Epidermal growth factor vs platelet-rich plasma: Activity against chronic wound microbiota.

The objective was to evaluate Staphylococcus aureus and Pseudomonas aeruginosa colonisation of wounds treated with recombinant epidermal growth factor (EGF) and platelet-rich plasma (PRP); to analyse the susceptibility profiles of S. aureus and P. aeruginosa isolates from wounds treated with EGF and PRP; and to describe the presence of infection in EGF-treated and PRP-treated wounds. Experimental study was performed using clinical specimens collected with swabs. Patients were treated with PRP and EGF in the outpatient clinic of a university hospital. Forty-three isolates were obtained from 31 patients, 41.9% (13/31) of whom had been treated with EGF and 58.0% (18/31) with PRP. Ten of the 43 isolates were identified as S. aureus, 60.0% (6/10) of which were isolated from PRP-treated wounds. Among the 33 P. aeruginosa isolates, 66.6% (22/33) were isolated from PRP-treated wounds. Regarding antimicrobial susceptibility, only one strain isolated from an EGF-treated wound was identified as methicillin-resistant S. aureus (MRSA). Among the P. aeruginosa isolates, one obtained from a patient treated with EGF was multidrug-resistant. Patients treated with EGF had no infections during the follow-up period, and there was a significant difference between the 1st and 12th week in wound infection improvement in patients treated with PRP (P = .0078).

Characterization of Ciprofloxacin-Resistant and Ciprofloxacin-Susceptible Uropathogenic Escherichia coli Obtained from Patients with Gynecological Cancer.

The objective of this work was to assess the genetic characteristics of uropathogenic Escherichia coli, ciprofloxacin resistance or susceptibility, obtained from patients with gynecological cancer and urinary tract infection (UTI). Seventy-seven E. coli ciprofloxacin-resistant isolates and 38 ciprofloxacin-susceptible were analyzed by polymerase chain reaction (PCR) to determine the phylogenetic groups, virulence factors as iucC, fyuA, hlyC, cnf1 genes, and pks pathogenicity island. The presence of genes related to ciprofloxacin resistance such as qnrA, qnrB, qnrS, aac(6')-Ib-cr, and qepA, and the sequencing of DNA gyrase genes and topoisomerase IV were determined. The genetic profile of the isolates was determined by pulsed-field gel electrophoresis (PFGE). Statistical analysis was performed using Fisher's exact test and Chi-square test. Phylogenetic group B2 was the most prevalent although a great genetic diversity was observed by PFGE. Only genes associated to siderophores were found in ciprofloxacin-resistant isolates; however, in ciprofloxacin-susceptible isolates, genes related to siderophores and toxin, were detected. Additionally qnrB was detected in both populations, ciprofloxacin resistant and susceptible. DNA mutations in gyrA were Ser-83-Leu and Asp-87-Asn and in parC were Ser-80-Ile and Glu-84-Val, Glu-84-Lys. In conclusion, it was observed a high prevalence of qnrB in the population studied; in addition, it was the first time the pks island was observed only in ciprofloxacin-susceptible isolates.

Antimicrobial susceptibility and genetic diversity of Streptococcus agalactiae recovered from newborns and pregnant women in Brazil.

BACKGROUND: Streptococcus agalactiae is known to be the major cause of neonatal infections and also causes complications during pregnancy. METHODS: One hundred and six strains of Streptococcus agalactiae recovered from clinical specimens of newborns (n = 18) and pregnant women (n = 88) were submitted to antimicrobial susceptibility testing and investigation of genetic determinants of macrolide resistance, capsular type, and virulence factors. Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE) analysis. RESULTS: Strains were susceptible to ceftriaxone, levofloxacin, penicillin G, and vancomycin and resistant to tetracycline (85.8%) and erythromycin (4.7%). Erythromycin-resistant strains presented iMLSB phenotype, harbored the ermA gene, and were closely related by PFGE. Both bac and bca genes were found in low frequencies. PFGE analysis yielded 11 DNA restriction profiles among 35 selected isolates. The major clonal group, designated as A, was composed predominantly of strains belonging to capsular type Ia. Clonal group B was composed predominantly of strains with capsular type V, including all erythromycin-resistant isolates. CONCLUSIONS: Although low levels of erythromycin resistance have been observed, this is a fact of concern because this phenotype also confers resistance to clindamycin, an alternative agent for intrapartum prophylaxis. Despite the diversity of capsular types, Ia and V were among the most common and were significantly associated with distinct clonal groups. In a few cases, different capsular types were clustered into a single clonal group, which may be related to capsular switching.

Microbial diversity and anaerobic hydrocarbon degradation potential in an oil-contaminated mangrove sediment.

