European Journal of Clinical Microbiology Infectious Diseases

Jordens, J.; Slack, M.

doi: 10.1007/BF01691374pmid: 8654443

Haemophilus influenzae has long been recognised as a major cause of serious infection and mortality in children less than 5 years old. Prior to the introduction of Haemophilus influenzae type b (Hib) immunisation, the incidence of a child suffering an invasive Haemophilus infection was 20–50/100,000 in industrialised countries and up to ten times higher in developing regions. The introduction of a Hib vaccine programme results in a rapid and dramatic decline in the incidence of Hib infection in the susceptible childhood population. For example, within two years of the introduction of routine Hib vaccination of infants in the UK, the risk of serious Hib infection had fallen from 1∶600 to 1∶30,000 by 5 years of age. Many other European countries have introduced, or are in the process of introducing, a routine Hib immunisation programme. Because the epidemiology of Haemophilus influenzae infection is changing so dramatically, it is opportune to review Haemophilus influenzae as it was perceived in the pre-vaccine era (the past) and during vaccine implementation (the present), and how its role may change in the post-vaccination era (the future). This review will summarise the historical landmarks that have led to our present-day understanding of Haemophilus influenzae pathogenicity, the concerns about antibiotic resistance, the features of the host immune response to Haemophilus influenzae , and the introduction of the Hib vaccine. Furthermore, the possible importance of this organism in the future will be discussed.

Sánchez-Quijano, A.; Andreu, J.; Gavilán, F.; Luque, F.; Abad, M.; Soto, B.; Muñoz, J.; Aznar, J.; Leal, M.; Lissen, E.

doi: 10.1007/BF01691375pmid: 8654444

Bernal, M.; Leyva, A.; Garcia, F.; Galan, I.; Piedrola, G.; Heyermann, H.; Maroto, M.

doi: 10.1007/BF01691376pmid: 8654445

In order to determine the seroprevalence of hepatitis E virus, 1,993 sera (453 from healthy pregnant women, 491 from Moroccan subjects, 492 from blood donors, 321 from children, and 236 from intravenous drug users) were studied. IgG was measured by enzyme immunoassay (EIA), and positive results were confirmed by Western blot. The EIA detected antibodies in 3.96 % of the subjects (5.6 % of the Moroccans and drug users and 1.8 % of the children). Fifty-four percent of these results were confirmed by Western blot, 11.4 % were found to be negative, and 34.2 % indeterminate. The overall prevalence after confirmation by Western blot decreased to 2.15 %. When studying the Western blot pattern of the positive samples, 95 % showed antibodies to SG-3, 65 % to 8–5, and only 9.3 % to CKS fusion protein. In the indeterminate Western blots, the results for these proteins were 96.3 %, 62.9 %, and 37 %, respectively. When the epidemiological data were analysed, no statistically significant differences between women and men or between different age groups were found.

Plessis, P.; Lamy, T.; Donnio, P.; Autuly, F.; Grulois, I.; Prisé, P.; Avril, J.

doi: 10.1007/BF01691377pmid: 8654446

Vancomycin-resistant enterococci have been isolated with increasing frequency since 1988. Thus far, most of these resistant enterococci have belonged to the Enterococcus faecium species, and epidemiological studies have shown a wide diversity among inter-hospital and intrahospital isolates. This report presents an epidemiologic investigation of 25 vancomycin-resistant Enterococcus strains — 24 Enterococcus faecium and one Enterococcus gallinarum — isolated from the stools or blood of adult patients receiving intravenous vancomycin prophylaxis during neutropenia and hospitalized in a single hematologic unit. Macrorestriction patterns of total DNA and of ribosomal DNA regions were used to analyze the strains. Strains produced different total DNA restriction fragment length polymorphism patterns after Smal digestion. Ribotyping was less discriminative than pulsed-field gel electrophoresis. The results confirmed the genetic unrelatedness of the strains. Prolonged vancomycin administration, commonly used in hematologic units, could be involved in the selection of endogenous resistant enterococcal strains.

