Imipenem-resistant Pseudomonas Research Articles

Evaluation of different phenotypic techniques in detection of metallo-betalactamases in pseudomonas aeruginosa

Metallo-beta-lactamase (MBL) producing Pseudomonas is a worrisome pathogen to hospital infection control due to production of resistance to multiple antibiotics. So, treatment options are narrowed down to only few antibiotics which will result in high morbidity and mortality. This study was conducted with the aim to detect prevalence of MBL producing Pseudomonas aeruginosa and to compare the different phenotypic methods for the detection of MBL production in Imipenem resistant clinical isolates of Pseudomonas aeruginosa. : In this prospective study total of 14,145 different clinical samples received from different wards. Out of which 804 Pseudomonas aeruginosa were isolated and antibiotic sensitivity testing was done by Kirby-Bauer disc diffusion method using CLSI guidelines. These were evaluated for Carbapenems resistance and MBL production. Imipenem resistant strains were subjected to screening tests like Double-disc synergy test, Combined disc diffusion test (CDT) and Modified-Hodge test. : In our study out of 804 isolates,153(19.02%) isolates are resistant to Imipenem. Out of 153 Imipenem resistant isolates, Combined disc diffusion test was positive in 100%, Double disc synergy test in 76.5% and Modified-hodge test in 84.15% isolates.: Combined disc diffusion test is very sensitive, cost effective and convenient screening test for detection of MBL producing Pseudomonas aeruginosa. So, all Imipenem resistant Pseudomonas isolates should be regularly screened for detection of MBL by Combined disc diffusion test (CDT) to prevent spread of resistance, longer hospital stay and treatment failure.

A STUDY OF PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF NON FERMENTER GRAM NEGATIVE BACILLI ISOLATED FROM VARIOUS CLINICAL SAMPLES AT A TERTIARY CARE CENTER, JAIPUR

Introduction: Non-fermentative Gram-negative bacilli (NFGNB) are occasionally involved in infectious diseases pathology, but have shown resistance to multiple antibiotics and the capability to gain new resistance factors in the hospital environment. The present study was aimed to investigate the prevalence of Metallo-beta-lactamase (MBL) producing non-fermenters among the carbapenem-resistant isolates. AMethods: total of 200 NFGNB isolates from various clinical samples were analyzed by using different standard microbiological techniques and antimicrobial susceptibility using Kirby-Bauer method. MBL detection was performed by Modied Hodge test (MHT), imipenem-EDTA combined disc test, and modied Carbapenemase inactivation method (mCIM). In our study, 200 NFGNB isolates recovered from various clinical samples.Results: Pseudomonas aeruginosa was the most common NFGNB, accounting 112 (56%), followed by Acinetobacter baumannii 56 (28%), Burkholderia species 26 (13%) and other rare nonfermenter Gram negative bacilli 6 (3%). NFGNB isolates were maximally isolated from blood samples 73 (36.5%) followed by respiratory samples 46 (23%), urine 40 (20%), pus 37 (18.5%) and CSF 4 (2%). All the NFGNB isolates were susceptible to polymyxin B, colistin (100%), and cefoperazone + sulbactam (45.53%). Out of 112 Pseudomonas isolates, 77(68.75%) were imipenem resistant and of 56 Acinetobacter isolates, 35(62.5%) were imipenem resistant. Out of 77 imipenem resistant Pseudomonas 70 (90.9%) were MBL producers and out of 35 imipinem resistant Acinetobacter spp 32 (91.42%) were MBL producers. NFGNB are now emerging asConclusion: organisms of nosocomial infections. The use of broad-spectrum antibiotics should be avoided and quick detection and efcient infection control measures are essential to prevent the further spread of MBLs to other Gram-negative bacilli. Detection of MBL production and rationale antibiotic usage are the most important factors which control the gradually increasing NFGNB related infections

Phenotypic detection and molecular characterization of carbapenem-resistant Enterobacteriaceae at a tertiary care center

