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Infection and Drug Resistance 2024To analyze the antibiotic resistance profile, virulence genes, and molecular typing of () strains isolated in skin and soft tissue infections at the First Affiliated...
OBJECTIVE
To analyze the antibiotic resistance profile, virulence genes, and molecular typing of () strains isolated in skin and soft tissue infections at the First Affiliated Hospital, Gannan Medical University, to better understand the molecular epidemiological characteristics of .
METHODS
In 2023, 65 strains were isolated from patients with skin and soft tissue infections. Strain identification and susceptibility tests were performed using VITEK 2 and gram-positive bacteria identification cards. DNA was extracted using a DNA extraction kit, and all genes were amplified using polymerase chain reaction. Multilocus sequence typing (MLST) was used for molecular typing.
RESULTS
In this study, of the 65 strains were tested for their susceptibility to 16 antibiotics, the highest resistance rate to penicillin G was 95.4%. None of the staphylococcal isolates showed resistance to ceftaroline, daptomycin, linezolid, tigecycline, teicoplanin, or vancomycin. was the most prevalent virulence gene (100%) in strains isolated in skin and soft tissue infections, followed by (98.5%). Statistical analyses showed that the resistance rates of methicillin-resistant isolates to various antibiotics were significantly higher than those of methicillin-susceptible isolates. Fifty sequence types (STs), including 44 new ones, were identified by MLST.
CONCLUSION
In this study, the high resistance rate to penicillin G and the high carrying rate of virulence gene and of S.aureus were determine, and 44 new STs were identified, which may be associated with the geographical location of southern Jiangxi and local trends in antibiotic use. The study of the clonal lineage and evolutionary relationships of in these regions may help in understanding the molecular epidemiology and provide the experimental basis for pathogenic bacteria prevention and treatment.
PubMed: 38933775
DOI: 10.2147/IDR.S465951 -
Journal of Agricultural and Food... Jun 2024Antibiotic residues may be present in fruit products from trees that were treated to combat bacterial diseases such as citrus greening or blight. A liquid...
Antibiotic residues may be present in fruit products from trees that were treated to combat bacterial diseases such as citrus greening or blight. A liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method was developed for the simultaneous determination and identification of streptomycin, kasugamycin, penicillin, and oxytetracycline residues in fruit. Samples were extracted with acidic methanol and separation was optimized for a hydrophilic interaction LC column. A Q-Exactive HRMS instrument was used to obtain product ion spectra for analyte identification. Quantitation was performed with matrix-extracted calibration curves and internal standard correction. The method was tested on many different types of fruit. In general, fortified samples demonstrated acceptable recoveries (82-116%) and reproducibility (<15% RSD). Method detection limits for these analytes were well below the established US EPA tolerance levels. It was also possible to analyze the fruit extracts prepared using this method for additional chemical contaminants using LC-HRMS.
PubMed: 38932744
DOI: 10.1021/acs.jafc.4c01792 -
Antibiotics (Basel, Switzerland) May 2024Staphylococcal scalded skin syndrome (SSSS) is a rare, toxin-mediated, desquamating bacterial infectious dermatosis. So far, data from Southwestern China is scarce. This...
Staphylococcal scalded skin syndrome (SSSS) is a rare, toxin-mediated, desquamating bacterial infectious dermatosis. So far, data from Southwestern China is scarce. This study aimed to investigate the clinical characteristics of SSSS patients in our hospital, the relative proportion of methicillin-resistant (MRSA) in skin and soft tissue secretions, and the drug sensitivity of to better assist dermatologists in the diagnosis and treatment of SSSS. We reviewed the demographic characteristics, clinical manifestations, treatment regimens, therapeutic efficacy, laboratory test results, drug sensitivity, and outcome data of 79 SSSS patients from January 2012 to December 2021. Statistical analysis was performed using tests and chi-square tests. Among the 79 SSSS patients, MRSA was detected in 35 (44.3%) isolates: 34 community-acquired (CA)-MRSA (97.1%) and 1 hospital-acquired (HA)-MRSA. The SSSS incidence increased annually from 2012 to 2014 and then decreased gradually after peaking in 2015. All the isolates were sensitive to vancomycin, tigecycline, linezolid, moxifloxacin, levofloxacin, and ciprofloxacin; were completely resistant to penicillin; and had low sensitivity to clindamycin and erythromycin. Interestingly, the sensitivity of MRSA to tetracycline increased annually after 2015. The resistance rates to common drugs previously used to treat SSSS increased. These findings may accelerate diagnosis and improve empirical antibiotic use, suggesting that clinicians should prescribe drugs according to antimicrobial susceptibility.
PubMed: 38927182
DOI: 10.3390/antibiotics13060516 -
Antibiotics (Basel, Switzerland) May 2024(group B streptococci, GBS) is responsible for severe infections in both neonates and adults. Currently, empiric antimicrobial therapy for sepsis and meningitis is the...
(group B streptococci, GBS) is responsible for severe infections in both neonates and adults. Currently, empiric antimicrobial therapy for sepsis and meningitis is the combined use of penicillin and gentamicin due to the enhanced bactericidal activity. However, high-level gentamicin resistance (HLGR) abrogates the synergism. The rate of HLGR was investigated within a dataset of 433 GBS strains collected from cases of invasive disease in both adults and neonates as well as from pregnant carriers. GBS isolates (n = 20, 4.6%) presented with HLGR (gentamicin MIC breakpoint >1024 mg/L) that was differently diffused between strains from adults or neonates (5.2% vs. 2.8%). Notably, 70% of HLGR GBS strains (14 isolates) were serotype IV. Serotype IV HLGR-GBS isolates were susceptible to all antibiotics tested, exhibited the alpha-C/HvgA/PI-2b virulence string, and belonged to sequence type 1010 (clonal complex (CC) 452). The mobile element that harbored the HLGR (6')-(2)″ gene is a novel integrative and conjugative element (ICE) about 45 kb long, derived from GBS 515 ICE tRNA. The clonal expansion of this HLGR hypervirulent serotype IV GBS CC452 sublineage may pose a threat to the management of infections caused by this strain type.
PubMed: 38927158
DOI: 10.3390/antibiotics13060491 -
Nature Communications Jun 2024Most rod-shaped bacteria elongate by inserting new cell wall material into the inner surface of the cell sidewall. This is performed by class A penicillin binding...
Most rod-shaped bacteria elongate by inserting new cell wall material into the inner surface of the cell sidewall. This is performed by class A penicillin binding proteins (PBPs) and a highly conserved protein complex, the elongasome, which moves processively around the cell circumference and inserts long glycan strands that act as barrel-hoop-like reinforcing structures, thereby giving rise to a rod-shaped cell. However, it remains unclear how elongasome synthesis dynamics and termination events are regulated to determine the length of these critical cell-reinforcing structures. To address this, we developed a method to track individual elongasome complexes around the entire circumference of Bacillus subtilis cells for minutes-long periods using single-molecule fluorescence microscopy. We found that the B. subtilis elongasome is highly processive and that processive synthesis events are frequently terminated by rapid reversal or extended pauses. We found that cellular levels of RodA regulate elongasome processivity, reversal and pausing. Our single-molecule data, together with stochastic simulations, show that elongasome dynamics and processivity are regulated by molecular motor tug-of-war competition between several, likely two, oppositely oriented peptidoglycan synthesis complexes associated with the MreB filament. Altogether these results demonstrate that molecular motor tug-of-war is a key regulator of elongasome dynamics in B. subtilis, which likely also regulates the cell shape via modulation of elongasome processivity.
Topics: Bacillus subtilis; Cell Wall; Bacterial Proteins; Penicillin-Binding Proteins; Peptidoglycan; Microscopy, Fluorescence; Single Molecule Imaging; Molecular Motor Proteins
PubMed: 38926336
DOI: 10.1038/s41467-024-49785-x -
Clinical Microbiology and Infection :... Jun 2024To estimate risk factors for AKI and the effect of AKI on mortality in Staphylococcus aureus bacteremia, while taking into account recurrent AKI episodes, competing...
OBJECTIVES
To estimate risk factors for AKI and the effect of AKI on mortality in Staphylococcus aureus bacteremia, while taking into account recurrent AKI episodes, competing risks, time-varying variables and time-varying effects.
METHODS
We performed an unplanned analysis using data from a multicenter cohort study of patients with SAB. Primary outcome was cumulative incidence of AKI, according to KDIGO definitions.
RESULTS
We included 453 patients in this study of whom 194 (43%) patients experienced one or more AKI episodes. Age (HR 1.013, 95% CI 1.001 - 1.024), Charlson comorbidity index (HR 1.07, 95% CI 1.01 - 1.14), prior chronic kidney disease (HR 1.76, 95% CI 1.28 - 2.42), septic shock (HR 3.28, 95% CI 2.31 - 4.66), persistent bacteremia (HR 1.53, 95% CI 1.08 - 2.17) and vancomycin therapy (HR 1.80, 95% CI 1.05 - 3.09) were independently associated with AKI, but flucloxacillin, cefazolin, rifampicin and aminoglycoside therapy were not. After adjustment for confounders and immortal time bias, AKI was associated with an increased risk of 90-day mortality (HR 4.26, 95% CI 2.91 - 6.23).
CONCLUSIONS
Incidence of AKI in SAB is high and a substantial proportion of patients develops recurrent episodes of AKI after recovery. AKI is specifically linked to the use of vancomycin and not to anti-staphylococcal penicillins. Clinical outcome of patients with SAB complicated by AKI is worse than previously estimated.
PubMed: 38925460
DOI: 10.1016/j.cmi.2024.06.017 -
International Journal of Antimicrobial... Jun 2024Herein, we investigated decreased susceptibility (DS; MICs 0.25-4 mg/L) and resistance (R; MICs >4 mg/L) to aztreonam-avibactam (ATM-AVI). Contemporary non-replicate...
Herein, we investigated decreased susceptibility (DS; MICs 0.25-4 mg/L) and resistance (R; MICs >4 mg/L) to aztreonam-avibactam (ATM-AVI). Contemporary non-replicate clinical isolates of carbapenemase-producing Escherichia coli (n=90) (CP-EC) and ESBL-producing E. coli (n=12) (EP-EC) was used. CP-EC belonged to 25 distinct sequence types (STs) and all EP-EC belonged to ST405. All strains were isolated through 2019-2022 at the Karolinska University Laboratory, Stockholm, Sweden. ATM-AVI MICs were determined with broth microdilution and the EUCAST epidemiological cutoff value of 0.125 mg/L was used to define the wildtype (WT). Whole genome sequences (Illumina) were analyzed for detecting of resistance determinants among WT vs non-WT isolates. Among 102 isolates, 40 (39%) and 62 (61%) were WT and non-WT respectively. Among non-WT isolates 20 were R and 42 were DS. Resistance was observed among 14/47 NDM-producers, 5/43 OXA-48 group producers, and 1/12 EP-EC. DS was observed among 29/47 NDM, 13/43 OXA-48 group, and 3/12 EP-EC. Resistant isolates predominantly belonged to ST405 followed by STs 410, 361, 167, 617, and 1284. Presence of PBP3 inserts (YRIK/YRIN) were observed in 20/20 and presence of CMY-42 in 5/20 resistant isolates. Several mutations in the ftsI (encoding PBP3) and regulatory genes of outer membrane proteins (OmpC and OmpF) and efflux pumps (AcrAB-TolC) were detected. A ≥2-fold reduction in MICs were observed among 20/20 vs 7/20 isolates tested in the presence of the membrane permeabilizer PMBN and efflux inhibitor PAβN, respectively. In conclusion, resistance to ATM-AVI is a result of interplay of various determinants, including target alterations, deactivating enzymes, and decreased permeability.
PubMed: 38925228
DOI: 10.1016/j.ijantimicag.2024.107256 -
PloS One 2024Antibiotic persistence is a phenomenon, where a small fraction of a bacterial population expresses a phenotypic variation that allows them to survive antibiotic...
Antibiotic persistence is a phenomenon, where a small fraction of a bacterial population expresses a phenotypic variation that allows them to survive antibiotic treatment, which is lethal to the rest of the population. These cells are called persisters cells, and their occurrence has been associated with recurrent disease. Streptococcus agalactiae is a human pathobiont, able to cause invasive infections, and recurrent infections have been reported to occur in both newborns and adults. In this study, we demonstrated that S. agalactiae NEM316 can form persister cells when exposed to antibiotics from different classes. The frequency of persister cell formation was dependent on bacterial growth phase and the class of antibiotics. The ability to form persister cells in response to penicillin was shown to be a general trait among different clinical S. agalactiae isolates, independent of sero- and sequence-type. Taken together, this study shows the existence of antibiotic tolerant S. agalactiae persister cells, which may explain why this bacterial species frequently persists after treatment of invasive infection and can be associated with recurrent disease.
