Beta-lactamase Research Articles

Six-year evaluation of device-associated nosocomial infections in intensive care units.

Invasive device-associated nosocomial infections commonly occur in intensive care units (ICUs). These infections include intravascular catheter-related bloodstream infection (CRBSI), ventilator-associated pneumonia (VAP), and catheter-associated urinary tract infection (CAUTI). This study aimed to evaluate the factors associated with invasive device-associated nosocomial infections based on the underlying diseases of the patients and antibiotic resistance profiles of the pathogens causing the infections detected in the ICU in our hospital over a five-year period. Invasive device-associated infections (CRBSI, VAP, and CAUTI) were detected retrospectively by the laboratory- and clinic-based active surveillance system according to the criteria of the US Centers for Disease Control and Prevention (CDC) in patients hospitalized in the ICU of the tertiary hospital between 1 January 2018 and 30 June 2023. A total of 425 invasive device-associated nosocomial infections and 441 culture results were detected (179 CRBSI, 176 VAP, 70 CAUTI). Out of them, 57 (13.4%) patients had hematological malignancy, 145 (34.1%) had solid organ malignancy, and 223 (52.5%) had no histopathologic diagnosis of any malignancy. An increase in extended-spectrum beta lactamase (ESBL) and carbapenem resistance in pathogens was detected during the study period. Antibiotic resistance of the Gram-negative bacteria associated with invasive device-associated infections increased during the study period. Antimicrobial stewardship will reduce rates of nosocomial infections, reduce mortality, and shorten hospital stay. Long-term catheterization and unnecessary antibiotic use should be avoided.

Prevalence of Multi Drug Resistant Coagulase Negative Staphylococci among some Pregnant Women Attending Antenatal Clinic in Yola, Nigeria

Study’s Novelty/Excerpt This study presents findings on the prevalence and characterization of coagulase-negative staphylococci (CoNS) among pregnant women in public health facilities in Yola, revealing a significant prevalence rate of 26.97%. The research highlights the high susceptibility of CoNS to certain antibiotics and the alarming presence of multi-drug resistant and extended spectrum beta-lactamase (ESBL) producing strains. This underscores the necessity for routine screening of pregnant women for CoNS to prevent potential gestational complications, providing crucial data for public health interventions and antibiotic stewardship programs. Full Abstract Coagulase negative staphylococci have been reported to be a frequent agent of uncomplicated UTI in young sexually active women which can also lead to symptomatic infection, low birth weight (LBW) babies and preterm delivery. This study was undertaken to determine the prevalence and characterize coagulase negative staphylococci among pregnant women in public health facilities in Yola. A total of 250 urine samples were collected from pregnant women attending antenatal clinic at Specialist Hospital and Boshang Clinic and Maternity both in Yola. The samples were cultured on cysteine lactose electrolyte deficient medium and isolates characterized using phenotypic methods. The prevalence of coagulase negative staphylococci from this study was 26.97%, Staphylococcus aureus 16.29% and Escherichia coli 36.51%. The frequency of CoNS was highest among age group of 36-40 years and least among 16-20 years (12.5%). CONS isolated from this study demonstrated high susceptibility to pefloxacin, ciprofloxacin, erythromycin, ceftriaxone and streptomycin. Some isolates showed high resistance to ampiclox, cefuroxime and amoxicillin. About 83% of the isolates had multiple antibiotic resistant indexes greater than 0.2 with about 25% of the antibiotic resistance being plasmid mediated. Furthermore, phenotypic screening using the double disk synergy test showed that 20 (40%) of the isolates were extended spectrum beta lactamase (ESBL) producing. This study revealed the presence of multi-drug resistant and ESBL producing coagulase negative staphylococci among pregnant women in the study area. There is therefore the need for pregnant women to be screened for coagulase negative staphylococci to avoid complications during gestation period.

