Antimicrobial Resistance and Molecular Characterization of Salmonella Rissen Isolated in China During 2008-2019.

Background: This study aimed to provide epidemiological features of Salmonella enterica serovar Rissen, determine antimicrobial susceptibility, virulence gene profiles, and describe the potential association of S. Rissen from different sources in China. Methods: During 2008-2019, a total of non-repetitive 228 S. Rissen isolates were collected from human, animals and environment in China. The antimicrobial susceptibility test, screening of antimicrobial and virulence genes by PCR, and pulsed-field gel electrophoresis (PFGE) were performed. Results: Among the 154 isolates from human, the majority of the cases (80.5%) occurred in summer, and S. Rissen was mainly detected in people aged 21-40 (37.7%) and 41-60 (28.6%) years old, and 74 non-human source S. Rissen strains were identified, with pork being the most common source. About 93.4% isolates were resistant to at least one of the 12 tested antimicrobial agents, and high frequencies of resistance were observed for tetracyclines (91.2%), trimethoprim-sulfamethoxazole (74.1%) and ampicillin (67.5%). A total of 171 (75%) isolates were resistant to at least three categories of antimicrobials, and the most common resistance profile was Tetracycline(s)-ß-Lactams-Sulfonamides. The resistance rates to chloramphenicol, quinolones and sulfafurazole were significantly higher in strains isolated from human compared to non-human source strains. Among these isolates, the ß-Lactams resistance was mainly associated with gene blaTEM (54.7%), sulfonamide resistance with sul2 (45.7%) and sul3 (54.3%), tetracycline resistance with tetA (81.3%). All the isolates harbored virulence genes hilA, sopB, sciN, stn and ssrB, and most of them harbored ssaQ (98.7%), mgtC (98.7%) and invA (98.2%). The majority (91.7%) of S. Rissen isolates showed high similarity (>80%) with each other in PFGE patterns and came from human, animals and environment. Conclusion: The high frequencies of multidrug resistance and probable clonal dissemination in this serovar call for the necessity of systematic surveillance on S. Rissen in China.

Risk factors for treatment failure in multidrug resistant tuberculosis in Tunisia: An analytic study.

INTRODUCTION-AIM: The emergence of multidrug resistant tuberculosis (MDR-TB) is a threat to global public health. The aim of our study was to determine risk factors for treatment failure in MDR-TB. METHODS: Retrospective study conducted between January 2000 and March 2019 including patients with MDR-TB. Characteristics of patients with therapeutic failure were compared to cured ones. Logistic regression analysis was used to identify risk factors for treatment failure. RESULTS: Our study included 140 patients aged of 42±13 years (18-80). Fifty-seven percent of patients had treatment success and 12% had treatment failure. In multivariate logistic regression analysis, treatment failure was associated with age over 45 years (OR=1.05; 95%CI, 1.024-7.736;p=0.014), primary education level and illiteracy (OR=5.022; 95%CI, 1.316-19.161;p=0,018), history of incarceration (OR=3.291; 95%CI, 1.291-21.083;p=0.016), undernutrition (OR=4.544; 95%CI, 2.304-54.231;p=0,027), extensive TB (OR=6.406; 95%CI, 1.761-23.922; p=0.038), initial high grade positive smears (OR=1.210; 95%CI, 1.187-32.657; p=0.045), positive smear culture at 90 days of treatment (OR=6.871, 95%CI, 3.824-23.541; p=0.003), poor adherence (OR=6.110; 95%CI, 2.740-12.450; p=0.021) and occurrence of psychiatric adverse events (OR=3.644 95%CI, 2.560- 27.268; p=0.041). CONCLUSION: Therapeutic education, nutritional and psychological support and close follow-up are strongly recommended to optimize the prognosis of MDR-TB.

Impact of mixed-infection rate of clarithromycin-susceptible and clarithromycin-resistant Helicobacter pylori strains on the success rate of clarithromycin-based eradication treatment.

