Prevalence and Antimicrobial Agent Susceptibility of Methicillin-resistant Staphylococcus aureus in Healthy Pediatric Outpatients in Las Vegas

Colonization and infection by community-associated resistant strains of Staphylococcus aureus are being reported in epidemic proportions. The purpose of this study was to determine the local prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization in children and to characterize the MRSA isolates in the laboratory with regard to antimicrobial agent susceptibility patterns, and the presence of the mecA and the Panton-Valentine leukocidin (PVL) genes. Nasal swabs were collected at two pediatric clinics from a total of 505 children during health maintenance visits. A brief questionnaire was administered to collect demographic data and pertinent medical, family, and social history. Samples were cultured onto 2 selective media for S. aureus and MRSA. Potential MRSA isolates were further evaluated by real-time polymerase chain reaction (PCR), and for susceptibility to eight antibiotics by disk diffusion. Culture results showed that MRSA was present in 15 of the 505 specimens (3.0%). Six different antimicrobial susceptibility profiles were observed among the MRSA isolates. PCR amplification results showed that all 15 MRSA isolates were positive for the presence of the mecA gene, and 10 MRSA isolates contained the PVL gene. Understanding local prevalence rates and the role of colonization in infection are needed to develop effective interventions to reduce MRSA infections

THE DEGRADATION AND UTILIZATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY INDIGENOUS SOIL BACTERIA (NAPHTHALENE, FLUORENE, ANTHRACENE, PYRENE).

The persistance of industrially derived polycyclic aromatic hydrocarbons in the subsurface may be significantly affected by the metabolism of soil bacteria. This study was conducted to determine the ability of indigenous soil bacteria to decrease the concentration of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, anthracene, and pyrene) and to utilize the compounds as a substrate for growth. Soil cores from petroleum contaminated and non-contaminated sites contained 10⁵ - 10⁷ viable microorganisms per gram dry weight of soil. Gram negative rod-shaped bacteria predominated. Decreases in the concentration of the four polycyclic aromatic hydrocarbons were observed during incubation with bacterial isolates in aqueous suspension by the use of high performance liquid chromatography. Corresponding increases in bacterial numbers indicated utilization of the compounds as a carbon source. Soil samples from the contaminated sites contained greater numbers of bacteria utilizing anthracene and pyrene than soil samples from non-contaminated sites. Degradation rates of the four polycyclic aromatic hydrocarbons were related to the compound, its concentration, and the bacterium. Biodegradation of pyrene was positively correlated with the presence of oxygen. Pyrene was biodegraded by an Acinetobacter sp. under aerobic conditions but not under anaerobic or microaerophilic conditions. Studies with radiolabeled ¹⁴C-anthracene demonstrated utilization of the labeled carbon as a source of carbon by viable bacterial cells in aqueous suspension. Incorporation of ¹⁴C into cellular biomass however was not observed during incubation of ¹⁴C-anthracene in soil

Identification of subsurface microorganisms at Yucca Mountain; Fourth quarterly report

Bacteria isolated from water samples collected in a series of ground water springs have been isolated, enumerated, and identified from twenty six sites. Ten sites were sampled in Death Valley, California and sixteen sites were sampled in Ash Meadows, Nevada. Replicate samples were collected and tested from four locations. All water samples were collected in conjunction with the HRC chemistry group conducting ground water fingerprinting studies. The protocol for collection of samples, as described in the 3rd quarterly report, specified aseptic collection in sterile screw-capped containers and transportation on ice to the HRC microbiology laboratory. All samples were inoculated by spread plating onto R2A (Difco Laboratories, Detroit, MI) bacterial culture medium. the R2A plates were then incubated at 28{degrees} for 5--7 days and colonies wee counted with the aid of a grid template and magnifying lens

Isolation, identification, and characterization of ground water bacteria

Ground water is an increasingly significant source of potable water and is one of the least studied ecosystems on earth. Assessment of man's impact on this resource requires knowledge of the microbial populations present. Over 500 bacteria were isolated from well water samples on a low nutrient medium (R2A). Gram-negative, rod shaped, nonmotile bacteria predominated. Acinetobacter spp. comprised 54% of the total isolates. Direct counts using ep i f 1 uorescent microscopy revealed that representative isolates grew significantly in filtered well water. Growth of Acinetobacter sp. was significantly enhanced in water enriched with low concentrations (100 ug carbon/liter or 1000 ug carbon/liter) of glucose, acetate, succinate, or pyruvate. The growth and survival of an Acinetobacter sp., an opportunistic pathogen, in water had not previously been described. Bacterial survival studies conducted on water samples from 19 wells throughout the Tucson basin revealed the presence of a significant population of bacteria capable of rapid growth and survival in unamended native well water.hydrology collectio

Statistical Analysis and Interpretation of Building Characterization, Indoor Environmental Quality Monitoring and Energy Usage Data from Office Buildings and Classrooms in the United States

Three independent tasks had been performed (Stetzenbach 2008, Stetzenbach 2008b, Stetzenbach 2009) to measure a variety of parameters in normative buildings across the United States. For each of these tasks 10 buildings were selected as normative indoor environments. Task 1 focused on office buildings, Task 13 focused on public schools, and Task 0606 focused on high performance buildings. To perform this task it was necessary to restructure the database for the Indoor Environmental Quality (IEQ) data and the Sound measurement as several issues were identified and resolved prior to and during the transfer of these data sets into SPSS. During overview discussions with the statistician utilized in this task it was determined that because the selection of indoor zones (1-6) was independently selected within each task; zones were not related by location across tasks. Therefore, no comparison would be valid across zones for the 30 buildings so the by location (zone) data were limited to three analysis sets of the buildings within each task. In addition, differences in collection procedures for lighting were used in Task 0606 as compared to Tasks 01 & 13 to improve sample collection. Therefore, these data sets could not be merged and compared so effects by-day data were run separately for Task 0606 and only Task 01 & 13 data were merged. Results of the statistical analysis of the IEQ parameters show statistically significant differences were found among days and zones for all tasks, although no differences were found by-day for Draft Rate data from Task 0606 (p>0.05). Thursday measurements of IEQ parameters were significantly different from Tuesday, and most Wednesday measures for all variables of Tasks 1 & 13. Data for all three days appeared to vary for Operative Temperature, whereas only Tuesday and Thursday differed for Draft Rate 1m. Although no Draft Rate measures within Task 0606 were found to significantly differ by-day, Temperature measurements for Tuesday and Thursday showed variation. Moreover, Wednesday measurements of Relative Humidity within Task 0606 varied significantly from either Tuesday or Thursday. The majority of differences in IEQ measurements by-zone were highly significant (p<0.001), with the exception of Relative Humidity in some buildings. When all task data were combined (30 buildings) neither the airborne culturable fungi nor the airborne non-culturable spore data differed in the concentrations found at any indoor location in terms of day of collection. However, the concentrations of surface-associated fungi varied among the day of collection. Specifically, there was a lower concentration of mold on Tuesday than on Wednesday, for all tasks combined. As expected, variation was found in the concentrations of both airborne culturable fungi and airborne non-culturable fungal spores between indoor zones (1-6) and the outdoor zone (zone 0). No variation was found among the indoor zones of office buildings for Task 1 in the concentrations of airborne culturable fungi. However, airborne non-culturable spores did vary among zones in one building in Task 1 and variation was noted between zones in surface-associated fungi. Due to the lack of multiple lighting measurements for Tasks 13 and 0606, by-day comparisons were only performed for Task 1. No statistical differences were observed in lighting with respect to the day of collection. There was a wide range of variability by-zone among seven of the office buildings. Although few differences were found for the brightest illumination of the worksurface (IllumWkSfcBrtst) and the darkest illumination of the worksurface (IllumWkSfcDrkst) in Task 1, there was considerable variation for these variables in Task 13 and Task 0606 (p < 0.001). Other variables that differed by-zone in Task 13 include CombCCT and AmbCCT1 for S03, S07, and S08. Additionally, AmbChromX1, CombChromY, and CombChromX varied by-zone for school buildings S02, S04, and S05, respectively. Although all tasks demonstrated significant differences in sound measurements by zone, some of the buildings within each task did not appear to differ in sound quality. Hence, post-hoc tests were not appropriate and individual zones were not compared for these buildings. It is interesting to note that sound measurements in some buildings were widely varied with most zone comparisons and other buildings varied between only a few zones

Environmental Microbiology : the dictionary

iii, 178 p. : ill.; 22 cm

Evaluation of Four Aerobiological Sampling Methods for the Retrieval of Aerosolized Pseudomonas syringae

