Prevalence of Simkania negevensis in chlorinated water from spa swimming pools and domestic supplies

Development of a duplex q-PCR for the simultaneous detection of Parachlamydia acanthamoebae and Simkania negevensis in environmental and clinical samples

Parachlamydia acanthamoebae and Simkania negevensis, two Chlamydia-like bacteria, have been recently recognized as emerging human respiratory pathogens. The prevalence and frequency of these bacteria in the environment and among atypical pneumonia patients are still underestimated by classical cultures, immunohistochemistry and serology which are non-specific, long and tedious methods. This study aims to develop a new duplex probe-based q-PCR assay for the simultaneous detection and quantification of P. acanthamoebae and S. negevensis. The selected hydrolysis probes displayed no cross-reaction with the closely related Chlamydia or the other tested waterborne pathogens. The assay achieved a large dynamic range for quantification (from 5 × 10⁶ to 5 DNA copies/reaction). Efficiencies of FAM and JOE label probes weren't affected when they were combined. They were close to 100%, indicating the linear amplification. The application of this diagnostic tool resulted in 9/47 (19%) and 4/47 (8.5%) positive water samples for P. acanthamoebae and S. negevensis, respectively. P. acanthamoebae was also covered from 2/78 (2.5%) respiratory specimens and only one case (1/200 = 0.5%) of P. acanthamoebae and SARS-CoV-2 co-infection was noticed. While S. negevensis wasn't detected in clinical samples, the developed duplex q-PCR was shown to be an accurate, highly sensitive, and robust diagnostic tool for the detection and quantification of P. acanthamoebae and S. negevensis.

First evidence for the existence of Simkania negevensis in the genitalia of human females

INTRODUCTION

Simkania negevensis has been linked to some respiratory and non-respiratory diseases. However, there is still a serious lack of clinical investigations that attempt to determine possible body sites that could be inhabited by this microorganism and evaluate its true pathogenic capacity. The goal of this study was to examine the potential presence of Simkania and its prevalence in the genital tract of human adult females.

METHODS

Lower vaginal swabs from 169 Jordanian adult females who attended Obstetrics and Gynecology clinic were collected and tested for Simkania DNA by PCR method.

RESULTS

The presence of bacterial nucleic acids was confirmed in the genital system of adult females with an overall prevalence of 24.26% (41/169). Interestingly, the positivity of Simkania DNA was significantly higher in women of reproductive age than females of non-reproductive age (28.03% versus 10.81%; p≤0.05). Moreover, the presence of S. negevensis was evident in approximately 43% of females suffering from vaginal itching and/or abnormal discharge, exhibiting about two-fold increase in the positivity rate compared to detection rates assessed for women who attended the clinic for routine checkup or menstruation problems. However, the current work failed to find any link between the bacterial agent and spontaneous abortion (miscarriage).

CONCLUSIONS

This study showed for the first time the presence of S. negevensis in the genitalia of human females. These novel data could provide a basis to clarify the exact role of S. negevensis in the female genitalia and its potential involvement in genital system disorders.

The Presence of Opportunistic Premise Plumbing Pathogens in Residential Buildings: A Literature Review

Opportunistic premise plumbing pathogens (OPPP) are microorganisms that are native to the plumbing environment and that present an emerging infectious disease problem. They share characteristics, such as disinfectant resistance, thermal tolerance, and biofilm formation. The colonisation of domestic water systems presents an elevated health risk for immune-compromised individuals who receive healthcare at home. The literature that has identified the previously described OPPPs (Aeromonas spp., Acinetobacter spp., Helicobacter spp., Legionella spp., Methylobacterium spp., Mycobacteria spp., Pseudomonas spp., and Stenotrophomonas spp.) in residential drinking water systems were systematically reviewed. By applying the Preferred reporting items for systematic reviews and meta-analyses guidelines, 214 studies were identified from the Scopus and Web of Science databases, which included 30 clinical case investigations. Tap components and showerheads were the most frequently identified sources of OPPPs. Sixty-four of these studies detected additional clinically relevant pathogens that are not classified as OPPPs in these reservoirs. There was considerable variation in the detection methods, which included traditional culturing and molecular approaches. These identified studies demonstrate that the current drinking water treatment methods are ineffective against many waterborne pathogens. It is critical that, as at-home healthcare services continue to be promoted, we understand the emergent risks that are posed by OPPPs in residential drinking water. Future research is needed in order to provide consistent data on the prevalence of OPPPs in residential water, and on the incidence of waterborne homecare-associated infections. This will enable the identification of the contributing risk factors, and the development of effective controls.

