Search PubMed⌕ Search

Biomedical subjects

J D Cavallo

Publications and source records attributed to J D Cavallo.

At least 19 recordsLinked to original sources
PubMed2002

[Antibiotic sensitivity of Salmonella isolated in army hospitals between 1998-1999].

OBJECTIVES: Monitor the evolution in France of antibiotic sensitivity of non-typhoid salmonella isolated in fecal cultures conducted in army hospital laboratories. METHODS: A prospective study was performed from January 1998 to December 1999 in all the biology departments of the 11 army hospitals in France. All the non-repetitive strains were sent to an official center for serotyping and determination of the minimum inhibiting concentrations, by dilution in Mueller Hinton's gelose. The antibiotics currently used in treatment were tested and interpretation endpoints followed the recent recommendations of the Antibiogram committee of the French society of microbiology. Identification of beta-lactamase was conducted by iso-electric focalization and polymerization by chain reaction (PCR). For Salmonella Typhimurium, research for the specific resistance locus of the DT104 clone was made using PCR. RESULTS: Two hundred and twenty-two non-repetitive salmonella strains were isolated. The principle serotypes found were: Salmonella Enterididis (23.9%), S. Typhimurium (21.2%) and S. Hadar (10.8%). All the strains were sensitive to ciprofloxacin and cefotaxim, whereas one third exhibited reduced sensitivity to aminopenicillin. Depending on the serotype, Typhimurium and Hadar serotypes exhibited significantly lesser sensitivity to aminopenicillin, nalidixic acid and tetracycline. For S. Typhimurium, resistance is related to the diffusion of the multiresistant DT104 clone, which involves half of the strains of this serotype. For S. Hadar, 18 out of 24 strains (75%) were resistance to nalidixic acid, and 5 of them exhibited reduced resistance to ciprofloxacin. There was no difference in sensitivity to antibiotics between the strains responsible for diarrhea and those isolated in systematic examinations for capacity to work in the food trade (respectively 54 and 46% of strains). CONCLUSION: Non-typhoid salmonella are frequently isolated in diarrhea of infectious origin. The increasing resistance to antibiotics is primarily related to the diffusion of the DT104 clone, regarding S. Typhimurium and to the increase in resistance to quinolone, regarding S. Hadar.

Anti-Bacterial Agents↗
PubMed2002

Mechanisms of beta-lactam resistance in Pseudomonas aeruginosa: prevalence of OprM-overproducing strains in a French multicentre study (1997).

One hundred and forty-three non-repetitive strains of Pseudomonas aeruginosa were collected in 13 French hospitals in 1997. A decreased susceptibility or resistance to ticarcillin (MIC > 16 mg/L) was found in 61 isolates (43%) and this was attributed to three major mechanisms: (i) overexpression of OprM and hence related efflux components such as MexAB or MexXY (42.6%), (ii) production of acquired beta-lactamase (29.5%) and (iii) overexpression of chromosomally encoded AmpC cephalosporinase (21.3%). Four of seven 'intrinsically' resistant strains (11.5%) with normal amounts of OprM were shown to produce low levels of AmpC, whereas in three isolates no resistance mechanism to beta-lactams could be identified. Overproduction of OprM thus appears as an important mechanism of ticarcillin resistance in French isolates of P. aeruginosa.

Bacterial Outer Membrane Proteins↗
PubMed2001

[Correlation between sensitivity to fosfomycin and the presence of penicillinase PSE-1 in Pseudomonas aeruginosa].

A prospective survey was carried out during three three-weeks periods in May, October 1997 and October 1998 in 13 teaching hospitals. All non-repetitive isolates of P. aeruginosa collected were subject to serotypage and determination of the inhibiting minimal concentrations for ticarcillin, piperacillin, piperacillin + tazobactam, ceftazidime, imipenem, amikacin, ciprofloxacin and fosfomycin. Identification of the betalactamases and quantification of the cephalosporinase were done for the strains intermediate or resistant to ticarcillin. The most frequent serotypes were O: 6 (17%), O: 11 (13%), O: 1 (10%) and O: 12 (9%). Serotype O: 12 was the least susceptible to antibiotics except for fosfomycin. Whatever the serotype, 76% of P. aeruginosa strains with bla PSE-1 are susceptible to fosfomycin, when only 29.8% of non bla PSE-1 producing strains were susceptible to this antibiotic. Integron encoding bla PSE-1 could be implicated in susceptibility to fosfomycin of P. aeruginosa strains. The associations fosfomycin + imipenem or fosfomycin + ceftazidime could be proposed in case of infections due to P. aeruginosa O: 12.

