Beneath the surface: a case report on nonencapsulated Streptococcus pneumoniae-associated invasive disease in an immunocompromised patient.

Background: Streptococcus pneumoniae, a prominent human pathogen linked to various systemic diseases, includes non-typeable pneumococci marked by the absence of a detectable capsule. However, the majority of invasive infections are attributed to encapsulated strains. This case report details the first documented instance of invasive disease caused by non-typeable S. pneumoniae in Argentina since 2017. Case Presentation: A 19-year-old woman presented with haemorrhagic injuries attributed to chronic oral mucosa irritation. Subsequent hospitalization revealed bone marrow aplasia, leading to antibiotic, antifungal, antiviral, and immunosuppressive treatments, culminating in her discharge. Two weeks later, she was readmitted with sepsis related to a respiratory focus, exhibiting a negative COVID-PCR test. After ten days, ICU admission revealed additional infections: positive COVID-PCR test, fungal sinusitis, and S. pneumoniae bacteremia. Targeted treatments led to improvement, and the patient was subsequently discharged. S pneumoniae characterization: Verification of the capsule's absence utilized traditional methods such as the Quellung reaction, transmission electron microscopy, molecular assays, and Whole Genome Sequencing (WGS). The isolate, identified as ST18335, displayed genetic features and antibiotic resistance patterns, concordant between WGS and the agar dilution method. It demonstrated non-susceptibility to penicillin and cefotaxime, based on meningitis breakpoints, as well as meropenem and cotrimoxazole. Conclusion: This case underscores the clinical significance of non-typeable S. pneumoniae, emphasizing the necessity for a comprehensive approach to identification and characterization. The findings contribute to ongoing discussions regarding the challenges posed by non-typeable strains in vaccine development, understanding clinical impacts, and addressing antibiotic resistance. As the pneumococcal epidemiological landscape evolves, this case serves as a valuable addition to the evolving knowledge surrounding non-typeable S. pneumoniae, highlighting the continued need for surveillance and research in infectious diseases.

Exploring Streptococcus pneumoniae capsular typing through MALDI-TOF mass spectrometry and machine-learning algorithms in Argentina: Identifying prevalent NON PCV13 serotypes alongside PCV13 serotypes.

Introduction: Laboratory surveillance of Streptococcus pneumoniae serotypes plays a crucial role in effectively implementing vaccines to prevent invasive pneumococcal diseases. The conventional method of serotyping, known as the Quellung reaction, is both time-consuming and expensive. However, the emergence of MALDI-TOF MS technology has revolutionized microbiology laboratories by enabling rapid and cost-effective serotyping based on protein profiles. Objectives: In this study, we aimed to investigate the viability of utilizing MALDI-TOF MS technology as an adjunctive and screening method for capsular typing of Streptococcus pneumoniae. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates. Methods: Firstly, we established a comprehensive spectral database comprising isolates of serotypes present in the PCV13 vaccine, along with the top 10 most prevalent NON PCV13 serotypes based on local epidemiological data. This database served as a foundation for developing unsupervised models utilizing MALDI-TOF MS spectra, which enabled us to identify inherent patterns and relationships within the data. Our analysis involved a dataset comprising 215 new isolates collected from nationwide surveillance in Argentina. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates. Results: Although our findings revealed suboptimal performance in serotype classification, they provide valuable insights into the potential of machine learning algorithms in this context. The sensitivity of the models ranged from 0.41 to 0.46, indicating their ability to detect certain serotypes. The observed specificity consistently remained at 0.60, suggesting a moderate level of accuracy in identifying non-vaccine serotypes. These results highlight the need for further refinement and optimization of the algorithms to enhance their discriminative power and predictive accuracy in serotype identification.By addressing the limitations identified in this study, such as exploring alternative feature selection techniques or optimizing algorithm parameters, we can unlock the full potential of machine learning in robust and reliable serotype classification of S. pneumoniae. Our work not only provides a comprehensive evaluation of multiple machine learning models but also emphasizes the importance of considering their strengths and limitations. Conclusion: Overall, our study contributes to the growing body of research on utilizing MALDI-TOF MS and machine learning algorithms for serotype identification purposes.

