Antimicrobial susceptibility patterns, emm type distribution and genetic diversity of Streptococcus pyogenes recovered in Brazil

Streptococcus pyogenes is responsible for a variety of infectious diseases and immunological complications. In this study, 91 isolates of S. pyogenes recovered from oropharynx secretions were submitted to antimicrobial susceptibility testing, emm typing and pulsed-field gel electrophoresis (PFGE) analysis. All isolates were susceptible to ceftriaxone, levofloxacin, penicillin G and vancomycin. Resistance to erythromycin and clindamycin was 15.4%, which is higher than previous reports from this area, while 20.9% of the isolates were not susceptible to tetracycline. The macrolide resistance phenotypes were cMLSB (10) and iMLSB (4). The ermB gene was predominant, followed by the ermA gene. Thirty-two emm types and subtypes were found, but five (emm1, emm4, emm12, emm22, emm81) were detected in 48% of the isolates. Three new emm subtypes were identified (emm1.74, emm58.14, emm76.7). There was a strong association between emm type and PFGE clustering. A variety of PFGE profiles as well as emm types were found among tetracycline and erythromycin-resistant isolates, demonstrating that antimicrobial resistant strains do not result from the expansion of one or a few clones. This study provides epidemiological data that contribute to the development of suitable strategies for the prevention and treatment of such infections in a poorly studied area.

Genotyping of group A streptococcus by various molecular methods.

BACKGROUND & OBJECTIVE: Group A streptococcus (GAS) causes a wide variety of life threatening diseases in developing countries like India. Characterization of GAS is therefore necessary for prevention and control of the disease. Genotypic analysis of GAS is largely lacking from India, therefore an attempt was made to study the genotype distribution of north Indian GAS isolates. METHODS: Sixty clinical isolates of GAS, (52 collected from pharyngitis and 8 from RF/RHD patients) were genotyped by various molecular techniques like restriction enzyme analysis (REA), ribotyping, PCR-ribotyping and random amplification of polymorphic DNA (RAPD). A few isolates were also typed by emm gene sequencing for comparison. RESULTS: REA using Hind III digestion differentiated the isolates into six different patterns. The same isolates were grouped into three ribotypes when analyzed for PCR - ribotyping of 16S- 23S rRNA region. However, RAPD fingerprints generated higher level of discrimination by AP4 and AP5 primers showing 12 rapdemes, followed by AP3, AP2 and API producing 11, 9 and 6 rapdemes respectively. A total of 78 RAPD fragments or rapdemes were generated, of which 48 (62%) were shared and 30 (38%) were unique. These unique RAPD fragments could be used as a genetic marker for identification of GAS. Representative isolates that produced 12 different rapdemes by AP5, on further confirmation by emm typing showed 11 different emm types. INTERPRETATION & CONCLUSION: The finding of our study demonstrated the RAPD profiling to be the most discriminatory for genotyping of group A streptococcus isolates as well as comparable to the most commonly used sophisticated technique of emm typing.

Interpersonal relationships and group A streptococcus spread in a Mexican day-care center

OBJECTIVE: To study the effect of different degrees of centrality on the carrying of identical group A streptococcus (GAS) clones in the nasopharynx of children from a Mexican public day-care center. MATERIAL AND METHODS: Nasopharyngeal cultures were performed in children from rooms B (RB) (n = 35) and C (RC) (n = 37). The Restriction Fragment Length Polymorphism (RFLP) patterns were compared among GAS isolates. A social networks questionnaire was filled out for each child and 10 classmates. Structure coefficients were compared among children with and without GAS. RESULTS: Four GAS clones were identified; clone I in five children from RC; clone II in two from RC and one from RB; clone III in one from RB and one from RC; and clone IV in one from RC. Social network structure: Density of RB and RC = 0.40 (± 0.87) and 0.35 (± 0.80), respectively. In RB, the homophily pattern of interaction was different in carriers (0.00), non-carriers (0.47) and both (0.47) p = 0.35. In RC, the homophily pattern was also different in carriers (0.46), non-carriers (0.68) and mixed (0.19), p = .001. In 4/5 with clone I, the values of degree, closeness and betweenness were above the group mean. In 3/3 with clone II, the values of degree and betweenness were also above the mean. In contrast, in those with clone III and IV, the values of degree, closeness and betweenness were below the group mean. CONCLUSION: The spread of specific GAS clones was associated with groups of children having a high proportion of ties and a high centrality level. This is evidence that spread of GAS strains among children attending day-care centers is not random but dependent on the degree of communication and physical contact between pairs.

