Active surveillance to determine the impact of methicillin resistance on mortality in patients with bacteremia and influences of the use of antibiotics on the development of MRSA infection

Introduction Methicillin-resistant Staphylococcus aureus (MRSA) is among the most important pathogens of nosocomial infections, mainly in intensive care units (ICUs), and accounts for 40-60% of all healthcare-associated S. aureus infections. We evaluated the incidence of nosocomial infection by S. aureus, identified the risk factors for MRSA infection, and evaluated the effect of resistance to methicillin on mortality in patients. Methods We conducted MRSA surveillance at a university hospital in Brazil from January 1, 2010, to December 31, 2010, and performed a retrospective case-control matched study to evaluate the frequency of subsequent MRSA bacteremia and death among patients. We evaluated and compared the risk factors between patients with MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infection. Results Sepsis was the most common cause of infection (17.7/1,000 patient-days), followed by surgical site (11.4/1,000 patient-days), pneumonia (4.1/1,000 patient-days), and urinary tract infection (2.4/1,000 patient-days). The significant risk factors were time of hospitalization, use of central vascular catheter (CVC), urinary catheter, nasogastric tube, parenteral nutrition, tracheostomy, mechanical ventilation, and previous antibiotic administration, the latter of which was the only independent risk factor for MRSA infection. Mortality was significantly higher in patients with MRSA. The number of antibiotics tested was not related to increases in the frequency of MRSA/1,000 patient-days. The incidence of mortality attributable to MRSA (bloodstream infection) BSI was 50%. Conclusions Surveillance results showed that the use of high levels of antibiotics was directly related to the development of MRSA infection, and the mortality attributable to MRSA in patients with bacteremia was significant.

Nosocomial infections in a neonatal intensive care unit during 16 years: 1997-2012

Introduction Surveillance of nosocomial infections (NIs) is an essential part of quality patient care; however, there are few reports of National Healthcare Safety Network (NHSN) surveillance in neonatal intensive care units (NICUs) and none in developing countries. The purpose of this study was to report the incidence of NIs, causative organisms, and antimicrobial susceptibility patterns in a large cohort of neonates admitted to the NICU during a 16-year period. Methods The patients were followed 5 times per week from birth to discharge or death, and epidemiological surveillance was conducted according to the NHSN. Results From January 1997 to December 2012, 4,615 neonates, representing 62,412 patient-days, were admitted to the NICU. The device-associated infection rates were as follows: 17.3 primary bloodstream infections per 1,000 central line-days and 3.2 pneumonia infections per 1,000 ventilator-days. A total of 1,182 microorganisms were isolated from sterile body site cultures in 902 neonates. Coagulase-negative staphylococci (CoNS) (34.3%) and Staphylococcus aureus (15.6%) were the most common etiologic agents isolated from cultures. The incidences of oxacillin-resistant CoNS and Staphylococcus aureus were 86.4% and 28.3%, respectively. Conclusions The most important NI remains bloodstream infection with staphylococci as the predominant pathogens, observed at much higher rates than those reported in the literature. Multiresistant microorganisms, especially oxacillin-resistant staphylococci and gram-negative bacilli resistant to cephalosporin were frequently found. Furthermore, by promoting strict hygiene measures and meticulous care of the infected infants, the process itself of evaluating the causative organisms was valuable.

The occurrence and dissemination of methicillin and vancomycin-resistant Staphylococcus in samples from patients and health professionals of a university hospital in Recife, State of Pernambuco, Brazil

Introduction Methicillin-resistant Staphylococcus aureus (MRSA) strains have been responsible for many nosocomial outbreaks. Within hospitals, colonized employees often act as reservoirs for the spread of this organism. This study collected clinical samples of 91 patients admitted to the intensive care unit (ICU), hemodialysis/nephrology service and surgical clinic, and biological samples from the nasal cavities of 120 professionals working in those environments, of a University Hospital in Recife, in the State of Pernambuco, Brazil. The main objective of this study was to determine the occurrence and dissemination of methicillin- and vancomycin-resistant Staphylococcus spp. Methods The isolates obtained were tested for susceptibility to oxacillin and vancomycin and detection of the mecA gene. In addition, the isolates were evaluated for the presence of clones by ribotyping-polymerase chain reaction (PCR). Results MRSA occurrence, as detected by the presence of the mecA gene, was more prevalent among nursing technicians; 48.1% (13/27) and 40.7% (11/27) of the isolates were from health professionals of the surgical clinic. In patients, the most frequent occurrence of mecA-positive isolates was among the samples from catheter tips (33.3%; 3/9), obtained mostly from the hemodialysis/nephrology service. Eight vancomycin-resistant strains were found among the MRSA isolates through vancomycin screening. Based on the amplification patterns, 17 ribotypes were identified, with some distributed between patients and professionals. Conclusions Despite the great diversity of clones, which makes it difficult to trace the source of the infection, knowledge of the molecular and phenotypic profiles of Staphylococcus samples can contribute towards guiding therapeutic approaches in the treatment and control of nosocomial infections.

