Multi-drug resistance and reduced susceptibility to ciprofloxacin among Salmonella enterica serovar Typhi isolates from the Middle East and Central Asia.

Typhoid fever is common in developing countries, with an estimated 120 million infections and 700 000 annual deaths, worldwide. Fluoroquinolones have been the treatment of choice for infection with multidrug-resistant (MDR) Salmonella enterica serovar Typhi (S. Typhi). However, alarming reports of fluoroquinolone-resistance and failure of typhoid fever treatment have recently been published. To determine the proportion of S. Typhi isolates with reduced susceptibility to ciprofloxacin (RSC) from six countries in the Middle East and Central Asia, 968 S. Typhi isolates collected between 2002 and 2007 from Egypt, Uzbekistan, Pakistan, Qatar, Jordan and Iraq were tested for antibiotic susceptibility to five antibiotics using the disc-diffusion method. MDR was defined as resistance to amicillin, chloramphenicol and trimethoprim-sulfamethoxazole. The E-test was employed to determine the MIC of ciprofloxacin only. Nalidixic acid resistance was evaluated as a marker for RSC. Interpretations were made according to CLSI guidelines. MDR strains were considerably more prevalent in Iraq (83%) and Pakistan (52%) compared with the other countries studied (13-52%). Nearly all isolates were susceptible (99.7%) to ceftriaxone. RSC was detected in a total of 218 isolates (22%), mostly from Iraq (54/59, 92%), Uzbekistan (98/123, 80%), Qatar (23/43, 54%) and Pakistan (31/65, 47%). Many of these (21%) were also MDR. Use of nalidixic acid resistance as an indicator for RSC was 99% sensitive and 98% specific. This study reinforces the need for routine antimicrobial susceptibility surveillance of enteric fever isolates and close review of current therapeutic policies in the region.

Capacity building of public health laboratories in Afghanistan: challenges and successes (2007-2011).

The continuing state of conflict and the resulting devastation of infrastructure have made Afghanistan exceptionally vulnerable to disease epidemics. The paper reports initiatives by the United States Naval Medical Research Unit No. 3 to promote capacity building in a number of key medical laboratories and enable the Afghans to detect emerging and re-emerging diseases of public health importance. Equipment, supplies and laboratory staff training were critical for disease diagnosis and fulfillment of obligations of the International Health Regulations 2005. Accordingly, many diseases outbreaks were recently identified, including avian and pandemic influenza, febrile illness, watery diarrhoea, jaundice and leishmaniasis. Clinical samples and disease vectors were collected for analysis, and microbial isolates were obtained for further characterization. The expanded range and enhanced accuracy of laboratory procedures have facilitated selected local laboratories to monitor, detect, identify, assess, contain and respond to public health threats. Nevertheless, policies of sustainability and infectious diseases control need continuous support and emphasis.

Capacity building of public health laboratories in Afghanistan: challenges and successes [2007-2011]

The continuing state of conflict and the resulting devastation of infrastructure have made Afghanistan exceptionally vulnerable to disease epidemics.The paper reports initiatives by the United States Naval Medical Research Unit No.3 to promote capacity building in a number of key medical laboratories and enable the Afghans to detect emerging and re-emerging diseases of public health importance.Equipment, supplies and laboratory staff training were critical for disease diagnosis and fulfilment of obligations of the International Health Regulations 2005.Accordingly, many diseases outbreaks were recently identified, including avian and pandemic influenza, febrile illness, watery diarrhoea, jaundice and leishmaniasis.Clinical samples and disease vectors were collected for analysis, and microbial isolates were obtained for further characterization.The expanded range and enhanced accuracy of laboratory procedures have facilitated selected local laboratories to monitor, detect, identify, assess, contain and respond to public health threats.Nevertheless, policies of sustainability and infectious diseases control need continuous support and emphasis

