Transitioning from development to commercial: risk-based guidance for critical materials management in cell therapies

A key hurdle to ensuring patient access to cell and gene therapies (CGTs) and continued growth of the industry is the management of raw materials. The combination of rapid growth, individual product and process complexity and limited industry-specific guidance or awareness presents non-obvious risk mitigation challenges for transitioning from development to clinical application. Understanding, assessing and mitigating the varied raw material risks for CGT products during product and clinical development are critical for ensuring smooth transitions into commercialization and for preventing interruption of product supply to patients. This article presents a risk-based approach driven by concerns for patient safety that can help focus and coordinate efforts to address the most critical risk factors. Highlighted are some of the highest risk materials common to the manufacture of many CGTs, including the primary starting material, culture media, reagents and single-use components. Using a hypothetical gene-edited cell therapy as an example, we describe the general manufacturing process and subsequently incorporate the described methodology to perform a sample risk assessment. The practical approach described herein is intended to assist CGT manufacturers and suppliers in actively assessing materials early in development to provide a basic starting point for mitigating risks experienced when translating CGT products for clinical and long-term commercial application.

[Outcome of kidney transplantation in patients on peritoneal dialysis]

The initial experience suggested that kidney transplantation could be hazardous for patients on peritoneal dialysis due to the high risk of peritonitis and a possible high incidence of acute rejection. In this paper we have presented our experience with kidney transplantation in these patients. During the last four years kidney transplantation was performed in 9 patients on peritoneal dialysis. The average time spent on peritoneal dialysis was 20.6 +/- 7.6 months. In all patients peritoneal catheter was removed during the surgery. During the posttransplantation period a triple immunosuppressive therapy including steroids, cyclosporin and azathioprineor mycophenolate mofetil was administered in all patients. In comparison to patients on hemodialysis no significant difference in the incidence of acute rejection episodes, delayed graft function, graft arterial thrombosis and graft function recovery was observed. Patients on peritoneal dialysis had significantly greater and longer wound drainage in comparison to patients on hemodialysis. It was concluded that peritoneal dialysis had no negative influence on short-term outcome of kidney transplantation.

In vivo labeling of endothelin receptors with [(11)C]L-753,037: studies in mice and a dog

Endothelin (ET) is a potent mammalian vasoconstrictive peptide and a pressor agent. Its 3 isoforms, ET-1, ET-2, and ET-3, mediate several physiologic actions in several organ systems, binding to 2 major receptor subtypes: ET(A) and ET(B). This study was undertaken to evaluate [(11)C]L-753,037 [(+)-(5S,6R,7R)-2-butyl-7-[2-((2S)-2-carboxy-propyl)-4-methoxyphenyl]-5-(3,4-methylenedioxyphenyl)cyclopenteno [1,2-beta]pyridine-6-carboxylate), a new mixed ET receptor A and B antagonist, as a tracer for in vivo labeling of ET receptors in mice and a dog.

METHODS

[(11)C]L-753,037 was synthesized, purified, and formulated from a normethyl precursor, L-843,974, and [(11)C]H(3)I. The tracer was studied for its in vivo kinetics, biodistribution, and ET receptor binding characteristics in mice. In the dog, PET imaging was performed to evaluate binding of [(11)C]L-753,037 to ET receptors in the heart. Specificity of binding was studied in the heart with the selective ET(A) antagonist L-753,164.

RESULTS

Kinetic studies in mice showed highest tracer uptake at 5 min after injection in liver (25.0 percentage injected dose per gram [%ID/g]), kidneys (18.7 %ID/g), lungs (15.2 %ID/g), and heart (5.6 %ID/g). Initial high uptake in liver, lungs, and kidneys was followed by rapid washout during the next 10 min and a very slow clearance during the time of observation (2 h after injection). By contrast, the radioactivity in the heart remained constant over 2 h. Administration of both ET(A) (L-753,164) and mixed ET(A)/ET(B) (L-753,137) receptor antagonists resulted in dose-dependent inhibition of [(11)C]L-753,037 binding in mouse heart, lungs, and kidneys but not in the liver. Radioactivity in the brain was very low, indicating that the tracer does not cross the blood-brain barrier. In the dog, a dynamic PET study of the heart showed high tracer accumulation at 55-95 min after injection. Injection of L-753,164 at 30 min before [(11)C]L-753,037 administration led to a significant reduction in tracer binding. [(11)C]methyl triphenyl phosphonium was used as a tracer for reference images of the dog heart muscle.

CONCLUSION

The results suggest that [(11)C]L-753,037 binds to ET receptors in vivo and is, therefore, a promising candidate for investigation of these receptors and their occupancy by ET receptor antagonists using PET.

[Peritoneal dialysis and kidney transplantation]

The results of pretransplantation preparation of patients undergoing peritoneal dialysis program before the kidney transplantation at our clinic have been presented. Residual kidney function, and bladder function, respectively, as well as the incidence of the hepatotropic viruses B and C infections and cytotoxic antibodies percentage following blood transfusion have been particularly analyzed. Obtained results have been correlated with those found in 40 patients on hemodialysis and to whom kidneys were transplanted at our clinic. Satisfactory bladder function, the absence of urologic posttransplantation complications, non-existence of hepatotropic viral infections and cytotoxic antibodies resulted in an introduction of a new strategy based on the peritoneal dialysis as the first method of the dialysis treatment prior to kidney transplantation.

A highly specific one-step PCR - assay for the rapid discrimination of enteropathogenic Yersinia enterocolitica from pathogenic Yersinia pseudotuberculosis and Yersinia pestis

Based on differences within the yopT-coding region of Yersinia. enterocolitica, Y pseudotuberculosis and Y pestis, a rapid and sensitive one-step polymerase chain reaction assay with high specificity for pathogenic Y enterocolitica was developed. By this method pathogenic isolates of Y enterocolitica can be easily identified and discriminated from other members of this genus. The entire coding sequence of the yopT effector gene of Y. pseudotuberculosis Y36 was determined.

