Clinical and microbiological characteristics of community-onset Clostridium difficile infection in The Netherlands.

To elucidate the prevalence, characteristics and risk factors of community-onset Clostridium difficile infection (CO-CDI), an uncontrolled prospective study was performed. For 3 months in 2007-2008, three laboratories in The Netherlands tested all unformed stool samples submitted by general practitioners (GPs) for C. difficile by enzyme immunoassay for toxins A and B, irrespective of whether GPs specifically requested this. Patients with positive results were asked to complete a questionnaire. Positive stool samples were cultured for C. difficile, and isolates were characterized. In all, 2443 stool samples from 2423 patients were tested, and 37 patients (1.5%) with positive toxin test results were identified. Mixed infections were not found. Age varied from 1 to 92 years, and 18% were under the age of 20 years. Diarrhoea was typically frequent and watery, sometimes with admixture of blood or fever. Eight of 28 patients (29%) suffered recurrences. Among 31 patients with toxin-positive stool samples for whom information was available, 20 (65%) had not been admitted to a healthcare institution in the year before, 13 (42%) had not used antibiotics during the 6 months before, and eight (26%) had neither risk factor. A separate analysis for patients whose samples were both toxin-positive and culture-positive produced similar results. Cultured C. difficile isolates belonged to 13 different PCR ribotypes, and 24% of the isolates were non-typeable (rare or new) PCR ribotypes. In conclusion, CO-CDI can affect all age groups, and many patients do not have known risk factors. Several PCR ribotypes not encountered in hospital-associated outbreaks were found, suggesting the absence of a direct link between outbreaks and community-onset cases.

Inhibition of Semliki Forest virus multiplication in L-cells by combinations of interferon and ribavirin as measured by plaque titration and direct enzyme immunoassay.

Inhibition of Semliki Forest virus (SFV) multiplication in L-cell monolayers by combinations of mouse interferon (IFN) and ribavirin was measured by plaque titration and by direct enzyme immunoassay of SFV in L-cells. When critically inhibitory quantities of IFN and ribavirin were combined, an additive inhibitory effect was observed in either assay.

Effect of selective decontamination of the digestive tract of donor and recipient on the occurrence of murine delayed-type graft-versus-host disease.

In the present study we investigated the occurrence of delayed-type graft-versus-host disease (DT-GvHD) after allogeneic bone marrow transplantation (BMT) between two H-2 incompatible mouse strains. BMT was performed on mice with a conventional intestinal microflora as well as on mice in which the Enterobacteriaceae were selectively eliminated from the intestinal microflora by oral antibiotic treatment. None of the conventional or the selectively decontaminated (SD) chimaeric mice suffering from DT-GvHD died of bacteraemia. While DT-GvHD was mitigated when C3H/He recipient mice were SD-treated, this was not the case when C57B1/6J recipient mice were SD-treated. SD-treatment of the digestive tract of donor mice only mitigated DT-GvHD when the recipients were also SD-treated. We conclude that Enterobacteriaceae in the digestive tract may only play a minor role, if any, in the occurrence of DT-GvHD. Instead, we postulate that in this study DT-GvHD was determined by differences in the composition of the resident intestinal microflora (IM) of both mouse strains together with the cellular composition of the bone marrow graft. The interaction between antigenic components of the recipient's IM and the developing donor immune system in the recipient as a possible cause for DT-GvHD is discussed.

Application of immunoassay of encephalomyocarditis virus in cell culture with enzyme-labeled virus-specific monoclonal antibodies for rapid detection of virus, neutralizing antibodies, and interferon.

Encephalomyocarditis virus (EMCV)-specific monoclonal antibody UM 21.1 labeled with horseradish peroxidase was used to detect EMCV in L-cell monolayers. This direct enzyme immunoassay of EMCV, performed in wells of 96-well plates, could be applied for various purposes, such as early detection of virus multiplication, determination of 50% tissue culture infective doses, and rapid titration of interferon and EMCV-neutralizing antibodies. Multiplication of EMCV is indicated by a rapid increase of the absorbance values measured against EMCV-infected L cells starting as early as 4.5 h after virus inoculation. The early rise of absorbance (i.e., virus multiplication) is inhibited by interferon, allowing its rapid titration. Preincubation of the virus inoculum with neutralizing antibodies also yielded decreased absorbance values. With the latter enzyme immunoassay for neutralizing antibodies, performed after an infection period of 8 h, antibody titers measured were comparable to those obtained with a conventional plaque reduction test. We assume that similar assays could be developed for other picornaviruses (e.g., polioviruses).

Salmonella panama osteomyelitis in an otherwise healthy patient. A case report.

A 22-year-old man had Salmonella panama osteomyelitis of the left distal tibia. He had endured a period of untreated diarrhea without fever 6 years before. The osteomyelitis was treated successfully with surgical debridement followed by 9 weeks of oral cotrimoxazole 960 mg twice daily. Salmonella osteomyelitis is rare. Most cases occur in patients with sickle cell anemia. Other conditions of local or generalized immunosuppression are also risk factors, but none were established in this patient, nor was he a chronic carrier. In reviewing the literature, no case of Salmonella panama osteomyelitis in an otherwise healthy patient was found. Although the osteomyelitis in this patient was possibly secondary to Salmonella enteritis 6 years before, the authors believe that enteric Salmonella infections should not be treated with antibiotics unless the infection is accompanied by systemic symptoms. Otherwise, the risk of chronic carriership is substantially increased. In case of Salmonella panama osteomyelitis, surgical debridement is recommended as the main component of treatment, followed by a prolonged period of specific antibiotic therapy.

Micromorphometrical analysis of rodent related (SPF) and unrelated (human) gut microbial flora in germfree mice by digital image processing.

Digital image processing (DIP) of bacterial smears is a new method of analysing the composition of the gut microbial flora. This method provides the opportunity to compare and evaluate differences in the complex highly concentrated anaerobic fraction of gut microbial flora, based on micromorphological differences. There is ample evidence that this fraction can be characterized as related or unrelated to the host organism by its immunogenicity. In this study germfree ND2 mice were associated with either related (rodent) SPF microflora (SPF-MF) or unrelated human MF (HUM-MF). DIP analysis was performed on original SPF-MF and HUM-MF and on the faeces of ex-germfree mice 4 weeks after association. The micromorphological pattern of highly concentrated anaerobic bacteria in faeces of HUM-MF associated ex-germfree mice was significantly different from SPF-MF associated counterparts with regard to the scores for elongation (P < 0.01) and morphological variety (P < 0.05). Moreover, gross morphological variability was present between individual HUM-MF associated mice but not between individual SPF-MF associated animals. No differences were found between original SPF and HUM-MF. The data are discussed with regard to differences in the presence of (non-)immunogenic bacteria and the ability for related and unrelated flora to colonize the murine gut. This study provides evidence that murine host specificity of microbial flora may not only be reflected in the number of non-immunogenic bacteria but also in the micromorphological pattern of highly concentrated anaerobic bacteria in faeces measured by DIP analysis.