Methicillin-resistant Staphylococci Research Articles

Nasal microbiota predictors for methicillin resistant Staphylococcus colonization in critically ill children.

Surveillance cultures to identify patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) is recommended at pediatric intensive care unit (PICU) admission but doesn't capture other methicillin-resistant Staphylococcus and is resource intensive. We determined the prevalence and identified nasal microbiome predictors for methicillin-resistant Staphylococcus colonization at the time of PICU admission. A prospective cohort study was performed in a 20-bed pediatric intensive care unit (PICU) between 2020-2021. Anterior nares nasal swabs processed for MRSA culture, nasal microbiome and mecA+ qPCR were obtained within first five days after PICU admission. Predictive values of methicillin-resistant Staphylococcus carriage on symptoms of infection and for nasal microbiome attributes were calculated. A total of 5 (8.0%) of 62 patients had a nares culture positive for MRSA and 22 (35.5%) of 63 patients had methicillin-resistant Staphylococcus (MRSA or methicillin-resistant coagulase-negative Staphylococci). In univariate analysis, carriage with MRSA or MRCoNS was associated with having a fever during PICU stay. Colonization with a distinct set of microbes (including Haemophilus, Streptococcus, Prevotella and Corynebacterium sp.) was predictive of having methicillin-resistant Staphylococcus colonization. Carriage with methicillin-resistant Staphylococcus may lead to transmission in critically ill pediatric patients. Carriage of particular nasal microbes appears to facilitate colonization with methicillin-resistant Staphylococcus.

Molecular Epidemiological Characteristics of Staphylococcus pseudintermedius, Staphylococcus coagulans, and Coagulase-Negative Staphylococci Cultured from Clinical Canine Skin and Ear Samples in Queensland

Background/Objectives: Infections in dogs caused by methicillin-resistant staphylococci (MRS) present limited treatment options. This study’s objective was to investigate the molecular epidemiology of Staphylococcus spp. cultured exclusively from clinical canine skin and ear samples in Queensland, Australia, using whole-genome sequencing (WGS). Methods: Forty-two Staphylococcus spp. isolated from clinical canine skin and ear samples, from an unknown number of dogs, were sourced from two veterinary diagnostic laboratories between January 2022 and May 2023. These isolates underwent matrix-assisted laser desorption ionisation– time of flight bacterial identification, minimum inhibitory concentration testing using SensititreTM plates and WGS. Phylogenetic trees and core genome multilocus sequence typing (cgMLST) minimum spanning trees (MSTs) were constructed. Results: The isolates included methicillin-resistant and -sensitive S. pseudintermedius (MRSP: 57.1%, 24/42; and MSSP: 19.1%, 8/42), methicillin-resistant and -sensitive S. coagulans (MRSC: 14.3%, 6/42; and MSSC: 2.4%, 1/42) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS: 7.1%, 3/42). Thirty-nine isolates were included after WGS, where all MRS harboured the mecA gene. Eighteen sequence types (STs) were identified, including three novel MRSP and six novel MSSP STs. MRSP ST496-V-VII (23%; 9/39) and MRSP ST749-IV-(IVg) (12.8%; 5/39) were commonly isolated. Phylogenetic analysis of single nucleotide polymorphisms showed that MRSP, MRSC and MSSC were similar to globally isolated staphylococci from canine skin and ear infections. Using cgMLST MSTs, MRSP isolates were not closely related to global strains. Conclusions: Our findings revealed a genotypically diverse geographical distribution and phylogenetic relatedness of staphylococci cultured from clinical canine skin and ear samples across Queensland. This highlights the importance of ongoing surveillance to aid in evidence-based treatment decisions and antimicrobial stewardship.

Engineered Microneedle System Enables the Smart Regulation of Nanodynamic Sterilization and Tissue Regeneration for Wound Management.

The healing of bacterial biofilm-infected wounds is a complex process, and the construction of emerging therapeutic modalities that regulate the microenvironment to magnify therapeutic effects and reduce biotoxicity is still highly challenging. Herein, an engineered microneedle (MN) patch is reported to mediate the efficient delivery of black phosphorus nanosheets (BP NSs) and copper peroxide nanodots (CP NDs) for dual nanodynamic sterilization and methicillin-resistant staphylococcus aureus (MRSA)-infected wound healing. Results demonstrate that the system can eliminate biofilm, reduce cytotoxicity, promote angiogenesis and tissue regeneration by the multiple advantages of chemodynamic therapy (CDT), enhanced photodynamic therapy (PDT), and improved degradation process from BP NSs to phosphate for promoting cell proliferation. Notably, the balance between excellent photodynamic stability and rapid degradability of BP NSs is maintained, and the improved degradation mechanism of BP NSs is vividly elucidated by density functional theory (DFT)-based molecular dynamics (MD) calculations. Furthermore, the transcriptional changes of treated MRSA-infected skin are studied using RNA-seq technology to reveal the potential therapeutic mechanism. As envisaged, the proposed MN patch provides a safe, easy, also highly effective approach to achieve the temporal regulation of sterilization and tissue regeneration for bacterial biofilm-infected wounds.