Anti-Bacterial Agents↗
PubMed2001

[Survey of the antibiotic sensitivity of Pseudomonas aeruginosa in France and the distribution of beta-lactam resistance mechanisms: the GERPB 1999 study].

A prospective survey was carried out in october 1999 in 15 french teaching hospitals. Average susceptibility rates, determined by minimal inhibitory concentrations, for the 738 non-repetitive strains of P. aeruginosa isolated were: ticarcillin, 58%, ticarcillin + clavulanic acid, 56%, piperacillin, 73%, piperacillin + tazobactam, 82%, ceftazidime, 76%, cefepime, 53%, cefpirome, 36%, aztreonam, 58%, imipenem, 81%, amikacin, 62%, tobramycine, 71% and, ciprofloxacin, 60%. Among the 75% serotypable strains, the most frequent serotypes were: O:6 (15.3%), O:11 (14.5%), O:1 (10.4%), O:3 (7.9%), O:4 (6.1%) and O:12 (6.1%). The serotype O:12 was the most resistant to antibiotics. Forty-two percent of the strains were resistant or presented an intermediate susceptibility to ticarcillin. Mechanisms were as follow: 14.5% non enzymatic mechanism, 12.5% overproduction of the constitutive cephalosporinase, 7.1% transferable betalactamase and, 6.9% combination of these mechanisms. Among the 67 transferable betalactamases: 48 (71.6%) were PSE-1, 12 (19.4%) TEM-2 and 6 (7.5%) oxacillinases. One extended spectrum betalactamase was characterized. Among the cephalosporines tested, cefepime was less affected by the overproduction of constitutive cephalosporinase. Ceftazidime, remained the best cephalosporin except against the strains overexpressing the chromosomal type 1 beta-lactamase. Resistance to tobramycin was mainly due to enzymatic mechanisms with a high level of resistance. Decreased susceptibility was more frequent for amikacin than for tobramycin. This was probably related with non enzymatic mechanisms.

Academic Medical Centers↗
PubMed2001

Effect of beta-lactam antibiotics on the in vitro development of resistance in Pseudomonas aeruginosa.

OBJECTIVE: To investigate whether stepwise selection of resistance mutations may mirror the continued bacterial exposure to antibiotics that occurs in the clinical setting. METHODS: We examined the in vitro development of resistance to a number of commonly used antibiotics (cefepime, cefpirome, ceftazidime, cefotaxime, piperacillin and imipenem) in Pseudomonas aeruginosa, a significant nosocomial pathogen. Stepwise resistance was assessed by serial passage of colonies located nearest to the inhibition zone on antibiotic-containing gradient plates. RESULTS: The lowest frequencies of spontaneous resistance mutations were found with cefepime and imipenem; these drugs also resulted in the slowest appearance of resistance of spontaneous resistance mutations. In five wild-type P. aeruginosa strains, cefepime-selected isolates required a mean of 30 passages to reach resistance; resistance occurred more rapidly in strains selected with other cephalosporins. P. aeruginosa strains that produced beta-lactamase or non-enzymatic resistance generally developed resistance more rapidly than wild-type strains. For most strains, resistance to all antibiotics except imipenem correlated with increased levels of beta-lactamase activity. Cross-resistance of cephalosporin-selected resistant mutants to other cephalosporins was common. Cephalosporin-resistant strains retained susceptibility to imipenem and ciprofloxacin. CONCLUSIONS: From our in vitro study, we can conclude that the rate of development of resistance of P. aeruginosa is lower with cefepime compared with other cephalosporines.

Anti-Bacterial Agents↗
PubMed2001

Antibiotic susceptibility and mechanisms of erythromycin resistance in clinical isolates of Streptococcus agalactiae: French multicenter study.

Among 126 Streptococcus agalactiae isolates collected in 10 French laboratories in 1999, 27 (21.4%) had macrolide resistance related to the presence of erm(B) (11 strains), erm(A) subclass erm(TR) (10 strains), and mef(A) genes (2 strains) and the presence of combinations of erm(B) and erm(A) genes or mef(A) genes (3 strains).

