Prevalence and characterization of pertactin deficient Bordetella pertussis strains in Brazil, a whole-cell vaccine country.

Many countries have reported antigenic divergence among circulating Bordetella pertussis strains, mainly in those countries which introduced the acellular pertussis (aP) vaccine. This phenomenon can be seen, for example, with the recent rise of pertactin (Prn)-deficient B. pertussis strains, one of the antigens included in aP vaccine formulas. The whole cell pertussis (wP) vaccine has been used in Brazil since 1977 for the primary pertussis, diphtheria and tetanus immunization series. In 2014, the aP vaccine was recommended for women during pregnancy to protect infants in the first months of life. Our objective was to determine the prevalence of Prn-deficiency in 511 isolates of B. pertussis collected in Brazil during 2010-2016. All isolates were characterized, through PFGE and serotyping, and screened for the loss of Prn by ELISA. Prn-deficiency was confirmed by immunoblotting, and identification of the possible genetic markers was performed with PCR and Sanger sequencing. Results indicate that 110 PFGE profiles are currently circulating, with five profiles representing the majority, and the predominant serotype 3, has been gradually replaced by serotype 2 and serotype 2,3. ELISA screening and immunoblotting identified three Prn-deficient isolates. Genotypic characterization by PCR and sequencing indicated that one isolate had a promoter mutation in prn, while the other two did not have an obvious genetic explanation for their deficiency. While the lack of Prn was identified in a few isolates, this study did not detect a relevant occurrence of Prn-deficiency, until 2016, confirming previous observations that Prn-deficiency is likely aP vaccine-driven.

Induction of apoptosis in Vero cells by Aeromonas veronii biovar sobria vacuolating cytotoxic factor.

Recently, a cytotoxin named vacuolating cytotoxic factor (VCF) in Aeromonas sobria and Aeromonas veronii biovar sobria was described. We have now purified this factor using ion metallic affinity chromatography. The VCF is a nonhemolytic enterotoxin that acts as a serine protease. The toxin can be partially neutralized by serum antiaerolysin and it induced not only cytoplasmatic vacuole formation, but also mitochondrial disorders that must be signaling the apoptotic pathways, leading to Vero (African green monkey kidney) cell death. These results suggest that the VCF is a virulence factor of these bacteria, participating in the processes of human disease provoked by preformed toxins in food and infection.

Plesiomonas shigelloides exports a lethal cytotoxic-enterotoxin (LCE) by membrane vesicles.

Plesiomonas shigelloides isolated from water in Brazil was previously described as a hemorrhagic heat-labile cytotoxic-enterotoxin producer. We purified this toxin from culture supernatants using ion metallic affinity chromatography (IMAC) followed by molecular exclusion chromatography. The pure toxin presented molecular mass of 50kDa and isoelectric point (pI) around 6.9 by 2D electrophoresis. When injected intravenously, the purified cytotoxic-enterotoxin induced also severe spasms followed by sudden death of mice. Hence, we entitled it as lethal cytotoxic-enterotoxin (LCE). The presence of membrane vesicles (MVs) on cell surfaces of P. shigelloides was observed by scan electron microscopy (SEM). From these MVs the LCE toxin was extracted and confirmed by biological and serological assays. These data suggest that P. shigelloides also exports this cytotoxic-enterotoxin by membrane vesicles, a different mechanism of delivering extra cellular virulence factors, so far not described in this bacterium.

DIARRHEA OUTBREAK IN PERNAMBUCO, BRAZIL, ASSOCIATED WITH A HEAT-STABLE CYTOTOXIC ENTEROTOXIN PRODUCED BY Aeromonas caviae.

In the present study enterotoxic and cytotoxic activities of twenty Aeromonas caviae strains were examined. They originated from fecal specimens of patients with acute diarrhea during an outbreak in Brazil in 2004. Culture supernatants of fourteen strains (70%) caused fluid accumulation in rabbit ileal intestinal loops and in suckling mice assays, and also showed a cytotoxic activity in Vero and Caco-2 cells. The enterotoxic and cytotoxic factors were heat-stable after culture supernatants treatment at 100 ºC. The results revealed that A. caviae strains produce a putative diarrheagenic virulence factor, a heat-stable cytotoxic enterotoxin that could be linked to the diarrhea outbreak that took place in Brazil.