Bactericidal killing of meningococcal W strains isolated in Argentina by the sera of adolescents and infants immunized with 4-component meningococcal serogroup B vaccine (4CMenB).

Invasive meningococcal disease (IMD) is a life-threatening disease caused by meningococcal serogroups A, B, C, W, X, and Y, of which B and W are most common in Argentina. The 4-component meningococcal serogroup B (4CMenB) vaccine contains three purified recombinant protein antigens (Neisseria adhesin A [NadA], factor H binding protein [fHbp], and Neisserial Heparin Binding Antigen [NHBA]) and outer membrane vesicles (OMV), which is derived from the New Zealand epidemic strain and contains Porin A 1.4. These antigens are present and conserved in strains that belong to other serogroups. In this study, we show that 10/11 (91%) meningococcal serogroup W (MenW) strains selected to be representative of MenW isolates that caused IMD in Argentina during 2010-2011 were killed in bactericidal assays by the sera of adolescents and infants who had been immunized with the 4CMenB vaccine. We also show that MenW strains that caused IMD in Argentina during 2018-2021 were genetically similar to the earlier strains, indicating that the 4CMenB vaccine would likely still provide protection against current MenW strains. These data highlight the potential of 4CMenB vaccination to protect adolescents and infants against MenW strains that are endemic in Argentina.

Laboratory surveillance of invasive Haemophilus influenzae disease in Argentina, 2011-2019

Abstract The incorporation of Haemophilus influenzae type b (Hib) vaccine into the Argentine National Immunization Program in 1998 resulted in a dramatic decrease in the incidence of invasive disease due to this serotype. We assessed 1405 H. influenzae (Hi) isolates causing invasive infections referred to the National Reference Laboratory between 2011 and 2019. Non-encapsulated Hi were the most common strains (44.5%), followed by types b (41.1%) and a (10.0%). Significant increase in the proportion of type b was observed, from 31.2% in 2011, to 50% in 2015, correlating with the peak incidence rate, later decreasing to 33.6% by 2019. We compared the genetic relationship between clones circulating during the period of increased Hib incidence (2011-2015) and those of the prevaccination-transition period (1997-1998). Four pulsotypes predominated in both periods, G, M, P and K, G being the most common. Multilocus sequence typing revealed that the 4 pulsotypes belonged to ST6, or one of its simple or double locus variants. Isolates from fully vaccinated individuals did not differ from those of the rest of the population studied. After ruling out aspects associated with emergence of specific clones, we concluded that factors such as low booster coverage rates, delayed vaccination schedules and use of different vaccines may have contributed to the reemergence of Hib infections.

Resumen La introducción de la vacuna contra Haemophilus influenzae tipo b (Hib) en el Programa Nacional de Inmunización de Argentina en 1998 produjo una drástica disminución de la incidencia de enfermedad invasiva causada por este serotipo. En el Laboratorio Nacional de Referencia se estudiaron 1405 aislamientos de H. influenzae causantes de enfermedad invasiva recibidos en el período 2011-2019. H. influenzae no capsulado fue el más frecuente (44,5%), seguido por los tipos b (41,1%) y a (10,0%). Se observó un aumento significativo de la proporción del tipo b, de 31,2% en 2011 a 50% en 2015, que se correlacionó con un pico de incidencia en ese mismo año. Hacia 2019, descendió a 33,6%. Con el objetivo de evaluar los clones circulantes durante el incremento de la proporción de Hib y comparar con el período prevacunal-transición, se determinó la relación genética de una selección de aislamientos de los períodos 1997-1998 y 2011-2015. El análisis por PFGE mostró 4 pulsotipos predominantes en los 2 períodos, G, M, P y K, y el pulsotipo G fue mayoritario en ambos períodos. Por MLST se demostró que los 4 pulsotipos pertenecieron al ST6 o sus variantes (simple o doble locus). Entre los aislamientos de pacientes con vacunación completa no se hallaron clones diferentes respecto del resto de la población. Se postula que las coberturas de vacunación no satisfactorias en las dosis de refuerzo, los esquemas atrasados y el uso de diferentes vacunas pudieron haber contribuido a la reemergencia de Hib.

Laboratory surveillance of invasive Haemophilus influenzae disease in Argentina, 2011-2019.