Complete Genome Assembly of Amycolatopsis bartoniae DSM 45807T Allows the Characterization of a Novel Glycopeptide Biosynthetic Gene Cluster.

Glycopeptide antibiotics (GPAs) are a very successful class of clinically relevant antibacterials, used to treat severe infections caused by Gram-positive pathogens, e.g., multidrug resistant and methicillin-resistant staphylococci. The biosynthesis of GPAs is coded within large biosynthetic gene clusters (BGCs). In recent years, modern DNA sequencing technologies have allowed the identification and characterization of multiple novel GPA BGCs, leading to the discovery of novel compounds. Our previous research anticipated that the genome of Amycolatopsis bartoniae DSM 45807T carries a novel GPA BGC, although the genomic sequence quality available at that time did not allow us to characterize its organization properly. To address this gap, in the current work we aimed to produce a complete genome assembly of A. bartoniae DSM 45807, and to identify and analyze the corresponding GPA BGC. Bioinformatic and microbiological methods were utilized in this research. We de novo sequenced and completely assembled the genome of A. bartoniae DSM 45807, and fully characterized the BGC of interest, named aba. This BGC has an unusual gene organization and it contains four genes for sulfotransferases, which are considered to be rare in GPA BGCs. Our pathway prediction indicated that aba encodes the biosynthesis of a putatively novel GPA, although we were not able to detect any GPA production under different cultivation conditions, implying that aba pathway is inactive. Our results indicate aba as a promising source for new GPA tailoring enzymes.

Appropriate use of vancomycin in a cardiac surgical unit

BackgroundAntibiotic resistance is a rapidly growing problem. Methicillin-resistant staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are major worries, particularly in developing nations where cost-effectiveness is essential. Use of vancomycin must be restricted to prevent resistant to it. Examining the appropriateness rate of vancomycin use in light of the recommendations of the Infectious Disease Society of America (IDSA) in the cardiac surgery ward was the aim of this study.MethodologyThis study was a retrospective analysis of the medical records of patients who received vancomycin over the previous year, from January 2023 to December 2023. The collected patient data included demographics, indications for vancomycin use, culture and sensitivity test results, concurrent antibiotic medications, vancomycin serum levels, and diagnoses. The appropriateness of vancomycin use was classified according to the recommendations of the Infectious Diseases Society of America (IDSA).ResultsA total of 294 patients received vancomycin. The appropriate use of vancomycin was significantly higher than its inappropriate use (p = 0.001). Approximately 41% (n = 120) of patients were administered vancomycin for treatment purposes, while the remainder received it empirically, but not as surgical prophylaxis. Appropriate use of vancomycin was observed in 89.1% (n = 262) of patients. However, there remained a notable rate of inappropriate vancomycin use (n = 32, 10.9%). The most common reason for inappropriate use was the continuation of vancomycin beyond 72 h without further evidence of a Gram-positive infection (n = 21, accounting for 65.6% of all inappropriate use).ConclusionsThe current study demonstrated that 89.1% of vancomycin use was appropriate, while approximately 10% was inappropriate, potentially contributing to vancomycin resistance. The majority of inappropriate use stems from frequent empirical prescribing, which requires further review and monitoring.

Treatment success prediction in patients with methicillin-resistant coagulase-negative staphylococci infections, using vancomycin AUC24/MIC ratio: a multicentre retrospective cohort study.

