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Biomedical subjects

J F Lemeland

Publications and source records attributed to J F Lemeland.

At least 19 recordsLinked to original sources

Microbiologic contamination study of nebulizers after aerosol therapy in patients with cystic fibrosis.

BACKGROUND: To evaluate the contamination of delivery systems after an aerosol therapy session in patients with cystic fibrosis who have chronic Pseudomonas aeruginosa infection. METHODS: Fifty-three patients with cystic fibrosis were enrolled in the study from March 1996 to June 1997. All patients were age 7 years or older and had P aeruginosa infection. They also had been treated with recombinant deoxyribonuclease and were capable of producing sputum for culture. RESULTS: Nine devices were excluded for the study. A total of 44 nebulizers were included: 37 from patients with P aeruginosa colonization with a count of 10(6) colony-forming units/mL or more and 7 with a count of between 10(5) colony-forming units/mL and 10(6) colony-forming units/mL. CONCLUSION: This study demonstrates that in the absence of cleaning, nebulizers of patients with cystic fibrosis who are infected with P aeruginosa are likely to be contaminated by a pathogenic flora.

Aerosols↗

In vitro synergistic effects of double and triple combinations of beta-lactams, vancomycin, and netilmicin against methicillin-resistant Staphylococcus aureus strains.

Several studies have previously reported synergistic effects between vancomycin and a given beta-lactam or a given aminoglycoside against methicillin-resistant Staphylococcus aureus (MRSA) strains. The aim of our study was to exhaustively compare the effects of different combinations of a beta-lactam, vancomycin, and/or an aminoglycoside against 32 clinical MRSA strains with different aminoglycoside susceptibility patterns. The effects of 26 different beta-lactam-vancomycin and 8 different aminoglycoside-vancomycin combinations were first studied using a disk diffusion screening method. The best interactions with vancomycin were observed with either imipenem, cefazolin, or netilmicin. By checkerboard studies, imipenem-vancomycin and cefazolin-vancomycin each provided a synergistic bacteriostatic effect against 22 strains; the mean fractional inhibitory concentration (FIC) indexes were 0.35 and 0.46 for imipenem-vancomycin and cefazolin-vancomycin, respectively. The vancomycin-netilmicin combination provided an indifferent effect against all of the 32 strains tested; the mean of FIC index was 1. 096. The mean concentrations of imipenem, cefazolin, netilmicin, and vancomycin at which FIC indexes were calculated were clinically achievable. Killing experiments were then performed using imipenem, cefazolin, netilmicin, and vancomycin at one-half of the MIC, alone and in different combinations, against 10 strains. The vancomycin-netilmicin regimen was rarely bactericidal, even against strains susceptible to netilmicin. The imipenem-vancomycin and cefazolin-vancomycin combinations were strongly bactericidal against six and five strains, respectively. The addition of netilmicin markedly enhanced the killing activity of the combination of cefazolin or imipenem plus vancomycin, but only for the MRSA strains against which the beta-lactam-vancomycin combinations had no bactericidal effect. It is noteworthy that the latter strains were both susceptible to netilmicin and heterogeneously resistant to methicillin.

Anti-Bacterial Agents↗

PCR-Based assay for discrimination between invasive and contaminating Staphylococcus epidermidis strains.

The discrimination between Staphylococcus epidermidis strains that contaminate and infect blood cultures is a daily challenge for clinical laboratories. The results of PCR detection of putative virulence genes were compared for contaminating strains, sepsis-related strains, catheter strains, and saprophytic strains. Multiplex PCR was used to explore the atlE gene, which is involved in initial adherence, the intercellular adhesion gene cluster (ica), which mediates the formation of the biofilm, and the agrA, sarA, and mecA genes, which might contribute to the pathogenicity of S. epidermidis. Whereas the atlE, agrA, and sarA genes were almost ubiquitously amplified, the ica and mecA genes were detected significantly more in infecting strains than in contaminating strains (P </= 0.02) and thus appeared to be related to the potential virulence of S. epidermidis.

Bacterial Adhesion↗

Motility in the Roux-Y limb after distal gastrectomy: relation to the length of the limb and the afferent duodenojejunal segment--an experimental study.

