Midwifery and body fluid contamination.
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Biomedical subjects
Publications and source records attributed to C A Hart.
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Branhamella catarrhalis has been associated with exacerbations of chronic bronchitis and asthma in adults. To investigate the possible role of B. catarrhalis in asthma of early childhood, we took posterior pharyngeal swabs from 24 normal children, 20 well asthmatics, and 20 acutely wheezy asthmatics, all between 1 and 4 years of age. On culture, 33% of the normal children were colonized with B. catarrhalis; colonization rates in the well asthmatics (70%) and in the wheezy asthmatics (75%) were significantly higher than in normals. The nature of this association requires further study.
Forty-six of 52 (88.5%) enterohemorrhagic Escherichia coli (EHEC) strains screened carried a "common" plasmid of about 90 kb which encoded sequences homologous to the Inc F-IIA replicon. A similarly high incidence of Inc F-IIA plasmid-containing strains was observed in other groups of diarrheagenic E. coli, but not in random environmental coliform isolates. Enteropathogenic E. coli (EPEC) contain plasmids of similar properties and share a 23-kb DNA fragment with plasmids from EHEC. The common region encodes the F-IIA replication region and sequences homologous to the transfer operon of the Inc F-II plasmid R1. Sequence homology varied between plasmids isolated from different EHEC/EPEC strains with > 80% showing homology to the regions encoding the rep and par genes. Only 5% of plasmids from EHEC strains had intact sequences homologous to the DNA between these two regions, including the oriT site. Some plasmids with an apparently intact tra operon still failed to plaque F-pilus-specific phages. This is consistent with observations that the large plasmids of EHEC and EPEC are phenotypically nonconjugative. These results suggest that the large plasmids of EHEC/EPEC constitute a family of transfer-deficient Inc F-IIA plasmids with varying degrees of deletion in tra function. The evolutionary ramifications of this finding are considered.
This article describes the implementation of an interagency peer review group and formal review board for psychiatric consultation liaison nurses (PCLN) practicing in affiliated institutions. Peer group members enhance their skill levels, assure quality standards of practice, and implement system changes through peer collaboration and member feedback. The model assures quality PCLN practice, fosters member resilience, creates a counterbalance for PCLN role isolation, and provides professional empowerment. The authors also disclose the peer group members' struggle and resolution to implement the mandated task of the annual performance review through the process of the PCLN formal peer review board.
A total of 160 adult Malawians with epigastric pain for longer than 2 weeks was investigated by endoscopy and serologically for evidence of infection with Helicobacter pylori. The organism was demonstrated histologically and/or by culture in 141 (88%) patients. With histological means and/or culture as the 'gold standard', the histological technique was 100% sensitive while culture was only 81% sensitive. All isolates tested were sensitive to amoxycillin and tetracycline; 74% were resistant to metronidazole. Endoscopic findings were normal in 104 (65%) patients (86.5% H. pylori positive). Evidence of duodenal ulcer was found in 41 (25%) patients (95% H. pylori positive). Histologically, gastritis was common, severe gastritis being associated with increased colonisation by H. pylori. Two kinds of urease test were found to be 100% specific for the presence of H. pylori. The sensitivity of the serological test (Helico-G test) was 98% but its specificity was only 27%. These results provide important background information for planned therapeutic studies in patients with upper gastro-intestinal disease in Malawi.
An outbreak of salmonellosis in calves was monitored for persistence of Salmonella typhimurium excretion in faeces and the effect of treatment with apramycin. Prior to treatment apramycin-resistant Escherichia coli were present but all S. typhimurium isolates were sensitive. Following the treatment of six calves with apramycin, apramycin-resistant S. typhimurium were isolated from two treated calves and one untreated calf. Plasmid profiles of E. coli and S. typhimurium were compared and plasmids conferring resistance to apramycin and several other antibiotics were transferred by conjugation in vitro from calf E. coli and S. typhimurium isolates to E. coli K-12 and from E. coli to S. typhimurium. The plasmids conjugated with high frequency in vitro from E. coli to S. typhimurium, and hybridized to a DNA probe specific for the gene encoding aminoglycoside acetyltransferase 3-IV (AAC(3)-IV) which confers resistance to apramycin, gentamicin, netilmicin and tobramycin.