First evidence for the existence of Simkania negevensis in the genitalia of human females

INTRODUCTION

Simkania negevensis has been linked to some respiratory and non-respiratory diseases. However, there is still a serious lack of clinical investigations that attempt to determine possible body sites that could be inhabited by this microorganism and evaluate its true pathogenic capacity. The goal of this study was to examine the potential presence of Simkania and its prevalence in the genital tract of human adult females.

METHODS

Lower vaginal swabs from 169 Jordanian adult females who attended Obstetrics and Gynecology clinic were collected and tested for Simkania DNA by PCR method.

RESULTS

The presence of bacterial nucleic acids was confirmed in the genital system of adult females with an overall prevalence of 24.26% (41/169). Interestingly, the positivity of Simkania DNA was significantly higher in women of reproductive age than females of non-reproductive age (28.03% versus 10.81%; p≤0.05). Moreover, the presence of S. negevensis was evident in approximately 43% of females suffering from vaginal itching and/or abnormal discharge, exhibiting about two-fold increase in the positivity rate compared to detection rates assessed for women who attended the clinic for routine checkup or menstruation problems. However, the current work failed to find any link between the bacterial agent and spontaneous abortion (miscarriage).

CONCLUSIONS

This study showed for the first time the presence of S. negevensis in the genitalia of human females. These novel data could provide a basis to clarify the exact role of S. negevensis in the female genitalia and its potential involvement in genital system disorders.

Legionellosis in Japan: A Self-inflicted Wound?

Legionellosis is a serious bacterial infection characterized by atypical pneumonia primarily due to infection with Legionella pneumophila, and bathing can be a potential cause of this infection. Legionellosis was first identified in 1977, and it is caused by Gram-negative bacteria belonging to the genus Legionella. Legionellosis remains an important public health threat, particularly in Japan, where the population is rapidly aging, thereby becoming more at risk of developing severe disease and accompanying life-threatening pneumonia. The bacteria are most commonly transmitted via the inhalation of contaminated aerosols produced and broadcast via water sprays, jets or mists. Infection can also occur via the aspiration of contaminated water or ice, or through inhalation of contaminated dust. Because the signs and symptoms of Legionnaires' disease (LD), as well as radiographic imaging are similar to pneumonia caused by other pathogens, a specific diagnostic test is required, such as a urine antigen detection test. Six clinical and laboratory parameters, a high body temperature, a non-productive cough, low serum sodium and platelet counts, and high lactate dehydrogenase (LDH) and c-reactive protein concentrations can be used to reliably predict the likelihood of LD. The first choices for chemotherapy are fluoroquinolone and macrolide antibiotic drugs. The main goals of LD prevention measures are 1) the prevention of microbial growth and biofilm formation, 2) the removal of all biofilm formed on equipment and in facilities, 3) minimizing aerosol splash and spread, and 4) minimizing bacterial contamination from external sources. It is apparent that, in Japan, where hot spring (onsen) bathing is common among aged people, strict regulations need to be in place - and enforced - to ensure that all Japanese onsens and spas provide a safe environment and undertake regular, effective infection control practices.

Development of a new TaqMan-based PCR assay for the specific detection and quantification of Simkania negevensis

Simkania negevensis is an emerging Chlamydia-like bacterium related to human respiratory diseases. An early and accurate detection of this pathogen could be useful to monitor the potential infectious risks and to set suitable outbreak control measures. In Tunisia, distribution and abundance of S. negevensis remain until now largely unknown. In the present work, a qPCR assay, targeting the 16S rRNA gene, for fast detection and quantification of S. negevensis was developed and validated. A high specificity for S. negevensis detection displaying no cross-reaction with the closely related Chlamydia spp. or the other tested microorganisms was noticed. qPCR assay performance was considered very satisfying with detection limits of 5 DNA copies per reaction. qPCR assay validation was performed by screening 37 clinical specimens and 35 water samples. S. negevensis wasn't detected in respiratory samples, but it was found in four cases of water samples. We suggest that the qPCR assay developed in this study could be considered sufficiently characterized to initiate the quantification of S. negevensis in environmental samples.

Simkania negevensis in Crohn's Disease

BACKGROUND

Simkania negevensis is an obligate intracellular Gram-negative bacterium (family Simkaniaceae, order Chlamydiales) that has been isolated from domestic and mains water supplies, is able to infect human macrophages, and can induce an inflammatory response in the host.

METHODS

From June to December 2016, in a single-center observational study, colonic Crohn's disease patients and controls (subjects undergoing screening for colorectal cancer) underwent blood tests to identify serum-specific immunoglobulin G (IgG) and immunoglobulin A (IgA) to S. negevensis and a colonoscopy with biopsies for detection of S. negevensis DNA by polymerase chain reaction (PCR).

