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William Kabat

Publications and source records attributed to William Kabat.

7 recordsLinked to original sources
PubMed2004

Community-based surveillance in the united states of macrolide-resistant pediatric pharyngeal group A streptococci during 3 respiratory disease seasons.

BACKGROUND: In 2001, a total of 48% of pharyngeal group A streptococci (GAS) from Pittsburgh children were macrolide resistant. We assessed macrolide resistance, resistance genes, and emm types among GAS in the United States. METHODS: In prospective, multicenter, community-based surveillance of pharyngeal GAS recovered from children 3-18 years old during 3 respiratory seasons (the 2000-2001 season, the 2001-2002 season, and the 2002-2003 season), GAS were tested for macrolide resistance and underwent emm gene sequencing. Macrolide-resistant GAS were tested for resistance to clindamycin, and resistance genes were determined. RESULTS: Erythromycin resistance was observed in 4.4% of isolates from the 2000-2001 season, 4.3% from the 2001-2002 season, and 3.8% from the 2002-2003 season (P=.80). Clindamycin resistance was found in 1.04% of isolates; annual rates of clindamycin resistance were stable (P=.75). The predominant resistance genotype each year was mef A (65%-76.9%; overall, 70.3%). Resistant isolates included strains representing 8-11 different emm types each year. Heterogeneity of emm subtypes, resistance genes, and clindamycin resistance was evident among resistant isolates within some emm types. Geographic variability in resistance rates was present each year. CONCLUSIONS: The macrolide resistance rate among pharyngeal GAS was <5% and was stable over the 3 seasons. However, rates varied among sites each year. There was no evidence of spread of a specific resistant clone, increasing clindamycin resistance, or escalation in median erythromycin MICs.

Child↗
PubMed2004

Group A streptococcal pharyngitis serotype surveillance in North America, 2000-2002.

Geographic and interseasonal heterogeneity of pharyngeal group A streptococcal (GAS) genotypes (emm types) is poorly characterized. We evaluated emm type and subtype distribution among pediatric pharyngitis isolates obtained from 9 sites in the United States during 2000-2001 (year 1) and from 10 sites in the United States and 1 site in Canada during 2001-2002 (year 2). The 7 predominant types were the same in both years, although their order changed. emm 12, 1, and 28 accounted for 49.2% of year 1 isolates, and emm 1, 12, and 4 accounted for 47.1% of year 2 isolates; 6 types accounted for 72.1% in year 1 and 69.4% in year 2. From year 1 to year 2, the proportions of emm 12 and 28 decreased and emm 1 and 6 increased. Striking intersite and interseasonal variations in the distribution of predominant emm types were observed. We conclude that the most-predominant GAS genotypes were similar for each year despite fluctuations, that intersite and intrasite variations in the distribution of emm types were apparent, and that emm type surveillance is needed as M protein vaccine development proceeds.

Adolescent↗
PubMed2004

Antimicrobial susceptibilities of invasive pediatric Abiotrophia and Granulicatella isolates.

Abiotrophia and Granulicatella species have been associated with various infections. Antimicrobial susceptibility data for these nutritionally variant streptococcus-like organisms, especially for pediatric isolates, are very limited. Little is known about the genetic bases of their resistance mechanisms. We report the results of identification to bacterial species level, antimicrobial susceptibility testing, macrolide resistance testing, and detection of genes encoding that resistance for a collection of 15 pediatric clinical isolates from normally sterile sites. Our results indicate that the prevalence of beta-lactam and macrolide resistance is high and that both erm and mef are found in these isolates.

Base Sequence↗
PubMed2004

Anti-Vpr activity of a yeast chaperone protein.

Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) exerts multiple effects on viral and host cellular activities during viral infection, including nuclear transport of the proviral integration complex, induction of cell cycle G(2) arrest, and cell death. In this report, we show that a fission yeast chaperone protein Hsp16 inhibits HIV-1 by suppressing these Vpr activities. This protein was identified through three independent genome-wide screens for multicopy suppressors of each of the three Vpr activities. Consistent with the properties of a heat shock protein, heat shock-induced elevation or overproduction of Hsp16 suppressed Vpr activities through direct protein-protein interaction. Even though Hsp16 shows a stronger suppressive effect on Vpr in fission yeast than in mammalian cells, similar effects were also observed in human cells when fission yeast hsp16 was expressed either in vpr-expressing cells or during HIV-1 infection, indicating a possible highly conserved Vpr suppressing activity. Furthermore, stable expression of hsp16 prior to HIV-1 infection inhibits viral replication in a Vpr-dependent manner. Together, these data suggest that Hsp16 inhibits HIV-1 by suppressing Vpr-specific activities. This finding could potentially provide a new approach to studying the contribution of Vpr to viral pathogenesis and to reducing Vpr-mediated detrimental effects in HIV-infected patients.

Cell Death↗
PubMed2002

Quantification of human immunodeficiency virus type 1 proviral DNA by using TaqMan technology.

A protocol for quantification of human immunodeficiency virus type 1 (HIV-1) proviral DNA with the TaqMan technology was developed and validated. The assay was specific for HIV-1, with an analytic sensitivity of 10 copies and a linear dynamic range of >6 logs. Viral RNA levels, when at a stable state, were highly correlated with proviral DNA levels in 80 specimens of 18 HIV-infected children.

Antiretroviral Therapy, Highly Active↗
PubMedDate not supplied

Update on the laboratory diagnosis and monitoring of HIV infection.

In China, the estimated number of HIV infected cases is approaching one million. Although public education has been initiated for awareness and behavioral modification for this devastating infection, better diagnostic methods are needed to identify infected persons and manage infection. Simple and more accurate diagnostic tools have become available, particularly for early detection and to monitor treatment in those who receive anti-retroviral treatment. In this short review, we summarize some of the common and new methodologies that can be used in clinical laboratories, in the field, or in private laboratories. These range from simple antibody tests to more sophistical methods that are used to monitor disease progression and identify drug resistance. These tools can assist physicians, medical practitioners, and laboratory personnel to select suitable diagnostic tools for the diagnosis, blood screening, monitoring of disease progression, and for detection of drug resistance to anti-retroviral therapies.

HIV↗