Methicillin-resistant Staphylococcus Aureus Prevalence Rates Research Articles

Prevalence of Methicillin Resistant Staphylococcus aureus Infections among Hospitalized Wound Patients from Selected Tertiary Hospitals within Enugu Metropolis

The incidence of Staphylococcus aureus infection especially in wound infections continues to rise. This study was aimed to evaluate the prevalence of methicillin resistant Staphylococcus aureus in hospitalized patients with wound infections in selected tertiary hospitals within Enugu metropolis. A total of 385 samples comprising mainly of wound swabs were collected using Levine’s technique and cultured on blood agar, MacConkey agar and Mannitol salt agar. Staphylococcus aureus was identified based on their conventional cultural characteristics, gram staining reactions and biochemical tests. Statistical analysis was done using Statistical Package for Social Sciences (SPSS) 25.0 package. A total of 188 (48.8%) Staphylococcus aureus were isolated from 385 patients with wound infections. Of 188 Staphylococcus aureus isolates, 86 (22.3%) were identified as methicillin resistant Staphylococcus aureus (MRSA) and 102(26.5%), methicillin susceptible Staphylococcus aureus (MSSA) respectively. The prevalence rate of MRSA according to the gender of the participants was 37(9.6%) for males and 49(12.7%) for the females with a mean age of 31.77. Generally, the isolates showed the highest resistance to Ampicillin (100%), Penicillin (100%) and Cefoxitin (100%) and were moderately sensitive to Clindamycin (52.3%) and Gentamycin (54.7%). No statistical significance was established (P>0.05) among these factors. This study highlighted high prevalence of MRSA among hospitalized wound patients and as such, the need for infection control strengthening in hospitals cannot be overemphasized.

Prevalence and Antimicrobial Resistance Profile of Methicillin Resistant Staphylococcus aureus strains Isolated from Food Products and Food Handlers in Egypt

The study aimed to determine the prevalence and phenotypic antimicrobial resistance pattern of Methicillin Resistant Staphylococcus aureus (MRSA) isolated from food products and food handlers at different retail outlets and superstores in Alexandria city, Egypt. A total of 100 food products including raw milk, Damietta cheese, beef burger, sausage, and chicken pane (20 of each) as well as 100 hand swabs were randomly collected from 100 food handlers and screened for the presence of MRSA using MRSA selective agar medium. MRSA isolate was confirmed from each nuc /mecA PCR-positive sample. The overall prevalence rate of MRSA in food products and food handlers was 12% and 5%, respectively. Concerning the food products samples, the highest rate of isolation was recorded in the examined samples of beef burger (20%), followed by sausage (15%) then raw milk and chicken pane (10%) and finally Damietta cheese (5%). The antimicrobial susceptibility testing of the 12 MRSA isolates from food products samples clarified that all (100%) MRSA isolates showed resistance to Cefoxitin and Penicillin G. On the contrary, 100% of the isolates were sensitive to Ceftaroline and Linezolid. Regarding food handlers, prevalence rate was 5.3% in males and 4.2% in females. The phenotypic antimicrobial resistance pattern of the 5 MRSA isolates from food handlers revealed that all (100%) MRSA isolates exhibited resistance to Cefoxitin and Penicillin G. Conversely, 100% of the isolates were sensitive to Ceftaroline and Linezolid. The results of the current study suggest that raw food products may have been contaminated with MDR MRSA strains which could be a potential public health risk. Moreover, these findings unequivocally show the need for enhanced hygiene standards to minimize the risk of occupational and food-borne illness associated with handling and/or consuming raw animal food products harboring MRSA.

Antibiotic Sensitivity to Methicillin and Methicillin Plus Macrolide- Lincosamide-Streptogramins Resistant Staphylococcus Aureus

This study was conducted from May 2018 to Oct 2019 to determine the culture and sensitivity pattern of Methicillin resistant Staphylococcus aureus (MRSA) and MRSA with Macrolide Lincosamide and Streptogramin-B (MLS-B) antibiotics in a tertiary care hospital of Nowshera. A total of 235 isolates were studies and 86 samples showed MRSA. The prevalence rate of MRSA was 89/235 (37.87%). Out of 86 isolates with MRSA, 19 (22.09%) were also resistant to MLS-B antibiotics.Regarding gender specification, 52 (60.5%) were females and 34 (39.5%) were males. The mean age with standard deviation of patients was 29 + 6.8 years. The sensitivity pattern to MRSA was; Vancomycin 100%, Linezolid 100%, Rifampicin 86.04%, Clindamycin, 73.25%, Fusidic acid 60.46%, Erythromycin 44.18%., Doxycyclin 32.55%, levofloxacin 16.27%, Gentamycin 13.95% and Ciprofloxacin 11. 62%. Sensitivity of Vancomycin & Linezolid was 100% in MRSA and MLS-B resistant isolates, and should be kept reserved for MRSA cases to avoid misuse of antibiotics and to reduce resistance.