Following gastrectomy, the longer is a Roux-Y limb constructed to restore digestive continuity the higher the frequency of postoperative symptoms. The aim of this experimental study was to test how the level of the jejunal transection and the length of the Roux limb affect the motility of the constructed limb and in particular the onset and the propagation of activity fronts (AFs). Three months after a distal Roux-en-Y gastrectomy, electromyographic tracings were recorded in six groups of rats grouped according to the level of the transection (20 or 40 cm from the pylorus) and the length of the limb (10, 20 or 30 cm). Animals in which a simple laparotomy or laparotomy + jejunal transection was performed, served as controls. During the interdigestive period, all animals had AFs in the limb which were independent from those recorded in the duodenum. In the limb, the mean time interval between two AFs was shorter (P < 0.01) and more irregular than in controls. An increase in limb length was associated with a lower incidence of completely propagated AFs (P < 0.05) and a higher incidence of irregularly propagated AFs (P < 0.01). When propagation of the AFs was analysed both in the limb and in the jejunum distal to the anastomosis, propagation abnormalities were more frequent. Below the gastrojejunal anastomosis, for an intestinal length of either 20 or 30 cm, the frequency of abnormal AFs was not different when this length was either only a limb or a limb with the 10 cm of distal jejunum below the jejuno-jejunal anastomosis. Interruption of AFs by a meal was irregular in the limb and more rarely observed in the 30-cm than in 10-cm limbs (P < 0.05). Interruption of AFs was shorter than in controls (P < 0.01). In the duodenum and the jejunum proximal to the limb, the interval between AFs was higher than in controls and in the Roux-Y limbs (P < 0.001). Intraluminal concentrations of bacterial strains were not different in the different types of limb while lactobacillus concentrations and pooled concentrations of bacteria were higher than in controls (P < 0.05). No relationship was found between the incidence of myoelectric abnormalities and intraluminal bacterial concentrations. Increasing the length of a Roux-Y limb resulted in more frequent disturbances in AFs in the limb but had no significant consequence on the overall rate of abnormal AFs in the jejunum distal to the transection. Motor response to food intake was also reduced. Motor changes were not related to intraluminal bacterial concentrations.

Anastomosis, Roux-en-Y↗

Usefulness of pulsed-field gel electrophoresis in assessing nosocomial transmission of pertussis.

During a 2-week period, three infants with a cough lasting at least 8 days with whoops, were admitted to the pediatric unit; Bordetella pertussis was isolated from nasopharyngeal aspirates collected from the three infants. Approximately 1 week later, a nurse working on the same unit developed influenza-like symptoms followed by whooping cough; B pertussis was isolated. Isolates from the nurse and from one of the infants were shown to be indistinguishable by pulsed-field gel electrophoresis. These data demonstrate that B pertussis transmission to healthcare workers is possible and emphasize the need to use respiratory protection devices (Droplet Precautions) for healthcare workers having close contact with infected children.

Adult↗

Nosocomial meningococcemia in a physician.

We report the case of a pediatrician who developed meningococcal meningitis after performing endotracheal intubation without protection on a child who was suspected of having meningoencephalitis. This case emphasizes the necessity for healthcare workers who perform high-risk procedures to use personal protection devices (i.e., respirators and protective goggles). Unprotected healthcare workers with high exposure to Neisseria meningitidis should receive chemoprophylaxis.

Adult↗

Evidence for nasal carriage of methicillin-resistant staphylococci colonizing intravascular devices.

Nasal surveillance cultures were performed for 54 patients exhibiting >/=10(3) CFU of methicillin-resistant coagulase-negative staphylococci per ml in central venous catheter (CVC) rinse cultures over a 6-month period. Forty-two of the nasal cultures yielded growth of methicillin-resistant coagulase-negative staphylococci, and 33 of the 42 cultures contained organisms that belonged to the same species as the CVC isolates. Of the 33 same-species isolates, 20 appeared to be identical strains by pulsed-field gel electrophoresis analysis. These data suggest that measures should be taken to reduce cross-contamination between the respiratory tract and intravascular devices. However, the potential interest in detecting methicillin-resistant coagulase-negative staphylococcus carriage in high-risk patients is hampered by the lack of sensitivity of nasal surveillance cultures.

Bacteremia↗

Molecular analysis of Mycobacterium avium isolates by using pulsed-field gel electrophoresis and PCR.

Genetic relationships among 46 isolates of Mycobacterium avium recovered from 37 patients in a 2,500-bed hospital from 1993 to 1998 were assessed by pulsed-field gel electrophoresis (PFGE) and PCR amplification of genomic sequences located between the repetitive elements IS1245 and IS1311. Each technique enabled the identification of 27 to 32 different patterns among the 46 isolates, confirming that the genetic heterogeneity of M. avium strains is high in a given community. Furthermore, this retrospective analysis of sporadic isolates allowed us (i) to suggest the existence of two remanent strains in our region, (ii) to raise the question of the possibility of nosocomial acquisition of M. avium strains, and (iii) to document laboratory contamination. The methods applied in the present study were found to be useful for the typing of M. avium isolates. In general, both methods yielded similar results for both related and unrelated isolates. However, the isolates in five of the six PCR clusters were distributed among two to three PFGE patterns, suggesting that this PCR-based method may have limitations for the analysis of strains with low insertion sequence copy numbers or for resolution of extended epidemiologic relationships.

