Methicillin-resistant Staphylococcus Aureus Cases Research Articles

Clinical characteristics and therapeutic outcomes of hematogenous vertebral osteomyelitis caused by methicillin-resistant Staphylococcus aureus

To evaluate the clinical characteristics and therapeutic outcomes of patients with hematogenous vertebral osteomyelitis (HVO) caused by methicillin-resistant Staphylococcus aureus (MRSA). We performed a cohort study of adult patients diagnosed with S. aureus HVO at a tertiary-care hospital over a 7-year period. Of the 139 patients with S. aureus HVO, MRSA caused 62 (44.6%) cases. In multivariate analysis, compared with methicillin-susceptible S. aureus (MSSA), MRSA was associated with a higher risk of persistent bacteremia (≥7 days) (8.40 fold; P<0.001) and relapse (4.83 fold; P=0.03), and increased hospital stay (1.69 fold; P=0.001). Among the MRSA cases, relapse rates differed according to duration of antibiotics: 41.7% (4-6 weeks), 25.0% (6-8 weeks), and 5.6% (≥8 weeks) (P=0.007). Bacteremia was more likely to persist for ≥7 days in patients with an initial vancomycin trough <15mg/L than in those with an initial trough ≥15mg/L (79.3% vs. 20.0%; P=0.001). MRSA HVO was associated with more frequent persistent bacteremia (≥7 days) and relapse, and longer hospital stay compared to MSSA HVO. Antibiotic therapy for ≥8 weeks and targeting a vancomycin trough of ≥15mg/L may be benefit patients with MRSA HVO.

Successful reduction of hospital-acquired methicillin-resistant Staphylococcus aureus in a urology ward: a 10-year study.

BackgroundTo eradicate hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) using a stepwise infection control strategy that includes an avoidance of antimicrobial prophylaxis (AMP) based on surgical wound classification and an improvement in operative procedures in gasless single-port urologic surgery.MethodsThe study was conducted at an 801-bed university hospital. Since 2001, in the urology ward, we have introduced the stepwise infection control strategy. In 2007, surveillance cultures for MRSA in all urological patients were commenced. The annual incidence of MRSA was calculated as a total number of newly identified MRSA cases per 1,000 patient days. Trend analysis was performed using a Poisson regression.ResultsOver the study period, 139,866 patients, including 10,201 urology patients, were admitted to our hospital. Of these patients, 3,719 patients, including 134 ones in the urology ward, were diagnosed with MRSA throughout the entire hospital. Although the incidence of MRSA increased throughout the entire hospital (p = 0.002), it decreased significantly in the urology ward (p < 0.0001). Of the 134 cases, 45 (33.6%) were classified as “imported,” and 89 (66.4%) as “acquired.” In the urology ward, the incidence of acquired MRSA decreased significantly over time (p < 0.0001), whereas the incidence of imported MRSA did not change over time (p = 0.66). A significant decrease (p < 0.0001) in the incidence of clinically significant MRSA infection over time was found.ConclusionsStepwise infection control strategy that includes a reduction or avoidance of antimicrobial prophylaxis in minimally invasive surgery can contribute to a reduction in hospital-acquired MRSA.Trial registrationCurrent study has approved by the institutional ethical review board (No.1141).

Trends in ophthalmic manifestations of methicillin-resistant Staphylococcus aureus (MRSA) in a northern California pediatric population

To determine pediatric clinical trends of ocular and periocular methicillin-resistant Staphylococcus aureus (MRSA) in a large northern California healthcare system. This study was a retrospective cross-sectional review of all pediatric cases (aged 0-18) with culture-positive ophthalmic MRSA isolates identified between January 2002 and December 2009. Medical record review included history, presentation, infection site, acquisition (community or nosocomial), antibiotic sensitivity/resistance, treatment, and clinical outcome. Incidence was classified by year, sex, and age. Parameters were analyzed for statistical significance by trend and χ(2) analysis. A total of 399 ocular and periocular MRSA cases were included. Cases trended upward from 2002 to 2009, peaking in 2006. Of the 137 pediatric cases (0-18 years), 58% were community acquired. Conjunctivitis was the predominant presentation (40%), followed by stye/chalazion (25%), orbital cellulitis/abscess (19%), dacryocystitis (11%) and brow abscess (3%). Significant predictors for ocular infection with MRSA included male sex (61%), neonates (38%), and multiple infection sites on the body (38%). Resistance was high to bacitracin (80.9%) and ofloxacin (48.3%) but remained low for trimethoprim/sulfamethoxazole (8.7%). Topical therapy was effective in 29% of cases; oral antibiotics, in 47%. Intravenous therapy was required in 12% of cases and incision/drainage or surgery in 19%. Initial oral antibiotic treatment, primarily cephalosporins (24%), was ineffective in 37% of patients. There was a significant increase in resistance to antibiotic therapy (P < 0.001) during the study period. No patients developed permanent visual impairment. Pediatric ocular and periocular MRSA is increasing in incidence and resistance in our patient population. Outcomes can be improved by early recognition, proper antibiotic selection, and obtaining cultures and sensitivities when resistant or severe ocular infections are present.

