Publications by authors named "Sigrid McAllister"
The Bruker Biotyper MALDI-TOF MS (Biotyper) system, with a modified 30 minute formic acid extraction method, was evaluated by its ability to identify 216 clinical Staphylococcus isolates from the CDC reference collection comprising 23 species previously identified by conventional biochemical tests. 16S rDNA sequence analysis was used to resolve discrepancies. Of these, 209 (96.
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- The study focused on the prevalence of vancomycin-resistant Staphylococcus aureus (VRSA) in adults with chronic lower-extremity wounds in southeastern Michigan, where most US cases have been identified.
- Of the 179 participants, 26% had methicillin-susceptible S. aureus, 27% had methicillin-resistant S. aureus, and only 4% carried vancomycin-resistant enterococcus (VRE). Only 3% had pSK41-positive S. aureus, indicating rare colonization with VRSA precursors.
- Persistent chronic wounds for over 2 years significantly increased the risk of colonization with pSK41-positive S
Data on the interaction between methicillin-resistant Staphylococcus aureus (MRSA) colonization and clinical infection are limited. During 2007-2008, we enrolled HIV-infected adults in Atlanta, Georgia, USA, in a prospective cohort study. Nares and groin swab specimens were cultured for S.
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- - Recent infection outbreaks in outpatient care, including a 2009 case where three patients developed severe MSSA infections after epidural injections, highlighted unsafe infection control practices as key risk factors.
- - A study of 110 patients revealed that 8 (7%) had infections, predominantly among those who received epidural injections, with poor adherence to infection control protocols observed during procedures, such as inadequate use of face masks and reusing syringes.
- - Genetic testing showed that MSSA strains from patients matched those of clinic staff, indicating that infection control failures likely contributed to the spread of the bacteria, underscoring the importance of strict infection control measures in outpatient settings.
The utility of Etest for antimicrobial susceptibility testing of Yersinia pestis was evaluated in comparison with broth microdilution and disk diffusion for eight agents. Four laboratories tested 26 diverse strains and found Etest to be reliable for testing antimicrobial agents used to treat Y. pestis, except for chloramphenicol and trimethoprim-sulfamethoxazole.
View Article and Find Full Text PDFWe compared the results obtained with six commercial MIC test systems (Etest, MicroScan, Phoenix, Sensititre, Vitek Legacy, and Vitek 2 systems) and three reference methods (agar dilution, disk diffusion, and vancomycin [VA] agar screen [VScr]) with the results obtained by the Clinical and Laboratory Standards Institute broth microdilution (BMD) reference method for the detection of VA-intermediate Staphylococcus aureus (VISA). A total of 129 S. aureus isolates (VA MICs by previous BMD tests,
This report describes the results of an 11-laboratory study to determine if a cefoxitin broth microdilution MIC test could predict the presence of mecA in staphylococci. Using breakpoints of < or = 4 microg/ml for mecA-negative and > or = 6 or 8 microg/ml for mecA-positive isolates, sensitivity and specificity based on mecA or presumed mecA for Staphylococcus aureus at 18 h of incubation were 99.7 to 100% in three cation-adjusted Mueller-Hinton broths tested.
View Article and Find Full Text PDFThis study characterizes methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates recovered from nasal cultures of noninstitutionalized individuals in the United States obtained in 2001 to 2004 as part of the National Health and Nutrition Examination Survey. Every tenth MSSA isolate and all MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE), screened for multiple toxin genes, and tested for susceptibility to 14 antimicrobial agents.
View Article and Find Full Text PDFBackground: Staphylococcus aureus is a common cause of infection, particularly in persons colonized by this organism. Virulent strains of methicillin-resistant S. aureus (MRSA) have emerged in the general community.
View Article and Find Full Text PDFMethicillin-resistant Staphylococcus aureus (MRSA) infections and methamphetamine use are emerging public health problems. We conducted a case-control investigation to determine risk factors for MRSA skin and soft tissue infections (SSTIs) in residents of a largely rural southeastern community in the United States. Case-patients were persons >12 years old who had culturable SSTIs; controls had no SSTIs.
View Article and Find Full Text PDFPhenotypic methods take several days for identification and antimicrobial susceptibility testing of staphylococcal isolates after gram-positive cocci in clusters (GPCC) are observed in positive blood cultures. We developed and validated a StaphPlex system that amplifies and detects 18 gene targets simultaneously in 1 reaction for species-level identification of staphylococci, detection of genes encoding Panton-Valentine leukocidin (PVL), and antimicrobial resistance determinants of staphylococci. The StaphPlex system was compared to phenotypic methods for organism identification and antimicrobial resistance detection for positive blood culture specimens in which GPCC were observed.
