RESUMEN
On September 30, 2015, the New Jersey Department of Health (NJDOH) was notified by an out-of-state health services company that an experienced nurse had reused syringes for multiple persons earlier that day. This occurred at an employee influenza vaccination clinic on the premises of a New Jersey business that had contracted with the health services company to provide influenza vaccinations to its employees. The employees were to receive vaccine from manufacturer-prefilled, single-dose syringes. However, the nurse contracted by the health services company brought three multiple-dose vials of vaccine that were intended for another event. The nurse reported using two syringes she found among her supplies to administer vaccine to 67 employees of the New Jersey business. She reported wiping the syringes with alcohol and using a new needle for each of the 67 persons. One of the vaccine recipients witnessed and questioned the syringe reuse, and brought it to the attention of managers at the business who, in turn, reported the practice to the health services company contracted to provide the influenza vaccinations.
Asunto(s)
Vacunas contra la Influenza/administración & dosificación , Inyecciones/efectos adversos , Errores Médicos , Servicios de Salud del Trabajador , Servicios Contratados , Humanos , Licencia en Enfermería , New Jersey , Pautas de la Práctica en Enfermería/normasRESUMEN
Ralstonia solanacearum race 3 biovar 2 is a regulated quarantine pathogen that infects solanaceous hosts such as potato as well as geranium, where it causes either bacterial wilt (also known as Southern Wilt) or a symptomless latent infection. Geranium growers and government regulators need reliable detection methods to identify infected plant material before it is exported. We previously found that R. solanacearum-infected geranium plants can shed millions of bacteria in effluent water that flows from pots. We tested a nondestructive sampling method wherein effluent water from infected plants grown under commercial conditions was both dilution plated and filter concentrated for real-time polymerase chain reaction (PCR). Under field conditions in Guatemala, effluent shedding of infected geranium plants was highly variable. Comprehensive growth chamber studies confirmed that latently infected and mildly symptomatic geranium plants often but not invariably shed detectable numbers of bacteria in their effluent. At the peak of bacterial shedding, just under 90% of infected plants shed detectable bacteria whereas, at the lowest point, 44% shed detectable numbers of pathogen cells. Bacterial shedding peaked several weeks after inoculation regardless of whether plants were symptomatic or latently infected. Bacterial stem population sizes did not correlate with either effluent population sizes or disease index rating. Finally, we found that the effluent from geranium plants grown in volcanic rock scoria medium contains inhibitors that reduce the effectiveness of real-time PCR detection methods.
RESUMEN
An 8x draft genome was obtained and annotated for Ralstonia solanacearum race 3 biovar 2 (R3B2) strain UW551, a United States Department of Agriculture Select Agent isolated from geranium. The draft UW551 genome consisted of 80,169 reads resulting in 582 contigs containing 5,925,491 base pairs, with an average 64.5% GC content. Annotation revealed a predicted 4,454 protein coding open reading frames (ORFs), 43 tRNAs, and 5 rRNAs; 2,793 (or 62%) of the ORFs had a functional assignment. The UW551 genome was compared with the published genome of R. solanacearum race 1 biovar 3 tropical tomato strain GMI1000. The two phylogenetically distinct strains were at least 71% syntenic in gene organization. Most genes encoding known pathogenicity determinants, including predicted type III secreted effectors, appeared to be common to both strains. A total of 402 unique UW551 ORFs were identified, none of which had a best hit or >45% amino acid sequence identity with any R. solanacearum predicted protein; 16 had strong (E < 10(-13)) best hits to ORFs found in other bacterial plant pathogens. Many of the 402 unique genes were clustered, including 5 found in the hrp region and 38 contiguous, potential prophage genes. Conservation of some UW551 unique genes among R3B2 strains was examined by polymerase chain reaction among a group of 58 strains from different races and biovars, resulting in the identification of genes that may be potentially useful for diagnostic detection and identification of R3B2 strains. One 22-kb region that appears to be present in GMI1000 as a result of horizontal gene transfer is absent from UW551 and encodes enzymes that likely are essential for utilization of the three sugar alcohols that distinguish biovars 3 and 4 from biovars 1 and 2.
Asunto(s)
Sistemas de Lectura Abierta/genética , Ralstonia solanacearum/clasificación , Ralstonia solanacearum/genética , Arginina , Genes Bacterianos , Genoma Bacteriano/genética , Familia de Multigenes , Regiones Promotoras Genéticas , Profagos , Transporte de Proteínas , Ralstonia solanacearum/patogenicidad , Análisis de Secuencia de ADN , Especificidad de la Especie , Factores de VirulenciaRESUMEN
ABSTRACT Southern wilt of geraniums (Pelargonium hortorum), caused by the soilborne bacterium Ralstonia solanacearum race 3 biovar 2 (R3bv2), has inflicted significant economic losses when geranium cuttings latently infected with this quarantine pest were imported into the United States. Little is known about the interaction between R. solanacearum and this ornamental host. Using UW551, a virulent R3bv2 geranium isolate from a Kenyan geranium, we characterized development of Southern wilt disease and R3bv2 latent infection on geranium plants. Following soil inoculation, between 12 and 26% of plants became latently infected, carrying average bacterial populations of 4.8 x 10(8) CFU/g of crown tissue in the absence of visible symptoms. Such latently infected plants shed an average of 1.3 x 105 CFU/ml in soil run-off water, suggesting a non-destructive means of testing pools of asymptomatic plants. Similarly, symptomatic plants shed 2 x 10(6) CFU/ml of run-off water. A few hundred R. solanacearum cells introduced directly into geranium stems resulted in death of almost all inoculated plants. However, no disease transmission was detected after contact between wounded leaves. Increasing temperatures to 28 degrees C for 2 weeks did not convert all latently infected plants to active disease, although disease development was temperature dependent. Holding plants at 4 degrees C for 48 h, a routine practice during geranium cutting shipment, did not increase frequency of latent infections. R. solanacearum cells were distributed unevenly in the stems and leaves of both symptomatic and latently infected plants, meaning that random leaf sampling is an unreliable testing method. UW551 also caused potato brown rot and bacterial wilt of tomato, surpassing race 1 strain K60 in virulence on tomato at the relatively cool temperature of 24 degrees C.
