Bacteria colonization and gene expression related to immune function in colon mucosa is associated with growth in neonatal calves regardless of live yeast supplementation

Background As Holstein calves are susceptible to gastrointestinal disorders during the first week of life,understanding how intestinal immune function develops in neonatal calves is important to promote better intestinal health.Feeding probiotics in early life may contribute to host intestinal health by facilitating beneficial bacteria colonization and developing intestinal immune function.The objective of this study was to characterize the impact of early life yeast supplementation and growth on colon mucosa-attached bacteria and host immune function.Results Twenty Holstein bull calves received no supplementation(CON)or Saccharomyces cerevisiae boulardii(SCB)from birth to 5 d of life.Colon tissue biopsies were taken within 2 h of life(D0)before the first colostrum feeding and 3 h after the morning feeding at d 5 of age(D5)to analyze mucosa-attached bacteria and colon transcriptome.Metagenome sequencing showed that there was no difference inαandβdiversity of mucosa-attached bacteria between day and treatment,but bacteria related to diarrhea were more abundant in the colon mucosa on D0 compared to D5.In addition,q PCR indicated that the absolute abundance of Escherichia coli(E.coli)decreased in the colon mucosa on D5 compared to D0;however,that of Bifidobacterium,Lactobacillus,and Faecalibacterium prausnitzii,which could competitively exclude E.coli,increased in the colon mucosa on D5 compared to D0.RNA-sequencing showed that there were no differentially expressed genes between CON and SCB,but suggested that pathways related to viral infection such as“Interferon Signaling”were activated in the colon mucosa of D5 compared to D0.Conclusions Growth affected mucosa-attached bacteria and host immune function in the colon mucosa during the first 5 d of life in dairy calves independently of SCB supplementation.During early life,opportunistic pathogens may decrease due to intestinal environmental changes by beneficial bacteria and/or host immune function.Predicted activation of immune function-related pathways may be the result of host immune function development or suggest other antigens in the intestine during early life.Further studies focusing on the other antigens and host immune function in the colon mucosa are required to better understand intestinal immune function development.

Adding vortexing to the Maki technique provides no benefit for the diagnosis of catheter colonization or catheter-related bacteremia

BACKGROUND A previous study compared vortexing and Maki techniques for the diagnosis of catheter-related bloodstream infection(CRBSI),and concluded that vortexing was not superior to Maki method.AIM To determine whether the combined use of vortexing and Maki techniques provides profitability versus the Maki technique for the diagnosis of catheter tip colonization(CTC)and CRBSI.METHODS Observational and prospective study carried out in an Intensive Care Unit.Patients with suspected catheter-related infection(CRI)and with one central venous catheter for at least 7 days were included.The area under the curve(AUC)of the Maki technique,the vortexing technique and the combination of both techniques for the diagnosis of CTC and CRBSI were compared.RESULTS We included 136 episodes of suspected CRI.We found 21 cases of CTC of which 10 were also CRBSI cases.Of the 21 CTC episodes,18(85.7%)were diagnosed by Maki technique and vortexing technique,3(14.3%)only by the technique of Maki,and none only by technique of vortexing.Of the 10 CRBSI episodes,9(90.0%)were diagnosed by the techniques of Maki and vortexing,1(10.0%)was diagnosed only by the technique of Maki,and none only by the technique of vortexing.We no found differences in the comparison of AUC between the technique of Maki and the combination of Maki and vortexing techniques for the diagnosis of CTC(P=0.99)and CRBSI(P=0.99).CONCLUSION The novel finding of our study was that the combined use of vortexing and Maki techniques did not provide profitability to the technique of Maki alone to CRBSI diagnosis of.

