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PubMed2026

Assessing the threat of Bacillus cereus: From toxin characterization to modern detection strategies.

Bacillus cereus is a spore-forming pathogen responsible for both diarrheal and emetic foodborne illnesses worldwide. Its significance in food safety has received growing attention. Recent advances, including the discovery of novel virulence factors and the development of emerging detection technologies, have provided new insights into its pathogenic mechanisms and surveillance strategies. This review critically examines the global burden of B. cereus infections, and molecular mechanisms of its major virulence factors, and the performance characteristics of current detection knowledge gaps such as the viable-but-non-culturable state and regulatory blind spots for emetic toxins, and discuss unresolved challenges in clinical management. By integrating epidemiological, microbiological, and technological perspectives with critical lens, this review aims to provide a valuable reference for future research and food safety practices.

Bacillus cereus↗
PubMed2005

Thinking the unthinkable: Alzheimer's, Creutzfeldt-Jakob and Mad Cow disease: the age-related reemergence of virulent, foodborne, bovine tuberculosis or losing your mind for the sake of a shake or burger.

The possibility of the age-related reemergence of foodborne Mycobacterium bovis (bovine tuberculosis) as a vector for Creutzfeldt-Jakob Disease (CJD or human Mad Cow Disease) and Mad Cow disease itself is real. The CDC reported last May of an outbreak of CJD linked to the consumption of meat contaminated "with the agent causing" bovine spongiform encephalopathy (BSE) in a New Jersey racetrack between the time frame 1995-2004. In the opinion of experts, ample justification exists for considering a similar pathogenesis for Alzheimer's, Creutzfeldt-Jakob and the other spongiform encephalopathies such as Mad Cow disease. In fact, Creutzfeldt-Jakob and Alzheimer's often coexist and at this point are thought to differ merely by time-dependent physical changes. A recent study links up to 13% of all "Alzheimer's" victims as really having Creutzfeldt-Jakob disease. Bovine tuberculosis, which includes Mycobacterium bovis and M. avium-intracellulare or paratuberculosis, is and has always been the most prevalent threat to the cattle industry, and the USDA reports that between 20% and 40% of US dairy herds are infected with paratuberculosis alone. The health risk for milk tainted with M. bovis has been known for decades and there was a time not so long ago when "tuberculin-tested" was printed on every milk container. Schliesser stated that meat from tuberculous animals may also constitute a significant risk of infection. At the turn of the 20th century 25% of the many US deaths from TB in adults were caused by M. bovis. Dairy products aside, when past and present meat consumption are factored in, there is three times the risk of developing Alzheimer's in meat eaters as opposed to vegetarians. The investigation into the causal trail for Creutzfeldt-Jakob, indistinguishable from Alzheimer's except for its shorter, lethal course might have grown cold where it not for Roel's and others who linked mad cow in cattle with M. bovis and related paratuberculosis on clinical, pathologic and epidemiological grounds. The southwest of the UK, the very cradle of British BSE and CJD outbreaks, saw an exponential increase in bovine tuberculosis just prior to it's spongiform outbreaks. All of this brings up the unthinkable: that Alzheimer's, Cruetzfeldt-Jackob, and Mad Cow Disease might just be caused by eating the meat or dairy in consumer products or feed. It is only appropriate therefore to explore the role of bovine TB and the atypical mycobacteria in Alzheimer's, JCD and Mad Cow disease and develop better serological surveillance for these pathogens.

Alzheimer Disease↗
PubMedDate not supplied

Behavioural characteristics, prevalence of Chlamydia trachomatis and antibiotic susceptibility of Neisseria gonorrhoeae in men with urethral discharge in Thyolo, Malawi.

