RESUMO
BACKGROUND: Serratia marcescens becomes an apparent nosocomial pathogen and causes a variety of infections. S. marcescens possess various virulence factors that are regulated by intercellular communication system quorum sensing (QS). Targeting bacterial virulence is a proposed strategy to overcome bacterial resistance. Sitagliptin anti-QS activity has been demonstrated previously and we aimed in this study to investigate the effects of antidiabetic drugs vildagliptin and metformin compared to sitagliptin on S. marcescens pathogenesis. METHODS: We assessed the effects of tested drugs in subinhibitory concentrations phenotypically on the virulence factors and genotypically on the virulence encoding genes' expressions. The protection of tested drugs on S. marcescens pathogenesis was performed in vivo. Molecular docking study has been conducted to evaluate the interference capabilities of tested drugs to the SmaR QS receptor. RESULTS: Vildagliptin reduced the expression of virulence encoding genes but did not show in vitro or in vivo anti-virulence activities. Metformin reduced the expression of virulence encoding genes and inhibited bacterial virulence in vitro but did not show in vivo protection. Sitagliptin significantly inhibited virulence factors in vitro, reduced the expression of virulence factors and protected mice from S. marcescens. Docking study revealed that sitagliptin is more active than metformin and fully binds to SmaR receptor, whereas vildagliptin had single interaction to SmaR. CONCLUSION: The downregulation of virulence genes was not enough to show anti-virulence activities. Hindering of QS receptors may play a crucial role in diminishing bacterial virulence.
Assuntos
Antibacterianos/farmacologia , Reposicionamento de Medicamentos , Hipoglicemiantes/farmacologia , Infecções por Serratia/tratamento farmacológico , Serratia marcescens/efeitos dos fármacos , Animais , Antibacterianos/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Hipoglicemiantes/química , Metformina/química , Metformina/farmacologia , Camundongos , Simulação de Acoplamento Molecular , Infecções por Serratia/microbiologia , Serratia marcescens/genética , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Vildagliptina/química , Vildagliptina/farmacologia , Virulência/efeitos dos fármacos , Fatores de Virulência/química , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Multidrug resistance prompts the search for new sources of antibiotics with new targets at bacteria cell. To investigate the antibacterial activity of Cinnamomum cassia L. essential oil (CCeo) alone and in combination with antibiotics against carbapenemase-producing Klebsiella pneumoniae and Serratia marcescens. The antimicrobial susceptibility of the strains was determined by Vitek® 2 and confirmed by MALDI-TOF/TOF. The antibacterial activity of CCeo and its synergism with antibiotics was determined using agar disk diffusion, broth microdilution, time-kill, and checkboard methods. The integrity of the bacterial cell membrane in S. marcescens was monitored by protein leakage assay. CCeo exhibited inhibitory effects with MIC = 281.25 µg.mL-1. The association between CCeo and polymyxin B showed a decrease in terms of viable cell counts on survival curves over time after a 4 hour-treatment with a FIC index value of 0.006. Protein leakage was observed with increasing concentrations for CCeo and CCeo + polymyxin B treatments. CCeo showed antibacterial activity against the studied strains. When associated with polymyxin B, a synergistic effect was able to inhibit bacterial growth rapidly and consistently, making it a potential candidate for the development of an alternative treatment and drug delivery system for carbapenemase-producing strains.
Assuntos
Infecções por Klebsiella/tratamento farmacológico , Óleos Voláteis/farmacologia , Polimixina B/farmacologia , Infecções por Serratia/tratamento farmacológico , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Cinnamomum aromaticum/química , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Sinergismo Farmacológico , Humanos , Infecções por Klebsiella/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Infecções por Serratia/genética , Infecções por Serratia/microbiologia , Serratia marcescens/efeitos dos fármacos , Serratia marcescens/patogenicidade , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , beta-Lactamases/genéticaRESUMO
In nature, microorganisms often exhibit competitive behavior for nutrients and limited space, allowing them to alter the virulence determinants of pathogens. The human pathogenic yeast Cryptococcus neoformans can be found organized in biofilms, a complex community composed of an extracellular matrix which confers protection against predation. The aim of this study was to evaluate and characterize antagonistic interactions between two cohabiting microorganisms: C. neoformans and the bacteria Serratia marcescens. The interaction of S. marcescens with C. neoformans expressed a negative effect on biofilm formation, polysaccharide capsule, production of urease, and melanization of the yeast. These findings evidence that competition in mixed communities can result in dominance by one species, with direct impact on the physiological modulation of virulence determinants. Such an approach is key for understating the response of communities to the presence of competitors and, ultimately, rationally designing communities to prevent and treat certain diseases.