Topics: Streptococcus agalactiae; Anti-Bacterial Agents; Humans; Microbial Sensitivity Tests; Streptococcal Infections; Drug Resistance, Bacterial; Penicillins
PubMed: 38924011
DOI: 10.1371/journal.pone.0303271 -
Inorganic Chemistry Jun 2024Procedures for the preparation of transition metal complexes having intact bicyclic cepham or penam systems as ligands have been developed. Starting from readily...
Procedures for the preparation of transition metal complexes having intact bicyclic cepham or penam systems as ligands have been developed. Starting from readily available 4-azido-2-azetidinones, a synthetic approach has been tuned using a copper-catalyzed azide-alkyne cycloaddition between 3-azido-2-azetinones and alkynes, followed by methylation and transmetalation to Au(I) and Ir(III) complexes from the mesoionic carbene Ag(I) complexes. This methodology was applied to 6-azido penam and 7-azido cepham derivatives to build 6-(1,2,3-triazolyl)penam and 7-(1,2,3-triazolyl)cepham proligands, which upon methylation and metalation with Au(I) and Ir(III) complexes yielded products derived from the coordination of the metal to the penam C and cepham C positions, preserving intact the bicyclic structure of the penicillin and cephalosporin scaffolds. The crystal structure of complex , which has an Ir atom directly bonded to the intact penicillin bicycle, was determined by X-ray diffraction. This is the first structural report of a penicillin-transition-metal complex having the bicyclic system of these antibiotics intact. The selectivity of the coordination processes was interpreted using DFT calculations.
PubMed: 38923955
DOI: 10.1021/acs.inorgchem.4c01548 -
Journal of Periodontology Jun 2024The aim of this study was to evaluate the incidence of preloading crestal bone loss (PLCBL) and to identify the patient-related and implant-related factors associated...
BACKGROUND
The aim of this study was to evaluate the incidence of preloading crestal bone loss (PLCBL) and to identify the patient-related and implant-related factors associated with PLCBL.
METHODS
This retrospective cohort examined the dental records of patients who received at least one dental implant. PLCBL was defined as a reduction ⩾0.5 mm and severe PLCBL (primary variable) as a reduction ⩾1.5 mm in mesial and/or distal bone level, measured from the day of implant placement to uncovering or abutment installation/crown delivery. The incidence of PLCBL and patient and implant variables were recorded. Bivariate analysis and binary logistic regression identified factors associated with PLCBL ⩾0.5 mm and ⩾1.5 mm.
RESULTS
A total of 746 dental implants placed in 361 patients from January 2011 to July 2021 was included in the analyses. Of the implants assessed, 24.4% (n = 182) exhibited PLCBL ⩾ 0.5 mm and 10.5% (n = 78) presented severe PLCBL (i.e., ⩾1.5 mm). Males (odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.11-3.07), patients with diabetes (OR = 3.33, 95% CI = 1.73-6.42), and those allergic to penicillin (OR = 3.13, 95% CI = 1.57-6.22) were more likely to experience severe PLCBL (p < 0.05). Implants placed in the anterior area (OR = 2.08, 95% CI = 1.16-3.73), with bone-level platform-abutment connection (OR = 4.73, 95% CI = 1.94-11.49) and inserted supracrestally (OR = 3.77, 95% CI = 1.84-7.72), presented a greater risk of developing severe PLCBL (p < 0.05). Implants placed in a previously grafted area presented a lower likelihood of developing severe PLCBL (OR = 0.489, 95% CI = 0.28-0.84).
CONCLUSION
The incidence of PLCBL ⩾ 0.5 mm and ⩾1.5 mm was 24.4% and 10.5%, respectively. Male sex, diabetes, allergy to penicillin, anterior location, bone-level platform-abutment connection, and supracrestal implant placement are potential risk factors for severe PLCBL. A previously grafted area is a potential protective factor.
PubMed: 38923568
DOI: 10.1002/JPER.24-0028