إن حالة الصراع المتواصل وما ينجم عنه من تدمير للبنية الأساسية قد جعلت أفغانستان عرضة بشكل كبير لأوبئة الأمراض. وتعمد هذه الورقة إلى عرض ما طرحته الوحدة الثالثة للبحوث الطبية للبحرية الأمريكية من مبادرات لتعزيز بناء القدرات في عدد من المختبرات الطبية الأساسية، ولتمكين الأفغان من اكتشاف الأمراض الناشئة والمنبعثة والتي تمثل أهمية للصحة العمومية. فالمعدات والإمدادات وتدريب العاملين في المختبرات تعد من الأمور الأساسية في تشخيص الأمراض، والوفاء بالالتزامات بموجب اللوائح الصحية الدولية 2005 . ومن ثم فقد تم مؤخرا اكتشاف العديد من فاشيات الأمراض بما فيها أنفلونزا الطيور والأنفلونزا الجائحية، والأمراض الحموية، والإسهال المائي، واليرقان، وداء الليشمانيات. وقد تم تجميع العينات السريرية ونواقل الأمراض بغرض تحليلها. وتم كذلك الحصول على المستفردات الميكروبية للتعرف بشكل أكبر على المزيد من خصائصها. وقد ساعد توسيع نطاق الإجراءات المختبرية وتعزيز دقتها، مختبرات محلية معينة على رصد واكتشاف وتحديد وتقييم واحتواء المخاطر التي تهدد الصحة العمومية ومجابهتها.ومع هذا فإن السياسات الخاصة بالاستدامة ومكافحة الأمراض المعدية بحاجة إلى مواصلة الدعم والتأكيد

La persistance du conflit ainsi que la destruction des infrastructures qui en résulte ont rendu l'Afghanistan exceptionnellement vulnérable aux épidémies.Le présent travail de recherche détaille les initiatives de l'Unité de recherche médicale de la marine des Etats-Unis d'Amérique [NAMRU-3]visant à promouvoir le renforcement des capacités de plusieurs laboratoires médicaux clés et à permettre aux Afghans de dépister des maladies émergentes et réémergentes qui sont importantes sur le plan de la santé publique.Les équipements, les fournitures et la formation du personnel de laboratoire étaient critiques pour le diagnostic des maladies et le respect des obligations découlant du Règlement sanitaire international [2005]. En conséquence, de nombreuses flambées épidémiques ont récemment été identifiées, notamment les grippes aviaire et pandémique, les maladies fébriles, les diarrhées aqueuses, l'ictère et la leishmaniose.Des échantillons cliniques ainsi que des vecteurs de maladie ont été collectés pour analyse, et des isolats microbiens ont été obtenus pour affiner la caractérisation.L'éventail élargi et la précision accrue des procédures de laboratoire ont permis aux laboratoires locaux sélectionnés de suivre, de dépister, d'identifier, d'évaluer, d'endiguer les menaces de santé publique et d'y répondre.Toutefois, les politiques visant à assurer la pérennité de ces capacités et la lutte contre les maladies infectieuses nécessitent un appui et un effort permanents

Comparative analysis of Shigella sonnei biotype g isolated from paediatric populations in Egypt, 1999-2005.

Strain characteristics of 51 Shigella sonnei isolates obtained from children seeking medical care (MC) and 48 isolates recovered during a prospective diarrhoea birth cohort (BC) study were compared. Biochemical characterization and antibiotic susceptibility testing determined that all S. sonnei isolates were biotype g and multidrug-resistant. Plasmid profiling identified 15 closely related patterns and XbaI pulsed-field gel electrophoresis confirmed the high degree of genetic similarity between isolates. All S. sonnei isolates harboured ipaH and class II integrase genes and 84∙3 and 80% of the MC and BC isolates, respectively carried the sen gene. Neither the class I integrase nor the set gene was detected. Our results indicate that S. sonnei isolates associated with severe diarrhoea were indistinguishable from those associated with mild diarrhoea. Additional genetic tests with greater discrimination might offer an opportunity to determine genetic differences within the globally disseminating biotype g clone.

Laboratory-based surveillance of patients with bacterial meningitis in Egypt (1998-2004).

