In vitro activity of temocillin against gram-negative clinical isolates.

120 consecutive clinical isolates of various species of Enterobacteriaceae and 30 consecutive clinical isolates of Haemophilus influenzae (including 5 which produced beta-lactamase) were assessed for susceptibility to temocillin using a broth microdilution technique and both 'light' (10(3) CFU/ml) and 'heavy' (10(6) CFU/ml) inocula. At the lighter inoculum, 90% of the Enterobacteriaceae were inhibited by temocillin at a concentration of 4 mg/L. 90% of the H. influenzae were similarly inhibited at a concentration of 0.5 mg/L, and no differences were observed between producers and non-producers of beta-lactamase. At the heavier inoculum, a significant inoculum effect was observed: minimum inhibitory concentrations (MICs) increased up to 128-fold for H. influenzae and somewhat less than that for the Enterobacteriaceae. Klebsiella pneumoniae was least affected by inoculum, showing only a 2- to 4-fold increase in the MIC. It is concluded that temocillin is active in vitro against the species tested and warrants further clinical trial.

Multiresistant Klebsiella pneumoniae in a neonatal nursery: the importance of maintenance of infection control policies and procedures in the prevention of outbreaks.

During a 3-week period, nine babies in the neonatal unit of a large teaching hospital in Durban were infected or colonized with Klebsiella pneumoniae resistant to a range of antimicrobial agents including amikacin and cefotaxime. Resistance to cefotaxime was reduced by clavulanic acid in vitro suggesting production of extended-spectrum beta-lactamase activity. All the isolates had the same antibiotic resistance profile, belonged to the same serotype (K17), were non-typable with bacteriophages, and had identical plasmid profiles indicating that they belonged to the same strain. During a 1-day microbiological survey of the ward, the outbreak strain was isolated from the nose and hands of a doctor based in the nursery and from the hands of a nurse and the mother of an infected baby. The strain was also isolated from nine of 67 environmental samples. Investigation revealed that infection control practices which had been instituted following a previous outbreak in the nursery with multi-resistant methicillin-resistant Staphylococcus aureus (MRSA) were not being adhered to. The re-introduction and strict enforcement of these procedures under the supervision of an Infection Control Nurse resulted in the abrupt end of the outbreak.

A microbiological study of neonatal conjunctivae and conjunctivitis.

To investigate the importance of chlamydiae, ureaplasmas, Mycoplasma hominis, and anaerobic bacteria in the pathogenesis of neonatal conjunctivitis in the Harrow population conjunctival specimens from 104 infants with conjunctivitis and 104 similar healthy neonates were examined. The incidence of neonatal conjunctivitis was 8-2%, and no case of neomycin-resistant disease occurred during the study. Staphylococcus aureus, viridans Streptococci, and Escherichia coli were the only micro-organisms isolated significantly more frequently from affected than from control eyes, which suggests that these bacteria may be a cause of the conjunctivitis. All cultures for chlamydiae, M. hominis, Neisseria gonorrhoeae, and anaerobic bacteria were negative. The mother's race, social status, illness, and obstetric events were found to have no effect on the incidence, time of onset of conjunctivitis, or micro-organisms isolated. The clinical characteristics of conjunctivitis were also not related to the micro-organisms isolated. No potential pathogens were isolated from 63-5% of the eyes showing conjunctivitis. The results suggest that some of these cases may be caused by chemical irritation, and the possibility of an infectious aetiology is also discussed.

Growth and effect of chlamydiae in human and bovine oviduct organ cultures.

Organ cultures of 10 Fallopian tubes were inoculated with a genital strain of Chlamydia trachomatis and seven were infected. Infection was enhanced by centrifuging the organisms on to the tissues, larger numbers of organisms being reisolated from the tissues after this procedure. There was evidence of chlamydial multiplication because the number of organisms which were recovered from the tissues three to five days after inoculation had increased. Recovery was rare, however, after the sixth day, thus suggesting a self-limiting infection. Organ cultures of two bovine oviducts were infected with the bovine abortion strain of Chlamydia psittaci, but in these experiments centrifugation of the inocula did not enhance infection. The organisms were found in both the tissue and medium of cultures up to 18 days after inoculation and in much greater numbers than in the C. trachomatis-infected Fallopian cultures. Chlamydial infection was not entirely host-tissue specific, because C. trachomatis organisms were isolated from bovine oviduct cultures. Inclusions, however, were not detected histologically or electron microscopically in the epithelium of C. trachomatis-infected cultures, but they were detected by these means in C. psittaci-infected bovine cultures. All the elements of the chlamydial growth cycle were seen by electron microscopy, organisms being found in ciliated and possibly non-ciliated cells, and shedding of some infected epithelial cells was observed. No evidence of extensive epithelial cell damage was observed, however, and no loss of ciliary activity was detected in cultures infected with either C. trachomatis or C. psittaci when compared with uninoculated cultures. Thus acute salpingitis, when caused by chlamydial infection, is probably immunologically mediated.

Early detection of chlamydial inclusions combining the use of cycloheximide-treated McCoy cells and immunofluorescence staining.

Detection of Chlamydia trachomatis inclusions only 21 h after a specimen reaches the laboratory has been achieved by the combined use of cycloheximide-treated McCoy cells and immunofluorescence staining. Moreover, cells exposed to cycloheximide were more sensitive for detecting chlamydial inclusions than those pretreated by irradiation, since larger numbers of inclusions were found in the former cells. The application of this rapid and sensitive method allows a diagnosis of chlamydial infection to be made before antibiotic therapy is started. In this way, it should enable the treatment of nonspecific genital infections to be placed on a more rational basis.

Interaction of metargidin (ADAM-15) with alphavbeta3 and alpha5beta1 integrins on different haemopoietic cells.

Metargidin (ADAM-15) is a type I transmembrane glycoprotein belonging to the ADAM (A Disintegrin and Metalloprotease Domain) family of proteins and is widely expressed in different tissues and cell types. Members of this family contain an amino-terminal metalloprotease domain followed by a disintegrin domain, a cysteine-rich region and a membrane proximal EGF-like domain. The disintegrin domain of metargidin contains an RGD tripeptide sequence, suggesting that it may potentially interact with the integrin family of proteins. Here we identify integrin ligands for metargidin on haemopoietic cells, by using a chimeric protein containing the extracellular domain of metargidin fused to the Fc portion of human IgG. Binding activity to a panel of human cell lines was analysed by solid-phase cell-adhesion assays. Metargidin bound to a monocytic cell line, U937, and a T cell line, MOLT-4, in a specific manner. Adhesion was divalent cation- and temperature- dependent and strongly enhanced by Mn2+, all features of integrin-mediated binding. Using a panel of anti-integrin antibodies we show that alphavbeta3 is a ligand for metargidin on U937 cells. In contrast, for MOLT-4 cells, the integrin alpha5beta1 contributes to cell binding. Adhesion was mediated by the disintegrin domain of metargidin as RGD-based peptides inhibited cell binding to both cell lines. The specificity of the interaction between both alphavbeta3 and alpha5beta1 and metargidin was further confirmed by solid-phase adhesion assays using purified recombinant integrins. These results together indicate that metargidin can function as a cell adhesion molecule via interactions with alphavbeta3 and alpha5beta1 integrins.

Home-use nebulizers: a potential primary source of Burkholderia cepacia and other colistin-resistant, gram-negative bacteria in patients with cystic fibrosis.

Inhalation of aerosols contaminated with gram-negative bacteria generated from home-use nebulizers used by cystic fibrosis (CF) patients may be a primary route for bacterial colonization of the lung. Burkholderia cepacia was isolated from 3 of [corrected] 35 home-use nebulizers, and Stenotrophomonas maltophilia was isolated from 4 of 35 home-use nebulizers. Sputum cultures for two patients whose nebulizers were contaminated with B. cepacia did not yield the organism. However, DNA macrorestriction analysis by pulsed-field gel electrophoresis confirmed that one of two strains of B. cepacia recovered from the nebulizer of a third patient was also present in the sputum of that patient. Although Pseudomonas aeruginosa was isolated from 34 patients, none of the nebulizers were positive for the organism. Sixty-nine percent of nebulizers were contaminated, and up to 16 different environmental colistin-resistant, gram-negative species were identified. The heaviest contamination was found beneath the chamber atomizer. A questionnaire survey showed that the majority of patients (28 of 34) were receiving nebulized colistin and/or gentamicin. Patients who followed recommended instructions for good nebulizer hygienic practice and paid particular attention to drying had minimal or no contamination of their nebulizers.