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1.
Clin Microbiol Rev ; 36(4): e0014822, 2023 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-37982596

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe and often fatal infections. MRSA epidemics have occurred in waves, whereby a previously successful lineage has been replaced by a more fit and better adapted lineage. Selection pressures in both hospital and community settings are not uniform across the globe, which has resulted in geographically distinct epidemiology. This review focuses on the mechanisms that trigger the establishment and maintenance of current, dominant MRSA lineages across the globe. While the important role of antibiotic resistance will be mentioned throughout, factors which influence the capacity of S. aureus to colonize and cause disease within a host will be the primary focus of this review. We show that while MRSA possesses a diverse arsenal of toxins including alpha-toxin, the success of a lineage involves more than just producing toxins that damage the host. Success is often attributed to the acquisition or loss of genetic elements involved in colonization and niche adaptation such as the arginine catabolic mobile element, as well as the activity of regulatory systems, and shift metabolism accordingly (e.g., the accessory genome regulator, agr). Understanding exactly how specific MRSA clones cause prolonged epidemics may reveal targets for therapies, whereby both core (e.g., the alpha toxin) and acquired virulence factors (e.g., the Panton-Valentine leukocidin) may be nullified using anti-virulence strategies.


Assuntos
Infecções Comunitárias Adquiridas , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus , Virulência , Antibacterianos , Exotoxinas/genética , Exotoxinas/metabolismo , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Fatores de Virulência/genética
2.
J Antimicrob Chemother ; 75(4): 903-906, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31971235

RESUMO

OBJECTIVES: To decipher the genetics of acquisition of carbapenemase-encoding genes identified in two carbapenem-resistant Enterobacteriaceae recovered from a single patient in Portugal. METHODS: Carbapenemase genes were searched by PCR assays and mating-out assays were performed to further characterize the plasmid support of the carbapenemase genes. Genetic characterization of the plasmid supports was performed by whole-plasmid sequencing using the Illumina technology. RESULTS: We identified here two NDM-1-producing isolates, namely a Morganella morganii and a Proteus mirabilis, sharing the same blaNDM-1-positive plasmid. This 154 kb plasmid belonged to the IncA/C2 type, recently renamed IncC, and co-harboured two AmpC ß-lactamase genes, namely blaCMY-4 and blaDHA-1, in addition to the 16S rRNA methylase gene armA encoding high-level resistance to aminoglycosides. In addition, the M. morganii isolate produced the CTX-M-33 extended-spectrum ß-lactamase possessing weak carbapenemase activity, encoded by another plasmid. CONCLUSIONS: We showed here that, in addition to KPC-type and OXA-181 carbapenemases, which have been identified as widespread in this country, another concern is the emergence of NDM-1-producing enterobacterial isolates in Portugal. We demonstrated here the in vivo plasmid transfer of a blaNDM-1-positive plasmid leading to dissemination of this carbapenemase gene within different enterobacterial species in a single patient.


Assuntos
Infecções por Enterobacteriaceae , Morganella morganii , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Infecções por Enterobacteriaceae/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Morganella morganii/genética , Plasmídeos/genética , Portugal , Proteus mirabilis/genética , RNA Ribossômico 16S , beta-Lactamases/genética
3.
Eur J Clin Microbiol Infect Dis ; 39(4): 783-790, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31873863

