Colistin has been extensively used since the middle of the last century in animals, particularly in swine, for the control of enteric infections. Colistin is presently considered the last line of ...defense against human infections caused by multidrug-resistant Gram-negative organisms such as carbapenemase-producer Enterobacterales, Acinetobacter baumanni, and Pseudomonas aeruginosa. Transferable bacterial resistance like mcr-genes was reported in isolates from both humans and animals. Researchers actively seek strategies to reduce colistin resistance. The definition of guidelines for colistin therapy in veterinary and human medicine is thus crucial. The ban of colistin use in swine as a growth promoter and for prophylactic purposes, and the implementation of sustainable measures in farm animals for the prevention of infections, would help to avoid resistance and should be encouraged. Colistin resistance in the human–animal–environment interface stresses the relevance of the One Health approach to achieve its effective control. Such measures should be addressed in a cooperative way, with efforts from multiple disciplines and with consensus among doctors, veterinary surgeons, and environment professionals. A revision of the mechanism of colistin action, resistance, animal and human use, as well as colistin susceptibility evaluation is debated here.
Microbes and Cancer: Friends or Faux? Azevedo, Maria Manuel; Pina-Vaz, Cidália; Baltazar, Fátima
International journal of molecular sciences,
04/2020, Volume:
21, Issue:
9
Journal Article
Peer reviewed
Open access
Cancer is one of the most aggressive and deadly diseases in the world, representing the second leading cause of death. It is a multifactorial disease, in which genetic alterations play a key role, ...but several environmental factors also contribute to its development and progression. Infections induced by certain viruses, bacteria, fungi and parasites constitute risk factors for cancer, being chronic infection associated to the development of certain types of cancer. On the other hand, susceptibility to infectious diseases is higher in cancer patients. The state of the host immune system plays a crucial role in the susceptibility to both infection and cancer. Importantly, immunosuppressive cancer treatments increase the risk of infection, by decreasing the host defenses. Furthermore, alterations in the host microbiota is also a key factor in the susceptibility to develop cancer. More recently, the identification of a tumor microbiota, in which bacteria establish a symbiotic relationship with cancer cells, opened a new area of research. There is evidence demonstrating that the interaction between bacteria and cancer cells can modulate the anticancer drug response and toxicity. The present review focuses on the interaction between microbes and cancer, specifically aiming to: (1) review the main infectious agents associated with development of cancer and the role of microbiota in cancer susceptibility; (2) highlight the higher vulnerability of cancer patients to acquire infectious diseases; (3) document the relationship between cancer cells and tissue microbiota; (4) describe the role of intratumoral bacteria in the response and toxicity to cancer therapy.
Azole fungal resistance is becoming a major public health problem in medicine in recent years. However, it was known in agriculture since several decades; the extensive use of these compounds results ...in contamination of air, plants, and soil. The increasing frequency of life-threatening fungal infections and the increase of prophylactical use of azoles in high-risk patients, taken together with the evolutionary biology evidence that drug selection pressure is an important factor for the emergence and spread of drug resistance, can result in a dramatic scenario. This study reviews the azole use in agricultural and medical contexts and discusses the hypothetical link between its extensive use and the emergence of azole resistance among human fungal pathogens.
Candida parapsilosis, an emergent agent of nosocomial infections, was previously made up of a complex of three genetically distinct groups (groups I, II, and III). Recently, the C. parapsilosis ...groups have been renamed as distinct species: C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis. In Portugal, no data pertaining to the distribution and antifungal susceptibility of these Candida species are yet available. In the present report, we describe the incidence and distribution of C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis among 175 clinical and environmental isolates previously identified by conventional methods as C. parapsilosis. We also evaluated the in vitro susceptibilities of the isolates to fluconazole, voriconazole, posaconazole, amphotericin B, and two echinocandins, caspofungin and anidulafungin. Of the 175 isolates tested, 160 (91.4%) were identified as C. parapsilosis sensu stricto, 4 (2.3%) were identified as C. orthopsilosis, and 5 (2.9%) were identified as C. metapsilosis. Six isolates corresponded to species other than the C. parapsilosis group. Interestingly, all isolates from blood cultures corresponded to C. parapsilosis sensu stricto. Evaluation of the antifungal susceptibility profile showed that only nine (5.6%) C. parapsilosis sensu stricto strains were susceptible-dose dependent or resistant to fluconazole, and a single strain displayed a multiazole-resistant phenotype; two (1.3%) C. parapsilosis sensu stricto strains were amphotericin B resistant. All C. orthopsilosis and C. metapsilosis isolates were susceptible to azoles and amphotericin B. A high number of strains were nonsusceptible to the echinocandins (caspofungin and anidulafungin).
