Hospital-based studies have determined high rates of community-associated methicillin-resistant Staphylococcus aureus (MRSA) in Indigenous populations. However, there is a paucity of community-based data. We obtained 20 years (1993–2012) of data on S. aureus isolates (N = 20 210) collected from community clinics that provide services for Indigenous communities in the Northern Territory, Australia. Methicillin resistance increased from 7% to 24%, resistance to macrolides remained stable at ~25%, and there was a slight increase in resistance to trimethoprim-sulfamethoxazole. The increase in methicillin resistance is concerning for the Indigenous communities represented by this data, but it is also of significance if virulent MRSA clones emerge and spread more widely from such settings.

Enterotoxin production by strains of Staphylococcus aureus isolated from routine samples of foods and from human beings was investigated. Twenty-one to 26% of 112 strains isolated from raw meat, sausages and poultry and 32–36% of 183 strains isolated from cooked foods, e.g. meat, chicken and frozen seafoods, produced enterotoxins A, B, C, D or E. Staph. aureus isolated from raw meat and chicken less frequently produced enterotoxins A, B, C or E and more frequently enterotoxin D, than those from cooked meat and seafoods. Of the 113 strains isolated from cheese and raw milk 6–11% produced enterotoxin and most of these produced enterotoxin D. Only a few strains isolated from foods produced enterotoxin E. Results of enterotoxin tests on Staph. aureus from human beings resembled those on strains from cooked foods.

On Friday, 22 November 1996, the microbiologist at a hospital in Lanarkshire, Scotland, identified presumptive Escherichia coli O157 in faecal specimens submitted by three patients with bloody diarrhoea, and confirmed its presence in one. Over the next 6 h, 12 more potential cases were identified. Investigations first indicated then confirmed a single food premises as the source of infection. Effective control measures were applied promptly. The outbreak was declared over on 20 January 1997, by which time 512 cases had been identified, and infection with the outbreak strain confirmed in 279. Twenty deaths occurred in cases during the outbreak and there were two more in cases during 1997. Seventeen of these deaths resulted from the outbreak. This paper describes the outbreak's epidemiological investigation, referring to other investigations, and control measures, where appropriate.

To monitor risk factors for illness, we conducted a case-control study of sporadic Shiga toxin-producing Escherichia coli O157 (STEC O157) infections in 1999–2000. Laboratory-confirmed cases of STEC O157 infection were identified through active laboratory surveillance in all or part of seven states. Patients and age-matched controls were interviewed by telephone using a standard questionnaire. Information was collected on demographics, clinical illness, and exposures to food, water, and animals in the 7 days before the patient's illness onset. During the 12-month study, 283 patients and 534 controls were enrolled. STEC O157 infection was associated with eating pink hamburgers, drinking untreated surface water, and contact with cattle. Eating produce was inversely associated with infection. Direct or indirect contact with cattle waste continues to be a leading identified source of sporadic STEC O157 infections.

The lethal dose of an ordinary pharmacological preparation is expressed in a simple statement of quantity. The lethal dose of a poisonous gas cannot as a rule be so expressed. The majority of such gases are rapidly destroyed in the body, and the building up of a lethal concentration in some critical portion of the organism is a race between the rate at which the gas is inhaled and the rate at which it is destroyed. Even in the cases of such gases as arsenuretted hydrogen which are destroyed only very slowly, and which are therefore cumulative poisons, the attainment of a lethal concentration in the body is a function not only of the concentration of the gas in the atmosphere, but of the time during which that atmosphere is breathed.

Virulent strains of Mycobacterium tuberculosis isolated from humans are divisible into five variants by using four tests: oxygen requirement (aerobic or microaerophilic), nitrate reductase activity, susceptibility to pyrazinamide (60 μg/ml) and susceptibility to thiophene-2-carboxylic acid hydrazide (5 μg/ml). The five variants are referred to as Classical human, Asian human, bovine, African I and African II. The relation of these variants to previously described types is discussed. This simple division has been shown to be useful in epidemiological studies.

The effects of cigarette smoking on the incidence of epidemic influenza and on the serological response to influenza vaccination with killed subunit and live attenuated vaccines have been investigated during comparative vaccine trials in Western Australia. It was found that cigarette smokers with no pre-epidemic haemagglutination-inhibiting (HI) antibody (titres of ≤ 12) were significantly more susceptible to epidemic influenza than non-smokers. Smokers were no more susceptible however, if they had possessed detectable pre-epidemic HI antibody. A significantly higher proportion of smokers sero-converted after receiving the live virus vaccine than their non-smoking counterparts, but this could not be correlated with pre-vaccination HI antibody titres. The longevity of the immune response to the subunit vaccine was severely depressed 50 weeks post-vaccination in smokers who had possessed little or no immunity before vaccination (titres of ≤ 12). This antibody deficit was not observed in live virus vaccinees or subunit vaccinees with pre-vaccination HI antibody (titres of ≥ 24). Post-vaccinal symptoms were similar regardless of vaccine group or smoking history.

