Detection of multidrug-resistant bacteria in the nasal cavities and evaluation of sinus disorders in patients undergoing Le Fort I osteotomy

INTRODUCTION

Orthognathic surgery can lead to sinus alterations, including sinusitis, attributed to the exposure of maxillary sinuses during Le Fort I osteotomy. Furthermore, being a hospital-based procedure, there is potential risk of complications arising from bacteria prevalent in such environments. This study evaluated maxillary sinusitis occurrence and the presence of multidrug-resistant bacteria in the nasal cavity before and after orthognathic surgery.

METHODS

Ten patients with dentofacial deformities underwent Le Fort I osteotomy. Clinical evaluations using SNOT-22 questionnaire were performed, and nasal cavity samples were collected pre-surgery and 3-6 months post-surgery to quantify total mesophilic bacteria and detect Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae. Cone Beam Computed Tomography (CBCT) was performed pre- and post-operatively, and the results were evaluated using the Lund-Mackay system. This study was registered and approved by the Research Ethics Committee of PUCRS (No. 4.683.066).

RESULTS

The evaluation of SNOT-22 revealed that five patients showed an improvement in symptoms, while two remained in the same range of interpretation. One patient developed post-operative maxillary sinusitis, which was not detected at the time of evaluation by SNOT-22 or CBCT. CBCT showed a worsening sinus condition in three patients, two of whom had a significant increase in total bacteria count in their nasal cavities. The Brodsky scale was used to assess hypertrophy in palatine tonsils, where 60% of the subjects had grade 1 tonsils, 20% had grade 2 and 20% had grade 3. None of the patients had grade 4 tonsils, which would indicate more than 75% obstruction. Two patients harboured S. aureus and K. pneumoniae in their nasal cavities. Notably, K. pneumoniae, which was multidrug-resistant, was present in the nasal cavity of patients even before surgery, but this did not result in maxillary sinusitis, likely due to the patients' young and healthy condition.

CONCLUSION

There was an improvement in signs and symptoms of maxillary sinusitis and quality of life in most patients after orthognathic surgery. However, some patients may still harbour multidrug-resistant bacteria, even if they are asymptomatic. Therefore, a thorough pre-operative assessment is essential to avoid difficult-to-treat post-operative complications.

Human nasal microbiota shifts in healthy and chronic respiratory disease conditions

BACKGROUND

An increasing number of studies investigate various human microbiotas and their roles in the development of diseases, maintenance of health states, and balanced signaling towards the brain. Current data demonstrate that the nasal microbiota contains a unique and highly variable array of commensal bacteria and opportunistic pathogens. However, we need to understand how to harness current knowledge, enrich nasal microbiota with beneficial microorganisms, and prevent pathogenic developments.

RESULTS

In this study, we have obtained nasal, nasopharyngeal, and bronchoalveolar lavage fluid samples from healthy volunteers and patients suffering from chronic respiratory tract diseases for full-length 16 S rRNA sequencing analysis using Oxford Nanopore Technologies. Demographic and clinical data were collected simultaneously. The microbiome analysis of 97 people from Lithuania suffering from chronic inflammatory respiratory tract disease and healthy volunteers revealed that the human nasal microbiome represents the microbiome of the upper airways well.

CONCLUSIONS

The nasal microbiota of patients was enriched with opportunistic pathogens, which could be used as indicators of respiratory tract conditions. In addition, we observed that a healthy human nasal microbiome contained several plant- and bee-associated species, suggesting the possibility of enriching human nasal microbiota via such exposures when needed. These candidate probiotics should be investigated for their modulating effects on airway and lung epithelia, immunogenic properties, neurotransmitter content, and roles in maintaining respiratory health and nose-brain interrelationships.

Gut-associated microbes are present and active in the pig nasal cavity

The nasal microbiota is a key contributor to animal health, and characterizing the nasal microbiota composition is an important step towards elucidating the role of its different members. Efforts to characterize the nasal microbiota composition of domestic pigs and other farm animals frequently report the presence of bacteria that are typically found in the gut, including many anaerobes from the Bacteroidales and Clostridiales orders. However, the in vivo role of these gut-microbiota associated taxa is currently unclear. Here, we tackled this issue by examining the prevalence, origin, and activity of these taxa in the nasal microbiota of piglets. First, analysis of the nasal microbiota of farm piglets sampled in this study, as well as various publicly available data sets, revealed that gut-microbiota associated taxa indeed constitute a substantial fraction of the pig nasal microbiota that is highly variable across individual animals. Second, comparison of herd-matched nasal and rectal samples at amplicon sequencing variant (ASV) level showed that these taxa are largely shared in the nasal and rectal microbiota, suggesting a common origin driven presumably by the transfer of fecal matter. Third, surgical sampling of the inner nasal tract showed that gut-microbiota associated taxa are found throughout the nasal cavity, indicating that these taxa do not stem from contaminations introduced during sampling with conventional nasal swabs. Finally, analysis of cDNA from the 16S rRNA gene in these nasal samples indicated that gut-microbiota associated taxa are indeed active in the pig nasal cavity. This study shows that gut-microbiota associated taxa are not only present, but also active, in the nasal cavity of domestic pigs, and paves the way for future efforts to elucidate the function of these taxa within the nasal microbiota.

Proteomic scrutiny of nasal microbiomes: implications for the clinic

INTRODUCTION

The nasal cavity is the initial site of the human respiratory tract and is one of the habitats where microorganisms colonize. The findings from a growing number of studies have shown that the nasal microbiome is an important factor for human disease and health. 16S rRNA sequencing and metagenomic next-generation sequencing (mNGS) are the most commonly used means of microbiome evaluation. Among them, 16S rRNA sequencing is the primary method used in previous studies of nasal microbiomes. However, neither 16S rRNA sequencing nor mNGS can be used to analyze the genes specifically expressed by nasal microorganisms and their functions. This problem can be addressed by proteomic analysis of the nasal microbiome.

AREAS COVERED

In this review, we summarize current advances in research on the nasal microbiome, introduce the methods for proteomic evaluation of the nasal microbiome, and focus on the important roles of proteomic evaluation of the nasal microbiome in the diagnosis and treatment of related diseases.

EXPERT OPINION

The detection method for microbiome-expressed proteins is known as metaproteomics. Metaproteomic analysis can help us dig deeper into the nasal microbiomes and provide new targets and ideas for clinical diagnosis and treatment of many nasal dysbiosis-related diseases.

Prolonged mask wearing changed nasal microbial characterization of young adults during the COVID-19 pandemic in Shanghai, China

Background

Face masks have become a common sight during the Coronavirus Disease 2019 (COVID-19) pandemic in many countries. However, the impact of prolonged face mask wearing on nasal microbiota of healthy people is not fully understood.

Methods

In this study, we compared the nasal microbiota of 82 young adults who wore face masks for an extended period of time to 172 mask-free peers from the same school recruited before the COVID-19 pandemic via 16S ribosomal RNA gene sequencing. Diversity, composition, and function of nasal microbiota between the two groups were analyzed. Prevalence of commensal bacteria colonized in the nasal cavity was determined by culture-based analysis.

Results

We observed that prolonged face mask wearers had significantly different nasal microbial characterization and metabolic function compared to mask-free controls from 2018. Specifically, the nasal microbiota of the prolonged mask wearers displayed increased abundance of Staphylococcus, Pseudoalteromonas, Corynebacterium, etc. Meanwhile, the abundance of several genera including Bacteroides, Faecalibacterium, and Agathobacter was decreased. Moreover, we observed that COVID-19 infection history did not affect the composition of nasal microbiota significantly. Additionally, the culture-based analysis revealed that Staphylococcus aureus and Corynebacterium accolens increased, and Staphylococcus epidermidis decreased in the nasal cavity of prolonged mask wearers.

Conclusions

Overall, our study suggests that prolonged face mask wearing can significantly alter the nasal microbiota.

Limited Adaptation of Staphylococcus aureus during Transition from Colonization to Invasive Infection

Staphylococcus aureus carriage is a risk factor for invasive infections. Unique genetic elements favoring the transition from colonizing to invasive phenotype have not yet been identified, and phenotypic adaptation traits are understudied. We therefore assessed phenotypic and genotypic profiles of 11 S. aureus isolate pairs sampled from colonized patients simultaneously suffering from invasive S. aureus infections. Ten out of 11 isolate pairs displayed the same spa and multilocus sequence type, suggesting colonization as an origin for the invasive infection. Systematic analysis of colonizing and invasive isolate pairs showed similar adherence, hemolysis, reproductive fitness properties, antibiotic tolerance, and virulence in a Galleria mellonella infection model, as well as minimal genetic differences. Our results provide insights into the similar phenotypes associated with limited adaptation between colonizing and invasive isolates. Disruption of the physical barriers of mucosa or skin was identified in the majority of patients, further emphasizing colonization as a major risk factor for invasive disease. IMPORTANCE S. aureus is a major pathogen of humans, causing a wide range of diseases. The difficulty to develop a vaccine and antibiotic treatment failure warrant the exploration of novel treatment strategies. Asymptomatic colonization of the human nasal passages is a major risk factor for invasive disease, and decolonization procedures have been effective in preventing invasive infections. However, the transition of S. aureus from a benign colonizer of the nasal passages to a major pathogen is not well understood, and both host and bacterial properties have been discussed as being relevant for this behavioral change. We conducted a thorough investigation of patient-derived strain pairs reflecting colonizing and invasive isolates in a given patient. Although we identified limited genetic adaptation in certain strains, as well as slight differences in adherence capacity among colonizing and invasive isolates, our work suggests that barrier breaches are a key event in the disease continuum of S. aureus.

Microbial characterization of the nasal cavity in patients with allergic rhinitis and non-allergic rhinitis

Introduction

Although recent studies have shown that the human microbiome is involved in the pathogenesis of allergic diseases, the impact of microbiota on allergic rhinitis (AR) and non-allergic rhinitis (nAR) has not been elucidated. The aim of this study was to investigate the differences in the composition of the nasal flora in patients with AR and nAR and their role in the pathogenesis.