Laboratory-based surveillance for bacterial meningitis was conducted in a network of infectious disease hospitals in Egypt to better understand the epidemiology of this infection. Healthcare and laboratory personnel were trained in basic surveillance and microbiologic processing of cerebrospinal fluid (CSF) specimens. All bacterial isolates from CSF were confirmed and tested for antimicrobial susceptibility. PCR testing was performed on a random subset of purulent, culture-negative CSF specimens. Of 11,070 patients who met criteria for the case definition, 843 (8%) were culture positive (42% positive for Streptococcus pneumoniae, 20% for Haemophilus influenzae serotype b, 17% for each of Neisseria meningitidis and Mycobacterium tuberculosis, and 6% for other bacteria). Of 1,784 (46%) CSF specimens tested by PCR, 232 (13%) were positive for the first three major pathogens. Of N. meningitidis isolates, 52% belonged to serogroup A, 35% to serogroup B, and 4% to serogroup W135. S. pneumoniae isolates comprised 46 different serotypes, of which 6B, 1, 19A, 23F, and 6A were the most predominant. The overall case-fatality rate for culture-positive cases was 26% and was highest among patients with M. tuberculosis (47%). Factors significantly associated with death (p < 0.05) included admission to rural hospitals, long prodromal period, referral from other hospitals, antibiotic treatment prior to admission, and clear CSF (<100 cells/mm3). Susceptibility to ampicillin and ceftriaxone was observed in 44 and 100% of H. influenzae serotype b isolates and in 52 and 94% of S. pneumoniae isolates, respectively. This surveillance highlights the significant mortality and morbidity associated with bacterial meningitis in Egypt. Decision makers need to review current treatment guidelines and introduce appropriate vaccines for prevention and control of the disease.

In vitro antibiotic susceptibility of Neisseria gonorrhoeae in Jakarta, Indonesia.

Antibiotic susceptibilities were determined for 122 Neisseria gonorrheae isolates obtained from 400 sex workers in Jakarta, Indonesia, and susceptibilities to ciprofloxacin, cefuroxime, cefoxitin, cefotaxime, ceftriaxone, chloramphenicol, and spectinomycin were found. All isolates were resistant to tetracycline. A number of the isolates demonstrated decreased susceptibilities to erythromycin (MIC >/= 1.0 microg/ml), thiamphenicol (MIC >/= 1.0 microg/ml), kanamycin (MIC >/= 16.0 microg/ml), penicillin (MIC >/= 2.0 microg/ml), gentamicin (MIC >/= 16.0 microg/ml), and norfloxacin (MIC = 0.5 microg/ml). These data showed that certain antibiotics previously used in the treatment of gonorrhea are no longer effective.

Isolation and antibiotic susceptibility of Salmonella, Shigella, and Campylobacter from acute enteric infections in Egypt.

While Campylobacter, Salmonella, and Shigella remain major contributors to acute enteric infections, few studies on these pathogens have been conducted in Egypt. From January 1986 to December 1993, 869 Salmonella, Shigella and Campylobacter strains were isolated from stool specimens from 6,278 patients, presenting to the Abbassia Fever Hospital, Cairo, Egypt, with acute enteric infections. Salmonella predominated, totalling 465 isolates, followed by Shigella with 258 isolates, and Campylobacter with 146 isolates. Of the Shigella isolates, 124 were Shigella flexneri, 49 were S. sonnei, 47 were S. dysenteriae (mainly serotype 1, 2, and 3), and 38 were S. boydii. Campylobacter spp. comprised 92 Campylobacter jejuni and 54 C. coli isolates. Isolation of Salmonella was highest during the months of February-March, June-July, and October-November, while that of Shigella was maximal from July to October. Isolation of Campylobacter increased during May-June and again during August-October. Although Salmonella was sensitive to amikacin, aztreonam, ceftriaxone, and nalidixic acid, it was, however, resistant to erythromycin, streptomycin, ampicillin, chloramphenicol, and tetracycline. Shigella (> 80%) was sensitive to amikacin, ceftriaxone, cephalothin, sulphamethoxazole-trimethoprim (except S. sonnei), aztreonam, and nalidixic acid. Resistance (> 50%) was noted only for ampicillin, chloramphenicol, and tetracycline. C. jejuni and C. coli were resistant to cephalothin, aztreonam, and streptomycin. Some of the above antibiotics were employed to characterize the Egyptian isolates, but did not have any clinical utility in the treatment of diarrhoea. Significant differences (p < 0.05) were observed in the resistance profiles of Shigella and Salmonella between late 1980s and early 1990s. The results suggest the use of fluoroquinolones or a third-generation cephalosporin as an empirical treatment of enteric diseases. However, alternative control strategies, including the aggressive development of broadly protective vaccines, may be more effective approaches to curbing morbidity and mortality due to acute enteric infections.

