Nosocomial colonization of premature babies with Klebsiella oxytoca: probable role of enteral feeding procedure in transmission and control of the outbreak with the use of gloves

OBJECTIVE

To investigate the persistence of colonization of premature babies by Klebsiella oxytoca, with special emphasis on the mode of transmission of the bacterium and evaluation of Standard Precautions to stop the epidemic.

DESIGN

Retrospective analysis of cases and prospective study of systematic bacteriological samples (stools and throat) from babies, healthcare workers (HCWs), and environment, with genotyping of strains by arbitrarily primed polymerase chain reaction.

SETTING

A premature baby unit (PBU) and a neonatal intensive care unit in the university hospital of Saint-Etienne, France.

RESULTS

An outbreak of K oxytoca was suspected in two pediatric wards after the occurrence of a fatal bacteremia in a newborn hospitalized in the PBU and the colonization of other babies 2 months later. Retrospective analysis showed that 24 babies' digestive tract had been colonized. No environmental reservoir was recovered in the units nor in enteral feeding. No K oxytoca was isolated from HCW samples. Genotyping confirmed the presence of epidemic strains, although independent clones were responsible for infections or colonizations in each of the two units. The chronology and the site of babies' colonization (isolation of K oxytoca in stools before throat) were determined during a prospective study and suggested that enteral feeding procedures could be the source of contamination. Therefore, use of gloves during this practice by HCWs was recommended and, after readjustment of Standard Precautions, stopped the outbreak.

CONCLUSION

To prevent cross-contamination among high-risk babies, careful attention must be paid to Standard Precautions. Bacteriological surveillance of the digestive tract of neonates could help to check compliance with these guidelines

Role of Siglec-7 in apoptosis in human platelets

BACKGROUND

Platelets participate in tissue repair and innate immune responses. Sialic acid-binding immunoglobulin-like lectins (Siglecs) are well-characterized I-type lectins, which control apoptosis.

METHODOLOGY/PRINCIPAL FINDINGS

We characterized the expression of Siglec-7 in human platelets isolated from healthy volunteers using flow cytometry and confocal microscopy. Siglec-7 is primarily expressed on α granular membranes and colocalized with CD62P. Siglec-7 expression was increased upon platelet activation and correlated closely with CD62P expression. Cross-linking Siglec-7 with its ligand, ganglioside, resulted in platelet apoptosis without any significant effects on activation, aggregation, cell morphology by electron microscopy analysis or secretion. We show that ganglioside triggered four key pathways leading to apoptosis in human platelets: (i) mitochondrial inner transmembrane potential (ΔΨm) depolarization; (ii) elevated expression of pro-apoptotic Bax and Bak proteins with reduced expression of anti-apoptotic Bcl-2 protein; (iii) phosphatidylserine exposure and (iv), microparticle formation. Inhibition of NAPDH oxidase, PI3K, or PKC rescued platelets from apoptosis induced by Siglec-7 recruitment, suggesting that the platelet receptors P2Y1 and GPIIbIIIa are essential for ganglioside-induced platelet apoptosis.

CONCLUSIONS/SIGNIFICANCE

The present work characterizes the role of Siglec-7 and platelet receptors in regulating apoptosis and death. Because some platelet pathology involves apoptosis (idiopathic thrombocytopenic purpura and possibly storage lesions), Siglec-7 might be a molecular target for therapeutic intervention/prevention.

Role of influenza vaccination in the elderly during an epidemic of A/H1N1 virus in 1988-1989: clinical and serological data

During a winter epidemic of A/H1N1 influenza virus, we evaluated the protection conferred by vaccination of 285 residents of a nursing home. Fifteen of 204 members of the nursing staff were also vaccinated. Serological determinations were performed before and after vaccination using radial hemolysis (RH) and neuraminidase inhibition (NI) tests. In the outbreak period, only one influenza case was noted in the vaccinated elderly and none among the vaccinated nursing staff. On the other hand, 38 cases (20%) occurred in the unvaccinated hospital personnel. Twenty-one percent of the elderly people exhibited seroconversion to the vaccinal strain by RH and NI while 27 and 20% of the vaccinated nursing staff seroconverted by the same tests, respectively. Thus, the clinical protection conferred by influenza vaccination was excellent and much greater than expected from serological results.

