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A survey of antimicrobial resistance in Streptococcus pyogenes, performed within the framework of a national surveillance program, has revealed a dramatic increase in resistance of S. pyogenes to erythromycin in most areas of Italy. In virtually all the centers that provided data for 3 consecutive years, the incidence of erythromycin-resistant strains increased twofold to 20-fold from 1993 to 1995 and was greater than 30% in five of the 14 centers participating in the study. The clonality of erythromycin-resistant isolates was studied in 15 strains isolated from different patients at the Institute of Microbiology of Verona University (Verona). The features of the Verona isolates and the substantially different rates of erythromycin and clindamycin resistance observed in most centers suggest that the spread of different resistance genes in multiple clones might be occurring throughout the country.

Previous studies suggested that circulating tumor necrosis factor alpha (TNF-alpha) may have a pathophysiologic role in experimental neonatal sepsis induced by group B streptococci (GBS). This study was undertaken to investigate the ability of the type III and group-specific polysaccharides of GBS to induce TNF-alpha production and TNF-alpha-dependent lethality in neonatal rats. The cytokine was detected in plasma samples by the L929 cytotoxicity assay. Intracardiac injections of either polysaccharide induced dose-dependent, transient elevations in plasma TNF-alpha levels that returned to baseline values after 5 h. The group-specific antigen induced significantly higher mean peak TNF-alpha levels than the type III antigen (125 +/- 47 versus 44 +/- 15 U/ml with 70 mg/kg of body weight). Glycogen (70 mg/kg), used as a negative control, did not induce TNF-alpha. The lipopolysaccharide-neutralizing agent polymyxin B did not decrease TNF-alpha levels induced by either polysaccharide, ruling out contamination with endotoxin as a possible cause of TNF-alpha induction. Fifty percent lethal doses of the type III and group-specific antigens given as intracardiac injections were 105 and 16 mg/kg, respectively. Salmonella endotoxin, used as a positive control, had a 50% lethal dose of 0.1 mg/kg. The lethal activities of GBS polysaccharides, as well as endotoxin, were completely prevented by pretreatment of neonatal rats with the respective specific antibodies or anti-murine TNF-alpha serum. To assess the relative importance of the type-specific substance in TNF-alpha induction by whole bacteria, two unrelated GBS transposon mutants devoid of only the type-specific capsular polysaccharide (COH1-13 and COH31-15) were employed. Each of the heat-killed unencapsulated mutants was able to produce plasma TNF-alpha level elevations or TNF-alpha-dependent lethality but was significantly less efficient in these activities than the corresponding encapsulated wild-type strain. These data suggest that the presence of type-specific material on GBS is not necessary for the stimulation of TNF-alpha production. Type III capsular polysaccharide, however, can significantly increase the ability of GBS to induce TNF-alpha. Further studies will be needed to assess the importance of TNF-alpha induction by the group- and type-specific antigens in the pathophysiology of GBS disease.

This paper is focused on the jointly use of satellite Quickbird (QB) images and Ground Probing Radar (GPR) for assessing their capability in the detection of archaeological adobe structures (sun-dried earth material). Such detection is particularly complex. due to the low contrast generally existing between the archaeological features and the background. Two significant test areas were investigated in the Ceremonial Centre of Cahuachi (in the Nasca territory, Southern Peru) dating back to 6th century BC to 4th century AD. Our results showed that both satellite and GPR data provided valuable indications for unearthing precious ancient remains. Our preliminary analyses pointed out that the integrated use of non destructive remote sensing techniques has high potentiality for its important scientific implications and for its significant contributions to cultural resource management.

AOVV Azienda Ospedaliera Valtellina e Valchiavenna Presidio di Sondalo, Via Zubiani 33, 23039 Sondalo, 2 Sez. Microbiologia, Dip. SMEC, Universita di Pavia, Via Brambilla 74, 27100 Pavia La.M.M.B., Dip. Biologia Molecolare, Universita di Siena, Policlinico Le Scotte, Via Bracci, 53100 Siena Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Roma, O.B.L., Universita di Cagliari, Via Binaghi 4, 09121 Cagliari.

