Coagulase-negative Staphylococci Isolates Research Articles

Incidence of Coagulase Negative Staphylococci in Various Clinical Samples in Tertiary Care Hospital, Nepal

Objectives: To determine incidence of coagulase negative Staphylococci (CoNS) in various clinical samples along with the study of their multi drug resistance, methicillin resistance and biofilm formation. Methods: A hospital based cross-sectional study was conducted which included 1875 clinical samples. The isolation and identification of isolates was done following standard microbiological protocol. The CoNS were identified phenotypically on the basis of gram staining, slide and tube coagulase test and through various carbohydrates fermentation tests. Antibiotic susceptibility test was done by Kirby Bauer disk diffusion method (Clinical and Laboratory Standards Institute 2020) whereas biofilm production was determined by Tissue Culture Plate (TCP) technique. Results: A total of 32 CoNS, comprising of 6 species were identified. S. epidermidis (43.8%) was the most common species isolated followed by S. saprophyticus (28.1%), S. haemolyticus (15.6%), S. hominis (6.3%), S. lugdunensis (3.1%) and S. cohini (3.1%). Further, 27 (84.4%) of CoNS were found to be multidrug resistant, 22 (68.8%) methicillin resistant and 8 (25%) showed positive D- test. Strong biofilm production was detected in 9 (28.1%) isolates of CoNS, 10 (31.3%) were moderate biofilm producers and 13 (40.6%) non/weak biofilm producers. The equal distribution, 9 (33.3%) each of strong, moderate and non/weak biofilm producers were found among 27 isolates of MDR. Among 22 methicillin resistant isolates, 9 (40.9%), 7 (31.8%) and 6 (27.3%) were strong, moderate and non/ weak biofilm producers respectively. All isolates were sensitive against Linezolid followed by Cotrimoxazole. Conclusion: The increasing multi drug resistance among CoNS should be rationally approached with the use of proper antibiotics while treating the patients.

Species distribution and antimicrobial susceptibility pattern of coagulase-negative staphylococci isolated from clinical specimens at a tertiary care hospital

Background and objectives: Coagulase-negative staphylococci (CoNS) are considered important causative agents of hospital acquired infection. These organisms are found in various clinical specimens from hospitalized patients. Present study was carried out to determine the species distribution and antimicrobial susceptibility pattern of CoNS isolated from clinical specimens at a tertiary care hospital. Materials and methods: CoNS isolated from various clinical samples were included in this study. The isolates were identified by colony morphology, Gram’s staining, catalase and coagulase tests. Further differentiation of species was performed by susceptibility to novobiocin, urease activity and ornithine decarboxylase test. Antibiotic susceptibility testing was performed according to the Clinical and Laboratory Standard Institute (CLSI) guidelines. Results: Total 108 isolates of CoNS were included and analysed. Out of 108 CoNS, S. epidermidis was the most common species (36.1%) followed by S. saprophyticus (23.1%), S. hemolyticus (17.6%), S. hominis (13%) and S. lugdunensis (10.2%). Most of the isolates showed resistance to penicillin, oxacillin, amoxycillin, erythromycin, ciprofloxacin and ofloxacin. All the isolates were sensitive to vancomycin. Conclusions: CoNS emerged as an important nosocomial pathogen and should not be neglected as contaminant. High rate of antimicrobial resistance warrants susceptibility testing prior to the treatment of CoNS. IMC J Med Sci. 2024; 18(1):010. DOI: https://doi.org/10.55010/imcjms.18.010 *Correspondence: Sabiha S Tamboli, Department of Microbiology, Parbhani Medical College and RP Hospital Research Institute, Pathri Road, Parbhani, Maharashtra, India. Email: sabihatamboli77@gmail.com

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.

