Biofilm-producing and specific antibiotic resistance genes in Pseudomonas aeruginosa isolated from patients admitted to a tertiary care hospital, Bangladesh.

Objectives: Biofilms are responsible for persistent infections and antimicrobial resistance. Pseudomonas aeruginosa was investigated with its ability to form biofilm by detecting genes responsible for producing biofilms and biofilm-specific antimicrobial resistance. The association between antibiotic resistance and biofilm was investigated. Methods: This cross-sectional study was conducted from July 2017 to December 2018. A total of 446 samples (infected burn, surgical wounds, and endotracheal aspirate) were collected from admitted patients of Dhaka Medical College and Hospital, Bangladesh. P. aeruginosa was isolated and identified by biochemical tests and polymerase chain reaction. Biofilm production by tissue culture plate method followed by detection of biofilm-producing genes (pqsA, pslA, pslD, pslH, pelA, lasR) and biofilm-specific antibiotic resistance genes (ndvB, PA1874, PA1876, PA1877) by polymerase chain reaction were done. Antibiotic susceptibility test was carried out by disk diffusion method; for colistin agar dilution method of minimal inhibitory concentration was followed. Results: Among 232 (52.02%) positive strains of P. aeruginosa, 24 (10.30%) produced biofilms in tissue culture plate. Among biofilm-producing genes, pqsA was the highest (79.17%). pslA and pelA were 70.83%, pslD 45.83%, pslH and lasR 37.5%. Among biofilm-specific antibiotic resistance genes, 16.67% were ndvB, and 8.33% were PA1874 and PA1877. Biofilm-forming strains were significantly resistant to colistin. Conclusions: Detection of biofilm-forming genes may be a good tool for the evaluation of biofilm production, which will help in prompt and better management of chronic or device-associated infections.

Distribution of Virulence Genes among Enterococcus species Isolated from Patients of Urinary Tract Infection Attended in a Tertiary Care Hospital of Bangladesh.

Enterococcus species was frequently considered to be commensal organisms but last few decades it has emerged as an important cause of health care associated infections. The presence of virulent genes is one of a key factor for which Enterococcus spp. is gaining attention. In this study, we aim to determine the frequency of virulence genes in uropathogenic Enterococcus species. A total of 46 Enterococcus strains isolated from January 2017 to December 2017. Urine samples were collected from adult clinically suspected urinary tract infected patients from the inpatient and outpatient department of Dhaka Medical College Hospital, Bangladesh irrespective of sex and antibiotic intake. Potential virulence genes such as asa, esp, ace, ebp, cyl, gelE, pilA, pilB, sprE, scm, fms8, ecbA and hyl were detected by PCR using specific primers. Among 46 culture positive Enterococcus, 33(71.74%) were E. faecalis, 11(23.91%) were E. faecium, 2(4.35%) were unidentified. Of the 44 identified Enterococci (33 E. faecalis and 11 E. faecium), 43(97.73%) were positive for pilB, 41(93.18%) for both scm and fms8, 39(88.64%) were positive for ebp, 34(77.27%) for gelE, 32(72.78%) for esp, 31(70.45%) for ecbA, 30(68.18%) for sprE, 28(63.67%) for pilA, 25(56.82%) for ace, 21(47.73%) for cyl, 20(45.45%) for asa and 3(6.82%) for hyl gene. Different virulence factors could be associated with the pathogenicity of E. faecalis and E. faecium and these genes are extensively available among the Enterococcus species.

Detection of Quinolone resistance Qnr genes and its association with Extended Spectrum ß-lactamase and AmpC ß-lactamase genes in Qnr Positive Enterobacteriaceae in Bangladesh.

