5-Nitroimidazole refractory giardiasis is common in Matanzas, Cuba and effectively treated by secnidazole plus high-dose mebendazole or quinacrine: a prospective observational cohort study.

OBJECTIVE: To evaluate the effectiveness and tolerability of secnidazole combined with high-dose mebendazole for treatment of 5-nitroimidazole-resistant giardiasis. METHOD: Adults with microscopically verified Giardia intestinalis monoinfection attending a secondary level hospital in Matanzas City, Cuba were prospectively included in a cohort. A recently introduced treatment ladder consisting of metronidazole as first-line treatment, followed by secnidazole, tinidazole, secnidazole plus mebendazole and quinacrine as second-to fifth-line treatments, respectively, was used. Adverse events and treatment success were determined by questioning and microscopy on concentrated stool samples, respectively on days 3, 5 and 7 after the end of treatment. If G. intestinalis was detected on day 3, 5 or 7, then the infection was classified as refractory and no further microscopy was performed. RESULTS: A total of 456 individuals were included. Metronidazole, 500 mg three times daily for 5 days, cured 248/456 (54%) patients. A single 2-g secnidazole dose as second-line treatment cured 50/208 (24%) patients. A single 2-g tinidazole dose as third-line treatment cured 43/158 (27%) patients. Three rounds of 5-nitroimidazole therapy therefore cured 341/456 (75%) patients. Secnidazole plus mebendazole (200 mg every 8 hours for 3 days) cured 100/115 (87%) of nitroimidazole refractory infections. Quinacrine cured the remaining 15 patients. All treatments were well tolerated. CONCLUSIONS: 5-Nitroimidazole refractory giardiasis was common, indicating that an alternative first-line treatment may be needed. Retreatment of metronidazole refractory giardiasis with an alternative 5-nitroimidazole was suboptimal, indicating cross-resistance. Mebendazole plus secnidazole were well tolerated and effective for the treatment of 5-nitroimidazole refractory G. intestinalis infection in this setting.

Antimicrobial resistance, diarrheagenic and avian pathogenic virulence genes in Escherichia coli from poultry feed and the ingredients / Resistência antimicrobiana, genes de virulência diarreiogênicos e patogênicos para aves em Escherichia coli isoladas de ingredientes e ração de frangos

Diarrheagenic (DEC) and avian pathogenic Escherichia coli (APEC) are associated with intestinal and extra-intestinal infections (ExPEC), respectively. We aimed to analyze the antimicrobial susceptibility, gene encoding virulence factors associated to DEC and APEC, and phylogenetic classification in E. coli isolated from 320 samples of feed and ingredients. Antimicrobial susceptibility was performed using the disk diffusion method and Multiple Antibiotic Resistance (MAR) Index and Multi-Drug Resistance (MDR) were calculated. Phylogenetic classification was performed on samples harboring DEC and/or APEC virulence-associated genes. A total of 110 E. coli strains were isolated in 15% (49/320) of the evaluated inputs (n=13 vegetable meal; n=33 animal meal, n=3 feed). In general, the isolates showed the highest rates of antimicrobial resistance to sulfonamide and cefazolin and 18% (20/110) were multi-drug resistant. MAR index of feed samples was the highest (0.467). Six and five strains had APEC and DEC virulence-associated genes, respectively, and belonging to phylogenetic groups A and B1. These findings point to the need for strict microbiological control during the production process of these foods.(AU)

Escherichia coli diarreiogênicas (DEC) e patogênicas para aves (APEC) são associadas a infecções intestinais e extraintestinais (ExPEC), respectivamente. O objetivo do presente trabalho foi avaliar a sensibilidade antimicrobiana, a presença de genes que codificam os fatores de virulência relacionados à DEC e APEC, e a classificação filogenética em E. coli isoladas de 320 amostras de ração para frangos e ingredientes. A sensibilidade antimicrobiana foi determinada pelo método disco-difusão e calculou-se o índice de resistência múltipla aos antimicrobianos (IRMA) e a resistência a múltiplas drogas (MDR). Nas amostras que possuíam genes de virulência relacionados à DEC e/ou APEC, foi realizada a classificação filogenética. Foram isoladas 110 amostras de E. coli em 15% (49/320) dos insumos avaliados (n=13 farelos vegetais; n=33 farinhas de origem animal; n=3 rações). De forma geral, os isolados apresentaram as maiores frequências de resistência antimicrobiana à sulfonamida e à cefazolina e 18% (20/110) foram resistentes a múltiplas drogas. O IRMA das rações foi o mais alto (0,467). Os genes que codificam fatores de virulência associados à APEC e DEC foram detectados em seis e cinco isolados, respectivamente, pertencentes aos grupos filogenéticos A e B1. Os resultados demonstram a necessidade de rigoroso controle microbiológico durante o processo de produção desses alimentos.(AU)

