Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular epidemiology of virulent Rhodococcus equi from foals in Brazil: virulence plasmids of 85-kb type I, 87-kb type I, and a new variant, 87-kb type III

We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 41 foals (19 sporadic and seven endemic cases) in Brazil between 1991 and 2003. of the 41 virulent isolates, six contained an 85-kb type I plasmid, 33 contained an 87-kb type I plasmid, both of which have been found in isolates from the Americas, and the remaining two contained a new variant, which did not display the EcoRI, EcoT221 and BamHI digestion patterns of the 11 representative plasmids already reported (85-kb types I-IV; 87-kb types I and II; 90-kb types I-V). We tentatively designated the new variant as the '87-kb type III' plasmid, because its BamHI digestion pattern is similar to that of the 87-kb type I plasmid. This is the first report of the molecular epidemiology surveillance of virulent R. equi in clinical isolates from Brazilian foals. (C) 2004 Elsevier Ltd. All rights reserved.

Candida species: Current epidemiology, pathogenicity, biofilm formation, natural antifungal products and new therapeutic options

The incidence of fungal infections has increased significantly, so contributing to morbidity and mortality. This is caused by an increase in antimicrobial resistance and the restricted number of antifungal drugs, which retain many side effects. Candida species are major human fungal pathogens that cause both mucosal and deep tissue infections. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth. Biofilms are biological communities with a high degree of organization, in which micro-organisms form structured, coordinated and functional communities. These biological communities are embedded in a self-created extracellular matrix. Biofilm production is also associated with a high level of antimicrobial resistance of the associated organisms. The ability of Candida species to form drugresistant biofilms is an important factor in their contribution to human disease. The study of plants as an alternative to other forms of drug discovery has attracted great attention because, according to the World Health Organization, these would be the best sources for obtaining a wide variety of drugs and could benefit a large population. Furthermore, silver nanoparticles, antibodies and photodynamic inactivation have also been used with good results. This article presents a brief review of the literature regarding the epidemiology of Candida species, as well as their pathogenicity and ability to form biofilms, the antifungal activity of natural products and other therapeutic options. © 2013 SGM.

Cryptococcosis: epidemiology, fungal resistance, and new alternatives for treatment

Cryptococcosis is an important systemic mycosis and the third most prevalent disease in human immunodeficiency virus (HIV)-positive individuals. The incidence of cryptococcosis is high among the 25 million people with HIV/acquired immunodeficiency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. In Cryptococcus neoformans, resistance to azoles may be associated with alterations in the target enzyme encoded by the gene ERG11, lanosterol 14α-demethylase. These alterations are obtained through mutations, or by overexpressing the gene encoding. In addition, C. gattii and C. neoformans present a heteroresistance phenotype, which may be related to increased virulence. Other species beyond C. neoformans and C. gattii, such as C. laurentii, have been diagnosed mainly in patients with immunosuppression. Infections of C. albidus have been isolated in cats and marine mammals. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth, which is also related with increased resistance to antifungal agents. Therefore, there is a great need to search for alternative antifungal agents for these fungi. The search for new molecules is currently occurring from nanoparticle drugs of plant peptide origin. This article presents a brief review of the literature regarding the epidemiology of cryptococcosis, as well as fungal resistance and new alternatives for treatment. © 2013 Springer-Verlag Berlin Heidelberg.

Epidemiology of human immunodeficiency virus-visceral leishmaniasis-co-infection

In Brazil, the rates of mother-to-child-transmission (MTCT) of human immunodeficiency virus (HIV) decreased from 20% to 1-2% in some regions. However, the country contains 90% of individuals infected with visceral leishmaniasis (VL) in Latin America, and the west region of São Paulo state faces an alarming expansion of the disease. We describe the epidemiological aspects of the expanding infection of VL and a case report of an HIV-VL-co-infected child from the west region of São Paulo state. The patient was an AIDS-C3 with low levels of CD4, high viral load, severe diarrhea, oral and perineal candidiasis, severe thrombocytopenia, and protein-caloric malnourishment. She evolved with sepsis, renal and cardiac failure. An rK rapid diagnosis test, indirect fluorescent antibody test (IFAT), and bone marrow aspirate were performed for VL. Her symptoms improved significantly after liposomal amphotericin B administration. From the 45 municipalities that compose the Regional Health Department of Presidente Prudente, Lutzomyia longipalpis vectors were found in 58% of them. VL infected dogs were found in 33% of those municipalities, infected dogs and humans were found in 29%, 20% are starting and 33% of the municipalities are preparing VL investigation. It is likely, in this patient, that VL advanced the clinical progression of the HIV disease and the development of AIDS severity. Supported by favorable conditions, the region becomes a new frontier of VL in Brazil. © 2013.

