Molecular epidemiology of nonpharyngeal group A streptococci isolates in northern Lebanon

2020 ◽  
Vol 15 (16) ◽  
pp. 1555-1569
Author(s):  
Rayane Rafei ◽  
Malaik Hawli ◽  
Marwan Osman ◽  
Simon Khelissa ◽  
Tamara Salloum ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Antibiotic Susceptibility ◽  
Group A Streptococcus ◽  
Vaccine Coverage ◽  
Virulence Gene ◽  
Gene Profiling ◽  
Group A Streptococci ◽  
Structural Variability ◽  
Group A ◽  
Resistance Rates

Aim: To characterize the epidemiology of group A Streptococcus (GAS) involved in nonpharyngeal infections sparingly addressed in Lebanon. Materials & methods: A collection of 63 nonpharyngeal GAS isolates recovered between 2010 and 2019 from northern Lebanon were analyzed through emm typing, virulence gene profiling, FCT typing and antibiotic susceptibility analysis. Results & conclusion: A total of 29 emm subtypes was detected, with emm1 being the most dominant. A great intraclonal divergence driven by the loss and gain of superantigens or by the structural variability within the FCT regions was unraveled. The resistance rates for erythromycin and tetracycline were 8 and 20.6%, respectively. The 30-valent vaccine coverage was 76%. This study evidences the complexity of the neglected GAS pathogen in Lebanon.

scholarly journals Molecular Epidemiology of Group A Streptococcus Infections in The Gambia

Vaccines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 124
Author(s):  
Sona Jabang ◽  
Annette Erhart ◽  
Saffiatou Darboe ◽  
Aru-Kumba Baldeh ◽  
Valerie Delforge ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Vaccine Development ◽  
Group A Streptococcus ◽  
Epidemiological Data ◽  
The Gambia ◽  
Strain Diversity ◽  
Group A ◽  
Considerable Strain

Molecular epidemiological data on Group A Streptococcus (GAS) infection in Africa is scarce. We characterized the emm-types and emm-clusters of 433 stored clinical GAS isolates from The Gambia collected between 2004 and 2018. To reduce the potential for strain mistyping, we used a newly published primer for emm-typing. There was considerable strain diversity, highlighting the need for vaccine development offering broad strain protection.

Electron microscopy of the replicative events of A25 bacteriophages in group A streptococci

1972 ◽  
Vol 18 (1) ◽  
pp. 93-96 ◽  
Author(s):  
S. E. Read ◽  
R. W. Reed
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Electron Microscope ◽  
Nucleic Acid ◽  
Group A Streptococcus ◽  
Group A Streptococci ◽  
Virulent Phage ◽  
Acid Pool ◽  
Group A ◽  
A Cell

The replicative events of a virulent phage (A25) infection of a group A Streptococcus (T253) were studied using the electron microscope. The first intracellular evidence of phage replication in a cell occurred 30 min after infection with arrest of cell division and increase in the nucleic acid pool. Phage heads were evident in the nucleic acid pool of the cells 45 min after infection. Release of phages occurred by splitting of the cell wall along discrete lines. This appeared to be at sites of active wall synthesis, i.e., near the region of septum formation. Many phage components were released but relatively few complete phages indicating a relatively inefficient replicative system.

scholarly journals Value of rapid test for identification of beta hemolytic Streptococcus antigens in children with Streptococcal pharyngitis

2004 ◽  
Vol 132 (suppl. 1) ◽  
pp. 39-41 ◽  
Author(s):  
Branimir Nestorovic ◽  
Suzana Laban-Nestorovic ◽  
Veselinka Paripovic ◽  
Katarina Milosevic
Keyword(s):  
Group A Streptococcus ◽  
Rapid Test ◽  
Streptococcal Pharyngitis ◽  
Early Spring ◽  
Group A Streptococci ◽  
Upper Respiratory Tract ◽  
Isolation And Identification ◽  
Cervical Lymph Nodes ◽  
Group A ◽  
Tract Infections

Beta-hemolytic group A streptococcus (Streptococcus pyogenes) is the most common bacterial agent associated with the upper respiratory tract infections in humans. The most frequently group A streptococcus-associated disease is pharyngitis. Males and females are equally affected by group A streptococcus. There is seasonal increase in the prevalence of group A streptococcus-associated pharyngitis. Streptococcal pharyngitis is most prevalent in winter and early spring with higher incidence of disease observed in crowded population such as school children. Early diagnosis and treatment of group A streptococcal pharyngitis has been shown to reduce the severity of symptoms and further complications such as rheumatic fever and glomerulonephritis. The conventional methods used for identification of group A streptococci depend on isolation and identification of the organism on blood agar plates. These methods usually require 18-24 hours of incubation at 37?C. Such delay in identifying the group A streptococcus has often made physicians to administer therapy without first disclosing the etiological agent. Development of immunologic tests, capable of detecting the group A streptococcal antigen directly from the throat swabs, produced rapid test results employed for better treatment of patients. STREP A test is a rapid immunochromatographic test for the detection of group A streptococci from throat swabs or culture. The accuracy of the test does not depend on the organism viability. Instead, group A strep antigen is extracted directly from the swab and identified using antibodies specific for the group A carbohydrates. We compared rapid test with conventional throat swab in 40 children, who met Centor criteria for streptococcal pharyngitis (absence of cough, high fever, purulent pharyngitis, enlarged and painful cervical lymph nodes). Overall congruence of rapid test and culture was 94%. Test is easy to perform and it is recommended as the first diagnostic test for management of children with streptococcal pharyngitis. In children with negative test, but with characteristics highly suggestive of streptococcal infection, throat culture should be performed.

