Lancefield Grouping Research Articles

Coinfection by Group C Streptococcus dysgalactiae subsp. equisimilis and Flavobacterium davisii in Nile Tilapia from the United States

Streptococcal disease and columnaris disease are common in tilapia aquaculture across the globe. Coinfections are also common but often overlooked or not reported. In the present study, we describe the clinical presentation of streptococcosis and columnaris coinfection in diseased Nile tilapia (Oreochromis niloticus), and the phenotypic (Lancefield grouping, hemolytic pattern, biochemical characteristics, antibiotic susceptibility) and genotypic (multilocus sequence analysis for streptococci and multiplex PCR for flavobacteria) characterisation of its etiological agents, namely Group C Streptococcus dysgalactiae subsp. equisimilis and Flavobacterium davisii. We further fulfilled Koch’s postulates with the S. dysgalactiae subsp. equisimilis isolate in genetically improved Nile tilapia.

STREPTOCOCCUS SPP. AS ETIOLOGICAL AGENT OF SUBCLINICAL AND CLINICAL MASTITIS OF DAIRY COWS IN REPUBLIC OF BULGARIA

The aim of this study was to determine the species composition of streptococci causing subclinical, and clinical mastitis in dairy cows, their prevalence and antimicrobial drug sensitivity with respect to appropriate therapy. The study subject was the involvement and prevalence of bacteria from the genus Streptococcus in the etiology of subclinical, and clinical mastitis in dairy cows. The survey was conducted in eight cattle farms from different regions in Bulgaria in 2020 and 2021. After clinical examination and rapid mastitis test, a total of 239 cows were diagnosed with udder inflammation - 34 (14.2%) with clinical signs and 205 (85.8%) with subclinical mastitis. Laboratory analyses were performed on 346 samples. Two hundred and seventy two bacterial strains were isolated, and 151 (55.5%) were determined to belong to Streptococcus spp. Lancefield grouping and species identification of haemolytic variants was done. It was found out that in subclinical forms of mastitis, 54.5% of isolates belonged to Streptococcus spp., respectively 63.3 % of isolates in clinical forms of mastitis also belonged to Streptococcus spp. Out of them, 38.6% were S. uberis, 35.6% were identified as S. agalactiae and 25.8% − as S. dysgalactiae. In vitro tests of the sensitivity to antimicrobial drugs from various groups and classes were conducted with all field isolates. The tests demonstrated a relatively well-preserved sensitivity to antimicrobial agents with the exception of tetracycline

Serotyping of invasive and colonizing group B Streptococcus (GBS) isolates at selected hospitals in Sri Lanka: a multicenter study.

Group B Streptococcus (GBS) causes significant morbidity and mortality in neonates, pregnant women and patients with underlying comorbidities. Intrapartum antibiotic prophylaxis (IAP) is currently the mainstay of prevention and effective vaccine against invasive GBS disease is under clinical trial. To describe the serotype distribution of invasive and colonizing GBS isolates in Sri Lanka. Probable GBS isolates from high vaginal swabs (HVS) and sterile body sites were collected from eight selected hospital laboratories. Following confirmation of the identification as group B Streptococcus by phenotypic methods including Lancefield grouping test (Plasmatic UK), isolates were tested for serotyping by latex agglutination test kit (STATEN serum institute, Denmark). Out of the 145 probable GBS isolates only 100 from HVS and 37 from sterile body sites were confirmed as GBS. Serotype III was the most predominant in invasive GBS isolates followed by Ia, Ib, VI, II and V in the descending order of frequency. Serotype VI was the most predominant in HVS isolates followed by serotype III, V, Ia, II, Ib and IV. Difference of GBS serotype distribution between the invasive and HVS group was statistically significant (P value = 0.038). Serotype distribution pattern of the study isolates was comparable to most of the other developing and developed countries and hence will be beneficial in future vaccine introduction. GBS vaccine which is currently under clinical trial (Ia, Ib and III) is potentially effective for preventing 68% of the early onset disease in neonates in this study setting.