RESUMO

To evaluate the prevalence of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae fecal carriers at admission in a Portuguese hospital and to determine the epidemiology and antimicrobial resistance patterns of ESBL-producing isolates. During a 2-month period, rectal swabs were collected at hospital admission from 151 at-risk patients. In addition, 48 rectal swabs were obtained from weekly screenings of 37 patients hospitalized for > 48 h. All ESBL/carbapenemase-producing isolates were tested for antimicrobial susceptibility and characterized by PFGE and MLST. The prevalence of ESBL producers at hospital admission was 17% and 24% among at-risk patients hospitalized for > 48 h, while the prevalence of carbapenemase producers was 3% in both cases. Most of the isolates were Escherichia coli (54%) and Klebsiella pneumoniae (41%). The most common ESBL identified was CTX-M-15 (n = 17/34; 50%), followed by CTX-M-27 (n = 10; 29%), CTX-M-33 (n = 4; 12%), SHV-12 (n = 2), and CTX-M-55 (n = 1). The 20 E. coli isolates were distributed into 16 PFGE types and nine sequence types (ST), with 60% of the isolates belonging to ST131. The 15 K. pneumoniae were grouped into 12 PFGE types and nine STs, with three STs (ST17, ST449, ST147) corresponding to 60% of the isolates. A high proportion of isolates showed resistance to ciprofloxacin (86%), trimethoprim-sulfamethoxazole (68%), tobramycin (57%), and gentamicin (43%). All isolates remained susceptible to fosfomycin. A high prevalence of ESBL-producing Enterobacteriaceae was found at hospital admission among at-risk patients and > 50% of the isolates showed resistance to first-line antibiotics for the treatment of lower urinary tract infections, leaving fosfomycin as an alternative.


Assuntos
Portador Sadio/microbiologia , Farmacorresistência Bacteriana Múltipla , Infecções por Enterobacteriaceae/epidemiologia , Enterobacteriaceae/efeitos dos fármacos , Fezes/microbiologia , Intestinos/microbiologia , Antibacterianos/farmacologia , Portador Sadio/epidemiologia , Enterobacteriaceae/classificação , Infecções por Enterobacteriaceae/microbiologia , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Hospitalização , Humanos , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Testes de Sensibilidade Microbiana , Portugal/epidemiologia , Prevalência , Estudos Prospectivos , Reto/microbiologia , beta-Lactamases
4.
Emerg Infect Dis ; 25(9): 1632-1638, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31441424

RESUMO

We aimed to provide updated epidemiologic data on carbapenem-resistant Klebsiella pneumoniae in Portugal by characterizing all isolates (N = 46) recovered during 2013-2018 in a 123-bed hospital in Lisbon. We identified blaKPC-3 (n = 36), blaOXA-181 (n = 9), and blaGES-5 (n = 8) carbapenemase genes and observed co-occurrence of blaKPC-3 and blaGES-5 in 7 isolates. A single GES-5-producing isolate co-produced the extended-spectrum ß-lactamase BEL-1; both corresponding genes were co-located on the same ColE1-like plasmid. The blaOXA-181 gene was always located on an IncX3 plasmid, whereas blaKPC-3 was carried on IncN, IncFII, IncFIB, and IncFIIA plasmid types. The 46 isolates were distributed into 13 pulsotypes and 9 sequence types. All isolates remained susceptible to ceftazidime/avibactam, but some exhibited reduced antimicrobial susceptibility (MIC = 3 mg/L).


Assuntos
Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/isolamento & purificação , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Hospitais , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Testes de Sensibilidade Microbiana , Portugal/epidemiologia , beta-Lactamases/metabolismo
5.
Antimicrob Agents Chemother ; 63(12)2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31527021

RESUMO

CTX-M-type extended-spectrum ß-lactamases (ESBL) are widespread among Enterobacterales worldwide. The most common variant is CTX-M-15 hydrolyzing ceftazidime at high rate, but sparing carbapenems. We identified here CTX-M-33, a point mutant derivative of CTX-M-15 (Asp to Ser substitution at Ambler position 109), exhibiting a low carbapenemase activity. ß-Lactamase CTX-M-33 was identified in a Klebsiella pneumoniae isolate belonging to ST405, lacking the outer membrane protein OmpK36, that was resistant to broad-spectrum cephalosporins and ß-lactam/ß-lactamase inhibitor combinations, and displayed a decreased susceptibility to carbapenems. Comparative hydrolytic activity assays showed that CTX-M-33 hydrolyzed ceftazidime at a lower level than CTX-M-15, but significantly hydrolyzed meropenem. In addition, CTX-M-33 showed higher Mutant Prevention Concentration values and wider mutant selection window in presence of meropenem, in accordance with its observed hydrolytic properties. We identified here the very first CTX-M enzyme possessing a weak carbapenemase activity, that may correspond to an emerging phenomenon when considering its possibility to evolve from the widespread ESBL CTX-M-15.

