Isolation of Arcanobacterium haemolyticum from an infected foot wound

Outbreak of Arcanobacterium haemolyticum in chronic wounds in The Netherlands

INTRODUCTION

Aging and comorbidities such as diabetes and vascular problems contribute to the increasing occurrence of chronic wounds. From the beginning of 2016, a marked increase in Arcanobacterium haemolyticum (ARH) in chronic wound cultures was noted among patients visiting a wound expertise centre in The Netherlands.

AIM

To report the outbreak investigation of ARH cultured from chronic wounds and describe the implemented infection prevention measures.

METHODS

In total, 50 ARH isolates were sent to a reference laboratory for molecular typing. Samples for bacterial culture and ARH polymerase chain reaction were taken from care workers, the environment and items used for wound care. Infection prevention measures were implemented in a bundled approach, involving education, better aseptic wound care conditions and hygienic precautions. Before and after the implementation of infection prevention measures, two screening rounds of ARH testing were performed among all patients receiving home care.

RESULTS

ARH isolates from wound care patients were found to be identical by core genome multi-locus sequence typing. No definite outbreak source could be determined by culture. However, three pairs of forceps, used by two nurses on multiple patients, were found to be ARH positive by polymerase chain reaction. In the two screening rounds before and after the implementation of infection prevention measures, the proportion of ARH-positive patients decreased significantly from 20% (20/99) to 3% (3/104). Subsequently, no new cases occurred.

CONCLUSION

This first ARH outbreak was likely caused by re-using contaminated instruments. Through the implementation of improved infection prevention measures and re-education of all employees involved, the outbreak was controlled. With the current trend of care transition, infection control must be a major concern.

Complete genome sequence of Arcanobacterium haemolyticum type strain (11018)

Arcanobacterium haemolyticum (ex MacLean et al. 1946) Collins et al. 1983 is the type species of the genus Arcanobacterium, which belongs to the family Actinomycetaceae. The strain is of interest because it is an obligate parasite of the pharynx of humans and farm animal; occasionally, it causes pharyngeal or skin lesions. It is a Gram-positive, nonmotile and non-sporulating bacterium. The strain described in this study was isolated from infections amongst American soldiers of certain islands of the North and West Pacific. This is the first completed sequence of a member of the genus Arcanobacterium and the ninth type strain genome from the family Actinomycetaceae. The 1,986,154 bp long genome with its 1,821 protein-coding and 64 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

Isolation, in vitro antimicrobial susceptibility and penicillin tolerance of Arcanobacterium haemolyticum in a Turkish university hospital

Arcanobacterium haemolyticum (Ah) was isolated from 5 (0.3%) out of 1531 throat cultures of patients with presumed pharyngotonsillitis. The age of the patients who had a positive culture for Ah varied between 6 and 22. The isolation rate of beta-haemolytic streptococci (BHS) was 7.4%, 72.6% of which belonged to Group A, followed by groups G, C and B. None of the throat samples yielded simultaneous growth of Ah and BHS. Antimicrobial susceptibility of Ah isolates to phenoxymethylpenicillin, cephalexin, cefotaxime, vancomycin, erythromycin, azithromycin, doxycycline, ciprofloxacin, and trimethoprim-sulfamethoxazole was tested by the agar dilution method. The isolates were found to be susceptible to all antimicrobials tested except trimethoprim-sulfamethoxazole. Penicillin tolerance could be detected in none of the Ah strains, including the reference strain Ah ATCC 9345. We conclude that Ah should be kept in mind as a potential pathogen causing pharyngitis in adolescents and young adults.

Clinical microbiology of coryneform bacteria

Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed.