Características clínicas y pronóstico de la neumonía adquirida en la comunidad causada por Staphylococcus aureus resistente a la meticilina

Introduction

The aim of this study is to describe the epidemiological and clinical features, treatment and prognosis of community-acquired pneumonia (CAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) in two different geographic regions where community-acquired MRSA (CA-MRSA) infections have different frequencies.

Methods

Observational study of patients admitted to two hospitals (one in Argentina, the other in Spain) between March 2008 and June 2012.

Results

We documented 16 cases of CAP caused by MRSA. MRSA accounted for 15 of 547 (2.7%) cases of CAP in Hospital Rodolfo Rossi and 1 of 1258 (0,08%) cases at the Hospital Universitari de Bellvitge (P ≤ .001). Most patients were young and previously healthy. Multilobar infiltrates, cavitation and skin and soft tissue involvement were frequent. All patients had positive blood cultures. Five patients required admission to the intensive care unit. Early mortality (≤ 48 hours) was 19%, and overall mortality (≤ 30 days) was 25%.

Conclusion

CAP caused by MRSA causes high morbidity and mortality rates. It should be suspected in areas with a high prevalence of CA-MRSA infections, and especially in young and healthy patients who present with multilobar pneumonia with cavitation. Mortality is mainly related to septic shock and respiratory failure and occurs early in most cases.     

Hallazgos radiológicos en pacientes con esquistosomiasis importada

Introduction

Imaging techniques, primarily ultrasound, are useful in the diagnosis and monitoring of patients with schistosomiasis in endemic areas.

Methods

Study of 219 patients treated in sub-Saharan Tropical Medicine Unit with a diagnosis of imported schistosomiasis by imaging techniques investigations including plain abdominal radiography and ultrasound.

Results

A total of 17.8% of patients who had an abdominal X-ray showed findings suggestive of schistosomiasis, in most cases bladder calcifications. In 73 patients (41%) ultrasound showed pathological findings, mainly diffuse or focal wall thickening (26 patients), nodular lesions (n = 14), and pseudopolyps (n = 8). One patient, who had a large bladder mass (9 cm) and bilateral ureterohydronephrosis, was finally diagnosed with squamous cell carcinoma of the bladder. Ultrasound liver abnormalities were found in 10 patients, 4 with signs of portal hypertension, of which 3 had the characteristic periportal fibrosis in schistosomiasis.

Conclusion

Imaging studies, especially abdominal and bladder ultrasound, are useful for diagnosis, the study of disease and monitoring of patients with schistosomiasis in non-endemic countries.     

Erradicación de un brote nosocomial de infecciones por Acinetobacter baumannii multirresistente tras el ajuste de cargas de trabajo y refuerzo de precauciones específicas

Introduction

During 2009, an outbreak of multidrug-resistant Acinetobacter baumannii (MDR A. baumannii) infections was detected in a 27-bed intensive care unit, resulting in 25 cases being infected.

Methods

A matched case-control study was conducted to identify risk factors for infection. The colonization pressure, or the proportion of other patients colonized by MDR A. baumannii, was estimated. TISS-28 and Omega scores of each patient were calculated to evaluate nursing work requirements. Conditional logistic regression analyses were carried out.

Results

Breakdowns in hand washing and glove use were observed. Infected patients (cases) were more likely than paired controls to have had longer exposure to invasive devices and antimicrobial treatment. The independent risk factors identified by the multivariate analysis were, mechanical ventilation [odds ratio (OR) = 1.03; 95% confidence interval (CI), 1.01-1.05; P = .01], and exposure to an infected or colonized patient [OR = 1.7; 95% CI, 1.1-2.6; P = .02). A combined infection control strategy was implemented, including strict compliance with isolation precautions, grouping of patients, reinforcing cleaning and disinfection of surfaces, and a decrease in work load. Subsequently, a sharp reduction in the incidence MDR A. baumannii infections was shown. Therapeutic activity scores were significantly higher for cases than for controls.

Conclusion

The results suggest patient-to-patient transmission of MDR A. baumannii. Reinforcement of specific procedures and work load adjustment were essential to eradicate this outbreak.     

Sensibilidad a azitromicina y otros antibióticos en aislados recientes de Salmonella,Shigella y Yersinia

Introduction

Azithromycin represents an alternative option to treat bacterial diarrhea when the antibiotic therapy is indicated. Little is known regarding the susceptibility to azithromycin in enteropathogens in Spain.