Specific detection of plasmid bearing Yersinia isolates by PCR

A total of 210 isolates belonging to 9 different species of the genus Yersinia (Y.) was investigated with three different PCR assays targeting two plasmoidal genes, the Yersinia adhesin gene (yadA) and the V-antigen gene. The yadA PCR assay described in 1995 by Blais and Phillipe, targeting a Y. enterocolitica specific gene region and a newly designed assay targeting the gene region functionally responsible for autoagglutination, were compared. Both assays identified the same Y. enterocolitica strains. To exclude the possibility that false negative results were obtained due to mutations that had occurred in parallel in both gene regions, a third PCR assay by Neubauer et al. (2000) targeting a conserved region of the V-antigen gene was used as control. Again, DNA of the same Y. enterocolitica strains was amplified. In contrast to the yadA PCR assay described by Blais and Phillipe, the newly established yadA and the V-antigen PCR assays amplified DNA from Y. pseudotuberculosis strains. Therefore, by using the PCR technique as a molecular tool spontaneous mutations could be excluded as the cause of anomalous reactions in PCR assays targeting genes of the Yersinia virulence plasmid. Based on these results, it can be assumed that all presumptive pathogenic Yersinia isolates can be identified on the basis of PCR analysis. These molecular assays may also produce fewer false positive reactions in comparison to phenotypic tests such as the autoagglutination test which depend heavily on the handler's experience. It has to be stressed that the PCR assays used in this study have not been evaluated for routine use. Therefore, standardization of the PCR methodology including sample preparation, primer target sequences and PCR reagents is needed for the reliable and safe diagnosis of pathogenic Yersinia spp. in future.

A miniaturised semiautomated system for the identification of Yersinia species within the genus Yersinia

Commercially available identification systems based on biochemical reactions of bacteria are not suited for typing the species of the genus Yersinia (Y.) or the biovars (BV) of the species Y. enterocolitica. This failure is caused by the limited number of biochemical reactions applied, resulting in the absence of important discriminatory key reactions. The MICRONAUT identification system (Merlin, Bornheim-Hersel) makes use of dried substrates/enzymes reactions in the wells of a 96-well microtitration plate, reading of the results by a scanner device and typing of the isolate by the calculation of probabilities according to a data base. For this study a special identification panel was designed on which 38 substrates and enzyme reactions were configurated including 20 reactions for the identification of the species of the genus and the Y. enterocolitica biovars. The database was calculated using the results obtained from a total of 250 Yersinia strains of the eleven species of the genus. Reevaluation of the results of these strains revealed an overall sensitivity of 98%, as only four strains were not identified satisfactorily. Considering also questionable results the sensitivity was still 85%. The system was also used to identify Y. pestis isolates, but in this case reading was done visually. The printouts usually cite species designation, identification quality and probabilities. The sealing of the plates in an aluminium bag guarantees long life and long lasting quality. However, an evaluation of the system with a considerable number of strains has to be done in a next step. The 'Yersinia identification set' can replace time-consuming tube testing in the future and is a big step forward towards a sensitive identification of Yersinia isolates in the routine laboratory.

Serodiagnosis of human plague by an anti-F1 capsular antigen specific IgG/IgM ELISA and immunoblot

Plague is a re-emerging disease endemic in at least 24 countries. Non-endemic countries should be able to confirm plague to prevent outbreaks due to imported cases. We established a combination of a IgG/IgM screening ELISA and a confirmation immunoblot employing F1 capsular antigen (CA) for the serodiagnosis of plague in countries where yersiniosis is present. The ELISA and the immunoblot assay showed a specificity of 96.1% and 100% among sera from healthy German blood donors. This group had a seroprevalence of 39% of anti-yersinia outer protein (YOP) antibodies obviously caused by previous Y. enterocolitica infection. The ELISA detected anti-F1 CA antibodies in 22 and the immunoblot in 20 out of 26 sera of plague vaccinees. Five control sera from bacteriologically confirmed plague cases from Madagascar reacted positively. It can be concluded that anti-YOP antibodies do not affect assays based on purified F1 CA.

A combination of different polymerase chain reaction (PCR) assays for the presumptive identification of Yersinia pestis

A combination of four polymerase chain reaction (PCR) assays targeting the Yersinia pestis-specific plasmoidal genes of the fraction 1 capsular antigen and plasminogen activator/coagulase, the gene of the V antigen of the Yersinia virulence plasmid, and the chromosomal 16S rRNA gene was evaluated for the identification of Y. pestis isolates. All four assays were subjected to the same sample preparation technique, reagents and cycling conditions. Eighteen Y. pestis, 66 Y. pseudotuberculosis, 40 Y. enterocolitica strains, the type strains of the other Yersinia species, and 20 other pathogenic bacterial strains were investigated. By using the proposed combination of PCR assays all Y. pestis strains were identified correctly. The applicability of this combination of PCR assays was demonstrated by the detection of Y. pestis DNA in spiked tissues from Rattus norwegicus and fleas (Xenopsylla cheopis and Ctenocephalides spp.). As little as 60 genome equivalents were detected. This system is applicable for monitoring Y. pestis and its vectors in enzootic natural foci and in the diagnosis of plague in humans and animals.

Clonal diversity of Shiga toxin-producing Escherichia coli O157:H7/H- in Germany--a ten-year study

Two hundred and ten E. coli O157:H7/H- strains isolated from single cases and outbreaks of diarrhoea and haemolytic uraemic syndrome (HUS) in Germany between 1988 and 1998 were characterised by a range of molecular subtyping methods and phage typing in order to analyse their clonal nature. A high clonal heterogeneity, together with a considerable clonal stability, has been identified among the bacterial isolates and no single clonal type appeared to be geographically dominant. It is recommended to apply pulsed-field gel electrophoresis (PFGE) together with P gene profile determination (number and genomic positions of lambdoid bacteriophages) as laboratory tools for an extended epidemiological surveillance of E. coli OOFF phage typing will remain helpful as a first line of analysis, particularly in outbreak situations.

Evaluation of a Yersinia adhesion gene (yadA) specific PCR for the identification of enteropathogenic Yersinia enterocolitica

A total of 101 Yersinia enterocolitica strains was investigated with a PCR assay [Blais and Phillipe, Food Control, 6 (1995) 211-214] targeting the Yersinia adhesin gene (yadA) responsible for autoagglutination. Compared to the autoagglutination test the PCR assay has a specificity of 100% but a sensitivity of only 70%. This failure might be caused by the sequence heterogeneity of yadA.

Identification of Yersinia enterocolitica within the genus Yersinia

In this report we describe a PCR strategy for the unambigous identification of biochemically presumptive typed Yersinia (Y.) enterocolitica. A total of 269 isolates belonging to ten species of the genus Yersinia were investigated. In a first PCR only isolates classified as Y. enterocolitica (n = 113) gave rise to a specific amplification resulting in a sensitivity and a specificity of 100%. By sequencing the 269 amplicons of a second pan-Yersinia PCR spanning a distinct 16S rRNA gene region, 20 different sequence clusters could be identified within the genus. By this, Y. enterocolitica isolates of American and European origin could be distinguished safely and already described sequence clusters of the species Y. frederiksenii were confirmed. New 16S rRNA gene sequence clusters were detected for the species Y. frederiksenii, Y. intermedia, Y. mollaretii, Y. aldovae, Y. kristensenii, and Y. rohdei.