Establishment of a pathogenicity index in Salmonella Enteritidis and Salmonella Typhimurium strains inoculated in one-day-old broiler chicks / Estabelecimento de um índice de patogenicidade em cepas de Salmonella Enteritidis e Salmonella Typhimurium inoculadas em pintos de um dia de idade

Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and presence of lesions such as aerosaculitis (A), perihepatitis (Ph), pericarditis (Pc), peritonitis (Pt), onfalitis (O) and cellulitis (C) were registered daily for seven days. From the second to the seventh day there was a proportional decrease in the punctuation of the time of death (TD) for each day that the bird had survived. The pathogenicity index was calculated using the following formula: PI = (TD x 5) + A + Ph + Pc + Pt + O + C. The obtainment of the PI of each bacterial sample was achieved by calculating the rate of the ten inoculated birds. Based on the obtained results, it was possible to attribute the pathogenicity value for each strain, which enabled us to classify them in groups of low (27/200), intermediate (95/200) and high (78/200) pathogenicity. The utilization of standards like time of death and presence of septicemic lesions made it possible to determine the pathogenicity rate for each strain. Besides that, the proposed model has presented dramatic differences between the high, intermediate and low pathogenicity groups, which makes this mechanism useful for further classification of strains isolated in poultry farms.

Salmonella Enteritidis e Salmonella Typhimurium são responsáveis por imensos prejuízos econômicos ao setor avícola, podendo levar ao desenvolvimento de doença clínica e ao aumento da mortalidade em aves jovens. A patogenicidade de Salmonella é considerada complexa e multifatorial, necessitando de estudos que possam esclarecer a interação entre patógeno e hospedeiro. O presente trabalho teve por objetivo avaliar a virulência de 130 isolados de S. Enteritidis e 70 de S.Typhimurium, inoculadas em pintos de um dia de idade, por meio do estabelecimento de um índice de patogenicidade. Para cada cepa, foram utilizados 10 pintos comerciais da linhagem Cobb. As aves foram inoculadas com 200µL de uma solução contendo 2x108 UFC de S. Enteritidis ou S. Typhimurium, por via intraperitoneal. A mortalidade e a presença de lesões como aerossaculite (A), peri-hepatite (Ph), pericardite (Pc), peritonite (Pt), onfalite (O) e celulite (C) foram registradas diariamente durante sete dias. Do segundo ao sétimo dia, houve uma diminuição proporcional da pontuação no tempo de morte (TM) a cada dia em que o animal sobrevivia. O cálculo do índice de patogenicidade de cada pintinho inoculado (IP) obedeceu à seguinte fórmula: IP = (TMx5) + A + Ph + Pc + Pt + O + C. Para obtenção do IP de cada amostra, foi realizada a média do IP obtido com as 10 aves inoculadas. Com base nos resultados observados, foi possível atribuir um valor de patogenicidade a cada uma das cepas, permitindo classificá-las em grupos de baixa (27/200), intermediária (95/200) e alta patogenicidade (78/200). A utilização de critérios, como tempo de morte e presença de lesões septicêmicas, permitiu a determinação de um índice de patogenicidade para cada cepa. Além disso, o modelo proposto apresentou diferença significativa entre os grupos de alta, intermediária e baixa patogenicidade, permitindo, assim, a sua aplicação para classificação futura das cepas isoladas em granjas avícolas.

