Identification and characterization of novel catalytic bioscavengers of organophosphorus nerve agents.

In an effort to discover novel catalytic bioscavengers of organophosphorus (OP) nerve agents, cell lysates from a diverse set of bacterial strains were screened for their capacity to hydrolyze the OP nerve agents VX, VR, and soman (GD). The library of bacterial strains was identified using both random and rational approaches. Specifically, two representative strains from eight categories of extremophiles were chosen at random.

Nontypeable pneumococcal isolates among navajo and white mountain apache communities: are these really a cause of invasive disease?

Background: Pneumococci could evade pneumococcal conjugate vaccines (PCV) by modifying, mutating, or deleting vaccine-serotype capsule genes or by downregulating capsule production. We sought to assess whether pneumococci that are nontypeable (NT) by the Quellung reaction truly lack capsule genes or are failing to produce capsule in vitro.

Methods: We applied multilocus sequence typing and a microarray for detection of pneumococcal polysaccharide capsule biosynthesis genes to NT carriage (children aged <5 years; years 1997-2000, 2006-2008) and NT invasive disease (IPD) (all ages; years 1994-2007) isolates from Native American communities.

Impact of more than a decade of pneumococcal conjugate vaccine use on carriage and invasive potential in Native American communities.

Background: We assessed the impact of 12 years of pneumococcal conjugate vaccine (PCV7) use on pneumococcal nasopharyngeal carriage and serotype-specific invasive disease potential among Native Americans.

Methods: Families were enrolled in a carriage study from 2006 to 2008; nasopharyngeal specimens and risk factor information were collected monthly for 7 visits. Pneumococcal carriage prevalence was compared with that before (1998-2000) and during (2001-2002) PCV7 introduction.

Pneumococcal sequence type replacement among American Indian children: a comparison of pre- and routine-PCV7 eras.

Background: Multi-locus sequence typing (MLST) of pneumococcal isolates collected during an efficacy trial of the 7-valent pneumococcal conjugate vaccine (PCV7) among Navajo and White Mountain Apache children from 1998 to 2000 showed a non-differential expansion of pre-existing sequence types (STs) and only one capsule-switching event in the PCV7-randomized communities. PCV7 was introduced as a routine infant vaccine in October 2000. We assessed variability in PCV7 effectiveness and mechanisms of ST replacement after prolonged routine PCV7 use.

Marked increase in biofilm-derived rough pneumococcal variants and rifampin-resistant strains not due to hex gene mutations.

Otitis, pneumonia, and meningitis are tissue-based pneumococcal infections that can be associated with biofilms. The emergence of phenotypic rough variants, also known as acapsular small-colony variants, is essential for pneumococcal biofilm formation. These rough variants can increase nearly 100-fold in biofilms over time and can arise through single nucleotide polymorphisms (SNPs), deletions, or tandem duplications in the first gene of the capsular operon, cps3D.