scholarly journals Oxygen restriction generates difficult-to-culture pathogens

2018 ◽  
Author(s):  
Lasse Kvich ◽  
Blaine G. Fritz ◽  
Stephanie Crone ◽  
Kasper N. Kragh ◽  
Mette Kolpen ◽  
...  

AbstractInduction of a non-culturable state has been demonstrated for many bacteria. In a clinical perspective, the lack of growth due to these non-culturable bacteria can have major consequences for the diagnosis and treatment of patients. Here we show how anoxic conditioning (restriction of molecular oxygen, O2) generates difficult-to-culture (DTC) bacteria during biofilm growth. A significant subpopulation of Pseudomonas aeruginosa entered a DTC state after anoxic conditioning, ranging from five to 90 % of the total culturable population, in both planktonic and biofilm models. Anoxic conditioning also generated DTC subpopulations of Staphylococcus aureus and Staphylococcus epidermidis. Growth of the DTC populations were achieved by substituting O2 with 10 mM NO3- as an alternative electron acceptor for anaerobic respiration or, in the case of P. aeruginosa, by adding sodium pyruvate or catalase as scavengers against reactive oxygen species (ROS) during aerobic respiration. An increase in normoxic plating due to addition of catalase suggests the molecule hydrogen peroxide as a possible mechanism for induction of DTC P. aeruginosa. Anoxic conditioning also generated a true viable but non-culturable (VBNC) population of P. aeruginosa that was not resurrected by substituting O2 with NO3- during anaerobic respiration. Moreover, bacterial detection in clinical samples was improved significantly by supplementing 10 mM NO3- to LB plates and incubating under anoxic conditions. These results demonstrate that habituation to an infectious anoxic micro-environment complicates diagnostic culturing of bacteria, especially in the case of chronic infections where oxygen is restricted due to the host immune response.ImportanceDiagnostics of bacteria from chronic infections by standard culture-based methods is challenging. Bacteria in a non-culturable state may contribute to the lack of culturing from these infections. Many stressors are known to induce a non-culturable state, among others the absence of molecular oxygen, which is evident in chronic infections due to high rates of oxygen consumption by the host response. In this study, we have shown that Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis can enter a difficult-to-culture state after oxygen restriction. Regrowth was not possible using conventional normoxic plating where oxygen served as electron acceptor. Instead, regrowth was enabled during anoxic conditions with added nitrate as alternative electron acceptor. Our findings show that bacteria can habituate to their environment and that it has to be taken into consideration especially when culturing clinical samples e.g. from chronic infections.

2020 ◽  
Vol 202 (18) ◽  
Author(s):  
Giulia Orazi ◽  
Fabrice Jean-Pierre ◽  
George A. O’Toole

ABSTRACT The thick mucus within the airways of individuals with cystic fibrosis (CF) promotes frequent respiratory infections that are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent pathogens that cause CF pulmonary infections, and both are among the most common etiologic agents of chronic wound infections. Furthermore, the ability of P. aeruginosa and S. aureus to form biofilms promotes the establishment of chronic infections that are often difficult to eradicate using antimicrobial agents. In this study, we found that multiple LasR-regulated exoproducts of P. aeruginosa, including 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), siderophores, phenazines, and rhamnolipids, likely contribute to the ability of P. aeruginosa PA14 to shift S. aureus Newman norfloxacin susceptibility profiles. Here, we observe that exposure to P. aeruginosa exoproducts leads to an increase in intracellular norfloxacin accumulation by S. aureus. We previously showed that P. aeruginosa supernatant dissipates the S. aureus membrane potential, and furthermore, depletion of the S. aureus proton motive force recapitulates the effect of the P. aeruginosa PA14 supernatant on shifting norfloxacin sensitivity profiles of biofilm-grown S. aureus Newman. From these results, we hypothesize that exposure to P. aeruginosa PA14 exoproducts leads to increased uptake of the drug and/or an impaired ability of S. aureus Newman to efflux norfloxacin. Surprisingly, the effect observed here of P. aeruginosa PA14 exoproducts on S. aureus Newman susceptibility to norfloxacin seemed to be specific to these strains and this antibiotic. Our results illustrate that microbially derived products can alter the ability of antimicrobial agents to kill bacterial biofilms. IMPORTANCE Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from multiple infection sites, including the lungs of individuals with cystic fibrosis (CF) and nonhealing diabetic foot ulcers. Coinfection with P. aeruginosa and S. aureus has been shown to produce worse outcomes compared to infection with either organism alone. Furthermore, the ability of these pathogens to form biofilms enables them to cause persistent infection and withstand antimicrobial therapy. In this study, we found that P. aeruginosa-secreted products dramatically increase the ability of the antibiotic norfloxacin to kill S. aureus biofilms. Understanding how interspecies interactions alter the antibiotic susceptibility of bacterial biofilms may inform treatment decisions and inspire the development of new therapeutic strategies.


2015 ◽  
Vol 17 (4 suppl 3) ◽  
pp. 1142-1149 ◽  
Author(s):  
J.A.L MIRANDA ◽  
J.A. ROCHA ◽  
K.M. ARAÚJO ◽  
P.V. QUELEMES ◽  
S.J. MAYO ◽  
...  

RESUMO O uso de plantas medicinais no tratamento de doenças é uma estratégia antiga utilizada por praticamente todas as populações do mundo, e, embora novos antibióticos tenham sido desenvolvidos para o controle de micro-organismos infecciosos, às vezes são ineficazes. Diversos extratos de plantas medicinais têm efeitos antimicrobianos, principalmente quando associados à antibióticos de uso clínico, representando alternativa terapêutica para doenças infecciosas. Montrichardia linifera, conhecida popularmente como aninga, é espécie macrófita, aquática emergente de hábito herbáceo, pertencente a família Araceae e ocorre em áreas alagáveis. A utilidade farmacológica desta espécie é diversificada tendo sido relatada como cicatrizante, antirreumático, antidiurético e expectorante. Devido à relevância no campo etnofarmacológico, ampla utilização na medicina popular e escassez de trabalhos relacionados à atividade antibacteriana desta espécie, objetivou-se com este trabalho avaliar a atividade antibacteriana de extratos alcoólicos de folhas de Montrichardia linifera, coletadas na margem do rio Igaraçu, Parnaíba-PI. O extrato foi testado em oito cepas de bactérias: Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae e Pseudomonas aeruginosa. Foram utilizadas as técnicas de verificação da formação de halos de inibição e determinação das concentrações inibitórias e bactericidas mínimas. Os testes antibacterianos evidenciaram como principais resultados que o extrato metanólico seco (EMS), extrato metanólico fresco (EMF), e o extrato etanólico seco (EES), apresentaram ação antibacteriana, enquanto o extrato etanólico fresco (EEF) não apresentou atividade para as bactérias testadas. O EMS foi o mais eficiente, inibindo o crescimento bacteriano na concentração de 200 μg/mL para E. faecalis, 400 μg/mL para S. aureus, 400 μg/mL para S. epidermidis e 2.000 μg/mL para P. aeruginosa. O EMF obteve CIM de 2.000 μg/mL para E. faecalis e EES obteve CIM de 250 μg/mL para E. faecalis. Os resultados demonstraram que M. linifera constitui fonte eficiente de compostos bioativos antibacterianos. Os estudos sobre as propriedades farmacológicas de plantas da família Araceae são escassos, e os resultados deste trabalho são pioneiros em relação a atividade antibacteriana desta espécie.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Artur J. Sabat ◽  
Daniele Pantano ◽  
Viktoria Akkerboom ◽  
Erik Bathoorn ◽  
Alexander W. Friedrich

Abstract The gold standard for the diagnosis of bacterial infections in clinical samples is based on culture tests that are time-consuming and labor-intense. For these reasons, an extraordinary effort has been made to identify biomarkers as the tools for sensitive, rapid and accurate identification of pathogenic microorganisms. Moreover, biomarkers have been tested to distinguish colonization from infection, monitor disease progression, determine the clinical status of patients or predict clinical outcomes. This mini-review describes Pseudomonas aeruginosa and Staphylococcus aureus biomarkers, which contribute to pathogenesis and have been used in culture-independent bacterial identification directly from patient samples.


Author(s):  
Miladys Esther Torrenegra Alarcón ◽  
Nerlis Paola Pájaro ◽  
Glicerio León Méndez

Se evaluó la actividad antibacteriana in vitro de aceites esenciales de diferentes especiesdel género Citrus frente a cepas ATCC de Staphylococcus aureus, Staphylococcus epidermidis,Klebsiella pneumoniae, Pseudomonas aeruginosa y Escherichia coli, determinandola concentración mínima inhibitoria (CMI) y la concentración mínima bactericida(CMB). Las bacterias se replicaron en medios de agar y caldos específicos. Se determinóel momento de máxima densidad óptica (DO620) para emplearlo como tiempode incubación; luego se hicieron pruebas de evaluación de sensibilidad con la exposiciónde las cepas a concentraciones a 1000 g/mL del extracto en caldo. Para solubilizarse empleó dimetilsulfóxido (DMSO) al 1%. Posteriormente, se le determinó laconcentración mínima inhibitoria mediante metodologías de microdilución en caldoy la concentración mínima bactericida. Encontrándose una actividad de los aceitesesenciales del género Citrus, con valores de CMI ≥ 600 mg/mL frente a S. aureus,S. epidermidis, K. pneumoniae, P. aeruginosa y E. coli. En función a los resultados obtenidos,se concluye que las diferentes especies del género Citrus son consideradas comopromisorias para el control del componente bacteriano.


2001 ◽  
Vol 2 (1) ◽  
Author(s):  
Ana Marcia De Matos Volpato ◽  
Ester De Moura Rios ◽  
Marilis Dallarmi Miguel ◽  
Paulo Cesar Sander ◽  
Obdúlio Gomes Miguel

A atividade antimicrobiana de Calendula officinalis L. (Asteraceae) já foi cientificamente comprovada em outros países. O objetivo deste trabalho foi avaliar a atividade antibacteriana de C. officinalis cultivada no Paraná - Brasil, nas condições de extração etanólica 50%, com filtração e partições sucessivas com hexano, diclorometano, acetato de etila e butanol, frente a cepas Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228 e Bacillus cereus, pela técnica da difusão em meio sólido por cavidade e posteriormente pelo método de diluição em placa. Os resultados demonstraram que algumas frações do extrato inibiram as bactérias gram-positivas, com atividade frente a Staphylococcus e Bacilos e inexiste em gram negativas, indicando que o princípio ativo responsável pela atividade antibacteriana observada possa ser isolado a partir das frações Hexânica e DCM nas condições de extração propostas neste trabalho. Abstract The Calendula officinalis L. (Asteraceae) antimicrobial action has already been scientifically proved in other countries. The aim of this study was to assess the antibacterial action of the Callendula officinalis which is grown in Paraná - Brasil, under extraction conditions at ethanol 50%, with filtration and successive partitions with hexane, dichloromethane, ethyl acetate and butane, contrasting with strains Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228 and Bacilus cereus, by the difusion technique in solid media by cavity and afterwards by the plaque dilution method. The results showed that some fractions of the extract inhibited the gram-prositive bacteria, with activity in contrast with Staphylococcus and Bacillus and non-existing in gram-negative, also indicating that the active ingredient responsible for the antibacterial action observed can be isolated from the Hexanic and DCM fractions under the extraction conditions proposed in this study.


2014 ◽  
Vol 58 (8) ◽  
pp. 4353-4361 ◽  
Author(s):  
Carlos J. Sanchez ◽  
Kevin S. Akers ◽  
Desiree R. Romano ◽  
Ronald L. Woodbury ◽  
Sharanda K. Hardy ◽  
...  

ABSTRACTWithin wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluatedin vitrothe dispersive activity ofd-amino acids (d-AAs) on biofilms from clinical wound isolates ofStaphylococcus aureusandPseudomonas aeruginosa; moreover, we determined whether combinations ofd-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin forS. aureusand amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime forP. aeruginosa) enhance activity against biofilms.d-Met,d-Phe, andd-Trp at concentrations of ≥5 mM effectively dispersed preformed biofilms ofS. aureusandP. aeruginosaclinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (d-Met/d-Phe/d-Trp). When combined withd-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates ofS. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition ofd-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms ofP. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity ofd-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity.


