Erroneous reporting of coagulase-negative Staphylococci as Kocuria spp. by the Vitek 2 system

Clones and Clusters of Antimicrobial-Resistant Klebsiella From Southwestern Nigeria

BACKGROUND

Klebsiella pneumoniae is a World Health Organization high-priority antibiotic-resistant pathogen. However, little is known about Klebsiella lineages circulating in Nigeria.

METHODS

We performed whole-genome sequencing (WGS) of 141 Klebsiella isolated between 2016 and 2018 from clinical specimens at 3 antimicrobial-resistance (AMR) sentinel surveillance tertiary hospitals in southwestern Nigeria. We conducted in silico multilocus sequence typing; AMR gene, virulence gene, plasmid, and K and O loci profiling; as well as phylogenetic analyses, using publicly available tools and Nextflow pipelines.

RESULTS

Phylogenetic analysis revealed that the majority of the 134 K. pneumoniae and 5 K. quasipneumoniae isolates from Nigeria characterized are closely related to globally disseminated multidrug-resistant clones. Of the 39 K. pneumoniae sequence types (STs) identified, the most common were ST307 (15%), ST5241 (12%), ST15 (~9%), and ST25 (~6%). ST5241, 1 of 10 novel STs detected, is a single locus variant of ST636 carrying dfrA14, tetD, qnrS, and oqxAB resistance genes. The extended-spectrum β-lactamase (ESBL) gene blaCTX_M-15 was seen in 72% of K. pneumoniae genomes, while 8% encoded a carbapenemase. No isolate carried a combination of carbapenemase-producing genes. Four likely outbreak clusters from 1 facility, within STs 17, 25, 307, and 5241, were ESBL but not carbapenemase-bearing clones.

CONCLUSIONS

This study uncovered known and novel K. pneumoniae lineages circulating in 3 hospitals in Southwest Nigeria that include multidrug-resistant ESBL producers. Carbapenemase-producing isolates remain uncommon. WGS retrospectively identified outbreak clusters, pointing to the value of genomic approaches in AMR surveillance for improving infection prevention and control in Nigerian hospitals.

Clinical Features and Outcomes of Kocuria Keratitis and Comparison With Coagulase-Negative Staphylococci Keratitis

PURPOSE

To describe the clinical features and outcomes of Kocuria keratitis and to compare the same with those of Coagulase-negative Staphylococcal (CoNS) keratitis.

METHODS

Medical records of cases with microbiologically proven Kocuria keratitis, seen from January 2011 to December 2017 were reviewed. The data related to predisposing factors, clinical characteristics, antibiotic susceptibility, and the treatment and their outcomes were collected. These parameters were also compared with those of consecutive patients with CoNS keratitis.

RESULTS

Medical records of 23 patients (n = 23 eyes) with Kocuria keratitis were reviewed, and after exclusion of 6 mixed infections, 17 cases with only Kocuria infection were analysed. The median visual acuity at presentation was finger counting 0.5 m [LogMAR 2.00 (1.70-2.70)]. The ulcer was characterized by a central infiltrate (88.2%) involving the anterior stroma (58.8%) with an associated hypopyon (29.4%). Kocuria rosea was the most common species (47.8%). Ninety percent of the isolates identified were susceptible to vancomycin and ofloxacin. In 12 cases (70.6%), the ulcer resolved with the use of topical antibiotics alone in 52 (29-79) days, whereas 3 eyes were subjected to therapeutic penetrating keratoplasty. On comparing the 44 cases of CoNS keratitis, the demographics and the visual acuity at presentation were comparable. Both groups had a similar in presentation response with medical therapy (P, 0.48) and those requiring surgical intervention (P, 0.76).

CONCLUSION

Kocuria is a rare but potential cause of keratitis manifesting in the presence of a compromised ocular surface. Similar to CoNS, it has good clinical response with medical management.

