Development of resistance to quinolones in five patients with campylobacteriosis treated with norfloxacin or ciprofloxacin

Development of resistance to nalidixic acid, norfloxacin and ciprofloxacin was observed in five patients with Campylobacter jejuni or Campylobacter coli infection. From all these patients nalidixic acid- and quinolone-susceptible strains were isolated initially, whereas after therapy with norfloxacin or ciprofloxacin strains resistant to these antibiotics were found. Campylobacter strains from the same patient always belonged to the same species and, with the exception of one case, showed identical rRNA gene restriction (rDNA) patterns. This indicates that double-infection with a susceptible and a resistant strain was not responsible for the phenomenon but rather that the infecting strain rapidly developed resistance following treatment.

Methods for the identification of DNA hybridization groups in the genus Aeromonas

Among the 269 substrates tested in assimilation tests we found some that may help in the identification of DNA hybridization groups in the genus Aeromonas. In addition, isoenzyme analysis and ribotyping seem to be accurate although not routine procedures that allow discrimination between genetic species.

Media and methods for isolation of aeromonads from fecal specimens. A multilaboratory study

An international multilaboratory study was conducted to establish the optimal combination of culture media, incubation time and temperature for recovery of aeromonads from stools using blood ampicillin (10 mg/l) agar (BAA), starch ampicillin (10 mg/l) agar (SAA), and cefsulodin irgasan novobiocin agar (CIN) with alkaline peptone water (APW) for enrichment. Optimal recovery of aeromonads (167/186) occurred using BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h) with APW (25 degrees C; 24 h) subcultured to BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h).

Multilocus enzyme analysis of the genus Aeromonas and its use for species identification

A total of 153 Aeromonas strains were analyzed by multilocus enzyme electrophoresis. All 11 genetic loci were polymorphic with three to 14 alleles per locus (average 6.55). The genetic diversity of each locus varied between 0.095 for indophenol oxidase and 0.881 for the fast variety of malic enzyme. Cluster analysis of the 122 enzyme types revealed a good correlation with taxonomic groupings as determined by DNA-DNA hybridization. In conjunction with biochemical analysis, as few as two enzymes may be sufficient for the identification of all species in the genus Aeromonas.

Biochemical and genetic characterization of autoagglutinating phenotypes of Aeromonas species associated with invasive and noninvasive disease

The genetic characteristics and biochemical and structural properties of a number of autoagglutinating (AA) strains of Aeromonas associated with invasive and noninvasive disease in humans and infections in animals and from environmental sources were investigated. Of 27 strains analyzed by multilocus enzyme typing and DNA hybridization studies, 25 (93%) were confirmed to belong to either hybridization group 1 (phenospecies and genospecies Aeromonas hydrophila) or 8 (phenospecies Aeromonas sobria; genospecies Aeromonas veronii). Further analysis of 19 of these strains indicated that four major groups could be identified on the basis of serologic and surface characteristics, protein and lipopolysaccharide composition, and virulence properties; these groupings held true regardless of the site of isolation or disease process involved. The major AA+ group identified was serogroup O:11, whose strains possessed an S layer, were resistant to the bactericidal activity of normal serum, and were pathogenic in mice. The results suggest a set of useful phenotypic and structural markers for identification of specific subsets of mesophilic Aeromonas involved in a wide range of infections in the animal kingdom.

[The problems of rapid diagnosis of Clostridium difficile as causative agent of antibiotic-associated pseudomembranous colitis]

This paper compares three common methods for the detection of Clostridium difficile, i.e. latex agglutination, culture and cytotoxic activity. The sensitivity of the latex agglutination test alone is 70%, of the culture 100% and of the cytotoxin test 66%. Specificities are 93, 96 and 100%, respectively. The latex agglutination has positive and negative predictive values of 58 and 96%; the respective values for the culture are 77 and 100%, for the cytotoxin assay 100 and 96%. Whereas all tests are fairly reliable for the exclusion of diarrhea associated to Clostridium difficile (CAD), the positive predictive values of latex agglutination and culture are too low. If one requests two positive test results for proof of CAD, about two third of all cases are detected by any combination of laboratory tests, while the specificity approaches 100%. We recommend that two of the three tests are performed; the choice is influenced by the possibilities of the laboratory.

[Salmonella gastroenteritis: causes, sequelae, therapeutic perspectives]

Enteric salmonella are the most frequently isolated pathogens of bacterial diarrhea in Switzerland. Since 1987, increasing numbers have been reported to the Federal Health Office. The causes of this rise in salmonellosis prevalence, which has been observed in a number of countries, are the high rates of contamination in different foods, mainly in poultry and eggs. It has been shown that the usual kinds of egg preparation are not suitable for the elimination of salmonella, which may also be found inside the egg-shells. The solution to this problem involves measures of veterinary epidemiology and food hygiene. The epidemiologic significance of the asymptomatic carrier is considered to be rather slight. However, prolonged excretion of salmonella repeatedly results in social and economic problems, because the carrier food handlers are excluded from work when and for as long as they are excreting salmonella. Current possibilities in antibiotic treatment for these and other salmonellosis patients are discussed.

rRNA gene restriction patterns and plasmid analysis as a tool for typing Salmonella enteritidis

We have evaluated the usefulness of ribosomal RNA gene restriction patterns and of plasmid analysis for the typing of Salmonella serotype enteritidis isolates. Strains were isolated from single patients excreting the organism for up to about 4 months, as well as from clusters of patients who had probably been exposed to the same source of infection. The sensitivity of ribosomal DNA (rDNA) analysis was dependent on the restriction enzyme used; of 14 different enzymes, only SmaI and SphI showed different rDNA patterns. Differences were detected between clusters, but all strains belonging to a given cluster showed identical rDNA patterns. In one single strain (isolated at day 66), we observed an SphI pattern that was not identical to that of the original isolate from the same patient. Strains were also typed by plasmid analysis. All strains harboured a plasmid of approximately 55 kb with identical restriction patterns. Smaller plasmids of 4.5 and 4.3 kb were isolated from all the strains belonging to one and two clusters, respectively. We have demonstrated that the analysis of rRNA genes is a sensitive and useful method for epidemiological typing of Salmonella serotype enteritidis, which can be complemented by analysis of plasmids if such structures are present.

In vitro activities of fleroxacin, cefetamet, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole, and amoxicillin-clavulanic acid against rare members of the family Enterobacteriaceae primarily of human (clinical) origin

Fleroxacin and cefetamet were evaluated in vitro against 38 infrequently encountered species (250 strains) of the family Enterobacteriaceae and compared with four established compounds. For all the strains tested, the fleroxacin MIC was less than or equal to 0.5 mg/liter, and for 98% of strains the cefetamet MIC was less than or equal to 8 mg/liter; even though the two new compounds did not quite reach the activities (on a weight-by-weight basis) of ciprofloxacin and ceftriaxone, respectively, they nonetheless clearly surpassed trimethoprim-sulfamethaxazole and amoxicillin-clavulanic acid. The very potent new oral compounds tested in this study appear to be promising for the treatment of clinically relevant infections due to uncommon species of Enterobacteriaceae.

Biochemical identification of Aeromonas genospecies isolated from humans

One hundred phenotypic characteristics were determined for 138 clinical and environmental Aeromonas strains. Cluster analysis revealed three major phenons equivalent to the A. hydrophila, A. caviae, and A. sobria groups, each of which contained more than one genospecies and more than one named species. An excellent correlation was found between phenotypic identification and classification based on DNA relatedness. DNA hybridization groups within each of the phenotypic groups were also separable by using a few biochemical characteristics. Key tests were production of acid from or growth on D-sorbitol (which separated DNA hybridization group 3 from groups 1 and 2 within the A. hydrophila phenogroup), growth on citrate (which essentially separated DNA hybridization group 4 from groups 5A and 5B within the A. caviae phenogroup), and growth on DL-lactate (which separated DNA hybridization group 1 from groups 2 and 3 within the A. hydrophila phenogroup as well as group 5A from groups 4 and 5B within the A. caviae phenogroup). All except one strain in the A. sobria phenogroup belonged to DNA hybridization group 8. DNA hybridization groups were not equally distributed among clinical and environmental isolates, suggesting that strains of certain DNA hybridization groups might be less virulent than others.

