Capsular genotype and lipooligosaccharide locus class distribution in Campylobacter jejuni from young children with diarrhea and asymptomatic carriers in Bangladesh

Campylobacter jejuni-related diarrheal diseases is one of the major health issues among young children (0-59 months old) in low-income countries. Monitoring of the capsular (capsule polysaccharide, CPS) types of virulent C. jejuni strains in regions where the disease is endemic is of great importance for the development of a customized capsule-based multivalent vaccine. Therefore, we aimed to determine the prevalence of CPS genotypes among C. jejuni strains isolated from young children with enteritis (n = 152) and asymptomatic carriers matched by age, sex, and residence defined as the control group (n = 215) in Bangladesh. CPS genotyping was performed using a newly established multiplex polymerase chain reaction (PCR) method and lipooligosaccharide (LOS) locus classes (A-E) were characterized using PCR as well. We identified 24 different CPS genotypes among the 367 isolates. Four prevalent capsular types, HS5/31 complex (n = 27, 18%), HS3 (n = 26, 17%), HS4A (n = 10, 7%), and HS8/17 (n = 10, 7%) covered almost 50% of the strains from enteritis patients and 43% of the isolates from controls. In combination, the CPS genotype and LOS class was not discriminative between cases and controls. Dominant capsular types previously identified in C. jejuni strains isolated from patients with Guillain-Barré syndrome in Bangladesh were rarely detected in strains isolated from the young children. A similar distribution was evident among enteritis- and control-related strains when comparison was done between CPS types and LOS classes. This is the first systematic study presenting the distribution of CPS genotypes of C. jejuni strains isolated in Bangladesh from children with diarrhea and controls, with capsular genotypes HS5/31 complex, HS3, HS4A, and HS8/17 being prevalent in both. In conclusion, systematic studies are required to develop a multivalent capsule-based vaccine for children in low-income countries.

ZikaPLAN: Zika Preparedness Latin American Network

The ongoing Zika virus (ZIKV) outbreak in Latin America, the Caribbean, and the Pacific Islands has underlined the need for a coordinated research network across the whole region that can respond rapidly to address the current knowledge gaps in Zika and enhance research preparedness beyond Zika. The European Union under its Horizon 2020 Research and Innovation Programme awarded three research consortia to respond to this need. Here we present the ZikaPLAN (Zika Preparedness Latin American Network) consortium. ZikaPLAN combines the strengths of 25 partners in Latin America, North America, Africa, Asia, and various centers in Europe. We will conduct clinical studies to estimate the risk and further define the full spectrum and risk factors of congenital Zika virus syndrome (including neurodevelopmental milestones in the first 3 years of life), delineate neurological complications associated with ZIKV due to direct neuroinvasion and immune-mediated responses in older children and adults, and strengthen surveillance for birth defects and Guillain-Barré Syndrome. Laboratory-based research to unravel neurotropism and investigate the role of sexual transmission, determinants of severe disease, and viral fitness will underpin the clinical studies. Social messaging and engagement with affected communities, as well as development of wearable repellent technologies against Aedes mosquitoes will enhance the impact. Burden of disease studies, data-driven vector control, and vaccine modeling as well as risk assessments on geographic spread of ZIKV will form the foundation for evidence-informed policies. While addressing the research gaps around ZIKV, we will engage in capacity building in laboratory and clinical research, collaborate with existing and new networks to share knowledge, and work with international organizations to tackle regulatory and other bottlenecks and refine research priorities. In this way, we can leverage the ZIKV response toward building a long-term emerging infectious diseases response capacity in the region to address future challenges.

Campylobacter jejuni capsular genotypes are related to Guillain-Barré syndrome

In about one in a thousand cases, a Campylobacter jejuni infection results in the severe polyneuropathy Guillain-Barré syndrome (GBS). It is established that sialylated lipo-oligosaccharides (LOS) of C. jejuni are a crucial virulence factor in GBS development. Frequent detection of C. jejuni with sialylated LOS in stools derived from patients with uncomplicated enteritis implies that additional bacterial factors should be involved. To assess whether the polysaccharide capsule is a marker for GBS, the capsular genotypes of two geographically distinct GBS-associated C. jejuni strain collections and an uncomplicated enteritis control collection were determined. Capsular genotyping of C. jejuni strains from the Netherlands revealed that three capsular genotypes, HS1/44c, HS2 and HS4c, were dominant in GBS-associated strains and capsular types HS1/44c and HS4c were significantly associated with GBS (p 0.05 and p 0.01, respectively) when compared with uncomplicated enteritis. In a GBS-associated strain collection from Bangladesh, capsular types HS23/36c, HS19 and HS41 were most prevalent and the capsular types HS19 and HS41 were associated with GBS (p 0.008 and p 0.02, respectively). Next, specific combinations of the LOS class and capsular genotypes were identified that were related to the occurrence of GBS. Multilocus sequence typing revealed restricted genetic diversity for strain populations with the capsular types HS2, HS19 and HS41. We conclude that capsular types HS1/44c, HS2, HS4c, HS19, HS23/36c and HS41 are markers for GBS. Besides a crucial role for sialylated LOS of C. jejuni in GBS pathogenesis, the identified capsules may contribute to GBS susceptibility.

Comparative population structure analysis of Campylobacter jejuni from human and poultry origin in Bangladesh

Campylobacter jejuni is the most important cause of antecedent infections leading to Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS). The objective of the present study was to define the genetic diversity, population structure, and potential role of poultry in the transmission of Campylobacter to humans in Bangladesh. We determined the population structure of C. jejuni isolated from poultry (n = 66) and patients with enteritis (n = 39) or GBS (n = 10). Lipooligosaccharide (LOS) typing showed that 50/66 (76 %) C. jejuni strains isolated from poultry could be assigned to one of five LOS locus classes (A-E). The distribution of neuropathy-associated LOS locus classes A, B, and C were 30/50 (60 %) among the typable strains isolated from poultry. The LOS locus classes A, B, and C were significantly associated with GBS and enteritis-related C. jejuni strains more than for the poultry strains [(31/38 (82 %) vs. 30/50 (60 %), p < 0.05]. Multilocus sequence typing (MLST) defined 15 sequence types (STs) and six clonal complexes (CCs) among poultry isolates, including one ST-3740 not previously documented. The most commonly identified type, ST-5 (13/66), in chicken was seen only once among human isolates (1/49) (p < 0.001). Amplified fragment length polymorphism (AFLP) revealed three major clusters (A, B, and C) among C. jejuni isolated from humans and poultry. There seems to be a lack of overlap between the major human and chicken clones, which suggests that there may be additional sources for campylobacteriosis other than poultry in Bangladesh.

Bacterial proteases: targets for diagnostics and therapy

Proteases are essential for the proliferation and growth of bacteria, and are also known to contribute to bacterial virulence. This makes them interesting candidates as diagnostic and therapeutic targets for infectious diseases. In this review, the authors discuss the most recent developments and potential applications for bacterial proteases in the diagnosis and treatment of bacterial infections. Current and future bacterial protease targets are described and their limitations outlined.

