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AIMS: Investigated and compared the occurrence of virulence genes fimH, mrkD, irp2, entB, cps, rmpA, and wabG, resistance genes blaKPC and blaNDM, and the genetic variability and clonal relationship of 29 Klebsiella pneumoniae clinical isolates of patients with and without COVID-19, from a hospital in Brazil. METHODS AND RESULTS: All isolates were resistant to beta-lactams. The genes were investigated by PCR, and for molecular typing, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and MLST were used. The detection of blaNDM was greater (n = 23) when compared to that of blaKPC (n = 14). The virulence genes that most occurred were fimH, entB, cps, and wabG, which are responsible for adhesins, siderophore enterobactin, capsule, and lipopolysaccharides, respectively. Among the isolates, 21 distinct genetic profiles were found by ERIC-PCR, with multiclonal dissemination. Four isolates belonged to the ST11 clone. CONCLUSIONS: The occurrence of the ST11 is worrying as it is a high-risk clone involved in the dissemination of virulent strains throughout the world.
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COVID-19 , Infecciones por Klebsiella , Klebsiella pneumoniae , SARS-CoV-2 , beta-Lactamasas , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/patogenicidad , Brasil , Humanos , Infecciones por Klebsiella/microbiología , COVID-19/microbiología , beta-Lactamasas/genética , SARS-CoV-2/genética , Virulencia/genética , Antibacterianos/farmacología , Tipificación de Secuencias Multilocus , Pruebas de Sensibilidad Microbiana , Factores de Virulencia/genéticaRESUMEN
AIMS: To investigate the genetic profile and characterize antimicrobial resistance, including the main ß-lactam antibiotic resistance genes, in Acinetobacterbaumannii isolates from a tertiary hospital in Recife-PE, Brazil, in the post-COVID-19 pandemic period. METHODS AND RESULTS: Acinetobacter baumannii isolates were collected between 2023 and 2024 from diverse clinical samples. Antimicrobial resistance testing followed standardized protocols, with ß-lactamase-encoding genes detected via PCR and sequencing. Investigation into ISAba1 upstream of blaOXA-carbapenemase and blaADC genes was also conducted. Genetic diversity was assessed through ERIC-PCR. Among the 78 A. baumannii, widespread resistance to multiple antimicrobials was evident. Various acquired ß-lactamase-encoding genes (blaOXA-23,-24,-58,-143, blaVIM, and blaNDM) were detected. Furthermore, this is the first report of blaVIM-2 in A. baumannii isolates harboring either the blaOXA-23-like or the blaOXA-143 gene in Brazil. Molecular typing revealed a high genetic heterogeneity among the isolates, and multi-clonal dissemination. CONCLUSION: The accumulation of genetic resistance determinants underscores the necessity for stringent infection control measures and robust antimicrobial stewardship programs to curb multidrug-resistant strains.
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Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , COVID-19 , Pruebas de Sensibilidad Microbiana , SARS-CoV-2 , Centros de Atención Terciaria , beta-Lactamasas , Acinetobacter baumannii/genética , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Brasil , Humanos , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/epidemiología , beta-Lactamasas/genética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , SARS-CoV-2/genética , Farmacorresistencia Bacteriana Múltiple/genética , Proteínas Bacterianas/genética , Masculino , Adulto , Femenino , Persona de Mediana Edad , Farmacorresistencia Bacteriana/genéticaRESUMEN
AIMS: Determine which sequence type (ST) clones were carrying the blaKPC, blaNDM, blaVIM, blaIMP, and blaGES genes and their variants in clinical isolates of multidrug-resistant Klebsiella pneumoniae. METHODS AND RESULTS: Ten K. pneumoniae isolates were obtained from the colonized and infected patients in a public hospital in the city of Recife-PE, in northeastern Brazil, and were further analyzed. The detection of carbapenem resistance genes and the seven housekeeping genes [for multilocus sequence typing (MLST) detection] were done with PCR and sequencing. The blaKPC and blaNDM genes were detected concomitantly in all isolates, with variants being detected blaNDM-1, blaNDM-5, blaNDM-7, and blaKPC-2. The blaKPC-2 and blaNDM-1 combination being the most frequent. Molecular typing by MLST detected three types of high-risk ST clones, associated with the clonal complex 258, ST11/CC258 in eight isolates, and ST855/CC258 and ST340/CC258 in the other two isolates. CONCLUSIONS: These findings are worrying, as they have a negative impact on the scenario of antimicrobial resistance, and show the high genetic variability of K. pneumoniae and its ability to mutate resistance genes and risk of dissemination via different ST clones.