Ecological competition and the incidence of Acinetobacter baumannii bloodstream infections in a teaching hospital in Southeastern Brazil

IntroductionRecently, pathogen ecology has been recognized as an important epidemiological determinant of healthcare-associated infections (HAIs). Acinetobacter baumannii is one of the most important agents known to cause HAIs. It is widespread in healthcare settings and exhibits seasonal variations in incidence. Little is known about the impact of competition with other hospital pathogens on the incidence of A. baumannii infection.MethodsWe conducted an ecological study, enrolling patients who presented with healthcare-associated bloodstream infections (HA-BSIs) from 2005 to 2010 at a 450-bed teaching hospital in Brazil. HA-BSIs were said to be present when bacteria or fungi were recovered from blood cultures collected at least three days after admission. Monthly incidence rates were calculated for all HA-BSIs (overall or caused by specific pathogens or groups of pathogens). Multivariate Poisson regression models were used to identify the impacts of the incidence of several pathogens on the incidence of A. baumannii.ResultsThe overall incidence rate of HA-BSI caused by A. baumannii was 2.5 per 10,000 patient-days. In the multivariate analysis, the incidence of HA-BSI caused by A. baumanniiwas negatively associated with the incidence rates of HA-BSI due to Staphylococcus aureus (rate ratio [RR]=0.88; 95% confidence interval [CI]=0.80-0.97), Enterobacter spp. (RR=0.84; 95%CI=0.74-0.94) and a pool of less common gram-negative pathogens.ConclusionsOur results suggest that competition between pathogens influences the etiology of HA-BSIs. It would be beneficial to take these findings into account in infection control policies.

Avaliação do potencial anti-inflamatório, antioxidante e antimicrobiano de extratos de segurelha, salsa e coentros

Recentemente tem-se observado um crescente interesse pelo uso de plantas aromáticas, devido às inúmeras propriedades benéficas que lhes têm sido associadas, e a sua aplicação em diversas indústrias, como a indústria alimentar e farmacêutica. Este estudo incidiu sob três ervas aromáticas utilizadas comummente em Portugal: coentros, salsa e segurelha. O objetivo do mesmo foi contribuir para um melhor conhecimento das propriedades bioativas das plantas estudadas, através da determinação do seu teor em compostos fenólicos totais e em flavonoides, e avaliação das suas atividades antioxidante, antimicrobiana e anti-inflamatória. A atividade antioxidante foi determinada através de diferentes tipos de ensaios, nomeadamente avaliação da capacidade redutora, com os ensaios FRAP e CUPRAC, avaliação da capacidade de sequestro do radical DPPH• e avaliação da capacidade de sequestro do radical anião superóxido. A atividade antimicrobiana foi determinada utilizando três estirpes microbianas, Staphylococcus aureus, Escherichia coli e Candida albicans. Por sua vez, a ação anti-inflamatória foi determinada através de ensaios in-vivo apenas para a segurelha, utilizando dois modelos, um para a inflamação aguda (modelo de edema da pata induzido pela carragenina) e outro para a inflamação crónica (modelo da colite ulcerativa). Os resultados demonstraram que todos os extratos de plantas aromáticas possuem atividade antioxidante, sendo que o extrato de segurelha foi aquele que apresentou um maior teor de compostos fenólicos e flavonoides, bem como o que demonstrou possuir uma maior atividade antioxidante relativamente aos restantes extratos estudados, o que sugere o envolvimento destes compostos neste tipo de atividade antioxidante. Entre o extrato de coentros e salsa, o extracto de coentros apresentou um teor em compostos fenólicos e uma actividade antioxidante significativamente superior relativamente ao extracto de salsa. O extrato de segurelha foi o único que apresentou ação antimicrobiana, o que poderá indicar que os compostos fenólicos se encontram também interligados com esta propriedade. A atividade anti-inflamatória foi determinada apenas para o extrato de segurelha, sendo que se observou que este possui efeitos benéficos para a inflamação aguda e crónica, o que poderá estar novamente relacionado com o seu teor em fenóis e flavonoides. O efeito anti-inflamatório observado com o extrato de segurelha no modelo de colite pode ser muito útil do ponto de vista de profilaxia pois o extrato foi administrado aos animais logo a seguir à indução da colite e os resultados demonstram haver uma diminuição significativa da extensão e violência dos sinais da inflamação crónica observados no grupo controlo positivo.

