Retinal integration of grafts of brain-derived precursor cell lines implanted subretinally into adult, normal rats

The ability of in vitro-expanded neural precursor cells or cell lines to differentiate following transplantation has significant implications for current research on central nervous system repair. Recently, interest has been focussed on grafts of such neural precursors implanted also into the eye or retina. Here, we demonstrate with a non-traumatizing subretinal transplantation method, that grafts of the two immortalized brain-derived cell lines C 17-2 (from postnatal mouse cerebellum) and RN33B (from the embryonic rat medullary raphe) survive for at least up to four weeks, after implantation into the adult normal rat retina. For both cell lines, implanted cells gradually integrate into all major retinal cell layers, including the retinal pigment epithelium, and judged by the morphology differentiate into both glial- and neuron-like cells, as shown by thymidine autoradiography, mouse-specific in situ hybridization, and using immunohistochemistry to detect the reporter gene LacZ. Our results suggest that these and other similar neural cell lines could be very useful in the continuous experiments in models of retinal disorders to further assess both the cell replacement and ex vivo gene therapy approaches.

Penicillin-resistant pneumococci in southern Sweden, 1993-1997

In Malmöhus County, Southern Sweden, the frequency of penicillin-resistant pneumococci in nasopharyngeal specimens of outpatients with respiratory tract infections increased from 3.1% in 1993 to 7.6% in 1995, and was thereafter rather stable. Over the period, 82-85% of the patients with penicillin-resistant strains were children 0-6 years of age. Ten groups/types constituted 96-100% of the penicillin-resistant isolates. Grouping/typing of 200 consecutive isolates in October and November each year indicated that the distribution of groups/types amongst patients with respiratory tract infections was rather constant over the period. The frequency of penicillin-resistant pneumococci of groups/types 6, 14, and 19 roughly corresponded to the occurrence of these groups/types amongst the consecutive isolates. Other groups/types 9, 15, 21, and 23 either showed a pronounced increase or decrease, which could not be related to the prevalence of these groups/types among the consecutive isolates or degree of antibiotic resistance. Penicillin-resistant group 9, introduced in the area in 1993, consisted of one single clone, 9V. The stabilized level of penicillin resistance since 1995 may be related to the preventive measures implemented in the area, including day-care interventions, and measures to reduce the prescription rate of antibiotics to outpatients with respiratory tract infections.

Introduction and clonal spread of penicillin- and trimethoprim/sulfamethoxazole-resistant Streptococcus pneumoniae, serotype 9V, in southern Sweden

As part of an intervention project, all patients in Malmöhus county with a culture positive for penicillin-resistant pneumococci, MIC > or =0.5 mg/L (PRP), have been registered since January 1995. Nasopharyngeal specimens were obtained from family members and close contacts of identified carriers. Children were denied attendance at regular day-care until PRP-negative. In 1995 and 1996, PRP were isolated from 882 individuals, 364 of whom had clinical infection and the remaining of whom were asymptomatic carriers. In 49%, the PRP were of serogroup 9, with MIC of penicillin 0.5-2.0 mg/L and resistance to trimethoprim/sulfamethoxazole. Further analyses with serotyping and genetic fingerprinting suggested strongly that most of the isolates belonged to a single serotype 9V clone. Month by month, an apparently continuous spread appeared from one municipality to a neighboring one. In most communities, the serotype 9V PRP appeared and disappeared within a few months. The active procedures of the intervention project may have limited the spread of the clone in the county.

Intraoperative contamination of synthetic vascular grafts. Effect of glove change before graft implantation. A prospective randomised study

OBJECTIVES

to investigate the incidence of intraoperative graft contamination, bacterial species and the influence of change of surgeon's gloves on contamination.

DESIGN

a prospective randomised study.

MATERIALS AND METHODS

forty patients had implantation of synthetic vascular grafts. All patients received intraoperative cloxacillin (2.0 g) or clindamycin (0.6 g) intravenously. The procedures were randomised to two groups: Group 1 - surgeons changed the gloves before the first contact with the vascular prosthesis and Group 2 - operation without glove change. The growth of all bacterial species from graft segments and from the gloves was recorded. The susceptibility to antibiotics was tested.

RESULTS

the number of contaminated grafts was similar in the two groups. Growth of bacteria was recorded from 92.5% (37/40) of the graft segments and 33% (51/156) of glove imprints. Of the cultured species, 75% and 47%, respectively, were identified as coagulase-negative staphylococci (CNS). Twenty-eight per cent of CNS were resistant to cloxacillin, 15% to clindamycin, and 10% to cloxacillin and clindamycin. In all, 25% of the CNS strains were resistant to the prophylactic antibiotic used. In 50% of cases, the antibiogram of the CNS strain recovered from gloves agreed with that of the strain harvested from the graft.

CONCLUSIONS

a high incidence of graft contamination was found which was not reduced by changing gloves. However, changing gloves did seem to reduce the number of bacterial species.

Disk with high oxacillin content discriminates between methicillin-resistant and borderline methicillin-susceptible Staphylococcus aureus strains in disk diffusion assays using a low salt concentration

A separation between mecA+ strains of Staphylococcus aureus and strains lacking mecA was achieved by the disk diffusion assay and the agar dilution method, utilizing disks containing 5 microg of oxacillin and inocula of approximately 5 x 10(5) CFU/spot, respectively, provided that agar with 0 to 0.5% NaCl and incubation at 30 degrees C were employed. The 5-microg oxacillin disks clearly discriminated between borderline methicillin-susceptible and mecA+ strains. The oxacillin MICs were more affected by the inoculum density and salt concentration than were the methicillin MICs, and oxacillin MICs of 4 to 16 microg/ml were obtained for strains lacking mecA. Significantly higher levels of beta-lactamase production and reduced oxacillin susceptibilities were recorded for strains lacking mecA, in particular strains of phage group V, when agar with >/=2% NaCl was used than when agar with 0 to 0.5% NaCl was employed. The results indicate that the borderline methicillin-susceptible phenotype is a salt-dependent in vitro phenomenon of questionable clinical relevance.

Bacteraemic pneumococcal infections in Southern Sweden 1981-96: trends in incidence, mortality, age-distribution, serogroups and penicillin-resistance

In a survey of pneumococcal blood isolates from patients in Southern Sweden, 560 isolates were found between 1981 and 1996. Between these years, the incidence of pneumococcal bacteraemia increased from 5.2 to 15.2/100,000/y. The eight most common serogroups/types (14, 7, 9, 6, 23, 3, 4 and 19) accounted for > 75% of the isolates, and 96.4% of the isolates were of serogroups/types represented in the present vaccine. A male preponderance (1.17:1) was noted, and the men were younger than the women (mean 57 vs 63 y of age; p < 0.05). The overall case-fatality rate during the period was 19%. Seven isolates with reduced susceptibility to penicillin were noted, all from 1991 to 1996. The increasing incidence of pneumococcal bacteraemia could not be explained by any of the following factors; age or sex of the patients, changes in prevailing serogroups/types, variations in vaccine use, emergence of penicillin-resistance, more liberal indications for blood cultures or improved culture methods.

Identification of mecA-related oxacillin resistance in staphylococci by the E test and the broth microdilution method

A set of 165 strains of different staphylococcal species, 67 Staphylococcus aureus, 71 novobiocin-sensitive coagulase-negative staphylococci (CNS) and 27 novobiocin-resistant CNS was used. The oxacillin and methicillin MICs were recorded after 24 and 42 h of incubation at 35 degrees C and at 30 degrees C. Significantly higher MICs were recorded at 30 degrees C compared with 35 degrees C. While a poor discrimination between mecA-positive and mecA-negative strains was obtained with methicillin, the oxacillin MICs enabled identification of resistant strains under certain conditions. The distribution of MICs differed between the three groups of species. Separation of uninduced mecA-positive (> or = 4.0 mg oxacillin/L) and mecA-negative (< or = 2.0 mg oxacillin/L) strains of S. aureus was only achieved with the E test and after 42 h of incubation. Oxacillin-induction yielded higher MICs for mecA-positive strains of S. aureus, and a separation from mecA-negative strains was achieved with the E test after 24 h and with the broth microdilution method after 42 h. Separation of mecA-positive and mecA-negative strains of novobiocin-sensitive CNS required agar supplemented with 5% blood, incubation of MIC trays and E test for 42 h, and species-specific oxacillin MIC breakpoints (S < or = 0.5 mg/L and R > or = 1.0 mg/L). The mecA-positive and mecA-negative strains of novobiocin-resistant CNS were clearly separated after 24 h of incubation by either method.

Treatment failure in streptococcal pharyngotonsillitis. An attempt to identify penicillin tolerant Streptococcus pyogenes

Penicillin tolerance in group A streptococci has been suggested to cause treatment failures in pharyngotonsillitis. In the present study, group A streptococci from patients with pharyngotonsillitis, who healed (n = 33) or failed (n = 25) on phenoxymethylpenicillin therapy for 10 days, as well as isolates obtained following the first (n = 25) and second (n = 7) failure were tested for penicillin tolerance by a plate-screening method. For most strains, the survival rate after a 6-h exposure of log-phase bacteria (10(4) CFU) to a phenoxymethylpenicillin concentration of 4 times the minimum inhibitory concentration (MIC) was below 0.1%. Five strains from cases of failure, exhibiting survival rates of 0.2-0.5%, were subjected to time killing kinetic tests with phenoxymethylpenicillin at 12 times the MIC. At 6 h each of the strains from failures showed survival rates below 0.03%. One single group A strain, previously selected in our laboratory, showed a survival rate of 0.4-1.2%, which was close to tolerance as defined. Four streptococcal strains, earlier reported as tolerant, showed survival rates of > 1% but were found to be group G. Penicillin tolerance does not significantly contribute to failures in penicillin therapy of group A streptococcal pharyngotonsillitis, but seems to be a common property of group C and G streptococci.

Additive effect of clarithromycin combined with 14-hydroxy clarithromycin, erythromycin, amoxycillin, metronidazole or omeprazole against Helicobacter pylori

The in-vitro activities of clarithromycin, 14-OH clarithromycin, erythromycin, amoxycillin, metronidazole and omeprazole against Helicobacter pylori were determined at pH 7.2 and 5.5. At pH 5.5 the activities of clarithromycin and erythromycin decreased approximately 16 times while 14-OH clarithromycin was less influenced. Chequerboard titration indicated that the combined activity of clarithromycin and the other compounds was additive.

Prevention of recurrent acute otitis media in otitis-prone children by intermittent prophylaxis with penicillin

The question whether penicillin V (pcV) given intermittently upon signs of upper respiratory tract infections (URTI) in otitis-prone children might prevent recurrent bouts of acute purulent otitis media (AOM) is addressed. As compared with continuous long-term antibiotic treatment as prophylaxis in otitis-prone children, intermittent administration would reduce the overall consumption of antibiotics. Seventy-six otitis-prone children less than 18 months of age were included in this double-blind, randomized, placebo-controlled multicentre study. Follow-up was from January till June. One hundred and twenty-three episodes of AOM occurred. The number of AOM episodes was reduced by 50% in the children on pcV during URTI episodes as compared with those on placebo. No obvious ecological drawbacks were noted. Thus, the described mode of pcV administration seems to be a rational and safe way to reduce the number of AOM episodes in otitis-prone children.

Increasing resistance to penicillin in Streptococcus pneumoniae in southern Sweden

The susceptibility to penicillin of 6 prevalent pneumococcal types isolated from nasopharynx in 1992 was compared with that of corresponding types from 1980-82. The 6 types or groups, 6, 9, 14, 15, 19 and 23, constituted 78% of consecutive isolates. 19/204 isolates in 1992 were intermediately resistant (MIC 0.12-1.0 mg/l) in comparison with 1/194 from 1980-82 (p < 0.001). Resistant strains (MIC > or = 2 mg/l) were not found. Of group 15, no fewer than 10/31 isolates were intermediately resistant, which may support the clonal origin and spread of penicillin-resistant pneumococci. At least 5.0% of nasopharyngeal isolates are now intermediately resistant to penicillin. This figure is substantially higher than the 2% earlier reported in Sweden.

Clindamycin in persisting streptococcal pharyngotonsillitis after penicillin treatment

239 patients with streptococcal pharyngotonsillitis completed treatment with phenoxymethyl penicillin 12.5 mg per kg body weight b.i.d. for 10 days. At examination after completing therapy, throat specimens from 53 patients (22%) yielded growth of group A streptococci of the same. T-type as the initial culture (bacterial treatment failure). 20 of these 53 (38%) had symptoms and signs of tonsillitis (clinical and bacterial treatment failure). 48 of the patients with bacterial failure were randomly allocated to phenoxymethyl penicillin or clindamycin in an open design; 22 of them received a second course of phenoxymethyl penicillin for 10 days and 26 were given clindamycin, 6.5 mg per kg body weight b.i.d. (children) or 300 mg t.i.d. (adults) for 10 days. After completing their treatment, 14 of 22 patients (64%) given phenoxymethyl penicillin harboured the same T-type as in the previous two cultures, while group A streptococci were not recovered from any of the 26 patients receiving clindamycin. In patients with clinical failure after phenoxymethyl penicillin treatment, a new course with this drug is not motivated. In that situation clindamycin seems to be an efficient choice.

Erythromycin in acute laryngitis in adults

Moraxella catarrhalis and Hemophilus influenzae are isolated from the nasopharynx in 50% to 55% and 8% to 15%, respectively, of cases of acute laryngitis in adults. This finding indicates that these organisms, M catarrhalis in particular, are in some way involved in the pathogenesis of the disorder. In the present double-blind, placebo-controlled trial, the effect of erythromycin ethylsuccinate (0.5 g twice a day for 5 days) on the elimination of nasopharyngeal pathogens and reduction of clinical signs of upper respiratory tract infection, as well as on subjective complaints, was evaluated in 106 adults with acute laryngitis. The bacterial isolation rates at presentation were M catarrhalis 50%, H influenzae 18%, and Streptococcus pneumoniae 4%. In the 99 patients who completed the study, the elimination of M catarrhalis after 1 week was better in the erythromycin group (25 of 30 cases) than in the placebo group (6 of 19 cases; p < or = .00038). The elimination of H influenzae was unaffected by erythromycin. Otolaryngologic examination did not reveal any significant group differences regarding laryngitis, pharyngitis, or rhinitis. Voice quality was improved after 1 week, irrespective of treatment. However, as compared to the placebo group, the erythromycin group reported fewer voice complaints after 1 week and fewer coughing complaints after 2 weeks. As acute laryngitis in adults is self-limiting, and subjective symptoms are spontaneously reduced after 1 week in most cases, antibiotic treatment does not seem warranted as a general policy. However, erythromycin may be justified in patients who are professionally dependent on voice function.

