Effect of coinfection with influenza virus and bacteria on host damage / Efecto de la coinfección por virus de la influenza y bacterias en el daño al hospedero

Abstract Background: Influenza virus infection is often complicated by a bacterial infection, with this coinfection causing severe pneumonia. If not timely treated, the disease can cause death. Objective: To demonstrate, in animal models, that coinfection with influenza virus and bacteria that affect the respiratory tract causes multisystemic damage. Method: Six groups of mice were formed: a control group, one infected with the influenza virus, two infected with bacteria: Haemophilus influenzae and Streptococcus pneumoniae, respectively; and two co-infected with influenza virus and Haemophilus influenzae or Streptococcus pneumoniae, respectively. Results: Of the six groups of mice, only the group co-infected with influenza virus and Streptococcus pneumoniae showed damage to thoracic and abdominal organs. A decrease in serum cytokine levels was found in all study groups, which was more pronounced in the co-infected mice. Conclusions: The groups of mice infected with Streptococcus pneumoniae or influenza virus alone showed no damage, which indicates that coexistence of these infections caused the damage in the group of co-infected mice.

Resumen Antecedentes: La infección por el virus de la influenza con frecuencia se complica con una infección bacteriana, coinfección que provoca cuadros graves de neumonía, la cual puede ocasionar la muerte si no es tratada en forma oportuna. Objetivo: Demostrar en modelos animales que la coinfección por el virus de la influenza y bacterias que afectan el tracto respiratorio ocasiona daño multisistémico. Método: Se formaron seis grupos de ratones: un grupo control, uno infectado de virus de la influenza, dos infectados de bacterias: Haemophilus influenzae y Streptococcus pneumoniae, respectivamente; y dos coinfectados de virus de la influenza y Haemophilus influenzae y Streptococcus pneumoniae, respectivamente. Resultados: De los seis grupos de ratones, solo en el grupo coinfectado de virus de la influenza y Streptococcus pneumoniae se observó daño en órganos torácicos y abdominales. En todos los grupos se encontró disminución de los niveles séricos de las citocinas, mayor en los ratones coinfectados. Conclusiones: Los grupos de ratones infectados solo de Streptococcus pneumoniae o el virus de la influenza no presentaron daños, lo cual indica que la coexistencia de estas infecciones fue la que ocasionó el daño en el grupo de ratones coinfectados.

Invasive non-type b haemophilus influenzae disease: report of eight cases / Doença invasiva causada por haemophilus influenzae não tipo b: relato de oito casos

ASTRACT Objective: To describe eight cases of invasive non-type b Haemophilus influenzae disease in children admitted to Hospital de Clínicas of Universidade Estadual de Campinas. Cases description: In 2015, there were eight cases of invasive non-type b H. influenzae disease. We tested the ampicillin sensitivity and beta-lactamase production of the strains identified and performed the genotyping. Molecular typing was determined by Pulsed-Field Gel Electrophoresis. Four patients were diagnosed with bacteremia; in two cases, H. influenzae was detected in the pleural fluid, and two patients had meningitis. Patients with comorbidities represented 37.5% of cases. Except for the strain of one patient - not sent to the reference laboratory -, all were ampicillin-sensitive and non-beta-lactamase-producing. Genotyping identified four non-capsular, one type c, and two type a strains. Molecular typing ruled out nosocomial transmission since all serotypes were distinct regarding genotype. Comments: The rise in cases of invasive non-type b H. influenzae infection was real. There was no nosocomial transmission, and we found no justification for the increase. These data indicate the need for surveillance to correctly diagnose, monitor, and understand the spectrum of non-type b H. influenzae disease.

ABSTRACT Objetivo: Descrever oito casos de doença invasiva por Haemophilus influenzae não tipo b em crianças internadas no Hospital de Clínicas da Universidade Estadual de Campinas. Descrição dos casos: Em 2015, ocorreram oito casos de doença invasiva por H. influenzae não tipo b. Nas cepas identificadas, testou-se a sensibilidade à ampicilina e a produção de betalactamase, e realizou-se a genotipagem. A tipagem molecular foi feita por Pulsed Field Gel Electrophoresis. Em quatro pacientes, o diagnóstico foi de bacteremia; em dois casos, H. influenzae foi identificado em líquido pleural, e dois pacientes tiveram meningite. Comorbidades foram encontradas em 37,5% dos pacientes. Com exceção da cepa de um dos pacientes (que não foi enviada ao laboratório de referência), todas eram sensíveis à ampicilina e não produtoras de betalactamase. A genotipagem identificou quatro cepas não capsulares, uma cepa tipo c e duas cepas tipo a. A tipagem molecular descartou a transmissão intra-hospitalar, já que todos os sorotipos eram distintos quanto ao genótipo. Comentários: O aumento dos casos de infecção invasiva por H. influenzae não tipo b foi real. Não houve transmissão intra-hospitalar e não foi encontrada justificativa para o aumento. Esses dados indicam a necessidade de vigilância para diagnosticar corretamente, monitorar e entender o espectro da doença causada por H. influenzae não tipo b.

Haemophilus influenzae no tipificable: mecanismo de destrucción del biofilm / Non-typeable Haemophilus influenzae: mechanism of biofilm destruction

INTRODUCCIÓN: Haemophilus influenzae tiene como hábitat el aparato respiratorio humano. No existe vacuna contra la variante no tipificable (NTHi) de este, por lo que se ha mostrado una tendencia al incremento de casos en los últimos años. La patogenicidad de NTHi se debe a su habilidad para formar biofilms, por lo que se pretende analizar mecanismos de destrucción del biofilm formado por NTHi. METODOLOGÍA: Se realizó una revisión bibliográfica mediante consultas en las bases de datos, Hinari, MEDLINE y el motor de búsqueda PubMed. Se tomaron en consideración artículos originales, ensayos clínicos y artículos de revisión bibliográfica dando prioridad a aquellos publicados en los últimos 5 años. DESARROLLO: NTHi tiene la capacidad de formar biofilms por medio de proteínas del pili y elementos estabilizadores del ADN extracelular, entre los más importantes están: DNA BII, pili tipo IV, Nucleasa extracelular 2019 y adhesinas de alto peso molecular. El uso de chalconas, EDTA y ADN como quelante de cationes, antisueros contra DNBII y maquinaria luxS más anticuerpos contra Pili IV han demostrado que pueden ser útiles para la erradicación del biofilm. CONCLUSIÓN: Se proponen dos tratamientos novedosos que podrían contribuir en la eliminación del biofilm formado por NTHi, uno es el uso de EDTA y otro los anticuerpos dirigidos a proteínas esenciales en la formación y adhesión del biofilm. Es necesario profundizar en otros estudios con estas propuestas terapéuticas para determinar su uso en el área clínica en un futuro.

INTRODUCTION: Haemophilus influenzae has the human respiratory system as habitat. There's no vaccine against the non-typeable group (NTHi), as a consequence there has been an increase in the number of cases in the past few years. The pathogenesis of NTHi is caused by its ability to form biofilms, for this reason we pretend to analyze the destruction mechanisms of biofilms formed by NTHi. METHODOLOGY: A review was made using the databases Hinari, MEDLINE and PubMed. Original articles, clinical trials and reviews that had been published in the last five years were taken in count. RESULTS: NTHi has the capacity to form biofilms through pilus proteins and extracellular DNA stabilizers; among the most important we have: DNA BII, type IV pilus, 2019 extracellular nuclease and adhesins of high molecular weight. The use of chalcone, EDTA, DNA as cation chelant, antiserum against DNA BII and luxS plus antibodies against Pili IV has shown potential to eradicate biofilms. DISCUSSION: Two new treatments, that could contribute to the removal of biofilms formed by NTHi, are proposed: one of them is the use of EDTA and the other one is the use of antibodies against essential proteins that the bacteria uses in the formation and adhesion of biofilms. Never the less, it is necessary to deepen more in studies about these therapeutic alternatives to determine their use in the clinical area in the future.

