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Coliform mastitis is still significantly problematic disease to treat and control in practice, which is testament to the intricacy and mutability of the condition. We examined 103 mastitis E. coli isolates collected from 22 dairy farms in eastern China, for their serotypes and prevalence of virulence and antimicrobial resistance genes. Of the sixteen serotypes characterized through serum agglutination test, O39 followed by O92 and O123 were the most predominant serovars. The genotyping of the isolates was also determined by using ERIC-PCR. Phylogenetic analysis of DNA fingerprints was performed by using SPSS data editor, which yielded ten distinct genotypes (A-J). 14 virulence genes and 10 antimicrobial resistance genes were checked in all 103 isolates by PCR assay. Most prevalent virulence genes were, TraT, FimH, papC, iucD, F4 (K88) and sfa; but F17A, F41, stx1, intimin, CNF1, CNF2, LT and ST were not present in any isolate. Among all investigated resistance genes, 48% isolates carried CTX-M and qnrS. In addition, tetA, tetB, sul1, sul2 were also found in high frequency. Statistical analysis revealed an unconditional association between virulence and resistance genes as the P<0.05. To our knowledge, this is most updated report on serotypes, genotypes, prevalence of resistance and virulence genes, and their significant association with each other in mastitis E. coli isolates from eastern China. [ABSTRACT FROM AUTHOR]

Integrative and conjugative elements (ICEs) of the ICESa2603 family have been isolated from several species of Streptococcus spp.; however, the comparative genomic and evolutionary analyses of these particular ICEs are currently only at their initial stages. By investigating 13 ICEs of the ICESa2603 family and two ICESa2603 family-like ICEs derived from diverse hosts and locations, we have determined that ICEs comprised a backbone of 30 identical syntenic core genes and accessory genes that were restricted to the intergenic sites or the 3'-end of the non-conserved domain of core genes to maintain its function. ICESa2603 family integrase IntICESa2603 specifically recognized a 15-bp att sequence (TTATTTAAGAGTAAC) at the 3'-end of rplL, which was highly conserved in genus Streptococcus. Phylogenetic analyses suggest that extensive recombination/insertion and the occurrence of a hybrid/mosaic in the ICESa2603 family were responsible for the significant increase in ICE diversity, thereby broadening its host range. Approximately 42.5 and 38.1% of the tested Streptococcus suis and Streptococcus agalactiae clinical isolates respectively contained ICESa2603 family Type IV secretion system (T4SS) genes, and 80.5 and 62.5% of which also respectively carried intICESa2603, indicating that ICESa2603 family is widely distributed across these bacteria. Sequencing and conjugation transfer of a novel sequence type ST303 clinical S. suis isolate HB1011 demonstrated that the 89K-subtype ICESsuHB1011 retained its transferrable function, thereby conferring tetracycline and macrolide resistance. [ABSTRACT FROM AUTHOR]

BACKGROUND Acquiring antibiotic resistance genes may change an organism's genetic characteristics and the effect of antibiotics, resulting in a rapid transmission of microbial pathogens. The objectives of this experiment were to identify the features of Streptococcus suis ( S. suis) isolated from three pig farms in China which are geographically isolated. RESULTS Among the isolates, 56.52% were sequence type 7 (ST7), followed by ST1 (26.09%), indicating that ST7 prevails in China, as revealed by multi-locus sequence typing (MLST). Statistical analysis indicated an association between geography, sequence types and antibiotic resistance genotypes. 66.67% of the isolates in Sichuan province presented a ( ermB− + mefA− + tetO− + tetM−) + ST7 type. The tetM++ST7 type was the most prevalent in Jiangsu province, whereas the strains from Hebei province had a phenotype ermB+ +tetO+ +ST1 (63.64%). Pulsed-field gel electrophoresis (PGFE) pattern A2 with 100% similarity reflected the clonal dissemination between Sichuan and Jiangsu provinces. Strains carrying or not carrying antibiotic resistance genes presented different PFGE patterns in Hebei province. CONCLUSION ST7 is widespread in many regions of China and a clonal dissemination occurred between Sichuan and Jiangsu provinces in diseased pigs. However, ST1 strains with macrolide and tetracycline resistance ( ermB++ tetO++ST1) isolated from a farm in Hebei province demonstrated that the genetic diversity was contributed by horizontal acquiring of ermB and tetO carrying elements. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study aimed to detect integrons, β-lactamase genes and to characterize sulfonamide resistant E. coli isolates recovered from poultry. All the isolates (n=38) were investigated for the presence of integrons, Sul1, Sul2, Sul3 genes by PCR. Class 1 and class 2 integron were present in 79 and 16%, respectively. Additional resistance gene cassette embedded in class 1 and 2 integrons was aadA1, aadA5, dfrA17 and aadA22, dfrA, respectively. Sul1 and Sul2 genes were detected in 42.1 and 60.5% isolates, respectively. Both the Sul1 and Sul2 were present in 23% isolates. However, Sul3 gene was not present. Co-existence of Sul1 and Sul2 with class 1 integrons was found in 28.9 and 60.5% of class 1 integron positive isolates, respectively. Whereas, a less percentage of isolates showed a low level of resistance to ß-lactams and no blaCTX-M, blaSHV and blaTEM was found. The MIC results showed resistance to sulfadiazine and sulfamethoxazole-trimethoprim in 88 and 84% isolates, resistance to penicillin, ampicillin, amoxicillin was 52, 52 and 44%, respectively. Chloramphenicol, florfenicol, tetracycline and gentamycin resistance was found in 51, 5, 42 and 67% isolates, respectively. This study revealed high frequency of class 1 integrons, Sul genes among poultry E. coli isolates, therefore further spread of Sul genes and integrons is predictable. [ABSTRACT FROM AUTHOR]

