Disc diffusion is a reliable, accurate and cost-efficient procedure for antimicrobial susceptibility testing (AST) but requires long (18-24 h) incubation times. Reading of disc diffusion after short ...incubation times (6-8 h) by automated systems is feasible but should be categorized with time-adapted breakpoints to reduce errors.
This study systematically compared early readings (6 and 8 h) of disc diffusion using an automated system with that of the standard 18 h EUCAST method. Time-adapted tentative breakpoints were proposed to discriminate susceptible from resistant isolates and areas of technical uncertainty were defined to minimize the risk of errors.
A total of 1106 Enterobacterales isolates with a wide variety of resistance mechanisms and resistance profiles were included. All isolates were analysed for susceptibility to amoxicillin/clavulanic acid, ceftriaxone, cefepime, meropenem, ciprofloxacin and gentamicin using the automated WASPLabTM system. Part of the collection (515 isolates) was also analysed for susceptibility to an additional 10 antibiotics.
Separation between WT and non-WT populations was poorer at early incubation times than following standard incubation. Editing of rapid automated AST results after 6 and 8 h incubation with time-adapted breakpoints resulted in 84.0% and 88.5% interpretable results with assignment to the resistant or susceptible category. Major error and very major error rates for the 6 h readings were only 0.4% and 0.3%, virtually identical to those of 18 h AST reading.
Time-adapted clinical breakpoints in disc diffusion testing for Enterobacterales allow for accurate automated AST interpretation after shortened incubation times for a large number of antibiotics, with the additional possibility of subsequent confirmation after 18 h incubation.
Aspergillus spp. of section Usti (A. ustus) represent a rare cause of invasive aspergillosis (IA). This multicenter study describes the epidemiology and outcome of A. ustus infections.
Patients with ...A. ustus isolated from any clinical specimen were retrospectively identified in 22 hospitals from 8 countries. When available, isolates were sent for species identification (BenA/CaM sequencing) and antifungal susceptibility testing. Additional cases were identified by review of the literature. Cases were classified as proven/probable IA or no infection, according to standard international criteria.
Clinical report forms were obtained for 90 patients, of whom 27 had proven/probable IA. An additional 45 cases were identified from literature review for a total of 72 cases of proven/probable IA. Hematopoietic cell and solid-organ transplant recipients accounted for 47% and 33% cases, respectively. Only 8% patients were neutropenic at time of diagnosis. Ongoing antimold prophylaxis was present in 47% of cases. Pulmonary IA represented 67% of cases. Primary or secondary extrapulmonary sites of infection were observed in 46% of cases, with skin being affected in 28% of cases. Multiple antifungal drugs were used (consecutively or in combination) in 67% of cases. The 24-week mortality rate was 58%. A. calidoustus was the most frequent causal agent. Minimal inhibitory concentrations encompassing 90% isolates (MIC90) were 1, 8, >16, and 4 µg/mL for amphotericin B, voriconazole, posaconazole, and isavuconazole, respectively.
Aspergillus ustus IA mainly occurred in nonneutropenic transplant patients and was frequently associated with extrapulmonary sites of infection. Mortality rate was high and optimal antifungal therapy remains to be defined.
Infections with Scedosporium spp. are emerging in the past two decades and are associated with a high mortality rate. Microbiological detection can be associated with either colonization or ...infection. Evolution from colonization into infection is difficult to predict and clinical management upon microbiological detection is complex. Microbiological samples from 2015 to 2021 were retrospectively analyzed in a single tertiary care center. Classification into colonization or infection was performed upon first microbiological detection. Clinical evolution was observed until July 2023. Further diagnostic procedures after initial detection were analyzed. Among 38 patients with microbiological detection of Scedosporium spp., 10 were diagnosed with an infection at the initial detection and two progressed from colonization to infection during the observation time. The main sites of infection were lung (5/12; 41.6%) followed by ocular sites (4/12; 33.3%). Imaging, bronchoscopy or biopsies upon detection were performed in a minority of patients. Overall mortality rate was similar in both groups initially classified as colonization or infection 30.7% and 33.3%, respectively (P = 1.0). In all patients where surgical debridement of site of infection was performed (5/12; 42%); no death was observed. Although death occurred more often in the group without eradication (3/4; 75%) compared with the group with successful eradication (1/8; 12.5%), statistical significance could not be reached (P = 0.053). As therapeutic management directly impacts patients' outcome, a multidisciplinary approach upon microbiological detection of Scedosporium spp. should be encouraged. Data from larger cohorts are warranted in order to analyze contributing factors favoring the evolution from colonization into infection.
•Photodynamic therapy (PDT) is a potent treatment to improve skin antisepsis.•Immediately after PDT, complete skin sterilization is achieved.•The effects of PDT did not last after 7–21 days ...post-treatment.
