RESUMEN

Molecular and morphological methods were evaluated to distinguish between Haemonchus contortus and Haemonchus placei species. A total of 141 H. contortus and 89 H. placei male adult specimens collected from artificially infected lambs were identified individually by PCR analysis, using a species-specific primer pair. These PCR results were used as gold standard for Haemonchus spp. identification. Haemonchus placei presented higher mean spicule and barb lengths than H. contortus (P<0.05). However, some measurements overlapped. For this reason, a discriminate function did not allow the correct identification of 13 H. contortus and one H. placei specimen. The sheath tail length of the third stage larvae (L3), which comprises the distance between the tip of the larval tail and the end of the sheath tail, were measured. Only three of the 485 H. placei larvae (0.619%) had a sheath tail shorter than 85 µm, while only four of the 500 H. contortus larvae (0.8%) presented a sheath tail longer than 85 µm. The results indicated that 6.09% of the male adult specimens would be misclassified based on the discriminate function, while only 0.71% of infective larvae would be misclassified. Therefore, identification of L3 can be used as the first method to indicate the presence of H. placei and/or H. contortus in a population of domestic ruminants.

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Métodos moleculares e morfológicos foram avaliados para a identificação de Haemonchus contortus e Haemonchus placei. No total, 141 H. contortus e 89 H. placei machos adultos, obtidos de cordeiros artificialmente infectados, foram identificados individualmente por PCR com o emprego de um par de “primers” espécie-específico. Esses resultados da análise por PCR foram considerados como padrão para a identificação das espécies de Haemonchus. Haemonchus placei apresentou valores médios de espículos e ganchos superiores aos de H. contortus (P<0,05). Entretanto, houve sobreposição de alguns valores. Por essa razão, a função discriminante não permitiu a identificação correta de 13 exemplares de H. contortus e de um, de H. placei. Foi medida a cauda da bainha de larvas infectantes (L3), que compreende a distância entre a ponta da cauda da larva e a ponta da cauda da bainha. Apenas três das 485 L3 de H. placei (0,619%) apresentaram a cauda da bainha com medida inferior a 85 µm e somente em quatro das 500 L3 de H. contortus (0,8%) essa medida foi superior a 85 µm. Os resultados demonstraram que 6,09% dos machos adultos seriam identificados erroneamente com base na função discriminante, enquanto a identificação incorreta de L3 seria de apenas 0,71%. Portanto, a identificação de L3 pode ser utilizada como método inicial para indicar a presença de H. placei e/ou H. contortus em uma população de ruminantes domésticos.

Asunto(s)

Adolescente , Adulto , Niño , Humanos , Persona de Mediana Edad , Aminoaciltransferasas , Proteínas Bacterianas , Hexosiltransferasas , Peptidil Transferasas , Resistencia a las Penicilinas/genética , Infecciones Neumocócicas/microbiología , Streptococcus pneumoniae/genética , Alelos , Proteínas Portadoras/genética , Cefotaxima/farmacología , Cefalosporinas/farmacología , Enfermedades Transmisibles Emergentes/epidemiología , ADN Bacteriano/análisis , Electroforesis en Gel de Campo Pulsado , Pruebas de Sensibilidad Microbiana , Muramoilpentapéptido Carboxipeptidasa/genética , Proteínas de Unión a las Penicilinas , Infecciones Neumocócicas/epidemiología , Streptococcus pneumoniae/clasificación , Streptococcus pneumoniae/efectos de los fármacos , Estados Unidos/epidemiología

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen that has emerged over the last four decades, causing both nosocomial and community-acquired infections. Rapid and accurate detection of methicillin resistance in S. aureus is important for the use of appropriate antimicrobial therapy and for the control of nosocomial spread of MRSA strains. We evaluated the efficiency of conventional methods for detection of methicillin resistance such as the disk diffusion, agar dilution, oxacillin agar screen test, and the latex agglutination test MRSA-Screen latex, in 100 isolates of S. aureus, 79 mecA positive and 21 mecA negative. The MRSA-Screen latex (Denka Seiken, Niigata, Japón), is a latex agglutination method that detects the presence of PLP-2a, product of mecA gene in S. aureus. The PCR of the mecA gene was used as the "gold standard" for the evaluation of the different methods tested. The percentages of sensitivity and specificity were as follows: disk difusión 97 and 100%, agar dilution 97 and 95%, oxacillin agar screen test 100 and 100%, and MRSA-Screen latex, 100 and 100 %. All methods presented high sensitivity and specificity, but MRSA-Screen latex had the advantage of giving a reliable result, equivalent to PCR, in only 15 minutes.

