Molecular characterization and antimicrobial resistance profiles of Salmonella Heidelberg isolates from poultry.

In the last 10 years, Salmonella Heidelberg has been extensively isolated from poultry in several countries. In this context, molecular characterization is essential to understand whether the strains have entered the farms from a single or several sources. Thus, the aim of this study was to determine the genetic relationship and antimicrobial susceptibility of S. Heidelberg strains isolated between 2011 and 2012 from broiler farms belonging to three integrated poultry companies located in Argentina. The genetic relatedness of the S. Heidelberg isolates was determined by pulsed-field gel electrophoresis (PFGE), and resistance to 21 antimicrobials was determined by the disc diffusion method. The isolates were assigned to four PFGE patterns. Most of the strains showed 100% similarity and belonged to the same integrated poultry company. This PFGE pattern was also prevalent in S. Heidelberg strains isolated from humans in several provinces of Argentina, which suggests an epidemiological association between human and poultry strains. All the isolates were classified as multidrug-resistant (MDR), and no clear relationship was observed between PFGE and resistance patterns. S. Heidelberg strains may circulate among farms from the same integrated company due to common sources of contamination. To guarantee the safety of the poultry product for the consumers, holistic approaches including surveillance of Salmonella throughout the production chain together with control measures are crucial.

Immunization of pregnant cows with Shiga toxin-2 induces high levels of specific colostral antibodies and lactoferrin able to neutralize E. coli O157:H7 pathogenicity.

E. coli O157:H7 is a foodborne pathogen responsible for bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). The objective of the present work was to evaluate the ability of colostral IgG obtained from Stx2-immunized cows to prevent against E. coli O157:H7 infection and Stx2 cytotoxicity. Hyperimmune colostrum (HC) was obtained from cows intramuscularly immunized with inactivated Stx2 or vehicle for controls. Colostral IgG was purified by affinity chromatography. Specific IgG antibodies against Stx2 and bovine lactoferrin (bLF) levels in HC and the corresponding IgG (HC-IgG/bLF) were determined by ELISA. The protective effects of HC-IgG/bLF against Stx2 cytotoxicity and adhesion of E. coli O157:H7 and its Stx2-negative mutant were analyzed in HCT-8 cells. HC-IgG/bLF prevention against E. coli O157:H7 was studied in human colon and rat colon loops. Protection against a lethal dose of E. coli O157:H7 was evaluated in a weaned mice model. HC-IgG/bLF showed high anti-Stx2 titers and high bLF levels that were able to neutralize the cytotoxic effects of Stx2 in vitro and in vivo. Furthermore, HC-IgG/bLF avoided the inhibition of water absorption induced by E. coli O157:H7 in human colon and also the pathogenicity of E. coli O157:H7 and E. coli O157:H7Δstx2 in rat colon loops. Finally, HC-IgG/bLF prevented in a 100% the lethality caused by E. coli O157:H7 in a weaned mice model. Our study suggests that HC-IgG/bLF have protective effects against E. coli O157:H7 infection. These beneficial effects may be due to specific anti-Stx2 neutralizing antibodies in combination with high bLF levels. These results allow us to consider HC-IgG/bLF as a nutraceutical tool which could be used in combination with balanced supportive diets to prevent HUS. However further studies are required before recommendations can be made for therapeutic and clinical applications.

Immune Response in Calves Vaccinated with Type Three Secretion System Antigens and Shiga Toxin 2B Subunit of Escherichia coli O157:H7.

