Bacillus sphaericus mosquito pathogens in the aquatic environment

The fate of Bacillus sphaericus spores in the aquatic environment was investigated by suspending spores in dialysis bags in fresh and seawater. Spore viability was lost more rapidly in seawater. Neither B. sphaericus nor B. thuringiensis israelensis (B.t.i.) spores mixed with pond sediment appeared to attach to the sediment. However, rapid decrease in B.t.i. toxicity suggested attachment of parasporal bodies to sediment. B. sphaericus toxin settled more slowly and less completely. B. sphaericus spores fed to larvae of four aquatic invertebrates were mostly eliminated from the animal gut in less than one week. An exception was the cranefly (Tipula abdominalis) where spores persisted in the posterior gut for up to five weeks.

Nôvo meio para isolamento de enterobacteriáceas e diferenciação simultânea das colônias de Proteus e Providência

Um nôvo meio é proposto para o isolamento de enterobacteriáceas. Baseia-se na propriedade de desanimar a fenil-alanina que possuem tôdas as bactérias dos grupos Proteus e Providencia. As colônias dêstes microrganismos apresentam no meio descrito coloração marrom característica. As colônias das outras enterobacteriáceas, fermentadoras rápidas ou lentas e não fermentadoras da lactose, apresentam aspecto diferente.

Occurrence of Proteus mirabilis associated with two species of venezuelan oysters

The fecal contamination of raw seafood by indicators and opportunistic pathogenic microorganisms represents a public health concern. The objective of this study was to investigate the presence of enteric bacteria colonizing oysters collected from a Venezuelan touristic area. Oyster samples were collected at the northwestern coast of Venezuela and local salinity, pH, temperature, and dissolved oxygen of seawater were recorded. Total and fecal coliforms were measured for the assessment of the microbiological quality of water and oysters, using the Multiple Tube Fermentation technique. Analyses were made using cultures and 16S rRNA gene sequencing. Diverse enrichment and selective culture methods were used to isolate enteric bacteria. We obtained pure cultures of Gram-negative straight rods with fimbriae from Isognomon alatus and Crassostrea rhizophorae. Our results show that P. mirabilis was predominant under our culture conditions. We confirmed the identity of the cultures by biochemical tests, 16S rRNA gene sequencing, and data analysis. Other enterobacteria such as Escherichia coli, Morganella morganii and Klebsiella pneumoniae were also isolated from seawater and oysters. The presence of pathogenic bacteria in oysters could have serious epidemiological implications and a potential human health risk associated with consumption of raw seafood.

Detection of bla KPC-2 in Proteus mirabilis in Brazil

INTRODUCTION : Infections caused by Klebsiella pneumoniae carbapenemase (KPC)-producing isolates pose a major worldwide public health problem today. METHODS : A carbapenem-resistant Proteus mirabilis clinical isolate was investigated for plasmid profiles and the occurrence of β-lactamase genes. RESULTS : The isolate exhibited resistance to ertapenem and imipenem and was susceptible to meropenem, polymyxin, and tigecycline. Five plasmids were identified in this isolate. DNA sequencing analysis revealed the presence of bla KPC-2 and bla TEM-1 genes. An additional PCR using plasmid DNA confirmed that bla KPC-2 was present in one of these plasmids. Conclusions: We report the detection of bla KPC-2 in P. mirabilis in Brazil for the first time. This finding highlights the continuous transfer of bla KPC between bacterial genera, which presents a serious challenge to the prevention of infection by multidrug-resistant bacteria.

Contribution to the normal fecal flora of the hamster: Proteus mirabilis in normal feces of hamster

Proteus mirabilis must be considered a normal inhabitant of the intestine of hamsters. It is also found in the vaginal secretion of females of this animal, when in oestrus.