Epidemiology of carbapenem-resistant Acinetobacter baumannii colonization in neonatal intensive care units:A systematic review and meta-analysis

BACKGROUND The rising prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)in neonatal intensive care units(NICUs)represents an escalating challenge in healthcare settings,particularly in managing hospital-acquired infections(HAIs).Studies across various World Health Organization regions have documented a significant incidence of CRAB-related HAIs,with rates as high as 41.7 cases per 1000 patients in ICUs,accounting for 13.6%of all HAIs.These infections pose a doubled mortality risk compared to infections with carbapenem-susceptible Acinetobacter baumannii.A particularly concerning aspect of CRAB colonization is its asymptomatic nature,enabling its transmission through healthcare workers(HCWs)or the NICU environment to vulnerable neonates with developing immune systems.AIM To explore the prevalence of CRAB colonization in NICUs,focusing on neonates,healthcare workers,and the environmental samples,to enhance epidemiological understanding and inform targeted interventions.METHODS We conducted according to PRISMA 2020 checklist guidelines,a comprehensive literature search across multiple databases including MEDLINE(Ovid),EMBASE(Ovid),Global Health(Ovid),Web of Science,and Global Index Me-dicus.Studies were selected based on predetermined criteria,primarily involving neonates,HCWs,and environmental swabs,using culture or molecular methods to detect CRAB colonization.We excluded studies that did not specifically focus on NICUs,were duplicates,or lacked necessary data.The study selection and quality assessment were conducted independently by two reviewers.Data extraction involved collecting comprehensive details about each study.Our statistical analysis used a random-effects model to calculate the pooled prevalence and confidence intervals,stratifying results by regional location.We assessed study heterogeneity using Cochran's Q statistic and I²statistic,with regression tests employed to evaluate potential publication bias.RESULTS We analyzed 737 records from five databases,ultimately including 13 studies from ten countries.For neonates,the pooled prevalence was 4.8%(95%CI:1.1%to 10.5%)with the highest rates observed in South-East Asia(10.5%;95%CI:2.4%to 23.3%).Among HCWs,a single Indian study reported a 3.3%prevalence.Environmental samples showed a prevalence of 2.3%(95%CI:0%to 9.3%),with the highest rates in South-East Asia(10%;95%CI:4.2%to 17.7%).Significant heterogeneity was found across studies,and no publication bias was detected.CONCLUSION This systematic review highlights a significant prevalence of CRAB colonization in neonates across various regions,particularly in South-East Asia,contrasting with lower rates in high-income countries.The study reveals a gap in research on HCWs colonization,with only a single study from India reporting moderate prevalence.Environmental samples indicate moderate levels of CRAB contamination,again higher in South-East Asia.These findings underscore the need for more extensive and focused research on CRAB colonization in NICUs,including exploring the roles of HCWs and the environment in transmission,understanding antimicrobial resistance patterns,and developing effective prevention measures.

Colonization Pattern of Azospirillum brasilense Yu62 on Maize Roots

Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.

Factors that mediate colonization of the human stomach by Helicobacter pylori

Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.

Maternal imprinting of the neonatal microbiota colonization in intrauterine growth restricted piglets:a review

Early colonization of intestinal microbiota during the neonatal stage plays an important role on the development of intestinal immune system and nutrients absorption of the host.Compared to the normal birth weight(NBW)piglets,intrauterine growth restricted(IUGR)piglets have a different intestinal microbiota during their early life,which is related to maternal imprinting on intestinal microbial succession during gestation,at birth and via suckling.Imbalanced allocation of limited nutrients among fetuses during gestation could be one of the main causes for impaired intestinal development and microbiota colonization in neonatal IUGR piglets.In this review,we summarized the potential impact of maternal imprinting on the colonization of the intestinal microbiota in IUGR piglets,including maternal undernutrition,imbalanced allocation of nutrients among fetuses,as well as vertical microbial transmission from mother to offspring during gestation and lactation.At the same time,we give information about the current maternal nutritional strategies(mainly breastfeeding,probiotics and prebiotics)to help colonization of the advantageous intestinal microbiota for IUGR piglets.