This cross-sectional study was conducted to explore quinolone resistant Enterobacteriaceae followed by searching the prevalence of three groups of quinolone resistance genes (QnrA, QnrB and QnrS) from January 2015 to December 2015 at Dhaka Medical College hospital, Bangladesh. Then genes for ESBL and AmpC ß-lactamase were detected among Qnr positive strains for better understanding the role of these genes for multiple drug resistance. Total 340 urines, sputum, wound swab and blood samples were collected from DMCH. Total 270(79.41%) Enterobacteriaceae were isolated from 340 samples. Out of 270 Enterobacteriaceae, 225(83.33%) were quinolone (ciprofloxacin) resistant strains. Qnr genes were detected in 141(62.67%) of the 225 quinolone resistant Enterobacteriaceae. Total 187 Qnr genes [84(59.57%) QnrS, 70(49.64%) QnrB and 33(23.40%) QnrA] were detected from 141 quinolone resistant strains. Total 48(34.04%) ESBL producers were detected by DDS test and 47(33.33%) ESBL producers were positive by PCR among 141 Qnr positive strains. QnrA was co-existed with CTX-M-15. QnrB was co-existed with TEM, CTXM-15 and OXA-1. QnrS genes were also associated with TEM, CTX-M-15 and OXA-1. Among 52 cefoxitin resistant Qnr positive strains, 22(42.31%) AmpC ß-lactamase producers were detected by Modified three-dimensional test (MTDT) and 45(86.54%) AmpC ß-lactamase producers were detected by PCR. QnrA had been identified with DHA, ACC, EBC and CIT while QnrB had been identified with DHA, ACC, EBC and CIT. QnrS had also been co-existed with DHA, ACC, EBC and CIT. The results of this study provided insights into the high proportion of Qnr genes among isolated Enterobacteriaceae. Simultaneous presence of Qnr genes and genes for extended-spectrum ß-lactamase or AmpC ß-lactamase were observed in multidrug resistant Enterobacteriaceae.

Postoperative wound infection by nontuberculous mycobacteria; case series in Dhaka Medical College Hospital of Bangladesh.

The incidence of nontuberculous mycobacterial (NTM) infections after operations is increasing in Bangladesh but data regarding clinical presentation, diagnosis, treatment, and prognosis after treatment are lacking. In this case series, three patients having persistent serous discharge from incision wound after operation were studied. Discharge from wounds were collected, wet film microscopy was performed for pus cells and fungus, Gram stain, Ziehl-Neelsen (ZN) stain, culture in routine culture media and Lowenstein-Jensen (LJ) media, Xene-Xpert for mycobacterium tuberculosis (MTB), polymerase chain reaction (PCR) for NTM were done. NTM-positive patients were treated initially for 6 weeks with four drugs regimen (clarithromycin 500 mg 12 hourly, ciprofloxacin 500 mg 12 hourly, linezolid 400 mg 12 hourly, and amikacin 500 mg 12 hourly), followed by 5 months with three drugs regimen (clarithromycin 500 mg 12 hourly, ciprofloxacin 500 mg 12 hourly, and linezolid 400 mg 12 hourly) as a maintenance dose. Cessation of discharge occurred within 3-4 weeks after starting treatment, and the wounds were healed.

Carbapenem Resistance among Klebsiella pneumoniae in a Tertiary Care Hospital in Bangladesh.

Carbapenem-resistant K pneumoniae (CRKP) clinical isolates have spread widely now-a-days throughout the world. This study was designed to investigate the carbapenem resistance among Klebsiella pneumoniae and to see anitimicrobial susceptibility of these CRKP isolates to other antimicrobials in a tertiary care hospital in Bangladesh. K pneumoniae was detected by standard methods and various biochemical tests like Triple Sugar Iron (TSI) agar media, Simmons citrate agar media and Motility-Indole-Urea (MIU) agar media. Imipenem resistance was used as the indicator for carbapenem resistance. Agar dilution method was used to determine MIC of imipenem. CRKP were tested for their antimicrobial susceptibility by Kirby-Bauer modified disc-diffusion technique as per Clinical and Laboratory Standard Institute (CLSI) guidelines and United States Food and Drug Administration (FDA) guidelines. Total 75 K pneumoniae were isolated. Among the isolated K pneumoniae, 28(37.33%) were resistant to carbapenem. Most of the CRKP were recovered from intensive care unit. MIC of CRKP ranged from ≥32µg/ml to ≤4µg/ml. Most of the CRKP were resistant to other antimicrobials. Carbapenem resistance in K pneumoniae is increasing in Bangladesh, which is very alarming and we should give importance on standard guideline of antimicrobials use.

Measuring the Effectiveness of COVID-19 Vaccines Used during a Surge of the Delta Variant of SARS-CoV-2 in Bangladesh: A Test-Negative Design Evaluation.

