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Biomedical subjects

J M Embil

Publications and source records attributed to J M Embil.

At least 19 recordsLinked to original sources
PubMed2001

An outbreak of methicillin resistant Staphylococcus aureus on a burn unit: potential role of contaminated hydrotherapy equipment.

OBJECTIVE: To report a multi-institution outbreak caused by a single strain of methicillin-resistant Staphylococcus aureus (MRSA). OUTBREAK: Between September 19 and November 20, 1996 an index case and five secondary cases of nosocomial MRSA occurred on a 26 bed adult plastic surgery/burn unit (PSBU) at a tertiary care teaching hospital. Between November 11 and December 23, 1996, six additional cases were identified at a community hospital. One of the community hospital cases was transferred from the PSBU. All strains were identical by pulsed-field gel electrophoresis. MRSA may have contributed to skin graft breakdown in one case, and delayed wound healing in others. Patients required 2 to 226 isolation days. CONTROL MEASURES: A hand held shower and stretcher for showering in the hydrotherapy room of the PSBU were culture positive for the outbreak strain, and the presumed means of transmission. Replacement of stretcher showering with bedside sterile burn wound compresses terminated the outbreak. The PSBU was closed to new admissions and transfers out for 11 days during the investigation. Seven of 12 patients had effective decolonization therapy. CONCLUSION: Environmental contamination is a potential source of nosocomial MRSA transmission on a burn unit. Notification among institutions and community care providers of shared patients infected or colonized with an antimicrobial resistant microorganism is necessary.

Adult↗
PubMed2001

Calcific myonecrosis: case report and review.

Although a rare diagnosis, with few reports in the literature, calcific myonecrosis is a diagnosis that must be entertained in individuals presenting with expanding masses in the muscle compartments occurring years after an initial injury. The authors report a previously healthy 66-year-old man with an expanding right lower extremity mass felt initially to be an abscess. Despite presumably appropriate antimicrobial therapy, the lesion continued to expand, causing pain and loss of function. The patient subsequently underwent extensive debridement and free muscle flap transfer with an excellent outcome. This patient serves to remind us that, although calcific myonecrosis is an uncommonly encountered condition, it must be maintained in the differential diagnosis of an expanding muscle compartment mass.

Aged↗
PubMed2001

Review of macrolides and ketolides: focus on respiratory tract infections.

The first macrolide, erythromycin A, demonstrated broad-spectrum antimicrobial activity and was used primarily for respiratory and skin and soft tissue infections. Newer 14-, 15- and 16-membered ring macrolides such as clarithromycin and the azalide, azithromycin, have been developed to address the limitations of erythromycin. The main structural component of the macrolides is a large lactone ring that varies in size from 12 to 16 atoms. A new group of 14-membered macrolides known as the ketolides have recently been developed which have a 3-keto in place of the L-cladinose moiety. Macrolides reversibly bind to the 23S rRNA and thus, inhibit protein synthesis by blocking elongation. The ketolides have also been reported to bind to 23S rRNA and their mechanism of action is similar to that of macrolides. Macrolide resistance mechanisms include target site alteration, alteration in antibiotic transport and modification of the antibiotic. The macrolides and ketolides exhibit good activity against gram-positive aerobes and some gram-negative aerobes. Ketolides have excellent activity versus macrolide-resistant Streptococcus spp. Including mefA and ermB producing Streptococcus pneumoniae. The newer macrolides, such as azithromycin and clarithromycin, and the ketolides exhibit greater activity against Haemophilus influenzae than erythromycin. The bioavailability of macrolides ranges from 25 to 85%, with corresponding serum concentrations ranging from 0.4 to 12 mg/L and area under the concentration-time curves from 3 to 115 mg/L x h. Half-lives range from short for erythromycin to medium for clarithromycin, roxithromycin and ketolides, to very long for dirithromycin and azithromycin. All of these agents display large volumes of distribution with excellent uptake into respiratory tissues and fluids relative to serum. The majority of the agents are hepatically metabolised and excretion in the urine is limited, with the exception of clarithromycin. Clinical trials involving the macrolides are available for various respiratory infections. In general, macrolides are the preferred treatment for community-acquired pneumonia and alternative treatment for other respiratory infections. These agents are frequently used in patients with penicillin allergies. The macrolides are well-tolerated agents. Macrolides are divided into 3 groups for likely occurrence of drug-drug interactions: group 1 (e.g. erythromycin) are frequently involved, group 2 (e.g. clarithromycin, roxithromycin) are less commonly involved, whereas drug interactions have not been described for group 3 (e.g. azithromycin, dirithromycin). Few pharmacoeconomic studies involving macrolides are presently available. The ketolides are being developed in an attempt to address the increasingly prevalent problems of macrolide-resistant and multiresistant organisms.

Adolescent↗
PubMed2001

Necrotizing fasciitis.

Necrotizing fasciitis is a devestating condition which has been recognized for several years. In North America a recent increase of cases has led to much media attention and public fear. Necrotizing fasciitis may occur as a consequence of infection with Streptococcus pyogenes or as a result of a polymicrobial synergistic infection caused by aerobic, anaerobic, gram positive and gram negative organisms, often in postoperative patients. Necrotizing fasciitis caused by Streptococcus pyogenes is mediated by superantigens. The management of necrotizing fasciitis requires a high index of suspicion for diagnosis followed by antimicrobial therapy and early surgical intervention. In cases caused by Streptococcus pyogenes with streptococcal toxic shock syndrome, intravenous immunoglobulin may be of benefit.

