With the abuse of antimicrobial agents in developing countries, increasing number of carbapenem-resistant Enterobacteriaceae (CRE) attracted considerable public concern. A retrospective study was conducted based on 242 CRE strains from a tertiary hospital in Hangzhou, China to investigate prevalence and drug resistance characteristics of CRE in southeast China. Bacterial species were identified. Antimicrobial susceptibility was examined by broth microdilution method or epsilometer test. Resistant β-lactamase genes were identified by polymerase chain reaction and sequencing. Genotypes were investigated by phylogenetic analysis. Klebsiella pneumoniae and Escherichia coli were the most prevalent types of species, with occurrence in 71.9% and 21.9% of the strains, respectively. All strains exhibited high resistance (> 70%) against β-lactam antibiotics, ciprofloxacin, trimethoprim-sulfamethoxazole, and nitrofurantoin but exhibited low resistance against tigecycline (0.8%) and minocycline (8.3%). A total of 123 strains harbored more than two kinds of β-lactamase genes. bla, bla, bla, and bla were the predominant genotypes, with detection rates of 60.3%, 61.6%, 43.4%, and 16.5%, respectively, and were highly identical with reference sequences in different countries, indicating potential horizontal dissemination. IMP-4 was the most frequent class B metallo-lactamases in this study. In conclusion, continuous surveillance and effective prevention should be emphasized to reduce spread of CRE.
Anti-Bacterial Agents ; therapeutic use ; Carbapenem-Resistant Enterobacteriaceae ; drug effects ; enzymology ; genetics ; China ; epidemiology ; Enterobacteriaceae Infections ; epidemiology ; microbiology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Phylogeny ; Prevalence ; Retrospective Studies ; beta-Lactam Resistance ; beta-Lactamases ; genetics

OBJECTIVETo study the risk factors of infection of extended-spectrum beta-lactamases (ESBL)-producing strains and drug resistance of Enterobacteriaceae that infected burn patients.

METHODSA retrospective study was performed on clinical information of 92 patients with Enterobacteriaceae infection in our burn unit from January 2001 to December 2008. The distribution and drug resistance of Enterobacteriaceae, and the detection rate, drug resistance of ESBL-producing strains, and its risk factors of nosocomial infection were analyzed. Data were processed with Chi-square test.

RESULTSOne hundred and nine strains of Enterobacteriaceae were isolated, with 38 (34.9%) strains of Enterobacter cloacae, 25 (22.9%) strains of Escherichia coli, 22 (20.2%) strains of Klebsiella pneumoniae, 13 (11.9%) strains of Proteus mirabilis, and 11 (10.1%) other strains of Enterobacteriaceae. Enterobacteriaceae were moderately or highly resistant to antibiotics except imipenem, resistance rate of which was less than 8.0%. ESBL-producing strains accounted for 44.0% in Escherichia coli, and 77.3% in Klebsiella pneumoniae. Drug-resistance rate of ESBL-producing strains to antibiotics was obviously higher than that of non ESBL-producing strains. Length of hospital stay longer than 20 days, and use of the third-generation cephalosporin longer than 5 days, quinolone antibiotics longer than 7 days, and topical antibiotics longer than 5 days were the risk factors of nosocomial infection caused by ESBL-producing strains, comparing with non ESBL-producing strains, the difference was statistically significant (with chi2 value respectively 5.491, 4.441, 15.186, 4.938, P values all below 0.05).

CONCLUSIONSEnterobacteriaceae strains in burn unit of our hospital are highly drug resistant, with high lactamase-producing rates, calling for intense monitor to control the risk factors that predispose the infection of ESBL-producing strains in order to lower the infection rate.

Adolescent ; Adult ; Burn Units ; Child ; Drug Resistance, Bacterial ; Enterobacteriaceae ; drug effects ; Enterobacteriaceae Infections ; epidemiology ; microbiology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Retrospective Studies ; Risk Factors ; Young Adult ; beta-Lactam Resistance

BACKGROUND: We investigated the rates of fecal transmission of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and carbapenem-resistant Enterobacteriaceae (CRE) among patients admitted to intensive care units (ICUs). METHODS: From June to August 2012, rectal cultures were acquired from all patients at ICU admission. For patients not carrying ESBL-E or CRE at admission, follow-up cultures were performed to detect acquisition. A chromogenic assay was used to screen for ESBL-E and CRE. Bacterial species identification and antibiotic susceptibility tests were performed using the Vitek 2 system (bioMerieux, France). ESBL genotypes were determined by PCR, and clonal relatedness of the isolates was assessed by pulsed-field gel electrophoresis. RESULTS: Out of 347 ICU admissions, 98 patients were found to be carriers of ESBL-E (28.2%, 98/347). Follow-up cultures were acquired from 91 of the patients who tested negative for ESBL-E at admission; the acquisition rate in this group was 12.1% (11/91), although none was a nosocomial transmission. For CRE, the prevalence of fecal carriage was 0.3% (1/347), and the acquisition rate was 2.9% (4/140). None of the CRE isolates were carbapenemase-producers. CONCLUSIONS: The high prevalence of ESBL-E carriage on admission (28.2%), coupled with rare nosocomial transmission and the very low carriage rate of CRE (0.3%), challenge the routine use of active surveillance in non-epidemic settings. Nevertheless, passive surveillance measures, such as rapid and accurate screening of clinical specimens, will be critical for controlling the spread of CRE.
Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*metabolism ; Carbapenems/*pharmacology ; Carrier State/epidemiology ; Cross Infection/epidemiology/*transmission ; DNA, Bacterial/analysis ; Drug Resistance, Bacterial/drug effects ; Electrophoresis, Gel, Pulsed-Field ; Enterobacteriaceae/enzymology/genetics/*physiology ; Enterobacteriaceae Infections/epidemiology/*transmission ; Feces/*microbiology ; Genotype ; Humans ; Intensive Care Units ; Polymerase Chain Reaction ; Prevalence ; Republic of Korea/epidemiology ; beta-Lactamases/*metabolism

