Oral Microbioi Immutwl 1991: 6: 123-125
Aerobic and anaerobic microbioiogy of periapicai abscess
llzhak Brook, Edith H. Frazier, IVIarlin E. Gher Naval Medical Center, Bethesda, Maryland, USA
orook I, Erazier EH, Gher ME, Aerobic atid anaerobic tnicrobiology of periapical abscess. Oral Micfobiol Ittmmttol 1991: 6: 123-125. Aspirates of pus from periapical abscesses in 39 patients were studied for aerobic and anaerobie bacteria. Bacterial growth was present in 32 specimens, A total of '8 bacterial isolates (55 anaerobic and 23 aerobic and facultative) were recovered, accounting for 2.4 isolates per specimen (1.7 anaerobic and 0,7 aerobic and lacultatives). Anaerobic bacteria only were present in 16 (50%) patients, aerobic and facultatives in 2 (6%), and mixed aerobic and anaerobic flora in 14 (44%). The predominant isolates were Bacteroides spp. (23 isolates, including 13 Bacteroides melatiinogenicus group). Streptococcus spp, (20), anaerobic cocci (18), and fusobacterium spp, (9). Beta-lactatnase-producing organistns were reeovered from / of the 21 (33%) specimens that were tested. This study highlights the polytnicrobial nature and itnportance of anaerobie bacteria in periapical abscess.
fhe flora associated with odontogenic infections is complex and generally reflect the combined infiuenee of the indigenous oral flora and the unique flora of the underlying conditions, Polymicrobtai aerobic-anaerobic flora was isolated also from cases of dentoalveolar abseesses (13). Studies done at the turn of the century of acute and chronic alveolar abscesses described the isolation of predominantly aerobic streptococci; however, fusiform bacilli and Bacteroides spp, were found in some abscesses, sometimes in pure culture. More recent studies report the isolation of a variety of anaerobes in periapical abscesses, including anaerobic cocci, anaerobic gram-negative bacilli, and anaerobic gram-positive bacilli (18), Since many of the anaerobes have been reelassified and renatned according to newer criteria for their identification, a more current evaluation of the incidence of recovery of anaerobie bacteria from this infeetion is desirable. Such a study tnay better show the frequeney of the recovery of anaerobes frotrt periapteal abscesses today and tnay also present the effect of these improvements on the recovery of these organisms.
he opinions and assertions contained herein ''re the private ones of the writer, and are not ° be construed as official or reflecting the J^ews of the Departtnent of Defense, the Navy Department, or the Naval Service at 'arge.
Material and methods
Between June 1975 and June 1985, 39 aspirates of periapical abscesses were processed for aerobic and anaerobic bacteria by the Clinical Microbioiogy Laboratories at the Naval Medical Center in Bethesda, MD, Bacterial growth was present in 32 instances. All the following data pertain only to these 32 patients. The mean patient's age was 43 years (range 8 years to 69 years) and 19 were tnales. Eleven of the patients received antitnicrobial therapy prior to sample collection. A beta-lactam-resistant penicillin (oxaeillin or dicloxacillin) was given to 6 patients, erythromycin to 3 and atnpieillin to 2, Cultures were obtained after cleansitig the oral mueous surface with povidone-iodine, by either direct needle aspiration of purulent contents or during surgical incision and drainage. The material was placed into a syringe that was imtnediately sealed and transported to the laboratory within 30 tnin, or by a swab that was dipped into the pus and introduced into anaerobie transport systetn (Port-A-Cul, BBL Microbiology Systetns, Coekeysville, MD), that was transported to the laboratory within 2h. For anaerobic bacteria, and specimen tnaterial was plated onto prereduced vitamin K,-enriched Brueella blood agar, an anaerobic blood plate containing colistin atid nalidixic aeid, and an enriched thioglycolate broth (contain-
