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H Milch

Publications and source records attributed to H Milch.

At least 37 records · Page 2Linked to original sources
PubMed1990

Epidemiology of Salmonella derby strains isolated from swine, pork and pork products.

A total of 35 Salmonella derby strains, isolated from 6 types of samples of porcine origin from 9 different places in Hungary were examined for their characteristics. Thirty-two strains (91%) were of phage type 25, 2 (6%) of phage type 15 and 1 (3%) of phage type 58. Colicin production was observed in 3 (9%) strains. Five strains (14%) were found to be resistant to tetracycline (Tc). The strains harboured plasmids of 2.2, 2.4, 3.4, 4.2 and 72 Md. The 72 Md plasmid appears to be characteristic of S. derby and possibly encodes Tc resistance. The 72 Md plasmid belonged partly to incompatibility (Inc) group I1, while the other plasmid of the same size belonged to Inc. group B. The findings suggest that healthy salmonella carrier pigs carried the infection from the farm to the abattoir. Slaughtering of infected pigs may have led to contamination of the carcasses and, thereafter, that of the pork and pork products.

Animals↗
PubMed1990

In vitro and in vivo (LD50) effects of human lactoferrin on bacteria.

The in vitro and in vivo effects of human lactoferrin (LF), apoLF, iron saturated LF and of different iron containing compounds (ferric chloride, ferric sodium citrate) were studied on Escherichia coli, Salmonella typhi-murium and Pseudomonas aeruginosa reference and wild-type strains with well-defined virulence markers (i.e. enterochelin, aerobactin production). LF exert in vitro antibacterial effect, and iron-free Vogel-Bonner medium proved to be suitable for its determination. The effect of intraperitoneally administered LF could not be evaluated because of its aspecificity, as any treatment (e.g. saline, Ringer solution) before bacterial challenge activated macrophages. In contrast to the in vitro results, intramuscular challenge failed to inhibit bacterial growth in vivo, as siderophores produced by bacteria were able to acquire lactoferrin-bound iron. LF treatment, like iron addition, enhanced the virulence of bacteria in mice, whereas apoLF - using iron present in the body fluids - turned to LF being unable to acquire siderophore-bound iron from bacteria. These findings do not support the literary view that LF would be useful as an antimicrobial drug.

Animals↗
PubMed1990

Association of virulence markers with animal pathogenicity of Escherichia coli in different models.

Employing chicken and several strains of mice, different routes (intraperitoneal, subcutaneous) of infections and isogenic pairs of strains, association of virulence markers with animal pathogenicity was studied in Escherichia coli. Mouse virulence of avian strains was less significant than the lethality for chicks of human strains. LD50 in various animals did not differ significantly. Strains with antigen K1 were more virulent for mice than their K1- derivatives. Loss of haemolysin (Hly), mannose resistant haemagglutinating capacity or antigen K5 less markedly decreased the virulence. As opposed to other virulence factors, increased virulence of K1+ strains could also be demonstrated in mouse sepsis assay based on bacterial counts in the liver. Loss of Hly alone did not influence the persistence in the liver, however, these strains killed less mice. Aerobactin acts together with other factors, it is not per se a virulence factor. In organotropic experiments 19 strains out of 36 belonging to serotypes O7:K1:H-, O18:K1:H-, O78:H- and spontaneously agglutinable K1+ cultures, caused ophthalmitis with purulent discharge, and 4 out of 22 strains that belonged to serotype O78:H- induced uncoordinated movement of mice. Because of its special organotropic affinity to the brain and as it caused two epidemics of meningitis among newborns in Hungary, serotype O78:H- has a special pathogenic property and differs from other O78 strains that were isolated in other countries.

Animals↗
PubMed1989

The frequency of aerobactin production and its effect on the pathogenicity of human Escherichia coli strains.

A total of 981 human Escherichia coli strains (including 632 strains isolated between 1979 and 1983 and 349 strains isolated in 1987) was examined for aerobactin production by biological qualitative test. Aerobactin positivity was found in 55.1% and 47.3%, respectively, in the two groups of strains, while enterochelin was produced nearly by 100% of the strains. Aerobactin production was significantly more frequent than the average among blood and CSF strains samples and serogroup O2 and O6 strains. Aerobactin was more frequent among isolates with K1 or K5 antigens and producing haemolysin and mannose-resistant haemagglutination than among the ones lacking these virulence factors. A strict correlation was found between the pathogenicity in mouse following intraperitoneal infection and the frequency of aerobactin production. The distribution of the LD50 values of the aerobactin positive strains was shifted towards the lower values comparing to the aerobactin negative ones, proving statistically the effect of aerobactin in the increase of pathogenicity.