Phenotypic diversity of enterotoxigenic Escherichia coli strains from a community-based study of pediatric diarrhea in periurban Egypt.

No past studies of diarrhea in children of the Middle East have examined in detail the phenotypes of enterotoxigenic Escherichia coli (ETEC) strains, which are important pathogens in this setting. During a prospective study conducted from November 1993 to September 1995 with 242 children under 3 years of age with diarrhea living near Alexandria, Egypt, 125 episodes of diarrhea were positive for ETEC. ETEC strains were available for 98 of these episodes, from which 100 ETEC strains were selected and characterized on the basis of enterotoxins, colonization factors (CFs), and O:H serotypes. Of these representative isolates, 57 produced heat-stable toxin (ST) only, 34 produced heat-labile toxin (LT) only, and 9 produced both LT and ST. Twenty-three ETEC strains expressed a CF, with the specific factors being CF antigen IV (CFA/IV; 10 of 23; 43%), CFA/II (5 of 23; 22%), CFA/I (3 of 23; 13%), PCFO166 (3 of 23; 13%), and CS7 (2 of 23; 9%). No ETEC strains appeared to express CFA/III, CS17, or PCFO159. Among the 100 ETEC strains, 47 O groups and 20 H groups were represented, with 59 O:H serotypes. The most common O serogroups were O159 (13 strains) and O43 (10 strains). O148 and O21 were each detected in five individual strains, O7 and O56 were each detected in four individual strains, O73, O20, O86, and O114 were each detected in three individual strains, and O23, O78, O91, O103, O128, and O132 were each detected in two individual strains. The most common H serogroups were H4 (16 strains), 12 of which were of serogroup O159; H2 (9 strains), all of which were O43; H18 (6 strains); H30 (6 strains); and H28 (5 strains); strains of the last three H serogroups were all O148. Cumulatively, our results suggest a high degree of clonal diversity of disease-associated ETEC strains in this region. As a low percentage of these strains expressed a CF, it remains possible that other adhesins for which we either did not assay or that are as yet undiscovered are prevalent in this region. Our findings point out some potential barriers to effective immunization against ETEC diarrhea in this population and emphasize the need to identify additional protective antigens commonly expressed by ETEC for inclusion in future vaccine candidates.

Differentiation of Campylobacter isolates on the basis of sensitivity to boiling in water as measured by PCR-detectable DNA.

Differential sensitivity for the release of PCR-detectable genomic DNA upon boiling in water is reported for 45 Campylobacter jejuni and Campylobacter coli strains isolated in Egypt. All of the strains released PCR-detectable DNA when treated with proteinase K and sodium dodecyl sulfate. When DNA was extracted from these strains by boiling in water, nine (20%) of the strains were PCR negative or resistant to boiling, suggesting the presence of boiling-sensitive and boiling-resistant phenotypes.

Evaluation of antibodies reactive with Campylobacter jejuni in Egyptian diarrhea patients.

