ABSTRACT
Streptococcus mitis is a leading cause of infective endocarditis (IE). However, our understanding of the genomic epidemiology and pathogenicity of IE-associated S. mitis is hampered by low IE incidence. Here we use whole genome sequencing of 129 S. mitis bloodstream infection (BSI) isolates collected between 2001-2016 from clinically diagnosed IE cases in the UK to investigate genetic diversity, antimicrobial resistance, and pathogenicity. We show high genetic diversity of IE-associated S. mitis with virtually all isolates belonging to distinct lineages indicating no predominance of specific lineages. Additionally, we find a highly variable distribution of known pneumococcal virulence genes among the isolates, some of which are overrepresented in disease when compared to carriage strains. Our findings suggest that S. mitis in patients with clinically diagnosed IE is not primarily caused by specific hypervirulent or antimicrobial resistant lineages, highlighting the accidental pathogenic nature of S. mitis in patients with clinically diagnosed IE.
Subject(s)
Bacteremia , Streptococcal Infections , Streptococcus mitis , Humans , Streptococcus mitis/genetics , Streptococcus mitis/isolation & purification , United Kingdom/epidemiology , Streptococcal Infections/microbiology , Streptococcal Infections/epidemiology , Ireland/epidemiology , Bacteremia/microbiology , Bacteremia/epidemiology , Endocarditis/microbiology , Endocarditis/epidemiology , Genome, Bacterial/genetics , Whole Genome Sequencing , Male , Female , Genetic Variation , Genomics , Aged , Phylogeny , Middle Aged , Drug Resistance, Bacterial/genetics , Endocarditis, Bacterial/microbiology , Endocarditis, Bacterial/epidemiology , Adult , Virulence Factors/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Virulence/geneticsABSTRACT
Asthma is a significant public health concern, particularly in children with severe symptoms. Exacerbation of asthma (EOA) is life-threatening, and respiratory infections (RIs) play a crucial role. Though viruses play a significant role in EOA, patients are empirically treated with antibiotics, contributing to antibiotic resistance development. Although there are widely reported associations of EOA with viral or Mycoplasma pneumoniae infections, there are no published data for Sri Lanka. The present study aimed to identify the association of common respiratory viruses, typical respiratory bacterial pathogens and M. pneumoniae in children with EOA and relate them with the compatibility of antimicrobial use. A case-control study was conducted in the paediatric unit of North Colombo Teaching Hospital, Sri Lanka, involving two groups of children between 5 and 15 years of age. Group 1 is children with EOA and Group 2 is children with stable asthma (SA). Each group consisted of 100 children. Sputum/throat swabs were tested for common respiratory viruses using virus-specific fluorescein isothiocyanate-labelled monoclonal antibodies (MAbs), bacteria by routine culture, and M. pneumoniae by real-time polymerase chain reaction. Macrolide resistance in M. pneumoniae was detected using conventional PCR and sequencing specific genetic mutations in the 23S rRNA gene. M. pneumoniae was genotyped using nested multilocus sequence typing, which targeted eight housekeeping genes (ppa, pgm, gyrB, gmk, glyA, atpA, arcC and adk). There was no significant difference in age, gender, demographic or geographical location between the two groups. In children with EOA, antibiotics were used in 66â% (66/100) and macrolides in 42â% (42/100). Samples comprised 78â% (78/100) sputum and 22â% (22/100) throat swabs. Adenovirus was the most common virus identified, and it was significantly higher in children with EOA compared to those with SA. Still, the two groups had no significant difference in typical bacteria findings. M. pneumoniae was detected in one patient with EOA, but none was detected in the SA group. The M. pneumoniae was macrolide-sensitive and ST14 by multilocus sequence typing. This study showed that the empiric use of antibiotics in children with asthma might be better targeted with prior pathogen screening to inform appropriate treatment to minimize antibiotic resistance.