Asunto(s)

Pruebas de Fijación de Látex , Resistencia a la Meticilina , Pruebas de Sensibilidad Microbiana/métodos , Staphylococcus aureus/efectos de los fármacos , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Proteínas Portadoras/análisis , ADN Bacteriano/genética , Hexosiltransferasas/análisis , Resistencia a la Meticilina/genética , Muramoilpentapéptido Carboxipeptidasa/análisis , Proteínas de Unión a las Penicilinas , Peptidil Transferasas/análisis , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Staphylococcus aureus/genética

RESUMEN

Staphylococcus aureus meticilino-resistente (MRSA) es un patógeno que ha emergido en las últimas cuatro décadas causando tanto infecciones nosocomiales como de la comunidad. La rápida y precisa detección de MRSA es relevante para guiar una apropiada terapia antibiótica y evitar la diseminación nosocomial de MRSA.En este trabajo se evaluó la eficiencia de métodos convencionales para la detección de meticilino-resistencia como difusión por discos, CIM en medio sólido, screening de oxacilina, y el nuevo test de aglutinación MRSA-Screen latex sobre 100 aislamientos de S. aureus, 79 mecA positivos y 21 mecA negativos. El test de aglutinación MRSA-Screen latex (Denka Seiken, Niigata, Japón) detecta la presencia de la PLP-2a, producto del gen mecA en cepas de S. aureus. La detección del gen mecA por PCR se utilizó como gold standard para comparar los resultados de los diferentes métodos. La sensibilidad y especificidad fueron 97 y 100 % para el método de difusión, 97 y 95 % para la CIM en medio sólido, 100 y 100 % para el screening de oxacilina y 100 y 100 % para MRSA-Screen latex. Todos los métodos presentaron alta sensibilidad y especificidad, pero el “MRSA-Screen latex” mostró la ventaja de poder brindar un resultado confiable, equivalente a la PCR, en sólo 15 minutos.

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Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen that has emerged over the last four decades, causing both nosocomial and community-acquired infections. Rapid and accurate detection of methicillin resistance in S. aureus is important for the use of appropriate antimicrobial therapy and for the control of nosocomial spread of MRSA strains. We evaluated the efficiency of conventional methods for detection of methicillin resistance such as the disk diffusion, agar dilution, oxacillin agar screen test, and the latex agglutination test MRSA-Screen latex, in 100 isolates of S. aureus, 79 mecA positive and 21 mecA negative. The MRSA-Screen latex (Denka Seiken, Niigata, Japón), is a latex agglutination method that detects the presence of PLP-2a, product of mecA gene in S. aureus. The PCR of the mecA gene was used as the “gold standard” for the evaluation of the different methods tested. The percentages of sensitivity and specificity were as follows: disk difusión 97 and 100 %, agar dilution 97 and 95 %, oxacillin agar screen test 100 and 100 %, and MRSA-Screen latex, 100 and 100 %. All methods presented high sensitivity and specificity, but MRSA-Screen latex had the advantage of giving a reliable result, equivalent to PCR, in only 15 minutes.

