Molecular features of astrovirus associated with a gastroenteritis outbreak in an aged-care centre.

The study presented here was conducted in order to gain a better understanding of the role of astroviruses (AsVs) in outbreaks of gastroenteritis among the elderly. This report is the first to provide detailed information on the molecular characteristics of an AsV causing an outbreak in an aged-care centre and is the first to clearly establish that individuals infected in such an outbreak were, in fact, elderly. The outbreak under investigation took place in Victoria, Australia, in October 2005. Twelve individuals (mean age +/- standard deviation [SD] 85.5 +/- 12.3 years) became ill during the outbreak from a total population of 86 susceptible residents. The mean duration (+/-SD) of illness was 2.3 +/- 1.6 days; symptoms included diarrhoea, abdominal pain, nausea and headache. No bacterial pathogens were detected. AsV was identified in five faecal specimens using electron microscopy and reverse transcription-polymerase chain reaction methodologies; no other gastroenteritis virus was detected. Nucleotide sequence analysis indicated the AsV identified could be assigned to the 1d lineage of AsV serotype 1 and that the AsV was not a recombinant form. The findings, taken together with previous work, indicate the AsV serotype most commonly associated with gastroenteritis outbreaks among the elderly is serotype 1 AsV.

Increase in meningococcal disease associated with the emergence of a novel ST-11 variant of serogroup C Neisseria meningitidis in Victoria, Australia, 1999-2000.

In the years 1999-2000, there was an increase in the incidence of meningococcal disease in Victoria, largely caused by Neisseria meningitidis serogroup C. This change was associated with a shift in age distribution of cases, with relatively more disease appearing in the 15-29 year age group, and with 40/58 serogroup C isolates in 2000 exhibiting a new macrorestriction pattern (pattern A). Thirty-four of 52 pattern A isolates tested displayed the novel phenotype C:2a:P1.4, and were consistently porA VR type P1.7-2,4 by DNA sequencing. Nine of 10 representative pattern A isolates analysed displayed a housekeeping gene allele profile (ST-11) that is characteristic of the electrophoretic type (ET)-15 variant that has caused outbreaks in Canada, the Czech Republic and Greece. Meningococci belonging to the ST-11 complex that were isolated in Victoria prior to 1999 did not display either restriction pattern A or PorA VR type P1.7-2,4.

Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features.

AIMS: To establish the incidence and aetiology of haemolytic uraemic syndrome (HUS) in Australia and compare clinical and microbial characteristics of sporadic and outbreak cases. METHODS: National active surveillance through the Australian Paediatric Surveillance Unit with monthly case notification from paediatricians, July 1994 to June 1998. Children under 15 years presenting with microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal impairment were identified. RESULTS: Ninety eight cases were identified (incidence 0.64 per 10(5) children <15 years/annum and 1.35 per 10(5) children <5 years/annum). Eighty four were associated with diarrhoea (64 sporadic, 20 constituting an outbreak) and 14 were atypical. Shiga toxin producing Escherichia coli (STEC) O111:H- was the most common isolate in sporadic HUS and caused the outbreak. However O111:H- isolates from outbreak and sporadic cases differed in phage type and subtyping by DNA electrophoresis. STEC isolates from sporadic cases included O26:H-, O113:H21, O130:H11, OR:H9, O157:H-, ONT:H7, and ONT:H-. STEC O157:H7 was not isolated from any case. Only O111:H- isolates produced both Shiga toxins 1 and 2 and possessed genes encoding E coli attaching and effacing gene (intimin) and enterohemolysin. Outbreak cases had worse gastrointestinal and renal disease at presentation and more extrarenal complications. CONCLUSIONS: Linking national surveillance with a specialised laboratory service allowed estimation of HUS incidence and provided information on its aetiology. In contrast to North America, Japan, and the British Isles, STEC O157:H7 is rare in Australia; however, non-O157:H7 STEC cause severe disease including outbreaks. Disease severity in outbreak cases may relate to yet unidentified virulence factors of the O111:H- strain isolated.

Randomized, controlled trial comparing once daily and three times daily gentamicin in children with urinary tract infections.

OBJECTIVE: To undertake population pharmacokinetic modeling and to determine the safety and efficacy of once daily (OD) gentamicin dosing in children with severe urinary tract infections (UTI). METHODS: An open, randomized, controlled trial comparing OD with three times daily (TD) gentamicin dosing in hospitalized children ages 1 month to 12 years with UTI. Daily doses (milligrams per kg per day) of gentamicin in both groups were 7.5 (<5 years old), 6.0 (5 to 10 years old) and 4.5 (>10 years old). RESULTS: There were 179 children enrolled (90 OD, 89 TD). Baseline clinical characteristics and pathogens were similar, except that circulatory compromise and renal cortical scintigraphic defects were more common in the OD group. Median gentamicin treatment durations were 3.0 (OD) and 2.7 (TD) days. Mean peak gentamicin concentrations were 17.3 (OD) vs. 6.4 (TD) mg/l; 99% of peak concentrations were >7 mg/l in the OD group whereas 16% of peak concentrations were <5 mg/l in the TD group. Mean trough concentrations were 0.35 (OD) vs. 0.55 (TD) mg/l. In the OD group 4% of trough concentrations were > or = 2 mg/l, whereas in the TD group only 0.7% were > or = 2 mg/l. Age or prior elevated peak concentrations did not predict high trough concentrations. Population pharmacokinetic modeling of the data fitted a one-compartment model with first order elimination. There were no clinical or bacteriologic failures. The two disease-related complications were confined to the OD group. No nephro- or ototoxicity was identified. CONCLUSIONS: With age-appropriate dosing and measurement of serum trough concentrations before the second dose, OD gentamicin is safe and effective for the treatment of UTI requiring parenteral treatment in children aged 1 month to 12 years.

Multiple outbreaks of Norwalk-like virus gastro-enteritis associated with a Mediterranean-style restaurant.

The role of diverse infectious agents, particularly Norwalk-like viruses (NLV), in three successive gastro-enteritis outbreaks in one setting (a restaurant) was evaluated. Methods included standard bacteriological tests, specific tests for Escherichia coli, tests for verocytotoxins, electron microscopy (EM) for viruses and reverse transcription-PCR (RT-PCR) methodology for NLV. No pathogenic bacteria were detected. Verocytotoxin genes, although detected by PCR in the first outbreak, could not be confirmed in the E. coli isolated, so they did not appear to be of significance. NLV was the main agent detected in each of the three outbreaks. DNA sequencing and phylogenetic analysis of the amplified products obtained from the RT-PCR positive specimens indicated that only one NLV strain was involved in each outbreak, but the NLV strains responsible for the three outbreaks were different from each other. PCR technology for detection of NLV proved highly sensitive, but failed to detect one specimen which was positive by EM. The restaurant associated with the outbreaks is a Mediterranean-style restaurant where food from a common platter is typically eaten with fingers. The findings indicate that NLV was introduced by guests or staff and was not due to a long-term reservoir within the setting.

Invasive pneumococcal disease in the population of Victoria.

OBJECTIVES: To estimate morbidity and mortality rates for invasive Streptococcus pneumoniae (pneumococcal) disease in the non-Indigenous population of Victoria. DESIGN AND SETTING: Survey using data from a statewide voluntary laboratory surveillance scheme (1989-1998), statewide hospital discharge database (1995-1998), medical records of notified patients (1994-1995) and serotyping of notified isolates (1994-1998). MAIN OUTCOME MEASURES: Incidence of pneumococcal bacteraemia and pneumonia; predisposing factors; serotypes of isolates. RESULTS: Minimum estimates of annual incidence of invasive disease, based on laboratory surveillance data for 1995-1998, were 59 per 100,000 for children aged < 2 years, 25 per 100,000 for people aged > or = 65 years, and 8 per 100,000 overall. Annual incidence of pneumococcal pneumonia, calculated from hospital discharge data, was 99 per 100,000 for those aged > or = 65 years. Manifestations of invasive pneumococcal disease varied with age, with meningitis more common in infants, and pneumonia most common in older patients. A predisposing factor for pneumococcal infection was present in 48% of patients. Most isolates from infants (83%) belonged to serotypes in the proposed seven-valent infant vaccine, and 91% of isolates from people aged > or = 2 years belonged to serotypes in the current 23-valent adult vaccine. CONCLUSIONS: S. pneumoniae continues to be a major cause of morbidity and mortality in young children and the elderly in Victoria. More widespread use of the currently available pneumococcal vaccine in adults and introduction of an effective vaccine for infants should greatly reduce incidence of the disease.