21. Association of MRSA Prevalence and Hospital-level Antibiotic Use: A Retrospective Study Across 122 Acute-care Hospitals

BackgroundThe prevalence of methicillin-resistant Staphylococcus aureus (MRSA), varies across geographic regions, which could contribute to regional variation in antibiotic use. In this study, we evaluated whether local MRSA prevalence rates were associated with hospital-level antibiotic use across the Veterans Health Administration (VHA).MethodsThis retrospective cohort included all acute-care patients admitted in VHA hospitals during 2016. Anti-MRSA antibiotics were identified per National Healthcare Safety Network definitions and use was quantified as days-of-therapy (DOT) per 1000 days-present. Hospital-level MRSA prevalence (colonization and/or infection) was determined by calculating the proportion of admissions with a positive MRSA nasal swab and/or a MRSA-positive clinical culture obtained ≤1 day before or ≤2 days after admission. Negative binomial regression models were used to determine the association between a hospital’s MRSA prevalence and its antibiotic use, after accounting for intra-hospital clustering, patient case-mix, month of admission, and use of hospital-based stewardship strategies.ResultsThere were 548,476 admissions across 122 hospitals. The median rate of MRSA prevalence at admission was 8.0% (IQR 6.7–9.7%). Hospital level median use of anti-MRSA and total antibiotics was 96.5 (interquartile range [IQR] 81.1–116.9) and 562.1 (IQR 505.9–631.6) DOT per 1,000 days-present, respectively. In a hospital-level risk adjusted analysis, a hospital’s MRSA prevalance was significantly associated with its monthly use of both anti-MRSA and total antibiotics (IRR=1.05, 95% 1.02–1.07; IRR=1.02, 95% CI, 1.01–1.03). A 5% increase in the hospital’s MRSA prevalence was associated with an increase in the monthly use of anti-MRSA antibiotics and total antibiotics by 23.6 and 8.3 DOT per 1,000 days-present, respectively.ConclusionHigher hospital-level MRSA prevalence was associated with significantly higher rates of antibiotic utilization, even after adjusting for case-mix and reported antibiotic stewardship strategies. Future benchmarking of anti-MRSA antibiotic use across hospitals may need to risk-adjust using baseline rates of MRSA prevalence.Disclosures Daniel J. Livorsi, MD, MSc, Merck and Company, Inc (Research Grant or Support) Rajeshwari Nair, PhD, Merck and Company, Inc. (Research Grant or Support)

Stethoscope, A Unique Home of Staphylococcus Aureus in Hospitals.

Background: Nosocomial infections are the hospital acquired infections which are leading cause of mortality and disability among patients admitted in hospitals. Microorganism colonization on stethoscope’s diaphragm is the main cause of disease spread. Stethoscopes are well known medical equipment fomites for Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA). In Pakistan and India nosocomial bacterial infections, methicillin-resistant Staphylococcus aureus (MRSA) has much higher prevalence as compared to Northern Europe. Moreover, in Pakistan, the prevalence rate of MRSA is estimated as 35-45 %. Objective: To determine the frequency of Staphylococcus aureus present on diaphragms of stethoscopes in a tertiary care hospital, Islamabad. Methodology: The descriptive cross-sectional study was performed at tertiary care hospital in Islamabad. consecutive non-probability sampling technique was used and total sample size of 76 stethoscopes was calculated. Microbial samples were taken by rubbing on whole diaphragm of stethoscope. Later, the sample was incubated with a suitable growth medium for 48-72 hours at 36-37 0C temperature. Staphylococcus aureus appeared and these isolates were placed on agar plates with pre-impregnated antibiotics in different zones and incubated overnight and bacterial growth was observed. The species of staph. aureus which showed resistance to penicillin’s and cephalosporin were known as methicillin-resistant Staphylococcus aureus (MRSA). Conclusion : Staphylococcus aureus and MRSA related nosocomial infections are one of the common cause of prolong stay of patients in the hospitals. Contaminated stethoscope in hospital settings can transmit Staphylococcus aureus and MRSA in patients. Proper and frequent disinfection of stethoscopes prevents the cross infection of Staphylococcus aureus and MRSA.

Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and use of tunneled hemodialysis catheters

Background: Hemodialysis patients are at higher risk of contracting infections particularly methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a serious infection and could be fatal within hours to days if undiagnosed. Dialysis catheter commonly known as permacath is a tunnel catheter used for maintenance hemodialysis which is associated with serious complications, especially infections and thrombosis. Different methodologies were designed and tested to determine the relation of infection with permcath. The use of a cuff was thought to prevent catheter related infections but none proved beneficial.1 This finding was supported further in a systematic review conducted in 2009.2 Usage of permacath is on the rise despite awareness of its higher risk of morbidities and mortalities which is contrary to the slogan of Fistula First Initiative.3 We aimed to evaluate the prevalence of MRSA infections in hemodialysis patients with tunneled hemodialysis catheters. Methods: This is a retrospective, qualitative cross-sectional and non-experimental single center study conducted at Sultan Qaboos University Hospital (SQUH) Hemodialysis Unit over eight years. Inclusion criteria include: Adult patients >18 years of age with diagnosis of end stage renal disease requiring hemodialysis. Exclusion criteria included age < 18 years old and patients on peritoneal dialysis. Records of hemodialysis patients from 1st January 2010 through 6th May 2018 were retrieved through TrackCare (electronic medical records). The patients were divided into two groups. Positive MRSA infection (defined as a positive Gram stain with cocci in clusters and which was further confirmed by positive DNA polymerase chain reaction (PCR) for MRSA) either from the periphery or central line or pus swab from the catheter tunnel site at the time of admission or during hospitalization.4 The remaining screened patients were classified as negative MRSA. Informed consent was waived as it is a retrospective study and our work was based on collecting information from TrackCare. All patients’ data were de-identified prior to analysis. Results: From 2010 to 2018, 1356 hemodialysis patients were identified within the hospital information system (HIS). Based on our inclusion criteria, a total of 1064 screened patients were included in our study. Those remaining who were not screened were been excluded. Fifteen patients were detected positive with MRSA infection (Figure 1), 12 patients had permacath and three had arteriovenous fistula (AVF). Overall, the prevalence of MRSA infection was 1.1% (12/1064) in hemodialysis patients with tunneled catheters. Conclusions: In our study, the MRSA prevalence rate was lower than the international reported statistics (4.2–6.5 per 100 patients).5 This supports the use of adequate infection control policies and practices adopted in the unit. We propose that fistula should be the preferred access option for the maintenance hemodialysis. However, in cases where catheter is the only option, due to whatever reason, then using chlorhexidine impregnated dressings in addition to standard catheter care techniques result in reduced infection incidence. Furthermore, use of topical antibiotics at catheter exit sites can reduce the risk of infection.

The prevalence of methicillin-resistant Staphylococcus aureus among diabetic patients: a meta-analysis

AimsDiabetic patients have multiple risk factors for colonisation with methicillin-resistant Staphylococcus aureus (MRSA), a nosocomial pathogen associated with significant morbidity and mortality. This meta-analysis was conducted to estimate the prevalence of MRSA among diabetic patients.MethodsThe MEDLINE, Embase, BIOSIS, and Web of Science databases were searched for studies published up to May 2018 that reported primary data on the prevalence of MRSA in 10 or more diabetic patients. Two authors independently assessed study eligibility and extracted the data. The main outcomes were the pooled prevalence rates of MRSA colonisation and infection among diabetic populations.ResultsEligible data sets were divided into three groups containing data about the prevalence of MRSA colonisation or in diabetic foot or other infections. From 23 data sets, the prevalence of MRSA colonisation among 11577 diabetics was 9.20% (95% CI, 6.26–12.63%). Comparison of data from 14 studies that examined diabetic and non-diabetic patients found that diabetics had a 4.75% greater colonisation rate (P < 0.0001). From 41 data sets, the prevalence of MRSA in 10994 diabetic foot infection patients was 16.78% (95% CI, 13.21–20.68%). Among 2147 non-foot skin and soft-tissue infections, the MRSA prevalence rate was 18.03% (95% CI, 6.64–33.41).ConclusionsThe prevalence of MRSA colonisation among diabetic patients is often higher than among non-diabetics; this may make targeted screening attractive. In the UK, many diabetic patients may already be covered by the current screening policies. The prevalence and impact of MRSA among diabetic healthcare workers requires further research. The high prevalence of MRSA among diabetic foot infections may have implications for antimicrobial resistance, and should encourage strategies aimed at infection prevention or alternative therapies.

