Outbreak among drug users caused by a clonal strain of group A streptococcus

Challenges posed by COVID-19 to people who inject drugs and lessons from other outbreaks

INTRODUCTION

In light of the COVID-19 pandemic, considerable effort is going into identifying and protecting those at risk. Criminalization, stigmatization and the psychological, physical, behavioural and economic consequences of substance use make people who inject drugs (PWID) extremely vulnerable to many infectious diseases. While relationships between drug use and blood-borne and sexually transmitted infections are well studied, less attention has been paid to other infectious disease outbreaks among PWID.

DISCUSSION

COVID-19 is likely to disproportionally affect PWID due to a high prevalence of comorbidities that make the disease more severe, unsanitary and overcrowded living conditions, stigmatization, common incarceration, homelessness and difficulties in adhering to quarantine, social distancing or self-isolation mandates. The COVID-19 pandemic also jeopardizes essential for PWID services, such as needle exchange or substitution therapy programmes, which can be affected both in a short- and a long-term perspective. Importantly, there is substantial evidence of other infectious disease outbreaks in PWID that were associated with factors that enable COVID-19 transmission, such as poor hygiene, overcrowded living conditions and communal ways of using drugs.

CONCLUSIONS

The COVID-19 crisis might increase risks of homelessnes, overdoses and unsafe injecting and sexual practices for PWID. In order to address existing inequalities, consultations with PWID advocacy groups are vital when designing inclusive health response to the COVID-19 pandemic.

Invasive Group A Streptococcal Infections Among People Who Inject Drugs and People Experiencing Homelessness in the United States, 2010-2017

BACKGROUND

Reported outbreaks of invasive group A Streptococcus (iGAS) infections among people who inject drugs (PWID) and people experiencing homelessness (PEH) have increased, concurrent with rising US iGAS rates. We describe epidemiology among iGAS patients with these risk factors.

METHODS

We analyzed iGAS infections from population-based Active Bacterial Core surveillance (ABCs) at 10 US sites from 2010 to 2017. Cases were defined as GAS isolated from a normally sterile site or from a wound in patients with necrotizing fasciitis or streptococcal toxic shock syndrome. GAS isolates were emm typed. We categorized iGAS patients into four categories: injection drug use (IDU) only, homelessness only, both, and neither. We calculated annual change in prevalence of these risk factors using log binomial regression models. We estimated national iGAS infection rates among PWID and PEH.

RESULTS

We identified 12 386 iGAS cases; IDU, homelessness, or both were documented in ~13%. Skin infections and acute skin breakdown were common among iGAS patients with documented IDU or homelessness. Endocarditis was 10-fold more frequent among iGAS patients with documented IDU only versus those with neither risk factor. Average percentage yearly increase in prevalence of IDU and homelessness among iGAS patients was 17.5% and 20.0%, respectively. iGAS infection rates among people with documented IDU or homelessness were ~14-fold and 17- to 80-fold higher, respectively, than among people without those risks.

CONCLUSIONS

IDU and homelessness likely contribute to increases in US incidence of iGAS infections. Improving management of skin breakdown and early recognition of skin infection could prevent iGAS infections in these patients.

Infectious Diseases: The Role of the Healthcare Professional

For the healthcare professional dealing with infections presents two main problems. First, managing detainees or police personnel who have contracted a disease and may be infectious or unwell, and second, handling complainants of assault, including police officers, who have potentially been exposed to an infectious disease. This chapter addresses some general principles of infection control and safety in the working environment and then goes on to discuss some infections that may be encountered in police custody and how they can best be managed.

Population-based surveillance of invasive group A streptococcal disease in British Columbia: 1996 to 1998

OBJECTIVE

To identify and describe all cases of invasive group A streptococcal (GAS) infection occurring in British Columbia during a two-year period.

DESIGN

Active, laboratory-based surveillance with supplemental case description.

