Genetic relatedness and molecular characterization of multidrug resistant Acinetobacter baumannii isolated in central Ohio, USA

<p>Abstract</p> <p>Background</p> <p>Over the last decade, nosocomial infections due to <it>Acinetobacter baumannii </it>have been described with an increasing trend towards multidrug resistance, mostly in intensive care units. The aim of the present study was to determine the clonal relatedness of clinical isolates and to elucidate the genetic basis of imipenem resistance.</p> <p>Methods</p> <p><it>A. baumannii </it>isolates (n = 83) originated from two hospital settings in central Ohio were used in this study. Pulsed-field gel electrophoresis genotyping and antimicrobial susceptibility testing for clinically relevant antimicrobials were performed. Resistance determinants were characterized by using different phenotypic (accumulation assay for efflux) and genotypic (PCR, DNA sequencing, plasmid analysis and electroporation) approaches.</p> <p>Results</p> <p>The isolates were predominantly multidrug resistant (>79.5%) and comprised of thirteen unique pulsotypes, with genotype VII circulating in both hospitals. The presence of <it>bla</it>_OXA-23in 13% (11/83) and IS_{<it>Aba1 </it>}linked <it>bla</it>_OXA-66in 79.5% (66/83) of clinical isolates was associated with high level imipenem resistance. In this set of OXA producing isolates, multidrug resistance was bestowed by <it>bla</it>_ADC-25, class 1 integron-borne aminoglycoside modifying enzymes, presence of sense mutations in <it>gyrA</it>/<it>parC </it>and involvement of active efflux (with evidence for the presence of <it>adeB </it>efflux gene).</p> <p>Conclusion</p> <p>This study underscores the major role of carbapenem-hydrolyzing class D β-lactamases, and in particular the acquired OXA-23, in the dissemination of imipenem-resistant <it>A. baumannii</it>. The co-occurrence of additional resistance determinant could also be a significant threat.</p

Molecular characterization of hand flora and environmental isolates in a community setting

http://deepblue.lib.umich.edu/bitstream/2027.42/55436/1/Pancholi P, Molecular characterization of hand flora and environmental isolates in a community setting, 2005.pd

Comparison of the next-generation Xpert MRSA/SA BC assay and the GeneOhm StaphSR assay to routine culture for identification of Staphylococcus aureus and methicillin-resistant S. aureus in positive-blood-culture broths

A bloodstream infection with Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), is a serious condition that carries a high mortality rate and is also associated with significant hospital costs. The rapid and accurate identification and differentiation of methicillin-susceptible S. aureus (MSSA) and MRSA directly from positive blood cultures has demonstrated benefits in both patient outcome and cost-of-care metrics. We compare the next-generation Xpert MRSA/SA BC (Xpert) assay to the GeneOhm StaphSR (GeneOhm) assay for the identification and detection of S. aureus and methicillin resistance in prospectively collected blood culture broths containing Gram-positive cocci. All results were compared to routine bacterial culture as the gold standard. Across 8 collection and test sites, the Xpert assay demonstrated a sensitivity of 99.6% (range, 96.4% to 100%) and a specificity of 99.5% (range, 98.0% to 100%) for identifying S. aureus, as well as a sensitivity of 98.1% (range, 87.5% to 100%) and a specificity of 99.6% (range, 98.3% to 100%) for identifying MRSA. In comparison, the GeneOhm assay demonstrated a sensitivity of 99.2% (range, 95.2% to 100%) and a specificity of 96.5% (range, 89.2% to 100%) for identifying S. aureus, as well as a sensitivity of 94.3% (range, 87.5% to 100%) and a specificity of 97.8% (range, 96.1% to 100%) for identifying MRSA. Five of six cultures falsely reported as negative for MRSA by the GeneOhm assay were correctly identified as positive by the Xpert assay, while one culture falsely reported as negative for MRSA by the Xpert assay was correctly reported as positive by the GeneOhm assay

Rapid Screening of Urine Specimens for Bacteriuria by the Cellenium System

This study evaluated the performance of the Cellenium 160US urine screening system in comparison to that of the semiquantitative culture method. The performance characteristics of the Cellenium system for all clinically significant uropathogens were 89.5% sensitivity, 94.4% specificity, 97.1% negative predictive value, and 81% positive predictive value

Carbapenemase producing Enterobacterales at a large teaching hospital in Ohio: comparison to state surveillance and retrospective analysis of patient characteristics

Summary: Background: The presence of carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) around the world is increasing, particularly in healthcare settings. Surveillance testing for plasmid-mediated carbapenemase genes is necessary to tracking CP-CRE infections. Aim: In the state of Ohio, surveillance of carbapenem-resistant Enterobacterales (CRE) began in 2018, and to the authors' knowledge data on these cases has not been published to date. This study analyzed data on CRE from a large teaching hospital in Ohio, and by the Ohio Department of Health Laboratory (ODHL). Methods: Carbapenemase production was detected using mCIM, and plasmid-mediated carbapenemase genes were detected using rtPCR. Data was collected on 344 standard-of-care isolates from a large teaching hospital in Ohio, including data collected from chart review. Deidentified surveillance data on 4,391 CRE isolates was provided by the ODHL. Statistical analysis was performed using binary logistic regression. Findings: While KPC was the most common carbapenemase gene (n=1590), NDM (n=98), VIM (n=10), IMP (n=39) and OXA-48 (n=35) were also detected in the isolates studied. Klebsiella pneumoniae and Enterobacter cloacae were the most common CRE, and carbapenemase genes were most commonly detected in K. pneumoniae. Inpatient hospital stays and long-term care were associated with CP-CRE and were more common in women. Conclusion: Surveillance data shows that CP-CRE are present in Ohio, most commonly in Klebsiella pneumoniae. A better understanding of the prevalence of CRE, plasmid-mediated carbapenemase genes present, and the populations affected are important when tracking the spread of disease. Further study and surveillance of carbapenem-resistant organisms can provide a better understanding of their prevalence in the state

DNA Immunization with Hepatitis C Virus (HCV) Polycistronic Genes or Immunization by HCV DNA Priming-Recombinant Canarypox Virus Boosting Induces Immune Responses and Protection from Recombinant HCV-Vaccinia Virus Infection in HLA-A2.1-Transgenic Mice

We studied immune responses to hepatitis C virus (HCV) genes delivered as DNA encoding the entire HCV protein coding genome in two polycistronic plasmids encoding HCV capsid-E1-E2-NS2-NS3 and HCV NS3-NS4-NS5 in HLA-A2.1-transgenic mice. Immune responses to HCV DNA prime and recombinant canarypox virus boost were also studied with the above constructs. At 8 weeks after a canarypox virus boost, the DNA prime/canarypox virus boosting regimen induced potent cellular immune responses to HCV structural and nonstructural proteins on target cells expressing the HLA-A2.1 allele. High frequencies of gamma interferon-secreting cells, as detected by enzyme-linked immunospot assay, were obtained in response to several endogenously expressed HCV proteins. We also observed cytotoxic-T-lymphocyte reactivity in response to endogenously expressed HCV proteins in fresh spleen cells without in vitro expansion. Upon challenge with a recombinant vaccinia virus expressing HCV proteins at 2 months postimmunization, the HCV DNA prime/canarypox virus-immunized mice showed a complete reduction in vaccinia virus titers compared to HCV DNA prime/boost- and mock-immunized controls. Immune responses were still detectable 4 months after canarypox virus boost in immunized mice. Interestingly, at 10 months postimmunization (8 months after canarypox virus boost), the protection in HCV DNA prime/boost-immunized mice against recombinant HCV-vaccinia virus challenge was higher than that observed in HCV DNA prime/canarypox virus boost-immunized mice

Pseudo-Outbreak of Cupriavidus pauculus Infection at an Outpatient Clinic Related to Rinsing Culturette Swabs in Tap Water▿

Cupriavidus pauculus is a water microorganism rarely isolated from clinical specimens. We describe a pseudo-outbreak in which multiple strains that were associated with moistening of culturette swabs with tap water were isolated from a single clinic before collecting the patient specimen