Comparison of Horizontal blaCTX-M Gene Transfer via Conjugation among Extended Spectrum ß-Lactamases Producing Escherichia coli Isolates from Patients with Urinary Tract Infection, Their Animals, and Environment.

Background: The dissemination of the extended spectrum ß-lactamases (ESBL) producing E. coli poses a significant public health problem. Understanding the efficiency and frequency of horizontal gene transfer via conjugation of ESBL producing E. coli is imperative towards devising prevention and control measures. This study compared the frequencies and efficiencies of horizontal blaCTX-M gene transfer via conjugation among Escherichia coli isolates from urine and gastrointestinal tract (GIT) of patients with urinary tract infection (UTI), their animals and environment. Methods: Horizontal blaCTX-M gene transfer via conjugation by a broth mating experiment was performed using 50 confirmed ESBL producing E. coli isolates as donors and Escherichia coli J53 (F-, met, pro, Azr), as the recipient. The transconjugants were detected and their frequencies and efficiencies of conjugation were measured and compared between ESBL producing E. coli isolates multi-sourced from urine, GIT, animals and environment. Antimicrobial susceptibility testing of all resulting transconjugants was performed. DNA was extracted from all transconjugants to confirm the presence and the acquisition of blaCTX-M gene. Results: Out of 50 ESBL producing E. coli isolates harboring blaCTX-M gene, 37 (74.0%) successfully exercised horizontal gene transfer through conjugation. All transconjugants were confirmed phenotypically and genotypically by PCR. Of note, all of the isolates from environment 100.0% (7/7) performed conjugation, exhibiting the highest transfer efficiency, followed by isolates from urine and animals, with the conjugation transfer efficiency of 77.8% (14/18) and 76.1% (10/13), respectively. The isolates from the environment conjugated with a significant more efficiency than those from the GIT [Two-sample test of proportions; p-value = 0.0119]. The overall conjugation transfer frequencies ranged from 0.4 × 10-14 - 5.5 × 10-11 per donor cells with the highest median conjugation transfer frequency observed among isolates from animal (3.23 × 10-12 [IQR: 0.70 × 10-12 - 7.22 × 10-12]) followed by that of isolates from the environment (1.60 × 10-12 [IQR: 0.30 × 10-12 - 5.0 × 10-12]). Conclusion: ESBL producing E. coli from human, animals and environment exercises horizontal blaCTX-M gene transfer efficiently with the highest occurrence among isolates from the environment and animals. The antimicrobial resistance control and prevention strategies should be widened up to explore strategies to prevent horizontal AMR gene transfer.

Characterisation of genes encoding for extended spectrum ß-lactamase in Gram-negative bacteria causing healthcare-associated infections in Mwanza, Tanzania.

Healthcare-associated infections (HCAIs) caused by extended spectrum ß-lactamase-producing Gram-negative bacteria (ESBL-GNB) increase morbidity and mortality. This cross-sectional study characterised ESBL genes (bla CTX-M, bla TEM and bla SHV) among 30 ceftriaxone-resistant GNB causing HCAIs between January 2022 and July 2022 by multiplex polymerase chain reaction assay at the zonal referral hospital in Mwanza, Tanzania. Twenty-five (83.3%) had at least one ESBL gene, of which 23/25 (92.0%) carried the bla CTX-M gene. Seventy-two percent (18/25) of the GNB-ESBL isolates carried more than one ESBL gene, of which the majority (88.8%; n = 16/25) carried the bla CTX-M and bla TEM genes. Extended spectrum ß-lactamase genes, particularly bla CTX-M, are common among ceftriaxone-resistant GNB causing HCAIs. What this study adds: This study revealed the distribution of genes (bla CTX-M, bla TEM and bla SHV) coding for ESBL production among ceftriaxone resistant GNB causing HCAIs However, all ESBL producing GNB were susceptible towards ceftriaxone-sulbactam indicating that ceftriaxone-sulbactam may be empirically prescribed for treating patients with HCAIs.

Bacterial Contamination of Medical Doctors and Students White Coats at Kilimanjaro Christian Medical Centre, Moshi, Tanzania.

Background. Microbial transmission from patient to patient has been linked to transient colonization of health care workers attires. Contamination of health care workers' clothing including white coats may play a big role in transmission of microbes. Study Objective. This study was conducted to determine the type of bacterial contamination on the white coats of medical doctors and students and associated factors. Methods. A cross-sectional study with purposive sampling of the bacterial contamination of white coats was undertaken. Demographic variables and white coats usage details were captured: when the coat was last washed, frequency of washing, washing agents used, and storage of the white coats. Swabs were collected from the mouth of left and right lower pockets, sleeves, and lapels of white coat in sterile techniques. Results. Out of 180 participants involved in the current study, 65.6% were males. Most of the coats were contaminated by staphylococci species and other bacteria such as Gram negative rods. Conclusion and Recommendations. White coats are potential source of cross infection which harbour bacterial agents and may play a big role in the transmission of nosocomial infection in health care settings. Effort should be made to discourage usage of white coats outside clinical areas.