SETTING

Forty community and regional hospitals and the provincial laboratory participated, encompassing all health regions.

POPULATION STUDIED

Entire provincial population from April 1, 1996 to March 31, 1998.

MAIN RESULTS

Over the 24-month surveillance period, 182 eligible cases were identified, yielding a mean annual incidence rate of 2.3/100,000. Patients ranged in age from two to 91 years, with a mean of 39.1 years. Soft tissue infections accounted for 89 of 130 cases (68.5%) with a defined clinical syndrome, 20 of which were necrotizing fasciitis. Injection drug use was described in 55 patients, who, as a group, were younger, more likely to have soft tissue infections and less likely to die of infection than nondrug users. Other risk factors for infection included HIV infection (19 patients); skin damage (26 patients, damage independent of injection drug use); chronic illness (27 patients); and immunosuppresion (three patients). Death from GAS infection occurred in 15 of 131 (11.5%) cases with known outcome, yielding an annual case fatality rate of 1.9/million population. Among necrotizing faciitis cases, the mortality rate was 30%.

CONCLUSIONS

Invasive GAS infections are rare in British Columbia and tend to involve persons with chronic illness or prior skin trauma, especially injection drug abuse, which accounted for nearly half of the cases.

Epidemiological and molecular analysis of Streptococcus pyogenes isolates causing invasive disease in Spain (1998-2009): comparison with non-invasive isolates

The incidence, clinical manifestations, and circulating clones involved in Streptococcus pyogenes invasive disease was analyzed in two regions of Spain between 1998 and 2009. The annual average incidence of invasive disease was 2 episodes per 100,000 inhabitants (3.1 for children and 1.9 for adults). The most frequent clinical manifestations were cellulitis (41.3%), bacteremia without focus (19.0%), streptococcal toxic shock syndrome (12.6%), and pneumonia (7.7%). Among 247 invasive isolates analyzed, the most prevalent clones were emm1/ST28 (27.9%), emm3/ST15-406 (9.8%), and emm4/ST39 (6.5%). The emm1/ST28 clone was the only clone detected each year throughout the study period and was associated with more than one third of all fatal outcomes. When invasive isolates were compared with 1,189 non-invasive isolates, the emm1/ST28 clone was significantly associated with invasive disease. The speA and ssa genes were more frequent among invasive emm1 and emm4 isolates, respectively. Forty-two (17%) invasive isolates were resistant to erythromycin (21 harbored the mef gene and 21 the ermB or ermA genes). Twenty-two (8.9%) isolates had reduced susceptibility to ciprofloxacin (minimum inhibitory concentration [MIC] 2-8 μg/mL) and 32 (13%) were tetracycline-resistant (tetM or tetO gene). In conclusion, the emm1 type was overrepresented among invasive cases and was associated with high mortality rates.

Shooting up: the interface of microbial infections and drug abuse

Illicit drug control has been on the global agenda for more than a century. Infections have long been recognized as one of the most serious complications of drug abuse. Drug users are susceptible to pulmonary, endovascular, skin and soft tissue, bone and joint, and sexually transmitted infections caused by a wide range of bacterial, viral, fungal and protozoal pathogens. In addition, injection drug users are at increased risk for parenterally acquired infections such as human immunodeficiency virus, hepatitis B virus, hepatitis C virus, tetanus and malaria. Factors related to drug use, such as unsterile injection practices, contaminated drug paraphernalia and drug adulterants, increase the exposure to microbial pathogens. Illicit drugs also affect several components of the complex immune system and thus modulate host immunity. In addition, lifestyle practices such as multiple sexual partners, overcrowded housing arrangements and malnutrition serve as co-factors in increasing the risk of infection. In this review we present an overview of the unique aspects of microbial pathogenesis, immune modulation and common infections associated with drug use. We have restricted the definition of drug abuse to the use of illegal drugs (such as opiates, marijuana, cocaine, heroin and amphetamines), not including alcohol and nicotine.