Phenotypic investigation of Beta–Lactamase enzymes in multidrug resistant Klebsiella Pneumoniae clinically isolated in Diyala City /Iraq

Phenotypic investigation of Beta–Lactamase enzymes in multidrug resistant Klebsiella Pneumoniae clinically isolated in Diyala City /Iraq

Phenotypic detection of ESBL and Amp C beta lactamase among clinical isolates of Enterobacteriaceae

Phenotypic detection of ESBL and Amp C beta lactamase among clinical isolates of Enterobacteriaceae

Phenotypic and molecular characterization of extended spectrum- and metallo- beta lactamase producing Pseudomonas aeruginosa clinical isolates from Egypt.

Antimicrobial resistance among Pseudomonas aeruginosa (P. aeruginosa), a leading cause of nosocomial infections worldwide, is escalating. This study investigated the prevalence of extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) among 104 P. aeruginosa clinical isolates from Alexandria Main University Hospital, Alexandria, Egypt. Antimicrobial susceptibility testing was performed using agar dilution technique, or broth microdilution method in case of colistin. ESBL and MBL prevalence was assessed phenotypically and genotypically using polymerase chain reaction (PCR). The role of plasmids in mediating resistance to extended-spectrum β-lactams was studied via transformation technique using plasmids isolated fromceftazidime-resistant isolates. Antimicrobial susceptibility testing revealed alarming resistance rates to carbapenems, cephalosporins, and fluoroquinolones. Using PCR as the gold standard, phenotypic methods underestimated ESBL production while overestimating MBL production. Eighty-five isolates (81.7%) possessed only ESBL encoding genes, among which 69 isolates harbored a single ESBL gene [blaOXA-10 (n = 67) and blaPER (n = 2)]. Four ESBL-genotype combinations were detected: blaPER + blaOXA-10 (n = 8), blaVEB-1 + blaOXA-10 (n = 6), blaPSE + blaOXA-10 (n = 1), and blaPER + blaVEB-1 + blaOXA-10 (n = 1). Three isolates (2.9%) possessed only the MBL encoding gene blaVIM. Three ESBL + MBL- genotype combinations: blaOXA-10 + blaAIM, blaOXA-10 + blaVIM, and blaPER + blaOXA-10 + blaAIM were detected in 2, 1 and 1 isolate(s), respectively. Five plasmid preparations harboring blaVEB-1 and blaOXA-10 were successfully transformed into chemically competent Escherichia coli DH5α with transformation efficiencies ranging between6.8 × 10 3 and3.7 × 10 4 CFU/μg DNA plasmid. Selected tested transformants were ceftazidime-resistant and harbored plasmids carrying blaOXA-10. The study highlights the importance of the expeditious characterization of ESBLs and MBLs using genotypic methods among P. aeruginosa clinical isolates to hinder the development and dissemination of multidrug resistant strains.

Phenotypic identification of different β-Lactamases in intrinsic and acquired colistin resistant uropathogenic gram negative bacteria.

