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1.
Pan Afr Med J ; 33: 146, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31558943

RESUMO

Introduction: Infection due to multidrug-resistant microorganisms is a growing threat in healthcare settings. Acinetobacter species specifically A. baumannii is increasingly becoming resistant to most antimicrobial agents recommended for treatment. This study aimed to determine the antimicrobial susceptibility pattern of Acinetobacter species isolated from patients in Kenyatta National Hospital. Methods: We conducted a retrospective study based on VITEK 2 (BioMérieux) electronic records capturing identification and antimicrobial susceptibility of Acinetobacter isolates from patient samples analyzed between 2013 and 2015 at Kenyatta National Hospital microbiology laboratory. Generated data were analyzed using WHONET and SPSS. Results: A total of 590 Acinetobacter isolates were analyzed. 85% of the isolates tested were multi-drug resistant (MDR). Among the 590 isolates, 273 (46%) were from tracheal aspirates and 285 (48%) from the critical care unit. A. baumannii was the most frequently isolated species with high susceptibility to amikacin (77%) and poor susceptibility to ciprofloxacin (69-76%), tobramycin (37%) and meropenem (27%). Both A. lwoffii and A. haemolyticus had high susceptibility to amikacin (80-100%) and meropenem (75-100%). Conclusion: A. baumannii is resistant to commonly administered antibiotics. There is need for continuous antimicrobial resistance surveillance especially in health care facilities and strengthening of antibiotic stewardship programmes which will contribute to enhancement of infection control policies.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter/efeitos dos fármacos , Antibacterianos/farmacologia , Acinetobacter/isolamento & purificação , Infecções por Acinetobacter/epidemiologia , Infecções por Acinetobacter/microbiologia , Farmacorresistência Bacteriana Múltipla , Feminino , Hospitais , Humanos , Quênia , Masculino , Testes de Sensibilidade Microbiana , Estudos Retrospectivos
2.
APMIS ; 127(12): 753-763, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31512768

RESUMO

Iron uptake system is expressed in early stages of Acinetobacter baumannii infections under iron-restricted conditions. This study is aimed at the evaluation of immuno-protectivity of BfnH in comparison with BauA in both mature and selected fragmental proteins. The study was designed in single and combined forms of antigens. BfnH is presented in 3472 strains of A. baumannii with more than 97% identity. The preliminary immune-informatics analysis of this protein indicated a region from the ß-barrel domain including exposed loops 2-5, with antigenic score comparable to that of BfnH. There was a significant rise in the specific IgG response in all test groups. The bacterial challenge with a lethal dose of A. baumannii demonstrated partial protection of whole proteins which coincides with a significant reduction in the bacterial population colonized in the main organs and an increase in the survival level. Passive immunization of the mice brought about 50% survival in the mice groups immunized with BfnH and with a combination of BfnH and BauA. The protectivity of siderophore receptors suggests their potential immunogenic role that could be considered as a component of multivalent subunit vaccine candidates against A. baumannii.


Assuntos
Infecções por Acinetobacter/prevenção & controle , Acinetobacter baumannii/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Imunização , Receptores de Superfície Celular/imunologia , Infecções por Acinetobacter/imunologia , Infecções por Acinetobacter/microbiologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Carga Bacteriana , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/imunologia , Epitopos de Linfócito B , Feminino , Imunogenicidade da Vacina , Camundongos Endogâmicos BALB C , Receptores de Superfície Celular/química , Receptores de Superfície Celular/genética
3.
Rev Soc Bras Med Trop ; 52: e20190237, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31508785