The incorporation of Haemophilus influenzae type b (Hib) vaccine into the Argentine National Immunization Program in 1998 resulted in a dramatic decrease in the incidence of invasive disease due to this serotype. We assessed 1405 H. influenzae (Hi) isolates causing invasive infections referred to the National Reference Laboratory between 2011 and 2019. Non-encapsulated Hi were the most common strains (44.5%), followed by types b (41.1%) and a (10.0%). Significant increase in the proportion of type b was observed, from 31.2% in 2011, to 50% in 2015, correlating with the peak incidence rate, later decreasing to 33.6% by 2019. We compared the genetic relationship between clones circulating during the period of increased Hib incidence (2011-2015) and those of the prevaccination-transition period (1997-1998). Four pulsotypes predominated in both periods, G, M, P and K, G being the most common. Multi-locus sequence typing revealed that the 4 pulsotypes belonged to ST6, or one of its simple or double locus variants. Isolates from fully vaccinated individuals did not differ from those of the rest of the population studied. After ruling out aspects associated with emergence of specific clones, we concluded that factors such as low booster coverage rates, delayed vaccination schedules and use of different vaccines may have contributed to the reemergence of Hib infections.

Invasive Streptococcus pneumoniae isolates from pediatric population in Argentina for the period 2006-2019. Temporal progression of serotypes distribution and antibiotic resistance.

Streptococcus pneumoniae is a major cause of severe invasive disease associated with high mortality and morbidity worldwide. A total of 2908 pneumococcal isolates were analyzed between 2006 and 2019. Gold standard pneumococcal serotyping (the Neufeld-Quellung reaction) was performed to identify the serotypes associated with infection in children < 5 years in Argentina and agar dilution method was carried out to determine their profiles to 14 antimicrobial agents. In 2012, the 13-valent pneumococcal conjugate vaccine (PCV13) was included in the National Immunization Program. In this work we have analyzed the local epidemiology of invasive pneumococcal diseases before and after the introduction of this vaccine in order to understand the epidemiological relevance and impact of PCV13. During the periods compared in the present study there was a significant increase in the proportion of non-PCV13 serotypes, serogroup 24 (246.7%) and 12F (85.7%), and a significant decrease in PCV13 serotypes, including serotypes 14 (91.2%), 5 (95.6%) and 1 (84.6%) among others. Another observation was that serotypes 3 (7.4%) and 19A (4.9%) still remain among the most frequent serotypes despite being part of the PCV13 formulation. Regarding antimicrobial resistance, in the present study we observed an increase in erythromycin resistance during the period of study mainly associated to serotype 14 in the pre-PCV13 period and to serogroup 24 in the post-PCV13 period, which also was the major NVT serotype associated with antimicrobial resistance and MDR. Serotypes 14, 24A/B/F and 19A were in the first three places among isolates resistant to all the antibiotics tested. Our data highlight the importance of continuous surveillance to assess the impact of pneumococcal vaccines and the use of antibiotics in the dynamic of pneumococcal serotypes.

Distribution of PCV13 and PPSV23 Streptococcus pneumoniae serotypes in Argentinean adults with invasive disease, 2013-2017 / Distribución de los serotipos PCV13 y PPSV23 de Streptococcus pneumoniae en adultos argentinos con enfermedad invasiva, 2013-2017

Abstract Streptococcus pneumoniae is a major cause of severe invasive disease associated with high mortality and morbidity worldwide. To identify the serotypes most commonly associated with infection in adults in Argentina, 791 pneumococcal isolates from 56 hospitals belonging to 16 provinces and Buenos Aires city were serotyped. The isolates were submitted as part of a National Surveillance Program for invasive pneumococcal disease in adults, which started in 2013. Serotypes 3, 8, 12F, 7F and 1 were the most prevalent among adult patients. During the study period there was no significant difference in serotype distribution between the age groups studied (18-64 and >65 years old), except for serotype 1, 3 and 23A. Most prevalent serotypes in pneumonia were serotype 7F, 1, 12F, 8, and 3. When the clinical diagnosis was meningitis, serotype 3 and 12F were the most prevalent, whereas when the diagnosis was sep-sis/bacteremia the most prevalent was serotype 8. In this work, for the 18-64-year-old group, PPSV23 and PCV13 serotypes accounted for 74.56% and 44.54% respectively of the cases in the studied period. On the other hand, for the >65-year-old group, these serotypes represented 72.30% and 41.42% respectively. The aim of this work was to establish the knowledge bases of the serotypes that cause invasive pneumococcal diseases in the adult population in Argentina and to be able to detect changes in their distribution over time in order to explore the potential serotype coverage of the vaccines in current use.

