Multidrug-Resistant Bacteria with ESBL Genes: A Growing Threat Among HIV Patients in Nepal

Background Bacterial opportunistic infections are quite common in HIV patients. Besides HIV-TB coinfection, lower respiratory tract infections by multidrug-resistant bacteria cause significant morbidity and mortality among HIV patients. This study was done to evaluate the bacterial coinfection of LRT and detect plasmid-mediated blaTEM and blaCTX−M genes among Extended-Spectrum β-Lactamase (ESBL) producing isolates from sputum samples in HIV patients. Methods A total of 263 sputum samples from HIV-positive cases were processed with standard microbiological methods to isolate and identify the possible pathogens. The identified bacterial isolates were assessed for antibiotic susceptibility pattern by using modified Kirby Bauer disk diffusion method following Clinical Laboratory Standard Institute (CLSI) guidelines. Plasmid DNA was extracted from multidrug-resistant and ESBL producers for screening of ESBL genes; blaCTX−M and blaTEM by conventional PCR method using specific primers. Results Of 263 sputum samples, 67 (25.48%) were culture positive showing Klebsiella pneumoniae; 17(25.37%) as the most predominant one. A higher rate of infection (4/8, 50%) was observed among old-aged people of 61 -70 years, whereas no infection was observed below 20 years. About 30.0% (15/50) of smokers, 32.86% (23/70) cases with previous pulmonary tuberculosis and 52.38% (11/21) with CD4 count <200 cells/µl were found to be susceptible to LRTIs. Among 53 bacterial isolates, 52.83% (n=28) were multidrug-resistant and 43.4% (n=23) were ESBL producers. All ESBL producers were sensitive to Colistin and Polymyxin B. Of 23 ESBL producers, 47.83% (11/23) and 8.6% (2/23) possessed only blaCTX−M and blaTEM genes respectively and 43.48% (10/23) possessed both ESBL genes. Conclusion The increasing rate of MDR bacterial infections mainly ESBL producers of LRTIs causes difficulty in the management of diseases leading to high morbidity and mortality of HIV patients.

Evaluation of cell surface hydrophobicity and biofilm formation as pathogenic determinants among ESBL producing uropathogenic Escherichia coli

The attachment of the bacteria to the host cell and ability to invade the cell are regarded as important steps in the infectious process. The hydrophobicity of the microbial surface plays a critical role in the adherence of bacteria to the surface. The ability of biofilm formation can increase survival chance of microorganism, as cell growing in biofilm are highly resistant to the components of the immune system and many antimicrobial agents. Infection caused by ESBL- producers are associated with severe adverse outcomes and may be related to increased virulence of these strains.: A total of 100 urinary were selected for the study, of which 50 strains were from ESBL producers and 50 from non- ESBL-producing uropathogenic(UPEC) strains. The urinary isolates that were resistant to at least one of the three indicator cephalosporins (cefotaxime, cefpodoxime and ceftazidime) were tested for ESBL production by quantitative E-strip method. All the 100 urinary strains were tested for cell surface hydrophobicity (CSH) by salt aggregation method and Biofilm production by tissue culture plate method.Among ESBL producers, 19 (38%) were CSH positive and 34 (68%) were biofilm producers. However among non-ESBL producers, 05 (10%) were CSH positive and 12 (24%) were biofilm producers. Statistically significant difference (&#60;0.001) was seen in the occurrence of CSH and biofilm production between ESBL and non ESBL producing UPEC isolates.In the present study, it was found that the ESBL producing isolates had a higher ability to form biofilm and CSH; both of them are among the important virulence factors associated with cell surface adherence which is the first step in bacterial infection.