Asunto(s)

Pruebas de Fijación de Látex , Resistencia a la Meticilina , Pruebas de Sensibilidad Microbiana/métodos , Staphylococcus aureus/efectos de los fármacos , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Proteínas Portadoras/análisis , ADN Bacteriano/genética , Hexosiltransferasas/análisis , Resistencia a la Meticilina/genética , Muramoilpentapéptido Carboxipeptidasa/análisis , Proteínas de Unión a las Penicilinas , Reacción en Cadena de la Polimerasa , Peptidil Transferasas/análisis , Sensibilidad y Especificidad , Staphylococcus aureus/genética

RESUMEN

Methicillin resistant Staphylococcus is an important worldwide problem. Resistance is verified in strains harboring the mecA gene and laboratory methods used to detect resistance are object of constant investigation. In the present study, 99 clinical isolates of staphylococci (41 S. aureus, 33 S. epidermidis, 12 S. saprophyticus and 13 members of other species) were submitted to different phenotypic methods and conditions. Detection of the mecA gene by PCR was used as the reference method and detected 14/41, 10/33, and 10/25 isolates of S. aureus, S. epidermidis and other species, respectively. Results showed that, for S. aureus and S. epidermidis, agar diffusion, agar dilution, and the E test incubated during 24h at 35 degrees C correctly discriminated mecA positive from mecA negative isolates. For other species, all methods and conditions presented low specificity (ranging from 20% to 66.7%) and, particularly S. saprophyticus, may need molecular methods to correctly assess methicillin resistance.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/análisis , Hexosiltransferasas , Inmunodifusión/métodos , Resistencia a la Meticilina , Pruebas de Sensibilidad Microbiana/métodos , Muramoilpentapéptido Carboxipeptidasa/análisis , Peptidil Transferasas , Staphylococcus/fisiología , Agar , Técnicas Bacteriológicas/métodos , Secuencia de Bases , Proteínas Portadoras/genética , Proteínas Portadoras/inmunología , Difusión , Genes Bacterianos/genética , Resistencia a la Meticilina/genética , Muramoilpentapéptido Carboxipeptidasa/genética , Muramoilpentapéptido Carboxipeptidasa/inmunología , Proteínas de Unión a las Penicilinas , Reacción en Cadena de la Polimerasa , Staphylococcus/enzimología , Staphylococcus/genética , Staphylococcus/inmunología

RESUMEN

Two hundred fifty-four methicillin-resistant Staphylococcus aureus (MRSA) strains typed by pulsed-field gel electrophoresis (PFGE) were tested by PCR for the mec-associated hypervariable region (HVR-PCR) to determine their number of direct repeat units (DRUs). Eight different groups of repeats were found among the MRSA strains and compared to 28 pulsotypes classified by PFGE. Some MRSA strains belonging to the same pulsotype showed different numbers of DRUs. HVR-PCR was rapid, easy to perform, and reproducible and has the ability to obtain an unambiguous positive result for each isolate analyzed. However, this technique shows a discriminatory power inferior to that of PFGE. We conclude that PFGE is a more reliable method of typing MRSA than HVR-PCR.

Asunto(s)

Proteínas Bacterianas , Técnicas de Tipificación Bacteriana , Proteínas Portadoras/genética , Hexosiltransferasas , Resistencia a la Meticilina , Muramoilpentapéptido Carboxipeptidasa/genética , Peptidil Transferasas , Polimorfismo Genético , Secuencias Repetitivas de Ácidos Nucleicos/genética , Staphylococcus aureus/clasificación , Electroforesis en Gel de Campo Pulsado , Humanos , Resistencia a la Meticilina/genética , Proteínas de Unión a las Penicilinas , Reacción en Cadena de la Polimerasa , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética

RESUMEN

The investigation of methicillin resistance in Staphylococcus aureus (MRSA) is a serious problem for the physician and microbiologist. Accurate and rapid detection is essential for the use of appropriate antimicrobial therapy and for the control of nosocomial spread of the resistant strain. The performance characteristics of the MicroScan Overnight Conventional Pos Combo 12 panels (MOCP), BBL Crystal MRSA ID (CR), E-test and agar screen plate (Muller Hinton agar with oxacillin 6 micrograms/ml and 4% NaCl) (AS) were evaluated for the detection of oxacillin resistance. Thirty S. aureus clinically significant strains with different PFGE (Pulse Field Gel Electrophoresis) banding pattern were tested, and 22 of them were mecA positive by PCR. These strains were also analyzed by mecA and Tn554 polymorphism. All mecA positive strains were classified as methicillin resistant by MOCP and E-test. CR and AS failed to detect oxacillin resistance in 2 strains. One false positive was only detected by E-test. Accurate testing for the presence of MRSA may reduce the need for empiric therapy with vancomycin for patients with staphylococcal infections. According to our results the best performance was obtained with MOCP. However, as a rapid method, CR gave acceptable sensitivity for clinical purposes.