Although vancomycin is commonly used to treat methicillin-resistant coagulase-negative staphylococci (MRCoNS) infections, there are no clear guidelines for the optimal 24 h AUC24/MIC ratio. This study aimed to determine the target AUC24/MIC ratio associated with vancomycin-treated MRCoNS infection outcomes. This multicentre retrospective cohort study included adult patients who received vancomycin for ≥5 days for bloodstream infections caused by MRCoNS between January 2018 and December 2023. Primary outcome was treatment success, defined as a composite of survival beyond 30 days, clinical success and microbiological eradication. Secondary outcomes included 30-day mortality, clinical success, microbiological eradication and nephrotoxicity. Receiver operating characteristic (ROC) curve analysis was used to identify the AUC24/MIC cut-off for treatment success. Multivariate regression analysis was used to determine the association between AUC24/MIC and outcomes. This study included 147 patients. ROC analysis identified a target AUC24/MIC ≥373 for treatment success. The overall treatment success rate (70.1%) was significantly higher in the above-average AUC24/MIC cut-off group (83.1%) than that in the below AUC24/MIC cut-off group (57.9%). Multivariate analysis confirmed that AUC24/MIC ≥373 was an independent predictor (adjusted OR = 10.227; 95% CI = 3.585-29.171). The 30-day mortality and microbiological eradication rates differed significantly between the below- and above-cut-off groups, whereas nephrotoxicity rates were comparable among the groups. In treating MRCoNS infections, vancomycin AUC24/MIC ratio ≥373 was independently associated with favourable treatment outcomes. However, further prospective studies are required to confirm this target owing to the retrospective nature of this study.

Clinical Outcomes and Complication Rates of Ventriculoperitoneal Shunts in Hydrocephalic Infants with Meningomyelocele: A Ten-Year Review at a Single Institution.

This study aimed to investigate the surgical treatment and management of hydrocephalus in infants with meningomyelocele and compare the single-center experience with the previous studies. This retrospective study included 81 infants (47 females and 34 males) who underwent meningomyelocele closure surgery and subsequent ventriculoperitoneal (VP) shunt surgery for hydrocephalus. Clinical and demographic data were retrospectively collected from hospital records, focusing on variables such as the timing of VP shunt placement relative to MMC closure, postoperative complications, and the need for shunt revisions. Patients were followed for a mean duration of 58.11 months to monitor long-term outcomes and identify factors associated with shunt failures and infections. The mean follow-up period since birth was 58.11 (33.72) months. Shunt problems affected 30% (25/81) of patients with mechanical causes (8/25) and infections (6/25). A proximal mechanical malfunction/dysfunction was seen in 32% (8/25) of the shunts. Shunt infections occurred in 23% (19/81) of infants, and the mean time for shunt infection onset following the VP shunt procedure was 0 (0-39) median (min-max) months. Overall, 8 (9.9%) infants had short-term shunt infections, whereas 11 (13.6%) had long-term shunt infections. The mean length of the intensive care unit stay was 35.75 (25.28) days. Significant difference was seen in the number of shunt reoperations for short- and long-term infections (p < 0.001). All infants had at least one operation before the infection of their shunt system. Male gender was significantly associated with long-term shunt infections (p = 0.021). The study revealed methicillin-resistant coagulase-negative staphylococcus to be the most common isolated organism from infected shunts at 72.7% (6/11). This study demonstrates that hydrocephalic infants with meningomyelocele undergoing VP shunt surgery face notable risks of infection and mechanical complications, with methicillin-resistant coagulase-negative staphylococcus identified as the most common pathogen. The findings emphasize the importance of comprehensive postoperative care and targeted infection management to improve outcomes in this vulnerable population.

Staphylococcus aureus and methicillin-resistant staphylococci and mammaliicocci in the bulk tank milk of dairy cows from a livestock-dense area in northern Italy

Staphylococcus aureus is the main etiologic agent of contagious dairy cow mastitis, while non-aureus staphylococci and mammaliicocci (NASM) are the bacteria most frequently isolated from milk. Beyond their impact on animal health, NASM can harbor antimicrobial resistance (AMR) genes with potential for bidirectional transfer with S. aureus, and methicillin-resistant (MR) staphylococci (MRS) can raise significant One Health concerns. In our study, we evaluated the prevalence and characteristics of MRS in the bulk tank milk (BTM) of 88 dairy farms in the livestock-dense province of Lodi, Lombardy, northern Italy. S. aureus was isolated from 32.95 % of BTM samples, with the Ribosomal Spacer PCR (RS-PCR) genotype B being the most prevalent, identified in 37.93 % of S. aureus positive farms. All isolates carried the ica genes (icaA, icaB, icaC, icaD) indicating the potential to produce biofilm. MRS were isolated in 56.81 % of farms. According to MALDI-TOF MS analysis, the most prevalent MR species included S. epidermidis (MRSE, 35.59 %) followed by S. aureus (MRSA, 18.64 %), M. sciuri (15.25 %), S. saprophyticus (11.86 %), S. borealis (6.78 %), S. haemolyticus (5.08 %), M. fleurettii, (3.39 %), S. cohnii, and S. pettenkoferi (1.70 % each). Most MR isolates carried the mecA gene, while none carried mecC. The staphylococcal cassette chromosome mec (SCCmec) was predominantly type V in MRSA (45.45 %) and type IV in MRSE (61.90 %). Given their relevance to One Health, monitoring AMR in all staphylococci and mammaliicocci isolated from milk is essential for understanding the prevalence, characteristics, and transmission dynamics of MR gene pools within dairy herds.

