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Journal of Ophthalmic Inflammation and... Feb 2024To describe a puzzling case of endophthalmitis caused by three unusual bacteria after intravitreal injection, its outcome, and underlying questions.
PURPOSE
To describe a puzzling case of endophthalmitis caused by three unusual bacteria after intravitreal injection, its outcome, and underlying questions.
FINDINGS
A 70-year-old female patient was diagnosed with acute endophthalmitis following intravitreal aflibercept injection for age-related macular degeneration. A standard tap and inject procedure was performed. Microbiological analyses on the anterior chamber and vitreous samples yielded the presence of three non-fermenting Gram-negative rods: Pseudomonas stutzeri, Stenotrophomonas maltophilia, and Ochrobactrum anthropi. The outcome was favorable after intravitreal injections of vancomycin and ceftazidime, with an almost complete recovery of the visual acuity to its baseline level. No potential source of infection was identified.
CONCLUSION
Endophthalmitis following intravitreal injection can be caused by a wide variety of bacteria, including some rare Gram-negative species. They can sometimes co-exist in a single patient, but their virulence may vary greatly. Due to the variable antibiotic susceptibility and frequent multiresistance associated with non-fermenting Gram-negative rods, a prompt microbiological approach is required. Favorable outcome can be achieved with standard management.
PubMed: 38334879
DOI: 10.1186/s12348-023-00376-9 -
European Journal of Microbiology &... May 2024Extensive use of carbapenems may lead to selection pressure for Stenotrophomonas maltophilia (SM) in hospital environments. The aim of our study was to assess the...
Extensive use of carbapenems may lead to selection pressure for Stenotrophomonas maltophilia (SM) in hospital environments. The aim of our study was to assess the possible association between systemic antibiotic use and the incidence of SM. A retrospective, observational study was carried out in a tertiary-care hospital in Hungary, between January 1st 2010 and December 31st 2019. Incidence-density for SM and SM resistant to trimethoprim-sulfamethoxazole (SXT) was standardized for 1000 patient-days, while systemic antibiotic use was expressed as defined daily doses (DDDs) per 100 patient-days. Mean incidence density for SM infections was 0.42/1000 patient-days; 11.08% were were resistant to SXT, the mean incidence density for SXT-resistant SM was 0.047/1000 patient-days. Consumption rate for colistin, glycopeptides and carbapenems increased by 258.82, 278.94 and 372.72% from 2010 to 2019, respectively. Strong and significant positive correlations were observed with the consumption of carbapenems (r: 0.8759; P < 0.001 and r: 0.8968; P < 0.001), SXT (r: 0.7552; P = 0.011 and r: 0.7004; P = 0.024), and glycopeptides (r: 0.7542; P = 0.012 and r: 0.8138; P < 0.001) with SM and SXT-resistant SM incidence-density/1000 patient-days, respectively. Implementation of institutional carbapenem-sparing strategies are critical in preserving these life-saving drugs, and may affect the microbial spectrum of infections in clinical settings.
PubMed: 38441614
DOI: 10.1556/1886.2024.00022 -
Journal of Clinical Microbiology Oct 2023Whole-genome sequencing (WGS) provides greater resolution than other molecular epidemiology strategies and is emerging as a new gold standard approach for microbial...
Whole-genome sequencing (WGS) provides greater resolution than other molecular epidemiology strategies and is emerging as a new gold standard approach for microbial strain typing. The Bruker IR Biotyper is designed as a screening tool to identify bacterial isolates that require WGS to establish accurate relationships, but its performance and utility in nosocomial outbreak investigations have not been thoroughly investigated. Here, we evaluated the IR Biotyper by retrospectively examining isolates tested by WGS during investigations of potential nosocomial transmission events or outbreaks. Ninety-eight clinical isolates from 14 different outbreak investigations were examined: three collections of ( = 2, = 9, = 5 isolates in each collection), one of ( = 16), two of ( = 2 and = 5), two of ( = 9 and = 7), five of ( = 8, = 4, = 3, = 3, = 17), and one of ( = 8). Linear regression demonstrated a weak, positive correlation between the number of pairwise genome-wide single-nucleotide polymorphisms (SNPs) and IR Biotyper spectral distance values for Gram-positive ( = 0.43, ≤ 0.0001), Gram-negative ( = 0.1554, = 0.0639), and all organisms combined ( = 0.342, ≤ 0.0001). Overall, the IR Biotyper had a positive predictive value (PPV) of 55.81% for identifying strains that were closely related by genomic identity, but a negative predictive value (NPV) of 86.79% for identifying unrelated isolates. When experimentally adjusted cut-offs were applied to , and the PPV was 62% for identifying strains that were closely related and the NPV was 100% for identifying unrelated isolates. Implementation of the IR Biotyper as a screening tool in this cohort would have reduced the number of Gram-negative isolates requiring further WGS analysis by 50% and would reduce the number of isolates needing WGS resolution by 48%.
