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Biomedical subjects

D Pierard

Publications and source records attributed to D Pierard.

At least 19 recordsLinked to original sources
PubMed2006

Quantitative risk assessment of Campylobacter spp. in poultry based meat preparations as one of the factors to support the development of risk-based microbiological criteria in Belgium.

The objective of this study was to do an exercise in risk assessment on Campylobacter spp. for poultry based meat preparations in Belgium. This risk assessment was undertaken on the demand of the competent national authorities as one of the supportive factors to define risk-based microbiological criteria. The quantitative risk assessment model follows a retail to table approach and is divided in different modules. The contamination of raw chicken meat products (CMPs) was represented by a normal distribution of the natural logarithm of the concentration of Campylobacter spp. (ln[Camp]) in raw CMPs based on data from surveillance programs in Belgium. To analyse the relative impact of reducing the risk of campylobacteriosis associated with a decrease in the Campylobacter contamination level in these types of food products, the model was run for different means and standard deviations of the normal distribution of the ln[Camp] in raw CMPs. The limitation in data for the local situation in Belgium and on this particular product and more precisely the semi-quantitative nature of concentration of Campylobacter spp. due to presence/absence testing, was identified as an important information gap. Also the knowledge on the dose-response relationship of Campylobacter spp. was limited, and therefore three different approaches of dose-response modelling were compared. Two approaches (1 and 2), derived from the same study, showed that the reduction of the mean of the distribution representing the ln[Camp] in raw CMPs is the best approach to reduce the risk of Campylobacter spp. in CMPs. However, for the simulated exposure and approach 3 it was observed that the reduction of the standard deviation is the most appropriate technique to lower the risk of campylobacteriosis. Since the dose-response models used in approach 1 and 2 are based on limited data and the reduction of the mean corresponds with a complete shift of the contamination level of raw CMPs, demanding high efforts from the poultry industry, it is proposed to lower the standard deviation of the concentration of Campylobacter spp. in raw CMPs. This proposal corresponds with the elimination of the products that are highly contaminated. Simulation showed that eating raw chicken meat products can give rise to exposures that are 10(10) times higher than when the product is heated, indicating that campaigns are important to inform consumers about the necessity of an appropriate heat treatment of these type of food products.

Animals↗
PubMed2006

Septicemia due to Solobacterium moorei in a patient with multiple myeloma.

We report a case of bacteremia caused by Solobacterium moorei, an anaerobic, non-sporulated Gram-positive bacillus in a patient with a multiple myeloma. The source of infection was presumably related to multiple dento-alveolar abscesses. This is the first recovery of S. moorei from blood cultures.

Aged↗
PubMed2003

Sensitivity of methods for the isolation of Escherichia coli O157 from naturally infected bovine faeces.

At present, no standard protocol has been described to detect the presence of Escherichia coli O157 in cattle faeces. Therefore, the sensitivity of 26 different isolation methods was determined in order to recommend a method of choice. Faeces samples from 17 different beef cattle at a farm previously found positive for E. coli O157 were subdivided into a total of 40 samples. It was not known whether the 17 cattle shed E. coli O157 at the time of sampling. At another farm where cattle have been found negative for E. coli O157 on different occasions, five faeces samples were collected. Two methods yielded the highest sensitivity (74%): 6h enrichment in modified tryptone soya broth supplemented with novobiocin (mTSBn) followed by an immunomagnetic separation (IMS) with (i) Dynal beads or (ii) Captivate beads and selective plating on Rainbow agar (RA) plates. Enrichment for 6h was significantly better than 24h enrichment. Only after 24h, buffered peptone water (BPw) was significantly better than mTSBn. A sensitivity of 82% was obtained only when the two most sensitive tests were done simultaneously. Because none of the tests gave 100% sensitivity, it can be concluded that isolation rates of E. coli O157 from bovine faeces using only one of the tested procedures results in an underestimation of the incidence of E. coli O157 in cattle. Performing more than one test on the samples must be considered.

Animals↗
PubMed2003

Isolation and molecular characterization of Escherichia coli O157 isolated from cattle, pigs and chickens at slaughter.

From 1999 until 2001, 3625 food samples were examined for the presence of Escherichia coli O157. Samples were from bovine origin (ground beef, n=549; carcasses, n=2452), calves (carcasses, n=147), chicken (breast, n=203; carcasses, n=71) and pigs (carcasses, n=85; trimmings, n=118). Vidas ECO detected 451 (12%) samples positive, but from only 27 (0.74%) samples was E. coli O157 isolated. One strain was isolated from bovine ground beef (0.18%), one from a pig carcass (1.17%) and all others were isolated from bovine carcasses (1.02%). All strains possessed the attaching-and-effacing gene, the enterohemorrhagic plasmid and verotoxin (VT) genes, except the strain isolated from the pig carcass that was therefore eliminated. Six of the strains were urease-positive. Strains were typed by two DNA fingerprinting methods: random amplification of polymorphic DNA (RAPD) and pulsed field gel electrophoresis (PFGE). PFGE revealed a similarity of 71.05%, while RAPD was 77.36% similar. None of the typing methods were able to classify all urease-positive strains to one pattern. Strains in the same PFGE cluster did not belong to one RAPD cluster. This paper highlights that Belgian fresh meat at retail level can be contaminated with E. coli O157 and that two different typing methods divide strains into different types.