Siglec-7 specifically recognizes Campylobacter jejuni strains associated with oculomotor weakness in Guillain-Barré syndrome and Miller Fisher syndrome

Due to molecular mimicry, Campylobacter jejuni lipo-oligosaccharides can induce a cross-reactive antibody response to nerve gangliosides, which leads to Guillain-Barré syndrome (GBS). Cross-reactive antibodies to ganglioside GQ1b are strongly associated with oculomotor weakness in GBS and its variant, Miller Fisher syndrome (MFS). Antigen recognition is a crucial first step in the induction of a cross-reactive antibody response, and it has been shown that GQ1b-like epitopes expressed on the surface of C. jejuni are recognized by sialic acid-binding immunoglobulin-like lectin-7 (Siglec-7). We aimed to determine the epitope specificity of C. jejuni binding to Siglec-7, and correlate the outcome to disease symptoms in GBS and MFS patients. Using a well-defined GBS/MFS-associated C. jejuni strain collection, which included three sialic acid knockout strains, we found that Siglec-7 exclusively binds to C. jejuni strains that express terminal disialylated ganglioside mimics. When serological and diagnostic patient records were correlated with the Siglec-7-binding properties, we observed an association between Siglec-7 binding and the presence of anti-GQ1b antibodies in patient serum. In addition, Siglec-7 binding was associated with oculomotor weakness in GBS and MFS patients. Lipo-oligosaccharide-specific binding of C. jejuni to Siglec-7 may be an initiating event in immune recognition and presentation, and lead to anti-GQ1b antibody production and the development of ocular weakness in GBS or MFS.

Molecular epidemiology of tuberculosis in rural Matlab, Bangladesh

OBJECTIVE

To characterise and classify clinical isolates collected from tuberculosis (TB) patients in rural Bangladesh and to investigate the mode of transmission.

DESIGN

An epidemiological study using a combination of conventional and molecular methods was performed in a rural population of Bangladesh. A total of 168 clinical isolates were collected from TB patients. Deletion analysis, used for rapid differentiation of members of the Mycobacterium tuberculosis complex, spoligotyping and variable number tandem repeats of mycobacterial interspersed repetitive units (VNTR-MIRU) typing were used.

RESULTS

Deletion analysis identified all isolates as M. tuberculosis and further divided them into 109 strains (65%) carrying the M. tuberculosis deletion region 1 (TbD1-intact or 'ancestral' strains) and 59 strains (35%) lacking this region (TbD1 or 'modern' strains). MIRU analyses showed that 149 strains (89%) had unique patterns, whereas 19 strains (11%) clustered into eight groups. The largest cluster comprised five TbD1 strains of the Beijing type. The rate of recent transmission was estimated to be 6.5%.

CONCLUSIONS

Our results suggest that TB in rural Bangladesh is caused primarily by reactivation of latent infections involving TbD1 intact strains, overlaid with the recent emergence of Beijing strain clusters that include multidrug-resistant isolates.

Emergence of multidrug-resistant NDM-1-producing Gram-negative bacteria in Bangladesh

The main objective of this study was to investigate the prevalence of bla (NDM-1) in Gram-negative bacteria in Bangladesh. In October 2010 at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) laboratories, 1,816 consecutive clinical samples were tested for imipenem-resistant Gram-negative organisms. Imipenem-resistant isolates were tested for the bla (NDM-1) gene. Among 403 isolates, 14 (3.5 %) were positive for bla (NDM-1), and the predominant species were Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli. All bla (NDM-1)-positive isolates were resistant to multiple antibiotics. Among β-lactamase genes, bla (CTX-M-1-group) was detected in ten isolates (eight bla (CTX-M-15)), bla (OXA-1-group) in six, bla (TEM) in nine, bla (SHV) in seven, and bla (VIM) and bla (CMY) in two isolates each. The 16S rRNA methylase gene, armA, was detected in five K. pneumoniae isolates and in one E. coli isolate. rmtB and rmtC were detected in a Citrobacter freundii and two K. pneumoniae isolates, respectively. qnr genes were detected in two K. pneumoniae isolates (one qnrB and one qnrS) and in an E. coli isolate (qnrA). Transferable plasmids (60-100 MDa) carrying bla (NDM-1) were detected in 7 of the 11 plasmid-containing isolates. Pulsed-field gel electrophoresis (PFGE) analysis grouped K. pneumoniae isolates into three clusters, while E. coli isolates differed significantly from each other. This study reports that approximately 3.5 % of Gram-negative clinical isolates in Bangladesh are NDM-1-producing.

Campylobacter bacteremia: a rare and under-reported event?

Bacteria belonging to the species Campylobacter are the most common cause of bacterial diarrhoea in humans. The clinical phenotype associated with Campylobacter infections ranges from asymptomatic conditions to severe colitis and bacteremia. In susceptible patients, Campylobacter infections are associated with significant morbidity and mortality, with both host factors and bacterial factors being involved in the pathogenesis of bacteremia. In the host, age, gender and immune-compromising conditions may predispose for Campylobacter infections, whilst the most important bacterial determinants mentioned in the literature are cytotoxin production and flagellar motility. The role of sialylated lipo-oligosaccharide (LOS) and serum resistance in bacteremia is inconclusive at this time, and the clinical significance of Campylobacter bacteremia is not yet fully understood. More emphasis on the detection of Campylobacter species from blood cultures in susceptible patients at risk for Campylobacter infections will increase our understanding of the pathogenesis and the relevance of Campylobacter bacteremia.

Purification of household water using a novel mixture reduces diarrhoeal disease in Matlab, Bangladesh

In Bangladesh, one of the main causes of waterborne diseases is related to the use of contaminated surface water. This pilot study was conducted to determine the acceptability and effectiveness of a recently developed surface water purifying mixture to prevent diarrhoeal diseases in a rural community in Bangladesh. The mixture, using a combination of alum potash, bleaching powder and lime, is added to 15 l of surface water and mixed; the water becomes suitable for drinking after 30 min. A total of 420 households from 15 villages were provided with the mixture and were taught how to use it. Episodes of diarrhoeal disease from study families were determined from hospital records of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) in Matlab and were compared with diarrhoea episodes among 1613 control families who were not provided with the mixture. A total of 83 diarrhoeal patients were treated at Matlab Hospital from 1613 control families, but only one patient was treated for diarrhoea from among the intervention families. Among the intervention families, 73 families decided to shift from using tube well water to surface water using the mixture. The mixture could be used as a cheaper, easier and simpler point-of-use water treatment strategy in Bangladesh.

Axonal variant of Guillain-Barre syndrome associated with Campylobacter infection in Bangladesh

BACKGROUND

Campylobacter jejuni enteritis is the predominant bacterial infection preceding Guillain-Barré syndrome (GBS), an acute postinfectious immune-mediated polyradiculoneuropathy. The purpose of this study was to define the clinical phenotype of GBS and the relation with preceding C jejuni infections in Bangladesh.