Yersinia enterocolitica 16S rRNA gene types belong to the same genospecies but form three homology groups

The species Yersinia (Y.) enterocolitica consists of biochemically and serologically heterogeneous strains. A vernacular nomenclature divides these strains in 'European' and 'American' bioserotypes. We investigated six strains of each group by DNA-DNA hybridization, determination of G + C mol% content and sequence alignment studies. Based on different DNA-DNA hybridization values and the 16S rRNA gene sequences a division into two Yersinia enterocolitica subspecies is justified. We propose the names Yersinia enterocolitica subsp. enterocolitica for strains belonging to the 16S rRNA gene type represented by the Type strain ATCC 9610 and Yersinia enterocolitica subsp. palearctica for strains belonging to the 16S rRNA gene type of strain Y11 (DSMZ13030).

SPECT brain perfusion findings in mild or moderate traumatic brain injury

BACKGROUND

The purpose of this manuscript is to present the findings in the largest series of SPECT brain perfusion imaging reported to date for mild or moderate traumatic brain injury.

PATIENTS AND METHODS

This is a retrospective evaluation of 228 SPECT brain perfusion-imaging studies of patients who suffered mild or moderate traumatic brain injury with or without loss of consciousness (LOC). All patients had no past medical history of previous brain trauma, neurological, or psychiatric diseases, HIV, alcohol or drug abuse. The patient population included 135 males and 93 females. The ages ranged from 11-88 years (mean 40.8). The most common complaints were characteristic of the postconcussion syndrome: headaches 139/228 (61%); dizziness 61/228 (27%); and memory problems 63/228 (28%). LOC status was reported to be positive in 121/228 (53%), negative in 41/228 (18%), and unknown for 63/228 (28%).

RESULTS

Normal studies accounted for 52/228 (23%). For abnormal studies (176/228 or 77%) the findings were as follows: basal ganglia hypoperfusion 338 lesions (55.2%); frontal lobe hypoperfusion 146 (23.8%); temporal lobes hypoperfusion 80 (13%); parietal lobes hypoperfusion 20 (3.7%); insular and or occipital lobes hypoperfusion 28 (4.6%). Patients' symptoms correlated with the SPECT brain perfusion findings. The SPECT BPI studies in 122/228 (54%) were done early within 3 months of the date of the accident, and for the remainder, 106/228 (46%) over 3 months and less than 3 years from the date of the injury. In early imaging, 382 lesions were detected; in 92 patients (average 4.2 lesions per study) imaging after 3 months detected 230 lesions: in 84 patients (average 2.7 lesions per study).

CONCLUSIONS

Basal ganglia hypoperfusion is the most common abnormality following mild or moderate traumatic brain injury (p = 0.006), and is more common in patients complaining of memory problem (p = 0.0005) and dizziness (p = 0.003). Early imaging can detect more lesions than delayed imaging (p = 0.0011). SPECT brain perfusion abnormalities can occur in the absence of LOC.

Detection of antibodies against Campylobacter jejuni serogroup PEN O:19 purified flagellar protein in a patient with Guillain-Barré syndrome

C. jejuni serogroup PEN O:19 was isolated from a stool specimen from a patient with Guillain-Barré syndrome (GBS). Flagellar protein was isolated and purified from reference strain C. jejuni PEN O:19, ATCC 43,446, as well as from a homologous patient strain. Antibodies against flagellar protein were detected by means of immunoblotting, enzyme-linked immunosorbent assay (ELISA) and tube agglutination test. The antibody titres were found to be directly correlated at the beginning and in the recovery phase of GBS. Antibodies of IgG and IgA classes were present from the very onset of the disease as well as 5 months later, but with a lower titre population. However, antibodies of the IgM class were persistent only at the onset of the infection and disappeared during the following 5 months. Our results strongly support the hypothesis that in GBS patients, antiflagellar antibodies are induced during C. jejuni infection and can be used in the diagnosis of C. jejuni-associated GBS.

Variations in the 16S rRNA gene sequence of Yersinia enterocolitica isolates influence the specificity of molecular identification systems

Four identification systems were used to type Yersinia enterocolitica strain Y11 and Yersinia enterocolitica sensu strictoT. Two systems based on biochemical reaction patterns identified both strains as Yersinia enterocolitica. Two molecular assays targeting the 16S rRNA gene failed to identify either strain Y11 or the type strain. Therefore, both strains were typed by the classical taxonomical approach requiring a determination of the overall base composition and the base sequence similarity using hybridization. Again both strains were classified as Yersinia enterocolitica isolates. Consequently, the sequences of the 16S rRNA gene of both strains were determined and compared. The strains differed in a region where nucleotide changes between species of the genus Yersinia had been described earlier. These differences may explain the failure of the molecular assays to identify the strains. They also demonstrate an independent evolution of the 16S rRNA genes in the species Yersinia enterocolitica sensu stricto suggesting an amendment to the nomenclature to be used in the future.

SPET brain perfusion imaging in mild traumatic brain injury without loss of consciousness and normal computed tomography

We present SPET brain perfusion findings in 32 patients who suffered mild traumatic brain injury without loss of consciousness and normal computed tomography. None of the patients had previous traumatic brain injury, CVA, HIV, psychiatric disorders or a history of alcohol or drug abuse. Their ages ranged from 11 to 61 years (mean = 42). The study was performed in 20 patients (62%) within 3 months of the date of injury and in 12 (38%) patients more than 3 months post-injury. Nineteen patients (60%) were involved in a motor vehicle accident, 10 patients (31%) sustained a fall and three patients (9%) received a blow to the head. The most common complaints were headaches in 26 patients (81%), memory deficits in 15 (47%), dizziness in 13 (41%) and sleep disorders in eight (25%). The studies were acquired approximately 2 h after an intravenous injection of 740 MBq (20.0 mCi) of 99Tcm-HMPAO. All images were acquired on a triple-headed gamma camera. The data were displayed on a 10-grade colour scale, with 2-pixel thickness (7.4 mm), and were reviewed blind to the patient's history of symptoms. The cerebellum was used as the reference site (100% maximum value). Any decrease in cerebral perfusion in the cortex or basal ganglia less than 70%, or less than 50% in the medial temporal lobe, compared to the cerebellar reference was considered abnormal. The results show that 13 (41%) had normal studies and 19 (59%) were abnormal (13 studies performed within 3 months of the date of injury and six studies performed more than 3 months post-injury). Analysis of the abnormal studies revealed that 17 showed 48 focal lesions and two showed diffuse supratentorial hypoperfusion (one from each of the early and delayed imaging groups). The 12 abnormal studies performed early had 37 focal lesions and averaged 3.1 lesions per patient, whereas there was a reduction to--an average of 2.2 lesions per patient in the five studies (total 11 lesions) performed more than 3 months post-injury. In the 17 abnormal studies with focal lesions, the following regions were involved in descending frequency: frontal lobes 58%, basal ganglia and thalami 47%, temporal lobes 26% and parietal lobes 16%. We conclude that: (1) SPET brain perfusion imaging is valuable and sensitive for the evaluation of cerebral perfusion changes following mild traumatic brain injury; (2) these changes can occur without loss of consciousness; (3) SPET brain perfusion imaging is more sensitive than computed tomography in detecting brain lesions; and (4) the changes may explain a neurological component of the patient's symptoms in the absence of morphological abnormalities using other imaging modalities.

