scholarly journals Molecular characterization of Streptococcus pyogenes group A isolates from a tertiary hospital in Lebanon

2014 ◽  
Vol 63 (9) ◽  
pp. 1197-1204 ◽  
Author(s):  
Nathalie M. Karaky ◽  
George F. Araj ◽  
Sima T. Tokajian
Keyword(s):  
Streptococcus Pyogenes ◽  
Susceptibility Testing ◽  
Clinical Manifestations ◽  
Tertiary Hospital ◽  
Human Pathogens ◽  
Genetic Characteristics ◽  
Epidemiological Analysis ◽  
Group A ◽  
Resistant Strains

Streptococcus pyogenes [Group A Streptococcus (GAS)] is one of the most important human pathogens, responsible for numerous diseases with diverse clinical manifestations. As the epidemiology of GAS infections evolves, a rapid and reliable characterization of the isolates remains essential for epidemiological analysis and infection control. This study investigated the epidemiological patterns and genetic characteristics of 150 GAS isolates from a tertiary hospital in Lebanon by emm typing, superantigens (SAgs) detection, PFGE and antibiotic profiling. The results revealed 41 distinct emm types, the most prevalent of which were emm89 (16 %), emm12 (10 %), emm2 (9 %) and emm1 (8 %). Testing for the presence of superantigens showed that speB (87 %), ssa (36 %) and speG (30 %) were predominant. PFGE detected 39 pulsotypes when a similarity cut-off value of 80 % was implemented. Antibiotic-susceptibility testing against seven different classes of antibiotics showed that 9 % of the isolates were resistant to clindamycin, 23 % were resistant to erythromycin and 4 % showed the macrolide–lincosamide–streptogramin B (MLSB) phenotype. The emergence of tetracycline-resistant strains (37 %) was high when compared with previous reports from Lebanon. This study provided comprehensive evidence of the epidemiology of GAS in Lebanon, highlighting the association between emm types and toxin genes, and providing valuable information about the origin and dissemination of this pathogen.

scholarly journals Prevalence and Characterization of Invasive Isolates of Streptococcus pyogenes with Reduced Susceptibility to Fluoroquinolones

2005 ◽  
Vol 49 (5) ◽  
pp. 2130-2132 ◽  
Author(s):  
Jeff Powis ◽  
Allison McGeer ◽  
Carla Duncan ◽  
Ryan Goren ◽  
Joyce C. S. de Azavedo ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Susceptibility Testing ◽  
Group A Streptococcus ◽  
Invasive Group ◽  
Group A

ABSTRACT Fluoroquinolone susceptibility testing was performed on invasive group A streptococcus isolates from 1992-1993 and 2003 from Ontario, Canada. None were nonsusceptible to levofloxacin. Two of 153 (1.3%) from 1992-1993 and 7 of 160 (4.4%) from 2003 had a levofloxacin MIC of 2 μg/ml; all nine had parC mutations, and eight were serotype M6.

scholarly journals Phenotypic and Genotypic Characterization of Streptococcus pyogenes Isolates Displaying the MLSB Phenotype of Macrolide Resistance in Spain, 1999 to 2005

2007 ◽  
Vol 51 (4) ◽  
pp. 1228-1233 ◽  
Author(s):  
Emilio Pérez-Trallero ◽  
Milagrosa Montes ◽  
Beatriz Orden ◽  
Esther Tamayo ◽  
José M. García-Arenzana ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Annual Variation ◽  
Macrolide Resistance ◽  
Resistant Clone ◽  
Erythromycin Resistance ◽  
Genetic Characteristics ◽  
Group A ◽  
Rapid Diffusion ◽  
Phenotypic And Genotypic Characterization

ABSTRACT The aim of this study was to describe the genetic characteristics of Streptococcus pyogenes showing the MLSB phenotype of macrolide resistance from 1999 to 2005 in Spain and to highlight the substantial increase in these isolates in the last few years. The antimicrobial susceptibilities of 17,232 group A streptococci isolated from Madrid and Gipuzkoa from 1999 to 2005 were studied. The presence of the resistance genes ermA, ermB, mef, tetM, and tetO and the presence of the intTn and xis genes of the Tn916-Tn1545 transposon family were studied in a sample of 739 MLSB-resistant isolates. The epidemiological relationships among these isolates were analyzed by emm typing, T typing, and multilocus sequence typing. Erythromycin resistance was found in 21.3% of the isolates analyzed (annual variation of 14.3% to 28.9%). Until 2003, most erythromycin-resistant isolates showed the M phenotype, but in 2004 and 2005, about 50% of isolates showed the MLSB phenotype. Among the MLSB-resistant isolates studied, 16 clones were identified. The most prevalent clone was a strange emm11/T11/ST403 clone with a null yqiL allele. All but one of the 463 emm11/T11/ST403 isolates carried the ermB, tetM, intTn, and xis genes. The second most prevalent MLSB-resistant clone was emm28/T28/ST52, which comprised two subclones: one bacitracin-resistant, tetracycline-susceptible subclone carrying the ermB gene (n = 115) and another bacitracin-susceptible, tetracycline-resistant subclone carrying the ermB and tetM genes (n = 33). The rapid diffusion of these two clones, and especially of emm11/T11/ST403, caused the large increase in MLSB-resistant S. pyogenes isolates in Spain, suggesting a potential ability for international dissemination.

scholarly journals Antimicrobial susceptibility and molecular characterization of Salmonella serovar Ndolo isolated from outbreaks in cattle and horses

2018 ◽  
Vol 48 (12) ◽  
Author(s):  
Carolina Pantuzza Ramos ◽  
Rafael Gariglio Clark Xavier ◽  
Carlos Augusto Gomes Leal ◽  
Elias Jorge Facury Filho ◽  
Antonio Ultimo de Carvalho ◽  
...  
Keyword(s):  
Clavulanic Acid ◽  
Antimicrobial Susceptibility ◽  
Virulence Genes ◽  
Susceptibility Testing ◽  
Domestic Animals ◽  
Amoxicillin Clavulanic Acid ◽  
Resistant Strains ◽  
Human Infections ◽  
First Time

ABSTRACT: The present study aimed to describe and characterize, for the first time, two outbreaks of salmonellosis caused by Salmonella Ndolo in foals and calves in Brazil and compare the isolated strains with S. Ndolo previously identified in asymptomatic reptiles. The affected calves and foals presented fever, lethargy, and profuse diarrhea. Isolated strains were subjected to antimicrobial susceptibility testing, characterized according to virulence genes, and fingerprinted by ERIC-PCR. Salmonella Ndolo was identified in fecal samples from two foals and four calves. One isolate from a calf was resistant to amoxicillin/clavulanic acid, trimethoprim/sulfamethoxazole, and florfenicol. Strains from two other calves were resistant to oxytetracycline. All virulence genes tested were present in the isolates, and two major clusters of closely related strains were identified by ERIC-PCR, each per outbreak. This is the first report of Salmonella Ndolo infection in domestic and symptomatic animals. Previously, this serovar had been identified only in human infections. The presence of relevant virulence genes in all Salmonella Ndolo isolates and the detection of antimicrobial multi-resistant strains highlighted the importance of monitoring serovars associated with salmonellosis in domestic animals.

scholarly journals Distribution of emm type and antibiotic susceptibility of group A streptococci causing invasive and noninvasive disease

2008 ◽  
Vol 57 (11) ◽  
pp. 1383-1388 ◽  
Author(s):  
Takeaki Wajima ◽  
Somay Y. Murayama ◽  
Katsuhiko Sunaoshi ◽  
Eiichi Nakayama ◽  
Keisuke Sunakawa ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Macrolide Antibiotic ◽  
Group A Streptococcus ◽  
Acute Otitis Media ◽  
Toxic Shock ◽  
Medical Institutions ◽  
Invasive Infections ◽  
Group A ◽  
Resistant Strains ◽  
Emm Type

To determine the prevalence of macrolide antibiotic and levofloxacin resistance in infections with Streptococcus pyogenes (group A streptococcus or GAS), strains were collected from 45 medical institutions in various parts of Japan between October 2003 and September 2006. Four hundred and eighty-two strains from patients with GAS infections were characterized genetically. Strains were classified into four groups according to the type of infection: invasive infections (n=74) including sepsis, cellulitis and toxic-shock-like syndrome; acute otitis media (AOM; n=23); abscess (n=53); and pharyngotonsillitis (n=332). Among all strains, 32 emm types were identified; emm1 was significantly more common in invasive infections (39.2 %) and AOM (43.5 %) than in abscesses (3.8 %) or pharyngotonsillitis (10.2 %). emm12 and emm4 each accounted for 23.5 % of pharyngotonsillitis cases. Susceptibility of GAS strains to eight β-lactam agents was excellent, with MICs of 0.0005–0.063 μg ml−1. Macrolide-resistant strains accounted for 16.2 % of all strains, while the percentages of strains possessing the resistance genes erm(A), erm(B) and mef(A) were 2.5 %, 6.2 % and 7.5 %, respectively. Although no strains with high resistance to levofloxacin were found, strains with an MIC of 2–4 μg ml−1 (17.4 %) had amino acid substitutions at either Ser-79 or Asp-83 in ParC. These levofloxacin-intermediately resistant strains included 16 emm types, but macrolide-resistant strains were more likely than others to represent certain emm types.

scholarly journals Prophage exotoxins enhance colonization fitness in epidemic scarlet fever-causing Streptococcus pyogenes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephan Brouwer ◽  
Timothy C. Barnett ◽  
Diane Ly ◽  
Katherine J. Kasper ◽  
David M. P. De Oliveira ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Scarlet Fever ◽  
Global Public Health ◽  
Nasopharyngeal Colonization ◽  
North East ◽  
Streptolysin O ◽  
Knockout Mutants ◽  
Group A ◽  
Bacterial Superantigen

Abstract The re-emergence of scarlet fever poses a new global public health threat. The capacity of North-East Asian serotype M12 (emm12) Streptococcus pyogenes (group A Streptococcus, GAS) to cause scarlet fever has been linked epidemiologically to the presence of novel prophages, including prophage ΦHKU.vir encoding the secreted superantigens SSA and SpeC and the DNase Spd1. Here, we report the molecular characterization of ΦHKU.vir-encoded exotoxins. We demonstrate that streptolysin O (SLO)-induced glutathione efflux from host cellular stores is a previously unappreciated GAS virulence mechanism that promotes SSA release and activity, representing the first description of a thiol-activated bacterial superantigen. Spd1 is required for resistance to neutrophil killing. Investigating single, double and triple isogenic knockout mutants of the ΦHKU.vir-encoded exotoxins, we find that SpeC and Spd1 act synergistically to facilitate nasopharyngeal colonization in a mouse model. These results offer insight into the pathogenesis of scarlet fever-causing GAS mediated by prophage ΦHKU.vir exotoxins.

scholarly journals Streptolysin O concentration and activity is central to in vivo phenotype and disease outcome in Group A Streptococcus infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jenny Clarke ◽  
Murielle Baltazar ◽  
Mansoor Alsahag ◽  
Stavros Panagiotou ◽  
Marion Pouget ◽  
...  
Keyword(s):  
Septic Arthritis ◽  
Rapid Development ◽  
Clinical Manifestations ◽  
Disease Outcome ◽  
Haemolytic Activity ◽  
Human Pathogens ◽  
Streptolysin O ◽  
Group A

AbstractGroup A Streptoccocus (GAS) is among the most diverse of all human pathogens, responsible for a range of clinical manifestations, from mild superficial infections such as pharyngitis to serious invasive infections such as necrotising fasciitis and sepsis. The drivers of these different disease phenotypes are not known. The GAS cholesterol-dependent cytolysin, Streptolysin O (SLO), has well established cell and tissue destructive activity. We investigated the role of SLO in determining disease outcome in vivo, by using two different clinical lineages; the recently emerged hypervirulent outbreak emm type 32.2 strains, which result in sepsis, and the emm type 1.0 strains which cause septic arthritis. Using clinically relevant in vivo mouse models of sepsis and a novel septic arthritis model, we found that the amount and activity of SLO was vital in determining the course of infection. The emm type 32.2 strain produced large quantities of highly haemolytic SLO that resulted in rapid development of sepsis. By contrast, the reduced concentration and lower haemolytic activity of emm type 1.0 SLO led to translocation of bacteria from blood to joints. Importantly, sepsis associated strains that were attenuated by deletion or inhibition of SLO, then also translocated to the joint, confirming the key role of SLO in determining infection niche. Our findings demonstrate that SLO is key to in vivo phenotype and disease outcome. Careful consideration should be given to novel therapy or vaccination strategies that target SLO. Whilst neutralising SLO activity may reduce severe invasive disease, it has the potential to promote chronic inflammatory conditions such as septic arthritis.