Topics: Humans; Escherichia coli; Cross Infection; Retrospective Studies; Spectroscopy, Fourier Transform Infrared; Fourier Analysis; Staphylococcus aureus; Genome, Bacterial; Disease Outbreaks
PubMed: 37787542
DOI: 10.1128/jcm.00347-23 -
Pediatrics and Neonatology Mar 2024Stenotrophomonas maltophilia is an emerging multi-drug resistant, opportunistic pathogen in the neonatal intensive care unit (NICU). In this study, we aimed to assess...
OBJECTIVE
Stenotrophomonas maltophilia is an emerging multi-drug resistant, opportunistic pathogen in the neonatal intensive care unit (NICU). In this study, we aimed to assess the incidence, clinical features, antibiotic susceptibility, and treatment options of S. maltophilia infection among the healthcare-associated infections (HAIs) in the neonatal unit.
METHODS
In this study, the patients who were hospitalized in the NICU between January 2020 and December 2021 with S. maltophilia isolated from clinical samples were included. Demographic, clinic features, and microbiological findings of the patients were retrospectively evaluated by using the medical records. The samples (lower respiratory tract, urine, peritoneal fluid) were first examined microscopically by gram preparation and cultured. Antibiotic susceptibility tests were performed according to the recommendations of The European Committee on Antimicrobial Susceptibility Testing (EUCAST) for TMP-SMX.
RESULTS
S. maltophilia was isolated in 38 clinical samples of the 20 patients who were hospitalized at the NICU between January 2020 and December 2021. A total of 40 % (n = 8) of samples from different patients were accepted as colonization. Ventilator-associated pneumonia was determined in 55 % (n = 11), and urinary tract infection in 5 % (n = 1). S. maltophilia-associated bacteremia was not detected in any of the cases. The TMP-SMX susceptibilities of the strains were as it follows: 3 (15 %) were resistant (R), 7 (28 %) were susceptible (S), and 10 (47 %) were susceptible-increased exposure (I). Three of these patients were given dual antibiotics therapy (levofloxacin plus TMP-SMX) and nine of them were given only TMP-SMX. The most common hospital-acquired infectious agents are Gram negative microorganisms (51 %), followed by coagulase negative staphylococci (CNS), Staphylococcus aureus (24 %) and S. maltophilia (24 %).
CONCLUSION
Increasing TMP-SMX resistance and specific drug and dosage-related problems in the neonatal unit are important problems in treatment management.
Topics: Infant, Newborn; Humans; Trimethoprim, Sulfamethoxazole Drug Combination; Intensive Care Units, Neonatal; Stenotrophomonas maltophilia; Retrospective Studies; Turkey; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37919104
DOI: 10.1016/j.pedneo.2023.04.019 -
Frontiers in Cellular and Infection... 2024is a prominent genus owing to its dual nature. Species of this genus have many applications in industry and agriculture as plant growth-promoting rhizobacteria and...
INTRODUCTION
is a prominent genus owing to its dual nature. Species of this genus have many applications in industry and agriculture as plant growth-promoting rhizobacteria and microbial biological control agents, whereas species such as are considered one of the leading gram-negative multi-drug-resistant bacterial pathogens because of their high contribution to the increase in crude mortality and significant clinical challenge. Pathogenic species and most clinical isolates belong to the complex (SMc). However, a strain highly homologous to was isolated from a patient with pulmonary tuberculosis (TB), which aroused our interest, as belongs to a relatively distant clade from SMc and there have been no human association reports.
METHODS
The pathogenicity, immunological and biochemical characteristics of 610A2 were systematically evaluated.
RESULTS
610A2 is a new species of genus , which is named as sp. nov. for its obvious brown water-soluble pigment. 610A2 is pathogenic and caused significant weight loss, pulmonary congestion, and blood transmission in mice because it has multiple virulence factors, haemolysis, and strong biofilm formation abilities. In addition, the cytokine response induced by this strain was similar to that observed in patients with TB, and the strain was resistant to half of the anti-TB drugs.
CONCLUSIONS
The pathogenicity of 610A2 may not be weaker than that of . Its isolation extended the opportunistic pathogenic species to all 3 major clades of the genus , indicating that the clinical importance of species of other than and potential risks to biological safety associated with the use of require more attention.