Type-specific antibodies against M protein are critical for human protection as they enhance phagocytosis and are protective. An ideal vaccine for the protection against Streptococcus pyogenes would warrant mucosal immunity, but mucosally administered M-protein has been shown to be poorly immunogenic in animals. We used a recombinant M type 6 protein to immunize mice in the presence of synthetic oligodeoxynucleotides containing CpG motifs (immunostimulatory sequences: ISS) or cholera toxin (CT) to explore its possible usage in a mucosal vaccine.Mice were immunized by intranasal (in) or intradermal (id) administration with four doses at weekly intervals of M6-protein (10 microg/mouse) with or without adjuvant (ISS, 10 microg/mouse or CT, 0,5 microg/mouse). M6 specific antibodies were measured by enzyme linked immunosorbent assay using class and subclass specific monoclonal antibodies.The use of ISS induced an impressive anti M-protein serum IgG response but when id administered was not detectable in the absence of adjuvant. When used in, M-protein in the presence of both ISS and CT induced anti M-protein IgA in the bronchoalveolar lavage, as well as specific IgG in the serum. IgG were able to react with serotype M6 strains of S. pyogenes. The level of antibodies obtained by immunizing mice in with M-protein and CT was higher in comparison to M-protein and ISS. The analysis of anti-M protein specific IgG subclasses showed high levels of IgG1, IgG2a and IgG2b, and low levels of IgG3 when ISS were used as adjuvant. Thus, in the presence of ISS, the ratio IgG2a/IgG1 and (IgG2a+IgG3)/IgG11 indicated a type 1-like response obtained both in mucosally or systemically vaccinated mice.Our study offers a reproducible model of anti-M protein vaccination that could be applied to test new antigenic formulations to induce an anti-group A Streptococcus (GAS) vaccination suitable for protection against the different diseases caused by this bacterium.

A possible relationship has been suggested between tic disorders and streptococcal infections. To understand the complex relationship between streptococcal infections and neuropsychiatric disorders in children the present study was done on colour Doppler echocardiography of patients with possible post-streptococcal tic disorders.The patients were 23 children (22 males, 1 female) affected by tic disorders, who at the time of the observation presented (or had presented in the past) signs of streptococcal infections temporally related to the onset or recrudescence of tic disorders. Echocardiographic examination and laboratory tests were performed on these children.In 4 cases a mild mitral insufficiency and in 8 cases a minimal mitral insufficiency was seen, all haemodynamically not significant. Follow up studies (up to 1 yr) showed the consistency and persistence of these findings. Of the 12 patients with echocardiographic abnormalities, 10 displayed very high anti streptolysin O (ASO) titres, 5 showed positive cultures for GAS and 9 had abnormal ESR, even if no significant differences were found in respect to patients with tics and normal echocardiography.With the caution due to the design of study and to low number of patients, our data seem to indicate that the pathophysiology of GAS-infection related tic disorders is similar to that SC, at least in some cases.

An association between the onset or recrudescence of some neuropsychiatric disorders in children such as tic disorders and group A streptococcal (GAS) infections has been suggested. No information is available on the characterization of GAS strains associated with such disorders. The present study was undertaken to characterize the GAS strains isolated from children with tic disorders and to determine and correlate the antistreptolysin O (ASO) titre with the presence of GAS.During 1996-2001, 368 children with tic disorders were investigated for possible exposition to streptococcal antigens. All children, at the time of the first visit and during the follow up visits were apparently healthy and showed no clinical evidence of streptococcal infections or post streptococcal sequelae. Blood and throat swab samples were collected and serological and bacteriological tests done. The isolates obtained were investigated for T pattern, M protein and emm type, as well as for the production of protease.Of the 800 throat swabs studied 100, corresponding to 67 patients, were positive for GAS; 49 children were found positive for GAS only once during the study, 18 had more than one sample positive for different serotypes, 8 were positive twice or more for the same type. ASO titres of these children were, in general, elevated. Five types, namely type M12, 3, 13, 11, 1, accounted for 39 per cent of the isolates, M12 being the most common, but a large number of different types were also found. A large number of isolates (62%) showed an elevated prodution of protease in the casein plate assay.Despite the high level of ASO titres found, the results were not in favour of a particular virulence or invasivity of the isolates. Only a few colonies per sample were found indicating that factors different from the microbial virulence play a role in this type of disease.

