Developing a risk prediction model for 30-day unplanned hospitalization in patients receiving outpatient parenteral antimicrobial therapy.

OBJECTIVES: Outpatient parenteral antimicrobial therapy (OPAT) is increasingly used to treat a wide range of infections. However, there is risk of hospital readmissions. The study aim was to develop a prediction model for the risk of 30-day unplanned hospitalization in patients receiving OPAT. METHODS: Using a retrospective cohort design, we retrieved data on 1073 patients who received OPAT over 2 years (January 2015 to January 2017) at a large teaching hospital in Sheffield, UK. We developed a multivariable logistic regression model for 30-day unplanned hospitalization, assessed its discrimination and calibration abilities, and internally them validated using bootstrap resampling. RESULTS: The 30-day unplanned hospitalization rate was 11% (123/1073). The main indication for hospitalization was worsening or nonresponse of infection (52/123, 42%). The final regression model consisted of age (adjusted odds ratio (aOR), 1.18 per decade; 95% confidence interval (CI), 1.04-1.34), Charlson comorbidity score (aOR, 1.11 per unit increase; 95% CI, 1.00-1.23), prior hospitalizations in past 12 months (aOR, 1.30 per admission; 95% CI, 1.17-1.45), concurrent intravenous antimicrobial therapy (aOR, 1.89; 95% CI, 1.03-3.47) and endovascular infection (aOR, 3.51; 95% CI, 1.49-8.28). Mode of OPAT treatment was retained in the model as a confounder. The model had adequate concordance (c-statistic 0.72; 95% CI 0.67-0.77) and calibration (Hosmer-Lemeshow p 0.546; calibration slope 0.99; 95% CI 0.78-1.21), and low degree of optimism (bootstrap optimism corrected c-statistic, 0.70). CONCLUSIONS: We identified a set of six important predictors of unplanned hospitalization based on readily available data. The prediction model may help improve OPAT outcomes through better identification of high-risk patients and provision of tailored care.

Daily bread: a novel vehicle for dissemination and evaluation of psychological first aid for families exposed to armed conflict in Syria.

BACKGROUND: Risks to the mental health of children and families exposed to conflict in Syria are of such magnitude that research identifying how best to deliver psychological first aid is urgently required. This study tested the feasibility of a novel approach to large-scale distribution of information and data collection. METHODS: Routine humanitarian deliveries of bread by a bakery run by a non-governmental organisation (NGO) were used to distribute parenting information leaflets and questionnaires to adults looking after children in conflict zones inside Syria. Study materials were emailed to a project worker in Turkey. Leaflets and questionnaires requesting feedback were transported alongside supplies to a bakery in Syria, and then packed with flatbreads. Three thousand bread-packs were distributed, from three distribution points to which questionnaires were returned, and then taken to Turkey and dispatched to the UK. FINDINGS: Notwithstanding delays, 3000 leaflets and questionnaires were successfully distributed over 2 days. Questionnaire return yielded 1783 responses, a 59.5% return rate. Overall ratings of the usefulness of the leaflet were 1060 (59.5%) 'quite a lot' and 339 (19.0%) 'a great deal'. Content analysis was used to code 400 respondent comments. Four themes emerged; positive comments about the leaflet, suggestions for modifications, descriptions of children's needs and the value respondents placed on faith. INTERPRETATION: Findings indicate the willingness of NGO staff and volunteers to assist in research, the remarkable willingness of caregivers to respond and the value of brief advice. It demonstrates the scope for using existing humanitarian routes to distribute information and receive feedback even in high-risk settings.

Establishing the feasibility of assessing the mental health of children displaced by the Syrian conflict.