Methods

The MICs of azithromycin were determined by E-test against Salmonella non-typhi (SNT), Shigella and Yersinia isolates collected over the last three years (2010-2012). In addition, the susceptibility to other antibiotics usually used to treat gastrointestinal diseases was determined in these isolates by using a microdilution method.

Results

A total of 139 strains of SNT, Shigella and Yersinia were studied. All of them, except one strain, had a MIC ≤ 16 mg/L of azithromycin. In the adult population, 14.7% and 40.6% of SNT and Shigella isolates, respectively, were resistant to at least 2 of following antibiotics: amoxicillin, trimethoprim-sulfamethoxazole and ciprofloxacin. In the pediatric population, 10% of SNT clinical isolates and 28.6% (2/7) of Shigella isolates were resistant to amoxicillin and trimethoprim-sulfamethoxazole.

Conclusions

In our experience, azithromycin would be a useful antibiotic alternative to treat bacterial diarrhea.     

Estandarización de la técnica Dot-ELISA para la detección de anticuerpos anti-Trypanosoma cruzi y su comparación con ELISA y Western blot

Introduction

Chagas disease is considered endemic of Latin America. Because of migration of people from this region to non-endemic areas, such as the United States, Canada and Europe, it has become a major health problem. There are parasitology and serology tests for its diagnosis, but only the latter are useful during the chronic phase. Most of these tests require expensive equipment, which make them also inaccessible for laboratories in endemic areas. In the present work we standardize Dot-ELISA as a diagnostic test for Trypanosoma cruzi infection, since it is an easy, inexpensive and an accessible test.

Methods

A total of 360 samples were tested: 96 sera from Chagas patients and 153 from healthy people; 40 blood samples spots collected and eluted from filter paper were also tested, as well as 71 serum samples of patients with non-related infections. Sensitivity, specificity and kappa index of Dot-ELISA test were calculated, in order to determine a correlation value of this technique compared to ELISA and Western blot that are already being used for diagnosis.

Results

Dot-ELISA obtained 97% sensitivity and 89% specificity, since it showed cross-reaction mainly with Leishmania spp., and a kappa index of 0,79.

Conclusions

Dot-ELISA results correlate well with other tests that are already being used for diagnosis of Chagas disease. As it is easy and inexpensive, it may be useful as an additional diagnostic test or for field studies.     

Utilización de procalcitonina y proteína C reactiva como marcadores de infección en la neutropenia febril de pacientes sometidos a trasplante de progenitores hematopoyéticos

Introduction and objective

Neutropenia is a frequent sign in patients who are going to have a haematopoietic stem cell transplant (HSCT). Infection is an important complication in these patients, which is favoured by immunosuppression and the degree of neutropenia. This study aims to evaluate the diagnostic usefulness of procalcitonin (PCT) and C-reactive protein (CRP) in onco-haematological patients undergoing chemotherapy and HSCT to determine the origin of the fever.

Patients and methods

PCT and CRP values were measured in 30 episodes of febrile neutropenia: before starting chemotherapy, appearance of neutropenia, onset of fever, days 1, 2, 3 and 6 after the onset of fever, and when the febrile episode ended. The episodes were classified as 5 bacteraemia, 3 microbiologically documented infections, 10 clinical infections, and 12 fevers of unknown origin.

Results

The highest PCT mean values corresponded to the group of patients with bacteraemia. Statistically significant differences (P = .04) were found on the second day after the onset of fever. The cut-off point of 0.5 ng/ml showed a sensitivity of 66% and a specificity of 75%. PCR results showed statistically significant differences on days 1, 2 and 3 after the onset of fever (P = .01, P = .003, and P = .002, respectively). The cut-off point of 7.5 mg/L had a sensitivity of 88% and a specificity of 58%.

Conclusions

The combination of PCT and CRP is an insufficient method to detect bacterial infections and may not replace the proper clinical and microbiological diagnosis.     

Candida: epidemiología y factores de riesgo para especies no albicans

Introduction

Nosocomial fungal infections have increased significantly in the last decade. Candida detection in clinical specimens can mean either colonization or an infection which can be local (muguet) or invasive. Knowledge of the species helps in choosing the best treatment. The aims of this study were to determine the frequency and distribution of Candida species detected in clinical samples, to analyze the clinical characteristics of the involved population and to determine the risk factors for Candida non-albicans species.

Methods

Retrospective, observational. Period: 2006-2010. Inclusion criteria: all isolates of Candida in clinical specimens from patients hospitalized —at least 48 hours in a neurological center. We analyzed epidemiological characteristics, co morbidities, risk factors, factors associated with Candida non-albicans detection, antifungal treatment, development of adverse events and mortality.

