MRSA Infection In Patients Research Articles

741. Assessing the Concordance of MRSA Carriage Screening with MRSA Infections

Abstract Background There is a lack of research on MRSA surveillance in children. This study focused on children with confirmed MRSA infections to determine the utility of MRSA screens in guiding empiric anti-MRSA treatment for children without history of MRSA infection. We examined the concordance of screens to assess for differences by infection type, and used statistical analysis to determine significant contributors to concordance. Methods Pediatric hospital patients admitted from 2002-2022 were included. Subjects had MRSA infections subsequent to a MRSA surveillance screen performed in the preceding year. Statistical analysis, namely multivariable and binomial regression, identified associations between MRSA screens and infections. Number needed to treat analysis calculated the utility of re-screening. Results Among 246 subjects, 39.0% had concordant screens. 151 (61.4%) screens were obtained in the two weeks preceding infection. Sensitivity for bacteremia was 50.0% (n=42), for ET/respiratory 44.4% (n=81), for SSTI 29.4% (n=102). For children under 6 months of age, sensitivity was 35.9% (n=78). Multivariable analysis significantly associated days since MRSA screening and decreasing likelihood of concordance. Binomial regression modeled the probability of concordance to drop below 50.0% for all infections after four days, after six days for bacteremia specifically, and twelve days for ET/respiratory infections. Probability of Concordance Over Time The probability of MRSA screening concordance over time based upon binomial prediction modeling. Each line represents the probability of concordance on a given day subsequent to MRSA screening. Number Needed to Treat (test) Analysis A theoretical control arm of patients receiving no re-screening is compared to a theoretical treatment arm receiving re-screening. Each column represents the number needed to re-screen (for a given number of days) to predict one MRSA infection. Absolute risk reduction is overlaid. Conclusion The concordance of screens was far lower than NPV found in past studies. Bacteremia concorded at 50.0%, ET/respiratory infections 44.4%, SSTI 29.4%. The number of days elapsed since MRSA screening proved the only significant covariate. When that covariate modeled the probability of screening concordance with infection, 7 days represented when the probability of concordance fell to or dropped below 50.0% for infection types. Only patients with a known MRSA infection were included in our study, and concordance of screens was far lower than NPV found in past studies; previous results may have been impacted by low prevalence to inform high NPV. We suggest that negative MRSA screens should not invalidate reasonable suspicion for MRSA infection in patients with high pre-test probabilities for infection. Re-screening patients may optimize concordance. Disclosures All Authors: No reported disclosures

Not a wild goose chase: long-lasting MRSA negative status following eradication therapy for chronic MRSA infection in patients with cystic fibrosis

ABSTRACT Objectives Prevalence of MRSA in patients with CF has risen over the past decades, and chronic infection with MRSA is associated with worse outcome in this patient group. Methods This retrospective observational study investigated long-term eradication rate in pediatric and adult CF patients with chronic MRSA infection, using a 6-month eradication regimen containing 2 oral antibiotics, combined with topical decolonisation measures. Respiratory tract cultures were performed at least every three months, from the first MRSA-positive culture onwards. Results A total of 24 patients with chronic MRSA infection were identified from our CF patient registry, of which 13 patients underwent an eradication attempt. The regimen consisted of 2 oral antibiotics: a combination of rifampicin, fusidic acid, clindamycin and co-trimoxazol, based on the sensitivity pattern of the MRSA strain. At the end of the study period (median 8.2 years), 12 out of 13 patients (92%) were MRSA negative. None of the patients interrupted treatment due to side-effects. Conclusions Eradication of chronic MRSA infection is feasible, well-tolerated and highly successful, and can offer a long-lasting MRSA-negative status, obviating the need for patient segregation.