Ruminants are the primary reservoir of Shiga-toxin producing Escherichia coli (STEC) O157:H7 and the main source of infection for humans. The aim of this study was to assess the immunogenic properties of a candidate vaccine consisting on the recombinant proteins of E. coli O157:H7 IntiminC280, the carboxy-terminal fraction of Intimin γ, EspB and the fusion protein between the B subunit of Stx2 and Brucella Lumazine Synthase (BLS)(BLS-Stx2B), in Holstein Fresian calves.To accomplish this goal we vaccinated calves with two doses of different vaccine formulations: 2 antigens (IntiminC280, EspB), 3 antigens (IntiminC280, EspB, BLS-Stx2B), BLS-Stx2B alone and a control non-vaccinated group. All antigens were expressed as recombinant proteins in E. coli. Specific IgG titres increased in vaccinated calves and the inclusion of BLS-Stx2B in the formulation seems to have a stimulatory effect on the humoral response to IntiminC280 and EspB after the booster. The neutralizing activity of antibodies against these two antigens was assessed in Red Blood Cell lysis assays and adherence to Hep-2 cells as a correlate of T3SS activity. Both sera from animals vaccinated with 2 or 3 antigens inhibited both virulence properties. Serological response to Stx2 was observed in animals vaccinated only with BLS-Stx2B and with 3 antigens and neutralization of Stx2 cytotoxicity was also observed in both groups. In conclusion, immunization of calves with BLS-Stx2B, IntiminC280 and EspB elicited a potent humoral response able to neutralize Shiga toxin 2 cytotoxity and the T3SS virulence properties in vitro. These results suggest that this formulation is a good candidate vaccine to reduce STEC shedding in cattle and needs to be further assessed in vivo.

Modified PAS stain: a new diagnostic method for onychomycosis / Examen directo teñido con PAS: un nuevo método diagnóstico de la onicomicosis

Background. Onychomycosis is the most common nail disease and represents around 50% of nail disorders. Accurate diagnosis with adequate evidence is ideal before starting any treatment. Current diagnostic methods offer low specificity and sensitivity. Aims. To create a new method for the diagnosis of onychomycosis, and to compare its sensitivity and specificity with the existing methods. Methods. One hundred and ninety-two samples with clinical suspicion of onychomycosis were included and underwent modified PAS stain (M-PAS), KOH/chlorazol black (KOH/CB) and culture testing. Sensitivity, specificity, positive and negative predictive values were calculated. Results. In 152 out of 192 samples (79.2%) fungi structures were found in at least one of the three tests performed, and the patients were diagnosed with onychomycosis; 40 samples out of 192 (20.8%) were negative. Using M-PAS, filaments and/or spores were seen in 143 samples from the 152 positive (94%); 39 of them were negative to KOH/CB and positive to M-PAS (25.6%). With KOH/CB, filaments and/or spores were seen in 113 cases from the 152 positive samples (73.8% of the onychomycosis cases). Thirty-five cultures were positive, of which 77% were identified as Trichophyton rubrum; 117 onychomycosis cases were diagnosed despite the negative culture (76.9%). M-PAS showed 92.5% sensitivity and 55.55% specificity, a 67.5% positive predictive value and a 81.6% negative productive value. Conclusions. This procedure, a combination of the existing methods to diagnose onychomycosis, KOH/CB together with a nail clipping biopsy, proved to have high sensitivity, as well as being rapid, easy, inexpensive and readily available in most hospital settings. M-PAS allowed us to diagnose 39 cases (25.6% of the cases of onychomycosis) that were false negative using only KOH/CB and culture (AU)

