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Biomedical subjects

P A Meier

Publications and source records attributed to P A Meier.

12 recordsLinked to original sources

Influenza A in a basic training population: implications for directly observed therapy.

PURPOSE: To describe our evaluation of basic trainees exposed to influenza A and our experience with mass prophylaxis. METHODS: Using a structured interview, 101 individuals were evaluated for symptoms of influenza A. Nasopharyngeal wash specimens were obtained from symptomatic troops; amantadine prophylaxis was prescribed for all. Diagnosis was confirmed using a rapid influenza assay or shell vial culture. After completing prophylaxis, the group was reevaluated to determine medication compliance and perceived side effects. RESULTS: At baseline, 80 trainees reported symptoms. Three additional cases of influenza were identified, two using the rapid assay. Reported compliance with amantadine prophylaxis was 46.5%. CONCLUSIONS: Nonspecific complaints that could be consistent with viral infection were numerous in this basic trainee cohort. The rapid assay allowed us to expediently identify additional patients, who were then removed from the cohort to limit further transmission. Compliance with prophylaxis was poor; thus, directly observed therapy is recommended.

Aerospace Medicine↗

Pseudoepidemic of Aspergillus niger infections traced to specimen contamination in the microbiology laboratory.

We report a pseudo-outbreak of Aspergillus niger that followed building construction in our clinical microbiology laboratory. Because outbreaks of invasive aspergillosis have been linked to hospital construction, strategies to minimize dust in patient care areas are common practice. We illustrate that the impact of false-positive cultures on patient care should compel laboratories to prevent specimen contamination during construction.

Aspergillosis↗

Pseudo-outbreak of methicillin-resistant Staphylococcus aureus.

OBJECTIVE: To determine whether a high rate of methicillin-resistant Staphylococcus aureus at our institution was due to laboratory misclassification and to evaluate the effect of this misclassification. MATERIAL AND METHODS: We evaluated all S. aureus isolates identified at our institution during a 60-day period in 1997. Automated susceptibility test results (using the Vitek system) from our clinical microbiology laboratory and an independent laboratory were compared with oxacillin agar screen plate results at both laboratories. Isolates with discordant results for susceptibility to oxacillin were tested by broth microdilution minimal inhibitory concentrations and for the presence of the mecA gene. RESULTS: Eighteen (72%) of the 25 organisms (obtained from 17 patients) found to be resistant to oxacillin by the Vitek system at our institution were susceptible by the oxacillin agar screen. Discordant isolates tested by broth microdilution minimal inhibitory concentrations and for the mecA gene were found to be oxacillin susceptible and mecA gene negative. Thus, at our hospital, almost three fourths of the organisms initially identified as methicillin-resistant S. aureus by the Vitek system were actually susceptible to oxacillin. This misclassification resulted in needless infection control measures and unnecessary vancomycin use. CONCLUSION: Hospitals that use only automated susceptibility testing for S. aureus should periodically validate their results with additional testing.

Cross Infection↗

Coccidioidomycosis--the airborne assault continues: an unusual presentation with a review of the history, epidemiology, and military relevance.

Despite remarkable advances in detection and therapy, coccidioidomycosis remains a persistent threat to military troops deployed in endemic areas. Pregnant women, immunocompromised hosts, and dark-skinned persons, particularly those of Filipino, African, Hispanic or Asian ancestry, are at greatest risk for disseminated coccidioidomycosis. The ethnically diverse military forces have susceptible active duty and reserve members stationed at or temporarily trained on bases located in endemic areas for Coccidioides immitis. Although the vast majority of infections with this organism are subclinical, unusual patterns of dissemination pose a diagnostic challenge. The military physician may be tasked with recognizing acute non-specific symptoms as well as bizarre, occult manifestations of coccidioidomycosis. We present a case of disseminated coccidioidomycosis in an active duty Caucasian male who presented with a right shoulder mass. Our patient is atypical in that he had disseminated disease although immunocompetent and Caucasian. Another unusual feature is that the mass was not preceded or accompanied by any other symptoms. We could find only two other reported cases of coccidioidomycosis presenting as a soft tissue mass, both in African-American patients. The epidemiology and history of coccidioidomycosis will be reviewed, with an emphasis on military populations. The insidious nature of coccidioidomycosis, the importance of early detection and treatment in decreasing morbidity and mortality, and the presence of large numbers of military members in the endemic areas make the lessons of this case particularly relevant for all flight surgeons.

Adult↗

An epidemic of presumed Acanthamoeba keratitis that followed regional flooding. Results of a case-control investigation.