A randomized, controlled, open-label trial evaluating the efficacy and safety of chloroquine in the treatment of giardiasis in children

BACKGROUND: Giardia duodenalis is among the commonest protozoan parasites in the intestinal tract of humans and may cause significant morbidity worldwide. Although there are several antigiardial agents, treatment failures have been commonly reported.OBJECTIVE: To compare the efficacy and safety of chloroquine (CQ) versus metronidazole (MTZ) in the treatment of children with confirmed G duodenalis mono-infection. METHODS: A randomized, controlled, open-label trial was carried out at the Cuban Institute of Gastroenterology. One hundred and twenty-two children were randomly assigned to receive either CQ (10 mg/Kg bodyweight twice a day for five days) or MTZ [15 mg/Kg bodyweight divided in three daily does for five days]. All children were asked to provide three faecal samples on days 3, 5 and 7 after treatment completion. Children were considered to be cured, if no Giardia trophozoites or cysts were found in any of the three post-treatment faecal specimens evaluated by direct wet mounts and/or after Ritchie concentration techniques. RESULTS: The frequency of cure was a little higher for CQ than for MTZ but the difference was not statistically significant. Headache was more common in patients treated with CQ as was bitter taste. Yellowish colouration of the urine was more frequent in the MTZ treated group.CONCLUSION: Chloroquine, for five days, is as efficacious as the recommended treatment with MTZ in children infected with G duodenalis(AU)

A randomized, controlled, open-label trial evaluating the efficacy and safety of chloroquine in the treatment of giardiasis in children / Estudio de etiqueta abierta, randomizado y controlado, para evaluar la eficacia y seguridad de la cloroquina en el tratamiento de la giardiasis en niños

BACKGROUND: Giardia duodenalis is among the commonest protozoan parasites in the intestinal tract of humans and may cause significant morbidity worldwide. Although there are several antigiardial agents, treatment failures have been commonly reported. OBJECTIVE: To compare the efficacy and safety of chloroquine (CQ) versus metronidazole (MTZ) in the treatment of children with confirmed G duodenalis mono-infection. METHODS: A randomized, controlled, open-label trial was carried out at the Cuban Institute of Gastroenterology. One hundred and twenty-two children were randomly assigned to receive either CQ (10 mg/Kg bodyweight twice a day for five days) or MTZ [15 mg/Kg bodyweight divided in three daily does for five days]. All children were asked to provide three faecal samples on days 3, 5 and 7 after treatment completion. Children were considered to be cured, if no Giardia trophozoites or cysts were found in any of the three post-treatment faecal specimens evaluated by direct wet mounts and/or after Ritchie concentration techniques. RESULTS: The frequency of cure was a little higher for CQ than for MTZ but the difference was not statistically significant. Headache was more common in patients treated with CQ as was bitter taste. Yellowish colouration of the urine was more frequent in the MTZ treated group. CONCLUSION: Chloroquine, for five days, is as efficacious as the recommended treatment with MTZ in children infected with G duodenalis.

ANTECEDENTES: La giardia lamblia (giardia duodenalis) se halla entre los parásitos protozoos más comunes del tracto intestinal de los seres humanos, y puede causar una morbilidad significativa a nivel mundial. Aunque existen varios agentes antigiardiales, se han reportado fracasos en el tratamiento OBJETIVO: Comparar la eficacia y seguridad de la cloroquina (CQ) con el metronidazol (MTZ) en el tratamiento de los niños con mono-infección de G duodenalis. MÉTODOS: En el Instituto Cubano de Gastroenterología, se llevó a cabo un estudio de etiqueta abierta, randomizado y controlado. Ciento veintidós niños fueron aleatoriamente designados para recibir bien CQ (10 mg/Kg peso corporal dos veces por día durante cinco días) o MTZ (15 mg/Kg peso corporal dividido en tres dosis diarias por un período de cinco días). A todos los niños se les tomaron tres pruebas fecales los días 3, 5 y 7 después de terminado el tratamiento. Los niños se daban por curados, si no había presencia de tropozoítos o quistes de giardia en ninguno de los tres especimenes fecales post-tratamiento, evaluados directamente con portaobjetos húmedos y/o después de técnicas de concentración de Ritchie. RESULTADO: La frecuencia de la cura fue un poco más alta para CQ que para MTZ, pero la diferencia no fue estadísticamente significativa. El dolor de cabeza fue más común en pacientes tratados con CQ que el sabor amargo. La coloración amarillenta de la orina fue más frecuente en el grupo tratado con MTZ. CONCLUSIÓN: La cloroquina, administrada durante cinco días, es tan eficaz como el tratamiento recomendado con MTZ en niños infectados con giardias lamblias.