Antecedentes. La onicomicosis es la enfermedad más común de las uñas y representa un 50% del total de las enfermedades que afectan a esta parte del cuerpo. Antes de iniciar un tratamiento, es muy recomendable contar con un diagnóstico preciso y pruebas suficientes. En la actualidad, los métodos diagnósticos ofrecen una sensibilidad y especificidad bajas. Objetivos. Crear un nuevo método de diagnóstico de la onicomicosis y comparar su sensibilidad y especificidad con los métodos diagnósticos existentes. Métodos. Se recogieron ciento noventa y dos muestras con sospecha clínica de onicomicosis en las que se aplicaron las pruebas de examen directo con KOH/Negro de clorazol (KOH/CB), cultivo y examen directo teñido con PAS (M-PAS). Se calcularon la sensibilidad, la especificidad, y los valores predictivos positivo y negativo. Resultados. En 152 de las 192 muestras (79,2%) se hallaron estructuras micóticas en una de las tres pruebas realizadas como mínimo, y se diagnosticó onicomicosis en dichos pacientes; 40 de las 192 muestras (20,8%) dieron resultados negativos. Mediante M-PAS, se observaron filamentos o esporas en 143 de las 152 muestras (94%); 39 de ellas resultaron negativas con KOH/CB y positivas con M-PAS (25,6%). En el caso de KOH/CB, se observaron filamentos o esporas en 113 de las 152 muestras, (73,8% de los casos de onicomicosis). Treinta y cinco cultivos dieron resultados positivos, conel 77% de los aislamientos obtenidos identificados como Trichophyton rubrum; se diagnosticaron 117 casos de onicomicosis a pesar de los resultados negativos en el cultivo (76,9%). La sensibilidad de M-PAS fue del 92,5%, la especificidad del 55,55%, y los valores predictivos positivo y negativo de 67,5% y 81,6%, respectivamente. Conclusiones. Este procedimiento, una fusión de métodos ya existentes para el diagnóstico de la onicomicosis, que aplica KOH/CB junto con una biopsia de fragmentos de uña, mostró una gran sensibilidad. Es además un método rápido, fácil, económico y disponible en la mayoría de los ámbitos hospitalarios. M-PAS permitió diagnosticar 39 casos (25,6% de los pacientes con onicomicosis) con resultados falsos negativos al utilizar únicamente KOH/CB y cultivo (AU)

Modified PAS stain: A new diagnostic method for onychomycosis.

BACKGROUND: Onychomycosis is the most common nail disease and represents around 50% of nail disorders. Accurate diagnosis with adequate evidence is ideal before starting any treatment. Current diagnostic methods offer low specificity and sensitivity. AIMS: To create a new method for the diagnosis of onychomycosis, and to compare its sensitivity and specificity with the existing methods. METHODS: One hundred and ninety-two samples with clinical suspicion of onychomycosis were included and underwent modified PAS stain (M-PAS), KOH/chlorazol black (KOH/CB) and culture testing. Sensitivity, specificity, positive and negative predictive values were calculated. RESULTS: In 152 out of 192 samples (79.2%) fungi structures were found in at least one of the three tests performed, and the patients were diagnosed with onychomycosis; 40 samples out of 192 (20.8%) were negative. Using M-PAS, filaments and/or spores were seen in 143 samples from the 152 positive (94%); 39 of them were negative to KOH/CB and positive to M-PAS (25.6%). With KOH/CB, filaments and/or spores were seen in 113 cases from the 152 positive samples (73.8% of the onychomycosis cases). Thirty-five cultures were positive, of which 77% were identified as Trichophyton rubrum; 117 onychomycosis cases were diagnosed despite the negative culture (76.9%). M-PAS showed 92.5% sensitivity and 55.55% specificity, a 67.5% positive predictive value and a 81.6% negative productive value. CONCLUSIONS: This procedure, a combination of the existing methods to diagnose onychomycosis, KOH/CB together with a nail clipping biopsy, proved to have high sensitivity, as well as being rapid, easy, inexpensive and readily available in most hospital settings. M-PAS allowed us to diagnose 39 cases (25.6% of the cases of onychomycosis) that were false negative using only KOH/CB and culture.

Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 from Cattle in Argentina have Hypervirulent-Like Phenotypes.