Assuntos
Biofilmes , Cryptococcus neoformans , Interações Microbianas , Serratia marcescens , Cryptococcus neoformans/patogenicidade , Cryptococcus neoformans/fisiologia , Interações Microbianas/fisiologia , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Fatores de Virulência/metabolismoRESUMO
Background: Serratia marcescens is an enteric bacterium with increasing incidence in clinical settings, attributed mainly to the opportune expression of diverse virulence determinants plus a wide intrinsic and acquired antibiotic resistance. Methods: The aim of this study was to compare the virulence factor profiles of 185 Serratia marcescens isolates from different clinical origins. In vitro proteolytic and hemolytic activities, biofilm formation, and motility were assessed in each strain. Additionally, the pathogenicity of four hypervirulent strains was analyzed in vivo in Galleria mellonella. Results: We found that bacterial isolates from wound/abscess and respiratory tract specimens exhibited the highest protease activity along with a strong biofilm production, while uropathogenic isolates showed the highest hemolytic activity. Swarming and swimming motilities were similar among all the strains. However, respiratory tract isolates showed the most efficient motility. Two hyperhemolytic and two hyperproteolytic strains were detected; the latter were more efficient killing Galleria mellonella with a 50%-60% larval mortality 48 hours after challenge. Conclusion: A correlation was found between biofilm formation and proteolytic and hemolytic activities in biopsy specimens and bloodstream isolates, respectively. Overall, it becomes critical to evaluate and compare the clinical strains virulence diversity in order to understand the underlying mechanisms that allow the establishment and persistence of opportunistic bacterial infections in the host.
Assuntos
Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Serratia marcescens/patogenicidade , Biofilmes/crescimento & desenvolvimento , Infecção Hospitalar , Hemólise/fisiologia , Humanos , México/epidemiologia , Peptídeo Hidrolases/fisiologia , Serratia marcescens/isolamento & purificação , Virulência , Fatores de VirulênciaRESUMO
Serratia marcescens is an opportunistic pathogen with increasing incidence in clinical settings. This is mainly attributed to the timely expression of a wide diversity of virulence factors and intrinsic and acquired resistance to antibiotics, including ß-lactams, aminoglycosides, quinolones, and polypeptides. For these reasons, S. marcescens has been recently categorised by the World Health Organization as one priority to strengthen efforts directed to develop new antibacterial agents. Therefore, it becomes critical to understand the underlying mechanisms that allow Serratia to succeed within the host. S. marcescens ShlA pore-forming toxin mediates phenotypes that alter homeostatic and signal transduction pathways of host cells. It has been previously demonstrated that ShlA provokes cytotoxicity, haemolysis and autophagy and also directs Serratia egress and dissemination from invaded nonphagocytic cells. However, molecular details of ShlA mechanism of action are still not fully elucidated. In this work, we demonstrate that Ni2+ selectively and reversibly blocks ShlA action, turning wild-type S. marcescens into a shlA mutant strain phenocopy. Combined use of Ni2+ and calcium chelators allow to discern ShlA-triggered phenotypes that require intracellular calcium mobilisation and reveal ShlA function as a calcium channel, providing new insights into ShlA mode of action on target cells.
Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Canais de Cálcio/metabolismo , Proteínas Hemolisinas/antagonistas & inibidores , Níquel/farmacologia , Serratia marcescens/efeitos dos fármacos , Fatores de Virulência/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/metabolismo , Células CHO , Cálcio/metabolismo , Cricetulus , Eritrócitos/microbiologia , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/toxicidade , Hemólise/efeitos dos fármacos , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Humanos , Fenótipo , Serratia marcescens/metabolismo , Serratia marcescens/patogenicidadeRESUMO
Immune priming in invertebrates refers to an improved immune response (and therefore a better chance of survival) upon a second encounter with a specific pathogen. Although the existence of immune priming has been evaluated in invertebrate hosts, the ability of a particular entomopathogen species or strain to influence the occurrence of immune priming has not been thoroughly evaluated. The aim of the current study was to compare the occurrence of immune priming in Tenebrio molitor larvae after homologous challenges (a dual exposure to similar entomopathogens) with Serratia marcescens, Bacillus thuringiensis and Metarhizium anisopliae. Larvae presented more effective immune priming (measured as survival rates) when exposed to M. anisopliae or B. thuringiensis than when exposed to S. marcescens. We hypothesize that the toll pathway may help T. molitor survive these enemies and that the IMD pathway may be expressed to a lesser degree in this species, which may explain why they succumb to Gram-negative bacteria. This and other recent evidence suggest that the occurrence of immune priming in these organisms must not be ruled out until this phenomenon is tested with different entomopathogens.
Assuntos
Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata , Larva/imunologia , Tenebrio/imunologia , Animais , Bacillus thuringiensis/patogenicidade , Larva/microbiologia , Metarhizium/patogenicidade , Serratia marcescens/patogenicidade , Especificidade da Espécie , Análise de Sobrevida , Tenebrio/microbiologiaRESUMO
Serratia marcescens is a Gram-negative bacillus, anaerobic facultative belonging to the familyEnterobacteriaceae. S. marcescens strains are able to grow in the presence of different xenobiotic compounds,among them, petroleum and heavy metals. Xenobiotic resistant strains develop concomitant resistance tomultiple antibiotics, referred to as co-resistance. The AMS212 strain was submitted to the microplatequalitative DCPIP - redox 2,6 dichlorophenol indophenol method. The quantitative test was carried out inErlenmeyer flasks, followed by the change of color with the absorbance readings, trough the colorimetricmethod. The antibiotic resistance profile was evaluated by the Kirby-Bauer method. In the qualitativeassay, the AMS212 strain altered the color of the DCPIP, which changed from blue to colorless,confirming that petroleum biodegradation occurred. In the quantitative test, the readings were decreasing,confirming that the concentration of DCPIP decreased as a function of the incubation time. Thesusceptibility test revealed that the AMS212 strain presented multiresistance to four different antibiotics. S.marcescens presented high performance in the biodegradation of petroleum, opening possibility to use it inprojects involving the remediation of impacted areas. The expression of the antibiotic co-resistancephenotype confirms that the AMS212 strain is able to withstand different environmental aggressions.(AU)
Serratia marcescens é um bacilo Gram-negativo, anaeróbio facultativo, pertencente à famíliaEnterobacteriaceae. Linhagens de S. marcescens são capazes de crescer na presença de diferentes compostosxenobióticos, dentre eles, petróleo e metais pesados. Linhagens resistentes a xenobióticos desenvolvemconcomitante resistência a múltiplos antibióticos, denominada corresistência. A linhagem AMS212 foisubmetida ao método colorimétrico com indicador DCPIP - redox 2,6 diclorofenol indofenol, qualitativo,em microplacas. O teste quantitativo foi realizado em frascos Erlenmeyer, acompanhando-se a mudança decoloração, com as leituras das absorbâncias. Avaliou-se o perfil de resistência a antibióticos pelo método deKirby-Bauer. No ensaio qualitativo, a linhagem AMS212 alterou a cor do DCPIP, que passou de azul paraincolor, confirmando que ocorreu biodegradação do petróleo. No teste quantitativo, as leituras foramdecrescentes, confirmando que a concentração do DCPIP diminuiu em função do tempo de incubação. O testede susceptibilidade revelou que a linhagem AMS212 apresenta multirresistência a quatro antibióticos diferentes.S. marcescens apresentou alto desempenho na biodegradação do petróleo, abrindo possibilidade de utilizá-la emprojetos envolvendo a remediação de áreas impactadas. A expressão do fenótipo de corresistência a antibióticosconfirma que a linhagem AMS212 é capaz de resistir a diferentes agressões ambientais.(AU)