Histopathological and immunohistochemical study of the hepatic lesions experimentally induced by Entamoeba dispar.

The sequence of hepatic necrotic-inflammatory events produced by Entamoeba dispar are originally described in this work. For the first time were described in details the experimental lesions produced by E. dispar, as well as the distribution of the trophozoites detected by the immunohistochemistry. Animals experimentally infected with E. dispar presented necrosis, thrombosis and chronic granulomatous inflammation. Immunoreactive products derived from trofozoites were observed close or associated with trophozoites, epithelioid cells, leucocytes and hepatocytes. Few are the articles on the literature about virulence of E. dispar, which is approximately 9 times more frequent than to E. histolytica. Variation in the virulence is, therefore expected and signalizing the need of the continuity of studies with E. dispar strains from different places in the world. Taking into account that E. dispar is a closely related species to E. histolytica, these studies could determine new elements involved with E. histolytica pathogenesis, helping us to understand better the disease.

A randomized, controlled, open-label trial evaluating the efficacy and safety of chloroquine in the treatment of giardiasis in children.

BACKGROUND: Giardia duodenalis is among the commonest protozoan parasites in the intestinal tract of humans and may cause significant morbidity worldwide. Although there are several antigiardial agents, treatment failures have been commonly reported. OBJECTIVE: To compare the efficacy and safety of chloroquine (CQ) versus metronidazole (MTZ) in the treatment of children with confirmed G duodenalis mono-infection. METHODS: A randomized, controlled, open-label trial was carried out at the Cuban Institute of Gastroenterology. One hundred and twenty-two children were randomly assigned to receive either CQ (10 mg/Kg bodyweight twice a day for five days) or MTZ [15 mg/Kg bodyweight divided in three daily does for five days]. All children were asked to provide three faecal samples on days 3, 5 and 7 after treatment completion. Children were considered to be cured, if no Giardia trophozoites or cysts were found in any of the three post-treatment faecal specimens evaluated by direct wet mounts and/or after Ritchie concentration techniques. RESULTS: The frequency of cure was a little higher for CQ than for MTZ but the difference was not statistically significant. Headache was more common in patients treated with CQ as was bitter taste. Yellowish colouration of the urine was more frequent in the MTZ treated group. CONCLUSION: Chloroquine, for five days, is as efficacious as the recommended treatment with MTZ in children infected with G duodenalis.

Mebendazole in parasitic infections other than those caused by soil-transmitted helminths.

Mebendazole, a benzimidazole carbamate compound, is currently in use for human medical practice against soil-transmitted helminthiasis (STH) and enterobiasis. However, it has been demonstrated that its spectrum of activity is broad and goes beyond those infections. Several studies provide evidence that this drug, taken at higher doses than used for STH and enterobiasis, could be sufficiently effective on some protozoa, nematodes and cestodes.

Morphometric study of the hepatic lesions experimentally induced in hamsters by Entamoeba dispar and E. histolytica.

Evolution of experimental hepatic lesions produced in hamsters with Entamoeba histolytica and E. dispar was evaluated quantitatively and qualitatively through morphometry and immunohistochemistry. Animals infected with E. dispar developed hepatic lesions quantitatively and qualitatively similar to those produced by E. histolytica on the first three days of infection. On the 6th and 8th days of infection, E. histolytica produced larger tissue damage than E. dispar. A gradual decrease was observed in the number of trophozoites along the infection. A negative correlation was observed between the reduced number of trophozoites and the larger area of necrosis in both groups, confirming the importance of trophozoites killed in the lesion genesis. Regarding the genetic similarity between E. histolytica and E. dispar, comparison strategy between lesions produced by these species may culminate in identifying virulence factors of E. histolytica.

Industrial and simulation analysis of the nitrogen trichloride decomposition process in electrolytic chlorine production.

This work presents the dynamic simulation of the thermal decomposition of nitrogen trichloride (NCl(3)) during electrolytic chlorine (Cl(2)) production, using an industrial plant as a case study. NCl(3) is an extremely unstable and explosive compound and the decomposition process has the following main problems: changeability of the reactor temperature and loss of solvent. The results of this work will be used to establish a more efficient and safe control strategy and to analyze the loss of solvent during the dynamic period. The implemented model will also be used to study the use of a new solvent, considering that currently used solvent will be prohibited from commercial use in 2010. The process was simulated by using the commercial simulator Aspen and the simulations were validated with plant data. From the results of the simulation it can be concluded that the rate of decomposition depends strongly on the temperature of the reactor, which has a stronger relationship to the liquid Cl(2) (reflux) and gaseous Cl(2) flow rates which feed the system. The results also showed that the loss of solvent changes strongly during the dynamic period.