Characterization of cell-bound papain-soluble beta-lactamases in BRO-1 and BRO-2 producing strains of Moraxella (Branhamella) catarrhalis and Moraxella nonliquefaciens

In Moraxella (Branhamella) catarrhalis and Moraxella nonliquefaciens strains isolated from clinical specimens in the south of Sweden two variants of beta-lactamase were distinguished by isoelectric focusing (IEF). The BRO-1 (Ravasio type) enzyme was the most common in Branhamella catarrhalis, constituting about 90% of the beta-lactamase found in this species, while the BRO-2 enzyme (1908 type) was as common as BRO-1 in Moraxella nonliquefaciens. The determinants mediating the production of BRO-1 and BRO-2 were both transferable by conjugation. Cell-bound beta-lactamase from reference strains producing BRO-1 and BRO-2 could be solubilized by papain digestion. The isoelectric point of the solubilized enzymes differed distinctly between BRO-1 (pI 6.5) and BRO-2 (pI 6.9). The molecular species of BRO-1 and BRO-2 released by papain digestion were purified by affinity chromatography with phenylboronic acid agarose gel. They had identical molecular weights of approximately 28,000. Their kinetic constants were indistinguishable for a number of substrates and beta-lactamase inhibitors.

Production of betalactamase by respiratory tract bacteria in children: relationship to antibiotic use

Sales of antibiotics have increased in Sweden during the past decade. This has been paralleled by an increase in the frequency of beta-lactamase-producing respiratory tract bacteria. To investigate the effects of regional differences in use of antibiotics on beta-lactamase production in respiratory tract bacteria, we collected nasopharyngeal specimens and information about antibiotic use from 1133 children attending day-care centres in four rural municipalities with low use, and one urban municipality with high use of antibiotics, use being assessed from pharmacy sales. The frequency of beta-lactamase production among isolates of Branhamella catarrhalis and Moraxella nonliquefaciens was significantly higher in the urban municipality. This appeared to be a long-term ecological effect of differences in the level of use of antibiotics between the urban and rural populations, rather than an effect of recent antibiotic treatment of individual patients.

Acute laryngitis in adults: results of erythromycin treatment

Previous studies of acute laryngitis in adults have shown high nasopharyngeal isolation rates of B. catarrhalis and H. influenzae. Phenoxymethylpenicillin had no effect on the clinical course. In the present study, 106 patients with acute laryngitis were treated with erythromycin 0.5 g x 2 V or placebo. During the first week the isolation rate of B. catarrhalis was reduced from 60 to 10% in the erythromycin group compared to 34 to 27% in the placebo group (p less than 0.01). The elimination of H. influenzae, isolated in 19% at the acute visit, did not differ between the two groups. As compared to controls, erythromycin treated patients reported significantly lower scores of subjective voice disturbance after 1 week and cough after 2 weeks. Laryngological examination and voice evaluation failed to reveal any differences between the groups.

Penicillin tolerance in group A streptococci and treatment failure in streptococcal tonsillitis

Penicillin tolerance in Streptococcus pyogenes has been suggested as a possible cause of therapeutic failure in streptococcal phryngitis treated with penicillin. In 144 patients with acute group A streptococcal tonsillitis treated with phenoxymethyl penicillin 12.5 mg per kg body weight b.i.d. for 10 days the same T-type was recovered after treatment in 21%. The recovery rate was higher for non-tolerant strains, 23%, than for tolerant strains, 10% (p greater than 0.05). Of patients with a non-tolerant strain 17% had both clinical and bacterial treatment failure in comparison with 5% infected with a tolerant strain (p greater than 0.05). Reinfection with a new serotype occurred in altogether 3%. The present data did not indicate that penicillin tolerance in group A streptococci is of significance in acute tonsillitis treated with phenoxymethylpenicillin for 10 days.

Emergence and persistence of beta-lactamase-producing bacteria in the upper respiratory tract in children treated with beta-lactam antibiotics

PURPOSE

To assess the ecologic impact, in terms of selection of beta-lactamase-producing respiratory tract bacteria, of a single course of peroral beta-lactam antibiotics.

PATIENTS AND METHODS

One-hundred fifty consecutive children with clinical signs of bacterial respiratory tract infection were randomly assigned to a seven-day course of treatment with either penicillin V, amoxicillin, or cefaclor. Bacteriologic specimens were collected before treatment, at its termination, and at follow-up four weeks later.

RESULTS

All three drugs investigated caused a similar increase in beta-lactamase-producing bacteria, both in absolute and relative terms, an increase that persisted over a period of at least one month after completion of treatment.

CONCLUSION

Penicillin V, amoxicillin, and cefaclor all act as selective agents for beta-lactamase-producing bacteria in the upper respiratory tract. Treatment with a peroral beta-lactam antibiotic puts patients at risk of becoming persistent carriers of beta-lactamase-producing bacteria.

Evaluation of four qualitative methods for detection of beta-lactamase production in Staphylococcus and Micrococcus species

Four qualitative methods for the detection of beta-lactamase production in Staphylococcus and Micrococcus species were evaluated and compared with a quantitative macroiodometric reference method. The disc diffusion test with penicillin G and the cloverleaf method could not separate beta-lactamase-positive from beta-lactamase-negative strains. Two applications of the chromogenic cephalosporin test, using uninduced strains and strains grown on blood agar plates, gave a large number of false negative and false positive results. False negative reactions were most common among uninduced strains, while the false positive reactions were most often recorded for Staphylococcus saprophyticus. A high degree of efficiency was recorded for the nitrocefin spot test, using induced strains grown on antibiotic susceptibility agar, and for the starch-iodine plate method. The starch-iodine plate with methicillin as inducer gave the most reliable results.