Assuntos
Biodegradação Ambiental , Serratia marcescens/química , Serratia marcescens/patogenicidade , Anti-InfecciososAssuntos
Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Serratia/microbiologia , Serratia marcescens/genética , beta-Lactamases/genética , Argentina/epidemiologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Infecções por Serratia/epidemiologia , Serratia marcescens/isolamento & purificação , Serratia marcescens/patogenicidadeRESUMO
Serratia marcescens is able to invade, persist, and multiply inside nonphagocytic cells, residing in nonacidic, nondegradative, autophagosome-like vacuoles. In this work, we have examined the physiological role of the PhoP/PhoQ system and its function in the control of critical virulence phenotypes in S. marcescens. We have demonstrated the involvement of the PhoP/PhoQ system in the adaptation of this bacterium to growth on scarce environmental Mg(2+), at acidic pH, and in the presence of polymyxin B. We have also shown that these environmental conditions constitute signals that activate the PhoP/PhoQ system. We have found that the two S. marcescens mgtE orthologs present a conserved PhoP-binding motif and demonstrated that mgtE1 expression is PhoP dependent, reinforcing the importance of PhoP control in magnesium homeostasis. Finally, we have demonstrated that phoP expression is activated intracellularly and that a phoP mutant strain is defective in survival inside epithelial cells. We have shown that the Serratia PhoP/PhoQ system is involved in prevention of the delivery to degradative/acidic compartments.
Assuntos
Proteínas de Bactérias/metabolismo , Infecções por Serratia/microbiologia , Serratia marcescens/metabolismo , Serratia marcescens/patogenicidade , Ácidos/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Sequência de Bases , Linhagem Celular , Regulação Bacteriana da Expressão Gênica , Humanos , Lisossomos/metabolismo , Lisossomos/microbiologia , Magnésio/metabolismo , Viabilidade Microbiana , Dados de Sequência Molecular , Alinhamento de Sequência , Serratia marcescens/genética , Serratia marcescens/crescimento & desenvolvimento , VirulênciaRESUMO
In Piura (Peru), the pest Phyllocnistis citrella Stainton damages the photosynthetic rate and new bud production of Citrus aurantiifolia Swingle (sweet lemon), decreasing the yield, productivity and commercial price of its fruit. Biological control was evaluated through the crossed effect of bacteria obtained from pests (Anastrepha fraterculus Wied., Ceratitis capitata Wied. and Rhynchophorus palmarum L.) that are pathogenic against their original host species. Enterobacter cloacae (Jordan) Hormaeche & Edwards and Serratia marcescens Bizio (from A. fraterculus and C. capitata) and Pseudomonas mendocina Palleroni (from R. palmarum) were used against P. citrella. The bacterial strains were inoculated into its food and the accumulated mortality was evaluated. Larvae of P. citrella treated with P. mendocina had the highest mortality (66.7%). These bacterial species were entomopathogenic against the original source pest in laboratory and greenhouse bioassays, and this result widens the pathological activity range of these bacterial species.
Assuntos
Ceratitis capitata/microbiologia , Mariposas/microbiologia , Controle Biológico de Vetores , Tephritidae/microbiologia , Animais , Enterobacter cloacae/patogenicidade , Pseudomonas mendocina/patogenicidade , Serratia marcescens/patogenicidadeRESUMO
Studies were carried out on the effects of different carbohydrates on the lysis of Trypanosoma cruzi, Trypanosoma rangeli and erythocytes caused by the bacteria Serratia marcescens variants SM 365 and RPH. High concentrations of d-mannose were found to protect T. cruzi and T. rangeli markedly diminishing the lysis caused by S. marcescens. However, this carbohydrate is unable to interfere with the hemolysis induced by SM 365 and RPH variants. These results showed that the trypanolytic effect induced by S. marcescens SM 365 and RPH variants is dependent on d-mannose and distinct from the hemolytic activity, strongly suggesting that bacterial fimbriae are relevant to S. marcescens in lysis of parasites.