Background: Carbapenem-resistant Enterobacteriaceae (CRE) is of utmost clinical importance because they challenge the armamentarium of the treating clinicians, hampering current treatment strategies. Aim: The aim of the study is to detect carbapenemase-producing Enterobacteriaceae by phenotypic and molecular methods. Materials and Methods: Nonrepetitive isolates of Enterobacteriaceae were identified by conventional phenotypic methods from various clinical samples. All these isolates were screened for carbapenem resistance by meropenem (10μg) or ertapenem (10μg) disc. All the isolates which were found to be carbapenem-resistant by screening test were subjected to phenotypic confirmatory test in the form of modified Hodge test (MHT). These isolates were then subjected to polymerase chain reaction for the detection of various carbapenemase-producing genes, namely New Delhi metallo-β-lactamase 1 (NDM), verona integron-encoded metallo-β-lactamase (VIM), imipenem-resistant Pseudomonas (IMP), KPC, and OXA-48. Results: Out of 1254 isolates of Enterobacteriaceae, 230 isolates (18.3%) were found to be positive for carbapenemase production by screening test. A total of 150 out of 230 isolates (65.2%) tested positive for carbapenemase production by MHT. Out of these 150 phenotypically confirmed carbapenemase-producing isolates, blaNDM gene was found in 85, blaVIM in 32, and blaIMP in 22 isolates. blaOXA-48 and blaKPC genes were not found in any isolate. Moreover, there were 19 isolates, in which no gene was detected. Conclusion: The prevalence of phenotypically confirmed carbapenemase resistance among Enterobacteriaceae is 11.96% (150/1254). Genes responsible for carbapenemase production are widely prevalent in Enterobacteriaceae Routine detection will help in the management of these broadly-resistant pathogens and implementation of appropriate infection control measures, thus limiting their spread.

Reunion Island, a sentinel territory for antimicrobial-resistant bacteria surveillance in the South-Western Indian Ocean: a retrospective survey using hospitalized patient screening, 2015\u20132017

BackgroundIn 2015, antimicrobial resistance was identified as a public health priority for the South-Western Indian Ocean (SWIO) (i.e. Comoros, Madagascar, Mauritius, Mayotte (France), Reunion Island (France), and Seychelles). However, in 2020, colonization rates of antimicrobial-resistant bacteria (ARB) in human populations on most islands in SWIO were still not known and neither hospital nor community colonization rates had been estimated. The aim of this study was to estimate the prevalence of colonization of six ARB groups in hospitalized patients residing in the SWIO territories. The six groups comprise extended-spectrum betalactamase producing Enterobacteriaceae (ESBL-E), carbapenem-resistant Enterobacteriaceae (CRE), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and both ceftazidime and/or imipenem-resistant Acinetobacter spp. (ACB), and ceftazidime and/or imipenem-resistant Pseudomonas spp. (PSA)).MethodsBased on comprehensive hospital laboratory ARB screening data, we provide the first estimation of ARB colonization rates in hospitalized patients residing in SWIO (2015–2017). Using ARB colonization rates in Reunion Island (France) as the reference for estimating odds ratio, we identified at risk patients based on their territory of residence.ResultsThe survey pointed to significantly higher overall ARB colonization rates in patients from Comoros, Madagascar, Mayotte, and Seychelles compared to Reunion Island as the reference. Extended-spectrum betalactamase producing Enterobacteriaceae was found to be the most common ARB group colonizing patients from SWIO territories. The highest MRSA colonization rates were observed in patients from Mayotte and Seychelles. Colonization by carbapenem-resistant Enterobacteriaceae (CRE) was highest in patients from Mauritius.ConclusionThese results identify high ARB colonization rates in hospitalized patients from SWIO territories that require further investigation, particularly CRE in Mauritius and MRSA in Seychelles and Mayotte. This study is the first step toward the implementation of a broader regional ARB surveillance system.

Detection of prevalence of metallo-beta lactamases in clinical isolates of imipenem resistant Pseudomonas aeruginosa from neonatal septicaemia cases in a tertiary hospital in Odisha, India