Results

Candida spp. was isolated from 321 clinical specimens: 139 (43.3%) were C. albicans and 182 (56.7%) Candida non-albicans. The distribution of the sample was: urine 122 (Candida non-albicans 67.2%), airway 81, oropharynx 45 (C. albicans) and candidemia 40 (Candida non-albicans 75%). The most frequent co-morbidity was solid tumor (35.5%). The main risk factors were antibiotic therapy (85.5%), steroid therapy (61.7%) and in ICU at diagnosis (61.6%). The analysis of risk factors and the isolation of Candida non-albicans shows that chemotherapy, previous surgery, treatment with aminopenicillins, carbapenems and glycopeptides were statistically significant (P < .05). There is a trend in neutropenic patients (P = .055) and in ICU at diagnosis (P = .076). Overall survival was 71%.

Conclusions

Candida species distribution varies with the type of sample analyzed. Non-albicans species make up the majority of the isolates. The identification of the species involved per sample helps to optimize treatment. The high frequency of isolation of Candida in patients on steroids and antibiotics and admitted to ICU, is worth pointing out. Patients with previous surgery, treated with the aforementioned antibiotics or chemotherapy, could receive non-azole antifungals in the initial empirical treatment strategy.     

Infección por Rothia mucilaginosa. ¿Un patógeno respiratorio?

Introduction

To describe the spectrum of infections caused by Rothia mucilaginosa.

Methods

Retrospective study of 20 cases diagnosed with R. mucilaginosa from 2009 to 2012.

Results

Pulmonary infection was the most frequent clinical presentation (n = 14, 70%): bronchiectasis infected (10), followed by pleural empyema (2), pneumonia (1) and acute bronchitis (1). Two episodes were of gastrointestinal origin: cholangitis secondary to biliary drainage and secondary peritonitis. Two episodes included bacteremia in patients with hematological malignancy. One patient had a surgical wound infection with bacteremia, and another had a bacteremic urinary tract infection in a patient with nephrostomy.

Discussion

R. mucilaginosa may be responsible for infections of the lower respiratory tract in predisposed patients.     

Epidemiología y características clínicas de los episodios de bacteriemia por Streptococcus pyogenes en Cartagena (Murcia)

Introduction

A gradual increase in severe cases due to Streptococcus pyogenes or Streptococcus beta-hemolytic group A (SGA), has been detected in the last few decades.

Methods

Retrospective study of bacteremia due to S. pyogenes detected between January 2009 and January 2013 in Cartagena. The annual incidence for severe bacteremia has been estimated.

Results

Thirteen cases of SGA bacteremia were recorded. The incidence increased from 0.37 in 2009 to 2.5 cases/100,000 inhabitants in 2012. The predominant focus was skin and soft tissue infections (53%). Early mortality was 20%.

Conclusion

Severe streptococcal disease is rare, but affects individuals with good functional status, and is associated with a high mortality.     

Resistencia a antibióticos y factores de virulencia en aislados clínicos de Salmonella enterica

Introduction

The increase of Salmonella enterica isolates multi-resistant to different antibiotics, including β-lactams and fluoroquinolones, is a problem of clinical importance. The dissemination of Salmonella Typhimurium resistant to ampicillin (AMP)-chloramphenicol (CHL)-streptomycin (STR)-sulphonamides and (SUL)-tetracycline (TET), that harbour the Salmonella Genomic Island type 1 (SGI1), and the acquisition of transferable genetic material have favoured the multi-resistance in this genus.

Methods

A total of 114 clinical S. enterica isolates were studied (period 2009-2010). The susceptibility to 20 antibiotics was determined by disc diffusion and microdilution. The antimicrobial resistance mechanisms and the integrons were analysed by PCR, and sequencing in the AMP^R isolates. In all the bla_PSE-1-positive isolates, the clonal relationship was determined by PFGE, as well as the presence of SGI1 and 29 virulence genes by PCR.

Results

Eighteen different serotypes were found among the 114 isolates studied, Typhimurium (61%) and Enteritidis (16%) being the most prevalent. High percentages of resistance to SUL (68%), TET (58%), AMP (55%) and STR (46%) were observed. The great majority (92%) of 63 AMP^R isolates were multi-resistant, with the AMP-STR-TET-SUL phenotype (19 isolates) being the most frequent one and associated with the bla_TEM-1b + strA-strB + tet(B) + sul2 genotype. Class 1 integrons (7 different structures) were observed in 48% AMP^R isolates, highlighting the bla_OXA-1 + aadA1 structure (8 isolates), one empty integron and non-classical integrons (5 isolates). The bla_PSE-1 gene was detected inside the classical SGI1 structure in 13 clonally-related isolates that showed the same virulence profile.

