Infections In Injection Drug Users Research Articles

Bedbugs as Vectors for Drug-Resistant Bacteria

To the Editor: Over the past 10 years in North America and western Europe, a resurgence of bedbugs (Cimex lectularius) has occurred (1). Although the basis for this resurgence is unclear, large bedbug infestations have been attributed to increased worldwide travel, altered insecticide management, and increased resistance to pesticides (2). Marginalized populations in large urban centers appear to be disproportionately affected; ≈30% of shelters in Toronto, Ontario, Canada, report bedbugs (1). We report recovery of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE) from bedbugs in Vancouver, British Columbia. Three patients, all residents of Vancouver’s Downtown Eastside—an impoverished community in Vancouver with high rates of homelessness, poverty, HIV/AIDS, and injection drug use (3)—were hospitalized and found to be infested with bedbugs. Hypothesizing that these parasites may be vectors for the transmission of antimicrobial drug–resistant pathogens, we collected 5 bedbugs and tested them for drug-resistant organisms. The bedbugs were homogenized and streaked onto standard microbiological media, including 5% sheep blood agar. Bacterial colonies were identified by using conventional and automated microbiological methods, and susceptibility testing was performed in accordance with Clinical Laboratory Standards Institute guidelines (4). For 2 patients, VRE was isolated from 1 bedbug each. These bacterial isolates were also resistant to ampicillin, teicoplanin, and aminoglycosides but susceptible to linezolid, quinupristin/dalfopristin, and tetracycline. For 1 other patient, MRSA was isolated from 3 bedbugs. All MRSA isolates had susceptibility patterns consistent with pulsed-field gel electrophoresis type USA300 (susceptible to vancomycin, clindamycin, trimethoprim/sulfamethoxasole, tetracycline, and rifampin; resistant to erythromycin). Despite investigations of transmissibility of numerous infectious agents, including transmissible blood-borne pathogens such as HIV and hepatitis B and C viruses, to our knowledge, no conclusive evidence has demonstrated disease transmission by bedbugs (5,6). Clinically, bedbug bites have been associated with cutaneous manifestations, most commonly pruritic wheals with a central hemorrhagic punctum (6). Excoriation at the site of a bite can cause further skin abrasion, thereby providing an entry point for colonizing bacteria, which can potentially result in folliculitic or cellulitic superinfections (5). S. aureus, which is commonly found on the skin and can cause cellulitis, has been reported to colonize the salivary glands of bedbugs for as long as 15 days (7). However, although transient and persistent forms of colonization may play a role in disease transmission, we did not differentiate these forms because the clinical bedbug specimens were processed at the time of receipt in the laboratory. Similar to other cities worldwide, Vancouver has seen an alarming increase in bedbugs, particularly in the Downtown Eastside, where 31% of residents have reported bedbug infestation (8). Enterococci commensally occupy the gastrointestinal tract. The recovery of VRE from bedbugs could result from the relatively unhygienic living conditions encountered in the Downtown Eastside and the high level of interconnectedness between St. Paul’s Hospital (where a large pool of patients with VRE colonization/infection reside) and the surrounding community. MRSA is also a substantial problem in the Downtown Eastside; it has been cultured from 54.8% of skin and soft tissue infections of patients seen at the emergency department of St. Paul’s Hospital (9). More recently, among wound infections in injection drug users in this community, 43% were colonized or infected with MRSA consistent with USA300, the predominant community-associated MRSA strain in Vancouver (10). The phenotype of the MRSA recovered from the bedbugs was consistent with community-associated MRSA and identical to that found on antibiograms from patients with MRSA infection who reside in this community. Given the high prevalence of MRSA (particularly USA300) in hotels and rooming houses in Vancouver’s Downtown Eastside, bedbugs may become colonized with community-associated MRSA. Consequently, these insects may act as a hidden environmental reservoir for MRSA and may promote the spread of MRSA in impoverished and overcrowded communities. Bedbugs carrying MRSA and/or VRE may have the potential to act as vectors for transmission. Further studies are needed to characterize the association between S. aureus and bedbugs. Bedbug carriage of MRSA, and the portal of entry provided through feeding, suggests a plausible potential mechanism for passive transmission of bacteria during a blood meal. Because of the insect’s ability to compromise the skin integrity of its host, and the propensity for S. aureus to invade damaged skin, bedbugs may serve to amplify MRSA infections in impoverished urban communities.

