Non-lactose fermenting Escherichia coli: Following in the footsteps of lactose fermenting E. coli high-risk clones.

Multi-resistant pathogenic strains of non-lactose fermenting Escherichia coli (NLF E. coli) are responsible for various intestinal and extraintestinal infections. Although several studies have characterised such strains using conventional methods, they have not been comprehensively studied at the genomic level. To address this gap, we used whole-genome sequencing (WGS) coupled with detailed microbiological and biochemical testing to investigate 17 NLF E. coli from a diagnostic centre (icddr,b) in Dhaka, Bangladesh. The prevalence of NLF E. coli was 10%, of which 47% (8/17) exhibited multi-drug resistant (MDR) phenotypes. All isolates (17/17) were confirmed as E. coli and could not ferment lactose sugar. WGS data analysis revealed international high-risk clonal lineages. The most prevalent sequence types (STs) were ST131 (23%), ST1193 (18%), ST12 (18%), ST501 (12%), ST167 (6%), ST73 (6%) and ST12 (6%). Phylogenetic analysis corroborated a striking clonal population amongst the studied NLF E. coli isolates. The predominant phylogroup detected was B2 (65%). The bla CTX-M-15 extended-spectrum beta-lactamase gene was present in 53% of isolates (9/17), whilst 64.7% (11/17) isolates were affiliated with pathogenic pathotypes. All extraintestinal pathogenic E. coli pathotypes demonstrated ß-hemolysis. Our study underscores the presence of critical pathogens and MDR clones amongst non-lactose fermenting E. coli. We suggest that non-lactose fermenting E. coli be considered equally capable as lactose fermenting forms in causing intestinal and extraintestinal infections. Further, there is a need to undertake systematic, unbiased monitoring of predominant lineages amongst non-lactose fermenting E. coli that would help in better treatment and prevention strategies.

A comparison of traditional diarrhoea measurement methods with microbiological and biochemical indicators: A cross-sectional observational study in the Cox's Bazar displaced persons camp.

BACKGROUND: Water, Sanitation, and Hygiene (WASH) systems aim to reduce the spread of enteric pathogens, particularly amongst children under five years old. The most common primary outcome of WASH trials is carer-reported diarrhoea. We evaluate different diarrhoea survey instruments as proxy markers of enteric pathogen presence in stool. METHODS: We recruited 800 community-based participants from the Cox's Bazar Displaced Person's Camp in Bangladesh, split evenly between the rainy (July/August 2020) and dry (November/December 2020) periods. Participants were randomized evenly into either a standard survey asking carers if their child under five years old has had diarrhoea in the past fortnight, or a pictorial survey asking carers to pick from a pictorial chart which stools their child under five years old has had in the past fortnight. We collected stools from a random sub-sample of 120. Stools were examined visually, and tested for proteins associated with enteric infection and 16 enteric pathogens. We calculated sensitivities and specificities for each survey type, visual examination, and proteins with respect to enteric pathogen presence. FINDINGS: The sensitivity of the standard survey for enteric pathogen presence was 0.49[95%CI:0.32,0.66] and the specificity was 0.65[0.41,0.85]. Similar sensitivities and specificities were observed for pictorial survey, visual inspection, and proteins. INTERPRETATION: While diarrhoea is an important sign in clinical practice it appears that it is a poor proxy for enteric pathogen presence in stool in epidemiological surveys. When enteric infection is of interest, this should be measured directly. FUNDING: The project was funded by the National Institutes for Health Research Global Health Research Unit on Improving Health in Slums (16/136/87) and by the University of Warwick.

High prevalence of plasmid-mediated quinolone resistance (PMQR) among E. coli from aquatic environments in Bangladesh.

