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L Herman

Publications and source records attributed to L Herman.

At least 37 records · Page 2Linked to original sources
PubMed2001

Growth of Salmonella in egg white.

Six non-S. Enteritidis strains and eleven S. Enteritidis strains of which 8 were isolated from eggs, were tested on their growth behaviour in fresh eggs and in eggs of 2 and 3 weeks old hold at 20 degrees C. The growth of Salmonella at 20 degrees C was measured at days 6, 13 and 23 after inoculation. Taking the average growth of the different S. Enteritidis and of the non-S. Enteritidis strains, we found that both groups grew very well in fresh eggs. S. Enteritidis strains grew as good in eggs of 2 weeks as in fresh eggs, non-S. Enteritidis strains grew less. When keeping the eggs 3 weeks before inoculation, both groups showed still a relatively high growth. Additional experiments were done on the growth of Salmonella in a minimal medium with an iron source together with the iron chelator conalbumin, and in a medium without iron and conalbumin, to overcome variations in viscosity and in egg composition. After 12 hours incubation at 37 degrees C, both S. Enteritidis and non-S. Enteritidis strains grew better in the presence of iron than in the absence. S. Enteritidis egg isolates behaved more variable than S. Enteritidis non-egg isolates in the presence of iron. To check the influence of pH changes during ageing of eggs, we measured the growth of Salmonella in minimal media (with iron) of pH 8, 8.5, 9 and 9.5. All salmonellae seemed to grow well independently of the pH. Thus the fact that Salmonella grew best in fresh egg white and showed a decreasing growth in stored egg white, is probably not due to a pH effect. We also investigated if the presence of the yolk had an influence on the growth of Salmonella. We saw no general correlation so it seems that no components that could promote the growth of Salmonella diffuse from the yolk. We studied the influence of the egg sources on the variability in growth by comparing experiments done in eggs of 3 different sources. For the different strains we found a variable growth. But in general, the most important conclusion of our experiments is that all Salmonella strains do grow better in fresh egg white than in egg white of 2 or 3 weeks old. These results are contradictory with findings in literature (Humphrey et al., 1993) and must be checked with the European guidelines concerning the storage of eggs. Moreover, we found that even non-S. Enteritidis strains can grow well in egg white. These are not found in naturally contaminated eggs. It doesn't seem probable that S. Enteritidis could penetrate the egg shell easier than other serotypes so we suppose that horizontal transmission of Salmonella in eggs is of less importance than the vertical transmission.

Consumer Product Safety↗
PubMed2000

The presence of intragenically located REP-like elements in Bacillus sporothermodurans is sufficient for REP-PCR typing.

The technique of repetitive extragenic palindromic polymerase chain reaction (REP-PCR) enables the identification and discrimination of clonally related Bacillus sporothermodurans isolates from ultra-high temperature and sterilized milk. The aim of this study was to investigate the genetic basis for the generation of these highly informative REP-PCR patterns. The major 947-bp REP-PCR fragment of B. sporothermodurans was cloned, together with its 5' and 3' flanking sequences. Only partial homology with the REP consensus sequence was established at the borders of the REP-PCR fragment. Moreover, these border sequences were located within two distinct open reading frames, with great homology to the uvrA and uvrB genes of Escherichia coli. The presence of these REP-like elements in B. sporothermodurans was thus sufficient for high resolution REP-PCR typing of this Gram-positive organism. In some cases (and especially with Gram-positives), REP-PCR could thus be considered more as an arbitrary primed PCR, albeit at a somewhat higher annealing temperature and using conserved primers. The random priming effect at the less stringent annealing conditions of REP-PCR was also demonstrated for enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) on another Gram-positive organism, Listeria monocytogenes.

3' Untranslated Regions↗
PubMed1999

Rapid detection of stressed Salmonella spp. in dairy and egg products using immunomagnetic separation and PCR.

The rapid detection of an average of 5.9 stressed Salmonella cells in 25 g of food product using immunomagnetic separation (IMS) and PCR is described. For pasteurised egg yolk, egg yolk powder, ice-cream, whole egg, egg white and cheeses made from pasteurised milk PCR was applied after 16 h of preenrichment in buffered peptone water (BPW) using IMS and alkaline lysis as sample preparation method. For whole egg and egg white the BPW was supplemented with iron. For milk powder, and raw milk cheeses, the 16-h preenrichment in BPW was followed by IMS and a 4-h enrichment in Rappaport-Vassiliadis broth. In the latter case, PCR was applied on the enrichment medium after centrifugation and alkaline lysis. For PCR the primers ST11 and ST15 (Aabo et al., 1993) producing a fragment of 429 bp were used. An internal PCR control, designed to be co-amplified with the target DNA using the same primers but producing a smaller fragment of 240 bp, was used.

Base Sequence↗
PubMed1999

Typing of Listeria monocytogenes strains by repetitive element sequence-based PCR.