865. Methicillin-resistant Staphylococcus aureus (MRSA) prevalence among healthcare workers (HCW) in contact tracings in a Dutch teaching hospital, 2010-2018

BackgroundIn The Netherlands, the national guidelines on MRSA prevention and control advocate screening of HCW after unprotected exposure to MRSA carriers. Although this strategy at large is successful, contact tracing of staff is a time consuming and costly component. We evaluated our contact tracing policy for HCW over the years 2010 – 2018.MRSA prevalence among samples in contact tracing MethodsA retrospective, observational study was performed in a Dutch teaching hospital. All HCW who had unprotected contact with an MRSA carrier were included in contact tracing. When there had been a long period of unprotected admission prior to an MRSA finding, or when the index case was a HCW, than the entire (nursing) team was tested. All samples of HCWs who were tested for MRSA carriage as part of contact tracing from 2010 until 2018 were included. A pooled nose, throat and perineum swab was collected using the eSwab medium (Copan) and inoculated on chromID MRSA agar plates (bioMérieux) after enrichment in a broth.ResultsIn total, we included 8,849 samples (range: 677 – 1,448 samples per year) from a total of 287 contact tracings (range: 26 – 55 contact tracings per year). Thirty two HCWs were colonized with MRSA (0.36%; 95%CI 0.26 – 0.51). None of them developed a clinical infection.Eight HCWs (0.10%; 95%CI 0.05% – 0.19%) were colonized with the same MLVA type as the index case, and were detected in 6/287 contact tracings (2%). In 4/8 of these cases, a positive HCW was the index for undertaking contact tracing. In 3/8 cases it was clear that the HCW who was identified in the contact tracing was the source of the outbreak and was the cause of invasive MRSA infections in patients.Notably, a different MLVA type as the index case was found in 24 HCWs (0,27%; 95%CI 0,18 – 0,40) of which 7/24 HCW (29,2%) were intermittent carriers.ConclusionThis study revealed a sustained low MRSA prevalence among samples in contact tracing of healthcare workers, over nine years. Furthermore, it shows that when MRSA contact tracing is performed according to the national guideline only 1 out 1000 samples results in a secondary case. This is similar to the population carriage rate of MRSA in The Netherlands. More frequently, an unrelated strain is found. These findings raise question marks regarding the efficacy of the current strategy to perform contact tracing after unprotected exposure.Disclosures All Authors: No reported disclosures

Role of Prophylactic Antibiotic Administration in Growth of Methicillin Resistant Staphylococcus Aureus in Rhinoplasty

Background: Septoplasty and septorhinoplasty are common surgical procedures in modern surgical practice. Pre or postoperative antibiotic administration has raised concerns about the possible increase in the antibiotic-resistant species. The aim of this study was to evaluate the role of postoperative antibiotic prophylaxis in increasing Methicillin-Resistant Staphylococcus Aaureus species (MRSA) in patients, who underwent septoplasty or septorhinoplasty in Loghman Hakim Hospital in Tehran, Iran.Methods: A total of 102 patients, who were planned to undergo septoplasty or septorhinoplasty, participated in this double-blind randomized clinical trial. The patients were divided into the case (n=60, mean age of 28.2 years) and control (n=38, mean age of 28.9 years) groups. Overall, 98 patients participated in the study. The case group received a preoperative injection of cephalothin (1g) and postoperative oral cephalexin regimen (500mg 4 times a day for 7 days). The control group only received a preoperative injection of cephalothin (1g). Vestibular nasal swab cultures were obtained preoperatively and on postoperative day 7. The samples were, then, quickly transferred to the laboratory and cultured on proper media. The results indicated that five MRSA species in the case group and tow MRSA species in the control group were present, postoperatively.Results: The findings of this study suggest that oral antibiotic prophylaxis may lead to a statically non-significant increase in MRSA infection in patients, who require this treatment. Conclusion: Further knowledge of the endogenous nasal flora and the microbiology of common pathogens in patients undergoing septorhinoplasty will help reduce the incidence of infectious complications to a greater level.

Microbiología de las infecciones de úlceras por presión y de origen vascular

IntroductionPressure ulcer (PU) infection is a significant clinical problem in many elderly patients. Material and methodsTo determine the microbiology of PU and vascular ulcer (VU) infections by conducting a cross-sectional study of outpatients treated in a chronic wounds unit over an 18 month period. ResultsSixty six patients with PU infection and 159 patients with an infected VU were identified. The PUs were located below the knee in 36 patients (52%). Patients with pressure ulcers had a higher proportion of institutionalization, cognitive impairment, inability to walk, and sphincter incontinence. There was a greater number of infections caused by Enterobacteriaceae (52%, P=.002) and fewer S. aureus infections (24%, P<.001) in patients with a PU compared to those with those with a VU. Forty-one percent of S. aureus strains isolated in all the patients were resistant to methicillin (MRSA). The proportion of Enterobacteriaceae infections was similar in patients with infection of pelvic girdle PU and in those located below the knee. ConclusionsPU patients suffer a higher rate of infection by enterobacteria. The most common pathogen in UV infections is S. aureus. The proportion of MRSA infection in patients with chronic wounds is high. The microbiology of the infection in the pelvic girdle PU is similar to those located below the knee.

