Tuberculosis Outbreak Investigations in the United States, 2002–2008

Mitruka, Kiren; Oeltmann, John E.; Ijaz, Kashef; Haddad, Maryam B.

doi:10.3201/eid1703.101550

Cited by 47 publications

(58 citation statements)

References 25 publications

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“…Each of the sublineages had specific mutations that, based on their SIFT values, suggested an impact on gene function. The strains from sublineage RD207 had a mutation in Rv0989c (grcC2), a diphosphate synthase required for cell wall biosynthesis (27). These strains also had a mutation in the gene Rv2959c, encoding a methyltransferase involved in the biosynthesis of phenolglycolipid, which is considered a virulence factor (39).…”

Section: Discussionmentioning

confidence: 99%

“…Although some of these mutations may explain the pathological and immunological differences observed, there are a multitude of factors that can influence the transmission and pathogenic capabilities of a given isolate, such as host and environmental factors (5,20,27,38), HIV coinfection (42), and the concentration of organisms in environmental air (17). Until recently, the only bacterial factor considered was the presence of drug resistance; some studies have suggested that M. tuberculosis resistant to isoniazid is less transmissible (52) and less pathogenic than fully susceptible organisms (7,11), although an earlier study in our laboratory (33) investigating the virulence of multidrug-resistant isolates did not show much evidence of loss of virulence of these strains.…”

Section: Figmentioning

confidence: 99%

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Beijing Sublineages of Mycobacterium tuberculosis Differ in Pathogenicity in the Guinea Pig

Kato‐Maeda

Shanley

Ackart

et al. 2012

Clin. Vaccine Immunol.

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ABSTRACTThe Beijing family ofMycobacterium tuberculosisstrains is part of lineage 2 (also known as the East Asian lineage). In clinical studies, we have observed that isolates from the sublineage RD207 of lineage 2 were more readily transmitted among humans. To investigate the basis for this difference, we tested representative strains with the characteristic Beijing spoligotype from four of the five sublineages of lineage 2 in the guinea pig model and subjected these strains to comparative whole-genome sequencing. The results of these studies showed that all of the clinical strains were capable of growing and causing lung pathology in guinea pigs after low-dose aerosol exposure. Differences between the abilities of the four sublineages to grow in the lungs of these animals were not overt, but members of RD207 were significantly more pathogenic, resulting in severe lung damage. The RD207 strains also induced much higher levels of markers associated with regulatory T cells and showed a significant loss of activated T cells in the lungs over the course of the infections. Whole-genome sequencing of the strains revealed mutations specific for RD207 which may explain this difference. Based on these data, we hypothesize that the sublineages ofM. tuberculosisare associated with distinct pathological and clinical phenotypes and that these differences influence the transmissibility of particularM. tuberculosisstrains in human populations.

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Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Beijing Sublineages of Mycobacterium tuberculosis Differ in Pathogenicity in the Guinea Pig

Kato‐Maeda

Shanley

Ackart

et al. 2012

Clin. Vaccine Immunol.

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“…We believe this is because foreign-born children with TB who are living in the United States most likely acquired their infection before immigration to the United States, and if the source of their infection is still overseas it would not be captured in the NTSS. While index cases may not always be source cases, our findings are similar to those from studies that assessed risk factors for genotype clustering, 6 recent transmission 7 and involvement in outbreaks, 8 reinforcing the notion that index cases characterized by these risk factors may often be the source case for future cases. We found only one study that assessed characteristics associated with the generation of secondary cases using epidemiologic but not genotyping data.…”

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confidence: 99%

Using tuberculosis patient characteristics to predict future cases with matching genotype results