Prevalence of enteric pathogens among community based asymptomatic individuals.

BACKGROUND AND AIMS: The objective of this study was to describe the prevalence of pathogenic microorganisms in asymptomatic individuals in a community study in Melbourne, Australia. METHODS: The study population was a subset of 2803 individuals participating in the Water Quality Study; a community based randomized trial. Faecal specimens (1091) were collected over a 3-month period from asymptomatic individuals. Specimens were tested for a range of bacteria including Salmonella, Shigella and Campylobacter species. Rotavirus and adenovirus were detected using a Rota-Adeno latex kit, and protozoa were detected using a permanent stain (modified iron-haemotoxylin). RESULTS: Twenty-eight known pathogens were identified from the 1091 faecal specimens, a total carriage rate of 2.6%. Giardia species were present in 18 specimens (1.6%), Salmonella in four (0.4%), Campylobacter in one (0.1%), Cryptosporidium in four (0.4%) and adenovirus in one (0.1%). Blastocystis hominis was found in 65 specimens. The median age of those without a pathogen was 12.5 years compared with 6.6 years for those with a pathogen (P=0.02). CONCLUSIONS: Except for Giardia, pathogens were rarely found in asymptomatic individuals in the community. The prevalence of pathogens was higher in children than adults.

Mycobacterium septicum sp. nov., a new rapidly growing species associated with catheter-related bacteraemia.

Rapidly growing mycobacteria are capable of causing several clinical diseases in both immunosuppressed and immunocompetent individuals. A previously unidentified, rapidly growing mycobacterium was determined to be the causative agent of central line sepsis in a child with underlying metastatic hepatoblastoma. Four isolates of this mycobacterium, three from blood and one from the central venous catheter tip, were studied. Phenotypic characterization, HPLC and genetic analysis revealed that while this organism most closely resembled members of the Mycobacterium fortuitum complex and Mycobacterium senegalense, it differed from all previously described species. Phenotypic tests useful in differentiating this species from similar rapidly growing mycobacteria included: growth at 42 degrees C, hydrolysis of acetamide, utilization of citrate, production of arylsulfatase (3-d), acidification of D-mannitol and i-myo-inositol, and susceptibility to erythromycin, vancomycin and tobramycin. The name Mycobacterium septicum is proposed for this new species. The type strain has been deposited in Deutsche Sammlung von Mikroorganismen und Zellkulturen as DSM 44393T and in the American Type Culture Collection as strain ATCC 700731T.

Enhanced measles surveillance during an interepidemic period in Victoria.

OBJECTIVE: To describe results of the first two years of enhanced measles surveillance in Victoria. DESIGN: Case series identified through enhanced measles surveillance. PARTICIPANTS AND SETTING: All measles cases notified to the Disease Control Section, Department of Human Services, Victoria, in 1997 and 1998. MAIN OUTCOME MEASURES: Proportion of notified cases laboratory confirmed as measles, rubella, or human parvovirus infection; identification of clusters (two or more linked cases of measles); and utility of the National Health and Medical Research Council clinical case definition for suspected measles. RESULTS: Rates of laboratory testing of notified cases improved after introduction of a paediatric phlebotomy service in July 1997, from 21 of 90 notified patients (23%) in the preceding six months, to 258 of 317 notified patients (81%) between July 1997 and December 1998. Of the 317, only 19 (6%) were laboratory confirmed with measles, while a further 26 (8%) were laboratory confirmed with human parvovirus infection (18) or rubella (8). Three clusters of measles, involving 11 cases, were identified during 1998. Use of the NHMRC case definition did not greatly improve the positive predictive value for diagnosis of measles above that of notification alone (14% versus 8%). CONCLUSIONS: Circulation of measles virus in Victoria in 1997 and 1998 appeared minimal. In this interepidemic period most notified cases of measles were not measles; to identify true cases, surveillance during an interepidemic period must include laboratory testing of notified cases.

A fatal case of angiostrongyliasis in an 11-month-old infant.

An 11-month-old boy developed flaccid quadriparesis after two months in Fiji, and was transferred to Australia, where a diagnosis of postinfectious myelitis was made. Despite peripheral blood eosinophilia, eosinophils were not detected in the cerebrospinal fluid, and an infective aetiology was not identified. The patient died of progressive bulbar dysfunction. At autopsy, numerous nematodes, identified as Angiostrongylus cantonensis, were seen in vessels of the lungs, brain and spinal cord, associated with pulmonary abscesses and eosinophilic meningitis. A notable feature was the presence of adult nematodes in the lung.

Bacteraemia in febrile children presenting to a pae3iatric emergency department.

OBJECTIVE: To determine the prevalence of bacteraemia in young febrile children presenting to a paediatric emergency department. DESIGN: Prospective observational case study. SETTING: Emergency Department of the Royal Children's Hospital, Melbourne, between May 1996 and May 1997. PARTICIPANTS: Patients aged 3-36 months presenting to the Emergency Department with temperature > or = 39 degrees C and without specific viral illnesses (varicella, croup or herpes gingivostomatitis). OUTCOME MEASURES: Bacteraemia (defined as presence of pathogenic bacteria in a blood culture), white blood cell count (WCC), McCarthy score, and final diagnosis based on clinical features and investigations. RESULTS: Bacteraemia was identified in 18 of 534 patients (3.4%). Pathogens isolated were Streptococcus pneumoniae (15), Neisseria meningitidis (2) and Klebsiella pneumoniae (1). Increased WCC counts (P < 0.001) and brief duration of fever (P < 0.001) were associated with bacteraemia. Nevertheless, clinical features, including McCarthy scores, and high WCC counts (> or = 20 x 10(9)/L) had < 10% predictive accuracy for bacteraemia. Overall, final diagnoses in the 534 febrile children included non-specific viral infections (25%), upper respiratory tract infections (24%), otitis media (10%), gastroenteritis (9%), pneumonia (7%), and urinary tract infection (5%). CONCLUSIONS: Most urban Australian children aged 3-36 months presenting to a paediatric emergency department with temperature > or = 39 degrees C without a clinical focus have a viral infection. However, 3%-4% have occult bacteraemia. Neither clinical features nor high WCC counts reliably identify these patients. As empiric antibiotics may contribute to increasing antibiotic resistance and have not been shown to prevent the rare complication of meningitis, we believe that close contact and regular review of these patients is preferable to empiric antibiotic therapy.

Central line sepsis in a child due to a previously unidentified mycobacterium.

A rapidly growing mycobacterium similar to strains in the present Mycobacterium fortuitum complex (M. fortuitum, M. peregrinum, and M. fortuitum third biovariant complex [sorbitol positive and sorbitol negative]) was isolated from a surgically placed central venous catheter tip and three cultures of blood from a 2-year-old child diagnosed with metastatic hepatoblastoma. The organism's unique phenotypic profile and ribotype patterns differed from those of the type and reference strains of the M. fortuitum complex and indicate that this organism may represent a new pathogenic taxon.

Combined infection of Norwalk-like virus and verotoxin-producing bacteria associated with a gastroenteritis outbreak.

Detection of multiple pathogens, particularly a combination of viruses and bacteria, is infrequently documented in outbreaks of gastroenteritis. This paper reports the presence of Norwalk-like virus (NLV) and enterohaemorrhagic verotoxin-producing Escherichia coli in one individual, and NLV and verotoxin-producing Aeromonas sobria in another individual, both part of a large gastroenteritis outbreak. The causes of gastroenteritis in such outbreaks may be more complex than previously thought.

Is it food poisoning?

Food borne infections and intoxications, typically manifesting as gastroenteritis, are a common community acquired illness in Australia. For infants, immunocompromised people, pregnant women and the elderly, food borne illness can be fatal. Food borne illness can be difficult to distinguish from illness transmitted by other routes, but specific pathogens, clinical syndromes, and epidemiological clues suggest possible 'food poisoning'. Management is usually supportive, but investigations provide information of public health value. Persons with gastroenteritis should be given simple advice to reduce the risk of transmitting infection to others, and educated about how enteric infections may be spread from infected persons and animals, and from food.