ABSTRACT
Streptococcus suis, a zoonotic bacterial pathogen circulated through swine, can cause severe infections in humans. Because human S. suis infections are not notifiable in most countries, incidence is underestimated. We aimed to increase insight into the molecular epidemiology of human S. suis infections in Europe. To procure data, we surveyed 7 reference laboratories and performed a systematic review of the scientific literature. We identified 236 cases of human S. suis infection from those sources and an additional 87 by scanning gray literature. We performed whole-genome sequencing to type 46 zoonotic S. suis isolates and combined them with 28 publicly available genomes in a core-genome phylogeny. Clonal complex (CC) 1 isolates accounted for 87% of typed human infections; CC20, CC25, CC87, and CC94 also caused infections. Emergence of diverse zoonotic clades and notable severity of illness in humans support classifying S. suis infection as a notifiable condition.
Subject(s)
Molecular Epidemiology , Phylogeny , Streptococcal Infections , Streptococcus suis , Zoonoses , Streptococcus suis/genetics , Streptococcus suis/classification , Streptococcal Infections/epidemiology , Streptococcal Infections/microbiology , Streptococcal Infections/veterinary , Europe/epidemiology , Humans , Animals , Zoonoses/epidemiology , Swine , Whole Genome Sequencing , Communicable Diseases, Emerging/epidemiology , Communicable Diseases, Emerging/microbiology , Bacterial Zoonoses/epidemiology , Bacterial Zoonoses/microbiology , Swine Diseases/epidemiology , Swine Diseases/microbiologyABSTRACT
INTRODUCTION: Antimicrobial resistance (AMR) is a global threat that necessitates coordinated strategies to improve antibiotic prescribing and reduce AMR. A key activity is ascertaining current prescribing patterns in hospitals to identify targets for quality improvement programmes. METHODS: The World Health Organisation point prevalence survey methodology was used to assess antibiotic prescribing in the Cape Coast Teaching Hospital. All core variables identified by the methodology were recorded. RESULTS: A total of 78.8% (82/104) patients were prescribed at least one antibiotic, with the majority from adult surgical wards (52.14%). Significantly longer hospital stays were associated with patients who underwent surgery (p = 0.0423). "Access" antibiotics dominated total prescriptions (63.8%, 132/207) with ceftriaxone, cefuroxime, and ciprofloxacin being the most prescribed "Watch" antibiotics. The most common indications were for medical prophylaxis (59.8%, 49/82) and surgical prophylaxis (46.3%, 38/82). Over one-third of surgical prophylaxis (34.2%, 13/38) indications extended beyond one day. There was moderate documentation of reasons for antibiotic treatment in patient notes (65.9%, 54/82), and targeted therapy after samples were taken for antimicrobial susceptibility testing (41.7%, 10/24). Guideline compliance was low (25%) where available. CONCLUSIONS: There was high use of antibiotics within the hospital which needs addressing. Identified quality targets include developing surgical prophylaxis guidelines, reviewing "Watch" antibiotic prescribing, and assessing antibiotic durations for patients on two or more antibiotics. Organizational-level deficiencies were also identified that need addressing to help instigate ASPs. These can be addressed by developing local prescribing protocols and antibiotic stewardship policies in this hospital and wider in Ghana and across Africa.
Subject(s)
Anti-Bacterial Agents , Antimicrobial Stewardship , Adult , Humans , Anti-Bacterial Agents/therapeutic use , Ghana/epidemiology , Prevalence , Surveys and Questionnaires , Hospitals, Teaching , Drug PrescriptionsABSTRACT
Streptococcus agalactiae or group B streptococcus (GBS) is a leading cause of neonatal sepsis and increasingly found as an invasive pathogen in older patient populations. Beta-lactam antibiotics remain the most effective therapeutic with resistance rarely reported, while the majority of GBS isolates carry the tetracycline resistance gene tet(M) in fixed genomic positions amongst five predominant clonal clades. In the UK, GBS resistance to clindamycin and erythromycin has increased from 3% in 1991 to 11.9% (clindamycin) and 20.2% (erythromycin), as reported in this study. Here, a systematic investigation of antimicrobial resistance genomic content sought to fully characterise the associated mobile genetic elements within phenotypically resistant GBS isolates from 193 invasive and non-invasive infections of UK adult patients collected during 2014 and 2015. Resistance to erythromycin and clindamycin was mediated by erm(A) (16/193, 8.2%), erm(B) (16/193, 8.2%), mef(A)/msr(D) (10/193, 5.1%), lsa(C) (3/193, 1.5%), lnu(C) (1/193, 0.5%), and erm(T) (1/193, 0.5%) genes. The integrative conjugative elements (ICEs) carrying these genes were occasionally found in combination with high gentamicin resistance mediating genes aac(6')-aph(2â³), aminoglycoside resistance genes (ant(6-Ia), aph(3'-III), and/or aad(E)), alternative tetracycline resistance genes (tet(O) and tet(S)), and/or chloramphenicol resistance gene cat(Q), mediating resistance to multiple classes of antibiotics. This study provides evidence of the retention of previously reported ICESag37 (n = 4), ICESag236 (n = 2), and ICESpy009 (n = 3), as well as the definition of sixteen novel ICEs and three novel transposons within the GBS lineage, with no evidence of horizontal transfer.
