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Stuart Johnson

Publications and source records attributed to Stuart Johnson.

15 recordsLinked to original sources
PubMed2005

Revised nomenclature of Clostridium difficile toxins and associated genes.

Several different nomenclatures have been applied to the Clostridium difficile toxins and their associated genes. This paper summarizes the new nomenclature that has been agreed to by the research groups currently active in the field. The revised nomenclature includes C. difficile toxins and other related large clostridial toxins produced by Clostridium sordellii and Clostridium novyi, and corresponding toxin genes, as well as toxin production types of C. difficile strains.

Bacterial Proteins↗
PubMed2004

Staphylococcus aureus and Clostridium difficile cause distinct pseudomembranous intestinal diseases.

We report simultaneous infections with Clostridium difficile and methicillin-resistant Staphylococcus aureus (MRSA) in a patient with discrete colonic pseudomembranes typical of C. difficile infection, as well as confluent, loosely adherent pseudomembranes in the small bowel. Identification of MRSA in the small bowel pseudomembrane by polymerase chain reaction supports S. aureus as an enteric pathogen.

Clostridioides difficile↗
PubMed2004

Serious adverse cutaneous and hepatic toxicities associated with nevirapine use by non-HIV-infected individuals.

BACKGROUND: Nevirapine is a nonnucleoside reverse transcriptase antiretroviral agent. Among HIV-infected individuals, rare instances (<1%) of serious cutaneous and hepatic toxicity have been reported. Because of its favorable pharmacokinetic profile, non-HIV-infected individuals have received nevirapine-containing postexposure prophylaxis (PEP). OBJECTIVE: To describe the clinical features of cutaneous and hepatic toxicity that occurred when nevirapine was administered to non-HIV-infected individuals. METHODS: Reports of nevirapine-associated cutaneous or hepatic toxicity occurring among non-HIV-infected individuals were obtained from the US Food and Drug Administration's adverse event reporting system, the pharmaceutic manufacturer, occupational health programs in Chicago, physicians, and case reports. The Eastern Cooperative Oncology Group (ECOG) scoring system was used to grade toxicity. RESULTS: Twelve non-HIV-infected individuals developed severe cutaneous toxicity, including 3 with Stevens-Johnson syndrome, after 7 to 12 days of nevirapine-containing PEP regimens. Thirty non-HIV-infected individuals developed hepatotoxicity after 8 to 35 days of single-agent nevirapine (n = 8) or a nevirapine-containing PEP regimen (n = 22). Findings included ECOG grade 3 or 4 hepatotoxicity (n = 14), fevers (n = 11), skin rashes (n = 8), eosinophilia (n = 6), and fulminant hepatic necrosis requiring an orthotopic liver transplant (n = 1). Rates of severe hepatotoxicity (grade 3 or 4) in non-HIV-infected individuals ranged from 10% (4/41) to 62% (5/8). Liver biopsy material from 2 individuals was consistent with a hypersensitivity syndrome. CONCLUSIONS: Serious hepatic and cutaneous toxicities can occur in non-HIV-infected individuals who receive short-term nevirapine therapy. The rate of severe hepatotoxicity appears to be greater in non-HIV-infected individuals than in HIV-infected persons and may be associated with higher CD4 counts. The use of PEP regimens containing nevirapine should be discouraged.

Adult↗
PubMed2004

Tuberculous tenosynovitis.

Tuberculous tenosynovitis is rare and may be overlooked as a cause of chronic tenosynovitis. This report presents a case of a young woman with tuberculosis tenosynovitis of the wrist, and highlights the clinical, imaging, histological, and laboratory features most commonly seen in this disease.

Adult↗
PubMed2004

Distribution of Clostridium difficile variant toxinotypes and strains with binary toxin genes among clinical isolates in an American hospital.

Genetic variants of Clostridium difficile have been reported with increasing frequency, but their true incidence is unknown. C. difficile strains have been classified into variant toxinotypes according to variations in the pathogenicity locus encoding the major virulence factors, toxins A and B. Some strains produce an additional toxin, binary toxin CDT. This survey of clinical isolates (153) from patients in a single hospital set out to ascertain the distribution of variant toxinotypes and strains possessing binary toxin genes. A PCR-RFLP-based method of toxinotyping identified 123 (80.4 %) isolates as toxinotype 0, 13 (8.5 %) strains as non-toxigenic and 17 (11.1 %) as belonging to variant toxinotypes. Binary toxin genes were amplified by PCR in nine strains (5.8 %), all of which were variant toxinotypes. Toxin variants of C. difficile are pathogenic and commonly isolated and need to be considered when evaluating new diagnostic testing strategies for C. difficile disease.

ADP Ribose Transferases↗
PubMed2003

Prevention of fatal Clostridium difficile-associated disease during continuous administration of clindamycin in hamsters.

Clostridium difficile-associated disease (CDAD) due to toxigenic strains is prevented in hamsters by colonization by nontoxigenic C. difficile after administration of clindamycin (Cm). To prevent CDAD during treatment with antibiotics, we gave a Cm-resistant nontoxigenic C. difficile strain, M13 (minimal inhibitory concentration [MIC], >256 microg/mL), and a Cm-susceptible strain, M3 (MIC, 0.5 microg/mL), to hamsters receiving Cm daily for days 1-5. Either M13 or M3 was given orogastrically (1 x 10(6) spores/day) to each hamster in 3 groups of 5 each, on either day 3, days 3-5, or days 3-7. M13 colonized at a higher rate and faster than did M3 (P<.001). When hamsters were challenged by toxigenic strain B1 on days 5, 7, or 9, M13 prevented CDAD in 100% of the hamsters. M3 protected no hamsters challenged by B1 on day 5, 20% on day 7, and 100% on day 9. M13 contains the erm(B) resistance gene but not the mobilizable element Tn5398. The benefits of use of Cm-resistant nontoxigenic C. difficile to prevent CDAD must be balanced against the risk that resistance might be transferred to other enteric bacteria.

Adhesins, Bacterial↗
PubMed2003

Pseudo-SARS.

Explore the source record for details and available documents.

Adult↗
PubMed2003

Eosinophilic Meningitis.

Eosinophilic meningitis (EM) is a distinct clinical entity that may have infectious and noninfectious causes. Worldwide, infection with the helminthic parasite, Angiostrongylus cantonensis, is the most common infectious etiology. Historically, this infection has been acquired through ingestion of competent intermediate and paratenic (carrier) hosts or contaminated food in Southeast Asia and the Pacific Islands. A recent outbreak of A. cantonensis-associated EM among US travelers to Jamaica and subsequent parasitologic surveys of local snails and rats confirm earlier case reports and engender a wider appreciation of the Caribbean islands as a new region for endemic A. cantonensis infections. Clinically, eosinophilia is not always present in the cerebrospinal fluid or in the peripheral blood during the initial manifestions of A. cantonensis-associated EM, which include headache and cutaneous sensory alterations. Effective management of patients involves careful attention to the control of intracranial pressure. Steroid therapy without specific anthelmintic treatment is safe and effective in control of headache of adult patients with A. cantonensis-associated EM.

Journal Article↗
PubMed2003

Frequency of binary toxin genes among Clostridium difficile strains that do not produce large clostridial toxins.

Pathogenic strains of Clostridium difficile commonly produce two large clostridial toxins (LCTs), A and B, virulence factors responsible for C. difficile disease. Some strains have been reported to produce an additional toxin, a binary toxin designated CDT. Binary toxin has cytotoxic effects on cells in culture, but its role in human disease is not yet defined. In this study we examined the frequency of binary toxin genes (cdtB and cdtA) among C. difficile isolates that do not produce LCTs (A(-) B(-)) from a large United States-based collection organized by restriction endonuclease analysis (REA) typing. Of 58 strains tested, 9 (15.5%) were cdtB and cdtA positive, including 4 of 46 (8.7%) non-LCT-producing REA groups, with an estimated prevalence of at least 2% of all non-LCT-producing isolates within the collection. Five of the binary toxin-positive strains belonged to toxinotype XI, which does not produce LCTs but has minor parts of the LCT coding region or pathogenicity locus (PaLoc). We describe two new binary toxin-positive variants, one without any remnant of the LCT genes. This previously unknown variation was found in three isolates that were unrelated by REA typing. LCT-negative, binary toxin-positive strains were isolated from symptomatic and asymptomatic patients and from the hospital environment.

ADP Ribose Transferases↗
PubMed2003

International typing study of toxin A-negative, toxin B-positive Clostridium difficile variants.

Clinically important strains of Clostridium difficile that do not produce toxin A but produce toxin B and are cytotoxic (A(-)/B(+)) have been reported from multiple countries. In order to compare the relatedness of these strains, we typed 23 A(-)/B(+) C. difficile isolates from the United Kingdom (6 isolates), Belgium (11 isolates), and the United States (6 isolates) by three well-described typing methods. Restriction endonuclease analysis (REA), PCR ribotyping, and serogrouping differentiated 11, 4, and 3 different strain types, respectively. Twenty-one of the 23 A(-)/B(+) variants had a 1.8-kb truncation of the toxin A gene characteristic of toxinotype VIII strains; 20 of the 21 toxinotype VIII-like strains were PCR type 17. PCR type 17 isolates could be differentiated into two separate strain groups by serogrouping and by REA. REA further discriminated these isolates into eight subgroups (REA types). PCR type 17-serogroup F-REA group CF isolates were recovered from all three countries, and one specific REA type, CF4, was recovered from patients with C. difficile disease in the United Kingdom and the United States. C. difficile A(-)/B(+) variants of apparent clonal origin are widely distributed in Europe and North America.

