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R Frothingham

Publications and source records attributed to R Frothingham.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Identification of a W variant outbreak of Mycobacterium tuberculosis via population-based molecular epidemiology.

CONTEXT: Typing of Mycobacterium tuberculosis could provide a more sensitive means of identifying outbreaks than use of conventional surveillance techniques alone. Variants of the New York City W strain of M tuberculosis were identified in New Jersey. OBJECTIVE: To describe the spread of the W family of M tuberculosis strains in New Jersey identified by molecular typing and surveillance data. DESIGN: Population-based cross-sectional study. SETTING AND SUBJECTS: All incident culture-positive tuberculosis cases reported in New Jersey from January 1996 to September 1998, for which the W family was defined by insertion sequence (IS) IS6110 DNA fingerprinting, polymorphic GC-rich repetitive sequence (PGRS) typing, spacer oligotyping (spoligotyping), and variable number tandem repeat (VNTR) analysis. MAIN OUTCOME MEASURE: Identification and characterization of W family clones supplemented by surveillance data. RESULTS: Isolates from 1207 cases were analyzed, of which 68 isolates (6%) belonged to the W family based on IS6110 and spoligotype hybridization patterns. The IS6110 hybridization patterns or fingerprints revealed that43 patients (designated group A) shared a unique banding motif not present in other W family isolates. Strains collected from the remaining 25 patients (designated group B), while related to W, displayed a variety of IS6110 patterns and did not share this motif. The PGRS and VNTR typing confirmed the division of the W family into groups A and B and again showed group A strains to be closely related and group B strains to be more diverse. The demographic characteristics of individuals from groups A and B were specific and defined. Group A patients were more likely than group B patients to be US born (91 % vs 24%, P<.001), black (76% vs 16%, P<.001), human immunodeficiency virus positive (40% vs 0%, P = .007), and residents of urban northeast New Jersey counties (P<.001). Patients with group B strains were primarily non-US born, of Asian descent, and more dispersed throughout New Jersey. No outbreak had been detected using conventional surveillance alone. CONCLUSIONS: The implementation of multiple molecular techniques in conjunction with surveillance data enabled us to identify a previously undetected outbreak in a defined geographical setting. The outbreak isolates comprise members of a distinct branch of the W family phylogenetic lineage. The use of molecular strain typing provides a proactive approach that may be used to initiate, and not just augment, traditional surveillance outbreak investigations.

Adult↗
PubMedDate not supplied

Molecular identification of streptomycin monoresistant Mycobacterium tuberculosis related to multidrug-resistant W strain.

A distinct branch of the Mycobacterium tuberculosis W phylogenetic lineage (W14 group) has been identified and characterized by various genotyping techniques. The W14 group comprises three strain variants: W14, W23, and W26, which accounted for 26 clinical isolates from the New York City metropolitan area. The W14 group shares a unique IS6110 hybridizing banding motif as well as distinct polymorphic GC-rich repetitive sequence and variable number tandem repeat patterns. All W14 group members have high levels of streptomycin resistance. When the streptomycin resistance rpsL target gene was sequenced, all members of this strain family had an identical mutation in codon 43. Patients infected with the W14 group were primarily of non- Hispanic black origin (77%); all were US-born. Including HIV positivity, 84% of the patients had at least one known risk factor for tuberculosis.

Adult↗
PubMedDate not supplied

Mycobacteria: treatment approaches and mechanisms of resistance.

First-line drugs for tuberculosis treatment include isoniazid, rifampin, ethambutol, streptomycin, and pyrazinamide. Molecular mechanisms for resistance to each of these drugs have been elucidated. In every case, resistance is conferred by mutations in existing genes, not by the acquisition of new genetic material. Drug resistance is a major problem worldwide, but the rates vary widely among countries and within countries. Acquired resistance in previously-treated patients is much more common than primary resistance in patients with no previous treatment. High rates of acquired resistance have been reported from referral centers in Saudi Arabia and Lebanon. Successful TB treatment requires prolonged therapy with at least two active drugs. Directly-observed therapy (DOT) improves success rates and reduces the risk of acquired resistance. TB due to susceptible strains can be cured in over 95% of cases.

Adult↗