Pan-drug Resistance Research Articles

Analysis of diverse β-lactamases presenting high-level resistance in association with OmpK35 and OmpK36 porins in ESBL-producing Klebsiella pneumoniae

Emerging extensively drug-resistant (XDR) Klebsiella pneumoniae due to the production of β-lactamases and porin loss is a substantial worldwide concern. This study aimed to elucidate the role of outer membrane porin (OMP) loss, AmpC, and carbapenemases among extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae strains with XDR phenotype. This study analyzed 79 K. pneumoniae from several clinical sources and detected ESBLs in 29 strains co-harbored with other β-lactamases using standard microbiological practices and phenotypic procedures. Minimum inhibitory concentrations (MICs) were determined against several antibiotics using Microscan WalkAway plus. OMP analysis was carried out using sodium dodecyl sulfate–polyacrylamide gel electrophoresis. ESBL, AmpC, and carbapenemase genes were detected using molecular methods. The microbiological analysis discovered 29 (36.7%) ESBL strains of K. pneumoniae, which showed the co-existence of 7 (24.1%) AmpC β-lactamases and 22 (75.9%) carbapenemases. Porin loss of OmpK35 was observed in 13 (44.8%) and OmpK36 in 8 (27.5%) K. pneumoniae strains. The strains were significantly associated with the intensive care unit (ICU) (p = 0.006) and urinary sources (p = 0.004). The most commonly detected gene variants in each β-lactamase class included 16 (55.2%) blaCTX-M−1, 7 (100%) blaCYM-2, 11 (50%) blaNDM-1, and integron-1 was detected in 21/29 (72.4%) strains. MICs of cephalosporin, fluoroquinolone, carbapenem, aminoglycoside, and β-lactam combinations demonstrated a high number of XDR strains. Tigecycline (2 µg/mL MIC50 and >32 µg/mL MIC90) and colistin (1 µg/mL MIC50 and 8 µg/mL MIC90) presented lower resistance. ESBL K. pneumoniae strains with OmpK35 and OmpK36 porin loss demonstrate conglomerate resistance mechanisms with AmpC and carbapenemases, leading to emerging XDR and pan drug resistance.

Evaluation of microbial infections of ear and their susceptibility pattern in a tertiary care hospital

Nearly 0.065-0.33 billion people suffer from ear infections leading to loss of hearing in 60% of them. As the middle ear is in close proximity to the brain, infections can lead to intracranial complications. Inappropriate use of antibiotics in these situations can lead to multi drug resistant bacterial strains. Hence, the knowledge of commonest bacteria causing these infections along with its susceptibility pattern remains a key to unravel the void left in otological microbiome.: Aretrospective analysis of samples obtained from middle ear infections were analyzed for a period of 4 months (2019) at the Department of Microbiology, SRIHER using Hospital information system. The results of microbiological profile and their susceptibility pattern were tabulated and statistically analyzed.: Out of 325 samples enrolled, 302 samples grew pathogens(GPC:122,GNB:186, Fungi:17 & 23 of them grew more than 1 pathogen). The microbiological profile of 325 pathogens were: Pseudomonas aeruginosa 41.8%, Staphylococcus aureus 27.6%, CONS 7.6%, Klebsiella pneumoniae 4.6%, Proteus species 4.6%,Candida species 3.3%, Streptococcus species 2.2%,Escherichia coli 1.8%, Aspergillus species 1.8%, Acinetobacter species 1.2%, Enterobacter species 1.2%, Citrobacter species 0.9%, Morganella species 0.6%, Providencia species 0.3%. Multi-drug-resistant strains were seen in 17 of GNB 9.1%(n=186), predominantly in Pseudomonas species 8.8%(n=136). Methicillin resistance among the Staphylococcus species was 22%(n=115), predominantly in CONS 64%(n=25). Pan-drug resistance was not reported.Based on our study, a total of 43(13.2%) isolates were MDR strains, hence it is imperative to do a culture and sensitivity pattern of ear infections for efficacious management, thereby reducing further complications.

Antibiotic Resistance Pattern Of Acinetobacter Baumannii Isolated From Bacteremia Patients In Pakistan.

Acinetobacter baumannii causes a number of life-threatening infections in Hospitalized patients attributed to its ability to develop resistance against multiple antibiotics. The current scrutinisation is aimed to observe the prevalence and antibiotic resistance profile of A. baumannii strains isolated from blood of tertiary care Hospitalized patients in Lahore, Pakistan. This research is a retrospective study conducted over a period of one year where 1864 blood samples were collected from both male and female patients with septicaemia. Total 156 A. baumannii species were identified by conventional method and their antimicrobial resistance pattern against 22 antimicrobials (representing all known classes of antibiotics) was evaluated by Kirby Bauer disc diffusion method. MICs of colistin, polymyxin B and vancomycin against A. baumannii were calculated by E test and broth dilution method. More males (n=97, 62%) were found infected than females (n=59, 38%). The spreading rate of A. baumannii was highest (n=101, 65%) in patients of age ≤20 years, and lowest (n=12, 7%) in the patients with the age of 41-60 years. Most of the strains of A. baumannii (n=118, 75.6%) were found to be MDR (multi drug resistant), 37 (23.7%) strains were XDR (Extensively drug-resistant) and only 1 (0.05%) strain was PDR (pandrug resistant). All the strains were sensitive to minocycline and tigecycline whereas highest non-susceptibility (n=144, 92%) was seen against Ampicillin-Sulbactam. Most of the strains demonstrated resistance against carbapenem and cephalosporin beckoning that A. baumannii can no longer be considered for salvage therapy by carbapenem. MICs of colistin, polymyxin B and vancomycin against A. baumannii divulged polymixin B as the most effective drug. Use of wide range of drugs has made A. baumannii multidrug resistant. Colistin, polymyxin B and vancomycin are the preferable drugs for the treatment of A. baumannii infections.

Assessment of In-Vitro Synergy of Fosfomycin with Meropenem, Amikacin and Tigecycline in Whole Genome Sequenced Extended and Pan Drug Resistant Klebsiella Pneumoniae: Exploring A Colistin Sparing Protocol.

Fosfomycin has emerged as a very useful antimicrobial in management of extremely drug resistant (XDR) and pan drug resistant (PDR) Klebsiella pneumoniae. In this study, we assessed in-vitro synergy of colistin sparing combinations of fosfomycin (FOS) with meropenem (MEM), tigecycline (TGC) and amikacin (AK) against XDR and PDR Klebsiella pneumoniae. Method: Non-replicate fully characterised 18 clinical isolates of K. pneumoniae (15 XDR and 3 PDR strains) were subjected to in-vitro synergy testing by checkerboard and time kill assay. Combinations tested were FOS-MEM, FOS-TGC and FOS-AK with glucose-6-phosphate being incorporated in all runs.WGS was carried out on the Illumina next-generation sequencing platform. Results: FOS-MEM and FOS-AK both demonstrated excellent synergy against all PDRs and all but one XDR. Synergy led to lowering of MICs to susceptible breakpoints. FOS-TGC demonstrated antagonism. MLST-231 K. pneumoniae predominated (14), followed by ST-395 (3) and ST147 (1). Majority harboured OXA-232 (n = 15), while n = 2 carried NDM-1 type and n = 1 co-carried NDM-5 + OXA-232. Mortality was high in both ST-231 (57.1%) and ST-395 (66.6%). Synergy was observed despite widespread presence of resistance markers against aminoglycosides [aph(3′)-Ic, aacA4, and rmtf], beta-lactams [blaSHV-11, blaTEM-1b, blaCTX-M-15, and blaOXA-232], fosfomycin [fosA6 and fosA5] and presence of porin proteins OmpK37, OmpA and K. pneumoniae antibiotic efflux pumps Kpn F, H, G, and E. Conclusion: FOS + MEM and FOS + AK are excellent colistin sparing combinations against ST 231, ST-395 and ST-147 XDR and PDR K. pneumoniae. FOS with fewer side effects than colistin, excellent tissue distribution and minimal side effects may be recommended in combination with meropenem.

RETRACTED ARTICLE: Antimicrobial and anti-biofilm potencies of dermcidin-derived peptide DCD-1L against Acinetobacter baumannii: an in vivo wound healing model