Infections and antibiotic prophylaxis in reconstructive vascular surgery

In 98 patients undergoing elective vascular surgery, specimens for bacterial cultures were obtained from urine, ischaemic ulcers, incisional wounds and the implanted grafts. Wound and graft infections were registered and compared with the results of these cultures and suspected risk factors in an attempt to find the source of infections. Antibiotic prophylaxis with cefuroxime was given for 24 h beginning at the start of surgery. Patients with ischaemic ulcers also received "spread prophylaxis", directed against isolated bacteria, for ten days. Three cases of graft infection and twelve cases of wound infection occurred. Positive postoperative cultures from wounds did not correlate with pre- or peroperative cultures. Peroperative cultures revealed small numbers of staphylococcus epidermidis in eleven patients, and none of them developed graft infection. Ischaemic ulcers, diabetes or re-do procedures were not accompanied by a significantly increased frequency of wound or graft infection, although each of three patients with graft infection had one of these risk factors. Bacteria, sensitive to cefuroxime, were found in one graft infection, six wound infections, and in two patients with urosepsis, whereas cefuroxime resistant organisms were isolated from one graft infection and three infected wounds. One of the three graft infections was probably caused by bacteria originating from the patient's ischaemic ulcer. In the other two patients the source of bacteria could not be determined. Cefuroxime seems to be an adequate alternative for prophylaxis of vascular graft infection, but in some patients with bacteriuria or indwelling catheters, a one day regimen may be too short.

Levels of toxic shock syndrome toxin-1 production among Staphylococcus aureus strains and clinical implications

Among 250 S. aureus clinical isolates, the incidence of TSST-1 production was 18.0%. S. aureus var. hominis strains were predominant (95.6%), producing high levels of toxin in vitro, within the range of 0.6 to 4.3 micrograms/ml and exhibiting crystal violet binding with C/D pattern. No correlation was found between the level of TSST-1 production in vitro and the clinical course. Two (3.4%) of the var. bovis strains produced toxin in amounts less than 0.6 micrograms/ml and did not bind crystal violet. None of the 24 var. canis isolates produced TSST-1. Fifty five per cent of the isolates of phage group I produced TSST-1 and corresponded to 57.8% of the toxigenic strains. Two of the 250 patients developed toxic shock syndrome.

Beta-lactamase production in the upper respiratory tract flora in relation to antibiotic consumption: a study in children attending day nurseries

The occurrence of beta-lactamase production in Haemophilus influenzae, Branhamella catarrhalis and Moraxella nonliquefaciens was compared in 191 healthy children attending day nurseries in 2 municipalities differing with regard to the prescription rate of beta-lactam antibiotics. A significantly higher frequency of beta-lactamase production was recorded in M. nonliquefaciens isolated in the municipality with the higher prescription rate. A corresponding difference was not recorded for H. influenzae or B. catarrhalis. Approximately 75% of the nasopharyngeal pathogens H. influenzae, B. catarrhalis and Streptococcus pneumoniae, as well as the commensal M. nonliquefaciens, were eliminated and often replaced by other strains of either species over a period of one month. Although none of the children were on antibiotics a substantial proportion of the acquired strains produced beta-lactamase. This suggested that the carrier rate of beta-lactamase producing strains of the respiratory tract is not only related to the effect of recent antibiotic treatment but also to the prevalence of such strains in the population.

Bacterial contamination in cerebrospinal fluid shunt surgery

Infection is a major complication of cerebrospinal fluid (CSF) shunt treatment with a reported incidence of 8-27%. In the present study, comprising 64 patients operated under strictly defined preoperative and peroperative hygienic measures and without use of prophylactic antibiotics, the infection rate was 3.1%. Out of the 2 cases of shunt infection recorded, 1 was probably caused by peroperative contamination and 1 by postoperative, hematogenous spread. Bacterial cultures from the operation area before incision and during operation were negative in 95% and 78%, respectively, and when positive yielded low numbers of organisms. Specimens taken after skin closure revealed growth in 59% and high bacterial numbers in 20%, mostly of Staphylococcus epidermidis and other resident skin bacteria. In addition, cultures of irrigation solutions, kept in open bowls during operation, yielded bacterial growth in 65% with a predominance of S. epidermidis. Thus, the strict hygienic measures did not prevent bacterial recolonization of the wound during operation. It is conceivable that endogenous as well as exogenous spread may be of importance in this context. The contamination of irrigation solutions indicates that closed irrigation systems should be used in this type of surgery.

