Prevalence of drug resistance among HIV-1 treatment-naive patients in Greece during 2003-2015: Transmitted drug resistance is due to onward transmissions

BACKGROUND

The prevalence of HIV-1 drug resistance among treatment-naïve patients ranges between 8.3% and 15% in Europe and North America. Previous studies showed that subtypes A and B were the most prevalent in the Greek HIV-1 epidemic. Our aim was to estimate the prevalence of resistance among drug naïve patients in Greece and to investigate the levels of transmission networking among those carrying resistant strains.

METHODS

HIV-1 sequences were determined from 3428 drug naïve HIV-1 patients, in Greece sampled during 01/01/2003-30/6/2015. Transmission clusters were estimated by means of phylogenetic analysis including as references sequences from patients failing antiretroviral treatment in Greece and sequences sampled globally.

RESULTS

The proportion of sequences with SDRMs was 5.98% (n=205). The most prevalent SDRMs were found for NNRTIs (3.76%), followed by N(t)RTIs (2.28%) and PIs (1.02%). The resistance prevalence was 22.2% based on all mutations associated with resistance estimated using the HIVdb resistance interpretation algorithm. Resistance to NNRTIs was the most common (16.9%) followed by PIs (4.9%) and N(t)RTIs (2.8%). The most frequently observed NNRTI resistant mutations were E138A (7.7%), E138Q (4.0%), K103N (2.3%) and V179D (1.3%). The majority of subtype A sequences (89.7%; 245 out of 273) with the dominant NNRTI resistance mutations (E138A, K103N, E138Q, V179D) were found to belong to monophyletic clusters suggesting regional dispersal. For subtype B, 68.1% (139 out of 204) of resistant strains (E138A, K103N, E138Q V179D) belonged to clusters. For N(t)RTI-resistance, evidence for regional dispersal was found for 27.3% and 21.6% of subtype A and B sequences, respectively.

CONCLUSIONS

The TDR rate based on the prevalence of SDRM is lower than the average rate in Europe. However, the prevalence of NNRTI resistance estimated using the HIVdb approach, is high in Greece and it is mostly due to onward transmissions among drug-naïve patients.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Effects of highly active antiretroviral therapy on platelet activating factor metabolism in naive HIV-infected patients: ii) study of the abacavir/lamivudine/efavirenz HAART regimen

Human Immunodeficiency Virus (HIV)-infected patients are at increased risk for cardiovascular diseases partly due to chronic inflammation. Some antiretroviral drugs and Highly Active Anti-Retroviral Therapy (HAART) regimens seem to be related and amplify this increased risk, especially the ones containing abacavir. Platelet-Activating-Factor (PAF) is a potent inflammatory mediator that is implicated in both cardiovascular diseases and HIV-related manifestations. Our objective is to study the in vivo effect of the abacavir/lamivudine/efavirenz first-line HAART regimen on PAF metabolism in HIV-infected patients. The specific activities of PAF basic biosynthetic enzymes in leukocytes and platelets, PAF-cholinephosphotransferase (PAF-CPT) and lyso-PAF-acetyltransferase (Lyso-PAF-AT), but also those of PAF-basic catabolic enzymes, PAF acetylhydrolase (PAF-AH) in leukocytes and platelets and Lipoprotein-associated-Phospholipase-A2 (LpPLA2) in plasma, were measured in blood samples of 10 asymptomatic naïve male HIV-infected patients just before and after 1, 3 and 6 months of treatment. CD4 cell counts, viral load and several biochemical markers were also measured in the same blood samples of these patients. The repeated ANOVA measures and the Pearson r criterion were used for studying statistical differences and correlations - partial correlations respectively. Even though viral load was decreased and CD4 cell counts were beneficially increased after treatment with the abacavir/lamivudine/efavirenz regimen, the main enzyme of the remodelling PAF-synthesis that is implicated in pro-atherogenic inflammatory procedures, Lyso-PAF-AT activity, was increased at 3 months of treatment in both leukocytes and platelets, while the main enzyme of PAF-degradation, PAF-AH, was increased as a response only in leukocytes at the 3rd month. Although the abacavir/lamivudine/efavirenz HAART regimen exhibits very efficient antiretroviral activities, on the other hand it induces an in vivo transient increase in the inflammation-related remodeling PAF-biosynthetic pathway. This finding supports the hypothesis of inflammation-mediated increased cardiovascular risk in HIV-infected patients during the first months of abacavir-containing HAART.

