Systemic infection caused by the methicillin-resistant Staphylococcus aureus USA300-LV lineage in a Brazilian child previously colonized

ABSTRACT The methicillin-resistant Staphylococcus aureus (MRSA) USA300-Latin American variant (USA300-LV) lineage is well documented in northern Latin American countries. It has replaced established clones in hospital environments. We herein report a systemic infection caused by a USA300-LV isolate in a 15-year-old boy, from a low-income area of Rio de Janeiro, previously colonized by the same strain. During hospital stay, seven pvl-positive MRSA USA300-LV isolates were recovered by nasal swab, blood and abscess secretion. The patient underwent intravenous vancomycin, daptomycin, and oral sulfamethoxazole/trimethoprim, and was discharged after 45 days after full recovery. This is the first documented case of a community-acquired MRSA infection caused by the USA300-LV variant in Brazil in a previously colonized adolescent with no history of recent travel outside of Rio de Janeiro. The need for improved surveillance programs to detect MRSA colonization in order to control the spread of hypervirulent lineages among community and hospital settings is highlighted.

Correlación de colonización de Staphylococcus aureus en mucosa nasal e infecciones faciales de origen no odontogénico / Corelation between Staphylococcus aureus colonization in nasal mucosa and facial infections from non-odontogenic origin

En la actualidad, las tasas que se conocen de colonización de piel y mucosa por el staphylococcus aureus están incrementando día a día. Se ha encontrado una fuerte correlación de la invasión de estos en otras partes del cuerpo (zona axilar, mucosa nasal, entre otras) con la aparición de celulitis y/o abscesos faciales. Se demostró que la flora nasal es muy diversa, encontrándose patógenos como streptococcus viridans, staphylococcus aureus, staphylococcus coagulasa negativa y Corynebacterium sp, pero sin posibilidad de definir con exactitud cuál es la constancia de los mismos pudiendo presentarse variaciones de esta. A su vez, esto se ve agravado por la falta de adherencia al tratamiento por parte de los pacientes y de otras condiciones como, el mismo contagio o predisposición del medio (sudoración, altas temperaturas, mala higiene, etc.), que facilitan la capacidad de dicho microorganismo de tornarse más resistente, incrementar su población y aumentar así la patogenicidad a través de la codificación de una exotoxina llamada Pantón Valentín (SAMR). Se demostrará entonces, la metodología que se llevó a cabo a través de un análisis descriptivo transversal de los casos tratados en el Hospital Mariano y Luciano de La Vega, con el fin de correlacionar causalidad y efecto (AU)

At present, the rates known for skin and mucosa colonization by Sthapylococcus aureus are increasing day by day. A strong correlation has been found of the invasion of these in other parts of the body (axillary area, nasal mucosa, among others, being the latter the most representative), with the appearance of cellulite and/or facial abscesses. It was shown that the nasal flora is very diverse, finding pathogens such as Streptococcus Viridans, Staphylococcus aureus (S aureus), coagulase negative Staphylococcus and Corynebacterium sp, but that has not been defined exactly the constancy of the same, can be presented variations of this. In turn, this is aggravated by the lack of adherence to treatment by patients and other conditions such as the same contagion or predisposition of the medium (sweating, high temperatures, poor hygiene, etc.), which facilitate the capacity of said Microorganism to become more resistant, increase its population and thus increase the pathogenicity through the codification of a exotoxin called Valentín Panty. To prove the methodology that was carried out through a transversal descriptive analysis of the cases treated at the Mariano Hospital and Luciano de La Vega in order to fulfil the objective of correlating causality and Effect (AU)

High prevalence of methicillin resistance and PVL genes among Staphylococcus aureus isolates from the nares and skin lesions of pediatric patients with atopic dermatitis

Staphylococcus aureus is highly prevalent among patients with atopic dermatitis (AD), and this pathogen may trigger and aggravate AD lesions. The aim of this study was to determine the prevalence of S. aureus in the nares of pediatric subjects and verify the phenotypic and molecular characteristics of the isolates in pediatric patients with AD. Isolates were tested for antimicrobial susceptibility, SCCmec typing, and Panton-Valentine Leukocidin (PVL) genes. Lineages were determined by pulsed-field gel electrophoresis and multilocus sequence typing (MLST). AD severity was assessed with the Scoring Atopic Dermatitis (SCORAD) index. Among 106 patients, 90 (85%) presented S. aureus isolates in their nares, and 8 also presented the pathogen in their skin infections. Two patients had two positive lesions, making a total of 10 S. aureus isolates from skin infections. Methicillin-resistant S. aureus (MRSA) was detected in 24 (26.6%) patients, and PVL genes were identified in 21 (23.3%), including 6 (75%) of the 8 patients with skin lesions but mainly in patients with severe and moderate SCORAD values (P=0.0095). All 24 MRSA isolates were susceptible to trimethoprim/sulfamethoxazole, while 8 isolates had a minimum inhibitory concentration (MIC) to mupirocin >1024 μg/mL. High lineage diversity was found among the isolates including USA1100/ST30, USA400/ST1, USA800/ST5, ST83, ST188, ST718, ST1635, and ST2791. There was a high prevalence of MRSA and PVL genes among the isolates recovered in this study. PVL genes were found mostly among patients with severe and moderate SCORAD values. These findings can help clinicians improve the therapies and strategies for the management of pediatric patients with AD.