Resumen Streptococcus pneumoniae es una causa importante de enfermedad invasiva grave asociada con una alta mortalidad y morbilidad en todo el mundo. Para identificar los serotipos principales asociados con la infección en adultos en Argentina, 791 aislamientos de neumococo de 56 hospitales pertenecientes a 16 provincias y la ciudad de Buenos Aires fueron serotipificados. Los aislamientos fueron remitidos como parte del Programa Nacional de Vigilancia para la enfermedad neumocócica invasiva en adultos, que comenzó en 2013. Los serotipos 3, 8, 12F, 7F y 1 fueron los más prevalentes. Durante el período de estudio no hubo diferencias significativas en la distribución de serotipos entre los dos grupos de adultos estudiados (18-64 y >65 años), excepto para los serotipos 1, 3 y 23A. Los serotipos más prevalentes en casos de neumonía fueron 7F, 1, 12F, 8 y 3. Cuando el diagnóstico clínico fue meningitis, los serotipos 3 y 12F fueron los más prevalentes. Y el serotipo 8 fue el más prevalente en la sepsis/bacteriemia. En el grupo de 18-64 años, los serotipos PPSV23 y PCV13 representaron, respectivamente, el 74,56 y el 44,54% de los casos de enfermedad invasiva en el período estudiado. En el grupo de >65 años, estos serotipos representaron el 72,30 y 41,42%, respectivamente. Es importante conocer los serotipos causantes de infecciones neumocócicas invasivas en la población adulta en Argentina y detectar eventuales cambios en su distribución a lo largo del tiempo, para explorar la potencial cobertura de las vacunas utilizadas.

Distribution of PCV13 and PPSV23 Streptococcus pneumoniae serotypes in Argentinean adults with invasive disease, 2013-2017.

Streptococcus pneumoniae is a major cause of severe invasive disease associated with high mortality and morbidity worldwide. To identify the serotypes most commonly associated with infection in adults in Argentina, 791 pneumococcal isolates from 56 hospitals belonging to 16 provinces and Buenos Aires city were serotyped. The isolates were submitted as part of a National Surveillance Program for invasive pneumococcal disease in adults, which started in 2013. Serotypes 3, 8, 12F, 7F and 1 were the most prevalent among adult patients. During the study period there was no significant difference in serotype distribution between the age groups studied (18-64 and ≥65 years old), except for serotype 1, 3 and 23A. Most prevalent serotypes in pneumonia were serotype 7F, 1, 12F, 8, and 3. When the clinical diagnosis was meningitis, serotype 3 and 12F were the most prevalent, whereas when the diagnosis was sepsis/bacteremia the most prevalent was serotype 8. In this work, for the 18-64-year-old group, PPSV23 and PCV13 serotypes accounted for 74.56% and 44.54% respectively of the cases in the studied period. On the other hand, for the ≥65-year-old group, these serotypes represented 72.30% and 41.42% respectively. The aim of this work was to establish the knowledge bases of the serotypes that cause invasive pneumococcal diseases in the adult population in Argentina and to be able to detect changes in their distribution over time in order to explore the potential serotype coverage of the vaccines in current use.