Oeltmann

Click

Moonan

2014

public health action

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Setting: United States. Background: It is unknown whether tuberculosis (TB) case or patient characteristics can predict the likelihood of future related TB cases. Objective: To estimate the likelihood for future related cases, i.e., cases with matching TB genotypes within the same county diagnosed within the 2 years following the year of reporting of each included case. Design: We considered all TB cases with genotyping results reported in the United States during [2004][2005][2006][2007][2008][2009][2010]. Predictive scores were calculated based on patient characteristics by dividing the number of patients who were not the last case in a county-level TB genotype cluster by the total number of patients. Results: Overall, there was a 30.8% chance that a future related case would be detected during the 2 years following the report year of any given case. Future related cases were detected in 34.7% of instances following the diagnosis of smear-positive cases, 51.9% of instances following the diagnosis of a homeless patient and 45.2% of instances following the diagnosis of a patient who reported substance abuse. Predictive scores ranged by race (White 13.9%, Native Hawaiian 43.8%) and age group (65 years 13.1%, 0-4 years 43%), and were higher for US-born patients. Conclusions: Behavioral and sociodemographic factors can help predict the likelihood of future related cases and can be used to prioritize contact investigations. Public Health Action Predicting future related TB cases 48lessness, incarceration at the time of diagnosis, sputum smear status, site of disease and human immunodeficiency virus (HIV) status. In the NTSS, excess alcohol use, injection drug use, and non-injection drug use are defined as positive if reported within the year before TB diagnosis. We defined substance abuse as having any one of these three behaviors reported. We used multivariate logistic regression to assess the association between being an index case, relative to unique cases (dependent variable), and the abovementioned independent factors. A significance level of 0.01 was used for all statistical tests. Predictive scores of patient characteristicsTo estimate the ability with which individual patient characteristics can predict one or more future related cases, we calculated predictive scores for patient and clinical characteristics for both US-born and foreign-born patients. For any given case, a future related case was a case with matching genotyping results diagnosed in the same county during the 2 years following the report year of each included case. All cases in a cluster were categorized as either the last case diagnosed in a cluster or not the last case diagnosed in a cluster. . Therefore, for each case included, there were at least 2 years of follow-up time during which another case with matching genotype results could have been diagnosed within the same county. This length of time is referred to as the follow-up period. A predictive score was calculated for each sociodemographic, behavioral and clinical characteristic. Pr...

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“…5,24 The index patient's prolonged infectious period, resulting primarily from treatment nonadherence but also a delay in seeking medical care, was the main factor that fueled this outbreak. Delayed diagnosis is a wellknown risk factor for TB transmission, 14,25 and it has previously contributed to at least two known TB outbreaks involving undocumented people. 26,27 Undocumented foreign-born people are more likely than documented people to delay seeking care for symptoms, 28 thereby prolonging the infectious period when TB can be transmitted to others.…”

Section: Discussionmentioning

confidence: 99%

“…13 To prevent further cases, exposed people with pending or incomplete TB evaluation and LTBI treatment were classified into high, medium, and low priority for follow-up based on the presence of TB risk factors, extent of exposure (i.e., intensity, duration, and frequency), and risk of developing TB disease. 13,14 Additional contacts identified during the outbreak investigation interviews and chart reviews were added to the database and prioritized for evaluation.…”

Section: Outbreak Investigationmentioning

confidence: 99%

A Tuberculosis Outbreak Fueled by Cross-Border Travel and Illicit Substances: Nevada and Arizona

et al. 2014

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Objectives. From May 2006 to August 2008, the Southern Nevada Health District identified eight tuberculosis (TB) cases in six adults and two children in a Hispanic community. We conducted an outbreak investigation to determine the extent of TB transmission and prevent additional cases.Methods. We investigated TB cases in Nevada and Arizona with the outbreak genotype or cases with suspected epidemiologic links to this cluster but without genotyping data. We reviewed medical records and interviewed patients and contacts. Subsequently, genotype surveillance was conducted for approximately four years to monitor additional outbreak-related cases.Results. Eight outbreak cases were identified among six adults and two children. All patients were Hispanic and five were U.S.-born. The index patient was diagnosed while detained in Immigration and Customs Enforcement custody but deported before treatment completion. He was lost to follow-up for two years, during which time he served as the source for six secondary TB cases, including his own child. Along with the index patient, five patients reportedly engaged in the sale or use of methamphetamine. Follow-up surveillance in the two states identified eight additional cases with the outbreak genotype; three had epidemiologic links to the index case.Conclusions. We found that incomplete TB treatment led to extensive TB transmission. We recommend thorough discharge planning and active measures to ensure continuity of care and TB treatment completion for people in custody at higher risk for loss to follow-up, which likely includes those engaged in the sale or use of illicit substances.

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Tuberculosis Outbreak Investigations in the United States, 2002–2008

Cited by 47 publications

References 25 publications

Beijing Sublineages of Mycobacterium tuberculosis Differ in Pathogenicity in the Guinea Pig

Beijing Sublineages of Mycobacterium tuberculosis Differ in Pathogenicity in the Guinea Pig

Using tuberculosis patient characteristics to predict future cases with matching genotype results

A Tuberculosis Outbreak Fueled by Cross-Border Travel and Illicit Substances: Nevada and Arizona

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