BACKGROUND: From May to December 2021, Bangladesh experienced a major surge in the Delta variant of SARS-CoV-2. The earlier rollout of several vaccines offered the opportunity to evaluate vaccine effectiveness against this variant. METHODS: A prospective, test-negative case-control study was conducted in five large hospitals in Dhaka between September and December 2021. The subjects were patients of at least 18 years of age who presented themselves for care, suffering COVID-like symptoms of less than 10 days' duration. The cases had PCR-confirmed infections with SARS-CoV-2, and up to 4 PCR test-negative controls were matched to each case, according to hospital, date of presentation, and age. Vaccine protection was assessed as being the association between the receipt of a complete course of vaccine and the occurrence of SARS-CoV-2 disease, with symptoms beginning at least 14 days after the final vaccine dose. RESULTS: In total, 313 cases were matched to 1196 controls. The genotyping of case isolates revealed 99.6% to be the Delta variant. Receipt of any vaccine was associated with 12% (95% CI: -21 to 37, p = 0.423) protection against all episodes of SARS-CoV-2. Among the three vaccines for which protection was evaluable (Moderna (mRNA-1273); Sinopharm (Vero Cell-Inactivated); Serum Institute of India (ChAdOx1 nCoV-19)), only the Moderna vaccine was associated with significant protection (64%; 95% CI: 10 to 86, p = 0.029). Protection by the receipt of any vaccine against severe disease was 85% (95% CI: 27 to 97, p = 0.019), with protection estimates of 75% to 100% for the three vaccines. CONCLUSIONS: Vaccine protection against COVID-19 disease of any severity caused by the Delta variant was modest in magnitude and significant for only one of the three evaluable vaccines. In contrast, protection against severe disease was high in magnitude and consistent for all three vaccines. Because our findings are not in complete accord with evaluations of the same vaccines in more affluent settings, our study underscores the need for country-level COVID-19 vaccine evaluations in developing countries.

Prevalence of Colistin Resistance in Klebsiella pneumoniae Isolated from a Tertiary Care Hospital in Bangladesh and Molecular Characterization of Colistin Resistance Genes among Them by Polymerase Chain Reaction and Sequencing.

Resistance to colistin, the last resort of treatment for multidrug resistant organisms has increased now-a-days. This cross-sectional study was conducted in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh, from July 2016 to June 2017 and was designed to investigate the colistin resistance profile along with the genetic background of colistin resistance among Klebsiella pneumoniae in a tertiary care hospital in Bangladesh. K. pneumoniae was detected by colony morphology on culture media and various biochemical tests. Agar dilution method was used to determine MIC of colistin. PCR was done for detection of colistin resistance genes and sequencing of the amplified mgr B gene products was done. Total 75(23.73%) K. pneumoniae were isolated. Among the isolated K. pneumoniae, 8(10.67%) were resistant to colistin. MIC of colistin of resistant isolates ranged from ≥64µg/ml to ≤4µg/ml. Out of 8 colistin resistant K. pneumoniae, 4(50.00%) were positive for mgr B gene and 3(37.50%) were positive for pho Q gene. Colistin resistance in K. pneumoniae is increasing in Bangladesh, which is very alarming and we should give importance on standard guideline of antimicrobials use.

Association of Virulence with Antimicrobial Resistance among Klebsiella pneumoniae Isolated from Hospital Settings in Bangladesh.

Introduction: Infections caused by multidrug-resistant (MDR) hypervirulent Klebsiella pneumoniae are difficult to treat and associated with high mortality rates. Hence, this study was conducted to determine the antibiotic resistance pattern along with the distribution of virulence genes among isolated string test positive and negative strains. Materials and Methods: A total of 44 K. pneumoniae strains were isolated following standard microbiological methods from 350 different clinical samples from patients admitted to Dhaka Medical College Hospital, Bangladesh. String test was done to detect the hypermucoid phenotype. Antimicrobial resistance (AMR) pattern was determined by dichlorodiphenyltrichloroethane (except colistin and fosfomycin) among all isolates. Polymerase chain reaction was done to detect the hypervirulence genes (magA, rmpA, rmpA2 iutA, iroN). Results: In this study, 21/44 (47.73%) of the isolated K. pneumoniae were string test positive and distribution of the virulence genes except rmpA2 was higher among them. A total of 15/44 (34.09%) of the isolated K. pneumoniae were MDR, 10/44 (22.73%) were extensively drug resistant, 1/44 (2.27%) was pan drug resistant, and 14/44 (31.82%) were colistin resistant. Isolated organisms were highly resistant to third-generation cephalosporins and most sensitive to fosfomycin in this study. Although all the string test positive strains showed higher resistance rates than the string test negative ones toward most of the tested antibiotics, only the differences of resistance rates to amoxiclav and tigecycline among the two phenotypes were statistically significant. Conclusion: Our findings highlight the importance of surveillance of the AMR pattern of hypervirulent K. pneumoniae in clinical samples. Therefore, a response to check the global dissemination of this hypervirulent K. pneumoniae with resistance determinants is urgently needed.