Abattoirs↗
PubMed2002

Isolation and characterization of enterohaemorrhagic Escherichia coli O157:1H7 from cattle in Belgium and Poland.

EHEC O157 were isolated from faeces of Belgian and Polish beef slaughter cattle. In Belgium, 1281 faecal samples were analysed by immunomagnetic separation [IMS] after enrichment in buffered peptone water from June 1998 till July 1999. Eighty-one samples (6.3%) were positive for E. coli O157. Phage type 8 was most frequently found. Bulls between 1 and 2 years old, slaughtered in September and October were most frequently found positive. Atypical biochemical features were observed in some isolates: 22 (27%) isolates were urease positive and 1 (1.2%) isolate was unable to ferment lactose. In Poland, 551 faecal samples, taken from January 1999 till December 1999, were examined using exactly the same techniques. Four faecal samples (0.7%) were positive for O157 EHEC, yielding seven phage type 8 isolates. All positive samples were from cattle younger than 2 years. Positive samples occurred in August, September and October.

Animals↗
PubMed2001

Particular biochemical profiles for enterohemorrhagic Escherichia coli O157:H7 isolates on the ID 32E system.

The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates among 106 E. coli non-O157 isolates was evaluated. The results showed atypical biochemical reactions but accurate identification at the species level and no unique biochemical profile numbers for E. coli O157, although these numbers were distinct from those of other serotypes.

Bacterial Typing Techniques↗
PubMed2001

Effect of acid resistance of Escherichia coli O157:H7 on efficacy of buffered lactic acid to decontaminate chilled beef tissue and effect of modified atmosphere packaging on survival of Escherichia coli O157:H7 on red meat.

The present study examined the effect of pH-independent acid resistance of Escherichia coli O157:H7 on efficacy of buffered lactic acid to decontaminate chilled beef tissue. A varied level of acid resistance was observed among the 14 strains tested. Eight strains were categorized as acid resistant, four strains as acid sensitive, and two strains demonstrated acid-inducible acid resistance. The survival of an acid-resistant (II/45/4) and acid-sensitive (IX/8/16) E. coli O157:H7 strain on chilled beef tissue treated with 1 and 2% buffered lactic acid, sterile water, or no treatment (control) was followed. A gradual reduction of E. coli O157:H7 was noticed during the 10 days of storage at 4 degrees C for each of the treatments. Decontamination with 1 and 2% buffered lactic acid did not appreciably affect the pathogen. Differences in the pH-independent acid resistance of the strains had no effect on the efficacy of decontamination. The effect of modified atmosphere packaging (MAP) on survival of E. coli O157:H7 in red meat was also studied. MAP (40% CO2/60% N2) or vacuum did not significantly influence survival of E. coli O157:H7 on inoculated sliced beef (retail cuts) meat compared to packing in air. The relative small outgrowth of lactic acid bacteria during storage under vacuum for 28 days did not affect survival of E. coli O157:H7. Neither lactic acid decontamination nor vacuum or MAP packaging could enhance reduction of E. coli O157:H7 on beef, thus underlining the need for preventive measures to control the public health risk of E. coli O157:H7.

Adaptation, Physiological↗
PubMed2000

Microbiology of the middle meatus: a comparison between normal adults and children.

Middle meatal samples were obtained from 52 carefully selected healthy adults. In 75 per cent of the test subjects bacterial organisms were cultured. However, growth was often poor and the predominant species suggest a commensal flora: coagulase-negative staphylococci were retrieved from 35 per cent, Corynebacterium sp. from 23 per cent and Staphyloccus aureus from eight per cent of the adults. These data are very different from those previously obtained among children where--even in the absence of obvious ENT pathology--the most frequently cultured organisms were typical sinusitis pathogens: Haemophilus influenzae present in 40 per cent, Moraxella catarrhalis in 34 per cent and Streptococcus pneumoniae in 50 per cent of children. Furthermore, Streptococcus viridans and Neisseria sp., both organisms that might be able to inhibit colonization by some of the pathogens and found commonly among children, are virtually absent in healthy adults.

Acute Disease↗
PubMed1999

Bacteriology of the middle meatus in children.