Impaired phagocytosis among patients infected by the human immunodeficiency virus: implication for a role of highly active anti-retroviral therapy

In patients with human immunodeficiency virus (HIV) infection, neutrophil and monocyte functions, including phagocytosis, are impaired. The purpose of this study was to investigate changes of phagocytic function and respiratory burst occurring over the course of patients infected by the HIV-1 virus. Treatment-naive patients (group B), patients receiving highly active anti-retroviral treatment (HAART) (group C) and patients in which HAART has failed (group D) were studied and compared with healthy volunteers (group A). Phagocytosis and oxidative burst were evaluated using commercially available kits. Results clearly denote a significant decrease of the phagocytic function of both cell types of groups B and C compared with group A. Among group C patients, those in the upper quartile of CD4 increase had higher oxidative burst compared with patients of the other quartiles. In addition, comparisons clearly showed a lower degree of phagocytic function and of oxidative burst of both monocytes and neutrophils of group D compared with group B. Finally, it was found that monocyte and neutrophil function was correlated inversely to the change in viral load, i.e. the greater the decrease of viral load, the better the phagocytic and oxidative activity. Innate immunity defects appear to be present in HIV-positive patients, regarding phagocytic activity and oxidative burst of monocytes and neutrophils. These defects are greatly influenced by the level of treatment efficacy, with emphasis on CD4 cell counts and viral load.

HIV-1 outbreak among injecting drug users in Greece, 2011: a preliminary report

A significant increase (more than 10-fold) in the number of newly diagnosed HIV-1 infections among injecting drug users (IDUs) was observed in Greece during the first seven months of 2011. Molecular epidemiology results revealed that a large proportion (96%) of HIV-1 sequences from IDUs sampled in 2011 fall within phylogenetic clusters suggesting high levels of transmission networking. Cases originated from diverse places outside Greece supporting the potential role of immigrant IDUs in the initiation of this outbreak.

Periodontal microflora of HIV infected patients with periodontitis

The aim of this study was to determine the microbial profile of periodontal lesions in HIV seropositive patients and to compare it with rapidly progressing periodontal lesions in systemically healthy patients. The subgingival microflora of 20 CDC II, 20 CDC III, 20 CDC IV/V and 20 systemically healthy patients with rapidly progressing periodontitis was examined. Four sites with greatest probing depth in each patient were selected for microbiological sampling. The samples were cultured aerobically and anaerobically for bacterial isolation using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. The microflora of periodontitis lesions within the three stages of the HIV infection was similar to that of progressing periodontitis in systemically healthy adults including Campylobacter rectus, Capnocytophaga spp., Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Selenomonas spp. and Peptostreptococcus micros. However, HIV seropositive periodontitis lesions harboured a range of exogenous pathogens rarely associated with common types of periodontitis including Staphylococcus aureus, Enterobacter cloaca, Pseudomonas aeruginosa, Candida albicans, Enterococcus faecalis, Enterococcus avium, Clostridium difficile, Aspergillus fumigatus, Klebsiella pneumoniae and Mycoplasma incognitum. The lack of immune effector and regulatory cells in HIV infected patients could in fact explain the increase of some opportunistic pathogens and the characteristic and rapidly progressing nature of the periodontal disease in these patients.

Are Specific Antiretrovirals associated with an Increased Risk of Discontinuation due to Toxicities or Patient/Physician Choice in patients with Hepatitis C Virus Coinfection?

Background

Liver damage associated with hepatitis C (HCV) may influence the likelihood of experiencing discontinuation due to toxicities or patient/physician choice (TOXPC) in patients taking combination antiretroviral therapy (cART). Little information to address this concern is available from clinical trials as patients with HCV are often excluded.

Aims

To compare incidence rates of discontinuation due to TOXPC associated with specific antiretrovial drugs in patients with or without HCV.

Patients/methods

A total of 4929 patients from EuroSIDA under follow-up from January 1999 on a specific nucleoside pair (zidovudine/lamivudine, didanosine/stavudine, stavudine/lamivudine, or other) with a third drug (abacavir, nelfinavir, indinavir, nevirapine, efavirenz, lopinavir/ ritonavir or other boosted-protease inhibitor (PI)-containing regimen) and with known HCV serostatus were studied for the incidence of discontinuation of any nucleoside pair or third drug due to TOXPC. Incidence rate ratios were derived from Poisson regression models.