A study was carried out in 2000/2001 in a rural district of Malawi among men presenting with urethral discharge, in order to (a) describe their health-seeking and sexual behaviour, (b) determine the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis, and (c) verify the antibiotic susceptibility of N. gonorrhoeae. A total of 114 patients were entered into the study; 61% reported having taken some form of medication before coming to the sexually transmitted infections clinic. The most frequent alternative source of care was traditional healers. Sixty-eight (60%) patients reported sexual encounters during the symptomatic period, the majority (84%) not using condoms. Using ligase chain reaction on urine, N. gonorrhoeae was detected in 91 (80%) and C. trachomatis in 2 (2%) urine specimens. Forty five of 47 N. gonorrhoeae isolates produced penicillinase, 89% showing multi-antimicrobial resistance. This study emphasizes the need to integrate alternative care providers and particularly traditional healers in control activities, and to encourage their role in promoting safer sexual behaviour. In patients presenting with urethral discharge in our rural setting, C. trachomatis was not found to be a major pathogen. Antimicrobial susceptibility surveillance of N. gonorrhoeae is essential in order to prevent treatment failures and control the spread of resistant strains.

Adolescent↗
PubMed2001

Infections after stem cell transplantation in children: state of the art and recommendations.

At the workshop on infections after stem cell transplantation (SCT) in children, the following topics were introduced by invited speakers and discussed with the audience: empirical antimicrobial therapy in the pre-engraftment period, early diagnosis of fungal and viral infections and possibilities to treat them and the possible role of G-CSF early post-SCT. Episodes of fever in the pre-engraftment period mostly are unexplained, and in about one quarter due to bacteremia, mostly by Gram-positive cocci. No single drug or combination of drugs used for antimicrobial therapy is superior, neither does it cover 100% of the pathogens. Close microbiological surveillance of the patients and knowledge of the local microbial epidemiology are requested for optimal therapy. Early fungal infections are reactivations of pre-SCT infections, late fungal infections mostly are associated with failure of engraftment or GvHD and its treatment. Except for suggestive ultrasound or CT-scan abnormalities, the possibilities for early diagnosis are limited c.q. not reliable. Fluconazol prophylaxis is recommended to prevent Candida albicans invasion. A number of new antifungal drugs are being tested in phase I and II studies. CMV, EBV and adenoviruses may reactivate after SCT, causing severe disease with a high mortality, especially in non-HLA-identical donor-recipient combinations. Frequent surveillance cultures for CMV and adenoviruses, pp65-CMV antigen detection in WBC and PCR techniques for CMV, EBV and adenoviruses all have their own contribution to the early diagnosis of dissemination of the viral infection. Therapeutical possibilities, except with respect to ganciclovir and foscarnet for CMV infection, are still limited. The effectiveness of cidofovir is under study. Adoptive therapy with virus-specific CTL's probably represents the new frontier. G-CSF administration early after SCT has a beneficial effect on PMN recovery, hospitalization time, use of antibiotics and total parenteral nutrition requirement in children undergoing allogeneic and autologous BMT. No benefit is observed in children undergoing peripheral blood SCT. The routine use of G-CSF in the latter group of patients is not justified.

Anti-Bacterial Agents↗
PubMed2005

Selective accumulation of differentiated CD8+ T cells specific for respiratory viruses in the human lung.

The lungs are frequently challenged by viruses, and resident CD8(+) T cells likely contribute to the surveillance of these pathogens. To obtain insight into local T cell immunity to respiratory viruses in humans, we determined the specificity, phenotype, and function of lung-residing CD8(+) T cells and peripheral blood CD8(+) T cells in a paired analysis. The lung contained markedly higher frequencies of influenza (FLU)-specific and respiratory syncytial virus (RSV)-specific CD8(+) T cells when compared with the circulation. This contrasted with an equal distribution of cytomegalovirus- and Epstein-Bar virus-specific CD8(+) T cells. Noticeably, a substantial fraction of the lung-residing FLU- and RSV-specific CD8(+) T cells had progressed to a relatively late differentiation phenotype, reflected by low expression of CD28 and CD27. Lung-derived FLU-specific CD8(+) T cells had low activation requirements, as expansion of these cells could be initiated by cognate peptide in the absence of helper cell-derived signals. Thus, the human lung contains high numbers of differentiated FLU- and RSV-specific memory CD8(+) T cells that can readily expand upon reexposure to virus. Resident lung T cells may provide immediate immunological protection against pulmonary virus infections.

