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Biomedical subjects

Sarah Y Park

Publications and source records attributed to Sarah Y Park.

8 recordsLinked to original sources

Nursing home outbreak of invasive group a streptococcal infections caused by 2 distinct strains.

OBJECTIVE: To identify factors contributing to a cluster of deaths from invasive group A streptococcus (GAS) infection in a nursing home facility and to prevent additional cases. DESIGN: Outbreak investigation. SETTING: A 146-bed nursing home facility in northern Nevada. METHODS: We defined a case as the isolation of GAS from a normally sterile site in a resident of nursing home A. To identify case patients, we reviewed resident records from nursing home A, the local hospital, and the hospital laboratory. We obtained oropharyngeal and skin lesion swabs from staff and residents to assess GAS colonization and performed emm typing on available isolates. To identify potential risk factors for transmission, we performed a cohort study and investigated concurrent illness among residents and surveyed staff regarding infection control practices. RESULTS: Six residents met the case patient definition; 3 (50%) of them died. Among invasive GAS isolates available for analysis, 2 distinct strains were identified: emm11 (3 isolates) and emm89 (2 isolates). The rate of GAS carriage was 6% among residents and 4% among staff; carriage isolates were emm89 (8 isolates), emm11 (2 isolates), and emm1 (1 isolate). Concurrently, 35 (24%) of the residents developed a respiratory illness of unknown etiology; 41% of these persons died. Twenty-one (30%) of the surveyed employees did not always wash their hands before patient contacts, and 27 (38%) did not always wash their hands between patient contacts. CONCLUSIONS: Concurrent respiratory illness likely contributed to an outbreak of invasive GAS infection from 2 strains in a highly susceptible population. This outbreak highlights the importance of appropriate infection control measures, including respiratory hygiene practices, in nursing home facilities.

Aged↗

Emergence of community-associated methicillin resistant Staphylococcus aureus in Hawaii, 2001-2003.

OBJECTIVES: We conducted a retrospective study to determine trends and characteristics of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Hawaii. METHODS: We reviewed medical records of patients with MRSA infections during July 2001-June 2003 in four healthcare facilities. A case was defined as a patient with MRSA infection (colonization excluded), diagnosed in ambulatory settings or < or = 48 h after hospitalization, without previous MRSA or healthcare risk factors. Pulsed-field gel electrophoresis (PFGE) and typing of resistance and toxin genes was performed in 40 MRSA isolates. RESULTS: CA-MRSA infections increased from 28 (23% of MRSA infections) to 65 (32%) per quarter over the 2-year period (P<0.05). Pacific islanders accounted for 51% of 389 case-patients, but only 24% of the Hawaii population. In the pediatric hospital, Pacific Islanders represented 76% of 90 case-patients versus 35% of the hospital population. Hospital admission, required for 40% (154/389), was associated with prior antimicrobial treatment (P<0.01). The staphylococcal cassette chromosome mec type IV was detected in 38/40 isolates; 31 isolates carried Panton-Valentine leukocidin genes and 22 belonged to the same staphylococcal lineage. CONCLUSIONS: In Hawaii, prevention strategies for CA-MRSA infections should focus on Pacific Islanders. CA-MRSA infections in Hawaii appear to be related to strains causing disease throughout the United States.

Adolescent↗

Epidemiologic study and containment of a nosocomial outbreak of severe acute respiratory syndrome in a medical center in Kaohsiung, Taiwan.

OBJECTIVE: We conducted an epidemiologic investigation at the beginning of a nosocomial outbreak of severe acute respiratory syndrome (SARS) to clarify the dynamics of SARS transmission, the magnitude of the SARS outbreak, and the impact of the outbreak on the community. METHODS: We identified all potential cases of nosocomially acquired SARS, linked them to the most likely infection source, and described the hospital containment measures. SETTING: A 2,300-bed medical center in Kaohsiung, Taiwan. RESULTS: A total of 55 cases of SARS were identified, and 227 hospital workers were quarantined. The index patient and neighboring patients were isolated. A chest physician team reviewed medical charts and chest radiographs and monitored the development of SARS in patients staying in the ward. The presence of underlying lung disease and immunocompromise in some patients made the diagnosis of SARS difficult. Some cases of SARS were diagnosed after the patients had died. Medical personnel were infected only if they cared for patients with unrecognized SARS, and caretakers played important roles in transmission of SARS to family members. As the number of cases of nosocomial SARS increased, the hospital closed the affected ward and expedited construction of negative-pressure rooms on other vacated floors for patient cohorting, and the last case in the hospital was identified 1 week later. CONCLUSIONS: Timely recognition of SARS is extremely important. However, given the limitations of SARS testing, possible loss of epidemic links, and the nonspecific clinical presentations in hospitalized patients, it is very important to establish cohorts of persons with low, medium, and high likelihoods of SARS acquisition. Rapid closure of affected wards may minimize the impact on hospital operations. Establishment of hospitals dedicated to appropriate treatment of patients with SARS might minimize the impact of the disease in future epidemics.

