Search Results (196)

We analyzed the whole genome sequences (WGS) and antibiograms of 35 Enterobacter isolates, including E. hormaechei and E. asburiae, and the recently described E. bugandensis, E. kobei, E. ludwigii, and E. roggenkampii species. Isolates were obtained from human blood and urinary tract infections in patients in the United States. Our goal was to understand the genetic diversity of antimicrobial resistance genes and virulence factors among the various species. Thirty-four of 35 isolates contained an AmpC class bla_ACT allele; however, the E. roggenkampii isolate contained bla_MIR-5. Of the six Enterobacter isolates resistant to ertapenem, imipenem, and meropenem, four harbored a carbapenemase gene, including bla_KPC or bla_NDM. All four isolates were mCIM-positive. The remaining two isolates had alterations in ompC genes that may have contributed to the resistance phenotype. Interpretations of cefepime test results were variable when disk diffusion and automated broth microdilution results were compared due to the Clinical Laboratory and Standards Institute use of the “susceptible dose-dependent” classification. The diversity of the bla_ACT alleles paralleled species identifications, as did the presence of various virulence genes. The classification of recently described Enterobacter species is consistent with their resistance gene and virulence gene profiles. Full article

Understanding the epidemiology of mecA-positive Staphylococcus pseudintermedius strains, including those that are oxacillin-susceptible but potentially inducible to resistance, is crucial for developing effective treatment strategies and mitigating public health risks. This study characterized 87 mecA-positive S. pseudintermedius isolates obtained from skin lesions and nasal orifices of 46 dogs with pyoderma enrolled at a referral hospital in Thailand between 2019 and 2020. All isolates underwent antibiogram profiling, SCCmec typing, and pulsed-field gel electrophoresis (PFGE) for phenotypic and genetic analysis. Among the 87 isolates, 33 isolates (37.9%) recovered from 15 dogs were oxacillin-resistant (OR-MRSP), while 54 isolates (62.1%) from 31 dogs were oxacillin-susceptible (OS-MRSP). All OR-MRSP isolates exhibited multidrug resistance (MDR), and 44% of the OS-MRSP isolates also showed MDR. SCCmec typing revealed type V as predominant among OR-MRSP isolates (69.7%), while many oxacillin-susceptible isolates (70.4%) were non-typeable. The OR-MRSP isolates from the same dog showed consistent antibiogram and SCCmec types, while OS-MRSP isolates displayed both identical and diverse patterns. No dominant pulsotypes were observed among the OR-MRSP or OS-MRSP strains. Genetic diversity was also noted among the isolates within the same dogs and among the others, highlighting the complexity of S. pseudintermedius colonization and infection dynamics in pyoderma-affected dogs. Full article

Background. Pseudomonas aeruginosa is one of the major concerns among bacterial diseases even when it shows a wild-type susceptibility pattern. In 2020, EUCAST reconsidered antibiogram interpretation shifting “I” from “intermediate” to “sensible, increased exposure” with possible significant impact on antibiotic prescription. The aim of this study was to evaluate mortality in patients with P. aeruginosa bloodstream infections treated with antipseudomonal penicillins or cephalosporins vs. carbapenems and ceftazidime/avibactam. Methods. This is a retrospective observational study. All the patients with a bloodstream infection due to P. aeruginosa admitted to our hospital were enrolled. Exclusion criteria were as follows: extremely critical conditions, age <18 years, pregnancy, isolation of a strain non-susceptible to piperacillin/tazobactam and antipseudomonal cephalosporins. Patients were divided into group A (treatment with carbapenems or ceftazidime/tazobactam) and group B (treatment with antipseudomonal penicillin or cephalosporins). Results. We enrolled 77 patients, 56 and 21 in groups A and B, respectively. The two groups were homogeneous for age, sex, and biochemical and clinical characteristics at admission. All-cause in-hospital mortality was 17/56 (30.4%) and 3/21 (14.3%) in groups A and B, respectively (p > 0.1). In group A, in-hospital BSI-related mortality was 23.2% (13/56), while it was 14.3% (3/21) in group B (p > 0.1). After multivariate analysis, only the PITT score represented a risk factor for BSI-related mortality (OR 2.917, 95% CI 1.381–6.163). Conclusions. Both all-cause and BSI-related mortality were comparable between the two groups. Treatment with carbapenem or ceftazidime/avibactam did not represent a protective factor for mortality in wild-type P. aeruginosa BSI. Full article