RESUMO

INTRODUCTION: The increased use of colistin against infections caused by Acinetobacter baumannii and Pseudomonas aeruginosa has resulted in colistin resistance. The purpose of this study was to detect plasmid-mediated mcr-1 gene in colistin-resistant A. baumannii and P. aeruginosa isolates. METHODS: A total of 146 clinical isolates of A. baumannii (n = 62) and P. aeruginosa (n = 84) were collected from the four largest tertiary care hospitals in Peshawar, Pakistan. All bacterial isolates were phenotypically screened for multidrug resistance using the Kirby-Baur disc diffusion method. The minimum inhibitory concentration (MIC) of colistin in all isolates was phenotypically performed using dilution methods. mcr-1 gene was detected through polymerase chain reaction and the nucleotide sequence of amplicon was determined using Sanger sequencing. RESULTS: Approximately 96.7% A. baumannii and 83.3% P. aeruginosa isolates were resistant to multiple antibiotics. Colistin resistance was found in 9.6% (6/62) of A. baumannii and 11.9% (10/84) of P. aeruginosa isolates. Among 16 colistin resistant isolates, the mcr-1 gene was detected in one A. baumannii (1.61% of total isolates; 16.6% of colistin resistant isolates) and one P. aeruginosa strain (1.19% of total isolates; 10% of colistin resistant isolates). Nucleotide BLAST showed 98-99% sequence similarity to sequences of the mcr-1 gene in GenBank. CONCLUSIONS: Our study reports, for the first time, the emergence of plasmid-mediated mcr-1-encoded colistin resistance in multidrug resistant strains of A. baumannii and P. aeruginosa. Further large scales studies are recommended to investigate the prevalence of this mode of resistance in these highly pathogenic bacteria.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Acinetobacter baumannii/efeitos dos fármacos , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana , Paquistão , Plasmídeos/genética , Pseudomonas aeruginosa/efeitos dos fármacos
4.
Rev Soc Bras Med Trop ; 52: e20190243, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31508786

RESUMO

INTRODUCTION: In recent decades, the prevalence of carbapenem-resistant Acinetobacter isolates has increased, and the production of oxacillinase (OXA)-type carbapenemases is the main mechanism underlying resistance. We evaluated OXA production from 114 Acinetobacter isolates collected between March and December 2013 from different clinical specimens of patients in two hospitals (Hospital 1 [n = 61] and Hospital 2 [n = 53]) located in Niterói, Rio de Janeiro, Brazil. We also evaluated the genetic diversity of OXA-producing isolates. METHODS: All the isolates were identified through the automated system Vitek II and matrix-assisted laser desorption ionization-time of flight mass spectrometry MALDI-TOF MS as belonging to the A. baumannii-A. calcoaceticuscomplex. Antimicrobial susceptibility profiles were verified through agar diffusion tests. The presence of OXA-encoding genes was confirmed by PCR. The genetic diversity of isolates positive for carbapenemase production was analyzed through pulsed-field gel electrophoresis. RESULTS: There was a high rate of resistance to carbapenems in the isolates (imipenem: 96%; meropenem: 92%) from both hospitals. Moreover, a high percentage (95.6%) of OXA-23-positive isolates was observed for both hospitals, indicating that this was the main mechanism of carbapenem-resistance among the studied population. In addition, most isolates (96.5%) were positive for bla OXA-51. A high genetic diversity and a few major genotypes were found among the OXA-23-positive isolates analyzed. Only intra-hospital dissemination was observed. CONCLUSIONS: The elevated dissemination of bla OXA-23-like observed among Acinetobacter isolates from both the studied hospitals highlights the need for continuous epidemiological surveillance in these institutions.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter/enzimologia , beta-Lactamases/biossíntese , Acinetobacter/efeitos dos fármacos , Acinetobacter/genética , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , Brasil , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Hospitais Gerais , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , beta-Lactamases/efeitos dos fármacos
5.
BMC Infect Dis ; 19(1): 742, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31443635

RESUMO

BACKGROUND: Trends in antimicrobial resistance help inform infection control efforts. We examined trends in resistance for Enterobacteriaceae and Acinetobacter spp. from 2013 to 2017 in hospitalized US patients. METHODS: We analyzed antimicrobial susceptibility of non-duplicate isolates in hospitalized patients (not limited to hospital-acquired infections) in the US BD Insights Research Database. Resistance profiles of interest were extended-spectrum beta-lactamase (ESBL)-producing, multidrug resistant (MDR), and carbapenem-nonsusceptible (Carb-NS) phenotypes of Enterobacteriaceae, and MDR and Carb-NS Acinetobacter spp. Time series models were used to evaluate the patterns of resistance trends in rate per 100 hospital admissions and proportion per isolates tested. RESULTS: More than 1 million Enterobacteriaceae isolates were obtained from 411 hospitals; 12.05% were ESBL, 1.21% Carb-NS, and 7.08% MDR. Urine was the most common source. For Acinetobacter spp. (n = 19,325), 37.48% were Carb-NS, 47.66% were MDR, and the most common source was skin/wound cultures. Trend analyses showed that the rates of ESBL and Carb-NS Enterobacteriaceae per 100 hospital admissions increased significantly between 2013 and 2017. Rates of MDR Enterobacteriaceae and Carb-NS and MDR Acinetobacter spp. decreased during this time period. Trends in proportions of resistant isolates generally mirrored trends in rates per 100 hospital admissions. MDR Enterobacteriaceae and Carb-NS and MDR Acinetobacter spp. were more common in winter than summer. CONCLUSIONS: In this large-scale study of patients in US hospitals, rates of ESBL and Carb-NS Enterobacteriaceae per 100 hospital admissions increased between 2013 and 2017. MDR Enterobacteriaceae and MDR and Carb-NS Acinetobacter spp. isolates decreased over this period. These data support continuing infection control and stewardship efforts and the development of new therapeutic options.


Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Infecções por Enterobacteriaceae/epidemiologia , Enterobacteriaceae/efeitos dos fármacos , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Infecções por Acinetobacter/microbiologia , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Infecções por Enterobacteriaceae/microbiologia , Hospitais/estatística & dados numéricos , Humanos , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Estados Unidos/epidemiologia , beta-Lactamases/metabolismo
6.
J Microbiol Immunol Infect ; 52(4): 654-662, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31446929

RESUMO

BACKGROUND/PURPOSE: Diabetes is associated with increased mortality in Acinetobacter baumannii (AB) complex infection. This study investigated the risk factors and relationship of diabetic status and glycemic indices to mortality in patients with carbapenem-resistant (CR) AB complex bacteremia. METHODS: Relationship of glycemic indices to mortality were compared in adult diabetes (DM) and nondiabetes (non-DM) patients with CRAB complex bacteremia hospitalized from January 2010 to December 2015 in MacKay Memorial Hospital, Taiwan. RESULTS: Of 317 patients with CRAB complex bacteremia, 146 (46.06%) had diabetes. DM patients were elderly (mean age of 69.23 years) and the mortality rate was higher (64.38% vs. 52.05%, p = 0.036) than in non-DM patients. By multivariate analysis, septic shock was associated with increased mortality in DM patients. Hypoglycemia was associated with increased mortality in non-DM patients only (100% vs. 50.33%, p = 0.006). The lowest mortality was for the blood glucose range 70-100 mg/dL in non-DM patients (43.24%) and 100-140 mg/dL for DM patients (56.52%). Increased glycemic variability (coefficient of variation (CV) > 40% compared to < 20%) was associated with increased mortality in non-DM patients (86.36% vs. 47.12%, p = 0.003). CONCLUSION: Effects of dysglycemia on mortality due to CRAB complex bacteremia differ according to diabetic status. Mortality was higher in DM patients. In non-DM patients, hypoglycemia and increased CV were associated with increased mortality. The lowest mortality was for the blood glucose range 70-100 mg/dL in non-DM patients and 100-140 mg/dL for DM patients.


Assuntos
Infecções por Acinetobacter/mortalidade , Bacteriemia/mortalidade , Glicemia/análise , Carbapenêmicos/farmacologia , Complicações do Diabetes/microbiologia , Complicações do Diabetes/mortalidade , Farmacorresistência Bacteriana , Infecções por Acinetobacter/sangue , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Bacteriemia/sangue , Bacteriemia/microbiologia , Complicações do Diabetes/sangue , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Taiwan/epidemiologia
7.
Ann Clin Microbiol Antimicrob ; 18(1): 19, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31266519

