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Biomedical subjects

P L Petit

Publications and source records attributed to P L Petit.

At least 19 recordsLinked to original sources
PubMed2004

[Community-acquired pneumonia: pathogens and course in patients admitted to a general hospital].

OBJECTIVE: To determine prognostic factors and the significance of (non-invasive) microbiological tests for the clinical course of patients admitted to one general hospital with community-acquired pneumonia (CAP). DESIGN: Prospective observational study. METHOD: Patients admitted to one location of a general hospital with symptoms of CAP during the period January 1998-December 1999 were included. Data from the anamnesis, physical examination and laboratory tests were recorded and samples were taken for diagnosis of the possible pathogens. Cultures were made of sputum and blood, serum and sputum were examined for infection with viral and atypical microorganisms, and the urine was screened for Streptococcus pneumoniae and Legionella antigens. RESULTS: Of the 157 patients studied, 28 (18%) died as a direct result of CAP. In a stepwise multivariate analysis, age > or = 65 years, increased serum-creatinine levels and hypercapnia were independent predictors of mortality. Streptococcus pneumoniae and Haemophilus influenzae were detected 53 and 19 times, respectively, and were the bacterial pathogens most frequently found. Among the nonbacterial pathogens, Mycoplasma pneumoniae was found 37 times and serologic tests for influenza A or B virus were positive in 34 cases. In 62 patients (39%), extensive microbiological tests revealed signs of a combined infection and in 20 patients (13%) no microorganism could be detected. An elevated serum-procalcitonin level was associated with bacterial infections. As a consequence of their retrospective nature, the results of the extensive serological tests did not contribute to reaching a diagnosis in daily clinical practice. In comparison with the literature, there was a markedly high number of subclinical or atypical infections with Legionella (8%) and Bordetella (18%) and a high incidence of viral and atypical microorganisms as the cause of CAP.

Adult↗
PubMed2001

Microbiological screening of post-mortem bone donors - two case reports.

This study assesses the value of blood cultures in combination with swab culturing techniques in association with bone banking procedures. The results of blood and swab cultures of two postmortem bone donors were compared with procured grafts, cultured in their entirety. In one donor, who died of drowning, three of the 12 entire graft cultures were positive with the same microorganism of high pathogenicity as the blood culture, whilst the swab culture of only one graft was positive. In the second donor, who died from myocardial infarction, four entire cultures were positive with the same organism of high pathogenicity as the blood culture, whilst the swab cultures of three grafts were positive. In both donors identical organisms were cultured from the myocardium of the pulmonary or aortic heart valve. The results confirm the limited sensitivity of swab culturing techniques. Especially micro-organisms inside a graft, disseminated through the bloodstream, can remain unnoticed. Blood cultures seem to provide additional information on micro-organisms that have spread haematogenously pre-mortem and may even provide information on the source from which they have spread.

Adult↗
PubMed2000

Increasing resistance to fluoroquinolones in escherichia coli from urinary tract infections in the netherlands.

In continuous surveillance of routine samples from five Dutch laboratories, we studied resistance to the antibiotics most commonly prescribed for urinary tract infections (UTI) in The Netherlands, namely norfloxacin, amoxycillin, trimethoprim and nitrofurantoin, from 1989 to 1998 in >90000 Escherichia coli isolates. Resistance to norfloxacin increased from 1.3% in 1989 to 5.8% in 1998. Multiresistance, defined as resistance to norfloxacin and at least two of the other three antibiotics, increased from 0.5% in 1989 to 4. 0% in 1998. Multivariate analysis of the norfloxacin resistance demonstrated that this yearly increase (the odds ratio was 1.0 in 1989, 1.6 in 1992, 2.9 in 1995 and 6.1 in 1998) was independent of other determinants of resistance to norfloxacin, such as age, gender and origin of the isolate. Analysis of strata, classified by year, age and gender, demonstrated an association between prescription of fluoroquinolones (defined daily doses per case of UTI) and resistance to norfloxacin in E. coli (P < 0.001). There was no significant association with the prescription of nitrofuran derivatives (nitrofurantoin) and trimethoprim with or without sulphamethoxazole. The yearly increase of resistance to fluoroquinolones in E. coli from UTI may stem from increased prescription of fluoroquinolones for UTI. Resistance of E. coli to these agents is likely to increase further as fluoroquinolone use increases in future.