Prevalence and the risk factors for the carriage of beta-haemolytic streptococci among women visiting a tertiary care hospital in South India

Streptococci are gram positive cocci arranged in chains and are part of normal flora of humans and animals. The present study is carried out to determine the prevalence and risk factors for the carriage of beta-haemolytic streptococci (BHS) among women visiting Dr. VRK Women’s Teaching Hospital & Research Centre, Hyderabad. Vaginal swabs were collected from 250 patients attending outpatient department (OPD) of Dr. VRK Women’s Teaching hospital. Swabs were inoculated onto 5% sheep blood agar plates and incubated for 24 h at 37°C in a candle jar. BHS isolates were phenotypically identified by standard microbiological techniques, all the isolates presumptively identified as BHS were tested for Bacitracin susceptibility. Sensitive isolates were presumptively identified as GAS and resistant isolates were identified as non-group A BHS (NGABHS). Presumptively identified GAS & NGABHS isolates were serogrouped by Lancefield grouping using a commercially available latex agglutination test. BHS were isolated from 12.4% of samples. As many as 12 BHS isolates were identified as GAS and 19 were identified as NGABHS. Ten of nineteen were identified as group B (GBS), 4 (12.9%) were identified as group C (GCS) and 5 (16.12%) were identified as group G (GGS). Among six clinical groups, the prevalence of GAS is highest i.e. 7.5% in female patients visiting Gynaecology OPD with history of white discharge. Prevalence of NGABHS was more among post insertion (18%) IUCD group compared to pre insertion (8%) IUCD group. GBS were isolated from 7% of samples from IUCD group and 4% of samples from prostitutes.This study reports the prevalence of BHS among women visiting a tertiary care hospital in Hyderabad. This study also identified certain risk factors such as IUCD usage and working as a FSW are associated with the increased prevalence of NGABHS especially GBS.

Prevalence and antibiotic susceptibility of Streptococcus pyogenes isolated from pyoderma in a tertiary care hospital, Hyderabad, South India

Pyoderma is a common acute superficial bacterial skin infection which is highly contagious. In the great majority of cases, pyoderma is caused by , , or both. The present study was carried out to determine the prevalence and antibiotic susceptibility of isolated from pyoderma in Dr. VRK Women’s Teaching hospital.Swabs or pus samples were collected from 250 patients attending Dermatology, outpatient department (OPD) of Dr. VRK Women’s Teaching hospital. Samples were inoculated onto 5% sheep blood agar plates and incubated for 24 h at 37°C in a candle jar. BHS isolates were phenotypically identified by standard microbiological techniques, all the isolates presumptively identified as BHS were tested for Bacitracin susceptibility. Presumptive identification of a strain as a Group A Streptococcus (GAS) was also made by PYRase test. Presumptively identified GAS isolates were serogrouped by Lancefield grouping using a commercially available latex agglutination test. isolates were subjected to antimicrobial susceptibility testing by Kirby-Bauer disc diffusion method.BHS were isolated from 30% of samples. Prevalence of BHS was more among 0-10 years age group (38%). BHS were isolated more frequently from males (38.8%). were isolated from 52 (20.8%) samples. All 52 isolates were found to be susceptible to Penicillin G, amoxicillin, ceftriaxone, azithromycin and vancomycin. Erythromycin and clindamycin showed good activity with sensitivity rates of 92.3% & 96.1%, respectively. Resistance to tetracycline (59.6%) and chloramphenicol (23.1%) was commonly seen in .This study reports the prevalence and antibiotic susceptibility of isolated from pyoderma in Dr. VRK Women’s Teaching hospital. Results of this study suggests the peak incidence of pyoderma in children aged 0 to 10 years and male preponderance. Our study also reports high prevalence of tetracycline and chloramphenicol resistance in .

