Exploring the arthritogenicity of Streptococcus dysgalactiae subspecies equisimilis.

BACKGROUND: During the past decades, Streptococcus dysgalactiae subspecies equisimilis (SDSE) has been increasingly recognized as an important human pathogen. Osteoarticular infections is one of the predominant disease manifestations of SDSE, but the pathogenetic rationale for its arthritogenicity has yet to be unravelled. We aimed to explore if the rising incidence of osteoarticular infections caused by this pathogen in our region emanated from clonal expansion of strains with enhanced tropism for bone and joint tissue components or orthopaedic implants. RESULTS: Twenty-nine SDSE-isolates associated with osteoarticular infections were retrospectively identified. Their genomic content and affinity for fibronectin, collagen and stainless steel were compared to 24 temporally and geographically matched SDSE blood culture isolates obtained from patients without bone or joint infections. Despite a thorough genetic and phenotypic dissection, neither the presence or absence of any single gene, nor the binding abilities of the SDSE isolates, were predictive of clinical entity. SNP analysis revealed a heterogenous population, and a correlation between phylogenetic relationships and disease manifestation was not evident. However, we identified a strong concordance between phenotypic binding abilities and genetic variations in the pilus-region, also denoted as the FCT-region (Fibronectin binding, Collagen binding and T-antigen). This observation could be related to the ample and varied repertoire of putative adhesins residing within this region, including proteins predicted to adhere to fibronectin and collagen, as well as fibrinogen. CONCLUSIONS: SDSE strains associated with osteoarticular infections do not emanate from subpopulation characterized by distinct genetic or phenotypic traits. The genetic architecture of the pilus region was predictive of the adhesive properties of the SDSE-isolates, but its role in tissue tropism needs further investigation. To the best of our knowledge, this is the first comprehensive characterization of the genetic landscape of the SDSE pilus region.

Temporal trends of ß-haemolytic streptococcal osteoarticular infections in western Norway.

BACKGROUND: Beta-haemolytic streptococci are important contributors to the global burden of osteoarticular infections (OAI). Knowledge on the disease traits specific for streptococcal OAI, however, remains scarce. We wished to explore temporal trends of OAI caused by Group A Streptococci (GAS), Group B Streptococci (GBS) and Group C and G Streptococci (GCGS), and furthermore, to describe the associated host and pathogen characteristics. METHODS: All cases of microbiologically verified ß-haemolytic streptococcal OAI in Health Region Bergen, Norway, in the period 1999-2013 were retrospectively identified. Clinical data were extracted from medical records. Microbial isolates were submitted to antibiotic susceptibility testing and molecular typing. RESULTS: A total of 24 GAS, 45 GBS and 42 GCGS acute OAI were identified. The cumulative incidence of GCGS OAI, but not GAS or GBS OAI, increased significantly from the first to the last 5-year period (IRR 5.7, p = 0.0003), with the annual incidence peaking at 1.9/100 000 in 2013. GAS OAI generally produced the most acute and severe clinical presentation, whereas GBS and GCGS predominantly affected the elderly, and were significantly associated with the presence of host risk factors of systemic and focal origin, respectively. CONCLUSIONS: We found a significantly increasing incidence of GCGS OAI, likely related to the presence of host susceptibility factors, including prosthetic material and pre-existing joint disease. With an increasing application of therapeutic and diagnostic bone and joint procedures, the rising trend of OAI caused by GCGS is likely to continue. Sustained epidemiological attentiveness to GCGS seems warranted.

Endogenous fungal endophthalmitis caused by Cladophialophora devriesii: report of a case and literature review.