1226. Can Universal Decolonization Obviate the Need for Screening and Contact Precautions for Carriers of Methicillin-Resistant Staphylococcus aureus in a Medical Intensive Care Unit With MRSA Endemicity? An Interrupted Time Series Study

BackgroundUniversal decolonization of patients in intensive care units (ICUs) has been identified to be an effective infection control strategy of methicillin-resistant Staphylococcus aureus (MRSA). However, it remains uncertain whether universal decolonization can obviate the need for active surveillance testing (AST) and contact precautions (CPs) for MRSA carriers.MethodsWe conducted an interrupted time series study to evaluate whether universal decolonization (daily chlorhexidine bathing plus twice-daily intranasal mupirocin ointment for 5 days) without AST and CPs did affect the incidence of MRSA acquisition on clinical specimen and MRSA bacteremia (the first positive blood culture obtained more than 48 hours after ICU admission) in a medical ICU. There was a 12-month control period of universal decolonization combined with AST and CPs, followed by a 12-month intervention period of universal decolonization without AST and CPs for MRSA carriers. Changes in incidence density (new cases of MRSA acquisition on clinical specimen per 1,000 eligible patient-days) of MRSA were evaluated by segmented Poisson regression, and the cox proportional-hazards regression model was used to compare the differences in incidence of MRSA bacteremia between the two periods.ResultsThe median overall prevalence of MRSA did not differ between the two periods (25.3% vs. 23.4%, P = 0.55), and the segmented Poisson regression analysis revealed that there were no significant differences in both level and trend of MRSA prevalence (P = 0.43 and P = 0.27, respectively). The incidence density of MRSA acquisition on clinical specimen was lower during the intervention period (5.7 vs. 4.5, P = 0.039). However, both level and trend of MRSA incidence density did not differ significantly whether to perform active surveillance and contact precaution or not (P = 0.94 and P = 0.81, respectively). No patient developed MRSA bacteremia during the control period and there were only two patients of MRSA bacteremia during the intervention period, which showed no significant difference (Log rank test, P = 0.21).ConclusionUniversal decolonization without AST and CPs for MRSA carriers do not increase the incidence of MRSA acquisition on clinical specimen and ICU-attributable MRSA bacteremia in ICU with high prevalence rate of MRSA.Disclosures All authors: No reported disclosures.

Prevalence of Methicillin-resistant Staphylococcus aureus in Abeokuta, Nigeria

This study examined the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) in clinical samples of patients in Abeokuta, Ogun State, Nigeria using standard recommended procedures. A total of 338 clinical specimens of Pus, Aspirate, Ear and Wound swabs were collected from three major health facilities in Abeokuta, Nigeria. Each sample was cultured for bacteria isolates and examined for colonial and cellular morphology while biochemical identification was performed. Of the clinical samples collected, 50.3% were collected from male and highest rate of 37.9% was from age group 0-9 years and least rate of 7.6% was from age 10-19 and 40-49years. Only 32.9% samples were ear swabs, wound swabs (29.2%) and lowest rate of 16.8% for aspirate. Of the 161 Staphylococcus aureus (32.2%) isolated; there was no significant disparity found in relation to the study sites (c2=7.145, p-value = 0.308). The present study indicated a high prevalence rate of MRSA that require empirical and urgent intervention to prevent staphylococcal infection among the hospital patients and its outbreak.

MRSA prevalence rates detected in a tertiary care hospital in Austria and successful treatment of MRSA positive patients applying a decontamination regime with octenidine.

Methicillin-resistant Staphylococcus aureus (MRSA) decontamination regimens predominantly use chlorhexidine bathing in combination with mupirocin nasal ointment. However, resistances in Staphylococcus aureus strains are increasingly common and there is a need of alternative, safe and feasible protocols. This interventional cohort study performed at the Albert Schweitzer Hospital in Graz, Austria, aimed to (1) determine MRSA prevalence at different body sites and (2) assess the efficacy of the decontamination using octenidine-based leave-on products added to existing robust infection control measures. All inpatients of this tertiary care hospital being treated in geriatric medical wards (GWs) and apallic care units (ACUs) were screened for MRSA and decontamination rates were determined after one, two or three decontamination cycles, respectively. At baseline, MRSA was detected in 25 of the 126 patients screened (19.8%). We found MRSA in 13/126 (10.3%) swabs from nasal vestibules, in 12/126 (9.5%) skin swabs, in 11/51 (21.6%) swabs from PEG-stomata or suprapubic catheters and in 8/13 (61.5%) tracheostomata swabs. A maximum of three 5-day decontamination cycles reduced the number of MRSA positive patients by 68.0%. Excluding non-compliant and deceased patients, decontamination reduced MRSA carriage by 93.3% (n=15). No adverse events related to the applied decontamination regimen occurred. Exclusive screening of the nose might underreport MRSA prevalence rates. In this study, decontamination with octenidine-based leave-on products was safe and effective in a critical patient population.

