Clostridium perfringens causes diarrhea and other diseases in animals and humans. We investigated the prevalence, toxin gene profiles, and antibiotic resistance of C. perfringens isolated from diarrheic dogs (DD) and non-diarrheic dogs (ND) in two animal hospitals in Seoul, Korea. Fecal samples were collected from clinically DD (n = 49) and ND (n = 34). C. perfringens was isolated from 31 of 49 DD (63.3%) and 21 of 34 ND dogs (61.8%). All C. perfringens strains were positive for the α toxin gene, but not for the β, ε, or ι toxin genes; therefore, all strains were identified as type A C. perfringens. All isolates were cpe-negative, whereas the β2 toxin gene was identified in 83.9% and 61.9% of isolates from DD and ND, respectively. Most isolates were susceptible to ampicillin (94%), chloramphenicol (92%), metronidazole (100%), moxifloxacin (96%), and imipenem (100%). However, 25.0% and 21.2% of isolates were resistant to tetracycline and clindamycin, respectively. Molecular subtyping of the isolated strains was performed by using pulsed-field gel electrophoresis. Fifty-two isolates were classified into 48 pulsotypes based on more than 90% similarity of banding patterns. No notable differences were observed among the isolates from DD and ND.
Ampicillin ; Animals ; Bacterial Toxins ; Chloramphenicol ; Clindamycin ; Clostridium perfringens ; Clostridium ; Diarrhea ; Dogs ; Drug Resistance ; Drug Resistance, Microbial ; Electrophoresis, Gel, Pulsed-Field ; Hospitals, Animal ; Humans ; Imipenem ; Korea ; Metronidazole ; Prevalence ; Seoul ; Tetracycline

OBJECTIVES: The aim of this study was to determine the prevalence of asymptomatic carriers of group A β-hemolytic streptococci (GAS) in children living in a rural community and to investigate the association between episodes of acute pharyngitis and carrier status. METHODS: Throat swabs were collected from September to November 2013 among children 5-13 years of age from a rural community (Maria Ignacia-Vela, Argentina). The phenotypic characterization of isolates was performed by conventional tests. Antimicrobial susceptibility was assayed for penicillin, tetracycline, chloramphenicol, erythromycin, and clindamycin (disk diffusion). The minimum inhibitory concentration was determined for penicillin, cefotaxime, tetracycline, and erythromycin. RESULTS: The carriage of β-hemolytic streptococci was detected in 18.1% of participants, with Streptococcus pyogenes in 18 participants followed by S. dysgalactiae ssp. equisimilis in 5. The highest proportion of GAS was found in 8 to 10-year-old children. No significant association between the number of episodes of acute pharyngitis suffered in the last year and the carrier state was detected (p>0.05). Tetracycline resistance (55.5%) and macrolide-resistant phenotypes (11.1%) were observed. Resistance to penicillin, cefotaxime, or chloramphenicol was not expressed in any streptococcal isolate. CONCLUSIONS: The present study demonstrated significant throat carriage of GAS and the presence of group C streptococci (S. dysgalactiae ssp. equisimilis) in an Argentinian rural population. These results point out the need for continuous surveillance of GAS and non-GAS carriage as well as of antimicrobial resistance in highly susceptible populations, such as school-aged rural children. An extended surveillance program including school-aged children from different cities should be considered to estimate the prevalence of GAS carriage in Argentina.
Argentina* ; Carrier State ; Cefotaxime ; Child* ; Chloramphenicol ; Clindamycin ; Erythromycin ; Humans ; Microbial Sensitivity Tests ; Penicillins ; Pharyngitis ; Pharynx* ; Phenotype ; Prevalence ; Rural Population ; Streptococcus pyogenes* ; Streptococcus* ; Tetracycline ; Tetracycline Resistance