Identification of Genes Encoding Aminoglycoside Modifying Enzymes among Clinical Isolates of Proteus species at a Tertiary Care Hospital in Dhaka, Bangladesh.

Proteus is considered as one of the major opportunistic pathogens liable for nosocomial infections and acquired several resistances to a wide range of antimicrobials such as aminoglycosides. The most common mechanism of aminoglycoside resistance is the inactivation of drugs by modifying enzymes. So, this cross-sectional study was undertaken to investigate the occurrence of aminoglycoside resistance and identify aminoglycoside modifying enzyme (AME) genes among clinical isolates of aminoglycoside resistant Proteus spp. A total of 40 Proteusmirabilis and Proteus vulgaris were isolated in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from July 2018 to June 2019 of 500 wound swab & pus, urine and blood samples. Disk diffusion test was performed by modified Kirby Bauer method. Minimum inhibitory concentration (MIC) of amikacin was determined by agar dilution method. PCR was used to detect aac(3)-Ia, aac(6')-Ib, ant(4')-IIa, ant(2'')-Ia a and aph(3'')-Ib AMEs genes among aminoglycoside resistant Proteus spp. Sequencing of aac(6')-Ib gene was performed to identify aac(6')-Ib-cr variant. Thirty-two (80%) aminoglycoside resistant isolates were detected during disk-diffusion technique. The marked increase in MIC was observed between 256 - ≥2048µg/ml to amikacin. The most prevalent AME-genes were aac(6')-Ib (37.5%), ant(2'')-Iaa (21.86) followed by ant(4')-IIa(12.5%), aph(3'')-Ib (12.5%) andaac(3)-Ia (9.38%). The most frequent combination was aac(6')-Ib + aac(3)-Ia+ant(2'')-Iaa and aac(6')-Ib + ant(4')-IIa + aph(3'')-Ib(2 strains) followed by aac(6')-Ib + aac(3)-Ia(1 strain). Sequencing of aac(6')-Ib gene in this study did not harbor aac(6')-Ib-cr variant gene. The results of this study provide insight into the presence of high AME-genes among Proteus spp. in Bangladesh.

Prevalence of qnr and aac(6')-Ib-cr Genes in Clinical Isolates of Proteus spp. at a Tertiary Care Hospital in Dhaka, Bangladesh.

Plasmid mediated quinolone resistance (PMQR) has been revealed to play not only a significant role in quinolone resistance but also this drug resistance can spread from one bacterium to another. There is limited data regarding the prevalence of PMQR are available from Bangladesh. So, the aim of this study was to detect the prevalence of qnr and aac(6')-Ib-cr genes among clinical isolates of ciprofloxacin resistant Proteus spp. This cross-sectional study was carried out in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from July 2018 to June 2019. Fourty (40) Proteus spp. was isolated from 300 culture positive samples. Proteus mirabilis and Proteus vulgaris were identified by culture and biochemical test. Antibiotic susceptibility was performed by disc-diffusion technique. Quinolone resistance genes (qnrA, qnrB, qnrC, qnrD, qnrS and aac(6')-1b-cr) among ciprofloxacin resistant Proteus spp. were detected by PCR. Thirty (75%) ciprofloxacin resistant isolates were detected during disk-diffusion technique. Among them, quinolone resistance genes were found positive 11(36.67%) for aac(6')-Ib-cr, 6(20%) for qnrA, 5(16.67%) for qnrD, 4(13.33%) for qnrS and 3(10%) for qnrB genes. Co-existance of qnrA + aac(6')-Ib-cr and qnrD + qnrS were found in 3(10%) wound swab & pus and urine samples respectively followed by qnrA + qnrB in 2(6.67%) wound swab and pus and qnrA+qnrS in 1(3.33%) urine sample. The results of this study showed presence of high (66.67%) percentage of PMQR genes as well as high (30%) rate of co-carriage of the two genes among Proteus spp. isolates. The incidence of PMQR genes was found to be high which could be due to the increased prescription of fluoroquinolones. Thus, there is a need for rational usage of fluoroquinolones.