METHODS

We performed a prospective matched case-control hospital surveillance including 100 patients fulfilling the National Institute of Neurological Disorders and Stroke criteria for GBS from 2006 to 2007 in the Dhaka area of Bangladesh. Detailed clinical, electrophysiologic, serologic, and microbiologic data were obtained with a follow-up of 6 months.

RESULTS

GBS affected predominantly young adult males living in rural areas. Sixty-nine percent of the patients had clinical evidence of a preceding infection. The most frequent symptom was diarrhea (36%). The majority of patients had a pure motor variant of GBS (92%) with relatively infrequent cranial nerve involvement (30%). Twenty-five percent of patients required respiratory support. Electrophysiologic studies showed that 67% of patients had an axonal variant of GBS. Eleven patients (14%) died, and 23 (29%) remained severely disabled during the follow-up. Positive C jejuni serology was found in an unprecedented high frequency of 57% as compared with 8% in family controls and 3% in control patients with other neurologic diseases (p < 0.001). C jejuni infection was significantly associated with serum antibodies to the gangliosides GM1 and GD1a, axonal neuropathy, and greater disability.

CONCLUSIONS

We report an unusually high frequency of the axonal variant of Guillain-Barré syndrome in Bangladesh, associated with preceding Campylobacter jejuni infection, severe residual disability, and high mortality.

Effects of local climate variability on transmission dynamics of cholera in Matlab, Bangladesh

Cholera is considered as a model for climate-related infectious diseases. In Bangladesh, cholera epidemics occur during summer and winter seasons, but it is not known how climate variability influences the seasonality of cholera. Therefore, the variability pattern of cholera events was studied in relation to the variation in local climate variables in Matlab, Bangladesh. Classification and regression tree (CART) and principal component analysis (PCA) were used to study the dependency and variability pattern of monthly total cholera cases. An average temperature <23.25 degrees C corresponded to the lowest average cholera occurrence (23 cases/month). At a temperature of >or=23.25 degrees C and sunshine <4.13h/day, the cholera occurrence was 39 cases/month. With increased sunshine (>or=4.13h/day) and temperature (23.25-28.66 degrees C), the second highest cholera occurrence (44 cases/month) was observed. When the sunshine was >or=4.13h/day and the temperature was >28.66 degrees C, the highest cholera occurrence (54 cases/month) was observed. These results demonstrate that in summer and winter seasons in Bangladesh, temperature and sunshine hours compensate each other for higher cholera incidence. The synergistic effect of temperature and sunshine hours provided the highest number of cholera cases.

Evidence of intra-familial transmission of Helicobacter pylori by PCR-based RAPD fingerprinting in Bangladesh

Helicobacter pylori is a genetically diverse bacterial species, which has facilitated adaptation to new hosts and persists worldwide. The main objective of this study was to explore intra-familial transmission of H. pylori in Bangladesh. We characterized H. pylori in 35 families including 138 family members using random amplified polymorphic DNA (RAPD) fingerprinting. Forty-six percent of H. pylori isolated from the mother shared a related genotype with strains isolated from their children. Twenty-nine percent of H. pylori isolates of the mother are related to the youngest children. Only 6% of the parents shared related genotype of H. pylori. These findings suggest that mother-to-child transmission occurs in early childhood and is the most probable route of transmission of H. pylori in Bangladesh.

Molecular typing of a suspected cluster of Nocardia farcinica infections by use of randomly amplified polymorphic DNA, pulsed-field gel electrophoresis, and amplified fragment length polymorphism analyses

Randomly amplified polymorphic DNA (RAPD), pulsed-field gelelectrophoresis (PFGE), and amplified fragment length polymorphism (AFLP) analyses were used to investigate a possible outbreak of Nocardia farcinica. RAPD and PFGE analyses yielded irreproducible and unsatisfactory results, respectively. AFLP analysis seem to be a promising and welcome addition for molecular analysis of Nocardia isolates.

Lack of association between the presence of the pVir plasmid and bloody diarrhea in Campylobacter jejuni enteritis

The main mechanisms by which Campylobacter jejuni causes diarrhea are unknown. In contrast to a recent communication, we report here the absence of an association with the plasmid pVir in patients infected with C. jejuni who developed bloody diarrhea in The Netherlands, and we suggest a role for other virulence determinants.

Comparison of the COBAS AMPLICOR MTB and BDProbeTec ET assays for detection of Mycobacterium tuberculosis in respiratory specimens

The performances of the BDProbeTec ET (Becton Dickinson) and COBAS AMPLICOR MTB (Roche) were retrospectively evaluated for detecting Mycobacterium tuberculosis complex in various respiratory specimens. The BACTEC and MGIT liquid culture system (Becton Dickinson) was used as a reference method. A total of 824 respiratory specimens, comprised of sputa, bronchoalveolar lavage fluid, and bronchial and tracheal aspirates from 580 patients, were evaluated. Out of 824 clinical specimens, 109 specimens from 43 patients were culture positive for M. tuberculosis. Of these 109 specimens, 67 were smear positive, 85 were positive by the COBAS AMPLICOR MTB test, and 94 were positive by the BDProbeTec ET. Of the 715 culture-negative specimens, 17 were positive by the auramine staining, 11 were positive by the COBAS AMPLICOR MTB test, and 12 were positive by the BDProbeTec ET. After discrepancy analysis and review of the patients' clinical data, 130 specimens from 50 patients were considered "true-positive" specimens. This resulted in the following sensitivities: microscopy, 61.5%; COBAS AMPLICOR MTB test, 78.0%; and BDProbeTec ET, 86.2%. The specificities of each system, based on the clinical diagnosis, were 99.7% for microscopy, 99.9% for the COBAS AMPLICOR MTB test, and 99.9% for the BDProbeTec ET. The data presented represent a considerable number of specimens evaluated with a considerable number of culture- and auramine-positive and culture-positive and auramine-negative results and therefore give a realistic view of how the data should be interpreted in a daily routine situation. Specifically, the data with regard to the culture-positive and auramine-negative specimens are useful, because in a routine situation, auramine-negative specimens are sometimes accepted, on clinical indications, to be analyzed by an amplification method.

Effect of Hospitalization on the Antibiotic Resistance of FecalEnterococcus faecalisof Surgical Patients Over Time

The prevalence of antibiotic resistant Enterococcus faecalis was determined in fecal samples of 263 patients admitted to the surgical wards of three university-affiliated hospitals on admission, at discharge, and at 1 and 6 months after discharge. A slight increase in the prevalence of antibiotic resistance of E. faecalis was found at discharge for the antibiotics tested compared to those on admission, vancomycin excepted. At 6 months after discharge, the prevalence of resistance for amoxicillin (0%), ciprofloxacin (3%), erythromycin (47%), and oxytetracycline (60%) decreased to the level on admission (respectively 0%, 8%, 45%, and 64%). Gentamicin resistance was the same at discharge (10%) as 1 month later (12%), but decreased 6 months after discharge (8%) to the level on admission (7%). In conclusion, hospitalization resulted in the study population in a slight increase in the prevalence of resistant fecal E. faecalis isolates at discharge, which decreased again (slowly) to the level on admission 6 months after discharge. Thus, the influence of hospitalization on the prevalence of antibiotic resistance in the extramural situation disappears between 1 and 6 months after discharge in this population.