Aerobic bacterial profile and antibiotic resistance in patients with diabetic foot infections

ABSTRACTINTRODUCTION: This study aimed to determine the frequencies of bacterial isolates cultured from diabetic foot infections and assess their resistance and susceptibility to commonly used antibiotics.METHODS: This prospective study included 41 patients with diabetic foot lesions. Bacteria were isolated from foot lesions, and their antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method and/or broth method [minimum inhibitory concentration (MIC)].RESULTS: The most common location of ulceration was the toe (54%), followed by the plantar surface (27%) and dorsal portion (19%). A total of 89 bacterial isolates were obtained from 30 patients. The infections were predominantly due to Gram-positive bacteria and polymicrobial bacteremia. The most commonly isolated Gram-positive bacteria were Staphylococcus aureus, followed by Staphylococcus saprophyticus, Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus pneumoniae. The most commonly isolated Gram-negative bacteria were Proteus spp. and Enterobacterspp., followed by Escherichia coli, Pseudomonasspp., and Citrobacterspp. Nine cases of methicillin-resistant Staphylococcus aureus (MRSA) had cefoxitin resistance, and among these MRSA isolates, 3 were resistant to vancomycin with the MIC technique. The antibiotic imipenem was the most effective against both Gram-positive and Gram-negative bacteria, and gentamicin was effective against Gram-negative bacteria.CONCLUSIONS: The present study confirmed the high prevalence of multidrug-resistant pathogens in diabetic foot ulcers. It is necessary to evaluate the different microorganisms infecting the wound and to know the antibiotic susceptibility patterns of the isolates from the infected wound. This knowledge is crucial for planning treatment with the appropriate antibiotics, reducing resistance patterns, and minimizing healthcare costs.

The nares as a CA-MRSA reservoir in the healthy elderly

Abstract:INTRODUCTION:The frequency of methicillin-resistant Staphylococcus aureus (MRSA) has increased in the community. This study evaluated the prevalence of MRSA and community-acquired (CA)-MRSA in 120 healthy elderly.METHODS:The MRSA were evaluated for the presence of the IS256, mecA, agr, icaA, icaD, fnbB , and pvl genes with PCR. Results: Frequency of S. aureus and MRSA colonization was 17.8% and 19%, respectively. CA-MRSA isolate showed SCC mec IV, fnbB+ , and icaD+ .CONCLUSIONS:CA-MRSA was detected, with genotype determined as SCC mec type IV/IS256/ fnbB+ / icaA / icaD+ / bbp-/agr2 / bap / pvl, characterizing this population as a possible reservoir of this organism in the community.

Novel antibiotic-loaded orthopaedic bone cements: insights on drug release profiles and biocompatibility

Acrylic bone cement (BC) is widely used as an anchor of artificial joints. Bacterial infection due to biofilm formation and inflammation are common and difficult to treat problems associated with commercial available BC formulations. Research on novel BC compositions is urgently needed. The main objective of this thesis was to develop a new biocompatible antibiotic-loaded BC with improved release profile. To achieve that aim several additives were incorporated, as an antibiotic (levofloxacin) to combat bacterial growth, an anti-inflammatory drug (diclofenac) to decrease the inflammatory process and two well-known and broadly used biopolymers, alginate and chitosan in order to increase matrix porosity, and in this way to intensify the amount of released drug. Novel BC formulations were tested in order to find the most suitable one that had potential to proceed to clinical application. Numerous tests were conducted as: a) evaluation of drug release profiles in different biomimetic media, b) mechanical and surface studies, c) microbiological activity testing against Staphylococcus aureus and d) in vitro biocompatibility assays (fibroblasts and osteoblasts). In general, the addition of biopolymers increased drug release, didn’t compromised BC mechanical properties and increased BC hydrophilicity. Microbiological testing revealed that Lev[BC]Chi was the only matrix that reduced significantly biofilm formation. On the contrary, alginate and diclofenac loading into BC seemed to increase biofilm growth. Biocompatibility studies showed some decrease in cell viability, in particularly on osteoblasts, mainly due to the high amounts of released drugs. In conclusion, the present work has shown that the matrix with more potential to proceed in further investigations was Lev[BC]Chi. Other conditions (namely additives and drugs concentrations) should be evaluated with the other tested BC matrices before being discharged.