Topics: Stenotrophomonas; Animals; Phylogeny; Gram-Negative Bacterial Infections; Biofilms; Mice; Virulence Factors; RNA, Ribosomal, 16S; Humans; DNA, Bacterial; Sequence Analysis, DNA; Disease Models, Animal; Hemolysis; Bacterial Typing Techniques
PubMed: 38903940
DOI: 10.3389/fcimb.2024.1410385 -
Immunity, Inflammation and Disease Jul 2023To investigate the distribution of bacterial pathogens of lower respiratory tract infection (LRTI) in hospitalized elderly patients during the COVID-19 epidemic and to...
BACKGROUND
To investigate the distribution of bacterial pathogens of lower respiratory tract infection (LRTI) in hospitalized elderly patients during the COVID-19 epidemic and to explore the influence of COVID-19 on the distribution of bacterial pathogens, to provide guidance for clinical diagnosis.
METHODS
Specimens of sputum from elderly LRTIs patients at Fuding Hospital of China were consecutively collected from October 2022 to January 2023. Cultures and identification were done, and RT-PCR was employed to detect SARS-Cov-2 nucleic acid.
RESULTS
A total of 195 isolates were characterized in 163 sputum samples of consecutive hospitalized elderly patients, of which 11.3% were Gram-positive bacteria and 88.7% were Gram-negative. The top of frequently isolated pathogens was Klebsiella pneumonia (30.3%), Pseudomonas aeruginosa (19.0%), Acinetobacter baumannii (12.8%), Stenotrophomonas maltophili, (7.7%), Escherichia coli (7.2%). According to the results of novel coronavirus nucleic acid detection, the 163 patients were divided into COVID-19 group and non-COVID control (CNT) group. The comparison of bacterial distribution between the groups revealed that Stenotrophomonas maltophilia was lower in the COVID-19 than in the CNT group, while A. baumannii was higher in the COVID-19 group, and the difference was statistically significant (p < .05).
CONCLUSION
The major bacteria identified in sputum culture of hospitalized elderly patients were K. pneumonia, P. aeruginosa, A. baumannii, S. maltophilia, and E. coli. Furthermore, the distribution of S. maltophilia and A. baumannii between the COVID-19 and CNT groups was found to be significantly different (p < .05), while there were no significant differences in the distribution of other bacteria.
Topics: Humans; Aged; Anti-Bacterial Agents; Escherichia coli; COVID-19; SARS-CoV-2; Bacteria; Respiratory Tract Infections; Respiratory System
PubMed: 37506149
DOI: 10.1002/iid3.931 -
Pathogens (Basel, Switzerland) Dec 2023is a multidrug-resistant Gram-negative bacillus associated with nosocomial infections in intensive care units, and nowadays, its acquired resistance to...
is a multidrug-resistant Gram-negative bacillus associated with nosocomial infections in intensive care units, and nowadays, its acquired resistance to trimethoprim-sulfamethoxazole (SXT) by genes within class 1 integrons is a worldwide health problem. Biofilm and motility are two of the major virulence factors in this bacterium and are auto-induced by the diffusible signal factor (DSF). In recent studies, retinoids have been used to inhibit (Quorum Quenching) these virulence factors and for their antimicrobial effect. The aim was to reduce biofilm formation and motility with retinoic acid (RA) in SXT-resistant strains. Eleven SXT-resistant strains and two SXT-susceptible strains were tested for biofilm formation/reduction and planktonic/sessile cell viability with RA and SXT-MIC/RA; motility (twitching, swimming, swarming) was measured with/without RA; and MLST typing was determined. The biofilm formation of the strains was classified as follows: 15.38% (2/13) as low, 61.54% (8/13) as moderate, and 23.08% (3/13) as high. It was significantly reduced with RA and SXT-MIC/RA ( < 0.05); cell viability was not significantly reduced with RA ( > 0.05), but it was with SXT-MIC/RA ( < 0.05); and swimming ( < 0.05) and swarming ( < 0.05) decreased significantly. MLST typing showed the first and novel strains of Mexican registered in PubMLST (ST479-485, ST497, ST23, ST122, ST175, ST212, and ST300). In conclusion, RA reduced biofilm formation and motility without affecting cell viability; furthermore, antimicrobial synergism with SXT-MIC/RA in different and novel STs of was observed.
PubMed: 38133331
DOI: 10.3390/pathogens12121448 -
Journal of Medical Case Reports Mar 2024Stenotrophomonas maltophilia is a gram-negative bacteria known for causing opportunistic and nosocomial infections in humans. S. maltophilia is an emerging pathogen of...