Joint Modeling of HCV and HIV Co-Infection among Injecting Drug Users in Italy and Spain Using Individual Cross-Sectional Data

The aim of the analysis presented in this paper is to study co-infection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) in injecting drug users (IDUs) using a joint modeling approach that makes use of multivariate statistical methods for current status data. Using marginal models, we estimate association measures between HCV and HIV infections at individual level, i.e., odds ratios and correlation coefficients, and we regress them against some risk factors, e.g., the length of the injecting career, the age at first injection, the ever sharing of syringes, and the frequency of current injecting. In addition, we fit random-effects models that take into account the individual heterogeneity in the acquisition of the infections. For our analysis, we use cross-sectional data from two independent serological surveys, one carried out in Italy (IT) in 2005 on 856 subjects, and the other in three Spanish (ES) cities, between 2001 and 2003, on 589 subjects. We found that the infections are positively associated within individuals, e.g., ORIT=2.56 with 95% confidence interval (CI) (1.43, 6.68) and ORES= 2.42, with 95% CI (1.41, 4.30). We found that the odds ratio and the correlation between HCV and HIV infections increase positively with the length of the injecting career. Moreover, they are found to be significantly positive in case IDUs have never shared syringes or report low injecting frequencies. The variance of the individual random effects is positive, e.g., σb2=0.34 (0.14, 0.62), indicating that there is significant individual heterogeneity in the acquisition of the infections. Our results show that a significant association between HCV and HIV infections within IDUs is related to significant individual heterogeneity in the acquisition of the infections. Indeed, the association between these infections in IDUs who report ever sharing syringes is not significant, which can be explained by a higher homogeneity in their behaviors and, therefore, in their acquisition of the infections.

Prevention of HIV infection among injection drug users in resource-limited settings.

Injection drug use contributes to considerable global morbidity and mortality associated with human immunodeficiency virus (HIV) infection and AIDS and other infections due to blood-borne pathogens through the direct sharing of needles, syringes, and other injection equipment. Of approximately 16 million injection drug users (IDUs) worldwide, an estimated 3 million are HIV infected. The prevalence of HIV infection among IDUs is high in many countries in Asia and eastern Europe and could exacerbate the HIV epidemic in sub-Saharan Africa. This review summarizes important components of a comprehensive program for prevention of HIV infection in IDUs, including unrestricted legal access to sterile syringes through needle exchange programs and enhanced pharmacy services, treatment for opioid dependence (ie, methadone and buprenorphine treatment), behavioral interventions, and identification and treatment of noninjection drug and alcohol use, which accounts for increased sexual transmission of HIV. Evidence supports the effectiveness of harm-reduction programs over punitive drug-control policies.

Effective Treatment of Injecting Drug Users With Recently Acquired Hepatitis C Virus Infection

Patients with acute hepatitis C virus (HCV) infection who receive treatment achieve high rates of sustained virologic response (SVR), but few studies have examined outcomes among injecting drug users (IDUs). We evaluated the efficacy of treatment of recent HCV infection in IDUs with acute and early chronic HCV. We analyzed data from the Australian Trial in Acute Hepatitis C-a prospective study of the natural history and treatment outcomes of patients with recent HCV infection. Participants eligible for the study had their first anti-HCV antibody-positive test result within the past 6 months and either acute clinical HCV within the past 12 months or documented anti-HCV seroconversion within 24 months. Participants with HCV received pegylated interferon-alfa-2a (180 microg/wk, n = 74); those with HCV/human immunodeficiency virus (HIV) co-infection received pegylated interferon-alfa-2a (180 microg/wk) with ribavirin (n = 35) for 24 weeks. From June 2004 to February 2008, 167 participants were enrolled in the Australian Trial in Acute Hepatitis C; 79% had injected drugs in the previous 6 months. Among 74 with only HCV, the SVRs were 55% and 72% by intention-to-treat and per-protocol analysis, respectively. In multivariate analyses, baseline factors independently associated with lower SVR included decreased social functioning and current opiate pharmacotherapy. Adherent participants had higher SVR rates (63% vs 29%; P = .025). Of the 35 participants with HCV/HIV co-infection, the SVRs were 74% and 75% by intention-to-treat and per-protocol analysis, respectively. Treatment of recent HCV infection among IDUs, including those with HIV co-infection, is effective. Strategies to engage socially marginalized individuals and increase adherence should improve treatment outcomes in this population.

