Methicillin-resistant Coagulase-negative Staphylococci Research Articles

Characterization of linezolid- and methicillin-resistant coagulase-negative staphylococci in a tertiary hospital in China

BackgroundRecently, linezolid-resistant staphylococci have become an emerging problem worldwide. Understanding the mechanisms of resistance, molecular epidemiology and transmission of linezolid-resistant CoNS in hospitals is very important.MethodsThe antimicrobial susceptibilities of all isolates were determined by the microdilution method. The resistance mechanisms and molecular characteristics of the strains were determined using whole-genome sequencing and PCR.ResultsAll the strains were resistant to oxacillin and carried the mecA gene; 13 patients (36.1%) had prior linezolid exposure. Most S. epidermidis and S. hominis isolates were ST22 and ST1, respectively. MLST typing and evolutionary analysis indicated most linezolid-resistant CoNS strains were genetically related. In this study, we revealed that distinct CoNS strains have different mechanisms of linezolid resistance. Among ST22-type S. epidermidis, acquisition of the T2504A and C2534T mutations in the V domain of the 23 S rRNA gene, as well as mutations in the ribosomal proteins L3 (L101V, G152D, and D159Y) and L4 (N158S), were linked to the development of linezolid resistance. In S. cohnii isolates, cfr, S158Y and D159Y mutations in the ribosomal protein L3 were detected. Additionally, emergence of the G2576T mutation and the cfr gene were major causes of linezolid resistance in S. hominis isolates. The cfr gene, G2576T and C2104T mutations, M156T change in L3 protein, and I188S change in L4 protein were found in S. capitis isolates.ConclusionThe emergence of linezolid-resistant CoNS in the environment is concerning because it involves clonal dissemination and frequently coexists with various drug resistance mechanisms.

A 10-year Retrospective Review of Patient-to-Patient Transmitted Pathogens in Culture-Positive Burn Wounds at a Tertiary Burn Center

Introduction: Burn wound infection can progress to sepsis and is a significant source of morbidity and mortality. Prevalence of multidrug-resistant organisms are high in burn patients; these organisms can be transmitted between patients leading to poor outcomes. Objectives: To characterize patient-to-patient transmission of pathogens causing burn wound colonization at a single tertiary hospital burn center in Hamilton, Canada from 2011 to 2020. Methods: Retrospective chart review of patients admitted to the burn trauma unit at Hamilton General Hospital between 2011 and 2020. Antibiotic susceptibility panels of pathogens cultured from burn patients’ wound swab/tissue cultures were compared against pathogens cultured from other burn/nonburn patients with overlapping admission dates. Pathogens were categorized into likely, possible, or unlikely transmission, or normal skin flora on a case-by-case basis. Results: There were 173 burn patients with positive wound culture and 613 nonburn patients included in the study. Included burn patients had median age 52 years, mostly male (73%) with flame injury (65%), and median total body surface area 18%. There were 18 patients (10%) with likely transmission and 54 patients (31%) with possible transmission. Most frequently implicated pathogens for likely patient-to-patient transmission were methicillin-resistant Staphylococcus aureus (MRSA) (7 patients) and methicillin-resistant coagulase-negative Staphylococci (4 patients). Both burn and nonburn patients were implicated. Conclusion: The burden of patient-to-patient transmission in culture-positive burn wounds was estimated to be between 10% and 41%. Greater care should be taken to avoid patient-to-patient transmission of pathogens to minimize burn infection morbidity and mortality. Prospective studies should be conducted with genomic sequencing and correlation with clinical outcomes.

The Home Environment Is a Reservoir for Methicillin-Resistant Coagulase-Negative Staphylococci and Mammaliicocci.

Coagulase-negative staphylococci (CoNS) and mammaliicocci are opportunistic human and animal pathogens, often resistant to multiple antimicrobials, including methicillin. Methicillin-resistant CoNS (MRCoNS) have traditionally been linked to hospitals and healthcare facilities, where they are significant contributors to nosocomial infections. However, screenings of non-hospital environments have linked MRCoNS and methicillin-resistant mammaliicocci (MRM) to other ecological niches. The aim of this study was to explore the home environment as a reservoir for MRCoNS and MRM. A total of 33 households, including households with a dog with a methicillin-resistant staphylococcal infection, households with healthy dogs or cats and households without pets, were screened for MRCoNS and MRM by sampling one human, one pet (if present) and the environment. Samples were analyzed by a selective culture-based method, and bacterial species were identified by MALDI-TOF MS and tested for antibiotic susceptibility by the agar disk diffusion method. Following whole-genome sequencing, a large diversity of SCCmec elements and sequence types was revealed, which did not indicate any clonal dissemination of specific strains. Virulome and mobilome analyses indicated a high degree of species specificity. Altogether, this study documents that the home environment is a reservoir for a variety of MRCoNS and MRM regardless of the type of household.