Identification of MBL, AmpC and ESBLs in colistin intrinsic and acquired resistant uropathogenic gram negative bacteria. Urine samples were collected from Hayatabad Medical Complex, Peshawar during 17 January to 30 June 2019. Collected urine samples were aseptically transported microbiology lab of Health Research Institution (HRI), National Institute of Health (NIH), Khyber Medical College, Peshawar and streaked on different media. Positive growth was identified by API-10s. Antibiotic sensitivity profile was done by Modified Kirby Bauer disc diffusion method. Detection of metallo βlactamases (MBL) production by Imipenem EDTA synergy test, Double Disc Synergy Test (DDST) for detection of ESBLs and D-test for the detection of inducible AmpC beta lactamases test was used. Colistin resistance was identified via broth micro dilution according to CLSI manual. Colistin resistant bacteria was divided in two categories; acquired and intrinsic resistant bacteria according to CLSI manual. Out of 2000 urine samples, 281(14%) gram-negative bacteria were isolated. Among positive samples, acquired colistin resistant bacteria were 241 and intrinsic resistant bacteria were 40 isolates. MBL was produce by twenty one (11.7%) E.coli and seventeen (40.5%) Pseudomonas aeruginosa. E. coli, Pseudomonas aeruginosa, Klebsiella Pneumoniae, Serratia Oderifora and Proteus Marblis were ESBLs producing bacteria. AmpC production was prevalent in fourteen (7.8%) E. coli and twelve (28.6%) Pseudomonas aeruginosa. Fifty-five samples showed resistance to colistin out of 241 samples. In colistin resistant bacteria, two E.coli were MBL, ESBLs, while one E.coli was ESBLs, AmpC co-producing bacteria. The most prevalent extended drug resistant bacteria were Pseudomonas aeruginosa (28.6%) and Escherichia coli (6.1%), While 155(86.6%) Escherichia coli, 25 (59.5%) Pseudomonas aeruginosa and 22 (95.7%) Serratia Oderifora was multi drug resistant bacteria. Current study concluded that ESBL, MBL AmpC enzymes and their co-expression was observed with colistin resistance in E.coli and Pseudomonas aeruginosa.

Molecular characterization of extended spectrum beta lactamase (ESβL) and quinolone (QNR) resistance genes in Escherichia Coli isolated from cloaca swabs of wild birds and poultry droppings in Jos Metropolis

Molecular characterization of extended spectrum beta lactamase (ESβL) and quinolone (QNR) resistance genes in Escherichia Coli isolated from cloaca swabs of wild birds and poultry droppings in Jos Metropolis

Maxillofacial Abscess et Causa Odontogenic Infection: A Case Report

Background: Odontogenic infection is an infection that occurs in the oral cavity caused by carious teeth and periodontal disease where the disease can spread to surrounding tissues to the face, jaw and neck. Maxillofacial abscess is a manifestation of periapical or periodontal infection. incicus, canicus or molar teeth, where periapical infection is the most frequent source of odontogenic infection compared to periodontal. Inflammation or damage to chronic dental problems can cause complications of abscesses in the surrounding area. The main complaint that causes sufferers to come to the hospital is pain in the abscess area. These complaints can also be accompanied by trismus, dysphagia, stridor caused by compression of the trachea, and even respiratory tract obstruction. Objective: To determine the progression of maxillofacial abscess so that medical management can be provided up to surgical incision and drainage. Case report: We report 2 cases of maxillofacial abscess due to odontogenic infection with management according to the progression of each case. Conclusion: The most common cause or etiology that can cause maxillofacial abscess is toothache. Management of maxillofacial abscesses begins with empirical antibiotics, which is the first step to reduce bacterial infections that produce beta lactamase. In maxillofacial abscesses, medical therapy can be given in the form of antibiotics combined with ceftriaxone with metronidazole, or meropenem with metronidazole and termination measures in the form of incision and drainage. Treatment can be chosen based on the presence or absence of warning signs and signs of complications. Incision and drainage is performed when complaints do not improve after administration of antibiotics, multiple abscesses and airway obstruction threaten the patient's life.

Simultaneous detection of phylogroups and ESBL genes in E. coli using Multiplex PCR