Serum and stool samples were collected from 128 individuals: 96 diarrhea patients and 32 apparently healthy controls. Stool specimens were cultured for enteric bacterial pathogens, while sera were screened by enzyme-linked immunosorbent assay for Campylobacter jejuni-reactive antibodies. Of 28 diarrhea patients who demonstrated C. jejuni-reactive antibodies (titers, > 100), 14 were culture positive for this organism. The 32 healthy controls showed significantly lower antibody titers (P < 0.05) with the exception of 10 subjects who were culture positive for C. jejuni and had reactive immunoglobulin M (IgM) (6 subjects) and IgG (7 subjects). IgA was not detected in those 10 individuals (asymptomatic). Avidity was expressed as the thiocyanate ion concentration required to inhibit 50% of the bound antibodies. The avidity was higher in symptomatic patients than asymptomatic healthy controls. IgG was less avid (0.92 M) compared to IgM (0.1 M) and IgA (1.1 M), with no correlation between antibody titer and avidity. However, the thiocyanate ion concentration required for the complete inhibition of IgG (5 M)-bound antibodies was higher than that of IgA (2 M) and IgM (3 M). This study also shows that C. jejuni antibodies were variably cross-reactive with Escherichia coli, Shigella flexneri, Shigella sonnei, and Neisseria meningitidis in addition to Campylobacter coli and Campylobacter rectus.

Enteropathogens associated with diarrhea among military personnel during Operation Bright Star 96, in Alexandria, Egypt.

This study investigated the microbial causes of diarrheal disease among U.S. troops deployed near Alexandria, Egypt, during October 1995. Bacterial causes associated with 19 cases of diarrhea included: enterotoxigenic Escherichia coli (ETEC), 42% (21% heat-stable, 11% heat-labile, and 11% heat-stable/ heat-labile producers); enteropathogenic E. coli (5.3%); and enteroadherent E. coli (42%). Four cases of diarrhea were associated with enteroaggregative E. coli based on probe analysis for enteroaggregative heat-stable enterotoxin 1. Protozoan causes included; Entamoeba histolytica (11%), E. hartmanni (5%), E. nana (5%), Blastocystis hominis (5%), Chilomastix mesnili (11%), Dientamoeba fragilis (5%), Entamoeba coli (5%), and Cryptosporidium (5%). Shigella, Aeromonas, Plesiomonas, Vibrio, Campylobacter, and Salmonella were not detected. Of the eight ETEC cases, one was colonization factor antigen (CFA)/I only, one was both CFA/I and CFA/III, three were CFA/II, two were CFA/IV, and two were CFA-negative. Antibiograms of the ETEC and enteroadherent E. coli strains showed that all isolates were susceptible to norfloxacin, ciprofloxacin, and nalidixic acid but resistant to ampicillin, tetracycline, chloramphenicol, and sulfamethoxazole.

Rapid and sensitive detection of Campylobacter spp. from chicken using the polymerase chain reaction.

The polymerase chain reaction (PCR) using a target region in the flaA gene of C. coli VC167 flagellin was used to detect Campylobacter spp. in chicken without an enrichment culture. DNA extracted from 79 cloacal swabs from broiler chickens gave an amplification signal in the 450-bp region upon PCR. DNA extracted from 9 enteric and 6 non-enteric organisms included in the assay as negative controls failed to hybridize with the probe. Direct plating of all cloacal specimens on Campylobacter blood agar plates did not yield any growth. The PCR assay was sensitive enough to detect between 35-120 bacteria per PCR and thus provide a basis for detecting Campylobacter spp. in poultry.

Detection of enterotoxigenic Escherichia coli, Shigella and Campylobacter spp. by multiplex PCR assay.

Three oligonucleotide primers were used in a polymerase chain reaction (PCR) assay for the simultaneous amplification of regions of the invasive plasmid antigen (ipaH) of Shigella spp., flagellin gene (flaA) of Campylobacter spp., and heat-labile enterotoxin (LT) of enterotoxigenic Escherichia coli (ETEC). The multiplex assay was performed using DNA extracted by a chaotropic method directly from diarrhoeal stools. The diagnostic efficacy of the assay was analyzed by agarose gel electrophoresis. This assay shows a novel approach for the diagnosis of diarrhoea caused by Shigella spp., ETEC, and Campylobacter spp.

Prevalence of antibiotic resistance among Egyptian Salmonella typhi strains.

