Detection of Staphylococcus aureus including MRSA on environmental surfaces in a jail setting.

We examined jail environmental surfaces to explore whether they might serve as reservoirs of viable methicillin-resistant Staphylococcus aureus (MRSA). We swabbed 132 surfaces, inoculated primary and secondary mannitol salts and oxacillin-resistant screening agar, and used API tests to identify S. aureus and E-tests to determine methicillin/oxacillin resistance. We recovered S. aureus from 10 (7.6%) surfaces; eight (6.1%) isolates were MRSA. We ran pulsed-field gel electrophoresis on six resistant isolates and observed three patterns, one of which was identical to that identified in a previous study of inmates' nasal specimens. Finding MRSA-contaminated surfaces on a variety of environmental surfaces in the absence of an overt outbreak emphasizes that correctional facilities should have protocols for environmental cleaning as a component of MRSA prevention.

Transmission of drug-resistant tuberculosis in Texas and Mexico.

To examine the transmission of drug-resistant (DR) tuberculosis between Texas and Mexico, Mycobacterium tuberculosis isolates resistant to one or more of the first-line antimycobacterial drugs were obtained from 606 patients who resided in Texas and 313 patients who resided in Mexico, primarily within the state of Tamaulipas. The isolates were genotyped by IS6110-based restriction fragment length polymorphism (RFLP) analysis and spoligotyping. Of the 919 isolates genotyped, 413 (45%) grouped into 105 clusters containing 2 or more isolates with identical genotypes. In addition to having identical genotypes, identical drug resistance patterns were identified in 250 isolates in 78 clusters (DR clusters). Twenty DR clusters, containing isolates from 32% of the total number of patients infected with DR strains, were geographically distributed across Mexico and Texas. Within this population of 919 patients infected with DR isolates, the probability of being in a DR cluster was the same for residents of Mexico and Texas. In Texas, the significant independent predictors of clustering within DR clusters as opposed to genotype clusters were found to be race, age, country of birth, human immunodeficiency virus (HIV) infection status, and resistance to more than one drug. Specifically, isolates from African Americans, individuals under age 65, individuals born in the United States, and HIV-positive individuals were each more likely to be associated with a DR cluster. By contrast, no significant independent predictors of clustering in a DR cluster were identified in Mexico. Although some DR M. tuberculosis strains are geographically restricted, this study suggests that a number of strains are transmitted between Mexico and the United States.