Clinical relevance of Staphylococcus saccharolyticus detection in human samples: a retrospective cohort study.

PURPOSE: To characterize the clinical relevance of S. saccharolyticus and to identify criteria to distinguish between infection and contamination. METHODS: We retrospectively investigated clinical features of patients with S. saccharolyticus detection between June 2009 and July 2021. Based on six criteria, infection was considered likely for patients with a score from 3 to 6 points, infection was considered unlikely for patients with a score from 0 to 2 points. We performed group comparison and logistic regression to identify factors than are associated with likely infection. In addition, whole genome sequencing (WGS) of 22 isolates was performed. RESULTS: Of 93 patients in total, 44 were assigned to the group "infection likely" and 49 to the group "infection unlikely". Multiple regression analysis revealed "maximum body temperature during hospital stay" to have the strongest predictive effect on likely infection (adjusted odds ratio 4.40, 95% confidence interval 2.07-9.23). WGS revealed two different clades. Compared to isolates from clade A, isolates from clade B were more frequently associated with implanted medical devices (3/10 vs. 9/12, p = 0.046) and a shorter time to positivity (TTP) (4.5 vs. 3, p = 0.016). Both clades did neither differ significantly in terms of causing a likely infection (clade A 7/10 vs. clade B 5/12, p = 0.23) nor in median length of hospital stay (28 vs. 15.5 days, p = 0.083) and length of stay at the ICU (21 vs. 3.5 days, p = 0.14). CONCLUSION: These findings indicate that S. saccharolyticus can cause clinically relevant infections. Differentiation between infection and contamination remains challenging.

Prevalence, genetic characteristics, and antimicrobial resistance of staphylococcal isolates from oral cavity and skin surface of healthy individuals in northern Japan.

BACKGROUND: Oral cavity is an ecological niche for colonization of staphylococci, which are a major bacterial species causing community-acquired infections in humans. In this study, prevalence, and characteristics of staphylococci in oral cavity and skin of healthy individuals were investigated in northern Japan. METHODS: Saliva from oral cavity and swab from skin surface of hand were collected and cultured on selective media. Species of the isolates were identified genetically, and ST was determined for S. aureus and S. argenteus. Genes associated with antimicrobial resistance were detected by PCR. RESULTS: Among 166 participants, a total of 75 S. aureus isolates were obtained from 61 individuals (37 %), and recovered more frequently in oral cavity (n = 48) than skin (n = 27). Among 23 STs identified in S. aureus isolates, ST8 (CC8), ST15 (CC15), and ST188 (CC1) were the most common (10 isolates each), with STs of CC1 being dominant (17 isolates). Methicillin-resistant S. aureus (MRSA) was isolated in the skin of two individuals and belonged to ST1 and ST6. Resistance to erythromycin and gentamicin associated with erm(A) and aac(6')-Ie-aph(2")-Ia, respectively, was more commonly found in ST5 and ST8 isolates. One S. argenteus isolate (ST2250, mecA-negative) was recovered from oral cavity of a participant (0.6 %). A total of 186 isolates of coagulase-negative staphylococci (CoNS) were recovered from 102 participants and identified into 14 species, with S. warneri being the most common (n = 52), followed by S. capitis (n = 42), S. saprophyticus (n = 20) and S. haemolyticus (n = 19). mecA was detected in S. saprophyticus, S. haemolyticus, and S. caprae, while arginine-catabolic mobile element (ACME) in only S. capitis and S. epidermidis. CONCLUSION: S. aureus was more prevalent in oral cavity than skin surface, belonging to three major STs, with CC1 being a dominant lineage. The prevalence of antimicrobial resistance was distinct depending on CoNS species.

Manuka honey as a non-antibiotic alternative against Staphylococcus spp. and their small colony variant (SCVs) phenotypes.

