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Biomedical subjects

Ken B Waites

Publications and source records attributed to Ken B Waites.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of 3 methods of bladder irrigation to treat bacteriuria in persons with neurogenic bladder.

BACKGROUND/OBJECTIVE: We conducted a randomized, double-blind comparison of twice daily bladder irrigation using 1 of 3 different solutions in community-residing persons with neurogenic bladder who used indwelling catheters to evaluate efficacy in treatment of bacteriuria. METHODS: Eighty-nine persons with bacteriuria were randomized to irrigate their bladders twice daily for 8 weeks with 30 mL of (a) sterile saline, (b) acetic acid, or (c) neomycin-polymyxin solution. Urinalysis, cultures, and antimicrobial susceptibility tests were performed at baseline and weeks 2, 4, and 8 to determine the extent to which each of the solutions affected numbers and types of bacteria, urinary pH, urinary leukocytes, and generation of antimicrobial-resistant organisms. RESULTS: Bladder irrigation was well tolerated with the exception of 3 participants who had bladder spasms. None of the 3 irrigants had a detectable effect on the degree of bacteriuria or pyuria in 52 persons who completed the study protocol. A significant increase in urinary pH occurred in all 3 groups. No significant development of resistance to oral antimicrobials beyond what was observed at baseline was detected. CONCLUSIONS: Bladder irrigation was generally well tolerated for 8 weeks. No advantages were detected for neomycin-polymyxin or acetic acid over saline in terms of reducing the urinary bacterial load and inflammation. We cannot recommend bladder irrigation as a means of treatment for bacteriuria in persons with neurogenic bladder.

Acetic Acid↗
PubMed2006

Antimicrobial susceptibility among pathogens collected from hospitalized patients in the United States and in vitro activity of tigecycline, a new glycylcycline antimicrobial.

The activities of tigecycline and comparators against isolates collected from 76 U.S. centers between January 2004 and September 2005 were assessed. Tigecycline MIC(90)s were < or =2 microg/ml for Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, and Streptococcus agalactiae.

Anti-Bacterial Agents↗
PubMed2006

Nosocomial spread of Enterococcus faecium resistant to vancomycin and linezolid in a tertiary care medical center.

In May 2004 our institution encountered its first clinical isolate of linezolid-resistant, vancomycin-resistant Enterococcus faecium (LRVRE). Between October 2004 and July 2005, 40 patients from whom LRVRE organisms were recovered in clinical specimens were characterized. Epidemiologic investigation and pulsed-field gel electrophoresis patterns indicated a clonal outbreak related to nosocomial spread.

Academic Medical Centers↗
PubMed2006

Prevalence of inducible clindamycin resistance among community- and hospital-associated Staphylococcus aureus isolates.

Methicillin-resistant Staphylococcus aureus (MRSA) infections have become common among both hospitalized and nonhospitalized patients. Optimal outpatient therapy for MRSA infections has yet to be determined, but this matter is complicated by the possibility of inducible macrolide-lincosamide-streptogramin B resistance (MLSBi). We studied the prevalence of MLSBi in community- and hospital-associated S. aureus isolates and the prevalence of community-associated MRSA (CA-MRSA) and identified clinical predictors of CA-MRSA and MLSBi. Among 402 S. aureus isolates, the overall prevalence of MLSBi was 52%, with 50% of MRSA and 60% of methicillin-susceptible S. aureus isolates exhibiting MLSBi. CA-MRSA represented 14% of all isolates and had a lower prevalence of MLSBi than hospital-associated MRSA (33% versus 55%). The presence of skin or soft-tissue infection was predictive for CA-MRSA, and the presence of a comorbidity was predictive for MLSBi. Due to the low prevalence of MLSBi among CA-MRSA isolates, clindamycin remains a useful option for outpatient therapy.

Anti-Bacterial Agents↗
PubMed2005

Poliovirus replicons encoding the B subunit of Helicobacter pylori urease protect mice against H. pylori infection.

We developed a novel vaccine for Helicobacter pylori based on a poliovirus vector in which capsid genes were replaced with the gene for the B subunit of H. pylori urease (UreB). Mice were vaccinated with UreB or control (L1) replicon and challenged with H. pylori. Twenty percent of mice vaccinated prophylactically with UreB, but 80% vaccinated with L1, and then challenged with H. pylori became infected (P = 0.003). Seventy-three percent of mice with established H. pylori infection vaccinated therapeutically with UreB replicon cleared their infection compared to 33% vaccinated with L1 (P = 0.067). In therapeutically vaccinated mice with residual infection, UreB-vaccinated animals had fewer H. pylori than L1-vaccinated mice (P < 0.05). Anti-urease antibody titres in prophylactically, but not therapeutically, vaccinated mice were markedly higher in animals that received UreB versus L1 replicon (P = 0.01). Vaccination with poliovirus vector containing the gene for the B subunit of H. pylori urease provides significant prophylactic and strong therapeutic protection against H. pylori in mice.

Animals↗
PubMed2005

Effective communication of antimicrobial susceptibility data by pathologists to clinicians.

