Methicillin-resistant Staphylococcus Aureus Nasal Colonization Research Articles

Risk Factors Association for MRSA Nasal Colonization in Preoperative Patients in Azadi Teaching Hospital-Duhok, Kurdistan Region, Iraq

Background: Nasal colonization with Methicillin-resistant Staphylococcus aureus (MRSA) can predispose to subsequent infections in surgical and non-surgical patients, making the management challenging with increased rates of morbidity, mortality and cost burden.
 Objectives: The present study was carried out to evaluate the risk factors of MRSA nasal colonization in preoperative patients in Azadi Teaching Hospital in Duhok Province - Kurdistan Region-Iraq.
 Methods: Nasal swabs were obtained from 150 patients after completing a questionnaire. Conventional laboratory methods were carried out to identify Staphylococcus aureus (S. aureus) and antimicrobial susceptibility test was conducted for recognizing MRSA isolates.
 Results: A total of 41 (27.3%) of 150 patients were MRSA carriers. The mean age of participants MRSA carriers was 35.27±20.40 years old. The highest prevalence rate of nasal colonization with MRSA was in males (27.94%) than females (26.82%). In logistic regression analysis, no significant differences was detected between MRSA carriage and the associated risk factors including age [OR: 0.99 (95 % CI: 0.97- 1.01); P = 0.45], gender [OR: 1.05 (95 % CI: 0.51- 2.17); P = 0.87] and medical comorbidities [OR: 1.11 (95 % CI: 0.42- 2.92); P = 0.82].
 Conclusions: Age, gender and medical comorbidities were not associated common risk factors for nasal colonization of MRSA in preoperative patients. This study should be considered preliminary and studies with larger sample sizes and with using advance molecular tools are needed in the future.

Methicillin-resistant Staphylococcus aureus (MRSA) screening upon inpatient hospital admission: Is there concordance between nasal swab results and samples taken from skin and soft tissue?

Methicillin-resistant Staphylococcus aureus (MRSA) infections are associated with increased mortality and healthcare costs. In 2007, a Veterans' Affairs (VA) hospital implemented a MRSA nasal screening program, following a nationwide VA mandate, in an effort to reduce healthcare-associated MRSA infections. To evaluate the correlation between the nasal screening results for MRSA and culture results of wound and tissue sites. This retrospective study was conducted on inpatients at our VA hospital. Patients were included if they had undergone nasal screening for MRSA plus culture of a wound or tissue site within 30 days of hospital admission. In total, 337 patients underwent nasal screening and wound culture and 211 underwent nasal screening and wound and tissue cultures. The prevalence of MRSA nasal colonization was 14.2% for wound samples and 15.2% for tissue samples. The sensitivities of MRSA nasal screening for detecting MRSA were 64.6% for wound cultures and 65.5% for tissue cultures. Specificities were 86.2% and 88.8% for wound and tissue cultures, respectively. The positive predictive values (PPVs) were 43.7% and 51.2% for wound and tissue cultures, respectively, and the negative predictive values (NPVs) were high at 93.6% and 93.5%, respectively. In cases of wound or tissue samples for which culture results are pending, a negative MRSA nasal swab may be a component of the decision to withhold or discontinue MRSA-active agents.

Exposure to environmental chemical mixtures is associated with nasal colonization by Staphylococcus aureus: NHANES 2001–2004

