Phenotypic and Genotypic Characteristics of Streptococcus porcinus Isolated from Human Sources (original) (raw)
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Identification of Major Streptococcal Species by rrn-Amplified Ribosomal DNA Restriction Analysis
Journal of Clinical Microbiology, 2003
Amplified ribosomal DNA restriction analysis (rrn-ARDRA) is based on PCR amplification and restriction of a fragment of rRNA genes including 16S and 23S genes and the intergenic spacer. rrn-ARDRA was evaluated for the identification of species within the genus Streptococcus. A total of 148 type and reference strains of pyogenic, oral, and group D streptococci were examined in order to construct a database for identification of streptococci. The amplified product was a single band approximately 4,500 bp long. This amplicon was digested separately with three (HhaI, MboII, and Sau3A) restriction endonucleases. Respectively, 27, 26, and 28 major patterns were observed after HhaI, MboII, and Sau3A restrictions. Streptococcal strains belonging to different species had different patterns or different combination of patterns. An identification system based upon a combination of the three restriction patterns in a single database was then proposed. rrn-ARDRA was successfully applied to 11 clinical isolates whose identification to the species level was difficult to obtain by phenotypic analysis. Using a database of well-characterized strains, rrn-ARDRA is a powerful method for the identification of streptococcal isolates.
Journal of Clinical Microbiology
To better understand the emergence and transmission of antibiotic-resistant Streptococcus agalactiae, we compared phenotypic and genotypic characteristics of 52 human and 83 bovine S. agalactiae isolates. Serotypes found among isolates from human hosts included V (48.1%), III (19.2%), Ia and Ib (13.5% each), and II (5.8%). Among isolates from bovine hosts, molecular serotypes III and II were predominant (53 and 14.5%, respectively). Four and 21 different ribotypes were found among human and bovine isolates, respectively. A combination of ribotyping and serotyping showed that two bovine isolates were indistinguishable from human isolates. Resistance to tetracycline and erythromycin was more common among human (84.6% and 26.9%, respectively) than bovine (14.5% and 3.6%, respectively) isolates. tetM was found in all tetracycline-resistant human isolates, while tetO was the predominant resistance gene among bovine isolates. tet genes were found among various ribotypes. ermB, ermTR, and mefA were detected among erythromycin-resistant human isolates, while ermB was the only erythromycin resistance determinant among isolates from bovine hosts. For isolates from human hosts, erythromycin resistance genes appeared to be associated with specific ribotypes. We conclude that (i) human and bovine S. agalactiae isolates represent distinct populations; (ii) human hostassociated S. agalactiae subtypes may occasionally be transmitted to bovines; (iii) while emergence of erythromycin and tetracycline resistance appears to largely occur independently among human and bovine isolates, occasional cross-species transfer of resistant strains or transmission of resistance genes between human-and bovine-associated subtypes may occur; and (iv) dissemination of antibiotic-resistant S. agalactiae appears to include both clonal spread of resistant strains as well as horizontal gene transfer.
Predicción molecular de serotipos de Streptococcus suis aislados de granjas porcinas en México
Revista Mexicana de Ciencias Pecuarias, 2021
Infections caused by Streptococcus suis (S. suis) pose a problem for the pig industry worldwide. Pigs often carry multiple serotypes of S. suis in the upper respiratory tract, where S. suis is frequently isolated from. The clinical diagnosis of the infection is presumptive and is generally based on clinical signs, the age of the animal and macroscopic lesions. In the laboratory, identification of S. suis is performed biochemically, and then, serotyping is performed with antisera to determine the serotype, but these tests can be inconclusive. To date, there are few studies that have documented the presence and diversity of S. suis serotypes in Mexico. In the present study, it was characterized S. suis strains from Mexican pig farms using molecular approaches; samples were first processed by PCR of the gdh gene to detect S. suis. Positive samples were then subjected to a two-step multiplex PCR (cps PCR) to detect and characterize each strain; the first step consisted of a grouping PCR...
Comparative Immunology, Microbiology and Infectious Diseases, 2014
This study characterized carriage and clinical pneumococcal isolates for serotypes, penicillin susceptibility, virulence genes and restriction fragment length polymorphism (RFLP) pattern of penicillin binding protein (PBP) genes. DNA fingerprint of isolates was generated by BOX-PCR. Majority of serotypes were 23F followed by 19F, 19A and 6A. Twenty-four percent of isolates were penicillin non-susceptible (PNSP). All of the targeted virulence genes were detected in all isolates with the exception of pili; 20.6% (n = 22) for PI-1 and 14.0% (n = 15) for PI-2. Of the 13 isolates which carried both PI-1 and PI-2, 10 were of clinical origin. Digested pbp-DNA produced three PBP-RFLP profiles for pbp1a (A1 to A3), six profiles for pbp2b (B1 to B6) and seven for pbp2x (X1 to X7) mostly in PNSPs. Based on BOX-PCR analysis, the majority of isolates were genetically diverse with a small number of potentially related isolates carrying pili genes. No obvious genotypic association was observed pertaining to carriage and clinical origin of isolates.