Anti-Bacterial Agents↗
PubMed2001

[Evaluation of the OptiMal test in the diagnosis of imported malarial outbreak].

The OptiMal test is an immuno-chromatographic dipstick test that permits indiscriminate detection of Plasmodium falciparum and other species of human malaria. The purpose of this study was to evaluate the efficacy of the test for diagnosis of imported malaria. A total of 244 patients with a presumptive diagnosis of imported malaria in France were included during the study period. The reference test, i.e., combined thick and thin blood films, demonstrated infection by Plasmodium falciparum in 58 cases, Plasmodium vivax in 12, P. ovale in 8 and Plasmodium malariae in 2. The OptiMal test detected only 46 of the 55 Plasmodium falciparum cases. The sensitivity of the test for diagnosis of that species was 80%, its specificity was 98%, and its positive and negative predictive values were 95 and 93% respectively. Parsitemia studies showed poor test reliability for densities lower than 150/ul. Detection of other species was accurate in 21 out of 22. The results of this study demonstrate that the current version of the OptiMal test should be used with great caution for the diagnosis of malarial infection in hospital practice.

Chromatography↗
PubMed2001

[Anthrax].

Explore the source record for details and available documents.

Anthrax↗
PubMed2001

[Smallpox].

Explore the source record for details and available documents.

Antiviral Agents↗
PubMed2000

[Sensitivity to antibiotics of bacteria from nosocomial infections. Evolution in resuscitation services of military hospitals].

OBJECTIVE: The aim of this study, conducted in the French Military hospitals, was to monitor the course of the antimicrobial sensibility of bacteria isolated from nosocomial infection in intensive care units. PATIENTS AND METHODS: A prospective study has been conducted from January to December 1998 in all the intensive care units of the French Army. All the non-repetitive strains isolated from nosocomial infection were collected and sent to a reference centre. Antimicrobial susceptibility was determined by the agar dilution method. Beta-lactamase were identified by iso-electro-focalisation. Antibiotics choice and interpretative criteria were those of the "Comité Français de l'Antibiogramme de la Société Française de Microbiologie". RESULTS: A total of 849 strains are included in this study. Pseudomonas aeruginosa was the most frequently isolated bacterium (20%) followed by Escherichia coli (19%) Staphylococcus aureus (15%), coagulase-negative Staphylococci (CoNS) (11%) and Enterococci (7%). Imipenem was the most effective antibiotic against enterobacteriaceae (336 isolates; 100% susceptibility). Gentamicin (92%), amikacin (92%) third generation cephalosporins (83%), aztreonam (83%) and ciprofloxacin (78%) were also very effective. Resistance to III generation cephalosporins was correlated with an extended spectrum beta-lactamase (BLSE) in 36% of cases. This BLSE could be associated with an over production of the constitutive cephalosporinase. The most frequent species producing BLSE were Enterobacter aerogenes (75% of BLSE) and Klebsiella pneumoniae (17%). Among the 172 P. aeruginosa isolated, antimicrobial susceptibility were respectively: 71% for imipenem, 62%: tobramycin, 60%: amikacin 59%: ciprofloxacin 59% piperacillin + tazobactam, 55% piperacillin, 53%: ceftazidime and 44% for ticarcillin. Seventy per cent of the 96 CoNS and 50.2% of the 126 S. aureus isolated were resistant to methicillin. A strain of S. aureus and 2 CoNS strains had intermediate resistance to teicoplanin. Twenty per cent of the 59 Enterococci strains isolated were resistant to aminopenicillins (10/11 strains of E. faecium), and 9% presented a high level of resistance to gentamicine. One strain of E. faecium was resistant to vancomycin. CONCLUSION: The evolution of the susceptibility to antibiotics in intensive care units reflects the antibiotic pressure and level of cross-transmission. High rates of meticillin-resistance among staphylococci, of resistance to beta-lactams antibiotics among P. aeruginosa and of ciprofloxacin among Enterobacteriaceae are shown in this study. The implementation of appropriate strategies for surveillance and prevention is necessary.

Bacterial Infections↗
PubMed2000

In vitro activity of fusidic acid against streptococci isolated from skin and soft tissue infections.

