Neonatal gastrointestinal mucormycosis mimicking necrotizing enterocolitis.
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Biomedical subjects
Publications and source records attributed to G L Gilbert.
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In this study, the phylogenetic relationships between the two biovars and 14 serovars of Ureaplasma urealyticum were studied using the sequences of four different genes or genetic regions, namely: 16S rRNA genes; 16S-23S rRNA gene spacer regions; urease gene subunits ureA, ureB, partial ureC and adjoining regions upstream of ureA, ureA-ureB spacer and ureB-ureC spacer; the 5'-ends of the multiple-banded antigen (MBA) genes. U. urealyticum genotypes, based on all four genomic sequences, could be clearly separated into two clusters corresponding with currently recognized biovars 1 and 2. Sequences were generally conserved within each biovar. However, there was heterogeneity within the 5'-end regions of the MBA genes of the four serovars of biovar 1; the sequence of serovar 3 was identical with the previously published sequence and differed by only three bases from that of serovar 14; but there were significant differences between the sequences of serovars 3 and 14 and those of serovars 1 and 6. Based on the phylogenetic analysis, support is given to previous recommendations that the two biovars of U. urealyticum be classified as distinct species, namely U. parvum and U. urealyticum for biovars 1 and 2, respectively. In the future, the relationship between the new species and clinical manifestations of ureaplasma infections should be studied.
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Legionella longbeachae is almost as frequent a cause of legionellosis in Australia as Legionella pneumophila, but epidemiological investigation of possible environmental sources and clinical cases has been limited by the lack of a discriminatory subtyping method. The purpose of this study was to examine the genetic variability among Australian isolates of L. longbeachae serogroup 1. Pulsed-field gel electrophoresis (PFGE) of SfiI fragments revealed three distinct pulsotypes among 57 clinical and 11 environmental isolates and the ATCC control strains of L. longbeachae serogroups 1 and 2. Each pulsotype differed by four bands, corresponding to <65% similarity. A clonal subgroup within each pulsotype was characterized by >88% similarity. The largest major cluster was pulsotype A, which included 43 clinical isolates and 9 environmental isolates and was divided into five subgroups. Pulsotypes B and C comprised smaller numbers of clinical and environmental isolates, which could each be further divided into three subgroups. The ATCC type strain of L. longbeachae serogroup 1 was classified as pulsotype B, subtype B3, while the ATCC type strain of L. longbeachae serogroup 2 was identified as a different pulsotype, LL2. SfiI macrorestriction analysis followed by PFGE showed that the Australian L. longbeachae strains are not a single clonal population as previously reported.
Ureaplasma urealyticum is a causative agent of nongonococcal urethritis and is implicated in the pathogenesis of several other diseases. The species is divided into 14 serovars and two biovars, of which biovar 1 is most commonly isolated from clinical specimens. Reported associations between individual serovars and diseases have been difficult to confirm because of practical difficulties with serotyping. The multiple-banded antigen (MBA) is the predominant U. urealyticum antigen recognized during infections in humans and probably has a significant role in virulence. The 5' end of the MBA gene is relatively conserved but contains biovar, and possibly serovar, specificity. The 5' ends of the MBA genes of standard strains of U. urealyticum biovar 1, consisting of serovars 1, 3, 6, and 14, were amplified, cloned into pUC19, and sequenced to identify serovar-specific differences. The 5' end of the MBA gene sequence of serovar 3 was identical with the previously published sequence and differed by only three bases from that of serovar 14. Significant differences between the MBA gene sequences allowed biovar 1 to be divided into two subgroups, containing serovars 3/14 and serovars 1 and 6, respectively, using primers UMS-125-UMA269 and UMS-125-UMA269'. Serovars 1 and 6 were distinguished by restriction enzyme analysis of the amplicon and/or by PCR specific for serovar 6. These methods were used to identify and type U. urealyticum in 185 (46.3%) of 400 genital specimens from women. Biovar 1 was detected in 89.2% and biovar 2 in 18.3% of positive specimens. Of 165 specimens containing U. urealyticum biovar 1, 22.2% contained more than one serovar and 46.7, 46.1, and 25.5% contained serovars 1, 3/14, and 6, respectively. U. urealyticum was found in a significantly higher proportion of pregnant women than in sex workers and other women attending a sexually transmissible diseases clinic (P < 0.01). The methods described are relatively rapid, practicable, and specific for serotyping isolates and for direct detection and identification of individual serovars in clinical specimens containing U. urealyticum biovar 1.