BackgroundThe global emergence of Acinetobacter baumannii resistance to most conventional antibiotics presents a major therapeutic challenge and necessitates the discovery of new antibacterial agents. The purpose of this study was to investigate in vitro and in vivo anti-biofilm potency of dermcidin-1L (DCD-1L) against extensively drug-resistant (XDR)-, pandrug-resistant (PDR)-, and ATCC19606-A. baumannii.MethodsAfter determination of minimum inhibitory concentration (MIC) of DCD-1L, in vitro anti-adhesive and anti-biofilm activities of DCD-1L were evaluated. Cytotoxicity, hemolytic activity, and the effect of DCD-1L treatment on the expression of various biofilm-associated genes were determined. The inhibitory effect of DCD-1L on biofilm formation in the model of catheter-associated infection, as well as, histopathological examination of the burn wound sites of mice treated with DCD-1L were assessed.ResultsThe bacterial adhesion and biofilm formation in all A. baumannii isolates were inhibited at 2 × , 4 × , and 8 × MIC of DCD-1L, while only 8 × MIC of DCD-1L was able to destroy the pre-formed biofilm in vitro. Also, reduce the expression of genes involved in biofilm formation was observed following DCD-1L treatment. DCD-1L without cytotoxic and hemolytic activities significantly reduced the biofilm formation in the model of catheter-associated infection. In vivo results showed that the count of A. baumannii in infected wounds was significantly decreased and the promotion in wound healing by the acceleration of skin re-epithelialization in mice was observed following treatment with 8 × MIC of DCD-1L.ConclusionsResults of this study demonstrated that DCD-1L can inhibit bacterial attachment and biofilm formation and prevent the onset of infection. Taking these properties together, DCD-1L appears as a promising candidate for antimicrobial and anti-biofilm drug development.

Prevalence of multidrug-resistant, extensively drug-resistant, and pandrug-resistant phenotypes among Klebsiella pneumoniae collected from referral therapeutic centers in Sari, North Iran

Aims: Klebsiella pneumoniae is an important cause of nosocomial infections. The present study sought to detect resistance status and the frequency of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) K. pneumoniae strains isolated from hospitalized patients. Materials and Methods: Confirmation of K. pneumoniae isolates was performed by polymerase chain reaction (PCR) for rpoB fragment. Drug susceptibility was done by disk diffusion method based on the Clinical and Laboratory Standards Institute. According to the susceptibility pattern, the strains were categorized as MDR, XDR, and PDR. Results: On the basis of PCR results, rpoB gene was identified in all 100 K. pneumoniae isolates. Most K. pneumoniae strains showed a high percentage of resistance against ampicillin-sulbactam (93%). On the other hand, tigecycline and fosfomycin were active against 100% and 90% isolates, respectively. The multiple resistance analysis of the strains showed that 58% and 13% of isolates were identified as MDR and XDR, respectively. Overall, no PDR isolate was detected in any tested strains. Conclusion: Our results demonstrated that the vast majority of K. pneumoniae strains indicated the MDR phenotype including a high resistance rate to common antibiotics. Therefore, it is suggested to implement antimicrobial susceptibility testing before prescribing, to assist in selecting the most effective agents within the antimicrobial categories for the treatment of infections with multiple antibiotic-resistant K. pneumoniae strains in hospitalized patients.

Investigation of ceftazidime-avibactam susceptibility in clinical isolates of gram-negative bacteria.

Our study investigated the susceptibility rate of ceftazidime-avibactam and the risk factors associated with its resistance by analyzing gram-negative bacteria isolated from various patient samples. Between March and November 2020, 1119 gram-negative bacteria strains were isolated from patient samples in Acıbadem Healthcare Group hospitals; ceftazidime-avibactam susceptibility results were evaluated using a 10/4µg (Oxoid, UK) disc and evaluated according to Eucast 2020 recommendations. Patient and isolate characteristics that could be risk factors were retrospectively investigated and statistically analyzed using SPSS 25.0. Male patients made up 52% (n = 581) of the study's total patient population, and they averaged 55.5 ± 24.9 years old. Of 1119 gram-negative strains culture and antibiogram, 1023 (91.4%) were sensitive to ceftazidime-avibactam. An increased risk of resistance was observed with female gender (OR = 2.29; CI 95% [1.45-3.61]; p < 0.05), Pseudomonas aeruginosa (OR = 1.67, CI 95% [1.03-2.7]; p < 0.05), the presence of multidrug-resistance (MDR) (OR = 4.07, CI 95% [2.47-6.7]; p < 0.05) pandrug-resistance (PDR) (OR = 12, (CI) 95% [9.9-14.7] ]; p < 0.05) and admission to intensive care unit (ICU) (OR = 1.89, CI 95% [1.22-2.93]; p < 0.05). The resistance rate of ceftazidime-avibactam was found to be 8.6%, and it was thought that resistant strains produced metallo-ß-lactamase (MBL) type carbapenemase. Risk factors were female gender, Pseudomonas aeruginosa, MDR, PDR, and admission to ICU. Therefore, studying the ceftazidime-avibactam susceptibility test together with gram-negative bacteria identification, especially in groups at risk for resistance, is one of the important factors that can positively affect the success of treatment.