Utility of Echocardiogram in Neutropenic Patients with Gram Positive Bacteremia: A Retrospective Study

Introduction: Hemato-oncology patients are vulnerable to bloodstream infections (BSI) due to their immunocompromised and neutropenic state, and the common use of intravascular catheters. The risk of infective endocarditis (IE) among non-neutropenic patients with gram positive bacteremia is substantial, however the risk is considered to be lower among neutropenic patients, though data is limited. We aimed to evaluate the incidence of IE among neutropenic hemato-oncology patients' cohort, and to explore the yield of echocardiogram in this specific population. Methods: A single center, retrospective study. Between 01/2007 and 12/2019, hospitalized patients in the Hematology department consisting of the hemato-oncology and bone marrow transplantation units were included, if they had positive blood cultures for specific organisms known to cause IE while neutropenic. Patient characteristics, results and timing of blood cultures and echocardiogram obtained during hospitalization were collected. Results: Two hundred seventy-four patients had positive blood cultures with pathogens known to be associated with IE. Overall, 340 isolates have been identified. After excluding 57 coagulase negative staphylococcus (CONS) isolates which were suspected as a contamination (identified in a single collection), 241 patients were included with 283 isolates. CONS were the most commonly isolates found, followed by streptococcus viridans, comprising 31.4% (89) and 24.3% (69) of isolates, respectively. Trans thoracic echocardiography (TTE) was performed in 108 (45%) patients overall, of which 14 (5.8%) had additional trans esophageal echocardiogram (TEE). Only one case of IE was diagnosed in our series, of a forty-seven-year-old female patient with a diagnosis of multiple myeloma in relapse after autologous stem cell transplantation. The patient presented with a stroke caused by septic emboli, fever and streptococcus viridans bacteremia. Lab works showed neutropenia of 0K/micl and thrombocytopenia of 8K/micl. TTE and TEE failed to demonstrate valvular pathology consistent with IE in this case. Valvular vegetations have not been identified on TTE nor on TTE in any other case as well. Conclusion In our experience, the yield of echocardiogram in hemato-oncological neutropenic patients with gram positive bacteremia is extremely low, owing to reduced probability of IE in this population, and thus could be avoided in most cases.

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.

2408. Is Shorter Antibiotic Treatment Feasible in Patients with Cardiac Implantable Electronic Devices (CIED) Infections? Impact of Treatment Duration on 6-Month Recurrence and Mortality

Abstract Background Aim of this study is to compare the 6-month outcomes (recurrence and mortality) of patients with cardiac implantable electronic device (CIED) infections treated with short (SHORT, &amp;lt;14 days) or long (LONG, &amp;gt;14 days) duration of antimicrobial therapy after device removal. Methods Retrospective cohort study of patients hospitalized at IRCCS San Raffaele Hospital (Milan, Italy) from June 2011 to June 2021, who underwent device removal for CIED infection. Patients with pocket and lead infections were included, while valve endocarditis and Staphylococcus aureus infection were excluded. The characteristics of patients in the SHORT and LONG groups were compared using the chi-square test for categorical variables and the Mann-Whitney U-test for continuous variables. A propensity score (PS) was calculated using a logistic regression that considered duration of therapy as the dependent variable; the association between patients’ characteristics and outcomes was evaluated with logistic regression analysis. Results The characteristics of the 150 included patients are described in table 1, the microbial etiology in table 2. Patients in the SHORT compared to the LONG group were older (75 [65-80] vs 69 [62-77], p-value=0.047), had a higher Charlson comorbidity index (5 [3-6] vs 4 [3-5], p-value=0.021), had less frequent isolation of coagulase-negative staphylococci (CoNS; 46.7% vs 68.9%, p-value=0.006), and an unknown etiology (36.7% vs 13.3%, p-value=0.001). Moreover, the duration of antimicrobial treatment after device removal was shorter (13 [9-14] vs 20 [16-29] days, p-value&amp;lt; 0.001). At 6 months, recurrence and mortality were not significantly different between the SHORT and the LONG group (recurrences: 2 [3.7%] vs 5 [6.7%], p-value=0.464; mortality: 2 [3.7%] vs 3 [4.0%], p-value=0.931), At logistic regression analysis (table 3 and table 4) adjusted for PS, treatment duration was not significantly associated with either recurrence (odds ratio [OR] 0.524; 95% confidence interval [95%CI] 0.084-3.263) or mortality (OR 1.402; 95%CI 0.185-10.635). Conclusion A shorter duration of antimicrobial treatment after device removal may be an effective approach for treating patients with CIED infections. Disclosures Antonella Castagna, MD, Bristol-Myers Squibb: consultancy payments and speaking fees|Gilead: consultancy payments and speaking fees|Janssen-Cilag: consultancy payments and speaking fees|Merck Sharp &amp; Dohme: consultancy payments and speaking fees|ViiV Healthcare: consultancy payments and speaking fees