Absceso cerebral por Haemophilus influenzae serotipo e en un paciente pediátrico con Síndrome de Apert / Brain abscess caused by Haemophilus influenzae type e in a pediatric patient suffering from Apert syndrome

Se presenta el caso de un absceso cerebral causado por Haemophilus infl uenzae tipo e, en un paciente de 12 años con síndrome de Apert. El síndrome de Apert se caracteriza por el cierre prematuro de las suturas craneales. En 2010, el paciente presentó traumatismo craneano en región frontal, fractura y fístula de líquido cefalorraquídeo. En febrero de 2013 consultó por fi ebre, vómitos y convulsión tónica clónica generalizada, con deterioro progresivo del sensorio. La tomografía axial computarizada mostró una lesión frontal derecha, edema perilesional, leve dilatación ventricular y pansinusitis. Se diagnosticó absceso cerebral con pioventriculitis y se realizó drenaje. Se obtuvo desarrollo de un cocobacilo gram negativo, que fue identifi cado como H. infl uenzae serotipo e. Se realizó tratamiento empírico con meropenem (120 mg/kg/día) y vancomicina (60 mg/kg/día). Luego del resultado del cultivo, se rotó a ceftriaxona (100 mg/kg/día) y metronidazol (500 mg/8 h). El paciente cumplió 8 semanas de tratamiento y se observó evolución favorable

We report a case of a brain abscess caused by Haemophilus infl uenzae type e in a 12 year-old patient suffering from Apert syndrome. Apert syndrome is characterized by the premature closure of cranial sutures. In 2010 the patient suffered head trauma in the frontal area with cranial fracture and a cerebrospinal fl uid fi stula. In February 2013 he was admitted to hospital with fever, vomiting and generalized tonic-clonic seizure with deteriorating mental status/progressive sensory impairment. The computerized axial tomographic scan showed a right frontal lesion, perilesional edema, mild ventricular dilatation and pansinusitis. A brain abscess was diagnosed and drained. The clinical sample was then cultured. A gram negative coccobacillus was isolated and identifi ed as Haemophilus infl uenzae serotype e. Empirical treatment was started with meropenem (120 mg/kg/day) and vancomycin (60 mg/kg/day), which was later switched to ceftriaxone (100 mg/kg/day) and metronidazole (500 mg/8 h) after culture results arrived. The patient was discharged in good clinical condition

[Brain abscess caused by Haemophilus influenzae type E in a pediatric patient suffering from Apert syndrome]. / Absceso cerebral por Haemophilus influenzae serotipo e en un paciente pediátrico con síndrome de Apert.

We report a case of a brain abscess caused by Haemophilus influenzae type e in a 12 year-old patient suffering from Apert syndrome. Apert syndrome is characterized by the premature closure of cranial sutures. In 2010 the patient suffered head trauma in the frontal area with cranial fracture and a cerebrospinal fluid fistula. In February 2013 he was admitted to hospital with fever, vomiting and generalized tonic-clonic seizure with deteriorating mental status/progressive sensory impairment. The computerized axial tomographic scan showed a right frontal lesion, perilesional edema, mild ventricular dilatation and pansinusitis. A brain abscess was diagnosed and drained. The clinical sample was then cultured. A gram negative coccobacillus was isolated and identified as Haemophilus influenzae serotype e. Empirical treatment was started with meropenem (120 mg/kg/day) and vancomycin (60 mg/kg/day), which was later switched to ceftriaxone (100 mg/kg/day) and metronidazole (500 mg/8 h) after culture results arrived. The patient was discharged in good clinical condition.

Absceso cerebral por Haemophilus influenzae serotipo e en un paciente pediátrico con síndrome de Apert. / [Brain abscess caused by Haemophilus influenzae type e in a pediatric patient suffering from Apert syndrome].

We report a case of a brain abscess caused by Haemophilus influenzae type e in a 12 year-old patient suffering from Apert syndrome. Apert syndrome is characterized by the premature closure of cranial sutures. In 2010 the patient suffered head trauma in the frontal area with cranial fracture and a cerebrospinal fluid fistula. In February 2013 he was admitted to hospital with fever, vomiting and generalized tonic-clonic seizure with deteriorating mental status/progressive sensory impairment. The computerized axial tomographic scan showed a right frontal lesion, perilesional edema, mild ventricular dilatation and pansinusitis. A brain abscess was diagnosed and drained. The clinical sample was then cultured. A gram negative coccobacillus was isolated and identified as Haemophilus influenzae serotype e. Empirical treatment was started with meropenem (120 mg/kg/day) and vancomycin (60 mg/kg/day), which was later switched to ceftriaxone (100 mg/kg/day) and metronidazole (500 mg/8 h) after culture results arrived. The patient was discharged in good clinical condition.

