TLR- and CXCR1-dependent innate immunity: insights into the genetics of urinary tract infections.

The susceptibility to urinary tract infection (UTI) is controlled by the innate immune response and Toll like receptors (TLRs) are the sentinels of this response. If productive, TLR4 signalling may initiate the symptomatic disease process. In the absence of TLR4 signalling the infected host instead develops an asymptomatic carrier state. The activation of mucosal TLR4 is also influenced by the properties of the infecting strain, and pathogens use their virulence factors to trigger 'pathogen-specific' TLR4 responses in the urinary tract but do not respond to the asymptomatic carrier strains in patients with asymptomatic bacteriuria (ABU). The TLR4 dependence has been demonstrated in mice and the relevance of low TLR4 function for protection for human disease was recently confirmed in children with asymptomatic bacteriuria, who expressed less TLR4 than age matched controls. Functional chemokines and functional chemokine receptors are crucial for neutrophil recruitment, and for the neutrophil dependent bacterial clearance. Interleukin (IL)-8 receptor deficient mice develop acute septic infections and chronic tissue damage, due to aberrant neutrophil function. This mechanism is relevant for human UTI as pyelonephritis prone children express low levels of the human CXCL8 (Il-8) receptor, CXC chemokine receptor 1 (CXCR1) and often have heterozygous CXCR1 polymorphisms. This review illustrates how intimately the innate response and the susceptibility to UTI are linked and sophisticated recognition mechanisms that rely on microbial virulence and on host TLR4 and CXCR1 signalling.

The host response to urinary tract infection.

The authors use the UTI model to identify basic mechanisms of disease pathogenesis, host response induction, and defense. Their studies hold the promise to provide a molecular and genetic explanation for susceptibility to UTI, and to offer more precise tools for diagnosis and therapy of these infections. There are few infections where the host response is understood in such detail and where pathologic host responses can be linked to distinct disease states. The susceptibility to UTI varies greatly in the population. The studies suggest that distinct molecular defects can cause the clinical entity of acute pyelonephritis with renal scarring, and suggest that the susceptibility to UTI in certain patient groups may have a genetic basis. In addition, the distinct signal transduction pathways explain the development of symptoms, and propose that defects in those signaling mechanisms may occur in patients with ABU. In the future, it may be useful to include these host response parameters in the diagnostic arsenal, to help in early detection of patients susceptible to recurrent UTI and renal scarring. These patients may then be offered therapies that strengthen their defense, and be offered close surveillance for recurrences and other complications.

The lived experiences of autonomous Angolan midwives working in midwifery-led, maternity units.

OBJECTIVE: to describe the lived experiences of autonomous midwives working in Angolan midwifery-led maternity units. DESIGN: a qualitative approach using semi-structured, audiotaped interviews, in Portugese. Data were analysed in a six-step process. SETTING: three midwifery-led maternity units in the most densely populated suburbs in the capital of Angola, Luanda. The average number of deliveries per unit was 2500 per year. PARTICIPANTS: 11 midwives from the three maternity units. FINDINGS: four main areas emerged: society/culture, significant others, personal self and professional self. Sub-areas, concepts and supporting statements were defined in each area. KEY CONCLUSIONS: the midwives served within a population living in rough circumstances but which maintained strong traditional roots. The midwives did not support homebirths, but did assist when needed. The midwives described their professional role as a 'calling', which was very independent. Cure, was considered more important than care, and strong emotions were expressed when discussing cases of failure. The partograph was viewed as an important instrument and continuous learning as crucial in their role as autonomous midwives. IMPLICATIONS FOR PRACTICE: the model of a midwifery-led delivery unit described in this study may be used in other countries facing the same problems as Angola. Difficulties concerning transfer should be seriously considered as well as adequate education for the midwives. A pre-requisite in order for peripheral maternity units to have any impact on maternal morbidity and mortality, is a well-organised first-referral level.

Escherichia coli-induced inducible nitric oxide synthase and cyclooxygenase expression in the mouse bladder and kidney.

BACKGROUND: The host response to urinary tract infection includes the production of different inflammatory mediators. We investigated the cellular localization and time course of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) expression in the mouse bladder and kidney after bacterial infection. METHODS: Experimental urinary tract infection in mice was established by intravesical inoculation of a clinical uropathogen Escherichia coli (E. coli) AD 110. Urine was collected at 6-, 12-, 24-, and 72-hours postinstillation, and the nitrite concentration was determined. The induction of iNOS and COX-2 was studied by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Nitrite levels in the urine had increased threefold at 6 and 12 hours postbacterial instillation. Bladders from mice instilled with AD 110, but not with phosphate-buffered saline, showed a large number of iNOS-- and COX-2--expressing inflammatory cells. The inflammatory cell activation peaked at 6 and 12 hours postinstillation and had vanished by 72 hours. iNOS expression was detected in some urothelial cells after 24 and 72 hours, but COX-2 expression was not detected. In the kidney, infection activated an iNOS and COX-2 response, as shown by immunoreactivity in inflammatory cells at all time points. A strong epithelial iNOS response was observed in the renal pelvis at 12, 24, and 72 hours postinstillation, but COX-2 was not detected. Enhanced tissue expression of iNOS and COX-2 after bacterial instillation was also demonstrated by RT-PCR. CONCLUSIONS: E. coli AD 110 induced expression of iNOS and COX-2 in the urinary tract. Inflammatory cells expressed both iNOS-and COX-2, but epithelial cells expressed only iNOS and with a later onset than in the inflammatory cells. This suggests that the epithelial iNOS response is not caused by direct bacterial activation, but more likely is by mediators involved in the inflammatory response.

Evaluation of an adapted model of the World Health Organization partograph used by Angolan midwives in a peripheral delivery unit.

OBJECTIVE: To study the impact of an educational intervention of midwives' use of the Angolan model of the World Health Organization's (WHO) partograph. SETTING: A peripheral delivery unit with approximately 1500 deliveries per year, run by eleven midwives in Luanda, Angola. DESIGN: The quasi-experimental, One-Group Pre-test-Post-test design was used in this study. Fifty partographs plotted with an initial dilatation < 8 cm were randomly selected from the first period of six month to form sample I, and another fifty from the second six-months period to form sample II. INTERVENTION: In-service education (theory and practice) performed by a team of midwives and an obstetrician. MEASUREMENTS AND FINDINGS: When comparing sample II with sample I, statistically significant improvements were found in seven of 10 measured variables. This indicates a positive effect of the educational intervention on a proper use of the partograph. Due to the small sample size, however, this study cannot evaluate action taken in relation to prolonged labour. IMPLICATIONS FOR PRACTICE: The in-service educational programme may be of use when introducing the WHO partograph in similar settings, and the findings of this study may indicate which parts of the programme need more emphasis. CONCLUSIONS: The midwives improved in general their documentation of the partograph. However, they tended to exceed established criteria for responsibilities at the peripheral delivery unit, a fact supported by an increased number of missed transfers. The study did not, however, answer the question why the midwives acted as they did in the referred cases.

Bacterial adherence and mucosal cytokine production.

1. Uropathogenic E. coli adhere to mucosal sites. 2. In the urinary tract, adherence is followed by inflammation, including a mucosal cytokine response. 3. Bacteria activate epithelial cells to secrete IL-6 and IL-8. IL-6 may cause the fever and acute phase response that accompany systemic urinary tract infections. IL-8 may function as a neutrophil chemoattractant. 4. E. coli up-regulate adhesion molecule expression on epithelial cell lines and neutrophil migration through epithelial cell monolayers. This process is inhibited by antibodies to CD18 and ICAM-1. 5. Cytokines released by nonepithelial cells (T cells and monocytes) modify the epithelial cell cytokine response to bacteria.