Little is known about the bacteriology of the middle meatus in children. Therefore, middle meatal samples were obtained from 50 children who underwent adenoidectomy or adenotonsillectomy, while a group of 50 children submitted to minor non-ENT surgical procedures, were used as a control group. Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae were the most frequent cultured organisms, not only in the ENT group (in 68, 50 and 60% of the children respectively) but also in the control group (40, 34 and 50%). These three potential pathogens were more frequently seen among the children of the ENT group but only for H. influenzae was the observed difference statistically significant (P = 0.009). On semiquantitative analysis, there seemed to be more negative cultures or cultures with only a few colonies in the control group, while the richer cultures were obtained from the ENT group. Again, only for H. influenzae, these differences reached a statistical significance (P = 0.003). Streptococcus viridans and Neisseria species, both organisms that might be able to inhibit colonisation by some of the pathogens, were more frequently cultured in the control than in the ENT group: Strep. viridans 30 vs. 10% (P = 0.025) and Neisseria species 14 vs. 2% (P = 0.069).

Child, Preschool↗
PubMed1999

Microbiology of the middle meatus in children requiring adenotonsillectomy.

Middle meatus samples were cultured in 120 children undergoing adenotonsillectomy with, or without, insertion of ventilation tubes. Every child (except one) had positive cultures. Haemophilus influenzae (62 per cent of the children), Moraxella catarrhalis (53 per cent) and Streptococcus pneumoniae (48 per cent) were the most commonly isolated bacteria. The presence of Moraxella catarrhalis and (to a lesser extent) Streptococcus pneumoniae was higher in younger children, while Haemophilus influenzae was cultured independently of age. Culture results of these middle meatal samples, carefully taken in order to avoid any contamination, probably reflect some ongoing sinus infection in these children requiring adenotonsillectomy. The problems inherent in the interpretation of surface cultures are addressed.

Adenoidectomy↗
PubMed1998

Neonatal infections with Pseudomonas aeruginosa associated with a water-bath used to thaw fresh frozen plasma.

In our 15-bed neonatal intensive care unit (NICU), four new-borns were found to be colonized or infected with Pseudomonas aeruginosa within a period of one week. To identify the outbreak source, three independent studies were performed: epidemiological investigation, environmental surveillance and genotypic typing of isolates. Although epidemiological investigation by a case-control study revealed no conclusive results, the transfusion of fresh frozen plasma (FFP) and human albumin (HA) appeared to be the factor with highest risk. Environmental surveillance and random amplification of polymorphic DNA (RAPD) of isolates identified a water-bath used to warm FFP and HA as the likely reservoir for the outbreak. Further spread of the organism did not occur after elimination of this water-bath from the NICU. RAPD identified in addition an isolate from an infant hospitalized in the NICU five months before the outbreak with a pattern matching the one of the outbreak cluster.

Belgium↗
PubMed1998

Association of enterohemorrhagic Escherichia coli hemolysin with serotypes of shiga-like-toxin-producing Escherichia coli of human and bovine origins.

In this study we investigated whether the enterohemorrhagic Escherichia coli (EHEC) hemolysin gene ehxA could be used as an indicator of pathogenicity in Shiga-like-toxin-producing Escherichia coli (SLTEC) isolates. The isolates in a collection of 770 SLTEC strains of human and bovine origins were assigned to group 1 (230 human and 138 bovine SLTEC isolates belonging to serotypes frequently implicated in human disease), group 2 (85 human and 183 bovine isolates belonging to serotypes less frequently implicated in disease), and group 3 (134 bovine isolates belonging to serotypes not implicated in disease). PCR amplification was used to examine all of the SLTEC isolates for the presence of ehxA and the virulence-associated genes eae, slt-I, and slt-II. The percentages of human isolates in groups 1 and 2 that were positive for ehxA were 89 and 46%, respectively, and the percentages of bovine isolates in groups 1 to 3 that were positive for ehxA were 89, 51, and 52%, respectively. The percentages of human isolates in groups 1 and 2 that were positive for eae were 92 and 27%, respectively, and the percentages of bovine isolates in groups 1 to 3 that were positive for eae were 78, 15, and 19%, respectively. The frequencies of both ehxA and eae were significantly higher for group 1 isolates than for group 2 isolates. The presence of the ehxA gene was associated with serotype, as was the presence of the eae gene. Some serotypes, such as O117:H4, lacked both eae and ehxA and have been associated with severe disease, but only infrequently. The slt-I genes were more frequent in group 1 isolates than in group 2 isolates, and the slt-II genes were more frequent in group 2 isolates than in group 1 isolates. In a second experiment we determined the occurrence of the ehxA and slt genes in E. coli isolated from bovine feces. Fecal samples from 175 animals were streaked onto washed sheep erythrocyte agar plates. Eight E. coli-like colonies representing all of the morphological types were transferred to MacConkey agar. A total of 1, 080 E. coli isolates were examined, and the ehxA gene was detected in 12 independent strains, only 3 of which were positive for slt. We concluded that the ehxA gene was less correlated with virulence than the eae gene was and that EHEC hemolysin alone has limited value for screening bovine feces for pathogenic SLTEC because of presence of the ehxA gene in bovine isolates that are not SLTEC.

