Frecuencia y susceptibilidad a penicilina y meticilina de aislamientos ambientales de Staphylococcus aureus en un hospital de Cuenca / Frequency and susceptibility to penicillin and methicillin of Staphylococcus aureus environmental isolations at a Cuenca´s hospital

Staphylococcus aureus es un patógeno asociado con infecciones intrahospitalarias comúnmente hallado en las fosas nasales y las manos del personal de salud; así como, en superficies ambientales, las cuales se convierten en potenciales reservorios y vehículos de transmisión de infecciones. En este estudio se analizó la frecuencia y la susceptibilidad a penicilina y meticilina de aislamientos ambientales de S. aureus en un hospital de Cuenca. Se recolectaron 50 muestras (30 de dos quirófanos y 20 de la sala de cuidados intensivos). S. aureus se identificó por pruebas fenotípicas y detección molecular del gen nuc. La susceptibilidad a meticilina y penicilina se determinó por el método de difusión del disco en agar y los genes blaZ y mecA por reacción en cadena de la polimerasa. La frecuencia de S. aureus fue de 6% (3/50 cepas). La resistencia a penicilina y meticilina fue de 66,6% (2/3 cepas). Los genes blaZ y mecA se detectaron en las dos cepas resistentes a penicilina y meticilina. La baja frecuencia de S. aureus puede estar relacionada con los ambientes analizados; ya que, las superficies muestreadas son áreas donde se hace énfasis en la aplicación de protocolos de higiene y desinfección para asegurar una adecuada descontaminación

Staphylococcus aureus is a pathogen associated with intrahospital infections commonly found in the nasal cavities and the hands of health personnel, as well as, on environmental surfaces; which become potential reservoirs and transmission vehicles of infections. In this study the frequency and susceptibility to penicillin and methicillin of environmental isolates of S. aureus in a hospital to Cuenca were analyzed. 50 samples (30 of two operating room and 20 of the intensive care room) were collected. S. aureus was identified by phenotypic tests and molecular detection of the nuc gene. The susceptibility to methicillin and penicillin was determined by agar disc diffusion method and the blaZ and mecA genes by polymerase chain reaction. The frequency of S. aureus was 6% (3/50 strains). Resistance to penicillin and methicillin was 66.6% (2/3 strains). The blaZ and mecA genes were detected in the two strains resistant to penicillin and methicillin. The low frequency of S. aureus may be related to the environments analyzed; because the surfaces sampled are areas where emphasis is placed on the application of hygiene and disinfection protocols for ensure adequate decontamination

Spatial exploration of Streptococcus pneumoniae clonal clustering in São Paulo, Brazil

OBJECTIVES: To examine the spatial distribution of Streptococcus pneumoniae and its clonal patterns collected between 2002 and 2006 in São Paulo, Brazil. METHODS: As part of an observational study in São Paulo city, Brazil, S. pneumoniae isolates routinely cultured from blood, respiratory specimens, or cerebrospinal and other profound fluids were selected. Additionally, only isolates with either penicillin (PEN) intermediate (I) or resistant (R) status on routine antibiogram were included, in order to obtain a higher probability of clonal isolates. A single I/R S. pneumoniae isolate per patient was included and submitted to genotypic determination by pulsed field gel electrophoresis (PFGE). Minimum inhibitory concentrations (MICs) were determined for the isolates by Etest® to PEN and other antimicrobials. Each isolate was geocoded in a digital map. The Kernel function and ratio methods between total isolates vs. clones were used in order to explore possible cluster formations. RESULTS: Seventy-eight (78) S. pneumoniae community isolates from two major outpatient centers in São Paulo, Brazil, were selected from the databank according to their penicillin susceptibility profile, i.e. R or I to penicillin assessed by oxacillin disc diffusion. Of these, 69 were submitted to PFGE, 65 to MIC determination, and 48 to spatial analytical procedures. Preliminary spatial analysis method showed two possible cluster formation located in southwest and southeast regions of the city. CONCLUSION: Further analyses are required for precisely determining the existence of S. pneumoniae clusters and their related risk factors. Apparently there is a specific transmission pattern of S. pneumoniae clones within certain regions and populations. GIS and spatial methods can be applied to better understand epidemiological patterns and to identify target areas for public health interventions.

