Seven Years of Culture Collection of Neisseria gonorrhoeae: Antimicrobial Resistance and Molecular Epidemiology.

The emergence of Neisseria gonorrhoeae isolates displaying resistance to antimicrobials, in particular to ceftriaxone monotherapy or ceftriaxone plus azithromycin, represents a global public health concern. This study aimed to analyze the trend of antimicrobial resistance in a 7-year isolate collection retrospective analysis in Italy. Molecular typing on a subsample of gonococci was also included. A total of 1,810 culture-positive gonorrhea cases, collected from 2013 to 2019, were investigated by antimicrobial susceptibility, using gradient diffusion method, and by the N. gonorrhoeae multiantigen sequence typing (NG-MAST). The majority of infections occurred among men with urogenital infections and 57.9% of male patients were men who have sex with men. Overall, the cefixime resistance remained stable during the time. An increase of azithromycin resistance was observed until 2018 (26.5%) with a slight decrease in the last year. In 2019, gonococci showing azithromycin minimum inhibitory concentration above the EUCAST epidemiological cutoff value (ECOFF) accounted for 9.9%. Ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae (PPNG) percentages increased reaching 79.1% and 18.7% in 2019, respectively. The most common sequence types identified were 5,441, 1,407, 6,360, and 5,624. The predominant genogroup (G) was the 1,407; moreover, a new genogroup G13070 was also detected. A variation in the antimicrobial resistance rates and high genetic variability were observed in this study. The main phenotypic and genotypic characteristics of N. gonorrhoeae isolates were described to monitor the spread of drug-resistant gonorrhea.

The Limitation of Accessing Hospital Services Due to COVID-19 Pandemic: A Pilot Study of the Telephone Triage to Re-Organize the Access to a Center for Sexual Health in Northwest Italy.

BACKGROUND: The COVID-19 pandemic-related health crisis has imposed measures aimed at reducing the overcrowding of health facilities, by developing telemedicine and by forcing many sexually transmitted infection (STI) clinics to book appointments by telephone. In this work, we evaluate the performance of the nursing telephone triage system, introduced in the major STI center in Northwest Italy, for the adequacy of clinical pathways for of symptomatic STI patients. METHODS: From January to March 2021, all symptomatic patients wishing to access the CeMuSS center first underwent nurse-led telephone triage. Symptoms suggestive of STIs were further classified into four syndromic presentations: cutaneous neoformations, genital and oral ulcers, anogenital discharge, and finally other dermatological manifestations. All other clinical pictures were properly managed and eventually referred to other centers and not considered in the analysis. During the following medical examinations, the concordance between presumptive syndromic diagnosis and confirmed clinical diagnosis were recorded. Cohen k test was used to assess concordance. RESULTS: According to the Cohen k test, a good concordance between telephone presumptive diagnoses and medical clinical assessment was found (73.79% with a k = 0.611), whereas only a scarcely acceptable concordance between expected and real waiting time was established (75.51%, k = 0.34). CONCLUSIONS: Concordance between nursing syndromic diagnosis and syndromic medically confirmed diagnosis is good from a clinical point of view but there is a limitation when considering a public health perspective. An optimal training of nurses may improve the method of telephone triage. For future ongoing emergencies, the implementation of telemedicine with accurate patient management systems is mandatory.

Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar.

In spite of its immutable susceptibility to penicillin, Treponema pallidum (T. pallidum) subsp. pallidum continues to cause millions of cases of syphilis each year worldwide, resulting in significant morbidity and mortality and underscoring the urgency of developing an effective vaccine to curtail the spread of the infection. Several technical challenges, including absence of an in vitro culture system until very recently, have hampered efforts to catalog the diversity of strains collected worldwide. Here, we provide near-complete genomes from 196 T. pallidum strains-including 191 T. pallidum subsp. pallidum-sequenced directly from patient samples collected from 8 countries and 6 continents. Maximum likelihood phylogeny revealed that samples from most sites were predominantly SS14 clade. However, 99% (84/85) of the samples from Madagascar formed two of the five distinct Nichols subclades. Although recombination was uncommon in the evolution of modern circulating strains, we found multiple putative recombination events between T. pallidum subsp. pallidum and subsp. endemicum, shaping the genomes of several subclades. Temporal analysis dated the most recent common ancestor of Nichols and SS14 clades to 1717 (95% HPD: 1543-1869), in agreement with other recent studies. Rates of SNP accumulation varied significantly among subclades, particularly among different Nichols subclades, and was associated in the Nichols A subclade with a C394F substitution in TP0380, a ERCC3-like DNA repair helicase. Our data highlight the role played by variation in genes encoding putative surface-exposed outer membrane proteins in defining separate lineages, and provide a critical resource for the design of broadly protective syphilis vaccines targeting surface antigens.