Nasal staphylococci microbiota and resistome in healthy adults in La Rioja, northern Spain: High frequency of toxigenic S. aureus and MSSA-CC398 subclade

This study determined the nasal staphylococci diversity and characterized their resistome, with a focus on the mobilome of methicillin-susceptible Staphylococcus aureus (MSSA)-CC398 subclade from healthy adults in La Rioja (northern Spain). Nasal staphylococci recovered from 57 healthy individuals (HI) were identified (MALDI-TOF-MS) and their antimicrobial resistance, virulence determinants and genetic lineages were studied. The relatedness of MSSA-CC398 isolates was assessed by core-genome single-nucleotide-polymorphisms (SNPs). One-hundred-forty-three non-repetitive staphylococci were obtained from most HI (98.2%), of which S. epidermidis (87.7%) and S. aureus (36.8%) were the predominant species. About 15% of the 27 S. aureus and 30.1% of the 116 coagulase-negative staphylococci (CoNS) isolates presented a multidrug resistance (MDR) phenotype. All S. aureus isolates were MSSA but 30.2% of CoNS isolates were mecA-positive and carried SCCmec types III, IV, and V. The highest non-beta-lactam resistance (frequency/genes) in S. aureus and CoNS were: erythromycin-clindamycin-inducible (25.9%/ermT, ermC) and mupirocin (30.1%/mupA), respectively. About 85% of S. aureus isolates carried relevant virulence genes. Eight clonal complexes (CCs) of MSSA were identified, of which CC398 was the predominant (33.3%). About 78% of the CC398 isolates harboured rep13-bound ermT gene, however, one carried a rep10-bound ermC gene. Only the ermT-positive MSSA-CC398 isolates were closely related (<50 SNPs) and carried the φSa3. Diverse MDR-S. epidermidis isolates were identified which included the lineages ST59 and ST210. The high rate of toxigenic S. aureus and of MSSA-CC398 subclade highlight the ability of HI to carry and transmit virulent isolates. Moreover, the high frequency of MDR-CoNS, often linked with SCCmec, needs to be monitored for their potential human health implications.

The relevance of coagulase-negative Staphylococcus isolates in blood culture in the context of a tertiary neonatal unit from East India

Background: Coagulase-negative Staphylococcus (CoNS) are known commensals and often contaminate neonatal blood cultures. Their unique ability to form biofilms, however, helps them evade immune mechanisms and antibiotics and cause neonatal sepsis (NS) in hospitalized neonates. True or probable Coagulase-negative Staphylococcus blood stream infection (CoNS BSI) must be differentiated from contaminants so that antibiotics are used judiciously and hospital stay is minimized. Aims and Objectives: The primary objective of the study was to estimate the proportion of NS and contaminants among CoNS-positive blood cultures in the index neonatal unit and the host and health-care variables associated with CoNS BSI. The secondary objective was to estimate the susceptibility of CoNS isolates to antibiotics used. Materials and Methods: This was a retrospective study from digital records, from January 2018 to December 2022. Results: 25% of CoNS isolates were associated with NS (health-care infections) and 75% were contaminants. Over 90% of CoNS BSI was associated with central lines (CLs) and prolonged hospital stay. All isolates were resistant to oxacillin while resistance to gentamicin rose annually to over 68%. Susceptibility to linezolid and vancomycin was present, but a few strains were resistant to them. Conclusion: CoNS were an important cause of NS in the index hospital. Prolonged hospital stays and CLs were associated with increased incidence of CoNS sepsis and must be minimized where possible. Antibiotic resistance was high, and reserve drugs could also become ineffective.