BACKGROUND: Clarithromycin (CAM) resistance is a major contributor to the failure to eradicate Helicobacter pylori (H. pylori). The mixed-infection ratio of CAM-susceptible and CAM-resistant H. pylori strains differs among individuals. Pyrosequencing analysis can be used to quantify gene mutations at position each 2142 and 2143 of the H. pylori 23S rRNA gene in intragastric fluid samples. Herein, we aimed to clarify the impact of the rate of mixed infection with CAM-susceptible and CAM-resistant H. pylori strains on the success rate of CAM-containing eradication therapy. MATERIALS AND METHODS: Sixty-four H. pylori-positive participants who received CAM-based eradication therapy, also comprising vonoprazan and amoxicillin, were enrolled in this prospective cohort study. Biopsy and intragastric fluid samples were collected during esophagogastroduodenoscopy. H. pylori culture and CAM-susceptibility tests were performed on the biopsy samples, and real-time PCR and pyrosequencing analyses were performed on the intragastric fluid samples. The mutation rates and eradication success rates were compared. RESULTS: The overall CAM-based eradication success rate was 84% (54/64): 62% (13/21) for CAM-resistant strains, and 95% (39/41) for CAM-sensitive strains. When the mutation rate of the 23S rRNA gene was 20% or lower for both positions (2142 and 2143), the eradication success rate was 90% or more. However, when the mutation rate was 20% or higher, the eradication success rate was lower (60%). CONCLUSIONS: The mutation rate of the CAM-resistance gene was related to the success of eradication therapy, as determined via pyrosequencing analysis.

An Optical Fiber-Based Nanomotion Sensor for Rapid Antibiotic and Antifungal Susceptibility Tests.

The emergence of antibiotic and antifungal resistant microorganisms represents nowadays a major public health issue that might push humanity into a post-antibiotic/antifungal era. One of the approaches to avoid such a catastrophe is to advance rapid antibiotic and antifungal susceptibility tests. In this study, we present a compact, optical fiber-based nanomotion sensor to achieve this goal by monitoring the dynamic nanoscale oscillation of a cantilever related to microorganism viability. High detection sensitivity was achieved that was attributed to the flexible two-photon polymerized cantilever with a spring constant of 0.3 N/m. This nanomotion device showed an excellent performance in the susceptibility tests of Escherichia coli and Candida albicans with a fast response in a time frame of minutes. As a proof-of-concept, with the simplicity of use and the potential of parallelization, our innovative sensor is anticipated to be an interesting candidate for future rapid antibiotic and antifungal susceptibility tests and other biomedical applications.

Phenotypic and Genotypic Drug Resistance of Mycobacterium tuberculosis Strains Isolated from HIV-Infected Patients from a Third-Level Public Hospital in Mexico.

BACKGROUND: Drug-resistant tuberculosis (TB) is associated with higher mortality rates in patients with human immunodeficiency virus (HIV). In Mexico, the number of deaths due to TB among the HIV-positive population has tripled in recent years. METHODS: Ninety-three Mycobacterium tuberculosis strains isolated from the same number of HIV-infected patients treated in a public hospital in Mexico City were studied to determine the drug resistance to first- and second-line anti-TB drugs and to identify the mutations associated with the resistance. RESULTS: Of the 93 patients, 82.7% were new TB cases, 86% were male, and 73% had extrapulmonary TB. Most patients (94%) with a CD4 T-lymphocyte count <350 cells/mm3 were associated with extrapulmonary TB (p <0.0001), whilst most patients (78%) with a CD4 T-lymphocyte count >350 cells/mm3 were associated with pulmonary TB (p = 0.0011). Eighty-two strains were pan-susceptible, four mono-resistant, four poly-resistant, two multidrug-resistant, and one was extensively drug-resistant. In the rifampicin-resistant strains, rpoB S531L was the mutation most frequently identified, whereas the inhA C15T and katG S315T1 mutations were present in isoniazid-resistant strains. The extensively drug-resistant strain also contained the mutation gyrA D94A. CONCLUSIONS: These data highlight the need to promptly diagnose the drug resistance of M. tuberculosis among all HIV-infected patients by systematically offering access to first- and second-line drug susceptibility testing and to tailor the treatment regimen based on the resistance patterns to reduce the number of deaths in HIV-infected patients.

Analysis of Helicobacter pylori resistance in patients with different gastric diseases.