Antimicrobial Susceptibility Pattern and ESBL Prevalence of Bacteria Isolated from Street Vended Snacks

Aims: The objective of the study was to ascertain the antimicrobial susceptibility pattern and ESBL prevalence of bacteria isolated from snacks. Place and Duration of Study: Department of Microbiology (Laboratory Unit) Michael Okpara University of Agriculture Umudike. Methodology: The snacks were mashed aseptically, serially diluted and inoculated onto nutrient agar and MacConkey agar. Isolates were identified using standard microbiological procedures. Antimicrobial susceptibility of the isolates and ESBL detection was done using disk diffusion method. ESBL production was confirmed using Double Disc Synergy Test (DDST) method following CLSI recommendations. Results: Escherichia coli, Salmonella Typhi, Staphylococcus aureus and Klebsiella pneumoniae were the bacteria isolated with Escherichia coli as the most prevalent isolate with 42% occurrence in the samples screened. There was significant difference in the sensitivity of the bacteria isolates to the different antibiotics used at P=0.05. Salmonella Typhi isolates exhibited highest resistance to an antibiotic with 86% resistance to ciprofloxacin while Klebsiella pneumoniae isolates exhibited the lowest resistance to an antibiotic with 10% resistance to cefotaxime. Among the Gram-negative bacteria, 36% of suspected ESBL producing E. coli isolates were confirmed as ESBL producers indicating the highest occurrence. Conclusion: The study confirmed the presence of bacteria in street vended snacks which exhibited high resistance to antibiotics that could be attributed to the presence of ESBL producers among the isolates.

The Carrier Rate of Extended Spectrum Beta Lactamase (ESBL) Producing Bacteria in Cockroaches (Periplaneta americana) in Hospital and Community

Highlight :Bacteriologically for colonization of ESBL producing Enterobacteriaceae in cockroaches (Periplaneta americana) were analyzed.The prevalence of ESBL producing bacteria among cockroaches in hospitals is bigger than in households.Abstract: Cockroach (Periplaneta americana) is one of the vectors in the environment that can transmit disease. Cockroaches can act as potential mechanical vectors of antibiotic resistant bacteria. Enterobacteriaceae is a gram-negative bacteria that has natural habitats in the digestive tract of humans and animals. Enterobacteriaceae that produce Extended Spectrum β-lactamases (ESBLs) have emerged as major pathogens in hospitals. The study analyzed the prevalence of ESBL producing bacteria in cockroaches that lived in hospitals and residential homes. In this study, a total of 200 cockroaches consisting of 100 cockroaches from the hospital environment and 100 cockroaches from the residential environment were analyzed bacteriologically for colonization of ESBL producing Enterobacteriaceae. The specimen of the alimentary tract was taken and sub-cultured in MacConkey agar supplemented with cefotaxime 2 ug/ml. Growth colonies were suggested as an ESBL-producing bacteria, then were confirmed as ESBL producers by the Double Disk Synergy Test (DDST). The ESBL gene was detected by Polymerase Chain Reaction (PCR). Among 100 household cockroach samples, 14 (14%) were identified as ESBL producers, while 100 hospital cockroaches were 26 (26%) positive ESBL. The ESBL gene, in hospital cockroach were identified of CTXM 19 (19%), SHV 7 (7%), and not any TEM gene, while among household cockroaches were identified CTXM 2 (2%), SHV 11 (11%), and also not detected TEM ESBL gene. Among ESBL genes, only the CTXM gene was significantly different between household and hospital cockroaches.

Characterisation of AmpC / ESBL genes in some pathogen gram-negatives isolated from clinical cases of livestock and companion animals