Incidence of toxic Aeromonas isolated from food and human infection.

One hundred and ninety four Aeromonas isolates (99 from food and 95 from clinical sources) were analyzed as to the species involved and the toxins produced. Of the clinical isolates of Aeromonas, 29.4% were enterotoxigenic, 43.1% were hemolytic and 89% were cytotoxigenic. Among the food isolates, 18.2% were enterotoxigenic, 17.1% were hemolytic and 72.7% were cytotoxigenic. Aeromonas sobria and Aeromonas veronii produced more enterotoxin and cytotoxin than the other isolates, whereas A. veronii and Aeromonas salmonicida produced cell-free hemolysin. Most of the isolates produced cytotoxins (81%) active on Vero (green monkey kidney) and Chinese hamster ovary cells, but only the culture supernatant of A. sobria produced vacuolation in these cell lines.

Serodiagnosis as adjunct assay for pertussis infection in São Paulo, Brazil.

Pertussis remains an important public health problem in many countries despite extensive immunization. Cultures and real-time PCR (RT-PCR) assays are the recommended pertussis diagnostic tests, but they lack sensitivity at the later stage of the disease. This study introduces the IgG anti-pertussis toxin enzyme-linked immunosorbent assay (PT ELISA) in our routine diagnosis to improve disease burden estimation. Serum samples and nasopharyngeal swabs (n = 503) were collected at the same time from patients presenting with cough illness suspected of being pertussis and tested by the PT ELISA and culture and/or RT-PCR, respectively. Patients were separated into three age groups: group 1, <1 year (n = 260; mean age, 3 months), group 2, 1 to 6 years (n = 81; mean age, 3 years), and group 3, ≥7 years (n = 162; mean age, 26 years). The times (means) from cough onset to specimen collection were 16, 24, and 26 days, respectively. In group 1, 83 (82.2%) of 101 positive cases were positive for pertussis by culture/RT-PCR, while 40 (39.6%) tested positive by PT ELISA. In group 2, 6 (19.4%) of 31 positive cases were culture/RT-PCR positive, and 29 (93.6%) were seropositive. In group 3, 13 (13.8%) of 94 positive cases were positive by culture/RT-PCR and 91 (96.8%) were positive by serology. Culture/RT-PCR detected more cases of pertussis in infants (P < 0.0001), whereas the PT ELISA detected more cases in adolescents and adults (P < 0.0001). The timing between cough onset and specimen collection or recent vaccination may have partially affected our results. Serology is a suitable, cost-effective, and complementary pertussis diagnostic tool, especially among older children, adolescents, and adults during the later disease phase.

Identificação laboratorial da coqueluche na região do oeste do Estado de São Paulo / Laboratory identification of pertussis in the western region of São Paulo State, Brazil

O objetivo deste estudo foi de confirmar laboratorialmente os casos suspeitos de coqueluche na região oeste do Estado de São Paulo, ocorridos entre 2010 a 2015. A cultura foi realizada no Centro de Laboratório Regional - Instituto Adolfo Lutz de Presidente Prudente e a PCR em tempo real (qPCR) foi realizada no Centro de Referência Nacional para Pertussis – Instituto Adolfo Lutz em São Paulo, SP. Foram recebidas 189 amostras, sendo 29 (15,3%) confirmadas segundo os critérios laboratoriais (cultura e/ou qPCR). A faixa etária mais acometida foi em crianças menores de seis meses de idade (82,8%), não vacinados ou com o esquema de vacinação incompleto. Provavelmente, estes resultados representam apenas uma fração do número real de casos de coqueluche que ocorrem no Brasil. O contínuo monitoramento da doença e informações da prevalência por faixa etária são importantes ferramentas para melhorar as estratégias de imunização como forma de controlar esta doença reemergente.