Systematic Approach to the Treatment of HCV Infection in Injection Drug Users: Where are we Now?

Systematic Approach to the Treatment of HCV Infection in Injection Drug Users: Where are we Now?

Associations Between Availability and Coverage of HIV-Prevention Measures and Subsequent Incidence of Diagnosed HIV Infection Among Injection Drug Users

HIV-prevention measures specific to injection drug users (IDUs), such as opioid substitution treatment and needle-and-syringe programs, are not provided in many countries where injection drug use is endemic. We describe the incidence of diagnosed HIV infection in IDUs and the availability and coverage of opioid substitution and needle-and-syringe programs in the European Union and 5 middle- and high-income countries. Countries with greater provision of both prevention measures in 2000 to 2004 had lower incidence of diagnosed HIV infection in 2005 and 2006.

HIV among injecting drug users in Europe: increasing trends in the East

The human immunodeficiency virus (HIV) epidemic among injecting drug users (IDUs) shows different developments in different parts of the European region. In the countries of the European Union (EU) and the European Free Trade Association (EFTA), the rates of reported newly diagnosed cases of HIV infection in IDUs are mostly at stable and low levels or in decline. In contrast, those rates increased in 2007 in many of the other (eastern) countries in the World Health Organization (WHO) European Region, suggesting that the HIV epidemic among IDUs in Europe is still growing. In countries or regions where indicators of HIV incidence show upward trends, existing prevention measures may be insufficient and in need of strengthening. In the EU/EFTA region the larger availability of harm reduction measures such as opioid substitution treatment and needle and syringe programmes may have played a key role in containing the epidemic among IDUs.

Epidemic of severe Streptococcus pyogenes infections in injecting drug users in the UK, 2003–2004

During the late 1990s, increases in referrals to the national reference laboratory of Streptococcus pyogenes isolates from injecting drug users (IDUs) with severe soft tissue infection indicated an emerging problem in the UK, later confirmed during the 2003-2004 European enhanced surveillance (Strep-EURO) programme. In light of these findings, further analyses were undertaken in an attempt to understand the reasons behind this increase in referrals. Single and multivariable analyses were undertaken to compare clinical, microbiological and demographic characteristics of IDUs diagnosed with severe S. pyogenes infection during the 2003-2004 enhanced surveillance study with those of other cases arising during this same period. Temporal and spatial analyses were undertaken for IDUs to identify clustering, as a means of understanding the transmission dynamics underpinning this increase. Infections in IDUs were spread across the UK, with some concentration in northern England and London. IDUs presented with a wide range of clinical manifestations, including pneumonia, which was found to be significantly more common in IDUs (OR 3.00) than in other cases. Marked differences in type distributions were found between IDUs and other cases, in particular the concentration of emm/M83 (22% of IDUs, 2% of non-IDUs). These findings indicate that an epidemic of severe S. pyogenes infections in IDUs occurred in the UK, peaking in 2003. The explanation for this rise remains unclear.