Method

From February to September 2022, 35 AR patients and 35 nAR patients admitted to Harbin Medical University's Second Affiliated Hospital, as well as 20 healthy subjects who underwent physical examination during the same period, were subjected to 16SrDNA and metagenomic sequencing of nasal flora.

Results

The microbiota composition of the three groups of study subjects differs significantly. The relative abundance of Vibrio vulnificus and Acinetobacter baumanni in the nasal cavity of AR patients was significantly higher when compared to nAR patients, while the relative abundance of Lactobacillus murinus, Lactobacillus iners, Proteobacteria, Pseudomonadales, and Escherichia coli was lower. In addition, Lactobacillus murinus and Lacttobacillus kunkeei were also negatively correlated with IgE, while Lacttobacillus kunkeei was positively correlated with age. The relative distribution of Faecalibacterium was higher in moderate than in severe AR patients. According to KEGG functional enrichment annotation, ICMT(protein-S-isoprenylcysteine O-methyltransferase,ICMT) is an AR microbiota-specific enzyme that plays a role, while glycan biosynthesis and metabolism are more active in AR microbiota. For AR, the model containing Parabacteroides goldstemii, Sutterella-SP-6FBBBBH3, Pseudoalteromonas luteoviolacea, Lachnospiraceae bacterium-615, and Bacteroides coprocola had the highest the area under the curve (AUC), which was 0.9733(95%CI:0.926-1.000) in the constructed random forest prediction model. The largest AUC for nAR is 0.984(95%CI:0.949-1.000) for the model containing Pseudomonas-SP-LTJR-52, Lachnospiraceae bacterium-615, Prevotella corporis, Anaerococcus vaginalis, and Roseburia inulinivorans.

Conclusion

In conclusion, patients with AR and nAR had significantly different microbiota profiles compared to healthy controls. The results suggest that the nasal microbiota may play a key role in the pathogenesis and symptoms of AR and nAR, providing us with new ideas for the treatment of AR and nAR.

The Fim and FhaB adhesins play a crucial role in nasal cavity infection and Bordetella pertussis transmission in a novel mouse catarrhal infection model

Pulmonary infections caused by Bordetella pertussis used to be the prime cause of infant mortality in the pre-vaccine era and mouse models of pertussis pneumonia served in characterization of B. pertussis virulence mechanisms. However, the biologically most relevant catarrhal disease stage and B. pertussis transmission has not been adequately reproduced in adult mice due to limited proliferation of the human-adapted pathogen on murine nasopharyngeal mucosa. We used immunodeficient C57BL/6J MyD88 KO mice to achieve B. pertussis proliferation to human-like high counts of 10⁸ viable bacteria per nasal cavity to elicit rhinosinusitis accompanied by robust shedding and transmission of B. pertussis bacteria to adult co-housed MyD88 KO mice. Experiments with a comprehensive set of B. pertussis mutants revealed that pertussis toxin, adenylate cyclase toxin-hemolysin, the T3SS effector BteA/BopC and several other known virulence factors were dispensable for nasal cavity infection and B. pertussis transmission in the immunocompromised MyD88 KO mice. In contrast, mutants lacking the filamentous hemagglutinin (FhaB) or fimbriae (Fim) adhesins infected the nasal cavity poorly, shed at low levels and failed to productively infect co-housed MyD88 KO or C57BL/6J mice. FhaB and fimbriae thus appear to play a critical role in B. pertussis transmission. The here-described novel murine model of B. pertussis-induced nasal catarrh opens the way to genetic dissection of host mechanisms involved in B. pertussis shedding and to validation of key bacterial transmission factors that ought to be targeted by future pertussis vaccines.

Pertussis is a strictly human respiratory infectious disease that can be fatal to young children and elderly. The currently used mouse models of intracerebral or pulmonary B. pertussis infection served remarkably well in identification of B. pertussis virulence factors and development of efficacious pertussis vaccines. However, B. pertussis transmission could not be reproduced in adult mice due to limited proliferation of the human pathogen in the upper airways of mice. Therefore, we inoculated nasal cavities of immunodeficient MyD88 knock-out mice to achieve a human-like high level of nasal mucosa infection. This allowed triggering of rhinitis and catarrhal shedding of bacteria from mouse nasal cavity and efficient transmission of the infection onto co-housed adult animals. Testing a set of bacterial mutants, we identified two bacterial adhesins as key transmission factors. Combined with the power of mouse and bacterial genetics, this newly established mouse model of the catarrhal phase of the whooping cough disease will enable deciphering of mechanisms that underlie B. pertussis transmission to new hosts.

Phage Treatment Trial to Eradicate LA-MRSA from Healthy Carrier Pigs

The increase of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) causes a threat to human health. LA-MRSA can be transmitted from animals to animal caretakers, which may further spread MRSA to communities and health care facilities. The objective of this work was to study the efficacy of phage treatment in the eradication of LA-MRSA from healthy carrier pigs. A total of 19 MRSA -positive weanling pigs were assigned to a test (n = 10) and a control group (n = 9). A phage cocktail containing three Staphylococcus phages, or a control buffer was administered to the nares and skin of the pigs three times every two days, after which the phage and MRSA levels in nasal and skin swab samples were monitored for a three-week period. The sensitivity of the strains isolated during the follow-up period to the phage cocktail and each phage individually was analyzed and the pig sera were tested for antibodies against the phages used in the cocktail. The phage treatment did not cause any side effects to the pigs. Phages were found in the skin and nasal samples on the days following the phage applications, but there was no reduction in the MRSA levels in the sampled animals. Phage-resistant strains or phage-specific antibodies were not detected during the experiment. The MRSA load in these healthy carrier animals was only 10-100 CFU/swab or nasal sample, which was likely below the replication threshold of phages. The effectiveness of phage treatment to eradicate MRSA from the pigs could thus not be (reliably) determined.

Surveillance for Colonization, Transmission, and Infection With Methicillin-Susceptible Staphylococcus aureus in a Neonatal Intensive Care Unit

IMPORTANCE

Staphylococcus aureus is one of the leading causes of infections in neonatal intensive care units (NICUs). Most studies in this patient group focus on methicillin-resistant S aureus or the outbreak setting, whereas data for methicillin-susceptible S aureus are limited.

OBJECTIVES

To identify risk factors for S aureus colonization and infections in hospitalized newborns and to investigate S aureus transmission and its dynamics in a nonoutbreak setting.

DESIGN, SETTING, AND PARTICIPANTS

This monocentric cohort study in a tertiary NICU in Heidelberg, Germany, enrolled all hospitalized neonates (n = 590) with at least 1 nasal screening swab positive for S aureus. Data were collected from January 1, 2018, to December 31, 2019.

EXPOSURES

Weekly screening for S aureus colonization was performed for all newborns until discharge.

MAIN OUTCOMES AND MEASURES

The primary end point was any S aureus infection until hospital discharge. Transmission of S aureus and performance of routine typing to detect transmissions were defined as the secondary outcomes of the study.

RESULTS

In total, 590 newborns were enrolled (276 [46.8%] female and 314 [53.2%] male; 220 [37.3%] with birthweight <1500 g; 477 [80.8%] preterm; 449 [76.1%] singletons; 419 [71.5%] delivered via cesarean section). The median length of stay was 26 (range, 10-62) days. Overall, 135 infants (22.9%) were colonized by S aureus at some time during their hospital stay. The median time to first detection was 17 (interquartile range, 11-37) days. The overall incidence of S aureus infection was 1.7% (10 of 590). Low birth weight (<1500 g [odds ratio, 9.3; 95% CI, 5.9-14.6; P < .001]) and longer hospital stay (odds ratio, 2.3; 95% CI, 1.9-2.7; P < .001) were associated with colonization. Nasal carriage was significantly associated with S aureus infection (odds ratio, 8.2; 95% CI, 2.1-32.3; P = .002). A total of 123 of 135 colonization isolates were sequenced. All recoverable infection isolates (4 of 7) of newborns with colonization were genetically identical to the colonizing isolate. Whole-genome sequencing indicated 23 potential transmission clusters.

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that nasal colonization is a relevant risk factor for S aureus infection in a nonoutbreak NICU setting. In colonized newborns, infection and colonization isolates were genetically identical, suggesting that eradication of colonization may be a useful measure to prevent infection. Further investigations are necessary to validate and assess the generalizability of our findings.

Human nasal microbiota

The human nasal passages host a distinct community of microbes. Katherine P. Lemon describes this distinct community, and why it matters so much for human health.

Determination of nasal carriage and skin colonization, antimicrobial susceptibility and genetic relatedness of Staphylococcus aureus isolated from patients with atopic dermatitis in Szczecin, Poland

BACKGROUND

Atopic dermatitis (AD) is one of the most frequent chronic and inflammatory skin condition. AD is characterized by damaged epidermal barrier, xerosis and pruritus of eczematous skin lesions which tend to flare. The duration and frequency of exacerbation of AD symptoms markedly affects the quality of patient life. AD results from the interplay between host genetics, immunity, and environmental factors, however the detailed pathogenesis of this disease is still not entirely cleared. Furthermore, disturbances of the skin microbiota and skin functional impairment predispose to secondary skin infections. Staphylococcus aureus colonizes skin and mucous membranes of 20 to 80% of healthy individuals and of 90% of patients with AD in whom this bacterium is accounted as an important AD exacerbating factor. It is also proven, that S. aureus nasal carriage significantly increases the risk for self-transmission and endogenous infection. In the current study the presence of S. aureus either in nasal vestibule and on lesioned skin of 64 patients with AD enrolled in 10-year autovaccination program was determined. The genetic relatedness of 86 S. aureus isolated from patients nose and skin using Pulsed Field Gel Electrophoresis (PFGE) and antimicrobial susceptibility of all strains to methicillin, erythromycin, clindamycin, mupirocin, gentamicin, amikacin, tetracycline, chloramphenicol and cotrimoxazole was also evaluated.