A letter of inquiry was sent to 21 countries in Europe to ascertain their experience of diphtheria during the last 20 years. An analysis of the 15 replies showed that all relied on childhood vaccination and that this had reduced the annual incidence of the disease to a very low level. There was mention of three epidemics during the last ten years, and three countries identified several cases of skin diphtheria, mostly in patients who had contracted infection abroad.

Historically, the highest incidence rates of invasive Haemophilus influenzae disease in the world were found in North American and Australian Indigenous children. Although immunization against H. influenzae type b (Hib) led to a marked decrease in invasive Hib disease in countries where it was implemented, this disease has not been eliminated and its rates in Indigenous communities remain higher than in the general North American population. In this literature review, we examined the epidemiology of invasive H. influenzae disease in the pre-Hib vaccine era, effect of carriage on disease epidemiology, immune response to H. influenzae infection and Hib vaccination in Indigenous and Caucasian children, and the changing epidemiology after Hib conjugate vaccine has been in use for more than two decades in North America. We also explored reasons behind the continued high rates of invasive H. influenzae disease in Indigenous populations in North America. H. influenzae type a (Hia) has emerged as a significant cause of severe disease in North American Indigenous communities. More research is needed to define the genotypic diversity of Hia and the disease burden that it causes in order to determine if a Hia vaccine is required to protect the vulnerable populations.

The usefulness of sodium dodecyl sulphate–polyacrylamide gel electrophoresis patterns of cell envelope proteins for classifying strains of Acinetobacter calcoaceticus was studied using 129 isolates from 16 in-patients in a teaching hospital. In 11 patients, all of the isolates from each patient exhibited the same pattern irrespective of the body site or time of isolation. The patterns of the isolates from four other patients were indistinguishable, with the exception of one isolate per patient. In the isolates from one patient five patterns were observed. In several cases isolates from different patients exhibited the same pattern. The relative frequency of some of these patterns was low. Epidemiological data were compatible with the assumption that the concurrent presence of bacteria of these patterns in the patients was the result of cross-infection. For one pattern, which was seen in seven patients, cross-infection could not be substantiated. On the basis of analysis of electrophoretic patterns in combination with epidemiological data on a number of strains it is concluded that cell-envelope protein profiles appear to be a useful aid in studying the dissemination of Acinetobacter in the hospital environment.

A series of transmission studies was conducted to investigate the aetiology, or aetiologies, of emerging fatal epidemic disease syndromes affecting the common frog (Rana temporaria) in Britain. The syndromes, characterized by skin ulceration or systemic haemorrhages, were induced upon exposure to lesion homogenates or cultured ranavirus. The re-isolation of ranavirus from experimentally affected frogs fulfilled Koch's postulates. Aeromonas hydrophila, previously associated with similar lesions, was not significant to disease development. Unexpectedly, disease outcomes were influenced by both the source of agent and the route of exposure, indicating that different ranaviruses with different tissue tropisms and pathogeneses (possibly similar to quasi-species in RNA virus populations) are circulating in the British common frog population. Our findings confirm that ranavirus disease has emerged as an important cause of amphibian mortality in Britain.

Adenoviruses are found everywhere in the environment, and cause various health problems including symptoms of enteric illness, and respiratory illness. Despite their significance to public health, few studies have addressed the health risks associated with exposure to adenovirus. Human challenge studies have been published for a few adenoviruses, which involved exposure through oral ingestion, inhalation, intranasal and intraocular droplet inoculation. Nothwithstanding the different symptoms resulting from such exposures, infection can be defined as colonization of a corresponding mucosa. A two-level dose-response model was developed to describe the distributions of infectivity and pathogenicity in various challenge studies of adenovirus, incorporating differences in inoculation route as shift in average infectivity and pathogenicity. This dose-response model can be used to make predictions for the infectivity of adenovirus, specific to any of the four studied inoculation methods. The generalized adenovirus dose-response relationship for infection and acute illness takes into account variation in infectivity and/or pathogenicity across adenovirus types, as well as uncertainty due to limited data.