Microorganism diversity and contamination risk in mosque rosaries and carpets.

Inevitably, the floors of mosques are contaminated with microorganisms, and the risk of pathogen transmission is probably high between the many visitors, but the issue has been infrequently studied. Investigate microorganism variety and risk of contamination on commonly used carpets and rosaries (prayer beads). Cross-sectional. Mosques. This study was carried out in three different cities of Turkey in 2023, focusing on mosques located around hospitals. Forty mosques were included in the study and from each mosque 10 samples were collected from various parts of carpets and rosaries. The number of positive culture isolates were identified. Diversity and distribution of microorganisms isolated from mosque carpets and rosaries; methicillin-resistance rates in Staphylococci. 400 samples. Growth was observed in 368 (92%) of 400 samples examined. The microorganisms isolated in the highest number were methicillin-susceptible coagulase negative Staphylococci (MSCoNS) (59.8%), Microcooccus (41%) and diphtheroids (31.3%). The rates of total growth (P=.001), including diphtheroids (P=.018), methicillin-resistant coagulase negative Staphylococci (P=.001), Bacillus spp. (P=.036) and Aspergillus spp. (P=.002) rates were significantly higher in the rosary samples than carpet samples. At mosques in Tokat, a province center, 4 samples were positive for Acinetobacter baumannii, two samples were positive for Pseudomonas aeruginosa and one sample for methicillin-resistant Staphylococcus aureus (MRSA), and these were isolated from rosaries. 0.3% of Staphylococcus isolates were MRSA. As there is a high risk of contamination of carpets and prayer beads on the mosque floor with human flora, the use of appropriate hygiene practices is necessary. We also found some emerging bacteria in addition to the normal human flora. Our study was conducted in three provinces. Further studies might cover a wider geography.

Evaluation of two commercial broth microdilution systems for dalbavancin susceptibility testing of methicillin-resistant Staphylococcus aureus and other resistant Gram-positive cocci

ObjectivesThis study aims to evaluate two commercial broth microdilution (BMD) systems, E1-185-100 (Merlin) and FDANDPF (ThermoFisher), for dalbavancin susceptibility testing in comparison with reference BMD assay. MethodsStudy collection was composed of 200 non-replicate multidrug-resistant Gram-positive cocci of clinical origin, including 180 methicillin-resistant Staphylococcus aureus, 10 vancomycin-resistant enterococci, seven linezolid-resistant Staphylococcus epidermidis, and three methicillin-resistant coagulase-negative staphylococci. S. aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 reference strains were also included as controls. Testing was performed according to the ISO 20776-1 standard, starting from the same bacterial inoculum, and results were compared according to the ISO 20776-2 standard. ResultsReference BMD showed that 92.6% (187/202) of the strains were susceptible to dalbavancin, whereas few staphylococci and all VanA-producing enterococci showed a resistant phenotype. In comparison with the reference method, Category Agreement and Essential Agreement were 98% (198/202; 95% CI, 95.4–99.3%) and 98% (198/202; 95% CI, 95.4–99.3%) for both Merlin and ThermoFisher panels. A few false susceptibilities were observed, for both commercial systems, with dalbavancin-resistant staphylococci. BIAS values of 11% and 3% were calculated for the Merlin and ThermoFisher systems, respectively. DiscussionThis study, reporting the first evaluation of the two commercially available BMD assays for dalbavancin susceptibility testing, revealed an overall good correlation with reference BMD, although with some underestimation tendency of MIC values by both commercial systems. Further studies involving a higher number of resistant isolates will be necessary to better evaluate this issue.

Differences in microorganisms causing infection after cranial and spinal surgeries.