Diagnosis, Differential↗
PubMed2000

Nocardia asteroides cerebral abscess in immunocompetent hosts: report of three cases and review of surgical recommendations.

BACKGROUND: Nocardia asteroides cerebral abscesses are rare intracranial lesions. They account for only 2% of brain abscesses. Existing literature takes the form of anecdotal reports, small case series, and retrospective studies. An optimal treatment approach has not been established. However, there is evidence that the size of the lesion and clinical and immune status of the patient are relevant to surgical decision making. METHODS: Three recent cases are presented and the existing literature is reviewed. RESULTS: The outcome in all three cases was satisfactory. Although the currently recommended neurosurgical management protocols were followed, one patient had a prolonged course, which may have been shortened had an earlier biopsy of the cerebral lesion been performed. CONCLUSIONS: The surgical approach to suspected Nocardia spp. cerebral abscesses has recently become less aggressive. A more aggressive approach than that currently preferred for suspected Nocardia spp. cerebral abscesses may be appropriate. Earlier biopsy of lesions to achieve specific identification and anti-microbial sensitivity profiles is suggested even in cases where an extracranial focus of infection is found. Delays in obtaining a biopsy may lead to non-specific or unhelpful results that may prolong the course in hospital and jeopardize the outcome.

Adult↗
PubMed2000

Characterization of a toxin A-negative, toxin B-positive strain of Clostridium difficile responsible for a nosocomial outbreak of Clostridium difficile-associated diarrhea.

Clostridium difficile-associated diarrhea (CAD) is a very common nosocomial infection that contributes significantly to patient morbidity and mortality as well as to the cost of hospitalization. Previously, strains of toxin A-negative, toxin B-positive C. difficile were not thought to be associated with clinically significant disease. This study reports the characterization of a toxin A-negative, toxin B-positive strain of C. difficile that was responsible for a recently described nosocomial outbreak of CAD. Analysis of the seven patient isolates from the outbreak by pulsed-field gel electrophoresis indicated that this outbreak was due to transmission of a single strain of C. difficile. Our characterization of this strain (HSC98) has demonstrated that the toxin A gene lacks 1.8 kb from the carboxy repetitive oligopeptide (CROP) region but apparently has no other major deletions from other regions of the toxin A or toxin B gene. The remaining 1.3-kb fragment of the toxin A CROP region from strain HSC98 showed 98% sequence homology with strain 1470, previously reported by M. Weidmann in 1997 (GenBank accession number Y12616), suggesting that HSC98 is toxinotype VIII. The HSC98 strain infecting patients involved in this outbreak produced the full spectrum of clinical illness usually associated with C. difficile-associated disease. This pathogenic spectrum was manifest despite the inability of this strain to alter tight junctions as determined by using in vitro tissue culture testing, which suggested that no functional toxin A was produced by this strain.

Adolescent↗
PubMed1999

Seroprevalence of Helicobacter pylori, incidence of gastric cancer, and peptic ulcer-associated hospitalizations in a Canadian Indian population.

The living conditions of many aboriginal communities in Canada may place their residents at risk for H. pylori infection. Our aims were to determine: (1) the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance of H. pylori infection in this population, and (3) if H. pylori could be identified by polymerase chain reaction from the local water. A demographic questionnaire was administered, and blood was collected from subjects in an Indian community in northwestern Manitoba. The serum was analyzed by ELISA for IgG to H. pylori and to CagA. ABO and Lewis antigens were tested. Age-adjusted incidence of gastric cancer and of hospitalizations associated with diagnoses of peptic ulcer were determined for the Indian and non-Indian Manitoba population in the years 1989-1993. Nested PCR was performed on lake water using H. pylori-specific primers and the amplicons probed with an internal Dig-labeled probe. Three hundred six (59%) of approximately 518 individuals who were resident in the community at the time of the study were enrolled. The ELISA for H. pylori was positive in 291 (95%). There was no association between H. pylori seropositivity and age, sex, gastrointestinal complaints, medications, housing characteristics, and ABO or Lewis antigen status. CagA was positive in 84.5% of infected subjects. The average annual age-adjusted incidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higher for treaty-status Indians (394.3/100,000) than for non-Indians (203.8/100,000), but gastric cancer rates were similar (11.2/100,000 vs 11.6/100,000). No H. pylori DNA was detected in the lake water. In conclusion, the seroprevalence of CagA-positive H. pylori is high in this representative Manitoban Indian community. This may be associated with an increased risk for peptic ulcer disease but is not associated with an increased risk for gastric cancer.

Adolescent↗
PubMed1999

Antimicrobial agents.

This article employs a comprehensive approach to review antimicrobial drugs, emphasizing the strengths and limitations of drugs including the traditional, those newly introduced and those currently under development. The significant issue of antimicrobial resistant organisms is addressed specifically.

Anti-Bacterial Agents↗