Resistance Rates Research Articles

Impact of discontinuing routine fluoroquinolone prophylaxis in neutropenic allogeneic haematopoietic stem cell transplant recipients: an observational study.

Uncertainty exists as to the role of fluoroquinolone (FQ) prophylaxis for patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT) in the era of rising antibiotic resistance. We aimed to evaluate rates of bloodstream infections (BSI), resistance patterns and outcomes of patients after discontinuing routine FQ prophylaxis administration. All adult recipients of first HSCT from 2017 to 2020 were retrospectively included and classified according to time of HSCT as FQ group (HSCT January 2017-December 2018) or no FQ group (January 2019-December 2020). The primary outcome was Gram-negative (GN) BSI from day -7 to 30 days post-HSCT. The independent association between the study period and BSI was assessed using survival analysis, and adjusting for confounders. We included 254 patients, 130 (51%) and 124 (49%) in the FQ and no FQ groups, respectively. Compared to the FQ group, no FQ had significantly more GN BSI (21% versus 33%, P = 0.027) and the median time to first GN BSI was significantly shorter [4 (IQR 1-8) days versus 6 (1-10) days, P = 0.009]. Following adjustment, FQ prophylaxis remained associated with lower hazard for GN BSI (hazard ratio 0.57, 95% CI 0.34-0.93). Eighty-two GN BSI episodes had FQ susceptibility testing. More GN BSI episodes were FQ resistant in the FQ group (68.9% versus 41.6%, P = 0.021). No significant difference was found for 30-day mortality, time to first febrile neutropenia and time to first broad-spectrum antibiotics between the groups (P was not significant). FQ prophylaxis is associated with fewer GN BSI in the early post-HSCT period even in high FQ resistance settings, with FQ resistance rates reaching >60% following prophylaxis.

Prevalence of pathogens and antimicrobial resistance of isolated Staphylococcus spp. in bovine mastitis milk in South Korea, 2018-2022.

Staphylococcus spp. are one of the most predominant isolates in milk samples of dairy cows with mastitis worldwide. The aims of this study were to investigate the prevalence of bacterial pathogens in bovine mastitis milk samples in South Korea and the antimicrobial resistance profiles of staphylococcal isolates. In total, 1,245 strains were isolated from 1,260 mastitis quarter milk samples (with somatic cell counts ≥200,000 cells/mL) from 66 dairy farms between 2018 and 2022. The bacterial genus with the highest prevalence in bovine mastitis milk samples was Staphylococcus spp. (33.9%), followed by Streptococcus spp. (11.5%). S. aureus and non-aureus staphylococci (NAS) accounted for 11.0% and 89.0% of staphylococcal isolates, respectively. S. chromogenes was the most prevalent species among the 22 NAS species detected. S. aureus showed the highest resistance rates to penicillin (25.0%) and ampicillin (20.8%), whereas NAS showed the highest resistance rates to penicillin (18.3%), tetracycline (11.4%) and erythromycin (10.1%). Sixteen multidrug-resistant (MDR) isolates were only isolated from NAS, and the most commonly detected antimicrobial resistance gene in the 16 MDR isolates was mecA (75.0%), followed by tetK (62.5%), blaZ (50.0%), ermC (50.0%), and lnuA (43.8%). In conclusion, NAS were the most common isolates from mastitis milk in South Korea and MDR isolates carried a variety of antibiotic resistance genes. Our study suggests that continuous monitoring of the distribution and antimicrobial resistance in Staphylococcus spp., particularly NAS, is needed to improve the effectiveness of management and treatment strategies in dairy farms.

Overall status of carbapenem resistance among clinical isolates of Acinetobacter baumannii: a systematic review and meta-analysis.

Resistance to carbapenems, the first-line treatment for infections caused by Acinetobacter baumannii, is increasing throughout the world. The aim of the present study was to determine the global status of resistance to carbapenems in clinical isolates of this pathogen, worldwide. Electronic databases were searched using the appropriate keywords, including: 'Acinetobacter' 'baumannii', 'Acinetobacter baumannii' and 'A. baumannii', 'resistance', 'antibiotic resistance', 'antibiotic susceptibility', 'antimicrobial resistance', 'antimicrobial susceptibility', 'carbapenem', 'carbapenems', 'imipenem', 'meropenem' and 'doripenem'. Finally, following some exclusions, 177 studies from various countries were included in this study. The data were then subjected to a meta-analysis. The average resistance rate of A. baumannii to imipenem, meropenem and doripenem was 44.7%, 59.4% and 72.7%, respectively. A high level of heterogeneity (I2 > 50%, P value < 0.05) was detected in the studies representing resistance to imipenem, meropenem and doripenem in A. baumannii isolates. Begg's and Egger's tests did not indicate publication bias (P value > 0.05). The findings of the current study indicate that the overall resistance to carbapenems in clinical isolates of A. baumannii is relatively high and prevalent throughout the world. Moreover, time trend analysis showed that the resistance has increased from the year 2000 to 2023. This emphasizes the importance of conducting routine antimicrobial susceptibility testing before selecting a course of treatment, as well as monitoring and controlling antibiotic resistance patterns in A. baumannii strains, and seeking novel treatment options to lessen the emergence and spread of resistant strains and to reduce the treatment failure.

Dose-escalation of second-line and first-line asciminib in chronic myeloid leukemia in chronic phase: the ASC2ESCALATE Phase IItrial.

Up to 40% of newly diagnosed patients with chronic myeloid leukemia in chronic phase (CML-CP) discontinue treatment by 5 years, primarily due to resistance or intolerance. Rates of resistance to second-line (2L) treatment are also high. Some patients with resistance respond with dose escalation of tyrosine kinase inhibitors (TKIs). Asciminib demonstrated safety and efficacy across a broad dosage range. ASC2ESCALATE is an ongoing, Phase II, multicenter, single-arm, dose-escalation study of asciminib in 2L and first-line treatment of CML-CP. The primary end point is major molecular response at 12months in 2L. Secondary end points include molecular responses at and by scheduled time points, survival, and safety. ASC2ESCALATE is the first study investigating asciminib in CML-CP following failure of one prior TKI.Clinical Trial Registration: NCT05384587 (ClinicalTrials.gov).

Comparative Efficacy of Current and Emerging Therapies for Cutaneous and Visceral Leishmaniasis: A Global Perspective

Leishmaniasis treatment has faced challenges with pentavalent antimonials, historically used but now showing resistance and high failure rates. The World Health Organization (WHO) recommended higher doses, but resistance in Nepal and misuse persist. Antimonials are no longer the preferred treatment for visceral leishmaniasis (VL) in the Indian subcontinent but are still used for cutaneous leishmaniasis (CL). Amphotericin B, especially liposomal amphotericin B (L-AmB), has become the preferred treatment for VL in the Indian subcontinent, with high efficacy and shorter treatment courses. Genetic insights into leishmaniasis reveal that parasite species and host immune responses are key factors in disease variation. Genetic analysis of atypical parasite isolates shows that genetic variations can lead to different disease patterns. Whole genome sequencing and proteomic analyses offer fresh insights into how parasite genes and proteins impact drug resistance, post-kala-azar dermal leishmaniasis (PKDL), and unusual disease presentations. Variations in hereditary unit copy numbers and single nucleotide polymorphisms contribute to genetic diversity and distinct tissue distribution, leading to distinct disease patterns. Genomic markers for drug resistance in Leishmania parasites include ATP-binding cassette (ABC) transporters, amino acid permease 3 (AAP3), and proteins like phosphoglycerate kinase (PGK) and mitogen-activated protein kinase (MAPK). These markers are associated with efflux of thiols and metals, antimony resistance, and protection against oxidative stress. Additionally, key proteins and enzymes in antioxidant defense mechanisms, such as iron superoxide dismutase-A (FeSOD-A), folate transporter 1 (FT1), and heat shock protein 83 (HSP83), play roles in drug resistance and parasite survival.

Characterization of clinical infection and drug resistance of group B streptococcus in Chengdu, China

ObjectiveTo investigate the clinical infection characteristics and antibiotic resistance of Group B Streptococcus (Streptococcus agalactiae, GBS) in Chengdu, China, from 2019 to 2021, as well as to provide data to support rational clinical drug use. MethodsThis was a retrospective study to collect 203 culture-positive GBS strains isolated from January 2019 to December 2021 in Chengdu, China, all of which were identified by the VITEK 2 Compact automated microbial Bacterial identification instrument. Data were derived using WHONET 5.6 software. The sample type and ward distribution were counted. Pregnant women and newborns were screened from the original data and their pregnancy outcomes were calculated respectively. ResultsGBS strains were mainly concentrated in obstetrics and neonatology departments, accounting for 40.9 % and 33.5 %. The types of specimens were mainly vaginal secretions, amniotic fluid and sputum, accounting for 25.6 %, 26.1 % and 18.7 %, respectively. Chorioamnionitis, premature rupture of membranes and preterm delivery occurred mainly in pregnant women after infection, accounting for 44.4 %, 31.5 % and 24.1 %. Neonates, on the other hand, were mainly diagnosed with neonatal pneumonia, neonatal sepsis, respiratory failure and septic meningitis, accounting for 91.8 %, 61.2 %, 44.9 % and 16.3 % of all positive neonates. 840 pregnant women were screened for GBS colonization from 2019 to 2021, and a total of 108 GBS positive pregnant women were identified, with a GBS colonization rate of 12.9 %. A total of 9 neonates from 108 GBS positive pregnant women developed early-onset disease. The morbidity in neonates was 8.3 %. No strains resistant to penicillin and ampicillin were found, while the resistance rates of tetracycline and clindamycin were higher than 50 %, respectively 60.1 % and 53.2 %. ConclusionGBS infection mainly affected pregnant women and newborns in Chengdu, China, which can lead to adverse maternal and infant outcomes. Attention should be paid to strengthening general screening of GBS in perinatal urogenital secretions and the prevention strategy of IAP (intrapartum antibiotic prophylaxis). Antimicrobial therapy should be administered with appropriate antibiotics. Penicillin was still the first line drug for the treatment of GBS. These initiatives were important to reduce mother-to-child transmission and neonatal infections.