Prevalence of Methicillin‐Resistant Staphylococcus aureus from Equine Nasopharyngeal and Guttural Pouch Wash Samples

BackgroundMethicillin‐resistant Staphylococcus aureus (MRSA) is recognized as a cause of nosocomial infections in both human and veterinary medicine. Studies that examine the nasopharynx and guttural pouches of the horse as carriage sites for MRSA have not been reported.Hypothesis/Objective MRSA colonizes the nasopharynx and guttural pouch of horses. To determine the prevalence of MRSA in equine nasopharyngeal wash (NPW) and guttural pouch lavage (GPL) samples in a field population of horses.SamplesOne hundred seventy‐eight samples (123 NPW and 55 GPL) from 108 horses.MethodsProspective study. Samples were collected from a convenience population of clinically ill horses with suspected Streptococcus equi subsp. equi (S. equi) infection, horses convalescing from a known S. equi infection, and asymptomatic horses undergoing S. equi screening. Samples were submitted for S. aureus aerobic bacterial culture with mannitol salt broth and two selective agars (cefoxitin CHROMagar as the PBP2a inducer and mannitol salt agar with oxacillin). Biochemical identification of Staphylococcus species and pulsed‐field gel electrophoresis (PFGE), to determine clonal relationships between isolates, were performed.ResultsMethicillin‐resistant Staphylococcus (MRS) was isolated from the nasopharynx of 7/108 (4%) horses. Three horses had MRSA (2.7%), and 4 had MR‐Staphylococcus pseudintermedius (MRSP). MRSA was isolated from horses on the same farm. PFGE revealed the 3 MRSA as USA 500 strains.Conclusions and Clinical ImportanceSampling the nasopharynx and guttural pouch of community‐based horses revealed a similarly low prevalence rate of MRSA as other studies sampling the nares of community‐based horses. More study is required to determine the need for sampling multiple anatomic sites when screening horses for MRSA.

Effect of daily chlorhexidine bathing on the acquisition of methicillin-resistant Staphylococcus aureus in a medical intensive care unit with methicillin-resistant S aureus endemicity.

Universal decolonization is recommended in intensive care units (ICUs) that have unacceptably high rates of methicillin-resistant Staphylococcus aureus (MRSA) despite implementation of basic prevention strategies. An interrupted time series study was performed to evaluate the effect of daily chlorhexidine bathing on the acquisition of MRSA in a medical ICU with MRSA endemicity. There was a 14-month control period and a 16-month chlorhexidine bathing period. Segmented Poisson regression analysis was performed to assess the impact of daily chlorhexidine bathing on the incidence density of MRSA. Also, chlorhexidine susceptibility testing with polymerase chain reaction for the qacA/B gene was performed on MRSA isolates collected during the chlorhexidine bathing period. There was a significant reduction in trend (-0.056; 95% confidence interval, -0.095 to -0.017; P = .005) of incidence density of MRSA despite a significant increase in both level and trend of MRSA prevalence rates during the chlorhexidine bathing period. However, there was no significant reduction in level of incidence density of MRSA during the interventional period. Minimum inhibitory concentration of chlorhexidine and the detection rates of the qacA/B gene for a total of 174 MRSA isolates did not increase during the chlorhexidine bathing period. Daily chlorhexidine bathing resulted in a significantly decreasing trend of MRSA acquisition rates irrespective of increased MRSA prevalence rates in the medical ICU. There was no shift of chlorhexidine-resistant MRSA strains.

