Clinically Isolated β-Lactam-Resistant Gram-Negative Bacilli in a Philippine Tertiary Care Hospital Harbor Multi-Class β-Lactamase Genes

• Published in: Pathogens (Basel) Vol. 12; no. 8; p. 1019
• Main Authors: Abordo, Alecks Megxel S, Carascal, Mark B, Remenyi, Roland, Dalisay, Doralyn S, Saludes, Jonel P
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2023; MDPI
• Subjects: Amides; antibiotic resistance; Antibiotics; Antimicrobial agents; Bacteria; Beta lactamases; Carbapenems; Cephalosporins; Disease control; Drug resistance; Drug resistance in microorganisms; Drug therapy; E coli; Genes; Genetic aspects; Genotype & phenotype; Gram-negative bacilli; Gram-negative bacteria; Gram-negative bacterial infections; Hospitals; Identification and classification; Klebsiella; Laboratories; Metallography; Pathogens; Penicillin; Philippines; Pseudomonas aeruginosa; Risk factors; Sequence analysis; β Lactamase; β-Lactam antibiotics; Philippines; United Kingdom > UK; France; Germany
• ISSN: 2076-0817; 2076-0817
• DOI: 10.3390/pathogens12081019

In the Philippines, data are scarce on the co-occurrence of multiple β-lactamases (BLs) in clinically isolated Gram-negative bacilli. To investigate this phenomenon, we characterized BLs from various β-lactam-resistant Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa isolated from a Philippine tertiary care hospital. The selected Gram-negative bacilli (n = 29) were resistant to either third-generation cephalosporins (resistance category 1 (RC1)), cephalosporins and penicillin-β-lactamase inhibitors (RC2), or carbapenems (RC3). Isolates resistant to other classes of antibiotics but susceptible to early-generation β-lactams were also selected (RC4). All isolates underwent antibiotic susceptibility testing, disk-diffusion-based BL detection assays, and PCR with sequence analysis of extended-spectrum BLs (ESBLs), metallo-BLs, AmpC BLs, and oxacillinases. Among the study isolates, 26/29 harbored multi-class BLs. All RC1 isolates produced ESBLs, with blaCTX-M as the dominant (19/29) gene. RC2 isolates produced ESBLs, four of which harbored blaTEM plus blaOXA-1 or other ESBL genes. RC3 isolates carried blaNDM and blaIMP, particularly in three of the metallo-BL producers. RC4 Enterobacteriaceae carried blaCTX-M, blaTEM, and blaOXA-24-like, while A. baumannii and P. aeruginosa in this category carried either blaIMP or blaOXA-24. Genotypic profiling, in complement with phenotypic characterization, revealed multi-class BLs and cryptic metallo-BLs among β-lactam-resistant Gram-negative bacilli.