Measure of viral load by using the Abbott Real-Time HIV-1 assay on dried blood and plasma spot specimens collected in 2 rural dispensaries in Cameroon

BACKGROUND

This study aimed to evaluate the use of dried blood spots (DBSs) and dried plasma spots (DPSs) locally collected in 2 rural dispensaries in Cameroon for the quantification of HIV-1 RNA.

METHODS

Forty-one subjects were sampled and spots of whole blood and plasma were deposited onto Whatman 903 cards and dried at ambient temperature under local conditions. Two sets of DBS and DPS cards were done per patient. The rest of the liquid plasma (LP) was frozen until use. LPs were tested at the "Chantal Biya" International Reference Centre (Yaoundé, Cameroon) by the Abbott Real-Time HIV-1 assay (Abbott Molecular Diagnostics, Wiesbaden, Germany). One series of DBS and DPS was transported and tested between 2 and 6 weeks later at the Virology Laboratory of Saint-Etienne (France). The second series was routed by mail and tested after up to 3 months of storage at ambient temperature.

RESULTS

From the first series, the correlation rate between viral loads obtained from LP and DBS, and from LP and DPS, was 0.98 and 0.99, respectively; specificity of DBS and DPS results was 100%. The results obtained from the second series indicate a great stability of DBS after long-term storage.

CONCLUSION

This study demonstrates that DBSs collected under local conditions in resource-limited settings are suitable for the differed quantification of HIV-1 RNA.

Epidemiologic and molecular investigations of genital mycoplasmas from women and neonates at delivery

The rates of colonization by Ureaplasma urealyticum and Mycoplasma hominis were evaluated in 208 women at delivery and in their neonates. Mycoplasmas were isolated from the cervicovaginal specimens of 100 mothers (48.1%) and from the gastric secretions of 40 neonates (19.2%). The prevalences of U. urealyticum and M. hominis were 47.6% and 11.0% in women and 19.2% and 1.0% in neonates, respectively. Premature rupture of membranes was significantly associated with colonization of women by U. urealyticum (P = 0.031), and colonization of their neonates by U. urealyticum (P = 0.002) and/or M. hominis (P = 0.023). Forty-four selected strains of mycoplasmas were further characterized by arbitrarily primed polymerase chain reaction. All strains of U. urealyticum belonged to the parvo biovar of the species. Arbitrarily primed polymerase chain reaction demonstrated the similarity of strains isolated from mother-neonate pairs, confirming the importance of vertical transmission of mycoplasmas at delivery.

Evaluation of a total core antigen assay for the diagnosis of hepatitis C virus infection in hemodialysis patients

Hemodialysis patients are recognized as a group at high risk of infection with hepatitis C virus (HCV). Therefore, such a population should be screened routinely for the presence of HCV viremia. Since nucleic acid techniques remain expensive and largely unavailable in many laboratories in the developing world, the present study assesses the clinical usefulness of the HCV core antigen enzyme immunoassay for the diagnosis of HCV infection in dialysis patients. One hundred seventy-five dialysis patients were screened for the presence of anti-HCV antibodies and HCV RNA in the serum. One hundred twenty-eight serum samples were collected from the 76 patients who were anti-HCV antibody- and/or HCV RNA-positive. These were evaluated for total HCV core antigen. Of these samples, 55 had sufficient volume to be further tested to quantify HCV RNA by reverse transcription polymerase chain reaction (RT-PCR). Genotyping of the HCV strains showed that the majority belonged to genotype 1b (77%). The HCV core antigen assay showed a sensitivity and specificity of 84% and 89%, respectively. The use of core antigen assay has enabled the early detection of three patients who developed an acute hepatitis C infection during the period of study. A correlation study was undertaken between the quantitative values of viral load, expressed as pg/ml of HCV core antigen in serum, and viral RNA in UI/ml. A significant correlation was observed (Pearson's correlation coefficient: 0.552; P<0.001). In conclusion, detection of HCV core antigen in serum is an inexpensive, reliable, and highly specific assay that can be useful in most laboratory settings to diagnose HCV infection, and especially in laboratories where nucleic acid technologies are not yet available.