Microscopia eletrônica de granulações em Proteus vulgaris tratado como Cloreto de Trifeniltetrazólio

Zonas citoplasmáticas de atividade redutora de TTC foram evidenciadas em células de Proteus vulgaris examinadas ao microscópio eletrõnico. As experiências foram realizadas em vários intervalos de tempo, sendo a reação, em alguns casos, estabilizada por meio de formol. Verificou-se que as granulações de formazana podiam ser removidas no interior do corpo bacteriano por meio de tratamento com acetona. O bombardeamento pelos eléctrons, quando os germes não tinham sido fixados com formol, determinou a saída das granulações do interior dos bacilos, deixando vestígios de sua presença (rompimento das membranas celulares nos pontos onde estavam localizados). A fixação com formol evitava a saída dos grânulos. O acúmulo dos cristais de formazana, internamente, nos pólos ou ao longo do corpo bacteriano, provoca sérias alterações morfológicas.

Ciclo "L" em Proteus vulgaris: I - massas nucleares em esferoplastos induzidos pela penicilina

Esferoplastos foram obtidos em Proteus vulgaris, cultivado em meio sintético simples, tendo como agente indutor a penicilina, em diferentes concentrações. Estabelecida a dosagem ótima, de sensibilidade da bactéria ao antibiótico, para obtenção de "grandes corpos" do Ciclo "L", definidos, morfologicamente, como esferoplastos, foi feita a coloração de massas nucleares, em diversas fases do crescimento bacteriano. A colheita do material foi feita por impessão em lamínula, usando-se ácido ósmico como fixador, seguindo-se hidrólise clorídrica, com aquecimento, e coloração pela fucsina. Dos resultados conseguidos ficou evidenciado: 1º - a posssibilidade de obtenção de "grandes corpos" em Proteus vulgaris em um meio sintético simples, a base de sais minerais e glicose; 2º - que houve uma concentração ótima de penicilina para surgir o efeito indutor de esferoplasto, na fase logarítmica de crescimento; 3º - a facilidade de coloração de massas nucleares nos esferoplastos em vários períodos de crescimento; 4º - a reversão ao tipo morfológico normal, depois de 24 horas de crescimento no meio com o antibiótico; 5º - modificação no crescimento do Proteus vulgaris em superfície de agar, com dose mínima de penicilina formando colônias localizadas.

Mini-Mu insertions in the tetracycline resistance determinant from Proteus mirabilis

The inducible tetracycline resistance determinant isolated from Proteus mirabilis cloned into the plasmid pACYC177 was mutagenized by insertion of a mini-Mu-lac phage in order to define the regions in the cloned sequences encoding the structural and regulatory proteins. Three different types of mutants were obtained: one lost the resistance phenotype and became Lac+; another expressed the resistance at lower levels and constitutively; the third was still dependent on induction but showed a lower minimal inhibitory concentration. The mutant phenotypes and the locations of the insertions indicate that the determinant is composed of a repressor gene and a structural gene which are not transcribed divergently as are other known tetracycline determinants isolated from Gram-negative bacteria

Development of an operational substrate for ZapA, a metalloprotease secreted by the bacterium Proteus mirabilis

The protease ZapA, secreted by Proteus mirabilis, has been considered to be a virulence factor of this opportunistic bacterium. The control of its expression requires the use of an appropriate methodology, which until now has not been developed. The present study focused on the replacement of azocasein with fluorogenic substrates, and on the definition of enzyme specificity. Eight fluorogenic substrates were tested, and the peptide Abz-Ala-Phe-Arg-Ser-Ala-Ala-Gln-EDDnp was found to be the most convenient for use as an operational substrate for ZapA. A single peptide bond (Arg-Ser) was cleaved with a Km of 4.6 µM, a k cat of 1.73 s-1, and a catalytic efficiency of 376 (mM s)-1. Another good substrate for ZapA was peptide 6 (Abz-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-Gln-EDDnp) which was cleaved at a single bond (Phe-Ser) with a Km of 13.6 µM, a k cat of 3.96 s-1 and a catalytic efficiency of 291 (mM s)-1. The properties of the amino acids flanking the scissile bonds were also evaluated, and no clear requirement for the amino acid residue at P1 was found, although the enzyme seems to have a preference for a hydrophobic residue at P2.

