Successful prevention of the transmission of vancomycin-resistant enterococci in a Brazilian public teaching hospital

INTRODUCTION: Vancomycin-resistant enterococci (VRE) can colonize or cause infections in high-risk patients and contaminate the environment. Our objective was to describe theepidemiological investigation of an outbreak of VRE, the interventions made, and their impact on its control. METHODS: We conducted a retrospective, descriptive, non-comparative study by reviewing the charts of patients with a VRE-positive culture in the University Hospital of Campinas State University, comprising 380 beds, 40 of which were in intensive care units (ICUs), who were admitted from February 2008-January 2009. Interventions were divided into educational activity, reviewing the workflow processes, engineering measures, and administrative procedures. RESULTS: There were 150 patients, 139 (92.7%) colonized and 11 (7.3%) infected. Seventy-three percent were cared for in non-ICUs (p = 0.028). Infection was more frequent in patients with a central-line (p = 0.043), mechanical ventilation (p = 0.013), urinary catheter (p = 0.049), or surgical drain (p = 0.049). Vancomycin, metronidazole, ciprofloxacin, and third-generation cephalosporin were previously used by 47 (31.3%), 31 (20.7%), 24 (16%), and 24 (16%) patients, respectively. Death was more frequent in infected (73%) than in colonized (17%) patients (p < 0.001). After the interventions, the attack rate fell from 1.49 to 0.33 (p < 0.001). CONCLUSIONS: Classical risk factors for VRE colonization or infection, e.g., being cared for in an ICU and previous use of vancomycin, were not found in this study. The conjunction of an educational program, strict adhesion to contact precautions, and reinforcement of environmental cleaning were able to prevent the dissemination of VRE.

Antimicrobial resistance of Helicobacter pylori strains to five antibiotics, including levofloxacin, in Northwestern Turkey

INTRODUCTION: Antibiotic resistance is the main factor that affects the efficacy of current therapeutic regimens against Helicobacter pylori. This study aimed to determine the rates of resistance to efficacy clarithromycin, amoxicillin, tetracycline, levofloxacin and metronidazole among H. pylori strains isolated from Turkish patients with dyspepsia. METHODS: H. pylori was cultured from corpus and antrum biopsies that were collected from patients with dyspeptic symptoms, and the antimicrobial susceptibility of H. pylori was determined using the E-test (clarithromycin, amoxicillin, tetracycline, metronidazole and levofloxacin) according to the EUCAST breakpoints. Point mutations in the 23S rRNA gene of clarithromycin-resistant strains were investigated using real-time PCR. RESULTS: A total of 98 H. pylori strains were isolated, all of which were susceptible to amoxicillin and tetracycline. Of these strains, 36.7% (36/98) were resistant to clarithromycin, 35.5% (34/98) were resistant to metronidazole, and 29.5% (29/98) were resistant to levofloxacin. Multiple resistance was detected in 19.3% of the isolates. The A2143G and A2144G point mutations in the 23S rRNA-encoding gene were found in all 36 (100%) of the clarithromycin-resistant strains. Additionally, the levofloxacin MIC values increased to 32 mg/L in our H. pylori strains. Finally, among the clarithromycin-resistant strains, 27.2% were resistant to levofloxacin, and 45.4% were resistant to metronidazole. CONCLUSIONS: We conclude that treatment failure after clarithromycin- or levofloxacin-based triple therapy is not surprising and that metronidazole is not a reliable agent for the eradication of H. pylori infection in Turkey.

New Delhi metallo-beta-lactamase-1-producing Acinetobacter spp. infection: report of a survivor

Abstract: New Delhi metallo-beta-lactamase-1 (NDM-1) is a bacterial enzyme that renders the bacteria resistant to a variety of beta-lactam antibiotics. A 20-year-old man was hospitalized several times for surgical treatment and complications caused by a right-sided vestibular schwannoma. Although the patient acquired several multidrug-resistant infections, this study focuses on the NDM-1-producing Acinetobacter spp. infection. As it was resistant to all antimicrobials tested, the medical team developed a 20-day regimen of 750mg/day metronidazole, 2,000,000IU/day polymyxin B, and 100mg/day tigecycline. The treatment was effective, and the patient recovered and was discharged from the hospital.