BackgroundUnderstanding the health effects of exposure to chemical mixtures is critically important given the broad range of concurrent exposures throughout the life-course. While investigations of environmental chemicals and components of the human microbiome are becoming more common, few have examined associations with chemical mixtures. This study assesses the association between exposure to mixtures of 66 different environmental chemicals and nasal colonization of Staphylococcus aureus (SA) and methicillin resistant SA (MRSA). MethodsData came from the National Health and Nutrition Examination Survey (NHANES) 2001–2004. The analytical sample consists of 10,312 participants, age 6 years and older, subdivided into 8 groups with different chemical exposure mixtures. Within each of 6 chemical classes (metals, phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polyfluorochemicals (PFCs), and phenols), weighted quantile sum (WQS) regression was used to analyze the joint association of the component compounds and nasal SA colonization. WQS was also used to assess the joint association of 3 chemical mixtures (metals, metal and PAHs, and metal and triclosan) and nasal MRSA colonization. All regression models were adjusted for confounders. ResultsThe analytical sample was between ages 6–85, slightly more female, and predominantly non-smokers. Prevalence of SA carriage was 29.2%, and MRSA colonization prevalence was 1.2%. Within each chemical class, odds of SA colonization increased statistically significantly with exposure to mixtures of metals (OR = 1.11, 95% CI = 1.02–1.20), phthalates (OR = 1.09, 95% CI = 1.04–1.14), and phenols (OR = 1.08, 95% CI = 1.01–1.15). Exposure to a mixture of metals combined with PAHs was also associated with increased odds of MRSA carriage (OR = 1.38, 95% CI = 1.02–1.86). ConclusionResults indicate an association between multiple environmental chemical mixtures and SA colonization, including MRSA. These findings support the need for further analysis of associations between chemical mixtures and SA colonization, as well as other components of the human microbiome.

Prevalence and Molecular Genetics of Methicillin-Resistant Staphylococcus aureus Colonization in Nursing Homes in Saudi Arabia.

Objective Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main causative agents of nosocomial infections that has posed a major threat to those with compromised immune systems such as nursing home residents. The aim of this study was to determine the rates of MRSA strains and the types of Staphylococcal Cassette Chromosome mec (SCCmec)in nursing homes in Saudi Arabia. Methods A total of 188 nasal swabs were collected from the residents and nursing staff in two nursing homes in Riyadh, Saudi Arabia. All MRSA isolates were tested for antimicrobial susceptibility and analyzed for mecA and SCCmec typing by multiplex PCR assay. Detection of the Panton–Valentine leukocidin (PVL) gene was also tested in all positive MRSA isolates by multiplex PCR using specific primers. Results Among the 188 collected nasal swabs (105 males and 83 females), MRSA colonization rate was 9.04% (11 (5.85%) females and 6 (5.71%) males). About 47% of MRSA were multidrug resistant (MDR) as acquired resistance to beta-lactam, macrolide, and aminoglycoside antibiotics. However, all the MRSA isolates showed susceptibility to vancomycin, tigecycline, and linezolid. All the MRSA isolates (n = 17) were mecA-positive with the SCCmec IVc (n = 7, 41.18%) as the most common SCCmec type followed by SCCmec V (n = 5, 29.41%) and SCCmec IVa (n = 2, 11.76%). The remaining isolates (n = 3) were nontypeable (17.65%). In addition, the PVL toxin gene was only detected in four of the male samples. Conclusion MRSA nasal colonization is a common incident among nursing home residents. The prevalence of community-associated (CA) MRSA (SCCmec IV and V) was more common than hospital-associated (HA) MRSA in our study samples. It is crucial to investigate such rate of incidence, which is a key tool in preventive medicine and would aid in determining health policy and predict emergent outbreaks.

Methicillin-resistant staphylococcus aureus carriage and comorbidity in patients with chronic kidney disease V D stage: a 3-year prospective study

Asymptomatic methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is a confirmed factor that affects the frequency of comorbid bacterial infections and mortality in patients with end-stage renal disease (ESRD).
 The aim was to study the frequency of comorbid conditions and their dynamics in ESRD patients depending on their MRSA status.
 Methods. To prospective cohort study included 265 ESRD patients, 204 of whom were treated by hemodialysis (HD) and 61 by peritoneal dialysis (PD). All recorded comorbidities, their frequency and the dynamics of change, polymorbidity indices, were analyzed depending on whom had MRSA nasal colonization (group 1, n = 92) and without it (group 2, n= 173). The most common cause of ESRD was glomerulonephritis - 161 patients (60.75%). The groups were representative according to gender, age, type of kidney injury and modality of renal replacement therapy (RRT).
 Results. According to the results of a 3-year study investigation, the patients with MRSA carriage had a statistically significant higher level of comorbid conditions frequencies compared to the patients who had opportunistic pathogenic bacteria carriage, namely: prevalence of coronary artery disease (55.4% vs 30.1%, р=0.0001), heart failure (44.6% vs 25.4%, р=0.0015), secondary hyperparathyroidism (61.9% vs 45.1%, р=0,009), chronic obstructive pulmonary disease (31.5% vs 17.3%, р=0.0082), peripheral vascular disease (39.15 vs 17.9%, р=0.0001).
 The increase in the modified polymorphism index in patients of Group 1 and Group 2 during the observation period, was 30 % and 5% respectively.
 One hundred thirty three hospitalization cases were detected during follow-up period: among patients from Group 1- 66 (71.34%) cases, Group 2 - 67 (38.73%); χ² = 26.180, р < 0.0001; RR – 1.8524, 95% ДІ: 1.4760 – 2.3247.
 Conclusions. Asymptomatic MRSA nasal colonization is a factor that can increase the incidence of coexisting diseases as well as the total number of comorbid conditions in dialysis patients.

The relationship between the exposure to healthcare settings and colonization with methicillin-resistant Staphylococcus aureus among medical students.

Medical students who engage in clinical learning in healthcare settings can be potential methicillin-resistant Staphylococcus aureus (MRSA) carriers. This is a descriptive cross-sectional study having a follow-up approach. Three batches of medical students who were studying at the Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka (1st, 3rd and 5th study years of MBBS course) were screened for nasal and axillary MRSA colonization. The first-year students were screened before and 6 months after clinical learning. The knowledge of the students about infection control was scored (percentage) using a questionnaire in the one week before and later one year after the hospital exposure. Data was compared using two-sample t test. The percentage of MRSA colonization was 6.36% (7/110) and 49.57% (59/119) before clinical exposure and after 2.5 years of exposure, respectively (p<0.012). The percentage of correct responses obtained by the students for the questionnaire about infection control was 28% and 66.9% one week before the exposure to the hospitals and one year after the exposure to the hospitals, consecutively. MRSA carriage was significantly associated with the time duration of the clinical training of the medical students. The knowledge of students about infection control was significantly inadequate one week before the hospital exposure and they have gained the knowledge only after being exposed to the hospitals.

PREVALENCE OF NASAL CARRIAGE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AMONG HEALTHCARE WORKERS IN THE DEPARTMENTS OF OTORINOLARYNGOLOGY AND DENTISTRY IN KYIV, UKRAINE

The aim: To obtain the first estimates of the current prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers (HCWs) in the departments of Otorinolaryngology and Dentistry and to determine of genes virulence factors (Panton Valentine Leukocidine (PVL) genes). Materials and methods: We performed a multicenter cross-sectional study. The susceptibility to antibiotics was determined by disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing. The virulence factor encoding genes, mecA, lukS-lukF, were detected by Polymerase Chain Reaction (PCR). Results: Incidence rate of S. aureus nasal carriage among HCWs was 36.2%, whereas MRSA carriage was 17%. Prevalence of MRSA carriage rate was 34.9% in Otorhinolaryngology departments and 9.7% in Dentistry. PCR testing confirmed that all MRSA strains were mecA gene-positive. The virulence factor encoding genes were detected in 82.3% of the S. aureus isolates from HCWs. Among S.aureus, the lukS-lukF genes were detected in over 59% of the strains. The lukS-lukF genes were detected in 55.5% of MRSA and in 58.9% of MSSA strains. LukS-lukF genes were most commonly co-present in MRSA strains. No significant difference was detected between the occurrences of lukS-lukF genes (P > 0.05). Conclusions: Personnell in otorhinolaryngology and dentistry departments have a high rate of nasal colonization of MRSA. This carrier state may be an important risk factor for transmission MRSA from physicians and nurses to patients and vice-versa. Screening for MRSA nasal carriage of HCWs is a key element in enabling infection control measures and early therapeutic decisions.