The present study was done to scrutinize the possible relation between infective genes and antimicrobial resistance in Enterococcus faecalis and Enterococcus faecium. Considering the fact that the presence of recognized infective determinants among clinical isolates may promote the emergence of infections and persistence of Enterococci in hospital settings, which can lead to an increase in antimicrobial resistance. 175 E. faecalis and 67 E. faecium isolated from clinical specimens were used. The isolates were identified, and then antibiotic susceptibility testing was performed. The MIC of vancomycin and teicoplanin were determined by broth microdilution method. The presence of infective genes esp, hyl and asa₁ was scrutinized using PCR. Of the 280 enterococcal isolates, 175 (62.5%) isolates were identified as E. faecalis, 67 (24%) as E. faecium and 38 (13.5%) as Enterococcus spp. The results of the antibiotic susceptibility testing showed resistance rates of 5% and 73% to vancomycin and teicoplanin in E. faecalis and E. faecium isolates, respectively. The statistical analysis showed that the esp infective gene has significant associations with ciprofloxacin, erythromycin and tetracycline in E. faecium and with chloramphenicol in E. faecalis strains; the hyl with teicoplanin and vancomycin in E. faecium strains; and also asa₁ with vancomycin in E. faecium and with ampicillin and chloramphenicol in E. faecalis strains. Regarding the relationships between virulence genes and antibiotic resistance in strains of E. faecalis and E. faecium, detection of infective factors associated with invasive diseases has become a major issue of concern.
Ampicillin ; Anti-Bacterial Agents ; Chloramphenicol ; Ciprofloxacin ; Drug Resistance, Microbial ; Enterococcus ; Enterococcus faecalis ; Enterococcus faecium ; Erythromycin ; Iran ; Methods ; Polymerase Chain Reaction ; Teicoplanin ; Tetracycline ; Vancomycin ; Virulence

BACKGROUND: Extended-spectrum cephalosporins and fluoroquinolones are important antimicrobials for treating invasive salmonellosis, and emerging resistance to these antimicrobials is of paramount concern. METHODS: A total of 30 Salmonella spp. clinical isolates recovered in Gyeongsangbuk-do from 2012 to 2013 were characterized using antibiotic resistance profiles and pulsed-field gel electrophoresis (PFGE). RESULTS: A high prevalence of multidrug-resistant isolates, mainly showing an ampicillin, nalidixic acid, chloramphenicol resistance pattern, was observed. Four extended-spectrum beta-lactamase (ESBL)-producing isolates (3 CTX-M-15 isolates and 1 CTX-M-27 isolate) were found. The bla(CTX-M-27) gene was carried by an IncF conjugative plasmid in the S. Infantis isolate. The bla(CTX-M-15) gene were carried by an IncF (2 isolates) or IncHI2 (1 isolate) conjugative plasmid in S. Enteritidis. In addition, a single mutation of GyrA, Ser83Thr (1 isolates), Asp87Tyr (9 isolates), Asp87Gly (4 isolates), and Asp87Leu (3 isolates), was detected in nalidixic acid-resistant Salmonella spp. isolates. XbaI PFGE analysis of all isolates revealed more than 19 different pulsotypes. The most common S. Enteritidis PFGE pattern (SEGX01.003) was associated with a larger number of cases of invasive salmonellosis than all other patterns. CONCLUSION: The information from our study can assist in source attribution, outbreak investigations, and tailoring of interventions to maximize disease prevention.
Ampicillin ; beta-Lactamases ; Cephalosporins ; Chloramphenicol Resistance ; Drug Resistance ; Drug Resistance, Microbial ; Electrophoresis, Gel, Pulsed-Field ; Fluoroquinolones ; Gyeongsangbuk-do ; Nalidixic Acid ; Plasmids ; Prevalence ; Salmonella Infections ; Salmonella*

BACKGROUND: Bacteroides fragilis group organisms are the most frequently isolated anaerobes in human infections. Increasing resistance to various antimicrobial agents is a significant problem in choosing appropriate antimicrobial agents to treat anaerobic infections. Periodic monitoring of the regional resistance trends of B. fragilis group isolates is needed. METHODS: A total of 466 nonduplicate clinical isolates of B. fragilis group organisms (276 B. fragilis, 106 Bacteroides thetaiotaomicron, and 84 other B. fragilis group organisms) were collected during the 8-yr period from 1997 to 2004 in a Korean university hospital. Minimum inhibitory concentrations to various antimicrobial agents were determined by the CLSI agar dilution method. RESULTS: Eight isolates were resistant to imipenem. Additionally, the resistance rates to cefotetan were decreased in B. thetaiotaomicron, while those for clindamycin were significantly increased compared to the rates found in previous studies. Depending on species, resistance rates were 1-4% for imipenem, 1-6% for piperacillin-tazobactam, 4-11% for cefoxitin, 33-49% for piperacillin, 14-60% for cefotetan, and 51-76% for clindamycin. No isolates were resistant to chloramphenicol or metronidazole. CONCLUSIONS: Piperacillin-tazobactam, cefoxitin, imipenem, chloramphenicol, and metronidazole are still active against B. fragilis group isolates, while clindamycin no longer has a value as an empirical therapeutic agent in Korea. Furthermore, this study identified the first imipenem-resistant B. fragilis group isolates in Korea.
Anti-Bacterial Agents/pharmacology ; Bacteroides/classification/*drug effects/isolation & purification ; Bacteroides fragilis/drug effects/isolation & purification ; Cefoxitin/pharmacology ; Chloramphenicol/pharmacology ; *Drug Resistance, Multiple, Bacterial ; Humans ; Imipenem/pharmacology ; Metronidazole/pharmacology ; Microbial Sensitivity Tests ; Penicillanic Acid/analogs & derivatives/pharmacology ; Piperacillin/pharmacology ; Republic of Korea