Clinical analysis of 39 patients with carbapenem-resistant Klebsiella pneumoniae infection / 中华传染病杂志

Objective To investigate the clinical characteristics, risk factors and prevention measures of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection. Methods Thirty-nine cases whose CRKP isolation and culture were positive and who were confirmed with nosocomial infection in 2nd affiliated hospital medical school of Zhcjiang University between July 2006 and July 2008 were retrospectively investigated. Results There were 22 (56.4%) sputum specimens among CRKP samples. The average age of the patients was 64.0 years old and the average length of staying in hospital was 80.8 days. There wcre 36 patients who had been in intensive care unit (ICU) within 2 weeks and 26 were conscious disturbance,38 received urethral catheterization, 34 inserted with central venous catheter, 32 received tracheal intubation and 30 assisted with mechanical ventilation. There were 27 (69. 2 % ) patients who were co-infected with other bacteria and 8 were co-infccted with fungi. The mortality was 46. 2% in patients with CRKP infection. Before CRKP-positive culture, 27 (69.2%)experienced ＞4 kinds of antibiotics with the majority of β-lactams/β-lactamase inhibitors and carbapenems.Conclusions CRKP infection frequently occurrs in elder and patients who prolonged stay in hospital,especially patients in ICU. Invasive procedures could increase the infection opportunities.

Analysis of cefoxitin-sensitive, penicillin-resistant Staphylococcus tested by disk diffusion method / 中华检验医学杂志

Objective To evalue the ability of detecting the resistance of cefoxitin-sensitive,penicillin-resistant Staphylococcus by different methods and analyze the antibiotic susceptibility spectrum of coagulase-negative Staphylococcus which are non-mecA-mediated oxacillin resistance. Methods All the isolates were collected from Huashan hospital between 2007 and 2009. The isolates were recovered from various clinical sources, including respiratory tract, urine, secretion and sterile fluids samples. The oxacillin susceptibility of Staphylococcus aureus was determined by cefoxitin disk diffusion test, cefoxitin MIC test,oxacillin disk diffusion test and oxacillin MIC test Likewise, the oxacillin susceptibility of coagulasenegative Staphylococcus was determined by cefoxitin disk diffusion test and oxacillin MIC test. All the isolates with sensitive to cefoxitin were screened for the mec A gene by PCR Finally, the MIC of non-mecA-mediated oxacillin-resistant Staphylococcus were determined. Results Among 255 cefoxitin disk diffusion test sensitive and penicillin-resistant Staphylococcus aureus, 6 isolates were intermediated to oxacillin and 4 were resistant by oxacillin disk diffusion test, but all the isolates were sensitive by the cefoxitin disk diffusion test,cefoxitin MIC test and oxacillin MIC test. Among 75 cefoxitin disk diffusion test sensitive and penicillin-resistant coagulase-negative Staphylococcus, 16 isolates were resistant to oxacillin by oxacillin MIC method and 4 carried mecA gene. Among 12 non-mecA-mediated oxacillin-resistant Staphylococcus, the susceptible isolates of gentamicin is 10, clindamycin is 8, ciprofloxacin is 11, erythrornycin is 6, trimethoprim/sulfamethoxazo]e is 11 ,and cephalosporins, teicoplaninl, vancomycin, piperacillin/tazobactam, tetracycline are all 12. Conclusions The cefoxitin disk diffusion test can reliably predict mecA-mediated oxacillin resistant Staphylococcus aureus. It would be best to combine cefoxitin disk diffusion test and oxacillin MIC test to improve accuracy of detection of mecA-mediated oxacillin resistant coagulase-negative Staphylococcus.Furthermore, infections due to the non-mecA-mediated oxacillin resistant coagulase-negative Staphylococcus can be treated by penicillinase-stable penicillins, β-lactam/β-lactam inhibitor combinations, relevant cephems and carbapenems.