Key words; periapical abscess; Bacteroides spp Itzhak Brook, M, D,, M, Sc, Armed Forces Radiobiology Research Institute, Bethesda, MD 20814-5145, USA Accepted for publication May 21, 1990
ing hemin and vitamin K,) (18), iticubated in GasPak jars (BBL Microbiology Systems), and examined at 48 and 96 h. Plates that showed growth were held utitil the organistns were processed and identified. All cultures that showed no growth were held for at least 7 d. Anaerobes were identified using the Minitek systetn (BBL Microbiology Systetns). In addition to these tests, other carbohydrate tests (Seott Laboratories, Fiskeville, RI) and gas hquid ehromatography (18) were performed as needed to identify the organisms. For aerobic bacteria, sheep blood (5%), chocolate and MacConkey's agar plates were inoculated at 37°C aerobically (MacConkey) and under 5% CO, (blood and chocolate), and examined at 24-48 h. Aerobic bacteria were identified using conventional methods (11). Beta-lactamase activity was determined on isolates reeovered from satnples usitig the chromogenic cephalosporin analog 87/312 methodology (15), Results
Anaerobic bacteria only were recovered in 16 (50%) specimens, aerobic or facultative baeteria only in 2 (6%) and mixed aerobic and anaerobic bacteria were recovered in 14 (44%), A total of 78 bacterial isolates were recovered, accounting for 2.4 isolates per speeitnen (1.7 anaerobes and 0,7 aerobes per specitnen) (Table 1). A total of 55 anaerobic bacteria were
124
Brook
bic isolates the most frequent ones were Streptococcus salivarius, and alpha-heAnaerobic bacteria Aerobic and facultative baeteria molytic streptococci. Staphylococeus aureus I Peptostreptococeus spp, Heimdahl et al. (9) evaluated 48 paStreptococcus milleri 3 Peptostreptococcus anaerobius Streptococcus mitior 1 Peptostreptocoecus micros tients with acute orofacial infections of Streptococcus satiguis 2 Peptostreptococeus prevotti odontogenic origin ineluditig periapical Streptococcus faecaiis 3 Peptostreptococeus intermedius abscess, A total of 174 anaerobic and 22 Alpha-hemolytic streptococcus 11 Propionbacterium acnes aerobic bacterial strains were isolated. Haemophilus parainjluenzae 2 Eubacterium lentum Anaerobic gram-negative rods and esVeillonella parvula pecially E. nucleatum were isolated more Eusobactertum spp, frequently from the patients with severe Eusobacterium nucleatum infections than from the patients with Eusobacteria mortiferum infections judged as mild. Bacieroides spp, Bacteroides fragilis Oguntebi et al. (16) studied 10 periBacteroides ovatus apical abscess in patients free of perioBacteroides meianinogenicus dontal disease. Mixed flora was idenBacteroides asaccharolyticus tified in all instatices. The most common Bacteroides intermedius isolates were F. nucleatum and StreptoBacteroides gingivalis coccus mitis, which were co-isolated in Bacieroides oralis 6 instances. Bacteroides oris-buccae In recent quantitative and qualitative Total 23 Total 55 study of 50 dentoalveolar abseess, Lewis et al, (12) recovered 3.3 isolates per abscess. Twenty (40%) abseesses conrecovered. No difference was noted in might have enabled the reeovery of tained anaerobes only, and 27 (54%) the recovery of organisms and the iso- some of the slow-growing organisms. It abseesses had a mixture of both aerobes lation of beta-lactamase producing bac- is also possible that obtaitiing concomi- and anaerobes. Three fourths of the isoteria between the patients that received tant cultures through a root canal might lates were strict anaerobes; the tnost antimicrobial agents and those that did have itnproved the recovery rate. How- commoti ones were Peptostreptococcus not. The predominant anaerobes recov- ever, such a procedure may be associ- spp., B, oralis and B. melatiinogenicus. ered were Bacteroides spp. (23 isolates), ated with contamination