Listeria monocytogenes strains possess short repetitive extragenic palindromic (REP) elements and enterobacterial repetitive intergenic consensus (ERIC) sequences. We used repetitive element sequence-based PCR (rep-PCR) to evaluate the potential of REP and ERIC elements for typing L. monocytogenes strains isolated from humans, animals, and foods. On the basis of rep-PCR fingerprints, L. monocytogenes strains were divided into four major clusters matching origin of isolation. rep-PCR fingerprints of human and animal isolates were different from those of food isolates. Computer evaluation of rep-PCR fingerprints allowed discrimination among the tested serotypes 1/2a, 1/2b, 1/2c, 3b, and 4b within each major cluster. The index of discrimination calculated for 52 epidemiologically unrelated isolates of L. monocytogenes was 0.98 for REP- and ERIC-PCR. Our results suggest that rep-PCR can provide an alternative method for L. monocytogenes typing.

Animals↗
PubMed1998

Lyme carditis: a rare presentation in an unexpected setting.

A case is reported of a 27-year-old man who presented to an inner city trauma center after he had experienced several seizure-like episodes. He was diagnosed with Lyme carditis and required 6 weeks of treatment with intravenous ceftriaxone for complete resolution of his symptoms. The case is discussed along with a review of the literature.

Adult↗
PubMed1998

Typing of Bacillus sporothermodurans and other Bacillus species isolated from milk by repetitive element sequence based PCR.

When analysing raw milk for the presence of Bacillus sporothermodurans, 11 Bacillus strains were isolated which could be differentiated from known Bacillus, Brevibacillus and Paenibacillus spp. by different primer specificity in PCR experiments, indicating that they probably belong to Bacillus species as yet undescribed. Using repetitive element sequence based PCR (REP-PCR), these 11 strains could be clearly distinguished from B. sporothermodurans as well as from each other. Eighty-five B. sporothermodurans strains were characterized by a typical REP-pattern. Using REP-PCR combined with separation on non-denaturing polyacrylamide gel electrophoresis and silver staining, individual B. sporothermodurans strains could be discriminated, which was not possible by methods previously published.

Animals↗
PubMed1998

Unidentified Listeria-like bacteria isolated from cheese.

Unidentified Listeria-like bacteria, which lack only one of the phenotypic characteristics used to confirm Listeria spp., were isolated from cheese during routine analysis for Listeria monocytogenes. The VIDAS Listeria assay and the Listeria specific PCR or DNA probe assays used did not identify these strains as Listeria species. This group of bacteria was studied for its homogeneity using rep-PCR and PFGE. Sequence analysis of the 16S rRNA gene showed a homology of 94% to established Listeria spp., implicating a closer relationship than that between Listeria spp. and Brochothrix spp.

Bacterial Typing Techniques↗
PubMed1997

Social relationships among young adults with insulin-dependent diabetes mellitus: ten-year follow-up of an onset cohort.

Past cross-sectional studies have suggested that young adults with insulin-dependent (Type 1) diabetes mellitus (IDDM) may experience problems in their close peer relationships. For 10 years, we have followed an onset cohort of children and adolescents with IDDM (n = 57) and an age-matched group who were originally recruited after an acute illness, accident, or injury (n = 54). Now aged 19-26 years, these two groups were compared in terms of their friendship patterns, dating and love experiences, and sense of loneliness. All subjects in both groups had at least one friend. However, the IDDM group reported fewer friendships overall. The difference was accounted for by the number of less intimate friends. The two groups had similar frequencies of current romantic partners (IDDM = 63%; comparison group = 64%). While dating attitude and dating assertiveness did not differ between groups, some differences were found in terms of experiences of a primary love relationship. IDDM patients experienced less trust and sense of intimate friendship in these love relationships. No differences in loneliness were found. The preponderance of our findings indicate that the two groups had similar patterns and experiences of close peer relationships. Thus, the study does not suggest that IDDM leads to serious problems in forming social relationships for these patients during the transition to young adulthood. On the other hand, the IDDM patients' lower level of trust and intimacy within love relationships are consistent with other findings from this study suggesting specific areas of lowered self-worth that appear in social relationships.

Adolescent↗
PubMed1997

Consequences of irregular versus continuous medical follow-up in children and adolescents with insulin-dependent diabetes mellitus.

