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L M Teixeira

Publications and source records attributed to L M Teixeira.

At least 19 recordsLinked to original sources
PubMed2006

Genetic relatedness of a non-motile variant O157 enteropathogenic Escherichia coli (EPEC) strain and E. coli strains belonging to pathogenic related groups.

The study was undertaken to determine the clonal relationship and the genetic diversity among Escherichia coli isolates by comparing a non-motile O157 variant with three O157:H7 EHEC isolates and one O55:H7 enteropathogenic E. coli (EPEC) strain. E. coli strains were characterized by sorbitol phenotype, multilocus enzyme electrophoresis, pulsed-field gel electrophoresis, random amplification polymorphic DNA, and the presence of specific virulence genes (stx, E-hly and LEE genes). Sorbitol fermentation was observed in O157:H- (strain 116I), O55:H7 and O157:H7 (strain GC148) serotypes. stx1 or stx2 and E-hly genes were only detected among O157:H7 isolates. LEE typing revealed specific allele distribution: eaegamma, tirgamma, espAgamma, espBgamma associated with EPEC O55:H7 and EHEC O157:H7 strains (B1/1 and EDL 933), eaealpha, tiralpha, espAalpha, espBalpha related to the 116I O157:H- strain and the GC148 strain presented non-typable LEE sequences. Multilocus enzyme profiles revealed two main clusters associated with specific LEE pathotypes. E. coli strains were discriminated by random amplification of polymorphic DNA-polymerase chain reaction and pulsed-field gel electrophoresis methodologies. The molecular approaches used in this study allowed the determination of the genetic relatedness among E. coli strains as well as the detection of lineage specific group markers.

Animals↗
PubMed2005

Detection of a chloramphenicol efflux system in Escherichia coli isolated from poultry carcass.

An active chloramphenicol efflux system was demonstrated in a multiresistant E. coli isolated from poultry carcass. The effect of different concentrations of chloramphenicol on the original strain and on the plasmid-cured strain was determined in the presence and in the absence of CCCP, an uncoupler of the proton-motive force. Minimal inhibitory concentration (MIC) was lower in the presence of CCCP in the original strain. The plasmid-cured strain displayed lower resistance for chloramphenicol than the wild type, but the MIC was not affected by CCCP. The combined results indicate a plasmid encoded energy dependent resistance mechanism. 3H-chloramphenicol accumulation within the cells was measured by scintillation counting. The uptake or the efflux of 3H-chloramphenicol was influenced by CCCP in the original strain, but not in the plasmid-cured strain. More than one chloramphenicol resistance mechanism may exist in this strain. E. coli is an important commensal or pathogen that inhabits the gastrointestinal tracts of humans and animals, so a plasmid encoded active drug resistance mechanism can be a potential source of horizontal transfer of resistance.

Animals↗
PubMed2005

Genomic characterization of oxacillin-resistant Staphylococcus epidermidis and Staphylococcus haemolyticus isolated from Brazilian medical centres.

Studies on the genetic diversity of oxacillin-resistant coagulase-negative staphylococcal (CNS) isolates are important for the control and prevention of infections. The present study evaluated the clonal diversity of oxacillin-resistant Staphylococcus epidermidis (ORSE) and Staphylococcus haemolyticus (ORSH) strains, isolated from patients in nine Brazilian medical centres by using pulsed-field gel electrophoresis (PFGE) after digestion of bacterial DNA using SmaI. PFGE analysis of ORSE (N=44) and ORSH (N=25) strains showed the presence of 29 restriction profiles clustered in 16 PFGE types, and 21 distinct profiles in 15 PFGE types, respectively, indicating a large genetic diversity among isolates of both of these species. Among the ORSE isolates, 23 (52%) strains belonged to two predominant PFGE types (named A and B), which were observed in most of the hospitals assessed, indicating the spread of these PFGE types in hospitals located in Rio de Janeiro. The spread of PFGE types of ORSH was also detected in some of the hospitals investigated. The results show that PFGE is a suitable tool for epidemiological studies of oxacillin-resistant CNS, and can be used as a basis for infection control procedures for these multiresistant organisms.

Bacterial Proteins↗
PubMed2005

Ralstonia pickettii and Burkholderia cepacia complex bloodstream infections related to infusion of contaminated water for injection.

Ralstonia pickettii and Burkholderia cepacia complex isolates are causes of healthcare-associated infection related to contamination of intravenously administered products. Based on microbiological and epidemiological data and molecular typing by pulsed-field gel electrophoresis, we report the occurrence of two outbreaks of R. pickettii and B. cepacia complex bloodstream infections. The first outbreak occurred from August 1995 to September 1996, and the second outbreak occurred from 28 March to 8 April 1998, affecting adults and neonates, respectively. Infusion of contaminated water for injection was the source of infection.

