Retrospective study of prevalence of Community Associated Methicillin Resistant Staphylococcus Aureus (CA-MRSA) seen in Texas MedClinics, San Antonio, TX from April 2006-August 2009

Purpose. To evaluate the presence of Community Associated–Methicillin Resistant Staphylococcus Aureus, CA-MRSA, in abscesses and skin and soft tissue infections presenting at 9 urgent care clinics in San Antonio, TX. ^ Methods. During the 40-month retrospective study (April 2006 to August 2009), wound cultures collected in 9 urgent care centers were evaluated for MRSA growth, antibiotics prescribed, follow up wound care, and antibiotic prescribing habits by physicians for all patients presenting with abscesses and skin/soft tissue infections. ^ Results. Across 9 urgent care centers in San Antonio, TX, 36,797 abscesses and cases of skin and soft tissue infections were treated during 40 months. Of the 36,797 cases, 9290 patients had wound cultures sent with 5,630 cultures sent to Texas MedClinic’s primary lab. Of the 5630 cultures sent to their primary lab, this reflected a prevalence of 4727 (84 %) cultures were positive for MRSA. Of the 9290 patients who had a wound culture sent (April 10th, 2006 to August 31st, 2009), a total of 4,307 antibiotics were prescribed. The top five antibiotics prescribed for CA-MRSA were Bactrim (55.5%), Clindamycin (18.4%), Bactroban (5%), Amoxicillin (3.5%), and Doxycycline (3%) representing 85.4% of the antibiotics prescribed. 8809/9290 (94.8%) of patients required no more than 3 follow up visits. Of the 33 physicians working full time during the entire study period, 29/33 (87.8%) of the physicians were family medicine physicians and represented varied prescribing rates of antibiotics between 11-76% with 26/33 (78.8%) of physicians prescribing antibiotics greater than 40% of the time.^ Conclusions. Abscesses and soft tissue infections are a common presenting complaint to urgent care centers. This study reveals that antibiotic-prescribing practices can be improved with physician education since this high prevalence was not known previously. Also, treating abscesses with limited packing has been shown to be a viable option in this particular circumstance and would be open field for additional clinical research. Due to the high prevalence of CA-MRSA skin and soft tissue infections among patients presenting to urgent care centers presumptive treatment for MRSA is indicated. Increasing levels of resistance to penicillin antibiotics is concerning and warrants alternative antibiotic management strategies.^

Sr/Ca ratios of coccoliths from the Paleocene-Eocene Thermal Maximum

During the Paleocene-Eocene Thermal Maximum (PETM), rapid release of isotopically light C to the ocean-atmosphere system elevated the greenhouse effect and warmed temperatures by 5-7 °C for 105 yr. The response of the planktic ecosystems and productivity to the dramatic climate changes of the PETM may represent a significant feedback to the carbon cycle changes, but has been difficult to document. We examine Sr/Ca ratios in calcareous nannofossils in sediments spanning the PETM in three open ocean sites as a new approach to examine productivity and ecological shifts in calcifying plankton. The large heterogeneity in Sr/Ca among different nannofossil genera indicates that nannofossil Sr/Ca reflects primary productivity-driven geochemical signals and not diagenetic overprinting. Elevated Sr/Ca ratios in several genera and constant ratios in other genera suggest increased overall productivity in the Atlantic sector of the Southern Ocean during the PETM. Dominant nannofossil genera in tropical Atlantic and Pacific sites show Sr/Ca variations during the PETM which are comparable to background variability prior to the PETM. Despite acidification of the ocean there was not a productivity crisis among calcifying phytoplankton. We use the Pandora ocean box model to explore possible mechanisms for PETM productivity change. If independent proxy evidence for more stratified conditions in the Southern Ocean during the PETM is robust, then maintenance of stable or increased productivity there likely reflects increased nutrient inventories of the ocean. Increased nutrient inventories could have resulted from climatically enhanced weathering and would have important implications for burial rates of organic carbon and stabilization of climate and the carbon cycle.

Rb-Sr isotope systematics and Sr/Ca-Ba/Ca ratios at DSDP Hole 89-462A

Four samples of Nauru Basin basalts (Cores 94 to 109 of Hole 462A, sub-bottom depth 1077-1209 m) have 87Sr/86Sr ratios in the range 0.7037 to 0.7038, which is distinctly higher than the ratios of N-type MORB. The Rb contents of the samples are depleted in comparison with those of MORB and ocean-island basalts. These chemical and isotopic characteristics are identical to those of the basalts previously drilled during Leg 61 (Cores 75 to 90 of Hole 462A), and are explained in terms of inhomogeneity of the source region in the mantle or later alteration effects. Sr/Ca-Ba/Ca systematics of 15 samples from Cores 462A-94 to 462A-109 and 14 samples from Cores 462A-75 to 462A-90 suggest that the Nauru Basin basalts are derived from a mantle peridotite by 20 to 30% partial melting with subsequent Plagioclase crystallization.

Mg/Ca and stable oxygen measurement of the past 27 Ma of ODP Hole 120-747A

We explore the applicability of paired Mg/Ca and 18O/16O measurements on benthic foraminifera from Southern Ocean site 747 to paleoceanographic reconstructions on pre-Pleistocene timescales. We focus on the late Oligocene through Pleistocene (27-0 Ma) history of paleotemperatures and the evolution of the d18O values of seawater (d18Osw) at a temporal resolution of ~100-200 kyr. Absolute paleotemperature estimates depend on assumptions of how Mg/Ca ratios of seawater have changed over the past 27 Myr, but relative changes that occur on geologically brief timescales are robust. Results indicate that at the Oligocene to Miocene boundary (23.8 Ma), temperatures lag the increase in global ice-volume deduced from benthic foraminiferal d18O values, but the smaller-scale Miocene glaciations are accompanied by ocean cooling of -1°C. During the mid-Miocene phase of Antarctic ice sheet growth (~15-13 Ma), water temperatures cool by ~3°C. Unlike the benthic foraminiferal d18O values, which remain relatively constant thereafter, temperatures vary (by 3°C) and reach maxima at ~12 and ~8.5 Ma. The onset of significant Northern Hemisphere glaciation during the late Pliocene is synchronous with an ~4°C cooling at site 747. A comparison of our d18Osw curve to the Haq et al. (1987, doi:10.1126/science.235.4793.1156 ) sea level curve yields excellent agreement between sequence boundaries and times of increasing seawater 18O/16O ratios. At ~12-11 Ma in particular, when benthic foraminiferal d18O values do not support a further increase in ice volume, the d18Osw curve comes to a maximum that corresponds to a major mid-Miocene sea level regression. The agreement between the character of our Mg/Ca-based d18Osw curve and sequence stratigraphy demonstrates that benthic foramaniferal Mg/Ca ratios can be used to trace the d18Osw on pre-Pleistocene timescales despite a number of uncertainties related to poorly constrained temperature calibrations and paleoseawater Mg/Ca ratios. The Mg/Ca record also highlights that deep ocean temperatures can vary independently and unexpectedly from ice volume changes, which can lead to misinterpretations of the d18O record.