Infections With Pseudomonas Aeruginosa in Charcot Arthropathy of the Foot

Patients with Charcot arthropathy present a high risk for ulcers with secondary bone infection. Infections with Pseudomonas aeruginosa represent a severe threat to the patients. We hypothesized that infections with P aeruginosa result in a longer stay in hospital and more operations than infections with other bacteria. All patients who underwent surgery for Charcot arthropathy of the feet between 1996 and 2006 (n = 205) in our clinic were included. The duration of hospitalization and number of surgeries for infections due to methicillin-resistant Staphylococcus aureus (MRSA) versus P aeruginosa were compared to infections with other bacteria. All patients were scanned for MRSA and were isolated when tested positive and treated according to a defined algorithm. Seventy-nine intraoperative samples exhibited bacterial growth: 12 cases of MRSA, 14 cases of P aeruginosa, and 53 case of other bacteria. Patients with deep infections due to P aeruginosa stayed significantly longer in the hospital (52 vs 35 days, P < .041) and needed significantly more surgery (1.71 vs 1.28 surgeries, P < .027). There was no significant difference between patients with MRSA infections and those without MRSA or P aeruginosa. Infections with P aeruginosa resulted in more surgeries and a longer stay in the hospital. Early debridement is the basic treatment. A specific algorithm for isolation and operative and antibiotic treatment for P aeruginosa infections is proposed similar to an algorithm for MRSA that has been shown to be successful. Level IV, retrospective case Series.

Household risk factors for colonization with multidrug-resistant Staphylococcus aureus isolates.

Antimicrobial resistance, particularly in pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), limits treatment options and increases healthcare costs. To understand patient risk factors, including household and animal contact, potentially associated with colonization with multidrug-resistant MRSA isolates, we performed a prospective study of case patients colonized with MRSA on admission to a rural tertiary care hospital. Patients were interviewed and antimicrobial resistance patterns were tested among isolates from admitted patients colonized with MRSA in 2009–10. Prevalence of resistance was compared by case-patient risk factors and length-of-stay outcome among 88 MRSA case patients. Results were compared to NHANES 2003–04. Overall prevalence of multidrug resistance (non-susceptibility to ≥four antimicrobial classes) in MRSA nasal isolates was high (73%) and was associated with a 1.5-day increase in subsequent length of stay (p = 0.008). History of hospitalization within the past six months, but not antimicrobial use in the same time period, was associated with resistance patterns. Within a subset of working-age case patients without recent history of hospitalization, animal contact was potentially associated with multidrug resistance. History of hospitalization, older age, and small household size were associated with multidrug resistance in NHANES data. In conclusion, recent hospitalization of case patients was predictive of antimicrobial resistance in MRSA isolates, but novel risk factors associated with the household may be emerging in CA-MRSA case patients. Understanding drivers of antimicrobial resistance in MRSA isolates is important to hospital infection control efforts, relevant to patient outcomes and to indicators of the economic burden of antimicrobial resistance.

Epidemiology of methicillin-resistant Staphylococcus aureus carrying the novel mecC gene in Denmark corroborates a zoonotic reservoir with transmission to humans

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated (HA), community-associated (CA) and live-stock-associated (LA) infections. Recently, the discovery of human and bovine MRSA isolates carrying a new mecA gene homologue, mecALGA251 (now designated mecC), has caused concern because they are not detected by conventional, confirmatory tests for MRSA. Very little is known about their frequency, epidemiology and possible transmission between livestock and humans. In this study, the epidemiology of the mecC isolates in Denmark was investigated by screening the national collections of MRSA cases (from 1988 onwards) and S. aureus bacteraemia cases (from 1958 onwards). Isolates carrying mecC were only recovered infrequently before 2003 (n = 2) but now seem to be increasing, with 110 cases in 2003–2011. Clinical data on mecC-carrying MRSA demonstrated that mecC-MRSA were primarily community-acquired (CA-MRSA) and affected persons typically living in rural areas, being older than other CA-MRSA patients. Among 22 cases in Region Zealand, four reported contact with cattle and sheep. Two of these persons lived on farms with livestock positive for mecC-carrying MRSA, sharing spa type (t843), MLVA (MT429) and PFGE pattern with the human isolates. These observations indicate that mecC-carrying MRSA can be exchanged between humans and ruminants.

