Incidence of SHV-1 and CTX-M-15 Extended Spectrum of ß-Lactamases Producing Gram-Negative Bacterial Isolates from Antenatal Women with Asymptomatic Bacteriuria DC01-DC04
Dr. Ramakrishnan Kalaivani,
Associate Professor, Department of Microbiology, Mahatma Gandhi Medical College and Research Institute,
Sri BalajiVidyapeeth, (Deemed to be University), Pillaiyarkuppam, Pondicherry, India.
Introduction: Asymptomatic Bacteriuria (ASB) occurs in 2% to 10% of cases during pregnancy, the risk of onset increases between 9th to 17th weeks of gestation. ASB leads to adverse anomalies like acute pyelonephritis, low birth weight infants and premature delivery. The incidence of Extended Spectrum ß-lactamases (ESBLs) e.g., blaCTX-M, blaSHV and blaTEM type producing uropathogenic bacteria have been increasing over the years which has lead to additional therapeutic burden to the patients.
Aim: To investigate the ESBL producing Multidrug Resistant (MDR) Gram negative bacteria and to ascertain the most prevalent ESBL gene among the antenatal women with asymptomatic bacteriuria.
Materials and Methods: A prospective cohort study involving 637 antenatal mother with asymptomatic bacteriuria was conducted.Their mid-stream clean catch urine sample were collected and processed. Gram-negative pathogens were isolated and phenotypically confirmed for ESBL production. All the ESBL positive isolates were further screened by conventional Polymerse Chain Reaction (PCR) for the presence of blaCTX-M, blaSHV and blaTEM using gene specific primers and sequenced.
Results: From a total of 637 samples, 271 gram-negative pathogens were isolated. Phenotypically 37% (101) were ESBL producers. Out of these 101 isolates, 73%(74) were MDR isolates and none of them carried blaTEM. The presence of blaCTX-M and blaSHV were noted in 58% (59) and 4%(4) of isolates respectively. Sequence analysis confirmed them to be belonging to the same variant i.e., blaCTXM-15 and blaSHV-1.
Conclusion: Occurrence of blaCTX M-15 and blaSHV-1 genes among the isolates reflects their prevalence within the community. Inappropriate, indiscriminate, inadequate antibiotics could be the source for wide dissemination of ß-lactamases. Proper, adequate antenatal checkup with periodic urine examination will reduce the morbidity and mortality among antenatal mothers due to asymptomatic bacteriuria.