PURPOSE: To report a case of endogenous endophthalmitis caused by the dematiaceous fungus Cladophialophora devriesii. METHODS: Observational case report and literature review. CASE PRESENTATION: A 73-year-old female with a history of chronic obstructive pulmonary disease presented with a red and painful left eye. Examination revealed anterior segment inflammation and vitritis, indicative of endophthalmitis. She underwent core vitrectomy and intravitreal injection of vancomycin and amphotericin B. The vitreous sample showed inflammatory cells and fungal hyphae, and systemic amphotericin B and itraconazole were commenced for fungal endophthalmitis. Targeted amplification of the sample for bacterial DNA (V2-V3 region of 16 S rDNA) was negative, but fungal DNA targets (ITS1 and ITS2) were present, and their sequences were consistent with Cladophialophora devriesii. Phenotypic characterisation and sequencing of ITS1 and ITS2, carried out on cultured fungus from the sample, also revealed Cladophialophora devriesii. She received repeated intravitreal injections of voriconazole, and based on the antifungal susceptibility results, her systemic medication was changed to posaconazole. After 12 months, the eye showed no signs of inflammation, and posaconazole therapy was discontinued. After 3 months without antifungal medication, the inflammation recurred, and she was restarted on antifungal therapy for an additional 20 months. Another recurrence occurred 3 months after discontinuation of treatment, and a repeat vitreous sample confirmed the presence of Cladophialophora devriesii. She was started on isavuconazole, but developed seclusio pupillae and painful secondary glaucoma. Due to the duration and severity of the infection, the eye was enucleated. Histopathology revealed persistent fungal elements at the ciliary processes and the posterior lens surface. CONCLUSIONS: This second reported case of endogenous endophthalmitis caused by Cladophialophora devriesii illustrates the role of vitreous sampling and molecular methods in diagnosis and treatment of fungal endophthalmitis. Despite early diagnosis and prolonged local and systemic antifungal therapy, it was not possible to achieve long-term control of the fungal infection.

Consistent Biofilm Formation by Streptococcus pyogenes emm 1 Isolated From Patients With Necrotizing Soft Tissue Infections.

OBJECTIVES: Biofilm formation has been demonstrated in muscle and soft tissue samples from patients with necrotizing soft tissue infection (NSTI) caused by Streptococcus pyogenes, but the clinical importance of this observation is not clear. Although M-protein has been shown to be important for in vitro biofilm formation in S. pyogenes, the evidence for an association between emm type and biofilm forming capacity is conflicting. Here we characterize the biofilm forming capacity in a collection of S. pyogenes isolates causing NSTI, and relate this to emm type of the isolates and clinical characteristics of the patients. METHODS: Bacterial isolates and clinical data were obtained from NSTI patients enrolled in a multicenter prospective observational study. Biofilm forming capacity was determined using a microtiter plate assay. RESULTS: Among 57 cases, the three most frequently encountered emm types were emm1 (n = 22), emm3 (n = 13), and emm28 (n = 7). The distribution of biofilm forming capacity in emm1 was qualitatively (narrow-ranged normal distribution) and quantitatively (21/22 isolates in the intermediate range) different from other emm types (wide ranged, multimodal distribution with 5/35 isolates in the same range as emm1). There were no significant associations between biofilm forming capacity and clinical characteristics of the patients. CONCLUSIONS: The biofilm forming capacity of emm1 isolates was uniform and differed significantly from other emm types. The impact of biofilm formation in NSTI caused by S. pyogenes on clinical outcomes remains uncertain.

Case Report: Whole-Genome Sequencing of Serially Collected Haemophilus influenzae From a Patient With Common Variable Immunodeficiency Reveals Within-Host Evolution of Resistance to Trimethoprim-Sulfamethoxazole and Azithromycin After Prolonged Treatment With These Antibiotics.

We report within-host evolution of antibiotic resistance to trimethoprim-sulfamethoxazole and azithromycin in a nontypeable Haemophilus influenzae strain from a patient with common variable immunodeficiency (CVID), who received repeated or prolonged treatment with these antibiotics for recurrent respiratory tract infections. Whole-genome sequencing of three longitudinally collected sputum isolates during the period April 2016 to January 2018 revealed persistence of a strain of sequence type 2386. Reduced susceptibility to trimethoprim-sulfamethoxazole in the first two isolates was associated with mutations in genes encoding dihydrofolate reductase (folA) and its promotor region, dihydropteroate synthase (folP), and thymidylate synthase (thyA), while subsequent substitution of a single amino acid in dihydropteroate synthase (G225A) rendered high-level resistance in the third isolate from 2018. Azithromycin co-resistance in this isolate was associated with amino acid substitutions in 50S ribosomal proteins L4 (W59R) and L22 (G91D), possibly aided by a substitution in AcrB (A604E) of the AcrAB efflux pump. All three isolates were resistant to aminopenicillins and cefotaxime due to TEM-1B beta-lactamase and identical alterations in penicillin-binding protein 3. Further resistance development to trimethoprim-sulfamethoxazole and azithromycin resulted in a multidrug-resistant phenotype. Evolution of multidrug resistance due to horizontal gene transfer and/or spontaneous mutations, along with selection of resistant subpopulations is a particular risk in CVID and other patients requiring repeated and prolonged antibiotic treatment or prophylaxis. Such challenging situations call for careful antibiotic stewardship together with supportive and supplementary treatment. We describe the clinical and microbiological course of events in this case report and address the challenges encountered.