Burn wound infections are often the source of bacteria responsible for systemic infections, including bloodstream infections and pneumonia that ultimately can result in multisystem organ failure and ...death. Any rapid change in the burn wound appearance or the clinical condition of the burn patient may herald burn wound infection or sepsis. The revival of phage therapy, either in single mode or in combination with conventional antibiotics may represent a valuable alternative, to treat specific bacterial infections such as burn wound infections, including those caused by multidrug-resistant organisms. This systematic review addresses the: 1) general characteristics of bacteriophages; 2) activity of bacteriophages vs conventional antibiotics; 3) activity of bacteriophages against biofilms; 4) bacteriophage administration; and 5) use of bacteriophages in burn wound infections. Although several scientific organizations/societies recognized that phage therapy could be of key value in modern wound care, specific aspects are critical for a burn surgeon and might represent pitfalls discouraging phage therapy adoption in burn wound management; in particular, the unavailability of consensual therapeutic guidelines/regulatory policies and the lack of laboratorial support that might be predictive of its efficacy. The availability of a product/formulation convenient to use, with adequate stability and shelf half-life is also a key condition.
The FASTinov flow cytometry kit, an ultrarapid antimicrobial susceptibility test, was directly evaluated on positive blood cultures (BC) at two sites: (i) FASTinov, S.A., in Porto, Portugal, using BC ...spiked with well-characterized bacteria, and (ii) Ramón y Cajal University Hospital in Madrid, Spain, using positive BC from patients. Two kits were evaluated, FAST
(
, Pseudomonas, Acinetobacter) and FAST
(Staphylococcus
). Dedicated software for cytometric data analysis and interpretative reporting, including both CLSI and EUCAST criteria, was used. The FAST
kit also provides information about the presence of resistant mechanisms, including extended-spectrum beta-lactamases (ESBLs) and carbapenemases. After 1 h of incubation at 37°C, bacteria were analyzed using a CytoFLEX cytometer (Beckman, CA). Disk diffusion was performed as the reference susceptibility method. Overall, 447 positive BC were included, 100 from hospitalized patients. Categorical agreement values for the FAST
panel were 96.8% based on EUCAST criteria and 96.4% based on CLSI criteria. For the FAST
panel, categorical agreement was 98.6% when using both criteria. When EUCAST criteria were used, the percentages of errors for the FAST
panel were 2.1% minor errors (mE), 1.3% major errors (ME), and 0.6% very major errors (VME). When CLSI criteria were used, 2.9% mE, 0.9% ME, and 0.4% VME were found. VME were mainly observed with amoxicillin-clavulanate, cefotaxime, ceftazidime, and gentamicin. The FAST
panel showed 0.3% mE, 1.4% ME, and 0.4% VME when EUCAST criteria were used (VME with respect to gentamicin and Staphylococcus) and 0.4% mE, 1.4% ME, and no VME when CLSI criteria were used. The FASTinov flow cytometry kits represent a rapid alternative for direct antimicrobial susceptibility testing from positive BC, showing time to results of <2 h, and can be used to personalize antibiotic and stewardship practices.