Background: Pseudomonas aeruginosa is a clinically troublesome gram-negative pathogen that causes both opportunistic infections and nosocomial outbreaks. Metallo beta lactamase have recently emerged as a worrisome resistance mechanism. Carbapenems had been the drug of choice for the infections caused by most penicillin- or cephalosporin-resistant gram-negative bacteria due to its broad-spectrum activity and stability to hydrolysis by most beta-lactamases. This does not hold good anymore due to rapid uprise of MBL producing strains. The current research covered 163 hospitalized cases of neonatal septicaemia from which Pseudomonas aeruginosa is isolated in the Paediatric Department of KIMS, Bhubaneswar. The study aimed at detecting the prevalence of metallo-beta lactamases in clinical isolates of imipenem resistant Pseudomonas aeruginosa from neonatal septicemia cases and to establish the antibiogram of Imipenem-resistant P. aeruginosa these cases. Methods: Clinical samples obtained from suspected cases of neonatal septicemia were first cultured by conventional methods and then identification was done by VITEK-2 instrument. Metallo beta lactamase (MBL) production was done by combined disc synergy test (CDST) using imipenem and EDTA (CDST-IPM) and double disc synergy test (DDST) using IPM and EDTA (DDST-IPM). Results: Among 1510 processed clinical specimens from cases of neonatal septicaemia; 637 (42.18%) showed positive growth of various clinically significant pathogens. Out of them in 163 (25.58%) cases Pseudomonas spp. was isolated. Of these, a total of 95 (58.28%) Pseudomonas spp. was found resistant to imipenem. All imipenem-resistant Pseudomonas isolates were positive for MBL by CDST imipenem-EDTA (CDST-IPM) method, whereas 89 (93.68%) were positive by DDST-IPM method, respectively. Pseudomonas aeruginosa was mostly isolated from endotracheal tube aspirate (57.89%) followed by pus (56.41%). Out of the 95 cases of MBL-producing Pseudomonas; 46 (48.42%) isolates showed the maximum susceptibility to piperacillin-tazobactam combination. All MBL-producing Pseudomonas isolates were resistant to ceftriaxone.Conclusions: MBL-producing Pseudomonas is found to be highly prevalent in our hospital, which is one of the major causes of multidrug resistance and need regular surveillance and strict adherence to a robust antibiotic policy.

Microorganisms Profile and their Antimicrobial Resistance Pattern Isolated from the Lower Respiratory Tract of Mechanically Ventilated Patients in the Intensive Care Unit of A Tertiary Care Hospital in Dhaka

Objective: Aim of the study was to know the microorganisms profile and determine the antibiotic resistance pattern of the LRT isolates from mechanically ventilated (MV) patients admitted to the ICU. This prospective observational study was done in Department of Critical Care Medicine (ICU) of BIRDEM General Hospital Dhaka from July, 2011 to December, 2011.Methods: Blind Tracheal Aspirate or Broncho Alveolar Lavage or both from 110 consecutive patients (total 130 samples) admitted to the ICU requiring MV were cultured, identified, and antibiotic sensitivity was performed by standard methods.Results: A total of 130 samples were analyzed. Growth was obtained in 93.8% of the samples yielding 143 organisms. Many (21 samples) yielded more than one organism. The major organism isolated were Acinetobacter sp. (54.5%), Pseudomonas sp.(14.7%), Klebsiella sp. (7.7%).Candida sp. (7.0%), Staphylococcus aureus(7.0%), Escherichia coli (4.9%).Proteus and Flavobacterium accounted for 4.2% of the isolates. All the isolates were highly resistant (>90%) to cephalosporins and >70% to fluoroquinolones. The frequency of third generation cephalosporin resistant E. coli, Klebsiellaand imipenem resistant Pseudomonas and Acinetobacter were>90%. Acinetobacter was remarkably resistant to most antibiotics including imipenem (>90% resistant) and Piperacillin+Tazobactum (>85% resistant), but most of the members of the Enterobacteriacae group and Acinetobacter showed maximum sensitivity to colistin (80%-100%).Conclusion: Nonfermenters Gram Negative Bacilli (GNB)-Acinetobacter sp. & Pseudomonas sp. are the most common etiological agents of LRT infections in ICU. There is an alarmingly high rate of resistance to cephalosporin and ²â-lactamase inhibitor group of drugs. Colistin was found to be the most sensitive drug against all GNB.J MEDICINE July 2016; 17 (2) : 91-94

Discovery of MK-7655, a β-lactamase inhibitor for combination with Primaxin®

β-Lactamase inhibitors with a bicyclic urea core and a variety of heterocyclic side chains were prepared and evaluated as potential partners for combination with imipenem to overcome class A and C β-lactamase mediated antibiotic resistance. The piperidine analog 3 (MK-7655) inhibited both class A and C β-lactamases in vitro. It effectively restored imipenem’s activity against imipenem-resistant Pseudomonas and Klebsiella strains at clinically achievable concentrations. A combination of MK-7655 and Primaxin® is currently in phase II clinical trials for the treatment of Gram-negative bacterial infections.

