Effect of parasitism of Lernaea cyprinacea on tadpoles of the invasive species Lithobates catesbeianus.

The introduction of invasive species is one of the greatest threats currently faced by natural ecosystems, causing ecological imbalances between native populations and transmission of a variety of diseases. We reported the interaction between two exotic species given by the parasitic infestation of the copepod Lernaea cyprinacea in the early stages of the development of the American bullfrog Lithobates catesbeianus in the central area of Argentina. In this paper we analysed the leukocyte profile of parasitized and non-parasitized tadpoles of L. catesbeianus with L. cyprinacea and their body condition (BC) as biomarkers of the health status of organisms. A total of 27 tadpoles of L. catesbeianus were analysed (12 non-parasitized and 15 parasitized). The lower BC recorded in parasitized organisms show a lower health status in these tadpoles, which could be affecting the metamorphosis and therefore impact at the population level. Leukocyte response of L. catesbeianus tadpoles to the parasitism of L. cyprinacea was found. Mature and immature lymphocyte frequencies and hematocrit were higher in parasitized compared to non-parasitized tadpoles, which is a typical response to the presence of parasites. However, eosinophils and monocytes were recorded at high frequencies in not parasitized tadpoles, which could be due to the important role played by these leucocytes in the metamorphosis of frogs. The results of this study constitute a first antecedent on leukocyte profile in aquatic stages of anurans during an ectoparasitosis and its possible implications for environmental health. The parasitism of L. cyprinacea influences the biology of the American bullfrog at both the individual and population levels. Parasitized individuals are not killed directly by the parasite, but they can create conditions for secondary infections, growth retardation, behavioral changes and, ultimately, reduce populations.

In vivo horizontal dissemination of the blaKPC-2 gene carried on diverse genetic platforms among clinical isolates of Enterobacteriaceae.

This study investigated the molecular characteristics of six blaKPC-positive Enterobacteriaceae recovered from three patients in Argentina. Antimicrobial susceptibility testing was performed following Clinical and Laboratory Standards Institute (CLSI) 2014 recommendations. Molecular characterisation of the isolates was performed by biparental conjugation, PCR, sequencing, S1 nuclease restriction, and Southern blot hybridisation with a blaKPC probe using standard protocols and conditions. The isolates studied were as follows. Case 1: Escherichia coli (ECO-P1) and Klebsiella pneumoniae (KPN-P1) isolated from a rectal swab harboured blaKPC-2 in transposon Tn4401a on non-typeable and non-conjugative plasmids. Case 2: Enterobacter cloacae (ECL-P2) and K. pneumoniae (KPN-P2) were isolated from two blood cultures. blaKPC-2 was found in a novel genetic variant of ISKpn8-blaKPC-2-ISKpn6-like on conjugative plasmids of IncL/M type. Case 3, Citrobacter freundii (CFR-P3) and Klebsiella oxytoca (KOX-P3) were isolated from skin and skin-structure infection. The blaKPC gene was detected on ISKpn8-ΔblaTEM-blaKPC-2-ISKpn6-like located on an IncA/C conjugative plasmid. CFR-P3 and KOX-P3 harboured blaPER-2 in addition to the blaKPC gene. In conclusion, we document the horizontal dissemination of blaKPC-2 from diverse Enterobacteriaceae clinical isolates with different genetic backgrounds. This is the first report of E. coli harbouring blaKPC associated with Tn4401a in Argentina.

Identificación prequirúrgica de pares craneales en tumores de la base del cráneo mediante la técnica de tensor de difusión

Objetivo: El objetivo de este trabajo es demostrar la utilidad de las técnicas de tensor de difusión de alta densidad (DTI 32 direcciones) para visualizar el trayecto de los pares craneales antes de la cirugía en pacientes con patología tumoral de la base del cráneo. Materiales y métodos: Se estudiaron 26 pacientes con patología tumoral de la base del cráneo con secuencias de tensor de difusión de alta densidad. Los resultados imagenológicos fueron correlacionados con los hallazgos intraoperatorios. Resultados: En todos los pacientes estudiados fue posible la identificación prequirúrgica del recorrido de los nervios involucrados por las lesiones de la base del cráneo y también hubo una correlación entre los datos obtenidos mediante las imágenes y los hallazgos intraoperatorios. Conclusión: La visualización del recorrido de los nervios craneales mediante la difusión de alta densidad demostró ser segura y reproducible para identificar los pares y su recorrido.(AU)