To determine the prevalence of resistance to the main anti-tuberculosis drugs in newly and previously treated tuberculosis patients in Italy and to evaluate the contribution of foreign-born and human immunodeficiency virus (HIV) positive cases to drug resistance.Methods and definitions were derived from the WHO/IUATLD Global Project on Anti-tuberculosis Drug Resistance Surveillance. Univariate and multivariate analysis was used to study prevalence rates of drug resistance in risk groups.In a national survey in Italy, 810 initial isolates of Mycobacterium tuberculosis (683 from new cases, 115 from retreatment cases and 12 from patients whose treatment history was unknown/dubious) were analysed. Low prevalence of drug and multidrug resistance was found in the new cases (isoniazid 2.9%; rifampicin 0.8%; multidrug resistance 1.2%; any drug resistance 12.3%). The prevalence of resistance to isoniazid and rifampicin was significantly higher in immigrants and HIV-positive subjects, respectively. A high prevalence of drug resistance was found in cases with previous treatment failure or default (isoniazid 5.2%; rifampicin 4.3%; multidrug resistance 36.5%; any drug resistance 61.7%).Special efforts are necessary to monitor trends in drug resistance and to ensure favourable treatment outcomes among immigrants and HIV-positive tuberculosis cases.

To assess the effect of interferon-gamma (IFNgamma) administration on the evolution of systemic infection and septic arthritis induced by group B streptococci (GBS) in mice.CD1 mice were inoculated intravenously with arthritogenic strain 1/82 of type IV GBS. Exogenous murine IFNgamma or anti-IFNgamma monoclonal antibodies were administered intravenously either 2 hours (-2 hours) before or 18 hours after infection with 1 x 10(7) GBS. Mice were monitored daily for survival and for signs of arthritis. In a subsequent set of experiments, mice were killed at selected times for examination of bacterial clearance, joint histopathology, and cytokine production.Mortality in mice treated with IFNgamma at -2 hours was 100%, compared with 20% in those treated at 18 hours and with 40% in controls. As indicated by the arthritis score, mice treated with IFNgamma at -2 hours developed early and more severe arthritis, whereas those treated at 18 hours had milder arthritis compared with infected controls. Less severe joint pathology in the mice treated with IFNgamma at 18 hours correlated with low levels of interleukin-6 (IL-6) and IL-1beta and a low bacterial load in the joints, whereas rapid onset and worsening of articular lesions in those treated at -2 hours corresponded to early and sustained levels of IL-6.The findings of this study demonstrate that the effects mediated by IFNgamma on GBS-induced arthritis may be detrimental or beneficial, depending on the time of administration of IFNgamma in relation to infection with the antigen.

Summary This study is based on skeletons and mummies belonging to 582 individuals excavated at sites of Pueblo Viejo, Cahuachi, Estaqueria and Atarco in the Nasca valley, South Coast of Peru. Archaeological evidence distinguishes three cultural phases: Nasca (400 BC–550 AD), Wari (600–1100 AD) and Chincha (1100–1412 AD). Since the Chincha human remains were too exiguous (27 individuals), only Nasca and Wari were considered. For the Nasca population, sex ratio was 113 men to 100 women (53% of males); for the Wari population, sex ratio was 117 men to 100 women (54% of males). The palaeodemographic data show that the infant mortality rate was 33‰ for Nasca and 105‰ for Wari. Life expectancy was 38–43 years for Nasca and 31–36 years for Wari. Death percentages in all the age groups increased from Nasca to Wari phase. ANOVA and t-test for paired comparison were applied in order to examine if dental and bone ages were statistically different. Long bones and teeth showed an allometric development, and the age estimated from the tooth formation and eruption was generally higher than the age estimated from the maximum lengths of long bones. The anthropological study of the Nasca valley skeletal populations confirmed the archaeological hypothesis of worse conditions of the Wari population in comparison with the previous Nasca people.

To determine the accuracy of drug-susceptibility testing (DST) for isoniazid, rifampicin, ethambutol and streptomycin in a provisional network of 22 regional laboratories in Italy.Methods, definitions and reference Mycobacterium tuberculosis strains were derived from the WHO/IUATLD Global Project on Anti-tuberculosis Drug Resistance Surveillance. The laboratories were selected based on technical skills required by the project, the number of DST performed annually and geographic localisation. The results (sensitive/resistant strain) were compared with the gold standard (global project results). Sensitivity (ability to detect true resistance), specificity (ability to detect true susceptibility), positive predictive values for resistance and susceptibility, efficiency and reproducibility were calculated in two rounds.Eighteen of 22 laboratories completed the first round of proficiency testing for the four drugs. Sensitivity was 76.6%, specificity 97.2%, predictive value of a resistant test 89.8% and of a susceptible test 86.8%, efficiency 87.8% and reproducibility 92.8%. A second round was performed by all those laboratories that did not achieveor = 90% agreement with the results of the Global Project. Overall, after the second round, all the parameters except specificity improved, exceeding 90%.A network of 15 regional laboratories that fulfil the quality criteria for determining the susceptibility of M. tuberculosis to the four primary antituberculosis drugs was established in Italy.