Infectious Diseases: The Role of the Forensic Physician

Infections have plagued doctors for centuries, both in the diagnosis of the specific diseases, and the identification and subsequent management of the causative agents. There is a constant need for information as new organisms emerge, existing ones develop resistance to current drugs or vaccines and there are changes in epidemiology and prevalence. In the twenty-first century, obtaining this information has never been more important. Population migration, and the relatively low cost of flying, means that unfamiliar infectious diseases may be brought into industrialised countries. An example of this was an outbreak of severe acute respiratory syndrome (SARS), which was first recognised in 2003. Despite modern technology and a huge input of money, it took months for the agent to be identified, a diagnostic test to be produced, and a strategy for disease reporting and isolation to be established.

Prevalence and predictors of injecting-related injury and disease among clients of Australia's needle and syringe programs

OBJECTIVE

To identify lifetime prevalence and predictors of self-reported injecting-related injuries and diseases (IRID) and/or injecting-related problems (IRP) among a national cross-sectional sample of injecting drug users.

METHODS

1,961 clients of 45 needle and syringe programs (NSPs) who participated in the 2006 Australian NSP Survey self-completed an item regarding lifetime experience of eight separate IRIDs and IRPs.

RESULTS

Sixty-nine per cent of participants reported a history of IRID/IRP, with a mean of 1.9 injuries/problems (range 0-8). Lifetime prevalence of specific injuries/problems ranged from problems finding a vein (43%) to endocarditis (4%). Factors independently associated with IRID/IRP included bisexual identity; daily or more frequent injecting; injection of pharmaceutical preparations; female gender; longer injecting history; and hepatitis C antibody-positive serostatus.

CONCLUSIONS

Consistent with existing literature, results suggest that vascular injury and localised infections are common among IDUs; and that treatment-seeking is often delayed until serious complications arise.

IMPLICATIONS

Findings support the imperative for co-ordinated and timely treatment and prevention activities to reduce the severity and burden of these prevalent injecting outcomes.

Invasive group A streptococcal infection in injecting drug users and non-drug users in a single UK city

OBJECTIVES

Injecting drug users (IDU) represent an increasing proportion of patients with invasive group A streptococcal (GAS) disease. Our aims were to characterise the clinical presentation and strains causing GAS bacteremia in IDU from a single UK city (Brighton and Hove), and to compare this patient group with non-drug users (non-DU) with GAS bacteremia.

METHODS

Consecutive GAS blood culture isolates from twenty-two IDU and twenty-two non-DU presenting to the city hospital were studied. Clinical features, strain emm typing and superantigen toxin genotyping were investigated.

RESULTS

GAS invasive disease presented differently in IDU compared to non-DU with a predominance of injection site abscesses and lower mortality in IDU. GAS strains from IDU were predominantly emm82 and emm83 types, which are uncommon in the UK and emm82 strains appeared clonal. The non-DU GAS strains demonstrated a broader range of emm types including most frequently emm1 and emm89. There was no major difference in superantigen gene profile between the isolate groups.

CONCLUSION

The distinct presentation of invasive GAS disease in IDU compared with non-DU was associated with distinct emm types, a predominance of abscesses, and low mortality, although the small numbers preclude definitive conclusions. Further study is required to establish if these findings reflect strain differences or epidemiological differences in colonisation patterns and injecting practice.

