Bacterial Infections why so often?

Bacterial Infections are common and one might not be aware of how to treat it until and unless proper diagnosis is done. One cannot really stress the reason for bacterial infections as there are a wide variety of it like skin infections, gastrointestinal infection or respiratory infections caused from various types of bacteria. A weak immune system can be a possible reason though. However in case of any infection, medical assistance should be sought. In most of the cases, antibiotics are prescribed. This follows as a part of health and safety risk assessment.

You need to be cultured to determine the exact infectious bacteria.

my father,aged 71 is a kidney patient and a month back he started having chills ,fever and coughing.Doctor tested TLC 14500 and gram positive cocci ,gram negative bacilli in gram staining .He prescribed antibiotic course for 7 days and TLC went down to 10500 on 7th day.However, after 5 days, again my father had chills and fever ,again TLC was tested,this time 23900.again Dr gave amoxycillin & potassium clavulanate(IV) and tazobactam and piperacillin combination(IV) which is still continued on 13th day but my father is having chills and fever on almost everyday.
What can be the reason of this fever? Malaria test (Blood smear as well as QBC mathod)is negative.The length of fever/chills rules out viral infection as I have been told.Meanwhile,Createnine level has gone up to 2.8.BP is under control. Recently,Dr has also given antifungal medicine and 2 doses are taken but chills and fever (about 102)continues.

The source of the infection has not been found and it continues to reseed his blood stream. In Dialysis patients a common cause of sepsis is his access catheter. Have they cultured and/or Removed it. As an ICU nurse this is a common source and without removal he may not get better.