Transferable mechanisms of quinolone resistance are more frequent among enterotoxigenic Escherichia coli isolates displaying low-level quinolone resistance

This study analysed the mechanisms of quinolone resistance among enterotoxigenic Escherichia coli (ETEC) in a periurban area of Lima, Peru. The susceptibility to nalidixic acid and ciprofloxacin, the role of Phe-Arg-b-Naphtylamyde inhibitable-(PAbN) efflux pumps, the presence of mutations in gyrA and parC as well as the presence of aac(6')Ib-cr, qepA, qnrA, qnrB, qnrC, qnrD, qnrVC and oqxAB were determined in 31 ETEC from previous case/control studies of children's diarrhoea. Discordances between disk diffusion, with all isolates showing intermediate or fully resistance to nalidixic acid, and minimal inhibitory concentration (MIC), with 7 isolates being below considered resistance breakpoint, were observed. Twenty-one isolates possessed gyrA mutations (19 S83L, 2 S83A). AAC(6') Ib-cr, QnrS, QnrB and QepA were found in 7, 6, 2 and 1 isolates respectively, with 3 isolates presenting 2 transferable mechanisms of quinolone resistance (TMQR) concomitantly. TMQR were more frequent among isolates with MIC to nalidixic acid ranging from 2 to 16 mg/L (p=0.03), while gyrA mutations were more frequent among isolates with nalidixic acid MIC >= 128 mg/L (p=0.0002). In summary, the mechanisms of quinolone resistance present in ETEC isolates in Peru have been described. Differences in the prevalence of underlying mechanisms associated with final MIC levels were observed. The results suggest two different evolutive strategies to survive in the presence of quinolones related to specific bacterial genetic background.

An Adult Case of Paratesticular Spindle Cell Rhabdomyosarcoma

Paratesticular rhabdomyosarcoma (RMS) occurs more frequently in children and is rare in adults. Embryonal RMS is the most common subtype of paratesticular RMS. Spindle cell is a rare variant of embryonal RMS and is associated with a favorable prognosis in children. Data in adults is lacking. We present a case of paratesticular RMS in a 24-year-old man.

Resource Utilization and Temporal Segregation of Scarabaeinae (Coleoptera, Scarabaeidae) Community in a Caatinga Fragment

We characterized dung beetles food preference and diel activity and examined the way such characteristics may structure a Scarabaeinae community in a dry forest. We sampled a fragment of Arboreal Caatinga in Milagres, Bahia, Brazil, during the dry and wet seasons, using baited pitfall (bovine spleen, human feces, cow dung, and rotten banana). Species were classified by activity (nocturnal and diurnal) and food preference (coprophagous, necrophagous, saprophagous, copro-necrophagous, and generalist). In total, 1,581 individuals belonging to 16 morphospecies were sampled, with six new records for Caatinga. The dung beetles were mainly from generalist and coprophagous species; seven species presented nocturnal activity, and five were diurnal. There was higher species richness during the day and greater abundance during the night. Species composition differences were influenced by functional guilds and beetle size according to temporal segregation. These factors may be related to physiological, morphological, and behavioral differences.

Short communication: Detection of Shiga toxin-producing Escherichia coli (STEC) in healthy cattle and pigs in Lima, Peru

The aim of this study was to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) in cattle and pigs as a possible STEC reservoir in Lima, Peru. One hundred and fourteen cattle and 112 pigs from 10 and 4 farms, respectively, were studied. Five E. coli colonies per culture were studied by a multiplex real-time PCR to identify Shiga toxin-producing (stx1, stx2, eaeA), enterotoxigenic (lt, st), enteropathogenic (eaeA), enteroinvasive (ipaH), enteroaggregative (aggR), and diffusely adherent E. coli (daaD). Shiga toxin-producing E. coli were isolated from 16 cattle (14%) but none from pigs. stx1 was found in all bovine isolates, 11 of which also carried eaeA genes (69%); only 1 sample had both stx1 and stx2. Thirteen stx-positive strains were classified as Shiga-toxigenic (81%) using an enzymatic immunoassay, 2 STEC strains were from serogroup O157 (13%), and 7 were sorbitol negative (44%). Enteropathogenic E. coli were detected more frequently in cattle (18%, 20/114) than in pigs (5%, 6/112). To our knowledge, this is the first study on the prevalence of STEC in farms animals in Peru using molecular methods. Further studies are needed in a large number of farms to determine the relevance of these findings and its consequences for public health.

