Epidemics of aseptic meningitis due to enteroviruses following national immunization days in Bahrain

We report two successive epidemics of aseptic meningitis due to enteroviruses (EV) observed after national immunization days against polio. Meningitis due to echovirus 30 occurred from July 1995 to the end of January 1996, mostly among children aged 0-12 years (95.1% of cases), and meningitis due to echovirus 4 occurred from May 1996 to the end of September 1996 in the same age group. There were 286 and 169 cases, respectively. Specimens from several representative cases were sent to the WHO Collaborating Center for Virus Reference and Research Laboratory for serological testing and virus detection, including polymerase chain reaction (PCR) studies. Using those tests, evidence of echovirus 30 infection was found in 44% of the children who were sampled during the first epidemic and 45.5% during the second. During echovirus 30 and echovirus 4 epidemics, a similar decline in the age-specific attack rate from 19.1/10,000 and 10.1/10,000 population aged 12 years to 2.4/10,000 and 3.6/10,000 population aged 13 years was observed, respectively.

Suitability of repetitive-DNA-sequence-based PCR fingerprinting for characterizing epidemic isolates of Salmonella enterica serovar Saintpaul

Three molecular typing methods, repetitive-sequence-based PCR (rep-PCR) fingerprinting, plasmid profiling, and arbitrarily primed PCR fingerprinting, were used to characterize isolates of Salmonella enterica serovar Saintpaul. Most of the isolates were obtained from epidemic human cases of food-borne salmonellosis, together with some from the food material suspected to be the source of infection, and a few were obtained from other cases apparently not related to the epidemic. All three methods adequately discriminated the epidemic strain from other strains of the serovar. In addition several isolates from human cases which are not identical to the epidemic strain were found. These isolates therefore must have been responsible for some sporadic infections, which were only temporally related to the epidemic. These strains showed a high degree of similarity to a strain isolated from a turkey. rep-PCR fingerprinting with REP-Dt primers and primer ERIC1R, applicable even to crude cell lysates, offers an attractive choice as a primary method for the discrimination of various Salmonella serotypes as well as isolates within serotype Saintpaul.

Evaluation of a commercially available reverse transcription-PCR assay for diagnosis of enteroviral infection in archival and prospectively collected cerebrospinal fluid specimens

A commercially available reverse transcription (RT)-PCR method (AMPLICOR EV; Roche Diagnostic Systems, Inc., Branchburg, N.J.) was evaluated for detection of enteroviruses in cerebrospinal fluid from patients with neurological disease. This assay was compared with virus isolation in cell culture and an in-house RT-PCR method designed with a nonoverlapping region of the enteroviral genome. A panel of 200 cerebrospinal fluid specimens prospectively collected from patients with a wide variety of neurological symptoms, including 50 patients involved in three different outbreaks of acute aseptic meningitis, was assayed. A second panel of 97 archived cerebrospinal fluid specimens, stored for 2 to 5 years, from patients with aseptic meningitis associated with several enterovirus outbreaks was also studied. From the first panel, enteroviruses were detected in 13 of 50 specimens by cell culture (26%), in 43 of 50 specimens by AMPLICOR EV (86%), and in 46 of 50 specimens by the in-house assay (92%) from patients with aseptic meningitis associated with outbreak and 1 of 29, 3 of 29, and 4 of 29 specimens, respectively, from sporadic cases of aseptic meningitis. The remaining 121 cerebrospinal fluid specimens from patients with other neurological syndromes were negative by all tests. From the second panel, enteroviral RNA was detected by the AMPLICOR test (31 of 97 specimens, 32%) and the in-house assay (39 of 97 specimens, 40%). According to our results, patients with aseptic meningitis should be analyzed for enteroviral infection in cerebrospinal fluid by RT-PCR methods, and the AMPLICOR EV test is a suitable tool for performing such studies. Archival cerebrospinal fluid specimens are less suitable for evaluation of the performance of RT-PCR methods designed for enterovirus detection.

Role of the preaxillary flora in pacemaker infections: a prospective study

BACKGROUND

Infection remains a severe complication after pacemaker implantation. The purpose of our prospective study was to evaluate the role of the local bacteriologic flora in its occurrence.

METHODS AND RESULTS

Specimens were collected at the site of implantation for culture from the skin and the pocket before and after insertion in a consecutive series of patients who underwent elective permanent pacemaker implantation. Microorganisms isolated both at the time of insertion and of any potentially infective complication were compared by using conventional speciation and ribotyping. There were 103 patients (67 men and 36 women) whose age ranged from 16 to 93 years (mean+/-SD, 67+/-15). At the time of pacemaker implantation, a total of 267 isolates were identified. The majority (85%) were staphylococci. During a mean follow-up of 16.5 months (range, 1 to 24), infection occurred in four patients (3.9%). In two of them, an isolate of Staphylococcus schleiferi was recognized by molecular method as identical to the one previously found in the pacemaker pocket. In one patient, Staphylococcus aureus, an organism that was absent at the time of pacemaker insertion, was isolated. In another patient, a Staphylococcus epidermidis was identified both at the time of pacemaker insertion and when erosion occurred; however, their antibiotic resistance profiles were different.

CONCLUSIONS

This study strongly supports the hypothesis that pacemaker-related infections are mainly due to local contamination during implantation. S schleiferi appears to play an underestimated role in infectious colonization of implanted biomaterials and should be regarded as an important opportunistic pathogen.