Presence of Methicillin-Resistant Staphylococci and Carbapenemase-Positive Acinetobacter Isolates on Surfaces in German Dog Daycare Facilities and Correlation with Cleaning Practices.

Many bacteria, including methicillin-resistant staphylococci and opportunistic pathogens such as Acinetobacter (A.) species, in particular members of the A. calcoaceticus-A. baumannii (Acb) complex, are known to survive in environmental settings. This increases the risk of bacterial spreading and transmission to animals and humans, especially in institutions with a high animal population density. This study aimed to identify the presence of multidrug-resistant (MDR) staphylococci and Acinetobacter species in dog daycare facilities (DDFs). The surfaces of 16 DDFs were sampled and information about cleaning practices was obtained. After microbial identification, the detected isolates were investigated by multiplex PCR for antimicrobial resistance genes. In 200 location samples, 38 staphylococci and 109 Acinetobacter spp. isolates were identified. Methicillin-resistant genes were confirmed in 18 staphylococci isolates from four DDFs, including Staphylococcus (S.) equorum, S. saprophyticus, S. cohnii, S. lentus, and S. haemolyticus. Eight A. radioresistens isolates comprising the blaOXA-23 carbapenemase gene and seventeen isolates belonging to the Acb complex were also isolated. This is the first investigation for MDR pathogens in DDFs, a close human-animal interaction environment. Though the role of DDFs in the transmission and spreading of MDR bacteria is not known, the findings should contribute to the public awareness and underscore the necessity of adequate cleaning protocols.

Detection and genetic characterization of multidrug-resistant staphylococci isolated from public areas in an international airport

The environmental realm has been acknowledged as a pivotal arena for the emergence and propagation of antimicrobial resistance. To further explore insight into antimicrobial resistance dynamics beyond clinical and veterinary settings, we embarked on an environmental surveillance initiative targeting the prevalence of antibiotic-resistant bacteria within the bustling confines of an international airport in Japan. Our findings illuminate a high prevalence of methicillin-resistant staphylococci (46.3%) on frequently contacted surfaces in the public domain. Notably, Staphylococcus haemolyticus and S. epidermidis emerged as the preeminent carriers of the mecA gene. Intriguingly, we encountered a virulent strain of livestock-associated MRSA harboring a PVL-positive ST1232 clone, CC398 lineage. Further scrutiny unveiled a repertoire of resistance mechanisms, the methicillin-resistant isolates exhibited two or more resistance genes conferring resistance against different types of antibiotics, including beta-lactams, macrolides, lincosamides, aminoglycosides, chloramphenicol, and fosfomycin. Revealing multidrug-resistant CoNS and a LA-MRSA across various surfaces in urban public areas unearths a looming public health hazard. Thus, implementation of molecular surveillance is imperative, augmenting our capacity for early detection and mitigation of the insidious spread and potential transfer of antibiotic resistance genes and virulence factors amidst urban settings, notably within pivotal nodes such as airports.

Emergence of resistance to last-resort antimicrobials in bacteremia patients: A multicenter analysis of bloodstream pathogens in Korea.

This study retrospectively reviewed the microbiological and clinical characteristics of patients diagnosed with bacteremia. Results from the first positive blood cultures were consecutively collected from July 2022 to June 2023 at a public secondary hospital, a university-affiliated tertiary hospital, and a university-affiliated secondary hospital in the Seoul metropolitan area. Antibiotic spectrum coverage (ASC) scores were calculated on the day the blood culture was performed (B0) and on two days after the blood culture results were reported (R+2). A total of 3,397 isolates were collected from 3,094 patients. Among these, 949 isolates obtained from 893 patients were classified as multidrug-resistant organisms (MDRO), including 170 imipenem-resistant gram-negative bacteria, 714 methicillin-resistant staphylococci, and 65 vancomycin-resistant enterococci. Interestingly, 13 and 42 gram-positive isolates were resistant to linezolid and quinupristin/dalfopristin, respectively. Moreover, 44 and 181 gram-negative isolates were resistant to amikacin and tigecycline, respectively. The proportion of ASC scores corresponding to broad or extremely broad-spectrum coverage was not significantly different between MDRO and non-MDRO groups at B0 (p = 0.0925). However, it increased in the MDRO group at R+2 (p <0.001). This study found that resistance to last-resort antimicrobials is emerging. Therefore, developing and incorporating molecular diagnostics using a wide range of resistance targets may facilitate rapid, tailored antimicrobial treatments.

