Evaluation of physicochemical and microbiological stability of liquid preparation from tizanidine hydrochloride tablets - a Hospital concern

Tizanidine hydrochloride is a centrally acting skeletal muscle relaxant, used in the management of spasticity. This drug is commercially available only as tablets, which highlights the need to develop oral liquid formulations. In the hospital environment, this aspect is circumvented by the preparation of suspensions, to allow administration to children and adults with impaired swallowing, but there are no data regarding their stability. The purpose of this study was to evaluate the physicochemical andmicrobiological stability of liquid dosage forms prepared in the hospital environment from tizanidine hydrochloride tablets, applying high performance liquid chromatography (HPLC) and microbiological analysis. A simple and stability-indicating HPLC method was developed and validated for specificity, linearity, limits of detection and quantification, precision, accuracy and robustness. The liquid formulations were placed in amber PET and glass bottles, which were stored under three different conditions: at room temperature, under refrigeration and at 40 ºC. The liquid formulations were analyzed and demonstrated chemical stability for 56 days, allowing their use for long periods. However, the determination of microbiological stability showed that these formulations are prone to microbial contamination, which has dramatically reduced its stability to 7 days, in both bottles and at all evaluated temperatures

Nutritional requirement among Pseudomonas aeruginosa isolates recovered from respiratory clinical specimens at a tertiary hospital from South of Brazil

We screened 349 isolates of P. aeruginosa from cystic fibrosis (CF+) and non-cystic fibrosis (CF-) patients for the auxotrophy. Fourteen (4.0 percent) were auxotrophic and among them only one was recovered from CF-patient showing that this characteristic is strongly associated with cystic fibrosis. In total, a requirement for 5 different compounds (or combination) was verified and, of these, methionine was the most common single amino acid required. Only one auxotrophic isolate was no able to produce biofilm in vitro.

High vancomycin resistance among biofilms produced by Staphylococcus species isolated from central venous catheters

Biofilm production is an important mechanism that allows microbes to escape host defences and antimicrobial therapy. Vancomycin has been used largely for the treatment of methicillin-resistant staphylococcal infections. Here, we determined the minimal inhibitory concentration (MIC) and minimal biofilm eradication concentration (MBEC) for 82 Staphylococcus species isolated from central venous catheters (CVC). Our results showed that the 41 strong and moderate-biofilm-producing isolates presented a higher MBEC/MIC ratio for vancomycin than the 24 weak-biofilm-producing isolates, illustrating the importance of biofilm production ability and the difficulty in treating biofilm-related infections. The MBEC was significantly higher in moderate-biofilm-producing isolates than in weak-biofilm-producing isolates (p < 0.001) and in strong-biofilm-producing isolates than in weak-biofilm-producing isolates (p = 0.001). The correlation between the MIC and the MBEC was poor. Based on our results, we recommend that bacterial biofilms be suspected in all cases of CVC infection.

High prevalence of methicillin-resistant Staphylococcus aureus with SCCmec type III in cystic fibrosis patients in southern, Brazil / Alta prevalência de Staphylococcus aureus resistente à meticilina com SCCmec tipo III em pacientes com fibrose cística no sul do Brasil

INTRODUCTION: Bacterial colonization of the lungs is the main cause of morbidity in cystic fibrosis (CF). Pathogens such as Staphylococcus aureus are very well adapted to the pulmonary environment and may persist for years in the same patient. Genetic determinants of these bacteria, such as the presence of SCCmec have recently emerged as a problem in this population of patients. METHODS: Staphylococcus aureus isolates obtained from different clinical materials coming from CF and non-CF patients attended at a cystic fibrosis reference hospital were compared according to SCCmec type and antibiotic susceptibility profile. RESULTS: Three hundred and sixty-four single-patient Staphylococcus aureus isolates were collected, of which 164 (45 percent) were from CF patients. Among the latter, 57/164 (44.5 percent) were MRSA, and among the non-CF patients, 89/200 (35 percent) were MRSA. Associated pathogens were found in 38 CF patients. All 57 MRSA from CF patients harbored the multiresistant cassette type III. In contrast, 31/89 MRSA from non-CF patients harbored SCCmec type I (35 percent) and 44/89 harbored type III (49 percent). The antibiotic susceptibility pattern was similar between CF and non-CF patients. CONCLUSIONS: The high prevalence of multiresistant SCCmec type III among CF patients compared with non-CF patients in our institution may make it difficult to control disease progression through antibiotic therapy for promoting the survival of this kind of patient.

