Modeling microbial ethanol production by E. coli under aerobic/anaerobic conditions: applicability to real postmortem cases and to postmortem blood derived microbial cultures

The mathematical modeling of the microbial ethanol production under strict anaerobic experimental conditions for some bacterial species has been proposed by our research group as the first approximation to the quantification of the microbial ethanol production in cases where other alcohols were produced simultaneously with ethanol. The present study aims to: (i) study the microbial ethanol production by Escherichia coli under controlled aerobic/anaerobic conditions; (ii) model the correlation between the microbial produced ethanol and the other higher alcohols; and (iii) test their applicability in: (a) real postmortem cases that had positive BACs (>0.10 g/L) and co-detection of higher alcohols and 1-butanol during the original ethanol analysis and (b) postmortem blood derived microbial cultures under aerobic/anaerobic controlled experimental conditions. The statistical evaluation of the results revealed that the formulated models were presumably correlated to 1-propanol and 1-butanol which were recognized as the most significant descriptors of the modeling process. The significance of 1-propanol and 1-butanol as descriptors was so powerful that they could be used as the only independent variables to create a simple and satisfactory model. The current models showed a potential for application to estimate microbial ethanol - within an acceptable standard error - in various tested cases where ethanol and other alcohols have been produced from different microbes.

Phospholipase activity after β-endorphin exposure discriminates Malassezia strains isolated from healthy and seborrhoeic dermatitis skin

BACKGROUND

Phospholipase activity and its induction by β-endorphin have been associated with pathogenic Malassezia pachydermatis animal isolates.

OBJECTIVE

To evaluate Malassezia phosholipase activity in human isolates from seborrhoeic dermatitis (SD) and healthy controls before and after β-endorphin exposure.

METHODS

Eighty-four volunteers with or without SD (N = 41) were sampled. Isolated Malassezia strains were incubated in Dixon's medium with and without 100 nmol/L β-endorphin. Subsequently, phospholipase activity was assessed in egg-yolk agar and the results were compared employing Wilcoxon sign test for paired data, chi-squared test and multinomial logistic regression analysis.

RESULTS

A total of 64 Malassezia strains were isolated. SD strains tended to have decreased phospholipase activity before (P = 0.057) and increased after exposure to β-endorphin (P = 0.061) compared to isolates from healthy skin. Phospholipase activity after β-endorphin exposure related to basal enzyme activity as a measure of per strain phospholipase inducibility by β-endorphin did not depend on Malassezia species (P = 0.652). However, this latter biochemical trait discriminates strains isolated from SD lesional and healthy skin (P = 0.036).

CONCLUSION

β-endorphin exposure modifies the in vitro phosholipase activity in Malassezia species isolated from SD lesional skin. This is in accordance with emerging evidence that enhanced local lipase activity is involved in the pathogenesis of SD.

Chemical investigation and antimicrobial properties of mastic water and its major constituents

Mastic water is a commercial flavouring obtained during the steam distillation of mastic resin (the resin of Pistacia lentiscus var. chia) for the production of mastic oil. The mastic water extracts were analysed by GC-MS. The major compounds identified were verbenone, α-terpineol, linalool and trans-pinocarveol. Overall the composition was found to be very different from that of mastic oil. Additional GC-MS revealed the enantiomeric ratio of the chiral constituents of mastic water. The antimicrobial activity of mastic water extract, as well as that of its major constituents, was examined against Escherichia coli, Staphylococcus aureus and Candida spp. including ATCC wild clinical and food-borne strains. Linalool and α-terpineol were found to be the most potent antimicrobial constituents. Finally the stability of mastic water at different temperatures was studied, showing no change in the GC-MS profile of the organic extract for a period of 4months at storage temperatures up to 4°C.