Characterization of methicillin-resistant Staphylococcus aureus from skin and soft tissue infections in patients in Nairobi, Kenya

Skin and soft tissue infections (SSTIs) are among the most common infectious diseases and a frequent cause of hospital visits. In this study we sought to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and antibiotic susceptibility patterns in SSTIs in patients attending hospitals in Kenya. Eighty-two S. aureus isolates recovered from SSTIs from both inpatients and outpatients were screened for antibiotic susceptibility, possession of staphylococcal cassette chromosome mec (SCCmec) gene type, and the Panton-Valentine leukocidin (PVL) toxin gene. The prevalence of MRSA was investigated in relation to the type of patient and infection type, as well as the type of health care facility. Of 60 boil cultures, 39 (65%) grew S. aureus, of out of which 34 (87.2%) were MRSA. Of the 60 abscess cultures, 14 (23.3%) grew S. aureus, of which 10 (71.4%) were MRSA. Of 34 cellulitis cultures, 18 (52.9%) grew S. aureus, of which 16 (88.8%) were MRSA. Of 25 ulcer cultures, 11 (44%) grew S. aureus, of which nine (81.8%) were MRSA. Sixty-nine of 82 S. aureus (84.1%) were MRSA, with 52 (75.4%) possessing SCCmec II type and 14 (20.3%) being positive for the PVL gene. Based on hospitals, it was noted that most MRSA were isolated at publicly funded health care facilities serving an economically disadvantaged segment of Nairobi's population, such as those living in urban informal settlements. All 82 S. aureus were susceptible to vancomycin and resistant in high numbers to macrolides, aminoglycosides, and quinolones. Bacterial isolates were mostly susceptible to vancomycin, ciprofloxacin and co-trimoxazole, and none was resistant to vancomycin. However, most organisms showed decreased susceptibility to erythromycin and clindamycin. These findings suggest that SCCmec II MRSA and a PVL strain of MRSA are significant pathogens in patients with SSTIs presenting to hospitals in Kenya, and that MRSA cases are prevalent at publicly funded health care facilities.

Readmission of known MRSA carriers and MRSA colonization pressure in hospital.

Readmission of asymptomatic methicillin-resistant Staphylococcus aureus (MRSA) carriers may contribute to the hospital reservoir. Using an electronic alert system, we assessed the weight of readmission of known MRSA carriers on MRSA colonization pressure in a hospital setting. During the 2004-2010 period, 2058 alerts were generated for 1060 inpatients. A total of 486/1060 patients (46%) were readmitted at least once, and 330/486 (64·4%) were readmitted <3 months after discharge. A mean of 20 MRSA patients were present on the same day (from 40 in 2004 to eight in 2010). The number of MRSA patient-days was 34 575, i.e. 2·5% of the 1 366 277 patient-days of the study period, and 17 737 (51·3%) MRSA patient-days were due to readmission of known MRSA carriers. The number of new MRSA cases was partly correlated with the number of MRSA patients hospitalized (R 2 = 0·49). Rapid electronic identification of these patients proved essential in decreasing the global burden of MRSA in our hospital.

A population-based study of the epidemiology and clinical features of methicillin-resistant Staphylococcus aureus infection in Pennsylvania, 2001–2010

No U.S. general population-based study has characterized the epidemiology and risk factors, including skin and soft tissue infection (SSTI), for healthcare-associated (HA) and community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA). We estimated the incidence of HA- and CA-MRSA and SSTI over a 9-year period using electronic health record data from the Geisinger Clinic in Pennsylvania. MRSA cases were frequency-matched to SSTI cases and controls in a nested case-control analysis. Logistic regression was used to assess risk factors, while accounting for antibiotic administration. We identified 1713 incident CA- and 1506 HA-MRSA cases and 78 216 SSTI cases. On average, from 2005 to 2009, the annual incidence of CA-MRSA increased by 34%, HA-MRSA by 7%, and SSTI by 4%. Age, season, community socioeconomic deprivation, obesity, smoking, previous SSTI, and antibiotic administration were identified as independent risk factors for CA-MRSA.

