No abstract

SUMMARY Human milk, after storage and pastuerisation at 730C for 30 minutes at a milk bank, was found to have little surviving IgA, IgG, lactoferrin, lysozyme, and C3 complement. Accurate pasteurisation at 62-50C produced a loss of 23-7 % of the lysozyme, 56-8 % of the lactoferrin, 34 % of the IgG, but no loss of IgA. Storage by deep freezing at -20°C for 3 months produced no appreciable loss of lactoferrin, lysozyme, IgG, IgA, or C3.Human milk is thought by many paediatricians to be the best food for low birthweight infants (Davies et al., 1972). In England and Wales five large-scale human milk banks operate primarily for this purpose (Rolles, 1973) and most maternity units make some effort to collect milk for their special care babies. We question whether the final product after storage and processing has the same value for the preterm infant as feeding at the breast has for the mature one. Little is known of the best method of collection, storage, and processing of human milk and this paper is intended to draw attention to two aspects: the effect of heating and storing of human milk on its content of immunoglobulins and other antimicrobial factors. Antigen and monospecific antiserum. Lysozyme was prepared by the method of Jolles and Jolles (1967) and lactoferrin prepared from human milk as previously described (Ryley, 1972). Monospecific antiserum to ocl-antitrypsin, IgG, lactoferrin, and lysozyme was raised in rabbits (Ryley, 1972;Ryley and Brogan, 1973;Ryley et al., 1975). Antisera to C3 component of complement and IgA were obtained from Hoechst Pharmaceuticals, Hounslow, England. MethodsElectroimmunoassay. 2 I1 volumes of either raw or treated milk were analysed by an electroimmunoassay method against monospecific antiserum in 1 % agarose, or in the case of IgG 1 % ion agar as previously described (Ryley and Brogan, 1973). Dilution of a laboratory control serum standardised against both a Bebring human serum and plasma controls were used for the estimations of al-antitrypsin, C3, IgA, and IgG. Dilutions of 1 mg/ml solution of both lysozyme and lactoferrin antigens were used in their appropriate assay. All estimations were carried out on duplicate plates. ResultsRaw milk. Table 1 shows the results of assays on 25 random donations to the milk bank.

e Three clinical Pseudomonas aeruginosa isolates (WCH2677, WCH2813, and WCH2837) isolated from the Women's and Children's Hospital, Adelaide, Australia, produced a metallo-␤-lactamase (MBL)-positive Etest result. All isolates were PCR negative for known MBL genes. A gene bank was created, and an MBL gene, designated bla AIM-1 , was cloned and fully characterized. The encoded enzyme, AIM-1, is a group B3 MBL that has the highest level of identity to THIN-B and L1. It is chromosomal and flanked by two copies (one intact and one truncated) of an ISCR element, ISCR15. Southern hybridization studies indicated the movement of both ISCR15 and bla AIM-1 within the three different clinical isolates. AIM-1 hydrolyzes most ␤-lactams, with the exception of aztreonam and, to a lesser extent, ceftazidime; however, it possesses significantly higher k cat values for cefepime and carbapenems than most other MBLs. AIM-1 was the first mobile group B3 enzyme detected and signals further problems for already beleaguered antimicrobial regimes to treat serious P. aeruginosa and other Gram-negative infections.T he continuing increase in antibiotic resistance in Gram-negative bacteria is of concern, not least because of the increasing lack of therapeutic options available to treat infections caused principally by Pseudomonas aeruginosa and Acinetobacter baumannii (3,17,21). This phenomenon has been exacerbated by the dissemination of metallo-␤-lactamases (MBLs) that can confer resistance to nearly all ␤-lactams, with the exception of aztreonam (4,5,43).Like many resistance mechanisms, MBLs can be encoded by either genes ubiquitously carried on the chromosome or mobile genes (39). The latter genes now include the following subgroups: IMP (15), VIM (26), SPM-1 (36), GIM-1, SIM-1, KMH-1 (25), , and the recently described NDM-1 (44). So far, they all belong to MBL subgroup B1. MBL genes are often embedded in class 1 integrons and are carried as gene cassettes. It has also been shown that while many MBL genes are plasmid mediated, some are carried on the chromosome and can be associated with Tn21-like transposons or Tn402 transposons (30, 34). However, SPM-1 is not associated with a standard integron but is flanked by two genetic elements, designated ISCR4 (18). ISCR elements are IS91-like mobile elements and can potentially mobilize and duplicate bla SPM-1 via rolling-circle replication (33, 37).The B3 subgroup MBLs have hitherto been reported for environmental bacteria, only some of which can cause opportunistic infections. These include Stenotrophomonas maltophilia (L1) (42), Janthinobacterium lividum (THIN-B) (23), Chryseobacterium meningosepticum (GOB-1) (1), Legionella gormanii (FEZ-1) (2), Caulobacter crescentus (CAU-1) (10), CAR-1 from Erwinia carotovora (29), POM-1 (32), and the recently reported ISCR1-associated SMB-1 (38). The MBL genes carried by these environmental bacteria encode subgroup B3 MBLs that are not closely related to the mobile B1 members (43). They are often GC rich and 2 to 3 kDa larger than the B1 subgroup members...

(1975). Thorax, 30,[72][73][74][75][76][77][78][79]. Soluble proteins of bronchopulmonary secretions from patients with cystic fibrosis, asthma, and bronchitis. The concentrations of nine plasma proteins were determined by quantitative immunoelectrophoresis in sputum specimens from 29 patients with cystic fibrosis (CF) and from 24 patients with severe asthma and chronic bronchitis. The results suggested that the population of CF patients could be divided into two groups in spite of an absence of difference in clinical status between the groups. Average concentrations of seven plasma proteins in sputum of group I CF patients were identical with those in sputum of patients with bronchitis, but the average concentrations of six of these proteins in sputum from group II CF patients were higher than those in specimens from the bronchitic patients and were similar to corresponding concentrations in sputum from patients with asthma, all of whom were examined while in status asthmaticus. The average concentrations of 14 secretory proteins were the same in all sputum specimens whether or not they were produced by patients with cystic fibrosis, asthma or bronchitis.

Whole cells and lipopolysaccharides (LPSs) extracted fromBurkholderia cepacia, Pseudomonas aeruginosa,Stenotrophomonas maltophilia, and Escherichia coli were compared in their ability to stimulate tumor necrosis factor alpha (TNF-α) from the human monocyte cell line MonoMac-6.B. cepacia LPS, on a weight-for-weight basis, was found to have TNF-α-inducing activity similar to that of LPS from E. coli, which was approximately four- and eightfold greater than the activity of LPSs from P. aeruginosa and S. maltophilia, respectively. The LPS-stimulated TNF-α production from monocytes was found to be CD14 dependent. These results suggest that B. cepacia LPS might play a role in the pathogenesis of inflammatory lung disease in cystic fibrosis, and in some patients it might be responsible, at least in part, for the sepsis-like cepacia syndrome.