Is birth weight associated with childhood lymphoma? A meta-analysis

Several risk factors have been identified for childhood lymphomas. The purpose of this meta-analysis was to synthesize current evidence regarding the association between birth weight with primarily the risk for non-Hodgkin lymphoma (NHL), given its similarity to acute lymphoblastic leukemia, Hodgkin lymphoma (HL) and any category of lymphoma. Two cohort (278,751 children) and seven case-control studies (2,660 cases and 69,274 controls) were included. Effects estimates regarding NHL, HL and any lymphoma were appropriately pooled using fixed or random effects model in two separate analyses: specifically, high was compared to normal or any birth weight. Similarly, low was compared to normal or any birth weight. No statistically significant association was found between high birth weight, as compared to normal birth weight, and risk for NHL plus Burkitt lymphoma (OR = 1.17, 95% CI = 0.76-1.80, random effects), HL (OR = 0.94, 95% CI = 0.64-1.38, fixed effects) or any plus Burkitt lymphoma (OR = 1.09, 95% CI = 0.76-1.56, fixed effects). A null association emerged when low was compared with normal birth weight for NHL plus Burkitt lymphoma (OR = 1.07, 95% CI = 0.71-1.62, random effects), HL (OR = 0.94, 95% CI = 0.54-1.65, fixed effects) or any plus Burkitt lymphoma (OR = 1.02, 95% CI = 0.79-1.33, fixed effects). Accordingly, no association was found when high or low birth weight was compared to any birth weight. Although current evidence suggests no association, birth weight might be a too crude indicator to reveal a genuine association of fetal growth with specific lymphoma categories; hence, there is an emerging need for use of more elaborate proxies, at least those accounting for gestational week.

Maternal smoking during pregnancy and childhood lymphoma: a meta-analysis

Results from epidemiological studies exploring the association between childhood lymphoma and maternal smoking during pregnancy have been contradictory. This meta-analysis included all published cohort (n = 2) and case-control (n = 10) articles; among the latter, the data of the Greek Nationwide Registry for Childhood Hematological Malignancies study were updated to include all recently available cases (-2008). Odds ratios (ORs), relative risks and hazard ratios were appropriately pooled in three separate analyses concerning non-Hodgkin lymphoma (NHL, n = 1,072 cases), Hodgkin lymphoma (HL, n = 538 cases) and any lymphoma (n = 1,591 cases), according to data availability in the included studies. An additional metaregression analysis was conducted to explore dose-response relationships. A statistically significant association between maternal smoking (any vs. no) during pregnancy and risk for childhood NHL was observed (OR = 1.22, 95% confidence interval, CI: 1.03-1.45, fixed effects model), whereas the risk for childhood HL was not statistically significant (OR = 0.90, 95% CI: 0.66-1.21, fixed effects model). The analysis on any lymphoma did not reach statistical significance (OR = 1.10, 95% CI = 0.96-1.27, fixed effects model), possibly because of the case-mix of NHL to HL. No dose-response association was revealed in the metaregression analysis. In conclusion, this meta-analysis points to a modest increase in the risk for childhood NHL, but not HL, among children born by mothers smoking during pregnancy. Further investigation of dose-response phenomena in the NHL association, however, warrants accumulation of additional data.

Salmonella infection in cattle in Great Britain, 2003 to 2008

Surveillance data for clinical disease in cattle in Great Britain due to Salmonella infections were analysed for the period 2003 to 2008 in order to describe seasonality and to investigate possible associations between Salmonella diagnoses and other variables such as region, climate, age and production type. A clear seasonal pattern was shown for Salmonella infection, coinciding with the second half of the year. The incidence of Salmonella Dublin and Salmonella Typhimurium was highest in the west of the country, which has the greatest cattle density, but this was not a feature of diagnoses with other serovars. Abortion was a more common clinical sign of S Dublin infections, but was relatively unusual in the case of S Typhimurium. The observed clinical picture and age of affected animals were largely determined by the seasonality of dairy cattle calving in Great Britain.

Retrospective analysis of Salmonella isolates recovered from animal feed in Great Britain

To examine feed contamination rates with Salmonella, the diversity of serovars and the antimicrobial resistance of isolates from animal feedingstuffs in Great Britain, and to compare Salmonella strains found in animal feed and in livestock, data collected under voluntary and statutory Salmonella surveillance during the period 1987 to 2006 were analysed retrospectively. The feed contamination rate decreased from 3.8 per cent in 1993 to 1.1 per cent in 2006. A total of 263 Salmonella serovars were recovered: S Mbandaka (11.2 per cent), S Tennessee (10.4 per cent), S Senftenberg (8.4 per cent), S Agona (6.4 per cent), S Montevideo (6.4 per cent) and S Ohio (3.1 per cent) were the most prevalent. S Typhimurium was recovered at a proportion of 1.6 per cent from raw ingredients and 2.4 per cent from finished feed, while S Enteritidis was recovered at a proportion of 0.5 per cent from raw ingredients and 0.6 per cent from finished feed; 14.1 per cent of the isolates were resistant to at least one antimicrobial, and 1.9 per cent were multiresistant. There was no evidence of a statistical association (P<0.05) between the top 10 serovars recovered from feed and from livestock.