The Rate of Nasal Colonization of Methicillin-resistant Staphylococcus aureus at Admission to Intensive Care Units in a Secondary Hospital: The Importance of Nasogastric Tube / 병원감염관리

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization has been known as a predictor of intensive care unit (ICU)-acquired MRSA infections. We performed this study to survey the nasal colonization of MRSA among the patients admitted to an ICU and analyze risk factors associated with the colonization. METHODS: A retrospective 1:1 matched case-control study was conducted with patients admitted to the ICU from March to December 2010 at Samsung Changwon Hospital. RESULTS: A total of 602 patients among 846 patients admitted to the ICU during the study period were evaluated. The prevalence of nasal MRSA colonization was 67 (11.1%) of 602. Other factors, including underlying renal disease (odds ratio [OR]=12.37, 95% confidence interval [CI] 3.60-42.54; P<0.001), MRSA infection within the previous 3 months (OR=7.43, 95% CI 1.31-42.05; P=0.023), nursing home resident within the previous 1 month (OR=6.25, 95% CI 1.82-21.53; P=0.004), surgical procedure within the previous 1 month (OR=5.93, 95% CI 1.86-18.85; P=0.003), and current use of nasogastric tube (OR=4.98, 95% CI 1.84-13.45; P=0.002) were independently associated with nasal MRSA colonization in patients admitted to ICU. CONCLUSION: A significant number of patients admitted to the ICU in a secondary hospital were colonized with MRSA. The present study showed the possible impact of the presence of a nasogastric tube on the nasal colonization by MRSA. More effective infection control procedures must be developed for patients with nasogastric tube use.

Hospital-associated methicillin-resistant Staphylococcus aureus carrying the PVL gene outbreak in a Public Hospital in Rio de Janeiro, Brazil

Hospital associated methicillin-resist Staphylococcus aureus has long been associated to outbreaks in the hospital environment. In this work, we investigated an outbreak of Hospital associated methicillin-resist Staphylococcus aureus carrying the Panton-Valentine leukocidin gene, which occurred in a large community hospital in Rio de Janeiro, Brazil.

Staphylococcus aureus nasal carriage rates among children between one-to-five years in Barangay Pio Del Pilar, Makati City

Objective@#This study aims to determine the staphylococcal nasal carriage rates of children who are between one-to-five years old and residing in Botanical Gardens, Barangay Pio Del Pilar, Makati City. The following shall also be investigated: antibiotic resistance patterns of isolates, factors associated with S. aureus nasal carriage, and other pathologic organisms colonizing the anterior nares in this population. @*Methods@#Nasal swabs were taken from each subject and cultured after informed consent was obtained. Statistical analysis was performed to determine factors with significant association with nasal colonization. @*Results@#Ten (12.9%) out of 77 subjects were positive for S. aureus nasal colonization, one of which was oxacillin-resistant. Only the gross monthly income showed significant association with nasal carriage (p=0.03, OR = 0.59, 95% CI). Four subjects (5.1%) were carriers of S. pneumoniae. @*Conclusions@#The study shows a relatively low rate of Methicillin Sensitive S. aureus (MSSA) and Methicillin Resistant S. aureus (MRSA) nasal carriage. The MRSA isolate was sensitive to all other anti-staphylococcal drugs tested, similar to other studies on Community Acquired-MRSA (CA-MRSA). Local surveillance studies are essential in the control of CA-MRSA and in guiding local antibiotic policies for staphylococcal infections. Further studies on a bigger population are needed to determine rates, resistance patterns and risk factors associated with nasal colonization.

