Infect Chemother.  2019 Mar;51(1):1-9. 10.3947/ic.2019.51.1.1.

Clinical Characteristics and Antimicrobial Susceptibility Trends in Citrobacter Bacteremia: An 11-Year Single-Center Experience

• Lee R
• Choi SM
• Jo SJ
• Lee J
• Cho SY
• Kim SH
• Lee DG
• Jeong HS

• KMID: 2442216
• DOI: http://doi.org/10.3947/ic.2019.51.1.1

Abstract

BACKGROUND
Recently, Citrobacter freundii bacteremia outbreak in a neonatal intensive care unit has attracted public attention in Korea. However, Citrobacter bacteremia is uncommon and usually occurs in patients with underlying diseases such as malignancy and hepatobiliary diseases. Increase in resistance and emerging of multidrug resistance among Citrobacter species have gradually been reported. The aim of this study was to investigate the clinical characteristics and outcome of C. freundii and non-freundii bacteremia and antimicrobial susceptibility trends.
MATERIALS AND METHODS
We reviewed the medical records of patients with Citrobacter bacteremia at St. Mary's Hospital, from 2007 to 2017.
RESULTS
A total of 43 patients with a median age of 72 (24-93) years was identified and 90.7% of them had comorbidities. Twenty-nine (67.4%) patients had C. freundii bacteremia while 14 had non-freundii bacteremia (six of C. braakii, five of C. koseri, two of C. amalonaticus and one of C. youngae). A total of 26 (51.2%) patients had community-acquired infection and intra-abdominal infection including hepatobiliary tract was the most common portal of entry (24/43, 55.8%). Moreover, hepatobiliary tract was the leading primary site of nosocomial infection (9/17, 52.9%). Polymicrobial bacteremia was observed in 21 (48.8%) patients. The percentages of Citrobacter species susceptible to ampicillin, amikacin, aztreonam, cefazolin, cefoxitin, cefotaxime, cefepime, piperacillin-tazobactam, ciprofloxacin, and imipenem were 9.5%, 97.6%, 73.8%, 9.5%, 14.3%, 71.4%, 92.9%, 83.3%, 83.3% and 100%, respectively. The resistance rate did not increase during the study period. Of 39 patients treated with antibiotics, 36 (92.3%) received appropriate empirical antibiotics. Overall mortality was 18.6%. High Charlson comorbidity index and Pitt bacteremia score were significant risk factors for death in univariate analysis and showed trends in the multivariate analysis. No significant difference in clinical features and antimicrobial susceptibility rate was observed between C. freundii and non-freundii bacteremia.
CONCLUSION
Citrobacter bacteremia was predominant in the elderly with comorbidities, while no pediatric case was observed. Hepatobiliary tract is the leading primary focus of bacteremia both in community-acquired and nosocomial infection. The rate of susceptibility to antibiotics has not changed in the last 11 years.

Keyword

Bacteremia; Citrobacter freundii; Drug resistance; Prognosis

MeSH Terms

Aged
Amikacin
Ampicillin
Anti-Bacterial Agents
Aztreonam
Bacteremia*
Cefazolin
Cefotaxime
Cefoxitin
Ciprofloxacin
Citrobacter freundii
Citrobacter*
Community-Acquired Infections
Comorbidity
Cross Infection
Drug Resistance
Drug Resistance, Multiple
Humans
Imipenem
Infant, Newborn
Intensive Care, Neonatal
Intraabdominal Infections
Korea
Medical Records
Mortality
Multivariate Analysis
Prognosis
Risk Factors
Amikacin
Ampicillin
Anti-Bacterial Agents
Aztreonam
Cefazolin
Cefotaxime
Cefoxitin
Ciprofloxacin
Imipenem

Figure

• 

  Figure 1 Annual incidence of Citrobacter bacteremia from 2006 to 2017.

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