Invasive Haemophilus influenzae disease in the vaccine era in Rio de Janeiro, Brazil

BACKGROUND Haemophilus influenzae (Hi) serotype b (Hib) conjugate vaccine was incorporated into the infant immunisation schedule in Brazil in 1999, where Hib was one of the major etiologic sources of community-acquired bacterial meningitis. OBJECTIVES The purpose of this study is to describe the molecular epidemiology of invasive Hi disease in Rio de Janeiro state, Brazil, before and after vaccine introduction. METHODS Surveillance data from 1986 to 2014 were analysed. Hi isolates recovered from cerebrospinal fluid (CSF) or blood from 1993 to 2014 were serotyped by slide agglutination, genotyped by multilocus sequence typing (MLST), and the capsule type evaluation, differentiation of serologically non-typeable isolates, and characterisation of the capsule (cap) locus was done by polymerase chain reaction. Antimicrobial susceptibility testing was performed using E-test. FINDINGS From 1986 to 1999 and from 2000 to 2014, 2580 and 197 (42% without serotype information) confirmed cases were reported, respectively. The case fatality rate was 17% and did not correlate with the strain. Hib and b- variant isolates belonged to ST-6, whereas serotype a isolates belonged to the ST-23 clonal complex. Serotype a appeared to emerge during the 2000s. Non-encapsulated isolates were non-clonal and distinct from the encapsulated isolates. Ampicillin-resistant isolates were either of serotype b or were non-encapsulated, and all of them were β-lactamase-positive but amoxicillin-clavulanic acid susceptible. MAIN CONCLUSIONS Although Hi meningitis became a relatively rare disease in Rio de Janeiro after the introduction of the Hib conjugate vaccine, the isolates recovered from patients have become more diverse. These results indicate the need to implement an enhanced surveillance system to continue monitoring the impact of the Hib conjugate vaccine.

Inflammatory response of Haemophilus influenzae biotype aegyptius causing Brazilian Purpuric Fever

The Brazilian Purpuric Fever (BPF) is a systemic disease with many clinical features of meningococcal sepsis and is usually preceded by purulent conjunctivitis. The illness is caused by Haemophilus influenza biogroup aegyptius, which was associated exclusively with conjunctivitis. In this work construction of the las gene, hypothetically responsible for this virulence, were fusioned with ermAM cassette in Neisseria meningitidis virulent strains and had its DNA transfer to non BPF H. influenzae strains. The effect of the las transfer was capable to increase the cytokines TNFα and IL10 expression in Hec-1B cells line infected with these transformed mutants (in eight log scale of folding change RNA expression). This is the first molecular study involving the las transfer to search an elucidation of the pathogenic factors by horizontal intergeneric transfer from meningococci to H. influenzae.

Multi locus sequence type comparison of invasive and commensal Haemophilus influenzae isolates from Delhi.

Haemophilus influenzae is a major public health concern in the developing world. The most virulent strain is H. influenzae Type b (Hib). Hib also constitutes a major portion of nasopharyngeal commensal flora in otherwise healthy individuals. Through dendogram based on composite gene sequences of seven multi locus sequence type genes, it was observed that invasive and commensal isolates made two completely separate clusters which are indicative of independent evolution of these two groups of H. influenzae in the Indian subcontinent.

Endocardite infecciosa por Haemophilus aphrophilus: relato de caso / Infective endocarditis due to Haemophilus aphrophilus: a case report