The primary aim of this retrospective study was to assess differences in the pathogens causing surgical site infections (SSIs) following craniectomies/craniotomies and open spinal surgery. The secondary aim was to assess differences in rates of SSI among these operative procedures. ANOVA tests with Bonferroni correction and incidence risk ratios (RRs) were used to identify differences in pathogens by surgical site and procedure using retrospective, de-identified records of 19,993 postneurosurgical patients treated between 2007 and 2020. The overall infection rates for craniotomy/craniectomy, laminectomy, and fusion were 2.1%, 1.1%, and 1.5%, respectively, and overall infection rates for cervical, thoracic, and lumbar spine surgery were 0.3%, 1.6%, and 1.9%, respectively. Craniotomy/craniectomy was more likely to result in an SSI than spine surgery (RR 1.8, 95% CI 1.4-2.2, p < 0.0001). Cutibacterium acnes (RR 24.2, 95% CI 7.3-80.0, p < 0.0001); coagulase-negative staphylococci (CoNS) (methicillin-susceptible CoNS: RR 2.9, 95% CI 1.6-5.4, p = 0.0006; methicillin-resistant CoNS: RR 5.6, 95% CI 1.4-22.3, p = 0.02); Klebsiella aerogenes (RR 6.5, 95% CI 1.7-25.1, p = 0.0003); Serratia marcescens (RR 2.4, 95% CI 1.1-7.1, p = 0.01); Enterobacter cloacae (RR 3.1, 95% CI 1.2-8.1, p = 0.02); and Candida albicans (RR 3.9, 95% CI 1.2-12.3, p = 0.02) were more commonly associated with craniotomy/craniectomy cases than fusion or laminectomy SSIs. Pseudomonas aeruginosa was more commonly associated with fusion SSIs than craniotomy SSIs (RR 4.4, 95% CI 1.3-14.8, p = 0.02), whereas Escherichia coli was nonsignificantly associated with fusion SSIs compared to craniotomy SSIs (RR 4.1, 95% CI 0.9-18.1, p = 0.06). Infections with E. coli and P. aeruginosa occurred primarily in the lumbar spine (p = 0.0003 and p = 0.0001, respectively). SSIs due to typical gastrointestinal or genitourinary gram-negative bacteria occur most commonly following lumbar surgery, particularly fusion, and are likely to be due to contamination of the surgical bed with microbial flora in the perianal area and genitourinary tract. Cutibacterium acnes in the skin flora of the head and neck increases risk of infection due to this microbe following surgical interventions in these body sites. The types of gram-negative bacteria associated with craniotomy/craniectomy SSIs suggest potential environmental sources of these pathogens. Based on the authors' findings, neurosurgeons should consider using a two-step skin preparation with benzoyl peroxide, in addition to a standard antiseptic such as alcoholic chlorhexidine for cranial, cervical, and upper thoracic surgeries. Additionally, broader gram-negative bacterial coverage, such as use of a third-generation cephalosporin, should be considered for lumbar/lumbosacral fusion surgical antibiotic prophylaxis.

New Frontier on Antimicrobial Therapy: Long-Acting Lipoglycopeptides.

Long-acting lipoglycopeptides (LGPs), such as dalbavancin and oritavancin, are semisynthetic antibiotics known for their strong effectiveness against a wide array of Gram-positive bacteria. This includes Staphylococcus aureus, both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) strains, coagulase-negative Staphylococci (CoNS), streptococci, and vancomycin-sensitive Enterococcus faecalis. A literature search was conducted on PubMed and on ClinicalTrials.gov to identify articles published until July 2023 investigating the use of oritavancin and dalbavancin in clinical practice. The review included case reports, case series, observational studies, and clinical studies. Although more consistent data are needed, LGPs seem to be a good alternative that may provide a quicker hospital discharge and reduce long-term intravenous access and therapy. This is attributed to their unique pharmacologic and pharmacokinetic characteristics. More quality data (i.e., number of patients treated with clinical success) are needed before clinicians may use these therapies more widely.

SCCmec transformation requires living donor cells in mixed biofilms

Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that has emerged through the horizontal acquisition of the staphylococcal cassette chromosome mec (SCCmec). Previously, we showed that SCCmec from heat-killed donors can be transferred via natural transformation in biofilms at frequencies of 10−8-10−7. Here, we show an improved transformation assay of SCCmec with frequencies up to 10−2 using co-cultured biofilms with living donor cells. The Ccr-attB system played an important role in SCCmec transfer, and the deletion of ccrAB recombinase genes reduced the frequency ∼30-fold. SCCmec could be transferred from either MRSA or methicillin-resistant coagulase-negative staphylococci to some methicillin-sensitive S. aureus recipients. In addition, the transformation of other plasmid or chromosomal genes is enhanced by using living donor cells. This study emphasizes the role of natural transformation as an evolutionary ability of S. aureus and in MRSA emergence.

Two-Stage Treatment Protocol of Fungal Periprosthetic Hip and Knee Joint Infections: the Clinical Experience from a Single Center Experience.