Methicillin-resistant Staphylococcus aureus (MRSA) in an Austrian urological department: 10 years experience covering 95.161 patients

So far, few data is available on Methicillin-resistant Staphylococcus aureus (MRSA) infections in urology. To obtain a better insight into MRSA infections, we studied prevalence, colonization and infection site and clinical implications of MRSA in a urological department over a 10-year period. A retrospective study of all patients diagnosed with MRSA for the first time over a 10-year period was set-up. Between 2000 and 2009, a total of 95.161 in- and outpatients were seen at our department. The prevalence of patients with newly diagnosed MRSA was low, that is, <0.1 % per year (mean 0.07%, 0.02-0.1 %). In total, 62 MRSA cases were identified over a 10-year period. MRSA incidence was 10 times higher in inpatients (0.2 %) than in outpatients (0.02 %). Asymptomatic MRSA colonization was present in 25/62 patients (40.3 %), the remaining 59.7 % (37/62) showed clinical symptoms: MRSA positive swabs from open wounds were seen in 10/62 patients (16.1 %). Urinary tract infections were seen in 26/10 patients (41.9 %), while life-threatening MRSA sepsis occurred in one patient only over a decade. In summary, we observed very low rates of MRSA colonization and infection. Still, complications like delayed wound healing, development of abscess and even sepsis may occur.

A Collaborative, Systems-Level Approach to Eliminating Healthcare-Associated MRSA, Central-Line–Associated Bloodstream Infections, Ventilator-Associated Pneumonia, and Respiratory Virus Infections

To achieve sustainable reductions in healthcare-associated infections (HAIs), the University of Washington Medical Center (UWMC) deployed a collaborative, systems-level initiative. With the sponsorship of senior leadership, multidisciplinary teams were established to address healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA), central-line-associated bloodstream infections (CLABSI), ventilator-associated pneumonia (VAP), and respiratory virus infections. The goal of the initiative was to eliminate these four HAIs among medical center inpatients by 2012. In the first 24 months of the project, the number of healthcare-associated MRSA cases decreased 58%; CLABSI cases decreased 54%. Staff and provider compliance with infection prevention measures improved and remained strong, for example, 96% compliance with hand hygiene, 98% compliance with the recommended influenza vaccination program, and 100% compliance with the VAP bundle. Achieving these results required an array of coordinated, systems-level interventions. Critical project success factors were believed to include creating organizational alignment by declaring eliminating HAIs as an organizational breakthrough goal, having the organization's executive leadership highly engaged in the project, coordination by an experienced and effective project leader and manager, collaboration by multidisciplinary project teams, and promoting transparency of results across the organization.

Epidemiologic Similarities in Pediatric Community-Associated Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus in the San Francisco Bay Area

Risk factors differentiating methicillin-resistant Staphylococcus aureus (MRSA) from methicillin-sensitive S aureus (MSSA) infections in the pediatric community have been unclear. We performed a prospective case-comparison investigation of clinical, epidemiological, and molecular factors in pediatric community-associated (CA) MRSA and MSSA cases in the San Francisco Bay Area. Chart reviews were conducted in 270 CA-MRSA and 313 CA-MSSA cases. Fifty-eight CA-MRSA (21.4%) and 95 CA-MSSA (30.4%) cases were interviewed. Molecular typing was performed on 111 isolates. MSSA represented 53.7% of CA cases and was more likely to cause invasive disease (6.2% vs 1.1%, P=.004). Few potential epidemiologic risk factors distinguished CA-MRSA from CA-MSSA. No differences were found in factors related to crowding, cleanliness, or prior antibiotic use. Compromised skin integrity due to eczema (24.3% vs 13.5%, P=.001) was associated with CA-MSSA. Many exposures to potentially infected or colonized contacts or contaminated objects were assessed; only three were associated with CA-MSSA: having a household contact who had surgery in the past year (18.9% vs 6.0%, P=.02), and regular visits to a public shower (9.1% vs 2.0%, P=.01) or gym (12.6% vs 3.3%, P=.04). Molecular typing identified clonal complex 8 as the predominant genetic lineage among CA-MRSA (96.4%) and CA-MSSA (39.3%) isolates. In the context of recent heightened focus on CA-MRSA, the burden of serious disease caused by CA-MSSA among children should not be overlooked. MRSA and MSSA may be growing epidemiologically similar; thus, research, clinical, and public health efforts should focus on S aureus as a single entity.