of the speci- The mean concentration of bacteria in anaerobic cocci (18 isolates), and Euso- mens by oral flora, since no mucosal each abscess was lO*''**''^. The mean bacterium spp, (9 isolates). A total of surface culture was taken after disinfec- eoncentration of anaerobic bacteria was 23 aerobic and facultative isolates were tion, the possibihty of contaminating JQ6.2+O,2 ^J^JJ QJ- facultatively anaerobic bacteria 105'±»l recovered. The predominant aerobic the specimens was not excluded. isolates were Streptococcus spp, (20 isoSerious cotnplications from periThe isolation of anaerobie bacteria lates). Only one consistent pattern of alone or mixed with aerobic and faculta- apical infections are relatively rare, concombinations was noted between tive organisms at that site is not surpris- sidering the enortnous numbers of inBacteroides spp, and Peptostreptococcus ing, since anaerobes are the predomi- feeted teeth that occur in the populaspp. (13 instances). nant organisms in the oropharynx, tion. However, in sotne cases, the Single bacterial isolates were recov- where they outnumber aerobes in the infection spreads to tissues in other porered in 3 instances. These included one ratio of 10 to 1 to 1000 to 1 (17), and fions of the oral cavity, causing submanisolate each of Bacteroides intermedius, are important pathogens in other snp- dibular or superficial sublingual abEusobacterium nucleatum, and Pepto- purative infeetion in and around the or- seesses; abscesses may be produced also in the submaxiliary triangle or in the opharynx (2). streptococcus micros, Beta-lactamase production was deThis study supports the reeovery of parapharyngeal or submasseterie spaee. In the maxilla, periapical infection tected in 8 isolates recovered from 7 of polymierobial flora in periapieal abthe 21 (33%) specimens that were seesses reported before (6, 7, 9, 12, 16). may affect only the soft tissues of the tested. These included the 2 members Chow et al. (7) recovered anaerobes in face. It may extend, however, to the of the Bacteroides fragilis group, all 3 all 4 periapical abscesses, in 3 also infratemporal space, including the sinuses, and then to the nervous system, Bacteroides meianinogenicus and one mixed with aerobic bacteria. isolate each of B. intertnedius, BacterIn a study of the bacteriology of peri- where it can cause serious complications oides asaecharolyticus and Staphylococ- apical abscess in 12 children (6), an- such as subdural enipyema, brain abcus aureus. aerobes were isolated in all patients. An- scess, or meningitis (3, 5, 8). aerobes were the only organism isolated The finding of anaerobic bacteria in in two thirds of the patients, and in the periapical abseesses is of importance beDiscussion rest they were mixed with aerobes. Of cause of the association of anaerobes This study illustrates the importance of the 53 anaerobie isolates the predomi- with many serious infections arising anaerobic bacteria in periapical abscess- nant ones were Bacteroides species, B, from dental foci, such as bacteremia, es, where these organisms were isolated meianinogenicus group, Bacteroides ora- endocarditis, sinusitis, menitigitis, subin 94% of the studied patients. It is lis, and Baeteroides ureolyticus, anaer- dural empyetna, brain abscess, and pulpossible that prolonging the incubation obie gram-positive cocci, fusobacteria, monary empyema (8, 10). of specimen to a period longer than 7 d and Actinomyces speeies. Of the 6 aeroOur data demonstrate the presence of Table 1. Bacterial isolates in 32 periapical abscesses
Microbiology of periapical abscesses