ZapA, a possible virulence factor from Proteus mirabilis exhibits broad protease substrate specificity

The opportunistic bacterium Proteus mirabilis secretes a metalloprotease, ZapA, considered to be one of its virulence factors due to its IgA-degrading activity. However, the substrate specificity of this enzyme has not yet been fully characterized. In the present study we used fluorescent peptides derived from bioactive peptides and the oxidized ß-chain of insulin to determine the enzyme specificity. The bradykinin- and dynorphin-derived peptides were cleaved at the single bonds Phe-Ser and Phe-Leu, with catalytic efficiencies of 291 and 13 mM/s, respectively. Besides confirming already published cleavage sites, a novel cleavage site was determined for the ß-chain of insulin (Val-Asn). Both the natural and the recombinant enzyme displayed the same broad specificity, demonstrated by the presence of hydrophobic, hydrophilic, charged and uncharged amino acid residues at the scissile bonds. Native IgA, however, was resistant to hydrolysis by ZapA.

Achado de bactérias selecionadas em crianças de Trinidad com doença amigdaliana crônica

Faringoamigdalite na população pediátrica é largamente tratada com antibióticos. OBJETIVO: Estudar a microflora presente na superfície e no núcleo de amígdalas após adenoamigdalectomia eletiva em crianças. MÉTODO: Amígdalas de 102 crianças de Trinidad foram prospectivamente estudadas por meio de culturas e identificações bacteriológicas feitas a partir de amostras das superfícies e núcleos de suas amígdalas entre 2005-2006. RESULTADOS: A partir de 360 amígdalas, foram isolados Streptococcus spp. (51,3%), Staphylococcus spp. (42,3%) e Gram-Negativos (6,4%). A identificação de estafilococos e estreptococos tanto na superfície quanto no núcleo foi semelhante (p>0,05). Encontramos mais (p<0,001) Streptococcus spp. nas superfícies (82,2%) do que nos núcleos (63,3%); a prevalência de estreptococos alfa-hemolíticos foi maior (p<0,001) do que aquela de estreptococos beta-hemolíticos nas superfícies (74,4% vs. 18,6%) do que nos núcleos (58,9% vs. 13,7%). Não houve concordância entre superfícies e núcleos com relação a estreptococos (p<0,0004) e estreptococos alfa-hemolíticos (p<0,007). Estreptococos beta-hemolíticos foram mais identificados (p<0,05) em crianças dentre 6-16 anos do que naquelas entre 1-5 anos de idade (31% e 23,8% vs 12,5% e 8%). A prevalência de S. pyogenes na superfície e no núcleo foi de (84,6% vs 70%) e (50,0% vs 25,0%) em crianças de maior faixa etária e crianças mais novas, respectivamente. Klebsiella spp. (6,6%, 2,2%), Proteus (4,4%, 4,4%) e Pseudomonas (4,4 %, 1,1%) cresceram nas superfícies e núcleos, respectivamente. CONCLUSÃO: As superfícies amigdalianas tinham mais estreptococos e estreptococos hemolíticos do que seus núcleos. Crianças mais velhas tiveram mais estreptococos beta-hemolíticos, e são altamente colonizadoras de S. pyogenes. Sugerimos estudos que investiguem os mecanismos de aderência estreptocócica em crianças de Trinidad.

Atividade antibacteriana de óleos essenciais em cepas isoladas de infecção urinária

A análise da atividade antibacteriana de óleos essenciais de ervas medicinais (Ocimum gratissimum, L., Cybopogum citratus (DC) Stapf. e Salvia officinalis, L.) foi verificada frente a 100 cepas de bactérias isoladas de indivíduos da comunidade com diagnóstico de infecção urinária. Os microrganismos foram semeados em ágar Muller Hinton e os extratos aplicados com replicador de Steers e incubados a 37°C por 24 horas. Verificou-se que Salvia officinalis, L. apresentou ação inibitória superior às outras ervas, tendo eficácia de 100% quando testadas em espécies de Klebsiella e Enterobacter, 96% em Escherichia coli, 83% contra Proteus mirabilis e 75% contra Morganella morganii.