Economic Consequences of the Demography of MRSA Patients and the Impact of Broad-Spectrum Antimicrobials

Studies have determined the societal impact of methicillin-resistant Staphylococcus aureus (MRSA) by modelling its impact on labour supply and productivity. In addition, most of the studies on the topic conclude that the problem of resistance should be counteracted on the macro level by reducing overall antibacterial consumption. Two major questions have been raised in the present work. Firstly, is MRSA impairing labour supply and productivity? Secondly, is it the overall use of antibacterials that may be seen as crucial to the spread of MRSA infections? The age distribution of MRSA patients is compared with the age distribution of the entire patient population at a German teaching hospital. In addition, the age distribution of MRSA patients was applied to the age distribution of the German population in the year 2050 in order to identify the effects of the double-ageing process on the spread of MRSA. Furthermore, recent epidemiological studies were reviewed on the impact of overall antibacterial consumption on MRSA infection rates. Based on available data, we show that patients infected or colonized with MRSA are, for the most part, beyond retirement age and thus not responsible for changes in labour supply or productivity. Application of age distribution of MRSA patients to the age distribution of the German population in the year 2050 gives a 24% increase in the number of MRSA cases to a total of 182 778 due to an ageing population. In addition, we show that a 32% reduction in the cost of MRSA to the German healthcare system could be reached if use of fluoroquinolones and third-generation cephalosporins was reduced by just 10% and, correspondingly, use of antiseptics for hand disinfection was increased by 10%. MRSA is a phenomenon that, to a larger degree, affects the elderly population rather than the labour force. When it comes to policy options to counteract MRSA on the macro level, most economic research on the topic is biased in assuming that the overall use of antibacterials is responsible for the spread of MRSA infections.

Surveillance of methicillin-resistant Staphylococcus aureus (MRSA) in acute care hospitals. Results of the VINCat Program (2008–2010)

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of healthcare-related infection. Surveillance and prevention of MRSA is a priority in infection control programs. The aim of this study was to describe rates and trends of MRSA colonization or infection in 40 hospitals participating in the VINCat Program from 2008 to 2010.The study included all patients treated in acute care areas of participating hospitals. Hospitals were stratified into 3 groups based on size. The following annual indicators were reported: Methicillin-resistance rate, incidence density of new cases of MRSA and incidence density of MRSA bacteremia.Between 2008 and 2010, the yearly mean rate of resistance to methicillin remained stable for the study period (24%–25%), while the mean incidence of new cases of MRSA decreased from 0.65 to 0.54 cases per 1000 patient-days (p=NS) and the mean incidence of MRSA bacteremia decreased from 0.06 to 0.05 cases per 1,000 patient-days (p=NS).The implementation of a MRSA surveillance system in hospitals that participated in the VINCat Program provides information on the situation of each institution and facilitated interhospital comparisons in order to establish appropriate preventive measures.

Transmission rates, screening methods and costs of MRSA—a systematic literature review related to the prevalence in Germany

Methicillin-resistant Staphylococcus aureus (MRSA) infections represent a serious challenge for health care institutions, which is inherent in the combination of prevalence, transmission rates and costs. Furthermore, performing an MRSA screening requires information on the complex system of effectiveness, accuracy and costs of different screening methods. The purpose of this study was to give an overview of parameters with decisive significance for the burden of MRSA and the selection of a specific MRSA screening strategy. A systematic literature search for peer-reviewed health economic studies associated with MRSA was performed (from 1995 to the present). Eighty-seven different studies met all inclusion and exclusion criteria. Primary outcomes included the prevalence of MRSA, MRSA transmission rates, performance characteristics of MRSA screening methods, costs for pre-emptive isolation precautions and costs per MRSA case. The prevalence rates reported for all inpatients (1.2-5.3 %) as well as for inpatients with risk factors or patients in risk areas (3.85-20.6 %) vary greatly. The range of cross-transmission rates per day reported for patients with MRSA in isolation is 0.00081-0.009 and for carriers not in isolation is 0.00137-0.140, respectively. For polymerase chain reaction (PCR) methods, the mean sensitivity and specificity were 91.09 and 95.79 %, respectively. Culture methods show an average sensitivity of 89.01 % and an average specificity of 93.21 %. The turn-around time for PCR methods averages 15 h, while for the culture method, it can only be estimated as 48-72 h. This review filtered important parameters and cost drivers, and covered them with literature-based averages. These findings serve as an ideal evidence base for further health economic considerations of the cost-effectiveness of different MRSA screening methods.

