scholarly journals Prevalence and characterisation of carbapenemase encoding genes in multidrug-resistant Gram-negative bacilli

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259005
Author(s):  
Sayran Hamad Haji ◽  
Safaa Toma Hanna Aka ◽  
Fattma A. Ali

Background Emerging worldwide in the past decade, there has been a significant increase in multidrug-resistant bacteria from serious nosocomial infections, especially carbapenemase-producing Gram-negative bacilli that have emerged worldwide. The objective of this study is to investigate carbapenem resistance in Gram-negative bacilli bacteria using phenotypic detection, antimicrobial resistance profiles and genotypic characterisation methods. Methods 200 Gram-negative bacilli isolates were collected from different clinical specimens. All clinical samples were exposed to isolation and identification of significant pathogens applying bacteriological examination and an automated Vitek-2 system. The isolates were subjected to susceptibility tests by the Vitek-2 automated system and those isolates that were resistant to beta-lactam drugs, including carbapenems, third-generation cephalosporines or cefoxitin, were selected for phenotyping using Carba plus disc system assay for detection of carbapenemase-producing isolates. These isolates were further confirmed by molecular detection. PCR was used for the detection carbapenem-resistant genes (OXA-48, IMP, NDM, VIM, and KPC). Results 110 (55%) of 200 Gram-negative bacilli were identified as beta-lactam-resistant isolates. The frequency of carbapenem-resistant isolates was calculated to be 30.9% (n = 34/110). A collection totalling 65/110 (59%) isolates were identified as carbapenemase producers by phenotypic method. Moreover, among the 65 carbapenemase-producing Gram-negative isolates with a positive phenotype-based result, 30 (46%), 20 (30%) and 18 (27%) isolates were positive for OXA-48, KPC and MBL enzymes, respectively, as well as the production of 27% of AmpC with porin loss. Tigecycline was the most effective antibiotic that affected 70% of MDR isolates, but high rates of resistance were detected to other tested antimicrobials. Of interest, a high incidence of MDR, XDR and PDR profiles were observed among all carbapenemase-producing isolates. 36% (24/65) of the tested isolates were MDR to 3 to 5 antimicrobial classes. 29% (17/65) of the recovered isolates were XDR to 6 to 7 antimicrobial classes. Alarmingly, 24% (16/65) of isolates displayed PDR to all the tested 8 antimicrobial classes. Genotype assay, including 53 phenotypically confirmed carbapenemase-producing isolates of Gram-negative bacilli, found 51(96%) isolates were harbouring one or more genes. The most common carbapenemase gene was bla NDM 83% (44/53) followed by bla OXA-48 75% (40/53), bla VIM 49% (26/53) and bla IMP 43% (23/53), while the gene bla KPC was least frequent 7% (4/53). 92% (46/51) of isolates were involved in the production of more than one carbapenemase gene. Conclusion This study demonstrated the emergence of carbapenemase-producing Gram-negative pathogens implicated in healthcare-related infections. Accurate identification of carbapenem-resistant bacterial pathogens is essential for patient treatment, as well as the development of appropriate contamination control measures to limit the rapid spread of pathogens. Tigecycline exhibited potent antimicrobial activity against MDR, XDR and PDR-producing strains that establish a threatening alert which indicates the complex therapy of infections caused by these pathogens.

Author(s):  
Surya Sankar ◽  
Thresia . ◽  
Anu Bosewell ◽  
M. Mini

Background: Carbapenems are beta-lactam antibiotics that are considered as the last line of therapy against multidrug resistant extended spectrum beta-lactamase. The resistance to carbapenems predominantly through carbapenemase is one of the most important emerging health problems worldwide in the therapy of clinical infections. The objective of the present study is to determine the presence of carbapenemase encoding genes among Gram- negative bacterial spp. associated with clinical infections in dogs. Methods: 30 Escherichia coli, 11 Klebsiella pneumoniae and three Pseudomonas aeruginosa isolated from urine, swabs from lesional skin and anterior vagina of dogs presented with different clinical ailments formed the samples for the study. Polymerase chain reaction was carried out to detect the presence of carbapenemase encoding genes viz., KPC, NDM, OXA, VIM and IMP among the isolates.Result: Out of the 44 Gram- negative isolates tested, 28 (76.3%) were positive for at least one tested carbapenemase gene. The highest frequency of carbapenemase recorded was for NDM followed by OXA-181, KPC, OXA-48 and VIM. Our study identified a high prevalence of carbapenemases among companion animals like dogs which could act as potential source of transmission of these resistance bacteria or their genomes to humans.