Asunto(s)

Proteínas Bacterianas/análisis , Proteínas Portadoras/análisis , Hexosiltransferasas , Resistencia a la Meticilina , Pruebas de Sensibilidad Microbiana/métodos , Muramoilpentapéptido Carboxipeptidasa/análisis , Peptidil Transferasas , Staphylococcus aureus/efectos de los fármacos , Medios de Cultivo , Resistencia a Medicamentos/genética , Farmacorresistencia Bacteriana Múltiple/genética , Electroforesis en Gel de Campo Pulsado , Humanos , Resistencia a la Meticilina/genética , Oxacilina/farmacología , Proteínas de Unión a las Penicilinas , Reacción en Cadena de la Polimerasa , Juego de Reactivos para Diagnóstico , Sensibilidad y Especificidad , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Vancomicina/farmacología

RESUMEN

We describe the isolation and molecular characterization of methicillin-resistant coagulase-negative staphylococci (MRCNS) from the nasal flora of healthy humans from three institutions located in Rio de Janeiro City. Swabs were obtained from the nares of students attending a non-residential public school and adults from two military quarters. Isolates of staphylococci were tested for the presence of the mecA gene by hybridization with a specific probe. S. epidermidis was the most frequent MRCNS (38 of the total 45 CNS isolated). Twenty-five percent of nasal staphylococcal carriers studied were colonized with MRCNS. Pulsed-field gel electrophoresis (PFGE) of SmaI-digested genomic DNA was carried out to study the clonality of the methicillin-resistant S. epidermidis (MRSE) isolates. In addition to cross-colonization among individuals belonging to the same institution, familial cross-colonization appeared to contribute to the spread of the methicillin-resistant isolates among two inter-communicable institutions. Indeed, the wide genomic diversity among the MRSE flora suggests that the spread of the mecA gene among these isolates might also have occurred via horizontal transmission. Despite the limited number of institutions analysed, it is reasonable to conclude that our data do not represent a situation unique to the three organizations but may reflect other communities in Rio with respect to transmission of MRCNS.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/aislamiento & purificación , Variación Genética , Hexosiltransferasas , Resistencia a la Meticilina , Muramoilpentapéptido Carboxipeptidasa/aislamiento & purificación , Mucosa Nasal/microbiología , Peptidil Transferasas , Staphylococcus/efectos de los fármacos , Staphylococcus/aislamiento & purificación , Adolescente , Adulto , Brasil , Niño , Electroforesis en Gel de Campo Pulsado , Humanos , Persona de Mediana Edad , Proteínas de Unión a las Penicilinas , Staphylococcus/genética , Población Urbana

RESUMEN

In Colombia, penicillin resistance of Streptococcus pneumoniae invasive isolates recovered from children less than 5 years old has increased from 10% in 1994 to 49.4% in 1999, suggesting the circulation of international resistant clones in the country. A total of 167 S. pneumoniae invasive isolates with diminished susceptibility to penicillin (DSP) were studied. The techniques used were pulsed-field gel electrophoresis (PFGE) and restriction fragment length polymorphism (RFLP) of penicillin-binding proteins (PBPs) genes (2B, 2X, and 1A). Forty-nine serotype 23F isolates were grouped in two clusters: 15 (31%) multiresistant isolates showed PFGE pattern A and PBP I profile, thus making them indistinguishable from Spain23F-1 clone, and 34 (69%) with PFGE pattern C, PBP II profile, and intermediate level resistance (ILR) to penicillin and TMP-SMX, features unique to a Colombian clone. Fifty-five serotype 14 isolates were assigned to PFGE B pattern, PBP III profile, having high-level resistance to penicillin, and TMP-SMX, similar to the France9V variant 14. This same pattern was present in five capsular type 9V isolates. Four serotype 14 isolates were assigned to PFGE pattern F, and appeared to be similar to Slovakia(14)-10 PFGE pattern, although they had different PBP profiles. Nine capsular type 6B and one 6A isolates belonged to PFGE pattern M, similar to Spain6B-2, although they showed different PBP profiles. The remaining 44 isolates, corresponding to serotypes 14, 6B, 19F, and 34, showed variable PFGE and PBP patterns. These results show that as many as two international clones may be circulating in Colombia as well as a unique, widely distributed 23F clone with ILR to penicillin. Additionally, some Colombian isolates capsular type 14 and 6B might be related to Slovakia(14)-10 Spain6B-2 clones, respectively.

Asunto(s)

Proteínas Bacterianas , Hexosiltransferasas , Peptidil Transferasas , Infecciones Neumocócicas/microbiología , Streptococcus pneumoniae/efectos de los fármacos , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Colombia , Dermatoglifia del ADN , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Farmacorresistencia Microbiana , Electroforesis en Gel de Campo Pulsado , Humanos , Muramoilpentapéptido Carboxipeptidasa/genética , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Resistencia a las Penicilinas , Proteínas de Unión a las Penicilinas , Fenotipo , Serotipificación , Streptococcus pneumoniae/genética

RESUMEN

AIMS: To achieve reliable detection of methicillin resistance in clinical isolates of coagulase-negative staphylococci. METHODS AND RESULTS: Strains (105) were evaluated by normatized antimicrobial susceptibility methods, and for the presence of the methicillin resistance-determining mecA gene, using the polymerase chain reaction. Correlation between phenotypic and genotypic methods was obtained in 87.6% of the samples. Six strains, classified as methicillin-susceptible by phenotypic assays, revealed the presence of the mecA gene, indicating that methicillin resistance expression was probably repressed. Another seven isolates failed to show mecA amplification after displaying methicillin resistance in phenotypic evaluations. The susceptibility of the methicillin-resistant isolates to other antimicrobial agents was variable. CONCLUSION: Genotypic determination of the mecA gene proved to be the most reliable method for detection of methicillin resistance. SIGNIFICANCE AND IMPACT OF THE STUDY: Correct assessment of methicillin resistance, such as that attained through genotyping, is essential for defining therapeutic strategies, particularly when treating severely compromised patients.

Asunto(s)

Proteínas Bacterianas , Coagulasa/metabolismo , Hexosiltransferasas , Resistencia a la Meticilina/genética , Meticilina/farmacología , Peptidil Transferasas , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Proteínas Portadoras/genética , Genes Bacterianos/genética , Genotipo , Meticilina/uso terapéutico , Pruebas de Sensibilidad Microbiana , Muramoilpentapéptido Carboxipeptidasa/genética , Proteínas de Unión a las Penicilinas , Fenotipo , Reacción en Cadena de la Polimerasa , Staphylococcus/clasificación , Staphylococcus/enzimología

RESUMEN

All detectable high-molecular-mass penicillin-binding proteins (HMM PBPs) are altered in a clinical isolate of Streptococcus mitis for which the beta-lactam MICs are increased from those previously reported in our region (cefotaxime MIC, 64 microg/ml). These proteins were hardly detected at concentrations that saturate all PBPs in clinical isolates and showed, after densitometric analysis, 50-fold-lower radiotracer binding. Resistance was related to mosaic structure in all HMM PBP-coding genes, where critical region replacement was complemented not only by substitutions already reported for the closely related Streptococcus pneumoniae but also by other specific replacements that are presumably close to the active-site serine. Mosaic structure was also presumed in a pbp1a-sensitive strain used for comparison, confirming that these structures do not unambiguously imply, by themselves, detectable critical changes in the kinetic properties of these proteins.

