High Staphylococcus hyicus colonization rates were found in vaginal samples of healthy breeding sows and in skin samples of their offspring. Twenty-two different phage types were identified among the 720 isolates of S. hyicus examined. Two to 13 different phage types were isolated per herd. Phage typing, as well as characterization of about 10% of the isolates by plasmid profiles and antibiogram patterns, showed that, several different clones of S. hyicus could be present simultaneously in vagina of gilts and also on skin of piglets. Generally isolates from the vagina of one animal were identical as regards to phage types, plasmid profiles, and antibiogram patterns during the entire investigation period. Isolates from the skin of piglets were of the same type as their mothers, indicating that vertical transmission had taken place. S. hyicus strains isolated from the skin of piglets within 24 h after birth were identical to strains isolated 3 weeks after birth from the same litter, indicating that the vaginal strains became part of a stable skin flora.

Calculations have been carried out which suggest that as few as 6 × 104 molecules of anti-poliovirus antibody per millilitre of serum may be sufficient to prevent the clinical disease under certain epidemic conditions. Other calculations have been made involving therapy of the experimental disease in monkeys and certain factors required for successful serum therapy have been discussed.

Japanese encephalitis (JE) is a serious health problem in the southwestern region of Nepal. Serological diagnostic kits for routine diagnostic use in this region have not been available. This study was performed to examine if the particle agglutination (PA) assay for Japanese encephalitis virus (JEV) IgM could be applicable to the samples collected in Nepal and also to evaluate the accuracy of clinical diagnosis of JE. One hundred and ninety-three blood samples were collected from the patients clinically diagnosed with JE or other infectious diseases in the JE-endemic, southwestern region of Nepal, in 2000. The PA assay was performed on these 193 serum samples and the results were compared with those by IgM-capture ELISA. Eighty-six samples were IgM-positive by the PA assay, and 71 of 86 were also positive by IgM-capture ELISA (sensitivity, 99%; specificity, 88%; positive predictive value, 0·82; negative predictive value, 0·99). These results suggest that the PA assay is a simple, reliable and useful diagnostic test to support clinical diagnosis in rural hospitals of Asia including Nepal.

1. Several strains of the influenza bacillus were grown under varying conditions for many months in order to ascertain whether morphology and colonial appearances could be permanently modified.

2. It was found that a modification in morphology occurred in all the strains studied.

3. Typical coccobacillary forms were changed to atypical long-curved forms.

4. The reverse change from atypical was also observed but was not so frequent, nor, when it occurred, was it so constant.

5. The change took place most readily after growth in a flask of Fildes' broth for several weeks or months at 37° C.

6. There was found to be a definite association between morphology and colonial form. The typical strains produced smooth colonies, while the atypical gave rough colonies, or colonies very much smaller than those produced by the typical.

7. When the change in morphology took place the change in colonial form occurred at the same time.

8. The biochemical characters remained on the whole unchanged.

9. One hundred and forty strains were examined for their fermentation reactions. The sugars most frequently fermented were dextrose, maltose and sucrose.

10. The atypicals were more active fermenters than the typicals.

11. 63·9 per cent. of the typicals, and 18 per cent. of the atypicals, gave a positive indol reaction.

12. Although the ability to grow on X or V alone affords an important differential criterion within this group, great care is necessary in interpreting the results obtained, especially in the case of those strains which grow on V in the absence of X. Different yeast preparations may give very different results in this respect.

13. All the strains tested were non-haemolytic.

In April 2020, Belgium experienced high numbers of fatal COVID-19 cases among nursing home (NH) residents. In response, a mass testing campaign was organised testing all NH residents and staff. We analysed the data of Flemish NHs to identify institutional factors associated with increased SARS-CoV-2 infection rates among NH residents. Cross-sectional study was conducted between 8 April and 15 May 2020. Data collected included demographics, group category (i.e. staff or resident), symptom status and test result. We retrieved additional data: number of beds and staff, type of beds (level of dependency of residents) and ownership (public, private for profit/non-profit institutions). Risk factor analysis was performed using negative binomial regression. In total, 695 NHs were included, 282 (41%) had at least one resident tested positive. Higher infection rate among residents was associated with a higher fraction of RVT beds, generally occupied by more dependent residents (incidence rate ratio (IRR) 1.97; 95% CI 1.00–3.86) and higher staff infection rate (IRR 1.89; 95% CI 1.68–2.12). No relationship was found between other investigated NH characteristics and infection rate among residents. Staff-resident interactions are key in SARS-CoV-2 transmission dynamics. Vaccination, regular staff testing, assessment of infection prevention and control strategies in all NHs are needed to face future SARS-CoV-2 epidemics in these settings.

