Untypable Isolates Research Articles

Capsular variation in experimental strains ofHaemophilus influenzae

This study sought to demonstrate that clinically untypable strains of Haemophilus influenzae are derivable from previously capsulated ones. Penicillin-induced forms were employed to explore in vivo and in vitro a possible mechanism of the reversible cycle vegetative to L-phase revertant. Normal H. influenzae type b (Rab), capsule-deficient strain ATCC 9333, and experimental L-phase and its revertants were used in this investigation. Capsular antigens, polyribose phosphate (PRP) content of each strain was assayed by orcinol and rocket immunoelectrophoretic methods. Intra- and inter-strain PRP differences were statistically analysed. Strain differences between in vivo and in vitro passaged extracts of strain 9333 and 9333 were significant (t-test P less than 0.01). There were also significant differences in vivo and in vitro between penicillin-treated, L-phase infected mouse isolates and penicillin-free, L-phase infected mouse isolates; and also between penicillin-treated, L-phase infected mouse isolates and revertant Rab infected mouse isolates (Mann-Whitney U-test P less than 0.02, P less than 0.01, respectively). These findings suggest that untypable isolates of H. influenzae are derivable from otherwise capsulated strains, depending on decapsulating factors in the microenvironment. Clinical implications of the findings are discussed.

福岡県の養蚕農家におけるＢａｃｉｌｌｕｓ ｔｈｕｒｉｎｇｉｅｎｓｉｓの分布

A total of 124 crystalliferous sporeformers were isolated from the silkworm litters of 8 sericultural farms out of 38 farms of Fukuoka Prefecture, Japan. Most isolates were found to belong to Bacillus thuringiensis serotypes 3a: 3b (subsp. kurstaki), 4a: 4b (subsp. sotto or subsp. dendrolimus), 4a: 4c (subsp. kenyae), 7 (subsp. aizawai), 8a: 8b (subsp. morrisoni), 9 (tolworthi), and 19 (subsp. tochigiensis). Of these 7 serotypes, serotypes 3a: 3b, 4a: 4c, and 7 were predominantly detected. No concentrated occurrence of this bacterium was observed in any particular region. Coexistence of two different serotypes was evident in 3 sericultural farms. Three H serotypes and one untypable strain were simultaneously isolated from one farm. Most isolates were toxic to the silkworm larvae, Bombyx mori. For mosquito larvae, Aedes aegypti, serotype 7 isolates were more toxic than the isolates of the other serotypes. The above untypable isolate was nonmotile and produced large parasporal inclusions nontoxic to larvae of the silkworm and the mosquito. The four isolates belonging to serotype 19 produced spherical parasporal inclusions. These isolates were nontoxic to the silkworm but showed low toxicity to the mosquito.

Antigenic relationships among some bovine rotaviruses: serum neutralization and cross-protection in gnotobiotic calves.

A method was further developed to screen non-tissue-culture-adapted bovine rotaviruses for serotype, using a neutralization test with infectious fecal rotavirus. One of those rotaviruses (B223) which was not blocked by antiserum to the neonatal calf diarrhea virus (NCDV) serotype was then adapted to cell culture in the presence of the antiserum for two or more passages and hyperimmune antiserum to this isolate had a 60-fold-higher homologous neutralization titer than with the NCDV serotype rotavirus. Seventy-three isolates were serotyped and eight (11%) were not of the NCDV serotype (bovine rotavirus serotype I). Of these eight, five belonged to the new bovine rotavirus serotype II and three were not typed, indicating the existence of one or more further serotypes. Cross-protection studies in gnotobiotic calves showed that cross-protection only occurred between rotaviruses of the same serotype, and even a minor serotype difference was sufficient for the calves to show a lack of cross-protection. The serotypes (I and II and the three untyped isolates) also showed differences in the rate of migration in polyacrylamide gel electrophoresis of some of their RNA segments (no. 4, 6, 7, 8, 9, 10), indicating that they were of different electropherotypes.

A survey of mycoplasma infections in domestic poultry

A survey of mycoplasma infections of chickens, turkeys and ducks was made on tissues from a variety of sources and birds of various ages, and from pipped and dead-in-shell turkey embryos. The tissues examined consisted mainly of respiratory tissue and the cloaca and contents and also a small number of joint lesions and other tissues. From chickens, mycoplasmas were isolated from a total of 138 tissues with Mycoplasma gallisepticum in preponderance. This was followed by M gallinarum, untyped organisms, M synoviae and a number of other mycoplasmas and Acholeplasma laidlawii. From turkeys, poults and embryos, mycoplasmas were recovered from 164 tissues with M meleagridis in preponderance. This was followed by M gallisepticum, serovar I, M synoviae and a number of other species including untyped isolates. From ducks, M gallisepticum and M anatis were recovered in equal numbers. Mycoplasma infections with more than one species occurred in the same tissue in all species of stock but especially in turkeys.

BACTERIOPHAGE TYPING OF STAPHYLOCOCCI ISOLATED FROM FOODSTUFFS AND FOOD HANDLERS IN TEHRAN

Studies were done to assess contamination of 3247 samples of foods and food handlers with coagulase-positive staphylococci. Food specimens were collected from retail shops and a Tehran milk pasteurizing plant; in addition 510 food handlers of different professional groups were examined. Three swabs for bacteriological examination were randomly collected from nose, hands, and throat. Of samples tested for coagulase-positive staphylococci, 28.02% were positive and almost half of them were obtained from foodstuffs. Of 546 isolates that were phage typed, we found that group III predominated in the nose and cream cake, while group II was more prevalent in raw cream, throat, and hands. Although group IV was not prominent, nose and hands yielded 3 and 1 positives, respectively. Untypable isolates comprised about 47.2% with most from hands and nose, 61.7 and 60.5%, respectively, and the least from raw cream, 33.3%.

Vibrio parahaemolyticus gastroenteritis in Maryland: laboratory aspects.

Vibrio parahaemolyticus was the etiological agent in three food-related epidemics of gastroenteritis in Maryland, during August 1971. These outbreaks involved crab food products. Fifteen isolates of V. parahaemolyticus were made which included 11 from patients and 4 from foods. Serotype 04:K11 was the cause of the outbreaks. It was recovered from patients in each outbreak and gave a positive Kanagawa reaction, an indication of enteropathogenicity. Other patient isolates included types 03:K30, 03:K33, and an untypable isolate, all of which were Kanagawa negative. Food isolates included serotypes 03:K30, 02:K28, and two untypable isolates, all of which were Kanagawa negative. The outbreaks reported in this paper constitute the first confirmed foodborne epidemics due to V. parahaemolyticus in the United States. Methods for the isolation and identification of V. parahaemolyticus are presented, including a procedure for the simple conversion of conventional laboratory media into suitable culture media for this halophilic organism.

Vibrio parahaemolyticus Gastroenteritis in Maryland: Laboratory Aspects

Vibrio parahaemolyticus was the etiological agent in three food-related epidemics of gastroenteritis in Maryland, during August 1971. These outbreaks involved crab food products. Fifteen isolates of V. parahaemolyticus were made which included 11 from patients and 4 from foods. Serotype 04:K11 was the cause of the outbreaks. It was recovered from patients in each outbreak and gave a positive Kanagawa reaction, an indication of enteropathogenicity. Other patient isolates included types 03:K30, 03:K33, and an untypable isolate, all of which were Kanagawa negative. Food isolates included serotypes 03:K30, 02:K28, and two untypable isolates, all of which were Kanagawa negative. The outbreaks reported in this paper constitute the first confirmed foodborne epidemics due to V. parahaemolyticus in the United States. Methods for the isolation and identification of V. parahaemolyticus are presented, including a procedure for the simple conversion of conventional laboratory media into suitable culture media for this halophilic organism.

The effect of mitomycin C on the pyocine typing patterns of hospital strains of Pseudomonas aeruginosa.

With a view to shortening the time required for pyocine typing and reducing the proportion of untypable isolates, the effect of inducing strains of Pseudomonas aeruginosa by mitomycin C was studied. Detailed experiments with two strains showed that mitomycin C enhanced pyocine production by a typable strain and allowed formation of pyocine by an untypable strain. Maximal production of pyocine was achieved using mitomycin C in a concentration of 0.5 μg/ml.Three hundred and thirty-six isolates of P. aeruginosa which had been typed by Gillies and Govan's method were retyped after induction by mitomycin C. Induction and typing were performed on the same agar plate, and a 6-h incubation period at 32 °C was found sufficient for pyocine production. A similar number of typing patterns were found by both methods, but 154 isolates showed a different pattern after induction, and 23 of 38 previously untypable strains became typable. The typing patterns observed after induction were reproducible, and at least as stable epidemiologically as those obtained without induction.

Somatic antigens of Streptococcus group E. II. Separation and a partial physicochemical characterization.

Antigenic extracts of Streptococcus group E (SGE) were subjected to fractional ethanol precipitation, block (preparative) electrophoresis, and gel filtration for the purpose of separating the type antigen from the group antigen. Ethanol precipitation was ineffective in separating the substances. Block electrophoresis yielded serologically pure group antigen and a mixture of type and group antigen. Serologically pure type antigen was obtained by gel filtration. In some cases, pure group antigen was also recovered; in others, it was contaminated with type antigen. Gel filtration column effluents of antigenic extracts of SGE serotypes, I, II, III, IV, V and "untypable" isolates, collected from the region in which type antigen was eluted, were studied by paper chromatography and infrared spectrophotometry in an effort to develop a nonserological means of detecting type antigen. Hydrolysates of type antigens or suspect type antigens of serotypes I through V contained l-rhamnose, d-glucose, and several unidentified substances. d-Galactose also was present in hydrolysates of serotypes III and V. Untypable isolates and negative controls contained traces of d-glucose only. The data suggested that serotypes I through V contained a type antigen and that the untypable isolates were devoid of type antigen. Infrared absorbance spectra seemed to support the paper chromatography data.