Legionella pneumophila: monoclonal antibody typing of clinical and environmental isolates.

Forty-one clinical isolates of Legionella pneumophila from sporadic cases of legionella pneumonia were collected from laboratories throughout the United Kingdom and were compared with 300 routine environmental isolates using two panels of monoclonal antibodies, covering serogroups 1-10. Eighty-five per cent of the clinical isolates belonged to the subgroup Pontiac of serogroup 1, whilst only 13% of the environmental isolates did. Approximately half of the clinical isolates tested came from patients with a recent history of foreign travel, mainly to southern Europe.

Legionella pneumophila in a hospital water system following a nosocomial outbreak: prevalence, monoclonal antibody subgrouping and effect of control measures.

Swabs and water samples from a hospital water system were cultured for legionellae over an extended period. Legionella pneumophila serogroup 1, including outbreak associated strains, were isolated in small numbers from approximately 5% of these samples despite implementation of the current DHSS/Welsh Office regulations. No cases of nosocomial legionnaires' disease were proven during the study. Physical cleaning and chemical sterilization of taps, and replacement of washers with 'approved' brands did not eradicate the organisms. Eradication of legionellae in hospital water supplies appears to be unnecessary in preventing nosocomial legionnaires' disease provided the current DHSS/Welsh Office recommendations are implemented.

Immunohistological detection of Legionella pneumophila in lung sections.

Immunohistology was used for the detection of Legionella pneumophila serogroup I in necropsy tissue. Study of pneumonic lung from the recent Stafford outbreak has shown that this technique has a high sensitivity. A retrospective postmortem examination showed that L pneumophila serogroup 1 was an unusual cause of pneumonia in Oxfordshire during the study period. L pneumophila serogroup 1 can be successfully subgrouped, using a panel of monoclonal antibodies on formalin fixed paraffin embedded sections. Immunohistological methods have a potentially useful role in the diagnosis of Legionellosis at postmortem examination and in the epidemiological investigation of individual cases and outbreaks.

Epidemiological studies using monoclonal antibodies to Legionella pneumophila serogroup 1.

Legionella pneumophila serogroup 1 can be subgrouped by panels of monoclonal antibodies. The Oxford panel divides serogroup 1 strains into three major subgroups, provisionally named Pontiac, Olda and Bellingham. Strains causing outbreaks tend to be in the Pontiac subgroup, with strains from the other subgroups appearing also in sporadic cases. Isolates from sources in the UK unassociated with outbreaks are mainly the Olda and Bellingham strains; only 10% are Pontiac, yet this strain has caused 80 to 90% of the cases of Legionnaires' Disease so far studied. We compared our method with other methods of subgrouping serogroup 1 strains.

Paleoepidemiologic investigation of Legionnaires disease at Wadsworth Veterans Administration Hospital by using three typing methods for comparison of legionellae from clinical and environmental sources.

Multilocus enzyme electrophoresis, monoclonal antibody typing for Legionella pneumophila serogroup 1, and plasmid analysis were used to type 89 L. pneumophila strains isolated from nosocomial cases of Legionnaires disease at the Veterans Administration Wadsworth Medical Center (VAWMC) and from the hospital environment. Twelve L. pneumophila clinical isolates, obtained from patients at non-VAWMC hospitals, were also typed by the same methods to determine typing specificity. Seventy-nine percent of 33 VAWMC L. pneumophila serogroup 1 clinical isolates and 70% of 23 environmental isolates were found in only one of the five monoclonal subgroups. Similar clustering was found for the other two typing methods, with excellent correlation between all methods. Enzyme electrophoretic typing divided the isolates into the greatest number of distinct groups, resulting in the identification of 10 different L. pneumophila types and 5 types not belonging to L. pneumophila, which probably constitute an undescribed Legionella species; 7 clinical and 34 environmental VAWMC isolates and 2 non-VAWMC clinical isolates were found to be members of the new species. Twelve different plasmid patterns were found; 95% of VAWMC clinical isolates contained plasmids. Major VAWMC epidemic-bacterial types were common in the hospital potable-water distribution system and cooling towers. Strains of L. pneumophila which persisted after disinfection of contaminated environmental sites were of a different type from the prechlorination strains. All three typing methods were useful in the epidemiologic analysis of the VAWMC outbreak.

Development of a standardized subgrouping scheme for Legionella pneumophila serogroup 1 using monoclonal antibodies.

A panel of monoclonal antibodies to Legionella pneumophila serogroup 1 and a subclassification scheme were developed in a collaborative project among three laboratories. The seven most useful monoclonal antibodies were selected from three previously developed panels on the basis of indirect fluorescent antibody patterns with 83 strains of L. pneumophila serogroup 1 that were obtained from widely distributed geographic locations. The isolates were divided into 10 major subgroups on the basis of reactivity patterns that can be readily reproduced in any laboratory and are not subject to major inconsistencies of interpretation of staining intensity. A standard protocol for the indirect fluorescent antibody procedure was also developed.

Legionella pneumophila serogroup 1 subgrouping by monoclonal antibodies--an epidemiological tool.

A panel of 10 monoclonal antibodies was used to subgroup 326 strains of Legionella pneumophila serogroup 1. All but two strains could be classified into three major subgroups named after their representative strains Pontiac 1, Olda and Bellingham 1. Of the 50 isolates from patients, 44 representing 32 separate incidents were of the Pontiac subgroup. This subgroup was also found in 16 of 18 buildings epidemiologically associated with Legionnaires' Disease. In contrast, strains of the Olda subgroup predominated in buildings where no infections had occurred. In 9 of the 11 incidents where isolates were available from at least one patient as well as from the suspected environmental source, the monoclonal antibody reaction patterns of strains from patients were identical to those of one or more of their environmental counterparts.

Rubella in the United Kingdom, 1970-1983.

The numbers of acquired and congenital rubella infections in the United Kingdom were obtained from clinical and laboratory reports and from notifications to the National Congenital Rubella Surveillance Programme. Since 1970 the annual frequency of clinical infection has varied from 150 to 450 cases per 100,000 population and laboratory reports of infection, from 800 to 4,100 per year. The number of notified congenital rubella infections varied from 12 to 86 per year. The largest recent epidemics occurred in 1978 and 1979, with an increase in the number of congenital rubella infections during the following winters. Increased numbers of cases occurred every one to three years, with troughs of two to three years, but peaks in different localities often did not coincide. Terminations of pregnancy associated with rubella or rubella vaccination during pregnancy are reported by the Office of Population Censuses and Surveys and vary with the incidence of acquired rubella; a maximum of 830 abortions were performed in 1978 for women who acquired the disease, and from 27 to 156 were performed each year for women vaccinated just before or soon after becoming pregnant. The effect of the vaccination program is discussed in relation to the decrease in the number of young women without rubella antibody.

Antibody to cytomegalovirus in Malta.

Antibody to cytomegalovirus (CMV) was sought in sera from Malta using immunofluorescence. Seven per cent of the infants, 36% of the school children, increasing to 100% of the adults aged over 40 years were found to have antibody. Most infection occurred in pre-school children and adults over 25 years of age. This pattern of antibody acquisition appears different from that described for other countries.

Investigation and control of an outbreaks of legionnaires' disease in a district general hospital.

Between December, 1979, and July, 1980, 12 cases of legionnaires' disease were recognised in a district general hospital. 11 of the patients probably acquired their infection within the hospital. Epidemiological and environmental studies indicated that the plumbing system and possibly also the air-conditioning cooling-tower exhaust in the new building of the hospital were the sources of infection. Chlorination of the cold-water supply and raising the hot-water temperature appeared to terminate the outbreak.

Isolation of Legionella pneumophila from water systems: methods and preliminary results.

A preliminary survey of water systems in hospitals and hotels showed that Legionella pneumophila may be found in water storage and distribution systems as well as in the recirculating cooling water of air-conditioning plants. Altogether 42 isolates of L pneumophila were made from 31 establishments, six of which were associated with cases of legionnaires' disease but in 25 of which there was no known association with disease. In the six establishments implicated epidemiologically as the source of legionnaires' disease, these organisms were found in each of their water-distribution systems and also in the cooling water from each of the three with cooling towers. In establishments not associated with cases, water from three out of nine cooling towers, four out of 24 taps or showers, and one out of 15 storage tanks was found to contain legionellae. The organisms were isolated by guinea-pig inoculation and subsequent culture of their peritoneal fluid, liver, and spleen. Finding L pneumophila in water systems in the absence of cases of legionnaires' disease should not at present be an indication for attempts at eradication.

Examination for influenza IgA and IgM antibodies in pregnancies associated with fetal neural-tube defects.

Early antenatal serum specimens were collected from 25 women who subsequently gave birth to infants with anencephaly or spina bifida. Fluorescent-antibody test for influenza-specific IgA and IgM antibodies, although shown to be reliable for the detection of recent influenzal infection, failed to demonstrate such infection in any of these women. Early infection was detected in one of 50 control women who gave birth to a healthy infant. The results indicate that influenzal infection in pregnancy was not a major cause of neural-tubal defects in Oxford during 1972--76, if a cause at all.

Legionnaires' disease in a transplant unit: isolation of the causative agent from shower baths.

Legionnaires' disease was diagnosed in two patients in a transplant unit, both patients having occupied the same postoperative cubicle shortly before onset of their illnesses. Legionella pneumophila was found in water taken from the cubicle shower bath and from other showers in the unit. To eradicate the legionellae, the water supply was treated with chlorine, but this had only a temporary effect.

The effects of viral infections on renal transplants and their recipients.

A prospective study of viral infections occurring after 188 renal transplants in 167 patients showed active cytomegalovirus (CMV) infection after 52 per cent of transplantations. All 37 CMV seronegative cases who received grafts from seronegative donors remained free of infection, while 24 (70.6 per cent) of 34 seronegative recipients whose donors were seropositive developed primary CMV infection (p less than 0.001). The diagnosis of 92 per cent of these primary infections was made between one and two months after grafting. Secondary CMV infection was found in 71 (62 per cent) of 114 seropositive cases, and the frequency of infection was not affected by the CMV status of the renal donor. Neither acute rejection episodes nor total graft rejections were associated with primary or secondary infections. CMV was isolated from a colonic abscess and the relationship of the virus to the intestinal disease is discussed. Herpes simplex virus was isolated from 47 per cent of cases and 32 per cent had an increase in antibody titre. Zoster was seen in nine patients, representing an incidence of 3.4 per cent per year. Other viral or mycoplasmal infections diagnosed included 71 due to respiratory tract pathogens, and a single case of hepatitis B. None of these infections was particularly severe or frequent and no association with graft rejection was detected.

The antibody response in Legionnaires' disease.

From 22 patients with Legionnaires' disease, 86 sera were examined for specific serotype 1 IgM and IgG antibodies by the indirect immunofluorescence technique. No antibody was detectable until 8 days or more from the onset of symptoms. When produced the amount was widely variable and remained detectable for periods from less than 34 days to more than 1 year. Intially IgM antibody predominated, ten patients produced only IgM in the first 21 days, six produced only IgM in the first 28 days and three did not produce IgG at any time. One patient, and possibly a second, produced only IgG antibody. Since IgM antibody was still present in one patient after a year it is important not to accept the presence of this as evidence of very recent infection. It is advisable that any type of serological test for L. pneumophila infection should detect the production of both IgM and IgG antibodies.

Cytomegalovirus and blood transfusion in neonates.

A fatal case of neonatal cytomegalovirus (CMV) infection attributed to exchange transfusion is described. The incidence of CMV transmission by exchange and other neonatal transfusion was studied, and the use of CMV antibody-free blood for these procedures was shown to be effective in preventing CMV infection in neonates.