Adolescent↗
PubMed1999

A comparative study of blood and bone marrow cultures in cadaveric bone donation.

The results of blood cultures taken from cadaveric bone donors were compared with bone marrow and also swab cultures of the procured grafts. In eight of the 95 donors evaluated, pathogenic micro-organisms were detected in the blood sample. In two, identical micro-organisms were cultured from the blood and bone marrow sample whilst the swab cultures were negative. Considering the low sensitivity of the swab culture, the organisms detected in the blood culture were likely to have spread haematogenously and considered to be present in the explanted grafts. Bacteriological screening of bone donors is extremely important since the transmission of micro-organisms via an allograft can lead to serious complications in the recipient. Positive blood cultures provide important information on the presence of pathogenic micro-organisms in grafts obtained from cadaveric bone donors and are therefore essential in deciding whether a graft is bacteriologically acceptable for transplantation.

Blood↗
PubMed1998

Resistance of staphylococci in The Netherlands: surveillance by an electronic network during 1989-1995.

An electronic surveillance network for monitoring antibiotic resistance in The Netherlands has been in operation since 1989. Seven public health laboratories participate and the system covers about 25% of all bacteriological determinations in The Netherlands. This paper reports the results of staphylococci isolated in the period 1989-1995. About 0.3% of the Staphylococcus aureus isolates in the study period were resistant to methicillin. This low percentage may be due to the restrictive use of antibiotics and to strict isolation measures aimed at eradicating methicillin-resistant S. aureus. Low frequencies of resistance among methicillin-resistant S. aureus were found for vancomycin (0%), chloramphenicol (11%), cotrimoxazole (11%), mupirocin (3% low-level resistance) and fusidic acid (7%). Twenty-one percent of the coagulase-negative staphylococci were resistant to methicillin. Low frequencies of resistance among these methicillin-resistant coagulase-negative staphylococci were those to vancomycin (0.4%), nitrofurantoin (2%), doxycycline (20%) and amikacin (20%). Coagulase-negative staphylococci from cerebrospinal fluid, blood and skin were less often resistant to quinolones than isolates from respiratory tract, faeces and urine. A significant increase in resistance of coagulase-negative staphylococci to methicillin, erythromycin, gentamicin and ciprofloxacin was observed in the investigated period but the resistance to doxycycline and co-trimoxazole decreased in the last few years. To confirm the determination of methicillin resistance and coagulase production, a PCR method was developed which detects both the mecA and the coagulase gene. The results of the PCR method correlated well with the methicillin MIC as determined by an agar-dilution method.

Anti-Bacterial Agents↗
PubMed1998

Left ventricular loading modifications induced by pneumoperitoneum: a time course echocardiographic study.

UNLABELLED: The intraperitoneal insufflation of carbon dioxide during laparoscopic procedures is associated with an increase in mean arterial pressure and systemic vascular resistance. To evaluate the time course of the circulatory changes related to intraabdominal pressure variation, we used transesophageal echocardiography in 10 patients anesthetized for laparoscopic cholecystectomy. Left ventricular dimensions, fractional area shortening (FAS), and left ventricular afterload assessed by the left ventricular end-systolic wall stress (LVESWS) were measured from echocardiographic data before insufflation, during pneumoperitoneum, and during exsufflation. Three minutes after the onset of pneumoperitoneum, we observed a 25.7% +/- 10.5% (mean +/- SD) increase in mean arterial pressure, a 49.1% +/- 14.4% increase in LVESWS, and a 17.0% +/- 16.2% decrease in FAS. All measured variables returned to preinsufflation values after 30 min of pneumoperitoneum and thereafter were no longer significantly affected by postural changes (10 degrees head-up position) or pneumoperitoneum exsufflation. We conclude that the circulatory changes associated with pneumoperitoneum are transient and are probably mediated by factors other than intraabdominal pressure variations. IMPLICATIONS: Insufflation of gas into the abdominal cavity results in hemodynamic changes during laparoscopic procedures. We found that echocardiographic and blood pressure effects associated with gas insufflation were transient, indicating mediation by factors besides intraabdominal pressure.