Vigilancia de serotipos en infecciones invasivas por Haemophilus influenzae en la Argentina en la era de la vacuna conjugada contra el serotipo b durante el período 2005-2010 / Surveillance of Haemophilus influenzae serotypes in Argentina from 2005 to 2010 during the Haemophilus influenzae type b conjugate vaccine era

La introducción de la vacuna contra Haemophilus influenzae tipo b en los programas de inmunización de muchos países produjo una reducción marcada en la incidencia de enfermedad invasiva causada por este serotipo y en su portación y un incremento de otros tipos capsulares y de aislamientos no capsulados. Se estudiaron 313 aislamientos de H. influenzae recuperados de sitio estéril, provenientes de pacientes pediátricos y adultos con enfermedad invasiva atendidos en 90 hospitales de la Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas durante el período 2005-2010. Las patologías más frecuentes fueron neumonía, 40,3 % (n = 126), meningitis, 30,0 % (n = 94) y bacteriemia, 26,5 % (n = 83). En los pacientes pediátricos (n = 279), la mayor frecuencia de aislamientos correspondió a menores de 2 años, 74,5 % (n = 208). Con respecto a la distribución de tipos, el 61,3 %, correspondió a H. influenzae no capsulados (n = 192); el 20,1 % al b (n = 63); 11,2 % al a (n = 35); 4,8 % al f y 2,6 % a otros. En meningitis predominaron H. influenzae capsulados mientras que en neumonía y bacteriemia resultaron dominantes los tipos no capsulados. Se determinó el biotipo en 306 aislamientos. Todos los aislamientos de tipo a correspondieron al biotipo II; el 66,7 % de los tipo b pertenecieron al biotipo I. Mediante las técnicas de aglutinación en lámina y PCR se estudiaron 220 aislamientos; la concordancia entre ambas fue de 0,982 (IC: 0,92-1,00). En el último año se encontró un aumento significativo del tipo b, lo cual indica la importancia de mantener la vigilancia clínica y laboratorial de la enfermedad invasiva por H. influenzae.

The introduction of the Haemophilus influenzae type b vaccine in the immunization programs of many countries has greatly reduced this invasive disease and the carriage caused by this serotype, also increasing other capsular types and non-capsular isolations. There were 313 isolations of H. influenzae under study, which were recovered from a sterile site coming from pediatric and adult patients carrying the invasive disease. Patients were treated at 90 different hospitals belonging to the Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas (National Lab Network for Meningitis and Acute Bacterial Respiratory Infections) from 2005 to 2010 for the following disorders: pneumonia, 40.3% (n = 126), meningitis, 30.0% (n = 94) and bacteremia, 26.5% (n = 83). In pediatric patients (n = 279), the highest frequency of isolations corresponded to children under the age of 2 years, 74.5% (n = 208). Regarding type distribution, 61.3% corresponded to non-capsular H. influenzae (n = 192), 20.1% to type b (n = 63), 11.2% to type a (n = 35), 4.8% to type f, and 2.6% to other types. Capsular H. influenzae was predominant in meningitis whereas non-capsular H. influenzae in pneumonia and bacteremia. The biotype was determined in 306 isolations. The totality (100%) of type a (n = 35) was biotype II whereas 66.7% of type b (n = 63) was biotype I. Slide agglutination and PCR tests were used in 220 isolations. There was a match of 0.982 (IC: 0.92-1.00) between them. During the last year, there was a great increase in type b, showing the importance of clinical and laboratory-based surveillance of the invasive disease caused by H. influenzae.