The hemolytic uremic syndrome (HUS) whose main causative agent is enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a disease that mainly affects children under 5 years of age. Argentina is the country with the highest incidence of HUS in the world. Cattle are a major reservoir and source of infection with E. coli O157:H7. To date, the epidemiological factors that contribute to its prevalence are poorly understood. Single nucleotide polymorphism (SNP) typing has helped to define nine E. coli O157:H7 clades and the clade 8 strains were associated with most of the cases of severe disease. In this study, eight randomly selected isolates of EHEC O157:H7 from cattle in Argentina were studied as well as two human isolates. Four of them were classified as clade 8 through the screening for 23 SNPs; the two human isolates grouped in this clade as well, while two strains were closely related to strains representing clade 6. To assess the pathogenicity of these strains, we assayed correlates of virulence. Shiga toxin production was determined by an ELISA kit. Four strains were high producers and one of these strains that belonged to a novel genotype showed high verocytotoxic activity in cultured cells. Also, these clade 8 and 6 strains showed high RBC lysis and adherence to epithelial cells. One of the clade 6 strains showed stronger inhibition of normal water absorption than E. coli O157:H7 EDL933 in human colonic explants. In addition, two of the strains showing high levels of Stx2 production and RBC lysis activity were associated with lethality and uremia in a mouse model. Consequently, circulation of such strains in cattle may partially contribute to the high incidence of HUS in Argentina.

Candida species isolation in peristomal skin in patients with abdominal stomas and correlation to clinical signs: a descriptive pilot study.

The reported prevalence of candidiasis in peristomal skin varies greatly. Very few studies exist that correlate the clinical findings around the peristomal skin to the mycology. In this study, the authors report on Candida species prevalence, clinical correlation, and mycology.

Feohifomicosis subcutánea producida por Curvularia lunata en un paciente receptor de un trasplante renal / Subcutaneous phaeohyphomycosis due to Curvularia lunata in a renal transplant patient

Fundamento. La feohifomicosis se define como una infección causada por hongos dematiáceos (melanizados). Predomina en climas tropicales y en la actualidad es bien conocido que se manifiesta en forma superficial, cutánea, subcutánea y sistémica del sistema nervioso central o pulmonar diseminada. Curvularia es uno de los numerosos géneros que pueden causar esta infección. En las formas subcutáneas es más frecuente aislar Phialophora, Alternaria o Exophiala. Caso clínico. Un hombre de 25 años de edad, receptor de un trasplante renal, se presentó con una úlcera en la pierna izquierda. Mediante examen micológico y los hallazgos histopatológicos se estableció el diagnóstico de feohifomicosis subcutánea producida por Curvularia lunata. Se trató satisfactoriamente con itraconazol sistémico y la resección quirúrgica de la úlcera. Conclusión. A pesar de que, en las últimas décadas, se ha incrementado la incidencia de feohifomicosis, en particular en pacientes inmunosuprimidos, el número de casos no permite que se emprendan ensayos controlados terapéuticos. Por esta razón, consideramos que es importante comunicar los casos clínicos individuales y revisar los estudios publicados para aumentar los conocimientos sobre esta enfermedad, su presentación clínica y la respuesta al tratamiento(AU)

Background. Phaeohyphomycosis is defined as an infection caused by melanized fungi. It predominates in tropical climate and is currently classified as superficial, allergic, central nervous system or lung infections, and disseminated. Curvularia is one of the many genres which can cause this disease. Phialophora, Alternaria and Exophiala are more commonly isolated from subcutaneous lesions. Case report. A 25-year-old male, renal transplant recipient presents with an ulcer on his left leg. Subcutaneous phaeohyphomycosis due to Curvularia lunata was diagnosed based on mycological examination and histopathological findings. He was successfully treated with systemic itraconazole and surgical resection. Conclusion. The incidence of phaeohyphomycosis has increased in the last decades, especially in immunosuppressed individuals; nevertheless the number of cases does not allow for therapeutic controlled trials to be performed. Hence, we consider that it is important to communicate individual cases and reviews of the literature, to increase awareness of the disease, its clinical presentation and response to treatment(AU)

Effect of coiled-coil peptides on the function of the type III secretion system-dependent activity of enterohemorragic Escherichia coli O157:H7 and Citrobacter rodentium.

