Investigation of tuberculosis transmission in Canadian Arctic Inuit communities using DNA fingerprinting.

OBJECTIVE: To understand the transmission of tuberculosis in Inuit communities in the Baffin region of the Canadian Arctic. METHODS: Twenty-one isolates of Mycobacterium tuberculosis from 19 Inuit patients diagnosed with tuberculosis between February 1991 and September 1993 were analyzed by DNA fingerprinting. The DNA fingerprints were achieved by the standard restriction fragment length polymorphism (RFLP) technique, with subsequent probing using the repetitive insertion segment IS6110. RESULTS: The isolates could be divided into three DNA types. The DNA types generally corresponded to the geographic origins of the patients. In most instances only one DNA type of M. tuberculosis was identified in each community. This suggests that a single case was the start of each of the three clusters, most likely due to reactivation. CONCLUSIONS: The results show that molecular typing of M. tuberculosis was useful in determining the mode of transmission of tuberculosis in a remote area of the Canadian Arctic where the disease is endemic. In addition, the information provides useful information for planning interventions in this setting.

Use of gas chromatographic fatty acid and mycolic acid cleavage product determination to differentiate among Mycobacterium genavense, Mycobacterium fortuitum, Mycobacterium simiae, and Mycobacterium tuberculosis.

Three Mycobacterium genavense strains and three American Type Culture Collection reference strains each of Mycobacterium fortuitum, Mycobacterium simiae, and Mycobacterium tuberculosis were subcultured onto Mycobacteria 7H11 agar (Difco Laboratories, Detroit, Mich.) supplemented with mycobactin J (Allied Laboratories, Fayette, Mo.). After 4 weeks of incubation at 37 degrees C in 10% CO2, the cultures were analyzed by gas-liquid chromatography (GLC) for their fatty acids and mycolic acid cleavage products. M. fortuitum was clearly differentiated from M. genavense by the presence of the specific marker 2-methyloctadecenoic acid in M. fortuitum and by the ratio of tetracosanoic acid to hexacosanoic acid. This ratio was <1 for M. genavense and >3 for M. fortuitum. M. fortuitum also contained docosanoic acid, which was not detected in M. genavense. M. genavense, M. simiae, and M. tuberculosis, which have similar GLC profiles, were also differentiated from each other by the presence of either cis-10-hexadecenoic acid or cis-11-hexadecenoic acid and by tetradecanoic acid content.

Detection and confirmation of Mycoplasma pneumoniae in urogenital specimens by PCR.

Following the isolation of Mycoplasma pneumoniae from urogenital specimens (M. Goulet, R. Dular, J. G. Tully, G. Billows, and S. Kasatiya, J. Clin. Microbiol. 33:2823-2825, 1995), a study was undertaken to confirm the observations by PCR. Specific primers directed to the P1 adhesin gene of M. pneumoniae were used. A total of 300 genital specimens were tested for M. pneumoniae and Mycoplasma genitalium by culture and PCR. Of these, 15 were positive by culture and 17 were positive by PCR for M. pneumoniae. No M. genitalium was detected in any of the specimens by either method. The present study demonstrates that PCR is sensitive and rapid compared to cumbersome culture methods and can be used to detect M. pneumoniae in urogenital specimens in a routine diagnostic laboratory.

Taxonomic changes in tailed phages of enterobacteria.

Out of 136 new phages, 80 (59%) are classified into 23 species according to morphology and physicochemical properties. Six new species are described and species beta 4, from a previous classification scheme, is renamed T1. The morphology of 36 phage species is schematically represented.

Taxonomic changes in tailed phages of enterobacteria.

Out of 136 new phages, 80 (59%) are classified into 23 species according to morphology and physicochemical properties. Six new species are described and species b4, from a previous classification scheme, is renamed T1. The morphology of 36 phage species is schematically represented.

Direct identification of Mycobacterium species in Bactec 7H12B medium by gas-liquid chromatography.