This paper is written from the practical point of view of a laboratory worker who is daily in direct contact with the cases submitted to him for diagnosis. Its purpose is to prove the inefficiency of the Widal reaction as a diagnostic test, and to urge its replacement by a more satisfactory method. Such a method is to be found in the application of the discoveries and theories on agglutination of Weil and Felix (1920), Felix (1924 and 1929), and Felix and Olitzki (1928 and 1929).

Community-acquired Staphylococcus aureus infections are a public health concern, yet little is known about infections that do not present to hospital. We identified community-onset S. aureus infections via specimens submitted to a community-based pathology service. Referring doctors confirmed eligibility and described infection site, severity and treatment. Isolates were characterized on antibiotic resistance, PFGE, MLST/SCCmec, and Panton–Valentine leukocidin (PVL), representing 106 community-onset infections; 34 non-multiresistant methicillin-resistant S. aureus (nmMRSA) (resistant to <3 non-β-lactam antibiotics), 15 multiply antibiotic-resistant MRSA (mMRSA) and 57 methicillin-sensitive S. aureus (MSSA). Most (93%) were skin and soft tissue infections. PVL genes were carried by 42% of nmMRSA isolates [95% confidence interval (CI) 26–61] and 15% of MSSA (95% CI 8–28). PVL was associated with infections of the trunk, head or neck (56·4% vs. 24·3%, P = 0·005) in younger patients (23 vs. 52 years, P < 0·001), and with boils or abscesses (OR 8·67, 95% CI 2·9–26·2), suggesting underlying differences in exposure and/or pathogenesis.

This study aimed to evaluate the incidence of Staphylococcus aureus infections in different departments of Belcolle Hospital in Viterbo and the surrounding area between January 2003 and June 2008. Isolates of methicillin-resistant S. aureus (MRSA) recovered in this time interval were characterized by microbiological and molecular methods to evaluate the reliability of simple criteria to distinguish between hospital-acquired and community-acquired isolates. MRSA accounted for 33% of all S. aureus, with a significantly higher prevalence in isolates from nosocomial infections. MRSA isolates were assayed by PCR for the presence of 13 genes associated with virulence, agr type and SCCmec type. Cumulative data were analysed by partial least square discriminant analysis and a clear correlation was demonstrated between genetic profiles and classification of isolates as hospital or community acquired according to simple temporal criteria. Nosocomial MRSA isolates from blood samples showed significantly higher genetic diversity than other nosocomial isolates. Our data confirm the existence of significant differences between community- and hospital-acquired MRSA isolates.

We describe and analyse an outbreak of measles that affected Belgium early 2017. In total, 289 cases were reported, mostly (53%) in people 15 years or older. For 133 (46%) vaccination status was unknown and a further 117 (41%) were not vaccinated. According to national guidelines, 83 of the unvaccinated cases (29% of total cases) should have received minimum one dose of vaccine, but did not. One in five cases (21%) did not present with the classical triad of fever, rash and any of coryza, conjunctivitis or cough. Rash was the most sensitive symptom, being absent in only six cases. A large proportion of cases (125/289, 43%) required hospitalisation. In hospitalised patients, the most commonly observed complications were hepatic disorders (present in 58/125 hospitalised patients, 46%). Thirty-six of the cases (12%) were in healthcare workers and nosocomial spread contributed importantly to the outbreak. Older age at presentation, altered clinical presentations and presence of complications like hepatitis can delay the correct diagnosis of measles. Clinicians should maintain a high index of suspicion in any individual presenting with rash. If the elimination target is to be reached, catch-up vaccination campaigns should be intensified and target young adults and health care workers.