The in vitro activity of fusidic acid was evaluated against 242 strains of streptococci isolated from skin and soft tissue infections during a prospective multicentre study. Nearly 90% of strains were isolated from dermatology, emergency and medicine units. Groups A, B, C and G streptococci represented, respectively, 41.9, 20.6, 4.4 and 27.8% of the strains. The activity of fusidic acid was dependent on the media used. MICs were generally one dilution lower with heart infusion agar than with Mueller-Hinton agar supplemented with 5% horse blood (MIC(90) for the whole streptococcal population = 8 mg/L and 16 mg/L, respectively). The distribution of MICs was unimodal and only two strains displayed MICs of fusidic acid >/= 64 mg/L. In both media, fusidic acid was moderately active against streptococci. However, antibiotic concentrations obtained in the skin exceed the MIC(90) of fusidic acid for streptococci, possibly explaining its clinical efficacy in the treatment of common cutaneous infections.

Anti-Bacterial Agents↗
PubMed2000

Antibiotic susceptibility and mechanisms of beta-lactam resistance in 1310 strains of pseudomonas aeruginosa: a French multicentre study (1996).

A total of 1310 consecutive strains of Pseudomonas aeruginosa were collected in 11 French hospitals in 1996. The percentages of susceptible isolates measured by the agar dilution method were: ticarcillin (53%), piperacillin (69%) (MIC 16 mg/L), ceftazidime (77%), cefepime (55%), cefpirome (40%), aztreonam (57.5%), imipenem (81.5%) (MIC 4 mg/L), amikacin (64.5%) (MIC 8 mg/L) and ciprofloxacin (58%) (MIC 1 mg/L). Resistance to beta-lactams was linked to the production of transferable beta-lactamases (30%), overproduction of cephalosporinase (29%) and to non-enzymic mechanisms (38%).

Anti-Bacterial Agents↗
PubMed2000

Characterization of VIM-2, a carbapenem-hydrolyzing metallo-beta-lactamase and its plasmid- and integron-borne gene from a Pseudomonas aeruginosa clinical isolate in France.

Pseudomonas aeruginosa COL-1 was identified in a blood culture of a 39-year-old-woman treated with imipenem in Marseilles, France, in 1996. This strain was resistant to beta-lactams, including ureidopenicillins, ticarcillin-clavulanic acid, cefepime, ceftazidime, imipenem, and meropenem, but remained susceptible to the monobactam aztreonam. The carbapenem-hydrolyzing beta-lactamase gene of P. aeruginosa COL-1 was cloned, sequenced, and expressed in Escherichia coli DH10B. The deduced 266-amino-acid protein was an Ambler class B beta-lactamase, with amino acid identities of 32% with B-II from Bacillus cereus; 31% with IMP-1 from several gram-negative rods in Japan, including P. aeruginosa; 27% with CcrA from Bacteroides fragilis; 24% with BlaB from Chryseobacterium meningosepticum; 24% with IND-1 from Chryseobacterium indologenes; 21% with CphA-1 from Aeromonas hydrophila; and 11% with L-1 from Stenotrophomonas maltophilia. It was most closely related to VIM-1 beta-lactamase recently reported from Italian P. aeruginosa clinical isolates (90% amino acid identity). Purified VIM-2 beta-lactamase had a pI of 5.6, a relative molecular mass of 29.7 kDa, and a broad substrate hydrolysis range, including penicillins, cephalosporins, cephamycins, oxacephamycins, and carbapenems, but not monobactams. As a metallo-beta-lactamase, its activity was zinc dependent and inhibited by EDTA (50% inhibitory concentration, 50 microM). VIM-2 conferred a resistance pattern to beta-lactams in E. coli DH10B that paralleled its in vitro hydrolytic properties, except for susceptibility to ureidopenicillins, carbapenems, and cefepime. bla(VIM-2) was located on a ca. 45-kb plasmid that in addition conferred resistance to sulfamides and that was not self-transmissible either from P. aeruginosa to E. coli or from E. coli to E. coli. bla(VIM-2) was the only gene cassette located within the variable region of a novel class 1 integron, In56, that was weakly related to the bla(VIM-1)-containing integron. VIM-2 is the second carbapenem-hydrolyzing metalloenzyme characterized from a P. aeruginosa isolate outside Japan.

Amino Acid Sequence↗
PubMed2000

[Surveillance of Pseudomonas aeruginosa sensitivity to antibiotics in France and distribution of beta-lactam resistance mechanisms: 1998 GERPB study].