Linezolid resistance in coagulase negative Staphylococci isolates and the related genes in intensive care unit patients in a University Hospital in Egypt

Linezolid resistance in coagulase negative Staphylococci isolates and the related genes in intensive care unit patients in a University Hospital in Egypt

Isolation, characterization, and fermentation potential of coagulase-negative Staphylococci with taste-enhancing properties from Chinese traditional bacon

No proprietary starter cultures for crafting Chinese bacon. This study aimed to isolate Coagulase-negative Staphylococci (CNS) from Chinese bacon, identify their species, and evaluate their ability to produce biogenic amines (BAs), peptides, free amino acids (FAAs), and degrade proteins. Twenty-one isolates were deficient in hemolysis, DNase, and coagulase activities, and exhibited low amino acid decarboxylase activity. Further characterization revealed 11 CNS species showing protease, lipase, or nitrate reductase activities. Specifically, S. cohnii WX-M8 was able to degrade both sarcoplasmic and myofibrillar proteins, while S. saprophyticus MY-A10 was found to only degrade myofibrillar proteins. Both were able to reduce the BAs and increase the content of peptides around day 3. The meat fermented by these two CNS contained FAAs that are more conducive to taste formation, such as Glu and Asp, and reduced the content of bitter FAAs. These findings will provide insights into the use of CNS for Chinese bacon.

Identification and characterization of SCCmec typing with psm-mec positivity in staphylococci from patients with coagulase-negative staphylococci peritoneal dialysis-related peritonitis

BackgroundPeritonitis is the most important complication of peritoneal dialysis (PD) and coagulase-negative staphylococci (CNS) are a frequent cause of dialysis-related infections. The association between SCCmec typing with psm-mec positivity in staphylococci and PD-related infections has not been identified. We aim to investigate the molecular epidemiology of CNS isolated from PD-peritonitis in a single Chinese center, focusing on the genetic determinants conferring methicillin resistance.MethodsWe collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected.ResultsTen CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene.ConclusionsThe majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance.

The emergence of multidrug-resistant Gram-positive bloodstream infections in India - a single center prospective cohort study.

Gram-positive bloodstream infections (BSIs) are an emerging health concern, especially in resource-limited settings. There is a paucity of data regarding the antimicrobial resistance (AMR) pattern of Gram-positive BSIs. The rise in multidrug-resistant infections further convoluted antibiotic selection. We aimed to assess the incidence, clinical and microbiological profile, antimicrobial resistance (AMR) and outcome in Gram-positive BSIs. This was a single-center prospective study conducted at a tertiary care hospital in Western India. All patients (age ≥18 years) with culture-proven Gram-positive BSIs were included. Data were collected on all patients' demography, risk factors, AMR and clinical outcome. A total of 210 clinically significant isolates were grown from July 2020 to December 2021. The incidence of Gram-positive BSIs was 29% (n=61); 55.9% of cases were healthcare-associated, while 44.1% were community-acquired. Coagulase-negative staphylococci (CoNS) were the major isolates (36.1%), followed by Enterococcus spp. (27.9%), methicillin-susceptible Staphylococcus aureus (MSSA) (18%) and methicillin-resistant Staphylococcus aureus (MRSA) (14.7%). The proportion of vancomycin and teicoplanin-resistant CoNS isolates was 13.6% and 19%. Among Enterococcus isolates, the proportion of vancomycin-resistant enterococci (VRE) and linezolid-resistant enterococci (LRE) were 11.8% and 5.9%. The overall mortality in Gram-positive BSIs was 42.6%. Older age, MRSA infection, septic shock, and high NLR were significantly associated with mortality. On the Cox regression model, age ≥65 years (HR: 2.5; 95%CI: 1.1-5.8; p=0.024) and MRSA infection (HR: 3.6; 95%CI: 1.5-8.5; p=0.021) were found as independent predictors of 30-day mortality. This study found substantial mortality with Gram-positive BSIs, especially MRSA infections. Moreover, the emergence of VRE and LRE is also alarming. Active surveillance of AMR and evaluation of mortality predictors may help overcome the therapeutic challenges in managing BSIs.