To evaluate the clinical results and safety of fungal periprosthetic joint Infections (fPJIs) using two-stage treatment protocol. 8 patients with fPJIs (3 hips and 5 knees) using two-stage revision were reviewed retrospectively and followed up at least 2 years. The preoperative demographic data, two-stage treatment protocol, results of microbiology and histologic workup and postoperative follow-up results (reimplantation success rate and infection free time) were recorded. 7 patients got successful reimplantation, with a 75% reimplantation success rate. Two patients got knee arthrodesis eventually. All patients were infection free with a median follow-up of 4.0 ± 2.0 years (range, 2-7 years). Of them, Candida species were found in 7 patients, while non-Candida specimen was only isolated in 1 patient with Aspergillus. Only 2 patients had coexisting bacterial infection (Methicillin-resistant coagulase-negative Staphylococci and Proteus mirabilis respectively). The average interval between the initial surgery and diagnosis of fPJIs was 21.50±34.79 months (range, 4-104 months). The mean time of spacer implantation was 7.75±2.77 months (range, 6-14 months). None serious complication or above knee amputation was found. fPJIs are very rare and considerable challenge after total hip or knee arthroplasty. The goal of therapy is to eradicate local infection and maintain function. Candida species were the most common pathogen. The duration between spacer placement and staged reimplantation was highly variable, and generally dependent upon the results of joint aspirates and infl ammatory markers. The current study shows that the two-stage treatment protocol is recommended for fungal periprosthetic hip and knee joint infections. The two-stage treatment protocol is recommended for fungal periprosthetic hip and knee joint infections. The safety and effi cacy of biantibiotical impregnated (antifungal + antibiotics) cement spacer is confi rmed. Further evidence-based work is needed to determine the optimal drug dose and reimplantation time. two-stage treatment protocol, fungal periprosthetic infections, hip spacer, knee spacer.

Antibiotic Resistance to Molecules Commonly Prescribed for the Treatment of Antibiotic-Resistant Gram-Positive Pathogens: What Is Relevant for the Clinician?

Antibiotic resistance in Gram-positive pathogens is a relevant concern, particularly in the hospital setting. Several antibiotics are now available to treat these drug-resistant pathogens, such as daptomycin, dalbavancin, linezolid, tedizolid, ceftaroline, ceftobiprole, and fosfomycin. However, antibiotic resistance can also affect these newer molecules. Overall, this is not a frequent phenomenon, but it is a growing concern in some settings and can compromise the effectiveness of these molecules, leaving few therapeutic options. We reviewed the available evidence about the epidemiology of antibiotic resistance to these antibiotics and the main molecular mechanisms of resistance, particularly methicillin-resistant Sthaphylococcus aureus, methicillin-resistant coagulase-negative staphylococci, vancomycin-resistant Enterococcus faecium, and penicillin-resistant Streptococcus pneumoniae. We discussed the interpretation of susceptibility tests when minimum inhibitory concentrations are not available. We focused on the risk of the emergence of resistance during treatment, particularly for daptomycin and fosfomycin, and we discussed the strategies that can be implemented to reduce this phenomenon, which can lead to clinical failure despite appropriate antibiotic treatment. The judicious use of antibiotics, epidemiological surveillance, and infection control measures is essential to preserving the efficacy of these drugs.

Bacteriological Profile and Antibiogram of Aerobic Blood Culture Isolates among Suspected Blood Stream Infections: A Cross-sectional Study