Identification of Yersinia species by the Vitek GNI card

The Vitek GNI card was used to identify 212 isolates of 10 Yersinia species. Identification was correct for 96.3% of the isolates (156 of 162) to the genus level and for 57.4% of the isolates (93 of 162) to the species level for Yersinia spp. listed in the Vitek database. We recommend additional identification methods for isolates assigned to the genus Yersinia by the Vitek system.

Comparison of systems for identification and differentiation of species within the genus Yersinia

Of four tested identification systems (API 20E, API Rapid 32 IDE, Micronaut E, and the PCR-based Yersinia enterocolitica Amplification Set), API 20E is still the system of choice for identifying pathogenic Yersinia isolates. It provides the highest sensitivity both at the genus and at the species level and has the best cost-effectiveness correlation.

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.

Genetic variation of Yersinia enterocolitica serotype O:9 strains detected in samples from western and eastern countries

We made use of H-serotyping, ribotyping and restriction endonuclease analysis of virulence plasmid DNA (REAP) to differentiate Yersinia enterocolitica serotype O:9 strains. A close correlation between ribotypes/REAP patterns and the geographical and chronological distribution of serotype O:9 strains was apparent. In European countries, variant clones of serotype O:9 have rapidly increased among humans and swine since the late 1980s.

Detection of hemolysin variants of Shiga toxin-producing Escherichia coli by PCR and culture on vancomycin-cefixime-cefsulodin blood agar

The presence of a hemolysin-encoding gene, elyA or hlyA, from Shiga toxin-producing Escherichia coli (STEC) was detected by PCR in each of 95 strains tested. PCR products of elyA from human STEC isolates of serovars frequently detected in Germany, such as O157:H-, O103:H2, O103:H-, O26:H11, and O26:H-, showed nucleotide sequences identical to previously reported ones for O157:H7 and O111:H- strains. Compared to them, four elyA amplicons derived from human isolates of rare STEC serovars showed identity of about 98% but lacked an AluI restriction site. However, the nucleotide sequence of an amplicon derived from a porcine O138:K81:H- STEC strain was identical to the corresponding region of hlyA, encoding alpha-hemolysin, from E. coli. This hlyA amplicon showed 68% identity with the nucleotide sequence of the corresponding elyA fragment. It differed from the elyA PCR product in restriction fragments generated by AluI, EcoRI, and MluI. Of the 95 representative STEC strains, 88 produced hemolysin on blood agar supplemented with vancomycin (30 mg/liter), cefixime (20 micrograms/liter), and cefsulodin (3 mg/liter) (BVCC). The lowest added numbers of two to six STEC CFU per g of stool or per ml of raw milk were detectable on BVCC plates after seeding of the preenrichment broth, modified tryptic soy broth (mTSB) supplemented with novobiocin (10 mg/liter), with 16 STEC strains. These strains represented the seven prevailing serovars diagnosed from German patients. However, with ground-beef samples, PCR was essential to identify the lowest added numbers of two to six STEC CFU among colonies of hemolyzing Enterobacteriaceae, such as Serratia spp. and alpha-hemolysin-producing E. coli. We conclude that preenrichment of stool and food samples in mTSB for 6 h followed by overnight culturing on BVCC is a simple method for the isolation and presumptive identification of STEC.

Acute and chronic diarrhoea and abdominal colic associated with enteroaggregative Escherichia coli in young children living in western Europe

BACKGROUND

Enteroaggregative Escherichia coli (EAggEC or EAEC) can spread and cause disease in developing countries, but it is not presently known whether it spreads disease in industrialised countries. Therefore, we did a prospective study to assess the incidence and the clinical manifestations of infections due to EAEC in children in Germany.

METHODS

798 children with diarrhoea, admitted to hospital within a defined geographical area during a 24-month period, were included in the trial. EAEC were cultured from stool specimens, screened by PCR, and identified by colony hybridisation from DNA sequences found on the virulence plasmid. The findings were confirmed by aggregative adherence to HEp-2 cells. Stool samples from 580 children admitted to hospital without diarrhoea were also studied as controls.

FINDINGS

EAEC were found in the stools of 16 (2%) of 798 children with diarrhoea, but in none of 580 children without diarrhoea. Only four of the EAEC-infected children had travelled to developing countries. Most EAEC infections were acquired in the summer months. Infection with EAEC was associated with acute, watery diarrhoea in 12 children, and with chronic diarrhoea of up to 5 months' duration in four. Five children had abdominal colic that lasted for 2-4 weeks as their main symptom. The incidence of EAEC infection was 7.7 patients admitted to hospital per 100,000 children in the general population aged younger than 16 years.

INTERPRETATION

EAEC infection is associated with acute, watery diarrhoea and may be acquired in industrialised countries. Chronic diarrhoea or abdominal colic of unknown aetiology in young children may also be caused by EAEC infection.

Epidemiological relatedness and clonal types of natural populations of Escherichia coli strains producing Shiga toxins in separate populations of cattle and sheep

Two separate animal populations consisting of a herd of cattle (19 animals) and a flock of sheep (25 animals) were investigated for strains of Escherichia coli producing Shiga toxins (STEC) over a time period of 6 months. Thirty-three STEC were isolated from 63.2% of cattle and grouped into 11 serotypes and eight electrophoretic types (ETs) by multilocus enzyme analysis. In sheep, 88% of the animals excreted STEC (n = 67 isolates) belonging to 17 different serotypes and 12 different ETs. STEC from cattle and sheep differed with respect to serotype, and only 4 of the 16 ETs occurred in both animal populations. In cattle, ET14 (O116:H21) strains predominated, whereas other STEC serotypes occurred only sporadically. The predominating STEC types in sheep were ET4 (O125 strains), ET11 (O128:H2 and others), and ET14 (O146:H21). In contrast to their diversity, STEC originating from the same animal population were similar with respect to Shiga toxin (stxy genes. Almost all STEC isolated from cattle were positive for stx2 and stx2c; only one was positive for stx1. In sheep, almost all STEC isolated were positive for stx1 and stx2, whereas stx2c was not found. XbaI-digested DNAs of genetically closely related O146:H21 strains have different restriction profiles which were associated with size alterations in XbaI fragments hybridizing with stx1- and stx2-specific DNA probes. Our results indicate that stx-encoding bacteriophages might be the origin of the genetic heterogeneity in STEC from animals.

Cardiac autonomic nerve function and insulin sensitivity in obese subjects

OBJECTIVE

To investigate whether obesity influences cardiac autonomic nerve function.

DESIGN

Comparing two groups of subjects with different degrees of obesity to normal weight controls.

SUBJECTS

19 healthy controls (mean age 33 y, BMI 21.7 +/- 0.2 kg/m2) and 17 obese non-diabetic subjects (mean age 39 y, BMI 33.7 +/- 1.8 kg/m2).

MEASUREMENTS

Insulin sensitivity was calculated by an oral glucose tolerance test. Autonomic nerve function was evaluated by analysing the variation of the heart frequency at rest (coefficient variation of R-R intervals, REST 1), during deep respiration, at a Valsalva maneuver (longest/shortest R-R interval during inspiration hold) and by the Ewing test (ratio between the 30th and 15th R-R interval after reaching up-right position).

RESULTS

The obese showed a lower insulin sensitivity than healthy controls (3.09 vs 4.60 mg x l2/mmol x mU x min, P < 0.001). Their variation in heart frequency was reduced (REST 1: 1.95 vs 2.9, P < 0.01, Valsalva: 1.30 vs 1.52 and Ewing test: 1.03 vs 1.14, P < 0.05). However, patients with moderate (BMI 31.7 kg/m2) or severe obesity (39.0 kg/m2) with identical insulin sensitivity had no significant difference in autonomic nerve function. Except for the Ewing test all measured parameters for the evaluation of cardiac autonomic nerve function correlated with the degree of diminished insulin sensitivity (REST 1: r = 0.475, P < 0.001).

CONCLUSION

Moderate obesity with significantly decreased insulin sensitivity is associated with impaired cardiac autonomic nerve function.

Campylobacter and Salmonella contaminating fresh chicken meat

1853 packages of fresh chicken breast meat of German, Dutch and French origin were investigated for their contamination with Campylobacter and/or Salmonella. Swabs were taken and cultured from dripwater, meat surface, meat interior and packet bowl. Campylobacter was isolated from 619 meat samples (= 33%), Salmonella from 377 meat packages (= 20%). In 111 of these contaminated chicken samples, both Salmonella and Campylobacter were present. The contamination rate and the species spectrum observed differed depending on the origin of the packages and the time of control.

Prevalence and clinical manifestations of Shiga toxin-producing Escherichia coli infections in Austrian children

The prevalence and clinical manifestations of infections associated with Shiga toxin-producing Escherichia coli (STEC) among Austrian children were assessed. Stool samples from 280 pediatric patients were analyzed by enzyme immunoassay (EIA) for the presence of free fecal Shiga toxin (Stx) 1 and 2, and by culture on sorbitol MacConkey agar. Specimens testing positive by the EIA were subjected to a cytotoxicity assay, polymerase chain reaction analysis, and a colony hybridization test. Direct culture on MacConkey agar demonstrated the presence of three Escherichia coli O157:H7-positive stools. These were also positive by EIA and by the DNA-based methods. An additional six samples were positive by EIA, and in four of these, non-O157 STEC of serotypes O111H-, O146:H-, and O113:H53 could be isolated. Analysis of stools for a variety of enteric pathogens demonstrated that STEC was the third most common bacterial pathogen. The clinical manifestations of STEC infections were difficult to distinguish from those of infections caused by other enteric pathogens, as most patients presented with watery diarrhea. The median age of children with STEC infections was 27.6 months (range, 7 months to 5.75 years); children with Salmonella or Campylobacter infections were younger on average, while those with Rotavirus infections were older. This study demonstrated that although Escherichia coli O157:H7 could be identified with the same sensitivity by both EIA or agar-based methods, the identification of non-O157 STEC strains was enhanced by the use of EIA followed by colony hybridization. Analysis of overnight cultures from 53 STEC isolates revealed that all strains producing Stx1, Stx2, or Stx2c reacted in the EIA. However, culture supernatants from Stx2e-producing Escherichia coli O101 were negative in the EIA. Despite this disadvantage, the EIA is easy to perform and time efficient and can be recommended as a screening test for non-O157 STEC in children with diarrhea.

Diarrhea in young children associated with Escherichia coli non-O157 organisms that produce Shiga-like toxin

OBJECTIVE

To assess the clinical manifestations and incidence of infection associated with Shiga-like toxin-producing Escherichia coli (SLTEC).

STUDY DESIGN

Children with diarrhea within a defined geographic area during a 12-month period were examined for the presence of SLTEC in their stools by polymerase chain reaction with the use of primers that were complementary to sequences of Shiga-like toxins types I and II and to other virulence factors.

RESULTS

There were 13 SLTEC infections among 468 children with diarrhea. Besides Shiga-like toxin sequences, the virulence genes eae and EHEC-hly were found in 10 isolates; these isolates were categorized as enterohemorrhagic E. coli (EHEC). Only 2 of 13 isolates were of the O157 strain. All reported cases occurred in summer (June through September) with the exception of one case in April. The infections were sporadic, and the infected children lived in rural and urban areas. Three infections in children with disabilities were hospital acquired. The majority of children had watery diarrhea, two had bloody diarrhea, and one had mild hemolytic-uremic syndrome. The overall incidence of SLTEC infection was 12.5 hospitalized children per 100,000 children less than 16 years of age.

CONCLUSIONS

The most frequent clinical manifestation of SLTEC infection was watery diarrhea indistinguishable from other forms of infectious diarrhea. The shift from the O157 strain toward non-O157 SLTEC strains associated with diarrhea, also observed in German patients with hemolytic-uremic syndrome, points to a change in the epidemiologic features of SLTEC-associated disease. Testing for non-O157 SLTEC should be considered in children with diarrhea without a recognized cause.

