Streptococcus milleri head and neck abscesses: a case series.
Streptococcus milleri infections and abscesses in the head and neck region have been previously reported, but there is still a dearth of clinical literature on this topic. To add to the available reports and to promote a better understanding and awareness of this clinically important entity, we present this retrospective review of 7 cases of head and neck abscess caused by S milleri infection. We have placed particular emphasis on antibiotic sensitivity patterns. These patients--6 men and 1 woman, aged 28 to 73 years (mean: 42.7)--had been seen at a district general hospital in Gosford, Australia, over a 6-month period. All patients had undergone surgical intervention and had been treated with intravenous antibiotics. All the S milleri cultures were sensitive topenicillin G, cephalexin, and erythromycin. Six of these patients experienced a resolution of their abscess, while 1 patient died from overwhelming sepsis. We believe that the initiation of penicillin G, cephalexin, or erythromycin is a good starting point for empiric therapy. S milleri should be considered as a causative organism in a patient who presents with a head and neck abscess, especially in the presence of a dental infection. Such a patient should be monitored closely for airway obstruction and distal infective sequelae. Also in this article, we compare our findings with those reported in two other published series.
Streptococcus milleri comprises a group of three distinct gram-positive species: Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus. The
identification and classification of this group of bacteria have been historically complicated, and hence recognition of S milleri infections may be under-reported. (1)
Guthof coined the term Streptococcus milleri in 1956 to describe nonhemolytic streptococci that were isolated from oral infections; his intention was to honor oral microbiologist W.D. Miller (1853-1907). (2) S milleri is a common commensal organism found in the oral cavity, gingival crevices, dental plaque, dental root canals, throat, oropharynx, gastrointestinal tract, appendix, stool, and the vaginal canal. (3)
S milleri is well known for its ability to cause purulent infections and abscesses at various sites in the body. Infections caused by this organism usually occur in the abdominal/hepatobiliary system and in the thoracic cavity, while abscesses usually occur in the liver, abdomen, pelvis, lung, and brain. (4)
A number of cases of S milleri infections and abscesses of the head and neck region have been previously reported, but there is still a dearth of clinical literature about these pathologies. Han and Kerschner (5) in Milwaukee published a series of 26 cases in 2001, and Hirai et al (6) in Hiroshima reviewed 17 cases in 2005. We describe a small series of patients with an abscess of the head and neck caused by S milleri infection, and we pay particular attention to antibiotic sensitivities in comparison with the two previous case series. It is our wish to add to the available literature and to promote a better understanding and awareness of this clinically important entity.
Patients and methods
We retrospectively reviewed 7 cases of head and neck abscess secondary to S milleri infection that had been treated over a 6-month period in the Department of Otolaryngology at Gosford Hospital in New South Wales, Australia. The 7 patients included 6 men and 1 woman, aged 28 to 73 years (mean: 42.7).
In addition to demographic data, we compiled information on the site of the abscess, comorbidities, the clinical presentation and treatment, outcomes, and inpatient and discharge antibiotic regimens. We also paid particular attention to culture sensitivity patterns. Pus cultured from each of the 7 patients had grown S milleri. Identification of the causative pathogen had been made by the hospital's microbiology service. (At Gosford Hospital microbiologic cultures are reported only as S milleri; they are not further subclassified as either S intermedius, S constellatus, or S anginosus.)
Once our data were complied, we compared our findings with those of Han and Kerschne (5) (the Milwaukee group) and Hirai et al (6) (the Hiroshima group), keeping in mind that our study included only abscesses, while the other two studies included both S milleri infections and abscesses.
Our findings are summarized in table 1, and a comparison of our findings with those of the Milwaukee group and the Hiroshima group is shown in table 2.
Sex and age. The male preponderance in our population (86%) was similar to the proportions of both the Milwaukee group and the Hiroshima group--81 and 71%, respectively. Incidentally, in a review of 28 cases of S milleri infection throughout the body, Shlaes et al also found a striking predisposition for males (6:1). (7)
With respect to age, our group was obviously older than the pediatric cohort in the Milwaukee group, and it was generally similar to the Hiroshima group.
Site of abscess. The most common site of abscess in our series was the submandibular space, wherein 5 of 7 cases (71%) were located. This is in contrast to both the Milwaukee and Hiroshima groups, where sinus involvement was most common (the paranasal and maxillary sinuses, respectively.) On the other hand, our finding is compatible with that of an Italian review of 24 deep neck space infections, which found that 67% of the abscesses studied occurred in the submandibular space. (8) It is interesting that in the Italian study, the most common organism isolated from those abscesses was S milleri, which accounted for half of the total.