beta-lactamase-producing organisms in 33% of the tested abscess specimens. These organistns can survive penicillin therapy and may also protect penicillinsusceptible bacteria from penieillin by releasing the enzyme into the abseess cavity (1), The resistance of S. aureus and B, f>'agilis group to penicillin has been recognized for over 2 decades. However, 'rt recent years, a growing number of Organistns belong to the B. tnelaninogenicus group atid other black-pigtnent2d Bacteroides has been noticed to produce this enzyme (4, 14), These species are the predotninant Bacteroides present •n the oral flora and are, therefore, the Bacteroides most commonly recovered 'n anaerobic infections in and around the oral eavity (8). Penicillin was considered the drug of choice for the therapy of such infections becaues of the susceptibility of most oral pathogens; however, the growing resistance of these strains limits the use of this drug. Although periodotital therapy and surgical drainage are of primary importance, administradon of antimicrobial therapy is an essential part of the management of patients with serious periapical abscesses and their eomplications. The recovery of penicillin-resistant organisms in these patients may require the administration of antimicrobial agents also effective against these organistns. These include clindatnycin, chloramphenieol, earbenicillin, cefoxit'n, imipenem or the combination of a penicilhn and a beta-lactamase inhibitor
(3, 8), Metronidazole should be administered with an agent effective against the aerobic or facultadve streptoeocci. Acknowledgements
;
The authors acknowledge the efforts of the staff of Clinical Microbiology Laboratories at the Naval Medical Center, and the secretarial assistance of Minerva G. Barreiro. References 1, Brook I, Presence of beta-lactamase-producing bacteria and beta-lactamase activity in abscesses. Am J Clin Pathol 1986: 86: 97-101, 2, Brook I, Microbiology of abscesses of the head and neck in children, Ann Otol Rhinol Laryngol 1987: 96: 429-433, 3, Brook I, Pediatric anaerobic infections, diagtiosis and management. St, Louis: Mosby, 1989, 4, Brook I, Calhoun L, Yocum P Betalactamase-producing isolates of Bacteroides species from children, Antimicrob Agents Chemother 1980: 18: 164-166, 5, Brook I, Friedman EM, Intracranial complicatiotis of sinusitis in children: A sequella of periapical abscess, Ann Otol Rhinol Laryngol 1982: 91: 4 1 ^ 3 , 6, Brook L Grimm S, Kielich RB, Bacteriology of acute periapical abscess in children, J Endod 1981: 7: 378-380, 7, Chow AW, Roser SM, Brady FA, Orofacial odontogenic infections, Ann Intern Med 1978: 88: 392-402, 8, Fitiegold SM, Anaerobic bacteria in human disease. New York: Academic Press, 1977,
125
9, Heimdahl A, Von Konow L, Satoh T, Nord CE, Clinical appearance of orofacial infections of odontogenic origin in relation to microbiological fttidings, J Clin Microbioi 1985: 22: 299-302, 10, Hollin SA, Hayashi H, Gross SW, Intracranial abscesses of odontogenic origin. Oral Surg Oral Med Oral Pathol 1967: 23: 277-293, 11, Lennette EH, Balows A, Hausler WJ, Shadomy HJ, Manual of chnical microbiology, 4th edn, Washington, DC: Am Soc Microbioi, 1985, 12, Lewis MAO, MacFarlane TW, McGowan DA, Quantitative bacteriology of acute dento-alveolar abscesses, J Med Microbioi 1986: 21: 101-104, 13, Megran DW, Scheifele DW, Chow AW, Odontogenic infections, Ped Infect Dis 1984: 3: 258-265, 14, Murray PR, Rosenblatt JE, Penicillin resistatice and penicillinase production to clinical isolates of Bacteroides melanitiogenicus. Antimicrob Agents Chetnother 1977: 11: 605-608, 15, O'Callaghan CH, Morris A, Kirby SM, Shingler AH. Novel method for detection of beta-lactamase by tising a chromogenic cephalosporin substrate, Antimicrob Agents Chetnother 1: 283-288, 16, Oguntebi B, Slee AM, Tanzler JM, Langeland K, Predominant microflora associated with human dental periapical abscesses, J Clin Microbioi 1982: 15: 964-966, 17, Socransky SS, Manganiello SD, The oral microbiota of man from birth to senihty, J Periodontol 1971: 42: 485-496, 18, Sutter VL, Citron DM, Edelstein MAC, Finegold SM, Wadsworth anaerobic bacteriology manual, 4th edn, Belmont, CA: Star Publishitig, 1985,
