Management of an outbreak of postpartum Streptococcus pyogenes emm75 infections.

BACKGROUND: Streptococcus pyogenes is a well-known cause of postpartum infections and is causing significant morbidity and mortality. AIM: To describe measures taken to control an outbreak of postpartum infections caused by S. pyogenes emm75 on a maternity ward. METHODS: Patients presenting postpartum with signs and symptoms of infection were cultured for ß-haemolytic streptococci with cervical swabs and blood cultures, and bacterial isolates were species-determined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and emm-typed. Pharyngeal swabs were taken from healthcare workers (HCWs) at the ward. Bacterial isolates were subjected to whole-genome sequencing (WGS). The multi-locus sequence type and the number of single nucleotide polymorphisms (SNPs) compared to an index genome were determined. FINDINGS: During a three-month period, six cases of postpartum infection with S. pyogenes emm75 were identified on the maternity ward. By comparing delivery dates with duty rotas, one HCW was identified as a possible source of infection in five cases. After repeated pharyngeal swabs from this individual, an S. pyogenes emm75 was isolated. The five isolates from patients epidemiologically linked to the HCW and the two isolates of the family members had an identical sequence type (ST49) and 0-2 SNPs difference compared to the HCW isolate, whereas the sixth patient had an unrelated isolate. Eradication antibiotic therapy with clindamycin and rifampicin was given to the carrier. All patients received intravenous antibiotic treatment and recovered. CONCLUSION: A three-month outbreak was stopped when a carrier was identified and treated. Source identification and WGS proved vital for outbreak control.

Clinical and microbiological features of bacteraemia with Gram-positive anaerobic cocci: a population-based retrospective study.

OBJECTIVES: Gram-positive, anaerobic cocci (GPAC) can cause infections in humans. Only a few cases of bacteraemia with GPAC have been reported. We describe the clinical and microbiological characteristics of GPAC bacteraemia. METHODS: A retrospective population-based study of GPAC bacteraemia 2012-2016 in southern Sweden was performed. GPAC were identified using matrix-associated laser desorption ionization time-of-flight mass spectrometry or 16S rRNA gene sequencing. Etests were used to determine antibiotic susceptibilities. Data on patient and infection characteristics, treatment, and outcome were collected from the medical records. RESULTS: A total of 226 episodes of GPAC bacteraemia in adults were studied; this corresponds to an annual incidence of 3.4 cases per 100,000 persons per year. The bacteria identified were Anaerococcus spp. (n = 43), Atopobium spp. (n = 7), Blautia spp. (n = 1), Finegoldia spp. (n = 15), Parvimonas spp. (n = 100), Peptoniphilus spp. (n = 52), Peptostreptococcus spp. (n = 2), and Ruminococcus spp. (n = 9) of which 200 isolates were identified to the species level. Resistance to imipenem and piperacillin was not identified, whereas resistance among the 229 isolates to penicillin was detected in four, to metronidazole in six, and clindamycin in 16 isolates. The median age of patients was 73 years (55-83, IQR), 57% were male and comorbidities were common. Fifty-one per cent of infections were polymicrobial. In 60% of cases a focus of infection was identified. Forty per cent of patients had either organ dysfunction or shock. The 30-day mortality was 11%, and nosocomial infections were over-represented among the deceased. CONCLUSIONS: GPAC bacteraemia is much more common than previously reported. GPAC-bacteraemia is a condition with significant mortality mainly affecting elderly persons with comorbidities.

Clinical and microbiological features of Actinotignum bacteremia: a retrospective observational study of 57 cases.

The purpose of this study was to investigate the incidence, clinical presentation, and prognosis of Actinotignum bacteremia in southern Sweden. Actinotignum isolates in blood cultures were identified retrospectively between 1st January 2012 and 31st March 2016 through searches in the clinical microbiology laboratory database. The population covered by this laboratory is approximately 1.3 million. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for species determination. Etests were used for minimum inhibitory concentration (MIC) determination. The patients' medical charts were reviewed. Fifty-eight episodes in fifty-seven patients with Actinotignum bacteremia were identified (A. schaalii = 53, A. sanguinis = 1, A. urinale = 2, and Actinotignum species = 3), which corresponds to an incidence of 11 cases per million inhabitants. Fifty-one percent of the isolates were in pure culture. The MICs were low for ß-lactam antibiotics, whereas high MICs were recorded for ciprofloxacin and trimethoprim. Patients had a median age of 82 years, 72% were male, and a majority had underlying urological conditions. Thirty-six of the patients were diagnosed with a focus from the urinary tract. Thirty-one patients developed severe sepsis and nine patients died during the hospital stay. Our study is the largest of Actinotignum bacteremia and demonstrates that it is a condition with a significant fatality that affects elderly persons with underlying conditions. ß-Lactams represent a rational treatment option.

A population-based study of aerococcal bacteraemia in the MALDI-TOF MS-era.

The purpose of this study was to determine the incidence of aerococcal bacteraemia in the MALDI-TOF MS-era, to describe the clinical presentation and to determine the MIC values of aerococci for ten antibiotics. Aerococci in blood cultures were identified through searches in the laboratory database for the years 2012-2014. MALDI-TOF MS, sequencing of the 16S rRNA gene and a PYR test were used for species identification. Patients' medical charts were systematically reviewed. Etests were used to determine MIC values. Seventy-seven patients were identified (Aerococcus urinae n = 49, Aerococcus viridans n = 14, Aerococcus sanguinicola n = 13 and Aerococcus christensenii n = 1) corresponding to incidences of 14 cases per 1,000,000 inhabitants per year (A. urinae) and 3.5 cases per 1,000,000 inhabitants per year (A. sanguinicola and A.viridans). A. urinae was in pure culture in 61 %, A. sanguinicola in 46 % and A. viridans in 36 % of the cases. The A. urinae and A. sanguinicola patients were old and many had urinary tract disorders, and a majority had a suspected urinary tract focus of the bacteraemia. Eighty percent of the A. urinae patients were men. Five A. urinae patients were diagnosed with infective endocarditis. Six patients died within 30 days. Most isolates had low MICs to penicillins and carbapenems. MALDI-TOF MS has led to an increased identification of aerococcal bacteremia. A. urinae remains the most common Aerococcus in blood cultures and in aerococcal IE.

Clinical and microbiological features of bacteraemia with Aerococcus urinae.

Aerococcus urinae is a Gram-positive bacterium that can cause invasive infection, including infectious endocarditis (IE), mainly in older men. A. urinae is often misclassified in routine diagnostic laboratories. Through searches in the laboratory databases we identify 16 isolates of A. urinae causing bacteraemia during a 6-year period in southern Sweden, indicating that bacteraemia with A. urinae occurs in at least three cases per million inhabitants per year. The identity of isolates was confirmed by sequencing of the 16S rRNA genes and antibiotic susceptibility testing identified two ciprofloxacin-resistant isolates. A. urinae was the only significant pathogen isolated in all cases. Fifteen of the 16 patients were male, 15/16 were more than 70 years old, and 12/16 had underlying urological conditions. Though a urinary tract focus was suspected in the majority of cases, the bacterium was rarely found in urinary samples. Nine patients fulfilled the criteria for severe sepsis and an additional four fulfilled the criteria for sepsis. Only one fatality was recorded. Patients were treated mainly with beta-lactam antibiotics but fluoroquinolones and clindamycin were also used. Three cases of IE were diagnosed and these were complicated by spondylodiscitis in one case and by septic embolization to the brain in one case. An increased awareness of A. urinae is crucial to establishing its role as an important pathogen in older men with urinary tract disease.