Electrophoresis, Gel, Pulsed-Field↗

Nosocomial febrile illness in the elderly: frequency, causes, and risk factors.

BACKGROUND: Although nosocomial febrile illness (NFI) is common in hospitalized patients, it has been less extensively studied in the elderly. OBJECTIVE: To determine the frequency, causes, and risk factors of NFI in elderly inpatients. METHODS: This prospective study involved 608 patients (> or = 65 years of age) admitted in an acute geriatric unit. Investigators followed this cohort until 1 of the following events occurred: development of NFI, discharge from the geriatric unit, or death. The cause of NFI was classified into 3 groups: infectious, noninfectious, and no apparent diagnosis. We systematically studied 17 comorbid conditions, 6 drugs, and 7 invasive procedures. For comparison, the patients were stratified into 2 groups: patients with NFI and patients without NFI. RESULTS: Sixty-six patients (10.9%) with NFI were identified. They were compared with the remaining 542 patients without NFI. In 49 patients (74%) with NFI, the cause was infectious; in 9 (13.5%), it was noninfectious; and in 8 (12.5%), there was no apparent cause. After multivariate analysis, only fecal incontinence (odds ratio [OR], 5.54; 95% confidence interval [CI], 2.13-14.5), congestive heart failure (OR, 2.97; 95% CI, 1.53-5.76), and pressure ulcers (OR, 2.93; 95% CI, 1.19-7.17) were independent risk factors for NFI. The number of invasive procedures preceding the febrile episode was a significant predictor of infection (OR, 3.68; 95% CI, 1.14-9.21). CONCLUSIONS: Nosocomial febrile illness is a common event in elderly hospitalized patients. In 74% of the patients with NFI, an infection is found. Measures to decrease infectious NFI in the elderly require a reduction in the number of invasive procedures.

Aged↗

Group B streptococcal bacteraemia in the elderly.

The aim of this retrospective study was to determine the clinical spectrum of group B streptococcal (GBS) bacteraemia in patients over 70 years old. Sixty-six adults with GBS bacteraemia were reviewed over a 5-year period. Disease characteristics, clinical diagnoses and underlying disease were compared in 33 older patients (mean age 82.4 years) and 33 younger patients (mean age 54.2 years). The older patients were also compared with a control group (mean age 81.3 years). Urinary tract infection (39%), skin infection (33%) and pneumonia (24%) were the most frequent clinical diagnoses in older patients. Urinary tract infection (39% versus 6%) was significantly more frequent in older than in younger patients. One underlying disease and one condition were more frequent in elderly patients: congestive heart failure (39% versus 6%) and being bedridden (36% versus 0%). A comparison with the older control group showed that being bedridden was highly associated with GBS bacteraemia and was an important mortality factor amongst older patients (10% versus 30%). In conclusion, GBS disease in the elderly was found to be a severe clinical problem with a high mortality despite appropriate treatment.

Adult↗

Comparison of ATB staph, rapid ATB staph, Vitek, and E-test methods for detection of oxacillin heteroresistance in staphylococci possessing mecA.

The performance characteristics of the E-test (AB Biodisk, Solna, Sweden), the ATB Staph, the Rapid ATB Staph, and the Vitek GPS-503 card (bioMérieux, La Balme Les Grottes, France) methods for the detection of oxacillin resistance in a collection of staphylococci with a high proportion of troublesome strains were evaluated. Sixty-four Staphylococcus aureus strains and 76 coagulase-negative staphylococcal strains were tested. All strains were mecA positive and were characterized by the oxacillin agar screen plate test; 75 (53.6%) were found to be heterogeneous by a large-inoculum oxacillin disk diffusion assay, and oxacillin MICs for 89 (63.6%) were < or = 32 microg/ml. Three (4.7%) S. aureus strains and 25 (32.9%) coagulase-negative strains were classified as susceptible by the E-test, as defined by the National Committee for Clinical Laboratory Standards (NCCLS) oxacillin breakpoint (MIC < or = 2 microg/ml). The ATB Staph method failed to detect oxacillin resistance in 7 (11%) S. aureus isolates and 32 (42.1%) coagulase-negative isolates. The MICs for all but six of these discrepant isolates were < or = 16 microg/ml. The Rapid ATB Staph method was tested against S. aureus strains only and yielded 15 (23.4%) false-susceptible results for strains for which the MICs were < or = 32 microg/ml. The Vitek system was the best-performing system, since it failed to detect oxacillin resistance in only 3 (4.7%) S. aureus strains and 15 (19.7%) coagulase-negative strains, the MICs for all of which were < or = 2 microg/ml. These data indicate that (i) the performance of the two ATB Staph systems can be limited when the prevalence of borderline-heteroresistant staphylococci is high and (ii) the unreliability of the E-test and the Vitek methods for detecting resistant coagulase-negative strains might be reduced by the potential revision of the oxacillin breakpoint currently recommended by the NCCLS.