Natural Colonization of Rice by Arbuscular Mycorrhizal Fungi in Different Production Areas

Interactions between plants and soil microorganisms can influence the other interactions in which plants participate, including interactions with herbivores. Many fungi, including arbuscular mycorrhizal fungi(AMF), form symbiotic relationships with the roots they inhabit, and potentially alter defense against pests. The objective of this study was to document the extent of root colonization by AMF on non-flooded rice plants grown under conditions typical of commercial fields. We hypothesized that AMF naturally colonized rice plants in different rice producing field locations. Rice plant samples were collected from areas across the southern United States, including Texas, Mississippi, Arkansas and two research stations in Louisiana. We quantified the amount of AMF colonization in insecticide-free rice plants over three consecutive years(2014–2016). The results revealed natural colonization of AMF in all rice producing areas. In all the three years of survey, rice-AMF associations were the greatest in Arkansas followed by Mississippi and Texas. This research will help draw attention to natural colonization of AMF in rice producing areas that can impact future rice research and production by facilitating agricultural exploitation of the symbiosis.

Non-thermal Plasma Suppresses Bacterial Colonization on Skin Wound and Promotes Wound Healing in Mice

The present study evaluated the effect of non-thermal plasma on skin wound healing in BalB/c mice.Two 6-mm wounds along the both sides of the spine were created on the back of each mouse（n=80） by using a punch biopsy.The mice were assigned randomly into two groups,with 40 animals in each group：a non-thermal plasma group in which the mice were treated with the non-thermal plasma;a control group in which the mice were left to heal naturally.Wound healing was evaluated on postoperative days（POD） 4,7,10 and 14（n=5 per group in each POD） by percentage of wound closure.The mice was euthanized on POD 1,4,7,10,14,21,28 and 35（n=1 in each POD）.The wounds were removed,routinely fixed,paraffin-embedded,sectioned and HE-stained.A modified scoring system was used to evaluate the wounds.The results showed that acute inflammation peaked on POD 4 in non-thermal plasma group,earlier than in control group in which acute inflammation reached a peak on POD 7,and the acute inflammation scores were much lower in non-thermal group than in control group on POD 7（P0.05）.The amount of granular tissue was greater on POD 4 and 7 in non-thermal group than in control group（P0.05）.The re-epithelialization score and the neovasularization score were increased significantly in non-thermal group when compared with control group on POD 7 and 10（P0.05 for all）.The count of bacterial colonies was 103 CFU/mL on POD 4 and 20 CFU/mL on POD 7,significantly lower than that in control group（109 CFU/mL on POD 4 and 1012 CFU/mL on the POD 7）（P0.05）.It was suggested that the non-thermal plasma facilitates the wound healing by suppressing bacterial colo-nization.

Colonization of Rice Roots by a Green Fluorescent Protein-Tagged Isolate of Ustilaginoidea virens

The fungus U. virens is the causal agent of rice false smut disease. The green fluorescent protein (GFP) was used to mark this fungus in order to visualize and analyze the colonization and infection processes in vivo. Using epifluorescence microscopy colonization and infection on rice roots were visualized in vivo. After inoculation for 2 to 15 d, it was observed that the conidia and their germ-tubes had penetrated into epidermis of young roots. The hyphae were found inside the root xylem 18 d after inoculation. Generally, the transformed fungus colonized the rhizosphere, the cortex as well as the vascular tissues with symptoms of root necrosis observed. The results of this work show that U. virens colonize not only rice panicles but also the roots.

Bacterial colonization and intestinal mucosal barrier development

The intestinal tract is colonized soon after birth with a variety of ingested environmental and maternal microflora. This process is influenced by many factors including mode of delivery, diet, environment, and the use of antibiotics. Normal intestinal microflora provides protection against infection, ensures tolerance to foods, and contributes to nutrient digestion and energy harvest. In addition, enteral feeding and colonization with the normal commensal flora are necessary for the maintenance of intestinal barrier function and play a vital role in the regulation of intestinal barrier function. Intestinal commensal microorganisms also provide signals that foster normal immune system development and influence the ensuing immune responses. There is increasingly recognition that alterations of the microbial gut flora and associated changes in intestinal barrier function may be related to certain diseases of the gastrointestinal tract. This review summarizes recent advances in understanding the complex ecosystem of intestinal microbiota and its role in regulating intestinal barrier function and a few common pediatric diseases. Disruption in the establishment of a stable normal gut microflora may contribute to the pathogenesis of diseases including inflammatory bowel disease, nosocomial infection, and neonatal necrotizing enterocolitis.

