Clinical Characteristics of Extended-spectrum β-lactamase Producing Shigella sonnei Infection Outbreaked in Chungju Area

Abstract

Background : An outbreak of extended-spectrum -lactamase (ESBL)-producing Shigella sonnei enteritis, especially in pediatric populations, was unprecedented not only in Korea, but also throughout the world in the past. This study was intended to devise a management guideline for shigellosis caused by an ESBL-producing strain based on analysis of the clinical manifestations and response to therapy.Methods : We examined 24 strains of S. sonnei isolated from stool cultures of patients with acute enteritis, between November 2004 and February 2005, for antimicrobial susceptibility and ESBL production, and we also performed DNA sequencing with PCR for the typing of ESBL genes. In addition, we retrospectively analyzed the clinical characteristics, laboratory results, and therapeutic responses to antibiotics of the 103 patients who grew S. sonnei on stool cultures.Results : All 24 isolates showed a very similar antibiotic sensitivity pattern and were ESBL gene type of CTX-M-14. The most frequent clinical symptom in the 103 patients was a fever, followed by diarrhea, abdominal pain, headache, vomiting, and nausea. Leukocytosis and CRP were positive in 53.4% and 78.6% of the patients, respectively. On stool direct smears, 11.7% showed more than 50 WBCs per HPF and 71% were positive on stool occult blood. Microbiological eradication rates were as follows: azithromycin and ciprofloxacin, 100%; imipenem-cilastatin, 68.8%; ampicillin-sulbactam, 42.9%; amoxicillin-clavulanic acid, 20%; ceftizoxime, 12.5%; cefdinir, 6.9%; and ceftriaxone and trimethoprim-sulfamethoxazole, 0%.Conclusions : We presumed that, given its cost-effectiveness and safety, azithromycin can be an attractive option for the treatment of ESBL-producing S. sonnei enteritis in pediatric populations. Although ciprofloxacin is another cost-effective agent, its use in pediatric populations is not recommended. (Korean J Lab Med 2006;26:168-73

Strategies to overcome extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases in shigellae

“…Ceftibuten, cefdinir, cefotaxime, ceftriaxone and mecillinam are active in shigellosis caused by susceptible strains [7,21,22] and so must achieve adequate penetration.…”

“…Most ESBLs in shigellae are now CTX-M types and, as shown by a Korean study, these enzymes are associated with cephalosporin failure [7]. If ESBLs or AmpC enzymes occur in strains already resistant to fluoroquinolones and cotrimoxazole, azithromycin may be the sole option for oral therapy.…”

“…associated with plasmid-mediated AmpC enzymes in Argentina [5] and Taiwan [6] or, more often, with extended-spectrum -lactamases (ESBLs), which have been reported in shigellae from East Asia [7][8][9], the Middle East [10][11][12][13] and Argentina [14]. Most ESBLs in shigellae are now CTX-M types and, as shown by a Korean study, these enzymes are associated with cephalosporin failure [7].…”

CTX-M-55-Type Extended-Spectrum β-lactamase- Producing Shigella sonnei Isolated from a Korean Patient Who Had Travelled to China

“…The spread of CTX-M type ESBL-producing Shigella species has become of concern worldwide because the increasing circulation of this resistant strain further narrows the choice of effective antibiotics. In Korea, only CTX-M-14-producing Shigella sonnei have been reported [9-11]. …”

Comparison of Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing Breakpoints for β-Lactams inEnterobacteriaceaeProducing Extended-Spectrum β-Lactamases and/or Plasmid-Mediated AmpC β-Lactamases

“…Seventy-five isolates had been previously characterized by appropriate biochemical, phenotypic, and molecular procedures to determine their types of β-lactamase production [7][8][9][10][11][12]. Six isolates including an TEM-8-producing E. coli, an SHV-2-producing K. pneumoniae, two TEM-52-producing P. mirabilis, and two CTX-M-14-producing P. mirabilis were obtained from Dr. Kyungwon Lee (Yonsei University College of Medicine, Seoul, Korea).…”