Mycobacterium tuberculosisCluster with Developing Drug Resistance, New York, New York, USA, 2003–2009

Abstract

In 2004, identification of patients infected with the same Mycobacterium tuberculosis strain in New York, New York, USA, resulted in an outbreak investigation. The investigation involved data collection and analysis, establishing links between patients, and forming transmission hypotheses. Fifty-four geographically clustered cases were identified during 2003–2009. Initially, the M. tuberculosis strain was drug susceptible. However, in 2006, isoniazid resistance emerged, resulting in isoniazid-resistant M. tuberculosis among 17 (31%) patients. Compared with patients with drug-susceptible M. tuberculosis, a greater proportion of patients with isoniazid-resistant M. tuberculosis were US born and had a history of illegal drug use. No patients named one another as contacts. We used patient photographs to identify links between patients. Three links were associated with drug use among patients infected with isoniazid-resistant M. tuberculosis. The photographic method would have been more successful if used earlier in the investigation. Name-based contact investigation might not identify all contacts, particularly when illegal drug use is involved.

Isolation of Mycobacterium tuberculosis Strains with a Silent Mutation in rpoB Leading to Potential Misassignment of Resistance Category

“…The hypothesis of a common ancestor in our study allows for a certain degree of microevolution, probably during transmission from one to another of the 12 hosts over a 6-year period. Partial modification of the genotyping patterns during transmission chains has been reported (1,6,9,12,14), and the same may have occurred in our cases. Nevertheless, we recognize that the heterogeneity observed was higher than expected.…”

Epidemiologic Correlates of Pyrazinamide-Resistant Mycobacterium tuberculosis in New York City

“…in a number of historic NYC drug-resistant outbreak strains (28,37), e.g., strain C (S00030) (38), strain H (S00009), strain BW (S00241) (39), and strain P (S00086) (40,41). The sequence-based confirmation of MDR genotypic clusters strongly suggests primary transmission and shows evidence that these historic strains were continuing to circulate and reactivate within NYC during the study period.…”

Characterization of Microevolution Events in Mycobacterium tuberculosis Strains Involved in Recent Transmission Clusters

“…The extensive application of IS6110 RFLP as a genotyping tool has revealed the existence of clonal variants from a common ancestor resulting from microevolution phenomena within individuals (1,6,12,13,34,37). RFLP-defined clonal variants have also appeared in transmission chains or in outbreaks involving susceptible or resistant strains (2,13,26,28,36,45). The existence of microevolution from an initial strain due to sequential host-to-host infection led to the proposal that if only identical genotypes are considered to define clusters, the percentage of recent transmission in a population is underestimated because epidemiological links are also found between cases infected by strains with RFLP patterns showing a certain degree of variation (7,17,45).…”