Assuntos
Hemólise/efeitos dos fármacos , Manose/fisiologia , Serratia marcescens/fisiologia , Trypanosoma cruzi/metabolismo , Animais , Eritrócitos/efeitos dos fármacos , Eritrócitos/microbiologia , Fímbrias Bacterianas/fisiologia , Humanos , Cinética , Manose/farmacologia , Serratia marcescens/efeitos dos fármacos , Serratia marcescens/patogenicidade , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/microbiologiaRESUMO
OBJECTIVE: To investigate an apparent outbreak involving simultaneous isolation of Pseudomonas aeruginosa and Serratia marcescens from bronchoalveolar lavage (BAL) samples. DESIGN: Retrospective and prospective cohort studies using chart review, environmental sampling, and ribotyping of all available isolates. Cleaning and disinfection procedures for the bronchoscopes were also evaluated. SETTING: A 380-bed private hospital in São Paulo, Brazil PATIENTS: Forty-one patients who underwent bronchoscopic procedures between December 1994 and October 1996 and from whom P. aeruginosa and S. marcescens were concomitantly isolated. Bronchoscopes and related items were microbiologically assessed. RESULTS: P. aeruginosa and S. marcescens were simultaneously isolated from BAL samples 12.6% of the time (41 of 324) during the epidemic period versus 1.8% of the time (1 of 54) in the pre-epidemic period (P = .035). Ribotyping revealed two strains of P. aeruginosa and one of S. marcescens that were isolated from BAL samples of patients with no signs of respiratory tract infection, suggesting a pseudo-outbreak. Evaluation of bronchoscope disinfection revealed that inappropriate methods were being used. Implementation of simple control measures resulted in a significant decrease in simultaneous isolation of these species. CONCLUSION: Prevention of pseudo-outbreaks requires meticulous use of preventive measures for infection-prone medical procedures.
Assuntos
Broncoscópios/microbiologia , Broncoscopia/efeitos adversos , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/etiologia , Surtos de Doenças , Contaminação de Equipamentos , Infecções por Pseudomonas/transmissão , Pseudomonas aeruginosa/isolamento & purificação , Infecções por Serratia/transmissão , Serratia marcescens/isolamento & purificação , Brasil/epidemiologia , Lavagem Broncoalveolar , Estudos de Coortes , Desinfecção/métodos , Reutilização de Equipamento , Hospitais Privados , Humanos , Estudos Prospectivos , Pseudomonas aeruginosa/patogenicidade , Estudos Retrospectivos , Ribotipagem , Serratia marcescens/patogenicidadeRESUMO
In this work, culture filtrates of entomopathogenic and phytopathogenic Serratia marcescens strains induced cytotoxic effects on CHO, Vero and HEp-2 cell lines. Morphological changes on sensitive cells were characterized by cell rounding and detachment as soon as 30 min of incubation, culminating in cell death after 24 h. The cytotoxic effect was completely neutralized by specific antiserum indicating that occur antigenic similarity among cytotoxins produced by these strains. The toxicity assays on plants showed that the culture supernatants did not provoke any visible morphological change and did not affect their growth. By contrast, the plants treated with bacterial suspension showed disease symptom, such as shriveling and decay of stores bulbus in onion and lettuce plantlets. In conclusion, this study show that phytopathogenic and entomopathogenic S. marcescens may produce a cytototoxin similar to that produced by clinical isolates and it is toxic to different mammalian cell lines. These results are especially important for studies involving this bacterium as biological control agent.