Aerobic and anaerobic microbioiogy of periapicai abscess
llzhak Brook, Edith H. Frazier, IVIarlin E. Gher Naval Medical Center, Bethesda, Maryland, USA
orook I, Erazier EH, Gher ME, Aerobic atid anaerobic tnicrobiology of periapical abscess. Oral Micfobiol Ittmmttol 1991: 6: 123-125. Aspirates of pus from periapical abscesses in 39 patients were studied for aerobic and anaerobie bacteria. Bacterial growth was present in 32 specimens, A total of '8 bacterial isolates (55 anaerobic and 23 aerobic and facultative) were recovered, accounting for 2.4 isolates per specimen (1.7 anaerobic and 0,7 aerobic and lacultatives). Anaerobic bacteria only were present in 16 (50%) patients, aerobic and facultatives in 2 (6%), and mixed aerobic and anaerobic flora in 14 (44%). The predominant isolates were Bacteroides spp. (23 isolates, including 13 Bacteroides melatiinogenicus group). Streptococcus spp, (20), anaerobic cocci (18), and fusobacterium spp, (9). Beta-lactatnase-producing organistns were reeovered from / of the 21 (33%) specimens that were tested. This study highlights the polytnicrobial nature and itnportance of anaerobie bacteria in periapical abscess.
fhe flora associated with odontogenic infections is complex and generally reflect the combined infiuenee of the indigenous oral flora and the unique flora of the underlying conditions, Polymicrobtai aerobic-anaerobic flora was isolated also from cases of dentoalveolar abseesses (13). Studies done at the turn of the century of acute and chronic alveolar abscesses described the isolation of predominantly aerobic streptococci; however, fusiform bacilli and Bacteroides spp, were found in some abscesses, sometimes in pure culture. More recent studies report the isolation of a variety of anaerobes in periapical abscesses, including anaerobic cocci, anaerobic gram-negative bacilli, and anaerobic gram-positive bacilli (18), Since many of the anaerobes have been reelassified and renatned according to newer criteria for their identification, a more current evaluation of the incidence of recovery of anaerobie bacteria from this infeetion is desirable. Such a study tnay better show the frequeney of the recovery of anaerobes frotrt periapteal abscesses today and tnay also present the effect of these improvements on the recovery of these organisms.
he opinions and assertions contained herein ''re the private ones of the writer, and are not ° be construed as official or reflecting the J^ews of the Departtnent of Defense, the Navy Department, or the Naval Service at 'arge.
Material and methods
Between June 1975 and June 1985, 39 aspirates of periapical abscesses were processed for aerobic and anaerobic bacteria by the Clinical Microbioiogy Laboratories at the Naval Medical Center in Bethesda, MD, Bacterial growth was present in 32 instances. All the following data pertain only to these 32 patients. The mean patient's age was 43 years (range 8 years to 69 years) and 19 were tnales. Eleven of the patients received antitnicrobial therapy prior to sample collection. A beta-lactam-resistant penicillin (oxaeillin or dicloxacillin) was given to 6 patients, erythromycin to 3 and atnpieillin to 2, Cultures were obtained after cleansitig the oral mueous surface with povidone-iodine, by either direct needle aspiration of purulent contents or during surgical incision and drainage. The material was placed into a syringe that was imtnediately sealed and transported to the laboratory within 30 tnin, or by a swab that was dipped into the pus and introduced into anaerobie transport systetn (Port-A-Cul, BBL Microbiology Systetns, Coekeysville, MD), that was transported to the laboratory within 2h. For anaerobic bacteria, and specimen tnaterial was plated onto prereduced vitamin K,-enriched Brueella blood agar, an anaerobic blood plate containing colistin atid nalidixic aeid, and an enriched thioglycolate broth (contain-