Beta-lactamase production in the upper respiratory tract flora

In order to determine the recovery rate of species of the genera Haemophilus and Moraxella (including subgenus Branhamella) from the upper respiratory tract and the incidence of beta-lactamase production within these genera, cultures were made of nose and throat swab specimens and adenoid tissue in 50 children undergoing adenoidectomy. Haemophilus influenzae was isolated from 92% of the children. All children harboured strains of Haemophilus spp. and in 46%, at least one strain produced the TEM-1 beta-lactamase. Branhamella catarrhalis and/or Moraxella nonliquefaciens were isolated from 82% of the children and strains producing the BRO-1 beta-lactamase from 34%. Overall, TEM-1 and/or BRO-1 producing strains were recovered from 60% of the investigated patients. The beta-lactamase production was found to be transferable by conjugation within the respective genera. It is suggested that the apathogenic species may be a source of transferable determinants mediating beta-lactamase production in the upper respiratory tract.

Upper respiratory tract infections. Ecological and therapeutic aspects of beta-lactamase production with special reference to Branhamella catarrhalis

Available data indicate that the most common beta-lactamase produced by Branhamella catarrhalis is plasmid mediated. The same enzyme occurs in Moraxella nonliquefaciens, a commensal in the upper respiratory tract. The ability to produce the enzyme, which is known as BRO-1, can be transferred by conjugation from M. nonliquefaciens to B. catarrhalis. Since the first beta-lactamase-producing strains of B. catarrhalis appeared in 1977, the frequency of beta-lactamase production has increased rapidly; figures as high as 76% have been reported. The plasmid-mediated beta-lactamase TEM-1 occurs in several species of the genus Haemophilus. While the frequency of beta-lactamase production in H. influenzae is reported to be 10-15%, the incidence is significantly higher in non-pathogenic Haemophilus species. Both phenoxymethyl-penicillin and ampicillin promote the occurrence of beta-lactamase-producing strains, but the selective pressure exerted by ampicillin seems to be more pronounced. It may be possible to reduce the ecological effects of the penicillins by avoiding overdiagnosis of the most common bacterial infections of the respiratory tract, and by shortening the courses of antibiotic treatment.

Plasmid-mediated beta-lactamase in Branhamella catarrhalis

The plasmid-mediated beta-lactamase in Branhamella catarrhalis (BRO-1), also occurring in Moraxella nonliquefaciens, differs from other known plasmid-mediated beta-lactamases in Gram-negative bacteria regarding substrate profile and isoelectric point. B. catarrhalis strains previously reported to produce beta-lactamases deviating from BRO-1 were tested, and the beta-lactamases did not differ significantly from BRO-1 in substrate profile, isoelectric point or relative substrate affinity index (RSAI). Further investigations of strains of various geographic origin should be undertaken. RSAI seems to be a useful tool for screening of beta-lactamases in B. catarrhalis since values for a large number of strains can easily be determined. The previously reported conjugational transfer of BRO-1 production within species B. catarrhalis and from M. nonliquefaciens to B. catarrhalis was confirmed. Four bands of extrachromosomal DNA were regularly detected by agarose gel electrophoresis in beta-lactamase-producing as well as in beta-lactamase-negative strains of B. catarrhalis and M. non-liquefaciens, provided that the excessive nuclease activity in the preparations was inhibited.

Characterization of the plasmid-mediated beta-lactamase in Branhamella catarrhalis, with special reference to substrate affinity

The plasmid-mediated Branhamella catarrhalis beta-lactamase BRO-1, also found in Moraxella nonliquefaciens, was characterized as regards substrate profile, isoelectric point and relative substrate affinity index (RSAI) to various substrates and compared in these aspects with the TEM-1 enzyme of Haemophilus influenzae. As measured by a biological assay and with high performance liquid chromatography (HPLC), BRO-1 was found to hydrolyse carbenicillin, mecillinam, methicillin and cefaclor with a higher rate than TEM-1. The only substrates having a relative rate of hydrolysis higher for TEM-1 than for BRO-1 were ampicillin and cephaloridine. The rates of hydrolysis registered with these two methods were comparable for all but 2 of 13 tested substrates. Isoelectric focusing yielded a main band at pH 5.6 and several satellite bands consistent with those reported by other authors for Branhamella enzymes having a substrate profile similar to that of BRO-1. A tenfold or higher difference in RSAI between BRO-1 and TEM-1 was recorded for five of the 15 compounds tested. BRO-1 seems to be the most common beta-lactamase in Bran. catarrhalis, irrespective of geographic origin. Its substrate profile, isoelectric pattern and RSAI differ from those of other known plasmid-mediated beta-lactamases described, thus justifying a specific designation.

Inefficacy of penicillin V in acute laryngitis in adults. Evaluation from results of double-blind study

Patients with acute laryngitis following an upper respiratory tract infection are often treated with antibiotics for their voice complaints, although, to our knowledge, the effect of such therapy has not been examined. In the present study, comprising 100 adults with laryngitis, the rate of resolution of vocal symptoms, as estimated from voice recordings or subjectively by the patients, was the same in patients who received penicillin V (pcV) as in those who received placebo. Similarly, the degree of rhinorrhea/nasal congestion and cough was not significantly influenced by pcV treatment. At the acute visit, nasopharyngeal cultures revealed Branhamella catarrhalis in 50%, Hemophilus influenzae in 15% and Streptococcus pneumoniae in 1% of the patients; the rate of elimination of these bacteria was the same in the pcV as in the placebo group. Thus, while suggesting that B catarrhalis and H influenzae are important for the pathogenesis of the disorder, our results do not provide support for the use of pcV in acute laryngitis.