OBJECTIVES: To study the social and family characteristics of patients with insulin-dependent diabetes mellitus with irregular versus continuous clinical follow-up and to study the medical outcomes of patients with these follow-up patterns. METHODS: An onset cohort of 61 children and adolescents with insulin-dependent diabetes mellitus and their parents were studied. Aspects of their social and family environment were assessed at study inception and examined in relation to frequency of follow-up early in the course of the illness. Follow-up was dichotomized so that patients with continuous follow-up were compared with patients with irregular follow-up, who were defined as those missing 1 full year of planned medical appointments during the second through fourth years after diagnosis. Patients with irregular and continuous follow-up were compared in terms of acute metabolic complications, glycemic control, and retinopathy status during a 10-year period. RESULTS: Compared with individuals with continuous follow-up, patients with irregular clinical visits were more likely to be from families of lower socioeconomic class levels, have a parental history of separation and divorce, and were members of families that reported being least openly expressive of positive emotions. Poor glycemic control in year 1 was associated with irregular follow-up in years 2 through 4. Patients with irregular follow-up continued to have worse glycemic control in years 2 through 4 than patients with continuous follow-up. However, in years 7 and 10 their glycemic control no longer differed from patients with continuous follow-up. More episodes of diabetic ketoacidosis occurred in the irregular follow-up group. Finally, retinopathy occurred more frequently among those in the irregular follow-up group. CONCLUSION: Early irregular clinical follow-up should be considered a risk factor for complications of insulin-dependent diabetes mellitus.

Adolescent↗
PubMed1997

Psychological adjustment to IDDM: 10-year follow-up of an onset cohort of child and adolescent patients.

OBJECTIVE: To evaluate the psychological adjustment of young adults with IDDM in comparison with similarly aged individuals without chronic illness. RESEARCH DESIGN AND METHODS: An onset cohort of young adults (n = 57), ages 19-26 years, who have been followed over a 10-year period since diagnosis, was compared with a similarly aged group of young adults identified at the time of a moderately severe, acute illness (n = 54) and followed over the same 10-year period. The groups were assessed at 10-year follow-up in terms of 1) sociodemographic indices (e.g., schooling, employment, delinquent activities, drug use), 2) psychiatric symptoms, and 3) perceived competence. In addition, IDDM patients were examined for longitudinal change in adjustment to diabetes. RESULTS: The groups differed only minimally in terms of sociodemographic indices, with similar rates of high school graduation, post-high school education, employment, and drug use. The IDDM group reported fewer criminal convictions and fewer non-diabetes-related illness episodes than the comparison group. There were no differences in psychiatric symptoms. However, IDDM patients reported lower perceived competence, with specific differences found on the global self-worth, sociability, physical appearance, being an adequate provider, and humor subscales. The IDDM patients reported improving adjustment to their diabetes over the course of the 10-year follow-up. CONCLUSIONS: Overall, the young adults with IDDM appeared to be as psychologically well adjusted as the young adults without a chronic illness. There were, however, indications of lower self-esteem in the IDDM patients that could either portend or predispose them to risk for future depression or other difficulties in adaptation.

Acute Disease↗
PubMed1996

Repetitive element sequence based polymerase chain reaction for typing of Brucella strains.

A collection of 40 Brucella strains, including 19 clinical B.canis isolates, was analyzed using ERIC-PCR and REP-PCR. PCR amplification using primers REP 1R-I and REP 2-I provided distinct patterns for Brucella spp. All Brucella strains could be discriminated at least to the species level. ERIC-PCR, employing ERIC 1R and ERIC 2 as primers was less discriminative for Brucella, only allowing a discrimination to the genus level with occasional discrimination between individual strains. It can be concluded that rep PCR is a promising fingerprinting method for the evaluation of an outbreak.

Animals↗
PubMed1996

The WHO multicenter study on Listeria monocytogenes subtyping: random amplification of polymorphic DNA (RAPD).

As part of a WHO multicenter study on Listeria monocytogenes subtyping methods the random amplification of polymorphic DNA (RAPD)-technique was evaluated. Six participants were asked to use a standard protocol to analyse a set of 80 L. monocytogenes strains. This set contained 22 groups of epidemiologically linked isolates and 11 pairs of duplicate strains. Using three different 10-mer primers the median reproducibility of the RAPD-results obtained by the six participants was 86.5% (range 0-100%). Failure in reproducibility was mainly due to results obtained with one particular primer. The number of epidemiological groups found to be homogeneous varied from 1-22 (median 16). However, for some groups an inhomogeneity was found by the majority of participants. The overall correlation between the results from the different participants ranged from 32 to 85%.

Bacterial Typing Techniques↗
PubMed1996

Repetitive element sequence-based PCR for species and strain discrimination in the genus Listeria.

Repetitive element sequence-based PCR (rep-PCR) was used to generate DNA fingerprints for Listeria spp. Two primer sets (REP 1R-I REP 2-I and ERIC 1R ERIC 2) used in respectively REP- and ERIC-PCR revealed that bacteria of the genus Listeria possess short repetitive extragenic palindromic elements and enterobacterial repetitive intergenic consensus sequences. Specific band profiles obtained by ERIC-PCR enabled the identification of Listeria species. With both REP- and ERIC-PCR the L. monocytogenes serotypes 1/2a, 1/2b, 1/2c, 3b and 4b could be clearly distinguished from each other. Within the serotype 1/2a, REP-PCR showed a higher discriminative potential than ERIC-PCR and a comparable discriminative potential as RAPD combining 3-4 primers.

Base Sequence↗