Colonization Of Methicillin-resistant Research Articles

MRSA colonization in health care professionals with varying degrees of exposure to the hospital environment and its susceptibility to mupirocin in a tertiary care centre

Methicillin-resistant (MRSA) is one of the major causes of healthcare associated infections with significant morbidity and mortality. Health care workers act as a carrier in spread of MRSA in hospitals. Use of Mupirocin to eradicate the carrier state is the need of the hour.: This study was undertaken to assess the prevalence of MRSA colonization among health care workers with varying degree of exposure to hospital environment and to know the susceptibility of Mupirocin to MRSA. : Swabs were collected from anterior nares and finger web spaces of 100 health care workers (HCWs). The specimens were processed and colonies of were identified by standard methods. The strains of MRSA were identified by using Cefoxitin (30µg) disk on Muller Hinton agar. The MRSA isolates were then tested for Mupirocin susceptibility.In the present study, 100 nasal and inter digital spaces swabs yielded 15 and 10 MRSA strains respectively. Among the 100 HCWs screened, the majority of MRSA colonization was seen in HCWs with a history of exposure to hospital environment for around 5-10 years or more. All 30 with 15 MRSA strains isolated was sensitive to both 5µg and 200µg Mupirocin disc by Kirby-Bauer disc diffusion method.The high rate of Nasal MRSA carriage among health care workers is alarming. HCWs with long duration of exposure to hospital environment were more colonized with MRSA. More awareness and training sessions on the importance of MRSA and hand hygiene measures to be implemented to prevent MRSA transmission from HCWs to vulnerable patients. We suggest that MRSA screening should be performed for all HCWs and detection of susceptibility of Mupirocin will result in appropriate use of this antibiotic in decolonization.

Prevalence of methicillin resistant and mupirocin-resistant Staphylococcus aureus strains among medical students of Medical University in Warsaw

Staphylococcus aureus is a microorganism, which is able to colonize the human body without any pathogenic effect, but it also can cause life-threatening infections (opportunistic pathogen). Asymptomatic colonization with both methicillin resistant (MRSA) and methicillin susceptible (MSSA) S.aureus strains state is an important predisposing factor for infections. The risk of infection for carriers of MSSA is even three-times higher than for non-colonized people, and in the case of MRSA it is even four-times higher than in MSSA carriers. Carriers can be also a source of infection for other people, especially those belonging to high-risk groups. The drug of choice used for the local eradication of S.aureus is mupirocin (Mup). In recent years, the failure of decolonization therapy has been observed. The aim of the study was to assess and compare the level of colonization of S.aureus (MRSA or MSSA) among medical students and to evaluate the sensitivity of the strains to mupirocin. For MRSA/MupRSA isolates the molecular mechanism of resistance phenotype was determined. 955 swabs from 2014-2016 from pre-clinical students of medicine of the Medical University of Warsaw. The strains were identified using Pastorex-Staph-Plus (BioRad) and/or the VITEK-MS system (Biomerieux), according to manufacturer’s instructions. Susceptibility to methicillin and mupirocin was determined by disk diffusion and/or broth microdilution method, according to EUCAST. The presence of the mecA/mecC and mupA genes were detected with PCR technique. Asymptomatic colonization with S.aureus strains was found in 245/955 (25,7%) students, in particular years in the range of 21,7-29,9%. 243 isolates expressed the MSSA/MupSSA phenotype, one strain was resistant to mupirocin MSSA/MupRSA (genotype mecA/mecC-negative, mupA-positive) and one showed simultaneous resistance to methicillin and mupirocin (mecA/mupA-positive genotype). The level of MRSA and MupRSA colonization was 0,1% and 0,2%, respectively. The level of S.aureus colonization among surveyed students, didn’t differ from the norm for a generally healthy population, but showed an upward trend. The carriage of S.aureus, especially of multi-resistant strains among medical students at the beginning of their clinical activities, consist of a real threat to patients and other people.

Prevalence and Molecular Characterization of Staphylococcus aureus Colonization among Neonatal Intensive Care Units in Taiwan

Background:Staphylococcus aureus, particularly methicillin-resistant (MRSA), is an important pathogen in neonatal intensive care units (NICUs). Carriage of S. aureus is a significant risk factor for subsequent infection. Objectives: To determine the current status of MRSA prevalence among NICU-hospitalized infants in Taiwan, we conducted this pilot island-wide survey. Methods: On two designated dates in 2011, each patient who stayed in the NICUs of 7 participating hospitals was included. Nasal and umbilical swabs were obtained and sent for detection of S. aureus. The prevalence and risk factors for MRSA carriage were analyzed. MRSA strains were tested for antimicrobial susceptibility and underwent molecular characterization. Results: A total of 251 subjects were included. The overall prevalence of S. aureus and MRSA carriage was 13 and 4.4%, respectively. Previous skin and soft tissue infection was the only predictor in multivariate analysis (OR 40.36; 95% CI 2.32-702.64; p = 0.011). Among 11 MRSA isolates, 3 pulsotypes were identified, with one major type (73%). Nine isolates carried a type IV staphylococcal chromosomal cassette, and 2 carried the type V_T. All but one MRSA isolate belonged to linage sequence type 59, the community clone in Taiwan. Conclusions: On a designated date, 4.4% of the infants staying in NICUs in Taiwan carried almost genetically identical community strains of MRSA. MRSA colonization in these infants was significantly associated with previous skin and soft tissue infection.