Age specific aetiological agents of diarrhoea in hospitalized children aged less than five years in Dar es Salaam, Tanzania.

BACKGROUND: This study aimed to determine the age-specific aetiologic agents of diarrhoea in children aged less than five years. The study also assessed the efficacy of the empiric treatment of childhood diarrhoea using Integrated Management of Childhood Illness (IMCI) guidelines. METHODS: This study included 280 children aged less than 5 years, admitted with diarrhoea to any of the four major hospitals in Dar es Salaam. Bacterial pathogens were identified using conventional methods. Enzyme Linked Immunosorbent Assay (ELISA) and agglutination assay were used to detect viruses and intestinal protozoa, respectively. Antimicrobial susceptibility was determined using Kirby-Bauer disk diffusion method. RESULTS: At least one of the searched pathogens was detected in 67.1% of the cases, and mixed infections were detected in 20.7% of cases. Overall, bacteria and viruses contributed equally accounting for 33.2% and 32.2% of all the cases, respectively, while parasites were detected in 19.2% patients. Diarrhoeagenic Escherichia coli (DEC) was the most common enteric pathogen, isolated in 22.9% of patients, followed by Cryptosporidium parvum (18.9%), rotavirus (18.1%) and norovirus (13.7%). The main cause of diarrhoea in children aged 0 to 6 months were bacteria, predominantly DEC, while viruses predominated in the 7-12 months age group. Vibrio cholerae was isolated mostly in children above two years. Shigella spp, V. cholerae and DEC showed moderate to high rates of resistance to erythromycin, ampicillin, chloramphenicol and tetracycline (56.2-100%). V. cholerae showed full susceptibility to co-trimoxazole (100%), while DEC and Shigella showed high rate of resistance to co-trimoxazole; 90.6% and 93.3% respectively. None of the bacterial pathogens isolated showed resistance to ciprofloxacin which is not recommended for use in children. Cefotaxime resistance was found only in 4.7% of the DEC. CONCLUSION: During the dry season, acute watery diarrhoea is the most common type of diarrhoea in children under five years in Dar es Salaam and is predominantly due to DEC, C. parvum, rotaviruses and noroviruses. Constant antibiotic surveillance is warranted as bacteria were highly resistant to various antimicrobial agents including co-trimoxazole and erythromycin which are currently recommended for empiric treatment of diarrhoea.

Identification of Streptococcus dysgalactiae using matrix-assisted laser desorption/ionization-time of flight mass spectrometry; refining the database for improved identification.

Matrix-assisted laser desorption/ionization time of flight (MALDI-ToF) has revolutionized bacterial identification. However, the phylogenetic resolution is still insufficient for discerning several ß-haemolytic streptococcal species. We aimed to improve the diagnostic performance of MALDI-ToF through manual curation of the reference spectra in Brukers Compass Library DB-7854. Before intervention, only 133 out of 217 (62%) Streptococcus dysgalactiae isolates were successfully identified to the species level, 83 isolates were identified to the genus level as either S. dysgalactiae, S. pyogenes or S. canis, and one S. dysgalactiae isolate was wrongly identified as S. canis. All 109 S. canis isolates were successfully identified to the species level. Removal of three reference spectra from the database significantly improved the identification of S. dysgalactiae to 94%, without compromising identification of S. canis. This illustrates the advantage of refinement of the reference database in order to improve the analytic precision of MALDI-ToF.

Two unusual cases of severe soft tissue infection caused by Streptococcus dysgalactiae subsp. equisimilis.

We present two cases of invasive infection caused by Streptococcus dysgalactiae subsp. equisimilis, one that showed rapidly developing necrotizing fasciitis in a previously healthy man and one that showed severe cellulitis and septic shock even though the bacterium possessed a mutated emm gene, predicted to encode a truncated M protein.

Clinical, microbiological and molecular characteristics of six cases of group A streptococcal meningitis in western Norway.

