Study of developed resistance due to antibiotic treatment of coagulase-negative Staphylococci.

Coagulase-negative Staphylococci (CoNS) are a major cause of postoperative infections. These infections are often associated with foreign material implants and/or a compromised immune system in the patient. Multiresistant strains are increasingly common in the hospital environment and there is concern that the infections will become difficult or impossible to treat. This report is based on a study of 75 patients, with postoperative infections caused by CoNS after thoracic surgery. All patients were treated with surgical revision and antibiotic therapy. One or more bacterial cultures were made in each case, and the resistance pattern of the CoNS found was determined. The goal of the study was to evaluate possible relationships between antibiotic therapy and the appearance of resistance to antibiotics in CoNS found. To describe this relationship, three models were constructed and analyzed by multiple logistic regression. The results indicate an increased resistance to beta-lactam antibiotics and clindamycin after the use of cephalosporins. Also, the use of vancomycin or vancomycin in combination with rifampicin or fusidic acid increases the risk for development of resistance to beta-lactam antibiotics, ciprofloxacin, fusidic acid, clindamycin, netilmycin, and rifampicin. The hypothesis that a combination of antibiotics will curtail the development of resistance was not supported in this study.