Distribution of Ciprofloxacin- and Azithromycin-Resistant Genes among Salmonella Typhi Isolated from Human Blood.

Context: Salmonella Typhi has developed resistance to different groups of antibiotics. Aims: The purpose of the present study was to assess the distribution of ciprofloxacin- and azithromycin-resistant genes among Salmonella Typhi isolated from human blood. Settings and Design: This cross-sectional study was conducted in the Department of Microbiology of a tertiary care hospital in Bangladesh from July 2019-June 2020. Subjects and Methods: Clinically suspected enteric fever patients, irrespective of age and gender, who attended the laboratory of the Department of Microbiology and outpatient department of Medicine of tertiary care hospital. Blood culture and sensitivity tests were done. The positive growth of Salmonella Typhi was identified by Gram staining, colony morphology, and biochemical test. Then, Salmonella Typhi was identified by using Salmonella-specific antisera. Final identification was made by using 16s rRNA by polymerase chain reaction (PCR). PCR was also done to detect quinolone and azithromycin resistance genes. Results: A total number of 83 samples yielded positive cultures, of which 50 isolated organisms were identified as Salmonella species; however, among these isolates, Salmonella Typhi was detected in 40 (48.2%) isolates. Among 12 ciprofloxacin-resistant isolates, 8 (66.67%) were positive for the gyrA gene, 1 (8.33%) was positive for the qnrB gene and qnrS gene, 2 (16.67%) were positive for aac (6´)-Ib-cr. Among 12 azithromycin-resistant isolates, 2 (16.66%) were positive for mphA and mefA genes, respectively. Conclusion: In conclusion, the gyrA, aac (6´)-Ib-cr, mphA, and mefA genes are found for the first time in tertiary care hospitals from the quinolones and azithromycin-resistant Salmonella Typhi.

Emergence of OXA-833 in Proteus Species at a Tertiary Care Hospital in Dhaka, Bangladesh.

CONTEXT: Proteus species are liable for multitude of infections and associated with resistance to routinely used antibiotics even to reserve drugs such as carbapenems. AIMS: The aim of this study was to detect the presence of MBL producers, including blaOXA-833 gene in Proteus spp. along with their antibiotic resistance pattern. SETTINGS AND DESIGN: This cross-sectional study was conducted in the Department of Microbiology of a tertiary care hospital of Bangladesh during July 2018 to June 2019. SUBJECTS AND METHODS: Proteus spp. was isolated from a total of 500 samples. Antibiotic susceptibility was performed by disk-diffusion technique. Minimum inhibitory concentration (MIC) of imipenem was determined by agar dilution method. Carbapenemase producers were phenotypically detected by double disc synergy (DDS) test, combined disc (CD) assay, and modified Hodge test (MHT). Carbapenemase genes (blaKPC, blaVIM, blaIMP, blaNDM-1, blaOXA-23, blaOXA-48-like/blaOXA-833, and blaOXA-58) among imipenem-resistant Proteus spp. were detected by polymerase chain reaction (PCR). Sequencing was performed to differentiate OXA-833 from OXA-48-like gene by capillary method, and the nucleotide sequence of OXA-833 has been deposited to GenBank. RESULTS: Ten (25%) imipenem-resistant isolates were detected during disk-diffusion technique, among them 60%, 70%, 50% carbapenemase producers were detected by DDS test, CD assay, MHT, respectively, and 70% by PCR. A significant increase in MIC was found between 8 and ≥128 µg/ml to imipenem. PCR revealed that 40% imipenem-resistant isolates were positive for blaNDM-1 and blaVIM followed by 20% for blaOXA-48-like/blaOXA-833 and blaOXA-23, respectively. Sequencing of blaOXA-48-like gene established the OXA-833 variant of class D carbapenemase encoding gene. CONCLUSION: The results of this study showed the presence of high proportion of carbapenemase enzyme-producing Proteus spp. in Bangladesh. blaOXA-833 is emerging in Bangladesh.

Intradermal Immunization with Heat-Killed Klebsiella pneumoniae Leading to the Production of Protective Immunoglobulin G in BALB/c Mice.