Aged↗
PubMed2001

Worldwide prevalence of antimicrobial resistance in Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in the SENTRY Antimicrobial Surveillance Program, 1997-1999.

The in vitro activities of numerous antimicrobials against clinical isolates of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis from patients with bloodstream and respiratory tract infections in the United States, Canada, Europe, Latin America, and the Asia-Pacific region were studied in the SENTRY Antimicrobial Surveillance Program. Penicillin resistance (minimum inhibitory concentration, > or =2 microg/mL) was noted in all 5 geographic regions, and a high and increasing rate of macrolide resistance among S. pneumoniae isolates was observed. Elevated rates of resistance to clindamycin, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline were seen. beta-Lactamase-mediated resistance in H. influenzae to amoxicillin and variable trimethoprim-sulfamethoxazole resistance by region were documented. Resistance to several drugs continues to emerge among pneumococci worldwide, but more stable resistance patterns have been noted for H. influenzae and M. catarrhalis. Continued surveillance of this pathogen group appears to be prudent.

Anti-Bacterial Agents↗
PubMed2006

Antimicrobial resistance and genetic relatedness among Salmonella from retail foods of animal origin: NARMS retail meat surveillance.

Salmonella isolates were recovered from a monthly sampling of chicken breasts, ground turkey, ground beef, and pork chops purchased from selected grocery stores in six participating FoodNet sites (Connecticut, Georgia, Maryland, Minnesota, Oregon, and Tennessee) in 2002 and an additional two sites in 2003 (California and New York). In 2002 and 2003, a total of 6,046 retail meats were examined, including 1,513 chicken breasts, 1,499 ground turkey samples, 1,522 ground beef samples, and 1,502 pork chops. Retail meat samples tested increased to 3,533 in 2003 as compared to 2,513 in 2002. Overall, six percent of 6,046 retail meat samples (n = 365) were contaminated with Salmonella, the bulk recovered from either ground turkey (52%) or chicken breast (39%). Salmonella isolates were serotyped and susceptibility tested using a panel of 16 antimicrobial agents. S. Heidelberg was the predominant serotype identified (23%), followed by S. Saintpaul (12%), S. Typhimurium (11%), and S. Kentucky (10%). Overall, resistance was most often observed to tetracycline (40%), streptomycin (37%), ampicillin (26%), and sulfamethoxazole (25%). Twelve percent of isolates were resistant to cefoxitin and ceftiofur, though only one isolate was resistant to ceftriaxone. All isolates were susceptible to amikacin and ciprofloxacin; however, 3% of isolates were resistant to nalidixic acid and were almost exclusive to ground turkey samples (n = 11/12). All Salmonella isolates were analyzed for genetic relatedness using pulsed-field gel electrophoresis (PFGE) patterns generated by digestion with Xba1 or Xba1 plus Bln1. PFGE fingerprinting profiles showed that Salmonella, in general, were genetically diverse with a total of 175 Xba1 PFGE profiles generated from the 365 isolates. PFGE profiles showed good correlation with serotypes and in some instances, antimicrobial resistance profiles. Results demonstrated a varied spectrum of antimicrobial resistance and PFGE patterns, including several multidrug resistant clonal groups among Salmonella isolates, and signify the importance of sustained surveillance of foodborne pathogens in retail meats.

Animals↗
PubMed1989

Toxin genotypes and plasmid profiles as determinants of systemic sequelae in Escherichia coli O157:H7 infections.

In 1987, 93 Escherichia coli O157:H7 isolates were collected during routine surveillance for this pathogen in the state of Washington. Toxin genotypes and plasmid profiles were correlated with the clinical sequelae of illness in 88 of the 93 patients from whom these strains were isolated. Thirteen plasmid patterns were observed among the 88 tested isolates; four patterns accounted for 82% of the isolates. Genetic probing for Shiga-like toxins (SLT) I and II demonstrated the presence of both genes in 67 (76%), SLT I alone in three (3%), and SLT II alone in 18 (20%). The hemolytic uremic syndrome or thrombotic thrombocytopenic purpura developed in seven (39%) of 18 patients infected with isolates having only the SLT II gene, while these complications occurred in only four (6%) of 70 patients infected with isolates having the other two genotypes (relative risk, 6.8; 95% confidence interval, 1.9, 26.4). This study shows that E. coli O157:H7 isolates systematically collected from a single geographic region over a defined time period exhibit considerable diversity in plasmid content and toxin genotype and that the toxin genotype of the infecting strain may influence the risk of developing microangiopathic sequelae.