Urinary tract infection in full-term newborn infants: value of urine culture by bag specimen collection

OBJETIVE: to evaluate the efficacy of urine culture by bag specimen for the detection of neonatal urinary tract infection in full-term newborn infants. Retrospective study (1997) including full-term newborn infants having a positive urine culture (>100,000 CFU/ml) by bag specimen collection. The urinary tract infection diagnosis was confirmed by positive urine culture (suprapubic bladder aspiration method). The select cases were divided into three groups, according to newborn infant age at the bag specimen collection: GI (< 48 h, n = 17), GII (48 h to 7 d, n = 35) and GIII (> 7 d, n = 9). Sixty one full-term newborn infants were studied (5.1 % of total infants). The diagnosis was confirmed on 19/61 (31.1 %) of full-term infants born alive. Distribution among the groups was: GI = 2/17 (11.8 %), GII = 10//35 (28.6 %), and GIII = 7/9 (77.7 %). The most relevant clinical symptoms were: fever (GI - 100 %, GII - 91.4 %) and weight loss (GI - 35.3 %, GII - 45.7 %). Urine culture results for specimens collected by suprapubic aspiration were: E. coli GI (100 %), GII (40 %) and GIII (28.6 %), E. faecalis GI (30%), Staphylococcus coagulase-negative GII (20 %) and GIII (42.8 %), and Staphylococcus aureus GII (10 %). Correlation between positive urine culture collection (bag specimen method) and urinary tract infection diagnosis, using relative risk analysis, produced the following results: GI=0.30 (CI95% 0.08-1.15), GII=0.51 (CI 95% 0.25-1.06) and GIII=3.31 (CI95% 1.8-6.06) The most frequent urinary tract infection clinical signs in the first week were fever and weight loss, while non-specific symptomatology occurred later. E. coli was most frequent infectious agent, although from the 7th day of life, staphylococcus was noted. The urine culture (bag specimen method) was effective in detecting urinary tract infection only after the 7th day of life.

Gold nanoprobes for assessing expression of critical genes in the infection pathway of MRSA

Staphylococcus aureus is an important opportunistic pathogen that can cause a wide variety of diseases from mild to life-threatening conditions. S. aureus can colonize many parts of the human body but the anterior nares are the primary ecological niche. Its clinical importance is due to its ability to resist almost all classes of antibiotics available together with its large number of virulence factores. MRSA (Methicillin-Resistant S. aureus) strains are particularly important in the hospital settings, being the major cause of nosocomial infections worldwide. MRSA resistance to β-lactam antibiotics involves the acquisition of the exogenous mecA gene, part of the SCCmec cassette. Fast and reliable diagnostic techniques are needed to reduce the mortality and morbidity associated with MRSA infections, through the early identification of MRSA strains. The current identification techniques are time-consuming as they usually involves culturing steps, taking up to five days to determine the antibiotic resistance profile. Several amplification-based techniques have been developed to accelerate the diagnosis. The aim of this project was to develop an even faster methodology that bypasses the DNA amplification step. Gold-nanoprobes were developed and used to detect the presence of mecA gene in S. aureus genome, associated with resistance traits, for colorimetric assays based on non-crosslinking method. Our results showed that the mecA and mecA_V2 gold-nanoprobes were sensitive enough to discriminate the presence of mecA gene in PCR products and genomic DNA (gDNA) samples for target concentrations of 10 ng/μL and 20 ng/μL, respectively. As our main objective was to avoid the amplification step, we concluded that the best strategy for the early identification of MRSA infection relies on colorimetric assays based on non-crosslinking method with gDNA samples that can be extracted directly from blood samples.