Group B Streptococcal Colonisation among Pregnant Women Attending a Tertiary Care Hospital of Northeast India

Introduction: Group B Streptococcus (GBS) is an important cause of maternal as well as neonatal morbidity and mortality worldwide. Early identification of colonisation of GBS among pregnant women plays an important role in preventing neonatal disease by taking measures such as antibiotic prophylaxis. In India, the spectrum of disease caused due to GBS is largely unrecognised due to lack of screening practices and also there is no specific guideline to prevent the disease. Aim: To determine the group B streptococcal colonisation and their antibiotic susceptibility profile among pregnant women of North-east India. Materials and Methods: The study was a hospital based cross- sectional survey conducted from April to June 2019. A total of 295 pregnant women with gestational age more than 35 weeks attending the Outpatient and Inpatient Departments were included in the study. Two vaginal swabs and two rectal swabs were collected from each participant and were processed according to standard laboratory protocol. Identification of GBS was done on the basis of Christie-Atkins-Munch-Peterson (CAMP) test and Lancefield grouping by latex agglutination test. Antibiotic susceptibility profile was also obtained for these isolates for certain antibiotics. Chi-square test was applied to determine the association of isolation among different types of cases. Results: Out of 295 pregnant women, 15(5.1%) showed GBS colonisation. There was no significant association found with age or socioeconomic status. However, GBS colonisation was found to be significantly associated with increasing gravidity (p-value=0.03). GBS colonisation of vaginal flora is siginficantly associated with rectal colonisation (p-value <0.01). Although certain isolates were found to be resistant to macrolide antibiotics (66.7%), all strains were uniformly sensitive (100%) to penicillin, levofloxacin, quinupristin-dalfopristin, vancomycin and linezolid. Conclusion: A low rate of colonisation was determined among the pregnant women and it is not associated with age and socioeconomic status. However, it is suggested that routine screening of pregnant women especially multigravida women should be done to prevent the transmission to the newborn.

Streptococcal Throat Carriage among Primary School Children Living in Uyo, Southern Nigeria

AbstractSurveillance of the carrier state for β-hemolytic streptococcal (BHS) throat infections remains essential for disease control. Recent published works from Sub-Saharan Africa have suggested a changing epidemiology in the burden of BHS throat infections. The objective of the present study was therefore to determine the prevalence and pattern of BHS throat carriage in school-aged children in Uyo, Akwa Ibom State. This was a prospective cross-sectional study of 276 primary school children in Uyo. Subjects were recruited by multistage random sampling. Obtained throat swabs were cultured on 5% sheep blood agar. Lancefield grouping on positive cultures was done by using the Oxoid Streptococcal Grouping Latex Agglutination Kit, United Kingdom. Antimicrobial susceptibility testing was done with the disk diffusion method. Associations were tested with Fischer's exact test. The prevalence of BHS carriage was 3.3%. Group C Streptococcus was identified in 89% of isolates and Group G Streptococcus in 11%. Younger age and larger household size were associated with asymptomatic streptococcal throat infections. Antimicrobial susceptibility was highest with cefuroxime and clindamycin (89% of isolates each), while 78% of isolates were susceptible to penicillin. None of the tested isolates was susceptible to co-trimoxazole. The prevalence of streptococcal throat carriage in the study area was low. There were no Group A Streptococcus isolates suggesting an evolving epidemiology of BHS disease in the study area.