RESULTS

Forty-three Crohn's disease patients and 18 controls were enrolled. Crohn's disease patients had higher prevalence of IgA antibodies to S. negevensis compared with controls (20.9% versus 0%, p = 0.04). Simkaniaceae negevensis DNA was detected in 34.9% and 5.6% of intestinal biopsies in Crohn's disease patients and controls, respectively (p = 0.02). All Crohn's disease patients with PCR-positive biopsies for S. negevensis were IgG seropositive, with specific IgA in 60% of them (p < 0.001). Immunosuppressive therapies, extraintestinal manifestations, or disease activity did not influence the presence of S. negevensis in the Crohn's disease population.

CONCLUSIONS

We identified S. negevensis in Crohn's disease patients by demonstrating the presence of S. negevensis mucosal DNA and seropositivity to the bacterium. These results could support the presence of an acute or persistent S. negevensis infection and suggest a possible role in the pathogenesis of Crohn's disease.

Relationships between Microbial Indicators and Pathogens in Recreational Water Settings

Fecal pollution of recreational waters can cause scenic blight and pose a threat to public health, resulting in beach advisories and closures. Fecal indicator bacteria (total and fecal coliforms, Escherichia coli, and enterococci), and alternative indicators of fecal pollution (Clostridium perfringens and bacteriophages) are routinely used in the assessment of sanitary quality of recreational waters. However, fecal indicator bacteria (FIB), and alternative indicators are found in the gastrointestinal tract of humans, and many other animals and therefore are considered general indicators of fecal pollution. As such, there is room for improvement in terms of their use for informing risk assessment and remediation strategies. Microbial source tracking (MST) genetic markers are closely associated with animal hosts and are used to identify fecal pollution sources. In this review, we examine 73 papers generated over 40 years that reported the relationship between at least one indicator and one pathogen group or species. Nearly half of the reports did not include statistical analysis, while the remainder were almost equally split between those that observed statistically significant relationships and those that did not. Statistical significance was reported less frequently in marine and brackish waters compared to freshwater, and the number of statistically significant relationships was considerably higher in freshwater (p < 0.0001). Overall, significant relationships were more commonly reported between FIB and pathogenic bacteria or protozoa, compared to pathogenic viruses (p: 0.0022⁻0.0005), and this was more pronounced in freshwater compared to marine. Statistically significant relationships were typically noted following wet weather events and at sites known to be impacted by recent fecal pollution. Among the studies that reported frequency of detection, FIB were detected most consistently, followed by alternative indicators. MST markers and the three pathogen groups were detected least frequently. This trend was mirrored by reported concentrations for each group of organisms (FIB > alternative indicators > MST markers > pathogens). Thus, while FIB, alternative indicators, and MST markers continue to be suitable indicators of fecal pollution, their relationship with waterborne pathogens, particularly viruses, is tenuous at best and influenced by many different factors such as frequency of detection, variable shedding rates, differential fate and transport characteristics, as well as a broad range of site-specific factors such as the potential for the presence of a complex mixture of multiple sources of fecal contamination and pathogens.

Legionellosis Associated with Recreational Waters: A Systematic Review of Cases and Outbreaks in Swimming Pools, Spa Pools, and Similar Environments

Legionella spp. is widespread in many natural and artificial water systems, such as hot water distribution networks, cooling towers, and spas. A particular risk factor has been identified in the use of whirlpools and hot tubs in spa facilities and public baths. However, there has been no systematic synthesis of the published literature reporting legionellosis cases or outbreaks related to swimming/spa pools or similar environments used for recreational purposes (hot springs, hot tubs, whirlpools, natural spas). This study presents the results of a systematic review of the literature on cases and outbreaks associated with these environments. Data were extracted from 47 articles, including 42 events (17 sporadic cases and 25 outbreaks) and 1079 cases, 57.5% of which were diagnosed as Pontiac fever, without any deaths, and 42.5% were of Legionnaires' disease, with a fatality rate of 6.3%. The results are presented in relation to the distribution of Legionella species involved in the events, clinical manifestations and diagnosis, predisposing conditions in the patients, favourable environmental factors, and quality of the epidemiological investigation, as well as in relation to the different types of recreational water sources involved. Based on the epidemiological and microbiological criteria, the strength of evidence linking a case/outbreak of legionellosis with a recreational water system was classified as strong, probable, and possible; in more than half of the events the resulting association was strong.

Lethal outcome of granulomatous acanthamoebic encephalitis in a man who was human immunodeficiency virus-positive: a case report

Background

Acanthamoeba species can cause disseminating infections in immunocompromised individuals.