Helicobacter pylori (H. pylori) resistance is the most important risk factor for eradication failure. However, in most regions, antibiotic resistance rates of H. pylori in patients with different types of gastric mucosal lesions are still unclear. An 8-year clinical retrospective cohort study involving 2847 patients was performed. In this study, we first summarized and compared the resistance status of H. pylori in different years, ages, sexes, and gastric diseases. The resistance profiles of amoxicillin (AMX), clarithromycin (CLR), levofloxacin (LVX) and furazolidone (FR) and their changing trends in the clinic were described. Then, multiple antibiotic resistance in different gastric diseases and years were described and compared. The relationship between proton pump inhibitor (PPI) medication history and antibiotic resistance in H. pylori was also explored. Finally, an antibiotic resistance risk model was constructed for clinical resistance risk prediction. The overall resistance rates of AMX, CLR, LVX and FR in gastric diseases were 8.18%, 38.11%, 43.98%, and 13.73%, respectively. The mono resistance, double resistance, triple resistance, and quadruple resistance rates were 30.17%, 25.96%, 6.46%, and 0.63%, respectively. Compared with the period from 2014 to 2016, the rates of mono-resistance and multiple resistance all showed relatively downward trends in the past 5 years. Factors including age, sex, type of gastric lesions and recent PPI treatment history are associated with the antibiotic resistance rate of H. pylori. Atrophic gastritis is an important clinical feature of high-risk antibiotic resistance in H. pylori-infected patients. Patients with atrophic gastritis have higher risk of resistant strains infection. In this study, our data provide the association between antibiotic resistance of H. pylori and gastritis pattern, which indicate the higher risk of resistant strain infection if the patients with atrophic gastritis, PPI history and older age.

ß-Lactam Susceptibility of Streptococcus dysgalactiae subsp. equisimilis.

All clinical isolates of Streptococcus dysgalactiae subsp. equisimilis (SDSE) are considered susceptible to ß-lactams, the first-line drugs used for SDSE infections. However, penicillin-non-susceptible SDSE has been reported from Denmark. In this study, we attempted to detect ß-lactam-non-susceptible clinical isolates of SDSE in Japan. One hundred and fifty clinical isolates of S. dysgalactiae were collected in 2018, and species identification was performed using Rapid ID Strep API. The minimum inhibitory concentrations (MIC) of six ß-lactams (penicillin G, oxacillin, ceftizoxime, ceftibuten, cefoxitin, and cefaclor) were determined for 85 clinical isolates of SDSE using the agar dilution method standardized by the Clinical Laboratory Standards Institute. For the 85 isolates identified as SDSE, the MIC ranges of penicillin G, oxacillin, ceftizoxime, ceftibuten, cefoxitin, and cefaclor were 0.007-0.06, 0.03-0.12, 0.015-0.06, 0.25-2, 0.12-2, and 0.06-0.5 µg/mL, respectively. None of the clinical isolates were non-susceptible to penicillin G, indicating that all 85 clinical isolates of SDSE were susceptible to ß-lactams. Our findings indicate that almost all clinical isolates of SDSE in several prefectures of Japan remain susceptible to ß-lactams. Nevertheless, there remains a need for continuous and careful monitoring of drug susceptibility among clinical isolates of SDSE in Japan.

Pythium insidiosum: In vitro oomicidal evaluation of telithromycin and interactions with azithromycin and amorolfine hydrochloride.

This study evaluated the repositioning of the ketolide antibacterial telithromycin (TLT) against the oomycete Pythium insidiosum and verified the combination of TLT and the antimicrobials azithromycin (AZM) and amorolfine hydrochloride (AMR), which have known anti-P. insidiosum activity. Susceptibility tests of P. insidiosum isolates (n = 20) against the drugs were carried out according to CLSI protocol M38-A2, and their combinations were evaluated using the checkerboard microdilution method. The minimum inhibitory concentrations were 0.5-4 µg/mL for TLT, 2-32 µg/mL for AZM, and 16-64 µg/mL for AMR. For the TLT+AZM combination, 52.75 % of interactions were indifferent, 43.44 % were antagonistic, and 9.70 % were synergistic. As for interactions of the TLT+AMR combination, 60.43 % were indifferent, 39.12 % were antagonistic, and 10.44 % synergistic interactions. This study is the first to evaluate the repositioning of the antibacterial TLT against mammalian pathogenic oomycetes, and our results show that its isolated action is superior to its combinations with either AZM or AMR. Therefore, we recommend including TLT in future research to evaluate therapeutic approaches in different clinical forms of human and animal pythiosis.

Glucose-metabolism-triggered colorimetric sensor array for point-of-care differentiation and antibiotic susceptibility testing of bacteria.