BACKGROUND
Stenotrophomonas maltophilia is a gram-negative bacteria known for causing opportunistic and nosocomial infections in humans. S. maltophilia is an emerging pathogen of concern due to it's increasing prevalence, diverse disease spectrum, intrinsic multi-drug resistance and high mortality rates in immunocompromised individuals. S. maltophilia is a rare cause of neonatal sepsis associated with significant morbidity and mortality. The bacterium's multi-drug resistance poses a considerable challenge for treatment, with various mechanisms contributing to its resistance.
CASE PRESENTATION
We report a case involving a 40-h-old male African neonate who exhibited symptoms of neonatal sepsis. The blood culture revealed Stenotrophomonas maltophilia, which was sensitive to ciprofloxacin and gentamicin but resistant to other antibiotics. Lumbar puncture for CSF could not be done because the father declined. We treated the newborn with the empirical first-line antibiotics as per the national guideline intravenous ampicillin and gentamicin for six days, and the child recovered fully with a repeated negative blood culture.
CONCLUSIONS
This report describes a neonatal sepsis case caused by S. maltophilia, a multi-drug resistant bacteria and a rare cause of neonatal sepsis. We report that early detection of the bacterial and antimicrobial management based on local antibiogram data may be essential for successful patient's management.
Topics: Child; Infant, Newborn; Male; Humans; Stenotrophomonas maltophilia; Neonatal Sepsis; Gram-Negative Bacterial Infections; Anti-Bacterial Agents; Gentamicins
PubMed: 38523318
DOI: 10.1186/s13256-024-04479-2 -
Revista Argentina de Microbiologia 2023
False positive NDM and OXA-48 results of the lateral flow carbapenem-resistant K.N.I.V.O. Detection K-set in Stenotrophomonas maltophilia: Time for official performance evaluation of LFAs?
Topics: Carbapenems; Stenotrophomonas maltophilia; beta-Lactamases; Bacterial Proteins; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37385832
DOI: 10.1016/j.ram.2023.04.005 -
Microbiology Spectrum Aug 2023Outer membrane protein A (OmpA) is the most abundant porin in bacterial outer membranes. KJΔOmpA, an C-terminal in-frame deletion mutant of Stenotrophomonas...
Outer membrane protein A (OmpA) is the most abundant porin in bacterial outer membranes. KJΔOmpA, an C-terminal in-frame deletion mutant of Stenotrophomonas maltophilia KJ, exhibits pleiotropic defects, including decreased tolerance to menadione (MD)-mediated oxidative stress. Here, we elucidated the underlying mechanism of the decreased MD tolerance mediated by Δ. The transcriptomes of wild-type S. maltophilia and the KJΔOmpA mutant strain were compared, focusing on 27 genes known to be associated with oxidative stress alleviation; however, no significant differences were identified. was the most downregulated gene in KJΔOmpA. KJΔOmpA complementation with the chromosomally integrated gene restored MD tolerance to the wild-type level, indicating the role of OmpO in MD tolerance. To further clarify the possible regulatory circuit involved in defects and downregulation, σ factor expression levels were examined based on the transcriptome results. The expression levels of three σ factors were significantly different (downregulated levels of and upregulated levels of and ) in KJΔOmpA. Next, the involvement of the three σ factors in the Δ-mediated decrease in MD tolerance was evaluated using mutant strains and complementation assays. downregulation and upregulation contributed to the Δ-mediated decrease in MD tolerance. OmpA C-terminal domain loss induced an envelope stress response. Activated σ decreased and expression levels, in turn decreasing swimming motility and oxidative stress tolerance. Finally, we revealed both the Δ-- regulatory circuit and - cross regulation. The cell envelope is a morphological hallmark of Gram-negative bacteria. It consists of an inner membrane, a peptidoglycan layer, and an outer membrane. OmpA, an outer membrane protein, is characterized by an N-terminal β-barrel domain that is embedded in the outer membrane and a C-terminal globular domain that is suspended in the periplasmic space and connected to the peptidoglycan layer. OmpA is crucial for the maintenance of envelope integrity. Stress resulting from the destruction of envelope integrity is sensed by extracytoplasmic function (ECF) σ factors, which induce responses to various stressors. In this study, we revealed that loss of the OmpA-peptidoglycan (PG) interaction causes peptidoglycan and envelope stress while simultaneously upregulating σ and σ expression levels. The outcomes of σ and σ activation are different and are linked to β-lactam and oxidative stress tolerance, respectively. These findings establish that outer membrane proteins (OMPs) play a critical role in envelope integrity and stress tolerance.
Topics: Stenotrophomonas maltophilia; Regulon; Peptidoglycan; Sigma Factor; Oxidative Stress; Bacterial Proteins; Gene Expression Regulation, Bacterial
PubMed: 37284772
DOI: 10.1128/spectrum.01080-23