Meningitis is a rare clinical manifestation of invasive group A streptococcal (iGAS) disease. Clinical, microbiological and molecular characteristics of 6 consecutive cases of GAS meningitis treated in Haukeland University Hospital in the period 2004-2009 are described. All 6 patients had a primary upper respiratory tract infection, with subsequent mastoiditis in 5, subdural effusions in 2, and cerebral abscess in 1. Five patients needed surgical treatment (myringotomy, craniotomy or mastoidectomy). All patients were treated with a beta-lactam antibiotic in combination with rifampicin. The course was complicated in all cases, and 1 patient died. Three of the bacterial isolates were of the sequence type emm1.0 and they shared the same superantigen gene profile (speA, speG, speJ, smeZ). The remaining 3 isolates belonged to sequence types emm 3.1, emm6.4 and emm12.0. Deletions in emm genes were observed. This report describes the severe and complicated course of GAS meningitis and its management, often requiring surgical intervention.

Emerging Threat of Antimicrobial Resistance in ß-Hemolytic Streptococci.

Highly variable resistance rates to erythromycin and clindamycin have been reported in the ß-hemolytic streptococcal species Streptococcus pyogenes, Streptococcus agalactiae, and Streptococcus dysgalactiae, depending on geographic and temporal context. In the present study we aimed to examine the longitudinal trends of antimicrobial resistance in these three species in a northern European setting. Furthermore, we used whole genome sequencing to identify resistance determinants and the mobile genetic elements involved in their dissemination, as well as elucidate phylogenetic relationships. All cases of invasive ß-hemolytic streptococcal diseases in Health Region Bergen, western Norway, in the period 2004 to 2018 were retrospectively identified, comprising 271, 358, and 280 cases of S. pyogenes, S. agalactiae, and S. dysgalactiae, respectively. Antimicrobial susceptibility testing revealed a gradual but significant increase in erythromycin and clindamycin resistance for S. agalactiae and S. dysgalactiae during the study period. Whole genome sequencing of the erythromycin and clindamycin resistant bacterial population revealed a substantial phylogenetic diversity in S. agalactiae and S. dysgalactiae. However, the mobile genetic elements harboring the resistance determinants showed remarkable intra- and interspecies similarities, suggesting a dissemination of antimicrobial resistance predominantly through conjugative transfer rather than clonal expansion of resistant strains in these two species. Conversely, antimicrobial resistance in S. pyogenes remained low, apart from a transient outbreak of a clindamycin and erythromycin resistant emm11/ST403-clone in 2010-2012. Increased epidemiological attentiveness is warranted to monitor the emerging threat of antimicrobial resistance in ß-hemolytic streptococci, particularly in S. agalactiae and S. dysgalactiae.

Role of Horizontal Gene Transfer in the Development of Multidrug Resistance in Haemophilus influenzae.

Haemophilus influenzae colonizes the respiratory tract in humans and causes both invasive and noninvasive infections. Resistance to extended-spectrum cephalosporins in H. influenzae is rare in Europe. In this study, we defined acquired resistance gene loci and ftsI mutations in multidrug-resistant (MDR) and/or PBP3-mediated beta-lactam-resistant (rPBP3) H. influenzae strains, intending to understand the mode of spread of antibiotic resistance determinants in this species. Horizontal transfer of mobile genetic elements and transformation with resistance-conferring ftsI alleles were contributory. We found one small plasmid and three novel integrative conjugative elements (ICEs) which carry different combinations of resistance genes. Demonstration of transfer and/or ICE circular forms showed that the ICEs are functional. Two extensively MDR genetically unrelated H. influenzae strains (F and G) from the same geographical region shared an identical novel MDR ICE (Tn6686) harboring bla TEM-1, catA2-like, and tet(B). The first Nordic case of MDR H. influenzae septicemia, strain 0, originating from the same geographical area as these strains, had a similar resistance pattern but contained another ICE [Tn6687 with bla TEM-1, catP and tet(B)] with an overall structure quite similar to that of Tn6686. Comparison of the complete ftsI genes among rPBP3 strains revealed that the entire gene or certain regions of it are identical in genetically unrelated strains, indicating horizontal gene transfer. Our findings illustrate that H. influenzae is capable of acquiring resistance against a wide range of commonly used antibiotics through horizontal gene transfer, in terms of conjugative transfer of ICEs and transformation of chromosomal genes.IMPORTANCE Haemophilus influenzae colonizes the respiratory tract in humans and causes both invasive and noninvasive infections. As a threat to treatment, resistance against critically important antibiotics is on the rise in H. influenzae Identifying mechanisms for horizontal acquisition of resistance genes is important to understand how multidrug resistance develops. The present study explores the antimicrobial resistance genes and their context in beta-lactam-resistant H. influenzae with coresistance to up to four non-beta-lactam groups. The results reveal that this organism is capable of acquiring resistance to a wide range of commonly used antibiotics through conjugative transfer of mobile genetic elements and transformation of chromosomal genes, resulting in mosaic genes with a broader resistance spectrum. Strains with chromosomally mediated resistance to extended-spectrum cephalosporins, co-trimoxazole, and quinolones combined with mobile genetic elements carrying genes mediating resistance to ampicillin, tetracyclines, and chloramphenicol have been reported, and further dissemination of such strains represents a particular concern.

