Biomedical subjects

M C Ploy

Publications and source records attributed to M C Ploy.

29 records · Page 2Linked to original sources

PubMed1995

[Evolution of the susceptibility to penicillin G of Streptococcus pneumoniae at the Limoge University Hospital Center].

A systematic detection of Streptococcus pneumoniae strains with reduced susceptibility to penicillin has been realized at Limoges Hospital during two years half. Of 302 strains isolated, 27 had reduced susceptibility to penicillin (8,9%), and, for 15 strains (5%), the MIC of penicillin G reached at least 2 mg/l. The frequency of strains with reduced susceptibility to penicillin increased from 1992 to 1994: 8,2% in 1992, 8,7% in 1993 and 12,2% in 1994. The resistance level exhibited by pneumococcus strains increased since 1992: the percentage of resistant strains (MIC mg/l > 1) was 2,7% in 1992, 6,9% in 1993 and 7,3% in 1994. Most of the strains with reduced susceptibility to penicillin belonged to serotype 23 (52%) and were isolated from blood cultures, cerebral-spinal or pleural fluids (41%).

France↗

PubMed1995

[Dynamics of the nasal colonization by methicillin resistant Staphylococcus aureus in patients hospitalized in an intensive care unit].

Prospective study on MRSA nasal cariage was done during two months in an intensive care unit in Limoges University Hospital. Nasal swab specimens were taken daily and cultured on selective and non selective media. Sixty eight patients were included in this study (878 swab collected, 575 MRSA isolated). Patients mean âge was 62 years and stay period mean was 12.3 days (median: 7 days). Among these patients, 16 were already carrying MRSA when entering in the unit and 26 became positive for MRSA during their stay. The mean colonisation delay was 5.5 days (median 4 days). All patients, except one, have shown a nasal carriage during all their stay. During the study period, 17 patients became infected and only two patients neither carried nasal MRSA before and during infection. In all cases, glycopeptide treatment did not affect nasal carriage. Colonisation and infection risk factors were discussed.

Adolescent↗

PubMed1995

[Adenoviruses from stool samples in hospital units. Comparison with main pathogens in gastroenteritis (rotavirus, Campylobacter, Salmonella)].

During a six-years period (1988-1993), a total of 14,644 stool samples from in-patients of Limoges University Hospital were examined for the presence of principal enteric pathogens, such as adenovirus, rotavirus, Campylobacter, Salmonella, Shigella and others. Stools were processed for identification of bacteria by standard methods and viruses were detected in fecal specimens using antigen detection methods: ELISA (Enzyme Linked Immunosorbent Assay) and latex agglutination test. The decreasing rates of presence of enteric agents were respectively 6% for rotavirus, 3.2% for Salmonella, 2% for adenovirus, 1.6% for Campylobacter and 0.2% for Shigella, but according to the lack of sensibility of latex agglutination test, adenovirus prevalence was probably underestimated. Concerning the distribution of enteric pathogens throughout the year, our data demonstrate that rotavirus were rather shed during the months from January to April, adenovirus between April and August, Campylobacter during summer and Salmonella from July to October. The two thirds of Campylobacter and rotavirus infections and the half of adenovirus and Salmonella infections were identified during the ten first years of life. The highest prevalence occurs before 5 years old, during the 2nd year of life for adenovirus (4.4%) and rotavirus (22.3%) and during the 3rd year of life for Campylobacter (6.84%) and Salmonella (8.6%).

Adenovirus Infections, Human↗

PubMed1994

A spontaneous point mutation in the aac(6')-Ib' gene results in altered substrate specificity of aminoglycoside 6'-N-acetyltransferase of a Pseudomonas fluorescens strain.

The aac(6')-Ib' gene from Pseudomonas fluorescens BM2687, encoding an aminoglycoside 6'-N-acetyltransferase type II which confers resistance to gentamicin but not to amikacin, was characterized. Nucleotide sequence determination indicated total identity between aac(6')-Ib' and the aac(6')-Ib gene from Pseudomonas aeruginosa BM2656 [1] with the exception of a C-to-T transition that results in a serine to leucine substitution at position 83 of the deduced polypeptide. The aac(6')-Ib gene specifies a type I enzyme which confers resistance to amikacin but not to gentamicin [2]. It thus appears that the point mutation detected is responsible for enzymic altered substrate specificity.

Acetyltransferases↗

PubMed1994

Detection of aac(6')-I genes in amikacin-resistant Acinetobacter spp. by PCR.

The distribution of aac(6')-I genes in 62 strains of Acinetobacter spp. resistant to amikacin, netilmicin, and tobramycin and susceptible to gentamicin, a phenotype compatible with synthesis of an AAC(6')-I enzyme, was studied by PCR and by DNA hybridization. Both methods gave similar results. Among the 51 Acinetobacter baumannii strains, aac(6')-Ib was found in 19 isolates and aac(6')-Ih was found in the remaining strains. The aac(6')-Ig gene was present in all 10 A. haemolyticus strains studied and was detected only in this species. A pair of degenerate oligonucleotides complementary to conserved regions of aac(6')-Ic, -Id, -If, -Ig, and -Ih enabled detection of these genes and also of aac(6')-Ij, recently recognized in Acinetobacter sp. strain 13.

Acinetobacter↗

PubMed1994

[Antibacterial activity of clarithromycin and its hydroxylated derivative and two other macrolides against thirty strains of Streptococcus pneumoniae].

Macrolides are widely used in the treatment of respiratory infections. Here, the authors compared the activity of different 14-membered macrolides: erythromycin (Ery), roxithromycin (Rox), clarithromycin (Cla) and its 14-hydroxy metabolite 14-OH clarithromycin (14-OH) against 30 strains of Streptococcus pneumoniae isolated at the Dupuytren hospital (Limoges, France) from upper respiratory tract sputum, ophthalmic sputum, blood samples and CSF. Twenty strains were susceptible to macrolides and 10 were resistant. Three strains from the susceptible and 7 from the resistant were resistant to penicillin. Furthermore, for all the macrolides except Rox and 14-OH, susceptibility tests were performed by the disk diffusion method on Mueller-Hinton agar. MICs50 of Cla and Ery were 0.06 mg/l. They were two-fold increased for 14-OH (0.125 mg/l) and four-fold increased for Rox (0.25 mg/l). We noted that for 3 resistant strains, MICs of Cla were four-fold decreased than MICs of Ery. Ery, Cla and 14-OH had bactericidal activity against pneumococcus strains susceptible to these antibiotics at 4 and 8 times the MIC after 6 or 18 h. The difference between MIC and MBC was small (1 or 2 two-fold dilutions) for Ery, Rox and Cla. For 14-OH, this difference was within 2 to 4 two-fold dilutions. The bactericidal activity is similar to that of amoxicillin and cefotaxim. A microdilution chequeboard technique was used against 3 strains and the FIC index did not show synergistic effect of combining Cla and 14-OH. The activity of Cla and 14-OH against 5 strains was not modified in the presence of 50% fresh pooled human serum inactivated at 56 degrees C or not.

Anti-Bacterial Agents↗

PubMed1992

[Study of intraocular diffusion of ofloxacin in humans and rabbits].

The diffusion of ofloxacin in infected and healthy human and rabbit eyes was investigated. In the human study, cataract surgery patients were given intravenous ofloxacin either as a single 200 or 400 mg dose or as two 400 mg infusions 12 hours apart. Samples of aqueous humor and plasma were collected between 1 and 12 hours after the end of the infusion. Levels in the anterior chamber increased with the dose; peak levels, which occurred after three hours, were 0.33 mg/l after 200 mg and 1.24 mg/l after two 200 mg doses given 12 hours apart. In the rabbit study, 16 hours after experimental infection of the left eye by injection of S. epidermidis into the vitreous, animals were given an intraperitoneal injection of 20 or 50 mg/kg ofloxacin. Dosages in the various ocular tissues showed that penetration into the eye varied with race (albinos greater than pigmented) and dose. Intraocular ofloxacin levels, including in the vitreous, increased two fold when the eye was infected; however, penetration into the sclera, choroid, and retina was comparable in infected and noninfected eyes. These findings in humans and animals suggest that ofloxacin in a dose of a least 400 mg is a useful agent for the treatment of prophylaxis of ocular infections.

Aged↗

PubMed1992

[Diffusion of piperacillin in the eye].