Animals↗
PubMed1998

Severe encephalopathy in a child: an uncommon cause.

Cat scratch disease (CSD) is usually a self-limited disease. Although extremely uncommon, the involvement of the central nervous system has been previously reported in CSD. The intention of this paper is to make physicians aware that CSD could be complicated by encephalopathy. Seizures in some patients could be the only clinical manifestation and are resistant to the common anti-epileptic therapy. The seizures resolve with supportive care.

Acute Disease↗
PubMed1997

Prevalence of hepatitis A, B and C in the Flemish population.

Viral hepatitis is a serious health problem throughout the world. No recent prevalence data on hepatitis A, B and C were available for the population in Flanders, Belgium. For this reason, a sero-epidemiological study was undertaken in 1993-1994 in a sample of the general population. The purpose of this study was to obtain a clear picture of the prevalence of hepatitis A, B and C. Between April 1993 and February 1994, 4,058 blood samples were drawn and collected in 10 hospitals in Flanders. The study group was representative for the Flemish population. For hepatitis A a seroprevalence of 55.1% was found. In the non-Belgian residents the HAV prevalence was significantly higher than in Belgians (62% versus 52%; chi2 = 8.05; p = 0.005). For hepatitis B. 9.9% of the study group showed serological evidence of hepatitis B markers: 6.9% of the participants was positive for anti-HBs/anti-HBc, 0.7% appeared to be HBsAg positive and 3.5% was solely anti-HBs positive. The prevalence of HBV markers in Belgians was 6.9%, significantly lower compared to the 13.4% among non-Belgians (chi 2 = 14.05; p = 0.00018). 4055 serum samples were analysed for hepatitis C serology by second generation anti-HCV tests. Anti-HCV was detected in 0.87% of the serum samples. No statistically significant difference was found in HCV prevalnece between Belgians and non-Belgians. Results of this study should help policy makers in their decisions on the most appropriate hepatitis A and B vaccination strategy and on the most effective prevention strategy for hepatitis C.

Adolescent↗
PubMed1997

Microsurgical epididymal sperm aspiration with motile trophozoite cells but no spermatozoa.

This paper reports on a patient in whom the clinical diagnosis of obstructive azoospermia was made according to clinical observations, i.e. azoospermia, normal andrological examination, normal follicle stimulating hormone and a misleading histopathological report of a testicular biopsy. Microsurgical vasoepididymostomy failed to restore fertility, and as a last resort, microsurgical sperm aspiration was performed. Although flagellated cells were observed in the epididymal aspiration, no spermatozoa were observed and wet preparation of multiple testicular biopsies failed to demonstrate any spermatozoon. This patient was diagnosed to have a non-obstructive azoospermia, resulting from maturation arrest associated with trichomonas infection at the level of the epididymis.

Adult↗
PubMed1997

Splenic abscess with Clostridium novyi bacteraemia and sepsis.

Splenic abscess is an uncommon entity and usually results in the death of the patient when left undiagnosed. A case is presented where bacteraemia with an anaerobic Gram-positive bacillus was associated with splenic abscess. Despite treatment with splenectomy and antibiotics the patient developed a multiple organ dysfunction syndrome (MODS) and died. Of particular interest was the isolation of Clostridium novyi type A from the blood in a patient without gas gangrene but with splenic suppuration.

Abdominal Abscess↗
PubMed1996

In vitro activity of amoxycillin/clavulanate and ticarcillin/clavulanate compared with that of other antibiotics against anaerobic bacteria: comparison with the results of the 1987 survey.

The activity of amoxycillin/clavulanate (Augmentin) and ticarcillin/ clavulanate (Timentin) was tested against 351 strict anaerobic clinical isolates collected from September 1993 to April 1994 in eight Belgian university hospitals and compared with that of 8 other antibiotics using the NCCLS reference agar dilution procedure. Production of beta-lactamase was detected by the nitrocefin test in 48% of the isolates. At NCCLS-recommended breakpoints, more than 90% of isolates were susceptible to amoxycillin/clavulanate, ticarcillin/clavulanate, piperacillin/tazobactam, imipenem, chloramphenicol and metronidazole but only 77%, 72% and 48% to cefoxitin, clindamycin and penicillin, respectively. In comparison with the results of a similar survey conducted in 1987 no major changes in susceptibility were observed except for the susceptibility to clindamycin that declined from 83% to 72% overall, and from 83% to 66% in the B. fragilis group. Furthermore one isolate of Clostridium clostridioforme was found produce beta-lactamase and few B. fragilis group isolates showed reduced susceptibility to metronidazole.

Amoxicillin↗