OBJETIVO: Descrever o caso de uma criança com endocardite infecciosa causada por Haemophilus aphrophilus. DESCRIÇÃO: Menino com febre e calafrios há 20 dias. À internação, apresentava-se febril, descorado e sem sinais de instabilidade hemodinâmica; à ausculta cardíaca, tinha sopro holosistólico em foco mitral. Os exames laboratoriais identificaram anemia (hemoglobina = 9,14 g/dL), leucócitos totais de 11.920 mm³, plaquetas de 250.000 mm³, velocidade de sedimentação das hemácias e proteína C reativa elevadas. O ecocardiograma revelou imagem em válvula mitral, sugestiva de vegetação. Com a hipótese de endocardite, foi iniciada antibioticoterapia com penicilina cristalina (200.000 UI/kg/dia) associada à gentamicina (4 mg/kg/dia). No terceiro dia de tratamento, foi identificado Haemophilus aphrophilus em hemoculturas, sendo então trocado o esquema antibiótico para ceftriaxona (100 mg/kg/dia). No 20º dia de internação, encontrava-se pálido, mas sem febre e sem outras queixas. Os exames mostravam hemoglobina = 7,0 g/dL, leucócitos = 2.190 mm³, plaquetas = 98.000 mm³, razão normatizada internacional = 1,95 e R = 1,89. Foi feita hipótese de reação adversa ao ceftriaxona, que foi substituído por ciprofloxacina, 20 mg/kg/dia, até completar 6 semanas de tratamento. Após 72 horas da troca, houve normalização dos exames. Durante seguimento ambulatorial, apresentou insuficiência mitral grave, sendo submetido a troca de válvula por prótese metálica 9 meses após quadro agudo. Há 3 anos encontra-se bem, em acompanhamento ambulatorial. COMENTÁRIOS: É rara a identificação de agentes do grupo HACEK (Haemophilus ssp, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens e Kingella kingae) em crianças com endocardite infecciosa. O caso apresentado, sem fatores de risco relacionados a esses agentes, reafirma a necessidade de tentar sempre identificar o agente etiológico das endocardites para adequação do tratamento.

OBJECTIVE: To report the case of a child with infective endocarditis caused by Haemophilus aphrophilus. DESCRIPTION: Boy with 20 days of fever and chills. On admission, he was febrile, pale and with no signs of hemodynamic instability; on cardiac auscultation, a mitral-related holosystolic murmur was observed. Laboratory examination identified anemia (hemoglobin = 9.14 g/dL), total leukocytes of 11,920 mm³, platelets of 250,000 mm³, elevated sedimentation velocity of red cells and elevated C-reactive protein. The echocardiogram revealed image on mitral valve, resembling vegetation. Considering endocarditis, antibiotic therapy was started with crystalline penicillin (200,000 UI/kg/day) in association with gentamicin (4 mg/kg/day). On the third day of treatment, Haemophilus aphrophilus was identified in the blood cultures and the antibiotic scheme was replaced with ceftriaxone (100 mg/kg/day). On the 20th day of evolution, the patient was pale but with no fever or other complaints. Examinations showed hemoglobin = 7.0 g/dL, leukocytes = 2,190 mm³, platelets = 98,000 mm³, international normalized ratio = 1.95 and R = 1.89. Considering the hypothesis of adverse reaction to ceftriaxone, a 6-week replacement treatment with ciprofloxacin (20 mg/kg/day) was started. Examination results normalized after 72 hours of the replacement therapy. During ambulatory follow-up, patient presented with severe mitral regurgitation, undergoing a valve replacement with a metallic prosthetic valve 9 months after acute event. Patient has done well throughout the 3-year ambulatory follow-up. COMMENTS: Identification of agents of the HACEK group (Haemophilus ssp, Actinobacillus actinomycetemcomitans,Cardiobacterium hominis, Eikenella corrodens and Kingella kingae) in children with infective endocarditis is rare. This case report, with no HACEK agent-related risk factors, reinforces the need for identification of the etiological agent of endocarditis to ensure adequate treatment.

Tipificación capsular mediante PCR de aislamientos de Haemophilus influenzae no tipificables por aglutinación / PCR-based capsular typing of Haemophilus influenzae isolates non-typeable by agglutination

Haemophilus influenzae es reconocido como un agente patógeno responsable de infecciones localizadas y sistémicas. Se han descrito 6 tipos de polisacáridos capsulares antigénicamente distintos (a, b, c, d, e, y f ) que se pueden identificar por aglutinación en lámina con antisueros específicos. También existen cepas no capsuladas (NC) fenotípicamente no tipificables (NT). La introducción de la vacuna conjugada produjo una marcada disminución de las enfermedades invasivas causadas por H. influenzae tipo b. En este contexto, la tipificación capsular mediante PCR es el método más apropiado para distinguir las cepas no capsuladas de las mutantes b deficientes en cápsula (b-) y detectar la presencia de cepas pertenecientes a otros serotipos que no puedan ser tipificables por aglutinación. Se determinó el genotipo capsular a 38 aislamientos de Haemophilus influenzae no tipificables por aglutinación, derivados al servicio de Bacteriología Clínica del INEI-ANLIS "Dr. Carlos G. Malbrán" en el período 2002-2004. El 78,9% de los aislamientos provenían de hemocultivos y la mayor parte de ellos estaban asociados a foco respiratorio. El 100% de los aislamientos fueron identificados como H. influenzae no capsulados mediante la técnica de PCR.