RESULTS

In total 23 PFGE genotypes and 24 unique patterns were distinguished. 34 patients were S. aureus nasal carriers. Simultaneous presence of S. aureus in nose and on affected skin was found in 16 carriers colonized by indistinguishable or potentially related S. aureus vs 2 carriers colonized with non-related S. aureus in nasal vestibule and on skin. 4 isolates were methicillin resistant (MRSA) among which 3 showed constitutive MLSB resistance phenotype and remaining one was resistant to tetracycline and chloramphenicol. In 4 isolates inducible MLSB resistance phenotype was found, one of them was additionally resistant to tetracycline. 7 S. aureus were mupirocin resistant among them 3 - isolated from one patient, were resistant simultaneously to tetracyclines and chloramphenicol. 7 strains demonstrated resistance to chloramphenicol and susceptibility to all tested antimicrobial agents. The susceptibility to gentamicin, amikacin and cotrimoxazole among all examined S. aureus was confirmed.

CONCLUSION

The obtained results indicated non-clonal structure of S. aureus circulating in AD patients. PFGE results showed the clonal-structure of vast majority of S. aureus isolated from nose and skin from nasal carriers what may prove the autoinfection in these patients. All examined patients the moderate or strong severity of AD was reported. Susceptibility to most antibiotics among isolated strains was also observed.

Association Between Microbiota and Nasal Mucosal Diseases in terms of Immunity

The pathogenesis of nasal inflammatory diseases is related to various factors such as anatomical structure, heredity, and environment. The nasal microbiota play a key role in coordinating immune system functions. Dysfunction of the microbiota has a significant impact on the occurrence and development of nasal inflammation. This review will introduce the positive and negative roles of microbiota involved in immunity surrounding nasal mucosal diseases such as chronic sinusitis and allergic rhinitis. In addition, we will also introduce recent developments in DNA sequencing, metabolomics, and proteomics combined with computation-based bioinformatics.

Circulating sex-steroids and Staphylococcus aureus nasal carriage in a general female population

OBJECTIVE

Staphylococcus aureus is a major human pathogen, and nasal carriers have an increased risk for infection and disease. The exploration of host determinants for nasal carriage is relevant to decrease infection burden. Former studies demonstrate lower carriage prevalence in women and among users of progestin-only contraceptives. The aim of this study was to investigate the possible associations between circulating sex-steroid hormones and nasal carriage of Staphylococcus aureus in a general population.

METHODS

In the population-based sixth Tromsø study (2007-2008) nurses collected nasal swab samples from 724 women aged 30-87 not using any exogenous hormones, and 700 of the women had a repeated nasal swab taken (median interval 28 days). We analysed a panel of serum sex-steroids by liquid chromatography tandem mass spectrometry, and collected information about lifestyle, health and anthropometric measures. Multivariable logistic regression was used to study the association between circulating sex-steroids and Staphylococcus aureus carriage (one swab) and persistent carriage (two swabs), while adjusting for potential confounding factors. Women in luteal phase were excluded in the analysis of androgens.

RESULTS

Staphylococcus aureus persistent nasal carriage prevalence was 22%. One standard deviation increase in testosterone and bioavailable testosterone was associated with lower odds of persistent nasal carriage, (OR = 0.57; 95% CI = 0.35-0.92 and OR = 0.52, 95% CI = 0.30-0.92) respectively. Analysis stratified by menopause gave similar findings. Persistent carriers had lower average levels of androstenedione and DHEA, however, not statistically significant.

CONCLUSION

This large population-based study supports that women with lower levels of circulating testosterone may have increased probability of Staphylococcus aureus persistent carriage.

The upper respiratory tract microbiome of indigenous Orang Asli in north-eastern Peninsular Malaysia

Much microbiome research has focused on populations that are predominantly of European descent, and from narrow demographics that do not capture the socio-economic and lifestyle differences which impact human health. Here we examined the airway microbiomes of the Orang Asli, the indigenous peoples of Malaysia. A total of 130 participants were recruited from two sites in the north-eastern state of Terengganu in Peninsular Malaysia. Using 16S rRNA sequencing, the nasal microbiome was significantly more diverse in those aged 5-17 years compared to 50+ years (p = 0.023) and clustered by age (PERMANOVA analysis of the Bray-Curtis distance, p = 0.001). Hierarchical clustering of Bray-Curtis dissimilarity scores revealed six microbiome clusters. The largest cluster (n = 28; 35.4%) had a marked abundance of Corynebacterium. In the oral microbiomes Streptococcus, Neisseria and Haemophilus were dominant. Using conventional microbiology, high levels of Staphylococcus aureus carriage were observed, particularly in the 18-65 age group (n = 17/36; 47.2% 95% CI: 30.9-63.5). The highest carriage of pneumococci was in the <5 and 5 to 17 year olds, with 57.1% (4/7) and 49.2% (30/61), respectively. Sixteen pneumococcal serotypes were identified, the most common being the nonvaccine-type 23A (14.6%) and the vaccine-type 6B (9.8%). The prevalence of pneumococcal serotypes covered by pneumococcal conjugate vaccines support introduction into a Malaysian national immunisation schedule. In addition, the dominance of Corynebacterium in the airway microbiomes is intriguing given their role as a potentially protective commensal with respect to acute infection and respiratory health.

The Epidome - a species-specific approach to assess the population structure and heterogeneity of Staphylococcus epidermidis colonization and infection

BACKGROUND

Although generally known as a human commensal, Staphylococcus epidermidis is also an opportunistic pathogen that can cause nosocomial infections related to foreign body materials and immunocompromized patients. Infections are often caused by multidrug-resistant (MDR) lineages that are difficult and costly to treat, and can have a major adverse impact on patients' quality of life. Heterogeneity is a common phenomenon in both carriage and infection, but present methodology for detection of this is laborious or expensive. In this study, we present a culture-independent method, labelled Epidome, based on an amplicon sequencing-approach to deliver information beyond species level on primary samples and to elucidate clonality, population structure and temporal stability or niche selection of S. epidermidis communities.

RESULTS

Based on an assessment of > 800 genes from the S. epidermidis core genome, we identified genes with variable regions, which in combination facilitated the differentiation of phylogenetic clusters observed in silico, and allowed classification down to lineage level. A duplex PCR, combined with an amplicon sequencing protocol, and a downstream analysis pipeline were designed to provide subspecies information from primary samples. Additionally, a probe-based qPCR was designed to provide valuable absolute abundance quantification of S. epidermidis. The approach was validated on isolates representing skin commensals and on genomic mock communities with a sensitivity of < 10 copies/μL. The method was furthermore applied to a sample set of primary skin and nasal samples, revealing a high degree of heterogeneity in the S. epidermidis populations. Additionally, the qPCR showed a high degree of variation in absolute abundance of S. epidermidis.

CONCLUSIONS

The Epidome method is designed for use on primary samples to obtain important information on S. epidermidis abundance and diversity beyond species-level to answer questions regarding the emergence and dissemination of nosocomial lineages, investigating clonality of S. epidermidis communities, population dynamics, and niche selection. Our targeted-sequencing method allows rapid differentiation and identification of clinically important nosocomial lineages in low-biomass samples such as skin samples.

Risk assessment studies of the impact of occupational exposure of pharmaceutical workers on the development of antimicrobial drug resistance

Pharmaceutical workers involved with the production of antimicrobial drugs are exposed to various antimicrobial chemicals in different steps of manufacturing such as grinding, sieving, compression, granulation, mixing, and filling. These exposures may lead to the development of multidrug resistance (MDR) in bacteria. Scientific reports on the occupational health hazard of pharmaceutical workers involved in manufacturing antibiotics are scarce. The present study aimed to compare the degree of bacterial resistance in pharmaceutical workers in India to that of individuals not involved in the pharmaceutical field. Twenty male workers from 5 local pharmaceutical companies and 20 male subjects not involved in the pharmaceutical field (non-pharmaceutical subjects) were randomly selected. Nasal fluid and mucus/cough specimens were collected from each subject and were cultured separately at 37 °C for 24 hr to obtain bacterial growth. The cultured species were then identified, isolated, and subjected to microbial sensitivity testing against 18 different antibiotics from 8 different groups by the disk diffusion method. Staphylococcus spp., Pseudomonas spp., and Escherichia coli were identified and isolated from the culture of nasal fluids and mucuses, respectively. All the isolated species of bacteria exhibited significant enhancement of the degree of MDR in pharmaceutical workers compared with non-pharmaceutical subjects. Workers with a longer working history had greater degree of antibiotic resistance and vice versa. It can be certainly considered that the exposure of pharmaceutical workers to antibiotic agents resulted in a high incidence of multidrug resistance. Effective steps should be taken to minimize inherent exposure of pharmaceutical workers to antibiotics during work to prevent antimicrobial drug resistance.

Vancomycin intermediate resistant Staphylococcus aureus in the nasal cavity of asymptomatic individuals: a potential public health challenge

Background

The potential of transmitting multidrug resistant Staphylococcus aureus from asymptomatic individuals to healthy individuals could constitute a great challenge to antimicrobial therapy.

Methods

The antibiograms of the S. aureus from asymptomatic individuals were determined by disk diffusion and agar dilution assay techniques with different antibiotics and vancomycin.

Results

Of the 152 S. aureus isolated, (59)38.8% isolates were multi-drug resistant strains. Streptomycin was the most effective and inhibited (135)88.82% of the isolates while ceftazidime inhibited (24)15.8% of the isolates. While (82)54.0% of the isolates inhibited by cefuroxime had resistant colonies within their inhibition zones (Rc) and ofloxacin inhibited (100)65.8% of the isolates without having resistant colonies within the inhibition zones, ceftazidime inhibited (7)4.6% of the isolates with resistant colonies within the inhibition zones. Subjecting the isolates to vancomycin showed that (27)17.8% were resistant to 2 µg/ml, (43)28.3% were resistant to 4 µg/ml and (27)17.8% of the isolates were simultaneously resistant to both concentrations of vancomycin. Although (100)65.8% of the isolates had MAR_index ≥0.2, (52)34.2% of the isolates had MAR_index ≤ 0.2 and (65)428% of the isolates were considered multidrug resistant strains.