Falls in 84- to 85-year-old people living at home.

The present study is a part of the Swedish longitudinal population study "70-year-old people in Gothenburg". The aim of the present study was to analyse retrospectively incidence, circumstances, and consequences of falls during one year among 741 home-living people aged 84-85. A comparison of social and medical characteristics of fallers and non-fallers aged 85 was performed. Information was collected by interviews and clinical examinations. In 1986/1987, 732 home-living people (244 men and 488 women), aged 85 gave information about falls during the last year. Three hundred and one (41%), 97 men and 204 women, had fallen at least once during the last year, mainly indoors. No sex difference was found in incidence. The most dominant triggering causes of falls were stumbling, dizziness, and feebleness. In 80% of the falls an injury occurred, of which every fourth was a fracture. A multivariate regression procedure showed that dizziness, vertigo and unsteadiness, transient ischemic attacks, antidepressant drugs, and poor subjectively experienced health characterized the fallers. Mortality rate of those between 85 and 88 years of age showed no association with falls.

Accidents in the institutionalized elderly: injuries and consequences.

A total of 308 major and 519 minor accidents involving 588 patients occurred during one year at a somatic long-term care hospital and its associated nursing homes. In relation to the number of patients, the incidence of accidents was nearly three times higher in the nursing homes than in the hospital. The most prevalent injuries in female patients were fractures and hematomas, while open wounds were more frequent among male patients. Hip fractures were about as common in women as in men, while fractures of the extremities were three times more frequent in women. The majority of the accidents occurred during daytime, in the patient's room and in many cases soon after admission. Most of the injuries were caused by falls and in more than 90% no staff was present. Accidents were reported most frequently in October-December, and least often in July-September. Two thirds of the severely injured had to be transferred to an emergency hospital for surgery or other treatment. Patients who had had major accidents also had a higher mortality rate six months after the accidents as compared to a control group. The medical and functional consequences for the patients were considerable. Measures to reduce the number of accidents among geriatric patients are therefore urgently needed.

Role of streptococcal IgG Fc receptor in tissue deposition of IgG in rabbits immunized with Streptococcus pyogenes.

Induction of anti-IgG during hyperimmunization of rabbit with Streptococcus pyogenes (group A streptococci; GAS) was previously shown to require the presence of IgG Fc receptors (FcR) in the vaccine strain. In the present work, we examined whether streptococcal FcR activity might also be of importance for heart and kidney deposition of IgG, known to occur in poststreptococcal sequelae as well as during experimental immunization of animals. Each of three IgG-binding (GAS types M1, M12 and M22) and two non-binding (GAS type T27 and S. agalactiae (GBS) type Ia) streptococcal strains were used for intravenous immunization of rabbits during two periods of eight and six weeks, respectively, separated by an interval of one month. Before use, vaccine strains were treated with KSCN and carefully washed in order to remove any surface-bound immunoglobulins. No deaths occurred among injected rabbits. No tissue deposition was elicited by the GAS type T27 or the GBS strain. In contrast, the strains of types M1, M12 and M22 all induced deposits of IgG in kidney and heart tissue, beginning during the first immunization period. In two tested animals, receiving GAS of types M1 or M22, circulating immune complexes containing anti-IgG antibodies were also detected. Finally, serum autoantibodies reacting with preparations of heart and kidney, but not lung or liver, were demonstrated in each of six animals receiving M1 or M22, reaching maximum levels during reimmunization; such antibodies were not evoked by the two strains not binding IgG. Our results suggest that, in GAS with capacity for non-immune binding of IgG, triggering of anti-IgG acted to enhance tissue deposition of IgG or immune complexes in immunized rabbits. Furthermore tissue-specific antibodies were elicited only by the IgG-binding strains and occurred comparatively late during immunization, suggesting that those antibodies might have been triggered due to the exposition of hidden kidney and heart determinants.

Individual evaluation of accident risks at nursing homes.

The purpose of the study was to find a practical applicable method for estimating risk of accidents among nursing home patients by localizing specified risk factors and recording accidents during a period of one year. During 1987-January-15 to 1988-January-14, a total of 153 accidents happened to 23 men and 76 women among 335 admitted patients. The strongest accident predictors suggested by a logistic regression procedure were: impaired balance, walking with device or human assistance, drugs influencing the central nervous system, dizziness and poor night-time sleep. The conclusion is reached that it will probably be possible to reduce accidents in the institutionalized elderly by education of staff, identification of risk patients, individual nursing planning and measurements.

Accidents in the institutionalized elderly: a risk analysis.

Among a total of 4,862 admittances to a Swedish geriatric hospital and its associated nursing homes, 827 accidents occurred in 588 patients during one year. The purpose of the present study was to establish the direct causes of these accidents and to identify possible risk factors. Information was collected from medical records, interviews with patients and staff, examination of the mental and physical state of the patients, and through reconstruction of the accidents. The investigation embraced 270 patients with 308 major accidents (fractures, sprains, open wounds, concussions and injuries to ligaments), and 318 patients with 519 minor accidents (bruises, contusions, abrasions and minor burns). Injury-free patients with nearest lower bed number in relation to patients with major accidents formed a control group. Patients with previous injuries, balance disturbances, and polypharmacy were at high risk, and intrinsic factors such as dizziness and impaired balance proved to be more significant as direct causes for the occurrence of accidents than environmental factors. The estimated risk for a patient with all these risk factors to have an accident during one year was 94%.

Role of group A streptococcal IgG Fc-receptor in induction of anti-IgG by immunization in the rabbit.

Previous work has demonstrated that streptococcal IgG Fc-receptors (FcR) may trigger production of anti-IgG after immunization of rabbits with group A streptococci. This effect seemed dependent on in vitro binding of IgG, derived from the growth medium, to the vaccine strains. In the experiments presented here, IgG was eluted from streptococcal strains to be used for immunization of rabbits by 1 M KSCN and washing, a treatment which did not affect the capacity of the strains to bind newly added IgG. Using two IgG FcR-positive group A streptococcal strains (M-types 1 and 22) for intravenous immunization, anti-IgG was found in the sera of 26 out of 28 rabbits, examined 8 weeks after immunization. In contrast, anti-IgG was not induced in 16 rabbits receiving either group A, type T27 or group B, type Ia streptococci both of which lack surface FcR activity. Finally, immunization with purified streptococcal IgG FcR (0.35 mg, given subcutaneously combined with Freund's complete adjuvant and two weeks later intraconjunctivally without adjuvant) also induced anti-IgG. In all rabbits, anti-human rather than anti-rabbit IgG was detected. It is proposed that in vivo interaction between the bacterial FcR and rabbit IgG, resulting in conformation changes in IgG, is a prerequisite for the induction of anti-IgG. Thus, streptococcal triggering of anti-IgG, ascribable to IgG Fc-receptor activity and not requiring presence of foreign IgG, has been demonstrated in the rabbit.

beta-N-acetyl-D-glucosaminidase (NAGase) and lysozyme activity in human parotid and submandibular saliva.

beta-N-acetyl-D-glucosaminidase (NAGase) and lysozyme activity were studied in isolated parotid and submandibular saliva collected from five healthy individuals over a 3-wk period. During the first week, saliva samples were collected three times within one specified day (9 a.m., noon, 4 p.m.). Then for each of the following 2 wk, saliva was collected at 9 a.m. of the same day. NAGase activity was determined spectrophotometrically by using p-nitrophenyl-glycoside as substrate. Lysozyme activity was determined turbidimetrically by using Micrococcus lysodeikticus cells as substrate. NAGase and lysozyme were present in all samples of parotid and submandibular saliva. NAGase activity was generally higher in saliva samples collected in the morning and decreased during the day. There was considerable variation in NAGase activity and almost no variation in lysozyme activity in samples taken from the same person. NAGase activity was higher in parotid than in submandibular saliva while lysozyme activity was somewhat higher in submandibular saliva.

T15 group A streptococcal Fc receptor binds to the same location on IgG as staphylococcal protein A and IgG rheumatoid factors.

Previous work has shown that IgG rheumatoid factors (RF) bind to the C gamma 2-C gamma 3 interface region of human IgG in the same area that binds staphylococcal protein A (SPA). Group A, C, and G strains of Streptococci possess Fc receptors that bind to IgG but not to fragments containing only the C gamma 2 or C gamma 3 domains. This work describes the binding site location on human IgG for the binding of the isolated Fc receptor from the T15 strain of a Group A streptococcus and its relationship to the site that binds SPA and the IgG RF. The isolated T15 Fc receptor (T15) with a molecular mass of 29.5 kD inhibited the binding of IgG RF to IgG. The binding of T15 itself to IgG was strongly inhibited by SPA (42.0 kD) and its monovalent fragment D (7 kD). Human IgG fragments consisting of the C gamma 3 domains did not inhibit the binding of T15 to IgG, whereas those with both domains were effective inhibitors. T15 did not bind to rabbit IgG fragments consisting of either the C gamma 2 or C gamma 3 domains, but did bind to those with both domains. An IgG3 myeloma protein was a poor inhibitor and has been shown to bind poorly to the IgG RF. Most IgG3 myeloma proteins did not bind to SPA. The substitution of Arg and Phe for His 435 and Tyr 436 is responsible for the poor binding of IgG3 to SPA and to the IgG RF. Chemical modification of His or Tyr on IgG reduced its ability to inhibit the binding of T15 to IgG. Reversal of the chemical modifications with hydroxylamine resulted in near complete restoration of inhibitory capacity. This information, collectively, coupled with the known positions in space of the His and Tyr residues in the C gamma 2-C gamma 3 interface region, verified that both His 435 and Tyr 436, and possibly His 310 and 433, are involved. These residues are also involved in binding SPA and the IgG RF. These data therefore indicate that the T15 Group A Streptococcal Fc receptor binds to the same location on the Fc of IgG as SPA and the IgG RF. The biologic relevance of these similarities between bacterial cell wall Fc receptors and IgG RF are not yet apparent, but suggest that RF could bear the internal image of these bacterial structures.

Interaction between streptococcal IgG Fc receptors and human and rabbit IgG domains.

Groups A, C and G streptococci were tested for their ability to bind 125I-labelled fragments of human and rabbit IgG in order to localize their sites of interaction with IgG domains. Among the Group A streptococci, strains with IgG Fc receptors bound 85% of the added IgG Fc fragments in the test systems, whereas these strains showed practically no reactivity with F(ab')2, Facb (F(ab')2 + C gamma 2 domains) or pFc' (C gamma 3 domains). The Group C and Group G strains bound 48-100% of IgG Fc, but could also bind up to 36% of the added F(ab')2 in accordance with a previously described 'alternative' Fab reactivity. However, unlabelled IgG F(ab')2 or Facb showed no, or only slight, inhibitory capacity for the binding of 125I-labelled IgG Fc to the C and G strains. Collectively, these results indicate that Groups A, C and G streptococci require both the C gamma 2 and C gamma 3 domains for interaction with IgG, and most probably also bind in the interface region between the C gamma 2 and C gamma 3 domains as has been shown for staphylococcal protein A.

Binding of IgM rheumatoid factor to group A, C and G streptococci with IgG Fc receptors.