A survey of antimicrobial resistance in Streptococcus pyogenes, performed within the framework of a national surveillance program, has revealed a dramatic increase in resistance of S. pyogenes to erythromycin in most areas of Italy. In virtually all the centers that provided data for 3 consecutive years, the incidence of erythromycin-resistant strains increased twofold to 20-fold from 1993 to 1995 and was greater than 30% in five of the 14 centers participating in the study. The clonality of erythromycin-resistant isolates was studied in 15 strains isolated from different patients at the Institute of Microbiology of Verona University (Verona). The features of the Verona isolates and the substantially different rates of erythromycin and clindamycin resistance observed in most centers suggest that the spread of different resistance genes in multiple clones might be occurring throughout the country.

A retrospective analysis of susceptibility data available for Group A streptococcal isolates collected between January 1990 and January 1996 at the Hospital Microbiology Laboratory of Monza (North Italy), showed a sharp rise in the erythromycin resistance rates during the last 3 years. Streptococcus pyogenes resistant to erythromycin accounted for approximately 1% of strains isolated between 1990 and 1992; the percentage then rose from 5% in 1993 to almost 39% in 1995. In January 1996, the resistance rates peaked to 81%. A prospective controlled study performed between March and May of 1996 to determine the percentage of erythromycin-resistant Group A streptococci isolated in Monza from untreated children with acute pharyngo-tonsillitis, gave further confirmation of a high rate of erythromycin resistance (47%) in this area. Molecular characterization by T-serotyping and pulse-field gel electrophoresis analysis of 25 erythromycin-resistant Group A streptococcal isolates, showed a relatively high degree of heterogeneity among these strains, demonstrating that the increased resistance is not caused by the spread of a single clone.

A survey of antibiotic resistance in Streptococcus pyogenes in Italy showed a sharp increase in erythromycin resistance. In 1993, the incidence of erythromycin-resistant strains was on average 5.1%, with marked variations by geographic area. Two years later, the incidence of these strains had registered a 1.5- to roughly 20-fold increase, with a mean value of 25.9%, exceeding 40% in three centers out of 13 and 30% in another four. For all the strains studied, normal levels of susceptibility to penicillin were reported.

The gene encoding a class A beta-lactamase was cloned from a natural isolate of Mycobacterium fortuitum (blaF) and from a high-level amoxicillin-resistant mutant that produces large amounts of beta-lactamase (blaF*). The nucleotide sequences of the two genes differ at 11 positions, including two in the region upstream from the coding sequence. Gene fusions to Escherichia coli lacZ and transcription and expression analysis of the cloned genes in Mycobacterium smegmatis indicated that high-level production of the beta-lactamase in the mutant is mainly or wholly due to a single base pair difference in the promoter. These analyses also showed that transcription and translation start at the same position. A comparison of the amino acid sequence of BlaF, as predicted from the nucleotide sequence, with the determined N-terminal amino acid sequence indicated the presence of a typical signal peptide. The fusion of blaF (or blaF*) to the E. coli gene phoA resulted in the production of BlaF-PhoA hybrid proteins that had alkaline phosphatase activity. These results demonstrate that phoA can be used as a reporter gene for studying protein export in mycobacteria.

A 43-year-old male who sustained a superficial hand injury developed streptococcal toxic shock-like syndrome and died within 48 hours. The clinical course of the illness in this previously well patient was rapid and fulminant. The organism responsible was a group A beta-hemolytic streptococcus which was identified as opacity factor negative, M serotype 1, T type 1. The organism produced streptococcal pyrogenic exotoxins B and C, but no detectable exotoxin A although it carried speA, the gene for exotoxin A. This is the first case reported in Italy, and further emphasizes the virulence of these organisms and the rapidity with which the illness can progress.