Conclusion

The isolation of multi-drug and vancomycin intermediate resistant strains of S. aureus in high percentage, in this study, presents a great threat to clinicians and general populace. The vancomycin intermediate resistant S. aureus (VISA) in asymptomatic individuals could be a critical concern to the therapeutic dilemma to be added to the presence of multi-drug resistance. A more sustainable therapy must be in place to prevent its dissemination or the outbreak of its infection.

TLR4 Polymorphism, Nasopharyngeal Bacterial Colonization, and the Development of Childhood Asthma: A Prospective Birth-Cohort Study in Finnish Children

We aimed to explore the role of TLR4 (rs4986790) polymorphism in the nasopharyngeal (NP) bacterial colonization and its consequent impact on the development of childhood asthma. A semi-quantitative culture of NP swabs was performed on 473 children at 2 months of age and on 213 children at 13 months of age. TLR4 polymorphism was analyzed for 396 children. Children were followed from birth to the age of 7.5 years and the final outcome was physician-diagnosed asthma. The associations between TLR4 genotype, bacterial colonization, and asthma were analyzed. Children with TLR4 AG or GG genotype were more often colonized with Moraxella catarrhalis at 2 months of age (p = 0.009) and Haemophilus influenzae at 13 months of age (p = 0.018). Children who were colonized with H. influenzae at 13 months of age had a significantly higher risk of later development of asthma (p = 0.004). M. catarrhalis or H. Influenzae colonization at 2 months of age or TLR4 genotype Asp299Gly were not associated with the development of childhood asthma. TLR4 Asp299Gly polymorphism was associated with an increased risk of colonization of M. catarrhalis and H. influenzae in children. The colonization with H. influenzae at 13 months of age was associated with a higher risk of later development of childhood asthma.

Pre-operative methicillin resistant Staphylococcus aureus results do not predict surgical site infections in children undergoing varus derotational osteotomy

Literature regarding the value of pre-operative nasal methicillin resistant Staphylococcus aureus (MRSA) swabs to predict surgical site infections (SSIs) in children undergoing lower extremity surgery is limited. The purpose of our study was to determine if pre-operative nasal MRSA swab results were predictive of SSI development in children undergoing a femoral varus derotational osteotomy (VDRO).Patients who underwent VDRO between 2004-2016 were reviewed to determine pre-operative MRSA colonization rates and SSI devolvement rates. Patients with less than 1 year of follow-up, previous history of infections, or absent pre-operative MRSA swab were excluded. SSI rates of patients with negative MRSA and positive MRSA swab result were compared using the Fisher exact test. Aside from contact isolation precautions, no other changes in treatment were made during inpatient hospital course based on positive pre-operative nasal MRSA swab results.247 patients met the inclusion criteria (mean age: 9.3 ± 3.6 years, 62% male). There were 242 (98%) patients with a negative MRSA swab and 5 (2%) patients with a positive MRSA swab. Out of the 242 patients with a negative MRSA swab, 4 developed an SSI. Of the patients with positive MRSA swab results, 0% (0/5) developed an SSI compared to 1.7% (4/242) of negative MRSA swab results who developed an SSI. Results indicated no significant difference in SSI development rates between the groups (P = 1.00).In this series of children undergoing VDRO surgery, the results of a pre-operative MRSA nasal swab had no relationship to SSI incidence and no impact on clinical patient care. Pre-operative MRSA nasal swabs appear to be of limited benefit for routine pre-operative screening in this patient population.Level III, retrospective comparative.

MRSA Prevalence in Preoperative S. aureus Nasal Culture Isolates is Significantly Different From a Traditional Hospital-wide Antibiogram

Hospital antibiograms, because they are typically derived from samples obtained from hospitalized patients, may overestimate the prevalence of methicillin resistance in S. aureus in individuals presenting to the hospital for surgery. Because hospital antibiograms are commonly used to justify empiric perioperative prophylactic antibiotic selection prior to surgery, this may lead to unnecessary treatment with broad-spectrum antibiotics such as vancomycin. In a single-institution study, we observed that in our hospital antibiogram the proportion of S. aureus that are methicillin-resistant (MRSA) was significantly higher (45%) than isolates in preoperative nasal cultures obtained at the same hospital in outpatients prior to their lower extremity joint replacement surgery (13%): mean difference 0.32, [95% CI 0.25, 0.39], p <0.0001. These data suggest that hospital antibiograms may overstate the true prevalence of MRSA in those at risk for MRSA surgical site infections who present from the outpatient setting.

Staphylococcus epidermidis Contributes to Healthy Maturation of the Nasal Microbiome by Stimulating Antimicrobial Peptide Production

The composition of the human microbiome profoundly impacts human well-being. However, the mechanisms underlying microbiome maturation are poorly understood. The nasal microbiome is of particular importance as a source of many respiratory infections. Here, we performed a large sequencing and culture-based analysis of the human nasal microbiota from different age groups. We observed a significant decline of pathogenic bacteria before adulthood, with an increase of the commensal Staphylococcus epidermidis. In seniors, this effect was partially reversed. In vitro, many S. epidermidis isolates stimulated nasal epithelia to produce antimicrobial peptides, killing pathogenic competitors, while S. epidermidis itself proved highly resistant owing to its exceptional capacity to form biofilms. Furthermore, S. epidermidis isolates with high antimicrobial peptide-inducing and biofilm-forming capacities outcompeted pathogenic bacteria during nasal colonization in vivo. Our study identifies a pivotal role of S. epidermidis in healthy maturation of the nasal microbiome, which is achieved at least in part by symbiotic cooperation with innate host defense.

Hormonal contraceptive use and Staphylococcus aureus nasal and throat carriage in a Norwegian youth population

BACKGROUND

Use of hormonal contraceptives has been associated with Staphylococcus aureus nasal carriage in adult women. However, the role of hormonal contraceptives in S. aureus colonization among adolescents and associations with progestin only contraceptives are unknown.

METHODS

We obtained nasal and throat swab samples from 439 girls aged 17-21 years in the population-based Tromsø study Fit Futures, 2012-2013, Norway, with information on lifestyle, health and biomarkers. We used multivariable logistic regression to study the association between use of hormonal contraceptives and Staphylococcus aureus carriage while adjusting for potential confounding factors.

RESULTS

Staphylococcus aureus nasal carriage prevalence were 34%, 42%, and 61% among progestin-only users, non-users, and progestin-estrogen combination contraceptive users, respectively (P<0.001). Use of combination contraceptives doubled the odds of nasal carriage (non-users reference; OR = 2.31, 95%CI = 1.43-3.74). The OR of nasal carriage was 0.29 among progestin-only users compared to combination contraceptives users (95% CI = 0.12-0.67).

DISCUSSION

In this study, use of combination hormonal contraceptives was associated with higher risk of Staphylococcus aureus nasal carriage in adolescent girls. Experimental design studies are needed to establish the role of exogenous sex steroids in Staphylococcus aureus colonization in women.

Nasal Colonization of Methicillin Resistant Staphylococcus aureus among Healthcare Providers in a Tertiary Care Hospital, Bangladesh

Healthcare providers colonized with Staphylococcus aureus may transmit the organism to patients and community. This study was carried out to determine the rate of nasal colonization of Methicillin resistant Staphylococcus aureus (MRSA) and Vancomycin resistant Staphylococcus aureus (VRSA) among healthcare providers. This cross sectional study was conducted among healthcare providers in a tertiary care hospital, Bangladesh. Nasal swabs from anterior nares of 250 physicians, nurses, and helping staffs working in Dhaka Medical College Hospital were analyzed. Methicillin resistance among MRSA was detected by disc diffusion technique using oxacillin, cefoxitin disc and MIC of oxacillin and methicillin resistance was confirmed by PCR detecting mec-A gene. Considering PCR for mec-A gene as gold standard the sensitivity and specificity of both cefoxitin disc diffusion method and MIC of oxacillin was 100%. Cefoxitin disc diffusion method was better alternative of oxacillin disc diffusion method for detection of MRSA. Nasal colonization by S. aureus was found among 23.2% healthcare providers and 7.2% were colonized with MRSA and no VRSA was detected. MRSA colonization was detected among 5% physicians, 6.43% nurses and 16.67% of helping staffs. Isolated MRSA strains were highly resistant to ciprofloxacin (88.9%), gentamicin (77.8%), erythromycin (72.2%) and Co-trimoxazole (72.2%). All the isolated MRSA were sensitive to linezolid and vancomycin. Periodic screening of healthcare providers should be done to find out MRSA carrier and should be treated accordingly to terminate chain of transmission of the multi-drug resistant organism.

Nasal colonization with methicillin-resistant Staphylococcus aureus associated with elevated homocysteine levels in the general US adults

Given the emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) as a global health threat, understanding the risk factors for MRSA infection in the community may be a reasonable strategy to prevent it. We investigated the associations between serum homocysteine levels and prevalence of nasal colonization with S aureus and MRSA among United States adults. We conducted a cross-sectional analysis of a nationally representative sample of 7832 adults (20 years or older). The main outcome variables were nasal colonization with S aureus and MRSA. Percentages of colonization with S aureus and MRSA were calculated by the quartiles of serum homocysteine. A total of 7832 of 2051 subjects (26.2%) were culture positive for S aureus, 98 (4.8%) of whom had nasal colonization with MRSA. In comparison with subjects having the lowest serum homocysteine, the odds of nasal colonization with MRSA were significantly higher in those with the highest homocysteine (odds ratio, 3.09; 95% confidence interval, 1.11-8.61) in multivariate analysis, adjusted for all confounding variables. By contrast, homocysteine elevation was not significantly associated with S aureus colonization. Nasal colonization with MRSA in the general community was significantly associated with increases in serum homocysteine levels.