Trends in phage types and antimicrobial resistance of Salmonella enterica serovar Enteritidis isolated from animals in Great Britain from 1990 to 2005

Surveillance data for Salmonella enterica serovar Enteritidis incidents and isolations from food animals in Great Britain from 1990 to 2005 were analysed to detect any trends and provide the basis for a comparison between phage types (pt) and antimicrobial sensitivity patterns in human beings and animals. During 2001 to 2005 there was a decrease in incidents involving most species except ducks. Only the numbers of incidents involving pts 6, 6a, 9b and 14b (in ducks) and pts 6a and 13a (in mammals) increased significantly during this period, whereas there were 93 per cent fewer incidents involving pt 4 than in 1990 to 2000. After adjustment for pt, the isolates from ducks were more resistant to nalidixic acid, tetracyclines and sulfonamides, and were more likely to be multiresistant than isolates from chickens. Isolates from turkeys tended to be more resistant to sulfonamides than isolates from chickens. pts 1, 5a, 6, 6a and 35 had the highest level of resistance after adjusting for species. During 2001 to 2005 there was an increase in resistance among pts 1, 6 and 7, in most cases involving nalidixic acid.

Changes in histamine and microbiological analyses in fresh and frozen tuna muscle during temperature abuse

Temperature abuse of tuna (Thunnus alalunga) was carried out in order to assess the histamine buildup in fish-processing facilities where fish can be exposed to high temperatures for short periods of time. Histamine production was studied in tuna loins under different storage and abuse conditions. Tuna was stored at 0-2 degrees C, 3-4 degrees C, and 6-7 degrees C, and abused for 2 h daily at 20 degrees C and 30 degrees C for 7-12 days. Loins abused at 30 degrees C for 2 h daily contained potentially toxic histamine concentrations (67-382 mg kg(-1)) when stored at a low refrigeration temperature (0-2 degrees C), whereas when stored at 6-7 degrees C, the loins contained highly toxic histamine concentrations (544.5-4156.6 mg kg(-1)). Lower histamine concentrations (23-48 mg kg(-1) in loins stored at 0-2 degrees C and 124.7-2435.8 mg kg(-1) in loins stored at 6-7 degrees C) were observed in temperature-abused loins that were initially frozen. An increase over time was observed in most microbial counts tested. Bacteria isolated from the temperature-abused loins showed a varied ability of histamine production, with Morganella morganii, Klebsiella oxytoca, Staphylococcus hominis, and Enterococcus hirae being the most active histamine-producing bacteria.

Microbiological quality of indoor and outdoor swimming pools in Greece: investigation of the antibiotic resistance of the bacterial isolates

During 1997-2005, the microbiological quality and susceptibility of bacterial isolates of swimming pool waters were investigated. A total of 462 water samples were collected from three indoor swimming pools (a teaching pool, a competition public pool, a hydrotherapy pool) and two outdoor swimming pools (a hotel semi-public and a residential private pool) in Northwestern Greece. All water samples were analyzed for the presence of bacteria, protozoa and fungi and susceptibility tests were performed for the bacterial isolates. Sixty-seven percent of the examined water samples conformed to the microbiological standards and 32.9% exceeded at least one of the indicated limits. Out of 107 bacterial isolates, 38 (35.5%) resistant strains were detected. Multi-resistant Pseudomonas alcaligenes, Leuconostoc, and Staphylococcus aureus (isolated from the teaching pool), Staphylococcus wernerii, Chryseobacterium indologenes and Ochrobactrum anthropi (isolated from the competition pool), Pseudomonas aeruginosa, P. fluorescens, Aeromonas hydrophila, Enterobacter cloacae, Klebsiella pneumoniae and S. aureus (isolated from the hydrotherapy pool) and A. hydrophila (isolated from the hotel pool) were detected. The swimming pool with the poorest microbiological quality (THC 500 cfu/ml in 12.1% of the samples, P. aeruginosa counts 1500 cfu/100 ml in 6% of the samples) and the highest prevalence of multi-resistant isolates (73.6%) was the hydrotherapy pool. No Cryptosporidium or Giardia cysts and no Legionella, Mycobacteria and Salmonella were detected, but there were isolations of Candida albicans, Aspergillus spp., Mucor spp., Alternaria spp., Rhizopus spp., Trichophyton spp., and Penicillium spp.

