Postoperative spondylodiscitis due to Kytococcus schroeteri in a diabetic woman

Kytococcus schroeteri, a Gram-positive coccus, is usually regarded as part of the human skin flora. It has been described in prosthetic valve endocarditis but never as being involved in osteoarticular infections. We report here the first case of a spondylodiscitis due to K. schroeteri identified by 16S rRNA gene sequencing.

Selection during cefepime treatment of a new cephalosporinase variant with extended-spectrum resistance to cefepime in an Enterobacter aerogenes clinical isolate

Enterobacter aerogenes resistant to cefepime (MIC, 32 microg/ml) was isolated from a patient treated with cefepime for an infection caused by a strain of E. aerogenes overproducing its AmpC beta-lactamase (MIC of cefepime, 0.5 microg/ml). The AmpC beta-lactamase of the resistant strain had an L-293-P amino acid substitution and a high k(cat)/K(m) ratio for cefepime. Both of these modifications were necessary for resistance to cefepime.

Extension of resistance to cefepime and cefpirome associated to a six amino acid deletion in the H-10 helix of the cephalosporinase of an Enterobacter cloacae clinical isolate

Enterobacter cloacae CHE, a clinical strain with overproduced cephalosporinase was found to be highly resistant to the new cephalosporins, cefepime and cefpirome (MICs> or =128 microg ml(-1)). The strain was isolated from a child previously treated with cefepime. The catalytic efficiency of the purified enzyme with the third-generation cephalosporins, cefepime and cefpirome, was 10 times higher than that with the E. cloacae P99 enzyme. This was mostly due to a decrease in K(m) for these beta-lactams. The clinical isolate produced large amounts of the cephalosporinase because introduction of the ampD gene decreased ampC expression and partially restored the wild-type phenotype. Indeed, MICs of cefepime and cefpirome remained 10 times higher than those for a stable derepressed clinical isolate (OUDhyp) transformed with an ampD gene. Sequencing of the ampC gene showed that 18 nucleotides had been deleted, corresponding to the six amino acids SKVALA (residues 289--294). According to the crystal structure of P99 beta-lactamase, this deletion was located in the H-10 helix. The ampR-ampC genes from the clinical isolates CHE and OUDhyp were cloned and expressed in Escherichia coli JM101. The MICs of cefpirome and cefepime of E. coli harboring ampC and ampR genes from CHE were 100--200 times higher than those of E. coli harboring ampC and ampR genes from OUDhyp. This suggests that the deletion, confirmed by sequencing of the ampC gene, is involved in resistance to cefepime and cefpirome. However, the high level of resistance to cefepime and cefpirome observed in the E. cloacae clinical isolate was due to a combination of hyperproduction of the AmpC beta-lactamase and structural modification of the enzyme. This is the first example of an AmpC variant conferring resistance to cefepime and cefpirome, isolated as a clinical strain.

Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome

OBJECTIVE

Small intestinal bacterial overgrowth syndrome (SIBOS) is characterized by an abnormally high bacterial population level in the upper gut, exceeding 10(5) organisms/ml (5 log colony-forming unit (CFU)/ml). To understand its origin and select an appropriate antibiotic treatment, we have analyzed the bacterial populations contaminating the upper gut in SIBOS patients.

METHODS

Jejunal samples of 63 consecutive patients with diarrhea or malabsorption and conditions predisposing to SIBOS were cultured and antibiotic sensitivities determined.

RESULTS

Concentrations of total, microaerophilic, and anaerobic bacteria were confirmed in 55 patients with SIBOS (mean +/- SE) 7.6 +/- 0.8, 7.4 +/- 0.9, and 6.1 +/- 0.7 log CFU/ml, respectively. Mean number of bacterial genera was 4.6 +/- 0.8. The main bacteria recovered were (mean +/- SE log CFU/ml) Streptococcus (71%; 6.4 +/- 0.8), Escherichia coli (69%; 7.2 +/- 0.9), Staphylococcus (25%; 6.2 +/- 0.6), Micrococcus (22%; 6.0 +/- 0.7), Klebsiella (20%; 7.1 +/- 0.8), Proteus (11%; 6.1 +/- 0.8) for microaerophilic bacteria, and Lactobacillus (75%; 6.1 +/- 1.1), Bacteroides (29%; 6.9 +/- 1.3), Clostridium (25%; 5.5 +/- 1.0), Veillonella (25%; 5.3 +/- 0.7), Fusobacterium (13%; 4.8 +/- 0.5), and Peptostreptococcus (13%; 6.1 +/- 0.7) for anaerobic bacteria. Amoxicillin-clavulanic acid and cefoxitin were efficient on >90% of strains.

CONCLUSIONS

Contaminating flora isolated in SIBOS include commonly identified oropharyngeal and colonic flora, but these occur in SIBOS at different levels from those usually found in their original location. These data may hopefully serve as a starting point to further therapeutic controlled studies.

Qualitative immunoglobulin abnormalities in HIV-positive patients: long-term follow-up

We studied the immunoglobulins of a cohort of 212 HIV-positive patients followed-up for 13 years. The qualitative study of immunoglobulins by immunoelectrophoresis and immunofixation distinguished three groups of patients: those with monoclonal immunoglobulins, those with minor abnormalities of immunoglobulins and those with polyclonal immunoglobulins. We characterized these groups according to age, sex, immunoglobulin isotypes, and survival curves. The results show that this population of immunoglobulinopathies has distinctive characteristics. In particular, the presence of immunoglobulin abnormalities has no significant prognostic value.

Failure of ganciclovir treatment associated with selection of a ganciclovir-resistant cytomegalovirus strain in a lung transplant recipient

We report the case of a lung transplant recipient with progressive cytomegalovirus (CMV) disease due to a resistant CMV strain emerging under ganciclovir (GCV) therapy. A discriminative polymerase chain reaction (PCR) assay, designed to detect the resistance-related V460 mutation within the viral enzyme UL97, revealed the presence of a mutated strain in a heterogeneous isolate 51 days after transplantation. The conventional antiviral susceptibility assay had failed to demonstrate resistance to GCV. Under prolonged GCV therapy, the mutated strain dominated the wild-type strain, as shown by the PCR assay. This domination led to laboratory resistance, associated with recurrent fever and progressively severe retinitis. As this discriminative PCR assay was shown to be effective in detecting mutated strains that constitute a minority in the virus load, it should allow better management of patients with CMV disease.

[Resistance of cytomegalovirus to ganciclovir: rapid detection of the mutations 460 of the UL97 phosphotransferase]

The substitution of methionine by either isoleucine or valine at residue 460 in the UL97 phosphotransferase has been shown to be responsible for resistance to ganciclovir (GCV) in 30% of resistant cytomegalovirus (CMV) isolates [4]. These substitutions require one nucleotide change in the gene (G- > T 1 380 and A- > G 1378 respectively). The aim of this study was to develop a discriminative PCR assay for rapid detection of these DNA changes. A PCR assay was duplicated in parallel for each mutation; to detect G- > T 1380 each reaction mixture contained primer VSUL14 and either primer LNW to distinguish wild type residues or LNM to distinguish mutant residues, and for A- > G 1378 primers were VSUL8 and either MCMW to detect wild type sequences or MCMM to detect mutated residues. For optimal discrimination, primers MCMW and MCMM were designed with a mismatch at position 3'-1. The reference strains AD169, Davis and Towne, a laboratory GCV-resistant mutant RCL1.7, and 33 CMV isolates (10 resistant, 2 indetermined and 21 sensitive) were tested by PCR. AD169, Davis and Towne, and 30 isolates were amplified only with non modified primers, and the absence of 460 mutations was confirmed by sequencing. Two isolates P1 and P2, from a transplanted patient were amplified with both MCMM and MCMW: sequencing analysis shown the presence of a mixture of strain, one of them harbouring A- > G 1378 mutation. One resistant strain was amplified neither with MCMM nor with MCMW: a C- > T silent mutation at nt 1368 was present. As sequencing analysis confirmed PCR results, discriminative PCR enables isolates to be rapidly assessed for the presence or absence of 460 mutations. Moreover, it can distinguish Met to Val from Met to Ile mutations, and allows the analysis of mixtures of sensitive ad resistant strains.

Value of a new rapid non-radioactive sequencing method for analysis of the cytomegalovirus UL97 gene in ganciclovir-resistant strains

Various DNA changes located within a restricted region of the UL97 open reading frame were shown to be associated with the resistance of cytomegalovirus strains to ganciclovir (GCV). In order to analyse this UL97 region in sensitive and GCV-resistant strains, a non-radioactive sequencing assay (Promega, Madison, WI, USA) which combines the dideoxy visualisation by silver-staining of the gel was used. Using this assay, polymerase chain reaction products from results were obtained within 1 day. Point mutations modifying the amino acid sequence of the putative UL97 catalytic site were detected in three isolates. These led to an alanine to valine substitution in residue 594 in one strain with reduced GCV sensitivity, and to a cysteine to glycine substitution in residue 592 in two GCV-resistant isolates. These mutations were different from the DNA changes previously mapped in GCV-resistant laboratory or field strains. No amino acid substitution in the UL97 catalytic site was found in GCV-sensitive isolates. Transfer marker experiments are in progress in order to test the significance of these DNA changes for GCV resistance. This rapid non-radioactive sequencing protocol could be a useful tool for analysing the UL97 region encoding the putative UL97 catalytic site of clinical isolates.

Prevalence of HIV infections among patients attending a Parisian anonymous testing center between 1988 and 1993

The prevalence of HIV infection was assessed among 15,611 consecutive patients attending a Parisian anonymous testing center from April 1988 to June 1993. Sera (17,910) were tested for the presence of anti-HIV antibodies using two different enzyme-linked immunosorbent assays. Seropositivity was verified by Western blotting. The sera were also assayed for HIV antigenemia detection in 2,493 cases. Six hundred and seventy-seven patients were found to be anti-HIV antibody positive: among them 666 were infected by HIV-1 and only 11 by HIV-2. Antigenemia was detected in 108 samples (4.3%). In all cases but 5, antigenemia was associated with the presence of specific antibodies. Risk factors for HIV infection could be determined for 5,735 patients. The HIV prevalence rates were 5.2% in 1988-89, 4.9% in 1990, 3.4% in 1991, 2.8% in 1992 and 1.8% for the 6 first months of 1993 (p < 0.01). Only one patient was coinfected with HTLV-1. This study shows a trend of decreasing seropositivity rates among the patients attending the anonymous testing center since 1990. By contrast, the percentage of seropositive patients with antigenemia was stable between 1988 and 1993.

Rapid detection of cytomegalovirus strains resistant to ganciclovir through mutations within the gene UL97

The human cytomegalovirus (HCMV) gene UL97 product was shown to play an important role in phosphorylation of ganciclovir (GCV) in HCMV-infected cells. The deletion of the 4 amino-acid sequence AACR confers resistance to a laboratory mutant. The aim of this study was to develop a rapid and simple method to detect mutations within the 12 base pair (bp) fragment encoding AACR, from isolates and clinical specimens (urine, bronchoalveolar lavage, cerebral spinal fluid samples). A target region encompassing this 12bp sequence was amplified by a single-step PCR assay from HCMV isolates and reference strains, and a two-step procedure from clinical specimens. Reaction products were submitted to restriction enzyme analysis and dot-blot hybridization assay. Two biotinylated probes were used: one probe (DL) overlapping the 12bp region; and a control probe with similar length and GC content. Hybridization was performed under conditions allowing the detection of one bp deletion (HCMV strain susceptibility to GCV was determined by a rapid late antigen synthesis reduction assay.) The control probe hybridized to the UL97 sequence amplified from all 23 tested isolates and the reference strains. The DL probe gave a positive signal with GCV-susceptible strains; no signal was obtained for five out of seven resistant isolates, and for a laboratory mutant derived from the strain AD169. Restriction analysis of amplification products showed different patterns suggesting this region can be involved in various DNA changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Biotypes, serotypes, and susceptibility to antibiotics of 60 Haemophilus influenzae strains from genitourinary tracts

Sixty strains of Haemophilus influenzae were isolated from the genitourinary tracts of adults: 19 from cervicovaginal secretions, one from a woman with bartholinitis, 37 from urethral exudates, and three from urine. Non-capsulated strains were recovered predominantly, and biotype III accounted for 28 isolates and biotype IV for 25. Many of the H influenzae strains were found to be resistant to one or more of the antibiotics commonly used against sexually transmitted diseases. Resistance to tetracycline was prevalent and was found in 17 of the strains. Ten strains were ampicillin resistant and beta lactamase producing. Kanamycin resistance was less common (two strains). Trospectomycin (U-63366), a new spectinomycin analogue, was eight to 16 times more active than spectinomycin. All the quinolones tested were very active against all strains and may provide an effective alternative for the treatment of resistant H influenzae in genitourinary infections.

In vitro susceptibility of 96 Capnocytophaga strains, including a beta-lactamase producer, to new beta-lactam antibiotics and six quinolones

The in vitro activities of new beta-lactam antibiotics and new quinolones were studied against 96 Capnocytophaga strains, including a beta-lactamase-producing strain which was resistant to ampicillin, amoxicillin, carbenicillin, cephalothin, and cefamandole. All strains were susceptible to the combination of amoxicillin and clavulanic acid, ureidopenicillins, cefoxitin, broad-spectrum cephalosporins, and imipenem. Cephalothin and cefamandole did not show good activity against most strains. All Capnocytophaga spp. were uniformly susceptible to the five new quinolones tested.

[In vitro activities of 9 aminosides against of 250 strains of Neisseria gonorrhoeae]

We compared the in vitro activities of 9 aminoglycosides including trospectomycin sulfate against 250 selected strains of Neisseria gonorrhoeae according to their penicillin resistance (penicillinase production), streptomycin resistance, spectinomycin resistance. Trospectomycin sulfate inhibited all spectinomycin-sensible strain at a concentration of 4 mg/l but the spectinomycin-resistant strain needed 32 mg/l for its inhibition. Among the other aminoglycosides tested netilmicin had the most in vitro effectiveness. Its minimal inhibitory concentrations were comparable to that of trospectomycin sulfate: furthermore this compound demonstrated in vitro activity against the spectino-resistant strain.

In vitro activities of U-63366, a spectinomycin analog; roxithromycin (RU 28965), a new macrolide antibiotic; and five quinolone derivatives against Haemophilus ducreyi

The in vitro activities of the new spectinomycin analog U-63366, the new macrolide roxithromycin (RU 28965), and five new quinolone derivatives (pefloxacin, rosoxacin, norfloxacin, ofloxacin, and ciprofloxacin) were studied against 23 multiresistant strains of Haemophilus ducreyi (beta-lactamase producers) isolated in Paris and were compared with the activities of tetracycline, minocycline, chloramphenicol, streptomycin, kanamycin, gentamicin, spectinomycin, erythromycin, and nalidixic acid. All strains were uniformly susceptible to the seven new antibiotics tested. Ciprofloxacin had the greatest inhibitory effect in vitro (the MIC for 90% of the strains tested [MIC90] was 0.016 microgram/ml), and U-63366 was the most active aminoglycoside-aminocyclitol antibiotic (MIC90, 0.25 microgram/ml).

[Actinomyces israelii. Methods of isolation and identification. Apropos of 10 cases]

Actinomyces israelii was isolated from cervico-facial subacute or chronic infections (9 cases), and abdominal wall abscess (1 case). Two conditions were necessary for successful isolation of A. israelii: properly collected clinical specimen (pus aspirated from abscess or biopsy) and prolongated incubation of anaerobic cultures (at minimum 5 days). Two commercially available micro-method multitest systems (Api 20 anaerobes, Api Zym test) were compared with standard biochemical procedures. The three methods were evaluated as to the reproducibility and help in identifying anaerobic non spore-forming Gram-positive bacilli in a routine clinical laboratory.

In-vitro susceptibility of thirty strains of Haemophilus ducreyi to several antibiotics including six cephalosporins

We have studied the in-vitro susceptibility of 30 strains of Haemophilus ducreyi to 22 antibacterial agents. Twenty-seven strains produced a beta-lactamase that had an isoelectric point similar to the isoelectric point of the TEM 1 type beta-lactamase produced by pSF 2124. Except for cefamandole, the 30 strains had similar susceptibilities to the different cephalosporins, cefotaxime being the most active compound. Twenty-two isolates were resistant to tetracycline and doxycycline; minimal inhibitory concentration (MIC) of minocycline was 4 mg/l for all the strains. One isolate was resistant to chloramphenicol (MIC = 16 mg/l). All strains were relatively resistant to colistin and nalidixic acid, and susceptible to streptomycin, kanamycin, gentamicin, erythromycin, rifampicin and vancomycin.

The enzymatic profile of Haemophilus ducreyi

The enzymatic activities of two reference strains of Haemophilus ducreyi and thirty clinical isolates were investigated by conventional biochemical tests and the API-ZYM test kit system which included 97 synthetic substrates. No strains converted delta-aminolevulinic acid to porphyrins, but they all reduced nitrates to nitrites. All strains possessed aminopeptidase activity against beta-naphthylamide derivatives of L-alanine, L-arginine, L-glutamine, glycine, L-leucine, L-lysine and L-serine. No trypsinor chymotrypsin-like activities were detected. All strains had phosphatase activity with broad pH range, and phosphoamidase activity. No glycosidase was detected by the substrates tested.

Detection of chloramphenicol acetyltransferase (CAT) activity in a strain of Haemophilus ducreyi

The minimal inhibitory concentration (MIC) of chloramphenicol for a clinical isolate of Haemophilus ducreyi, strain CEB-10, was 16 micrograms/ml. This strain was also resistant to tetracycline (MIC = 64 micrograms/ml) and ampicillin. The presence of a chloramphenicol acetyltransferase (CAT) activity was demonstrated.