Rare case report of infective endocarditis due to Kocuria kristinae in a patient with ventricular septal defect

Background

Infective endocarditis (IE) is an uncommon but life-threatening infection. It is commonly associated with diseased or damaged valves. Patients with congenital heart disease are more prone to getting IE than the general population. The typical organisms that cause IE include Staphylococcus, Coagulase-negative Staphylococcus, Streptococcus viridians and Enterococci. However, the importance of rare micro-organisms like Kocuria kristinae should not be underestimated especially when isolated from multiple blood cultures in patients suspected of IE.

Case presentation

We report a rare case of right-sided infective endocarditis due to K. kristinae in a young non-diabetic, non-addict female of low socioeconomic class who presented with undiagnosed fever for 1 year. She was investigated and treated for fever by several general practitioners without relief. Later on, she was diagnosed by a local cardiologist to have perimembranous ventricular septal defect with a small pulmonary valve vegetation. She was referred to a tertiary care cardiac hospital in Rawalpindi, Pakistan for further management. Transthoracic and transesophageal echocardiography confirmed IE secondary to preexisting congenital heart disease complicated with a small pulmonary vegetation. Her blood cultures yielded growth of K. kristanae, a rare micro-organism to cause IE. The patient responded to the antibiotic therapy.

Conclusion

Clinicians should have a high index of suspicion for K. kristanae IE as a possible cause of a prolonged fever especially in the presence of congenital heart disease. Antibiotic susceptibility is required for adequate therapy.

Endocarditis bacteriana por Kocuria kristinae en un paciente inmunocompetente. Reporte de caso

Los miembros del género Kocuria corresponden a cocos Gram positivos ubicuos, generalmente inocuos y que hacen parte de la flora saprófita de un porcentaje importante de la población; ocasionalmente han sido descritos como los agentes responsables de patologías infecciosas, principalmente dentro del contexto de pacientes que concomitantemente cursan con enfermedades crónicas y estados de inmunosupresión. Son escasos los casos reportados como causa de endocarditis en pacientes inmunocompetentes a nivel global por especies de este género. Se expone el caso de una mujer inmunocompetente de 44 años, sin antecedentesde importancia, en quien solo el diagnóstico microbiológico permitió confirmar la presencia de Kocuria kristinae como agente causal de su endocarditis infecciosa; la literatura señala la dificultad existente al momento de diferenciar la endocarditis producida por Staphylococcus spp. versus Kocuria kristinae por su evolución clínica similar, indicando la importancia de la microbiología al momento de identificar y diagnosticar apropiadamente.

Clinical presentations, management outcomes, and diagnostic dilemma in Kocuria endophthalmitis

AIM

To describe the clinical presentations and management outcomes of Kocuria endophthalmitis and discuss diagnostic dilemmas DESIGN: Retrospective interventional comparative case series INTERVENTION: Eight unilateral cases with culture-proven Kocuria endophthalmitis from January 2013 to December 2017 underwent vitrectomy/vitreous biopsy and intravitreal antibiotic with or without additional procedures. The undiluted vitreous was subjected to microbiologic evaluation.

MAIN OUTCOME MEASURES

The mean age at presentation, etiology, number of interventions, interval between inciting event and presentation, type of intravitreal antibiotic used, and anatomic and functional outcomes were reported. A favorable anatomic outcome was defined as preservation of the globe, absence of hypotony, attached retina, and absence of active inflammation at the last visit.

RESULTS

In the current series, there were five males and three females. The mean age at presentation was 31 ± 17.44 years (median 30 years). The inciting event was open globe injury in five cases and one case each following cataract surgery, microbial keratitis, and endogenous cause. Visual acuity was ≥ 20/400 in one case at presentation and ≥ 20/400 in three cases at the last visit. The species identified by Vitek 2, included Kocuria kristinae in three, K. rosea in four and K. varians in one. Follow-up period was 8.25 ± 8.24 months (median 6.5). Six cases (75%) had complete resolution of infection and inflammation at the last visit. Anatomic success was achieved in 75%.

CONCLUSIONS

Kocuria is a relatively rare cause of endophthalmitis often misdiagnosed as Staphylococcal endophthalmitis. Clinical presentation can be variable but favorable antibiotic susceptibility and appropriate timely management can result in acceptable visual and anatomic outcomes.

A Case of Community-acquired Bacteremic Empyema Caused by Kocuria kristinae

Kocuria kristinae, part of the normal flora of the skin and oral mucosa, is seldom reported as a human pathogen; infection is mostly associated with immunocompromised patients in healthcare facilities. Here, we describe the first case of bacteremic empyema caused by K. kristinae acquired from the community. K. kristinae was isolated from pleural effusion and two sets of peripheral blood samples drawn from two different sites. The empyema resolved after the insertion of a chest tube and intravenous administration of piperacillin-tazobactam and levofloxacin.

Epidemiology and Outcomes of Kocuria Keratitis

OBJECTIVE

To determine the characteristics of infectious keratitis caused by Kocuria spp.

METHODS

Retrospective case series. Information included demographic data, medical history, risk factors associated with infectious keratitis, clinical characteristics, microbiological results and drug sensitivity, clinical course, management, and visual outcomes.

RESULTS

Eight patients were included (7 females and 1 male; mean age, 66.2 years; age range, 42-84 years). All patients presented risk factors for infectious complications, such as filamentous keratitis, dry eye, blepharitis, and persistent corneal edema. In all cases, ulcers were classified as severe. The infection resolved with medical treatment in one eye only. One case was treated with amniotic membrane graft. Two patients required keratoplasty (lamellar and penetrating), and one case needed sclerokeratoplasty. In three cases, the keratitis was severe enough to require evisceration. The final visual acuity ranged from 20/25 to no light perception.

CONCLUSIONS

Bacterial keratitis by Kocuria spp. is a rare infection that may have an unexpected clinical course and possible serious outcomes. This pathogen should be considered in patients with unusual clinical course. Local or systemic immune compromise in the genesis of the disease must also be taken into account, and ophthalmologists should be more suspicious in this vulnerable group of patients.

Bacteremia Caused by Kocuria kristinae from Egypt: Are There More? A Case Report and Review of the Literature

Kocuria kristinae is opportunistic Gram-positive cocci from the family Micrococcaceae. It is usually considered part of the normal flora that rarely is isolated from clinical specimens. Here, we report a case of Kocuria kristinae bacteremia; to the best of our knowledge, this is the first report from Egypt.

Umbilical Sepsis Caused by Multidrug Resistant Strain of Kocuria kristinae in a New Born: A Case Report

Kocuria species were placed previously under the genus Micrococcus, are skin and oropharynx commensals in mammals, including man. A rare bacteria, Kocuria kristinae isolated from a new born with umbilical sepsis. Identification and antibiotic susceptibility was done by Vitek 2 compact system (Biomerieux). The isolate was sensitive to higher antibiotics like vancomycin, teicoplanin and linezolid. As this new pathogen resembles coagulase negative staphylococcus, it should not be misidentified.

Endocarditis by Kocuria rosea in an immunocompetent child

Kocuria rosea belongs to genus Kocuria (Micrococcaceae family, suborder Micrococcineae, order Actinomycetales) that includes about 11 species of bacteria. Usually, Kocuria sp are commensal organisms that colonize oropharynx, skin and mucous membrane; Kocuria sp infections have been described in the last decade commonly affecting immunocompromised patients, using intravenous catheter or peritoneal dialysis. These patients had mainly bacteremia/recurrent sepsis. We hereby describe the case of a 10-year-old girl, immunocompetent, who had endocarditis/sepsis by K. rosea which was identified in five different blood cultures by Vitek 2 ID-GPC card (BioMérieux, France). Negative HIV serology, blood count within normal range of leukocytes/neutrophils and lymphocytes, normal fractions of the complement, normal level of immunoglobulins for the age; lymphocyte immunophenotyping was also within the expected values. Thymus image was normal at chest MRI. No catheters were required. Identification of K. rosea was essential to this case, allowing the differentiation of coagulase-negative staphylococci and use of an effective antibiotic treatment. Careful laboratory analysis of Gram-positive blood-born infections may reveal more cases of Kocuria sp infections in immunocompetent patients, which may collaborate for a better understanding, prevention and early treatment of these infections in pediatrics.