Diarrheic shellfish poisoning due to toxic mussel consumption: The first recorded outbreak in Greece

During the week of 14-20 January 2000, 120 people visited the Emergency Departments of hospitals in Thessaloniki, northern Greece, complaining of acute gastrointestinal illness after eating mussels (Mytilus galloprovincialis). The symptoms indicated diarrhoeic shellfish poisoning, and the toxicity of mussels harvested from Thermaikos Gulf in Thessaloniki during the outbreak was investigated using mouse bioassays. The bioassays revealed toxicity to mice by the mussel samples; while high numbers of toxic algae Dinophysis acuminata were identified in water samples from Thermaikos Gulf. The harvesting of mussels was immediately suspended and a monitoring programme for algal blooms was established from then onwards. During a follow-up of the mussels' toxicity from January 2000 to January 2005, two more mussel samples were found positive for diarrheic shellfish poisoning: one harvested in March 2001 from the area of the outbreak (Thermaikos Gulf) and the other harvested in January 2001 from Amvrakikos Gulf in north-western Greece. However, no sporadic cases or outbreaks were reported during this period.

Intravitreal dirofilariasis: a rare ocular infection

Human ocular dirofilariasis is a zoonotic disease, rare in Europe, caused by filarial nematodes. The parasite is either encysted in a subcutaneous nodule or located under the bulbar conjunctiva. We report the case of a 62-year-old man with intravitreal dirofilariasis, which is a rare site of presentation of the nematode in the human eye. It was located in the fundus area and was surgically removed. The nematode was identified as Dirofilaria repens (D. conjuctiva) by two different Microbiology Departments, making this the fifth report of identified intravitreal dirofilariasis caused by D. repens in the relative literature.

Lack of the appropriate natural killer cell inhibitory receptors in women with spontaneous abortion

Previous studies have revealed that women with unexplained recurrent spontaneous abortions have a limited repertoire of inhibitory KI receptors (inhKIRs) and that the inhKIRs they possess do not have specificity for the human leukocyte antigen (HLA)-Cw molecules that would be expressed on trophoblast. We sought to confirm these findings by direct definition of maternal inhKIR and trophoblastic HLA-Cw allotypes on the placental material of spontaneously missed pregnancies. The study included 30 women undergoing vacuum uterine curettage for first-trimester missed pregnancy (group A; n = 15) or for elective termination of normal pregnancy (group C, n = 15). DNA extracted from isolated decidual and trophoblastic cells was used for molecular detection of maternal inhKIRs (2DL1, 2DL2, 2DL3) and fetal HLA-Cw alleles, respectively. The results revealed that in the group of women who experienced abortion, 60% did not have the full repertoire of three inhKIRs (group A vs group C; p = 0.006); that in five of 15 patients (none in the controls), no epitope matching existed between maternal inhKIRs and trophoblastic HLA-Cw alleles (group A vs group C; p = 0.01); and that more cases were found with limited epitope matching (less than three inhKIRs with specificity for fetal HLA-Cw alleles). The results provide additional evidence that in some cases of spontaneous abortions, the women lack the appropriate inhKIRs to interact with the HLA-Cw molecules on trophoblasts and to deliver signals to inhibit natural killer cell activation and protect the embryo.

The effect of short-time microwave exposures on Escherichia coli O157:H7 inoculated onto chicken meat portions and whole chickens

Small portions of fresh chicken breasts weighting 20 g each and fresh whole chickens, weighting on average 1310 g each, were inoculated with Escherichia coli O157:H7 (10(5)-10(6) cfu/g) and cooked, using two different domestic microwave ovens at full power. The chicken portions were heated for 5, 10, 15, 20, 25, 30, and 35 s and the whole chickens for 22 min. Following exposures, viable counts and temperature measurements were performed. Although the chicken breast portions looked well-cooked after 30 s of MW heating at a mean end-point surface temperature of 69.8 degrees C, a mean concentration of 83 cfu/g E. coli O157:H7 cells was recovered. Elimination of E. coli O157:H7 cells occurred only after 35 s of MW exposure at 73.7 degrees C. When whole chickens were thoroughly cooked by MW heating, the final subsurface temperatures, measured in the thighs and wings, ranged from 60.2 degrees C to 92 degrees C and viable cells of E. coli O157:H7 were recovered from all samples of whole chicken. The results indicate that short time exposures of chicken portions to microwave heating do not eliminate E. coli O157:H7.