Bacterial Proteins↗

Lactobacillus species as emerging pathogens in neutropenic patients.

The intensive use of broad-spectrum antibiotics in the context of prolonged and severe neutropenia has contributed to the emergence of unusual pathogens. Four new cases of severe Lactobacillus infections-three of septicemia and one of pneumonia-are reported. They occurred in patients with acute leukemia who had chemotherapy-induced neutropenia. All patients were treated in the same intensive care unit and received the same antimicrobial prophylaxis which included a total bowel decontamination containing vancomycin. The four patients were treated with a combination of intravenous ceftazidime and vancomycin prior to the development of Lactobacillus infection. Improvement in the condition of all patients was obtained with a treatment including penicillin and concurrent recovery of granulopoiesis.

Adult↗

In vivo and in vitro activation and expansion of gammadelta T cells during Listeria monocytogenes infection in humans.

Serial flow cytometry analyses of peripheral blood mononuclear cells obtained from 8 patients infected with Listeria monocytogenes showed a higher percentage (P < 0.01) of gammadelta T cells (median, 11.7; range, 3.7 to 35.3) than did 16 age-matched uninfected controls (1.7, 0.4 to 13). Most in vivo-expanded gammadelta T cells expressed the Vgamma9 and Vdelta2 gene products and displayed a memory phenotype (CD45RO[high]), and patients' gammadelta T cells expressed significantly more (P < 0.01) activation marker HLA-DR than did controls (19.8% [median] and 0.9 to 87.6% [range] versus 2.3% and 0 to 4.7%, respectively). When peripheral blood mononuclear cells from normal donors were cultured in vitro with heat-killed Listeria cells, analysis of CD25 and HLA-DR expression on gammadelta and alphabeta T cells indicated that a high percentage of gammadelta T cells was activated early compared to alphabeta T cells. In addition, depletion of gammadelta T cells before culture abrogated the early lymphocyte proliferative response induced by the pathogen. Taken together, these results argue for the involvement of gammadelta T cells during L. monocytogenes infection in humans.

Adult↗

[Significance of the detection of fimbriae protein type adhesins on bacteria isolated in acute pyelonephritis in children].

A prospective bacteriological study in 50 children with acute pyelonephritis (APN) (32 girls and 18 boys) and 132 children with lower urinary tract infections (LUTI) (89 girls and 43 boys) was conducted from May to December 1993. Infection was defined by Kass' criteria and APN was defined by the clinical findings. C-Reactive Protein (CRP) assay and postcontrast computed tomography in the presence of a doubt concerning the diagnosis. Escherichia coli (EC) was the bacterial species most frequently isolated (76%). A systematic search for fimbriae protein adhesins (group PAP: pyelonephritis associated pil) on the EC was performed by haemagglutination (human group A red blood cells). 64% of EC possessed fimbriae protein adhesions in the APN group versus only 20% in the LUTI group. In children in whom an organic abnormality was demonstrated, the incidence of fimbriae protein-positive EC was 33% while in children with no organic abnormality, particularly without reflux, 89% of EC presented fimbriae protein. A statistically significant difference was demonstrated between these two groups (p < 0.01). The results of this study illustrate the important role of these adhesins in the development of APN. These adhesins facilitate countercurrent ascension of bacteria in the ureter towards the upper urinary tract and can make the bacteria resistant to certain antibiotics. Testing for fimbriae protein can be useful in clinical practice when investigating the aetiology of APN in the absence of demonstrated reflux. A latex test should soon be available to facilitate the detection of fimbriae protein.

Acute Disease↗

Clonal and temporal patterns of nasopharyngeal penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae stains in children attending a day care center.

The nasopharyngeal carriage of penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae (PSSp and PRSp, respectively) was analyzed in 116 children attending a day care center in Rouen, France, by three observation periods in November, January, and March of the winter of 1993 to 1994. The carriage rate of S. pneumoniae was found to be 47.7, 47.3, and 49.6% at each different observation period, and PRSp accounted for 42.2, 40.3, and 40.6% of pneumococcal isolates, respectively. The 52 isolates recovered in November were distributed in 34 electrophoretic types (ETs) by multilocus enzyme electrophoresis; 15 PRSp isolates, all of serotype 23F, belonged to a clonal complex of five ETs, representing the dominant population of PRSp in November. The temporal pattern of S. pneumoniae carriage was studied in 17 children who were colonized at the three periods by multilocus enzyme analysis of their isolates. The PSSp isolated, exhibiting distinct ETs, were transient only among these day care attendees. In contrast, most of the PRSp isolated in January and March belonged to the clonal complex. Thus, this PRSp population was resident in the day care center throughout the study period.

Carrier State↗