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

OBJECTIVETo understand pathogen patterns of enteric infectious diseases and its impact on this pattern due to aggregation of a great deal of foreign visitors during Beijing Olympic Games.

METHODSThe diarrheal patient's rectal swabs and stool specimens were collected from Olympic stadium and hospitals of four districts, including Dongcheng, Xicheng, Haidian and Chaoyang. Enteric multiple pathogens were detected from the total 45 specimens. The culture method was used for the enteric bacteria, ELISA and RT-PCR for the enteric viruses. Molecular typing of Salmonella Enteritidis isolation was completed by PFGE.

RESULTSIt was found that 26 out of 45 cases were positive with 57.8 percent for pathogen detection, and 24 were identified as enteric pathogenic bacteria, including Vibrio parahaemolyticus, Salmonella, diarrheagenic Escherichia coli and Campylobacter jejuni, two as norovirus. There were mixed infections of two pathogenic bacteria for three cases. Ten kinds of pathogens were detected from foreign cases, while five kinds from Chinese cases. A total of 5 PFGE patterns were identified in 10 Salmonella Enteritidis isolates from national and foreign diarrheal cases, which were concentrative in some extent.

CONCLUSIONVibrio parahaemolyticus, Salmonella, diarrheagenic Escherichia coli and Campylobacter jejuni were found to be the primary bacterial pathogens during the Olympic Games. Enteric virus infection existed in summer diarrhea.

Adult ; Bacterial Typing Techniques ; Campylobacter jejuni ; classification ; isolation & purification ; China ; Diarrhea ; epidemiology ; etiology ; microbiology ; virology ; Enterobacteriaceae ; classification ; isolation & purification ; Enterovirus ; isolation & purification ; Escherichia coli Infections ; microbiology ; Female ; Humans ; Male ; Salmonella ; classification ; isolation & purification ; Shigella ; classification ; isolation & purification ; Sports ; Vibrio parahaemolyticus ; classification ; isolation & purification

We investigated the occurrence and genetic basis of AmpC beta-lactamase (AmpC)-mediated antibiotic resistance, by examining Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates at a university hospital, from 2007 to 2010. The ampC genes were detected by multiplex AmpC PCR, and AmpC-positive strains were subjected to DNA sequencing. Extended-spectrum beta-lactamase (ESBL) production was assessed using the ESBL disk test based on the utilization of boronic acid. Carbapenem-resistant isolates were further investigated by the modified Hodge test, a carbapenemase inhibition test and SDS-PAGE experiments. AmpC expression was detected in 1.6% of E. coli (39 DHA-1, 45 CMY-2, and 1 CMY-1) isolates, 7.2% of K. pneumoniae (39 DHA-1, 45 CMY-2, and 1 CMY-1) isolates, and 2.5% of P. mirabilis (8 CMY-2 and 1 CMY-1) isolates. Of the 198 acquired AmpC producers, 58 isolates (29.3%) also produced an ESBL enzyme. Among the acquired AmpC-producing K. pneumoniae isolates, the minimum inhibitory concentration (MIC) MIC50/MIC90 values for cefoxitin, cefotaxime, cefepime, imipenem, and meropenem were >32/>32, 16/>32, 1/16, 0.25/0.5, and <0.125/0.125 microg/mL, respectively. The MIC values for carbapenem were > or =2 microg/mL for 2 K. pneumoniae isolates, both of which carried the blaDHA-1 gene with a loss of OmpK36 expression, but were negative for carbapenemase production. The acquisition of AmpC-mediated resistance in K. pneumoniae isolates increased, as did the proportion of AmpC and ESBL co-producers among the hospital isolates. The accurate identification of isolates producing AmpCs and ESBLs may aid in infection control and will assist physicians in selecting an appropriate antibiotic regimen.
Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics ; DNA, Bacterial/genetics ; Enterobacteriaceae Infections/*epidemiology/*microbiology ; Escherichia coli/drug effects/enzymology/isolation & purification ; Hospitals, University/statistics & numerical data ; Humans ; Klebsiella pneumoniae/drug effects/enzymology/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Multiplex Polymerase Chain Reaction ; Proteus mirabilis/drug effects/enzymology/isolation & purification ; Republic of Korea/epidemiology ; beta-Lactamases/*genetics