Bacterial Colonization of the Equine Gut;Comparison of Mare and Foal Pairs by PCR-DGGE

Horses, like all animals, are born without the symbiotic microbes that occupy the gastrointestinal tracts of mature animals. As grazing animals, horses rely on these microbes to fully utilize the grasses and other cellulosic feeds that they consume. Thus, colonization of the foal's gastrointestinal tract must occur between birth and weaning. The feces of nine mare and foal pairs were sampled from the day of parturition until 12 weeks of age, and the samples were analyzed by polymerase chain reaction amplification of the bacterial 16S rRNA gene and denaturing gradient gel electrophoresis (PCR-DGGE). The gels from feces of day (d) 0 foals had no or very few ( x = 3, n = 6) bands, which indicates that species richness was low. The number of bands increased during the first 4 days of life, and by d 14 the foals and mares had similar numbers of bands ( x = 28, n = 23). Some bands were present in young foals, but not in mares or in foals on d 42 or d 84, which indicated succession of bacterial species. When the PCR-DGGE profiles were compared with Dice's algorithm, all mare-foal pairwise similarities on d 14 and later were as great as the pairwise similarities between mares. These results are consistent with the idea that foals are born with a sterile gut, colonization proceeds rapidly, and a mature microbial community is present in the first few weeks of life.

Celecoxib inhibits Helicobacter pylori colonization-related factors

AIM:To investigate the effect of celecoxib,a selective COX-2 inhibitor,on Helicobacter pylori(H.pylori) colonization-related factors and its mechanism.METHODS:After co-incubation with celecoxib,morphology of H.pylori strain 26695 was observed under a transmission electron microscope.Flagella motility was assessed by stab agar motility test.Adherence of H.pylori to AGS cells was determined by enzyme linked immunosorbent assay.Levels of mRNA expression in flagellar genes(flaA,flaB),urease genes(ureA,ureB)and adhesin genes(babA,sabA,alpA,alpB,hpaA,hopZ)were measured by real-time polymerase chain reaction.RESULTS:Separation and non-integrity of bacterial cell wall,rarefaction and asymmetry of cytoplasm,and even lysis of H.pylori were observed in the presence of celecoxib.When H.pylori strains were incubated in the presence of celecoxib,their flagellar motility and adherence to AGS cells were inhibited.The expression of ureA,ureB,babA,sabA,alpA,alpB,hpaA,hopZ was up-regulated while the expression of flaA,flaB was down-regulated in the presence of celecoxib.CONCLUSION:Celecoxib inhibits flagellar motility and adherence of H.pylori to AGS cells,and destructs their normal structure in vitro.

Colonization and development of the gut microbiome in calves

Colonization and development of the gut microbiome are crucial for the growth and health of calves.In this review,we summarized the colonization,beneficial nutrition,immune function of gut microbiota,function of the gut barrier,and the evolution of core microbiota in the gut of calves of different ages.Homeostasis of gut microbiome is beneficial for nutritional and immune system development of calves.Disruption of the gut microbiome leads to digestive diseases in calves,such as diarrhea and intestinal inflammation.Microbiota already exists in the gut of calf fetuses,and the colonization of microbiota continues to change dynamically under the influence of various factors,which include probiotics,diet,age,and genotype.Colonization depends on the interaction between the gut microbiota and the immune system of calves.The abundance and diversity of these commensal microbiota stabilize and play a critical role in the health of calves.

Colonization of Bacillus cereus NJSZ-13,a species with nematicidal activity in Masson pine(Pinus massoniana Lamb.)

Bacillus cereus NJSZ-13,an endophytic bacterium with nematicidal activity,was isolated from stems of healthy Pinus elliottii Engelm.Colonization of P.massoniana Lamb.by endophytic B.cereus was studied using scanning electron microscopy and confocal laser scanning microscopy.After the plasmid p GFP78 containing the green fluorescent protein(GFP)gene was transformed into the NJSZ-13 strain,the NJSZ-13:gfp showed the same nematicidal activity and growth curve as the wild-type strain,and the plasmid p GFP78 was stably maintained in strain NJSZ-13 for at least 96 h of bacterial cultivation on medium without antibiotics.After inoculation into Masson pine roots,colonization of the NJSZ-13:gfp strain in plant roots and stems was visualized using confocal laser scanning and the strain was enumerated in inoculated roots and stems.These results suggest that NJSZ-13:gfp is an efficient colonizer of Masson pine and can transfer vertically from roots to stems.