Prevalence rates of infection in intensive care units of a tertiary teaching hospital

OBJECTIVE: To determine the prevalence rates of infections among intensive care unit patients, the predominant infecting organisms, and their resistance patterns. To identify the related factors for intensive care unit-acquired infection and mortality rates. DESIGN: A 1-day point-prevalence study. SETTING:A total of 19 intensive care units at the Hospital das Clínicas - University of São Paulo, School of Medicine (HC-FMUSP), a teaching and tertiary hospital, were eligible to participate in the study. PATIENTS: All patients over 16 years old occupying an intensive care unit bed over a 24-hour period. The 19 intensive care unit s provided 126 patient case reports. MAIN OUTCOME MEASURES: Rates of infection, antimicrobial use, microbiological isolates resistance patterns, potential related factors for intensive care unit-acquired infection, and death rates. RESULTS: A total of 126 patients were studied. Eighty-seven patients (69%) received antimicrobials on the day of study, 72 (57%) for treatment, and 15 (12%) for prophylaxis. Community-acquired infection occurred in 15 patients (20.8%), non- intensive care unit nosocomial infection in 24 (33.3%), and intensive care unit-acquired infection in 22 patients (30.6%). Eleven patients (15.3%) had no defined type. The most frequently reported infections were respiratory (58.5%). The most frequently isolated bacteria were Enterobacteriaceae (33.8%), Pseudomonas aeruginosa (26.4%), and Staphylococcus aureus (16.9%; [100% resistant to methicillin]). Multivariate regression analysis revealed 3 risk factors for intensive care unit-acquired infection: age > 60 years (p = 0.007), use of a nasogastric tube (p = 0.017), and postoperative status (p = 0.017). At the end of 4 weeks, overall mortality was 28.8%. Patients with infection had a mortality rate of 34.7%. There was no difference between mortality rates for infected and noninfected patients (p=0.088). CONCLUSION: The rate of nosocomial infection is high in intensive care unit patients, especially for respiratory infections. The predominant bacteria were Enterobacteriaceae, Pseudomonas aeruginosa, and Staphylococcus aureus (resistant organisms). Factors such as nasogastric intubation, postoperative status, and age ³60 years were significantly associated with infection. This study documents the clinical impression that prevalence rates of intensive care unit-acquired infections are high and suggests that preventive measures are important for reducing the occurrence of infection in critically ill patients.

Atividade antibacteriana e antifúngica de espécies de Gnetum.

Este trabalho trata da determinação da atividade antibiótica dos extratos de Gnetum paniculatum e G. schwackeanum e dos constituintes químicos isolados deste último como resperatrol, gnetina C e E, os quais foram testados contra várias bactérias e fungos. O extrato de Gnetum schwackeanum e dos constituintes químicos isolados deste último como resveratrol, gnetina C e E, os quais foram testados contra várias bactérias e fungos. O extrato de Gnetum schwackeanum e todas as substâncias dele isoladas foram ativos a Staphylococcus aureus. S. epidermis e Mycobacterium smegmatis. Resveratrol e gnetina C são ativos contra a Candida albicans, mas somente gnetina C possui atividade em relação a Candida parapsilosis e Saccharomyces cervisiae. O derivado sintético de gnetina E não mostrou nenhuma atividade. O extrato de G. paniculatum, é completamente inativo à bactéria e fungos o que sugere que a atividade de G. paniculatum, é completamente inativo à bactéria e fungos o que sugere que a atividade de G. schwackeanum deve-se à presença dos hidroxiestilbenos e seus derivados, uma vez que G. paniculatum não contêm esses tipos de substâncias.

Atividade antibacteriana e antifúngica de espécies de Gnetum

Este trabalho trata da determinação da atividade antibíotica dos extratos de Gnetum paniculatum e G. schwackeanum e dos constituintes químicos isolados deste último como resveratrol, gnetina C e E, os quais foram testados contra vários bactérias e fungos. O extrato de Gnetum schwackeanum e todas as substâncias dele isoladas foram ativos a Staphylococcus aureus, S. epidermis e Mycobacterium smegmatis. Resveratrol e gnetina C são ativos contra Candida albicans, mas somente gnetina C possui atividade em relação a Candida parapsilosis e Saccharomyces cerevisiae. O derivado sintético de gnetina E não mostrou nenhuma atividade. O extrato de G. paniculatum, é completamente inativo à bactéria e fungos o que sugere que a atividade de G. schwackeanum deve-se à presença dos hiroxiestilbenos e seus derivados, uma vez que G. paniculatum não contém esses tipos de substâncias.

CALLIPHORIDAE (DIPTERA) IN MANAUS: IV. BACTERIA ISOLATED FROM BLOWFLIES COLLECTED IN STREET MARKETS

Staphylococcus aureus, Escherichia coli, Proteussp., Providenciasp., Citrobactersp. and Klebsiellasp. were isolated from calliphorid flies collected in eight street markets in the city of Manaus, Amazonas State, Brazil. The presence of £. coliin the samples suggests that faecal contamination is occurring and that these flies are potential vehicles of enteropathogenic bacteria to exposed foods.