Colom, K.; Fdz-Aranguiz, A.; Suinaga, E.; Cisterna, R.

doi: 10.1007/BF01691378pmid: 8654447

The contribution of induction and stable derepression of chromosomal class I β-lactamases to β-lactam antibiotic resistance was studied in clinical isolates of Pseudomonas aeruginosa collected from patients treated with β-lactam antibiotics. Multiple isolates from the same patient were characterized by O-serotyping as a primary screen, combined with pyocin typing. Sonicated extracts of cells were assayed for chromosomal and plasmid-mediated β-lactamases by isoelectric focusing and cloxacillin inhibition studies. The specific β-lactamase activity, basal and induced, with cefoxitin was determined to differentiate strains with inducible or derepressed production of the enzyme. Beta-lactamase induction was performed in each strain against the β-lactam agents used in the therapy of each patient. The observations showed that induction against older penicillins such as penicillin, amoxicillin, and amoxicillin/clavulanate resulted in a moderate to strong increase in β-lactamase activity, whereas the results obtained with first-generation cephalosporins varied with the β-lactam agent tested. Third-generation cephalosporins were weak inducers of β-lactamases, and their use as therapy preceded the appearance of strains that produce chromosomal group I β-lactamases constitutively. These strains showed a remarkable reduction in sensitivity to ureidopenicillins, carboxipenicillins, third-generation cephalosporins, and monobactams, but not to carbapenems.

Vanjak, D.; Muller-Serieys, C.; Picard, B.; Bergogne-Berezin, E.; Lambert-Zechovsky, N.

doi: 10.1007/BF01691379pmid: 8654448

The efficacy of the clinically available β-lactam/β-lactamase inhibitor combinations (amoxicillin/clavulanic acid (CA), ticarcillin/CA, amoxicillin/sulbactam, and piperacillin/ tazobactam) was evaluated on 300 amoxicillin-resistant Escherichia coli isolates having the main patterns of β-lactam resistance. The patterns, which reflect the production of various β-lactamase enzymes, were analyzed by a principal component analysis of susceptibility to 11 β-lactam antibiotics or β-lactam/β-lactamase inhibitor combinations. Sixty-two percent of strains were not very susceptible to penicillins, cephalothin, or any β-lactam/β-lactamase inhibitor combinations except for piperacillin/tazobactam; these strains may represent high-level broad-spectrum β-lactamase (so-called penicillinase) production phenotype or inhibitor-resistant TEM-like enzyme production phenotype. Of the strains, 14.7 % were resistant to amoxicillin and ticarcillin compatible with low-level broad-spectrum β-lactamase production phenotype; 5.7 % were cefoxitin resistant and were postulated to present a high-level cephalosporinase production phenotype; and 2.6 % were resistant to cephalothin only, attributable to a low-level cephalosporinase production phenotype. Three percent of strains were intermediate or resistant to cefotaxime and may produce an extended-spectrum β-lactamase, and the remaining strains (12 %), resistant to all tested antibiotics except for cefotaxime and piperacillin/tazobactam, were hypothesized to produce both broad-spectrum β-lactamase plus cephalosporinase. The minimal inhibitory concentration (MIC) for these phenotype patterns indicated that combinations of CA plus amoxicillin or ticarcillin, or sulbactam plus amoxicillin, restored the activity of penicillins against phenotype 1 strains, whereas these combinations remained inactive against the other phenotype strains. Piperacillin plus tazobactam showed the best in vitro effect against the strains of all resistance phenotypes.

Dib, C.; Trias, J.; Jarlier, V.

doi: 10.1007/BF01691380pmid: 8654449

Eighty-nine clinical isolates resistant (n=61) or susceptible (n=28) to imipenem and exhibiting the main patterns of susceptibility to other β-lactam agents (wild type pattern, penicillinase pattern, constitutive cephalosporinase pattern) were studied in order to investigate (i) the mechanism of resistance involved and (ii) whether resistance to carbapenems affects the level of resistance to other β-lactam agents and, conversely, if resistance to other β-lactam agents affects the level of resistance to carbapenems. For this purpose, the presence of OprD protein in the cell wall was detected by Western blot and β-lactamase activity by spectrophotometric assay and isoelectric focusing. OprD expression was not detectable in the imipenem-resistant (MIC≥16 μg/ml) strains. It was decreased in half the strains for which MICs of imipenem were 2 to 8 μg/ml and was close to a normal level in the most susceptible strains (MIC ≤1 μg/ml), thus demonstrating a direct correlation between the level of susceptibility to imipenem and the level of OprD expression. No imipenemase activity was detected in imipenem-resistant strains. Synergy between imipenem or meropenem and BRL42715 was observed for all of the strains, demonstrating the role of cephalosporinase in carbapenem resistance. Within each pattern of susceptibility, the mean MICs of β-lactam agents other than carbapenems were similar, whether the strains were susceptible or resistant to imipenem. Conversely, the mean MICs of imipenem or meropenem for either the imipenem-resistant or the imipenem-susceptible strains were similar, regardless of the susceptibility of these strains to the other β-lactam agents. Thus, when several mechanisms of resistance to β-lactam agents are present in the same strain of Pseudomonas aeruginosa , there is no additive effect between these mechanisms.

Talon, D.; Bailly, P.; Delmée, M.; Thouverez, M.; Mulin, B.; Iehl-Robert, M.; Cailleaux, V.; Michel-Briand, Y.

doi: 10.1007/BF01691381pmid: 8654450

A six-month outbreak of Clostridium difficile infection among elderly residents of a middle-term-care facility was investigated. Pulsed-field gel electrophoresis was used to genotype 22 outbreak strains and 30 epidemiologically unrelated strains. A prospective case-control study was conducted to identify risk factors for epidemic Clostridium difficile -associated diarrhea. All epidemiologically unrelated Clostridium difficile strains of the same serogroup could be differentiated by their DNA patterns with two restriction enzymes ( Smal and Kspl ). Among clustered strains, two epidemic serogroups (C and K) were identified. Two different DNA patterns were identified among serogroup C strains and three among serogroup K strains. Multivariate analysis showed that the risk of Clostridium difficile infection increased with antimicrobial chemotherapy (β-lactam agents and pristinamycin) and the presence of a feeding tube. This study confirms the high discriminative power of restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis to describe Clostridium difficile epidemiology. The typing results confirm that infection was principally exogenous in this outbreak. Furthermore, they indicate the need to improve all measures limiting transmission of infection.

Strle, F.; Cheng, Y.; Nelson, J.; Picken, M.; Bouseman, J.; Picken, R.

doi: 10.1007/BF01691382pmid: 8654451

In spring 1993, Ixodes ricinus ticks were collected from six regions of Slovenia to determine their overall rate of infection with Borrelia burgdorferi sensu lato and to assess the frequency of individual species in these tick populations. Ticks were dissected and midgut tissue inoculated into modified Barbour-Stoenner-Kelly (BSK II) medium. Borrelia isolates were differentiated into separate species using species-specific polymerase chain reaction (PCR) primers and by large restriction fragment pattern (LRFP) analysis. Infected ticks were found in all six regions surveyed. Spirochaetes were isolated from 69 of 363 ticks (19 %): the isolation rate from adult female ticks was 35 % (23/66 ticks cultured), from adult male ticks 22 % (20/91), and from nymphal ticks 13 % (26/206). Determination of the species of 60 isolates revealed that 32 were Borrelia afzelii (53 %), 20 were Borrelia garinii (33 %), and 8 were Borrelia burgdorferi sensu stricto (13 %). In the Ljubljana region Borrelia afzelii and Borrelia garinii predominated (43 % and 40 %, respectively), whereas Borrelia burgdorferi sensu stricto constituted only 17 % of isolates. In three other regions of the country Borrelia afzeliiwas isolated exclusively, although the number of isolates investigated was small. This study demonstrates the presence of all three European species of Borrelia burgdorferi sensu lato within the Slovenian tick population and also within a geographic area of less than 100 m 2 .

Kragsbjerg, P.; Norén, T.; Söderquist, B.

doi: 10.1007/BF01691383pmid: 8654436

Three cases of deep soft-tissue infections caused by Streptococcus pneumoniae are presented. All patients were previously healthy adults. The first case was a man with a protracted illness in whom pelvic and inguinal abscesses developed at the site of a scar from a traumatic injury several years earlier. The second patient, a woman, had mastitis with systemic symptoms. The third patient was a woman who developed a gluteal abscess after an intra-muscular injection of a contraceptive. Cellulitis and deep soft-tissue infections caused by Streptococcus pneumoniae are uncommon, but may occur even in immunocompetent adults.