Isolation of enterohemorrhagic Escherichia coli O157 strains from patients with hemolytic-uremic syndrome by using immunomagnetic separation, DNA-based methods, and direct culture

We examined 30 children with classical hemolytic-uremic syndrome (HUS) for the presence of enterohemorrhagic Escherichia coli (EHEC) strains in stool samples and determined the specific immune response to O157 lipopolysaccharide in acute-phase serum samples from these patients. EHEC O157 strains were isolated from stool samples of 18 (60%) of the patients, and non-O157 EHEC strains were isolated from 5 (17%) of the patients. For O157 strain isolation from stools, we introduced a selective enrichment step using O157-specific antibodies attached to paramagnetic particles (immunomagnetic separation [IMS] method). This procedure allowed the detection of O157 strains at 10(2) CFU/g of stool in the presence of 10(7) coliform background flora organisms. By using IMS followed by plating on sorbitol MacConkey (SMAC) agar and cefixime-tellurite SMAC (CT-SMAC) agar, O157 strains were detected in 18 samples, whereas colony hybridization detected a subset of 12 positive samples and direct culture on CT-SMAC or SMAC agar detected only 7. Three of the 18 O157-positive stools were negative by cytotoxicity assay performed with stool filtrates and by direct PCR with DNA extracted from stools. The IMS technique allowed the isolation of O157 strains from 18 of 20 patients with serological evidence for O157 infection. Apart from the increase in sensitivity in O157 detection compared with that of direct culture, the IMS technique also has the advantage of being less labor-intensive and less time-consuming than the molecular methods. IMS can therefore be considered an efficient method for wide-spread use in the detection of O157 strains in clinical microbiology laboratories. However, because a significant number of HUS cases were attributable to non-O157 EHEC serogroups, the use of additional methods besides IMS in the bacteriological diagnosis of HUS is necessary.

Human infection caused by Salmonellae of subspecies II to VI in Germany, 1977-1992

Human infections by Salmonella (S.) are usually caused by S. enterica strains belonging to the subspecies I (subsp.). Strains of subsp. II-VI and S. bongori are mostly isolated from animals or environmental specimens, and they are therefore considered as less pathogenic for humans. Out of 90,201 S. isolates examined at the German National Reference Centre for Enteric Pathogens between 1977 to 1992, 89,798 (99.55%) belonged to S. subsp. I, while 403 (0.45%) of strains belonged to S. subsp. II-VI and S. bongori (formerly called subsp. V). 108 strains belonged to subsp. II, 241 isolates to subsp. IIIa and IIIb (formerly called Arizona), 49 to subsp. IV, 4 to S. bongori and one isolate to subsp. VI. 215 of the 403 isolates (53.4%) were from humans, 101 (25.1%) from reptiles, 52 (12.9%) from various warm-blooded animals, 11 (2.7%) from foodstuffs and 12 (3.0%) from environmental specimens. The origin of 12 (3.0%) strains was unknown. According to the clinical diagnosis reported by the laboratories, intestinal disease was associated with 176 (81.9%) out of 215 strains of human origin. 11 (5.1%) strains had been isolated from extraintestinal infections (sepsis, atypical pneumonia, urinary tract and wound infections), and 28 (13.0%) strains from stool specimens of healthy persons. A slightly higher incidence was observed in children of 0-5 years of age (49 cases; 22.8%). Male persons were twice as often affected than females. The seasonal incidence of infections was highest in October and in February. In 53 cases (24.6%), travel to a foreign country was reported.

Nationwide outbreak of human salmonellosis in Germany due to contaminated paprika and paprika-powdered potato chips

Between April and September 1993, a nationwide outbreak of salmonellosis occurred in Germany which was traced to contaminated paprika and paprika-powdered potato chips. Of the estimated 1000 cases, children below 14 years were principally affected. Levels of 0.04-0.45 organisms per gram were found in the snacks. The infective dose was estimated at 4-45 organisms with an attack rate of 1 in 10,000 exposed persons. The unique feature of the outbreak was the variety of serovars involved. S. saintpaul, S. rubislaw and S. javiana were isolated during the same time period from paprika powder, spice mixtures, snacks and patients. Their clonal identity was confirmed by molecular typing methods. Furthermore, monophasic and non-motile strains of rare salmonella O-groups were isolated from both paprika products and patients. This is the largest documented outbreak due to contaminated spices which proved that even extremely low numbers of salmonellae adapted to the dry state were able to cause illness.

Development of PCR for screening of enteroaggregative Escherichia coli

In this study, we determined the sequence of the EcoRI-PstI fragment of the plasmid pCVD432, also termed the enteroaggregative Escherichia coli (EAggEC) probe. A primer pair complementary to this probe was designed for PCR amplification of a 630-bp region. Comparison of the analysis of the EAggEC probe sequence with those in database libraries revealed no significant similarity to any known bacterial gene. Pure cultures of E. coli cells, as well as mixed cultures from stool specimens, were investigated with the PCR assay, the EAggEC probe test, and the adherence test. Of 50 E. coli strains which demonstrated aggregative adherence to HEp-2 cells, 43 (86%) were positive with the EAggEC PCR. All 43 of these strains reacted with the EAggEC probe. Six EAggEC strains gave negative results by both molecular techniques. In contrast, only 4 of 418 (0.96%) strains representing other categories of diarrheagenic E. coli demonstrated a positive PCR result. The PCR was also successful in screening for the presence of EAggEC in enriched cultures grown from stool specimens. Compared with cell culture assays and colony hybridization, our findings revealed that the PCR assay was more rapid, simple, and highly sensitive and can therefore be recommended as a screening method for EAggEC in the clinical laboratory.

Characterisation of pathogenic Yersinia enterocolitica serogroups by pulsed-field gel electrophoresis of genomic NotI restriction fragments

Enteropathogenic Yersinia enterocolitica is an important cause of human and animal disease. Phenotypic and genotypic characteristics currently used to identify Y. enterocolitica are not necessarily sufficient to differentiate pathogenic from non-pathogenic strains or to analyse the epidemiology of yersiniae at a molecular level. To improve the characterisation of Yersinia isolates, NotI restriction fragment length polymorphisms (RFLPs) of chromosomal DNA of more than 100 clinical, animal and environmental isolates were analysed in pulsed-field gel electrophoresis. Highly conserved RFLP patterns with fragments ranging from 15 to 400 kb were detected within each of 10 Y. enterocolitica serogroups tested. Determination of RFLP types makes it possible to discriminate between isolates of different Y. enterocolitica serogroups and other Yersinia spp. Moreover, NotI restriction endonuclease analysis allows even subtyping of strains belonging to a unique serogroup-biotype. Identification of NotI fragments hybridising with inv- or ail-homologous sequences was used as an additional discriminating marker. The results indicate that NotI RFLP typing can provide a powerful new tool for the differentiation of clinical Y. enterocolitica isolates.