Simple and sensitive discrimination of multiple bacteria and antimicrobial susceptibility test (AST) are significant for food safety, clinical diagnosis and treatment. Herein, based on different metabolic ability of bacteria on glucose, we presented a colorimetric sensor array for point-of-care testing (POCT) of multiple bacteria with methyl red (MER), bromothymol blue (BTB) and bromocresol green (BCG) as probes. Different bacteria resulted in different color changes of three probes, which was converted to RGB (Red (R)/Green (G)/Blue (B)) signals by the color recognizer APP loaded on smartphone. The sensor array performed differentiation of eleven species of bacteria, achieving the quantitative analysis of individual bacteria in tap water and differentiation of bacterial mixtures. Interestingly, the sensor array can be used for AST and evaluating minimal inhibitory concentration (MIC) of antibiotics to bacteria. The research provided meaningful guidance for distinguishing multiple bacteria and evaluating MIC, presenting great potential in practical application.

Clinical impact of antibiograms as an intervention to optimize antimicrobial prescribing and patient outcomes-A systematic review.

BACKGROUND: Antimicrobial stewardship (AMS) guidelines advocate for the use of antibiograms (cumulative antimicrobial susceptibility test data) as a tool to guide empirical antibiotic prescribing and inform local treatment guidelines. The objective of this review is to evaluate the effectiveness of antibiograms as an intervention to optimize antimicrobial prescribing and patient outcomes. METHODS: Embase, PubMed, CINAHL, and International Pharmacy Abstracts (IPA) databases were searched from inception until September 2022, to identify studies of antibiogram-related interventions in all health care settings. The National Institutes of Health Quality Assessment Tools were used to assess the methodological quality of the included studies. RESULTS: Of the 37 included studies, the majority of studies were conducted in the United States (n = 25) and in hospital settings (n = 27). All interventions were multifaceted and in 26 (70%) studies, facility-specific antibiograms could be considered as an integral component of the interventions. A positive impact on antibiotic consumption trends (17 studies), appropriateness of prescribing (16 studies), and cost of treatment (6 studies) was found, with minimal evidence for improvement in mortality, hospitalization, and resistance profiles. Due to the heterogeneity in study designs and outcomes, a meta-analysis was not performed. CONCLUSIONS: AMS interventions including antibiograms may improve antibiotic use, appropriateness, and costs. Multifaceted interventions were often used, which precludes drawing conclusions about the effectiveness of antibiograms alone as an AMS tool.

Cost-Efficient Micro-Well Array-Based Colorimetric Antibiotic Susceptibility Testing (MacAST) for Bacteria from Culture or Community.

Rapid and cost-efficient antibiotic susceptibility testing (AST) is key to timely prescription-oriented diagnosis and precision treatment. However, current AST methods have limitations in throughput or cost effectiveness, and are impractical for microbial communities. Here, we developed a high-throughput micro-well array-based colorimetric AST (macAST) system equipped with a self-developed smartphone application that could efficiently test sixteen combinations of bacteria strains and antibiotics, achieving comparable AST results based on resazurin metabolism assay. For community samples, we integrated immunomagnetic separation into the macAST (imacAST) system to specifically enrich the target cells before testing, which shortened bacterial isolation time from days to only 45 min and achieved AST of the target bacteria with a low concentration (~103 CFU/mL). This proof-of-concept study developed a high-throughput AST system with an at least ten-fold reduction in cost compared with a system equipped with a microscope or Raman spectrum. Based on colorimetric readout, the antimicrobial susceptibility of the bacteria from microbial communities can be delivered within 6 h, compared to days being required based on standard procedures, bypassing the need for precise instrumentation in therapy to combat bacterial antibiotic resistance in resource-limited settings.

Uropathogens and their antimicrobial-resistant pattern among suspected urinary tract infections patients in eastern Nepal: A hospital inpatients-based study.