Case presentation

Here, we report a case of granulomatous acanthamoebic encephalitis with a lethal outcome in a 54-year-old German man who was human immunodeficiency virus-positive. The diagnosis was based on symptoms of progressive neurological deficits, including sensorimotor paralysis of his right leg and deteriorating alertness. Due to the rapid course and rather late diagnosis of the infection, effective treatment could not be applied and he died 12 days after hospital admission.

Conclusions

To the best of our knowledge, this is the second case of granulomatous acanthamoebic encephalitis reported within Germany. Our case highlights the importance of early diagnosis of granulomatous acanthamoebic encephalitis to prevent fatal outcome.

Seroprevalence of a "new" bacterium, Simkania negevensis, in renal transplant recipients and in hemodialysis patients

Background

Simkania negevensis is an obligate intracellular bacterium belonging to the family Simkaniaceae in the Chlamydiales order. It is considered an ubiquitous microorganism and aquatic environments may be involved as a source of infection for humans. It was just isolated in samples from domestic water supplies and from mains water supplies, like spa water or swimming pool water, confirming its ability to resist to the common chlorination treatments. Evidence indicates a possible role of the microorganism in respiratory tract infections, in gastroenteric disorders and in the pathogenesis of cardiovascular disease, furthermore it has hypothesized that it could play a role in lung transplant rejection. Prevalence and possible effects in nephrology are unknown.

Methods

We examined the occurrence of Simkania negevensis in two differents populations, both characterized by a high susceptibility to infectious complications: 105 hemodialysis patients, 105 renal transplant recipients and 105 healthy subjects through the IgG and IgA response to Simkania negevensis in their sera. Serum antibodies to Simkania negevensis were detected by a homemade ELISA performed according to the Kahane’s protocol. Furthermore water samples from hemodialytic circuit were collected, to evaluate Simkania negevensis resistance to usual treatment of disinfection.

Results

Our results were unexpected, showing a higher seroprevalence of antibodies against Simkania negevensis in the hemodialysis patients, compared to renal transplant patients (IgG 22% vs 9% - IgA 9% vs 3%). S. negevensis was isolated in all water samples analyzed.

Conclusions

Our study detected for the first time the occurrence of S. negevensis in hemodialysis and in renal transplant patients. Our findings suggest that water used in hemodialysis could be one of the possible sources of S. negevensis infection, without clinical involvement risk for patients.

Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order

Simkania negevensis is a Chlamydia-related bacterium discovered in 1993 and represents the founding member of the Simkaniaceae family within the Chlamydiales order. As other Chlamydiales, it is an obligate intracellular bacterium characterized by a biphasic developmental cycle. Its similarities with the pathogenic Chlamydia trachomatis and Chlamydia pneumoniae make it an interesting bacterium. So far, little is known about its biology, but S. negevensis harbors various microbiological characteristics of interest, including a strong association of the Simkania-containing vacuole with the ER and the presence of an intron in the 23S rRNA encoding gene. Evidence of human exposition has been reported worldwide. However, there is a lack of robust clinical studies evaluating its implication in human diseases; current data suggest an association with pneumonia and bronchiolitis making S. negevensis a potential emerging pathogen. Owing to its fastidious growth requirements, the clinical relevance of S. negevensis is probably underestimated. In this review, we summarize the current knowledge on S. negevensis and explore future research challenges.

Environmental (Saprozoic) Pathogens of Engineered Water Systems: Understanding Their Ecology for Risk Assessment and Management

Major waterborne (enteric) pathogens are relatively well understood and treatment controls are effective when well managed. However, water-based, saprozoic pathogens that grow within engineered water systems (primarily within biofilms/sediments) cannot be controlled by water treatment alone prior to entry into water distribution and other engineered water systems. Growth within biofilms or as in the case of Legionella pneumophila, primarily within free-living protozoa feeding on biofilms, results from competitive advantage. Meaning, to understand how to manage water-based pathogen diseases (a sub-set of saprozoses) we need to understand the microbial ecology of biofilms; with key factors including biofilm bacterial diversity that influence amoebae hosts and members antagonistic to water-based pathogens, along with impacts from biofilm substratum, water temperature, flow conditions and disinfectant residual—all control variables. Major saprozoic pathogens covering viruses, bacteria, fungi and free-living protozoa are listed, yet today most of the recognized health burden from drinking waters is driven by legionellae, non-tuberculous mycobacteria (NTM) and, to a lesser extent, Pseudomonas aeruginosa. In developing best management practices for engineered water systems based on hazard analysis critical control point (HACCP) or water safety plan (WSP) approaches, multi-factor control strategies, based on quantitative microbial risk assessments need to be developed, to reduce disease from largely opportunistic, water-based pathogens.