BACKGROUND: In the humanitarian crisis context of conflict zones, collecting data is essential for identifying and addressing the mental health needs of refugee children to avoid mass suffering. This study tested the feasibility of recruiting refugees caring for children and using established and brief parent-report questionnaires in a challenging context to collect mental health data on refugee children displaced by Syria's conflict. METHODS: Caregivers of 4-10-year olds attending primary schools run by non-governmental organisation (NGO) Generation Freedom in and near refugee camps on the Syrian-Turkish border were invited to complete the Pediatric Emotional Distress Scale (PEDS) and Strengths and Difficulties Questionnaire (SDQ). RESULTS: It was possible to reach 144 adult refugees caring for children with research participation information and use informed consent procedures. A total of 106 caregivers completed the questionnaires yielding a good return rate (74%). Eighty-two (77.4%) caregivers had complete data on the PEDS and 61 (57.5%) on the SDQ. Almost half (49%) of the children met the clinical cut-off for being anxious/withdrawn and 62% for being fearful rated using the PEDS and 45% for SDQ rated emotional symptoms. More than a third had clinical levels of behavioural problems on both scales. CONCLUSIONS: It proved feasible to collect child mental health data in challenging conditions in the context of the Syrian crisis with support from a local NGO providing humanitarian assistance. The PEDS performed better than the SDQ in this context. High levels of emotional distress and behavioural problems in children reiterate the urgent need for evidence-based psychosocial support.

Assessing the impact of short-term surgical education on practice: a retrospective study of the introduction of mesh for inguinal hernia repair in sub-Saharan Africa.

PURPOSE: Inguinal hernia repair is the most common general surgery operation performed globally. However, the adoption of tension-free hernia repair with mesh has been limited in low-income settings, largely due to a lack of technical training and resources. The present study evaluates the impact of a 2-day training course instructing use of polypropylene mesh for inguinal hernia repair on the practice patterns of sub-Saharan African physicians. METHODS: A surgical training course on tension-free mesh repair of hernias was provided to 16 physicians working in rural Ghanaian and Liberian hospitals. Three physicians were requested to prospectively record all their inguinal hernia surgeries, performed with or without mesh, during the 14-month period following the training. Demographic variables, diagnoses, and complications were collected by an independent data collector for mesh and non-mesh procedures. RESULTS: Surgery with mesh increased significantly following intervention, from near negligible levels prior to the training to 8.1 % of all inguinal hernia repairs afterwards. Mesh repair accounted for 90.8 % of recurrent hernia repairs and 2.9 % of primary hernia repairs after training. Overall complication rates between mesh and non-mesh procedures were not significantly different (p = 0.20). CONCLUSIONS: Three physicians who participated in an intensive education course were routinely using mesh for inguinal hernia repair 14 months after the training. This represents a significant change in practice pattern. Complication rates between patients who underwent inguinal hernia repairs with and without mesh were comparable. The present study provides evidence that short-term surgical training initiatives can have a substantial impact on local healthcare practice in resource-limited settings.

CD5-positive follicular lymphoma: prognostic significance of this aberrant marker?

Follicular lymphomas are the most common of the clinically indolent non-Hodgkin lymphomas. The immunophenotypic pattern of follicular lymphoma classically demonstrates the B-cell markers CD19, CD20, CD22, CD79a, surface immunoglobulin and CD10. The tumour cells are usually negative for CD5. We described two cases of CD5-positive follicular lymphoma. This finding has rarely been described. Our aim was to discuss two cases of CD5-positive follicular lymphoma and review the published literature on the significance of CD5 expression. Bone marrow biopsies showing involvement with follicular lymphoma at our institution over the past 34 months were evaluated for the presence of CD5 positivity by flow cytometry and immunohistochemistry. Two of eight cases (25%) of the follicular lymphomas with marrow involvement at our institution were found to be CD5-positive. Only 36 cases of CD5-positive follicular lymphoma have previously been described in the literature. The clinical and therapeutic significance of this remains uncertain. More research into such cases may establish whether the presence of this aberrant marker bears prognostic significance.

Physically active families - de-bunking the myth? A qualitative study of family participation in physical activity.

BACKGROUND: The benefits of physical activity for reducing obesity and related chronic diseases are well known. The need for more family-based interventions to increase physical activity is frequently cited in the literature; however, little is known about if and how families are physically active together, and what factors might influence family-based participation in regular physical activity. This study examined the types of activities (physical and sedentary) engaged in as a family and explored parents' perceptions of the importance, frequency, nature and barriers to family physical activity. METHODS: Semi-structured telephone interviews were conducted with 30 parents (26 female, four male) of 10- to 11-year-old schoolchildren who attended either low, middle or high socio-economic status schools in Bristol, UK. Interviews were transcribed verbatim, anonymized and analysed using conventional content analysis. RESULTS: The majority of parents rated family engagement in physical activity as important, and identified benefits such as increased parent-child communication, spending time together, enjoyment, enhanced mental health, weight control and physical fitness. Despite these benefits most parents reported their families did little or no physical activity together as a family unit during the week, and any activities performed together were usually sedentary in nature. They reported increased family physical activity on the weekends but rarely including the full family unit simultaneously. Parents in two-parent households commonly paired off with one or more children because of complexities of schedules. Commonly reported barriers were busy lifestyles, diverse ages and interests of children and adults, bad weather, and lack of access to facilities, transportation and money to support activities. CONCLUSIONS: Family-based interventions might be more effective if they are designed to accommodate the complex demands and needs of two-parent and single-parent families and provide affordable, diverse activities appealing to a wide range of interests.

Trends in incidence of pneumococcal disease before introduction of conjugate vaccine: South West England, 1996-2005.

Introduction of pneumococcal conjugate and polysaccharide vaccines into the United Kingdom's routine immunization programmes is expected to change the epidemiology of invasive pneumococcal disease (IPD). We have documented the epidemiology of IPD in an English region (South West) with high-quality surveillance data before these programmes were established. We analysed data on isolates of Streptococcus pneumoniae from blood and CSF between 1996 and 2005 from microbiology laboratories in the South West that were reported and/or referred for serotyping to the Health Protection Agency Centre for Infections. The mean annual incidence of IPD increased from 11.2/100 000 in 1996 to 13.6/100 000 in 2005 (P<0.04). After adjusting for annual blood-culture sampling rates in hospitals serving the same catchment populations, an increase in annual incidence of IPD was no longer observed (P=1.0). Variation in overall incidence between laboratories could also be explained by variation in blood culture rates. The proportion of disease caused by serotypes 6B, 9V and 14 decreased significantly (P=0.001, P=0.007, and P=0.027 respectively) whereas that caused by serotype 4, 7F and 1 increased (P=0.001, P=0.003, and P<0.001 respectively) between 2000 and 2005. The level of penicillin non-susceptibility and resistance to erythromycin remained stable (2% and 12% respectively). This study provides an important baseline to assess the impact of changing vaccination programmes on the epidemiology of IPD, thus informing future use of pneumococcal vaccines.

Role of ions in a crossed-field diode.

The effect of ions in a magnetically insulated crossed-field gap is studied using a single particle orbit model, shear flow model, and particle-in-cell simulation. It is found that, in general, the presence of ions in a crossed-field gap always increases the electrons' excursion toward the anode region, regardless of the location of the ions. Thus, the rate at which the electrons migrate toward the anode, which is a measure of the diode closure rate, is related to the rate at which ions are introduced into the crossed-field gap. This anode migration of electrons is unrelated to crossed-field ambipolar diffusion. The implications of these findings are explored, such as pulse shortening in relativistic magnetrons and bipolar flows in pulsed-power systems.

Evaluation of a diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b vaccine given concurrently with meningococcal group C conjugate vaccine at 2, 3 and 4 months of age.

BACKGROUND AND OBJECTIVE: In view of the possible introduction of diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b (DTaP-IPV-Hib, eg Pediacel) vaccine in the UK, a study of the immunogenicity of Pediacel when given with one of two different meningococcal group C conjugate (MCC) vaccines at 2, 3 and 4 months of age was conducted. METHODS: Randomised controlled study in 241 infants. RESULTS: Post vaccination, the proportion of infants with anti-polyribosylribitol phosphate (PRP) levels > or =0.15 microg/ml was 93.2% (95% confidence interval (CI) 86.6 to 96.7) in the Pediacel group compared with 100% (95% CI 96.4 to 100) in the diphtheria-tetanus-whole-cell pertussis-Haemophilus influenzae type b (DTwP-Hib) group. The anti-PRP response was lower in infants receiving either Pediacel or DTwP-Hib when these vaccines were given concomitantly with meningococcal group C conjugate with diphtheria-derived protein CRM(197) as conjugate protein (MCC-CRM) compared with meningococcal group C conjugate with tetanus toxoid as conjugate protein (MCC-TT). For group C meningococcus, the proportion of infants with serum bactericidal antibody (SBA) titre > or =1:8 in the Pediacel group was 99.0% compared with 100% in the DTwP-Hib group. The MCC SBA geometric mean titre (GMT) was lower in those receiving Pediacel with MCC-TT than in those receiving DTwP-Hib with MCC-TT, although all titres were well above the protective threshold. The MCC SBA GMT was similar in those receiving Pediacel and DTwP-Hib and MCC-CRM. Responses to all other vaccine components were equivalent in the two groups. CONCLUSIONS: Pediacel is immunogenic when given at 2, 3 and 4 months of age. Coadministration of MCC vaccine can influence the Hib response, and the MCC response to a tetanus conjugate can be influenced by the nature of the coadministered DTP-Hib vaccine.

Quality of in-hospital care for adults with acute bacterial meningitis: a national retrospective survey.

BACKGROUND: Most adults with bacterial meningitis and meningococcal septicaemia present to junior doctors who have limited experience of these conditions. In contrast to paediatric practice, data from industrialized countries with regard to current hospital management practice are lacking. AIM: To examine whether current practice meets recommended standards in hospital management of community-acquired bacterial meningitis and meningococcal septicaemia among adults. DESIGN: National audit of medical records. METHODS: We conducted a survey of all patients with acute bacterial meningitis and meningococcal septicaemia admitted to 18 randomly selected acute hospitals in England and Wales between 1 January 2000 and 31 December 2001. All stages of care, including pre-hospital management, initial hospital assessment, record keeping, and ongoing hospital and public health management, were assessed. RESULTS: We identified 212 cases of bacterial meningitis and meningococcal septicaemia; 190 cases remained in the final analysis. Clinical record keeping did not meet acceptable standards in 33% of cases. Parenteral antibiotics were given within 1 h of hospital arrival in 56% of cases, increasing to 79% among those with an initial differential diagnosis that included bacterial meningitis or meningococcal septicaemia. A full severity of illness assessment was made in 27%. The quality of clinical practice varied widely between hospitals. This was most pronounced in the timeliness of consultant review (p < 0.0005). DISCUSSION: The quality of adult clinical practice for bacterial meningitis and meningococcal septicaemia needs improvement. This study provides a tool for developing targeted interventions to improve quality of care and outcome among adults with life-threatening infections, both in the UK and in other countries.

Changing epidemiology of bacterial meningitis among adults in England and Wales 1991-2002.

We examined the epidemiology of community-acquired bacterial meningitis among adults in England and Wales between 1991 and 2002. Among 3169 cases, meningococcal infection was predominant among young adults and pneumococcal meningitis among older adults. Whilst infection due to most causes decreased, the incidence of tuberculous (TB) meningitis doubled over the 12 years. The mortality rate among meningococcal and pneumococcal infections fell from 0.45/10(5) to 0.31/10(5) (P=0.0001). This study demonstrates important changes in the epidemiology of bacterial meningitis among UK adults. Improvements in clinical management, childhood vaccination programmes and the re-emergence of tuberculosis are likely to be drivers of these changes.

How should general practitioners investigate suspected urinary tract infection? Variations in laboratory-confirmed bacteriuria in South West England.

We analysed by age and sex the inter-laboratory variation in submission rates and positivity rates of urine samples from primary care that were submitted to seven microbiology laboratories within the South West of England. There was an almost twofold difference between the lowest and highest submission and positivity rates across all sex and age groups. This could not be accounted for by differences in population, age mix or numbers of nursing home beds. Increased submission in children will increase diagnosis of urinary tract infection (UTI). In contrast, over-investigation in other age groups increases laboratory and primary care costs and, in the asymptomatic elderly, may lead to unnecessary antibiotic treatment. Continued education is needed in primary care to improve the management of urinary symptoms. Laboratory-based studies of UTI are likely to underestimate the true incidence of this infection substantially. Standardised protocols for urine specimen submission are essential for practices and laboratories participating in surveillance of UTI and antibiotic resistance. In our discussion we offer seven recommendations for improving UTI investigation in general practice.

Yellow fever vaccine: a successful vaccination of an immunocompromised patient.

We report on the successful vaccination of a patient, 21/2 yr after bone marrow transplantation for myeloma. He was not severely immunosupressed and responded to the yellow fever vaccine (17D, a live attenuated vaccine) without any adverse affects.

Prevalence of urinary catheterization in UK nursing homes.

A postal questionnaire survey was undertaken in registered nursing homes in three different health districts in England: Gloucestershire, North Staffordshire and Leeds. Nursing homes may be registered as general nursing or mental health homes. If homes also have provision for residential beds these are defined as dual registered homes. Overall, 9% (438/4900) of residents, with an equal male:female split, had urinary catheters. There was no significant difference in the overall urinary catheterization rate in the three districts (P=0.9). There was a wide range of urinary catheterization prevalence between homes, with some homes of all three categories having no catheterized residents and several with a prevalence of over 40%. The wide range of prevalence may be due to differences in residents' underlying medical conditions or to differences in attitudes towards urinary catheterization by nursing home staff. Almost all homes (114/124, 92%) stated they had an infection control policy, but 31% (38/124) did not have a written policy on urinary catheter care. In view of the potential for morbidity, infection control policies should include a section on the care of urinary catheters and this should form part of the continuing training of nursing home staff.

Genetic analysis of capsular status of meningococcal carrier isolates.

The meningococcal capsule is the primary virulence factor with systemic isolates requiring full expression of the capsule but with capability to down-regulate the capsule in order to invade. The meningococcal capsular operon is composed of a number of genes that are involved in capsular synthesis and transport. Differences in capsular synthesis genes may allow discrimination between meningococcal serogroups whereas absence of genes for either synthesis or transport imply that the meningococcus is unencapsulated. Although mechanisms such as slipped-strand mispairing and acquisition of insertion sequences have been demonstrated to be involved in regulation of capsular expression, few studies have addressed the mechanisms of capsular expression in carrier isolates. Following a community-based intervention programme for an outbreak of meningococcal disease, we collected meningococcal carrier isolates from the intervention area and control areas. We undertook genetic analysis of the capsular operon and the mechanisms of capsular regulation, together with an investigation of the potential of capsular genes to identify the genogroup of non-serogroupable isolates. Use of the siaD gene allowed the discrimination of 30/89 (34%) non-serogroupable isolates into B, C, W135 and Y with a siaA gene PCR permitting the characterization of a further 6 isolates whose capsules contained sialic acid. Slipped-strand mispairing was evident in only 4 of 13 genogroupable B isolates and the insertion sequence IS1301 was found in 2 of 36 siaA-positive isolates. Of 51 non-genogroupable isolates 25 (49%) were shown to be ctrA negative. There was a higher percentage of ctrA-positive isolates (P<0.001) amongst meningococcal strains obtained from those sampled in non-intervention schools than those sampled at intervention schools. The ctrA-negative isolates warrant further investigation of their genotypic organization since such avirulent strains may be important in conferring natural protection against invasive disease. We found that after mass antibiotic prophylaxis, recolonization occurs preferentially with non-pathogenic meningococcal strains. This as implications for assessment of the benefits of mass antibiotic and vaccination programmes for outbreak control. Previously expressed concerns of increased risk due to removal of protective ora may have been overstated.

Diagnosis of invasive pneumococcal infection by PCR amplification of Streptococcus pneumoniae genomic fragments in blood: a multi-centre comparative study.

The increasing interest in the prevention of pneumococcal disease by immunisation necessitates improved organism-specific surveillance. This is particularly the case with regard to the contribution of Streptococcus pneumoniae infection to community-acquired pneumonia where blood cultures are often negative and sputum culture results ambiguous. Examination by PCR of blood samples taken at hospital admission offers one possibility for such improvement. The sensitivity, specificity and convenience of three pneumolysin gene PCR assays were compared in a large study, using EDTA blood from 175 patients (95 with proven pneumococcal bacteraemia, 80 with bacteraemia due to other organisms). The assays used were a PCR-enzyme immunoassay, a hybridisation probe assay run on the Roche LightCycler and a hydrolysis probe (TaqMan) assay run on an ABI 7700. Overall samples from only 57% of patients with bacteraemic pneumococcal infection yielded a positive result in at least one assay. Individual sensitivities ranged from 45% (TaqMan/ABI) through 35% (PCR-EIA) to 21% (Hybridisation/LightCycler). Specificity (PCR negative in the 80 control patients) ranged from 97-100%. The TaqMan/ABI assay was run in two centres and concordance between results was 91.4%, discrepancies being associated with very weakly positive samples. Overall, the TaqMan/ABI was the most sensitive and convenient assay; however, this method does not appear to offer any significant improvement over conventional blood cultures and is unlikely to be sufficiently sensitive to confirm a pneumococcal aetiology for non-bacteraemic pneumococcal pneumonia. For the present, therefore, blood culture is the preferred option.

How do microbiology consultants undertake their jobs? A survey of consultant time and tasks in South West England.

AIMS: To measure the total consultant medical microbiologist (CMM) weekly workload, to identify time spent on different activities, and to differentiate those tasks that were viewed by a consensus of consultants as core activities from those that could be accorded a lower priority. METHODS: A self administered questionnaire completed by consultant medical microbiologists in the Public Health Laboratory Service South West Group. RESULTS: Reported hours worked by respondents ranged from 41 to 65 hours each week, excluding on call activities. Eleven of 20 respondents reported working in excess of 48 hours each week. There was no correlation between hours worked and laboratory workload as measured by numbers of specimens. Clinical liaison, result authorisation, infection control, and management activities took up most time. Working practices varied widely between individuals, partly reflecting their differing roles in the laboratory. A consensus was reached regarding the relative importance and priority of many regular CMM activities. CONCLUSIONS: Consultant microbiologists can identify, with consensus, both high and lower priority activities in their daily practice. If such clinical priorities can be more widely agreed across the profession, this would provide a rational approach to workload control.

Workload and stress in consultant medical microbiologists and virologists: a questionnaire survey.

AIMS: To document demography, changing workload patterns, job satisfaction, morale, and prevalence of stress and psychological morbidity among UK consultant medical microbiologists and virologists. METHOD: A questionnaire survey of all identified UK practising consultant medical microbiologists and virologists (n= 464). RESULTS: Among 367 respondents (79%), there were 33 virologists and at least 89 single handed consultants. Over half the respondents (58%) were working a 1 : 1 or 1 : 2 on call rota during the week and a similar proportion (51%) at weekends. Of all consultants (including those working part time), 56% were working more than 48 hours weekly. Working more than 48 hours weekly, and being on call 1 : 1 or 1 : 2 at weekends, were both independently associated with increased psychological morbidity. Those on call 1 : 1 or 1 : 2 at weekends were also more likely to have low or very low morale. Female consultants were more likely to have higher stress scores. More than half of the respondents (208 of 363; 57%) were making active financial provision to retire early, and 198 of 363 (55%) did not intend to work beyond the age of 60. CONCLUSIONS: The long hours worked by many consultant microbiologists and virologists are in breach of the European Working Time Directive and are associated with a higher degree of psychological morbidity. For most consultants, the frequency of on call commitments is demanding and job satisfaction and morale have deteriorated. Urgent action is needed, particularly to support those working more than 48 hours each week and those on call at weekends 1 : 1 or 1 : 2. However, a major expansion of the consultant establishment cannot be achieved rapidly, and will be slowed further if early retirements become more frequent.

IgG antibody subclass responses determined by immunoblot in infants' sera following vaccination with a meningococcal recombinant hexavalent PorA OMV vaccine.

The introduction of meningococcal serogroup C conjugate vaccines into the UK immunisation schedule has led to the decline of serogroup C disease in those vaccinated but there is no imminent vaccine solution for serogroup B disease. The PorA outer membrane protein (OMP) is a potential serogroup B vaccine candidate and an outer membrane vesicle (OMV) vaccine containing six different PorA OMPs (each representing a different serosubtype) has been evaluated in phase II trials with encouraging results. Little is known about the IgG subclass response to the various antigens contained within this vaccine. These responses are important due to the different half-lives and complement fixing abilities of these antibodies. In this study, immunoblotting was undertaken with infants' sera following either three or four doses of vaccine, and OMVs from six isogenic meningococcal strains differing only in their PorA serosubtype. Following either three or four doses of the vaccine, IgG(3) and IgG(1) subclass antibodies were induced to all six of the isogenic strains, although sera collected after four doses of vaccine showed stronger antibody levels. IgG(3) was found in more sera than IgG(1). For both sets of sera, the two isogenic strains expressing P1.5,2 and P1.5(c),10 induced stronger IgG subclass antibody responses than the other four meningococcal strains. The recombinant hexavalent PorA OMV vaccine stimulates both IgG(1) and IgG(3) subclass antibodies, the subclasses that are most effective in activating the complement system.