INTRODUÇÃO: Colonização pulmonar bacteriana é a principal causa de morbidade em fibrose cística (FC). Patógenos como Staphylococcus aureus são muito bem adaptados ao ambiente pulmonar e podem persistir por anos no mesmo paciente. Determinantes genéticos desta bactéria, como presença de SCCmec emergiram recentemente como um problema nesta população de pacientes. MÉTODOS: Foram comparados isolados de Staphylococcus aureus obtidos de diferentes materiais clínicos, de pacientes com e sem FC atendidos em um hospital de referência em tratamento de fibrocísticos de acordo com o tipo de SCCmec e o perfil de susceptibilidade aos antimicrobianos. RESULTADOS: Foram coletados 364 Staphylococcus aureus, um isolado por paciente, sendo 164 (45 por cento) de pacientes com FC. Entre estes pacientes, 57/164 (44,5 por cento) eram MRSA, e entre pacientes não fibrocísticos, MRSA compreendiam 89/200 (35 por cento). Foram encontrados outros patógenos, associados ao Staphylococcus aureus, em 38 pacientes com FC. Todos 57 MRSA de pacientes com FC possuíam o cassete de multiresistência tipo III. Por outro lado, 31/89 MRSA de pacientes não fibrocísticos possuíam SCCmec tipo I (35 por cento) e 44/89 possuíam tipo III (49 por cento). O perfil de susceptibilidade aos antimicrobianos foi similar entre pacientes com e sem FC. CONCLUSÕES: A alta prevalência do SCCmec de multiresistência tipo III entre pacientes com FC comparado com pacientes sem FC em nossa instituição pode dificultar o controle da progressão da doença, feito através da antibioticoterapia, e que promove a sobrevivência deste tipo de paciente.

Avaliação do perfil de suscetibilidade antimicrobiana de Enterococcus spp. isolados em dois hospitais de Porto Alegre - RS, Brasil / Evaluation of antimicrobial susceptibility profile of Enterococcus spp isolated in two hospitals of Porto Alegre - RS, Brazil

O perfil de suscetibilidade antimicrobiana de 203 isolados de Enterococcus spp provenientes de diferentes amostras clínicas em dois hospitais de Porto Alegre, Rio Grande do Sul, Brasil, foram estudadas. As espécies bacterianas foram identificadas por testes bioquímicos convencionais e pelo sistema automatizado Vitek 2. O alto nível de resistência aos aminoglicosideos (HLAR), como também o perfil de suscetibilidade a diferentes antimicrobianos foram avaliados pelo método de disco-difusão. Adicionalmente foram determinadas as concentrações inibitórias mínimas (CIM) para estreptomicina e gentamicina pelo método de diluição em ágar. E. faecalis foi a espécie mais prevalente (93,6%) seguido por E. faecium (4,4%). A resistência aos antimicrobianos foi de 2,5% à ampicilina (10ug), 0,5% à vancomicina (30ug), 0,5% à teicoplanina (30ug), 33% ao cloranfenicol (30ug), 2% à nitrofurantoina (300ug), 62,1% à eritromicina (15ug), 64,5% à tetraciclina (30ug), 24,6% à rifampicina (5ug), 30% ao ciprofloxacino (5ug) e 87,2% à quinupristina-dalfopristina (15ug). A prevalência de HLAR no total das cepas estudadas foi de 10,3%, sendo que dentro deste universo 23,6% para gentamicina (120ug) e 37,4% para estreptomicina (300ug). A prevalência de Enterococcus resistentes à vancomicina (ERV) foi muito baixa neste estudo (0,5%).

