Comparison of teicoplanin disk diffusion and broth microdilution methods against clinical isolates of Staphylococcus aureus and S. epidermidis

The CLSI M100-S19 document has recommended the disuse of vancomycin disks for staphylococci and informed that studies on the action of teicoplanin in disk-diffusion testing should be performed. We describe the comparison of two methods, disk diffusion and broth microdilution, for determining teicoplanin susceptibility in clinical isolates of staphylococci. Overall results showed an aggregation rate of 96.8%; Staphylococcus aureus showed total agreement while S. epidermidis showed 93.8% of agreement. According to these local results, disk diffusion can still be employed to teicoplanin susceptibility determination for staphylococci in our institution.

Identification and antimicrobial susceptibility of Staphylococcus from home-treated peritoneal dialysis patients

Staphylococcus aureus is the main agent of infections during peritoneal dialysis (PD). The presence of S. aureus in the nasal cavity has been extensively studied and suggested as a risk factor of dialysis-related infections, whereas coagulase-negative Staphylococcus (CNS) species are frequently considered part of the normal human microbiota. The aim of this study was to identify Staphylococcus in the nasal cavity, pericatheter skin and peritoneal effluent from PD patients, as well as to evaluate the antimicrobial activity evolution in vitro. Thirty-two chronic PD patients were observed during 12 months and had nasal and pericatheter skin samples collected for culture. When peritonitis was detected, samples were also collected from the peritoneal effluent for culture. The activity of several antimicrobial drugs (penicillin G, oxacillin, cephalothin, ofloxacin, netilmicin and vancomycin) against different Staphylococcus species was measured by using the agar drug diffusion assay (Kirby-Bauer method). Staphylococcus was separated into S. aureus, S. epidermidis and other CNS species in order to determine the in vitro resistance level. S. epidermidis resistance to oxacillin progressively increased during the study period (p < 0.05). Resistance to ofloxacin was inexpressive, whereas resistance to netilmicin and vancomycin was not detected. of the oxacillin-resistant species (n = 74), 83% were S. epidermidis, 13% other CNS and 4% S. aureus (p < 0.05). Regarding multidrug resistant strains (n = 45), 82% were S. epidermidis, 13% other CNS, and 5% S. aureus (p < 0.05). This study shows the relevance of resistance to oxacillin and CNS multi-drug resistance, particularly concerning S. epidermidis, in PD patients.

Estudo sobre a resistencia aos antimicrobianos em bacterias isoladas de pacientes hospitalizados (Botucatu, 1988-1992)

Since 1988 to 1992, a study about susceptibility to antimicrobial drugs of bacterias isolated from hospitalized patients was performed. The compared susceptibility to important drugs (ampicillin, cephalotin, cefoxitin, ceftaxizime, ceftriaxone, aztreonam, gentamicin, amikacin, pefloxacin, ciprofloxacin, imipenem, oxacillin and vancomycin) was investigated in 1200 strains (300 of each specie) of the prevalent bacterias: E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and S. aureus. Minimal inhibitory concentration (MIC) was determined by agar dilution method, using from 0.05 to 256 mcg of each drug per ml of culture medium (Mueller-Hinton). Ranges of MIC, MIC(50%), MIC(90%) and the proportion of resistant strains were determined and permitted to know the 4 drugs that were found to be more active against bacterias; the CIM(90%) values are: E. coli - aztreonam (0.1 mcg/ml), pefloxacin (0.1), ceftazidime (0.25) and ceftriaxone (0.05); K. pneumoniae-aztreonam (0.25) ceftriaxone (0.25), ceftazidime (0.5) and pefloxacin (2.0); P. aeruginosa-imipenem (4.0), aztreonam (16), ceftazidime (16) and ciprofloxacin (16); S. aureus-vancomycin (1.01, ciprofloxacin (8, 0), amikacin (128) and cephalothin (128 mg/ml). The better 'in vitro' antibacterial activity observed was related to: aztreonam (77-100% of the sensitive strains), ceftazidime (50-99,7%), pefloxacin (73-99,7%), ciprofloxacin (80%), imipenem (93%) and vancomycin (100%).

Ocorrência e determinação do perfil de sensibilidade às drogas das cepas de Staphylococcus aureus isoladas de fossas nasais e orofaringe dos servidores hospitalares

Staphylococcus aureus is a very important hospital and community pathogen. This species is related to supurative disease, systemic and widespread metastatic lesions. The ability of S. aureus to develop resistance to antibiotics, more recently to methicillin, associates this bacteria with epidemic outbreaks of severe nosocomial infection. The source of staphylococcal infection is a patient with a staphylococcal lesion or a career member of the hospital staff. We aimed to detect the frequency of S. aureus isolated from anterior nares and oral cavities among the hospital staff in Bauru - SP, and to determine the antibiotic susceptibility of the isolates. Within 213 of the staff members analyzed. S. aureus was found in 94 (44.13%) of careers, with 47 (50%) of nasal carriers, 23 (24.4%) of oral carriers and 24 (25.5%) of both carriers. The biochemical characteristics analyzed for the species identification were similar to S. aureus ATCC 29213. All strains identified as S. aureus showed varied sensibility to the antimicrobial agents tested. No vancomicin resistant strains and only 8 (8.5%) strains with oxacilin resistance were found.