Phenoxymethylpenicillin and therapeutic failure in acute otitis media

The aim of the present investigation was to determine to what extent beta-lactamase producing Haemophilus influenzae (H.i.) and Branhamella catarrhalis (B.c.) were isolated in cases of failure of treatment of acute otitis media (AOM) with phenoxymethylpenicillin. Among children with suspected therapeutic failure referred to an ENT specialist altogether 11, 15% of those referred, fulfilled the criteria of AOM. Three of them were on erythromycin, 1 on ampicillin and 7 on phenoxymethylpenicillin. In 5 of the children treated with phenoxymethylpenicillin H.i. was isolated from middle ear exudate and/or the nasopharynx. All H.i. isolates were non-capsulated and beta-lactamase negative. One beta-lactamase producing B.c. was isolated from the nasopharynx in a patient with pure culture of H.i. in the ear exudate. The present investigation did not support the suggestion that beta-lactamase producing H.i. or B.c. are major causative agents in therapeutic failures of AOM treated with phenoxymethylpenicillin and did not produce any evidence supporting a change from the recommended ampicillin esters/amoxycillin in therapeutic failures.

Aerobic and anaerobic bacteria in neurosurgical infections. Per-operative culture with flexible contact agar film

Fourteen of 80 patients (17.5 per cent) who underwent elective craniotomy preceded by a strict pre-operative routine of skin decontamination contracted postoperative wound infection. Most of the infections were probably from endogenous sources and from eight of the wounds low-virulent resident skin bacteria, Propionibacterium acnes and/or Staphylococcus epidermidis, were isolated. Since thorough pre-operative preparation of the skin did not reduce the incidence of infection to an acceptable level, antibiotic prophylaxis might be indicated in this type of surgery.

Intrageneric and intergeneric transfer of Branhamella catarrhalis beta-lactamase production

Intrageneric and intergeneric conjugational transfer of beta-lactamase production to a Branhamella catarrhalis recipient is described. The branhamella donor strains were fresh isolates subcultured onto penicillin-containing media directly from the primary plates. A beta-lactamase positive Moraxella nonliquefaciens served as donor in the intergeneric matings. The substrate profiles of the branhamella and moraxella enzymes were indistinguishable as determined by biological assays. Excessive endonuclease activity did not permit a conclusive characterization of isolated extrachromosomal DNA from the branhamella donors.

Secretory otitis media: microbiology of the middle ear and the nasopharynx

Specimens for bacterial culture were obtained from 117 children with secretory otitis media (SOM). From the nasopharynx Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis and group A streptococci were isolated in 79% of the patients. Of 168 ear exudates, 30 yielded growth (18%) from 26 of the patients (22%). Pneumococcal capsular polysaccharides could not be detected in exudates assayed by counterimmunoelectrophoresis. The recovery rate of bacteria from the ear exudates was significantly higher in patients with positive than with negative nasopharyngeal culture (p less than 0.05). The nasopharyngeal pathogens invading the middle ear in SOM seem to survive there for a period of time and are then replaced by other strains according to the fluctuation of the nasopharyngeal flora where approximately 40% of the strains were eliminated and replaced by other strains over a period of 12 to 13 days.

Nosocomial Klebsiella pneumoniae infection: clinical and hygienic measures in a neonatal intensive care unit

An outbreak in a neonatal intensive care nursery of severe infections caused by Klebsiella pneumoniae type K-17 has been studied. Over a 9-month period 20 epidemiologically linked cases of severe septicemia, meningitis and pneumonia were diagnosed. The specific epidemic strain could be identified. After introduction of a policy of hygienic measures the nosocomial infection could be eradicated although colonization still occurred. Thorough handwashing before and after the nursing care of each infant, individual gowning and disposable gloves in the care of infants below 1 500 g were important. The changing bacterial ecology of a neonatal unit should be followed closely by weekly routine throat cultures as well as by cultures of incubators and ventilation equipment. The present investigation has shown the importance of this procedure, which is mandatory for appropriate choice of antimicrobial agents when treating infections in critically ill or very low birth weight infants in the neonatal intensive care unit. Prophylactic antimicrobial treatment is not indicated. Control of K. pneumoniae nosocomial infections can only be achieved by maintaining a high standard of hygiene in the neonatal care.

Risk factors in cesarean section infection

Factors associated with risk of postoperative infection after cesarean section were studied in 321 patients not given antibiotic prophylaxis. Infections occurred in 56 (25%) of the 228 patients who were delivered by emergency cesarean section and in eight (9%) of the 93 patients who underwent elective surgery (P less than .01). These frequencies corresponded well with the infection rates reported after administration of antibiotics in other studies. Risk factors were: duration of operation more than one hour; blood loss more than 800 ml; presence of Staphylococcus aureus in the nares; signs of intrauterine infection before surgery; and failure of progress in labor. The results indicated that obstetric interventions had been performed more frequently in patients at risk of infection, rather than being the real cause of the infections. The importance of strict preoperative hygienic routine is discussed.