Confocal Laser Scanning Microscope Evaluation of Early Bacterial Colonization on Zirconium Oxide and Titanium Surfaces:An in vivo Study

To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.

Characterization of flgK gene and FlgK protein required for H pylori Colonization-from cloning to clinical relevance

AIM： To characterize the role of flgK and its protein product in Hpylori colonization. METHODS： The PCR cloning method identified the flgK gene. An isogenic flgK mutant was constructed by gene replacement and confirmed by Southern blot analysis and PCR analysis. The recombinant FlgK protein （r-FlgK） was purified. Electron microscopy （EM） was applied to demonstrate the flagella of H pylori. An in vitro motility test was assessed in semisolid medium. The densities of H pylori colonization with either the wild-type strain or its flgK mutant were compared among BALB/c mice with or without pre-immunization with r-FlgK. The serological responses to r-FlgK were analyzed for 70 clinical patients with different densities of H pylori colonization. RESULTS： From a duodenal ulcer strain, the flgK gene was cloned and it contained 1821 bp, with a 95.7% identity to the published sequences. No flagella were observed under EM for the mutant strain, which had a loss of motility. Hpylori density was lower in the BALB/c mice inoculated by the mutant or with pre-immunization with r-FlgK compared to unimmunized mice or mice inoculated by the wild-type strain （P 〈 0.05）. In the H pylori-infected patients, the serological responses to r-FlgK were uniformly low in titer.CONCLUSION： FlgK encoded by flgK is important for flagella formation and H pylori motility. Deficiency in FlgK or an enhanced serological response to r-FlgK can interfere with Hpylori colonization. FlgK of Hpylori could be a novel target for vaccination.

Colonization and Probiotic Effect of Metschnikowia sp. C14 in the Intestine of Juvenile Sea Cucumber, Apostichopus japonicus

Viable cell count was used to determine whether Metschnikowia sp.C14 can colonize the intestine of juvenile sea cucumber Apostichopus japonicus.Sea cucumber individuals were divided into two groups,which were fed the control diet for 38 days or the C14-supplemented diet at 105 cells g−1 diet for 28 days,then the control diet from day 29 to day 38.The number of C14 cells in the intestine of sea cucumber fed the C14-supplemented diet significantly increased from day 7 to day 28,and decreased from day 29 to day 38.Sea cucumber fed with the diet containing C14 showed a significant increase in trypsin activity and lipase activity from day 21 to day 33 compared with the control.Feeding C14 significantly improved the phagocytic activity and respiratory burst in coelomocytes from day 21 to day 35 and from day 14 to day 38,respectively.In addition,there was an obvious enhancement in lysozyme activity(from day 21 to day 38 or day 33),phenoloxidase activity(from day 21 to day 28)and total nitric oxide synthase activity(from day 14 to day 38)in coelomic fluid supernatant and/or coelomocyte cell lysate supernatant compared with the control.There were significant positive correlations between the number of C14 cells colonizing the intestine and trypsin activity of the intestine,lysozyme activity of the coelomic fluid supernatant and coelomocyte lysate supernatant from sea cucumber.These data suggested that the number of C14 cells should be maintained at 105 cfu(colony-forming units)g−1 intestine material for the maximum benefit.

Colonization Ability of Bacillus subtilis HAS in Sugarcane

Bacillus subtilis HAS had good control effects on sugarcane smut in the field. Colonization dynamics of B. subtilis HAS were studied through biotics marker and pot culture, to understand the bio-control mechanism of the strain and provide experimental basis for commercialization. The results showed that B.subtilis HAS had strong colonization ability, which could be colonized in sugarcane root, stem, leaf and rhizosphere for long time, but the colonization levels were different. The colonization density of B.sutili HAS remained 103 CFU/g soil in the rhizosphere and 102 CFU/g （fresh weight） in the root after inoculation of 60 d. The colonization in the rhizosphere decreased first, then increased and decreased again, and finally stabilized. The colonization in the root first increased then decreased. Meantime, colonization status in stems and leaves showed that the colonization density in stems and leaves was 10 CFU/g （fresh weight）, indicating that the colonization level was not high in stem and leaf.