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Klebsiella pneumoniae , beta-Lactamasas , Humanos , Klebsiella pneumoniae/genética , Tipificación de Secuencias Multilocus , beta-Lactamasas/genética , Brasil/epidemiología , Células Clonales , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacologíaRESUMEN
INTRODUCTION: Proteus mirabilis is one of the main pathogens that cause urinary tract infections. Therefore, the aim of this study was to analyze and compare the genetic profile of 36 clinical isolates of P. mirabilis that carry and do not carry the blaKPC and blaNDM gene with respect to virulence factors (mrpG, pmfA, ucaA, nrpG and pbtA) and antimicrobial resistance (blaVIM,blaIMP, blaSPM, blaGES,blaOXA-23-like, blaOXA-48-like, blaOXA-58-like and blaOXA-10-like). METHODS: The virulence and resistance genes were investigated by using PCR and sequencing. RESULTS: ERIC-PCR typing showed that the isolates showed multiclonal dissemination and high genetic variability. The gene that was most found blaOXA-10-like (n = 18), followed by blaKPC (n = 10) and blaNDM (n = 8). To our knowledge, this is the first report of blaOXA-10 in P. mirabilis in Brazil, as well as the first report of the occurrence of P. mirabilis co-carrying blaOXA-10/blaKPC and blaOXA-10/blaNDM. The blaNDM or blaKPC carrier isolates showed important virulence genes, such as ucaA (n = 8/44.4%), pbtA (n = 10/55.5%) and nrpG (n = 2/11.1%). However, in general, the non-carrier isolates of blaKPC and blaNDM showed a greater number of virulence genes when compared to the carrier group. CONCLUSION: Clinical isolates of P. mirabilis, in addition to being multi-drug resistant, presented efficient virulence factors that can establish infection outside the gastrointestinal tract.
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Proteus mirabilis , Factores de Virulencia , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Brasil , Humanos , Pruebas de Sensibilidad Microbiana , Proteus mirabilis/genética , Factores de Virulencia/genética , beta-Lactamasas/genéticaRESUMEN
The aim of this study was to characterize the ultrastructural effects caused by ß-lactam antibiotics in Klebsiella pneumoniae isolates. Three K. pneumoniae clinical isolates were selected for the study with resistance profiles for third-generation cephalosporins, aztreonam, and/or imipenem and with different resistance genes for extended-spectrum ß-lactamases (ESBL) or Klebsiella pneumoniae carbapenemase (KPC). Two K. pneumoniae isolates obtained from the microbiota, which were both resistant to amoxicillin and ampicillin, were also analyzed. In accordance with the susceptibility profile, the clinical isolates were subjected to subminimum inhibitory concentrations (sub-MICs) of cefotaxime, ceftazidime, aztreonam, and imipenem and the isolates from the microbiota to ampicillin and amoxicillin, for analysis by means of scanning and transmission electron microscopy. The K. pneumoniae isolates showed different morphological and ultrastructural changes after subjection to ß-lactams tested at different concentrations, such as cell filamentation, loss of cytoplasmic material, and deformation of dividing septa. Our results demonstrate that K. pneumoniae isolates harboring different genes that encode for ß-lactamases show cell alterations when subjected to different ß-lactam antibiotics, thus suggesting that they possess residual activity in vitro, despite the phenotypic resistance presented in the isolates analyzed.
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Antibacterianos/farmacología , Genes Bacterianos , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/ultraestructura , Microbiota/efectos de los fármacos , beta-Lactamasas/genética , beta-Lactamas/farmacología , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , Pruebas de Sensibilidad Microbiana , Análisis de Secuencia de ADNRESUMEN
This study aimed to co-encapsulate ceftazidime and tobramycin in zein nanoparticles coated with chitosan and to characterize and evaluate the antibacterial and antibiofilm activity against antibiotic-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae. Zein nanoparticles, synthesized using the nanoprecipitation method, were characterized by their particle size (Ø), polydispersity index (PDI), zeta potential (ζ), pH, and encapsulation efficiency (%EE). The chitosan coating provided stability, and physicochemical analyses revealed chemical interactions, efficient drug encapsulation, and thermal stability. The release kinetics demonstrated controlled release in simulated gastric and intestinal pH. The antibacterial activity, assessed by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), indicated effectiveness against both pathogens. Antibiofilm assays, conducted using the crystal violet method, demonstrated the inhibition and eradication of biofilms. The chitosan-coated zein nanoparticles with CAZ and/or TOB exhibited Ø (315-335 nm), PDI (<0.2), ζ (+40 to +50 mV), pH (5), and %EE (>55%). Notably, the co-encapsulation formulation (CAZ-TOB-ZNP-CH) showed enhanced antibacterial and antibiofilm activities compared to the individual formulations. These findings suggest that the developed nanoparticles present a promising alternative for treating respiratory and intestinal infections caused by antibiotic-resistant and biofilm-producing P. aeruginosa and K. pneumoniae.
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Proteus mirabilis is one of the main pathogens causing urinary tract infections and sepsis. To our knowledge, this is the first report of a P. mirabilis hosting bla GES. The presence of these genes was determined using PCR and sequencing. We identified the presence of bla GES-1 in all three isolates. In addition, we identified the bla KPC-2 and bla NDM-1 genes in the two strains. These data emphasize the importance of monitoring and surveillance of all enterobacteria. The circulation of P. mirabilis strains carrying bla GES-1 constitutes a new scenario of resistance in this species and should be an epidemiological alert for global health.
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Proteus mirabilis , beta-Lactamasas , Antibacterianos , Enterobacteriaceae , Pruebas de Sensibilidad Microbiana , Proteus mirabilis/genética , beta-Lactamasas/genéticaRESUMEN
OBJECTIVES: Multidrug-resistant Klebsiella pneumoniae carrying blaNDM-1 and blaKPC-2 genes are a worldwide concern for which combination antimicrobial therapy may be the only viable option. The aim of this study was to investigate the in vitro activity of combinations of polymyxin B (PMB) with meropenem (MEM), amikacin (AMK) and gentamicin (GEN) at subinhibitory concentrations against two K. pneumoniae clinical isolates co-harbouring blaNDM-1, blaKPC-2 and aminoglycoside-modifying enzymes and resistant to PMB. METHODS: Synergy and bactericidal activity were evaluated by chequerboard and time-kill assays against two PMB-resistantK. pneumoniae clinical isolates carrying the blaNDM-1, blaKPC-2, aac(3)-IIa, aac(6')-Ib, aph(3')-VI and ant(2'')-Ia genes. Five combinations of PMB, MEM, AMK and GEN were evaluated. RESULTS: The PMB/MEM and PMB/AMK combinations proved to be the best options against isolate K7R2, mainly because they demonstrated bactericidal activity when using subinhibitory concentrations of these antimicrobials. However, none of the studied combinations was bactericidal against isolate K11R2. CONCLUSION: The combinations used in this study showed synergy against NDM-and KPC-producing isolates but, given their bactericidal activity, the combinations of PMB/MEM and PMB/AMK were the most active against one isolate. It can also be concluded that the antimicrobials to which the bacteria were resistant could form part of combination therapy.
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Klebsiella pneumoniae , Polimixina B , Amicacina/farmacología , Aminoglicósidos , Gentamicinas , Klebsiella pneumoniae/genética , Meropenem/farmacología , Pruebas de Sensibilidad Microbiana , Polimixina B/farmacología , beta-LactamasasRESUMEN
INTRODUCTION: This study investigated the genetic environment of bla KPC-2 in Klebsiella pnemoniae multi-drug resistant clinical isolates. METHODS: Four carbapenemase gene isolates resistant to carbapenems, collected from infected patients from two hospitals in Brazil, were investigated using polymerase chain reaction and plasmid DNA sequencing. RESULTS: The bla KPC-2 gene was located between ISKpn6 and a resolvase tnpR in the non-Tn4401 element (NTEKPC-IId). It was detected on a plasmid belonging to the IncQ1 group. CONCLUSIONS: To our knowledge, this is the first report of the presence of the bla KPC-2 gene in the NTEKPC-IId element carried by plasmid IncQ1 from infections in Brazil.