We used pulsed-field gel electrophoresis to study the epidemiology and population structure of Haemophilus influenzae type b. DNAs from 187 isolates recovered between 1985 and 1993 from Aboriginal children (n = 76), non-Aboriginal children (n = 106), and non-Aboriginal adults (n = 5) in urban and rural regions across Australia were digested with the SmaI restriction endonuclease. Patterns of 13 to 17 well-resolved fragments (size range, approximately 8 to 500 kb) defining 67 restriction fragment length polymorphism (RFLP) types were found. Two types predominated. One type (n = 37) accounted for 35 (46%) of the isolates from Aboriginals and 2 (2%) of the isolates from non-Aboriginals, and the other type (n = 41) accounted for 2 (3%) of the isolates from Aboriginals and 39 (35%) of the isolates from non-Aboriginals. Clustering revealed seven groups at a genetic distance of approximately 50% similarity in a tree-like dendrogram. They included two highly divergent groups representing 50 (66%) isolates from Aboriginals and 6 (5%) isolates from non-Aboriginals and another genetically distinct group representing 7 (9%) isolates from Aboriginals and 81 (73%) isolates from non-Aboriginals. The results showed a heterogeneous clonal population structure, with the isolates of two types accounting for 42% of the sample. There was no association between RFLP type and the diagnosis of meningitis or epiglottitis, age, sex, date of collection, or geographic location, but there was a strong association between the origin of isolates from Aboriginal children and RFLP type F2a and the origin of isolates from non-Aboriginal children and RFLP type A8b. The methodology discriminated well among the isolates (D = 0.91) and will be useful for the monitoring of postvaccine isolates of H. influenzae type b.
AIM: To examine the role of Ureaplasma urealyticum colonisation or infection in neonatal lung disease. METHODS: Endotracheal aspirates from ventilated infants less than 28 weeks of gestation were cultured for U urealyticum and outcomes compared in infants with positive and negative cultures. RESULTS: U urealyticum was isolated from aspirates of 39 of 143 (27%) infants. Respiratory distress syndrome (RDS) occurred significantly less often in colonised, than in non-colonised infants (p=0.002). Multivariate logistic regression analysis showed that in singleton infants, ureaplasma colonisation was the only independent (negative) predictor of RDS (OR 0.36; p=0. 02). Both gestational age (OR 0.46; p=0.006) and isolation of U urealyticum (OR 3.0; p=0.05) were independent predictors of chronic lung disease (CLD), as defined by requirement for supplemental oxygen at 36 weeks of gestational age. Multiple gestation was also a major independent predictor of RDS and CLD. CONCLUSIONS: Colonisation or infection with ureaplasma apparently protects premature infants against the development of RDS (suggesting intrauterine infection). However, in singleton infants, it predisposes to development of CLD, independently of gestational age. Treatment of affected infants after birth is unlikely to significantly improve the outcome and methods are required to identify and treat the women with intrauterine ureaplasmal infection, before preterm delivery occurs.
Three babies were referred with enteroviral meningitis and myocarditis during a 4-month period. During this same period there was an increased frequency of coxsackievirus B type 2 isolates reported to the National Centre for Disease Control. Myocarditis was simultaneous with meningitis in one baby, but delayed by 10 weeks in another, in whom myocarditis mimicked myocardial infarction. Two of the three mothers experienced abdominal pain, one with antepartum haemorrhage, which has been described previously with coxsackievirus infection in pregnancy. Diagnosis was made in two babies by polymerase chain reaction on cerebrospinal fluid.