Colonisation with methicillin-resistantStaphylococcus aureusprior to renal transplantation is associated with long-term renal allograft failure

Renal transplant recipients are at an increased risk of developing Methicillin-resistant Staphylococcus aureus due to their immunosuppressed status. Herein, we investigate the incidence of MRSA infection in patients undergoing renal transplantation and determine the effect of MRSA colonisation on renal allograft function and overall mortality. Between January 1st 2007 and December 31st 2012, 1499 consecutive kidney transplants performed in our transplant unit and a retrospective 1:2 matched case-control study was performed on this patient cohort. The 1-, 3- and 5-year overall graft survival rates were 100%, 86% and 78%, respectively, in MRSA positive recipients compared with 100%, 100% and 93%, respectively, in the control group (P<0.05). The 1-, 3- and 5-year overall patient survival rates were 100%, 97% and 79%, respectively, in MRSA positive recipients compared with 100%, 100% and 95%, respectively, in the control group (P=0.1). In a multiple logistic regression analysis, colonisation with MRSA pre-operatively was an independent predictor for renal allograft failure at 5 years (hazard ratio: 4.6, 95% confidence interval: 1-30.7, P=0.048). These findings demonstrate that the incidence of long-term renal allograft failure is significantly greater in this patient cohort compared with a matched control population.

287Value of Methicillin Resistant Staphylococcus aureus Nasal Swab Screening for Predicting Invasive Methicillin Resistant Staphylococcus aureus Respiratory Infection in Pediatric Patients with Artificial Airways

Background: In our 180-bed, free-standing children’s hospital, all patients admitted to intensive care units or from a nursing facility have a GenXpert MRSA nasal screen. This information is routinely used for isolation purposes, but it has increasingly been used to guide antibiotic usage when patients have a suspected infection. Previous studies have demonstrated that patients with positive MRSA screens are at higher risk for MRSA infection. The objective of this study was to evaluate the predictive value of the MRSA screen result for MRSA infection in patients with suspected respiratory infection as tested by bronchoalveolar lavage (BAL) or tracheal aspirate. Methods: All patients admitted from 1/27/09 to 9/17/13 who had both MRSA screening and BAL or tracheal aspirate performed were retrospectively studied. A total of 1336 pairs of screens and cultures were analyzed for correlation of results using descriptive statistics. Results: There were 196 positive MRSA screens (14.7%). Forty-five respiratory cultures were positive for MRSA. Of these 45 positive cultures, 13 had negative MRSA screens, while 32 had positive screens. Statistical analyses demonstrated a positive predictive value for the screen of 16.3% and a negative predictive value of 98.9%. Sensitivity of the screen for a positive respiratory culture was 71%, and specificity was 87.3%. Relative risk of culture-positive MRSA respiratory infection with respect to positive screen result was 14.8. Conclusion: Our study demonstrates that the MRSA nasal screen has a high negative predictive value for MRSA infection in pediatric patients with artificial airways. While patients with a positive screen are at significantly higher risk for culture positive infection, the sensitivity and positive predictive value of a positive screen are relatively low. Since patients with a negative MRSA screen have a lower risk of MRSA respiratory infection, these data could help guide clinicians toward earlier narrowing of empiric antibiotic choices in patients with MRSA screen results and pending respiratory cultures. However, clinical judgment should be used, as 29% of patients in our cohort with a culture positive MRSA respiratory infection had a negative screen. Further study is warranted to clarify the implications of these results. RESULTS • 1336 screen/culture pairs analyzed, 16 eliminated due to discordant results • 188 (14%) MRSA screen positive • 45 (3.4%) MRSA positive cultures • Relative risk for MRSA infection with respect to positive screen 14.8

Prevalence of Methicillin- Resistant Staphylococcus aureus in Health Personnel of a Second Level Hospital in Mexico City and Its Relationship with the Rate of Nosocomial Infection