INTRODUCTION: Klebsiella pneumoniae superbug is emerging as a serious health concern as resistance to last-resort antibiotics spreads. To bypass the therapeutic molecules used today, the development of an immunoprophylactic safe approach is of great clinical relevance. This study was conducted to determine the protective efficacy of antibodies elicited by killed vaccine against multidrug-resistant (MDR) K. pneumoniae. MATERIALS AND METHODS: In this study, heat-killed MDR K. pneumoniae isolated from different clinical samples were employed for the intradermal immunization of 10 BALB/c mice. Two weeks after the third dose of immunization, the mice were intraperitoneally challenged with live K. pneumoniae and observed for 14 days. Tail blood was collected 7 days after each booster followed by cardiac puncture 14 days postchallenge. Bactericidal activity and antigen-binding capacity of the serum antibody produced by the vaccine were evaluated by serum bactericidal antibody (SBA) assay and ELISA, respectively. RESULTS: In this study, 80% survival rates were observed at 14 days postchallenge among the immunized mice. Regarding SBA assay, 100% bactericidal activity of the immunized mouse sera was observed using 50% guinea pig complement at 1:10 serum dilution after 3 h of incubation, and all the pre- and postchallenge immunized serum immunoglobulin G antibody had significantly higher optical density values comparing the control mice in ELISA. CONCLUSION: In our study, intradermal immunization with heat-killed MDR K. pneumoniae produced protective antibodies in BALB/c mice. These findings suggest that the use of a first-generation vaccine provides the supply of a larger number of candidate antigens for eliciting required immune response.

Quick Identification and Differentiation of Proteus spp. by PCR and RFLP Along with Their Antibiotic Resistance Pattern.

Different Proteus species are encountered in human infections and may vary with the type of infections they cause. So, the present study was conducted to detect species of Proteus by PCR and RFLP along with their antibiotic resistance pattern. This cross-sectional study was conducted in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh, from July 2018 to June 2019. A total of 500 wound swab and pus, urine and blood samples were tested for bacterial pathogens. Proteus spp. were identified and differentiated by biochemical test, PCR and RFLP. Antibiotic susceptibility was performed by disc-diffusion technique. Fourty Proteus spp. was isolated from 300 culture positive samples, giving 13.33% prevalence of Proteus infections. Proteus mirabilis and Proteus vulgaris were identified by culture, biochemical test, PCR and RFLP. The results were similar by both methods (biochemical tests and PCR). RFLP of 16S rRNA fragments digested with HaeIII revealed that P. mirabilis consisted of two bands at approximately 110 and 190 bp and P. vulgaris consisted of three bands at approximately 100, 180 and 220 bp. The proportion (80%) of P. mirabilis was more than P. vulgaris. Highest proportion (77.5%) of Proteus spp. was isolated from wound swab and pus followed by urine samples. A significant proportion of Proteus spp. was multidrug resistant (90%) and extensively drug resistant (37.5%). Fosfomycin was found the most sensitive drug followed by imipenem. This study provided an insight into antibiotic resistance pattern of Proteus spp. and showed high level resistance towards commonly used antimicrobial agents. PCR and RFLP may be suitable method to identify and differentiate species of Proteus and to treat them accordingly.

Observation of Changes in Helicobacter pylori Antigen and Antibody Positivity According to Non-Invasive Tests Before and After Helicobacter pylori Eradication Therapy in Symptomatic Patients.

BACKGROUND: Non-invasive tests can help with the diagnosis of Helicobacter pylori (H. pylori) infection and in determining patient prognosis following H. pylori eradication therapy. The aim of the study was to detect H. pylori antigens in the stool in symptomatic patients and to observe changes in the antigen test results following H. pylori eradication therapy. METHODS: A prospective study was conducted. Blood, urine and stool samples were collected from 62 dyspeptic patients. Anti-H. pylori IgM and IgG antibodies were detected in the serum by ELISA, anti-H. pylori IgG antibodies were detected in the urine by ICT and H. pylori antigens were detected in the stool by ELISA. Among the 62 patients, 39 (62.90%) were positive with all three methods. These 39 patients were asked to complete a 2-week course of medication and return after 6 weeks following completion of therapy to undergo repeated tests. In total, 3 dropped out of the study. RESULTS: Among the 62 dyspeptic patients, 41 (66.13%) were positive for serum IgG according to ELISA, 39 (62.90%) were positive for urine IgG according to ICT, 8 (12.90%) were positive for serum IgM according to ELISA, and 42 (67.74%) were positive for HpSA according to ELISA. After eradication therapy, 18 (50.00%) patients were positive for serum IgG, 19 (52.78%) were positive for urine IgG, 4 (11.11%) were positive for serum IgM and 5 (13.88%) were positive for HpSA. The difference in HpSA positivity before and after eradication therapy was statistically significant (P <0.05). CONCLUSION: This study involved non-invasive procedures that can be used as first-line screening tools for the detection of active H. pylori infection to observe the role of HpSA test in diagnosis and assessment of prognosis following eradication therapy for H. pylori.