Alta prevalência de crianças portadoras de Streptococcus pneumoniae resistentes à penicilina em creches públicas / High prevalence of children colonized with penicillin-resistant Streptococcus pneumoniae in public day-care centers

OBJETIVOS: Investigar a prevalência de Streptococcus pneumoniae (pneumococos) na nasofaringe de crianças sadias atendidas em creches municipais da cidade de Umuarama (PR). Avaliar a susceptibilidade aos antimicrobianos dos pneumococos isolados. MÉTODOS: Secreção da nasofaringe de 212 crianças foi coletada no período de abril a outubro de 2008. Após semeadura dos espécimes em ágar sangue e incubação a 37 °C por 24-48 horas, as colônias suspeitas de pertencerem a S. pneumoniae foram identificadas pela α-hemólise, sensibilidade à optoquina e bile solubilidade. A susceptibilidade à penicilina foi investigada pelos testes de disco-difusão e de diluição. A susceptibilidade aos demais antimicrobianos indicados no tratamento das infecções pneumocócicas foi realizada por disco-difusão RESULTADOS: A prevalência de pneumococos na nasofaringe foi de 43,4 por cento (92/212), sendo maior em crianças com idade entre 2 e 5 anos (p = 0,0005). Não houve diferença significativa entre os sexos. Resistência intermediária e resistência plena à penicilina foram encontradas respectivamente em 34,8 (32/92) e 22,8 por cento (21/92) dos isolados. Sessenta e sete amostras (72,8 por cento) foram resistentes ao sulfametoxazol-trimetoprim, oito (8,7 por cento) à eritromicina e seis (6,5 por cento) à tetraciclina. Uma amostra apresentou resistência à clindamicina (1,1 por cento), e outra ao cloranfenicol (1,1 por cento). Todas as amostras foram sensíveis a levofloxacina, ofloxacina, rifampicina, telitromicina, linezolide e vancomicina. Nove amostras foram consideradas multirresistentes, por apresentarem resistência a três ou mais classes de antimicrobianos. CONCLUSÕES: O presente estudo registrou uma alta prevalência de crianças portadoras sadias de amostras de S. pneumoniae resistentes à penicilina que podem constituir importantes reservatórios desse patógeno na comunidade.

OBJECTIVES: To investigate the prevalence of Streptococcus pneumoniae (pneumococci) in the nasopharynx of healthy children enrolled in public day-care centers of the municipality of Umuarama, state of Paraná, Brazil. The susceptibility of the pneumococcal strains to antimicrobial agents was also studied. METHODS: Nasopharyngeal specimens from 212 children were collected from April to October 2008. After the specimens were seeded in blood agar and incubated at 37 °C for 24-48 hours, the colonies suspected of belonging to S. pneumoniae were identified using α-hemolysis, optochin sensitivity, and bile solubility test. Penicillin susceptibility was investigated using the disk diffusion and dilution tests. Susceptibility to the other antimicrobial agents indicated for the treatment of pneumococcal infections was investigated using the disk diffusion test. RESULTS: The prevalence of nasopharyngeal pneumococci was 43.4 percent (92/212), with higher rates in children between 2 and 5 years old (p = 0.0005). There was no significant difference between sexes. Intermediate and full resistance to penicillin were found in 34.8 (32/92) and 22.8 percent (21/92) isolates, respectively. Sixty-seven strains (72.8 percent) were resistant to sulfamethoxazole-trimethoprim, eight (8.7 percent) were resistant to erythromycin, and six (6.5 percent) to tetracycline. One strain was resistant to clindamycin (1.1 percent) and another was resistant to chloramphenicol (1.1 percent). All strains were sensitive to levofloxacin, ofloxacin, rifampicin, telithromycin, linezolid, and vancomycin. Nine strains were considered multiresistant because they were resistant to three or more classes of antimicrobial agents. CONCLUSIONS: The present study detected a high prevalence of healthy children colonized with penicillin-resistant S. pneumoniae strains who may be important reservoirs of this pathogen in the community.