Assessment of Group a Streptococcus and Antimicrobial Resistance Pattern in School Going Children in Morang District, Nepal

Introduction: Group A hemolytic Streptococcal infections has worldwide distribution among children and it poses an important problem globally. There is lack of baseline information regarding Group A hemolytic streptococci in school going children in the eastern part of Nepal.
 Objective: The study was conducted for assessing the carrier rate of Group A hemolytic streptococci in school going children in eastern part of Nepal.
 Methodology: This study was community based cross-sectional study. During the study of 9 months, a total of 518 patients (school-going children) from different school who were symptomatic as well as asymptomatic were enrolled. All samples were collected by rubbing quickly and thoroughly over either tonsils (or tonsillar fossa) and over the posterior wall of the pharynx using light pressure and were subjected to microbial analysis in the clinical Microbiology Laboratory. The specimens were inoculated immediately into Blood agar (BA) and MacConkey agar (MA) and were incubated at 37°C aerobically and were checked for growth after overnight incubation. The identification of bacterial isolates was carried out by Clinical and Laboratory Standards Institute (CLSI) guidelines with colonial morphology and staining reactions. Biochemical tests such as catalase, bacitracin sensitivity test (0.004 units) and Lancefield grouping (PastorexTM Strep) were performed. All the identified S. pyogenes isolates thus obtained were subjected to in vitro antibiotics sensitivity testing by using Kirby-Bauer disc- diffusion method as recommended by CLSI (2014).
 Results: During 9 months period total 518 throat swabs (303 male and 215 female)from school going children attending government and private school were collected after taking verbal consent and were cultured on blood agar and MacConkey agar.Streptococcus pyogenes was identified by using standard microbiological procedures. Antimicrobial susceptibility testing of the isolates was performed by Kirby Bauer disc diffusion method. Group A streptococci (GAS) was isolated from 28 (5.4%) school going children, of which 15 (5%) were male and 13 (7%) were female. There was no significant sex difference in colonization of GAS (p>0.05). Majority of cases were asymptomatic. In this study it was observed that the sensitive drugs for GAS were Penicillin and their deravatives (100%), Ciproflocaxin (100%) and Azithromycin (100%) followed by Erythromycin (75%) and Cotrimoxazole (71.4%) (Table 9,10).
 Conclusion: The present preliminary study provides the base-line information on the GAS carriage rate and resistance trend among healthy school children. The present study showed that Penicillin and its derivatives should be used to treat a case of GAS pharyngitis and Azithromycin for those who are allergic to Penicillin. The present study also showed that Staphylococcus aureus as an equally important agent of pharyngitis and hence throat swab culture should be requested for appropriate therapy.

Prevalence and pattern of beta-haemolytic streptococcal throat infections among primary school children in a rural community in rivers state

Background: Group A beta-haemolytic Streptococcus (GABHS) remains a major cause of morbidity and mortality in humans where it causes symptomatic pharyngitis and the non-suppurative sequelae of acute rheumatic fever and post-streptococcal acute glomerulonephritis. Regional evaluation of streptococcal throat infections may be helpful in disease surveillance. The aim of this study was to evaluate the prevalence and pattern of GABHS throat infections among primary school children in a rural community in Rivers State, Nigeria. Methodology: This cross-sectional study was carried out between May and July 2015 in Emohua local government area of Rivers State, Nigeria. Pupils were recruited using a multistaged random sampling technique. Throat swabs obtained were cultured using sheep blood and sent for microscopy and Lancefield grouping. Results: A total of 456 pupils aged 6–12 years were recruited, of which 54 (11.8%) had a positive throat culture of beta-haemolytic Streptococcus (BHS). The isolates were Lancefield Groups B (23; 42.6%), A (18; 33.3%), D (9; 19.6%), C (3; 5.6%) and F (1; 1.8%). No Group G BHS was isolated. Age, sex, socioeconomic class, classroom and household overcrowding did not significantly influence the prevalence of BHS throat infections. Conclusion: The prevalence of BHS throat infections in this rural community was similar to that in the urban areas in Nigeria. There was no significant difference between the prevalence of BHS in symptomatic and asymptomatic pupils.

Prevalence, Clinical Features and Antibiotic Susceptibility of Group A Streptococcal Skin Infections in School Children in Urban Western and Northern Uganda.