Assuntos
Citotoxinas/biossíntese , Lactuca/microbiologia , Mariposas/microbiologia , Cebolas/microbiologia , Serratia marcescens/metabolismo , Animais , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/imunologia , Células CHO/efeitos dos fármacos , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral/efeitos dos fármacos , Chlorocebus aethiops , Cricetinae , Cricetulus , Citotoxinas/toxicidade , Feminino , Humanos , Lactente , Neoplasias Laríngeas/patologia , Testes de Neutralização , Doenças das Plantas , Coelhos , Serratia marcescens/patogenicidade , Células Vero/efeitos dos fármacosRESUMO
Pigmented Serratia marcescens isolated in a Brazilian hospital were studied with respect to frequency of isolation, serotyping, antibiotic resistance and virulence factors. The serotype most frequent was O6:K14 (53%) and all isolates were resistant to ampicillin, cephalothin and tetracycline. The majority of the isolates (92%) were resistant to the action of human serum and all produced cytotoxins on Vero, CHO, HEp-2 and HeLa cells. These isolates were virulent for mice (LD(50)=10(7) bacteria ml(-1)) and showed virulence factors, but were isolated with low frequency (3. 4%) and caused infection in only 31% of cases. Analysis of serotyping, phage typing and chromosomal DNA revealed at least 13 unrelated strains among pigmented S. marcescens. In conclusion, this work describes a low frequency of isolation of pigmented S. marcescens from clinical specimens, indicating that non-pigmented strains are clinically more significant.
Assuntos
Infecções por Serratia/microbiologia , Serratia marcescens/patogenicidade , Animais , Antibacterianos/farmacologia , Brasil/epidemiologia , Células CHO , Chlorocebus aethiops , Cricetinae , Infecção Hospitalar/microbiologia , Citotoxinas/metabolismo , Eletroforese em Gel de Campo Pulsado , Feminino , Células HeLa , Humanos , Camundongos , Plasmídeos , Infecções Respiratórias/microbiologia , Sorotipagem , Infecções por Serratia/epidemiologia , Serratia marcescens/genética , Células Vero , VirulênciaAssuntos
Serratia marcescens/isolamento & purificação , Serratia marcescens/patogenicidade , Testes de Sensibilidade Microbiana , Testes de Sensibilidade Microbiana/instrumentação , Técnicas de Tipagem Bacteriana/instrumentação , Infecções por Serratia/etiologia , Infecções por Serratia/microbiologia , AntibacterianosRESUMO
Serratia marcescens has been reported as an organism which can cause rapidly spreading, antibiotic resistant nosocomial colonization and disease. We report here an outbreak of colonization and disease due to S. marcescens involving 53 infants admitted to the Neonatal Intensive Care Unit (NICU) of the Uberlândia Federal University Hospital, Brazil, between December, 1997, and April, 1998. Thirty-eight infants were colonized without clinical signs of infection and 15 infants had clinical disease. Five infants developed septicemia (4 cases were fatal, including the presumed index case). Seven infants developed conjunctivitis, 1 developed both sepis and conjunctivitis, 1 infant developed otitis, and 1 infant had a urinary tract infection. On univariate analysis, independent risk factors for S. marcescens clinical disease were: low birth weight (<1.500g), incubator care, use carbapenems, duration of hospitalization (maior igual que 7 days), low Apgar score, and prematurity. All the isolates of S. marcescens showed the same antimicrobial susceptibility profile. The causative strains were resistant to oxyimino-cephalosporins due to their production of extended-spectrum ß-lactamases. Cultures from the hands of the NICU health care professionals (HCWs), soap samples, ventilator reservoirs, and work and incubator surfaces failed to identify a reservoir of S. marcescens, but positive cultures were found in half of the sink drains. Containment of the outbreak was achieved by closure of the NICU new admissions, employment of strict hygienic measures, and careful nursing care of the infected and colonized infants. Rapid organism identification and initiation of control measures are important in containing such an epidemic at an early stage.
Assuntos
Humanos , Recém-Nascido , Infecção Hospitalar/epidemiologia , Controle de Infecções , Unidades de Terapia Intensiva Neonatal , Resistência Microbiana a Medicamentos , Sepse/mortalidade , Serratia marcescens/isolamento & purificação , Serratia marcescens/patogenicidade , Estudos de Casos e Controles , Poluição Ambiental , Fatores de RiscoRESUMO
Cytotoxin production was studied in 60 Serratia marcescens strains isolated from hospitalized patients. Association of cytotoxic activity with serotype, source of isolation and presence of plasmids was also evaluated. Thirteen of the 60 S. marcescens strains produced a cytotoxic effect of Vero cells. These strains were isolated from distinct clinical sources and classified into seven different serotypes (O1:H7; O4:NM; O10:NT; O19:NM; O6,14:H4; O6,14:NM and O6,14:H1). No relationship was observed between cytotoxic activity and clinical source or serotypes of the strains. Plasmids from five cytotoxin-producing S. marcescens strains were transferred to E. Coli K12/711. The transconjugants did not exhibit cytotoxicity, indicating that the cytotoxic effect is not plasmid-mediated among these strains. Although a cytotoxic activity was demonstrated in filtrates of some S. marcescens strains, further studies should be performed to assess the role of this toxin in pathogenesis.