6.
Eur J Clin Microbiol Infect Dis ; 38(11): 2037-2044, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31332610

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage is a major risk factor for infection, namely among populations in the community with inherent prompting factors, such as the homeless. In Portugal, there are no data on S. aureus/MRSA nasal carriage among the homeless community. A total of 84 homeless individuals living in Lisbon (34 with no permanent address and 50 living in shelter) were nasally screened for S. aureus/ MRSA. All isolates were characterized to determine antimicrobial susceptibility and clonal type. A total of 43 (51.2%) S. aureus carriers were identified, including a single individual colonized with MRSA (1.2%). S. aureus carriage rate was higher among individuals with no permanent address (58.8% versus 46%), younger (45.7 ± 12.7 versus 52.5 ± 10.8 years), and with diagnosis of asthma (9% versus 0%). The single MRSA belonged to the EMRSA-15 clone (PFGE D, ST15-SCCmec IVh, and spa type t790). Almost half of the methicillin-susceptible S. aureus (MSSA) isolates (41.9%, n = 18) belonged to two major clones, ST398-t1451 (n = 13) and ST30-t399/t11980/t12808 associated with PFGE I (n = 5). A high proportion of isolates showed non-susceptibility to mupirocin (64%), erythromycin (45%), and fusidic acid (20%) and induced resistance to clindamycin (39%). None of the isolates harboured PVL. Our results suggest that the homeless population of Lisbon does not constitute a reservoir of MRSA in the community, but harbour the highly transmissible ST398-t1451 MSSA lineage.


Assuntos
Portador Sadio/epidemiologia , Pessoas Mal Alojadas/estatística & dados numéricos , Cavidade Nasal/microbiologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/isolamento & purificação , Adulto , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , Portador Sadio/microbiologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Feminino , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Portugal/epidemiologia , Prevalência , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética
7.
Artigo em Inglês | MEDLINE | ID: mdl-29439957

RESUMO

Acquired 16S rRNA methylases (RMTases) conferring pan-drug resistance to aminoglycosides were searched among enterobacterial isolates recovered in Angola. A total of 36 hospitalized children were screened for rectal colonization using the Superaminoglycoside selective medium. Twenty-two pan-aminoglycoside-resistant enterobacterial isolates were recovered, all of which produced RMTases, i.e., RmtB, ArmA, and RmtC. Highly diverse genetic backgrounds were identified for Escherichia coli and Klebsiella pneumoniae isolates, most of which coproduced carbapenemases NDM-1 or NDM-5, respectively.


Assuntos
Proteínas de Bactérias/metabolismo , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , RNA Ribossômico 16S/metabolismo , beta-Lactamases/metabolismo , Aminoglicosídeos/farmacologia , Angola , Proteínas de Bactérias/genética , Criança , Criança Hospitalizada , Enterobacteriaceae/efeitos dos fármacos , Humanos , RNA Ribossômico 16S/genética , beta-Lactamases/genética
8.
Artigo em Inglês | MEDLINE | ID: mdl-29941640

RESUMO

The occurrence of resistance to last-resort antibiotics was evaluated among Enterobacteriaceae isolates recovered from hospitalized children in a remote African archipelago, São Tomé and Príncipe, where there is limited access to those antibiotics. Fifty patients were screened for colonization by carbapenem-, pan-aminoglycoside-, or polymyxin-resistant Enterobacteriaceae A total of 36 isolates (including 30 Escherichia coli and 4 Klebsiella pneumoniae) were recovered from 23 patients, including 26 isolates harboring the blaOXA-181 carbapenemase gene, a single isolate harboring the 16S rRNA methylase gene rmtB encoding pan-resistance to aminoglycosides, and 8 isolates coharboring both genes. A single isolate possessed the plasmid-borne colistin resistance gene mcr-1 A high clonal relationship was found for OXA-181-producing E. coli (4 clones), and conversely, three of the four OXA-181-producing K. pneumoniae isolates were clonally unrelated. This study overall showed a high prevalence of resistance to last-resort antibiotics in this country, where no epidemiological data were previously available.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/genética , Klebsiella pneumoniae/genética , Aminoglicosídeos/genética , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Colistina/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/genética , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Metiltransferases/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Polimixinas/farmacologia , RNA Ribossômico 16S/genética , São Tomé e Príncipe , beta-Lactamases/genética
9.
Emerg Infect Dis ; 23(12): 2023-2029, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29148380