Results

In total 1358 patients had HCV (27.5%). During 12 799 person-years of follow-up there were 2141 discontinuations due to TOXPC for nucleoside pairs and 2501 for third drugs. The incidence of discontinuation due to TOXPC was consistently higher in patients with HCV after stratification by nucleoside pair or third drug. After adjustment for CD4+ count, gender, exposure group, time on HAART, region and treatment regimen, there were few differences in the rate of discontinuation due to TOXPC in those with HCV compared with those without for any nucleoside pairs or third drugs. Similar results were seen when concentrating on discontinuation due to toxicities alone.

Conclusions

Although patients with HCV generally had higher rates of discontinuation due to TOXPC compared with patients without HCV, there was little evidence to suggest that this was associated with any specific nucleoside pair or third drug used as part of cART. Our results do not suggest that any specific component of cART is more poorly tolerated in patients with HCV or that the presence of HCV should influence the choice between antiretrovirals used as part of a cART regimen.

Thymidine Analogue Mutation Profiles: Factors Associated with Acquiring Specific Profiles and their Impact on the Virological Response to Therapy

Background

Studies have suggested that HIV-1 may develop thymidine analogue mutations (TAMs) by one of two distinct pathways – the TAM1 pathway (including mutations 41L, 210W and 215Y) or the TAM2 pathway (including mutations 67N, 70R and 219E/Q) – under the pressure of a not fully suppressive thymidine-analogue-containing regimen.

Methods

Frozen plasma samples stored in the EuroSIDA repository were selected and sent to two central laboratories for genotypic analysis. We considered 733 patients with at least one genotypic test showing ≥1 TAMs (the first of these tests in chronological order was used). TAM1 and TAM2 genotypic profiles were defined in accordance with previous literature. Statistical modelling involved logistic regression and linear regression analysis for censored data.

Results

The observed frequencies of patterns classifiable as TAM1 or TAM2 profiles were markedly higher than the probabilities of falling into these classifications by chance alone. The chance of detecting a TAM2 profile increased by 25% per additional year of exposure to zidovudine. We found that mutations 67N and 184V were not associated with a particular TAM profile. In the presence of TAM2 profiles, the adjusted mean difference in the 6-month viral reduction was 0.96 log10 copies/ml (95% confidence interval: 0.20; 1.73) higher in patients who started stavudine-containing regimens instead of zidovudine-containing regimens.

Conclusions

This study provides evidence that the suggested TAM clustering is a real phenomenon and that it may be driven by which thymidine analogue the patients has used. In patients with TAM2-resistant viruses, stavudine appears to retain greater viral activity than zidovudine.

Prevalence of resistance-associated mutations in newly diagnosed HIV-1 patients in Greece

The prevalence of HIV-1 drug resistance mutations in naïve patients has been previously shown to differ greatly with the geographic origin. The purpose of this study was to prospectively estimate the prevalence of HIV-1 drug resistance in Greece by analyzing a representative sample of newly HIV-1 diagnosed patients, as part of the SPREAD collaborative study. Protease (PR) and partial reverse transcriptase (RT) sequences were determined from 101 newly diagnosed HIV-1 patients, in Greece, during the period September 2002--August 2003, representing one-third of the total newly diagnosed HIV-1 patients in the same time period. The prevalence of HIV-1 drug resistance was estimated according to the IAS-USA mutation table taking into account all mutations in RT and only major mutations in PR region. The overall prevalence of resistance was 9% [95% confidence interval (CI): 4.2--16.2%]. The prevalence of mutations associated with resistance to NRTIs was 5% (95% CI: 1.6--11.2%), for NNRTIs was 4% (95% CI: 1.1--9.8%), while no major resistance mutations were found in PR. No multi-class resistance was detected in the study population. The prevalence of resistant mutations in the recent seroconverters was 22%. For two individuals, there was clear evidence for transmitted resistance based on epidemiological information for a known source of HIV-1 transmission. The prevalence of the HIV-1 non-B subtypes and recombinants was 52%.