Evaluating the Activity of Ultrasound on Biofilm Formation by Acinetobacter baumannii isolated from clinical Specimens

Acinetobacter baumannii received attention for its multi-drug resistant associated with many severe infections and outbreaks in clinical environment. The aims of the study are to investigate the antibiotic susceptibility profile of clinically isolated A. baumannii, biofilm production, and the efficiency of Low Frequency Ultrasound (LFU) and honey to attenuate biofilm production. A total of 100 samples were taken from different sources from Baghdad hospitals. The susceptibility patterns revealed the percentage of pan drug resistant (PDR) isolates were 1.5 %, 72.7 % were extended drug resistant (XDR), 16.7 % were multidrug resistant (MDR), and 9.1 % were non MDR and sensitive to most antibiotics used. The ability to form biofilm was detected by crystal violet staining, and the results showed that 20% were strong biofilm, and 31.8% were moderate biofilm. The biofilm formation percentage was decreased using Low frequency ultrasound LFU and honey. Moreover, PCR results revealed that not all of them harbouring biofilm-related genes or integrons (bap, csuE, IntI-1, IntI-2), although, they are strong biofilm producers. These results conclude that low frequency ultrasound and chemical components of honey might be a good choice to restrain A. baumannii biofilm formation, and negative correlation between antibiotic resistance and biofilm ability. Running title: Antimicrobial drug resistance, Acinetobacter baumannii, biofilm inhibition

Retrospective Analysis of Bacterial Isolates during Blood Stream Infections in Children with Chemotherapy-induced Febrile Neutropenia: A Single Centre Experience

Abstract Introduction The recent advances in cancer treatment have resulted in significant improvement in the outcome of pediatric cancers. However, febrile neutropenia (FN) is the most important cause of mortality and morbidity in pediatric cancer patients and is a crucial limiting factor for the outcome. The greatest threat that we are facing is the emergence of pan drug-resistant (PDR) organisms. Objectives To study bacterial organisms causing bloodstream infections (BSI) during febrile neutropenia episodes, their antibiotic sensitivity pattern, impact on treatment outcome during the intensive phase of chemotherapy, and the association between prior administration of antibiotics and emergence of multidrug-resistant organisms (MDR). Materials and Methods This retrospective study was conducted in patients between the age group of 0 to 18 years who were treated for malignancies in the division of pediatric oncology at a tertiary center from August 2017 to December 2020. Blood cultures were collected under aseptic precautions, and they were processed as per the Clinical and Laboratory Standard Institute Guideline (CLSI) 2017. Results A total of 122/159 (76.7%) patients were diagnosed to have hematological malignancies, and 37/159 (23.3%) patients were found to be suffering from solid tumors. A total of 309 episodes of FN were documented and 386 cultures were sent, out of which 87/386 (22.53%) cultures were positive for bacteria and 2/386 (2.2%) for fungi. Gram-negative isolates were seen in 51/87 (58.62%) cultures and Gram-positive in 36/87 (41.37%) cultures. Burkholderia cepacia and coagulase-negative Staphylococci (CONS) were the commonest found Gram-negative and Gram-positive bacteria, respectively. MDR bacterial strains were seen in 44/87 (50.57%) cultures and PDR strains in 8/87 (9.2%) cultures. Resistance was higher with Klebsiella species and CONS. There were six mortalities during the induction phase of acute leukemia treatment, out of which 4/6 (66.66%) were due to MDR infections, 1/6 (16.6%) due to fungal infection and chemotherapy refractoriness each. Conclusion Proven bacterial infections were determined in 22.53% of febrile neutropenia episodes. Most BSI in patients with febrile neutropenia were caused by Gram-negative bacteria. Indiscriminate use of higher antibiotics before referral led to the emergence of MDR organisms, thus compromising the outcome. Our study emphasizes the fact that antibiotic stewardship is a crucial task to counter MDR bacteremia-related morbidity and mortality in neutropenic children.

Detection of synergistic antimicrobial resistance mechanisms in clinical isolates of Pseudomonas aeruginosa from post-operative wound infections.

