HACEK endocarditis: state-of-the-art

The HACEK group of bacteria – Haemophilus parainfluenzae, Aggregatibacter spp. (A. actinomycetemcomitans, A. aphrophilus, A. paraphrophilus, and A. segnis), Cardiobacterium spp. (C. hominis, C. valvarum), Eikenella corrodens, and Kingella spp. (K. kingae, K. denitrificans) – are fastidious gram-negative bacteria, part of the normal microbiota of oral and upper respiratory tract in humans. Although their pathogenicity is limited, they are responsible for 1-3% of all infective endocarditis. HACEK endocarditis mostly affect patients with underlying heart disease or prosthetic valves, and are characterized by an insidious course, with a mean diagnosis delay of 1 month (Haemophilus spp.) to 3 months (Aggregatibacter and Cardiobacterium spp.). The advent of continuously monitored blood culture systems with enriched media has erased the need for extended incubation for the diagnosis of HACEK endocarditis. Medical treatment relies on third-generation cephalosporin, with a favorable outcome in 80-90% of cases, with or without cardiac surgery.     

Molecular characterization of class 1 integrons and antimicrobial resistance in Aeromonas strains from foodborne outbreak-suspect samples and environmental sources in Taiwan

One hundred thirty-three Aeromonas spp. isolates were examined for multiple antibiotic resistance phenotypes and prevalence of class 1 integron sequences. Twenty-four (18.0%) of these isolates contained class 1 integron. Seven different class 1 integrons were found among 24strains, with a total of 10 different gene cassettes encoding for resistance to trimethoprim (dfr12 and dfr2d), aminoglycosides (aadA1 and aadA2), beta-lactam antibiotics (oxa2), chloramphenicol (catB3 and catB8), quaternary ammonium amines (qacE2), and 2 ORFs (orfD and orfF) with unknown function. Rate of antibiotic resistance was different between integron-positive and integron-negative strains. Trimethoprim and trimethoprim-sulphamethoxazole resistances were commonly associated with integron, and all of integron-positive isolates were multiple resistant to more than 3 agents. Resistance to as many as 10 antimicrobial agents were observed in integron-positive strains. Several cassette arrays of class 1 integrons identified in this study were not previously reported in Aeromonas strains. This study demonstrates the wide distribution of class 1 integron in Aeromonas spp. isolated from foodborne outbreak-suspect samples and environmental sources in Taiwan.     

A comparative study of five fatal cases of Taxus poisoning

The study presents five fatal cases of poisoning with Taxus spp., all of which were suicides of young people aged between 16 and 26 years. Yew leaves were consumed in four fatalities, whereas a mash from Taxus was ingested in one case. No relevant concentrations of alcohol, narcotic drugs, and pharmaceuticals were determined in postmortem toxicological screening. At forensic autopsy, a widely dilated pupil was found in two decedents. Furthermore, autopsy showed unspecific findings of intoxication in all cases: acute blood congestion of lungs, liver, kidney, and brain as well as dilated cardiac ventricles. No signs of violence could be found in any of the fatalities. Yew leaves were identified in four cases in the stomach and duodenum. 3,5-Dimethoxyphenol, the aglycon of the Taxus ingredient taxicatine, was determined as toxicological evidence for the absorption of yew ingredients. Taxus intoxication could be confirmed by 3,5-dimethoxyphenol concentrations in cardiac blood between 31 and 528 ng/ml for all cases. 3,5-Dimethoxyphenol was also detected in stomach contents as well as in urine, liver, kidneys, and brain samples. Based on the different concentrations of 3,5-dimethoxyphenol determined in the cardiac blood samples, it was concluded that the form of ingestion plays a decisive role in the process of poisoning. Finally, a toxic range for Taxus poisoning based on 3,5-dimethoxyphenol as marker substance is proposed as orientation.     