A model of chronic, transmissible Otitis Media in mice

Infection and inflammation of the middle ears that characterizes acute and chronic otitis media (OM), is a major reason for doctor visits and antibiotic prescription, particularly among children. Nasopharyngeal pathogens that are commonly associated with OM in humans do not naturally colonize the middle ears of rodents, and experimental models in most cases involve directly injecting large numbers of human pathogens into the middle ear bullae of rodents, where they induce a short-lived acute inflammation but fail to persist. Here we report that Bordetella pseudohinzii, a respiratory pathogen of mice, naturally, efficiently and rapidly ascends the eustachian tubes to colonize the middle ears, causing acute and chronic histopathological changes with progressive decrease in hearing acuity that closely mimics otitis media in humans. Laboratory mice experimentally inoculated intranasally with very low numbers of bacteria consistently have their middle ears colonized and subsequently transmit the bacterium to cage mates. Taking advantage of the specifically engineered and well characterized immune deficiencies available in mice we conducted experiments to uncover different roles of T and B cells in controlling bacterial numbers in the middle ear during chronic OM. The iconic mouse model provides significant advantages for elucidating aspects of host-pathogen interactions in otitis media that are currently not possible using other animal models. This natural model of otitis media permits the study of transmission between hosts, efficient early colonization of the respiratory tract, ascension of the eustachian tube, as well as colonization, pathogenesis and persistence in the middle ear. It also allows the combination of the powerful tools of mouse molecular immunology and bacterial genetics to determine the mechanistic basis for these important processes.

A Bayesian model of acquisition and clearance of bacterial colonization incorporating within-host variation

Bacterial populations that colonize a host can play important roles in host health, including serving as a reservoir that transmits to other hosts and from which invasive strains emerge, thus emphasizing the importance of understanding rates of acquisition and clearance of colonizing populations. Studies of colonization dynamics have been based on assessment of whether serial samples represent a single population or distinct colonization events. With the use of whole genome sequencing to determine genetic distance between isolates, a common solution to estimate acquisition and clearance rates has been to assume a fixed genetic distance threshold below which isolates are considered to represent the same strain. However, this approach is often inadequate to account for the diversity of the underlying within-host evolving population, the time intervals between consecutive measurements, and the uncertainty in the estimated acquisition and clearance rates. Here, we present a fully Bayesian model that provides probabilities of whether two strains should be considered the same, allowing us to determine bacterial clearance and acquisition from genomes sampled over time. Our method explicitly models the within-host variation using population genetic simulation, and the inference is done using a combination of Approximate Bayesian Computation (ABC) and Markov Chain Monte Carlo (MCMC). We validate the method with multiple carefully conducted simulations and demonstrate its use in practice by analyzing a collection of methicillin resistant Staphylococcus aureus (MRSA) isolates from a large recently completed longitudinal clinical study. An R-code implementation of the method is freely available at: https://github.com/mjarvenpaa/bacterial-colonization-model.

The Use of Procalcitonin for Prediction of Pulmonary Bacterial Coinfection in Children With Respiratory Failure Associated With Viral Bronchiolitis

Objectives. Viral bronchiolitis is a frequent cause of pediatric hospitalization and respiratory failure. Procalcitonin (PCT) is a biomarker used to identify serious bacterial infection and can distinguish bacterial and viral infections. Concomitant bacterial pneumonia is not rare in viral bronchiolitis and can lead to a worse clinical course. This study examined the use of PCT in pediatric patients with respiratory failure attributed to viral bronchiolitis to predict concomitant bacterial pneumonia. Methods. This prospective descriptive study evaluated children less than 4 years of age who underwent endotracheal intubation for respiratory failure due to viral bronchiolitis. PCT levels and endotracheal aspirate cultures were obtained at admission. Bacterial pneumonia was defined as at least moderate growth of a single pathogenic organism from endotracheal culture. PCT levels were evaluated in groups with and without concomitant bacterial pneumonia. Results. Thirty-five patients were enrolled between February 2013 and May 2015. All subjects tested positive for at least 1 viral pathogen by nasal wash polymerase chain reaction or enzyme immunoassay. The top viruses obtained were respiratory syncytial virus (n = 15, 42.8%) and rhinovirus (n = 8, 22.9%). The incidence of bacterial pneumonia was 60% (21/35). The PCT median was 0.93 ng/mL (interquartile range = 0.25-6.64) in the bacterial pneumonia group and 1.85 ng/mL (interquartile range = 0.28-7.94) in the nonbacterial pneumonia group. No correlation was found between PCT and bronchiolitis with bacterial coinfection (P = .74). Conclusion. Incidence of bacterial coinfection in patients with respiratory failure and viral bronchiolitis was high. PCT did not predict concomitant bacterial pneumonia in children with viral bronchiolitis.

Face Mask Use and Persistence of Livestock-associated Staphylococcus aureus Nasal Carriage among Industrial Hog Operation Workers and Household Contacts, USA

BACKGROUND

Industrial hog operation (IHO) workers may persistently carry antibiotic-resistant, livestock-associated Staphylococcus aureus in their nasal cavities. It is unclear whether IHO work activities can alter IHO workers' and their household members' exposure to these bacteria.

OBJECTIVE

Our objective was to investigate the relationship of IHO work activities with persistence of antibiotic-resistant, livestock-associated S. aureus nasal carriage among IHO workers and their household members.

METHODS

At biweekly intervals over 4 months, IHO workers and their household members completed questionnaires and provided nasal swabs that were assessed for S. aureus, multidrug-resistant S. aureus (MDRSA), and livestock-associated markers (tetracycline resistance, scn absence, spa type). We examined the association between transient and habitual IHO work activities and S. aureus nasal carriage outcomes.

RESULTS

One hundred one IHO workers and 79 household members completed 1,456 study visits. Face mask use (each 25% increase) was associated with reduced odds of nasal carriage of MDRSA (odds ratio [OR]: 0.65 [95% confidence interval (CI): 0.46, 0.92], tetracycline-resistant S. aureus [OR = 0.74 (95% CI: 0.56, 0.97)], and S. aureus clonal complex (CC) 398/CC9 [OR = 0.77 (95% CI: 0.60, 0.99)]. IHO workers who ever (vs. never) gave pigs injections had higher odds of these outcomes. Among household members, living with an IHO worker who consistently ([Formula: see text] of the time) versus sometimes or never used a face mask was associated with reduced odds of carrying scn-negative S. aureus, tetracycline-resistant S. aureus, and S. aureus CC398/CC9 (OR range: 0.12-0.20, all [Formula: see text]), and consistent IHO worker coveralls use was associated with reduced odds of household member MDRSA carriage only. Living with an IHO worker who habitually had contact with [Formula: see text] hogs (vs. [Formula: see text]) was associated with higher odds of household member livestock-associated S. aureus carriage.

CONCLUSIONS

Consistent face mask use was associated with reduced exposure to antibiotic-resistant, livestock-associated S. aureus among IHO workers and their household members. https://doi.org/10.1289/EHP3453.

Changes in the Gut Microbiota of Urban Subjects during an Immersion in the Traditional Diet and Lifestyle of a Rainforest Village

People living traditional lifestyles have higher gut microbiota diversity than urban subjects. We hypothesized that shifting lifestyles from an urban environment to a traditional rainforest village would lead to changes in the microbiota of visitors, which would become more similar to the microbiota of villagers. Here, we characterized at different time points the microbiota of 7 urban visitors (5 adults and 2 children) staying in a rainforest Amerindian village for 16 days and compared them with a reference collection of samples from age-matched local villagers. We performed a 16S rRNA gene survey of samples from multiple body sites (including fecal, oral, nasal, and skin samples) using Illumina MiSeq sequencing. The main factor segregating the microbiotas of each body site was the human group (i.e., visitors versus villagers), with the visitor microbiota tending to have lower alpha diversity; the lowered alpha diversity was statistically significant in the microbiota of skin and in the children's fecal and oral microbiota. During the rainforest period, all visitors experienced microbiota changes within their personal cloud of variation. For all body sites, the microbiota conformations in the visitor children better matched the microbiota conformations in villagers of the same age than did those of the visitor adults, which showed a lower "microbiota age" than the microbiota of the villagers. The results suggest higher stability in the adult microbiota, with the less resilient children's microbiota responding more to dietary changes.IMPORTANCE Despite the limitations of a small study, our results evidence higher resilience of the gut microbiota with respect to dietary manipulation in adults than in children and urge further studies to understand the extent of microbiota plasticity in response to dietary changes and the mechanisms underlying microbiota resilience. These studies are relevant to the potential of future human pre- and probiotics in preventing or curing microbiota-associated diseases.

Does Staphylococcus aureus nasal decontamination affect the rate of early surgical site infection in adolescent idiopathic scoliosis surgery?

PURPOSE

Surgical site infection (SSI) is a main complication after adolescent idiopathic scoliosis (AIS) surgery. Nasal colonization with S. aureus is a known risk factor for developing nosocomial infections in cardiac surgery. However, the risk in orthopedic surgery remains unclear, especially in spine surgery. This study aims to report the efficacy of a preoperative nasal decontamination program in S. aureus carriers on the incidence of early SSI after AIS posterior surgery.

METHODS

Between January 2014 and July 2017, all AIS patients were screened preoperatively with nasal swabs and decontaminated if positive 5 days before surgery. Early SSI was identified, and microorganisms findings were analyzed within nasal carriage and compared to a previous series published before the decontamination program (2007-2011).

RESULTS

Among the 331 AIS posterior fusion performed during the study period, incidence of positive nasal swab was 23% (n = 75). Those were preoperatively decontaminated. In comparison with the period before the nasal decontamination program, incidence of S. aureus early SSI significantly decreased from 5.1 to 1.3%, p < 0.05. None of those S. aureus decontaminated patients had an early S. aureus SSI. In all cases of S. aureus infections, S. aureus nasal screening was negative with a mean delay of 315 days (± 115) before surgery, which was significantly different from the global cohort (104 days ± 67, p < 0.05).

CONCLUSIONS

Preoperative S. aureus nasal decontamination was associated with a significant decrease in S. aureus SSI. Optimal delay of nasal screening needs to be optimized in order to diagnose intermittent S. aureus carriers. These slides can be retrieved under Electronic Supplementary Material.