Haemophilus influenzae is recognized as a pathogenic agent responsible of localized and systemic infections. Six antigenically different capsular polysaccharide types have been described (a, b, c, d, e, and f ) which can be identified by slide agglutination with specific antisera. Besides there are non capsulated strains that cannot be typed by slide agglutination. The introduction of the conjugated vaccine produced an important reduction of invasive diseases caused by H. influenzae type b. Capsular typing by PCR is the most appropriated method for distinguishing non capsulated strains from capsule deficient type b mutants (b-) and for detecting strains of other serotypes that cannot be detected by slide agglutination. Capsular genotype was studied in 38 isolates of non-typeable Haemophilus influenzae received at INEIANLIS "Dr. Carlos G. Malbrán" between 2002-2004. Of the isolates included in this study 78.9% of them were recovered from blood cultures and most of them were associated with a respiratory focus. By PCR technique 100% of the isolates were identified as non-capsulate H. influenzae and genotype b-was not detected.

Microorganismos patógenos aislados en muestras respiratorias de niños con fibrosis quística / Isolated pathogen microorganisms in respiratory samples from children with cystic fibrosis

La fibrosis quística (FQ) se caracteriza por disfunciones en las glándulas de secreción exocrina del organismo. Las primeras manifestaciones suelen observarse en el sistema respiratorio, constituyendo una de las causas más importantes de morbimortalidad en los pacientes afectados. Los microorganismos patógenos que colonizan frecuentemente el tracto respiratorio de estos pacientes son Staphylococcus aureus, Haemophilus spp., y Pseudomonas aeruginosa. Entre noviembre de 2001 y agosto de 2004 se estudiaron 222 muestras respiratorias de pacientes con FQ de entre 4 meses y 11 años de edad. Se aislaron S. aureus (38,7%), P. aeruginosa (37,4%) y Haemophilus spp., (15,3%). En S. aureus la meticilina-resistencia fue del 25,9% y se asoció con altas resistencias a eritromicina (35,0%) y clindamicina (29,4%). El mayor porcentaje de resistencia observado en las cepas de P. aeruginosa fue frente a gentamicina (31,0%). Los aislamientos de Haemophilus spp. fueron resistentes a ampicilina (23,0%) debido a la presencia de beta-lactamasas, y a trimetoprima/sulfametoxazol (59,0%).

Cystic Fibrosis (CF) is characterized by a dysfunction of the exocrine secretion glands. The first symptoms often appear in the respiratory system which constitutes one of the most important morbimortality causes in these patients. Chronic respiratory tract colonization is caused mainly by bacteria such as Staphylococcus aureus, Haemophilus spp. and Pseudomonas aeruginosa. Respiratory samples from patients with CF (age group: 4 months to 11 years) were analyzed from November 2001 to August 2004. The most frequently isolated microorganisms were S. aureus (38.7%), P. aeruginosa (37.4%) and Haemophilus spp (15.3%). A high resistance to erithromycine (35.0%) and clindamicine (29.4%) was observed in S. aureus strains and 25.9% of them were methicillin-resistant. P. aeruginosa strains were mainly gentamicin-resistant (31.0%). The rate of ampicillin-resistant Haemophilus spp. was 23.0% and it was due to the presence of beta-lactamases, but a high trimethoprim-sulfamethoxazole resistance was observed in this microorganism (59.0%).