BACKGROUND: The genes of metallo-beta-lactamase (MBL), a powerful carbapenemase, are carried as a part of the mobile gene cassettes inserted into integrons playing an important role in rapid dissemination of antibiotic resistance genes among bacterial isolates. In this study, we investigated carbapenemase genes and class 1 integrons integrated into the gene cassettes in imipenem-non susceptible P. aeruginosa. METHODS: From July 2006 to March 2008, 81 consecutive, non-duplicate, imipenem-non susceptible P. aeruginosa were isolated at Chungnam National University Hospital in Chungcheong province of Korea. The modified Hodge and double disk synergy tests were conducted for the screening of carbapenemase and MBL production, respectively, and PCR and DNA sequencing were performed for the detection of carbapenemase genes and class 1 integron gene cassettes. We also employed the repetitive element sequence-based (Rep)-PCR method for an epidemiologic study. RESULTS: MBLs were detected in 13.6% (11/81) of imipenem-non susceptible P. aeruginosa. Ten isolates were found to carry blaIMP-1, whereas 1 isolate was found to carry a blaVIM-2. All of the IMP-1-producing strains harbored 4.0 kb class 1 integron containing chloramphenicol, aminoglycoside, and beta-lactam- resistant genes. However, blaIMP-1 was not detected at class 1 integron. A 2.5 kb class 1 integron harboring blaVIM-2 was detected in a VIIM-2- producing strain. One identical pattern was observed in ten IMP-1 producing strains. CONCLUSION: IMP-1 producing P. aeruginosa strains are currently distributed throughout Chungcheong province of Korea. In particular, all of the strains harbored class 1 integrons containing variant antibiotic resistance gene cassettes.
Bacterial Proteins ; beta-Lactamases ; Chloramphenicol ; Drug Resistance, Microbial ; Integrons ; Korea ; Mass Screening ; Polymerase Chain Reaction ; Pseudomonas ; Pseudomonas aeruginosa ; Sequence Analysis, DNA ; Sprains and Strains

BACKGROUND: Nontyphoid Salmonella (NTS) is a leading cause of human food-borne enteritiS. It has been known that integron, a naturally occurring gene capture and expression element, plays an important role in the development and dissemination of multidrug-resistance. In this study, we investigated the prevalences and molecular characteristics of integrons in NTS clinical strains. MATERIALS AND METHODS: Between 1995-96 and 2000-03, a total 261 NTS clinical strains comprising 39 serotypes were collected from clinical specimens. All strains were serotyped, and the MICs of ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim were determined by agar dilution method. Integrons were detected by PCR amplification of integrase genes, and gene cassettes were determined by PCR and sequencing. Conjugation experiments were performed using E. coli J53 as a recipient. The clonal relationship was analyzed by pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 261 strains tested, class 1 integrons were present in 21 strains (8.0%). Class 2 and class 3 integrons were not found. The integron-positive rate was higher in S. Typhimurium (24.2% [8/33]) than in S. Enteritidis (2.0% [3/153]). Overall rates of antimicrobial resistance were higher in integron-positive strains. dhfr12-orfF-aadA2 gene cassette was detected in 5 strains, aadA2 in 4 strains, dhfr17-orfF-aadA5 in 2 strains, and addA1 in 1 strain. Ten integron-positive transconjugants were successfully selected. Among 8 integron-positive strains of S. Typhimurium, 7 had similar PFGE patterns. CONCLUSION: This study suggests that integrons are already playing a significant role in antimicrobial resistance in NTS. Continuous monitoring is needed to detect the emergence and spread of integron-mediated antimicrobial resistance.
Agar ; Ampicillin ; Chloramphenicol ; Drug Resistance, Microbial ; Electrophoresis, Gel, Pulsed-Field ; Enteritis ; Humans ; Integrases ; Integrons ; Polymerase Chain Reaction ; Prevalence ; Salmonella ; Sprains and Strains ; Streptomycin ; Sulfamethoxazole ; Tetracycline ; Trimethoprim