Vigilancia de serotipos en infecciones invasivas por Haemophilus influenzae en la Argentina en la era de la vacuna conjugada contra el serotipo b durante el período 2005-2010 / Surveillance of Haemophilus influenzae serotypes in Argentina from 2005 to 2010 during the Haemophilus influenzae type b conjugate vaccine era

La introducción de la vacuna contra Haemophilus influenzae tipo b en los programas de inmunización de muchos países produjo una reducción marcada en la incidencia de enfermedad invasiva causada por este serotipo y en su portación y un incremento de otros tipos capsulares y de aislamientos no capsulados. Se estudiaron 313 aislamientos de H. influenzae recuperados de sitio estéril, provenientes de pacientes pediátricos y adultos con enfermedad invasiva atendidos en 90 hospitales de la Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas durante el período 2005-2010. Las patologías más frecuentes fueron neumonía, 40,3 % (n = 126), meningitis, 30,0 % (n = 94) y bacteriemia, 26,5 % (n = 83). En los pacientes pediátricos (n = 279), la mayor frecuencia de aislamientos correspondió a menores de 2 años, 74,5 % (n = 208). Con respecto a la distribución de tipos, el 61,3 %, correspondió a H. influenzae no capsulados (n = 192); el 20,1 % al b (n = 63); 11,2 % al a (n = 35); 4,8 % al f y 2,6 % a otros. En meningitis predominaron H. influenzae capsulados mientras que en neumonía y bacteriemia resultaron dominantes los tipos no capsulados. Se determinó el biotipo en 306 aislamientos. Todos los aislamientos de tipo a correspondieron al biotipo II; el 66,7 % de los tipo b pertenecieron al biotipo I. Mediante las técnicas de aglutinación en lámina y PCR se estudiaron 220 aislamientos; la concordancia entre ambas fue de 0,982 (IC: 0,92-1,00). En el último año se encontró un aumento significativo del tipo b, lo cual indica la importancia de mantener la vigilancia clínica y laboratorial de la enfermedad invasiva por H. influenzae.(AU)

The introduction of the Haemophilus influenzae type b vaccine in the immunization programs of many countries has greatly reduced this invasive disease and the carriage caused by this serotype, also increasing other capsular types and non-capsular isolations. There were 313 isolations of H. influenzae under study, which were recovered from a sterile site coming from pediatric and adult patients carrying the invasive disease. Patients were treated at 90 different hospitals belonging to the Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas (National Lab Network for Meningitis and Acute Bacterial Respiratory Infections) from 2005 to 2010 for the following disorders: pneumonia, 40.3% (n = 126), meningitis, 30.0% (n = 94) and bacteremia, 26.5% (n = 83). In pediatric patients (n = 279), the highest frequency of isolations corresponded to children under the age of 2 years, 74.5% (n = 208). Regarding type distribution, 61.3% corresponded to non-capsular H. influenzae (n = 192), 20.1% to type b (n = 63), 11.2% to type a (n = 35), 4.8% to type f, and 2.6% to other types. Capsular H. influenzae was predominant in meningitis whereas non-capsular H. influenzae in pneumonia and bacteremia. The biotype was determined in 306 isolations. The totality (100%) of type a (n = 35) was biotype II whereas 66.7% of type b (n = 63) was biotype I. Slide agglutination and PCR tests were used in 220 isolations. There was a match of 0.982 (IC: 0.92-1.00) between them. During the last year, there was a great increase in type b, showing the importance of clinical and laboratory-based surveillance of the invasive disease caused by H. influenzae.(AU)

[Surveillance of Haemophilus influenzae serotypes in Argentina from 2005 to 2010 during the Haemophilus influenzae type b conjugate vaccine era]. / Vigilancia de serotipos en infecciones invasivas por Haemophilus influenzae en la Argentina en la era de la vacuna conjugada contra el serotipo b durante el período 2005-2010.

The introduction of the Haemophilus influenzae type b vaccine in the immunization programs of many countries has greatly reduced this invasive disease and the carriage caused by this serotype, also increasing other capsular types and non-capsular isolations. There were 313 isolations of H. influenzae under study, which were recovered from a sterile site coming from pediatric and adult patients carrying the invasive disease. Patients were treated at 90 different hospitals belonging to the Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas (National Lab Network for Meningitis and Acute Bacterial Respiratory Infections) from 2005 to 2010 for the following disorders: pneumonia, 40.3% (n=126), meningitis, 30.0% (n=94) and bacteremia, 26.5% (n=83). In pediatric patients (n=279), the highest frequency of isolations corresponded to children under the age of 2 years, 74.5% (n=208). Regarding type distribution, 61.3% corresponded to non-capsular H. influenzae (n=192), 20.1% to type b (n=63), 11.2% to type a (n=35), 4.8% to type f, and 2.6% to other types. Capsular H. influenzae was predominant in meningitis whereas non-capsular H. influenzae in pneumonia and bacteremia. The biotype was determined in 306 isolations. The totality (100%) of type a (n=35) was biotype II whereas 66.7% of type b (n=63) was biotype I. Slide agglutination and PCR tests were used in 220 isolations. There was a match of 0.982 (IC: 0.92-1.00) between them. During the last year, there was a great increase in type b, showing the importance of clinical and laboratory-based surveillance of the invasive disease caused by H. influenzae.