Infections caused by carbapenem-resistant Pseudomonas aeruginosa are life-threatening due to its synergistic resistance mechanisms resulting in the ineffectiveness of the used antimicrobials. This study aimed to characterize P. aeruginosa isolates for antimicrobial susceptibility, biofilm formation virulence genes, and molecular mechanisms responsible for resistance against various antimicrobials. Out of 700 samples, 91 isolates were confirmed as P. aeruginosa which were further classified into 19 non-multidrug-resistant (non-MDR), 7 multidrug-resistant (MDR), 19 extensively drug-resistant (XDR), and 8 pan drug-resistant (PDR) pulsotypes based on standard Kirby Bauer disc diffusion test and pulse field gel electrophoresis. In M9 minimal media, strong biofilms were formed by the XDR and PDR pulsotypes as compared to the non-MDR pulsotypes. The virulence genes, responsible for the worsening of wounds including LasB, plcH, toxA, and exoU, were detected among all MDR, XDR, and PDR pulsotypes. Carbapenemase activity was phenotypically detected in 45% pulsotypes and the responsible genes were found as blaGES (100%), blaVIM (58%), blaIMP (4%), and blaNDM (4%). Real-time polymerase chain reaction showed the concomitant use of multiple mechanisms such as oprD under-expression, enhanced efflux pump activity, and ampC overexpression in the resistant isolates. Polymyxin is found as the only class left with more than 80% susceptibility among the isolates which is an alarming situation suggesting appropriate measures to be taken including alternative therapies. KEY POINTS: • Multidrug-resistant P. aeruginosa isolates formed stronger biofilms in minimal media. • Only polymyxin antimicrobial was found effective against MDR P. aeruginosa isolates. • Under-expression of oprD and overexpression of ampC were found in resistant isolates.

Molecular Detection of Fluoroquinolone Resistance among Multidrug-, Extensively Drug-, and Pan-Drug-Resistant Campylobacter Species in Egypt.

In recent times, resistant foodborne pathogens, especially of the Campylobacter species, have created several global crises. These crises have been compounded due to the evolution of multidrug-resistant (MDR) bacterial pathogens and the emergence of extensively drug-resistant (XDR) and pan-drug-resistant (PDR) strains. Therefore, this study aimed to investigate the development of resistance and the existence of both XDR and PDR among Campylobacter isolates. Moreover, we explored the use of the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) technique for the detection of fluoroquinolone (FQ)-resistant Campylobacter isolates. A total of 120 Campylobacter isolates were identified depending on both phenotypic and genotypic methods. Of note, cefoxitin and imipenem were the most effective drugs against the investigated Campylobacter isolates. Interestingly, the majority of our isolates (75%) were MDR. Unfortunately, both XDR and PDR isolates were detected in our study with prevalence rates of 20.8% and 4.2%, respectively. All FQ-resistant isolates with ciprofloxacin minimum inhibitory concentrations ≥4 µg/mL were confirmed by the genetic detection of gyrA chromosomal mutation via substitution of threonine at position 86 to isoleucine (Thr-86-to-Ile) using the PCR-RFLP technique. Herein, PCR-RFLP was a more practical and less expensive method used for the detection of FQ resistant isolates. In conclusion, we introduced a fast genetic method for the identification of FQ-resistant isolates to avoid treatment failure through the proper description of antimicrobials.

Characteristics of Carbapenem-Resistant Gram-Negative Bacilli in Patients with Ventilator-Associated Pneumonia.

Carbapenem-resistant Gram-negative bacilli (CR-GNB) has become a global threat. In hospital settings, the association of CR-GNB with ventilator-associated pneumonia (VAP) is a critical public health concern owing to their high resistance rate to most antibiotics. The present study aims to identify the frequency of carbapenem-resistance and to determine the rate of multidrug resistance (MDR), extensive drug resistance (XDR) and pan-drug resistance (PDR) among CR-GNB infections in VAP. Antimicrobial susceptibility testing was carried out using the disk diffusion method and the detection of carbapenemases was screened using the imipenem-E test and the modified carbapenem-inactivation method (mCIM). The isolates were verified by polymerase chain reaction (PCR) for the presence of blaNDM, blaSPM, blaVIM, blaIMP and blaGIM genes. 89.5%, 14%, 17.5%, 10.5%, 3.5% of isolates exhibited the presence of blaNDM, blaVIM, blaSPM, blaIMP and blaGIM, respectively. 76%, 17% and 7% of isolates were PDR, XDR, and MDR, respectively. Carbapenem-resistance genes were identified in a significant percentage and blaNDM was the most predominant gene. All isolates were highly resistant to most antibiotics. This health concern has proven to be a big challenge in developing countries such as Egypt, as it is associated with high morbidity, high mortality, and raised healthcare costs.

Resistance Patterns of Gram-Negative Bacteria Recovered from Clinical Specimens of Intensive Care Patients.