Multi-Locus Sequence Typing-Based Genetic Analysis, Antifungal Resistance, and Clinical Prognosis of Cryptococcus neoformans Infections in HIV-Infected Patients in Northern China.

This study aimed to investigate the molecular epidemiological characteristics and drug sensitivity of Cryptococcus from HIV-infected patients and their relationship with patients' prognosis. Seventy-six strains were collected and identified to the species level by matrix-assisted laser desorption ionization-time of flight mass spectrometry, confirmed by internal transcribed spacer sequencing. Multi-locus sequence typing was used for the typing of Cryptococcus, and its antifungal susceptibility was tested using FUNGUS 3. The clinical outcomes of the patients were reviewed at 3-, 6-, 9-, and 12-month follow-ups. All strains were Cryptococcus neoformans var. grubii classified into seven sequence types (STs) dominated by ST5, ST31, and a new ST702 strain. The 6- and 9-month survival rates were highest for patients infected with ST31, ST32, and ST174. The antifungal resistant rates were 13.2%, 2.6%, and 1.4% for fluconazole, amphotericin B, and 5-fluorocytosine. Except itraconazole, the minimum inhibitory concentration (MIC) values and wild type (WT)/non-wild type (NWT) of Cryptococcus for antifungal drugs were not related to the clinical prognosis of HIV-infected patients with cryptococcal infection. ST5 was the main ST type, and the new ST702 type was found in a patient who died in a short period of time. Cryptococcus neoformans var. grubii had a relatively high antifungal drug resistance rate to fluconazole. The WT strain accounted for the highest proportions for 5-fluorocytosine, amphotericin B, fluconazole, voriconazole, and itraconazole. The MIC values of Cryptococcus for first-line antifungal drugs showed no relationship with clinical prognosis, implying that MIC values cannot be used to predict the clinical outcome of these patients.

Analysis of the changes of bacterial spectrum and drug resistance in sputum culture of ICU children in a hospital of pediatric in Jiangsu Province from 2017 to 2022

Objective: To investigate the changes of the distribution and drug resistance profile of bacteria from ICU children with lower respiratory tract infection (LRTI) in Suzhou City, Jiangsu Province from 2017 to 2022. Methods: From January 2017 to December 2022, a cross-sectional observational study on the bacterial spectrum analysis among intensive care unit (ICU) children with LRTI was conducted in Children's Hospital of Soochow University. The bacteria was cultivated by culture methods from sputum samples, and identified by MALDI-TOF mass spectrometry. Drug sensitivity tests were performed by the VITEK2 Compact fully automated analysis system and the paper slide method. The χ2 test or Fisher's exact probability was used to analyze the changes of the distribution of sputum culture-positive bacteria and drug resistance in ICU children. Results: The overall detection rate of sputum culture was 42.06% (1 182/2 810). Staphylococcus aureus (25.63%,303/1 182), Acinetobacter baumannii (13.62%,161/1 182) and Haemaphilus influenzae (13.28%,157/1 182) were the top three. Proportions of Acinetobacter baumannii (17.90% vs. 11.02%,χ²=11.17, P=0.001), especially carbapenem-resistant Acinetobacter baumannii (43.70% vs. 23.50%, χ²=15.21, P<0.001) increased significantly from 2020 to 2022. However, the proportions of Haemophilus influenzae (8.50% vs. 16.19%, χ²=14.27, P<0.001), Streptococcus pneumoniae (8.50% vs. 15.92%, χ²=13.42, P<0.001) and extended-spectrum-lactamase producing Escherichia coli (8.89% vs. 18.00%, χ²=5.45, P=0.025) decreased. Drug resistant results showed that Acinetobacter baumannii was obviously more resistant to imipenem (χ²=4.43, P=0.035) and levofloxacin (χ²=12.53, P<0.001), while more sensitive to minocycline (χ²=8.34, P=0.004). Escherichia coli showed a significant increase in resistance to piperacillin tazobactam (χ²=8.29, P=0.008) and cefoperazone sulbactam (χ²=5.07, P=0.024) from 2020 to 2022; Klebsiella pneumoniae consistently maintained a resistance rate of more than 60% to first and second-generation cephalosporins, and remain susceptible to quinolones and carbapenems. Staphylococcus aureus remained highly susceptible to levofloxacin (drug resistance rate: 2.31%,7/303) and sulfamethoxazole/trimethoprim (drug resistance rate: 4.95%,15/303) from 2020 to 2022. Conclusion: Higher detection and resistance rates of Acinetobacter baumannii from sputum culture in ICU children from 2020 to 2022 were explored. Resistance of Escherichia coli to β-lactamase inhibitor combinations was more serious. Regular monitoring the changes of the etiology of respiratory tract infections in ICU Children is particularly important for the prevention and treatment of multidrug-resistant bacterial infections.

Parasitological prevalence of scabies and secondary bacterial infections among scabies suspected patients at Borumeda General Hospital, Northeast Ethiopia

BackgroundScabies disproportionately affects people in resource-poor areas. Clinical diagnosis risks misdiagnosis due to resemblance to other skin diseases, but laboratory confirmation improves accuracy. Scabies allow for secondary bacterial infections. Associated bacteria exacerbate scabies and antibiotic resistance. Ethiopian scabies diagnosis relies solely on clinical exams without confirming parasites or investigating secondary bacterial infections. This study aims to identify parasites via scraping, isolate secondary bacteria, and evaluate their antibiotic susceptibility profiles.MethodsA hospital based cross-sectional study was conducted from September 2022 to July 2023 among scabies suspected patients who visited the dermatology clinic at Borumeda General Hospital in Northeast Ethiopia. A systematic random sampling technique was used to select 422 study participants. Socio-demographic, hygiene, and clinical characteristics data were collected via face-to-face interviews and observation. Skin scrapings for parasitological investigations and swab samples for microbiological investigations were collected and transported for analysis and drug susceptibility testing. Descriptive statistics and logistic regression analysis were employed to assess risk factors.ResultAmong 422 skin scraping samples, 156 (37.0%) cases of scabies were microscopically confirmed. Bed-sharing and having contact history were independent predictors of microscopically confirmed scabies. The prevalence of secondary bacterial infections among scabies-confirmed patients was 35.9% (56/156). The most prevalent bacterial species were Staphylococcus aureus, coagulase-negative staphylococci, and Streptococcus pyogenes. Tetracycline for Gram-positive bacteria and ampicillin for Gram-negative bacteria showed the highest rate of resistance. In both Gram-positive and Gram-negative strains, multidrug resistance was also observed.ConclusionThis study found that over one-third of skin scrapings tested positive for scabies. Additionally, more than one-third of scabies cases were complicated by secondary bacterial infections. Improved scabies diagnosis and consideration of secondary bacterial infections are important for better controlling this neglected tropical disease.

Efficacy and safety of intra-articular-only meropenem after one-stage revision for treating Escherichia coli-induced periprosthetic joint infection in a rat model.

The optimum type of antibiotics and their administration route for treating Gram-negative (GN) periprosthetic joint infection (PJI) remain controversial. This study aimed to determine the GN bacterial species and antibacterial resistance rates related to clinical GN-PJI, and to determine the efficacy and safety of intra-articular (IA) antibiotic injection after one-stage revision in a GN pathogen-induced PJI rat model of total knee arthroplasty. A total of 36 consecutive PJI patients who had been infected with GN bacteria between February 2015 and December 2021 were retrospectively recruited in order to analyze the GN bacterial species involvement and antibacterial resistance rates. Antibiotic susceptibility assays of the GN bacterial species were performed to screen for the most sensitive antibiotic, which was then used to treat the most common GN pathogen-induced PJI rat model. The rats were randomized either to a PJI control group or to three meropenem groups (intraperitoneal (IP), IA, and IP + IA groups). After two weeks of treatment, infection control level, the side effects, and the volume of antibiotic use were evaluated. Escherichia coli was the most common pathogen in GN-PJI, and meropenem was the most sensitive antibiotic. Serum inflammatory markers, weightbearing activity, and Rissing score were significantly improved by meropenem, especially in the IA and IP + IA groups ( p < 0.05). Meropenem in the IA group eradicated E. coli from soft-tissue, bone, and prosthetic surfaces, with the same effect as in the IP + IA group. Radiological results revealed that IA and IP + IA meropenem were effective at relieving bone damage. Haematoxylin and eosin staining also showed that IA and IP + IA meropenem improved synovial inflammation and bone destruction. No pathological changes in the main organs or abnormal serum markers were observed in any of the meropenem-treated rats. The IA group required the lowest amount of meropenem, followed by the IP and IP + IA groups. IA-only meropenem with a two-week treatment course was effective and safe for PJI control following one-stage revision in a rat model, with less meropenem use.

