Epidemiología de la faringitis estreptocócica. Período enero de 2018 - diciembre de 2021 / Epidemiology of streptococcal pharyngitis. January 2018 - December 21

La faringoamigdalitis es uno de los motivos más frecuentes de consulta en pediatría. Aproximadamente un 70-80% de las faringoamigdalitis son de etiología viral. El 20-30% restante son de origen bacteriano. El agente causal más frecuente es Streptococcus pyogenes (estreptococo ß-hemolítico del grupo A). El rol de Streptococcus dysgalactiae subsp. equisimilis, (estreptococos ß-hemolíticos grupos C y G) fue claramente establecido como agente etiológico en la faringitis bacteriana, tanto en niños como en adultos. Se realizó un análisis descriptivo y retrospectivo entre enero 2018 y diciembre de 2021. Se evaluó la prevalencia de faringitis estreptocócica, la edad, el período estacional, los agentes etiológicos y la resistencia a macrólidos durante los períodos pre-COVID-19 (2018-2019) y COVID-19 (2020-2021). Se analizaron 11 396 muestras de exudados de fauces de pacientes con sospecha de faringitis bacteriana; las mismas se procesaron mediante el uso de técnicas microbiológicas convencionales. En el período estudiado el porcentaje de positividad de los cultivos de exudados de fauces se mantuvo constante. Al comparar los períodos pre-COVID-19 (2018-2019) y COVID-19 (2020-2021) se observó una disminución en el número de aislados de S. pyogenes con un aumento de S. dysgalactiae subsp. equisimilis, mientras que la resistencia a macrólidos encontrada fue superior en S. pyogenes y para S. dysgalactiae subsp. equisimilis se mantuvo constante. Es importante realizar el cultivo para la identificación del agente etiológico y determinar la sensibilidad antibióticapara continuar con la vigilancia epidemiológica de la resistencia a los macrólidos, porque representan una opción en pacientes alérgicos a ß-lactámicos (AU)

Pharyngotonsillitis is one of the most frequent reasons for consultation in children. Approximately 70-80% of pharyngotonsillitis are of viral etiology. The remaining 20-30% are bacterial in origin. The most frequent causative agent is Streptococcus pyogenes (group A ß-hemolytic streptococcus). Streptococcus dysgalactiae subsp. equisimilis (ß-hemolytic streptococcus groups C and G) was clearly established as an etiologic agent in bacterial pharyngitis in both children and adults. A descriptive and retrospective analysis was conducted between January 2018 and December 2021. The prevalence of streptococcal pharyngitis, age, seasonal period, etiologic agents, and macrolide resistance during the pre-COVID-19 (2018-2019) and COVID-19 (2020-2021) periods were evaluated. We analyzed 11 396 specimens of swabs from patients with suspected bacterial pharyngitis. Conventional microbiological techniques were used. In the study period, the percentage of positivity of swab cultures remained constant. When comparing the preCOVID-19 (2018-2019) and COVID-19 (2020-2021) periods, a decrease in the number of S. pyogenes isolates was observed with an increase in S. dysgalactiae subsp. equisimilis, while the resistance to macrolides found was higher for S. pyogenes and remained constant for S. dysgalactiae subsp. equisimilis. The identification of the etiologic agent and determination of antibiotic sensitivity are important for epidemiological surveillance of macrolide resistance, as they are a treatment option in patients who are allergic to ß-lactams (AU)

Sensibilidad disminuida a los antibóticos Beta-Lactamicos en estreptococos Beta-Hemolíticos / Decreased sensitivity to beta-lactam antibiotics in beta-hemolytic streptococci

Últimamente, se están detectando mutaciones en las proteínas ligadoras de penicilina (PBP) de los estreptococos beta-hemolíticos que corresponden a sitios que en Streptococcus pneumoniae han determinado sensibilidad disminuida a los antibióticos beta-lactámicos. Primero, se describieron cepas con sensibilidad intermedia a penicilina en Streptococcus agalactiae (estreptococos del grupo B), luego en Streptococcus dysgalactiae subsp. equisimilis (mayormente grupos C y G) y, más recientemente, cepas con sensibilidad disminuida a aminopenicilinas y cefalosporinas de tercera generación en Streptococcus pyogenes (grupo A). El costo biológico de estas modificaciones nos permite pensar que los niveles de resistencia no han de ser tan elevados como para comprometer por ahora la efectividad clínica de los beta-lactámicos (AU)

Recently, mutations in penicillin-binding proteins (PBPs) of beta-hemolytic streptococci have been detected corresponding to sites that in Streptococcus pneumoniae have been determined to have decreased sensitivity to beta-lactam antibiotics. First, strains with intermediate sensitivity to penicillin were described in Streptococcus agalactiae (group B streptococci), subsequently in Streptococcus dysgalactiae subsp. equisimilis (mainly groups C and G) and, more recently, strains with decreased sensitivity to third-generation aminopenicillins and cephalosporins were found in Streptococcus pyogenes (group A). The biological cost of these modifications suggests that, for now, resistance levels are not high enough to compromise the clinical effectiveness of beta-lactams (AU)

Comparison of Characteristics of Streptococcus dysgalactiae subsp. equisimilis Isolates Causing Repetitive vs Single Infections

No study has described Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates that cause repetitive infections (recurrence and reinfection). We compared the microbiological characteristics of SDSE causing repetitive infections with those causing single infections. Three patients with invasive infections were identified based on their medical records, and multiple SDSE isolates were collected at intervals over three weeks, using a laboratory repository. Isolates from 12 patients with single-episode infections served as controls. Six isolates were collected from three patients with first and second episodes of infection. All isolates causing either repetitive or single-episode infection were subjected to emm typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and random amplified polymorphic DNA (RAPD) analyses. Amplification of five virulence genes (sicG, prtF1, prtF2, lmb, and cbp), biofilm formation (BF), and cell invasion abilities (CIAs) were measured as virulent phenotypes. We observed close genetic similarities in the data obtained by emm typing, MLST, PFGE, and RAPD in four isolates from two patients, suggesting recurrence, whereas two isolates from one patient indicated genetic differences in these data, suggesting re-infection. The presence of the five virulence genes and the BF and CIA measurements appeared not to contribute to repetitive infections, compared with isolates causing single-episode infection. In conclusion, clinicians encountering patients with repetitive infections should be aware of both possibilities: recurrence with closely related strains and reinfection with different strains.

Susceptibility to β-lactams in β-hemolytic streptococci / Sensibilidad a los β-lactámicos en estreptococos β-hemolíticos

Group A (GAS), B (GBS), c (GCS) and G (GGS) β-hemolytic streptococci are important human pathogens. They cause infections of different severity and frequency. Nowadays, after 70 years of use, penicillin is still universally active against GAS, GCS and GGS. However, therapeutic failures have been recorded in 2-28% of pharyngitis cases (median: 12%) attributable to different causes. By contrast, some GBS with reduced susceptibility to penicillin have been described, especially in Japan. In this group of bacteria, it is important to highlight that confirmation by reference methods is mandatory when decreased susceptibility to penicillin is suspected as well as checked for the detection of the mechanisms involved.

Los estreptococos β-hemolíticos de los grupos A (GAS), B (GBS), C (GCS) y G (GGS) son importantes patógenos humanos. Ellos producen infecciones de diversa gravedad y frecuencia. Aún después de más de 70 años de uso, la penicilina sigue siendo activa in vitro frente al 100% de los GAS, GCS y GGS. No obstante se han producido fallas terapéuticas entre el 2-28% de los casos de faringitis (media: 12%), atribuibles a diversas causas. En cambio se han descrito aislados de GBS con sensibilidad reducida a la penicilina, especialmente en Japón. Es importante que toda sospecha de sensibilidad disminuida a la penicilina en este grupo de bacterias sea confirmada por los métodos de referencia y comprobada mediante la detección de los mecanismos involucrados.

Epidemiología de la faringitis aguda bacteriana en un hospital general de agudos / Epidemiology of acute bacterial pharyngitis in a general acute care hospital / Epidemiologia da faringite bacteriana aguda em um hospital geral de cuidados agudos

La faringitis aguda bacteriana (FAB) representa entre un 20 a 30% de las faringitis. El principal agente causal es Streptococcus pyogenes. Se revisó retrospectivamente la información microbiológica disponible entre 2010 y 2016, para analizar la incidencia de la FAB, sus agentes causales, la incidencia de casos según el período estacional y rango etario. Se determinó el porcentaje de resistencia (R) de S. pyogenes a eritromicina y el fenotipo predominante. Se diagnosticó FAB en 21,5% de 3.246 cultivos, donde 89% fueron causados por S. pyogenes. El 35,3% de las FAB se presentó en niños de 7 a 10 años, seguido por el grupo de mayores de 15 años (31,3%). Se evidenció un aumento de faringitis por Streptococcus dysgalactiae subsp. equisimilis en 2011 y 2014; 56,2% de los casos se diagnosticaron en mayores de 15 años. Hubo 3 casos de FAB por Arcanobacterium haemolyticum. El 36,1% de las faringitis se presentaron en primavera, con un aumento significativo durante las correspondientes a 2010 y 2016. La R global a eritromicina en S. pyogenes fue del 16,6% con predominio del fenotipo M. El valor de R encontrado fue superior al ser comparado con otras estadísticas similares, lo que demostró la importancia de monitorear este dato, dado que es el antibiótico alternativo en pacientes alérgicos a penicilina.

Acute bacterial pharyngitis (ABP) accounts for 20 to 30% of acute pharyngitis. The most common bacterial agent is Streptococcus pyogenes. A retrospective, record-based study was carried out based on the microbiological records from 2010 to 2016, analyzing ABP's incidence, its causal agents and its incidence according to the season and age range. Erythromycin resistance and the main resistance phenotype were determined in S. pyogenes. Acute bacterial pharyngitis was diagnosed in 21.5% out of 3.246 cultures, 89% were due to S. pyogenes, 36.3% of patients were children between 7 to 10 years old and 31.3% were older than 15 years of age. There was a significant increase in pharyngitis due to Streptococcus dysgalactiae subsp. equisimilis since 2010 (p<0.05), 52.5% were detected in patients older than 15 years of age. There were only three cases of ABP produced by Arcanobacterium haemolyticum. A total of 36.1% of pharyngitis occurred during spring, with a significant increase during 2010 and 2016 springs. Global erythromycin resistance in S. pyogenes was 16.6% with predominance of the M phenotype. This resistance rate is higher than that described in other similar series, demonstrating the importance of continuously monitoring of macrolide R in S. pyogenes, since they are the antibiotics of choice to treat pharyngitis in patients allergic to penicillin.

A faringite bacteriana aguda (FAB) representa entre 20 e 30% das faringites. O principal agente causador é Streptococcus pyogenes. Foi revista retrospectivamente a informação microbiológica disponível entre 2010 e 2016, para analisar a incidência da FAB, seus agentes causadores, a incidência de casos de acordo com o período sazonal e a faixa etária. A percentagem de resistência (R) de S. pyogenes à eritromicina e ao fenótipo predominante foram determinadas. Foi diagnosticado FAB em 21,5% de 3,246 culturas, 89% das quais foram causadas por S. pyogenes. 35,3% das FAB se apresentou em crianças de 7 a 10 anos, seguidas pelo grupo de mais de 15 anos (31,3%). Houve aumento de faringite por Streptococcus dysgalactiae subsp. equisimilis em 2011 e 2014; 56,2% dos casos foram diagnosticados em jovens de mais de 15 anos. Houve 3 casos de FAB por Arcanobacterium haemolyticum. 36,1% das faringites ocorreu na primavera, com um aumento significativo em 2010 e 2016. A R global a eritromicina em S. pyogenes foi de 16,6% com prevalência do fenótipo M. O valor de R encontrado foi superior em comparação com outras estatísticas semelhantes, demonstrando a importância de monitorar esse dado, pois é o antibiótico alternativo em pacientes alérgicos à penicilina.

Molecular Epidemiological Features and Antibiotic Susceptibility Patterns of Streptococcus dysgalactiae subsp. equisimilis Isolates from Korea and Japan

BACKGROUND: The molecular characterization of Streptococcus dysgalactiae subsp. equisimilis (SDSE) has not yet been performed in Korea. This study aimed to find the differences or similarities in the clinical features, molecular epidemiological findings, and antimicrobial resistance patterns of SDSE from two countries (Korea and Japan). METHODS: SDSE isolates were collected from Korea (N=69) from 2012–2016 and Japan (N=71) from 2014–2016. Clinical characteristics, emm genotypes, and sequence types (STs) were compared. Microdilution tests were performed using different antimicrobials, and their resistance determinants were screened. RESULTS: Median ages were 69 years in Korea and 76 years in Japan. The most common underlying diseases were diabetes and malignancy. Blood-derived isolates comprised 36.2% and 50.7% of Korean and Japanese isolates, respectively; mortality was not different between the two groups (5.8% vs 9.9%, P=0.53). Among Korean isolates with 20 different combined ST-emm types, ST127-stG245 (N=16), ST128-stG485 (N=10), and ST138-stG652 (N=8) were prevalent. Among Japanese isolates with 29 different combined types, ST17-stG6792 (N=11), ST29-stG485 (N=7), and ST205-stG6792 (N=6) were prevalent. Resistance rates to erythromycin, clindamycin, and minocycline were 34.8%, 17.4%, and 30.4% in Korea and 28.2%, 14.1%, and 21.4% in Japan, respectively. CONCLUSIONS: SDSE infections commonly occurred in elderly persons with underlying diseases. There was a significant difference in the distribution of ST-emm types between the two countries. Antimicrobial resistance rates were comparable with different frequencies of resistance determinants in each country.

Prevalence of Complement-Mediated Cell Lysis-like Gene (sicG) in Streptococcus dysgalactiae subsp. equisimilis Isolates From Japan (2014–2016)

BACKGROUND: Streptococcus dysgalactiae subsp. equisimilis (SDSE; a β-hemolytic streptococcus of human or animal origin) infections are emerging worldwide. We evaluated the clonal distribution of complement-mediated cell lysis-like gene (sicG) among SDSE isolates from three central prefectures of Japan. METHODS: Group G/C β-hemolytic streptococci were collected from three institutions from April 2014 to March 2016. Fifty-five strains (52 from humans and three from animals) were identified as SDSE on the basis of 16S rRNA sequencing data.; they were obtained from 25 sterile (blood, joint fluid, and cerebrospinal fluid) and 30 non-sterile (skin-, respiratory tract-, and genitourinary tract-origin) samples. emm genotyping, multilocus sequence typing, sicG amplification/sequencing, and random amplified polymorphic DNA (RAPD) analysis of sicG-positive strains were performed. RESULTS: sicG was detected in 30.9% of the isolates (16 human and one canine) and the genes from the 16 human samples (blood, 10; open pus, 3; sputum, 2; throat swab, 1) and one canine sample (open pus) showed the same sequence pattern. All sicG-harboring isolates belonged to clonal complex (CC) 17, and the most prevalent emm type was stG6792 (82.4%). There was a significant association between sicG presence and the development of skin/soft tissue infections. CC17 isolates with sicG could be divided into three subtypes by RAPD analysis. CONCLUSIONS: CC17 SDSE harboring sicG might have spread into three closely-related prefectures in central Japan during 2014–2016. Clonal analysis of isolates from other areas might be needed to monitor potentially virulent strains in humans and animals.

Caracterización molecular de cepas invasivas de Streptococcus dysgalactiae subsp. equisimilis: estudio multicéntrico Argentina 2011-2012 / Molecular characterization of invasive Streptococcus dysgalactiae subsp. equisimilis. Multicenter study: Argentina 2011-2012

Streptococcus dysgalactiae subsp. equisimilis (SDSE) has virulence factors similar to those of Streptococcus pyogenes. Therefore, it causes pharyngitis and severe infections indistinguishable from those caused by the classic pathogen. The objectives of this study were: to know the prevalence of SDSE invasive infections in Argentina, to study the genetic diversity, to determine the presence of virulence genes, to study antibiotic susceptibility and to detect antibiotic resistance genes. Conventional methods of identification were used. Antibiotic susceptibility was determined by the disk diffusion and the agar dilution methods and the E-test. Twenty eight centers from 16 Argentinean cities participated in the study. Twenty three isolates (16 group G and 7 group C) were obtained between July 1 2011 and June 30 2012. Two adult patients died (8.7%). Most of the isolates were recovered from blood (60.9%). All isolates carried speJ and ssa genes. stG62647, stG653 and stG840 were the most frequent emm types. Nineteen different PFGE patterns were detected. All isolates were susceptible to penicillin and levofloxacin, 6 (26.1%) showed resistance or reduced susceptibility to erythromycin --#91;1 mef(A), 3 erm(TR), 1 mef(A) + erm(TR) and 1 erm(TR) + erm(B)--#93; and 7 (30.4%) were resistant or exhibited reduced susceptibility to tetracycline --#91;2 tet(M), 5 tet(M) + tet(O)--#93;. The prevalence in Argentina was of at least 23 invasive infections by SDSE. A wide genetic diversity was observed. All isolates carried speJ and ssa genes. Similarly to other studies, macrolide resistance (26.1%) was mainly associated to the MLS B phenotype.

Streptococcus dysgalactiae subsp. equisimilis (SDSE) posee factores de virulencia similares a Streptococcus pyogenes y, en consecuencia, produce faringitis e infecciones graves indistinguibles de las generadas por este patógeno clásico. Los objetivos del estudio fueron conocer la prevalencia de SDSE en infecciones invasivas en Argentina, estudiar su diversidad genética, determinar la presencia de genes de virulencia, ensayar su sensibilidad a los antibióticos y conocer los genes de resistencia. Se emplearon métodos convencionales de identificación. La sensibilidad se determinó por difusión, Etest y dilución en agar. Participaron 28 centros de 16 ciudades argentinas. Se obtuvieron 23 aislamientos (16 del grupo G y 7 del grupo C) desde el 1-7-2011 hasta el 30-6-2012. Se registraron 2 muertes en adultos (8,7%). La mayoría de los aislamientos fueron obtenidos de sangre (60,9%). Todos eran portadores de los genes speJ y ssa. Los genotipos más frecuentes fueron stG62647, stG653 y stG840. Se detectaron 19 pulsotipos distintos. Todos los aislamientos fueron sensibles a penicilina y levofloxacina, 6 (26,1%) presentaron resistencia o sensibilidad disminuida a eritromicina (1 mef--#91;A--#93;, 3 erm--#91;TR--#93;, 1 mef--#91;A--#93; + erm--#91;TR--#93; y 1 erm--#91;TR--#93; + erm--#91;B--#93;) y 7 (30,4%) fueron resistentes o tuvieron sensibilidad disminuida a tetraciclina (2 tet--#91;M--#93;, 5 tet--#91;M--#93; + tet--#91;O--#93;). La prevalencia anual en la Argentina fue de al menos 23 infecciones invasivas por SDSE y se observó una amplia diversidad genética. Todos los aislamientos presentaron los genes ssa y speJ. Como en otros estudios, la resistencia a macrólidos (26,1%) estuvo asociada, principalmente, al fenotipo MLS B.

Endocarditis infecciosa por Streptococcus dysgalactiae subsp equisimilis / Infective endocarditis by Streptococcus dysgalactiae subsp equisimilis

La infección por Streptococcus dysgalactiae subsp equisimilis es causa frecuente de faringitis, artritis e infecciones de piel y tejidos blandos; excepcionalmente se ha descrito como causa de endocarditis infecciosa. Se presenta el caso de un paciente masculino de 42 años quien ingresa al Hospital Vargas de Caracas con fiebre, astenia, dolor en hombro derecho con limitación funcional y dolor en hipocondrio derecho; a las 48 horas se evidencia soplo mesosistólico en foco mitral, hemorragias en astillas y lesiones de Janeway, por lo que se plantea Endocarditis Infecciosa, y se inicia tratamiento con Vancomicina + Gentamicina. Los hemocultivos muestran crecimiento de Streptococcus equisimilis en ambos frascos; el ecocardiograma transtorácico evidencia una vegetación en valva posterior de válvula mitral. Luego de 48 horas de inicio de tratamiento remite la fiebre. El ecocardiograma control a los 14 días mostró la desaparición de la vegetación en la válvula mitral. El paciente recibió tratamiento por 6 semanas

Streptococcus dysgalactiae subsp equisimilis is frequent in patients with pharyngitis, arthritis and skin infections; it rarely causes infective endocarditis. We describe a 42 year-old male patient complaining of fever, malaise, right shoulder pain and right upper quadrant pain who was admitted to the Hospital Vargas, Caracas, Venezuela. After 48 hours his physical examination revealed mesosystolic murmur at the apex, splinter hemorrhages and Janeway lesions, suggestive of Infective Endocarditis Blood cultures identified Streptococcus equisimilis; transthoracic echocardiogram revealed a vegetation over the posterior leaflet of mitral valve; the patient was treated with Vancomycin + Gentamycin. After 48 hours of treatment the fever subsided. A transthoracic echocardiogram after 14 days showed no vegetations. The patient was treated during 6 weeks