Comorbidities. Three of the 7 patients in our study (43%) had at least one major comorbidity, the most common being diabetes mellitus. In the Milwaukee group, only 1 of the 26 patients (4%) had a major comorbidity (cystic fibrosis), but this is not surprising considering that this group represented a purely pediatric population. In the Hiroshima group, a major comorbidity was documented in 3 of the 17 patients (18%); there was 1 case each of diabetes mellitus, human immunodeficiency virus infection, and heart failure.
Treatment. All of our patients required surgical intervention and treatment with at least one intravenous antibiotic. Overall, our patients were treated successfully and relatively easily, even though nearly all of them exhibited signs of systemic sepsis on presentation. The exception was patient 5, who died as a direct result of overwhelming S milleri sepsis from his head and neck abscess. A similar death from sepsis in a patient with S milleri head and neck infection was reported in Wales by Flanagan and Mills in 1994. (9) In their case, the deceased patient was a previously healthy adult, whereas our patient had coexisting diabetes mellitus. Jacobs et al reported a series of predominately intra-abdominal S milleri infections in which the mortality rate reached 22%. (10)
Outcomes. Only 1 of the 6 survivors (patient 7) had a difficult course once treatment was initiated. The others were hospitalized for less than 1 week.
Length of stay. The mean length of hospital stay in our series was 8 days. This excluded 1 case in which the patient self-discharged against medical advice on day 3, and the 1 death, which occurred on day 22.
Sensitivity patterns. The S milleri cultured from our patients exhibited universally identical sensitivity patterns, as all the isolates were sensitive to penicillin G, cephalexin, and erythromycin. By contrast, the Milwaukee study found a slight decline in the sensitivity of S milleri to penicillin over the 3-year period from 1996 to 1999, and a much greater decline in sensitivity to erythromycin (from 97 to 84%) over the same 3 years. In the Hiroshima group, only 71% of cases were sensitive to ampicillin, but 100% were sensitive to second-, third-, and fourth-generation cephalosporins. These differences illustrate the regional variations in antibiotic sensitivities in S milleri. In our series, cultures of 4 of the 7 patients (57%) grew organisms other than S milleri; corresponding figures in the Milwaukee and Hiroshima groups were 31 and 53%. In the pediatric (Milwaukee) group, these concomitantly cultured organisms included Aspergillus fumigatus, Eikenella corrodens, Haemophilus influenzae, Peptostreptococcus spp, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae. In the adult (Hiroshima) group, they included anaerobes, Fusobacterium spp, Haemophilus spp, methicillin-susceptible S aureus, Peptostreptococcus spp, and Prevotella spp. Our series shows a similar incidence of concomitantly cultured organisms in an adult population.
In many ways, our findings were similar to those of the Milwaukee (5) and Hiroshima studies. (6) A notable exception was the difference in antibiotic sensitivity patterns, which are presumably influenced by local antibiotic prescribing practices and environmental factors.
S milleri has several properties that make it so pathogenic. It appears to induce less chemotaxis of polymorphonuclear leukocytes than does S aureus, a common abscess-forming pathogen, (11) and this allows S milleri more time to proliferate prior to phagocytosis. It also appears that it takes leukocytes more time to kill S milleri once they have been phagocytosed, the rate of killing by leukocytes being substantially slower than the rate of killing of S aureus. (11)
S milleri possesses several other cell-surface characteristics that may promote the formation of abscesses, including the production of hyaluronidase. Hyaluronic acid is a major component of the interstitial barrier, and its hydrolysis by hyaluronidase increases the permeability of tissues. (12)
One of the three S milleri subtypes, S intermedius, has been shown to produce a human-specific cytolysin called intermedilysin. Intermedilysin is known to lyse cells of the human immune system, including neutrophils. The presence ors intermedius in sites of deep infection correlates with an increase in the production of this cytolysin. Moreover, S intermedius cultured from dental plaque has also exhibited this increased production. (13)
In vitro studies of S milleri have found a gliding type of motility across surfaces with the production of an extracellular material. This is thought to aid movement in the apparent absence of traditional organs of motility such as flagella. (14) It has been proposed that this may aid in the spread of infective organisms in vivo.