Antibiotic susceptibility of uropathogens: a 3-year retrospective study at Ho Teaching Hospital of Ghana

BackgroundUrinary tract infection (UTI) remains one of the most treated infections in primary healthcare over the last two decades. The infection is treated with antibiotics. However, there have been reported cases of increasing antibiotic resistance globally, limiting the available antibiotics for the treatment of the infection. The study aimed to determine the frequency of bacterial urinary tract infections and their antibiotic resistance pattern in Ho Teaching Hospital of Ghana from 2019–2021.MethodologyData on urine culture and susceptibility testing and patient demographics from 2019–2021 were collected from the microbiology unit archives with a designed Microsoft Excel 2019 form and later exported to IBM SPSS (v26) for statistical analysis on the uropathogens and their antibiotic resistance pattern. P-value < 0.05 was considered statistically significant.ResultsOut of 4806 records, 1005 bacterial isolates were found, with a total prevalence of 20.91%. The most prevalent group of organisms was the Enterobacteriaceae, with E. coli 409 (40.70%) being the most frequent isolate. Of the 772 isolates subjected to amikacin, 48(6.22%) and 6(0.78%) of the Gram-negative and Gram-positive bacterial organisms showed resistance to the antibiotic respectively. 58.96% (148/251) and 3.59% (9/251) of Gram-negatives and Gram-positives were resistant to cotrimoxazole. Out of the 1005 bacterial isolates, 165(16.42%), 161(16.02%) and 2(0.20%) showed multidrug resistance (MDR), extensively-drug resistance (XDR), and pandrug resistance (PDR) respectively.ConclusionThere was a high antibiotic-resistant pattern among the uropathogens reported in this current study, hence, the Standard Treatment Guidelines may need to be updated to reflect the high rates of antibiotic resistance exhibited by most prevalent isolates.

Maternal vascular indices and hemodynamic parameters at 36 weeks' gestation in gestational and pre-existing diabetes mellitus.

To compare maternal vascular indices and hemodynamic parameters at 35-37 weeks' gestation in pregnancies complicated by gestational diabetes mellitus (GDM), those with pre-existing diabetes mellitus (DM) and those without GDM or pre-existing DM. This was a prospective observational study in women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The visit included recording of maternal demographic characteristics and medical history, and measurement of vascular indices and hemodynamic parameters using a non-invasive operator-independent device. These included carotid-to-femoral pulse-wave velocity, augmentation index, cardiac output, stroke volume, central systolic and diastolic blood pressure, total peripheral resistance and heart rate. The values in the GDM and pre-existing DM groups were compared to those in the unaffected group. We examined 6746 women, of whom 396 were excluded because they had chronic hypertension or developed pre-eclampsia or gestational hypertension. The study population of 6350 pregnancies contained 99 (1.6%) with pre-existing Type-I or Type-II DM and 617 (9.7%) that developed GDM, including 261 (42.3%) that were treated with diet alone, 239 (38.7%) treated with metformin alone and 117 (19.0%) treated with insulin with or without metformin. Among women with GDM and those with pre-existing DM, compared to those without GDM or pre-existing DM, there was a higher median cardiac output and heart rate, central systolic and diastolic blood pressure and pulse-wave velocity, but there was no significant difference in stroke volume and total peripheral resistance. There were no significant differences within the GDM group according to treatment type, except for higher heart rate in women treated with metformin alone compared to the group treated with diet alone. Women with GDM and those with pre-existing DM have evidence of early vascular disease in the third trimester, and this may contribute to their increased long-term cardiovascular risk. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Prevalence and Antimicrobial Susceptibility Patterns of Wound and Pus Bacterial Pathogens at a Tertiary Care Hospital in Central Riyadh, Saudi Arabia

The long history and extensive use of antibiotics have caused resistant bacterial pathogens to emerge, increasing mortality and morbidity. The current study was designed to see the prevalence of aerobic bacterial isolates with their antimicrobial resistance pattern from out- and inpatients requested for wound or pus culture. Retrospective study conducted at a tertiary care hospital in central Riyadh from January 2023 to December 2023. Samples were collected and inoculated onto the appropriate media following standard guidelines. Bacterial pathogens were identified by the Vitek2 compact system. Antimicrobial susceptibility was tested using the Kirby–Bauer disk diffusion method as well as by MIC determination through the Vitek2 compact. A total of 1186 subjects were included in the study with a bacterial isolation rate of 691 (58.3%). Out of these, 155 positive cultures had incomplete information or anaerobic or fungal growth and were excluded from the study. With a slight female predominance (54.9%), the majority of subjects (72.2%) were outpatients, and over half of the isolates (55.2%) were Gram-positive. The most common isolate was Staphylococcus spp. (44.4%), followed by E. coli (13.6%) and P. aeruginosa (12.9%). The highest resistance was reported against penicillin followed by fusidic acid against Gram-positive bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 40.5% of Staphylococcus aureus (S. aureus) isolates. Amikacin was the most susceptible antibiotic against all Gram-negative isolates. MDR Gram-negative bacteria accounted for 51.9% of wound infection isolates (95% CI: 45.95 to 58.33) while 6.3% (95% CI: 4.39 to 8.86) were XDR (nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories). A high prevalence of bacterial isolates, with S. aureus as the predominant pathogen, showed high rates of multidrug resistance. This highlights the importance of monitoring antibiotic choices for prophylaxis and treatment in the study area.