Molecular characterization of clinical isolates of M non-typable group A streptococci from invasive disease cases

Currently there are 93 validated M serotypes of Streptococcus pyogenes, Lancefield group A streptococcus (GAS), and >130 emm genotypes. A marked increase in the number of non-typable GAS isolates (2 % in 2000, 4 % in 2001 and 9 % in 2002) from invasive disease cases referred to the authors' reference laboratory was noted during 2000–2002. A total of 217 (92 %) were from blood cultures, 14 (6 %) from deep abscesses and five (2 %) from aspirates. The clinical manifestations included bacteraemia, septicaemia, cellulitis, meningitis, necrotizing fasciitis and toxic-shock syndrome. In order to establish whether this increase was due to the emergence of novel types or the unavailability of M-typing sera, these isolates were subjected to emm sequencing. A total of 144 isolates (61 %) belonged to M types for which sera were no longer available; 112 (48 %) belonged to higher M types, including emm83.1 (9 %), emm94 (8 %) emm87 (6 %) and emm89 (6 %); and 32 (13 %) belonged to lower M types that were not commonly isolated in the UK, and included M25, M43, M49, M64, M73 and M74. Sixty-six (28 %) of the isolates belonged to newly designated emm types. Other isolates belonged to the novel emm types st2147, STNS1033 and st854, recently registered in the Centers for Disease Control (CDC) database by other laboratories. One novel emm type, st2161, was isolated from an injecting drug user. There were differences in the type distribution of these isolates according to geographic location. However, 90 % of emm93, one of seven predominant emm types identified amongst the collection of M non-typable (MNT) isolates, were isolated from the London region.

Superantigen gene profile, emm type and antibiotic resistance genes among group A streptococcal isolates from Barcelona, Spain

Group A streptococcus (GAS) has been described as an emerging cause of severe invasive infections. A retrospective hospital-based study was conducted, including GAS isolates causing invasive or non-invasive infections from January 1999 to June 2003 in Barcelona. Demographic and clinical information on the invasive cases was obtained from medical files. GAS isolates collected from 27 patients with invasive infections and 99 patients with non-invasive infections were characterized by emm type and subtype, superantigen (SAg) gene profile (speA–C, speF–J, speL, speM, ssa and smeZ), allelic variants of speA and smeZ genes, antibiotic susceptibility and genetic resistance determinants. The most prevalent emm type was emm1 (17.5 %), followed by emm3 (8.7 %), emm4 (8.7 %), emm12 (7.1 %) and emm28 (7.1 %). The smeZ allele and SAg gene profiles were closely associated with the emm type. The speA2, speA3 and speA4 alleles were found in emm1, emm3 and emm6 isolates, respectively. Overall, 27.8, 25.4 and 11.9 % of isolates were resistant to erythromycin, tetracycline or both agents, respectively. Reduced susceptibility to ciprofloxacin and levofloxacin (MIC 2–4 μg ml−1) was found in 3.2 % of isolates. mef(A)-positive emm types 4, 12 and 75, and erm(B)-positive emm types 11 and 25 were responsible for up to 80 % of the erythromycin-resistant isolates. No significant differences in emm-type distribution, SAg gene profile or resistance rates were found between invasive and non-invasive isolates. The SAg and antibiotic resistance genes appeared to be associated with the emm type and were independent of the disease type.

Group A streptococcal infections in injection drug users in Barcelona, Spain: epidemiologic, clinical, and microbiologic analysis of 3 clusters of cases from 2000 to 2003

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.

Increasing incidence of group A streptococcal infections amongst injecting drug users in England and Wales

During 2000, the UK witnessed a sudden increase in severe infections and related deaths in injecting drug users (IDUs), sparking off a UK-wide investigation. A worrying upward trend in severe group A streptococcal (GAS) infections has recently been observed in IDUs based upon isolate referrals to the PHLS Respiratory and Systemic Infection Laboratory. Most cases were young male adults who presented with skin sepsis and bacteraemia. Serotyping revealed a diverse range of M types, with higher types predominating in some geographical areas. The data suggest that GAS invasive soft-tissue infections may present in an epidemic fashion among IDUs in the absence of a common source.