RESUMO

BACKGROUND: Multidrug-resistant (MDR) Acinetobacter baumannii infections are considered as emerging nosocomial infections particularly in patients hospitalized in intensive care units (ICUs). Therefore, reliable detection of MDR strains is crucial for management of treatment but also for epidemiological data collections. The purpose of this study was to compare antimicrobial resistance and the clonal distribution of MDR clinical and environmental A. baumannii isolates obtained from the ICUs of 10 different hospitals from five geographical regions of Turkey in the context of the demographic and clinical characteristics of the patients. METHODS: A multicenter-prospective study was conducted in 10 medical centers of Turkey over a 6 month period. A total of 164 clinical and 12 environmental MDR A. baumannii isolates were included in the study. Antimicrobial susceptibility testing was performed for amikacin (AN), ampicillin-sulbactam (SAM), ceftazidime (CAZ), ciprofloxacin (CIP), imipenem (IMP) and colistin (COL) by microdilution method and by antibiotic gradient test for tigecycline (TIG). Pulsed-field gel electrophoresis (PFGE) was performed to determine the clonal relationship between the isolates. The detection of the resistance genes, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, blaIMP, blaNDM, blaKPC, blaOXA-48 and blaPER-1 was carried out using the PCR method. RESULTS: The mortality rate of the 164 patients was 58.5%. The risk factors for mortality included diabetes mellitus, liv1er failure, the use of chemotherapy and previous use of quinolones. Antimicrobial resistance rates for AN, SAM, CAZ, CIP, IMP, COL and TIG were 91.8%, 99.4%, 99.4%, 100%, 99.4%, 1.2% and 1.7% respectively. Colistin showed the highest susceptibility rate. Four isolates did not grow on the culture and were excluded from the analyses. Of 172 isolates, 166 (96.5%) carried blaOXA-23, 5 (2.9%) blaOXA-58 and one isolate (0.6%) was positive for both genes. The frequency of blaPER-1 was found to be 2.9%. None of the isolates had blaIMP, blaKPC, blaNDM and blaOXA-48 genes. PFGE analysis showed 88 pulsotypes. Fifteen isolates were clonally unrelated. One hundred fifty-seven (91.2%) of the isolates were involved in 14 different clusters. CONCLUSIONS: Colistin is still the most effective antibiotic for A. baumannii infections. The gene blaOXA-23 has become the most prevalent carbapenemase in Turkey. The distribution of invasive A. baumannii isolates from different regions of Turkey is not diverse so, infection control measures at medical centers should be revised to decrease the MDR A. baumannii infections across the country. The results of this study are expected to provide an important baseline to assess the future prophylactic and therapeutic options.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/isolamento & purificação , Adulto , Idoso , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Colistina/farmacologia , Infecção Hospitalar/epidemiologia , Feminino , Humanos , Imipenem/farmacologia , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Epidemiologia Molecular , Filogenia , Estudos Prospectivos , Turquia/epidemiologia , beta-Lactamases/genética , beta-Lactamases/metabolismo
8.
Rev Soc Bras Med Trop ; 52: e20180348, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31271614

RESUMO

We report the occurrence in Brazil of the bla NDM-1 gene in Acinetobacter pittii, prior to the previously described first reports regarding the species Providencia rettgeri and Enterobacter hormaechei. Clinical isolates were investigated by polymerase chain reaction followed by bidirectional sequencing, and species was confirmed by 16S rDNA sequencing and matrix-assisted laser desorption-ionization time-of-flight spectrometry. A. pittii carrying bla NDM-1 was confirmed in a patient with no national or international travel history, or transfer from another hospital. The findings warn of the possibility of silent spread of bla NDM-1 to the community.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter/isolamento & purificação , Antibacterianos/uso terapêutico , beta-Lactamases/isolamento & purificação , Infecções por Acinetobacter/tratamento farmacológico , Idoso de 80 Anos ou mais , Brasil , Feminino , Humanos , Testes de Sensibilidade Microbiana , beta-Lactamases/genética
9.
BMC Infect Dis ; 19(1): 629, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31315572

RESUMO

BACKGROUND: Nosocomial infections and persistence of multidrug resistant biofilm forming Acinetobacter baumannii in hospitals has made it as a serious problem in healthcare settings worldwide. METHODS: A total of 100 A. baumannii clinical isolates from immunocompromised patients hospitalized in ICU were investigated for biofilm formation, the presence of biofilm related genes (bap, ompA, csuE, fimH, epsA, blaPER-1, bfmS, ptk, pgaB, csgA, kpsMII), integron characterization and molecular typing based on REP-PCR. RESULTS: All isolates were resistant to three or more categories of antibiotics and considered as multidrug resistant (MDR). A total of 32 isolates were resistant to all tested antibiotics and 91% were extensively drug-resistance (XDR). All isolates were able to produce biofilm and 58% of isolates showed strong ability to biofilm formation. All strong biofilm forming A. baumannii isolates were XDR. All A. baumannii isolates carried at least one biofilm related gene. The most prevalent gene was csuE (100%), followed by pgaB (98%), epsA and ptk (95%), bfmS (92%) and ompA (81%). 98% of isolates carried more than 4 biofilm related genes, simultaneously. Class I integron (67%) was more frequent in comparison with class II (10%) (P < 0.05). The REP-PCR patterns were classified as 8 types (A-H) and 21 subtypes. The A1 (23%) and C1 (15%) clusters were the most prevalent among A. baumannii isolates (P < 0.05). According to the REP-PCR patterns, 23% of all isolates had a clonal relatedness. CONCLUSION: Our study revealed the high frequency of biofilm forming XDR A. baumannii in ICU patients, with a high prevalence of biofilm related genes of csuE and pgaB. It seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of XDR A. baumannii in our country.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/patogenicidade , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Hospedeiro Imunocomprometido , Unidades de Terapia Intensiva , Irã (Geográfico) , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Virulência
10.
Int J Food Microbiol ; 305: 108248, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31226568