Propolis: anti-Staphylococcus aureus activity and synergism with antimicrobial drugs

Propolis is a natural resinous substance collected by bees from tree exudates and secretions. Its antimicrobial activity has been investigated and inhibitory action on Staphylococcus aureus growth was evaluated The in vitro synergism between ethanolic extract of propolis (EEP) and antimicrobial drugs by two susceptibility tests (Kirby and Bauer and E-Test) on 25 S. aureus strains was evaluated Petri dishes with sub-inhibitory concentrations of EEP were incubated with 13 drugs using Kirby and Bauer method and synergism between EEP and five drugs [choramphenicol (CLO), gentamicin (GEN), netilmicin (NET), tetracycline (TET), and vancomycin (VAN)] was observed. Nine drugs were assayed by the E-test method and five of them exhibited a synergism [CLO, GEN, NET, TET, and clindamycin (CLI)]. The results demonstrated the synergism between EEP and antimicrobial drugs, especially those agents that interfere on bacterial protein synthesis.

Evaluation of the antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus isolated from human infections

Multiresistant Staphylococcus aureus constitutes an important public health problem, especially in view of its possible spread in nosocomial environments. In the present work, we analyzed the susceptibility profile of 80 S. aureus stains from human infections resistant to at least 10 drugs. For this study, the techniques used were the disk method and minimum inhibitory concentration (MIC) of the following drugs: cefuroxime, ciprofloxacin, clindamycin, erythromycin, gentamycin, imipenem, oxacillin, rifampicin, tetracycline and vancomycin, according the criteria of the National Committee for Clinical Laboratory Standards (NCCLS). Methicillin was included in the antibiogram as a marker, which is usually used in drugs selection for the treatment of staphylococcal infections. Results indicated that the most effective drug was vancomycin. For the other 10 drugs, the percentage of resistant strains ranged from 85% to 93.75%. In relation to the MICs, it was observed that vancomycin (MIC 90% = 0.615ug/ml) was the most effective drug; followed by rifampicin (MIC 90% = 2.6ug/ml) and ciprofloxacin (MIC 90% = 26.6ug/ml). The drugs that showed the least effective activity were cefuroxime, clindamycin, erythromycin, gentamycin, and oxacillin. On the other hand, observation of β-lactamase production revealed that most of the methicillin-resistant strains produced β-lactamase (83.7%), potentiating the risks of nosocomial infections. In general, vancomycin still continues to be one of the most effective drugs for staphylococcal infections therapy.

Research on staphylococcus spp in biofilm formations in water pipes and sinsibility to antibiotics

Water from dental equipment presents risks for surgeon-dentists as well as for patients because it might work as a means of dissemination/ transmission of microoganisms. The objective of this study was to verify the quality of the water used in dental equipment by means of microbiological analysis, accomplishing the count of Staphylococcus spp.There have been collected, 160 samples of water from reserviors, taps used for hand washing, air-water syringes, and high-speed handpieces, in 40 dental offices in the city of Barretos, São Paulo. The rules concerning bacteriotogicaI analysis in cfu/mL from Standard Methods for the Examination of Water and Wastewater have been followed. The analysis of the results has made it possible to verify that out of the total of samples, 28% did not meet the standards of potability established by the American Dental Association: Regarding the origin of analyzed S. aureus., the most contaminated sites were high-speed handpicces in private offices (761%) and in, ental care plan offices (71%), followed by air-water syringe in dental care plan offices (64%). For S. epidermitis samples, the most contaminated sites were high-speed handpieces in SUS (Brazilian Government Health System) dental offices (22%) and in dental care plan offices (14%) The most contaminated sites were dental offices that saw Patients under dental care plans, Concerning tested antibiotics, the ones that presented better results as to sensibility to strain S. epidermidis were vancomycin and ciprofloxacin (100%) and, as to sensibility to strain S. aureus, it was ciprofloxacin (97%).