The antibiotic resistance (ABR) crisis is an urgent global health priority. Staphylococci are among the problematic bacteria contributing to this emergency owing to their recalcitrance to many clinically important antibiotics. Staphylococcal pathogenesis is further complicated by the presence of small colony variants (SCVs), a bacterial subpopulation displaying atypical characteristics including retarded growth, prolific biofilm formation, heightened antibiotic tolerance, and enhanced intracellular persistence. These capabilities severely impede current chemotherapeutics, resulting in chronic infections, poor patient outcomes, and significant economic burden. Tackling ABR requires alternative measures beyond the conventional options that have dominated treatment regimens over the past 8 decades. Non-antibiotic therapies are gaining interest in this arena, including the use of honey, which despite having ancient therapeutic roots has now been reimagined as an alternative treatment beyond just traditional topical use, to include the treatment of an array of difficult-to-treat staphylococcal infections. This literature review focused on Manuka honey (MH) and its efficacy as an anti-staphylococcal treatment. We summarized the studies that have used this product and the technologies employed to study the antibacterial mechanisms that render MH a suitable agent for the management of problematic staphylococcal infections, including those involving staphylococcal SCVs. We also discussed the status of staphylococcal resistance development to MH and other factors that may impact its efficacy as an alternative therapy to help combat ABR.

An update on non-aureus staphylococci and mammaliicocci in cow milk: unveiling the presence of Staphylococcus borealis and Staphylococcus rostri by MALDI-TOF MS.

Non-aureus staphylococci and mammaliicocci (NASM) are the microorganisms most frequently isolated from milk. Given their numerosity and complexity, MALDI-TOF MS is one of the preferred species identification approaches. Nevertheless, reference mass spectra for the novel species Staphylococcus borealis were included only recently in the Bruker Biotyper System (MBT) library, and other species of veterinary interest such as S. rostri are still absent. This work provides an updated picture of the NASM species found in milk, gained by retrospectively analyzing the data relating to 21,864 milk samples, of which 6,278 from clinical mastitis (CM), 4,039 from subclinical mastitis (SCM), and 11,547 from herd survey (HS), with a spectrum library including both species. As a result, S. borealis was the second most frequently isolated NASM (17.07%) after S. chromogenes (39.38%) in all sample types, with a slightly higher percentage in CM (21.84%), followed by SCM (17.65%), and HS (14.38%). S. rostri was also present in all sample types (3.34%), reaching 8.43% of all NASM in SCM and showing a significant association (p < 0.01) with this condition. Based on our findings, the presence of S. borealis and S. rostri in milk and their potential association with mastitis might have been overlooked, possibly due to the difficulties in differentiating these species from other closely related NASM. Our results indicate that S. borealis could be a more frequent contributor to bovine udder infections than previously thought and that S. rostri should also not be underestimated considering its significant association with SCM.

Complete genome sequence of three Staphylococcus epidermidis strains isolated from patients with skin diseases in Japan.

Staphylococcus epidermidis is a member of the human skin microbiota as a commensal organism but could be an important opportunistic pathogen for immunocompromised individuals. Here, we report the complete genome sequence of three S. epidermidis strains isolated from patients with skin diseases.

Association of coagulase-negative staphylococci with orthopedic infections detected by in-house multiplex real-time PCR.

Introduction: Clinical significance of coagulase-negative staphylococci (CoNS) has been gradually acknowledged in both healthcare and clinical research, but approaches for their precise discrimination at the species level remain scarce. The current study aimed to evaluate the association of CoNS with orthopedic infections, where accurate and prompt identification of etiology is crucial for appropriate diagnosis and treatment decision-making. Methods: A 16S rRNA-based quantitative PCR (qPCR) assay was developed for the detection of Staphylococcus genus and two panels of 3-plex qPCR assays for further differentiation of six CoNS species with remarkable clinical significance, including S. epidermidis, S. haemolyticus, S. simulans, S. hominis, S. capitis, and S. caprae. All the assays exhibited excellent analytical performance. ΔCq (quantification cycle) between 16S rRNA and CoNS species-specific targets was established to determine the primary CoNS. These methods were applied to detect CoNS in wound samples from orthopedic patients with and without infection. Results and discussion: Overall, CoNS were detected in 17.8% (21/118) of patients with clinically suspected infection and in 9.8% (12/123) of patients without any infection symptom (p < 0.05). Moreover, the association with infection was found to be bacterial quantity dependent. S. epidermidis was identified as the predominant species, followed by S. simulans, S. haemolyticus, and S. hominis. Male sex, open injury, trauma, and lower extremity were determined as risk factors for CoNS infections. CoNS-positive patients had significantly longer hospitalization duration (20 days (15, 33) versus 13 days (7, 22) for Staphylococcus-negative patients, p = 0.003), which could be a considerable burden for healthcare and individual patients. Considering the complex characteristics and devastating consequences of orthopedic infections, further expanding the detection scope for CoNS may be pursued to better understand the etiology of orthopedic infections and to improve therapeutic strategies.

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

BACKGROUND: Recently, 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. METHODS: The 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. RESULTS: All 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. CONCLUSION: The emergence of linezolid-resistant CoNS in the environment is concerning because it involves clonal dissemination and frequently coexists with various drug resistance mechanisms.

A capricious case of Staphylococcus caprae thoracic osteomyelitis.

Staphylococcus caprae (S. caprae) is a gram positive, coagulase-negative Staphylococci (CoNS) that occurs as a commensal pathogen on the human skin. It recently has been recognized in causing nosocomial infections involving the bloodstream, urinary tract, heart, bone, and joints, particularly in immunosuppressed patients or individuals with prosthetic devices. Previously, S. caprae was underreported as it was difficult to identify in the clinical microbiology laboratory; however, due to advances in molecular identification methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), more clinical cases are being identified in human isolates and appropriately treated. S. caprae osteoarticular infections are usually associated with polymicrobial infections and presence of orthopedic prostheses in immunocompromised adults. This pathogen has an even rarer presentation of bone and joint infections (BJIs) in immunocompetent individuals without orthopedic devices. Our case is of a 65-year-old immunocompetent male with diet-controlled diabetes mellitus type 2 and end-stage renal disease (ESRD) on hemodialysis who presented with worsening mid-thoracic pain after a ground-level fall and was diagnosed with biopsy-proven S. caprae thoracic discitis/osteomyelitis, associated with recurrent catheter-related bloodstream infection (CRBSI). It illustrates the importance of recognizing S. caprae as an emerging human pathogen, even in immunocompetent individuals without orthopedic hardware, requiring prompt targeted treatment of native BJIs to prevent unfavorable outcomes.

Rise in the Pathogenic Status of Coagulase-Negative Staphylococci Causing Bloodstream Infection.

BACKGROUND: Coagulase-negative staphylococci (CoNS) are one of the frequently isolated bacteria from blood cultures. Since they are part of the normal skin flora, they were previously considered contaminants. But now, they can be considered as established pathogens causing bloodstream infection (BSI). This study aims to estimate the prevalence of CoNS in BSI cases. METHODS: This study was conducted at the Microbiology Department, All India Institute of Medical Sciences (AIIMS), Raipur, India, for eight months (January 2022 to August 2022). Data were collected retrospectively from medical and laboratory records. Paired blood cultures from 5085 clinically suspected sepsis cases were subjected to aerobic culture for five days in the BacT ALERT 3D system. Pathogenicity was established after recovery of CoNS from paired blood cultures of symptomatic patients. RESULTS: CoNS were isolated from 2.35% of patients, the most common species being Staphylococcus haemolyticus (51.67%). About 90% of isolates were methicillin-resistant. All the isolates were susceptible to linezolid, teicoplanin, and vancomycin, except one isolate of S. haemolyticus which was intermediate to vancomycin. Minimum inhibitory concentration (MIC) 50 and MIC 90 for vancomycin were 1 ug/ml and 2 ug/ml, respectively.  Conclusion: Paired blood cultures are necessary to determine the pathogenicity of CoNS in BSI cases. A high prevalence of methicillin resistance, accompanied by high resistance rates to other non-beta lactam antibiotics, warrants the strict implementation of antimicrobial stewardship practices.

Value of 18 F-FDG PET/CT to Identify Occult Infection in Presumed Aseptic Pseudarthrosis after Spinal Fusion: Correlation with Intraoperative Cultures.