Assuntos
Humanos , Citotoxinas , Técnicas In Vitro , Serratia marcescens/isolamento & purificação , Serratia marcescens/patogenicidade , Células Vero/patologiaRESUMO
Mice pre-treated with Concanavalin-A largely survived an intra-peritoneal inoculum of 2 x 10(7) Serratia marcescens, whereas all control mice died within 15 h of inoculation. A subpopulation of peritoneal macrophages from Con-A pre-treated mice was able to phagocytose the bacteria in vitro (6.7 SEM 1.2% phagocytosing cells) and in vivo (16.9 SEM 2.1%), whereas control phagocytes did not phagocytose S. marcescens. The survival of Con-A pre-treated mice allowed their immunisation with living bacteria, and the antiserum thus produced increased the phagocytosis of S. marcescens in vitro. Control mice largely survived an inoculum of S. marcescens suspended in 50% immune serum, although the bacteria were resistant to the bactericidal activity of that serum. These results suggest that, in contrast to the delayed humoral protection afforded by immunisation, phagocytosis by phagocytes activated by Con-A conferred early protection to mice against experimental infection by S. marcescens.
Assuntos
Concanavalina A/farmacologia , Doenças Peritoneais/imunologia , Infecções por Serratia/imunologia , Serratia marcescens/imunologia , Animais , Atividade Bactericida do Sangue , Concanavalina A/uso terapêutico , Soros Imunes/análise , Soros Imunes/imunologia , Imunidade Celular/efeitos dos fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/imunologia , Camundongos , Doenças Peritoneais/prevenção & controle , Fagocitose/efeitos dos fármacos , Infecções por Serratia/prevenção & controle , Serratia marcescens/patogenicidade , VirulênciaRESUMO
Cytotoxin production was studied in 60 Serratia marcescens strains isolated from hospitalized patients. Association of cytotoxic activity with serotype, source of isolation and presence of plasmids was also evaluated. Thirteen of the 60 S. marcescens strains produced a cytotoxic effect on Vero cells. These strains were isolated from distinct clinical sources and classified into seven different serotypes (O1:H7; O4:NM; O10:NT; O19:NM; O6,14:H4; O6,14:NM and O6,14:H1). No relationship was observed between cytotoxic activity and clinical source or serotypes of the strains. Plasmids from five cytotoxin-producing S. marcescens strains were transferred to E. coli K12/711. The transconjugants did not exhibit cytotoxicity, indicating that the cytotoxic effect is not plasmid-mediated among these strains. Although a cytotoxic activity was demonstrated in filtrates of some S. marcescens strains, further studies should be performed to assess the role of this toxin in pathogenesis.
Assuntos
Citotoxinas , Serratia marcescens/patogenicidade , Células Vero , Animais , Chlorocebus aethiops , HumanosRESUMO
El objetivo del presente trabajo es la exposición de lo que se considera el primer caso de peritonitis en un paciente con diálisis peritoneal continua ambulatoria (DPCA) -por insuficiencia renal crónica terminal-causada por Serratia marcescens y tratado exitosamente con carbenicilina. Se trata de un bacilo gramnegativo, móvil, aerobio, miembro de la división Klebsiella-Enterobacter-Serratia, entre la familia enterobacteriaceae. La Serratia contrasta con otros bacilos enterobacteriaceos en que no es huésped habitual del tracto digestivo y se adquiere por contaminación iatrógena como manipulación genitourinaria, diálisis peritoneal, hemodialisis y punción lumbar. Su tratamiento antibiótico es difícil pues presenta gran resistencia medicamentosa por plásmidos