2012 ◽  
Vol 15 (2) ◽  
pp. 78-83
Author(s):  
Reider Vivanco T ◽  
Enrique León S ◽  
Américo Castro L ◽  
Norma J Ramos C

El estudio tuvo como objetivo analizar la composición química del aceite esencial de las hojas de Petroselinum crispum (Mill) Nyman ex A.W. Hill “perejil” y determinar su actividad antibacteriana. El aceite esencial se obtuvo tratando 20 kg de hojas frescas con un equipo de destilación por arrastre con vapor de agua; obteniéndose cuatro mililitros y un rendimiento de 0,02 por ciento v/p. En el análisis cualitativo se analizó su solubilidad en solventes orgánicos; los componentes químicos se determinaron por cromatografía de Gases/ Espectrometría de Masas (CG/EM), lográndose la elucidación de los siguientes compuestos: 1R-α-pineno, β-pineno, β-felandreno, p, α-dimetil estireno, (E)-2-caren-4-ol, 1,3-benzodioxol, 4-metoxi-6-(2-propenil)-, y 1,3-benzodioxol,4,7-dimetoxy-5-(2-propenil)-. La determinación de la actividad antibacteriana in vitro, se realizó por el método de difusión en agar, demostrándose actividad significativa frente a Staphylococcus aureus ATCC 25933 y Staphylococcus epidermidis cepa clínica, a las concentraciones de 100 y 50 por ciento; y para Pseudomonas aeruginosa ATCC 2783 a la concentración de 100 por ciento, teniendo de poca a ninguna actividad frente a Bacillus subtilis y Escherichia coli. Los resultados obtenidos muestran que el aceite esencial de Petroselinum crispum (Mill) Nyman ex A.W. Hill “perejil” presenta actividad antibacteriana.


2019 ◽  
Vol 8 (3) ◽  
pp. 553
Author(s):  
Narlis Narlis ◽  
Ellyza Nasrul ◽  
Efrida Efrida

Community acquired pneumonia (CAP) merupakan infeksi yang paling sering menyebabkan sepsis dan dapat menimbulkan kematian. Pertimbangan pemilihan antimikroba yang tepat dan menghindari penggunaan yang berlebihan perlu dilakukan untuk mencegah terjadinya resistensi. Tujuan penelitian ini adalah mengetahui pola kuman dan uji kepekaan pasien CAP di RSUP Dr. M. Djamil Padang. Penelitian ini merupakan penelitian deskriptif retrospektif terhadap 201 sampel sputum pasien CAP yang diperiksa kultur kemudian dilanjutkan dengan pewarnaan Gram dan uji biokimia untuk mengidentifikasi bakteri. Uji kepekaan antimikroba menggunakan metode difusi cakram. Penelitian dilakukan di Laboratorium Sentral RSUP Dr. M. Djamil Padang periode Januari 2016 hingga Desember 2016. Data ditampilkan dalam bentuk tabel distribusi frekuensi. Mikroorganisme yang ditemukan adalah Klebsiella pneumonia (55,23%), Staphylococcus aureus (25,87%), Streptococcus pneumonia (7,96%), Pseudomonas aeruginosa (5,97%), Staphylococcus epidermidis (2,9%), Acinetobacter baumani (1,99%), Proteus vulgaris (0,49%). Antimikroba yang paling sensitif adalah Meropenem (78,7%), sedangkan antimikroba resisten dengan persentase tertinggi adalah Ampisilin (90%), Amoksisilin (89,4%), Eritromisin (73,5%), Amoksisilin + Klavulanat (64,6%), dan Kloramfenikol (61,7%). Mikroorganisme yang paling banyak ditemukan adalah Klebsiella pneumonia (55,23%). Meropenem merupakan antimikroba sensitif dengan persentase paling tinggi (78,7%) sedangkan antimikroba resisten dengan persentase paling tinggi adalah ampisilin (90%).