Comparative evaluation of three chromogenic agars for detection and rapid identification of aerobic Gram-negative bacteria in the normal intestinal microflora

OBJECTIVE

To compare three different chromogenic agars and MacConkey agar for the detection of aerobic Gram-negative bacteria in the normal intestinal microflora and to assess the accuracy of the chromogenic agars for the direct identification of Escherichia coli.

METHODS

A total of 164 Gram-negative clinical isolates (E. coli, Proteus, Klebsiella, Enterobacter, Morganella and Pseudomonas species) and 30 stool specimens were inoculated in parallel on four media: Chromagar E. coli/Coliform, Chromogenic urinary tract infection UTI medium, CHROMagar Orientation and MacConkey agar. All colonies that differed by color and/or morphology were selected for further identification by VITEK 1 and/or API 20E from each medium.

RESULTS

On E. coli/Coliform agar five out of 32 (16%) E. coli strains failed to produce the color as described by the manufacturer. No remarkable discrepancies were found for the other clinical isolates. There was no significant difference in detection rate (DR) of aerobic Gram-negative bacteria in stool specimens between the different chromogenic agars and MacConkey agar. The overall DR was about 84%, and varied from 100% for monomicrobial specimens to 33% for polymicrobial specimens. The positive predictive values (PPV) for the direct identification of E. coli on Chromagar E. coli/Coliform, Chromogenic UTI medium and CHROMagar Orientation were 1.00, 0.93 and 0.93, respectively. The negative predictive values (NPV) were 0.53, 0.68 and 0.69, respectively.

CONCLUSION

Chromogenic UTI medium and CHROMagar Orientation are the preferred media because of the higher NPV. The high PPV of these agars allows accurate and rapid identification of E. coli.

Prospective study of the performance of vibrational spectroscopies for rapid identification of bacterial and fungal pathogens recovered from blood cultures

Rapid identification of microbial pathogens reduces infection-related morbidity and mortality of hospitalized patients. Raman spectra and Fourier transform infrared (IR) spectra constitute highly specific spectroscopic fingerprints of microorganisms by which they can be identified. Little biomass is required, so that spectra of microcolonies can be obtained. A prospective clinical study was carried out in which the causative pathogens of bloodstream infections in hospitalized patients were identified. Reference libraries of Raman and IR spectra of bacterial and yeast pathogens highly prevalent in bloodstream infections were created. They were used to develop identification models based on linear discriminant analysis and artificial neural networks. These models were tested by carrying out vibrational spectroscopic identification in parallel with routine diagnostic phenotypic identification. Whereas routine identification has a typical turnaround time of 1 to 2 days, Raman and IR spectra of microcolonies were collected 6 to 8 h after microbial growth was detected by an automated blood culture system. One hundred fifteen samples were analyzed by Raman spectroscopy, of which 109 contained bacteria and 6 contained yeasts. One hundred twenty-one samples were analyzed by IR spectroscopy. Of these, 114 yielded bacteria and 7 were positive for yeasts. High identification accuracy was achieved in both the Raman (92.2%, 106 of 115) and IR (98.3%, 119 of 121) studies. Vibrational spectroscopic techniques enable simple, rapid, and accurate microbial identification. These advantages can be easily transferred to other applications in diagnostic microbiology, e.g., to accelerate identification of fastidious microorganisms.

Ganglioside mimicry of Campylobacter jejuni lipopolysaccharides determines antiganglioside specificity in rabbits

The core oligosaccharides of Campylobacter jejuni lipopolysaccharides (LPS) display molecular mimicry with gangliosides. Cross-reactive anti-LPS-antiganglioside antibodies have been implicated to show a crucial role in the pathogenesis of the Guillain-Barré and Miller Fisher syndrome. The specificity of the antiganglioside response is thought to depend on the oligosaccharide structure of the ganglioside mimic. To test this hypothesis and to investigate the potential of LPS from Campylobacter strains from enteritis patients to induce an antiganglioside response, we immunized rabbits with purified LPS from eight Campylobacter jejuni reference strains with biochemically well-defined distinct ganglioside mimics and determined the presence of antiganglioside antibodies. All rabbits produced immunoglobulin G (IgM) and IgG anti-LPS antibodies, and the specificity of the cross-reactive antiganglioside response indeed corresponded with the biochemically defined mimic. Most rabbits also had antibody reactivity against additional gangliosides, and there were slight differences in the fine specificity of the antibody response between rabbits that had been immunized with LPS from the same Campylobacter strain. High anti-LPS and antiganglioside titers persisted over a 10-month period. In conclusion, the structure of the LPS only partly determines the antiganglioside specificity. Other strain-specific as well as host-related factors influence the induction and fine-specificity of the cross-reactive anti-LPS-antiganglioside response.

Medical applications of Raman spectroscopy: from proof of principle to clinical implementation

Raman spectroscopy has recently been applied ex vivo and in vivo to address various biomedical issues such as the early detection of cancers, monitoring of the effect of various agents on the skin, determination of atherosclerotic plaque composition, and rapid identification of pathogenic microorganisms. This leap in the number of applications and the number of groups active in this field has been facilitated by several technological advancements in lasers, CCD detectors, and fiber-optic probes. However, most of the studies are still at the proof of concept stage. We present a discussion on the status of the field today, as well as the problems and issues that still need to be resolved to bring this technology to hospital settings (i.e., the medical laboratory, surgical suites, or clinics). Taken from the viewpoint of clinicians and medical analysts, the potential of Raman spectroscopic techniques as new tools for biomedical applications is discussed and a path is proposed for the clinical implementation of these techniques.

Structure of Campylobacter jejuni lipopolysaccharides determines antiganglioside specificity and clinical features of Guillain-Barré and Miller Fisher patients

Ganglioside mimicry in the lipopolysaccharide (LPS) fraction of Campylobacter jejuni isolated from Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) patients was compared with isolates from patients with an uncomplicated enteritis. The antibody response to C. jejuni LPS and gangliosides in neuropathy patients and controls was compared as well. LPS from GBS and MFS-associated isolates more frequently contained ganglioside-like epitopes compared to control isolates. Almost all neuropathy patients showed a strong antibody response against LPS and multiple gangliosides in contrast to enteritis patients. Isolates from GBS patients more frequently had a GM1-like epitope than isolates from MFS patients. GQ1b-like epitopes were present in all MFS-associated isolates and was associated with anti-GQ1b antibody reactivity and the presence of oculomotor symptoms. These results demonstrate that the expression of ganglioside mimics is a risk factor for the development of post-Campylobacter neuropathy. This study provides additional evidence for the hypothesis that the LPS fraction determines the antiganglioside specificity and clinical features in post-Campylobacter neuropathy patients.