The expanding spectrum of human infections caused by Kocuria species: a case report and literature review

Although not previously known to cause human infections, Kocuria species have now emerged as human pathogens, mostly in compromised hosts with severe underlying disease. Recently, there has been an increasing incidence of different types of Kocuria infections reported, most likely due to the adoption of better identification methods. Here, we report a case of peritonitis caused by Kocuria rosea in a diabetic nephropathy patient who was on continuous ambulatory peritoneal dialysis. Sepsis and peritonitis caused by K. rosea in our case yielded two identical Kocuria isolates from the peritoneal dialysate fluid within a period of three days. The infection was subsequently resolved by antibiotic treatment and catheter removal. In addition to reporting this case, we herein review the literature concerning the emergence of Kocuria as a significant human pathogen. The majority of cases were device-related, acquired in the hospital or endogenous, and different Kocuria species appear to share a common etiology of peritonitis. The overall disease burden associated with Kocuria appears to be high, and the treatment guidelines for diseases associated with Kocuria have not yet been clearly defined.

Descending necrotizing Mediastinitis caused by Kocuria rosea: a case report

BACKGROUND

Kocuria species are gram-positive, non-pathogenic commensals. However, in immunocompromised patients such as transplant recipients, cancer patients, or patients with chronic medical conditions, they can cause opportunistic infections.

CASE PRESENTATION

We report the first case of descending necrotizing mediastinitis in a 58-year-old, relatively healthy woman caused by Kocuria rosea.

CONCLUSION

Descending necrotizing mediastinitis due to Kocuria rosea can be successfully treated with prompt surgical drainage combined with antimicrobial therapy.

Kocuria kristinae endocarditis related to diabetic foot infection

We report an unusual case of endocarditis occurring in a 74-year-old man with a history of systemic hypertension, diabetes mellitus and minor amputation for left forefoot ulcer. The patient was hospitalized for vacuum-assisted closure therapy to aid in wound healing. After the first treatment session, the patient reported abdominal pain with haematemesis and fever (40 °C). Owing to persistent fever, three blood cultures were performed, all positive for Kocuria kristinae. The identification was based on biochemical tests and automated systems. The speciation of the micro-organism was achieved with MALDI-TOF and then confirmed by 16S rRNA gene sequencing. Transthoracic echocardiographic examination showed the presence of a large vegetation (38×20 mm) on the posterior mitral leaflet and moderate mitral regurgitation. Since there are no current guidelines for the treatment of K. kristinae endocarditis, empiric antibiotic therapy with intravenous sulbactam/ampicillin (1.5 g twice daily) and gentamicin (6 mg kg−1 per day) was started. After 7 days of hospitalization, the patient’s condition suddenly worsened because of the occurrence of haemorrhagic stroke. Despite inotropic support and rifampicin infusion, the haemodynamic status progressively deteriorated. After an initial improvement, he worsened again, becoming stuporous, hypotensive and dyspnoeic. In the following days, the patient developed compartment syndrome resulting in right foot ischaemia. Unfortunately, 25 days after hospitalization, the patient died of multiple organ failure from overwhelming sepsis. To the best of our knowledge, this is the first case of K. kristinae endocarditis on a native valve that is not related to a central venous catheter but associated with diabetic foot infection.

