John S. Spika

Growing concerns and recent outbreaks involving non-O157:H7 serotypes of verotoxigenic Escherichia coli

Verocytotoxin-producing E. coli (VTEC) of serotype O157:H7 have been shown to be important agents of foodborne disease in humans worldwide. While the majority of research effort has been targeted on this serotype it is becoming more evident that other serotypes of VTEC can also be associated with human disease. An increasing number of these non-O157:H7 VTEC have been isolated from humans suffering from HUS and diarrhea. Recently a number of foodborne outbreaks in the USA, Australia, and other countries have been attributed to non-O157:H7 VTEC serotypes. Surveys of animal populations in a variety of countries have shown that the cattle reservoir contains more than 100 serotypes of VTEC, many of which are similar to those isolated from humans. The diversity and complexity of the VTEC family requires that laboratories and public health surveillance systems have the ability to detect and monitor all serotypes of VTEC.

Chloramphenicol-resistant Salmonella newport traced through hamburger to dairy farms. A major persisting source of human salmonellosis in California

Animal-to-human transmission of drug-resistant salmonella and the role of antimicrobial use in food animals in the emergence of these bacteria are controversial subjects. Investigation of a 4.9-fold increase in Salmonella newport isolations from Californians in 1985 showed that 87 percent of the isolates had an unusual antimicrobial-resistance pattern (including chloramphenicol resistance) and a single, identical plasmid. Interviews of 45 patients and 89 matched controls in Los Angeles County showed that illness was associated with penicillin or tetracycline use during the month before onset (P less than 0.001) and with eating ground beef during the week before onset (P = 0.052). The epidemic strain was isolated from hamburger products eaten by cases, abattoirs where the animals from which the meat came were slaughtered, dairies that sent cows for slaughter on days when culture-positive products were processed, and ill dairy cows. Isolation of salmonella from beef carcasses in abattoirs correlated with the proportion of dead or moribund animals received for slaughter (r = 0.60, P less than 0.05). Isolation of chloramphenicol-resistant salmonella from dairy farms was associated with the use of chloramphenicol at those dairies. We conclude that food animals are a major source of antimicrobial-resistant salmonella infections in humans and that these infections are associated with antimicrobial use on farms.

Hemolytic uremic syndrome and diarrhea associated with Escherichia coli 0157:H7 in a day care center

Three cases of hemolytic uremic syndrome with bloody diarrhea occurred during an outbreak of diarrheal illness in children aged 4 months to 9 years who attended a day care center. Thirty-six (34%) of 107 had diarrhea (three or more loose or watery stools in 24 hours) lasting ≧3 days. Thirty-one (48%) of 64 children younger than 4 years of age but only (12%) of 43 in the older classes became ill (relative risk 4.0, P Escherichia coli 0157:H7 was detected in two of eight stool specimens from children who had bloody diarrhea (one with hemolytic uremic syndrome), two of seven with nonbloddy diarrhea, and none of nine who remained well. All three stool specimens obtained at ≦6 days compared with one of nine obtained at ≧6 days after onset yielded this organism (P E. coli 0157:H7 can cause hemolytic uremic syndrome and both nonbloody and bloody diarrhea, and can spread within families and through modes other than foodborne transmission.

Risk of severe outcomes among patients admitted to hospital with pandemic (H1N1) influenza

Background: We describe the disease characteristics and outcomes, including risk factors for admission to intensive care unit (ICU) and death, of all patients in Canada admitted to hospital with pandemic (H1N1) influenza during the first five months of the pandemic. Methods: We obtained data for all patients admitted to hospital with laboratory-confirmed pandemic (H1N1) influenza reported to the Public Health Agency of Canada from Apr. 26 to Sept. 26, 2009. We compared inpatients who had nonsevere disease with those who had severe disease, as indicated by admission to ICU or death. Results: A total of 1479 patients were admitted to hospital with confirmed pandemic (H1N1) influenza during the study period. Of these, 1171 (79.2%) did not have a severe outcome, 236 (16.0%) were admitted to ICU and survived, and 72 (4.9%) died. The median age was 23 years for all of the patients, 18 years for those with a nonsevere outcome, 34 years for those admitted to ICU who survived and 51 years for those who died. The risk of a severe outcome was elevated among those who had an underlying medical condition and those 20 years of age and older. A delay of one day in the median time between the onset of symptoms and admission to hospital increased the risk of death by 5.5%. The risk of a severe outcome remained relatively constant over the five-month period. Interpretation: The population-based incidence of admission to hospital with laboratory-confirmed pandemic (H1N1) influenza was low in the first five months of the pandemic in Canada. The risk of a severe outcome was associated with the presence of one or more underlying medical conditions, age of 20 years or more and a delay in hospital admission.