OBJECTIVES: To investigate an outbreak of presumed Acanthamoeba keratitis (AK), to identify risk factors associated with its development, and to characterize the changing epidemiology of AK. METHODS: We performed a pairwise-matched case-control study involving 31 patients who were diagnosed as having AK between July 1993 and December 1994. Risk factors were identified using conditional logistic regression analysis. To investigate the impact of regional flooding, we stratified counties within Iowa by whether their water facilities were affected and then calculated population-based estimates of the incidence of AK. RESULTS: During the study, 43 presumed incident cases of AK were diagnosed; 31 were included in the case-control study. Cases were diagnosed based on the clinical presentation of keratitis, positive tandem scanning confocal microscopy examination results, and confirmatory cytopathologic findings. There were no positive culture specimens. On average, cases had symptoms for 8 weeks before diagnosis, most notably photophobia (94%), red eyes (94%), and pain (80%). Contact lens use (odds ratio [OR] = 44.16; P = .02) and fishing (OR = 22.62; P = .04) were independent predictors of the development of AK. The presence of a humidifier in the home (OR = 0.08; P = .03) and having household water that originated from a private well instead of the municipal water supply (OR = 0.12; P = .08) were protective. Twenty-nine of 30 cases resided in counties in which the water supplies were affected by flooding as determined by the Department of Natural Resources, Des Moines, Iowa. The incidence of AK in these counties was more than 10 times higher than that in the unaffected counties (relative risk = 10.83, 95% confidence interval, 1.48-79.49; P < .003). CONCLUSIONS: We describe an epidemic of keratitis that, based on clinicopathologic and epidemiological evidence, is consistent with AK. As in previous outbreaks of culture-proven AK, contact lens use was the major risk factor. Both the results of the case-control study and the population-based incidence estimates suggest that the recent outbreak may be caused, in part, by the effects of regional flooding. However, because the outbreak also coincided with a change in diagnostic techniques, we cannot eliminate recognition bias as the reason for the apparently changing epidemiology.

Acanthamoeba Keratitis↗

Impact of a dedicated intravenous therapy team on nosocomial bloodstream infection rates.

BACKGROUND: Meticulous care of intravenous catheters could be expected to minimize associated nosocomial bloodstream infections, but care is often suboptimal. METHODS: To examine the ostensible benefits of a professional, dedicated intravenous therapy team, we compared the secular trends in nosocomial bloodstream infections before and after such a team was established. RESULTS: After the introduction of the team at the Veterans Administration Medical Center, the rate of primary nosocomial bloodstream infection decreased by 35% (1.1 to 0.7 infections/1000 patients-days, P < .01), including a 51% decrease in bloodstream infections caused by Staphylococcus aureus (P < .01). The excess cost of the team was $252,000 per year. The excess costs per life saved and infection prevented were projected to be $53,000 and $14,000, respectively. CONCLUSIONS: The introduction of a dedicated intravenous therapy team was associated with a significant reduction in nosocomial bloodstream infections. Further work is needed to maximize the cost-benefit ratio of this intervention.

Bacteremia↗

Development of quinolone-resistant Campylobacter fetus bacteremia in human immunodeficiency virus-infected patients.

Campylobacter fetus subspecies fetus has been recognized as a cause of systemic illness in immunocompromised hosts, including relapsing bacteremia in human immunodeficiency virus (HIV)-infected patients. Acquired resistance to quinolone therapy, while reported for a variety of bacteria, including Campylobacter jejuni, has not been previously documented for C. fetus. Two cases of quinolone-resistant C. fetus bacteremia were detected in HIV-infected patients. Cloning and nucleotide sequencing of the C. fetus gyrA gene in the 2 resistant isolates demonstrated a G-to-T change that led to an Asp-to-Tyr amino acid substitution at a critical residue frequently associated with quinolone resistance. In addition, comparison of the pre- and posttreatment isolates from 1 patient documented outer membrane protein changes temporally linked with the development of resistance. Relapsing C. fetus infections in quinolone-treated HIV-infected patients may be associated with the acquisition of resistance to these agents, and this resistance may be multifactorial.

AIDS-Related Opportunistic Infections↗

Cytomegalovirus polyradiculopathy in HIV-infected patients.

Cytomegalovirus polyradiculopathy, a late complication of HIV infection, is characterized by lower extremity weakness, urinary retention, and sacral dysesthesias. We describe four patients (mean CD4 T-cell count = 25 cells/mm3) who developed this "infectious cauda equina syndrome." The characteristic cerebrospinal fluid (CSF) findings, notably atypical for a viral infection, included polymorphonuclear leukocytosis (mean white blood cell count = 1512 cells/mm3, 72% polymorphonuclear leukocytes), elevated protein level (mean = 370 mg/dl), and hypoglycorrhacia (mean = 28 mg/dl). Physicians who treat patients with HIV should be familiar with this syndrome because early intervention, prior to microbiologic confirmation, provides the best hope for improving neurologic function.