The Role of Methicillin-Resistant Staphylococcus aureus in Clinical infections in Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, South Western Nigeria

This study determined the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) from 246 clinical samples collected at a tertiary care hospital, its antimicrobial susceptibility, spectrum of infections and the associated risk factors. Standard procedures were used for isolation, screening, and susceptibility testing. The result showed that 41 (40.2%) out of 102 S. aureus isolated were methicillin-resistant while 61 (59.8%) were methicillin-sensitive. The prevalence rate of MRSA for male and female group was 37.3% and 43.1% respectively. Thirty (73.2%) methicillin-resistant S. aureus isolates were obtained from inpatients while 11 (26.8%) were from outpatients. MRSA were significantly isolated from the Orthopaedic ward (OR=3.36; P=0.031) and the antenatal ward (OR=8.33; P=0.037). High resistance rates were exhibited by MRSA isolates to cefotaxime (102, 79.4%) and clindamycin (102, 49%) but had low resistance rates to gentamicin (102, 27.5%) and chloramphenicol (n=102, 28.4%). MRSA were more significantly resistant to gentamicin (χ 2 =12.284; p=0.0001), clindamycin (χ 2 =20.234; p=0.0001) and cefotaxime (χ 2 =13.812; p=0.0002) than MSSA. Thirtytwo (78%) out of 41 MRSA isolated were multidrug resistant. All isolates (MRSA and MSSA) were susceptible to vancomycin with MIC values ranging from 2.1 to 0.12 µg/ml. This study showed a high prevalence of MRSA in clinical infections that were resistant to treatment options in OAUTHC, Ile-Ife. Being in the antenatal and orthopaedic wards is a predictor of MRSA infections in the hospital. In spite of reports that vancomycin resistant Staphylococcus aureus is increasing, it is yet to be a problem in the hospital and vancomycin remains a drug of choice for the treatment of MRSA and multidrug resistant Staphylococcus aureus infections.

Prevalence of Methicillin Resistant Staphylococcus aureus in patients admitted in a Tertiary Care Hospital of North India

Introduction: Methicillin resistant Staphylococcus aureus (MRSA) is endemic in India. In the present era of antibiotic resistance, the emergence of multi-drugs resistant organism is becoming more common. The present study is performed in patients admitted in hospital in various department of hospital to study the infection rate of MRSA from these units. Objectives: The aim of this study was to isolate Staphylococcus aureus from various samples of patients admitted in tertiary care hospital, to study the prevalence rate of MRSA in the hospital. Material and method: The study was conducted in TMMC RC hospital from January 2013 to Sepetember2013. A total of one hundred Staphylococcus aureus isolates from clinical samples were subjected to MRSA screening using Kirby-Bauer methods with cefoxitin 30μg discs per CLSI guidelines. Results: There were 225 different samples collected and all the samples were inoculated on Blood agar medium than incubated. After overnight incubation 100 Staphylococcus aureus were isolated, among which 26 were MRSA and 74 were MSSA has been isolated.The susceptibility pattern of antibiotics showed that all MRSA isolates were significantly less sensitivity to antibiotics as compared to MSSA. None of the MRSA strain showed resistance towards Vancomycin Linezolid. Conclusion: The emergence of MRSA and other antibiotic resistant organisms reflects widespread ubiquitous over-use of antibiotics on a global scale. Control measures are required to prevent spread and reduce emergence of resistance.

Rapid, highly discriminatory binary genotyping to demonstrate methicillin-resistant Staphylococcus aureus transmission in a tertiary care intensive care unit.

No previous studies of methicillin-resistant Staphylococcus aureus (MRSA) epidemiology in adult intensive care units (ICUs) have assessed the utility of rapid, highly discriminatory strain typing in the investigation of transmission events. Observational. A 22-bed medical-surgical adult ICU. Patients Those admissions MRSA-positive on initial screening and all admissions <48 hours in duration were excluded, leaving a cohort of 653 patients (median age, 61 years; APACHE-II, 19). We conducted this study of MRSA transmission over 1 year (August 1, 2011 to July 31, 2012) using a multiplex PCR-based reverse line blot (mPCR/RLB) assay to genotype isolates from surveillance swabs obtained at admission and twice weekly during ICU stays. MRSA prevalence and incidence rates were calculated and transmission events were identified using strain matching. Colonization pressure was calculated daily by summation of all MRSA cases. Of 1,030 admissions to ICU during the study period, 349 patients were excluded. MRSA acquisition occurred during 31 of 681 (4.6%) remaining admissions; 19 of 31(61%) acquisitions were genotype-confirmed, including 7 (37%) due to the most commonly transmitted strain. Moving averages of MRSA patient numbers on the days prior to a documented event were used in a Poisson regression model. A significant association was found between transmission and colonization pressure when the average absolute colonization pressure on the previous day was ≥3 (χ2=7.41, P=0.01). mPCR/RLB characterizes MRSA isolates within a clinically useful time frame for identification of single-source clusters within the ICU. High MRSA colonization pressure (≥3 MRSA-positive patients) on a given day is associated with an increased likelihood of a transmission event.