Adult↗
PubMed2005

Characterization of Staphylococcus aureus isolates recovered from bovine mastitis in Rio de Janeiro, Brazil.

Phenotypic characteristics, antimicrobial susceptibility, and genetic relationships were analyzed in 107 Staphylococcus aureus isolates recovered from cows with subclinical mastitis in Southeastern Brazil. Thirteen different biochemical patterns were detected among isolates. A predominant pattern represented by about 54% of the isolates was distributed among several herds. Isolates of distinct phenotypic profiles were also detected within a herd. Susceptibility to ampicillin, cefotaxime, cephalotin, chloramphenicol, erythromycin, gentamycin, kanamycin, nitrofurantoin, norfloxacin, ofloxacin, oxacillin, penicillin, rifampin, sulfamethoxazole-trimethoprim, tetracycline, trimethoprim, and vancomycin, determined by the disk diffusion method, was observed in 44.9% of isolates. On the other hand, 55.1, 7.4, and 2.8% of the strains were resistant to ampicillin/penicillin, tetracycline, and erythromycin, respectively. Genetic diversity was analyzed by pulsed-field gel electrophoresis using SmaI as the restriction enzyme. All isolates could be typed by pulsed-field gel electrophoresis, which identified 16 types and 24 subtypes. Type A and its subtypes comprised 54.2% of all isolates and were recovered from 6 of the 9 herds analyzed. Other types and subtypes were also found in multiple herds. Although multiple types and subtypes were found within a specific herd, a predominant type was frequently observed.

Animals↗
PubMed2004

Frequency and characteristics of diarrhoeagenic Escherichia coli strains isolated from children with and without diarrhoea in Rio de Janeiro, Brazil.

The frequency of diarrhoeagenic Escherichia coli (DEC) strains was investigated in 253 children up to 3 years old, with (patient group, PG, 199 children) and without (control group, CG, 54 children) diarrhoea, living in Rio de Janeiro, Brazil. DEC strains were detected in 70 (27.6%) children, including 54 (27.1%) with diarrhoea and 16 (29.6%) without diarrhoea. Enteroaggregative E. coli (EAEC) was the most frequent DEC category, accounting for 14.6% of the isolates in the PG and for 11.1% in the CG. E. coli strains carrying enteropathogenic E. coli (EPEC) virulence markers showed higher incidence in the CG (12.9%) than in the PG (8.0%). E. coli strains belonging to non-classical EPEC groups that carried eae only or eae and bfpA, designated as attaching-effacing E. coli (AEEC) were the most frequent (79.1%). Simultaneous presence of multiple EPEC virulence factors (EAF/eae/bfpA) were only detected among strains isolated from the PG. Enterotoxigenic E. coli (ETEC) strains were isolated from 5.5% of the children in the CG and from 3.5% of those in the PG. Most of the ETEC isolates were LT-probe positive (70%) and none carried both LT-I and ST-I probe sequences. One enteroinvasive E. coli (EIEC) strain was recovered from a child with diarrhoea. No stx-probe positive E. coli strains were detected. Overall, DEC strains were not found to be significantly associated with diarrhoea (p>0.05). However, the higher incidence of EAEC, the most frequent DEC category, among children with diarrhoea, suggests a potential role of EAEC as an important enteric pathogen in the community investigated.

Agglutination Tests↗
PubMed2003

Factors associated with penicillin-nonsusceptible pneumococcal infections in Brazil.

Resistance of Streptococcus pneumoniae is a worldwide, growing problem. Studies of factors associated with resistance to penicillin have not been conducted in Brazil. The objective of the present study was to evaluate factors associated with infection by S. pneumoniae not susceptible to penicillin. A prevalence study was conducted including all patients with a positive culture for S. pneumoniae in a hospital from July 1991 to December 1992 and the year 1994. Of 165 patients identified, 139 were considered to have clinically relevant infections and 88% of them had invasive infections. All infections were community acquired and consisted of pneumonia (44%) and of central nervous system (19%), pelvic or abdominal (12%), upper airway or ocular (12%), primary bloodstream (9%) and skin and soft tissue (5%) infections. Mortality was 25%. Susceptibility to penicillin was present in 77.6% of the isolates; 21.8% were relatively resistant, and one isolate was resistant (minimal inhibitory concentration = 4 micro g/ml). Multivariate analysis showed that age below 4 years (odds ratio (OR): 3.53, 95% confidence interval (95%CI): 1.39-8.96) and renal failure (OR: 5.50, 95%CI: 1.07-28.36) were associated with lack of susceptibility to penicillin. Bacteremia occurred significantly less frequently in penicillin-nonsusceptible infections (OR: 0.34, 95%CI: 0.14-0.84), possibly suggesting that lack of penicillin susceptibility is associated with lower virulence in S. pneumoniae.