Author(s):  
Hari P. Nepal ◽  
Rama Paudel

Carbapenems are beta-lactam drugs that have broadest spectrum of activity. They are commonly used as the drugs of last resort to treat complicated bacterial infections. They bind to penicillin binding proteins (PBPs) and inhibit cell wall synthesis in bacteria. Important members that are in clinical use include doripenem, ertapenem, imipenem, and meropenem. Unlike other members, imipenem is hydrolyzed significantly by renal dehydropeptidase; therefore, it is administered together with an inhibitor of renal dehydropeptidase, cilastatin. Carbapenems are usually administered intravenously due to their low oral bioavailability. Most common side effects of these drugs include nausea, vomiting, diarrhea, skin rashes, and reactions at the infusion sites. Increasing resistance to these antibiotics is being reported throughout the world and is posing a threat to public health.  Primary mechanisms of carbapenem resistance include expulsion of drug and inactivation of the drug by production of carbapenemases which may not only hydrolyze carbapenem, but also cephalosporin, penicillin, and aztreonam. Resistance especially among Gram negative bacteria is of much concern since there are only limited therapeutic options available for infections caused by carbapenem resistant Gram-negative bacterial pathogens. Commonly used drugs to treat such infections include polymyxins, fosfomycin and tigecycline.


Author(s):  
Fred C. Tenover

Infections caused by multidrug-resistant Gram-negative organisms have become a global threat. Such infections can be very difficult to treat, especially when they are caused by carbapenemase-producing organisms (CPO). Since infections caused by CPO tend to have worse outcomes than non-CPO infections, it is important to identify the type of carbapenemase present in the isolate or at least the Ambler Class (i.e., A, B, or D), to optimize therapy. Many of the newer beta-lactam/beta-lactamase inhibitor combinations are not active against organisms carrying Class B metallo-enzymes, so differentiating organisms with Class A or D carbapenemases from those with Class B enzymes rapidly is critical. Using molecular tests to detect and differentiate carbapenem-resistance genes (CRG) in bacterial isolates provides fast and actionable results, but utilization of these tests globally appears to be low. Detecting CRG directly in positive blood culture bottles or in syndromic panels coupled with bacterial identification are helpful when results are positive, however, even negative results can provide guidance for anti-infective therapy for key organism-drug combinations when linked to local epidemiology. This perspective will focus on the reluctance of laboratories to use molecular tests as aids to developing therapeutic strategies for infections caused by carbapenem-resistant organisms and how to overcome that reluctance.


2017 ◽  
Vol 66 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Fevronia Kolonitsiou ◽  
Matthaios Papadimitriou-Olivgeris ◽  
Anastasia Spiliopoulou ◽  
Vasiliki Stamouli ◽  
Vasileios Papakostas ◽  
...  

The aim of the study was to assess the epidemiology, the incidence of multidrug-resistant bacteria and bloodstream infections’ (BSIs) seasonality in a university hospital. This retrospective study was carried out in the University General Hospital of Patras, Greece, during 2011–13 y. Blood cultures from patients with clinical presentation suggestive of bloodstream infection were performed by the BacT/ALERT System. Isolates were identified by Vitek 2 Advanced Expert System. Antibiotic susceptibility testing was performed by the disk diffusion method and E-test. Resistance genes (mecA in staphylococci; vanA/vanB/vanC in enterococci; blaKPC/blaVIM/blaNDM in Klebsiella spp.) were detected by PCR. In total, 4607 (9.7%) blood cultures were positive from 47451 sets sent to Department of Microbiology, representing 1732 BSIs. Gram-negative bacteria (52.3%) were the most commonly isolated, followed by Gram-positive (39.5%), fungi (6.6%) and anaerobes bacteria (1.8%). The highest contamination rate was observed among Gram-positive bacteria (42.3%). Among 330 CNS and 150 Staphylococcus aureus, 281 (85.2%) and 60 (40.0%) were mecA-positive, respectively. From 113 enterococci, eight were vanA, two vanB and two vanC-positives. Of the total 207 carbapenem-resistant Klebsiella pneumoniae (73.4%), 202 carried blaKPC, four blaKPC and blaVIM and one blaVIM. A significant increase in monthly BSIs’ incidence was shown (R2: 0.449), which may be attributed to a rise of Gram-positive BSIs (R2: 0.337). Gram-positive BSIs were less frequent in spring (P < 0.001), summer (P < 0.001), and autumn (P < 0.001), as compared to winter months, while Gram-negative bacteria (P < 0.001) and fungi (P < 0.001) were more frequent in summer months. BSIs due to methicillin resistant S. aureus and carbapenem-resistant Gram-negative bacteria increased during the study period. The increasing incidence of BSIs can be attributed to an increase of Gram-positive BSI incidence, even though Gram-negative bacteria remained the predominant ones. Seasonality may play a role in the predominance of Gram-negative’s BSI.