Prevalence of Methicillin-Resistant Staphylococcus aureus (MRSA) in Raw Meat and Meat Handlers in Onitsha, Nigeria

Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen, causing severe morbidity and mortality worldwide both in hospitals and the community. Recent reports of isolation of methicillin-resistant Staphylococcus aureus (MRSA) from food animals, their meats as well as animal keepers have raised concern about the potential for food borne and zoonotic transmission. This study, evaluated the prevalence of MRSA in meat and meat handlers in Onitsha, Nigeria. A total of 274 samples were collected and analyzed using standard microbiological techniques. Staphylococcus aureus isolates were properly identified using standard procedures and confirmed as methicillin-resistant Staphylococcus aureus using Oxacillin-Resistance Screening Agar Base (ORSAB), supplemented with 2 g/l oxacillin. MRSA prevalence rates of 11(14.3%), 6(85.7%), 4(57.1%) and 12(63.2%) were observed in Beef, Pork, Donkey and Goat meats respectively. There was a significant difference in MRSA prevalence among the meat types (X2= 107.936; P<0.05). The Butchers’ tables showed MRSA prevalence of 3(50%), 8(100%), 2(100%) and 4(100%) for Beef, Goat, Pork and Donkey respectively, while the recovery rates of the organism from cutting knives were 2(33.33%), 7(100%), 2(100%) and 4(100%) for Beef, Goat, Pork and Donkey respectively; no MRSA was recovered from carcass dressing water. Out of 5 MRSA isolates from the body of live cows, 1(20%) was from the nostril, 2(40%) from the ear and 2(40%) from the groin. Over-all, the occurrence of MRSA in butchers was 51%. Out of 29 MRSA isolates from butchers, 12(41.38%) were from butchers 1-10 years in business, 9(31.03%) from 11-20 years, 5(17.24%) from 21-30 years. Two (6.9%) were observed in butchers 31-40 years in business, while 1(3.44%) was from 41-50 years in business. The high prevalence of MRSA in meat and its handlers tends to be of public health concern as it may play a potential role in disseminating the organism between animals and humans as well as to the community. Therefore, proper hygienic practices, control of indiscriminate use of antibiotics, and frequent screening of the risk population for MRSA, are hereby recommended both for prevention and control of meat borne infections and other community-acquired MRSA infections.

Effectiveness of Hospital-Wide Methicillin-Resistant Staphylococcus aureus (MRSA) Infection Control Policies Differs by Ward Specialty

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of preventable nosocomial infections and is endemic in hospitals worldwide. The effectiveness of infection control policies varies significantly across hospital settings. The impact of the hospital context towards the rate of nosocomial MRSA infections and the success of infection control is understudied. We conducted a modelling study to evaluate several infection control policies in surgical, intensive care, and medical ward specialties, each with distinct ward conditions and policies, of a tertiary public hospital in Sydney, Australia. We reconfirm hand hygiene as the most successful policy and find it to be necessary for the success of other policies. Active screening for MRSA, patient isolation in single-bed rooms, and additional staffing were found to be less effective. Across these ward specialties, MRSA transmission risk varied by 13% and reductions in the prevalence and nosocomial incidence rate of MRSA due to infection control policies varied by up to 45%. Different levels of infection control were required to reduce and control nosocomial MRSA infections for each ward specialty. Infection control policies and policy targets should be specific for the ward and context of the hospital. The model we developed is generic and can be calibrated to represent different ward settings and pathogens transmitted between patients indirectly through health care workers. This can aid the timely and cost effective design of synergistic and context specific infection control policies.