The aim of this study was to confirm the suspected cases of pertussis in the Western region of the Sao Paulo State from 2010 to 2015. The samples were cultured in the Instituto Adolfo Lutz - Regional Laboratory of Presidente Prudente-SP, and the qPCR was performed at the National Reference Laboratory for Pertussis – Central Instituto Adolfo Lutz, São Paulo-SP. In this period, 189 samples were received, being 29 (15.3%) confirmed by the laboratory criteria (culture and/or qPCR). The most affected group was the children less than six months old (82.8%), not vaccinated or with the incomplete vaccination. Most likely, these results only represent a fraction of the actual number of pertussis cases occurring in Brazil. The continuous disease monitoring and the prevalence data by age group are fundamental to improve the immunization strategies as a way to control this important re-emerging disease.

Identificação laboratorial da coqueluche na região do oeste do Estado de São Paulo / Laboratory identification of pertussis in the western region of São Paulo, Brasil

O objetivo deste estudo foi de confirmar laboratorialmente os casos suspeitos de coqueluchena região oeste do Estado de São Paulo, ocorridos entre 2010 a 2015. A cultura foi realizadano Centro de Laboratório Regional - Instituto Adolfo Lutz de Presidente Prudente e a PCR emtempo real (qPCR) foi realizada no Centro de Referência Nacional para Pertussis – Instituto AdolfoLutz em São Paulo, SP. Foram recebidas 189 amostras, sendo 29 (15,3%) confirmadas segundoos critérios laboratoriais (cultura e/ou qPCR). A faixa etária mais acometida foi em criançasmenores de seis meses de idade (82,8%), não vacinados ou com o esquema de vacinação incompleto.Provavelmente, estes resultados representam apenas uma fração do número real de casos decoqueluche que ocorrem no Brasil. O contínuo monitoramento da doença e informações daprevalência por faixa etária são importantes ferramentas para melhorar as estratégias de imunizaçãocomo forma de controlar esta doença reemergente.

The aim of this study was to confirm the suspected cases of pertussis in the Western region ofthe Sao Paulo State from 2010 to 2015. The samples were cultured in the Instituto Adolfo Lutz -Regional Laboratory of Presidente Prudente-SP, and the qPCR was performed at the NationalReference Laboratory for Pertussis – Central Instituto Adolfo Lutz, São Paulo-SP. In this period,189 samples were received, being 29 (15.3%) confirmed by the laboratory criteria (culture and/orqPCR). The most affected group was the children less than six months old (82.8%), not vaccinatedor with the incomplete vaccination. Most likely, these results only represent a fraction of theactual number of pertussis cases occurring in Brazil. The continuous disease monitoring and theprevalence data by age group are fundamental to improve the immunization strategies as a way tocontrol this important re-emerging disease.

Pertussis characterization in the central-west region of São Paulo state, Brazil / Caracterização da coqueluche na região centro-oeste do Estado de São Paulo, Brasil

Pertussis is a highly contagious respiratory disease caused by Bordetella pertussis. This study aimed at characterizing the B. pertussis laboratory positivity and the isolated strains inmunicipalities of the Central-West Region of São Paulo State, Brazil from 2010 to 2014. A total of 597 nasopharyngeal swabs samples were collected from suspected patients and contacts, andanalyzed by in vitro culture and Real-Time PCR (qPCR). Culture-positive B. pertussis strains were characterized by serotyping and pulsed-field gel electrophoresis. Considering culture and/or qPCR, the positivity rate was of 19.6%. Out of 117 samples with B. pertussis, 23 were detected by both methods, 89 by qPCR only and five by culture only. Strains presenting FIM3 (40%), FIM2,3 (32%) and FIM2 (28%) serotypes were found. Five pulsotypes were detected by PFGE,48% of which identified as BP.Xba.0039, being the predominant type in this study. Among the positive strains, 50% were isolated from <2 months old-children and 17% were isolated from three to six months old patients. Non-vaccinated children or with incomplete vaccination schedule were at the major risk of complications and death, highlighting the importance of a continuous monitoring of this infection for the future control strategies.