The impact of age on risk assessment, therapeutic practice and outcome in candidemia.

BACKGROUND: In Norway, the epidemiological situation of candidemia is followed closely. We have previously demonstrated the highest incidence of candidemia in elderly >65 years of age. However, knowledge of other aspects of this infection is lacking. OBJECTIVE: The aim of this nationwide, retrospective study was to examine risk factors, therapeutic practice and outcome in adult candidemia patients according to age. METHODS: We retrieved data from medical records from patients who developed candidemia in Norway between 1 January 2008 and 31 December 2012. Data were analyzed according to age, younger patients being between 18 and 65 years, elderly being ≥65 years of age. RESULTS: From 771 eligible patients, 738 patients (95.7%) were included (58% men, mean age 65.2 years, 58.1% being ≥65 years). Exposure to health-care related risk factors for candidemia were significantly more common in the younger patients (neutropenia, central venous catheter, mechanical ventilation and chemotherapy) who received empirical treatment more often than the elderly (29.8% vs. 21.7%, p = .01). More elderly did not received any antifungal therapy (27.3% vs 16.8%, p < 0001) and had higher mortality compared to younger patients (45.5% vs 23.9%, p < .0001). In the study population, mortality was higher with age (per 10-years increase, OR 1.43;1.28-1.59, p < 0.0001), in patients not receiving targeted therapy (OR 2.5; CI 1.82-3.36, p < .0001) or any therapy at all (OR 4.64; 3.23-6.68, p < .0001). CONCLUSIONS: Risk factors for candidemia, treatment and outcome differed significantly according to age. Given the increasing numbers of elderly, scrutiny on our clinical practice is warranted.

Distribution of emm types and subtypes among noninvasive group A, C and G streptococcal isolates in western Norway.

Characterization of the reservoir of beta-hemolytic streptococci in a community may shed light on the pathogenesis of severe infections caused by these bacteria. We used emm sequence typing to characterize group A streptococci (GAS), group C streptococci (GCS) and group G streptococci (GGS) in community isolates associated with noninvasive disease in western Norway. A total of 165 isolates during a 13-month period were examined. Skin and throat isolates accounted for 123 and 16, respectively, and the remaining 26 isolates were from other non-sterile sites. We identified 18 previously validated emm types and one novel subtype, emm11.7, among the 101 GAS isolates. The two predominant types, emm28 and 12, were found in 40.6% of the GAS isolates. Compared to other recent studies of noninvasive GAS infections from elsewhere in the world, we found a higher frequency of emm82 (5.9%) and emm87 (12.9%) and a lower frequency of emm1 (4.0%) and emm3 (4.0%). We found a different distribution of GAS emm types compared to a previous study from western Norway. Among the 64 isolates of GCS and GGS, 15 previously described emm types and four novel subtypes, stC1400.5, stCK401.3, stG6.3 and stG652.3, were found, stG6, stG643 and stG485 were the most prevalent types and accounted for 59.4% of the GCS and GGS isolates. The high proportion of skin isolates in the present study may indicate the existence of GAS, GCS and GGS strains with predominantly skin and soft tissue tropism in our community.

Aetiology and clinical features of facial cellulitis: a prospective study.