Neumonía grave causada por Haemophilus influenzae no tipificable en un lactante: Reporte de un caso / Non-typable Haemophilus influenzae severe pneumonia in an infant: Case report

Previo a la introducción de la vacuna conjugada, Haemophilus influenzae b (Hib) representó una de las causas importantes de neumonía en niños. Recientemente cepas no b y no tipificable (nt) han emergido como agentes importantes de enfermedad. Reportamos el caso de una lactante afectada por una neumonía consolidante extensa con empiema y bacteriémica, con el antecedente de haber recibido antes vacuna contra Hib. Los cultivos de sangre y líquido pleural revelaron la presencia de H. influenzae nt. La evolución clínica fue favorable, retirándose el drenaje pleural al segundo día. Fue tratada con cefotaxima endovenosa durante cinco días y luego 9 días de amoxicilina en forma ambulatoria. Se revisa la literatura acerca de esta inusual forma de presentación en nuestro medio y se advierte la emergencia de cepas no tipificables de H. influenzae como responsables de algunas formas graves de neumonía.

Aislamiento de distintos serotipos de Haemophilus influenzae en muestras profundas de pacientes pediátricos / Isolation of Haemophilus influenzae serotypes from sterile sites in sick children

Haemophilus influenzae (Hi) es responsable de diversas enfermedades humanas como sepsis, meningitis, celulitis y osteoartritis. En este trabajo se investigó la recuperación de distintos serotipos de Hi en muestras profundas de pacientes pediátricos. Se estudiaron 179 aislamientos de 146 niños durante el periodo 1996-2002 en el Laboratorio de Microbiología del Hospital de Niños Superiora Sor María Ludovica, Argentina. La distribución de los serotipos fue la siguiente: 1 a, 112 b, 1 c,1 d, 4 e, 3 f y 24 no tipificables. A partir del establecimiento de la estrategia de vacunación universal anti Hi b en 1998 se observa una disminución notable del serotipo b y un aumento relativo de otros y no tipificables.

Haemophilus influenzae (Hi) is the causative agent of several human diseases such as sepsis, meningitis, celulitis, and osteoarthritis. We investigated the isolation of Hi serotypes from sterile sites in sick children. One hundred and seventy nine strains from 146 patients were studied, period 1996-2002, at the Microbiology Laboratory, Hospital de Niños Superiora Sor María Ludovica, Argentina. The serotype distribution was:1 a, 112 b,1 c,1 d, 4 e, 3 f y 24 no typable. Since the beginning of universal Hi b vaccination in 1998, we have observed the fast decrease of serotype b and a relative increase of other serotypes.

Serotypes and antimicrobial susceptibility in clinical isolates of Haemophilus influenzae from Korean children in prevaccination era

Fifty-five strains of Haemophilus influenzae recovered at a children's hospital in Korea from 1992 through 1997, were analyzed for serotype and antibiotic resistance. Antimicrobial susceptibility was tested by broth dilution method. Among the 55 strains, 26 were from normally sterile body fluids, of which 17 were from the immunocompetent children. Spectrum in the immunocompetent included meningitis (47%), bacteremic pneumonia (18%), and bacteremia without focus (35%). Three (12%) of 26 invasive infections were caused by non-type b: one type d and two type f. Nine of 29 non-sterile body fluid isolates belonged to one of encapsulted serotypes: four a, two c, one of each of b, d and e. Thirty two (58%) strains were resistant to ampicillin, and all of which produced beta-lactamase. All of the strains were highly susceptible to amoxicillin/clavulanate, cefixime, cefuroxime, azithromycin and ciprofloxacin, while 1 (2%), 7 (13%), 4 (7%) and 4 (7%) strains were intermediate to cefprozil, cefaclor, loracarbef, and clarithromycin, respectively. The serotype distribution of H. influenzae in Korean children is similar to those in developed countries before the introduction of Hib conjugate vaccine, and ampicillin resistance rate is among the highest published to date.