Background: Urinary tract infections are the primary factors that cause mortality and morbidity in patients with underlying comorbid conditions and are responsible for most hospital admissions worldwide. Objectives: The study aims to identify the common bacterial uropathogens and determine their antimicrobial susceptibility pattern, including multidrug-resistant/extensively drug-resistant bacteria. Methods: The descriptive cross-sectional study was conducted among inpatients provisionally suspected of urinary tract infections in the medical ward of Koshi Hospital, Biratnagar, Nepal. Samples were inoculated in a cystine lysine electrolyte-deficient medium, and pure growth of significant bacteria was further subjected Gram staining, biochemical identification, and antimicrobial susceptibility testing as per laboratory standard procedure and Clinical Laboratory Standards Institute guidelines, respectively. Descriptive and inferential statistical analysis was performed to analyze the outcomes and a p-value < 0.05 was considered statistically significant. Results: A total of 305 patients urine specimens were examined, of which 251 (82.29%) samples resulted in significant bacterial growth in the culture. Escherichia coli (62.94%) was the most predominantly isolated organism, followed by Klebsiella pneumoniae (12.35%), Staphylococcus aureus (9.16%), and Pseudomonas aeruginosa (8.76%). Among antimicrobials, colistin had shown absolute susceptibility (100%) toward gram-negative uropathogens followed by carbapenem and aminoglycosides in a majority of uropathogens. Escherichia coli was found to be the leading drug-resistant bacteria (70%) among uropathogens. The presence of multidrug-resistant/extensively drug-resistant bacteria uropathogens was found to be significantly associated with diabetes mellitus and those with combined antimicrobial therapies. Diabetic patients were twice (OR~2) more likely to colonize and develop uropathogens as compared to non-diabetics. Conclusion: Escherichia coli was the most common uropathogens followed by Klebsiella pneumoniae in urinary tract infection patients. The polymyxin group (colistin) of antimicrobials was found to be effective in all multidrug-resistant and extensively drug-resistant uropathogens. The study recommends the need of optimized antimicrobial stewardship program to develop effective strategies in the management of urinary tract infections in diverse healthcare settings.

In vitro Azole Susceptibility Testing of Japanese Isolates of Itraconazole-Resistant Dermatophytes.

We conducted antifungal susceptibility testing on itraconazole (ITCZ)-resistant isolates of Trichophyton interdigitale and Trichophyton rubrum collected from Japanese patients in 2021 and 2022. The aim of the present study was to determine the most effective drug against ITCZ-resistant strains of dermatophytes. In all isolates, the minimum inhibitory concentrations (MICs) were > 32 mg/l for ITCZ, < 0.03 to 0.5 mg/l for ravuconazole (RVCZ), and < 0.03 mg/l for efinaconazole (EFCZ), luliconazole (LUCZ), and terbinafine (TRBF). Thus, in tinea unguium cases with ITCZ-resistant strains, treatment should be switched to TRBF or other azoles with a stronger antifungal efficacy, such as EFCZ, LUCZ, or RVCZ, and treatment must continue until the infectious organisms are completely eliminated.

Resazurin microplate test method for rapid determination of colistin resistance in carbapenem-resistant Acinetobacter baumanii isolates.

BACKGROUND: Colistin-resistant Acinetobacter baumannii isolates are extremely important pathogens for hospital-acquired infections. OBJECTIVE: To investigate the effectiveness of the resazurin microplate assay (REMA) for the rapid determination of colistin resistance. METHODS: Susceptibility for colistin was investigated in vitro by the broth microdilution method (BMD) and the resazurin microplate assay (REMA) on 106 carbapenem-resistant Acinetobacter baumannii isolates. RESULTS: The results of both test methods were compared, and the categorical agreement between them was found to be 100%. No minor, major, or very major discrepancy was observed between the 2 methods. CONCLUSIONS: The most important advantages of REMA are that the results are obtained within 6 hours compared to the reference method, that it is easy to evaluate because it is colorimetric, and that the susceptibility result can be reported to the clinician on the same day as bacterial identification.

The Impact of Information Quality of Antimicrobial Susceptibility Test Report on the Rational Antimicrobial Use: A Retrospective Study.