Drug Resistance, Microbial↗
PubMed1987

Adsorption to Al(OH), gel of Escherichia coli is correlated with O and K antigens and with type of extraintestinal infection.

Living suspensions of 89 Escherichia coli strains were tested for adsorption to Al(OH)3 gel in the presence of phosphate ions. On the basis of AC50 (phosphate molarity inhibiting 50% adsorption of the strain examined), E. coli strains could be classified into two main groups. Forty-three strains belonged to group 1 (AC50, 0.01-0.04), and 42 of them fell into serogroups O1, O2, O5, O7, O18ac, O83 or were spontaneously agglutinable. One strain in group 1 was exceptional as it had antigen O4. Of these 43 strains 33 had K antigen K1. Serogroup distribution of 46 group 2 strains (AC50, 0.001-0.009) was O2, O4, O6, O18ac, O75 and O78; 20 out of 46 possessed antigen K5. No correlation existed between H antigens or haemagglutinating capacity and AC50 of the strains. A close correlation was shown between AC50 pattern and the two main pathogenecity groups (i.e. "newborns' meningitis" and "sepsis and organotropic diseases") on one hand and between AC50 pattern and O, K serotypes on the other. The findings indicate that these E. coli strains with identical markers had a clonal connection.

Adsorption↗
PubMed1987

Virulence factors of Escherichia coli. IV. Association in Escherichia coli of LD50 with haemolysin production, haemagglutinating capacity, antigens K1, K5 colicinogenicity and pathogenicity.

Haemolysin production (HLY), mannose resistant haemagglutinating activity (MRA), presence of antigens K1 and K5 and colicinogenicity (Col) were compared with LD50 for mice in 663 Escherichia coli strains, including 281 faecal, 129 urinary and 253 other extraintestinal isolates. Those isolates that LD50 value fell into less than or equal to 10(6) LD50 category were arbitrarily termed highly virulent (HV) and those which belonged to greater than or equal to 10(7) LD50 category were considered avirulent (AV). HV isolates occurred significantly more frequently (58%) among strains from different extraintestinal samples than from faeces (14%) or urine (16%). The incidence of HV strains was significantly higher in patients with sepsis (43%) or meningitis (100%) than in patients with enteritis (20%), urinary tract infections (UTI, 16%) or in healthy subjects (28%). The incidence of HV strains in the most frequent (O1, O2, O4, O6, O7, O18, O75) serogroups was significantly higher (60%) than in others (10%). Strains with different virulence markers (HLY, MRA, K1, K5, Col) belonged significantly more frequently to the HV group than those which failed to have these markers (44 vs 27%, 51 vs 25%, 83 vs 17%, 78 vs 27%, 52 vs 16%, respectively). Important role of antigen K1 playing in pathomechanism of meningitis was confirmed by data of analysis according to which significant difference was revealed in the incidence of HV strains between groups of isolates with MRA+K1+ (71%) and MRA+K1- (44%, p less than 0.02), or between groups of isolates with MRA+K1- and MRA-K1+ (91%, p less than 0.001). Moreover there were significant differences in the incidences of HV strains in K1+Col- (73%) and K1-Col+ (29%, p less than 0.001), and in K1+Col+ (86%) and K1-Col+ (29%, p less than 0.001) groups. Further evidence was given by those data that there were no significant differences between groups of HV strains with MRA+K1+ and MRA-K1+ (p greater than 0.05) or with K1+Col+ and K1+Col- (p greater than 0.1) properties. Isolates that possessed simultaneously two of MRA, HLY, Col markers were more pathogenic in LD50 assay than those that had one or the other of these markers alone. Strains in serogroup O18 killed mice significantly more frequently than those of other serogroups independently of having any virulence factor, suggesting that bacteria in serogroups O18 must have some special virulence other than K1, Col, MRA or K5. MRA+HLY+ HV strains occurred frequently in extraintestinal diseases (42%) supporting the preconception that these properties play an important role also in the pathomechanism of extraintestinal infections other than UTI.(ABSTRACT TRUNCATED AT 400 WORDS)

Antigens, Bacterial↗
PubMed1987

Antibiotic resistance and plasmid profiles of Escherichia coli and Klebsiella isolated from in-patients receiving prolonged antibiotic therapy.

Distribution by serogroup, phage type, colicin production, colicin type, sensitivity to antibiotics and plasmid characteristics of 74 Escherichia coli and 11 Klebsiella strains isolated from hospitalized patients receiving prolonged antibiotic therapy indicated that the infections were not associated with the hospital environment. Resistance was tested to 26 antibiotics, some of them being not generally used in therapy; 30 strains were resistant to 4 to 17 antibiotics. There was a significant difference in the antibiotic resistance of strains derived from patients with urinary-tract infections (UTI) and with leukaemia (LP). As compared to the UTI group, among E. coli strains in the LP group the frequency of multiple resistance was significantly higher, the MIC values were higher and R-plasmids were more frequent. Out of 30 multiple resistant E. coli strains 27 were R-plasmid carriers. Three different kinds of plasmid profile were shown in more than one strain (2 out of 10 UTI strains and 3 and 2 out of 10 LP strains). The rest of the isolates differed in plasmid profile from these and from one another; the presence of "epidemic plasmid" was not demonstrated. Plasmid epidemiological examinations may forecast the efficacy of an antibiotic or of a group of antibiotics.

Colicins↗
PubMed1986

Virulence factors of Escherichia coli. III. Correlation with Escherichia coli pathogenicity of haemolysin production, haemagglutinating capacity, antigens K1, K5, and colicinogenicity.

A total of 1156 Escherichia coli strains including 489 faecal, 384 urinary, 283 other extraintestinal isolates was compared for haemolysin production (Hly), mannose resistant haemagglutinating activity (MRA), presence of antigens K1 and K5 and colicinogenicity (Col). K1 capsule which was demonstrated only in a few serogroups (O1, O2, O7, O18) occurred more frequently among extraintestinal (32.1%) than among faecal (4.3%) or urinary (7.3%) isolates. In the incidence of antigen K5 there was no difference between faecal and urinary (3.3%; 3.1%) or between urinary and other extraintestinal (5.3%) isolates belonging mainly to serogroups O2, O6, O18 and O75. Col+ isolates occurred frequently in all samples (23.5% of faecal, 31.7% of urinary and 43.4% of other extraintestinal strains), they being significantly more frequent in serogroups O1, O2, O7, O18 than in others. A close association existed between K1+ and Col+ properties, mainly (24.4%) among strains isolated from extraintestinal sources other than urine. The frequent coexistence of K1+ and Col+ in serogroups O1, O2, O7, O18 offers a further explanation for the extraintestinal pathogenicity of these serogroups. Neither Hly+ and K1+, nor Hly+ and Col+ were associated. MRA+ and K1+ correlated mainly in serogroups O1, O2 but never occurred simultaneously in serogroup O18. Connection between MRA+ and Hly+ was not associated with other virulence factors (K1, Col). The results showing a close connection among certain serogroups (O1, O2, O4, O6, O7, O18) and certain markers of pathogenicity (MRA, Hly, K1, Col) support the concept that E. coli strains have a clonal connection.

Antigens, Bacterial↗
PubMed1985

Epidemiological analysis of Salmonella typhi-murium infections on the basis of laboratory methods. I. Distribution of phage types and biotypes of Salmonella typhi-murium isolated in Hungary in the period 1960 to 1981.

Phage and biochemical types were determined of 34 937 Salmonella typhi-murium cultures including 31 708 human strains, 2732 animal strains and 497 strains isolated from water. Phage type 4, not typable strains (nt) and phage type 2b were predominant among the strains of human and animal origin, and nt, 4 and 2b among the strains isolated from water. The most frequent phage types and the nt strains were subdivided by biotyping and additional phages. The incidence of S. typhi-murium var. copenhagen strains was 12.4%, they belonged mainly to phage types 2b and nt. The number of S. typhi-murium isolates of human origin showed a 2-4 year periodical fluctuation between 1960 and 1981. A connection was found between the incidence of the predominant phage types (4, nt, 2b) and the periodical changes in the total number of isolates. Phage type 4, which predominated among the strains of human and animal origin till 1976, was ousted gradually by nt ones. In the period when the change in predominance was observed the number of epidemics decreased and the number of sporadic cases increased. The change in the frequency of phage types took place at the same time when the frequency of phage types changed among the strains isolated from cattle and meat-products (4----nt). The increased number of sporadic cases after 1976 refers to infections from cattle and not from poultry.

Animals↗
PubMed1985

Epidemiological analysis of Salmonella typhi-murium infections on the basis of laboratory methods. II. Resistance to antibiotics and R-plasmid carrier state in Salmonella typhi-murium isolated in Hungary in the period 1974 to 1981.

Phage and biochemical typing of Salmonella typhi-murium strains performed in the course of the Salmonella Surveillance Programme were completed with examinations on resistance to antibiotics and R-plasmids. A total of 15 600 strains of human, animal and water origin were tested between 1975 and 1981 and most of the monoresistant strains were found among the animal strains (73.6%-94.9%), while double resistance was the most frequent among the human strains (5.5%-25.5%) and multiresistance occurred in the highest ratio (2.8%-25.6%) among the strains of water origin. Tetracycline resistance was the most frequent in all the three materials. The curves representing the incidence of tetracycline (Tc), chloramphenicol (Cm), streptomycin (Sm), kanamycin (Km) resistance were similar to the curve of multiple resistance and differed from the curve showing the incidence of ampicillin (Ap) resistance. Gentamicin resistance was found only among human strains (in 0.3 and 0.7%), strains resistant to nitrofurantoin and co-trimoxazole occurred among strains of human and water origin in low percentages. The most common antibiotic resistance patterns of the multiple resistant strains were Tc, Cm, Sm, Km, Ap, Su; Tc, Sm, Su; Sm, Km, Ap, Su. Multiple resistant strains belonged in the majority to phage type nt (not typable) and 2b. Out of the examined 512 S. typhi-murium strains resistant to antibiotics, the presence of R-plasmid was demonstrated in 408 strains (i.e. 79.7%). The R-plasmids, derived from strains of human, animal and water origin, of phage type nt, biotype 3 (nt/3) isolated in 1979, were characterized according to the resistance determinants, fi-character, incompatibility-group, phage-inhibition and molecular weight. Two kinds of R-plasmids were carried by three human strains (FI and H, FI and alpha). R-plasmids belonging to Inc P and Inc H were carried by one animal strain. Strains isolated from sewage carried R-plasmids of Inc groups H and I alpha. Out of the examined 15 S. typhi-murium strains of phage type 2b, isolated in 1981, the molecular weight for 7 strains was 66 Md and four belonged to Inc I alpha. The R-plasmids derived from 2b/2 strains, isolated in the same county, were identical according to antibiotic resistance determinants, phage inhibition and molecular weight. The molecular weights of R-plasmids derived from 10 strains out of the examined 30 nt strains were also 66 Md and the four examined plasmids belonged also to Inc I alpha.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Escherichia coli Col V plasmids and their role in pathogenicity.

Out of 1474 Escherichia coli strains belonging to 70 serogroups and 247 serologically not identified ones, colicin V producers were found in serogroups O78, O1, O7, O18 and also among the not identified strains. The molecular weight of Col V1 plasmid from the standard strain was 70 Mdal. The Col V plasmids carried by E. coli O78 strains isolated from a hospital outbreak in Hungary had a molecular weight of 78 Mdal and also 78 Mdal was the molecular weight of the Col V plasmid carried by Rivier's strain (designated 23), which had caused meningitis in Switzerland. The molecular weight of Col V plasmids of O1: K1, O21, O161 and serologically not identified E. coli strains isolated from sporadic cases was of 94 to 119 Mdal. In the case of three strains the increase of LD50 values, which means the decrease of virulence, resulted in the loss of colicin V production and the loss of Col V plasmid. It was demonstrated by introduction of a transposon, inactivating colicin V production, into a wild type E. coli strain that the production of colicin was not essential for the increase of virulence controlled by Col V plasmid. In the case of one strain the loss of both R and Col V plasmid resulted in a decrease of virulence. No plasmid other than R and Col V was carried by this strain. The virulence determining gene could be eliminated together with both plasmids, which means that this gene could be attached equally to Col V and R plasmid.

Animals↗
PubMed1981

Klebsiella and Enterobacter strains derived from hospital infections. II. Occurrence and characterization of R-, Lac- and Col- plasmids and their clinical-epidemiological significance.

A total of 269 hospital Klebsiella strains and 103 hospital Enterobacter strains showed 34 and 10 different antibiotic resistance patterns, respectively. Among multiple resistant Klebsiella and Enterobacter strains the Ap Sm Cm Tc resistance pattern was the most frequent (K. aerogenes). Antibiotic resistant strains carried R-plasmids in 27.5%. The presence of R-plasmids was demonstrable in 2.9% of single antibiotic resistant, in 12.8% of double antibiotic resistant, and in 71.4% of multiple antibiotic resistant Klebsiella strains. R-plasmid carriage was most frequent in strains of the species K. pneumoniae and K. atlantae. Transfer frequency of R-plasmids of multiple resistant strains was generally higher into Escherichia coli K12 recipient (10-1 to 10-2) than into K. pneumoniae recipient (10-3 to 10-5). Regarding the individual resistance determinants, transfer frequency of Km-Nm resistance was the highest (65.1%). The lac-plasmid was demonstrable in 18 out of the 77 R-plasmid carrying Klebsiella strains. R- and Lac-plasmids of single and multiple resistant Klebsiella strains could be transferred into E. coli and Klebsiella recipients in mice in vivo. As many as 67% showed fi- and 33% showed fi+ character among the demonstrated 112 R-plasmids. Regarding their incompatibility, the studied five plasmids belonged to groups FI, FII and I alpha. Altogether 14 different groups could be distinguished among R-plasmids on the basis of their phage restriction capability on phage lambda and coliphages T, and another group of R-plasmids showing no restriction at all. Fi+ character was demonstrated in 54.5% of R-plasmids showing phage restriction capability and in 10.9% of R-plasmids showing no phage restriction. Nearly twice as many R-plasmids carrier strains were found among non-typable ones as among those typable by phages. Three R-plasmids showed phage-modification among 51 R-plasmids restrictive for phages. In addition to the phage-type of Klebsiella strains, R-plasmids can also be used as an epidemiologic marker.

Bacteriocin Plasmids↗
PubMed1981

Klebsiella and Enterobacter strains derived from hospital infections. I. Correlation between species, phage type and antibiotic sensitivity.

Four hundred and seventy Klebsiella and 103 Enterobacter strains derived from urogenital infections, upper respiratory tract and wound infections were examined. (i) K. aerogenes was the most common among Klebsiella species, K. ozaenae and K. atlantae occurred frequently, K. pneumoniae, K. rhinoscleromatis, K. edwardsii and K. oxytoca were found rarely. The strains isolated from urine showed the most heterogeneous species distribution. Enterobacter species were in the order of frequency E. cloacae, E. liquefaciens, E. aerogenes. (ii) K. aerogenes strains belonged to 10, K. atlantae strains to 6 phage types; phage type II.A1 was the most frequent phage types. Typability varied between 23.7% and 48.0% with the different Klebsiella species, except K. edwardsii and K. oxytoca strains. None of the strains of these species were typable by phages. Among the Enterobacter species examined, only one E. liquefaciens strain was typable by phages. Strains of genus Enterobacter were lysed by the diagnostic phage C14 in 64%, no lysis was observed in the strains of genus Klebsiella. (iii) Multiple resistance was demonstrated in 36.6% of Klebsiella strains and in 16.5% of Enterobacter strains. The majority of the multiresistant strains was isolated from urine in both genera. Multiresistant strains belonged to the species K. aerogenes, E. cloacae and E. liquefaciens. Strains resistant to ampicillin were divided into 6 groups on the basis of cephaloridine and cephalothin resistance. The rate of multiresistant strains was higher among the Klebsiella and Enterobacter strains not typable by phages than in the typable ones.

Anti-Bacterial Agents↗
PubMed1980

Salmonella typhi R-plasmids in Hungary.

The antibiotic sensitivity of 4095 Salmonella typhi strains isolated in Hungary from January, 1974 to June 1979, was tested. Twelve strains derived from one patient and seven chronic carriers were resistant to antibiotics due to R-plasmids. One of the S. typhi strains carried two R-plasmids and the change in the phage type of this strain was caused by one of the plasmids. R-plasmid of the same restrictive property was found in an Escherichia coli strain isolated from the faeces of the corresponding carrier. All of the R-plasmids examined were fi-, E. coli and Shigella flexneri phages were restricted by four R-plasmids, S. typhi phages were restricted by one. R-plasmids belonged to incompatibility groups I1, I2, W and H.

Anti-Bacterial Agents↗