Design, Operation and Optimization of Constructed Wetland for Removal of Pollutant.

Constructed wetlands (CWs) are affordable and reliable green technologies for the treatment of various types of wastewater. Compared to conventional treatment systems, CWs offer an environmentally friendly approach, are low cost, have fewer operational and maintenance requirements, and have a high potential for being applied in developing countries, particularly in small rural communities. However, the sustainable management and successful application of these systems remain a challenge. Therefore, after briefly providing basic information on wetlands and summarizing the classification and use of current CWs, this study aims to provide and inspire sustainable solutions for the performance and application of CWs by giving a comprehensive review of CWs' application and the recent development of their sustainable design, operation, and optimization for wastewater treatment. To accomplish this objective, thee design and management parameters of CWs, including macrophyte species, media types, water level, hydraulic retention time (HRT), and hydraulic loading rate (HLR), are discussed. Besides these, future research on improving the stability and sustainability of CWs are highlighted. This article provides a tool for researchers and decision-makers for using CWs to treat wastewater in a particular area. This paper presents an aid for informed analysis, decision-making, and communication. The review indicates that major advances in the design, operation, and optimization of CWs have greatly increased contaminant removal efficiencies, and the sustainable application of this treatment system has also been improved.

Phenotypic and Molecular Characterization of AmpC beta-lactamase Enzyme Producing Escherichia coli and Klebsiella species Isolated from A Tertiary Care Hospital in Bangladesh.

This cross-sectional study was conducted to determine the prevalence of AmpC beta-lactamase enzyme producing Escherichia coli and Klebsiella species in a tertiary care hospital of Bangladesh, as well as to observe the patterns of antibiotic resistance and AmpC beta-lactamase resistance genes among them. This study was conducted in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from January 2015 to December 2015. Total 166 Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca were isolated from urine, wound swab, pus, sputum and blood samples of patients of Dhaka Medical College Hospital. Antibiotic susceptibility test was performed by disk-diffusion technique. AmpC beta-lactamase producers were detected phenotypically by Modified three-dimensional test (MTDT). AmpC beta-lactamase genes (DHA, ACC, EBC, CIT, MOX, FOX) among the cefoxitin resistant Escherichia coli and Klebsiella species were detected by polymerase chain reaction (PCR). Sixty seven cefoxitin resistant Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca were isolated during disk-diffusion technique. Among the 67 cefoxitin resistant strains, 30(44.78%) AmpC beta-lactamase producers were detected by MTDT and 59(88.06%) were detected by PCR. The dominant genotype found was CIT (62.69%) followed by DHA (53.73%). The results of this study showed high proportion of AmpC beta- lactamase enzyme producing Escherichia coli and Klebsiella species in Bangladesh. Regular surveillance of antibiotic resistance should be done in every tertiary care hospital to prevent spread of these strains.

Nasal Colonization of Methicillin Resistant Staphylococcus aureus among Healthcare Providers in a Tertiary Care Hospital, Bangladesh.

Healthcare providers colonized with Staphylococcus aureus may transmit the organism to patients and community. This study was carried out to determine the rate of nasal colonization of Methicillin resistant Staphylococcus aureus (MRSA) and Vancomycin resistant Staphylococcus aureus (VRSA) among healthcare providers. This cross sectional study was conducted among healthcare providers in a tertiary care hospital, Bangladesh. Nasal swabs from anterior nares of 250 physicians, nurses, and helping staffs working in Dhaka Medical College Hospital were analyzed. Methicillin resistance among MRSA was detected by disc diffusion technique using oxacillin, cefoxitin disc and MIC of oxacillin and methicillin resistance was confirmed by PCR detecting mec-A gene. Considering PCR for mec-A gene as gold standard the sensitivity and specificity of both cefoxitin disc diffusion method and MIC of oxacillin was 100%. Cefoxitin disc diffusion method was better alternative of oxacillin disc diffusion method for detection of MRSA. Nasal colonization by S. aureus was found among 23.2% healthcare providers and 7.2% were colonized with MRSA and no VRSA was detected. MRSA colonization was detected among 5% physicians, 6.43% nurses and 16.67% of helping staffs. Isolated MRSA strains were highly resistant to ciprofloxacin (88.9%), gentamicin (77.8%), erythromycin (72.2%) and Co-trimoxazole (72.2%). All the isolated MRSA were sensitive to linezolid and vancomycin. Periodic screening of healthcare providers should be done to find out MRSA carrier and should be treated accordingly to terminate chain of transmission of the multi-drug resistant organism.