Background: Antimicrobial susceptibility test (AST) report was important for rational antimicrobial use. However, the reference value of AST report was sometimes limited due to poor information quality (IQ). This study aimed to measure the IQ of AST and evaluate the impact of IQ of AST report on rational antimicrobial use as a reference for antimicrobial therapy. Methods: The retrospective study included data of AST report, antimicrobials prescribed after reporting AST results and related inpatient information. The inclusion criteria of the AST report included three conditions: 1. The AST reports were from inpatients with diagnosis of infection. 2. The bacteria were extracted from a sterile-site specimen. 3. The interpretive categories (ie sensitive, intermediary or resistance) were firstly reported during one hospitalization. The IQ of AST report was measured by the total IQ and IQ of completeness, usefulness, accuracy and consistency. The rational antimicrobial use was measured by the antimicrobial adherence to the interpretive categories of AST report. Fractional logit regression model (FLRM) was chosen to evaluate the impact of IQ on the rational antimicrobial use. Results: The median of the total IQ, completeness, usefulness, accuracy and consistency were 0.7345, 0.6082, 0.9167, 0.8966 and 1.0000, respectively. The results of FLRM showed that usefulness, accuracy and consistency had significant positive impacts on the rational antimicrobial use (ß = 4.220, P < 0.001; ß = 3.987, P < 0.001; ß = 0.511, P = 0.001, respectively), while the total IQ and completeness had no statistically significant impacts on the rational antimicrobial use (ß = -0.820, P = 0.35; ß = -0.793, P = 0.20, respectively). Conclusion: This study confirmed that usefulness, accuracy and consistency performed well and had positive impacts on the rational antimicrobial use, which indicated that improving IQ especially usefulness, accuracy and consistency would make AST report play a greater role in promoting the rational antimicrobial use.

In vitro combination with doxycycline plus antifungals against clinical Mucorales pathogens.

PURPOSE: Since systematic antifungals for mucormycosis showed variable MICs depending on strains, effective and safe antifungal therapy was still needed. This study is aimed to evaluate the in vitro activity of doxycycline combined with antifungal therapy against dominant Mucorales pathogens. METHODS: Multidrug susceptibility testing was performed with doxycycline and antifungals, including itraconazole, posaconazole, and amphotericin, in 21 isolates of 8 dominant Mucorales pathogens. RESULTS: The fractional inhibitory concentration index according to M38 showed one Rhizopus arrhizus isolate synergic (∑FICI = 0.375) and other isolates in addition (0.5 < ∑FICI < 4). CONCLUSIONS: Doxycycline was found to have in vitro advantages in combined antifungal treatment over antifungals alone.

Rapid Mycobacterium abscessus antimicrobial susceptibility testing based on antibiotic treatment response mapping via Raman Microspectroscopy.

OBJECTIVES: Antimicrobial susceptibility tests (ASTs) are pivotal tools for detecting and combating infections caused by multidrug-resistant rapidly growing mycobacteria (RGM) but are time-consuming and labor-intensive. DESIGN: We used a Mycobacterium abscessus-based RGM model to develop a rapid (24-h) AST from the beginning of the strain culture, the Clinical Antimicrobials Susceptibility Test Ramanometry for RGM (CAST-R-RGM). The ASTs obtained for 21 clarithromycin (CLA)-treated and 18 linezolid (LZD)-treated RGM isolates. RESULTS: CAST-R-RGM employs D2O-probed Raman microspectroscopy to monitor RGM metabolic activity, while also revealing bacterial antimicrobial drug resistance mechanisms. The results of clarithromycin (CLA)-treated and linezolid (LZD)-treated RGM isolates exhibited 90% and 83% categorical agreement, respectively, with conventional AST results of the same isolates. Furthermore, comparisons of time- and concentration-dependent Raman results between CLA- and LZD-treated RGM strains revealed distinct metabolic profiles after 48-h and 72-h drug treatments, despite similar profiles obtained for both drugs after 24-h treatments. CONCLUSIONS: Ultimately, the rapid, accurate, and low-cost CAST-R-RGM assay offers advantages over conventional culture-based ASTs that warrant its use as a tool for improving patient treatment outcomes and revealing bacterial drug resistance mechanisms.

Case report: First isolation of Exophiala dermatitidis from subcutaneous phaeohyphomycosis in a cat.