High incidence of hepatitis C virus reinfection in a cohort of injecting drug users

An estimated 170 million people worldwide carry the hepatitis C virus (HCV), and in more developed countries the prevalence and incidence of HCV is particularly high among injecting drug users (IDUs). Spontaneous clearance of HCV infection and reinfection is well recognized but the level of protection against further infection conferred by HCV infection and clearance remains uncertain. We conducted a prospective study of HCV infection in IDUs recruited in Melbourne, Australia, using a much shorter median testing interval than in previous studies. Incidences of naive infection and reinfection were calculated by the person-year method and Cox proportional hazards regression used to adjust for covariates. A significantly higher HCV incidence rate was measured in previously infected IDUs (46.8% per year) compared with HCV-naive IDUs (15.5% per year). The hazard ratio for previously infected IDUs compared to HCV-naive IDUs, after adjustment for time-dependent covariates, was 2.54 (95% confidence interval, 1.11-5.78, P > |z| < 0.05). Viral persistence after reinfection appeared similar to that following naive infection. Our data suggest that HCV infection in IDUs is more likely following prior infection and clearance than in HCV-naive individuals, implying no increased immunity against further infection. This result has important implications for the future development of an HCV vaccine.

Extremely High Prevalence and Genetic Diversity of Hepatitis C Virus Infection among HIV‐Infected Injection Drug Users in Taiwan

An outbreak of human immunodeficiency virus (HIV) type 1 infection among injection drug users (IDUs) occurred in Taiwan, and thereafter, injection drug use became the most frequent risk factor for HIV infection in Taiwan. We sought to study the prevalence of and genotypes causing hepatitis C virus (HCV) infection among HIV-infected IDUs in Taiwan. A multicenter, longitudinal cohort study of 990 HIV-infected IDUs was conducted from 1993 through 2006. Blood samples were collected and analyzed for the presence of antibody to HCV and to determine the genotype of HCV. The overall prevalence of HCV infection among HIV-infected IDUs was 96.6%. The annual prevalence increased from 65.5% before 2002 to 98.6% in 2006. The main circulating HCV genotypes were 1a (accounting for 29.2% of samples), 6a (23.5%), and 3a (20.2%), whereas 1b, the most predominant genotype circulating in the general population in Taiwan, accounted for only 13.2% of samples. Genotypes 2b (accounting for 6.6% of samples), 6k (2.9%), 2a (1.6%), 6g (1.6%), and 3b (1.2%) were present in only a few IDUs. Multivariate logistic regression analysis revealed that duration of injection drug use and a travel history to China or Southeast Asia were significantly associated with infection due to HCV genotypes 1a, 3, and 6. Our study demonstrated a high prevalence of HCV infection among HIV-infected IDUs in Taiwan, with a predominance of infection due to genotypes 1a, 6a, and 3a, as a result of the impact of IDUs' behavior and their drug trafficking route. Our study revealed that HCV infection in IDUs originated from a geographically large transmission network that was mainly distinct from that associated with other HCV-infected individuals; this transmission network has also been documented in association with HIV infection in IDUs.

Epidemiology of hepatitis C virus infection among injection drug users in China: Systematic review and meta-analysis

Injection drug use (IDU) is the predominant mode of hepatitis C virus (HCV) transmission in China. This paper aims to provide a comprehensive and reliable tabulation of available data on the epidemiological characteristics and risk factors for HCV infection in injection drug users (IDUs) in China to help inform prevention programmes and guide future research. Data from articles and reports according to pre-defined criteria on HCV infection rates among IDUs of different regions, genders, ethnic backgrounds and risk factors (injecting practice, needle sharing, long duration, sex behaviour and co-infection status) were abstracted and pooled by meta-analysis. A systematic review was constructed based on both pooled data and representative viewpoints. Ninety-five percent confidence intervals (CI) of infection rates were calculated using the approximate normal distribution model. Odds ratios and 95% CI were calculated by fixed or random effects models. Publication bias was examined using Begg's test and Egger's test. Data manipulation and statistical analyses were undertaken using STATA 7.0 and RevMan 4.2. Epi Info 3.4.3 was used for map construction. The pooled prevalence of HCV infection among IDUs in China was 61.4% (95% CI 55.7-67.2%), and the epidemic was most severe in Hubei, Yunnan, Guangxi, Hunan and Xinjiang. No significant difference was found in HCV infection rates between male and female IDUs. A significant association was found between HCV infection and ethnic-minority status. IDUs were 9.24 times more likely to be infected with HCV than non-IDUs, while non-IDUs were more likely to be infected with HCV than members of the general population and other risk populations. There was no significant difference in the risk of HCV infection for needle-sharing IDUs and non-needle-sharing IDUs. A longer duration of IDU was associated with increased HCV prevalence. High-risk sexual practices were strongly associated with drug injection behaviours. Co-infection with human immunodeficiency virus (HIV) greatly increased the probability of HCV infection among IDUs, while the probability of hepatitis B virus infection remained similar for HCV-positive and HCV-negative IDUs in China. IDU continues to fuel the HCV/HIV epidemics spreading throughout China. Many pragmatic strategies are being implemented but need further evaluation.