BACKGROUND: Mangrove forests are coastal wetlands that provide vital ecosystem services and serve as barriers against natural disasters like tsunamis, hurricanes and tropical storms. Mangroves harbour a large diversity of organisms, including microorganisms with important roles in nutrient cycling and availability. Due to tidal influence, mangroves are sites where crude oil from spills farther away can accumulate. The relationship between mangrove bacterial diversity and oil degradation in mangrove sediments remains poorly understood. RESULTS: Mangrove sediment was sampled from 0-5, 15-20 and 35-40 cm depth intervals from the Suruí River mangrove (Rio de Janeiro, Brazil), which has a history of oil contamination. DGGE fingerprinting for bamA, dsr and 16S rRNA encoding fragment genes, and qPCR analysis using dsr and 16S rRNA gene fragment revealed differences with sediment depth. CONCLUSIONS: Analysis of bacterial 16S rRNA gene diversity revealed changes with depth. DGGE for bamA and dsr genes shows that the anaerobic hydrocarbon-degrading community profile also changed between 5 and 15 cm depth, and is similar in the two deeper sediments, indicating that below 15 cm the anaerobic hydrocarbon-degrading community appears to be well established and homogeneous in this mangrove sediment. qPCR analysis revealed differences with sediment depth, with general bacterial abundance in the top layer (0-5 cm) being greater than in both deeper sediment layers (15-20 and 35-40 cm), which were similar to each other.

Antimicrobial resistance profiles and genetic characterisation of macrolide resistant isolates of Streptococcus agalactiae.

In this study, 100 clinical isolates of Streptococcus agalactiae recovered from genitourinary tract specimens of non-pregnant individuals living in Rio de Janeiro were submitted for antimicrobial susceptibility testing, detection of macrolide resistance genes and evaluation of the genetic diversity of erythromycin-resistant isolates. By agar diffusion method, all isolates were susceptible to ceftazidime, penicillin and vancomycin. Isolates were resistant to levofloxacin (1%), clindamycin (5%), erythromycin (11%) and tetracycline (83%) and were intermediated to erythromycin (4%) and tetracycline (6%). Erythromycin-resistant and intermediated isolates presented the following phenotypes: M (n = 3), constitutive macrolide-lincosamide-streptogramin B (MLS B, n = 5) and inductive MLS B (n = 7). Determinants of macrolide resistance genes, erm and mef, were detected in isolates presenting MLS B and M phenotypes, respectively. Randomly amplified polymorphic DNA profiles of erythromycin-resistant isolates were clustered into two major groups of similarity.

Detection of resistance genes and susceptibility patterns in Bacteroides and Parabacteroides strains.

Susceptibility to five antimicrobials was determined for Bacteroides spp. (n = 52) and Parabacteroides distasonis (n = 8). All isolates were susceptible to metronidazole. The resistance rates to ampicillin, cefoxitin, tetracycline and clindamycin were 98%, 9.6%, 65.3% and 19.2% of the Bacteroides strains, respectively. The genes cepA, cfiA, cfxA, tetQ, ermF and nim were found in 69.2%, 17.3% 9.6%, 50%, 7.7% and 3.8% for these strains respectively. All P. distasonis strains were resistant to ampicilin. Cefoxitin, tetracycline and clindamycin resistance rates were 75%, 87.5% and 50%, respectively. The ermF and nim genes were absent and 37.5%, 12.5%, 12.5% and 87.5% of this strains possessed cepA, cfiA, cfxA and tetQ genes, respectively. Ten cfiA gene positive strains of Bacteroides and Parabacteroides were submitted to E-test with imipenem and amoxicillin-clavulanate. The resistance rate to imipenem was 4.1% and 8.3% to amoxicillin-clavulanate. This feature is for the first time described in Brazil.

Enterotoxigenic and nontoxigenic Bacteroides fragilis strains isolated in Brazil.

The presence of enterotoxigenic Bacteroides fragilis and nontoxigenic B. fragilis (NTBF) among 109 strains isolated from 1980-2008 in Brazil were investigated by PCR. One strain, representing 0.9% of the total analyzed strains, harbored the bft gene which was identified as bft-1 isoform based on PCR-RFLP and sequencing. Forty-nine strains (44.9%) exhibited the NTBF pattern III which possesses the flanking region required for pathogenicity island acquisition in which the bft gene is codified. These data reinforce the potential of B. fragilis as an emerging enteropathogen in our country.

Non-toxigenic pattern II and III Bacteroides fragilis strains: coexistence in the same host.

Diarrhoeic stool samples from 334 0-5-year-old children were analysed with respect to the incidence of Bacteroides fragilis as well as other enteropathogens. B. fragilis was recovered in 9.3% (31/334) of the samples, and 79 strains were examined for the presence of the bft gene or the BfPAI flanking region using polymerase chain reaction assays. No enterotoxigenic B. fragilis strains were detected. In 29% (9/31) of the samples the coexistence of both II and III non-toxigenic B. fragilis (NTBF) patterns could be seen. In 51.6% (16/31) of the samples there existed a pattern II NTBF only, and in 19.4% (6/31) only pattern III could be detected. Strains from the same patient representing different patterns were submitted to pulsed-field gel electrophoresis assays. Fingerprints obtained by this technique showed that there was strong heterogeneity among strains from different individuals. However, different patterns from the same individual shared 100% similarity.

Antibacterial activity of thioetherhydroxyethylsulfonamide derivatives.