1130. Vancomycin Use in Pediatric Severe Sepsis at a Freestanding Children’s Hospital

BackgroundSurviving Sepsis Campaign guidelines recommend antibiotics be administered within 1 hour of severe sepsis (SS) onset, but do not suggest which agents to give. Vancomycin (VAN) is often chosen as empiric therapy for severe sepsis (SS) in children without evidence of the prevalence or risk factors for infections requiring VAN. As VAN is associated with significant nephrotoxicity, this study was performed to measure the risk-benefit ratio of empiric VAN use in pediatric sepsis.MethodsThis was a retrospective study of children with SS between 1/1/2015 to 6/30/2018 at the Women and Children’s Hospital of Buffalo, as captured by billing data and sent to state Department of Health for mandated reporting. SS cases were assessed for risk factors for Gram-positive infections, including presence of a central venous line (CVL) or other invasive device; history of MRSA infection or nasal colonization within the last 2 years; skilled nursing facility (SNF) residence; and prolonged hospitalization of >1 month. Invasive infections for which vancomycin is an optimal agent, specifically culture-proven methicillin-resistant Staphylococcus aureus (MRSA), coagulase-negative Staphylococcus (CoNS), and ampicillin-resistant Enterococcus infections, were defined as vancomycin requiring (VAN-req). Acute kidney injury (AKI) was defined as having a serum Creatinine of twice normal per age-related reference values.ResultsOf 304 identified SS cases, 8.9% had VAN-req infections. VAN was empirically given to 58.2% of cases (177); 86.4% ultimately did not have VAN-req infections. 9.2% of all SS cases had AKI at SS onset; this included 15.8% of patients (28) receiving VAN, of which only 1 (3.6%) had a VAN-req infection. History of a past MRSA infection, prolonged hospitalization, SNF residence, and CVL presence were found to be independent risk factors for a VAN-req infection (Table 1). VAN-req infections in patients lacking these four risk factors was 3.1% (4/130).ConclusionVAN was given empirically in the majority of pediatric SS cases, but culture-proven infections requiring the drug were infrequent, especially in patients without specific risk factors. The use of empiric VAN for SS should be guided by well-defined criteria, as the drug’s potential risks are likely to outweigh any benefit in most patients. Disclosures All authors: No reported disclosures.

Homelessness, Personal Hygiene, and MRSA Nasal Colonization among Persons Who Inject Drugs.

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a leading cause of hospitalization and medical visits among individuals experiencing homelessness and also among persons who inject drugs (PWID), populations with significant overlap in urban centers in the USA. While injection drug use is a risk factor for MRSA skin infections, MRSA is also known to transmit easily in crowded, public locations in which individuals have reduced personal hygiene. Individuals in urban centers who experience homelessness or drug addiction may spend significant amounts of time in environments where MRSA can be easily transmitted, and may also experience reduced access to facilities to maintain personal hygiene. We assessed the relationship between homelessness, personal hygiene, and MRSA nasal colonization, a proxy for MRSA infection risk, in a study of PWID in Boston, MA (n = 78). Sleeping in a homeless shelter for at least one night in the last 3months was significantly associated with MRSA nasal colonization (OR 3.0; p = 0.02; 95% CI 1.2, 7.6). Sleeping at more than one place during the last week (considered a metric of elevated housing instability) was also associated with a threefold increase in odds of MRSA nasal colonization (OR 3.1; p = 0.01; 95% CI 1.3, 7.6). MRSA nasal colonization was strongly associated with use of public showers (OR 13.7; p = 0.02; 95% CI 1.4, 132.8), although few people in this study (4 of 78) reported using these public facilities. Sharing bedding with other people was also associated with increased risk of MRSA colonization (OR 2.2; p = 0.05; 95% CI 1.0-4.7). No associations between hand hygiene, frequency of bathing or clothes laundering, or street sleeping were observed. Use of public facilities supporting persons experiencing homelessness and housing instability, including shelters and public showers, is associated with an increased risk of MRSA nasal colonization in this study. Personal hygiene behaviors appear less associated with MRSA nasal colonization. Environmental assessments of MRSA contamination in homeless shelters and public sanitation facilities are warranted so as to inform appropriate intervention activities.