Biological variability in clinical isolates of Trichomonas vaginalis

Eighteen clinical isolates of Trichomonas vaginalis were obtained from women who attended health centers of the Goverment of Madrid. A total of 1,848 vaginal specimens recovered during the gynaecological examination were seeded in culture tubes containing liquid Diamond medium. Pathogenicity to mice was determined after intraperitoneal inoculation of mice by quantification of mortality and gross damage to abdominal organs. As could be expected, a broad variability was obtained, being some of the isolates more virulent than the reference strain. Regarding to metronidazole susceptibility, none resistant isolate was found but different degrees of susceptibility were determined.

Virulence markers and antimicrobial susceptibility of bacteria of the Bacteroides fragilis group isolated from stool of children with diarrhea in São Paulo, Brazil

Bacteroides fragilis has been isolated from several human and non-human monomicrobial and mixed infections. In this study, some virulence markers and the antimicrobial susceptibility of bacteria of the B. fragilis group isolated from children's stools were evaluated. All the 64 isolates showed the following characteristics: capsulated, beta-hemolytic, hydrophilic, and serum-resistant. Only, 24 (37.5%) strains were resistant at 60ºC, for 30 min, and among them, 12 (18.75%) were resistant at 60ºC, for 60 min. Also, none strain was resistant at 100ºC. Four strains were able to hemagglutinate erythrocytes and D-mannose, D-galactose, D-arabinose, and D-xylose inhibited hemagglutination in 2 B. fragilis strains (p76a, p76b). The hemagglutination in the strain B. uniformis p3-2 was inhibited by D-xylose and D-galactose. The bft gene detection and the enterotoxin production were observed only in 13 EF-enterotoxigenic species. Fragilysin activity was confirmed on HT-29 cells. The antimicrobial determination confirmed that both imipenem and metronidazole were efficient against B. fragilis species; all the strains were resistant to lead and nickel. Plasmids of 2.9, 4.4, 4.8, and 8.9 kb were observed in 6 tested strains. These results show the values of the species identification from clinical infections, as well as of the periodic evaluation of the resistance patterns of the B. fragilis group at Brazilian medical institutions.

Survey of antimicrobial susceptibility patterns of the bacteria of the Bacteroides fragilis group isolated from the intestinal tract of children

The bacteria of the Bacteroides fragilis group are considered important clinical pathogens and they are the most common anaerobes isolated from human endogenous infections. In this study, the susceptibility patterns to antibiotics and metals of 114 species of the B. fragilis group isolated from children with and without diarrhea were determined. Susceptibility was assayed by using an agar dilution method with Wilkins-Chalgren agar. All B. fragilis strains were resistant to lead and nickel, but susceptible to metronidazole and imipenem. beta-lactamase production was detected by using biological and nitrocefin methods, respectively, in 50% and 90.6% of the isolates of children with diarrhea and in 60% and 90% of the isolates of children without diarrhea. Our results show an increase of antibiotics and metals resistance in this microbial group, and a periodic evaluation of the antimicrobial susceptibility is needed. In Brazil, the contamination for antibiotics or metal ions is often observed, and it is suggested an increase the antimicrobial resistance surveillance of this microbial group, mainly those isolated from children's diarrhea.