Group A Streptococcus (GAS) skin infections can lead to invasive sepsis, poststreptococcal glomerulonephritis, and potentially rheumatic heart disease (RHD). Within a study to identify predisposing factors of RHD in Ugandan schoolchildren, we determined the prevalence of skin infections and assessed the clinical features and antibiotic susceptibility of GAS skin infection. Cross-sectional study conducted at 3 urban primary schools in Western and Northern Uganda in March 2017. A dermatologist rendered clinical diagnoses and obtained a skin swab specimen from lesions with signs of bacterial infection. Beta-hemolytic colonies underwent Lancefield grouping, species identification by polymerase chain reaction and antimicrobial susceptibility testing. From 3265 schoolchildren, we observed 32% with ≥1 fungal, 1.8% with ≥1 bacterial, 0.9% with ≥1 viral, and 0.2% with ≥1 ectoparasitic infection. Of 79, 25 (32%) specimens were GAS-positive, of which one-third demonstrated tetracycline resistance. Of 17 impetigo cases, 13 (76%) were located on the leg/foot and 3 (18%) on the head/neck. Prevalence of GAS skin infection was 0.8% (25 of 3265). In Northern Uganda, where subclinical definite RHD prevalence is 1.1%, GAS skin infection prevalence was 1.2% (4 of 343) and 0.9% (3 of 352). This study identifies tetracycline-resistant GAS in Ugandan communities, suggests modified skin examination of exposed anatomic locations may be appropriate for population-based GAS skin infection studies, and underscores need for clear case definitions of GAS skin infection. Future studies are needed to evaluate the role of GAS skin infection in development of RHD in Ugandan communities.

Streptococcal toxic shock syndrome caused by β-hemolytic streptococci: Clinical features and cytokine and chemokine analyses of 15 cases

Objectivesβ-Hemolytic streptococci occasionally cause severe infections such as necrotizing fasciitis and streptococcal toxic shock syndrome (STSS). Here, we conducted a prospective study to investigate the production of cytokines and chemokines in patients with STSS to explore its pathogenesis in survivors and fatal cases. MethodsFrom January 2013 through August 2015, all culture results from normally sterile sites were prospectively followed and screened for STSS. Clinical characteristics of the patients with STSS were evaluated and compared between survivors and fatal cases. Serum samples were collected on admission for quantification of various cytokines and chemokines. Bacterial strains were categorized by Lancefield grouping and analyzed for the emm type, and presence of speA, speB, speC, and speF. ResultsFifteen patients received diagnosis of STSS. The median age of the patients was 60-year-old, and the mortality rate was 40% despite intensive treatment. Nine strains were categorized as group A, two belonged to group G, and four to group B. Group A contained various emm genotypes. Unexpectedly, potent proinflammatory cytokine levels such as TNF-α and IL-1β were not significantly elevated, and comparison with surviving patients showed that IL-6, IL-8, and MCP-1 levels were significantly decreased and creatine kinase level was significantly elevated in fatally ill cases. ConclusionOur results indicate that reduced production of proinflammatory cytokines and chemokines may be involved in STSS pathogenesis and critical for prognosis of patients with STSS.

The Relationship between Different Types of Streptococci and Pharyngotonsillitis: A Systematic Review

Introduction: Streptococci were initially viewed by Louis Pasteur in 1879. Brown, in 1919, created the first systematized classification of streptococci in α, β and γ. Rebecca Lancefield contributed for knowledge of streptococcal polysaccharides discovering groups and M cell wall protein. Streptococci are gram positive, catalase and oxidase negative. Streptococci related to pathogenesis of acute sore throat are Streptococcus β-hemolytic of the groups A, B, C, F and G. Objective: Our objective was to make a review of the different types of streptococcus that can cause infection in the oropharynx. Review: Streptococcus pyogenes is belonging to the Lancefield grouping. Skin and mucous membranes of humans are the only known reservoir in the nature of streptococcus group A. Streptococcus of Group B (SGB) was originally isolated by Nocard in 1887. The primary habitat of these bacteria is the human colon, although it may colonize the oropharynx and especially, the vagina. For this reason, in mid-1960, the SGB has become a major cause of perinatal bacterial infection, including bacteremia and urinary tract infection in pregnant women. Group C is involved in purulent pharyngitis outbreaks. According to Fox et al, Streptococcus anginosus is the most common isolate β-hemolytic group C in the oropharynx. Streptococcus Group C (SGC) is reported as “pyogenes-like” because it shares important virulence factors such as hemolysins, extracellular enzymes and M proteins as well as the SGA. Conclusion: We conclude that it’s important to have knowledge about the different types of streptococci to better treat patients with sore throats and problems associated with this condition.