Objective Fluorine-18 fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) has gained attention as an emerging tool in case of suspicion of infection on spine, whether native or instrumented. However, the diagnostic performance of 18 F-FDG PET/CT in clinically occult low-grade surgical site infection (SSI) after spinal fusion, an important risk factor for pseudarthrosis, remains unknown. Methods We retrospectively identified all the presumed aseptic patients with pseudarthrosis confirmed by revision surgery who underwent preoperative 18 F-FDG PET/CT scans performed between April 2019 and November 2022. These patients were presumed aseptic because they did not have clinical signs or laboratory tests suggestive of SSI, preoperatively. The PET/CT images were analyzed in consensus by two nuclear medicine physicians blinded to the clinical, biological, and imaging information. Visual assessment of increased uptake around cage/intervertebral disk space (and/or hardware) higher than background recorded from the first normal adjacent vertebra was interpreted as positive. Image data were also quantitatively analyzed by the maximum standardized uptake value as an index of 18 F-FDG uptake, and the ratio between the uptake around cage/intervertebral disk space (and/or hardware) and background recorded from the first normal adjacent vertebra was calculated. The final diagnosis of infection was based on intraoperative cultures obtained during pseudarthrosis revision surgery. Results Thirty-six presumed aseptic patients with surgically confirmed pseudarthrosis after spinal fusion underwent preoperative 18 F-FDG PET/CT scans. Cultures of samples from revisions found that 20 patients (56%) were infected. The most frequent isolated bacterium was Cutibacterium acnes ( C. acnes ) in 15 patients (75%), followed by coagulase-negative staphylococci (CNS) in 7 patients (33%). Two patients had co-infections involving both C. acnes and CNS. Of the 36 PET/CT studied in this study, 12 scans were true-negative, 10 true-positive, 10 false-negative, and 4 false-positive. This resulted in sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 50%, 75%, 71%, 55%, and 61%, respectively. Conclusion In presumed aseptic pseudarthrosis after spinal fusion, 18 F-FDG PET/CT offers good specificity (75%) but low sensitivity (50%) to identify occult SSI. The high prevalence (56%) of SSI, mostly caused by C. acnes (75%), found in our presumed aseptic cohort of patients supports the utility of systematic intraoperative cultures in revision cases for pseudarthrosis.

Replacement of nitrates and nitrites in meat-derived foods through the utilization of coagulase-negative staphylococci: A review.

Nitrates and nitrites, which are synthetic additives, are traditionally used as curing agents in meat-based products. These synthetic additives are employed in the preparation of fermented meat foods to improve quality characteristics and microbiological safety, develop distinct flavours and red-colour stability, and counteract lipid oxidation. Nitrites also display significant bacteriostatic and bactericidal action against spoilage microorganisms and foodborne pathogens (such as Clostridium botulinum and Listeria monocytogenes). However, meat curing is currently under scrutiny because of its links to cardiovascular diseases and colorectal cancer. Based on the current literature, this review provides recent scientific evidence on the potential utilisation of coagulase-negative staphylococci (CNS) as nitrate and nitrite substitutes in meat-based foods. Indeed, CNS are reported to reproduce the characteristic red pigmentation and maintain the typical high-quality traits of cured-meats, thanks to their arginine degradation pathway, thus providing the nitrite-related desirable attributes in cured meat. The alternative strategy, still based on the NOS pathway, consisting of supplementing meat with arginine to release nitric oxide (NO) and obtain a meat characterised by the desired pinkish-red colour, is also reviewed. Exploiting NOS-positive CNS strains seems particularly challenging because of CNS technological adaptation and the oxygen dependency of the NOS reaction; however, this exploitation could represent a turning point in replacing nitrates and nitrites in meat foods.

A decade of neonatal sepsis in Stockholm, Sweden: Gram-positive pathogens were four times as common as Gram-negatives.

PURPOSE: To assess Gram-positive bacterial (GPB) bloodstream infection (BSI) in neonates, covering incidence, morbidity, mortality, antimicrobial resistance patterns and biomarkers in Region Stockholm, Sweden between 2006 and 2016. METHODS: A population-based retrospective epidemiological study including infants with GPB-BSI, admitted to the neonatal units at Karolinska University Hospital (KUH). Data were collected from patient records, the Swedish Neonatal Quality Register, the microbiological laboratory at KUH and the Swedish Public Health Agency. RESULTS: We identified 357 infants with GPB-BSI, representing an incidence of 1.47/1000 live births (LB). Group B streptococcus (GBS) was the most common pathogen causing BSI in full-term infants and early-onset sepsis (EOS) (0.20/1000 LB), while coagulase-negative staphylococci (CoNS) were predominant in infants born very preterm and in late-onset sepsis (LOS) (0.79/1000 LB). There were no fatal GBS BSI cases, but 10.2% developed meningitis. The GPB case fatality rate was 9.5% and the sepsis fatality rate 2.8%. In GPB-BSI, 1/10 did not have an elevated C-reactive protein level. Staphylococcus aureus (S. aureus) BSI increased during the study period, but no methicillin or vancomycin resistant strains were found. The antimicrobial resistance (AMR) rate was highest in CoNS isolates. CONCLUSION: GPB-BSI was four times more common than Gram-negative BSI in neonates but resulted in lower mortality rate. GBS was the most common pathogen in full-term infants and in EOS. CoNS was the most common pathogen in LOS and infants born very preterm, and the AMR rate was high in these isolates. The increasing trend of S. aureus BSI indicates a need of further investigation.