This study was aimed to search and characterize the AmpC and/or ESBL genes of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa isolated from clinical cases of local livestock and companion animals between 2017 and 2019. A total of eight ceftiofur-resistant E. coli (n= 7) and ceftiofur-resistant K. pneumoniae (n= 1) and seven P. aeruginosa were isolated from different cases in local animals. By combination disc method, six E. coli isolates and one K. pneumoniae isolate were found to be ESBL producers. By combination of the disc method and double disc synergy test, no P. aeruginosa isolates were found as ESBL producers. In the agar disc diffusion test (ADDT) performed with cefoxitin and cefoxitin-boronic, only one E. coli was determined as AmpC producer. In ESBL-producing isolates, only the CTX-M class gene was detected by polymerase chain reaction (PCR) and subsequent sequence analysis revealed CTX-M-3 and CTX-M-15 variants. An AmpC positive E. coli isolate was found to carry plasmidic ampC gene in cmy-2 variant from CIT family. It was observed that P. aeruginosa isolates did not carry the plasmidic ampC gene. After the chromosomal ampC gene of one P. aeruginosa was amplified by PCR and sequenced, R79Q and T105A mutations in the chromosomal ampC gene was revealed. This showed that overproduction of the ampC enzyme is involved in the resistance to β-lactams in P. aeruginosa isolates in the study.

Antimicrobial resistance in wastewater of Yangon Region, Myanmar from one health perspective

Background: Antibiotic resistance is an emerging concern both for public and animal health globally and also threatens the achievements of modern medicine. This study aimed to generate the baseline data of drug resistance pathogens in diversity of waste water of Yangon Region, Myanmar.Methods: A cross-sectional descriptive study was conducted from January to July 2021. A total of forty samples of wastewater (two samples each from ten hospitals, one sample each from five poultry farms, five aquacultures and ten community drains) were aseptically collected, transported in ice box and processed following standard procedure for bacterial isolation and detection of antibiotic sensitivity pattern. Identification and antibiotic susceptibility testing of isolated colonies were done by VITEK 2 compact system.Results: A total of 106 bacterial isolates were identified and 50% were from hospitals, 31.1%were from community drains and 9.4% each from poultry farms and aquacultures. The most frequently identified isolates were Enterobacteriaceae (65.1%) followed by Acinetobacter species (11.3%) and Pseudomonas species (8.5%). Among the isolated organisms, ESBL producers and Carbapenemase producer were 7.5% and 0.9% respectively. ESBL producers (62.5%) were resistant to cefuroxime, cefuroxime-axetil, cefotaxime, ceftriaxone and minocycline. Carbapenem resistant Enterobacteriaceae was multidrug resistant but sensitive to amikacin, tigecycline and cefaclor.Conclusions: The proportion of antibiotic resistant bacteria are higher in hospital wastewater than other sites. Hence proper treatment plant for hospital wastewater should be installed and need to mitigate antibiotic resistance with a ‘one-health’ approach.

Effective Treatment against ESBL-Producing Klebsiella pneumoniae through Synergism of the Photodynamic Activity of Re (I) Compounds with Beta-Lactams

Background: Extended-spectrum beta-lactamase (ESBL) and carbapenemase (KPC+) producing Klebsiella pneumoniae are multidrug-resistant bacteria (MDR) with the highest risk to human health. The significant reduction of new antibiotics development can be overcome by complementing with alternative therapies, such as antimicrobial photodynamic therapy (aPDI). Through photosensitizer (PS) compounds, aPDI produces local oxidative stress-activated by light (photooxidative stress), nonspecifically killing bacteria. Methodology: Bimetallic Re(I)-based compounds, PSRe-µL1 and PSRe-µL2, were tested in aPDI and compared with a Ru(II)-based PS positive control. The ability of PSRe-µL1 and PSRe-µL2 to inhibit K. pneumoniae was evaluated under a photon flux of 17 µW/cm2. In addition, an improved aPDI effect with imipenem on KPC+ bacteria and a synergistic effect with cefotaxime on ESBL producers of a collection of 118 clinical isolates of K. pneumoniae was determined. Furthermore, trypan blue exclusion assays determined the PS cytotoxicity on mammalian cells. Results: At a minimum dose of 4 µg/mL, both the PSRe-µL1 and PSRe-µL2 significantly inhibited in 3log10 (>99.9%) the bacterial growth and showed a lethality of 60 and 30 min of light exposure, respectively. Furthermore, they were active on clinical isolates of K. pneumoniae at 3–6 log10. Additionally, a remarkably increased effectiveness of aPDI was observed over KPC+ bacteria when mixed with imipenem, and a synergistic effect from 3 to 6log10 over ESBL producers of K. pneumoniae clinic isolates when mixed with cefotaxime was determined for both PSs. Furthermore, the compounds show no dark toxicity and low light-dependent toxicity in vitro to mammalian HEp-2 and HEK293 cells. Conclusion: Compounds PSRe-µL1 and PSRe-µL2 produce an effective and synergistic aPDI effect on KPC+, ESBL, and clinical isolates of K. pneumoniae and have low cytotoxicity in mammalian cells.

598. A 3-Year Evaluation of Antibiotic Resistance Patterns in Gram-Negative Genitourinary Tract Infections Treated in Outpatient Infusion Centers (POICs)

Background Resistant Gram-negative pathogens (GNP) are common causes of genitourinary tract infections (GUI) often requiring outpatient parenteral antibiotic therapy (OPAT). Data are sparse regarding antibiotic resistance of GNP in patients (pts) treated with OPAT. We analyzed GNP of GUI pts treated in Infectious Disease OICs over a 3-year period stratified by location prior to OPAT. Methods Records from 18 POICs were queried for GUI pts with ≥1 GNP receiving OPAT from 2018 to 2020. Demographics, pt location prior to OPAT, infection type, year of therapy, and GNP were recorded. Antibiotic resistance patterns were defined as extended-spectrum beta-lactamase (ESBL) or multi-drug resistant (MDR). Chi Square and Fisher’s exact test were used to determine if ESBL status was associated with GNP or location prior to OPAT (hospital vs. community). The Cochran-Armitage test was used to analyze temporal trend in ESBL expression. Statistical significance was defined as P&lt; 0.05 for all tests. Results A total of 634 GNP were identified in 601 pts (mean age: 64±16, 58% female). Infections were 75% complicated urinary tract infection, 20% pyelonephritis, and 5% prostatitis/other. Overall, 56% (n=339) were treated directly from the community and 44% (n=262) following hospital discharge. GNP isolated were 56% E. coli, 19% Pseudomonas spp., 16% Klebsiella spp. and 9% others. Of the 611 GNP with potential to express ESBL, 43% (n=265) were ESBL producers (Table 1). Significantly more ESBL-producing GNP occurred in pts discharged from a hospital prior to OPAT compared to the community (53% vs. 36%, P&lt; 0.001). Overall, the incidence of MDR constituted 36% (n=231) of GNP, which did not differ by location prior to OPAT. Evaluation of ESBL incidence by year showed a significant increase from 2018 to 2020 (P=0.03). Although a slight increase in MDR was noted from 2018 to 2020, this was not significant (Figure 1). Table 1. Frequency of ESBL and MDR by Location prior to OPAT Figure 2. Prevalence of ESBL producers and MDR Pathogens by Year Conclusion Resistant GNP were observed in the OPAT setting for GUI with both ESBL and MDR pathogens. We saw a significantly higher rate of ESBL with GNP from hospital discharged pts compared to community-acquired infections and an increase in the overall incidence of ESBL over time. Management of Gram-negative genitourinary infections in the OPAT setting requires close monitoring of emerging resistance patterns. Disclosures Kimberly A. Couch, PharmD, MA, FIDSA, FASHP, AbbVie (Speaker's Bureau) Lucinda J. Van Anglen, PharmD, Merck & Co. (Research Grant or Support)

1259. Carbapenems Versus Non-carbapenem Beta-Lactams for the Treatment of Ceftriaxone-Susceptible and Piperacillin-Tazobactam-Nonsusceptible Enterobacterales Isolates