Low Tenofovir Plasma Exposure in HIV Oral Pre-exposure Prophylaxis Recipients with Gastrointestinal Disorders.

Four pre-exposure prophylaxis (PrEP) users with gastro-intestinal disorders (sleeve gastrectomy, terminal ileitis, celiac disease or chronic diarrhea) and receiving oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) were included. Despite a self-reported high adherence, trough plasma tenofovir concentrations (after a supervised intake) were significantly lower than those observed in PrEP recipients without gastrointestinal disorders [21 (±9.1) vs. 138 (±85) ng/mL]. PrEP users with gastrointestinal disorders may need increased TDF doses or alternative prophylactic measures.

Estimation of Full-Length TprK Diversity in Treponema pallidum subsp. pallidum.

Immune evasion and disease progression of Treponema pallidum subsp. pallidum are associated with sequence diversity in the hypervariable outer membrane protein TprK. Previous attempts to study variation within TprK have sequenced at depths insufficient to fully appreciate the hypervariable nature of the protein, failed to establish linkage between the protein's seven variable regions, or were conducted on isolates passed through rabbits. As a consequence, a complete profile of tprK during infection in the human host is still lacking. Furthermore, prior studies examining how T. pallidum subsp. pallidum uses its repertoire of genomic donor sites to generate diversity within the variable regions of the tprK have yielded a partial understanding of this process due to the limited number of tprK alleles examined. In this study, we used short- and long-read deep sequencing to directly characterize full-length tprK alleles from T. pallidum subsp. pallidum collected from early lesions of patients attending two sexually transmitted infection clinics in Italy. We demonstrate that strains collected from cases of secondary syphilis contain significantly more unique variable region sequences and full-length TprK sequences than those from cases of primary syphilis. Our data, combined with recent data available on Chinese T. pallidum subsp. pallidum specimens, show the near-complete absence of overlap in TprK sequences among the 41 specimens profiled to date. We further estimate that the potential antigenic variability carried by TprK rivals that of current estimates of the human adaptive immune system. These data underscore the immunoevasive ability of TprK that allows T. pallidum subsp. pallidum to establish lifelong infection.IMPORTANCE Syphilis continues to be a significant public health issue in both low- and high-income countries, including the United States where the rate of syphilis infection has increased over the past 5 years. Treponema pallidum subsp. pallidum, the causative agent of syphilis, carries the outer membrane protein TprK that undergoes segmental gene conversion to constantly create new sequences. We performed full-length deep sequencing of TprK to examine TprK diversity in clinical T. pallidum subsp. pallidum strains. We then combined our results with data from all samples for which TprK deep sequencing results were available. We found almost no overlap in TprK sequences between different patients. Moreover, our data allowed us to estimate the total number of TprK variants that T. pallidum subsp. pallidum can potentially generate. Our results support how the T. pallidum subsp. pallidum TprK antigenic variation system is an equal adversary of the human immune system leading to pathogen persistence in the host.

Recurrent herpes labialis and Herpes simplex virus-1 genitalis: what is the link?

BACKGROUND: Recently, Herpes simplex virus (HSV)-1 seroprevalence declined among adolescents, rendering young people lacking HSV-1 antibodies more susceptible to genital HSV-1 acquisition, if sexually exposed. The aim of the present study was to identify the possible risk factors for the development of HSV-1 related Herpes genitalis (HG). METHODS: From January 2012 to December 2015, patients with HG attending three Sexually Transmitted Infections Units in Northern Italy were recruited. A genital swab on the lesions for the search of HSV-1/2 DNA through real time polymerase chain reaction (PCR) and a serum sample for HSV-1/2 specific serology were performed. Moreover, patients were asked whether they had personal history of herpes labialis (HL). Patients with PCR proved HSV-1 HG were included as cases; asymptomatic subjects attending STI Units for a blood check were recruited as controls and were checked for HSV-1/2 serology. RESULTS: The study included 141 cases and 70 controls. Specific HSV-1 antibodies were found in 34.7% of the cases and 67% of the controls. History of recurrent herpes labialis (RHL) was found in 4% of the cases and 31% of the controls. The occurrence of RHL in HSV-1 seropositive patients resulted lower in the case group compared to the control group. CONCLUSIONS: We can speculate about a protective role for RHL against the clinical appearance of HSV-1 HG. The clinical usefulness of our study involved especially the counselling in serodiscordant couples. The presence of HSV-1 antibodies in asymptomatic sexual partners does appear protective for HG manifestation only in presence of RHL history.