Key words; periapical abscess; Bacteroides spp Itzhak Brook, M, D,, M, Sc, Armed Forces Radiobiology Research Institute, Bethesda, MD 20814-5145, USA Accepted for publication May 21, 1990
ing hemin and vitamin K,) (18), iticubated in GasPak jars (BBL Microbiology Systems), and examined at 48 and 96 h. Plates that showed growth were held utitil the organistns were processed and identified. All cultures that showed no growth were held for at least 7 d. Anaerobes were identified using the Minitek systetn (BBL Microbiology Systetns). In addition to these tests, other carbohydrate tests (Seott Laboratories, Fiskeville, RI) and gas hquid ehromatography (18) were performed as needed to identify the organisms. For aerobic bacteria, sheep blood (5%), chocolate and MacConkey's agar plates were inoculated at 37°C aerobically (MacConkey) and under 5% CO, (blood and chocolate), and examined at 24-48 h. Aerobic bacteria were identified using conventional methods (11). Beta-lactamase activity was determined on isolates reeovered from satnples usitig the chromogenic cephalosporin analog 87/312 methodology (15), Results
Anaerobic bacteria only were recovered in 16 (50%) specimens, aerobic or facultative baeteria only in 2 (6%) and mixed aerobic and anaerobic bacteria were recovered in 14 (44%), A total of 78 bacterial isolates were recovered, accounting for 2.4 isolates per speeitnen (1.7 anaerobes and 0,7 aerobes per specitnen) (Table 1). A total of 55 anaerobic bacteria were
124
Brook
bic isolates the most frequent ones were Streptococcus salivarius, and alpha-heAnaerobic bacteria Aerobic and facultative baeteria molytic streptococci. Staphylococeus aureus I Peptostreptococeus spp, Heimdahl et al. (9) evaluated 48 paStreptococcus milleri 3 Peptostreptococcus anaerobius Streptococcus mitior 1 Peptostreptocoecus micros tients with acute orofacial infections of Streptococcus satiguis 2 Peptostreptococeus prevotti odontogenic origin ineluditig periapical Streptococcus faecaiis 3 Peptostreptococeus intermedius abscess, A total of 174 anaerobic and 22 Alpha-hemolytic streptococcus 11 Propionbacterium acnes aerobic bacterial strains were isolated. Haemophilus parainjluenzae 2 Eubacterium lentum Anaerobic gram-negative rods and esVeillonella parvula pecially E. nucleatum were isolated more Eusobactertum spp, frequently from the patients with severe Eusobacterium nucleatum infections than from the patients with Eusobacteria mortiferum infections judged as mild. Bacieroides spp, Bacteroides fragilis Oguntebi et al. (16) studied 10 periBacteroides ovatus apical abscess in patients free of perioBacteroides meianinogenicus dontal disease. Mixed flora was idenBacteroides asaccharolyticus tified in all instatices. The most common Bacteroides intermedius isolates were F. nucleatum and StreptoBacteroides gingivalis coccus mitis, which were co-isolated in Bacieroides oralis 6 instances. Bacteroides oris-buccae In recent quantitative and qualitative Total 23 Total 55 study of 50 dentoalveolar abseess, Lewis et al, (12) recovered 3.3 isolates per abscess. Twenty (40%) abseesses conrecovered. No difference was noted in might have enabled the reeovery of tained anaerobes only, and 27 (54%) the recovery of organisms and the iso- some of the slow-growing organisms. It abseesses had a mixture of both aerobes lation of beta-lactamase producing bac- is also possible that obtaitiing concomi- and anaerobes. Three fourths of the isoteria between the patients that received tant cultures through a root canal might lates were strict anaerobes; the tnost antimicrobial agents and those that did have itnproved the recovery rate. How- commoti ones were Peptostreptococcus not. The predominant anaerobes recov- ever, such a procedure may be associ- spp., B, oralis and B. melatiinogenicus. ered were Bacteroides spp. (23 isolates), ated with contamination of the speci- The