Baseline Resistance and Virological Outcome in Patients with Virological Failure who Start a Regimen Containing Abacavir: Eurosida Study

Objectives

To investigate the ability of several HIV-1 drug-resistance interpretation systems, as well as the number of pre-specified combinations of abacavir-related mutations, to predict virological response to abacavir-containing regimens in antiretroviral therapy-experienced, abacavir-naive patients starting an abacavir-containing regimen in the EuroSIDA cohort.

Patients and methods

A total of 100 HIV-infected patients with viral load (VL) >500 copies/ml who had a plasma sample available at the time of starting abacavir (baseline) were included. Resistance to abacavir was interpreted by using eight different commonly used systems that consisted of rules-based algorithms or tables of mutations. Correlation between baseline abacavir-resistance mutations and month 6 virological response was performed on this population using a multivariable linear regression model accounting for censored data.

Results

The baseline VL was 4.36 log10 RNA copies/ml [interquartile range (IQR): 3.65–4.99 log10 RNA copies/ml] and the median CD4 cell count was 210 cells/μl (IQR: 67–305 cells/μl). Our patients were pre-exposed to a median of seven antiretrovirals (2–12) before starting abacavir therapy. The median (range) number of abacavir mutations (according to the International AIDS Society-USA) detected at baseline was 3.5 (0–8). Overall, the Kaplan–Meier estimate of the median month 6 VL decline was 0.86 log10 RNA copies/ml [95% confidence intervals (95% CI): 0.45–1.24]. The VL in those patients ( n=31) who intensified treatment by adding only abacavir decreased by a median 0.20 log10 RNA copies/ml (95% CI: -0.18; +0.94). The proportion of patients who harboured viruses fully resistant to abacavir among the eight genotypic resistance interpretation algorithms ranged from 12% [Agence Nationale de Recherches sur le SIDA (ANRS)] to 79% [Stanford HIV RT and PR Sequence Database (HIVdb)]. Some interpretation systems showed statistically significant associations between the predicted resistance status and the virological response while others showed no consistent association. The number of active drugs in the regimen was associated with greater virological suppression (additional month 6 VL reduction per additional sensitive drug=0.51, 95% CI: 0.15–0.88, P=0.006); baseline VL was also weakly associated (additional month 6 VL reduction per log10 higher=0.30, 95% CI: -0.02; +0.62, P=0.06). In contrast, the number of drugs previously received was associated with diminished viral reduction (additional month 6 VL reduction per additional drug=-0.14, 95% CI: -0.28; 0.00, P=0.05).

Conclusions

Our results revealed a high degree of variability among several genotypic resistance interpretation algorithms currently in use for abacavir. Therefore, the interpretation of genotypic resistance for predicting response to regimens containing abacavir remains a major challenge.

Antimicrobial-induced endotoxaemia in patients with sepsis in the field of acute pyelonephritis

BACKGROUND

In vitro results have shown that antimicrobial agents may induce the Gram-negative bacteria to release endotoxins (LPS), which in turn, could trigger the secretion of cytokines from monocytes.

AIMS

To compare the effect of cefuroxime, netilmicin or ciprofloxacin on serum levels of LPS and tumour necrosis factor-alpha (TNFalpha).

METHODS

Seventy-four patients with acute pyelonephritis caused by Gram-negative bacteria and signs of sepsis were randomly assigned to receive one of three intravenous regimens of cefuroxime, netilmicin or ciprofloxacin. Blood samples were collected before therapy and at specified time intervals for 96 hours after the initiation of treatment for the determination of serum levels of LPS and of TNFalpha.

RESULTS

Patients treated with cefuroxime presented an early peak of LPS and of TNFalpha in serum two hours after the initiation of treatment compared to the other study groups. After that time interval, concentrations of LPS and TNFalpha were similar in all the study groups. Fever accompanied by endotoxaemia was still detected for 48 hours after the start of therapy in 36, 37.5 and 36% of patients treated with cefuroxime, netilmicin and ciprofloxacin respectively. The corresponding figures for these agents at 72 hours were 28, 12.5 and 24%, respective and 12, 4.2 and 4% at 96 hours (P value not significant).

CONCLUSIONS

With the exception of an early peak in the serum levels of LPS and TNFalpha in patients treated with cefuroxime, no significant difference could be detected amongst the study groups as far as their effect on serum levels of LPS and TNFalpha were concerned. This suggests that these three antimicrobial agents may be administered safely at the early stages of sepsis.

Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

Low-dose IFN-alpha monotherapy in treatment-naive individuals with HIV-1 infection: evidence of potent suppression of viral replication

To evaluate the safety and antiviral action of interferon-alpha (IFN-alpha) in HIV-1 infection, we undertook a proof of concept study in 27 treatment-naive patients. Eligible patients comprised two groups: the IFN-alphaT group (n = 17), which received 5 MIU IFN-alpha s.c. daily for 32 consecutive days, and the IFN-alphaNT group (n = 10), which did not receive IFN-alpha prior to highly active antiretroviral therapy (HAART), which was commenced on day 28 in both groups. IFN-alphaTreatment was well tolerated in 14 of the 17 patients of the IFN-alphaT group who completed the study. The mean HIV RNA reduction in the IFN-alphaT group on day 14 was 1.1 log(10). Viral load suppression was inversely associated with baseline viral load (p = 0.031). Four weeks after initiation of HAART, IFN-alphaT and IFN-alphaNT group patients had 2.40 and 1.82 log(10) HIV RNA reduction from baseline, respectively (p < 0.001). There was no evidence of cross-resistance with existing antiretrovirals in patients with HIV-RNA rebound after initial plasma viral load decline > or = 1 log(10) during IFN-alpha monotherapy. Thus, low daily IFN-alpha exhibits potent anti-HIV-1 activity in vivo without serious adverse effects. These properties render IFN-alpha an attractive candidate for further assessment as a constituent of HAART.

Virological and immunological response to HAART therapy in a community-based cohort of HIV-1-positive individuals

PURPOSE

To determine virological and immunological response to highly active antiretroviral therapy (HAART) and to investigate factors influencing response in a community-based setting.

METHOD

Plasma HIV RNA levels and CD4 cell counts were studied in 168 unselected individuals starting HAART including indinavir or ritonavir or hard-gel saquinavir-containing regimens.

RESULTS

Overall, 60% of the patients reduced their HIV RNA to below 500 Eq/mL, but half of them experienced a subsequent virologic rebound. Patients with higher baseline HIV RNA, higher baseline CD4 cell count, and simultaneous initiation of combination therapy and patients on indinavir or ritonavir regimen were more likely to have virologic response within 6 months since HAART initiation. Patients with lower baseline CD4 cell count and with lower rates of viral clearance had a higher probability of a subsequent virologic rebound. Forty percent of the patients had increased their CD4 cell counts by more than 100 cells/microL (immunologic response). The probability of immunologic response was independent of baseline HIV RNA levels and CD4 cell count; however, the more complete the virologic suppression, the higher the probability of immunologic response. Thirty percent of the patients had discordance between virologic and immunologic responses.

CONCLUSION

The rate of virologic failure in this unselected group of patients was higher than that observed in randomized clinical trials, but only a minority (11%) of the patients were treatment naïve. Starting combination therapy simultaneously and initiating antiretroviral therapy before advanced HIV disease has developed predict virologic response, whereas the magnitude of viral suppression predicts mid to long immunological response.

Comparative evaluation of the QUANTIPLEX HIV-1 RNA 2.0 and 3.0 (bDNA) assays and the AMPLICOR HIV-1 MONITOR v1.5 test for the quantitation of human immunodeficiency virus type 1 RNA in plasma

HIV-1 RNA measurements from 84 plasma specimens obtained with the QUANTIPLEX HIV-1 RNA 2.0 and 3.0 (bDNA) assays (Chiron Diagnostics, Emeryville, CA) and with the AMPLICOR HIV-1 MONITOR Test, version 1.5 with ultra-sensitive specimen preparation (Roche Diagnostic Systems, Inc., Branchburg, NJ) were compared. The absolute RNA values of tested specimens differed significantly between bDNA 2.0 and bDNA 3.0 or Monitor v1.5 measurements (Wilcoxon signed-rank test P<0.001). Results generated with bDNA 3.0 or with Monitor v1.5 were approximately twofold greater than those generated with bDNA 2.0, with smaller differences at higher HIV-1 RNA levels and greater differences at RNA levels below 1000 copies per ml. Although highly correlated (r=0.92 and 0.86, respectively), viral load data generated with bDNA 2.0 and either bDNA 3.0 or Monitor v1.5 were in poor agreement. Concordant results (difference in log(10) copies per ml <0.5) were found at frequencies of 80% for bDNA 2.0 and bDNA 3.0 and only at 58.5% for bDNA 2.0 and Monitor v1.5. In contrast, bDNA 3.0 and Monitor v1.5 measurements were highly correlated (r=0.96) and in good agreement (92.7%).

