BACKGROUND: The emergence of carbapenemase-producing Enterobacteriaceae (CPE) represents a major clinical problem because these bacteria are resistant to most antibiotics. CPE remain relatively uncommon in Korea. We report the prevalence, clinical characteristics, and molecular epidemiology of CPE isolates collected from five university hospitals in Korea. METHODS: Between January and December 2015, 393 non-duplicated isolates that were nonsusceptible to ertapenem were analyzed. Production of carbapenemase, extended-spectrum β-lactamase, and AmpC β-lactamase was determined by genotypic tests. Antimicrobial susceptibility profiles were determined by using an Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC)-2-producing and oxacillinase (OXA)-232-producing Klebsiella pneumoniae isolates was determined by pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 393 isolates tested, 79 (20.1%) were CPE. Of these 79 isolates, 47 (59.5%) harbored the bla(OXA-232) gene while the remaining isolates carried genes bla(KPC-2) (n=27), bla(IMP-1) (n=4), and bla(NDM-1) (n=1). Among the 24 KPC-2 K. pneumoniae isolates from hospital B, 100% were resistant to carbapenems, 8% to colistin, and 0% to tigecycline. Among the 45 OXA-232 K. pneumoniae at hospital C, 95% were resistant to ertapenem, 68% to imipenem, 95% to meropenem, 10% to colistin, and 24% to tigecycline. PFGE analysis revealed a unique pattern for KPC-2 K. pneumoniae and identified 30 isolates belonging to the dominant pulsotypes (PT)1 and PT2 among 41 OXA-232 K. pneumoniae isolates. CONCLUSIONS: CPE strains are present in Korea, with the majority of K. pneumoniae isolates producing OXA-232 and KPC-2. The prevalence and predominant genotypes of CPE show hospital-specific differences.
Aged ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/metabolism ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Enterobacteriaceae/drug effects/*enzymology/isolation & purification ; Enterobacteriaceae Infections/diagnosis/epidemiology/*microbiology ; Female ; Genotype ; Hospitals ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Prevalence ; Republic of Korea/epidemiology ; beta-Lactamases/*genetics/metabolism

PURPOSE: Enterobacter sakazakii (E. sakazakii) infections are an important cause of life-threatening meningitis, septicemia, and necrotizing enterocolitis in infants. Dried infant formula milk is an important vehicle for E. sakazakii infection. E. sakazakii was isolated in Korea from dried infant formula milk. Although E. sakazakii infection of infants may occur in Korea, its prevalence has not yet been documented. Therefore, we determined the prevalence of E. sakazakii and documented symptoms. MATERIALS AND METHODS: Between March and October 2006, 1,146 stool samples were collected from patients at Uijeongbu St. Mary's Hospital. Each fecal swab was dissolved in 10mL of buffered peptone solution, and enriched culture was streaked onto Druggan-Forsythe-Iversen (DFI) agar. Presumptive E. sakazakii colonies that exhibited a blue-green color during culture on DFI medium were selected. The identity of colonies that developed yellow pigment during culture on TSA was determined using the Vitek system and PCR. RESULTS: We isolated 4 E. sakazakii strains whose 16S rRNA sequence alignments had a similarity of 99% with those of 3 E. sakazakii ATCC strains. CONCLUSION: This is the first report on isolation of E. sakazakii from stool samples and to document the symptoms of Korean patients.
Adolescent ; Adult ; Aged ; Base Sequence ; Child ; Child, Preschool ; Drug Resistance, Multiple, Bacterial ; *Enterobacter sakazakii/drug effects/genetics/isolation & purification ; Enterobacteriaceae Infections/diagnosis/*epidemiology/microbiology ; Feces/microbiology ; Female ; Humans ; Infant ; Infant, Newborn ; Korea/epidemiology ; Male ; Middle Aged ; Molecular Sequence Data ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Homology, Nucleic Acid ; Young Adult