Variable selection patterns on the labellum shape of Geoblasta pennicillata, a sexually deceptive orchid

By mimicking shape and female mating pheromones, flowers of sexually deceptive orchids attract sexually excited males which pollinate them while trying to copulate. Although many studies have demonstrated the crucial importance of odour signals in these systems, most flowers pollinated by pseudocopulation resemble, at least superficially, an insect body and these visual cues may be important to cheat pollinators. In this 2-year study, we show that the shape of the labellum of Geoblasta pennicillata is a target of pollinator-mediated natural selection. Contrary to our expectations, plants with a labellum shape more similar to female wasps were not favoured. The strength and pattern of phenotypic selection varied between study years and sexual functions. Although selection through female success was probably associated to the fine-tuning of the mechanical fit between flower form and male wasp, shape was the target of natural selection through male success in both study years indicating that male wasps use this trait when choosing flowers. The imperfect mimicry and patterns of selection observed indicated that an exact imitation is not needed to attract and deceive the pollinators and they suggested a receiver perceptual bias towards uncommon phenotypes.

The faces of mast cell disease: bone marrow infiltrates in 3 patients with systemic mastocytosis

The clinical spectrum of mast cell disease ranges from relatively innocuous and histologically subtle urticarial skin lesions to an aggressive and fatal leukemic form of mast cell proliferation. Not surprisingly, mast cell infiltrates may show significant microscopic heterogeneity, particularly in the bone marrow, the most common site of involvement in systemic mastocytosis (SM). Herein, 3 cases are presented to illustrate the clinical and morphologic heterogeneity of mast cell disease: the first patient, with long standing urticaria pigmentosa, developed anemia and thrombocytopenia; the second patient presented with a pathologic fracture; and the third patient was suspected to have refractory anemia. Upon bone marrow examination, all 3 patients showed mast cell infiltration with distinct morphologic features and all met the WHO criteria for aggressive systemic mastocytosis. Histochemical methods continue to play a role in the identification of mast cells, with some limitations depending on the degree of differentiation of the mast cells and tissue processing methods. Immunohistochemistry has contributed to the identification of mast cells. Coexpression of CD117 and CD25, as well as expression of the more specific immunohistochemical marker tryptase, is seen in systemic SM. The latter may also be employed as a serum marker in the diagnosis and follow-up of patients with SM. The mast cells, in the majority adults with SM, have somatic point mutations of KIT.

[Morphological characterization of annatto fruits 9bixa orellana L.) and its correspondence with protein and isoenzym patterns]

A group of 32 annatto genotypes collected in five Venezuelan regions (Oriente, Centro, Llanos, Andes and Amazonas) and in Brazil were used for morphological studies. The fruit variables with the greatest discriminatory power in the formation of groups were capsule size, spinosity and seed size. On the other hand, an association group among the variables spinosity, spine length, dehiscence and apex shape were formed, also a proportional association between capsule and seed size, and between dehiscent capsule and brown coloured seeds. Additionally, in order to discriminate morphological variables behaviour in respond to electrophoretic variables, a group of protein and isozyme bands associated with fruit characteristics were established. Therefore, a classification system of this species was possible using morphological studies of the capsules, even though a determined association relating morphological and molecular patterns was not found.

[Identification and genetic variability of annatto genotypes (Bixa orellana L.) by means of hydrosoluble proteins and isoenzymes]

In order to identify and to determine the genetic variability of 36 annatto genotypes (Bixa orellana L.) collected in five Venezuelan regions (Oriente, Centro, Llanos, Andes and Amazonas) and in Brazil, hydrosoluble protein patterns as well as specific isozyme patterns (alpha-esterase, beta-esterase and peroxidase) were studied using extracts of germinated annatto seeds with radicles of 10 to 15 mm long. Each electrophoretic system allowed genotype discrimination by means of unique banding patterns: both the hydrosoluble protein and the electrophoretic system of beta-esterase with nine banding patterns each; whilst alpha-esterase and peroxidase discriminated eight and three genotypes, respectively. On the other hand, a combination of all the systems permitted a greater discrimination since 34 out of 36 genotypes could be distinguished. Eight mayor groups were formed that showed high levels of genetic diversity (40 to 60%) with no association between geographic and genetic distances, probably because of human influence in the aleatory distribution of this crop. Results obtained indicated that using electrophoretic banding patterns, a classification system could be established for identification and genetic variability purposes in this species.

Delayed gastric emptying and gastroesophageal reflux: a pathophysiologic relationship

BACKGROUND

Delayed gastric emptying (DGE) is frequent in patients with gastroesophageal reflux (GER), but its pathophysiologic role has not yet been established. To identify a relationship between DGE and GER, we assessed whether DGE increases esophageal acid exposure and the related importance of possible mechanisms.

METHODS

Thirty pediatric patients with pathological GER were divided according to gastric emptying scintigraphy into a DGE group (n = 14) and normal-emptying group (n = 16). The esophageal pH-monitoring parameters of the two groups were compared with respect to the individual variation between postprandial and fasting periods.