A computerized prediction model of hazardous inflammatory platelet transfusion outcomes

BACKGROUND

Platelet component (PC) transfusion leads occasionally to inflammatory hazards. Certain BRMs that are secreted by the platelets themselves during storage may have some responsibility.

METHODOLOGY/PRINCIPAL FINDINGS

First, we identified non-stochastic arrangements of platelet-secreted BRMs in platelet components that led to acute transfusion reactions (ATRs). These data provide formal clinical evidence that platelets generate secretion profiles under both sterile activation and pathological conditions. We next aimed to predict the risk of hazardous outcomes by establishing statistical models based on the associations of BRMs within the incriminated platelet components and using decision trees. We investigated a large (n = 65) series of ATRs after platelet component transfusions reported through a very homogenous system at one university hospital. Herein, we used a combination of clinical observations, ex vivo and in vitro investigations, and mathematical modeling systems. We calculated the statistical association of a large variety (n = 17) of cytokines, chemokines, and physiologically likely factors with acute inflammatory potential in patients presenting with severe hazards. We then generated an accident prediction model that proved to be dependent on the level (amount) of a given cytokine-like platelet product within the indicated component, e.g., soluble CD40-ligand (>289.5 pg/109 platelets), or the presence of another secreted factor (IL-13, >0). We further modeled the risk of the patient presenting either a febrile non-hemolytic transfusion reaction or an atypical allergic transfusion reaction, depending on the amount of the chemokine MIP-1α (<20.4 or >20.4 pg/109 platelets, respectively).

CONCLUSIONS/SIGNIFICANCE

This allows the modeling of a policy of risk prevention for severe inflammatory outcomes in PC transfusion.

Pregnancy after safe IVF with hepatitis C virus RNA-positive sperm

In France, assisted reproductive technology (ART) for hepatitis C virus (HCV)-infected patients is now subject to strict control after the publication of recent guidelines. Infertile serodiscordant couples (HCV-viraemic men and their seronegative female partners) require special care to carried out in designated 'viral risk' laboratories. Twelve sequential semen samples taken from an HCV chronically infected patient were analysed within 22 months. HCV RNA was detected in all the seminal plasma sampled before antiviral treatment with relatively high viral loads, and in two of the corresponding fractions of motile sperm obtained after a gradient selection, suggesting that a contamination risk by HCV through ART cannot be excluded. When the selection of sperm on a discontinuous gradient was followed by an additional swim-up step, HCV RNA was never detected in the motile sperm suspension that was frozen in highly secure straws. IVF was performed using cryopreserved sperm that tested negative for HCV RNA, resulting in a pregnancy. One month after embryo transfer, testing for HCV RNA and antibodies in the woman gave negative results.

Natural recombination event within the capsid genomic region leading to a chimeric strain of human enterovirus B

Recombination between two strains is a known phenomenon for enteroviruses replicating within a single cell. We describe a recombinant strain recovered from human stools, typed as coxsackievirus B4 (CV-B4) and CV-B3 after partial sequencing of the VP1 and VP2 coding regions, respectively. The strain was neutralized by a polyclonal CV-B3-specific antiserum but not by a CV-B4-specific antiserum. The nucleotide sequence analysis of the whole structural genomic region showed the occurrence of a recombination event at position 1950 within the VP3 capsid gene, in a region coding for the 2b antigenic site previously described for CV-B3. This observation evidences for the first time the occurrence of an interserotypic recombination within the VP2-VP3-VP1 capsid region between two nonpoliovirus enterovirus strains. The neutralization pattern suggests that the major antigenic site is located within the VP2 protein.

Platelet components associated with adverse reactions: predictive value of mitochondrial DNA relative to biological response modifiers

BACKGROUND

Biological response modifiers (BRMs), secreted by platelets (PLTs) during storage, play a role in adverse events (AEs) associated with transfusion. Moreover, mitochondrial DNA (mtDNA) levels in PLT components (PCs) are associated with AEs. In this study we explore whether there is a correlation between pathogenic BRMs and mtDNA levels and whether these markers can be considered predictors of transfusion pathology.

STUDY DESIGN AND METHODS

We investigated a series of reported AEs after PC transfusion, combining clinical observations and mathematical modeling systems.