Rapid detection, differentiation and typing of methicillin-resistant Staphylococcus aureus harbouring either mecA or the new mecA homologue mecALGA251

The recent finding of a new mecA homologue, mecALGA251, with only 70% nucleotide homology to the conventional mecA gene has brought the routine testing for mecA as a confirmatory test for methicillin-resistant Staphylococcus aureus (MRSA) into question. A multiplex PCR was designed to differentiate mecALGA251 from the known mecA together with detection of lukF-PV and the spa gene fragments, enabling direct spa typing by sequencing of the PCR amplicons. The PCR analysis and subsequent spa typing were validated on a large collection (n = 185) of contemporary MRSA and methicillin-sensitive S. aureus isolates, including 127 isolates carrying mecALGA251. The mecALGA251 gene was situated in staphylococcal cassette chromosome mec type XI elements, and sequence variation within a 631-bp fragment of mecALGA251 in 79 isolates indicated a very conserved gene sequence. Following a successful validation, the multiplex PCR strategy was implemented in the routine testing of MRSA for national surveillance. Over a 2-month period, among 203 samples tested, 12 new MRSA cases caused by isolates carrying mecALGA251 were identified, emphasizing the clinical importance of testing for these new MRSA isolates.

Infection prevention and control interventions in the first outbreak of methicillin-resistant Staphylococcus aureus infections in an equine hospital in Sweden.

BackgroundThe first outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in horses in Sweden occurred in 2008 at the University Animal Hospital and highlighted the need for improved infection prevention and control. The present study describes interventions and infection prevention control in an equine hospital setting July 2008 - April 2010.MethodThis descriptive study of interventions is based on examination of policy documents, medical records, notes from meetings and cost estimates. MRSA cases were identified through clinical sampling and telephone enquiries about horses post-surgery. Prospective sampling in the hospital environment with culture for MRSA and genotyping of isolates by spa-typing and pulsed-field gel electrophoresis (PFGE) were performed.ResultsInterventions focused on interruption of indirect contact spread of MRSA between horses via staff and equipment and included: Temporary suspension of elective surgery; and identification and isolation of MRSA-infected horses; collaboration was initiated between authorities in animal and human public health, human medicine infection control and the veterinary hospital; extensive cleaning and disinfection was performed; basic hygiene and cleaning policies, staff training, equipment modification and interior renovation were implemented over seven months.Ten (11%) of 92 surfaces sampled between July 2008 and April 2010 tested positive for MRSA spa-type 011, seven of which were from the first of nine sampling occasions. PFGE typing showed the isolates to be the outbreak strain (9 of 10) or a closely related strain. Two new cases of MRSA infection occurred 14 and 19 months later, but had no proven connections to the outbreak cases.ConclusionsCollaboration between relevant authorities and the veterinary hospital and formation of an infection control committee with an executive working group were required to move the intervention process forward. Support from hospital management and the dedication of staff were essential for the development and implementation of new, improved routines. Demonstration of the outbreak strain in the environment was useful for interventions such as improvement of cleaning routines and interior design, and increased compliance with basic hygienic precautions. The interventions led to a reduction in MRSA-positive samples and the outbreak was considered curbed as no new cases occurred for over a year.

Inclusion of 30-Day Postdischarge Detection Triples the Incidence of Hospital-Onset Methicillin-Resistant Staphylococcus aureus

