Fecal carriage of extended-spectrum ß-lactamase-producing Enterobacteriaceae in Korean community and hospital settings.

PURPOSE: The assessment and early recognition of risk factors for infections due to extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) are important for infection control and proper treatment. The aim of the present study was to investigate the prevalence of fecal carriage of ESBL-E in healthy individuals and hospitalized high-risk patients in Korea and to compare the characteristics of ESBL-E in these two groups. METHODS: A total of 384 samples from 290 healthy individuals and 94 high-risk patients were collected. The screening of ESBL-E was performed using a commercial chromogenic medium. Bacterial identification and antibiotic susceptibility testing were performed using the Vitek 2 system. RESULTS: The prevalence of ESBL-E carriage was 20.3 % in healthy individuals and 42.5 % in high-risk patients. Escherichia coli comprised a large majority (96.6 %) of the isolates from healthy individuals, but Klebsiella pneumoniae was more commonly detected (45.0 %) in high-risk patients than in healthy individuals. K. pneumoniae isolates exhibited significantly higher resistance to ceftazidime, ampicillin, and carbapenem, and E. coli exhibited higher resistance to cefotaxime. E. coli from high-risk patients exhibited significantly higher resistance to levofloxacin and cefepime than that from healthy individuals. CONCLUSIONS: We demonstrated the high prevalence of ESBL-E carriage in Korea and clarified the characteristics of ESBL-E carriage in healthy individuals and high-risk patients. The distribution and antibiotic susceptibility of colonizing ESBL-E were different between the group of healthy individuals and the high-risk patients. Active surveillance of ESBL-E carriage is suggested for infection control, and the use of chromogenic agar appears to be an efficient method.

Detection of heat-labile Escherichia coli enterotoxin with the use of adrenal cells in tissue culture.

Cell-free culture filtrates of heat-labile enterotoxin-producing strains of Escherichia coli are capable of inducing morphological changes and steroidogenesis in monolayer cultures of adrenal cells. These tissue culture changes are simiar to those induced by cholera enterotoxin and cannot be effected by culture filtrates of other enterotoxigenic or enteropathogenic types of bacteria. The results of the tissue culture studies correlated well with those done in the standard intestinal-loop systems and suggest that this tissue culture system could be used to significantly aid epidemiological and molecular studies with heat-labile Escherichia coli enterotoxin.

Therapeutic use of granulocyte-colony stimulating factor could conceal residual malignant cells in patients with AML1/ETO+ acute myelogenous leukemia.

We have experienced a number of cases of AML1/ETO+ acute myelogenous leukemia that showed remission based on bone marrow (BM) morphological criteria, but that revealed clonal abnormalities in most cells by fluorescence in situ hybridization (FISH). Interestingly, most of these cases had AML with AML1/ETO rearrangement. The malignant cells were differentiated and considered mature cells after granulocyte-colony stimulating factor (G-CSF) treatment. To clarify the possible mechanisms underlying this phenomenon, we investigated the expression levels of G-CSFR in AML cells with AML1/ETO rearrangement by flow cytometry and real-time polymerase chain reaction (PCR). The number of AML1/ETO+ cells expressing G-CSFR at baseline was significantly higher than that of AML1/ETO- AML cells (2673 vs 522). In addition, the G-CSFR gene was more highly expressed in AML1/ETO+ cells than in AML1/ETO- cells by real-time PCR. This study reveals that cases showing remission after treatment with G-CSF mostly had leukemia with AML1/ETO rearrangement. This finding might be explained by the higher expression of G-CSF receptor in AML1/ETO+ cells than in AML1/ETO- cells. We recommend that remission should be confirmed by FISH, because malignant clones can be differentiated and masked in morphological examination or chromosome test, especially for AML with AML1/ETO rearrangement.

Comparison of white blood cell counts by WNR, WDF, and WPC channels in Sysmex XN hematology analyzer.