ABSTRACT
BACKGROUND: Antimicrobial resistance (AMR) is a major public health challenge with its impact felt disproportionately in Western Sub-Saharan Africa. Routine microbiology investigations serve as a rich source of AMR monitoring and surveillance data. Geographical variations in susceptibility patterns necessitate regional and institutional tracking of resistance patterns to aid in tailored Antimicrobial Stewardship (AMS) interventions to improve antibiotic use in such settings. This study focused on developing a cumulative antibiogram of bacterial isolates from clinical samples at the Cape Coast Teaching Hospital (CCTH). This was ultimately to improve AMS by guiding empiric therapy. METHODS: A hospital-based longitudinal study involving standard microbiological procedures was conducted from 1st January to 31st December 2020. Isolates from routine diagnostic aerobic cultures were identified by colony morphology, Gram staining, and conventional biochemical tests. Isolates were subjected to antibiotic susceptibility testing using Kirby-Bauer disc diffusion. Inhibitory zone diameters were interpreted per the Clinical and Laboratory Standards Institute guidelines and were entered and analysed on the WHONET software using the "first isolate only" principle. RESULTS: Overall, low to moderate susceptibility was observed in most pathogen-antibiotic combinations analysed in the study. Amikacin showed the highest susceptibility (86%, n = 537/626) against all Gram-negatives with ampicillin exhibiting the lowest (6%, n = 27/480). Among the Gram-positives, the highest susceptibilities were exhibited by gentamicin (78%, n = 124/159), with clindamycin having the lowest susceptibility (27%, n = 41/154). Among the Gram-negatives, 66% (n = 426/648) of the isolates were identified phenotypically as potential extended-spectrum beta-lactamase producers. Multiple multidrug-resistant isolates were also identified among both Gram-positive and Gram-negative isolates. Low to moderate susceptibility was found against first- and second-line antibiotics recommended in the National standard treatment guidelines (NSTG). Laboratory quality management deficiencies and a turnaround time of 3.4 days were the major AMS barriers identified. CONCLUSIONS: Low to moderate susceptibilities coupled with high rates of phenotypic resistance warrant tailoring NSTGs to fit local contexts within CCTH even after considering the biases in these results. The cumulative antibiogram proved a key AMS programme component after its communication to clinicians and subsequent monitoring of its influence on prescribing indicators. This should be adopted to enhance such programmes across the country.