RESUMO

The mcr-1 (mobile colistin resistance 1) gene, which encodes phosphoethanolamine transferase, has been recently identified as a source of acquired resistance to polymyxins in Escherichia coli. Using the SuperPolymyxin selective medium, we prospectively screened 100 pigs at 2 farms in Portugal for polymyxin-resistant Enterobacteriaceae and recovered 98 plasmid-mediated MCR-1-producing isolates. Most isolates corresponded to nonclonally related E. coli belonging to many sequence types; we also found 2 Klebsiella pneumoniae sequence types. The mcr-1 gene was carried on IncHI2 or IncP plasmid backbones. Our finding of a high rate of MCR-1 producers on 2 pig farms in Portugal highlights the diffusion of that colistin-resistance determinant at the farm level. The fact that the pigs received colistin as metaphylaxis in their feed during the 6 weeks before sampling suggests selective pressure.


Assuntos
Infecções por Escherichia coli/epidemiologia , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Transferência Genética Horizontal , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/genética , Proteínas de Membrana/genética , Animais , Antibacterianos/farmacologia , Colistina/farmacologia , Conjugação Genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/prevenção & controle , Infecções por Escherichia coli/transmissão , Proteínas de Escherichia coli/metabolismo , Fazendas , Dosagem de Genes , Expressão Gênica , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/prevenção & controle , Infecções por Klebsiella/transmissão , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/metabolismo , Proteínas de Membrana/metabolismo , Plasmídeos/química , Plasmídeos/metabolismo , Portugal/epidemiologia , Suínos
10.
Antimicrob Agents Chemother ; 60(10): 6189-92, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27503638

RESUMO

This study aimed to evaluate the prevalence of carbapenemase-producing Enterobacteriaceae in Luanda, Angola. A total of 157 rectal samples were collected from children visiting a pediatric hospital in Luanda in March 2015. Fifty-seven imipenem-nonsusceptible enterobacterial isolates were recovered, most of which were non-clonally related. The blaOXA-181 (50/57) and blaNDM-1 (7/57) carbapenemase genes were identified. Notably, OXA-181-producing Escherichia coli isolates rarely coproduced extended-spectrum ß-lactamases and consequently remained susceptible to broad-spectrum cephalosporins. The blaOXA-181 gene was always located on an IncX3 plasmid, while the blaNDM-1 gene was located on either IncFIA or IncA/C plasmids. The study identified a high prevalence of OXA-181 among hospitalized children in Angola.


Assuntos
Proteínas de Bactérias/genética , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/genética , beta-Lactamases/genética , Adolescente , Angola/epidemiologia , Proteínas de Bactérias/metabolismo , Criança , Pré-Escolar , Eletroforese em Gel de Campo Pulsado , Enterobacteriaceae/isolamento & purificação , Infecções por Enterobacteriaceae/epidemiologia , Proteínas de Escherichia coli/genética , Fezes/microbiologia , Hospitais , Humanos , Lactente , beta-Lactamases/metabolismo
11.
Antimicrob Agents Chemother ; 60(1): 678-81, 2016 01.
Artigo em Inglês | MEDLINE | ID: mdl-26552979

RESUMO

We assessed the prevalence of six biocide resistance genes among 82 methicillin-resistant Staphylococcus aureus (MRSA) and 219 methicillin-susceptible S. aureus (MSSA) isolates from three African countries; the prevalence was very high for sepA (95.3%), mepA (89.4%), and norA (86.4%), intermediate for lmrS (60.8%) and qacAB (40.5%), and low for smr (3.7%). A significant association between biocide resistance genes and antibiotic resistance was observed, and a new cutoff MIC of ≥1 mg/liter for chlorhexidine nonsusceptibility was defined.