RESUMO

Species of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex are important human pathogens which can be recovered from animals and food, potential sources for their dissemination. The aim of the present study was to characterise the Acinetobacter isolates recovered from market meat samples in Peru. From July through August 2012, 138 meat samples from six traditional markets in Lima were cultured in Lysogeny and Selenite broths followed by screening of Gram-negative bacteria in selective media. Bacterial isolates were identified by MALDI-TOF MS and DNA-based methods and assessed for their clonal relatedness and antimicrobial susceptibility. Twelve Acinetobacter isolates were recovered from calf samples. All but one strain were identified as members of the clinically-relevant Acinetobacter calcoaceticus-Acinetobacter baumannii complex: 9 strains as Acinetobacter pittii, 1 strain as A. baumannii, and 1 strain as the recently described novel species A. dijkshoorniae. The remaining strain could not be identified at the species level unambiguously but all studies suggested close relatedness to A. bereziniae. All isolates were well susceptible to antibiotics. Based on macrorestriction analysis, six isolates were further selected and some of them were associated with novel MLST profiles. The presence of pathogenic Acinetobacter species in human consumption meat might pose a risk to public health as potential reservoirs for their further spread into the human population. Nevertheless, the Acinetobacter isolates from meat found in this study were not multidrug resistant and their prevalence was low. To our knowledge, this is also the first time that the A. dijkshoorniae species is reported in Peru.


Assuntos
Infecções por Acinetobacter/veterinária , Acinetobacter/isolamento & purificação , Doenças dos Bovinos/microbiologia , Carne/microbiologia , Acinetobacter/efeitos dos fármacos , Acinetobacter/genética , Acinetobacter/patogenicidade , Infecções por Acinetobacter/microbiologia , Animais , Antibacterianos/farmacologia , Bovinos , Contaminação de Alimentos/análise , Humanos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Peru
11.
Nat Commun ; 10(1): 2763, 2019 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-31235751

RESUMO

Multidrug resistant (MDR) Acinetobacter baumannii poses a growing threat to global health. Research on Acinetobacter pathogenesis has primarily focused on pneumonia and bloodstream infections, even though one in five A. baumannii strains are isolated from urinary sites. In this study, we highlight the role of A. baumannii as a uropathogen. We develop the first A. baumannii catheter-associated urinary tract infection (CAUTI) murine model using UPAB1, a recent MDR urinary isolate. UPAB1 carries the plasmid pAB5, a member of the family of large conjugative plasmids that represses the type VI secretion system (T6SS) in multiple Acinetobacter strains. pAB5 confers niche specificity, as its carriage improves UPAB1 survival in a CAUTI model and decreases virulence in a pneumonia model. Comparative proteomic and transcriptomic analyses show that pAB5 regulates the expression of multiple chromosomally-encoded virulence factors besides T6SS. Our results demonstrate that plasmids can impact bacterial infections by controlling the expression of chromosomal genes.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/patogenicidade , Infecções Relacionadas a Cateter/microbiologia , Plasmídeos/genética , Pneumonia Bacteriana/microbiologia , Infecções Urinárias/microbiologia , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Infecções Relacionadas a Cateter/epidemiologia , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla/genética , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Humanos , Camundongos , Pneumonia Bacteriana/epidemiologia , Proteômica , Estudos Retrospectivos , Sistemas de Secreção Tipo VI/genética , Sistemas de Secreção Tipo VI/metabolismo , Cateteres Urinários/efeitos adversos , Cateteres Urinários/microbiologia , Sistema Urinário/microbiologia , Infecções Urinárias/epidemiologia , Virulência/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
12.
J Med Microbiol ; 68(8): 1253-1265, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31215857