Phaeohyphomycosis, which is caused by the opportunistic black yeast-like fungus Exophiala dermatitidis, has been reported in humans and dogs. However, no previous studies describing E. dermatitidis infections in cats have been published. Herein, we report a case of subcutaneous phaeohyphomycosis caused by E. dermatitidis. A 12-year-old, castrated male Japanese domestic short-haired cat presented with a solitary subcutaneous abscess on the left side of the neck, where an esophageal tube for force-feeding had been placed previously. The cat was diagnosed with hepatitis and was treated with prednisolone. The subcutaneous abscess was incised using a scalpel blade and the pus was excreted. The cytology of the pus revealed hyphae with neutrophil and macrophage infiltration. Although the cat was treated with oral itraconazole or an infusion of topical ketoconazole cream applied to the lesion, it died. The fungal culture of the pus specimen developed dark-green, waxy, smooth, yeast-like colonies. Sequencing of the internal transcribed spacer 1-4 regions of the ribosomal DNA of the pus specimen showed 100% identity with that of the standard strains of E. dermatitidis. Based on these results, the cat was diagnosed with subcutaneous phaeohyphomycosis caused by E. dermatitidis. The antifungal susceptibility test revealed that the fungus showed low or moderate susceptibility to the antifungal drugs examined, except for amphotericin B, which exhibited high in vitro antifungal activity. This is the first case report to provide definitive evidence of E. dermatitidis infection in cats and antifungal susceptibility test results against clinically isolated E. dermatitidis.

Updating breakpoints in the United States: a summary from the ASM Clinical Microbiology Open 2022.

Accurate antimicrobial susceptibility testing (AST) and reporting are essential for guiding appropriate therapy for patients and direction for public health prevention and control actions. A critical feature of AST reporting is the interpretation of AST results using clinical breakpoints for reporting as susceptible, susceptible-dose dependent, intermediate, or resistant. Breakpoints are subject to continuous adjustment and updating to best reflect current clinical data. These breakpoint changes can benefit patients and public health only if adopted in a timely manner. A recent survey identified that up to 70% of College of American Pathologists (CAP)-accredited U.S. laboratories and 45% of CAP-accredited laboratories outside the U.S. use various obsolete clinical breakpoints to interpret AST results to guide patient care. The reason for the ongoing use of obsolete breakpoints is multifactorial, including barriers encountered by laboratories, commercial AST device manufacturers, standards development organizations, and regulatory bodies alike. To begin to address this important patient safety issue, CAP implemented checklist requirements for CAP-accredited laboratories to ensure up-to-date clinical breakpoint use. Furthermore, the topic was discussed at the June 2022 American Society for Microbiology Clinical Microbiology Open (CMO) with various stakeholders to identify potential solutions. This minireview summarizes the breakpoint setting process in the U.S. and highlights solutions to close the gap between breakpoint revisions and implementation in clinical and public health laboratories. Solutions discussed include clarification of data requirements and minimum inhibitory concentration only reporting for regulatory clearance of AST devices, clinical data generation to close breakpoints gaps, advocacy, education, and greater dialogue between stakeholders.

Cumulative antimicrobial susceptibilities for respiratory clinical isolates of Mycobacterium avium Complex, Mycobacterium kansasii, and Mycobacterium abscessus from Pakistan 2018 to 2022.

Background: Nontuberculous mycobacteria (NTM) are increasingly identified as causes of protracted pulmonary infections. Antibiotic susceptibility testing requires microdilution methods, which are often unavailable in laboratories in resource-poor settings. We report cumulative antibiograms for the most frequently isolated clinical pulmonary NTM from Pakistan to inform empiric antibiotic management of initial NTM infections. Methods: We analyzed data from 2018 to 2022 for the most frequently isolated and clinically relevant NTM isolated from respiratory specimens, i.e., Mycobacterium avium complex (MAC), Mycobacterium abscessus group (MAG), and Mycobacterium kansasii (MK). Antibiograms were developed using the Clinical Laboratory Standards Institute's M39ED5 standard. Percentage susceptibilities and 95% confidence intervals (CI) were calculated. Results: Over 4 years, 529 NTM, comprising 209 MAC, 249 MAG, and 71 MK were analyzed. For MAC and MAG, where clarithromycin (CLR)-based regimens are recommended, CLR was active for 94.8% (95% CI 91.3-96.9), and 77.5% (95% CI 71.4-82.7) isolates, respectively. Combination regimens comprising 3 active drugs CLR + linezolid (LZD) + moxifloxacin for MAC and CLR + LZD + Amikacin for MAG had 98.4% (95% CI 95.9-99.4) and 68.9% (95% CI 62.3-74.8) coverage for pulmonary disease, respectively. For MK, 91.5% (95% CI 82.8-96.1) isolates were susceptible to rifampin (RIF), with a combination of RIF + CLR covering 88.7% (95% CI 79.3-94.2) of MK pulmonary infections, respectively. Conclusions: These data can inform empiric treatment guidance for the most common NTM pulmonary infections, i.e., for MAC, MAG, and MK disease in Pakistan.