Assuntos
Anti-Infecciosos Locais/farmacologia , Proteínas de Bactérias/genética , Clorexidina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Infecções Estafilocócicas/epidemiologia , Angola/epidemiologia , Ilhas Atlânticas/epidemiologia , Proteínas de Bactérias/metabolismo , Cabo Verde/epidemiologia , Expressão Gênica , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Prevalência , Infecções Estafilocócicas/microbiologia
12.
J Antimicrob Chemother ; 71(10): 2804-9, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27278899

RESUMO

OBJECTIVES: Recent surveillance of MRSA colonizing patients and healthcare workers in two African countries (Angola and São Tomé and Príncipe) reported the frequent recovery of oxacillin-susceptible MRSA (OS-MRSA): Staphylococcus aureus strains that gave positive results with the mecA DNA probe, but had low oxacillin MIC values characteristic of susceptible S. aureus. This apparent dissociation of the drug-resistant phenotype from mecA-the primary genetic determinant of resistance-prompted us to perform a more detailed analysis on nine of the African OS-MRSA strains. METHODS: Oxacillin MIC values were determined by Etest and population analysis profiles with and without induction of the stringent stress response by mupirocin. Biochemical profiling using SDS-PAGE followed by western blotting was used for the detection of PBP2A protein produced. RESULTS: Cultures of the African MRSA strains (ST88-IVa and ST8-V) showed heterogeneous oxacillin resistance in which the majority of cells exhibited low oxacillin MICs (≤0.75 mg/L), but highly resistant subpopulations were also present with oxacillin MIC values up to several hundred mg/L and with frequencies of 10(-4) to 10(-6). The same strains after induction of the stringent stress response by mupirocin 'converted' the heterogeneous phenotypes into a more homogeneous and higher level resistance. After induction by oxacillin and mupirocin, each of the nine African OS-MRSA strains produced PBP2A-the protein product of mecA. CONCLUSIONS: The resistant phenotype of OS-MRSA resembles the phenotypes of historically early MRSA clones. The nature of genetic determinants responsible for the heterogeneous phenotypes of OS-MRSA remains to be determined.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/biossíntese , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Oxacilina/farmacologia , Proteínas de Ligação às Penicilinas/biossíntese , África/epidemiologia , Angola/epidemiologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Eletroforese em Gel de Poliacrilamida , Monitoramento Epidemiológico , Humanos , Staphylococcus aureus Resistente à Meticilina/metabolismo , Testes de Sensibilidade Microbiana , Proteínas de Ligação às Penicilinas/genética , Fenótipo , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Resistência beta-Lactâmica/genética
13.
J Antimicrob Chemother ; 70(12): 3200-4, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26318189