Current standard skin antisepsis to prevent surgical site infections are ineffective to eradicate all skin-colonizing bacteria. Photodynamic therapy (PDT) has shown bactericidal effects in vitro, but no clinical study with improvements in skin antisepsis has been documented.
We investigated the effect of methyl aminolevulinate (MAL)-PDT versus no PDT for skin antisepsis treatment (povidone-iodine/alcohol) in the groin of 10 healthy participants. Skin swabs were taken at baseline, immediately after PDT, and after skin antisepsis treatment to cultivate bacteria. At day 7 and 21, bacterial cultures were repeated before and after antisepsis treatment without PDT. Skin biopsies were performed to examine the grade of inflammation.
Skin-colonizing bacteria were found in all 20 participants at baseline sampling. Immediately after MAL-PDT, skin was sterile in 7 (70%) participants before and in all 10 (100%) participants after skin antisepsis treatment. In contrast, we found skin-colonizing bacteria in 5 (50%) participants of the control group receiving only skin antisepsis. After 7 and 21 days, skin sterility was similar to the baseline. We observed slight perivascular inflammation with lymphocytes and eosinophils without changes in the histomorphology of eccrine or sebaceous glands in skin biopsies. PDT was generally well tolerated except for localized redness.
MAL-PDT with skin antisepsis treatment sterilized skin immediately after its use but did not maintain sterility 7–21 days post-treatment. Due to local side effects, further clinical studies with less intensive PDT conditions or other photosensitizers are needed before PDT is integrated into clinical practice.
Antibiotic-tolerant Staphylococcus aureus poses a great challenge to clinicians as well as to microbiological laboratories and is one reason for treatment failure. Antibiotic-tolerant strains survive ...transient antibiotic exposure despite being fully susceptible
. Thus, fast and reliable methods to detect tolerance in the routine microbiology laboratory are urgently required. We therefore evaluated the feasibility of the replica plating tolerance isolation system (REPTIS) to detect antibiotic tolerance in Staphylococcus aureus isolates derived directly from patients suffering from different types of infections and investigated possible connections to clinical presentations and patient characteristics. One hundred twenty-five S. aureus isolates were included. Replica plating of the original resistance testing plate was used to assess regrowth in the zones of inhibition, indicating antibiotic tolerance. Bacterial regrowth was assessed after 24 and 48 h of incubation, and an overall regrowth score (ORS) was assigned. Regrowth scores were compared to the clinical presentation. Bacterial regrowth was high for most antibiotics targeting protein synthesis and relatively low for antibiotics targeting other cellular functions such as DNA replication, transcription, and cell wall synthesis, with the exception of rifampin. Isolates with a blaZ penicillinase had lower regrowth in penicillin and ampicillin. Low ORSs were more prevalent among isolates recovered from patients with immunosuppression or methicillin-resistant S. aureus (MRSA) isolates. In conclusion, REPTIS is useful to detect antibiotic tolerance in clinical microbiological routine diagnostics. Further studies should evaluate the impact of rapid detection of antibiotic tolerance as a clinical decision-making tool for tailored antibiotic treatments.
Background
respiratory infections are transmitted by aerosol and droplets in close contact.AimWe investigated global
incidence after implementation of non-pharmaceutical interventions (NPIs) against ...COVID-19 in March 2020.MethodsWe surveyed
detections from laboratories and surveillance systems (national or regional) across the world from 1 April 2020 to 31 March 2021 and compared them with cases from corresponding months between 2017 and 2020. Macrolide-resistant
(MRMp) data were collected from 1 April 2017 to 31 March 2021.ResultsThirty-seven sites from 21 countries in Europe, Asia, America and Oceania submitted valid datasets (631,104 tests). Among the 30,617
detections, 62.39% were based on direct test methods (predominantly PCR), 34.24% on a combination of PCR and serology (no distinction between methods) and 3.37% on serology alone (only IgM considered). In all countries,
incidence by direct test methods declined significantly after implementation of NPIs with a mean of 1.69% (SD ± 3.30) compared with 8.61% (SD ± 10.62) in previous years (p < 0.01). Detection rates decreased with direct but not with indirect test methods (serology) (-93.51% vs + 18.08%; p < 0.01). Direct detections remained low worldwide throughout April 2020 to March 2021 despite widely differing lockdown or school closure periods. Seven sites (Europe, Asia and America) reported MRMp detections in one of 22 investigated cases in April 2020 to March 2021 and 176 of 762 (23.10%) in previous years (p = 0.04).ConclusionsThis comprehensive collection of
detections worldwide shows correlation between COVID-19 NPIs and significantly reduced detection numbers.
Background
To assess the effect of concomitant subgingival rinsing with 10% PVP‐iodine during subgingival instrumentation on the prevalence and magnitude of bacteraemia of oral origin.
Materials and ...Methods
Subgingival instrumentation was performed with water or PVP‐iodine rinse in patients with periodontitis. Prior to instrumentation, subjects gargled for 1 min with the allocated liquid. Pockets were then rinsed for 1 min and subgingivally instrumented with liquid‐cooled (water/PVP‐iodine) ultrasonic scalers (1 min). Two minutes later, a blood sample from the arm vein was drawn using a lysis centrifugation blood culture system for quantitative microbiological analysis. Non‐parametric statistical tests were performed to assess differences in the prevalence and extent of bacteraemia between groups.
Results
Of the 19 samples in each group, oral‐borne bacteraemia was detected in 10 of the control and 2 of the test samples. With an average of 3.0 1; 5 colony forming units, significantly less bacteria and bacteraemia were found in the test group compared to the controls (12.2 1; 46) (p = 0.003). Anaerobic bacteria were not found in the test group.
Conclusions
Bacteraemia after subgingival instrumentation with concomitant PVP‐iodine rinsing is reduced but not eliminated. Therefore, it might be recommended for patients at a high risk of endocarditis or infection of endoprostheses. However, preventive antibiotic treatment should not be omitted.
Purpose
Periprosthetic joint infections (PJIs) remain a challenging complication after shoulder arthroplasty. The antimicrobial peptide α-defensin has been proposed as a new synovial fluid biomarker ...in diagnosing PJIs. To date, only little data are available on the diagnostic accuracy of α-defensin in shoulder PJIs; thus, we aimed to evaluate its diagnostic value in a cohort of patients with a suspected shoulder PJI.
Methods
Between June 2016 and June 2018, we prospectively enrolled patients with a diagnostic shoulder aspiration due to painful shoulder arthroplasty or planned revision surgery. PJI diagnostics were performed according to the Musculoskeletal Infection Society (MSIS) criteria. All patients with an antibiotic therapy within two weeks before enrollment, insufficient amount of synovial aspirate, or bloody aspiration were excluded. α-Defensin was measured in the synovial fluid using the α-defensin lateral flow (ADLF) test (Synovasure®).
Results
Out of 60 patients, we could include 29 (59% female) patients with a mean age of 70 (range, 50–92) years. A shoulder PJI was detected in five cases (
Staphylococcus aureus
,
n
= 2;
Staphylococcus epidermidis
,
n
= 2;
Cutibacterium acnes
,
n
= 1). The ADLF test was positive in seven out of 29 cases. According to the MSIS criteria, the ADLF test was false-negative in two patients and false-positive in four patients, resulting in sensitivity, specificity, and positive and negative predictive value of 60%, 83%, 43%, and 91%, respectively. The overall accuracy was 79%.
Conclusion
The ALDF test does not appear to be useful in predicting shoulder PJIs but may be used as an additional diagnostic factor in rejecting these infections.
Abstract Background Our aim is to elucidate shifts in the bacterial spectrum colonising burn wounds and corresponding antibiotic susceptibilities during a 20-year study period. Methods ...Microbiological results from burn patients collected between 1986 and 2005 were analysed retrospectively. Results Staphylococcus aureus was isolated most frequently (20.8%), followed by Escherichia coli (13.9%), Pseudomonas aeruginosa (11.8%), coagulase-negative staphylococci (CNS) (10.9%), Enterococcus sp. (9.7%), Enterobacter cloacae (5.6%), Klebsiella pneumoniae (5%), Acinetobacter sp. (3.2%), Proteus mirabilis (2%) and Stenotrophomonas maltophilia (1.4%). Susceptibility of S. aureus to broad-spectrum substances such as ciprofloxacin or penicillinase-stable penicillins has waned, others such as cotrimoxazole or netilmicin remained effective. Not a single resistance against vancomycin was recorded. Increases in methicillin-resistant S. aureus (MRSA) were pronounced (3% in 1986–1997 (the first of the three study periods) to 16% in 1998–2001 and 13% in 2002–2005). Results for methicillin-resistant CNS (MRCNS) show an even greater increase. P. aeruginosa has shown increasing susceptibility against netilmicin (1986–1989: 84%, 2002–2005: 95%). Susceptibility of P. aeruginosa to ceftazidime has decreased markedly. S. maltophilia has shown clinically relevant susceptibility mainly against ciprofloxacin. Acinetobacter sp. have shown little susceptibility to most antibiotics. Imipenem or meropenem have been very reliable reserve antibiotics throughout the study period for the fermenting Enterobacteriaceae ( E. coli , K. pneumoniae , E. cloacae and P. mirabilis ), with susceptibilities of or near 100%. Conclusion In-depth knowledge of the bacteria causing infectious complications and of their antibiotic susceptibilities is a prerequisite for treating burn patients. Our study shows shifts in the microbial spectrum and their antibiogram, which mandate frequent reassessments.
In healthy preterm infants, the galactomannan enzyme-linked immunoassay shows a high rate of positive results and should not be used for the early diagnosis of invasive aspergillosis, particularly in ...the very preterm age group.
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