Jill C. Roberts

Molecular Epidemiology of the fsr Locus and of Gelatinase Production among Different Subsets of Enterococcus faecalis Isolates

ABSTRACT We examined 215 Enterococcus faecalis isolates and found that neither the two-component regulatory locus fsr (E. faecalis regulator) nor gelatinase production was more common in disease-associated isolates than in isolates colonizing healthy individuals (ca. 60 to 65%). The majority of gelatinase-negative isolates, including 14 endocarditis isolates (of 80 isolates tested), contained the previously described 23.9-kb deletion and lacked fsrA and fsrB. While these findings indicate that neither fsr nor gelatinase is required for E. faecalis to cause infection, this study did not address whether fsr or gelatinase affects the severity of disease, as it does in animal models.

Fatal necrotizing pneumonia due to a Panton-Valentine leukocidin positive community-associated methicillin-sensitive Staphylococcus aureus and Influenza co-infection: a case report

Recent studies have described a number of fatalities due to methicillin-resistant Staphylococcus aureus (MRSA) and influenza virus co-infection. MRSA isolates provide a challenge to caregivers due to inherent wide range antibiotic resistance. Many facilities have instituted screening methods, based on the presence of antibiotic resistance genes, to identify MRSA positive patients upon admission. However, the resistance profile of the pathogen does not necessarily determine the severity of disease caused by that organism.We describe a fatal case of necrotizing pneumonia in a patient co-infected with Influenza B and a community-associated, PVL-positive methicillin-susceptible Staphylococcus aureus (MSSA).

Community-Associated Methicillin-Resistant Staphylococcus aureus Epidemic Clone USA300 in Isolates from Florida and Washington

ABSTRACT We examined 299 methicillin-resistant, community-associated Staphylococcus aureus isolates from Florida and Washington State for the presence of the USA300 epidemic clone. Pulsed-field gel electrophoresis demonstrated the epidemic clone in 43% of our S. aureus strains and in isolates from both states. The majority of the USA300 isolates (88%) were from wound infections.

An accelerated method for isolation of Salmonella enterica serotype Typhimurium from artificially contaminated foods, using a short preenrichment, immunomagnetic separation, and xylose-lysine-desoxycholate agar (6IX method).

Rapid isolation of Salmonella from food is essential for faster typing and source tracking in an outbreak. The objective of this study was to investigate a rapid isolation method that would augment the standard U.S. Food and Drug Administrations Bacteriological Analytical Manual (BAM) method. Food samples with low microbial load, including egg salad and ice cream, moderately high-microbial-load tomatoes, and high-microbial-load ground beef were intentionally inoculated with 2 to 48 CFU of Salmonella enterica serotype Typhimurium. The samples were preenriched in buffered peptone water for 6 h, and then selectively concentrated by immunomagnetic separation and plated for isolation on xylose-lysine-desoxycholate agar: the 6IX method. Salmonella Typhimurium was presumptively identified from approximately 97% of the low-microbial-load and moderately high-microbial-load samples by the 6IX method 2 days before the BAM standard method for isolation of Salmonella. In 49% of the beef samples, Salmonella Typhimurium was presumptively identified 1 or 2 days earlier by the 6IX method. Given the inocula used, our data clearly indicated that for most of the food samples tested, with the exception of ground beef, Salmonella Typhimurium could be isolated two laboratory days earlier with the 6IX method compared with the BAM method. In conclusion, this 6IX method may expedite Salmonella isolation and, therefore, has the potential to accelerate strain tracking for epidemiological analysis in a foodborne outbreak.

Community-associated methicillin-resistant staphylococcus aureus epidemic clone USA100; more than a nosocomial pathogen.

BackgroundWe characterized 100 USA100 epidemic MRSA from individuals in the community with no known healthcare-associated risk factors.FindingsMolecular epidemiology demonstrated 21 pulsed-field types and six spa types. SCCmec typing demonstrated that all of the strains possess the type II cassette. The staphylococcal enterotoxin D virulence gene was also present.ConclusionCharacterization of USA100 MRSA in the community illustrated the importance of nasal carriage, and the genetic diversity of the USA100 clone.

Two-Year Study Evaluating the Potential Loss of Methicillin Resistance in a Methicillin-Resistant Staphylococcus aureus Culture Collection

ABSTRACT A reported loss of mecA prompted us to monitor 360 cryostocked methicillin-resistant Staphylococcus aureus strains for stability. Concurrently, 14 well-characterized strains were stored in a Microbank preservation system and subjected to multiple freeze-thaw events. There were no significant declines in the methicillin-resistant populations with either method over a two-year period.

An Evidence-Based Project Demonstrating Increased School Immunization Compliance Following a School Nurse–Initiated Vaccine Compliance Strategy

During the 2012–2013 school year, only 66% of students at a Northern Indiana High School were in compliance with school immunization requirements. We report here successful implementation of evidence-based, time, and cost-effective methods aimed at increasing school immunization compliance. A three-stage strategy initiated by the school nurse was employed. In the first stage, letters were sent home with students, indicating the lack of compliance with school immunization laws. The next stage involved a second letter sent home with the student which contained immunization information from the Indiana State Department of Health, appointment information, and a copy of the student’s immunization record. In the final stage, letters were sent home via e-mail and phone calls were used for follow-up. At each stage, students and parents were given an explanation of exclusion and a date when exclusion would apply. Postintervention, vaccine compliance was 99.6%, exceeding both national and state averages.

Classification of Epidemic Community-Acquired Methicillin-Resistant Staphylococcus aureus by Anatomical Site of Isolation

Methicillin-resistant Staphylococcus aureus contributes significantly to cost, morbidity, and mortality due to infectious disease. We surveyed community-associated MRSA isolates to determine which strains were present within anatomical sites of interest. The most likely sources of MRSA among anatomic sites swabbed were wounds followed by the nasal cavity. The USA 300 MRSA strain was most commonly isolated among wound infections while nasal swabs largely yielded USA 100 MRSA. The frequency of isolation of USA 100 amongst community-associated strains is clinically significant as this strain is often correlated with invasive disease, exhibits broad antibiotic resistance, and has been considered to be hospital associated. The potential of USA 100 to cause serious disease and the frequency of its isolation suggest an important reservoir for opportunistic infection. These data demonstrate that MRSA epidemic clones are widespread among the community.

Draft Genome Sequence of Strain CBD-635, a Methicillin-Resistant Staphylococcus aureus USA100 Isolate.

ABSTRACT We present the draft genome sequence of methicillin-resistant Staphylococcus aureus strain CBD-635, from the USA100 lineage. This is a sepsis isolate obtained from Tampa General Hospital. This strain is spa type t003 and multilocus sequence typing (MLST) type ST5, and it has been used by our group in the study of novel antimicrobial chemotherapeutics.

Bacterial growth in media mimicking the high salt and alkalinity of extreme kazakhstan environments results in production of antimicrobial compounds in soil actinomycetes isolated from these extremophile locations

Increasing antibiotic resistance among multidrug resistant pathogens necessitates the search for newer antimicrobials. Streptomyces historically produce the largest number of antibacterials and herein we describe isolation of antagonists from extremophiles using unusual culture media. Antagonists or antimicrobials produced under extremophile environmental conditions demonstrated activity against MRSA from Kazakhstan and the United States.