Intraocular diffusion of piperacillin was studied in 42 patients scheduled for cataract surgery (n = 35) or vitrectomy (n = 7). Piperacillin was administered intravenously (4 g/injection). Thirty-four patients were given a single dose and 8 were given two doses 12 hours apart. Peak piperacillin levels in the aqueous (7.3 mg/l) occurred one hour after the injection; levels in the vitreous were low (less than 0.6 mg/l). Intraocular diffusion of piperacillin was also studied in rabbits with an experimental Staphylococcus epidermidis infection of one eye; the other eye served as the control. In pigmented rabbits (6 Fauve de Bourgogne animals), increased diffusion and decreased elimination of piperacillin were seen in the aqueous, iris and cornea of the infected eyes, as compared with uninfected control eyes. In albino rabbits (6 New Zealand animals), results were less conclusive, with a difference between the infected and healthy eyes appearing only during the second hour following the injection. The good diffusion of piperacillin in the aqueous, especially in infected eyes (at least in rabbits), suggests that this drug may be useful for the treatment of ocular infections provided it is initiated early and given in combination with another antimicrobial exhibiting good intraocular diffusion.

Aged↗

PubMedDate not supplied

[Ocular bacterial infections : present and prospective methods of diagnosis].

Bacteriological samples and tests are essentiel for the diagnosis of superficial ocular infections and endophtalmitis. The direct examination and the traditional culture of the samples can be in the futur associated with new diagnostic approach using antigen detection (immunofluorescence, enzyme immunosorbent assays) and genome research by hybridation or better by amplification for Chlamydia and for the most frequent species responsible of endophtalmitis. An original genomic strategy of bacterial endophtalmitis diagnosis was developped.

Antigens, Bacterial↗

PubMedDate not supplied

[The role of integrons in dissemination of antibiotic resistance].

Bacteria can transfer genetic information to get protection against most antibiotics. The acquisition of resistance genes involves genetic mobile elements such as plasmids and transposons. Another genetic structures, named integrons, have been described and contain one or more gene cassettes located at a specific site. Integrons contain an intI gene encoding a site-specific recombinase belonging to the integrase family and a recombination site attI. A gene cassette includes an open reading frame and, at the 3'-end, a recombination site attC. Integration or excision of cassettes occurs by a site-specific recombination mechanism catalyzed by the integrase. However, insertion can rarely occur, at non-specific sites leading to a stable situation for the cassette. Cassettes are transcribed from a common promoter located in the 5'-conserved segment and expression of distal genes is reduced by the presence of upstream cassettes. Most gene cassettes encode antibiotic resistant determinants but antiseptic resistant genes have also been described. Integrons seem to have a major role in the spread of multidrug resistance in Gram-negative bacteria but integrons in Gram-positive bacteria have been recently described. Moreover, the finding of super-integrons with gene cassettes coding for other determinants (biochemical functions, virulence factors) in different Gram negative bacteria suggests that integrons are probably implied in bacterial genome evolution.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Virus and gastrointestinal infections].

Numerous viruses found in the gut are not associated with primary infection or disease of the gastrointestinal tract. Other groups or viruses are not classically associated with infection of the gut but can infect the gastrointestinal tract in immunocompromised individuals (herpes simplex virus, cytomegalovirus, papillomavirus ....). The viruses associated with gastroenteritis represent a large number of taxonomic group. Because these viruses have in general been difficult to cultivate, most members of this group were firstly detected by electron microscopic examination (adenovirus, astrovirus, calicivirus, coronavirus, rotavirus ....). The most widely used diagnostic techniques for adenovirus (40/41), rotavirus and astrovirus detection in faecal samples include immunoassays such as Elisa and latex agglutination. Nucleic acid hybridization techniques have generally not proven to be substantially sensitive and the more sensitive techniques recently developed use the polymerase chain reaction (adenovirus) or the reverse transcription/polymerase chain reaction (astrovirus, calicivirus, coronavirus, rotavirus). Special efforts have been made in the search for efficient procedures to extract viral nucleic acids, and to establish the optimal conditions for the amplification and identification of PCR products but the candidate viruses were very different, consensus procedures were not determined, and amplification kits were not actually commercialized.

Clinical Laboratory Techniques↗