OBJETIVO: Evaluar el efecto de grados diferentes de centralidad con la presencia de clonas idénticas de estreptococo del grupo A (EGA) en la nasofaringe de niños de una guardería pública de México. MATERIAL Y MÉTODOS: Se realizaron cultivos nasofaríngeos en niños de los salones B (SB) (n = 35) y C (SC) (n = 37). El patrón de polimorfismos de longitud de fragmento por restricción (Restriction Fragment Length Polymorphism, RFLP) fue comparado entre aislamientos de EGA. Un cuestionario de redes sociales fue llenado para cada niño y 10 compañeros. Los coeficientes de estructura fueron comparados entre niños con y sin EGA. RESULTADOS: Se identificaron cuatro clonas de EGA. Clona I en cinco niños del SC; clona II en dos del SC y en uno del SB; clona III en uno del SB y uno del SC; y clona IV en uno del SC. Estructura de redes sociales: Densidad SB y SC = 0.40 (± 0.87) y 0.35 (± 0.80), respectivamente. En SB, el patrón de homofilia de la interacción fue distinto en portadores (0.00), no portadores (0.47) y ambos (0.47) p = 0.35. En SC, el patrón de homofilia fue distinto en portadores (0.46), no portadores (0.68) y mixto (0.19), p = .001. En 4/5 con la clona I, los valores de grado, cercanía e intermediación estuvieron por arriba de la media grupal. En 3/3 con la clona II, los valores de grado e intermediación estuvieron por arriba de la media grupal. En contraste, en los niños con clonas III y IV, los valores de grado, cercanía e intermediación estuvieron por debajo de la media grupal. CONCLUSIONES: La diseminación de clonas específicas de EGA se asoció a grupos de niños con gran proporción de lazos entre ellos y un alto nivel de centralidad. Esto evidencia que la transmisión de EGA entre niños de guardería no ocurre al azar sino que depende del grado de comunicación y contacto físico entre éstos.

Coréia de Syndenham: uma dança entre o Streptococcus, o sistema imune e os núcleos da base / Syndenham's chorea: a dance involving the Streptococcus the immune system and the basal ganglia

A coréia de Syndenham (CS) é a manifestação da febre reumática e consiste em movimentos involuntários anormais que se assemelham a uma "dança". Em sua etiopatogênese, várias evidências apontam para mecanismos auto-imunes desencadeados por uma infecção na orofaringe pelo Streptococcus ß-hemolítico do grupo A. Esses processos imunes interferem no funcionamento dos núcleos da base, gerando desde o quadro motor de coréia até os distúrbios psiquiátricos associados à CS.

Microbiological diagnosis of streptococcal pharyngitis: lacunae and their implications.

Post-streptococcal sequelae, especially acute rheumatic fever/rheumatic heart disease continue to occur in significant proportions in many parts of the world. Despite several attempts with various intervention strategies, little success has been achieved in the control of acute rheumatic fever/rheumatic heart disease in India. The success of the control programmes depends upon timely primary prophylaxis with benzathine penicillin for which a microbiological confirmation of group A streptococcal pharyngitis is essential. Isolation of beta hemolytic streptococci from throat cultures and their identification as GAS in the laboratory, clinches the microbiological diagnosis while demonstration of a 'significant rise' in antibody titers such as Anti-streptolysin O and Anti-deoxyribonuclease B differentiates it from a group A streptococcal carrier state or pharyngitis of a viral etiology. Despite the easiness with which these can be achieved, many laboratories in India are not equipped to do so. Enhancing bacteriological and serological facilities in laboratories across the country will drastically improve the clinician's ability to diagnose bona fide GAS pharyngitis and help to institute penicillin prophylaxis at the appropriate time. This will go a long way in enhancing the compliance to penicillin prophylaxis which is the cornerstone of any RF/RHD control program.