INTRODUCTION: The Sysmex XN modular system (Sysmex, Kobe, Japan) uses a novel technology for white blood cell (WBC) count and differential, using separate channels: white cell nucleated (WNR), WBC differential (WDF), and white progenitor cell (WPC) channels. We questioned how concordant WBC counts would be between them. METHODS: In a total of 6327 consecutive specimens, WBC counts were compared between WNR and WDF channels. They were also compared in three groups of WBC counts and two groups of chemotherapy status. In 508 specimens from the 4361 specimens that were run on the XN-20 module, the WPC channel was used for reflex test. Data were compared using Pearson's correlation, absolute difference, and percent difference (%D). RESULTS: WBC counts between WNR and WDF channels showed very high correlations in total specimens (r = 0.9976) and in the groups of WBC counts and chemotherapy. As WBC count increased, absolute difference increased, while %D decreased (P < 0.0001, both). Percent difference was 1.55% in total specimens and showed the highest value in the severe leukopenia group (<1.0 × 10(9)/L, 6.18%). CONCLUSIONS: This is the first large-scale study on novel channel technology for WBC counts in the Sysmex XN. WBC counts by WNR, WDF, and WPC channels are highly correlated, and they are overall interchangeable and reliable.

In vitro adhesion of K88ac+ Escherichia coli to Peyer's patch and peripheral blood lymphocytes, buccal and rectal epithelial cells or intestinal epithelial brush borders of weaned pigs.

Escherichia coli adhesion assays were conducted using isolated porcine peripheral blood lymphocytes, Peyer's patch lymphocytes, rectal epithelial cells or brush borders, buccal epithelial cells and brush borders from small intestinal epithelial cells. The cells and brush borders were tested for their ability to bind K88-piliated enterotoxigenic E. coli Strain M1823B (K88ac) and E. coli Strain 1476 (K-12, K88ac). Comparison of adhesive phenotypes of 37 weaned pigs as determined by the adhesion assay with small intestinal brush borders and the adherence of K88ac+ enterotoxigenic E. coli to peripheral blood lymphocytes, Peyer's patch lymphocytes and rectal epithelial cells or brush borders, revealed no correlation. In vitro adhesion of K88ac-bearing E. coli was always negative with buccal epithelial cells. K88ac strains varied in their ability to adhere to lymphocytes and rectal epithelial cells or brush borders, indicating that the mechanism of adherence is unrelated to K88-mediated adhesion observed in animals that had the receptors on small-intestinal epithelial-cell brush borders. The non-piliated control E. coli Strain 123 adhered to fresh peripheral blood lymphocytes, and less intensively to frozen-thawed peripheral blood lymphocytes or Peyer's patch lymphocytes. It was concluded that none of the cell types or brush borders, except small-intestinal epithelial-cell brush borders, could be used as targets for phenotyping pigs for the presence of the K88 receptors that have been associated with adhesion and colonization of K88+ enterotoxigenic E. coli in the porcine small intestine.

Persistence of Escherichia coli O157:H7 in experimentally infected swine.

These experiments determined the ability of Escherichia coli O157:H7 to colonize and persist in pigs simultaneously inoculated with other pathogenic E. coli strains. Three-months-old pigs were inoculated with a mixture of five E. coli strains. The mixture included two Shiga toxigenic E. coli (STEC) O157:H7 strains, two enterotoxigenic E. coli (ETEC) strains and one enteropathogenic E. coli (EPEC) strain. A high dose mixture with all five strains at 10(10)CFU/animal (CFU: colony forming units) and a low dose mixture with the STEC strains at 10(7)CFU and the EPEC and ETEC strains remaining at 10(10)CFU were used. The STEC strains persisted in the alimentary tracts of some pigs at 2 months post-inoculation, following inoculation with both the high and low dose mixtures. When all strains were given at 10(10)CFU (high dose) the STEC strains persisted in greater numbers and in more pigs than did the other E. coli strains. The results demonstrated that persistent colonization (> or =2 months) by E. coli O157:H7 can occur in pigs. These findings were similar to those reported from sheep inoculated with the same mixture of E. coli strains. The results are consistent with reports suggesting that pigs have the potential to be reservoir hosts for STEC O157:H7.