Changing patterns of mortality across Europe in patients infected with HIV-1. EuroSIDA Study Group

BACKGROUND

The introduction of combination antiretroviral therapy and protease inhibitors has led to reports of falling mortality rates among people infected with HIV-1. We examined the change in these mortality rates of HIV-1-infected patients across Europe during 1994-98, and assessed the extent to which changes can be explained by the use of new therapeutic regimens.

METHODS

We analysed data from EuroSIDA, which is a prospective, observational, European, multicentre cohort of 4270 HIV-1-infected patients. We compared death rates in each 6 month period from September, 1994, to March, 1998.

FINDINGS

By March, 1998, 1215 patients had died. The mortality rate from March to September, 1995, was 23.3 deaths per 100 person-years of follow-up (95% CI 20.6-26.0), and fell to 4.1 per 100 person-years of follow-up (2.3-5.9) between September, 1997, and March, 1998. From March to September, 1997, the death rate was 65.4 per 100 person-years of follow-up for those on no treatment, 7.5 per 100 person-years of follow-up for patients on dual therapy, and 3.4 per 100 person-years of follow-up for patients on triple-combination therapy. Compared with patients who were followed up from September, 1994, to March, 1995, patients seen between September, 1997, and March, 1998, had a relative hazard of death of 0.16 (0.08-0.32), which rose to 0.90 (0.50-1.64) after adjustment for treatment.

INTERPRETATION

Death rates across Europe among patients infected with HIV-1 have been falling since September, 1995, and at the beginning of 1998 were less than a fifth of their previous level. A large proportion of the reduction in mortality could be explained by new treatments or combinations of treatments.

Downregulation of CD28 surface antigen on CD4+ and CD8+ T lymphocytes during HIV-1 infection

A progressive significant decrease of CD28 surface antigen expression on CD4+ (mean, 90, 86, 79, 68% in stages I, II, III, and IV, respectively, versus 96% in normals), as well as on CD8+ T lymphocytes (mean, 38, 32, 31, and 29% in stages I, II, III, and IV, respectively, versus 47% in normals) was observed during HIV-1 infection. The increase of cytotoxic/suppressor T cells, in both percentage and absolute numbers, that was observed in almost all HIV-1 patients, was associated with an increase of the CD8+ cells lacking the CD28 surface antigen. The loss of CD28 antigen expression was parallel to the increase of CD38, human leukocyte antigen (HLA)-DR, and CD45RO antigen expression on T lymphocytes throughout the disease. Furthermore, a positive significant correlation within the CD4+ but not the CD8+ subset was observed between the percentage of cells lacking the CD28 antigen and the percentage of cells expressing the HLA-DR and CD38 antigens, a finding suggesting that the loss of CD28 antigen expression on CD4+ lymphocytes may be associated with T-lymphocyte activation. Patients treated with zidovudine showed no significant differences in the percentages of either CD4+CD28+ or CD8+CD28+ T-cell subsets when compared to untreated patients. These phenotypic changes may be associated with the functional defects of T lymphocytes in HIV-1 infected individuals.

Asymptomatic bacteriuria of pregnancy: do obstetricians bother?

In view of the potentially serious consequences of asymptomatic bacteriuria of pregnancy (ASB), we surveyed the attitudes of Greek obstetricians towards this entity. A total of 108 obstetricians practicing in the area of Athens completed a questionnaire concerning ASB. Only 73 of the 108 stated that they screen their clients for ASB (51 of them when pyuria is present and only 22 in all pregnant women). Of special interest is the finding that a larger percentage of younger obstetricians (practicing for up to 9 years) habitually screen their patients, compared to older ones (83% vs 60%). Concerning treatment of ASB, only 45 out of 73 doctors screening for ASB give any treatment when ASB is present. Most obstetricians (87%) prefer a beta-lactam antibiotic. In almost all cases 7-10 days are considered the appropriate duration of treatment. Better education of obstetricians, especially the older ones, concerning detection and management of ASB is needed.