Adolescent↗
PubMed2003

Antimicrobial susceptibility and survey of macrolide resistance mechanisms among Streptococcus pyogenes isolated in Rio de Janeiro, Brazil.

A total of 357 clinical Streptococcus pyogenes isolates collected between 1994 and 1999 in Rio de Janeiro city were tested for susceptibility to 10 antimicrobial drugs by agar-diffusion tests. All isolates were susceptible to penicillin, cephems, and vancomycin. High resistance rates were observed for tetracycline (43.1%) and trimethoprim/sulfamethoxazole (77.9%). Three isolates (0.8%) were resistant to erythromycin, and three exhibited intermediate susceptibility. Determination of the erythromycin MICs by the agar dilution method, showed 1.6% of erythromycin resistant isolates (the three erythromycin-resistant and the three erythromycin-intermediate isolates found by agar-diffusion test). Of the erythromycin-resistant isolates subjected to the double-disc diffusion test for erythromycin and clindamycin, three isolates expressed the iMLSB and three the M phenotype. The resistance phenotypes were confirmed by comparing the clindamycin MICs determined under normal testing conditions and those determined after induction by pre-growth in 0.06 microg/ml of erythromycin. Three ermTR and three mefA-containing isolates were detected by PCR. In strains belonging to the iMLSB phenotype, two clones were identified by PFGE following restriction with SmaI. M phenotype isolates could not be restricted with SmaI. Our results indicate a low rate of erythromycin resistance among S. pyogenes isolated in Rio de Janeiro, Brazil, and pointed to the presence of both resistance mechanisms found in streptococci.

Anti-Bacterial Agents↗
PubMed2001

Evaluation of an automated system for the identification and antimicrobial susceptibility testing of enterococci.

The performance of a new version of an automated system panel, the Positive Combo Panel Type 11 of MicroScan WalkAway 96 (WA96; Dade Behring) was evaluated and compared to that of reference methods for the identification and for antimicrobial susceptibility testing of the different enterococcal species. A total of 376 enterococcal isolates were tested. The MicroScan WA96 correctly identified 99.6% (266/267), 78.3% (18/23) and 68.6% (59/86) of Enterococcus faecalis, Enterococcus faecium and species other than E. faecalis and E. faecium, respectively. Although low probability of accurate identification was obtained for 37 (9.8%) strains, the system indicated that supplementary tests were necessary for precise identification of 8 (9.3%) among the 86 strains included in the non-faecalis/non-faecium group and of 3 (13.0%) among the E. faecium isolates. In comparison to the agar screening method, the percentage of agreement for detection of resistance markers by the automated system was 90.2% (37/41) for ampicillin, 90.6% (48/53) for high-level resistance to streptomycin (HLRS), 96.4% (80/83) for high-level resistance to gentamicin (HLRG), and 100% (14/14) for vancomycin. The results indicate that the MicroScan WA96 performed well for the identification of E. faecalis and typical E. faecium isolates, and for the detection of resistance to vancomycin and HLRG. However, the system still needs further improvement in order to provide reliable results for the characterization of the other enterococcal species, including atypical variants of E. faecium.

Autoanalysis↗
PubMed2001

Typing of Staphylococcus aureus from surgical site infections: comparison of pulsed-field gel electrophoresis (PFGE) and PCR technique using repetitive extragenic palindromic (rep) and Tn916-Shine-Dalgarno (TnSD) target sequences.

Staphylococcus aureus continues to be the main cause of surgical site infections. DNA typing is useful for studying this type of infection and establishing control programs within hospitals. In this study 19 S. aureus strains were isolated from surgical site infections of 19 patients, between August and December 1994 at the Rio de Janeiro University Hospital. The strains were typed by pulsed-field gel electrophoresis (PFGE) and by two polymerase chain reaction techniques targeting the repetitive extragenic palindromic and Tn916-Shine Dalgarno sequences. Analysis of the PFGE patterns divided the collection into 15 types, while PCR techniques identified 11 distinct strain patterns. There were two clusters, 1 of four strains and 1 of two strains with related PFGE and PCR patterns. Of the remaining strains, 10 were clustered in 5 PCR patterns but their PFGE patterns showed 4 to 6 different bands, and they were considered to be possibly related. The comparison of the S. aureus typing systems in the present study indicated that the PCR methods are useful for initial screening of genetically related isolates, but strains with identical PCR fingerprint need to be typed with PFGE for detailed strain differentiation.