Introduction: Bloodstream Infections (BSIs) are important causes of morbidity and mortality worldwide. Blood culture is the most important diagnostic tool for BSI. The epidemiology and outcome of BSI are constantly changing due to increasing antimicrobial resistance, changing patterns of antibiotic drug usage, and the increased use of transient or permanent medical devices. Thus, regular monitoring of the bacterial aetiology of BSI and their antibiograms is necessary. Aim: To determine the bacteriological profile and antibiotic susceptibility patterns among suspected BSI patients. Materials and Methods: A hospital-based cross-sectional study was carried out in the Department of Microbiology, Jawaharlal Nehru Institute of Medical Sciences (JNIMS), Imphal, Manipur, India, from September 2018 to August 2020. A total of 481 suspected BSI patients were included in the study. The blood culture samples were collected under aseptic conditions and cultured for seven days. The isolates were identified using conventional biochemical tests, and the antibiotic susceptibility pattern was determined by the Kirby-Bauer disk diffusion method and the epsilometer test (E-test). Methicillin resistance among the staphylococcal isolates was detected using the cefoxitin disk diffusion method. Data analysis was performed using EpiInfoTM version 7.0, and the Chi-square test was used as a statistical test. Results: A total of 150 (31.2%) blood samples were culture positive out of the 481 samples processed from suspected BSI patients. The predominant isolates were gram-positive, accounting for 113/150 (75.3%), while gram-negatives accounted for 37/150 (24.7%). Staphylococcus aureus, Pseudomonas aeruginosa, and Coagulase Negative Staphylococci (CoNS) were the primary pathogens isolated. Methicillin resistance was detected in 59 (54.6%) of the staphylococcal isolates {52 (54.7%) were Methicillin Resistant S. aureus (MRSA), and out of the 13 CoNS isolates, 7 (53.9%) were Methicillin Resistant CoNS (MRCoNS)}. The most susceptible drugs for gram-positives were vancomycin and linezolid, while aminoglycosides and imipenem were the most susceptible drugs for gram-negatives. Conclusion: The study highlighted the prevalence and pattern of aerobic bacterial isolates in BSI cases at JNIMS Hospital, as well as, the antibiotic susceptibility patterns of the isolates. Regular epidemiological studies of BSIs, regarding the pathogens and their antibiotic susceptibility patterns, are necessary to guide clinicians in choosing appropriate empirical therapy and to update the hospital antibiotic policy from time to time. This promotes rational antibiotic use and reduces resistance among bacteria.

Prevalence and Antibiotic Resistance of Bacteria Isolated from Cerebrospinal Fluid of Neurosurgical Patients in Malang, Indonesia

Background: Central nervous system infections are a critical concern in neurosurgical practice, often leading to severe complications and prolonged hospital stays. Understanding the prevalence and antibiotic resistance patterns of the bacteria causing these infections is essential for effective patient management. This study aims to investigate the prevalence and antibiotic resistance profiles of bacteria isolated from cerebrospinal fluid in neurosurgical patients in Malang, Indonesia. Materials and Methods: A retrospective analysis was conducted to investigate the positive cerebrospinal fluid (CSF) cultures in patients who underwent craniotomy within the period of January 2019 to December 2021. The gathered data encompassed the identification of etiological agents and the determination of their respective antimicrobial susceptibilities. Data analysis was performed on a total of 33 individuals, with 67 isolates out of 239 patients and 515 CSF culture samples. Results: The preponderant microorganism identified in the sample was coagulase-negative Staphylococci, with a majority exhibiting methicillin resistance, commonly referred to as methicillin-resistant coagulase-negative Staphylococci (MRCoNS). All specimens exhibited susceptibility to both vancomycin and tigecycline. Klebsiella pneumoniae, a Gram-negative bacterium, was identified as the predominant etiological agent and exhibited resistance to a substantial proportion of the antimicrobial agents tested, specifically 13 out of the 16 antimicrobials evaluated. Conclusions: The sensitivity rates of ceftriaxone and meropenem were found to be 0% and 100%, respectively. The predominant bacteria is MRCoNS, which is completely susceptible to tigecycline, vancomycin, linezolid, and nitrofurantoin. Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae is difficult to treat, especially in central nervous system infections when antimicrobials are scarce.

Bacteriological Profile and Antibiogram of Isolates Causing Bloodstream Infection in Children

Objective: (1) To identify and characterize bacterial isolates causing blood stream infection in children. (2) To determine the antibiotic sensitivity pattern of isolates obtained. Materials And Methods: Study design: Descriptive study. Study population: Blood samples collected from pediatric patients aged upto 12 years who are admitted in Government Medical College Kottayam, with clinical features of blood stream infection. Sampling methodology: The sample size of suspected blood stream infection is 345. All pediatric patients with clinical features suggestive of blood stream infection in the study period satisfying inclusion and exclusion criteria will be included in the study. The identification of bacterial pathogens and antimicrobial susceptibility tests were done by conventional and automated methods like VITEK system. Results: Out of 345 study sample population, 46 were culture positive, of which 21(45.7%) were Gram negative isolates and 20(43.4%) were Gram positive. Major isolates obtained were Klebsiella spp (15%), Methicillin Resistant Coagulase negative Staphylococci (15%), followed by Staphylococcus aureus (13%), Coagulase negative Staphylococci (8%) and Acinetobacter baumannii (8%). Klebsiella pneumoniae was resistant to most of the antibiotics tested except meropenem. All isolates of Coagulase negative Staphylococci and Staphylococcus aureus were susceptible to vancomycin and linezolid. Conclusion: Gram negative organisms were predominant pathogens in blood stream infections. Klebsiella pneumoniae, Coagulase negative Staphylococci, Staphylococcus aureus were the most commonly isolated pathogens. Amikacin along with the third generation cephalosporins should be used for empirical treatment of Gram negative sepsis. Vancomycin and linezolid can be used for Gram positive pathogens.