BACKGROUND: Nontyphoid Salmonella (NTS) is a leading cause of human food-borne enteritiS. It has been known that integron, a naturally occurring gene capture and expression element, plays an important role in the development and dissemination of multidrug-resistance. In this study, we investigated the prevalences and molecular characteristics of integrons in NTS clinical strains. MATERIALS AND METHODS: Between 1995-96 and 2000-03, a total 261 NTS clinical strains comprising 39 serotypes were collected from clinical specimens. All strains were serotyped, and the MICs of ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim were determined by agar dilution method. Integrons were detected by PCR amplification of integrase genes, and gene cassettes were determined by PCR and sequencing. Conjugation experiments were performed using E. coli J53 as a recipient. The clonal relationship was analyzed by pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 261 strains tested, class 1 integrons were present in 21 strains (8.0%). Class 2 and class 3 integrons were not found. The integron-positive rate was higher in S. Typhimurium (24.2% [8/33]) than in S. Enteritidis (2.0% [3/153]). Overall rates of antimicrobial resistance were higher in integron-positive strains. dhfr12-orfF-aadA2 gene cassette was detected in 5 strains, aadA2 in 4 strains, dhfr17-orfF-aadA5 in 2 strains, and addA1 in 1 strain. Ten integron-positive transconjugants were successfully selected. Among 8 integron-positive strains of S. Typhimurium, 7 had similar PFGE patterns. CONCLUSION: This study suggests that integrons are already playing a significant role in antimicrobial resistance in NTS. Continuous monitoring is needed to detect the emergence and spread of integron-mediated antimicrobial resistance.
Agar ; Ampicillin ; Chloramphenicol ; Drug Resistance, Microbial ; Electrophoresis, Gel, Pulsed-Field ; Enteritis ; Humans ; Integrases ; Integrons ; Polymerase Chain Reaction ; Prevalence ; Salmonella ; Sprains and Strains ; Streptomycin ; Sulfamethoxazole ; Tetracycline ; Trimethoprim

Chloramphenicol-resistant gene was cloned and analyzed by constructing genomic DNA library of Serratia marcescens KMR-3. It showed that cloned chloramphenicol-resistant gene encoded a protein product of 397 amino acids. The protein belonged to PRK10473 protein, and it showed 92% similarity to drug resistance transporter, Bcr/CflA subfamily of Serratia proteamaculans 568. Regulation elements including promoter, terminator, Shine-Dalgarno (SD) sequence and transcription start site also were identified.
Amino Acid Sequence ; Base Sequence ; Chloramphenicol Resistance ; genetics ; Cloning, Molecular ; Molecular Sequence Data ; Serratia marcescens ; classification ; genetics

The aim of this study was to investigate antimicrobial susceptibilities and macrolide resistance mechanisms of beta-hemolytic viridans group streptococci (VGS) in a tertiary Korean hospital. Minimum inhibitory concentrations (MICs) of seven antimicrobials were determined for 103 beta-hemolytic VGS isolated from various specimens. The macrolide resistance mechanisms of erythromycin-resistant isolates were studied by the double disk test and polymerase chain reaction (PCR). The overall resistance rates of beta-hemolytic VGS were found to be 47.5% to tetracycline, 3.9% to chloramphenicol, 9.7% to erythromycin, and 6.8% to clindamycin, whereas all isolates were susceptible to penicillin G, ceftriaxone, and vancomycin. Among ten erythromycin-resistant isolates, six isolates expressed a constitutive MLSB (cMLSB) phenotype, and each of the two isolates expressed the M phenotype, and the inducible MLSB (iMLSB) phenotype. The resistance rates to erythromycin and clindamycin of beta-hemolytic VGS seemed to be lower than those of non-beta-hemolytic VGS in our hospital, although cMLSB phenotype carrying erm(B) was dominant in beta-hemolytic VGS.
Ceftriaxone/pharmacology ; Chloramphenicol/pharmacology ; Clindamycin/pharmacology ; Cross Infection/*genetics ; *Drug Resistance, Bacterial ; Erythromycin/pharmacology ; Humans ; Immunoenzyme Techniques ; Korea ; Macrolides/*pharmacology ; Penicillin G/pharmacology ; Phenotype ; Polymerase Chain Reaction ; Tetracycline/pharmacology ; Vancomycin/pharmacology ; Viridans Streptococci/*genetics/*metabolism