Fluro(quinolones) is an important class of antibiotic used widely in both human and veterinary medicine. Resistance to fluro(quinolones) can be acquired by either chromosomal point mutations or plasmid-mediated quinolone resistance (PMQR). There is a lack of studies on the prevalence of PMQR in organisms from environmental sources in Bangladesh. In this study, we investigated the occurrence of PMQR genes in E. coli from various water sources and analysed associations between multi-drug resistance (MDR) and resistance to extended spectrum ß-lactam antibiotics. We analysed 300 E. coli isolates from wastewaters of urban live-bird markets (n = 74) and rural households (n = 80), rural ponds (n = 71) and river water samples (n = 75) during 2017-2018. We isolated E. coli by filtering 100 ml of water samples through a 0.2µm cellulose membrane and incubating on mTEC agar media followed by identification of isolated colonies using biochemical tests. We selected one isolate per sample for detection of PMQR genes by multiplex PCR and tested for antibiotic susceptibility by disc diffusion. Clonal relatedness of PMQR-positive isolates was evaluated by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). About 66% (n = 199) of E. coli isolates harbored PMQR-genes, predominantly qnrS (82%, n = 164) followed by aac(6')-lb-cr (9%, n = 17), oqxAB (7%, n = 13), qnrB (6%, n = 11) and qepA (4%, n = 8). Around 68% (n = 135) of PMQR-positive isolates were MDR and 92% (n = 183) were extended spectrum ß-lactamase (ESBL)-producing of which the proportion of positive samples was 87% (n = 159) for blaCTX-M-1' 34% (n = 62) for blaTEM, 9% (n = 16) for blaOXA-1, blaOXA-47 and blaCMY-2, and 2% (n = 4) for blaSHV. Further, 16% (n = 32) of PMQR-positive isolates were resistant to carbapenems of which 20 isolates carried blaNDM-1. Class 1 integron (int1) was found in 36% (n = 72) of PMQR-positive E. coli isolates. PMQR genes were significantly associated with ESBL phenotypes (p≤0.001). The presence of several PMQR genes were positively associated with ESBL and carbapenemase encoding genes such as qnrS with blaCTXM-1 (p<0.001), qnrB with blaTEM (p<0.001) and blaOXA-1 (p = 0.005), oqxAB and aac(6')-lb-cr with blaSHV and blaOXA-1 (p<0.001), qnrB with blaNDM-1 (p<0.001), aac(6')-lb-cr with blaOXA-47 (p<0.001) and blaNDM-1 (p = 0.002). Further, int1 was found to correlate with qnrB (p<0.001) and qepA (p = 0.011). ERIC-PCR profiles allowed identification of 84 of 199 isolates with 85% matching profiles which were further grouped into 33 clusters. Only 5 clusters had isolates (n = 11) with identical ERIC-PCR profiles suggesting that PMQR-positive E. coli isolates are genetically heterogeneous. Overall, PMQR-positive MDR E. coli were widely distributed in aquatic environments of Bangladesh indicating poor wastewater treatment and highlighting the risk of transmission to humans and animals.

Clinical and functional staging of oral submucous fibrosis.

OBJECTIVE: To investigate the association of location of bands in oral submucous fibrosis and extent of mouth-opening. DESIGN: Cross-sectional study. SETTING: University hospital, Pakistan. SUBJECTS: 325 patients who presented with oral submucous fibrosis in Karachi between January 1992 and October 1994, of whom 288 had data sufficient for analysis. MAIN MEASURES: Location of fibrous bands in the mouth and interincisal distance (mm). RESULTS: All subjects with labial bands had bands in the fauces, and all but one who had labial bands also had buccal bands. All those with buccal bands also had bands in the fauces. Of those with buccal bands, 42% did not have labial bands. The proportion of patients with bands in all three sites increased from functional stage A (interincisal opening < or = 10 mm) to stage C (interincisal opening > or = 20 mm) with a simultaneous reduction in the proportion of people with bands in one or two sites (X2 = 105, df = 4, P < 0.0001). CONCLUSIONS: Bands are common at the back of the mouth in mild cases of oral submucous fibrosis and, as the disease increases in severity, are more likely to be found anteriorly as well.

Paan without tobacco: an independent risk factor for oral cancer.