Persistent bloodstream infection with Kocuria rhizophila related to a damaged central catheter

A case of persistent bloodstream infection with Kocuria rhizophila related to a damaged central venous catheter in a 3-year-old girl with Hirschsprung's disease is reported. The strain was identified as K. rhizophila by 16S rRNA gene sequencing and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Arbitrarily primed PCR analysis showed a clonal strain. The repeated septic episodes were resolved with the catheter repair.

Central venous catheter-related bacteremia caused by Kocuria kristinae: case report and review of the literature

Kocuria species are unusual human pathogens isolated most commonly from immunocompromised hosts, such as transplant recipients and cancer patients undergoing chemotherapy, or from patients with chronic medical conditions. A case of catheter-related bacteremia with pulmonary septic emboli in a pregnant adult female without chronic medical conditions is described. A review of other reported Kocuria infections is provided.

Brief Tale of a Bacteraemia by Rhodococcus equi, With Concomitant Lung Mass: What Came First, the Chicken or The Egg?

Rhodococcus equi is an uncommon Gram positive, variably acid-fast pathogen, that appears as hard to treat mostly owing to the establishment of intracellular niches. Lack of interpretive criteria for susceptibility testing may lead to under-reporting or overestimation of resistances, whereas knowledge about this pathogen’s clinical impact may be affected by erroneous phenotype-based characterization at a genus and species level.

We present the case of a bacteraemia with a concomitant lung mass in a lymphoma patient, that further highlights the emergence of rhodococcal diseases as a matter for concern in the fields of infectious diseases and haematology.

Drug sensitivity and clinical impact of members of the genus Kocuria

Organisms in the genus Kocuria are Gram-positive, coagulase-negative, coccoid actinobacteria belonging to the family Micrococcaceae, suborder Micrococcineae, order Actinomycetales. Sporadic reports in the literature have dealt with infections by Kocuria species, mostly in compromised hosts with serious underlying conditions. Nonetheless, the number of infectious processes caused by such bacteria may be higher than currently believed, given that misidentification by phenotypic assays has presumably affected estimates of the prevalence over the years. As a further cause for concern, guidelines for therapy of illnesses involving Kocuria species are lacking, mostly due to the absence of established criteria for evaluating Kocuria replication or growth inhibition in the presence of antibiotics. Therefore, breakpoints for staphylococci have been widely used throughout the literature to try to understand this pathogen's behaviour under drug exposure; unfortunately, this has sometimes created confusion, thus higlighting the urgent need for specific interpretive criteria, along with a deeper investigation into the resistance determinants within this genus. We therefore review the published data on cultural, genotypic and clinical aspects of the genus Kocuria, aiming to shed some light on these emerging nosocomial pathogens.

Kocuria varians infection associated with brain abscess: a case report

Background

Kocuria, established by Stackebrandt et al., previously was classified into Micrococcus. Only two species, K. rosea and K. kristinae are reported to be associated as pathogenic and found with catheter-related bacteremia and acute cholecystitis.

Case presentation

We herein report the first case of brain abscess caused by Kocuria varians, a gram-positive microorganism, in a 52-year-old man. Hematogenous spread is the probable pathogenesis.

Conclusions

This report presents a case of Kocuria varians brain abscess successfully treated with surgical excision combined with antimicrobial therapy. In addition, Vitek 2 system has been used to identify and differentiate between coagulase-negative staphylococcus.

Comparison of the MicroScan, VITEK 2, and Crystal GP with 16S rRNA sequencing and MicroSeq 500 v2.0 analysis for coagulase-negative Staphylococci

Background

Three phenotypic identification systems (MicroScan, VITEK 2, and Crystal GP) were evaluated for their accuracy to identify coagulase-negative staphylococci (CNS). A total of 120 clinical isolates confirmed to be CNS via 16S rRNA sequencing and analysis with the MicroSeq 500 v2.0 database were assessed.