Extending the Structural Diversity of Labdane Diterpenoids from Marine-Derived Fungus Talaromyces sp. HDN151403 Using Heterologous Expression.

Heterologous biosynthesis has become an effective means to activate fungal silent biosynthetic gene clusters (BGCs) and efficiently utilize fungal genetic resources. Herein, thirteen labdane diterpene derivatives, including five undescribed ones named talarobicins A-E (3-7), were discovered via heterologous expression of a silent BGC (labd) in Aspergillus nidulans. Their structures with absolute configurations were elucidated using extensive MS and NMR spectroscopic methods, as well as electronic circular dichroism (ECD) calculations. These labdanes belong to four skeleton types, and talarobicin B (4) is the first 3,18-dinor-2,3:4,18-diseco-labdane diterpene with the cleavage of the C2-C3 bond in ring A and the decarboxylation at C-3 and C-18. Talarobicin B (4) represents the key intermediate in the biosynthesis of penioxalicin and compound 13. The combinatorial heterologous expression and feeding experiments revealed that the cytochrome P450 enzymes LabdC, LabdE, and LabdF were responsible for catalyzing various chemical reactions, such as oxidation, decarboxylation, and methylation. All of the compounds are noncytotoxic, and compounds 2 and 8 displayed inhibitory effects against methicillin-resistant coagulase-negative staphylococci (MRCNS) and Bacillus cereus.

Methicillin-resistant staphylococci in clinical bovine mastitis: occurrence, molecular analysis, and biofilm production.

Staphylococcus aureus is an important pathogen that causes mastitis in cattle, and the emergence of methicillin-resistant S. aureus (MRSA) poses a threat to veterinary and human medicine. The aims of the study were to investigate the prevalence of MRSA and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from clinical mastitis, their ability to form biofilms, and the antimicrobial susceptibility of S. aureus strains. In addition, the Staphylococcal Cassette Chromosome mec (SCCmec) type, spa type and the presence of Panton-Valentine Leucocidin in MRSA were evaluated. A total of 326 staphylococcal strains were screened by multiplex-PCR for S. aureus and Staphylococcus intermedius group (SIG) identification. The S. aureus strains (n = 163) were subjected to phenotypic testing for antimicrobial susceptibility and biofilm formation. Molecular analysis was performed on MRSA mecA-positive strains. Of 163 S. aureus isolates, 142 strains (87.1%) were resistant to at least one antibiotic, and all 19 MRSA strains were resistant to at least four out of five antibiotics tested. All S. aureus strains harboured the icaA gene and were biofilm producers. Nineteen MR-CoNS strains were also isolated. The most prevalent spa types among MRSA were t001 (57.9%) and t037 (31.6%), while one MRSA was type t008 and one was type t041. Most MRSA were SCCmec type I (63.2%) and III (31.6%) and only one strain was type IV. None of the MRSA isolates had the PVL gene. The prevalence of multidrug-resistant S. aureus in bovine mastitis is a serious concern. The finding of MRSA with spa types predominant in humans and infrequent in Italian cows and with SCCmec infrequently found in bovine milk or cheese suggest a human origin of these strains. The ability of MRSA and MR-CoNS involved in bovine mastitis to be transferred to humans and vice versa poses a public health concern.

A Comparison of the Minimum Inhibitory Concentration of Antibiotics in Staphylococcus Species Isolated From Orthopedic and Respiratory Medicine Infections.

Antibiotic susceptibility is very important for the successful treatment of orthopedic infections, particularly for implant-related infections. While the minimum inhibitory concentrations (MICs) of Staphylococcus species were well investigated for the isolates from the respiratory tract, investigations for orthopedic pathogens are very limited. We investigated the antibiotic MIC values of Staphylococcus species isolated from orthopedic infections and compared them with those of respiratory medicine isolatesused as a control. The MICs of vancomycin (VCM), arbekacin (ABK), teicoplanin (TEIC), linezolid (LZD), and rifampicin (RFP) of a total of consecutive 259 (89 orthopedic and 170 respiratory) Staphylococcus speciesisolated in our laboratory from January 2013 to July 2016 were retrospectively reviewed. Differences between the MICs of each antibiotic in orthopedic and respiratory samples were determined. The number of methicillin-sensitive Staphylococcus aureus (MSSA) with a VCM MIC of <0.5 μg/mL among respiratory isolates was significantly higher than that among orthopedic isolates, while those with a MIC of 2 μg/mL were significantly lower (P = 0.0078). The proportion of methicillin-resistant coagulase-negative staphylococci (MRCNS) isolates with a VCM MIC of 2 μg/mL was significantly higher in orthopedic samples than that of methicillin-resistant Staphylococcus aureus (MRSA) (P < 0.001) in respiratory isolates. The proportion of MRCNS orthopedic isolates with an RFP MIC of >2 μg/mL was significantly higher (P = 0.0058) than that of other orthopedic staphylococci. The VCM MICs of Staphylococcus species from orthopedic infections were higher than those of respiratory samples, particularly MRCNS from implant-related samples.