scholarly journals Molecular epidemiology and antimicrobial resistance of group A streptococcus recovered from patients in Beijing, China

2020 ◽  
Author(s):  
Hongxin Li ◽  
Lin Zhou ◽  
Yong Zhao ◽  
Lijuan Ma ◽  
Xiaoyan Liu ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Group A Streptococcus ◽  
Resistance Rate ◽  
Gene Profiling ◽  
Epidemiological Surveillance ◽  
Erythromycin Resistance ◽  
Children's Hospital ◽  
Children’S Hospital ◽  
Group A ◽  
Epidemiological Characteristics

Abstract Background: Group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern. The objective of this study was to investigate the molecular epidemiological characteristics and antimicrobial resistance of GAS isolates from patients in Children’s Hospital in Beijing. Methods: From 2016 to 2017, pharyngeal swab samples were collected from the outpatients in Children’s Hospital, Capital Institute of Pediatrics, who were diagnosed with scarlet fever. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes ( ermB, ermA, mefA ), emm (M protein-coding gene) typing, and superantigens (SAg) gene profiling were examined by polymerase chain reaction (PCR). Results: A total of 297 GAS isolates were collected. The susceptibility of the isolates to penicillin, ceftriaxone, and levofloxacin was 100%. The resistance rate to erythromycin and clindamycin was 98.3% and 96.6%, respectively. The dominant emm types were emm12 (65.32%), emm1 (27.61%), emm75 (2.69%), and emm89 (1.35%). Of the 297 isolates, 290 (97.64%) carried the ermB gene, and 5 (1.68%) carried the mefA gene, while none carried the ermA gene. The most common superantigen genes identified from GAS isolates were smeZ (96.97%) , speC (92.59%), speG (91.58%), ssa (85.52%), speI (54.55%), speH (52.19%), and speA (34.34%). Isolates with the genotype emm1 possessed speA , speC , speG , speJ , speM , ssa , and smeZ , while emm12 possessed speC , speG , speH , speI , speM , ssa , and smeZ superantigens. Conclusions: The prevalent strain of GAS isolates in Beijing has a high resistance rate to macrolides; however, penicillin can still be the preferred antibiotic for treatment. Erythromycin resistance was predominantly mediated by ermB. The common emm types were emm12 and emm1. There was a correlation between emm and the superantigen gene. Thus, long-term monitoring and investigation of the emm types and superantigen genes of GAS prevalence are imperative.

Molecular epidemiology of group A streptococcus causing scarlet fever in northern Taiwan, 2001–2002

2007 ◽  
Vol 58 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Ying-Yan Chen ◽  
Chung-Ter Huang ◽  
Shu-Man Yao ◽  
Yi-Ching Chang ◽  
Pei-Wun Shen ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Scarlet Fever ◽  
Group A Streptococcus ◽  
Group A ◽  
Northern Taiwan

scholarly journals Epidemiological analysis of group A streptococci recovered from patients in China

2006 ◽  
Vol 55 (8) ◽  
pp. 1101-1107 ◽  
Author(s):  
Hong-bo Jing ◽  
Boa-an Ning ◽  
Huai-jie Hao ◽  
Yu-ling Zheng ◽  
Dong Chang ◽  
...  
Keyword(s):  
Virulence Genes ◽  
Vaccine Development ◽  
Mainland China ◽  
Virulence Gene ◽  
Start Codon ◽  
Antimicrobial Susceptibility Tests ◽  
Group A ◽  
Susceptibility Tests ◽  
Species Specific ◽  
Resistance Rates

Since the mid-1980s, there has been a resurgence of severe forms of invasive group A streptococcal (GAS) disease in many countries and regions. However, there has not been any systemic epidemiologic analysis of GAS disease reported in mainland China. To analyse the molecular epidemiology of GAS disease, 86 strains from patients in different regions of mainland China were collected. The collection sites included blood, pus, wounds, the epipharynx and other sites. A total of 21 different emm types were identified in the isolates. In both invasive and non-invasive isolates, M1 (29.1 %) and M12 (23.3 %) were the most prevalent types, a different distribution to M type distributions reported in other countries. Furthermore, minor emm gene sequence alterations were noted for six types. Several important GAS virulence factors were detected by PCR using specific primers. The speB and slo genes were detected in all isolates and were species specific. Four superantigen genes, speA, speC, smeZ and ssa, were found in 52 % (45/86), 51 % (44/86), 82 % (71/86) and 23 % (27/86) of isolates, respectively. M1 isolates harboured more speA (84 %) and fewer speC genes (44 %), while M12 isolates had fewer speA (35 %) and more speC genes (100 %). There was also an association between some virulence genes and isolation sites, perhaps due to the correlation between the emm type distribution and virulence gene occurrence. For two important virulence genes related to necrotizing fasciitis, the sil gene was only carried by 11 of 86 isolates, and no sil gene contained the start codon ATA. The sla gene rarely occurred in GAS isolates, only four of 86 GAS strains being positive, including two isolates obtained from blood. In antimicrobial susceptibility tests, the overall rate of drug resistance in GAS isolates was higher than reported rates in other countries, and the resistance rates to erythromycin, tetracycline and clindamycin were 91.8, 93.4 and 80 %, respectively. This epidemiological study may help to understand the pathogenesis of GAS disease and aid in vaccine development.

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