ABSTRACT
Background: Extended-spectrum β-lactamase (ESBL) producing uropathogens has become prevalent worldwide. E. coli O25b-ST131 clone, associated with blaCTX-M-15, has been reported from many parts of the world and is frequently associated with multidrug resistance. Thus far, there are no reports about this clone in Bangladesh. The objective of this study was to investigate ESBL producing uropathogens and to survey the prevalence of E. coli O25b-ST131 clone among ESBL positive E. coli isolates. Methods: From symptomatic urinary tract infection cases, a total of 800 urine samples were collected. Bacterial identification and antimicrobial susceptibility testing was performed using established methods. Screening of ESBL producers was done using the disk diffusion method. Screening positive isolates were phenotypically confirmed by double disk synergy (DDS) test. Genes encoding ESBLs (blaCTX-M-15, blaOXA-1) were identified both by PCR and DNA sequencing. Phenotypic positive ESBL producers were also studied by PCR for existence of class 1 integron. Subsequently, O25b-ST131 clone was identified by allele specific PCR. Results: Of 138 gram-negative uropathogens, 45 (32.6%) were positive for ESBLs. ESBL producers showed high frequency of antimicrobial resistance except imipenem. Among 45 ESBL producers, 36 (80%) produced blaCTX-M-15, 18 (40%) produced blaOXA-1. Fifteen (33.3%) strains simultaneously produced both blaOXA-1 and blaCTX-M-15. Class 1 integron was present in 30 (66.7%) isolates. Of the 31 blaCTX-M-15 positive E. coli, 22 (71%) were positive for E. coli O25b-ST131 clone and all (100%) belonged to B2 phylogenetic group. Conclusion: Rising antimicrobial resistance among uropathogens, and especially the emergence of blaCTX-M-15 positive E. coli O25b-ST131 clone in Bangladesh has provided urgency to the development of novel preventive and therapeutic strategies.
ABSTRACT
Diagnostic indices of Gal/Gal NAc lectin antigen and anti-lectin antibodies for amebic liver abscess were evaluated to see their usefulness. Forty [40] clinically suspected cases of liver abscess patients admitted in the Rajshahi Medical College Hospital [RMCH], Bangladesh during January to December 2007 were included. Liver abscess pus from all cases were tested for small subunit of ribosomal RNA [rRNA] gene of Entamoeba histolytica by Real Time PCR and only PCR-positive cases were further analyzed for detection of Gal/Gal NAc lectin antigen and anti-lectin antibodies in their liver abscess aspirates, plasma, saliva and urine using Enzyme-linked immunosorbent assay [ELISA] methods. Except liver abscess pus, all other samples were also tested for 20 patients suffering from diseases other than liver abscess, who served as controls for the study. Out of 40 patients, 39 were PCR-positive and considered as confirmed cases of amebic liver abscess. The rate of detection of lectin antigen and anti-lectin antibody in liver abscess pus was 12.82% and 56.41% respectively. Diagnostic sensitivities of lectin antigen in plasma, saliva and urine were 15.38% [95%CI 6-31%], 07.69% [95%CI 2-22%] and 00% respectively, while sensitivities of anti-lectin antibodies in all those samples were 100% [95%CI 88-100%], 87.17% [95%CI 72-95%] and 56.41% [95%CI 40-78%] respectively. Diagnostic specificities of lectin antigen was 100% in all specimens but for anti-lectin antibodies, specificities were 100% [95%CI 88- 100%] in plasma, 50% [95%CI 28-78%] in saliva and 70% [95%CI 46-87%] in urine. Overwhelming majority of cases [94.87%] received Metronidazole therapy for variable period before sample collection, which is correlated with low rate of antigen detection. Detection of lectin antigen for amebic liver abscess has very limited or no role where Metronidazole is used indiscriminately but detection of anti-lectin antibodies especially in plasma [100% sensitivity] and saliva [87.17% sensitivity] are excellent to satisfactory. Estimation of plasma IgG can be recommended as serodiagnostic tool for symptomatic amebic liver abscess