scholarly journals Changes in epidemiologic characteristics and antimicrobial resistance of Streptococcus pyogenes isolated over 10 years from Japanese children with pharyngotonsillitis

2020 ◽  
Vol 69 (3) ◽  
pp. 443-450
Author(s):  
Kimiko Ubukata ◽  
Takeaki Wajima ◽  
Miyuki Morozumi ◽  
Megumi Sakuma ◽  
Takeshi Tajima ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Antibiotic Susceptibility ◽  
Rapid Identification ◽  
Specific Sequence ◽  
Content Type ◽  
Group A ◽  
Sequence Types ◽  
Identification And Characterization ◽  
Epidemiologic Characteristics

Introduction. Pharyngotonsillitis caused by Streptococcus pyogenes (group A streptococci, or GAS) is among the most common infections treated with antibiotics in pediatric patients. Aim. This study aimed to analyse changes in molecular epidemiology and antibiotic susceptibility among GAS isolates in three study periods spanning 10 years. Methodology. GAS isolated from paediatric patients with pharyngotonsillitis during Period I (mid-2007 to 2008, n=235), Period II (2012, n=210), and Period III (2018, n=189) were analysed for emm type, multilocus sequence type (MLST), antibiotic susceptibility, and macrolide (ML)- and quinolone (QL)-resistance genes. Results. Over 20 % of isolates represented emm1 and emm12 types, remaining common in all three periods. Among other emm types, emm4 was common in Period I, emm28 and emm89 in Period II, and emm3 and emm89 in Period III. All isolates remained highly susceptible to penicillins and cephalosporins. Isolates possessing mefA, ermA, or ermB genes mediating ML resistance increased from 34.9 % in Period I to 60.9 % in Period II, but fell to 27.5 % in Period III. QL-resistant isolates with amino acid substitutions affecting ParC and/or GyrA gradually increased from 11.5 to 14.3 %. Specific sequence types identified by MLST and emm typing were associated closely with ML or QL resistance. Conclusion. Our findings indicate that even in ambulatory care, antibiotic choice for these infections should be based on rapid identification and characterization of causative pathogens.

scholarly journals Molecular epidemiology of macrolide resistant Group A streptococci from Puducherry, India

2017 ◽  
Vol 11 (09) ◽  
pp. 679-683 ◽  
Author(s):  
Tintu Abraham ◽  
Sujatha Sistla
Keyword(s):  
Streptococcus Pyogenes ◽  
Macrolide Resistance ◽  
Streptococcal Infections ◽  
Genetic Determinants ◽  
Erythromycin Resistance ◽  
Group A ◽  
Macrolide Resistance Gene ◽  
Resistant Group ◽  
Resistant Strains ◽  
Resistance Rates

Introduction: In penicillin allergic patients, macrolides are the most commonly used antibiotics for treating streptococcal infections, irrespective of the higher resistance rates. The objective of this study was to evaluate the comparative prevalence, phenotypes, and genetic determinants of macrolide resistance and associated emm types among different clinical isolates of Streptococcus pyogenes. Methodology: A total of 173 Streptococcus pyogenes isolates were examined for macrolide resistance phenotype by double-disc test, resistance determinants by multiplex PCR and emm genotyping. Results: Erythromycin resistance was found in 51.4% of isolates, with MIC90 ≥ 256 µg/mL Inducible phenotype was commonly found (iMLS, 67.4%) followed by the M phenotype (32.5%). Among these isolates, 65.1% harboured ermB and 32.5% mefA as sole macrolide resistance gene, whereas presence of both, ermB plus mefA was observed in 2.2% cases. The most common types among resistant strains were emm63 (11.2%), emm44 (6.7%), emm42 (5.6%), and emm75.3, emm82, emm85, emm92, emm111.1 (4.4% each). Statistically significant association was observed between emm63, emm44 and erythromycin resistance (p ≤ 0.05). Association of these emm types and macrolide resistance have not been reported earlier. Conclusion: Higher macrolide resistance in this study can be attributed to overuse and misuse of this antibiotic. These findings indicate that macrolides should not be empirically used for treating severe streptococcal infections.

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