Antimicrobial Agents and Chemotherapy, 2005
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Genotyping of Streptococcus Pyogenes Isolates using Optimized RAPD-PCR Protocol
Biological Journal of Microorganism, 2019
Introduction: Streptococcus pyogenes causes a variety of infectious and non-infectious diseases. Typing of S. pyogenes isolates is one of the essential tools in the epidemiological studies of this bacterium. Random Amplified Polymorphic DNA (RAPD) is a rapid, easy and inexpensive PCR-based typing technique. Low reproducibility of RAPD-PCR is the main disadvantage of this method which will be resolved by optimization of RAPD-PCR protocol. Materials and methods: In this study, optimization of RAPD-PCR protocol including DNA extraction method, primer type, concentrations of PCR reagents, and PCR program was performed using the factorial design of experiments for S. pyogenes ATCC 19615 as a standard strain. Then, sixteen S. pyogenes isolates were genotyped by using optimized protocol. Typability, reproducibility, and discriminatory power of the optimized protocol were examined. Results: Among three DNA extraction methods and seven primers that were used, modified set buffer DNA extraction method and P14 primer were selected, respectively. Optimum concentration of PCR reagents were 3 mM MgCl2, 150 pmol primers, 0.2 mM dNTPs, 10 ng template DNA, and 2 U Taq DNA polymerase and the optimum PCR program consisted of an initial denaturation for 4 min at 94°C followed by 45 cycles of 1 min at 94°C, 2 min at 31°C, 2 min at 72°C, and a final extension at 72°C for 10 min. Results of optimized RAPD-PCR were reproducible for S. pyogenes ATCC 19615 and all S. pyogenes isolates. Calculated discriminatory power was satisfactory (DI=1). Sixteen S. pyogenes isolates belonged to sixteen strains which were classified into 3 main clusters on a similarity level of 14%. Discussion and conclusion: A suitable and reproducible RAPD-PCR protocol was obtained for genotyping of S. pyogenes isolates using RAPD-PCR optimization. The optimized protocol in the present study can be used in subsequent experiments on RAPD-PCR profiling for epidemiological study of S. pyogenes isolates.
Journal of Clinical Microbiology, 2001
The discriminatory power, speed, and interlaboratory reproducibility of tRNA intergenic length polymorphism analysis (tDNA-PCR) combined with capillary electrophoresis was evaluated for the identification of streptococci. This method was carried out in three different laboratories under highly standardized conditions for 54 strains belonging to 18 different species. It was concluded that interlaboratory reproducibility of tDNA fingerprints produced by means of capillary electrophoresis was sufficiently high to permit the exchange between different laboratories and the construction of common libraries which can be consulted for comparison with fingerprints obtained independently in separate laboratories. In a second step, 17 other species were included in the study and examined in one of the participating laboratories. All Streptococcus species studied, except S. mitis, S. oralis, S. parasanguinis, S. pneumoniae, S. thermophilus, and S. vestibularis, showed distinguishable tDNA fingerprints. A database of well-characterized strains was constructed to enable computeraided identification of unknown streptococcal isolates.
Genotypic diversity of Streptococcus suis strains isolated from humans in Thailand
European Journal of Clinical Microbiology & Infectious Diseases, 2018
The purpose of this study is to characterize Streptococcus suis isolates recovered from human infections regarding serotype distribution, genotypic profile, clinical manifestations, and epidemiology. A total of 668 S. suis isolates recovered from human infections in Thailand were characterized based on serotyping by multiplex PCR and co-agglutination, genotypic profiles by multilocus sequence typing, and PCR for virulence-associated genes, as well as review of medical records. Serotype 2 (94.6%) was predominant, followed by serotype 14 (4.5%), 24 (0.45%), 5 (0.3%), and 4 (0.15%). Multilocus sequence typing analyses revealed seven clonal complexes (CC): CC1 (56.43%), CC104 (31.74%), CC233/379 (5.4%), CC25 (4.5%), CC28 (0.9%), CC221/234 (0.6%), CC94 (0.15%), and two singletons. The CC1 group contained serotype 2 and 14 isolates, while CC25, 28, 104, and 233/379 consisted of serotype 2 isolates only. CC221/234 contained serotype 5 and 24 isolates, whereas the single serotype 4 isolate belonged to CC94. Two singletons contained serotype 5 (ST235) and 2 (ST236) isolates. Our data showed that ST1 isolates were more associated with meningitis than those of other STs (p < 0.001). The major route of infection was shown to be close contact with infected pigs or contaminated raw pork-derived products, including occupational exposure and recent consumption of raw pork products. This study revealed a relatively large number of CCs of S. suis causing human infection in Thailand. Among them, CC1 followed by CC104, with serotype 2 isolates, are predominant. Food safety campaigns and public health interventions would be important for controlling the S. suis infection in humans.