The Prevalence of Bacterial Nasal Colonization in Patients Undergoing Primary Total Knee Arthroplasty

PURPOSE: The objective of the current study was to investigate the prevalence of bacterial nasal colonization in patients who are undergoing primary total knee arthroplasty and to determine whether the prevalence affects the incidence of deep surgical site infections. MATERIALS AND METHODS: Of the 488 consecutive patients (784 knees) who had been screened for bacterial nasal colonization using nasal swab cultures before elective total knee arthroplasties, 434 patients (88.9%) were available for review at one year postoperatively. We assessed the overall rate of deep surgical site infections in the patients with nasal carriage of bacteria (group I) and in those patients without any bacterial nasal colonization (group II), respectively. RESULTS: Of the 434 patients, 69 (15.9%) had nasal carriage of bacteria. There was 1 infection (0.9%) among 113 knees of 69 patients in group I and 10 infections (1.7%) among 591 knees of 365 patients in group II. Those differences were not statistically significant. CONCLUSION: The prevalence of bacterial nasal colonization in patients undergoing primary total knee arthroplasty was 15.9% and the preoperative nasal carriage of bacteria did not affect the rate of deep surgical site infections.

Performance Evaluation of BD GeneOhm MRSA PCR Assay for Detection of Nasal Colonization of Methicillin-Resistant Staphylococcus aureus at Endemic Intensive Care Units / 대한진단검사의학회지

BACKGROUND: The BD GeneOhm MRSA PCR assay (Becton Dickinson, USA) is a qualitative real-time PCR test for rapid detection of nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA). We evaluated the performance of BD GeneOhm MRSA PCR assay versus MRSASelect (Bio-Rad, France) and broth enrichment cultures for detection of MRSA from nasal swabs. METHODS: From August 2008 to January 2009, 295 nasal swabs were taken from patients in intensive care units and transported to the laboratory with BD CultureSwab Liquid Stuart Single Swab (Becton Dickinson, USA). The swabs were inoculated onto MRSASelect first and then suspended into GeneOhm sample buffer: 100 microliter of the suspension was inoculated into 6.5% NaCl-tryptic soy broth (Becton Dickinson, USA), which was subcultured on MRSASelect after overnight incubation (TSBS). Performances of GeneOhm MRSA and MRSASelect were compared to TSBS. RESULTS: With GeneOhm MRSA, 125 swabs (44.6%) were positive for MRSA, 13 (4.4%) were unresolved, and 2 were not determined. With MRSASelect and TSBS 86 (29.4%) and 106 swabs (36.2%), respectively, were positive. The sensitivity, specificity, and positive and negative predictive value of GeneOhm MRSA were 85.8%, 77.5%, and 72.8% and 93.5%, respectively, and corresponding values for MRSASelect were 78.3%, 94.8%, and 96.5% and 88.9%. Of the 33 patients whose 34 specimens were found false positive in GeneOhm MRSA, 23 patients were MRSA-positive either previously or subsequently to this study. All of the 10 patients with false-negative specimens in GeneOhm MRSA PCR assay were previously MRSA or methicilln-resistant coagulase negative staphylococci (MRCNS)-positive and were treated for MRSA, but they became MRSA-positive after 1 to 4 negative surveillance cultures. CONCLUSIONS: GeneOhm MRSA PCR assay showed a relatively high negative predictive value. However, its low specificity and frequent occurrence of unresolved results would be problematic in the endemic areas with a high prevalence of MRSA.

Rate of Nasal Colonization of Methicillin-Resistant Staphylococcus aureus at Admission to a Medical Intensive Care Unit / 병원감염관리

BACKGROUND: The purpose of this study was to survey the nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA) among the patients admitted in a medical intensive care unit (MICU) and analyze risk factors associated with the colonization. METHODS: The study was carried out on patients admitted into the MICU in a 1,250-bed tertiary care university hospital from January through December 2006. Nasal surveillance cultures were obtained from patients within 24 hours of admission to the unit. Data were analyzed retrospectively by the review of medical records. RESULTS: A total of 312 patients were screened with active nasal cultures; 36 patients (11.6%) were positive for MRSA. Of these, 22 (7.1%) were positive in the nasal cultures only and 14 (4.5%) were positive in the cultures of other specimens (13, sputum; 1, joint fluid) in addition to the nasal swabs. Among the risk factors for MRSA nasal colonization were sex (man), route of admission (from other ICUs or wards), a history of ICU admission during the recent 12 months, and prolonged hospital days in ICU. CONCLUSION: MRSA nasal carrier rate was found higher in this study than in those reported in the literature. Most of the patients colonized with MRSA in the nostril were not colonized with the organism elsewhere in the body. Whether or not active surveillance for MRSA should be performed would depend on the nasal colonization rate of the patients at the time of admission to the ICU.