A coqueluche é uma doença respiratória altamente contagiosa causada por Bordetella pertussis. Este estudo caracterizou a positividade de B. pertussis e as cepas isoladas em municípios da Região Centro-Oeste do Estado de São Paulo de 2010 a 2014. Foram coletados 597 esfregaços nasofaríngeos de pacientes e contatos suspeitos de coqueluche, e analisados por cultura e Real-Time PCR (qPCR). Os isolados de B. pertussis obtidos de cultura foram caracterizados por sorotipagem e eletroforese em gel de campo pulsado. Considerando-se a cultura e/ou qPCR, verificou-se taxa de positividade de 19,6%. Das 117 amostras positivas para B. pertussis, 23 foram detectadas por ambos os métodos, 89 apenas por qPCR e cinco apenas na cultura. Foram detectadas cepas de sorotipos FIM3 (40%), FIM2,3 (32%) e FIM2 (28%). Cinco pulsotipos foram detectados pela PFGE, e 48% identificados como BP.Xba.0039, o tipo predominante neste estudo. Entre as cepas positivas, 50% foram isoladas de crianças menores de dois meses e 17% isoladas da faixa etária de três a seis meses. Crianças não vacinadas ou com esquema de vacinação incompleta têm maior risco de complicações e óbito, o que ressalta a importância do monitoramento contínuo desta infecção para futuras estratégias de controle.

Pertussis characterization in the central-west region of São Paulo state, Brazil / Caracterização da coqueluche na região centro-oeste do Estado de São Paulo, Brasil

Pertussis is a highly contagious respiratory disease caused by Bordetella pertussis. This study aimed at characterizing the B. pertussis laboratory positivity and the isolated strains in municipalities of the Central-West Region of São Paulo State, Brazil from 2010 to 2014. A total of 597 nasopharyngeal swabs samples were collected from suspected patients and contacts, and analyzed by in vitro culture and Real-Time PCR (qPCR). Culture-positive B. pertussis strains were characterized by serotyping and pulsed-field gel electrophoresis. Considering culture and/or qPCR, the positivity rate was of 19.6%. Out of 117 samples with B. pertussis, 23 were detected by both methods, 89 by qPCR only and five by culture only. Strains presenting FIM3 (40%), FIM2,3 (32%) and FIM2 (28%) serotypes were found. Five pulsotypes were detected by PFGE, 48% of which identified as BP.Xba.0039, being the predominant type in this study. Among the positive strains, 50% were isolated from <2 months old-children and 17% were isolated from three to six months old patients. Non-vaccinated children or with incomplete vaccination schedule were at the major risk of complications and death, highlighting the importance of a continuous monitoring of this infection for the future control strategies.

A coqueluche é uma doença respiratória altamente contagiosa causada por Bordetella pertussis. Este estudo caracterizou a positividade de B. pertussis e as cepas isoladas em municípios da Região Centro-Oeste do Estado de São Paulo de 2010 a 2014. Foram coletados 597 esfregaços nasofaríngeos de pacientes e contatos suspeitos de coqueluche, e analisados por cultura e Real-TimePCR (qPCR). Os isolados de B. pertussis obtidos de cultura foram caracterizados por sorotipagem e eletroforese em gel de campo pulsado. Considerando-se a cultura e/ou qPCR, verificou-se taxa de positividade de 19,6%. Das 117 amostras positivas para B. pertussis, 23 foram detectadas por ambos os métodos, 89 apenas por qPCR e cinco apenas na cultura. Foram detectadas cepas de sorotipos FIM3 (40%), FIM2,3 (32%) e FIM2 (28%). Cinco pulsotipos foram detectados pela PFGE, e 48% identificados como BP.Xba.0039, o tipo predominante neste estudo. Entre as cepas positivas, 50% foram isoladas de crianças menores de dois meses e 17% isoladas da faixa etária de três a seis meses. Crianças não vacinadas ou com esquema de vacinação incompleta têm maior risco de complicações e óbito, o que ressalta a importância do monitoramento contínuo desta infecção para futuras estratégias de controle.