Intravascular catheter related infections and antimicrobial susceptibility pattern of isolated bacteria in a tertiary care hospital of Bangladesh

The aim of this study was to evaluate the rate of bacterial colonisation and catheter related blood stream infections (CRBSI) together with the antibiotic susceptibility patterns in a tertiary care hospital. CRBSI was detected with semi-quantitative and quantitative methods. The antimicrobial susceptible patterns of the isolated organisms were performed by Kirby Bauer disk diffusion method. The rate of catheter colonisation and CRBSI were 42.1% and 14% (16.1/1000 catheter days) respectively. The most common causative pathogens were Pseudomonas sp. (23.7%), Acinetobacter sp. (18.4%), Staphylococcus aureus (13.2%) and Enterobacteriaceae (10.5%). The rate of isolation of methicillin resistance S. aureus, imipenem resistant Pseudomonas sp. and extended spectrum β lactamase producing Enterobacteriaceae were 60%, 44.0% and 100%. The result of this study would be useful for control and treatment of CRBSI.

Phenotype detection of metallo-β-lactamase among the imipenem resistant Psudomonas and Acinetobacter in the tertiary care hospitals of Dhaka city

Metallo beta lactamases (MBL) are enzymes that have wide spread of activity and they confer a high level of resistance to all b-lactams including carbapenem, except aztreonam [1]. MBLs require divalent zinc ion for their enzymatic activity which is not diminished by serine b lactamase inhibitors like salbactam, tazobactam, clavulinic acid etc but is inhibited by metal chelators like EDTA and thiol based compounds such as 2-mercaptopropionic acid (2-MPA), 10-phenanthroline, calcium dipicholinate etc [2]. They have constant and efficient carbapenemase activity. This MBL production is typically associated with resistance to aminoglycosides and fluoroquinolones further compromising therapeutic options [3]. There are no standard methods for the detection of MBL production in gram negative organism in routine Microbiology practice. The present study was undertaken to evaluate the screening tests like double disk synergy test (DDST) and disk potentiation test (DPT) using ceftazidime (CAZ) and imipenem (IPM) disks with chelating agents like EDTA and 2-MPA. A total of 132 Pseudomonas and 76 Acinetobacter isolates were obtained from Bangabandhu Sheikh Mujib Medical University (BSMMU), Bangladesh Institute of Research and Rehabilitation for Diabetes, and Endocrine and Metabolic disorders (BIRDEM) hospitals of Dhaka city. A total of 53 and 29 IPM resistant Pseudomonas and Acinetobacter isolates respectively were selected. EDTAIPM micro dilution minimum inhibitory concentration (EDTA-IPM micro dilution MIC) method detected MBL in 44 (83%) IPM resistant Pseudomonas and 19(65.5%) Acinetobacter isolates. DDST with CAZ-0.1M EDTA and CAZ-2-MPA detected MBL in 73.6% and 67.9% of IPM resistant Pseudomonas and 55.2% and 48.3% of Acinetobacter isolates respectively. The detection rate was 67.9% and 66.1% in Pseudomonas and 51.7% and 44.8% in Acinetobacter isolates by EDTA-IPM and IPM-2MPA methods respectively. In comparison to DDST, DPT with 0.1M EDTA showed higher sensitivity (89.7%) and specificity (100%) for detection of MBL in Pseudomonas and Acinetobacter. Isolates were also tested for AmpC b lactamase by DPT using chelating agent aminophenyl boronic acid (APB) and it detected AmpC b lactamase in 6.9% and 21.1% MBL positive Pseudomonas and Acinetobacter respectively. MBL producing Pseudomonas and Acinetobacter are emerging in our country. Rapid detection of these MBLs is necessary to institute appropriate treatment and effective infection control measures. Simple screening test like DPT using CAZ/IPM with 0.1M EDTA can be introduced into the routine clinical laboratories for their early detection.