Identification of Streptococcus pyogenes - Phenotypic Tests vs Molecular Assay (spy1258PCR): A Comparative Study.

Traditionally Group A Streptococcus pyogenes (GAS) is differentiated from other beta haemolytic streptococci (BHS) by certain presumptive tests such as bacitracin sensitivity and production of Pyrollidonyl Aryl Sulfatase (PYR). The phenotypic and genotypic confirmatory tests are Lancefield grouping for cell wall carbohydrate antigen and PCR for spy1258 gene respectively. Reliance on presumptive tests alone may lead to misidentification of isolates. To compare the predictive values of routine phenotypic tests with spy1258 PCR for the identification of Streptococcus pyogenes. This comparative analytical study was carried out in the Department of Microbiology, JIPMER, Puducherry, over a period of 18 months (1(st) November 2013 to 30(th) April 2015). Two hundred and six consecutive BHS isolates from various clinical samples were subjected to phenotypic tests such as bacitracin sensitivity, PYR test and Lancefield grouping. The results were compared with spy1258 PCR which was considered 95 the confirmatory test for identification. The sensitivity and specificity of phenotypic tests were as follows; Susceptibility to bacitracin - 95.42%, 70.96%, PYR test - 95.42%, 77.41%, Lancefield grouping- 97.71%, 80.64%. Clinical laboratories should not depend on bacitracin sensitivity as a single presumptive test for the routine identification of GAS but should use supplemental tests such as PYR test or latex agglutination test and for best results use spy1258 PCR.

Preventing invasive Group B Streptococcus (GBS) disease in South African infants: Time for change

Streptococcus agalactiae is an encapsulated Gram-positive coccus that colonises the gastrointestinal and genitourinary tracts. This organism belongs exclusively to Group B in Lancefield's grouping of Streptococcus species and therefore is referred to as Group B Streptococcus (GBS). Of the ten known serotypes, serotypes Ia and III account for most disease. The greatest burden of invasive GBS disease is seen in infants <3 months of age, although GBS can cause disease in adults and pregnant women. Disease manifesting in the first 6 days of life is referred to as early-onset disease (EOD), whereas late-onset disease (LOD) manifests from day 7 - 89 of life.

Prevalence of group A streptococcal pharyngitis among schoolchildren of Barabanki district, Uttar Pradesh, India

Background: The aim of this study was to determine the prevalence of Group A streptococcus (GAS) pharyngitis and its carriage among schoolchildren in the age group 5-15 years in Barabanki district, Uttar Pradesh, India. The study also aimed to determine the minimum inhibitory concentration (MIC) of Penicillin G, antimicrobial susceptibility pattern and inducible Clindamycin resistance in GAS. Materials and Methods: Three hundred schoolchildren from six different schools were included in the study. Identification of group A streptococcus was done on the basis of Bacitracin sensitivity test, pyrrolidonyl peptidase (PYRase) test and Lancefield grouping by latex agglutination test. Antibiotic susceptibility test and D-zone test were done in GAS isolates. Results: Out of the 300 schoolchildren, GAS was found in three (4.7%) out of 63 symptomatic children and two (0.8%) out of 237 asymptomatic children. The overall prevalence of GAS pharyngitis and of GAS carriage was 1% and 0.67%, respectively. The isolation of GAS was significantly higher in symptomatic cases when compared to asymptomatic cases (P value = 0.0308). All the strains were sensitive to Penicillin, Ampicillin, Quinupristin-Dalfopristin, Vancomycin and Linezolid. Conclusion: A low prevalence of GAS pharyngitis and GAS carriage was observed in the study, probably due to the cross-sectional nature of the study. All five GAS isolates were sensitive to Penicillin.