Numerous studies have explored the antibacterial properties of different types of honey from all around the world. However, the data available describing how honey acts against bacteria are few. The ...aim of this study was to apply a flow cytometry (FC) protocol to examine and characterize the primary effects of three varieties of honey (avocado, chestnut and polyfloral) upon physiological status of
and
cells to reveal their antibacterial action mechanisms. The effects of honey samples on membrane potential, membrane integrity, and metabolic activity were assessed using different fluorochromes, in a 180 min time course assay. Time-kill experiments were also carried out under similar conditions. Exposure of
and
to the distinct honey samples resulted in physiological changes related to membrane polarization and membrane integrity. Moreover, honey induced a remarkable metabolic disruption as primary physiological effect upon
. The different honey samples induced quite similar effects on both bacteria. However, the depth of bacteria response throughout the treatment varied depending on the concentration tested and among honey varieties, probably due to compositional differences in the honey.
Urinary tract infection (UTI) is a common complication after kidney transplantation, often associated to graft loss and increased healthcare costs. Kidney transplant patients (KTPs) are particularly ...susceptible to infection by Enterobacteriaceae-producing extended-spectrum β-lactamases (ESBLs). A retrospective case-control study was conducted to identify independent risk factors for ESBL-producing Escherichia coli and Klebsiella pneumoniae in non-hospitalized KTPs with UTI. Forty-nine patients suffering from UTI by ESBL-producing bacteria (ESBL-P) as case group and the same number of patients with UTI by ESBL negative (ESBL-N) as control-group were compared. Clinical data, renal function parameters during UTI episodes, UTI recurrence and relapsing rate, as well as risk factors for recurrence, molecular characterization of isolates and the respective antimicrobial susceptibility profile were evaluated. Diabetes mellitus (p <0.007), previous antibiotic prophylaxis (p=0.017) or therapy (p<0.001), previous UTI (p=0.01), relapsing infection (p=0.019) and patients with delayed graft function after transplant (p=0.001) represented risk factors for infection by ESBL positive Enterobacteriaceae in KTPs. Interestingly, the period of time between data of transplantation and data of UTI was shorter in case of ESBL-P case-group (28.8 months) compared with ESBL-N control-group (50.9 months). ESBL-producing bacteria exhibited higher resistance to fluoroquinolones (p=0.002), trimethoprim-sulfamethoxazole (p<0.001) and gentamicin (p<0.001). Molecular analysis showed that blaCTX-M was the most common ESBL encoding gene (65.3%), although in 55.1% of the cases more than one ESBL gene was found. In 29.4% of K. pneumoniae isolates, three bla-genes (blaCTX-M-blaTEM-blaSHV) were simultaneously detected. Low estimated glomerular filtration rate (p=0.009) was found to be risk factor for UTI recurrence. Over 60% of recurrent UTI episodes were caused by genetically similar strains. UTI by ESBL-producing Enterobacteriaceae in KTPs represent an important clinical challenge regarding not only hospitalized patients but also concerning outpatients.
FASTinov® developed a rapid antimicrobial susceptibility test that includes the purification of a bacterial suspension directly from positive blood cultures (BC). In order to streamline laboratory ...workflow, the use of the bacterial suspension obtained through FASTinov® sample
prep
was tested for identification (ID) by matrix absorption laser deionization–time of flight mass spectrometry (MALDI-TOF MS) (Bruker) in 364 positive BC, and its accuracy assessed comparing with the MALDI-TOF MS ID of the next-day subcultured colonies. FASTinov sample
prep
was highly reliable for rapid ID directly from BC with proportion of agreement of 94.9% for Gram-positive and 96.3% for Gram-negative bacteria.
Candida parapsilosis is the second most prevalent fungal agent causing bloodstream infections. Nevertheless, there is little information about the molecular mechanisms underlying azole resistance in ...this species. Mutations (G1747A, A2619C, and A3191C) in the MRR1 transcription factor gene were identified in fluconazole- and voriconazole-resistant strains. Independent expression of MRR1 genes harboring these mutations showed that G1747A (G583R) and A2619C (K873N) are gain-of-function mutations responsible for azole resistance, the first described in C. parapsilosis.
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