Dengue is a widespread vector-borne disease believed to affect between 100 and 390 million people every year. The interaction between vector, host and pathogen is influenced by various climatic factors and the relationship between dengue and climatic conditions has been poorly explored in India. This study explores the relationship between El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and dengue cases in India. Additionally, distributed lag non-linear model was used to assess the delayed effects of climatic factors on dengue cases. The weekly dengue cases reported by the Integrated Disease Surveillance Program (IDSP) over India during the period 2010–2017 were analysed. The study shows that dengue cases usually follow a seasonal pattern, with most cases reported in August and September. Both temperature and rainfall were positively associated with the number of dengue cases. The precipitation shows the higher transmission risk of dengue was observed between 8 and 15 weeks of lag. The highest relative risk (RR) of dengue was observed at 60 mm rainfall with a 12-week lag period when compared with 40 and 80 mm rainfall. The RR of dengue tends to increase with increasing mean temperature above 24 °C. The largest transmission risk of dengue was observed at 30 °C with a 0–3 weeks of lag. Similarly, the transmission risk increases more than twofold when the minimum temperature reaches 26 °C with a 2-week lag period. The dengue cases and El Niño were positively correlated with a 3–6 months lag period. The significant correlation observed between the IOD and dengue cases was shown for a 0–2 months lag period.

By the end of December 2000, the epidemiological system ‘Alert’ of the Public Health Institute in Tirane reported an outbreak of acute gastroenteritis. The outbreak involved children in Tirane and in the rural area. In total, 2722 children were seen in Tirane Hospital and 982 (56·4%) were treated for acute gastroenteritis. The age group with the highest morbidity was 0–5 years (89·7%), followed by the 6–9 (6·2%) and 10–15 years age groups (4·1%). The distribution of acute gastroenteritis cases, which occurred along the same water distribution system, suggests a waterborne origin. The nucleic acid amplification confirmed the co-circulation of different genotypes of rotavirus, mainly P[8]G9 and P[8]G3, responsible for the outbreak. Other enteric viruses such as astrovirus serotype 1, adenovirus and Norovirus, genogroups I and II were detected. Co-infections with different rotavirus genotypes and even with different enteric viruses were detected in several samples.

Cross-sectional surveys of infection in relation to ward structure and practice were made in 38 hospitals between 1967 and 1973, including repeat surveys in 12 hospitals. The survey team (a research nurse and a senior microbiologist or technician) visited one ward a day and entered data on patients, including appearance of wounds seen at change of dressings, on the structure of the ward, and on ward practices; bacteriological swabs were taken from noses of all patients and staff of wards visited and from infected or open wounds, also from some environmental sites. Effect of age, sex, length of hospital stay and antibiotic use on carriage of tetracycline-resistant Staphylococcus aureus and on post-operative sepsis are considered here.

Clinical infection (sepsis), further classified as ‘severe’, ‘moderate’ or ‘mild’ in accordance with a code of physical signs, including inflammation and suppuration, was found in 6·1% of clean undrained operation wounds. Drained wounds and those through hollow, heavily colonized viscera (‘contaminated’ wounds) had higher sepsis rates than undrained and ‘clean’ wounds; there was less sepsis with closed drainage and with small drains. Staph. aureus (24%) was the commonest single bacterial species, but gram-negative bacilli (50%) were found in a much larger proportion of septic wounds. The results showed that the infection rate was lowest among patients between 20 and 40 years old. Infection was significantly more common in male than in female patients.

Nasal carriage of tetracycline-resistant Staph. aureus, used as an index of hospital-acquired infection, was commonest in geriatric patients and least common in gynaecological patients. There was correlation between nasal carriage of tetracycline-resistant staphylococci and age of the patient, length of hospital stay, sex, (male greater than female), operative treatment, and treatment with tetracycline, ampicillin and nitrofurantoin, but not with penicillin.

1. The development and use of a medium which has selective properties for the growth of B. typhosus and B. proteus is described.

2. The principle of the method rests (1) on the positive property of the B. typhosus of being able to reduce a sulphite to a sulphide in the presence of glucose, (2) on the inhibitory action on the growth of B. coli of a bismuth sulphite in the presence of a certain excess of sodium sulphite.

3. The media finally developed are made in the following way:

A. To 100 c.c. of a melted 3 per cent. nutrient agar are added 5 c.c. of a 20 per cent. solution of glucose, 10 c.c. of a 20 per cent. solution of sodium sulphite (anhydrous), 5 c.c. of a standard bismuth solution. After boiling for two minutes an addition is made of 1 grm. of exsiccated sodium phosphate and 1 c.c. of an 8 per cent. solution of ferrous sulphate crystals.

Medium B is the same as above with the addition of 0·5 c.c. of a 1 per cent. watery solution of brilliant green. The standard liquor bismuthi is prepared by mixing 60 grm. bismuth citrate with 50 c.c. of distilled water and then with 20 c.c. liq. ammonii sp. gr. 0·880 and finally making the volume up to 500 c.c. with distilled water.

4. On these media the B. typhosus grows readily and forms flat blackdry surface colonies. B. proteus grows on the medium in a non-spreading fashion but does not form black colonies. B. coli either fails to grow or after a period of inhibition forms brown sticky raised colonies.