Virulence attributes of Escherichia coli isolated from dairy heifer feces.

Escherichia coli isolates from 1,305 (of 6,894) fecal samples collected during the 1991-1992 USDA, Animal and Plant Health Inspection Service, National Health Monitoring System, Diary Heifer Evaluation Project were tested for virulence attributes associated with human enterohaemorrhagic E. coli (EHEC) and the enterotoxin commonly associated with diarrhoea in newborn calves. Single, random isolates from each heifer were hybridized to probes derived from the 60 mDa EHEC plasmid (CVD 419), E. coli attaching and effacing gene (eae), Shiga-like toxin (slt) genes I and II, and E. coli heat-stable enterotoxin a (STaP). Seventy-seven of the 1305 isolates (5.9%) were slt-positive. Most (81.8%) slt-positive E. coli were also CVD 419 and eae-positive. Only 2 of the slt-positive E. coli isolates were STaP-positive.

Lymphocyte localization in lymph nodes of swine: changes induced by lactation.

Localization patterns of lymphocytes taken from mammary, ileal mesenteric, or prefemoral lymph nodes of pubescent or lactating swine were examined. Lymphocyte suspensions were prepared from surgically excised lymph nodes, labeled with 51chromium, and infused back into the donors. Eighteen hours later, pigs were killed, and lymph nodes from six different regions examined for radiolabel. The greatest concentrations of labeled cells were consistently recovered from mesenteric and bronchial lymph nodes, with lesser concentrations recovered from mammary and peripheral nodes. This occurred regardless of origin of the infused cells, and in both pubescent and lactating pigs. Although localization patterns were similar, the total recovery of infused mammary node cells in the six nodes examined was consistently higher in lactating than in pubescent pigs. In contrast, recovery of infused mesenteric node cells was lower in lactating than in pubescent pigs.

Lymphocyte localization in lymph nodes of pubescent, prepartum, and postpartum sheep.

It is generally accepted that lymphocytes associated with the mammary mucosal immune system of non-ruminants may be largely derived from gut-associated lymphoid tissue (GALT). The relationship between the mammary immune system and the GALT of ruminants has not been clearly defined. To address this question, we examined patterns of lymphocyte localization in sheep by 51Cr-labeled lymphocytes following infusion back into donor ewes. We found that lymphocytes taken from mammary lymph nodes of pubescent ewes returned preferentially to mammary nodes, while in prepartum and postpartum ewes, mammary node cells localized equally well in mammary and mesenteric lymph nodes. In contrast, ileal mesenteric lymph node cells from pubescent ewes localized equally well in mammary and mesenteric nodes, but in prepartum and postpartum ewes, localization in mammary nodes was markedly reduced. Comparison of the homing patterns of mammary, mesenteric, and peripheral lymph node cells indicated that mammary node cells behaved similarly to peripheral, rather than mesenteric node cells. This information may be relevant to the extent of communication between the gut and mammary gland in ruminants.

In vitro detection of Shiga toxin using porcine alveolar macrophages.

Porcine alveolar macrophages were found to be highly susceptible to the cytolytic effects of a toxin (Shiga toxin [Stx]) produced by certain strains of Escherichia coli and sometimes associated with clinical disease in pigs and other animals. In comparison with the cells that are most commonly used for Stx detection and titration in vitro (namely, Vero cells), porcine alveolar macrophages appeared to be generally more sensitive and test results could be obtained in less time. Moreover, unlike Vero cells, porcine alveolar macrophages need not be continuously propagated to ensure immediate availability. They can simply be removed from a low-temperature repository, thawed, seeded, and shortly thereafter exposed to the sample in question. These characteristics suggest that porcine alveolar macrophages may be useful in developing a highly sensitive and timely diagnostic test for Stx.

Experimental tracheal and conjunctival infections with Cryptosporidium sp. in pigs.