RESUMO

BACKGROUND: Oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) isolates have been increasingly reported worldwide, but data regarding the African continent have not been available. METHODS: Between 2010 and 2014, 1462 inpatients and healthcare workers were screened for MRSA nasal carriage in São Tomé and Príncipe (STP) and Angola, two Portuguese-speaking African countries (PALOP countries). We determined the presence of the mecA gene and the antimicrobial susceptibility profiles of the isolates. OS-MRSA clonal lineages were identified as well as the presence of virulence determinants, including Panton-Valentine leucocidin (PVL). RESULTS: Out of 164 S. aureus hospital isolates tested, 29 (17.7%) were mecA positive, but susceptible to oxacillin, showing oxacillin MICs ≤3 mg/L. All OS-MRSA isolates were resistant to cefoxitin and most of them were also resistant to at least two antimicrobials other than ß-lactams. The 29 OS-MRSA were distributed into two major clonal lineages: (i) PFGE type B-ST88-SCCmec IVa, associated with spa types t186/t325/t786/t1814/t1951, detected in Angola (n = 5) and STP (n = 10); and (ii) PFGE type C-t451/t648-ST8-SCCmec V, exclusively found in STP (n = 9). OS-MRSA showed at least two virulence determinants. PVL was detected in an isolate recovered in STP. CONCLUSIONS: We describe a high prevalence of OS-MRSA among S. aureus strains recovered in two African countries. OS-MRSA in PALOP countries were mainly associated with ST88 and ST8, two prevalent MRSA clonal types in these countries. If direct testing for mecA is not available, cefoxitin susceptibility testing is highly recommended to avoid the misidentification of OS-MRSA.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Oxacilina/farmacologia , Proteínas de Ligação às Penicilinas/genética , Infecções Estafilocócicas/epidemiologia , Resistência beta-Lactâmica , Angola/epidemiologia , Ilhas Atlânticas/epidemiologia , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Genótipo , Pessoal de Saúde , Humanos , Pacientes Internados , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Tipagem Molecular , Prevalência , Infecções Estafilocócicas/microbiologia , Fatores de Virulência/genética
14.
Diagn Microbiol Infect Dis ; 105(2): 115864, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36502596

RESUMO

A rapid (<3 hours) and reliable multiplex PCR was developed for detecting simultaneously known plasmid-mediated fos genes conferring acquired resistance to fosfomycin. Our technique was tested on a collection of Escherichia coli isolates previously identified as bearing the fosA-, fosC- and fosL-like genes, showing a sensitivity and a specificity of 100%.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Infecções por Escherichia coli , Escherichia coli , Fosfomicina , Reação em Cadeia da Polimerase Multiplex , Humanos , Antibacterianos/farmacologia , beta-Lactamases/genética , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/diagnóstico , Fosfomicina/farmacologia , Testes de Sensibilidade Microbiana , Plasmídeos/genética
15.
Diagn Microbiol Infect Dis ; 107(3): 116058, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37657232

RESUMO

A rapid, easy-to-handle, cost-effective and universal culture-based test was developed for the identification of linezolid resistance among the most clinically relevant enterococcal and staphylococcal species. Our technique was tested using linezolid-resistant (n = 50) and linezolid-susceptible (n = 67) Gram-positive isolates: 34 Enterococcus faecium, 20 Enterococcus faecalis, 20 Staphylococcus aureus, 38 Staphylococcus epidermidis, and 5 Staphylococcus capitis. The susceptibility/resistance phenotype of E. faecium, E. faecalis, S. aureus, and S. epidermidis to linezolid was detected within 4.5 hours, while an extended timeframe was actually required for S. capitis (6.5 hours). The Rapid LNZ test showed a full agreement with the standard broth microdilution method, independently of the molecular resistance mechanism and MIC values, with sensitivities and specificities of 100% for all species.


Assuntos
Infecções por Bactérias Gram-Positivas , Oxazolidinonas , Humanos , Linezolida/farmacologia , Enterococcus , Antibacterianos/farmacologia , Staphylococcus , Staphylococcus aureus , Acetamidas , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana
16.
Microorganisms ; 11(2)2023 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-36838380

RESUMO

Bivalves are filter-feeding organisms and biomarkers of bacterial pollution. Our study aimed to analyze the occurrence and characteristics of extended-spectrum ß-lactamase (ESBL)- and carbapenemase-producing Escherichia coli among bivalves. A total of 522 bivalve samples were collected along Portuguese shellfish production areas. Homogenized samples were screened for E. coli contamination on corresponding selective plates, allowing for concomitant growth of Klebsiella pneumoniae. E. coli growth was observed in 39% of the samples. Subsequent selective screening identified nine samples (4.4%) contaminated with ESBL producers, corresponding to E. coli (n = 7) and K. pneumoniae (n = 2), while a single carbapenemase-producing K. pneumoniae (0.5%) was identified. ESBLs were all CTX-M-types commonly identified in human isolates, i.e., CTX-M-32 (n = 4), CTX-M-15 (n = 4), and CTX-M-14 (n = 1). The carbapenemase producer harbored the blaGES-5 gene located on a ColE plasmid. Clonality was evaluated by multilocus sequence typing, identifying E. coli backgrounds as ST10, ST23, ST540, ST617, ST746, SLV206, and SLV2325, commonly identified among environmental and human strains. The K. pneumoniae isolates belonged to ST834, ST15, and DLV644. The occurrence of ESBL- and carbapenemase-producing Enterobacteriaceae in bivalves reveals how the marine environment constitutes a reservoir of critical bacterial pathogens, thus potentially representing a risk to human health.