Contribution of staphylococcal virulence factors in the pathogenesis of thrombosis.

Staphylococci are responsible for many infections in humans, starting with skin and soft tissue infections and finishing with invasive diseases such as endocarditis, sepsis and pneumonia, which lead to high mortality. Patients with sepsis often demonstrate activated clotting pathways, decreased levels of anticoagulants, decreased fibrinolysis, activated endothelial surfaces and activated platelets. This results in disseminated intravascular coagulation and formation of a microthrombus, which can lead to a multiorgan failure. This review describes various staphylococcal virulence factors that contribute to vascular thrombosis, including deep vein thrombosis in infected patients. The article presents mechanisms of action of different factors released by bacteria in various host defense lines, which in turn can lead to formation of blood clots in the vessels.

Pathogenic potential of meat-borne coagulase negative staphylococci strains from slaughterhouse to fork.

This study aimed to determine the prevalence of coagulase-negative staphylococci (CoNS) in meat processing lines for their pathogenic potential associated with biofilm formation, staphylococcal toxin genes, and antibiotic resistance in obtained isolates. Out of 270 samples, 56 isolates were identified as staphylococcal with their species level, and their antimicrobial resistance profiles were also determined with the BD Phoenix™ system. Among these, CoNS were found in 32 isolates, including S. epidermidis (22%), S. warneri (22%), S. cohnii (9%), S. schleiferi (9%), S. capitis (6%), S. haemolyticus (6%), S. lugdunensis (6%), S. chromogenes (6%), S. kloosii (3%), S. sciuri (3%), S. lentus (3%), and S. caprae (3%). Biofilm formation was observed in 78.1% of CoNS isolates, with 56% being strong biofilm producers; and the frequency of the icaA, fnbA, and fnbB genes were 43.7% and 34.3%, and 9.3% in isolates, respectively. Twenty-five (78.1%) of these strains were resistant to at least one antimicrobial agent, 20 (80%) of which exhibited multidrug resistance (MDR). Regarding genotypic analyses, 15.6%, 22.2%, 87.5%, and 9% of isolates, were positive for blaZ, ermC, tetK, and aacA-aphD, respectively. In 8 (25%) of all isolates had one or more staphylococcal toxin genes: the sed gene was the most frequent (12.5%), followed by eta (9.3%), tst-1 (6.25%), and sea (3.1%). In conclusion, this study highlights meat; and meat products might be reservoirs for the biofilm-producing MDR-CoNS, which harbored several toxin genes. Hence, it should not be ignored that CoNS may be related to foodborne outbreaks.

Clinical Impact of Vancomycin MIC on Outcomes in Patients With Coagulase-negative Staphylococcal Bacteremia.

PURPOSE: Coagulase-negative staphylococci (CoNS) are Gram-positive organisms that are a known component of normal skin flora and the most common cause of nosocomial bacteremia. For CoNS species, the vancomycin MIC breakpoint for susceptibility set by the Clinical and Laboratory Standards Institute is ≤4 µg/mL. There has been published reports of vancomycin heteroresistance in CoNS with vancomycin MICs of 2 to 4 µg/mL. The aim of this retrospective cohort analysis was to assess the clinical impact of vancomycin MICs <2 µg/mL versus ≥2 µg/mL in adult patients with CoNS bloodstream infections. METHODS: Adult patients admitted to University Medical Center New Orleans with a blood culture positive for CoNS were assessed. The primary outcome was difference in 30-day mortality. Secondary outcomes were in-hospital, all-cause mortality; duration of bacteremia; hospital length of stay; and percentage of oxacillin-resistant CoNS. FINDINGS: There was no difference in mortality in the vancomycin MIC <2 µg/mL group versus the vancomycin MIC ≥2 µg/mL group at 30 days (15.4% vs 17.4%; P = 1). In-hospital, all-cause mortality was also not different between groups (11.5% vs 13%; P = 1). Hospital length of stay between groups was 28.2 days versus 21 days (P = 0.692). Median duration of bacteremia was 1 day in both groups (P = 0.975), and median scheduled duration of antibiotic therapy was 14.9 days and 19.5 days (P = 0.385). The source and mode of acquisition of CoNS were similar between groups. Of all CoNS isolates, 58.7% (44 of 75) were oxacillin resistant. Staphylococcus epidermidis was the most common CoNS species at 66.7% (50 of 75). Of all isolates, 30.7% (23 of 75) had a vancomycin MIC ≥2 µg/mL, and 87% (20 of 23) of these were S. epidermidis. There was a higher percentage of S. epidermidis in the vancomycin MIC ≥2 µg/mL group than in the MIC <2 µg/mL group (87% vs 57.7%; P = 0.012). CoNS with a vancomycin MIC ≥2 µg/mL were also more likely to be oxacillin resistant (78.3% vs 50%; P = 0.005). IMPLICATIONS: There was no difference in clinical outcomes in adult patients with a CoNS bloodstream infection with a vancomycin MIC <2 µg/mL versus ≥2 µg/mL. At present, vancomycin remains appropriate empiric therapy for CoNS bloodstream infection. Further research is needed to determine if there is a true clinical impact of a vancomycin MIC ≥2 µg/mL in CoNS infections.

Microbiological Quality and Safety of Fresh Rabbit Meat with Special Reference to Methicillin-Resistant S. aureus (MRSA) and ESBL-Producing E. coli.

The purpose of this investigation was to evaluate the microbial quality and safety of rabbit meat. A total of 49 rabbit meat samples were taken at the retail level. The mesophiles, staphylococci, Enterobacterales, and Pseudomonas spp. counts were 4.94 ± 1.08, 2.59 ± 0.70, 2.82 ± 0.67, and 3.23 ± 0.76 log CFU/g, respectively. Campylobacter spp. were not detected in any sample. Listeria monocytogenes was isolated from one sample (2.04%) at levels below 1.00 log CFU/g. Multi-resistant S aureus was found in seven samples (14.9%). Methicillin-resistant S. aureus, S. epidermidis, S. haemolyticus, M. caseolyticus, and M. sciuri were found in a sample each (10.20%), and all of them were multi-resistant. Multi-resistant ESBL-producing E. coli were detected in two samples from the same retailer (4.08%). The high resistance found in methicillin-resistant staphylococci and ESBL-producing E. coli is of particular concern, and suggests that special measures should be taken in rabbit meat.

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.

Wall teichoic acid substitution with glucose governs phage susceptibility of Staphylococcus epidermidis.

The species- and clone-specific susceptibility of Staphylococcus cells for bacteriophages is governed by the structures and glycosylation patterns of wall teichoic acid (WTA) glycopolymers. The glycosylation-dependent phage-WTA interactions in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) have remained unknown. We report a new S. epidermidis WTA glycosyltransferase TagE whose deletion confers resistance to siphoviruses such as ΦE72 but enables binding of otherwise unbound podoviruses. S. epidermidis glycerolphosphate WTA was found to be modified with glucose in a tagE-dependent manner. TagE is encoded together with the enzymes PgcA and GtaB providing uridine diphosphate-activated glucose. ΦE72 transduced several other CoNS species encoding TagE homologs, suggesting that WTA glycosylation via TagE is a frequent trait among CoNS that permits interspecies horizontal gene transfer. Our study unravels a crucial mechanism of phage-Staphylococcus interaction and horizontal gene transfer, and it will help in the design of anti-staphylococcal phage therapies.IMPORTANCEPhages are highly specific for certain bacterial hosts, and some can transduce DNA even across species boundaries. How phages recognize cognate host cells remains incompletely understood. Phages infecting members of the genus Staphylococcus bind to wall teichoic acid (WTA) glycopolymers with highly variable structures and glycosylation patterns. How WTA is glycosylated in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) species has remained unknown. We describe that S. epidermidis glycosylates its WTA backbone with glucose, and we identify a cluster of three genes responsible for glucose activation and transfer to WTA. Their inactivation strongly alters phage susceptibility patterns, yielding resistance to siphoviruses but susceptibility to podoviruses. Many different CoNS species with related glycosylation genes can exchange DNA via siphovirus ΦE72, suggesting that glucose-modified WTA is crucial for interspecies horizontal gene transfer. Our finding will help to develop antibacterial phage therapies and unravel routes of genetic exchange.

