Nasal Colonization of Humans with Methicillin-Resistant Staphylococcus aureus (MRSA) CC398 with and without Exposure to Pigs

Background: Studies in several European countries and in North America revealed a frequent nasal colonization of livestock with MRSA CC398 and also in humans with direct professional exposure to colonized animals. The study presented here addresses the question of further transmission to non exposed humans. Methods: After selecting 47 farms with colonized pigs in different regions of Germany we sampled the nares of 113 humans working daily with pigs and of their 116 non exposed family members. The same was performed in 18 veterinarians attending pig farms and in 44 of their non exposed family members. For investigating transmission beyond families we samples the nares of 462 pupils attending a secondary school in a high density pig farming area. MRSA were detected by direct culture on selective agar. The isolates were typed by means of spa-sequence typing and classification of SCCmec elements. For attribution of spa sequence types to clonal lineages as defined by multi locus sequence typing we used the BURP algorithm. Antibiotic susceptibility testing was performed by microbroth dilution assay. Results: At the farms investigated 86% of humans exposed and only 4.3% of their family members were found to carry MRSA exhibiting spa-types corresponding to clonal complex CC398. Nasal colonization was also found in 45% of veterinarians caring for pig farms and in 9% of their non exposed family members. Multivariate analysis revealed that antibiotic usage prior to sampling beard no risk with respect to colonization. From 462 pupils only 3 were found colonized, all 3 were living on pig farms. Conclusion: These results indicate that so far the dissemination of MRSA CC398 to non exposed humans is infrequent and probably does not reach beyond familial communities

Clinical effectiveness of rapid tests for methicillin resistant Staphylococcus aureus (MRSA) in hospitalized patients: a systematic review

<p>Abstract</p> <p>Background</p> <p>Methicillin resistant <it>Staphylococcus aureus </it>(MRSA) are often resistant to multiple classes of antibiotics. The research objectives of this systematic review were to evaluate the clinical effectiveness of polymerase chain reaction (PCR) versus chromogenic agar for MRSA screening, and PCR versus no screening for several clinical outcomes, including MRSA colonization and infection rates.</p> <p>Methods</p> <p>An electronic literature search was conducted on studies evaluating polymerase chain reaction techniques and methicillin (also spelled meticillin) resistant <it>Staphylococcus aureus </it>that were published from 1993 onwards using Medline, Medline In-Process & Other Non-Indexed Citations, BIOSIS Previews, and EMBASE. Due to the presence of heterogeneity in the selected studies, the clinical findings of individual studies were described.</p> <p>Results</p> <p>Nine studies that compared screening for MRSA using PCR versus screening using chromogenic agar in a hospital setting, and two studies that compared screening using PCR with no or targeted screening were identified. Some studies found lower MRSA colonization and acquisition, infection, and transmission rates in screening with PCR versus screening with chromogenic agar, and the turnaround time for screening test results was lower for PCR. One study reported a lower number of unnecessary isolation days with screening using PCR versus screening with chromogenic agar, but the proportion of patients isolated was similar between both groups. The turnaround time for test results and number of isolation days were lower for PCR versus chromogenic agar for MRSA screening.</p> <p>Conclusions</p> <p>The use of PCR for MRSA screening demonstrated a lower turnaround time and number of isolation days compared with chromogenic agar. Given the mixed quality and number of studies (11 studies), gaps remain in the published literature and the evidence remains insufficient. In addition to screening, factors such as the number of contacts between healthcare workers and patients, number of patients attended by one healthcare worker per day, probability of colonization among healthcare workers, and MRSA status of hospital shared equipment and hospital environment must be considered to control the transmission of MRSA in a hospital setting.</p

Modeling methicillin-resistant Staphylococcus aureus in hospitals: Transmission dynamics, antibiotic usage and its history

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in many hospital settings, posing substantial threats and economic burdens worldwide. METHODS: We propose mathematical models to investigate the transmission dynamics of MRSA and determine factors that influence the prevalence of MRSA infection when antibiotics are given to patients to treat or prevent infections with either MRSA itself or other bacterial pathogens. RESULTS: Our results suggest that: (i) MRSA always persists in the hospital when colonized and infected patients are admitted; (ii) the longer the duration of treatment of infected patients and the lower the probability of successful treatment will increase the prevalence of MRSA infection; (iii) the longer the duration of contamination of health care workers (HCWs) and the more their contacts with patients may increase the prevalence of MRSA infection; (iv) possible ways to control the prevalence of MRSA infection include treating patients with antibiotic history as quickly and efficiently as possible, screening and isolating colonized and infected patients at admission, and compliance with strict hand-washing rules by HCWs. CONCLUSION: Our modeling studies offer an approach to investigating MRSA infection in hospital settings and the impact of antibiotic history on the incidence of infection. Our findings suggest important influences on the prevalence of MRSA infection which may be useful in designing control policies

Dogs Leaving the ICU Carry a Very Large Multi-Drug Resistant Enterococcal Population with Capacity for Biofilm Formation and Horizontal Gene Transfer

The enterococcal community from feces of seven dogs treated with antibiotics for 2–9 days in the veterinary intensive care unit (ICU) was characterized. Both, culture-based approach and culture-independent 16S rDNA amplicon 454 pyrosequencing, revealed an abnormally large enterococcal community: 1.4±0.8×108 CFU gram−1 of feces and 48.9±11.5% of the total 16,228 sequences, respectively. The diversity of the overall microbial community was very low which likely reflects a high selective antibiotic pressure. The enterococcal diversity based on 210 isolates was also low as represented by Enterococcus faecium (54.6%) and Enterococcus faecalis (45.4%). E. faecium was frequently resistant to enrofloxacin (97.3%), ampicillin (96.5%), tetracycline (84.1%), doxycycline (60.2%), erythromycin (53.1%), gentamicin (48.7%), streptomycin (42.5%), and nitrofurantoin (26.5%). In E. faecalis, resistance was common to tetracycline (59.6%), erythromycin (56.4%), doxycycline (53.2%), and enrofloxacin (31.9%). No resistance was detected to vancomycin, tigecycline, linezolid, and quinupristin/dalfopristin in either species. Many isolates carried virulence traits including gelatinase, aggregation substance, cytolysin, and enterococcal surface protein. All E. faecalis strains were biofilm formers in vitro and this phenotype correlated with the presence of gelE and/or esp. In vitro intra-species conjugation assays demonstrated that E. faecium were capable of transferring tetracycline, doxycycline, streptomycin, gentamicin, and erythromycin resistance traits to human clinical strains. Multi-locus variable number tandem repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE) of E. faecium strains showed very low genotypic diversity. Interestingly, three E. faecium clones were shared among four dogs suggesting their nosocomial origin. Furthermore, multi-locus sequence typing (MLST) of nine representative MLVA types revealed that six sequence types (STs) originating from five dogs were identical or closely related to STs of human clinical isolates and isolates from hospital outbreaks. It is recommended to restrict close physical contact between pets released from the ICU and their owners to avoid potential health risks

White matter lesions and encephalopathy in patients treated for primary central nervous system lymphoma

A retrospective analysis of the clinical presentations and neuroimaging characteristics of 33 patients with a primary central nervous system lymphoma (PCNL) who received cranial radiotherapy was performed to assess incidence of and risk factors for radiation-induced encephalopathy. CT and MRI scans were revised by a neurologist and a radiologist in conference. White matter abnormalities before and after radiotherapy on the last scan before recurrence were quantified according to a semi-quantitative scale. All available medical records were retrieved and reviewed with respect to demographic and tumor-related variables, treatment modalities, disease-free and overall survival and clinical symptoms and signs of encephalopathy. CT and MRI scans showed severe white matter lesions in 75% of 20 patients and in 86% of patients aged more than 60 years. Forty percent of patients presented with new clinical signs of cognitive impairment a median of 14.5 months after initial diagnosis (8.5 months after radiotherapy). The risk of white matter lesions appeared greater in patients aged > 60 (RR 1.2, 95% CI = 0.8-2.0), in patients with prior white matter lesions (RR 1.3, 95% CI = 0.8-2.1) and in patients with multifocal cerebral lymphoma (RR 1.5, 95% CI = 1.0-2.1). In conclusion, the risk of white matter lesions and clinical symptoms and signs of encephalopathy is high in patients treated by radiotherapy for PCNL. The risk appears to be greatest in older patients, patients with multifocal tumor and in those with prior white matter lesions on CT or MRI

Tongue force in patients with myasthenia gravis

Objectives - The aim was to study tongue force in patients with bulbar myasthenia gravis and compare it with that of patients with ocular myasthenia gravis, patients in clinical remission who previously suffered from bulbar myasthenia gravis, and healthy subjects. Material and methods - Tongue force was measured with a tongue force transducer in cranial and lateral directions, which coincide with the directions in which the tongue exerts force during swallowing, speech, and mastication. Results - Tongue force in lateral direction was significantly decreased in patients with bulbar myasthenia gravis. In addition, our findings suggest an incomplete recovery of lateral tongue force in the patients of the remission group. Conclusion - Our tongue force measurements may be useful for longitudinal evaluation of therapy in individual patients and also in studies of therapy efficacy in matched groups of patients if the influence of factors such as age, dental state, and sex is taken into account

Patient and other factors influencing the prescribing of cardiovascular prevention therapy in the general practice setting with and without nurse assessment

BACKGROUND: Although guidelines indicate when patients are eligible for antihypertensives and statins, little is known about whether general practitioners (GPs) follow this guidance. OBJECTIVE: To determine the factors influencing GPs decisions to prescribe cardiovascular prevention drugs. DESIGN OF STUDY: Secondary analysis of data collected on patients whose cardiovascular risk factors were measured as part of a controlled study comparing nurse-led risk assessment (four practices) with GP-led risk assessment (two practices). SETTING: Six general practices in the West Midlands, England. PATIENTS: Five hundred patients: 297 assessed by the project nurse, 203 assessed by their GP. MEASUREMENTS: Cardiovascular risk factor data and whether statins or antihypertensives were prescribed. Multivariable logistic regression models investigated the relationship between prescription of preventive treatments and cardiovascular risk factors. RESULTS: Among patients assessed by their GP, statin prescribing was significantly associated only with a total cholesterol concentration >/= 7 mmol/L and antihypertensive prescribing only with blood pressure >/= 160/100 mm Hg. Patients prescribed an antihypertensive by their GP were five times more likely to be prescribed a statin. Among patients assessed by the project nurse, statin prescribing was significantly associated with age, sex, and all major cardiovascular risk factors. Antihypertensive prescribing was associated with blood pressures >/= 140/90 mm Hg and with 10-year cardiovascular risk. LIMITATIONS: Generalizability is limited, as this is a small analysis in the context of a specific cardiovascular prevention program. CONCLUSIONS: GP prescribing of preventive treatments appears to be largely determined by elevation of a single risk factor. When patients were assessed by the project nurse, prescribing was much more consistent with established guidelines