The Methicillin - Resistant Rate of Staphylococcus Aureus Isolated from the Nares and Throat of Patients Admitted to Medical Intensive Care Unit / 결핵및호흡기질환

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in hospital-acquired infection, and is prevalent in intensive care units (ICU). The MRSA colonization rates of the nares and throat were examined in both the ICU and general ward. This study was performed to investigate the MRSA rate and necessity for MRSA screening cultures in patients admitted to ICU. METHODS: Between June and September 2004, those patients admitted to both the medical ICU and general ward participated in this study. Bacterial cultures were performed on swabs of the nares and throat taken within 24 hours of admission. Clinical data were also collected. RESULTS: One hundred and twenty one patients and 84 patients, admitted to the medical ICU and medical general ward, respectively, were investigated. The numbers of nasal MRSA colonization in the ICU and general ward were 3 (2.5%) and 3 (3.6%), respectively. There were 2 (1.7%) cases of throat MRSA colonization in the ICU, but none in the general ward. The MRSA colonization rates of the nares and throat were no different between the ICU and general ward. There were no significant differences in the previous admission, operation history and admission route between the ICU and general ward groups. CONCLUSION: The MRSA colonization rates of the nares and throat were 3.3 and 3.6% in the ICU and the general ward, respectively. The MRSA screening test does not appear to be required in all patients admitted to the ICU, but further studies, including high-risk patients, are recommended.

Prevention of Methicillin-Resistant Staphylococcus aureus Nasal carriage and Infection by Conventional Method and Intranasal Fusidic Acid / 병원감염관리

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens of nosocomial infections. Especially in intensive care units (ICUs) and nasal carriage of Staphylococcus aureus has been known as a major risk factor of staphylococcal infections. In Korea, MRSA is the most common pathogen of nosocomial infections in ICUs. We performed this study to investigate the effects of conventional control measures and the additional effect of intranasal fusidic acid in prevention of MRSA nasal carriage and infection in ICUs of one educational hospital in Korea. METHOD: All patients admitted to medical ICU and surgical ICU in Samsung medical center from April to September 1999 were studied prospectively. Surveillance culture was done in all patients and health care workers by nasal swab culture. We tried to control MRSA infection by conventional methods in the first period April-June 1999) and by additional intranasal fusidic acid application in the second period (July-September 1999) RESULTS: Comparing the first with second periods, new nasal MRSA colonization rate among patients was significantly decreased from 14.8% to 1.8% in surgical ICU (P=0.016). Although there was no statistical difference between the first and second periods in medical ICU (14.6% vs 5.9%, P=0.192), the new nasal colonization of the first period was significantly decreased than that of the previous study which was performed in 1996 (14.6% vs 36.2%, P=0.015). And new MRSA infection rate was much more decreased than the previous study, but there was no statistical significance (11.7% vs 2.0%, P=0.066). CONCLUSION: Conventional methods for MRSA control decreased new MRSA nasal colonization of patients in ICUs. Application of intranasal fusidic acid was considered as an additional control measure for reducing MRSA nasal colonization. For evaluating effect of intranasal fusidic acid for preventing of MRSA infection in ICUs, further study with larger scale of study population is warranted.

A Study on Modes of Transmission and Role of Nasal Carriage to Subsequent Infection with Methicillin-Resistant Staphylococcus aureus in Medical ICU Using PFGE / 병원감염관리

BACKGROUND: In Korea, methicillin-resistant Staphylococcus aureus (MRSA) is the most common nosocomial pathogen, which is particularly prevalent in ICU. We performed this study to investigate the modes of transmission of MRSA and the role of nasal carriage of11RSA to subsequent MRSA infections in medical ICU. METHODS: All patients admitted to the medical lCU during 10 months were studied prospectively. Nasal swabs were done in all patients within 24 hours of admission and weekly thereafter. For patients who developed MRSA infections, additional cultures were done before start of antibiotics. Surveillance cultures of nostril, hands of health care workers and environment were done once at the end of the study. Bacterial typing was performed with pulsed-field gel electrophoresis (PFGE) using Smal. RESULTS: Among 138 patients enrolled, 24 patients (17.4 %) were nasal colonizers, and 9 patients (6.5%) were already infected with MRSA prior to admission. New nasal colonization among patients, in whom follow up nasal cultures were done at the interval of 3 days or more, developed at 36.2 % (21/58 patients). New infections of MRSA in patients who were admitted for more than 3 days, developed at 11.7 % (13/111 patients). Patients in isolation room were infected with MRSA less frequently (P <0.05). No other risk factors for nasal colonization of MRSA or MRSA infections were found. There were no significant differences between nasal colonizers and non-colonizers in the incidence of MRSA infections. PFGE analysis of MRSA isolates from patients showed several major patterns, which were similar in both MRSA isolates obtained prior to admission and those acquired after admission. PFGE patterns of MRSA isolates from health care workers and environment were different from those of patients. CONCLUSION: Patients who were infected or colonized with MRSA seemed to be a major source for transmission of MRSA in medical ICU. In medical lCU, where MRSA were prevalent, nasal colonization was not related to the increased incidence of MRSA infections.