Evaluation of simplified DNA extraction methods for emm typing of group A streptococci.

Simplified methods of DNA extraction for amplification and sequencing for emm typing of group A streptococci (GAS) can save valuable time and cost in resource crunch situations. To evaluate this, we compared two methods of DNA extraction directly from colonies with the standard CDC cell lysate method for emm typing of 50 GAS strains isolated from children with pharyngitis and impetigo. For this, GAS colonies were transferred into two sets of PCR tubes. One set was preheated at 94 degrees C for two minutes in the thermal cycler and cooled while the other set was frozen overnight at -20 degrees C and then thawed before adding the PCR mix. For the cell lysate method, cells were treated with mutanolysin and hyaluronidase before heating at 100 degrees C for 10 minutes and cooling immediately as recommended in the CDC method. All 50 strains could be typed by sequencing the hyper variable region of the emm gene after amplification. The quality of sequences and the emm types identified were also identical. Our study shows that the two simplified DNA extraction methods directly from colonies can conveniently be used for typing a large number of GAS strains easily in relatively short time.

Characterisation of group A streptococcal (GAS) isolates from children with tic disorders.

BACKGROUND & OBJECTIVES: An association between the onset or recrudescence of some neuropsychiatric disorders in children such as tic disorders and group A streptococcal (GAS) infections has been suggested. No information is available on the characterization of GAS strains associated with such disorders. The present study was undertaken to characterize the GAS strains isolated from children with tic disorders and to determine and correlate the antistreptolysin O (ASO) titre with the presence of GAS. METHODS: During 1996-2001, 368 children with tic disorders were investigated for possible exposition to streptococcal antigens. All children, at the time of the first visit and during the follow up visits were apparently healthy and showed no clinical evidence of streptococcal infections or post streptococcal sequelae. Blood and throat swab samples were collected and serological and bacteriological tests done. The isolates obtained were investigated for T pattern, M protein and emm type, as well as for the production of protease. RESULTS: Of the 800 throat swabs studied 100, corresponding to 67 patients, were positive for GAS; 49 children were found positive for GAS only once during the study, 18 had more than one sample positive for different serotypes, 8 were positive twice or more for the same type. ASO titres of these children were, in general, elevated. Five types, namely type M12, 3, 13, 11, 1, accounted for 39 per cent of the isolates, M12 being the most common, but a large number of different types were also found. A large number of isolates (62%) showed an elevated prodution of protease in the casein plate assay. INTERPRETATION & CONCLUSION: Despite the high level of ASO titres found, the results were not in favour of a particular virulence or invasivity of the isolates. Only a few colonies per sample were found indicating that factors different from the microbial virulence play a role in this type of disease.

Group A streptococci in children with acute pharyngitis in Sousse, Tunisia

A 1-year prospective study in 2 paediatric outpatient clinics in Sousse, Tunisia, aimed to determine the presence of group A streptococci in acute pharyngitis cases and carriers, and the distribution of the serotypes and biotypes. Group A streptococci were found in 9.0% of throat swabs from 155 controls and 17.7% from 474 patients [P < 0.05]. Of 43 strains isolated from patients and submitted for typing, 15 different types were identified, the most common being M75 [14 strains; 32.5%], M9 [6 strains; 14.0%], M76 [5 strains; 11.6%] and M12 [4 strains; 9.3%]. Three strains were non-typeable [7.0%]. Biotyping of the strains showed 3 predominant biotypes: biotype 3 [n = 14], biotype 2 [n = 11], and biotype 1 [n = 7]

Resistance pattern of bacteria isolated from acute respiratory tract infection (ARI) cases.