A food-borne outbreak of pharyngitis from group A streptococcus developed in people attending wedding banquets in the same restaurant on July 5-8, 1986. Of the 300 people interviewed, 179 reported illness; pharyngeal swabs were taken from 115 ill people; from 63 (53%) of them group A streptococci, belonging to serotype T28, M28, were isolated. Statistical analysis performed using chi-square and Cochran's test showed that a prawn hors-d'oeuvre served on July 5 and squills or/and custard cake served on July 7 could have been a possible source of infection. Six people on the staff, 5 of whom belonged to the family of the restaurant manager, and the manager's three young daughters were colonized by the same group A serotype. A possible previous diffusion of the strain among the staff followed by contamination of the food was suspected.

We have established an experimental murine model to gain insight into the pathogenicity and clinical features of type IV group B streptococcus (GBS) infections. Adult CD-1 mice were challenged intravenously with 10(7) type IV GBS cells, inducing systemic invasion. Most of the animals were able to clear the infection from the blood, brain, and lungs within 2 weeks and from the spleen and liver within 1 month. However, the animals were unable to clear the microorganism from the joints and kidneys during the 60-day observation period. About 80% of the mice challenged intravenously with type IV GBS manifested early septic arthritis, which evolved from an acute exudative synovitis to permanent lesions characterized by irreversible joint damage and ankylosis. Induction of persistent septic arthritis was dependent on the number and viability of microorganisms inoculated and was unrelated to the strain of type IV GBS and the growth phase of the inoculum. Type-specific antibodies of both immunoglobulin M and G classes could be detected by agglutination and enzyme-linked immunosorbent assay from days 7 and 14, respectively; immunoglobulin G antibodies persisted for more than 40 days. Complexes of antibodies and group- and type-specific antigens were detected in mouse sera 24 h after infection and persisted up to day 22. These results were obtained an experimental model of type IV GBS chronic infection with early development of septic arthritis, which could be useful in future studies of pathogenicity and immune mechanisms involved in the host resistance to this microorganism.

Sensitivity and specificity of three commercial latex agglutination tests, i.e. Streptex, Wellcogen (Wellcome Diagnostics, Dartford, England) and Directigen (Becton Dickinson, Baltimore, USA) were evaluated on 233 vaginal swabs and 208 urine specimens after 4h culture in comparison with traditional cultural and identification methods. On vaginal swabs sensitivity of Wellcogen and Streptex was shown to be comparable (43% and 37% respectively), but both tests gave several false positive results; Directigen test showed higher (100%) specificity, but its sensitivity was very low. On urine cultures all the tests were shown to be unsatisfactory in comparison with traditional methods, sensitivity and specificity being demonstrated to be poor.

Summary In the absence of previous published studies from Italy on the epidemiology of group B streptococci we investigated 1516 mothers at delivery and 1294 neonates in three hospitals. Of mothers in labour, 7·5% were colonized with group B streptococci and 4·9% of their babies. Of the neonates born to a positive mother 45·1% were colonized, whilst only 2·2% of babies born to a negative mother were colonized. For the mothers, the vagina was colonized more often (7·3% of all women) than the cervix (6·0%), the urethral meatus (3·9%) or the rectum (2·9%). For the neonates, the rates of colonization of the throat, external auditory canal, and the umbilicus were 3·2%, 3·0% and 2·6%, respectively. The distributions of the serotypes were similar to that reported from other parts of Europe and USA and vertical transmission of group B streptococci was demonstrated in most of the mothers and their neonates. Of 30 mother-neonate pairs, 25% of mothers carried group B streptococci intermittently and 58% had persistent carriage until the 90th day postpartum, the rectum being the commonest positive site. Of 20 infants that were positive at birth, only six were still positive on the 15th day and none by the 90th day of life. Of 1294 infants, four (0·3%) developed early-onset sepsis with group B streptococci and one died. The overall incidence of clinical infection amongst colonized infants was 6·2%.

We have investigated the role of lipoteichoic acid in mediating the adherence of different serotypes of group B streptococci to human adult and neonatal epithelial cells. Pretreatment of neonatal buccal and vaginal epithelial cells with lipoteichoic acid, but not with deacylated lipoteichoic acid, induced a marked inhibition in the adherence of all strains tested. Pretreatment of bacteria with substances known to bind lipoteichoic acid, such as monoclonal and polyclonal antipolyglycerophosphate antibodies and albumin, also resulted in adherence inhibition. Group B streptococci adhered in 6- to 10-fold-higher numbers to buccal epithelial cells from neonates older than 3 days than to those from neonates less than 1 day old. This increase in receptiveness for group B streptococci was paralleled by an increased ability of epithelial cells from older neonates to bind group B streptococcal lipoteichoic acid. These data suggest a role for the lipid portion of lipoteichoic acid in the adherence of different serotypes of group B streptococci to vaginal and neonatal epithelial cells.