Background Ceftriaxone-susceptible (CRO-S) and piperacillin-tazobactam-non susceptible (TZP-NS) Enterobacterales isolates have become a frequently isolated phenotype emerging in practice. The genotypic profile is still not clearly elucidated, although prior genotypic sequencing data of these isolates with this phenotypic profile suggests that they are not extended-spectrum beta-lactamase (ESBL) producers. Due to the unfamiliarity with this phenotype and the potential for overuse of broad-spectrum antibiotics, we investigated the clinical outcomes of CRO-S/TZP-NS isolates with carbapenem versus non-carbapenem beta-lactam (NCBL) therapy. Methods This was a retrospective chart review of patients with a diagnosed infection caused by a CRO-S/TZP-NS Enterobacterales isolate admitted to any of the three NYU hospitals: Long Island, Tisch, or Brooklyn campuses, treated with a beta-lactam (BL) antibiotic from October 2015 to October 2020. The primary outcome was treatment failure defined as an escalation of antibiotics due to clinical worsening, 30-day all-cause mortality, or relapse of infection with the same genus and species. Patients who received ≥ 72 consecutive hours of BL antibiotics were considered to be on definitive therapy. Results A total of 111 patients were included in this study, 9 in the carbapenem group and 102 in the NCBL group. There was no statistically significant difference in the clinical failure rate between the two groups (0% vs 10.8% respectively, P=0.56). A univariate analysis assessed the association of clinical failure with TZP, CRO, cefpodoxime, cefepime, and 1st-3rd generation cephalosporins grouped. There were no statistically significant increases in 30-day treatment failure in any of the individual categories. Conclusion There were no statistically significant differences in 30-day failure with the use of carbapenem vs NCBL antibiotics. No individual BLs or classes were associated with an increased risk of clinical failure. This study suggests that there is a role for NCBL antibiotics for Enterobacterales isolates with this phenotypic presentation and supports prior data that they are less likely to be ESBL producers. Prospective studies are warranted to confirm these findings. Disclosures All Authors: No reported disclosures

In vitro susceptibility of ceftolozane/tazobactam against typhoidal, non-typhoidal and extended spectrum β-lactamase-producing Salmonella

Both typhoidal and non-typhoidal salmonellae are included in the top 15 drug-resistant threats described by the Center for Disease Control and Prevention of the United States. There is an urgent need to look for alternative antibiotics for the treatment of Salmonella infections. We examined the in vitro susceptibilities of ceftolozane/tazobactam and six other antibiotics on typhoidal and non-typhoidal salmonellae, including isolates that are extended-spectrum β-lactamase (ESBL)-positive, using the broth microdilution test. Of the 313 (52 typhoidal and 261 non-typhoidal) Salmonella isolates tested, 98.7% were susceptible to ceftolozane/tazobactam. Based on the overall MIC 50/90 values, Salmonella isolates were more susceptible to ceftolozane/tazobactam (0.25/0.5 mg/L) compared to all other comparator agents: ampicillin (≥64/≥64 mg/L), levofloxacin (0.25/1 mg/L), azithromycin (4/16 mg/L), ceftriaxone (≤0.25/4 mg/L), chloramphenicol (8/≥64 mg/L) and trimethoprim/sulfamethoxazole (1/≥8 mg/L). When comparing the activity of the antimicrobial agents against non-typhoidal Salmonella isolates according to their serogroup, ceftolozane/tazobactam had the highest activity (100%) against Salmonella serogroups D, G, I and Q isolates, whereas the lowest activity (85.7%) was observed against serogroup E isolates. All the 10 ESBL-producing Salmonella (all non-typhoidal) isolates, of which 8 were CTX-M-55-producers and 2 were CTX-M-65-producers, were sensitive to ceftolozane/tazobactam albeit with a higher MIC 50/90 value (1/2 mg/L) than non-ESBL-producers (0.25/0.5 mg/L). In summary, our data indicate that ceftolozane/tazobactam is active against most strains of both typhoidal and non-typhoidal salmonellae and also active against ESBL-producing salmonellae.