Results

The MicroScan, VITEK 2, and Crystal GP systems correctly identified 82.5%, 87.5%, and 67.5% of the isolates, respectively. Misidentification was the main problem in MicroScan (10.8%) and Crystal GP (23.3%) systems, whereas the main problem of VITEK 2 was low-level discrimination (7.5%).

Conclusion

None of the 3 phenotypic systems tested could accurately and reliably identify CNS at the species level. Further verifications such as biochemical testing or 16S rRNA sequencing together with analysis using a comparable database might be helpful in this regard.

Kocuria rhizophila adds to the emerging spectrum of micrococcal species involved in human infections

We describe the first case of a Kocuria rhizophila infection in a boy with methylmalonic aciduria. A single clone was isolated from blood samples drawn through a port system and from peripheral veins during septic episodes within a 2-year period. K. rhizophila expands the emerging number of "micrococci" considered to be etiologically relevant.

Candida albicans masquerading as gram-negative bacilli in the clinical laboratory

We report misidentification of Candida albicans as Gram-negative bacilli owing to colony morphology on MacConkey agar and subsequent inoculation into GN-ID/VITEK-2. ATCC and clinical Candida strains (n = 24) masqueraded as various bacterial species when experimentally inoculated into GN-ID cards. This phenomenon should be considered when peculiar taxa or susceptibility are encountered.

History and evolution of antibiotic resistance in coagulase-negative staphylococci: Susceptibility profiles of new anti-staphylococcal agents

Coagulase-negative staphylococci (CNS) are a heterogenous group of Gram-positive cocci that are widespread commensals among mammalia. Unlike their coagulase-positive counterpart, Staphylococcus aureus, CNS produce few virulence patterns and normally refrain from invading tissue. Yet, not only can CNS cause infections in normal host tissue, but modern medicine has also seen their rise as opportunists that display adherence to medical device materials to produce a protective biofilm. CNS have historically been more resistant to antimicrobials, including the beta-lactam antibiotics, than S. aureus and some hospitals reveal rates of oxacillin resistance in CNS approaching 90%. Cross resistance to non-beta-lactam agents has been a recurrent theme over the past 40 years in the CNS. Thus, there has been a pressing need for newer antimicrobial agents with good antistaphylococcal activity. Those new agents tend to have excellent antistaphylococcal activity include daptomycin, linezolid, oritavancin, telavancin, tigecycline, dalbavancin, new quinolones, and ceftibiprole, several of which have unique mechanisms of action. The MIC₉₀ for these new compounds typically ranges from 0.5-4 mug/mL. Staphylococcal biofilm formation is quite common in CNS infections and markedly increases the MIC for most older antimicrobials. Several of the newer agents offer some promise of penetration of biofilm to inhibit or kill adherent staphylococci. CNS will likely remain a major cause of infections in the modern age, evolve further antimicrobial resistance mechanisms, and require development of newer antimicrobials for curative therapy.

First case of osteomyelitis caused by "Staphylococcus pettenkoferi"

"Staphylococcus pettenkoferi" (proposed name) was identified as an unusual agent of osteomyelitis in a diabetic foot infection. The phenotypical tests used failed to give a good identification. Molecular 16S rRNA gene and rpoB sequencing allowed us to correctly identify this new species of coagulase-negative staphylococcus responsible for this chronic infection.

Comparative study using various methods for identification of Staphylococcus species in clinical specimens

Coagulase-negative staphylococci (CNS) play a predominant role in nosocomial infections. Rapid, reliable identification of these organisms is essential for accurate diagnosis and prompt effective treatment of these infections. Quite recently, the VITEK 2 g-positive (gram-positive [GP]) identification card (bioMérieux) has been redesigned for greater accuracy in the identification of gram-positive cocci. We compared the BD Phoenix (Becton Dickinson) and VITEK 2 (bioMérieux) automated microbiology systems, using their respective update version cards, and the API ID32 STAPH test. The glyceraldehyde-3-phosphate dehydrogenase (gap) gene-based T-RFLP (terminal restriction fragment length polymorphism) method was used for verifying the results. In total, 86 clinical isolates of CNS and 27 reference strains were analyzed. The results show that for identification of CNS, the automated identification methods using the newest VITEK 2 and BD Phoenix identification cards are comparable. However, API ID32 STAPH revealed more correct results compared to both automated microbiology systems. Despite the increased performance of the phenotypic automated identification systems compared to the former versions, molecular methods, e.g., the gap-based T-RFLP method, still show superior accuracy in identifying Staphylococcus species other than Staphylococcus aureus.