Characterization ofStreptococcus milleriGroup Isolates from Expectorated Sputum of Adult Patients with Cystic Fibrosis

With the recent insights into the Streptococcus milleri group (SMG) as pulmonary pathogens in patients with cystic fibrosis (CF), we sought to characterize 128 isolates from the sputum of adults with CF, along with 45 isolates from patients with invasive diseases for comparison. The tests performed included Lancefield grouping; tests for hemolysis; tests for the production of hyaluronidase, chondroitin sulfatase, DNase, proteases, and hydrogen peroxide; and PCR for the detection of the intermedilysin gene (ily). We also generated biochemical profiles with the Rapid ID Strep 32 API system and tested cell-free supernatants for the presence of the signal molecule autoinducer-2 (AI-2) using a Vibrio harveyi bioassay with a subset of CF strains. The S. intermedius isolates from both strain collections were similar, while the S. constellatus and S. anginosus isolates yielded several biotypes that differed in prevalence between the two strain collections. Beta-hemolytic, Lancefield group C S. constellatus comprised 74.4% of the S. constellatus isolates from patients with CF but only 13.3% of the corresponding isolates from patients with invasive infections. This was the only S. constellatus biotype associated with pulmonary exacerbations. Hyaluronidase-positive S. anginosus was detected only among the isolates from patients with CF. Strain-to-strain variability in AI-2 expression was evident, with the mean values being the highest for S. anginosus, followed by S. constellatus and then S. intermedius. Cluster analysis and 16S rRNA sequencing revealed that the species of SMG could be accurately determined with a minimum of three phenotypic tests: tests for the Lancefield group, hyaluronidase production, and chondroitin sulfatase production. Furthermore, isolates from patients with invasive infections clustered with isolates from the sputum of patients with CF, suggesting that the respiratory tract isolates were equally pathogenic.

ISOLATION AND IDENTIFICATION OF MUTAN'S STREPTOCOCCI BACTERIA FROM HUMAN DENTAL PLAQUE SAMPLES

Fifty plaque samples were collected from teeth. Forty five samples were considered to be positive bacterial isolates about (10 4 bacteria/ml) using selective Ms-agar (Mitis-Salivarius agar) medium. Thirty isolates were considered to be related to the genus Streptococcus and specially to the mutans streptococci of various group; S. sobrinus (serotype D, G), S. mutans (serotype C, F), S. cricetus (serotype A) and S. rattus (serotype B) with percentages of (39.29%), (30.30%), (18.18%) and (3.03%), respectively depending on biochemical and Lancefield grouping identification systems.