Hospitalized patients are at increased risk for acquisition of methicillin-resistant Staphylococcus aureus (MRSA). As hospital length of stay shortens, hospital-acquired MRSA events may be more likely to be detected after discharge. We assessed the impact of attributing MRSA cases discovered within 30 days after discharge to the most recent hospitalization and identified patient characteristics associated with MRSA detection after discharge. Retrospective cohort study. Twenty-seven acute care hospitals in Orange County, California. Adult acute care admissions (2002-2007). Using a countywide hospital data set containing diagnostic codes with present-on-admission (POA) indicators, we identified the first admission with a MRSA code for each patient. This incident MRSA admission was defined as predischarge-detected (pre-DD) hospital-onset MRSA (HO-MRSA) when MRSA was not POA. If MRSA was POA and a prior admission occurred within 30 days, this prior admission was assigned postdischarge-detected (post-DD) HO-MRSA. We evaluated the impact of including post-DD HO-MRSA in the calculation of hospital HO-MRSA incidence using signed-rank tests and reviewed changes in hospital rankings. We conducted multivariate comparisons of patient characteristics of pre-DD versus post-DD HO-MRSA patients. Among 1,217,253 at-risk hospitalizations, the inclusion of post-DD HO-MRSA tripled the median hospital HO-MRSA incidence, from 12.2 to 35.7 cases per 10,000 at-risk admissions (P < .0001). Hospital ranking changed substantially when including post-DD HO-MRSA. Patients with shorter stays were more likely to have post-DD MRSA. On the basis of administrative claims data, the inclusion of post-DD HO-MRSA significantly increased the estimated HO-MRSA incidence and altered hospital rankings. This finding underscores the limitations of single-facility data when deriving HO-MRSA incidence and rank.

Methicillin-ResistantStaphylococcus aureusInfections in Human Immunodeficiency Virus-Infected Children and Adolescents

Background. Methicillin-resistant Staphylococcus aureus (MRSA) infection incidence has increased in healthy US children. Our objective was to evaluate MRSA incidence and correlates in HIV-infected youth. Methods. The CDC-sponsored LEGACY study is a US multicenter chart abstraction study of HIV-infected youth. We identified MRSA infections among participants with ≥1 visit during 2006. We used bivariate and multivariable analyses to compare sociodemographic and HIV clinical factors between MRSA cases and noncases. Results. Fourteen MRSA infections (1 invasive, 12 soft tissue, 1 indeterminate) occurred among 1,813 subjects (11.1 infections/1,000 patient-years (PY), 95% CI: 11.06–11.14). Most (86%) isolates were clindamycin susceptible. Compared with noncases, MRSA cases were more likely older (17 versus 14 years), black (100% versus 69%), behaviorally HIV infected (43% versus 17%), and in Maryland (43% versus 7%) and had viral loads (VL) >1000 copies/mL (86% versus 51%) and lower mean CD4% (18% versus 27%) (all P < 0.05). In multivariate analysis, independent risk factors were Maryland care site (adjusted odds ratio (aOR) = 9.0), VL >1000 copies/mL (aOR = 5.9), and black race (aOR undefined). Conclusions. MRSA occurred at a rate of 11.1 infections/1,000 PY in HIV-infected youth but invasive disease was uncommon. Geographic location, black race, and increased VL, but not immunosuppression, were independently associated with MRSA risk.

Community-Acquired Methicillin-Resistant Staphylococcus aureus Hand Infections in the Pediatric Population

Recent studies have reported rates of methicillin-resistant Staphylococcus aureus (MRSA) hand infections in patients without risk factors ranging from 26% to 73%. The purpose of our study was to review a large series of pediatric hand infections to determine the rate of MRSA and identify potential risk factors. A retrospective review was performed on patients younger than 15 who were seen for hand infections (2001-2010). Patients were categorized according to medical problems, need for operation, abscess location, and mechanism of injury. Potential MRSA risk factors were assessed using a multivariate-regression model. During the 10-year period, 415 patients were seen for hand infections. A total of 146 patients met the inclusion criteria: patients younger than 15 years of age who presented to the plastic surgery service requiring consultation for hand infections. The overall prevalence of MRSA-positive cultures was found to be 30%. The prevalence of MRSA was 29% in healthy patients and 0% in immunocompromised patients. The prevalence of MRSA increased in a linear fashion from patients without documentation of incision and drainage procedures to patients adequately treated with bedside incision and drainage to patients who required surgical drainage. There was a trend toward a higher prevalence of MRSA in deep space abscesses compared to other abscesses. Patients with a history of trauma and previous MRSA infections had a higher rate of MRSA than other patients. Traditionally, MRSA has been associated with hospitalization, intravenous drug use, recent antibiotic use, and compromised immunity. In our study, more severe, deep-space abscesses requiring surgical drainage and patients with a history of previous MRSA infections were found to have a higher prevalence of MRSA. The immunocompromised patients had no cases of MRSA and had higher incidences of less virulent bacterial infections. This suggests that acquisition of community-acquired MRSA skin and soft tissue infections in children and adolescents might not be associated with the traditional risk factors. Prognostic IV.