Ecolab, Inc., announced Thursday that it has acquired Brazil-based pest elimination company InsetCenter-the company's third buy in a week.

The St. Paul-based company on December 1 closed on a deal to buy Naperville, Illinois-based water treatment provider Nalco Holding Company for $8.3 billion. Just four days later, it announced that it acquired Esoform, an Italian company that makes products used in personal care and for fighting infections.

Ecolab did not disclose financial terms of its acquisition of InsetCenter, but it said that the company has approximately $6 million in annual sales.

Ecolab, which already offers pest elimination services in Brazil, said the acquisition will substantially increase its service capacity and scale in the country.

Ecolab is among Minnesota's 15-largest public companies based on revenue, which totaled $6.1 billion in 2010. It offers cleaning, sanitizing, food safety, pest control, and infection prevention products and services to foodservice, food and beverage processing, health care, and hospitality markets.