Vitamin D Receptor Gene Haplotypes and Susceptibility to HIV‐1 Infection in Injection Drug Users

Vitamin D receptor (VDR) participates in multiple immune functions. Here, we determined whether VDR gene-sequence variations are associated with intersubject differences in the risk of acquiring human immunodeficiency virus type 1 (HIV-1) infection. We assessed this in 460 males exposed to HIV-1 by injection drug use (335 infected and 125 uninfected) and 124 seronegative healthy subjects. Multilocus logistic regression analysis revealed haplotypes for rs11568820, rs4516035, rs10735810, rs1544410, and rs17878969 polymorphisms showing association with protection to HIV-1 infection (odds ratio, 0.4 [95% confidence interval, 0.22-0.72]; P = .0025), which remained significant after correction for multiple testing. We infer that VDR haplotypes might influence the risk of HIV-1 acquisition.

Clostridium butyricum sepsis in an injection drug user with an indwelling central venous catheter

Clostridium novyi has been associated with a large outbreak of severe infections in injection drug users. A case of bacteraemia with Clostridium butyricum in an injection drug user is reported. During treatment for Staphylococcus aureus osteomyelitis, the patient used an indwelling central venous catheter to inject cocaine. He was admitted with C. butyricum sepsis that responded to broad spectrum antibiotics, including vancomycin. Local investigation for other cases was unrevealing; however, growth of an unusual pathogen in clinical specimens should be investigated as it may represent a sentinel event with public health implications.

HIV-1 incidence estimates using IgG-capture BED-enzyme immunoassay from surveillance sites of injection drug users in three cities of China

To detect recent infection in injection drug users (IDU) using the HIV-1 subtypes B, E, and D IgG-capture enzyme immunoassay (BED-CEIA) and estimate HIV-1 incidence in the IDU population in three cities of China. HIV-1-positive samples from IDU surveillance sentinel sites were collected for BED-CEIA, including 215 from city C (2001-2006), 433 from city D (2005), and 912 from city E (2000-2003). All 1560 samples were confirmed HIV positive with Western blot or alternative strategy. HIV-1 incidence was calculated with BED-CEIA statistics software. City C: Annualized HIV-1 incidence among IDU of surveillance sentinel sites was 0.57-0.93% from 2000 to 2001, and approximately 1.0% from 2004 to 2006. City D: In IDU surveillance sentinel sites in 2005, the HIV-1 incidence was estimated to be 9.6%, whereas the incidence in all drug users was 2.1%. City E: IDU sentinel surveillance indicated a slight decrease in HIV-1 incidence from 9.2% in 2000 to 7.9% in 2003. The HIV-1 incidence in IDU in city C was stable and relatively low. In contrast, there is a high HIV-1 incidence among IDU in cities D and E. The adjusted BED-CEIA estimated incidence rates indicate clearly that interventions must be strengthened continuously in IDU, especially in two Chinese cities.

Preventing hepatitis C virus infection in injection drug users: risk reduction is not enough

Preventing hepatitis C virus infection in injection drug users: risk reduction is not enough

Inappropriate Antibiotic Use in Soft Tissue Infections in Injection Drug Users—Reply

Inappropriate Antibiotic Use in Soft Tissue Infections in Injection Drug Users—Reply

Inappropriate Antibiotic Use in Soft Tissue Infections in Injection Drug Users

Inappropriate Antibiotic Use in Soft Tissue Infections in Injection Drug Users

Directly Observed Therapy with Azithromycin for Skin and Soft Tissue Infections in Injection Drug Users

This article has no abstract.