Background: Escherichia coli (E. coli) strains harbor various allelic versions of beta lactamase genes and their identification using conventional phenotypic tests is a tedious and time consuming task. In the present study, multiplex PCR is performed for the simulatanoues detection of E. coli phylogroups and extended-spectrum β-lactamase- (ESBL) genes.Methods: A total of 128 E. coli isolates from urine samples were screened for antibiotic resistance and expression of ESBL activity using phenotypic and genotypic methods. Uniplex and multiplex PCRs were used to detect E. coli phylogroup detrminants and blaCTX-M-15, blaOXA-1 and TEM1 genes. Chi Square test of independence was employed for evaluating significant levels at P value < 0.05. Results: Phylogroup B2 was detected as the predominant group (36%) followed by group D (30%), A (25%) and B1 (9%). The highest resistance was seen against nalidixic acid (100%) and the lowest against amoxicillin-clavulanic acid (55%). Significant P values were observed for resistance against cefotaxime and cefepime in the phylogroup B2 while resistance against cefoxitin, sulfamethoxazole and fosfomycin was significantly associated with group D. Combination disc diffusion test (CDDT) showed ESBL activity in 42% E. coli isolates. A significant association of blaCTX-M-15 gene was observed for phylogroup B2 (P = 0.007). Moreover, a combination genotype of blaCTX-M-15 and TEM1 was also found statistically prevalent in phylogroup B2 (P = 0.006).Conclusion: The study highlights the alarming rise in antibiotic resistance and delineates B2 a predominant phylogoup with a high prevalence of blaCTX-M-15 and TEM1 genes in urinary E. coli isolates.Keywords: UTI; E. Coli; Phylogenetic groups; ESBL genes; Multiplex PCR

Chromosomal and plasmid-encoded virulence and multidrug resistance of Escherichia coli ST58/24 infecting a 2-year-old sickle cell patient with sepsis in Kampala Uganda, East Africa

Sepsis and drug resistance represent a complex of the most common global causes of mortality in intensive care units (ICUs) especially among patients with comorbidities. Extraintestinal pathogenic Escherichia coli (ExPEC) strains are highly implicated in systemic infections, with multidrug resistance exacerbating the risk of chronic conditions and patient mortality. The diversity of virulence and evolution of multidrug resistance are yet to be fully deciphered. In this work, we aimed at unveiling the pathogens and their genomic determinants of virulence and drug resistance relevant to increased sepsis in a sickle cell child admitted to ICU. From a rectal swab, we isolated a strain of E. coli from the patient and phenotypically tested it against a panel of selected beta lactams, fluoroquinolones, macrolides, aminoglycosides and colistin. We then sequenced the entire genome and integrated multiple bioinformatic pipelines to divulge the virulence and multidrug resistance profiles of the isolate. Our results revealed that the isolate belongs to the sequence type (ST) 58/24, which (ST58), is a known ExPEC. With the use of PathogenFinder, we were able to confirm that this isolate is a human pathogen (p = 0.936). The assembled chromosome and two plasmids encode virulence factors related to capsule (antiphagocytosis), serum survival and resistance, type 6 secretion system (T6SS), multiple siderophores (iron acquisition), and biosynthetic gene clusters for polyketides and nonribosomal peptides exhibiting host cell damaging activity in silico. The genome also harbors multidrug resistance genotypes including extended spectrum beta lactamase (ESBL) genes such as blaTEM-1A/B, sulfonamide resistance genes sul1/2, fluoroquinolone resistance genes dfrA5 and nonsynonymous mutations of the gene pmrB, conferring intrinsic colistin resistance. Conclusively, this pathogen holds the potential to cause systemic infection and might exacerbate sickle cell anemia in the patient. The virulence and multidrug resistance profiles are encoded by both the chromosome and plasmids. Genomic surveillance of pathogens with multidrug resistance among patients with comorbidities is crucial for effective disease management.