Subject(s)
Antimicrobial Stewardship , Amikacin , Ampicillin , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Clindamycin , Gentamicins , Ghana/epidemiology , Hospitals, Teaching , Humans , Longitudinal Studies , Microbial Sensitivity Tests , beta-LactamasesABSTRACT
OBJECTIVES: To determine the phenotypic and genotypic antibiotic susceptibility of Mycoplasma amphoriforme isolates recovered from patients in the UK and Denmark. METHODS: Seven isolates of M. amphoriforme were examined for antimicrobial susceptibility to seven antibiotics using the microbroth dilution assay in line with the CLSI guidelines for mycoplasmas. Each isolate was additionally subjected to WGS to identify resistance-associated mutations. Based on the consensus sequences from the genomic data, PCR primers were designed, and tested, for the amplification of the QRDR within the parC gene. RESULTS: Of the seven isolates investigated, four (57%) were resistant to moxifloxacin (0.5-1â mg/L) and levofloxacin (1-2â mg/L), compared with those that were susceptible (0.03-0.06 and 0.006â mg/L, respectively). Isolate H29 was resistant to five of the seven antibiotics tested: moxifloxacin, 0.5â mg/L; levofloxacin, 2â mg/L; azithromycin, 64â mg/L; erythromycin, 128â mg/L; and clindamycin, 64â mg/L. All isolates were susceptible to tetracycline (0.06â mg/L) and lefamulin (0.001-0.004â mg/L). Mutations from genomic data confirmed the presence of an S89F mutation within the ParC protein among all fluoroquinolone-resistant isolates and an A2059G mutation in the 23S rRNA gene in the macrolide- and lincosamide-resistant isolate H29. CONCLUSIONS: To the best of our knowledge, this is the first time where phenotypic and genotypic resistance data have been paired for M. amphoriforme confirming a correlation between the two. These data suggest the need for focused testing and resistance determination of isolates from high-risk patients given the backdrop of a high prevalence of antimicrobial resistance.
Subject(s)
Anti-Bacterial Agents , Levofloxacin , Humans , Moxifloxacin , Microbial Sensitivity Tests , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Denmark , United Kingdom , Drug Resistance, BacterialABSTRACT
BackgroundMycoplasma pneumoniae respiratory infections are transmitted by aerosol and droplets in close contact.AimWe investigated global M. pneumoniae incidence after implementation of non-pharmaceutical interventions (NPIs) against COVID-19 in March 2020.MethodsWe surveyed M. pneumoniae detections from laboratories and surveillance systems (national or regional) across the world from 1 April 2020 to 31 March 2021 and compared them with cases from corresponding months between 2017 and 2020. Macrolide-resistant M. pneumoniae (MRMp) data were collected from 1 April 2017 to 31 March 2021.ResultsThirty-seven sites from 21 countries in Europe, Asia, America and Oceania submitted valid datasets (631,104 tests). Among the 30,617 M. pneumoniae detections, 62.39% were based on direct test methods (predominantly PCR), 34.24% on a combination of PCR and serology (no distinction between methods) and 3.37% on serology alone (only IgM considered). In all countries, M. pneumoniae incidence by direct test methods declined significantly after implementation of NPIs with a mean of 1.69% (SD ± 3.30) compared with 8.61% (SD ± 10.62) in previous years (p < 0.01). Detection rates decreased with direct but not with indirect test methods (serology) (-93.51% vs + 18.08%; p < 0.01). Direct detections remained low worldwide throughout April 2020 to March 2021 despite widely differing lockdown or school closure periods. Seven sites (Europe, Asia and America) reported MRMp detections in one of 22 investigated cases in April 2020 to March 2021 and 176 of 762 (23.10%) in previous years (p = 0.04).ConclusionsThis comprehensive collection of M. pneumoniae detections worldwide shows correlation between COVID-19 NPIs and significantly reduced detection numbers.
Subject(s)
COVID-19 , Pneumonia, Mycoplasma , COVID-19/epidemiology , Communicable Disease Control , Humans , Macrolides , Mycoplasma pneumoniae/genetics , Pandemics , Pneumonia, Mycoplasma/diagnosis , Pneumonia, Mycoplasma/epidemiologyABSTRACT
Cases of invasive group B streptococcal infection in the adult UK population have steadily increased over recent years, with the most common serotypes being V, III and Ia, but less is known of the genetic background of these strains. We have carried out in-depth analysis of the whole-genome sequences of 193 clinically important group B Streptococcus (GBS) isolates (184 were from invasive infection, 8 were from non-invasive infection and 1 had no information on isolation site) isolated from adults and submitted to the National Reference Laboratory at the UK Health Security Agency between January 2014 and December 2015. We have determined that capsular serotypes III (26.9%), Ia (26.4%) and V (15.0%) were most commonly identified, with slight differences in gender and age distribution. Most isolates (n=182) grouped to five clonal complexes (CCs), CC1, CC8/CC10, CC17, CC19 and CC23, with common associations between specific serotypes and virulence genes. Additionally, we have identified large recombination events mediating potential capsular switching events between sequence type (ST)1 serotype V and serotypes Ib (n=2 isolates), II (n=2 isolates) and VI (n=2 isolates); between ST19 serotype III and serotype V (n=5 isolates); and between CC17 serotype III and serotype IV (n=1 isolate). The high genetic diversity of disease-causing isolates and multiple recombination events reported in this study highlight the need for routine surveillance of the circulating disease-causing GBS strains. This information is crucial to better understand the global spread of GBS serotypes and genotypes, and will form the baseline information for any future GBS vaccine research in the UK and worldwide.