The aim of this study was to evaluate the clinical use of a new culture system for the isolation of mycobacteria. Routine clinical specimens were cultured in the Mycobacteria Growth Indicator Tube, the radiometric Bactec 460 TB system and on Lowenstein Jensen (LJ) medium to compare recovery rates and times for detection of mycobacteria and contamination rates. MGIT was tested for its ability to support the growth of a wide range of mycobacterial species. Acid-fast bacilli (AFB) were detected on direct smears of 76 of 603 clinical specimens and mycobacteria were isolated by at least one method from 109 specimens; 93% of these were detected in the MGIT, 95% in the Bactec 460 TB system and 87% on LJ medium. The MGIT, Bactec and LJ media detected 92%, 97% and 95%, respectively, of 61 M. tuberculosis isolates and 94%, 94% and 77% of the 48 isolates belonging to the M. avium complex (MAC). The mean detection times in MGIT, Bactec and LJ media for M. tuberculosis were 22, 14 and 27 days respectively, and for MAC were 14, 12, and 29 days, respectively. Growth of M. tuberculosis was detected in Bactec, within 4 weeks, in 93% of the 61 culture-positive specimens, compared with only 61% in MGIT and 66% on LJ. The number of MAC detected within 4 weeks was similar in Bactec and MGIT, but less in LJ medium. Differences in sensitivity and time to detection of growth between media were greater for specimens in which AFB were not detected on direct smear than those on which AFB were seen. Contamination rates were similar in the three systems (3-4%). MGIT supported the growth of all 28 Mycobacterium spp. inoculated. MGIT has significant safety advantages and is less labour intensive than other methods, but the time to detection of M. tuberculosis, especially in smear-negative specimens, was longer in MGIT than in Bactec.
Histologic evidence of intestinal spirochetosis (IS) was found in 22 of 41 (53.7%) rectal biopsy specimens from homosexual men attending a sexually transmitted diseases clinic. Serpulina pilosicoli was cultured from 11 of the IS-positive biopsy specimens (50%) and from 2 specimens (10.5%) in which spirochetes were not observed. The association between seeing spirochetes in biopsy specimens and isolating S. pilosicoli was statistically significant, clearly indicating that this spirochete is the agent of IS.
The identification of Staphylococcus aureus directly from blood cultures is clinically relevant, but it requires a test that is both rapid and reliable. Previously, biochemical, immunological, tube coagulase, and thermostable-endonuclease methods have shown variable sensitivity and specificity. Testing directly from blood culture broth has not been described for the latex kit Staphaurex Plus (Murex Diagnostics Ltd.), and the modified conventional tests have not been used with the newer, continuously monitored blood culture systems. In addition, the commercial RAPIDEC staph kit (bioMerieux Vitek, Inc.) has been used to detect S. aureus directly from the Vital blood culture system (bioMerieux, Marcy l'Etoile, France), but its performance has not been evaluated with other continuously monitored systems. A total of 201 clinical blood cultures (BACTEC 9240 culture system; Johnston Laboratories, Inc.) in which a Gram stain showed gram-positive cocci resembling staphylococci were evaluated prospectively. The Staphaurex Plus kit, the tube coagulase test, the thermostable-endonuclease test, and the RAPIDEC staph kit were compared. The sensitivities were 23, 92, 85, and 98% and the specificities were 99, 100, 93, and 100%, respectively. The RAPIDEC staph kit was the most reliable test, with a diagnostic accuracy comparable to that of the best published results for any of the rapid tests. However, it was the most expensive of the tests and relatively labor-intensive. The tube coagulase test was also sensitive, the simplest to perform, and inexpensive.
OBJECTIVE: To assess the impact of rotavirus gastroenteritis on young children attending a paediatric hospital, their families and the health care system. DESIGN: Cross-sectional descriptive survey. SETTING: New Children's Hospital (Royal Alexandra Hospital for Children), Sydney, New South Wales, 15 July to 4 October 1996. PARTICIPANTS: Children aged under three years attending the Emergency Department with acute diarrhoea as the presenting symptom. OUTCOME MEASURES: Cases of rotavirus infection confirmed by enzyme-linked immunosorbent assay by age; rotavirus serotype; gastroenteritis severity score; estimated costs to parents (lost pay or leave, travel, medication and other expenses) and to the health care system (visits to Emergency Department and other health care workers, hospital admissions). RESULTS: 280 children were recruited (73% of 384 children who met the inclusion criteria and 27% of the 1037 aged under three years with acute gastroenteritis). Rotavirus was detected in 188 of the 280 (67%); most isolates were serotype G1 (86% of the 174 serotyped). Of the 188 children with confirmed rotavirus infection 78% were aged 7-24 months and 82% visited at least one other health care worker, usually a general practitioner. Seventy (37% of the 188) were admitted to hospital; 33 of these (47%) were aged 13-24 months. Estimated mean total cost per episode of rotavirus gastroenteritis was $1744 for children admitted to hospital and $441 for children not admitted. The mean cost to families was $493 for children admitted to hospital and $228 for children not admitted. CONCLUSIONS: Rotavirus gastroenteritis has a significant impact on young children, their families and the health care system. Prevention of severe disease through routine infant vaccination would be potentially cost-effective.