Peptidoglycan modulation by Francisella tularensis

HAYDEN HESS, STUART CANTLAY, JOSEPH HORZEMPA, Department of Biomedical Sciences, West Liberty University, West Liberty, WV 26074 and MELANIE SAL, Department of Biology, West Virginia Wesleyan College, Buckhannon, WV 26201. Peptidoglycan modulation by Francisella tularensis. Peptidoglycan, a crucial component of bacterial cell walls, plays a fundamental role in maintaining cell shape, integrity, and resistance to osmotic pressure. Mycoplasmas are the only bacteria that do not produce peptidoglycan cell walls. Other peptidoglycan-producing bacteria are capable of transiently existing without a peptidoglycan as an “L-form”, but only on solid media. Preliminary observations made by our laboratory suggested that Francisella tularensis bacteria do not produce detectible levels of peptidoglycan while growing in liquid media. However, increasing salt concentration induces the production of peptidoglycan in all bacteria. In this study we confirmed and extended these observations by incubating bacteria with fluorescent D-alanine (which integrates into the peptidoglycan during synthesis). Fluorescence microscopy revealed that very few F. tularensis bacteria produce detectable peptidoglycan in low salt media, while seemingly all individual bacteria produce this layer in high salt media. Interestingly, the genome of F. tularensis encodes two distinct beta-lactamases. Here we show that both the wild-type F. tularensis LVS and beta-lactamase null mutant were both resistant to high levels of beta-lactam antibiotics in low salt liquid media. However, only the wild type and complemented mutant strains were resistant to beta-lactam antibiotics in high salt media while the beta lactamase null mutant was susceptible. These data further support the conclusion that F. tularensis does not produce, nor need, peptidoglycan in low salt liquid media. Future studies will investigate whether peptidoglycan modulation is required to avoid detection by the innate immune system.

Detection of multidrug-resistant organisms of concern including Stenotrophomonas maltophilia and Burkholderia cepacia at a referral hospital in Kenya.

Regular monitoring of bacterial susceptibility to antibiotics in clinical settings is key for ascertaining the current trends as well as re-establish empirical therapy. This study aimed to determine bacterial contaminants and their antimicrobial susceptibility patterns from medical equipment, inanimate surfaces and clinical samples obtained from Thika Level V Hospital (TLVH), Thika, in Central Kenya. Three hundred and five samples were collected between the period of March 2021 to November 2021 and comprised urine, pus swabs, catheter swabs, stool, and environmental samples. Bacterial identification and antimicrobial susceptibility were performed using VITEK 2 and disc diffusion respectively. We observed that Coagulase-negative Staphylococci (28 /160, 17.5%) were the most commonly isolated species from clinical samples followed by E. coli (22 /160 13.8%) and S. aureus (22/160, 13.8%). The bed rails were the mostly contaminated surface with S. aureus accounting for 14.2% (6/42). Among the clinical samples, pus swabs yielded the highest number of pathogens was pus (92/160). Trauma patients had the highest proportion of isolates (67/160, 41.8%). High level of antimicrobial resistance to key antimicrobials, particularly among Enterobacterales was observed. Extended Spectrum Beta Lactamase (ESBL) phenotype was noted in 65.9% (29/44) of enteric isolates. While further ESBL genetic confirmatory studies are needed, this study highlights the urgent need for actions that mitigate the spread of antibiotic-resistant bacteria.

Antimicrobial resistance in surgical infections: experience from open tibia fracture-related infection intraoperative tissue specimens

Background Antimicrobial resistance in surgical infections is known to have significant morbidity and mortality in extreme cases on top of increased costs in medical expenditure. This study aimed to analyze antimicrobial resistance patterns of microbes in open tibia fracture-related infection (FRI) using intraoperative tissue samples. Methods Between January and June 2022, a descriptive cross-sectional observational study was conducted involving patients aged 18 and above with open tibial shaft fractures. Microbiological culture and sensitivity of three intraoperative deep tissue and bone samples taken by sterile techniques using separate instruments in patients with infection. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method along with biomechanical tests for microbial identification. Results Fifty-seven deep tissue samples were taken from 19 patients with FRI who underwent surgery during the study period were analyzed. Almost all (96.5%) intraoperative tissue samples were culture-positive identifying 73 bacterial isolates out of which 57.9% were polymicrobial. The most frequent isolated bacteria were Gram-negative bacteria 56 (76.7%) with a predominance of Proteus spp 13 (17.8%). Methicilin Resistance Staphyaureus comprised 12 (16.4%) of the isolates whereas Inducible Clindamycin resistance was identified in 8 (57.1%) of Staphyloccus aureus isolates. More than half of the isolates 30 (53.6%) comprised of Extended Spectrum Beta Lactamase producing bacteria. There was high resistance to Cephalosporins and Amoxyclavulanic acid as the efficacy was low ranging from 28.2, 27.8, and 30.0% for cefotaxime, ceftazidime and amoxicillin/clavulanic acid, respectively. Almost all Gram-negative bacteria 47 (83.9%) had multidrug resistance pattern except for Pseudomonas aureginosa that had 77.8 to 88.9% susceptibility to all tested antibiotics. Conclusion High resistance to cephalosporins in patients with delayed or late infection in open tibia FRI is alarming and further studies to establish causes are indicated.