1. Colonic mucus is heavily sulphated and it is likely that this contributes considerably to its resistance to degradation by bacterial enzymes. The presence of a mucin-desulphating enzyme in faeces could therefore be very important in determining the rate of degradation of secreted mucus and hence the level of protection of the mucosa. 2. A novel assay for mucin sulphatase has been developed using biologically labelled human colonic [35S]sulphomucin as a substrate and a mucin sulphatase has been purified from faeces by sequential high-performance gel filtration and ion-exchange chromatography. 3. The mucin sulphatase has been shown to have a pH optimum of 4.5 and activity over the pH range 3-7. It has a pI of 4.0 and is inhibited by inorganic sulphate and phosphate. The purified enzyme preparation gave a single band on electrophoresis with a molecular mass of 15,000 Da. It has a Km of 41.9 mmol/l and a Vmax. of 1.17 katal/kg for glucose 6-sulphate. The enzyme was also shown to enhance fivefold the deglycosylation of [3H]glucosamine-labelled mucin by a faecal mucin glycosidase preparation. 4. Two bacteroides spp. isolated from normal human faeces, Bacteroides fragilis and B. thetaiotaomicron, were found to be producers of mucin-desulphating enzymes. 5. Mucin sulphatase is likely to be critical in determining the rate of enzymic degradation of secreted colonic mucin.
An Escherichia coli K-12 transformant carrying 96.5-kb plasmid pLV501 from enteropathogenic E. coli (EPEC) strain K798 is able to produce the same characteristic attaching-effacing lesions in a rabbit ileal biopsy explant model as its parent strain. Cloned EcoRI-SalI DNA restriction fragments from this plasmid failed to reproduce the attaching-effacing lesions, but one recombinant plasmid, pLV527, containing 4.5 kb of pLV501 DNA, conferred on E. coli DH1 transformants the ability to invade enterocytes in the rabbit explant model. DH1(pLV527) was also able to adhere to and invade HEp-2 cells. The relative invasive ability of DH1(pLV527) was quantified by recovery of internalized bacteria following gentamicin treatment of infected HEp-2 monolayers. DH1(pLV527) was 1,000-fold more invasive than DH1 carrying pBR322 or a recombinant plasmid which had no physiological effect on ileal biopsy explants but was less invasive than an enteroinvasive E. coli strain or a transformant carrying the cloned invasion genes of Shigella flexneri. Invasion by DH1(pLV501) could also be detected but occurred at a level 30 times lower than that by DH1(pLV527). Colony-hybridization of the pLV527 insert against a panel of 49 EPEC and related strains revealed that only 11 contained pLV527-hybridizing sequences; thus, the invasion determinant is not an essential component of the attachment-effacement pathogenic mechanism. One pLV527-hybridizing strain displayed both attachment-effacement and invasiveness in the rabbit ileal biopsy explant model. No significant hybridization was observed to non-EPEC invasive pathogenic enteric bacteria, indicating that the invasion determinant encoded on pLV527 is distinct from those used by these organisms.
Over a period of 33 months in a paediatric accident and emergency department, the clinical pattern and possible causes of vulvovaginitis were studied prospectively in 200 girls presenting with genital discharge, irritation, pain, or redness. The major causes were poor hygiene and threadworms. The suspicion of sexual abuse arose in a few girls but no organisms of sexually transmitted disease were found. Urinary symptoms were common but only 20 patients had a significant bacteriuria and 40 had sterile pyuria. Specific skin problems occurred in 28 cases. Simple measures to improve hygiene and treatment of threadworms gave effective relief. Genital irritation caused urinary symptoms with no clinical evidence of infection, and it is advised that antibiotic treatment should await urine culture. Specific skin problems require help from a dermatologist. The possibility of sexual abuse must be considered especially if the vulvovaginitis is persistent or recurrent after adequate treatment.
This study examines the effects of an enteropathogenic Escherichia coli on microvillar membrane proteins during organ culture of rabbit ileal explants. Explants maintained with enteropathogenic E coli showed brush border effacement affecting approximately 50% of enterocytes, and where enteropathogenic E coli were closely adherent to the enterocyte surface microvilli were apparently being shed as vesicles. The microvillar membrane enzymes alkaline phosphatase, aminopeptidase N and alpha-glucosidase were released into the culture medium during organ culture, and this process was significantly enhanced by enteropathogenic E coli. This increased loss of microvillar membrane enzymes into the culture medium was associated with decreased tissue activities of microvillar membrane enzymes in enteropathogenic E coli infected ileal explants compared with control. For aminopeptidase N in particular, however, total enzyme activities in the tissue plus culture medium were increased comparing enteropathogenic E coli with control, suggesting that there might be an increase in the rate of synthesis of certain microvillar membrane proteins. Reorientating sucrose density gradient centrifugation of culture medium showed that alkaline phosphatase, aminopeptidase N and alpha-glucosidase were predominantly associated with particles of peak modal density 1.19 g/ml in both groups, confirming that enteropathogenic E coli accelerate release of microvillar membrane enzymes as vesicles. Analytical fractionation of ileal explants showed that enteropathogenic E coli resulted in a loss of microvillar membrane enzyme activities from the main brush border peak of modal density 1.21 g/ml present in controls. The density of the remaining smaller and lighter peak increased from 1.19 g/ml to 1.23 g/ml after homogenisation in digitonin, confirming association of these proteins with cholesterol containing membranes and not endoplasmic reticulum. These findings suggest that enteropathogenic E. coli accelerate the normal shedding of microvillar membrane proteins as vesicles, and may stimulate a compensatory increase in microvillar membrane protein synthesis.
The ability of a variety of epithelial, embryonal, placental, and neuronal cells to express the CD4 antigen and to be infected by human immunodeficiency virus 1 (HIV-1) was examined. Only two (IMR-32 and HeLa-T4) expressed CD4 detectable by indirect immunofluorescence, and both were infectable by HIV-1. Two others, a human laryngeal carcinoma (HEp-2) and human colonic carcinoma (HT-29), did not express CD4 antigen but were infectable by HIV-1. Infection of the HEp-2 cells was detectable four months (and 20 serial passages) later. Infection of HEp-2 cells was not inhibited by anti CD4 monoclonal antibody but was by the lectin concanavalin A. These results suggest the presence of a receptor other than CD4 can be involved in HIV-1 infection.
Seventeen bovine and 56 porcine Escherichia coli isolates from cases of diarrhoea and from healthy animals were examined for DNA sequences homologous to the genes for verocytotoxins (VT), enterotoxins and human enterohaemorrhagic E coli/enteropathogenic E coli (EHEC EPEC) sequences. VT-1 was the most common toxin among the bovine isolates and VT-2 the most common in the porcine isolates. No isolates had homologous sequences to enteropathogenic adherence factor, but 71.2 per cent hybridised to the DNA probe encoding specific EHEC sequences, and 95.9 per cent showed homology with a 23 kb DNA fragment common to EHEC and EPEC plasmids.
Although epidemics of nosocomial Legionnaires' disease attract great attention, up to 30% of sporadic cases of hospital-acquired pneumonia are caused by legionellae. Legionellae are ubiquitous contaminants of potable water and can achieve high numbers in the hot-water systems of large buildings such as hospitals. They are present in the mains water supply in small numbers but are amplified considerably in the hospital's hot-water system. This is encouraged by water temperatures below 50 degrees C, areas of stagnation and sludge formation, the presence of amoebae and other bacteria and the materials used in the piping. Formation of aerosols from contaminated water is a major mode of spread of legionellae, but there is evidence to suggest that aspiration is also a mode of entry. Safe levels of legionellae in cooling towers have been defined, but not for hot-water systems. A combination of culture and antigen detection by immunofluorescence offer the best method for enumerating legionellae in environmental samples. Control involves a mixture of physical (heat, UV irradiation, sanitation) and chemical (hypochlorite, ozone) methods combined with good plumbing practice (e.g. arrangement of pumps and calorifiers, elimination of dead-legs). Adequate control can be costly and requires considerable attention to detail.