Conclusions

The high percentage of multi-resistant S. enterica isolates, especially associated to S. Typhimurium, to the AMP, STR, TET and SUL phenotype, and to the bla_TEM-1b + strA-strB + tet(B) + sul2 genotype, shows an important risk of possible failures in the treatment of serious infections caused by this serotype.     

Trastornos psicológicos y calidad de vida en pacientes con bronquiectasias no relacionadas con fibrosis quística

Introduction

Patients with chronic bronchiectasis (BQ) may suffer from psychological disorders. The objective of this study was to assess the presence of anxiety and depression in patients from a specialised BQ Unit, using validated questionnaires.

Patients and methods

We included patients consecutively diagnosed with BQ (unrelated to cystic fibrosis) by high resolution computed tomography in the study. Patients were clinically stable in the previous three weeks and voluntarily completed the Beck Depression Inventory, State-Trait Anxiety Inventory and St. George's Respiratory Questionnaire, after signing the informed consent. They were classified according to their scores on the psychological screening questionnaires, and their results were compared with the clinical, radiological and functional parameters and Quality of Life.

Results

Seventy patients were included, 48 women and 22 men, with a mean age of 64.19 years. Thirty-four percent (34%) of patients showed symptoms of depression, and around 55% had scores above the 50th percentile in trait and state anxiety. The amount of sputum was associated with trait anxiety. Bacterial colonization was related to anxiety (trait and state), especially Pseudomonas aeruginosa colonization. Female patients showed a higher risk of depression. There was no relationship between the Quality of Life scores and the established classifications of anxiety and depression.

Conclusions

A high percentage of patients with BQ presented anxiety (trait and state) and depression. The daily sputum production and bacterial colonization (especially with P. aeruginosa) were the variables most related to anxiety; depression was more common in women. We believe that the presence of psychological disorders should be evaluated, especially in patients with this profile.     

Manifestations vasculaires des infections à Campylobacter fetus subsp. fetus : à propos de deux cas

Introduction

Campylobacter fetus is a rare Gram-negative bacteria affecting especially elderly and immunocompromised patients, and that is responsible of vascular and cutaneous involvement.

Observations

We report two cases of C. fetus infection in two diabetic male patients, aged 75 and 85 years. The first patient was admitted for chronic fever. First-line examinations were inconclusive. Combined positron emission tomography and computed imaging tomography (PET-CT) diagnosed an infection of a previously operated popliteal aneurysm. The patient underwent surgery, and per-operative samples were positive for C. fetus. The second patient was admitted for a leg cellulitis. Blood cultures were positive for C. fetus. PET-CT found a septic superficial thrombophlebitis. The outcome was favorable for both patients with prolonged antibiotic therapy.

Conclusion

Vascular involvement should be suspected in the presence of C. fetus infections. PET-CT may be useful, as other imaging modalities are not always contributive.     

Significado clínico del aislamiento de Staphylococcus aureus en muestras de orina

Introduction

To evaluate the clinical significance of the isolation of Staphylococcus aureus in urine samples.

Methods

A retrospective study was performed on adult patients identified from a microbiology database in a 200-bed general hospital between the years 2000 and 2009. The demographic data, comorbidities, and risk factors, were reviewed, particularly those associated with the concomitant isolation of S. aureus in blood cultures.

Results

The frequency of S. aureus found in urine samples was 0.63%. A total of 43 patients (mean age 68.7 years [SD ± 16], and 58.1% males) were identified in the database. A Charlson comorbidity index > 3 was observed in 20.9%. Concurrent bacteremia was seen in 48.8%. Two groups of patients were distinguished: with concomitant bacteremia (n = 21) or without (n = 22). Intervention in the urinary tract significantly predicted (P = .00004) bacteriuria without bacteremia (81.8%), compared to bacteremia cases (19%). The attributable mortality was 47.6% in patients with bacteremia compared to non-bacteremia (no deaths), even though the appropriate antibiotic treatment was more frequent among patients with bacteremia (92% and 60%, respectively).

Conclusion

The presence of S. aureus in urine was accompanied by bacteremia in half of the cases, but in patients without previous urinary tract intervention such a possibility increased to 81%. Concomitant bacteremia predicts a worse prognosis even with appropriate treatment.     