Distribución de serotipos y patrón de sensibilidad in vitro a diferentes antibióticos de cepas de Streptococcus pneumoniae obtenidas de niños menores de 15 años en aislamientos invasores en el departamento de Risaralda, 1999 a 2004 / Serotype Distribution and in Vitro Antibiotic Sensitivity of Streptococcuspneumoniae Strains from Invasive Disease Isolates among Children Under 15Years Old, in Risaralda, Colombia, 1999 to 2004

Objetivo. Identificar las cepas prevalecientes de Streptococcus pneumoniae causantes de enfermedad invasiva y su patrón de sensibilidad a la penicilina en niños menores de 15 años que habitan el departamento de Risaralda. Método. Análisis descriptivo a partir de muestras de fluidos estériles analizados por el Instituto Nacional de Salud dentro de su programa de vigilancia epidemiológica del neumococo, y provenientes de niños menores de 15 años del departamento de Risaralda durante los años 1999 a 2004. Resultados. Las cepas prevalentes de S. pneumoniae en Risaralda no son diferentes a las halladas en otras regiones del país. La tasa de resistencia del neumococo aislado en fluidos estériles por ciento - 26,2 por ciento). Para menores de 5 años fue de 35 por ciento. No hay datos de sensibilidad a las cefalosporinas de tercera generación. Conclusión. La implementación de un programa de vacunación contra neumococo en el departamento del Risaralda prevendría en un alto porcentaje la posibilidad de adquirir enfermedad invasiva. Dado el alto índice de resistencia a la penicilina, los esquemas antibióticos empíricos para enfermedad invasiva por neumococo en menores de 5 años deben incluir la vancomicina y las cefalosporinas de tercera generación hasta que se obtengan cultivos definitivos

AbstarctObjective: To identify the most prevalent sero-types and in vitro antimicrobial susceptibility topenicillin and other antibiotics in children under 15years old who have Streptococcus pneumoniaeinvasive disease and live in the department ofRisaralda (Colombia). Method: We reviewed thedata analyzed by the Instituto Nacional de Saludfrom S. pneumoniae sterile fluid's isolated during5 years (1999 to 2004). Results: Most prevalentserotypes of S. pneumoniae in Risaralda are notdifferent from others departments of Colombia. Itsresistance to penicillin was 22% for all childrenand 35% for children under 5 years old. 7.5% ofthe isolates had intermediated sensitivity toceftriaxone. Conclusions: An immunization pro-gram in children under 5 years old in Risaraldawould prevent a lot of cases of invasive disease byS. pneumoniae. The empiric treatment of S. pneu-moniae Invasive Disease in children under 5 yearsold in Risaralda would include vancomycin plus athird generation cephalosporins until antibiogramis developed

Penicillin Resistant Distribution and in-vitro Susceptibility of Oral Antibiotics against Streptococcus pneumoniae, isolated from Pediatric Patients with Community- Acquired Respiratory Infections in Korea / 소아과

PURPOSE: S. pneumoniae is one of major pathogens of community-acquired respiratory infections. The rate of antibiotic resistance to this organism has increased, and resistance to multiple antimicrobial agents in a single strain of S. pneumoniae may compromise the efficacy of empiric antimicrobial treatment commonly used for respiratory infections. We did this study to find out the penicillin resistant distributions and oral antibiotics susceptibility patterns against S. pneumoniae, isolated from pediatric patients with community-acquired respiratory infections in Korea. METHODS: One hundred fifty six pneumococcal isolates obtained from pediatric patients with community-acquired respiratory infections such as acute otitis media(AOM), sinusitis and pneumonia between May 2000 to June 2003. And MICs of penicillin and oral antibiotics(amoxicillin, amoxicillin- clavulanate, cefaclor) were performed by broth microdilution methods according to the NCCLS(2003a). RESULTS: Seventy eight percent of the isolates were resistant to penicillin. The isolates, collected from AOM patients showed the highest penicillin resistance(92.7%). The resistant rates of amoxicillin (16.7%) and amoxicillin-clavulanate(9.6%), based on susceptibility breakpoints established by the NCCLS, were markedly lower than these of penicillin. But, the resistant rate of cefaclor was very high, above 95%. CONCLUSION: We concluded that pneumococci isolated from study cases may be one of the world's highest penicillin resistant rates. But, amoxicillin and amoxicillin-clavulanate can be used as a first- line antibiotics. Finally, we hope that a continuous surveillance study to monitor resistant patterns of pneumococcal respiratory infections will be needed for the standard guidelines of empiric antibiotic treatment.