Invasive Streptococcus pneumoniae Infection in Latin American Children: Results of the Pan American Health Organization Surveillance Study

Protein-polysaccharide conjugate vaccines against Streptococcus pneumoniae promise to be an effective public health intervention for children, especially in an era of increasing antimicrobial resistance. To characterize the distribution of capsular types in Latin America, surveillance for invasive pneumococcal infection in children < or = 5 years of age was done in six countries between February 1993 and April 1996. Fifty percent of 1,649 sterile-site isolates were from children with pneumonia, and 52% were isolated from blood. The 15 most common of the capsular types prevalent throughout the region accounted for 87.7% of all isolates. Overall, 24.9% of isolates had diminished susceptibility to penicillin: 16.7% had intermediate resistance and 8.3% had high-level resistance. Three customized vaccine formulas containing 7, 12, and 15 capsular types were found to have regional coverages of 72%, 85%, and 88%, respectively. This study emphasizes the need for local surveillance for invasive pneumococcal disease prior to the development and evaluation of protein-polysaccharide conjugate vaccines for children.

Incidence of hospital admissions and severe outcomes during the first and second waves of pandemic (H1N1) 2009

Background Canada experienced two distinct waves of pandemic (H1N1) influenza during the 2009 pandemic, one in the spring and the second in early fall 2009. We compared the incidence of hospital admissions and severe outcomes (admission to intensive care unit [ICU] and death) during the two waves. Methods We reviewed data on all laboratory-confirmed cases of pandemic (H1N1) influenza that resulted in hospital admission, ICU admission or death reported to the Public Health Agency of Canada by all provinces and territories from Apr. 18, 2009, to Apr. 3, 2010. Results A total of 8678 hospital admissions (including 1473 ICU admissions) and 428 deaths related to pandemic (H1N1) influenza were reported during the pandemic and post-peak period. There were 4.8 times more hospital admissions, 4.0 times more ICU admissions and 4.6 times more deaths in the second pandemic wave than in the first wave. ICU admissions and deaths as a proportion of hospital admissions declined in the second wave; there was a 16% proportional decline in ICU admissions and a 6% proportional decline in deaths compared with the first wave. Compared with patients admitted to hospital in the first wave, those admitted in the second wave were older (median age 30 v. 23 years) and more had underlying conditions (59.7% v. 47.5%). Pregnant women and Aboriginal people accounted for proportionally fewer patients who were admitted to hospital or who died in the second wave than in the first. Interpretation The epidemiologic features of the first and second waves of the 2009 pandemic differed. The second wave was substantially larger and, although the patients admitted to hospital were older and more of them had underlying conditions, a smaller proportion had a severe outcome.

Acute lower respiratory infections: a major cause of death in children in Bangladesh

The importance of acute lower respiratory infections (ALRI) as a cause of death in children was estimated using systematically collected demographic data on the population of the Teknaf area of southern Bangladesh. Of 1349 children aged 1-59 months who died between 1 January 1982 and 31 December 1985, ALRI was diagnosed by verbal autopsy in 390 (29%) and was the leading cause of death. ALRI mortality rates were highest in the youngest age groups (136/1000 for those less than or equal to 5 months) and decreased in older children (16/1000 for those 3-4 years old). Half of all fatal ALRI cases occurred in children less than 6 months old. In older children, ALRI-associated deaths tended to occur during the months October to January, while deaths in infants tended to follow the seasonal birth pattern. Significant predisposing factors for fatal ALRI were malnutrition and measles, detected, respectively, in 18% and 8% of children who died from ALRI. This study emphasizes the importance of ALRI as a major cause of death in developing countries and suggests that interventions to reduce childhood mortality are needed and should be targeted to specific age groups at risk.