Many animal and human pathogenic Gram-negative bacteria such as Salmonella, Yersinia, enterohemorrhagic Escherichia coli (EHEC), and enteropathogenic Escherichia coli (EPEC) possess a type III secretion system (TTSS) that is used to deliver virulence proteins directly into the host cell. Recent evidence has suggested that CoilA and CoilB, two synthetic peptides corresponding to coiled-coil domains of the translocator protein EspA, are effective in inhibiting the action of TTSS from EPEC. In the current study, the action of these coiled-coil peptides on the TTSS of EHEC O157:H7 and Citrobacter rodentium was examined. CoilA and CoilB showed to be effective in reducing the red blood cell lysis mediated by EHEC O157:H7 and the in vitro secretion of translocator proteins EspB and EspD by EHEC O157:H7 and EspD by C. rodentium. Treatment of mice with CoilA and CoilB peptides prevented colon damage when the animals were inoculated with C. rodentium. Colon samples of the non-treated group showed areas with loss of superficial epithelium, damaged cells, and endoluminal mononuclear inflammatory infiltrate, consistent with histological lesions induced by C. rodentium, whereas mice treated with the synthetic peptides displayed normal surface epithelium showing a similar structure as the uninfected control group. These encouraging results prompt us to test coiled-coil peptides as treatment or vaccines in other models of bacterial infections in future work.

Subcutaneous phaeohyphomycosis due to Curvularia lunata in a renal transplant patient.

BACKGROUND: Phaeohyphomycosis is defined as an infection caused by melanized fungi. It predominates in tropical climate and is currently classified as superficial, allergic, central nervous system or lung infections, and disseminated. Curvularia is one of the many genres which can cause this disease. Phialophora, Alternaria and Exophiala are more commonly isolated from subcutaneous lesions. CASE REPORT: A 25-year-old male, renal transplant recipient presents with an ulcer on his left leg. Subcutaneous phaeohyphomycosis due to Curvularia lunata was diagnosed based on mycological examination and histopathological findings. He was successfully treated with systemic itraconazole and surgical resection. CONCLUSION: The incidence of phaeohyphomycosis has increased in the last decades, especially in immunosuppressed individuals; nevertheless the number of cases does not allow for therapeutic controlled trials to be performed. Hence, we consider that it is important to communicate individual cases and reviews of the literature, to increase awareness of the disease, its clinical presentation and response to treatment.

Sporotrichosis.

Sporotrichosis is the most common subcutaneous mycosis. It is usually acquired by traumatic inoculation, and it is caused by one of the species of the Sporothrix schenckii complex. More than 6 species, such as S schenckii sensu stricto, Sporothrix brasiliensis, Sporothrix globosa, Sporothrix mexicana, and Sporothrix albicans, have been identified by molecular techniques. The most common presentation is cutaneous disease, which is classified into fixed and lymphocutaneous forms. Osteoarticular, pulmonary, mucosal, disseminated, and systemic infections are less common and usually occur in immunosuppressed individuals. The diagnosis is suggested by biopsy specimen and confirmed by tissue culture. Itraconazole is considered the treatment of choice, although in some undeveloped countries potassium iodide is still used, owing to its safety and low cost. For systemic or disseminated cases, amphotericin B is the treatment of choice.

Reduced faecal shedding of Escherichia coli O157:H7 in cattle following systemic vaccination with γ-intimin C280 and EspB proteins.

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is the most prevalent EHEC serotype that has been recovered from patients with haemolytic uremic syndrome (HUS) worldwide. Vaccination of cattle, the main reservoir of EHEC O157:H7, could be a logical strategy to fight infection in humans. This study evaluated a vaccine based on the carboxyl-terminal fragment of 280 amino acids of γ-intimin (γ-intimin C280) and EspB, two key colonization factors of E. coli O157:H7. Intramuscular immunization elicited significantly high levels of serum IgG antibodies against both proteins. Antigen-specific IgA and IgG were also induced in saliva, but only the IgA response was significant. Following experimental challenge with E. coli O157:H7, a significant reduction in bacterial shedding was observed in vaccinated calves, compared to control group. These promising results suggest that systemic immunization of cattle with intimin and EspB could be a feasible strategy to reduce EHEC O157:H7 faecal shedding in cattle.