Identification, antimicrobial resistance and genotypic characterization of Enterococcus spp. isolated in Porto Alegre, Brazil / Identificação, resistência antimicrobiana e caracterização genotípica de Enterococcus spp. isolados em Porto Alegre, Brasil

In the past two decades the members of the genus Enterococcus have emerged as important nosocomial pathogens worldwide. In the present study, we evaluated the antimicrobial resistance and genotypic characteristics of 203 Enterococcus spp. recovered from different clinical sources from two hospitals in Porto Alegre, Rio Grande do Sul, Brazil. The species were identified by conventional biochemical tests and by an automated system. The genetic diversity of E. faecalis presenting high-level aminoglycoside resistance (HLAR) was assessed by pulsed-field gel electrophoresis of chromosomal DNA after SmaI digestion. The E. faecalis was the most frequent specie (93.6 percent), followed by E. faecium (4.4 percent). The antimicrobial resistance profile was: 2.5 percent to ampicillin, 0.5 percent to vancomycin, 0.5 percent teicoplanin, 33 percent to chloramphenicol, 2 percent to nitrofurantoin, 66.1 percent to erythromycin, 66.5 percent to tetracycline, 24.6 percent to rifampicin, 30 percent to ciprofloxacin and 87.2 percent to quinupristin-dalfopristin. A total of 10.3 percent of the isolates proved to be HLAR to both gentamicin and streptomycin (HLRST/GE), with 23.6 percent resistant only to gentamicin (HLR-GE) and 37.4 percent only to streptomycin (HLRST). One predominant clonal group was found among E. faecalis HLR-GE/ST. The prevalence of resistance among beta-lactam antibiotics and glycopeptides was very low. However, in this study there was an increased number of HLR Enterococcus which may be spreading intra and inter-hospital.

Nas últimas duas décadas os membros do gênero Enterococcus emergiram como importantes patógenos nosocomiais ao redor do mundo. No presente estudo, nós avaliamos a resistência antimicrobiana e as características genotípicas de 203 Enterococcus spp. obtidos de diferentes fontes clínicas em dois hospitais de Porto Alegre, Rio Grande do Sul, Brasil. As espécies foram identificadas por testes bioquímicos convencionais e por um sistema automatizado. A diversidade genética de E. faecalis demonstrando resistência à altos níveis de aminoglicosídeos (HLAR) foi avaliada através da análise do DNA cromossômico após digestão com a enzima SmaI, seguido por eletroforese em campo pulsado. O E. faecalis foi a espécie mais freqüente (93,6 por cento), seguido por E. faecium (4,4 por cento). O perfil de resistência antimicrobiana foi: 2,5 por cento para ampicilina, 0,5 por cento para vancomicina, 0,5 por cento para teicoplanina, 33 por cento para cloranfenicol, 2 por cento para nitrofurantoína 66,1 por cento para eritromicina, 66,5 por cento para tetraciclina, 24,6 por cento para rifampicina, 30 por cento para ciprofloxacino e 87,2 por cento para quinupristina-dalfopristina. Um total de 10,3 por cento dos isolados apresentaram HLAR para ambos gentamicina e estreptomicina (HLR-ST/GE), sendo 23,6 por cento resistentes somente a gentamicina (HLR-GE) e 37,4 por cento somente a estreptomicina (HLR-ST). Um grupo clonal predominante foi encontrado em E. faecalis HLR-GE/ST. A prevalência de resistência a antibióticos ²-lactâmicos, e em particular aos glicopeptídeos, foi muito baixa. Entretanto, neste estudo, houve um número crescente de Enterococcus HLAR que podem estar se disseminando intra e interhospitais.