Twenty trials (17 controlled and three observational cohort studies) on selective decontamination of the digestive tract (SDD) have been undertaken to date. SDD is defined as a technique which aims to eradicate carriage of disease-causing microorganisms by means of lethal oropharyngeal and faecal antimicrobial concentrations. The SDD concept and the criteria for the choice of the antimicrobials used in the SDD programme are explained. Abolition of the carrier state is thought to provide clinical, bacteriological and epidemiological benefits. Infection-specific morbidity and mortality, emergence of antibiotic resistance and outbreaks are the main endpoints evaluated in this review. Of the 15 controlled studies that considered carriage, 14 demonstrated a significant reduction of Gram-negative bacillary (GNB) carriage. Severe infections, including pneumonia and septicaemia, caused by enterobacteria and pseudomonads have been virtually eliminated in these trials. Five of the 12 centres that evaluated mortality showed a significant decrease among patients who received SDD. Two recent trials describe the control of an outbreak with a multiresistant Klebsiella by SDD. There are three indications for the use of SDD so far: (i) in trauma patients; (ii) in certain elective surgical procedures including liver transplantation and oesophageal resection; and (iii) in control of outbreaks of ICU infection. Future lines of research may include a properly designed trial with mortality as endpoint and studies on the transfer of SDD from the ICU into the ward as part of prophylaxis in major surgery.
A prospective survey of children admitted with gastro-enteritis to the Nasser Children's Hospital, Gaza revealed that 19% were excreting cryptosporidium, a significantly (p less than 0.001) greater percentage than that (7%) observed in children admitted for other reasons. Detection of cryptosporidium decreased when the change from hot dry to colder wetter weather occurred. Although Salmonella spp were isolated more frequently than cryptosporidium in children with diarrhoea (20% of cases), there was no statistically significant association between excretion of Salmonella spp and gastro-enteritis. A follow-up study of a cohort of the children with cryptosporidiosis indicated that over three-quarters were dehydrated and all were below their expected weight-for-age. There was a statistically significant association between cryptosporidium gastro-enteritis and evidence of respiratory tract infection.
OBJECTIVE: To derive performance characteristics for the Glasgow Meningococcal Septicemia Prognostic Score (GMSPS). DESIGN: Retrospective case-note study. SETTING: Two children's hospitals with Regional Intensive Care Unit. PATIENTS: One hundred twenty-three children with proven meningococcal septicemia (some with concurrent meningitis) from January 1, 1977 to December 31, 1986. MEASUREMENTS AND MAIN RESULTS: All 14 children who died after arrival scored greater than or equal to 8 either on admission (n = 8) or afterward (n = 6). Of 109 survivors, five scored greater than or equal to 8 (two were postictal at the time of scoring). A GMSPS of greater than or equal to 10 at or after admission predicted death with sensitivity 100%, specificity 98%, and positive predictive value of 88%; for GMSPS of both greater than or equal to 8 or 9, the values were 100%, 95%, and 74%, respectively. CONCLUSIONS: The GMSPS is a rapid clinical score that performs well in identifying children with poor prognosis who might benefit from early intensive care. It should be studied prospectively and compared with other scoring systems.
A novel beta-lactamase enzyme produced by a strain of Pseudomonas paucimobilis is described. The enzyme differs from other recorded beta-lactamases from Gram-negative aerobic bacteria. It was constitutive, and had the characteristics of a penicillinase. One single band of beta-lactamase activity at pI 4.6 was seen on iso-electric focusing. The enzyme had a molecular mass of 30 kDa. The beta-lactamase was strongly inhibited by tazobactam, sulbactam and clavulanic acid but not by the thiol residue inhibitors p-chloromercuribenzoate and p-chloromercuriphenylsulphonic acid, or by metallo-enzyme inhibitors. Plasmid DNA was not demonstrable, suggesting that the enzyme was chromosomally encoded.
A self-regulating trace heating element was assessed for its ability to maintain a temperature of 50 degrees C in the mixer valve and dead-legs of a shower, and for its effect on legionellas colonizing the shower. The trace heating element maintained a temperature of 50 degrees C +/- 1.5 degrees C in dead-legs when the circulating hot water supply remained above 45 degrees C. Legionellas appeared in a trace heated dead-leg when the temperature of the dead-leg reached 45 degrees C and the hot water supply dropped below this temperature. Legionellas were eradicated or significantly reduced in sections of the shower where a temperature of 50 degrees C was consistently achieved. The mixer valve which was trace heated but not insulated remained colonized with Legionellas. Legionellas were found in shower water throughout the study.