Activity of cefpirome (HR810) against Pseudomonas aeruginosa strains with characterised resistance mechanisms to beta-lactam antibiotics

The activities of cefpirome, cefotaxime, ceftazidime and ceftriaxone were compared against laboratory and clinical strains of Pseudomonas aeruginosa. Isolates with well characterised resistance mechanisms were included. Against carbenicillin-susceptible isolates cefpirome was more active than cefotaxime and ceftriaxone, but less active than ceftazidime. The activity of all four cephalosporins was impaired against isolates that had increased intrinsic (i.e. non-beta-lactamase-mediated) carbenicillin resistance. However, cefpirome and ceftazidime, unlike the other compounds, remained active at less than 16 mg/l against such strains, whereas cefotaxime and ceftriaxone largely failed to do so. Cefpirome maintained full activity against most isolates with plasmid-mediated beta-lactamases, as did the other cephalosporins. Transconjugant studies indicated that only LCR-1 and PSE-2 enzymes could protect P. aeruginosa against cefpirome. Isolates with partial or total chromosomal beta-lactamase derepression were highly resistant to cefotaxime and ceftriaxone (MIC greater than 128 mg/l) but only those with total derepression were resistant (MIC 16-32 mg/l) to cefpirome and ceftazidime, while those with partial derepression were sensitive to 4-8 mg/l of the latter antibiotics. Comparison of cefpirome MICs for totally-derepressed P. aeruginosa and their enzyme-deficient mutants indicated that chromosomal beta-lactamase gave less protection against cefpirome than against other cephalosporins tested. Cefpirome was a weak inducer of class I beta-lactamases. Overall, therefore, cefpirome behaved similarly to ceftazidime against the different P. aeruginosa resistance types.

Fleroxacin in single dose oral therapy of uncomplicated lower urinary tract infection

A randomized comparative study was performed in twenty women with acute uncomplicated lower urinary tract infection (UTI). They received a single oral dose of either fleroxacin 600 mg or amoxycillin 3 g. Pathogens were Escherichia coli (17), Proteus mirabilis (2) and Staphylococcus aureus (1). A complete clinical and microbiological cure was observed in all patients of both groups. One patient in the fleroxacin group had gastric irritation. A single oral dose of fleroxacin may be suitable for the treatment of lower UTI even when it is due to organisms resistant to amoxycillin and other traditional oral antimicrobials.

Staphylococcal infections in hospital: the Greek experience

Resistance rates of various species to many antimicrobials are very high in Greece. Mean resistance rates of Staphylococcus aureus isolated in 12 Athens hospitals in the second half of 1986 were 80% for penicillin, 32% for methicillin, 22% for gentamicin, 27% for erythromycin, 17% for lincomycin and 16% for co-trimoxazole. In a prospective study in the General Hospital of Athens from May to July 1987, 40 coagulase-positive staphylococcal strains were isolated from various materials from inpatients. Of these 78% were resistant to penicillin, 50% to methicillin at 37 degrees C, 62% to methicillin at 30 degrees C, 38% to erythromycin, 32% to tobramycin, 15% to clindamycin, 15% to fusidic acid, 9% to amikacin, 5% to netilmicin and 0% to vancomycin. Ten of these strains (seven methicillin-resistant) were responsible for severe infections and three of the affected patients died (two nosocomial pneumonias, one infected burn, all due to methicillin-resistant strains). Another 11 strains (eight methicillin-resistant) were responsible for mild infections. From 41 coagulase-negative staphylococci isolated from inpatients, seven (five methicillin-resistant) were held responsible for mild infections. Of the 20 patients with infections due to methicillin-resistant strains, nine had previously received a beta- lactam antibiotic. Staphylococci are not responsible, however, for a large proportion of infections in our hospital at the moment. High resistance rates in Greece are due to overuse of antibiotics, a phenomenon attributed to a consumer's society behaviour of doctors and patients.

Trimethoprim in enteric fever

Seventy-one patients suffering from typhoid or paratyphoid fever were treated with trimethoprim. Sixty-three were cured. Only three patients continued to excrete Salmonella typhi in stools at the time of discharge from hospital. Trimethoprim alone is a suitable agent for the treatment of enteric fever.