Epidemiological Study of Pneumococcal Nasal Carriage and Serotypes Among Korean Children / 소아과

PURPOSE: The aim of this study was to determine the prevalence of pneumococcal nasal carriage and confirm the distribution of pneumococcal capsular serotypes in Korean children below aged 5 years old. Another reason this study was performed was to identify the theoretical coverage by seven valent conjugate pneumococcal vaccine, and confirm the penicillin resistant rate. METHODS: This study included 213 children, who visited out patient clinic or were hospitalized in six hospitals between August 2001 and April 2002. Nasopharyngeal swabs and cultures for S. pneumoniae were performed. Serotyping of isolated samples was performed by the Quellung reaction at the Statens Seruminstitut in Copenhagen. Penicillin MICs were determined by the agar dilution method, and interpreted according to the NCCLS guide line. RESULTS: The prevalence of pneumococcal nasal carriage rate in this study was 34.3%. A total of 31 of 73 isolates(42.5%) had intermediate resistance to penicillin, and 29 of 73 isolates(39.7%) showed a high resistance to penicillin. The predominant serotype of the S. pneumoniae isolates was 23F(22%), and the percentages of vaccine serotypes(46.6%) and associated serotypes(37%) which belong to the seven-valent pneumococcal conjugate vaccine were 83.6%. The resistance pattern of pneumococcal isolates to penicillin was different among the serotypes. CONCLUSION: Pneumococcal isolates from nasal colonization of Korean children showed a high penicillin resistant rate. We assumed that newly developed seven-valent pneumococcal conjugate vaccine may offer a high theoretical coverage for the isolated strains.

Therapeutic Efficacy of Meropenem for Treatment of Experimental Penicillin-Resistant Pneumococcal Meningitis

With the widespread emergence of antimicrobial resistance, combination regimens of ceftriaxone and vancomycin (C+V) or ceftriaxone and rifampin (C+R) are recommended for empirical treatment of pneumococcal meningitis. To evaluate the therapeutic efficacy of meropenem (M), we compared various treatment regimens in arabbit model of meningitis caused by penicillin-resistant Streptococcus pneumoniae (PRSP). Therapeutic efficacy was also evaluated by the final bacterial concentration in the cerebrospinal fluid (CSF) at 24 hr. Each group consisted of six rabbits. C+V cleared the CSF at 10 hr, but regrowth was noted in 3 rabbits at 24 hr. Meropenem monotherapy resulted in sterilization at 10 hr, but regrowth was observed in all 6 rabbits at 24 hr. M+V also resulted in sterilization at 10 hr, but regrowth was observed in 2 rabbits at 24 hr. M+V was superior to the meropenem monotherapy at 24 hr (reduction of 4.8 vs. 1.8 log10 cfu/mL, respectively; p=0.003). The therapeutic efficacy of M+V was comparable to that of C+V (reduction of 4.8 vs. 4.0 log10 cfu/mL, respectively; p=0.054). The meropenem monotherapy may not be a suitable choice for PRSP meningitis, while combination of meropenem and vancomycin could be a possible alternative in the treatment of PRSP meningitis.

Prevalence and Clinical Outcome of Penicillin-resistant Pneumococcal Pneumonia / 결핵

BACKGROUND: The incidence of penicillin-resistant streptococcus pneumoniae(PRSP) accounts for almost 70% of all pneumococcal pneumonia cases in Korea. It is still unclear as to whether the efficacy of penicillin or equally active beta-lactam agents is compromised in PRSP pneumonia. This study investigated the prevalence of PRSP in community-acquired pneumonia and its clinical course. METHODS: A total of 42 patients with community-acquired pneumococcal pneumonia were evaluated from July 1999 to May 2001. The cultured strains of Streptococcus pneumoniae were divided into susceptible, intermediately resistant, and resistant strains by an E-test, and the effect of the clinical course was investigated. RESULTS: From a total of 42 patients, 22 (52.4%) patients had an intermediate resistance (MIC 0.1-1 microgram/ml) and six (14.3%) showed a high resistance (MIC> or =2.0 microgram/ml) with current penicillin susceptibility categories. However, according to the classification of the DRSPTWG (Drug Resistant Streptococcus pneumoniae Therapeutic Working Group), there were 11 cases (26.2%) of intermediate resistance and no case of high resistance. Under empirical antimicrobial treatment, there was no difference in the clinical outcome between the penicillin susceptible and resistant group. CONCLUSION: The clinical outcome of PRSP pneumonia with empirical therapy was acceptable. These results suggest that the current MIC breakpoint for penicillin resistance in Streptococcus pneumoniae has been set at a very low level and penicillin resistance according to the NCCLS classification does not significantly influence the outcome of the empirical treatment for pneumococcal pneumonia.