OBJECTIVE: To determine the usefulness of an indirect immunoflourescence antibody test for antibodies to Bartonella henselae in diagnosing cat scratch disease (CSD). DESIGN AND SETTING: Retrospective case survey of 354 patients whose sera were tested for antibodies to B. henselae at Royal Perth Hospital, Perth, and the Institute of Clinical Pathology and Medical Research, Sydney. In 1994; and measurement of the background prevalence of antibodies to B. henselae. MAIN OUTCOME MEASURES: Prevalence of antibodies to B. henselae, odds of a positive titre (> or = 64) in patients with and without specific risk factors for CSD and clinical features of the disease; prevalence of antibodies to B. henselae in randomly selected blood donors. RESULTS: Demographic, clinical and cat contact data were available for 303 patients. Sixty-four (21.1%) had a positive titre, as did 53 of 98 (54%) patients with a history of cat contact and lymphadenopathy. This proportion increased to 62% (38 of 61 patients) in patients with a history of cat scratch or bite and to 90.3% (28 of 31) in those with cat contact, lymphadenopathy and histological evidence of granulomatous lymphadenitis. Patients who developed lymphadenopathy after cat contact were significantly more likely to have a positive titre than those without this history (odds ratio [OR], 20.8; 95% confidence interval [95% Cl], 9.6-46; P < 0.0001). Inclusion of a history of a cat scratch or bite significantly raised the odds of being seropositive (OR, 13.7; 95% Cl, 6.8-28.1; P < 0.0001), and the presence of granulomas on lymph node biopsy further increased the odds (OR, 124.4; 95% Cl, 19.4-1073; P < 0.0001). The prevalence of antibodies to B. henselae in random blood donors in New South Wales was about 5% (five of 102 sera samples). CONCLUSIONS: The immunofluorescence antibody test for B. henselae can be expected to be positive in just over half the patients with clinically suspected CSD, and it has a positive predictive value of 83%. In a significant number of cases the diagnosis cannot be made on the basis of the results of immunofluorescence antibody testing alone and further investigations, including lymph node biopsy, may be required.
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.
The Binax legionella urinary antigen (LUA) enzyme immunoassay (Binax, Portland, Maine) was evaluated in 159 patients with suspected or proven legionellosis and 209 controls. A positive LUA test was found in 37% of patients with suspected legionellosis overall and in 83% of those with proven Legionella pneumophila serogroup 1 infection. The sensitivity of the LUA test was significantly greater than that of the direct fluorescent-antigen test (83 versus 42%; P < 0.0001) but not significantly different from that of culture (85%) or serology (91%); specificity was at least 99.5%.
A slowly growing anaerobic Helicobacter species was isolated from the blood cultures of two human immunodeficiency virus-positive patients admitted to Westmead Hospital, Westmead, Australia, with fevers. The morphology of the isolates was consistent with Helicobacter cinaedi or Helicobacter fennelliae. The results of culture growth conditions, biochemical tests, gas chromatography data, ribotyping, and 16S rDNA sequencing showed that these isolates represent a new Helicobacter species, for which the name Helicobacter westmeadii has been proposed.
The incidence of tuberculosis, in decline in Western countries for years, is increasing again. Inadequate therapy leads to the emergence of multidrug-resistant tuberculosis, which is difficult to treat and for which there is no effective chemoprophylaxis. Prevention is the most important strategy.