As antimicrobial-resistant gram-positive and gram-negative bacterial infections continue to emerge over time, influenced by selective pressure, and the costs of treating these infections increase, the ability of microbiology laboratories to accurately detect drug resistant bacteria and communicate susceptibility test results effectively to clinicians in a timely manner is more important than ever. Ongoing cooperation and coordination of activities among clinical pathologists, technical personnel, pharmacy, clinical services, and infection control using up-to-date laboratory methodologies and interpretive criteria to develop laboratory reports that are transmitted efficiently through computerized communication systems for use within each particular institution are essential to provide optimum patient care, control resistance, and conserve resources.

Clinical Laboratory Information Systems↗
PubMed2005

Nosocomial ventriculitis due to Roseomonas gilardii complicating subarachnoid haemorrhage.

Roseomonas gilardii is a pink-pigmented, non-fermentative, Gram-negative coccobacillus that has been recognized as a rare cause of human infections. We report the first case of ventriculitis caused by R. gilardii in a 54-year-old man with a subarachnoid haemorrhage secondary to a vertebral artery aneurysm; discuss previous reports of this organism as a nosocomial and community-acquired pathogen, laboratory diagnosis, and patient management.

Cerebral Ventricles↗
PubMed2005

Critical appraisal of the role of Ureaplasma in the development of bronchopulmonary dysplasia with metaanalytic techniques.

BACKGROUND: Controversy exists over whether or not Ureaplasma colonization or infection of the respiratory tract contributes to the development of bronchopulmonary dysplasia (BPD). Because BPD is a major cause of morbidity and mortality in preterm infants and a potential therapeutic intervention with antimicrobials is possible, we sought to evaluate and critique the current medical literature and to document the reported association between Ureaplasma and BPD. METHODS: We analyzed all peer-reviewed articles and previous reviews including cross-references that reported Ureaplasma respiratory tract colonization or infection and development of BPD in neonates published from January 1966 to December 2004. Inclusion criteria included a cohort limited to all neonatal intensive care unit admissions or all colonized infants, articles that did not define a numerator and a denominator for BPD and Ureaplasma or that included patients from other reports were excluded from the analysis. We evaluated BPD at 28 postnatal days (BPD28) or 36 weeks post-menstrual age (BPD36). RESULTS: Twenty-three studies with an aggregate of 2216 infants reported BPD28, and 8 studies with 751 infants reported BPD36. Although there was significant association between Ureaplasma colonization and both BPD28 and BPD36, there was substantial heterogeneity (Q test statistic, P < 0.01). We therefore focused on describing the study characteristics associated with an increased relative proportion of BPD. The greatest contribution to effect was from the studies enrolling fewer than 100 infants. CONCLUSION: Ureaplasma colonization is associated with higher reported rates of BPD, but the greatest reported effect is seen in small studies; reporting bias may be partially responsible for this effect.

Bronchopulmonary Dysplasia↗
PubMed2005

Comparative in vitro activities of investigational peptide deformylase inhibitor NVP LBM-415 and other agents against human mycoplasmas and ureaplasmas.

Peptide deformylase inhibitor LBM-415 and seven other drugs were tested against Mycoplasma pneumoniae (100 isolates), Mycoplasma hominis (20 isolates), Mycoplasma fermentans (10 isolates), and Ureaplasma species (50 isolates). LBM-415 was active against M. pneumoniae (MICs, <or=0.008 microg/ml). It showed no activity against M. hominis and M. fermentans and modest activity against Ureaplasma spp.

Amidohydrolases↗
PubMed2005

Mycoplasmas and ureaplasmas as neonatal pathogens.

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.

Adult↗
PubMed2005

Rapid multiplex assay for serotyping pneumococci with monoclonal and polyclonal antibodies.

We have developed and characterized a rapid semiautomated pneumococcal serotyping system incorporating a pneumococcal lysate preparation protocol and a multiplex serotyping assay. The lysate preparation incorporates a bile solubility test to confirm pneumococcal identification that also enhances assay specificity. The multiplex serotyping assay consists of 24 assays specific for 36 serotypes: serotypes 1, 2, 3, 4, 5, 6A, 6B, 7A/7F, 8, 9L/9N, 9V, 10A/10B/39/(33C), 11A/11D/11F, 12A/12B/12F, 14, 15B/(15C), 17F, 18C, 19A, 19F, 20, 22A/22F, 23F, and 33A/33F. The multiplex assay requires a flow cytometer, two sets of latex particles coated with pneumococcal polysaccharides, and serotype-specific antibodies. Fourteen newly developed monoclonal antibodies specific for common serotypes and a pool of polyclonal rabbit sera for some of the less-common serotypes are used. The two monoclonal antibodies specific for serotypes 18C and 23F recognize serotype-specific epitopes that have not been previously described. These monoclonal antibodies make the identification of the 14 common serotypes invariant. The specificity of the serotyping assay is fully characterized with pneumococci of all known (i.e., 90) serotypes. The assay is sensitive enough to use bacterial lysates diluted 20 fold. Our serotyping system can identify not only all the serotypes in pneumococcal vaccines but also most (>90%) of clinical isolates. This system should be very useful in serotyping clinical isolates for evaluating pneumococcal vaccine efficacy.