PRELIMINARILY DEVELOPMENT OF A MOISTURE-ACTIVATED BIORESORBABLE POLYMERIC PLATFORM FOR DRUG DELIVERY

Bioresorbable polymeric films were prepared by solvent casting using a tyrosine-derived polycarbonate and metronidazole (MDZ) as the model drug at 2.5%, 5% and 10% (w/w). Drug loading did not affect the water uptake, drug release, polymer degradation or erosion profiles. All devices released approximately 85% (w/w) of the drug within a 1.5 h period. This may be attributed to the rapid water uptake of the polymer. An increase in the water uptake correlated with a linear rate increase of the polymer degradation (0.968 ≤ R2 ≤ 0.999). Moreover, MDZ presented a remarkable plasticizing effect for the polymer and drug loading exerted a significant impact on the mechanical properties of the obtained films. The results obtained can be used to further the development of novel biocompatible and biodegradable polymeric platforms for the delivery of metronidazole and other drugs in a broad range of pharmaceutical applications.

Eradication of Helicobacter pylori infection in patients with duodenal ulcer and non-ulcer dyspepsia and analysis of one-year reinfection rates

Helicobacter pylori (HP) infection is endemic worldwide. The proposed treatment is expensive and there are few reports regarding reinfection rates in Brazil. The aim of this study was to compare the eradication rates obtained with two therapeutic options and to evaluate reinfection one year after treatment. This was a prospective randomized trial with 55 patients. Thirty-nine patients had active duodenal ulcer (DU) and 16 non-ulcer dyspepsia (NUD), and all tested positive for HP. Diagnosis was based on at least two positive tests: ultrarapid urease test, histology and/or culture. Patients were randomized to two groups: group OMC treated with 40 mg omeprazole (once a day), 500 mg metronidazole and 250 mg clarithromycin (twice daily) for 7 days, or group NA treated with 300 mg nizatidine (once a day) and 1000 mg amoxicillin (twice daily) for 14 days. Those patients in whom HP was eradicated were followed up for one year to evaluate reinfection. Twenty-five patients were randomized for OMC and 30 for NA. HP eradication occurred in 20/25 patients (80%) treated with OMC and 13/30 (43%) treated with NA (P = 0.01). After reallocation because of initial treatment failure, the overall eradication rate was 44/51 patients (86%). After an average follow-up of one year, we evaluated 34 patients (23 with DU and 11 with NUD). Reinfection occurred in 3/34 patients (7.6%). We conclude that OMC is effective for HP eradication, and that NA should not be used. Reinfection occurs in 7.6% of the patients in the first year after eradication.

Duodenal gastric metaplasia and Helicobacter pylori infection in patients with diffuse nodular duodenitis

Whether the regression of gastric metaplasia in the duodenum can be achieved after eradication of Helicobacter pylori is not clear. The aim of the present study was to investigate the relationship between H. pylori infection and gastric metaplasia in patients with endoscopic diffuse nodular duodenitis. Eighty-six patients with endoscopically confirmed nodular duodenitis and 40 control patients with normal duodenal appearance were investigated. The H. pylori-positive patients with duodenitis received anti-H. pylori triple therapy (20 mg omeprazole plus 250 mg clarithromycin and 400 mg metronidazole, all twice daily) for one week. A control endoscopy was performed 6 months after H. pylori treatment. The H. pylori-negative patients with duodenitis received 20 mg omeprazole once daily for 6 months and a control endoscopy was performed 2 weeks after treatment. The prevalence of H. pylori infection was 58.1%, and the prevalence of gastric metaplasia was 57.0%. Seventy-six patients underwent endoscopy again. No influence on the endoscopic appearance of nodular duodenitis was found after eradication of H. pylori or acid suppression therapy. However, gastric metaplasia significantly decreased and complete regression was achieved in 15/28 patients (53.6%) 6 months after eradication of H. pylori, accompanied by significant improvement of other histological alterations. Only mild chronic inflammation, but not gastric metaplasia, was found in the control group, none with H. pylori infection in the duodenal bulb. Therefore, H. pylori infection is related to the extent of gastric metaplasia in the duodenum, but not to the presence of diffuse nodular duodenitis.