mean concentration of bacteria in anaerobic cocci (18 isolates), and Euso- mens by oral flora, since no mucosal each abscess was lO*''**''^. The mean bacterium spp, (9 isolates). A total of surface culture was taken after disinfec- eoncentration of anaerobic bacteria was 23 aerobic and facultative isolates were tion, the possibihty of contaminating JQ6.2+O,2 ^J^JJ QJ- facultatively anaerobic bacteria 105'±»l recovered. The predominant aerobic the specimens was not excluded. isolates were Streptococcus spp, (20 isoSerious cotnplications from periThe isolation of anaerobie bacteria lates). Only one consistent pattern of alone or mixed with aerobic and faculta- apical infections are relatively rare, concombinations was noted between tive organisms at that site is not surpris- sidering the enortnous numbers of inBacteroides spp, and Peptostreptococcus ing, since anaerobes are the predomi- feeted teeth that occur in the populaspp. (13 instances). nant organisms in the oropharynx, tion. However, in sotne cases, the Single bacterial isolates were recov- where they outnumber aerobes in the infection spreads to tissues in other porered in 3 instances. These included one ratio of 10 to 1 to 1000 to 1 (17), and fions of the oral cavity, causing submanisolate each of Bacteroides intermedius, are important pathogens in other snp- dibular or superficial sublingual abEusobacterium nucleatum, and Pepto- purative infeetion in and around the or- seesses; abscesses may be produced also in the submaxiliary triangle or in the opharynx (2). streptococcus micros, Beta-lactamase production was deThis study supports the reeovery of parapharyngeal or submasseterie spaee. In the maxilla, periapical infection tected in 8 isolates recovered from 7 of polymierobial flora in periapieal abthe 21 (33%) specimens that were seesses reported before (6, 7, 9, 12, 16). may affect only the soft tissues of the tested. These included the 2 members Chow et al. (7) recovered anaerobes in face. It may extend, however, to the of the Bacteroides fragilis group, all 3 all 4 periapical abscesses, in 3 also infratemporal space, including the sinuses, and then to the nervous system, Bacteroides meianinogenicus and one mixed with aerobic bacteria. isolate each of B. intertnedius, BacterIn a study of the bacteriology of peri- where it can cause serious complications oides asaecharolyticus and Staphylococ- apical abscess in 12 children (6), an- such as subdural enipyema, brain abcus aureus. aerobes were isolated in all patients. An- scess, or meningitis (3, 5, 8). aerobes were the only organism isolated The finding of anaerobic bacteria in in two thirds of the patients, and in the periapical abseesses is of importance beDiscussion rest they were mixed with aerobes. Of cause of the association of anaerobes This study illustrates the importance of the 53 anaerobie isolates the predomi- with many serious infections arising anaerobic bacteria in periapical abscess- nant ones were Bacteroides species, B, from dental foci, such as bacteremia, es, where these organisms were isolated meianinogenicus group, Bacteroides ora- endocarditis, sinusitis, menitigitis, subin 94% of the studied patients. It is lis, and Baeteroides ureolyticus, anaer- dural empyetna, brain abscess, and pulpossible that prolonging the incubation obie gram-positive cocci, fusobacteria, monary empyema (8, 10). of specimen to a period longer than 7 d and Actinomyces speeies. Of the 6 aeroOur data demonstrate the presence of Table 1. Bacterial isolates in 32 periapical abscesses
Microbiology of periapical abscesses