PREVALENCE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS IN SPINAL SURGERY PATIENTS

ABSTRACT Objective The objective of this study was to determine the prevalence of patients with colonization of methicillin-resistant Staphylococcus aureus (MRSA) in the nasal mucosa, who underwent elective spinal procedures. Methods Retrospective study of the medical records of all patients submitted to elective procedures, totaling 125 individuals in the period of 2015 and 2017, performed by two spinal surgeons of the Orthopedics and Traumatology Service of Hospital Mater Dei, Belo Horizonte, Minas Gerais. The pre-operative investigation of MRSA consisted of the collection of a nasal swab for microbiological culture. Results Of the 125 patients evaluated, three (2.4%) showed positive results for MRSA nasal colonization. This prevalence is consistent with the international literature, that ranges from 1.5 to 5.9%. Of these patients none had infection of the surgical wound, probably due to the preoperative prophylactic measures. Conclusions Despite the limitations of the study, we found that the prevalence of carriers of this nasal MRSA population is similar to that of populations worldwide . Level of evidence III; Retrospective Study.

Occupational swine exposure and Hepatitis E virus, Leptospira, Ascaris suum seropositivity and MRSA colonization in Austrian veterinarians, 2017-2018-A cross-sectional study.

We investigated the prevalence of Hepatitis E Virus (HEV), Leptospira and Ascaris suum (A. suum) seropositivity, and of nasal methicillin‐resistant Staphylococcus aureus (MRSA) colonization among Austrian practising veterinarians, and assessed the association with occupational swine livestock exposure. The 261 participants completed a questionnaire on demographics, intensity of occupational swine livestock contact and glove use during handling animals and their secretions. Participants' blood samples were tested for HEV, Leptospira and A. suum seropositivity and nasal swabs cultured for MRSA. We compared swine veterinarians (defined as >3 swine livestock visits/week) to non‐swine veterinarians (≤3 swine livestock visits/week) with regard to the outcomes through calculating prevalence ratio (PR) and 95% confidence interval (CI). Furthermore, the relationship between occupational swine livestock contact and the study outcomes was examined by age (</≥55 years) and glove usage. The prevalence of nasal MRSA colonization was 13.4% (95% CI: 9.3–17.6), of HEV seropositivity 20.8% (95% CI: 15.8–25.7) and A. suum seropositivity 44% (95% CI: 37.7–50.2). The highest anti‐leptospiral antibodies titres were 1:200 (L. hebdomadis) and 1:100 (L. autumnalis, L. caicola) found in three non‐swine veterinarians. Compared to non‐swine veterinarians, swine veterinarians were 1.9 (95% CI: 1.0–3.4) and 1.5 (95%CI: 1.0–2.3) times more likely HEV seropositive and A. suum seropositive, respectively, and 4.8 (95%CI: 2.5; 9.3) times more likely nasally colonized with MRSA. Among glove‐using veterinarians, occupational swine contact was no longer a determinant for HEV seropositivity (PR 1.6; 95% CI: 0.8–2.9). Similar was found for A. suum seropositivity, which was no longer associated with occupational swine livestock contact in the subgroup of glove using, ≥55‐year‐old veterinarians (PR: 1.07; 95% CI: 0.4–3.3). Our findings indicate that >3 occupational swine livestock visits per week is associated with HEV and A. suum seropositivity and nasal MRSA colonization and that glove use may play a putative preventive role in acquiring HEV and A. suum. Further analytical epidemiological studies have to prove the causality of these associations.

Methicillin-resistant Staphylococcus aureus colonization in HIV patients of Arba Minch province, Ethiopia: Carriage rates, antibiotic resistance, and biofilm formation.