The Andersen six-stage impactor, the SAS (Surface Air System) impactor, the AGI-30 impinger, and gravity plates were evaluated for the retrieval of aerosol-released Pseudomonas syringae. The upper limits of the impactor samplers were exceeded at a spray concentration of 10(7) CFU/ml, indicating that these samplers are not appropriate for monitoring high airborne concentrations. Decreased cell concentrations were retrieved with increased sampling time for the Andersen and AGI samplers, indicating that a minimum sampling time is preferable for monitoring aerosolized vegetative cells

Statistical Analysis and Interpretation of Building Characterization, Indoor Environmental Quality Monitoring and Energy Usage Data from Office Buildings and Classrooms in the United States

Three independent tasks had been performed (Stetzenbach 2008, Stetzenbach 2008b, Stetzenbach 2009) to measure a variety of parameters in normative buildings across the United States. For each of these tasks 10 buildings were selected as normative indoor environments. Task 1 focused on office buildings, Task 13 focused on public schools, and Task 0606 focused on high performance buildings. To perform this task it was necessary to restructure the database for the Indoor Environmental Quality (IEQ) data and the Sound measurement as several issues were identified and resolved prior to and during the transfer of these data sets into SPSS. During overview discussions with the statistician utilized in this task it was determined that because the selection of indoor zones (1-6) was independently selected within each task; zones were not related by location across tasks. Therefore, no comparison would be valid across zones for the 30 buildings so the by location (zone) data were limited to three analysis sets of the buildings within each task. In addition, differences in collection procedures for lighting were used in Task 0606 as compared to Tasks 01 & 13 to improve sample collection. Therefore, these data sets could not be merged and compared so effects by-day data were run separately for Task 0606 and only Task 01 & 13 data were merged. Results of the statistical analysis of the IEQ parameters show statistically significant differences were found among days and zones for all tasks, although no differences were found by-day for Draft Rate data from Task 0606 (p>0.05). Thursday measurements of IEQ parameters were significantly different from Tuesday, and most Wednesday measures for all variables of Tasks 1 & 13. Data for all three days appeared to vary for Operative Temperature, whereas only Tuesday and Thursday differed for Draft Rate 1m. Although no Draft Rate measures within Task 0606 were found to significantly differ by-day, Temperature measurements for Tuesday and Thursday showed variation. Moreover, Wednesday measurements of Relative Humidity within Task 0606 varied significantly from either Tuesday or Thursday. The majority of differences in IEQ measurements by-zone were highly significant (p<0.001), with the exception of Relative Humidity in some buildings. When all task data were combined (30 buildings) neither the airborne culturable fungi nor the airborne non-culturable spore data differed in the concentrations found at any indoor location in terms of day of collection. However, the concentrations of surface-associated fungi varied among the day of collection. Specifically, there was a lower concentration of mold on Tuesday than on Wednesday, for all tasks combined. As expected, variation was found in the concentrations of both airborne culturable fungi and airborne non-culturable fungal spores between indoor zones (1-6) and the outdoor zone (zone 0). No variation was found among the indoor zones of office buildings for Task 1 in the concentrations of airborne culturable fungi. However, airborne non-culturable spores did vary among zones in one building in Task 1 and variation was noted between zones in surface-associated fungi. Due to the lack of multiple lighting measurements for Tasks 13 and 0606, by-day comparisons were only performed for Task 1. No statistical differences were observed in lighting with respect to the day of collection. There was a wide range of variability by-zone among seven of the office buildings. Although few differences were found for the brightest illumination of the worksurface (IllumWkSfcBrtst) and the darkest illumination of the worksurface (IllumWkSfcDrkst) in Task 1, there was considerable variation for these variables in Task 13 and Task 0606 (p < 0.001). Other variables that differed by-zone in Task 13 include CombCCT and AmbCCT1 for S03, S07, and S08. Additionally, AmbChromX1, CombChromY, and CombChromX varied by-zone for school buildings S02, S04, and S05, respectively. Although all tasks demonstrated significant differences in sound measurements by zone, some of the buildings within each task did not appear to differ in sound quality. Hence, post-hoc tests were not appropriate and individual zones were not compared for these buildings. It is interesting to note that sound measurements in some buildings were widely varied with most zone comparisons and other buildings varied between only a few zones