Staphylococcus capitis Case Reports Since 1983: A 40-Year Review of the Literature

Giormezis N

Published on: 2023-12-31

Abstract

Staphylococcus capitis was first identified in 1975 and, as a member of the coagulase-negative staphylococci (CNS) group, can be part of the normal human flora. However, infections from this gram-positive bacterium have been reported in the literature. This opportunistic pathogen has the ability to induce a variety of infections, including endocarditis (of prosthetic and native valves), osteomyelitis, and various other infections in adults and children. In this review, all case reports implicating this pathogen since 1983 have been summarized. Despite being a rare pathogen, S. capitis should not be disregarded as a contaminant without further investigation.

Keywords

Staphylococcus capitis; Infections; Case reports; Mini review; Endocarditis; Children

Introduction

Staphylococcus capitis is a member of the coagulase-negative staphylococci (CNS) group. As such, it can be part of the normal human flora. This bacterium was first identified in 1975 and comprises approximately 5% of all coagulase-negative staphylococci isolated in the microbiology laboratory [1]. Like other staphylococci, it has the ability to form biofilms that are resistant to antimicrobials. However, S. capitis displays especially poor adhesion to native tissue or foreign materials compared to S. epidermidis and S. aureus, contributing to the relative lack of virulence [2]. However, infections from this opportunistic pathogen have been reported in the literature. S. capitis has been associated with a variety of infections, including endocarditis, arthritis, pneumonia, cellulitis, catheter-related infections and meningitis.

In this review, all case reports involving this rare pathogen since 1983 have been summarized. A search in Pubmed was performed using the terms Staphylococcus and capitis. The filter for case reports was applied and studies concerning other pathogens or of environmental or veterinary nature were excluded, resulting in 45 articles from 1983 to 2023.

Endocarditis

Endocarditis is the most common infection associated with S. capitis [3]. Most cases include infection of the native heart valves [4-11]. Prosthetic valve endocarditis has also been reported [12-15]. Pacemaker implantation has also been linked to S. capitis infection [16-18].

The first two reports of infective endocarditis due to S. capitis were published in 1992. One of them involved a 53-year-old man with a known mitral valve prolapse and a two-month history of persistent fever, headache, and weight loss. Seven blood cultures were positive for S. capitis. The portal of entry was presumably a large zone of skin irritation on the scalp. After treatment with amoxicillin, netilmicin, and ceftriaxone, the patient recovered [19]. In the same year, Bandres et al. described the case of a 72-year-old man with known severe peripheral vascular disease and a right cerebrovascular infarction who was hospitalized with a 4-day history of fatigue, fever, and mild shortness of breath. A transesophageal echocardiogram showed vegetation on the posterior leaflet of the mitral valve, two blood cultures, and a leg wound culture positive for S. capitis. The patient recovered after treatment with vancomycin and gentamicin [20]. Another case of endocarditis caused by S. capitis subspecies ureolvticus was published in 1993 [21]. An unusual case of acute endocarditis of the patch in a patient treated for tetralogy of Fallot was published by Demarie et al. [22]. One of the earliest cases published in 1998 involved a 73-year-old man with native valve infective endocarditis, most probably secondary to recurrent instrumentation of the oesophagus performed without prophylactic antibiotics [23].

In most cases, S. capitis is susceptible to the latest antimicrobials; however, that is not always the case; in 2018, Hagiya et al. described two cases of cardiovascular device infections associated with daptomycin-non-susceptible CNS. The first involved a 60-year-old woman with a pump pocket infection in a left ventricular assist device, whose blood culture was positive for S. capitis subsp. ureolyticus. The second case involved a 71-year-old man with an aortic graft infection. In this case, non-susceptible S. capitis subsp. ureolyticus was isolated from pus. Both patients finally recovered after treatment with other antibiotics [24]. Recently, a fatal case of endocarditis in a patient with transcatheter aortic valve replacement was published. The patient was not considered a surgical candidate due to a highly calcified aorta and early dementia; therefore, he was treated with cefazolin, gentamicin, and rifampicin but died of cardiac arrest [25].