Plesiomonas shigelloides exports a lethal cytotoxic-enterotoxin (LCE) by membrane vesicles

ABSTRACT Plesiomonas shigelloides isolated from water in Brazil was previously described as a hemorrhagic heat-labile cytotoxic-enterotoxin producer. We purified this toxin from culture supernatants using ion metallic affinity chromatography (IMAC) followed by molecular exclusion chromatography. The pure toxin presented molecular mass of 50 kDa and isoelectric point (pI) around 6.9 by 2D electrophoresis. When injected intravenously, the purified cytotoxic-enterotoxin induced also severe spasms followed by sudden death of mice. Hence, we entitled it as lethal cytotoxic-enterotoxin (LCE). The presence of membrane vesicles (MVs) on cell surfaces of P. shigelloides was observed by scan electron microscopy (SEM). From these MVs the LCE toxin was extracted and confirmed by biological and serological assays. These data suggest that P. shigelloides also exports this cytotoxic-enterotoxin by membrane vesicles, a different mechanism of delivering extra cellular virulence factors, so far not described in this bacterium.

Diarrhea outbreak in Pernambuco, Brazil, associated with a heat-stable cytotoxic enterotoxin produced by Aeromonas caviae / O surto de diarreia em Pernambuco, Brasil é associado com uma enterotoxina citotóxica termo-estável produzida por Aeromonas caviae

SUMMARYIn the present study enterotoxic and cytotoxic activities of twenty Aeromonas caviaestrains were examined. They originated from fecal specimens of patients with acute diarrhea during an outbreak in Brazil in 2004. Culture supernatants of fourteen strains (70%) caused fluid accumulation in rabbit ileal intestinal loops and in suckling mice assays, and also showed a cytotoxic activity in Vero and Caco-2 cells. The enterotoxic and cytotoxic factors were heat-stable after culture supernatants treatment at 100 ºC. The results revealed that A. caviaestrains produce a putative diarrheagenic virulence factor, a heat-stable cytotoxic enterotoxin that could be linked to the diarrhea outbreak that took place in Brazil.

RESUMOEm 2004 ocorreu um surto de diarreia aguda no Estado de Pernambuco, Brasil. Setenta por cento (14 dos 20) dos sobrenadantes de cultura de Aeromonas caviae,isoladas neste episódio induziram acúmulo de líquido em testes de alça ligada de intestino de coelhos, assim como em teste em camundongos recém-nascidos. Os mesmos sobrenadantes mostraram também atividade citotóxica em células de Vero e Caco-2, mas não em células HeLa e HEp2. As atividades enterotóxicas e citotóxicas mantiveram-se mesmo após o aquecimento a 100 ºC dos sobrenadantes de cultura. Este trabalho revela a expressão de um provável fator diarreiogênico: uma enterotoxina-citotóxica termo-estável, produzida por A. caviaeque pode ser associada ao surto de diarreia ocorrido no Brasil. Atualmente estamos purificando esta enterotoxina termo-estável, com o objetivo de elucidar seu papel como fator de virulência na diarreia causada por A. caviae.

Exacerbation of Leishmania (Viannia) shawi infection in BALB/c mice after immunization with soluble antigen from amastigote forms.

The present study aimed to evaluate the effects of immunization with soluble amastigote (AmaAg) and promastigote (ProAg) antigens from Leishmania (Viannia) shawi on the course of infection in BALB/c mice. After immunization with AmaAg, the challenged group showed greater lesion size and parasite load in the skin and lymph nodes, associated with diminished interleukin (IL)-2, IL-4, IL-10, interferon (IFN)-γ and nitrate levels in the supernatant of lymph node cell cultures, together with increases in transforming growth factor (TGF)-ß concentrations and humoral immune response. In contrast, immunization with ProAg led to smaller lesion size with reduced numbers of viable parasites in the skin. Protection was associated with increases in IL-12, IFN-γ, TGF-ß and nitrates and decreases in IL-4 and IL-10 levels. Concerning humoral immune response, a significant reduction in anti-leishmania immunoglobulin G was verified in the ProAg-challenged group. Analysis of these results suggests that AmaAg induced a suppressive cellular immune response in mice, favouring the spread of infection, whereas ProAg induced partial protection associated with increased cellular immune response.