Detection of antibiotic resistant E. coli and Enterococcus spp. in stool of healthy growing children in Portugal

From stool specimens of 118 healthy children's (1–14 years) in Portugal 92 E. coli and 101 Enterococcu s spp. strains have been isolated. Almost half (40.2%) of the E. coli isolates were resistant to ampicillin, 25.0% were resistant to tetracycline and 26.1% were resistant to streptomycin. Resistance genes detected by specific PCR included bla_TEM and/or bla_SHV and/or bla_CTX‐M (33 of 37 ampicillin and/or cefotaxime resistant isolates), tet (A) and/or tet (B) (16 of 23 tetracycline‐resistant isolates), aad A (19 of 24 streptomycin‐resistant isolates), cml A (in the two chloramphenicol‐resistant isolates), aac (3)‐II with/without aac (3)‐IV (in the four gentamicin‐resistant isolates), sul 1 and/or sul 2 and/or sul 3 (in all trimethoprim/sulfamethoxazole resistant isolates). The majority of the resistant E. coli isolates (69.1%) belonged to phylogenetic group B2. Of the enterococci isolates E. faecium (n = 53), E. faecalis (n = 41), E. hirae (n = 4) and E. durans (n = 3) more than one‐fourth (28.7%) of the isolates were resistant to tetracycline; 21.8% were resistant to erythromycin and 8.9% were resistant to kanamycin. Resistance genes detected by PCR in enterococci included aph (3)′‐IIIa (in all kanamycin‐resistant isolates), aac (6′) (in all gentamicin‐resistant isolates), tet (M) and/or tet (L) (26 of 29 tetracycline‐resistant isolates), erm (B) (17 of 22 erythromycin‐resistant isolates). This survey showed that faecal bacteria such as E. coli and enterococci of healthy growing children's could be a reservoir of antimicrobial resistance genes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Experimental systemic virulence of oral Candida dubliniensis isolates in comparison with Candida albicans,Candida tropicalis and Candida krusei

There are no previous studies on the comparative virulence of Candida dubliniensis with other non‐albicans species. The aim of this study was to compare the virulence and infection kinetics of C. dubliniensis and other species. Candida albicans, C. dubliniensis, Candida tropicalis and Candida krusei (reference strains) were inoculated intravenously in mice. For infection kinetics evaluation, a group of five animals were sacrificed after 6 h, 3, 7, 14 and 21 days. Microbiological evaluations (liver, spleen, kidneys, lungs and brain) and histopathological examination of the kidney were performed. The results of virulence evaluation were analysed using Kaplan–Meier survival analysis (5%). Candida dubliniensis‐inoculated mice survived for longer periods compared with those with C. albicans (P = 0.005). No differences were detected in relation to C. tropicalis (P = 0.326) and C. krusei (P = 0.317). Most of the organs were persistently colonised by C. albicans and C. dubliniensis even by day 21. Tendency of C. krusei clearance was observed in all organs. Fungal masses and renal lesions were observed after inoculation of C. albicans, C. dubliniensis and C. tropicalis. Within the limits of the study, data on survival rate and dissemination capacity suggest that C. dubliniensis is less virulent than C. albicans.     

Nutrients, bioactive non-nutrients and anti-nutrients in potatoes

Globally, potatoes account for only about 2% of the food energy supply, yet they are the predominant staple for many countries. In developed countries, potatoes account for 540 kJ (130 kcal) per person per day, while in developing countries, it is only 170 kJ (42 kcal) per person per day. In addition to energy, which is derived almost entirely from their carbohydrate content, many varieties of potatoes contribute nutritionally important amounts of dietary fibre (up to 3.3%), ascorbic acid (up to 42 mg/100 g), potassium (up to 693.8 mg/100 g), total carotenoids (up to 2700 mcg/100 g), and antioxidant phenols such as chlorogenic acid (up to 1570 mcg/100 g) and its polymers, and anti-nutrients such as α-solanine (0.001–47.2 mg/100 g); and lesser amounts of protein (0.85–4.2%), amino acids, other minerals and vitamins, and other beneficial and harmful bioactive components. Nutrient content depends on a number of factors, with variety being among the most important. Potato biodiversity is vast, with more than 4000 known varieties. Most belong to the species Solanum tuberosum, but another 10 species are cultivated and 200 wild species have been identified. Modern agricultural practices and climate change are contributing to the loss of potato biodiversity, and thus the loss of the genes coding for nutrient biosynthetic pathways. Knowledge of differences in nutrient composition of potatoes related to their genetic diversity will help guide strategies that may contribute to reducing biodiversity loss and improving food and nutrition security.     

