Pseudomonas aeruginosa is a major, but opportunistic, respiratory pathogen, which rarely infects healthy individuals, mainly due to the barrier effect of the human airway epithelium (HAE). This ...review explores the interaction of P. aeruginosa with HAE and the progression of the infection. The basolateral part of the epithelium, which includes the basolateral membrane of the epithelial cells and the basement membrane, is inaccessible in normal tight epithelia with intact junctions. We highlight how P. aeruginosa exploits weaknesses in the HAE barrier to gain access to the basolateral part of the epithelium. This access is crucial to initiate respiratory infection and is mainly observed in the injured epithelium, in repairing or chronically remodeled epithelium, and during extrusion of senescent cells or cell multiplication during normal epithelium renewal. The subsequent adhesion of the bacteria and cytotoxic action of virulence factors, including the toxins delivered by the type 3 secretion system (T3SS), lead to retractions and cell death. Eventually, P. aeruginosa progressively reaches the basement membrane and propagates radially through the basal part of the epithelium to disseminate using twitching and flagellar motility.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Training for mastering FilmArray Pneumonia Panel by the intensivists is required for successful utilization in the daily routine practice.•FilmArray Pneumonia Panel should be preferably performed on ...bronchoalveolar lavage to avoid over-diagnosis of bacterial coinfection.•Conventional culture should be systematically performed in parallel of a FilmArray Pneumonia Panel.•Therapeutic decision must be re-evaluated with the result of 2-days conventional culture.
The FilmArray Pneumonia Panel has proven to be an effective tool for rapid detection of main respiratory pathogens. However, its rational use needs appropriate knowledge and formation regarding its indication and interpretation. Herein, we provide some advices to help with success of its daily routine use, particularly in critically ill ventilated COVID-19 patients.
Clinical Trial registration number: NCT04453540.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To assess the aetiology, clinical features, diagnostic studies and outcomes of community-acquired pneumonia (CAP) in a French cohort of hospitalized kidney transplant recipients.
We performed a ...retrospective, multicentre study in kidney transplant recipients admitted to ten French centres for CAP from January 2016 to December 2018. CAP discharge diagnoses were clinically and radiologically validated. We assessed a descriptive analysis of all confirmed CAP including medical ward and intensive care unit admissions.
One hundred sixty-five CAP episodes in 132 patients were included. Median time from transplantation to admission was 6.4 (interquartile range, 1.6–12.3) years, with corticosteroid exposure in 112/165 (67.9%) cases. Sputum culture was performed in 47/165 (28.5%) cases including 7/47 (14.9%) positive samples. Bronchoscopy was performed in 87/165 (52.7%) cases with pathogens identified in 39/87 (44.8%) cases. Microbiological studies led to identifying a respiratory pathogen in 64/165 (38.8%) CAP episodes including 11/64 (17.2%) polymicrobial cases. Among these 64 episodes, 75 microorganisms were identified; 46/75 (61.3%) were core respiratory pathogens and 29/75 (38.7%) were opportunistic or drug-resistant organisms including Pneumocystis jirovecii 9/75 (12%), Pseudomonas aeruginosa 5/75 (6.7%), multidrug-resistant Enterobacteriaceae 4/75 (5.3%), and Aspergillus 4/75 (5.3%). Patients required intensive care unit admission in 26/165 (15.8%) episodes, invasive ventilation in 20/165 (12.1%) cases, and 22/165 (13.3%) needed in-hospital dialysis.
CAP episodes occurred in kidney transplant recipients with a long history of immunosuppressive drug exposure. Diagnostic studies identified a microorganism in more than one-third of CAP episodes, including drug-resistant and opportunistic pathogens.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The antibacterial oxidative response, which relies on the production of hydrogen peroxide (H.sub.2 O.sub.2) and hypothiocyanite (OSCN.sup.- ), is a major line of defense protecting the human airway ...epithelium (HAE) from lesions when infected. The in vitro studies of the oxidative responses are performed mainly by one-shot H.sub.2 O.sub.2 exposure that does not recapitulate the complex H.sub.2 O.sub.2 /LPO/SCN.sup.- system releasing the reactive oxygen species in airway secretions. A cell-free in vitro assay mimicking this system has been described but was not fully characterized. Here, we comprehensively characterized the hourly H.sub.2 O.sub.2 /OSCN.sup.- concentrations produced within this in vitro assay and assessed the resistance of Pseudomonas aeruginosa and Staphylococcus aureus clinical strains to the HAE oxidative response. We found that H.sub.2 O.sub.2 /OSCN.sup.- were steadily produced from 7h and up to 25h, but OSCN.sup.- was detoxified in 15 minutes by bacteria upon exposure. Preliminary tests on PA14 showed survival rates at 1-hour post-exposure (hpe) to H.sub.2 O.sub.2 of roughly 50% for 10.sup.5 and 10.sup.7 colony-forming unit (CFU)/mL inocula, while 10.sup.2 and 10.sup.4 CFU/mL inocula were cleared after one hpe. Thirteen clinical strains were then exposed, highlighting that conversely to P. aeruginosa, S. aureus showed resistance to oxidative stress independently of its antibiotic resistance phenotype. Our results demonstrated how this in vitro assay can be helpful in assessing whether pathogens can resist the antibacterial oxidative HAE response. We anticipate these findings as a starting point for more sophisticated in vitro models that could serve as high-throughput screening for molecules targeting the bacterial antioxidant response.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Characterization genetic determinants with fluoroquinolone (enrofloxacin) resistance.•Non-duplicate Enterobacteriaceae across EU from dogs and cats in the ComPath program.•Among 20% PMQR-positive ...strains, qnr including qnrD in Proteeae, was predominant.•Of 80% non-PMQR strains, 1–4 mutations in gyrA, gyrB and parC were detected.•Gyrase mutations played a markedly greater role than PMQR in mediating resistance.