RESUMO

INTRODUCTION: Acinetobacter baumannii is one of the most important nosocomial pathogens, mainly due to its ability to accumulate antibiotic-resistances and to persist in the hospital environment - characteristics related to biofilm production. It is well-known that A. baumannii is inhibited by the proline-rich peptide Bac7(1-35), but its putative effects at sub-MICs were never considered. AIMS: We examined the sub-MIC effect of Bac7(1-35) on the growth rate, resistance induction and some A. baumannii features linked to virulence. METHODOLOGY: Growth kinetics in the presence of sub-MICs of Bac7(1-35) were evaluated spectrophotometrically. Peptide uptake was quantified by cytometric analysis. The ability of Bac7(1-35) to interfere with biofilm production was investigated by the crystal violet method and confocal microscopy. Bacterial motility was observed at the interphase between a layer of a semi-solid medium and the polystyrene bottom of a Petri dish. The induction of resistance was evaluated after serial passages with sub-MICs of the peptide. RESULTS: Although the MIC of Bac7(1-35) was between 2-4 µM for all tested strains, its effect on the growth rate at sub-MICs was strain-dependent and correlated with the amount of peptide internalized by each strain. Sub-MICs of Bac7(1-35) induced a strongly strain-dependent effect on biofilm formation and reduced motility in almost all strains, but interestingly the peptide did not induce resistance. CONCLUSION: Bac7(1-35) is internalized into A. baumannii and is able to inhibit biofilm formation and bacterial motility, without inducing resistance. This study stresses the importance of considering possible effects that antimicrobials could have at sub-MICs, mimicking a common condition during antibiotic treatment.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/patogenicidade , Acinetobacter baumannii/fisiologia , Antibacterianos/química , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/metabolismo , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana , Humanos , Locomoção/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Especificidade da Espécie , Virulência/efeitos dos fármacos
13.
Future Microbiol ; 14: 581-586, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31172805

RESUMO

Aim: To assess the effect of colistin-glycopeptide combination against a multidrug-resistant strain of Acinetobacter baumannii. Materials & methods: We used in vitro procedures (Etest method, checkerboard test and kill-time assays) and a mouse model of a carbapenem-resistant A. baumannii pneumonia. Results: The colistin-teicoplanin combination allowed a 74% increase of the survival in the mouse model within the 4 days following bacterial inoculation as compared with saline or colistin alone (p = 0.06). Concurrently, the colistin-vancomycin combination presented a similar efficacy as compared with saline or colistin alone in the mouse model. Conclusion: According to those preliminary results, using the colistin-teicoplanin combination in therapeutic deadlocks encountered in certain multiresistant A. baumannii pneumonia could be envisaged if the results are confirmed.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/efeitos dos fármacos , Colistina/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Glicopeptídeos/farmacologia , Pneumonia/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Animais , Antibacterianos/farmacologia , Modelos Animais de Doenças , Combinação de Medicamentos , Sinergismo Farmacológico , Feminino , Camundongos , Camundongos Endogâmicos C3H , Testes de Sensibilidade Microbiana , Taxa de Sobrevida , Teicoplanina/farmacologia , Vancomicina/farmacologia
14.
Braz J Microbiol ; 50(3): 695-696, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31134524

RESUMO

In Brazil, A. baumannii has been described as nosocomial pathogens causing hospital-acquired infections. Current WGS technologies have been useful in identifying of genetic features between Acinetobacter isolates. Here, we report the draft genome sequence of OXA-23 producing A. baumannii CCBH15815 clinical isolate, belonging to ST730/ST783, recovered from a 21-year-old hospitalised patient. We observed important resistance determinant genes, especially beta-lactamases-encoding genes, in an estimated genome size of 4,058,633 bp with 3839 predicted coding regions.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Proteínas de Bactérias/metabolismo , Infecção Hospitalar/microbiologia , beta-Lactamases/metabolismo , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Brasil , Tamanho do Genoma , Genoma Bacteriano , Humanos , Tipagem de Sequências Multilocus , Adulto Jovem , beta-Lactamases/genética
15.
Curr Microbiol ; 76(7): 842-847, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31053906

RESUMO

Diabetic foot ulcer infections are frequently polymicrobial in nature and exhibit increased morbidity and mortality, as well as, treatment failures. Interactions between Acinetobacter baumannii and Staphylococcus aureus were studied, which showed strain-dependent changes in growth and antibiotic susceptibility. This study examined the interactions between two clinical strains of A. baumannii (1929) and S. aureus (1928) that were recovered from skin and soft tissues of a diabetic patient. When S. aureus 1928 and A. baumannii 1929 were co-cultured together, there was no significant decrease in growth in either clinical strains, indicating that both strains can co-exist in the same site of infection. Additionally, neither strains experienced statistically significant changes in susceptibility. These findings highlight that these two pathogens can be found in the same niche of infection, which may lead to more aggressive outcome of the infection.