Loss of the meca gene during storage of methicillin-resistant Staphylococcus aureus isolates in Northwestern Nigeria

Preservation of strains in a microbiology laboratory is of great importance for quality control, teaching, and research. Freezing is a very common method of preservation and storage of microorganisms. The evaluation of new diagnostic or in vitro antimicrobial susceptibility tests for methicillin-resistant Staphylococcus aureus (MRSA) requires well-defined strain collections. The study was aimed at determining whether loss of mecA gene in MRSA is related to the storage method. A total of 1692 non-duplicate S. aureus isolates were collected from different human clinical specimens at 8 different health institutions in Northwestern Nigeria from February, 2008 to April, 2010. All the isolates were screened for methicillin resistance using disc diffusion method (DDM), screen agar method (SAM) and latex agglutination techniques (PBP). Thereafter, the isolates were stored in 16% v/v glycerol broth at -80°C. In December, 2011, the isolates were retested by polymerase chain reaction (PCR) which was used to amplify both the S. aureus specific sequence gene andmecA gene of 100 isolates, with the amplicon size of 107 and 532 bp. The prevalence rate of MRSA on DDM, SAM, and PBP were 26.3, 24.2 and 25.0%, respectively. Surprisingly, themecA gene was lost in 95.0% of 100 MRSA isolates after 2 years of storage at −80°C with the Micro bank system (Pro-lab Diagnostics, Austin, Tex.). This study demonstrates thatmecA can be lost from MRSA strains stored at −80°C with the Micro bank system. This finding has important implications for the management of strain collections and is of use for all future biobanking projects. Key words: Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA),mecA gene, storage, human, Northwestern Nigeria.

Nasal Carriage of 200 Patients with Nasal Bone Fracture in Korea

BackgroundPathogens in the nasal cavity during nasal surgery could lead to a systemic infectious condition, such as bacteremia, nosocomial infection, or toxic shock syndrome. However, there is no research about the prevalence of nasal carriage in patients with nasal bone fracture.MethodsThis was a prospective, double-blind, randomized study about the rate of nasal carriage in 200 patients with nasal bone fracture in Korea. Nasal secretions were taken from both the middle nasal meatus and colonized. All analyses were carried out using SPSS software.ResultsPathogens were identified in 178 of the 200 cases. Coagulase-negative staphylococci (CNS) were the most cultured bacteria in 127 (66.84%) of the 190 total patients after excluding 10 cases of contaminated samples, and methicillin-resistant coagulase-negative staphylococci (MRCNS) were found in 48 (25.26%). Staphylococcus aureus was the second most identified pathogen, found in 36 (18.95%), followed by 7 cases (3.68%) of methicillin-resistant Staphylococcus aureus (MRSA). The prevalence rate of MRSA in the females was higher than that in the males (RR=4.70; 95% CI, 1.09-20.18), but other demographic factors had no effect on the prevalence rate of MRSA and MRCNS.ConclusionsThe prevalence rate of these pathogens in patients with nasal bone fracture in Korea was similar to other reports. However, few studies have addressed the prevalence rate of CNS and MRCNS in accordance with risk factors or the change in prevalence according to specific prophylaxis against infectious complications. Additional research is needed on the potential connections between clinical factors and microbiological data.

Epidemiology of multidrug-resistant microorganisms among nursing home residents in Belgium.

ObjectivesA national survey was conducted to determine the prevalence and risk factors of methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamases-producing Enterobacteriaceae (ESBLE) and vancomycin-resistant enterococci (VRE) among nursing home residents in Belgium.MethodsA random stratified, national prevalence survey was conducted in nursing home residents who were screened for carriage of ESBLE, MRSA and VRE by multisite enriched culture. Characteristics of nursing homes and residents were collected by a questionnaire survey and were analysed by multilevel logistic regression analysis.ResultsOf 2791 screened residents in 60 participating nursing home, the weighted prevalence of ESBLE and MRSA carriage were 6.2% (range: 0 to 20%) and 12.2% (range: 0 to 36%), respectively. No cases of VRE were found. No relationship was found between ESBLE and MRSA prevalence rates within nursing homes and the rate of co-colonization was very low (0.8%). Geographical variations in prevalence of MRSA and ESBLE and in distribution of ESBL types in nursing home residents paralleled that of acute hospitals. Risk factors of ESBLE carriage included previously known ESBLE carriage, male gender, a low level of mobility and previous antibiotic exposure. Risk factors for MRSA colonization were: previously known MRSA carriage, skin lesions, a low functional status and antacid use.ConclusionsA low prevalence of ESBLE carriage was found in nursing home residents in Belgium. The prevalence of MRSA carriage decreased substantially in comparison to a similar survey conducted in 2005. A low functional status appeared as a common factor for ESBLE and MRSA carriage. Previous exposure to antibiotics was a strong predictor of ESBLE colonization while increased clustering of MRSA carriage suggested the importance of cross-transmission within nursing homes for this organism. These results emphasize the need for global coordination of the surveillance of MDRO within and between nursing homes and hospitals.