Twenty-nine Mycobacterium reference strains representing 10 species and 60 mycobacterial cultures isolated from sputum specimens were studied. These cultures were grown in Bactec 7H12B medium (Becton Dickinson and Co., Paramus, N.J.) supplemented with oleic acid-albumin-dextrose-catalase enrichment broth (Becton Dickinson and Co., Cockeysville, Md.). The cultures were analyzed by gas-liquid chromatography for their fatty acids, secondary alcohols, and mycolic acid cleavage products. All of the clinical isolates could be identified by comparing their gas-liquid chromatography profiles with those of the reference strains. The data indicate that this method significantly shortens the turnaround time and could be used for the early detection and identification of mycobacterial species.

Isolation of Mycoplasma pneumoniae from the human urogenital tract.

Mycoplasma pneumoniae is a common etiologic agent of lower respiratory tract infections in humans. However, it has been reported previously that the organism has occasionally been isolated from sites other than the oropharynx and respiratory tract. We report the isolation of 24 strains of M. pneumoniae from urogenital specimens obtained from 22 female patients. Most isolates were of cervical origin from patients attending several local gynecological clinics over a 2-year period. Strains were also isolated from the urethra of one of three healthy male sexual partners of female patients positive for the organism. Single serum specimens obtained from three female patients and three different male sexual partners showed antibody levels suggestive of either recent respiratory infection or genital tract colonization with M. pneumoniae. Although there is no apparent definitive explanation for the localized outbreak of the organism at these unusual sites, the possible transfer through sexual and/or orogenital contact remains the most likely mode of transmission. The occurrence of an organism with obvious pathogenicity for human epithelial tissue in the urogenital tract suggests such transfer could play a role in genital tract infection.

Bacillus cereus and Bacillus thuringiensis isolated in a gastroenteritis outbreak investigation.

During investigation of a gastroenteritis outbreak in a chronic care institution, Norwalk virus was found in stool specimens from two individuals and bacterial isolates presumptively identified as Bacillus cereus were isolated from four individuals (including one with Norwalk virus) and spice. Phage typing confirmed all Bacillus clinical isolates were phage type 2. All clinical isolates were subsequently identified as B. thuringiensis when tested as a result of a related study (L. Leroux, personal communication). Eight of 10 spice isolates were phage type 4. All B. cereus and B. thuringiensis isolates showed cytotoxic effects characteristic of enterotoxin-producing B. cereus. An additional 20 isolates each of B. cereus and B. thuringiensis from other sources were tested for cytotoxicity. With the exception of one B. cereus, all showed characteristic cytotoxic patterns.

Bacillus cereus phage typing as an epidemiological tool in outbreaks of food poisoning.

Bacillus cereus is responsible for an increasing number of food poisoning cases. By using 12 bacteriophages isolated from sewage, a typing scheme for B. cereus isolates from outbreaks or sporadic cases of food poisoning was developed. The phages belonged to three morphotypes. Ten phages with contractile tails and icosahedral heads were members of the Myoviridae family, and two phages with noncontractile tails belonged to the Siphoviridae family. Phage 11 represented a new species. It had an isometric head and a very long contractile tail with long wavy tail fibers and was one of the largest viruses known. The vast majority of 166 B. cereus strains (161, or 97%) isolated from food poisoning cases were typeable. Of 146 strains isolated from 18 outbreaks, 142 (97%) could be divided into 17 phage types. A good correlation, on the order of 80 to 100%, between phage types of strains isolated from suspected foods and those of strains isolated from stools of symptomatic patients was observed. Most Bacillus thuringiensis strains were also typeable, providing further evidence of the close relatedness of B. cereus and B. thuringiensis. This phage typing scheme can be a valuable epidemiological tool in tracing the origins of food poisoning caused by B. cereus.

Cellular fatty acid composition of Plesiomonas shigelloides.

The cellular fatty acid compositions of 29 strains of Plesiomonas shigelloides and 5 strains of Aeromonas hydrophila were studied. The cellular fatty acid compositions of all the Plesiomonas strains were identical and characterized by the presence of hexadecanoate (16:0) (33%), hexadecenoate (16:1) (28%), octadecenoate (18:1) (9%), and octadecanoate (18:0) (6%). The cellular fatty acid composition of A. hydrophila was similar to that of the Plesiomonas strains, except that the former contained an average of 25% 16:0, 29% 16:1, 12% 18:1, and 2% 18:0 acids compared with 33, 28, 9, and 6%, respectively, for the latter. The percentage ratios of 16:1 to 16:0 and 18:1 to 18:0 could be used to differentiate P. shigelloides from A. hydrophila. These ratios were 0.8 and 1.5 for the former and 1.2 and 6.0 for the latter.

Cellular fatty acid composition of Oerskovia species, CDC Coryneform groups A-3, A-4, A-5, Corynebacterium aquaticum, Listeria denitrificans and Brevibacterium acetylicum.

Twenty four strains representing eight species of gram positive yellow-pigmented rods (Oerskovia turbata, Oerskovia xanthineolytica, CDC Coryneform groups A-3, A-4, A-5, Listeria denitrificans, Corynebacterium aquaticum and Brevibacterium acetylicum) were divided into two major groups based on the relative amounts of 12 methyltetradecanoate (15:0a) obtained by capillary gas liquid chromatography. O. turbata, O. xanthineolytica, CDC groups A-3 and A-4, L. denitrificans and C. aquaticum were placed in the first group due to the presence of a higher percentage (29-47%) of 15:0a, than CDC group A-5 and B. acetylicum. The latter contained 2-6% of this fatty acid, and were placed in the second group. All species in the two groups except C. aquaticum and CDC group A-4, were further separated from each other based on the qualitative and quantitative differences in their fatty acid compositions. In addition, the eight strains of CDC group A-5 revealed four different patterns and were further divided into four subgroups. This study supports the importance of the composition of cellular fatty acids in differentiating some closely related organisms.

Development and application of monoclonal antibodies for the detection of cell infecting mycoplasmas.

Two hybridoma cell lines producing monoclonal antibodies (MAbs) to mycoplasmas were established by fusion of mouse myeloma and spleen cells obtained from mice immunized with whole cell Mycoplasma pneumoniae antigens. The MAbs designated as MYC-4 and MYC-9 bound to a single M. pneumoniae protein band with approximate molecular weights of 150,000. In dot-EIA both MAbs reacted with ten Mycoplasma spp., two serovars of Ureaplasma urealyticum and Acholeplasma laidlawii. The MAbs have great potential to be used as an antibody probe for the rapid screening of cell cultures and hybridomas for mycoplasmal contamination.

Rapid screening test for the diagnosis of rotavirus infection.

The early diagnosis of human rotavirus infection is essential for effective patient management and infection control. We report here a rapid, easy-to-perform, and inexpensive test for rotavirus detection. The viral RNA is extracted directly from the stools and electrophoresed on 1% agarose gels. Currently available immunoassays for routine diagnostic purposes are directed at the common group A-specific antigen. As reports become available on human gastroenteritis caused by the atypical or novel rotaviruses, this technique presents an added advantage in that it can detect both group A and non-group A rotaviruses.

Fatty acid profiles of Chlamydia using capillary gas chromatography.

Fatty acid profiles of purified elementary bodies of Chlamydia trachomatis (CT) serotypes D, G and L3 were investigated by gas liquid chromatography (GLC) utilizing three fused silica capillary columns of different polarities. CT serotype C and C. psittaci (CP) strain DD34 were investigated using one column only due to the lack of adequate quantities of purified material. Significantly similar fatty acid profiles were observed in the serotypes examined. However, based on the percentage ratio of 13-methyl tetradecanoate (i-15:0) to 12-methyl tetradecanoate (a-15:0), serotypes D and L3, with ratios of 0.18 and 0.19, respectively, could be differentiated from serotypes C and G with ratios of 1.3 and 1.5, respectively. CP demonstrated a ratio of 0.4, thus differentiating it from the CT serotypes examined. Fatty acids i-15:0 and a-15:0 were absent in uninfected McCoy cells. Results were significantly comparable in all three capillary columns. This study suggests that GLC could be used for identification and differentiation of Chlamydia serotypes.

Characterization of Escherichia coli serotype O157:H7.

A total of 174 strains of Escherichia coli serotype O157:H7 representing human isolates obtained from outbreaks and sporadic cases of hemorrhagic colitis, hemolytic-uremic syndrome, and nonbloody diarrheal illnesses as well as from asymptomatic carriers across Canada and the United States were examined. E. coli serotype O157:H7 possessed distinct biochemical markers, a 100% negative reaction for beta-glucuronidase and sorbitol, and a 100% positive reaction for raffinose and dulcitol; all strains otherwise were biochemically typical of E. coli. The vast majority (97%) of the strains were susceptible to commonly used antimicrobial agents. All strains produced readily detectable levels of Verotoxin; however, with polymyxin extraction, nearly 50% of the strains showed up to a 10-fold increase in the toxin level. None were found to mediate hemagglutination of human group A erythrocytes with or without D-mannose. The majority (approximately 70%) of the strains showed localized and diffuse adherence to HEp-2 cells and Henle 407 cells, and the adherence patterns were not very different from those observed among other E. coli strains. Twenty phage types were recognized, with phage types 1 and 2 accounting for 65% of the test strains. Plasmid analysis indicated three basic plasmid profiles: profile I was characterized by 68.7- and 4.2-megadalton (MDa) plasmids (62% of strains), profile II was characterized by 66.2- and 1.8-MDa plasmids (20% of strains), and profile III was characterized by a 62.5-MDa plasmid (18% of strains). A small number (19%) of the strains carried at least one additional plasmid over the basic complements, and these could be considered to constitute a miscellaneous category. None of the above-described characteristics of E. coli serotype O157:H7 could be directly correlated with one another, with the nature of infection, or with the geographical distribution of strains.

An outbreak of Trichophyton tonsurans dermatophytosis in a chronic care institution for the elderly.

A nosocomial outbreak of dermatophytosis caused by Trichophyton tonsurans var. sulfureum subvar. perforans is reported in a nursing home for the elderly. The outbreak affected six residents and persisted for nine months despite remedial medical and sanitary measures. In a survey designed to determine the potential role of fomites in disease transmission, 129 environmental sites were sampled. A high proportion (22.3%) of the samples yielded T. tonsurans, including samples from beds, floors, and washroom facilities. Methods for the control of dermatophyte outbreaks in chronic care institutions are discussed.

Comparison of Gen-Probe commercial kit and culture technique for the diagnosis of Mycoplasma pneumoniae infection.

The Gen-Probe rapid diagnostic system was compared with a culture method for the detection of Mycoplasma pneumoniae in clinical specimens. Of 116 clinical specimens, 103 (88.8%) yielded identical results. The relative sensitivity and specificity of the probe were both 89%. Rapid turnaround time and its sensitivity and specificity indicate that the probe test is a practical method for the rapid diagnosis of M. pneumoniae infections.

Mycoplasma pneumoniae infections in a rural setting in Canada.

Mycoplasma pneumoniae infection was monitored in patients with symptoms of acute respiratory tract infection in a village in southeastern Ontario from April 1983 to April 1984. M. pneumoniae was isolated from 51 (48%) of the 106 patients. The incidence began to increase in May 1983, reached a peak in July and declined to normal by mid-August. During the epidemic period M. pneumoniae was detected in 36 of the 43 symptomatic patients. The most prominent features of the outbreak were the considerable intrafamilial attack rate and the high frequency of pneumonia among infected patients. Treatment with tetracyclines and erythromycin reduced the duration of the illness and accelerated the resolution of symptoms.