The existence of fecal coliform microorganisms (FCs) resistant to antibiotics in the domestic wastewater of an urban and semi-urban locality was determined, along with the effect of two types of treatment plants for wastewater on the resistance of coliform, an aerated lagoon (AL) and a stabilization lagoon (SL). Samples were taken from the affluent and effluent of each treatment plant. FC content, pH, electrical conductivity, dissolved oxygen, total solids, total volatile solids, and several types of ions were determined. Resistant FCs were quantified by plate count in bright green bile agar with ampicillin, amoxicillin, sulfamethoxazole-trimethoprim, amikacin, gentamicin, cefixime and their mixtures. The isolated strains were evaluated against other antibiotics using antibiograms. The relationship between the variables was validated with an analysis of variance factorial design, and Fisher’s means test (α = 0.05) and Pearson’s correlation were used to establish it. The community that presented more resistant FCs was the urban one, but when the wastewater passed through the systems of AL and SL, this fact changed. The resistance of the FCs to ampicillin, amoxicillin, trimethoprim, sulfamethoxazole and cefixime was higher in the SL, with values of 67, 48, 2 and 25.8%, while those for the AL were 20, 13, 22 and 5.3%, respectively. Full article

Background: Typhoid fever caused by Salmonella enterica serovar Typhi (S. typhi) continues to pose a significant risk to public health in developing countries, including Pakistan. This study investigated the epidemiological factors linked to suspected and confirmed S. typhi infections in Peshawar’s hospital population. Methodology: A total of 5735 blood samples of patients with suspected enteric fever were collected from September 2022 to November 2023. S. typhi infection was confirmed using microbiological culture of blood samples, biochemical-based tests, and DNA-sequencing methods. Drug sensitivity testing on cultures was conducted as per the CLSI guidelines. Chi-square tests were used to analyze the clinical and epidemiologic characteristics of 5735 samples stratified by S. typhi infection status, and risk factors were assessed by applying logistic regression models to estimate odds ratios (ORs). Results: The number of confirmed typhoid fever cases in this hospital-based study population was 691 (/5735, 12.0%), more prevalent in males (447/3235 13.8%) and children (0–11 years) (429/2747, 15.6%). Compared to children, the risk of S. typhi infection was lower in adolescence (adjusted OR = 0.52; 95% CI: 0.42–0.66), adulthood (19–59 years; aOR = 0.30; 95% CI: 0.25–0.38), and older adulthood (aOR = 0.08; 95% CI: 0.04–0.18) (p < 0.001). Compared to males, the risk of S. typhi infection was lower in females (aOR = 0.67; 95% CI = 0.56–0.80; p = 0.002). Living in a rural residence (compared to urban) was associated with a higher risk of infection (aOR = 1.38; 95% CI: 1.16–1.63; p = 0.001), while access to a groundwater source (compared to municipal water supply) led to a lower risk (aOR = 0.56; 95% CI: 0.43–0.73; p = 0.002). Vaccination demonstrated a robust protective effect (aOR = 0.069; 95% CI = 0.04–0.11, p = 0.002). For those with typhoid infections, clinical biomarker analysis revealed the presence of leucopenia (65/691, 9.4%), thrombocytopenia (130/691, 18.8%), and elevated alanine aminotransferase (ALT) (402/691, 58.2%) and C-reactive protein (CRP) (690/691, 99.9%) levels. Worryingly, among the positive S. typhi isolates, there was a high prevalence of drug resistance (653/691), including multidrug-resistant (MDR 82/691, 11.9%) and extensively drug-resistant types (XDR, 571/691, 82.6%). Conclusions: This study highlights the importance of age, sex, locality, water source, and vaccination status in shaping the epidemiological landscape of S. typhi in the Peshawar district. It implies that expanding vaccination coverage to the broader population of Khyber Pakhtunkhwa province, particularly in the district of Peshawar, would be beneficial. Full article

Knowledge of epidemiology is essential for guiding correct antibiotic prescription, reducing bacteremia-associated mortality, and implementing targeted infection control programs. However, only a few studies have reported on the epidemiology of bloodstream infections (BSIs) in pediatrics. We performed a retrospective analysis of all BSIs (excluding those caused by common skin contaminants) diagnosed from 2006 to 2022 in patients younger than 18 years who were treated at an Italian pediatric tertiary care hospital. Overall, 2395 BSIs were recorded, including 2207 (92.15%) due to bacteria and 188 (7.85%) due to fungi. The incidence rate (BSIs/10,000 hospital discharges, IR) of bacterial BSIs significantly increased during the study period. In particular, BSIs caused by S. aureus (including MRSA), Enterobacterales (including ESBL and AmpC producers), Enterococcus spp., and P. aeruginosa became more common. The frequency of carbapenem-resistant strains was <1% and stable over time. Conversely, there was a significant reduction in the incidence of BSIs due to S. pneumoniae. The BSIs were stratified by patient age, and S. aureus was the most frequent cause of BSIs in all age groups, while E. coli was the most frequent in the Enterobacterales family. S. agalactiae was the third most frequent cause of neonatal early-onset BSIs. The prevalence of Enterococcus spp. increased in the subgroups from 8 days to 5 years of age, while P. aeruginosa became more prevalent in children over 5 years of age. S. aureus was also the most frequent isolate in both community- and hospital-onset BSIs, followed by E. coli. The prevalence of multidrug-resistant (MDR) pathogens was very low. It was <5% for both Gram-positive (i.e., MRSA and VRE) and Gram-negative (ESBL, AmpC, and carbapenem-resistant) pathogens, and MDR pathogens were almost exclusively detected in hospital-onset BSIs. Fungi accounted for just under 8% of BSIs. C. albicans was the most frequently isolated strain, followed by C. parapsilosis. Notably, the IR of fungemia did not change significantly during the study period, in spite of an increase in the absolute number of events. The continuous monitoring of local epidemiology is essential to identify changes in the IRs of pathogens and antibiotic susceptibility and to guide antibiotic treatments, especially in the phase when antibiograms are not yet available. Full article

Enterobacterales resistant to extended-spectrum cephalosporins (ESC) are a marker of the antimicrobial resistance (AMR) burden. They are infecting humans, but the intestinal microbiota can also be transiently colonized without developing symptoms. Healthy carriage can promote silent dissemination of resistant bacteria, and data on this colonization are often lacking. Between 2021 and 2023, a sampling of healthy Tunisian people was carried out. Fecal samples (n = 256) were plated on selective agar, and all collected isolates were characterized by phenotypic (antibiograms) and genomic (whole-genome sequencing) methods. A total of 26 (26/256, 10.2%) isolates were collected, including 24 Escherichia coli and 2 Klebsiella pneumoniae. In total, 17 isolates (15 E. coli and 2 K. pneumoniae) presented an ESBL phenotype conferred by the bla_CTX-M-15 gene, and 9 E. coli isolates presented an AmpC phenotype conferred by the bla_DHA-1 gene. K. pneumoniae belonged to ST1564 and ST313, while E. coli belonged to diverse STs including the pandemic ST131 clone. Clonally related ST349 E. coli isolates carrying the bla_DHA-1 gene were found in nine individuals. In parallel, four bla_CTX-M-15 -positive E. coli isolates carried this ESC-resistance gene on an epidemic plasmid IncF/F-:A-:B53 previously identified in Tunisian pigeons and fish. These findings highlight the spread of genetically diverse ESC-resistant Enterobacterales as well as an epidemic plasmid in Tunisia, emphasizing the need for antimicrobial stewardship to limit the transmission of these resistances in the Tunisian population. Full article

Background/Objectives: Antibiotic (AB) therapy is the first step in managing hidradenitis suppurativa (HS). Knowledge of the local patterns of antimicrobial resistance is paramount for the appropriate selection of antimicrobials. This study aimed to assess the occurrence of antibiotic resistance in patients with HS. Methods: A cross-sectional study was conducted on 103 patients with HS seen at the Dermatology Department at the University Hospital of Heraklion, Heraklion, Crete, Greece, from January 2019 to December 2023, who were not on any antibiotics in the last three months. Results: A total of 103 patients with HS participated in this study. Purulent material from 139 skin lesions of these patients was swabbed, and 79.86% (111/139) tested positive for bacteria. Gram-positive isolates accounted for 73%, whereas Gram-negative isolates comprised 27%. Among the isolates, 85.1% were aerobes, and 14.9% were anaerobic. The most common bacterial families isolated were Staphylococcaceae (48.27%), Enterobacteriaceae (14.94%), and Streptococcaceae (6.89%). The antibiogram profiles of bacterial cultures revealed a 57.1% resistance to levofloxacin and a 53.3% resistance to penicillin in Staphylococcus lugdunensis, whereas Staphylococcus aureus showed a 76.9% resistance to penicillin and a 58.3% resistance to fusidic acid. High resistance rates of 63.5% for tigecycline, 63.3% for ampicillin, and 40.5% for colistin were observed for Gram-negative isolates. Resistances of 62.5%, 61.5%, and 53.8% to erythromycin, clindamycin, and penicillin, respectively, were observed in the anaerobes. Conclusions: Patients with HS displayed considerable resistance to bacterial proliferation. The revised therapeutic guidelines for HS should incorporate the latest insights into bacterial antibiotic resistance. Full article

Current antibiograms cannot discern the particular effect of a specific antibiotic when the bacteria are incubated with a mixture of antibiotics. To prove that this task is achievable, Escherichia coli strains were treated with ciprofloxacin for 45 min, immobilized on a slide and stained with SYBR Gold. In susceptible strains, the nucleoid relative surface started to decrease near the MIC, being progressively condensed as the dose increased. The shrinkage level correlated with the DNA fragmentation degree. Ciprofloxacin-resistant bacilli showed no change. Additionally, E. coli strains were incubated with ampicillin for 45 min and processed similarly. The ampicillin-susceptible strain revealed intercellular DNA fragments that increased with dose, unlike the resistant strain. Co-incubation with both antibiotics revealed that ampicillin did not modify the nucleoid condensation effect of ciprofloxacin, whereas the quinolone partially decreased the background of DNA fragments induced by ampicillin. Sixty clinical isolates, with different combinations of susceptibility-resistance to each antibiotic, were co-incubated with the EUCAST breakpoints of susceptibility of ciprofloxacin and ampicillin. The morphological assay correctly categorized all the strains for each antibiotic in 60 min, demonstrating the feasible independent evaluation of a mixture of quinolone and beta-lactam. The rapid phenotypic assay may shorten the incubation times and necessary microbial mass currently required for evaluation. Full article

Staphylococcus argenteus, identified in 2006, represents a challenging case of bacterial taxonomic identification because of its high similarity to Staphylococcus aureus. In this context, neither mass spectrometry (MS) nor 16S gene analysis cannot precisely reveal the difference between the two species. In our study, the sensitivity to antibiotics of S. argenteus isolated from blood culture was tested, and the investigation of the bacterial genome was performed by Multi-Locus Sequence Typing (MLST) and Whole-Genome Next-Generation Sequencing (WG-NGS). The pathogen was identified as ST2250 and presented perfectly matched resistance genes, namely aph(3′)-III, mgrA, and sepA, whereas the virulence gene detected was scn. Two plasmids were found: the pSAS plasmid, belonging to the family of Inc18, and plasmid pN315, belonging to the Rep3 group. The epidemiological distribution and the spread of S. argenteus infection are scarcely documented, particularly when associated with sepsis. Therefore, a correct taxonomy identification, antibiogram, and resistance gene analysis may help in acquiring knowledge about this bacterium and implement its detection and treatment. Full article

Carbapenem-resistant Pseudomonas aeruginosa infections represent a critical public health concern, highlighting the need for the development of effective antibiotics. Cefiderocol demonstrated potent in vitro activity against Pseudomonas aeruginosa, particularly in strains that are resistant to other drugs. However, concerns regarding the emergence of drug-resistant strains persist. This study, conducted with 109 carbapenem-resistant Pseudomonas aeruginosa strains from the Spanish Hospital (Dr. Balmis, Alicante). The study evaluated susceptibility to cefiderocol in comparison to alternative antibiotics and including their susceptibility to bacterial inoculum, while assessing various testing methods. Our findings revealed high susceptibility to cefiderocol against carbapenem-resistant strains, with only 2 of 109 strains exhibiting resistance. Comparative analysis demonstrated superiority of cefiderocol towards alternative antibiotics. Both the E-test and disk-diffusion methods showed 100% concordance with the microdilution method in classifying strains as susceptible or resistant. However, 4.6% (5/109) of disc zone diameters fell within the technical uncertainty zone, so the E-test technique was found to be more useful in routine clinical practice. Additionally, escalating bacterial inoculum correlated with decreases in vitro activity, so this parameter should be adjusted very carefully in in vivo studies. This study underscores cefiderocol’s potential as a therapeutic option for carbapenem-resistant Pseudomonas aeruginosa infections. However, the emergence of drug-resistant strains emphasizes the critical need for a wise use of antibiotics and a continuous monitoring of resistance to antibiotics. Based on our in vitro data, further investigation concerning the impact of bacterial inoculum on drug efficacy is warranted in order to detect resistance mechanisms and optimize treatment strategies, thereby mitigating the risk of resistance. Full article

Antibiotic resistance is a significant global health issue, exacerbated by the indiscriminate use of antibiotics without antibiograms. Implementing appropriate stewardship programs that monitor and control antibiotic use is essential to minimize resistance development and ensure optimal patient outcomes. This study aims to assess the impact of antibiogram availability and utilization on antibiotic use among healthcare providers in Saudi Arabia, focusing on whether antibiogram data and utilization influence the appropriateness of antibiotic prescribing practices. A cross-sectional study design was employed, utilizing a self-administered online survey distributed to physicians, pharmacists, and other healthcare providers across various healthcare settings in Saudi Arabia. Data were collected over a 90-day period, from 1 December 2023 to 29 February 2024. Descriptive statistics were used to summarize participants’ characteristics, and data were analyzed based on geographical region, participants’ positions, and other predetermined differences. Out of 23,860 contacted individuals, 333 responded, and 283 were included in the analysis. The majority (62.2%) reported the availability of antibiograms at their facilities, with 84.1% utilizing them in clinical practice. The frequency of consulting antibiograms varied, with only 21.6% doing so daily. Key barriers to antibiogram availability included lack of expertise, technological infrastructure, and funding. Most participants (68.8%) observed changes in antibiotic prescription practices post-antibiogram introduction, and 86.9% believed antibiograms could shorten patients’ length of stay and improve outcomes. However, only 40.9% had received training on antibiogram use. While healthcare providers in Saudi Arabia have a relatively high level of antibiogram availability and utilization, several barriers hinder their consistent use. Enhancing accessibility, promoting frequent use, and providing targeted training could strengthen the impact of antibiograms on antibiotic prescribing practices and antimicrobial stewardship efforts. Full article

Background. The management of odontogenic infections varies across the globe. To shed light on the subject, this study delves into the practices of the Oral and Maxillofacial Department at Cluj-Napoca County Hospital. Material and Methods. This comprehensive retrospective analysis of 10 years of clinical experience covered a range of factors, including demographics, clinical and investigations factors, medical and surgical treatment approaches, and follow-up. Additionally, the study examined the change in trends over the course of the COVID-19 pandemic. Results. While head and neck infection occurrence had a decreasing trend before the COVID-19 pandemic, during the pandemic era the number of patients almost doubled. The infections were prevalent in the submandibular space, teeth being the prevalent cause. Young adults are prone to suffer from odontogenic infections. High levels of C reactive protein, ASA II-IV risk, and hepatic dysfunction indicated a longer time of hospitalization. The majority of antibiograms were negative, and the positive ones indicated Streptococcus and Staphylococcus species as prevalent pathogens. Extra- or intraoral surgical drainage and wide-spectrum antibiotics proved to be the workhorse for odontogenic infections. Conclusion. This study advances our understanding of oral and maxillofacial surgery and offers actionable strategies for improving patient outcomes in similar healthcare institutions worldwide. Full article

The present study aims to evaluate the antibacterial activity of five commercially available essential oils (EOs), Lavender (LEO), Clove (CEO), Oregano (OEO), Eucalyptus (EEO), and Peppermint (PEO), against the most-known MDR Gram-positive and Gram-negative bacteria—Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853)—alone and in various combinations. Gas Chromatography–Mass Spectrometry (GC-MS) analysis established their complex compositions. Then, their antibacterial activity—expressed as the inhibition zone diameter (IZD) value (mm)—was investigated in vitro by the diffusimetric antibiogram method, using sterile cellulose discs with Ø 6 mm impregnated with 10 µL of sample and sterile borosilicate glass cylinders loaded with 100 µL; the minimum inhibitory concentration (MIC) value (µg/mL) for each EO was calculated from the IZD values (mm) measured after 24 h. The following EO combinations were evaluated: OEO+CEO, CEO+EEO, CEO+PEO, LEO+EEO, and EEO+PEO. Then, the influence of each dual combination on the activity of three conventional antibacterial drugs—Neomycin (NEO), Tetracycline (TET), and Bacitracin (BAC)—was investigated. The most active EOs against S. aureus and E. coli were LEO and OEO (IZD = 40 mm). They were followed by CEO and EEO (IZD = 20–27 mm); PEO exhibited the lowest antibacterial activity (IZD = 15–20 mm). EEO alone showed the highest inhibitory activity on P. aeruginosa (IZD = 25–35 mm). It was followed by CEO, LEO, and EEO (IZD = 7–11 mm), while PEO proved no antibacterial action against it (IZD = 0 mm). Only one synergic action was recorded (OEO+CEO against P. aeruginosa); EEO+PEO revealed partial synergism against S. aureus and CEO+PEO showed additive behavior against E. coli. Two triple associations with TET showed partial synergism against E. coli, and the other two (with NEO and TET) evidenced the same behavior against S. aureus; all contained EEO+PEO or CEO+PEO. Most combinations reported indifference. However, numerous cases involved antagonism between the constituents included in the double and triple combinations, and the EOs with the strongest antibacterial activities belonged to the highest antagonistic combinations. A consistent statistical analysis supported our results, showing that the EOs with moderate antibacterial activities could generate combinations with higher inhibitory effects based on synergistic or additive interactions. Full article

Antimicrobial susceptibility tests, achieved through the use of antibiotic-impregnated disks in a suitable laboratory environment, are conducted to determine which antibiotics are effective against the bacteria present in the body of an infected patient. The Kirby–Bauer method, a type of disk diffusion antimicrobial susceptibility test, is currently widely applied in microbiology laboratories due to its proven effectiveness. In our study, we developed an algorithm that utilizes image processing techniques to detect the inhibition zones of bacteria. A certain color depth acts as the threshold for the inhibition zone, with its radius determined according to the size of the reference object. This approach facilitates the measurement of inhibition zones and employs machine learning and deep learning to categorize antibiograms, followed by determination of whether a bacterium on the disk is sensitive or resistant to the antibiotics applied. The focus of this research is creating an automated interpretation system for antimicrobial susceptibility testing using the disk diffusion technique, thus simplifying the measurement and interpretation of inhibition zone sizes. Full article