This report describes the resistance of 537 Salmonella typhi isolates identified in Egypt between 1990-1994. Results indicated a high isolation rate for multiple resistant S. typhi (> 71% of isolates collected in 1992-93), particularly to the three standard drug regimens of the clinically relevant antibiotics; ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole. This adds to the complexity and difficulty of treating infections caused by these organisms. Resistance of S. typhi was associated with a transferable 120 MD plasmid. The organism was sensitive to amikacin, aztreonam, cephalothin, ceftriaxone, gentamicin and nalidixic acid, suggesting the use of aztreonam and ceftriaxone as alternative therapeutic drugs for the treatment of multidrug-resistant S. typhi. These results may provide a clinically useful evaluation of the spread and acquisition of resistance among S. typhi strains in Egypt.

Colonization factors of enterotoxigenic E. coli (ETEC) from residents of northern Egypt.

Infection caused by enterotoxigenic Escherichia coli (ETEC) poses a serious health problem to children in developing countries. Colonization of the small intestinal mucosa by ETEC strains is mediated by antigenically specific fimbriae, also known as colonization factor antigens (CFA). The importance of this study arises from reports that active and passive immunization with ETEC strains harboring CFAs induced protective immunity against diarrhea in animal models with preformed antibodies. In humans, ETEC containing CFA/I, II, III and IV have been identified. The aim of this study was to define CFAs of ETEC isolated in Alexandria, Egypt. One hundred and seven ETEC isolates from 132 human residents in Alexandria, Egypt were isolated during a birth cohort study. ETEC isolates were screened for heat labile (LT) and heat stable (ST) toxins using a 32P oligonucleotide hybridization probe and a GM1 ELISA. These isolates were examined using monoclonal antibodies against CFA/I, II, III, IV, and against the putative colonization antigens PCF0159 and PCF0166, CS 7 and CS 17. CFAs were found in 48% of ETEC strains. CFA/I was found in 18% of the strains, CFA/II in 10% and CFA/IV in 14%. CFA III was not found. All fifteen strains expressing CFA/IV expressed CS6 and produced ST. CFA/IV was not found in non-ST producing strains, while CFA/I was absent in ST-only producing strains.

A survey of enteropathogens among United States military personnel during Operation Bright Star '94, in Cairo, Egypt.

Acute gastroenteritis is a potential cause of substantial morbidity in U.S. military personnel during deployment. This study was conducted to evaluate enteric pathogens associated with diarrhea in a U.S. military population on deployment in Cairo, Egypt, during November 1993. Enteric pathogens found to be associated with cases of diarrhea included: enterotoxigenic Escherichia coli (ETEC), 27% (22% heat-stable [ST], 3% heat-labile [LT], and 2% ST/LT producers); Campylobacter spp., 3%; and Salmonella spp. 3%. Other enteric pathogens, namely Shigella, Aeromonas, Plesiomonas, Vibrio spp., Bacillus cereus, and enteric parasites, were not found in any of the 36 patients. Of the 8 patients who were ETEC-positive, three expressed colonization factor antigens (CFA)/II, and two expressed putative colonization factor antigen (PCF) 0159. All of the latter isolates produced ST. ETEC with different surface protein antigens were found to have surface hydrophobicity in the range of 0.2 M to greater than 2.0 M. Plasmid profiles of the ETEC strains showed no correlation with toxin production. In vitro susceptibility testing of the ETEC strain showed that 32% of the strains were resistant to three or more antimicrobial agents, whereas 24% showed 100% susceptibility. The enteropathogens tested were susceptible to norfloxacin, ciprofloxacin, and nalidixic acid, suggesting that the quinolones might be useful for the treatment of diarrheic patients.

Impaired bactericidal activity of PMN from two brothers with necrotizing ulcerative gingivo-periodontitis.