Genotypic characterization of seven strains of Mycoplasma fermentans isolated from synovial fluids of patients with arthritis

We performed a genotypic characterization of seven strains of Mycoplasma fermentans which have been isolated from the synovial fluid of patients with rheumatoid arthritis (n = 2), spondyloarthropathy (n = 1), and unclassified arthritis (n = 4). We compared them to three reference strains (strains PG18 and K7 and incognitus strain) and to a clinical isolate from the urethra of a patient with nongonococcal urethritis. The characterization methods included electrophoresis of native DNA, arbitrarily primed PCR, and restriction fragment length polymorphism analysis following conventional and pulsed-field gel electrophoresis. Southern blot analysis with a probe internal to an insertion sequence was performed with the restriction products produced by the last two techniques. No extrachromosomal DNA sequences were detected. The M. fermentans strains identified by these methods did not present a unique profile, but they could be separated into two main categories: four articular isolates were genetically related to PG18 and the three other isolates, the urethral isolate, and the incognitus strain were related to K7. We also looked for the presence of the bacteriophage MAV1 (associated with the arthritogenic property of Mycoplasma arthritidis in rodents) in the M. fermentans strains. MAV1 DNA was not detected in either the clinical isolates or the reference strains of M. fermentans.

Clonal identification of Aeromonas hydrophila strains using randomly amplified polymorphic DNA analysis

The suitability of arbitrary primer polymerase chain reaction (RAPD) as a typing technique was evaluated by comparing it with pulsed-field gel electrophoresis (PFGE) to characterize Aeromonas hydrophila strains isolated from a cluster of hospital-acquired infections. Five isolates from patients and 10 isolates from the water supply were compared to 10 epidemiologically unrelated strains isolated from patients and rivers. Two methods were used to prepare DNA and two primers (AP3 and AP5) were selected. The discriminatory power was better with the extractive DNA preparation than the boiling method. The discrimination of closely related from less related strains by PCR using AP3 was consistent with that by PFGE: water supply of Cholet hospital contaminated with Aeromonas species was not the source of the cluster of hospital infections and only two patients were infected with clonally-related strains. RAPD using primer AP3 was simpler, cheaper, and quicker to perform than pulsed-field gel electrophoresis and is well suited for the epidemiological study of A. hydrophila isolates.

Ureaplasma urealyticum respiratory tract colonization is associated with an increase in interleukin 1-beta and tumor necrosis factor alpha relative to interleukin 6 in tracheal aspirates of preterm infants

OBJECTIVE

To determine whether Ureaplasma urealyticum respiratory tract colonization in very low birth weight infants during the first week of life is associated with changes in tracheal aspirate concentrations of the cytokines interleukin 1-beta (IL-1-beta), tumor necrosis factor alpha (TNF-alpha) and IL-6.

METHODS

Infants with birth weights < or =1250 g were prospectively enrolled. Samples were obtained from the endotracheal tube or nasopharynx on Day 1 and again between Days 7 and 10 for U. urealyticum culture. The concentrations of IL-1-beta, TNF-alpha and IL-6 were measured in tracheal aspirate samples by enzyme-linked immunosorbent assay.

RESULTS

There were 18 positive cultures for U. urealyticum from 15 of 96 infants (15.6%). IL-1-beta in tracheal aspirates expressed as concentration per volume or as a ratio of IL-1-beta to IL-6 were 7- and 14.9-fold higher, respectively, in Ureaplasma-positive infants than in Ureaplasma-negative infants (P < 0.05). The TNF-alpha/IL-6 ratio was 18.9 and 15.5 times higher in the Ureaplasma-positive aspirates than in the Ure aplasma-negative aspirates on Day 1 and Days 7 to 10 (P < 0.05). Concentrations of IL-1-beta and TNF-alpha were significantly correlated on Day 1 and Days 7 to 10. Although there was no clinical association demonstrated between U. urealyticum colonization and the development of bronchopulmonary dysplasia (BPD) in this study, infants who developed BPD had significantly higher IL-1-beta concentrations and ratios of IL-1-beta to IL-6 in Day 1 aspirates than infants who did not develop BPD. Conclusions. Isolation of U. urealyticum from the respiratory tract is associated with increased IL-1-beta concentrations and IL-1-beta-IL-6 ratios on Day 1 and increased TNF-alpha-IL-6 ratios on Days 1 and 7 to 10 in tracheal aspirates of colonized infants. Infants who developed BPD had higher IL-1-beta concentrations and IL-1-beta-IL-6 ratios, suggesting that these may be early markers of lung inflammation.

Nosocomial pneumonia caused by three genetically different strains of Legionella pneumophila and detection of these strains in the hospital water supply

A 44-year-old woman developed Legionella pneumophila pneumonia after cerebral surgery. Initially, one colony from a clinical specimen and two colonies from water samples, all belonging to serogroup 12, did not match when their DNA restriction patterns were compared. When additional colonies from the water specimens were analyzed, a serogroup 12 strain complementary to that found in the clinical specimen was identified. Other colonies from the clinical specimen were identified as serogroup 12 strains complementary to those identified from the water. In addition, the same serogroup 1 strain was isolated from the patient and the water system.

Cytokine autoantibodies in multiple sclerosis, aseptic meningitis and stroke

BACKGROUND

We have recently described the induction of anti-cytokine autoantibodies during bacterial infections and autoimmune diseases as a mechanism for cytokine regulation.

METHODS

Herein, we study the occurrence of autoantibodies to pro- and anti-inflammatory cytokines in cerebrospinal fluid and plasma from patients with multiple sclerosis, aseptic meningitis and stroke.

RESULTS

Increased levels of autoantibodies to interferon gamma, tumour necrosis factor alpha, interleukin 4 and interleukin 10 were detected in both compartments of multiple sclerosis and aseptic meningitis patients. Interestingly, in cerebrospinal fluid from stroke patients, only autoantibodies to interleukin 4 and interleukin 10, but not interferon alpha or tumour necrosis factor alpha were detected. No significant autoantibody levels were registered in plasma from stroke patients against all four cytokines compared with healthy control subjects. The latter revealed very low autoantibody levels in plasma and no detectable autoantibodies in cerebrospinal fluid.

CONCLUSIONS

Our data show for the first time the occurrence of cytokine autoantibodies in these diseases, but their biological significance is unclear.

The significance of the 3'-nontranslated region and E2 amino acid mutations in the virulence of Semliki Forest virus in mice

We have recently shown that the 3'-nontranslated region (3'-NTR) of the avirulent Semliki Forest virus A7(74) [SFVA7(74)] contains a unique sequence of 101 nucleotides and five repetitive nucleotide units whereas the 3'-NTR of the neurovirulent SFV4 has only two repeats. A chimeric virus was constructed by replacing the entire 3'-NTR of the SFV4 clone with the A7(74) 3'-NTR. The hybrid replicated efficiently in the central nervous system (CNS) of adult Balb/c mice and, similarly to SFV4, led to high mortality after intraperitoneal inoculation. In contrast, another chimeric virus, CME2, containing the E2 gene of the avirulent SFVA7(74) virus in the SFV4 clone was recently shown to be avirulent for mice. Several derivatives with single-site or a constellation of amino acid mutations were constructed. Two single-site E2 mutants, Val37lle and Asn212Ser, displayed an attenuated phenotype in mice with mortality reduced from 90 to 48 and 43%, respectively. None of the multiple site mutants were significantly attenuated. Adult female mice showed a greater resistance to SFV infection than male mice. The SFV hybrid viruses, CM3NTR and CME2, reached the CNS similarly to the parental viruses, but the single-site E2 mutants were only sporadically found in the CNS. We conclude that in mice the 3'-NTR does not play a significant role in the pathogenesis of Semliki Forest virus and that specific E2 amino acid mutations reduce the virulence, especially in female mice. The results additionally suggest that individual amino acid mutations in the E2 glycoprotein affect the efficiency of migration into the CNS.

Hepatitis C virus and renal transplantation

During the past 12 months additional evidence has emerged from several studies, indicating that hepatitis C virus infection is the most important liver disease after renal transplantation. A new, severe and rare entity called fibrosing cholestatic hepatitis can lead to early liver failure, although the most important complications appeared in the long-run. Encouraging results with ribavirin have been described. Although glomerular lesions and more severe infections can appear in hepatitis C virus patients, graft and patient survival rates in most series are similar to those in hepatitis-C-negative patients. Survival is also better among hepatitis-C-positive patients after renal transplantation than in hepatitis-C-positive patients on dialysis on the waiting list for transplantation. Finally, the use of kidneys from hepatitis-C-positive donors is suggested for transplant into hepatitis C RNA positive patients matching the hepatitis C genotype.

Evaluation of arbitrarily primed polymerase chain reaction analysis for typing Legionella pneumophila

OBJECTIVE: To evaluate the performance of arbitrarily primed polymerase chain reaction (AP-PCR) analysis in epidemiologic typing of Legionella pneumophila. METHODS: Sixty-two isolates of L. pneumophila of serogroups 1, 3, 6 and 10, including epidemiologically related and unrelated isolates, were analyzed by AP-PCR using the primer BG2. Twenty-six of the serogroup 1 isolates were typed by pulsed-field gel electrophoresis (PFGE). RESULTS: AP-PCR analysis showed 98% typeability and complete reproducibility. A majority of unrelated isolates of each serogroup could be distinguished (discrimination index: 92%). Clinical isolates showed AP-PCR patterns indistinguishable from those of the isolates of the related environmental source. PFGE and AP-PCR results were in agreement for 88% of isolates. CONCLUSIONS: Single-primer AP-PCR analysis can be used as a simple and reproducible screening method for typing L. pneumophila strains of different serogroups.

Comparison of a rapid culture method combining an immunoperoxidase test and a group specific anti-VP1 monoclonal antibody with conventional virus isolation techniques for routine detection of enteroviruses in stools

In order to shorten the time required for the detection of enteroviruses in stool specimens, an 18-h immunoperoxidase test combining low-speed centrifugation and the use of a group specific anti-VP1 monoclonal antibody (5-D8/1, Dako) was developed. This rapid culture assay (RCA) was compared blindly to a conventional culture assay (CCA) on a panel of 180 children's stool specimens received for routine diagnosis of enterovirus infection. The same cell lines (human embryonic fibroblasts and KB continuous cell line) were used in both tests. Discrepancies in results were analysed by a PCR technique with primers located in a conserved part of the 5' non-coding region of the enterovirus genome. Fourteen specimens were positive and 158 were negative with both tests. Four samples were positive with the RCA yet negative with the CCA and 3 others showed the opposite pattern; an additional sample positive by RCA was uninterpretable by CCA due to bacterial contamination. Subsequent PCR testing of these 8 samples showed no discrepancies; all were positive. Using CCA as the reference, the sensitivity and specificity of RCA were 77.8 and 98% respectively. Kinetic studies using enterovirus isolates demonstrated that RCA was much more sensitive than CCA during the first three days of culture. These results further suggested that RCA sensitivity could be improved by a factor of at least 10 times by prolonging the incubation period by 24 hr. With this change, the RCA assay described below is suggested as a rapid alternative to CCA for the routine diagnosis of enterovirus infection in stool specimens. When an identification at the serotype level is required, samples found positive using RCA could then be subjected to CCA.

Increased immunoglobulin G production by short term cultured duodenal biopsy samples from HIV infected patients

BACKGROUND

Secretory immunity is a major defence mechanism against infections at mucosal surfaces which are common in HIV infected patients.

AIMS

To analyse intestinal immunoglobulin production in HIV infection in comparison with that in saliva and serum.

PATIENTS AND METHODS

Immunoglobulin G (IgG), A (IgA), and M (IgM) concentrations were determined in supernatants of short term cultured duodenal biopsy samples, serum, and saliva from HIV infected patients (n = 28) and controls (n = 14) by radial immunodiffusion.

RESULTS

IgG was increased in the supernatants of short term cultured biopsy samples and saliva from HIV infected patients compared with controls (p < 0.01), but IgA and IgM levels were normal. In contrast, both IgG and IgA concentrations in serum were higher in HIV infected patients than in controls (p < 0.002). No correlation was found between IgA produced by duodenal biopsy specimens and serum IgA.

CONCLUSION

Abnormalities in mucosal immunoglobulin production in HIV infection were surprisingly small, indicating that specific secretory immunity rather than quantitative immunoglobulin production may be impaired. However, increased production of IgG could contribute to mucosal inflammation by complement activation. Our findings of normal mucosal IgA production and the lack of correlation between serum and mucosal IgA argues against an intestinal origin for the increased serum IgA levels in HIV infected patients.

Comparison of use of cerebrospinal fluid, serum, and throat swab specimens in diagnosis of enteroviral acute neurological infection by a rapid RNA detection PCR assay

A PCR assay for detection of enterovirus RNA in multiple specimen types from patients with neurological infections was evaluated. Combined PCR assay of cerebrospinal fluid and serum (systemic specimens) was more sensitive than assaying either specimen alone in children but not in adults. Compared with PCR in systemic specimens, detection of enterovirus RNA in throat swabs showed a sensitivity of 62.5% and a specificity of 75.6%.

Molecular typing of enteroviruses: current status and future requirements. The European Union Concerted Action on Virus Meningitis and Encephalitis

Human enteroviruses have traditionally been typed according to neutralization serotype. This procedure is limited by the difficulty in culturing some enteroviruses, the availability of antisera for serotyping, and the cost and technical complexity of serotyping procedures. Furthermore, the impact of information derived from enterovirus serotyping is generally perceived to be low. Enteroviruses are now increasingly being detected by PCR rather than by culture. Classical typing methods will therefore no longer be possible in most instances. An alternative means of enterovirus typing, employing PCR in conjunction with molecular genetic techniques such as nucleotide sequencing or nucleic acid hybridization, would complement molecular diagnosis, may overcome some of the problems associated with serotyping, and would provide additional information regarding the epidemiology and biological properties of enteroviruses. We argue the case for developing a molecular typing system, discuss the genetic basis of such a system, review the literature describing attempts to identify or classify enteroviruses by molecular methods, and suggest ways in which the goal of molecular typing may be realized.

Comparative analysis of infrequent-restriction-site PCR and pulsed-field gel electrophoresis for epidemiological typing of Legionella pneumophila serogroup 1 strains

Two methods were compared for the analysis of 48 unrelated and epidemiologically related Legionella pneumophila serogroup 1 isolates. These are the infrequent-restriction-site PCR (IRS-PCR) assay with adapters designed for XbaI and PstI restriction sites and the pulsed-field gel electrophoresis (PFGE) analysis determined after DNA restriction with SfiI. Both methods demonstrated a high level of discrimination with a similar capacity for differentiating 23 of the 24 unrelated isolates. PFGE analysis and IRS-PCR assay were both able to identify epidemiologically related isolates of L. pneumophila from three outbreaks. Hence, IRS-PCR assay appears to be a reproducible (intergel reproducibility, 100%) and discriminative (discriminatory index, > or = 0.996) tool for typing of Legionella. Compared to PFGE, however, IRS-PCR presented an advantage through ease of performance and with attributes of rapidity and sensitivity of target DNA.

Serologic responses to hepatitis C virus in solid organ transplant recipients

BACKGROUND

Hepatitis C (HCV) infection is known to have been transmitted by both blood transfusion and donor organs. We sought to determine the historical incidence of donor- and transfusion-acquired HCV infection in kidney transplant (RTx) and heart transplant (HTx) recipients at our center and to study the kinetics of seroconversion to HCV.

METHODS

A bank of sera collected from organ donors (388 RTx and 88 HTx) who received allografts between January 1984 and April 1992 was screened for anti-HCV using a third generation enzyme immunoassay. Recipient sera collected before transplant (preTx), at 1 year after transplant, and at last follow-up were tested. Fresh follow-up sera on all surviving anti-HCV-positive (+) RTx and HTx, all anti-HCV-negative (-) HTx, and a subset of 85 anti-HCV- RTx were assayed for HCV RNA using an reverse transcriptase-polymerase chain reaction assay.

RESULTS

Twenty-four of 388 RTx (6.2%) and 2 of 88 HTx (2.3%) were anti-HCV+ preTx. Eight of 218 (3.7%) organ donors were anti-HCV+. Six of the seven (85.7%) anti-HCV+ donors with adequate recipient follow-up transmitted HCV infection to one or more recipients. Nineteen of 313 RTx (6.1%) and 8 of 72 HTx (11.1%) with follow-up > or =1 year seroconverted to anti-HCV. One of 85 (1.2%) anti-HCV- RTx and 3 of 44 (6.8%) anti-HCV-HTx were HCV RNA+ when tested at last follow-up. Five cases of de novo HCV infection occurred after the introduction of first generation anti-HCV screening of donors. Persistent viremia (HCV RNA+) at last follow-up was observed in 70.6% (12/17) RTx anti-HCV+ preTx. Fourteen of 15 (93.3%) RTx and 9 of 9 (100%) HTx with de novo HCV infection had persistent viremia. Seroconversion was more delayed in HTx than RTx (P=0.0572, log-rank Mantel-Cox statistic) although both groups demonstrated an impaired humoral response to HCV when compared with the immunocompetent host.

CONCLUSIONS

Organ donor- and transfusion-acquired HCV infection was common in RTx and HTx transplanted before the introduction of second generation anti-HCV screening in 1992. Serologic responses to HCV are often delayed and sometimes absent in these patients. Assays for HCV RNA should be considered as a screening test for the detection of HCV infection in this population. Serologic responses to HCV were more impaired in HTx compared with RTx, which may reflect the more intensive immunosuppressive regimens given to HTx at our center.

Hepatitis C infection in transplantation

This review emphasizes the role of HCV in the transplant setting. Prolonged HCV infection results in end-stage liver disease and as such represents a common indication for liver transplantation. Recurrence of infection is almost universal after transplantation in those with viremia before transplantation. Acquired disease is uncommon but nevertheless important, particularly in organ populations in whom screening for infection is not routine. The natural history of post-transplantation disease suggests that the effect on graft or patient survival is minor, at least during short-term follow-up. Long-term follow-up is needed, as well as more detailed study of the factors contributing to severity of post-transplantation disease. Kidney transplant recipients are commonly infected with HCV prior to transplantation. HCV infection after transplantation is associated with an increased risk of liver disease and infectious complications, but its effect on survival is still controversial. Similarly, observations in recipients of other solid organ transplants, such as heart and lung, and bone marrow patients suggest that HCV infection usually is not a major cause of mortality in the first 5 to 10 years of follow-up. Many issues still need to be addressed. The most important is the identification of factors that contribute to disease progression. Finally, effective therapies to eradicate infection and prevent disease progression are awaited.

Epidemiological study of variations in beta-lactam antibiotic susceptibility of Pseudomonas aeruginosa in two intensive care units

A six-month prospective study was carried out in the medical and surgical intensive care units (ICUs) at Besançon University Hospital to assess the frequency and risk factors for beta-lactam-resistant isolates of Pseudomonas aeruginosa. Clinical samples were screened for P. aeruginosa, and four antibiograms were distinguished using imipenem and ceftazidime, namely: fully susceptible (SS), imipenem-resistant (RS), ceftazidime-resistant (SR), and resistant to both (RR). DraI restriction fragment length polymorphism of isolates from different patients or with different resistance patterns but the same serotype was assessed by pulsed-field gel electrophoresis. One hundred and twenty-one isolates were obtained from 50 of 281 patients, 60.3% were fully susceptible. 19.8% imipenem-resistant, 13.2% ceftazidime-resistant, and 6.6% resistant to both. Antibiotic-resistance was independent of serotype. Twenty-two of 32 imipenem-resistant isolates from six patients were of the same DNA type, and six other isolates from four patients were of a second DNA type. On only one occasion did a clonally defined strain develop imipenem resistance. By contrast ceftazidime-resistant strains had differing DNA types, but had been originally ceftazidime-susceptible in seven of 12 patients. Reversion of imipenem resistant strains to susceptibility occurred in one patient, and of ceftazidime-resistant strains in five patients. Case-control studies identified prior antibiotic therapy as a risk factor in colonization with resistant strains. Resistance to imipenem followed imipenem therapy, and resistance to ceftazidime followed use of weakly anti-pseudomonal beta-lactam antibiotics. The major route of spread of imipenem-resistant strains was cross-colonization. Thus, assuming appropriate isolation, a carbapenem should be preferred to an extended-spectrum cephalosporin to treat pseudomonas infections in ICU patients.

IgA immunity in HIV type 1-infected chimpanzees. I. Systemic immunity

HIV infection in humans causes various aberrancies in both the cellular and humoral immune systems, including functional abnormalities of B lymphocytes. In many instances, dysfunction occurs in the regulation of serum IgA, resulting in elevated concentrations of this immunoglobulin isotype. To determine whether HIV-1-infected chimpanzees develop IgA abnormalities similar to those observed in humans, we quantified total IgA, IgG, and IgM levels in sera collected longitudinally from six HIV-infected chimpanzees and one uninfected control animal. In comparison to immunoglobulin levels in the uninfected animal, two of the six infected chimpanzees exhibited increases in serum immunoglobulins following infection with HIV. Two other infected animals showed a marked decrease in the three isotypes within 10 months of exposure to HIV, followed by a return to baseline levels. The remaining two HIV-infected chimpanzees displayed serum immunoglobulin levels that paralleled the baseline levels and did not show great deviation over a period of 20 to 45 months postinfection. ELISA analyses of the IgA subclasses revealed possible abnormalities of the IgA2 subclass within the two animals that did not display irregular IgA, IgG, or IgM responses to HIV-1. Specific IgG, IgA, IgA1, and IgA2 antibodies to HIV antigens were detected by an enzyme immunoassay (EIA) kit and by Western blot analysis with IgA, IgA1, and IgA2 antibodies directed against the env, gag, and pol gene products. Because IgG can mask the detection of HIV-specific IgA antibodies in infected humans, Western blots and EIAs were also performed on IgG-depleted chimpanzee sera. The results demonstrated that in some instances, IgA reactivity against HIV antigens can be enhanced on removal of IgG. This study indicates that HIV-1 is capable of inducing abnormalities in serum IgA expression in chimpanzees. These results might further understanding of how HIV affects humoral responses in infected humans.

Molecular epidemiology of a nosocomial outbreak due to SHV-4-producing strains of Citrobacter diversus

Over a 6-month period, eight strains of Citrobacter diversus (Citrobacter koseri) resistant to extended-spectrum cephalosporins and monobactams were isolated from seven colonized and/or infected patients from the same intensive care unit. All strains harbored a single large conjugative plasmid which mediated an extended-spectrum beta-lactamase of the SHV-4 type (ceftazidimase phenotype; enzyme pI, 7.8; plasmid DNA hybridization with a blaSHV-specific probe). All strains were characterized by antibiotic resistance pattern analysis, beta-lactamase content analysis, plasmid profiling, ribotyping with EcoRI, and arbitrarily primed (AP)-PCR with primers O8 and O12. Among the eight C. diversus strains, strains Cd5 to Cd12, six isolates (isolates Cd6 to Cd11) were identical by all markers; one strain (strain Cd5) differed by two markers (antibiotype and AP-PCR pattern with primer O8), and the remaining strain (strain Cd12) differed by two other markers (ribotype and AP-PCR pattern with primer O12). Our results suggest that six of the eight SHV-4-producing C. diversus strains studied (strains Cd6 to Cd11) were a single epidemic strain. Strain Cd5 could be related to the epidemic strain; the origin of strain Cd12 remains uncertain.

Identification and DNA fingerprinting of Legionella strains by randomly amplified polymorphic DNA analysis

The randomly amplified polymorphic DNA (RAPD) technique was used in the development of a fingerprinting (typing) and identification protocol for Legionella strains. Twenty decamer random oligonucleotide primers were screened for their discriminatory abilities. Two candidate primers were selected. By using a combination of these primers, RAPD analysis allowed for the differentiation between all different species, between the serogroups, and further differentiation between subtypes of the same serogroup. The usefulness of RAPD analysis was also evaluated with outbreak-related clinical and environmental isolates previously typed by the restriction fragment length polymorphism technique. RAPD analysis proved to be as accurate as other genotypic methods, reproducible, and highly discriminatory and is a valuable new alternative to traditional fingerprinting and identification of Legionella species and strains.

Cell-surface interactions of echovirus 22

Echovirus 22 (EV22) is a picornavirus forming a distinct molecular cluster together with echovirus 23. EV22 has an Arg-Gly-Asp (RGD) peptide motif in its capsid protein VP1; similar motifs are known to mediate many cell-cell and microbe-host interactions. To identify peptide sequences that specifically bind to EV22 and potentially play a role in receptor recognition, we have used here peptide libraries displayed in filamentous phage. We isolated an EV22-binding motif CLRSG(R/F)GC. The synthetic CLRSGRGC peptide was able to inhibit EV22 infection. The infection was also inhibited by an RGD-containing peptide representing the C terminus of the EV22 capsid protein VP1 and CWDDGWLC (an RGD-binding peptide; Pasqualini, R., Koivunen, E., and Ruoslahti, E. (1995) J. Cell Biol. 130, 1189-1196). As the EV22-recognizing sequence LRSG is found in the integrin beta1 chain and the entire LRSGRG hexapeptide occurs in the matrix metalloproteinase 9 (MMP-9), we carried out blocking experiments with anti-integrin and anti-MMP-9 antibodies. EV22 infection could be blocked in cell cultures with anti-alphav, -beta1, and, to a lesser extent, with anti-MMP-9 antibodies. These results imply that EV22 recognizes preferentially alphavbeta1-integrin as a cellular receptor and MMP-9 may also play a role in the cell-surface interactions of the virus.

Detection of coxsackievirus B3 in intestinal tissue of orally-infected mice by a standardized RT-PCR assay

BACKGROUND

Previous studies have reported the role of enteroviruses in chronic diseases, using in-house RT-PCR protocols. A well-standardized PCR assay (Amplicor enterovirus, Produits Roche) designed for the diagnosis of enterovirus meningitis in cerebrospinal fluids (CSF) was recently described.

OBJECTIVES

To evaluate this commercially-available PCR assay for the detection of enterovirus in intestinal biopsies.

STUDY DESIGN

In order to obtain large quantities of infected material, eight mice were inoculated orally with 2 x 10(5) 50% tissue culture infective doses (TCID50) of coxsackievirus B3 (CBV3); two mice were sacrificed every day from day 1 to day 4 post-infection. Stool specimens and small bowel fragments were taken from infected animals and controls. Four protocols of RNA extraction from intestinal tissue were compared. Extracted RNA was then tested by the Amplicor assay and by a seminested in-house PCR.

RESULTS

The best results were obtained with a commercial reagent using a combination of guanidium thiocyanate and phenol (TRI Reagent, Sigma). This procedure allowed the detection of enteroviral RNA in intestinal samples of 7/8 and 8/8 infected mice by Amplicor assay and seminested PCR, respectively, whereas only five samples were tested positive by conventional cell culture. When tested on serial dilutions of CBV3 mixed with intestinal tissue, a sensitivity of 0.2 TCID50/mg was achieved with both PCR assays.

CONCLUSIONS

The data demonstrate that the Amplicor enterovirus assay, which is designed to avoid false-positive amplifications, can be used, with a slight modification of the RNA extraction step, for the detection of enterovirus in specimens different from CSF such as intestinal tissue.

RAPD fingerprinting for the distinction ofPrevotella intermediasensu stricto fromPrevotella nigrescens

A collection of 70 oral strains including reference strains and clinical isolates identified as Prevotella intermedia sensu lato was constituted to cover a large clinical and geographical diversity. Electrophoresis of the enzyme malate dehydrogenase allowed the identification of the 70 study strains as Prevotella intermedia sensu stricto (n= 36), Prevotella nigrescens (n= 31) and three unclassified strains. By using four primers, DNA fingerprints were generated from 20 strains as random amplified polymorphic DNA (RAPD). Matching co-migrating amplicon positions by pairwise comparison allowed the clustering of the fingerprints as two groups coincident with the P. intermedia/P. nigrescens assignment by enzyme electrophoresis of malate dehydrogenase. Our data suggest that isolates identified asP. intermedia sensu lato by conventional criteria can be speciated asP. intermedia sensu stricto or P. nigrescens by RAPD fingerprinting.

The first clinical isolate of Legionella parisiensis, from a liver transplant patient with pneumonia

A bluish white autofluorescent strain of Legionella was isolated from the tracheal aspirate of a female liver transplant patient who developed hospital-acquired pneumonia. This strain had biochemical characteristics compatible with those of L. cherrii, L. anisa, and L. parisiensis and could not be differentiated from L. bozemanii and L. parisiensis by the direct fluorescent-antibody assay. Phylogenetic analysis of partial 16S rRNA gene sequences of this strain (ATCC 700174) revealed the closest homology to the species L. parisiensis (99.5%). An L. parisiensis species-specific profile was also identified by a random amplified polymorphic DNA technique. This is the first report of L. parisiensis isolation from humans.

Pathophysiology of HIV-associated diarrhea

Considerable advances have been made in the evaluation and treatment of diarrhea in HIV-infected individuals, although gaps in knowledge still exist. The availability of newer and more powerful antiretroviral agents should allow a better definition of the effect of local HIV infection on intestinal function. Further attention to the pathophysiology of diarrhea should lead to improvements in diagnosis and treatment.

Neutralising and binding anti-interferon-beta-I b (IFN-beta-I b) antibodies during IFN-beta-I b treatment of multiple sclerosis

Interferon-beta-I b (IFN-beta-I b) is an immunomodulatory therapy of multiple sclerosis (MS), reducing the numbers and severity of exacerbations and the total lesion load measured by magnetic resonance imaging of the brain. The benefits of IFN-beta-I b could be hampered by the development of neutralising antibodies against the compound. Our results confirmed earlier studies, showing that 42% of MS patients treated with IFN-beta-I b for more than 3 months had developed neutralising antibodies. The occurrence of binding anti-IFN-beta-I b antibodies, presently not believed to impede the clinical efficacy of IFN-beta-I b, were demonstrated by an immunoassay in some patients after 1 month of treatment and in 78% after 3 months. The development of binding antibodies seemed to be an early phenomenon, preceding the appearance of neutralising antibodies. Antibodies crossreacting with IFN-beta-I a and natural IFN-beta were also found in a majority of IFN-beta-I b treated patients with high titres of binding antibodies. Employing a solid-phase enzyme-linked immunospot (ELISPOT) assay, 68% of MS patients treated with IFN-beta-I b for 1-23 months had elevated numbers of anti-IFN-beta-I b-antibody secreting cells in blood, compared to 18% of untreated MS patients and 20% among patients with other neurological diseases. Thus, our findings confirm that IFN-beta-I b is immunogenic in MS patients. High levels of anti-IFN-beta-I b antibody secreting cells were, however, also found in two untreated control patients with inflammatory diseases, suggesting that anti-IFN-beta-I b antibodies might also occur spontaneously.

Epidemiologically related and unrelated strains of Pseudomonas aeruginosa serotype O12 cannot be distinguished by phenotypic and genotypic typing

A clonal origin for European isolates of antibiotic multi-resistant Pseudomonas aeruginosa serotype O12 has been suggested. This study was designed to assess the value and limitations of several typing methods for the investigation of outbreaks due to this serotype. In Hôpital de Rodez, France, this organism is endemic, and a prospective clinical epidemiological study was undertaken over a 15 month period, encompassing all patients at the hospital from whom P. aeruginosa O12 was isolated. All isolates were examined by auxanogram, antibiogram, phage-typing, electrophoresis of esterases and pulsed-field gel electrophoresis of DNA. The results suggest that (1) the methods used did not clearly differentiate between clinically-related and epidemiologically-unrelated European isolates, (2) in Hôpital de Rodez, while some isolates were likely to have been transmitted from patient-to-patient, most infections or colonizations with this organism were sporadic and their origin is unknown. The limits of typing methods for the investigation of outbreaks of nosocomial infection with multi-resistant P. aeruginosa O12 are emphasized.

Salivary and mucosal immune responses to HIV and its co-pathogens

The profound effects that HIV induces in systemic immunity have been well characterised, but the situation with regard to mucosal immune responses is less clear. Oral cavity fluids have been used as a marker of the mucosal immune system. Whole and parotid saliva IgA, IgA1 and IgA2 concentrations have been found to be lower in both HIV infection and AIDS subjects, whereas serum IgA and IgA subclasses are markedly raised, suggesting a dichotomy between systemic and secretory immunity. Salivary antibodies to HIV can be readily detected and secretory IgA antibody can be neutralising to some strains of HIV. HIV vaccines can also induce antibody responses in saliva, but vaccination routes other than parenteral immunisation are needed. Antibody responses to oral microbes have also been studied and it has been shown that IgA, IgA1 and IgA2 subclass antibody titres to Candida albicans and to Streptococcus mutans are increased in whole or parotid saliva from HIV patients, but reduced in AIDS patients, suggesting a compensatory response which is overcome with progressive immunodeficiency. The avidity of salivary IgA antibodies to Candida in HIV seems unimpaired, whereas relative avidities of serum antibodies in HIV patients with candidiasis are lowered. Non-specific factors which may inhibit Candida and other opportunist pathogens are also found in saliva. The candidacidal, myelomonocytic protein calprotectin is present in saliva at levels which are biologically active, although levels are lowered in HIV infection. Overall, HIV infection appears to be associated with disregulation of a number of immune factors at the mucosal surface, but the ability of patients with HIV infection to mount specific antibody secretory responses seems to be relatively intact until late in infection.

Cytomegalovirus and simian immunodeficiency virus coinfection: longitudinal study of antibody responses and disease progression

Antibody titers to rhesus cytomegalovirus (RhCMV) were prospectively analyzed over a period of 68 weeks in a longitudinal serosurvey of 17 RhCMV-seropositive rhesus macaques (Macaca mulatta) experimentally coinfected with simian immunodeficiency virus (SIV). These were compared with anti-RhCMV titers in 18 animals that were also naturally infected with RhCMV but not infected with SIV. Fluctuations in anti-RhCMV antibody titers were observed within 5 weeks of SIV inoculation, and two distinct patterns of RhCMV antibody response were observed in SIV-infected animals. Animals showing a progressive decline in anti-RhCMV immunoglobulin G (IgG) exhibited the most rapid disease progression, coincident with low anti-SIV and anti-tetanus toxoid IgG responses, high levels of p27 antigen in the plasma, and short survival. Animals exhibiting a more stable CMV-specific response after SIV inoculation had the least rapid disease course. Anti-RhCMV antibody titers in SIV-uninfected animals remained relatively stable during the period of study. Evidence that preinoculation immunologic measures predicted postinoculation outcome was equivocal.

A nosocomial outbreak due to Enterobacter cloacae strains with the E. hormaechei genotype in patients treated with fluoroquinolones

During a 7-month period, we isolated 21 highly fluoroquinolone-resistant Enterobacter cloaecae strains in units from two hospitals in Marseille, France. Random amplification of polymorphic DNA showed clonal identity between isolates which, furthermore, presented the Enterobacter hormaechei genotype on DNA-DNA hybridization. The emergence of this clone was observed only in patients treated with fluoroquinolones.

Computerized restriction endonuclease analysis compared with O-serotype and phage type in the epidemiologic fingerprinting of Pseudomonas aeruginosa strains

OBJECTIVE: To assess restriction endonuclease analysis (REA) of chromosomal DNA using SalI enzyme, low-concentration (0.4%) agarose gels and digitalized data management of the REA patterns obtained for the typing of clinical Pseudomonas aeruginosa isolates. METHODS: A group of 67 clinical unrelated isolates from 10 Spanish hospitals was used to study the discriminatory power, reproducibility and typeability of REA typing. RESULTS: A SalI REA pattern consisted of a variety (1--10) of restriction bands in the range between 12.2 and 48.5 kb and an unresolvable smear of low-molecular-weight bands. Forty different SalI REA patterns with an index of discrimination of 0.979 were obtained. Low typeability (91.04%) was the major limitation of REA typing. Analysis of blinded subcultures of eight Pseudomonas aeruginosa strains showed the reproducibility of REA typing to be 87.5%. Combined phenotypic typing (O-serotyping and phage typing) performed on the same group of strains showed comparable discrimination but much lower reproducibility. Isolates selected from five clusters of nosocomial infections in hospitals in the UK were typed by REA typing, and the results show high agreement when compared with conventional phenotypic typing methods in distinguishing between strains. CONCLUSIONS: These data underline the usefulness of REA typing enhanced with digitalized data management for the epidemiologic subtyping of clinical Pseudomonas aeruginosa isolates.

Identification of Streptococcus species by randomly amplified polymorphic deoxyribonucleic acid fingerprinting

Identification of Streptococcus species isolated from bovine milk by randomly amplified polymorphic DNA fingerprinting was evaluated. Bacterial DNA templates were prepared using a standardized method for randomly amplified polymorphic DNA amplification and previously evaluated arbitrary primers. Amplified DNA fragments were visualized by agarose gel electrophoresis and were analyzed by densitometry. Unidentified streptococci (n = 163) that were isolated from mammary secretions of dairy cows were evaluated. The DNA fingerprint patterns of unidentified bacteria were compared using a computerized database that contained DNA fingerprint patterns of test strains. Comparison with the API 20 Strep identification system (bioMérieux Vitek, Inc., Hazelwood, MO) and conventional biochemical tests showed that about 91% of isolates (148 of 163) were identified correctly by DNA fingerprinting. The sensitivity of the DNA fingerprinting technique was 90%, and the specificity was 92%. However, the DNA fingerprinting technique only identified 4 of the 11 species included in the study. Three of the 4 species, Streptococcus uberis, Streptococcus agalactiae, and Streptococcus dysgalactiae, represent the streptococci isolated most frequently from cows with mastitis. The other Streptococcus and Enterococcus species that were not identified by the DNA fingerprinting system are less frequently isolated as causative agents of mastitis. Expanding the DNA fingerprint database would likely increase the sensitivity and specificity of this technique.

Distinct genotypic clusters of heterogeneously and homogeneously methicillin-resistant Staphylococcus aureus from a Greek hospital

Methicillin-resistant Staphylococcus aureus (MRSA) strains isolated over a one-year period from a Greek hospital were tested for their levels of resistance to methicillin by population analysis. Heterogeneously resistant strains belonged to classes I, II, and II/III, whereas homogeneously resistant ones belonged to class IV. Strains of all classes possessed the mecA gene. Pulsed-field gel electrophoresis (PFGE) of Smal-digested genomic DNA revealed that all heterogeneously resistant strains were also closely related, but in a cluster distinct from the heterogeneous one. The methicillin-sensitive strains displayed a greater variety of PFGE types compared to MRSA isolates.

Anti-cytokine autoantibodies: epiphenomenon or critical modulators of cytokine action

Low amounts of high-affinity autoantibodies to various cytokines have been detected in sera from healthy donors. Their levels, although highly variable, are increased in the circulation of patients subjected to cytokine therapy or suffering from a variety of immunoinflammatory diseases. It has been suggested that these autoantibodies play a regulatory role in the intensity and duration of an immune response. The antibodies may prevent the binding of a cytokine to its specific cell surface receptor thereby neutralizing its biological activity in vivo. They may also act as carrier proteins preventing the rapid elimination of a cytokine from the circulation and thus increase its bioactivity. Additionally or alternatively, autoantibodies may modulate cytokine-induced intracellular signal transduction pathways or trigger complement-mediated cytotoxicity towards cells carrying membrane-bound cytokines. The autoantibodies may exert their regulatory role in compliance with the other factors that control cytokine activity, including soluble cytokine receptors, cell surface decoy receptors, and receptor antagonists. Although not favored by many investigators, a less sophisticated role for naturally occurring anti-cytokine autoantibodies should be considered as well. Recent evidence has shown that autoantibodies are generated at a high frequency as part of a response to foreign antigens. These antibodies are produced by B cells arising from the process of somatic mutation. Thus anti-cytokine autoantibodies may be the result of a "leaky" B cell response triggered by immunoinflammatory processes. High-titered autoantibodies induced by cytokine therapy are of clinical concern since their occurrence is often associated with the loss of response to treatment. Moreover, they may also neutralize endogenously produced cytokines with possible pathological consequences. In this paper we have reviewed the available information on the biological and clinical significance of both naturally occurring and therapeutically induced anti-cytokine autoantibodies in animals and man with the emphasis on antibodies directed to interferons.

Arbitrary primed PCR fingerprinting and serotyping of clinical Pseudomonas aeruginosa strains

Arbitrary primed PCR (AP-PCR) analysis was compared with serotyping as a means of high-resolution typing of Pseudomonas aeruginosa. Seventy-four isolates from 3 different hospitals and 18 reference strains were studied. Serotyping provided good index of discrimination, although eleven isolates could not be serotyped. Genomic DNA was amplified with a single 10 nucleotide primer (sequence 5'-AGG GGT CTT G-3'). The strains were genetically diverse and 61 different AP-PCR profiles of 2-7 bands between 0.3 and 2.4 kb were obtained. AP-PCR profiles were not consistently associated with serotypes, but they clearly subtyped strains of the same serotype. Numerical analysis of AP-PCR patterns defined 7 groups at the 55% similarity level, and identified predominant strains in each hospital. The results show that AP-PCR analysis provides a simple and practical approach to typing P. aeruginosa that is more discriminatory than traditional serotyping scheme. We suggest that maximum discrimination can be achieved by a combination of both methods.