Enhanced Molecular Typing of Treponema pallidum subspecies pallidum Strains From 4 Italian Hospitals Shows Geographical Differences in Strain Type Heterogeneity, Widespread Resistance to Macrolides, and Lack of Mutations Associated With Doxycycline Resistance.

BACKGROUND: Although syphilis rates have been relatively high in Italy for more than 15 years, no data on the molecular types of Treponema pallidum subspecies pallidum circulating in this country are yet available. Likewise, no data on how widespread is resistance to macrolide or tetracycline antibiotics in these strains exist. Such data would, however, promote comprehensive studies on the molecular epidemiology of syphilis infections in Italy and inform future interventions aiming at syphilis control in this and other European countries. GOALS AND STUDY DESIGN: Swabs from oral, genital, cutaneous, or anal lesions were obtained from 60 syphilis patients attending dermatology clinics in Milan, Turin, Genoa, and Bologna. Molecular typing of T. pallidum DNA was performed to provide a snapshot of the genetic diversity of strains circulating in Northern Italy. Samples were also screened for mutations conferring resistance to macrolides and tetracyclines. RESULTS: T. pallidum DNA was detected in 88.3% (53/60) of the specimens analyzed. Complete and partial T. pallidum typing data were obtained for 77.3% (41/53) and 15.0% (8/53) of samples, respectively, whereas 4 samples could not be typed despite T. pallidum DNA being detected. The highest strain type heterogeneity was seen in samples from Bologna and Milan, followed by Genoa. Minimal diversity was detected in samples from Turin, despite the highest number of typeable samples collected there. Resistance to macrolides was detected in 94.3% (50/53) of the strains, but no known mutations associated with tetracycline resistance were found. CONCLUSIONS: Genetic diversity among T. pallidum strains circulating in Northern Italy varies significantly among geographical areas regardless of physical distance. Resistance to macrolides is widespread.

Current treatments for anal condylomata acuminata.

INTRODUCTION: Condylomata acuminata are the most common sexually transmitted disease worldwide. They are not usually a serious problem, but it causes emotional distress to patient and physician alike because of its marked tendency to recurrence. The presence of anogenital warts mandates treatment, also for potential degeneration of the lesions. EVIDENCE ACQUISITION: A review of the literature has been performed to analyze proposed treatments for anogenital warts. EVIDENCE SYNTHESIS: Many treatments have been employed. They include cytotoxic agents, immunomodulation and physical ablation. The choice of the appropriate treatment varies depending on the number, size, and location of warts. Complications of various treatments are rare but include permanent depigmentation, itching, pain, scarring, bleeding, anal stenosis or incontinence and sepsis. The therapy of these lesions can sometimes be very painful and expensive, and therapy should not be worse than the disease. CONCLUSIONS: No specific antiviral treatment is currently available, and no consensus has been reached on the appropriate treatment for anogenital warts. No data are available to indicate whether treatment eliminates infectivity, the primary aim of treatment being to remove the lesions. There is a paucity of published randomized trials. Despite the introduction of antiviral treatments such as interferon, immunomodulating agents or imiquimod, surgical destruction or removal remains the treatment of choice.

Time trend analysis (2009-2016) of antimicrobial susceptibility in Neisseria gonorrhoeae isolated in Italy following the introduction of the combined antimicrobial therapy.