The frequency of adherence, biofilm-associated, Arginine Catabolic Mobile element genes, and biofilm formation in clinical and healthcare worker coagulase-negative staphylococci isolates

BackgroundHealthcare workers may pave the way for increased infections in hospitalized patients by coagulase-negative staphylococci (CoNS). Biofilm formation and antibiotic resistance are the major problems posed by CoNS in nosocomial infections. In this study, we determined biofilm production level and the distribution of biofilm-associated and virulence genes, including icaADBC, aap, bhp, atlE, embp, and fbe, as well as IS256, IS257, mecA, and ACME clusters (arc-A, opp-3AB) among 114 clinical (n = 57) and healthcare workers (n = 57) CoNS isolates in Kerman, Iran.ResultsIn this study, more than 80% (n = 96) of isolates were methicillin-resistant CoNS (MR-CoNS). Out of 114 isolates, 33% (n = 38) were strong biofilm producers. Strong biofilm formation was found to be significantly different between clinical and healthcare workers’ isolates (P < 0.050). In addition, 28% (n = 32) of isolates were positive for icaADBC simultaneously, and all were strong biofilm producers. The prevalence of icaADBC, mecA, bhp, fbe, and IS256 in clinical isolates was higher than that in healthcare workers’ isolates (P < 0.050). A significant relationship was observed between clinical isolates and the presence of icaADBC, mecA, bhp, and IS256. Although these elements were detected in healthcare workers’ isolates, they were more frequent in clinical isolates compared to those of healthcare workers.ConclusionsThe high prevalence of ACME clusters in healthcare workers’ isolates and biofilm formation of these isolates partially confirms the bacterial colonization in the skin of healthcare workers. Isolating MR-CoNS from healthcare workers’ skin through similar genetic elements to clinical isolates, such as icaADBC, mecA, and IS256, calls for appropriate strategies to control and prevent hospital infections.

Characterisation of antibiotic resistant Staphylococcus species and molecular identification of mecA and toxic shock syndrome toxin-1 (tsst-1) genes of Staphylococcus aureus isolates from cows' milk

Staphylococcus aureus (S. aureus) is one of the most important causes of foodborne illness. Due to the interest of people to use traditional dairy products, especially milk, in the current descriptive study the frequency of S. aureus, antibiotic resistance pattern and presence of toxic shock syndrome toxin-1 gene (tsst-1 gene) in these isolated strains was investigated. Thirty-nine strains (26%) of S. aureus were identified from the samples studied, of which 6 (15.38%) were resistant to methicillin, and 9 (23.07%) were positive for mecA gene. Also, 31 (20.7%) coagulase-negative staphylococci isolates were identified. Out of the 39 strains of S. aureus, the presence of tsst gene was detected in 1 strain (2.56%). Therefore, S. aureus contamination indicates a risk to public health and can be significantly controlled using a high level of hygiene and professional training in the handling of raw milk.

Antibiotic sensitivity pattern of coagulase negative staphylococci in a tertiary care hospital of Southern Rajasthan

Coagulase negative staphylococci have been recognized as one of the important cause of hospital acquired infections in recent past. It has become difficult to manage these infections due to emergence of multidrug resistance to them. The aim of this study was to determine antibiotic sensitivity trend of all Coagulase negative Staphylococci isolates using modified Kirby- Bauer disk diffusion technique. To assess the antibiotic sensitivity for coagulase negative staphylococci, Kirby-Bauer disc diffusion method on Muller-Hinton agar was used. The study findings were interpreted on the basis of CLSI standards. All coagulase negative staphylococci isolates were given a predetermined panel of antibiotics. Methicillin-resistant coagulase negative staphylococci were identified using Cefoxitin disk. The sensitivity to Linezolid, Vancomycin and Rifampicin was found in all 500 isolates of coagulase negative staphylococci in our study. However, they were resistant to Penicillin G (65%), Cefoxitin (56%), Ciprofloxacin (57%), Levofloxacin (32%), Gentamicin (21%), Erythromycin (67%), Clindamycin (60%), Cotrimoxazole (51%) Tetracycline (9%). As CoNS have emerged as an important agent of hospital acquired infections, hence there is need of identification, speciation and resistance pattern of isolates for better management of patients.

From Hospital to Community: Exploring Antibiotic Resistance and Genes Associated with Virulence Factor Diversity of Coagulase-Positive Staphylococci.

