Comparison of contamination of femoral heads and pre-processed bone chips during hip revision arthroplasty.

With bone impaction grafting, cancellous bone chips made from allograft femoral heads are impacted in a bone defect, which introduces an additional source of infection. The potential benefit of the use of pre-processed bone chips was investigated by comparing the bacterial contamination of bone chips prepared intraoperatively with the bacterial contamination of pre-processed bone chips at different stages in the surgical procedure. To investigate baseline contamination of the bone grafts, specimens were collected during 88 procedures before actual use or preparation of the bone chips: in 44 procedures intraoperatively prepared chips were used (Group A) and in the other 44 procedures pre-processed bone chips were used (Group B). In 64 of these procedures (32 using locally prepared bone chips and 32 using pre-processed bone chips) specimens were also collected later in the procedure to investigate contamination after use and preparation of the bone chips. In total, 8 procedures had one or more positive specimen(s) (12.5 %). Contamination rates were not significantly different between bone chips prepared at the operating theatre and pre-processed bone chips. In conclusion, there was no difference in bacterial contamination between bone chips prepared from whole femoral heads in the operating room and pre-processed bone chips, and therefore, both types of bone allografts are comparable with respect to risk of infection.

Device-independent, real-time identification of bacterial pathogens with a metal oxide-based olfactory sensor.

A novel olfactory method for bacterial species identification using an electronic nose device called the MonoNose was developed. Differential speciation of micro-organisms present in primary cultures of clinical samples could be performed by real-time identification of volatile organic compounds (VOCs) produced during microbial replication. Kinetic measurements show that the dynamic changes in headspace gas composition are orders of magnitude larger than the static differences at the end of fermentation. Eleven different, clinically relevant bacterial species were included in this study. For each of the species, two to eight different strains were used to take intra-species biodiversity into account. A total of 52 different strains were measured in an incubator at 37 degrees C. The results show that the diagnostic specificities varied from 100% for Clostridium difficile to 67% for Enterobacter cloacae with an overall average of 87%. Pathogen identification with a MonoNose can be achieved within 6-8 h of inoculation of the culture broths. The diagnostic specificity can be improved by broth modification to improve the VOC production of the pathogens involved.

Rapid identification of mycobacteria by Raman spectroscopy.

A number of rapid identification methods have been developed to improve the accuracy for diagnosis of tuberculosis and to speed up the presumptive identification of Mycobacterium species. Most of these methods have been validated for a limited group of microorganisms only. Here, Raman spectroscopy was compared to 16S rRNA sequencing for the identification of Mycobacterium tuberculosis complex strains and the most frequently found strains of nontuberculous mycobacteria (NTM). A total of 63 strains, belonging to eight distinct species, were analyzed. The sensitivity of Raman spectroscopy for the identification of Mycobacterium species was 95.2%. All M. tuberculosis strains were correctly identified (7 of 7; 100%), as were 54 of 57 NTM strains (94%). The differentiation between M. tuberculosis and NTM was invariably correct for all strains. Moreover, the reproducibility of Raman spectroscopy was evaluated for killed mycobacteria (by heat and formalin) versus viable mycobacteria. The spectra of the heat-inactivated bacteria showed minimal differences compared to the spectra of viable mycobacteria. Therefore, the identification of mycobacteria appears possible without biosafety level 3 precautions. Raman spectroscopy provides a novel answer to the need for rapid species identification of cultured mycobacteria in a clinical diagnostic setting.

Polymorphism in CC-chemokine ligand 2 associated with tuberculosis in Zambia.

Polymorphism in various genes that may influence susceptibility to tuberculosis (TB) was examined in 46 TB patients and 119 healthy tuberculin-positive controls in Zambia. The odds of having TB was 2.8-fold higher in carriers of the -2518 AG single-nucleotide polymorphism in the promoter region of the CC-chemokine ligand 2 than in those carrying the homozygous genotype AA (95%CI 1.3-5.5).

[A patient with fever following a visit to the tropics: tick-borne relapsing fever discovered in a thick blood smear preparation]. / Een patiënt met koorts na een bezoek aan de tropen: 'tick-borne relapsing fever' ontdekt in een dikkedruppelpreparaat.

A 26-year-old woman presented with a 2-day history of fever peaking to 39 degrees C and cold shivers that developed after a 2-weeks trip to Guatemala and Belize. Prior to the fever the patient had felt symptoms of a common cold and general malaise. Moreover, she complained of generalised myalgia and nausea. She had taken paludrine as a prophylactic against malaria. Borrelia spirochaetes, the pathogen of relapsing fever, were detected in a thick blood smear preparation. On the basis of the anamnesis, geography and specific exposure, the patient had a form of relapsing fever that is transmitted by ticks and not by lice: tick-borne relapsing fever. She was treated with doxycycline, 100 mg b.i.d. for 7 days. She could be discharged home in good condition after 2 days.