The effect of different antibiotic combinations in calcium sulfate cement on the growth of Cutibacterium acnes and Staphylococcus periprosthetic shoulder infection isolates.

BACKGROUND: Periprosthetic joint infections (PJI) of the shoulder are a devastating complication of shoulder arthroplasty and are commonly caused by Staphylococcus and Cutibacterium acnes. Absorbable calcium sulfate (CS) beads are sometimes used for delivering antibiotics in PJI. This study evaluates the in vitro effect of different combinations of gentamicin, vancomycin, and ertapenem in beads made from CS cement on the growth of C acnes and coagulase-negative Staphylococcus (CNS) strains. METHODS: Three strains of C acnes and 5 strains of CNS from clinically proven shoulder PJI were cultured and plated with CS beads containing combinations of vancomycin, gentamicin, and ertapenem. Plates with C acnes were incubated anaerobically while plates with Staphylococcus were incubated aerobically at 37 °C. Zones of inhibition were measured at intervals of 3 and 7 days using a modified Kirby Bauer technique, and beads were moved to plates containing freshly streaked bacteria every seventh day. This process was run in triplicate over the course of 56 days. Statistical analysis was conducted using SPSS v. 28 with repeated measures analysis of variance (ANOVA) and pairwise comparisons with Tukey correction. RESULTS: In experiments with C acnes, beads containing ertapenem + vancomycin and vancomycin alone formed the largest zones of inhibition over time (P < .001). In experiments with Staphylococcus, beads containing vancomycin alone formed the largest zones of inhibition over time for all 5 strains (P < .001). Zones of inhibition were 1.4x larger for C acnes than for Staphylococcus with beads containing vancomycin alone. For both C acnes and Staphylococcus, beads containing ertapenem had the strongest initial effect, preventing all bacterial growth in C acnes and almost all growth for Staphylococcus during the first week but dropping substantially by the second week. Beads containing gentamicin alone consistently created smaller zones of inhibition than beads containing vancomycin alone, with vancomycin producing zones 5.3x larger than gentamicin in C acnes and 1.3x larger in Staphylococcus (P < .001). DISCUSSION: These data suggest that for both C acnes and Staphylococcal species, CS beads impregnated with vancomycin were most effective at producing a robust antibiotic effect. Additionally, ertapenem may be a viable supplement in order to create a more potent initial antibiotic effect but is not as effective as vancomycin when used alone. Gentamicin alone was not effective in maintaining consistent and long-term antibiotic effects. These results indicate that amongst the antibiotics currently commercially available to be used with CS, vancomycin is consistently superior to gentamicin in the setting of C. acnes and CNS.

Staphylococcus capitis Bloodstream Isolates: Investigation of Clonal Relationship, Resistance Profile, Virulence and Biofilm Formation.

Staphylococcus capitis has been recognized as a relevant opportunistic pathogen, particularly its persistence in neonatal ICUs around the world. Therefore, the aim of this study was to describe the epidemiological profile of clinical isolates of S. capitis and to characterize the factors involved in the persistence and pathogenesis of these strains isolated from blood cultures collected in a hospital in the interior of the state of São Paulo, Brazil. A total of 141 S. capitis strains were submitted to detection of the mecA gene and SCCmec typing by multiplex PCR. Genes involved in biofilm production and genes encoding enterotoxins and hemolysins were detected by conventional PCR. Biofilm formation was evaluated by the polystyrene plate adherence test and phenotypic resistance was investigated by the disk diffusion method. Finally, pulsed-field gel electrophoresis (PFGE) was used to analyze the clonal relationship between isolates. The mecA gene was detected in 99 (70.2%) isolates, with this percentage reaching 100% in the neonatal ICU. SCCmec type III was the most prevalent type, detected in 31 (31.3%) isolates and co-occurrence of SCCmec was also observed. In vitro biofilm formation was detected in 46 (32.6%) isolates but was not correlated with the presence of the ica operon genes. Furthermore, biofilm production in ICU isolates was favored by hyperosmotic conditions, which are common in ICUs because of the frequent parenteral nutrition. Analysis of the clonal relationship between the isolates investigated in the present study confirms a homogeneous profile of S. capitis and the persistence of clones that are prevalent in the neonatal ICU and disseminated across the hospital. This study highlights the adaptation of isolates to specific hospital environments and their high clonality.