Skin and Soft Tissue Infections in Injection Drug Users

Skin and soft tissue infections (SSTIs) are common among injection drug users (IDUs). Subcutaneous and intramuscular injection ("skin-popping") and the injection of "speedballs" (a mixture of heroin and cocaine) are important risk factors for SSTIs in this patient population. Female IDUs appear to be at greater risk of SSTIs than male IDUs, probably because of more difficult venous access. There are conflicting data regarding the impact of HIV and human T-cell lymphotrophic virus II infection on the risk of SSTIs in IDUs; however, an expanding body of evidence suggests that immunosuppressive effects of the drugs themselves may play a role. Most information regarding the microbiology of SSTIs in IDUs comes from data on skin and subcutaneous abscesses, where Staphylococcus aureus and organisms that originate from the oral flora predominate. Clonal outbreaks and uncommon infections including tetanus, wound botulism, and a sepsis/myonecrosis syndrome due to Clostridium species have been recently reported in IDUs.

New methods to investigate infectious disease transmission and pathogenesis--Staphylococcus aureus disease in drug users

Staphylococcus aureus is the single most important bacterial pathogen in infections among drug users. It is responsible for several diseases, ranging from superficial cutaneous abscesses to life-threatening intravascular infections. Although the nature of these infections is well described in published work, there is limited understanding of their epidemiology and pathogenesis. This limitation is in part due to the difficulty of studying disease transmission among drug users in the community, and the limitations of the investigative tools that have so far been used. We review the current understanding of the pathogenesis of staphylococcal disease in drug users and argue for the integration of molecular epidemiological techniques and social network methodology to increase our understanding of the basis for the persistence, distribution, and transmission dynamics of S aureus among drug users. Finally, we propose a framework for investigating the transmission of pathogens in community-based settings.

Strains of Staphylococcus aureus obtained from drug-use networks are closely linked

Drug users have a higher incidence of colonization with Staphylococcus aureus than does the general population, and, as a result, they are at increased risk of infection with their colonizing strain. The purpose of this study was to examine the role of drug-use risk networks in S. aureus transmission, the similarity of S. aureus isolates within these networks, and the possible role of inhalation drug use paraphernalia in the transmission of S. aureus. Strains of S. aureus are shared among colonized inhalation drug users within drug-use risk networks. It suggests that patterns of drug use and the geographic location where drug sharing occurs are major contributors to the transfer of staphylococci and, as a result, to the high prevalence of staphylococcal colonization and perhaps disease in this population.

Skin and soft tissue infections in injection drug users

Skin and soft tissue infections are the most common cause for hospital admission of injection drug users. Cutaneous and subcutaneous abscesses are the most frequent type of SSTI and occur most commonly when drug users are no longer able to inject intravenously and resort to injection directly into skin or muscle. Abscesses may be difficult to differentiate from uncomplicated cellulitis or may be confused with pseudoaneurysms, hematoma, phlegmon, or thrombosed vein. Special studies, including ultrasonography; CT scans, and MR imaging; or careful incision and inspection may be necessary to clarify the extent of infection and the presence of abscess. These procedures may also help differentiate a subcutaneous abscess from a vascular structure. Uncomplicated cellulitis most commonly responds to antibiotic therapy directed toward Staphylococcus aureus and Streptococcus spp. In several recent studies, cutaneous and subcutaneous abscesses have been found to be caused by polymicrobial infections and to include anaerobic organisms as well as aerobic gram-positive cocci in a little more than 50% of cases. Complete, often repeated, incision and drainage is a prerequisite for successful outcome in these cases. Complications of SSTI are many and are potentially life threatening. They include direct extension of subcutaneous abscess into vital areas or structures, necrotizing fasciitis and myositis, bacteremia, and sepsis. An outbreak of a highly lethal SSTI that recently occurred in Scotland, Ireland, and England seems to have resulted from infection with Clostridia spp, including C. novyi and C. perfringens. A rare but well-documented SSTI in injection drug users is pyomyositis, an abscess-forming infection of skeletal muscle. More than 20 cases have been reported in temperate climates to date. Although not life-threatening, chronic cutaneous venous ulcers of the lower extremities are common and debilitating, requiring long-term multidisciplinary care for successful healing.