Multiple strains of Mycobacterium avium subspecies hominissuis infections associated with aborted fetuses and wasting in pigs

A herd of pigs being reared for breeding and fattening, in which there had been incidences of abortion and wasting, reduced growth rates and an increase in mortality for the past year, were tested for Mycobacterium infection by pathological examinations, skin test, serology and Mycobacterium culture. In one placenta, and also in the lung tissues of fetuses, Ziehl-Neelsen staining revealed acid-fast bacilli in combination with infiltrations of neutrophils, macrophages and multinucleated giant cells. Acid-fast bacilli were also found in the mesenteric lymph nodes, liver and/or spleen and jejunum of pigs with wasting and in slaughtered animals. The specimen cultures were identified as Mycobacterium avium subspecies hominissuis using IS1245-specific PCR and IS1245 restriction fragment length polymorphism (RFLP). IS1245 RFLP revealed that the herd was infected with multiple M avium subspecies hominissuis strains belonging to at least two different clades. It is suggested that this infection may have played a more important role in the economic losses of the pig farm than had been assumed previously.

Public health impact of isoniazid-resistant Mycobacterium tuberculosis strains with a mutation at amino-acid position 315 of katG: a decade of experience in The Netherlands

A previous limited study demonstrated that Mycobacterium tuberculosis isolates with a mutation at amino-acid position 315 of katG (Delta315) exhibited high-level resistance to isoniazid and were more frequently resistant to streptomycin. In the present study, isoniazid-resistant M. tuberculosis isolates from 8,332 patients in The Netherlands (1993-2002) were screened for the Delta315 mutation. Isoniazid resistance was found in 592 (7%) isolates, of which 323 (55%) carried Delta315. IS6110 restriction fragment length polymorphism analysis showed that Delta315 isolates occurred in clusters, suggesting recent transmission, at the same frequency as isoniazid-susceptible isolates. In contrast, other isoniazid-resistant isolates clustered significantly less frequently. Delta315 isolates were high-level isoniazid-resistant, streptomycin-resistant and multidrug-resistant significantly more often, and may have a greater impact on public health, than other isoniazid-resistant isolates.