Identification and molecular characterization of mannitol salt positive, coagulase-negative staphylococci from nasal samples of medical personnel and students

The identification of mannitol salt positive, coagulase-negative staphylococci (CNS) is often disregarded when Staphylococcus aureus is screened in clinical samples using mannitol salt agar. However, the emergence of CNS as important human pathogens has indicated that reliable methods for the identification of clinically significant CNS are of great importance in understanding the epidemiology of infections caused by them. The identification and molecular characterization of mannitol salt positive CNS from nasal samples of medical personnel and students is reported here. A total of 84 mannitol salt positive staphylococcal isolates were obtained from 240 nasal samples, of which 15 were CNS. The API STAPH system classified the CNS isolates into six species, and one-third of the isolates were identified with confidence levels of <80 %. 16S-23S rRNA intergenic spacer length polymorphism analysis (ITS-PCR) identified only two species (Staphylococcus haemolyticus and Staphylococcus saprophyticus). This identification was confirmed by antibiotyping, species-specific PCR and PFGE. The results from this study indicate that ITS-PCR is a potentially useful and reliable tool, enabling hospital laboratories to obtain rapid, full and accurate identification of CNS at the species level.

Identification of biochemically atypical Staphylococcus aureus clinical isolates with three automated identification systems

Between January and April 2002, a total of 271 strains of Staphylococcus aureus were isolated from clinical specimens at Toho University Omori Hospital, Japan, including 201 (74.2 %) which were identified as meticillin-resistant S. aureus (MRSA). However, 34 (12.5 %) were biochemically atypical, because they did not produce acid on mannitol salt agar or did not agglutinate in Staphaurex testing but were categorized as MRSA by PCR analysis and by antibiotic susceptibility. Three automatic identification systems, AutoScan-4 (Dade Behring), BD Phoenix (Becton Dickinson) and Vitek 2 (bioMérieux), were evaluated by testing these atypical S. aureus isolates. The AutoScan-4 and Phoenix systems identified all 34 isolates as S. aureus. Without additional tests such as Staphaurex, observation of colony pigment and haemolysins on sheep blood agar, Vitek 2 identified only 16 isolates (47.1 %) as S. aureus with good or better confidence levels and misidentified one of the remaining isolates as Staphylococcus chromogenes. This study shows that it is possible to identify these physiologically atypical S. aureus isolates correctly by using the Phoenix and AutoScan-4 fully automatic identification systems.

Kocuria kristinae infection associated with acute cholecystitis

BACKGROUND

Kocuria, previously classified into the genus of Micrococcus, is commonly found on human skin. Two species, K. rosea and K. kristinae, are etiologically associated with catheter-related bacteremia.

CASE PRESENTATION

We describe the first case of K. kristinae infection associated with acute cholecystitis. The microorganism was isolated from the bile of a 56-year old Chinese man who underwent laparoscopic cholecystectomy. He developed post-operative fever that resolved readily after levofloxacin treatment.

CONCLUSION

Our report of K. kristinae infection associated with acute cholecystitis expands the clinical spectrum of infections caused by this group of bacteria. With increasing number of recent reports describing the association between Kocuria spp. and infectious diseases, the significance of their isolation from clinical specimens cannot be underestimated. A complete picture of infections related to Kocuria spp. will have to await the documentation of more clinical cases.