Risk factors for tuberculosis in contact investigations in Rotterdam, the Netherlands

Contact investigations around tuberculosis patients enable early detection of infection and disease, and prevention of secondary tuberculosis cases. We aim to identify risk factors for M. tuberculosis transmission to contacts of tuberculosis patients, based on unique data from routine contact investigations by the Public Health Service in Rotterdam, the Netherlands, collected between 2001 and 2006. Through logistic regression analysis, we determined the effect of various risk factors on the chance of finding a latent tuberculosis (TB) infection or overt tuberculosis case among contacts. A total of 1165 index patients with active tuberculosis were registered and at least one contact was investigated in 731, resulting in 21,540 contacts overall. Altogether, the contact investigations led to 91 cases of active tuberculosis. Of the 12,698 contacts eligible for screening by tuberculin skin test, 1091 (9%) were diagnosed with latent tuberculosis infections. Risk factors were old age of the contact, old age of the index patient, and the relationship to the index. A larger fraction of infected close contacts was strongly associated with infections among more distant contacts.

Our findings emphasize the importance of including these personal and interpersonal risk factors in decision making in contact investigations.

A systematic review of economic evaluation studies of tuberculosis control in high-income countries

Tuberculosis (TB) is a leading cause of death in developing countries and an important health threat in the industrialised world. Ideally, interventions in TB control are effective, acceptable and economically attractive. This review summarises all economic evaluation studies of TB control in high-income countries over the last 20 years. We provide indications on the relative economic attractiveness of TB interventions based on the reported conclusions. A total of 118 studies using different economic evaluation methodologies on a wide range of TB interventions are included. Most studies (70%) were from North America, and about half (47%) concerned interventions among the general population. Even though the large majority of studies (85%) aimed at preventing active TB disease, 44% of these ignored the prevention of secondary infections, thereby under- estimating the benefits of the intervention. Choosing a health care instead of a societal perspective (92% vs. 8%) further underestimated the benefits. Moreover, 74 studies (62%) disregarded discounting, and for 9 of them this led to overestimated future costs. In all, 66% of the studies reported conclusions favouring the evaluated intervention, which is modest given that a publishing bias towards favourable results is to be expected. In conclusion, we demonstrate that many studies in this review have put the evaluated TB intervention at a disadvantage by the choice of methodology, i. e., underestimating benefits and overestimating costs. This may have led to an overly conservative approach to the introduction of new interventions in TB control.

Prevalence of meticillin-resistant Staphylococcus aureus amongst professional meat handlers in the Netherlands, March-July 2008

In the Netherlands, meticillin-resistant Staphylococcus aureus (MRSA) is detected on pork and veal farms, and hence farmers working with MRSA-positive animals are at an increased risk of being colonised. Recently retail meat products have been found positive for MRSA. Therefore, we tested the prevalence of MRSA among employees who work in the cold meat processing industry and in institutional kitchens. Nasal swabs and samples from the employees' hands as well as the handled meat were tested quantitatively and qualitatively for the presence of MRSA. Typical colonies were confirmed by PCR and typed using multi-locus sequence typing and spa–typing. All samples taken from 95 employees tested negative for MRSA, but 31 carried MSSA. From meat, five of 35 samples were positive for MRSA, containing between 0.01 and more than 10 bacteria per gram. The risk for professionals of MRSA colonisation from handling raw meat was therefore low in our setting, suggesting that the general population is at an even lower risk of being infected through meat handling.