2021 ◽  
Vol 10 (2) ◽  
pp. e20310212241
Author(s):  
Jeisa Patricia Leitzke ◽  
Tatiany Alves Nierri ◽  
Jaqueline Hoscheid ◽  
Nathielle Miranda

Os sabonetes em barra com ação antisséptica são destinados à limpeza de resíduos presentes no corpo, sua utilização tem crescido significativamente em decorrência da preocupação da população com determinadas doenças causadas por contaminação microbiológica. Com isso, têm surgido no mercado diferentes marcas de sabonetes garantindo a eliminação de 99,9% das bactérias. O objetivo deste estudo foi realizar a análise comparativa do pH, atividade antibacteriana e rótulos de 5 diferentes marcas de sabonetes antibacterianos em barra, identificados como A, B, C D e E. Realizou-se a determinação do pH com auxílio de pHmetro digital, e na análise microbiológica utilizou-se a metodologia de disco difusão, com o intuito de observar a presença ou ausência da multiplicação das bactérias Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus e Escherichia coli frente aos diferentes sabonetes testados. Durante a análise da rotulagem dos sabonetes foi avaliada a presença do requisito “composição”, exigido pela resolução vigente.  Nos testes realizados constatou-se que o pH de todas as marcas testadas encontraram-se fora dos parâmetros estabelecidos. Na análise microbiológica observou-se que apenas a marca E, demonstrou efeito antisséptico frente às bactérias testadas. Os demais sabonetes apresentaram menor e até mesmo nenhum potencial de inibição do crescimento desses microrganismos. Os produtos analisados neste estudo apresentam em suas formulações duas substâncias ativas, o triclosan e o triclocarban, porém os mesmos podem ser nocivos para a saúde humana e meio ambiente, e induzirem a resistência bacteriana, por isso, alguns países já proibiram o uso destes ativos. Segundo os resultados obtidos é possível concluir que os rótulos presentes das embalagens destas diferentes marcas analisadas estão em desacordo com o estabelecido pelos fabricantes.


2014 ◽  
Vol 3 (3) ◽  
Author(s):  
Ashima Sonita ◽  
Erly Erly ◽  
Machdawaty Masri

AbstrakPeningkatan resistensi bakteri penyebab PPOK terhadap beberapa antibiotika yang lazim digunakan oleh klinisi dalam pemberian terapi empirik akan menyebabkan berkurangnya keefektifan terhadap terapi PPOK. Hal ini akan berdampak semakin tingginya morbiditas dan mortalitas yang disebabkan oleh PPOK. Penelitian ini bertujuan untuk mengetahui pola resistensi bakteri penyebab PPOK terhadap beberapa antibiotika di Laboratorium Mikrobiologi RSUP.Dr.M.Djamil periode 2010 – 2012. Penelitian ini telah dilaksanakan pada bulan November 2013 sampai dengan Desember 2013 di Laboratotium Mikrobiologi RSUP Dr.M.Djamil Padang. Metode penelitian yang digunakan adalah deskriptif retrospektif. Hasil penelitian mendapatkan bakteri penyebab PPOK adalah Klebsiella spp (42,44%), Streptococcus α hemolyticus (38,37%), Pseudomonas aeruginosa (12,21%), Staphylococcus aureus (4,65%), Proteus mirabilis (1,16%), Staphylococcus epidermidis (0,58%) dan Streptococcus pneumoniae (0,58%). Disimpulkan bahwa bakteri tersering pada sputum pasien PPOK adalah Klebsiella spp. Tingkat resistensi tertinggi adalah Ampicillin, sedangkan tingkat kepekaan tertinggi adalah terhadap Netilmycin.Kata kunci: antibiotika, bakteri, resistensiAbstractIncreased resistance of bacteria that cause COPD to some antibiotics that are commonly used by clicicians in the provision of empiric therapy, it will cause a reduction in the effectiveness of the tratment of COPD. This study aimed to determine the resistance pattern of Bacteria in sputum of patients COPD to some antibiotics in Microbiology Laboratory Dr.M.Djamil Hospital Peroid 2010 – 2012. The research method was a descriptive and retrospective. According to the result, the bacteria that causes COPD is Klebsiella spp (42.44%), Streptococcus α hemolyticus (38.37%), Pseudomonas aeruginosa (12.21%), Staphylococcus aureus (4.65%), Proteus mirabilis (1.16%), Staphylococcus epidermidis (0.58%), and Streptococcus pneumoniae (0.58%). It can be concluded that the bacteria which cause the highest number of COPD is Klebsiella sp. The highest level of resistance is ampicillin while the highest level of sensitivity Is netilmycin.Keywords: antibiotics, bacteria, resistance


Sign in / Sign up

Export Citation Format

Share Document