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a significant opportunistic pathogen among human immunodeficiency virus (HIV) patients of Ethiopia. This study aimed at delineating the prevalence, antimicrobial resistance, and biofilm-forming potentials of nasally colonized MRSA among HIV patients in the Arba Minch province of Ethiopia. A cross-sectional study was performed in HIV patients who visit anti-retroviral therapy clinic of the Arba Minch Hospital between February and April 2017. Nasal samples were collected and inspected for Staphylococcus following standard procedures. MRSA was identified using cefoxitin disk and antibiotics sensitivity test was performed as per Kirby-Baur disk diffusion method. The formation of biofilm was inspected using both qualitative and quantitative methods. A total of 307 HIV patients were examined. The overall prevalence of S. aureus was found to be 39.7%. The prevalence of MRSA was 20.8%. The rate of nasal colonization of MRSA was relatively higher among females. In bivariate analysis, MRSA colonization was statistically significant in patients with CD4 count ≤350 (p value = 0.002) and co-trimoxazole prophylaxis (p value = 0.003). Concomitant resistance to erythromycin, tetracycline, and co-trimoxazole were 48.4%, 45.3%, and 39.0%, respectively. Invariably, all MRSA isolates were 100% sensitive to vancomycin. Of the 64 MRSA isolates, 18.7% were considered as multidrug-resistant. The rate of biofilm formation was 34.3%. The results revealed a high prevalence rate in the nasal colonization of MRSA in HIV patients.

MRSA Point Prevalence among Health Care Workers in German Rehabilitation Centers: A Multi-Center, Cross-Sectional Study in a Non-Outbreak Setting.

People working in health care services have an increased risk of being infected with methicillin-resistant Staphylococcus aureus (MRSA), though little is known about the prevalence in rehabilitation centers. This cross-sectional study investigated the MRSA prevalence in employees from different rehabilitation centers and aimed to identify risk factors for MRSA transmission. We invited all staff (i.e., with and without patient contact from 22 participating rehabilitation centers; n = 2499) to participate. Study participation included a questionnaire on personal characteristics, lifestyle, personal and occupational risk factors for MRSA and nasal swabs taken by the study team. In total, 1005 persons participated in the study (response: 40.2%). Only four participants carried MRSA (0.40 (95% CI 0.00–1.00) per 100). MRSA carriage did not seem to be occupationally related, as it was found in different occupations with and without direct contact with MRSA patients, as well as in different clinics with different indications and patient clientele. We could not find a clear association between MRSA carriage and potential risk factors due to the low number of cases found. Genotyping revealed the spa types t032 (Barnim epidemic strain) and t1223. Our results suggest a low point prevalence of nasal MRSA colonization in a non-outbreak setting in employees from rehabilitation centers.

1977. Comparative Effectiveness of Linezolid vs. Trimethoprim–Sulfamethoxazole for Acute Bacterial Skin and Skin Structure Infections (ABSSSIs) at a Veterans Affairs Hospital

BackgroundLinezolid (LZD) and trimethoprim–sulfamethoxazole (TMP-SMX) are both used in the treatment of acute bacterial skin and skin structure infection (ABSSSI) with differing adverse event profiles to guide usage, but their comparative efficacies in severe ABSSSI remain unclear.MethodsThis retrospective cohort study evaluated patients admitted to the VA St. Louis Health Care System for treatment of an ABSSSI between April 18, 2000 and October 16, 2017 and discharged with a prescription for ≥5 days of LZD or TMP-SMX. The primary outcome was clinical failure, defined as a composite of an Emergency Department visit, clinic visit, inpatient admission, extension of antibiotics, change of antibiotic regimen for any reason, or the presence of an adverse reaction occurring in the 14 days after completion of the outpatient regimen. Adverse reactions evaluated were acute kidney injury, hyperkalemia, neutropenia, thrombocytopenia, and anemia. The secondary outcome evaluated risk factors for clinical failure with multivariate logistic regression analysis. Potential factors to be included in the analysis were drug choice, duration of intravenous antibiotic use while inpatient (<24 hours, ≥24 hours to ≤48 hours, >48 hours), identification of methicillin-resistant Staphylococcus aureus (MRSA) in culture, MRSA nasal colonization, and incision and drainage.ResultsA total of 139 patients were included in the analysis; 51 treated with LZD and 88 treated with TMP-SMX. Length of hospital stay was greater in the LZD group (6.05 days vs. 3.69 days [P = 0.023]), as was antibiotic use during hospitalization (98% [49/50] vs. 86% [77/90]; P = 0.019). The mean day supply of antibiotic dispensed at discharge was 10.18 in the LZD group and 9.64 in the TMP-SMX group (P = 0.48). Twenty-two percent (11/51) of patients treated with LZD and 18% (16/88) of those treated with TMP-SMX (P = 0.878) experienced clinical failure. Only receipt of antibiotics for 24–48 hours during hospitalization met criteria for inclusion in the multivariate analysis, but was not significantly associated with clinical failure (0.367 [95% CI 0.083–1.63]; P = 0.187).ConclusionThere was no difference in the rate of clinical failure between patients treated with LZD or TMP-SMX for severe ABSSSI.Disclosures All authors: No reported disclosures.

Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus among nasal carriage strains isolated from emergency department patients and healthcare workers in central Taiwan.

Screening and identification of methicillin-resistant Staphylococcus aureus (MRSA) carriage are helpful for controlling MRSA dissemination in hospitals. The aim of our study was to determine the prevalence of nasal carriages and diversity of MRSA among patients and healthcare workers (HCWs) at two regional hospitals in Taiwan. Nasal swabs were obtained prospectively from 204 patients visiting the emergency department (ED) and 326 HCWs in two regional hospitals in Changhua, Taiwan, between February 2015 and June 2015. All the MRSA isolates were further molecularly characterized. Of the 204 participating patients, the nasal carriage rates of S. aureus and MRSA were 22.1% and 7.8%, respectively. For HCWs, the S. aureus and MRSA carriage rates were 26.1% and 6.1%, respectively. There was no statistically significant difference in MRSA carriage rate between patients and HCWs (P=0.447). Patients receiving hemodialysis were significantly associated with MRSA colonization (P=0.012). The leading three sequence types (ST) were ST59 (16, 44.4%), ST45 (11, 30.6%), and ST239 (3, 8.3%) for all 36 MRSA isolates. ST59/SCCmec IV/t437/PVL-negative and ST45/SCCmec V/t1081/PVL-negative were the predominant clones among HCWs (30%) and participating patients (19%), respectively. Overall, a substantial proportion of patients visiting the ED and HCWs harbored CA-MRSA, mostly ST59 strains, in their nares. It is noteworthy that MRSA ST45 strains supplanted ST239 as the second leading nasal MRSA colonization strain in our study.

Effect of Hochuekkito (Buzhongyiqitang) on Nasal Cavity Colonization of Methicillin-Resistant Staphylococcus aureus in Murine Model.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) infections are largely preceded by colonization with MRSA. Hochuekkito is the formula composing 10 herbal medicines in traditional Kampo medicine to treat infirmity and to stimulate immune functions. We evaluated the efficacy of hochuekkito extract (HET) against MRSA colonization using a nasal infection murine model. Methods: We evaluated the effects of HET as follows: (1) the growth inhibition by measuring turbidity of bacterial culture in vitro, (2) the nasal colonization of MRSA by measuring bacterial counts, and (3) the splenocyte proliferation in mice orally treated with HET by the 3H-thymidine uptake assay. Results: HET significant inhibited the growth of MRSA. The colony forming unit (CFU) in the nasal fluid of HET-treated mice was significantly lower than that of HET-untreated mice. When each single crude drug—Astragali radix, Bupleuri radix, Zingiberis rhizoma, and Cimicifugae rhizome—was removed from hochuekkito formula, the effect of the formula significantly weakened. The uptake of 3H-thymidine into murine splenocytes treated with HET was significantly higher than that from untreated mice. The effects of the modified formula described above were also significantly weaker than those of the original formula. Conclusions: Hochuekkito is effective for the treatment of MRSA nasal colonization in the murine model. We suggest HET as the therapeutic candidate for effective therapy on nasal cavity colonization of MRSA in humans.