Human pharyngeal microbiota in age-related macular degeneration

BACKGROUND

While the aetiology of age-related macular degeneration (AMD)-a major blinding disease-remains unknown, the disease is strongly associated with variants in the complement factor H (CFH) gene. CFH variants also confer susceptibility to invasive infection with several bacterial colonizers of the nasopharyngeal mucosa. This shared susceptibility locus implicates complement deregulation as a common disease mechanism, and suggests the possibility that microbial interactions with host complement may trigger AMD. In this study, we address this possibility by testing the hypothesis that AMD is associated with specific microbial colonization of the human nasopharynx.

RESULTS

High-throughput Illumina sequencing of the V3-V6 region of the microbial 16S ribosomal RNA gene was used to comprehensively and accurately describe the human pharyngeal microbiome, at genus level, in 245 AMD patients and 386 controls. Based on mean and differential microbial abundance analyses, we determined an overview of the pharyngeal microbiota, as well as candidate genera (Prevotella and Gemella) suggesting an association towards AMD health and disease conditions.

CONCLUSIONS

Utilizing an extensive study population from Singapore, our results provided an accurate description of the pharyngeal microbiota profiles in AMD health and disease conditions. Through identification of candidate genera that are different between conditions, we provide preliminary evidence for the existence of microbial triggers for AMD. Ethical approval for this study was obtained through the Singapore Health Clinical Institutional Review Board, reference numbers R799/63/2010 and 2010/585/A.

Staphylococcus aureus colonization and risk of surgical site infection in children undergoing clean elective surgery: A cohort study

Staphylococcus aureus persistently colonizes the skin and nasopharynx of approximately 20% to 30% of individuals, with the highest rates in younger children. To avoid clinical problems for carriers and the spread of S aureus to other hospitalized patients, screening and decolonization of carriers undergoing surgery has been recommended. However, the best approach to patients undergoing clean surgery is not precisely defined. To evaluate whether children carrying S aureus admitted to the hospital for clean elective surgery have an increased risk of postoperative surgical infections, 393 infants and children (77.1% males; mean age ± standard deviation, 7.6 ± 4.5 years) who were scheduled for clean elective surgery procedures were evaluated for S aureus carriage on the day of intervention and 5 days after it. Both anterior nares and pharyngeal swabs were collected. S aureus was identified using the RIDAGENE methicillin-resistant S aureus (MRSA) system (R-Biopharm AG, Darmstadt, Germany), according to the manufacturer's instructions. At admission, 138 (35.1%) children screened positive for S aureus. MRSA was identified in 40 (29.0% of S aureus positive subjects) cases. The carriage rates of S aureus and MRSA varied considerably with age, and in children <2 years old the rate was significantly lower than in any other age group (P < .05). Surgical site infection was demonstrated in 4 out of 109 (3.7%) children who were initially colonized by S aureus and in 5 out of 201 (2.5%) children with a negative screening, without any statistically significant difference between groups (P = .72). None of these children had MRSA. These results seem to suggest that children undergoing clean elective surgery do not need to be screened for S aureus colonization because, although positive, they have no increased risk of surgical site infection. Following this statement, preoperative procedures should be simplified with relevant advantages from a clinical, social, and economic point of view.

Skin and nasal vestibule colonisation by Staphylococcus aureus and its susceptibility to drugs in atopic dermatitis patients

INTRODUCTION

Atopic dermatitis (AD) is a chronic and recurrent disease with an inflammatory background. Genetic and environmental factors are responsible for the occurrence and development of this dermatosis.

OBJECTIVE

The aim of the study was to assess the frequency of colonisation of the nasal vestibule and apparently healthy skin by S. aureus, and to assess dermal lesions for superinfection with S. aureus in AD patients.

MATERIAL AND METHODS

The research was performed on a population of 100 AD patients. Three smears were collected for microbiological investigations: from the anterior nares, from apparently healthy skin and from lesioned skin. On collection, the material was cultured on mediums provided by the bioMerieux and Argenta companies. The strains were identified and their sensitivity to antibiotics assessed by means of the Vitek2 system (bioMerieux).

RESULTS

S. aureus was present in at least one location in 90%. 44% presented S. aureus colonization of apparently healthy skin and within skin lesions. In the case of 23%, this particular pathogen was detected only in skin lesions, whereas 6% had a positive result within the area of apparently healthy skin. In total, S. aureus was detected in the skin of 73%. In 61%, apparently healthy skin had been colonized with S. aureus, whereas in 81% colonization was proved within the skin lesions. S. aureus was detected in the nasal vestibule of 85%. Among the group with S. aureus in their anterior nares, the pathogen was also found on the skin surface of 77%.

CONCLUSIONS

S. aureus colonises skin in most AD patients. Most AD patients carry S. aureus in their nasal vestibules. S. aureus does not seem to colonise healthy skin as often as skin lesions in young people. The vast majority of S. aureus strains were sensitive to local antibiotics. Most S. aureus strains produced penicillinase.

Genomic evolution of Staphylococcus aureus isolates colonizing the nares and progressing to bacteremia

Background

Nasal colonization by Staphylococcus aureus is a key risk factor for bacteremia. The objective of this study is to identify genomic modifications occurring in nasal carriage strains of S. aureus as they progress to bacteremia in a cohort of hospitalized patients.

Methods

Eight patients with S. aureus bacteremia were identified. Genomic sequences of the bloodstream isolates were compared with 57 nasal isolates collected longitudinally prior to the occurrence of bacteremia, which covered a timespan of up to 326 days before bacteremia.

Results

Within each subject, nasal colonizing strains were closely related to bacteremia strains. Within a subject, the number of single nucleotide polymorphisms (SNPs) observed between time points was greater than within a single time point. Co-colonization and strain replacement were observed in one case. In all cases colonization progressed to bacteremia without addition of new virulence genes. In one case, a mutation in the accessory gene regulator gene caused abrogation of agr function.

Conclusion

S. aureus evolves in the human nares at a variable rate. Progression of S. aureus nasal colonization to nosocomial infection is seldom associated with acquisition of new virulence determinants. Mutation in the agr gene with abrogation of function was associated with progression to bacteremia in one case.

Genomic differences between nasal Staphylococcus aureus from hog slaughterhouse workers and their communities

New human pathogens can emerge from the livestock-human interface and spread into human populations through many pathways including livestock products. Occupational contact with livestock is a risk factor for exposure to those pathogens and may cause further spreading of those pathogens in the community. The current study used whole genome sequencing to explore nasal Staphylococcus aureus obtained from hog slaughterhouse workers and their community members, all of whom resided in a livestock-dense region in rural North Carolina. Sequence data were analyzed for lineage distribution, pathogenicity-related genomic features, and mobile genetic elements. We observed evidence of nasal S. aureus differences between hog workers and non-workers. Nasal S. aureus from hog workers showed a greater lineage diversity than nasal S. aureus from community residents. Hog worker isolates were less likely to carry the φSa3 prophage and human-specific immune evasion cluster genes than community resident isolates (φSa3 prophage: 54.5% vs. 91.7%, Benjamini-Hochberg (BH) corrected p = 0.035; immune evasion cluster genes: 66.7% vs. 100%, BH p = 0.021). Hog worker isolates had a lower prevalence and diversity of enterotoxins than community resident isolates, particularly lacking the enterotoxin gene cluster (39.4% vs. 70.8%, BH p = 0.125). Moreover, hog worker isolates harbored more diverse antibiotic resistance genes, with a higher prevalence of carriage of multiple resistance genes, than community resident isolates (75.8% vs. 29.2%, BH p = 0.021). Phylogenetic analysis of all ST5 isolates, the most abundant lineage in the collection, further supported separation of isolates from hog workers and non-workers. Together, our observations suggest impact of occupational contact with livestock on nasal S. aureus colonization and highlight the need for further research on the complex epidemiology of S. aureus at the livestock-human interface.

Genotyping comparison of Mycobacterium leprae isolates by VNTR analysis from nasal samples in a Brazilian endemic region

This study analyzed the genetic diversity by MIRU-VNTR of Mycobacterium leprae isolates from nasal cavities and related to epidemiological and clinical data. The sample consisted of 48 newly diagnosed leprosy cases that tested positive for M. leprae PCR in nasal secretion (NS) attending to the National Reference Center of Dermatology Dona Libania (CDERM), Fortaleza, Brazil. Total DNA was extracted from NS of each patient and used for amplification of four M. leprae VNTR loci. Four clusters of M. leprae isolates were formed with identical genotypes. In the spatial analysis, 12 leprosy cases presented similar genotypes organized into 4 clusters. The most common genotypes in the current study was AC8b: 8, AC9: 7, AC8a: 8, GTA9: 10, which may represent a genotype of circulating strains most often in Ceará. A minimum set of four MIRU-VNTR loci was demonstrated to study the genetic diversity of M. leprae isolates from NS.

Evaluation of 16S rRNA qPCR for detection of Mycobacterium leprae DNA in nasal secretion and skin biopsy samples from multibacillary and paucibacillary leprosy cases

Mycobacterium leprae bacilli are mainly transmitted by the dissemination of nasal aerosols from multibacillary (MB) patients to susceptible individuals through inhalation. The upper respiratory tract represents the main entry and exit routes of M. leprae. Therefore, this study aimed to evaluate the sensitivity and specificity of real-time quantitative polymerase chain reaction (qPCR) in detecting M. leprae in nasal secretion (NS) and skin biopsy (SB) samples from MB and paucibacillary (PB) cases. Fifty-four NS samples were obtained from leprosy patients at the Dona Libânia National Reference Centre for Sanitary Dermatology in Ceará, Brazil. Among them, 19 MB cases provided both NS and SB samples. Bacilloscopy index assays were conducted and qPCR amplification was performed using specific primers for M. leprae 16S rRNA gene, generating a 124-bp fragment. Primer specificity was verified by determining the amplicon melting temperature (Tm = 79.5 °C) and detection limit of qPCR was 20 fg of M. leprae DNA. Results were positive for 89.7 and 73.3% of NS samples from MB and PB cases, respectively. SB samples from MB patients were 100% positive. The number of bacilli detected in NS samples were 1.39 × 103-8.02 × 105, and in SB samples from MB patients were 1.87 × 103-1.50 × 106. Therefore, qPCR assays using SYBR Green targeting M. leprae 16S rRNA region can be employed in detecting M. leprae in nasal swabs from leprosy patients, validating this method for epidemiological studies aiming to identify healthy carriers among household contacts or within populations of an endemic area.