Intensive care units are complex environments favoring high resistance in microorganisms. This study evaluated the resistance and the distribution dynamics of resistant Gram-negative bacteria (GNB) in patients admitted to intensive care units. This retrospective, record-based, cross-sectional study analyzed all of the antibiograms of patients admitted to the ICUs. The BD Phoenix system (BD Diagnostics, Sparks, MD, USA) was used for bacterial identification and antimicrobial testing. Clinical and Laboratory Standard Institute recommendations were used for antimicrobial testing. Frequencies and percentages of multidrug and pan-drug resistance were calculated. A total of 570 bacterial growths were observed, out of which 437 (76.7%) were of GNB. K. pneumoniae (21.0%), P. aeruginosa (11.8%), and Staphylococcus aureus (13.2%) were the most frequent disease-causing bacteria in intensive care patients. Resistance rates of 73.2% and 70.1% were observed for third- and fourth-generation cephalosporins, respectively, while 48.2% carbapenem and > 65% fluoroquinolones resistance rates were observed. Amikacin was the most effective antibiotic, with a sensitivity rate of 69.5%. A total of 372 (85.1%) of GNB were multidrug resistant. The majority of infections in intensive care patients are caused by multidrug-resistant (MDR) Gram-negative bacteria. Female gender and advancing age are factors favoring MDR. Enhanced surveillance and strengthening of the antimicrobial stewardship program are warranted.

Bacteriophage as a Novel Therapeutic Weapon for Killing Colistin-Resistant Multi-Drug-Resistant and Extensively Drug-Resistant Gram-Negative Bacteria.

Colistin-resistant multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) bacteria are highly lethal and many researchers have tried hard to combat these microorganisms around the world. Infections caused by these bacteria are resistant to the last resort of antibiotic therapy and have posed a major challenge in clinical and public health. Since the production of new antibiotics is very expensive and also very slow compared to the increasing rate of antibiotic resistance, researchers are suggesting the use of natural substances with high antibacterial potential. Bacteriophages are one of the most effective therapeutic measures that are known to exist for use for incurable and highly resistant infections. Phages are highly taken into consideration due to the lack of side effects, potential spread to various body organs, distinct modes of action from antibiotics, and proliferation at the site of infection. Although the effects of phages on MDR and XDR bacteria have been demonstrated in various studies, only a few have investigated the effect of phage therapy on colistin-resistant isolates. Therefore, in this review, we discuss the problems caused by colistin-resistant MDR and XDR bacteria in the clinics, explain the different mechanisms associated with colistin resistance, introduce bacteriophage therapy as a powerful remedy, and finally present new studies that have used bacteriophages against colistin-resistant isolates.

High frequency of multidrug-resistant (MDR) Klebsiella pneumoniae harboring several \u03b2-lactamase and integron genes collected from several hospitals in the north of Iran

BackgroundKlebsiella pneumoniae is one of the leading causes of hospital outbreaks worldwide. Also, antibiotic-resistant K. pneumoniae is progressively being involved in invasive infections with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the incidence of resistance genes (integron types and β-lactamase-encoded genes) among clinical isolates of K. pneumoniae.MethodsIn this cross-sectional study, a total of 100 clinical samples were obtained from hospitalized patients in three teaching hospitals in the north of Iran, from November 2018 and October 2019. Antimicrobial susceptibility testing was performed using disk agar diffusion test in line with CLSI recommendations. For colistin, minimum inhibitory concentration (MIC) was determined using broth microdilution. Based on antibiogram, multi-drug resistant (MDR) and extensive-drug resistant (XDR) strains were detected. Finally, integron types and β-lactamase resistance genes were identified using polymerase chain reaction technique.ResultsThe most and least clinical samples were related to the urine and bronchoalveolar lavage, respectively. Based on the antibiogram results, amikacin and gentamicin exhibited good activity against K. pneumoniae strains in vitro. The high resistance rate (93%) to ampicillin/sulbactam predicts the limited efficacy of this antibiotic, in the hospitals studied. Among all the 100 isolates, the frequency of MDR and XDR phenotypes were 58% and 13%, respectively, while no pan-drug resistant (PDR) strains were found. In the MDR K. pneumoniae strains, the prevalence of blaSHV, blaTEM, blaCTX-M-15, blaKPC, blaOXA-48, blaNDM β-lactamase genes were 91.4%, 82.7%, 79.3%, 29.3%, 36.2% and 6.9%, respectively, however 91.4% of the isolates were carrying intI gene. Class II and III integrons were not detected in any isolates.ConclusionThe MDR K. pneumoniae is becoming a serious problem in hospitals, with many strains developing resistance to most available antimicrobials. Our results indicate co-presence of a series of β-lactamase and integron types on the MDR strains recovered from hospitalized patients. The increasing rate of these isolates emphasizes the importance of choosing an appropriate antimicrobial regimen based on antibiotic susceptibility pattern.