2021 ◽  
Vol 10 (14) ◽  
pp. 1039-1041
Author(s):  
Swathi Gurajala ◽  
Sandeep Kumar Tipparthi ◽  
Rajkumar H.R.V.

Bacteria develop antimicrobial drug resistance through several mechanisms, the common one being the production of enzymes. As the number of antibiotics discovered is in notable numbers in the past few years, it is important to preserve high-end antibiotics for the treatment of multidrug-resistant organisms (MDROs) infections, by appropriate use of antibiotics. A study was conducted to record prevalence, phenotypic and genotypic characters of MDROs in our hospital, with reference to carbapenem resistance. 200 multidrug-resistant clinical isolates were collected in 6 months. Carbapenem-resistant organisms were detected phenotypically confirmed for the production of carbapenemases by modified Hodge test (MHT) and genotypic detection was done by a multiplex polymerase chain reaction (PCR) assay for the five most predominant carbapenemases (bla NDM-1, bla OXA-48 , bla VIM, bla IMP, bla KPC). The isolates consisted of E. coli (53 %) followed by K. pneumoniae (30 %), P. aeruginosa (13 %), and acinetobacter spp (4 %). Among these, 40 (20 %) isolates were carbapenem-resistant. Of these 40, 27 (67.5 %) showed an increase in zone size by the MHT, suggestive of metallo-beta-lactamase (MBL) mediated carbapenem resistance and about 32 (80 %) isolates were found to contain at least one carbapenemase gene. bla NDM-1 accounted for 37.5 % (12 / 32) of the isolates and was the most predominant one followed by bla OXA-48 [28 % (9 / 32)]. 22 % (7 / 32) of the isolates had one or more carbapenemase genes. Identifying the mechanisms of resistance of pathogens is important to implement strict infection prevention and control measures in the hospital to prevent the transmission of the resistant pathogens. KEY WORDS Multidrug-Resistant Bacteria, Bla NDM-1 Gene, Bla OXA-48 Gene, Carbapenem Resistance, Carbapenem Resistant Organisms.


2020 ◽  
Vol 14 (3) ◽  
pp. 2027-2032
Author(s):  
Mita D. Wadekar ◽  
J.V. Sathish ◽  
C. Pooja ◽  
S. Jayashree

Resistance to beta lactam antibiotics is the most common cause for beta-lactamase production. Increasing number of extended spectrum beta-lactamase (ESBL) producers has reduced the treatment options which resulted in emergence of multidrug resistant strains, treatment failure and hence increased mortality. To detect phenotypically, ESBL producers in Gram negative isolates from different samples and to know their susceptibility pattern. A retrospective study of Gram negative isolates was conducted. Total of 521 isolates were isolated from various samples. They were processed and identified by standard procedures. The antibiotic susceptibility testing was performed by Kirby- Bauer disc diffusion method using CLSI guidelines. ESBL was detected by combination disk test. A total of 521 Gram negative isolates were isolated which included E. coli, Klebsiella pneumoniae, Citrobacter spp., Enterobacter spp., Proteus spp. and Acinetobacter spp. Pseudomonas aeruginosa. Of 521 isolates tested, ESBL was detected in 329 (63.1%) isolates. These isolates showed maximum susceptibility to piperacillin- tazobactam (86%) followed by imipenem (78.4%), amikacin (63.5%), cotrimoxazole (54.4%), ciprofloxacin (51%), amoxi-clav (44.9%), cefepime (44.1%), gentamicin (38.9%), cefoxitin (34.9%) and ampicillin (19.1%). ESBL producers which are resistant to beta lactam antibiotics have become a major problem. Detection of these beta-lactamase enzymes by simple disk method and its reporting will help clinicians in prescribing proper antibiotics.


Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 657 ◽  
Author(s):  
Magdalena Plotka ◽  
Malgorzata Kapusta ◽  
Sebastian Dorawa ◽  
Anna-Karina Kaczorowska ◽  
Tadeusz Kaczorowski

Bacteria that thrive in extreme conditions and the bacteriophages that infect them are sources of valuable enzymes resistant to denaturation at high temperatures. Many of these heat-stable proteins are useful for biotechnological applications; nevertheless, none have been utilized as antibacterial agents. Here, we demonstrate the bactericidal potential of Ts2631 endolysin from the extremophilic bacteriophage vB_Tsc2631, which infects Thermus scotoductus, against the alarming multidrug-resistant clinical strains of Acinetobacter baumannii, Pseudomonas aeruginosa and pathogens from the Enterobacteriaceae family. A 2–3.7 log reduction in the bacterial load was observed in antibacterial tests against A. baumannii and P. aeruginosa after 1.5 h. The Ts2631 activity was further enhanced by ethylenediaminetetraacetic acid (EDTA), a metal ion chelator (4.2 log reduction in carbapenem-resistant A. baumannii) and, to a lesser extent, by malic acid and citric acid (2.9 and 3.3 log reductions, respectively). The EDTA/Ts2631 combination reduced all pathogens of the Enterobacteriaceae family, particularly multidrug-resistant Citrobacter braakii, to levels below the detection limit (>6 log); these results indicate that Ts2631 endolysin could be useful to combat Gram-negative pathogens. The investigation of A. baumannii cells treated with Ts2631 endolysin variants under transmission electron and fluorescence microscopy demonstrates that the intrinsic antibacterial activity of Ts2631 endolysin is dependent on the presence of its N-terminal tail.


