The Challenge to Interpret Antimicrobial Susceptibility at a Small Community Hospital

Abstract Objective: We aimed to determine the prevailing resistance rates at a local community hospital for a select group of gram-positive and gram-negative microorganisms for the period 2008-2012. Methods: Aerobic and facultative anaerobic culture isolates representing blood, urine and wounds specimens from all wards were tested at the Microbiology Laboratory, using the MicroScan AutoScan4, to determine antimicrobial susceptibility at the local community hospital. Results: the findings allude to the prevalence of resistance at the institution for the period under review. Conclusion: Resistance trends are speculative at best without the inclusion of molecular characterization of resistance and consumption data. Pharmacists should play a greater role in the determination of resistance by providing the microbiologist with consumption or utilization data, such as the daily defined dose. The inclusion of the daily defined dose in the estimation of resistance would allow clinicians to determine if selective pressure may have contributed to the prevailing resistance rates

Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report

<p>Abstract</p> <p>Introduction</p> <p>Certain <it>Staphylococcus aureus </it>strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive <it>Staphylococcus aureus </it>strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country.</p> <p>Case presentation</p> <p>A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by <it>S. aureus</it>. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and <it>spa </it>typing, and the results revealed that the <it>S. aureus </it>isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles.</p> <p>Conclusion</p> <p>Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive <it>S. aureus </it>isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.</p

Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report

<p>Abstract</p> <p>Introduction</p> <p>Certain <it>Staphylococcus aureus </it>strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive <it>Staphylococcus aureus </it>strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country.</p> <p>Case presentation</p> <p>A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by <it>S. aureus</it>. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and <it>spa </it>typing, and the results revealed that the <it>S. aureus </it>isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles.</p> <p>Conclusion</p> <p>Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive <it>S. aureus </it>isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.</p

Decadal-scale litter manipulation alters the biochemical and physical character of tropical forest soil carbon

© 2018 Elsevier Ltd Climate change and rising atmospheric carbon dioxide (CO2) concentrations are likely to alter tropical forest net primary productivity (NPP), potentially affecting soil C storage. We examined biochemical and physical changes in soil C fractions in a humid tropical forest where experimental litter manipulation changed total soil C stocks. We hypothesized that: (1.) low-density soil organic C (SOC) fractions are more responsive to altered litter inputs than mineral-associated SOC, because they cycle relatively rapidly. (2.) Any accumulation of mineral-associated SOC with litter addition is relatively stable (i.e. low leaching potential). (3.) Certain biomolecules, such as waxes (alkyl) and proteins (N-alkyl), form more stable mineral-associations than other biomolecules in strongly weathered soils. A decade of litter addition and removal affected bulk soil C content in the upper 5 cm by +32% and −31%, respectively. Most notably, C concentration in the mineral-associated SOC fraction was greater in litter addition plots relative to controls by 18% and 28% in the dry and wet seasons, respectively, accounting for the majority of greater bulk soil C stock. Radiocarbon and leaching analyses demonstrated that the greater mineral-associated SOC in litter addition plots consisted of new and relatively stable C, with only 3% of mineral-associated SOC leachable in salt solution. Solid-state13C NMR spectroscopy indicated that waxes (alkyl C) and microbial biomass compounds (O-alkyl and N-alkyl C) in mineral-associated SOC are relatively stable, whereas plant-derived compounds (aromatic and phenolic C) are lost from mineral associations on decadal timescales. We conclude that changes in tropical forest NPP will alter the quantity, biochemistry, and stability of C stored in strongly weathered tropical soils