In a prospective study carried out during a three-week period in October 1998 in 13 teaching hospitals, 735 non-repetitive isolates of Pseudomonas aeruginosa were collected. In patients presenting cystic fibrosis (70 strains), the main serotypes isolated were O:6 (14.3%) and O:1 (14.3%). Serotypes O:11 and O:12 were exceptional. In other patients (665 strains), the most frequent serotypes were O:6 (15.9%), O:11 (15.6%), O:1 (10.7%) and O:12 (9.2%). The antibiotic susceptibility rates were as follows (respectively, non-cystic fibrosis and cystic fibrosis strains): ticarcillin, 55 and 59%, piperacillin, 71 and 67%, ceftazidime, 75 and 67%, cefepime, 56 and 43%, cefpirome, 37 and 21%, aztreonam, 57 and 56%, imipenem, 83 and 70%, amikacin, 69 and 33%, ciprofloxacin, 56 and 61% and fosfomycin, 33 and 43%. Serotype O:12 was the least susceptible to antibiotics. Forty-five percent of the non-cystic fibrosis strains presented intermediate susceptibility or resistance to ticarcillin. The most frequent mechanisms of resistance were: non-enzymatic resistance (14.3%), overproduction of the constitutive cephalosporinase (13.8%), production of transferable beta-lactamase (8.6%) and a combination of these mechanisms (4.2%). Among cystic fibrosis strains, resistance to beta-lactam antibiotics was mainly due to overproduction of the constitutive cephalosporinase (18.6%), whereas production of a transferable beta-lactamase was rare (1.4%). Susceptibility to aminoglycosides and fluoroquinolones was less frequent in isolates producing transferable beta-lactamases and/or overproducing cephalosporinase. Decreased susceptibility to imipenem was more frequent in strains presenting a high level of cephalosporinase production. Among the cephalosporins, cefepime was the least affected by the overproduction of constitutive cephalosporinase. Ceftazidime remained the most efficient antibiotic against both susceptible isolates and strains presenting a non-enzymatic or PSE-1 penicillinase-producing mechanism.

Anti-Bacterial Agents↗
PubMed1999

[Urinary tract infection in an urban population: etiology and antibiotic sensitivity as a function of patient history].

OBJECTIVE: The aim of this study was to explore the relationship between etiological factors, bacterial isolates and Escherichia coli susceptibility to antibiotics in ambulatory patients with urinary tract infection. PATIENTS AND METHODS: A prospective study was conducted in 13 private medical laboratories in France in March 1998. Data were collected on 658 cases involving 679 strains in ambulatory patients with urinary tract infections. Data on age, gender, catheter insertion within the 7 preceding days, and history of hospitalization, urinary infection and antibiotic treatment during the 6 preceding months were recorded. The distribution of the bacterial isolates and Eschericha coli sensitivity to ciprofloxacin, cotrimoxazole, and gentamycin were studied. RESULTS: E. coli was most frequently isolated in women, in patients with no catheter or without a history of antibiotic treatment, hospitalization or urinary infection. There was no difference in E. coli sensitivity according to sex and age in women. In patients with prior antibiotic treatment, all the tested antibiotics except gentamycin were significantly less active. In case of prior hospitalization, the E. coli isolates were more resistant to amoxicillin, quinolones, cotrimoxazole and gentamycin. The level of E. coli suceptibility rose as the delay since hospitalization or urinary infection increased. CONCLUSION: Ambulatory patients comprise a heterogeneous population requiring particular attention to correctly adapt therapeutic strategies.

Adolescent↗
PubMed1999

Bacillus thuringiensis serotype H34 isolated from human and insecticidal strains serotypes 3a3b and H14 can lead to death of immunocompetent mice after pulmonary infection.

In 1995, we isolated a strain of Bacillus thuringiensis serotype H34 from severe human tissue necrosis. This bacterium was able to induce myonecrosis in immunosuppressed mice after cutaneous infection. Its potential pathogenicity for immunocompetent hosts was investigated in a mouse model of pulmonary infection. Mice infected intranasally by a suspension containing 10(8) spores died within 8 h in a clinical toxic-shock syndrome. In the same conditions, infection with a mutant without crystalline toxin, with the supernatant from a culture containing 10(8) bacteria ml(-1) and by the insecticidal strain serotypes 3a3b or H14 led to identical results. Lower inocula simply induced a local inflammatory reaction with bacterial persistence observed during the course of 10 days.

Animals↗