2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Rémy A. Bonnin ◽  
Agnès B. Jousset ◽  
Lauraine Gauthier ◽  
Cécile Emeraud ◽  
Delphine Girlich ◽  
...  

ABSTRACT A carbapenem-resistant Citrobacter sp. was recovered from routine screening of multidrug-resistant bacteria. This isolate coproduced OXA-48 and OXA-198. OXA-48 was carried by the prototypical IncL plasmid, whereas OXA-198 was carried by a peculiar IncHI-type plasmid. This carbapenemase gene was inserted within a class 1 integron located on a conjugative plasmid. This report describes the first occurrence of OXA-198 in Enterobacterales.


2020 ◽  
Author(s):  
Prasanth Manohar ◽  
Aemy Joseph ◽  
B Karthika ◽  
Pradeep AnuPriya ◽  
Swetha S Mani ◽  
...  

AbstractThe distribution of carbapenem-resistant Gram-negative bacteria has become an increasing public health concern in India. The aim of this study was to investigate the prevalence of carbapenem-resistant bacteria isolated from the clinical samples in Tamil Nadu, India. A total of 126 non-repetitive Gram-negative bacteria were taken for this study. The susceptibility to meropenem was determined by Minimum Inhibitory Concentration (MIC) by broth micro-dilution. The phenotypic resistance screening such as MHT (Modified Hodge test), EDTA disk synergy and CIM (carbapenem inactivation method) were performed. A multiplex PCR was used for the detection of carbapenemase-encoding genes. Among the 126 isolates studied, 82 (65.07%) meropenem-resistant isolates were identified by MIC. A total of 18 (21.9%) isolates were found to be positive for Metallo-β-Lactamase production through EDTA synergy test. None of the isolates were carbapenemase producer by MHT and CIM. The isolates identified with resistance genes (8/82) were blaNDM-1 in two Klebsiella sp., two P. aeruginosa and one A. baumannii, blaVIM-1 in one P. aeruginosa and blaAIM-1 in one P. aeruginosa and one A. baumannii. The study showed the distribution and increase of carbapenem-resistant bacteria in the study region. Therefore, constant monitoring and effective elimination should be focused to reduce the spread of carbapenem-resistant isolates.


10.3823/824 ◽  
2018 ◽  
Vol 8 (3) ◽  
Author(s):  
Abdelraouf A Elmanama ◽  
Mariam Raed Al-Reefi ◽  
Mohammed A. Albayoumi ◽  
Alaa M. Marouf ◽  
Islam F. Hassona

Background: Multidrug resistant bacteria (MDR), such as Escherichia coli and Salmonella spp. are threat to the human health care system. In recent years, these MDR bacteria have been found increasingly inside and outside the hospital environment. Food animals (meat and poultry) are increasingly colonized with MDR bacteria, thus posing an additional concern. This study is intended to determine susceptibility and resistance pattern of pathogenic Gram negative bacteria isolated from rectal swabs of chicken against 16 antibiotics. Methods: A total of 216 cloacal swab samples (Gaza strip poultry farms) and 87 frozen and fresh meat samples (from slaughter houses and retails) from June 2017 to June 2018 were collected. Isolation and identification of organisms were achieved using standard bacteriological techniques. Antimicrobial susceptibility test was performed according to standard protocols. Results: 360 Enterobacteriaceae isolates, and 56 Gram-negative non fermenter were recovered. The predominant Enterobacteriaceae isolate was Citrobacter spp. (22.6%), followed by Enterobacter spp. (17.6%) and E. coli (16.5%). High rates of resistance against Ampicillin (85.4%) and Trimethoprim/ Sulfamethoxazole (80.1%) followed by Chloramphenicol (74%) were recorded. Six samples were positive for Salmonella spp. and Shigella spp. Of the tested Enterobacteriacae isolates, 94.7% were multidrug resistant (MDR), and 31.4% of  None fermenting bacilli (NFB) were MDR. Carbapenem resistance was found to be high among isolates; 51.9% for imipenem and 1.8% for meropenem. Conclusion: Isolated bacteria in the study area were MDR and this suggests that chickens may be important reservoir of antimicrobial resistant organisms which is a major public health concern.    


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