International audience; When a vaccine in three different concentrations (non-diluted, half-strength and one-third strength) was used on a study population of 159 students, six weeks after the vaccination only the vaccine at one-third strength showed small vaccination lesions in comparison with those of the other two concentrations. There is no evidence of any significant difference between them with respect to the positive reaction to the tuberculin testing. After one year, the number of subjects with a positive vaccination scar is drastically reduced in the case of the vaccine at one-third strength. As regards the tuberculin reaction, even if the difference in the number of positive values is not significant, the reaction size for the one-third and one-half strength dose diminishes significantly with respect to that observed at six weeks.

Several species of mycobacteria have been reported to produce beta-lactamases, but only those of M. smegmatis have been purified and partially characterized. This study is a preliminary report of the presence of beta-lactamase activity in M. fortuitum, strain Cow 18. A partial purification of the beta-lactamase has also been achieved. M. fortuitum was grown in either Sauton or glucose-yeast extract medium (GYM) and sonicated cells or culture filtrates were assessed for the presence of beta-lactamase activity using a chromogenic compound (PADAC) as substrate. Cells growing in GYM medium released a detectable amount of enzyme, whereas microorganisms showed only intracellular beta-lactamase activity. The enzyme present in the culture filtrate of M. fortuitum Cow 18 was concentrated by Amicon ultrafiltration and partially purified through Sephadex G-75 and QAE-Sephadex A-50 ion exchanger columns. The spectrum of activity of this enzyme included some cephalosporins (cephaloridine, cephalothin) and some penicillins, the hydrolysis of the former being generally more pronounced. Furthermore, cefoxitin, ceftazidime and cefotaxime were not hydrolysed.

The susceptibility of 34 strains of M. fortuitum to several antimicrobial agents was comparatively tested by the disk diffusion and the agar dilution methods. The results obtained by these two methods essentially showed that the microorganism was fully sensitive to amikacin and kanamycin and only partially sensitive to sisomicin and rifampicin. Streptomycin, erythromycin and cephotaxime were inactive. The disk diffusion method seems advisable as a rapid screening procedure for antibiotic susceptibility testing M. fortuitum.

During the month of February 1982 in an orthopedic department (37 patients admitted), episodes of diarrhoea occurred in 9 patients, one of these resulting in the death of one patient. From the stool cultures of the patients methicillin/gentamicin resistant S. aureus (MRGRSA) was isolated. The clinical, microbiological and epidemiological analysis demonstrated the staphylococcal origin of the enterocolitis. The statistical analysis brought to light a significant increase in the acquisition of the infection in relation to age, surgical intervention, catheter, ulcers and antibiotic therapy. The medical staff, colonized at hand and nose by the epidemic strain contributed probably to the transmission from person to person. Antimicrobial therapy with oral vancomycin of colonized patients and application of topical ointment (betadine) on personnel eliminated colonization with methicillin/gentamicin resistant S. aureus.

Enzymatic patterns, antibiotic sensitivity, penicillinase, production, mercury ion resistance have been studied in St. saprophyticus strains in comparison with St. epidermidis, both isolate from urinary infections of hospital patients. The St. saprophyticus has shown to have a lower number of virulence factors, to be more sensitive to antibiotics and to have a lower potential epidemiological value.

The ability of S. bovis 83/5364, glucan-positive (biotype I) and S. bovis R 81/536 glucan-negative (biotype II) to adhere to buccal epithelial cells (BEC) by lipoteichoic acid (LTA) was examined. LTA from both biotypes was prepared by cold phenol extraction from supernatants of penicillin supplemented cultures and partially purified by Sepharose CL-6B chromatography. Both glucan-positive and glucan-negative S. bovis strains adhered to BEC, but biotype I seemed to be more adhesive. For both biotypes the adhesion was not significantly inhibited by treatment of the bacteria with anti-LTA serum, while the preincubation of BEC with LTA, extracted from S. agalactiae, or cardiolipin strongly decreased the S. bovis binding.

