Distribution of adeB and NDM-1 genes in multidrug resistant Acinetobacter baumannii isolated from infected wound of patients admitted in a tertiary care hospital in Bangladesh.

BACKGROUND: The adeB gene in Acinetobacter baumannii regulates the bacterial internal drug efflux pump that plays a significant role in drug resistance. The aim of our study was to determine the occurrence of adeB gene in multidrug resistant and New Delhi metallo-beta-lactamase-1 (NDM- 1) gene in imipenem resistant Acinetobacter baumannii isolated from wound swab samples in a tertiary care hospital of Bangladesh. METHODS: A total of 345 wound swab samples were tested for bacterial pathogens. Acinetobacter baumannii was identified by culture and biochemical tests. Antimicrobial susceptibility pattern was determined by the disc diffusion method according to CLSI standards. Extended spectrum beta-lactamases were screened using the double disc synergy technique. Gene encoding AdeB efflux pump and NDM-1 were detected by Polymerase Chain Reaction (PCR). RESULTS: A total 22 (6.37%) Acinetobacter baumannii were identified from 345 wound swab samples and 20 (91%) of them were multidrug resistant. High resistance rates to some antibiotics were seen namely, cefotaxime (95%), amoxyclavulanic acid (90%) and ceftriaxone (82%). All the identified Acinetobacter baumannii were sensitive to colistin and 82% to imipenem. Two (9%) ESBL producing Acinetobacter baumannii strains were detected. adeB gene was detected in 16 (80%) out of 20 multidrug resistant Acinetobacter baumannii. 4 (18%) of 22 Acinetobacter baumannii were imipenem resistant. NDM-1 gene was detected in 2 (50%) of the imipenem resistant strains of Acinetobacter baumannii. CONCLUSION: The results of this study provide insight into the role of adeB gene as a potential regulator of drug resistance in Acinetobacter baumanni in Bangladesh. NDM-1 gene also contributes in developing such resistance for Acinetobacter baumannii.

Isolation of Extended Spectrum ß-Lactamase Producing Gram Negative Bacilli from Wound Swab with Their Antimicrobial Susceptibility Pattern.

Extended Spectrum ß-lactamases (ESBLs) producing organisms have become the major clinical concern worldwide. The present study was undertaken to see the frequency of ESBLs producing gram-negative bacilli with their antibiogram in post surgical wound swab collected over a period of 12 months from July 2011 to June 2012 at Dhaka Medical College Hospital. Among 200 samples 121(60.5%) gram negative bacilli and 52(26%) gram-positive bacteria were isolated. Escherichia coli (36.42%) was the most predominant gram-negative bacilli followed by Klebsiella species (9.83%) and Pseudomonas aeruginosa (8.67%). Thirty four (28.1%) isolates were detected as ESBLs producers by double-disc synergy test (DDST) and the prevalence among Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were 33.33%, 35.29% and 26.67% respectively. All the ESBL producing strains were sensitive to imipenem but they were significantly more resistant to ciprofloxacin, doxycycline, amoxiclav, co-trimoxazole, azithromycin and gentamycin than non-ESBLs producers (p<0.01). The finding suggests more effective strategies are needed to control the spread of these resistant organisms.

Prevalence of Hepatitis B Virus, Hepatitis C Virus, and HIV in Overseas Job Seekers of Bangladesh with the Possible Routes of Transmission.

Hepatitis and AIDS are major public health problem globally. The aim of this study was to determine the sero-prevalence of hepatitis B, C virus and HIV infection among Bangladeshi overseas job seekers. This cross sectional study was carried out in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from February 2013 to August 2013. A total of 2254 adult (18-45 years) male job seekers to Malaysia attending for health check up were enrolled. HBsAg, Anti-HCV, Anti-HIV were detected from venous blood by ELISA method using commercial kits. From the positive people, further history and information were collected by predesigned questionnaire. Prevalence of HBV was 2.35%, HCV was 0.13% and none was found positive for HIV. Prevalence of hepatitis was higher in the age group of 21-30 year and infection was more prevalent in married group. No significant relationship was found between hepatitis infection and religion, localities, profession. Only a few cases had history of possible major known route of transmission of virus. But most of them had history of taking injection or sharing blades in barber shop and history of circumcision. About 96% population had no history of hepatitis B vaccination. None was co-infected with HBV and HCV. Prevalence of hepatitis B virus infection in adult population appears to be on decline and hepatitis C and HIV infection is still low in Bangladesh. In majority of the positive person, routes of transmission of viruses were not well established.

Emergence of CTX-M-15 producing E. coli O25b-ST131 clone in a tertiary care hospital of Bangladesh.

BACKGROUND: Extended-spectrum ß-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.

Detection of potential pathogenic aerobic bacteria from egg shell and egg contents of hen collected from poultry.

This study was done to identify different pathogenic aerobic bacteria from egg shell and egg contents of hen. Egg shells and egg contents of 150 eggs collected from poultry were tested. Of 150 egg shells, 130 (86.67%) yielded growth of bacteria and 60 (40%) Esch. coli,.25 (16.67%) Providencia rettgeri, 5 (3.33%) Providencia alkalifaciens, 20 (13.33%) Citrobacter freundii, 10 (6.67%) Salmonella spp, 10 (6.67%) Enterobacter aerogenes were isolated. No bacteria were isolated from 150 egg contents. Total 14 (9.33%) Salmonella spp. from egg shells and 7 (4.67%) Salmonella spp. from egg contents were identified by PCR. Most of the identified serotypes were Salmonella Enteritidis (42.86% from egg shells and 71.43% from egg contents). All (100%) Salmonella Typhi and Salmonella Paratyphi A were sensitive to ciprofloxacin and ceftriaxone.

Molecular characterization and resistance profile of nosocomial Acinetobacter baumannii intensive care unit of tertiary care hospital in Bangladesh.

This study was designed to investigate the resistance profile along with the genetic background of resistance to beta-lactam antibiotics among the nosocomial A. baumannii in Bangladesh. A. baumannii was confirmed by detecting blaoXA-51-like. Antibiotic susceptibility was determined by disk diffusion method. Agar dilution method was used to determine MIC of ceftazidime and imipenem. All A. baumannii were phenotypically screened for ampC, ESBL and MBL production. Genetic markers of antibiotic resistance. such as blaampC, blaOXA-51, 23, 40, 58 and 143, blaKPc, blaMp, blavi and blaNDM-j, genetic environment around blaADc and ISAbal upstream of blaoXA, were evaluated by PCR. Twenty-four (96%) A. baumannii were considered as MDR. 96% A. baumanii were resistant to amoxiclav, ceftazidime, ciprofloxacin and cefoxitin, 92% to cefotaxime and piperacillin-tazobactam, 88% to cefepime, amikacin and imipenem, 52% to sulbactam- cefoperazone and 40% were resistant to aztreonam. Everything were sensitive to colistin. The distribution of several beta-lactamase genes such as blaoxa-51 (100%), blaADC-like (92%), blaNDM-i (92%), EBC group (84%), blaoxa-23 (76%), blavm (72%), blacpc (44%), DHA group (24%), blaoxa-58 (16%), ACC group (8%) and CIT group (4%) were observed among the 25 A. baumannii. This is the first reported plasmid mediated ampC beta-lactamases in A. baumannii. blaoxa-51 was positive in 100%, blandm-i in 95.45%, blaoxa-23 in 77.27%, blavim in 72.73%, blakpc in 50% and blaOXA-58 in 18.18% of imipenem resistant isolates. MDR profile of nosocomial A. baumannii would highlight the importance of standard guideline of antimicrobials use and infection control policy in the hospitals of Bangladesh.

Community acquired bacterial pneumonia: aetiology, laboratory detection and antibiotic susceptibility pattern.