Asunto(s)

Proteínas Portadoras/metabolismo , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Streptococcus/metabolismo , Resistencia betalactámica/fisiología , Sustitución de Aminoácidos , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Proteínas Portadoras/genética , ADN Bacteriano/análisis , Amplificación de Genes , Hexosiltransferasas/genética , Hexosiltransferasas/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana , Peso Molecular , Complejos Multienzimáticos/genética , Complejos Multienzimáticos/metabolismo , Muramoilpentapéptido Carboxipeptidasa/genética , Proteínas de Unión a las Penicilinas , Peptidil Transferasas/genética , Peptidil Transferasas/metabolismo , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Streptococcus/efectos de los fármacos , Streptococcus/genética , Superóxido Dismutasa/genética , beta-Lactamas

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) is recognised as an important cause of nosocomial infection. The spread of some MRSA epidemic clones is well documented. In Brazil, and more recently in Portugal, a considerable number of hospital infections has been caused by a unique multiresistant MRSA clone designated as the Brazilian epidemic clone. This paper describes the spread of this clone in hospitals in two cities in Argentina.

Asunto(s)

Proteínas Portadoras/genética , Infección Hospitalaria/epidemiología , Hexosiltransferasas , Resistencia a la Meticilina , Muramoilpentapéptido Carboxipeptidasa/genética , Peptidil Transferasas , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/farmacología , Argentina/epidemiología , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Brasil/epidemiología , Infección Hospitalaria/microbiología , Infección Hospitalaria/transmisión , Elementos Transponibles de ADN , Brotes de Enfermedades , Electroforesis en Gel de Campo Pulsado , Hospitales Urbanos , Humanos , Pruebas de Sensibilidad Microbiana , Proteínas de Unión a las Penicilinas , Polimorfismo Genético , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/transmisión , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación

RESUMEN

The penicillin-binding proteins of 11 pathogenic Escherichia coli strains, including enteropathogenic, enterotoxigenic, enteroinvasive, enteroaggregative, and enterohemorrhagic E. coli, were detected in gels following the labeling of isolated cell envelopes with [3H]benzylpenicillin. The electrophoretic profiles, sensitivities to and morphological changes induced by beta-lactam antibiotics showed that the penicillin-binding proteins of most pathogenic E. coli possess structural and physiological functions similar to those of E. coli K12.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/química , Proteínas Portadoras/metabolismo , Diarrea/microbiología , Infecciones por Escherichia coli/microbiología , Escherichia coli/química , Hexosiltransferasas , Muramoilpentapéptido Carboxipeptidasa/química , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Peptidil Transferasas , Antibacterianos/metabolismo , Antibacterianos/farmacología , Proteínas Portadoras/aislamiento & purificación , Electroforesis en Gel de Poliacrilamida , Escherichia coli/clasificación , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Humanos , Lactamas , Pruebas de Sensibilidad Microbiana , Muramoilpentapéptido Carboxipeptidasa/aislamiento & purificación , Proteínas de Unión a las Penicilinas , Serotipificación

RESUMEN

The affinities of six major penicillin-binding proteins (PBPs) of Yersinia pestis EV76 to different beta-lactam antibiotics were determined. The results indicate that, similar to their counterparts in Escherichia coli, PBP2 and PBP3 are the lethal targets of amdinocillin and furazlocillin, respectively. The PBP contents of four additional Y. pestis strains and the morphological effects produced by some beta-lactam antibiotics are also reported.

Asunto(s)

Antibacterianos/metabolismo , Proteínas Bacterianas , Proteínas Portadoras/metabolismo , Hexosiltransferasas , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Peptidil Transferasas , Yersinia pestis/metabolismo , Antibacterianos/farmacología , Proteínas Portadoras/química , Muramoilpentapéptido Carboxipeptidasa/química , Proteínas de Unión a las Penicilinas , Unión Proteica , Yersinia pestis/efectos de los fármacos , Yersinia pestis/ultraestructura , beta-Lactamas

RESUMEN

Six major bands corresponding to penicillin-binding proteins (PBPs) with molecular weights ranging from 43,000 to 97,000 were detected in cell envelopes of Yersinia pestis EV76 grown at 28 degrees C. When cells were transferred to 37 degrees C and incubated for extended periods of time, the amounts of all PBPs, except for PBP2, were gradually reduced in cell envelopes of a strain carrying a 75-kb virulence-associated plasmid (as measured by penicillin-binding capacity), whereas in a strain cured of the plasmid, all PBPs were stable. The results indicated that the stability and/or the expression of Y. pestis PBPs is affected by a temperature-inducible pathway associated with the virulence-associated plasmid.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/análisis , Hexosiltransferasas , Muramoilpentapéptido Carboxipeptidasa/análisis , Penicilinas/metabolismo , Peptidil Transferasas , Plásmidos , Yersinia pestis/química , Proteínas de Unión a las Penicilinas , Temperatura , Yersinia pestis/genética

