[Antibiotic sensitivity test. Comparative multicenter study of the gel diffusion and ATB methods]

The ATB method is a new method for antibiotic susceptibility testing. In a collaborative study, it was compared to a standard disc diffusion method. 23 strains were tested to determine reproducibility and 969 strains were used in the comparative study. Reproducibility of both methods is equivalent; differences due to strains were observed. Agreement between both methods is 87,9%, minor discrepancies are 8,7% and major discrepancies are 3,3%. Significant differences were found for carbenicillin and cefalotin and confirmed by MIC determination using the agar dilution method. Overall results show that the ATB method is reliable and comparable to disc diffusion for routine susceptibility testing.

[Enterobacter cloacae. In vivo emergence of a variant resistant to new beta-lactams during treatment with lamoxactam-gentamicin]

In a patient recently operated for an abdominal gun wound, and given gentamicin-cephalosporin (cefoxitin for one day, then moxalactam) for 11 days, treatment failed as a result of emergence of a E. cloacae variant resistant to beta-lactams only, i.e. carbenicillin, mezlocillin, cefamandole (CFM), cefoperazone (CPZ), cefotaxim (CTX) and moxalactam ( MOX ). The initial susceptible strains isolated from blood cultures (SH1, SH2) and the resistant ones isolated 11 days later from pancreatic pus (RP) and blood cultures ( RH1 , RH2 ) shared the same chemotype. MICs of CFM, CPZ, CTX, and MOX were much higher (1 000 to 4 000 fold) for RH1 than for SH1. The biochemical mechanism of resistance showed the six following features: loss of antimicrobial activity of CFM, CTX and MOX added to RH1 cultures; much higher (1 500 fold) beta-lactamase activity for RH1 than for SH1 (iodometric and microacidimetric methods); beta-lactamases focusing at the same pl (greater than 8) produced by RH1 , RP and also, but only after induction, SH1 and SH2; cephalosporinase-type beta-lactamase according to the enzymatic activity profile; restoration of RH1 's susceptibility to CFM, CTX and MOX merely by adding cloxacillin; apparently unchanged crypticity for RH1 . The enzymatic mechanism (cephalosporinase hyperproducing variant) seems very likely.

[Beta-lactamases of ampicillin-resistant Salmonella]

One hundred and five strains of Salmonella, including 103 clinical isolates, were examined for resistance to beta-lactams (ampicillin, carbenicillin). The resistance frequency was 5.9 and 40.6%, respectively, according to the geographical source: France or Senegal. The mechanism of resistance to beta-lactam antibiotics was always related to the biosynthesis of one constitutive beta-lactamase (beta la+). By analytical isoelectric focusing on gel of all crude sonic extracts, four types of enzymes were identified: TEM-1, TEM-2, OXA-1 and SHV -1. TEM-1, the most prevalent, was observed among 17 serotypes, TEM-2 among 3 including S. poona , and OXA-1 among 2 serotypes. SHV -1 was detected in all isolates of S. ordonez (38) but only among strains of this serotype. Among others factors involved in their distribution, differences were reported according to the geographical origin of the studied strains. In France, the three types, TEM-1, TEM-2 and OXA-1, were isolated only in the north. Moreover, the resistance frequency was 4-fold higher (7.3%) than in the south (1.8%). In Africa (Senegal), three types were individualized: TEM-1, TEM-2 and SHV -1. The SHV -1 type was only detected in clinical isolates of S. ordonez from Senegal, all of which were multi-resistant to other antibiotics (chloramphenicol, sulfonamides and tetracyclines).

Tinnitus asymmetry

In the present study, the relationship between the location of tinnitus and the location of the greater hearing impairment was investigated. 62 subjects suffering from tinnitus underwent audiometric testing and were required to identify the location of their tinnitus. All of the subjects had a history of exposure to loud noise. The results of the study showed an asymmetric relationship between the variables examined. Most of the subjects with a greater hearing loss on the right side reported right-sided tinnitus, while the majority of subjects with a greater loss in the left ear reported tinnitus heard identically in both ears or tinnitus heard louder on the right side. An assumption was made that this phenomenon is related to differential hemispheric responsiveness to abnormal neural activity arising in the peripheral parts of the auditory system as a result of cochlear damage, activity which is the presumed origin of neurogenic tinnitus.

Nosocomial infections by chlorhexidine solution contaminated with Pseudomonas pickettii (Biovar VA-I)

Over a period of 10 days, six patients in a cardiac intensive care unit developed Pseudomonas pickettii (biovar VA-I) septicaemia after installation of a venous catheter. The organism was also recovered from all the vials of the aqueous solution of 0.05 per cent chlorhexidine ('Hibitane') prepared with contaminated bidistilled water. There were no further cases of infection when the use of this water was prohibited.

Tinnitus pitch and acoustic trauma

56 Subjects complaining of tinnitus underwent an audiometric test and a test for identifying the analogous pitch of their tinnitus. All of the subjects reported that they had been exposed to noise in the past. The subjects were divided into two groups on the basis of their audiometric test results. Group P was composed of subjects who showed a sensorineural hearing loss typical of acoustic trauma. Group N was composed of subjects whose hearing was within normal limits. The pitch of the tinnitus in group P was concentrated in the high-frequency range, whereas in group N tinnitus pitch values were distributed over the low and mid-audiometric frequency spectrum. It was deduced that different processes are involved in the generation of tinnitus in the two groups.

[Rapid determination of the synergy of clavulanic acid and beta lactams by measuring the intracellular ATP by bioluminescence]

Twenty clinical isolates of ampicillin- and carbenicillin-resistant or susceptible (two strains) Gram-negative rods, producing at least one beta-lactamase, were examined for susceptibility to a combination of ampicillin or carbenicillin with clavulanic acid (enzymatic inhibitor). Synergy was evaluated by the reduction of the beta-lactam agar dilution MIC and by the measurement of intracellular AYP using firefly bioluminescence. The potentiation effect of clavulanic acid was variable, depending on resistance levels, species and types of beta-lactamase (TEM, SHV-1, CARB, OXA, MAL and Cpase). The synergy was significant, with 10 mg/l of inhibitor for all the strains producing TEM-1, TEM-2 and Carb-2 except for one strain of Serratia marcescens (TEM-2). The synergy was weak for Levinea strains (Citrobacter diversus biotype b), biosynthesizing specific penicillinases as MAL-1. No potentiation effect was observed for strains producing a cephalosporinase, such as Escherichia coli and Pseudomonas aeruginosa. This effect appeared to be variable for strains producing the oxacillin-hydrolysing enzyme (OXA-1), such as E. coli and P. aeruginosa. A positive correlation was clearly demonstrated between the MIC values and the intracellular ATP concentration in bacteria within 2 h. The opportunity of using the firefly assay for the rapid determination of synergy between beta-lactam antibiotics and clavulanic acid is discussed.

Paternity testing: analysis of six blood groups and HLA markers, with particular reference to comparison of races

Blood groups (ABO, Rh, MNSs, Kell, Duffy, and Kidd) and HLA markers were tested in cases involving 563 children of disputed parentage. In 149 (26.5%) cases, the accused men were excluded as the biologic fathers of the children in question. One hundred forty of the 149 exclusions were direct exclusions. Five exclusions were based on red blood cell data alone, i.e., HLA was non-exclusionary. Of the remaining 414 cases in which the alleged father could not be excluded as the biologic father, in 361 (87.2%) instances, the plausibility of paternity ws 95% or greater, and in 385 (93.0%) instances the comparison of men value was 20 or greater. Caucasians, blacks, and men of other races were involved in 367 (65.1%), 185 (33%), and 11 (1.9%) cases, respectively. No significant difference among races was observed in the rate of exclusion of accused men. However, of the non-excluded men, in a significantly greater proportion of black men than white men, the plausibility of paternity was below 95%. The difference was probably due to lower polymorphism of the markers tested in blacks than in whites. It is suggested that tests for additional polymorphic genes be directed towards the 12-15% of the nonexclusionary cases with plausibility of paternity values below 95%.

[Rapid bioassay of gentamicin by bioluminescence (author's transl)]

Assay of bacterial intracellular ATP levels using the firefly bioluminescence system allows a very sensitive monitoring of bacterial growth. This test has been used in some laboratories fro performing a rapid microbiological assay of the concentration of antibiotics in the serum of treated patients. Rapidity of antibiotic determination is especially important in the case of antibiotics for which therapeutic concentration are close to toxic concentration. In the present work we have used the bacterial strain Klebsiella edwardsii var. atlantae for a rapid assay of gentamicin in the serum. We show that this assay is very accurate in the range of therapeutic serum concentrations. It may be readily performed in a routine laboratory with commercially available ATP extractors and luciferine-luciferose mixtures. This assay has been shown to correlate optimally with the classical plate diffusion assay (r = 0,983) and to be independent of the presence of beta-lactams in the serum.

Lactose tolerance in lambs with rotavirus diarrhoea

It has been suggested that lactose malabsorption is an important factor in producing the diarrhoea of acute rotavirus infection. Accordingly, the lactose tolerance of gnotobiotic newborn lambs, infected with lamb rotavirus, has been investigated by clinical studies and tissue enzyme assays. Although lactase activity is low in affected areas of the small intestine, rotavirus infected lambs are not lactose intolerant as assessed by the measurement of reducing substances in the faeces, or by the clinical effects and blood glucose levels after a 5.8 mmol (2 g)/kg lactose load on the second day post-infection. Lactose intolerance could be demonstrated by using extremely high (29.2 mmol (10 g)/kg) doses of lactose, three or four times the normal dietary lactose intake. These experiments suggest that lactose-containing feeds (such as maternal milk) are not necessarily contraindicated in patients or animals with rotavirus diarrhoea.