17.
J Glob Antimicrob Resist ; 35: 342-346, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37553021

RESUMO

OBJECTIVES: To evaluate the occurrence of plasmid-mediated fos genes among fosfomycin-resistant Escherichia coli isolates collected from patients in Lisbon, Portugal, and characterize the fos-positive strains. METHODS: A total of 19 186 E. coli isolates were prospectively collected between April 2022 and January 2023 from inpatients and outpatients at a private laboratory in Lisbon. Fosfomycin resistance was initially assessed by semi-automated systems and further confirmed by the disc diffusion method. Resistant isolates were investigated for plasmid-mediated fos genes (fosA1-fosA10, fosC and fosL1-fosL2) and extended-spectrum beta-lactamases (ESBLs) by PCR and sequencing. Multilocus sequence typing was performed to evaluate the clonal relationship among fos-carrying isolates. RESULTS: Out of the 19 186 E. coli isolates, 100 were fosfomycin-resistant (0.5%), out of which 15 carried a fosA-like gene (15%). The most prevalent fosfomycin-resistant determinant was fosA3 (n = 11), followed by fosA4 (n = 4). Among the 15 FosA-producing isolates, 10 co-produced an ESBL (67%), being either of CTX-M-15 (n = 8) or CTX-M-14 (n = 2) types. The fosA3 gene was carried on IncFIIA-, IncFIB-, and IncY-type plasmids, whereas fosA4 was always located on IncFIB-type plasmids. Most FosA4-producing isolates belonged to a single sequence type ST2161, whereas isolates carrying the fosA3 gene were distributed into nine distinct genetic backgrounds. CONCLUSION: The prevalence of fosfomycin-resistant E. coli isolates is still low in Portugal. Notably, 15% of fosfomycin-resistant isolates harbour a transferable fosA gene, among which there is a high rate of ESBL producers, turning traditional empirical therapeutical options used in Portugal (fosfomycin and amoxicillin-clavulanic acid) ineffective.


Assuntos
Infecções por Escherichia coli , Fosfomicina , Humanos , Fosfomicina/farmacologia , Escherichia coli/genética , Antibacterianos/farmacologia , Portugal/epidemiologia , Genes fos , Infecções por Escherichia coli/epidemiologia , DNA Bacteriano/genética , beta-Lactamases/genética , Plasmídeos/genética
18.
J Glob Antimicrob Resist ; 35: 137-142, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37709135

RESUMO

OBJECTIVES: Fosfomycin is a first-line treatment for uncomplicated urinary tract infections (UTIs) in several European countries, and it is increasingly becoming the treatment of choice globally. Resistance to fosfomycin in Escherichia coli can be exerted through several mechanisms, including the acquisition of fosfomycin-modifying enzymes, of which the FosA-type enzymes are the most common. This study analysed, both phenotypically and genotypically, an international collection of E. coli strains harbouring acquired fosA genes. METHODS: Thirty-one fosA-positive E. coli isolates were obtained from both clinical and environmental sources, from seven countries (Portugal (n = 12), Switzerland (n = 9), China (n = 3), France (n = 2), Nepal (n = 2), South Africa (n = 2), Kuwait (n = 1)). MICs were determined according to EUCAST guidelines. Whole genome sequencing (WGS) was performed on 23 isolates, and complete fosA plasmid sequences were determined for 12. Conjugation assays were performed on seven isolates. RESULTS: All isolates exhibited high-level resistance to fosfomycin (64 to >256 mg/L). WGS of 23 isolates identified 17 sequence types (STs), and 16 harboured fosA3, four fosA4, two fosA8, and one fosA10. ESBLs, pAmpC, or carbapenemase genes were present in 15, four, and three isolates, respectively. The fosA plasmids of 12 isolates were determined and were diverse in size (∼67 kb to ∼235 kb), resistance gene carriage, and replicon types. Six fosA plasmids additionally carried ESBL or carbapenemase genes. Conjugation assays, performed on seven isolates harbouring diverse plasmids, identified that all were capable of being transmitted. CONCLUSION: This study highlights the necessity of the surveillance and close monitoring of fosfomycin resistance in E. coli, essential to maintain the optimal use of this treatment option.