Laboratory Diagnosis of Bacterial Vaginosis and Potential Pathogens Other Than Group B Streptococcus in Vaginal Swab of Pregnant Women in Dhaka Medical College Hospital.

Pathogenic microorganisms are important cause of maternal and neonatal infections which are transmitted from colonized vagina of mother. The purpose of the present study was to detect the potential pathogens other than Group B Streptococcus in vaginal swab of pregnant women. This prospective cross sectional study was conducted from July 2013 to June 2014 at Dhaka Medical College Hospital, Dhaka, Bangladesh. A total of 224 vaginal swab samples were studied. Gram stain Nugent score was applied for all vaginal smear to detect bacterial vaginosis. Organisms were isolated and identified by wet film microscopy, Gram stain, biochemical tests, culture and PCR. Toxic shock syndrome toxin-1 gene and drug resistance genes such as mecA, vanA, vanB were detected among isolated Staphylococcus aureus. Antimicrobial susceptibility was done by disc diffusion method. Double disc synergy test was used to detect ESBL (Extended spectrum beta lactamases) producers. MIC (Minimum inhibitory concentration) of oxacillin and vancomycin were done for Staphylococcus aureus to detect MRSA (Methicillin resistant Staphylococcus aureus) and VRSA (Vancomycin resistant Staphylococcus aureus). Of the 224 samples, 44(19.64%) were Staphylococcus aureus, 22(9.8%) were Escherichia coli. Bacterial vaginosis was found in 12(5.36%) cases. Among the 9(21.43%) phenotypically identified ESBL producers, 4(18.18%) were Escherichia coli, 2(25%) were Klebsiella pneumoniae. Ninety six percent and 91% of the Escherichia coli were sensitive to colistin and imipenem. All the Klebsiella spp. was sensitive to colistin and all the Proteus spp. and the Pseudomonas aeruginosa were sensitive to imipenem and colistin. Of the 44 Staphylococcus aureus, 5(11.36%) were MRSA, 2(4.54%) were VRSA, 2MRSA were PVL gene positive and 2(4.54%) were positive for TSST-1 gene by PCR. All the isolated MRSA and VRSA were sensitive to linezolid. One of the two VRSA strains had MIC of vancomycin 64µg/ml and another had 128µg/ml. VRSA strains were positive for vanB gene, no VRSA was positive for vanA gene. Vaginal ecosystem study with the detection of pathogens can be helpful in the prevention of preterm delivery, premature rupture of membrane, chorioamnionitis, neonatal, puerperal and maternal-fetal infections.

Detection of Group B Streptococcus in Vaginal Swab of Pregnant Women by Culture and PCR and Their Antibiotic Susceptibility Pattern in a Tertiary Care Hospital of Bangladesh.

Group B Streptococcus (GBS) is an important cause of neonatal infection and transmitted from colonized vagina of mother. The purpose of the present study was to see the status of GBS infection in pregnant women. This prospective cross sectional study was conducted from July 2013 to June 2014 at Dhaka Medical College Hospital, Dhaka, Bangladesh. Total 224 vaginal swab samples were studied. Organisms were isolated and identified by Wet film microscopy, Gram stain, biochemical tests, culture and PCR. Of the 224 samples, 46(20.53%) were GBS positive. Highest proportion (33.78%) of GBS was found in 20-29 years of age group. Regarding GBS positivity majority (43.47%) were second gravid, 82.60% in 35-37 weeks of pregnancy, 64.04% were from middle income group, 39.13% were oral contraceptive pill (OCP) users. Hundred percent GBS were sensitive to penicillin, ampicillin, ceftriaxone and vancomycin. Most (46.43%) of the GBS were resistant to gentamycin followed by 35.72% to doxycycline and 28.57% to chloramphenicol. The sensitivity of PCR was 100%. Prevalence of GBS colonization was 20.53% among the pregnant women of Dhaka Medical College Hospital signifies GBS infection might be a silent clinical problem.