No evidence of vaccine virus transmission was found in two studies where Wistar RA 27/3 rubella vaccine was administered intranasally. Vaccine was immunogenic in all of 23 vaccinated children in one study, while in the other only 5 of the 11 vaccinees developed antibody. The reduced seroconversion rate in the latter study appears to have been caused by one or a combination of factors, including the vaccination technique, the presence of infective nasal conditions in vaccinees and the titre of vaccine used.

A report is given of a milk epidemic of scarlatinal angina, comprising 118 cases of scarlet fever and about fifty cases of sore throat.

The infection was spread through contamination of the milk from a milkmaid with purulent otitis media after non-recognized scarlet fever.

On cultivation, Streptococcus pyrogenes, group A (Lancefield), type 3 (Griffith) was isolated from 108 of these patients and from pus from the ear of the milkmaid. The cows, on the other hand, and their milk were found to be normal (two examinations at an interval of 6 days).

Inquiry into the conditions under which the milk was transported from the producer via the dairy to the consumers and information concerning the distribution and consumption of the milk confirmed in all details the assumption as to the causal connexion between the otitis media in the milkmaid and the outbreak of the epidemic.

This epidemic furnishes an example of transmission of the infection from man directly through the milk to a fairly large number of consumers without any intermediate infection (mastitis) in the cows.

Clinically the cases in this epidemic may be said, on the whole, to be mild; still, one of the patients died of complicating bronchopneumonia.

Neutralization and complement-fixation tests to detect rubella antibody are described. Results of such tests show that between 80 and 95% of adults in England and Wales have neutralizing antibody. The presence of complement-fixing antibody indicates recent infection with rubella virus.

Results are presented showing the development of neutralizing and complement-fixing antibody after rubella.

Antibody tests on children with congenital rubella and their mothers are detailed. It is noted that higher neutralizing antibody titres are found in this group than in the general population.

(1) A collection of S. typhi-murium strains, isolated during 11 months, in or near Manchester, was examined for the presence of symbiotic bacteriophage. In all, 177 strains derived from eighty-three incidents were investigated.

2. The different phages, or combinations of phage, allowed these strains to be divided into eleven varieties. Three hitherto undescribed types of phage were discovered.

3. With two minor exceptions, all groups of strains isolated from associated cases of infection carried the same type of phage, so that the ‘typing’ was in agreement with epidemiological expectations. In the two exceptions, the relationship of the cases was not intimate, and infection from different sources was an obvious possibility.

4. It is concluded that this is a reliable method of typing. It is probably applicable to other groups of bacteria. Its value would be enhanced by the discovery of a simpler method than filtration for sterilizing the lysato without damaging the phage.

Neisseria meningitidis is the main cause of bacterial meningitis and sepsis in the UK, and can potentially be lethal or cause long-term sequelae. Bexsero® (4CMenB) is a new multi-component vaccine approved by the European Commission for use in individuals aged ⩾2 months. A theoretical transmission model was constructed to assess the long-term effectiveness of Bexsero compared to standard care. The model was populated with UK-specific demographic data and calibrated to ensure that the transmission dynamics of meningococcal disease in the UK were adequately simulated. The model showed the best strategy to be a routine vaccination programme at ages 2, 3, 4, 12 months and 14 years combined with a 5-year catch-up programme in toddlers aged 12–24 months and adolescents aged 15–18 years. This would lead to a 94% reduction in meningococcal cases or 150 000 cases and 15 000 deaths over a 100-year time-frame.

1. The reaction of slowly growing pathogenic bacteria with specific fluorescent antibody provided a means for their rapid identification.

2. Fluorescein isothiocyanate was used to label the globulins of antisera as it had a number of advantages over fluorescein isocyanate.

3. Several other isothiocyanates and a few sulphonyl chlorides tested were inferior to flurescein isothiocyanate as labelling agents. Some of the compounds caused protein precipitation, and others gave a less intense or less distinctive fluorescence than did dluorescein isothiocyanate.