Anévrismes infectieux de l’aorte. À propos d’une série de dix patients

Purpose

Infectious aortic aneurysms are rare, being responsible of less than 3% of aortic aneurysms. In this study, we report the clinical characteristics and the outcome of patients presenting with infectious aortic aneurysms in an internal medicine unit.

Methods

Diagnosis of infection-related aortic aneurysm was obtained using: computed tomographic scan; and blood cultures, cultures and molecular biology testing of aortic wall and intra-aneurismal thrombus.

Results

The 10 consecutive patients included in this study consisted in eight men and two women with a mean age of 61.7 years. Patients presented with fever (n = 9), asthenia (n = 2), abdominal (n = 4) or chest pain (n = 1), lumbar pain (n = 3). Computed tomographic scan showed aneurysm involving both thoracic and abdominal aorta (n = 1), abdominal (n = 8) or thoracic aorta (n = 1). Isolated microorganisms were: positive Gram cocci (70%) and negative Gram bacilli (30%). All patients underwent both medical and surgical therapy. Outcome was favorable in nine patients; the remaining patient died from aneurismal aortic rupture.

Conclusion

Clinical manifestations revealing infectious aortic aneurysms are variable, including aneurysm rupture as well as atypical abdominal pain with inflammatory syndrome. These latter presentations are more common in patients, who are hospitalized in internal medicine. Our study underlines that this clinical pattern should not be ignored, in order to avoid both diagnostic and therapeutic delay that could lead to life-threatening complications and poor prognosis.     

Distribución de fenotipos clínicos en pacientes con enfermedad pulmonar obstructiva crónica por humo de biomasa y por tabaco

Introduction

Exposure to biomass smoke is a risk factor for chronic obstructive pulmonary disease (COPD). It is unknown whether COPD caused by biomass smoke has different characteristics to COPD caused by tobacco smoke.

Objective

To determine clinical differences between these two types of the disease.

Methods

Retrospective observational study of 499 patients with a diagnosis of COPD due to biomass or tobacco smoke. The clinical variables of both groups were compared.

Results

There were 122 subjects (24.4%) in the biomass smoke group and 377 (75.5%) in the tobacco smoke group. In the tobacco group, the percentage of males was higher (91.2% vs 41.8%, P < .0001) and the age was lower (70.6 vs 76.2 years, P < .0001). Body mass index and FEV₁% values were higher in the biomass group (29.4 ± 5.7 vs 28.0 ± 5.1, P = .01, and 55.6 ± 15.6 vs 47.1 ± 17.1, P < .0001, respectively). The mixed COPD-asthma phenotype was more common in the biomass group (21.3% vs 5%, P < .0001), although this difference disappeared when corrected for gender. The emphysema phenotype was more common in the tobacco group (45.9% vs 31.9%, P = .009). The prevalence of the chronic bronchitis and exacerbator phenotypes, the comorbidity burden and the rate of hospital admissions were the same in both groups.

Conclusion

Differences were observed between COPD caused by biomass and COPD caused by tobacco smoke, although these may be attributed in part to uneven gender distribution between the groups.     

Prevalencia y características epidemiológicas del esófago de Barrett en la provincia de Barcelona

Introduction

The prevalence of Barrett's esophagus (BE) varies from 0.45% to 2.2% in patients who undergo upper endoscopy and is > 12% when the indication is for reflux symptoms. The prevalence has progressively increased in recent years but is unknown in the population of the province of Barcelona.

Objectives

To determine the prevalence of BE and its epidemiological characteristics in our population.

Patients and methods

We prospectively evaluated patients referred to the Endoscopy Unit of Hospital Clinic and Hospital General de Catalunya for an upper endoscopy. We excluded patients with known BE, prior upper endoscopy, esophagogastric surgery or refusal to participate in the study. Demographic data, alcohol intake, Helicobacter pylori infection and consumption of antisecretory agents were recorded, among other information. Participants completed a standardized questionnaire to assess the presence of gastroesophageal reflux disease (GERD) symptoms and their severity.

Results

Between July 2010 and July 2012, we included 200 patients (100 in each center). The mean age was 48.9 ± 15.6 years and the majority were women (n = 120, 60%). Symptoms of GERD were present in 46 patients (23%) and some degree of esophagitis was present in 31 (15.5%). Infection by H. pylori was present in 29.7%. BE was found endoscopically in 14 (7%) patients, but was histologically confirmed in only 8 (4%). The only variable that correlated with the finding of BE was male sex.