Antimicrobial Susceptibilities of Viridans Streptococci Isolated from Blood Cultures during Recent Period / 임상검사와정도관리

BACKGROUND: Viridans group streptococci (VGS) are being increasingly reported as pathogens causing septicemia in neutropenic and other immunocompromised patients since 1980s. In the past, VGS were nearly uniformly susceptible to beta-lactam antimicrobial agents, aminoglycosides, tetracyclines, and macrolides. Several recent published studies, however, indicate that antimicrobial resistance may be emerging as a problem with VGS. The purpose of this study was to determine the antimicrobial susceptibility of VGS strains isolated from blood cultures in recent period. METHODS: A total of 45 consecutive strains of VGS isolated from blood cultures between May 2001 and March 2002 at Wonju Christian Hospital were tested for antimicrobial susceptibility. Identification of VGS were performed by API Strep 32(bioMerieux sa, Marcy-l'Etoile, France) commercial kit. Antimicrobial susceptibility tests were done by NCCLS recommended disk diffusion method and penicillin MICs were determined by E test. RESULTS: Among the 45 VGS strains, frequently isolated organisms were Streptococcus mitis (31.1%), Streptococcus oralis (17.8%), Streptococcus constellatus (11.1%), and Streptococcus anginosus (8.9%). Overall intermediate-and resistant rates to antimicrobial agents of VGS were as follows: penicillin; 26.7% and 8.9%, erythromycin; 4.4% and 28.9%, clindamycin 2.2% and 22.2%, and ceftriaxone; 4.4% and 6.7%, respectively. Resistant rates of Streptococcus mitis and Streptococcus oralis were as follows: penicillin; 50% vs 50%, erythromycin 43% vs 37%, clindamycin 21% vs 37%, and ceftriaxone 7% vs 25%, respectively. CONCLUSIONS: These results indicate the species-related variability of susceptibility among VGS isolated from blood in recent period. In addition to S. mitis, S. oralis also displayed high rates of resistance to penicillin, macrolides, and ceftriaxone. The difference in susceptibilities between species of VGS indicates the importance of accurate identification and the need for continuing monitoring of antimicrobial resistance.

Penicillin-resistant Aerococcus viridans Bacteremia Associated with Granulocytopenia

Aerococcus viridans, a catalase-negative gram-positive coccus rarely causing bacteremia, was isolated from blood cultures of a 52-yr-old man under the gran-ulocytopenic condition. The isolate showed the typical characteristics of A. viridans, i.e., tetrad arrangements in gram stain, positive pyrrolidonyl aminopeptidase (PYR) and negative leucine aminopeptidase (LAP) reactions, and no growth at 45 degrees C.The isolate was revealed to be highly resistant to penicillin, erythromycin, clindamycin, and ceftriaxone, although most strains of A. viridans isolated from the previously reported patients were susceptible to penicillin and other commonly used antibiotics. Even though A. viridans is rarely associated with human infections, it could be a potential causative agent of bacteremia, especially in immunocompromised patients.

Estafilococos y enterococos: ¿amenazas a la salud pública?: epidemiología y mecanismos de resistencia a los antibióticos / Staphylococci and enterococci: threats to public health?: epidemiology and mechanisms of resistance to antibiotics

La resistencia a los antimicrobianos se está convirtiendo en un problema de salud emergente. Las especies de estafilococos y enterococos son microorganismos causantes de múltiples y frecuentes infecciones en el ser humano, principalmente a nivel nosocomial. El Staphylococcus aureus ha adquirido mecanismos de resistencia a la penicilina, a las penicilinas resistentes a las penicilinasas -meticilina- (SAMR), y recientemente, a la vancomicina (VISA). El enterococo es intrínsecamente resistente a gran variedad de agentes antimicrobianos y ha adquirido resistencia a betalactámicos, aminoglicósidos y glicopéptidos. Múltiples mecanismos explican la adquisición, desarrollo y diseminación de la resistencia. Existen en el momento pocas alternativas para tratar infecciones producidas por microorganismos resistentes y las medidas en el momento se deben dirigir al control del uso de antibióticos y prevención de la diseminación. Se realiza una revisión de la epidemiología, mecanismos de resistencia, opciones de tratamiento y medidas de control de estos microorganismos.

Antimicrobial resistance is becoming an emerging health problem. Gram-positive cocci are bacterias which cause multiple and frequent infections in the human being, specially nosocomialleveL Staphylococcus aureus has acquired resistance mechanisms to penicillins,methicillin (MRSA) and recently to vancomycin (VISA). Enteroccocus spp is intrincically resistant to a great variety of antimicrobial agents and it has acquired resistance to betalactamics, aminoglycosides and glycopeptides. Multiple mechanisms explain theacdquisition, development and spread of resistance. At the moment there are a few alternatives to treat infections produced by resistant bacterias and the measurements should be directed to the control in the antibiotics use and infection control practice. This reviewattempts to point out the edpidemiology, resistance mechanisms treatment options and prevention means of these microorganisms.

Estafilococos multirresistentes: uso del disco de oxacillín como marcador de resistencia a antibióticos

Se estudió la susceptibilidad in vitro de cepas pertenecientes al género Staphylococcus frente a diferentes antibióticos y se hizo énfasis en la vancomicina y la penicilina a partir del grado de resistencia presentado frente al oxacillín. Se utilizaron 200 cepas de estafilococos, 100 de ellas pertenecientes a la especie Staphylococcus aureus y otras 100 a estafilococos coagulasa negativos. El origen de las cepas fue tanto intrahospitalario como comunitario. Se observó resistencia notable al oxacillín, altísima frente a la penicilina e incipiente a la vancomicina por parte de las cepas estudiadas, sobre todo en estafilococos coagulasa negativos. Las cepas oxacillín-resistentes mostraron los valores más altos y un amplio espectro de resistencia a los antibióticos.

The susceptibility in vitro of strains belonging to the genus Staphylococcus was studied by using different antibiotics. Emphasis was made on vancomycin and penicillin based on the degree of resistance to oxacillin. 200 strains of staphylococci were used. l00 of them belonging to the Staphylococcus aureus species and the other 100 to coagulase-negative staphylococci. The strains had an intrahospital and community origin. The rates of resistance observed among the studied strains, mainly the coagulase-negative staphylococci, were as follows: significant to oxacillin, very high to penicillin and incipient to vancomycin. The oxacillin-resistant strains showed the highest values and a wide spectrum of resistance to antibiotics.

Clinical Characteristics of Pneumococcal Bacteremia in Adults: The Effect of Penicillin Resistance on the Mortality of Patients with Pneumococcal Bacteremia / 결핵

BACKGROUNDS: The advent of penicillin has led to the marked reduction in the mortality from pneumococcal bacteremia, however, the mortality is still relatively high in this post-antibiotic era. Actually the prevalence of infection due to penicillin-resistant penumococci is increasing worldwide, and it is especially high in Korea due to irrelevant use of antibiotics. So, the high mortality of pneumococcal sepsis might be related to the emergence of penicillin-resistant strains, however, many other antibiotics, which eradicate pneumococci effectively, are available in these days. This has led us to suspect the role of penicillin- resistance in the high mortality rate. In this study, we evaluated the effect of penicillin resistance on the mortality of patients with penumococcal bacteremia. METHODS: The study population consisted of 50 adult patients with penumococcal bacteremia who were admitted between Jan, 1990 and July, 1997. Medical records were analyzed retrospectively. RESULTS: Most of the patients (96%) had underlying diseases. The most common local disease associated with pneumococcal bacteremia was pneumonia (42%), which was followed by spontaneous bacterial peritonitis (14%), cholangitis (10%), meningitis (8%), liver abscess (4%), pharyngotonsillitis (4%), sinusitis (2%) and cellulitis (2%). While the overall case-fatality rate in this study was 24%, it was higher when peumococcal bacteremia was associated with pneumonia (42%) or meningitis (50%). The rate of penicillin resistance was 40%, which was increased rapidly from 1991. The rate of penicillin resistance was significantly higher in patients with the history of recent antibiotics use and hospitalization within 3 months respectively. The clinical manifestations, that is, age, severity of underlying diseases, nosocomial infection, associated local diseases, and the presence of shock or acute renal failure were not statistically different between the patients with penicillin- resistant and -sensitive pneumococcal bacteremia. The mortality of patients infected with penicillin-resistant pneumococci was not statistically different from those with penicillin-sensitive pneumococcal bacteremia. CONCLUSION: Penicillin resistance is not associated with high mortality in adult patients with pneumococcal bacteremia. As the overall mortality is high, active penumococcal vaccination is recommended in patients with high risk of infection.