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.

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.

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.

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.

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.

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.

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.

Bacteriology of infections in a rural tropical area of Kenya: isolates and antibiotic susceptibility.

No microbial data are available for rural tropical areas. Yet most people in Africa live in rural areas where the burdens of infectious diseases remain the primary cause for morbidity and mortality. A pilot study was done by culturing midstream urine from patient with dysuria (100 with Gram-negative fermentative rods), blood from patients with FUO (55/307 positive) and swabs from patients with infected wounds (29 with Staphylococcus aureus). Bacteria were identified and susceptibility tests were performed according to protocols. Klebsiella was the most common isolate from urine (48%). The overall resistance in urine isolates for ampicillin was 76% and for cotrimoxazole, 60%. The main isolates from blood were Klebsiella Enterobacter sp (21/55) and Salmonella (14/55) in patients from agricultural areas, and Staphylococcus aureus (12/55) in patients from desert areas. The Staphylococcus aureus from wounds were all penicillin resistant and 9/29 were cloxacillin resistant. Influence of the environment, underlying pathology and previous use of antibiotics give unexpected predominance of Klebsiella and high resistance in all isolates. Large scale surveillance studies are needed so that prescription of antibiotics can be based on locally obtained data.

Prevalence of resistance of N. gonorrhoeae to penicillin and three other antibiotics in a rural area in Kenya.

Of 90 isolates of Neisseria gonorrhoeae in a rural area in Kenya, 44 (48.9%) produced beta-lactamase (penicillinase). Testing for susceptibility of 35 penicillinase producing N. gonorrhoeae (PPNG) strains to four antibiotics yielded the following results: 16 (45.7%) showed a decreased susceptibility to tetracycline; six (17.1%) showed resistance, probably plasmid mediated; 10 (28.6%) had intermediate susceptibility to gentamicin; one (2.9%) was resistant; and two (5.7%) isolates were resistant to cefotaxime. 16 (57.1%) of 28 non PPNG strains showed a decreased susceptibility to penicillin; 10 (35.7%) were resistant. Nine (32.1%) of 28 non-PPNG isolates showed intermediate susceptibility to tetracycline; one (3.6%) was resistant. Eight of non PPNG isolates (28.6%) showed decreased susceptibility to gentamicin. These results imply that penicillin and tetracycline should be abandoned as primary therapy. For the time being, thiamphenicol and spectinomycin seem to be good alternatives. The observation of cefotaxime resistance in N. gonorrhoeae in a rural area implies a warning concerning future possibilities for use of third generation cephalosporins.

[An unusual hospital infection: Aeromonas hydrophila infection due to the use of leeches]. / Een ongewone ziekenhuis-infectie: Aeromonas hydrophila-infectie bij gebruik van bloedzuigers.

A patient is described with an infection with Aeromonas hydrophila after the use of medical leeches to improve the circulation of a congested region of surgery. The use of medical leeches and the treatment of a leech-related infection are discussed.

[Community-acquired pneumonia: pathogens and course in patients admitted to a general hospital]. / Buiten het ziekenhuis opgelopen pneumonie: verwekkers en beloop bij patiënten opgenomen in een algemeen ziekenhuis.

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.

[Sepsis caused by non-O1-Vibrio cholerae: a patient in The Netherlands]. / Sepsis door non-O1-Vibrio cholerae: een patiënt in Nederland.

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.

Isolation of non-tuberculous mycobacteria at three rural settings in Zambia; a pilot study.

To assess the role of non-tuberculous mycobacteria (NTM) as a cause of tuberculosis-like diseases in Zambia, 167 chronically ill patients, hospitalized in three rural hospitals in Katete, Sesheke and Chilonga, were examined by microscopy and liquid culture for the presence of NTM. The percentages of patients with a positive culture for Mycobacterium tuberculosis complex were similar in the three geographical locations (19-25%). In contrast, the percentage of NTM ranged from 78% in Katete and 65% in Sesheke to 21% in Chilonga. Furthermore, the distribution of NTM species was different at the three geographical sites. In seven patients, true NTM-associated disease was suspected: five with Mycobacterium lentiflavum and two with Mycobacterium intracellulare. Analysis of possible risk factors indicated that the OR for NTM culture-positive sputum was significantly higher for patients living in Katete and Sesheke. Female gender and chest X-ray appearances of tuberculosis were independently associated with NTM culture-positive sputum. NTM colonization and disease in hospitalized, chronically ill patients in rural Zambia appear to be common.