Automated analysis of 35-S-methionine labeled proteins by SDS-PAGE as a typing method in a suspected cluster of Serratia marcescens

During a nine-month period in 1986, we observed five ornithine decarboxylase-negative isolates of Serratia marcescens from four different patients. All isolates were identical in more than 50 biochemical parameters. Four isolates from three hospitalized patients were essentially identical in their susceptibility patterns to 12 antimicrobial agents. Analysis of 35-S-methionine labeled whole cell proteins by SDS-PAGE with the AMBIS system (Automated Microbiology System Inc., San Diego, CA) suggested that only three of these isolates were identical while the fourth hospital strain was more closely related to the isolate of a patient with no contact to the hospital. These results were confirmed by bacteriocin- and serotyping. We conclude that analysis of these protein patterns--which does not require special reagents - was an adequate method for typing S. marcescens.

Ribosomal RNA gene restriction patterns provide increased sensitivity for typing Salmonella typhi strains

To date, epidemiologic associations among strains of Salmonella typhi are based exclusively on phage typing, which may be of limited value if a common phage type is involved. Analysis of ribosomal RNA gene restriction patterns allows separation of most independently isolated strains of identical phage types. The sensitivity of the method is dependent on the restriction enzymes used to digest chromosomal DNA. It was highest for PstI, which separated 16 of 20 strains that belonged to 8 phage types including 3 untypable strains. Three strains differed in their phage types but had identical ribosomal RNA gene restriction patterns. Also, two pairs of strains indistinguishable by phage typing exhibited identical patterns; however, two of these strains were expected to be identical because they were isolated from two patients who were likely exposed to the same source. Ribosomal RNA gene restriction patterns appear to be stable. Thus, the method may complement phage typing and aid in further differentiation of strains.

CDC group HB-5 as a cause of genitourinary infections in adults

Isolates from five patients with genitourinary infections diagnosed over a 7-week period were identified as CDC group HB-5. The organisms caused clinical presentations of pelvic inflammatory disease in three women and urethritis in the only male in the series. The remaining patient received surgical treatment for a Bartholin gland abscess. Since the clinical and temporal presentations were remarkable and the questions of sexual mode of transmission and strain relatedness were of concern, the five strains were examined further by multilocus enzyme electrophoresis and ribosomal DNA typing. Overall, the five clinical isolates were more closely related to each other than to the control strains. This is the first report describing genitourinary infections caused by group HB-5. While the pathophysiology of group HB-5 infections remains to be fully elucidated, the possibility that this organism may be sexually transmitted deserves further study.

Bacterial molecular epidemiology based on a nonradioactive probe complementary to ribosomal RNA

The use of plasmid pKK3535 (a pBR322-derived plasmid containing a ribosomal RNA operon) is described for determining rRNA gene restriction patterns. The plasmid allowed the use of both radioactive as well as nonradioactive procedures and provided features that are necessary for the inclusion of internal and/or external standards that facilitate comparison of strains. The patterns generated are identical to those obtained by hybridization with 32P-labelled rRNA.

Aeromonas as a human pathogen

Although the first Aeromonas strain was described by Zimmermann as early as in 1890, it took 60 years until Caselitz established human pathogenicity of strains then called "Vibrio jamaicensis". Since then, and especially in the last 10 years, there have been increasing numbers of reports on different infections caused by members of the genus Aeromonas. These include sepsis; meningitis; cellulitis; necrotizing fasciitis; ecthyma gangrenosum; pneumonia; peritonitis; conjunctivitis; corneal ulcer; endophthalmitis; osteomyelitis; suppurative arthritis; myositis; subphrenic abscess; liver abscess; cholecystitis and/or ascending cholangitis; urinary tract infection; endocarditis; ear, nose, and throat infections; balanitis; etc. The role of Aeromonas in gastrointestinal disease is very controversial. Increasing epidemiological data suggest that these organisms play a major role in enteric infections, but so far enteropathogenicity has not been demonstrable in experiments where volunteers were given high numbers of Aeromonas possessing different virulence factors. Virulence factors include hemolysin(s), enterotoxin(s), hemagglutinins, invasivity, and others; but these are not found more frequently in strains isolated from patients with diarrhea than from healthy controls. Whether there is a correlation between species and disease remains to be elucidated and requires more information about the taxonomy of this genus.

Multilocus enzyme electrophoresis of Clostridium argentinense (Clostridium botulinum toxin type G) and phenotypically similar asaccharolytic clostridia

Twenty-three strains of Clostridium argentinense, C. subterminale, C. hastiforme, and other phenotypically similar asaccharolytic clostridia recently placed in seven DNA hybridization groups were compared by multilocus enzyme electrophoresis. The three nontoxigenic strains of C. argentinense were most closely related to the toxigenic strains of this species. All nine toxigenic strains of C. argentinense belonging to a single DNA hybridization group had identical enzyme types on the basis of nine enzymes. All other strains except for two derived from the type strain of C. subterminale were differentiable. Overall, there was excellent agreement between DNA relatedness and multilocus enzyme electrophoresis results.