The pathogenicity of S milleri is enhanced by its ability to spread hematogenously. (15) In our series, patient 5 developed infective endocarditis several days after his admission. The ability of S milleri to spread hematogenously, to bind fibronectin, and to cause aggregation of platelets and then be incorporated into clots has been widely implicated in the development of endocarditis. In some studies, 9 to 15% of cases of community-acquired endocarditis have been reported to be caused by S milleri. (16)
In view of the potential for hematogenous spread of S milleri in the head and neck region, prompt and definitive treatment is vital in order to prevent intracranial sepsis. S milleri is the most common organism isolated from sinus-disease-related intracranial sepsis. (12) Another reason for prompt treatment is the space-occupying nature of some head and neck abscesses, which can rapidly lead to airway compromise, as occurred in patient 5 and patient 7 (figure) in our series.
In conclusion, S milleri should be considered as a causative organism in a patient who presents with a head/neck abscess, especially in the presence of poor dental hygiene. The possibility of rapid deterioration, airway compromise, and involvement of anatomically distant organs must be kept in mind. Individual antibiotic sensitivities should be sought as soon as possible, but empiric antibiotic therapy with penicillin or a cephalosporin appears to be very appropriate, at least in Australia. The presence of a co-organism should also be borne in mind.
We thank Dr. Rosemary Stratford of the Emergency Department at Gosford Hospital and Mr. Julian Savage of the ENT Department at Southmead Hospital in Bristol, U.K.
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(3.) Mirzanejad Y, Stratton CW. Streptococcus anginosus group. In:
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(8.) Jankowska B, Salami A, Cordone G, et al. Deep neck space infections. Int Congr Ser 2003;1240:1497-1500.
(9.) Flanagan PG, Mills RG. Fulminant septicaemia due to Streptococcus milleri infection in a previously healthy adult. Eur J Clin Microbiol Infect Dis 1994;13(3):247-8.
(10.) Jacobs JA, Tjhie JH, Smeets MG, et al. Genotyping by amplified fragment length polymorphism analysis reveals persistence and recurrence of infection with Streptococcus anginosus group organisms.
J Clin Microbiol 2003;41(7):2862-6.
(11.) Wanahita A, Goldsmith EA, Musher DM, et al. Interaction between human polymorphonuclear leukocytes and Streptococcus milleri group bacteria. J Infect Dis 2002; 185(1):85-90.
(12.) Willcox MD, Knox KW. Surface-associated properties of Streptococcus milleri group strains and their potential relation to pathogenesis.
J Med Microbiol 1990;31(4):259-70.
(13.) Nagamune H, Whiley RA, Goto T, et al. Distribution of the intermedilysin gene among the anginosus group streptococci and correlation between intermedilysin production and deep-seated infection with Streptococcus intermedius. J Clin Microbiol 2000;38(1):220-6.
(14.) Bergman S, Selig M, Collins MD, et al. "Streptococcus milleri" strains displaying a gliding type of motility. Int J Syst Bacteriol 1995;45(2):235-9.
(15.) Claridge JE III, Attorri S, Musher DM, et al. Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus ("Streptococcus milleri group") are of different clinical importance and are not equally associated with abscess. Clin Infect Dis 2001;32 (10):1511-15.
(16.) Willcox MD. Potential pathogenic properties of members of the "Streptococcus milleri" group in relation to the production of endocarditis and abscesses. J Med Microbiol 1995;43(6):405-10.
Christopher Robert Foxton, MA(Oxon); Smariti Kapila, MBBS; Justin Kong, MBBS; Neil John Thomson, FRACS
From the Department of ENT, Bristol Royal Infirmary, Bristol, U.K. (Dr. Foxton); the Department of ENT, Royal Prince Albert Hospital, Sydney, Australia (Dr. Kapila); the Department of ENT, Sydney Medical School, University of Sydney (Dr. Kong); and the Department of ENT, Gosford Hospital, Gosford, Australia (Dr. Thomson). The work described in this article was performed at Gosford Hospital.