Age Factors↗
PubMed1996

Biology and therapeutic uses of myeloid hematopoietic growth factors and interferons.

Recent advances in basic science and clinical trials have demonstrated that IFNs and myeloid hematopoietins play crucial roles in host defense against pathogens and immune surveillance. Here we have reviewed the biologic functions of GM-CSF, G-CSF, IFN-alpha and IFN-gamma. For patients with neutropenia resulting from cytotoxic chemotherapy, bone marrow transplantation, congenital agranulocytosis and cyclic neutropenia, therapeutic uses of GM-CSF and G-CSF were reviewed. Application of these growth factors to patient management represents a major contribution of biotechnology to a difficult area of therapeutics in febrile, neutropenic patients. Because IFN-alpha plays crucial roles in antiviral responses, its clinical applications in hepatitis B and C, human papilloma virus, HIV infection and malignancy were discussed. The use of IFN-gamma in bacterial prophylaxis in patients with chronic granulomatous disease was also presented. Advances in clinical applications of IFNs and hematopoietic growth factors serve as a paradigm for further development to investigate the use of other important cytokines in modern therapeutics.

Granulocyte Colony-Stimulating Factor↗
PubMed2005

Basic science for the clinician 35: CD1, invariant NKT (iNKT) Cells, and gammadelta T-cells.

As noted in previous articles in this series, the very heterogeneous MHC class I and II molecules present peptide antigens to T-cells. However, there is another family of less heterogeneous MHC-related molecules. CD1 molecules present lipid antigens, oftentimes to 2 other distinct families of T-cells: gammadelta T-cells (named because they bear a T-cell antigen receptor consisting of a gamma chain and a delta chain rather than the alpha chain/beta chain heterodimer on most T-cells) and iNKT cells (T-cells that bear markers previously defined on natural killer cells). CD1 molecules and the gammadelta T-cells and iNKT cells to which they present antigens have fundamental responsibilities for immune surveillance over intracellular pathogens and serve other roles that place them at the boundary between innate and acquired immunity. The gammadelta T-cell has been implicated in the pathogenesis of many diseases, rheumatologic and otherwise, suggesting that better understanding of these cells, and of CD1 molecules, may help us explain the immunopathogenesis of some inflammatory diseases and how to craft more targeted therapies in many fields of medicine.

Antigens, CD1↗
PubMed1999

Density and molecular epidemiology of Aspergillus in air and relationship to outbreaks of Aspergillus infection.

After five patients were diagnosed with nosocomial invasive aspergillosis caused by Aspergillus fumigatus and A. flavus, a 14-month surveillance program for pathogenic and nonpathogenic fungal conidia in the air within and outside the University Hospital in Rotterdam (The Netherlands) was begun. A. fumigatus isolates obtained from the Department of Hematology were studied for genetic relatedness by randomly amplified polymorphic DNA (RAPD) analysis. This was repeated with A. fumigatus isolates contaminating culture media in the microbiology laboratory. The density of the conidia of nonpathogenic fungi in the outside air showed a seasonal variation: higher densities were measured during the summer, while lower densities were determined during the fall and winter. Hardly any variation was found in the numbers of Aspergillus conidia. We found decreasing numbers of conidia when comparing air from outside the hospital to that inside the hospital and when comparing open areas within the hospital to the closed department of hematology. The increase in the number of patients with invasive aspergillosis could not be explained by an increase in the number of Aspergillus conidia in the outside air. The short-term presence of A. flavus can only be explained by the presence of a point source, which was probably patient related. Genotyping A. fumigatus isolates from the department of hematology showed that clonally related isolates were persistently present for more than 1 year. Clinical isolates of A. fumigatus obtained during the outbreak period were different from these persistent clones. A. fumigatus isolates contaminating culture media were all genotypically identical, indicating a causative point source. Knowledge of the epidemiology of Aspergillus species is necessary for the development of strategies to prevent invasive aspergillosis. RAPD fingerprinting of Aspergillus isolates can help to determine the cause of an outbreak of invasive aspergillosis.

