isolates were resistant to imipenem. Additionally, the resistance rates to cefotetan were decreased in B. thetaiotaomicron, while those for clindamycin were significantly increased compared to the rates found in previous studies. Depending on species, resistance rates were 1-4% for imipenem, 1-6% for piperacillin-tazobactam, 4-11% for cefoxitin, 33-49% for piperacillin, 14-60% for cefotetan, and 51-76% for clindamycin. No isolates were resistant to chloramphenicol or metronidazole. CONCLUSIONS: Piperacillin-tazobactam, cefoxitin, imipenem, chloramphenicol, and metronidazole are still active against B. fragilis group isolates, while clindamycin no longer has a value as an empirical therapeutic agent in Korea. Furthermore, this study identified the first imipenem-resistant B. fragilis group isolates in Korea.

Occurrence of ESBL & Amp-C beta-lactamases & susceptibility to newer antimicrobial agents in complicated UTI.

BACKGROUND & OBJECTIVE: Production of extended spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases are the most common mechanisms of antimicrobial resistance in Gram negative bacilli. A prospective study was undertaken to know the occurrence of ESBL and AmpC producing strains and their antibiotic susceptibilities to newer agents to guide empirical therapy for complicated urinary tract infections. METHODS: Over a period of five months (January to May 2003), organisms grown in pure culture and in significant numbers from urine sample were identified by standard biochemical tests and antibiotic susceptibility determined by disc diffusion method. Gram-negative bacilli that were resistant to third generation cephalosporins, ciprofloxacin and gentamicin/amikacin were defined as highly drug resistant uropathogens (HDRU). HDRU were further tested for ESBL and AmpC phenotypes. RESULTS: Uropathogens were isolated in significant numbers in 1979 (21.8%) of the total 9,072 samples, of which 438(22.1%) were HDRU. Two hundred and five consecutive HDRU isolates were tested for ESBL production and 36.5 per cent were found to be ESBL producers. The highest positivity was found to be in Klebsiella spp. (51.2%), followed by Escherichia coli (40.2%), Enterobacter aerogenes (33.4%) and Pseudomonas aeruginosa (27.9%). Both ESBL producers and non producers showed a high degree resistance to piperacillin (93.1 and 90.9%), amoxycillin-clavulanic acid (93.4 and 90.9%), aztreonam (79.4 and 78%), cefepime (76.7 and 78%), and ampicillin-sulbactam (76.7 and 70.4%). The most effective antibiotics for ESBL producers were imipenem (8.2% resistance), piperacillin-tazobactam (9.5%) and ceftazidime-clavulanic acid (23.2%). Among ESBL non-producers, piperacillin-tazobactam (31.06%), ceftazidime-clavulanic acid (49.2%) and imipenem (11%) were less effective when compared to ESBL producers. Fifty three piperacillin and piperacillin-tazobactam positive and 20 negative isolates were further tested for AmpC production and found that all 53 positive isolates were also positive by for AmpC beta-lactamase. INTERPRETATION & CONCLUSION: Overall, 22.1 per cent of our isolates were highly drug resistant, and ESBL producers could explain only 36.5 per cent of HDRU in our study. Therefore, we assume that AmpC beta-lactamases are more important in our setting. Based on our finding a test using discs containing piperacillin and piperacillin-tazobactam ( PtPc) disc at a distance of 20 mm would act as a useful screening procedure for AmpC production as AmpC beta-lactamase producers are more susceptible to tazobactam as compared to clavulanic acid.