Occurrence of Multiple, Extensive and Pan Drug-Resistant Pseudomonas aeruginosa and Carbapenemase Production from Presumptive Isolates Stored in a Biobank at Ethiopian Public Health Institute.

PurposePseudomonas aeruginosa is a common cause of nosocomial infections with associated morbidity and mortality because the organism is unresponsive to commonly available antimicrobials. This study was undertaken to determine the multiple drug-resistant (MDR), extensive drug-resistant (XDR) and pan drug-resistant (PDR) phenotype of P. aeruginosa and its carbapenemase production rate from presumptive isolates stored in the biobank at the Ethiopian Public Health Institute (EPHI).MethodsA cross-sectional study was conducted at the EPHI laboratory, Addis Ababa, Ethiopia from March to June 2021. Stored isolates of Pseudomonas spp. which had been characterized by manual identification methods were further processed for species-level identification (ID) and antimicrobial susceptibility testing (AST) using a Becton Dickinson (BD) Phoenix automated system. The isolates were analyzed for carbapenemase enzyme production using the modified Carbapenem Inactivation Method (mCIM). The data analysis was done using SPSS version 20 software.ResultsIn this study, 110 presumptive Pseudomonas isolates from a biobank were re-analyzed, 100 of them were found to be Pseudomonas and among these P. aeruginosa accounted for 98% and P. putida accounted for 2%. The majority of isolates were recovered from wound (46%) specimens followed by ear swabs (18%). The highest level of resistance was observed against ceftazidime (35%) and the lowest level of resistance was observed against amikacin (2%). Twenty-seven isolates were identified as candidates for carbapenemase enzyme production testing, of which only 3/27 (11%) isolates were detected as carbapenemase enzyme producers.ConclusionThis study shows an increasing rate of MDR and XDR isolates and the appearance of PDR in P. aeruginosa strains; this is a serious problem in Ethiopia. The lack of newer anti-pseudomonal antibiotics adds to the problem. In order to alleviate this, infection prevention activities should be promoted, and treatment of bacterial infections should be guided by antibiotic susceptibility test results.

Antibiotic resistance and biofilm formation of Acinetobacter baumannii isolated from high-risk effluent water in tertiary hospitals in South Africa

Discharge of drug-resistant, biofilm-forming pathogens from hospital effluent water into municipal wastewater treatment plants poses a public health concern. This study examined the relationship between antibiotic resistance levels and biofilm formation of Acinetobacter baumannii strains isolated from hospital effluents. Antibiotic susceptibility of 71 A. baumannii isolates was evaluated by the Kirby-Bauer disk diffusion method. Minimum inhibitory concentrations (MICs) were determined by the agar dilution method, while the minimum biofilm eradication concentration (MBEC) was determined by the broth dilution method. Genotyping was performed for plasmid DNA. Biofilm formation was evaluated by the microtitre plate method and was quantified using crystal violet. A P-value of <0.05 was regarded as statistically significant in all tests. Extensively drug-resistant (XDR) strains made up 58% of the isolates, while multidrug-resistant (MDR) and pandrug-resistant (PDR) strains made up 50% of the isolates from final effluent. The MBEC of ciprofloxacin increased by 255-fold, while that of ceftazidime was as high as 63-1310-fold compared with their respective MICs. Isolates were classified into four plasmid pattern groups with no association between biofilm formation and plasmid type (P=0.0921). The degree of biofilm formation was independent of the level of antibiotic resistance, although MDR, XDR and PDR isolates produced significant biofilm biomass (P=0.2580). These results suggest that hospital effluent is a potential source of MDR biofilm-forming A. baumannii strains. Appropriate treatment and disposal of effluents are essential to prevent the presence of drug-resistant pathogens in wastewater.