Sequencing Analysis of Penicillin-Binding Protein 2B Gene of Streptococcus pneumoniae Isolated in Korea / 대한임상병리학회지

BACKGROUND: The resistance of Streptococcus pneumoniae to penicillin has been rapidly increasing during the recent three decades. In Korea, we found the incidence of penicillin resistance (PR) to pneumococci was 81% for the clinical isolates in our hospital, and 89% for the colonizing isolates of day-care center around Seoul. Alterations in penicillin-binding protein (PBP) 2B gene have been known to be associated with a resistance to penicillin. We tried to reveal the characteristics of PR of Korean pneumococcal strains through sequencing analysis of PBP 2B gene. METHODS: We determined the nucleotide sequences of 346 bp of a variable region among PBP 2B gene for 12 PR strains and 6 penicillin susceptible (PS) strains isolated in Korea. Phylogenetic tree using PAUP program was made to compare our DNA sequences with those of South African strains. RESULTS: Sequence homology of PS strains was ranged from 99.4% to 100% in Korean PS strain compared to reference strain, R6, except one strain (93.9%). PR strains showed homology of 95.1% to 100% compared to the South African 56762 strain. Phylogenetic analysis based on 346 bp of PBP 2B gene showed that Korean and South African strains formed different monophyletic groups according to the PR/PS patterns. Five specific amino acid changes compared to the PS R6 strain in the position 228, 232, 233, 244, and 261 were noted with a decreased hydrophilicity by Kyte-Doolittle assay. CONCLUSIONS: Our data suggest that the amino acid changes in the PBP 2B are associated with PR in S. pneumoniae, and that a part of Korean PR strains might be originated from a South African PR strain.

Clinical Characteristics of Bacteremic Pneumococcal Diseases Due to Penicillin-Resistant Streptococcus pneumoniae / 감염

BACKGROUND: The emergence of penicillin-resistant Streptococcus pneumoniae (PRSP) poses serious therapeutic problem in clinical practice, especially in cases with bacteremia or meningitis. METHODS: To investigate clinical characteristics of bacteremic pneumococcal diseases due to PRSP, we retrospectively analyzed 41 cases with documented bacteremic diseases seen in a tertiary care hospital between 1989 and 1994. RESULTS: Agar dilution test of 41 strains isolated showed that 68.3% of S. pneumoniae were PRSP [high-level resistance(R) 56.1%, intermediate resistance (I) 12.2%]. High-level resistant strains were not susceptible to other beta-lactam agents, whereas isolates of penicillin-susceptible S. pneumoniae (PSSP) were uniformly susceptible to all beta-lactam agents. Predominant serogroup of PRSP were 19, 23, and 6. Bacteremic diseases caused by PRSP included pneumonia (22), meningitis (5), peritonitis (3), acute otitis media (2), acute tonsillitis (2), endocarditis (1), pyelonephritis (1), and primary bacteremia (5). Children were more likely to be infected with PRSP with high-level or intermediately resistant strains than were adults (P=0.0001), but no differences were seen between PRSP and PSSP regarding sex, previous antibiotic history, previous hospitalization, and underlying immunocompromised conditions. Most cases were community-acquired (R 78.3%, I 60%, S 61.5%). Fatality rates of patients infected with PRSP were not different significantly from PSSP (22.6% vs. 30%). However, most fatal cases had underlying immunocompromised conditions. CONCLUSION: PRSP is widely prevalent in Korea and shows resistance to most antibiotics. It causes community-acquired bacteremic diseases with poor outcomes, but there was no difference in mortality between patients infected with PRSP and PSSP. Pediatric age was the only risk factor for penicillin resistance.