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B Mathema

Publications and source records attributed to B Mathema.

10 recordsLinked to original sources
PubMed2003

Prevalence of agr specificity groups among Staphylococcus aureus strains colonizing children and their guardians.

PCR-based assays were used to evaluate agr locus nucleotide polymorphism for the identification of agr autoinducer receptor specificity groups within a population of Staphylococcus aureus isolates colonizing children and their guardians. All isolates could be assigned to one of three major agr groups that had similar prevalences, regardless of whether isolates were implicated in transmission of S. aureus within families. Among healthy carriers, agr groups I to III appear to be equally fit, which may reflect selection for the coexistence of S. aureus strains in a population.

Adult↗
PubMed2001

Prevalence of vaginal colonization by drug-resistant Candida species in college-age women with previous exposure to over-the-counter azole antifungals.

We enrolled 382 college-age women in a cross-sectional survey to investigate the relationship between use of over-the-counter (OTC) azole-based antifungal drugs and vaginal colonization by drug-resistant Candida. This study showed no correlation (P=.506) between previous OTC exposure and colonization of drug-resistant Candida in vaginal flora. However, a small number of resistant Candida species isolates were obtained from women with a history of multiple exposures to OTC antifungals; given the widespread use of these products, this may be an emerging concern.

Adult↗
PubMed2001

Molecular epidemiology of tuberculosis among eight hospitals in New York City, 1996-1997.

OBJECTIVE: To determine the molecular epidemiology of tuberculosis isolated from patients cared for at eight hospitals scattered throughout New York City. MATERIALS AND METHODS: Cases of tuberculosis occurring in 1996 and 1997 at collaborating hospitals were identified, and demographic data were extracted from patient charts. All available isolates were analyzed by IS6110 for genetic relatedness. The molecular fingerprints were compared both to each other and to the larger repository of strains from New York City developed and maintained at the Public Health Research Institute. RESULTS: One hundred and eighty cases were fully characterized. Compared with New York City cases, study patients were more likely to be Asian and less likely to be non-Hispanic blacks. Overall, 97 (54%) of the cases were clustered with respect to other study strains or with respect to the other New York City isolates. Clustered strains were significantly more likely to be from non-Hispanic blacks or patients born in the United States. The largest cluster (n = 17) was the "W" strain previously associated with an outbreak of multidrug-resistant tuberculosis in New York City. In the current study, the majority of W strain isolates were fully drug-susceptible. CONCLUSIONS: High rates of genetically related tuberculosis continue to occur among patients in New York City, in spite of improved control of nosocomial outbreaks and dramatic decreases in the overall case rates. The use of molecular techniques to suggest patterns of transmission has become essential in developing and assessing routine tuberculosis control strategies.

Adult↗
PubMed2001

Rising number of tuberculosis cases among Tibetans in New York City.

Tuberculosis among Tibetans increased in New York City between 1995 and 1999. We examined characteristics of 68 Tibetan patients compared to 702 non-Tibetan patients from Nepal, India, or China, diagnosed between January 1995 and December 1999. The number of Tibetan patients increased each year after 1995 whereas non-Tibetans remained stable during the same period. Tibetans were younger (27 vs. 44 years), more likely to be infectious (63% vs. 46%), have multidrug resistance (7% vs. 2%) and shorter time to diagnosis after arrival (9 vs. 79 months, p < 0.01). For Tibetan patients, 68% of identified contacts were evaluated. The prevalence of tuberculosis infection was 65%. In contrast, among non-Tibetan patients 88.8% of contacts were evaluated and 45.2% were infected. Outreach efforts with community leaders and educational presentations at community events have been implemented in an effort to ensure continuity of care and completion of treatment.

Journal Article↗
PubMed2001

Tuberculosis treatment in nepal: a rapid assessment of government centers using different types of patient supervision.

SETTING: Urban and periurban government tuberculosis (TB) treatment clinics in Nepal. OBJECTIVE: To assess TB treatment supervision strategies and outcomes. DESIGN: Three types of treatment centers were selected according to intensity of treatment supervision: Group A-all patients supervised by directly observed therapy (DOT) at the treatment center during the intensive phase; Group B-flexible DOT where patient-nominated treatment supervisors include community or family members; Group C-drugs dispensed monthly and no supervised treatment. The cohort studied comprised all new patients starting treatment during a 5-month period in 1996 (n = 759). RESULTS: At group A treatment centers, 100% of patients had daily DOT supervised by treatment center staff during the intensive phase. At group B sites, 75% of nominated supervisors were family or community members and 13% of patients had no supervisor. At group C sites 93% of patients were unsupervised. Bacteriologically confirmed cure rates for smear-positive patients were 91% (95%CI 80.3-97.2) for A sites, 57% (95%CI 48.8-64.0) for B, and 34% (95%CI 25.1-40.4) for C. Treatment centers with the best results had good access to laboratory facilities, uninterrupted drug supply, longer clinic hours, standardized TB case management, and support from a non-governmental organization. CONCLUSION: At government facilities in Nepal, only group A treatment centers achieved World Health Organization global targets for cure. Group B treatment centers showed better outcomes than unsupervised therapy but did not achieve cure targets. Rapid low-cost assessments to collect data that are not routinely reported can improve the evaluation of program aspects such as supervision strategies.

Adolescent↗
PubMed2000

Prevalence of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in the community.

Recent reports indicate that community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are increasing and may now involve persons without risk factors predisposing for acquisition. To estimate the extent of community MRSA in New York City, the prevalence of S. aureus and MRSA nasal colonization in a well-patient population of 500 children and guardians was determined. The prevalence of S. aureus nasal carriage was 35% for children and 28% for guardians. One person with predisposing risk factors was colonized with an MRSA, which was identified as the predominant clone found in New York City hospitals. A high degree of methicillin-susceptible S. aureus strain diversity was noted, with no apparent selection for specific clonal types. Thus, MRSA colonization is not ubiquitous in persons without predisposing risk outside of the health care environment. Bacterial competition and a lack of strong selection may limit the community spread of MRSA and can account for its sporadic distribution.

Adolescent↗
PubMed2000

Resistance rather than virulence selects for the clonal spread of methicillin-resistant Staphylococcus aureus: implications for MRSA transmission.

The population structure of methicillin-resistant Staphylococcus aureus (MRSA) is predominantly clonal, which may be related to the fitness of the genetic background of the methicillin-susceptible S. aureus (MSSA) into which the mecA chromosomal resistant determinant has inserted. To test this idea, we assessed whether the genotypes of New York MRSA are present in MSSA populations by using a combination of protein A gene sequence typing (spa typing) and pulsed-field gel electrophoresis (PFGE). Although about 16% of colonizing MSSA isolated from community subjects were related to MRSA, only one of the five predominant New York MRSA clonal types was found among the MSSA isolates. Similarly, among nosocomial MSSA, only four MRSA homologues were observed, two of which may have arisen through deletion of the mec element. Thus, MRSA clonal types represent a limited spectrum of the diversity seen in community and hospital S. aureus populations. The data are best explained by antibiotic selection pressure, as opposed to increased transmissibility or virulence, being responsible for the clonal dissemination of the resistance phenotype in MRSA genetic backgrounds, an in turn, the limited spread of these strains outside of the hospital environment.

Amino Acid Sequence↗
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↗