The global spread of carbapenem-resistant Acinetobacter baumannii (A. baumannii) strains has restricted the therapeutic options available to treat infections due to this pathogen. Understanding the ...prevalence of such infections and the underlying genetic mechanisms of resistance may help in the implementation of adequate measures to control and prevent acquisition of nosocomial infections, especially in an intensive care unit setting. This study describes the molecular characteristics and risk factors associated with OXA-23-producing A. baumannii infections. A case-control study was undertaken from September/2013 to April/2015. Acquisition of OXA-23-producing A. baumannii was found to be associated with the use of nasogastric tubes, haemodialysis, and the use of cephalosporins. These isolates were only susceptible to amikacin, gentamicin, tigecycline, and colistin, and contained the ISAba1 insertion sequence upstream ofblaOXA-23 and blaOXA-51 genes. Twenty-six OXA-23-producing A. baumannii strains belonged to the ST79 (CC79) clonal group,and patients infected or colonised by these isolates had a higher mortality rate (34.6%). In conclusion, this study showed a dissemination of OXA-23-producing A. baumannii strains that was associated with several healthcare-related risk factors and high mortality rates among intensive care unit patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Brazil is recognized for its biodiversity and the genetic variability of its organisms. This genetic variability becomes even more valuable when it is properly documented and accessible. ...Understanding bacterial diversity through molecular characterization is necessary as it can improve patient treatment, reduce the length of hospital stays and the selection of resistant bacteria, and generate data for health and epidemiological surveillance. In this sense, in this study, we aimed to understand the biodiversity and molecular epidemiology of carbapenem-resistant bacteria in clinical samples recovered in the state of Rondônia, located in the Southwest Amazon region. Retrospective data from the Central Public Health Laboratories (LACEN/RO) between 2018 and 2021 were analysed using the Laboratory Environment Manager Platform (GAL). Seventy-two species with carbapenem resistance profiles were identified, of which 25 species carried at least one gene encoding carbapenemases of classes A (bla
-like), B (bla
-like, bla
-like or bla
-like) and D (bla
-like, bla
-like, bla
-like, bla
-like or bla
-like), among which we will highlight Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Serratia marcescens, and Providencia spp. With these results, we hope to contribute to the field by providing epidemiological molecular data for state surveillance on bacterial resistance and assisting in public policy decision-making.
Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food ...investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCCmec typing and detection of mecA, vanA, vanB, and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25–1 μg/mL) and teicoplanin (MICs <0.25–4 μg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured blaZ gene. Seven (43.8 %) isolates carried mecA; and among them, the SCCmec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb, see, seg, sej, sem, etb, tsst, pvl, and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America.
•The CoNS isolates reported in this study harboured blaZ and virulence genes.•Biofilm-forming methicillin-resistant CoNS harbouring mecA gene were recovered.•SCCmec Type III was the most predominant among mecA-positive CoNS isolates.•CoNS with inducible clindamycin resistance phenotype (MLS-B) were reported.
Carbapenem resistance in Acinetobacter baumannii is a public health issue globally, mainly due to the production of carbapenem hydrolyzing class D β-lactamases (CHDLs). In Brazil, OXA-23 and OXA-143 ...CHDLs have been prevalent in A. baumannii from clinical settings, with some OXA-23 reports in the environmental samples, whereas OXA-72 has begun to be increasingly reported. This study aims to perform the genomic and microbiological characterization of carbapenem-resistant A. baumannii isolates recovered from migratory birds and captive birds inhabiting a lake within a Brazilian Zoo. Four hundred and eighty-one gram-negative bacilli were recovered from choanal and cloacal swabs obtained from 50 migratory birds and 37 captive birds present at the zoo's lake between July and August of 2012. Among all GNB, nine OXA-72-producing A. baumannii were detected from the microbiota of four migratory and five captive aquatic birds. The OXA-72-producing A. baumannii isolates were submitted to antimicrobial susceptibility test and PFGE, exhibiting a multidrug-resistant profile and clonal relatedness with OXA-72-positive human isolates circulating for eighteen years in a hospital setting. MLST, plasmid analysis and whole-genome sequencing revealed which all carbapenem-resistant A. baumannii from bird and human hosts belonged to clonal complex 79, and harboured a small plasmid (⁓16.6-kb in size), named pAC1-BRL, which carried blaOXA-72 gene, macrolide resistance genes msrE and mphE, and the toxin-antitoxin system AbkAB. To determine the impact of pAC1-BRL acquisition in the the capacity of a microorganism to survive in a competitive environment (in the following called fitness), the laboratory strain A. baumannii ATCC 19606 was used in the fitness experiments and suggested an increase of its relative fitness after the pAC1-BRL acquisition. In summary, the detection of OXA-72-producing A. baumannii strains belonging to CC79 in aquatic birds is a piece of epidemiological evidence demonstrating that dissemination of high-risk bacteria is extending beyond the hospital.