Mupirocin resistance patterns in staphylococcus isolates causing cutaneous and soft-tissue infections: An epidemiological study in a tertiary health-care facility, Dhule, Maharashtra, India

Background: Skin and soft-tissue infections (SSI) caused by Staphylococcus aureus remain a significant concern in both community and hospital settings. Mupirocin resistance among these isolates poses challenges for infection management and control strategies. Aims and Objectives: The aim of this study was to determine the prevalence and patterns of mupirocin resistance among staphylococcus isolates responsible for cutaneous and soft-tissue infections in patients attending a tertiary health-care facility. Along with that, the study investigated into mupirocin resistance prevalence and identified risk factors. Materials and Methods: A prospective study was conducted at a medical college, including 256 non-consecutive staphylococcal isolates from SSI. Antibiotic susceptibility testing was performed using Clinical and Laboratory Standards Institute recommended methods. Mupirocin resistance was determined through disk diffusion testing using 5 μg and 200 μg Mupirocin disks for low-level and high-level resistance, respectively. Results: Among the samples, 16.4% were methicillin-resistant S. aureus (MRSA) and 9.37% were methicillin-resistant coagulase-negative staphylococci. Mupirocin high-level resistance was found in 16.6% of S. aureus isolates, and mupirocin low-level resistance in 19% of MRSA isolates. The prevalence of resistance was lower in inpatient departments compared to outpatient departments. Associations were observed between resistance and patient demographics, history of mupirocin use, surgical site infections, hospitalization history, and diabetes. Conclusion: Mupirocin resistance presents a multifaceted challenge in the context of both patient demographics and clinical settings. The prevalence of resistance was influenced by factors such as patient age, gender, and prior mupirocin usage.

Prevalence of methicillin and clindamycin resistant Staphylococcus species at a tertiary hospital in Tanzania: Implications for antibiotic stewardship and infection management

Methicillin and clindamycin resistance (constitutive and inducible) pose a common clinical challenge in treating Staphylococcal infections. This cross-sectional study, conducted at Muhimbili National Hospital (MNH) in Tanzania from April to June 2023, to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and clindamycin-resistant Staphylococcus (S.) species by using a cefoxitin disk (30 μg) and the D-test method as per CLSI 2022 guidelines. Of the 361 clinical samples, 125 (34.6%) were culture-positive. Among Staphylococcus spp., S. aureus was 6% (12/125), while 33.6% (42/125) were coagulase-negative staphylococci (CoNS). Among the isolated S. aureus, 75% were resistant to methicillin, while 66.7% of the CoNS were resistant to methicillin. Further, 92% (11/12) of the S. aureus isolates were resistant to erythromycin, and 50% (6/12) were resistant to clindamycin. Among the CoNS, 83% (35/42) were resistant to erythromycin, and 52% (22/42) were resistant to clindamycin. The proportion of inducible macrolides lincosamide streptogramin B resistance (iMLSB), constitutive macrolides lincosamide streptogramin B resistance (cMLSB), and macrolides lincosamide streptgramin B methicillin susceptible (MS) phenotypes among S. aureus isolates was 16.7%, 41.7%, and 33.3%, respectively, and among CoNS was 19%, 35.7%, and 28.6%, respectively. The overall prevalence of iMLSB and cMLSB phenotypes was 18.5% (10/54) and 37% (20/54), respectively. Comparatively, MRSA had more resistance to ciprofloxacin than methicillin-susceptible S. aureus (MSSA) (88.9% vs. 33.3% p = 0.027), while methicillin-resistant coagulase-negative staphylococci (MR-CoNS) had significantly higher resistance to gentamicin (35.7% vs. 7.1% p= 0.005), and trimethoprim-sulfamethoxazole (78.6% vs. 50% p=0.007) than methicillin-susceptible coagulase-negative staphylococci (MS-CoNS). The high prevalence of methicillin and inducible clindamycin resistance in this study points out a potential rise in treatment failures, prolonged hospitalization, and limited treatment options. Thus, emphasizes the importance of antibiotic stewardship and laboratory-guided antibiotic decisions. To address the growing challenge of antibiotic resistance in Tanzania, it is advisable to implement stringent public health measures, including monitoring antibiotic usage, conducting educational initiatives, and raising awareness among patients and healthcare professionals.