View Article and Find Full Text PDFPhenotypic methods for detecting mecA-mediated resistance in Staphylococcus aureus include both oxacillin and cefoxitin susceptibility tests; many laboratories perform multiple tests. Conflicting oxacillin and cefoxitin susceptibility results are most likely to occur for isolates that either have reduced susceptibility to oxacillin by a non-mecA-mediated mechanism or are mecA positive but are very heteroresistant. To understand the performance of oxacillin and cefoxitin tests for such isolates, we tested 135 S.
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- * CA-MRSA infections increased significantly, with Pacific Islanders disproportionately affected, making up 51% of cases despite only being 24% of Hawaii's population.
- * The findings suggest that prevention efforts should target Pacific Islanders, as the strains of CA-MRSA in Hawaii are linked to those prevalent in other parts of the United States.
During the 2003-04 influenza season, 17 cases of Staphylococcus aureus community-acquired pneumonia (CAP) were reported from 9 states; 15 (88%) were associated with methicillin-resistant S. aureus (MRSA). The median age of patients was 21 years; 5 (29%) had underlying diseases, and 4 (24%) had risk factors for MRSA.
View Article and Find Full Text PDFBackground: Staphylococcus aureus is a common cause of disease, particularly in colonized persons. Although methicillin-resistant S. aureus (MRSA) infection has become increasingly reported, population-based S.
View Article and Find Full Text PDFBackground: Methicillin-resistant Staphylococcus aureus (MRSA) infection typically occurs in chronically ill patients requiring long-term antimicrobial therapy or hospitalization. However, community-associated MRSA (CA-MRSA) necrotizing soft tissue infections seem to be increasing in incidence. Our aim was to describe the incidence and microbiologic characteristics of CA-MRSA isolates collected at an army community hospital.
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- Methicillin-resistant Staphylococcus aureus (MRSA) is spreading beyond hospitals, prompting a study of an outbreak among St. Louis Rams football players.
- Researchers conducted a study of players and staff, finding that MRSA infections were linked to specific positions on the team and a higher body mass index, with infections occurring primarily at turf-abrasion sites.
- The MRSA strain identified was similar to those from other community outbreaks, indicating a common source of the infections and highlighting the clone's presence in various regions across the U.S.
Article Synopsis
- The study aimed to compare the effectiveness of routine glove use by healthcare workers to contact-isolation precautions for residents with antibiotic-resistant infections in a skilled-care unit.
- Over an 18-month period, researchers tracked the acquisition of four types of antimicrobial-resistant organisms among residents under both infection-control strategies.
- Results showed no significant difference in infection rates between the two strategies, but contact-isolation precautions were 40% more expensive, suggesting that routine glove use might be more beneficial for cost and resident social interaction in long-term care settings.
Background And Objective: In August 2001, a cluster of MRSA skin infections was detected in a correctional facility. An investigation was conducted to determine its cause and to prevent further MRSA infections.
Design: Case-control study.
Nasal carriage of methicillin-resistant Staphylococcus aureus in an American Indian population.
Infect Control Hosp Epidemiol
February 2004
Background And Objective: Although reports of methicillin-resistant Staphylococcus aureus (MRSA) infections without healthcare exposure are increasing, population-based data regarding nasal colonization are lacking. We assessed the prevalence of and risk factors for community-associated MRSA nasal carriage in patients of a rural outpatient clinic.
Design: A cross-sectional population survey was conducted through random sample and stratification by community of residence.
Vancomycin-resistant Staphylococcus aureus isolate from a patient in Pennsylvania.
Antimicrob Agents Chemother
January 2004
A vancomycin-resistant Staphylococcus aureus (VRSA) isolate was obtained from a patient in Pennsylvania in September 2002. Species identification was confirmed by standard biochemical tests and analysis of 16S ribosomal DNA, gyrA, and gyrB sequences; all of the results were consistent with the S. aureus identification.
View Article and Find Full Text PDFOxacillin-resistant Staphylococcus aureus (ORSA) is a virulent pathogen responsible for both health care-associated and community onset disease. We used SmaI-digested genomic DNA separated by pulsed-field gel electrophoresis (PFGE) to characterize 957 S. aureus isolates and establish a database of PFGE patterns.
View Article and Find Full Text PDFDuring an investigation conducted December 17-20, 2001, we collected environmental samples from a U.S. postal facility in Washington, D.
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