The possibility that IgM rheumatoid factors bind to streptococci was studied. Using a sequence of Sephadex G200 gel filtration, protein A-Sepharose CL-4B chromatography and preparatory electrophoresis, IgM was isolated from the sera of 2 patients with rheumatoid arthritis and then radiolabelled with 125I. There was significant binding of radiolabelled IgM to group-A streptococci types M1, M15 and M22, and to a group-C and a group-G strain, all expressing IgG Fc receptors, but none to Staphylococcus aureus, Escherichia coli or to 11 other strains of streptococci without IgG Fc receptors. The radiolabelled IgM was separated by affinity chromatography on a column containing human IgG. Types M1 and M15 bound the fraction retained on the column, whereas M22 bound both this fraction and the non-retained fraction. Commercial human IgG, even at high concentrations, did not inhibit binding. The binding reaction, which is perhaps triggered either by the IgM rheumatoid factor or by IgG complexed with rheumatoid factor, could be a useful tool for removal of anti-immunoglobulin from the blood of patients with rheumatoid arthritis.

Anti-immunoglobulins in experimental streptococcal immunization; relation to bacterial growth conditions and Fc-receptors.

Heat-killed group A streptococci of types M12 and M22 were used for intravenous immunization of 60 rabbits. Presence of Fc-receptors binding monomeric IgG in M22 and their absence in M12 has been demonstrated previously. The strains were cultured in either Todd-Hewitt broth supplemented with 10% horse serum (TH-H) or in IsoVitaleX, a synthetic medium, supplemented with 10% autologous rabbit serum (IV-R). A mortality rate of 38% was noted in the first-mentioned group whereas no mortality was observed in the second group. Sera were examined for agglutination of red blood cells coated with either human or rabbit IgG. Antisera to strains cultured in TH-H regularly displayed anti-IgG antibodies reacting with human as well as rabbit IgG; anti-rabbit IgG titres of anti-M22 sera were significantly higher than those of anti-M12. Antisera to strains grown in IV-R displayed high levels of antibodies reacting with human but not with rabbit IgG. The levels of anti-human IgG did not differ between anti-M12 and anti-M22 sera.

Catheter-free geriatric care. Routines and consequences for clinical infection, care and economy.

In a geriatric hospital the routines of one ward were modified with the intention of removing indwelling catheters from all patients admitted to the ward. A continence training programme had been designed during the preceding 6 months. A total of 124 patients were admitted with indwelling catheters during a period of 18 months. It was possible to remove the catheters in 117 of these. Patients and their relatives reacted favourably to catheter-free care. The attitude of ward staff also was positive. The overall nursing requirements did not increase. Antibiotic prescription was 90 per cent less than in the control wards. This difference was accounted for not only by a reduction in drugs used against urinary tract infections, but also by a lower consumption of agents mainly used in the treatment of septicaemia, bronchopneumonia and wound infection. The cost of laundry and of hygiene and storage articles, including catheters, absorbing pads and other incontinence aids was 46 per cent of that in the control wards. Four years later, 65 per cent and 72 per cent of the patients from the test and control wards respectively, had died. Of the surviving patients from the test ward 78 per cent were still catheter-free.

The genetic control of virulence in group A streptococci. III. Plasmid-induced "switch-off"--effect on some pathogenic properties.

Recently, we reported that conjugal transfer of plasmid pERL1, determining i.a. erythromycin resistance (Emr), into group A streptococci could trigger the expression of anti-phagocytic activity, adhesiveness, opacity factor and capacity to bind immunoglobulin Fc-parts and beta 2-microglobulin. In the present study, ethidium bromide treatment of Emr transconjugants allowed the selection of "cured", erythromycin sensitive (Ems) mutants. This procedure did not affect the expression of the abovementioned characteristics. However, when plasmid pERL1 was again transferred to two such mutants, the "secondary", Emr transconjugants obtained showed lack of each of these properties. Our experiments thus demonstrated a "switch-on" as well as a "switch-off" effect, exerted by the same plasmid, pERL1, on some major pathogenic properties of group A streptococci.