临床常见毛孢子菌的鉴定

为了探讨临床常见毛孢子菌（Trichosporon spp.)的鉴定方法，在形态学、营养生理学试验的基础上对临床常见的毛孢子菌－皮瘤毛孢子菌（Trichosporon inkin)、皮毛孢子菌（Trichosporon cutaneum)及阿萨希毛孢子菌（Trichosporon asahii)进行核糖体核糖核酸（rRNA)基因（rDNA)的内转录间区（ITS）扩增，用限制性内切酶Cfr3I、NcoI对聚合酶链反应（PCR）产物进行限制性片段长度多态性（RFLP）分析及序列测定，发现用Cfr13I做酶切，皮毛孢子菌的RFLP带型和阿萨希毛孢子菌、皮瘤毛孢子菌的不同；用NcoI做酶切，皮瘤毛孢子菌的带型与另两者不一致，序列分析的结果与形态学、营养生理学试验一致。结果提示，温度试验、API 20C、RFLP及序列测定可用于鉴定临床常见的毛孢子菌。     

Determination of in vitro susceptibility of ocular Fusarium spp. isolates from keratitis cases and comparison of Clinical and Laboratory Standards Institute M38-A2 and E test methods

We evaluated the susceptibility of 85 Fusarium spp. isolates from cases of fungal keratitis with 8 antifungal drugs using the standard Clinical and Laboratory Standards Institute broth microdilution and E test methods. Members of the Fusarium solani species complex showed consistently higher MICs to the triazole drugs itraconazole, voriconazole, and posaconazole than did members of other species complexes (Fusarium oxysporum and other minor species). High MICs to amphotericin B, natamycin, and echinocandins were consistently obtained with no discrimination based on species or method. Further work is required to determine any potential correlation between MIC and clinical outcome in keratitis.     

Characterization of extended-spectrum beta-lactamases in Salmonella spp. at a tertiary hospital in Durban, South Africa

Extended-spectrum beta-lactamases (ESBLs) were characterized in 41 Salmonella spp. isolates from patients admitted to a pediatric ward of a tertiary hospital in Durban, South Africa. The most common (17/ 41) serotype was Salmonella enterica serotype Typhimurium, followed by S. enterica serotype Isangi (16/41), S. enterica serotype Saint-paul (2/41), S. enterica serotype Kissi (2/41), S. enterica serotype Kivu (2/41), and S. enterica serotype Reading (1/41). All isolates were resistant to ampicillin, amoxicillin-clavulanate, piperacillin, ceftazidime, and aztreonam but susceptible to meropenem. SHV-12 found in 39% of the isolates was the most common ESBL. TEM-63 was produced in 29% and TEM-116 in 10% of the isolates, and TEM-131 was found in 1 isolate. Other ESBLs that were identified included SHV-2 (n = 2), CTX-M-3 (n = 1), CTX-M-15 (n = 2), and CTX-M-37 (n = 5). In addition, CMY-2 (n = 3) and the OXA-1(n = 1) beta-lactamase were also detected. The diversity of ESBLs suggests that its incidence in Salmonellae needs to be monitored.     

Orientobilharzia species: Neglected parasitic zoonotic agents

Parasites of the genus Orientobilharzia belong to Platyhelminthes, Trematoda, Digenea, Schistosomatidae, and the type species is Orientobilharzia turkestanicum. O. turkestanicum was first described by Skrjabin from cattle in Russian Turkestan in 1913. Adult worms of Orientobilharzia species live in the portal veins or intestinal veins of cattle, sheep and other mammals, and often cause orientobilharziasis in China, India, Mongolia, Pakistan, Iraq, Iran in Asia, and Russia and Turkey in Europe. More importantly, the cercariae of Orientobilharzia species can infect humans and often cause cercarial dermatitis. Though Orientobilharzia species have been confirmed as zoonotic agents, they have been largely neglected, compared with other pathogens causing cercarial dermatitis, such as Trichobilharzia spp., Schistosoma spindale and Bilharziella sp., which have attracted considerable attention. Here we review the current status of knowledge on the taxonomy of Orientobilharzia spp., human and animal infections with Orientobilharzia spp., and address some considerations for further work on the systematics and pathogenesis of these organisms.