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Antibacterianos/farmacología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , ADN Bacteriano/genética , Farmacorresistencia Bacteriana Múltiple , Humanos , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Plásmidos/genética , Reacción en Cadena de la PolimerasaRESUMEN
INTRODUCTION: The emergence of New Delhi metallo-ß-lactamase (NDM) is concernig because it reduces the antibiotic therapy options for bacterial infections. METHODS: Resistant and virulent genes from an isolate of Klebsiella pneumoniae derived from a patient with sepsis in a hospital in Recife-PE, Brazil, were investigated using PCR and DNA sequencing. RESULTS: bla NDM-1, aac(6')-Ib-cr and acrB resistance genes, and cps and mrkD virulence genes were detected. CONCLUSIONS: To our knowledge, this is the first report on bla NDM-1 in Recife-PE. This detection alerts researchers to the need to control the spread of bla NDM-1 resistance gene by this bacterium in Brazil.
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Antibacterianos/farmacología , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana Múltiple/genética , Klebsiella pneumoniae/genética , Virulencia/genética , beta-Lactamasas/genética , Femenino , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimología , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Sepsis/microbiología , Análisis de Secuencia de ADNRESUMEN
INTRODUCTION: The relationships between phagocytosis, and mucoid phenotype, plasmid profile and virulence, and resistance genetic characteristics of Klebsiella pneumoniae clinical isolates were evaluated. METHODS: Thirty isolates were used to determine the mucoid aspect. Four were selected for analysis of phagocytosis by alveolar macrophages. RESULTS: Thirty percent of the samples presented the mucoid phenotype. The phagocytosis rate ranged from 21.5% to 43.43%. Phagocytosis was not correlated with the plasmid profile, but was apparently correlated with mucoid phenotype and antibiotic susceptibility. CONCLUSIONS: Several virulence factors act in parallel in K. pneumoniae to impair host defense.
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Antibacterianos/farmacología , Farmacorresistencia Microbiana/genética , Klebsiella pneumoniae/genética , Fagocitosis/genética , Factores de Virulencia/genética , Virulencia/genética , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/patogenicidad , Fagocitosis/fisiología , Fenotipo , PlásmidosRESUMEN
This work aimed to investigate the chemical composition, antimicrobial, antinociceptive, acute toxicity and antioxidant activity of the essential oil of Algrizea minor (EOAm). The essential oil presented as the major constituents ß-Pinene (56.99%), α-Pinene (16.57%), Germacrene D (4.67%), Bicyclogermacrene (4.66%), (E)-Caryophyllene (3.76%) and Limonene (1.71%). It was verified that the essential oil did not show acute toxicity in the maximum dose of 5,000 mg/kg. In the evaluation of the antinociceptive activity it was verified that the essential oil reduced in 65.84% the number of writhing in the mice, reducing the pain in 59.17%, and the mechanism of action in pain reduction was opioid, similar to morphine. The essential oil also presented significant antimicrobial against Gram positive and Gram-negative bacteria and fungi, and the antioxidant activity was relevant. Therefore, these results demonstrate the great potential for the future development of pharmaceutical products with the essential oil of Algrizea minor (EOAm).
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INTRODUCTION: Pseudomonas aeruginosa, an important pathogen globally, presents several resistance mechanisms. This study aimed to investigate the presence of bla GES in clinical isolates of Pseudomonas aeruginosa obtained from various clinical specimens from patients admitted to three different hospitals in Recife, Brazil. The Guiana extended spectrum beta-lactamase (GES) enzymes are responsible for conferring broad spectrum resistance to beta-lactam drugs, including the carbapenems. METHODS: A total of 100 carbapenem-resistant P. aeruginosa isolates underwent polymerase chain reaction (PCR) testing to identify bla GES, bla KPC, bla SPM-1, bla IMP, and bla VIM. Additionally, PCR products positive for bla GES were sequenced. The clonal profiles of these same isolates were then determined by means of enterobacterial repetitive intergenic consensus (ERIC)-PCR analysis. RESULTS: PCR analysis revealed that four isolates harbored bla GES; DNA sequencing showed that two harbored bla GES-1 and two bla GES-11. Beta-lactamase genes bla SPM-1, bla IMP, bla VIM, and bla KPC were investigated; none of these genes was detected. Automated susceptibility testing methods (Vitek®2, bioMérieux) showed that the bla GES-1-positive isolates were only susceptible to polymyxin B. The patterns obtained with ERIC-PCR methods showed clonal relationship between the two isolates that harbored bla GES-11, whereas different clonal profiles were found in the isolates harboring bla GES-1. CONCLUSIONS: We detected the presence of bacterial isolates positive for two different variants of the enzyme GES in three different hospitals from Recife, Brazil. These enzymes have a great capacity for dissemination among Gram-negative bacteria and confer broad-spectrum resistance to beta-lactam antibiotics and to the carbapenems.