Subject(s)
Streptococcal Infections , Streptococcus agalactiae , Adult , Humans , Multilocus Sequence Typing , Recombination, Genetic , Streptococcal Infections/epidemiology , Streptococcus agalactiae/genetics , United Kingdom/epidemiologyABSTRACT
BACKGROUND: The burden of antibiotic resistant infection is mainly felt in low-to-middle income countries, where the rate of antimicrobial resistance is largely under-surveyed and under huge pressure from unregulated, disparate and often self-guided access to antimicrobials. Nosocomial infections from hospital environments have been shown to be a particularly prevalent source of multi-drug resistant strains, yet surveillance of hospital environmental contamination is often not investigated. METHODS: The study was prospective, observational and cross-sectional, sampling 231 high and low touch surfaces from 15th March to 13th April 2021, from five wards in the Cape Coast Teaching Hospital, Ghana. Microbial growth in the presence of vancomycin and either meropenem or cefotaxime was examined and bacterial species were identified by MALDI-TOF. The presence of common extended-spectrum ß-lactamases (ESBL) and carbapenemase antimicrobial resistance genes (ARG) were identified through PCR screening, which were confirmed by phenotypic antimicrobial susceptibility determination. Isolates positive for carbapenem resistance genes were sequenced using a multi-platform approach. RESULTS: We recovered microbial growth from 99% of swabs (n = 229/231) plated on agar in the absence of antimicrobials. Multiple sites were found to be colonised with resistant bacteria throughout the hospital setting. Bacteria with multi-drug resistance and ARG of concern were isolated from high and low touch points with evidence of strain dissemination throughout the environment. A total of 21 differing species of bacteria carrying ARG were isolated. The high prevalence of Acinetobacter baumannii carrying blaNDM-1 observed was further characterised by whole genome sequencing and phylogenetic analysis to determine the relationship between resistant strains found in different wards. CONCLUSION: Evidence of multiple clonal incursions of MDR bacteria of high sepsis risk were found in two separate wards for a regional hospital in Ghana. The prevalence of multiple blaNDM carrying species in combination with combinations of ESBLs was particularly concerning and unexpected in Africa. We also identify strains carrying tet(X3), blaVIM-5 or blaDIM-1 showing a high diversity of carbapenamases present as a reservoir in a hospital setting. Findings of multi-drug resistant bacteria from multiple environmental sites throughout the hospital will inform future IPC practices and aid research prioritisation for AMR in Ghana.
Subject(s)
Anti-Bacterial Agents , Gram-Negative Bacteria , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Bacterial Proteins , Cross-Sectional Studies , Environmental Monitoring , Ghana/epidemiology , Gram-Negative Bacteria/genetics , Humans , Microbial Sensitivity Tests , Phylogeny , Prospective Studies , Tertiary Care Centers , beta-LactamasesSubject(s)
COVID-19 , Coinfection , Critical Care , Hospitals , Humans , Intensive Care Units , Length of Stay , Retrospective Studies , State MedicineABSTRACT
Both Legionella pneumophila and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause pneumonia. L. pneumophila is acquired from water sources, sometimes in healthcare settings. We report 2 fatal cases of L. pneumophila and SARS-CoV-2 co-infection in England. Clinicians should be aware of possible L. pneumophila infections among SARS-CoV-2 patients.