Vigilancia de serotipos en infecciones invasivas por Haemophilus influenzae en la Argentina en la era de la vacuna conjugada contra el serotipo b durante el período 2005-2010. / [Surveillance of Haemophilus influenzae serotypes in Argentina from 2005 to 2010 during the Haemophilus influenzae type b conjugate vaccine era].

The introduction of the Haemophilus influenzae type b vaccine in the immunization programs of many countries has greatly reduced this invasive disease and the carriage caused by this serotype, also increasing other capsular types and non-capsular isolations. There were 313 isolations of H. influenzae under study, which were recovered from a sterile site coming from pediatric and adult patients carrying the invasive disease. Patients were treated at 90 different hospitals belonging to the Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas (National Lab Network for Meningitis and Acute Bacterial Respiratory Infections) from 2005 to 2010 for the following disorders: pneumonia, 40.3

(n=126), meningitis, 30.0

(n=94) and bacteremia, 26.5

(n=83). In pediatric patients (n=279), the highest frequency of isolations corresponded to children under the age of 2 years, 74.5

(n=208). Regarding type distribution, 61.3

corresponded to non-capsular H. influenzae (n=192), 20.1

to type b (n=63), 11.2

to type a (n=35), 4.8

to type f, and 2.6

to other types. Capsular H. influenzae was predominant in meningitis whereas non-capsular H. influenzae in pneumonia and bacteremia. The biotype was determined in 306 isolations. The totality (100

) of type a (n=35) was biotype II whereas 66.7

of type b (n=63) was biotype I. Slide agglutination and PCR tests were used in 220 isolations. There was a match of 0.982 (IC: 0.92-1.00) between them. During the last year, there was a great increase in type b, showing the importance of clinical and laboratory-based surveillance of the invasive disease caused by H. influenzae.

[Pediatric tuberculosis at a reference hospital during the 2004-2008 period]. / Tuberculosis pediátrica en un hospital de referencia durante el período 2004-2008.

Samples of pediatric patients suspected of tuberculosis and cared for at Hospital Piñero during the 2004-2008 period were analyzed according to epidemiological and clinical criteria. The bacteriological contribution was evaluated to confirm the disease diagnosis. A descriptive retrospective analysis of the cases was done. A total of 8409 samples were received for mycobacterial culture: 1542 (18%) of which were pediatric and distributed as follows: 1407 (91%), pulmonary and 135 (9%), extra-pulmonary. The sample examination included staining for acid-fast bacilli, culture, identification and drug susceptibility testing. The following are the results of analized demographic variables: Nationality: 1218 Argentinean (79%), 247 foreigners (16%) and 77, not disclosed (5%); Gender: 787 female (51%) and 755 male (49%). Patients were grouped according to age into: Group A, 0 to 4 years 674 (45%); Group B, 5-9 years 354 (24%) and Group C, 10-15 years 464 (31%). Morbidity causes associated with the disease were mainly malnutrition and infection by Human Immunodeficiency Virus. Staining for acid-fast bacilli was positive in 41 samples (2.6%) and 84 cultures resulted positive (5.4%), 78 (93%) of which were pulmonary and 6 (7%) extra-pulmonary samples. All the strains were identified as Mycobacterium tuberculosis. Isolates were susceptible to streptomycin, isoniazid, rifampicin, and ethambutol, except for one strain that was resistant both to ethambutol and streptomycin, and another one which was resistant to isoniazid. Bacteriological confirmation of pediatric tuberculosisis is rarely achieved due to the predominantly paucibacillary nature of the disease in children (5% in our study), but plays a fundamental role in diagnosis accuracy, allowing the identification and susceptibility testing of the strain.