Assuntos
Infecções por Escherichia coli , Fosfomicina , Humanos , Fosfomicina/farmacologia , Escherichia coli , Antibacterianos/farmacologia , Infecções por Escherichia coli/epidemiologia , Farmacorresistência Bacteriana/genética , Plasmídeos/genética
19.
Antibiotics (Basel) ; 11(10)2022 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-36290025

RESUMO

Wild birds may be healthy carriers, and therefore, may be involved in the dissemination of clinically relevant antimicrobial-resistant bacteria, such as extended-spectrum ß-lactamases (ESBL) and carbapenemase-producing Enterobacteriaceae. This study evaluated whether urban pigeons living in five spots in Lisbon, Portugal, may be colonized and, therefore, constitute potential spreaders of multidrug-resistant bacteria. A total of 100 pigeon fecal samples were collected in different urban areas for the detection of ESBL- or carbapenemase-producing Enterobacteriaceae. All ß-lactamase-producing isolates were tested for antimicrobial susceptibility and their genetic backgrounds were characterized by multilocus sequence typing. Of the 100 fecal samples collected, nine ESBL-producing Escherichia coli (9%) were identified. Three isolates carried the blaCTX-M-15 gene, three isolates harbored the blaCTX-M-27 and three isolates carried the blaSHV-12 gene. Genotyping of the nine ESBL-producing E. coli strains revealed seven different sequence types (STs) including ST10, ST131, ST154, ST206, ST1488 (SLV ST10), ST2858 and ST3576, most of which have been already described in humans, animals or in the environment. Urban pigeons constitute a potential source of ESBL genes and may be a transmission vehicle of multidrug-resistant bacteria in the environment.

20.
Microorganisms ; 10(7)2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35889144

RESUMO

This study aimed to investigate, for the first time, the occurrence and characteristics of extended-spectrum ß-lactamase (ESBL)- and carbapenemase-producing Enterobacterales in Cape Verde. A total of 98 inpatients hospitalized at Hospital Universitário Agostinho Neto were screened for rectal colonization. All ESBL- and carbapenemase-producing isolates were tested for antimicrobial susceptibility and characterized by multilocus sequence typing. Mating-out assay followed by PCR-based replicon typing were performed to characterize the plasmids harboring carbapenemase encoding genes. A large proportion of patients carried ESBL- or carbapenemase-producing Enterobacterales (56% and 6%, respectively). Among 93 ESBL-producing isolates, there were mainly Klebsiella pneumoniae (58%) and Escherichia coli (37%). Five different ESBLs were detected, with CTX-M-15 being highly predominant (92%). Six carbapenemase-producing isolates (five E. coli and one K. pneumoniae) were recovered, and all of the OXA-48-like type (four OXA-181, one OXA-48, and one OXA-244). The blaOXA-48 gene was located on an IncFI-type plasmid, the blaOXA-181 gene on IncFI or IncX3 plasmids, and the blaOXA-244 gene was found to be chromosomally located. The five carbapenemase-producing E. coli isolates belonged to five distinct sequence types. This study overall showed a very high prevalence of ESBL-producing Enterobacterales, as well as the emergence of carbapenemase producers in this hospital.

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