The possible in vitro synergistic effect between amikacin and cefoxitin against 29 clinical isolates of M.fortuitum was studied either by the agar dilution checkerboard technique and by the killing curve on Mueller Hinton agar plus OADC enrichment and on 7H11. As evaluated by FIC index on MHA a synergistic effect was noted on 20 (68.96%) strains tested, an additive effect on 8 (27.60%) isolates, and a possible antagonistic effect only on 1 (3.44%) isolate. On 7H11 a synergistic effect was shown on 10 (38.50%) isolates, an additive effect on 12 (46.10%) and an antagonistic effect on 4 (15.40%) isolates. The killing curve observed on three strains (562, 565 and 505), specially selected as representative of synergistic (562), additive (565) and antagonistic effect (505) on the basis of their checkerboard results, showed synergistic effect on strains 562 and 565 as well as on strain 505 where complete killing was obtained in 24 h by a combination of two antibiotics used at 1/2 Mic. By the killing curve technique both antibiotics were found to be bactericidal but the effect was earlier for amikacin than for cefoxitin.

In the absence of previous published studies from Italy on the epidemiology of group B streptococci we investigated 1516 mothers at delivery and 1294 neonates in three hospitals. Of mothers in labour, 7.5% were colonized with group B streptococci and 4.9% of their babies. Of the neonates born to a positive mother 45.1% were colonized, whilst only 2.2% of babies born to a negative mother were colonized. For the mothers, the vagina was colonized more often (7.3% of all women) than the cervix (6.0%), the urethral meatus (3.9%) or the rectum (2.9%). For the neonates, the rates of colonization of the throat, external auditory canal, and the umbilicus were 3.2%, 3.0% and 2.6%, respectively. The distributions of the serotypes were similar to that reported from other parts of Europe and the USA and vertical transmission of group B streptococci was demonstrated in most of the mothers and their neonates. Of 30 mother-neonate pairs, 25% of mothers carried group B streptococci intermittently and 58% had persistent carriage until the 90th day postpartum, the rectum being the commonest positive site. Of 20 infants that were positive at birth, only six were still positive on the 15th day and none by the 90th day of life. Of 1294 infants, four (0.3%) developed early-onset sepsis with group B streptococci and one died. The overall incidence of clinical infection amongst colonized infants was 6.2%.

Neuraminidase production by reference strains of various group B streptococci serotypes was investigated before and after serial passages in mouse. The enzyme production was tested in culture filtrates using bovine submaxillary mucin as substrate. Although passages in mouse markedly increased the virulence of all the strains it was not possible to demonstrate a relationship between the increased virulence and the enzyme production.

In order to elucidate the role of beta-lactamase in the resistance of M. fortuitum to beta-lactams, M. fortuitum ATCC 19542 and three mutants, strains D 316, D 319 and D 170 obtained from it by nitrosoguanidine treatment, were studied. Furthermore the kinetics of the beta-lactamase production during the bacterial growth and many biochemical and enzymatic characteristics of parent and mutant strains were investigated. Amoxicillin MICs well correlated with the beta-lactamase production in the high producer strains D 316 and D 319; on the contrary in strain D 170 a high MIC was joined with a moderate production of the enzyme showing that not only beta-lactamase but also other mechanisms can be effective in the resistance of M. fortuitum to beta-lactams. Clavulanic acid, an inhibitor of beta-lactamase, reduced MICs to amoxicillin in high and in low producer strains. The production of extracellular beta-lactamase occurred in a M. fortuitum mutant strain mainly during the stationary phase, indicating that a cell wall damage or initial autolysis could be responsible for the release of enzyme. Enzymatic and biochemical characteristics were not affected by nitrosoguanidine treatment except for nitrate test which showed only a weak positivity in high producer strains.

This report details of an investigation on a significant increase in nosocomial bacteremias due to multiply-resistant Pseudomonas aeruginosa strains which occurred in a hematological ward. Serotyping according to Habs method showed a high frequence of the serotype 12. Control cultures identified in the hospital building water reservoirs the presence of the organism. After disinfection of these water reservoirs, the frequence of nosocomial septicemias caused by serotype 12 Pseudomonas aeruginosa strains on the overall bacteremic episodes declined immediately and showed a declining trend in the following 13 months period. To conclude serotyping of Pseudomonas aeruginosa is a useful epidemiological marker and allows to discover from where the diffusion of the organism responsible of outbreaks starts.