Detection of methicillin-resistant and methicillin-susceptible Staphylococcus aureus colonization of healthy military personnel by traditional culture, PCR, and mass spectrometry

Methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization is associated with increased rates of infection. Rapid and reliable detection methods are needed to identify colonization of nares and extra-nare sites, particularly given recent reports of oropharynx-only colonization. Detection methods for MRSA/MSSA colonization include culture, PCR, and novel methods such as PCR/electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). We evaluated 101 healthy military members for S. aureus colonization in the nares, oropharynx, axilla, and groin, using CHROMagar S. aureus medium and Xpert SA Nasal Complete PCR for MRSA/MSSA detection. The same subjects were screened in the nares, oropharynx, and groin using PCR/ESI-TOF-MS. By culture, 3 subjects were MRSA-colonized (all oropharynx) and 34 subjects were MSSA-colonized (all 4 sites). PCR detected oropharyngeal MRSA in 2 subjects, which correlated with culture findings. By PCR, 47 subjects were MSSA-colonized (all 4 sites); however, 43 axillary samples were invalid, 39 of which were associated with deodorant/anti-perspirant use (93%, p < 0.01). By PCR/ESI-TOF-MS, 4 subjects were MRSA-colonized, 2 in the nares and 2 in the oropharynx; however, neither of these correlated with positive MRSA cultures. Twenty-eight subjects had MSSA by PCR/ESI-TOF-MS, and 41 were found to have possible MRSA (S. aureus with mecA and coagulase-negative Staphylococcus (CoNS)). The overall 3% MRSA colonization rate is consistent with historical reports, but the oropharynx-only colonization supports more recent findings. In addition, the use of deodorant/anti-perspirant invalidated axillary PCR samples, limiting its utility. Defining MRSA positivity by PCR/ESI-TOF-MS is complicated by co-colonization of S. aureus with CoNS, which can also carry mecA.

Methicillin-resistant Staphylococcus aureus nasal carriage among patients receiving hemodialysis in Taiwan: prevalence rate, molecular characterization and de-colonization

BackgroundStaphylococcus aureus, particularly methicillin resistant (MRSA), is a common pathogen among patients receiving hemodialysis. To evaluate nasal carriage, molecular characterization and effectiveness of decolonization of MRSA among patients receiving hemodialysis in Taiwan, we conducted this study.MethodsFrom January to June 2011, two nasal samplings with a 3-month interval were obtained from patients undergoing hemodialysis in a medical center (CGMH), and in a local hospital (YMH) and sent for detection of MRSA. For MRSA carriers, decolonization procedures were administered. All patients in CGMH were observed if MRSA infections occurred during the study period.ResultsA total of 529 nasal specimens (265 from CGMH and 264 from YMH) were collected from 296 patients (161 from CGMH and 135 from YMH). 233 patients participated in both surveys. Average one-time point MRSA carriage rate was 3.8%, and the rate was up to 6.9% for those with two-time point surveys. No additional significant factor for MRSA carriage was identified. Seventy percent of the 20 colonizing MRSA isolates, though categorized as healthcare-associated strains epidemiologically, shared common molecular characteristics of the local community-associated strains. Only one of the 20 MRSA-colonized patients failed decolonization and had persistent colonization, while without any intervention, 17 (61%) of 28 patients with methicillin-sensitive S. aureus colonization in the first survey had persistent colonization of a genetically indistinguishable strain. Within the study period, two patients (1.24%) in CGMH, one with MRSA colonization (9.1%), developed MRSA infection.ConclusionA substantial proportion of patients receiving hemodialysis in Taiwan had MRSA colonization, mostly genetically community strains. Decolonization procedures may effectively eliminate MRSA colonization and might reduce subsequent MRSA infection in these patients.

Nasal carriage of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in nursing home residents in Bolu,Turkey

This study aimed (a) to provide information on methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization ratio in residents of nursing homes; (b) to determine the effect of hand-washing education given to nursing home residents and employees on nasal carriage of Staphylococcus aureus (NCSA) and (c) to obtain probable risk factors for MRSA colonization of residents in two nursing homes. Seventy-nine volunteers (24 females and 55 males) from Bolu nursing homes were included in the study. Nasal samples were taken with sterile swabs from the anterior nares. Staphylococcus aureus strains were identified using classical methods and genotyping of methicillin resistant strains was done using Arbitrary Primed PCR (AP-PCR). Antibiotic susceptibilities were determined by disk diffusion methods according to NCCLS standards. After first nasal samples were taken, all employees and residents of nursing homes were educated about the methods of hand hygiene over two days. With hand-washing education, the decrease of NCSA rate (initially 43%; after education, 21%) was significant (p < 0.05) while decrease of MRSA carriage (initially 5%, after education 1%) was not (p > 0.05). MRSA carriage was significantly correlated with presence of skin lesions, prior hospitalization within the last six months, and antibiotics usage within the last six months. AP PCR results suggested that residents' carriage of MRSA was the result of the same source. MSSA and MRSA colonization rates were found to be 38% and 5% in nursing homes, respectively. These ratios can decrease with simple precautions like hand-washing after a short education period