Methicillin-resistant Staphylococcus aureus nasal carriage and infection among patients with diabetic foot ulcer.

To evaluate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in patients with diabetic foot ulcer (DFU) in Taiwan, and to assess the concordance between colonizing and clinical MRSA isolates from the patients. A total of 354 nasal specimens were collected from 112 to 242 diabetic patients with and without foot ulcer, respectively. MRSA clinical isolates from DFU wound cultures were collected for comparison. Nasal carriage rate of S. aureus and MRSA was similar between diabetic patients with and without foot ulcer (15.2% vs. 16.9% for S. aureus and 5.4% vs. 1.7% for MRSA). Nasal S. aureus colonization was an independent predictor for wound S. aureus infection (Odds ratio [OR]: 5.33, 95% confidence interval [CI]: 1.61-17.59), so did nasal MRSA colonization (OR: 19.09, 95% CI: 2.12-171.91). The levels of glycated hemoglobin, and the usage with immunosuppressant agent were associated with S. aureus nasal colonization while oral hypoglycemic agent usage a protective factor. Sequence type 59/staphylococcal chromosome cassette mec IV or V, the local endemic community-associated clone, accounted for 42% and 70% of the clinical and colonizing isolates, respectively. Six of 10 patients with paired colonizing and clinical isolates, either MRSA or methicillin-sensitive S. aureus, had a genetically identical strain from a single patient. Less than one-fifth of patients with DFU have nasal S. aureus, including MRSA, colonization; however, the colonization is significantly associated with S. aureus diabetic foot infection. Screening for S. aureus colonizing status in DFU patients might have a potential clinical implication.

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

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. 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. 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. 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.

Prevalence and risk factors for MRSA nasal colonization among persons experiencing homelessness in Boston, MA.

Homeless individuals face an elevated risk of methicillin-resistant Staphylococcus aureus (MRSA) infection. Identifying the prevalence and risk factors for MRSA nasal colonization may reduce infection risk. A cross-sectional study was conducted at a health clinic for homeless persons in Boston, MA, USA (n=194). In-person interviews and nasal swab specimens were collected. MRSA isolates were genotyped using pulse-field gel electrophoresis (PFGE) and assessed for antibiotic susceptibility. The prevalence of MRSA nasal colonization was 8.3 %. Seventy-five percent of isolates reflected clonal similarity to USA300. USA100 (18.8 %) and USA500 (6.3 %) were also recovered. Resistance to erythromycin (81.3 %), levofloxacin (31.3 %) and clindamycin (23.1 %) was identified. Recent inpatient status, endocarditis, haemodialysis, heavy drinking, not showering daily and transience were positively associated with MRSA nasal colonization. Carriage of community-acquired MRSA strains predominated in this population, although nosocomial strains co-circulate. Attention to behavioural and hygiene-related risk factors, not typically included in MRSA prevention efforts, may reduce risk.

Methicillin-resistant Staphylococcus aureus in Papua New Guinea: a community nasal colonization prevalence study.

There are few epidemiological data available to inform a national response to community-acquired methicillin-resistant Staphylococcus aureus (MRSA) in Papua New Guinea (PNG). We performed a cross-sectional survey to determine the pattern of MRSA nasal colonization and the diversity of circulating MRSA clones among adults and adolescents in Madang Province, PNG. S. aureus nasal colonization was confirmed in 44 (17.1%) of 257 participants. Four (9.1%) isolates were methicillin resistant. Resistance to other antimicrobial agents was uncommon. Detailed molecular typing of three MRSA isolates demonstrated multiple MRSA clones in this community, of which two carried the Panton-Valentin leukocidin-associated virulence genes. MRSA is likely to account for a clinically important proportion of staphylococcal disease in PNG. There are multiple MRSA clones in PNG. Ongoing surveillance of community and invasive isolates is a critical component of an effective response to the challenge of community-acquired MRSA in this and many other resource-limited contexts.