Biofilm Development, Plant Growth Promoting Traits and Rhizosphere Colonization by <i>Pseudomonas entomophila</i>FAP1: A Promising PGPR

Among the diverse soil bacteria, plant growth promoting rhizobacteria (PGPR) mark an important role in enhancing plant growth through a range of beneficial functions. This is mainly achieved by effective rhizosphere colonization by PGPR. Biofilm development by PGPR is considered as a survival strategy over the planktonic mode of growth under stress and natural conditions. Since the performance of microbial inoculants under field conditions is not always consistent due to various biotic and abiotic factors affecting survival, colonization and functions. Therefore, the rhizobacteria with efficient colonization ability and exhibiting multiple PGP traits are expected to perform better. We hypothesized that the biofilm forming ability of PGPR on plant root will be an added advantage to rhizosphere colonization. Therefore, we have selected a promising isolate of PGPR through random screening programme from rhizoplane of wheat (Triticum aestivum). The selection was based on biofilm development ability, multifarious PGP activities (production of indole acetic acid, sidero-phore, phosphate solubilization, hydrogen cyanide, ammonia production and biocontrol activity) and tolerance to salinity and heavy metals. The selected isolate was identified by 16 s rRNA partial gene sequencing as Pseudomonas entomophila-FAP1. The strain FAP1 formed strong biofilm in microtitre plate, glass surface as well as on the roots of wheat seedlings. Biofilm forming capacity of the FAP1 was characterized by scanning electron microscopy and confocal laser scanning microscopy. FAP1 exhibited biofilm-related traits such as the production of exopolysaccharides, EPS (1501.33 ± 1.08 μg ml-1), alginate (212.81 ± 1.09 μg ml-1), swarming motility (22 ± 1.36 mm), swimming motility (31 ± 2.12 mm) and cell surface hydrophobicity (63%). Rhizosphere colonization by FAP1 was found 7.5 Log CFU g-1 of soil comparable with rhizoplane colonization (7.2 Log CFU g-1 of root). Therefore, biofilm formation on plant roots by promising PGPR may be included as an additional criterion to select a better rhizosphere colonizer. Further, study with mutant deficient in biofilm should be developed for comparative study to explore the exact contribution of biofilm in root colonization under natural soil-plant system.

The Prevalence of Methicillin-Resistant Staphylococcus aureus Colonization in Patients with Complicated Skin and Skin Structure Infections after Treatment with Linezolid or Vancomycin

Background: Complicated skin and skin structure infections (cSSSIs) due to Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), are associated with significant morbidity. Re-ducing MRSA carriage has been a focus of infection control interventions. The prevalence of MRSA colonization after successful treatment of a MRSA cSSSI is unknown. Methods: Secondary analysis of a randomized controlled trial comparing linezolid and vancomycin for the treatment of MRSA cSSSI. Adult patients that had a colonization culture, confirmed MRSA cSSSI, received at least one dose of study treatment, and had an outcome recorded at end of study. Patient, clinical characteristics and prevalence of colonization were compared by treatment regimens. A multivariate regression model identified predictors of MRSA colonization at EOS. Results: There were 456 patients evaluated. The prevalence of MRSA colonization was higher for vancomycin treated patients compared to linezolid treated patients at end of treatment (EOT) (28% vs. 5%, p < 0.001) and EOS (34% vs. 22%, p < 0.01). Independent predictors of colonization at EOS after treatment for a MRSA cSSSI included diagnosis, primarily driven by abscess, black race, treatment with vancomycin, MRSA mixed infection and male gender. Conclusion: Patients treated with linezolid for a cSSSI had less MRSA colonization at EOT and EOS compared to those treated with vancomycin. Multiple independent predictors of MRSA colonization were identified. Additional studies evaluating the relationship of MRSA colonization after treatment of cSSSI are needed.