Subject(s)
COVID-19 , Coinfection , Legionella pneumophila , Legionnaires' Disease , Humans , Legionnaires' Disease/diagnosis , SARS-CoV-2ABSTRACT
Group B Streptococcus (GBS) is a leading cause of neonatal meningitis, pneumonia, and sepsis. The biggest contributing factor of neonatal infections is due to vertical transmission from maternal colonisation of GBS in the genitourinary tract. Multiple serotype colonisation is often not investigated in epidemiological studies, but it is an important consideration for serotype-based vaccine development and implementation to ensure less abundant serotypes are not under-represented. In this study, we show that RAPD PCR is a quick tool useful in screening the presence of genetically different strains using multiple colony picks from a single patient swab. We observed a maximum of five different GBS strains colonising a single patient at a specific time.
Subject(s)
Mass Screening/methods , Polymerase Chain Reaction/methods , Random Amplified Polymorphic DNA Technique/methods , Streptococcus agalactiae/genetics , Streptococcus agalactiae/isolation & purification , DNA, Bacterial , Female , Humans , Infant , Milk, Human/microbiology , Nasopharynx/microbiology , Polymorphism, Single Nucleotide , Rectum/microbiology , Serogroup , Streptococcal Infections/diagnosis , Streptococcal Infections/microbiology , Vagina/microbiology , Whole Genome SequencingABSTRACT
Group B Streptococcus (GBS) is a common intestinal colonizer during the neonatal period, but also may cause late-onset sepsis or meningitis in up to 0.5% of otherwise healthy colonized infants after day 3 of life. Transmission routes and risk factors of this late-onset form of invasive GBS disease (iGBS) are not fully understood. Cases of iGBS with recurrence (n=25) and those occurring in parallel in twins/triplets (n=32) from the UK and Ireland (national surveillance study 2014/15) and from Germany and Switzerland (retrospective case collection) were analyzed to unravel shared (in affected multiples) or fixed (in recurrent disease) risk factors for GBS disease. The risk of iGBS among infants from multiple births was high (17%), if one infant had already developed GBS disease. The interval of onset of iGBS between siblings was 4.5 days and in recurrent cases 12.5 days. Disturbances of the individual microbiome, including persistence of infectious foci are suggested e.g. by high usage of perinatal antibiotics in mothers of affected multiples, and by the association of an increased risk of recurrence with a short term of antibiotics [aOR 4.2 (1.3-14.2), P=0.02]. Identical GBS serotypes in both recurrent infections and concurrently infected multiples might indicate a failed microbiome integration of GBS strains that are generally regarded as commensals in healthy infants. The dynamics of recurrent GBS infections or concurrent infections in multiples suggest individual patterns of exposure and fluctuations in host immunity, causing failure of natural niche occupation.
Subject(s)
Anti-Bacterial Agents/adverse effects , Drug-Related Side Effects and Adverse Reactions/epidemiology , Dysbiosis/epidemiology , Sepsis/epidemiology , Streptococcal Infections/epidemiology , Streptococcus/physiology , Age of Onset , Anti-Bacterial Agents/therapeutic use , Dysbiosis/etiology , Europe/epidemiology , Female , Humans , Infant, Newborn , Male , Microbiota , Pregnancy , Pregnancy Complications, Infectious , Recurrence , Retrospective Studies , Risk Factors , Triplets , TwinsABSTRACT
OBJECTIVES: To determine the presence and genotypic macrolide susceptibility of Mycoplasma amphoriforme, and the presence of Ureaplasma spp. and Mycoplasma fermentans among clinical samples from England previously investigated for Mycoplasma pneumoniae. METHODS: Quantitative and conventional PCR methods were used to retrospectively screen a collection of 160 clinical samples previously submitted to Public Health England (PHE) for the detection of M. pneumoniae between October 2016 and December 2017. Samples which were positive for M. amphoriforme DNA were further investigated for mutations associated with genotypic macrolide resistance by sequencing domain V of the 23s rRNA. RESULTS: M. amphoriforme was detected in 10/160 samples (6.3%), Ureaplasma parvum was detected in 4/160 samples (2.5%), and M. fermentans was not detected in any samples (0/160). Of the nine individuals (two samples were from the same patient) in which M. amphoriforme was detected, eight were male (age range 10-60 years) and one was female (age range 30-40 years). One individual with cystic fibrosis was positive for both M. amphoriforme and U. parvum. All M. amphoriforme DNA was genotypically susceptible to macrolides. CONCLUSIONS: Mycoplasma amphoriforme was found in clinical samples, including lower respiratory tract samples of patients with pneumonia. In the absence of other respiratory pathogens, these data suggest a potential role for this organism in human disease, with no evidence of acquired macrolide resistance. Ureaplasma parvum was detected in cerebrospinal fluid and respiratory tract samples. These data suggest that there is a need to consider these atypical respiratory pathogens in future diagnostic investigations.