Tracheal and conjunctival infections with Cryptosporidium were established in pigs by inoculation of oocysts into the trachea and onto the conjunctival sacs. The protozoa were found attached to epithelial cells by an electron-dense band and a folded, vacuolated feeder organelle. They were situated in a parasitophorous vacuole surrounded by a double-layered membrane covered by glycocalyx. Trophozoites, schizonts, merozoites, macrogametes and oocysts could be demonstrated. In addition to normal stages of the life-cycle, degenerate stages were found. The infections with Cryptosporidium were characterized by focal destruction and loss of epithelial cells. Numerous intraepithelial lymphocytes were associated with affected foci, as were infiltrations with lymphocytes, monocytes, and macrophages.

Comparative histopathology of intestinal infections.

Intestinal infections are characterized by a range of histologic changes. Some examples (moving progressively deeper into the tissue from the intestinal lumen) are: 1) Enterotoxigenic E. coli infections are characterized by layers of E. coli adherent to villous epithelium, usually with little or no apparent structural damage to the mucosa. 2) The term enteropathogenic E. coli infection designates a disease characterized by E. coli attached intimately to the epithelial cell surface membrane with effacement of brush border microvilli. 3) Rotavirus infections are characterized by destruction of villous epithelial cells. Parvovirus infections are characterized by destruction of crypt epithelial cells. 4) Some intracellular infections with Campylobacter-like organisms are characterized by epithelial cell hyperplasia. 5) Hemorrhagic colitis in humans, caused by enterohemorrhagic E. coli strains, is characterized by mucosal hemorrhage and edema indicative of vascular necrosis. 6) Most of these lesions are accompanied by some degree of inflammation. Neurophils and lymphocytes mediate some of the structural and functional changes characteristic of these infections. Some changes are mediated directly by microbial products. Additional examples of the complexity of these diseases are: 1) Edema disease of swine is characterized both by adherent E. coli and vascular necrosis (each process mediated by a different bacterial virulence attribute). 2) Rotavirus infections are characterized both by destruction of villous epithelial cells and compensatory hyperplasia of crypt epithelial cells. 3) There is suggestive evidence that enterohemorrhagic E. coli infections may involve: a) destruction of epithelial brush border by attaching-effacing E. coli, b) neutrophil mediated epithelial cell destruction, c) Shiga-like toxin mediated epithelial cell destruction and d) Shiga-like toxin mediated vascular necrosis which in turn causes ischemic damage to epithelium.

Pathogenesis of O157:H7 Escherichia coli infection in neonatal calves.

Cattle have been implicated as an important reservoir of Shiga-like toxin-producing Escherichia coli (SLTEC) O157:H7, enterohemorrhagic E. coli (EHEC) that cause hemorrhagic colitis and hemorrhagic uremic syndrome in humans. Naturally- or experimentally-infected cattle can shed low levels of E. coli O157:H7 long-term, but little is known about the pathogenesis of E. coli O157:H7 infection in cattle. E. coli O157:H7 induce characteristic attaching and effacing (A/E) mucosal lesions in ceca and colons of 1-day-old gnotobiotic piglets and this model is used to study the pathogenesis of SLTEC infections. A/E lesions were not detected in histologic sections of the intestines from adult cattle or 3- to 14-week-old calves infected with E. coli O157:H7. Our objective was to determine if E. coli O157:H7 induce A/E lesions in neonatal calves. Colostrum-deprived calves (< 12-h-old) were bottle-fed with antibiotic-free milk replacer containing 10(10) colony forming units (CFU) of O157:H7 (SLT-I+, SLT-II+) or nonpathogenic E. coli, necropsied 18 h postinfection and their intestines examined histologically. Bacterial attachment, effacement of microvillous borders, and destruction of epithelium were observed in the intestines of the neonatal calves inoculated with E. coli O157:H7. No lesions were observed in calves inoculated with nonpathogenic E. coli. The distribution of intestinal lesions in neonatal calves resembled that in gnotobiotic pigs. Neonatal calves are apparently more susceptible to A/E lesions induced by E. coli O157:H7 than are older calves or adult cattle and provide a model for studying the pathogenesis of E. coli O157:H7 infections in cattle.

Ultrastructure and DNA fragmentation analysis of arterioles in swine infected with Shiga toxin-producing Escherichia coli.