Oral cancer is the second most common cancer in women and the third most common in men in Pakistan. Tobacco is smoked and chewed extensively in Pakistan. Paan is a quid of piper betel leaf that contains areca nut, lime, condiment, sweeteners, and sometimes tobacco, which is also used extensively. We did this study to clarify the independent association of paan and oral cancer. Between July 1996 and March 1998, we recruited biopsy-proven, primary cases of oral squamous-cell carcinoma, from 3 tertiary teaching centers in Karachi, Pakistan, and controls pair-matched for age, gender, hospital and time of occurrence, excluding persons with a past or present history of any malignancy. There were 79 cases and 149 controls. Approximately 68% of the cases were men, 49 years old on average, the youngest being 22 years old and the eldest 80. People with oral submucous fibrosis were 19.1 times more likely to develop oral cancer than those without it, after adjusting for other risk factors. People using paan without tobacco were 9.9 times, those using paan with tobacco 8.4 times, more likely to develop oral cancer as compared with non-users, after adjustment for other covariates. This study identifies an independent effect of paan without tobacco in the causation of oral cancer. Its findings may be of significance in South Asian communities where paan is used, and among health-care providers who treat persons from South Asia.

Combined effects of argon laser irradiation and fluoride treatments in prevention of caries-like lesion formation in enamel: an in vitro study.

The sample of this study consisted of 10 human permanent molars, which were sectioned into tooth quarters using slow speed diamond saw (Isomet), then a quarter from each tooth was assigned to one of four treatment groups: A) control (no treatment); B) argon laser only; C) argon laser plus neutral sodium fluoride for 4 minutes; D) argon laser with zinc fluoride for 4 minutes; each tooth quarter was coated with acid resistant varnish, leaving a window of 2 mm x 3 mm of sound enamel exposed. The results were that teeth treated with argon laser and then with zinc fluoride for four minutes have significantly reduced white spotting or etching. Zinc fluoride and argon laser combination are particularly effective in compensating for carbonate inclusion. It has a property of stabilizing hydroxyapetite crystal and restoring the structural defects of this crystal. Caries detection dye is a reliable diagnostic tool for white spot lesions. It reduces the false positive and false negative results by 60%, when compared with visual 16x magnification.

Increased severity of oral submucous fibrosis in young Pakistani men.

OBJECTIVE: To investigate the influence of age and sex on the incidence of severe oral submucous fibrosis (mouth opening 15 mm or less). DESIGN: Case (severe disease) control (mild disease) study. SETTING: University hospital, Pakistan. SUBJECTS: 147 patients with severe (mouth opening 15 mm or less) and 83 with mild disease (mouth opening 20 mm or more). MAIN MEASURES: Influence of sex and age on severity of oral submucous fibrosis. RESULTS: Men were twice as likely as women to have severe disease (odds ratio (OR) 2.0, 95% confidence interval (CI) of OR 1.15 to 3.47, P=0.02). Men in the 20-39 year age group were 4.8 times as likely as women to have severe disease (OR 5.8, 95% CI 2.15 to 15.5, P=0.00004). Men aged 40 years or more were 40% less likely to have severe disease than women (OR 0.6, 95% CI 0.19 to 1.88, P=0.39). CONCLUSIONS: Smoking increases the carcinogenic potential of submucous fibrosis. As men in this population smoke more than women, men with severe oral submucous fibrosis may develop oral cancer and die younger. Alternatively, young men may consume more areca nut than women.

Surgical treatment of mandibular retrusion by a post-condylar cartilage graft.

Mandibular advance in 22 retrognathic adolescent patients (median age 15.7 months) was carried out using a post-condylar graft of lyophilised cartilage. The post-surgical changes were evaluated by a computer-aided digitisation programme after a mean follow-up period of 23 months. Horizontal relapse of the anterior mandible was 3.45% overall, with a corresponding increase of 6.13% in the vertical height of the anterior face. Significant individual relapse in four of the cases resulted from condylar remodelling. Changes at the angle of the mandible and rotational changes of the mandibular plane were also measured.