Rickettsiosis cutáneo ganglionar por Rickettsia conorii en el Uruguay

Se refieren 3 casos autóctonos de rickettsiosis cutáneo ganglionar trasmitidos por garrapatas de perros (Amblyomma maculatum, en uno de ellos) en el Uruguay. Dos de los 3 casos fueron seguramente provocados por Rickettsia conorii de acuerdo a los resultados de la reacción específica de inmunofluorescencia indirecta - IgM, anti R. conorii. Se incluye un tercer paciente no estudiado con tal técnica, por la similitud clínico-epidemiológica, la reactividad del suero frente al Proteus OX 19 y la rápida respuesta a la tetraciclina. La no descripción previa de la rickettsiosis por R. conorii en forma autóctona en el área de las Américas confiere especial interés a la comunicación, recomendándose la búsqueda de la afección en otros países de la región.

Extended-spectrum beta-lactamases among Enterobacteriaceae isolated in a public hospital in Brazil

Extended-spectrum β-lactamases (ESBL) in enterobacteria are recognized worldwide as a great hospital problem. In this study, 127 ESBL-producing Enterobacteriaceae isolated in one year from inpatients and outpatients at a public teaching hospital at São Paulo, Brazil, were submitted to analysis by PCR with specific primers for blaSHV, blaTEM and blaCTX-M genes. From the 127 isolates, 96 (75.6%) Klebsiella pneumoniae, 12 (9.3%) Escherichia coli, 8 (6.2%) Morganella morganii, 3 (2.3%) Proteus mirabilis, 2 (1.6%) Klebsiella oxytoca, 2 (1.6%) Providencia rettgeri, 2 (1.6%) Providencia stuartti, 1 (0.8%) Enterobacter aerogenes and 1 (0.8%) Enterobacter cloacae were identified as ESBL producers. BlaSHV, blaTEM and blaCTX-M were detected in 63%, 17.3% and 33.9% strains, respectively. Pulsed field gel eletrophoresis genotyping of K. pneumoniae revealed four main molecular patterns and 29 unrelated profiles. PCR results showed a high variety of ESBL groups among strains, in nine different species. The results suggest the spread of resistance genes among genetically different strains of ESBL-producing K. pneumoniae in some hospital wards, and also that some strongly related strains were identified in different hospital wards, suggesting clonal spread in the institutional environment.

ENTEROPATHOGENS DETECTED IN A DAYCARE CENTER, SOUTHEASTERN BRAZIL: BACTERIA, VIRUS, AND PARASITE RESEARCH

Introduction: The objective of this study was to determine the prevalence and etiological profile of enteropathogens in children from a daycare center. Methods: From October 2010 to February 2011 stool samples from 100 children enrolled in a government daycare center in the municipality of São José do Rio Preto, in the state of São Paulo, were collected and analyzed. Results: A total of 246 bacteria were isolated in 99% of the fecal samples; 129 were in the diarrheal group and 117 in the non-diarrheal group. Seventy-three strains of Escherichia coli were isolated, 19 of Enterobacter, one of Alcaligenes and one of Proteus. There were 14 cases of mixed colonization with Enterobacter and E. coli. Norovirus and Astrovirus were detected in children with clinical signs suggestive of diarrhea. These viruses were detected exclusively among children residing in urban areas. All fecal samples were negative for the presence of the rotavirus species A and C. The presence of Giardia lamblia, Entamoeba coli, Endolimax nana and hookworm was observed. A significant association was found between food consumption outside home and daycare center and the presence of intestinal parasites. Conclusions: For children of this daycare center, intestinal infection due to pathogens does not seem to have contributed to the occurrence of diarrhea or other intestinal symptoms. The observed differences may be due to the wide diversity of geographical, social and economic characteristics and the climate of Brazil, all of which have been reported as critical factors in the modulation of the frequency of different enteropathogens.