Bacterial Typing Techniques↗
PubMed2001

Enterococcus porcinus sp. nov. and Enterococcus ratti sp. nov., associated with enteric disorders in animals.

Recent insights have been brought to the taxonomy of the genus Enterococcus by studies applying whole-cell protein analysis and DNA-DNA reassociation experiments, in addition to conventional physiological tests. Using these techniques, a group of 10 strains resembling the physiological group III of enterococcal species was characterized. Five strains were recovered from pigs and five from rats with enteric disorders. On the basis of the results of conventional physiological tests, the most likely identity of these strains was Enterococcus durans or Enterococcus hirae. Analysis of the electrophoretic whole-cell protein profiles showed two distinct clusters of virtually indistinguishable profiles: one composed of strains isolated from pigs, and one composed of strains isolated from rats. These protein profiles were not similar to the profiles of any previously described Enterococcus species. The results of DNA-DNA relatedness experiments were consistent with the results of the protein-profile analysis. The high levels of DNA relatedness found for pig isolates demonstrated that they belong to a new enterococcal species, for which the designation Enterococcus porcinus sp. nov. is proposed (type strain =DS 1390-83T =ATCC 700913T =CCUG 43229T =NCIMB 13634T). Strains isolated from rats were found to comprise another new species, for which the designation Enterococcus ratti sp. nov. is proposed (type strain =DS 2705-87T =ATCC 700914T =CCUG 43228T =NCIMB 13635T). This report provides data on the phenotypic and genotypic characterization of these two new enterococcal species, which may represent diarrhoeagenic pathogens for animals.

Animals↗
PubMed2001

Phenotypic and genotypic characterization of Pediococcus strains isolated from human clinical sources.

Seventy-two strains of pediococci isolated from human clinical sources were characterized by conventional physiological tests, chromogenic enzymatic tests, analysis of whole-cell protein profiles (WCPP) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and analysis of chromosomal DNA restriction profiles by pulsed-field gel electrophoresis (PFGE). Conventional tests allowed identification of 67 isolates: 52 strains were identified as Pediococcus acidilactici, 15 strains were identified as Pediococcus pentosaceus, and 5 strains were not identified because of atypical reactions. Analysis of WCPP identified all isolates since each species had a unique WCPP. By the WCPP method, the atypical strains were identified as P. acidilactici (two strains) and P. pentosaceus (three strains). The chromogenic substrate test with o-nitrophenyl-beta-D-glucopyranoside differentiated all 54 strains of P. acidilactici (negative reactions) and 13 (72%) of 18 strains of P. pentosaceus (positive reactions). Isolates of both species were shown to be nonclonal as revealed by the genetic diversity when chromosomal DNA was analyzed by PFGE. Using WCPP as the definitive identification procedure, P. acidilactici (28 of 54 strains; 51.8%) was more likely than P. pentosaceus (4 of 18 strains; 22.3%) to be isolated from blood cultures.

Bacterial Typing Techniques↗
PubMed2001

Genetic and phenotypic features of Streptococcus pyogenes strains isolated in Brazil that harbor new emm sequences.

In the present study, 37 group A Streptococcus (GAS) strains belonging to 13 new emm sequence types identified among GAS strains randomly isolated in Brazil were characterized by using phenotypic and genotypic methods. The new types were designated st204, st211, st213, st809, st833, st854, st2904, st2911, st2917, st2926, st3757, st3765, and st6735. All isolates were susceptible to the antimicrobial agents tested, except to tetracycline. They all carried the speB gene, and 94.6% produced detectable SpeB. Most strains belonging to a given emm type had similar or highly related pulsed-field gel electrophoresis profiles that were distinct from profiles of strains of another type. The other characteristics were variable from isolate to isolate, although some associations were consistently found within some emm types. Unlike the other isolates, all type st213 isolates were speA positive and produced SpeA. Strains belonging to st3765 were T6 and opacity factor (OF) negative. Individual isolates within OF-positive emm types were associated with unique sof gene sequence types, while OF-negative isolates were sof negative by PCR. This report provides information on new emm sequence types first detected in GAS isolates from a geographic area not extensively surveyed. Such data can contribute to a better understanding of the local and global dynamics of GAS populations and of the epidemiological aspects of GAS infections occurring in tropical regions.

Antigens, Bacterial↗
PubMed2000

Epidemic nephritis in Nova Serrana, Brazil.