RESUMEN

The extensive use of antibiotics in Nicaragua raises concerns about the resulting levels of susceptibility of pathogenic bacteria. This is the first study that characterizes 18 strains of N. gonorrhoeae isolated in Nicaragua (1989), for their antibiotic susceptibility. Strains were predominantly of the auxotype/serotype Proto/PIB. There was no difference in lipopolysaccharides profiles obtained after SDS-PAGE for all strains. Variable expression of the PII outer membrane protein was not associated to antimicrobial resistance. All strains were susceptible to ceftriaxone, spectinomycin, rifampin and cefoxitin. The strains were classified in five groups based on plasmid profiles. A total of 78% of the isolates were penicillinase-producing (PPNG) and 22% were tetracycline-resistant N. gonorrhoeae (TRNG). One PPNG strain showed a concomitant decreased of penicillin binding to penicillin-binding protein 2. These randomly chosen isolates of N. gonorrhoeae from Nicaragua possess high levels of resistance to multiple families of drugs.

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PIP: In Nicaragua, in 1989, health workers obtained urethral or cervical samples from 18 people with gonorrhea attending public health clinics in Managua and sent them to the National Laboratory of Public Health in Managua for characterization of their antibiotic susceptibility. Of the 18 strains, 15 (83.3%) were of the auxotype/serotype Proto/PIB. Electrophoresis of lipopolysaccharides on SDS-polyacrylamide gels (15%) with 4 M urea revealed no difference in lipopolysaccharide profiles for all strains. The variable expression of the 31-kDa opacity outer membrane protein was not related to antimicrobial resistance. All isolates exhibited susceptibility to ceftriaxone, spectinomycin, cefazolin, cefoxitin, and rifampin. 78% of the strains produced beta-lactamase. 89% of the strains were resistant to penicillin and ampicillin, 44% were resistant to tetracycline, 28% were resistant to cefamandol, 22% were resistant to chloramphenicol, and 11% were resistant to erythromycin. There were 5 distinct groups of Neisseria gonorrhoeae isolated according to their plasmid profiles. The largest was plasmid profile group 1 (55.6%), defined as carrying the 24.5, 3.2, and 2.6 MDa plasmids. It produced beta-lactamase. Penicillinase-producing N. gonorrhoeae (PPNG) comprised 78% of the isolates, 22% of whom were tetracycline-resistant N. gonorrhoea. One PPNG strain exhibited a parallel decrease of penicillin binding to penicillin-binding protein 2. These findings confirmed the presence of multiresistant N. gonorrhoeae strains in Managua, Nicaragua. Based on these findings, the researchers recommended that penicillin and tetracycline not be used to treat gonorrhea in Nicaragua; they recommended ceftriaxone and spectinomycin.

Asunto(s)

Proteínas Bacterianas , Farmacorresistencia Microbiana , Hexosiltransferasas , Neisseria gonorrhoeae/efectos de los fármacos , Peptidil Transferasas , Proteínas de la Membrana Bacteriana Externa/análisis , Proteínas de la Membrana Bacteriana Externa/aislamiento & purificación , Proteínas Portadoras/análisis , ADN Bacteriano/análisis , ADN Bacteriano/aislamiento & purificación , Farmacorresistencia Microbiana/genética , Electroforesis en Gel de Poliacrilamida , Humanos , Lipopolisacáridos/análisis , Lipopolisacáridos/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Muramoilpentapéptido Carboxipeptidasa/análisis , Neisseria gonorrhoeae/clasificación , Neisseria gonorrhoeae/genética , Neisseria gonorrhoeae/metabolismo , Nicaragua , Resistencia a las Penicilinas/genética , Proteínas de Unión a las Penicilinas , Penicilinas/metabolismo , Factores R , Resistencia a la Tetraciclina/genética