Necrotic enteritis in young calves.

Non-enterotoxin (CPE)-producing Clostridium perfringens type A has been associated with enteritis in calves. Recent evidence has suggested that a novel toxin, named beta2 (CPB2), is implicated in the pathogenesis of this disease, although there is little evidence supporting this. In the current study, the role of C. perfringens type A in an outbreak of enteritis in calves was studied. Two 20-day-old dairy calves exhibiting apathy and reluctance to eat, with paresis of the anterior limbs, were euthanized for postmortem examination. Gross and histological changes compatible with acute enteritis, rumenitis, meningitis, and pneumonia were seen in both calves. Clostridium perfringens type A non-CPE, non-CPB2 was isolated from the abomasum and the small intestine. Escherichia coli ONTH8 (with cdtBIII and f17 virulence genes detected by polymerase chain reaction) was also isolated from the brain, abomasum, and intestine from both calves. All the samples were negative for Salmonella spp. When the C. perfringens strain was inoculated into bovine ligated small and large intestinal loops, cell detachment, erosion, and hemorrhage of the lamina propria were observed, predominantly in the small intestine. The results suggest that non-CPE, non-CPB2 C. perfringens type A is able to induce pathologic changes in the intestine of calves, probably enhanced by other pathogens, such as some pathogenic E. coli strains.

Successful treatment of Nocardia actinomycetoma with meropenem and amikacin combination therapy.

BACKGROUND: Actinomycetomas are chronic, granulomatous, subcutaneous infections caused by the traumatic inoculation of actinomycetes bacteria into the skin which produces nodular lesions with draining sinuses and discharging grains. Actinomycetomas can cause profound disability, and despite long-term chemotherapy, treatment failure is common. AIMS: We investigated the efficacy of a novel drug regimen for the treatment of a severe case of Nocardia actinomycetoma of the leg. MATERIAL AND METHODS: A 31-year-old man was treated with an initial three-week parenteral course of meropenem and amikacin combination therapy followed by long term oral sulphonamides. RESULTS: Treatment was well-tolerated with no adverse effects, and there was complete clinical and microbiological cure with no recurrence. CONCLUSION: Meropenem and amikacin combination therapy represents an important addition to the currently available treatments for actinomycetomas.

Upper alimentary tract papillomas in calves related to papillomavirus infection.

This study reports 3 cases of spontaneous papillomavirus infection in 1-week-old calves. Thickening of the omasum and abomasum wall, with acute inflammation, necrosis, ulceration, and neoplastic changes were seen in 1 calf. In the other 2, small papillomas were observed in the omasal mucosa, exhibiting proliferation of the parakeratinized epithelium. Papillomavirus antigens were detected by immunohistochemistry and virus-like particles were seen through electron microscopy.

Effect of tannins on the in vitro growth of Clostridium perfringens.

Vegetable tannins are water-soluble polyphenolic compounds of varying molecular weights that occur abundantly in nature. The diet of many free-ranging wild animals contains significant amounts of tannins. Also, commercial tannins are used in animal industry as food additives to improve animal performance. In order to further determine the capacity of tannins to inhibit the development of intestinal diseases produced by Clostridium pefringens, we evaluated here the effect of tannins from quebracho, chestnut or combinations of both on C. perfringens and their toxins. The C. perfringens (types A, B, C, D and E) growth obtained from the intestine of healthy and diseased animals was reduced in a dose-dependent manner in the presence of quebracho tannins, chestnut tannins, combinations of both or a commercial formula based in these tannins. Although the minimal inhibitory concentration of both tannins varied between isolates, no statistically significant differences were observed between isolates from healthy or sick animals. Comparative analysis showed that the concentrations of quebracho tannin inhibiting the growth of C. perfringens were higher than chestnut tannin. In fact, antibacterial effect of quebracho tannin was increased up to 20 times with the addition of 25% of chestnut tannin and 85 times with 75% of chestnut tannin. Antibacterial activity of the commercial product was up to ~50 times higher than quebracho tannin alone. Quebracho tannin showed partial bactericidal activity, whereas chestnut tannin activity was stronger. Both tannins were able to reduce the alpha toxin lecithinase activity and epsilon toxin cytotoxicity in MDCK cells. These results suggest that tannin-supplemented diet could be useful to prevent some clostridial diseases.