Prevalence of attaching and effacing Escherichia coli in stool samples from patients and controls

Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) have the ability to cause 'attaching and effacing' (AE) lesions; the genes necessary to cause AE in both of these pathogroups have been identified and termed eae. Using colony hybridization, we screened 237 stool samples from patients with diarrhea, and 237 stool samples from age-matched controls for the presence of E. coli carrying eae. Individual colonies harbouring eae could be recovered from 7 (2.9%) of the patient stools, as well as from 6 (2.5%) of the control stools. All these E. coli isolates were positive in the fluorescence actin staining (FAS) test. In addition, all the samples were also probed for Shiga-like toxin (slt) genes and the EPEC adherence factor (EAF) to evaluate whether testing for eae identified all EHEC and class I EPEC. Of the 7 patient samples harbouring E. coli with eae, 4 had E. coli with eae and slt genes, and 2 had E. coli with eae and EAF sequences. In 2 of the 237 patient stools, E. coli which were eae and EAF negative but slt probe positive could be recovered. These 2 E. coli strains were non-reactive in the FAS test. Of the control samples, none of the E. coli strains, including the 6 samples containing eae positive strains, possessed EAF or slt-sequences. In concrete terms, the similar eae incidence found in both E. coli isolates from patients and controls is currently of limited clinical diagnostic value and more importantly, the eae probe could not identify all slt-harbouring E. coli. On the basis of these results, the use of the eae-probe cannot be recommended in preference to the slt probes for the detection of EHEC.

Virulence factors and phenotypical traits of verotoxigenic strains of Escherichia coli isolated from human patients in Germany

Fecal isolates of Escherichia coli which were collected from human patients in different parts of Germany between 1985 and 1992 were examined for production of verotoxins (VT). Among 2165 isolates 54 (2.5%) verotoxigenic E. coli (VTEC) were found. The 54 VTEC belonged to 13 different serotypes, 46 (85.2%) of these were enterohemorrhagic E. coli (EHEC) types as O157:H7, O157:H-, O145:H-, O111:[H8] and O26:[H11]. Of the 54 VTEC 50 (92.6%) hybridized with one or both of the DNA probes specific for VT1 and VT2. The 4 VTEC strains which were negative for VT1 and VT2 differed from all other VTEC by many phenotypical trains such as serotype, production of alpha-hemolysin and absence of EHEC-plasmid and "attaching and effacing" (eae)-specific DNA sequences. In contrast, VTEC which were positive for VT1, VT2 or both were frequently positive for eae sequences (92.0%), EHEC-plasmids (90.0%) and for production of enterohemolysin (88.0%). With enterohemolysin as an epidemiological marker more VTEC strains (81.5%) could be identified than with others such as the absence of beta-glucuronidase activity (61.1%) or non-fermentation of sorbitol (48.1%). Case reports were available for 42 of the 54 VTEC strains. The clinical presentation of 42 cases with VTEC ranged from uncomplicated diarrhea to severe diseases as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). However, bloody diarrhea, HC and HUS were more associated with the O157 group than with other VTEC groups.

[A comparison of BRILA-MUG and lauryl sulfate-MUG bouillon as detection media for total and fecal coliform bacteria in bathing waters in conformity with the Economic Community Guideline 76/160 EWG]

The spectrum of gram-negative rods occurring in surface waters is wide and depending on the season, i.e. the water temperature. The concentration of bacteria is higher in summer than in winter. However, the seasonal difference of the concentration of Enterobacteriaceae is less than that of the Aeromonas spec. and of the non-fermenters. The comparison of yields of total and faecal coliforms determined in samples of surface water by using the brilliant green bile lactose 4-methylumbelliferyl-beta-D-glucuronide (BRI-LA-MUG) broth and the lauryl sulfate-MUG broth, respectively, shows that the BRILA-MUG broth is more sensitive and gives higher yields than the lauryl sulfate-MUG broth. On the other hand, the lauryl sulfate-MUG broth inhibits more the growth of gram-negative rods, especially that of Aeromonas spec. and non-fermenters, whereas the Enterobacteriaceae are less inhibited.

Catheter-related Rahnella aquatilis bacteremia in a pediatric bone marrow transplant recipient

Rahnella aquatilis, a rarely encountered member of the family Enterobacteriaceae, was twice isolated from the blood of a pediatric bone marrow transplant recipient. This is the first report of a pediatric case of R. aquatilis bacteremia, and it was probably related to inappropriate handling of a Hickman catheter.

Characterization of Yersinia pseudotuberculosis serogroups O9, O10 and O11; subdivision of O1 serogroup into O1a, O1b, and O1c subgroups

In this study, three new antigens (O9, O10 and O11) of Yersinia pseudotuberculosis are described. The O1 antigen is further subdivided into O1a, O1b and O1c. The methods used to prepare specific antisera for O-antigen identification are also described. Furthermore, the H antigens of these new serogroups are determined and their biochemical characteristics analysed. The antigenic formulae of the known serogroups within the basic antigenic scheme introduced by the authors' laboratories are presented.

Differentiation of Yersinia enterocolitica serotype O:5,27 strains by phenotypic and molecular techniques

Restriction endonuclease analyses of virulence plasmid DNA (REAP) and chromosomal DNA and other phenotypic characteristics were used to study the differentiation of Yersinia enterocolitica serotype O:5,27 strains. There was a close correlation between REAP patterns and the geographical distribution of serotype O:5,27. Human isolates produced only one REAP pattern, which was also found with isolates from pigs and dogs.

Clonal structure and pathogenicity of Shiga-like toxin-producing, sorbitol-fermenting Escherichia coli O157:H-

We compared a collection of sorbitol-fermenting (SF) Escherichia coli O157:H- strains with SF E. coli O157:H45 and non-SF E. coli O157:H7 and E. coli O157:H- strains by pulsed-field gel electrophoresis. The SF E. coli O157:H- strains had identical or closely related XbaI patterns that differed markedly from those for the other E. coli O157 strains. Plasmid content and the presence of Shiga-like toxin-converting phages were determined for the SF E. coli O157:H- strains, indicating that these strains harbor a single 90-kb plasmid. They are lysogenized by toxin-converting phages and harbor the eae gene. Nonmotile E. coli O157 strains were observed to adhere more efficiently to HEp-2 cells than the motile strains. From their phenotypic and genotypic features, the SF E. coli O157:H- strains may well represent a new clone with non-SF E. coli O157:H7 pathogenic characteristics.