Extended Spectrum Beta Lactamase Escherichia Coli in Bagmati River, Kathmandu Valley.

Antimicrobial resistance organisms in the peripheral communities of an environment can be predicted by the presence of extended-spectrum beta-lactamase Escherichia coli in that environment. The close connectivity between humans and water sources can facilitate the entry of antimicrobial resistant organisms into the human ecosystem. The aim of this study was to assess beta lactamase producing Escherichia coli from Bagmati river within Kathmandu valley. In the year 2020, a cross-sectional study was conducted on water samples collected from 66 locations along the Bagmati River. Coliforms were isolated by five tubes dilution method and identified by cultural and biochemical tests. Further Escherichia coli was isolated in eosin methylene blue agar at 44.5 ⁰C. Antibiotic susceptibility test was performed by Kirby Bauer disk diffusion methods. Beta lactamase gene types were detected by using conventional multiplex polymerase chain reaction. A total of 615 bacterial isolates were identified among which 39 % (n=241) were Escherichia coli. Extended spectrum beta lactamase producing Escherichia coli was confirmed in 16.6 % (40/241) of total Escherichia coli isolates. Among 66 sites this isolate was detected in 26 (40 %) sampling sites excluding upstream regions. All the Escherichia coli isolates were multidrug resistance showing higher percentage (>99 %) of resistant for penicillin, tetracycline and erythromycin antibiotics. There were significant differences in resistance rate for cefotaxime and ceftazidime by extended spectrum beta lactamase producing and non-producing Escherichia coli (p<0.05). Presence of multidrug resistance extended spectrum beta lactamase producing Escherichia coli in river streams suggests the chances of circulating within river system and hence transmitting in human community. Bagmati river; drug resistance; escherichia coli; human.

Etiologies, risk factors, and antibiotic pattern of lower respiratory tract infection in patients coming to Deccan College of Medical Sciences, Hyderabad, South India

Background. Lower Respiratory Tract Infections (LRTI) impose a huge problem on society due to their tenacious and unescapable health problems, and they were the reasons for consultation and hospitalization. Patients with LRTI were present with a wide spectrum of diseases that range from life-threatening infections to minor self-limiting illnesses. Materials and methods. Sputum samples from 310 patients with complaints of lower respiratory tract infections were collected and analyzed. After microscopic analysis, 30 were excluded from the study. Of the 280 that were included in the study, 171 were males and 109 were females. The age group between 56 and 65 years comprised the highest number of patients in the study. Different antibiotics were used to check antibiotic sensitivity patterns against isolated Gram-positive and negative bacteria. Results. Of the 280 samples processed, 122 (43.5%) were culture-positive. Among the 122 bacterial isolates, the predominant organism was Klebsiella pneumoniae 55 (45%). The most common predisposing factor identified in 115 (37%) patients was smoking. Using the Double Disk Synergy Test, 11 (20%) out of a total of 55 K. pneumoniae isolates and 4 (30.7%) out of 13 Pseudomonas isolates showed Extended Spectrum Beta Lactamases (ESBL). The Klebsiella and Pseudomonas isolates showed resistance to 2nd and 3rd generation Cephalosporins. Conclusion. Because of different geographical regions and conditions, the etiology and the antibiotic sensitivity patterns of LRTI vary, so the etiology, predisposing factors, and the antibiotic sensitivity pattern of LRTI need to be updated regularly. The diagnostic facilities for early and rapid identification of LRTI also need to be improved.

What Is the Rate of Antimicrobial Resistance of a Prosthetic Joint Infection in a Major Orthopaedic Centre?

Periprosthetic joint infections (PJIs) are important factors in decreasing the success of hip and knee arthroplasties. It is a necessity to explore the epidemiological data and develop applications for rational antibiotic use, to address future infection control concerns. We aimed to investigate the microorganisms that were responsible and the related antibiograms in 121 patients with PJI, who were managed by two-stage revision surgery. Patients' data records, demographics, comorbidities, sites of arthroplasty, synovial fluid and deep tissue culture results and antibiotic treatment were summarized on a standardized case report form. There were 43 (35.5%) culture-negative PJI cases and 12 (9.9%) polymicrobial growths. The causative pathogens included Gram-positive (50.4%) and Gram-negative microorganisms (23.1%) and fungi (0.8%). Methicillin resistance was 64.3% for S. aureus and 89.5% for coagulase-negative staphylococcus (CoNS). The extended spectrum beta lactamase (ESBL) rate for Enterobacteriaceae was 68.4%. This study shows that antibiotic resistance is encountered in more than half of the cases, which is valid for all microorganisms most common in PJI. The success of treatment decreases significantly in cases where antibiotic-resistant microorganisms are isolated or in cases where the culture is negative.

Identification of Extended Spectrum Beta Lactamases Producing Pseudomonas aeruginosa from Subclinical Mastitis Milk Samples in an Organized Dairy Farm of SVVU, Andhra Pradesh

The present study was conducted during August 2021 at Buffalo Research Station, Venkatarammanagudem of West Godavari District, Andhra Pradesh, India and was aimed to detect the presence of extended-spectrum beta-lactamases (ESBL) producing P. aeruginosa from sub-clinical mastitis that are apparently healthy Murrah buffaloes. Inflammation of the udder by microbial infection is one of the leading economic disease in the dairy sector. Most of the pathogens especially Pseudomonas aeruginosa are refractory to the antibiotic theraphy. Nowadays, the antimicrobial resistance owed by the bacteria is at an alarming rate. Pseudomonas aeruginosa, a multi drug resistant pathogen carry the extended spectrum beta lactamase genes in its plasmids and thus become resistant to antibiotic therapy. A total of 276 milk samples were collected from 69 milch animals in the month of August, 2021 comprising from all the four quarters of each buffalo. Nine (n=9) (3.26%) P. aeruginosa isolates were identified from the sub-clinical mastitis milk samples from the total 276 samples collected in the study. The isolates on morphological analysis were typical to P. aeruginosa. Seven isolates were positive for phenotypical beta-lactamases production. A total of 1 and 2 isolates were found reactive of the blaSHV and blaOXA genes, and two isolates harboured both blaSHV and blaOXA genes, respectively on PCR assay. No blaTEM gene was found in the isolates. Antibiogram of the ESBL producing P. aeruginosa isolates (n=7) possessed 100% resistance against most of the commonly used antimicrobials like ampicillin, amoxycillin, clindamycin, co-trimoxazole oxytetracycline, streptomycin and ceftriaxone (85%). The P. aeruginosa isolates were sensitive to amikacin (100%), ciprofloxacin (87.4%), gentamicin (84%), norfloxacin (84.8%) and enrofloxacin (82%).