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Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Pseudomonas aeruginosa/genética , beta-Lactamasas/genética , Secuencia de Bases , Brasil , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Humanos , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/enzimología , Análisis de Secuencia de ADN , beta-Lactamasas/efectos de los fármacosRESUMEN
Abstract Proteus mirabilis is one of the main pathogens causing urinary tract infections and sepsis. To our knowledge, this is the first report of a P. mirabilis hosting bla GES. The presence of these genes was determined using PCR and sequencing. We identified the presence of bla GES-1 in all three isolates. In addition, we identified the bla KPC-2 and bla NDM-1 genes in the two strains. These data emphasize the importance of monitoring and surveillance of all enterobacteria. The circulation of P. mirabilis strains carrying bla GES-1 constitutes a new scenario of resistance in this species and should be an epidemiological alert for global health.
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Proteus mirabilis/genética , beta-Lactamasas/genética , Pruebas de Sensibilidad Microbiana , Enterobacteriaceae , AntibacterianosRESUMEN
INTRODUCTION: There is a mechanism of macrolide resistance in Staphylococcus spp. which also affects the lincosamides and type B streptogramins characterizing the so-called MLSB resistance, whose expression can be constitutive (cMLSB) or inducible (iMLSB) and is encoded mainly by ermA and ermC genes. The cMLSB resistance is easily detected by susceptibility testing used in the laboratory routine, but iMLSB resistance is not. Therapy with clindamycin in cases of infection with isolated iMLSB resistance may fail. OBJECTIVE: To characterize the phenotypic (occurrence of cMLSB and iMLSB phenotypes) and molecular (occurrence of ermA and ermC genes) profiles of MLSB resistance of clinical isolates of susceptible and methicillin-resistant Staphylococcus aureus and CNS (coagulase-negative Staphylococcus) from patients of a university hospital, in Pernambuco. METHODS: The antimicrobial susceptibility of 103 isolates was determined by the disk diffusion technique in Mueller-Hinton agar followed by oxacillin screening. The iMLSB phenotype was detected by D test. Isolates with cMLSB and iMLSB phenotypes were subjected to polymerase chain reaction (PCR) for the detection of ermA and ermC genes. RESULTS: The cMLSB and iMLSB phenotypes were respectively identified in 39 (37.9%) and five (4.9%) isolates. The iMLSB phenotype was found only in four (10.8%) methicillin-susceptible S. aureus and one (4.5%) methicillin-resistant S. aureus. In the 44 isolates subjected to PCR, four (9.1%) only ermA gene was detected, a lower frequency when compared to only ermC 17 (38.6%) gene and to one (2.3%) isolate presenting both genes. CONCLUSION: In the Staphylococcus spp. analyzed, the ermC gene was found more often than the ermA, although the iMLSB phenotype had been less frequent than the cMLSB. It was important to perform the D test for its detection to guide therapeutic approaches.
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Farmacorresistencia Bacteriana Múltiple/genética , Lincosamidas/farmacología , Macrólidos/farmacología , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Estreptogramina B/farmacología , Brasil , Pruebas Antimicrobianas de Difusión por Disco , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Genes Bacterianos/genética , Hospitales Universitarios , Humanos , FenotipoRESUMEN
Abstract INTRODUCTION: This study investigated the genetic environment of bla KPC-2 in Klebsiella pnemoniae multi-drug resistant clinical isolates. METHODS: Four carbapenemase gene isolates resistant to carbapenems, collected from infected patients from two hospitals in Brazil, were investigated using polymerase chain reaction and plasmid DNA sequencing. RESULTS: The bla KPC-2 gene was located between ISKpn6 and a resolvase tnpR in the non-Tn4401 element (NTEKPC-IId). It was detected on a plasmid belonging to the IncQ1 group. CONCLUSIONS To our knowledge, this is the first report of the presence of the bla KPC-2 gene in the NTEKPC-IId element carried by plasmid IncQ1 from infections in Brazil.