Background MRSA infection is an important cause of skin and soft tissue, the colonization increases the risk of infection. We estimate the effect of MRSA in health workers of critical areas of a school hospital from second level in Mexico City and its relation of Nosocomial infections. Methods Were performed nasal cultured in Health Workers (HW) patients were taken culture according to clinical and a questionnaire was completes. Identification of MRSA was determined by susceptibility to oxacillin, and SSCmec gene was identified the PFGE was performed to look for clonality. Statistical analysis was performed. Results Included, 269 patients and 108 of HW, 15% and 12% were MRSA in each group. The relative risk of colonization by MRSA in healthcare workers was 2.77 times higher in intensive care and internal medicine than any other service.The odds of infection with MRSA in hospitalized patients undergoing surgery prior is 41,964 times greater than in patients admitted with other diagnosis. The frequency of SSCmecII was (24/31) in HW and patients. The PFGE indicated the presence of a MRSA clone in both patients and health workers in these critical areas. Conclusions The prevalence of carriers of MRSA in staff was similar to that reported in other hospitals of México. There is no direct evidence to validate that colonized health workers increases the risk of nosocomial MRSA infection in patients.

Epidemiology and staphylococcal cassette chromosome mec typing of methicillin-resistant Staphylococcus aureus isolates in Taiwan: A multicenter study

After community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was identified, new community-onset, healthcare-associated MRSA (HA-MRSA-CO) infections have been noticed as MRSA infection in patients with community-onset infection who have underlying conditions resulting in frequent exposure to the healthcare system. However, previous studies have not thoroughly investigated whether HA-MRSA-CO has characteristics resembling those of CA-MRSA or hospital-onset, healthcare-associated MRSA (HA-MRSA-HO) infection. A multicenter, retrospective study was conducted to analyze the clinical and microbiological data of patients with clinical isolates of MRSA from nine hospitals in Taiwan. In total, 203 patients with MRSA isolates, including 27 patients with CA-MRSA (13.3%), 59 with HA-MRSA-CO (29.1%), and 117 with HA-MRSA-HO (57.6%), were studied. Compared to HA-MRSA-HO isolates, the CA-MRSA and HA-MRSA-CO isolates were associated with a higher proportion of skin and soft tissue infections (81.8% and 65.3% vs. 40.5%, p=0.001 and p=0.002) as well as lesser rate of resistance to ciprofloxacin (33.3% and 50.9% vs. 74.4%, p<0.001 and p=0.002), gentamicin (44.4% and 64.4% vs. 84.6%, p<0.001 and p=0.002), and trimethoprim/sulfamethoxazole (33.3% and 42.4% vs. 58.1%, p=0.02 and p=0.048), and a lower 30-day all-cause mortality rate (7.4% and 0% vs. 20.9%, p<0.001). Most of the CA-MRSA isolates were classified as staphylococcal cassette chromosome mec (SCCmec) type VT (11/27, 40.7%), whereas most HA-MRSA-HO isolates were classified as SCCmec type III (66/117, 56.4%). The CA-MRSA, HA-MRSA-CO, and HA-MRSA-HO clinical isolates significantly differed in their clinical presentations and molecular characteristics.

Preoperative Biliary MRSA Infection in Patients Undergoing Hepatobiliary Resection with Cholangiojejunostomy: Incidence, Antibiotic Treatment, and Surgical Outcome

There have been no reports on the impact of preoperative biliary MRSA infection on the outcome of major hepatectomy. The aim of this study was to review the surgical outcome of patients who underwent hepatobiliary resection after biliary drainage and to evaluate the impact of preoperative biliary MRSA infection. Medical records from 350 patients who underwent hepatobiliary resection with cholangiojejunostomy after external biliary drainage were retrospectively reviewed. Of the 350 study patients, 14 (4.0%) had MRSA-positive bile culture, 246 (70.3%) had positive bile culture without MRSA growth, and the remaining 90 (25.7%) had negative bile culture. In all of the patients with MRSA-positive bile culture, vancomycin was prophylactically administered after surgery. Of the 14 patients, 6 (42.9%) had surgical site infections, including wound infection in 5 patients and intra-abdominal abscess in 2 patients. The incidence of surgical site infection in the 14 MRSA-positive patients was higher but not statistically significant compared to the incidence in other patient groups. All 14 patients tolerated difficult hepatobiliary resection. Of the 350 study patients, 28 (8.0%) had postoperative MRSA infections. Multivariate analysis identified preoperative MRSA-positive bile culture as a significant independent risk factor for postoperative MRSA infection. Preoperative biliary MRSA infection is troublesome as it is an independent risk factor of postoperative MRSA infection. Even in such troublesome situations, however, difficult hepatobiliary resection can be performed with acceptable rates of morbidity and mortality using appropriate antibiotic prophylaxis, including vancomycin, based on bile culture.