Resistência à ampicilina e ao cloranfenicol entre isolados de Haemophilus spp. de um hospital pediátrico em Porto Algre / Resistance to ampicillin and chloramphenicol among isolates of haemophilus spp. in a pediatric hospital of Porto Alegre, Brazil

Resistência de Haemophilus spp. aos antimicrobianos é hoje um fenômeno mundial. A suscetibilidade de Haemophilus spp. de 102 isolados clínicos de crianças entre zero e 12 anos de idade foi avaliada frente à ampicilina e ao cloranfenicol. Testes de difusäo em agár com meio Haemophilus Test Medium foram empregados em todos os isolados, e em 84 deles foi também realizada pesquisa de Beta-lactamase pelo método da cefalosporina cromogênica. Resistência intermediária à ampicilina foi encontrada em 4,9 por cento (5/102) dos isolados. Entre isolados de fluidos normalmente estéreis, a resistência foi significativamente superior para ambos os antimicrobianos. Resultados obtidos apontam para a necessidade de realizaçäo sistemática de testes de suscetibilidade à ampicilina e ao cloranfenicol para isolados de Haemophilus spp

Febre purpúrica brasileira, virulência em modelo animal do Haemophilus aegyptius (H. influenzae biogrupo aegyptius) / Brazilian purpuric fever, virulence in an animal model of Haemophilus aegyptius (H. influenzae biogroup aegyptius). Grupo de Estudo da Febre Purpúrica Brasileira

Brazilian purpuric fever (BPF) is caused by invasive strains of Haemophilus aegyptius (H. influenzae biogroup aegyptius, Hae). These strains were differentiated from Hae strains associated only with conjunctivitis (non-invasive Hae strains) through specific molecular markers. Complement-depleted infant rat model was used to study the invasive and non-invasive Hae strains to compare their virulence potential. Inoculating 10(5) bacteria in the rats, the invasive strains caused 80 to 100 bacteremia and the intensity of bacteremia was 10(2.5 +/- 0.49) to > 10(4.69) cfu/ml of blood. Using the same infectious dose, the non-invasive strains did not cause frequent bacteremia (0 to 50) and the intensity was 0 to 10(3.69 +/- 0.53) cfu/ml of blood. The infectious doses able to cause 50 of bacteremia in the rats (BD 50) varied from < 10(3) to 10(4.2) bacteria for the invasive strains, whereas the BD 50 were 10(6.2) to > 10(7.3) bacteria for non-invasive strains. Passive immunization using antisera to invasive strains protected rats against bacteremia caused by homologous strains, but not by heterologous strain. By comparing the bacteremia caused by Hae and bacteremia caused by H. influenzae b (Eagan strain, Hib), it was demonstrated that Hib had higher virulence potential. This animal model was useful to clarify the virulence potential of invasive Hae strains.

Multiple typing of haemophilus influenzae isolates from the nasopharynx of Egyptian children inhabiting a rural area

One hundred and fifty strains of Haemophilus influenzae isolated from the nasopharynx of Egyptian children aged 1 month to 5 years inhabiting a rural area were subjected to biotyping, serotyping and antibiogram typing. The most prevalent biotypes encountered were biotype [I] [36%] and biotype [II] [31.3%]. Seventy percent of the isolates were non-typable. The typable strains [30%] belonged to the following serotypes: serotype [a] [12.7%], serotype [b] [12.7%], serotype [c] [0.6%], serotype [d] [1.4%], serotype [e] [2%] and serotype [f] [0.6%]. Serotype [b] was associated mainly with biotype [I]. Resistance was seen to be established for most antibiotics: ampicillin [4%], sulphonamide [4.7%], tetracycline [6%] and cephalexin [8%]. All isolates were sensitive to ofloxacin [100%] and cefotazime [100%]. Sensitivity to ceftriaxone was 99.3% and to trimethoprim-sulphamethoxazole was 98.7%

Gardnerella vaginalis: isolation and identification.

A total of 26 isolates of Gardnerella vaginalis were obtained from 248 patients attending the out patient department of Obstetrics and Gynaecology at A.I.I.M.S hospital, over a period of one year. The vaginal discharge of these patients was cultured on five different media in order to evaluate the best medium for the growth of G. vaginalis. Media containing human blood were found to be the most suitable, Human-Blood-Bilayer medium with Tween-80 being the best for the growth of the organism. A total of 12 biochemical tests were performed for the identification of each isolate. A short and rapid scheme for identification of the organism in a routine laboratory has been evolved.