Evaluation of oxacillin and cefoxitin disks for detection of resistance in coagulase negative staphylococci

Coagulase-negative Staphylococcus spp. was considered nonpathogenic until the emergence of multiresistance and the demonstration of their participation as infectious agents. In Brazil, oxacillin resistance may be present in over 80 percent of isolates, and the Clinical and Laboratory Standards Institute standardized a disk-diffusion method to predict this resistance in Staphylococcus. The aim of this study was to evaluate the variability among commercial disks of oxacillin (1 mug) and cefoxitin (30 mug) widely used in clinical laboratories of microbiology, compared with mecA gene and minimum inhibitory concentration (MIC) of oxacillin. The use of oxacillin and cefoxitin disks simultaneously allowed the detection of important differences, particularly, in less frequent species such as S. cohnii, S. haemolyticus, S. saprophyticus, and S. sciuri. Disks of cefoxitin of the brand 2 displayed good correlation with the mecA gene (98.7 percent) and oxacillin MIC (97.8 percent), while major discrepancies were observed using disks of brand 1. One of the critical points in the diffusion disk test is the quality of the disks: the use of better quality disks associated with molecular methods lead to better results to define the best antibiotic therapy.

Extended-spectrum beta-lactamases in Klebsiella spp and Escherichia coli obtained in a Brazilian teaching hospital: detection, prevalence and molecular typing

Este estudo foi desenvolvido para comparar métodos de deteccão e para estimar a prevalência de Klebsiella spp e E.coli produtoras de b-lactamases de espetro ampliado (ESBL) em um Hospital Universitário no sul do Brasil. A correlacão genética, determinada através de método molecular de tipagem, entre as amostras de K. pneumoniae também foi determinada. A producão de ESBL foi investigada em 95 amostras de Klebsiella spp e E.coli obtidas de pacientes no Hospital de Clínicas de Porto Alegre usando-se: medida do diâmetro a zona de inibicão (KB), dupla-difusão de disco (DD), valores de concentracão inibitória mínima da ceftazidima (MIC CAZ), aumento do diâmetro da zona de inibicão com adicão de clavulanato (CAZ/CAC) e a relacão entre o MIC da ceftazidima/MIC ceftazidima com clavulanato (MIC CAZ/CAC). A tipagem molecular foi realizada utilizando-se o método de macrorestricão de DNA e eletroforese em campo pulsado (PFGE). O método KB apresentou as maiores taxas de producão de ESBL (> 70 per center para Klebsiella e 59 per center para E.coli) contrastando com os outros métodos (p< 0,05). Os métodos confirmatórios (DD, MIC CAZ e MIC CAZ/CAC) indicaram a producão de ESBL em 8 a 13 per center de E.coli e em 33 a 40 per center para as espécies de Klebsiella. Portanto, o método KB é útil apenas como método de triagem devido aos diversos resultados considerados falso-positivos. A tipagem molecular realizada em 17 amostras de K.pneumoniae ESBL indicou não existência de relacão clonal. Este estudo encontrou uma boa correlacão entre os métodos confirmatórios de deteccão de ESBL embora os métodos que avaliam a inibicão da enzima pelo clavulanato parecam ser mais específicos. A alta prevalência de Klebsiella ESBL em nosso hospital provavelmente se deve a selecão individual de cepas resistentes do que a transmissão de uma cepa comum.

Antibiotic resistance and molecular typing of Pseudomonas aeruginosa: focus on imipenem

Susceptibility tests by disk diffusion and by E-test and molecular typing by macrorestriction analysis were performed to determine the relatedness of Pseudomonas aeruginosa isolates from three distinct hospitals. The resistance profile of 124 isolates to 8 antimicrobial agents was determined in three different hospitals, in Porto Alegre, Brazil. Frequencies of susceptibility ranged from 43.9 for carbenicillin to 87.7 for ceftazidime. Cross-resistance data of imipenem-resistant isolates indicated that most (70) were also resistant to carbenicillin, although 30 remained susceptible to ceftazidime and cefepime. In general, susceptibility profiles were not able to determine relatedness among isolates of P. aeruginosa. On the other hand, molecular typing by macrorestriction analysis demonstrated high discriminatory power and identified 66 strains among 72 isolates of P. aeruginosa. Imipenem-susceptible isolates were all different. However, identical clones of imipenem-resistant isolates were found in two of the hospitals, despite variable response to other antibiotics. No clustering of infection among the different medical centers was observed. In conclusion, clones of P. aeruginosa did not spread among the different hospitals in our city even though related isolates of imipenem-resistant P. aeruginosa were found.