Extraintestinal focal infections in adults with Salmonella enterica serotype Choleraesuis bacteremia

Background and Purpose: Salmonella enterica serotype Choleraesuis, which is associated with severe human infections and multidrug resistance, poses a serious problem in Taiwan. The aim of the study was to investigate the epidemiology and clinical features of S. Choleraesuis bacteremia. Methods: Medical records and antimicrobial susceptibility of blood isolates were investigated for 43 adults (≥18 years old) with S, Choleraesuis bacteremia from 1999 to 2005. Results: The proportion of S. Choleraesuis in non-typhoidal Salmonella bacteremia increased in the latter three years (2003-2005). The elderly with aged-related disorders, and younger patients receiving immunosuppressive therapy for their underlying diseases were two high-risk groups. Twenty cases (47%) had extraintestinal focal infections, including 10 cases of mycotic aneurysm, six of osteomyelitis, and 4 pleuropulmonary infections. Univariate analysis revealed that age ≥50 years was associated with occurrence of endovascular infection (p=0.008), while immunosuppressive therapy was negatively associated with endovascular infection (0=0.043). Significant resistance to first-line antimicrobial agents (i.e., ampicillin, trimethoprim-sulfamethoxazole or chloramphenicol) was noted. All strains were resistant to nalidixic acid, and 56% were resistant to ciprofloxacin. Few (<5%) isolates were resistant to ceftriaxone, and all were susceptible to cefepime, aztreonam, imipenem, meropenem and ertapenem. Multivariate analysis showed that shock (odds ratio [OR], 20.6; 95% confidence interval [CI], 1.8-239.4; p=0.016) and apyrexia (OR, 36.2; 95% CI, 3.7-358.2; p=0.002) were independent risk factors for mortality. Conclusion: S. Choleraesuis bacteremia was usually complicated with extraintestinal focal infections in the elderly. With a high level of resistance among S. Choleraesuis, fluoroquinolones should be avoided for critically ill patients with suspected Salmonella bacteremia.