Supplementary Immunization Activities to Achieve Measles Elimination: Experience of the European Region

BACKGROUND Supplementary immunization activities (SIAs) using measles-containing vaccine (MCV) have had a substantial impact on reducing mortality associated with measles worldwide. METHODS To assess impact of SIAs on measles incidence in the World Health Organization European Region and their role at the final stages of measles elimination efforts in Europe, we reviewed information on SIAs, measles surveillance, and routine vaccination coverage during 2000-2009. RESULTS During 2000-2009, >57 million persons received MCV through SIAs in 16 countries. The Region primarily focused on catch-up campaigns with wider target age groups than in other regions and subsequently relied on routine vaccination rather than periodic follow-up SIAs for the second MCV dose. In addition, the concept of SIAs has been expanded from short-term (<30 days) mass campaigns implemented in other regions to incorporate vaccination efforts over longer periods and outbreak response vaccination. In 2009, 14 of 16 countries that conducted SIAs reported no measles cases or <1 case per 1,000,000 population, reflecting the post-SIA decrease in incidence. CONCLUSIONS SIAs have made a substantial contribution to the success of measles elimination efforts and will likely remain an important strategy for interrupting measles virus transmission in the European Region, although specific approaches will vary by country.

Canadian perspectives on verocytotoxin-producing Escherichia coli infection

Infection with verocytotoxin-producing Escherichia coli (VTEC) became nationally reportable in 1990. Between 1990 and 1994, the national incidence of reported infections ranged from 3 to 5.3 per 100,000 inhabitants. Most cases are sporadic and are caused by E. coli O157:H7. Recent investigations have identified that, in addition to exposure to undercooked ground beef, contact with cattle, consumption of well water, and exposure to rural environments are important risk factors for VTEC infection. Also, results of case control studies and detection of asymptomatic fecal carriage of E. coli O157:H7 and other VTEC in farm family members and abattoir workers have led to an increasing emphasis on person-to-person spread in the epidemiology of VTEC infection. Controlling E. coli O157:H7 and other VTEC at the farm level may therefore have a broader impact than simply reducing the risk of foodborne VTEC infection. Longitudinal studies on dairy farms have demonstrated that E. coli O157:H7 carriage by cattle at the farm and animal level is often transient, and that cattle, rather than the farm environment, are the major reservoir for this organism on dairy farms. Small herds that are controlled by traditional management practices have the highest risk for VTEC infection. Further studies are likely to result in development of effective strategies to control VTEC at the farm level.

Laboratory characterization of invasive Haemophilus influenzae isolates from Nunavut, Canada, 2000-2012.