Retrieval of Trichostrongylus colubriformis infective larvae from grass contaminated in winter and in spring

The survival of infective larvae (L3) of Trichostrongylus colubriformis was evaluated on Brachiaria, Coast-cross and Aruana forage grasses. Feces of sheep parasitized exclusively by T. colubriformis were deposited in winter and spring on experimental plots whose grasses were cut at two heights: 5 cm and 30 cm. One, two, four, eight, 12 and 16 weeks after depositing the feces, fecal and forage samples were collected for the retrieval and quantification of L3. Retrieval of L3 from feces and forage was negligible in winter due to the dry weather, although a few larvae were retrieved in the last larval collections. However, L3 retrieval from fecal samples was greater in spring, especially two weeks after feces were deposited on 30 cm high grasses. At this time, the L3 retrieval rate from the three forage grasses differed significantly (P < 0.05), with Aruana grass showing the highest average L3 retrieval rate, followed by Coast-cross and Brachiaria. In conclusion, the winter drought proved very unfavorable for the presence of L3 in the environment, and the microclimate of Aruana pastureland was generally the most favorable for the retrieval of infective larvae.

Molecular epidemiology of extended-spectrum-beta-lactamase-producing Klebsiella pneumoniae over a 10 year period in Calgary, Canada

A study was designed to investigate the molecular epidemiology of extended-spectrum -lactamase (ESBL)-producing Klebsiella pneumoniae isolated in a centralized region over a 10 year period (200009). Molecular characterization was done using isoelectric focusing, PCR and sequencing for bla(CTX-M), bla(TEM) and bla(SHV) genes and plasmid-mediated quinolone resistance determinants. Genetic relatedness was determined with PFGE using XbaI and multilocus sequencing typing. A total of 89 patients with incident infections were identified; the majority presented with hospital-onset urinary tract infections. The absolute number of ESBL-producing isolates remained very low until 2003, increased slightly in 2004, remained stable until 2008 and then in 2009 there was an abrupt increase in the numbers of ESBL producers identified. The majority of K. pneumoniae produced CTX-M-14 and -15, and have replaced SHV-12-producing isolates since 2005. We identified four different major sequence types (STs) among 32 of isolates (i.e. ST17, ST20, and the new ST573 and ST575) and provided insight into their clinical and molecular characteristics. The ST isolates were more likely to produce community-onset infections, were associated with bla(CTX-M) and emerged during the latter part of the study period. ST17 produced CTX-M-15 and SHV-12, and was more likely to be positive for qnrB; ST20 produced CTX-M-14 and was positive for qnrS. The multiresistant ST575 that produced CTX-M-15 appeared in 2009. Our study highlights the importance of molecular epidemiology in providing insight into the emergence, characteristics and distribution of STs among ESBL-producing K. pneumoniae.

Genetic features and molecular epidemiology of Enterococcus faecium isolated in two university hospitals in Brazil

The global emergence of vancomycin-resistant Enterococcus faecium (VREfm) has been characterized by a clonal spread of strains belonging to clonal complex 17 (CC17). Genetic features and clonal relationships of 53 VREfm isolated from patients in 2 hospitals in Ribeirao Preto, Sao Paulo, Brazil, during 2005-2010 were determined as a contribution to the Brazilian evolutionary history of these nosocomial pathogens. All isolates were daptomycin susceptible, vancomycin-resistant, and had the vanA gene. The predominant virulence genes were acm and esp. Only 5 VREfm isolated in 2005-2006 had intact Tn1546, while 81% showed Tn1546 with deleted left extremity and insertion of IS1251 between the vanS and vanH genes. Multilocus sequence typing analysis permitted the identification of 9 different sequence types (STs), with 5 being new ones (656, 657, 658, 659, and 660). Predominant STs were ST412 and ST478, all belonging to CC17, except ST658. This is the first report of the ST78 in Brazil. (c) 2012 Elsevier Inc. All rights reserved.

Molecular epidemiology of the nasal colonization by methicillin-susceptible Staphylococcus aureus in Swiss children

Nasal carriage of Staphylococcus aureus contributes to an increased risk of developing an infection with the same bacterial strain. Genetic regulatory elements and toxin-expressing genes are virulence factors associated with the pathogenic potential of S. aureus. We undertook an extensive molecular characterization of methicillin-susceptible S. aureus (MSSA) carried by children. MSSA were recovered from the nostrils of children. The presence of Panton-Valentine leukocidin (PVL), exfoliatins A and B (exfoA and exfoB), and the toxic-shock staphylococcal toxin (TSST-1) and agr group typing were determined by quantitative PCR. A multiple-locus variable-number of tandem repeat analysis (MLVA) assay was also performed for genotyping. Five hundred and seventy-two strains of MSSA were analysed. Overall, 30% were positive for toxin-expressing genes: 29% contained one toxin and 1.6% two toxins. The most commonly detected toxin gene was tst, which was present in 145 (25%) strains. The TSST-1 gene was significantly associated with the agr group 3 (OR 56.8, 95% CI 32.0-100.8). MLVA analysis revealed a large diversity of genetic content and no clonal relationship was demonstrated among the analysed MSSA strains. Multilocus sequence typing confirmed this observation of diversity and identified ST45 as a frequent colonizer. This broad diversity in MSSA carriage strains suggests a limited selection pressure in our geographical area.