English

Antimicrobial surveillance and identifying the genetic basis of antimicrobial resistance provide important information to optimize patient care. The present study is an analytical cross sectional study aimed to determine the prevalence of multidrug resistant (MDR), extensively drug resistant (XDR), pan drug resistant (PDR) and extended-spectrum ?-lactamases genes among Gram-negative bacteria isolated in Saudi Arabia.&nbsp; A total number of 386 non-duplicate Gram-negative isolates were collected. Identification and susceptibility testing were done using automation system (BD Phoenix&trade;). The extracted DNAs were subjected to multiplex polymerase chain reaction (PCR). The results showed that only 15 (3.9%) of isolates were fully susceptible, the overall prevalence of XDR, MDR, PDR was 129 (33.4%), 113 (29.3%) and 48(12.4%) respectively. High resistant rate was observed against the antibiotic agents of cephalosporins class 79.3% followed by the agents of penicillins class 69.4%. The most dominant resistant gene was bla SHV which was detected in 106/386 (27.5%) isolates, followed by bla CTX-M 90/386 (23.3%). Bla CTX-M showed significant relation with all used antibiotic except ampicillin/clavulanic acid, aztreonam, cefoxtin, and meropene. The isolates which showed frequent resistant genes were: Klebsiella pneumoniae 90/124 (72.6%), A. baumanni 37/67 (55.2%), and P. mirabilis 24/44 (54.5%). These findings underscore the need for optimization of current therapies and prevention of the spread of these organisms. &nbsp; Key word: Multidrug resistant (MDR), extensively drug resistant (XDR), pan drug resistant (PDR), extended spectrum beta lactamase (ESBL), bla SHV, bla TEM, bla CTX-M.

Genetyping of Carbapenem-resistant Organisms Isolated from Clinical Isolates Received from Tertiary Care Hospitals of Ahmedabad, Gujarat

The world is seeing a continuous rise in the levels of antibiotic resistance1. Organisms develop new resistance mechanisms, emerge, and spread the resistance worldwide, making it challenging to treat common infectious diseases. In the current study, clinical isolates received between the years 2017 to 2020 were cultured and the isolated organisms were screened for antibiotic resistance; isolates with multiple drug resistance were further subjected to confirmatory screening through Combined Disc Test (CDT) and Modified Hodge Test (M.H.T.), and molecular characterization to be finally tested for gene expression analysis. Molecular characterization involved screening of genes blaVIM-2, blaKPC-3, blaNDM-1, and blaIMP-11 responsible for imparting carbapenem drug resistance2. From the laboratories of tertiary care hospitals, a total of 1452 clinical isolates were collected and identified. The organisms were subjected to antibiotic susceptibility screening and carbapenem resistance screening. The isolates found positive in the screenings were subjected to molecular characterization for genes, blaVIM-2, blaKPC-3, blaNDM-1, and blaIMP-11, responsible for imparting carbapenem drug resistance. Most of the isolates were resistant variably to aminoglycosides but were found to be resistant to fluoroquinolones and β-lactams group of antibiotics. Carbapenem activity was detected in twelve percent of total isolates and 27 percent among multidrug-resistant isolates. blaNDM-1 gene was found present in 77% isolates, and five organisms among the total number of organisms showed pan drug resistance.

Prevalence of common bacterial etiology and antimicrobial susceptibility pattern in patients with otitis media in Duhok Province –Iraq

&nbsp;&nbsp;&nbsp;&nbsp; Otitis media is the most frequent type of ear infection. It is a major health problem for both children and adults but the proportion is different in different countries. The current study was designed to determine the frequency of bacterial isolates causing otitis media and their antimicrobial resistance profile to assess the incidence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan drug resistance (PDR) among the isolated pathogens. Also, to determine the various risk factors (age, gender, type, and site of infection) associated with ear infection. A total of 200 ear discharge samples were collected from patients aged 1-77 years attending the Ear, Nose, and Throat (ENT) unit in Azadi Teaching Hospital in Duhok city from November 2018 to September 2019. The clinical samples were cultured and bacterial isolates were identified by standard microbiological methods then confirmed by VITEK®&nbsp;2 Compact automated system. All gram-negative bacterial isolates were studied phenotypically for Extended Spectrum Beta Lactamase production. Out of 200 ear swabs, 95% confirmed positive culture; 85.8% were bacterial isolates. From the total bacterial isolates, 57% were gram-positive bacteria, while gram-negative bacteria were 43%; with predominant of Pseudomonas aeruginosa, (22%) followed by Staphylococcus aureus (19%) and Coagulase negative Staphylococci (18%). The prevalence of otitis media was not significantly affected by gender. The majority of patients belonged to the age group (1-10) years old. 64.1% of the isolates were characterized as MDR, 31.7% were XDR, with one (0.7%) as PDR. Among these, 60.7% isolates were ESBL producers, Pseudomonas aeruginosa was the most frequent ESBL- producing isolates (45.9%), followed by Proteus spp (18.9%). The in-vitro sensitivity results indicated that Gentamycin and Ciprofloxacin were effective antibiotics in the treatment of otitis media. Additionally, Meropenem, Imipenem, Cefepime, and Azetronam were also the most effective drug against Pseudomonas aeruginosa. We concluded that the drug resistant isolates were common, worryingly high, leaving only limited drugs as a treatment choice.