Shiga toxins (Stx) produced by E. coli are potent cytotoxins that affect the vascular system. In humans, systemic toxemia causes renal glomerular damage manifested as hemolytic uremic syndrome. In swine, Stx-producing E. coli (STEC) cause edema disease that is characterized microscopically by segmental arteriolar smooth muscle cell (SMC) lesions. Our objectives were to characterize ultrastructurally and by TUNEL the type of death (apoptosis or necrosis) that occurs in SMCs during edema disease. Increased DNA fragmentation consistent with apoptosis was detected by TUNEL in arterioles of challenged pigs 14-15 days post inoculation. Ultrastructurally 3 grades of SMC lesions were distinguished: 1) Partial loss of SMCs, intercellular space filled with granular cellular debris admixed with membrane bound vacuoles; 2) Complete loss of SMCs; only granular cellular debris and clear vacuoles remained within basement membrane; 3) Inflammation of media; SMCs replaced by a rim of cellular debris located in the periphery of vessel wall. The most common lesion detected was grade 1 (9 ilea and 4 brains). We did not find apoptotic nuclear changes in SMCs or apoptotic inclusion bodies within resident cells. Our study indicates, that (1) Stx produced during edema disease does not cause SMC apoptosis 14-15 dpi; (2) SMCs undergo an array of changes from degeneration to necrosis.

Pathogenesis of Escherichia coli O157:H7 in weaned calves.

Cattle are an important reservoir of Shiga toxin-producing Escherichia coli O157:H7 and other enterohemorrhagic E. coli (EHEC) that cause diarrhea, hemorrhagic colitis, and hemorrhagic uremic syndrome in humans. One strategy for reducing human foodborne EHEC infections is to reduce the levels of EHEC in cattle. Bovine O157:H7 infection models will facilitate identification of virulence factors involved in bovine infections. O157:H7 cause severe diarrhea and attaching and effacing (A/E) mucosal lesions in colostrum-deprived neonatal (< 2 h) calves. We hypothesized that O157:H7 also cause A/E lesions in older calves, but these were not detected in earlier studies because intestinal levels of O157:H7 were too low (< 10(6) CFU/g of tissue) for detection of focally distributed microscopic lesions. Weaned 3- to 4-month-old calves were fasted 48 h, inoculated via stomach tube with 10(10) CFU of O157:H7 or nonpathogenic E. coli, necropsied 4 d pi and examined histologically. Calves inoculated with O157:H7 had higher intestinal levels of inoculated E. coli than control animals. The rectum was the major site of colonization. A/E lesions were seen in the rectum and cecum of calves with high levels of O157:H7. Weaned calves, like neonatal calves, are susceptible to intestinal damage induced by EHEC O157:H7. The rectum and cecum may be principal sites of EHEC O157:H7 colonization during the carrier-shedder state in cattle.

Edema disease as a model for systemic disease induced by Shiga toxin-producing E. coli.

Edema disease (ED) is a naturally occurring disease of weaned pigs caused by host adapted strains of E. coli that produce Shiga toxin (STEC). We determined the temporal and quantitative relationships between intestinal colonization by STEC, levels of Shiga toxin (Stx2e) in the gut, in the blood, and clinical manifestations of ED. Bacterial colonization (10(8) CFU/cm ileum) was highest 4 days post inoculation (pi) in animals that did not develop clinical disease and 6 days pi in animals with clinical signs of ED. The mean time for the development of clinical signs of ED was 6 days pi (range 4-10). Average peak titers of Stx2e in the ileum were 1:16,384 in asymptomatic animals and 1:32,768 in clinical animals. Titers of Stx2e in the feces reflected the toxin titers in the ileum but were lower. Intestinal titers of Stx2e and the density of bacterial colonization were predictive of clinical ED for a group of animals but not for individuals. Approximately 50% of the pigs that had Stx2e titers of > or = 1:4096 and a bacterial density of > or = 10(6) CFU/cm in their ileum, had clinical ED. Pigs that had intestinal Stx2e titers < 1:4096 were asymptomatic. Stx2e was detected in the red cell fraction of blood from some of the pigs with clinical ED and in some that were asymptomatic. Stx2e was not detected in the serum of any animals. ED may be a useful model for predicting the temporal and quantitative relationships between bacterial colonization, Stx levels in the gut and blood and systemic disease for STEC in other species.