Thioetherhydroxyethylsulfonamide derivatives were synthesized and evaluated for their in vitro antibacterial activity against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923). Results have shown that compounds 8c and 9e display potent activity (MIC = 0.125 µg/mL) against E. coli when compared with the standard drug sulfamethoxazole (SMZ, MIC < 0.5 µg/mL) for this same strain. All the new compounds were fully identified and characterized by NMR ((1)H and (13)C) and X-ray crystallography (for compound 8c). This class of compounds can be considered as a good starting point for the development of new lead molecules in the fight against multi-drug bacterial resistance.

Association between the cfxA gene and transposon Tn4555 in Bacteroides distasonis strains and other Bacteroides species.

The Bacteroides genus, the most prevalent anaerobic bacteria of the intestinal tract, carries a plethora of the mobile elements, such as plasmids and conjugative and mobilizable transposons, which are probably responsible for the spreading of resistance genes. Production of beta-lactamases is the most important resistance mechanism including cephalosporin resistance to beta-lactam agents in species of the Bacteroides fragilis group. In our previous study, the cfxA gene was detected in B. distasonis species, which encodes a clinically significant broad-spectrum beta-lactamase responsible for widespread resistance to cefoxitin and other beta-lactams. Such gene has been associated with the mobilizable transposon Tn4555. Therefore, the aim of this study was to detect the association between the cfxA gene and the presence of transposon Tn4555 in 53 Bacteroides strains isolated in Rio de Janeiro, Brazil, by PCR assay. The cfxA gene was detected in 11 strains and the Tn4555 in 15. The transposon sequence revealed similarities of approximately 96% with the B. vulgatus sequence which has been deposited in GenBank. Hybridization assay was performed in attempt to detect the cfxA gene in the transposon. It was possible to associate the cfxA gene in 11 of 15 strains that harbored Tn4555. Among such strains, 9 presented the cfxA gene as well as Tn4555, but in 2 strains the cfxA gene was not detected by PCR assay. Our results confirm the involvement of Tn4555 in spreading the cfxA gene in Bacteroides species.

New PCR ribotypes of Clostridium difficile detected in children in Brazil: prevalent types of Clostridium difficile in Brazil.

A total of 35 Brazilian isolates of Clostridium difficile from faecal stools and four isolates from hospital environments were analyzed by PCR ribotyping. A whole cell protein profile (as an alternative for serogrouping), in vitro toxin production and susceptibility to vancomycin, metronidazole and clindamycin were also investigated. All strains were typeable by both phenotypic and genotypic methods, and a total of 13 different PCR ribotypes were identified, of which seven (132, 133, 134, 135, 136, 142 and 143) were considered new types and accounted for 78.5% of all samples evaluated (including hospital environments). A non-toxigenic C. difficile PCR ribotype 133 was detected in all children groups examined (inpatients, outpatients and healthy children), whilst toxigenic PCR ribotypes 015, 131, 134 and 135 were associated mostly with symptomatic children. Serogroups G and D were disseminated both in patients from the community and from the pediatric hospital, with group G prevalent among outpatient children. All strains were susceptible to vancomycin and metronidazole but high levels of resistance to clindamycin were found, especially among serogroups G and D. Co-existence of different ribotypes and serogroups in the same individual was observed. The new seven ribotypes found in this investigation may represent strains characteristic of this region of Brazil.

Antimicrobial resistance profiles and genetic characterisation of macrolide resistant isolates of Streptococcus agalactiae

In this study, 100 clinical isolates of Streptococcus agalactiae recovered from genitourinary tract specimens of non-pregnant individuals living in Rio de Janeiro were submitted for antimicrobial susceptibility testing, detection of macrolide resistance genes and evaluation of the genetic diversity of erythromycin-resistant isolates. By agar diffusion method, all isolates were susceptible to ceftazidime, penicillin and vancomycin. Isolates were resistant to levofloxacin (1 percent), clindamycin (5 percent), erythromycin (11 percent) and tetracycline (83 percent) and were intermediated to erythromycin (4 percent) and tetracycline (6 percent). Erythromycin-resistant and intermediated isolates presented the following phenotypes: M (n = 3), constitutive macrolide-lincosamide-streptogramin B (MLS B, n = 5) and inductive MLS B (n = 7). Determinants of macrolide resistance genes, erm and mef, were detected in isolates presenting MLS B and M phenotypes, respectively. Randomly amplified polymorphic DNA profiles of erythromycin-resistant isolates were clustered into two major groups of similarity.

Enterotoxigenic and nontoxigenic Bacteroides fragilis strains isolated in Brazil

The presence of enterotoxigenic Bacteroides fragilis and nontoxigenic B. fragilis (NTBF) among 109 strains isolated from 1980-2008 in Brazil were investigated by PCR. One strain, representing 0.9 percent of the total analyzed strains, harbored the bft gene which was identified as bft-1 isoform based on PCR-RFLP and sequencing. Forty-nine strains (44.9 percent) exhibited the NTBF pattern III which possesses the flanking region required for pathogenicity island acquisition in which the bftgene is codified. These data reinforce the potential of B. fragilis as an emerging enteropathogen in our country.