RESULTS

Patients with DGE had less total acid exposure than did those with normal emptying, but patients in both groups had a pathological fraction of time when pH was below 4 in both the postprandial (median: 18 vs. 27.6; P = 0.49) and fasting (8.5 vs. 23.9; P = 0.01) periods. Patients in the normal-emptying group had similar fraction of time when pH was below 4 in the postprandial and fasting periods. However, patients in the group with DGE had a fraction of time when pH was below 4 in the postprandial period that was almost double that presented in fasting period (postprandial to fasting ratio: 2.11:0.90; P = 0.002). The postprandial to fasting ratio for episodes per hour was similar in the two groups (1.81 vs. 1.79; P = 0.62). Patients with DGE had a significantly higher frequency of long episodes in the postprandial period than did those with normal emptying (62.5% vs. 38.2%; P = 0.04). The occurrence of the longest episode in the postprandial period was also significantly higher for patients with DGE (57.1% vs. 6.2%; P = 0.003).

CONCLUSIONS

DGE seems to accentuate postprandial reflux by increasing the volume of refluxate per episode of reflux through an underlying incompetent lower esophageal sphincter.

Startle reactivity and PTSD symptoms in a community sample of women

Exaggerated startle and PTSD symptoms have been investigated primarily in relation to acute or Type I stressors. The present study examined PTSD symptoms and startle eyeblink response in relation to chronic or Type II stressors. Type II stressors were operationally defined as high levels of childhood corporal punishment and high levels of current partner aggression. This study recruited a sample of 52 women from a metropolitan community and administered several questionnaires assessing experience of corporal punishment in childhood, current intimate partner aggression and level of PTSD symptoms. Following questionnaires, women were presented with eight auditory startle probes (white noise). Results showed that both childhood corporal punishment and intimate partner aggression were associated with women's PTSD symptom scores. However, only PTSD symptom scores were associated with reduced startle. Results are discussed in light of Type I and Type II stressors, and recent suggestions in the PTSD literature that a subgroup of individuals may experience physiological suppression rather than heightened physiological reactivity.

The nuts and bolts of behavioral observation of marital and family interaction

Despite considerable discussion in the literature about the advantages of observational research and the relative benefits of different coding systems and strategies, little is written about the actual implementation of this assessment strategy. This paper presents an overall framework as well as the essential components involved in collecting (selection of task, setting, unit of analysis, and coding system) and coding (transcribing, selecting and training coders, transforming data, and analyzing reliability) of observational data. To achieve success with observational methods, we emphasize several issues, including (a) the research question as the motivator for all decisions, (b) the interrelatedness of tasks, and (c) the implications of decisions early in the process for later stages of analysis and interpretation. Investigators are encouraged to communicate the details of their observational and coding procedures so that these methods are readily accessible for purposes of replication and comparison.

Metastatic thyroid carcinoma arising from congenital goiter due to mutation in the thyroperoxidase gene

A very large cervical tumor that extended to the upper mediastinum was seen in a newborn after an uneventful pregnancy. The computed axial tomography scan confirmed the presence of a solid mass with precise limits and scattered foci of calcifications situated in the anterolateral region of the neck. The infant underwent thyroidectomy on the seventh day after birth. Pathological examination revealed a follicular carcinoma of the thyroid and probable dyshormonogenetic hyperplastic goiter. At 5 months of age, whole body scans indicated the presence of lung and bone metastases, which were treated with therapeutic doses of radioiodine. Genomic DNA was obtained from the newborn, her parents, her paternal aunt, and her paternal grandparents. Denaturing gradient gel electrophoresis analysis of PCR fragments corresponding to exon 14 of the thyroid peroxidase (TPO) gene indicated the presence of a mutant TPO allele present in the propositus, her father, and her paternal grandmother. Sequencing of the TPO gene demonstrated a mutation resulting from an insertion of a single extra cytosine in a stretch of seven cytosines at positions 2505-2511. The insertion caused a frame shift and a stop signal in exon 16. This sequence would translate into a structurally modified and probably inactive TPO protein. We conclude that the aggressive thyroid metastatic carcinoma arose from a dyshormonogenetic goiter caused by a defective TPO protein.

Wilderness camping for the diabetic

Wilderness camping presents a definite challenge to the teen-age diabetic. For the past three years groups of juvenile diabetics sponsored by the Twin Cities Diabetes Association have ventured into the Boundary Waters Canoe Area in northern Minnesota. Accompanied by a trail guide and a physician, these young men have learned to live with their diabetes under extreme circumstances. Their camping and medical supplies are discussed as well as their exchange lists and dietary management.