RESULTS

mtDNA was consistently released during the first days of PC storage; however, mtDNA release was earlier in "pathogenic" than in nonpathogenic PCs. PC supernatants with high levels of mtDNA along with soluble CD40 ligand (sCD40L) were significantly associated with occurrences of AEs. The fact that mtDNA did not associate with the 14 BRMs tested suggests the role of mtDNA in PC transfusion-linked inflammation is independent of that of BRMs, known to be associated with AEs. We present evidence that PLTs generate distinct pathogenic secretion profiles of BRMs and mtDNA. The calculated area under the curve for mtDNA was significantly associated with AEs, although less stringently predictive than those of sCD40L or interleukin-13, standard predictors of AE. The established model predicts that distinct subtypes of AEs can be distinguished, dependent on mtDNA levels and PC storage length.

CONCLUSIONS

Further work should be considered to test the propensity of mtDNA in PLT concentrates to generate inflammation and cause an AE.

Detection and characterization of hepatitis C virus RNA in seminal plasma and spermatozoon fractions of semen from patients attempting medically assisted conception

To investigate the risk of transmission of hepatitis C virus (HCV) via semen in assisted reproduction techniques, semen samples from 32 men chronically infected with HCV attending a center for assisted procreation were tested for HCV RNA by a reverse transcription-PCR protocol by using a modified version of the Cobas AMPLICOR HCV assay (version 2.0; Roche Diagnostics). The sensitivity of the test was 40 copies/ml. Four of 32 seminal plasma samples (12.5%) were found to be positive for the presence of HCV RNA. The median HCV load in blood was significantly higher in patients who were found to be positive for the presence of HCV RNA in semen than in those who tested negative (P = 0.02). In one man, seven consecutive seminal plasma samples tested positive for HCV RNA, as did two consecutive motile spermatozoon fractions; the corresponding fractions obtained after migration of the spermatozoa remained negative. Despite the absence of the proven infectivity of virus in semen samples that test positive for HCV RNA, these findings highlight the fact that seminal fluid may exhibit prolonged HCV RNA excretion. The usefulness of HCV RNA detection in both seminal plasma and spermatozoon fractions before the start of a program of medically assisted reproduction in couples in whom the male partner is chronically infected with HCV would need to be evaluated prospectively with a larger population of subjects exhibiting HCV RNA in their semen.

LPS stimulation of purified human platelets is partly dependent on plasma soluble CD14 to secrete their main secreted product, soluble-CD40-Ligand

BACKGROUND

Platelets are instrumental to primary haemostasis; in addition, as they are central to endothelium vascular repair, they play a role in physiological inflammation. Platelets have also been demonstrated to be key players in innate immunity and inflammation, expressing Toll-like receptors (TLRs) to sense microbial infection and initiate inflammatory responses. They are equipped to decipher distinct signals, to use alternate pathways of signalling through a complete signalosome, despite their lack of a nucleus, and to adjust the innate immune response appropriately for pathogens exhibiting different types of 'danger' signals. Previous work has described the two main LPS isoforms-TLR4 activation pathways in purified platelets. However, the precise mechanism of TLR4 signalling in platelets is not completely unravelled, especially how this signalling may occur since platelets do not express CD14, the TLR4 pathophysiological companion for LPS sensing. Thus, we investigated from what source the CD14 molecules required for TLR4 signalling in platelets could come.

RESULTS

Here we show that CD14, required for optimal response to LPS stimulation, is obtained from plasma, but used with restrictive regulation. These data add to the body of evidence that platelets are closer to regulatory cells than to first line defenders. The readout of our experiments is the canonical secreted cytokine-like protein, soluble (s)CD40L, a molecule that is central in physiology and pathology and that is abundantly secreted by platelets from the alpha-granules upon stimulation.

CONCLUSIONS

We show that sCD14 from plasma contributes to LPS/TLR4 signalling in platelets to allow significant release of soluble CD40L, thereby elucidating the mechanism of LPS-induced platelet responses and providing new insights for reducing LPS toxicity in the circulation.