Prediction of surgical site infection in spine surgery from tests of nasal MRSA colonization and drain tip culture

PURPOSE

MRSA is an organism that is a possible risk factor for postoperative SSI. The purpose of the study was to examine relationships among surgical site infection (SSI) after spinal surgery, nasal methicillin-resistant staphylococcus aureus (MRSA) colonization, and wound drain culture results.

METHODS

The subjects were 132 patients who underwent spinal instrumentation surgery. A preoperative nasal swab was used to check for the presence of MRSA colonization, and a wound drain tip culture was performed for detection of SSI. Data from culture studies using nasal samples and those from the distal tip of the wound drain were used for analysis.

RESULTS

Five patients (3.8%) had nasal MRSA, 17 (13%) had positive drain tip cultures, 15 (11%) had SSIs, and 10 (8%) had SSIs with MRSA. Patients with nasal MRSA had a higher rate of detection of bacteria in the drain tip culture (40 vs. 19%, p = 0.065), and the SSI rate was significantly higher in patients with a positive drain tip culture (33 vs. 10%, p = 0.012). The total SSI rate differed significantly between patients with and without nasal MRSA (40 vs. 10%, p = 0.039); however, the SSI with MRSA rate did not differ significantly between these groups.

CONCLUSION

MRSA carriers were not necessarily associated with MRSA infection, but were related to a positive drain tip culture and SSI, which might be due to endogenous skin bacteria. Therefore, possible SSI should be considered in patients with nasal MRSA colonization or bacteria detected in a drain tip culture.

[Comparative Genotyping of Staphylococcus aureus Strains Isolated from Skin Lesions, Nasal Cavities, and Feces of Children with Atopic Dermatitis]

Background

The lesion of skin of the majority atopic dermatitis patients is chronically colonized by bacteria belonging to the species Staphylococcus aureus. Topical antibacterial and anti-inflammatory therapy treatment are often ineffective due to fast recolonization by S. aureus and exacerbation of allergic process.

Aims

Our aim was to determine a frequency of S. aureus colonization in skin lesions, mucous membranes of the nasal cavity and intestine of children with atopic dermatitis, to compare the genotypes of Staphylococcus aureus strains isolated from different biotopes of atopic dermatitis patients, and to clarify whether the intestinal and nasal cavities microbiota may act as a source of S. aureus recolonization of skin lesions.

Materials and Methods

Bacteriological examination of fecal samples, skin, and nasal swabs was conducted in 38 atopic dermatitis patients. The pure bacterial cultures of S. aureus were identified using API Staph (Biomerieux, France) and Vitek 2 MS (Biomerieux, France). Isolates of S. aureus were subjected to genotyping by analysis of rRNA internal 16S-23S rRNA spacer regions and high resolution melting analysis (HMR) of polymorphic spa X-regions.

Results

99% S. aureus strains were successfully identified using MALDI-TOF mass-spectrometry. S. aureus cultures were isolated from all biotopes in 31,6% of children, from skin and nasal cavities — in 42% of cases, from skin and feces — in 2,6% of cases, only from skin — in 10,5%, from nasal cavities and feces — in 2,6%, and only from nasal cavities — in 2,6% of cases. In 8% of children, S. aureus was not detected in any of the biotopes. Genotyping of the isolates enabled the detection of 17 different genotypes. A match between the genotypes of skin and nasal strains, and skin and fecal strains was observed in 88% and 61% of the cases respectively.

Conclusions

The observed a high-frequency matching genotypes suggests the possibility of migration of S. aureus strains inside biotopes in humans and the absence of specialization to colonization of any of the niches.

Virome and bacteriome characterization of children with pneumonia and asthma in Mexico City during winter seasons 2014 and 2015

Background

Acute asthma exacerbations and pneumonia are important causes of morbidity and mortality in children and may coexist in the same children, although symptom overlap may lead to difficulties in diagnosis. Microbial and viral diversity and differential abundance of either may play an important role in infection susceptibility and the development of acute and chronic respiratory diseases.

Objectives

To describe the virome and bacteriome present in the upper respiratory tract of hospitalized children with a clinical diagnosis of asthma and pneumonia during an acute exacerbation and an acute respiratory illness ARI episode respectively.

Methods

During the winter seasons of 2013–2014 and 2014–2015, 134 nasopharyngeal swabs samples of children <15 years of age with ARI hospitalized at a referral hospital for respiratory diseases were selected based on clinical diagnosis of asthma or pneumonia. The virome and bacteriome were characterized using Whole Genome Sequencing (WGS) and in-house bioinformatics analysis pipeline.

Results

The Asthma group was represented mainly by RV-C, BoV-1 and RSV-B and the pneumonia group by Bacteriophage EJ-1 and TTMV. TTV was found in both groups with a similar amount of reads. About bacterial composition Moraxella catarrhalis, Propionibacterium acnes and Acinetobacter were present in asthma and Veillonella parvula and Mycoplasma pneumoniae in pneumonia. Streptococcus pneumoniae and Haemophilus influenzae were mostly found with both asthma and pneumonia.

Conclusions

Our results show a complex viral and bacterial composition in asthma and pneumonia groups with a strong association of RV-C presence in asthmatic children. We observed Streptococcus pneumoniae and Haemophilus influenzae concurrently in both groups.

The nasal microbiome mirrors and potentially shapes olfactory function

Olfactory function is a key sense for human well-being and health, with olfactory dysfunction having been linked to serious diseases. As the microbiome is involved in normal olfactory epithelium development, we explored the relationship between olfactory function (odor threshold, discrimination, identification) and nasal microbiome in 67 healthy volunteers. Twenty-eight subjects were found to have normal olfactory function, 29 had a particularly good sense of smell ("good normosmics") and 10 were hyposmic. Microbial community composition differed significantly between the three olfactory groups. In particular, butyric acid-producing microorganisms were found to be associated with impaired olfactory function. We describe the first insights of the potential interplay between the olfactory epithelium microbial community and olfactory function, and suggest that the microbiome composition is able to mirror and potentially shape olfactory function by producing strong odor compounds.

The association between anterior nares and nasopharyngeal microbiota in infants hospitalized for bronchiolitis

BACKGROUND

The airway microbiome is a subject of great interest for the study of respiratory disease. Anterior nare samples are more accessible than samples from deeper within the nasopharynx. However, the correlation between the microbiota found in the anterior nares and the microbiota found within the nasopharynx is unknown. We assessed the anterior nares and nasopharyngeal microbiota to determine (1) the relation of the microbiota from these two upper airway sites and (2) if associations were maintained between the microbiota from these two sites and two bronchiolitis severity outcomes.

RESULTS

Among 815 infants hospitalized at 17 US centers for bronchiolitis with optimal 16S rRNA gene sequence reads from both nasal swab and nasopharyngeal aspirate samples, there were strong intra-individual correlations in the microbial communities between the two sample types, especially relating to Haemophilus and Moraxella genera. By contrast, we found a high abundance of Staphylococcus genus in the nasal swabs-a pattern not found in the nasopharyngeal samples and not informative when predicting the dominant nasopharyngeal genera. While these disparities may have been due to sample processing differences (i.e., nasal swabs were mailed at ambient temperature to emulate processing of future parent collected swabs while nasopharyngeal aspirates were mailed on dry ice), a previously reported association between Haemophilus-dominant nasopharyngeal microbiota and the increased severity of bronchiolitis was replicated utilizing the nasal swab microbiota and the same outcome measures: intensive care use (adjusted OR 6.43; 95% CI 2.25-20.51; P < 0.001) and hospital length-of-stay (adjusted OR 4.31; 95% CI, 1.73-11.11; P = 0.002). Additionally, Moraxella-dominant nasopharyngeal microbiota was previously identified as protective against intensive care use, a result that was replicated when analyzing the nasal swab microbiota (adjusted OR 0.30; 95% CI, 0.11-0.64; P = 0.01).

CONCLUSIONS

While the microbiota of the anterior nares and the nasopharynx are distinct, there is considerable overlap between the bacterial community compositions from these two anatomic sites. Despite processing differences between the samples, these results indicate that microbiota severity associations from the nasopharynx are recapitulated in the anterior nares, suggesting that nasal swab samples not only are effective sample types, but also can be used to detect microbial risk markers.

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) at a palliative care unit: A prospective single service analysis

BACKGROUND

The emergence of multidrug-resistant bacterial microorganisms is a particular challenge for the health care systems. Little is known about the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Gram-negative bacteria (MDRGNB) in patients of palliative care units (PCU).

AIM

The primary aim of this study was to determine the carriage of MRSA among patients of a PCU at a German University Hospital and to assess whether the positive cases would have been detected by a risk-factor-based screening-approach.

DESIGN

Between February 2014 and January 2015 patients from our PCU were tested for MRSA carriage within 48 hours following admission irrespective of pre-existing risk factors. In addition, risk factors for MRSA colonization were assessed. Samples from the nostrils and, if applicable, from pre-existing wounds were analysed by standardized culture-based laboratory techniques for the presence of MRSA and of other bacteria and fungi. Results from swabs taken prior to admission were also recorded if available.

RESULTS

297 out of 317 patients (93.7%) fulfilled one or more MRSA screening criteria. Swabs from 299 patients were tested. The detection rate was 2.1% for MRSA. All MRSA cases would have been detected by a risk-factor-based screening-approach. Considering the detected cases and the results from swabs taken prior to admission, 4.1% of the patients (n = 13) were diagnosed with MRSA and 4.1% with MDRGNB (n = 13), including two patients with MRSA and MDRGNB (0.6%). The rate of MRSA carriage in PCU patients (4.1%) was elevated compared to the rate seen in the general cohort of patients admitted to our University Hospital (2.7%).

