Sharps or needlestick injury carries with it, in some circumstances, a predictable risk of bloodborne virus infection. The statistics, from which risk can be calculated, are well known and relate to the “average” used hollow bore needle used in clinical practise, and sharps injuries occurring during or soon after use.

There are many additional variables including the time between use of the needle and its involvement in a sharps injury, the amount of blood that it contains, the bore of the needle and depth of injury, the immune status of the victim, post-injury care, the virus concentrations in the blood if any, the time interval between injury and post-exposure prophylaxis if this is indicated, and probably other factors of which we know very little.

But we must not close our minds to the possibility that sharps-related infections are limited to HIV, Hepatitis B and Hepatitis C infections. Other infections can and do occur. In fact, the diversity of infections that have been reported is substantial though the list is bolstered by many individual laboratory acquired infections that arise as, one must hope, a one-off occurrence.

Most of the odds-and-sods reports of sharps-related infections are rare indeed, and unlikely to concern those involved in wastes management since the organisms involved are uncommon and few laboratories deal with them; most will loose viability quickly once outside the body or a laboratory culture.

Another recent report does however give cause for concern.

Belchior I, Seabra B, Duarte R. Primary inoculation skin tuberculosis by accidental needle stick. BMJ Case Rep. 2011 Jun 15;2011. pii: bcr1120103496. doi: 10.1136/bcr.11.2010.3496.

This reports the case of a 42-year-old laboratory worker who presented with a left index finger skin lesion after an accidental needlestick while handling samples of a cultural exam of Mycobacterium tuberculosis, the causative organism of TB. Surgical excision was performed and pathology analysis revealed a dermic chronic inflammatory process with no granulomas. Later, a non-painful lymphadenopathy appeared in the left axilla as well as brownish indurated skin lesions in the lower limbs consistent with erythema nodosum. Fine needle aspiration biopsy of the lymph node revealed epithelioid granulomas, Langhans’ multinucleated giant cells and the presence of acid-fast bacilli. Standard tuberculosis treatment resulted in regression of lesions and no relapses occurred in the 2-year follow-up period.

Obviously, a nasty local and subsequent systemic infection causing severe problems as a consequence. More worrying is the longevity of M tuberculosis in a dry and room temperature state that would retain viability for days, weeks and months after discard. Still unlikely, since it is not common to use hypodermic needles in laboratory studies of TB, but the risk exists and does not diminish as sharps enter the disposal chain.