BACTERIOLOGICAL PROFILE AND ANTIBIOGRAM PATTERN IN ISOLATES FROM NEONATAL SEPSIS IN A TERTIARY CARE HOSPITAL

Objective: To determine the microbiological profile and their Antibiogram pattern in isolates from neonatal sepsis.&#x0D; Methods: This study was conducted from October 2022 to January 15th 2023. Total 663 blood samples received from NICU, which were processed in the department of microbiology Andhra Medical College, Visakhapatnam. Organisms were identified by conventional methods and an antibiotic susceptibility test was done by Kirby Bauer disc diffusion method as per CLSI guidelines.&#x0D; Results: Out of 663 samples 200 (30.16%) are culture positives, in which males are more affected than females, that is 103 (51.5%). Among the culture positives, the most predominant isolate was klebsiella species 106 (53%) followed by pseudomonas 28 (14%) Escherichia coli 28 (14%) Acinetobacter 24 (12%), MRSA 11 (0.05%), MSSA 3(0.015%). Regarding its antibiogram, klebsiella species and Escherichia coli were most sensitive to penicillins+beta lactamase inhibitors (83%), fluroquinolones (75%) and aminoglycosides (75%), respectively. Pseudomonas, Acinetobacter was sensitive to penicillins+betalactamase inhibitors (100%) and aminoglycosides (72%). Gram-positive organisms were mostly sensitive to vancomycin, linezolid, aminoglycosides (MRSA) and cefoxitin (MSSA). There was widespread resistance to third-generation cephalosporins (77.77%) among gram-negative organisms.&#x0D; Conclusion: Gram negative bacteria are the most common cause of neonatal sepsis and klebsiella species are the predominant pathogens. These gram negative bacteria were resistant to cephalosporins. Antibiogram helps as a guide to antimicrobial therapy and resistance to antibiotics, as it is the common problem that causes ineffectiveness of empirical treatment.

Detection of mcr-1 gene of plasmid-mediated colistin resistance in extended spectrum beta lactamase (ESBL) producing Escherichia coli in Khartoum State – Sudan

Detection of mcr-1 gene of plasmid-mediated colistin resistance in extended spectrum beta lactamase (ESBL) producing Escherichia coli in Khartoum State – Sudan

Transition mutation bias is crucial to adaptive extended spectrum beta lactamase (ESBL) resistance evolution

The importance of slow accumulation of mutation in the nucleic acids of bacteria and the possibility of organismal transcriptional modification to suit their adaptation are key drivers favouring natural selection and subsequently adaptive evolution. This study was aimed at providing insight into factors influencing adaptive extended spectrum beta lactamase (ESBL) resistance evolution. A total of twenty-six (26) extended spectrum beta lactamase-producing Gram-negative bacteria isolated in our previous study were subjected to uniplex and multiplex polymerase chain reaction (PCR) and sequencing prior to mutation discovery analyses, while the maximum likelihood value, transition-transversion ratio, tajimas neutrality test, nucleotide diversity and selection analyses were estimated following standard recommended protocols. Results obtained depict the PCR discriminated ESBL alleles as; TEM (n = 11.5 %), CTX-M (n = 15.4 %), SHV (n = 19.2 %) while the co-occurred ESBL alleles were estimated as CTX-M and TEM (n = 3.85 %), CTX-M and SHV (n = 15.4 %), TEM and SHV (n = 23.1 %), CTX-M, TEM and SHV (n = 11.5 %). The transition, transversion, deletion and insertion distribution pattern were evaluated as; TEM (46, 39,11 and 4 %), SHV (50, 31, 8 and 11 %) and CTX-M (60, 21,12 and 7 %) (p < 0.05) respectively. The maximum likelihood value, transition-transversion ratio, tajimas neutrality test, nucleotide diversity and selection analyses for TEM, SHV and CTX-M were (−8436, 1.18, 5.2, 62 % and 84.9 %,), (−8321, 1.60, 5.4, 68.9 % and 97.8 %) and (−7284, 2.86, 6.0, 55.2 % and 77.2 %) sequentially. Our findings therefore have shown that adaptive ESBL resistance evolution is driven by transition mutation, positive natural selection and ESBL gene flow. It is thus imperative to state that understanding these adaptive resistance driven factors and how they operate is crucial to deciphering the fundamental principles of adaptive evolution that might help circumvent the global challenges of antibiotic resistance.