A-290 Prevalence and Antimicrobial Resistance Pattern of Microorganisms Recovered From Bloodstream Infections From Public Hospitals of São Paulo City, Brazil

Abstract Background Nosocomial Bloodstream Infections (nBSI) are an important cause of morbidity and mortality. Brazilian studies concerning bloodstream infections are important tools that can bring specific issues related to antimicrobial resistance. The objective of this study was to describe the frequency and antimicrobial susceptibility profile of bacterial isolates from BSI in patients admitted to public hospitals in 2022 and 2023. Methods This study was a retrospective analysis from 12 hospitals (January 2022 to December 2023) based on BSI isolates laboratory data detected by the clinical microbiology department of a medical diagnostic laboratory. The identification and susceptibility tests were performed using MALDI-TOF mass spectrometry (Vitek MS) and Vitek®2 systems, according to the manufacture’s recommendations. Coagulase Negative Staphylococci (CoNS) BSI was only considered in the presence of at least two sets of positive blood cultures with the same organism. Results During the period (January 2022 to December 2023) a total of 19,588 microorganisms isolated from BSI were obtained from 12 hospitals. The frequency of organism group was Gram-positive (10,707; 54.7%), Gram-negative (7,874; 40.2%), yeasts (961; 4.9%) and filamentous (46; 0.2%). The order of prevalence (top ten) organisms was CoNS (5,149; 26.3%); Staphylococcus aureus (2,769; 14.1%); Klebsiella spp. (2,355; 12.0%); Escherichia coli (1,301; 6.6%); Acinetobacter spp. (1,293; 6.6%); Streptococcus spp. (1,125; 5.7%); Enterococcus spp. (1,112; 5.7%); Candida spp. (937; 4.8%); Pseudomonas spp. (749; 3.8%) and Proteus spp. (553; 2.8%). Extended spectrum beta-lactamase rates for E. coli and Klebsiella pneumoniae were 31.6% (268/848) and 74.9% (1027/1371), respectively. The resistance to carbapenems was detected mainly in 74.1% (661/892) of Acinetobacter spp. isolates, 60.7% (832/1371) of Klebsiella pneumoniae; 24.5% (114/465) of P. aeruginosa; 9.7% (34/349) of Proteus spp. and 1.4% (12/828) of Escherichia coli. Antimicrobial resistance was observed mainly in 87.2% of CoNS (2831/3247) and 44.5% of S. aureus (743/1669) to methicillin; 22.9% (146/637) of Enterococccus spp. to vancomycin. Conclusions The frequency of Klebsiella spp. isolates from nBSI has progressively increased and effective infection control measures should be taken to prevent them from spreading. The rates of antimicrobials resistance reported for Klebsiella pneumoniae, Acinetobacter spp., CoNS, S. aureus and Enterococcus spp. reinforce the high resistance rates to antimicrobials in São Paulo city.

Genome characterization of Shewanella algae in Hainan Province, China.

Shewanella algae is an emerging marine zoonotic pathogen. In this study, we first reported the Shewanella algae infections in patients and animals in Hainan Province, China. Currently, there is still relatively little known about the whole-genome characteristics of Shewanella algae in most tropical regions, including in southern China. Here, we sequenced the 62 Shewanella algae strains isolated from Hainan Province and combined with the whole genomes sequences of 144 Shewanella algae genomes from public databases to analyze genomic features. Phylogenetic analysis revealed that Shewanella algae is widely distributed in the marine environments of both temperate and tropical countries, exhibiting close phylogenetic relationships with genomes isolated from patients, animals, and plants. Thereby confirming that exposure to marine environments is a risk factor for Shewanella algae infections. Average nucleotide identity analysis indicated that the clonally identical genomes could be isolated from patients with different sample types at different times. Pan-genome analysis identified a total of 21,909 genes, including 1,563 core genes, 8,292 strain-specific genes, and 12,054 accessory genes. Multiple putative virulence-associated genes were identified, encompassing 14 categories and 16 subcategories, with 171 distinct virulence factors. Three different plasmid replicon types were detected in 33 genomes. Eleven classes of antibiotic resistance genes and 352 integrons were identified. Antimicrobial susceptibility testing revealed a high resistance rate to imipenem and colistin among the strains studied, with 5 strains exhibiting multidrug resistance. However, they were all sensitive to amikacin, minocycline, and tigecycline. Our findings clarify the genomic characteristics and population structure of Shewanella algae in Hainan Province. The results offer insights into the genetic basis of pathogenicity in Shewanella algae and enhance our understanding of its global phylogeography.