Prevalence of sub-clinical and clinical coliform mastitis with antimicrobial sensitivity profile of various mastitis-causing organisms was investigated. Milk samples collected from 299 cows infected with clinical mastitis to evaluate the prevalence of coliform mastitis and 1660 quarters milk samples randomly collected from 415 lactating cows for detection of subclinical mastitis (SCM) by Hangzhou Mastitis Test (HMT). SCM at quarters and cow level was recorded to be 20.2 and 52.3%, respectively. Occurrence of SCM in left rear quarter was high (26.7%). Statistical analysis of risk factors showed, cows with 6-9 years of age (P=0.046; Odds ratio (OR), ±1.414; 95% confidence interval (CI)=1.006-1.988 and 60.7%), cows with 4-7 calves (P=0.028; OR, ±1.502; 95% CI=1.044-2.160 and 62.2%), and cows in late stage of lactation (P=0.039; OR, ±1.947; 95% CI=1.023-3.702 and 68%), were more susceptible to SCM. All the 115 organisms from SCM milk samples and 103 Escherichia coli from CM samples were confirmed by PCR techniques. Minimum inhibitory concentration (MIC) results revealed that E. coli isolates were resistant to penicillin group (93-99%), fluoroquinolones (40-74%), cephalosporins (54-66%), oxytetracycline (91%), gentamycin (82%), SUL-TRM (88%) and were sensitive to florfenicol. Staphylococcus aureus isolates were resistant to ampicillin (91%), oxytetracycline (59%) and methicillin (29%). Streptococcus agalactiae isolates were 8 to 15% resistant to used antimicrobials. In conclusion, cows with SCM were reservoir of various bacterial pathogens and high prevalence of E. coli in clinical mastitis milk could be major complications for mastitis treatment due to their multidrug resistance profile. [ABSTRACT FROM AUTHOR]

A total of 30 Escherichia coli isolates from 50 random samples of diarrheic calves were screened against resistance to sulfonamides. Minimum inhibitory concentration (MIC) by microdilution method indicated that 25/30 (83.3%) were found resistant to sulfadimidine, 27/30 (90%) were resistant to sulfadiazine, while 22/30 (73.3%) were found resistant to sulfamethaxole. These phenotypically sulfonamide resistant isolates were then probed for the presence of Sul genes (Sul-1-3) by polymerase chain reaction (PCR) using specific primers. PCR results revealed that 23/25, 25/27 and 20/22 isolates carried Sul-1 gene, respectively. Interestingly, all these isolates were found negative for the presence of Sul-2 and Sul-3 genes. Of note, no Sul genes could be verified in 02 phenotypically resistant isolates. The abundance of Sul1 gene and absence of Sul-2 and Sul-3 genes indicating a clonal expansion of sulfonamide resistant E. coli that might be linked to excessive abuse of sulfonamides in animals. [ABSTRACT FROM AUTHOR]

This study was carried out to determine the genotypes, virulence factors and antimicrobial resistance traits of 34 Staphylococcus aureus isolated from subclinical mastitis in Eastern China. Minimal inhibitory concentration (MIC) results showed resistance to erythromycin in all isolates. A high frequency of Methicillin resistant S. aureus (MRSA; 29%) was observed and these isolates were also highly resistant to penicillin, oxacillin, oxytetracycline and chloramphenicol than methicillin sensitive S. aureus (MSSA) isolates. Thirteen pathogenic factors and seven resistance genes including mecA and blaZ gene were checked through PCR. The spaX gene was found in all isolates, whereas cna, spaIg, nuc, clfA, fnbpB, hlA, hlB and seA were present in 35, 79, 85, 59, 35, 85, 71 and 38% isolates, respectively. Nine isolates carried a group of 8 different virulence genes. Moreover, macrolide resistance genes ermB and ermC were present in all isolates. High resistance rate against methicillin was found but no isolate was positive for mecA gene, whereas blaZ and tetK were detected in 82 and 56% isolates, respectively. Genes; fnbpA, seB, seC, seD, dfrK and tetM were not found in any isolate. The statistical association between phenotypic resistance and virulence genes showed, clfA, fnbpB, hlB and seA, were potentially associated with penicillin G, ciprofloxacin, methicillin, chloramphenicol, trimethoprim and oxytetracycline resistance (P≤0.05). REP-PCR based genotyping showed seven distinct genotypes (A-G) prevalent in this region. This study reports the presence of multidrug resistant S. aureus in sub-clinical mastitis which were also highly virulent that could be a major obstacle in the treatment of mastitis in this region of China. [ABSTRACT FROM AUTHOR]