Out of 350 acute respiratory tract infection (ARI) patients 110 (31.4%) were positive on culture. Among then (35.5%) yielded from upper respiratory tract infection (URI) and 64.5% yielded from lower respiratory tract infection (LRI). Predominant bacterial isolates from URI were Staph aureus (12.4%) and Strepto. pyogen (9.8%) whereas predominant agent from LRI were Strepto. pneumoniae (14.7%) and Haemophilus influenzae (8.6%). Capsular typing by polymerase chain reaction (PCR) and type specific antisera revealed that 64.7% of the isolates were type-b and rest were non-b. The most frequent resistance pattern of H. influenzae was found resistant to penicillin-ampicillin (64.7%) followed by SMX-TMP (14.7%) and tetracycline (5.9%). Among penicillin-ampicillin resistant strains, 81.8% were beta lectamase positive and 18.2% were beta lectamase negative. Among beta lectamase positive strains 66.7% were capsular type-b and 33.3% were non-b, had MICS < or = 8 microgram/ml. and < or = 4 microgram/ml. respectively. 5.9% strains of Strepto. pneumoniae was found resistant to SMX-TMP, 5.9% to penicillin-ampicillin and 2.9% to cephalexin. Common resistance pattern of Staph aureus was penicillin-ampicillin (60%), SMX-TMP (37.2%) and tetracycline-erythromycine-cephalexin (11.4%). Strepto. pyogen was found resistant to tetracycline in 12.2% cases and to SMX-TMP in 8.3% cases.

Bacteriologic characteristics and serotypings of Streptococcus pyogenes isolated from throats of school children

To determine the carrier rate of beta-hemolytic streptococci (BHS), throat cultures were taken from healthy elementary school children in four separate areas of Korea from 1992 to 1995, including Inje, Nonsan, Seoul and Chinju. The strains of Streptococcus pyogenes had been serotyped with anti-T, -OF and -M sera. The isolation rates of BHS and S. pyogenes ranged from 14.1-32.4% and 10.9-18.5% respectively. More than half of the carriers showed heavy growth of BHS. M78 (48.6%) and M28 (22.2%) were most common in Inje, M12 (23.6%) and M5 (20.3%) in Nonsan, M12 (48.8%) and M5 (14.6%) in Seoul, and M12 (26.3%) and M22 (14.5%) in Chinju, respectively. About 15% of school children were positive for S. pyogenes in throat cultures, and the distribution of serotypes varied according to geographical regions.

Effects of intranasal challenge with group A beta haemolytic streptococcus M type 49 in Swiss albino mice.

Mice are susceptible to natural infections with streptococci and therefore can serve as suitable animal models to study experimental streptococcal infections. In an earlier study, we had shown the development of pharyngeal colonization, antibody response and histopathological changes in the heart following intranasal (IN) challenge with a rheumatogenic serotype of group A beta haemolytic streptococcus, the M type 18. To determine if nonpharyngitis associated serotypes can also elicit similar responses, 30 Swiss albino mice were challenged intranasally with 2 x 10(7) colony forming units of a skin associated serotype of group A beta haemolytic streptococcus, the M type 49. Pharyngeal colonization varied from 64% (n = 30) in the first week to 69% (n = 16) during the fourth week after IN challenge. Eleven (36.7%) of the 30 animals studied showed antibody response to DNase B (ADNB) with peak titers varying from 150 to 1200 units. Wide variations were seen in ADNB titers in individual mice. Histopathological evidence for cardiac lesions were seen in three animals. The changes were mild and varied from mild to chronic endocardial inflammation to calcification. The study shows that Swiss albino mice are also susceptible to IN challenge with skin associated strains of GABHS and therefore can serve as useful models to study the effects of experimental infection with diverse serotypes of GABHS.

Bacteremia due to beta haemolytic streptococci.

The Beta haemloytic streptococci (BHS) are well recognised human pathogens causing a variety of infections, including septicemia. It is important to ensure their isolation from clinical specimens by using optimum media. Moreover, since the different groups have different pathogenic potential, it is equally important to routinely serogroup them; this is emphasized here. Since, BHS are uniformly will greatly decrease morbidity and mortality due to BHS infection.

Comparison of M-serotypes of Streptococcus pyogenes isolated from healthy elementary school children in two rural areas

Serotypings have been used as markers for epidemiological surveys of Streptococcus pyogenes infections. Seventy-seven strains of S. pyogenes isolated from the throats of elementary school children in Kangwon Province in Korea in March and April 1992 were serotyped with M and/or opacity factor (OF) antisera. Sixty-eight strains of S. pyogenes from healthy school children in Chungnam Province in March 1993 were also serotyped and the distribution of serotype was compared with the isolates from those living in Kangwon Province. The distributions of M types were quite different between the two areas. M-78 (46.8%) and M-28 (22.1%) were most frequently encountered in Kangwon Province, while M-5 (20.6%), M-12 (16.2%), M-3 (13.2%), M-1 (11.8%) and M-62 (11.8%) were frequently isolated in Chungnam Province. Eighty-seven percent of strains in Kangwon produced OF while 33.2% of those in Chungnam produced OF (p< 0.0001). The difference in the distribution of serotypes and of OF production in the isolates from the children in the two provinces may be responsible for differences in the epidemiology of group A streptococcal infections and their sequelae.

Síndrome shock tóxico semejante: reporte de un caso / Syndrome toxic shock like: report of case

Nosotros describimos un paciente con lesiones espontáneas ulcerosas, en sacabocado, localizadas en la región escapular derecha, septicemia e infección por Strepcoco Pyogens. El paciente presentó los signos y síntomas siguientes: fiebre, vómito, mialgias, desorientación, complicado con derrame pericárdico purulento, derrame pleural, meningitis, endoftalmitis ojo derecho. Recuperándose después de la terapia antimicrobiana empleada inicialmente; Vancomicina-Tobramicina, vía endovenosa, posteriormente cambiada a Penicilina Cristalina al obtener los resultados de hemocultivo

Faringitis estreptocócicas en pediatría: frecuencia de los distintos estreptococos ß-hemolíticos / Streptococcal pharyngitis: different ß-hemolitic streptococci frecuency

El objetivo de este trabajo fue determinar la frecuencia de los estreptococos ß-hemolíticos aislados de exudados de fauces en niños de 0 a 16 años que concurrieron al hospital entre el 1-10-91 y el 30-9-92. De 5.700 muestras procesadas, 17,1 por ciento desarrollaron estreptococos ß-hemolíticos en agar sangre de carnero, incubadas a 37§C durante 24 y 48 horas en atmósfera enriquecida en CO2. Para su identificación se utilizaron las siguientes pruebas: sensibilidad a la bacitracina (Bac), hidrólisis del ácido L - pirrolidonil ß- naftilamida (PYR), clasificación de Lancefield y test de Voges - Proskauer modificado. La identificación de especies del grupo C colonia grande se realizó en base a la fermentación de trealosa y sorbitol. El estreptococo ß-hemolítico grupo A (EBHGA) representó el mayor número de aislamientos (84,2 por ciento), habiendo sido posible identificar como S. pyogenes el 57 por ciento del total y estreptococos presumiblemente del grupo A al 27,2 por ciento. Se documentó un 6,5 por ciento de S. equisimilis, 4,4 por ciento de estreptococos grupo G colonia grande y 1,1 por ciento de S. anginosus. Al 3,8 por ciento de las cepas sin halo de bacitracina no se les pudo realizar serología. El grupo etáreo más afectado correspondió a niños entre 4 y 6 años. En los menores de 2 años se aisló el 3,5 por ciento de todos los estreptococos ß-hemolíticos. Se encontró relación estacional en los EBHGA, no así en los no grupo A. La correcta identificación de los diferentes estreptococos ß-hemolíticos requiere una combinación precisa de pruebas bioquímicas y serológicas, las cuales están al alcance de un laboratorio de microbiología clínica. El resultado oportuno puede tener implicancia terapéutica y epidemiológica frente al paciente y su entorno