ComPath is an ongoing European programme dedicated to monitor antibiotic susceptibility of bacterial pathogens from diseased dogs and cats. The objective was to characterize determinants associated with quinolone resistance among 160 enrofloxacin non-wild type strains (100 Escherichia coli, 45 Proteus mirabilis, 14 Klebsiella pneumoniae, 1 Enterobacter cloacae) selected among 843 non-duplicate Enterobacteriaceae isolates collected in 12 European countries (2013–2014). These strains with non-wild type MICs of ≥0.25 mg/L, for P. mirabilis ≥0.5 mg/L, were screened for PMQR determinants (qnr, oqxAB, qepA and aac(6′)-Ib-cr), and for QRDR mutations in gyrA, gyrB, parC and parE genes.
Among them, 20% (32/160) carried at least one PMQR (18/32 qnrB, qnrS or qnrD, 10/32 aac(6′)-Ib-cr and 13/32 oqxAB), and 80% (128/160) no PMQR. qnrB was detected in 3 E. coli, 2 K. pneumoniae and 1 E. cloacae strains; qnrS in 6 E. coli and 1 P. mirabilis and aac(6′)-Ib-cr in 4 E. coli, 5 K. pneumoniae and 1 E. cloacae strains. All qnrD1 were detected in P. mirabilis. oqxAB was detected in 12/14 K. pneumoniae and 1 E. cloacae. No qepA genes were detected. From the 32 PMQR-positive strains, 10 showed enrofloxacin MICs ≤2 mg/L and 22 MICs ≥8 mg/L, the latter carrying 1–4 mutations in QRDR. For the 128 non-PMQR strains, 37 showed enrofloxacin MICs ≤2 mg/L with 0–2 QRDR mutations, and 91 MICs ≥4 mg/L carrying 1–4 QRDR mutations. In conclusion, qnr was the major PMQR and qnrD only detected in Proteeae. Mutations in QRDR play a markedly greater role in mediating fluoroquinolone resistance than PMQR.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
An important question regarding the biologic implications of antibiotic-resistant microbes is how resistance impacts the organism’s overall fitness and virulence. Currently it is generally thought ...that antibiotic resistance carries a fitness cost and reduces virulence. For the human pathogen Pseudomonas aeruginosa , treatment with carbapenem antibiotics is a mainstay of therapy that can lead to the emergence of resistance, often through the loss of the carbapenem entry channel OprD. Transposon insertion-site sequencing was used to analyze the fitness of 300,000 mutants of P. aeruginosa strain PA14 in a mouse model for gut colonization and systemic dissemination after induction of neutropenia. Transposon insertions in the oprD gene led not only to carbapenem resistance but also to a dramatic increase in mucosal colonization and dissemination to the spleen. These findings were confirmed in vivo with different oprD mutants of PA14 as well as with related pairs of carbapenem-susceptible and -resistant clinical isolates. Compared with OprD ⁺ strains, those lacking OprD were more resistant to killing by acidic pH or normal human serum and had increased cytotoxicity against murine macrophages. RNA-sequencing analysis revealed that an oprD mutant showed dramatic changes in the transcription of genes that may contribute to the various phenotypic changes observed. The association between carbapenem resistance and enhanced survival of P. aeruginosa in infected murine hosts suggests that either drug resistance or host colonization can cause the emergence of more pathogenic, drug-resistant P. aeruginosa clones in a single genetic event.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The increase in emerging drug resistant Gram-negative bacterial infections is a global concern. In addition, there is growing recognition that compromising the microbiota through the use of ...broad-spectrum antibiotics can impact long term patient outcomes. Therefore, there is the need to develop new bactericidal strategies to combat Gram-negative infections that would address these specific issues. In this study, we report and characterize one such approach, an antibody-drug conjugate (ADC) that combines (i) targeting the surface of a specific pathogenic organism through a monoclonal antibody with (ii) the high killing activity of an antimicrobial peptide. We focused on a major pathogenic Gram-negative bacterium associated with antibacterial resistance:
Pseudomonas aeruginosa
. To target this organism, we designed an ADC by fusing an antimicrobial peptide to the C-terminal end of the V
H
and/or V
L
-chain of a monoclonal antibody, VSX, that targets the core of
P
.
aeruginosa
lipopolysaccharide. This ADC demonstrates appropriately minimal levels of toxicity against mammalian cells, rapidly kills
P
.
aeruginosa
strains, and protects mice from
P
.
aeruginosa
lung infection when administered therapeutically. Furthermore, we found that the ADC was synergistic with several classes of antibiotics. This approach described in this study might result in a broadly useful strategy for targeting specific pathogenic microorganisms without further augmenting antibiotic resistance.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Nalidixic acid resistant E. coli occur in imported breeding animals and their progeny.•Quinolone resistant E. coli has spread vertically through the broiler pyramid.•Incidence of quinolone resistant ...E. coli is likely effected by on farm recirculation.•The mechanism for quinolone resistance was a single mutation in the gyrA gene.