Conclusion

The prevalence of BE in our environment is similar to that reported in Western countries. The absence of reflux symptoms does not rule out the possibility of BE.     

Colonización nasal por Staphylococcus aureus en estudiantes de medicina: importancia en la transmisión hospitalaria

Background

Staphylococcus aureus is the main pathogen causing nosocomial infections. Health professionals, including medical students, could be a source of transmission. The aims of the study were to determine the rate of nasal carriage of S. aureus susceptible and resistant to methicillin (MRSA) and evaluate the knowledge and adherence that students had about hand hygiene.

Methods

The study included medical students attached to the Hospital Universitario 12 de Octubre (Madrid, Spain). We collected samples from both nasal vestibules, and the antimicrobial susceptibility was determined on all isolates. Data collection was performed using a self-administered questionnaire that included risk factors for colonization, hygiene habits and knowledge of hand hygiene protocols.

Results

Of the 140 students included, 55 (39.3%) were colonized by S. aureus, and 3 (2,1%) by MRSA. The exposure to antibiotics in the last 3 months was lower in colonized students (12.3% vs. 25.9%, P = .03). Self-assessment showed that 56.4% of students almost never washed their hands before to attending to the first patient, and only 38.6% always washed after examining patients. More than a third (35.7%) ignored the hand hygiene protocol, and 38.6% had not received specific formation.

Conclusions

Medical students should be included in hospital infection control programs. Hand hygiene training should be given to students before they begin their practices in the hospital.     

LCT-13910C > T polymorphism-associated lactose malabsorption and risk for colorectal cancer in Italy

Background

The activity of epithelial lactase (LCT) associates with a polymorphism 13910 bp upstream the LCT-encoding gene (LCT-13910C > T). The relationship between LCT-13910C > T polymorphism and risk for colorectal cancer is unclear.

Aims

We examined the relationship between the LCT-13910C > T polymorphism causing lactose intolerance and risk for colorectal cancer/polyps onset in the Italian population.

Patients and methods

793 subjects (306 with colorectal cancer, 176 with polyps and 311 controls) were genotyped for the LCT-13910C > T variant by TaqMan real time-PCR.

Results

Lactose malabsorption linked to the CC genotype did not associate with an increased risk for either colorectal cancer (OR = 1.041; 95% CI = 0.751–1.442; p = 0.868) or polyps (OR = 0.927; 95% CI = 0.630–1.363; p = 0.769). There was no association with colorectal cancer/polyps site. 60% of the subjects overall bore the CC genotype.

Conclusion

In the Italian population the LCT-13910C > T polymorphism is not associated to the risk for colorectal cancer or polyps.     

Empiric outpatient therapy with trimethoprim-sulfamethoxazole, cephalexin, or clindamycin for cellulitis

Background

Limited data exist on optimal empiric oral antibiotic treatment for outpatients with cellulitis in areas with a high prevalence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections.

Methods

We conducted a 3-year retrospective cohort study of outpatients with cellulitis empirically treated at a teaching clinic of a tertiary-care medical center in Hawaii. Patients who received more than 1 oral antibiotic, were hospitalized, or had no follow-up information were excluded. Treatment success rates for empiric therapy were compared among commonly prescribed antibiotics in our clinic: cephalexin, trimethoprim-sulfamethoxazole, and clindamycin. Risk factors for treatment failure were evaluated using multivariate logistic regression analysis.

Results

Of 544 patients with cellulitis, 405 met the inclusion criteria. The overall treatment success rate of trimethoprim-sulfamethoxazole was significantly higher than the rate of cephalexin (91% vs 74%; P < .001), whereas clindamycin success rates were higher than those of cephalexin in patients who had subsequently culture-confirmed MRSA infections (P = .01), had moderately severe cellulitis (P = .03), and were obese (P = .04). Methicillin-resistant S. aureus was recovered in 72 of 117 positive culture specimens (62%). Compliance and adverse drug reaction rates were not significantly different among patients who received these 3 antibiotics. Factors associated with treatment failure included therapy with an antibiotic that was not active against community-associated MRSA (adjusted odds ratio 4.22; 95% confidence interval, 2.25-7.92; P < .001) and severity of cellulitis (adjusted odds ratio 3.74; 95% confidence interval, 2.06-6.79; P < .001).

Conclusion

Antibiotics with activity against community-associated MRSA, such as trimethoprim-sulfamethoxazole and clindamycin, are preferred empiric therapy for outpatients with cellulitis in the community-associated MRSA-prevalent setting.