RESUMEN

Purified membranes of Listeria monocytogenes ATCC 15313 contain at least five penicillin-binding proteins. In two dicloxacillin-resistant mutants, derived from a sensitive parent strain, a 16-fold increase in the MIC of dicloxacillin was observed. A less-significant increase was detected in the MICs of other beta-lactam drugs. In the mutants, PBP 3 lost its strong affinity for dicloxacillin, but remained fully susceptible to binding of 125I-penicillin X, as compared with the wild-type strain. PBP 2 could not be detected in one of the mutants. No decrease in affinity for the radioactive tracer or dicloxacillin was detected in any other PBP of the resistant mutants.

Asunto(s)

Aciltransferasas/metabolismo , Proteínas Bacterianas , Proteínas Portadoras/metabolismo , Dicloxacilina/farmacología , Hexosiltransferasas/metabolismo , Listeria monocytogenes/genética , Complejos Multienzimáticos/metabolismo , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Resistencia a las Penicilinas/genética , Peptidil Transferasas/metabolismo , Membrana Celular/metabolismo , Radioisótopos de Yodo , Listeria monocytogenes/metabolismo , Pruebas de Sensibilidad Microbiana , Mutación , Proteínas de Unión a las Penicilinas

RESUMEN

The Penicillin-Binding Proteins (PBP) of Listeria monocytogenes 29-CCM-A: 454 (ATCC 15313) are described by the use of 125I-Penicillin X as radiotracer. The membranes of this tolerant bacilli contained at least five proteins with different affinities for the radiotracer or Dicloxacillin. The molecular weights of these proteins were estimated as 76, 74, 67, 66 and 47 KDa. Dicloxacillin induced the formation of straight filaments when present at sub-inhibitory concentrations, while Penicillin G did not induce any visible alteration in the morphology of this microorganism.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/análisis , Hexosiltransferasas , Listeria monocytogenes/análisis , Muramoilpentapéptido Carboxipeptidasa/análisis , Peptidil Transferasas , Dicloxacilina/farmacología , Listeria monocytogenes/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Proteínas de Unión a las Penicilinas

RESUMEN

Antibacterial potency of cephalosporins depends on inhibition (acylation) of one or more penicillin-binding proteins (PBP). Recently, reduced affinity of PBP for cephalosporins and other B-lactam agents has been found in some cases. Mechanism for these changes in affinity are analyzed in this review.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/metabolismo , Cefalosporinas/metabolismo , Hexosiltransferasas , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Peptidil Transferasas , Acetilación , Farmacorresistencia Microbiana , Bacterias Gramnegativas/metabolismo , Bacterias Grampositivas/metabolismo , Proteínas de Unión a las Penicilinas

RESUMEN

We questioned if PBP analysis could differentiate strains of Haemophilus influenzae, H. aegyptius, and H. influenzae biogroup aegyptius associated with Brazilian Purpuric Fever. A relatively homogeneous PBP pattern was observed for all strains. The amount of penicillin bound to PBP 5 appeared to separate H. influenzae and H. aegyptius isolates, whereas PBP 5 of those strains associated with Brazilian Purpuric Fever bound an intermediate amount. We conclude that based on PBP profiles, the strains tested appear to be difficult to separate taxonomically and may represent a common species.

Asunto(s)

Proteínas Bacterianas , Proteínas Portadoras/análisis , Infecciones por Haemophilus/microbiología , Haemophilus influenzae/clasificación , Haemophilus/clasificación , Hexosiltransferasas , Muramoilpentapéptido Carboxipeptidasa/análisis , Peptidil Transferasas , Púrpura/microbiología , Densitometría , Haemophilus/metabolismo , Haemophilus influenzae/metabolismo , Humanos , Proteínas de Unión a las Penicilinas , Penicilinas/metabolismo

Asunto(s)

Muramoilpentapéptido Carboxipeptidasa/metabolismo , Cefalosporinas/farmacología , Acetilación , Farmacorresistencia Microbiana , Cefalosporinas/metabolismo , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos