Clinical and microbiological features of Providencia bacteremia: experience at a tertiary care hospital

BACKGROUND/AIMS: Providencia species frequently colonize urinary catheters and cause urinary tract infections (UTIs); however, bacteremia is uncommon and not well understood. We investigated the clinical features of Providencia bacteremia and the antibiotic susceptibility of Providencia species. METHODS: We identified cases of Providencia bacteremia from May 2001 to April 2013 at a tertiary care hospital. The medical records of pertinent patients were reviewed. RESULTS: Fourteen cases of Providencia bacteremia occurred; the incidence rate was 0.41 per 10,000 admissions. The median age of the patients was 64.5 years. Eleven cases (78.6%) were nosocomial infections and nine cases (64.3%) were polymicrobial bacteremia. The most common underlying conditions were cerebrovascular/neurologic disease (n = 10) and an indwelling urinary catheter (n = 10, 71.4%). A UTI was the most common source of bacteremia (n = 5, 35.7%). The overall mortality rate was 29% (n = 4); in each case, death occurred within 4 days of the onset of bacteremia. Primary bacteremia was more fatal than other types of bacteremia (mortality rate, 75% [3/4] vs. 10% [1/10], p = 0.041). The underlying disease severity, Acute Physiologic and Chronic Health Evaluation II scores, and Pitt bacteremia scores were significantly higher in nonsurvivors (p = 0.016, p =0.004, and p = 0.002, respectively). Susceptibility to cefepime, imipenem, and piperacillin/tazobactam was noted in 100%, 86%, and 86% of the isolates, respectively. CONCLUSIONS: Providencia bacteremia occurred frequently in elderly patients with cerebrovascular or neurologic disease. Although Providencia bacteremia is uncommon, it can be rapidly fatal and polymicrobial. These characteristics suggest that the selection of appropriate antibiotic therapy could be complicated in Providencia bacteremia.

Macrolide Resistance in beta-Hemolytic Streptococci: Changes after the Implementation of the Separation of Prescribing and Dispensing of Medications Policy in Korea

This study evaluated the antimicrobial susceptibilities and macrolide resistance mechanisms of beta-hemolytic streptococci (BHS), and an additional objective was to assess the effects of 'the separation of prescribing and dispensing (SPD) of medications' on bacterial resistance rate and distribution of phenotypes and genotypes of erythromycin-resistant BHS by comparing the antimicrobial susceptibility data before (1990- 2000) and after the implementation of SPD at one tertiary care hospital in South Korea. Between the period of January 2001 and December 2002, the minimal inhibitory concentrations of six antimicrobials were determined for 249 clinical isolates of BHS. Resistance mechanisms of erythromycin-resistant (intermediate and resistant) isolates were studied by using the double disk test and PCR. Overall, the resistance rates to tetracycline, erythromycin, and clindamycin were 75.5%, 32.9%, and 32.5%, respectively. Sixty-seven (81.7%) of 82 erythromycin- resistant isolates expressed constitutive resistance to macrolide- lincosamide-streptogramin B antibiotics (a constitutive MLSB phenotype) ; 11 isolates (13.4%) expressed an M phenotype; and four isolates (4.9%) had an inducible MLSB resistance phenotype. erm (A) was found in isolates with constitutive/ inducible MLSB phenotypes, erm (B) with the constitutive/ inducible MLSB phenotype, and mef (A) with the M phenotype. We found that resistance rates to erythromycin and clindamycin among S. agalactiae, S. pyogenes, and group C streptococci isolates were still high after the implementation of the SPD policy in Korea, and that the constitutive MLSB resistance phenotype was dominant among erythromycin- resistant BHS in this Korean hospital.