Adult↗
PubMed2003

Fatal case of endocarditis due to Weissella confusa.

This is the first reported case of endocarditis due to the Lactobacillus-like vancomycin-resistant gram-positive bacillus Weissella confusa. Full identification and susceptibility testing of Lactobacillus-like organisms recovered in blood culture should be performed for patients with clinical presentations that suggest endocarditis.

Base Sequence↗
PubMed2002

Colonization for the prevention of Clostridium difficile disease in hamsters.

Studies suggest that asymptomatic colonization with Clostridium difficile (CD) decreases the risk of CD-associated disease (CDAD) in humans. A hamster model was used to test the efficacy of colonization with 3 nontoxigenic CD strains for preventing CDAD after exposure to toxigenic CD. Groups of 10 hamsters were given 10(6) nontoxigenic CD spores 2 days after receiving a single dose of clindamycin. Five days later, the hamsters were given 100 spores of 1 of 3 toxigenic CD strains previously shown to cause mortality within 48 h. Each nontoxigenic strain prevented disease in 87%-97% of hamsters that were challenged with toxigenic strains. Failure to prevent CDAD was associated with failure of colonization with nontoxigenic CD. Colonization with nontoxigenic CD strains is highly effective in preventing CDAD in hamsters challenged with toxigenic CD strains, which suggests that use of a probiotic strategy for CDAD prevention in humans receiving antibiotics might be beneficial.

Animals↗
PubMed2002

An outbreak of eosinophilic meningitis caused by Angiostrongylus cantonensis in travelers returning from the Caribbean.

BACKGROUND: Outbreaks of eosinophilic meningitis caused by the roundworm Angiostrongylus cantonensis are rarely reported, even in regions of endemic infection such as Southeast Asia and the Pacific Basin. We report an outbreak of A. cantonensis meningitis among travelers returning from the Caribbean. METHODS: We conducted a retrospective cohort study among 23 young adults who had traveled to Jamaica. We used a clinical definition of eosinophilic meningitis that included headache that began within 35 days after the trip plus at least one of the following: neck pain, nuchal rigidity, altered cutaneous sensations, photophobia, or visual disturbances. RESULTS: Twelve travelers met the case definition for eosinophilic meningitis. The symptoms began a median of 11 days (range, 6 to 31) after their return to the United States. Eosinophilia was eventually documented in all nine patients who were hospitalized, although on initial evaluation, it was present in the peripheral blood of only four of the nine (44 percent) and in the cerebrospinal fluid of five (56 percent). Repeated lumbar punctures and corticosteroid therapy led to improvement in symptoms in two of three patients with severe headache, and intracranial pressure decreased during corticosteroid therapy in all three. Consumption of one meal (P=0.001) and of a Caesar salad at that meal (P=0.007) were strongly associated with eosinophilic meningitis. Antibodies against an A. cantonensis--specific 31-kD antigen were detected in convalescent-phase serum samples from 11 patients. CONCLUSIONS: Among travelers at risk, the presence of headache, elevated intracranial pressure, and pleocytosis, with or without eosinophilia, particularly in association with paresthesias or hyperesthesias, should alert clinicians to the possibility of A. cantonensis infection.

Adrenal Cortex Hormones↗
PubMed2002

Predominance of a single restriction endonuclease analysis group with intrahospital subgroup diversity among Clostridium difficile isolates at two Chicago hospitals.

OBJECTIVE: To determine the epidemiology and relatedness of Clostridium difficile isolates in two geographically separated hospitals in a large metropolitan area, each with unique patients and personneL DESIGN: Observational descriptive molecular epidemiology of clinical C. difficile isolates. SETTING: Two tertiary-care hospitals in Chicago. METHODS: Consecutive C. difficile isolates from the clinical laboratory of a Veterans Affairs hospital during a 13-month period were typed by restriction endonuclease analysis (REA). During an overlapping 3-month period, stool specimens that tested positive for C. difficile toxin from patients at a nearby county hospital were cultured and the recovered isolates typed by the same method. RESULTS: Nineteen (68%) of 28 nosocomial isolates at the smaller, Veterans Affairs hospital belonged to REA group K. Within this group of closely related strains, 9 distinct REA types were recognized. Twenty-one (72%) of 29 nosocomial isolates at the larger, county hospital also belonged to group K. However, the predominant REA types within group K differed markedly at each institution. CONCLUSIONS: These findings demonstrate a high degree of similarity among nosocomial C. difficile strains from different hospitals in the same city and suggest the possibility of an extended outbreak of a prototype group K strain with subsequent genetic drift at the two different institutions.

Chicago↗