BACKGROUND: Outbreaks of nephritis have been rare since the 1970s. From December, 1997, to July, 1998, 253 cases of acute nephritis were identified in Nova Serrana, Brazil. Seven patients required dialysis, and three patients died. We did a case-control study to investigate the cause of the outbreak. METHODS: Using a matched cluster design, we examined seven recent patients, their family members (n=23), and members of neighbourhood-matched control households (n=22). We subsequently interviewed 50 patients and 50 matched controls about exposure to various dairy products. We also cultured dairy foods and took udder-swab and milk samples from cows. FINDINGS: Throat cultures indicated that nephritis was associated with group C Streptococcus equi subspecies zooepidemicus, a cause of bovine mastitis. S. zooepidemicus was detected in four of seven case households (six of 30 people) and no control households (p=0.09). Patients were more likely than matched controls to have consumed a locally produced cheese called queijo fresco (matched odds ratio 2.1, p=0.05). The nephritis attack rate was 4.5 per 1000 in Nova Serrana but 18 per 1000 in the village Quilombo do Gaia (p=0.003). The largest supplier of unpasteurized queijo fresco was a farm in Quilombo do Gaia. S. zooepidemicus was not detected in food samples or in swabs collected from cows in August, 1998, although mastitis was evident among cows on the suspected farm. Throat cultures of the two women who prepared cheese on this farm yielded the outbreak strain of S. zooepidemicus. After the cheese was removed from the distribution system, no further cases were reported. INTERPRETATION: A large outbreak of glomerulonephritis was attributed to S. zooepidemicus in unpasteurised cheese. This outbreak highlights the dangers of consuming unpasteurized dairy products and need for global efforts to promote food safety.

Adolescent↗
PubMed2000

Antimicrobial susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis collected from five centers in Brazil, 1997-98.

OBJECTIVE: To assess the susceptibility of the key respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis to antimicrobial agents used to treat respiratory tract infections. METHODS: Isolates were collected from five centers in Brazil during 1997-98, and susceptibility testing was conducted at a central laboratory according to National Committee for Clinical Laboratory Standards criteria. RESULTS: Of the 359Streptococcus pneumoniae isolates tested, 77% were susceptible, 19% were intermediate and 4% were resistant to penicillin. The susceptibility of S. pneumoniae to other beta-lactams and macrolides was greater than 90%, but cotrimoxazole was active against only 48% of the isolates. The prevalence of susceptible isolates was 100.0% for vancomycin and 99.7% for levofloxacin. beta-Lactam, macrolide, and cotrimoxazole activities were negatively associated with penicillin resistance. Of the 219 isolates of Haemophilus influenzae tested, 11% produced beta-lactamase and 11% were not susceptible to ampicillin. Nearly all H. influenzae isolates were susceptible to all other drugs, except cotrimoxazole (47% susceptibility). Of the 52 Moraxella catarrhalis isolates, 98% produced beta-lactamase, and the MIC of all drugs was </=4 mg/L, with the exception of ampicillin, where the MIC90 was> 8 mg/L. CONCLUSIONS: When these data are compared with previous reports, our findings suggest that the prevalence of pneumococci that are resistant to agents such as penicillin and cotrimoxazole may be increasing in Brazil, which highlights the need to continue surveillance programs.

Anti-Bacterial Agents↗
PubMed1999

Characterization of a novel bacteriocin-encoding plasmid found in clinical isolates of Staphylococcus aureus.

Plasmids specifying bacteriocin production and immunity to its action were found in three clinical isolates of Staphylococcus aureus obtained in different hospitals located in Rio de Janeiro. These plasmids (pRJ28, pRJ29 and pRJ30) of 8.0 kb were found to generate identical restriction fragment patterns upon digestion with several enzymes, although the range of strains susceptible to the respective bacteriocin varied among the producer strains, when different Gram-positive bacteria were used as indicators, pRJ29 was then chosen for further characterization in order to compare it with pRJ6 and pRJ9, two small bacteriocin-encoding plasmids previously described in strains isolated from food. pRJ29 was found to code for a bacteriocin with chemical properties (sensitivity to proteases, heat resistance, activity under anaerobiosis, and estimated molecular weight) similar to those of pRJ6-encoded bacteriocin, conferring cross-immunity to it. However, its restriction map differed from those of pRJ6 and pRJ9. These studies together with hybridization, incompatibility, and mobilization analyses using a derivative of pRJ29 tagged with Tn917-lac suggest that pRJ29 is a mosaic composed of genetic determinants found on pRJ6 and pRJ9, and that IS257 was not involved in the recombination events which gave rise to pRJ29.

Bacteriocins↗