Increased incidence of methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis in the skin and nasal carriage among healthcare workers and inanimate hospital surfaces after the COVID-19 pandemic.

Healthcare workers in hospitals are exposed to infectious diseases that occur in the hospital making them a source of infection for the patients. It is interfaced as cross-contamination agents for MRSA and MR-CoNS, and preventive measures need to be adapted accordingly. The study aimed to assess Methicillin-Resistant Staphylococcus (MRS) on the skin and nasal cavities of healthcare workers (HCWs) and identifying isolates to the species level. Swab samples were cultured on mannitol salt agar (MSA) to obtain MRS and determine their ability to produce coagulase. Their susceptibility to antibiotics were determined by agar screening and disk diffusion methods and further identification was done at the species level. The highest percentage of methicillin resistant coagulase positive Staphylococci (MRCoPS) was reported among skins of male HCWs, (71.4%) were identified as MRSA. The highest levels of methicillin resistant coagulase negative Staphylococci (MRCoNS) were mainly detected in both nasal cavities, (75%) were identified as MRSE. MRSA was reported from doctors (p-value 0.033), whereas the highest incidence of MRSE was obtained from the nurses (p-value 0.048). This study highlighted that incidence of MRSA was mainly detected in doctors and MRCoNS in both nasal cavities. The highest percentage of MRCoNS was recovered from the patients' room followed by the reception table. Moreover, vancomycin is suggested to be highly effective in managing and controlling S. aureus, MRSA- and MRSE related infections.

Evaluation of a nucleic acid amplification system, GENECUBE, for rapid detection of staphylococcal nuc and mecA in blood culture samples

ObjectiveThis study determined whether the GENECUBE rapid nucleic acid amplification test could directly detect nuc and mecA genes in clinical blood culture samples of Staphylococcus and various other pathogens. MethodsBetween September 2020 and December 2021, 537 blood culture samples from 192 patients with suspected bacteremia were tested using conventional assays (MicroScan WalkAway96 or VITEK 2 systems) and GENECUBE nuc and mecA assays. Isolates from samples with discrepant results between the conventional and GENECUBE assays were further evaluated using MALDI-TOF mass spectrometry, disk diffusion testing using cefoxitin, broth microdilution testing using oxacillin, and sequencing for mecA. Bacterial solutions containing a mixture of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) were prepared to evaluate the limit of detection (LOD) of mecA. ResultsUsing conventional assays as the reference, the sensitivity, specificity, and positive and negative predictive values (95 % confidence interval) of GENECUBE were 100 % (96.8–100 %), 100 % (99.1–100 %), 100 % (96.8–100 %), and 100 % (99.1–100 %), respectively, for nuc detection and 100 % (96.1–100 %), 98.9 % (97.4–99.6 %), 94.9 % (88.5–98.3 %), and 100 % (99.2–100 %), respectively, for mecA detection. Sequencing analysis of five samples identified as methicillin-sensitive staphylococci using conventional assays and methicillin-resistant staphylococci using GENECUBE revealed the presence of methicillin-resistant isolates in all samples. The estimated LOD of mecA was 104 colony-forming units (CFU)/mL of MRSE with GENECUBE, compared with 105 CFU/mL with conventional assays. ConclusionThe GENECUBE assay accurately detected mecA in positive blood culture samples and had higher sensitivity than conventional assays.

Impact of Methicillin-Resistant Staphylococcus aureus Nasal Polymerase Chain Reaction Screening Tests on Duration of Vancomycin Therapy for Skin and Soft Tissue Infections.

Background: Recent literature demonstrated a 24-hour reduction in vancomycin duration of therapy (DOT) for skin and soft tissue infections (SSTIs) with a negative methicillin-resistant staphylococcus aureus (MRSA) nasal screening versus a positive nasal screening. Objective of this study was to investigate vancomycin DOT in patients with SSTIs who received MRSA nasal polymerase chain reaction (PCR) screening versus those who did not receive MRSA nasal PCR screening. Methods: A retrospective, multi-center, cohort study was completed in admitted adult patients on vancomycin for SSTI from 01/01/2020 to 09/30/2022. Hospital policy permits any clinician to order a MRSA nasal PCR screening test for various indications, including SSTIs, pneumonia and sepsis. Results: One-hundred-fifty-one patients were included, of which 71 had MRSA nasal PCR screening tests obtained, and 80 did not. The median vancomycin DOT in patients with MRSA nasal PCR screening tests was 19.9 versus 36.7 hours (P = .014) in patients without screening tests. Conclusion: Patients with SSTIs who receive MRSA nasal PCR screening tests have a shortened vancomycin DOT. These results contribute to current data in support of the efficacy and clinical utility of obtaining MRSA nasal PCR screening tests for SSTIs.

Clinical Evaluation of Blood Culture Identification Gram-Positive Panel on Methicillin Resistant Gene Testing in a Large Metropolitan Teaching Hospital

Abstract Introduction The ePlex blood culture identification (BCID) gram-positive panel is a PCR-based approach used for the detection of common pathogens associated with bloodstream infections and corresponding antibiotic-resistance genes. One of the genes, mecA, is associated with methicillin, penicillin, and other penicillin-like-antibiotic-resistant gram-positive bacteria (GPB). It is unclear whether the BCID panel has predictive utility and accuracy in treating hospital infections due to GPB. This retrospective study attempts to determine the consistency and accuracy of BCID gene testing compared to more traditional susceptibility methods at a large public hospital. Method A search query was performed for all BCID results at one teaching hospital in a large metropolitan area for one year (2022). The query included demographic information, BCID results, culture results, and combined susceptibility data. The results were filtered to include only cases in which the mecA gene was detected. The filtered results were then analyzed to determine if the susceptibility results from the susceptibility platform (VITEK) were consistent with the expected susceptibility of the target gene, specifically for oxacillin and vancomycin. The susceptibility cutoff was set as &amp;gt;0.5 mcg/mL and &amp;lt;1 mcg/mL respectively, the standard threshold used at the institution. Results A total of 1211 culture results were obtained, of which the mecA gene was identified by BCID in 321 cases, along with the following GPB: Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus sp. (not aureus). The corresponding cultures grew the following isolates: S. aureus, S. epidermidis, S. hominis, and S. haemolyticus. Of the 321 BCID results, 75 were identified as S. aureus. The isolates grew methicillin-resistant Staph aureus (MRSA) (69/75) 92%, while the typical S. aureus grew (6/75) in 8% of the isolates. In these cases, we compared susceptibility testing for both isolates as either sensitive or resistant, with a MIC of &amp;gt;0.5 mcg/mL for oxacillin to be designated as resistant, and &amp;lt;1 mcg/mL to be designated as sensitive to vancomycin. Of the 75 specimens, the concordance rate was 97% (73/75) for oxacillin and 100% (75/75) for vancomycin. The average receipt to verification turnaround time (TAT) was 36 hours for BCID results and 121 hours (about 5 days) for culture sensitivity results. Conclusion The results show that oxacillin resistance can be predicted by detecting S. aureus and the mecA gene using the BCID panel. However, the mecA gene can be identified in other GPB such as S. epidermidis, in which it should not be used to infer oxacillin or vancomycin susceptibilities. In the case of mecA and S. aureus detection by BCID, treating the patient as a MRSA infection may be appropriate before the susceptibilities have been performed. This approach can reduce the turnaround time for antimicrobial resistance reporting and improve antimicrobial stewardship efforts.

A single-center analysis of pathogenic bacteria distribution and drug resistance in bacterial bloodstream infections among patients with hematological diseases

Objective: To analyze the distribution and drug resistance of pathogens of bacterial bloodstream infection in patients with hematological diseases in the Department of Hematology of Tianjin Medical University General Hospital, and to provide etiological data for clinical empirical anti-infection treatment. Methods: A retrospective analysis was conducted on the general clinical information, pathogenic bacteria and drug susceptibility test results of patients with hematological diseases diagnosed with bacterial bloodstream infection by menstrual blood culture in our center from January 2016 to December 2022. Results: Patients included 498 inpatients, with a total of 639 bacterial strains. Among the patients, 86.9% patients had malignancies, and 76.7% had agranulocytosis. Symptoms of concurrent infections, including those of the respiratory tract, oral mucosa, skin and soft tissues, and abdominal sources were observed in 68.3% patients. Gram-negative bacteria (G(-)) accounted for 79.0% of the isolated bacteria, and gram-positive bacteria (G(+)) accounted for 21.0%. The top five isolated pathogens were Klebsiella pneumoniae (22.5%), Escherichia coli (20.8%), Pseudomonas aeruginosa (15.0%), Enterococcus faecium (5.5%), and Stenotrophomonas maltophilum (5.0%). Escherichia coli exhibited a decreasing trend of resistance to quinolones, cephalosporins, and carbapenems. Klebsiella pneumoniae exhibited increasing rates of resistance to quinolones and cephalosporins between 2016 and 2018, but the rated decreased after 2019. The resistance rate to carbapenems exhibited by Pseudomonas aeruginosa was approximately 20%. Carbapenem-resistant strains of Pseudomonas aeruginosa strains were first detected in 2017, with a peak resistance rate of 35.7%, detected in 2019. A 60.0% resistance rate to methicillin was observed in methicillin-resistant coagulase-negative staphylococci (MRCNS), and one case of linezolid-resistant MRCNS was detected. Conclusions: Pathogenic bacteria of bacterial bloodstream infections were widely distributed in our center, and precautions are warranted against carbapenem resistant P. aeruginosa and Klebsiella pneumoniae.

Microflora of Secretions in a Surgical Hospital of Orthopedics and Traumatology Profile for 2021-2023 (SI “ITO NAMS of Ukraine”)

Summary. Healthcare-associated infections (HAIs), namely, surgical site infections, early postoperative and subsequent in-hospital infections, are the most common undesirable phenomenon in the world. According to statistics, at least one case of HAIs is diagnosed in every 100 hospitalized patients in hospitals of 7 developed and 15 other countries of the world at any given time. The occurrence of such complications during the treatment of a patient in a hospital leads to the need of additional diagnostic tests, additional courses of antibiotics, and unplanned surgical intervention. Worsening of the prognosis of treatment may occur due to the formation of the so-called resistant microflora in such patients, with a real probability of spreading the infection in the hospital. Prevention of HAIs in practice occurs through planned infection control in operating rooms and procedure rooms in clinical departments and qualified timely diagnostic work of certified microbiological laboratories in hospitals. Objective. The objective of the study was to determine the spectrum of microflora of secretions for three years (2021-2023) in orthopedic and trauma patients due to changes in modern injuries received more often because of military aggression and to propose the identified differences as criteria for prescribing antibacterial drugs in complex inpatient treatment. The work shows that over the past three years (2021-2023), the ratio of gram-positive and gram-negative microorganisms in the study material almost did not change and averaged 1.65. The peculiarity of the analyzed period was an increase in the number of methicillin-resistant staphylococci by 1.3 times. The spectrum of gram-negative clinical strains has changed, namely, the number of Kl.pneumoniae clinical strains with a high level of polyresistance has increased by 2.5 times. The obtained data made it possible to identify the spectrum of microflora of secretions in orthopedic and trauma patients with modern infectious complications, which prompts us to make changes in the standards of antibacterial treatment protocols, and to plan the needs for certain antibiotics in hospitals with personalization of their prescription to improve the effectiveness of treatment and reduce the risk of development of antimicrobial resistance.

Performance of the GeneXpert® MRSA/SA SSTI Test in Periprosthetic Joint Infections: Rate of failure, Outcomes and Risk Factors

BackgroundThe GeneXpert® MRSA/SA SSTI test allows early detection of methicillin-resistant staphylococci in intraoperative samples of prosthetic joint infections (PJI) in order to stop early broad-spectrum antibiotics. Questions/Purpose(1) What is the rate of false-negative GeneXpert® MRSA/SA SSTI test results? (2) Does a false-negative GeneXpert® MRSA/SA SSTI test result increase the risk of treatment failure for the patient with a PJI? (3) What are the risk factors of a false-negative result? MethodA retrospective study was carried out to compare all GeneXpert® assays to conventional cultures in prosthetic joint infections from April 1st, 2012 to October 1st, 2016. False-negative (FN) results (absence of methicillin-resistant staphylococci (MRS) with GeneXpert® test, but presence in the culture) were identified. We compared the rate of treatment failure between FN results and other test results and we established the risk factors of having a FN result. ResultsAmong the 612 GeneXpert® results, the rate of FN results was 3.6 % (22/612). We found a significant increase in treatment failures for prosthetic joint infection with a FN result with 14 treatment failures (14/22) compared to 198 treatment failures (198/590) in the other test results (OR, 2.1; 95 % CI, 1.3-3.4, p = 0.0019). Not considering suppressive antibiotics as a treatment failure, we found no significant difference in the rate of treatment failures between the false-negative tests and the other tests (OR, 1.36; 95 % CI, 0.66-2.81, p = 0.41). Tobacco use (OR, 3.8; 95 % CI, 1.4-10.3, p = 0.004), ASA classification (OR, 2,4; 95 % CI, 0.9-6.9, p = 0.064), history of infection in the joint (OR, 3.2; 95 % CI, 1.2-9.6, p = 0.007), chronic infections (OR, 3.2; 95 % CI, 0.8-17.5, p = 0.01) and polymicrobial infections (OR, 3.2; 95 % CI, 1.1-9.2, p < 0.0001) were risk factors for a FN result. ConclusionGeneXpert® tests in prosthetic joint infections showed a low rate of FN results. An increased risk of treatment failures was observed in FN results only when long-term use of suppressive antibiotics was considered as treatment failure. Level of evidenceIII; Diagnostic retrospective case control study.