Rapid identification of Candida species by confocal Raman microspectroscopy

Candida species are important nosocomial pathogens associated with high mortality rates. Rapid detection and identification of Candida species can guide a clinician at an early stage to prescribe antifungal drugs or to adjust empirical therapy when resistant species are isolated. Confocal Raman microspectroscopy is highly suitable for the rapid identification of Candida species, since Raman spectra can be directly obtained from microcolonies on a solid culture medium after only 6 h of culturing. In this study, we have used a set of 42 Candida strains comprising five species that are frequently encountered in clinical microbiology to test the feasibility of the technique for the rapid identification of Candida species. The procedure was started either from a culture on Sabouraud medium or from a positive vial of an automated blood culture system. Prior to Raman measurements, strains were subcultured on Sabouraud medium for 6 h to form microcolonies. Using multivariate statistical analyses, a high prediction accuracy (97 to 100%) was obtained with the Raman method. Identification with Raman microspectroscopy may therefore be significantly faster than identification with commercial identification systems that allow various species to be identified and that often require 24 to 48 h before a reliable identification is obtained. We conclude that confocal Raman microspectroscopy offers a rapid, accurate, and easy-to-use alternative for the identification of clinically relevant Candida species.

In vitro activities of ertapenem (MK-0826) against recent clinical bacteria collected in Europe and Australia

Ertapenem (MK-0826, L-749,345) is a 1-beta-methyl carbapenem with a long serum half-life. Its in vitro activity was determined by broth microdilution against 3,478 bacteria from 12 centers in Europe and Australia, with imipenem, cefepime, ceftriaxone, and piperacillin-tazobactam used as comparators. Ertapenem was the most active agent tested against members of the family Enterobacteriaceae, with MICs at which 90% of isolates are inhibited (MIC(90)s) of < or =1 microg/ml for all species. Ertapenem also was more active than imipenem against fastidious gram-negative bacteria and Moraxella spp.; on the other hand, ertapenem was slightly less active than imipenem against streptococci, methicillin-susceptible staphylococci, and anaerobes, but its MIC(90)s for these groups remained < or =0.5 microg/ml. Acinetobacter spp. and Pseudomonas aeruginosa were also much less susceptible to ertapenem than imipenem, and most Enterococcus faecalis strains were resistant. Ertapenem resistance, based on a provisional NCCLS MIC breakpoint of > or =16 microg/ml, was seen in only 3 of 1,611 strains of the family Enterobacteriaceae tested, all of them Enterobacter aerogenes. Resistance was also seen in 2 of 135 anaerobes, comprising 1 Bacteroides fragilis strain and 1 Clostridium difficile strain. Ertapenem breakpoints for streptococci have not been established, but an unofficial susceptibility breakpoint of < or =2 microg/ml was adopted for clinical trials to generate corresponding clinical response data for isolates for which MICs were as high as 2 microg/ml. Of 234 Streptococcus pneumoniae strains tested, 2 required ertapenem MICs of 2 microg/ml and one required an MIC of 4 microg/ml, among 67 non-Streptococcus pyogenes, non-Streptococcus pneumoniae streptococci, single isolates required ertapenem MICs of 2 and 16 microg/ml. These streptococci also had diminished susceptibilities to other beta-lactams, including imipenem as well as ertapenem. The Etest and disk diffusion gave susceptibility test results in good agreement with those of the broth microdilution method for ertapenem.

Sequence typing confirms that Campylobacter jejuni strains associated with Guillain-Barré and Miller-Fisher syndromes are of diverse genetic lineage, serotype, and flagella type

Guillain-Barré syndrome (GBS) and Miller-Fisher syndrome (MFS) are correlated with prior infection by Campylobacter jejuni in up to 40% of cases. Nucleotide sequence-based typing of 25 C. jejuni isolates associated with neuropathy permitted robust comparisons with equivalent data from approximately 800 C. jejuni isolates not associated with neuropathy. A total of 13 genetic lineages and 20 flaA short variable region nucleotide sequences were present among the 25 isolates. A minority of isolates (4 of 25) had the flaA short variable region nucleotide sequences that were previously proposed as a marker for GBS-associated isolates. These 4 isolates probably represented the Penner serotype 19 lineage, which has been proposed to have an association with GBS.

Gastroenteritis-associated Guillain-Barré syndrome on the Caribbean island Curaçao

BACKGROUND

The number of patients with Guillain-Barré syndrome (GBS) who have been observed in Curaçao, the Netherlands Antilles, may be increasing.

METHODS

Clinical and serologic data were obtained from records of patients admitted between 1987 and 1999 and fulfilling National Institute of Neurological and Communicative Disorders and Stroke criteria for GBS. When possible, serum and stool samples were collected. The results were compared with a large Dutch epidemiologic study.

RESULTS

The authors identified 49 patients, an overall crude incidence rate (IR) in Curaçao of 2.53/100,000 inhabitants (95% CI 1.87 to 3.35) (Dutch study 1.18, rate ratio (RR) of 2.14, p < 0.001). The IR in Curaçao increased from 1.62 in 1987 to 1991 to 3.10 in 1992 to 1999, RR 5.22 (95% CI 2.48 to 10.2, p = 0.02). The IR showed a curvilinear shape within a year. In comparison with the Dutch group, patients from Curaçao had a more severe course of the disease, with a mortality rate of 23% (3.4% in the Dutch group, p < 0.001), a higher percentage of preceding gastroenteritis (p < 0.001), and less sensory involvement (p < 0.001). In 8 of 10 serum samples, evidence was found for a recent infection with Campylobacter jejuni.

CONCLUSIONS

The authors found a steady increase in incidence of GBS over the years in association with a more pronounced seasonal preponderance and a more severe course. The clinical characteristics suggest a role for C jejuni.

Investigating microbial (micro)colony heterogeneity by vibrational spectroscopy

Fourier transform infrared and Raman microspectroscopy are currently being developed as new methods for the rapid identification of clinically relevant microorganisms. These methods involve measuring spectra from microcolonies which have been cultured for as little as 6 h, followed by the nonsubjective identification of microorganisms through the use of multivariate statistical analyses. To examine the biological heterogeneity of microorganism growth which is reflected in the spectra, measurements were acquired from various positions within (micro)colonies cultured for 6, 12, and 24 h. The studies reveal that there is little spectral variance in 6-h microcolonies. In contrast, the 12- and 24-h cultures exhibited a significant amount of heterogeneity. Hierarchical cluster analysis of the spectra from the various positions and depths reveals the presence of different layers in the colonies. Further analysis indicates that spectra acquired from the surface of the colonies exhibit higher levels of glycogen than do the deeper layers of the colony. Additionally, the spectra from the deeper layers present with higher RNA levels than the surface layers. Therefore, the 6-h colonies with their limited heterogeneity are more suitable for inclusion in a spectral database to be used for classification purposes. These results also demonstrate that vibrational spectroscopic techniques can be useful tools for studying the nature of colony development and biofilm formation.