[Bacteroides fragilis. Maternal-placental and foetal contamination (author's transl)]

In order to study the maternal-placental and foetal contamination, cytologic study and aerobic-anaerobic cultures were performed on 1 000 placentae of infants who were referred to the Intensive Care Unit. Bacteroides were isolated from 30 specimens, and on smears, Gram negative bacteria were found on 11 of these cases. Only in 2 infants Bacteroides were isolated from blood, gastric aspirate and meconium; 20 infants were said to be infected on clinical and biological bases; eight were normal. Bacteroides infection is usually benign; the symptoms are not specific; the diagnosis is often delayed and the treatment uneasy. Nowadays, Carbenicillin, Ticarcilin, Cefoxin or Metronidazole are advised, according to the sensibility of the organism.

[Clostridium perfringens infection and necrotising enterocolitis]

During a four year period (1974--1977) 21 infants died as a result of severe necrotising enterocolitis (N.E.C.). In 9 cases, Clostridium perfringens was isolated. When this organism is recovered either from the placenta or from the first meconium and or when the signs of the disease appear within a few days of birth, materno-fetal transmission of the infection may be suspected. The infection occurs most frequently in neonates in whom the gastrointestinal tract was already colonized by Clostridium.

[Hepato-pulmonary Nocardia infections (report of one case) (author's transl)]

Actinomycosis due to Nocardia asteroides is a mainly pulmonary disease; the metastases are due to migration of the germ in the blood from the primary lung focus. The case reported here concerned a patient whose initial symptoms were mainly hepatic, suggesting an amoebic abscess of the liver. The pulmonary lesions appeared only secondarily with presence in the sputum of the nocardia which was responsible. Prolonged treatment with trimethoprime sulfamethazole led to complete and lasting cure of the lesions, confirmed radiographically and by a liver scan.

Hypothalamic-pituitary-gonadal dysfunction in men using cimetidine

We studied the effect of cimetidine therapy (1200 mg per day by mouth for nine weeks) on the hypothalamic-pituitary-gonadal axis of seven men. There was a 43 per cent mean reduction in sperm count after therapy. The luteinizing hormone response to luteinizing hormone releasing factor was also reduced, and a statistically significnat rise in plasma testosterone occurred, although it was less than that before therapy. Gonadotropin responses to provocative clomiphene stimulation were inadequate when compared with those of controls. Cimetidine did not affect the responses of thyroid-stimulating hormone, prolactin, growth hormone and thyroxine to thyrotropin releasing factor. Caution is advisable in administration of cimetidine for prolonged periods to young men.

Pathogenesis of diarrhoea caused by astrovirus infections in lambs

Experimental infection of 2-day-old gnotobiotic lambs with lamb astrovirus produced mild diarrhoea after an incubation period of about 48 hours. No other clinical symptoms developed. Infection was studied by immunofluorescent and histological examination of tissues from the lambs. Astroviruses infected only mature villus epithelial cells and subepithelial macrophages in the small intestine, where they produced partial villus atrophy. Infected enterocytes were replaced with cuboidal cells from the crypts, and the lesion gradually healed by 5 days after infection. No serological relationship was detected by immunofluorescence between lamb astrovirus antigen in gut sections and antisera to either calf or human astrovirus.

[Severe complications following intermittent administration of rifampicin]

In the last two years the authors have noted the cases of five patients with pulmonary tuberculosis to which intermittent treatment with Rifampicin was administered (twice weekly, 600-900 mg/day), in association with Ethambutol. Between 2 and 6 months after the treatment was started, 24-72 hours after the last administration of Rifampicin acute renal failure developed in all five cases. Two of the patients also had signs of liver failure (increased serum transaminase, lowered pseudo-cholinesterase, increased BSP retention), and in one of them there was also a hematological syndrome consisting in hemolytic anemia and thrombocytopenia. Four of the patients benefited from application of diuretics, hydroelectrolytic re-equilibration and/or hemodialysis. One of the subjects died 12 hours after being hospitalized, with acute pulmonary oedema, refractory to treatment. From the histopathological viewpoint glomerular lesions were found in the kidney (non-uniform thickening of the basal membranes by PAS-positive deposits). In two of the patients various immunological tests have been carried out (Coombs test, lymphocyte-migration inhibition, serum and urine immunelectrophoresis) that, by their alterations, provide some elements indicating the immunological origin of the phenomena.

[Distinction between beta-lactamases of immunotypes 1 or 2 using a new beta-lactam antbiotic (author's transl)]

The resistance of Gram negative bacteria to ampicillin and carbenicillin is often associated with the presence of plasmidic transferable beta-lactamase (class III of Richmond and Sykes). Using immunological and physico-chemical tests, two sub-classes have been identified. The sensitivity of Escherichia coli K12 with plasmid P111 (immunotype 1) or plasmid P453 (immunotype 2) determined by means of the minimal inhibitory concentrations, contrasts significantly with a new beta-lactam antibiotic, X-587. Study of the kinetic constants (Km, Vmax) of the beta-lactamases confirms and explains this difference. Thus we have a simple and rapid method for differentiation of these 2 types of enzymes.