Subclinical cryptosporidiosis of turkeys in Iowa.

Cryptosporidium oocysts were found in the feces of 16 of 20 (80%) 17-day-old and 38 of 100 (38%) 24-day-old turkeys in a healthy commercial flock in central Iowa. Mean dimensions of 50 oocysts were 4.5 x 5.3 micron. In experimentally inoculated turkeys and chickens, the parasites frequently infected the ceca, colon, and cloaca, but rarely infected the small intestine or bursa of Fabricius. These data differ from published descriptions of Cryptosporidium baileyi in chickens and turkeys. The results indicate that the cryptosporidia of poultry are not a homogeneous group and demonstrate that Cryptosporidium infections can occur in apparently healthy poultry flocks.

Psychological characteristics of mothers of children with disabilities.

The purpose of this study was to investigate the psychological characteristics of mothers of children with disabilities. This study was performed under the hypotheses that, at the initial diagnosis of the children's disabilities, (1) the mothers suffered from serious psychological distress; (2) the more severe the child's disability was, the more serious the mother's psychological distress was; and that (3) the mother's psychological distress might be resolved within 8 weeks of rehabilitational interventions. The results were as follows: 1) mothers of children with disabilities showed significant (p < 0.05) somatization, depression, anxiety, hostility, and phobic anxiety more so than the control group; 2) there was no significant difference in T scores of 9 dimensions of the Symptom Checklist-90-Revision (SCL-90-R) of the mothers at the initial diagnosis of children's disabilities according to severity of child's disability; 3) there was no significant difference in T scores of 9 dimensions of SCL-90-R in mothers of children with disabilities between at initial evaluation and after 8 weeks of rehabilitational interventions. In conclusion, : 1) mothers of children with disabilities suffered from serious psychological distress at the initial diagnosis of their child's disability; 2) the severity of the child's disability had little influence on the degree of the mother's initial psychological distress; 3) this distress did not resolve with only 8 weeks of rehabilitational interventions. Therefore, effective rehabilitational programs should provide sufficient opportunities for repeated follow-up interviews which offer not only adequate information on the children's disabilities but also psychological support for the mothers.

Linear and whorled nevoid hypermelanosis with delayed psychomotor development.

We report a case of a 25-month-old girl presented to us for the evaluation of a severe delayed psychomotor development who also has pigmentary abnormalities. Linear and whorled hyperpigmentations following Blaschko's lines were noticed on her entire body except on her face, palms, soles, eyes and mucous membranes, which closely resembled those found in hypomelanosis of Ito, but inversely pigmented. Histologic examination revealed basal layer hyperpigmentation without incontinence of pigment or dermal melanophages. Chromosomal analysis of cultured peripheral leukocytes and fibroblasts from the hyperpigmented and the hypopigmented skin revealed normal female karyotype with no evidence of mosaicism or chimerism. This entity represents a kind of neurocutaneous syndrome-referred to by some authors as linear and whorled nevoid hypermelanosis.

Hypertrophic neuropathy with complete conduction block-- hereditary motor and sensory neuropathy type III.

Hypertrophic neuropathy is a non-specific consequence of repeated demyelination and remyelination, encountered in a wide range of inherited and acquired disorders. We report an 11-year-old boy with HMSN III, a kind of hypertrophic neuropathy, with clinical, electrophysiologic and pathologic data. The electrophysiologic studies show complete conduction block in the upper and lower extremities with severe abnormal spontaneous activities. The pathologic findings of sural nerve reveal prominent hypomyelination, onion bulb formation, and severe endoneurial collagenization. Complete conduction block with the preservation of fair to good grade muscle strength is an unusual finding in hypertrophic neuropathy and other peripheral neuropathies, in general.