UK prisoners are significantly more likely to have drug resistant TB than other people with the disease, suggests research published ahead of print in the Journal of Epidemiology and Community Health.
And one in four of TB cases fall through the healthcare net once they leave prison.
The researchers profiled the features of newly diagnosed adult cases reported to the national TB surveillance service for England and Wales between 2004 and 2007.
During this period, 29,340 cases of TB disease were reported, of which 205 were prison inmates.
An overseas birth is a known risk factor for TB. But prisoners with TB were almost twice as likely to be born in the UK rather than overseas - 47% vs 25% - compared with other TB patients.
And they were nine times more likely to be of black Caribbean ethnicity - 18% vs 2%. Three out of four also had TB disease in their lungs, compared with just over half (56%) of other TB patients.
Prisoners with TB in their lungs were significantly more likely to be infectious - 69% vs 57%.
Rates of drug resistant disease were also extremely high among prisoners. More than one in three (35%) had a strain of TB that was resistant to the drug normally prescribed as treatment - isoniazid.
This means that a minimum 4% of all drug resistant cases occurred in prisoners during this period, say the researchers, and among drug resistant cases born in the UK, 11% were known to be prisoners (25 out of 228 cases).
Prisoners also fare worse than other TB patients, the study shows: fewer than half completed their treatment within a year - 48% vs 80%.
And one in four of those still receiving treatment when they left prison fell through the healthcare net and did not get further check-ups. More than half of them (55%) had the drug resistant form of TB.
Compared with other TB patients, fewer prisoners died before they completed their treatment, but their average age at death was significantly lower - 48 compared with 70.
The authors warn that their figures are likely to underestimate the true prevalence of TB disease among UK prisoners as the study did not include former prisoners or those with latent/unreported infection.
"High rates of [TB], especially drug-resistant tuberculosis, among prisoners with low levels of successful treatment mean prisoners present a particular challenge for tuberculosis control," they say.
The authors acknowledge that moves are afoot to strengthen control of the disease in UK prisons, but they point out that prisoners are particularly vulnerable as their health is often already compromised by drug and alcohol problems, homelessness, and HIV infection.
Provided by British Medical Journal