Adult↗
PubMed1997

Contamination of bone allografts: analysis of incidence and predisposing factors.

We analysed the bacterial contamination of 1999 bone allografts retrieved from 200 cadaver donors under sterile operating conditions. The effect of various factors on the relative risk of contamination was estimated using a multiple logistic regression model. Organisms of low pathogenicity were cultured from 50% of the grafts and of high pathogenicity from 3%. The risk of contamination with low pathogenic organisms (mainly skin commensals) increased by a factor of 1.6 for each member added to the procurement team. The risk of contamination with high pathogenic organisms (mainly contaminants from the gastrointestinal tract) was 3.4 times higher in donors with a traumatic cause of death and 5.2 times higher in those with a positive blood culture. Preceding organ procurement did not significantly influence the risk of contamination. Rinsing the graft with an antibiotic solution was not an effective decontamination method. The major source of contamination is exogenous and is strongly influenced by the procurement team. Contamination from endogenous sources can be controlled by donor selection. We discuss methods that can be used to decrease contamination and the rate of discarding of bone allografts.

Anti-Bacterial Agents↗
PubMed1996

Antibiotic resistance mechanisms in Salmonella species causing bacteraemia in Malawi and Kenya.

In two studies on the causative agents of bacteraemia in Malawi and Kenya, 33 Salmonella strains were isolated. Fourteen strains of Salmonella typhimurium and Salmonella enteritidis were found to exhibit resistance to amoxicillin, amoxicillin/clavulanic acid and cotrimoxazole as well as decreased susceptibility to a range of aminoglycosides. The resistant strains were studied to establish their resistance mechanisms. Beta-lactamase co-focusing with TEM-1 was present in 12 strains. In two strains, both S. typhimurium from Kenya, an OXA-1 beta-lactamase was detected. The aminoglycoside-modifying enzyme ANT(2") was found in 10 strains. The presence of the encoding genes was confirmed by PCR. For comparison, susceptibility records of 73 Salmonella strains isolated during the past 14 years in our hospital were studied retrospectively. Only one of these strains was resistant to amoxicillin. This resistance was acquired during therapy.

Ampicillin Resistance↗
PubMed1995

Analysis of hospital records in four African countries, 1975-1990, with emphasis on infectious diseases.

Detailed standardized annual reports are analysed for 17 rural hospitals in four African countries, with admission figures of 1.2 million patients (excluding deliveries) and more than 67,000 deaths over a period of 16 years. The countries involved are Zambia, Tanzania, Kenya and Ghana. Figures on admission, causes of death and clinical case fatality rates are presented per country and per 4-year calendar period for the most important infectious diseases. The number of admissions increased substantially in 3 of the 4 countries (50-77%) between 1976 and 1990, but admission rates (per 1,000 population per year) by much less (6-25%), indicating that a large part of the increase in the volume of services was due to population growth. The number of infectious disease admissions in Ghana, however, decreased by 12% and even more in terms of admission rates (by 42%). About 75% of all admissions in children below 15 years of age were due to infections and infection related diseases; for adults this figure was 31%. Malaria is the single most important infectious disease both in terms of admissions and as a cause of death; it has increased substantially in three of the four countries. Bacterial infections, in particular pneumonia, gastroenteritis, meningitis and tuberculosis, are also important diseases in terms of admissions and deaths. On the whole they have remained at more or less the same level in 1975-1990 in terms of both admissions and deaths. Immunizable diseases and measles, once important as causes of admissions and deaths, have declined in all countries. Case fatality rates vary substantially by type of disease. They are very high for tetanus (36.7-68.8%) and meningitis (14.7-43%), and low for malaria (0.6-4.6%). However, they vary considerably in the four countries included in the study and are usually lower in children than in adults. A need for detailed studies with good "standardized" hospital records is emphasized. Representative data are needed from all hospitals in a given catchment area, with defined diagnoses for diseases and details regarding age and sex. This kind of information is highly desirable for planning and operation of curative and preventive medical care in developing countries.