Investigating the feasibility and potential of combining industry AMR monitoring systems: a comparison with WHO GLASS.

Efforts to estimate the global burden of antimicrobial resistance (AMR) have highlighted gaps in existing surveillance systems. Data gathered from hospital networks globally by pharmaceutical industries to monitor antibiotic efficacy in different bacteria represent an underused source of information to complete our knowledge of AMR burden.. We analysed available industry monitoring systems to assess to which extent combining them could help fill the gaps in our current understanding of AMR levels and trends. We analysed six industry monitoring systems (ATLAS, GEARS, SIDERO-WT, KEYSTONE, DREAM, and SOAR) obtained from the Vivli platform and reviewed their respective isolates collection and analysis protocols. Using the R software, we designed a pipeline to harmonise and combine these into a single dataset. We assessed the reliability of resistance estimates from these sources by comparing the combined dataset to the publicly available subset of WHO GLASS for shared bacteria-antibiotic-country-year combinations. Combined, the industry monitoring systems cover 18 years (4 years for GLASS), 85 countries (71), 412 bacterial species (8), and 75 antibiotics (25). Although all industry systems followed a similar centralised testing approach, the patient selection protocol and associated sampling period were unclear. Over all reported years and countries, E.coli, K. pneumoniae and S. aureus resistance rates were in >65% of cases within 0.1 of the corresponding estimate in GLASS. We did not identify systemic bias towards resistance in industry systems compared to GLASS. High agreement values for available comparisons with GLASS suggest that data for other bacteria-antibiotic-country-year combinations only present in industry systems could complement GLASS; however, for this purpose patient and isolate selection criteria must first be clarified to understand the representativeness of industry systems. This additional source of information on resistance levels could help clinicians and stakeholders prioritize testing and select appropriate antibiotics in settings with limited surveillance data.

A-254 Increase of Stenotrophomonas maltophilia Isolates Non-Susceptible to Trimethoprim-Sulfamethoxazole and/or Levofloxacin at Brazilian Hospitals

Abstract Background Stenotrophomonas maltophilia is an emerging multidrug-resistant pathogen that exhibits intrinsic and acquired resistance to a wide variety of antimicrobial agents such as β-lactams, aminoglycosides, quinolone, tetracyclines and disinfectants. In addition to that, the increased resistance to sulfamethoxazole/trimethoprim (SMX/TMP) and Levofloxacin has been reported in the past few years, leading to few therapeutic options. This study aimed to describe the increase of Stenotrophomonas maltophilia clinical isolates recovered from Brazilian hospitals over a 6-year analysis (January 2018 to December 2023). Methods This study design was a retrospective, observational analysis based on microbiological data of emergent BGN-NF isolates detected in several Brazilian tertiary hospitals. The bacterial identification was performed by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF/MS) and the antimicrobial susceptibility profile to trimethoprim-sulfamethoxazole and levofloxacin was determined using disk-diffusion method and epsilometer method, respectively. Only one sample per patient was considered in this analysis. Results During the 6 year period, a total of 1,706 (2018; 221), (2019; 203), (2020; 294), (2021; 276), (2022; 294) and (2023; 418) Stenotrophomonas maltophilia strains were isolated from blood (n=626), respiratory tract (n=365), fluid and secretion (n=235), skin and soft tissue (n=162), urine (n=132), catheter tip (n=112), swab (n=36), bone fragment (n=29) and cerebrospinal fluid (n=9). The major frequency of S. maltophilia isolation occurred among man (52.6%) and the main age range was over 60 years (42.7%), while 0-10 comprised 16.6% of cases. Compared the 6-years period, the resistance rate to trimethoprim-sulfamethoxazole was 2.7%; 5.4%; 5.8%; 2.2%; 5.8%; 7.9% and levofloxacin was 3.6%; 3.4%; 3.1%; 3.3%; 1.7%; 2.9%, respectively. The resistance rate to trimethoprim-sulfamethoxazole and levofloxacin, simultaneously, was 0.23%. Conclusions The incidence rate of S. maltophilia infections has increased significantly, especially in the last year, followed by an increase in the pattern of resistance to trimethoprim-sulfamethoxazole. Regarding trimethoprim-sulfamethoxazole and levofloxacin co-resistance, very low rates were detected in our analysis. Our data point to a scenario wherein the presence of S. maltophilia may have been intensified by the covid-19 pandemic. Regional surveillance reports are extremely important and should be out to understand some aspects of the dynamics of bacterial resistance in both hospital and community settings.