Corresponding author: Dr. Christopher Robert Foxton, 43 St. John's Rd., Clifton, Bristol BS8 2HD, UK. Email: email@example.com
Table 1. Selected characteristics of the 7 patients Patient 1 Patient 2 Age (yr)/sex 39/M 37/M Site of abscess Left submandibular Left maxillary space space Comorbidities Poor dentition Diabetes mellitus Clinical Patient 1 presented Patient 2 presented presentation and febrile and with rigors and treatment tachycardic with bilateral facial fluctuant pain and swelling; submandibular the swelling was swelling; incision most pronounced over and drainage was the left zygomatic performed in the arch; pus was being operating room; in discharged from a addition, a decayed decayed left upper molar with free pus molar, which was from the socket was extracted in the extracted; the operating room cavity was packed with a wick and progressively shortened over 5 days Outcome Discharged home well Discharged home well on day 6 on day 4 Inpatient Penicillin G for 6 Penicillin G and intravenous days metronidazole for 4 antibiotic regimen days Outpatient oral Amoxicillin and Amoxicillin/ antibiotic regimen metronidazole for 14 clavulanate for 14 days days Patient 3 Patient 4 Age (yr)/sex 73/F 28/M Site of abscess Left submandibular Left submandibular space space Comorbidities Ischemic heart Poor dentition disease, peripheral vascular disease, diabetes mellitus Clinical Patient 3 presented Patient 4 presented presentation and afebrile and afebrile, but with treatment systemically well, left dental pain and but with an increasing facial increasing swelling and submandibular under the left angle swelling; the of the mandible; presence of an formal incision and abscess was drainage in the confirmed on CT; operating room was local anesthesia was performed, and a administered, and Penrose drain was the abscess was placed drained; a wick dressing was placed and progressively shortened Outcome Discharged home well Self-discharged on day 4 against advice on day 3 Inpatient Penicillin G, Penicillin G and intravenous metronidazole, and metronidazole for 3 antibiotic regimen flucloxacillin days (floxacillin) for 4 days Outpatient oral Amoxicillin and Amoxicillin/ antibiotic regimen metronidazole for 14 clavulanate for 14 days days Patient 5 Patient 6 Age (yr)/sex 46/M 37/M Site of abscess Bilateral Right submandibular parapharyngeal space spaces Comorbidities Diabetes mellitus, Poor dentition developmental delay, and a ventricular septal defect that closed during childhood Clinical Patient 5 presented Patient 6 presented presentation and with fever, rigors, systemically unwell; treatment and low blood a discharging pressure; increasing abscess was present swelling was present under the angle of in the submandibular the mandible; CT spaces, and confirmed the laryngeal structures presence of a were not easily multiloculated palpable; an awake abscess cavity; 2 fiberoptic decaying mandibular intubation by teeth were removed incision and in the operating drainage was room, and pus was performed in the evacuated from both operating room sockets Outcome Required high-dose Discharged home well inotropes in the on day 5 ICU; developed infective endocarditis followed by bowel ischemia that required resection; died from overwhelming sepsis on day 22 Inpatient Penicillin G and Penicillin G and intravenous metronidazole metronidazole for 5 antibiotic regimen followed by days meropenem; 22 days in all Outpatient oral N/A Amoxicillin/ antibiotic regimen clavulanate for 14 days Patient 7 Age (yr)/sex 39/M Site of abscess Right submandibular space Comorbidities Poor dentition Clinical Patient 7 presented presentation and systemically unwell; treatment an increasing submandibular swelling had arisen following the recent extraction of a 4.8 molar; an awake fiberoptic intubation was performed, followed by incision and drainage in the operating room a total of 3 times over 6 days; the abscess extended to within 1.5 cm of the skull base on the opposite side (figure) Outcome Discharged home well on day 21, following prolonged ICU support Inpatient Cefazolin, Inpatient metronidazole, and Inpatient gentamicin, followed by ceftriaxone; 21 days in all Outpatient oral Amoxicillin/ antibiotic regimen clavulanate for 14 days Table 2. Comparison of reported head and neck S milleri cases Milwaukee Hiroshima Present series groups groups (n = 7) (n = 26) (n = 17) Males, n (%) 6(86) 21 (81) 12(71) Mean age, yr 42.7 10.7" 62 Most common site Submandibular Paranasal Maxillary of abscess space sinuses sinuses Patients with a 3 (43) (most 1 (4) 3(18) major comorbidity, common: n (%) diabetes mellitus) Most common Penicillin G Ampicillin/ Unknown intravenous (IV) sulbactam antibiotic Mean duration of IV 9.3 9.9 Unknown antibiotic use, days Most common oral Amoxicillin/ Amoxicillin/ Unknown antibiotic clavulanate clavulanate Mean duration of 14 12.3 Unknown oral antibiotic use, days * Pediatric cohort.
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|Title Annotation:||ORIGINAL ARTICLE|
|Author:||Foxton, Christopher Robert; Kapila, Smariti; Kong, Justin; Thomson, Neil John|
|Publication:||Ear, Nose and Throat Journal|
|Article Type:||Case study|
|Date:||Jun 1, 2012|
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