Systematic review of wastewater surveillance of antimicrobial resistance in human populations.

OBJECTIVES: We systematically reviewed studies using wastewater for AMR surveillance in human populations, to determine: (i) evidence of concordance between wastewater-human AMR prevalence estimates, and (ii) methodological approaches which optimised identifying such an association, and which could be recommended as standard. We used Lin's concordance correlation coefficient (CCC) to quantify concordance between AMR prevalence estimates in wastewater and human compartments (where CCC = 1 reflects perfect concordance), and logistic regression to identify study features (e.g. sampling methods) associated with high agreement studies (defined as >70% of within-study wastewater-human AMR prevalence comparisons within ±10%). RESULTS: Of 8,867 records and 441 full-text methods reviewed, 33 studies were included. AMR prevalence data was extractable from 24 studies conducting phenotypic-only (n = 7), genotypic-only (n = 1) or combined (n = 16) AMR detection. Overall concordance of wastewater-human AMR prevalence estimates was reasonably high for both phenotypic (CCC = 0.85 [95% CI 0.8-0.89]) and genotypic approaches (CCC = 0.88 (95% CI 0.84-0.9)) despite diverse study designs, bacterial species investigated and phenotypic/genotypic targets. No significant relationships between methodological approaches and high agreement studies were identified using logistic regression; however, this was limited by inconsistent reporting of study features, significant heterogeneity in approaches and limited sample size. Based on a secondary, descriptive synthesis, studies conducting composite sampling of wastewater influent, longitudinal sampling >12 months, and time-/location-matched sampling of wastewater and human compartments generally had higher agreement. CONCLUSION: Wastewater-based surveillance of AMR appears promising, with high overall concordance between wastewater and human AMR prevalence estimates in studies irrespective of heterogenous approaches. However, our review suggests future work would benefit from: time-/location-matched sampling of wastewater and human populations, composite sampling of influent, and sampling >12 months for longitudinal studies. Further research and clear and consistent reporting of study methods is required to identify optimal practice.

Tissue responses to Hydron, assessed by intraosseous implantation.

Teflon tubes containing freshly mixed, polymerized Hydron root canal filling material, fully set AH26 or Teflon were implanted into the mandible of guinea pigs and assessed histologically at 2 days, 1, 2, 4, 12 and 26 weeks. None of the materials tested elicited signs of overt or significant tissue damage, and polymerized Hydron was assessed to be as biocompatible as fully set AH26 and Teflon. Bone formed in very close apposition to the polymerized Hydron, whereas a soft tissue capsule separated the regenerated bone from implants of AH26 and Teflon.

Tissue responses to Hydron, assessed by intramuscular implantation.

Freshly mixed polymerized Hydron root canal filling material, fully set AH26 and Teflon were implanted in the quadriceps muscle of guinea pigs and assessed histologically at 2 days, 1, 2, 3, 12 and 26 weeks after implantation. All materials were characterized by peri-implant fibrous connective tissue capsule formation. Von Kossa-positive calcific material was observed at the implant-tissue interface of Hydron implants. The amount of apparently calcified material increased with time. Inflammation was not a prominent tissue response for any of the test materials, nor was a foreign body giant cell response.

Osteosarcoma of the jaws--a series from Kaduna, Nigeria.

15 primary and one metastatic osteosarcoma of the jaw bones in Nigerians are described. The age range was typical of this tumour; most cases were in the mandible. Clinical and radiographic features were often diagnostic but the microscopic appearances were varied and problematical. No metastases were detected and effective surgical treatment depended upon the degree of spread in soft tissue. Inoperable tumours had infiltrated the pharyngeal and tonsillar area. Some resected cases survived for one year or more.

Chemoprophylaxis with oral amoxycillin against bacterial endocarditis: when should second doses be administered after dentistry?

The adequacy of serum bactericidal activity after oral amoxycillin given as prophylaxis against infective endocarditis was studied using a double blind randomised protocol in healthy volunteers having dentistry. One hour before their procedure 38 patients received 3 g amoxycillin syrup and 12 received matching placebo. Venous blood samples were drawn before and one and nine hours after dosing and serum amoxycillin concentrations determined using a standard bioassay. Samples containing amoxycillin had inhibitory titres measured against two reference isolates of viridans streptococci known to have caused infective endocarditis. The susceptibility to amoxycillin of one strain was high and the other low, respective minimal bactericidal and inhibitory concentrations being 0.08 and 0.04 mumol/l (0.03 and 0.015 microgram/ml) and 2.74 and 1.37 mumol/l (1 and 0.5 microgram/ml). Amoxycillin was detected in only post-treatment samples of patients given the active drug. There were no significant correlations between one or nine hour drug concentrations and age or physical characteristics, nor was there any relation to preceding food consumption. Correlations between drug concentrations at one and nine hours were weak (r = 0.34; p less than 0.05), but between corresponding drug concentrations and serum inhibitory titres there were consistent correlations (r = 0.46-0.48; p less than 0.005). Against the low susceptibility reference isolate bactericidal amoxycillin concentrations were encountered in only 20 of the 38 nine hour samples (95% confidence limits 34% and 66%). When repeat doses of amoxycillin are indicated after dentistry they should be given about four hours later, not eight hours later as commonly practised.

Dentistry in Hong Kong: a look into the past and a glimpse of the future.

To meet the needs of a population numbering 5.3 million Hong Kong has, until now, relied upon training of their dentists in other countries. A net decline in manpower, predicted 10 years ago, has now become an increase of 85 per cent. Early in 1985, the first graduates will emerge from the new dental school and will make further manpower available. The water in Hong Kong has been fluoridated since 1961. Since then there has been a substantial reduction in dental caries but the treatment need still remains very high. A recent pilot study has shown that both the prevalence and severity of destructive periodontal disease are causes for considerable concern.

Topical carcinogenesis by N-methyl-N-nitrosourea in Syrian hamster cheek-pouch and oral mucosa.

Pouches of weanlings were painted 3 times a week for 4 weeks with 0.5 per cent NMU in acetone, using a technique designed to localize oncogenesis. Ventral lingual mucosa was painted at the same time. Premalignant, dysplastic lesions or carcinomas arose in pouches of 88 per cent of animals that survived from 8 to 54 weeks, but the majority of these lesions were not localized to the painted area. Biliary hyperplasia, papillomas of the forestomach and abnormalities of the incisor teeth were found in a small number of animals. These changes suggested that systemic absorption of NMU had occurred. No lesions were induced beneath the tongue but occasional premalignant and malignant changes were found in other parts of the mouth.

Intermaxillary fixation: how practicable is emergency jaw release?

Intermaxillary fixation as part of management of facial fractures or following osteotomy for facial deformity presents unique problems to the anaesthetist. It is traditional practice to keep wire cutters available by the patient at all times to enable quick release of the jaws in emergency. The efficiency of release was tested by timing various members of the management team. The time taken to release the jaws was an average 35.3 seconds by experienced oral surgeons and an average 2 minutes 9 seconds by hospital staff involved in caring for these patients and was not a practical proposition for a lay person. Thus the value of releasing fixation is questionable in the initial care of obstruction or vomiting. Techniques of avoiding and managing these problems are discussed.