Clinical Characteristics and Risk Factors for Bloodstream Infections in Children with Cancer: A Report from a Pediatric Hematology Oncology Unit.

Infections are a major cause of morbidity and mortality in children with haematologic malignancies and solid tumors as well as those undergoing hematopoietic stem cell transplantation (HSCT). The purpose of our study was to record the epidemiological characteristics and outcomes of bacteremias, focusing on pathogens, as well as risk factors and mortality rates in patients of a pediatric hematology-oncology unit from Northern Greece. A retrospective analysis was conducted, which included all positive blood cultures from pediatric hematology oncology patients aged from 1 to 16 years old admitted to the Pediatric and Adolescent Hematology Oncology Unit of AHEPA University Hospital of Thessaloniki between January 2014 and December 2018. Data were collected from patients' printed and electronic medical records. 73 episodes of bacteremias were identified (41% male and 32% female with a ratio of 1.28:1; median age 6.5 years; 13.7% solid tumor, 72.6% acute lymphoblastic leukemia, 13.7% acute myeloid leukemia, and 95.8% with an indwelling permanent catheter). 49.3% of the isolates were Gram-positive bacteria and 50.7% Gram-negative, and the ratio of Gram-negative to Grampositive was 1.02. Coagulase-negative staphylococci were most frequent (39.7%), followed by E. coli (17.8%) and Klebsiella pneumoniae (17.8%). Out of all Gram-negatives, 13.5% carbapenemase producers and 8.1% ESBL-producers were found. In relation to Gram-positive, 79.3% were identified as methicillin-resistant CoNS. During the study period, 10.9% of indwelling catheters were removed, and 2.73% of episodes resulted in ICU transfer. The 3-month mortality rate was 8.2%. This study demonstrated an almost equal distribution of Gram-positive and Gramnegative bacteremias in total in this population but with an increase in the isolation of Grampositive bacteria over the last years, which is consistent with other similar studies in this patient group. Knowledge of the local epidemiology and bacterial antimicrobial resistance is important to prevent and timely treat these life-threatening infections in immunocompromised pediatric oncology patients.

Methicillin-Resistant Staphylococcus aureus and Coagulase-Negative Staphylococcus from School Dining Rooms in Argentina.

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes an important cause for concern in the field of public health, and the role of the food chain in the transmission of this pathogen and in antimicrobial resistance (AMR) has not yet been defined. The objectives of this work were to isolate and characterize coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS), particularly S. aureus, from school dining rooms located in Argentina. From 95 samples that were obtained from handlers, inert surfaces, food, and air in 10 establishments, 30 Staphylococcus strains were isolated. Four isolates were S. aureus, and the remaining ones (N = 26) belonged to 11 coagulase-negative species (CoNS). The isolates were tested for susceptibility to nine antibiotics. The presence of genes encoding toxins (luk-PV, sea, seb, sec, sed, and see), adhesins (icaA, icaD), and genes that confer resistance to methicillin (mecA) and vancomycin (vanA) was investigated. The resistance rates measured for penicillin, cefoxitin, gentamicin, vancomycin, erythromycin, clindamycin, levofloxacin, trimethoprim-sulfamethoxazole, and tetracycline were 73%, 30%, 13%, 3%, 33%, 17%, 13%, 7%, and 7% of the isolates, respectively. Seventeen AMR profiles were detected, and 11 isolates were multidrug resistant (MDR). Seven methicillin-resistant Staphylococcus isolates were detected in the hands of handlers from four establishments, two of them were MRSA. Two S. aureus isolates presented icaA and icaD, another one, only icaD. The gene vanA was found in two isolates. In relation to S. aureus, resistance to vancomycin but not to gentamicin was detected. School feeding plays a key role in the nutrition of children, and the consumption of food contaminated with MRSA and vancomycin-resistant S. aureus (VRSA) can be a serious threat to health. In particular, it was detected that the handlers were the source of MRSA, VRSA, MR-CoNS (methicillin-resistant coagulase-negative Staphylococcus), and MDR isolates. The results obtained indicate that the vigilance of this pathogen in school dining rooms should be extreme.