INTRODUCTION: Neisseria gonorrhoeae (NG) antimicrobial susceptibility trends to azithromycin, cefixime and ceftriaxone were analyzed, from 2009 to 2016, to monitor changing antimicrobial susceptibility concomitant with the change in prescribing practice in 2012 from cefixime, or ceftriaxone, to ceftriaxone plus azithromycin. Patient characteristics predictive to be infected by antibiotic resistant N. gonorrhoeae were estimated. Finally, the protocol for the treatment of gonorrhoea, in comparison with the international guidelines, was also evaluated. MATERIALS AND METHODS: Data on NG antimicrobial resistance were obtained from a network of sexually transmitted diseases clinics and other laboratories in 12 cities in Italy. We tested the 1,433 gonococci for antimicrobial susceptibility to azithromycin, cefixime and ceftriaxone using a gradient diffusion method. Logistic-regression methods with cluster robust standard errors were used to investigate the association of resistance categories with demographic and clinical patient characteristics and to assess changes in prescribing practices. To minimize bias due to missing data, all statistical models were fitted to data with forty rounds of multiple imputation, using chained equations. RESULTS: The percentage of isolates resistant to cefixime was 17.10% in 2009 and declined up to 1.39% in 2016; at the same time, those resistant to azithromycin was 23.68% in 2009 and 3.00% in 2012. Starting from 2013, azithromycin resistant gonococci tended to increase up to 7.44% in 2016. No ceftriaxone resistant isolates were observed. By multivariate analysis, the men who have sex with women (MSW) and women had a proportional adjusted OR of resistance of 1.25 (95%CI: 0.90; 1.73) and 1.67 (95%CI: 1.16; 2.40), respectively, in comparison with men who have sex with men (MSM). An aOR of resistance of 0.48 (95%CI: 0.21; 1.12) among NG isolated in the pharynx, compared with those isolated in genital sites, was calculated. The proportional aOR of resistance was 0.58 (95%CI: 0.38; 0.89) for presence vs absence of co-infection and 2.00 (95%CI: 1.36; 2.96) for past history vs no history of gonorrhoea.Finally, at least for the period 2013-2016, the older, subjects with anorectal or pharyngeal gonorrhoea infection, subjects with a co-infection, subjects with a previous gonorrhoea infection were not always correctly treated. CONCLUSIONS: Overall, our findings suggest the shifts in N. gonorrhoeae susceptibility to cefixime and azithromycin in the time frame period. First of all, the increasing rate of azithromycin resistance in 2015-2016 in NG isolated in the country need to be monitor in the future. Finally, extensive information on treatment regimens may be useful to asses treatment adherence particularly for the older subjects, subjects with an anorectal or pharyngeal infection, subjects with a co-infection and subjects with a previous history of gonorrhoea. Gonorrhoea treatment strategy should be based on the evidence obtained by the local antimicrobial surveillance system and data about treatment failures.

Molecular characterization of Neisseria gonorrhoeae on non-cultured specimens from multiple anatomic sites.

INTRODUCTION: The aim of this study was to molecularly characterize Neisseria gonorrhoeae on non-cultured specimens collected from multiple anatomic sites. N. gonorrhoeae multiantigen sequence typing (NG-MAST) together with the gene sequence analysis of antimicrobial resistance (AMR) target genes were used. MATERIALS AND METHODS: Seventeen genital and extra-genital samples from eight patients (7 were men who have sex with men, MSM, and 1 women who have sex with men, WSM) with gonorrhoea symptoms were analyzed. For 7, of the 8 patients, conventional culture method has been used to identify gonorrhoea. All the samples were tested with the rapid molecular method CEPHEID. Amplification and sequencing of porB and tbpB, to identify the Sequence Type (ST) by NG-MAST, and penA, mtrR, porB1b, ponA genes were also performed. Antimicrobial susceptibility by Etest, for the available culture positive samples, was carried out. RESULTS: For 7 patients the ST was obtained and for 6 the complete sequence analysis of the AMR target genes was also defined. For the majority of them, samples collected from multiple sites (oropharynx, rectum, vaginal and urethra) confirm the presence of the same gonorrhoea strain. In particular, for 5 patients the same STs and changes in the AMR target genes were identified. CONCLUSION: Molecular characterization on non-cultured or culture negative specimens for gonorrhoea can successfully be applied directly to genital and extra-genital samples. Thus permit to identify the presence of the same strain in patients with gonorrhoea infection in multiple anatomic sites and to predict the antimicrobial susceptibility pattern.

Louseborne Relapsing Fever among East African Refugees, Italy, 2015.

During June 9-September 30, 2015, five cases of louseborne relapsing fever were identified in Turin, Italy. All 5 cases were in young refugees from Somalia, 2 of whom had lived in Italy since 2011. Our report seems to confirm the possibility of local transmission of louse-borne relapsing fever.

