Abstract:
The distribution of antimicrobial resistance in major pathogens was analyzed in a tertiary care hospital of Lodhran, Pakistan. Altogether, 1910 patients diagnosed and treated at Shahida Islam Medical Complex Hospital from December 2023 to August 2025 were selected. The antimicrobial resistance of major bacterial and fungal pathogens was quantified, and logistic regression analysis was used to identify the risk factors for infection. Methicillin-resistant
Staphylococcus aureus
(MRSA) isolates retained susceptibility to vancomycin (58.3%), while ceftazidime/avibactam showed activity against
Escherichia coli
(80%),
Klebsiella pneumoniae
(82%), and
Pseudomonas aeruginosa
(78%). Vancomycin-resistant Enterococcus (VRE) demonstrated resistance to nearly all antibiotics. PCR confirmed TEM and SHV in 23/51 (45%) of
E. coli
isolates, while in
K. pneumoniae
TEM and SHV were each detected in 20/35 (56%). Among
P. aeruginosa
isolates, VIM, NDM, and OXA-48 were each present in 14/37 (37%). The
mecA
was found in 47/49 (95%) of
S. aureus
isolates (MRSA),
vanA
in 34/49 (70%) of
S. aureus
(VRSA), and
vanA
in 34/43 (80%) of
Enterococcus
isolates (VRE). MLST analysis of representative multidrug-resistant isolates identified ST131 (1/3, 33%) among
E. coli
, ST11 (1/3, 33%) and ST258 (1/3, 33%) among
K. pneumoniae
, ST175 (1/3, 33%) and ST233 (1/3, 33%) among
P. aeruginosa
, ST5 (1/3, 33%) and ST22 (1/3, 33%) among
S. aureus
, and ST17 (1/3, 33%) among
Enterococcus
spp. PCA revealed distinct clustering of species, with Gram-negatives overlapping, Gram-positives forming separate groups, and fungi clustering independently. Logistic regression identified age ≥65, ICU admission, comorbidities, prior antibiotic exposure, invasive procedures, and immunosuppressive therapy as significant AMR risk factors, while infection control and stewardship reduced risk (
P
< 0.05). This study demonstrates a high burden of antimicrobial resistance, primarily mediated by TEM and SHV β-lactamases in
E. coli
and
K. pneumoniae
, and by VIM, NDM, and OXA-48 carbapenemases in
P. aeruginosa
. Additionally, MRSA, VRSA, and VRE showed multidrug resistance. Effective infection control and antibiotic stewardship remain critical to limit the spread of resistant pathogens and to reduce hospital-acquired AMR risk.