Orthopedic infections

The first case report of an orthopedic infection caused by S. capitis in adults was published in 2014 and described the occurrence of spondylodiscitis and bloodstream infection due to a vancomycin heteroresistant isolate in a 66-year-old man [26]. Other reports include chronic non-destructive septic arthritis of the knee [27], hip [28] and a 75-year-old woman who underwent two-stage revision surgery of the left hip prosthesis secondary to a S. capitis infection, whose spacer was found to be infected by Candida albicans at a later time [29].

Other adult infections

Capitis is a rare cause of adult meningitis. In 2011, a case of a 65-year-old patient with community-acquired meningitis due to S. capitis, in the absence of traditional risk factors, was published. Despite being treated with vancomycin and meropenem, the patient died after 10 days of hospitalization [30]. Three cases of peritonitis with a good outcome have also been reported [31,32]. S. capitis has also been the cause of two cases of eye infections [33,34]. Other rare infections include pneumonia [35] (including one case from a linezolid-resistant strain [36]), pyomyositis [37], an unusual case of multiple liver abscesses in a 50-year-old woman associated with ventriculoperitoneal shunt infection [38], an infection of cerebro-spinal fluid shunt [39] and a serious case of bacterial granuloma after trauma in a 45-year-old male farmer [40].

Pediatric infections

The search produced only seven case reports involving children over the last forty years, three of which involved neonatal infections. The first one described the nosocomial spread in a neonatal intensive care unit. The authors tested 217 CNS from blood cultures of neonates between 1997 and 2000 for resistance to vancomycin. Forty-eight isolates, identified as S. capitis (including one strain that caused ongoing sepsis), proved heteroresistant to vancomycin [41]. The potential clinical impact of vancomycin heteroresistance was also demonstrated in a report from 2019, where a preterm neonate developed sepsis due to a multi-resistant S. capitis isolate. Bacteremia persisted despite vancomycin treatment and catheter removal, and the patient recovered only after the replacement of vancomycin with linezolid [42]. Another preterm infant had persistent S. capitis septicemia with 11 consecutive positive blood cultures over a period of 33 days and was treated successfully with rifampicin and linezolid [43].

An unusual case of an 11-year-old soccer athlete with acute pelvic osteomyelitis caused by S. capitis was reported in 2010; the disease was associated with repetitive skin injuries of the knee and potential osseous microtrauma. The combination of occult bacteremia resulting from the skin injuries and the pre-existing osseous microtrauma of the acetabulum caused by physical force during rigorous exercise was thought to allow the opportunistic pathogen to colonize the acetabulum [44]. Another case of osteomyelitis of the proximal tibia in a 10-year-old boy with a history of repaired congenital heart disease was published in 2019. Based on the extensive cardiac history and persistent S. capitis bacteremia, the patient was diagnosed with bacterial endocarditis with resultant osteomyelitis from hematogenous bacterial spread [45]. In 2022, an 11-year-old girl presented with a three-day history of fever associated with a frontal headache. An infratentorial subdural empyema as a complication of a parapharyngeal abscess was finally diagnosed, and pus cultures were positive for S. capitis and Streptococcus intermedius [46]. The most benign pediatric case was a keratinizing disorder in 5-year-old Japanese girl caused by swimsuit friction [47].

Conclusion

S. capitis, a member of the CNS group, was first identified in 1975 and is a part of the normal flora of the human ears, neck, face, and scalp. This opportunistic pathogen has the ability to induce numerous infections, such as endocarditis (infecting prosthetic and native valves), osteomyelitis, and various other infections in adults and children. Patients with a suppressed immune system or underlying cardiac disease are considered to be highly susceptible to these infections. Premature neonates are also at high risk. Because of that, S. capitis should not be disregarded as a contaminant without further investigation.

Global Journal of Infectious Diseases and Immune Therapies