Air Microbiology↗
PubMed2004

Differential expression of SHIP1 in CD56bright and CD56dim NK cells provides a molecular basis for distinct functional responses to monokine costimulation.

Monocyte cytokines (ie, monokines) induce natural killer (NK) cells to produce interferon-gamma (IFN-gamma), which is critical for monocyte clearance of infectious pathogens and tumor surveillance. Human CD56bright NK cells produce far more IFN-gamma in response to monokines than do CD56dim NK cells. The kinases and phosphatases involved in regulating IFN-gamma production by monokine-activated NK cells are not clearly identified. SHIP1 is a 5' inositol phosphatase that dephosphorylates the phosphatidylinositol-3 kinase (PI-3K) product PI3,4,5P3. Here, we show that constitutive expression of SHIP1 is distinctly lower in CD56bright NK cells compared with CD56dim NK cells, suggesting it could be an important negative regulator of IFN-gamma production in monokine-activated NK cells. Indeed, overexpression of SHIP1 in CD56bright NK cells followed by monokine activation substantially lowered IFN-gamma production. This effect was not seen when NK cells were infected with a SHIP1 mutant containing an inactive catalytic domain. Finally, NK cells in SHIP1-/- mice produced more IFN-gamma in response to monokines in vivo than did NK cells from wild-type mice. Collectively, these results demonstrate that SHIP1 negatively regulates monokine-induced NK cell IFN-gamma production in vitro and in vivo and provide the first molecular explanation for an important functional distinction observed between CD56bright and CD56dim human NK subsets.

Animals↗
PubMed2006

Detection and molecular characterization of group A rotavirus from hospitalized children in Rio de Janeiro, Brazil, 2004.

Rotavirus is a major cause of infantile acute diarrhea, causing about 440,000 deaths per year, mainly in developing countries. The World Health Organization has been recommending the assessment of rotavirus burden and strain characterization as part of the strategies of immunization programs against this pathogen. In this context, a prospective study was made on a sample of 134 children with acute diarrhea and severe dehydration admitted to venous fluid therapy in two state hospitals in Rio de Janeiro, Brazil, from February to September 2004. Rotavirus where detected by polyacrylamide gel electrophoresis (PAGE) and by an enzyme-linked immunoassay to rotavirus and adenovirus (EIARA) in 48% of the children. Positive samples for group A rotavirus (n = 65) were analyzed by reverse transcription/heminested multiplex polymerase chain reaction to determine the frequency of G and [P] genotypes and, from these, 64 samples could be typed. The most frequent G genotype was G1 (58%) followed by G9 (40%). One mixed infection (G1/G9) was detected. The only [P] genotype identified was [8]. In order to estimate the rotavirus infection frequency in children who acquired diarrhea as hospital infection in those hospitals, we studied 24 patients, detecting the pathogen in 41% of them. This data suggest that genotype G9 is an important genotype in Rio de Janeiro, with implications to the future strategies of vaccination against rotavirus, reinforcing the need of continuous monitoring of circulating strains of the pathogen, in a surveillance context.

Acute Disease↗
PubMed2004

[Antimicrobial susceptibility of the bloodstream infections: a study in a nonteaching hospital].

BACKGROUND: To try established antimicrobial susceptibility patterns and frequency of both nosocomial and community-acquired bloodstream infections and and to try identified the prognostic factors that can be modified. MATERIAL AND METHODS: A prospective study of 310 bloodstream infections with clinical significance detected in a non teaching hospital over period from October 2000-2001. A blood culture were identified by Bact-Alert system and the confirmation was performed by MicroScan system; an antimicrobial susceptibility test was performed by reference microdilution methods as described by NCCLS. We studied sentinel antimicrobial/organism combinations with potential clinical importance. Data were computerized using SPSS. Qualitative variables were compared using the X2 test or the Fisher exact test, and quantitative variables with t Student or ANOVA. RESULTS: Gram positive and Candida were frequently recovered in nosocomial bloodstreams. The proportion of oxacillin-resistant S. aureus isolates was 24% and the penicillin resistant pneumococci was 14%. Vancomycin was universal active against gram positive. Gram negatives were often recovered in community bloodstream. The proportion of EBSL E. coli isolates was < 2% and the proportion of multiresistance Pseudomonas aeruginosa was higher among UCI isolates. An independent risk factors for death identified after multivariate analysis was the inappropriate antimicrobial therapy OR 2.6. CONCLUSIONS: Ongoing surveillance of microbial pathogens and their resistance profiles is essential on local scale and permit the selection of appropriate antibiotic therapy which would be reduce the mortality.

Drug Resistance, Microbial↗
PubMed2002

Foodborne infectious risks: do we need a wide system of data collection and survey? The lessons learned from the study of infectious intestinal disease in England.

In 2000, the United Kingdom Government's Food Standards Agency published "A report of the study of infectious intestinal disease in England". This report was the result of over a decade's endeavour and cost well in excess of 2 million pound sterling (approximately 3.3 million euros). The study originated in 1989. In response to national epidemics of foodborne infection with Salmonella enteritidis phage type 4 and Listeria monocytogenes, the Government set up the Committee on the Microbiological Safety of Food (the Richmond Committee). This committee wished to know the actual level of clinical disease in the population giving rise to the laboratory reports of gastro-intestinal pathogens in national surveillance data and recommended studies to achieve this objective. In addition, successors to the to Richmond Committee decided that it would be of value to collect information from both cases and controls, including documenting exposure to biologically plausible risk factors so that differences between the ill and the well could be identified. Enquiries were also made about the clinical course of disease, so that long term sequelae and socio-economic costs could be estimated. A full description of this enormous study is beyond the scope of this paper, which defends the personal view that resources might have been better spent on a less ambitious enquiry.

Case-Control Studies↗
PubMed1990

[The effect of selective decontamination on nosocomial infections, their causative agents and antibiotic resistance in long-term intubated intensive care patients].

During a 12-month period 45 long-term intubated patients were treated by topical application of non-absorbable antibiotics (tobramycin, polymyxin, amphotericin B) together with an initial short-term intravenous application of an antibiotic with only minimal activity against anaerobic intestinal flora. These patients were compared to 48 patients in the previous 12-month period who had only interventional antibiotic therapy in case of established infections. This selective decontamination of the digestive tract (SDD) reduced the colonisation of the respiratory tract, thus also decreasing incidence of nosocomial pneumonia. There were fewer urinary tract infections, while the incidence of wound infections and septicaemia was influenced to microorganism a lesser degree. The number of gram-negative isolated microorganism was reduced, leading to a shift towards gram-positive organisms, especially S. epidermidis. During the 12-month study period there was no change of antibiotic sensitivity of the isolated microorganisms. Although we encountered no problems associated with multiresistant pathogens, routine microbiological surveillance is strongly recommended to detect changes in antibiotic resistance at an early stage.

Administration, Topical↗
PubMed1998

An outbreak of Salmonella agona infection associated with precooked turkey meat.

An outbreak of Salmonella agona phage type (PT) 15 infection in North Staffordshire in September 1996 was associated with consumption of precooked turkey meat. The shops from which five of the six cases had bought turkey meat were supplied by the same distributor. S. agona phage type 15 was isolated from nine cases, from cooked turkey sampled from a shop, and from an unopened cryovacuumed packed joint at the supplier's premises. Environmental investigations at a food manufacturer's premises revealed deficiencies in cooking practices. Microbiological investigations at those premises on samples (food, environmental swabs) taken two to three weeks after the cases became ill were negative. The rarity of S. agona brought this outbreak to our attention and the successful identification of a vehicle of infection demonstrated the value of local surveillance of gastrointestinal pathogens and of good working relationships between public health and local authority staff. The prompt voluntary withdrawal of suspect product probably prevented further cases.

Adult↗