Transfer of beta-lactamase production in Branhamella catarrhalis

A beta-lactamase positive Branhamella catarrhalis strain, B.c. 002 PcR, is described. The strain has the ability to transfer beta-lactamase production. The strain was isolated from nasopharynx in an adult patient with long-standing laryngitis. It showed atypical colony morphology.

Serum and saliva concentrations of sulfamethoxazole and trimethoprim in adults and children: relation between saliva concentrations and in vitro activity against nasopharyngeal pathogens

The combination sulfamethoxazole/trimethoprim (SMX/TMP) was given orally to 4 healthy adult volunteers in mean daily doses of 23.0/4.6 mg/kg body weight for 6 days. The serum and saliva concentrations of the drugs were assayed on days 1, 3 and 6. On the first day (0-12 h) there was no measurable concentration of SMX in the saliva. On days 3 and 6 the mean peak levels of SMX in saliva were 7.8 and 9.8 micrograms/ml, i.e. 8-9% of the corresponding mean peak serum levels. In contrast, the concentrations of TMP in saliva were more than twice as high as those in serum. The mean SMX/TMP ratios in saliva days 3 and 6 were 1.3 and 1.4, respectively, i.e. approximately one-twentieth of the mean SMX/TMP ratios in serum. SMX/TMP was also administered to children with serous otitis media. The drug concentrations in saliva were assayed 2-3 h after administration on days 6 and 9 of a 10-day course, with a mean daily dose of 34.5/6.9 mg/kg body weight. The mean saliva concentration of SMX in the children was slightly higher than in adults and the mean TMP concentration about half of that in adults. The mean SMX/TMP ratio in the children's saliva was 4.2. The in vitro activity of SMX/TMP 20:1 and 4:1 was determined against H. influenzae, D. pneumoniae, B. catarrhalis and group A streptococci. H. influenzae, D. pneumoniae and group A streptococci were found more susceptible to TMP than to SMX, while the reverse was true for B. catarrhalis. In the 3 former, the potentiation of SMX by TMP was more pronounced than was the potentiation of TMP by SMX, while the opposite was recorded for B. catarrhalis. The most beneficial effect of the SMX/TMP combination against nasopharyngeal pathogens was recorded for B. catarrhalis and the weakest effect for H. influenzae and group A streptococci. With the exception of B. catarrhalis, the administration of TMP alone to adults may be just as effective against nasopharyngeal pathogens as is the SMX/TMP combination in children.

Prevention of synthetic arterial graft infections by improved hygienic routine and dicloxacillin administration

30/60 patients electively reconstructed with synthetic arterial grafts were randomly treated with dicloxacillin per- and postoperatively for 6 days. Wound infections occurred in 10 of the non-treated patients. 1 of whom had a graft infection. In the dicloxacillin group no wound infection was recorded. Overgrowth with bacteria resistant to isoxazolylpenicillin was not noticed during treatment. No late infections occurred. In comparison with previous results, improved hygienic routines before, during and after operation reduced the incidence of postoperative graft infections from 15 to 3%. As postoperative infections after synthetic arterial graft implantation are serious complications, per- and postoperative antibiotic treatment seems justified as a complement to a rigorous hygienic routine.

Aerobic and anaerobic bacteria in deep infections after total hip arthroplasty: differential diagnosis between infectious and non-infectious loosening

Five separate biopsy samples for bacterial culture were taken at primary total hip arthroplasty in patients without signs of infection and at reoperation of patients with infectious and noninfectious loosening of the prosthesis. Based on the results of the culture, on serologic results and on the erythrocyte sedimentation rate, bacteria of clinical significance could be distinguished from contaminants. Growth in one or two of five biopsy samples was a strong indicator of contamination, while growth in five of five biopsy samples of one or two bacterial species strongly indicated an infection. These diagnostic procedures are applied to differentiate between infectious and noninfectious loosening of the prosthesis. In the delayed infections, the low-virulent aerobic and anaerobic bacteria Staphylococcus epidermidis, Propionibacterium acnes and peptococci were predominant.

High isolation rate of Branhamella catarrhalis from the nasopharynx in adults with acute laryngitis

Branhamella catarrhalis was isolated from the nasopharynx in 55% of 40 noncompromised adult patients suffering from acute laryngitis. Diplococcus pneumoniae and haemophilus influenzae were found in another 5 and 8%, respectively; one patient had group A streptococci in the throat specimen. In 90% of the patients the laryngitis complaints were preceded by symptoms of an acute respiratory tract infection. Two of the patients with B. catarrhalis showed a significant titre conversion against influenza B and parainfluenza type e virus, respectively. Attempts to isolate virus failed in all cases. The results indicate that B. catarrhalis, known to cause acute otitis media in small children and respiratory tract infections in adult compromised hosts, may be involved in the etiology of acute laryngitis in otherwise healthy adults.