4. The tests were performed by taking impressions of bacterial micro-colonies on glass cover-slips, drying and fixing the preparations, staining them with labelled antiserum, washing in saline and mounting in glycerol saline. The preparations were than examined microscopically under ultra-violet light.

5. Micro-colonies of Br. suis, Past. tularensis and Past. pestis, when treated with homologous labelled antiserum, fluoresced brightly under ultra-violet light and the individual bacteria were sharply defined and stained at the periphery.

6. Micro-colonies of these and other bacteria stained with normal labelled serum, or heterologous labelled antiserum, showed either very dim fluorescence under ultra-violet light, with poor definition of in dividual bacteria, or no fluorescence at all.

7. The technique described permitted specific identification of Br. suis, Past. pestis and Past. tularensis within 20 hr. of inoculation of agar plates with material suspected of containing one of these organisms.

This investigation arose out of a line of work suggested by Dr G. S. Wilson. We should like to thank Dr D. W. Henderson and Major L. H. Kent for providing facilities for the work, Mr E. O. Powell for continual encouragement and supervision of the microscopy, Dr D. W. Henderson, Dr M. C. Lancaster and Dr D. A. L. Davies for supplying antisera, and Mr T. W. Pearce for valuable technical assistance and the photographs.

Every bacteriologist is only too well aware of the many problems presented by the preparation of culture media for the growth of bacteria in vitro.

Two cases of fatal melioidosis are described. The first a robust Indian labourer; the second a well-nourished, muscular European.

Case 1. Gradual onset. Irregular fever. Pain in the epigastrium. No physical signs of disease at first, except enlarged spleen; later, there were signs of consolidation at the bases of both lungs. Constipated at first; diarrhoea came on towards the end and the patient collapsed and died at the end of the third week.

At the autopsy; there were small patches of consolidation in the lungs, composed of minute suppurating tubercles. In the liver there were similar aggregations of small suppurating tubercles and two circumscribed abscesses. The gall-bladder was thickened. The spleen was enlarged and contained septic infarcts and abscesses. In the caecum there were small superficial ulcers. B. whitmori was cultivated from the lungs, spleen, liver and gall-bladder.

Animals were inoculated as follows: A guinea-pig, inoculated in the anterior nares with pus from the liver, died nine days later with caseous inflammation of the nasal passages and a caseous inguinal gland from which B. whitmori was recovered. A guinea-pig, inoculated subcutaneously with pus from the liver, died on the twenty-fifth day with abscesses in the lymphatic glands from which B. whitmori was cultivated. A guinea-pig, inoculated subcutaneously with a culture of the organism, died within sixteen hours from septicaemia. B. whitmori was recovered from the heart and spleen. A guinea-pig, inoculated subcutaneously with an attenuated culture, died on the twenty-fifth day with suppurating buboes and with abscesses in the liver and lungs from which B. whitmori was cultivated. Two horses were inoculated subcutaneously with cultures of the strain of B. whitmori cultivated from the patient. An abscess developed at the site of inoculation, in each case, but the local lesion healed and the animals have, so far, remained healthy.

Case 2. The illness commenced gradually with pain after food, occasional vomiting and looseness of the bowels. The temperature became high and of the swinging type, accompanied by rigors and sweats. The liver was enlarged. The patient died on the twenty-fifth day.

At the autopsy, two large abscesses were found in the liver, the gall-bladder was thickened and there were a few small superficial ulcers in the caecum. B. whitmori was cultivated from the liver abscess. No amoebae were found.

The following animals were inoculated. Two wild rats were inoculated subcutaneously with a culture from this case and both died from septicaemia in less than twenty-four hours. B. whitmori was recovered from the heart's blood. The result of the subcutaneous inoculation of a guinea-pig was the same. A guinea-pig, inoculated in the nostril, died on the fifth day with a cheesy deposit in the nose and septicaemia. Another guinea-pig, inoculated in the same way, but after the organism had been subcultivated repeatedly, died on the twelfth day, with caseous tracheal glands containing B. whitmori. A rabbit, inoculated subcutaneously, died in twenty-six hours from septicaemia with tubereles in the peritoneum. B. whitmori was cultivated from the peritoneum and from the heart's blood. A monkey fed on a culture remained healthy. A pony inoculated intravenously recovered after a week's fever.

The membrane-filter assay, GM1-ELISA, and DNA-DNA hybridization assay, were used to detect enterotoxigenic Escherichia coli (ETEC) in samples of water, weaning food, food preparation surface swabs, fingerprints of mothers, and the fingerprints and stools of children under 5 years of age, in 20 households in a Malaysian village. Weaning food and environmental samples were frequently contaminated by faecal coliforms, including ETEC. The membrane-filter assay detected and enumerated faecal coliforms and LT-ETEC in all types of water and weaning food samples. Highest concentrations of faecal coliforms and LT-ETEC were found in weaning food, followed by well-water, stored water and stored drinking water. The GM1-ELISA detected LT-ETEC in weaning food, food preparation surfaces, fingerprints and stool samples. The DNA-DNA hybridization assay detected a larger proportion of STa2-ETEC than the other toxotypes, either singly or in combination. All the assays in combination detected the presence of ETEC in all types of samples on at least one occasion in each household. It was not possible to classify households as consistently more or less contaminated with ETEC. On individual occasions it was possible to show a significant association of the presence of LT-ETEC between the fingerprints of children and their stools, fingerprints of mothers and children, and weaning food and the stools of the child consuming the food.

In May of 2018, PulseNet, the national molecular subtyping network for enteric pathogens, detected a multistate cluster of illnesses caused by an uncommon molecular subtype of Salmonella serovar Mbandaka. A case was defined as an illness in a person infected with the outbreak strain of Salmonella Mbandaka with illness onset on or after 3 March 2018 and before 1 September 2018. One-hundred thirty-six cases from 36 states were identified; 35 hospitalisations and no deaths were reported. Ill people ranged in age from <1 year to 95 years (median: 57 years). When standardised questionnaires did not generate a strong hypothesis, opened-ended interviews were performed. Sixty-three of 84 (75%) ultimately reported consuming or possibly consuming a specific sweetened puffed wheat cereal in the week before illness onset. Environmental sampling performed at the cereal manufacturing facility yielded the outbreak strain. The outbreak strain was also isolated from open cereal samples from ill people's homes and from a sealed retail sample. Due to these findings, the brand owner of the product issued a voluntary recall of the cereal on 14 June 2018. Additional investigation of the manufacturing facility identified persistent environmental contamination with Salmonella Mbandaka that was closely genetically related to other isolates in the outbreak. This investigation highlights the ability of Salmonella to survive in low-moisture environments, and the potential for prolonged outbreaks linked to products with long shelf lives and large distribution areas.

Longan County is considered a highly endemic area for hepatitis B virus (HBV). The plasma-derived vaccine has been used in newborns in this area since 1987. A cross-sectional survey was conducted to evaluate the long-term effectiveness of this vaccine. In total, 1634 participants born during 1987–1993 and who had received a series of plasma-derived HB vaccinations at ages 0, 1, and 6 months were enrolled. Serological HBV markers were detected and compared with previous survey data. Overall the prevalence of hepatitis B surface antigen (HBsAg) in all participants was 3·79%; 3·47% of subjects who had received the first dose within 24 h were HBsAg positive, and 8·41% of subjects who had received a delayed first dose were also HBsAg positive. There were 1527 subjects identified who had received the first dose within 24 h and whose HBsAg and anti-HBc prevalence increased yearly after immunization, while the anti-HBs-positive rate and vaccine effectiveness declined. The geometric mean concentration of antibody in the anti-HB-positive participants was 55·13 mIU/ml and this declined after immunization. Fewer than 2·0% of participants had anti-HB levels ⩾1000 mIU/ml. The data show that the protective efficacy of the plasma-derived vaccinations declined and administration of HB vaccine within 24 h of birth was very important. To reduce the risk of HBV infection in this highly endemic area, a booster dose might be necessary if anti-HBs levels fall below 10 mIU/ml after age 18 years. Furthermore, studies on the immune memory induced by plasma-derived HB vaccine are needed.