Streptococcus sinensis may react with Lancefield group F antiserum

Lancefield group F streptococci have been found almost exclusively as members of the 'Streptococcus milleri' group, although they have been reported very occasionally in some other streptococcal species. Among 302 patients with bacteraemia caused by viridans streptococci over a 6-year period, three cases were caused by Streptococcus sinensis (type strain HKU4T, HKU5 and HKU6). All three patients had infective endocarditis complicating their underlying chronic rheumatic heart diseases. Gene sequencing showed no base differences between the 16S rRNA gene sequences of HKU5 and HKU6 and that of HKU4T. All three strains were Gram-positive, non-spore-forming cocci arranged in chains. All grew on sheep blood agar as alpha-haemolytic, grey colonies of 0.5-1 mm in diameter after 24 h incubation at 37 degrees C in ambient air. Lancefield grouping revealed that HKU5 and HKU6 were Lancefield group F, but HKU4T was non-groupable with Lancefield groups A, B, C, D, F or G antisera. HKU4T was identified by the Vitek system (GPI), API system (20 STREP) and ATB system (ID32 STREP) as 99 % Streptococcus intermedius, 51.3 % S. intermedius and 99.9 % Streptococcus anginosus, respectively. Using the same tests, HKU5 was identified as 87 % Streptococcus sanguinis/Streptococcus gordonii, 59 % Streptococcus salivarius and 99.6 % S. anginosus, respectively, and HKU6 as 87 % S. sanguinis/S. gordonii, 77 % Streptococcus pneumoniae and 98.3 % S. anginosus, respectively. The present data revealed that a proportion of Lancefield group F streptococci could be S. sinensis. Lancefield group F streptococci should not be automatically reported as 'S. milleri'.

The role of group C and group G streptococci in acute pharyngitis in children.

Group C streptococci (GCS) and group G beta-haemolytic streptococci (GGS) have caused well-documented epidemics of acute pharyngitis in children, but the importance of these organisms in causing endemic or sporadic pharyngitis is uncertain. The heterogeneity of GCS and GGS may obscure the role of certain subtypes, such as the large-colony-forming strains of group C (Streptococcus dysgalactiae subsp. equisimilis) or group G, in endemic pharyngitis. For a 1-year period, children (aged 6 months to 18 years) (n = 2085) who presented with pharyngitis to the children's hospital emergency department and two outpatient offices were enrolled in a cross-sectional study to ascertain the role of large-colony-forming GCS and GGS in acute pharyngitis. Control patients (n = 194) were children who presented to the same locations during the same time period with non-respiratory tract symptoms or to the orthopaedic cast clinic. Throat cultures were obtained by a standard reference method, and swabs were plated on Strep-Selective Agar. Lancefield grouping and species identification was performed on all beta-haemolytic isolates. In total, 65 (3%) large-colony-forming GCS and GGS strains were obtained from pharyngitis patients, and three (1.5%) were obtained from the control group (odds ratio 2.0; 95% confidence interval 0.6-6.1). The low isolation rate of large-colony-forming strains of GCS and GGS indicates that even if these organisms are associated with acute, sporadic pharyngitis in paediatric patients, they represent an unusual pathogen.

MP021 Superantigen like gene in human pathogenic Streptococcus dysgalactiae, subsp. equisimilis: Recombinant expression and characterisation of putative streptococcal pyrogenic exotoxin G (SPEGdys)

Group C streptococci (GCS) and group G β-haemolytic streptococci (GGS) have caused well-documented epidemics of acute pharyngitis in children, but the importance of these organisms in causing endemic or sporadic pharyngitis is uncertain. The heterogeneity of GCS and GGS may obscure the role of certain subtypes, such as the large-colony-forming strains of group C (Streptococcus dysgalactiae subsp. equisimilis) or group G, in endemic pharyngitis. For a 1-year period, children (aged 6 months to 18 years) (n = 2085) who presented with pharyngitis to the children's hospital emergency department and two outpatient offices were enrolled in a cross-sectional study to ascertain the role of large-colony-forming GCS and GGS in acute pharyngitis. Control patients (n = 194) were children who presented to the same locations during the same time period with non-respiratory tract symptoms or to the orthopaedic cast clinic. Throat cultures were obtained by a standard reference method, and swabs were plated on Strep-Selective Agar. Lancefield grouping and species identification was performed on all β-haemolytic isolates. In total, 65 (3%) large-colony-forming GCS and GGS strains were obtained from pharyngitis patients, and three (1.5%) were obtained from the control group (odds ratio 2.0; 95% confidence interval 0.6–6.1). The low isolation rate of large-colony-forming strains of GCS and GGS indicates that even if these organisms are associated with acute, sporadic pharyngitis in paediatric patients, they represent an unusual pathogen.