This cross sectional study was conducted to identify the common bacterial causes of community acquired pneumonia (CAP) from sputum and blood by culture and polymerase chain reaction (PCR) and to evaluate the effectiveness of these tests. A total of 105 sputum and blood samples were collected from patients with pneumonia on clinical suspicion. Common causative bacterial agents of pneumonia were detected by Gram staining, cultures, biochemical tests and PCR. Among 55 sputum culture positive cases, a majority (61.82%) of the patients were in the age group between 21-50 years and the ratio between male and female was 2.5:1. Most (61.90%) of the cases were from the lower socio-economic group. Out of 105 samples, 23 (37.12%) were positive by Gram stain, 29 (27.62%) yielded growth in culture media and 37 (35.24%) were positive by PCR for Streptococcus pneumoniae and Haemophilus influenzae. Streptococcus pneumoniae was the most common aetiological agent (19.05%) followed by Klebsiella pneumoniae (13.33%), Haemophilus influenzae (8.57%) and Pseudomonas aeruginosa (5.71%). Multiplex PCR is a useful technique for rapid diagnosis of bacterial causes of pneumonia directly from sputum and blood. Considering culture as a gold standard, the sensitivity of PCR was 96.55% and specificity was 88.15%. More than 80% of Streptococcus pneumoniae isolates were found to be sensitive to ampicillin, amoxycillinclavulanate, and ceftriaxone. Susceptibilities to other antimicrobials ranged from 65% for azithromycin to 70% for levofloxacin. On the other hand, the Gram negative organisms were more sensitive to meropenem, ceftriaxone, amoxycillin-clavulanate and amikacin.

Diagnosis of common bacterial causes of urethritis in men by Gram stain, culture and multiplex PCR.

Urethritis is one of the most important causes of morbidity and mortality in developing countries. The aim of this study was to detect common bacterial causes of urethritis in men by Gram stain, culture and multiplex PCR.185 male patients who presented at the Skin and venereal clinic of the Dhaka Medical College, Bangladesh with clinical symptoms suggestive of urethritis were enrolled in this study. Urethral discharges were tested for detection of Neisseria gonorrhoeae by Gram stain, culture and PCR. Multiplex PCR assay was done to detect DNA of Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma genitalium. Out of 185 participants, 30.27% and 14.6% were infected by Neisseria gonorrhoeae and Chlamydia trachomatis respectively. None of the individuals was found positive for either Ureaplasma urealyticum or Mycoplasma genitalium. Among the Neisseria gonorrhoeae positive patients 27.57% were positive from Gram stain, 26.49% were culture positive, 30.27% were positive by PCR (p<0.001). 32.65% of the Neisseria gonorrhoeae isolates were penicillinase producers and 83.67% were susceptible to ceftriaxone. Considering culture as the gold standard, the sensitivity and specificity of PCR for the detection of Neisseria gonorrhoeae was 100%, and 94.85% respectively with an accuracy of 96.22%. 3.73% of the 134 smear negative and 5.15% of the 136 culture negative samples were positive by PCR. PCR was the most sensitive and rapid method for the diagnosis of urethritis. Multiplex PCR may be a useful approach to laboratory diagnosis of urethritis in men for its high sensitivity and specificity.

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.

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.

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.

Antimicrobial susceptibility pattern of extended spectrum beta-lactamase producing gram-negative bacteria isolated from wound and urine in a tertiary care hospital, Dhaka City, Bangladesh.

From a total of 320 bacterial samples from wound swab and urine 169 (53%) gram-negative bacteria were isolated, of which 42 (25%) extended-spectrum beta-lactamase (ESBL) producers were detected by double-disk synergy test. ESBL producers were significantly more resistant against amoxiclav, Co-trimoxazole, ciprofloxacin, amikacin and gentamicin than non-ESBL producers. Among the 42 ESBL producers, 76% were positive for blaCTX-M and 43% were positive for blaOXA, with blaCTX-M predominantly (97%) observed in E. coli and blaOXA predominantly (80%) in Pseudomonas spp. Class 1 integron was found in 75% of blaCTX-M positive and 56% of blaOXA positive strains. Combinations of ESBL genes and class 1 integron were observed in 29 (69%) of the ESBL producers. The findings of this study infer that CTX-M and OXA producers are emerging in Bangladesh and we report the presence of blaOXA for the first time in Bangladesh.

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.

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.

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 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.

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.

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.