Guillain-Barré syndrome- and Miller Fisher syndrome-associated Campylobacter jejuni lipopolysaccharides induce anti-GM1 and anti-GQ1b Antibodies in rabbits

Campylobacter jejuni infections are thought to induce antiganglioside antibodies in patients with Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) by molecular mimicry between C. jejuni lipopolysaccharides (LPS) and gangliosides. We used purified LPS fractions from five Campylobacter strains to induce antiganglioside responses in rabbits. The animals that received injections with LPS from GBS-associated strains developed anti-GM1 and anti-GA1 antibodies. Animals injected with LPS from one MFS-related C. jejuni strain produced anti-GQ1b antibodies. Rabbits that were injected with Penner O:3 LPS had a strong anti-LPS response, but no antiganglioside reactivity was observed. The antiganglioside specificity in the rabbits reflected the specificity in the patients from whom the strains were isolated. In conclusion, our results indicate that an immune response against GBS- and MFS-associated C. jejuni LPS results in antiganglioside antibodies. These results provide strong support for molecular mimicry as a mechanism in the induction of antiganglioside antibodies following infections.

Accuracy of the VITEK 2 system to detect glycopeptide resistance in enterococci

We evaluated the accuracy of the VITEK 2 fully automated system to detect and identify glycopeptide-resistant enterococci (GRE) compared to a reference agar dilution method. The sensitivity of vancomycin susceptibility testing with VITEK 2 for the detection of vanA, vanB, and vanC1 strains was 100%. The sensitivity of vancomycin susceptibility testing of vanC2 strains was 77%. The sensitivity of teicoplanin susceptibility testing of vanA strains was 90%. Of 80 vanC enterococci, 78 (98%) were correctly identified by VITEK 2 as Enterococcus gallinarum/Enterococcus casseliflavus. Since the identification and susceptibility data are produced within 3 and 8 h, respectively, VITEK 2 appears a fast and reliable method for detection of GRE in microbiology laboratories.

Random amplification of polymorphic DNA versus pulsed field gel electrophoresis of SmaI DNA macrorestriction fragments for typing strains of vancomycin-resistant enterococci

Genetic typing of vancomycin-resistant enterococci (VRE) can be performed using a variety of methods, but comparative analyses of the quality of these methods are still relatively scarce. We here compare random amplification of polymorphic DNA (RAPD) analysis with pulsed field gel electrophoresis (PFGE) of DNA macrorestriction fragments as examples of two of the recent and well-accepted molecular typing methods. For the latter method, empirical guidelines for the interpretation of the DNA fingerprints have been proposed in the international literature. Based on our experimental analyses, we define similar criteria for RAPD fingerprinting. A collection of 100 strains of VRE, comprising Enterococcus faecium, Enterococcus faecalis, Enterococcus avium, Enterococcus gallinarum and Enterococcus casseliflavus, was assembled. Fifty isolates were Dutch, another 50 were isolated in the UK. Strains were selected on the basis of previously determined putative identity, close relatedness or uniqueness. The strains were analysed using well-standardised RAPD and PFGE protocols. Resulting fingerprints were interpreted with computerised methods involving band positioning and we show that typing of VRE by PFGE and RAPD generates highly congruent DNA fingerprint clustering. When the proposed international criteria for interpretation of PFGE fingerprints were applied in our case, 86% PFGE homology as discriminating value between close relatedness and uniqueness, a 75% homology cut-off for the comparison of the RAPD-generated DNA fingerprints revealed essentially identical strain clusters. As a spin-off it is revealed that strains from the different species can be efficiently discriminated, that strains from the UK and The Netherlands form separate clusters and that strains from veterinary origin can be identified separately as well.

A case of Guillain-Barré syndrome following a family outbreak of Campylobacter jejuni enteritis

We describe an outbreak of Campylobacter jejuni enteritis involving three family members of whom one developed Guillain-Barré syndrome (GBS). The patients' serum reacted strongly with several gangliosides and with the lipopolysaccharide (LPS) fractions from the C. jejuni strains isolated from his family members. Only low titer anti-ganglioside antibodies were found in his siblings. HLA-typing did not indicate a locus associated with auto-antibody production. Comparing the immune response in GBS patients and C. jejuni enteritis patients can be of great value in determining the additional factors that lead to post-Campylobacter GBS. Ganglioside mimicry alone is necessary but not sufficient for the induction of anti-ganglioside antibodies. Other susceptibility factors are required to induce an anti-neural immune response.

Evaluation of a new commercial immunoassay for rapid detection of Campylobacter jejuni in stool samples

In order to evaluate a new commercial enzyme immunoassay (ProspecT Campylobacter Microplate Assay; Alexon-Trend, USA) for the detection of Campylobacter jejuni and Campylobacter coli in stool samples, 30 faecal specimens known to be culture-positive for Campylobacter jejuni were tested with the new assay. The detection limit was approximately 3 x 10(6)/ml in faecal suspensions. The sensitivity relative to culture was 80% (24/30). All of the 24 positive samples, except for one, remained positive after being stored at -20 degrees C for 60 days. The specificity of the test was 100%. Interestingly, 6 of 11 additional Campylobacter jejuni culture-positive samples that had been obtained from patients with Guillain-Barré syndrome and stored at -20 degrees C for periods of up to 5 years tested positive in the assay. The performance of the assay indicates that it has potential value for use in future early intervention studies.

Amplified fragment length polymorphism analysis of Campylobacter jejuni strains isolated from chickens and from patients with gastroenteritis or Guillain-Barré or Miller Fisher syndrome

The high-resolution genotyping method of amplified fragment length polymorphism (AFLP) analysis was used to study the genetic relationships between Campylobacter jejuni strains infecting chickens (n = 54) and those causing gastroenteritis in humans (n = 53). In addition, C. jejuni strains associated with the development of Guillain-Barré syndrome (GBS) (n = 14) and Miller Fisher syndrome (MFS) (n = 4), two related acute paralytic syndromes in human, were included. Strains were isolated between 1989 and 1998 in The Netherlands. The AFLP banding patterns were analyzed with correlation-based and band-based similarity coefficients and UPGMA (unweighted pair group method using average linkages) cluster analysis. All C. jejuni strains showed highly heterogeneous fingerprints, and no fingerprints exclusive for chicken strains or for human strains were obtained. All strains were separated in two distinct genetic groups. In group A the percentage of human strains was significantly higher and may be an indication that genotypes of this group are more frequently associated with human diseases. We conclude that C. jejuni from chickens cannot be distinguished from human strains and that GBS or MFS related strains do not belong to a distinct genetic group.

Prevalence and determinants of fecal colonization with vancomycin-resistant Enterococcus in hospitalized patients in The Netherlands

OBJECTIVE

To determine the prevalence and determinants of fecal carriage of vancomycin-resistant enterococci (VRE) in intensive care unit (ICU), hematology-oncology, and hemodialysis patients in The Netherlands.

DESIGN

Descriptive, multicenter study, with yearly 1-week point-prevalence assessments between 1995 and 1998.

POPULATION

All patients hospitalized on the testing days in ICUs and hematology-oncology wards in nine hospitals in The Netherlands were included.