Genetic Determinants of Clarithromycin and Fluoroquinolones Resistance in Helicobacter pylori in Serbia.

Stomach infections by Helicobacter pylori can cause acute or chronic gastritis, peptic ulcers, and gastric cancer. The rise in antibiotic resistance is a significant health issue highlighted by the World Health Organization. The increasing number of treatment failures underscores the necessity for antibiotic susceptibility testing (AST). The study aimed to investigate the current prevalence and resistance to fluoroquinolones and clarithromycin with their detected mutations. Stomach biopsies from symptomatic patients were subjected to molecular testing by GenoType Helico DR kit (Hain Lifescience GmbH, Nehren, Germany). Positive findings on the presence of H. pylori were detected in 42.4% of symptomatic patients, with the significant majority of patients (69%) having previously failed treatments. The resistance rates to fluoroquinolones and clarithromycin were 53.9% and 58.5%, respectively, with significantly higher rates in secondary resistant strains. The main resistance markers in fluoroquinolones and clarithromycin were N87K (27.4%) and A2147G (78.6%), respectively. Hetero-resistance or mixed genotypes were detected in over 20% of tested patients. During the study period, a significant increase in trends in both fluoroquinolones and clarithromycin resistance rates was observed. Results indicate the need for the implementation of the latest Maastricht VI Consensus recommendations for both AST whenever possible and the use of tailored guided therapy options due to high resistance rates and possible treatment failures. The GenoType Helico DR kit is a useful tool for AST, especially in cases of mixed H. pylori genotypes.

Antibiotic Resistance in Morganella morganii Species: Mechanisms, Prevalence and Clinical Implication

: Morganella morganii, a member of the Enterobacteriaceae family, has gained increasing recognition as an important pathogen due to its multidrug resistance. In addition to its intrinsic resistance, it carries various resistance genes and mobile genetic elements, facilitating the spread of resistance genes. M. morganii develops its mechanisms of resistance through different genetic elements, and its pathogenicity is supported by several virulence factors. Its rate of resistance has attended high levels in a number of studies. The global prevalence of M. morganii-associated infections is observed with nosocomial and healthcare-associated infections. The spectrum of diseases caused by M. morganii is diverse, ranging from sepsis and urinary tract infections, abscess, purple urine bag syndrome, chorioamnionitis, and cellulitis to wound infections and bacteremia. Mortality rates associated with M. morganii infections remain high, emphasizing the need for effective treatment strategies. Thus, this article aimed to provide an overview of the evolving multidrug resistance, resistance genes, risk factors, spectrum diseases, and clinical significance of M. morganii, and the challenges associated with the diagnosis and treatment of M. morganii infections.

Candida auris MIC testing by EUCAST and clinical and laboratory standards institute broth microdilution, and gradient diffusion strips; to be or not to be amphotericin B resistant?

ObjectivesReported amphotericin B resistance rates for Candida auris vary considerably. This may reflect clinically relevant differences in susceptibility, technical issues with testing, or adoption of a clinical breakpoint that bisects the wild-type population. We compared reference methods and two gradient diffusion strips using a shared C. auris strain collection. MethodsForty C. auris strains from nine U.S. states and ≥3 clades were included. Fourteen MIC data sets were generated using EUCAST E.Def 7.4, Clinical and Laboratory Standards Institute (CLSI) M27Ed4, Etest, and MTS (Liofilchem) strip MICs. MICs ≤1 mg/L were classified as susceptible. ResultsEUCAST and CLSI amphotericin B MIC testing were robust across the included method variables. The modal MIC was 1 mg/L, distributions unimodal and narrow with similar GM-MICs (0.745–1.072); however, susceptibility classification varied (0–28% resistance). Gradient diffusion strip testing resulted in wider and bimodal distributions for 8/9 data sets. If adopting, per manufacturer's protocol, double inoculation for the Etest method, the modal MIC increased to 2–4 mg/L and resistance rates to 45–63% versus 25–30% with the single inoculation. The EUCAST, CLSI, Etest, and MTS strip MICs correlated to the optical density of drug-free control EUCAST wells, suggesting that some isolates grew better than others and that this was associated with MIC. Discussion: The EUCAST and CLSI MIC results were in close agreement, whereas the strip test showed wider and bimodal distributions with reader to reader and centre to centre variation. Our study adds to the concern for commercial MIC testing of amphotericin B against C. auris and suggests the current breakpoint leads to random susceptibility classification.