Structure of a thiolate-bridged polymeric copper(I) compound, catena-(2,9-dimethyl-1,10-phenanthroline)-mu-(thiophenolato)-copper(I).

[Cu(C6H5S)(C14H12N2)], Mr = 380.97, monoclinic, P2(1), a = 10.047 (1), b = 15.797 (2), c = 10.581 (1) A, beta = 90.78 (1) degrees, V = 1679.2 A3, Z = 4, Dm (CCl4/C5H12) = 1.50, D chi = 1.51 g cm-3, lambda(Mo K alpha) = 0.7107 A, mu = 14.2 cm-1, F(000) = 784, T = 293 (1) K, R = 0.026, wR = 0.026 for 2709 observed reflections. The title compound, [Cu(Me2-phen)(C6H5S)]n, exists as chains of [Cu(Me1phen)]+ units linked by thiophenolate S atoms. Large bridging angles at thiolate S atoms [Cu(1)--S--Cu(2)(av.) = 134 (1) degrees] preclude any Cu--Cu bonding [Cu ... Cu = 4.246 (1), 4.284 (1) A] along the chain. The CuI atoms exhibit highly distorted tetrahedral coordination, with the largest deviations from tetrahedral stereochemistry involving the N--Cu--N and S--Cu--S angles [N--Cu--N(av.) = 78.0(2), S--Cu--S(av.) = 126 (3) degrees].

Removal of the tightly bound zinc from Escherichia coli trypsin-modified methionyl-tRNA synthetase.

The study of the behaviour of Escherichia coli methionyl-tRNA synthetase with chelating agents has shown that only 1,10-phenanthroline has an inhibitory effect on the tRNAMet aminoacylation activity. Under identical buffer conditions the isotopic [32P]PPi-ATP exchange activity is insensitive. Dialysis of the enzyme against 1,10-phenanthroline causes a slow loss of zinc from the enzyme which is paralleled by an irreversible loss of both the aminoacylation and isotopic exchange activities. The loss of zinc becomes faster upon the addition of small amounts of guanidine hydrochloride to the dialysis buffer containing phenanthroline, presumably by partially unfolding the protein. Studies of the reversible denaturation of the enzyme by 5 M guanidine hydrochloride shows that the inclusion of EDTA produces an enzyme species that has lost both zinc and activity. The inactive apoenzyme prepared in guanidine and EDTA can regain activity by dilution in a zinc-containing buffer.

Kinetics of formation and dissociation of metallocarboxypeptidases.

The rates of formation of a number of metallocarboxypeptidases from metal ions and bovine apocarboxypeptidase A (CPA) have been measured directly and by a competitive method. Rates were determined with pH = 6-8 by utilising the pH change attending metal-ion incorporation, employing indicator and stopped-flow. Second-order rate constants Kf, M-1 s-1 at 25 degrees C, I = 1 M NaCl, pH = 7, Tris = 25 micrometer) were 1.7 X 10(5) (Mn2+), 3 X 10(4) (Co2+), 5 X 10(3) (Ni2+), 7 X 10(5) Zn2+), and 9 X 10(5) (Cd2+). Relative incorporation rate constants were determined at 25 degrees, pH = 7.0, Tris = 0.1 M, by competing two metal ions for a deficiency of apoprotein and analyzing the products by differential enzyme activity. Agreement between the two methods was reasonable. Rate constants for dissociation of CoCPA, NiCPA, and ZnCPA were measured by loss of enzyme activity on addition of the metal ion scavenger EDTA. Values of kd at 25 degrees, I = 1.0 M NaCl, pH = 7.0 were 8 X 10(-3), 3 X 10(-5), and 4 X 10(-4) s(-1), respectively. Values of K obtained kinetically (kf/kd) were in good agreement with those determined by activity measurements of equilibrated solutions. Results are compared with those of bovine apocarbonic anhydrase, where generally significantly slower rates are encountered.