Animals↗
PubMed2005

Relative fitness of fluoroquinolone-resistant Streptococcus pneumoniae.

Fluoroquinolone resistance in Streptococcus pneumoniae is primarily mediated by point mutations in the quinolone resistance-determining regions of gyrA and parC. Antimicrobial resistance mutations in housekeeping genes often decrease fitness of microorganisms. To investigate the fitness of quinolone-resistant S. pneumoniae (QRSP), the relative growth efficiencies of 2 isogenic QRSP double mutants were compared with that of their fluoroquinolone-susceptible parent, EF3030, by using murine nasopharyngeal colonization and pneumonia models. Strains containing the GyrA: Ser81Phe, ParC: Ser79Phe double mutations, which are frequently seen in clinical QRSP, competed poorly with EF3030 in competitive colonization or competitive lung infections. However, they efficiently produced lung infection even in the absence of EF3030. The strain containing the GyrA: Ser81Phe, ParC: Ser79Tyr double mutations, which is seen more frequently in laboratory-derived QRSP than in clinical QRSP, demonstrated reduced nasal colonization in competitive or noncompetitive lung infections. However, the strain was equally able to cause competitive or noncompetitive lung infections as well as EF3030.

Animals↗
PubMed2004

Microbiology of the urethra and perineum and its relationship to bacteriuria in community-residing men with spinal cord injury.

OBJECTIVE: Reasons why some persons with spinal cord injury (SCI) experience recurrent urinary tract infections more than others are poorly understood. We performed a prospective study of bacterial flora of the urethra and perineum in men with and without bacteriuria to understand more completely the relationship between bacterial colonization and invasion of the urinary tract. METHODS: Urine, urethra, and perineum cultures were obtained from 70 men. Microbial flora of these sites was compared for men with and without bacteriuria. RESULTS: Urine colony count was 0 in 16 (22.9%) men. Perinea in 2 men (12.5%) and urethras in 6 men (37.5%) were colonized with various gram-negative bacilli, enterococci, and/or Staphylococcus aureus. Among 54 (77.1%) men with bacteriuria, uropathogens were shown in the perineum in 31 (57.4%) and in the urethra in 46 (85.2%). In 40 (74.1%) of men with bacteriuria, at least one bacterial species present in the urine was also found in the urethra and/or perineum. Differences in the occurrence of uropathogens in men with and without bacteriuria were statistically significant, and organisms were present in higher numbers in men with bacteriuria. CONCLUSION: Men with SCI who have bacteriuria are significantly more likely to be colonized in the distal urethra and perineum with uropathogens that are often present in the urine in comparison with men without bacteriuria.

Adult↗
PubMed2004

Effect of cranberry extract on bacteriuria and pyuria in persons with neurogenic bladder secondary to spinal cord injury.

OBJECTIVE: To determine whether antibacterial effects of cranberry extract will reduce or eliminate bacteriuria and pyuria in persons with spinal cord injury (SCI). DESIGN: Randomized, double-blind, placebo-controlled study. PARTICIPANTS: Participants were people with SCI residing in the community who were 1 year or longer postinjury with neurogenic bladder managed by intermittent catheterization or external collection device and a baseline urine culture demonstrating at least 10(5) colonies per milliliter of bacteria. METHODS: Each participant ingested 2 g of concentrated cranberry juice or placebo in capsule form daily for 6 months. Baseline urinalysis and cultures were performed at the time of the initial clinic visit and monthly for 6 months. Microbiologic data were evaluated using analysis of variance with repeated measures. RESULTS: Twenty-six persons received cranberry extract and 22 persons received placebo. There were no differences or trends detected between participants and controls with respect to number of urine specimens with bacterial counts of at least 10(4) colonies per milliliter, types and numbers of different bacterial species, numbers of urinary leukocytes, urinary pH, or episodes of symptomatic urinary tract infection. CONCLUSION: Cranberry extract taken in capsule form did not reduce bacteriuria and pyuria in persons with SCI and cannot be recommended as a means to treat these conditions.

Adult↗
PubMed2004

Mycoplasma pneumoniae and its role as a human pathogen.

Mycoplasma pneumoniae is a unique bacterium that does not always receive the attention it merits considering the number of illnesses it causes and the degree of morbidity associated with it in both children and adults. Serious infections requiring hospitalization, while rare, occur in both adults and children and may involve multiple organ systems. The severity of disease appears to be related to the degree to which the host immune response reacts to the infection. Extrapulmonary complications involving all of the major organ systems can occur in association with M. pneumoniae infection as a result of direct invasion and/or autoimmune response. The extrapulmonary manifestations are sometimes of greater severity and clinical importance than the primary respiratory infection. Evidence for this organism's contributory role in chronic lung conditions such as asthma is accumulating. Effective management of M. pneumoniae infections can usually be achieved with macrolides, tetracyclines, or fluoroquinolones. As more is learned about the pathogenesis and immune response elicited by M. pneumoniae, improvement in methods for diagnosis and prevention of disease due to this organism may occur.

Asthma↗