BACKGROUND: In the early 20th century, the face was the predominant site of cellulitis. Despite a relative decrease in the incidence of facial cellulitis, it is still common. There are few studies on this condition during the last decades. The aim of this study was to describe contemporary aetiological and clinical characteristics of patients admitted to hospital with non-suppurative facial cellulitis. METHODS: Patients were included prospectively. Clinical details, comorbidities and biochemistry results were recorded. Investigations included cultures of skin swab and blood and tests for streptococcal antibodies during the acute and convalescent stages. RESULTS: Sixty-five patients were included. Serology, cultures and response to penicillin monotherapy identified probable or confirmed ß-haemolytic streptococci (BHS) aetiology in 75% (49/65) of cases. Significant comorbidities were present in 54% (35/65). Fever, chills or rigors before or at admission was noted in 91% (59/65). Patients presented most often with sharply demarcated erythema and raised borders (54/64). Penicillin or penicillinase-resistant penicillin alone or in combination cured 68% (44/65) of the patients. Supplementary clindamycin was used in 28% (18/65), most often only for 1-3 days. Only four patients needed a second course of antibiotics. Clinical failure was more often seen in patients with non-BHS aetiology (p = .037). Few complications were noted; 14.5% (9/62) experienced transient diarrhoea, and only one had confirmed Clostridium difficile infection. No patients developed cerebral venous sinus thrombosis, and there were no fatalities. CONCLUSIONS: Our findings indicate that BHS are the leading cause of facial cellulitis. Most patients exhibit sharply demarcated lesions and systemic symptoms. Narrow-spectrum ß-lactam antibiotics and short hospital stay appear sufficient. Few complications and low recurrence rates were seen.

An Estimate of the Burden of Fungal Disease in Norway.

The aim of this study was to examine the burden of fungal disease in Norway, contributing to a worldwide effort to improve awareness of the needs for better diagnosis and treatment of such infections. We used national registers and actual data from the Departments of Microbiology from 2015 and estimated the incidence and/or prevalence of superficial, allergic and invasive fungal disease using published reports on specific populations at risk. One in 6 Norwegians suffered from fungal disease: Superficial skin infections (14.3%: 745,600) and recurrent vulvovaginal candidiasis in fertile women (6%: 43,123) were estimated to be the most frequent infections. Allergic fungal lung disease was estimated in 17,755 patients (341/100,000). Pneumocystis jirovecii was diagnosed in 262 patients (5/100,000), invasive candidiasis in 400 patients (7.7/100,000), invasive aspergillosis in 278 patients (5.3/100,000) and mucormycosis in 7 patients (0.1/100,000). Particular fungal infections from certain geographic areas were not observed. Overall, 1.79% of the population was estimated to be affected by serious fungal infections in Norway in 2015. Even though estimates for invasive infections are small, the gravity of such infections combined with expected demographic changes in the future emphasizes the need for better epidemiological data.

Identification of diarrheagenic Escherichia coli isolated from infants and children in Dar es Salaam, Tanzania.

BACKGROUND: Relatively few studies have been done in Tanzania to detect and classify diarrheagenic Escherichia coli (DEC) strains among children with diarrhea. This study aimed at investigating DEC among children in Dar es Salaam aged less than five years hospitalized due to acute/persistent diarrhea. METHODS: DEC were isolated from stool samples collected from two hundred and eighty children with acute/persistent diarrhea at Muhimbili National Hospital and Ilala and Mwananyamala Municipal Hospitals in Dar es Salaam. A multiplex PCR system method was used to detect a species specific gene for E.coli and ten different virulence genes for detection of five pathogroups of DEC namely enteroaggregative- (EAEC), enteropathogenic- (EPEC), enterotoxigenic- (ETEC), enteroinvasive- (EIEC) and enterohemorghagic- Escherichia coli (EHEC). RESULTS: Sixty-four patients (22.9%) harbored DEC. Forty-one of them (14.6%) were categorized as EAEC. Most of the EAEC (82.9%) were classified as typical EAEC possessing the aggR gene, and 92.6% carried the aat gene. Isolates from thirteen patients were EPEC (4.6%) and most of these (92.3%) were typical EPEC with both eae and bfpA genes. Ten isolates were identified as ETEC (3.6%) with only the heat stable toxin; either st1a or st1b but not both. Age wise, EAEC and EPEC were significantly more prevalent among the age group 0-6 months (p < 0.05). Genes for EHEC (stx1 and stx2) and EIEC (ial) were not detected in this study group. CONCLUSION: The results show a high proportion of DEC among Tanzanian children with diarrhea, with typical EAEC and typical EPEC predominating. The use of primers for both variants of ST1 (st1a and st1b) increased the sensitivity for detection of ETEC strains.