Endocarditis due to Tropheryma whipplei: rapid detection, limited genetic diversity, and long-term clinical outcome in a local experience

The characteristic features of Whipple's disease include abdominal pain, diarrhoea, wasting, and arthralgias, with the causative agent, Tropheryma whipplei, being detected mainly in intestinal biopsies. PCR technology has led to the identification of T. whipplei in specimens from various other locations, including the central nervous system and the heart. T. whipplei is now recognized as one of the causes of culture-negative endocarditis, and endocarditis can be the only manifestation of the infection with T. whipplei. Although it is considered a rare disease, the true incidence of endocarditis due to T. whipplei is not clearly established. With the increasing use of molecular methods, it is likely that T. whipplei will be more frequently identified. Questions also remain about the genetic variability of T. whipplei strains, optimal diagnostic procedures and therapeutic options. In the present study, we provide clinical data on four new patients with documented endocarditis due to T. whipplei in the context of the available published literature. There was no clinical involvement of the gastrointestinal tract. Genetic analysis of the T. whipplei strains with DNA isolated from the excised heart valves revealed little to no genetic variability. In a selected case, we describe acridine orange staining for early detection of the disease, prompting early adaptation of the antibiotic therapy. We provide long-term follow-up data on the patients. In our hands, an initial 2-week course of intravenous antibiotics followed by cotrimoxazole for at least 1 year was a suitable treatment option for T. whipplei endocarditis.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Switzerland: sampling only invasive isolates does not allow a representative description of the local diversity of clones

We conducted a molecular study of MRSA isolated in Swiss hospitals, including the first five consecutive isolates recovered from blood cultures and the first ten isolates recovered from other sites in newly identified carriers. Among 73 MRSA isolates, 44 different double locus sequence typing (DLST) types and 32 spa types were observed. Most isolates belonged to the NewYork/Japan, the UK-EMRSA-15, the South German and the Berlin clones. In a country with a low to moderate MRSA incidence, inclusion of non-invasive isolates allowed a more accurate description of the diversity.

Study of Staphylococcus aureus pathogenic genes by transfer and expression in the less virulent organism Streptococcus gordonii

Because Staphylococcus aureus strains contain multiple virulence factors, studying their pathogenic role by single-gene inactivation generated equivocal results. To circumvent this problem, we have expressed specific S. aureus genes in the less virulent organism Streptococcus gordonii and tested the recombinants for a gain of function both in vitro and in vivo. Clumping factor A (ClfA) and coagulase were investigated. Both gene products were expressed functionally and with similar kinetics during growth by streptococci and staphylococci. ClfA-positive S. gordonii was more adherent to platelet-fibrin clots mimicking cardiac vegetations in vitro and more infective in rats with experimental endocarditis (P < 0.05). Moreover, deleting clfA from clfA-positive streptococcal transformants restored both the low in vitro adherence and the low in vivo infectivity of the parent. Coagulase-positive transformants, on the other hand, were neither more adherent nor more infective than the parent. Furthermore, coagulase did not increase the pathogenicity of clfA-positive streptococci when both clfA and coa genes were simultaneously expressed in an artificial minioperon in streptococci. These results definitively attribute a role for ClfA, but not coagulase, in S. aureus endovascular infections. This gain-of-function strategy might help solve the role of individual factors in the complex the S. aureus-host relationship.

Candida parapsilosis endocarditis: a comparative review of the literature

Fungal endocarditis (FE) is an uncommon disease, and while accounting for only 1.3-6% of all cases of infectious endocarditis, it carries a high mortality risk. Although Candida albicans represents the main etiology of FE, C. parapsilosis is the most common non-albicans species. We report the case of a 32-year-old man with a history of prior intravenous drug (IVD) use hospitalized with endocarditis due to C. parapsilosis and review all 71 additional cases documented in the literature. A retrospective analysis of the 72 C. parapsilosis cases compared to 52 recently reviewed cases of C. albicans endocarditis was conducted to identify organism-specific clinical peculiarities. The most common predisposing factor for C. parapsilosis endocarditis (41/72; 57.4%) involved prosthetic valves followed by IVD use (12/72; 20%). Peripheral embolic and/or hemorrhagic events occurred in 28/64 (43.8%) patients, mostly in cerebral and lower limb territories. Overall mortality was 41.7%. Combined surgical and clinical treatment was associated with a lower mortality. Few patients received the newer antifungal agents, and it would appear that more experience is required for their use in the treatment of C. parapsilosis endocarditis.

Streptococcus bovis clone causing two episodes of endocarditis 8 years apart

A patient had endocarditis caused by Streptococcus bovis twice 8 years apart. According to pulsed-field gel electrophoresis (PFGE) the two isolates were identical. Seven unrelated blood isolates of S. bovis yielded unique PFGE patterns. Considering this heterogeneous population structure our findings demonstrate the long-term persistence of an S. bovis clone in a patient with recurrent endocarditis.