Evaluation of a small "conventional" identification system for fermentative gramnegative rods using a computerized data base

A small "conventional" identification system consisting of six tubed media totalling eleven reactions was used to identify 467 strains of Enterobacteriaceae, 15 strains of Aeromonas sp., and 3 strains of Plesiomonas shigelloides. The system identified 371 strains (76.5%) correctly to maximum identification (species or genus) level and an additional 13 strains (2.7%) to genus level where species level identification would have been possible. Ninety strains (18.6%) were not identified. Only 11 strains (2.3%) were misidentified. The system is inexpensive compared with commercial systems and can be used for primary identification of fermentative gramnegative bacteria in a clinical microbiology laboratory. It comes with a computerized data base in the form of an identification manual.

Problems in identification of Campylobacter jejuni associated with acquisition of resistance to nalidixic acid

In a patient with campylobacteriosis, we observed development of resistance to nalidixic acid and norfloxacin under adequate treatment with the latter antibiotic. Isolates before and after treatment differed in their total protein profile but were otherwise identical with respect to enzymatic activity, serotype, crude membrane protein profiles, and other phenotypic characteristics.

[Aeromonas spp. as pathogens in human infections: diagnosis and clinical significance]

Aeromonads have been described as causative agents in a wide variety of infections in immunosuppressed as well as in immunocompetent patients. It is still controversial whether or not some or all three currently recognized species have to be considered as enteropathogenic. Clinical and epidemiological data are incomplete and contradictory although laboratory diagnosis does not cause real problems.

Isolation frequency of Aeromonas species in relation to patient age

Over a period of 18 months Aeromonas spp. were isolated from stool specimens of 116 patients (total isolation frequency 1.6%). Isolation rates in children up to ten years of age were significantly higher only for Aeromonas caviae as compared to other age groups. Additional data are needed to assess the clinical significance to these findings.

[Resistance patterns in Shigella]

Diarrhea is the most common health problem in travelers to tropical countries. Shigellae are not the primary cause but often provoke clinically relevant diseases that call for treatment. Therefore, we have analyzed resistance patterns in all Shigella strains isolated at this department over 1 1/2 years. Of 107 isolates 77% were resistant to tetracycline, 33% to trimethoprim-sulfamethoxazole, 31% to ampicillin, and only 2% to nalidixic acid. Differences in resistance patterns for isolates of different geographical origins were marginal. The small number of strains resistant to nalidixic acid (2/107) suggests that agents inhibiting DNA gyrase may be useful for self-administered treatment during travel as well as upon return. Controlled clinical trials, however, are still lacking.

The nucleotide sequence of two homogeneic Drosophila melanogaster tRNATyr isoacceptors: application of a rapid tRNA anticodon sequencing method using S-1 nuclease

The nucleotide sequence of the two major Drosophila melanogaster tRNATyr isoacceptors was determined to be pC-C-U-U-C-G-A-U-A-m2G-C-U-C-A-G-D-D-G-G-acp3 U-A-G-A-G-C-m2(2)G-G-psi-G-G-A-C-U-G/Q-psi-A-m1G-A-Um-C-C-A-U-A-G-m7 G-D-C-G-C-U-G-G-U(T)-psi-C-A-m1A-A-U-C-C-G-G-C-U-C-G-A-A-G-G-A-A-C-C-AOH . The two isoacceptors differ by the presence of a G or a Q in the wobble position. Both contain a partial modification in position 54 (U/T). Thus, these tRNAs are transcribed from a single gene (or many genes with identical sequences). A fast and sensitive postlabeling method for sequencing tRNA anticodons is described. Nuclease S-1-treated tRNA is labeled with 5[32P]-pCp using T-4 RNA ligase. The tRNA fragments are then separated on 7 M urea/20% PAA gels. After autoradiography the RNA is eluted and digested with T-2 RNase. The nature of the labeled nucleotides is determined by two-dimensional thin-layer chromatography. The same method can be used to determine the 5' sequence of a tRNA by 3' labeling 5' tRNA halves with 5[32P]-pCp and subsequent chemical sequencing.

Differentiation of Kluyvera cryocrescens from Kluyvera ascorbata by irgasan susceptibility testing

From the faeces of a diarrhoeic patient, we isolated a strain of Kluyvera ascorbata on cefsulodin-irgasan-novobiocin (CIN) agar, a highly selective medium used for Yersinia enterocolitica. Since no selective media have been described for Kluyvera spp., we tested 5 strains each of K. ascorbata and K. cryocrescens for their ability to grow on CIN agar. K. ascorbata exhibited an inhibition on CIN of less than 10% CFU compared to blood agar, whereas K. cryocrescens did not grow at all even with inocula as high as 10(5) CFU per plate. This phenomenon correlated very well with MIC values to irgasan, which were greater than 128 mg/l for K. ascorbata and less than or equal to 0.25 mg/l for K. cryocrescens. No significant differences between the two species were observed for the other two antibiotics contained in CIN. This phenotypic character has been used to differentiate 18 strains belonging to either species on the basis of a simple disk test: with disks containing 5, 25, or 125 micrograms irgasan, K. ascorbata never showed zones of inhibition, whereas K. cryocrescens produced zones of greater than or equal to 15, greater than or equal to 21.5 and greater than or equal to 25.0 mm in diameter, respectively.

Growth of Aeromonas spp. on cefsulodin-Irgasan-novobiocin agar selective for Yersinia enterocolitica

Twenty-eight strains of Aeromonas spp. were analyzed for their ability to grow on two different kinds of cefsulodin-Irgasan (triclosan; Ciba-Geigy AG, Basel, Switzerland)-novobiocin (CIN) agar containing 15 or 4 mg of cefsulodin per ml and on inositol-bile salts-brilliant green (IBB) agar. Relative to blood agar, 68% of the strains were inhibited by more than 2 logs (i.e., less than 1% growth) at 37 degrees C (39% at 25 degrees C) on CIN I (high cefsulodin concentration), 7% were inhibited at either temperature on CIN II (low cefsulodin concentration), 4% were inhibited on IBB agar at 37 degrees C, and none were inhibited on IBB agar at 25 degrees C. These results reflect the MICs of cefsulodin on CIN Base: the MIC for 50% of the strains was 8 mg/liter at 37 and 25 degrees C, and the MICs for 90% of the strains were 16 mg/liter at 37 degrees C and 64 mg/liter at 25 degrees C. The MICs of Irgasan and novobiocin were far beyond the concentrations used in CIN media. We argue that CIN agar containing 4 mg of cefsulodin per ml (CIN II) can be used for the simultaneous detection of Aeromonas spp. and Yersinia spp.

Aeromonas caviae: an enteric pathogen?

Of the Aeromonas spp. isolated routinely in our laboratory from human feces, about two thirds represent Aeromonas caviae. In contrast to Aeromonas hydrophila and Aeromonas sobria, this species has been considered to be of little enteropathogenic significance due to the absence of known virulence factors. The clinical data presented here suggest a clinical significance of A. caviae, at least in some cases. As yet nothing is known about the pathogenic mechanisms involved.

Evaluation of a rapid, reliable, and inexpensive screening test for the serological diagnosis of human brucellosis

In many laboratories the serological diagnosis of brucellosis is based on a tube agglutination test requiring incubation for two days and therefore causing delay in reporting of results. A slide agglutination test using an acidified, rose Bengal colored antigen that can be read after only 4 min was evaluated for its usefulness as a screening test for the presence of agglutinins in human sera. In sera of patients with culturally proven brucellosis or serological evidence for active infection the sensitivity of the slide agglutination test was 100%. Of 97 tube agglutination-negative sera none was positive in the slide test. From these results it was concluded that sera can be tested by the slide agglutination test which is quicker, easier to perform, and less expensive than the tube agglutination test. If positive, it is followed by a tube agglutination test which gives quantitative information and is necessary to follow the course of an infection.

Corynebacterium group JK peritonitis in patients on continuous ambulatory peritoneal dialysis

Corynebacterium group JK is described as the aetiologic agent of a second episode of peritonitis which occurred after a period of antibiotic treatment for likely endogenous peritonitis. Inclusion of vancomycin is suggested for treatment of continuous ambulatory peritoneal dialysis (CAPD) peritonitis in patients colonized by these multiresistant bacteria.

Performance of two four-hour identification systems with atypical strains of Enterobacteriaceae

Two four-hour systems (Rapid 20E and Micro-ID) for identification of Enterobacteriaceae were evaluated using 66 strains isolated from clinical specimens which could not be identified by conventional methods. API 20E was used as reference method. Both systems had an acceptable identification rate (84.8% for Rapid 20E and 74.2% for Micro-ID). After referral to API's computer facilities the identification rate of Rapid 20E rose to 92.4%. Micro-ID incorrectly identified 16.7% of the strains and Rapid 20E only 1.5%. On the other hand, no identification was achieved in 13.6% of the strains using Rapid 20E versus 6% using Micro-ID. On the basis of these findings Rapid 20E is considered the more suitable system for the rapid identification of Enterobacteriaceae strains which cannot be identified by conventional methods.

The genes coding for 4 snRNAs of Drosophila melanogaster: localization and determination of gene numbers

Four small nuclear RNAs (snRNAs) have been isolated from Drosophila melanogaster flies. They have been characterized by base analysis, fingerprinting, and injection into Axolotl oocytes. The size of the molecules and the modified base composition suggest that the following correlations can be made: snRNA1 approximately U2-snRNA; snRNA2 approximately U3-snRNA; snRNA3 approximately U4-snRNA; snRNA4 approximately U6-snRNA. The snRNAs injected into Axolotl oocytes move into the nuclei, where they are protected from degradation. The genes coding for these snRNAs have been localized by "in situ" hybridization of 125-I-snRNAs to salivary gland chromosomes. Most of the snRNAs hybridize to different regions of the genome: snRNA1 to the cytological regions 39B and 40AB; snRNA2 to 22A, 82E, and 95C; snRNA3 to 14B, 23D, 34A, 35EF, 39B, and 63A; snRNA4 to 96A. The estimated gene numbers (Southern-blot analysis) are: snRNA1:3; snRNA2:7; snRNA3:7; snRNA4:1-3. The gene numbers correspond to the number of sites labeled on the polytene salivary gland chromosomes.

The nucleotide sequence of histidine tRNA gamma of Drosophila melanogaster

The nucleotide sequence of D. melanogaster histidine tRNA gamma was determined to be: pG-G-C-C-G-U-G-A-U-C-G-U-C-psi-A-G-D-G-G-D-D-A-G-G-A-C-C-C-C-A-C-G-psi-U-G-U-G- m1G-C-C-G-U-G-G-U-A-A-C-C-m5C-A-G-G-U-psi-C-G-m1A-A-U-C-C-U-G-G-U-C-A-C-G-G-m5C -A-C-C-AOH. An additional unpaired G is found at the 5' end, and the T in the TpsiC loop is replaced by a U.

The nucleotide sequence of glutamate tRNA4 of Drosophila melanogaster

The nucleotide sequence of Drosophila melanogaster glutamate tRNA4 was determined to be: pU-C-C-C-A-U-A-U-G-G-U-C-psi-A-G-D-G-G-C-D-A-G-G-A-U-A-U-C-U-G-G-C (m) -U-U-U-C-A-C-C-A-G-A-A-G-G-C-C-C-G-G-G-T-psi-U-C-G-A-U-U-C-C-C-G-G-U-A-U-G-G-G-A-A-C-C-AOH. A partial modified C is found at position 32 in the anticodon loop.

The nucleotide sequence of phenylalanine tRNA2 of Drosophila melanogaster: four isoacceptors with one basic sequence

The nucleotide sequence of Drosophila melanogaster phenylalanine tRNA2 was determined to be: pG-C-C-G-A-A-A-U-A-M2G-C-U-C-A-G-D-D-G-G-G-A-G-A-G-C-m22G-psi-psi-A-G-A-C(m)-U-Gm-A-A-mlG-A-psi-C-U-A-A-A-G-m7G-U(D)-C-C-C-C-G-G-T-psi-C-A-mlA-U-C-C-G-G-G-U-U-U-C-G-G-C-A-C-C-AOH. Upon RPC-5 chromatography at pH 3.8 tRNA2Phe can be separated into four isoacceptors due to the partial modifications in positions 32 and 47. Thus the posttranscriptional modification of tRNA2Phe transcribed from one gene (or many genes with identical sequences results in four isoacceptors with the same basic sequence.