Coagulase-positive staphylococcus (CoPS), including methicillin-resistant Staphylococcus aureus (MRSA), poses a global threat. The increasing prevalence of MRSA in Saudi Arabia emphasizes the need for effective management. This study explores the prevalence of virulence-associated genes and antibiotic resistance patterns in CoPS. Nasal swabs from 200 individuals were collected, and standard protocols were used for the isolation, identification, and characterization of CoPS and coagulase-negative staphylococci (CoNS). Additionally, antimicrobial susceptibility testing and PCR were conducted. Bacterial growth was observed in 58.5% of participants, with 12% positive for CoPS and 30% positive for CoNS. Hospital personnel carriers showed a significantly higher proportion of CoNS compared with non-hospital personnel carriers. Non-hospital personnel CoPS strains displayed higher sensitivity to oxacillin than hospital personnel strains. Cefoxitin exhibited the highest sensitivity among β-lactam antibiotics. All isolates were sensitive to trimethoprim/sulfamethoxazole, rifampin, and quinupristin. Polymerase chain reaction analysis detected methicillin resistance genes in both non-hospital and hospital personnel MRSA strains. The coa and spa genes were prevalent in MRSA isolates, while the Luk-PV gene was not detected. A high prevalence of CoPS and CoNS was observed in both non-hospital and hospital personnel carriers. Occupational risk factors may contribute to the differences in the strain distribution. Varying antibiotic susceptibility patterns indicate the effectiveness of oxacillin and cefoxitin. Urgent management strategies are needed due to methicillin resistance. Further research is necessary to explore additional virulence-associated genes and develop comprehensive approaches for CoPS infection prevention and treatment in Saudi Arabia.

Antimicrobial resistome of coagulase-negative staphylococci from nasotracheal cavities of nestlings of Ciconia ciconia in Southern Spain: Detection of mecC-SCCmec type-XI-carrying S. lentus

The antimicrobial resistance (AMR) genes of 268 non-duplicated coagulase-negative staphylococci (CoNS) previously obtained from nasotracheal cavities of nestling storks were characterized. They included S. sciuri isolates (n = 191), and non-sciuri-CoNS isolates (NSc-CoNS, n = 77). All S. sciuri carried the intrinsic salA gene (for clindamycin-resistance) and so, clindamycin was not considered for general analysis in this species. About 71.7%/41.6% of the S. sciuri/NSc-CoNS isolates were susceptible to all antibiotics tested; moreover, 14.1%/16.9% and 3.1%/20.8% of S. sciuri/NSc-CoNS showed single antibiotic resistance and multidrug resistance (MDR) phenotype, respectively. Of the ten mecA-positive CoNS isolates, six were associated with SCCmec types-III, -IV or -V elements. Remarkably was the detection of one MDR-S. lentus isolate carrying both mecA and mecC genes, as well as the SCCmec type-XI element. MDR-CoNS was relatively higher in nestlings of parent storks foraging in landfills (21.3%) than those in natural areas (9.7%) (χ2 = 3.421, df=1, p = 0.064). AMR phenotypes (and genes detected) include penicillin (blaZ, blaARL), erythromycin-clindamycin-constitutive (ermA, ermC, ermT), clindamycin (lnuA, salA, vgaA), erythromycin (msrA, mphC), tetracycline (tetK, tetL, tetM), tobramycin (ant4′), tobramycin-gentamicin (aac6′-aph2″), sulfamethoxazole-trimethoprim (dfrA, dfrG, dfrK), chloramphenicol (fexA, fexB, catPC221), and mupirocin (mupA). Interestingly, one S. epidermidis isolate carried the ermT gene. About 29.9% of nestlings harboured more than one non-duplicated CoNS (with varied 2–5 AMR profiles). This study demonstrated that most of the CoNS isolates were susceptible to all the antibiotics tested (63.1%). However, AMR genes of public health importance were found, including the mecC-mediated methicillin resistance trait.

Antimicrobial resistance and virulence profiles of staphylococci isolated from clinical bovine mastitis.