[Growth behavior of Enterobacteriaceae in BRILA-MUG-broth and in different modifications of broth]

Both substances, brilliant green and bile, inhibit the growth of gram-positive bacteria in culture media and selectively enrich gram-negative bacteria. Therefore, the brilliant green-lactose-bile broth (BRILA) and the BRLA broth supplemented with tryptophan and methyl-umbelliferyl-beta-D-glucuronide (BRILA-MUG) contain brilliant green as well as bile. Because BRILA-MUG broth as a selective enrichment and differentiating medium of faecal coliform and total coliform bacteria, E. coli and coliforms, respectively, is recommended for testing samples of surface water according to the EC guidelines for bathing waters (no. 76/160 EWG), the question arose of the optimal combination of components in the BRILA-MUG broth. As the described investigations show, the addition of buffer substances did not improve the culture properties of the BRILA-MUG broth. However, the original BRILA broth was improved by supplementing it with buffer substances such as CaCO3 or Na2HPO4. The same effect of culture improvement was obtained by removing brilliant green. This modification of BRILA broth is practically identic with the well-known MacConkey broth. On the other hand, the modification of omitting bile from the original BRILA broth causes a remarkable impairment of the culture properties lowering bacterial counts per ml by 3-5 log. The observations suggest that brilliant green inhibits both, gram-positive bacteria as well as the gram-negative Enterobacteriaceae. Therefore, it is a selective substance of doubtful usefulness.

Molecular detection of sorbitol-fermenting Escherichia coli O157 in patients with hemolytic-uremic syndrome

Shiga-like toxin-producing Escherichia coli strains of serogroup O157 were identified in 26 of 104 patients with hemolytic-uremic syndrome and in 18 of 668 patients with diarrhea. All strains were identified by colony hybridization with DNA probes complementary to Shiga-like toxin I and Shiga-like toxin II gene sequences and characterized by biochemical tests and serotyping. Seventeen of these 44 patients had E. coli O157 strains which were unusual because they fermented sorbitol within 24 h of incubation and were positive for beta-glucuronidase activity. Culture filtrates of these sorbitol-fermenting strains were highly toxic to Vero cells in culture. Serological tests and DNA analysis performed by restriction endonuclease digestion of B-subunit toxin genes revealed that all 17 isolates produced Shiga-like toxin II. Although by using molecular probes we established a high frequency of sorbitol-fermenting E. coli O157 strains in the patients we examined, further studies on the prevalence of such isolates in other areas of endemic disease are clearly warranted.

Lack of the alpha-1,2-linked N-acetyl-D-glucosamine epitope in the outer core structures of lipopolysaccharides from certain O serogroups and subspecies of Salmonella enterica

A total of 176 strains of Salmonella enterica representing 116 serotypes were tested for the presence of the T6 epitope of the alpha-1,2-linked N-acetyl-D-glucosamine residue by reaction with a murine monoclonal antibody T6 specific for this structure in the Salmonella Ra core lipopolysaccharide (LPS). All 20 serotypes (70 strains) belonging to serogroups A to E were positive for the T6 epitope while 29% of the 96 serotypes (106 strains) belonging to O serogroups F to 67 were negative; 12 serotypes (12 strains) of subspecies IIIb Salmonella were positive for the T6 epitope, but 10 serotypes (11 strains) of subspecies IIIa Salmonella were found to lack this epitope. In T6-positive strains, the epitope was accessible to antibody binding in both the unsubstituted free rough core LPS and in the rough core LPS substituted with a few repeating units of O side chains. The presence or absence of the T6 epitope in Salmonella strains was not affected by culture conditions, the source of the isolate, the age of the culture or the presence of fimbriae antigens.

[Comparative studies of fresh and seawater for the determination of total coliform and fecal coliform bacteria according to the European Economic Community guideline 76/160 (bathing water) by the use of the most-probable-number method with BRILA-MUG broth and differentiation according to the drinking water ordinance]

During the summer season of 1989 about 222 samples of bathing water (Northsea, Baltic Sea and inland waters) were investigated, i.e. 2 times 1998 dilution tubes (1501 positive) were tested. Results with BRILA-MUG and lactose-bouillon were compared and additional 97 samples were tested with one respectively three colonies by confirmative tests. -- The BRILA-MUG one-tube-test (gas, fluorescence and indol) has as expected larger numbers of total coliforms (GC) and faecal coliforms (FC) in comparison with corresponding numbers for E. coli and coliform bacteria according to German law for drinking water (TrinkwV). -- BRILA-MUG and lactose-bouillon with the same identification mode according to "TrinkwV" has corresponding results concerning E. coli and coliform bacteria. -- Following the identification mode according to "TrinkwV" the total coliforms (GC/gas in BRILA-MUG) depending on the origin proved 60-80% as coliform bacteria. Additional API-tests showed that the other bacteria are coliform bacteria too or bacteria which can be considered as indicators for water pollution. -- Faecal coliforms (FC/fluorescence and indol-positive) depending on the origin proved 70-90% as E. coli, if following the identification mode according to "TrinkwV". Using 3 instead of 1 colony per positive dilution tube for identification the positive results increased approximately by 9%. 15% of negative results with the identification mode according to "TrinkwV" proved as E. coli-positive with identification according to API-system, i.e. the corresponding rate of E. coli-positive tubes will therefore be higher than shown above. The BRILA-MUG one-tube-test in connection with the MPN-method can be used successfully to determine the number of total and faecal coliforms according to the EEC-directive for bathing waters. The test needs only a minimum of material and also a minimum of laboratory staff. Differences between this test and other more extensive tests with several biochemical identification steps are negligible. The work load for bathing water tests would not be justified in this case.

Comparison of restriction endonuclease analysis and phenotypic typing methods for differentiation of Yersinia enterocolitica isolates

Restriction endonuclease analysis of chromosomal DNA (REAC) was used to study polymorphism in restriction fragment patterns among Yersinia enterocolitica isolates belonging to serogroups O3, O5,27, O8, O9, O13, and O21. Using the enzyme HaeIII and electrophoresis on thin (0.75-mm) vertical 5% polyacrylamide gels, we were able to distinguish at least 22 DNA fragment patterns among the 72 strains examined. The method showed the greatest discriminatory power with regard to serogroup O8, within which as many as 10 different DNA fragment patterns were detected among the 16 strains examined. Compared with O8, serogroups O3 and O9 were relatively homogeneous with regard to REAC patterns. The discriminatory power of the method was compared with H-antigen typing, biotyping, phage typing, antimicrobial susceptibility typing, and restriction enzyme analysis of the virulence plasmid (REAP), by means of Simpson's index of diversity. The results showed that REAC and REAP constitute an effective supplement or alternative to conventional phenotypic methods for tracing epidemiologically related isolates of Y. enterocolitica. Our finding that human and porcine isolates exhibited the same REAC, REAP, and H-antigen patterns provides additional support for the hypothesis that pigs play an important role in the epidemiology of human Y. enterocolitica infection.