Pediatric bacteremia due to Staphylococcus warneri: microbiological, epidemiological, and clinical features.

Between 1991 and 1995, an apparent high rate of Staphylococcus warneri bacteremias at the Royal Children's Hospital, Melbourne, Victoria, Australia, raised the possibility of a virulent nosocomial strain. In a retrospective review of 30 S. warneri bacteremias in children, organisms were viable and verified in 22 episodes, 12 representing significant bacteremias. Of these 12 episodes, 2 pairs shared chromosomal DNA pulsed-field gel electrophoresis patterns in unconnected patients, dispelling concerns about a single virulent strain.

Antibiotic management of pneumococcal infections in an era of increased resistance.

Pneumococci are a leading cause of bacterial meningitis and bacteraemia, as well as pneumonia, otitis media and sinusitis in childhood. These organisms recently have shown a dramatic increase in antibiotic resistance. Penicillin-resistant pneumococci are of special concern as they are often resistant to other unrelated antibiotics. This is of particular significance to Aboriginal children who have among the highest rates of pneumococcal infection in the world. Laboratories should now test all invasive pneumococcal isolates for penicillin and third generation cephalosporin resistance. Local treatment guidelines are required for pneumococcal infections, especially for meningitis, taking into account the prevalence of resistant strains within the community. At present, penicillin and amoxycillin remain the drugs of choice for pneumococcal infections, with the exception of meningitis where initial empirical therapy must be with a third generation cephalosporin. Judicious antibiotic use, which avoids over-prescribing and unnecessary use of broad-spectrum agents, improved living standards in underprivileged communities and introduction of an effective conjugate vaccine, able to reduce the rates of pneumococcal infection and hopefully colonization, may limit the spread of resistant strains.

Streptococcal pharyngitis in a paediatric emergency department.

OBJECTIVE: To determine the prevalence and clinical features of beta-haemolytic streptococcal infection in children with acute pharyngitis and thereby to define those requiring antibiotic therapy. DESIGN: Prospective 2:1 case--control study. SETTING: Emergency Medicine Department of the Royal Children's Hospital, Melbourne, between May 1994 and May 1995. PARTICIPANTS: Cases (n = 271) were the first 10 self-referred children in each week with pharyngitis and no antibiotic use in the previous week. Controls (n = 135) were age-matched children without infection. MAIN OUTCOME MEASURES: Presence of groups A, C or G beta-haemolytic streptococci in oropharyngeal cultures; demographic and clinical characteristics. RESULTS: Group A beta-haemolytic streptococci (GABHS) were isolated from significantly more case than control children (cases, 57/271 [21%]; controls, 9/135 [7%]; odds ratio [OR], 3.7; P < 0.001). Groups C and G beta-haemolytic streptococci were isolated from 10 (4%) and 5 (2%) case children, respectively, but not from controls. Age > or = 4 years, tender cervical lymph nodes, pharyngotonsillitis, absent coryza and scarlatiniform rash were significantly associated with GABHS (P < 0.02). GABHS was uncommon in children aged < 4 years (4%), but was present in 12 of 14 children > or = 4 years with a rash (86%). However, most cases lacked a rash, and for children > or = 4 years likelihood of GABHS varied from 10%-65%, depending on other clinical features. CONCLUSIONS: In children aged < 4 years, GABHS is an unlikely cause of acute pharyngitis and symptomatic treatment alone should be considered. In children > or = 4 years, the likelihood of GABHS being the cause of acute pharyngitis increases with presence of scarlatiniform rash, pharyngotonsillitis and tender cervical nodes.

Human infection by Rhizopus azygosporus and the occurrence of azygospores in Zygomycetes.

Fungal isolates from the peritoneal cavity, kidney and liver, respectively, of three premature Australian babies are described as Rhizopus azygosporus. All three babies died. This is the first report as far as we know of the isolation of this fungus from human infections. It has previously been isolated only from Indonesian tempeh. The source of these infections was not determined. Rhizopus azygosporus is closely related to R. microsporus var. microsporus, var. rhizopodiformis and var. chinensis. The occurrence of azygospores in Zygomycetes and the taxonomic position of R. azygosporus are discussed.