Simple Screening Tests for the Detection of Metallo-β-Lactamase (MBL) Production in Clinical Isolates of <i>Pseudomonas</i> and <i>Acinetobacter</i>

There are no standard methods for the detection of metallo-β-lactamase (MBL) production in gramnegative organism in routine microbiology practice. The present study was undertaken to evaluatethe screening tests like double disk synergy test (DDST) and disk potentiation test (DPT) usingceftazidime (CAZ) and imipenem (IPM) disks with chelating agents like EDTA, 2-mercaptopropionicacid (2-MPA). A total of 132 Pseudomonas and 76 Acinetobacter isolates were obtained fromBangabandhu Sheikh Mujib Medical University (BSMMU) and Bangladesh Institute of Researchand Rehabilitation for Diabetes, Endocrine and Metabolic Disorders (BIRDEM) hospitals of Dhakacity. A total of 53 and 29 IPM resistant Pseudomonas and Acinetobacter isolates were selected.EDTA-IPM microdilution minimum inhibitory concentration (EDTA-IPM MIC) method detectedMBL in 44 (83%) IPM resistant Pseudomonas and 19 (65.5%) Acinetobacter isolates. DDST withCAZ-0.1M EDTA and CAZ-2-MPA detected MBL in 73.6% and 67.9% of IPM resistant Pseudomonasand 55.2% and 48.3% of Acinetobacter isolates respectively. The detection rate was 67.9% and66.1% in Pseudomonas and 51.7% and 44.8% in Acinetobacter isolates by EDTA-IPM and IPM-2-MPA methods respectively. In comparison to DDST, DPT with CAZ-0.1M EDTA showed highersensitivity (89.7% ) and specificity (100%) for detection of MBL in Pseudomonas and Acinetobacter.The results showed that simple screening tests like DPT with 0.1M EDTA was able to detect MBLproducing Pseudomonas and Acinetobacter from clinical samples with high sensitivity and specificity.Ibrahim Med. Coll. J. 2010; 4(1): 26-30DOI: 10.3329/imcj.v4i1.5932

Study of resistance to carbapenems of Pseudomonas aeruginosa in 5 Beijing hospitals

Objective To investigate the molecular mechanism of resistance to carbapenems in Pseudomonas aeruginasa from 5 teaching hospitals in Beijing. Methods A total of 213 non-duplicate imipenem-resistant Pseudomonas aernginosa (IRPA) isolates were collected from 5 hospitals in Beijing from June 2004 to December 2005. The minimal inhibitory concentrations (MICs) of meropenem, imipenem and others antibiotics were determined by agar dilution method. Disk diffusion test was used for screening metalloenzymes. The bla IMP,bla VIM and OprD2 genes were amplified by PCR and only sequenced. Results Out of 213 isolates, OprD2 loss was detected in 84 isolates and IMP-1 enzyme was detected in 6 isolates simultaneously. Thirteen IRPAs only produced IMP-1 and 2 isolates only produced VIM-2. Conclusion OprD2 loss and metallo-β-lactamuse production are the parts of the mechanisms of resistance to carbapenems in Pseudomonas aeruginosa in Beijing. Key words: Pseudomonas aeruginosa; Imipenem-resistant; Metallo-β-lactamase; OprD,2

METALLO-β-LACTAMASE-PRODUCING CLINICAL ISOLATES OF ACINETOBACTER SPECIES AND PSEUDOMONAS AERUGINOSA FROM INTENSIVE CARE UNIT PATIENTS OF A TERTIARY CARE HOSPITAL

Prompt detection of metallo-β-lactamase (MBL) producing isolates is necessary to prevent their dissemination. Frequency of MBLs producing strains among multidrug resistant (MDR) Acinetobacter species and Pseudomonas aeruginosa was evaluated in critical care patients using imipenem-EDTA disk method. One hundred MDR Acinetobacter spp. and 42 Pseudomonas aeruginosa were checked for MBL production, from January to June 2001. MBL was produced by 96.6 % of imipenem-resistant Acinetobacter isolates, whereas 100% imipenem-resistant Pseudomonas aeroginosa isolates were MBL producers. Carbapenem resistance in MDR Acinetobacter spp. and Pseudomonas aeruginosa isolates in this study was due to MBLs. This calls for strict infection control measures to prevent further dissemination.