CONCLUSIONS

PCU patients have an increased risk to carry MRSA compared to other hospitalized patients. Although a risk factor-based screening is likely to detect all MRSA carriers amongst PCU patients, we rather recommend a universal screening to avoid the extra effort to identify the few risk factor-negative patients (<7%). As we did not perform a systematic MDRGNB screening, further studies are needed to determine the true prevalence of MDRGNB amongst PCU patients.

Composition and variation of respiratory microbiota in healthy military personnel

Certain occupational and geographical exposures have been associated with an increased risk of lung disease. As a baseline for future studies, we sought to characterize the upper respiratory microbiomes of healthy military personnel in a garrison environment. Nasal, oropharyngeal, and nasopharyngeal swabs were collected from 50 healthy active duty volunteers eight times over the course of one year (1107 swabs, completion rate = 92.25%) and subjected to pyrosequencing of the V1–V3 region of 16S rDNA. Respiratory bacterial taxa were characterized at the genus level, using QIIME 1.8 and the Ribosomal Database Project classifier. High levels of Staphylococcus, Corynebacterium, and Propionibacterium were observed among both nasal and nasopharyngeal microbiota, comprising more than 75% of all operational taxonomical units (OTUs). In contrast, Streptococcus was the sole dominant bacterial genus (approximately 50% of all OTUs) in the oropharynx. The average bacterial diversity was greater in the oropharynx than in the nasal or nasopharyngeal region at all time points. Diversity analysis indicated a significant overlap between nasal and nasopharyngeal samples, whereas oropharyngeal samples formed a cluster distinct from these two regions. The study produced a large set of pyrosequencing data on the V1–V3 region of bacterial 16S rDNA for the respiratory microbiomes of healthy active duty Service Members. Pre-processing of sequencing reads showed good data quality. The derived microbiome profiles were consistent both internally and with previous reports, suggesting their utility for further analyses and association studies based on sequence and demographic data.

Methicillin-Resistant Staphylococcus aureus in a Trauma Population: Does Decolonization Prevent Infection?

The purpose of this study was to determine if a decolonization regimen reduces the frequency of methicillin-resistant Staphylococcus aureus (MRSA) infections and if colonization isolates are genetically related to subsequent infectious strains. Trauma patients admitted to the intensive care unit with positive MRSA nasal swabs were randomized to either daily chlorhexidine gluconate (CHG) baths and mupirocin (MUP) ointment to the nares or soap and water baths and placebo ointment for five days. Nasal swabs performed at the end of treatment and invasive MRSA infections during the remaining hospitalization were compared with the original nasal isolate via polymerase chain reaction for genetic relatedness as well as CHG and MUP resistance genes. Six hundred and seventy-eight intensive care unit admissions were screened, and 92 (13.6%) had positive (+) MRSA nasal swabs over a 22-month period ending in 3/2014. After the five day treatment period, there were 13 (59.1%) +MRSA second nasal swabs for CHG + MUP and 9 (90%) for soap and water baths and placebo, P = 0.114. No isolates tested positive for the MUP or CHG resistance genes mupA and qacA/B but 7 of 20 (35%) contained smr. There were seven (31.8%) MRSA infections in the CHG group and six (60%) for soap, P = 0.244. All 13 patients with MRSA infections had the same MRSA isolate present in the original nasal swab. There was no difference in all-cause Gram-negative or positive infections for CHG versus soap, 12 (54.5%) versus 7 (70%), P = 0.467. CHG + MUP are ineffective in eradicating MRSA from the anterior nares but may reduce the incidence of infection. Subsequent invasive MRSA infections are typically caused by the endogenous colonization strain.

Nasal carriage rate and antibiotic susceptibility pattern of Neisseria meningitidis in healthy Ethiopian children and adolescents: A cross-sectional study

BACKGROUND

Community nasal meningococcal carriage rates are high across Africa. Meningococcal infections are major causes of morbidity and mortality in the continent; especially among children and adolescents. This study aimed to determine the prevalence of nasal carriage and antibiotic susceptibilities of meningococcal isolates from healthy Ethiopian children and adolescents.

METHOD

A cross-sectional study was conducted in one of the sub-cities of Addis Ababa, Ethiopia. Nasal swabs were collected and processed for identification, serogrouping and testing susceptibilities for three antibiotics using standard microbiological techniques. Data on epidemiologic risk factors were collected using a structured questionnaire and the magnitude of their association with carriage was assessed using bivariate and multivariate analysis.

RESULT

A total of 240 samples were collected (115 from males and 125 from females). The mean age of study participants was 11.1 years. The prevalence of nasal carriage for Neisseria meningitidis was 20.4% (49/240). Carriage was significantly higher among children living under crowded conditions (OR 1.268; 95% CI: 1.186-1.355; p = 0.006). The predominant serogroups were W135-20/49 isolates (40.8%) and C-12/49 isolates (24.5%) and 83.7% of meningococci were sensitive for Ciprofloxacin. In contrast, isolates showed high resistance to Ceftriaxone (69.4%) while only 4.2% were sensitive for Penicillin. Multi-drug resistance was documented for 14.3% of the isolates.

CONCLUSIONS

Meningococcal carriage rate was found to be high with higher rates associated with children and adolescents living in crowded living conditions. Predominant isolates were of serogroup W135 and C and the isolates showed marked susceptibility to Ciprofloxacin and resistance to Ceftriaxone and Penicillin.

Nasal and pharyngeal carriage of methicillin-resistant Staphylococcus sciuri among hospitalised patients and healthcare workers in a Serbian university hospital

There has been a paucity of data on methicillin-resistant Staphylococcus sciuri (MRSS) epidemiology in European healthcare settings. The aim of the study was to determine the prevalence of nasal and pharyngeal carriage and diversity of MRSS among inpatients and healthcare workers (HCWs) in the largest healthcare centre in Serbia, and to assess performance of different methods for MRSS screening. Nasal and pharyngeal swabs were obtained from 195 patients and 105 HCWs in different departments. Each swab was inoculated directly onto MRSA-ID, oxacillin-resistance screening agar and mannitol salt agar (MSA) with 2 mg/L of oxacillin. After inoculation, each swab was dipped in Mueller-Hinton broth with 6.5% NaCl and after overnight incubation, subcultured onto oxacillin-MSA. Characterisation of isolated MRSS strains was determined by antimicrobial susceptibility testing, PFGE, SCCmec typing and antimicrobial resistance genes detection. MRSS nasal and pharyngeal carriage rate was high (5%) in our hospital and department-variable. PFGE revealed a possible cross-transmission of MRSS between a patient and an HCW, and dissemination across hospital wards. All analysed isolates were multidrug resistant. Fusidic acid resistance was discovered in 93.7% of isolates, but fusA mutations in EF-G and fusB/C genes were not detected. SCCmec regions of MRSS contained elements of classic methicillin-resistant S. aureus type III. Broth enrichment prior to isolation on oxacillin-MSA was superior to direct cultivation on different media with a sensitivity/specificity of 100% and 88.5%, respectively. MRSS is a significant coloniser of patients and HCWs in the hospital. Further research is needed to investigate the clinical significance of the bacterium in our settings.

Molecular characteristics and antibiotic resistance pattern of Staphylococcus aureus nasal carriage in tertiary care hospitals of Isfahan, Iran

Carriage of S. aureus in the anterior nares seems to play a significant role in the pathogenesis of infection. This study aimed to determine the molecular characteristics and antibiotic susceptibility pattern of S. aureus isolates obtained from the nasal carriage of health care workers (HCWs). This study was performed during July 2014 to July 2015 at three tertiary care hospitals. Nasal samples were collected from the nasal cavity of HCWs. Standard microbiological methods were used for identification of S. aureus isolates. Antibiotic susceptibility pattern was determined by the disc diffusion method. Determination of SCCmec typing and virulence genes was performed by the PCR method. From the isolates of 340 nasal swab samples of HCWs, 65 S. aureus strains (19%) including 22 (33.8%) MRSA were isolated. The highest sensitivity for MRSA isolates was towards vancomycin and rifampicin, each with 90.9%. Overall, 17% (11/65) and 92.3% (60/65) of S. aureus isolates were positive for pvl and hla genes, respectively. The rates of SCCmec types II, III, IV, V and I among MRSA isolates were 36.4 %, 22.7 %, 22.7 %, 9.1% and 4.5% respectively. The results of the present study indicate that S. aureus nasal carriage with potential virulence ability still remains a significant healthcare problem, especially in hospital environments.

The nasal microbiota of dairy farmers is more complex than oral microbiota, reflects occupational exposure, and provides competition for staphylococci

Allergic and autoimmune diseases had been attributed to lack of exposure to biodiversity, an important factor in regulating immune homeostasis in a healthy host. We posit that the microbiome of healthy dairy farmers (DF) will be richer than non-farmers (NF) living in urban settings due to exposure to a greater biodiversity in the dairy environment. However, no studies have investigated the relationships between microbiota of dairy farmers (DF) compared with urban non-farmers (NF). We compared the nasal and oral microbiota of dairy farmers (N_DF, O_DF, respectively) with nasal and oral microbiota of NF in the same geographical area. The N_DF showed high microbial diversity with hundreds of unique genera that reflected environmental/occupational exposures. The nasal and oral microbiomes clustered separately from each other using Principal Coordinate Analysis, and with DF harboring two-fold and 1.5-fold greater exclusive genera in their nose and mouth respectively, than did non-farmers. Additionally, the N_DF group had a lower burden of Staphylococcus spp. suggesting a correlation between higher microbial diversity and competition for colonization by staphylococci. The N_DF samples were negative for the mecA gene, a marker of methicillin-resistance in staphylococci. The lower burden of staphylococci was found to be independent of the abundance of Corynebacterium spp. Exposure to greater biodiversity could enhance microbial competition, thereby reducing colonization with opportunistic pathogens. Future studies will analyze whether exposure to livestock microbiomes offers protection from acute and chronic diseases.