beta-lactamase-producing organisms in 33% of the tested abscess specimens. These organistns can survive penicillin therapy and may also protect penicillinsusceptible bacteria from penieillin by releasing the enzyme into the abseess cavity (1), The resistance of S. aureus and B, f>'agilis group to penicillin has been recognized for over 2 decades. However, 'rt recent years, a growing number of Organistns belong to the B. tnelaninogenicus group atid other black-pigtnent2d Bacteroides has been noticed to produce this enzyme (4, 14), These species are the predotninant Bacteroides present •n the oral flora and are, therefore, the Bacteroides most commonly recovered 'n anaerobic infections in and around the oral eavity (8). Penicillin was considered the drug of choice for the therapy of such infections becaues of the susceptibility of most oral pathogens; however, the growing resistance of these strains limits the use of this drug. Although periodotital therapy and surgical drainage are of primary importance, administradon of antimicrobial therapy is an essential part of the management of patients with serious periapical abscesses and their eomplications. The recovery of penicillin-resistant organisms in these patients may require the administration of antimicrobial agents also effective against these organistns. These include clindatnycin, chloramphenieol, earbenicillin, cefoxit'n, imipenem or the combination of a penicilhn and a beta-lactamase inhibitor
(3, 8), Metronidazole should be administered with an agent effective against the aerobic or facultadve streptoeocci. Acknowledgements
;
The authors acknowledge the efforts of the staff of Clinical Microbiology Laboratories at the Naval Medical Center, and the secretarial assistance of Minerva G. Barreiro. References 1, Brook I, Presence of beta-lactamase-producing bacteria and beta-lactamase activity in abscesses. Am J Clin Pathol 1986: 86: 97-101, 2, Brook I, Microbiology of abscesses of the head and neck in children, Ann Otol Rhinol Laryngol 1987: 96: 429-433, 3, Brook I, Pediatric anaerobic infections, diagtiosis and management. St, Louis: Mosby, 1989, 4, Brook I, Calhoun L, Yocum P Betalactamase-producing isolates of Bacteroides species from children, Antimicrob Agents Chemother 1980: 18: 164-166, 5, Brook I, Friedman EM, Intracranial complicatiotis of sinusitis in children: A sequella of periapical abscess, Ann Otol Rhinol Laryngol 1982: 91: 4 1 ^ 3 , 6, Brook L Grimm S, Kielich RB, Bacteriology of acute periapical abscess in children, J Endod 1981: 7: 378-380, 7, Chow AW, Roser SM, Brady FA, Orofacial odontogenic infections, Ann Intern Med 1978: 88: 392-402, 8, Fitiegold SM, Anaerobic bacteria in human disease. New York: Academic Press, 1977,
125
9, Heimdahl A, Von Konow L, Satoh T, Nord CE, Clinical appearance of orofacial infections of odontogenic origin in relation to microbiological fttidings, J Clin Microbioi 1985: 22: 299-302, 10, Hollin SA, Hayashi H, Gross SW, Intracranial abscesses of odontogenic origin. Oral Surg Oral Med Oral Pathol 1967: 23: 277-293, 11, Lennette EH, Balows A, Hausler WJ, Shadomy HJ, Manual of chnical microbiology, 4th edn, Washington, DC: Am Soc Microbioi, 1985, 12, Lewis MAO, MacFarlane TW, McGowan DA, Quantitative bacteriology of acute dento-alveolar abscesses, J Med Microbioi 1986: 21: 101-104, 13, Megran DW, Scheifele DW, Chow AW, Odontogenic infections, Ped Infect Dis 1984: 3: 258-265, 14, Murray PR, Rosenblatt JE, Penicillin resistatice and penicillinase production to clinical isolates of Bacteroides melanitiogenicus. Antimicrob Agents Chetnother 1977: 11: 605-608, 15, O'Callaghan CH, Morris A, Kirby SM, Shingler AH. Novel method for detection of beta-lactamase by tising a chromogenic cephalosporin substrate, Antimicrob Agents Chetnother 1: 283-288, 16, Oguntebi B, Slee AM, Tanzler JM, Langeland K, Predominant microflora associated with human dental periapical abscesses, J Clin Microbioi 1982: 15: 964-966, 17, Socransky SS, Manganiello SD, The oral microbiota of man from birth to senihty, J Periodontol 1971: 42: 485-496, 18, Sutter VL, Citron DM, Edelstein MAC, Finegold SM, Wadsworth anaerobic bacteriology manual, 4th edn, Belmont, CA: Star Publishitig, 1985,