Background With invasive Haemophilus influenzae serotype b (Hib) disease controlled by vaccination with conjugate Hib vaccines, there is concern that invasive disease due to non-serotype b strains may emerge. Objective This study characterized invasive H. influenzae (Hi) isolates from Nunavut, Canada, in the post-Hib vaccine era. Methods Invasive H. influenzae isolates were identified by conventional methods at local hospitals; and further characterized at the provincial and federal public health laboratories, including detection of serotype antigens and genes, multi-locus sequence typing and antibiotic susceptibility. Results Of the 89 invasive H. influenzae cases identified from 2000 to 2012, 71 case isolates were available for study. There were 43 serotype a (Hia), 12 Hib, 2 Hic, 1 Hid, 1 Hie, 2 Hif and 10 were non-typeable (NT). All 43 Hia were biotype II, sequence type (ST)-23. Three related STs were found among the Hib isolates: ST-95 (n=9), ST-635 (n=2) and ST-44 (n=1). Both Hif belonged to ST-124 and the 2 Hic were typed as ST-9. The remaining Hid (ST-1288) and Hie (ST-18) belonged to 2 separate clones. Of the 10 NT strains, 3 were typed as ST-23 and the remaining 7 isolates each belonged to a unique ST. Eight Hib and 1 NT-Hi were found to be resistant to ampicillin due to β-lactamase production. No resistance to other antibiotics was detected. Conclusion During the period of 2000–2012, Hia was the predominant serotype causing invasive disease in Nunavut. This presents a public health concern due to an emerging clone of Hia as a cause of invasive H. influenzae disease and the lack of published guidelines for the prophylaxis of contacts. The clonal nature of Hia could be the result of spread within an isolated population, and/or unique characteristics of this strain to cause invasive disease. Further study of Hia in other populations may provide important information on this emerging pathogen. No antibiotic resistance was detected among Hia isolates; a small proportion of Hib and NT-Hi isolates demonstrated resistance to ampicillin due to β-lactamase production.Background With invasive Haemophilus influenzae serotype b (Hib) disease controlled by vaccination with conjugate Hib vaccines, there is concern that invasive disease due to non-serotype b strains may emerge. Objective This study characterized invasive H. influenzae (Hi) isolates from Nunavut, Canada, in the post-Hib vaccine era. Methods Invasive H. influenzae isolates were identified by conventional methods at local hospitals; and further characterized at the provincial and federal public health laboratories, including detection of serotype antigens and genes, multi-locus sequence typing and antibiotic susceptibility. Results Of the 89 invasive H. influenzae cases identified from 2000 to 2012, 71 case isolates were available for study. There were 43 serotype a (Hia), 12 Hib, 2 Hic, 1 Hid, 1 Hie, 2 Hif and 10 were non-typeable (NT). All 43 Hia were biotype II, sequence type (ST)-23. Three related STs were found among the Hib isolates: ST-95 (n=9), ST-635 (n=2) and ST-44 (n=1). Both Hif belonged to ST-124 and the 2 Hic were typed as ST-9. The remaining Hid (ST-1288) and Hie (ST-18) belonged to 2 separate clones. Of the 10 NT strains, 3 were typed as ST-23 and the remaining 7 isolates each belonged to a unique ST. Eight Hib and 1 NT-Hi were found to be resistant to ampicillin due to β-lactamase production. No resistance to other antibiotics was detected. Conclusion During the period of 2000–2012, Hia was the predominant serotype causing invasive disease in Nunavut. This presents a public health concern due to an emerging clone of Hia as a cause of invasive H. influenzae disease and the lack of published guidelines for the prophylaxis of contacts. The clonal nature of Hia could be the result of spread within an isolated population, and/or unique characteristics of this strain to cause invasive disease. Further study of Hia in other populations may provide important information on this emerging pathogen. No antibiotic resistance was detected among Hia isolates; a small proportion of Hib and NT-Hi isolates demonstrated resistance to ampicillin due to β-lactamase production.Background With invasive Haemophilus influenzae serotype b (Hib) disease controlled by vaccination with conjugate Hib vaccines, there is concern that invasive disease due to non-serotype b strains may emerge. Objective This study characterized invasive H. influenzae (Hi) isolates from Nunavut, Canada, in the post-Hib vaccine era. Methods Invasive H. influenzae isolates were identified by conventional methods at local hospitals; and further characterized at the provincial and federal public health laboratories, including detection of serotype antigens and genes, multi-locus sequence typing and antibiotic susceptibility. Results Of the 89 invasive H. influenzae cases identified from 2000 to 2012, 71 case isolates were available for study. There were 43 serotype a (Hia), 12 Hib, 2 Hic, 1 Hid, 1 Hie, 2 Hif and 10 were non-typeable (NT). All 43 Hia were biotype II, sequence type (ST)-23. Three related STs were found among the Hib isolates: ST-95 (n=9), ST-635 (n=2) and ST-44 (n=1). Both Hif belonged to ST-124 and the 2 Hic were typed as ST-9. The remaining Hid (ST-1288) and Hie (ST-18) belonged to 2 separate clones. Of the 10 NT strains, 3 were typed as ST-23 and the remaining 7 isolates each belonged to a unique ST. Eight Hib and 1 NT-Hi were found to be resistant to ampicillin due to β-lactamase production. No resistance to other antibiotics was detected. Conclusion During the period of 2000-2012, Hia was the predominant serotype causing invasive disease in Nunavut. This presents a public health concern due to an emerging clone of Hia as a cause of invasive H. influenzae disease and the lack of published guidelines for the prophylaxis of contacts. The clonal nature of Hia could be the result of spread within an isolated population, and/or unique characteristics of this strain to cause invasive disease. Further study of Hia in other populations may provide important information on this emerging pathogen. No antibiotic resistance was detected among Hia isolates; a small proportion of Hib and NT-Hi isolates demonstrated resistance to ampicillin due to β-lactamase production.