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Humanos , beta-Lactamasas/genética , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , Antibacterianos/farmacología , Plásmidos/genética , ADN Bacteriano/genética , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Farmacorresistencia Bacteriana Múltiple , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/enzimologíaRESUMEN
Abstract INTRODUCTION: The emergence of New Delhi metallo-β-lactamase (NDM) is concernig because it reduces the antibiotic therapy options for bacterial infections. METHODS: Resistant and virulent genes from an isolate of Klebsiella pneumoniae derived from a patient with sepsis in a hospital in Recife-PE, Brazil, were investigated using PCR and DNA sequencing. RESULTS: bla NDM-1, aac(6')-Ib-cr and acrB resistance genes, and cps and mrkD virulence genes were detected. CONCLUSIONS To our knowledge, this is the first report on bla NDM-1 in Recife-PE. This detection alerts researchers to the need to control the spread of bla NDM-1 resistance gene by this bacterium in Brazil.
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Humanos , Femenino , Proteínas Bacterianas/genética , Virulencia/genética , beta-Lactamasas/genética , Farmacorresistencia Bacteriana Múltiple/genética , Klebsiella pneumoniae/genética , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN , Sepsis/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimologíaRESUMEN
Abstract INTRODUCTION The relationships between phagocytosis, and mucoid phenotype, plasmid profile and virulence, and resistance genetic characteristics of Klebsiella pneumoniae clinical isolates were evaluated. METHODS Thirty isolates were used to determine the mucoid aspect. Four were selected for analysis of phagocytosis by alveolar macrophages. RESULTS Thirty percent of the samples presented the mucoid phenotype. The phagocytosis rate ranged from 21.5% to 43.43%. Phagocytosis was not correlated with the plasmid profile, but was apparently correlated with mucoid phenotype and antibiotic susceptibility. CONCLUSIONS: Several virulence factors act in parallel in K. pneumoniae to impair host defense.
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Humanos , Fagocitosis/genética , Virulencia/genética , Farmacorresistencia Microbiana/genética , Factores de Virulencia/genética , Klebsiella pneumoniae/genética , Antibacterianos/farmacología , Fagocitosis/fisiología , Fenotipo , Plásmidos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/patogenicidadRESUMEN
Abstract INTRODUCTION: Pseudomonas aeruginosa, an important pathogen globally, presents several resistance mechanisms. This study aimed to investigate the presence of bla GES in clinical isolates of Pseudomonas aeruginosa obtained from various clinical specimens from patients admitted to three different hospitals in Recife, Brazil. The Guiana extended spectrum beta-lactamase (GES) enzymes are responsible for conferring broad spectrum resistance to beta-lactam drugs, including the carbapenems. METHODS: A total of 100 carbapenem-resistant P. aeruginosa isolates underwent polymerase chain reaction (PCR) testing to identify bla GES, bla KPC, bla SPM-1, bla IMP, and bla VIM. Additionally, PCR products positive for bla GES were sequenced. The clonal profiles of these same isolates were then determined by means of enterobacterial repetitive intergenic consensus (ERIC)-PCR analysis. RESULTS: PCR analysis revealed that four isolates harbored bla GES; DNA sequencing showed that two harbored bla GES-1 and two bla GES-11. Beta-lactamase genes bla SPM-1, bla IMP, bla VIM, and bla KPC were investigated; none of these genes was detected. Automated susceptibility testing methods (Vitek®2, bioMérieux) showed that the bla GES-1-positive isolates were only susceptible to polymyxin B. The patterns obtained with ERIC-PCR methods showed clonal relationship between the two isolates that harbored bla GES-11, whereas different clonal profiles were found in the isolates harboring bla GES-1. CONCLUSIONS: We detected the presence of bacterial isolates positive for two different variants of the enzyme GES in three different hospitals from Recife, Brazil. These enzymes have a great capacity for dissemination among Gram-negative bacteria and confer broad-spectrum resistance to beta-lactam antibiotics and to the carbapenems.