AIDS-Related Opportunistic Infections↗

Outbreak of keratitis presumed to be caused by Acanthamoeba.

PURPOSE: A sharp increase of Acanthamoeba keratitis from two cases per year to 30 cases per year at our institution prompted this study to determine whether there was a change in the clinical characteristics, basic epidemiology, and outcome of this disease. METHODS: We reviewed all cases of Acanthamoeba keratitis diagnosed at the University of Iowa Hospitals and Clinics from mid-1993 through 1994. RESULTS: We screened 217 patients with keratitis by tandem scanning confocal microscopy and suspected Acanthamoeba in 51 patients. Diagnosis was confirmed by cytology in 43 patients (48 eyes). There were no positive cultures. Patients examined within four weeks of onset of symptoms were younger (mean age, 32.6 +/- 15.4 years) and wore contact lenses (11 of 18 patients), and infrequently herpes simplex keratitis (four of 18 patients) was diagnosed. Patients examined after four weeks were older (mean age, 54.0 +/- 19.5 years), infrequently wore contact lenses (six of 25 patients), and often had herpes simplex keratitis (12 of 25 patients). CONCLUSIONS: Corneal examination with tandem scanning confocal microscopy was associated with a marked increase in the detection of Acanthamoeba, strongly suggesting that the disease is more prevalent than suspected. Acanthamoeba may account for many cases of clinically presumed herpes simplex keratitis, the leading cause of corneal blindness in the United States. Acanthamoeba should be considered in the differential diagnosis of any unexplained keratitis, even those of short duration.

Acanthamoeba↗

A prolonged outbreak of methicillin-resistant Staphylococcus aureus in the burn unit of a tertiary medical center.

OBJECTIVE: To report an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in our burn unit and the steps we used to eradicate the organism. DESIGN AND SETTING: Outbreak investigation in the burn unit of a 900-bed tertiary-care medical center. OUTBREAK: Between March and June 1993, MRSA was isolated from 10 patients in our burn unit. All isolates had identical antibiograms and chromosomal DNA patterns. CONTROL MEASURES: Infection control personnel encouraged healthcare workers to wash their hands after each patients contact. The unit cohorted all infected or colonized patients, placed each affected patient in isolation, and, if possible, transferred the patient to another unit. Despite these measures, new cases occurred. Infection control personnel obtained nares cultures from 56 healthcare workers, 3 of whom carried the epidemic MRSA strain. One healthcare worker cared for six affected patients, and one cared for five patients. We treated the three healthcare workers with mupirocin. Subsequently, no additional patients became colonized or infected with the epidemic MRSA strain. CONCLUSIONS: The outbreak ended after we treated healthcare workers who carried the epidemic strain with mupirocin. This approach is not appropriate in all settings. However, we felt it was justified in this case because of a persistent problem after less intrusive measures.

Burn Units↗

Use of desmin immunohistochemistry to distinguish between mesothelial cells and carcinoma in serous fluid cell block preparations.

OBJECTIVE: To evaluate the utility of immunohistochemical stains for desmin in discriminating mesothelial cells from adenocarcinoma in serous fluid cell block preparations. STUDY DESIGN: Cell block preparations from 22 cases (representing 18 patients) that were positive for carcinoma and 5 cases that were negative for malignancy were immunostained with an antibody to desmin. Positive staining was evaluated and scored semiquantitatively in both tumor cells and background mesothelial cells in the malignant cases and mesothelial cells in the negative controls. Staining was evaluated with a score of 0-3 for intensity and 0-5 for distribution. The sum of the two scores was recorded as the total score (TS). RESULTS: Mesothelial cells from all the carcinoma and benign cases stained with desmin (median TS = 5.5, range 4-8), typically strong in intensity and widespread in distribution. Positivity was observed in carcinoma cells in all cases, typically weak and focal (range 2-4). Using a total score of 4 as a cutoff for definitively positive staining, desmin staining was positive in mesothelial cells in 25/25 cases and carcinoma cells in 1/22 cases (P < .0001, Fisher's exact test). Additionally, using the Mann-Whitney ranked sum test on the 20 cases with evaluable mesothelial cells, the medians of the total scores for mesothelial cells (5.5) and carcinoma cells (2.5) were significantly different (P < .0001). CONCLUSION: A total score of > or = 4 was significantly associated with mesothelial cell staining. Use of desmin immunohistochemical staining in cell block preparations may be helpful in distinguishing between mesothelial cells and carcinoma.

Adenocarcinoma↗