RESUMEN
Multidrug efflux pumps (MDRs) are hypothesized to protect pathogenic bacteria from toxic host defense compounds. We created mutations in the Ralstonia solanacearum acrA and dinF genes, which encode putative MDRs in the broad-host-range plant pathogen. Both mutations reduced the ability of R. solanacearum to grow in the presence of various toxic compounds, including antibiotics, phytoalexins, and detergents. Both acrAB and dinF mutants were significantly less virulent on the tomato plant than the wild-type strain. Complementation restored near-wild-type levels of virulence to both mutants. Addition of either dinF or acrAB to Escherichia coli MDR mutants KAM3 and KAM32 restored the resistance of these strains to several toxins, demonstrating that the R. solanacearum genes can function heterologously to complement known MDR mutations. Toxic and DNA-damaging compounds induced expression of acrA and dinF, as did growth in both susceptible and resistant tomato plants. Carbon limitation also increased expression of acrA and dinF, while the stress-related sigma factor RpoS was required at a high cell density (>10(7) CFU/ml) to obtain wild-type levels of acrA expression both in minimal medium and in planta. The type III secretion system regulator HrpB negatively regulated dinF expression in culture at high cell densities. Together, these results show that acrAB and dinF encode MDRs in R. solanacearum and that they contribute to the overall aggressiveness of this phytopathogen, probably by protecting the bacterium from the toxic effects of host antimicrobial compounds.
Asunto(s)
Proteínas Bacterianas/genética , Farmacorresistencia Microbiana/genética , Proteínas de Transporte de Membrana/genética , Ralstonia solanacearum/genética , Ralstonia solanacearum/patogenicidad , Solanum lycopersicum/microbiología , Antibacterianos/toxicidad , Clonación Molecular , Cartilla de ADN , Detergentes/toxicidad , Escherichia coli , Glucuronidasa , Mutagénesis , Reacción en Cadena de la Polimerasa , Ralstonia solanacearum/efectos de los fármacos , Sesquiterpenos , Terpenos/toxicidad , Virulencia , FitoalexinasRESUMEN
To identify secreted virulence factors involved in bacterial wilt disease caused by the phytopathogen Ralstonia solanacearum, we mutated tatC, a key component of the twin-arginine translocation (Tat) secretion system. The R. solanacearum tatC mutation was pleiotropic; its phenotypes included defects in cell division, nitrate utilization, polygalacturonase activity, membrane stability, and growth in plant tissue. Bioinformatic analysis of the R. solanacearum strain GMI1000 genome predicted that this pathogen secretes 70 proteins via the Tat system. The R. solanacearum tatC strain was severely attenuated in its ability to cause disease, killing just over 50% of tomato plants in a naturalistic soil soak assay where the wild-type parent killed 100% of the plants. This result suggested that elements of the Tat secretome may be novel bacterial wilt virulence factors. To identify contributors to R. solanacearum virulence, we cloned and mutated three genes whose products are predicted to be secreted by the Tat system: RSp1521, encoding a predicted AcvB-like protein, and two genes, RSc1651 and RSp1575, that were identified as upregulated in planta by an in vivo expression technology screen. The RSc1651 mutant had wild-type virulence on tomato plants. However, mutants lacking either RSp1521, which appears to be involved in acid tolerance, or RSp1575, which encodes a possible amino acid binding protein, were significantly reduced in virulence on tomato plants. Additional bacterial wilt virulence factors may be found in the Tat secretome.
Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Membrana/genética , Enfermedades de las Plantas/microbiología , Ralstonia solanacearum/genética , Solanum lycopersicum/microbiología , Factores de Virulencia/metabolismo , Proteínas Bacterianas/genética , Secuencia de Bases , Clonación Molecular , Biología Computacional , Cartilla de ADN/genética , Prueba de Complementación Genética , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación/genética , Ralstonia solanacearum/patogenicidad , Análisis de Secuencia de ADN , Factores de Virulencia/genéticaRESUMEN
Access to health care, the timely use of personal health services to achieve the best possible health outcomes, remains a fundamental problem for children in the United States. To date, research and interventions addressing children's access to care have largely focused on policy-level features of the health care system (such as health insurance and geographic availability of providers) with some, although limited, success. Ultimately, access to health care implies entry into the health care system. Practice scheduling systems are the point of entry to primary care health services for children and thus directly determine access to care in pediatric and family medicine practices. Here we explore the rationale for improving access to care for children from an additional angle: through improving practice scheduling systems. It is our hypothesis that some of the most promising contemporary interventions to improve children's access involve improving primary care scheduling systems. These approaches should complement successful policy-level interventions to improve access to care for children.