During recent years a rapid increase of quinolone resistant Escherichia coli have been noted in the Swedish broiler population, despite the lack of a known selective pressure. The current study wanted to investigate if imported breeding birds could be a source for the quinolone resistant E. coli. The occurrence of quinolone resistant E. coli was investigated, using selective cultivation with nalidixic acid, in grand-parent birds on arrival to Sweden and their progeny. In addition, sampling in hatcheries and empty cleaned poultry houses was performed. Clonality of isolates was investigated using a 10-loci multiple-locus variable number tandem repeat analysis (MLVA). To identify the genetic basis for the resistance isolates were also analysed for occurrence of plasmid-mediated quinolone resistance (PMQR) determinants and characterization of chromosomal mutations. E. coli resistant to nalidixic acid occurred in grandparent birds imported to Sweden for breeding purposes. Four predominant MLVA types were identified in isolates from grandparent birds, parent birds and broilers. However, resistant E. coli with identical MLVA patterns were also present in hatcheries and poultry houses suggesting that the environment plays a role in the occurrence. Nalidixic acid resistance was due to a mutation in the gyrA gene and no PMQR could be identified. The occurrence of identical clones in all levels of the production pyramid points to that quinolone resistant E. coli can be introduced through imported breeding birds and spread by vertical transmission to all levels of the broiler production pyramid.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The aim of this study was to investigate the resistance mechanisms of carbapenem-resistant Enterobacteriaceae clinical strains recovered from Al Thawra University Hospital, Sana'a, Yemen.
A total of ...27 isolates showing decreased susceptibility to carbapenems were obtained from different clinical specimens in Al Thawra Hospital, Sana'a, Yemen. Strains were identified by Matrix Assisted Laser Desorption Ionization Time-Of-Flight spectroscopy. Susceptibility to antibiotics was determined by the disk diffusion method on Mueller Hinton agar. Carbapenemases-encoding genes, extended-spectrum β-lactamases (ESBLs), and plasmid-mediated quinolone resistance (PMQR) genes were screened by PCR. Bacterial isolates were typed by multilocus sequence typing (MLST).
Carbapenemase genes detection and sequencing showed that 18 (66.7%) isolates were
(NDM-1,
= 13; NDM-1 + OXA-48,
= 3; OXA-48,
= 1; OXA-232,
= 1), 6 (22.2%) were
(NDM-5,
= 3; OXA-181,
= 2; OXA-48,
= 1), and 3 (11.1%) were
(NDM-1,
= 1; OXA-181,
= 2). In addition the ESBL gene
was detected in 14
and 2
isolates, and the
was found in 1
isolate. Fifteen isolates were PMQR positive including
(
= 1),
(
= 5),
(
= 2), and
(
= 7). The MLST typing showed a diversity of sequence type (ST) clones including
ST410 (3), ST448 (2), and ST648;
ST78 and ST270; and
ST395 (2), ST309, ST23, ST35, ST1728, ST15, ST231, and ST1428.
This study reports the first description of OXA-48-like-producing Enterobacteriaceae and NDM-5 enzymes in
in Yemen.
We report the use of a rapid multiplex polymerase chain reaction (PCR) system in the microbiological diagnosis and the therapeutic management of a severe bacterial keratitis case.
During the ...management of a severe bacterial keratitis case, standard microbiological diagnostic methods were performed. At the same time, an additional ocular swab sampling from the cornea was performed and analyzed using two rapid multiplex PCR assays allowing the simultaneous detection of 29 different virus, yeast and bacteria genomes. Using combination of two rapid multiplex PCR systems, the microbiological diagnosis of a severe Pseudomonas aeruginosa induced keratitis was performed within 90 minutes after an ocular sampling. A rapid subsequent adaptation of local antibiotic treatment was performed allowing to the young patient to regain 6 months after her hospital admission a final visual acuity of 20/20 in her right eye.
The present case report suggests that the use of a rapid multiplex PCR strategy may result in a decrease of the mean hospital stage duration for severe infectious keratitis and in an improvement of the clinical outcome of severe keratitis infections. Nevertheless, additional prospective studies are needed to evaluate whether this innovative strategy may replace the current standard approach and optimize the therapeutic management of severe corneal infections.
In parallel, an additional corneal swab (eSwab®) was taken to perform two different Film Array® PCR systems (BioMérieux, Lyon, France). Due to the lack of a specific panel designed for infectious keratitis cases, corneal swabbing samples were tested using two previously reported diagnostic panels identified as "ME" for Meningitis-Encephalitis and "BCID" for Blood Culture Identification.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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