Objective: The objective of this work is to demonstrate the usefulness of high density diffusion tensor imaging techniques (HD-DTI 32 directions), to visualize the course of the cranial nerves prior to surgery in patients with skull base tumor disease. Materials and methods: Twenty-six patients with skull base tumor disease were studied with sequences of high density diffusion tensor imaging. The imaging results were correlated with the intra-operative fi ndings. Results: Pre-surgical identifi cation of the course of the nerves affected by the injuries of the skull base was possible in all the studied patients, with the imaging results correlating with the intraoperative fi ndings. Conclusion: The visualization of the course of the cranial nerves with high density diffusion tensor imaging was shown to be safe and reproducible for the identifi cation of cranial nerves and their course.(AU)

Identificación prequirúrgica de pares craneales en tumores de la base del cráneo mediante la técnica de tensor de difusión / Diffusion tensor technique as a preoperative identification of cranial nerves in skull base tumors

Objetivo: El objetivo de este trabajo es demostrar la utilidad de las técnicas de tensor de difusión de alta densidad (DTI 32 direcciones) para visualizar el trayecto de los pares craneales antes de la cirugía en pacientes con patología tumoral de la base del cráneo. Materiales y métodos: Se estudiaron 26 pacientes con patología tumoral de la base del cráneo con secuencias de tensor de difusión de alta densidad. Los resultados imagenológicos fueron correlacionados con los hallazgos intraoperatorios. Resultados: En todos los pacientes estudiados fue posible la identificación prequirúrgica del recorrido de los nervios involucrados por las lesiones de la base del cráneo y también hubo una correlación entre los datos obtenidos mediante las imágenes y los hallazgos intraoperatorios. Conclusión: La visualización del recorrido de los nervios craneales mediante la difusión de alta densidad demostró ser segura y reproducible para identificar los pares y su recorrido...

Objective: The objective of this work is to demonstrate the usefulness of high density diffusion tensor imaging techniques (HD-DTI 32 directions), to visualize the course of the cranial nerves prior to surgery in patients with skull base tumor disease.Materials and methods: Twenty-six patients with skull base tumor disease were studied with sequences of high density diffusion tensor imaging. The imaging results were correlated with the intra-operative fi ndings.Results: Pre-surgical identifi cation of the course of the nerves affected by the injuries of the skull base was possible in all the studied patients, with the imaging results correlating with the intraoperative fi ndings.Conclusion: The visualization of the course of the cranial nerves with high density diffusion tensor imaging was shown to be safe and reproducible for the identifi cation of cranial nerves and their course...

Susceptibility trends of Bacteroides fragilis group isolates from Buenos Aires, Argentina.

The aim of this study was to analyze the susceptibility trends to seven antibiotics of Bacteroides fragilis group isolates based on three survey studies performed by the Committee of Anaerobic Bacteria between 1989 and 2002. Fifty three, 82 and 65 B. fragilis group isolates were collected during each period. The antimicrobial agents included were: ampicillin, ampicillin-sulbactam (2:1), cefoxitin, piperacillin, imipenem, clindamycin, and metronidazole. Minimal inhibitory concentrations (MICs) were determined according to the reference agar dilution method described by the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS). The most active antibiotics for B. fragilis and non-B. fragilis species throughout the three periods were: imipenem with 99.1 and 100% of activity, respectively, and metronidazole with 100% of activity. The susceptibility to ampicillin-sulbactam showed a decrease, from 100% to 90.3% and to 82.4 % in the last period, for both B. fragilis and non-B. fragilis species, respectively. The overall susceptibility rates for cefoxitin, piperacillin, and clindamycin were significantly different between B. fragilis and non-B. fragilis species (84.2% vs. 56.5%; 85.9% vs. 66.7% and 88.8% vs. 64.7%, respectively, p < 0.05). Cefoxitin was the antibiotic that showed more variations as regards periods and species. The susceptibility rates for clindamycin were low, about 60%, for non-B. fragilis species during the last two periods. The variations observed in the susceptibility patterns of the B. fragilis group isolates emphasize the need to continue monitoring the emergence of resistance in order to guide the election of the most appropriate antibiotic therapy scheme for anaerobic infections.

Recovery and characterization of the humate-like salified polymeric organic fraction (lignimerin) from Kraft cellulose mill wastewater.

A dark and complex salified organic polymeric mixture, named lignimerin, was for the first time recovered from Kraft cellulose mill wastewater (KCMW) and characterized by chemical, spectroscopic and relative molecular weight (RMW) analysis. Lignimerin proved to be composed of polyphenols (57.00%), carbohydrates (22.26%) and proteins (7.42%). It also contained metals (6.93%), mainly Ca and, to much lower extent, Mg, Na, Al, Fe, K, Mn, Zn and Cu, bound to the carboxylate and phenate groups. The distribution of lignimerin RMW was assessed to be approximately between 1000 and 8600Da, as well as to consist of lignin and tannin, protein and polysaccharide moieties, strongly aggregated each other. H-lignimerin, its acid derivative, revealed a chemical composition and a RMW distribution very close to that of lignimerin, but a marked metal cations decreasing (1.60%) with respect to lignimerin (6.93%). The humic acid-like nature of both the polymers was assessed. Their potential use as bio-adsorbents of heavy metals is briefly discussed.

Multidrug-resistant tuberculosis in bone marrow transplant recipient.

Multidrug-resistant tuberculosis (TB) is an increasing problem worldwide, however only three cases have been previously described in transplant recipients, especially involving lung and heart transplant. We describe a case of multidrug-resistant TB in an allogenic bone marrow transplant recipient with good response to second-line therapy.

Effect of alendronate on bone mineral density in Puerto Rican males with osteoporosis

Osteoporosis in men was not recognized as a major health problem until recently, and increased research in this area resulted in the approval of alendronate for the treatment of osteoporosis in men at the beginning of this decade. Low bone mineral density (BMD) has been demonstrated to be a strong predictor of fracture in men as it is in women. The causes of osteoporosis in men are variable and can be classified as primary or secondary. The aim of these report is to present the response of BMD in 10 Puerto Rican men with secondary causes of osteoporosis treated with alendronate. A significant increase of BMD in spine, total hip, trochanter and intertrochanteric regions were noted. A non-significant increase in femoral neck was observed.

["In vitro" activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002]. / Actividad "in vitro" de 10 antimicrobianos frente a bacterias anaerobias. Estudio multicéntrico, 1999-2002.

The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroides fragilis group (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), other clostridia (12), and gram-positive cocci (22). The MICs were determined by the agar dilution method according to NCCLS document M11-A5. Metronidazole and piperacillin-tazobactam were the most active antimicrobial agents tested and exhibited MIC90 values of < or = 2 microg/ml and < or = 4 microg/ml against gram-negative organisms, and < or = 2 microg/ml, and < or = 8 microg/ml against gram-positive organisms, respectively. Among beta-lactams the activity against gram-negative rods was in the following order: imipenem > piperacillin > cefoxitin > ceftriaxone > ampicillin. Among the gram-positive bacteria the decreased activity was: piperacillin > imipenem > cefoxitin > ceftriaxone > ampicillin. The majority of the species studied showed different degrees of resistance to clindamycin and azitromycin. Nevertheless, 90% of Fusobacterium nucleatum and Porphyromonas spp. isolates were inhibited by 0.125 mg/ml of clindamycin and azitromycin, respectively.

Actividad “in vitro” de 10 antimicrobianos frente a bacterias anaerobias: Estudio multicéntrico, 1999-2002 / “In vitro” activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002

Se evaluó la actividad de ampicilina, ampicilina-sulbactama, cefoxitina, ceftriaxona, imipenem, piperacilina, piperacilina-tazobactama, clindamicina, metronidazol y azitromicina frente a 166 cepas de bacterias anaerobias aisladas en 8 hospitales de Buenos Aires. Se estudiaron: Bacteroides grupo fragilis (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), otros clostridios (12) y cocos gram-positivos (22). Las CIMs se determinaron usando el método patrón de dilución en agar recomendado por el NCCLS, documento M11-A5. Los antibióticos más activos fueron metronidazol y piperacilina-tazobactama que exhibieron valores de CIM90£ 2 µg/ml y £ 4 µg/ml frente a los microorganismos gram-negativos y £ 2 µg/ml y £ 8 µg/ml frente a los microorganismos gram-positivos, respectivamente. Entre los b-lactámicos el orden de actividad frente a bacilos gram-negativos fue: imipenem > piperacilina > cefoxitina > ceftriaxona > ampicilina. En gram-positivos la actividad decreciente fue: piperacilina> imipenem > cefoxitina > ceftriaxona > ampicilina. La mayoría de las especies estudiadas mostraron distintos niveles de resistencia con clindamicina y azitromicina. Sin embargo, el 90% de las cepas de Fusobacterium nucleatum y Por-phyromonas spp. fue inhibido por una concentración de 0,125 µg/ml de clindamicina y azitromicina, respectivamente.

The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroidesfragilis group (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), other clostridia (12), and gram-positive cocci (22). The MICs were determined by the agar dilution method according to NCCLS document M11-A5. Metronidazole and piperacillin-tazobactam were the most active antimicrobial agents tested and exhibited MIC90values of £ 2 µg/ml and £ 4 µg/ml against gram-negative organisms, and £ 2 µg/ml, and £ 8 µg/ml against gram-positive organisms, respectively. Among b-lactams the activity against gram-negative rods was in the following order: imipenem> piperacillin > cefoxitin > ceftriaxone > ampicillin. Among the gram-positive bacteria the decreased activity was: piperacillin> imipenem> cefoxitin > ceftriaxone > ampicillin. The majority of the species studied showed different degrees of resistance to clindamycin and azitromycin. Nevertheless, 90% of Fusobacterium nucleatum and Porphyromonas spp. isolates were inhibited by 0.125 mg/ml of clindamycin and azitromycin, respectively.

Actividad [quot ]in vitro[quot ] de 10 antimicrobianos frente a bacterias anaerobias. Estudio multicéntrico, 1999-2002 / [[quot ]In vitro[quot ] activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002]

The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroides fragilis group (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), other clostridia (12), and gram-positive cocci (22). The MICs were determined by the agar dilution method according to NCCLS document M11-A5. Metronidazole and piperacillin-tazobactam were the most active antimicrobial agents tested and exhibited MIC90 values of piperacillin > cefoxitin > ceftriaxone > ampicillin. Among the gram-positive bacteria the decreased activity was: piperacillin > imipenem > cefoxitin > ceftriaxone > ampicillin. The majority of the species studied showed different degrees of resistance to clindamycin and azitromycin. Nevertheless, 90

of Fusobacterium nucleatum and Porphyromonas spp. isolates were inhibited by 0.125 mg/ml of clindamycin and azitromycin, respectively.

Hereditary and acquired angioedema: experience with patients in Puerto Rico

Hereditary (HAE) and acquired (AAE) angioedema are vascular reactions involving the sub mucosal tissues, representing localized edema caused by dilatation and increased permeability of the capillaries. HAE and AAE are clinical disorders characterized by angioedema that require prompt differentiation from other causes of angioedema in order to receive the most pertinent and effective therapeutic interventions. The aim of this report is to describe the clinical characteristics of patients with both HAE and AAE identified and followed at the Immunology Clinic of the University Hospital at the Puerto Rico Medical Center, their response and side effects to danazol therapy and their comparison with other series of similar patients reported in the literature. Overall, the patients in this sample presented a similar clinical profile compared to other reported series in the literature.

Actividad [quot ]in vitro[quot ] de 10 antimicrobianos frente a bacterias anaerobias. Estudio multicéntrico, 1999-2002. / [[quot ]In vitro[quot ] activity of ten antimicrobial agents against anaerobic bacteria. A collaborative study, 1999-2002]

The antimicrobial activity of ampicillin, ampicillin-sulbactam, cefoxitin, ceftriaxone, imipenem, piperacillin, piperacillin-tazobactam, clindamycin, metronidazole, and azitromycin was assesed against 166 strains of anaerobic bacteria recovered from eight hospitals in Buenos Aires. The strains studied were Bacteroides fragilis group (65), Fusobacterium spp. (26), Prevotella spp. (21), Porphyromonas spp. (10), Clostridium difficile (10), other clostridia (12), and gram-positive cocci (22). The MICs were determined by the agar dilution method according to NCCLS document M11-A5. Metronidazole and piperacillin-tazobactam were the most active antimicrobial agents tested and exhibited MIC90 values of < or = 2 microg/ml and < or = 4 microg/ml against gram-negative organisms, and < or = 2 microg/ml, and < or = 8 microg/ml against gram-positive organisms, respectively. Among beta-lactams the activity against gram-negative rods was in the following order: imipenem > piperacillin > cefoxitin > ceftriaxone > ampicillin. Among the gram-positive bacteria the decreased activity was: piperacillin > imipenem > cefoxitin > ceftriaxone > ampicillin. The majority of the species studied showed different degrees of resistance to clindamycin and azitromycin. Nevertheless, 90

of Fusobacterium nucleatum and Porphyromonas spp. isolates were inhibited by 0.125 mg/ml of clindamycin and azitromycin, respectively.

Microcirculatory changes in travelers to a tropical country.

BACKGROUND: Travelers to tropical areas seem to be affected by nonhealing leg ulcers more frequently. One of the factors that can affect wound healing in a negative manner is leg edema. This study was performed to determine whether there is increased leg edema in travelers to tropical areas. METHOD: In this study, we measured the capillary filtration rate (CFR) of the lower leg by strain gauge plethysmography, as a measure of leg edema, on location in Surinam. Three groups were included: A, travelers in the first few weeks after arrival; B, travelers who had stayed in the tropics for a minimum of 2 months; C, native inhabitants. RESULTS: The mean CFR (mL/100 mL tissue/min) was significantly higher in group A than in groups B and C; the difference between groups B and C was not significant (group A 0.05 mL/100 mL tissue/min (standard deviation (SD), 0.03) vs. group B 0.02 mL/100 mL tissue/min (SD, 0.02), P = 0.01, and vs. group C 0.02 mL/100 mL tissue/min (SD, 0.02), P = 0.01). CONCLUSIONS: Travelers to tropical areas are affected by increased CFR in the first few weeks after arrival. A prolonged stay leads to the normalization of the CFR. Compression therapy is recommended for travelers to the tropics.

Detección universal de hipoacusias en recién nacidos / Universal detection of hearing loss in newborns

El objetivo de este trabajo de investigación es demostrar la importancia de la detección temprana de hipoacusias en recién nacidos, para evitar posteriores alteraciones linguisticas, sociales y cognitivas en los niños, realizando para tal fin screening universal y búsqueda activa de alteraciones auditivas en neonatos. Se aplicaron métodos subjetivos como también electrofisiológicos, con una prevalencia de hipoacusia neurosensorial bilateral severa o profunda del 2,5 al 3 por ciento. Los resultados obtenidos demostraron que si bien existen diferencias de opinión considerables en relación a especificidad y sensibilidad de las téncias disponibles, un examen subjetivo aplicado en el momento exacto y por profesionales capacitados nos ofrece también alto grado de especificidad y sensibilidad como primer método de rastreo

Random bond XXZ chains with modulated couplings

The magnetization behavior of q-periodic antiferromagnetic spin- 1/2 Heisenberg chains under uniform magnetic fields is investigated in a background of disorder exchange distributions. By means of both real space decimation procedures and numerical diagonalizations in XX chains, it is found that for binary disorder the magnetization exhibits wide plateaus at values of 1+2(p-1)/q, where p is the disorder strength. In contrast, no spin gaps are observed in the presence of continuous exchange distributions. We also study the magnetic susceptibility at low magnetic fields.

Allozyme variation and divergence in the phyllotine rodent Calomys hummelincki (Husson, 1960).

The aim of the present study was to assess the degree of genetic variation and divergence among six populations of Calomys hummelincki, a phyllotine rodent distributed in northern South America. With this information we will try to evaluate the two hypotheses of possible colonization and differentiation of this group of rodents postulated by Baskin and Reig. We studied 34 loci by electrophoretic analysis: 21 were monomorphic for all populations and 13 were polymorphic in at least one population, being P1% = 21.6% the mean value for all populations. The mean value of heterozygosity per locus was H = 0.075. Low values of genetic distance were observed among populations of the Llanos region (0.001 < D < 0.006). There was a larger genetic distance (D = 0.024) between the population from Isiro, in the northwestern semiarid region, and those from the Llanos region. The insular population of Aruba displayed the lowest value of genetic distance with the population from Isiro (D=0.014). The specimens from Sipao, on the right side of the Orinoco river, displayed the highest values of genetic distances in comparison with other populations of C. hummelincki (0.070 < D < 0.095). The relatively high differentiation was due to the fixation of new alleles, not found in other populations of C. hummelincki, at loci Idh-1 and Est-2. F-statistics and Nm values indicated reduced gene flow among the populations sampled. Despite the limited data, the results seem to support Reig's hypothesis about south to north colonization of genus Calomys in South America.

Survival of Acinetobacter baumannii on bed rails during an outbreak and during sporadic cases.

Genotypic methods showed Acinetobacter baumannii biotype 9 genotype I to be the epidemic strain on an outbreak in an intensive care unit (ICU) which lasted from January to April of 1996. A cohort was established during March in which hospital personnel were assigned exclusively to A. baumannii infected or colonized patients. New patients were not admitted to the ICU until the last infected patient was discharged. However, strain I was isolated during April and vectors other than human carriage were suspected. The ICU comprised four sections; patients and beds were moved within them according the severity of diseases. Strain I was isolated from a bed rail nine days after the infected patient was discharged. This dry vector may explain the transmission of the epidemic strain between sections. The following July, four new infected patients were identified and three different strains, including the epidemic one, were recovered. The two other strains were also isolated from a bed rail. Although this environmental source does not explain by itself the transmission of an epidemic strain, it illustrates that dry vectors can be secondary reservoirs where A. baumannii can survive.

Incarcerated obturator hernia successfully treated by laparoscopy.

Obturator hernia is extremely rare and represents a therapeutic and diagnostic challenge. The diagnosis is infrequently made preoperatively because of the nonspecific clinical and radiologic signs that in turn delay the surgical treatment, which is responsible for the known increase in morbidity and mortality. Herein a case is presented of a patient with an incarcerated obturator hernia that was diagnosed and successfully treated using laparoscopic surgery.

Broth disk elution method for anaerobic bacteria: a collaborative study to assess its reliability for clinical purposes.

A collaborative study involving seven laboratories was undertaken to evaluate the reproducibility and the reliability of the broth disk elution test against anaerobic bacteria by comparing with the reference agar dilution method. A two breakpoint broth test was also evaluated. Assays were performed using the same testing conditions (i.e. medium, temperature, atmosphere and incubation time). One hundred Gram-negative and Gram-positive clinical isolates were initially studied. Overall agreement of 98.5% and 97.5%, were found for disk elution and the two breakpoint tests, respectively. In order to assess the reliability of the disk elution test, two different lots (LOT1 and LOT2) of disks of piperacillin and clindamycin were selected, to obtain two final concentrations after dilution (10 and 60 mg/mL; 1 and 4 mg/mL, respectively). Two hundred and eighty assays were performed against one strain of both Bacteroides fragilis(piperacillin MIC, 8.0 mg/mL; clindamycin MIC, <0.5 mg/mL) and Bacteroides thetaiotaomicron(piperacillin MIC, 16.0 mg/mL; clindamycin MIC, <0.5 mg/mL). With LOT 1, considering both species and both antibiotics, the agreement among six laboratories ranged from 85% to 100% (P > 0.05) with the higher concentration. Overall agreement among all laboratories was 91%. No optimal agreement (>90%) for clindamycin-Bacteroides thetaiotaomicron using the LOT1 (77%) was found. Since this finding was not observed with LOT2 (100% agreement), discrepancies were attributed to variation between lots. Overall agreement with LOT2 was 100% for all centres. The present study indicates that the broth disk elution method proved to be a reliable and suitable alternative for routine susceptibility testing for anaerobic bacteria, as a resistance screening method for clinical purposes.