METHODS

Rectal swabs obtained from 1,112 patients were screened for enterococci in a selective broth and subcultured on selective media with and without 6 mg/L vancomycin. Resistance genotypes were determined by polymerase chain reaction. Further characterization of VRE strains was done by pulsed-field gel electrophoresis (PFGE). We studied possible determinants of VRE colonization with a logistic regression analysis model. Determinants analyzed included gender, age, and log-transformed length of prior hospital stay.

RESULTS

The results showed that 614 (55%) of 1,112 patients were colonized with vancomycin-sensitive enterococci, and 15 (1.4%) of 1,112 carried VRE. No increase in VRE colonization was observed from 1995 to 1998. Eleven strains were identified as Enterococcus faecium and four as Enterococcus faecalis. All E faecium and one E faecalis carried the vanA gene; the other E faecalis strains harbored the vanB gene. PFGE revealed that three vanB VRE isolated from patients hospitalized in one single ICU were related, suggesting nosocomial transmission. Though higher age seemed associated with VRE colonization, exclusion of patients with the nosocomial strain from the regression analysis decreased this relation to nonsignificant. Duration of hospital stay was not associated with VRE colonization.

CONCLUSION

VRE colonization in Dutch hospitals is an infrequent phenomenon. Although nosocomial spread occurs, most observed cases were unrelated, which suggests the possibility of VRE acquisition from outside the hospital. Prolonged hospital stay, age, and gender proved unrelated to VRE colonization.

Molecular characterization of Campylobacter jejuni from patients with Guillain-Barré and Miller Fisher syndromes

Campylobacter jejuni has been identified as the predominant cause of antecedent infection in Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS). The risk of developing GBS or MFS may be higher after infection with specific C. jejuni types. To investigate the putative clonality, 18 GBS- or MFS-related C. jejuni strains from The Netherlands and Belgium and 17 control strains were analyzed by serotyping (Penner and Lior), restriction fragment length polymorphism analysis of PCR products of the flaA gene, amplified fragment length polymorphism analysis, pulsed-field gel electrophoresis, and randomly amplified polymorphic DNA analysis. Serotyping revealed 10 different O serotypes and 7 different Lior serotypes, thereby indicating a lack of serotype clustering. Two new O serotypes, O:35 and O:13/65, not previously associated with GBS or MFS were found. Serotype O:19 was encountered in 2 of 18 strains, and none was of serotype O:41. The results of all genotypic methods also demonstrated substantial heterogeneity. No clustering of GBS- or MFS-related strains occurred and no molecular marker capable of separating pathogenic GBS or MFS from non-GBS- or non-MFS-related enteritis strains could be identified in this study. Sialic-acid-containing lipopolysaccharides (LPS) are thought to be involved in the triggering of GBS or MFS through molecular mimicry with gangliosides in human peripheral nerves. Therefore, further characterization of GBS- or MFS-related C. jejuni should target the genes involved in the synthesis of LPS and the incorporation of sialic acid.

Campylobacter jejuni lipopolysaccharides from Guillain-Barré syndrome patients induce IgG anti-GM1 antibodies in rabbits

Lipopolysaccharides (LPS) from Campylobacter jejuni strains isolated from patients with Guillain-Barré syndrome (GBS) display molecular mimicry with GM1. We immunized rabbits with C. jejuni LPS from GBS-associated strains containing a GM1-like epitope. All animals produced high titre anti-LPS antibodies that were cross-reactive with GM1. We conclude that C. jejuni strains from GBS patients are able to induce antibodies that cross-react with gangliosides and LPS. This study further confirms the role of molecular mimicry in the induction of anti-ganglioside antibodies in GBS patients.

Raman spectroscopic method for identification of clinically relevant microorganisms growing on solid culture medium

Routine clinical microbiological identification of pathogenic microorganisms is largely based on nutritional and biochemical tests. In the case of severely ill patients, the unavoidable time delay associated with such identification procedures can be fatal. We present a novel identification method based on confocal Raman microspectroscopy. With this approach it is possible to obtain Raman spectra directly from microbial microcolonies on the solid culture medium, which have developed after only 6 h of culturing for the most commonly encountered organisms. Due to the limited thickness of microcolonies, some of the underlying culture medium is sampled together with the bacteria. Spectra measured at different depths in a microcolony contain different amounts of the medium signal. A mathematical routine, involving vector algebra, is described for the nonsubjective correction of spectra for variable signal contributions of the medium. To illustrate the possibilities of our approach for the identification of microorganisms, Raman spectra were collected from 6-h microcolonies of five bacterial strains on solid culture medium. The classification results show that confocal Raman microspectroscopy has great potential as a powerful new tool in clinical diagnostic microbiology.

The prevalence and clonal expansion of high-level gentamicin-resistant enterococci isolated from blood cultures in a Dutch university hospital

We studied the prevalence and clonality of high-level gentamicin-resistant enterococci (HLGRE) in a Dutch university hospital. Of 238 enterococcal strains isolated from blood cultures between 1991 and 1997, 57 were HLGRE. Genomic analysis of these strains revealed 19 different genotypes, two of which were encountered more frequently [type A (12/57), type B (23/57)]. The spread of these types largely explained the rise in HLGRE incidence from 14% in 1991 to 31% in 1997. However, the contribution of unique strains to the total HLGRE burden also increased from 4% to 16%. We conclude that both clonal expansion and the emergence of unique HLGRE have contributed significantly to the increasing incidence of HLGRE.

Vancomycin resistance: status quo and quo vadis

The prevalence of vancomycin resistance is steadily rising among clinical isolates of Enterococcus spp., thereby limiting the treatment options for infections caused by vancomycin-resistant enterococci. The precise nature of the glycopeptide resistance genes has been elucidated, and many studies on gene reservoirs and strain-versus-resistance-gene epidemiology have been performed. The prevalence of vancomycin-resistant enterococci in various clinical and environmental settings in relation to nosocomial and veterinary applications of antimicrobial glycopeptides is discussed in detail in this review. Novel molecular tools for the identification of vancomycin-resistant enterococci genomes or the various resistance genes have been applied in order to expand current insight into the overall epidemiology of the resistance trait itself. The risk of the spread of vancomycin resistance to other bacterial species was recently underscored by the emergence of staphylococci showing clinical resistance to vancomycin. The topics mentioned above are elaborated on and discussed in light of the increasing medical concern on the future detection of microbial infections beyond chemotherapeutic cure.

Atypical mycobacterium infection with dermatological manifestation in a renal transplant recipient

In April 1997, a 58-year-old renal transplant recipient presented with abscess-like nodules in his left calf and on his right foot. Furuncular disease was suspected and the patient was treated with flucloxacillin. However, the lesions increased in size and became ulcerative. In the following 3 months, cultures of punctuated material, blood, and urine remained negative and gram stains did not reveal micro-organisms. In June 1997, acid-fast stains were positive. A diagnosis of a nontuberculous mycobacterium (NTM) infection was made and empirical antimycobacterial therapy was started. The combination of relatively minor symptoms with enlarged purulent lesions, causing severe morbidity, raises the possibility of NTM infection in the immunocompromised patient.

