Most strains of Papaya ringspot virus (PRSV) belong to type W, causing severe loss on cucurbits worldwide, or type P, devastating papaya in tropical areas. While the host range of PRSV W is limited to plants of the families Chenopodiaceae and Cucuribitaceae, PRSV P, in addition, infects plants of the family Caricaceae (papaya family). To investigate one or more viral genetic determinants for papaya infection, recombinant viruses were constructed between PRSV P-YK and PRSV W-CI. Host reactions to recombinant viruses indicated that the viral genomic region covering the C-terminal region (142 residues) of NIaVPg, full NIaPro, and N-terminal region (18 residues) of NIb, is critical for papaya infection. Sequence analysis of this region revealed residue variations at position 176 of NIaVPg and positions 27 and 205 of NIaPro between type P and W viruses. Host reactions to the constructed mutants indicated that the amino acid Lys27 of NIaPro determines the host-specificity of PRSV for papaya infection. Predicted three-dimensional structures of NIaPros of parental viruses suggested that Lys27 does not affect the protease activity of NIaPro. Recovery of the infected plants from certain papaya-infecting mutants implied involvement of other viral factors for enhancing virulence and adaptation of PRSV on papaya.

The diverse alleles of the katG gene associated with INH resistance are present in the M. tuberculosis isolates in Taiwan. These data may be applied to develop new probes for various alleles associated with INH resistance in order to increase the sensitivity for the detection of genetically diverse M. tuberculosis isolates in different geographic areas. The diversity of mutations can also provide information for investigating the evolutional lineages of M. tuberculosis isolates.

The most prevalent mutations of the rpoB gene were missense mutations in the critical codons, encoding Ser-531, Gln-513, Leu-533, Asp-516, and His-526. These mutations had high sensitivity and specificity for predicting the rifampicin-resistance of M. tuberculosis isolates. The resistance profiles and the frequencies of mutated codons of the rpoB gene varied in different geographic regions, indicating that resistance evolved under the selective pressure of the therapeutic regimens and the spread of different genetic clones.

Objectives: Medical devices and the hospital environment can be contaminated easily by multidrug-resistant bacteria. The effectiveness of cleaning practices is often suboptimal because environmental cleaning in hospitals is complex and depends on human factors, the physical and chemical characteristics of environment, and the viability of the microorganisms. Ultraviolet-C (UV-C) lamps can be used to reduce the spread of microorganisms. We evaluated the effectiveness of an ultraviolet-C (UV-C) device on terminal room cleaning and disinfection. Methods: The study was conducted at an ICU of a medical center in Taiwan. We performed a 3-stage evaluation for the effectiveness of UV-C radiation, including pre–UV-C radiation, UV-C radiation, and a bleaching procedure. The 3 stages of evaluation were implemented in the ICU rooms from which a patient had been discharged or transferred. We collected the data from adenosine triphosphate (ATP) bioluminescence testing, colonized strains, and their corresponding colony counts by sampling from the environmental surfaces and air. We tested 8 high-touch surfaces, including 2 sides of bed rails, headboards, footboards, bedside tables, monitors, pumping devices, IV stands, and oxygen flow meters. Results: In total, 1,696 environmental surfaces and 72 air samples were analyzed. The levels of ATP bioluminescence and colony counts of isolated bacteria decreased significantly after UV-C radiation and bleaching disinfection for both the environmental and air samples (P < .001). Resistant bacteria (vancomycin-resistant Enterococcus, VRE) were commonly isolated on the hard-to-clean surfaces of monitors, oxygen flow meters, and IV pumps. However, they were also eradicated (P < .001). Conclusions: UV-C can significantly reduce environmental contamination by multidrug-resistant microorganisms. UV-C is an effective device to assist staff in cleaning the hospital environment.