Designed coiled-coil peptides inhibit the type three secretion system of enteropathogenic Escherichia coli.

BACKGROUND: Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are two categories of E. coli strains associated with human disease. A major virulence factor of both pathotypes is the expression of a type three secretion system (TTSS), responsible for their ability to adhere to gut mucosa causing a characteristic attaching and effacing lesion (A/E). The TTSS translocates effector proteins directly into the host cell that subvert mammalian cell biochemistry. METHODS/PRINCIPAL FINDINGS: We examined synthetic peptides designed to inhibit the TTSS. CoilA and CoilB peptides, both representing coiled-coil regions of the translocator protein EspA, and CoilD peptide, corresponding to a coiled-coil region of the needle protein EscF, were effective in inhibiting the TTSS dependent hemolysis of red blood cells by the EPEC E2348/69 strain. CoilA and CoilB peptides also reduced the formation of actin pedestals by the same strain in HEp-2 cells and impaired the TTSS-mediated protein translocation into the epithelial cell. Interestingly, CoilA and CoilB were able to block EspA assembly, destabilizing the TTSS and thereby Tir translocation. This blockage of EspA polymerization by CoilA or CoilB peptides, also inhibited the correct delivery of EspB and EspD as detected by immunoblotting. Interestingly, electron microscopy of bacteria incubated with the CoilA peptide showed a reduction of the length of EspA filaments. CONCLUSIONS: Our data indicate that coiled-coil peptides can prevent the assembly and thus the functionality of the TTSS apparatus and suggest that these peptides could provide an attractive tool to block EPEC and EHEC pathogenesis.

Efficacy of imipenem therapy for Nocardia actinomycetomas refractory to sulfonamides.

BACKGROUND: Actinomycetomas are chronic, granulomatous, subcutaneous infections caused by actinomycetes bacteria. Despite prolonged high-dose and combination antibiotic therapies, some cases remain resistant with risks of bone and visceral involvement. OBJECTIVES: We sought to evaluate the efficacy and safety of imipenem monotherapy, and in combination with amikacin for the treatment of severe and refractory disease, and to identify the disease characteristics that might predict therapy failure with first-line sulfonamides. METHODS: A retrospective study was performed of all microbiologically confirmed cases of actinomycetomas treated since 1995 at a tertiary center for mycology. Eleven patients (Nocardia, n = 10) were treated with sulfonamide combinations (trimethoprim/sulfamethoxazole and dapsone). Eight patients (Nocardia, n = 7) refractory to previous therapies including sulfonamides received a 3-week course of either parenteral imipenem monotherapy (1.5 g daily, n = 3) or combination therapy with amikacin (1 g daily, n = 5), which was repeated at 6-month intervals. RESULTS: Eleven patients with limited disease and mean disease duration of 1.7 years responded successfully to sulfonamides after a mean treatment period of 15 months (range 6-48 months). Patients receiving imipenem had mean disease duration of 10 years, with visceral and bone involvement in 4 patients. Imipenem treatment was well tolerated, and 4 patients achieved clinical and microbiological cure after one to two courses of treatment, the others demonstrating greater than 75% clinical improvement and negative culture results. LIMITATIONS: Patient cohorts in this study were small because strict criteria for inclusion included species identification and adequate follow-up periods. The efficacy data for imipenem +/- amikacin therapy cannot be extrapolated to all Nocardia mycetomas, as the cohort treated in this study had particularly refractory infection. CONCLUSIONS: Sulfonamides are effective for limited disease of relatively short duration. Imipenem monotherapy or in combination with amikacin is well tolerated and demonstrates efficacy in severe disease refractory to sulfonamides.