5. Bismuth media were used in the examination of 31 enteric stools and in 30 instances the infecting microorganism was successfully isolated. Single examinations only were made and the material was usually 24 to 48 hours old at the time of examination.

6. Emulsions of enteric stools which as shown by the usual media contained only a dozen or so of typhoid bacilli were found by our bismuth media actually to contain several thousand.

7. The isolation from a case of typhoid fever of a proteus X 19 strain is recored.

8. As regards its growth on bismuth sulphite media B. paratyphosus B behaves more like a reducing B. coli than a B. typhosus culture. For the isolation of B. paratyphosus B a lactose bile salt brilliant green medium is described.

We coupled the Wells–Riley equation and the susceptible–exposed–infected–recovery (SEIR) model to quantify the impact of the combination of indoor air-based control measures of enhanced ventilation and respiratory masking in containing pandemic influenza within an elementary school. We integrated indoor environmental factors of a real elementary school and aetiological characteristics of influenza to estimate the age-specific risk of infection (P) and basic reproduction number (R0). We combined the enhanced ventilation rates of 0·5, 1, 1·5, and 2/h and respiratory masking with 60%, 70%, 80%, and 95% efficacies, respectively, to predict the reducing level of R0. We also took into account the critical vaccination coverage rate among schoolchildren. Age-specific P and R0 were estimated respectively to be 0·29 and 16·90; 0·56 and 16·11; 0·59 and 12·88; 0·64 and 16·09; and 0·07 and 2·80 for five age groups 4–6, 7–8, 9–10, 11–12, and 25–45 years, indicating pre-schoolchildren have the highest transmission potential. We conclude that our integrated approach, employing the mechanism of transmission of indoor respiratory infection, population-dynamic transmission model, and the impact of infectious control programmes, is a powerful tool for risk profiling prediction of pandemic influenza among schoolchildren.

In September 1994, a complaint was registered at a public health unit concerning a cheese product. In addition, public health laboratories in Ontario reported an increase in the number of isolates of Salmonella berta from patients with diarrhoeal illness. A clinical, environmental and laboratory investigation was initiated to determine the nature of this outbreak. Isolates of Salmonella berta were compared using large fragment genomic fingerprinting by pulsed-field gel electrophoresis (PFGE). By late October, 82 clinical cases had been identified including 35 confirmed, 44 suspected and 3 secondary. The investigation linked illness to consumption of an unpasteurized soft cheese product produced on a farm and sold at farmers' markets. Subtyping results of patient, cheese and chicken isolates were indistinguishable, suggesting that the cheese was contaminated by chicken carcasses during production. The outbreak illustrates the potential role of uninspected home-based food producers and of cross-contamination in the transmission of foodborne bacterial pathogens.

The order Chiroptera is considered the second largest group of mammals in the world, hosting important zoonotic virus and bacteria. Bartonella and hemotropic mycoplasmas are bacteria that parasite different mammals’ species, including humans, causing different clinical manifestations. The present work aimed investigating the occurrence and assessing the phylogenetic positioning of Bartonella spp. and Mycoplasma spp. in neotropical bats sampled from Brazil. Between December 2015 and April 2016, 325 blood and/or tissues samples were collected from 162 bats comprising 19 different species sampled in five states of Brazil. Out of 322 bat samples collected, while 17 (5·28%) were positive to quantitative PCR for Bartonella spp. based on nuoG gene, 45 samples (13·97%) were positive to cPCR assays for hemoplasmas based on 16S rRNA gene. While seven sequences were obtained for Bartonella (nuoG) (n = 3), gltA (n = 2), rpoB (n = 1), ftsZ (n = 1), five 16S rRNA sequences were obtained for hemoplasmas. In the phylogenetic analysis, the Bartonella sequences clustered with Bartonella genotypes detected in bats sampled in Latin America countries. All five hemoplasmas sequences clustered together as a monophyletic group by Maximum Likelihood and Bayesian Inference analyses. The present work showed the first evidence of circulation of Bartonella spp. and hemoplasmas among bats in Brazil.

A compartmental, age-structured mathematical model was developed and recent US pertussis epidemiology data were used to evaluate the impact on pertussis infection rates of routine and targeted adult immunization strategies. Model simulations predict that the implementation of adolescent immunization only could reverse the current rise in pertussis infection rates but may lead to a resurgence of pertussis in subsequent decades. In contrast, inclusion of a routine adult strategy is likely to lead to sustained control of pertussis. Routine adult vaccination could control the disease even with relatively low coverage rates of 40% for routine vaccination of all adults every 10 years, or 65% for a targeted vaccination of close contacts of newborns completed by one booster dose for all adults. The model also predicts that the optimal age for this booster dose is 40 years. These results support the 2006 American Academy of Immunization Practices' recommendations for adolescent and adult vaccination against pertussis.