Staphylococci, mainly including Staphylococcus aureus and coagulase-negative staphylococci (CNS), are one of the most common pathogens causing bovine mastitis worldwide. In this study, we investigated the antimicrobial resistance and virulence profiles of staphylococci from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. Antimicrobial resistance was determined by disc diffusion combined with E-test method. Genes of antimicrobial resistance and virulence factors were determined by PCR. A total of 332 staphylococcal isolates were confirmed from 1,519 mastitic milk samples, including 172 S. aureus and 160 CNS isolates. Fifteen CNS species were identified, with S. chromogenes being the most frequent found (49.4%), followed by S. equorum (13.8%). Noticeably, 2 S. agnetis isolates were found among the CNS isolates. To our knowledge, this is the first report documenting the presence of S. agnetis from bovine mastitis in China. The S. aureus and CNS isolates showed high resistance against penicillin, followed by erythromycin and tetracycline. Multidrug resistance was found in 11.6 and 16.3% of the S. aureus and CNS isolates, respectively. Resistance to penicillin was attributed to the presence of blaZ, erythromycin resistance to ermC (alone or combined with ermB) and tetracycline resistance to tetK (alone or combined with tetM). Notably, one S. equorum isolate and one S. saprophyticus isolate were both methicillin-resistant and mecA positive. Additionally, all S. aureus isolates carried the adhesin genes fnbpA, clfA, clfB, and sdrC, and most of them contained cna and sdrE. Conversely, only a few of the CNS isolates carried clfA, cna, and fnbA. Regarding toxin genes, all S. aureus isolates harbored hlb, and most of them were hlg positive. The lukE-lukD, lukM, sec, sed, sei, sen, seo, tst, seg, seh, and sej were also detected with low frequencies. However, no toxin genes were observed in CNS isolates. This study reveals high species diversity of staphylococci from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. The findings for the genetic determinants of antimicrobial resistance and virulence factor provide valuable information for control and prevention of staphylococcal bovine mastitis.

Baseline prevalence of antimicrobial resistance in patients who develop a surgical site infection in hip and knee replacements: A brief report

Prior to clean surgeries, decolonization with topical antimicrobials may lead to an increase in antimicrobial resistance. To provide a baseline prevalence of resistance to topical antimicrobials, in Alberta, specimens were collected from surgical site infections following hip and knee replacements. Among 81 samples with complex surgical site infections, in 43 specimens Staphylococcus species were isolated. Only coagulase-negative staphylococci isolates carried resistance genes with 10 carrying the gene qac and 6 carrying the MupA gene.

Microbiology of Eye Infections at the Massachusetts Eye and Ear: An 8-Year Retrospective Review Combined With Genomic Epidemiology

Ocular bacterial infections are important causes of morbidity and vision loss. Early antimicrobial therapy is necessary to save vision, but their efficacy is increasingly compromised by antimicrobial resistance (AMR). We assessed the etiology of ocular bacterial infections seen at Massachusetts Eye and Ear and investigated the molecular epidemiology and AMR profiles of contemporary isolates. Laboratory investigation. We used a combination of phenotypic tests and genome sequencing to identify the predominant lineages of leading ocular pathogens and their AMR profiles. A total of 1601 isolates were collected from 2014 to 2021, with Staphylococcus aureus (n=621), coagulase-negative staphylococci (CoNS) (n=234), Pseudomonas aeruginosa (n=213), Enterobacteriaceae (n=167), and Streptococcus pneumoniae (n=95) being the most common. Resistance was high among staphylococci, with methicillin resistance (MR) detected in 28% of S aureus and 39.8% of CoNS isolates. Multidrug resistance (MDR) was frequent among MR staphylococci (MRSA 60%, MRCoNS 76.1%). The population of S aureus isolates consisted mainly of 2 clonal complexes (CCs): CC8 (26.1%) and CC5 (24.1%). CC5 strains carried a variety of AMR markers, resulting in high levels of resistance to first-line therapies. Similarly, the population of ocular Staphylococcus epidermidis was homogenous with most belonging to CC2 (85%), which were commonly MDR (48%). Conversely, ocular S pneumoniae, P aeruginosa, and Enterobacteriaceae were often susceptible to first-line therapies and grouped into highly diverse genetic populations. Our data showed that ocular bacterial infections in our patient population are disproportionately caused by strains that are resistant to clinically relevant antibiotics and are associated with major epidemic genotypes with both community and hospital associations.