Assuntos
Infecções por Acinetobacter/microbiologia , Coinfecção/microbiologia , Pé Diabético/microbiologia , Interações Microbianas , Infecções dos Tecidos Moles/microbiologia , Infecções Estafilocócicas/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/fisiologia , Antibacterianos/farmacologia , Complicações do Diabetes/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/fisiologia
16.
BMC Infect Dis ; 19(1): 452, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31113374

RESUMO

BACKGROUND: To investigate the carbapenem resistance mechanisms and clonal relationship of carbapenem-resistant Acinetobacter baumannii (CRAB) strains isolated in the intensive care unit (ICU) of the First Affiliated Hospital of Jiamusi University, management approaches to ICU clonal CRAB outbreaks were described. METHODS: The sensitivity of the antibiotic was determined using the VITEK-2 automated system. Carbapenemase genes (blaTEM, blaSHV, blaKPC, blaNDM, blaIMP-4, blaVIM, blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58), AmpC enzyme genes (blaACC, blaDHA, blaADC), and ISAba1 were assessed for all collected isolates using polymerase chain reaction (PCR). The transfer of resistance genes was investigated via conjugation experiments. The clonal relationship of isolates was determined via enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus sequence typing (MLST). When the detection rate of CRAB increased from 25% in 2010 to 92% in 2014, a number of actions were initiated, including enhanced infection control, staff education, and the cleaning of the hospital environment. RESULTS: Clinical isolates were positive for the following genes: blaOXA23, blaOXA51, blaOXA24, blaADC, blaTEM, ISAba1, ISA-23, and ISA-ADC; however, blaOXA58, ISA-51, blaNDM, blaIMP, blaKPC, blaTEM, blaSHV, blaVIM, and blaACC were not detected. Four carbapenem-resistant isolates successfully transferred plasmids from A. baumannii isolates to E. coli J53. MLST showed that all strains belonged to ST2 except for one isolate, which belonged to the new genotype ST1199. The ERIC-PCR method found the following three genotypes: type A in 8, type B in 12, type C in 1, and two profiles (A, B) belonged to ST2. After taking control measures, the prevalence of CRAB isolates decreased, and the discovery rate of CRAB dropped to 11.4% in 2017. CONCLUSION: The obtained result suggests that blaOXA-23-producing CC2 isolates were prevalent in the ICU of the First Affiliated Hospital of Jiamusi University. Targeted surveillance was implemented to identify the current situation of the ICU and the further implementation of infection control effectively prevented the spread of nosocomial infection.


Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/efeitos dos fármacos , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , beta-Lactamases/genética , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/prevenção & controle , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Carbapenêmicos/farmacologia , China/epidemiologia , Infecção Hospitalar/prevenção & controle , Surtos de Doenças , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterobacteriaceae/genética , Feminino , Transferência Genética Horizontal , Humanos , Controle de Infecções/métodos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade
17.
J Med Microbiol ; 68(6): 860-865, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31050632

RESUMO

PURPOSE: Multi-drug resistant (MDR) Acinetobacter baumannii has introduced a worldwide health crisis. The purposes of this study were to characterize the clonal relatedness among MDR clinical strains and to introduce a new two-locus typing method confirmed by multi-locus sequence typing (MLST). METHODOLOGY: In this study, we determined antimicrobial resistance, detected genes associated with carbapenem resistance and characterized clonal relatedness among 99 clinical isolates extracted from 82 hospitalized inpatients in a university hospital. RESULTS: Of the 99 A. baumannii isolates, 92.9% (92/99) were resistant to imipenem and 97.9% (97/99) had an MDR profile. We found that the high prevalence of blaVIM [94.9% (94/99)] and blaOXA-23-like [93.93% (93/99)] is the main mechanism of carbapenem resistance. This study proposes a new two-locus typing (blaOXA-51-like and ampC) method for the rapid identification of clonal complexes (CCs). The results of this method and confirmation by MLST show that clinical isolates carry blaOXA-68 as well as ampC-10 or ampC-20 genes belonging to CC10 (ST10); blaOXA-66 and ampC-2 belonging to CC2 (ST2); and blaOXA-71 and ampC-3 belonging to CC3 (ST3). One isolate had blaOXA-90 with an undetermined allele number of ampC belonging to ST513. CONCLUSION: The high prevalence of MDR strains and the circulation of four limited clones, including ST10 (45/99), ST2 (41/99), ST3 (12/99) and ST513 (1/99), in the clinical setting highlights the importance of a rigorous infection control programme. The two-locus typing method has more discrimination than the application of each method separately and it could be applied for the rapid determination of the CC without performing MLST.


Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Imipenem/farmacologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Adulto , Idoso , Feminino , Hospitais de Ensino , Hospitais Universitários , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus
18.
Crit Rev Microbiol ; 45(3): 315-333, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31012772

RESUMO

Acinetobacter baumannii (AB) is one of the most notorious and opportunistic pathogens, which caused high morbidity and mortality rate and World Health Organization (WHO) declared this bacterium as priority-1 pathogen in 2017. The current antibacterial agents, such as colistins, carbapenems, and tigecyclines have limited applications, which necessitate novel and alternative therapeutic remedies. Thus, the understanding of recent perspectives on the virulent factors and antibiotic resistance mechanism exhibited by the bacteria are extremely important. In addition to many combinatorial therapies of antibacterial, there is several natural compounds demonstrated significant antibacterial potential towards these bacteria. The computational systems biology and high throughput screening approaches provide crucial insights in identifying novel drug targets and lead molecules with therapeutics potential. Hence, this review provides profound insight on the recent aspects of the virulent factors associated with AB, role of biofilm formation in drug resistance and the mechanisms of multidrug resistance. This review further illustrates the status of current therapeutic agents, scope, and applications of natural therapeutics, such as herbal medicines and role of computational biology, immunoinformatics and virtual screening in novel lead developments. Thus, this review provides novel insight on latest developments in drug-resistance mechanism of multidrug-resistant A. baumannii (MDRAB) and discovery of probable therapeutic interventions.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/metabolismo , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla , Fatores de Virulência/metabolismo , Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/genética , Animais , Antibacterianos/uso terapêutico , Proteínas de Bactérias/genética , Humanos , Fatores de Virulência/genética
19.
Int J Antimicrob Agents ; 53(6): 844-849, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30928684

RESUMO

In total, 95 Acinetobacter baumannii isolates recovered from patients from two hospitals in Cochabamba, Bolivia were studied. The presence of class D and B ß-lactamases was investigated using polymerase chain reaction, and antimicrobial susceptibility testing was performed by agar dilution and broth microdilution. The resistance rate to carbapenems was 53.7%. All carbapenem-resistant A. baumannii (CRAb, n=51) and four carbapenem-susceptible isolates were further analysed by whole-genome sequencing. The resulting genome assemblies were used to identify the acquired resistome, and core genome multi-locus sequence typing (cgMLST) was used to determine their molecular epidemiology. All but one of the CRAb isolates (n=50) belonged to international clone (IC) 7 and they clustered into five sequence types; on cgMLST, they were found to be separated by ≥40 alleles. All CRAb isolates carried blaOXA-23 on transposon Tn2008. Metallo-ß-lactamases were not detected. These data show that dissemination of several IC7 A. baumannii clones harbouring the carbapenem resistance determinant blaOXA-23 is occurring in these two hospitals in Cochambamba.


Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Doenças Endêmicas , Genoma Bacteriano , Genótipo , Tipagem de Sequências Multilocus , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Bolívia/epidemiologia , Análise por Conglomerados , Hospitais , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Reação em Cadeia da Polimerase , beta-Lactamases/genética
20.
Microb Pathog ; 131: 9-14, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30930220

RESUMO

Acinetobacter baumannii is considered as a major cause of nosocomial infection worldwide. Various vaccine formulations have been mostly studied based on secreted or surface-exposed proteins of A. baumannii in murine models. Serum resistance proteins are critical virulence factors in bloodstream infections. AbOmpA and PKF are two major factors involved in serum resistance and could be considered as promising vaccine targets. In this study IgG1, IgG2c, Total-IgG concentrations, survival rates and spleen bacterial loads were studied in C57/BL mice model according to PKF, AbOmpA and AbOmpA + PKF vaccine formulations. The findings showed significant raises of IgG2c and Total-IgG in all three vaccinated groups in comparison with the control group. Whereas, there were low concentrations of IgG1 in all immunization plans. Colony counts of mice spleen showed the bacterial load of PKF plan had the most decrease of bacterial load (DBL = 5 log10 CFU/g). Taken together, this evaluation indicated that PKF vaccination plan induced a polarized Th1 response and rendered an effective protection against bloodstream infection caused by A. baumannii.


Assuntos
Infecções por Acinetobacter/imunologia , Infecções por Acinetobacter/prevenção & controle , Acinetobacter baumannii/patogenicidade , Formação de Anticorpos/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Fatores R/sangue , Sepse/microbiologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Animais , Carga Bacteriana , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Clonagem Molecular , Modelos Animais de Doenças , Genes Bacterianos/genética , Imunização , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos C57BL , Fatores R/imunologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Baço/imunologia , Taxa de Sobrevida , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Fatores de Virulência/genética , Fatores de Virulência/imunologia
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