Adolescent↗
PubMed1995

Bacteraemia in patients presenting with fever.

In three studies, in Ghana and Kenya, blood from 639 patients admitted with fever was cultured. Standard treatments were antimalarials (54-100%) and antibiotics (39-90%). According to the criteria in use, however, only 10-31% had malaria alone; of those who received antibiotics, 66% were diagnosed with malaria, gastrointestinal infections, post-operative recuperations, circulatory problems, central nervous system disorders or FUO, and did not need antibiotics at the first encounter. For those with wounds and abscesses (8%), generalised antibiotic treatment can also be questioned. Bacteraemia was found in 71 (11.3%) patients; in the HIV patients, however, 5 (23%) of 22 had bacteraemia. This is a minimum incidence, since culture techniques were not optimal for the isolation of fastidious microorganisms. The most prevalent organisms isolated were Salmonella, Klebsiella/Enterobacter and S. aureus. Resistance (intrinsic and extrinsic) in the Gram- bacteria was high: 31-100% were resistant to amoxycillin, 0-80% to cotrimoxazole, 15-95% to chloramphenicol and 9-15% to gentamicin. The need for cultures and sensitivity tests for patients with prolonged or undiagnosed fever is stressed. Specific treatment should be given only when infections, whether malarial or bacterial, have been positively diagnosed.

Bacteremia↗
PubMed1994

[Sepsis caused by non-O1-Vibrio cholerae: a patient in The Netherlands].

In a 84-year-old woman extraintestinal infection by non-OI Vibrio cholerae was diagnosed. She had septicaemia with cholangitis and cholecysto- and choledocholithiasis. Until now 26 patients with non-OI V. cholerae septicaemia have been reported. Most had an underlying disease, usually a chronic liver disease or haematological malignancy. These disorders were not present in our patient. She was treated with co-trimoxazole and afterwards she underwent a cholecystectomy and common bile duct exploration. At the time of operation no non-OI V. cholerae could be isolated from the gallbladder or the bile from the common bile duct. A possible cause of the infection was a herring which the patient had eaten six weeks before hospital admission.

Aged↗
PubMed1994

Native-valve endocarditis due to CDC coryneform group ANF-3: report of a case and review of corynebacterial endocarditis.

Endocarditis due to a bacterium of CDC coryneform group ANF-3 developed in the native aortic valve of a patient without predisposing factors other than valvular calcification. A review of the literature indicates that corynebacteria are an increasingly important cause of endocarditis. Problems in identification and treatment remain. Techniques for the culture and quick identification of these organisms and effective regimens for treatment of the infections they cause are needed.

Actinomycetales↗
PubMed1994

Typhoid fever: a review of its impact and diagnostic problems.

A retrospective analysis was done on the diagnosis of typhoid fever based on clinical symptoms and available laboratory data over the last 16 years from rural areas of four African countries. This analysis concentrated on the reliability of diagnosis without cultures which cannot be performed in most rural hospitals due to lack of the necessary expertise and equipment. The analysis showed the problem to be increasing perhaps because of interaction of salmonella infection with human immunodeficiency virus (HIV), malnutrition and other infections together with neglected sanitary facilities and lack of clean water. The use of certain cardinal clinical symptoms combined with available laboratory tests were shown to enhance the diagnosis of typhoid fever, especially in vulnerable persons. In conclusion the paper suggests that using the approach followed to obtain this data in rural tropical areas one can confidently make a diagnosis of typhoid fever.