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identification and clustering of Neisseria gonorrhoeae.

BACKGROUND: The sexually transmitted infection gonorrhea remains a public health concern for becoming resistant to drug treatments available. The purpose of this study was to evaluate the usefulness of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to identify and cluster Neisseria gonorrhoeae. From a current monitoring in Italy, as part of the European Gonococcal Antimicrobial Surveillance Programme (EURO-GASP), 93 gonococci collected from 2007 to 2012 susceptible (44 isolates) and resistant (49 isolates) to cefixime were selected. Minimum Inhibitory Concentration (MIC) values for cefixime was assessed by Etest carried out in agreement with the manufacturer's instructions and interpreted referring to European Committee on Antimicrobial Susceptibility testing (EUCAST) clinical breakpoints criteria. Data obtained by N. gonorrhoeae multiantigen sequence typing (NG-MAST) and the dendrogram based on the concatenation of porB and tbpB genes were evaluated. MALDI-TOF MS, to reconfirm gonorrhea identification, analyzed single colonies from freshly grown isolates and applied directly on a ground-steel MALDI target plate. For the MALDI-TOF dendrogram cluster analysis, MSPs (Main Spectrum Profile) from each isolate were created acquiring 5000 shots from 10 technical replicates obtained from bacteria extraction. RESULTS: Molecular typing by NG-MAST showed 28 sequence types (STs); G1407 was the predominant accounting for 75 gonococci. All the 93 gonococci, except one, were correctly identified at species level by MALDI-TOF MS and G1407 isolates were divided into two clusters. CONCLUSION: MALDI-TOF MS for a real-time detection and cluster analysis of gonorrhea is a promising tool for surveillance purposes. Moreover, additional studies are required to collect more data on the performance of MALDI-TOF MS for gonococci.

Changing antimicrobial resistance profiles among Neisseria gonorrhoeae isolates in Italy, 2003 to 2012.

The emergence of Neisseria gonorrhoeae isolates displaying resistance to antimicrobial agents is a major public health concern and a serious issue related to the occurrence of further untreatable gonorrhea infections. A retrospective analysis on 1,430 N. gonorrhoeae isolates, collected from 2003 through 2012, for antimicrobial susceptibility by Etest and molecular characterization by Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) was carried out in Italy. Azithromycin-resistant gonococci decreased from 14% in 2007 to 2.2% in 2012. Similarly, isolates with high MICs to cefixime (>0.125 mg/liter) decreased from 11% in 2008 to 3.3% in 2012. The ciprofloxacin resistance rate remains quite stable, following an increasing trend up to 64% in 2012. The percentage of penicillinase-producing N. gonorrhoeae (PPNG) significantly declined from 77% in 2003 to 7% in 2012. A total of 81 multidrug-resistant (MDR) gonococci were identified, showing 11 different antimicrobial resistance patterns. These were isolated from men who have sex with men (MSM) and from heterosexual patients. Two sequence types (STs), ST661 and ST1407, were the most common. Genogroup 1407, which included cefixime-, ciprofloxacin-, and azithromycin-resistant isolates, was found. In conclusion, a change in the antimicrobial resistance profiles among gonococci was identified in Italy together with a percentage of MDR isolates.

Update on antimicrobial susceptibility and genotype of Neisseria gonorrhoeae isolated in Italy.

Antimicrobial susceptibilities and genotypes of Neisseria gonorrhoeae collected in 2006-2010 from 6 medical centers located in Italy were compared with those from a previous survey conducted in 2003-2005. Resistance to ciprofloxacin increased from 34.2% to 62% whereas penicillin resistance declined from 25.5% to 14%. Important change in antimicrobial resistance rates and a high genetic variability among N. gonorrhoeae from Italy were observed.

Sexual behaviour reported by a sample of Italian MSM before and after HIV diagnosis.

In 2006 we conducted a cross-sectional study involving hospital clinical centres in five Italian cities to compare the sexual behaviour of HIV-positive MSM (men who have sex with men) before and after the diagnosis of HIV infection. Each centre was asked to enrol 30 HIV-positive persons aged ≥ 18 years. The questionnaire was administered to 143 MSM on average 9 years after HIV diagnosis. After diagnosis there was a decrease in the number of sexual partners: the percentage of persons who reported having had more than 2 partners decreased from 95.8% before diagnosis to 76.2% after diagnosis. After diagnosis, there was a significant decrease in the percentage of persons who had never (or not always) used a condom with their stable partner for anal sex from 69.2% before diagnosis to 26.6% after diagnosis and for oral-genital sex from 74.8% before diagnosis to 51.7% after diagnosis. Though at-risk behaviour seems to decrease after diagnosis, seropositive MSM continue to engage in at-risk practices: one fourth of them did not use a condom during sexually transmitted infections (STI) episodes, 12.5% of the participants had had sex for money, and 8.4% had paid for sex. The study shows that our sample of Italian HIV-positive MSM, though aware of being infected, engage in sexual behaviours that could sustain transmission of HIV and other STIs. The results could constitute the first step in implementing national prevention programs for persons living with HIV.

Circulating levels of interleukin-17A and interleukin-23 are increased in patients with gonococcal infection.

Neisseria gonorrhoeae is the etiological agent of gonorrhoea, an infectious disease characterized by acute inflammation of the urogenital tract with a massive infiltration of neutrophils. Polymorphonuclear leukocyte recruitment is one of the activities of the recently described interleukin-17A (IL-17A); thus, we analyzed the serum concentration of IL-17A, together with IL-23 and interferon-γ (IFN-γ), in 27 patients with gonorrhoea. The concentration of these cytokines in patients' sera was significantly higher than that detected in healthy controls and an inverse correlation was found between the concentrations of IL-17A and IFN-γ. This is the first report showing a significant increase of IL-17A and IL-23 serum levels in patients with gonorrhoea, suggesting new players in the immune response to N. gonorrhoeae.

Trend of ciprofloxacin resistance in Neisseria gonorrhoeae strains isolated in Italy and analysis of the molecular determinants.

A total of 599 Neisseria gonorrhoeae strains collected in Italy in 2 periods, 2003 to 2005 and 2007 to 2008, were screened for ciprofloxacin susceptibility by Etest. Ciprofloxacin-resistant strains (49.7%) were characterized by i) serovar determination, patterns of mutation in gyrA, and parC genes (38%, randomly selected) and ii) N. gonorrhoeae multiantigen sequence typing (56% of the strains isolated from patients who declared their sexual orientation). The percentage of ciprofloxacin-resistant strains increased from 42 (2003-2005) to 58 (2007-2008); in the second period, strains with MIC value >32 microg/mL have been observed. Mutations in gyrA and parC genes were identified in the majority of strains (88%). Ciprofloxacin-resistant isolates among men who have sex with men (MSM) increased from 24% in 2003 to 2005 to 47% in 2007 to 2008. However, sequence types exclusively found among MSM were mostly due to a single strain. This is the first study in Italy combining N. gonorrhoeae ciprofloxacin susceptibility testing with molecular analyses and comparing the results over time.

Infective endocarditis in drug addicts: role of HIV infection and the diagnostic accuracy of Duke criteria.

BACKGROUND: Intravenous drug users (IVDUs) are at increased risk of infective endocarditis. Moreover, HIV infection is common in IVDUs, with a reported prevalence of 40-90%. The clinical features of IVDUs with infective endocarditis and HIV infection may be peculiar. Few data have been reported on the diagnostic accuracy of Duke criteria in IVDUs with or without HIV infection, and a comparison of these two populations is lacking. METHODS: The present study aimed to compare prospectively the clinical features of patients with infective endocarditis with or without HIV infection and to evaluate the diagnostic accuracy of Duke criteria in these patients. The study population consisted of 201 consecutive adult IVDUs with a suspected infective endocarditis (102 patients with HIV infection and 99 patients without HIV infection). RESULTS: Infective endocarditis was the final diagnosis in 40 of 102 patients (38.2%) with HIV infection and in 55 of 99 HIV-negative patients (55.6%). Despite similar baseline features, longer vegetations were recorded in infective endocarditis without HIV infection (23.7 +/- 7.1 mm versus 13.6 +/- 6.8 mm; P = 0.001). Patients with infective endocarditis and HIV infection had a higher total mortality at 2 months (respectively 12.5% versus 1.8%; P = 0.09); almost all the deaths were recorded in patients with AIDS or a CD4 cell count below 200 per microl, and no deaths were recorded in patients with HIV infection and a CD4 cell count > 500 per microl. CONCLUSIONS: Despite no identical clinical features, Duke criteria had a similar sensitivity, specificity and diagnostic accuracy in IVDUs with and without HIV infection.