Demographic, risk behaviour and personal network variables associated with prevalent hepatitis C, hepatitis B, and HIV infection in injection drug users in Winnipeg, Canada

BackgroundPrevious studies have used social network variables to improve our understanding of HIV transmission. Similar analytic approaches have not been undertaken for hepatitis C (HCV) or B (HBV), nor used to conduct comparative studies on these pathogens within a single setting.MethodsA cross-sectional survey consisting of a questionnaire and blood sample was conducted on injection drug users in Winnipeg between December 2003 and September 2004. Logistic regression analyses were used to correlate respondent and personal network data with HCV, HBV and HIV prevalence.ResultsAt the multivariate level, pathogen prevalence was correlated with both respondent and IDU risk network variables. Pathogen transmission was associated with several distinct types of high-risk networks formed around specific venues (shooting galleries, hotels) or within users who are linked by their drug use preferences. Smaller, isolated pockets of IDUs also appear to exist within the larger population where behavioural patterns pose a lesser risk, unless or until, a given pathogen enters those networks.ConclusionThe findings suggest that consideration of both respondent and personal network variables can assist in understanding the transmission patterns of HCV, HBV, and HIV. It is important to assess these effects for multiple pathogens within one setting as the associations identified and the direction of those associations can differ between pathogens.

Group A Streptococcal Infections in Injection Drug Users in Barcelona, Spain

An unexplained resurgence of Group A streptococci (GAS) infections has been observed since the mid-1980s in the United States and Europe, particularly among intravenous drug users (IDUs). Several risk factors have been identified. Mutations in the capsule synthesis regulator genes (csrRS) have been associated with an increase in virulence. From January 1998 to December 2003, we conducted a prospective and retrospective descriptive analysis of invasive GAS soft-tissue infections in IDUs in Barcelona, Spain. Clinical features were collected, and we conducted a surveillance study to identify risk factors associated with GAS soft-tissue infections. We analyzed chromosomal DNA by low cleavage restriction enzymes and used pulsed-field gel electrophoresis (PFGE) and variable gene sequence typing (VGST) of the emm gene to disclose the epidemiologic relationship between the strains. We analyzed the influence of clonality (M-type) and mutations in csrRS genes of these strains on clinical features. We identified 44 cases, all of which were grouped in 3 clusters: fall 2000, fall 2002, and fall 2003. Cellulitis with or without abscesses (75%) and fever (90.9%) were the most common clinical manifestations. Distant septic complications were infrequent (18.2%). Although all patients had severe infections (mainly bacteremic needle abscesses), their outcome with antibiotic therapy, usually beta-lactam, was successful in all cases. However, surgery was needed in 40.9% of patients. Through the surveillance study we found that infected patients had a higher number of drug injections per day (odds ratio [OR], 18.84; 95% confidence interval [CI], 4.83-79.4; p<0.00001), shared paraphernalia for drug use more frequently (OR, 11.11; 95% CI, 3.24-39.04; p<0.0001), were in a higher proportion both currently unemployed and homeless (OR, 4.22; 95% CI, 1.5-12.15; p<0.0001), were not in a methadone maintenance program (OR, 0.03; 95% CI, 0-0.19; p<0.00001), and more often bought drugs at a specific site (OR, 33.92; 95% CI, 7.44-174.93; p<0.00001) and from a specific dealer (OR, 72; 95% CI, 8-3090; p<0.00001), compared with patients not infected. The fall 2000 cluster was polyclonal, whereas the other 2 clusters were mainly due to the same strain of GAS (emm 25.2), and were defined as epidemic outbreaks. Clinically, the cases due to the clonal strain presented abscesses and needed surgery more frequently (p<0.001 and p=0.005, respectively). On the other hand, mutations in the csrRS genes were not associated with invasive GAS soft-tissue infection. There has been an increase in the number of cases of invasive GAS soft-tissue infections in IDUs in Barcelona, which seems to be related to drug users' habits and their socioeconomic status. Clonality (emm 25.2) but not mutations in the csrRS genes was associated with more severe GAS soft-tissue infections.