How Important Is the Environment in the Emergence of Nosocomial Antimicrobial-Resistant Bacteria?

in incidence. As evidenced by the Centers for Disease Control and Prevention National Healthcare Safety Network collection of data across a large number of hospitals, resistance rates for vancomycinresistant enterococci (VRE), methicillinresistant Staphylococcus aureus, imipenemresistant Pseudomonas aeruginosay and cephalosporin-resistant Escherichia coli and Klebsiella species continue to increase [1]. These increases in antibiotic-resistant bacteria continue to occur despite efforts to contain them by numerous parties, including the Centers for Disease Control and Prevention, Veterans Health Administration, public interest groups, quality improvement administrators, antimicrobial stewardship teams, and hospital epidemiologists. Figure 1 is a theoretical model that

Metallo-β-lactamase-producing clinical isolates of <i> Acinetobacter</i> species and <i> Pseudomonas aeruginosa</i> from intensive care unit patients of a tertiary care hospital

Prompt detection of metallo-beta-lactamase (MBL) producing isolates is necessary to prevent their dissemination. Frequency of MBLs producing strains among multidrug resistant (MDR) Acinetobacter species and Pseudomonas aeruginosa was evaluated in critical care patients using imipenem-EDTA disk method. One hundred MDR Acinetobacter spp. and 42 Pseudomonas aeruginosa were checked for MBL production, from January to June 2001. MBL was produced by 96.6 % of imipenem-resistant Acinetobacter isolates, whereas 100% imipenem-resistant Pseudomonas aeroginosa isolates were MBL producers. Carbapenem resistance in MDR Acinetobacter spp. and Pseudomonas aeruginosa isolates in this study was due to MBLs. This calls for strict infection control measures to prevent further dissemination.

Bla(VIM-2) cassette-containing novel integrons in metallo-beta-lactamase-producing Pseudomonas aeruginosa and Pseudomonas putida isolates disseminated in a Korean hospital.

We investigated the phenotypic and genetic properties of metallo-beta-lactamase-producing Pseudomonas isolates collected at a tertiary-care hospital in Korea since 1995. The prevalence of imipenem resistance among Pseudomonas aeruginosa isolates reached 16% in 1997, when 9% of the resistant organisms were found to produce VIM-2 beta-lactamase, a class B enzyme previously found only in P. aeruginosa isolates from Europe. VIM-2-producing isolates of Pseudomonas putida were also detected. Resistance was transferable from both these species to P. aeruginosa PAO4089Rp by filter mating, although the resistance determinant could not be found on any detectable plasmid. Serotyping showed that many of the VIM-2-producing P. aeruginosa isolates belonged to serotypes O:11 and O:12, and pulsed-field gel electrophoresis of XbaI-digested genomic DNA revealed that many had identical profiles, whereas the P. putida isolates were diverse. Sequencing showed that the bla(VIM-2) genes resided as cassettes in class 1 integrons. In contrast to previous VIM-encoding integrons, the integron sequenced from a P. aeruginosa isolate had bla(VIM) located downstream of a variant of aacA4. bla(VIM) also lay in a class 1 integron in a representative P. putida strain, but the organization of this integron was different from that sequenced from the P. aeruginosa strain. In conclusion, the metallo-beta-lactamase produced by these imipenem-resistant Pseudomonas isolates was VIM-2, and the accumulation of producers reflected clonal dissemination as well as horizontal spread. Strict measures are required in order to control a further spread of resistance.

Phenotypic detection of metallo-β-lactamase among the clinical isolates of imipenem resistant <i>Pseudomonas</i> and <i>Acinetobacter</i> in tertiary care hospitals of Dhaka city