Cytomegalovirus and Inflammatory Bowel Diseases (IBD) with a Special Focus on the Link with Ulcerative Colitis (UC)

Cytomegalovirus (CMV) infects approximately 40% of adults in France and persists lifelong as a latent agent in different organs, including gut. A close relationship is observed between inflammation that favors viral expression and viral replication that exacerbates inflammation. In this context, CMV colitis may impact the prognosis of patients suffering from inflammatory bowel diseases (IBDs), and notably those with ulcerative colitis (UC). In UC, the mucosal inflammation and T helper cell (TH) 2 cytokines, together with immunomodulatory drugs used for controlling flare-ups, favor viral reactivation within the gut, which, in turn, increases mucosal inflammation, impairs corticoid and immunosuppressor efficacy (the probability of steroid resistance is multiplied by more than 20 in the case of CMV colitis), and enhances the risk for colectomy. This review emphasizes the virological tools that are recommended for exploring CMV colitis during inflammatory bowel diseases (IBD) and underlines the interest of using ganciclovir for treating flare-ups associated to CMV colitis in UC patients.

Detection of enterovirus in human skeletal muscle from patients with chronic inflammatory muscle disease or fibromyalgia and healthy subjects

Enterovirus RNA has been found previously in specimens of muscle biopsy from patients with idiopathic dilated cardiomyopathy, chronic inflammatory muscle diseases, and fibromyalgia or chronic fatigue syndrome (fibromyalgia/chronic fatigue syndrome). These results suggest that skeletal muscle may host enteroviral persistent infection. To test this hypothesis, we investigated by reverse transcription-polymerase chain reaction (RT-PCR) assay the presence of enterovirus in skeletal muscle of patients with chronic inflammatory muscle diseases or fibromyalgia/chronic fatigue syndrome, and also of healthy subjects. Three of 15 (20%) patients with chronic inflammatory muscle diseases, 4 of 30 (13%) patients with fibromyalgia/chronic fatigue syndrome, and none of 29 healthy subjects was found positive. The presence of VP-1 enteroviral capsid protein was assessed by an immunostaining technique using the 5-D8/1 monoclonal antibody; no biopsy muscle from any patient or healthy subject was found positive. The presence of viral RNA in some muscle biopsies from patients exhibiting muscle disease, together with the absence of VP-1 protein, is in favor of a persistent infection involving defective viral replication.

Epidemiology and microbiological investigations of community-acquired pneumonia in children admitted at the emergency department of a university hospital

BACKGROUND

The management of children with community-acquired pneumonia (CAP) is largely influenced by the development of new molecular diagnostic tests that allow the simultaneous detection of a wide range of pathogens.

OBJECTIVES

Evaluation of a diagnostic approach including multiplex PCR assays for revisiting the epidemiology and etiology of CAP in children at hospital.

STUDY DESIGN

Children of all ages consulting at the Emergency Department of the University hospital of Saint-Etienne, France, during the 2012-2013 winter period were included. In addition to bacterial cultures, the following pathogens were detected using biplex commercially-available rt-PCR tests: adenovirus, respiratory syncytial virus, human metapneumovirus, bocavirus, rhinovirus/enterovirus, coronavirus, influenza viruses A and B, parainfluenza viruses, Mycoplasma pneumoniae and Chlamydophila pneumonia.

RESULTS

From 85 patients with CAP, at least one pathogen was identified in 81 cases (95.3%), including 4 bacterial exclusive infections (4.7%), 53 viral exclusive infections (62.4%) and 24 mixed infections (28.2%). Coinfection by at least two viruses was observed in 37 cases (43.5%). Mean age was higher in the case of documented bacterial infection (P<0.05). In the subgroup of viral exclusive infection, the mean age of severe cases was 2.0 years vs 3.8 years in mild and moderate cases (P<0.05).

CONCLUSIONS

These findings highlight the huge proportion of CAP of viral origin, the high number of co-infection by multiple viruses and the low number of bacterial CAP, notably in children under 5 years, and address the need to re-evaluate the indications of empiric antimicrobial treatment in this age group.

Better detection of Staphylococcus aureus nasal carriage by use of nylon flocked swabs

Flocked swabs (Copan) were compared to rayon swabs (Copan) for the nasal detection of Staphylococcus aureus in 90 healthy volunteers sampled sequentially during a 5-week period. The use of flocked swabs improved the number of nasal carriers (P = 0.026), the number of positive specimens (P = 0.01), and the quantity of bacteria in positive samples (P = 0.004).