The purpose of this study was to investigate the pathogenesis of necrotizing ulcerative gingivo-periodontitis (ANUP) diagnosed in two brothers, age 9 (ANUP1) and 14 (ANUP2) from rural Egypt. Complete blood count, differential and blood chemistry were within normal limits for both brothers and they were not malnourished. The phagocytosis and killing function of their polymorphonuclear leukocytes (PMN) towards four bacterial species were assessed using a fluorochrome microassay. The selection of bacterial species was based on preliminary microbiological results in early onset periodontitis in Egypt. Fluorochrome-labeled Prevotella intermedia, Peptostreptococcus micros, Campylobacter rectus, and Porphyromonas gingivalis were pre-opsonized with ANUP serum and added to PMN from both ANUP patients, as well as PMN from three sex-matched and two sex- and age-matched healthy Egyptian control (CTL) subjects. We found significant depressions (P < 0.05) in PMN phagocytosis and killing of C. rectus and P. intermedia by ANUP1 and ANUP2, when compared to all CTL PMN. An assessment of the Gram-negative subgingival microflora present in both ANUP patients (in colony forming unit percent of total CFU recovered) (CFU %) revealed the presence of P. intermedia (ANUP1, 41.7 CFU %; ANUP2, 14.8 CFU %), Fusobacterium nucleatum (ANUP1, 3.6 CFU %; ANUP2, 48.1 CFU %), and Veillonella spp. (ANUP1, 18.2 CFU %; ANUP2, 18.5 CFU %). Spirochetes were also observed in cytocentrifuged, Gram-stained plaque from both ANUP patients. The predominant Gram-positive bacterial species recovered from both NUG1 and NUG2 was Streptococcus morbillorum.

Use of the Syrian golden hamster for the induction of intraoral abscesses by sutures contaminated with human subgingival plaque.

Analysis of normal oral flora in 150 cheek pouches of hamsters (Mesocricetus auratus) defined the microbial working environment and demonstrated the absence of human oral black-pigmented bacteria. Silk sutures saturated with Porphyromonas gingivalis, Prevotella intermedia or subgingival plaque were used to close wounds made in hamster's cheek pouches. Abscesses were formed when sutures had solitary P. gingivalis or other bacteria mixed with P. gingivalis or when P. intermedia was mixed with other bacteria besides P. gingivalis. A concentration of black-pigmented bacteria emanating from 3 x 10(5) colony-forming units/inoculum was required for abscess formation. Six abscesses (14.3%) were developed in association with the presence of other odontopathic bacteria, primarily Fusobacterium nucleatum and Actinomyces viscosus. The hamster cheek pouch with iatrogenic wounds closed with plaque-impregnated sutures is a novel and effective model to study the pathology of wound infections and virulence of human subgingival organisms.

Microbiological evaluation of periapical infections in Egypt.

This study identifies and correlates proportions of bacteria in periapically involved anterior teeth of 85 adult Egyptian patients. Affected sites were free from caries and periodontal disease but had a history of trauma. The mean number of component bacterial species per specimen was 3.1. Anaerobic bacteria were the dominant flora present in specimen cultures, comprising 73% (190/259) of cultivable bacteria. The most frequently isolated organisms were Eubacterium species (68%), black-pigmented Bacteroides (56%), Streptococcus morbillorum (47%) and non-pigmented Bacteroides (37%). These organisms also showed the highest proportional values relative to total cultivable bacteria. The mean percentages of total viable counts of these isolates were 19.0%, 14.1%, 18.0% and 15.5%, respectively. Statistical analysis of data revealed a significant negative correlation between S. morbillorum and Bacteroides species.

Comparative microbiological and immunological studies of subgingival dental plaque from man and baboons.

Baboons may be useful as animal models for the study of human oral diseases and infections. They are closely related to man anatomically, physiologically, and phylogenetically. Plaque and gingival indices were relatively low in 18 baboons (Papio anubis). The mean scores ranged between 0.62 +/- 0.29 and 0.37 +/- 0.20, respectively. Gram-positive and Gram-negative cocci comprised 27.0 +/- 32.4 and 3.1 +/- 7.5% of the total viable counts in the dental plaque samples. Black-pigmented Bacteroides formed about 1.9 +/- 5.9% of the bacterial population in the samples. Anaerobic Gram-negative bacilli were found in 73.2% of the samples and averaged 19.2 +/- 26.3% of the total recovered flora. Species of the oral Actinomyces and other Gram-positive rods found in humans were not isolated. The composition of the oral flora in baboons appeared to be significantly different from that of man. Isolates of F. nucleatum, L. buccalis, and B. intermedius from the two mammals were biochemically similar, but were distinguishable by analysis with antibody, both by precipitin lines and/or differences between homologous and heterologous titers.