Molecular characterization of vancomycin-resistant enterococci from hospitalized patients and poultry products in The Netherlands

Vancomycin-resistant enterococci (VRE) pose an emerging health risk, but little is known about the precise epidemiology of the genes coding for vancomycin resistance. To determine whether the bacterial flora of consumer poultry serves as a gene reservoir, the level of contamination of poultry products with VRE was determined. VRE were genotyped by pulsed-field gel electrophoresis (PFGE), and transposon structure mapping was done by PCR. The vanX-vanY intergenic regions of several strains were further analyzed by sequencing. A total of 242 of 305 (79%) poultry products were found to be contaminated with VRE. Of these VRE, 142 (59%) were high-level-vancomycin-resistant Enterococcus faecium strains (VREF). PFGE revealed extensive VREF heterogeneity. Two genotypes were found nationwide on multiple occasions: type A (22 of 142 VREF [15%]) and type B (14 of 142 VREF [10%]). No PFGE-deduced genetic overlap was found when VREF from humans were compared with VREF from poultry. Two vanA transposon types were identified among poultry strains. In 59 of 142 (42%) of the poultry VREF, the size of the intergenic region between vanX and vanY was approximately 1,300 bp. This transposon type was not found in human VREF. In contrast, all human strains and 83 of 142 (58%) of the poultry VREF contained an intergenic region 543 bp in size. Sequencing of this 543-bp intergenic vanX-vanY region demonstrated full sequence conservation. Though preliminary, these data suggest that dissemination of the resistance genes carried on transposable elements may be of greater importance than clonal dissemination of resistant strains. This observation is important for developing strategies to control the spread of glycopeptide resistance.

Prognostic importance of gram-negative intestinal colonization preceding pancreatic infection in severe acute pancreatitis. Results of a controlled clinical trial of selective decontamination

OBJECTIVES

To establish, firstly, whether gram-negative (re)-colonization of the gut leads to an increased risk of gram-negative pancreatic infections and whether this event is time-related and, secondly, whether the difference in the quantity and quality of micro-organisms colonizing the digestive tract influences morbidity and mortality.

DESIGN

Prospective analysis of the results of systematic semi-quantitative cultures of several body areas taken from patients with severe acute pancreatitis, during a controlled multicenter trial of adjuvant selective decontamination.

SETTING

Surgical intensive care units of 16 hospitals.

PATIENTS

A total of 2,159 semi-quantitative cultures from the oropharynx, rectum and pancreatic tissues taken from 90 patients were analyzed.

INTERVENTIONS

Surveillance cultures from the oropharynx and rectum were taken on admission and repeated twice weekly and from the (peri)-pancreatic devitalized tissues (i. e. necrosis) at every relaparotomy and from drainage.

MEASUREMENTS AND RESULTS

All gram-negative pancreatic infections were preceded by intestinal colonization with the same micro-organisms. The risk of developing a pancreatic infection following gram-negative intestinal colonization (15/42 patients) was significantly higher as compared to patients without gram-negative colonization (0/10 patients) (p < 0.001) or to patients in whom E. coli was the only intestinal micro-organism cultured (0/30 patients) (p < 0.001). The occurrence of intestinal E. coli did not increase the risk of pancreatic infection. Gram-negative colonization of the rectum and oropharynx significantly correlated with the later development of pancreatic infection: relative risks 73.7 (p < 0.001) and 13.6 (p < 0.001), respectively. However, when both areas were evaluated simultaneously, the rectum was more significant (p < 0.001). The severity of intestinal intestinal colonization until the moment of pancreatic infection showed an increase in time in all 15 patients. In 11 of 15 patients (73%) these infections occurred within 1 week following the first isolation from the digestive tract. Gram-negative intestinal colonization was associated with a 3.7 fold increased mortality risk (p = 0.004).

CONCLUSIONS

Gram-negative intestinal colonization, E. coli excepted, is an early prognostic parameter in patients in whom pancreatic infection has not yet occurred and represents a significantly increased risk of pancreatic infections and mortality.

Rapid identification of diverse Campylobacter lari strains isolated from mussels and oysters using a reverse hybridization line probe assay

Campylobacters isolated from mussels and oysters in The Netherlands were analysed by a novel assay, based on DNA amplification with primers, based on semiconserved GTP-binding sites of a putative GTPase gene. Polymerase chain reaction (PCR) was followed by a single step reverse hybridization line probe assay (PCR-LiPA). This permits identification of Campylobacter jejuni, C. coli, C. lari and C. upsaliensis. Among a group of 44 isolates, three C. jejuni, one C. upsaliensis, one double infection with C. jejuni and C. coli, and 38 C. lari strains were identified. These results were in complete agreement with conventional identification methods and whole cell protein analysis. One C. hyointestinalis isolate was not identified by the PCR-LiPA, since the reverse hybridization assay does not comprise specific probes for this particular species. PCR products from 36 C. lari isolates were sequenced and phylogenetic analysis revealed the presence of two major C. lari subgroups: one comprised 11 highly homologous sequences, whereas the 25 sequences in the other subgroup were more heterogeneous. This confirmed earlier findings that C. lari isolates comprise a more heterogeneous group of isolates as compared with C. jejuni, C. coli and C. upsaliensis. Based on the sequence information, a novel PCR-LiPA was developed that permits specific and rapid detection of the different C. lari variants.

Comparison of eight methods to detect vancomycin resistance in enterococci

A collection of genetically unrelated vancomycin-resistant enterococci (VRE) including 50 vanA, 15 vanB, 50 vanC1, and 30 vanC2 VRE were used to evaluate the accuracy of eight currently available susceptibility test methods (agar dilution, disk diffusion, E-test, agar screen plate, Vitek GPS-TA and GPS-101, and MicroScan overnight and rapid panels). vanA VRE were detected by all methods. vanB VRE were often not detected by Vitek GPS-TA and MicroScan rapid (sensitivities, 47 and 53%, respectively), though the new Vitek GPS-101 was found to be a significant improvement. E-test and the agar screen were the only two methods detecting all VRE, including the vanC1/C2 VRE.

Guillain-Barré syndrome: multifactorial mechanisms versus defined subgroups

The clinical spectrum of Guillain-Barré syndrome (GBS) is summarized in relation to antecedent infections and anti-ganglioside antibodies. Associations exist between a pure motor form of GBS, diarrhea, Campylobacter jejuni infection, and anti-GM1 antibodies; between cranial nerve involvement and Miller Fisher syndrome, C. jejuni infection, and anti-GQ1b antibodies; and between variants, such as severe sensory involvement and cytomegalovirus infection. These three clinical variants are suggested to form the extremes of a continuous spectrum; they are discussed in relation to the more pathologically defined patterns of acute motor axonal neuropathy and acute motor-sensory axonal neuropathy. In particular, patients with a clinically pure motor variant of GBS, diarrhea, anti-GM1 antibodies, or C. jejuni infection seem to respond better to early treatment with high-dose immunoglobulins than to plasma exchange.