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•Occurrence of MDR bacteria in aquatic birds in a zoo has been investigated.•OXA-72-producing A. baumannii belonged to CC79 was identified in birds and humans.•The blaOXA-72 gene was carried by a new GR2-type small plasmid.•Birds as routes of MDR A. baumannii spread beyond the hospital is discussed.
The emergence and rapid dissemination of colistin-resistant
carrying the plasmid-mediated
gene have created an urgent need to develop specific screening methods. In this study, we evaluated four ...assays based on the inhibition of MCR-1 activity by EDTA: (i) a combined-disk test (CDT) comparing the inhibition zones of colistin and colistin (10 μg) plus EDTA (100 mM); (ii) reduction of colistin MIC (CMR) in the presence of EDTA (80 μg/ml); (iii) a modified rapid polymyxin Nordmann/Poirel test (MPNP); and (iv) alteration of zeta potential (R
= ZP
/ZP
). We obtained encouraging results for the detection of MCR-1 in
isolates recovered from human, food, and animal samples, using the following assay parameters: ≥3 mm difference in the inhibition zones between colistin disks without and with EDTA; ≥4-fold colistin MIC decrease in the presence of EDTA; R
of ≥2.5; and the absence of metabolic activity and proliferation, indicated by unchanged color of phenol red in the presence of colistin-EDTA, in the MPNP test. In this regard, the CDT, CMR, R
, and MPNP assays exhibited sensitivities of 96.7, 96.7, 95.1, and 96.7% and specificities of 89.6, 83.3, 100, and 100%, respectively, for detecting MCR-1-positive
Our results demonstrate that inhibition by EDTA and zeta potential assays may provide simple and inexpensive methods for the presumptive detection of MCR-1-producing
isolates in human and veterinary diagnostic laboratories.
Abstract A total of 31 unrelated OXA-23–producing Acinetobacter baumannii strains isolated from 14 hospitals located in distinct Brazilian regions were evaluated in this study. These isolates were ...grouped into 12 different sequence types (STs), of which 7 had unique allelic sequences (ST188, ST189, ST190, ST191, ST192, ST228, and ST299). Most isolates belonged to the clonal complex CC79 followed by CC15 and CC1. Only polymyxin B and minocycline showed good activity against the OXA-23–producing A. baumannii clones. The IS Aba1 upstream blaOXA-23 , blaOXA-51 –like, or ampC was found in 100%, 54.8%, and 77.4% of the isolates, respectively. High resistance rates to ceftazidime and cefotaxime were observed among those isolates possessing IS Aba1 upstream ampC , in contrast to those isolates that did not carry this configuration. Moreover, a ≥2 Log2 decrease in the MICs of meropenem and ceftazidime was observed in the presence of phenyl-arginine-β-naphthylamide for 80.6% and 54.8% of isolates, respectively. Overexpression of the adeB was observed in 61.3% of isolates, particularly among those isolates belonging to the ST1 (CC1). It was also verified that ompW was down-regulated in all isolates belonging to the ST15 (CC15). On the other hand, carO and omp33-36 genes were overexpressed in 48.4% and 58.1% of the isolates, respectively. In this study, we show that overexpression of AdeABC system could significantly contribute for resistance to meropenem and ceftazidime among OXA-23–producing A. baumannii clones in Brazil, demonstrating the complexity involved in the β-lactam resistance in such isolates.
Objective
The identification of
Candida
spp. in denture stomatitis, the clinical manifestations, and the antifungal susceptibility profile lead to a correct and individualized therapeutic management ...of the patients. This study is aimed at investigating the clinical manifestations and epidemiological and microbiological characteristics of
Candida
-associated denture stomatitis.
Design
The samples were obtained by swabbing the oral mucosa of the subjects and then seeded onto Sabouraud Dextrose Agar and onto CHROMagar®
Candida
plates. The identification at the species level was confirmed by Matrix Assisted Laser Desorption Time of Flight Mass Spectrometry. Clinical classification was performed according to the criteria proposed by Newton (1962): (i) pinpoint hyperemia, (ii) diffuse hyperemia, and (iii) granular hyperemia. For carrying out the antifungal susceptibility testing, we adopted the CLSI M27-S4 protocol.
Results
C. albicans
was the most prevalent species in our study. Regarding non-
albicans Candida
species,
C. glabrata
was the most common species isolated from the oral mucosa (
n
= 4, 14.8%), while in the prosthesis, it was
C. tropicalis
(
n
= 4, 14.8%). The most prevalent clinical manifestation was pinpoint hyperemia and diffuse hyperemia.