Adult↗
PubMed1994

Sensitivity and negative predictive value of swab cultures in musculoskeletal allograft procurement.

Seventy-five fibular specimens were obtained from postmortem donors using aseptic surgical techniques. All specimens were swabbed following the same technique as routinely used for retrieved musculoskeletal grafts. After swabbing, the specimens were placed in BHI-culture medium. Three different protocols were subsequently followed: (1) culture of the entire bone specimen in BHI-culture medium, (2) culture of the swab incubated on blood agar and chocolate plates, and (3) culture of the swab in BHI-culture medium. A control group included 20 sterilized bone specimens that were cultured entirely in BHI-culture medium according to Protocol 1. The sensitivity and negative predictive value were found to be 10% and 9% in Protocol 2 and 13% in Protocol 3. These findings imply that swab cultures are inadequate to detect bacterial contamination of musculoskeletal allografts in all cases. However, the instances of infection after transplantation of allografts bacteriologically screened according to Protocols 1 and 2 do not exceed those reported in other similar series. This suggests an acceptable bioburden.

Bacteria↗
PubMed1993

In vitro study on the integrity of a hydroxylapatite coating when challenged with staphylococci.

An in vitro study was performed to evaluate the effect of Staphylococcus aureus and Staphylococcus epidermidis on the integrity of a hydroxylapatite coating. The coating plasma-sprayed on poly(L-lactide), showed dissolution during a 24 h incubation period. This was indicated by an increase in pH and calcium release in the buffer solution. After 4 h of incubation, calcium levels decreased due to the precipitation of calcium phosphate complexes on the coating. The bacteria digested or dissolved the coating, creating irregularly shaped holes. Although the integrity of the hydroxylapatite coating was focally damaged within 2-4 h of incubation with staphylococci, the extent of the damage was only marginal. Due to the formation of a layer of CaP precipitates though, bacteria could not be counted accurately after 4-8 h of incubation. This model could reveal part of the failure mechanism of infected hydroxylapatite coated implants.

Calcium↗
PubMed1993

Adherence to a metal, polymer and composite by Staphylococcus aureus and Staphylococcus epidermidis.

Bacterial adherence on to several materials with a potential application in reconstructive surgery was studied. Polymer (poly(L-lactide)), composite (hydroxyapatite/poly(L-lactide)) and metal (316L stainless steel) were evaluated both as smooth and sandblasted specimens. All materials were incubated in phosphate-buffered saline, challenged with Staphylococcus aureus or S. epidermidis and evaluated for up to 24 h. S. aureus showed a preference for the metal and composite tested over the polymer used. For S. epidermidis no preference was found for one of the investigated materials. The influence of surface roughness on bacterial growth was demonstrated by increased colonization on the sandblasted specimens.

Bacterial Adhesion↗
PubMed1993

Cytotoxic effects of topical antimicrobial and antiseptic agents on human keratinocytes in vitro.

The cytotoxicity of commonly used antimicrobial and antiseptic agents to cultured human keratinocytes was investigated, combining a morphologic assay with a quantitative neutral red (NR) spectrophotometric assay. Main outcome criteria of response were the initial cytotoxicity (NR 90) and midpoint cytotoxicity (NR 50) and the highest tolerated dose (HTD), a concentration causing the first observed morphologic alterations. These values were compared with commonly administered clinical doses or calculated doses. Thirty-five agents were evaluated; five agents were also subjected to an assay for cell morphologic alterations, and HTD and percentage of cells taking up trypan blue and annihilation dose were assessed. These studies show that in clinical concentrations many, but not all, agents exert profound cytotoxic effects. The results suggest that under certain conditions cultured epithelial grafts may be exposed to clinical concentrations of neomycin, clindamycin, framycetin, erythromycin, gentamicin, and 0.1% solutions of povidone-iodine. Tetrachlorodecaoxygen anion complex (TCDO) should be further evaluated as a likely effective cleansing agent before culture grafting.

Anti-Bacterial Agents↗