Subject(s)
Mycoplasma Infections , Mycoplasma fermentans , Mycoplasma/isolation & purification , Ureaplasma/isolation & purification , Adolescent , Adult , Anti-Bacterial Agents/pharmacology , Child , Drug Resistance, Bacterial/genetics , Female , Humans , Macrolides/pharmacology , Male , Middle Aged , Mycoplasma/drug effects , Mycoplasma/genetics , Mycoplasma Infections/epidemiology , Mycoplasma fermentans/drug effects , Mycoplasma fermentans/genetics , Mycoplasma fermentans/isolation & purification , Retrospective Studies , Ureaplasma/drug effects , Ureaplasma/genetics , Young AdultABSTRACT
Legionella pneumophila, a Gram-negative bacillus, is the causative agent of Legionnaire's disease, a form of severe community-acquired pneumonia. Infection can have high morbidity, with a high proportion of patients requiring ICU admission, and up to 10% mortality, which is exacerbated by the lack of efficacy of typical empirical antibiotic therapy against Legionella spp. The fastidious nature of the entire Legionellaceae family historically required inclusion of activated charcoal in the solid medium to remove growth inhibitors, which inherently interferes with accurate antimicrobial susceptibility determination, an acknowledged methodological shortfall, now rectified by a new solid medium that gives results comparable to those of microbroth dilution. Here, as an international Legionella community (with authors representing various international reference laboratories, countries and clinical stakeholders for diagnosis and treatment of legionellosis), we set out recommendations for the standardization of antimicrobial susceptibility testing methods, guidelines and reference strains to facilitate an improved era of antibiotic resistance determination.
Subject(s)
Legionella pneumophila , Legionella , Legionnaires' Disease , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Humans , Legionnaires' Disease/diagnosis , Legionnaires' Disease/drug therapy , Reference StandardsABSTRACT
A minimal genome and absent bacterial cell wall render Mycoplasma hominis inherently resistant to most antimicrobials except lincosamides, tetracyclines, and fluoroquinolones. Often dismissed as a commensal (except where linked to preterm birth), it causes septic arthritis in immunodeficient patients and is increasingly associated with transplant failure (particularly lung) accompanying immunosuppression. We examined antimicrobial susceptibility (AST) on strains archived from 2005 to 2015 submitted to the Public Health England reference laboratory and determined the underlying mechanism of resistance by whole-genome sequencing (WGS). Archived M. hominis strains included 32/115 from invasive infection (sepsis, cerebrospinal [CSF], peritoneal, and pleural fluid) over the 10-year period (6.4% of all samples submitted from 2010 to 2015 were positive). No clindamycin resistance was detected, while two strains were resistant to moxifloxacin and levofloxacin (resistance mutations S83L or E87G in gyrA and S81I or E84V in parC). One of these strains and 11 additional strains were tetracycline resistant, mediated by tet(M) carried within an integrative conjugative element (ICE) consistently integrated at the somatic rumA gene; however, the ICEs varied widely in 5 to 19 associated accessory genes. WGS analysis showed that tet(M)-carrying strains were not clonal, refuting previous speculation that the ICE was broken and immobile. We found tet(M)-positive and -negative strains (including the multiresistant 2015 strain) to be equally susceptible to tigecycline and josamycin; however, the British National Formulary does not include guidance for these. Continued M. hominis investigation and AST surveillance (especially immunocompromised patients) is warranted, and the limited number of therapeutics needs to be expanded in the United Kingdom.
Subject(s)
Mycoplasma Infections , Premature Birth , Anti-Bacterial Agents/pharmacology , England , Female , Humans , Infant, Newborn , Microbial Sensitivity Tests , Mycoplasma Infections/drug therapy , Mycoplasma hominis/genetics , Pregnancy , Tetracycline Resistance/genetics , United KingdomABSTRACT
BACKGROUND: The true frequency of hospital outbreaks of invasive group B streptococcal (iGBS; Streptococcus agalactiae) disease in infants is unknown. We used whole genome sequencing (WGS) of iGBS isolates collected during a period of enhanced surveillance of infant iGBS disease in the UK and Ireland to determine the number of clustered cases. METHODS: Potentially linked iGBS cases from infants with early (<7 days of life) or late-onset (7-89 days) disease were identified from WGS data (HiSeq 2500 platform, Illumina) from clinical sterile site isolates collected between 04/2014 and 04/2015. We assessed time and place of cases to determine a single-nucleotide polymorphism (SNP) difference threshold for clustered cases. Case details were augmented through linkage to national hospital admission data and hospital record review by local microbiologists. RESULTS: Analysis of sequences indicated a cutoff of ≤5 SNP differences to define iGBS clusters. Among 410 infant iGBS isolates, we identified 7 clusters (4 genetically identical pairs with 0 SNP differences, 1 pair with 3 SNP differences, 1 cluster of 4 cases with ≤1 SNP differences) of which 4 clusters were uncovered for the first time. The clusters comprised 16 cases, of which 15 were late-onset (of 192 late-onset cases with sequenced isolates) and 1 an early-onset index case. Serial intervals between cases ranged from 0 to 59 (median 12) days. CONCLUSIONS: Approximately 1 in 12 late-onset infant iGBS cases were part of a hospital cluster. Over half of the clusters were previously undetected, emphasizing the importance of routine submission of iGBS isolates to reference laboratories for cluster identification and genomic confirmation.
Subject(s)
Streptococcal Infections , Streptococcus agalactiae , Disease Hotspot , Epidemiologic Studies , Genomics , Humans , Infant , Ireland/epidemiology , Streptococcal Infections/epidemiology , Streptococcus agalactiae/genetics , United Kingdom/epidemiologyABSTRACT
OBJECTIVES: There is a lack of international unification for AST methodology for Legionella pneumophila. Current literature contains multiple possible methods and this study compares each of them to determine methodological concordance. METHODS: Antibiotic susceptibility of 50 L. pneumophila strains was determined using broth microdilution (BMD), serial antimicrobial dilution in traditional buffered charcoal yeast extract (BCYE) agar (as well as comparison with gradient strip overlay on BCYE) and in a novel charcoal-free agar (LASARUS) for rifampicin, azithromycin, levofloxacin and doxycycline. RESULTS: The deviation of tested media relative to BMD highlighted the overall similarity of BMD and LASARUS across all antimicrobials tested (within one serial dilution). BCYE agar dilution showed an increased MIC of up to five serial dilutions relative to BMD, while MICs by gradient strip overlay on BCYE were elevated by two to three serial dilutions, with the exception of doxycycline, which was decreased by three serial dilutions relative to MIC values determined by BMD. The MIC range for azithromycin was wider than for other antimicrobials tested and found to be caused by the presence or absence of the lpeAB gene. CONCLUSIONS: BMD-based antimicrobial susceptibility testing (AST) methodology should be the internationally agreed gold standard for Legionella spp. AST, as is common for other bacterial species. Traditional BCYE gave significantly elevated MIC results and its use should be discontinued for Legionella spp., while MIC determination using LASARUS solid medium gave results concordant (within one serial dilution) with BMD for all antimicrobials tested. To the best of our knowledge, this study is the first to identify the lpeAB gene in UK isolates.