Efficacy of environmental measures to decrease the risk of hospital-acquired aspergillosis in patients hospitalised in haematology wards

This study evaluated a multidisciplinary strategy to decrease the rate of invasive pulmonary aspergillosis (IPA) among adult patients hospitalised in two haematology wards in a single 560-bed building at the University Hospital of Saint-Etienne. Upgrading of the air filtration system and construction of an air-lock chamber at the entrance to the unit were completed during 1994. In 1995, specific hygienic measures were introduced during hospital building work, including the use of plastic barriers, watering during demolition work, reduction of pedestrian traffic in construction areas, and the wearing of high-efficiency filtration masks by immunosuppressed patients when outside the protected unit. This strategy was evaluated by a prospective survey of IPA cases between 1993 and 2001, coupled with environmental surveillance. The number and risk-level of hospital renovation projects increased between 1995 and 2001 (p < 0.01). In parallel, the rate of IPA decreased globally in the haematology unit from 0.85% (1.19/1,000 patients) in 1993 to 0.28% (0.21/1,000 patients) in 2001. The incidence of IPA decreased significantly between 1993-1996 and 1997-2001 (p 0.02, Mann-Whitney test). These results show that a multidisciplinary approach involving engineers, infection control practitioners, mycologists and clinicians enables IPA rates among patients hospitalised in haematology wards to be significantly decreased.

Identification of two subpopulations of purified human blood B cells, CD27- CD23+ and CD27high CD80+, that strongly express cell surface Toll-like receptor 9 and secrete high levels of interleukin-6

B-cell expression of certain Toll-like receptors (TLRs) is important in linking innate and adaptive immune responses in normal and pathological conditions. The expression of TLR9 plays a role in the recognition of conserved pathogen motifs in a manner that is dependent on B-cell localization, deduced from B-cell phenotype. The nature of TLR9 function is unclear. A first step in unravelling the function of this pattern recognition receptor is to discover the precise nature of the cell types that express TLR9. This study used three-colour flow cytometry to characterize the B lymphocytes from human peripheral blood mononuclear cells (PBMCs) that express TLR9 on the surface. We sorted TLR9-positive B and non-B cells from the PBMC population and detected TLR9 expression on naïve and memory B cells. Moreover, we identified two discrete subpopulations of B cells: CD19(+) CD27(-) CD23(+) cells and CD19(+) CD27(high) CD80(+) cells. These subpopulations expressed high levels of membrane TLR9 and exhibited a strong in vitro response to binding a relevant CpG motif by secreting high levels of interleukin-6 (compared to controls). Our finding that this pattern recognition receptor is expressed on a variety of cell subsets adds to the current understanding of the functional complexity of B-cell membrane TLR9.

Neutralization of human immunodeficiency virus type 1 (HIV-1) mediated by parotid IgA of HIV-1-infected patients

Infection with human immunodeficiency virus type 1 (HIV-1) has been shown to elicit a serum antibody response with neutralizing activity against T cell line-adapted HIV strains and primary HIV-1 isolates. Mucosal surfaces are the primary route of HIV-1 infection. Evidence is presented here for the presence of HIV-neutralizing antibodies in secretions. Infection of mucosal cells with HIV stimulates systemic and mucosal immune responses and results in the generation of neutralizing antibodies. Serum IgG and IgA neutralize HIV-1MN infection of susceptible T cell lines; serum IgG inhibits more effectively. Mucosal IgA purified from parotid saliva of HIV-1-seropositive individuals could neutralize both a T cell line-adapted strain and a primary isolate. The neutralizing activity of IgA was not directed against the anti-third-variable-loop or the anti-ELDKWA epitope. Thus, the specificity of mucosal IgA for HIV-1 neutralization epitopes remains to be determined and may provide insight into development of a mucosal vaccine.

Relationship between human immunodeficiency virus (HIV-1) infection and chronic periodontitis

Current studies show that, even in the era of antiretroviral therapies, HIV-1 infection is associated with more severe and frequent refractory chronic periodontitis. Areas covered: This review, based on a systematic analysis of the literature, intends to provide an update on factors that may be involved in the pathogenesis of periodontal disease in HIV-1-infected patients, including local immunosuppression, oral microbial factors, systemic inflammation, salivary markers, and the role of gingival tissue as a possible reservoir of HIV-1. Expert commentary: The therapeutic revolution of ART made HIV-1 infection a chronic controllable disease, reduced HIV-1 mortality rate, restored at least partially the immune response and dramatically increased life expectancy of HIV-1-infected patients. Despite all these positive aspects, chronic periodontitis assumes an important role in the HIV-1 infection status for activating systemic inflammation favoring viral replication and influencing HIV-1 status, and also acting as a possible reservoir of HIV-1. All these issues still need to be clarified and validated, but have important clinical implications that certainly will benefit the diagnosis and management of chronic periodontitis in HIV-1-infected patients, and also contributes to HIV-1 eradication.

Emergence of quinolone-imipenem cross-resistance in Pseudomonas aeruginosa after fluoroquinolone therapy

Emergence of resistance to fluoroquinolones was observed in two clinical isolates of Pseudomonas aeruginosa after ciprofloxacin or norfloxacin monotherapy. In the first case, the resistant variants exhibited quinolone-imipenem cross-resistance (MIC of norfloxacin and ciprofloxacin: 16 mg/L; MIC of imipenem: 8 mg/L), although the patient had never received imipenem treatment, while the strain from the second case remained imipenem-susceptible (MIC of norfloxacin or ciprofloxacin: 8 mg/L; MIC of imipenem: 2 mg/I). The frequency of in-vitro emergence of variants resistant to imipenem and fluoroquinolones was studied for the two strains, with imipenem or fluoroquinolones as selecting agents. Ciprofloxacin and three other quinolones (norfloxacin, temafloxacin and tosufloxacin) selected imipenem-resistant variants in a similar way to imipenem for the first strain, but not for the other. In contrast, imipenem did not select quinolone-resistant variants from either strain. For both strains, killing curves demonstrated that a bactericidal effect could be obtained with a drug combination (2 x MIC of ciprofloxacin and 2 x MIC of imipenem) without any selection of resistant mutants after 24 h, thereby suggesting the possible use of this combined regimen for treating severe P. aeruginosa infection.

Molecular typing of nosocomial strains of Legionella pneumophila by arbitrarily primed PCR

Arbitrarily primed PCR with two different primers was compared with ribotyping and monoclonal antibody analysis for typing Legionella strains. Applied to 11 epidemiologically unrelated strains, arbitrarily primed PCR resulted in an index of discrimination of 100% with both primers. It was found able to identify an epidemic clone of Legionella pneumophila serogroup 1 that was isolated from both patients and a hot water circuit of the same hospital.

Infliximab Does Not Worsen Outcomes During Flare-ups Associated with Cytomegalovirus Infection in Patients with Ulcerative Colitis

BACKGROUND

Immunosuppressive therapies used for treating ulcerative colitis are known to favor chronic and latent viral diseases. This study aimed at evaluating prospectively the association between colonic cytomegalovirus (CMV) reactivation and anti-tumor necrosis factor (TNF) monoclonal antibodies (mabs) by comparison to azathioprine (AZA) in a series of flare-ups occurring in consecutive ulcerative colitis patients.

METHODS

A total of 109 flare-ups were recorded in 73 patients receiving a maintenance therapy by anti-TNF mabs (n = 69) or AZA (n = 40). The CMV DNA load in colonic tissue was determined by reverse transcription polymerase chain reaction on a pair of biopsies.

RESULTS

The number of CMV reactivation was of 35% and 38% in patients receiving anti-TNF mabs and AZA, respectively. The median of CMV DNA load was 378 [10-29,800] and 8300 [10-3,25,000] copies/mg of tissue in patients treated by anti-TNF mabs and AZA, respectively (P = 0.11 by Mann-Whitney U test). In a subgroup of 45 patients under anti-TNF mabs requiring an optimized treatment by infliximab, clinical remission (partial Mayo score <3) was not significantly impacted by the presence of CMV reactivation at the time of flare-up (P = 0.52). Twenty of these patients underwent a second colonic biopsy 8 weeks after the initiation of flare-up therapy; except for 3 patients, the colonic CMV DNA load was stable or decreased.

CONCLUSIONS

Patients under anti-TNF maintenance therapy are not at higher risk of CMV reactivation in case of flare-up. No reciprocal adverse influence was observed between anti-TNF mabs and CMV infection, suggesting that these drugs must be considered for treating flare-ups associated to CMV reactivation.