Candida albicans
,
C. glabrata
, and
C. parapsilosis
were susceptible to all the tested antifungals. Concerning fluconazole and micafungin, only two strains showed dose-dependent sensitivity (minimum inhibitory concentration (MIC), 1 μg/mL) and intermediate sensitivity (MIC, 0.25 μg/mL). One
C. tropicalis
strain was resistant to voriconazole (MIC, 8 μg/mL).
Conclusions
C. albicans
was the most common species found in oral mucosa and prosthesis. The tested antifungal drugs showed great activity against most isolates. The most prevalent clinical manifestations were Newton’s type I and type II.
Carbapenem-resistant
(CRAB) are emerging worldwide. In South America, clinical isolates presenting such a phenotype usually do not belong to the globally distributed international clone 2 (IC2). The ...majority of these isolates are also resistant to multiple other antimicrobials and are often designated extremely drug-resistant (XDR). The aim of this study was to characterize the resistance mechanisms presented by 18 carbapenem-resistant
isolates from five different Brazilian hospitals. Species identification was determined by
sequencing, and antimicrobial susceptibility was determined by broth microdilution. Isolates were submitted to whole genome sequencing using Illumina platform and genetic similarity was determined by PFGE, MLST, and cgMLST. Genome analysis was used to identify intrinsic and acquired resistance determinants, including mutations in the AdeRSABC efflux system and in outer membrane proteins (OMPs). All isolates were identified as
and grouped into 4 pulsotypes by PFGE, which belonged to clonal complexes (CC) 15
/103
(
= 4) and 79
/113
(
= 14), corresponding to IC4 and IC5, respectively. High MIC values to carbapenems, broad-spectrum cephalosporins, amikacin, and ciprofloxacin were observed in all isolates, while MICs of ampicillin/sulbactam, gentamicin, and tigecycline varied among the isolates. Minocycline was the most active antimicrobial agent tested. Moreover, 12 isolates (66.7%) were considered resistant to polymyxins. Besides intrinsic OXA-51 and ADC variants, all isolates harbored an acquired carbapenem-hydrolyzing class D β-lactamase (CHDL) encoding gene, either
or
. A diversity of aminoglycoside modifying enzymes and resistance determinants to other antimicrobial classes were found, as well as mutations in
and
. Non-synonymous mutations have also been identified in the AdeRSABC efflux system and in most OMPs, but they were considered natural polymorphisms. Moreover, resistance to polymyxins among isolates belonging to IC5 were associated to non-synonymous mutations in
, but no known polymyxin resistance mechanism was identified in isolates belonging to IC4. In conclusion,
clinical isolates belonging to South America's major clones present a myriad of antimicrobial resistance determinants. Special attention should be paid to natural polymorphisms observed in each clonal lineage, especially regarding non-synonymous mutations in constitutive genes associated with distinct resistance phenotypes.
•An increase (30.6%) of PMB resistance rates was observed among K. pneumoniae isolates recovered from blood cultures.•The PMB-R-KPN isolates were classified as XDR (83.3%), MDR (13.9%), or PDR ...(2.8%).•The blaKPC-2 gene was detected in 28 of 36 (77.8%) PMB-R-KPN isolates. Most PMB-R-KPN belonged to the ST258 (55.6%), followed by ST437 (27.8%).•A C7/ST258/XDR clone also carrying blaCTX-M-14 and rmtB-1 was introduced in 2014.•Twelve of 36 (33.3%) PMB-R-KPN isolates showed disruption of mgrB.
The polymyxins have become one of the last resorts to treat serious infections caused by KPC-2-producing Klebsiella pneumoniae worldwide. However, the increase of polymyxin consumption has favored the emergence of resistance to these compounds. In this study, we observed an increase in polymyxin B resistance rates from 0 to 30.6% among 224 K. pneumoniae isolates recovered from blood cultures between 2009 and 2015. Only gentamicin, tigecycline and fosfomycin remained active against the polymyxin B-resistant K. pneumoniae (PMB-R-KPN) isolates, which were classified as extensively drug-resistant (XDR; 83.3%), multidrug-resistant (MDR; 13.9%), or pan-drug resistant (2.8%). Most PMB-R-KPN clones belonged to CC258 (ST11, ST258, ST340, and ST437). A C7/ST258 XDR clone carrying distinct resistance determinants (blaSHV-11, blaTEM-1, blaCTX-M-15, blaCTX-M-14, blaKPC-2, and rmtB-1) was introduced in 2014. Twelve of 36 PMB-R-KPN isolates showed disruption of mgrB. No mcr–1–positive isolate was found. The rapid detection of PMB-R-KPN isolates allied to implementation of effective infection control measures are of crucial importance to avoid the dissemination of high-risk PMB-R-KPN clones.
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