Detecção da produção de slime por estafilococos coagulase-negativa isolados de cateter venoso central

Slime production is an important virulence factor of coagulase-negative Staphylococcus spp., allowing them to attach to smooth surfaces of biomaterials, and it has been associated with infections of implanted medical devices. In the present study the production of slime capsules in 27 strains of coagulase-negative Staphylococcus was investigated by culture in Congo Red agar (77.7% positivity), spectrophotometric or microplate method (81.4% positivity) and scanning electron microscopy (88.9% positivity). The resistance of coagulase-negative strains of Staphylococcus to various antimicrobial agents was also determined by agar disk diffusion. The proportion of strains resistant to penicillin G, oxacillin, erythromycin, clindamycin and gentamicin among the slime-producing staphylococci was 88.9%, 70.4%, 81.5%, 66.7% and 59.2%, respectively; all of the coagulase-negative staphylococci were susceptible to vancomycin. The strains isolated from central venous catheters were identified by a conventional method and the API Staph system. The 27 coagulase-negative Staphylococcus strains were identified as: S. saprophyticus (3.7%), S. xylosus (7.4%), S. haemolyticus (14.8%), S. epidermidis (37.0%), S. warneri (14.8%), S. lugdunensis (7.4%), S. hominis (7.4%), S. schleiferi (3.7%) and S. chromogenes (3.7%). It can be concluded that in the most of the coagulase-negative Staphylococcus species there was an association between slime production, the nosocomial origin of the strains and reduced sensitivity to the antibiotics, suggesting a pathogenic potential in the hospital environment.

Efeito da lavagem peritoneal com bupivacaína na sobrevida de ratos com peritonite fecal

BACKGROUND AND OBJECTIVES: Based on the knowledge of the anti-inflammatory and anti-bacterial actions of local anesthetics (LA), the objective of this study was to determine the effects of peritoneal lavage with bupivacaine on survival of mice with fecal peritonitis. METHODS: Forty-eight Wistar mice, weighing between 300 and 330 g (311.45 ± 9.67 g), undergoing laparotomy 6 hours after induction of peritonitis were randomly divided in 4 groups: 1 - Control, without treatment (n = 12); 2 - Drying of the abdominal cavity (n = 12); 3 - Lavage with 3 mL NS and posterior drying of the abdominal cavity (n = 12); and 4 - Lavage with 8 mg.kg -1 (± 0.5 mL) of 0.5% bupivacaine added to 2.5 mL of NS followed by drying out of the abdominal cavity (n = 12). Animals that died underwent necropsy and the time of death was recorded. Surviving animals were killed on the 11 th postoperative day and underwent necropsy. RESULTS: Group 1 presented a 100% mortality rate in 52 hours, 100% mortality rate in Group 2 in 126 hours, and Group 3 presented a 50% mortality rate in 50 hours. Animals in Group 4 survived. Survival on the 11 th day was greater in groups 3 and 4 than in Groups 1 and 2 (p < 0.001) and greater in Group 4 than in Group 3 (p < 0.01). CONCLUSIONS: Peritoneal lavage with a solution of bupivacaine diluted in NS was effective in preventing death for 11 days in 100% of animals with fecal peritonitis. © Sociedade Brasileira de Anestesiologia, 2008.

Pneumonias

Pneumonia is an infectious disease with great morbidity and mortality worldwide. According to the current guidelines recommendations the authors reviewed the treatment of community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP). In this paper will be presented data about etiology, clinics and diagnostic tools. © Copyright Moreira Jr. Editora.

Necrotizing soft tissue infection of the breast: Case report and literature review

Background: Necrotizing soft tissue infection (NSTI) is characterized by progressive infectious gangrene of the skin and subcutaneous tissue. Its treatment involves intensive care, broad-spectrum antibiotic therapy, and full debridement. Methods: We present two cases of NSTI of the breast, adding these cases to the 14 described in the literature, reviewing the characteristics and evolution of all cases. Case Report: On the fourth day after mastectomy, a 59-year-old woman with ulcerated breast cancer developed Type I NSTI caused by Pseudomonas aeruginosa, which had a favorable evolution after debridement and broad-spectrum antibiotics. The second patient was a 57-year-old woman submitted to a mastectomy and axillary dissection, who had recurrent seromas. On the 32nd post-operative day, after a seroma puncture, she developed Type II NSTI caused by β-hemolytic streptococci. She developed sepsis and died on the tenth day after debridement, intensive care, and broad-spectrum antibiotics. The cases are the first description of breast NSTI after mammary seroma aspiration and the first report of this condition caused by P. aeruginosa. Conclusion: Necrotizing soft tissue infection is rare in breast tissue. It frequently is of Type II, occurring mainly after procedures in patients with breast cancer. The surgeon's participation in controlling the focus of the infection is of fundamental importance, and just as important are broad-spectrum antibiotic therapy and support measures, such as maintenance of volume, correction of electrolytic disorders, and treatment of sepsis and septic shock. Once the infection has been brought under control, skin grafting or soft tissue flaps can be considered. The mortality rate in breast NSTI is 18.7%, all deaths being in patients with the fulminant Type II form. Surgical oncologists need to be alert to the possibility of this rare condition. © 2012, Mary Ann Liebert, Inc.

Photodynamic and Antibiotic Therapy Impair the Pathogenesis of Enterococcus faecium in a Whole Animal Insect Model

Enterococcus faecium has emerged as one of the most important pathogens in healthcare-associated infections worldwide due to its intrinsic and acquired resistance to many antibiotics, including vancomycin. Antimicrobial photodynamic therapy (aPDT) is an alternative therapeutic platform that is currently under investigation for the control and treatment of infections. PDT is based on the use of photoactive dye molecules, widely known as photosensitizer (PS). PS, upon irradiation with visible light, produces reactive oxygen species that can destroy lipids and proteins causing cell death. We employed Galleria mellonella (the greater wax moth) caterpillar fatally infected with E. faecium to develop an invertebrate host model system that can be used to study the antimicrobial PDT (alone or combined with antibiotics). In the establishment of infection by E. faecium in G. mellonella, we found that the G. mellonella death rate was dependent on the number of bacterial cells injected into the insect hemocoel and all E. faecium strains tested were capable of infecting and killing G. mellonella. Antibiotic treatment with ampicillin, gentamicin or the combination of ampicillin and gentamicin prolonged caterpillar survival infected by E. faecium (P = 0.0003, P = 0.0001 and P = 0.0001, respectively). In the study of antimicrobial PDT, we verified that methylene blue (MB) injected into the insect followed by whole body illumination prolonged the caterpillar survival (P = 0.0192). Interestingly, combination therapy of larvae infected with vancomycin-resistant E. faecium, with antimicrobial PDT followed by vancomycin, significantly prolonged the survival of the caterpillars when compared to either antimicrobial PDT (P = 0.0095) or vancomycin treatment alone (P = 0.0025), suggesting that the aPDT made the vancomycin resistant E. faecium strain more susceptible to vancomycin action. In summary, G. mellonella provides an invertebrate model host to study the antimicrobial PDT and to explore combinatorial aPDT-based treatments.

Systemic CA-MRSA infection following trauma during soccer match in inner Brazil: Clinical and molecular characterization

Even though community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) was described a decade ago, reports from Brazil are scarce and cases occurred in large urban centers. We report MRSA sepsis in a 16-year-old male from a small town and who had no history of exposure to healthcare or recent travel. After trauma during a soccer match, he presented swelling in the right thigh, which evolved in a month to cellulitis complicated by local abscess, orchitis and pneumonia. The patient presented severe sepsis, with fever and respiratory failure. Laboratory findings included blood leukocyte counts above 40,000/mm3 and thrombocytopenia. He was submitted to mechanical ventilation and therapy with vancomycin and imipenem. He had a slow but favorable response to therapy and was discharged after six weeks of hospitalization. MRSA grew from blood cultures and respiratory aspirates obtained before antimicrobial therapy. The isolate belonged to sequence type 5, spa type t311, harbored SCCmec type IV and genes for Panton-Valentine leukocidin and Enterotoxin A. The pulsed-field gel electrophoresis pattern was distinct from North American classic CA-MRSA clones. However, the sequence type and the spa type revealed that the clone belong to the same clonal complex isolated in Argentina. This is the first CA-MRSA infection reported in that region, with significant epidemiologic and clinical implications. © 2013 Elsevier Inc.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in a burn unit from Brazil

Methicillin-resistant Staphylococcus aureus (MRSA) poses a threat for patients in burn units. Studies that mix epidemiological designs with molecular typing may contribute to the development of strategies for MRSA control. We conducted a study including: molecular characterization of Staphylococcal Chromosome Cassette mecA (SCCmec), strain typing with pulsed field gel electrophoresis (PFGE) and detection of virulence genes, altogether with a case-case-control study that assessed risk factors for MRSA and for methicillin-susceptible S. aureus (MSSA), using S. aureus negative patients as controls. Strains were collected from clinical and surveillance cultures from October 2006 through March 2009. MRSA was isolated from 96 patients. Most isolates (94.8%) harbored SCCmec type III. SCCmec type IV was identified in isolates from four patients. In only one case it could be epidemiologically characterized as community-associated. PFGE typing identified 36 coexisting MRSA clones. When compared to MSSA (38 isolates), MRSA isolates were more likely to harbor two virulence genes: tst and lukPV. Previous stay in other hospital and admission to Intensive Care Unit were independent risk factors for both MRSA and MSSA, while the number of burn wound excisions was significantly related with the former (OR = 6.80, 95%CI = 3.54-13.07). In conclusion, our study found polyclonal endemicity of MRSA in a burn unit, possibly related to importing of strains from other hospitals. Also, it pointed out to a role of surgical procedures in the dissemination of MRSA strains. © 2013 Elsevier Ltd and ISBI. All rights reserved.