Genetic identification of methicillin resistant Staphylococcus aureus (MRSA) isolated from diabetic foot ulcers and evaluating the inhibition activity of reuterin against this bacteria.

To genetically diagnose the isolates of methicillin-resistant staphylococcus aureus taken from patients with severe diabetic foot infections, and to test the inhibitory effect of reuterin on the growth of these bacteria. The experimental study was conducted from June to November 2021 at the Diabetes Unit of Al-Faihaa General Hospital, Basrah, Iraq, and comprised 62 foot ulcer swabs from the necrotic lesions of patients with type 2 diabetes. The swabs were cultivated first in brain heart infusion broth media, and then streaked on Mannitol salt agar and staphylococcus chromogeneic agar media for phenotypic and genetic analysis. The genetic identification of bacteria was confirmed by deoxyribonucleic acid extraction, and methicillin-resistant staphylococcus aureus was confirmed by the presence of plasmid mecA gene. The inhibition activity of reuterin towards methicillin-resistant staphylococcus aureus was determined using the minimum inhibitory concentration test. All data was analyzed with SPSS version 23. A total of 62 swabs were taken from the necrotic lesions of type 2 diabetes mellitus (T2DM) patients with diabetic foot ulcers. Of the total isolates, 9(14.5%) gave mauve to purple colour on staphylococcus chromogeneic agar, which was then genetically confirmed as methicillin-resistant staphylococcus aureus. The minimum inhibitory concentration value of these bacteria was 10μl/ml at 16mm inhibition zone diameter. There was no cytotoxicity of reuterin to human red blood cells. Reuterin was found to be a natural antimicrobial substance suitable for use to disinfect diabetic foot wounds from bacterial contamination and infection, especially those caused by methicillin-resistant staphylococcus aureus.

ANTIBIOTICS RESISTANCE PATTERNS IN GRAM POSITIVE UROPATHOGENS IN CHILDREN

Background:Children and infants are commonly infected with UTIs due to several anatomical reasons and hygiene measures. This study was conducted to see antibiotic-resistant patterns in Gram Positive Uropathogens in children in Children's Hospital, Lahore. The most common organisms causing UTI in children are gram-negative pathogens but some gram-positive pathogens.Materials &amp;Methods:Urine samples obtained from 200 children taken with non-probability,convenient method presenting with UTI were cultured on CLED agar and then drug sensitivitytesting of isolated gram positive bacteria (n=25) was performed using Disk diffusion (Kirby Bauer)method on Muller Hinton agar plates as per standard laboratory guidelines.A descriptive study(cross-sectional)was conducted to assess sensitivityagainst Ampicillin, Cotrimoxazole,amoxicillin, cefotaxime, Ceftriaxone, tobramycin, amikacin, Sulbactam, Nitrofurantoin, andPolymixin B.Results:The mean age of children in this study was 2.4 years from 0 to 5 years. Among Gram positive uropathogens Staphylococcus aureus (65%) was the commonest organism isolated. Enterococci were isolated in 25% of cases. Coagulase-negative staphylococci were 10%. Gram positive cocci included Methicillin Sensitive Staphylococcus Aureus (MSSA) (50%) and Methicillin Resistant Staphylococci (MRSA) (50%). The highest resistance was noted against Ampicillin (68%). The lowest resistance was noted against tobramycin (24%).Conclusion:Emerging antibiotic resistance has rendered many first-line drugs ineffective against UTI-causing organisms and treatment regimens need to be revised.