Aged↗

Clinicians' management of children and adolescents with acute pharyngitis.

OBJECTIVE: Sore throat is a common complaint in children and adolescents. With increasing antimicrobial resistance because of antimicrobial overuse, accurate diagnosis is imperative. Appropriate management of acute pharyngitis depends on proper use and interpretation of clinical findings, rapid antigen-detection tests, and throat cultures. We surveyed pediatricians and family physicians to evaluate their management strategies for children and adolescents with acute pharyngitis and to assess the availability and use of diagnostic tests in office practice. METHODS: In 2004, surveys were mailed to a random sample of 1000 pediatrician members of the American Academy of Pediatrics and 1000 family physician members of the American Academy of Family Physicians. We assessed factors associated with physicians using an appropriate management strategy for treating acute pharyngitis. RESULTS: Of 948 eligible responses, 42% of physicians would start antimicrobials before knowing diagnostic test results and continue them despite negative results, with 27% doing this often or always. When presented with clinical scenarios of patients with acute pharyngitis, < or =23% chose an empirical approach, 32% used an inappropriate strategy for a child with pharyngitis suggestive of group A Streptococcus, and 81% used an inappropriate strategy for a child with findings consistent with viral pharyngitis. Plating cultures in the office was associated with an appropriate management strategy, although not statistically significant. Solo/2-person practice and rural location were both independent factors predicting inappropriate strategies. CONCLUSIONS: There is much room for improvement in the management of acute pharyngitis in children and adolescents. Most physicians use appropriate management strategies; however, a substantial number uses inappropriate ones, particularly for children with likely viral pharyngitis. Efforts to help physicians improve practices will need to be multifaceted and should include health policy and educational approaches.

Acute Disease↗

Methicillin-resistant Staphylococcus aureus, Hawaii, 2000-2002.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has generated considerable concern among medical and public health professionals. We used a statewide, population-based antimicrobial resistance surveillance system to examine epidemiologic trends for MRSA from outpatients and inpatients in Hawaii. Pediatric and adult patient populations were compared to assess characteristics of MRSA isolates specific for each group. From 2000 to 2002, 8,206 (26%) of 31,482 total S. aureus isolates were MRSA. During this period, the proportion of MRSA isolates increased in both outpatient and inpatient clinical settings (p<0.01). When stratified by age, annual trends showed a significant increase in the proportion of MRSA in adult patients (from 24% to 30%, p<0.01) but not in pediatric patients (from 25% to 27%, p>0.05). Although MRSA isolates from adults demonstrated high resistance to most non-beta-lactams, most MRSA isolates from pediatric outpatients remained susceptible to most non-beta-lactams.

Adolescent↗

Isolate removal methods and methicillin-resistant Staphylococcus aureus surveillance.

The effect of duplicate isolate removal strategies on Staphylococcal aureus susceptibility to oxacillin was compared by using antimicrobial test results for 14,595 isolates from statewide surveillance in Hawaii in 2002. No removal was compared to most resistant and most susceptible methods at 365 days and to the National Committee for Clinical Laboratory Standards (NCCLS) and Cerner algorithms at 3-, 10-, 30-, 90-, and 365-day analysis periods. Overall, no removal produced the lowest estimates of susceptibility. Estimates with either NCCLS or Cerner differed by <2% when the analysis period was the same; with either method, the difference observed between a 90- and a 365-day period was <1%. The effect of duplicate isolate removal was greater for inpatient than outpatient settings. Considering the ease of implementation and comparability of results, we recommend using the first isolate of a given species per patient to calculate susceptibility frequencies for S. aureus to oxacillin.

Anti-Bacterial Agents↗

Vancomycin-resistant Staphylococcus aureus in the absence of vancomycin exposure.

We report findings from our investigation of the world's second clinical isolate of vancomycin-resistant Staphylococcus aureus (VRSA). An elderly man was hospitalized with an infected chronic heel ulcer and osteomyelitis. Before hospital admission, he received multiple courses of antibiotic therapy but, notably, no vancomycin. Numerous cultures of ulcer specimens (performed on an outpatient basis) grew methicillin-resistant, vancomycin-susceptible S. aureus and vancomycin-resistant Enterococcus species. At admission, an additional culture of a specimen from the heel ulcer grew S. aureus that was identified as VRSA (minimal inhibitory concentration for vancomycin [by broth-microdilution], 32 microg/mL). Further evaluation confirmed the presence of the vanA gene mediating vancomycin resistance. To assess VRSA transmission, we performed a carriage study of 283 identified contacts and an environmental survey of the patient's home; no VRSA isolates were recovered. This case illustrates that recent exposure by patients to vancomycin is not necessary for development of vanA-containing VRSA. For clinical and public health reasons, it is essential that microbiology laboratories adequately test for vancomycin-resistance in S. aureus.

Aged↗