The rapid spread of Metallo-β-lactamase (MBL) producing Gram negative bacilli represents a matter of great concern worldwide. The study analyzed the occurrence of MBL production in carbapenem resistant Pseudomonas and Acinetobacter isolates over one year period. A total of 132 Pseudomonas and 76 Acinetobacter isolates were obtained from two tertiary care hospitals of Dhaka city. A total of 53 Pseudomonas and 29 Acinetobacter isolates were selected because of their resistance to carbapenem specially imipenem (IPM). Screening for MBL production was performed in these isolates by IPM-EDTA microdilution MIC method. 44 (83%) IPM resistant Pseudomonas and 19 (65.5%) Acinetobacter isolates were MBL producer by IPM-EDTA microdilution MIC method. These results suggest that MBL producing Pseudomonas and Acinetobacter isolates are emerging in our country and it is essential to screen carbapenem resistant isolates for MBL production. DOI: 10.3329/imcj.v4i2.6498Ibrahim Med. Coll. J. 2010; 4(2): 63-65

Metallo-ß-Lactamase Producing Pseudomonas species in a Tertiary Care Hospital of Dhaka City

Among the various beta-lactam antibiotics, carbapenems are the most potent and have been reserved for use in treating infections caused by multi-drug resistant (MDR) Gram negative bacilli, especially Pseudomonas. They are effective even against Extended Spectrum beta-lactamase (ESBL) and Amp C b-lactamase producing bacteria. The clinical utility of carbapenems is under threat with the emergence of carbapenem resistant bacteria due to production of carbapenem hydrolyzing metallo-beta-lactamase (MBL) which confers high-level resistance to all b-lactam antibiotics except aztreonam. The prevalence of MBLs have been studied in many countries but not been reported in Bangladesh. The purpose of the study to determine the presence of MBLs producing Pseudomonas in clinical samples from a tertiary care hospital. MBLs producing Pseudomonas in various clinical samples of an urban hospital of Dhaka city was investigated over a 6-month period (January 2009-June 2009). EDTA-IMP agar dilution minimum inhibitory concentration (MIC) reduction method was employed to detect MBL producing Pseudomonas sp. Out of 44 Pseudomonas isolates 08 (18.2%) were sensitive and 23 (52.3%) were resistant to imipenem while 13 (29.5%) were intermediate resistant (MIC = 8 μg/ml) to imipenem. All Pseudomonas showing intermediate resistance to imipenem were found sensitive by disc diffusion method. MBL phenotype was detected in 43%(10 out of 23) imipenem resistant Pseudomonas spp. while the rate was 61%(08 out of 13) is intermediate resistant strains by EDTA-IMP agar dilution MIC method. The results of the study indicated high prevalence of MBL producing Pseudomonas spp. in our hospital environment. Early detection of these MBL producing Pseudomonas is necessary to institute appropriate treatment and effective infection control measures. Key words: Metallo-ß-lactamase, Pseudomonas species, Gram negative bacilli. DOI: http://dx.doi.org/10.3329/bjmm.v4i1.8469 BJMM 2011; 4(1): 43-45

Bacterial profile and their antimicrobial resistance pattern in an intensive care unit of a tertiary care hospital of Dhaka

Critically ill patients admitted in intensive care units (ICU) are always at a higher risk of developing infections with various antibiotic resistant organisms. The objective of this study was to know the antibiotic resistance pattern of the common isolates from blood, urine, respiratory secretions and pus/wound swab of patients admitted in ICU at BIRDEM (Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorder) hospital, during a one year period from March 2006 to February 2007. A total of 1660 samples were analyzed. Growth was obtained in 34% of the samples yielding 632 organisms. The major organism isolated were Pseudomonas sp. (29.1%), Acinetobacter sp. (27.5%), Candida sp. (12.8%), Escherichia coli (10.3%) and Klebsiella sp. (9.7%). Staphylococcus aureus, Enterobacter sp, Citrobacter sp, Enterococcus sp, Providencia sp and Serratia sp accounted for 10.6% of the isolates. All the isolates were highly resistant (>80%) to cephalosporins and fluoroquinolones. The frequency of third generation cephalosporin resistant E. coli, Klebsiella and imipenem resistant Pseudomonas and Acinetobacter were >50%. Acinetobacter was remarkably resistant to most antibiotics including imipenem (>70% resistant), but most of the members of the Enterobacteriacae group showed maximum sensitivity to imipenem (50%-94%). The findings of this study might help clinicians to formulate their first line empirical antibiotic treatment regimens for the patients admitted in ICUs. Key words: Intensive care units; antimicrobial resistance pattern; bacterial profile. DOI: 10.3329/imcj.v4i2.6499Ibrahim Med. Coll. J. 2010; 4(2): 66-69