Controlling MRSA in head and neck cancer patients: What works?

We aimed to determine any beneficial effect from targeted surveillance, cohort nursing, and restricted health care worker access in controlling MRSA infection in patients undergoing surgery for head and neck cancer. Historical cohort study. In phase 1 data were gathered on MRSA-positive cases admitted from February 1, 2006 to February 28, 2007. In phase 2, from July 1, 2007 to January 31, 2008, eligible patients underwent screening swabs, cohort nursing, and restricted access. In the first phase, 24 patients developed MRSA infection out of a total of 84 eligible admissions. There were 31 eligible admissions during phase 2. None of them had known risk factors for MRSA as per Scottish Infection Standards and Strategy Group (SISS) guidelines. All screened patients were noncarriers of MRSA. Three patients out of this group subsequently developed MRSA during their hospital stay. There was a statistically significant drop in MRSA to 9.6 percent (3/31) during this phase compared to 28.5 percent (24/84) in phase 1. Head and neck cancer patients are at high risk of acquiring MRSA infection. Their targeted surveillance is unlikely to influence their MRSA infection rate. However, cohort nursing with restricted health care worker access may help control MRSA infection in them.

The impact of MRSA on vascular surgery.

To investigate the prevalence of MRSA infection in patients treated in a major vascular unit and examine its consequences. A retrospective case-note review was performed. During the period 1993 to 2000, a total of 172 patients (4.4% of total) were positive for MRSA. Of these 97 were colonised and 75 were infected by MRSA. The proportion of wound or graft infections caused by MRSA has increased (4% in 1994 to 63% in 2000). Three patients developed native artery infection (one following aortic stent insertion and 2 following embolectomy). All patients with aortic graft infection died. All patients with infected prosthetic infrainguinal bypass ended up with an amputation. The prevalence of MRSA infection is increasing. Infection of aortic grafts appears to be uniformly fatal and lower limb graft infection is associated with high limb loss.

MRSA Infection in Patients With Cystic Fibrosis

MRSA Infection in Patients With Cystic Fibrosis

佐賀医科大学附属病院におけるメチシリン耐性黄色ブドウ球菌 (MRSA) 感染症について

Hospital infection with MRSA has increased in Saga Medical School Hospital. The causative MRSA consisted predominantly of coagulase type-II strain before 1989, but after 1990, coagulase type-VII MRSA increased rapidly. This type-VII strain has marked multiple drug-resistance, and the pattern of drug sensitivity of MRSA in this hospital was different from that of MRSA detected in other facilities, which are clinically serious problems, therefore, we conducted an etiological study of the background of the increase in MRSA infection in our hospital. The results of the study are summarized as follows: 1) The proportions of MRSA (on strain from one patient) to all types of S. aureus detected in the hospital were 26% for 1986, 23% for 1988, 37% for 1989, 30% for 1990 and 60% for 1991. The proportion increased greatly in 1991. 2) Coagulase type VII-MRSA was first detected only in 5 patients in 1989, then it tended to spread, and this type (probably derived from the same strain) accounted for 47% of MRSA infection in patients examined in 1991. 3) The study of the drug sensitivity pattern and etiological survey of the infection showed that coagulase type VII-MRSA prevalent in the hospital consisted of two types: CLDM, and EM-sensitive, IPM/CS, and MINO-resistant and TSST-1 non-producing and enterotoxin non-producing type, and CLDM, and EM-sensitive, IPM/CS, and MINO-resistant and TSST-1 non-producing type with enterotoxin serotype A. 4) Coagulase type VII-MRSA (Probably derived from the same strain) was detected in physicians and nurses working in affected wards and also in the patients's room.(ABSTRACT TRUNCATED AT 250 WORDS)